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Code Issues 8 Releases Wiki Polls Activity

fix subrepo break change

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release/v0.9
Unknwon 9 years ago
parent befed9c20c
commit 216f0477b5
60 changed files with 15372 additions and 1 deletions
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615
modules/crypto/ssh/agent/client.go
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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
/*
Package agent implements a client to an ssh-agent daemon.
References:
[PROTOCOL.agent]: http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL.agent?rev=HEAD
*/
package agent // import "golang.org/x/crypto/ssh/agent"
import (
"bytes"
"crypto/dsa"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rsa"
"encoding/base64"
"encoding/binary"
"errors"
"fmt"
"io"
"math/big"
"sync"
"github.com/gogits/gogs/modules/crypto/ssh"
)
// Agent represents the capabilities of an ssh-agent.
type Agent interface {
// List returns the identities known to the agent.
List() ([]*Key, error)
// Sign has the agent sign the data using a protocol 2 key as defined
// in [PROTOCOL.agent] section 2.6.2.
Sign(key ssh.PublicKey, data []byte) (*ssh.Signature, error)
// Add adds a private key to the agent.
Add(key AddedKey) error
// Remove removes all identities with the given public key.
Remove(key ssh.PublicKey) error
// RemoveAll removes all identities.
RemoveAll() error
// Lock locks the agent. Sign and Remove will fail, and List will empty an empty list.
Lock(passphrase []byte) error
// Unlock undoes the effect of Lock
Unlock(passphrase []byte) error
// Signers returns signers for all the known keys.
Signers() ([]ssh.Signer, error)
}
// AddedKey describes an SSH key to be added to an Agent.
type AddedKey struct {
// PrivateKey must be a *rsa.PrivateKey, *dsa.PrivateKey or
// *ecdsa.PrivateKey, which will be inserted into the agent.
PrivateKey interface{}
// Certificate, if not nil, is communicated to the agent and will be
// stored with the key.
Certificate *ssh.Certificate
// Comment is an optional, free-form string.
Comment string
// LifetimeSecs, if not zero, is the number of seconds that the
// agent will store the key for.
LifetimeSecs uint32
// ConfirmBeforeUse, if true, requests that the agent confirm with the
// user before each use of this key.
ConfirmBeforeUse bool
}
// See [PROTOCOL.agent], section 3.
const (
agentRequestV1Identities = 1
// 3.2 Requests from client to agent for protocol 2 key operations
agentAddIdentity = 17
agentRemoveIdentity = 18
agentRemoveAllIdentities = 19
agentAddIdConstrained = 25
// 3.3 Key-type independent requests from client to agent
agentAddSmartcardKey = 20
agentRemoveSmartcardKey = 21
agentLock = 22
agentUnlock = 23
agentAddSmartcardKeyConstrained = 26
// 3.7 Key constraint identifiers
agentConstrainLifetime = 1
agentConstrainConfirm = 2
)
// maxAgentResponseBytes is the maximum agent reply size that is accepted. This
// is a sanity check, not a limit in the spec.
const maxAgentResponseBytes = 16 << 20
// Agent messages:
// These structures mirror the wire format of the corresponding ssh agent
// messages found in [PROTOCOL.agent].
// 3.4 Generic replies from agent to client
const agentFailure = 5
type failureAgentMsg struct{}
const agentSuccess = 6
type successAgentMsg struct{}
// See [PROTOCOL.agent], section 2.5.2.
const agentRequestIdentities = 11
type requestIdentitiesAgentMsg struct{}
// See [PROTOCOL.agent], section 2.5.2.
const agentIdentitiesAnswer = 12
type identitiesAnswerAgentMsg struct {
NumKeys uint32 `sshtype:"12"`
Keys []byte `ssh:"rest"`
}
// See [PROTOCOL.agent], section 2.6.2.
const agentSignRequest = 13
type signRequestAgentMsg struct {
KeyBlob []byte `sshtype:"13"`
Data []byte
Flags uint32
}
// See [PROTOCOL.agent], section 2.6.2.
// 3.6 Replies from agent to client for protocol 2 key operations
const agentSignResponse = 14
type signResponseAgentMsg struct {
SigBlob []byte `sshtype:"14"`
}
type publicKey struct {
Format string
Rest []byte `ssh:"rest"`
}
// Key represents a protocol 2 public key as defined in
// [PROTOCOL.agent], section 2.5.2.
type Key struct {
Format string
Blob []byte
Comment string
}
func clientErr(err error) error {
return fmt.Errorf("agent: client error: %v", err)
}
// String returns the storage form of an agent key with the format, base64
// encoded serialized key, and the comment if it is not empty.
func (k *Key) String() string {
s := string(k.Format) + " " + base64.StdEncoding.EncodeToString(k.Blob)
if k.Comment != "" {
s += " " + k.Comment
}
return s
}
// Type returns the public key type.
func (k *Key) Type() string {
return k.Format
}
// Marshal returns key blob to satisfy the ssh.PublicKey interface.
func (k *Key) Marshal() []byte {
return k.Blob
}
// Verify satisfies the ssh.PublicKey interface, but is not
// implemented for agent keys.
func (k *Key) Verify(data []byte, sig *ssh.Signature) error {
return errors.New("agent: agent key does not know how to verify")
}
type wireKey struct {
Format string
Rest []byte `ssh:"rest"`
}
func parseKey(in []byte) (out *Key, rest []byte, err error) {
var record struct {
Blob []byte
Comment string
Rest []byte `ssh:"rest"`
}
if err := ssh.Unmarshal(in, &record); err != nil {
return nil, nil, err
}
var wk wireKey
if err := ssh.Unmarshal(record.Blob, &wk); err != nil {
return nil, nil, err
}
return &Key{
Format: wk.Format,
Blob: record.Blob,
Comment: record.Comment,
}, record.Rest, nil
}
// client is a client for an ssh-agent process.
type client struct {
// conn is typically a *net.UnixConn
conn io.ReadWriter
// mu is used to prevent concurrent access to the agent
mu sync.Mutex
}
// NewClient returns an Agent that talks to an ssh-agent process over
// the given connection.
func NewClient(rw io.ReadWriter) Agent {
return &client{conn: rw}
}
// call sends an RPC to the agent. On success, the reply is
// unmarshaled into reply and replyType is set to the first byte of
// the reply, which contains the type of the message.
func (c *client) call(req []byte) (reply interface{}, err error) {
c.mu.Lock()
defer c.mu.Unlock()
msg := make([]byte, 4+len(req))
binary.BigEndian.PutUint32(msg, uint32(len(req)))
copy(msg[4:], req)
if _, err = c.conn.Write(msg); err != nil {
return nil, clientErr(err)
}
var respSizeBuf [4]byte
if _, err = io.ReadFull(c.conn, respSizeBuf[:]); err != nil {
return nil, clientErr(err)
}
respSize := binary.BigEndian.Uint32(respSizeBuf[:])
if respSize > maxAgentResponseBytes {
return nil, clientErr(err)
}
buf := make([]byte, respSize)
if _, err = io.ReadFull(c.conn, buf); err != nil {
return nil, clientErr(err)
}
reply, err = unmarshal(buf)
if err != nil {
return nil, clientErr(err)
}
return reply, err
}
func (c *client) simpleCall(req []byte) error {
resp, err := c.call(req)
if err != nil {
return err
}
if _, ok := resp.(*successAgentMsg); ok {
return nil
}
return errors.New("agent: failure")
}
func (c *client) RemoveAll() error {
return c.simpleCall([]byte{agentRemoveAllIdentities})
}
func (c *client) Remove(key ssh.PublicKey) error {
req := ssh.Marshal(&agentRemoveIdentityMsg{
KeyBlob: key.Marshal(),
})
return c.simpleCall(req)
}
func (c *client) Lock(passphrase []byte) error {
req := ssh.Marshal(&agentLockMsg{
Passphrase: passphrase,
})
return c.simpleCall(req)
}
func (c *client) Unlock(passphrase []byte) error {
req := ssh.Marshal(&agentUnlockMsg{
Passphrase: passphrase,
})
return c.simpleCall(req)
}
// List returns the identities known to the agent.
func (c *client) List() ([]*Key, error) {
// see [PROTOCOL.agent] section 2.5.2.
req := []byte{agentRequestIdentities}
msg, err := c.call(req)
if err != nil {
return nil, err
}
switch msg := msg.(type) {
case *identitiesAnswerAgentMsg:
if msg.NumKeys > maxAgentResponseBytes/8 {
return nil, errors.New("agent: too many keys in agent reply")
}
keys := make([]*Key, msg.NumKeys)
data := msg.Keys
for i := uint32(0); i < msg.NumKeys; i++ {
var key *Key
var err error
if key, data, err = parseKey(data); err != nil {
return nil, err
}
keys[i] = key
}
return keys, nil
case *failureAgentMsg:
return nil, errors.New("agent: failed to list keys")
}
panic("unreachable")
}
// Sign has the agent sign the data using a protocol 2 key as defined
// in [PROTOCOL.agent] section 2.6.2.
func (c *client) Sign(key ssh.PublicKey, data []byte) (*ssh.Signature, error) {
req := ssh.Marshal(signRequestAgentMsg{
KeyBlob: key.Marshal(),
Data: data,
})
msg, err := c.call(req)
if err != nil {
return nil, err
}
switch msg := msg.(type) {
case *signResponseAgentMsg:
var sig ssh.Signature
if err := ssh.Unmarshal(msg.SigBlob, &sig); err != nil {
return nil, err
}
return &sig, nil
case *failureAgentMsg:
return nil, errors.New("agent: failed to sign challenge")
}
panic("unreachable")
}
// unmarshal parses an agent message in packet, returning the parsed
// form and the message type of packet.
func unmarshal(packet []byte) (interface{}, error) {
if len(packet) < 1 {
return nil, errors.New("agent: empty packet")
}
var msg interface{}
switch packet[0] {
case agentFailure:
return new(failureAgentMsg), nil
case agentSuccess:
return new(successAgentMsg), nil
case agentIdentitiesAnswer:
msg = new(identitiesAnswerAgentMsg)
case agentSignResponse:
msg = new(signResponseAgentMsg)
default:
return nil, fmt.Errorf("agent: unknown type tag %d", packet[0])
}
if err := ssh.Unmarshal(packet, msg); err != nil {
return nil, err
}
return msg, nil
}
type rsaKeyMsg struct {
Type string `sshtype:"17"`
N *big.Int
E *big.Int
D *big.Int
Iqmp *big.Int // IQMP = Inverse Q Mod P
P *big.Int
Q *big.Int
Comments string
Constraints []byte `ssh:"rest"`
}
type dsaKeyMsg struct {
Type string `sshtype:"17"`
P *big.Int
Q *big.Int
G *big.Int
Y *big.Int
X *big.Int
Comments string
Constraints []byte `ssh:"rest"`
}
type ecdsaKeyMsg struct {
Type string `sshtype:"17"`
Curve string
KeyBytes []byte
D *big.Int
Comments string
Constraints []byte `ssh:"rest"`
}
// Insert adds a private key to the agent.
func (c *client) insertKey(s interface{}, comment string, constraints []byte) error {
var req []byte
switch k := s.(type) {
case *rsa.PrivateKey:
if len(k.Primes) != 2 {
return fmt.Errorf("agent: unsupported RSA key with %d primes", len(k.Primes))
}
k.Precompute()
req = ssh.Marshal(rsaKeyMsg{
Type: ssh.KeyAlgoRSA,
N: k.N,
E: big.NewInt(int64(k.E)),
D: k.D,
Iqmp: k.Precomputed.Qinv,
P: k.Primes[0],
Q: k.Primes[1],
Comments: comment,
Constraints: constraints,
})
case *dsa.PrivateKey:
req = ssh.Marshal(dsaKeyMsg{
Type: ssh.KeyAlgoDSA,
P: k.P,
Q: k.Q,
G: k.G,
Y: k.Y,
X: k.X,
Comments: comment,
Constraints: constraints,
})
case *ecdsa.PrivateKey:
nistID := fmt.Sprintf("nistp%d", k.Params().BitSize)
req = ssh.Marshal(ecdsaKeyMsg{
Type: "ecdsa-sha2-" + nistID,
Curve: nistID,
KeyBytes: elliptic.Marshal(k.Curve, k.X, k.Y),
D: k.D,
Comments: comment,
Constraints: constraints,
})
default:
return fmt.Errorf("agent: unsupported key type %T", s)
}
// if constraints are present then the message type needs to be changed.
if len(constraints) != 0 {
req[0] = agentAddIdConstrained
}
resp, err := c.call(req)
if err != nil {
return err
}
if _, ok := resp.(*successAgentMsg); ok {
return nil
}
return errors.New("agent: failure")
}
type rsaCertMsg struct {
Type string `sshtype:"17"`
CertBytes []byte
D *big.Int
Iqmp *big.Int // IQMP = Inverse Q Mod P
P *big.Int
Q *big.Int
Comments string
Constraints []byte `ssh:"rest"`
}
type dsaCertMsg struct {
Type string `sshtype:"17"`
CertBytes []byte
X *big.Int
Comments string
Constraints []byte `ssh:"rest"`
}
type ecdsaCertMsg struct {
Type string `sshtype:"17"`
CertBytes []byte
D *big.Int
Comments string
Constraints []byte `ssh:"rest"`
}
// Insert adds a private key to the agent. If a certificate is given,
// that certificate is added instead as public key.
func (c *client) Add(key AddedKey) error {
var constraints []byte
if secs := key.LifetimeSecs; secs != 0 {
constraints = append(constraints, agentConstrainLifetime)
var secsBytes [4]byte
binary.BigEndian.PutUint32(secsBytes[:], secs)
constraints = append(constraints, secsBytes[:]...)
}
if key.ConfirmBeforeUse {
constraints = append(constraints, agentConstrainConfirm)
}
if cert := key.Certificate; cert == nil {
return c.insertKey(key.PrivateKey, key.Comment, constraints)
} else {
return c.insertCert(key.PrivateKey, cert, key.Comment, constraints)
}
}
func (c *client) insertCert(s interface{}, cert *ssh.Certificate, comment string, constraints []byte) error {
var req []byte
switch k := s.(type) {
case *rsa.PrivateKey:
if len(k.Primes) != 2 {
return fmt.Errorf("agent: unsupported RSA key with %d primes", len(k.Primes))
}
k.Precompute()
req = ssh.Marshal(rsaCertMsg{
Type: cert.Type(),
CertBytes: cert.Marshal(),
D: k.D,
Iqmp: k.Precomputed.Qinv,
P: k.Primes[0],
Q: k.Primes[1],
Comments: comment,
Constraints: constraints,
})
case *dsa.PrivateKey:
req = ssh.Marshal(dsaCertMsg{
Type: cert.Type(),
CertBytes: cert.Marshal(),
X: k.X,
Comments: comment,
})
case *ecdsa.PrivateKey:
req = ssh.Marshal(ecdsaCertMsg{
Type: cert.Type(),
CertBytes: cert.Marshal(),
D: k.D,
Comments: comment,
})
default:
return fmt.Errorf("agent: unsupported key type %T", s)
}
// if constraints are present then the message type needs to be changed.
if len(constraints) != 0 {
req[0] = agentAddIdConstrained
}
signer, err := ssh.NewSignerFromKey(s)
if err != nil {
return err
}
if bytes.Compare(cert.Key.Marshal(), signer.PublicKey().Marshal()) != 0 {
return errors.New("agent: signer and cert have different public key")
}
resp, err := c.call(req)
if err != nil {
return err
}
if _, ok := resp.(*successAgentMsg); ok {
return nil
}
return errors.New("agent: failure")
}
// Signers provides a callback for client authentication.
func (c *client) Signers() ([]ssh.Signer, error) {
keys, err := c.List()
if err != nil {
return nil, err
}
var result []ssh.Signer
for _, k := range keys {
result = append(result, &agentKeyringSigner{c, k})
}
return result, nil
}
type agentKeyringSigner struct {
agent *client
pub ssh.PublicKey
}
func (s *agentKeyringSigner) PublicKey() ssh.PublicKey {
return s.pub
}
func (s *agentKeyringSigner) Sign(rand io.Reader, data []byte) (*ssh.Signature, error) {
// The agent has its own entropy source, so the rand argument is ignored.
return s.agent.Sign(s.pub, data)
}

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modules/crypto/ssh/agent/client_test.go
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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package agent
import (
"bytes"
"crypto/rand"
"errors"
"net"
"os"
"os/exec"
"path/filepath"
"strconv"
"testing"
"github.com/gogits/gogs/modules/crypto/ssh"
)
// startAgent executes ssh-agent, and returns a Agent interface to it.
func startAgent(t *testing.T) (client Agent, socket string, cleanup func()) {
if testing.Short() {
// ssh-agent is not always available, and the key
// types supported vary by platform.
t.Skip("skipping test due to -short")
}
bin, err := exec.LookPath("ssh-agent")
if err != nil {
t.Skip("could not find ssh-agent")
}
cmd := exec.Command(bin, "-s")
out, err := cmd.Output()
if err != nil {
t.Fatalf("cmd.Output: %v", err)
}
/* Output looks like:
SSH_AUTH_SOCK=/tmp/ssh-P65gpcqArqvH/agent.15541; export SSH_AUTH_SOCK;
SSH_AGENT_PID=15542; export SSH_AGENT_PID;
echo Agent pid 15542;
*/
fields := bytes.Split(out, []byte(";"))
line := bytes.SplitN(fields[0], []byte("="), 2)
line[0] = bytes.TrimLeft(line[0], "\n")
if string(line[0]) != "SSH_AUTH_SOCK" {
t.Fatalf("could not find key SSH_AUTH_SOCK in %q", fields[0])
}
socket = string(line[1])
line = bytes.SplitN(fields[2], []byte("="), 2)
line[0] = bytes.TrimLeft(line[0], "\n")
if string(line[0]) != "SSH_AGENT_PID" {
t.Fatalf("could not find key SSH_AGENT_PID in %q", fields[2])
}
pidStr := line[1]
pid, err := strconv.Atoi(string(pidStr))
if err != nil {
t.Fatalf("Atoi(%q): %v", pidStr, err)
}
conn, err := net.Dial("unix", string(socket))
if err != nil {
t.Fatalf("net.Dial: %v", err)
}
ac := NewClient(conn)
return ac, socket, func() {
proc, _ := os.FindProcess(pid)
if proc != nil {
proc.Kill()
}
conn.Close()
os.RemoveAll(filepath.Dir(socket))
}
}
func testAgent(t *testing.T, key interface{}, cert *ssh.Certificate, lifetimeSecs uint32) {
agent, _, cleanup := startAgent(t)
defer cleanup()
testAgentInterface(t, agent, key, cert, lifetimeSecs)
}
func testAgentInterface(t *testing.T, agent Agent, key interface{}, cert *ssh.Certificate, lifetimeSecs uint32) {
signer, err := ssh.NewSignerFromKey(key)
if err != nil {
t.Fatalf("NewSignerFromKey(%T): %v", key, err)
}
// The agent should start up empty.
if keys, err := agent.List(); err != nil {
t.Fatalf("RequestIdentities: %v", err)
} else if len(keys) > 0 {
t.Fatalf("got %d keys, want 0: %v", len(keys), keys)
}
// Attempt to insert the key, with certificate if specified.
var pubKey ssh.PublicKey
if cert != nil {
err = agent.Add(AddedKey{
PrivateKey: key,
Certificate: cert,
Comment: "comment",
LifetimeSecs: lifetimeSecs,
})
pubKey = cert
} else {
err = agent.Add(AddedKey{PrivateKey: key, Comment: "comment", LifetimeSecs: lifetimeSecs})
pubKey = signer.PublicKey()
}
if err != nil {
t.Fatalf("insert(%T): %v", key, err)
}
// Did the key get inserted successfully?
if keys, err := agent.List(); err != nil {
t.Fatalf("List: %v", err)
} else if len(keys) != 1 {
t.Fatalf("got %v, want 1 key", keys)
} else if keys[0].Comment != "comment" {
t.Fatalf("key comment: got %v, want %v", keys[0].Comment, "comment")
} else if !bytes.Equal(keys[0].Blob, pubKey.Marshal()) {
t.Fatalf("key mismatch")
}
// Can the agent make a valid signature?
data := []byte("hello")
sig, err := agent.Sign(pubKey, data)
if err != nil {
t.Fatalf("Sign(%s): %v", pubKey.Type(), err)
}
if err := pubKey.Verify(data, sig); err != nil {
t.Fatalf("Verify(%s): %v", pubKey.Type(), err)
}
}
func TestAgent(t *testing.T) {
for _, keyType := range []string{"rsa", "dsa", "ecdsa"} {
testAgent(t, testPrivateKeys[keyType], nil, 0)
}
}
func TestCert(t *testing.T) {
cert := &ssh.Certificate{
Key: testPublicKeys["rsa"],
ValidBefore: ssh.CertTimeInfinity,
CertType: ssh.UserCert,
}
cert.SignCert(rand.Reader, testSigners["ecdsa"])
testAgent(t, testPrivateKeys["rsa"], cert, 0)
}
func TestConstraints(t *testing.T) {
testAgent(t, testPrivateKeys["rsa"], nil, 3600 /* lifetime in seconds */)
}
// netPipe is analogous to net.Pipe, but it uses a real net.Conn, and
// therefore is buffered (net.Pipe deadlocks if both sides start with
// a write.)
func netPipe() (net.Conn, net.Conn, error) {
listener, err := net.Listen("tcp", "127.0.0.1:0")
if err != nil {
return nil, nil, err
}
defer listener.Close()
c1, err := net.Dial("tcp", listener.Addr().String())
if err != nil {
return nil, nil, err
}
c2, err := listener.Accept()
if err != nil {
c1.Close()
return nil, nil, err
}
return c1, c2, nil
}
func TestAuth(t *testing.T) {
a, b, err := netPipe()
if err != nil {
t.Fatalf("netPipe: %v", err)
}
defer a.Close()
defer b.Close()
agent, _, cleanup := startAgent(t)
defer cleanup()
if err := agent.Add(AddedKey{PrivateKey: testPrivateKeys["rsa"], Comment: "comment"}); err != nil {
t.Errorf("Add: %v", err)
}
serverConf := ssh.ServerConfig{}
serverConf.AddHostKey(testSigners["rsa"])
serverConf.PublicKeyCallback = func(c ssh.ConnMetadata, key ssh.PublicKey) (*ssh.Permissions, error) {
if bytes.Equal(key.Marshal(), testPublicKeys["rsa"].Marshal()) {
return nil, nil
}
return nil, errors.New("pubkey rejected")
}
go func() {
conn, _, _, err := ssh.NewServerConn(a, &serverConf)
if err != nil {
t.Fatalf("Server: %v", err)
}
conn.Close()
}()
conf := ssh.ClientConfig{}
conf.Auth = append(conf.Auth, ssh.PublicKeysCallback(agent.Signers))
conn, _, _, err := ssh.NewClientConn(b, "", &conf)
if err != nil {
t.Fatalf("NewClientConn: %v", err)
}
conn.Close()
}
func TestLockClient(t *testing.T) {
agent, _, cleanup := startAgent(t)
defer cleanup()
testLockAgent(agent, t)
}
func testLockAgent(agent Agent, t *testing.T) {
if err := agent.Add(AddedKey{PrivateKey: testPrivateKeys["rsa"], Comment: "comment 1"}); err != nil {
t.Errorf("Add: %v", err)
}
if err := agent.Add(AddedKey{PrivateKey: testPrivateKeys["dsa"], Comment: "comment dsa"}); err != nil {
t.Errorf("Add: %v", err)
}
if keys, err := agent.List(); err != nil {
t.Errorf("List: %v", err)
} else if len(keys) != 2 {
t.Errorf("Want 2 keys, got %v", keys)
}
passphrase := []byte("secret")
if err := agent.Lock(passphrase); err != nil {
t.Errorf("Lock: %v", err)
}
if keys, err := agent.List(); err != nil {
t.Errorf("List: %v", err)
} else if len(keys) != 0 {
t.Errorf("Want 0 keys, got %v", keys)
}
signer, _ := ssh.NewSignerFromKey(testPrivateKeys["rsa"])
if _, err := agent.Sign(signer.PublicKey(), []byte("hello")); err == nil {
t.Fatalf("Sign did not fail")
}
if err := agent.Remove(signer.PublicKey()); err == nil {
t.Fatalf("Remove did not fail")
}
if err := agent.RemoveAll(); err == nil {
t.Fatalf("RemoveAll did not fail")
}
if err := agent.Unlock(nil); err == nil {
t.Errorf("Unlock with wrong passphrase succeeded")
}
if err := agent.Unlock(passphrase); err != nil {
t.Errorf("Unlock: %v", err)
}
if err := agent.Remove(signer.PublicKey()); err != nil {
t.Fatalf("Remove: %v", err)
}
if keys, err := agent.List(); err != nil {
t.Errorf("List: %v", err)
} else if len(keys) != 1 {
t.Errorf("Want 1 keys, got %v", keys)
}
}

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modules/crypto/ssh/agent/forward.go
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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package agent
import (
"errors"
"io"
"net"
"sync"
"github.com/gogits/gogs/modules/crypto/ssh"
)
// RequestAgentForwarding sets up agent forwarding for the session.
// ForwardToAgent or ForwardToRemote should be called to route
// the authentication requests.
func RequestAgentForwarding(session *ssh.Session) error {
ok, err := session.SendRequest("auth-agent-req@openssh.com", true, nil)
if err != nil {
return err
}
if !ok {
return errors.New("forwarding request denied")
}
return nil
}
// ForwardToAgent routes authentication requests to the given keyring.
func ForwardToAgent(client *ssh.Client, keyring Agent) error {
channels := client.HandleChannelOpen(channelType)
if channels == nil {
return errors.New("agent: already have handler for " + channelType)
}
go func() {
for ch := range channels {
channel, reqs, err := ch.Accept()
if err != nil {
continue
}
go ssh.DiscardRequests(reqs)
go func() {
ServeAgent(keyring, channel)
channel.Close()
}()
}
}()
return nil
}
const channelType = "auth-agent@openssh.com"
// ForwardToRemote routes authentication requests to the ssh-agent
// process serving on the given unix socket.
func ForwardToRemote(client *ssh.Client, addr string) error {
channels := client.HandleChannelOpen(channelType)
if channels == nil {
return errors.New("agent: already have handler for " + channelType)
}
conn, err := net.Dial("unix", addr)
if err != nil {
return err
}
conn.Close()
go func() {
for ch := range channels {
channel, reqs, err := ch.Accept()
if err != nil {
continue
}
go ssh.DiscardRequests(reqs)
go forwardUnixSocket(channel, addr)
}
}()
return nil
}
func forwardUnixSocket(channel ssh.Channel, addr string) {
conn, err := net.Dial("unix", addr)
if err != nil {
return
}
var wg sync.WaitGroup
wg.Add(2)
go func() {
io.Copy(conn, channel)
conn.(*net.UnixConn).CloseWrite()
wg.Done()
}()
go func() {
io.Copy(channel, conn)
channel.CloseWrite()
wg.Done()
}()
wg.Wait()
conn.Close()
channel.Close()
}

184
modules/crypto/ssh/agent/keyring.go
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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package agent
import (
"bytes"
"crypto/rand"
"crypto/subtle"
"errors"
"fmt"
"sync"
"github.com/gogits/gogs/modules/crypto/ssh"
)
type privKey struct {
signer ssh.Signer
comment string
}
type keyring struct {
mu sync.Mutex
keys []privKey
locked bool
passphrase []byte
}
var errLocked = errors.New("agent: locked")
// NewKeyring returns an Agent that holds keys in memory. It is safe
// for concurrent use by multiple goroutines.
func NewKeyring() Agent {
return &keyring{}
}
// RemoveAll removes all identities.
func (r *keyring) RemoveAll() error {
r.mu.Lock()
defer r.mu.Unlock()
if r.locked {
return errLocked
}
r.keys = nil
return nil
}
// Remove removes all identities with the given public key.
func (r *keyring) Remove(key ssh.PublicKey) error {
r.mu.Lock()
defer r.mu.Unlock()
if r.locked {
return errLocked
}
want := key.Marshal()
found := false
for i := 0; i < len(r.keys); {
if bytes.Equal(r.keys[i].signer.PublicKey().Marshal(), want) {
found = true
r.keys[i] = r.keys[len(r.keys)-1]
r.keys = r.keys[len(r.keys)-1:]
continue
} else {
i++
}
}
if !found {
return errors.New("agent: key not found")
}
return nil
}
// Lock locks the agent. Sign and Remove will fail, and List will empty an empty list.
func (r *keyring) Lock(passphrase []byte) error {
r.mu.Lock()
defer r.mu.Unlock()
if r.locked {
return errLocked
}
r.locked = true
r.passphrase = passphrase
return nil
}
// Unlock undoes the effect of Lock
func (r *keyring) Unlock(passphrase []byte) error {
r.mu.Lock()
defer r.mu.Unlock()
if !r.locked {
return errors.New("agent: not locked")
}
if len(passphrase) != len(r.passphrase) || 1 != subtle.ConstantTimeCompare(passphrase, r.passphrase) {
return fmt.Errorf("agent: incorrect passphrase")
}
r.locked = false
r.passphrase = nil
return nil
}
// List returns the identities known to the agent.
func (r *keyring) List() ([]*Key, error) {
r.mu.Lock()
defer r.mu.Unlock()
if r.locked {
// section 2.7: locked agents return empty.
return nil, nil
}
var ids []*Key
for _, k := range r.keys {
pub := k.signer.PublicKey()
ids = append(ids, &Key{
Format: pub.Type(),
Blob: pub.Marshal(),
Comment: k.comment})
}
return ids, nil
}
// Insert adds a private key to the keyring. If a certificate
// is given, that certificate is added as public key. Note that
// any constraints given are ignored.
func (r *keyring) Add(key AddedKey) error {
r.mu.Lock()
defer r.mu.Unlock()
if r.locked {
return errLocked
}
signer, err := ssh.NewSignerFromKey(key.PrivateKey)
if err != nil {
return err
}
if cert := key.Certificate; cert != nil {
signer, err = ssh.NewCertSigner(cert, signer)
if err != nil {
return err
}
}
r.keys = append(r.keys, privKey{signer, key.Comment})
return nil
}
// Sign returns a signature for the data.
func (r *keyring) Sign(key ssh.PublicKey, data []byte) (*ssh.Signature, error) {
r.mu.Lock()
defer r.mu.Unlock()
if r.locked {
return nil, errLocked
}
wanted := key.Marshal()
for _, k := range r.keys {
if bytes.Equal(k.signer.PublicKey().Marshal(), wanted) {
return k.signer.Sign(rand.Reader, data)
}
}
return nil, errors.New("not found")
}
// Signers returns signers for all the known keys.
func (r *keyring) Signers() ([]ssh.Signer, error) {
r.mu.Lock()
defer r.mu.Unlock()
if r.locked {
return nil, errLocked
}
s := make([]ssh.Signer, 0, len(r.keys))
for _, k := range r.keys {
s = append(s, k.signer)
}
return s, nil
}

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modules/crypto/ssh/agent/server.go
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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package agent
import (
"crypto/rsa"
"encoding/binary"
"fmt"
"io"
"log"
"math/big"
"github.com/gogits/gogs/modules/crypto/ssh"
)
// Server wraps an Agent and uses it to implement the agent side of
// the SSH-agent, wire protocol.
type server struct {
agent Agent
}
func (s *server) processRequestBytes(reqData []byte) []byte {
rep, err := s.processRequest(reqData)
if err != nil {
if err != errLocked {
// TODO(hanwen): provide better logging interface?
log.Printf("agent %d: %v", reqData[0], err)
}
return []byte{agentFailure}
}
if err == nil && rep == nil {
return []byte{agentSuccess}
}
return ssh.Marshal(rep)
}
func marshalKey(k *Key) []byte {
var record struct {
Blob []byte
Comment string
}
record.Blob = k.Marshal()
record.Comment = k.Comment
return ssh.Marshal(&record)
}
type agentV1IdentityMsg struct {
Numkeys uint32 `sshtype:"2"`
}
type agentRemoveIdentityMsg struct {
KeyBlob []byte `sshtype:"18"`
}
type agentLockMsg struct {
Passphrase []byte `sshtype:"22"`
}
type agentUnlockMsg struct {
Passphrase []byte `sshtype:"23"`
}
func (s *server) processRequest(data []byte) (interface{}, error) {
switch data[0] {
case agentRequestV1Identities:
return &agentV1IdentityMsg{0}, nil
case agentRemoveIdentity:
var req agentRemoveIdentityMsg
if err := ssh.Unmarshal(data, &req); err != nil {
return nil, err
}
var wk wireKey
if err := ssh.Unmarshal(req.KeyBlob, &wk); err != nil {
return nil, err
}
return nil, s.agent.Remove(&Key{Format: wk.Format, Blob: req.KeyBlob})
case agentRemoveAllIdentities:
return nil, s.agent.RemoveAll()
case agentLock:
var req agentLockMsg
if err := ssh.Unmarshal(data, &req); err != nil {
return nil, err
}
return nil, s.agent.Lock(req.Passphrase)
case agentUnlock:
var req agentLockMsg
if err := ssh.Unmarshal(data, &req); err != nil {
return nil, err
}
return nil, s.agent.Unlock(req.Passphrase)
case agentSignRequest:
var req signRequestAgentMsg
if err := ssh.Unmarshal(data, &req); err != nil {
return nil, err
}
var wk wireKey
if err := ssh.Unmarshal(req.KeyBlob, &wk); err != nil {
return nil, err
}
k := &Key{
Format: wk.Format,
Blob: req.KeyBlob,
}
sig, err := s.agent.Sign(k, req.Data) // TODO(hanwen): flags.
if err != nil {
return nil, err
}
return &signResponseAgentMsg{SigBlob: ssh.Marshal(sig)}, nil
case agentRequestIdentities:
keys, err := s.agent.List()
if err != nil {
return nil, err
}
rep := identitiesAnswerAgentMsg{
NumKeys: uint32(len(keys)),
}
for _, k := range keys {
rep.Keys = append(rep.Keys, marshalKey(k)...)
}
return rep, nil
case agentAddIdentity:
return nil, s.insertIdentity(data)
}
return nil, fmt.Errorf("unknown opcode %d", data[0])
}
func (s *server) insertIdentity(req []byte) error {
var record struct {
Type string `sshtype:"17"`
Rest []byte `ssh:"rest"`
}
if err := ssh.Unmarshal(req, &record); err != nil {
return err
}
switch record.Type {
case ssh.KeyAlgoRSA:
var k rsaKeyMsg
if err := ssh.Unmarshal(req, &k); err != nil {
return err
}
priv := rsa.PrivateKey{
PublicKey: rsa.PublicKey{
E: int(k.E.Int64()),
N: k.N,
},
D: k.D,
Primes: []*big.Int{k.P, k.Q},
}
priv.Precompute()
return s.agent.Add(AddedKey{PrivateKey: &priv, Comment: k.Comments})
}
return fmt.Errorf("not implemented: %s", record.Type)
}
// ServeAgent serves the agent protocol on the given connection. It
// returns when an I/O error occurs.
func ServeAgent(agent Agent, c io.ReadWriter) error {
s := &server{agent}
var length [4]byte
for {
if _, err := io.ReadFull(c, length[:]); err != nil {
return err
}
l := binary.BigEndian.Uint32(length[:])
if l > maxAgentResponseBytes {
// We also cap requests.
return fmt.Errorf("agent: request too large: %d", l)
}
req := make([]byte, l)
if _, err := io.ReadFull(c, req); err != nil {
return err
}
repData := s.processRequestBytes(req)
if len(repData) > maxAgentResponseBytes {
return fmt.Errorf("agent: reply too large: %d bytes", len(repData))
}
binary.BigEndian.PutUint32(length[:], uint32(len(repData)))
if _, err := c.Write(length[:]); err != nil {
return err
}
if _, err := c.Write(repData); err != nil {
return err
}
}
}

77
modules/crypto/ssh/agent/server_test.go
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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package agent
import (
"testing"
"github.com/gogits/gogs/modules/crypto/ssh"
)
func TestServer(t *testing.T) {
c1, c2, err := netPipe()
if err != nil {
t.Fatalf("netPipe: %v", err)
}
defer c1.Close()
defer c2.Close()
client := NewClient(c1)
go ServeAgent(NewKeyring(), c2)
testAgentInterface(t, client, testPrivateKeys["rsa"], nil, 0)
}
func TestLockServer(t *testing.T) {
testLockAgent(NewKeyring(), t)
}
func TestSetupForwardAgent(t *testing.T) {
a, b, err := netPipe()
if err != nil {
t.Fatalf("netPipe: %v", err)
}
defer a.Close()
defer b.Close()
_, socket, cleanup := startAgent(t)
defer cleanup()
serverConf := ssh.ServerConfig{
NoClientAuth: true,
}
serverConf.AddHostKey(testSigners["rsa"])
incoming := make(chan *ssh.ServerConn, 1)
go func() {
conn, _, _, err := ssh.NewServerConn(a, &serverConf)
if err != nil {
t.Fatalf("Server: %v", err)
}
incoming <- conn
}()
conf := ssh.ClientConfig{}
conn, chans, reqs, err := ssh.NewClientConn(b, "", &conf)
if err != nil {
t.Fatalf("NewClientConn: %v", err)
}
client := ssh.NewClient(conn, chans, reqs)
if err := ForwardToRemote(client, socket); err != nil {
t.Fatalf("SetupForwardAgent: %v", err)
}
server := <-incoming
ch, reqs, err := server.OpenChannel(channelType, nil)
if err != nil {
t.Fatalf("OpenChannel(%q): %v", channelType, err)
}
go ssh.DiscardRequests(reqs)
agentClient := NewClient(ch)
testAgentInterface(t, agentClient, testPrivateKeys["rsa"], nil, 0)
conn.Close()
}

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modules/crypto/ssh/agent/testdata_test.go
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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// IMPLEMENTOR NOTE: To avoid a package loop, this file is in three places:
// ssh/, ssh/agent, and ssh/test/. It should be kept in sync across all three
// instances.
package agent
import (
"crypto/rand"
"fmt"
"github.com/gogits/gogs/modules/crypto/ssh"
"github.com/gogits/gogs/modules/crypto/ssh/testdata"
)
var (
testPrivateKeys map[string]interface{}
testSigners map[string]ssh.Signer
testPublicKeys map[string]ssh.PublicKey
)
func init() {
var err error
n := len(testdata.PEMBytes)
testPrivateKeys = make(map[string]interface{}, n)
testSigners = make(map[string]ssh.Signer, n)
testPublicKeys = make(map[string]ssh.PublicKey, n)
for t, k := range testdata.PEMBytes {
testPrivateKeys[t], err = ssh.ParseRawPrivateKey(k)
if err != nil {
panic(fmt.Sprintf("Unable to parse test key %s: %v", t, err))
}
testSigners[t], err = ssh.NewSignerFromKey(testPrivateKeys[t])
if err != nil {
panic(fmt.Sprintf("Unable to create signer for test key %s: %v", t, err))
}
testPublicKeys[t] = testSigners[t].PublicKey()
}
// Create a cert and sign it for use in tests.
testCert := &ssh.Certificate{
Nonce: []byte{}, // To pass reflect.DeepEqual after marshal & parse, this must be non-nil
ValidPrincipals: []string{"gopher1", "gopher2"}, // increases test coverage
ValidAfter: 0, // unix epoch
ValidBefore: ssh.CertTimeInfinity, // The end of currently representable time.
Reserved: []byte{}, // To pass reflect.DeepEqual after marshal & parse, this must be non-nil
Key: testPublicKeys["ecdsa"],
SignatureKey: testPublicKeys["rsa"],
Permissions: ssh.Permissions{
CriticalOptions: map[string]string{},
Extensions: map[string]string{},
},
}
testCert.SignCert(rand.Reader, testSigners["rsa"])
testPrivateKeys["cert"] = testPrivateKeys["ecdsa"]
testSigners["cert"], err = ssh.NewCertSigner(testCert, testSigners["ecdsa"])
if err != nil {
panic(fmt.Sprintf("Unable to create certificate signer: %v", err))
}
}

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modules/crypto/ssh/benchmark_test.go
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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"errors"
"io"
"net"
"testing"
)
type server struct {
*ServerConn
chans <-chan NewChannel
}
func newServer(c net.Conn, conf *ServerConfig) (*server, error) {
sconn, chans, reqs, err := NewServerConn(c, conf)
if err != nil {
return nil, err
}
go DiscardRequests(reqs)
return &server{sconn, chans}, nil
}
func (s *server) Accept() (NewChannel, error) {
n, ok := <-s.chans
if !ok {
return nil, io.EOF
}
return n, nil
}
func sshPipe() (Conn, *server, error) {
c1, c2, err := netPipe()
if err != nil {
return nil, nil, err
}
clientConf := ClientConfig{
User: "user",
}
serverConf := ServerConfig{
NoClientAuth: true,
}
serverConf.AddHostKey(testSigners["ecdsa"])
done := make(chan *server, 1)
go func() {
server, err := newServer(c2, &serverConf)
if err != nil {
done <- nil
}
done <- server
}()
client, _, reqs, err := NewClientConn(c1, "", &clientConf)
if err != nil {
return nil, nil, err
}
server := <-done
if server == nil {
return nil, nil, errors.New("server handshake failed.")
}
go DiscardRequests(reqs)
return client, server, nil
}
func BenchmarkEndToEnd(b *testing.B) {
b.StopTimer()
client, server, err := sshPipe()
if err != nil {
b.Fatalf("sshPipe: %v", err)
}
defer client.Close()
defer server.Close()
size := (1 << 20)
input := make([]byte, size)
output := make([]byte, size)
b.SetBytes(int64(size))
done := make(chan int, 1)
go func() {
newCh, err := server.Accept()
if err != nil {
b.Fatalf("Client: %v", err)
}
ch, incoming, err := newCh.Accept()
go DiscardRequests(incoming)
for i := 0; i < b.N; i++ {
if _, err := io.ReadFull(ch, output); err != nil {
b.Fatalf("ReadFull: %v", err)
}
}
ch.Close()
done <- 1
}()
ch, in, err := client.OpenChannel("speed", nil)
if err != nil {
b.Fatalf("OpenChannel: %v", err)
}
go DiscardRequests(in)
b.ResetTimer()
b.StartTimer()
for i := 0; i < b.N; i++ {
if _, err := ch.Write(input); err != nil {
b.Fatalf("WriteFull: %v", err)
}
}
ch.Close()
b.StopTimer()
<-done
}

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modules/crypto/ssh/buffer.go
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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"io"
"sync"
)
// buffer provides a linked list buffer for data exchange
// between producer and consumer. Theoretically the buffer is
// of unlimited capacity as it does no allocation of its own.
type buffer struct {
// protects concurrent access to head, tail and closed
*sync.Cond
head *element // the buffer that will be read first
tail *element // the buffer that will be read last
closed bool
}
// An element represents a single link in a linked list.
type element struct {
buf []byte
next *element
}
// newBuffer returns an empty buffer that is not closed.
func newBuffer() *buffer {
e := new(element)
b := &buffer{
Cond: newCond(),
head: e,
tail: e,
}
return b
}
// write makes buf available for Read to receive.
// buf must not be modified after the call to write.
func (b *buffer) write(buf []byte) {
b.Cond.L.Lock()
e := &element{buf: buf}
b.tail.next = e
b.tail = e
b.Cond.Signal()
b.Cond.L.Unlock()
}
// eof closes the buffer. Reads from the buffer once all
// the data has been consumed will receive os.EOF.
func (b *buffer) eof() error {
b.Cond.L.Lock()
b.closed = true
b.Cond.Signal()
b.Cond.L.Unlock()
return nil
}
// Read reads data from the internal buffer in buf. Reads will block
// if no data is available, or until the buffer is closed.
func (b *buffer) Read(buf []byte) (n int, err error) {
b.Cond.L.Lock()
defer b.Cond.L.Unlock()
for len(buf) > 0 {
// if there is data in b.head, copy it
if len(b.head.buf) > 0 {
r := copy(buf, b.head.buf)
buf, b.head.buf = buf[r:], b.head.buf[r:]
n += r
continue
}
// if there is a next buffer, make it the head
if len(b.head.buf) == 0 && b.head != b.tail {
b.head = b.head.next
continue
}
// if at least one byte has been copied, return
if n > 0 {
break
}
// if nothing was read, and there is nothing outstanding
// check to see if the buffer is closed.
if b.closed {
err = io.EOF
break
}
// out of buffers, wait for producer
b.Cond.Wait()
}
return
}

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modules/crypto/ssh/buffer_test.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"io"
"testing"
)
var alphabet = []byte("abcdefghijklmnopqrstuvwxyz")
func TestBufferReadwrite(t *testing.T) {
b := newBuffer()
b.write(alphabet[:10])
r, _ := b.Read(make([]byte, 10))
if r != 10 {
t.Fatalf("Expected written == read == 10, written: 10, read %d", r)
}
b = newBuffer()
b.write(alphabet[:5])
r, _ = b.Read(make([]byte, 10))
if r != 5 {
t.Fatalf("Expected written == read == 5, written: 5, read %d", r)
}
b = newBuffer()
b.write(alphabet[:10])
r, _ = b.Read(make([]byte, 5))
if r != 5 {
t.Fatalf("Expected written == 10, read == 5, written: 10, read %d", r)
}
b = newBuffer()
b.write(alphabet[:5])
b.write(alphabet[5:15])
r, _ = b.Read(make([]byte, 10))
r2, _ := b.Read(make([]byte, 10))
if r != 10 || r2 != 5 || 15 != r+r2 {
t.Fatal("Expected written == read == 15")
}
}
func TestBufferClose(t *testing.T) {
b := newBuffer()
b.write(alphabet[:10])
b.eof()
_, err := b.Read(make([]byte, 5))
if err != nil {
t.Fatal("expected read of 5 to not return EOF")
}
b = newBuffer()
b.write(alphabet[:10])
b.eof()
r, err := b.Read(make([]byte, 5))
r2, err2 := b.Read(make([]byte, 10))
if r != 5 || r2 != 5 || err != nil || err2 != nil {
t.Fatal("expected reads of 5 and 5")
}
b = newBuffer()
b.write(alphabet[:10])
b.eof()
r, err = b.Read(make([]byte, 5))
r2, err2 = b.Read(make([]byte, 10))
r3, err3 := b.Read(make([]byte, 10))
if r != 5 || r2 != 5 || r3 != 0 || err != nil || err2 != nil || err3 != io.EOF {
t.Fatal("expected reads of 5 and 5 and 0, with EOF")
}
b = newBuffer()
b.write(make([]byte, 5))
b.write(make([]byte, 10))
b.eof()
r, err = b.Read(make([]byte, 9))
r2, err2 = b.Read(make([]byte, 3))
r3, err3 = b.Read(make([]byte, 3))
r4, err4 := b.Read(make([]byte, 10))
if err != nil || err2 != nil || err3 != nil || err4 != io.EOF {
t.Fatalf("Expected EOF on forth read only, err=%v, err2=%v, err3=%v, err4=%v", err, err2, err3, err4)
}
if r != 9 || r2 != 3 || r3 != 3 || r4 != 0 {
t.Fatal("Expected written == read == 15", r, r2, r3, r4)
}
}

