Implement authentication (login) using a U2F device.

- Move the `authenticate_with_two_factor` method from
  `ApplicationController` to the `AuthenticatesWithTwoFactor` module,
  where it should be.

app/assets/javascripts/u2f/authenticate.js.coffee

+# Authenticate U2F (universal 2nd factor) devices for users to authenticate with.
+#
+# State Flow #1: setup -> in_progress -> authenticated -> POST to server
+# State Flow #2: setup -> in_progress -> error -> setup
+
+class @U2FAuthenticate
+  constructor: (@container, u2fParams) ->
+    @appId = u2fParams.app_id
+    @challenges = u2fParams.challenges
+    @signRequests = u2fParams.sign_requests
+
+  start: () =>
+    if U2FUtil.isU2FSupported()
+      @renderSetup()
+    else
+      @renderNotSupported()
+
+  authenticate: () =>
+    u2f.sign(@appId, @challenges, @signRequests, (response) =>
+      if response.errorCode
+        error = new U2FError(response.errorCode)
+        @renderError(error);
+      else
+        @renderAuthenticated(JSON.stringify(response))
+    , 10)
+
+  #############
+  # Rendering #
+  #############
+
+  templates: {
+    "notSupported": "#js-authenticate-u2f-not-supported",
+    "setup": '#js-authenticate-u2f-setup',
+    "inProgress": '#js-authenticate-u2f-in-progress',
+    "error": '#js-authenticate-u2f-error',
+    "authenticated": '#js-authenticate-u2f-authenticated'
+  }
+
+  renderTemplate: (name, params) =>
+    templateString = $(@templates[name]).html()
+    template = _.template(templateString)
+    @container.html(template(params))
+
+  renderSetup: () =>
+    @renderTemplate('setup')
+    @container.find('#js-login-u2f-device').on('click', @renderInProgress)
+
+  renderInProgress: () =>
+    @renderTemplate('inProgress')
+    @authenticate()
+
+  renderError: (error) =>
+    @renderTemplate('error', {error_message: error.message()})
+    @container.find('#js-u2f-try-again').on('click', @renderSetup)
+
+  renderAuthenticated: (deviceResponse) =>
+    @renderTemplate('authenticated')
+    # Prefer to do this instead of interpolating using Underscore templates
+    # because of JSON escaping issues.
+    @container.find("#js-device-response").val(deviceResponse)
+
+  renderNotSupported: () =>
+    @renderTemplate('notSupported')

app/controllers/concerns/authenticates_with_two_factor.rb

@@ -24,7 +24,64 @@ module AuthenticatesWithTwoFactor
   # Returns nil
   def prompt_for_two_factor(user)
     session[:otp_user_id] = user.id
+    setup_u2f_authentication(user)
+    render 'devise/sessions/two_factor'
+  end
+
+  def authenticate_with_two_factor
+    user = self.resource = find_user
+
+    if user_params[:otp_attempt].present? && session[:otp_user_id]
+      authenticate_with_two_factor_via_otp(user)
+    elsif user_params[:device_response].present? && session[:otp_user_id]
+      authenticate_with_two_factor_via_u2f(user)
+    elsif user && user.valid_password?(user_params[:password])
+      prompt_for_two_factor(user)
+    end
+  end
+
+  private
+
+  def authenticate_with_two_factor_via_otp(user)
+    if valid_otp_attempt?(user)
+      # Remove any lingering user data from login
+      session.delete(:otp_user_id)
+
+      remember_me(user) if user_params[:remember_me] == '1'
+      sign_in(user)
+    else
+      flash.now[:alert] = 'Invalid two-factor code.'
+      render :two_factor
+    end
+  end
+
+  # Authenticate using the response from a U2F (universal 2nd factor) device
+  def authenticate_with_two_factor_via_u2f(user)
+    if U2fRegistration.authenticate(user, u2f_app_id, user_params[:device_response], session[:challenges])
+      # Remove any lingering user data from login
+      session.delete(:otp_user_id)
+      session.delete(:challenges)
+
+      sign_in(user)
+    else
+      flash.now[:alert] = 'Authentication via U2F device failed.'
+      prompt_for_two_factor(user)
+    end
+  end
 
