Add support for FIDO U2F (#3971)

* Add support for U2F

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Add vendor library
Add missing translations

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Minor improvements

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Add U2F support for Firefox, Chrome (Android) by introducing a custom JS library
Add U2F error handling

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Add U2F login page to OAuth

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Move U2F user settings to a separate file

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Add unit tests for u2f model
Renamed u2f table name

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Fix problems caused by refactoring

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Add U2F documentation

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Remove not needed console.log-s

Signed-off-by: Jonas Franz <info@jonasfranz.software>

* Add default values to app.ini.sample
Add FIDO U2F to comparison

Signed-off-by: Jonas Franz <info@jonasfranz.software>

custom/conf/app.ini.sample

@@ -288,7 +288,7 @@ RESET_PASSWD_CODE_LIVE_MINUTES = 180
 REGISTER_EMAIL_CONFIRM = false
 ; Disallow registration, only allow admins to create accounts.
 DISABLE_REGISTRATION = false
-; Allow registration only using third part services, it works only when DISABLE_REGISTRATION is false 
+; Allow registration only using third part services, it works only when DISABLE_REGISTRATION is false
 ALLOW_ONLY_EXTERNAL_REGISTRATION = false
 ; User must sign in to view anything.
 REQUIRE_SIGNIN_VIEW = false
@@ -570,6 +570,14 @@ MAX_RESPONSE_ITEMS = 50
 LANGS = en-US,zh-CN,zh-HK,zh-TW,de-DE,fr-FR,nl-NL,lv-LV,ru-RU,ja-JP,es-ES,pt-BR,pl-PL,bg-BG,it-IT,fi-FI,tr-TR,cs-CZ,sr-SP,sv-SE,ko-KR
 NAMES = English,简体中文,繁體中文（香港）,繁體中文（台灣）,Deutsch,français,Nederlands,latviešu,русский,日本語,español,português do Brasil,polski,български,italiano,suomi,Türkçe,čeština,српски,svenska,한국어
 
+[U2F]
+; Two Factor authentication with security keys
+; https://developers.yubico.com/U2F/App_ID.html
+APP_ID = %(PROTOCOL)s://%(DOMAIN)s:%(HTTP_PORT)s
+; Comma seperated list of truisted facets
+TRUSTED_FACETS = %(PROTOCOL)s://%(DOMAIN)s:%(HTTP_PORT)s
+
+
 ; Used for datetimepicker
 [i18n.datelang]
 en-US = en

docs/content/doc/advanced/config-cheat-sheet.en-us.md

@@ -272,6 +272,10 @@ Values containing `#` or `;` must be quoted using `` ` `` or `"""`.
 - `MAX_GIT_DIFF_FILES`: **100**: Max number of files shown in diff view.
 - `GC_ARGS`: **\<empty\>**: Arguments for command `git gc`, e.g. `--aggressive --auto`.
 
+## U2F (`U2F`)
+- `APP_ID`: **`ROOT_URL`**: Declares the facet of the application. Requires HTTPS.
+- `TRUSTED_FACETS`: List of additional facets which are trusted. This is not support by all browsers.
+
 ## Markup (`markup`)
 
 Gitea can support Markup using external tools. The example below will add a markup named `asciidoc`.

docs/content/doc/features/comparison.en-us.md

@@ -535,6 +535,15 @@ _Symbols used in table:_
       <td>✓</td>
       <td>✓</td>
     </tr>
+    <tr>
+      <td>FIDO U2F (2FA)</td>
+      <td>✓</td>
+      <td>✘</td>
+      <td>✓</td>
+      <td>✓</td>
+      <td>✓</td>
+      <td>✓</td>
+    </tr>
     <tr>
       <td>Webhook support</td>
       <td>✓</td>

models/error.go

@@ -1237,3 +1237,25 @@ func IsErrExternalLoginUserNotExist(err error) bool {
 func (err ErrExternalLoginUserNotExist) Error() string {
 	return fmt.Sprintf("external login user link does not exists [userID: %d, loginSourceID: %d]", err.UserID, err.LoginSourceID)
 }
+
+// ____ ________________________________              .__          __                 __  .__
+// |    |   \_____  \_   _____/\______   \ ____   ____ |__| _______/  |_____________ _/  |_|__| ____   ____
+// |    |   //  ____/|    __)   |       _// __ \ / ___\|  |/  ___/\   __\_  __ \__  \\   __\  |/  _ \ /    \
+// |    |  //       \|     \    |    |   \  ___// /_/  >  |\___ \  |  |  |  | \// __ \|  | |  (  <_> )   |  \
+// |______/ \_______ \___  /    |____|_  /\___  >___  /|__/____  > |__|  |__|  (____  /__| |__|\____/|___|  /
+// \/   \/            \/     \/_____/         \/                   \/                    \/
+
+// ErrU2FRegistrationNotExist represents a "ErrU2FRegistrationNotExist" kind of error.
+type ErrU2FRegistrationNotExist struct {
+	ID int64
+}
+
+func (err ErrU2FRegistrationNotExist) Error() string {
+	return fmt.Sprintf("U2F registration does not exist [id: %d]", err.ID)
+}
+
+// IsErrU2FRegistrationNotExist checks if an error is a ErrU2FRegistrationNotExist.
+func IsErrU2FRegistrationNotExist(err error) bool {
+	_, ok := err.(ErrU2FRegistrationNotExist)
+	return ok
+}

models/fixtures/u2f_registration.yml

@@ -0,0 +1,7 @@
+-
+  id: 1
+  name: "U2F Key"
+  user_id: 1
+  counter: 0
+  created_unix: 946684800
+  updated_unix: 946684800

models/migrations/migrations.go

@@ -182,6 +182,8 @@ var migrations = []Migration{
 	NewMigration("add language column for user setting", addLanguageSetting),
 	// v64 -> v65
 	NewMigration("add multiple assignees", addMultipleAssignees),
+	// v65 -> v66
+	NewMigration("add u2f", addU2FReg),
 }
 