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modules/crypto/ssh/certs.go
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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"bytes"
"errors"
"fmt"
"io"
"net"
"sort"
"time"
)
// These constants from [PROTOCOL.certkeys] represent the algorithm names
// for certificate types supported by this package.
const (
CertAlgoRSAv01 = "ssh-rsa-cert-v01@openssh.com"
CertAlgoDSAv01 = "ssh-dss-cert-v01@openssh.com"
CertAlgoECDSA256v01 = "ecdsa-sha2-nistp256-cert-v01@openssh.com"
CertAlgoECDSA384v01 = "ecdsa-sha2-nistp384-cert-v01@openssh.com"
CertAlgoECDSA521v01 = "ecdsa-sha2-nistp521-cert-v01@openssh.com"
)
// Certificate types distinguish between host and user
// certificates. The values can be set in the CertType field of
// Certificate.
const (
UserCert = 1
HostCert = 2
)
// Signature represents a cryptographic signature.
type Signature struct {
Format string
Blob []byte
}
// CertTimeInfinity can be used for OpenSSHCertV01.ValidBefore to indicate that
// a certificate does not expire.
const CertTimeInfinity = 1<<64 - 1
// An Certificate represents an OpenSSH certificate as defined in
// [PROTOCOL.certkeys]?rev=1.8.
type Certificate struct {
Nonce []byte
Key PublicKey
Serial uint64
CertType uint32
KeyId string
ValidPrincipals []string
ValidAfter uint64
ValidBefore uint64
Permissions
Reserved []byte
SignatureKey PublicKey
Signature *Signature
}
// genericCertData holds the key-independent part of the certificate data.
// Overall, certificates contain an nonce, public key fields and
// key-independent fields.
type genericCertData struct {
Serial uint64
CertType uint32
KeyId string
ValidPrincipals []byte
ValidAfter uint64
ValidBefore uint64
CriticalOptions []byte
Extensions []byte
Reserved []byte
SignatureKey []byte
Signature []byte
}
func marshalStringList(namelist []string) []byte {
var to []byte
for _, name := range namelist {
s := struct{ N string }{name}
to = append(to, Marshal(&s)...)
}
return to
}
type optionsTuple struct {
Key string
Value []byte
}
type optionsTupleValue struct {
Value string
}
// serialize a map of critical options or extensions
// issue #10569 - per [PROTOCOL.certkeys] and SSH implementation,
// we need two length prefixes for a non-empty string value
func marshalTuples(tups map[string]string) []byte {
keys := make([]string, 0, len(tups))
for key := range tups {
keys = append(keys, key)
}
sort.Strings(keys)
var ret []byte
for _, key := range keys {
s := optionsTuple{Key: key}
if value := tups[key]; len(value) > 0 {
s.Value = Marshal(&optionsTupleValue{value})
}
ret = append(ret, Marshal(&s)...)
}
return ret
}
// issue #10569 - per [PROTOCOL.certkeys] and SSH implementation,
// we need two length prefixes for a non-empty option value
func parseTuples(in []byte) (map[string]string, error) {
tups := map[string]string{}
var lastKey string
var haveLastKey bool
for len(in) > 0 {
var key, val, extra []byte
var ok bool
if key, in, ok = parseString(in); !ok {
return nil, errShortRead
}
keyStr := string(key)
// according to [PROTOCOL.certkeys], the names must be in
// lexical order.
if haveLastKey && keyStr <= lastKey {
return nil, fmt.Errorf("ssh: certificate options are not in lexical order")
}
lastKey, haveLastKey = keyStr, true
// the next field is a data field, which if non-empty has a string embedded
if val, in, ok = parseString(in); !ok {
return nil, errShortRead
}
if len(val) > 0 {
val, extra, ok = parseString(val)
if !ok {
return nil, errShortRead
}
if len(extra) > 0 {
return nil, fmt.Errorf("ssh: unexpected trailing data after certificate option value")
}
tups[keyStr] = string(val)
} else {
tups[keyStr] = ""
}
}
return tups, nil
}
func parseCert(in []byte, privAlgo string) (*Certificate, error) {
nonce, rest, ok := parseString(in)
if !ok {
return nil, errShortRead
}
key, rest, err := parsePubKey(rest, privAlgo)
if err != nil {
return nil, err
}
var g genericCertData
if err := Unmarshal(rest, &g); err != nil {
return nil, err
}
c := &Certificate{
Nonce: nonce,
Key: key,
Serial: g.Serial,
CertType: g.CertType,
KeyId: g.KeyId,
ValidAfter: g.ValidAfter,
ValidBefore: g.ValidBefore,
}
for principals := g.ValidPrincipals; len(principals) > 0; {
principal, rest, ok := parseString(principals)
if !ok {
return nil, errShortRead
}
c.ValidPrincipals = append(c.ValidPrincipals, string(principal))
principals = rest
}
c.CriticalOptions, err = parseTuples(g.CriticalOptions)
if err != nil {
return nil, err
}
c.Extensions, err = parseTuples(g.Extensions)
if err != nil {
return nil, err
}
c.Reserved = g.Reserved
k, err := ParsePublicKey(g.SignatureKey)
if err != nil {
return nil, err
}
c.SignatureKey = k
c.Signature, rest, ok = parseSignatureBody(g.Signature)
if !ok || len(rest) > 0 {
return nil, errors.New("ssh: signature parse error")
}
return c, nil
}
type openSSHCertSigner struct {
pub *Certificate
signer Signer
}
// NewCertSigner returns a Signer that signs with the given Certificate, whose
// private key is held by signer. It returns an error if the public key in cert
// doesn't match the key used by signer.
func NewCertSigner(cert *Certificate, signer Signer) (Signer, error) {
if bytes.Compare(cert.Key.Marshal(), signer.PublicKey().Marshal()) != 0 {
return nil, errors.New("ssh: signer and cert have different public key")
}
return &openSSHCertSigner{cert, signer}, nil
}
func (s *openSSHCertSigner) Sign(rand io.Reader, data []byte) (*Signature, error) {
return s.signer.Sign(rand, data)
}
func (s *openSSHCertSigner) PublicKey() PublicKey {
return s.pub
}
const sourceAddressCriticalOption = "source-address"
// CertChecker does the work of verifying a certificate. Its methods
// can be plugged into ClientConfig.HostKeyCallback and
// ServerConfig.PublicKeyCallback. For the CertChecker to work,
// minimally, the IsAuthority callback should be set.
type CertChecker struct {
// SupportedCriticalOptions lists the CriticalOptions that the
// server application layer understands. These are only used
// for user certificates.
SupportedCriticalOptions []string
// IsAuthority should return true if the key is recognized as
// an authority. This allows for certificates to be signed by other
// certificates.
IsAuthority func(auth PublicKey) bool
// Clock is used for verifying time stamps. If nil, time.Now
// is used.
Clock func() time.Time
// UserKeyFallback is called when CertChecker.Authenticate encounters a
// public key that is not a certificate. It must implement validation
// of user keys or else, if nil, all such keys are rejected.
UserKeyFallback func(conn ConnMetadata, key PublicKey) (*Permissions, error)
// HostKeyFallback is called when CertChecker.CheckHostKey encounters a
// public key that is not a certificate. It must implement host key
// validation or else, if nil, all such keys are rejected.
HostKeyFallback func(addr string, remote net.Addr, key PublicKey) error
// IsRevoked is called for each certificate so that revocation checking
// can be implemented. It should return true if the given certificate
// is revoked and false otherwise. If nil, no certificates are
// considered to have been revoked.
IsRevoked func(cert *Certificate) bool
}
// CheckHostKey checks a host key certificate. This method can be
// plugged into ClientConfig.HostKeyCallback.
func (c *CertChecker) CheckHostKey(addr string, remote net.Addr, key PublicKey) error {
cert, ok := key.(*Certificate)
if !ok {
if c.HostKeyFallback != nil {
return c.HostKeyFallback(addr, remote, key)
}
return errors.New("ssh: non-certificate host key")
}
if cert.CertType != HostCert {
return fmt.Errorf("ssh: certificate presented as a host key has type %d", cert.CertType)
}
return c.CheckCert(addr, cert)
}
// Authenticate checks a user certificate. Authenticate can be used as
// a value for ServerConfig.PublicKeyCallback.
func (c *CertChecker) Authenticate(conn ConnMetadata, pubKey PublicKey) (*Permissions, error) {
cert, ok := pubKey.(*Certificate)
if !ok {
if c.UserKeyFallback != nil {
return c.UserKeyFallback(conn, pubKey)
}
return nil, errors.New("ssh: normal key pairs not accepted")
}
if cert.CertType != UserCert {
return nil, fmt.Errorf("ssh: cert has type %d", cert.CertType)
}
if err := c.CheckCert(conn.User(), cert); err != nil {
return nil, err
}
return &cert.Permissions, nil
}
// CheckCert checks CriticalOptions, ValidPrincipals, revocation, timestamp and
// the signature of the certificate.
func (c *CertChecker) CheckCert(principal string, cert *Certificate) error {
if c.IsRevoked != nil && c.IsRevoked(cert) {
return fmt.Errorf("ssh: certicate serial %d revoked", cert.Serial)
}
for opt, _ := range cert.CriticalOptions {
// sourceAddressCriticalOption will be enforced by
// serverAuthenticate
if opt == sourceAddressCriticalOption {
continue
}
found := false
for _, supp := range c.SupportedCriticalOptions {
if supp == opt {
found = true
break
}
}
if !found {
return fmt.Errorf("ssh: unsupported critical option %q in certificate", opt)
}
}
if len(cert.ValidPrincipals) > 0 {
// By default, certs are valid for all users/hosts.
found := false
for _, p := range cert.ValidPrincipals {
if p == principal {
found = true
break
}
}
if !found {
return fmt.Errorf("ssh: principal %q not in the set of valid principals for given certificate: %q", principal, cert.ValidPrincipals)
}
}
if !c.IsAuthority(cert.SignatureKey) {
return fmt.Errorf("ssh: certificate signed by unrecognized authority")
}
clock := c.Clock
if clock == nil {
clock = time.Now
}
unixNow := clock().Unix()
if after := int64(cert.ValidAfter); after < 0 || unixNow < int64(cert.ValidAfter) {
return fmt.Errorf("ssh: cert is not yet valid")
}
if before := int64(cert.ValidBefore); cert.ValidBefore != uint64(CertTimeInfinity) && (unixNow >= before || before < 0) {
return fmt.Errorf("ssh: cert has expired")
}
if err := cert.SignatureKey.Verify(cert.bytesForSigning(), cert.Signature); err != nil {
return fmt.Errorf("ssh: certificate signature does not verify")
}
return nil
}
// SignCert sets c.SignatureKey to the authority's public key and stores a
// Signature, by authority, in the certificate.
func (c *Certificate) SignCert(rand io.Reader, authority Signer) error {
c.Nonce = make([]byte, 32)
if _, err := io.ReadFull(rand, c.Nonce); err != nil {
return err
}
c.SignatureKey = authority.PublicKey()
sig, err := authority.Sign(rand, c.bytesForSigning())
if err != nil {
return err
}
c.Signature = sig
return nil
}
var certAlgoNames = map[string]string{
KeyAlgoRSA: CertAlgoRSAv01,
KeyAlgoDSA: CertAlgoDSAv01,
KeyAlgoECDSA256: CertAlgoECDSA256v01,
KeyAlgoECDSA384: CertAlgoECDSA384v01,
KeyAlgoECDSA521: CertAlgoECDSA521v01,
}
// certToPrivAlgo returns the underlying algorithm for a certificate algorithm.
// Panics if a non-certificate algorithm is passed.
func certToPrivAlgo(algo string) string {
for privAlgo, pubAlgo := range certAlgoNames {
if pubAlgo == algo {
return privAlgo
}
}
panic("unknown cert algorithm")
}
func (cert *Certificate) bytesForSigning() []byte {
c2 := *cert
c2.Signature = nil
out := c2.Marshal()
// Drop trailing signature length.
return out[:len(out)-4]
}
// Marshal serializes c into OpenSSH's wire format. It is part of the
// PublicKey interface.
func (c *Certificate) Marshal() []byte {
generic := genericCertData{
Serial: c.Serial,
CertType: c.CertType,
KeyId: c.KeyId,
ValidPrincipals: marshalStringList(c.ValidPrincipals),
ValidAfter: uint64(c.ValidAfter),
ValidBefore: uint64(c.ValidBefore),
CriticalOptions: marshalTuples(c.CriticalOptions),
Extensions: marshalTuples(c.Extensions),
Reserved: c.Reserved,
SignatureKey: c.SignatureKey.Marshal(),
}
if c.Signature != nil {
generic.Signature = Marshal(c.Signature)
}
genericBytes := Marshal(&generic)
keyBytes := c.Key.Marshal()
_, keyBytes, _ = parseString(keyBytes)
prefix := Marshal(&struct {
Name string
Nonce []byte
Key []byte `ssh:"rest"`
}{c.Type(), c.Nonce, keyBytes})
result := make([]byte, 0, len(prefix)+len(genericBytes))
result = append(result, prefix...)
result = append(result, genericBytes...)
return result
}
// Type returns the key name. It is part of the PublicKey interface.
func (c *Certificate) Type() string {
algo, ok := certAlgoNames[c.Key.Type()]
if !ok {
panic("unknown cert key type")
}
return algo
}
// Verify verifies a signature against the certificate's public
// key. It is part of the PublicKey interface.
func (c *Certificate) Verify(data []byte, sig *Signature) error {
return c.Key.Verify(data, sig)
}
func parseSignatureBody(in []byte) (out *Signature, rest []byte, ok bool) {
format, in, ok := parseString(in)
if !ok {
return
}
out = &Signature{
Format: string(format),
}
if out.Blob, in, ok = parseString(in); !ok {
return
}
return out, in, ok
}
func parseSignature(in []byte) (out *Signature, rest []byte, ok bool) {
sigBytes, rest, ok := parseString(in)
if !ok {
return
}
out, trailing, ok := parseSignatureBody(sigBytes)
if !ok || len(trailing) > 0 {
return nil, nil, false
}
return
}

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modules/crypto/ssh/certs_test.go
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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"bytes"
"crypto/rand"
"reflect"
"testing"
"time"
)
// Cert generated by ssh-keygen 6.0p1 Debian-4.
// % ssh-keygen -s ca-key -I test user-key
const exampleSSHCert = `ssh-rsa-cert-v01@openssh.com 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`
func TestParseCert(t *testing.T) {
authKeyBytes := []byte(exampleSSHCert)
key, _, _, rest, err := ParseAuthorizedKey(authKeyBytes)
if err != nil {
t.Fatalf("ParseAuthorizedKey: %v", err)
}
if len(rest) > 0 {
t.Errorf("rest: got %q, want empty", rest)
}
if _, ok := key.(*Certificate); !ok {
t.Fatalf("got %v (%T), want *Certificate", key, key)
}
marshaled := MarshalAuthorizedKey(key)
// Before comparison, remove the trailing newline that
// MarshalAuthorizedKey adds.
marshaled = marshaled[:len(marshaled)-1]
if !bytes.Equal(authKeyBytes, marshaled) {
t.Errorf("marshaled certificate does not match original: got %q, want %q", marshaled, authKeyBytes)
}
}
// Cert generated by ssh-keygen OpenSSH_6.8p1 OS X 10.10.3
// % ssh-keygen -s ca -I testcert -O source-address=192.168.1.0/24 -O force-command=/bin/sleep user.pub
// user.pub key: ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDACh1rt2DXfV3hk6fszSQcQ/rueMId0kVD9U7nl8cfEnFxqOCrNT92g4laQIGl2mn8lsGZfTLg8ksHq3gkvgO3oo/0wHy4v32JeBOHTsN5AL4gfHNEhWeWb50ev47hnTsRIt9P4dxogeUo/hTu7j9+s9lLpEQXCvq6xocXQt0j8MV9qZBBXFLXVT3cWIkSqOdwt/5ZBg+1GSrc7WfCXVWgTk4a20uPMuJPxU4RQwZW6X3+O8Pqo8C3cW0OzZRFP6gUYUKUsTI5WntlS+LAxgw1mZNsozFGdbiOPRnEryE3SRldh9vjDR3tin1fGpA5P7+CEB/bqaXtG3V+F2OkqaMN
// Critical Options:
// force-command /bin/sleep
// source-address 192.168.1.0/24
// Extensions:
// permit-X11-forwarding
// permit-agent-forwarding
// permit-port-forwarding
// permit-pty
// permit-user-rc
const exampleSSHCertWithOptions = `ssh-rsa-cert-v01@openssh.com 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`
func TestParseCertWithOptions(t *testing.T) {
opts := map[string]string{
"source-address": "192.168.1.0/24",
"force-command": "/bin/sleep",
}
exts := map[string]string{
"permit-X11-forwarding": "",
"permit-agent-forwarding": "",
"permit-port-forwarding": "",
"permit-pty": "",
"permit-user-rc": "",
}
authKeyBytes := []byte(exampleSSHCertWithOptions)
key, _, _, rest, err := ParseAuthorizedKey(authKeyBytes)
if err != nil {
t.Fatalf("ParseAuthorizedKey: %v", err)
}
if len(rest) > 0 {
t.Errorf("rest: got %q, want empty", rest)
}
cert, ok := key.(*Certificate)
if !ok {
t.Fatalf("got %v (%T), want *Certificate", key, key)
}
if !reflect.DeepEqual(cert.CriticalOptions, opts) {
t.Errorf("unexpected critical options - got %v, want %v", cert.CriticalOptions, opts)
}
if !reflect.DeepEqual(cert.Extensions, exts) {
t.Errorf("unexpected Extensions - got %v, want %v", cert.Extensions, exts)
}
marshaled := MarshalAuthorizedKey(key)
// Before comparison, remove the trailing newline that
// MarshalAuthorizedKey adds.
marshaled = marshaled[:len(marshaled)-1]
if !bytes.Equal(authKeyBytes, marshaled) {
t.Errorf("marshaled certificate does not match original: got %q, want %q", marshaled, authKeyBytes)
}
}
func TestValidateCert(t *testing.T) {
key, _, _, _, err := ParseAuthorizedKey([]byte(exampleSSHCert))
if err != nil {
t.Fatalf("ParseAuthorizedKey: %v", err)
}
validCert, ok := key.(*Certificate)
if !ok {
t.Fatalf("got %v (%T), want *Certificate", key, key)
}
checker := CertChecker{}
checker.IsAuthority = func(k PublicKey) bool {
return bytes.Equal(k.Marshal(), validCert.SignatureKey.Marshal())
}
if err := checker.CheckCert("user", validCert); err != nil {
t.Errorf("Unable to validate certificate: %v", err)
}
invalidCert := &Certificate{
Key: testPublicKeys["rsa"],
SignatureKey: testPublicKeys["ecdsa"],
ValidBefore: CertTimeInfinity,
Signature: &Signature{},
}
if err := checker.CheckCert("user", invalidCert); err == nil {
t.Error("Invalid cert signature passed validation")
}
}
func TestValidateCertTime(t *testing.T) {
cert := Certificate{
ValidPrincipals: []string{"user"},
Key: testPublicKeys["rsa"],
ValidAfter: 50,
ValidBefore: 100,
}
cert.SignCert(rand.Reader, testSigners["ecdsa"])
for ts, ok := range map[int64]bool{
25: false,
50: true,
99: true,
100: false,
125: false,
} {
checker := CertChecker{
Clock: func() time.Time { return time.Unix(ts, 0) },
}
checker.IsAuthority = func(k PublicKey) bool {
return bytes.Equal(k.Marshal(),
testPublicKeys["ecdsa"].Marshal())
}
if v := checker.CheckCert("user", &cert); (v == nil) != ok {
t.Errorf("Authenticate(%d): %v", ts, v)
}
}
}
// TODO(hanwen): tests for
//
// host keys:
// * fallbacks
func TestHostKeyCert(t *testing.T) {
cert := &Certificate{
ValidPrincipals: []string{"hostname", "hostname.domain"},
Key: testPublicKeys["rsa"],
ValidBefore: CertTimeInfinity,
CertType: HostCert,
}
cert.SignCert(rand.Reader, testSigners["ecdsa"])
checker := &CertChecker{
IsAuthority: func(p PublicKey) bool {
return bytes.Equal(testPublicKeys["ecdsa"].Marshal(), p.Marshal())
},
}
certSigner, err := NewCertSigner(cert, testSigners["rsa"])
if err != nil {
t.Errorf("NewCertSigner: %v", err)
}
for _, name := range []string{"hostname", "otherhost"} {
c1, c2, err := netPipe()
if err != nil {
t.Fatalf("netPipe: %v", err)
}
defer c1.Close()
defer c2.Close()
errc := make(chan error)
go func() {
conf := ServerConfig{
NoClientAuth: true,
}
conf.AddHostKey(certSigner)
_, _, _, err := NewServerConn(c1, &conf)
errc <- err
}()
config := &ClientConfig{
User: "user",
HostKeyCallback: checker.CheckHostKey,
}
_, _, _, err = NewClientConn(c2, name, config)
succeed := name == "hostname"
if (err == nil) != succeed {
t.Fatalf("NewClientConn(%q): %v", name, err)
}
err = <-errc
if (err == nil) != succeed {
t.Fatalf("NewServerConn(%q): %v", name, err)
}
}
}

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modules/crypto/ssh/channel.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"encoding/binary"
"errors"
"fmt"
"io"
"log"
"sync"
)
const (
minPacketLength = 9
// channelMaxPacket contains the maximum number of bytes that will be
// sent in a single packet. As per RFC 4253, section 6.1, 32k is also
// the minimum.
channelMaxPacket = 1 << 15
// We follow OpenSSH here.
channelWindowSize = 64 * channelMaxPacket
)
// NewChannel represents an incoming request to a channel. It must either be
// accepted for use by calling Accept, or rejected by calling Reject.
type NewChannel interface {
// Accept accepts the channel creation request. It returns the Channel
// and a Go channel containing SSH requests. The Go channel must be
// serviced otherwise the Channel will hang.
Accept() (Channel, <-chan *Request, error)
// Reject rejects the channel creation request. After calling
// this, no other methods on the Channel may be called.
Reject(reason RejectionReason, message string) error
// ChannelType returns the type of the channel, as supplied by the
// client.
ChannelType() string
// ExtraData returns the arbitrary payload for this channel, as supplied
// by the client. This data is specific to the channel type.
ExtraData() []byte
}
// A Channel is an ordered, reliable, flow-controlled, duplex stream
// that is multiplexed over an SSH connection.
type Channel interface {
// Read reads up to len(data) bytes from the channel.
Read(data []byte) (int, error)
// Write writes len(data) bytes to the channel.
Write(data []byte) (int, error)
// Close signals end of channel use. No data may be sent after this
// call.
Close() error
// CloseWrite signals the end of sending in-band
// data. Requests may still be sent, and the other side may
// still send data
CloseWrite() error
// SendRequest sends a channel request. If wantReply is true,
// it will wait for a reply and return the result as a
// boolean, otherwise the return value will be false. Channel
// requests are out-of-band messages so they may be sent even
// if the data stream is closed or blocked by flow control.
SendRequest(name string, wantReply bool, payload []byte) (bool, error)
// Stderr returns an io.ReadWriter that writes to this channel
// with the extended data type set to stderr. Stderr may
// safely be read and written from a different goroutine than
// Read and Write respectively.
Stderr() io.ReadWriter
}
// Request is a request sent outside of the normal stream of
// data. Requests can either be specific to an SSH channel, or they
// can be global.
type Request struct {
Type string
WantReply bool
Payload []byte
ch *channel
mux *mux
}
// Reply sends a response to a request. It must be called for all requests
// where WantReply is true and is a no-op otherwise. The payload argument is
// ignored for replies to channel-specific requests.
func (r *Request) Reply(ok bool, payload []byte) error {
if !r.WantReply {
return nil
}
if r.ch == nil {
return r.mux.ackRequest(ok, payload)
}
return r.ch.ackRequest(ok)
}
// RejectionReason is an enumeration used when rejecting channel creation
// requests. See RFC 4254, section 5.1.
type RejectionReason uint32
const (
Prohibited RejectionReason = iota + 1
ConnectionFailed
UnknownChannelType
ResourceShortage
)
// String converts the rejection reason to human readable form.
func (r RejectionReason) String() string {
switch r {
case Prohibited:
return "administratively prohibited"
case ConnectionFailed:
return "connect failed"
case UnknownChannelType:
return "unknown channel type"
case ResourceShortage:
return "resource shortage"
}
return fmt.Sprintf("unknown reason %d", int(r))
}
func min(a uint32, b int) uint32 {
if a < uint32(b) {
return a
}
return uint32(b)
}
type channelDirection uint8
const (
channelInbound channelDirection = iota
channelOutbound
)
// channel is an implementation of the Channel interface that works
// with the mux class.
type channel struct {
// R/O after creation
chanType string
extraData []byte
localId, remoteId uint32
// maxIncomingPayload and maxRemotePayload are the maximum
// payload sizes of normal and extended data packets for
// receiving and sending, respectively. The wire packet will
// be 9 or 13 bytes larger (excluding encryption overhead).
maxIncomingPayload uint32
maxRemotePayload uint32
mux *mux
// decided is set to true if an accept or reject message has been sent
// (for outbound channels) or received (for inbound channels).
decided bool
// direction contains either channelOutbound, for channels created
// locally, or channelInbound, for channels created by the peer.
direction channelDirection
// Pending internal channel messages.
msg chan interface{}
// Since requests have no ID, there can be only one request
// with WantReply=true outstanding. This lock is held by a
// goroutine that has such an outgoing request pending.
sentRequestMu sync.Mutex
incomingRequests chan *Request
sentEOF bool
// thread-safe data
remoteWin window
pending *buffer
extPending *buffer
// windowMu protects myWindow, the flow-control window.
windowMu sync.Mutex
myWindow uint32
// writeMu serializes calls to mux.conn.writePacket() and
// protects sentClose and packetPool. This mutex must be
// different from windowMu, as writePacket can block if there
// is a key exchange pending.
writeMu sync.Mutex
sentClose bool
// packetPool has a buffer for each extended channel ID to
// save allocations during writes.
packetPool map[uint32][]byte
}
// writePacket sends a packet. If the packet is a channel close, it updates
// sentClose. This method takes the lock c.writeMu.
func (c *channel) writePacket(packet []byte) error {
c.writeMu.Lock()
if c.sentClose {
c.writeMu.Unlock()
return io.EOF
}
c.sentClose = (packet[0] == msgChannelClose)
err := c.mux.conn.writePacket(packet)
c.writeMu.Unlock()
return err
}
func (c *channel) sendMessage(msg interface{}) error {
if debugMux {
log.Printf("send %d: %#v", c.mux.chanList.offset, msg)
}
p := Marshal(msg)
binary.BigEndian.PutUint32(p[1:], c.remoteId)
return c.writePacket(p)
}
// WriteExtended writes data to a specific extended stream. These streams are
// used, for example, for stderr.
func (c *channel) WriteExtended(data []byte, extendedCode uint32) (n int, err error) {
if c.sentEOF {
return 0, io.EOF
}
// 1 byte message type, 4 bytes remoteId, 4 bytes data length
opCode := byte(msgChannelData)
headerLength := uint32(9)
if extendedCode > 0 {
headerLength += 4
opCode = msgChannelExtendedData
}
c.writeMu.Lock()
packet := c.packetPool[extendedCode]
// We don't remove the buffer from packetPool, so
// WriteExtended calls from different goroutines will be
// flagged as errors by the race detector.
c.writeMu.Unlock()
for len(data) > 0 {
space := min(c.maxRemotePayload, len(data))
if space, err = c.remoteWin.reserve(space); err != nil {
return n, err
}
if want := headerLength + space; uint32(cap(packet)) < want {
packet = make([]byte, want)
} else {
packet = packet[:want]
}
todo := data[:space]
packet[0] = opCode
binary.BigEndian.PutUint32(packet[1:], c.remoteId)
if extendedCode > 0 {
binary.BigEndian.PutUint32(packet[5:], uint32(extendedCode))
}
binary.BigEndian.PutUint32(packet[headerLength-4:], uint32(len(todo)))
copy(packet[headerLength:], todo)
if err = c.writePacket(packet); err != nil {
return n, err
}
n += len(todo)
data = data[len(todo):]
}
c.writeMu.Lock()
c.packetPool[extendedCode] = packet
c.writeMu.Unlock()
return n, err
}
func (c *channel) handleData(packet []byte) error {
headerLen := 9
isExtendedData := packet[0] == msgChannelExtendedData
if isExtendedData {
headerLen = 13
}
if len(packet) < headerLen {
// malformed data packet
return parseError(packet[0])
}
var extended uint32
if isExtendedData {
extended = binary.BigEndian.Uint32(packet[5:])
}
length := binary.BigEndian.Uint32(packet[headerLen-4 : headerLen])
if length == 0 {
return nil
}
if length > c.maxIncomingPayload {
// TODO(hanwen): should send Disconnect?
return errors.New("ssh: incoming packet exceeds maximum payload size")
}
data := packet[headerLen:]
if length != uint32(len(data)) {
return errors.New("ssh: wrong packet length")
}
c.windowMu.Lock()
if c.myWindow < length {
c.windowMu.Unlock()
// TODO(hanwen): should send Disconnect with reason?
return errors.New("ssh: remote side wrote too much")
}
c.myWindow -= length
c.windowMu.Unlock()
if extended == 1 {
c.extPending.write(data)
} else if extended > 0 {
// discard other extended data.
} else {
c.pending.write(data)
}
return nil
}
func (c *channel) adjustWindow(n uint32) error {
c.windowMu.Lock()
// Since myWindow is managed on our side, and can never exceed
// the initial window setting, we don't worry about overflow.
c.myWindow += uint32(n)
c.windowMu.Unlock()
return c.sendMessage(windowAdjustMsg{
AdditionalBytes: uint32(n),
})
}
func (c *channel) ReadExtended(data []byte, extended uint32) (n int, err error) {
switch extended {
case 1:
n, err = c.extPending.Read(data)
case 0:
n, err = c.pending.Read(data)
default:
return 0, fmt.Errorf("ssh: extended code %d unimplemented", extended)
}
if n > 0 {
err = c.adjustWindow(uint32(n))
// sendWindowAdjust can return io.EOF if the remote
// peer has closed the connection, however we want to
// defer forwarding io.EOF to the caller of Read until
// the buffer has been drained.
if n > 0 && err == io.EOF {
err = nil
}
}
return n, err
}
func (c *channel) close() {
c.pending.eof()
c.extPending.eof()
close(c.msg)
close(c.incomingRequests)
c.writeMu.Lock()
// This is not necesary for a normal channel teardown, but if
// there was another error, it is.
c.sentClose = true
c.writeMu.Unlock()
// Unblock writers.
c.remoteWin.close()
}
// responseMessageReceived is called when a success or failure message is
// received on a channel to check that such a message is reasonable for the
// given channel.
func (c *channel) responseMessageReceived() error {
if c.direction == channelInbound {
return errors.New("ssh: channel response message received on inbound channel")
}
if c.decided {
return errors.New("ssh: duplicate response received for channel")
}
c.decided = true
return nil
}
func (c *channel) handlePacket(packet []byte) error {
switch packet[0] {
case msgChannelData, msgChannelExtendedData:
return c.handleData(packet)
case msgChannelClose:
c.sendMessage(channelCloseMsg{PeersId: c.remoteId})
c.mux.chanList.remove(c.localId)
c.close()
return nil
case msgChannelEOF:
// RFC 4254 is mute on how EOF affects dataExt messages but
// it is logical to signal EOF at the same time.
c.extPending.eof()
c.pending.eof()
return nil
}
decoded, err := decode(packet)
if err != nil {
return err
}
switch msg := decoded.(type) {
case *channelOpenFailureMsg:
if err := c.responseMessageReceived(); err != nil {
return err
}
c.mux.chanList.remove(msg.PeersId)
c.msg <- msg
case *channelOpenConfirmMsg:
if err := c.responseMessageReceived(); err != nil {
return err
}
if msg.MaxPacketSize < minPacketLength || msg.MaxPacketSize > 1<<31 {
return fmt.Errorf("ssh: invalid MaxPacketSize %d from peer", msg.MaxPacketSize)
}
c.remoteId = msg.MyId
c.maxRemotePayload = msg.MaxPacketSize
c.remoteWin.add(msg.MyWindow)
c.msg <- msg
case *windowAdjustMsg:
if !c.remoteWin.add(msg.AdditionalBytes) {
return fmt.Errorf("ssh: invalid window update for %d bytes", msg.AdditionalBytes)
}
case *channelRequestMsg:
req := Request{
Type: msg.Request,
WantReply: msg.WantReply,
Payload: msg.RequestSpecificData,
ch: c,
}
c.incomingRequests <- &req
default:
c.msg <- msg
}
return nil
}
func (m *mux) newChannel(chanType string, direction channelDirection, extraData []byte) *channel {
ch := &channel{
remoteWin: window{Cond: newCond()},
myWindow: channelWindowSize,
pending: newBuffer(),
extPending: newBuffer(),
direction: direction,
incomingRequests: make(chan *Request, 16),
msg: make(chan interface{}, 16),
chanType: chanType,
extraData: extraData,
mux: m,
packetPool: make(map[uint32][]byte),
}
ch.localId = m.chanList.add(ch)
return ch
}
var errUndecided = errors.New("ssh: must Accept or Reject channel")
var errDecidedAlready = errors.New("ssh: can call Accept or Reject only once")
type extChannel struct {
code uint32
ch *channel
}
func (e *extChannel) Write(data []byte) (n int, err error) {
return e.ch.WriteExtended(data, e.code)
}
func (e *extChannel) Read(data []byte) (n int, err error) {
return e.ch.ReadExtended(data, e.code)
}
func (c *channel) Accept() (Channel, <-chan *Request, error) {
if c.decided {
return nil, nil, errDecidedAlready
}
c.maxIncomingPayload = channelMaxPacket
confirm := channelOpenConfirmMsg{
PeersId: c.remoteId,
MyId: c.localId,
MyWindow: c.myWindow,
MaxPacketSize: c.maxIncomingPayload,
}
c.decided = true
if err := c.sendMessage(confirm); err != nil {
return nil, nil, err
}
return c, c.incomingRequests, nil
}
func (ch *channel) Reject(reason RejectionReason, message string) error {
if ch.decided {
return errDecidedAlready
}
reject := channelOpenFailureMsg{
PeersId: ch.remoteId,
Reason: reason,
Message: message,
Language: "en",
}
ch.decided = true
return ch.sendMessage(reject)
}
func (ch *channel) Read(data []byte) (int, error) {
if !ch.decided {
return 0, errUndecided
}
return ch.ReadExtended(data, 0)
}
func (ch *channel) Write(data []byte) (int, error) {
if !ch.decided {
return 0, errUndecided
}
return ch.WriteExtended(data, 0)
}
func (ch *channel) CloseWrite() error {
if !ch.decided {
return errUndecided
}
ch.sentEOF = true
return ch.sendMessage(channelEOFMsg{
PeersId: ch.remoteId})
}
func (ch *channel) Close() error {
if !ch.decided {
return errUndecided
}
return ch.sendMessage(channelCloseMsg{
PeersId: ch.remoteId})
}
// Extended returns an io.ReadWriter that sends and receives data on the given,
// SSH extended stream. Such streams are used, for example, for stderr.
func (ch *channel) Extended(code uint32) io.ReadWriter {
if !ch.decided {
return nil
}
return &extChannel{code, ch}
}
func (ch *channel) Stderr() io.ReadWriter {
return ch.Extended(1)
}
func (ch *channel) SendRequest(name string, wantReply bool, payload []byte) (bool, error) {
if !ch.decided {
return false, errUndecided
}
if wantReply {
ch.sentRequestMu.Lock()
defer ch.sentRequestMu.Unlock()
}
msg := channelRequestMsg{
PeersId: ch.remoteId,
Request: name,
WantReply: wantReply,
RequestSpecificData: payload,
}
if err := ch.sendMessage(msg); err != nil {
return false, err
}
if wantReply {
m, ok := (<-ch.msg)
if !ok {
return false, io.EOF
}
switch m.(type) {
case *channelRequestFailureMsg:
return false, nil
case *channelRequestSuccessMsg:
return true, nil
default:
return false, fmt.Errorf("ssh: unexpected response to channel request: %#v", m)
}
}
return false, nil
}
// ackRequest either sends an ack or nack to the channel request.
func (ch *channel) ackRequest(ok bool) error {
if !ch.decided {
return errUndecided
}
var msg interface{}
if !ok {
msg = channelRequestFailureMsg{
PeersId: ch.remoteId,
}
} else {
msg = channelRequestSuccessMsg{
PeersId: ch.remoteId,
}
}
return ch.sendMessage(msg)
}
func (ch *channel) ChannelType() string {
return ch.chanType
}
func (ch *channel) ExtraData() []byte {
return ch.extraData
}

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modules/crypto/ssh/cipher.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"crypto/aes"
"crypto/cipher"
"crypto/rc4"
"crypto/subtle"
"encoding/binary"
"errors"
"fmt"
"hash"
"io"
"io/ioutil"
)
const (
packetSizeMultiple = 16 // TODO(huin) this should be determined by the cipher.
// RFC 4253 section 6.1 defines a minimum packet size of 32768 that implementations
// MUST be able to process (plus a few more kilobytes for padding and mac). The RFC
// indicates implementations SHOULD be able to handle larger packet sizes, but then
// waffles on about reasonable limits.
//
// OpenSSH caps their maxPacket at 256kB so we choose to do
// the same. maxPacket is also used to ensure that uint32
// length fields do not overflow, so it should remain well
// below 4G.
maxPacket = 256 * 1024
)
// noneCipher implements cipher.Stream and provides no encryption. It is used
// by the transport before the first key-exchange.
type noneCipher struct{}
func (c noneCipher) XORKeyStream(dst, src []byte) {
copy(dst, src)
}
func newAESCTR(key, iv []byte) (cipher.Stream, error) {
c, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
return cipher.NewCTR(c, iv), nil
}
func newRC4(key, iv []byte) (cipher.Stream, error) {
return rc4.NewCipher(key)
}
type streamCipherMode struct {
keySize int
ivSize int
skip int
createFunc func(key, iv []byte) (cipher.Stream, error)
}
func (c *streamCipherMode) createStream(key, iv []byte) (cipher.Stream, error) {
if len(key) < c.keySize {
panic("ssh: key length too small for cipher")
}
if len(iv) < c.ivSize {
panic("ssh: iv too small for cipher")
}
stream, err := c.createFunc(key[:c.keySize], iv[:c.ivSize])
if err != nil {
return nil, err
}
var streamDump []byte
if c.skip > 0 {
streamDump = make([]byte, 512)
}
for remainingToDump := c.skip; remainingToDump > 0; {
dumpThisTime := remainingToDump
if dumpThisTime > len(streamDump) {
dumpThisTime = len(streamDump)
}
stream.XORKeyStream(streamDump[:dumpThisTime], streamDump[:dumpThisTime])
remainingToDump -= dumpThisTime
}
return stream, nil
}
// cipherModes documents properties of supported ciphers. Ciphers not included
// are not supported and will not be negotiated, even if explicitly requested in
// ClientConfig.Crypto.Ciphers.
var cipherModes = map[string]*streamCipherMode{
// Ciphers from RFC4344, which introduced many CTR-based ciphers. Algorithms
// are defined in the order specified in the RFC.
"aes128-ctr": {16, aes.BlockSize, 0, newAESCTR},
"aes192-ctr": {24, aes.BlockSize, 0, newAESCTR},
"aes256-ctr": {32, aes.BlockSize, 0, newAESCTR},
// Ciphers from RFC4345, which introduces security-improved arcfour ciphers.
// They are defined in the order specified in the RFC.
"arcfour128": {16, 0, 1536, newRC4},
"arcfour256": {32, 0, 1536, newRC4},
// Cipher defined in RFC 4253, which describes SSH Transport Layer Protocol.
// Note that this cipher is not safe, as stated in RFC 4253: "Arcfour (and
// RC4) has problems with weak keys, and should be used with caution."
// RFC4345 introduces improved versions of Arcfour.
"arcfour": {16, 0, 0, newRC4},
// AES-GCM is not a stream cipher, so it is constructed with a
// special case. If we add any more non-stream ciphers, we
// should invest a cleaner way to do this.
gcmCipherID: {16, 12, 0, nil},
// insecure cipher, see http://www.isg.rhul.ac.uk/~kp/SandPfinal.pdf
// uncomment below to enable it.
// aes128cbcID: {16, aes.BlockSize, 0, nil},
}
// prefixLen is the length of the packet prefix that contains the packet length
// and number of padding bytes.
const prefixLen = 5
// streamPacketCipher is a packetCipher using a stream cipher.
type streamPacketCipher struct {
mac hash.Hash
cipher cipher.Stream
// The following members are to avoid per-packet allocations.
prefix [prefixLen]byte
seqNumBytes [4]byte
padding [2 * packetSizeMultiple]byte
packetData []byte
macResult []byte
}
// readPacket reads and decrypt a single packet from the reader argument.
func (s *streamPacketCipher) readPacket(seqNum uint32, r io.Reader) ([]byte, error) {
if _, err := io.ReadFull(r, s.prefix[:]); err != nil {
return nil, err
}
s.cipher.XORKeyStream(s.prefix[:], s.prefix[:])
length := binary.BigEndian.Uint32(s.prefix[0:4])
paddingLength := uint32(s.prefix[4])
var macSize uint32
if s.mac != nil {
s.mac.Reset()
binary.BigEndian.PutUint32(s.seqNumBytes[:], seqNum)
s.mac.Write(s.seqNumBytes[:])
s.mac.Write(s.prefix[:])
macSize = uint32(s.mac.Size())
}
if length <= paddingLength+1 {
return nil, errors.New("ssh: invalid packet length, packet too small")
}
if length > maxPacket {
return nil, errors.New("ssh: invalid packet length, packet too large")
}
// the maxPacket check above ensures that length-1+macSize
// does not overflow.
if uint32(cap(s.packetData)) < length-1+macSize {
s.packetData = make([]byte, length-1+macSize)
} else {
s.packetData = s.packetData[:length-1+macSize]
}
if _, err := io.ReadFull(r, s.packetData); err != nil {
return nil, err
}
mac := s.packetData[length-1:]
data := s.packetData[:length-1]
s.cipher.XORKeyStream(data, data)
if s.mac != nil {
s.mac.Write(data)
s.macResult = s.mac.Sum(s.macResult[:0])
if subtle.ConstantTimeCompare(s.macResult, mac) != 1 {
return nil, errors.New("ssh: MAC failure")
}
}
return s.packetData[:length-paddingLength-1], nil
}
// writePacket encrypts and sends a packet of data to the writer argument
func (s *streamPacketCipher) writePacket(seqNum uint32, w io.Writer, rand io.Reader, packet []byte) error {
if len(packet) > maxPacket {
return errors.New("ssh: packet too large")
}
paddingLength := packetSizeMultiple - (prefixLen+len(packet))%packetSizeMultiple
if paddingLength < 4 {
paddingLength += packetSizeMultiple
}
length := len(packet) + 1 + paddingLength
binary.BigEndian.PutUint32(s.prefix[:], uint32(length))
s.prefix[4] = byte(paddingLength)
padding := s.padding[:paddingLength]
if _, err := io.ReadFull(rand, padding); err != nil {
return err
}
if s.mac != nil {
s.mac.Reset()
binary.BigEndian.PutUint32(s.seqNumBytes[:], seqNum)
s.mac.Write(s.seqNumBytes[:])
s.mac.Write(s.prefix[:])
s.mac.Write(packet)
s.mac.Write(padding)
}
s.cipher.XORKeyStream(s.prefix[:], s.prefix[:])
s.cipher.XORKeyStream(packet, packet)
s.cipher.XORKeyStream(padding, padding)
if _, err := w.Write(s.prefix[:]); err != nil {
return err
}
if _, err := w.Write(packet); err != nil {
return err
}
if _, err := w.Write(padding); err != nil {
return err
}
if s.mac != nil {
s.macResult = s.mac.Sum(s.macResult[:0])
if _, err := w.Write(s.macResult); err != nil {
return err
}
}
return nil
}
type gcmCipher struct {
aead cipher.AEAD
prefix [4]byte
iv []byte
buf []byte
}
func newGCMCipher(iv, key, macKey []byte) (packetCipher, error) {
c, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
aead, err := cipher.NewGCM(c)
if err != nil {
return nil, err
}
return &gcmCipher{
aead: aead,
iv: iv,
}, nil
}
const gcmTagSize = 16
func (c *gcmCipher) writePacket(seqNum uint32, w io.Writer, rand io.Reader, packet []byte) error {
// Pad out to multiple of 16 bytes. This is different from the
// stream cipher because that encrypts the length too.
padding := byte(packetSizeMultiple - (1+len(packet))%packetSizeMultiple)
if padding < 4 {
padding += packetSizeMultiple
}
length := uint32(len(packet) + int(padding) + 1)
binary.BigEndian.PutUint32(c.prefix[:], length)
if _, err := w.Write(c.prefix[:]); err != nil {
return err
}
if cap(c.buf) < int(length) {
c.buf = make([]byte, length)
} else {
c.buf = c.buf[:length]
}
c.buf[0] = padding
copy(c.buf[1:], packet)
if _, err := io.ReadFull(rand, c.buf[1+len(packet):]); err != nil {
return err
}
c.buf = c.aead.Seal(c.buf[:0], c.iv, c.buf, c.prefix[:])
if _, err := w.Write(c.buf); err != nil {
return err
}
c.incIV()
return nil
}
func (c *gcmCipher) incIV() {
for i := 4 + 7; i >= 4; i-- {
c.iv[i]++
if c.iv[i] != 0 {
break
}
}
}
func (c *gcmCipher) readPacket(seqNum uint32, r io.Reader) ([]byte, error) {
if _, err := io.ReadFull(r, c.prefix[:]); err != nil {
return nil, err
}
length := binary.BigEndian.Uint32(c.prefix[:])
if length > maxPacket {
return nil, errors.New("ssh: max packet length exceeded.")
}
if cap(c.buf) < int(length+gcmTagSize) {
c.buf = make([]byte, length+gcmTagSize)
} else {
c.buf = c.buf[:length+gcmTagSize]
}
if _, err := io.ReadFull(r, c.buf); err != nil {
return nil, err
}
plain, err := c.aead.Open(c.buf[:0], c.iv, c.buf, c.prefix[:])
if err != nil {
return nil, err
}
c.incIV()
padding := plain[0]
if padding < 4 || padding >= 20 {
return nil, fmt.Errorf("ssh: illegal padding %d", padding)
}
if int(padding+1) >= len(plain) {
return nil, fmt.Errorf("ssh: padding %d too large", padding)
}
plain = plain[1 : length-uint32(padding)]
return plain, nil
}
// cbcCipher implements aes128-cbc cipher defined in RFC 4253 section 6.1
type cbcCipher struct {
mac hash.Hash
macSize uint32
decrypter cipher.BlockMode
encrypter cipher.BlockMode
// The following members are to avoid per-packet allocations.
seqNumBytes [4]byte
packetData []byte
macResult []byte
// Amount of data we should still read to hide which
// verification error triggered.
oracleCamouflage uint32
}
func newAESCBCCipher(iv, key, macKey []byte, algs directionAlgorithms) (packetCipher, error) {
c, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
cbc := &cbcCipher{
mac: macModes[algs.MAC].new(macKey),
decrypter: cipher.NewCBCDecrypter(c, iv),
encrypter: cipher.NewCBCEncrypter(c, iv),
packetData: make([]byte, 1024),
}
if cbc.mac != nil {
cbc.macSize = uint32(cbc.mac.Size())
}
return cbc, nil
}
func maxUInt32(a, b int) uint32 {
if a > b {
return uint32(a)
}
return uint32(b)
}
const (
cbcMinPacketSizeMultiple = 8
cbcMinPacketSize = 16
cbcMinPaddingSize = 4
)
// cbcError represents a verification error that may leak information.
type cbcError string
func (e cbcError) Error() string { return string(e) }
func (c *cbcCipher) readPacket(seqNum uint32, r io.Reader) ([]byte, error) {
p, err := c.readPacketLeaky(seqNum, r)
if err != nil {
if _, ok := err.(cbcError); ok {
// Verification error: read a fixed amount of
// data, to make distinguishing between
// failing MAC and failing length check more
// difficult.
io.CopyN(ioutil.Discard, r, int64(c.oracleCamouflage))
}
}
return p, err
}
func (c *cbcCipher) readPacketLeaky(seqNum uint32, r io.Reader) ([]byte, error) {
blockSize := c.decrypter.BlockSize()
// Read the header, which will include some of the subsequent data in the
// case of block ciphers - this is copied back to the payload later.
// How many bytes of payload/padding will be read with this first read.
firstBlockLength := uint32((prefixLen + blockSize - 1) / blockSize * blockSize)
firstBlock := c.packetData[:firstBlockLength]
if _, err := io.ReadFull(r, firstBlock); err != nil {
return nil, err
}
c.oracleCamouflage = maxPacket + 4 + c.macSize - firstBlockLength
c.decrypter.CryptBlocks(firstBlock, firstBlock)
length := binary.BigEndian.Uint32(firstBlock[:4])
if length > maxPacket {
return nil, cbcError("ssh: packet too large")
}
if length+4 < maxUInt32(cbcMinPacketSize, blockSize) {
// The minimum size of a packet is 16 (or the cipher block size, whichever
// is larger) bytes.
return nil, cbcError("ssh: packet too small")
}
// The length of the packet (including the length field but not the MAC) must
// be a multiple of the block size or 8, whichever is larger.
if (length+4)%maxUInt32(cbcMinPacketSizeMultiple, blockSize) != 0 {
return nil, cbcError("ssh: invalid packet length multiple")
}
paddingLength := uint32(firstBlock[4])
if paddingLength < cbcMinPaddingSize || length <= paddingLength+1 {
return nil, cbcError("ssh: invalid packet length")
}
// Positions within the c.packetData buffer:
macStart := 4 + length
paddingStart := macStart - paddingLength
// Entire packet size, starting before length, ending at end of mac.
entirePacketSize := macStart + c.macSize
// Ensure c.packetData is large enough for the entire packet data.
if uint32(cap(c.packetData)) < entirePacketSize {
// Still need to upsize and copy, but this should be rare at runtime, only
// on upsizing the packetData buffer.
c.packetData = make([]byte, entirePacketSize)
copy(c.packetData, firstBlock)
} else {
c.packetData = c.packetData[:entirePacketSize]
}
if n, err := io.ReadFull(r, c.packetData[firstBlockLength:]); err != nil {
return nil, err
} else {
c.oracleCamouflage -= uint32(n)
}
remainingCrypted := c.packetData[firstBlockLength:macStart]
c.decrypter.CryptBlocks(remainingCrypted, remainingCrypted)
mac := c.packetData[macStart:]
if c.mac != nil {
c.mac.Reset()
binary.BigEndian.PutUint32(c.seqNumBytes[:], seqNum)
c.mac.Write(c.seqNumBytes[:])
c.mac.Write(c.packetData[:macStart])
c.macResult = c.mac.Sum(c.macResult[:0])
if subtle.ConstantTimeCompare(c.macResult, mac) != 1 {
return nil, cbcError("ssh: MAC failure")
}
}
return c.packetData[prefixLen:paddingStart], nil
}
func (c *cbcCipher) writePacket(seqNum uint32, w io.Writer, rand io.Reader, packet []byte) error {
effectiveBlockSize := maxUInt32(cbcMinPacketSizeMultiple, c.encrypter.BlockSize())
// Length of encrypted portion of the packet (header, payload, padding).
// Enforce minimum padding and packet size.
encLength := maxUInt32(prefixLen+len(packet)+cbcMinPaddingSize, cbcMinPaddingSize)
// Enforce block size.
encLength = (encLength + effectiveBlockSize - 1) / effectiveBlockSize * effectiveBlockSize
length := encLength - 4
paddingLength := int(length) - (1 + len(packet))
// Overall buffer contains: header, payload, padding, mac.
// Space for the MAC is reserved in the capacity but not the slice length.
bufferSize := encLength + c.macSize
if uint32(cap(c.packetData)) < bufferSize {
c.packetData = make([]byte, encLength, bufferSize)
} else {
c.packetData = c.packetData[:encLength]
}
p := c.packetData
// Packet header.
binary.BigEndian.PutUint32(p, length)
p = p[4:]
p[0] = byte(paddingLength)
// Payload.
p = p[1:]
copy(p, packet)
// Padding.
p = p[len(packet):]
if _, err := io.ReadFull(rand, p); err != nil {
return err
}
if c.mac != nil {
c.mac.Reset()
binary.BigEndian.PutUint32(c.seqNumBytes[:], seqNum)
c.mac.Write(c.seqNumBytes[:])
c.mac.Write(c.packetData)
// The MAC is now appended into the capacity reserved for it earlier.
c.packetData = c.mac.Sum(c.packetData)
}
c.encrypter.CryptBlocks(c.packetData[:encLength], c.packetData[:encLength])
if _, err := w.Write(c.packetData); err != nil {
return err
}
return nil
}

