Add recovery code support for two-factor auth (mastodon#1773)

* Add recovery code support for two-factor auth

When users enable two-factor auth, the app now generates ten
single-use recovery codes. Users are encouraged to print the codes
and store them in a safe place.

The two-factor prompt during login now accepts both OTP codes and
recovery codes.

The two-factor settings UI allows users to regenerated lost
recovery codes. Users who have set up two-factor auth prior to
this feature being added can use it to generate recovery codes
for the first time.

Fixes mastodon#563 and fixes mastodon#987

* Set OTP_SECRET in test enviroment

* add missing .html to view file names

.env.test

@@ -1,3 +1,4 @@
 # Federation
 LOCAL_DOMAIN=cb6e6126.ngrok.io
 LOCAL_HTTPS=true
+OTP_SECRET=100c7faeef00caa29242f6b04156742bf76065771fd4117990c4282b8748ff3d99f8fdae97c982ab5bd2e6756a159121377cce4421f4a8ecd2d67bd7749a3fb4

app/assets/stylesheets/lists.scss

@@ -6,3 +6,12 @@
     margin: 0 5px;
   }
 }
+
+.recovery-codes {
+  column-count: 2;
+  height: 100px;
+  li {
+    list-style: decimal;
+    margin-left: 20px;
+  }
+}

app/controllers/auth/sessions_controller.rb

@@ -49,7 +49,8 @@ def two_factor_enabled?
   end
 
   def valid_otp_attempt?(user)
-    user.validate_and_consume_otp!(user_params[:otp_attempt])
+    user.validate_and_consume_otp!(user_params[:otp_attempt]) ||
+      user.invalidate_otp_backup_code!(user_params[:otp_attempt])
   end
 
   def authenticate_with_two_factor

app/controllers/settings/two_factor_auths_controller.rb

@@ -19,9 +19,9 @@ def new
   def create
     if current_user.validate_and_consume_otp!(confirmation_params[:code])
       current_user.otp_required_for_login = true
+      @codes = current_user.generate_otp_backup_codes!
       current_user.save!
-
-      redirect_to settings_two_factor_auth_path, notice: I18n.t('two_factor_auth.enabled_success')
+      flash[:notice] = I18n.t('two_factor_auth.enabled_success')
     else
       @confirmation = Form::TwoFactorConfirmation.new
       set_qr_code
@@ -30,6 +30,12 @@ def create
     end
   end
 
+  def recovery_codes
+    @codes = current_user.generate_otp_backup_codes!
+    current_user.save!
+    flash[:notice] = I18n.t('two_factor_auth.recovery_codes_regenerated')
+  end
+
   def disable
     current_user.otp_required_for_login = false
     current_user.save!

app/models/user.rb

@@ -5,7 +5,9 @@ class User < ApplicationRecord
 
   devise :registerable, :recoverable,
          :rememberable, :trackable, :validatable, :confirmable,
-         :two_factor_authenticatable, otp_secret_encryption_key: ENV['OTP_SECRET']
+         :two_factor_authenticatable, :two_factor_backupable,
+         otp_secret_encryption_key: ENV['OTP_SECRET'],
+         otp_number_of_backup_codes: 10
 
   belongs_to :account, inverse_of: :user
   accepts_nested_attributes_for :account

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

@@ -2,7 +2,9 @@
   = t('auth.login')
 
 = simple_form_for(resource, as: resource_name, url: session_path(resource_name), method: :post) do |f|
-  = f.input :otp_attempt, type: :number, placeholder: t('simple_form.labels.defaults.otp_attempt'), input_html: { 'aria-label' => t('simple_form.labels.defaults.otp_attempt') }, required: true, autofocus: true, autocomplete: 'off'
+  = f.input :otp_attempt, type: :number, placeholder: t('simple_form.labels.defaults.otp_attempt'),
+      input_html: { 'aria-label' => t('simple_form.labels.defaults.otp_attempt') }, required: true, autofocus: true, autocomplete: 'off',
+      hint: t('simple_form.hints.sessions.otp')
 