 // Migrate database to current version

models/migrations/v65.go

@@ -0,0 +1,19 @@
+package migrations
+
+import (
+	"code.gitea.io/gitea/modules/util"
+	"github.com/go-xorm/xorm"
+)
+
+func addU2FReg(x *xorm.Engine) error {
+	type U2FRegistration struct {
+		ID          int64 `xorm:"pk autoincr"`
+		Name        string
+		UserID      int64 `xorm:"INDEX"`
+		Raw         []byte
+		Counter     uint32
+		CreatedUnix util.TimeStamp `xorm:"INDEX created"`
+		UpdatedUnix util.TimeStamp `xorm:"INDEX updated"`
+	}
+	return x.Sync2(&U2FRegistration{})
+}

models/models.go

@@ -120,6 +120,7 @@ func init() {
 		new(LFSLock),
 		new(Reaction),
 		new(IssueAssignees),
+		new(U2FRegistration),
 	)
 
 	gonicNames := []string{"SSL", "UID"}

models/u2f.go

@@ -0,0 +1,120 @@
+// Copyright 2018 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package models
+
+import (
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/util"
+
+	"github.com/tstranex/u2f"
+)
+
+// U2FRegistration represents the registration data and counter of a security key
+type U2FRegistration struct {
+	ID          int64 `xorm:"pk autoincr"`
+	Name        string
+	UserID      int64 `xorm:"INDEX"`
+	Raw         []byte
+	Counter     uint32
+	CreatedUnix util.TimeStamp `xorm:"INDEX created"`
+	UpdatedUnix util.TimeStamp `xorm:"INDEX updated"`
+}
+
+// TableName returns a better table name for U2FRegistration
+func (reg U2FRegistration) TableName() string {
+	return "u2f_registration"
+}
+
+// Parse will convert the db entry U2FRegistration to an u2f.Registration struct
+func (reg *U2FRegistration) Parse() (*u2f.Registration, error) {
+	r := new(u2f.Registration)
+	return r, r.UnmarshalBinary(reg.Raw)
+}
+
+func (reg *U2FRegistration) updateCounter(e Engine) error {
+	_, err := e.ID(reg.ID).Cols("counter").Update(reg)
+	return err
+}
+
+// UpdateCounter will update the database value of counter
+func (reg *U2FRegistration) UpdateCounter() error {
+	return reg.updateCounter(x)
+}
+
+// U2FRegistrationList is a list of *U2FRegistration
+type U2FRegistrationList []*U2FRegistration
+
+// ToRegistrations will convert all U2FRegistrations to u2f.Registrations
+func (list U2FRegistrationList) ToRegistrations() []u2f.Registration {
+	regs := make([]u2f.Registration, len(list))
+	for _, reg := range list {
+		r, err := reg.Parse()
+		if err != nil {
+			log.Fatal(4, "parsing u2f registration: %v", err)
+			continue
+		}
+		regs = append(regs, *r)
+	}
+
+	return regs
+}
+
+func getU2FRegistrationsByUID(e Engine, uid int64) (U2FRegistrationList, error) {
+	regs := make(U2FRegistrationList, 0)
+	return regs, e.Where("user_id = ?", uid).Find(&regs)
+}
+
+// GetU2FRegistrationByID returns U2F registration by id
+func GetU2FRegistrationByID(id int64) (*U2FRegistration, error) {
+	return getU2FRegistrationByID(x, id)
+}
+
+func getU2FRegistrationByID(e Engine, id int64) (*U2FRegistration, error) {
+	reg := new(U2FRegistration)
+	if found, err := e.ID(id).Get(reg); err != nil {
+		return nil, err
+	} else if !found {
+		return nil, ErrU2FRegistrationNotExist{ID: id}
+	}
+	return reg, nil
+}
+
+// GetU2FRegistrationsByUID returns all U2F registrations of the given user
+func GetU2FRegistrationsByUID(uid int64) (U2FRegistrationList, error) {
+	return getU2FRegistrationsByUID(x, uid)
+}
+
+func createRegistration(e Engine, user *User, name string, reg *u2f.Registration) (*U2FRegistration, error) {
+	raw, err := reg.MarshalBinary()
+	if err != nil {
+		return nil, err
+	}
+	r := &U2FRegistration{
+		UserID:  user.ID,
+		Name:    name,
+		Counter: 0,
+		Raw:     raw,
+	}
+	_, err = e.InsertOne(r)
+	if err != nil {
+		return nil, err
+	}
+	return r, nil
+}
+
+// CreateRegistration will create a new U2FRegistration from the given Registration
+func CreateRegistration(user *User, name string, reg *u2f.Registration) (*U2FRegistration, error) {
+	return createRegistration(x, user, name, reg)
+}
+
+// DeleteRegistration will delete U2FRegistration
+func DeleteRegistration(reg *U2FRegistration) error {
+	return deleteRegistration(x, reg)
+}
+
+func deleteRegistration(e Engine, reg *U2FRegistration) error {
+	_, err := e.Delete(reg)
+	return err
+}

models/u2f_test.go

@@ -0,0 +1,61 @@
+package models
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/tstranex/u2f"
+)
+
+func TestGetU2FRegistrationByID(t *testing.T) {
+	assert.NoError(t, PrepareTestDatabase())
+
+	res, err := GetU2FRegistrationByID(1)
+	assert.NoError(t, err)
+	assert.Equal(t, "U2F Key", res.Name)
+
+	_, err = GetU2FRegistrationByID(342432)
+	assert.Error(t, err)
+	assert.True(t, IsErrU2FRegistrationNotExist(err))
+}
+
+func TestGetU2FRegistrationsByUID(t *testing.T) {
+	assert.NoError(t, PrepareTestDatabase())
+
+	res, err := GetU2FRegistrationsByUID(1)
+	assert.NoError(t, err)
+	assert.Len(t, res, 1)
+	assert.Equal(t, "U2F Key", res[0].Name)
+}
+
+func TestU2FRegistration_TableName(t *testing.T) {
+	assert.Equal(t, "u2f_registration", U2FRegistration{}.TableName())
+}
+
+func TestU2FRegistration_UpdateCounter(t *testing.T) {
+	assert.NoError(t, PrepareTestDatabase())
+	reg := AssertExistsAndLoadBean(t, &U2FRegistration{ID: 1}).(*U2FRegistration)
+	reg.Counter = 1
+	assert.NoError(t, reg.UpdateCounter())
+	AssertExistsIf(t, true, &U2FRegistration{ID: 1, Counter: 1})
+}
+
+func TestCreateRegistration(t *testing.T) {
+	assert.NoError(t, PrepareTestDatabase())
+	user := AssertExistsAndLoadBean(t, &User{ID: 1}).(*User)
+
+	res, err := CreateRegistration(user, "U2F Created Key", &u2f.Registration{Raw: []byte("Test")})
+	assert.NoError(t, err)
+	assert.Equal(t, "U2F Created Key", res.Name)
+	assert.Equal(t, []byte("Test"), res.Raw)
+
+	AssertExistsIf(t, true, &U2FRegistration{Name: "U2F Created Key", UserID: user.ID})
+}
+
+func TestDeleteRegistration(t *testing.T) {
+	assert.NoError(t, PrepareTestDatabase())
+	reg := AssertExistsAndLoadBean(t, &U2FRegistration{ID: 1}).(*U2FRegistration)
+
+	assert.NoError(t, DeleteRegistration(reg))
+	AssertNotExistsBean(t, &U2FRegistration{ID: 1})
+}