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modules/crypto/ssh/cipher_test.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"bytes"
"crypto"
"crypto/aes"
"crypto/rand"
"testing"
)
func TestDefaultCiphersExist(t *testing.T) {
for _, cipherAlgo := range supportedCiphers {
if _, ok := cipherModes[cipherAlgo]; !ok {
t.Errorf("default cipher %q is unknown", cipherAlgo)
}
}
}
func TestPacketCiphers(t *testing.T) {
// Still test aes128cbc cipher althought it's commented out.
cipherModes[aes128cbcID] = &streamCipherMode{16, aes.BlockSize, 0, nil}
defer delete(cipherModes, aes128cbcID)
for cipher := range cipherModes {
kr := &kexResult{Hash: crypto.SHA1}
algs := directionAlgorithms{
Cipher: cipher,
MAC: "hmac-sha1",
Compression: "none",
}
client, err := newPacketCipher(clientKeys, algs, kr)
if err != nil {
t.Errorf("newPacketCipher(client, %q): %v", cipher, err)
continue
}
server, err := newPacketCipher(clientKeys, algs, kr)
if err != nil {
t.Errorf("newPacketCipher(client, %q): %v", cipher, err)
continue
}
want := "bla bla"
input := []byte(want)
buf := &bytes.Buffer{}
if err := client.writePacket(0, buf, rand.Reader, input); err != nil {
t.Errorf("writePacket(%q): %v", cipher, err)
continue
}
packet, err := server.readPacket(0, buf)
if err != nil {
t.Errorf("readPacket(%q): %v", cipher, err)
continue
}
if string(packet) != want {
t.Errorf("roundtrip(%q): got %q, want %q", cipher, packet, want)
}
}
}
func TestCBCOracleCounterMeasure(t *testing.T) {
cipherModes[aes128cbcID] = &streamCipherMode{16, aes.BlockSize, 0, nil}
defer delete(cipherModes, aes128cbcID)
kr := &kexResult{Hash: crypto.SHA1}
algs := directionAlgorithms{
Cipher: aes128cbcID,
MAC: "hmac-sha1",
Compression: "none",
}
client, err := newPacketCipher(clientKeys, algs, kr)
if err != nil {
t.Fatalf("newPacketCipher(client): %v", err)
}
want := "bla bla"
input := []byte(want)
buf := &bytes.Buffer{}
if err := client.writePacket(0, buf, rand.Reader, input); err != nil {
t.Errorf("writePacket: %v", err)
}
packetSize := buf.Len()
buf.Write(make([]byte, 2*maxPacket))
// We corrupt each byte, but this usually will only test the
// 'packet too large' or 'MAC failure' cases.
lastRead := -1
for i := 0; i < packetSize; i++ {
server, err := newPacketCipher(clientKeys, algs, kr)
if err != nil {
t.Fatalf("newPacketCipher(client): %v", err)
}
fresh := &bytes.Buffer{}
fresh.Write(buf.Bytes())
fresh.Bytes()[i] ^= 0x01
before := fresh.Len()
_, err = server.readPacket(0, fresh)
if err == nil {
t.Errorf("corrupt byte %d: readPacket succeeded ", i)
continue
}
if _, ok := err.(cbcError); !ok {
t.Errorf("corrupt byte %d: got %v (%T), want cbcError", i, err, err)
continue
}
after := fresh.Len()
bytesRead := before - after
if bytesRead < maxPacket {
t.Errorf("corrupt byte %d: read %d bytes, want more than %d", i, bytesRead, maxPacket)
continue
}
if i > 0 && bytesRead != lastRead {
t.Errorf("corrupt byte %d: read %d bytes, want %d bytes read", i, bytesRead, lastRead)
}
lastRead = bytesRead
}
}

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modules/crypto/ssh/client.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"errors"
"fmt"
"net"
"sync"
)
// Client implements a traditional SSH client that supports shells,
// subprocesses, port forwarding and tunneled dialing.
type Client struct {
Conn
forwards forwardList // forwarded tcpip connections from the remote side
mu sync.Mutex
channelHandlers map[string]chan NewChannel
}
// HandleChannelOpen returns a channel on which NewChannel requests
// for the given type are sent. If the type already is being handled,
// nil is returned. The channel is closed when the connection is closed.
func (c *Client) HandleChannelOpen(channelType string) <-chan NewChannel {
c.mu.Lock()
defer c.mu.Unlock()
if c.channelHandlers == nil {
// The SSH channel has been closed.
c := make(chan NewChannel)
close(c)
return c
}
ch := c.channelHandlers[channelType]
if ch != nil {
return nil
}
ch = make(chan NewChannel, 16)
c.channelHandlers[channelType] = ch
return ch
}
// NewClient creates a Client on top of the given connection.
func NewClient(c Conn, chans <-chan NewChannel, reqs <-chan *Request) *Client {
conn := &Client{
Conn: c,
channelHandlers: make(map[string]chan NewChannel, 1),
}
go conn.handleGlobalRequests(reqs)
go conn.handleChannelOpens(chans)
go func() {
conn.Wait()
conn.forwards.closeAll()
}()
go conn.forwards.handleChannels(conn.HandleChannelOpen("forwarded-tcpip"))
return conn
}
// NewClientConn establishes an authenticated SSH connection using c
// as the underlying transport. The Request and NewChannel channels
// must be serviced or the connection will hang.
func NewClientConn(c net.Conn, addr string, config *ClientConfig) (Conn, <-chan NewChannel, <-chan *Request, error) {
fullConf := *config
fullConf.SetDefaults()
conn := &connection{
sshConn: sshConn{conn: c},
}
if err := conn.clientHandshake(addr, &fullConf); err != nil {
c.Close()
return nil, nil, nil, fmt.Errorf("ssh: handshake failed: %v", err)
}
conn.mux = newMux(conn.transport)
return conn, conn.mux.incomingChannels, conn.mux.incomingRequests, nil
}
// clientHandshake performs the client side key exchange. See RFC 4253 Section
// 7.
func (c *connection) clientHandshake(dialAddress string, config *ClientConfig) error {
if config.ClientVersion != "" {
c.clientVersion = []byte(config.ClientVersion)
} else {
c.clientVersion = []byte(packageVersion)
}
var err error
c.serverVersion, err = exchangeVersions(c.sshConn.conn, c.clientVersion)
if err != nil {
return err
}
c.transport = newClientTransport(
newTransport(c.sshConn.conn, config.Rand, true /* is client */),
c.clientVersion, c.serverVersion, config, dialAddress, c.sshConn.RemoteAddr())
if err := c.transport.requestKeyChange(); err != nil {
return err
}
if packet, err := c.transport.readPacket(); err != nil {
return err
} else if packet[0] != msgNewKeys {
return unexpectedMessageError(msgNewKeys, packet[0])
}
// We just did the key change, so the session ID is established.
c.sessionID = c.transport.getSessionID()
return c.clientAuthenticate(config)
}
// verifyHostKeySignature verifies the host key obtained in the key
// exchange.
func verifyHostKeySignature(hostKey PublicKey, result *kexResult) error {
sig, rest, ok := parseSignatureBody(result.Signature)
if len(rest) > 0 || !ok {
return errors.New("ssh: signature parse error")
}
return hostKey.Verify(result.H, sig)
}
// NewSession opens a new Session for this client. (A session is a remote
// execution of a program.)
func (c *Client) NewSession() (*Session, error) {
ch, in, err := c.OpenChannel("session", nil)
if err != nil {
return nil, err
}
return newSession(ch, in)
}
func (c *Client) handleGlobalRequests(incoming <-chan *Request) {
for r := range incoming {
// This handles keepalive messages and matches
// the behaviour of OpenSSH.
r.Reply(false, nil)
}
}
// handleChannelOpens channel open messages from the remote side.
func (c *Client) handleChannelOpens(in <-chan NewChannel) {
for ch := range in {
c.mu.Lock()
handler := c.channelHandlers[ch.ChannelType()]
c.mu.Unlock()
if handler != nil {
handler <- ch
} else {
ch.Reject(UnknownChannelType, fmt.Sprintf("unknown channel type: %v", ch.ChannelType()))
}
}
c.mu.Lock()
for _, ch := range c.channelHandlers {
close(ch)
}
c.channelHandlers = nil
c.mu.Unlock()
}
// Dial starts a client connection to the given SSH server. It is a
// convenience function that connects to the given network address,
// initiates the SSH handshake, and then sets up a Client. For access
// to incoming channels and requests, use net.Dial with NewClientConn
// instead.
func Dial(network, addr string, config *ClientConfig) (*Client, error) {
conn, err := net.Dial(network, addr)
if err != nil {
return nil, err
}
c, chans, reqs, err := NewClientConn(conn, addr, config)
if err != nil {
return nil, err
}
return NewClient(c, chans, reqs), nil
}
// A ClientConfig structure is used to configure a Client. It must not be
// modified after having been passed to an SSH function.
type ClientConfig struct {
// Config contains configuration that is shared between clients and
// servers.
Config
// User contains the username to authenticate as.
User string
// Auth contains possible authentication methods to use with the
// server. Only the first instance of a particular RFC 4252 method will
// be used during authentication.
Auth []AuthMethod
// HostKeyCallback, if not nil, is called during the cryptographic
// handshake to validate the server's host key. A nil HostKeyCallback
// implies that all host keys are accepted.
HostKeyCallback func(hostname string, remote net.Addr, key PublicKey) error
// ClientVersion contains the version identification string that will
// be used for the connection. If empty, a reasonable default is used.
ClientVersion string
// HostKeyAlgorithms lists the key types that the client will
// accept from the server as host key, in order of
// preference. If empty, a reasonable default is used. Any
// string returned from PublicKey.Type method may be used, or
// any of the CertAlgoXxxx and KeyAlgoXxxx constants.
HostKeyAlgorithms []string
}

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modules/crypto/ssh/client_auth.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"bytes"
"errors"
"fmt"
"io"
)
// clientAuthenticate authenticates with the remote server. See RFC 4252.
func (c *connection) clientAuthenticate(config *ClientConfig) error {
// initiate user auth session
if err := c.transport.writePacket(Marshal(&serviceRequestMsg{serviceUserAuth})); err != nil {
return err
}
packet, err := c.transport.readPacket()
if err != nil {
return err
}
var serviceAccept serviceAcceptMsg
if err := Unmarshal(packet, &serviceAccept); err != nil {
return err
}
// during the authentication phase the client first attempts the "none" method
// then any untried methods suggested by the server.
tried := make(map[string]bool)
var lastMethods []string
for auth := AuthMethod(new(noneAuth)); auth != nil; {
ok, methods, err := auth.auth(c.transport.getSessionID(), config.User, c.transport, config.Rand)
if err != nil {
return err
}
if ok {
// success
return nil
}
tried[auth.method()] = true
if methods == nil {
methods = lastMethods
}
lastMethods = methods
auth = nil
findNext:
for _, a := range config.Auth {
candidateMethod := a.method()
if tried[candidateMethod] {
continue
}
for _, meth := range methods {
if meth == candidateMethod {
auth = a
break findNext
}
}
}
}
return fmt.Errorf("ssh: unable to authenticate, attempted methods %v, no supported methods remain", keys(tried))
}
func keys(m map[string]bool) []string {
s := make([]string, 0, len(m))
for key := range m {
s = append(s, key)
}
return s
}
// An AuthMethod represents an instance of an RFC 4252 authentication method.
type AuthMethod interface {
// auth authenticates user over transport t.
// Returns true if authentication is successful.
// If authentication is not successful, a []string of alternative
// method names is returned. If the slice is nil, it will be ignored
// and the previous set of possible methods will be reused.
auth(session []byte, user string, p packetConn, rand io.Reader) (bool, []string, error)
// method returns the RFC 4252 method name.
method() string
}
// "none" authentication, RFC 4252 section 5.2.
type noneAuth int
func (n *noneAuth) auth(session []byte, user string, c packetConn, rand io.Reader) (bool, []string, error) {
if err := c.writePacket(Marshal(&userAuthRequestMsg{
User: user,
Service: serviceSSH,
Method: "none",
})); err != nil {
return false, nil, err
}
return handleAuthResponse(c)
}
func (n *noneAuth) method() string {
return "none"
}
// passwordCallback is an AuthMethod that fetches the password through
// a function call, e.g. by prompting the user.
type passwordCallback func() (password string, err error)
func (cb passwordCallback) auth(session []byte, user string, c packetConn, rand io.Reader) (bool, []string, error) {
type passwordAuthMsg struct {
User string `sshtype:"50"`
Service string
Method string
Reply bool
Password string
}
pw, err := cb()
// REVIEW NOTE: is there a need to support skipping a password attempt?
// The program may only find out that the user doesn't have a password
// when prompting.
if err != nil {
return false, nil, err
}
if err := c.writePacket(Marshal(&passwordAuthMsg{
User: user,
Service: serviceSSH,
Method: cb.method(),
Reply: false,
Password: pw,
})); err != nil {
return false, nil, err
}
return handleAuthResponse(c)
}
func (cb passwordCallback) method() string {
return "password"
}
// Password returns an AuthMethod using the given password.
func Password(secret string) AuthMethod {
return passwordCallback(func() (string, error) { return secret, nil })
}
// PasswordCallback returns an AuthMethod that uses a callback for
// fetching a password.
func PasswordCallback(prompt func() (secret string, err error)) AuthMethod {
return passwordCallback(prompt)
}
type publickeyAuthMsg struct {
User string `sshtype:"50"`
Service string
Method string
// HasSig indicates to the receiver packet that the auth request is signed and
// should be used for authentication of the request.
HasSig bool
Algoname string
PubKey []byte
// Sig is tagged with "rest" so Marshal will exclude it during
// validateKey
Sig []byte `ssh:"rest"`
}
// publicKeyCallback is an AuthMethod that uses a set of key
// pairs for authentication.
type publicKeyCallback func() ([]Signer, error)
func (cb publicKeyCallback) method() string {
return "publickey"
}
func (cb publicKeyCallback) auth(session []byte, user string, c packetConn, rand io.Reader) (bool, []string, error) {
// Authentication is performed in two stages. The first stage sends an
// enquiry to test if each key is acceptable to the remote. The second
// stage attempts to authenticate with the valid keys obtained in the
// first stage.
signers, err := cb()
if err != nil {
return false, nil, err
}
var validKeys []Signer
for _, signer := range signers {
if ok, err := validateKey(signer.PublicKey(), user, c); ok {
validKeys = append(validKeys, signer)
} else {
if err != nil {
return false, nil, err
}
}
}
// methods that may continue if this auth is not successful.
var methods []string
for _, signer := range validKeys {
pub := signer.PublicKey()
pubKey := pub.Marshal()
sign, err := signer.Sign(rand, buildDataSignedForAuth(session, userAuthRequestMsg{
User: user,
Service: serviceSSH,
Method: cb.method(),
}, []byte(pub.Type()), pubKey))
if err != nil {
return false, nil, err
}
// manually wrap the serialized signature in a string
s := Marshal(sign)
sig := make([]byte, stringLength(len(s)))
marshalString(sig, s)
msg := publickeyAuthMsg{
User: user,
Service: serviceSSH,
Method: cb.method(),
HasSig: true,
Algoname: pub.Type(),
PubKey: pubKey,
Sig: sig,
}
p := Marshal(&msg)
if err := c.writePacket(p); err != nil {
return false, nil, err
}
var success bool
success, methods, err = handleAuthResponse(c)
if err != nil {
return false, nil, err
}
if success {
return success, methods, err
}
}
return false, methods, nil
}
// validateKey validates the key provided is acceptable to the server.
func validateKey(key PublicKey, user string, c packetConn) (bool, error) {
pubKey := key.Marshal()
msg := publickeyAuthMsg{
User: user,
Service: serviceSSH,
Method: "publickey",
HasSig: false,
Algoname: key.Type(),
PubKey: pubKey,
}
if err := c.writePacket(Marshal(&msg)); err != nil {
return false, err
}
return confirmKeyAck(key, c)
}
func confirmKeyAck(key PublicKey, c packetConn) (bool, error) {
pubKey := key.Marshal()
algoname := key.Type()
for {
packet, err := c.readPacket()
if err != nil {
return false, err
}
switch packet[0] {
case msgUserAuthBanner:
// TODO(gpaul): add callback to present the banner to the user
case msgUserAuthPubKeyOk:
var msg userAuthPubKeyOkMsg
if err := Unmarshal(packet, &msg); err != nil {
return false, err
}
if msg.Algo != algoname || !bytes.Equal(msg.PubKey, pubKey) {
return false, nil
}
return true, nil
case msgUserAuthFailure:
return false, nil
default:
return false, unexpectedMessageError(msgUserAuthSuccess, packet[0])
}
}
}
// PublicKeys returns an AuthMethod that uses the given key
// pairs.
func PublicKeys(signers ...Signer) AuthMethod {
return publicKeyCallback(func() ([]Signer, error) { return signers, nil })
}
// PublicKeysCallback returns an AuthMethod that runs the given
// function to obtain a list of key pairs.
func PublicKeysCallback(getSigners func() (signers []Signer, err error)) AuthMethod {
return publicKeyCallback(getSigners)
}
// handleAuthResponse returns whether the preceding authentication request succeeded
// along with a list of remaining authentication methods to try next and
// an error if an unexpected response was received.
func handleAuthResponse(c packetConn) (bool, []string, error) {
for {
packet, err := c.readPacket()
if err != nil {
return false, nil, err
}
switch packet[0] {
case msgUserAuthBanner:
// TODO: add callback to present the banner to the user
case msgUserAuthFailure:
var msg userAuthFailureMsg
if err := Unmarshal(packet, &msg); err != nil {
return false, nil, err
}
return false, msg.Methods, nil
case msgUserAuthSuccess:
return true, nil, nil
case msgDisconnect:
return false, nil, io.EOF
default:
return false, nil, unexpectedMessageError(msgUserAuthSuccess, packet[0])
}
}
}
// KeyboardInteractiveChallenge should print questions, optionally
// disabling echoing (e.g. for passwords), and return all the answers.
// Challenge may be called multiple times in a single session. After
// successful authentication, the server may send a challenge with no
// questions, for which the user and instruction messages should be
// printed. RFC 4256 section 3.3 details how the UI should behave for
// both CLI and GUI environments.
type KeyboardInteractiveChallenge func(user, instruction string, questions []string, echos []bool) (answers []string, err error)
// KeyboardInteractive returns a AuthMethod using a prompt/response
// sequence controlled by the server.
func KeyboardInteractive(challenge KeyboardInteractiveChallenge) AuthMethod {
return challenge
}
func (cb KeyboardInteractiveChallenge) method() string {
return "keyboard-interactive"
}
func (cb KeyboardInteractiveChallenge) auth(session []byte, user string, c packetConn, rand io.Reader) (bool, []string, error) {
type initiateMsg struct {
User string `sshtype:"50"`
Service string
Method string
Language string
Submethods string
}
if err := c.writePacket(Marshal(&initiateMsg{
User: user,
Service: serviceSSH,
Method: "keyboard-interactive",
})); err != nil {
return false, nil, err
}
for {
packet, err := c.readPacket()
if err != nil {
return false, nil, err
}
// like handleAuthResponse, but with less options.
switch packet[0] {
case msgUserAuthBanner:
// TODO: Print banners during userauth.
continue
case msgUserAuthInfoRequest:
// OK
case msgUserAuthFailure:
var msg userAuthFailureMsg
if err := Unmarshal(packet, &msg); err != nil {
return false, nil, err
}
return false, msg.Methods, nil
case msgUserAuthSuccess:
return true, nil, nil
default:
return false, nil, unexpectedMessageError(msgUserAuthInfoRequest, packet[0])
}
var msg userAuthInfoRequestMsg
if err := Unmarshal(packet, &msg); err != nil {
return false, nil, err
}
// Manually unpack the prompt/echo pairs.
rest := msg.Prompts
var prompts []string
var echos []bool
for i := 0; i < int(msg.NumPrompts); i++ {
prompt, r, ok := parseString(rest)
if !ok || len(r) == 0 {
return false, nil, errors.New("ssh: prompt format error")
}
prompts = append(prompts, string(prompt))
echos = append(echos, r[0] != 0)
rest = r[1:]
}
if len(rest) != 0 {
return false, nil, errors.New("ssh: extra data following keyboard-interactive pairs")
}
answers, err := cb(msg.User, msg.Instruction, prompts, echos)
if err != nil {
return false, nil, err
}
if len(answers) != len(prompts) {
return false, nil, errors.New("ssh: not enough answers from keyboard-interactive callback")
}
responseLength := 1 + 4
for _, a := range answers {
responseLength += stringLength(len(a))
}
serialized := make([]byte, responseLength)
p := serialized
p[0] = msgUserAuthInfoResponse
p = p[1:]
p = marshalUint32(p, uint32(len(answers)))
for _, a := range answers {
p = marshalString(p, []byte(a))
}
if err := c.writePacket(serialized); err != nil {
return false, nil, err
}
}
}

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modules/crypto/ssh/client_auth_test.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"bytes"
"crypto/rand"
"errors"
"fmt"
"strings"
"testing"
)
type keyboardInteractive map[string]string
func (cr keyboardInteractive) Challenge(user string, instruction string, questions []string, echos []bool) ([]string, error) {
var answers []string
for _, q := range questions {
answers = append(answers, cr[q])
}
return answers, nil
}
// reused internally by tests
var clientPassword = "tiger"
// tryAuth runs a handshake with a given config against an SSH server
// with config serverConfig
func tryAuth(t *testing.T, config *ClientConfig) error {
c1, c2, err := netPipe()
if err != nil {
t.Fatalf("netPipe: %v", err)
}
defer c1.Close()
defer c2.Close()
certChecker := CertChecker{
IsAuthority: func(k PublicKey) bool {
return bytes.Equal(k.Marshal(), testPublicKeys["ecdsa"].Marshal())
},
UserKeyFallback: func(conn ConnMetadata, key PublicKey) (*Permissions, error) {
if conn.User() == "testuser" && bytes.Equal(key.Marshal(), testPublicKeys["rsa"].Marshal()) {
return nil, nil
}
return nil, fmt.Errorf("pubkey for %q not acceptable", conn.User())
},
IsRevoked: func(c *Certificate) bool {
return c.Serial == 666
},
}
serverConfig := &ServerConfig{
PasswordCallback: func(conn ConnMetadata, pass []byte) (*Permissions, error) {
if conn.User() == "testuser" && string(pass) == clientPassword {
return nil, nil
}
return nil, errors.New("password auth failed")
},
PublicKeyCallback: certChecker.Authenticate,
KeyboardInteractiveCallback: func(conn ConnMetadata, challenge KeyboardInteractiveChallenge) (*Permissions, error) {
ans, err := challenge("user",
"instruction",
[]string{"question1", "question2"},
[]bool{true, true})
if err != nil {
return nil, err
}
ok := conn.User() == "testuser" && ans[0] == "answer1" && ans[1] == "answer2"
if ok {
challenge("user", "motd", nil, nil)
return nil, nil
}
return nil, errors.New("keyboard-interactive failed")
},
AuthLogCallback: func(conn ConnMetadata, method string, err error) {
t.Logf("user %q, method %q: %v", conn.User(), method, err)
},
}
serverConfig.AddHostKey(testSigners["rsa"])
go newServer(c1, serverConfig)
_, _, _, err = NewClientConn(c2, "", config)
return err
}
func TestClientAuthPublicKey(t *testing.T) {
config := &ClientConfig{
User: "testuser",
Auth: []AuthMethod{
PublicKeys(testSigners["rsa"]),
},
}
if err := tryAuth(t, config); err != nil {
t.Fatalf("unable to dial remote side: %s", err)
}
}
func TestAuthMethodPassword(t *testing.T) {
config := &ClientConfig{
User: "testuser",
Auth: []AuthMethod{
Password(clientPassword),
},
}
if err := tryAuth(t, config); err != nil {
t.Fatalf("unable to dial remote side: %s", err)
}
}
func TestAuthMethodFallback(t *testing.T) {
var passwordCalled bool
config := &ClientConfig{
User: "testuser",
Auth: []AuthMethod{
PublicKeys(testSigners["rsa"]),
PasswordCallback(
func() (string, error) {
passwordCalled = true
return "WRONG", nil
}),
},
}
if err := tryAuth(t, config); err != nil {
t.Fatalf("unable to dial remote side: %s", err)
}
if passwordCalled {
t.Errorf("password auth tried before public-key auth.")
}
}
func TestAuthMethodWrongPassword(t *testing.T) {
config := &ClientConfig{
User: "testuser",
Auth: []AuthMethod{
Password("wrong"),
PublicKeys(testSigners["rsa"]),
},
}
if err := tryAuth(t, config); err != nil {
t.Fatalf("unable to dial remote side: %s", err)
}
}
func TestAuthMethodKeyboardInteractive(t *testing.T) {
answers := keyboardInteractive(map[string]string{
"question1": "answer1",
"question2": "answer2",
})
config := &ClientConfig{
User: "testuser",
Auth: []AuthMethod{
KeyboardInteractive(answers.Challenge),
},
}
if err := tryAuth(t, config); err != nil {
t.Fatalf("unable to dial remote side: %s", err)
}
}
func TestAuthMethodWrongKeyboardInteractive(t *testing.T) {
answers := keyboardInteractive(map[string]string{
"question1": "answer1",
"question2": "WRONG",
})
config := &ClientConfig{
User: "testuser",
Auth: []AuthMethod{
KeyboardInteractive(answers.Challenge),
},
}
if err := tryAuth(t, config); err == nil {
t.Fatalf("wrong answers should not have authenticated with KeyboardInteractive")
}
}
// the mock server will only authenticate ssh-rsa keys
func TestAuthMethodInvalidPublicKey(t *testing.T) {
config := &ClientConfig{
User: "testuser",
Auth: []AuthMethod{
PublicKeys(testSigners["dsa"]),
},
}
if err := tryAuth(t, config); err == nil {
t.Fatalf("dsa private key should not have authenticated with rsa public key")
}
}
// the client should authenticate with the second key
func TestAuthMethodRSAandDSA(t *testing.T) {
config := &ClientConfig{
User: "testuser",
Auth: []AuthMethod{
PublicKeys(testSigners["dsa"], testSigners["rsa"]),
},
}
if err := tryAuth(t, config); err != nil {
t.Fatalf("client could not authenticate with rsa key: %v", err)
}
}
func TestClientHMAC(t *testing.T) {
for _, mac := range supportedMACs {
config := &ClientConfig{
User: "testuser",
Auth: []AuthMethod{
PublicKeys(testSigners["rsa"]),
},
Config: Config{
MACs: []string{mac},
},
}
if err := tryAuth(t, config); err != nil {
t.Fatalf("client could not authenticate with mac algo %s: %v", mac, err)
}
}
}
// issue 4285.
func TestClientUnsupportedCipher(t *testing.T) {
config := &ClientConfig{
User: "testuser",
Auth: []AuthMethod{
PublicKeys(),
},
Config: Config{
Ciphers: []string{"aes128-cbc"}, // not currently supported
},
}
if err := tryAuth(t, config); err == nil {
t.Errorf("expected no ciphers in common")
}
}
func TestClientUnsupportedKex(t *testing.T) {
config := &ClientConfig{
User: "testuser",
Auth: []AuthMethod{
PublicKeys(),
},
Config: Config{
KeyExchanges: []string{"diffie-hellman-group-exchange-sha256"}, // not currently supported
},
}
if err := tryAuth(t, config); err == nil || !strings.Contains(err.Error(), "common algorithm") {
t.Errorf("got %v, expected 'common algorithm'", err)
}
}
func TestClientLoginCert(t *testing.T) {
cert := &Certificate{
Key: testPublicKeys["rsa"],
ValidBefore: CertTimeInfinity,
CertType: UserCert,
}
cert.SignCert(rand.Reader, testSigners["ecdsa"])
certSigner, err := NewCertSigner(cert, testSigners["rsa"])
if err != nil {
t.Fatalf("NewCertSigner: %v", err)
}
clientConfig := &ClientConfig{
User: "user",
}
clientConfig.Auth = append(clientConfig.Auth, PublicKeys(certSigner))
t.Log("should succeed")
if err := tryAuth(t, clientConfig); err != nil {
t.Errorf("cert login failed: %v", err)
}
t.Log("corrupted signature")
cert.Signature.Blob[0]++
if err := tryAuth(t, clientConfig); err == nil {
t.Errorf("cert login passed with corrupted sig")
}
t.Log("revoked")
cert.Serial = 666
cert.SignCert(rand.Reader, testSigners["ecdsa"])
if err := tryAuth(t, clientConfig); err == nil {
t.Errorf("revoked cert login succeeded")
}
cert.Serial = 1
t.Log("sign with wrong key")
cert.SignCert(rand.Reader, testSigners["dsa"])
if err := tryAuth(t, clientConfig); err == nil {
t.Errorf("cert login passed with non-authoritive key")
}
t.Log("host cert")
cert.CertType = HostCert
cert.SignCert(rand.Reader, testSigners["ecdsa"])
if err := tryAuth(t, clientConfig); err == nil {
t.Errorf("cert login passed with wrong type")
}
cert.CertType = UserCert
t.Log("principal specified")
cert.ValidPrincipals = []string{"user"}
cert.SignCert(rand.Reader, testSigners["ecdsa"])
if err := tryAuth(t, clientConfig); err != nil {
t.Errorf("cert login failed: %v", err)
}
t.Log("wrong principal specified")
cert.ValidPrincipals = []string{"fred"}
cert.SignCert(rand.Reader, testSigners["ecdsa"])
if err := tryAuth(t, clientConfig); err == nil {
t.Errorf("cert login passed with wrong principal")
}
cert.ValidPrincipals = nil
t.Log("added critical option")
cert.CriticalOptions = map[string]string{"root-access": "yes"}
cert.SignCert(rand.Reader, testSigners["ecdsa"])
if err := tryAuth(t, clientConfig); err == nil {
t.Errorf("cert login passed with unrecognized critical option")
}
t.Log("allowed source address")
cert.CriticalOptions = map[string]string{"source-address": "127.0.0.42/24"}
cert.SignCert(rand.Reader, testSigners["ecdsa"])
if err := tryAuth(t, clientConfig); err != nil {
t.Errorf("cert login with source-address failed: %v", err)
}
t.Log("disallowed source address")
cert.CriticalOptions = map[string]string{"source-address": "127.0.0.42"}
cert.SignCert(rand.Reader, testSigners["ecdsa"])
if err := tryAuth(t, clientConfig); err == nil {
t.Errorf("cert login with source-address succeeded")
}
}
func testPermissionsPassing(withPermissions bool, t *testing.T) {
serverConfig := &ServerConfig{
PublicKeyCallback: func(conn ConnMetadata, key PublicKey) (*Permissions, error) {
if conn.User() == "nopermissions" {
return nil, nil
} else {
return &Permissions{}, nil
}
},
}
serverConfig.AddHostKey(testSigners["rsa"])
clientConfig := &ClientConfig{
Auth: []AuthMethod{
PublicKeys(testSigners["rsa"]),
},
}
if withPermissions {
clientConfig.User = "permissions"
} else {
clientConfig.User = "nopermissions"
}
c1, c2, err := netPipe()
if err != nil {
t.Fatalf("netPipe: %v", err)
}
defer c1.Close()
defer c2.Close()
go NewClientConn(c2, "", clientConfig)
serverConn, err := newServer(c1, serverConfig)
if err != nil {
t.Fatal(err)
}
if p := serverConn.Permissions; (p != nil) != withPermissions {
t.Fatalf("withPermissions is %t, but Permissions object is %#v", withPermissions, p)
}
}
func TestPermissionsPassing(t *testing.T) {
testPermissionsPassing(true, t)
}
func TestNoPermissionsPassing(t *testing.T) {
testPermissionsPassing(false, t)
}

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modules/crypto/ssh/client_test.go
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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"net"
"testing"
)
func testClientVersion(t *testing.T, config *ClientConfig, expected string) {
clientConn, serverConn := net.Pipe()
defer clientConn.Close()
receivedVersion := make(chan string, 1)
go func() {
version, err := readVersion(serverConn)
if err != nil {
receivedVersion <- ""
} else {
receivedVersion <- string(version)
}
serverConn.Close()
}()
NewClientConn(clientConn, "", config)
actual := <-receivedVersion
if actual != expected {
t.Fatalf("got %s; want %s", actual, expected)
}
}
func TestCustomClientVersion(t *testing.T) {
version := "Test-Client-Version-0.0"
testClientVersion(t, &ClientConfig{ClientVersion: version}, version)
}
func TestDefaultClientVersion(t *testing.T) {
testClientVersion(t, &ClientConfig{}, packageVersion)
}

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modules/crypto/ssh/common.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"crypto"
"crypto/rand"
"fmt"
"io"
"sync"
_ "crypto/sha1"
_ "crypto/sha256"
_ "crypto/sha512"
)
// These are string constants in the SSH protocol.
const (
compressionNone = "none"
serviceUserAuth = "ssh-userauth"
serviceSSH = "ssh-connection"
)
// supportedCiphers specifies the supported ciphers in preference order.
var supportedCiphers = []string{
"aes128-ctr", "aes192-ctr", "aes256-ctr",
"aes128-gcm@openssh.com",
"arcfour256", "arcfour128",
}
// supportedKexAlgos specifies the supported key-exchange algorithms in
// preference order.
var supportedKexAlgos = []string{
kexAlgoCurve25519SHA256,
// P384 and P521 are not constant-time yet, but since we don't
// reuse ephemeral keys, using them for ECDH should be OK.
kexAlgoECDH256, kexAlgoECDH384, kexAlgoECDH521,
kexAlgoDH14SHA1, kexAlgoDH1SHA1,
}
// supportedKexAlgos specifies the supported host-key algorithms (i.e. methods
// of authenticating servers) in preference order.
var supportedHostKeyAlgos = []string{
CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01,
CertAlgoECDSA384v01, CertAlgoECDSA521v01,
KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521,
KeyAlgoRSA, KeyAlgoDSA,
}
// supportedMACs specifies a default set of MAC algorithms in preference order.
// This is based on RFC 4253, section 6.4, but with hmac-md5 variants removed
// because they have reached the end of their useful life.
var supportedMACs = []string{
"hmac-sha2-256", "hmac-sha1", "hmac-sha1-96",
}
var supportedCompressions = []string{compressionNone}
// hashFuncs keeps the mapping of supported algorithms to their respective
// hashes needed for signature verification.
var hashFuncs = map[string]crypto.Hash{
KeyAlgoRSA: crypto.SHA1,
KeyAlgoDSA: crypto.SHA1,
KeyAlgoECDSA256: crypto.SHA256,
KeyAlgoECDSA384: crypto.SHA384,
KeyAlgoECDSA521: crypto.SHA512,
CertAlgoRSAv01: crypto.SHA1,
CertAlgoDSAv01: crypto.SHA1,
CertAlgoECDSA256v01: crypto.SHA256,
CertAlgoECDSA384v01: crypto.SHA384,
CertAlgoECDSA521v01: crypto.SHA512,
}
// unexpectedMessageError results when the SSH message that we received didn't
// match what we wanted.
func unexpectedMessageError(expected, got uint8) error {
return fmt.Errorf("ssh: unexpected message type %d (expected %d)", got, expected)
}
// parseError results from a malformed SSH message.
func parseError(tag uint8) error {
return fmt.Errorf("ssh: parse error in message type %d", tag)
}
func findCommon(what string, client []string, server []string) (common string, err error) {
for _, c := range client {
for _, s := range server {
if c == s {
return c, nil
}
}
}
return "", fmt.Errorf("ssh: no common algorithm for %s; client offered: %v, server offered: %v", what, client, server)
}
type directionAlgorithms struct {
Cipher string
MAC string
Compression string
}
type algorithms struct {
kex string
hostKey string
w directionAlgorithms
r directionAlgorithms
}
func findAgreedAlgorithms(clientKexInit, serverKexInit *kexInitMsg) (algs *algorithms, err error) {
result := &algorithms{}
result.kex, err = findCommon("key exchange", clientKexInit.KexAlgos, serverKexInit.KexAlgos)
if err != nil {
return
}
result.hostKey, err = findCommon("host key", clientKexInit.ServerHostKeyAlgos, serverKexInit.ServerHostKeyAlgos)
if err != nil {
return
}
result.w.Cipher, err = findCommon("client to server cipher", clientKexInit.CiphersClientServer, serverKexInit.CiphersClientServer)
if err != nil {
return
}
result.r.Cipher, err = findCommon("server to client cipher", clientKexInit.CiphersServerClient, serverKexInit.CiphersServerClient)
if err != nil {
return
}
result.w.MAC, err = findCommon("client to server MAC", clientKexInit.MACsClientServer, serverKexInit.MACsClientServer)
if err != nil {
return
}
result.r.MAC, err = findCommon("server to client MAC", clientKexInit.MACsServerClient, serverKexInit.MACsServerClient)
if err != nil {
return
}
result.w.Compression, err = findCommon("client to server compression", clientKexInit.CompressionClientServer, serverKexInit.CompressionClientServer)
if err != nil {
return
}
result.r.Compression, err = findCommon("server to client compression", clientKexInit.CompressionServerClient, serverKexInit.CompressionServerClient)
if err != nil {
return
}
return result, nil
}
// If rekeythreshold is too small, we can't make any progress sending
// stuff.
const minRekeyThreshold uint64 = 256
// Config contains configuration data common to both ServerConfig and
// ClientConfig.
type Config struct {
// Rand provides the source of entropy for cryptographic
// primitives. If Rand is nil, the cryptographic random reader
// in package crypto/rand will be used.
Rand io.Reader
// The maximum number of bytes sent or received after which a
// new key is negotiated. It must be at least 256. If
// unspecified, 1 gigabyte is used.
RekeyThreshold uint64
// The allowed key exchanges algorithms. If unspecified then a
// default set of algorithms is used.
KeyExchanges []string
// The allowed cipher algorithms. If unspecified then a sensible
// default is used.
Ciphers []string
// The allowed MAC algorithms. If unspecified then a sensible default
// is used.
MACs []string
}
// SetDefaults sets sensible values for unset fields in config. This is
// exported for testing: Configs passed to SSH functions are copied and have
// default values set automatically.
func (c *Config) SetDefaults() {
if c.Rand == nil {
c.Rand = rand.Reader
}
if c.Ciphers == nil {
c.Ciphers = supportedCiphers
}
var ciphers []string
for _, c := range c.Ciphers {
if cipherModes[c] != nil {
// reject the cipher if we have no cipherModes definition
ciphers = append(ciphers, c)
}
}
c.Ciphers = ciphers
if c.KeyExchanges == nil {
c.KeyExchanges = supportedKexAlgos
}
if c.MACs == nil {
c.MACs = supportedMACs
}
if c.RekeyThreshold == 0 {
// RFC 4253, section 9 suggests rekeying after 1G.
c.RekeyThreshold = 1 << 30
}
if c.RekeyThreshold < minRekeyThreshold {
c.RekeyThreshold = minRekeyThreshold
}
}
// buildDataSignedForAuth returns the data that is signed in order to prove
// possession of a private key. See RFC 4252, section 7.
func buildDataSignedForAuth(sessionId []byte, req userAuthRequestMsg, algo, pubKey []byte) []byte {
data := struct {
Session []byte
Type byte
User string
Service string
Method string
Sign bool
Algo []byte
PubKey []byte
}{
sessionId,
msgUserAuthRequest,
req.User,
req.Service,
req.Method,
true,
algo,
pubKey,
}
return Marshal(data)
}
func appendU16(buf []byte, n uint16) []byte {
return append(buf, byte(n>>8), byte(n))
}
func appendU32(buf []byte, n uint32) []byte {
return append(buf, byte(n>>24), byte(n>>16), byte(n>>8), byte(n))
}
func appendU64(buf []byte, n uint64) []byte {
return append(buf,
byte(n>>56), byte(n>>48), byte(n>>40), byte(n>>32),
byte(n>>24), byte(n>>16), byte(n>>8), byte(n))
}
func appendInt(buf []byte, n int) []byte {
return appendU32(buf, uint32(n))
}
func appendString(buf []byte, s string) []byte {
buf = appendU32(buf, uint32(len(s)))
buf = append(buf, s...)
return buf
}
func appendBool(buf []byte, b bool) []byte {
if b {
return append(buf, 1)
}
return append(buf, 0)
}
// newCond is a helper to hide the fact that there is no usable zero
// value for sync.Cond.
func newCond() *sync.Cond { return sync.NewCond(new(sync.Mutex)) }
// window represents the buffer available to clients
// wishing to write to a channel.
type window struct {
*sync.Cond
win uint32 // RFC 4254 5.2 says the window size can grow to 2^32-1
writeWaiters int
closed bool
}
// add adds win to the amount of window available
// for consumers.
func (w *window) add(win uint32) bool {
// a zero sized window adjust is a noop.
if win == 0 {
return true
}
w.L.Lock()
if w.win+win < win {
w.L.Unlock()
return false
}
w.win += win
// It is unusual that multiple goroutines would be attempting to reserve
// window space, but not guaranteed. Use broadcast to notify all waiters
// that additional window is available.
w.Broadcast()
w.L.Unlock()
return true
}
// close sets the window to closed, so all reservations fail
// immediately.
func (w *window) close() {
w.L.Lock()
w.closed = true
w.Broadcast()
w.L.Unlock()
}
// reserve reserves win from the available window capacity.
// If no capacity remains, reserve will block. reserve may
// return less than requested.
func (w *window) reserve(win uint32) (uint32, error) {
var err error
w.L.Lock()
w.writeWaiters++
w.Broadcast()
for w.win == 0 && !w.closed {
w.Wait()
}
w.writeWaiters--
if w.win < win {
win = w.win
}
w.win -= win
if w.closed {
err = io.EOF
}
w.L.Unlock()
return win, err
}
// waitWriterBlocked waits until some goroutine is blocked for further
// writes. It is used in tests only.
func (w *window) waitWriterBlocked() {
w.Cond.L.Lock()
for w.writeWaiters == 0 {
w.Cond.Wait()
}
w.Cond.L.Unlock()
}

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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"fmt"
"net"
)
// OpenChannelError is returned if the other side rejects an
// OpenChannel request.
type OpenChannelError struct {
Reason RejectionReason
Message string
}
func (e *OpenChannelError) Error() string {
return fmt.Sprintf("ssh: rejected: %s (%s)", e.Reason, e.Message)
}
// ConnMetadata holds metadata for the connection.
type ConnMetadata interface {
// User returns the user ID for this connection.
// It is empty if no authentication is used.
User() string
// SessionID returns the sesson hash, also denoted by H.
SessionID() []byte
// ClientVersion returns the client's version string as hashed
// into the session ID.
ClientVersion() []byte
// ServerVersion returns the server's version string as hashed
// into the session ID.
ServerVersion() []byte
// RemoteAddr returns the remote address for this connection.
RemoteAddr() net.Addr
// LocalAddr returns the local address for this connection.
LocalAddr() net.Addr
}
// Conn represents an SSH connection for both server and client roles.
// Conn is the basis for implementing an application layer, such
// as ClientConn, which implements the traditional shell access for
// clients.
type Conn interface {
ConnMetadata
// SendRequest sends a global request, and returns the
// reply. If wantReply is true, it returns the response status
// and payload. See also RFC4254, section 4.
SendRequest(name string, wantReply bool, payload []byte) (bool, []byte, error)
// OpenChannel tries to open an channel. If the request is
// rejected, it returns *OpenChannelError. On success it returns
// the SSH Channel and a Go channel for incoming, out-of-band
// requests. The Go channel must be serviced, or the
// connection will hang.
OpenChannel(name string, data []byte) (Channel, <-chan *Request, error)
// Close closes the underlying network connection
Close() error
// Wait blocks until the connection has shut down, and returns the
// error causing the shutdown.
Wait() error
// TODO(hanwen): consider exposing:
// RequestKeyChange
// Disconnect
}
// DiscardRequests consumes and rejects all requests from the
// passed-in channel.
func DiscardRequests(in <-chan *Request) {
for req := range in {
if req.WantReply {
req.Reply(false, nil)
}
}
}
// A connection represents an incoming connection.
type connection struct {
transport *handshakeTransport
sshConn
// The connection protocol.
*mux
}
func (c *connection) Close() error {
return c.sshConn.conn.Close()
}
// sshconn provides net.Conn metadata, but disallows direct reads and
// writes.
type sshConn struct {
conn net.Conn
user string
sessionID []byte
clientVersion []byte
serverVersion []byte
}
func dup(src []byte) []byte {
dst := make([]byte, len(src))
copy(dst, src)
return dst
}
func (c *sshConn) User() string {
return c.user
}
func (c *sshConn) RemoteAddr() net.Addr {
return c.conn.RemoteAddr()
}
func (c *sshConn) Close() error {
return c.conn.Close()
}
func (c *sshConn) LocalAddr() net.Addr {
return c.conn.LocalAddr()
}
func (c *sshConn) SessionID() []byte {
return dup(c.sessionID)
}
func (c *sshConn) ClientVersion() []byte {
return dup(c.clientVersion)
}
func (c *sshConn) ServerVersion() []byte {
return dup(c.serverVersion)
}

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modules/crypto/ssh/doc.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
/*
Package ssh implements an SSH client and server.
SSH is a transport security protocol, an authentication protocol and a
family of application protocols. The most typical application level
protocol is a remote shell and this is specifically implemented. However,
the multiplexed nature of SSH is exposed to users that wish to support
others.
References:
[PROTOCOL.certkeys]: http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/PROTOCOL.certkeys?rev=HEAD
[SSH-PARAMETERS]: http://www.iana.org/assignments/ssh-parameters/ssh-parameters.xml#ssh-parameters-1
*/
package ssh // import "golang.org/x/crypto/ssh"

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modules/crypto/ssh/example_test.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh_test
import (
"bytes"
"fmt"
"io/ioutil"
"log"
"net"
"net/http"
"github.com/gogits/gogs/modules/crypto/ssh"
"github.com/gogits/gogs/modules/crypto/ssh/terminal"
)
func ExampleNewServerConn() {
// An SSH server is represented by a ServerConfig, which holds
// certificate details and handles authentication of ServerConns.
config := &ssh.ServerConfig{
PasswordCallback: func(c ssh.ConnMetadata, pass []byte) (*ssh.Permissions, error) {
// Should use constant-time compare (or better, salt+hash) in
// a production setting.
if c.User() == "testuser" && string(pass) == "tiger" {
return nil, nil
}
return nil, fmt.Errorf("password rejected for %q", c.User())
},
}
privateBytes, err := ioutil.ReadFile("id_rsa")
if err != nil {
panic("Failed to load private key")
}
private, err := ssh.ParsePrivateKey(privateBytes)
if err != nil {
panic("Failed to parse private key")
}
config.AddHostKey(private)
// Once a ServerConfig has been configured, connections can be
// accepted.
listener, err := net.Listen("tcp", "0.0.0.0:2022")
if err != nil {
panic("failed to listen for connection")
}
nConn, err := listener.Accept()
if err != nil {
panic("failed to accept incoming connection")
}
// Before use, a handshake must be performed on the incoming
// net.Conn.
_, chans, reqs, err := ssh.NewServerConn(nConn, config)
if err != nil {
panic("failed to handshake")
}
// The incoming Request channel must be serviced.
go ssh.DiscardRequests(reqs)
// Service the incoming Channel channel.
for newChannel := range chans {
// Channels have a type, depending on the application level
// protocol intended. In the case of a shell, the type is
// "session" and ServerShell may be used to present a simple
// terminal interface.
if newChannel.ChannelType() != "session" {
newChannel.Reject(ssh.UnknownChannelType, "unknown channel type")
continue
}
channel, requests, err := newChannel.Accept()
if err != nil {
panic("could not accept channel.")
}
// Sessions have out-of-band requests such as "shell",
// "pty-req" and "env". Here we handle only the
// "shell" request.
go func(in <-chan *ssh.Request) {
for req := range in {
ok := false
switch req.Type {
case "shell":
ok = true
if len(req.Payload) > 0 {
// We don't accept any
// commands, only the
// default shell.
ok = false
}
}
req.Reply(ok, nil)
}
}(requests)
term := terminal.NewTerminal(channel, "> ")
go func() {
defer channel.Close()
for {
line, err := term.ReadLine()
if err != nil {
break
}
fmt.Println(line)
}
}()
}
}
func ExampleDial() {
// An SSH client is represented with a ClientConn. Currently only
// the "password" authentication method is supported.
//
// To authenticate with the remote server you must pass at least one
// implementation of AuthMethod via the Auth field in ClientConfig.
config := &ssh.ClientConfig{
User: "username",
Auth: []ssh.AuthMethod{
ssh.Password("yourpassword"),
},
}
client, err := ssh.Dial("tcp", "yourserver.com:22", config)
if err != nil {
panic("Failed to dial: " + err.Error())
}
// Each ClientConn can support multiple interactive sessions,
// represented by a Session.
session, err := client.NewSession()
if err != nil {
panic("Failed to create session: " + err.Error())
}
defer session.Close()
// Once a Session is created, you can execute a single command on
// the remote side using the Run method.
var b bytes.Buffer
session.Stdout = &b
if err := session.Run("/usr/bin/whoami"); err != nil {
panic("Failed to run: " + err.Error())
}
fmt.Println(b.String())
}
func ExampleClient_Listen() {
config := &ssh.ClientConfig{
User: "username",
Auth: []ssh.AuthMethod{
ssh.Password("password"),
},
}
// Dial your ssh server.
conn, err := ssh.Dial("tcp", "localhost:22", config)
if err != nil {
log.Fatalf("unable to connect: %s", err)
}
defer conn.Close()
// Request the remote side to open port 8080 on all interfaces.
l, err := conn.Listen("tcp", "0.0.0.0:8080")
if err != nil {
log.Fatalf("unable to register tcp forward: %v", err)
}
defer l.Close()
// Serve HTTP with your SSH server acting as a reverse proxy.
http.Serve(l, http.HandlerFunc(func(resp http.ResponseWriter, req *http.Request) {
fmt.Fprintf(resp, "Hello world!\n")
}))
}
func ExampleSession_RequestPty() {
// Create client config
config := &ssh.ClientConfig{
User: "username",
Auth: []ssh.AuthMethod{
ssh.Password("password"),
},
}
// Connect to ssh server
conn, err := ssh.Dial("tcp", "localhost:22", config)
if err != nil {
log.Fatalf("unable to connect: %s", err)
}
defer conn.Close()
// Create a session
session, err := conn.NewSession()
if err != nil {
log.Fatalf("unable to create session: %s", err)
}
defer session.Close()
// Set up terminal modes
modes := ssh.TerminalModes{
ssh.ECHO: 0, // disable echoing
ssh.TTY_OP_ISPEED: 14400, // input speed = 14.4kbaud
ssh.TTY_OP_OSPEED: 14400, // output speed = 14.4kbaud
}
// Request pseudo terminal
if err := session.RequestPty("xterm", 80, 40, modes); err != nil {
log.Fatalf("request for pseudo terminal failed: %s", err)
}
// Start remote shell
if err := session.Shell(); err != nil {
log.Fatalf("failed to start shell: %s", err)
}
}