   .actions
     = f.button :button, t('auth.login'), type: :submit

app/views/settings/two_factor_auths/_recovery_codes.html.haml

@@ -0,0 +1,7 @@
+%p.hint= t('two_factor_auth.recovery_instructions')
+
+%h3= t('two_factor_auth.recovery_codes')
+%ol.recovery-codes
+  - @codes.each do |code|
+    %li
+      %samp= code

app/views/settings/two_factor_auths/create.html.haml

@@ -0,0 +1,4 @@
+- content_for :page_title do
+  = t('settings.two_factor_auth')
+
+= render 'recovery_codes'

app/views/settings/two_factor_auths/recovery_codes.html.haml

@@ -0,0 +1,4 @@
+- content_for :page_title do
+  = t('settings.two_factor_auth')
+
+= render 'recovery_codes'

app/views/settings/two_factor_auths/show.html.haml

@@ -8,3 +8,8 @@
     = link_to t('two_factor_auth.disable'), disable_settings_two_factor_auth_path, data: { method: 'POST' }, class: 'block-button'
   - else
     = link_to t('two_factor_auth.setup'), new_settings_two_factor_auth_path, class: 'block-button'
+
+- if current_user.otp_required_for_login
+  .simple_form
+    %p.hint= t('two_factor_auth.lost_recovery_codes')
+    = link_to t('two_factor_auth.generate_recovery_codes'), recovery_codes_settings_two_factor_auth_path, data: { method: 'POST' }, class: 'block-button'

config/initializers/devise.rb

@@ -1,6 +1,7 @@
 Devise.setup do |config|
   config.warden do |manager|
     manager.default_strategies(scope: :user).unshift :two_factor_authenticatable
+    manager.default_strategies(scope: :user).unshift :two_factor_backupable
   end
 
   # The secret key used by Devise. Devise uses this key to generate

config/locales/en.yml

@@ -290,8 +290,13 @@ en:
     disable: Disable
     enable: Enable
     enabled_success: Two-factor authentication successfully enabled
+    generate_recovery_codes: Generate Recovery Codes
     instructions_html: "<strong>Scan this QR code into Google Authenticator or a similiar TOTP app on your phone</strong>. From now on, that app will generate tokens that you will have to enter when logging in."
+    lost_recovery_codes: Recovery codes allow you to regain access to your account if you lose your phone. If you've lost your recovery codes, you can regenerate them here. Your old recovery codes will be invalidated.
     manual_instructions: 'If you can''t scan the QR code and need to enter it manually, here is the plain-text secret:'
+    recovery_codes: Recovery Codes
+    recovery_codes_regenerated: Recovery codes successfully regenerated
+    recovery_instructions: If you ever lose access to your phone, you can use one of the recovery codes below to regain access to your account. Keep the recovery codes safe, for example by printing them and storing them with other important documents.
     setup: Set up
     warning: If you cannot configure an authenticator app right now, you should click "disable" or you won't be able to login.
     wrong_code: The entered code was invalid! Are server time and device time correct?

config/locales/simple_form.en.yml

@@ -10,6 +10,8 @@ en:
         note: At most 160 characters
       imports:
         data: CSV file exported from another Mastodon instance
+      sessions:
+        otp: Enter the Two-factor code from your phone or use one of your recovery codes.
     labels:
       defaults:
         avatar: Avatar

config/routes.rb

@@ -64,6 +64,7 @@
     resource :two_factor_auth, only: [:show, :new, :create] do
       member do
         post :disable
+        post :recovery_codes
       end
     end
   end

db/migrate/20170414080609_add_devise_two_factor_backupable_to_users.rb

@@ -0,0 +1,5 @@
+class AddDeviseTwoFactorBackupableToUsers < ActiveRecord::Migration[5.0]
+  def change
+    add_column :users, :otp_backup_codes, :string, array: true
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20170406215816) do
+ActiveRecord::Schema.define(version: 20170414080609) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -313,6 +313,7 @@
     t.integer  "consumed_timestep"
     t.boolean  "otp_required_for_login"
     t.datetime "last_emailed_at"
+    t.string   "otp_backup_codes",                                       array: true
     t.index ["account_id"], name: "index_users_on_account_id", using: :btree
     t.index ["confirmation_token"], name: "index_users_on_confirmation_token", unique: true, using: :btree
     t.index ["email"], name: "index_users_on_email", unique: true, using: :btree