modules/auth/user_form.go

@@ -211,3 +211,23 @@ type TwoFactorScratchAuthForm struct {
 func (f *TwoFactorScratchAuthForm) Validate(ctx *macaron.Context, errs binding.Errors) binding.Errors {
 	return validate(errs, ctx.Data, f, ctx.Locale)
 }
+
+// U2FRegistrationForm for reserving an U2F name
+type U2FRegistrationForm struct {
+	Name string `binding:"Required"`
+}
+
+// Validate valideates the fields
+func (f *U2FRegistrationForm) Validate(ctx *macaron.Context, errs binding.Errors) binding.Errors {
+	return validate(errs, ctx.Data, f, ctx.Locale)
+}
+
+// U2FDeleteForm for deleting U2F keys
+type U2FDeleteForm struct {
+	ID int64 `binding:"Required"`
+}
+
+// Validate valideates the fields
+func (f *U2FDeleteForm) Validate(ctx *macaron.Context, errs binding.Errors) binding.Errors {
+	return validate(errs, ctx.Data, f, ctx.Locale)
+}

modules/setting/setting.go

@@ -521,6 +521,11 @@ var (
 		MaxResponseItems:      50,
 	}
 
+	U2F = struct {
+		AppID         string
+		TrustedFacets []string
+	}{}
+
 	// I18n settings
 	Langs     []string
 	Names     []string
@@ -1135,6 +1140,9 @@ func NewContext() {
 			IsInputFile:    sec.Key("IS_INPUT_FILE").MustBool(false),
 		})
 	}
+	sec = Cfg.Section("U2F")
+	U2F.TrustedFacets, _ = shellquote.Split(sec.Key("TRUSTED_FACETS").MustString(strings.TrimRight(AppURL, "/")))
+	U2F.AppID = sec.Key("APP_ID").MustString(strings.TrimRight(AppURL, "/"))
 }
 
 // Service settings

options/locale/locale_en-US.ini

@@ -31,6 +31,19 @@ twofa = Two-Factor Authentication
 twofa_scratch = Two-Factor Scratch Code
 passcode = Passcode
 
+u2f_insert_key = Insert your security key
+u2f_sign_in = Press the button on your security key. If you can't find a button, re-insert it.
+u2f_press_button = Please press the button on your security key…
+u2f_use_twofa = Use a two-factor code from your phone
+u2f_error = We can't read your security key!
+u2f_unsupported_browser = Your browser don't support U2F keys. Please try another browser.
+u2f_error_1 = An unknown error occured. Please retry.
+u2f_error_2 = Please make sure that you're using an encrypted connection (https://) and visiting the correct URL.
+u2f_error_3 = The server could not proceed your request.
+u2f_error_4 = The presented key is not eligible for this request. If you try to register it, make sure that the key isn't already registered.
+u2f_error_5 = Timeout reached before your key could be read. Please reload to retry.
+u2f_reload = Reload
+
 repository = Repository
 organization = Organization
 mirror = Mirror
@@ -320,6 +333,7 @@ twofa = Two-Factor Authentication
 account_link = Linked Accounts
 organization = Organizations
 uid = Uid
+u2f = Security Keys
 
 public_profile = Public Profile
 profile_desc = Your email address will be used for notifications and other operations.
@@ -449,6 +463,14 @@ then_enter_passcode = And enter the passcode shown in the application:
 passcode_invalid = The passcode is incorrect. Try again.
 twofa_enrolled = Your account has been enrolled into two-factor authentication. Store your scratch token (%s) in a safe place as it is only shown once!
 
+u2f_desc = Security keys are hardware devices containing cryptograhic keys. They could be used for two factor authentication. The security key must support the <a href="https://fidoalliance.org/">FIDO U2F</a> standard.
+u2f_require_twofa = Two-Factor-Authentication must be enrolled in order to use security keys.
+u2f_register_key = Add Security Key
+u2f_nickname = Nickname
+u2f_press_button = Press the button on your security key to register it.
+u2f_delete_key = Remove Security Key
+u2f_delete_key_desc= If you remove a security key you cannot login with it anymore. Are you sure?
+
 manage_account_links = Manage Linked Accounts
 manage_account_links_desc = These external accounts are linked to your Gitea account.
 account_links_not_available = There are currently no external accounts linked to your Gitea account.