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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"crypto/rand"
"errors"
"fmt"
"io"
"log"
"net"
"sync"
)
// debugHandshake, if set, prints messages sent and received. Key
// exchange messages are printed as if DH were used, so the debug
// messages are wrong when using ECDH.
const debugHandshake = false
// keyingTransport is a packet based transport that supports key
// changes. It need not be thread-safe. It should pass through
// msgNewKeys in both directions.
type keyingTransport interface {
packetConn
// prepareKeyChange sets up a key change. The key change for a
// direction will be effected if a msgNewKeys message is sent
// or received.
prepareKeyChange(*algorithms, *kexResult) error
// getSessionID returns the session ID. prepareKeyChange must
// have been called once.
getSessionID() []byte
}
// rekeyingTransport is the interface of handshakeTransport that we
// (internally) expose to ClientConn and ServerConn.
type rekeyingTransport interface {
packetConn
// requestKeyChange asks the remote side to change keys. All
// writes are blocked until the key change succeeds, which is
// signaled by reading a msgNewKeys.
requestKeyChange() error
// getSessionID returns the session ID. This is only valid
// after the first key change has completed.
getSessionID() []byte
}
// handshakeTransport implements rekeying on top of a keyingTransport
// and offers a thread-safe writePacket() interface.
type handshakeTransport struct {
conn keyingTransport
config *Config
serverVersion []byte
clientVersion []byte
// hostKeys is non-empty if we are the server. In that case,
// it contains all host keys that can be used to sign the
// connection.
hostKeys []Signer
// hostKeyAlgorithms is non-empty if we are the client. In that case,
// we accept these key types from the server as host key.
hostKeyAlgorithms []string
// On read error, incoming is closed, and readError is set.
incoming chan []byte
readError error
// data for host key checking
hostKeyCallback func(hostname string, remote net.Addr, key PublicKey) error
dialAddress string
remoteAddr net.Addr
readSinceKex uint64
// Protects the writing side of the connection
mu sync.Mutex
cond *sync.Cond
sentInitPacket []byte
sentInitMsg *kexInitMsg
writtenSinceKex uint64
writeError error
}
func newHandshakeTransport(conn keyingTransport, config *Config, clientVersion, serverVersion []byte) *handshakeTransport {
t := &handshakeTransport{
conn: conn,
serverVersion: serverVersion,
clientVersion: clientVersion,
incoming: make(chan []byte, 16),
config: config,
}
t.cond = sync.NewCond(&t.mu)
return t
}
func newClientTransport(conn keyingTransport, clientVersion, serverVersion []byte, config *ClientConfig, dialAddr string, addr net.Addr) *handshakeTransport {
t := newHandshakeTransport(conn, &config.Config, clientVersion, serverVersion)
t.dialAddress = dialAddr
t.remoteAddr = addr
t.hostKeyCallback = config.HostKeyCallback
if config.HostKeyAlgorithms != nil {
t.hostKeyAlgorithms = config.HostKeyAlgorithms
} else {
t.hostKeyAlgorithms = supportedHostKeyAlgos
}
go t.readLoop()
return t
}
func newServerTransport(conn keyingTransport, clientVersion, serverVersion []byte, config *ServerConfig) *handshakeTransport {
t := newHandshakeTransport(conn, &config.Config, clientVersion, serverVersion)
t.hostKeys = config.hostKeys
go t.readLoop()
return t
}
func (t *handshakeTransport) getSessionID() []byte {
return t.conn.getSessionID()
}
func (t *handshakeTransport) id() string {
if len(t.hostKeys) > 0 {
return "server"
}
return "client"
}
func (t *handshakeTransport) readPacket() ([]byte, error) {
p, ok := <-t.incoming
if !ok {
return nil, t.readError
}
return p, nil
}
func (t *handshakeTransport) readLoop() {
for {
p, err := t.readOnePacket()
if err != nil {
t.readError = err
close(t.incoming)
break
}
if p[0] == msgIgnore || p[0] == msgDebug {
continue
}
t.incoming <- p
}
// If we can't read, declare the writing part dead too.
t.mu.Lock()
defer t.mu.Unlock()
if t.writeError == nil {
t.writeError = t.readError
}
t.cond.Broadcast()
}
func (t *handshakeTransport) readOnePacket() ([]byte, error) {
if t.readSinceKex > t.config.RekeyThreshold {
if err := t.requestKeyChange(); err != nil {
return nil, err
}
}
p, err := t.conn.readPacket()
if err != nil {
return nil, err
}
t.readSinceKex += uint64(len(p))
if debugHandshake {
msg, err := decode(p)
log.Printf("%s got %T %v (%v)", t.id(), msg, msg, err)
}
if p[0] != msgKexInit {
return p, nil
}
err = t.enterKeyExchange(p)
t.mu.Lock()
if err != nil {
// drop connection
t.conn.Close()
t.writeError = err
}
if debugHandshake {
log.Printf("%s exited key exchange, err %v", t.id(), err)
}
// Unblock writers.
t.sentInitMsg = nil
t.sentInitPacket = nil
t.cond.Broadcast()
t.writtenSinceKex = 0
t.mu.Unlock()
if err != nil {
return nil, err
}
t.readSinceKex = 0
return []byte{msgNewKeys}, nil
}
// sendKexInit sends a key change message, and returns the message
// that was sent. After initiating the key change, all writes will be
// blocked until the change is done, and a failed key change will
// close the underlying transport. This function is safe for
// concurrent use by multiple goroutines.
func (t *handshakeTransport) sendKexInit() (*kexInitMsg, []byte, error) {
t.mu.Lock()
defer t.mu.Unlock()
return t.sendKexInitLocked()
}
func (t *handshakeTransport) requestKeyChange() error {
_, _, err := t.sendKexInit()
return err
}
// sendKexInitLocked sends a key change message. t.mu must be locked
// while this happens.
func (t *handshakeTransport) sendKexInitLocked() (*kexInitMsg, []byte, error) {
// kexInits may be sent either in response to the other side,
// or because our side wants to initiate a key change, so we
// may have already sent a kexInit. In that case, don't send a
// second kexInit.
if t.sentInitMsg != nil {
return t.sentInitMsg, t.sentInitPacket, nil
}
msg := &kexInitMsg{
KexAlgos: t.config.KeyExchanges,
CiphersClientServer: t.config.Ciphers,
CiphersServerClient: t.config.Ciphers,
MACsClientServer: t.config.MACs,
MACsServerClient: t.config.MACs,
CompressionClientServer: supportedCompressions,
CompressionServerClient: supportedCompressions,
}
io.ReadFull(rand.Reader, msg.Cookie[:])
if len(t.hostKeys) > 0 {
for _, k := range t.hostKeys {
msg.ServerHostKeyAlgos = append(
msg.ServerHostKeyAlgos, k.PublicKey().Type())
}
} else {
msg.ServerHostKeyAlgos = t.hostKeyAlgorithms
}
packet := Marshal(msg)
// writePacket destroys the contents, so save a copy.
packetCopy := make([]byte, len(packet))
copy(packetCopy, packet)
if err := t.conn.writePacket(packetCopy); err != nil {
return nil, nil, err
}
t.sentInitMsg = msg
t.sentInitPacket = packet
return msg, packet, nil
}
func (t *handshakeTransport) writePacket(p []byte) error {
t.mu.Lock()
defer t.mu.Unlock()
if t.writtenSinceKex > t.config.RekeyThreshold {
t.sendKexInitLocked()
}
for t.sentInitMsg != nil && t.writeError == nil {
t.cond.Wait()
}
if t.writeError != nil {
return t.writeError
}
t.writtenSinceKex += uint64(len(p))
switch p[0] {
case msgKexInit:
return errors.New("ssh: only handshakeTransport can send kexInit")
case msgNewKeys:
return errors.New("ssh: only handshakeTransport can send newKeys")
default:
return t.conn.writePacket(p)
}
}
func (t *handshakeTransport) Close() error {
return t.conn.Close()
}
// enterKeyExchange runs the key exchange.
func (t *handshakeTransport) enterKeyExchange(otherInitPacket []byte) error {
if debugHandshake {
log.Printf("%s entered key exchange", t.id())
}
myInit, myInitPacket, err := t.sendKexInit()
if err != nil {
return err
}
otherInit := &kexInitMsg{}
if err := Unmarshal(otherInitPacket, otherInit); err != nil {
return err
}
magics := handshakeMagics{
clientVersion: t.clientVersion,
serverVersion: t.serverVersion,
clientKexInit: otherInitPacket,
serverKexInit: myInitPacket,
}
clientInit := otherInit
serverInit := myInit
if len(t.hostKeys) == 0 {
clientInit = myInit
serverInit = otherInit
magics.clientKexInit = myInitPacket
magics.serverKexInit = otherInitPacket
}
algs, err := findAgreedAlgorithms(clientInit, serverInit)
if err != nil {
return err
}
// We don't send FirstKexFollows, but we handle receiving it.
if otherInit.FirstKexFollows && algs.kex != otherInit.KexAlgos[0] {
// other side sent a kex message for the wrong algorithm,
// which we have to ignore.
if _, err := t.conn.readPacket(); err != nil {
return err
}
}
kex, ok := kexAlgoMap[algs.kex]
if !ok {
return fmt.Errorf("ssh: unexpected key exchange algorithm %v", algs.kex)
}
var result *kexResult
if len(t.hostKeys) > 0 {
result, err = t.server(kex, algs, &magics)
} else {
result, err = t.client(kex, algs, &magics)
}
if err != nil {
return err
}
t.conn.prepareKeyChange(algs, result)
if err = t.conn.writePacket([]byte{msgNewKeys}); err != nil {
return err
}
if packet, err := t.conn.readPacket(); err != nil {
return err
} else if packet[0] != msgNewKeys {
return unexpectedMessageError(msgNewKeys, packet[0])
}
return nil
}
func (t *handshakeTransport) server(kex kexAlgorithm, algs *algorithms, magics *handshakeMagics) (*kexResult, error) {
var hostKey Signer
for _, k := range t.hostKeys {
if algs.hostKey == k.PublicKey().Type() {
hostKey = k
}
}
r, err := kex.Server(t.conn, t.config.Rand, magics, hostKey)
return r, err
}
func (t *handshakeTransport) client(kex kexAlgorithm, algs *algorithms, magics *handshakeMagics) (*kexResult, error) {
result, err := kex.Client(t.conn, t.config.Rand, magics)
if err != nil {
return nil, err
}
hostKey, err := ParsePublicKey(result.HostKey)
if err != nil {
return nil, err
}
if err := verifyHostKeySignature(hostKey, result); err != nil {
return nil, err
}
if t.hostKeyCallback != nil {
err = t.hostKeyCallback(t.dialAddress, t.remoteAddr, hostKey)
if err != nil {
return nil, err
}
}
return result, nil
}

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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"bytes"
"crypto/rand"
"errors"
"fmt"
"net"
"runtime"
"strings"
"sync"
"testing"
)
type testChecker struct {
calls []string
}
func (t *testChecker) Check(dialAddr string, addr net.Addr, key PublicKey) error {
if dialAddr == "bad" {
return fmt.Errorf("dialAddr is bad")
}
if tcpAddr, ok := addr.(*net.TCPAddr); !ok || tcpAddr == nil {
return fmt.Errorf("testChecker: got %T want *net.TCPAddr", addr)
}
t.calls = append(t.calls, fmt.Sprintf("%s %v %s %x", dialAddr, addr, key.Type(), key.Marshal()))
return nil
}
// netPipe is analogous to net.Pipe, but it uses a real net.Conn, and
// therefore is buffered (net.Pipe deadlocks if both sides start with
// a write.)
func netPipe() (net.Conn, net.Conn, error) {
listener, err := net.Listen("tcp", "127.0.0.1:0")
if err != nil {
return nil, nil, err
}
defer listener.Close()
c1, err := net.Dial("tcp", listener.Addr().String())
if err != nil {
return nil, nil, err
}
c2, err := listener.Accept()
if err != nil {
c1.Close()
return nil, nil, err
}
return c1, c2, nil
}
func handshakePair(clientConf *ClientConfig, addr string) (client *handshakeTransport, server *handshakeTransport, err error) {
a, b, err := netPipe()
if err != nil {
return nil, nil, err
}
trC := newTransport(a, rand.Reader, true)
trS := newTransport(b, rand.Reader, false)
clientConf.SetDefaults()
v := []byte("version")
client = newClientTransport(trC, v, v, clientConf, addr, a.RemoteAddr())
serverConf := &ServerConfig{}
serverConf.AddHostKey(testSigners["ecdsa"])
serverConf.AddHostKey(testSigners["rsa"])
serverConf.SetDefaults()
server = newServerTransport(trS, v, v, serverConf)
return client, server, nil
}
func TestHandshakeBasic(t *testing.T) {
if runtime.GOOS == "plan9" {
t.Skip("see golang.org/issue/7237")
}
checker := &testChecker{}
trC, trS, err := handshakePair(&ClientConfig{HostKeyCallback: checker.Check}, "addr")
if err != nil {
t.Fatalf("handshakePair: %v", err)
}
defer trC.Close()
defer trS.Close()
go func() {
// Client writes a bunch of stuff, and does a key
// change in the middle. This should not confuse the
// handshake in progress
for i := 0; i < 10; i++ {
p := []byte{msgRequestSuccess, byte(i)}
if err := trC.writePacket(p); err != nil {
t.Fatalf("sendPacket: %v", err)
}
if i == 5 {
// halfway through, we request a key change.
_, _, err := trC.sendKexInit()
if err != nil {
t.Fatalf("sendKexInit: %v", err)
}
}
}
trC.Close()
}()
// Server checks that client messages come in cleanly
i := 0
for {
p, err := trS.readPacket()
if err != nil {
break
}
if p[0] == msgNewKeys {
continue
}
want := []byte{msgRequestSuccess, byte(i)}
if bytes.Compare(p, want) != 0 {
t.Errorf("message %d: got %q, want %q", i, p, want)
}
i++
}
if i != 10 {
t.Errorf("received %d messages, want 10.", i)
}
// If all went well, we registered exactly 1 key change.
if len(checker.calls) != 1 {
t.Fatalf("got %d host key checks, want 1", len(checker.calls))
}
pub := testSigners["ecdsa"].PublicKey()
want := fmt.Sprintf("%s %v %s %x", "addr", trC.remoteAddr, pub.Type(), pub.Marshal())
if want != checker.calls[0] {
t.Errorf("got %q want %q for host key check", checker.calls[0], want)
}
}
func TestHandshakeError(t *testing.T) {
checker := &testChecker{}
trC, trS, err := handshakePair(&ClientConfig{HostKeyCallback: checker.Check}, "bad")
if err != nil {
t.Fatalf("handshakePair: %v", err)
}
defer trC.Close()
defer trS.Close()
// send a packet
packet := []byte{msgRequestSuccess, 42}
if err := trC.writePacket(packet); err != nil {
t.Errorf("writePacket: %v", err)
}
// Now request a key change.
_, _, err = trC.sendKexInit()
if err != nil {
t.Errorf("sendKexInit: %v", err)
}
// the key change will fail, and afterwards we can't write.
if err := trC.writePacket([]byte{msgRequestSuccess, 43}); err == nil {
t.Errorf("writePacket after botched rekey succeeded.")
}
readback, err := trS.readPacket()
if err != nil {
t.Fatalf("server closed too soon: %v", err)
}
if bytes.Compare(readback, packet) != 0 {
t.Errorf("got %q want %q", readback, packet)
}
readback, err = trS.readPacket()
if err == nil {
t.Errorf("got a message %q after failed key change", readback)
}
}
func TestHandshakeTwice(t *testing.T) {
checker := &testChecker{}
trC, trS, err := handshakePair(&ClientConfig{HostKeyCallback: checker.Check}, "addr")
if err != nil {
t.Fatalf("handshakePair: %v", err)
}
defer trC.Close()
defer trS.Close()
// send a packet
packet := make([]byte, 5)
packet[0] = msgRequestSuccess
if err := trC.writePacket(packet); err != nil {
t.Errorf("writePacket: %v", err)
}
// Now request a key change.
_, _, err = trC.sendKexInit()
if err != nil {
t.Errorf("sendKexInit: %v", err)
}
// Send another packet. Use a fresh one, since writePacket destroys.
packet = make([]byte, 5)
packet[0] = msgRequestSuccess
if err := trC.writePacket(packet); err != nil {
t.Errorf("writePacket: %v", err)
}
// 2nd key change.
_, _, err = trC.sendKexInit()
if err != nil {
t.Errorf("sendKexInit: %v", err)
}
packet = make([]byte, 5)
packet[0] = msgRequestSuccess
if err := trC.writePacket(packet); err != nil {
t.Errorf("writePacket: %v", err)
}
packet = make([]byte, 5)
packet[0] = msgRequestSuccess
for i := 0; i < 5; i++ {
msg, err := trS.readPacket()
if err != nil {
t.Fatalf("server closed too soon: %v", err)
}
if msg[0] == msgNewKeys {
continue
}
if bytes.Compare(msg, packet) != 0 {
t.Errorf("packet %d: got %q want %q", i, msg, packet)
}
}
if len(checker.calls) != 2 {
t.Errorf("got %d key changes, want 2", len(checker.calls))
}
}
func TestHandshakeAutoRekeyWrite(t *testing.T) {
checker := &testChecker{}
clientConf := &ClientConfig{HostKeyCallback: checker.Check}
clientConf.RekeyThreshold = 500
trC, trS, err := handshakePair(clientConf, "addr")
if err != nil {
t.Fatalf("handshakePair: %v", err)
}
defer trC.Close()
defer trS.Close()
for i := 0; i < 5; i++ {
packet := make([]byte, 251)
packet[0] = msgRequestSuccess
if err := trC.writePacket(packet); err != nil {
t.Errorf("writePacket: %v", err)
}
}
j := 0
for ; j < 5; j++ {
_, err := trS.readPacket()
if err != nil {
break
}
}
if j != 5 {
t.Errorf("got %d, want 5 messages", j)
}
if len(checker.calls) != 2 {
t.Errorf("got %d key changes, wanted 2", len(checker.calls))
}
}
type syncChecker struct {
called chan int
}
func (t *syncChecker) Check(dialAddr string, addr net.Addr, key PublicKey) error {
t.called <- 1
return nil
}
func TestHandshakeAutoRekeyRead(t *testing.T) {
sync := &syncChecker{make(chan int, 2)}
clientConf := &ClientConfig{
HostKeyCallback: sync.Check,
}
clientConf.RekeyThreshold = 500
trC, trS, err := handshakePair(clientConf, "addr")
if err != nil {
t.Fatalf("handshakePair: %v", err)
}
defer trC.Close()
defer trS.Close()
packet := make([]byte, 501)
packet[0] = msgRequestSuccess
if err := trS.writePacket(packet); err != nil {
t.Fatalf("writePacket: %v", err)
}
// While we read out the packet, a key change will be
// initiated.
if _, err := trC.readPacket(); err != nil {
t.Fatalf("readPacket(client): %v", err)
}
<-sync.called
}
// errorKeyingTransport generates errors after a given number of
// read/write operations.
type errorKeyingTransport struct {
packetConn
readLeft, writeLeft int
}
func (n *errorKeyingTransport) prepareKeyChange(*algorithms, *kexResult) error {
return nil
}
func (n *errorKeyingTransport) getSessionID() []byte {
return nil
}
func (n *errorKeyingTransport) writePacket(packet []byte) error {
if n.writeLeft == 0 {
n.Close()
return errors.New("barf")
}
n.writeLeft--
return n.packetConn.writePacket(packet)
}
func (n *errorKeyingTransport) readPacket() ([]byte, error) {
if n.readLeft == 0 {
n.Close()
return nil, errors.New("barf")
}
n.readLeft--
return n.packetConn.readPacket()
}
func TestHandshakeErrorHandlingRead(t *testing.T) {
for i := 0; i < 20; i++ {
testHandshakeErrorHandlingN(t, i, -1)
}
}
func TestHandshakeErrorHandlingWrite(t *testing.T) {
for i := 0; i < 20; i++ {
testHandshakeErrorHandlingN(t, -1, i)
}
}
// testHandshakeErrorHandlingN runs handshakes, injecting errors. If
// handshakeTransport deadlocks, the go runtime will detect it and
// panic.
func testHandshakeErrorHandlingN(t *testing.T, readLimit, writeLimit int) {
msg := Marshal(&serviceRequestMsg{strings.Repeat("x", int(minRekeyThreshold)/4)})
a, b := memPipe()
defer a.Close()
defer b.Close()
key := testSigners["ecdsa"]
serverConf := Config{RekeyThreshold: minRekeyThreshold}
serverConf.SetDefaults()
serverConn := newHandshakeTransport(&errorKeyingTransport{a, readLimit, writeLimit}, &serverConf, []byte{'a'}, []byte{'b'})
serverConn.hostKeys = []Signer{key}
go serverConn.readLoop()
clientConf := Config{RekeyThreshold: 10 * minRekeyThreshold}
clientConf.SetDefaults()
clientConn := newHandshakeTransport(&errorKeyingTransport{b, -1, -1}, &clientConf, []byte{'a'}, []byte{'b'})
clientConn.hostKeyAlgorithms = []string{key.PublicKey().Type()}
go clientConn.readLoop()
var wg sync.WaitGroup
wg.Add(4)
for _, hs := range []packetConn{serverConn, clientConn} {
go func(c packetConn) {
for {
err := c.writePacket(msg)
if err != nil {
break
}
}
wg.Done()
}(hs)
go func(c packetConn) {
for {
_, err := c.readPacket()
if err != nil {
break
}
}
wg.Done()
}(hs)
}
wg.Wait()
}

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modules/crypto/ssh/kex.go
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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"crypto"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/subtle"
"crypto/rand"
"errors"
"io"
"math/big"
"golang.org/x/crypto/curve25519"
)
const (
kexAlgoDH1SHA1 = "diffie-hellman-group1-sha1"
kexAlgoDH14SHA1 = "diffie-hellman-group14-sha1"
kexAlgoECDH256 = "ecdh-sha2-nistp256"
kexAlgoECDH384 = "ecdh-sha2-nistp384"
kexAlgoECDH521 = "ecdh-sha2-nistp521"
kexAlgoCurve25519SHA256 = "curve25519-sha256@libssh.org"
)
// kexResult captures the outcome of a key exchange.
type kexResult struct {
// Session hash. See also RFC 4253, section 8.
H []byte
// Shared secret. See also RFC 4253, section 8.
K []byte
// Host key as hashed into H.
HostKey []byte
// Signature of H.
Signature []byte
// A cryptographic hash function that matches the security
// level of the key exchange algorithm. It is used for
// calculating H, and for deriving keys from H and K.
Hash crypto.Hash
// The session ID, which is the first H computed. This is used
// to signal data inside transport.
SessionID []byte
}
// handshakeMagics contains data that is always included in the
// session hash.
type handshakeMagics struct {
clientVersion, serverVersion []byte
clientKexInit, serverKexInit []byte
}
func (m *handshakeMagics) write(w io.Writer) {
writeString(w, m.clientVersion)
writeString(w, m.serverVersion)
writeString(w, m.clientKexInit)
writeString(w, m.serverKexInit)
}
// kexAlgorithm abstracts different key exchange algorithms.
type kexAlgorithm interface {
// Server runs server-side key agreement, signing the result
// with a hostkey.
Server(p packetConn, rand io.Reader, magics *handshakeMagics, s Signer) (*kexResult, error)
// Client runs the client-side key agreement. Caller is
// responsible for verifying the host key signature.
Client(p packetConn, rand io.Reader, magics *handshakeMagics) (*kexResult, error)
}
// dhGroup is a multiplicative group suitable for implementing Diffie-Hellman key agreement.
type dhGroup struct {
g, p *big.Int
}
func (group *dhGroup) diffieHellman(theirPublic, myPrivate *big.Int) (*big.Int, error) {
if theirPublic.Sign() <= 0 || theirPublic.Cmp(group.p) >= 0 {
return nil, errors.New("ssh: DH parameter out of bounds")
}
return new(big.Int).Exp(theirPublic, myPrivate, group.p), nil
}
func (group *dhGroup) Client(c packetConn, randSource io.Reader, magics *handshakeMagics) (*kexResult, error) {
hashFunc := crypto.SHA1
x, err := rand.Int(randSource, group.p)
if err != nil {
return nil, err
}
X := new(big.Int).Exp(group.g, x, group.p)
kexDHInit := kexDHInitMsg{
X: X,
}
if err := c.writePacket(Marshal(&kexDHInit)); err != nil {
return nil, err
}
packet, err := c.readPacket()
if err != nil {
return nil, err
}
var kexDHReply kexDHReplyMsg
if err = Unmarshal(packet, &kexDHReply); err != nil {
return nil, err
}
kInt, err := group.diffieHellman(kexDHReply.Y, x)
if err != nil {
return nil, err
}
h := hashFunc.New()
magics.write(h)
writeString(h, kexDHReply.HostKey)
writeInt(h, X)
writeInt(h, kexDHReply.Y)
K := make([]byte, intLength(kInt))
marshalInt(K, kInt)
h.Write(K)
return &kexResult{
H: h.Sum(nil),
K: K,
HostKey: kexDHReply.HostKey,
Signature: kexDHReply.Signature,
Hash: crypto.SHA1,
}, nil
}
func (group *dhGroup) Server(c packetConn, randSource io.Reader, magics *handshakeMagics, priv Signer) (result *kexResult, err error) {
hashFunc := crypto.SHA1
packet, err := c.readPacket()
if err != nil {
return
}
var kexDHInit kexDHInitMsg
if err = Unmarshal(packet, &kexDHInit); err != nil {
return
}
y, err := rand.Int(randSource, group.p)
if err != nil {
return
}
Y := new(big.Int).Exp(group.g, y, group.p)
kInt, err := group.diffieHellman(kexDHInit.X, y)
if err != nil {
return nil, err
}
hostKeyBytes := priv.PublicKey().Marshal()
h := hashFunc.New()
magics.write(h)
writeString(h, hostKeyBytes)
writeInt(h, kexDHInit.X)
writeInt(h, Y)
K := make([]byte, intLength(kInt))
marshalInt(K, kInt)
h.Write(K)
H := h.Sum(nil)
// H is already a hash, but the hostkey signing will apply its
// own key-specific hash algorithm.
sig, err := signAndMarshal(priv, randSource, H)
if err != nil {
return nil, err
}
kexDHReply := kexDHReplyMsg{
HostKey: hostKeyBytes,
Y: Y,
Signature: sig,
}
packet = Marshal(&kexDHReply)
err = c.writePacket(packet)
return &kexResult{
H: H,
K: K,
HostKey: hostKeyBytes,
Signature: sig,
Hash: crypto.SHA1,
}, nil
}
// ecdh performs Elliptic Curve Diffie-Hellman key exchange as
// described in RFC 5656, section 4.
type ecdh struct {
curve elliptic.Curve
}
func (kex *ecdh) Client(c packetConn, rand io.Reader, magics *handshakeMagics) (*kexResult, error) {
ephKey, err := ecdsa.GenerateKey(kex.curve, rand)
if err != nil {
return nil, err
}
kexInit := kexECDHInitMsg{
ClientPubKey: elliptic.Marshal(kex.curve, ephKey.PublicKey.X, ephKey.PublicKey.Y),
}
serialized := Marshal(&kexInit)
if err := c.writePacket(serialized); err != nil {
return nil, err
}
packet, err := c.readPacket()
if err != nil {
return nil, err
}
var reply kexECDHReplyMsg
if err = Unmarshal(packet, &reply); err != nil {
return nil, err
}
x, y, err := unmarshalECKey(kex.curve, reply.EphemeralPubKey)
if err != nil {
return nil, err
}
// generate shared secret
secret, _ := kex.curve.ScalarMult(x, y, ephKey.D.Bytes())
h := ecHash(kex.curve).New()
magics.write(h)
writeString(h, reply.HostKey)
writeString(h, kexInit.ClientPubKey)
writeString(h, reply.EphemeralPubKey)
K := make([]byte, intLength(secret))
marshalInt(K, secret)
h.Write(K)
return &kexResult{
H: h.Sum(nil),
K: K,
HostKey: reply.HostKey,
Signature: reply.Signature,
Hash: ecHash(kex.curve),
}, nil
}
// unmarshalECKey parses and checks an EC key.
func unmarshalECKey(curve elliptic.Curve, pubkey []byte) (x, y *big.Int, err error) {
x, y = elliptic.Unmarshal(curve, pubkey)
if x == nil {
return nil, nil, errors.New("ssh: elliptic.Unmarshal failure")
}
if !validateECPublicKey(curve, x, y) {
return nil, nil, errors.New("ssh: public key not on curve")
}
return x, y, nil
}
// validateECPublicKey checks that the point is a valid public key for
// the given curve. See [SEC1], 3.2.2
func validateECPublicKey(curve elliptic.Curve, x, y *big.Int) bool {
if x.Sign() == 0 && y.Sign() == 0 {
return false
}
if x.Cmp(curve.Params().P) >= 0 {
return false
}
if y.Cmp(curve.Params().P) >= 0 {
return false
}
if !curve.IsOnCurve(x, y) {
return false
}
// We don't check if N * PubKey == 0, since
//
// - the NIST curves have cofactor = 1, so this is implicit.
// (We don't foresee an implementation that supports non NIST
// curves)
//
// - for ephemeral keys, we don't need to worry about small
// subgroup attacks.
return true
}
func (kex *ecdh) Server(c packetConn, rand io.Reader, magics *handshakeMagics, priv Signer) (result *kexResult, err error) {
packet, err := c.readPacket()
if err != nil {
return nil, err
}
var kexECDHInit kexECDHInitMsg
if err = Unmarshal(packet, &kexECDHInit); err != nil {
return nil, err
}
clientX, clientY, err := unmarshalECKey(kex.curve, kexECDHInit.ClientPubKey)
if err != nil {
return nil, err
}
// We could cache this key across multiple users/multiple
// connection attempts, but the benefit is small. OpenSSH
// generates a new key for each incoming connection.
ephKey, err := ecdsa.GenerateKey(kex.curve, rand)
if err != nil {
return nil, err
}
hostKeyBytes := priv.PublicKey().Marshal()
serializedEphKey := elliptic.Marshal(kex.curve, ephKey.PublicKey.X, ephKey.PublicKey.Y)
// generate shared secret
secret, _ := kex.curve.ScalarMult(clientX, clientY, ephKey.D.Bytes())
h := ecHash(kex.curve).New()
magics.write(h)
writeString(h, hostKeyBytes)
writeString(h, kexECDHInit.ClientPubKey)
writeString(h, serializedEphKey)
K := make([]byte, intLength(secret))
marshalInt(K, secret)
h.Write(K)
H := h.Sum(nil)
// H is already a hash, but the hostkey signing will apply its
// own key-specific hash algorithm.
sig, err := signAndMarshal(priv, rand, H)
if err != nil {
return nil, err
}
reply := kexECDHReplyMsg{
EphemeralPubKey: serializedEphKey,
HostKey: hostKeyBytes,
Signature: sig,
}
serialized := Marshal(&reply)
if err := c.writePacket(serialized); err != nil {
return nil, err
}
return &kexResult{
H: H,
K: K,
HostKey: reply.HostKey,
Signature: sig,
Hash: ecHash(kex.curve),
}, nil
}
var kexAlgoMap = map[string]kexAlgorithm{}
func init() {
// This is the group called diffie-hellman-group1-sha1 in RFC
// 4253 and Oakley Group 2 in RFC 2409.
p, _ := new(big.Int).SetString("FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE65381FFFFFFFFFFFFFFFF", 16)
kexAlgoMap[kexAlgoDH1SHA1] = &dhGroup{
g: new(big.Int).SetInt64(2),
p: p,
}
// This is the group called diffie-hellman-group14-sha1 in RFC
// 4253 and Oakley Group 14 in RFC 3526.
p, _ = new(big.Int).SetString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
kexAlgoMap[kexAlgoDH14SHA1] = &dhGroup{
g: new(big.Int).SetInt64(2),
p: p,
}
kexAlgoMap[kexAlgoECDH521] = &ecdh{elliptic.P521()}
kexAlgoMap[kexAlgoECDH384] = &ecdh{elliptic.P384()}
kexAlgoMap[kexAlgoECDH256] = &ecdh{elliptic.P256()}
kexAlgoMap[kexAlgoCurve25519SHA256] = &curve25519sha256{}
}
// curve25519sha256 implements the curve25519-sha256@libssh.org key
// agreement protocol, as described in
// https://git.libssh.org/projects/libssh.git/tree/doc/curve25519-sha256@libssh.org.txt
type curve25519sha256 struct{}
type curve25519KeyPair struct {
priv [32]byte
pub [32]byte
}
func (kp *curve25519KeyPair) generate(rand io.Reader) error {
if _, err := io.ReadFull(rand, kp.priv[:]); err != nil {
return err
}
curve25519.ScalarBaseMult(&kp.pub, &kp.priv)
return nil
}
// curve25519Zeros is just an array of 32 zero bytes so that we have something
// convenient to compare against in order to reject curve25519 points with the
// wrong order.
var curve25519Zeros [32]byte
func (kex *curve25519sha256) Client(c packetConn, rand io.Reader, magics *handshakeMagics) (*kexResult, error) {
var kp curve25519KeyPair
if err := kp.generate(rand); err != nil {
return nil, err
}
if err := c.writePacket(Marshal(&kexECDHInitMsg{kp.pub[:]})); err != nil {
return nil, err
}
packet, err := c.readPacket()
if err != nil {
return nil, err
}
var reply kexECDHReplyMsg
if err = Unmarshal(packet, &reply); err != nil {
return nil, err
}
if len(reply.EphemeralPubKey) != 32 {
return nil, errors.New("ssh: peer's curve25519 public value has wrong length")
}
var servPub, secret [32]byte
copy(servPub[:], reply.EphemeralPubKey)
curve25519.ScalarMult(&secret, &kp.priv, &servPub)
if subtle.ConstantTimeCompare(secret[:], curve25519Zeros[:]) == 1 {
return nil, errors.New("ssh: peer's curve25519 public value has wrong order")
}
h := crypto.SHA256.New()
magics.write(h)
writeString(h, reply.HostKey)
writeString(h, kp.pub[:])
writeString(h, reply.EphemeralPubKey)
kInt := new(big.Int).SetBytes(secret[:])
K := make([]byte, intLength(kInt))
marshalInt(K, kInt)
h.Write(K)
return &kexResult{
H: h.Sum(nil),
K: K,
HostKey: reply.HostKey,
Signature: reply.Signature,
Hash: crypto.SHA256,
}, nil
}
func (kex *curve25519sha256) Server(c packetConn, rand io.Reader, magics *handshakeMagics, priv Signer) (result *kexResult, err error) {
packet, err := c.readPacket()
if err != nil {
return
}
var kexInit kexECDHInitMsg
if err = Unmarshal(packet, &kexInit); err != nil {
return
}
if len(kexInit.ClientPubKey) != 32 {
return nil, errors.New("ssh: peer's curve25519 public value has wrong length")
}
var kp curve25519KeyPair
if err := kp.generate(rand); err != nil {
return nil, err
}
var clientPub, secret [32]byte
copy(clientPub[:], kexInit.ClientPubKey)
curve25519.ScalarMult(&secret, &kp.priv, &clientPub)
if subtle.ConstantTimeCompare(secret[:], curve25519Zeros[:]) == 1 {
return nil, errors.New("ssh: peer's curve25519 public value has wrong order")
}
hostKeyBytes := priv.PublicKey().Marshal()
h := crypto.SHA256.New()
magics.write(h)
writeString(h, hostKeyBytes)
writeString(h, kexInit.ClientPubKey)
writeString(h, kp.pub[:])
kInt := new(big.Int).SetBytes(secret[:])
K := make([]byte, intLength(kInt))
marshalInt(K, kInt)
h.Write(K)
H := h.Sum(nil)
sig, err := signAndMarshal(priv, rand, H)
if err != nil {
return nil, err
}
reply := kexECDHReplyMsg{
EphemeralPubKey: kp.pub[:],
HostKey: hostKeyBytes,
Signature: sig,
}
if err := c.writePacket(Marshal(&reply)); err != nil {
return nil, err
}
return &kexResult{
H: H,
K: K,
HostKey: hostKeyBytes,
Signature: sig,
Hash: crypto.SHA256,
}, nil
}

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modules/crypto/ssh/kex_test.go
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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
// Key exchange tests.
import (
"crypto/rand"
"reflect"
"testing"
)
func TestKexes(t *testing.T) {
type kexResultErr struct {
result *kexResult
err error
}
for name, kex := range kexAlgoMap {
a, b := memPipe()
s := make(chan kexResultErr, 1)
c := make(chan kexResultErr, 1)
var magics handshakeMagics
go func() {
r, e := kex.Client(a, rand.Reader, &magics)
a.Close()
c <- kexResultErr{r, e}
}()
go func() {
r, e := kex.Server(b, rand.Reader, &magics, testSigners["ecdsa"])
b.Close()
s <- kexResultErr{r, e}
}()
clientRes := <-c
serverRes := <-s
if clientRes.err != nil {
t.Errorf("client: %v", clientRes.err)
}
if serverRes.err != nil {
t.Errorf("server: %v", serverRes.err)
}
if !reflect.DeepEqual(clientRes.result, serverRes.result) {
t.Errorf("kex %q: mismatch %#v, %#v", name, clientRes.result, serverRes.result)
}
}
}

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modules/crypto/ssh/keys.go
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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"bytes"
"crypto"
"crypto/dsa"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rsa"
"crypto/x509"
"encoding/asn1"
"encoding/base64"
"encoding/pem"
"errors"
"fmt"
"io"
"math/big"
)
// These constants represent the algorithm names for key types supported by this
// package.
const (
KeyAlgoRSA = "ssh-rsa"
KeyAlgoDSA = "ssh-dss"
KeyAlgoECDSA256 = "ecdsa-sha2-nistp256"
KeyAlgoECDSA384 = "ecdsa-sha2-nistp384"
KeyAlgoECDSA521 = "ecdsa-sha2-nistp521"
)
// parsePubKey parses a public key of the given algorithm.
// Use ParsePublicKey for keys with prepended algorithm.
func parsePubKey(in []byte, algo string) (pubKey PublicKey, rest []byte, err error) {
switch algo {
case KeyAlgoRSA:
return parseRSA(in)
case KeyAlgoDSA:
return parseDSA(in)
case KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521:
return parseECDSA(in)
case CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, CertAlgoECDSA384v01, CertAlgoECDSA521v01:
cert, err := parseCert(in, certToPrivAlgo(algo))
if err != nil {
return nil, nil, err
}
return cert, nil, nil
}
return nil, nil, fmt.Errorf("ssh: unknown key algorithm: %v", err)
}
// parseAuthorizedKey parses a public key in OpenSSH authorized_keys format
// (see sshd(8) manual page) once the options and key type fields have been
// removed.
func parseAuthorizedKey(in []byte) (out PublicKey, comment string, err error) {
in = bytes.TrimSpace(in)
i := bytes.IndexAny(in, " \t")
if i == -1 {
i = len(in)
}
base64Key := in[:i]
key := make([]byte, base64.StdEncoding.DecodedLen(len(base64Key)))
n, err := base64.StdEncoding.Decode(key, base64Key)
if err != nil {
return nil, "", err
}
key = key[:n]
out, err = ParsePublicKey(key)
if err != nil {
return nil, "", err
}
comment = string(bytes.TrimSpace(in[i:]))
return out, comment, nil
}
// ParseAuthorizedKeys parses a public key from an authorized_keys
// file used in OpenSSH according to the sshd(8) manual page.
func ParseAuthorizedKey(in []byte) (out PublicKey, comment string, options []string, rest []byte, err error) {
for len(in) > 0 {
end := bytes.IndexByte(in, '\n')
if end != -1 {
rest = in[end+1:]
in = in[:end]
} else {
rest = nil
}
end = bytes.IndexByte(in, '\r')
if end != -1 {
in = in[:end]
}
in = bytes.TrimSpace(in)
if len(in) == 0 || in[0] == '#' {
in = rest
continue
}
i := bytes.IndexAny(in, " \t")
if i == -1 {
in = rest
continue
}
if out, comment, err = parseAuthorizedKey(in[i:]); err == nil {
return out, comment, options, rest, nil
}
// No key type recognised. Maybe there's an options field at
// the beginning.
var b byte
inQuote := false
var candidateOptions []string
optionStart := 0
for i, b = range in {
isEnd := !inQuote && (b == ' ' || b == '\t')
if (b == ',' && !inQuote) || isEnd {
if i-optionStart > 0 {
candidateOptions = append(candidateOptions, string(in[optionStart:i]))
}
optionStart = i + 1
}
if isEnd {
break
}
if b == '"' && (i == 0 || (i > 0 && in[i-1] != '\\')) {
inQuote = !inQuote
}
}
for i < len(in) && (in[i] == ' ' || in[i] == '\t') {
i++
}
if i == len(in) {
// Invalid line: unmatched quote
in = rest
continue
}
in = in[i:]
i = bytes.IndexAny(in, " \t")
if i == -1 {
in = rest
continue
}
if out, comment, err = parseAuthorizedKey(in[i:]); err == nil {
options = candidateOptions
return out, comment, options, rest, nil
}
in = rest
continue
}
return nil, "", nil, nil, errors.New("ssh: no key found")
}
// ParsePublicKey parses an SSH public key formatted for use in
// the SSH wire protocol according to RFC 4253, section 6.6.
func ParsePublicKey(in []byte) (out PublicKey, err error) {
algo, in, ok := parseString(in)
if !ok {
return nil, errShortRead
}
var rest []byte
out, rest, err = parsePubKey(in, string(algo))
if len(rest) > 0 {
return nil, errors.New("ssh: trailing junk in public key")
}
return out, err
}
// MarshalAuthorizedKey serializes key for inclusion in an OpenSSH
// authorized_keys file. The return value ends with newline.
func MarshalAuthorizedKey(key PublicKey) []byte {
b := &bytes.Buffer{}
b.WriteString(key.Type())
b.WriteByte(' ')
e := base64.NewEncoder(base64.StdEncoding, b)
e.Write(key.Marshal())
e.Close()
b.WriteByte('\n')
return b.Bytes()
}
// PublicKey is an abstraction of different types of public keys.
type PublicKey interface {
// Type returns the key's type, e.g. "ssh-rsa".
Type() string
// Marshal returns the serialized key data in SSH wire format,
// with the name prefix.
Marshal() []byte
// Verify that sig is a signature on the given data using this
// key. This function will hash the data appropriately first.
Verify(data []byte, sig *Signature) error
}
// A Signer can create signatures that verify against a public key.
type Signer interface {
// PublicKey returns an associated PublicKey instance.
PublicKey() PublicKey
// Sign returns raw signature for the given data. This method
// will apply the hash specified for the keytype to the data.
Sign(rand io.Reader, data []byte) (*Signature, error)
}
type rsaPublicKey rsa.PublicKey
func (r *rsaPublicKey) Type() string {
return "ssh-rsa"
}
// parseRSA parses an RSA key according to RFC 4253, section 6.6.
func parseRSA(in []byte) (out PublicKey, rest []byte, err error) {
var w struct {
E *big.Int
N *big.Int
Rest []byte `ssh:"rest"`
}
if err := Unmarshal(in, &w); err != nil {
return nil, nil, err
}
if w.E.BitLen() > 24 {
return nil, nil, errors.New("ssh: exponent too large")
}
e := w.E.Int64()
if e < 3 || e&1 == 0 {
return nil, nil, errors.New("ssh: incorrect exponent")
}
var key rsa.PublicKey
key.E = int(e)
key.N = w.N
return (*rsaPublicKey)(&key), w.Rest, nil
}
func (r *rsaPublicKey) Marshal() []byte {
e := new(big.Int).SetInt64(int64(r.E))
wirekey := struct {
Name string
E *big.Int
N *big.Int
}{
KeyAlgoRSA,
e,
r.N,
}
return Marshal(&wirekey)
}
func (r *rsaPublicKey) Verify(data []byte, sig *Signature) error {
if sig.Format != r.Type() {
return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, r.Type())
}
h := crypto.SHA1.New()
h.Write(data)
digest := h.Sum(nil)
return rsa.VerifyPKCS1v15((*rsa.PublicKey)(r), crypto.SHA1, digest, sig.Blob)
}
type rsaPrivateKey struct {
*rsa.PrivateKey
}
func (r *rsaPrivateKey) PublicKey() PublicKey {
return (*rsaPublicKey)(&r.PrivateKey.PublicKey)
}
func (r *rsaPrivateKey) Sign(rand io.Reader, data []byte) (*Signature, error) {
h := crypto.SHA1.New()
h.Write(data)
digest := h.Sum(nil)
blob, err := rsa.SignPKCS1v15(rand, r.PrivateKey, crypto.SHA1, digest)
if err != nil {
return nil, err
}
return &Signature{
Format: r.PublicKey().Type(),
Blob: blob,
}, nil
}
type dsaPublicKey dsa.PublicKey
func (r *dsaPublicKey) Type() string {
return "ssh-dss"
}
// parseDSA parses an DSA key according to RFC 4253, section 6.6.
func parseDSA(in []byte) (out PublicKey, rest []byte, err error) {
var w struct {
P, Q, G, Y *big.Int
Rest []byte `ssh:"rest"`
}
if err := Unmarshal(in, &w); err != nil {
return nil, nil, err
}
key := &dsaPublicKey{
Parameters: dsa.Parameters{
P: w.P,
Q: w.Q,
G: w.G,
},
Y: w.Y,
}
return key, w.Rest, nil
}
func (k *dsaPublicKey) Marshal() []byte {
w := struct {
Name string
P, Q, G, Y *big.Int
}{
k.Type(),
k.P,
k.Q,
k.G,
k.Y,
}
return Marshal(&w)
}
func (k *dsaPublicKey) Verify(data []byte, sig *Signature) error {
if sig.Format != k.Type() {
return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, k.Type())
}
h := crypto.SHA1.New()
h.Write(data)
digest := h.Sum(nil)
// Per RFC 4253, section 6.6,
// The value for 'dss_signature_blob' is encoded as a string containing
// r, followed by s (which are 160-bit integers, without lengths or
// padding, unsigned, and in network byte order).
// For DSS purposes, sig.Blob should be exactly 40 bytes in length.
if len(sig.Blob) != 40 {
return errors.New("ssh: DSA signature parse error")
}
r := new(big.Int).SetBytes(sig.Blob[:20])
s := new(big.Int).SetBytes(sig.Blob[20:])
if dsa.Verify((*dsa.PublicKey)(k), digest, r, s) {
return nil
}
return errors.New("ssh: signature did not verify")
}
type dsaPrivateKey struct {
*dsa.PrivateKey
}
func (k *dsaPrivateKey) PublicKey() PublicKey {
return (*dsaPublicKey)(&k.PrivateKey.PublicKey)
}
func (k *dsaPrivateKey) Sign(rand io.Reader, data []byte) (*Signature, error) {
h := crypto.SHA1.New()
h.Write(data)
digest := h.Sum(nil)
r, s, err := dsa.Sign(rand, k.PrivateKey, digest)
if err != nil {
return nil, err
}
sig := make([]byte, 40)
rb := r.Bytes()
sb := s.Bytes()
copy(sig[20-len(rb):20], rb)
copy(sig[40-len(sb):], sb)
return &Signature{
Format: k.PublicKey().Type(),
Blob: sig,
}, nil
}
type ecdsaPublicKey ecdsa.PublicKey
func (key *ecdsaPublicKey) Type() string {
return "ecdsa-sha2-" + key.nistID()
}
func (key *ecdsaPublicKey) nistID() string {
switch key.Params().BitSize {
case 256:
return "nistp256"
case 384:
return "nistp384"
case 521:
return "nistp521"
}
panic("ssh: unsupported ecdsa key size")
}
func supportedEllipticCurve(curve elliptic.Curve) bool {
return curve == elliptic.P256() || curve == elliptic.P384() || curve == elliptic.P521()
}
// ecHash returns the hash to match the given elliptic curve, see RFC
// 5656, section 6.2.1
func ecHash(curve elliptic.Curve) crypto.Hash {
bitSize := curve.Params().BitSize
switch {
case bitSize <= 256:
return crypto.SHA256
case bitSize <= 384:
return crypto.SHA384
}
return crypto.SHA512
}
// parseECDSA parses an ECDSA key according to RFC 5656, section 3.1.
func parseECDSA(in []byte) (out PublicKey, rest []byte, err error) {
var w struct {
Curve string
KeyBytes []byte
Rest []byte `ssh:"rest"`
}
if err := Unmarshal(in, &w); err != nil {
return nil, nil, err
}
key := new(ecdsa.PublicKey)
switch w.Curve {
case "nistp256":
key.Curve = elliptic.P256()
case "nistp384":
key.Curve = elliptic.P384()
case "nistp521":
key.Curve = elliptic.P521()
default:
return nil, nil, errors.New("ssh: unsupported curve")
}
key.X, key.Y = elliptic.Unmarshal(key.Curve, w.KeyBytes)
if key.X == nil || key.Y == nil {
return nil, nil, errors.New("ssh: invalid curve point")
}
return (*ecdsaPublicKey)(key), w.Rest, nil
}
func (key *ecdsaPublicKey) Marshal() []byte {
// See RFC 5656, section 3.1.
keyBytes := elliptic.Marshal(key.Curve, key.X, key.Y)
w := struct {
Name string
ID string
Key []byte
}{
key.Type(),
key.nistID(),
keyBytes,
}
return Marshal(&w)
}
func (key *ecdsaPublicKey) Verify(data []byte, sig *Signature) error {
if sig.Format != key.Type() {
return fmt.Errorf("ssh: signature type %s for key type %s", sig.Format, key.Type())
}
h := ecHash(key.Curve).New()
h.Write(data)
digest := h.Sum(nil)
// Per RFC 5656, section 3.1.2,
// The ecdsa_signature_blob value has the following specific encoding:
// mpint r
// mpint s
var ecSig struct {
R *big.Int
S *big.Int
}
if err := Unmarshal(sig.Blob, &ecSig); err != nil {
return err
}
if ecdsa.Verify((*ecdsa.PublicKey)(key), digest, ecSig.R, ecSig.S) {
return nil
}
return errors.New("ssh: signature did not verify")
}
type ecdsaPrivateKey struct {
*ecdsa.PrivateKey
}
func (k *ecdsaPrivateKey) PublicKey() PublicKey {
return (*ecdsaPublicKey)(&k.PrivateKey.PublicKey)
}
func (k *ecdsaPrivateKey) Sign(rand io.Reader, data []byte) (*Signature, error) {
h := ecHash(k.PrivateKey.PublicKey.Curve).New()
h.Write(data)
digest := h.Sum(nil)
r, s, err := ecdsa.Sign(rand, k.PrivateKey, digest)
if err != nil {
return nil, err
}
sig := make([]byte, intLength(r)+intLength(s))
rest := marshalInt(sig, r)
marshalInt(rest, s)
return &Signature{
Format: k.PublicKey().Type(),
Blob: sig,
}, nil
}
// NewSignerFromKey takes a pointer to rsa, dsa or ecdsa PrivateKey
// returns a corresponding Signer instance. EC keys should use P256,
// P384 or P521.
func NewSignerFromKey(k interface{}) (Signer, error) {
var sshKey Signer
switch t := k.(type) {
case *rsa.PrivateKey:
sshKey = &rsaPrivateKey{t}
case *dsa.PrivateKey:
sshKey = &dsaPrivateKey{t}
case *ecdsa.PrivateKey:
if !supportedEllipticCurve(t.Curve) {
return nil, errors.New("ssh: only P256, P384 and P521 EC keys are supported.")
}
sshKey = &ecdsaPrivateKey{t}
default:
return nil, fmt.Errorf("ssh: unsupported key type %T", k)
}
return sshKey, nil
}
// NewPublicKey takes a pointer to rsa, dsa or ecdsa PublicKey
// and returns a corresponding ssh PublicKey instance. EC keys should use P256, P384 or P521.
func NewPublicKey(k interface{}) (PublicKey, error) {
var sshKey PublicKey
switch t := k.(type) {
case *rsa.PublicKey:
sshKey = (*rsaPublicKey)(t)
case *ecdsa.PublicKey:
if !supportedEllipticCurve(t.Curve) {
return nil, errors.New("ssh: only P256, P384 and P521 EC keys are supported.")
}
sshKey = (*ecdsaPublicKey)(t)
case *dsa.PublicKey:
sshKey = (*dsaPublicKey)(t)
default:
return nil, fmt.Errorf("ssh: unsupported key type %T", k)
}
return sshKey, nil
}
// ParsePrivateKey returns a Signer from a PEM encoded private key. It supports
// the same keys as ParseRawPrivateKey.
func ParsePrivateKey(pemBytes []byte) (Signer, error) {
key, err := ParseRawPrivateKey(pemBytes)
if err != nil {
return nil, err
}
return NewSignerFromKey(key)
}
// ParseRawPrivateKey returns a private key from a PEM encoded private key. It
// supports RSA (PKCS#1), DSA (OpenSSL), and ECDSA private keys.
func ParseRawPrivateKey(pemBytes []byte) (interface{}, error) {
block, _ := pem.Decode(pemBytes)
if block == nil {
return nil, errors.New("ssh: no key found")
}
switch block.Type {
case "RSA PRIVATE KEY":
return x509.ParsePKCS1PrivateKey(block.Bytes)
case "EC PRIVATE KEY":
return x509.ParseECPrivateKey(block.Bytes)
case "DSA PRIVATE KEY":
return ParseDSAPrivateKey(block.Bytes)
default:
return nil, fmt.Errorf("ssh: unsupported key type %q", block.Type)
}
}
// ParseDSAPrivateKey returns a DSA private key from its ASN.1 DER encoding, as
// specified by the OpenSSL DSA man page.
func ParseDSAPrivateKey(der []byte) (*dsa.PrivateKey, error) {
var k struct {
Version int
P *big.Int
Q *big.Int
G *big.Int
Priv *big.Int
Pub *big.Int
}
rest, err := asn1.Unmarshal(der, &k)
if err != nil {
return nil, errors.New("ssh: failed to parse DSA key: " + err.Error())
}
if len(rest) > 0 {
return nil, errors.New("ssh: garbage after DSA key")
}
return &dsa.PrivateKey{
PublicKey: dsa.PublicKey{
Parameters: dsa.Parameters{
P: k.P,
Q: k.Q,
G: k.G,
},
Y: k.Priv,
},
X: k.Pub,
}, nil
}