spec/controllers/auth/sessions_controller_spec.rb

@@ -5,7 +5,7 @@
 
   describe 'GET #new' do
     before do
-      request.env["devise.mapping"] = Devise.mappings[:user]
+      request.env['devise.mapping'] = Devise.mappings[:user]
     end
 
     it 'returns http success' do
@@ -15,19 +15,94 @@
   end
 
   describe 'POST #create' do
-    let(:user) { Fabricate(:user, email: 'foo@bar.com', password: 'abcdefgh') }
-
     before do
-      request.env["devise.mapping"] = Devise.mappings[:user]
-      post :create, params: { user: { email: user.email, password: user.password } }
+      request.env['devise.mapping'] = Devise.mappings[:user]
     end
 
-    it 'redirects to home' do
-      expect(response).to redirect_to(root_path)
+    context 'using password authentication' do
+      let(:user) { Fabricate(:user, email: 'foo@bar.com', password: 'abcdefgh') }
+
+      context 'using a valid password' do
+        before do
+          post :create, params: { user: { email: user.email, password: user.password } }
+        end
+
+        it 'redirects to home' do
+          expect(response).to redirect_to(root_path)
+        end
+
+        it 'logs the user in' do
+          expect(controller.current_user).to eq user
+        end
+      end
+
+      context 'using an invalid password' do
+        before do
+          post :create, params: { user: { email: user.email, password: 'wrongpw' } }
+        end
+
+        it 'shows a login error' do
+          expect(flash[:alert]).to match I18n.t('devise.failure.invalid', authentication_keys: 'Email')
+        end
+
+        it "doesn't log the user in" do
+          expect(controller.current_user).to be_nil
+        end
+      end
     end
 
-    it 'logs the user in' do
-      expect(controller.current_user).to eq user
+    context 'using two-factor authentication' do
+      let(:user) do
+        Fabricate(:user, email: 'x@y.com', password: 'abcdefgh',
+                         otp_required_for_login: true, otp_secret: User.generate_otp_secret(32))
+      end
+      let(:recovery_codes) do
+        codes = user.generate_otp_backup_codes!
+        user.save
+        return codes
+      end
+
+      context 'using a valid OTP' do
+        before do
+          post :create, params: { user: { otp_attempt: user.current_otp } }, session: { otp_user_id: user.id }
+        end
+
+        it 'redirects to home' do
+          expect(response).to redirect_to(root_path)
+        end
+
+        it 'logs the user in' do
+          expect(controller.current_user).to eq user
+        end
+      end
+
+      context 'using a valid recovery code' do
+        before do
+          post :create, params: { user: { otp_attempt: recovery_codes.first } }, session: { otp_user_id: user.id }
+        end
+
+        it 'redirects to home' do
+          expect(response).to redirect_to(root_path)
+        end
+
+        it 'logs the user in' do
+          expect(controller.current_user).to eq user
+        end
+      end
+
+      context 'using an invalid OTP' do
+        before do
+          post :create, params: { user: { otp_attempt: 'wrongotp' } }, session: { otp_user_id: user.id }
+        end
+
+        it 'shows a login error' do
+          expect(flash[:alert]).to match I18n.t('users.invalid_otp_token')
+        end
+
+        it "doesn't log the user in" do
+          expect(controller.current_user).to be_nil
+        end
+      end
     end
   end
 end

spec/models/user_spec.rb

@@ -1,6 +1,9 @@
 require 'rails_helper'
+require 'devise_two_factor/spec_helpers'
 
 RSpec.describe User, type: :model do
+  it_behaves_like 'two_factor_backupable'
+
   describe 'validations' do
     it 'is invalid without an account' do
       user = Fabricate.build(:user, account: nil)