public/js/index.js

@@ -1432,6 +1432,130 @@ function initCodeView() {
     }
 }
 
+function initU2FAuth() {
+    if($('#wait-for-key').length === 0) {
+        return
+    }
+    u2fApi.ensureSupport()
+        .then(function () {
+            $.getJSON('/user/u2f/challenge').success(function(req) {
+                u2fApi.sign(req.appId, req.challenge, req.registeredKeys, 30)
+                    .then(u2fSigned)
+                    .catch(function (err) {
+                        if(err === undefined) {
+                            u2fError(1);
+                            return
+                        }
+                        u2fError(err.metaData.code);
+                    });
+            });
+        }).catch(function () {
+            // Fallback in case browser do not support U2F
+            window.location.href = "/user/two_factor"
+        })
+}
+function u2fSigned(resp) {
+    $.ajax({
+        url:'/user/u2f/sign',
+        type:"POST",
+        headers: {"X-Csrf-Token": csrf},
+        data: JSON.stringify(resp),
+        contentType:"application/json; charset=utf-8",
+    }).done(function(res){
+        window.location.replace(res);
+    }).fail(function (xhr, textStatus) {
+        u2fError(1);
+    });
+}
+
+function u2fRegistered(resp) {
+    if (checkError(resp)) {
+        return;
+    }
+    $.ajax({
+        url:'/user/settings/security/u2f/register',
+        type:"POST",
+        headers: {"X-Csrf-Token": csrf},
+        data: JSON.stringify(resp),
+        contentType:"application/json; charset=utf-8",
+        success: function(){
+            window.location.reload();
+        },
+        fail: function (xhr, textStatus) {
+            u2fError(1);
+        }
+    });
+}
+
+function checkError(resp) {
+    if (!('errorCode' in resp)) {
+        return false;
+    }
+    if (resp.errorCode === 0) {
+        return false;
+    }
+    u2fError(resp.errorCode);
+    return true;
+}
+
+
+function u2fError(errorType) {
+    var u2fErrors = {
+        'browser': $('#unsupported-browser'),
+        1: $('#u2f-error-1'),
+        2: $('#u2f-error-2'),
+        3: $('#u2f-error-3'),
+        4: $('#u2f-error-4'),
+        5: $('.u2f-error-5')
+    };
+    u2fErrors[errorType].removeClass('hide');
+    for(var type in u2fErrors){
+        if(type != errorType){
+            u2fErrors[type].addClass('hide');
+        }
+    }
+    $('#u2f-error').modal('show');
+}
+
+function initU2FRegister() {
+    $('#register-device').modal({allowMultiple: false});
+    $('#u2f-error').modal({allowMultiple: false});
+    $('#register-security-key').on('click', function(e) {
+        e.preventDefault();
+        u2fApi.ensureSupport()
+            .then(u2fRegisterRequest)
+            .catch(function() {
+                u2fError('browser');
+            })
+    })
+}
+
+function u2fRegisterRequest() {
+    $.post("/user/settings/security/u2f/request_register", {
+        "_csrf": csrf,
+        "name": $('#nickname').val()
+    }).success(function(req) {
+        $("#nickname").closest("div.field").removeClass("error");
+        $('#register-device').modal('show');
+        if(req.registeredKeys === null) {
+            req.registeredKeys = []
+        }
+        u2fApi.register(req.appId, req.registerRequests, req.registeredKeys, 30)
+            .then(u2fRegistered)
+            .catch(function (reason) {
+                if(reason === undefined) {
+                    u2fError(1);
+                    return
+                }
+                u2fError(reason.metaData.code);
+            });
+    }).fail(function(xhr, status, error) {
+        if(xhr.status === 409) {
+            $("#nickname").closest("div.field").addClass("error");
+        }
+    });
+}
+
 $(document).ready(function () {
     csrf = $('meta[name=_csrf]').attr("content");
     suburl = $('meta[name=_suburl]').attr("content");
@@ -1643,6 +1767,8 @@ $(document).ready(function () {
     initCtrlEnterSubmit();
     initNavbarContentToggle();
     initTopicbar();
+    initU2FAuth();
+    initU2FRegister();
 
     // Repo clone url.
     if ($('#repo-clone-url').length > 0) {
@@ -2201,7 +2327,7 @@ function initTopicbar() {
                     return
                 }
                 var topicArray = topics.split(",");
-                
+
                 var last = viewDiv.children("a").last();
                 for (var i=0;i < topicArray.length; i++) {
                     $('<div class="ui green basic label topic" style="cursor:pointer;">'+topicArray[i]+'</div>').insertBefore(last)

public/vendor/librejs.html

@@ -110,6 +110,11 @@
           <td><a href="https://github.com/mozilla/pdf.js/blob/master/LICENSE">Apache-2.0-only</a></td>
           <td><a href="https://github.com/mozilla/pdf.js/archive/v1.4.20.tar.gz">pdf.js-v1.4.20.tar.gz</a></td>
         </tr>
+		<tr>
+		  <td><a href="/vendor/plugins/u2f/">u2f-api</a></td>
+		  <td><a href="https://github.com/go-gitea/u2f-api/blob/master/LICENSE">Expat</a></td>
+		  <td><a href="https://github.com/go-gitea/u2f-api/archive/v1.0.8.zip">u2f-api-1.0.8.zip</a></td>
+		</tr>
         <tr>
           <td><a href="/vendor/assets/font-awesome/fonts/">font-awesome - fonts</a></td>
           <td><a href="http://fontawesome.io/license/">OFL</a></td>

routers/routes/routes.go

@@ -5,6 +5,8 @@
 package routes
 
 import (
+	"encoding/gob"
+	"net/http"
 	"os"
 	"path"
 	"time"
@@ -37,12 +39,13 @@ import (
 	"github.com/go-macaron/i18n"
 	"github.com/go-macaron/session"
 	"github.com/go-macaron/toolbox"
+	"github.com/tstranex/u2f"
 	"gopkg.in/macaron.v1"
-	"net/http"
 )
 
 // NewMacaron initializes Macaron instance.
 func NewMacaron() *macaron.Macaron {
+	gob.Register(&u2f.Challenge{})
 	m := macaron.New()
 	if !setting.DisableRouterLog {
 		m.Use(macaron.Logger())
@@ -214,6 +217,12 @@ func RegisterRoutes(m *macaron.Macaron) {
 			m.Get("/scratch", user.TwoFactorScratch)
 			m.Post("/scratch", bindIgnErr(auth.TwoFactorScratchAuthForm{}), user.TwoFactorScratchPost)
 		})
+		m.Group("/u2f", func() {
+			m.Get("", user.U2F)
+			m.Get("/challenge", user.U2FChallenge)
+			m.Post("/sign", bindIgnErr(u2f.SignResponse{}), user.U2FSign)
+
+		})
 	}, reqSignOut)
 
 	m.Group("/user/settings", func() {
@@ -235,6 +244,11 @@ func RegisterRoutes(m *macaron.Macaron) {
 				m.Get("/enroll", userSetting.EnrollTwoFactor)
 				m.Post("/enroll", bindIgnErr(auth.TwoFactorAuthForm{}), userSetting.EnrollTwoFactorPost)
 			})
+			m.Group("/u2f", func() {
+				m.Post("/request_register", bindIgnErr(auth.U2FRegistrationForm{}), userSetting.U2FRegister)
+				m.Post("/register", bindIgnErr(u2f.RegisterResponse{}), userSetting.U2FRegisterPost)
+				m.Post("/delete", bindIgnErr(auth.U2FDeleteForm{}), userSetting.U2FDelete)
+			})
 			m.Group("/openid", func() {
 				m.Post("", bindIgnErr(auth.AddOpenIDForm{}), userSetting.OpenIDPost)
 				m.Post("/delete", userSetting.DeleteOpenID)

routers/user/auth.go

@@ -21,6 +21,7 @@ import (
 
 	"github.com/go-macaron/captcha"
 	"github.com/markbates/goth"
+	"github.com/tstranex/u2f"
 )
 
 const (
@@ -35,6 +36,7 @@ const (
 	tplTwofa          base.TplName = "user/auth/twofa"
 	tplTwofaScratch   base.TplName = "user/auth/twofa_scratch"
 	tplLinkAccount    base.TplName = "user/auth/link_account"
+	tplU2F            base.TplName = "user/auth/u2f"
 )
 