306
modules/crypto/ssh/keys_test.go
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@ -0,0 +1,306 @@
// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"bytes"
"crypto/dsa"
"crypto/ecdsa"
"crypto/elliptic"
"crypto/rand"
"crypto/rsa"
"encoding/base64"
"fmt"
"reflect"
"strings"
"testing"
"github.com/gogits/gogs/modules/ssh/testdata"
)
func rawKey(pub PublicKey) interface{} {
switch k := pub.(type) {
case *rsaPublicKey:
return (*rsa.PublicKey)(k)
case *dsaPublicKey:
return (*dsa.PublicKey)(k)
case *ecdsaPublicKey:
return (*ecdsa.PublicKey)(k)
case *Certificate:
return k
}
panic("unknown key type")
}
func TestKeyMarshalParse(t *testing.T) {
for _, priv := range testSigners {
pub := priv.PublicKey()
roundtrip, err := ParsePublicKey(pub.Marshal())
if err != nil {
t.Errorf("ParsePublicKey(%T): %v", pub, err)
}
k1 := rawKey(pub)
k2 := rawKey(roundtrip)
if !reflect.DeepEqual(k1, k2) {
t.Errorf("got %#v in roundtrip, want %#v", k2, k1)
}
}
}
func TestUnsupportedCurves(t *testing.T) {
raw, err := ecdsa.GenerateKey(elliptic.P224(), rand.Reader)
if err != nil {
t.Fatalf("GenerateKey: %v", err)
}
if _, err = NewSignerFromKey(raw); err == nil || !strings.Contains(err.Error(), "only P256") {
t.Fatalf("NewPrivateKey should not succeed with P224, got: %v", err)
}
if _, err = NewPublicKey(&raw.PublicKey); err == nil || !strings.Contains(err.Error(), "only P256") {
t.Fatalf("NewPublicKey should not succeed with P224, got: %v", err)
}
}
func TestNewPublicKey(t *testing.T) {
for _, k := range testSigners {
raw := rawKey(k.PublicKey())
// Skip certificates, as NewPublicKey does not support them.
if _, ok := raw.(*Certificate); ok {
continue
}
pub, err := NewPublicKey(raw)
if err != nil {
t.Errorf("NewPublicKey(%#v): %v", raw, err)
}
if !reflect.DeepEqual(k.PublicKey(), pub) {
t.Errorf("NewPublicKey(%#v) = %#v, want %#v", raw, pub, k.PublicKey())
}
}
}
func TestKeySignVerify(t *testing.T) {
for _, priv := range testSigners {
pub := priv.PublicKey()
data := []byte("sign me")
sig, err := priv.Sign(rand.Reader, data)
if err != nil {
t.Fatalf("Sign(%T): %v", priv, err)
}
if err := pub.Verify(data, sig); err != nil {
t.Errorf("publicKey.Verify(%T): %v", priv, err)
}
sig.Blob[5]++
if err := pub.Verify(data, sig); err == nil {
t.Errorf("publicKey.Verify on broken sig did not fail")
}
}
}
func TestParseRSAPrivateKey(t *testing.T) {
key := testPrivateKeys["rsa"]
rsa, ok := key.(*rsa.PrivateKey)
if !ok {
t.Fatalf("got %T, want *rsa.PrivateKey", rsa)
}
if err := rsa.Validate(); err != nil {
t.Errorf("Validate: %v", err)
}
}
func TestParseECPrivateKey(t *testing.T) {
key := testPrivateKeys["ecdsa"]
ecKey, ok := key.(*ecdsa.PrivateKey)
if !ok {
t.Fatalf("got %T, want *ecdsa.PrivateKey", ecKey)
}
if !validateECPublicKey(ecKey.Curve, ecKey.X, ecKey.Y) {
t.Fatalf("public key does not validate.")
}
}
func TestParseDSA(t *testing.T) {
// We actually exercise the ParsePrivateKey codepath here, as opposed to
// using the ParseRawPrivateKey+NewSignerFromKey path that testdata_test.go
// uses.
s, err := ParsePrivateKey(testdata.PEMBytes["dsa"])
if err != nil {
t.Fatalf("ParsePrivateKey returned error: %s", err)
}
data := []byte("sign me")
sig, err := s.Sign(rand.Reader, data)
if err != nil {
t.Fatalf("dsa.Sign: %v", err)
}
if err := s.PublicKey().Verify(data, sig); err != nil {
t.Errorf("Verify failed: %v", err)
}
}
// Tests for authorized_keys parsing.
// getTestKey returns a public key, and its base64 encoding.
func getTestKey() (PublicKey, string) {
k := testPublicKeys["rsa"]
b := &bytes.Buffer{}
e := base64.NewEncoder(base64.StdEncoding, b)
e.Write(k.Marshal())
e.Close()
return k, b.String()
}
func TestMarshalParsePublicKey(t *testing.T) {
pub, pubSerialized := getTestKey()
line := fmt.Sprintf("%s %s user@host", pub.Type(), pubSerialized)
authKeys := MarshalAuthorizedKey(pub)
actualFields := strings.Fields(string(authKeys))
if len(actualFields) == 0 {
t.Fatalf("failed authKeys: %v", authKeys)
}
// drop the comment
expectedFields := strings.Fields(line)[0:2]
if !reflect.DeepEqual(actualFields, expectedFields) {
t.Errorf("got %v, expected %v", actualFields, expectedFields)
}
actPub, _, _, _, err := ParseAuthorizedKey([]byte(line))
if err != nil {
t.Fatalf("cannot parse %v: %v", line, err)
}
if !reflect.DeepEqual(actPub, pub) {
t.Errorf("got %v, expected %v", actPub, pub)
}
}
type authResult struct {
pubKey PublicKey
options []string
comments string
rest string
ok bool
}
func testAuthorizedKeys(t *testing.T, authKeys []byte, expected []authResult) {
rest := authKeys
var values []authResult
for len(rest) > 0 {
var r authResult
var err error
r.pubKey, r.comments, r.options, rest, err = ParseAuthorizedKey(rest)
r.ok = (err == nil)
t.Log(err)
r.rest = string(rest)
values = append(values, r)
}
if !reflect.DeepEqual(values, expected) {
t.Errorf("got %#v, expected %#v", values, expected)
}
}
func TestAuthorizedKeyBasic(t *testing.T) {
pub, pubSerialized := getTestKey()
line := "ssh-rsa " + pubSerialized + " user@host"
testAuthorizedKeys(t, []byte(line),
[]authResult{
{pub, nil, "user@host", "", true},
})
}
func TestAuth(t *testing.T) {
pub, pubSerialized := getTestKey()
authWithOptions := []string{
`# comments to ignore before any keys...`,
``,
`env="HOME=/home/root",no-port-forwarding ssh-rsa ` + pubSerialized + ` user@host`,
`# comments to ignore, along with a blank line`,
``,
`env="HOME=/home/root2" ssh-rsa ` + pubSerialized + ` user2@host2`,
``,
`# more comments, plus a invalid entry`,
`ssh-rsa data-that-will-not-parse user@host3`,
}
for _, eol := range []string{"\n", "\r\n"} {
authOptions := strings.Join(authWithOptions, eol)
rest2 := strings.Join(authWithOptions[3:], eol)
rest3 := strings.Join(authWithOptions[6:], eol)
testAuthorizedKeys(t, []byte(authOptions), []authResult{
{pub, []string{`env="HOME=/home/root"`, "no-port-forwarding"}, "user@host", rest2, true},
{pub, []string{`env="HOME=/home/root2"`}, "user2@host2", rest3, true},
{nil, nil, "", "", false},
})
}
}
func TestAuthWithQuotedSpaceInEnv(t *testing.T) {
pub, pubSerialized := getTestKey()
authWithQuotedSpaceInEnv := []byte(`env="HOME=/home/root dir",no-port-forwarding ssh-rsa ` + pubSerialized + ` user@host`)
testAuthorizedKeys(t, []byte(authWithQuotedSpaceInEnv), []authResult{
{pub, []string{`env="HOME=/home/root dir"`, "no-port-forwarding"}, "user@host", "", true},
})
}
func TestAuthWithQuotedCommaInEnv(t *testing.T) {
pub, pubSerialized := getTestKey()
authWithQuotedCommaInEnv := []byte(`env="HOME=/home/root,dir",no-port-forwarding ssh-rsa ` + pubSerialized + ` user@host`)
testAuthorizedKeys(t, []byte(authWithQuotedCommaInEnv), []authResult{
{pub, []string{`env="HOME=/home/root,dir"`, "no-port-forwarding"}, "user@host", "", true},
})
}
func TestAuthWithQuotedQuoteInEnv(t *testing.T) {
pub, pubSerialized := getTestKey()
authWithQuotedQuoteInEnv := []byte(`env="HOME=/home/\"root dir",no-port-forwarding` + "\t" + `ssh-rsa` + "\t" + pubSerialized + ` user@host`)
authWithDoubleQuotedQuote := []byte(`no-port-forwarding,env="HOME=/home/ \"root dir\"" ssh-rsa ` + pubSerialized + "\t" + `user@host`)
testAuthorizedKeys(t, []byte(authWithQuotedQuoteInEnv), []authResult{
{pub, []string{`env="HOME=/home/\"root dir"`, "no-port-forwarding"}, "user@host", "", true},
})
testAuthorizedKeys(t, []byte(authWithDoubleQuotedQuote), []authResult{
{pub, []string{"no-port-forwarding", `env="HOME=/home/ \"root dir\""`}, "user@host", "", true},
})
}
func TestAuthWithInvalidSpace(t *testing.T) {
_, pubSerialized := getTestKey()
authWithInvalidSpace := []byte(`env="HOME=/home/root dir", no-port-forwarding ssh-rsa ` + pubSerialized + ` user@host
#more to follow but still no valid keys`)
testAuthorizedKeys(t, []byte(authWithInvalidSpace), []authResult{
{nil, nil, "", "", false},
})
}
func TestAuthWithMissingQuote(t *testing.T) {
pub, pubSerialized := getTestKey()
authWithMissingQuote := []byte(`env="HOME=/home/root,no-port-forwarding ssh-rsa ` + pubSerialized + ` user@host
env="HOME=/home/root",shared-control ssh-rsa ` + pubSerialized + ` user@host`)
testAuthorizedKeys(t, []byte(authWithMissingQuote), []authResult{
{pub, []string{`env="HOME=/home/root"`, `shared-control`}, "user@host", "", true},
})
}
func TestInvalidEntry(t *testing.T) {
authInvalid := []byte(`ssh-rsa`)
_, _, _, _, err := ParseAuthorizedKey(authInvalid)
if err == nil {
t.Errorf("got valid entry for %q", authInvalid)
}
}

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modules/crypto/ssh/mac.go
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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
// Message authentication support
import (
"crypto/hmac"
"crypto/sha1"
"crypto/sha256"
"hash"
)
type macMode struct {
keySize int
new func(key []byte) hash.Hash
}
// truncatingMAC wraps around a hash.Hash and truncates the output digest to
// a given size.
type truncatingMAC struct {
length int
hmac hash.Hash
}
func (t truncatingMAC) Write(data []byte) (int, error) {
return t.hmac.Write(data)
}
func (t truncatingMAC) Sum(in []byte) []byte {
out := t.hmac.Sum(in)
return out[:len(in)+t.length]
}
func (t truncatingMAC) Reset() {
t.hmac.Reset()
}
func (t truncatingMAC) Size() int {
return t.length
}
func (t truncatingMAC) BlockSize() int { return t.hmac.BlockSize() }
var macModes = map[string]*macMode{
"hmac-sha2-256": {32, func(key []byte) hash.Hash {
return hmac.New(sha256.New, key)
}},
"hmac-sha1": {20, func(key []byte) hash.Hash {
return hmac.New(sha1.New, key)
}},
"hmac-sha1-96": {20, func(key []byte) hash.Hash {
return truncatingMAC{12, hmac.New(sha1.New, key)}
}},
}

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modules/crypto/ssh/mempipe_test.go
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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"io"
"sync"
"testing"
)
// An in-memory packetConn. It is safe to call Close and writePacket
// from different goroutines.
type memTransport struct {
eof bool
pending [][]byte
write *memTransport
sync.Mutex
*sync.Cond
}
func (t *memTransport) readPacket() ([]byte, error) {
t.Lock()
defer t.Unlock()
for {
if len(t.pending) > 0 {
r := t.pending[0]
t.pending = t.pending[1:]
return r, nil
}
if t.eof {
return nil, io.EOF
}
t.Cond.Wait()
}
}
func (t *memTransport) closeSelf() error {
t.Lock()
defer t.Unlock()
if t.eof {
return io.EOF
}
t.eof = true
t.Cond.Broadcast()
return nil
}
func (t *memTransport) Close() error {
err := t.write.closeSelf()
t.closeSelf()
return err
}
func (t *memTransport) writePacket(p []byte) error {
t.write.Lock()
defer t.write.Unlock()
if t.write.eof {
return io.EOF
}
c := make([]byte, len(p))
copy(c, p)
t.write.pending = append(t.write.pending, c)
t.write.Cond.Signal()
return nil
}
func memPipe() (a, b packetConn) {
t1 := memTransport{}
t2 := memTransport{}
t1.write = &t2
t2.write = &t1
t1.Cond = sync.NewCond(&t1.Mutex)
t2.Cond = sync.NewCond(&t2.Mutex)
return &t1, &t2
}
func TestMemPipe(t *testing.T) {
a, b := memPipe()
if err := a.writePacket([]byte{42}); err != nil {
t.Fatalf("writePacket: %v", err)
}
if err := a.Close(); err != nil {
t.Fatal("Close: ", err)
}
p, err := b.readPacket()
if err != nil {
t.Fatal("readPacket: ", err)
}
if len(p) != 1 || p[0] != 42 {
t.Fatalf("got %v, want {42}", p)
}
p, err = b.readPacket()
if err != io.EOF {
t.Fatalf("got %v, %v, want EOF", p, err)
}
}
func TestDoubleClose(t *testing.T) {
a, _ := memPipe()
err := a.Close()
if err != nil {
t.Errorf("Close: %v", err)
}
err = a.Close()
if err != io.EOF {
t.Errorf("expect EOF on double close.")
}
}

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modules/crypto/ssh/messages.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"bytes"
"encoding/binary"
"errors"
"fmt"
"io"
"math/big"
"reflect"
"strconv"
)
// These are SSH message type numbers. They are scattered around several
// documents but many were taken from [SSH-PARAMETERS].
const (
msgIgnore = 2
msgUnimplemented = 3
msgDebug = 4
msgNewKeys = 21
// Standard authentication messages
msgUserAuthSuccess = 52
msgUserAuthBanner = 53
)
// SSH messages:
//
// These structures mirror the wire format of the corresponding SSH messages.
// They are marshaled using reflection with the marshal and unmarshal functions
// in this file. The only wrinkle is that a final member of type []byte with a
// ssh tag of "rest" receives the remainder of a packet when unmarshaling.
// See RFC 4253, section 11.1.
const msgDisconnect = 1
// disconnectMsg is the message that signals a disconnect. It is also
// the error type returned from mux.Wait()
type disconnectMsg struct {
Reason uint32 `sshtype:"1"`
Message string
Language string
}
func (d *disconnectMsg) Error() string {
return fmt.Sprintf("ssh: disconnect reason %d: %s", d.Reason, d.Message)
}
// See RFC 4253, section 7.1.
const msgKexInit = 20
type kexInitMsg struct {
Cookie [16]byte `sshtype:"20"`
KexAlgos []string
ServerHostKeyAlgos []string
CiphersClientServer []string
CiphersServerClient []string
MACsClientServer []string
MACsServerClient []string
CompressionClientServer []string
CompressionServerClient []string
LanguagesClientServer []string
LanguagesServerClient []string
FirstKexFollows bool
Reserved uint32
}
// See RFC 4253, section 8.
// Diffie-Helman
const msgKexDHInit = 30
type kexDHInitMsg struct {
X *big.Int `sshtype:"30"`
}
const msgKexECDHInit = 30
type kexECDHInitMsg struct {
ClientPubKey []byte `sshtype:"30"`
}
const msgKexECDHReply = 31
type kexECDHReplyMsg struct {
HostKey []byte `sshtype:"31"`
EphemeralPubKey []byte
Signature []byte
}
const msgKexDHReply = 31
type kexDHReplyMsg struct {
HostKey []byte `sshtype:"31"`
Y *big.Int
Signature []byte
}
// See RFC 4253, section 10.
const msgServiceRequest = 5
type serviceRequestMsg struct {
Service string `sshtype:"5"`
}
// See RFC 4253, section 10.
const msgServiceAccept = 6
type serviceAcceptMsg struct {
Service string `sshtype:"6"`
}
// See RFC 4252, section 5.
const msgUserAuthRequest = 50
type userAuthRequestMsg struct {
User string `sshtype:"50"`
Service string
Method string
Payload []byte `ssh:"rest"`
}
// See RFC 4252, section 5.1
const msgUserAuthFailure = 51
type userAuthFailureMsg struct {
Methods []string `sshtype:"51"`
PartialSuccess bool
}
// See RFC 4256, section 3.2
const msgUserAuthInfoRequest = 60
const msgUserAuthInfoResponse = 61
type userAuthInfoRequestMsg struct {
User string `sshtype:"60"`
Instruction string
DeprecatedLanguage string
NumPrompts uint32
Prompts []byte `ssh:"rest"`
}
// See RFC 4254, section 5.1.
const msgChannelOpen = 90
type channelOpenMsg struct {
ChanType string `sshtype:"90"`
PeersId uint32
PeersWindow uint32
MaxPacketSize uint32
TypeSpecificData []byte `ssh:"rest"`
}
const msgChannelExtendedData = 95
const msgChannelData = 94
// See RFC 4254, section 5.1.
const msgChannelOpenConfirm = 91
type channelOpenConfirmMsg struct {
PeersId uint32 `sshtype:"91"`
MyId uint32
MyWindow uint32
MaxPacketSize uint32
TypeSpecificData []byte `ssh:"rest"`
}
// See RFC 4254, section 5.1.
const msgChannelOpenFailure = 92
type channelOpenFailureMsg struct {
PeersId uint32 `sshtype:"92"`
Reason RejectionReason
Message string
Language string
}
const msgChannelRequest = 98
type channelRequestMsg struct {
PeersId uint32 `sshtype:"98"`
Request string
WantReply bool
RequestSpecificData []byte `ssh:"rest"`
}
// See RFC 4254, section 5.4.
const msgChannelSuccess = 99
type channelRequestSuccessMsg struct {
PeersId uint32 `sshtype:"99"`
}
// See RFC 4254, section 5.4.
const msgChannelFailure = 100
type channelRequestFailureMsg struct {
PeersId uint32 `sshtype:"100"`
}
// See RFC 4254, section 5.3
const msgChannelClose = 97
type channelCloseMsg struct {
PeersId uint32 `sshtype:"97"`
}
// See RFC 4254, section 5.3
const msgChannelEOF = 96
type channelEOFMsg struct {
PeersId uint32 `sshtype:"96"`
}
// See RFC 4254, section 4
const msgGlobalRequest = 80
type globalRequestMsg struct {
Type string `sshtype:"80"`
WantReply bool
Data []byte `ssh:"rest"`
}
// See RFC 4254, section 4
const msgRequestSuccess = 81
type globalRequestSuccessMsg struct {
Data []byte `ssh:"rest" sshtype:"81"`
}
// See RFC 4254, section 4
const msgRequestFailure = 82
type globalRequestFailureMsg struct {
Data []byte `ssh:"rest" sshtype:"82"`
}
// See RFC 4254, section 5.2
const msgChannelWindowAdjust = 93
type windowAdjustMsg struct {
PeersId uint32 `sshtype:"93"`
AdditionalBytes uint32
}
// See RFC 4252, section 7
const msgUserAuthPubKeyOk = 60
type userAuthPubKeyOkMsg struct {
Algo string `sshtype:"60"`
PubKey []byte
}
// typeTag returns the type byte for the given type. The type should
// be struct.
func typeTag(structType reflect.Type) byte {
var tag byte
var tagStr string
tagStr = structType.Field(0).Tag.Get("sshtype")
i, err := strconv.Atoi(tagStr)
if err == nil {
tag = byte(i)
}
return tag
}
func fieldError(t reflect.Type, field int, problem string) error {
if problem != "" {
problem = ": " + problem
}
return fmt.Errorf("ssh: unmarshal error for field %s of type %s%s", t.Field(field).Name, t.Name(), problem)
}
var errShortRead = errors.New("ssh: short read")
// Unmarshal parses data in SSH wire format into a structure. The out
// argument should be a pointer to struct. If the first member of the
// struct has the "sshtype" tag set to a number in decimal, the packet
// must start that number. In case of error, Unmarshal returns a
// ParseError or UnexpectedMessageError.
func Unmarshal(data []byte, out interface{}) error {
v := reflect.ValueOf(out).Elem()
structType := v.Type()
expectedType := typeTag(structType)
if len(data) == 0 {
return parseError(expectedType)
}
if expectedType > 0 {
if data[0] != expectedType {
return unexpectedMessageError(expectedType, data[0])
}
data = data[1:]
}
var ok bool
for i := 0; i < v.NumField(); i++ {
field := v.Field(i)
t := field.Type()
switch t.Kind() {
case reflect.Bool:
if len(data) < 1 {
return errShortRead
}
field.SetBool(data[0] != 0)
data = data[1:]
case reflect.Array:
if t.Elem().Kind() != reflect.Uint8 {
return fieldError(structType, i, "array of unsupported type")
}
if len(data) < t.Len() {
return errShortRead
}
for j, n := 0, t.Len(); j < n; j++ {
field.Index(j).Set(reflect.ValueOf(data[j]))
}
data = data[t.Len():]
case reflect.Uint64:
var u64 uint64
if u64, data, ok = parseUint64(data); !ok {
return errShortRead
}
field.SetUint(u64)
case reflect.Uint32:
var u32 uint32
if u32, data, ok = parseUint32(data); !ok {
return errShortRead
}
field.SetUint(uint64(u32))
case reflect.Uint8:
if len(data) < 1 {
return errShortRead
}
field.SetUint(uint64(data[0]))
data = data[1:]
case reflect.String:
var s []byte
if s, data, ok = parseString(data); !ok {
return fieldError(structType, i, "")
}
field.SetString(string(s))
case reflect.Slice:
switch t.Elem().Kind() {
case reflect.Uint8:
if structType.Field(i).Tag.Get("ssh") == "rest" {
field.Set(reflect.ValueOf(data))
data = nil
} else {
var s []byte
if s, data, ok = parseString(data); !ok {
return errShortRead
}
field.Set(reflect.ValueOf(s))
}
case reflect.String:
var nl []string
if nl, data, ok = parseNameList(data); !ok {
return errShortRead
}
field.Set(reflect.ValueOf(nl))
default:
return fieldError(structType, i, "slice of unsupported type")
}
case reflect.Ptr:
if t == bigIntType {
var n *big.Int
if n, data, ok = parseInt(data); !ok {
return errShortRead
}
field.Set(reflect.ValueOf(n))
} else {
return fieldError(structType, i, "pointer to unsupported type")
}
default:
return fieldError(structType, i, "unsupported type")
}
}
if len(data) != 0 {
return parseError(expectedType)
}
return nil
}
// Marshal serializes the message in msg to SSH wire format. The msg
// argument should be a struct or pointer to struct. If the first
// member has the "sshtype" tag set to a number in decimal, that
// number is prepended to the result. If the last of member has the
// "ssh" tag set to "rest", its contents are appended to the output.
func Marshal(msg interface{}) []byte {
out := make([]byte, 0, 64)
return marshalStruct(out, msg)
}
func marshalStruct(out []byte, msg interface{}) []byte {
v := reflect.Indirect(reflect.ValueOf(msg))
msgType := typeTag(v.Type())
if msgType > 0 {
out = append(out, msgType)
}
for i, n := 0, v.NumField(); i < n; i++ {
field := v.Field(i)
switch t := field.Type(); t.Kind() {
case reflect.Bool:
var v uint8
if field.Bool() {
v = 1
}
out = append(out, v)
case reflect.Array:
if t.Elem().Kind() != reflect.Uint8 {
panic(fmt.Sprintf("array of non-uint8 in field %d: %T", i, field.Interface()))
}
for j, l := 0, t.Len(); j < l; j++ {
out = append(out, uint8(field.Index(j).Uint()))
}
case reflect.Uint32:
out = appendU32(out, uint32(field.Uint()))
case reflect.Uint64:
out = appendU64(out, uint64(field.Uint()))
case reflect.Uint8:
out = append(out, uint8(field.Uint()))
case reflect.String:
s := field.String()
out = appendInt(out, len(s))
out = append(out, s...)
case reflect.Slice:
switch t.Elem().Kind() {
case reflect.Uint8:
if v.Type().Field(i).Tag.Get("ssh") != "rest" {
out = appendInt(out, field.Len())
}
out = append(out, field.Bytes()...)
case reflect.String:
offset := len(out)
out = appendU32(out, 0)
if n := field.Len(); n > 0 {
for j := 0; j < n; j++ {
f := field.Index(j)
if j != 0 {
out = append(out, ',')
}
out = append(out, f.String()...)
}
// overwrite length value
binary.BigEndian.PutUint32(out[offset:], uint32(len(out)-offset-4))
}
default:
panic(fmt.Sprintf("slice of unknown type in field %d: %T", i, field.Interface()))
}
case reflect.Ptr:
if t == bigIntType {
var n *big.Int
nValue := reflect.ValueOf(&n)
nValue.Elem().Set(field)
needed := intLength(n)
oldLength := len(out)
if cap(out)-len(out) < needed {
newOut := make([]byte, len(out), 2*(len(out)+needed))
copy(newOut, out)
out = newOut
}
out = out[:oldLength+needed]
marshalInt(out[oldLength:], n)
} else {
panic(fmt.Sprintf("pointer to unknown type in field %d: %T", i, field.Interface()))
}
}
}
return out
}
var bigOne = big.NewInt(1)
func parseString(in []byte) (out, rest []byte, ok bool) {
if len(in) < 4 {
return
}
length := binary.BigEndian.Uint32(in)
in = in[4:]
if uint32(len(in)) < length {
return
}
out = in[:length]
rest = in[length:]
ok = true
return
}
var (
comma = []byte{','}
emptyNameList = []string{}
)
func parseNameList(in []byte) (out []string, rest []byte, ok bool) {
contents, rest, ok := parseString(in)
if !ok {
return
}
if len(contents) == 0 {
out = emptyNameList
return
}
parts := bytes.Split(contents, comma)
out = make([]string, len(parts))
for i, part := range parts {
out[i] = string(part)
}
return
}
func parseInt(in []byte) (out *big.Int, rest []byte, ok bool) {
contents, rest, ok := parseString(in)
if !ok {
return
}
out = new(big.Int)
if len(contents) > 0 && contents[0]&0x80 == 0x80 {
// This is a negative number
notBytes := make([]byte, len(contents))
for i := range notBytes {
notBytes[i] = ^contents[i]
}
out.SetBytes(notBytes)
out.Add(out, bigOne)
out.Neg(out)
} else {
// Positive number
out.SetBytes(contents)
}
ok = true
return
}
func parseUint32(in []byte) (uint32, []byte, bool) {
if len(in) < 4 {
return 0, nil, false
}
return binary.BigEndian.Uint32(in), in[4:], true
}
func parseUint64(in []byte) (uint64, []byte, bool) {
if len(in) < 8 {
return 0, nil, false
}
return binary.BigEndian.Uint64(in), in[8:], true
}
func intLength(n *big.Int) int {
length := 4 /* length bytes */
if n.Sign() < 0 {
nMinus1 := new(big.Int).Neg(n)
nMinus1.Sub(nMinus1, bigOne)
bitLen := nMinus1.BitLen()
if bitLen%8 == 0 {
// The number will need 0xff padding
length++
}
length += (bitLen + 7) / 8
} else if n.Sign() == 0 {
// A zero is the zero length string
} else {
bitLen := n.BitLen()
if bitLen%8 == 0 {
// The number will need 0x00 padding
length++
}
length += (bitLen + 7) / 8
}
return length
}
func marshalUint32(to []byte, n uint32) []byte {
binary.BigEndian.PutUint32(to, n)
return to[4:]
}
func marshalUint64(to []byte, n uint64) []byte {
binary.BigEndian.PutUint64(to, n)
return to[8:]
}
func marshalInt(to []byte, n *big.Int) []byte {
lengthBytes := to
to = to[4:]
length := 0
if n.Sign() < 0 {
// A negative number has to be converted to two's-complement
// form. So we'll subtract 1 and invert. If the
// most-significant-bit isn't set then we'll need to pad the
// beginning with 0xff in order to keep the number negative.
nMinus1 := new(big.Int).Neg(n)
nMinus1.Sub(nMinus1, bigOne)
bytes := nMinus1.Bytes()
for i := range bytes {
bytes[i] ^= 0xff
}
if len(bytes) == 0 || bytes[0]&0x80 == 0 {
to[0] = 0xff
to = to[1:]
length++
}
nBytes := copy(to, bytes)
to = to[nBytes:]
length += nBytes
} else if n.Sign() == 0 {
// A zero is the zero length string
} else {
bytes := n.Bytes()
if len(bytes) > 0 && bytes[0]&0x80 != 0 {
// We'll have to pad this with a 0x00 in order to
// stop it looking like a negative number.
to[0] = 0
to = to[1:]
length++
}
nBytes := copy(to, bytes)
to = to[nBytes:]
length += nBytes
}
lengthBytes[0] = byte(length >> 24)
lengthBytes[1] = byte(length >> 16)
lengthBytes[2] = byte(length >> 8)
lengthBytes[3] = byte(length)
return to
}
func writeInt(w io.Writer, n *big.Int) {
length := intLength(n)
buf := make([]byte, length)
marshalInt(buf, n)
w.Write(buf)
}
func writeString(w io.Writer, s []byte) {
var lengthBytes [4]byte
lengthBytes[0] = byte(len(s) >> 24)
lengthBytes[1] = byte(len(s) >> 16)
lengthBytes[2] = byte(len(s) >> 8)
lengthBytes[3] = byte(len(s))
w.Write(lengthBytes[:])
w.Write(s)
}
func stringLength(n int) int {
return 4 + n
}
func marshalString(to []byte, s []byte) []byte {
to[0] = byte(len(s) >> 24)
to[1] = byte(len(s) >> 16)
to[2] = byte(len(s) >> 8)
to[3] = byte(len(s))
to = to[4:]
copy(to, s)
return to[len(s):]
}
var bigIntType = reflect.TypeOf((*big.Int)(nil))
// Decode a packet into its corresponding message.
func decode(packet []byte) (interface{}, error) {
var msg interface{}
switch packet[0] {
case msgDisconnect:
msg = new(disconnectMsg)
case msgServiceRequest:
msg = new(serviceRequestMsg)
case msgServiceAccept:
msg = new(serviceAcceptMsg)
case msgKexInit:
msg = new(kexInitMsg)
case msgKexDHInit:
msg = new(kexDHInitMsg)
case msgKexDHReply:
msg = new(kexDHReplyMsg)
case msgUserAuthRequest:
msg = new(userAuthRequestMsg)
case msgUserAuthFailure:
msg = new(userAuthFailureMsg)
case msgUserAuthPubKeyOk:
msg = new(userAuthPubKeyOkMsg)
case msgGlobalRequest:
msg = new(globalRequestMsg)
case msgRequestSuccess:
msg = new(globalRequestSuccessMsg)
case msgRequestFailure:
msg = new(globalRequestFailureMsg)
case msgChannelOpen:
msg = new(channelOpenMsg)
case msgChannelOpenConfirm:
msg = new(channelOpenConfirmMsg)
case msgChannelOpenFailure:
msg = new(channelOpenFailureMsg)
case msgChannelWindowAdjust:
msg = new(windowAdjustMsg)
case msgChannelEOF:
msg = new(channelEOFMsg)
case msgChannelClose:
msg = new(channelCloseMsg)
case msgChannelRequest:
msg = new(channelRequestMsg)
case msgChannelSuccess:
msg = new(channelRequestSuccessMsg)
case msgChannelFailure:
msg = new(channelRequestFailureMsg)
default:
return nil, unexpectedMessageError(0, packet[0])
}
if err := Unmarshal(packet, msg); err != nil {
return nil, err
}
return msg, nil
}

254
modules/crypto/ssh/messages_test.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"bytes"
"math/big"
"math/rand"
"reflect"
"testing"
"testing/quick"
)
var intLengthTests = []struct {
val, length int
}{
{0, 4 + 0},
{1, 4 + 1},
{127, 4 + 1},
{128, 4 + 2},
{-1, 4 + 1},
}
func TestIntLength(t *testing.T) {
for _, test := range intLengthTests {
v := new(big.Int).SetInt64(int64(test.val))
length := intLength(v)
if length != test.length {
t.Errorf("For %d, got length %d but expected %d", test.val, length, test.length)
}
}
}
type msgAllTypes struct {
Bool bool `sshtype:"21"`
Array [16]byte
Uint64 uint64
Uint32 uint32
Uint8 uint8
String string
Strings []string
Bytes []byte
Int *big.Int
Rest []byte `ssh:"rest"`
}
func (t *msgAllTypes) Generate(rand *rand.Rand, size int) reflect.Value {
m := &msgAllTypes{}
m.Bool = rand.Intn(2) == 1
randomBytes(m.Array[:], rand)
m.Uint64 = uint64(rand.Int63n(1<<63 - 1))
m.Uint32 = uint32(rand.Intn((1 << 31) - 1))
m.Uint8 = uint8(rand.Intn(1 << 8))
m.String = string(m.Array[:])
m.Strings = randomNameList(rand)
m.Bytes = m.Array[:]
m.Int = randomInt(rand)
m.Rest = m.Array[:]
return reflect.ValueOf(m)
}
func TestMarshalUnmarshal(t *testing.T) {
rand := rand.New(rand.NewSource(0))
iface := &msgAllTypes{}
ty := reflect.ValueOf(iface).Type()
n := 100
if testing.Short() {
n = 5
}
for j := 0; j < n; j++ {
v, ok := quick.Value(ty, rand)
if !ok {
t.Errorf("failed to create value")
break
}
m1 := v.Elem().Interface()
m2 := iface
marshaled := Marshal(m1)
if err := Unmarshal(marshaled, m2); err != nil {
t.Errorf("Unmarshal %#v: %s", m1, err)
break
}
if !reflect.DeepEqual(v.Interface(), m2) {
t.Errorf("got: %#v\nwant:%#v\n%x", m2, m1, marshaled)
break
}
}
}
func TestUnmarshalEmptyPacket(t *testing.T) {
var b []byte
var m channelRequestSuccessMsg
if err := Unmarshal(b, &m); err == nil {
t.Fatalf("unmarshal of empty slice succeeded")
}
}
func TestUnmarshalUnexpectedPacket(t *testing.T) {
type S struct {
I uint32 `sshtype:"43"`
S string
B bool
}
s := S{11, "hello", true}
packet := Marshal(s)
packet[0] = 42
roundtrip := S{}
err := Unmarshal(packet, &roundtrip)
if err == nil {
t.Fatal("expected error, not nil")
}
}
func TestMarshalPtr(t *testing.T) {
s := struct {
S string
}{"hello"}
m1 := Marshal(s)
m2 := Marshal(&s)
if !bytes.Equal(m1, m2) {
t.Errorf("got %q, want %q for marshaled pointer", m2, m1)
}
}
func TestBareMarshalUnmarshal(t *testing.T) {
type S struct {
I uint32
S string
B bool
}
s := S{42, "hello", true}
packet := Marshal(s)
roundtrip := S{}
Unmarshal(packet, &roundtrip)
if !reflect.DeepEqual(s, roundtrip) {
t.Errorf("got %#v, want %#v", roundtrip, s)
}
}
func TestBareMarshal(t *testing.T) {
type S2 struct {
I uint32
}
s := S2{42}
packet := Marshal(s)
i, rest, ok := parseUint32(packet)
if len(rest) > 0 || !ok {
t.Errorf("parseInt(%q): parse error", packet)
}
if i != s.I {
t.Errorf("got %d, want %d", i, s.I)
}
}
func TestUnmarshalShortKexInitPacket(t *testing.T) {
// This used to panic.
// Issue 11348
packet := []byte{0x14, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0x30, 0xff, 0xff, 0xff, 0xff}
kim := &kexInitMsg{}
if err := Unmarshal(packet, kim); err == nil {
t.Error("truncated packet unmarshaled without error")
}
}
func randomBytes(out []byte, rand *rand.Rand) {
for i := 0; i < len(out); i++ {
out[i] = byte(rand.Int31())
}
}
func randomNameList(rand *rand.Rand) []string {
ret := make([]string, rand.Int31()&15)
for i := range ret {
s := make([]byte, 1+(rand.Int31()&15))
for j := range s {
s[j] = 'a' + uint8(rand.Int31()&15)
}
ret[i] = string(s)
}
return ret
}
func randomInt(rand *rand.Rand) *big.Int {
return new(big.Int).SetInt64(int64(int32(rand.Uint32())))
}
func (*kexInitMsg) Generate(rand *rand.Rand, size int) reflect.Value {
ki := &kexInitMsg{}
randomBytes(ki.Cookie[:], rand)
ki.KexAlgos = randomNameList(rand)
ki.ServerHostKeyAlgos = randomNameList(rand)
ki.CiphersClientServer = randomNameList(rand)
ki.CiphersServerClient = randomNameList(rand)
ki.MACsClientServer = randomNameList(rand)
ki.MACsServerClient = randomNameList(rand)
ki.CompressionClientServer = randomNameList(rand)
ki.CompressionServerClient = randomNameList(rand)
ki.LanguagesClientServer = randomNameList(rand)
ki.LanguagesServerClient = randomNameList(rand)
if rand.Int31()&1 == 1 {
ki.FirstKexFollows = true
}
return reflect.ValueOf(ki)
}
func (*kexDHInitMsg) Generate(rand *rand.Rand, size int) reflect.Value {
dhi := &kexDHInitMsg{}
dhi.X = randomInt(rand)
return reflect.ValueOf(dhi)
}
var (
_kexInitMsg = new(kexInitMsg).Generate(rand.New(rand.NewSource(0)), 10).Elem().Interface()
_kexDHInitMsg = new(kexDHInitMsg).Generate(rand.New(rand.NewSource(0)), 10).Elem().Interface()
_kexInit = Marshal(_kexInitMsg)
_kexDHInit = Marshal(_kexDHInitMsg)
)
func BenchmarkMarshalKexInitMsg(b *testing.B) {
for i := 0; i < b.N; i++ {
Marshal(_kexInitMsg)
}
}
func BenchmarkUnmarshalKexInitMsg(b *testing.B) {
m := new(kexInitMsg)
for i := 0; i < b.N; i++ {
Unmarshal(_kexInit, m)
}
}
func BenchmarkMarshalKexDHInitMsg(b *testing.B) {
for i := 0; i < b.N; i++ {
Marshal(_kexDHInitMsg)
}
}
func BenchmarkUnmarshalKexDHInitMsg(b *testing.B) {
m := new(kexDHInitMsg)
for i := 0; i < b.N; i++ {
Unmarshal(_kexDHInit, m)
}
}

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modules/crypto/ssh/mux.go
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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"encoding/binary"
"fmt"
"io"
"log"
"sync"
"sync/atomic"
)
// debugMux, if set, causes messages in the connection protocol to be
// logged.
const debugMux = false
// chanList is a thread safe channel list.
type chanList struct {
// protects concurrent access to chans
sync.Mutex
// chans are indexed by the local id of the channel, which the
// other side should send in the PeersId field.
chans []*channel
// This is a debugging aid: it offsets all IDs by this
// amount. This helps distinguish otherwise identical
// server/client muxes
offset uint32
}
// Assigns a channel ID to the given channel.
func (c *chanList) add(ch *channel) uint32 {
c.Lock()
defer c.Unlock()
for i := range c.chans {
if c.chans[i] == nil {
c.chans[i] = ch
return uint32(i) + c.offset
}
}
c.chans = append(c.chans, ch)
return uint32(len(c.chans)-1) + c.offset
}
// getChan returns the channel for the given ID.
func (c *chanList) getChan(id uint32) *channel {
id -= c.offset
c.Lock()
defer c.Unlock()
if id < uint32(len(c.chans)) {
return c.chans[id]
}
return nil
}
func (c *chanList) remove(id uint32) {
id -= c.offset
c.Lock()
if id < uint32(len(c.chans)) {
c.chans[id] = nil
}
c.Unlock()
}
// dropAll forgets all channels it knows, returning them in a slice.
func (c *chanList) dropAll() []*channel {
c.Lock()
defer c.Unlock()
var r []*channel
for _, ch := range c.chans {
if ch == nil {
continue
}
r = append(r, ch)
}
c.chans = nil
return r
}
// mux represents the state for the SSH connection protocol, which
// multiplexes many channels onto a single packet transport.
type mux struct {
conn packetConn
chanList chanList
incomingChannels chan NewChannel
globalSentMu sync.Mutex
globalResponses chan interface{}
incomingRequests chan *Request
errCond *sync.Cond
err error
}
// When debugging, each new chanList instantiation has a different
// offset.
var globalOff uint32
func (m *mux) Wait() error {
m.errCond.L.Lock()
defer m.errCond.L.Unlock()
for m.err == nil {
m.errCond.Wait()
}
return m.err
}
// newMux returns a mux that runs over the given connection.
func newMux(p packetConn) *mux {
m := &mux{
conn: p,
incomingChannels: make(chan NewChannel, 16),
globalResponses: make(chan interface{}, 1),
incomingRequests: make(chan *Request, 16),
errCond: newCond(),
}
if debugMux {
m.chanList.offset = atomic.AddUint32(&globalOff, 1)
}
go m.loop()
return m
}
func (m *mux) sendMessage(msg interface{}) error {
p := Marshal(msg)
return m.conn.writePacket(p)
}
func (m *mux) SendRequest(name string, wantReply bool, payload []byte) (bool, []byte, error) {
if wantReply {
m.globalSentMu.Lock()
defer m.globalSentMu.Unlock()
}
if err := m.sendMessage(globalRequestMsg{
Type: name,
WantReply: wantReply,
Data: payload,
}); err != nil {
return false, nil, err
}
if !wantReply {
return false, nil, nil
}
msg, ok := <-m.globalResponses
if !ok {
return false, nil, io.EOF
}
switch msg := msg.(type) {
case *globalRequestFailureMsg:
return false, msg.Data, nil
case *globalRequestSuccessMsg:
return true, msg.Data, nil
default:
return false, nil, fmt.Errorf("ssh: unexpected response to request: %#v", msg)
}
}
// ackRequest must be called after processing a global request that
// has WantReply set.
func (m *mux) ackRequest(ok bool, data []byte) error {
if ok {
return m.sendMessage(globalRequestSuccessMsg{Data: data})
}
return m.sendMessage(globalRequestFailureMsg{Data: data})
}
// TODO(hanwen): Disconnect is a transport layer message. We should
// probably send and receive Disconnect somewhere in the transport
// code.
// Disconnect sends a disconnect message.
func (m *mux) Disconnect(reason uint32, message string) error {
return m.sendMessage(disconnectMsg{
Reason: reason,
Message: message,
})
}
func (m *mux) Close() error {
return m.conn.Close()
}
// loop runs the connection machine. It will process packets until an
// error is encountered. To synchronize on loop exit, use mux.Wait.
func (m *mux) loop() {
var err error
for err == nil {
err = m.onePacket()
}
for _, ch := range m.chanList.dropAll() {
ch.close()
}
close(m.incomingChannels)
close(m.incomingRequests)
close(m.globalResponses)
m.conn.Close()
m.errCond.L.Lock()
m.err = err
m.errCond.Broadcast()
m.errCond.L.Unlock()
if debugMux {
log.Println("loop exit", err)
}
}
// onePacket reads and processes one packet.
func (m *mux) onePacket() error {
packet, err := m.conn.readPacket()
if err != nil {
return err
}
if debugMux {
if packet[0] == msgChannelData || packet[0] == msgChannelExtendedData {
log.Printf("decoding(%d): data packet - %d bytes", m.chanList.offset, len(packet))
} else {
p, _ := decode(packet)
log.Printf("decoding(%d): %d %#v - %d bytes", m.chanList.offset, packet[0], p, len(packet))
}
}
switch packet[0] {
case msgNewKeys:
// Ignore notification of key change.
return nil
case msgDisconnect:
return m.handleDisconnect(packet)
case msgChannelOpen:
return m.handleChannelOpen(packet)
case msgGlobalRequest, msgRequestSuccess, msgRequestFailure:
return m.handleGlobalPacket(packet)
}
// assume a channel packet.
if len(packet) < 5 {
return parseError(packet[0])
}
id := binary.BigEndian.Uint32(packet[1:])
ch := m.chanList.getChan(id)
if ch == nil {
return fmt.Errorf("ssh: invalid channel %d", id)
}
return ch.handlePacket(packet)
}
func (m *mux) handleDisconnect(packet []byte) error {
var d disconnectMsg
if err := Unmarshal(packet, &d); err != nil {
return err
}
if debugMux {
log.Printf("caught disconnect: %v", d)
}
return &d
}
func (m *mux) handleGlobalPacket(packet []byte) error {
msg, err := decode(packet)
if err != nil {
return err
}
switch msg := msg.(type) {
case *globalRequestMsg:
m.incomingRequests <- &Request{
Type: msg.Type,
WantReply: msg.WantReply,
Payload: msg.Data,
mux: m,
}
case *globalRequestSuccessMsg, *globalRequestFailureMsg:
m.globalResponses <- msg
default:
panic(fmt.Sprintf("not a global message %#v", msg))
}
return nil
}
// handleChannelOpen schedules a channel to be Accept()ed.
func (m *mux) handleChannelOpen(packet []byte) error {
var msg channelOpenMsg
if err := Unmarshal(packet, &msg); err != nil {
return err
}
if msg.MaxPacketSize < minPacketLength || msg.MaxPacketSize > 1<<31 {
failMsg := channelOpenFailureMsg{
PeersId: msg.PeersId,
Reason: ConnectionFailed,
Message: "invalid request",
Language: "en_US.UTF-8",
}
return m.sendMessage(failMsg)
}
c := m.newChannel(msg.ChanType, channelInbound, msg.TypeSpecificData)
c.remoteId = msg.PeersId
c.maxRemotePayload = msg.MaxPacketSize
c.remoteWin.add(msg.PeersWindow)
m.incomingChannels <- c
return nil
}
func (m *mux) OpenChannel(chanType string, extra []byte) (Channel, <-chan *Request, error) {
ch, err := m.openChannel(chanType, extra)
if err != nil {
return nil, nil, err
}
return ch, ch.incomingRequests, nil
}
func (m *mux) openChannel(chanType string, extra []byte) (*channel, error) {
ch := m.newChannel(chanType, channelOutbound, extra)
ch.maxIncomingPayload = channelMaxPacket
open := channelOpenMsg{
ChanType: chanType,
PeersWindow: ch.myWindow,
MaxPacketSize: ch.maxIncomingPayload,
TypeSpecificData: extra,
PeersId: ch.localId,
}
if err := m.sendMessage(open); err != nil {
return nil, err
}
switch msg := (<-ch.msg).(type) {
case *channelOpenConfirmMsg:
return ch, nil
case *channelOpenFailureMsg:
return nil, &OpenChannelError{msg.Reason, msg.Message}
default:
return nil, fmt.Errorf("ssh: unexpected packet in response to channel open: %T", msg)
}
}