-    render 'devise/sessions/two_factor' and return
+  # Setup in preparation of communication with a U2F (universal 2nd factor) device
+  # Actual communication is performed using a Javascript API
+  def setup_u2f_authentication(user)
+    key_handles = user.u2f_registrations.pluck(:key_handle)
+    u2f = U2F::U2F.new(u2f_app_id)
+
+    if key_handles.present?
+      sign_requests = u2f.authentication_requests(key_handles)
+      challenges = sign_requests.map(&:challenge)
+      session[:challenges] = challenges
+      gon.push(u2f: { challenges: challenges, app_id: u2f_app_id,
+                      sign_requests: sign_requests,
+                      browser_supports_u2f: browser_supports_u2f? })
+    end
   end
 end

app/controllers/sessions_controller.rb

@@ -54,7 +54,7 @@ class SessionsController < Devise::SessionsController
   end
 
   def user_params
-    params.require(:user).permit(:login, :password, :remember_me, :otp_attempt)
+    params.require(:user).permit(:login, :password, :remember_me, :otp_attempt, :device_response)
   end
 
   def find_user
@@ -89,27 +89,6 @@ class SessionsController < Devise::SessionsController
     find_user.try(:two_factor_enabled?)
   end
 
-  def authenticate_with_two_factor
-    user = self.resource = find_user
-
-    if user_params[:otp_attempt].present? && session[:otp_user_id]
-      if valid_otp_attempt?(user)
-        # Remove any lingering user data from login
-        session.delete(:otp_user_id)
-
-        remember_me(user) if user_params[:remember_me] == '1'
-        sign_in(user) and return
-      else
-        flash.now[:alert] = 'Invalid two-factor code.'
-        render :two_factor and return
-      end
-    else
-      if user && user.valid_password?(user_params[:password])
-        prompt_for_two_factor(user)
-      end
-    end
-  end
-
   def auto_sign_in_with_provider
     provider = Gitlab.config.omniauth.auto_sign_in_with_provider
     return unless provider.present?

app/views/devise/sessions/two_factor.html.haml

 %div
   .login-box
     .login-heading
-      %h3 Two-factor Authentication
+      %h3 Two-Factor Authentication
     .login-body
+      - if @user.two_factor_otp_enabled?
+        %h5 Authenticate via Two-Factor App
         = form_for(resource, as: resource_name, url: session_path(resource_name), method: :post) do |f|
           = f.hidden_field :remember_me, value: params[resource_name][:remember_me]
-        = f.text_field :otp_attempt, class: 'form-control', placeholder: 'Two-factor Authentication code', required: true, autofocus: true, autocomplete: 'off'
+          = f.text_field :otp_attempt, class: 'form-control', placeholder: 'Two-Factor Authentication code', required: true, autofocus: true, autocomplete: 'off'
           %p.help-block.hint Enter the code from the two-factor app on your mobile device. If you've lost your device, you may enter one of your recovery codes.
           .prepend-top-20
             = f.submit "Verify code", class: "btn btn-save"
+
+      - if @user.two_factor_u2f_enabled?
+
+        %hr
+        = render "u2f/authenticate"

app/views/u2f/_authenticate.html.haml

+#js-authenticate-u2f
+
+%script#js-authenticate-u2f-not-supported{ type: "text/template" }
+  %p Your browser doesn't support U2F. Please use Google Chrome desktop (version 41 or newer).
+
+%script#js-authenticate-u2f-setup{ type: "text/template" }
+  %div
+    %p Insert your security key (if you haven't already), and press the button below.
+    %a.btn.btn-info#js-login-u2f-device{ href: 'javascript:void(0)' } Login Via U2F Device
+
+%script#js-authenticate-u2f-in-progress{ type: "text/template" }
+  %p Trying to communicate with your device. Plug it in (if you haven't already) and press the button on the device now.
+
+%script#js-authenticate-u2f-error{ type: "text/template" }
+  %div
+    %p <%= error_message %>
+    %a.btn.btn-warning#js-u2f-try-again Try again?
+
+%script#js-authenticate-u2f-authenticated{ type: "text/template" }
+  %div
+    %p We heard back from your U2F device. Click this button to authenticate with the GitLab server.
+    = form_tag(new_user_session_path, method: :post) do |f|
+      = hidden_field_tag 'user[device_response]', nil, class: 'form-control', required: true, id: "js-device-response"
+      = submit_tag "Authenticate via U2F Device", class: "btn btn-success"
+
+:javascript
+  var u2fAuthenticate = new U2FAuthenticate($("#js-authenticate-u2f"), gon.u2f);
+  u2fAuthenticate.start();

spec/features/login_spec.rb

@@ -33,11 +33,11 @@ feature 'Login', feature: true do
 
       before do
         login_with(user, remember: true)
-        expect(page).to have_content('Two-factor Authentication')
+        expect(page).to have_content('Two-Factor Authentication')
       end
 
       def enter_code(code)
-        fill_in 'Two-factor Authentication code', with: code
+        fill_in 'Two-Factor Authentication code', with: code
         click_button 'Verify code'
       end
 