 // AutoSignIn reads cookie and try to auto-login.
@@ -159,7 +161,6 @@ func SignInPost(ctx *context.Context, form auth.SignInForm) {
 		}
 		return
 	}
-
 	// If this user is enrolled in 2FA, we can't sign the user in just yet.
 	// Instead, redirect them to the 2FA authentication page.
 	_, err = models.GetTwoFactorByUID(u.ID)
@@ -175,6 +176,13 @@ func SignInPost(ctx *context.Context, form auth.SignInForm) {
 	// User needs to use 2FA, save data and redirect to 2FA page.
 	ctx.Session.Set("twofaUid", u.ID)
 	ctx.Session.Set("twofaRemember", form.Remember)
+
+	regs, err := models.GetU2FRegistrationsByUID(u.ID)
+	if err == nil && len(regs) > 0 {
+		ctx.Redirect(setting.AppSubURL + "/user/u2f")
+		return
+	}
+
 	ctx.Redirect(setting.AppSubURL + "/user/two_factor")
 }
 
@@ -317,12 +325,115 @@ func TwoFactorScratchPost(ctx *context.Context, form auth.TwoFactorScratchAuthFo
 	ctx.RenderWithErr(ctx.Tr("auth.twofa_scratch_token_incorrect"), tplTwofaScratch, auth.TwoFactorScratchAuthForm{})
 }
 
+// U2F shows the U2F login page
+func U2F(ctx *context.Context) {
+	ctx.Data["Title"] = ctx.Tr("twofa")
+	ctx.Data["RequireU2F"] = true
+	// Check auto-login.
+	if checkAutoLogin(ctx) {
+		return
+	}
+
+	// Ensure user is in a 2FA session.
+	if ctx.Session.Get("twofaUid") == nil {
+		ctx.ServerError("UserSignIn", errors.New("not in U2F session"))
+		return
+	}
+
+	ctx.HTML(200, tplU2F)
+}
+
+// U2FChallenge submits a sign challenge to the browser
+func U2FChallenge(ctx *context.Context) {
+	// Ensure user is in a U2F session.
+	idSess := ctx.Session.Get("twofaUid")
+	if idSess == nil {
+		ctx.ServerError("UserSignIn", errors.New("not in U2F session"))
+		return
+	}
+	id := idSess.(int64)
+	regs, err := models.GetU2FRegistrationsByUID(id)
+	if err != nil {
+		ctx.ServerError("UserSignIn", err)
+		return
+	}
+	if len(regs) == 0 {
+		ctx.ServerError("UserSignIn", errors.New("no device registered"))
+		return
+	}
+	challenge, err := u2f.NewChallenge(setting.U2F.AppID, setting.U2F.TrustedFacets)
+	if err = ctx.Session.Set("u2fChallenge", challenge); err != nil {
+		ctx.ServerError("UserSignIn", err)
+		return
+	}
+	ctx.JSON(200, challenge.SignRequest(regs.ToRegistrations()))
+}
+
+// U2FSign authenticates the user by signResp
+func U2FSign(ctx *context.Context, signResp u2f.SignResponse) {
+	challSess := ctx.Session.Get("u2fChallenge")
+	idSess := ctx.Session.Get("twofaUid")
+	if challSess == nil || idSess == nil {
+		ctx.ServerError("UserSignIn", errors.New("not in U2F session"))
+		return
+	}
+	challenge := challSess.(*u2f.Challenge)
+	id := idSess.(int64)
+	regs, err := models.GetU2FRegistrationsByUID(id)
+	if err != nil {
+		ctx.ServerError("UserSignIn", err)
+		return
+	}
+	for _, reg := range regs {
+		r, err := reg.Parse()
+		if err != nil {
+			log.Fatal(4, "parsing u2f registration: %v", err)
+			continue
+		}
+		newCounter, authErr := r.Authenticate(signResp, *challenge, reg.Counter)
+		if authErr == nil {
+			reg.Counter = newCounter
+			user, err := models.GetUserByID(id)
+			if err != nil {
+				ctx.ServerError("UserSignIn", err)
+				return
+			}
+			remember := ctx.Session.Get("twofaRemember").(bool)
+			if err := reg.UpdateCounter(); err != nil {
+				ctx.ServerError("UserSignIn", err)
+				return
+			}
+
+			if ctx.Session.Get("linkAccount") != nil {
+				gothUser := ctx.Session.Get("linkAccountGothUser")
+				if gothUser == nil {
+					ctx.ServerError("UserSignIn", errors.New("not in LinkAccount session"))
+					return
+				}
+
+				err = models.LinkAccountToUser(user, gothUser.(goth.User))
+				if err != nil {
+					ctx.ServerError("UserSignIn", err)
+					return
+				}
+			}
+			redirect := handleSignInFull(ctx, user, remember, false)
+			if redirect == "" {
+				redirect = setting.AppSubURL + "/"
+			}
+			ctx.PlainText(200, []byte(redirect))
+			return
+		}
+	}
+	ctx.Error(401)
+}
+
 // This handles the final part of the sign-in process of the user.
 func handleSignIn(ctx *context.Context, u *models.User, remember bool) {
 	handleSignInFull(ctx, u, remember, true)
 }
 
-func handleSignInFull(ctx *context.Context, u *models.User, remember bool, obeyRedirect bool) {
+func handleSignInFull(ctx *context.Context, u *models.User, remember bool, obeyRedirect bool) string {
 	if remember {
 		days := 86400 * setting.LogInRememberDays
 		ctx.SetCookie(setting.CookieUserName, u.Name, days, setting.AppSubURL)
@@ -336,6 +447,8 @@ func handleSignInFull(ctx *context.Context, u *models.User, remember bool, obeyR
 	ctx.Session.Delete("openid_determined_username")
 	ctx.Session.Delete("twofaUid")
 	ctx.Session.Delete("twofaRemember")
+	ctx.Session.Delete("u2fChallenge")
+	ctx.Session.Delete("linkAccount")
 	ctx.Session.Set("uid", u.ID)
 	ctx.Session.Set("uname", u.Name)
 
@@ -345,7 +458,7 @@ func handleSignInFull(ctx *context.Context, u *models.User, remember bool, obeyR
 		u.Language = ctx.Locale.Language()
 		if err := models.UpdateUserCols(u, "language"); err != nil {
 			log.Error(4, fmt.Sprintf("Error updating user language [user: %d, locale: %s]", u.ID, u.Language))
-			return
+			return setting.AppSubURL + "/"
 		}
 	}
 