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modules/crypto/ssh/mux_test.go
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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"io"
"io/ioutil"
"sync"
"testing"
)
func muxPair() (*mux, *mux) {
a, b := memPipe()
s := newMux(a)
c := newMux(b)
return s, c
}
// Returns both ends of a channel, and the mux for the the 2nd
// channel.
func channelPair(t *testing.T) (*channel, *channel, *mux) {
c, s := muxPair()
res := make(chan *channel, 1)
go func() {
newCh, ok := <-s.incomingChannels
if !ok {
t.Fatalf("No incoming channel")
}
if newCh.ChannelType() != "chan" {
t.Fatalf("got type %q want chan", newCh.ChannelType())
}
ch, _, err := newCh.Accept()
if err != nil {
t.Fatalf("Accept %v", err)
}
res <- ch.(*channel)
}()
ch, err := c.openChannel("chan", nil)
if err != nil {
t.Fatalf("OpenChannel: %v", err)
}
return <-res, ch, c
}
// Test that stderr and stdout can be addressed from different
// goroutines. This is intended for use with the race detector.
func TestMuxChannelExtendedThreadSafety(t *testing.T) {
writer, reader, mux := channelPair(t)
defer writer.Close()
defer reader.Close()
defer mux.Close()
var wr, rd sync.WaitGroup
magic := "hello world"
wr.Add(2)
go func() {
io.WriteString(writer, magic)
wr.Done()
}()
go func() {
io.WriteString(writer.Stderr(), magic)
wr.Done()
}()
rd.Add(2)
go func() {
c, err := ioutil.ReadAll(reader)
if string(c) != magic {
t.Fatalf("stdout read got %q, want %q (error %s)", c, magic, err)
}
rd.Done()
}()
go func() {
c, err := ioutil.ReadAll(reader.Stderr())
if string(c) != magic {
t.Fatalf("stderr read got %q, want %q (error %s)", c, magic, err)
}
rd.Done()
}()
wr.Wait()
writer.CloseWrite()
rd.Wait()
}
func TestMuxReadWrite(t *testing.T) {
s, c, mux := channelPair(t)
defer s.Close()
defer c.Close()
defer mux.Close()
magic := "hello world"
magicExt := "hello stderr"
go func() {
_, err := s.Write([]byte(magic))
if err != nil {
t.Fatalf("Write: %v", err)
}
_, err = s.Extended(1).Write([]byte(magicExt))
if err != nil {
t.Fatalf("Write: %v", err)
}
err = s.Close()
if err != nil {
t.Fatalf("Close: %v", err)
}
}()
var buf [1024]byte
n, err := c.Read(buf[:])
if err != nil {
t.Fatalf("server Read: %v", err)
}
got := string(buf[:n])
if got != magic {
t.Fatalf("server: got %q want %q", got, magic)
}
n, err = c.Extended(1).Read(buf[:])
if err != nil {
t.Fatalf("server Read: %v", err)
}
got = string(buf[:n])
if got != magicExt {
t.Fatalf("server: got %q want %q", got, magic)
}
}
func TestMuxChannelOverflow(t *testing.T) {
reader, writer, mux := channelPair(t)
defer reader.Close()
defer writer.Close()
defer mux.Close()
wDone := make(chan int, 1)
go func() {
if _, err := writer.Write(make([]byte, channelWindowSize)); err != nil {
t.Errorf("could not fill window: %v", err)
}
writer.Write(make([]byte, 1))
wDone <- 1
}()
writer.remoteWin.waitWriterBlocked()
// Send 1 byte.
packet := make([]byte, 1+4+4+1)
packet[0] = msgChannelData
marshalUint32(packet[1:], writer.remoteId)
marshalUint32(packet[5:], uint32(1))
packet[9] = 42
if err := writer.mux.conn.writePacket(packet); err != nil {
t.Errorf("could not send packet")
}
if _, err := reader.SendRequest("hello", true, nil); err == nil {
t.Errorf("SendRequest succeeded.")
}
<-wDone
}
func TestMuxChannelCloseWriteUnblock(t *testing.T) {
reader, writer, mux := channelPair(t)
defer reader.Close()
defer writer.Close()
defer mux.Close()
wDone := make(chan int, 1)
go func() {
if _, err := writer.Write(make([]byte, channelWindowSize)); err != nil {
t.Errorf("could not fill window: %v", err)
}
if _, err := writer.Write(make([]byte, 1)); err != io.EOF {
t.Errorf("got %v, want EOF for unblock write", err)
}
wDone <- 1
}()
writer.remoteWin.waitWriterBlocked()
reader.Close()
<-wDone
}
func TestMuxConnectionCloseWriteUnblock(t *testing.T) {
reader, writer, mux := channelPair(t)
defer reader.Close()
defer writer.Close()
defer mux.Close()
wDone := make(chan int, 1)
go func() {
if _, err := writer.Write(make([]byte, channelWindowSize)); err != nil {
t.Errorf("could not fill window: %v", err)
}
if _, err := writer.Write(make([]byte, 1)); err != io.EOF {
t.Errorf("got %v, want EOF for unblock write", err)
}
wDone <- 1
}()
writer.remoteWin.waitWriterBlocked()
mux.Close()
<-wDone
}
func TestMuxReject(t *testing.T) {
client, server := muxPair()
defer server.Close()
defer client.Close()
go func() {
ch, ok := <-server.incomingChannels
if !ok {
t.Fatalf("Accept")
}
if ch.ChannelType() != "ch" || string(ch.ExtraData()) != "extra" {
t.Fatalf("unexpected channel: %q, %q", ch.ChannelType(), ch.ExtraData())
}
ch.Reject(RejectionReason(42), "message")
}()
ch, err := client.openChannel("ch", []byte("extra"))
if ch != nil {
t.Fatal("openChannel not rejected")
}
ocf, ok := err.(*OpenChannelError)
if !ok {
t.Errorf("got %#v want *OpenChannelError", err)
} else if ocf.Reason != 42 || ocf.Message != "message" {
t.Errorf("got %#v, want {Reason: 42, Message: %q}", ocf, "message")
}
want := "ssh: rejected: unknown reason 42 (message)"
if err.Error() != want {
t.Errorf("got %q, want %q", err.Error(), want)
}
}
func TestMuxChannelRequest(t *testing.T) {
client, server, mux := channelPair(t)
defer server.Close()
defer client.Close()
defer mux.Close()
var received int
var wg sync.WaitGroup
wg.Add(1)
go func() {
for r := range server.incomingRequests {
received++
r.Reply(r.Type == "yes", nil)
}
wg.Done()
}()
_, err := client.SendRequest("yes", false, nil)
if err != nil {
t.Fatalf("SendRequest: %v", err)
}
ok, err := client.SendRequest("yes", true, nil)
if err != nil {
t.Fatalf("SendRequest: %v", err)
}
if !ok {
t.Errorf("SendRequest(yes): %v", ok)
}
ok, err = client.SendRequest("no", true, nil)
if err != nil {
t.Fatalf("SendRequest: %v", err)
}
if ok {
t.Errorf("SendRequest(no): %v", ok)
}
client.Close()
wg.Wait()
if received != 3 {
t.Errorf("got %d requests, want %d", received, 3)
}
}
func TestMuxGlobalRequest(t *testing.T) {
clientMux, serverMux := muxPair()
defer serverMux.Close()
defer clientMux.Close()
var seen bool
go func() {
for r := range serverMux.incomingRequests {
seen = seen || r.Type == "peek"
if r.WantReply {
err := r.Reply(r.Type == "yes",
append([]byte(r.Type), r.Payload...))
if err != nil {
t.Errorf("AckRequest: %v", err)
}
}
}
}()
_, _, err := clientMux.SendRequest("peek", false, nil)
if err != nil {
t.Errorf("SendRequest: %v", err)
}
ok, data, err := clientMux.SendRequest("yes", true, []byte("a"))
if !ok || string(data) != "yesa" || err != nil {
t.Errorf("SendRequest(\"yes\", true, \"a\"): %v %v %v",
ok, data, err)
}
if ok, data, err := clientMux.SendRequest("yes", true, []byte("a")); !ok || string(data) != "yesa" || err != nil {
t.Errorf("SendRequest(\"yes\", true, \"a\"): %v %v %v",
ok, data, err)
}
if ok, data, err := clientMux.SendRequest("no", true, []byte("a")); ok || string(data) != "noa" || err != nil {
t.Errorf("SendRequest(\"no\", true, \"a\"): %v %v %v",
ok, data, err)
}
clientMux.Disconnect(0, "")
if !seen {
t.Errorf("never saw 'peek' request")
}
}
func TestMuxGlobalRequestUnblock(t *testing.T) {
clientMux, serverMux := muxPair()
defer serverMux.Close()
defer clientMux.Close()
result := make(chan error, 1)
go func() {
_, _, err := clientMux.SendRequest("hello", true, nil)
result <- err
}()
<-serverMux.incomingRequests
serverMux.conn.Close()
err := <-result
if err != io.EOF {
t.Errorf("want EOF, got %v", io.EOF)
}
}
func TestMuxChannelRequestUnblock(t *testing.T) {
a, b, connB := channelPair(t)
defer a.Close()
defer b.Close()
defer connB.Close()
result := make(chan error, 1)
go func() {
_, err := a.SendRequest("hello", true, nil)
result <- err
}()
<-b.incomingRequests
connB.conn.Close()
err := <-result
if err != io.EOF {
t.Errorf("want EOF, got %v", err)
}
}
func TestMuxDisconnect(t *testing.T) {
a, b := muxPair()
defer a.Close()
defer b.Close()
go func() {
for r := range b.incomingRequests {
r.Reply(true, nil)
}
}()
a.Disconnect(42, "whatever")
ok, _, err := a.SendRequest("hello", true, nil)
if ok || err == nil {
t.Errorf("got reply after disconnecting")
}
err = b.Wait()
if d, ok := err.(*disconnectMsg); !ok || d.Reason != 42 {
t.Errorf("got %#v, want disconnectMsg{Reason:42}", err)
}
}
func TestMuxCloseChannel(t *testing.T) {
r, w, mux := channelPair(t)
defer mux.Close()
defer r.Close()
defer w.Close()
result := make(chan error, 1)
go func() {
var b [1024]byte
_, err := r.Read(b[:])
result <- err
}()
if err := w.Close(); err != nil {
t.Errorf("w.Close: %v", err)
}
if _, err := w.Write([]byte("hello")); err != io.EOF {
t.Errorf("got err %v, want io.EOF after Close", err)
}
if err := <-result; err != io.EOF {
t.Errorf("got %v (%T), want io.EOF", err, err)
}
}
func TestMuxCloseWriteChannel(t *testing.T) {
r, w, mux := channelPair(t)
defer mux.Close()
result := make(chan error, 1)
go func() {
var b [1024]byte
_, err := r.Read(b[:])
result <- err
}()
if err := w.CloseWrite(); err != nil {
t.Errorf("w.CloseWrite: %v", err)
}
if _, err := w.Write([]byte("hello")); err != io.EOF {
t.Errorf("got err %v, want io.EOF after CloseWrite", err)
}
if err := <-result; err != io.EOF {
t.Errorf("got %v (%T), want io.EOF", err, err)
}
}
func TestMuxInvalidRecord(t *testing.T) {
a, b := muxPair()
defer a.Close()
defer b.Close()
packet := make([]byte, 1+4+4+1)
packet[0] = msgChannelData
marshalUint32(packet[1:], 29348723 /* invalid channel id */)
marshalUint32(packet[5:], 1)
packet[9] = 42
a.conn.writePacket(packet)
go a.SendRequest("hello", false, nil)
// 'a' wrote an invalid packet, so 'b' has exited.
req, ok := <-b.incomingRequests
if ok {
t.Errorf("got request %#v after receiving invalid packet", req)
}
}
func TestZeroWindowAdjust(t *testing.T) {
a, b, mux := channelPair(t)
defer a.Close()
defer b.Close()
defer mux.Close()
go func() {
io.WriteString(a, "hello")
// bogus adjust.
a.sendMessage(windowAdjustMsg{})
io.WriteString(a, "world")
a.Close()
}()
want := "helloworld"
c, _ := ioutil.ReadAll(b)
if string(c) != want {
t.Errorf("got %q want %q", c, want)
}
}
func TestMuxMaxPacketSize(t *testing.T) {
a, b, mux := channelPair(t)
defer a.Close()
defer b.Close()
defer mux.Close()
large := make([]byte, a.maxRemotePayload+1)
packet := make([]byte, 1+4+4+1+len(large))
packet[0] = msgChannelData
marshalUint32(packet[1:], a.remoteId)
marshalUint32(packet[5:], uint32(len(large)))
packet[9] = 42
if err := a.mux.conn.writePacket(packet); err != nil {
t.Errorf("could not send packet")
}
go a.SendRequest("hello", false, nil)
_, ok := <-b.incomingRequests
if ok {
t.Errorf("connection still alive after receiving large packet.")
}
}
// Don't ship code with debug=true.
func TestDebug(t *testing.T) {
if debugMux {
t.Error("mux debug switched on")
}
if debugHandshake {
t.Error("handshake debug switched on")
}
}

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modules/crypto/ssh/server.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"bytes"
"errors"
"fmt"
"io"
"net"
)
// The Permissions type holds fine-grained permissions that are
// specific to a user or a specific authentication method for a
// user. Permissions, except for "source-address", must be enforced in
// the server application layer, after successful authentication. The
// Permissions are passed on in ServerConn so a server implementation
// can honor them.
type Permissions struct {
// Critical options restrict default permissions. Common
// restrictions are "source-address" and "force-command". If
// the server cannot enforce the restriction, or does not
// recognize it, the user should not authenticate.
CriticalOptions map[string]string
// Extensions are extra functionality that the server may
// offer on authenticated connections. Common extensions are
// "permit-agent-forwarding", "permit-X11-forwarding". Lack of
// support for an extension does not preclude authenticating a
// user.
Extensions map[string]string
}
// ServerConfig holds server specific configuration data.
type ServerConfig struct {
// Config contains configuration shared between client and server.
Config
hostKeys []Signer
// NoClientAuth is true if clients are allowed to connect without
// authenticating.
NoClientAuth bool
// PasswordCallback, if non-nil, is called when a user
// attempts to authenticate using a password.
PasswordCallback func(conn ConnMetadata, password []byte) (*Permissions, error)
// PublicKeyCallback, if non-nil, is called when a client attempts public
// key authentication. It must return true if the given public key is
// valid for the given user. For example, see CertChecker.Authenticate.
PublicKeyCallback func(conn ConnMetadata, key PublicKey) (*Permissions, error)
// KeyboardInteractiveCallback, if non-nil, is called when
// keyboard-interactive authentication is selected (RFC
// 4256). The client object's Challenge function should be
// used to query the user. The callback may offer multiple
// Challenge rounds. To avoid information leaks, the client
// should be presented a challenge even if the user is
// unknown.
KeyboardInteractiveCallback func(conn ConnMetadata, client KeyboardInteractiveChallenge) (*Permissions, error)
// AuthLogCallback, if non-nil, is called to log all authentication
// attempts.
AuthLogCallback func(conn ConnMetadata, method string, err error)
// ServerVersion is the version identification string to
// announce in the public handshake.
// If empty, a reasonable default is used.
ServerVersion string
}
// AddHostKey adds a private key as a host key. If an existing host
// key exists with the same algorithm, it is overwritten. Each server
// config must have at least one host key.
func (s *ServerConfig) AddHostKey(key Signer) {
for i, k := range s.hostKeys {
if k.PublicKey().Type() == key.PublicKey().Type() {
s.hostKeys[i] = key
return
}
}
s.hostKeys = append(s.hostKeys, key)
}
// cachedPubKey contains the results of querying whether a public key is
// acceptable for a user.
type cachedPubKey struct {
user string
pubKeyData []byte
result error
perms *Permissions
}
const maxCachedPubKeys = 16
// pubKeyCache caches tests for public keys. Since SSH clients
// will query whether a public key is acceptable before attempting to
// authenticate with it, we end up with duplicate queries for public
// key validity. The cache only applies to a single ServerConn.
type pubKeyCache struct {
keys []cachedPubKey
}
// get returns the result for a given user/algo/key tuple.
func (c *pubKeyCache) get(user string, pubKeyData []byte) (cachedPubKey, bool) {
for _, k := range c.keys {
if k.user == user && bytes.Equal(k.pubKeyData, pubKeyData) {
return k, true
}
}
return cachedPubKey{}, false
}
// add adds the given tuple to the cache.
func (c *pubKeyCache) add(candidate cachedPubKey) {
if len(c.keys) < maxCachedPubKeys {
c.keys = append(c.keys, candidate)
}
}
// ServerConn is an authenticated SSH connection, as seen from the
// server
type ServerConn struct {
Conn
// If the succeeding authentication callback returned a
// non-nil Permissions pointer, it is stored here.
Permissions *Permissions
}
// NewServerConn starts a new SSH server with c as the underlying
// transport. It starts with a handshake and, if the handshake is
// unsuccessful, it closes the connection and returns an error. The
// Request and NewChannel channels must be serviced, or the connection
// will hang.
func NewServerConn(c net.Conn, config *ServerConfig) (*ServerConn, <-chan NewChannel, <-chan *Request, error) {
fullConf := *config
fullConf.SetDefaults()
s := &connection{
sshConn: sshConn{conn: c},
}
perms, err := s.serverHandshake(&fullConf)
if err != nil {
c.Close()
return nil, nil, nil, err
}
return &ServerConn{s, perms}, s.mux.incomingChannels, s.mux.incomingRequests, nil
}
// signAndMarshal signs the data with the appropriate algorithm,
// and serializes the result in SSH wire format.
func signAndMarshal(k Signer, rand io.Reader, data []byte) ([]byte, error) {
sig, err := k.Sign(rand, data)
if err != nil {
return nil, err
}
return Marshal(sig), nil
}
// handshake performs key exchange and user authentication.
func (s *connection) serverHandshake(config *ServerConfig) (*Permissions, error) {
if len(config.hostKeys) == 0 {
return nil, errors.New("ssh: server has no host keys")
}
if !config.NoClientAuth && config.PasswordCallback == nil && config.PublicKeyCallback == nil && config.KeyboardInteractiveCallback == nil {
return nil, errors.New("ssh: no authentication methods configured but NoClientAuth is also false")
}
if config.ServerVersion != "" {
s.serverVersion = []byte(config.ServerVersion)
} else {
s.serverVersion = []byte(packageVersion)
}
var err error
s.clientVersion, err = exchangeVersions(s.sshConn.conn, s.serverVersion)
if err != nil {
return nil, err
}
tr := newTransport(s.sshConn.conn, config.Rand, false /* not client */)
s.transport = newServerTransport(tr, s.clientVersion, s.serverVersion, config)
if err := s.transport.requestKeyChange(); err != nil {
return nil, err
}
if packet, err := s.transport.readPacket(); err != nil {
return nil, err
} else if packet[0] != msgNewKeys {
return nil, unexpectedMessageError(msgNewKeys, packet[0])
}
// We just did the key change, so the session ID is established.
s.sessionID = s.transport.getSessionID()
var packet []byte
if packet, err = s.transport.readPacket(); err != nil {
return nil, err
}
var serviceRequest serviceRequestMsg
if err = Unmarshal(packet, &serviceRequest); err != nil {
return nil, err
}
if serviceRequest.Service != serviceUserAuth {
return nil, errors.New("ssh: requested service '" + serviceRequest.Service + "' before authenticating")
}
serviceAccept := serviceAcceptMsg{
Service: serviceUserAuth,
}
if err := s.transport.writePacket(Marshal(&serviceAccept)); err != nil {
return nil, err
}
perms, err := s.serverAuthenticate(config)
if err != nil {
return nil, err
}
s.mux = newMux(s.transport)
return perms, err
}
func isAcceptableAlgo(algo string) bool {
switch algo {
case KeyAlgoRSA, KeyAlgoDSA, KeyAlgoECDSA256, KeyAlgoECDSA384, KeyAlgoECDSA521,
CertAlgoRSAv01, CertAlgoDSAv01, CertAlgoECDSA256v01, CertAlgoECDSA384v01, CertAlgoECDSA521v01:
return true
}
return false
}
func checkSourceAddress(addr net.Addr, sourceAddr string) error {
if addr == nil {
return errors.New("ssh: no address known for client, but source-address match required")
}
tcpAddr, ok := addr.(*net.TCPAddr)
if !ok {
return fmt.Errorf("ssh: remote address %v is not an TCP address when checking source-address match", addr)
}
if allowedIP := net.ParseIP(sourceAddr); allowedIP != nil {
if bytes.Equal(allowedIP, tcpAddr.IP) {
return nil
}
} else {
_, ipNet, err := net.ParseCIDR(sourceAddr)
if err != nil {
return fmt.Errorf("ssh: error parsing source-address restriction %q: %v", sourceAddr, err)
}
if ipNet.Contains(tcpAddr.IP) {
return nil
}
}
return fmt.Errorf("ssh: remote address %v is not allowed because of source-address restriction", addr)
}
func (s *connection) serverAuthenticate(config *ServerConfig) (*Permissions, error) {
var err error
var cache pubKeyCache
var perms *Permissions
userAuthLoop:
for {
var userAuthReq userAuthRequestMsg
if packet, err := s.transport.readPacket(); err != nil {
return nil, err
} else if err = Unmarshal(packet, &userAuthReq); err != nil {
return nil, err
}
if userAuthReq.Service != serviceSSH {
return nil, errors.New("ssh: client attempted to negotiate for unknown service: " + userAuthReq.Service)
}
s.user = userAuthReq.User
perms = nil
authErr := errors.New("no auth passed yet")
switch userAuthReq.Method {
case "none":
if config.NoClientAuth {
s.user = ""
authErr = nil
}
case "password":
if config.PasswordCallback == nil {
authErr = errors.New("ssh: password auth not configured")
break
}
payload := userAuthReq.Payload
if len(payload) < 1 || payload[0] != 0 {
return nil, parseError(msgUserAuthRequest)
}
payload = payload[1:]
password, payload, ok := parseString(payload)
if !ok || len(payload) > 0 {
return nil, parseError(msgUserAuthRequest)
}
perms, authErr = config.PasswordCallback(s, password)
case "keyboard-interactive":
if config.KeyboardInteractiveCallback == nil {
authErr = errors.New("ssh: keyboard-interactive auth not configubred")
break
}
prompter := &sshClientKeyboardInteractive{s}
perms, authErr = config.KeyboardInteractiveCallback(s, prompter.Challenge)
case "publickey":
if config.PublicKeyCallback == nil {
authErr = errors.New("ssh: publickey auth not configured")
break
}
payload := userAuthReq.Payload
if len(payload) < 1 {
return nil, parseError(msgUserAuthRequest)
}
isQuery := payload[0] == 0
payload = payload[1:]
algoBytes, payload, ok := parseString(payload)
if !ok {
return nil, parseError(msgUserAuthRequest)
}
algo := string(algoBytes)
if !isAcceptableAlgo(algo) {
authErr = fmt.Errorf("ssh: algorithm %q not accepted", algo)
break
}
pubKeyData, payload, ok := parseString(payload)
if !ok {
return nil, parseError(msgUserAuthRequest)
}
pubKey, err := ParsePublicKey(pubKeyData)
if err != nil {
return nil, err
}
candidate, ok := cache.get(s.user, pubKeyData)
if !ok {
candidate.user = s.user
candidate.pubKeyData = pubKeyData
candidate.perms, candidate.result = config.PublicKeyCallback(s, pubKey)
if candidate.result == nil && candidate.perms != nil && candidate.perms.CriticalOptions != nil && candidate.perms.CriticalOptions[sourceAddressCriticalOption] != "" {
candidate.result = checkSourceAddress(
s.RemoteAddr(),
candidate.perms.CriticalOptions[sourceAddressCriticalOption])
}
cache.add(candidate)
}
if isQuery {
// The client can query if the given public key
// would be okay.
if len(payload) > 0 {
return nil, parseError(msgUserAuthRequest)
}
if candidate.result == nil {
okMsg := userAuthPubKeyOkMsg{
Algo: algo,
PubKey: pubKeyData,
}
if err = s.transport.writePacket(Marshal(&okMsg)); err != nil {
return nil, err
}
continue userAuthLoop
}
authErr = candidate.result
} else {
sig, payload, ok := parseSignature(payload)
if !ok || len(payload) > 0 {
return nil, parseError(msgUserAuthRequest)
}
// Ensure the public key algo and signature algo
// are supported. Compare the private key
// algorithm name that corresponds to algo with
// sig.Format. This is usually the same, but
// for certs, the names differ.
if !isAcceptableAlgo(sig.Format) {
break
}
signedData := buildDataSignedForAuth(s.transport.getSessionID(), userAuthReq, algoBytes, pubKeyData)
if err := pubKey.Verify(signedData, sig); err != nil {
return nil, err
}
authErr = candidate.result
perms = candidate.perms
}
default:
authErr = fmt.Errorf("ssh: unknown method %q", userAuthReq.Method)
}
if config.AuthLogCallback != nil {
config.AuthLogCallback(s, userAuthReq.Method, authErr)
}
if authErr == nil {
break userAuthLoop
}
var failureMsg userAuthFailureMsg
if config.PasswordCallback != nil {
failureMsg.Methods = append(failureMsg.Methods, "password")
}
if config.PublicKeyCallback != nil {
failureMsg.Methods = append(failureMsg.Methods, "publickey")
}
if config.KeyboardInteractiveCallback != nil {
failureMsg.Methods = append(failureMsg.Methods, "keyboard-interactive")
}
if len(failureMsg.Methods) == 0 {
return nil, errors.New("ssh: no authentication methods configured but NoClientAuth is also false")
}
if err = s.transport.writePacket(Marshal(&failureMsg)); err != nil {
return nil, err
}
}
if err = s.transport.writePacket([]byte{msgUserAuthSuccess}); err != nil {
return nil, err
}
return perms, nil
}
// sshClientKeyboardInteractive implements a ClientKeyboardInteractive by
// asking the client on the other side of a ServerConn.
type sshClientKeyboardInteractive struct {
*connection
}
func (c *sshClientKeyboardInteractive) Challenge(user, instruction string, questions []string, echos []bool) (answers []string, err error) {
if len(questions) != len(echos) {
return nil, errors.New("ssh: echos and questions must have equal length")
}
var prompts []byte
for i := range questions {
prompts = appendString(prompts, questions[i])
prompts = appendBool(prompts, echos[i])
}
if err := c.transport.writePacket(Marshal(&userAuthInfoRequestMsg{
Instruction: instruction,
NumPrompts: uint32(len(questions)),
Prompts: prompts,
})); err != nil {
return nil, err
}
packet, err := c.transport.readPacket()
if err != nil {
return nil, err
}
if packet[0] != msgUserAuthInfoResponse {
return nil, unexpectedMessageError(msgUserAuthInfoResponse, packet[0])
}
packet = packet[1:]
n, packet, ok := parseUint32(packet)
if !ok || int(n) != len(questions) {
return nil, parseError(msgUserAuthInfoResponse)
}
for i := uint32(0); i < n; i++ {
ans, rest, ok := parseString(packet)
if !ok {
return nil, parseError(msgUserAuthInfoResponse)
}
answers = append(answers, string(ans))
packet = rest
}
if len(packet) != 0 {
return nil, errors.New("ssh: junk at end of message")
}
return answers, nil
}

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modules/crypto/ssh/session.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
// Session implements an interactive session described in
// "RFC 4254, section 6".
import (
"bytes"
"errors"
"fmt"
"io"
"io/ioutil"
"sync"
)
type Signal string
// POSIX signals as listed in RFC 4254 Section 6.10.
const (
SIGABRT Signal = "ABRT"
SIGALRM Signal = "ALRM"
SIGFPE Signal = "FPE"
SIGHUP Signal = "HUP"
SIGILL Signal = "ILL"
SIGINT Signal = "INT"
SIGKILL Signal = "KILL"
SIGPIPE Signal = "PIPE"
SIGQUIT Signal = "QUIT"
SIGSEGV Signal = "SEGV"
SIGTERM Signal = "TERM"
SIGUSR1 Signal = "USR1"
SIGUSR2 Signal = "USR2"
)
var signals = map[Signal]int{
SIGABRT: 6,
SIGALRM: 14,
SIGFPE: 8,
SIGHUP: 1,
SIGILL: 4,
SIGINT: 2,
SIGKILL: 9,
SIGPIPE: 13,
SIGQUIT: 3,
SIGSEGV: 11,
SIGTERM: 15,
}
type TerminalModes map[uint8]uint32
// POSIX terminal mode flags as listed in RFC 4254 Section 8.
const (
tty_OP_END = 0
VINTR = 1
VQUIT = 2
VERASE = 3
VKILL = 4
VEOF = 5
VEOL = 6
VEOL2 = 7
VSTART = 8
VSTOP = 9
VSUSP = 10
VDSUSP = 11
VREPRINT = 12
VWERASE = 13
VLNEXT = 14
VFLUSH = 15
VSWTCH = 16
VSTATUS = 17
VDISCARD = 18
IGNPAR = 30
PARMRK = 31
INPCK = 32
ISTRIP = 33
INLCR = 34
IGNCR = 35
ICRNL = 36
IUCLC = 37
IXON = 38
IXANY = 39
IXOFF = 40
IMAXBEL = 41
ISIG = 50
ICANON = 51
XCASE = 52
ECHO = 53
ECHOE = 54
ECHOK = 55
ECHONL = 56
NOFLSH = 57
TOSTOP = 58
IEXTEN = 59
ECHOCTL = 60
ECHOKE = 61
PENDIN = 62
OPOST = 70
OLCUC = 71
ONLCR = 72
OCRNL = 73
ONOCR = 74
ONLRET = 75
CS7 = 90
CS8 = 91
PARENB = 92
PARODD = 93
TTY_OP_ISPEED = 128
TTY_OP_OSPEED = 129
)
// A Session represents a connection to a remote command or shell.
type Session struct {
// Stdin specifies the remote process's standard input.
// If Stdin is nil, the remote process reads from an empty
// bytes.Buffer.
Stdin io.Reader
// Stdout and Stderr specify the remote process's standard
// output and error.
//
// If either is nil, Run connects the corresponding file
// descriptor to an instance of ioutil.Discard. There is a
// fixed amount of buffering that is shared for the two streams.
// If either blocks it may eventually cause the remote
// command to block.
Stdout io.Writer
Stderr io.Writer
ch Channel // the channel backing this session
started bool // true once Start, Run or Shell is invoked.
copyFuncs []func() error
errors chan error // one send per copyFunc
// true if pipe method is active
stdinpipe, stdoutpipe, stderrpipe bool
// stdinPipeWriter is non-nil if StdinPipe has not been called
// and Stdin was specified by the user; it is the write end of
// a pipe connecting Session.Stdin to the stdin channel.
stdinPipeWriter io.WriteCloser
exitStatus chan error
}
// SendRequest sends an out-of-band channel request on the SSH channel
// underlying the session.
func (s *Session) SendRequest(name string, wantReply bool, payload []byte) (bool, error) {
return s.ch.SendRequest(name, wantReply, payload)
}
func (s *Session) Close() error {
return s.ch.Close()
}
// RFC 4254 Section 6.4.
type setenvRequest struct {
Name string
Value string
}
// Setenv sets an environment variable that will be applied to any
// command executed by Shell or Run.
func (s *Session) Setenv(name, value string) error {
msg := setenvRequest{
Name: name,
Value: value,
}
ok, err := s.ch.SendRequest("env", true, Marshal(&msg))
if err == nil && !ok {
err = errors.New("ssh: setenv failed")
}
return err
}
// RFC 4254 Section 6.2.
type ptyRequestMsg struct {
Term string
Columns uint32
Rows uint32
Width uint32
Height uint32
Modelist string
}
// RequestPty requests the association of a pty with the session on the remote host.
func (s *Session) RequestPty(term string, h, w int, termmodes TerminalModes) error {
var tm []byte
for k, v := range termmodes {
kv := struct {
Key byte
Val uint32
}{k, v}
tm = append(tm, Marshal(&kv)...)
}
tm = append(tm, tty_OP_END)
req := ptyRequestMsg{
Term: term,
Columns: uint32(w),
Rows: uint32(h),
Width: uint32(w * 8),
Height: uint32(h * 8),
Modelist: string(tm),
}
ok, err := s.ch.SendRequest("pty-req", true, Marshal(&req))
if err == nil && !ok {
err = errors.New("ssh: pty-req failed")
}
return err
}
// RFC 4254 Section 6.5.
type subsystemRequestMsg struct {
Subsystem string
}
// RequestSubsystem requests the association of a subsystem with the session on the remote host.
// A subsystem is a predefined command that runs in the background when the ssh session is initiated
func (s *Session) RequestSubsystem(subsystem string) error {
msg := subsystemRequestMsg{
Subsystem: subsystem,
}
ok, err := s.ch.SendRequest("subsystem", true, Marshal(&msg))
if err == nil && !ok {
err = errors.New("ssh: subsystem request failed")
}
return err
}
// RFC 4254 Section 6.9.
type signalMsg struct {
Signal string
}
// Signal sends the given signal to the remote process.
// sig is one of the SIG* constants.
func (s *Session) Signal(sig Signal) error {
msg := signalMsg{
Signal: string(sig),
}
_, err := s.ch.SendRequest("signal", false, Marshal(&msg))
return err
}
// RFC 4254 Section 6.5.
type execMsg struct {
Command string
}
// Start runs cmd on the remote host. Typically, the remote
// server passes cmd to the shell for interpretation.
// A Session only accepts one call to Run, Start or Shell.
func (s *Session) Start(cmd string) error {
if s.started {
return errors.New("ssh: session already started")
}
req := execMsg{
Command: cmd,
}
ok, err := s.ch.SendRequest("exec", true, Marshal(&req))
if err == nil && !ok {
err = fmt.Errorf("ssh: command %v failed", cmd)
}
if err != nil {
return err
}
return s.start()
}
// Run runs cmd on the remote host. Typically, the remote
// server passes cmd to the shell for interpretation.
// A Session only accepts one call to Run, Start, Shell, Output,
// or CombinedOutput.
//
// The returned error is nil if the command runs, has no problems
// copying stdin, stdout, and stderr, and exits with a zero exit
// status.
//
// If the command fails to run or doesn't complete successfully, the
// error is of type *ExitError. Other error types may be
// returned for I/O problems.
func (s *Session) Run(cmd string) error {
err := s.Start(cmd)
if err != nil {
return err
}
return s.Wait()
}
// Output runs cmd on the remote host and returns its standard output.
func (s *Session) Output(cmd string) ([]byte, error) {
if s.Stdout != nil {
return nil, errors.New("ssh: Stdout already set")
}
var b bytes.Buffer
s.Stdout = &b
err := s.Run(cmd)
return b.Bytes(), err
}
type singleWriter struct {
b bytes.Buffer
mu sync.Mutex
}
func (w *singleWriter) Write(p []byte) (int, error) {
w.mu.Lock()
defer w.mu.Unlock()
return w.b.Write(p)
}
// CombinedOutput runs cmd on the remote host and returns its combined
// standard output and standard error.
func (s *Session) CombinedOutput(cmd string) ([]byte, error) {
if s.Stdout != nil {
return nil, errors.New("ssh: Stdout already set")
}
if s.Stderr != nil {
return nil, errors.New("ssh: Stderr already set")
}
var b singleWriter
s.Stdout = &b
s.Stderr = &b
err := s.Run(cmd)
return b.b.Bytes(), err
}
// Shell starts a login shell on the remote host. A Session only
// accepts one call to Run, Start, Shell, Output, or CombinedOutput.
func (s *Session) Shell() error {
if s.started {
return errors.New("ssh: session already started")
}
ok, err := s.ch.SendRequest("shell", true, nil)
if err == nil && !ok {
return fmt.Errorf("ssh: cound not start shell")
}
if err != nil {
return err
}
return s.start()
}
func (s *Session) start() error {
s.started = true
type F func(*Session)
for _, setupFd := range []F{(*Session).stdin, (*Session).stdout, (*Session).stderr} {
setupFd(s)
}
s.errors = make(chan error, len(s.copyFuncs))
for _, fn := range s.copyFuncs {
go func(fn func() error) {
s.errors <- fn()
}(fn)
}
return nil
}
// Wait waits for the remote command to exit.
//
// The returned error is nil if the command runs, has no problems
// copying stdin, stdout, and stderr, and exits with a zero exit
// status.
//
// If the command fails to run or doesn't complete successfully, the
// error is of type *ExitError. Other error types may be
// returned for I/O problems.
func (s *Session) Wait() error {
if !s.started {
return errors.New("ssh: session not started")
}
waitErr := <-s.exitStatus
if s.stdinPipeWriter != nil {
s.stdinPipeWriter.Close()
}
var copyError error
for _ = range s.copyFuncs {
if err := <-s.errors; err != nil && copyError == nil {
copyError = err
}
}
if waitErr != nil {
return waitErr
}
return copyError
}
func (s *Session) wait(reqs <-chan *Request) error {
wm := Waitmsg{status: -1}
// Wait for msg channel to be closed before returning.
for msg := range reqs {
switch msg.Type {
case "exit-status":
d := msg.Payload
wm.status = int(d[0])<<24 | int(d[1])<<16 | int(d[2])<<8 | int(d[3])
case "exit-signal":
var sigval struct {
Signal string
CoreDumped bool
Error string
Lang string
}
if err := Unmarshal(msg.Payload, &sigval); err != nil {
return err
}
// Must sanitize strings?
wm.signal = sigval.Signal
wm.msg = sigval.Error
wm.lang = sigval.Lang
default:
// This handles keepalives and matches
// OpenSSH's behaviour.
if msg.WantReply {
msg.Reply(false, nil)
}
}
}
if wm.status == 0 {
return nil
}
if wm.status == -1 {
// exit-status was never sent from server
if wm.signal == "" {
return errors.New("wait: remote command exited without exit status or exit signal")
}
wm.status = 128
if _, ok := signals[Signal(wm.signal)]; ok {
wm.status += signals[Signal(wm.signal)]
}
}
return &ExitError{wm}
}
func (s *Session) stdin() {
if s.stdinpipe {
return
}
var stdin io.Reader
if s.Stdin == nil {
stdin = new(bytes.Buffer)
} else {
r, w := io.Pipe()
go func() {
_, err := io.Copy(w, s.Stdin)
w.CloseWithError(err)
}()
stdin, s.stdinPipeWriter = r, w
}
s.copyFuncs = append(s.copyFuncs, func() error {
_, err := io.Copy(s.ch, stdin)
if err1 := s.ch.CloseWrite(); err == nil && err1 != io.EOF {
err = err1
}
return err
})
}
func (s *Session) stdout() {
if s.stdoutpipe {
return
}
if s.Stdout == nil {
s.Stdout = ioutil.Discard
}
s.copyFuncs = append(s.copyFuncs, func() error {
_, err := io.Copy(s.Stdout, s.ch)
return err
})
}
func (s *Session) stderr() {
if s.stderrpipe {
return
}
if s.Stderr == nil {
s.Stderr = ioutil.Discard
}
s.copyFuncs = append(s.copyFuncs, func() error {
_, err := io.Copy(s.Stderr, s.ch.Stderr())
return err
})
}
// sessionStdin reroutes Close to CloseWrite.
type sessionStdin struct {
io.Writer
ch Channel
}
func (s *sessionStdin) Close() error {
return s.ch.CloseWrite()
}
// StdinPipe returns a pipe that will be connected to the
// remote command's standard input when the command starts.
func (s *Session) StdinPipe() (io.WriteCloser, error) {
if s.Stdin != nil {
return nil, errors.New("ssh: Stdin already set")
}
if s.started {
return nil, errors.New("ssh: StdinPipe after process started")
}
s.stdinpipe = true
return &sessionStdin{s.ch, s.ch}, nil
}
// StdoutPipe returns a pipe that will be connected to the
// remote command's standard output when the command starts.
// There is a fixed amount of buffering that is shared between
// stdout and stderr streams. If the StdoutPipe reader is
// not serviced fast enough it may eventually cause the
// remote command to block.
func (s *Session) StdoutPipe() (io.Reader, error) {
if s.Stdout != nil {
return nil, errors.New("ssh: Stdout already set")
}
if s.started {
return nil, errors.New("ssh: StdoutPipe after process started")
}
s.stdoutpipe = true
return s.ch, nil
}
// StderrPipe returns a pipe that will be connected to the
// remote command's standard error when the command starts.
// There is a fixed amount of buffering that is shared between
// stdout and stderr streams. If the StderrPipe reader is
// not serviced fast enough it may eventually cause the
// remote command to block.
func (s *Session) StderrPipe() (io.Reader, error) {
if s.Stderr != nil {
return nil, errors.New("ssh: Stderr already set")
}
if s.started {
return nil, errors.New("ssh: StderrPipe after process started")
}
s.stderrpipe = true
return s.ch.Stderr(), nil
}
// newSession returns a new interactive session on the remote host.
func newSession(ch Channel, reqs <-chan *Request) (*Session, error) {
s := &Session{
ch: ch,
}
s.exitStatus = make(chan error, 1)
go func() {
s.exitStatus <- s.wait(reqs)
}()
return s, nil
}
// An ExitError reports unsuccessful completion of a remote command.
type ExitError struct {
Waitmsg
}
func (e *ExitError) Error() string {
return e.Waitmsg.String()
}
// Waitmsg stores the information about an exited remote command
// as reported by Wait.
type Waitmsg struct {
status int
signal string
msg string
lang string
}
// ExitStatus returns the exit status of the remote command.
func (w Waitmsg) ExitStatus() int {
return w.status
}
// Signal returns the exit signal of the remote command if
// it was terminated violently.
func (w Waitmsg) Signal() string {
return w.signal
}
// Msg returns the exit message given by the remote command
func (w Waitmsg) Msg() string {
return w.msg
}
// Lang returns the language tag. See RFC 3066
func (w Waitmsg) Lang() string {
return w.lang
}
func (w Waitmsg) String() string {
return fmt.Sprintf("Process exited with: %v. Reason was: %v (%v)", w.status, w.msg, w.signal)
}

