Add recovery code support for two-factor auth (#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 #563 and fixes #987

* Set OTP_SECRET in test enviroment

* add missing .html to view file names

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 @@ Rails.application.routes.draw do
     resource :two_factor_auth, only: [:show, :new, :create] do
       member do
         post :disable
+        post :recovery_codes
       end
     end
   end