@@ -358,7 +471,7 @@ func handleSignInFull(ctx *context.Context, u *models.User, remember bool, obeyR
 	u.SetLastLogin()
 	if err := models.UpdateUserCols(u, "last_login_unix"); err != nil {
 		ctx.ServerError("UpdateUserCols", err)
-		return
+		return setting.AppSubURL + "/"
 	}
 
 	if redirectTo, _ := url.QueryUnescape(ctx.GetCookie("redirect_to")); len(redirectTo) > 0 {
@@ -366,12 +479,13 @@ func handleSignInFull(ctx *context.Context, u *models.User, remember bool, obeyR
 		if obeyRedirect {
 			ctx.RedirectToFirst(redirectTo)
 		}
-		return
+		return redirectTo
 	}
 
 	if obeyRedirect {
 		ctx.Redirect(setting.AppSubURL + "/")
 	}
+	return setting.AppSubURL + "/"
 }
 
 // SignInOAuth handles the OAuth2 login buttons
@@ -467,6 +581,14 @@ func handleOAuth2SignIn(u *models.User, gothUser goth.User, ctx *context.Context
 	// User needs to use 2FA, save data and redirect to 2FA page.
 	ctx.Session.Set("twofaUid", u.ID)
 	ctx.Session.Set("twofaRemember", false)
+
+	// If U2F is enrolled -> Redirect to U2F instead
+	regs, err := models.GetU2FRegistrationsByUID(u.ID)
+	if err == nil && len(regs) > 0 {
+		ctx.Redirect(setting.AppSubURL + "/user/u2f")
+		return
+	}
+
 	ctx.Redirect(setting.AppSubURL + "/user/two_factor")
 }
 
@@ -593,6 +715,13 @@ func LinkAccountPostSignIn(ctx *context.Context, signInForm auth.SignInForm) {
 	ctx.Session.Set("twofaRemember", signInForm.Remember)
 	ctx.Session.Set("linkAccount", true)
 
+	// If U2F is enrolled -> Redirect to U2F instead
+	regs, err := models.GetU2FRegistrationsByUID(u.ID)
+	if err == nil && len(regs) > 0 {
+		ctx.Redirect(setting.AppSubURL + "/user/u2f")
+		return
+	}
+
 	ctx.Redirect(setting.AppSubURL + "/user/two_factor")
 }
 

routers/user/setting/security.go

@@ -33,6 +33,14 @@ func Security(ctx *context.Context) {
 		}
 	}
 	ctx.Data["TwofaEnrolled"] = enrolled
+	if enrolled {
+		ctx.Data["U2FRegistrations"], err = models.GetU2FRegistrationsByUID(ctx.User.ID)
+		if err != nil {
+			ctx.ServerError("GetU2FRegistrationsByUID", err)
+			return
+		}
+		ctx.Data["RequireU2F"] = true
+	}
 
 	tokens, err := models.ListAccessTokens(ctx.User.ID)
 	if err != nil {

routers/user/setting/security_u2f.go

@@ -0,0 +1,99 @@
+// Copyright 2018 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package setting
+
+import (
+	"errors"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/auth"
+	"code.gitea.io/gitea/modules/context"
+	"code.gitea.io/gitea/modules/setting"
+
+	"github.com/tstranex/u2f"
+)
+
+// U2FRegister initializes the u2f registration procedure
+func U2FRegister(ctx *context.Context, form auth.U2FRegistrationForm) {
+	if form.Name == "" {
+		ctx.Error(409)
+		return
+	}
+	challenge, err := u2f.NewChallenge(setting.U2F.AppID, setting.U2F.TrustedFacets)
+	if err != nil {
+		ctx.ServerError("NewChallenge", err)
+		return
+	}
+	err = ctx.Session.Set("u2fChallenge", challenge)
+	if err != nil {
+		ctx.ServerError("Session.Set", err)
+		return
+	}
+	regs, err := models.GetU2FRegistrationsByUID(ctx.User.ID)
+	if err != nil {
+		ctx.ServerError("GetU2FRegistrationsByUID", err)
+		return
+	}
+	for _, reg := range regs {
+		if reg.Name == form.Name {
+			ctx.Error(409, "Name already taken")
+			return
+		}
+	}
+	ctx.Session.Set("u2fName", form.Name)
+	ctx.JSON(200, u2f.NewWebRegisterRequest(challenge, regs.ToRegistrations()))
+}
+
+// U2FRegisterPost receives the response of the security key
+func U2FRegisterPost(ctx *context.Context, response u2f.RegisterResponse) {
+	challSess := ctx.Session.Get("u2fChallenge")
+	u2fName := ctx.Session.Get("u2fName")
+	if challSess == nil || u2fName == nil {
+		ctx.ServerError("U2FRegisterPost", errors.New("not in U2F session"))
+		return
+	}
+	challenge := challSess.(*u2f.Challenge)
+	name := u2fName.(string)
+	config := &u2f.Config{
+		// Chrome 66+ doesn't return the device's attestation
+		// certificate by default.
+		SkipAttestationVerify: true,
+	}
+	reg, err := u2f.Register(response, *challenge, config)
+	if err != nil {
+		ctx.ServerError("u2f.Register", err)
+		return
+	}
+	if _, err = models.CreateRegistration(ctx.User, name, reg); err != nil {
+		ctx.ServerError("u2f.Register", err)
+		return
+	}
+	ctx.Status(200)
+}
+
+// U2FDelete deletes an security key by id
+func U2FDelete(ctx *context.Context, form auth.U2FDeleteForm) {
+	reg, err := models.GetU2FRegistrationByID(form.ID)
+	if err != nil {
+		if models.IsErrU2FRegistrationNotExist(err) {
+			ctx.Status(200)
+			return
+		}
+		ctx.ServerError("GetU2FRegistrationByID", err)
+		return
+	}
+	if reg.UserID != ctx.User.ID {
+		ctx.Status(401)
+		return
+	}
+	if err := models.DeleteRegistration(reg); err != nil {
+		ctx.ServerError("DeleteRegistration", err)
+		return
+	}
+	ctx.JSON(200, map[string]interface{}{
+		"redirect": setting.AppSubURL + "/user/settings/security",
+	})
+	return
+}

templates/base/footer.tmpl

@@ -64,6 +64,9 @@
 {{if .RequireDropzone}}
 	<script src="{{AppSubUrl}}/vendor/plugins/dropzone/dropzone.js"></script>
 {{end}}
+{{if .RequireU2F}}
+	<script src="{{AppSubUrl}}/vendor/plugins/u2f/index.js"></script>
+{{end}}
 {{if .RequireTribute}}
 	<script src="{{AppSubUrl}}/vendor/plugins/tribute/tribute.min.js"></script>
 