774
modules/crypto/ssh/session_test.go
Unescape View File

@ -0,0 +1,774 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
// Session tests.
import (
"bytes"
crypto_rand "crypto/rand"
"errors"
"io"
"io/ioutil"
"math/rand"
"net"
"testing"
"github.com/gogits/gogs/modules/ssh/terminal"
)
type serverType func(Channel, <-chan *Request, *testing.T)
// dial constructs a new test server and returns a *ClientConn.
func dial(handler serverType, t *testing.T) *Client {
c1, c2, err := netPipe()
if err != nil {
t.Fatalf("netPipe: %v", err)
}
go func() {
defer c1.Close()
conf := ServerConfig{
NoClientAuth: true,
}
conf.AddHostKey(testSigners["rsa"])
_, chans, reqs, err := NewServerConn(c1, &conf)
if err != nil {
t.Fatalf("Unable to handshake: %v", err)
}
go DiscardRequests(reqs)
for newCh := range chans {
if newCh.ChannelType() != "session" {
newCh.Reject(UnknownChannelType, "unknown channel type")
continue
}
ch, inReqs, err := newCh.Accept()
if err != nil {
t.Errorf("Accept: %v", err)
continue
}
go func() {
handler(ch, inReqs, t)
}()
}
}()
config := &ClientConfig{
User: "testuser",
}
conn, chans, reqs, err := NewClientConn(c2, "", config)
if err != nil {
t.Fatalf("unable to dial remote side: %v", err)
}
return NewClient(conn, chans, reqs)
}
// Test a simple string is returned to session.Stdout.
func TestSessionShell(t *testing.T) {
conn := dial(shellHandler, t)
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatalf("Unable to request new session: %v", err)
}
defer session.Close()
stdout := new(bytes.Buffer)
session.Stdout = stdout
if err := session.Shell(); err != nil {
t.Fatalf("Unable to execute command: %s", err)
}
if err := session.Wait(); err != nil {
t.Fatalf("Remote command did not exit cleanly: %v", err)
}
actual := stdout.String()
if actual != "golang" {
t.Fatalf("Remote shell did not return expected string: expected=golang, actual=%s", actual)
}
}
// TODO(dfc) add support for Std{in,err}Pipe when the Server supports it.
// Test a simple string is returned via StdoutPipe.
func TestSessionStdoutPipe(t *testing.T) {
conn := dial(shellHandler, t)
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatalf("Unable to request new session: %v", err)
}
defer session.Close()
stdout, err := session.StdoutPipe()
if err != nil {
t.Fatalf("Unable to request StdoutPipe(): %v", err)
}
var buf bytes.Buffer
if err := session.Shell(); err != nil {
t.Fatalf("Unable to execute command: %v", err)
}
done := make(chan bool, 1)
go func() {
if _, err := io.Copy(&buf, stdout); err != nil {
t.Errorf("Copy of stdout failed: %v", err)
}
done <- true
}()
if err := session.Wait(); err != nil {
t.Fatalf("Remote command did not exit cleanly: %v", err)
}
<-done
actual := buf.String()
if actual != "golang" {
t.Fatalf("Remote shell did not return expected string: expected=golang, actual=%s", actual)
}
}
// Test that a simple string is returned via the Output helper,
// and that stderr is discarded.
func TestSessionOutput(t *testing.T) {
conn := dial(fixedOutputHandler, t)
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatalf("Unable to request new session: %v", err)
}
defer session.Close()
buf, err := session.Output("") // cmd is ignored by fixedOutputHandler
if err != nil {
t.Error("Remote command did not exit cleanly:", err)
}
w := "this-is-stdout."
g := string(buf)
if g != w {
t.Error("Remote command did not return expected string:")
t.Logf("want %q", w)
t.Logf("got %q", g)
}
}
// Test that both stdout and stderr are returned
// via the CombinedOutput helper.
func TestSessionCombinedOutput(t *testing.T) {
conn := dial(fixedOutputHandler, t)
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatalf("Unable to request new session: %v", err)
}
defer session.Close()
buf, err := session.CombinedOutput("") // cmd is ignored by fixedOutputHandler
if err != nil {
t.Error("Remote command did not exit cleanly:", err)
}
const stdout = "this-is-stdout."
const stderr = "this-is-stderr."
g := string(buf)
if g != stdout+stderr && g != stderr+stdout {
t.Error("Remote command did not return expected string:")
t.Logf("want %q, or %q", stdout+stderr, stderr+stdout)
t.Logf("got %q", g)
}
}
// Test non-0 exit status is returned correctly.
func TestExitStatusNonZero(t *testing.T) {
conn := dial(exitStatusNonZeroHandler, t)
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatalf("Unable to request new session: %v", err)
}
defer session.Close()
if err := session.Shell(); err != nil {
t.Fatalf("Unable to execute command: %v", err)
}
err = session.Wait()
if err == nil {
t.Fatalf("expected command to fail but it didn't")
}
e, ok := err.(*ExitError)
if !ok {
t.Fatalf("expected *ExitError but got %T", err)
}
if e.ExitStatus() != 15 {
t.Fatalf("expected command to exit with 15 but got %v", e.ExitStatus())
}
}
// Test 0 exit status is returned correctly.
func TestExitStatusZero(t *testing.T) {
conn := dial(exitStatusZeroHandler, t)
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatalf("Unable to request new session: %v", err)
}
defer session.Close()
if err := session.Shell(); err != nil {
t.Fatalf("Unable to execute command: %v", err)
}
err = session.Wait()
if err != nil {
t.Fatalf("expected nil but got %v", err)
}
}
// Test exit signal and status are both returned correctly.
func TestExitSignalAndStatus(t *testing.T) {
conn := dial(exitSignalAndStatusHandler, t)
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatalf("Unable to request new session: %v", err)
}
defer session.Close()
if err := session.Shell(); err != nil {
t.Fatalf("Unable to execute command: %v", err)
}
err = session.Wait()
if err == nil {
t.Fatalf("expected command to fail but it didn't")
}
e, ok := err.(*ExitError)
if !ok {
t.Fatalf("expected *ExitError but got %T", err)
}
if e.Signal() != "TERM" || e.ExitStatus() != 15 {
t.Fatalf("expected command to exit with signal TERM and status 15 but got signal %s and status %v", e.Signal(), e.ExitStatus())
}
}
// Test exit signal and status are both returned correctly.
func TestKnownExitSignalOnly(t *testing.T) {
conn := dial(exitSignalHandler, t)
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatalf("Unable to request new session: %v", err)
}
defer session.Close()
if err := session.Shell(); err != nil {
t.Fatalf("Unable to execute command: %v", err)
}
err = session.Wait()
if err == nil {
t.Fatalf("expected command to fail but it didn't")
}
e, ok := err.(*ExitError)
if !ok {
t.Fatalf("expected *ExitError but got %T", err)
}
if e.Signal() != "TERM" || e.ExitStatus() != 143 {
t.Fatalf("expected command to exit with signal TERM and status 143 but got signal %s and status %v", e.Signal(), e.ExitStatus())
}
}
// Test exit signal and status are both returned correctly.
func TestUnknownExitSignal(t *testing.T) {
conn := dial(exitSignalUnknownHandler, t)
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatalf("Unable to request new session: %v", err)
}
defer session.Close()
if err := session.Shell(); err != nil {
t.Fatalf("Unable to execute command: %v", err)
}
err = session.Wait()
if err == nil {
t.Fatalf("expected command to fail but it didn't")
}
e, ok := err.(*ExitError)
if !ok {
t.Fatalf("expected *ExitError but got %T", err)
}
if e.Signal() != "SYS" || e.ExitStatus() != 128 {
t.Fatalf("expected command to exit with signal SYS and status 128 but got signal %s and status %v", e.Signal(), e.ExitStatus())
}
}
// Test WaitMsg is not returned if the channel closes abruptly.
func TestExitWithoutStatusOrSignal(t *testing.T) {
conn := dial(exitWithoutSignalOrStatus, t)
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatalf("Unable to request new session: %v", err)
}
defer session.Close()
if err := session.Shell(); err != nil {
t.Fatalf("Unable to execute command: %v", err)
}
err = session.Wait()
if err == nil {
t.Fatalf("expected command to fail but it didn't")
}
_, ok := err.(*ExitError)
if ok {
// you can't actually test for errors.errorString
// because it's not exported.
t.Fatalf("expected *errorString but got %T", err)
}
}
// windowTestBytes is the number of bytes that we'll send to the SSH server.
const windowTestBytes = 16000 * 200
// TestServerWindow writes random data to the server. The server is expected to echo
// the same data back, which is compared against the original.
func TestServerWindow(t *testing.T) {
origBuf := bytes.NewBuffer(make([]byte, 0, windowTestBytes))
io.CopyN(origBuf, crypto_rand.Reader, windowTestBytes)
origBytes := origBuf.Bytes()
conn := dial(echoHandler, t)
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatal(err)
}
defer session.Close()
result := make(chan []byte)
go func() {
defer close(result)
echoedBuf := bytes.NewBuffer(make([]byte, 0, windowTestBytes))
serverStdout, err := session.StdoutPipe()
if err != nil {
t.Errorf("StdoutPipe failed: %v", err)
return
}
n, err := copyNRandomly("stdout", echoedBuf, serverStdout, windowTestBytes)
if err != nil && err != io.EOF {
t.Errorf("Read only %d bytes from server, expected %d: %v", n, windowTestBytes, err)
}
result <- echoedBuf.Bytes()
}()
serverStdin, err := session.StdinPipe()
if err != nil {
t.Fatalf("StdinPipe failed: %v", err)
}
written, err := copyNRandomly("stdin", serverStdin, origBuf, windowTestBytes)
if err != nil {
t.Fatalf("failed to copy origBuf to serverStdin: %v", err)
}
if written != windowTestBytes {
t.Fatalf("Wrote only %d of %d bytes to server", written, windowTestBytes)
}
echoedBytes := <-result
if !bytes.Equal(origBytes, echoedBytes) {
t.Fatalf("Echoed buffer differed from original, orig %d, echoed %d", len(origBytes), len(echoedBytes))
}
}
// Verify the client can handle a keepalive packet from the server.
func TestClientHandlesKeepalives(t *testing.T) {
conn := dial(channelKeepaliveSender, t)
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatal(err)
}
defer session.Close()
if err := session.Shell(); err != nil {
t.Fatalf("Unable to execute command: %v", err)
}
err = session.Wait()
if err != nil {
t.Fatalf("expected nil but got: %v", err)
}
}
type exitStatusMsg struct {
Status uint32
}
type exitSignalMsg struct {
Signal string
CoreDumped bool
Errmsg string
Lang string
}
func handleTerminalRequests(in <-chan *Request) {
for req := range in {
ok := false
switch req.Type {
case "shell":
ok = true
if len(req.Payload) > 0 {
// We don't accept any commands, only the default shell.
ok = false
}
case "env":
ok = true
}
req.Reply(ok, nil)
}
}
func newServerShell(ch Channel, in <-chan *Request, prompt string) *terminal.Terminal {
term := terminal.NewTerminal(ch, prompt)
go handleTerminalRequests(in)
return term
}
func exitStatusZeroHandler(ch Channel, in <-chan *Request, t *testing.T) {
defer ch.Close()
// this string is returned to stdout
shell := newServerShell(ch, in, "> ")
readLine(shell, t)
sendStatus(0, ch, t)
}
func exitStatusNonZeroHandler(ch Channel, in <-chan *Request, t *testing.T) {
defer ch.Close()
shell := newServerShell(ch, in, "> ")
readLine(shell, t)
sendStatus(15, ch, t)
}
func exitSignalAndStatusHandler(ch Channel, in <-chan *Request, t *testing.T) {
defer ch.Close()
shell := newServerShell(ch, in, "> ")
readLine(shell, t)
sendStatus(15, ch, t)
sendSignal("TERM", ch, t)
}
func exitSignalHandler(ch Channel, in <-chan *Request, t *testing.T) {
defer ch.Close()
shell := newServerShell(ch, in, "> ")
readLine(shell, t)
sendSignal("TERM", ch, t)
}
func exitSignalUnknownHandler(ch Channel, in <-chan *Request, t *testing.T) {
defer ch.Close()
shell := newServerShell(ch, in, "> ")
readLine(shell, t)
sendSignal("SYS", ch, t)
}
func exitWithoutSignalOrStatus(ch Channel, in <-chan *Request, t *testing.T) {
defer ch.Close()
shell := newServerShell(ch, in, "> ")
readLine(shell, t)
}
func shellHandler(ch Channel, in <-chan *Request, t *testing.T) {
defer ch.Close()
// this string is returned to stdout
shell := newServerShell(ch, in, "golang")
readLine(shell, t)
sendStatus(0, ch, t)
}
// Ignores the command, writes fixed strings to stderr and stdout.
// Strings are "this-is-stdout." and "this-is-stderr.".
func fixedOutputHandler(ch Channel, in <-chan *Request, t *testing.T) {
defer ch.Close()
_, err := ch.Read(nil)
req, ok := <-in
if !ok {
t.Fatalf("error: expected channel request, got: %#v", err)
return
}
// ignore request, always send some text
req.Reply(true, nil)
_, err = io.WriteString(ch, "this-is-stdout.")
if err != nil {
t.Fatalf("error writing on server: %v", err)
}
_, err = io.WriteString(ch.Stderr(), "this-is-stderr.")
if err != nil {
t.Fatalf("error writing on server: %v", err)
}
sendStatus(0, ch, t)
}
func readLine(shell *terminal.Terminal, t *testing.T) {
if _, err := shell.ReadLine(); err != nil && err != io.EOF {
t.Errorf("unable to read line: %v", err)
}
}
func sendStatus(status uint32, ch Channel, t *testing.T) {
msg := exitStatusMsg{
Status: status,
}
if _, err := ch.SendRequest("exit-status", false, Marshal(&msg)); err != nil {
t.Errorf("unable to send status: %v", err)
}
}
func sendSignal(signal string, ch Channel, t *testing.T) {
sig := exitSignalMsg{
Signal: signal,
CoreDumped: false,
Errmsg: "Process terminated",
Lang: "en-GB-oed",
}
if _, err := ch.SendRequest("exit-signal", false, Marshal(&sig)); err != nil {
t.Errorf("unable to send signal: %v", err)
}
}
func discardHandler(ch Channel, t *testing.T) {
defer ch.Close()
io.Copy(ioutil.Discard, ch)
}
func echoHandler(ch Channel, in <-chan *Request, t *testing.T) {
defer ch.Close()
if n, err := copyNRandomly("echohandler", ch, ch, windowTestBytes); err != nil {
t.Errorf("short write, wrote %d, expected %d: %v ", n, windowTestBytes, err)
}
}
// copyNRandomly copies n bytes from src to dst. It uses a variable, and random,
// buffer size to exercise more code paths.
func copyNRandomly(title string, dst io.Writer, src io.Reader, n int) (int, error) {
var (
buf = make([]byte, 32*1024)
written int
remaining = n
)
for remaining > 0 {
l := rand.Intn(1 << 15)
if remaining < l {
l = remaining
}
nr, er := src.Read(buf[:l])
nw, ew := dst.Write(buf[:nr])
remaining -= nw
written += nw
if ew != nil {
return written, ew
}
if nr != nw {
return written, io.ErrShortWrite
}
if er != nil && er != io.EOF {
return written, er
}
}
return written, nil
}
func channelKeepaliveSender(ch Channel, in <-chan *Request, t *testing.T) {
defer ch.Close()
shell := newServerShell(ch, in, "> ")
readLine(shell, t)
if _, err := ch.SendRequest("keepalive@openssh.com", true, nil); err != nil {
t.Errorf("unable to send channel keepalive request: %v", err)
}
sendStatus(0, ch, t)
}
func TestClientWriteEOF(t *testing.T) {
conn := dial(simpleEchoHandler, t)
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatal(err)
}
defer session.Close()
stdin, err := session.StdinPipe()
if err != nil {
t.Fatalf("StdinPipe failed: %v", err)
}
stdout, err := session.StdoutPipe()
if err != nil {
t.Fatalf("StdoutPipe failed: %v", err)
}
data := []byte(`0000`)
_, err = stdin.Write(data)
if err != nil {
t.Fatalf("Write failed: %v", err)
}
stdin.Close()
res, err := ioutil.ReadAll(stdout)
if err != nil {
t.Fatalf("Read failed: %v", err)
}
if !bytes.Equal(data, res) {
t.Fatalf("Read differed from write, wrote: %v, read: %v", data, res)
}
}
func simpleEchoHandler(ch Channel, in <-chan *Request, t *testing.T) {
defer ch.Close()
data, err := ioutil.ReadAll(ch)
if err != nil {
t.Errorf("handler read error: %v", err)
}
_, err = ch.Write(data)
if err != nil {
t.Errorf("handler write error: %v", err)
}
}
func TestSessionID(t *testing.T) {
c1, c2, err := netPipe()
if err != nil {
t.Fatalf("netPipe: %v", err)
}
defer c1.Close()
defer c2.Close()
serverID := make(chan []byte, 1)
clientID := make(chan []byte, 1)
serverConf := &ServerConfig{
NoClientAuth: true,
}
serverConf.AddHostKey(testSigners["ecdsa"])
clientConf := &ClientConfig{
User: "user",
}
go func() {
conn, chans, reqs, err := NewServerConn(c1, serverConf)
if err != nil {
t.Fatalf("server handshake: %v", err)
}
serverID <- conn.SessionID()
go DiscardRequests(reqs)
for ch := range chans {
ch.Reject(Prohibited, "")
}
}()
go func() {
conn, chans, reqs, err := NewClientConn(c2, "", clientConf)
if err != nil {
t.Fatalf("client handshake: %v", err)
}
clientID <- conn.SessionID()
go DiscardRequests(reqs)
for ch := range chans {
ch.Reject(Prohibited, "")
}
}()
s := <-serverID
c := <-clientID
if bytes.Compare(s, c) != 0 {
t.Errorf("server session ID (%x) != client session ID (%x)", s, c)
} else if len(s) == 0 {
t.Errorf("client and server SessionID were empty.")
}
}
type noReadConn struct {
readSeen bool
net.Conn
}
func (c *noReadConn) Close() error {
return nil
}
func (c *noReadConn) Read(b []byte) (int, error) {
c.readSeen = true
return 0, errors.New("noReadConn error")
}
func TestInvalidServerConfiguration(t *testing.T) {
c1, c2, err := netPipe()
if err != nil {
t.Fatalf("netPipe: %v", err)
}
defer c1.Close()
defer c2.Close()
serveConn := noReadConn{Conn: c1}
serverConf := &ServerConfig{}
NewServerConn(&serveConn, serverConf)
if serveConn.readSeen {
t.Fatalf("NewServerConn attempted to Read() from Conn while configuration is missing host key")
}
serverConf.AddHostKey(testSigners["ecdsa"])
NewServerConn(&serveConn, serverConf)
if serveConn.readSeen {
t.Fatalf("NewServerConn attempted to Read() from Conn while configuration is missing authentication method")
}
}
func TestHostKeyAlgorithms(t *testing.T) {
serverConf := &ServerConfig{
NoClientAuth: true,
}
serverConf.AddHostKey(testSigners["rsa"])
serverConf.AddHostKey(testSigners["ecdsa"])
connect := func(clientConf *ClientConfig, want string) {
var alg string
clientConf.HostKeyCallback = func(h string, a net.Addr, key PublicKey) error {
alg = key.Type()
return nil
}
c1, c2, err := netPipe()
if err != nil {
t.Fatalf("netPipe: %v", err)
}
defer c1.Close()
defer c2.Close()
go NewServerConn(c1, serverConf)
_, _, _, err = NewClientConn(c2, "", clientConf)
if err != nil {
t.Fatalf("NewClientConn: %v", err)
}
if alg != want {
t.Errorf("selected key algorithm %s, want %s", alg, want)
}
}
// By default, we get the preferred algorithm, which is ECDSA 256.
clientConf := &ClientConfig{}
connect(clientConf, KeyAlgoECDSA256)
// Client asks for RSA explicitly.
clientConf.HostKeyAlgorithms = []string{KeyAlgoRSA}
connect(clientConf, KeyAlgoRSA)
c1, c2, err := netPipe()
if err != nil {
t.Fatalf("netPipe: %v", err)
}
defer c1.Close()
defer c2.Close()
go NewServerConn(c1, serverConf)
clientConf.HostKeyAlgorithms = []string{"nonexistent-hostkey-algo"}
_, _, _, err = NewClientConn(c2, "", clientConf)
if err == nil {
t.Fatal("succeeded connecting with unknown hostkey algorithm")
}
}

407
modules/crypto/ssh/tcpip.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"errors"
"fmt"
"io"
"math/rand"
"net"
"strconv"
"strings"
"sync"
"time"
)
// Listen requests the remote peer open a listening socket on
// addr. Incoming connections will be available by calling Accept on
// the returned net.Listener. The listener must be serviced, or the
// SSH connection may hang.
func (c *Client) Listen(n, addr string) (net.Listener, error) {
laddr, err := net.ResolveTCPAddr(n, addr)
if err != nil {
return nil, err
}
return c.ListenTCP(laddr)
}
// Automatic port allocation is broken with OpenSSH before 6.0. See
// also https://bugzilla.mindrot.org/show_bug.cgi?id=2017. In
// particular, OpenSSH 5.9 sends a channelOpenMsg with port number 0,
// rather than the actual port number. This means you can never open
// two different listeners with auto allocated ports. We work around
// this by trying explicit ports until we succeed.
const openSSHPrefix = "OpenSSH_"
var portRandomizer = rand.New(rand.NewSource(time.Now().UnixNano()))
// isBrokenOpenSSHVersion returns true if the given version string
// specifies a version of OpenSSH that is known to have a bug in port
// forwarding.
func isBrokenOpenSSHVersion(versionStr string) bool {
i := strings.Index(versionStr, openSSHPrefix)
if i < 0 {
return false
}
i += len(openSSHPrefix)
j := i
for ; j < len(versionStr); j++ {
if versionStr[j] < '0' || versionStr[j] > '9' {
break
}
}
version, _ := strconv.Atoi(versionStr[i:j])
return version < 6
}
// autoPortListenWorkaround simulates automatic port allocation by
// trying random ports repeatedly.
func (c *Client) autoPortListenWorkaround(laddr *net.TCPAddr) (net.Listener, error) {
var sshListener net.Listener
var err error
const tries = 10
for i := 0; i < tries; i++ {
addr := *laddr
addr.Port = 1024 + portRandomizer.Intn(60000)
sshListener, err = c.ListenTCP(&addr)
if err == nil {
laddr.Port = addr.Port
return sshListener, err
}
}
return nil, fmt.Errorf("ssh: listen on random port failed after %d tries: %v", tries, err)
}
// RFC 4254 7.1
type channelForwardMsg struct {
addr string
rport uint32
}
// ListenTCP requests the remote peer open a listening socket
// on laddr. Incoming connections will be available by calling
// Accept on the returned net.Listener.
func (c *Client) ListenTCP(laddr *net.TCPAddr) (net.Listener, error) {
if laddr.Port == 0 && isBrokenOpenSSHVersion(string(c.ServerVersion())) {
return c.autoPortListenWorkaround(laddr)
}
m := channelForwardMsg{
laddr.IP.String(),
uint32(laddr.Port),
}
// send message
ok, resp, err := c.SendRequest("tcpip-forward", true, Marshal(&m))
if err != nil {
return nil, err
}
if !ok {
return nil, errors.New("ssh: tcpip-forward request denied by peer")
}
// If the original port was 0, then the remote side will
// supply a real port number in the response.
if laddr.Port == 0 {
var p struct {
Port uint32
}
if err := Unmarshal(resp, &p); err != nil {
return nil, err
}
laddr.Port = int(p.Port)
}
// Register this forward, using the port number we obtained.
ch := c.forwards.add(*laddr)
return &tcpListener{laddr, c, ch}, nil
}
// forwardList stores a mapping between remote
// forward requests and the tcpListeners.
type forwardList struct {
sync.Mutex
entries []forwardEntry
}
// forwardEntry represents an established mapping of a laddr on a
// remote ssh server to a channel connected to a tcpListener.
type forwardEntry struct {
laddr net.TCPAddr
c chan forward
}
// forward represents an incoming forwarded tcpip connection. The
// arguments to add/remove/lookup should be address as specified in
// the original forward-request.
type forward struct {
newCh NewChannel // the ssh client channel underlying this forward
raddr *net.TCPAddr // the raddr of the incoming connection
}
func (l *forwardList) add(addr net.TCPAddr) chan forward {
l.Lock()
defer l.Unlock()
f := forwardEntry{
addr,
make(chan forward, 1),
}
l.entries = append(l.entries, f)
return f.c
}
// See RFC 4254, section 7.2
type forwardedTCPPayload struct {
Addr string
Port uint32
OriginAddr string
OriginPort uint32
}
// parseTCPAddr parses the originating address from the remote into a *net.TCPAddr.
func parseTCPAddr(addr string, port uint32) (*net.TCPAddr, error) {
if port == 0 || port > 65535 {
return nil, fmt.Errorf("ssh: port number out of range: %d", port)
}
ip := net.ParseIP(string(addr))
if ip == nil {
return nil, fmt.Errorf("ssh: cannot parse IP address %q", addr)
}
return &net.TCPAddr{IP: ip, Port: int(port)}, nil
}
func (l *forwardList) handleChannels(in <-chan NewChannel) {
for ch := range in {
var payload forwardedTCPPayload
if err := Unmarshal(ch.ExtraData(), &payload); err != nil {
ch.Reject(ConnectionFailed, "could not parse forwarded-tcpip payload: "+err.Error())
continue
}
// RFC 4254 section 7.2 specifies that incoming
// addresses should list the address, in string
// format. It is implied that this should be an IP
// address, as it would be impossible to connect to it
// otherwise.
laddr, err := parseTCPAddr(payload.Addr, payload.Port)
if err != nil {
ch.Reject(ConnectionFailed, err.Error())
continue
}
raddr, err := parseTCPAddr(payload.OriginAddr, payload.OriginPort)
if err != nil {
ch.Reject(ConnectionFailed, err.Error())
continue
}
if ok := l.forward(*laddr, *raddr, ch); !ok {
// Section 7.2, implementations MUST reject spurious incoming
// connections.
ch.Reject(Prohibited, "no forward for address")
continue
}
}
}
// remove removes the forward entry, and the channel feeding its
// listener.
func (l *forwardList) remove(addr net.TCPAddr) {
l.Lock()
defer l.Unlock()
for i, f := range l.entries {
if addr.IP.Equal(f.laddr.IP) && addr.Port == f.laddr.Port {
l.entries = append(l.entries[:i], l.entries[i+1:]...)
close(f.c)
return
}
}
}
// closeAll closes and clears all forwards.
func (l *forwardList) closeAll() {
l.Lock()
defer l.Unlock()
for _, f := range l.entries {
close(f.c)
}
l.entries = nil
}
func (l *forwardList) forward(laddr, raddr net.TCPAddr, ch NewChannel) bool {
l.Lock()
defer l.Unlock()
for _, f := range l.entries {
if laddr.IP.Equal(f.laddr.IP) && laddr.Port == f.laddr.Port {
f.c <- forward{ch, &raddr}
return true
}
}
return false
}
type tcpListener struct {
laddr *net.TCPAddr
conn *Client
in <-chan forward
}
// Accept waits for and returns the next connection to the listener.
func (l *tcpListener) Accept() (net.Conn, error) {
s, ok := <-l.in
if !ok {
return nil, io.EOF
}
ch, incoming, err := s.newCh.Accept()
if err != nil {
return nil, err
}
go DiscardRequests(incoming)
return &tcpChanConn{
Channel: ch,
laddr: l.laddr,
raddr: s.raddr,
}, nil
}
// Close closes the listener.
func (l *tcpListener) Close() error {
m := channelForwardMsg{
l.laddr.IP.String(),
uint32(l.laddr.Port),
}
// this also closes the listener.
l.conn.forwards.remove(*l.laddr)
ok, _, err := l.conn.SendRequest("cancel-tcpip-forward", true, Marshal(&m))
if err == nil && !ok {
err = errors.New("ssh: cancel-tcpip-forward failed")
}
return err
}
// Addr returns the listener's network address.
func (l *tcpListener) Addr() net.Addr {
return l.laddr
}
// Dial initiates a connection to the addr from the remote host.
// The resulting connection has a zero LocalAddr() and RemoteAddr().
func (c *Client) Dial(n, addr string) (net.Conn, error) {
// Parse the address into host and numeric port.
host, portString, err := net.SplitHostPort(addr)
if err != nil {
return nil, err
}
port, err := strconv.ParseUint(portString, 10, 16)
if err != nil {
return nil, err
}
// Use a zero address for local and remote address.
zeroAddr := &net.TCPAddr{
IP: net.IPv4zero,
Port: 0,
}
ch, err := c.dial(net.IPv4zero.String(), 0, host, int(port))
if err != nil {
return nil, err
}
return &tcpChanConn{
Channel: ch,
laddr: zeroAddr,
raddr: zeroAddr,
}, nil
}
// DialTCP connects to the remote address raddr on the network net,
// which must be "tcp", "tcp4", or "tcp6". If laddr is not nil, it is used
// as the local address for the connection.
func (c *Client) DialTCP(n string, laddr, raddr *net.TCPAddr) (net.Conn, error) {
if laddr == nil {
laddr = &net.TCPAddr{
IP: net.IPv4zero,
Port: 0,
}
}
ch, err := c.dial(laddr.IP.String(), laddr.Port, raddr.IP.String(), raddr.Port)
if err != nil {
return nil, err
}
return &tcpChanConn{
Channel: ch,
laddr: laddr,
raddr: raddr,
}, nil
}
// RFC 4254 7.2
type channelOpenDirectMsg struct {
raddr string
rport uint32
laddr string
lport uint32
}
func (c *Client) dial(laddr string, lport int, raddr string, rport int) (Channel, error) {
msg := channelOpenDirectMsg{
raddr: raddr,
rport: uint32(rport),
laddr: laddr,
lport: uint32(lport),
}
ch, in, err := c.OpenChannel("direct-tcpip", Marshal(&msg))
if err != nil {
return nil, err
}
go DiscardRequests(in)
return ch, err
}
type tcpChan struct {
Channel // the backing channel
}
// tcpChanConn fulfills the net.Conn interface without
// the tcpChan having to hold laddr or raddr directly.
type tcpChanConn struct {
Channel
laddr, raddr net.Addr
}
// LocalAddr returns the local network address.
func (t *tcpChanConn) LocalAddr() net.Addr {
return t.laddr
}
// RemoteAddr returns the remote network address.
func (t *tcpChanConn) RemoteAddr() net.Addr {
return t.raddr
}
// SetDeadline sets the read and write deadlines associated
// with the connection.
func (t *tcpChanConn) SetDeadline(deadline time.Time) error {
if err := t.SetReadDeadline(deadline); err != nil {
return err
}
return t.SetWriteDeadline(deadline)
}
// SetReadDeadline sets the read deadline.
// A zero value for t means Read will not time out.
// After the deadline, the error from Read will implement net.Error
// with Timeout() == true.
func (t *tcpChanConn) SetReadDeadline(deadline time.Time) error {
return errors.New("ssh: tcpChan: deadline not supported")
}
// SetWriteDeadline exists to satisfy the net.Conn interface
// but is not implemented by this type. It always returns an error.
func (t *tcpChanConn) SetWriteDeadline(deadline time.Time) error {
return errors.New("ssh: tcpChan: deadline not supported")
}

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modules/crypto/ssh/tcpip_test.go
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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"testing"
)
func TestAutoPortListenBroken(t *testing.T) {
broken := "SSH-2.0-OpenSSH_5.9hh11"
works := "SSH-2.0-OpenSSH_6.1"
if !isBrokenOpenSSHVersion(broken) {
t.Errorf("version %q not marked as broken", broken)
}
if isBrokenOpenSSHVersion(works) {
t.Errorf("version %q marked as broken", works)
}
}

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modules/crypto/ssh/terminal/terminal.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package terminal
import (
"bytes"
"io"
"sync"
"unicode/utf8"
)
// EscapeCodes contains escape sequences that can be written to the terminal in
// order to achieve different styles of text.
type EscapeCodes struct {
// Foreground colors
Black, Red, Green, Yellow, Blue, Magenta, Cyan, White []byte
// Reset all attributes
Reset []byte
}
var vt100EscapeCodes = EscapeCodes{
Black: []byte{keyEscape, '[', '3', '0', 'm'},
Red: []byte{keyEscape, '[', '3', '1', 'm'},
Green: []byte{keyEscape, '[', '3', '2', 'm'},
Yellow: []byte{keyEscape, '[', '3', '3', 'm'},
Blue: []byte{keyEscape, '[', '3', '4', 'm'},
Magenta: []byte{keyEscape, '[', '3', '5', 'm'},
Cyan: []byte{keyEscape, '[', '3', '6', 'm'},
White: []byte{keyEscape, '[', '3', '7', 'm'},
Reset: []byte{keyEscape, '[', '0', 'm'},
}
// Terminal contains the state for running a VT100 terminal that is capable of
// reading lines of input.
type Terminal struct {
// AutoCompleteCallback, if non-null, is called for each keypress with
// the full input line and the current position of the cursor (in
// bytes, as an index into |line|). If it returns ok=false, the key
// press is processed normally. Otherwise it returns a replacement line
// and the new cursor position.
AutoCompleteCallback func(line string, pos int, key rune) (newLine string, newPos int, ok bool)
// Escape contains a pointer to the escape codes for this terminal.
// It's always a valid pointer, although the escape codes themselves
// may be empty if the terminal doesn't support them.
Escape *EscapeCodes
// lock protects the terminal and the state in this object from
// concurrent processing of a key press and a Write() call.
lock sync.Mutex
c io.ReadWriter
prompt []rune
// line is the current line being entered.
line []rune
// pos is the logical position of the cursor in line
pos int
// echo is true if local echo is enabled
echo bool
// pasteActive is true iff there is a bracketed paste operation in
// progress.
pasteActive bool
// cursorX contains the current X value of the cursor where the left
// edge is 0. cursorY contains the row number where the first row of
// the current line is 0.
cursorX, cursorY int
// maxLine is the greatest value of cursorY so far.
maxLine int
termWidth, termHeight int
// outBuf contains the terminal data to be sent.
outBuf []byte
// remainder contains the remainder of any partial key sequences after
// a read. It aliases into inBuf.
remainder []byte
inBuf [256]byte
// history contains previously entered commands so that they can be
// accessed with the up and down keys.
history stRingBuffer
// historyIndex stores the currently accessed history entry, where zero
// means the immediately previous entry.
historyIndex int
// When navigating up and down the history it's possible to return to
// the incomplete, initial line. That value is stored in
// historyPending.
historyPending string
}
// NewTerminal runs a VT100 terminal on the given ReadWriter. If the ReadWriter is
// a local terminal, that terminal must first have been put into raw mode.
// prompt is a string that is written at the start of each input line (i.e.
// "> ").
func NewTerminal(c io.ReadWriter, prompt string) *Terminal {
return &Terminal{
Escape: &vt100EscapeCodes,
c: c,
prompt: []rune(prompt),
termWidth: 80,
termHeight: 24,
echo: true,
historyIndex: -1,
}
}
const (
keyCtrlD = 4
keyCtrlU = 21
keyEnter = '\r'
keyEscape = 27
keyBackspace = 127
keyUnknown = 0xd800 /* UTF-16 surrogate area */ + iota
keyUp
keyDown
keyLeft
keyRight
keyAltLeft
keyAltRight
keyHome
keyEnd
keyDeleteWord
keyDeleteLine
keyClearScreen
keyPasteStart
keyPasteEnd
)
var pasteStart = []byte{keyEscape, '[', '2', '0', '0', '~'}
var pasteEnd = []byte{keyEscape, '[', '2', '0', '1', '~'}
// bytesToKey tries to parse a key sequence from b. If successful, it returns
// the key and the remainder of the input. Otherwise it returns utf8.RuneError.
func bytesToKey(b []byte, pasteActive bool) (rune, []byte) {
if len(b) == 0 {
return utf8.RuneError, nil
}
if !pasteActive {
switch b[0] {
case 1: // ^A
return keyHome, b[1:]
case 5: // ^E
return keyEnd, b[1:]
case 8: // ^H
return keyBackspace, b[1:]
case 11: // ^K
return keyDeleteLine, b[1:]
case 12: // ^L
return keyClearScreen, b[1:]
case 23: // ^W
return keyDeleteWord, b[1:]
}
}
if b[0] != keyEscape {
if !utf8.FullRune(b) {
return utf8.RuneError, b
}
r, l := utf8.DecodeRune(b)
return r, b[l:]
}
if !pasteActive && len(b) >= 3 && b[0] == keyEscape && b[1] == '[' {
switch b[2] {
case 'A':
return keyUp, b[3:]
case 'B':
return keyDown, b[3:]
case 'C':
return keyRight, b[3:]
case 'D':
return keyLeft, b[3:]
case 'H':
return keyHome, b[3:]
case 'F':
return keyEnd, b[3:]
}
}
if !pasteActive && len(b) >= 6 && b[0] == keyEscape && b[1] == '[' && b[2] == '1' && b[3] == ';' && b[4] == '3' {
switch b[5] {
case 'C':
return keyAltRight, b[6:]
case 'D':
return keyAltLeft, b[6:]
}
}
if !pasteActive && len(b) >= 6 && bytes.Equal(b[:6], pasteStart) {
return keyPasteStart, b[6:]
}
if pasteActive && len(b) >= 6 && bytes.Equal(b[:6], pasteEnd) {
return keyPasteEnd, b[6:]
}
// If we get here then we have a key that we don't recognise, or a
// partial sequence. It's not clear how one should find the end of a
// sequence without knowing them all, but it seems that [a-zA-Z~] only
// appears at the end of a sequence.
for i, c := range b[0:] {
if c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z' || c == '~' {
return keyUnknown, b[i+1:]
}
}
return utf8.RuneError, b
}
// queue appends data to the end of t.outBuf
func (t *Terminal) queue(data []rune) {
t.outBuf = append(t.outBuf, []byte(string(data))...)
}
var eraseUnderCursor = []rune{' ', keyEscape, '[', 'D'}
var space = []rune{' '}
func isPrintable(key rune) bool {
isInSurrogateArea := key >= 0xd800 && key <= 0xdbff
return key >= 32 && !isInSurrogateArea
}
// moveCursorToPos appends data to t.outBuf which will move the cursor to the
// given, logical position in the text.
func (t *Terminal) moveCursorToPos(pos int) {
if !t.echo {
return
}
x := visualLength(t.prompt) + pos
y := x / t.termWidth
x = x % t.termWidth
up := 0
if y < t.cursorY {
up = t.cursorY - y
}
down := 0
if y > t.cursorY {
down = y - t.cursorY
}
left := 0
if x < t.cursorX {
left = t.cursorX - x
}
right := 0
if x > t.cursorX {
right = x - t.cursorX
}
t.cursorX = x
t.cursorY = y
t.move(up, down, left, right)
}
func (t *Terminal) move(up, down, left, right int) {
movement := make([]rune, 3*(up+down+left+right))
m := movement
for i := 0; i < up; i++ {
m[0] = keyEscape
m[1] = '['
m[2] = 'A'
m = m[3:]
}
for i := 0; i < down; i++ {
m[0] = keyEscape
m[1] = '['
m[2] = 'B'
m = m[3:]
}
for i := 0; i < left; i++ {
m[0] = keyEscape
m[1] = '['
m[2] = 'D'
m = m[3:]
}
for i := 0; i < right; i++ {
m[0] = keyEscape
m[1] = '['
m[2] = 'C'
m = m[3:]
}
t.queue(movement)
}
func (t *Terminal) clearLineToRight() {
op := []rune{keyEscape, '[', 'K'}
t.queue(op)
}
const maxLineLength = 4096
func (t *Terminal) setLine(newLine []rune, newPos int) {
if t.echo {
t.moveCursorToPos(0)
t.writeLine(newLine)
for i := len(newLine); i < len(t.line); i++ {
t.writeLine(space)
}
t.moveCursorToPos(newPos)
}
t.line = newLine
t.pos = newPos
}
func (t *Terminal) advanceCursor(places int) {
t.cursorX += places
t.cursorY += t.cursorX / t.termWidth
if t.cursorY > t.maxLine {
t.maxLine = t.cursorY
}
t.cursorX = t.cursorX % t.termWidth
if places > 0 && t.cursorX == 0 {
// Normally terminals will advance the current position
// when writing a character. But that doesn't happen
// for the last character in a line. However, when
// writing a character (except a new line) that causes
// a line wrap, the position will be advanced two
// places.
//
// So, if we are stopping at the end of a line, we
// need to write a newline so that our cursor can be
// advanced to the next line.
t.outBuf = append(t.outBuf, '\n')
}
}
func (t *Terminal) eraseNPreviousChars(n int) {
if n == 0 {
return
}
if t.pos < n {
n = t.pos
}
t.pos -= n
t.moveCursorToPos(t.pos)
copy(t.line[t.pos:], t.line[n+t.pos:])
t.line = t.line[:len(t.line)-n]
if t.echo {
t.writeLine(t.line[t.pos:])
for i := 0; i < n; i++ {
t.queue(space)
}
t.advanceCursor(n)
t.moveCursorToPos(t.pos)
}
}
// countToLeftWord returns then number of characters from the cursor to the
// start of the previous word.
func (t *Terminal) countToLeftWord() int {
if t.pos == 0 {
return 0
}
pos := t.pos - 1
for pos > 0 {
if t.line[pos] != ' ' {
break
}
pos--
}
for pos > 0 {
if t.line[pos] == ' ' {
pos++
break
}
pos--
}
return t.pos - pos
}
// countToRightWord returns then number of characters from the cursor to the
// start of the next word.
func (t *Terminal) countToRightWord() int {
pos := t.pos
for pos < len(t.line) {
if t.line[pos] == ' ' {
break
}
pos++
}
for pos < len(t.line) {
if t.line[pos] != ' ' {
break
}
pos++
}
return pos - t.pos
}
// visualLength returns the number of visible glyphs in s.
func visualLength(runes []rune) int {
inEscapeSeq := false
length := 0
for _, r := range runes {
switch {
case inEscapeSeq:
if (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') {
inEscapeSeq = false
}
case r == '\x1b':
inEscapeSeq = true
default:
length++
}
}
return length
}
// handleKey processes the given key and, optionally, returns a line of text
// that the user has entered.
func (t *Terminal) handleKey(key rune) (line string, ok bool) {
if t.pasteActive && key != keyEnter {
t.addKeyToLine(key)
return
}
switch key {
case keyBackspace:
if t.pos == 0 {
return
}
t.eraseNPreviousChars(1)
case keyAltLeft:
// move left by a word.
t.pos -= t.countToLeftWord()
t.moveCursorToPos(t.pos)
case keyAltRight:
// move right by a word.
t.pos += t.countToRightWord()
t.moveCursorToPos(t.pos)
case keyLeft:
if t.pos == 0 {
return
}
t.pos--
t.moveCursorToPos(t.pos)
case keyRight:
if t.pos == len(t.line) {
return
}
t.pos++
t.moveCursorToPos(t.pos)
case keyHome:
if t.pos == 0 {
return
}
t.pos = 0
t.moveCursorToPos(t.pos)
case keyEnd:
if t.pos == len(t.line) {
return
}
t.pos = len(t.line)
t.moveCursorToPos(t.pos)
case keyUp:
entry, ok := t.history.NthPreviousEntry(t.historyIndex + 1)
if !ok {
return "", false
}
if t.historyIndex == -1 {
t.historyPending = string(t.line)
}
t.historyIndex++
runes := []rune(entry)
t.setLine(runes, len(runes))
case keyDown:
switch t.historyIndex {
case -1:
return
case 0:
runes := []rune(t.historyPending)
t.setLine(runes, len(runes))
t.historyIndex--
default:
entry, ok := t.history.NthPreviousEntry(t.historyIndex - 1)
if ok {
t.historyIndex--
runes := []rune(entry)
t.setLine(runes, len(runes))
}
}
case keyEnter:
t.moveCursorToPos(len(t.line))
t.queue([]rune("\r\n"))
line = string(t.line)
ok = true
t.line = t.line[:0]
t.pos = 0
t.cursorX = 0
t.cursorY = 0
t.maxLine = 0
case keyDeleteWord:
// Delete zero or more spaces and then one or more characters.
t.eraseNPreviousChars(t.countToLeftWord())
case keyDeleteLine:
// Delete everything from the current cursor position to the
// end of line.
for i := t.pos; i < len(t.line); i++ {
t.queue(space)
t.advanceCursor(1)
}
t.line = t.line[:t.pos]
t.moveCursorToPos(t.pos)
case keyCtrlD:
// Erase the character under the current position.
// The EOF case when the line is empty is handled in
// readLine().
if t.pos < len(t.line) {
t.pos++
t.eraseNPreviousChars(1)
}
case keyCtrlU:
t.eraseNPreviousChars(t.pos)
case keyClearScreen:
// Erases the screen and moves the cursor to the home position.
t.queue([]rune("\x1b[2J\x1b[H"))
t.queue(t.prompt)
t.cursorX, t.cursorY = 0, 0
t.advanceCursor(visualLength(t.prompt))
t.setLine(t.line, t.pos)
default:
if t.AutoCompleteCallback != nil {
prefix := string(t.line[:t.pos])
suffix := string(t.line[t.pos:])
t.lock.Unlock()
newLine, newPos, completeOk := t.AutoCompleteCallback(prefix+suffix, len(prefix), key)
t.lock.Lock()
if completeOk {
t.setLine([]rune(newLine), utf8.RuneCount([]byte(newLine)[:newPos]))
return
}
}
if !isPrintable(key) {
return
}
if len(t.line) == maxLineLength {
return
}
t.addKeyToLine(key)
}
return
}
// addKeyToLine inserts the given key at the current position in the current
// line.
func (t *Terminal) addKeyToLine(key rune) {
if len(t.line) == cap(t.line) {
newLine := make([]rune, len(t.line), 2*(1+len(t.line)))
copy(newLine, t.line)
t.line = newLine
}
t.line = t.line[:len(t.line)+1]
copy(t.line[t.pos+1:], t.line[t.pos:])
t.line[t.pos] = key
if t.echo {
t.writeLine(t.line[t.pos:])
}
t.pos++
t.moveCursorToPos(t.pos)
}
func (t *Terminal) writeLine(line []rune) {
for len(line) != 0 {
remainingOnLine := t.termWidth - t.cursorX
todo := len(line)
if todo > remainingOnLine {
todo = remainingOnLine
}
t.queue(line[:todo])
t.advanceCursor(visualLength(line[:todo]))
line = line[todo:]
}
}
func (t *Terminal) Write(buf []byte) (n int, err error) {
t.lock.Lock()
defer t.lock.Unlock()
if t.cursorX == 0 && t.cursorY == 0 {
// This is the easy case: there's nothing on the screen that we
// have to move out of the way.
return t.c.Write(buf)
}
// We have a prompt and possibly user input on the screen. We
// have to clear it first.
t.move(0 /* up */, 0 /* down */, t.cursorX /* left */, 0 /* right */)
t.cursorX = 0
t.clearLineToRight()
for t.cursorY > 0 {
t.move(1 /* up */, 0, 0, 0)
t.cursorY--
t.clearLineToRight()
}
if _, err = t.c.Write(t.outBuf); err != nil {
return
}
t.outBuf = t.outBuf[:0]
if n, err = t.c.Write(buf); err != nil {
return
}
t.writeLine(t.prompt)
if t.echo {
t.writeLine(t.line)
}
t.moveCursorToPos(t.pos)
if _, err = t.c.Write(t.outBuf); err != nil {
return
}
t.outBuf = t.outBuf[:0]
return
}
// ReadPassword temporarily changes the prompt and reads a password, without
// echo, from the terminal.
func (t *Terminal) ReadPassword(prompt string) (line string, err error) {
t.lock.Lock()
defer t.lock.Unlock()
oldPrompt := t.prompt
t.prompt = []rune(prompt)
t.echo = false
line, err = t.readLine()
t.prompt = oldPrompt
t.echo = true
return
}
// ReadLine returns a line of input from the terminal.
func (t *Terminal) ReadLine() (line string, err error) {
t.lock.Lock()
defer t.lock.Unlock()
return t.readLine()
}
func (t *Terminal) readLine() (line string, err error) {
// t.lock must be held at this point
if t.cursorX == 0 && t.cursorY == 0 {
t.writeLine(t.prompt)
t.c.Write(t.outBuf)
t.outBuf = t.outBuf[:0]
}
lineIsPasted := t.pasteActive
for {
rest := t.remainder
lineOk := false
for !lineOk {
var key rune
key, rest = bytesToKey(rest, t.pasteActive)
if key == utf8.RuneError {
break
}
if !t.pasteActive {
if key == keyCtrlD {
if len(t.line) == 0 {
return "", io.EOF
}
}
if key == keyPasteStart {
t.pasteActive = true
if len(t.line) == 0 {
lineIsPasted = true
}
continue
}
} else if key == keyPasteEnd {
t.pasteActive = false
continue
}
if !t.pasteActive {
lineIsPasted = false
}
line, lineOk = t.handleKey(key)
}
if len(rest) > 0 {
n := copy(t.inBuf[:], rest)
t.remainder = t.inBuf[:n]
} else {
t.remainder = nil
}
t.c.Write(t.outBuf)
t.outBuf = t.outBuf[:0]
if lineOk {
if t.echo {
t.historyIndex = -1
t.history.Add(line)
}
if lineIsPasted {
err = ErrPasteIndicator
}
return
}
// t.remainder is a slice at the beginning of t.inBuf
// containing a partial key sequence
readBuf := t.inBuf[len(t.remainder):]
var n int
t.lock.Unlock()
n, err = t.c.Read(readBuf)
t.lock.Lock()
if err != nil {
return
}
t.remainder = t.inBuf[:n+len(t.remainder)]
}
panic("unreachable") // for Go 1.0.
}
// SetPrompt sets the prompt to be used when reading subsequent lines.
func (t *Terminal) SetPrompt(prompt string) {
t.lock.Lock()
defer t.lock.Unlock()
t.prompt = []rune(prompt)
}
func (t *Terminal) clearAndRepaintLinePlusNPrevious(numPrevLines int) {
// Move cursor to column zero at the start of the line.
t.move(t.cursorY, 0, t.cursorX, 0)
t.cursorX, t.cursorY = 0, 0
t.clearLineToRight()
for t.cursorY < numPrevLines {
// Move down a line
t.move(0, 1, 0, 0)
t.cursorY++
t.clearLineToRight()
}
// Move back to beginning.
t.move(t.cursorY, 0, 0, 0)
t.cursorX, t.cursorY = 0, 0
t.queue(t.prompt)
t.advanceCursor(visualLength(t.prompt))
t.writeLine(t.line)
t.moveCursorToPos(t.pos)
}
func (t *Terminal) SetSize(width, height int) error {
t.lock.Lock()
defer t.lock.Unlock()
if width == 0 {
width = 1
}
oldWidth := t.termWidth
t.termWidth, t.termHeight = width, height
switch {
case width == oldWidth:
// If the width didn't change then nothing else needs to be
// done.
return nil
case len(t.line) == 0 && t.cursorX == 0 && t.cursorY == 0:
// If there is nothing on current line and no prompt printed,
// just do nothing
return nil
case width < oldWidth:
// Some terminals (e.g. xterm) will truncate lines that were
// too long when shinking. Others, (e.g. gnome-terminal) will
// attempt to wrap them. For the former, repainting t.maxLine
// works great, but that behaviour goes badly wrong in the case
// of the latter because they have doubled every full line.
// We assume that we are working on a terminal that wraps lines
// and adjust the cursor position based on every previous line
// wrapping and turning into two. This causes the prompt on
// xterms to move upwards, which isn't great, but it avoids a
// huge mess with gnome-terminal.
if t.cursorX >= t.termWidth {
t.cursorX = t.termWidth - 1
}
t.cursorY *= 2
t.clearAndRepaintLinePlusNPrevious(t.maxLine * 2)
case width > oldWidth:
// If the terminal expands then our position calculations will
// be wrong in the future because we think the cursor is
// |t.pos| chars into the string, but there will be a gap at
// the end of any wrapped line.
//
// But the position will actually be correct until we move, so
// we can move back to the beginning and repaint everything.
t.clearAndRepaintLinePlusNPrevious(t.maxLine)
}
_, err := t.c.Write(t.outBuf)
t.outBuf = t.outBuf[:0]
return err
}
type pasteIndicatorError struct{}
func (pasteIndicatorError) Error() string {
return "terminal: ErrPasteIndicator not correctly handled"
}
// ErrPasteIndicator may be returned from ReadLine as the error, in addition
// to valid line data. It indicates that bracketed paste mode is enabled and
// that the returned line consists only of pasted data. Programs may wish to
// interpret pasted data more literally than typed data.
var ErrPasteIndicator = pasteIndicatorError{}
// SetBracketedPasteMode requests that the terminal bracket paste operations
// with markers. Not all terminals support this but, if it is supported, then
// enabling this mode will stop any autocomplete callback from running due to
// pastes. Additionally, any lines that are completely pasted will be returned
// from ReadLine with the error set to ErrPasteIndicator.
func (t *Terminal) SetBracketedPasteMode(on bool) {
if on {
io.WriteString(t.c, "\x1b[?2004h")
} else {
io.WriteString(t.c, "\x1b[?2004l")
}
}
// stRingBuffer is a ring buffer of strings.
type stRingBuffer struct {
// entries contains max elements.
entries []string
max int
// head contains the index of the element most recently added to the ring.
head int
// size contains the number of elements in the ring.
size int
}
func (s *stRingBuffer) Add(a string) {
if s.entries == nil {
const defaultNumEntries = 100
s.entries = make([]string, defaultNumEntries)
s.max = defaultNumEntries
}
s.head = (s.head + 1) % s.max
s.entries[s.head] = a
if s.size < s.max {
s.size++
}
}
// NthPreviousEntry returns the value passed to the nth previous call to Add.
// If n is zero then the immediately prior value is returned, if one, then the
// next most recent, and so on. If such an element doesn't exist then ok is
// false.
func (s *stRingBuffer) NthPreviousEntry(n int) (value string, ok bool) {
if n >= s.size {
return "", false
}
index := s.head - n
if index < 0 {
index += s.max
}
return s.entries[index], true
}

269
modules/crypto/ssh/terminal/terminal_test.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package terminal
import (
"io"
"testing"
)
type MockTerminal struct {
toSend []byte
bytesPerRead int
received []byte
}
func (c *MockTerminal) Read(data []byte) (n int, err error) {
n = len(data)
if n == 0 {
return
}
if n > len(c.toSend) {
n = len(c.toSend)
}
if n == 0 {
return 0, io.EOF
}
if c.bytesPerRead > 0 && n > c.bytesPerRead {
n = c.bytesPerRead
}
copy(data, c.toSend[:n])
c.toSend = c.toSend[n:]
return
}
func (c *MockTerminal) Write(data []byte) (n int, err error) {
c.received = append(c.received, data...)
return len(data), nil
}
func TestClose(t *testing.T) {
c := &MockTerminal{}
ss := NewTerminal(c, "> ")
line, err := ss.ReadLine()
if line != "" {
t.Errorf("Expected empty line but got: %s", line)
}
if err != io.EOF {
t.Errorf("Error should have been EOF but got: %s", err)
}
}
var keyPressTests = []struct {
in string
line string
err error
throwAwayLines int
}{
{
err: io.EOF,
},
{
in: "\r",
line: "",
},
{
in: "foo\r",
line: "foo",
},
{
in: "a\x1b[Cb\r", // right
line: "ab",
},
{
in: "a\x1b[Db\r", // left
line: "ba",
},
{
in: "a\177b\r", // backspace
line: "b",
},
{
in: "\x1b[A\r", // up
},
{
in: "\x1b[B\r", // down
},
{
in: "line\x1b[A\x1b[B\r", // up then down
line: "line",
},
{
in: "line1\rline2\x1b[A\r", // recall previous line.
line: "line1",
throwAwayLines: 1,
},
{
// recall two previous lines and append.
in: "line1\rline2\rline3\x1b[A\x1b[Axxx\r",
line: "line1xxx",
throwAwayLines: 2,
},
{
// Ctrl-A to move to beginning of line followed by ^K to kill
// line.
in: "a b \001\013\r",
line: "",
},
{
// Ctrl-A to move to beginning of line, Ctrl-E to move to end,
// finally ^K to kill nothing.
in: "a b \001\005\013\r",
line: "a b ",
},
{
in: "\027\r",
line: "",
},
{
in: "a\027\r",
line: "",
},
{
in: "a \027\r",
line: "",
},
{
in: "a b\027\r",
line: "a ",
},
{
in: "a b \027\r",
line: "a ",
},
{
in: "one two thr\x1b[D\027\r",
line: "one two r",
},
{
in: "\013\r",
line: "",
},
{
in: "a\013\r",
line: "a",
},
{
in: "ab\x1b[D\013\r",
line: "a",
},
{
in: "Ξεσκεπάζω\r",
line: "Ξεσκεπάζω",
},
{
in: "£\r\x1b[A\177\r", // non-ASCII char, enter, up, backspace.
line: "",
throwAwayLines: 1,
},
{
in: "£\r££\x1b[A\x1b[B\177\r", // non-ASCII char, enter, 2x non-ASCII, up, down, backspace, enter.
line: "£",
throwAwayLines: 1,
},
{
// Ctrl-D at the end of the line should be ignored.
in: "a\004\r",
line: "a",
},
{
// a, b, left, Ctrl-D should erase the b.
in: "ab\x1b[D\004\r",
line: "a",
},
{
// a, b, c, d, left, left, ^U should erase to the beginning of
// the line.
in: "abcd\x1b[D\x1b[D\025\r",
line: "cd",
},
{
// Bracketed paste mode: control sequences should be returned
// verbatim in paste mode.
in: "abc\x1b[200~de\177f\x1b[201~\177\r",
line: "abcde\177",
},
{
// Enter in bracketed paste mode should still work.
in: "abc\x1b[200~d\refg\x1b[201~h\r",
line: "efgh",
throwAwayLines: 1,
},
{
// Lines consisting entirely of pasted data should be indicated as such.
in: "\x1b[200~a\r",
line: "a",
err: ErrPasteIndicator,
},
}
func TestKeyPresses(t *testing.T) {
for i, test := range keyPressTests {
for j := 1; j < len(test.in); j++ {
c := &MockTerminal{
toSend: []byte(test.in),
bytesPerRead: j,
}
ss := NewTerminal(c, "> ")
for k := 0; k < test.throwAwayLines; k++ {
_, err := ss.ReadLine()
if err != nil {
t.Errorf("Throwaway line %d from test %d resulted in error: %s", k, i, err)
}
}
line, err := ss.ReadLine()
if line != test.line {
t.Errorf("Line resulting from test %d (%d bytes per read) was '%s', expected '%s'", i, j, line, test.line)
break
}
if err != test.err {
t.Errorf("Error resulting from test %d (%d bytes per read) was '%v', expected '%v'", i, j, err, test.err)
break
}
}
}
}
func TestPasswordNotSaved(t *testing.T) {
c := &MockTerminal{
toSend: []byte("password\r\x1b[A\r"),
bytesPerRead: 1,
}
ss := NewTerminal(c, "> ")
pw, _ := ss.ReadPassword("> ")
if pw != "password" {
t.Fatalf("failed to read password, got %s", pw)
}
line, _ := ss.ReadLine()
if len(line) > 0 {
t.Fatalf("password was saved in history")
}
}
var setSizeTests = []struct {
width, height int
}{
{40, 13},
{80, 24},
{132, 43},
}
func TestTerminalSetSize(t *testing.T) {
for _, setSize := range setSizeTests {
c := &MockTerminal{
toSend: []byte("password\r\x1b[A\r"),
bytesPerRead: 1,
}
ss := NewTerminal(c, "> ")
ss.SetSize(setSize.width, setSize.height)
pw, _ := ss.ReadPassword("Password: ")
if pw != "password" {
t.Fatalf("failed to read password, got %s", pw)
}
if string(c.received) != "Password: \r\n" {
t.Errorf("failed to set the temporary prompt expected %q, got %q", "Password: ", c.received)
}
}
}

