Backup codes for 2fa auth (#1237).

Patch by Felix Schäfer.


git-svn-id: http://svn.redmine.org/redmine/trunk@19990 e93f8b46-1217-0410-a6f0-8f06a7374b81

lib/redmine/twofa/base.rb

@@ -42,7 +42,7 @@ module Redmine
       end
 
       def confirm_pairing!(code)
-        # make sure an otp is used
+        # make sure an otp and not a backup code is used
         if verify_otp!(code)
           @user.update!(twofa_scheme: scheme_name)
           deliver_twofa_paired
@@ -77,6 +77,7 @@ module Redmine
 
       def destroy_pairing_without_verify!
         @user.update!(twofa_scheme: nil)
+        backup_codes.delete_all
         deliver_twofa_unpaired
       end
 
@@ -98,13 +99,58 @@ module Redmine
       end
 
       def verify!(code)
-        verify_otp!(code)
+        verify_otp!(code) || verify_backup_code!(code)
       end
 
       def verify_otp!(code)
         raise 'not implemented'
       end
 
+      def verify_backup_code!(code)
+        # backup codes are case-insensitive and white-space-insensitive
+        code = code.to_s.remove(/[[:space:]]/).downcase
+        user_from_code = Token.find_active_user('twofa_backup_code', code)
+        # invalidate backup code after usage
+        Token.where(user_id: @user.id).find_token('twofa_backup_code', code).try(:delete)
+        # make sure the user using the backup code is the same it's been issued to
+        return false unless @user.present? && @user == user_from_code
+        Mailer.security_notification(
+          @user,
+          User.current,
+          {
+            originator: @user,
+            title: :label_my_account,
+            message: 'twofa_mail_body_backup_code_used',
+            url: { controller: 'my', action: 'account' }
+          }
+        ).deliver
+        return true
+      end
+
+      def init_backup_codes!
+        backup_codes.delete_all
+        tokens = []
+        10.times do
+          token = Token.create(user_id: @user.id, action: 'twofa_backup_code')
+          token.update_columns value: Redmine::Utils.random_hex(6)
+          tokens << token
+        end
+        Mailer.security_notification(
+          @user,
+          User.current,
+          {
+            title: :label_my_account,
+            message: 'twofa_mail_body_backup_codes_generated',
+            url: { controller: 'my', action: 'account' }
+          }
+        ).deliver
+        tokens
+      end
+
+      def backup_codes
+        Token.where(user_id: @user.id, action: 'twofa_backup_code')
+      end
+
       # this will only be used on pairing initialization
       def init_pairing_view_variables
         otp_confirm_view_variables