templates/user/auth/u2f.tmpl

@@ -0,0 +1,22 @@
+{{template "base/head" .}}
+<div class="user signin">
+	<div class="ui middle centered very relaxed page grid">
+		<div class="column">
+			<h3 class="ui top attached header">
+			{{.i18n.Tr "twofa"}}
+			</h3>
+			<div class="ui attached segment">
+				<i class="huge key icon"></i>
+				<h3>{{.i18n.Tr "u2f_insert_key"}}</h3>
+				{{template "base/alert" .}}
+				<p>{{.i18n.Tr "u2f_sign_in"}}</p>
+			</div>
+			<div id="wait-for-key" class="ui attached segment"><div class="ui active indeterminate inline loader"></div> {{.i18n.Tr "u2f_press_button"}} </div>
+			<div class="ui attached segment">
+				<a href="/user/two_factor">{{.i18n.Tr "u2f_use_twofa"}}</a>
+			</div>
+		</div>
+	</div>
+</div>
+{{template "user/auth/u2f_error" .}}
+{{template "base/footer" .}}

templates/user/auth/u2f_error.tmpl

@@ -0,0 +1,32 @@
+<div class="ui small modal" id="u2f-error">
+	<div class="header">{{.i18n.Tr "u2f_error"}}</div>
+	<div class="content">
+		<div class="ui negative message">
+			<div class="header">
+			{{.i18n.Tr "u2f_error"}}
+			</div>
+			<div class="hide" id="unsupported-browser">
+			{{.i18n.Tr "u2f_unsupported_browser"}}
+			</div>
+			<div class="hide" id="u2f-error-1">
+			{{.i18n.Tr "u2f_error_1"}}
+			</div>
+			<div class="hide" id="u2f-error-2">
+			{{.i18n.Tr "u2f_error_2"}}
+			</div>
+			<div class="hide" id="u2f-error-3">
+			{{.i18n.Tr "u2f_error_3"}}
+			</div>
+			<div class="hide" id="u2f-error-4">
+			{{.i18n.Tr "u2f_error_4"}}
+			</div>
+			<div class="hide u2f-error-5">
+			{{.i18n.Tr "u2f_error_5"}}
+			</div>
+		</div>
+	</div>
+	<div class="actions">
+		<button onclick="window.location.reload()" class="success ui button hide u2f_error_5">{{.i18n.Tr "u2f_reload"}}</button>
+		<div class="ui cancel button">{{.i18n.Tr "cancel"}}</div>
+	</div>
+</div>

templates/user/settings/security.tmpl

@@ -4,6 +4,7 @@
 	<div class="ui container">
 		{{template "base/alert" .}}
 		{{template "user/settings/security_twofa" .}}
+		{{template "user/settings/security_u2f" .}}
 		{{template "user/settings/security_accountlinks" .}}
 		{{if .EnableOpenIDSignIn}}
 		{{template "user/settings/security_openid" .}}

templates/user/settings/security_openid.tmpl

@@ -43,7 +43,7 @@
 		{{.CsrfTokenHtml}}
 		<div class="required field {{if .Err_OpenID}}error{{end}}">
 			<label for="openid">{{.i18n.Tr "settings.add_new_openid"}}</label>
-			<input id="openid" name="openid" type="text" autofocus required>
+			<input id="openid" name="openid" type="text" required>
 		</div>
 		<button class="ui green button">
 			{{.i18n.Tr "settings.add_openid"}}

templates/user/settings/security_u2f.tmpl

@@ -0,0 +1,56 @@
+<h4 class="ui top attached header">
+{{.i18n.Tr "settings.u2f"}}
+</h4>
+<div class="ui attached segment">
+	<p>{{.i18n.Tr "settings.u2f_desc" | Str2html}}</p>
+	{{if .TwofaEnrolled}}
+		<div class="ui key list">
+			{{range .U2FRegistrations}}
+			    <div class="item">
+			    	<div class="right floated content">
+			    		<button class="ui red tiny button delete-button" id="delete-registration" data-url="{{$.Link}}/u2f/delete" data-id="{{.ID}}">
+			    		{{$.i18n.Tr "settings.delete_key"}}
+			    		</button>
+			    	</div>
+			    	<div class="content">
+			    		<strong>{{.Name}}</strong>
+			    	</div>
+			    </div>
+			{{end}}
+		</div>
+		<div class="ui form">
+			{{.CsrfTokenHtml}}
+			<div class="required field">
+				<label for="nickname">{{.i18n.Tr "settings.u2f_nickname"}}</label>
+				<input id="nickname" name="nickname" type="text" required>
+			</div>
+			<button id="register-security-key" class="positive ui labeled icon button"><i class="usb icon"></i>{{.i18n.Tr "settings.u2f_register_key"}}</button>
+		</div>
+	{{else}}
+		<b>{{.i18n.Tr "settings.u2f_require_twofa"}}</b>
+	{{end}}
+</div>
+
+<div class="ui small modal" id="register-device">
+	<div class="header">{{.i18n.Tr "settings.u2f_register_key"}}</div>
+	<div class="content">
+		<i class="notched spinner loading icon"></i> {{.i18n.Tr "settings.u2f_press_button"}}
+	</div>
+	<div class="actions">
+		<div class="ui cancel button">{{.i18n.Tr "cancel"}}</div>
+	</div>
+</div>
+
+{{template "user/auth/u2f_error" .}}
+
+<div class="ui small basic delete modal" id="delete-registration">
+	<div class="ui icon header">
+		<i class="trash icon"></i>
+	{{.i18n.Tr "settings.u2f_delete_key"}}
+	</div>
+	<div class="content">
+		<p>{{.i18n.Tr "settings.u2f_delete_key_desc"}}</p>
+	</div>
+	{{template "base/delete_modal_actions" .}}
+</div>
+

vendor/github.com/tstranex/u2f/LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2015 The Go FIDO U2F Library Authors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