@@ -143,12 +143,12 @@ feature 'Login', feature: true do
 
       context 'within the grace period' do
         it 'redirects to two-factor configuration page' do
-          expect(current_path).to eq new_profile_two_factor_auth_path
-          expect(page).to have_content('You must enable Two-factor Authentication for your account before')
+          expect(current_path).to eq profile_two_factor_auth_path
+          expect(page).to have_content('You must enable Two-Factor Authentication for your account before')
         end
 
-        it 'disallows skipping two-factor configuration' do
-          expect(current_path).to eq new_profile_two_factor_auth_path
+        it 'allows skipping two-factor configuration', js: true do
+          expect(current_path).to eq profile_two_factor_auth_path
 
           click_link 'Configure it later'
           expect(current_path).to eq root_path
@@ -159,26 +159,26 @@ feature 'Login', feature: true do
         let(:user) { create(:user, otp_grace_period_started_at: 9999.hours.ago) }
 
         it 'redirects to two-factor configuration page' do
-          expect(current_path).to eq new_profile_two_factor_auth_path
-          expect(page).to have_content('You must enable Two-factor Authentication for your account.')
+          expect(current_path).to eq profile_two_factor_auth_path
+          expect(page).to have_content('You must enable Two-Factor Authentication for your account.')
         end
 
-        it 'disallows skipping two-factor configuration' do
-          expect(current_path).to eq new_profile_two_factor_auth_path
+        it 'disallows skipping two-factor configuration', js: true do
+          expect(current_path).to eq profile_two_factor_auth_path
           expect(page).not_to have_link('Configure it later')
         end
       end
     end
 
-    context 'without grace pariod defined' do
+    context 'without grace period defined' do
       before(:each) do
         stub_application_setting(two_factor_grace_period: 0)
         login_with(user)
       end
 
       it 'redirects to two-factor configuration page' do
-        expect(current_path).to eq new_profile_two_factor_auth_path
-        expect(page).to have_content('You must enable Two-factor Authentication for your account.')
+        expect(current_path).to eq profile_two_factor_auth_path
+        expect(page).to have_content('You must enable Two-Factor Authentication for your account.')
       end
     end
   end

spec/javascripts/fixtures/u2f/authenticate.html.haml

+= render partial: "u2f/authenticate", locals: { new_user_session_path: "/users/sign_in" }

spec/javascripts/u2f/authenticate_spec.coffee

+#= require u2f/authenticate
+#= require u2f/util
+#= require u2f/error
+#= require u2f
+#= require ./mock_u2f_device
+
+describe 'U2FAuthenticate', ->
+  U2FUtil.enableTestMode()
+  fixture.load('u2f/authenticate')
+
+  beforeEach ->
+    @u2fDevice = new MockU2FDevice
+    @container = $("#js-authenticate-u2f")
+    @component = new U2FAuthenticate(@container, {}, "token")
+    @component.start()
+
+  it 'allows authenticating via a U2F device', ->
+    setupButton = @container.find("#js-login-u2f-device")
+    setupMessage = @container.find("p")
+    expect(setupMessage.text()).toContain('Insert your security key')
+    expect(setupButton.text()).toBe('Login Via U2F Device')
+    setupButton.trigger('click')
+
+    inProgressMessage = @container.find("p")
+    expect(inProgressMessage.text()).toContain("Trying to communicate with your device")
+
+    @u2fDevice.respondToAuthenticateRequest({deviceData: "this is data from the device"})
+    authenticatedMessage = @container.find("p")
+    deviceResponse = @container.find('#js-device-response')
+    expect(authenticatedMessage.text()).toContain("Click this button to authenticate with the GitLab server")
+    expect(deviceResponse.val()).toBe('{"deviceData":"this is data from the device"}')
+
+  describe "errors", ->
+    it "displays an error message", ->
+      setupButton = @container.find("#js-login-u2f-device")
+      setupButton.trigger('click')
+      @u2fDevice.respondToAuthenticateRequest({errorCode: "error!"})
+      errorMessage = @container.find("p")
+      expect(errorMessage.text()).toContain("There was a problem communicating with your device")
+
+    it "allows retrying authentication after an error", ->
+      setupButton = @container.find("#js-login-u2f-device")
+      setupButton.trigger('click')
+      @u2fDevice.respondToAuthenticateRequest({errorCode: "error!"})
+      retryButton = @container.find("#js-u2f-try-again")
+      retryButton.trigger('click')
+
+      setupButton = @container.find("#js-login-u2f-device")
+      setupButton.trigger('click')
+      @u2fDevice.respondToAuthenticateRequest({deviceData: "this is data from the device"})
+      authenticatedMessage = @container.find("p")
+      expect(authenticatedMessage.text()).toContain("Click this button to authenticate with the GitLab server")