128
modules/crypto/ssh/terminal/util.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build darwin dragonfly freebsd linux,!appengine netbsd openbsd
// Package terminal provides support functions for dealing with terminals, as
// commonly found on UNIX systems.
//
// Putting a terminal into raw mode is the most common requirement:
//
// oldState, err := terminal.MakeRaw(0)
// if err != nil {
// panic(err)
// }
// defer terminal.Restore(0, oldState)
package terminal // import "golang.org/x/crypto/ssh/terminal"
import (
"io"
"syscall"
"unsafe"
)
// State contains the state of a terminal.
type State struct {
termios syscall.Termios
}
// IsTerminal returns true if the given file descriptor is a terminal.
func IsTerminal(fd int) bool {
var termios syscall.Termios
_, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlReadTermios, uintptr(unsafe.Pointer(&termios)), 0, 0, 0)
return err == 0
}
// MakeRaw put the terminal connected to the given file descriptor into raw
// mode and returns the previous state of the terminal so that it can be
// restored.
func MakeRaw(fd int) (*State, error) {
var oldState State
if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlReadTermios, uintptr(unsafe.Pointer(&oldState.termios)), 0, 0, 0); err != 0 {
return nil, err
}
newState := oldState.termios
newState.Iflag &^= syscall.ISTRIP | syscall.INLCR | syscall.ICRNL | syscall.IGNCR | syscall.IXON | syscall.IXOFF
newState.Lflag &^= syscall.ECHO | syscall.ICANON | syscall.ISIG
if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlWriteTermios, uintptr(unsafe.Pointer(&newState)), 0, 0, 0); err != 0 {
return nil, err
}
return &oldState, nil
}
// GetState returns the current state of a terminal which may be useful to
// restore the terminal after a signal.
func GetState(fd int) (*State, error) {
var oldState State
if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlReadTermios, uintptr(unsafe.Pointer(&oldState.termios)), 0, 0, 0); err != 0 {
return nil, err
}
return &oldState, nil
}
// Restore restores the terminal connected to the given file descriptor to a
// previous state.
func Restore(fd int, state *State) error {
_, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlWriteTermios, uintptr(unsafe.Pointer(&state.termios)), 0, 0, 0)
return err
}
// GetSize returns the dimensions of the given terminal.
func GetSize(fd int) (width, height int, err error) {
var dimensions [4]uint16
if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), uintptr(syscall.TIOCGWINSZ), uintptr(unsafe.Pointer(&dimensions)), 0, 0, 0); err != 0 {
return -1, -1, err
}
return int(dimensions[1]), int(dimensions[0]), nil
}
// ReadPassword reads a line of input from a terminal without local echo. This
// is commonly used for inputting passwords and other sensitive data. The slice
// returned does not include the \n.
func ReadPassword(fd int) ([]byte, error) {
var oldState syscall.Termios
if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlReadTermios, uintptr(unsafe.Pointer(&oldState)), 0, 0, 0); err != 0 {
return nil, err
}
newState := oldState
newState.Lflag &^= syscall.ECHO
newState.Lflag |= syscall.ICANON | syscall.ISIG
newState.Iflag |= syscall.ICRNL
if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlWriteTermios, uintptr(unsafe.Pointer(&newState)), 0, 0, 0); err != 0 {
return nil, err
}
defer func() {
syscall.Syscall6(syscall.SYS_IOCTL, uintptr(fd), ioctlWriteTermios, uintptr(unsafe.Pointer(&oldState)), 0, 0, 0)
}()
var buf [16]byte
var ret []byte
for {
n, err := syscall.Read(fd, buf[:])
if err != nil {
return nil, err
}
if n == 0 {
if len(ret) == 0 {
return nil, io.EOF
}
break
}
if buf[n-1] == '\n' {
n--
}
ret = append(ret, buf[:n]...)
if n < len(buf) {
break
}
}
return ret, nil
}

12
modules/crypto/ssh/terminal/util_bsd.go
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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build darwin dragonfly freebsd netbsd openbsd
package terminal
import "syscall"
const ioctlReadTermios = syscall.TIOCGETA
const ioctlWriteTermios = syscall.TIOCSETA

11
modules/crypto/ssh/terminal/util_linux.go
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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package terminal
// These constants are declared here, rather than importing
// them from the syscall package as some syscall packages, even
// on linux, for example gccgo, do not declare them.
const ioctlReadTermios = 0x5401 // syscall.TCGETS
const ioctlWriteTermios = 0x5402 // syscall.TCSETS

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modules/crypto/ssh/terminal/util_windows.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build windows
// Package terminal provides support functions for dealing with terminals, as
// commonly found on UNIX systems.
//
// Putting a terminal into raw mode is the most common requirement:
//
// oldState, err := terminal.MakeRaw(0)
// if err != nil {
// panic(err)
// }
// defer terminal.Restore(0, oldState)
package terminal
import (
"io"
"syscall"
"unsafe"
)
const (
enableLineInput = 2
enableEchoInput = 4
enableProcessedInput = 1
enableWindowInput = 8
enableMouseInput = 16
enableInsertMode = 32
enableQuickEditMode = 64
enableExtendedFlags = 128
enableAutoPosition = 256
enableProcessedOutput = 1
enableWrapAtEolOutput = 2
)
var kernel32 = syscall.NewLazyDLL("kernel32.dll")
var (
procGetConsoleMode = kernel32.NewProc("GetConsoleMode")
procSetConsoleMode = kernel32.NewProc("SetConsoleMode")
procGetConsoleScreenBufferInfo = kernel32.NewProc("GetConsoleScreenBufferInfo")
)
type (
short int16
word uint16
coord struct {
x short
y short
}
smallRect struct {
left short
top short
right short
bottom short
}
consoleScreenBufferInfo struct {
size coord
cursorPosition coord
attributes word
window smallRect
maximumWindowSize coord
}
)
type State struct {
mode uint32
}
// IsTerminal returns true if the given file descriptor is a terminal.
func IsTerminal(fd int) bool {
var st uint32
r, _, e := syscall.Syscall(procGetConsoleMode.Addr(), 2, uintptr(fd), uintptr(unsafe.Pointer(&st)), 0)
return r != 0 && e == 0
}
// MakeRaw put the terminal connected to the given file descriptor into raw
// mode and returns the previous state of the terminal so that it can be
// restored.
func MakeRaw(fd int) (*State, error) {
var st uint32
_, _, e := syscall.Syscall(procGetConsoleMode.Addr(), 2, uintptr(fd), uintptr(unsafe.Pointer(&st)), 0)
if e != 0 {
return nil, error(e)
}
st &^= (enableEchoInput | enableProcessedInput | enableLineInput | enableProcessedOutput)
_, _, e = syscall.Syscall(procSetConsoleMode.Addr(), 2, uintptr(fd), uintptr(st), 0)
if e != 0 {
return nil, error(e)
}
return &State{st}, nil
}
// GetState returns the current state of a terminal which may be useful to
// restore the terminal after a signal.
func GetState(fd int) (*State, error) {
var st uint32
_, _, e := syscall.Syscall(procGetConsoleMode.Addr(), 2, uintptr(fd), uintptr(unsafe.Pointer(&st)), 0)
if e != 0 {
return nil, error(e)
}
return &State{st}, nil
}
// Restore restores the terminal connected to the given file descriptor to a
// previous state.
func Restore(fd int, state *State) error {
_, _, err := syscall.Syscall(procSetConsoleMode.Addr(), 2, uintptr(fd), uintptr(state.mode), 0)
return err
}
// GetSize returns the dimensions of the given terminal.
func GetSize(fd int) (width, height int, err error) {
var info consoleScreenBufferInfo
_, _, e := syscall.Syscall(procGetConsoleScreenBufferInfo.Addr(), 2, uintptr(fd), uintptr(unsafe.Pointer(&info)), 0)
if e != 0 {
return 0, 0, error(e)
}
return int(info.size.x), int(info.size.y), nil
}
// ReadPassword reads a line of input from a terminal without local echo. This
// is commonly used for inputting passwords and other sensitive data. The slice
// returned does not include the \n.
func ReadPassword(fd int) ([]byte, error) {
var st uint32
_, _, e := syscall.Syscall(procGetConsoleMode.Addr(), 2, uintptr(fd), uintptr(unsafe.Pointer(&st)), 0)
if e != 0 {
return nil, error(e)
}
old := st
st &^= (enableEchoInput)
st |= (enableProcessedInput | enableLineInput | enableProcessedOutput)
_, _, e = syscall.Syscall(procSetConsoleMode.Addr(), 2, uintptr(fd), uintptr(st), 0)
if e != 0 {
return nil, error(e)
}
defer func() {
syscall.Syscall(procSetConsoleMode.Addr(), 2, uintptr(fd), uintptr(old), 0)
}()
var buf [16]byte
var ret []byte
for {
n, err := syscall.Read(syscall.Handle(fd), buf[:])
if err != nil {
return nil, err
}
if n == 0 {
if len(ret) == 0 {
return nil, io.EOF
}
break
}
if buf[n-1] == '\n' {
n--
}
if n > 0 && buf[n-1] == '\r' {
n--
}
ret = append(ret, buf[:n]...)
if n < len(buf) {
break
}
}
return ret, nil
}

59
modules/crypto/ssh/test/agent_unix_test.go
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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build darwin dragonfly freebsd linux netbsd openbsd
package test
import (
"bytes"
"testing"
"golang.org/x/crypto/ssh"
"golang.org/x/crypto/ssh/agent"
)
func TestAgentForward(t *testing.T) {
server := newServer(t)
defer server.Shutdown()
conn := server.Dial(clientConfig())
defer conn.Close()
keyring := agent.NewKeyring()
if err := keyring.Add(agent.AddedKey{PrivateKey: testPrivateKeys["dsa"]}); err != nil {
t.Fatalf("Error adding key: %s", err)
}
if err := keyring.Add(agent.AddedKey{
PrivateKey: testPrivateKeys["dsa"],
ConfirmBeforeUse: true,
LifetimeSecs: 3600,
}); err != nil {
t.Fatalf("Error adding key with constraints: %s", err)
}
pub := testPublicKeys["dsa"]
sess, err := conn.NewSession()
if err != nil {
t.Fatalf("NewSession: %v", err)
}
if err := agent.RequestAgentForwarding(sess); err != nil {
t.Fatalf("RequestAgentForwarding: %v", err)
}
if err := agent.ForwardToAgent(conn, keyring); err != nil {
t.Fatalf("SetupForwardKeyring: %v", err)
}
out, err := sess.CombinedOutput("ssh-add -L")
if err != nil {
t.Fatalf("running ssh-add: %v, out %s", err, out)
}
key, _, _, _, err := ssh.ParseAuthorizedKey(out)
if err != nil {
t.Fatalf("ParseAuthorizedKey(%q): %v", out, err)
}
if !bytes.Equal(key.Marshal(), pub.Marshal()) {
t.Fatalf("got key %s, want %s", ssh.MarshalAuthorizedKey(key), ssh.MarshalAuthorizedKey(pub))
}
}

47
modules/crypto/ssh/test/cert_test.go
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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build darwin dragonfly freebsd linux netbsd openbsd
package test
import (
"crypto/rand"
"testing"
"golang.org/x/crypto/ssh"
)
func TestCertLogin(t *testing.T) {
s := newServer(t)
defer s.Shutdown()
// Use a key different from the default.
clientKey := testSigners["dsa"]
caAuthKey := testSigners["ecdsa"]
cert := &ssh.Certificate{
Key: clientKey.PublicKey(),
ValidPrincipals: []string{username()},
CertType: ssh.UserCert,
ValidBefore: ssh.CertTimeInfinity,
}
if err := cert.SignCert(rand.Reader, caAuthKey); err != nil {
t.Fatalf("SetSignature: %v", err)
}
certSigner, err := ssh.NewCertSigner(cert, clientKey)
if err != nil {
t.Fatalf("NewCertSigner: %v", err)
}
conf := &ssh.ClientConfig{
User: username(),
}
conf.Auth = append(conf.Auth, ssh.PublicKeys(certSigner))
client, err := s.TryDial(conf)
if err != nil {
t.Fatalf("TryDial: %v", err)
}
client.Close()
}

7
modules/crypto/ssh/test/doc.go
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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// This package contains integration tests for the
// golang.org/x/crypto/ssh package.
package test // import "golang.org/x/crypto/ssh/test"

160
modules/crypto/ssh/test/forward_unix_test.go
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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build darwin dragonfly freebsd linux netbsd openbsd
package test
import (
"bytes"
"io"
"io/ioutil"
"math/rand"
"net"
"testing"
"time"
)
func TestPortForward(t *testing.T) {
server := newServer(t)
defer server.Shutdown()
conn := server.Dial(clientConfig())
defer conn.Close()
sshListener, err := conn.Listen("tcp", "localhost:0")
if err != nil {
t.Fatal(err)
}
go func() {
sshConn, err := sshListener.Accept()
if err != nil {
t.Fatalf("listen.Accept failed: %v", err)
}
_, err = io.Copy(sshConn, sshConn)
if err != nil && err != io.EOF {
t.Fatalf("ssh client copy: %v", err)
}
sshConn.Close()
}()
forwardedAddr := sshListener.Addr().String()
tcpConn, err := net.Dial("tcp", forwardedAddr)
if err != nil {
t.Fatalf("TCP dial failed: %v", err)
}
readChan := make(chan []byte)
go func() {
data, _ := ioutil.ReadAll(tcpConn)
readChan <- data
}()
// Invent some data.
data := make([]byte, 100*1000)
for i := range data {
data[i] = byte(i % 255)
}
var sent []byte
for len(sent) < 1000*1000 {
// Send random sized chunks
m := rand.Intn(len(data))
n, err := tcpConn.Write(data[:m])
if err != nil {
break
}
sent = append(sent, data[:n]...)
}
if err := tcpConn.(*net.TCPConn).CloseWrite(); err != nil {
t.Errorf("tcpConn.CloseWrite: %v", err)
}
read := <-readChan
if len(sent) != len(read) {
t.Fatalf("got %d bytes, want %d", len(read), len(sent))
}
if bytes.Compare(sent, read) != 0 {
t.Fatalf("read back data does not match")
}
if err := sshListener.Close(); err != nil {
t.Fatalf("sshListener.Close: %v", err)
}
// Check that the forward disappeared.
tcpConn, err = net.Dial("tcp", forwardedAddr)
if err == nil {
tcpConn.Close()
t.Errorf("still listening to %s after closing", forwardedAddr)
}
}
func TestAcceptClose(t *testing.T) {
server := newServer(t)
defer server.Shutdown()
conn := server.Dial(clientConfig())
sshListener, err := conn.Listen("tcp", "localhost:0")
if err != nil {
t.Fatal(err)
}
quit := make(chan error, 1)
go func() {
for {
c, err := sshListener.Accept()
if err != nil {
quit <- err
break
}
c.Close()
}
}()
sshListener.Close()
select {
case <-time.After(1 * time.Second):
t.Errorf("timeout: listener did not close.")
case err := <-quit:
t.Logf("quit as expected (error %v)", err)
}
}
// Check that listeners exit if the underlying client transport dies.
func TestPortForwardConnectionClose(t *testing.T) {
server := newServer(t)
defer server.Shutdown()
conn := server.Dial(clientConfig())
sshListener, err := conn.Listen("tcp", "localhost:0")
if err != nil {
t.Fatal(err)
}
quit := make(chan error, 1)
go func() {
for {
c, err := sshListener.Accept()
if err != nil {
quit <- err
break
}
c.Close()
}
}()
// It would be even nicer if we closed the server side, but it
// is more involved as the fd for that side is dup()ed.
server.clientConn.Close()
select {
case <-time.After(1 * time.Second):
t.Errorf("timeout: listener did not close.")
case err := <-quit:
t.Logf("quit as expected (error %v)", err)
}
}

340
modules/crypto/ssh/test/session_test.go
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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build !windows
package test
// Session functional tests.
import (
"bytes"
"errors"
"io"
"strings"
"testing"
"golang.org/x/crypto/ssh"
)
func TestRunCommandSuccess(t *testing.T) {
server := newServer(t)
defer server.Shutdown()
conn := server.Dial(clientConfig())
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatalf("session failed: %v", err)
}
defer session.Close()
err = session.Run("true")
if err != nil {
t.Fatalf("session failed: %v", err)
}
}
func TestHostKeyCheck(t *testing.T) {
server := newServer(t)
defer server.Shutdown()
conf := clientConfig()
hostDB := hostKeyDB()
conf.HostKeyCallback = hostDB.Check
// change the keys.
hostDB.keys[ssh.KeyAlgoRSA][25]++
hostDB.keys[ssh.KeyAlgoDSA][25]++
hostDB.keys[ssh.KeyAlgoECDSA256][25]++
conn, err := server.TryDial(conf)
if err == nil {
conn.Close()
t.Fatalf("dial should have failed.")
} else if !strings.Contains(err.Error(), "host key mismatch") {
t.Fatalf("'host key mismatch' not found in %v", err)
}
}
func TestRunCommandStdin(t *testing.T) {
server := newServer(t)
defer server.Shutdown()
conn := server.Dial(clientConfig())
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatalf("session failed: %v", err)
}
defer session.Close()
r, w := io.Pipe()
defer r.Close()
defer w.Close()
session.Stdin = r
err = session.Run("true")
if err != nil {
t.Fatalf("session failed: %v", err)
}
}
func TestRunCommandStdinError(t *testing.T) {
server := newServer(t)
defer server.Shutdown()
conn := server.Dial(clientConfig())
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatalf("session failed: %v", err)
}
defer session.Close()
r, w := io.Pipe()
defer r.Close()
session.Stdin = r
pipeErr := errors.New("closing write end of pipe")
w.CloseWithError(pipeErr)
err = session.Run("true")
if err != pipeErr {
t.Fatalf("expected %v, found %v", pipeErr, err)
}
}
func TestRunCommandFailed(t *testing.T) {
server := newServer(t)
defer server.Shutdown()
conn := server.Dial(clientConfig())
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatalf("session failed: %v", err)
}
defer session.Close()
err = session.Run(`bash -c "kill -9 $$"`)
if err == nil {
t.Fatalf("session succeeded: %v", err)
}
}
func TestRunCommandWeClosed(t *testing.T) {
server := newServer(t)
defer server.Shutdown()
conn := server.Dial(clientConfig())
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatalf("session failed: %v", err)
}
err = session.Shell()
if err != nil {
t.Fatalf("shell failed: %v", err)
}
err = session.Close()
if err != nil {
t.Fatalf("shell failed: %v", err)
}
}
func TestFuncLargeRead(t *testing.T) {
server := newServer(t)
defer server.Shutdown()
conn := server.Dial(clientConfig())
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatalf("unable to create new session: %s", err)
}
stdout, err := session.StdoutPipe()
if err != nil {
t.Fatalf("unable to acquire stdout pipe: %s", err)
}
err = session.Start("dd if=/dev/urandom bs=2048 count=1024")
if err != nil {
t.Fatalf("unable to execute remote command: %s", err)
}
buf := new(bytes.Buffer)
n, err := io.Copy(buf, stdout)
if err != nil {
t.Fatalf("error reading from remote stdout: %s", err)
}
if n != 2048*1024 {
t.Fatalf("Expected %d bytes but read only %d from remote command", 2048, n)
}
}
func TestKeyChange(t *testing.T) {
server := newServer(t)
defer server.Shutdown()
conf := clientConfig()
hostDB := hostKeyDB()
conf.HostKeyCallback = hostDB.Check
conf.RekeyThreshold = 1024
conn := server.Dial(conf)
defer conn.Close()
for i := 0; i < 4; i++ {
session, err := conn.NewSession()
if err != nil {
t.Fatalf("unable to create new session: %s", err)
}
stdout, err := session.StdoutPipe()
if err != nil {
t.Fatalf("unable to acquire stdout pipe: %s", err)
}
err = session.Start("dd if=/dev/urandom bs=1024 count=1")
if err != nil {
t.Fatalf("unable to execute remote command: %s", err)
}
buf := new(bytes.Buffer)
n, err := io.Copy(buf, stdout)
if err != nil {
t.Fatalf("error reading from remote stdout: %s", err)
}
want := int64(1024)
if n != want {
t.Fatalf("Expected %d bytes but read only %d from remote command", want, n)
}
}
if changes := hostDB.checkCount; changes < 4 {
t.Errorf("got %d key changes, want 4", changes)
}
}
func TestInvalidTerminalMode(t *testing.T) {
server := newServer(t)
defer server.Shutdown()
conn := server.Dial(clientConfig())
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatalf("session failed: %v", err)
}
defer session.Close()
if err = session.RequestPty("vt100", 80, 40, ssh.TerminalModes{255: 1984}); err == nil {
t.Fatalf("req-pty failed: successful request with invalid mode")
}
}
func TestValidTerminalMode(t *testing.T) {
server := newServer(t)
defer server.Shutdown()
conn := server.Dial(clientConfig())
defer conn.Close()
session, err := conn.NewSession()
if err != nil {
t.Fatalf("session failed: %v", err)
}
defer session.Close()
stdout, err := session.StdoutPipe()
if err != nil {
t.Fatalf("unable to acquire stdout pipe: %s", err)
}
stdin, err := session.StdinPipe()
if err != nil {
t.Fatalf("unable to acquire stdin pipe: %s", err)
}
tm := ssh.TerminalModes{ssh.ECHO: 0}
if err = session.RequestPty("xterm", 80, 40, tm); err != nil {
t.Fatalf("req-pty failed: %s", err)
}
err = session.Shell()
if err != nil {
t.Fatalf("session failed: %s", err)
}
stdin.Write([]byte("stty -a && exit\n"))
var buf bytes.Buffer
if _, err := io.Copy(&buf, stdout); err != nil {
t.Fatalf("reading failed: %s", err)
}
if sttyOutput := buf.String(); !strings.Contains(sttyOutput, "-echo ") {
t.Fatalf("terminal mode failure: expected -echo in stty output, got %s", sttyOutput)
}
}
func TestCiphers(t *testing.T) {
var config ssh.Config
config.SetDefaults()
cipherOrder := config.Ciphers
// This cipher will not be tested when commented out in cipher.go it will
// fallback to the next available as per line 292.
cipherOrder = append(cipherOrder, "aes128-cbc")
for _, ciph := range cipherOrder {
server := newServer(t)
defer server.Shutdown()
conf := clientConfig()
conf.Ciphers = []string{ciph}
// Don't fail if sshd doesnt have the cipher.
conf.Ciphers = append(conf.Ciphers, cipherOrder...)
conn, err := server.TryDial(conf)
if err == nil {
conn.Close()
} else {
t.Fatalf("failed for cipher %q", ciph)
}
}
}
func TestMACs(t *testing.T) {
var config ssh.Config
config.SetDefaults()
macOrder := config.MACs
for _, mac := range macOrder {
server := newServer(t)
defer server.Shutdown()
conf := clientConfig()
conf.MACs = []string{mac}
// Don't fail if sshd doesnt have the MAC.
conf.MACs = append(conf.MACs, macOrder...)
if conn, err := server.TryDial(conf); err == nil {
conn.Close()
} else {
t.Fatalf("failed for MAC %q", mac)
}
}
}
func TestKeyExchanges(t *testing.T) {
var config ssh.Config
config.SetDefaults()
kexOrder := config.KeyExchanges
for _, kex := range kexOrder {
server := newServer(t)
defer server.Shutdown()
conf := clientConfig()
// Don't fail if sshd doesnt have the kex.
conf.KeyExchanges = append([]string{kex}, kexOrder...)
conn, err := server.TryDial(conf)
if err == nil {
conn.Close()
} else {
t.Errorf("failed for kex %q", kex)
}
}
}

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modules/crypto/ssh/test/tcpip_test.go
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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build !windows
package test
// direct-tcpip functional tests
import (
"io"
"net"
"testing"
)
func TestDial(t *testing.T) {
server := newServer(t)
defer server.Shutdown()
sshConn := server.Dial(clientConfig())
defer sshConn.Close()
l, err := net.Listen("tcp", "127.0.0.1:0")
if err != nil {
t.Fatalf("Listen: %v", err)
}
defer l.Close()
go func() {
for {
c, err := l.Accept()
if err != nil {
break
}
io.WriteString(c, c.RemoteAddr().String())
c.Close()
}
}()
conn, err := sshConn.Dial("tcp", l.Addr().String())
if err != nil {
t.Fatalf("Dial: %v", err)
}
defer conn.Close()
}

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modules/crypto/ssh/test/test_unix_test.go
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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build darwin dragonfly freebsd linux netbsd openbsd plan9
package test
// functional test harness for unix.
import (
"bytes"
"fmt"
"io/ioutil"
"log"
"net"
"os"
"os/exec"
"os/user"
"path/filepath"
"testing"
"text/template"
"golang.org/x/crypto/ssh"
"golang.org/x/crypto/ssh/testdata"
)
const sshd_config = `
Protocol 2
HostKey {{.Dir}}/id_rsa
HostKey {{.Dir}}/id_dsa
HostKey {{.Dir}}/id_ecdsa
Pidfile {{.Dir}}/sshd.pid
#UsePrivilegeSeparation no
KeyRegenerationInterval 3600
ServerKeyBits 768
SyslogFacility AUTH
LogLevel DEBUG2
LoginGraceTime 120
PermitRootLogin no
StrictModes no
RSAAuthentication yes
PubkeyAuthentication yes
AuthorizedKeysFile {{.Dir}}/id_user.pub
TrustedUserCAKeys {{.Dir}}/id_ecdsa.pub
IgnoreRhosts yes
RhostsRSAAuthentication no
HostbasedAuthentication no
`
var configTmpl = template.Must(template.New("").Parse(sshd_config))
type server struct {
t *testing.T
cleanup func() // executed during Shutdown
configfile string
cmd *exec.Cmd
output bytes.Buffer // holds stderr from sshd process
// Client half of the network connection.
clientConn net.Conn
}
func username() string {
var username string
if user, err := user.Current(); err == nil {
username = user.Username
} else {
// user.Current() currently requires cgo. If an error is
// returned attempt to get the username from the environment.
log.Printf("user.Current: %v; falling back on $USER", err)
username = os.Getenv("USER")
}
if username == "" {
panic("Unable to get username")
}
return username
}
type storedHostKey struct {
// keys map from an algorithm string to binary key data.
keys map[string][]byte
// checkCount counts the Check calls. Used for testing
// rekeying.
checkCount int
}
func (k *storedHostKey) Add(key ssh.PublicKey) {
if k.keys == nil {
k.keys = map[string][]byte{}
}
k.keys[key.Type()] = key.Marshal()
}
func (k *storedHostKey) Check(addr string, remote net.Addr, key ssh.PublicKey) error {
k.checkCount++
algo := key.Type()
if k.keys == nil || bytes.Compare(key.Marshal(), k.keys[algo]) != 0 {
return fmt.Errorf("host key mismatch. Got %q, want %q", key, k.keys[algo])
}
return nil
}
func hostKeyDB() *storedHostKey {
keyChecker := &storedHostKey{}
keyChecker.Add(testPublicKeys["ecdsa"])
keyChecker.Add(testPublicKeys["rsa"])
keyChecker.Add(testPublicKeys["dsa"])
return keyChecker
}
func clientConfig() *ssh.ClientConfig {
config := &ssh.ClientConfig{
User: username(),
Auth: []ssh.AuthMethod{
ssh.PublicKeys(testSigners["user"]),
},
HostKeyCallback: hostKeyDB().Check,
}
return config
}
// unixConnection creates two halves of a connected net.UnixConn. It
// is used for connecting the Go SSH client with sshd without opening
// ports.
func unixConnection() (*net.UnixConn, *net.UnixConn, error) {
dir, err := ioutil.TempDir("", "unixConnection")
if err != nil {
return nil, nil, err
}
defer os.Remove(dir)
addr := filepath.Join(dir, "ssh")
listener, err := net.Listen("unix", addr)
if err != nil {
return nil, nil, err
}
defer listener.Close()
c1, err := net.Dial("unix", addr)
if err != nil {
return nil, nil, err
}
c2, err := listener.Accept()
if err != nil {
c1.Close()
return nil, nil, err
}
return c1.(*net.UnixConn), c2.(*net.UnixConn), nil
}
func (s *server) TryDial(config *ssh.ClientConfig) (*ssh.Client, error) {
sshd, err := exec.LookPath("sshd")
if err != nil {
s.t.Skipf("skipping test: %v", err)
}
c1, c2, err := unixConnection()
if err != nil {
s.t.Fatalf("unixConnection: %v", err)
}
s.cmd = exec.Command(sshd, "-f", s.configfile, "-i", "-e")
f, err := c2.File()
if err != nil {
s.t.Fatalf("UnixConn.File: %v", err)
}
defer f.Close()
s.cmd.Stdin = f
s.cmd.Stdout = f
s.cmd.Stderr = &s.output
if err := s.cmd.Start(); err != nil {
s.t.Fail()
s.Shutdown()
s.t.Fatalf("s.cmd.Start: %v", err)
}
s.clientConn = c1
conn, chans, reqs, err := ssh.NewClientConn(c1, "", config)
if err != nil {
return nil, err
}
return ssh.NewClient(conn, chans, reqs), nil
}
func (s *server) Dial(config *ssh.ClientConfig) *ssh.Client {
conn, err := s.TryDial(config)
if err != nil {
s.t.Fail()
s.Shutdown()
s.t.Fatalf("ssh.Client: %v", err)
}
return conn
}
func (s *server) Shutdown() {
if s.cmd != nil && s.cmd.Process != nil {
// Don't check for errors; if it fails it's most
// likely "os: process already finished", and we don't
// care about that. Use os.Interrupt, so child
// processes are killed too.
s.cmd.Process.Signal(os.Interrupt)
s.cmd.Wait()
}
if s.t.Failed() {
// log any output from sshd process
s.t.Logf("sshd: %s", s.output.String())
}
s.cleanup()
}
func writeFile(path string, contents []byte) {
f, err := os.OpenFile(path, os.O_WRONLY|os.O_TRUNC|os.O_CREATE, 0600)
if err != nil {
panic(err)
}
defer f.Close()
if _, err := f.Write(contents); err != nil {
panic(err)
}
}
// newServer returns a new mock ssh server.
func newServer(t *testing.T) *server {
if testing.Short() {
t.Skip("skipping test due to -short")
}
dir, err := ioutil.TempDir("", "sshtest")
if err != nil {
t.Fatal(err)
}
f, err := os.Create(filepath.Join(dir, "sshd_config"))
if err != nil {
t.Fatal(err)
}
err = configTmpl.Execute(f, map[string]string{
"Dir": dir,
})
if err != nil {
t.Fatal(err)
}
f.Close()
for k, v := range testdata.PEMBytes {
filename := "id_" + k
writeFile(filepath.Join(dir, filename), v)
writeFile(filepath.Join(dir, filename+".pub"), ssh.MarshalAuthorizedKey(testPublicKeys[k]))
}
return &server{
t: t,
configfile: f.Name(),
cleanup: func() {
if err := os.RemoveAll(dir); err != nil {
t.Error(err)
}
},
}
}

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modules/crypto/ssh/test/testdata_test.go
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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// IMPLEMENTOR NOTE: To avoid a package loop, this file is in three places:
// ssh/, ssh/agent, and ssh/test/. It should be kept in sync across all three
// instances.
package test
import (
"crypto/rand"
"fmt"
"golang.org/x/crypto/ssh"
"golang.org/x/crypto/ssh/testdata"
)
var (
testPrivateKeys map[string]interface{}
testSigners map[string]ssh.Signer
testPublicKeys map[string]ssh.PublicKey
)
func init() {
var err error
n := len(testdata.PEMBytes)
testPrivateKeys = make(map[string]interface{}, n)
testSigners = make(map[string]ssh.Signer, n)
testPublicKeys = make(map[string]ssh.PublicKey, n)
for t, k := range testdata.PEMBytes {
testPrivateKeys[t], err = ssh.ParseRawPrivateKey(k)
if err != nil {
panic(fmt.Sprintf("Unable to parse test key %s: %v", t, err))
}
testSigners[t], err = ssh.NewSignerFromKey(testPrivateKeys[t])
if err != nil {
panic(fmt.Sprintf("Unable to create signer for test key %s: %v", t, err))
}
testPublicKeys[t] = testSigners[t].PublicKey()
}
// Create a cert and sign it for use in tests.
testCert := &ssh.Certificate{
Nonce: []byte{}, // To pass reflect.DeepEqual after marshal & parse, this must be non-nil
ValidPrincipals: []string{"gopher1", "gopher2"}, // increases test coverage
ValidAfter: 0, // unix epoch
ValidBefore: ssh.CertTimeInfinity, // The end of currently representable time.
Reserved: []byte{}, // To pass reflect.DeepEqual after marshal & parse, this must be non-nil
Key: testPublicKeys["ecdsa"],
SignatureKey: testPublicKeys["rsa"],
Permissions: ssh.Permissions{
CriticalOptions: map[string]string{},
Extensions: map[string]string{},
},
}
testCert.SignCert(rand.Reader, testSigners["rsa"])
testPrivateKeys["cert"] = testPrivateKeys["ecdsa"]
testSigners["cert"], err = ssh.NewCertSigner(testCert, testSigners["ecdsa"])
if err != nil {
panic(fmt.Sprintf("Unable to create certificate signer: %v", err))
}
}

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modules/crypto/ssh/testdata/doc.go vendored
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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// This package contains test data shared between the various subpackages of
// the golang.org/x/crypto/ssh package. Under no circumstance should
// this data be used for production code.
package testdata // import "golang.org/x/crypto/ssh/testdata"

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modules/crypto/ssh/testdata/keys.go vendored
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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package testdata
var PEMBytes = map[string][]byte{
"dsa": []byte(`-----BEGIN DSA PRIVATE KEY-----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-----END DSA PRIVATE KEY-----
`),
"ecdsa": []byte(`-----BEGIN EC PRIVATE KEY-----
MHcCAQEEINGWx0zo6fhJ/0EAfrPzVFyFC9s18lBt3cRoEDhS3ARooAoGCCqGSM49
AwEHoUQDQgAEi9Hdw6KvZcWxfg2IDhA7UkpDtzzt6ZqJXSsFdLd+Kx4S3Sx4cVO+
6/ZOXRnPmNAlLUqjShUsUBBngG0u2fqEqA==
-----END EC PRIVATE KEY-----
`),
"rsa": []byte(`-----BEGIN RSA PRIVATE KEY-----
MIIBOwIBAAJBALdGZxkXDAjsYk10ihwU6Id2KeILz1TAJuoq4tOgDWxEEGeTrcld
r/ZwVaFzjWzxaf6zQIJbfaSEAhqD5yo72+sCAwEAAQJBAK8PEVU23Wj8mV0QjwcJ
tZ4GcTUYQL7cF4+ezTCE9a1NrGnCP2RuQkHEKxuTVrxXt+6OF15/1/fuXnxKjmJC
nxkCIQDaXvPPBi0c7vAxGwNY9726x01/dNbHCE0CBtcotobxpwIhANbbQbh3JHVW
2haQh4fAG5mhesZKAGcxTyv4mQ7uMSQdAiAj+4dzMpJWdSzQ+qGHlHMIBvVHLkqB
y2VdEyF7DPCZewIhAI7GOI/6LDIFOvtPo6Bj2nNmyQ1HU6k/LRtNIXi4c9NJAiAr
rrxx26itVhJmcvoUhOjwuzSlP2bE5VHAvkGB352YBg==
-----END RSA PRIVATE KEY-----
`),
"user": []byte(`-----BEGIN EC PRIVATE KEY-----
MHcCAQEEILYCAeq8f7V4vSSypRw7pxy8yz3V5W4qg8kSC3zJhqpQoAoGCCqGSM49
AwEHoUQDQgAEYcO2xNKiRUYOLEHM7VYAp57HNyKbOdYtHD83Z4hzNPVC4tM5mdGD
PLL8IEwvYu2wq+lpXfGQnNMbzYf9gspG0w==
-----END EC PRIVATE KEY-----
`),
}

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modules/crypto/ssh/testdata_test.go
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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// IMPLEMENTOR NOTE: To avoid a package loop, this file is in three places:
// ssh/, ssh/agent, and ssh/test/. It should be kept in sync across all three
// instances.
package ssh
import (
"crypto/rand"
"fmt"
"github.com/gogits/gogs/modules/ssh/testdata"
)
var (
testPrivateKeys map[string]interface{}
testSigners map[string]Signer
testPublicKeys map[string]PublicKey
)
func init() {
var err error
n := len(testdata.PEMBytes)
testPrivateKeys = make(map[string]interface{}, n)
testSigners = make(map[string]Signer, n)
testPublicKeys = make(map[string]PublicKey, n)
for t, k := range testdata.PEMBytes {
testPrivateKeys[t], err = ParseRawPrivateKey(k)
if err != nil {
panic(fmt.Sprintf("Unable to parse test key %s: %v", t, err))
}
testSigners[t], err = NewSignerFromKey(testPrivateKeys[t])
if err != nil {
panic(fmt.Sprintf("Unable to create signer for test key %s: %v", t, err))
}
testPublicKeys[t] = testSigners[t].PublicKey()
}
// Create a cert and sign it for use in tests.
testCert := &Certificate{
Nonce: []byte{}, // To pass reflect.DeepEqual after marshal & parse, this must be non-nil
ValidPrincipals: []string{"gopher1", "gopher2"}, // increases test coverage
ValidAfter: 0, // unix epoch
ValidBefore: CertTimeInfinity, // The end of currently representable time.
Reserved: []byte{}, // To pass reflect.DeepEqual after marshal & parse, this must be non-nil
Key: testPublicKeys["ecdsa"],
SignatureKey: testPublicKeys["rsa"],
Permissions: Permissions{
CriticalOptions: map[string]string{},
Extensions: map[string]string{},
},
}
testCert.SignCert(rand.Reader, testSigners["rsa"])
testPrivateKeys["cert"] = testPrivateKeys["ecdsa"]
testSigners["cert"], err = NewCertSigner(testCert, testSigners["ecdsa"])
if err != nil {
panic(fmt.Sprintf("Unable to create certificate signer: %v", err))
}
}

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modules/crypto/ssh/transport.go
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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"bufio"
"errors"
"io"
)
const (
gcmCipherID = "aes128-gcm@openssh.com"
aes128cbcID = "aes128-cbc"
)
// packetConn represents a transport that implements packet based
// operations.
type packetConn interface {
// Encrypt and send a packet of data to the remote peer.
writePacket(packet []byte) error
// Read a packet from the connection
readPacket() ([]byte, error)
// Close closes the write-side of the connection.
Close() error
}
// transport is the keyingTransport that implements the SSH packet
// protocol.
type transport struct {
reader connectionState
writer connectionState
bufReader *bufio.Reader
bufWriter *bufio.Writer
rand io.Reader
io.Closer
// Initial H used for the session ID. Once assigned this does
// not change, even during subsequent key exchanges.
sessionID []byte
}
// getSessionID returns the ID of the SSH connection. The return value
// should not be modified.
func (t *transport) getSessionID() []byte {
if t.sessionID == nil {
panic("session ID not set yet")
}
return t.sessionID
}
// packetCipher represents a combination of SSH encryption/MAC
// protocol. A single instance should be used for one direction only.
type packetCipher interface {
// writePacket encrypts the packet and writes it to w. The
// contents of the packet are generally scrambled.
writePacket(seqnum uint32, w io.Writer, rand io.Reader, packet []byte) error
// readPacket reads and decrypts a packet of data. The
// returned packet may be overwritten by future calls of
// readPacket.
readPacket(seqnum uint32, r io.Reader) ([]byte, error)
}
// connectionState represents one side (read or write) of the
// connection. This is necessary because each direction has its own
// keys, and can even have its own algorithms
type connectionState struct {
packetCipher
seqNum uint32
dir direction
pendingKeyChange chan packetCipher
}
// prepareKeyChange sets up key material for a keychange. The key changes in
// both directions are triggered by reading and writing a msgNewKey packet
// respectively.
func (t *transport) prepareKeyChange(algs *algorithms, kexResult *kexResult) error {
if t.sessionID == nil {
t.sessionID = kexResult.H
}
kexResult.SessionID = t.sessionID
if ciph, err := newPacketCipher(t.reader.dir, algs.r, kexResult); err != nil {
return err
} else {
t.reader.pendingKeyChange <- ciph
}
if ciph, err := newPacketCipher(t.writer.dir, algs.w, kexResult); err != nil {
return err
} else {
t.writer.pendingKeyChange <- ciph
}
return nil
}
// Read and decrypt next packet.
func (t *transport) readPacket() ([]byte, error) {
return t.reader.readPacket(t.bufReader)
}
func (s *connectionState) readPacket(r *bufio.Reader) ([]byte, error) {
packet, err := s.packetCipher.readPacket(s.seqNum, r)
s.seqNum++
if err == nil && len(packet) == 0 {
err = errors.New("ssh: zero length packet")
}
if len(packet) > 0 && packet[0] == msgNewKeys {
select {
case cipher := <-s.pendingKeyChange:
s.packetCipher = cipher
default:
return nil, errors.New("ssh: got bogus newkeys message.")
}
}
// The packet may point to an internal buffer, so copy the
// packet out here.
fresh := make([]byte, len(packet))
copy(fresh, packet)
return fresh, err
}
func (t *transport) writePacket(packet []byte) error {
return t.writer.writePacket(t.bufWriter, t.rand, packet)
}
func (s *connectionState) writePacket(w *bufio.Writer, rand io.Reader, packet []byte) error {
changeKeys := len(packet) > 0 && packet[0] == msgNewKeys
err := s.packetCipher.writePacket(s.seqNum, w, rand, packet)
if err != nil {
return err
}
if err = w.Flush(); err != nil {
return err
}
s.seqNum++
if changeKeys {
select {
case cipher := <-s.pendingKeyChange:
s.packetCipher = cipher
default:
panic("ssh: no key material for msgNewKeys")
}
}
return err
}
func newTransport(rwc io.ReadWriteCloser, rand io.Reader, isClient bool) *transport {
t := &transport{
bufReader: bufio.NewReader(rwc),
bufWriter: bufio.NewWriter(rwc),
rand: rand,
reader: connectionState{
packetCipher: &streamPacketCipher{cipher: noneCipher{}},
pendingKeyChange: make(chan packetCipher, 1),
},
writer: connectionState{
packetCipher: &streamPacketCipher{cipher: noneCipher{}},
pendingKeyChange: make(chan packetCipher, 1),
},
Closer: rwc,
}
if isClient {
t.reader.dir = serverKeys
t.writer.dir = clientKeys
} else {
t.reader.dir = clientKeys
t.writer.dir = serverKeys
}
return t
}
type direction struct {
ivTag []byte
keyTag []byte
macKeyTag []byte
}
var (
serverKeys = direction{[]byte{'B'}, []byte{'D'}, []byte{'F'}}
clientKeys = direction{[]byte{'A'}, []byte{'C'}, []byte{'E'}}
)
// generateKeys generates key material for IV, MAC and encryption.
func generateKeys(d direction, algs directionAlgorithms, kex *kexResult) (iv, key, macKey []byte) {
cipherMode := cipherModes[algs.Cipher]
macMode := macModes[algs.MAC]
iv = make([]byte, cipherMode.ivSize)
key = make([]byte, cipherMode.keySize)
macKey = make([]byte, macMode.keySize)
generateKeyMaterial(iv, d.ivTag, kex)
generateKeyMaterial(key, d.keyTag, kex)
generateKeyMaterial(macKey, d.macKeyTag, kex)
return
}
// setupKeys sets the cipher and MAC keys from kex.K, kex.H and sessionId, as
// described in RFC 4253, section 6.4. direction should either be serverKeys
// (to setup server->client keys) or clientKeys (for client->server keys).
func newPacketCipher(d direction, algs directionAlgorithms, kex *kexResult) (packetCipher, error) {
iv, key, macKey := generateKeys(d, algs, kex)
if algs.Cipher == gcmCipherID {
return newGCMCipher(iv, key, macKey)
}
if algs.Cipher == aes128cbcID {
return newAESCBCCipher(iv, key, macKey, algs)
}
c := &streamPacketCipher{
mac: macModes[algs.MAC].new(macKey),
}
c.macResult = make([]byte, c.mac.Size())
var err error
c.cipher, err = cipherModes[algs.Cipher].createStream(key, iv)
if err != nil {
return nil, err
}
return c, nil
}
// generateKeyMaterial fills out with key material generated from tag, K, H
// and sessionId, as specified in RFC 4253, section 7.2.
func generateKeyMaterial(out, tag []byte, r *kexResult) {
var digestsSoFar []byte
h := r.Hash.New()
for len(out) > 0 {
h.Reset()
h.Write(r.K)
h.Write(r.H)
if len(digestsSoFar) == 0 {
h.Write(tag)
h.Write(r.SessionID)
} else {
h.Write(digestsSoFar)
}
digest := h.Sum(nil)
n := copy(out, digest)
out = out[n:]
if len(out) > 0 {
digestsSoFar = append(digestsSoFar, digest...)
}
}
}
const packageVersion = "SSH-2.0-Go"
// Sends and receives a version line. The versionLine string should
// be US ASCII, start with "SSH-2.0-", and should not include a
// newline. exchangeVersions returns the other side's version line.
func exchangeVersions(rw io.ReadWriter, versionLine []byte) (them []byte, err error) {
// Contrary to the RFC, we do not ignore lines that don't
// start with "SSH-2.0-" to make the library usable with
// nonconforming servers.
for _, c := range versionLine {
// The spec disallows non US-ASCII chars, and
// specifically forbids null chars.
if c < 32 {
return nil, errors.New("ssh: junk character in version line")
}
}
if _, err = rw.Write(append(versionLine, '\r', '\n')); err != nil {
return
}
them, err = readVersion(rw)
return them, err
}
// maxVersionStringBytes is the maximum number of bytes that we'll
// accept as a version string. RFC 4253 section 4.2 limits this at 255
// chars
const maxVersionStringBytes = 255
// Read version string as specified by RFC 4253, section 4.2.
func readVersion(r io.Reader) ([]byte, error) {
versionString := make([]byte, 0, 64)
var ok bool
var buf [1]byte
for len(versionString) < maxVersionStringBytes {
_, err := io.ReadFull(r, buf[:])
if err != nil {
return nil, err
}
// The RFC says that the version should be terminated with \r\n
// but several SSH servers actually only send a \n.
if buf[0] == '\n' {
ok = true
break
}
// non ASCII chars are disallowed, but we are lenient,
// since Go doesn't use null-terminated strings.
// The RFC allows a comment after a space, however,
// all of it (version and comments) goes into the
// session hash.
versionString = append(versionString, buf[0])
}
if !ok {
return nil, errors.New("ssh: overflow reading version string")
}
// There might be a '\r' on the end which we should remove.
if len(versionString) > 0 && versionString[len(versionString)-1] == '\r' {
versionString = versionString[:len(versionString)-1]
}
return versionString, nil
}

109
modules/crypto/ssh/transport_test.go
Unescape View File

@ -0,0 +1,109 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssh
import (
"bytes"
"crypto/rand"
"encoding/binary"
"strings"
"testing"
)
func TestReadVersion(t *testing.T) {
longversion := strings.Repeat("SSH-2.0-bla", 50)[:253]
cases := map[string]string{
"SSH-2.0-bla\r\n": "SSH-2.0-bla",
"SSH-2.0-bla\n": "SSH-2.0-bla",
longversion + "\r\n": longversion,
}
for in, want := range cases {
result, err := readVersion(bytes.NewBufferString(in))
if err != nil {
t.Errorf("readVersion(%q): %s", in, err)
}
got := string(result)
if got != want {
t.Errorf("got %q, want %q", got, want)
}
}
}
func TestReadVersionError(t *testing.T) {
longversion := strings.Repeat("SSH-2.0-bla", 50)[:253]
cases := []string{
longversion + "too-long\r\n",
}
for _, in := range cases {
if _, err := readVersion(bytes.NewBufferString(in)); err == nil {
t.Errorf("readVersion(%q) should have failed", in)
}
}
}
func TestExchangeVersionsBasic(t *testing.T) {
v := "SSH-2.0-bla"
buf := bytes.NewBufferString(v + "\r\n")
them, err := exchangeVersions(buf, []byte("xyz"))
if err != nil {
t.Errorf("exchangeVersions: %v", err)
}
if want := "SSH-2.0-bla"; string(them) != want {
t.Errorf("got %q want %q for our version", them, want)
}
}
func TestExchangeVersions(t *testing.T) {
cases := []string{
"not\x000allowed",
"not allowed\n",
}
for _, c := range cases {
buf := bytes.NewBufferString("SSH-2.0-bla\r\n")
if _, err := exchangeVersions(buf, []byte(c)); err == nil {
t.Errorf("exchangeVersions(%q): should have failed", c)
}
}
}
type closerBuffer struct {
bytes.Buffer
}
func (b *closerBuffer) Close() error {
return nil
}
func TestTransportMaxPacketWrite(t *testing.T) {
buf := &closerBuffer{}
tr := newTransport(buf, rand.Reader, true)
huge := make([]byte, maxPacket+1)
err := tr.writePacket(huge)
if err == nil {
t.Errorf("transport accepted write for a huge packet.")
}
}
func TestTransportMaxPacketReader(t *testing.T) {
var header [5]byte
huge := make([]byte, maxPacket+128)
binary.BigEndian.PutUint32(header[0:], uint32(len(huge)))
// padding.
header[4] = 0
buf := &closerBuffer{}
buf.Write(header[:])
buf.Write(huge)
tr := newTransport(buf, rand.Reader, true)
_, err := tr.readPacket()
if err == nil {
t.Errorf("transport succeeded reading huge packet.")
} else if !strings.Contains(err.Error(), "large") {
t.Errorf("got %q, should mention %q", err.Error(), "large")
}
}

2
modules/ssh/ssh.go
Unescape View File

@ -14,8 +14,8 @@ import (
"strings"
"github.com/Unknwon/com"
"golang.org/x/crypto/ssh"
"github.com/gogits/gogs/modules/crypto/ssh"
"github.com/gogits/gogs/modules/log"
)

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