vendor/github.com/tstranex/u2f/README.md

@@ -0,0 +1,97 @@
+# Go FIDO U2F Library
+
+This Go package implements the parts of the FIDO U2F specification required on
+the server side of an application.
+
+[![Build Status](https://travis-ci.org/tstranex/u2f.svg?branch=master)](https://travis-ci.org/tstranex/u2f)
+
+## Features
+
+- Native Go implementation
+- No dependancies other than the Go standard library
+- Token attestation certificate verification
+
+## Usage
+
+Please visit http://godoc.org/github.com/tstranex/u2f for the full
+documentation.
+
+### How to enrol a new token
+
+```go
+app_id := "http://localhost"
+
+// Send registration request to the browser.
+c, _ := NewChallenge(app_id, []string{app_id})
+req, _ := c.RegisterRequest()
+
+// Read response from the browser.
+var resp RegisterResponse
+reg, err := Register(resp, c, nil)
+if err != nil {
+    // Registration failed.
+}
+
+// Store registration in the database.
+```
+
+### How to perform an authentication
+
+```go
+// Fetch registration and counter from the database.
+var reg Registration
+var counter uint32
+
+// Send authentication request to the browser.
+c, _ := NewChallenge(app_id, []string{app_id})
+req, _ := c.SignRequest(reg)
+
+// Read response from the browser.
+var resp SignResponse
+newCounter, err := reg.Authenticate(resp, c, counter)
+if err != nil {
+    // Authentication failed.
+}
+
+// Store updated counter in the database.
+```
+
+## Installation
+
+```
+$ go get github.com/tstranex/u2f
+```
+
+## Example
+
+See u2fdemo/main.go for an full example server. To run it:
+
+```
+$ go install github.com/tstranex/u2f/u2fdemo
+$ ./bin/u2fdemo
+```
+
+Open https://localhost:3483 in Chrome.
+Ignore the SSL warning (due to the self-signed certificate for localhost).
+You can then test registering and authenticating using your token.
+
+## Changelog
+
+- 2016-12-18: The package has been updated to work with the new
+  U2F Javascript 1.1 API specification. This causes some breaking changes.
+
+  `SignRequest` has been replaced by `WebSignRequest` which now includes
+  multiple registrations. This is useful when the user has multiple devices
+  registered since you can now authenticate against any of them with a single
+  request.
+
+  `WebRegisterRequest` has been introduced, which should generally be used
+  instead of using `RegisterRequest` directly. It includes the list of existing
+  registrations with the new registration request. If the user's device already
+  matches one of the existing registrations, it will refuse to re-register.
+
+  `Challenge.RegisterRequest` has been replaced by `NewWebRegisterRequest`.
+
+## License
+
+The Go FIDO U2F Library is licensed under the MIT License.

vendor/github.com/tstranex/u2f/auth.go

@@ -0,0 +1,136 @@
+// Go FIDO U2F Library
+// Copyright 2015 The Go FIDO U2F Library Authors. All rights reserved.
+// Use of this source code is governed by the MIT
+// license that can be found in the LICENSE file.
+
+package u2f
+
+import (
+	"crypto/ecdsa"
+	"crypto/sha256"
+	"encoding/asn1"
+	"errors"
+	"math/big"
+	"time"
+)
+
+// SignRequest creates a request to initiate an authentication.
+func (c *Challenge) SignRequest(regs []Registration) *WebSignRequest {
+	var sr WebSignRequest
+	sr.AppID = c.AppID
+	sr.Challenge = encodeBase64(c.Challenge)
+	for _, r := range regs {
+		rk := getRegisteredKey(c.AppID, r)
+		sr.RegisteredKeys = append(sr.RegisteredKeys, rk)
+	}
+	return &sr
+}
+
+// ErrCounterTooLow is raised when the counter value received from the device is
+// lower than last stored counter value. This may indicate that the device has
+// been cloned (or is malfunctioning). The application may choose to disable
+// the particular device as precaution.
+var ErrCounterTooLow = errors.New("u2f: counter too low")
+
+// Authenticate validates a SignResponse authentication response.
+// An error is returned if any part of the response fails to validate.
+// The counter should be the counter associated with appropriate device
+// (i.e. resp.KeyHandle).
+// The latest counter value is returned, which the caller should store.
+func (reg *Registration) Authenticate(resp SignResponse, c Challenge, counter uint32) (newCounter uint32, err error) {
+	if time.Now().Sub(c.Timestamp) > timeout {
+		return 0, errors.New("u2f: challenge has expired")
+	}
+	if resp.KeyHandle != encodeBase64(reg.KeyHandle) {
+		return 0, errors.New("u2f: wrong key handle")
+	}
+
+	sigData, err := decodeBase64(resp.SignatureData)
+	if err != nil {
+		return 0, err
+	}
+
+	clientData, err := decodeBase64(resp.ClientData)
+	if err != nil {
+		return 0, err
+	}
+
+	ar, err := parseSignResponse(sigData)
+	if err != nil {
+		return 0, err
+	}
+
+	if ar.Counter < counter {
+		return 0, ErrCounterTooLow
+	}
+
+	if err := verifyClientData(clientData, c); err != nil {
+		return 0, err
+	}
+
+	if err := verifyAuthSignature(*ar, &reg.PubKey, c.AppID, clientData); err != nil {
+		return 0, err
+	}
+
+	if !ar.UserPresenceVerified {
+		return 0, errors.New("u2f: user was not present")
+	}
+
+	return ar.Counter, nil
+}
+
+type ecdsaSig struct {
+	R, S *big.Int
+}
+
+type authResp struct {
+	UserPresenceVerified bool
+	Counter              uint32
+	sig                  ecdsaSig
+	raw                  []byte
+}
+
+func parseSignResponse(sd []byte) (*authResp, error) {
+	if len(sd) < 5 {
+		return nil, errors.New("u2f: data is too short")
+	}
+
+	var ar authResp
+
+	userPresence := sd[0]
+	if userPresence|1 != 1 {
+		return nil, errors.New("u2f: invalid user presence byte")
+	}
+	ar.UserPresenceVerified = userPresence == 1
+
+	ar.Counter = uint32(sd[1])<<24 | uint32(sd[2])<<16 | uint32(sd[3])<<8 | uint32(sd[4])
+
+	ar.raw = sd[:5]
+
+	rest, err := asn1.Unmarshal(sd[5:], &ar.sig)
+	if err != nil {
+		return nil, err
+	}
+	if len(rest) != 0 {
+		return nil, errors.New("u2f: trailing data")
+	}
+
+	return &ar, nil
+}
+
+func verifyAuthSignature(ar authResp, pubKey *ecdsa.PublicKey, appID string, clientData []byte) error {
+	appParam := sha256.Sum256([]byte(appID))
+	challenge := sha256.Sum256(clientData)
+
+	var buf []byte
+	buf = append(buf, appParam[:]...)
+	buf = append(buf, ar.raw...)
+	buf = append(buf, challenge[:]...)
+	hash := sha256.Sum256(buf)
+
+	if !ecdsa.Verify(pubKey, hash[:], ar.sig.R, ar.sig.S) {
+		return errors.New("u2f: invalid signature")
+	}
+
+	return nil
+}

vendor/github.com/tstranex/u2f/certs.go

@@ -0,0 +1,89 @@
+// Go FIDO U2F Library
+// Copyright 2015 The Go FIDO U2F Library Authors. All rights reserved.
+// Use of this source code is governed by the MIT
+// license that can be found in the LICENSE file.
+
+package u2f
+
+import (
+	"crypto/x509"
+	"log"
+)
+
+const plugUpCert = `-----BEGIN CERTIFICATE-----