Add captcha if there are multiple failed login attempts

Add method to store session ids by ip

Add new specs for storing session ids

Add cleaning up records after login

Add retrieving anonymous sessions

Add login recaptcha setting

Add new setting to sessions controller

Add conditions for showing captcha

Add sessions controller specs

Add admin settings specs for login protection

Add new settings to api

Add stub to devise spec

Add new translation key

Add cr remarks

Rename class call

Add cr remarks

Change if-clause for consistency

Add cr remarks

Add code review remarks

Refactor AnonymousSession class

Add changelog entry

Move AnonymousSession class to lib

Move store unauthenticated sessions to sessions controller

Move link to recaptcha info

Regenerate text file

Improve copy on the spam page

Change action filter for storing anonymous sessions

Fix rubocop offences

Add code review remarks

Fix schema

Update schema version

7 files changed, 62 insertions, 10 deletions

diff --git a/app/controllers/sessions_controller.rb b/app/controllers/sessions_controller.rb
index a841859621e..d5c63c4e495 100644
--- a/app/controllers/sessions_controller.rb
+++ b/app/controllers/sessions_controller.rb
@@ -21,13 +21,18 @@ class SessionsController < Devise::SessionsController
   prepend_before_action :ensure_password_authentication_enabled!, if: :password_based_login?, only: [:create]
 
   before_action :auto_sign_in_with_provider, only: [:new]
+  before_action :store_unauthenticated_sessions, only: [:new]
+  before_action :save_failed_login, if: :action_new_and_failed_login?
   before_action :load_recaptcha
 
-  after_action :log_failed_login, only: [:new], if: :failed_login?
+  after_action :log_failed_login, if: :action_new_and_failed_login?
+
+  helper_method :captcha_enabled?, :captcha_on_login_required?
 
   helper_method :captcha_enabled?
 
   CAPTCHA_HEADER = 'X-GitLab-Show-Login-Captcha'.freeze
+  MAX_FAILED_LOGIN_ATTEMPTS = 5
 
   def new
     set_minimum_password_length
@@ -71,10 +76,14 @@ class SessionsController < Devise::SessionsController
     request.headers[CAPTCHA_HEADER] && Gitlab::Recaptcha.enabled?
   end
 
+  def captcha_on_login_required?
+    Gitlab::Recaptcha.enabled_on_login? && unverified_anonymous_user?
+  end
+
   # From https://github.com/plataformatec/devise/wiki/How-To:-Use-Recaptcha-with-Devise#devisepasswordscontroller
   def check_captcha
     return unless user_params[:password].present?
-    return unless captcha_enabled?
+    return unless captcha_enabled? || captcha_on_login_required?
     return unless Gitlab::Recaptcha.load_configurations!
 
     if verify_recaptcha
@@ -116,10 +125,28 @@ class SessionsController < Devise::SessionsController
     Gitlab::AppLogger.info("Failed Login: username=#{user_params[:login]} ip=#{request.remote_ip}")
   end
 
+  def action_new_and_failed_login?
+    action_name == 'new' && failed_login?
+  end
+
+  def save_failed_login
+    session[:failed_login_attempts] ||= 0
+    session[:failed_login_attempts] += 1
+  end
+
   def failed_login?
     (options = request.env["warden.options"]) && options[:action] == "unauthenticated"
   end
 
+  # storing sessions per IP lets us check if there are associated multiple
+  # anonymous sessions with one IP and prevent situations when there are
+  # multiple attempts of logging in
+  def store_unauthenticated_sessions
+    return if current_user
+
+    Gitlab::AnonymousSession.new(request.remote_ip, session_id: request.session.id).store_session_id_per_ip
+  end
+
   # Handle an "initial setup" state, where there's only one user, it's an admin,
   # and they require a password change.
   # rubocop: disable CodeReuse/ActiveRecord
@@ -230,6 +257,18 @@ class SessionsController < Devise::SessionsController
     @ldap_servers ||= Gitlab::Auth::LDAP::Config.available_servers
   end
 
+  def unverified_anonymous_user?
+    exceeded_failed_login_attempts? || exceeded_anonymous_sessions?
+  end
+
+  def exceeded_failed_login_attempts?
+    session.fetch(:failed_login_attempts, 0) > MAX_FAILED_LOGIN_ATTEMPTS
+  end
+
+  def exceeded_anonymous_sessions?
+    Gitlab::AnonymousSession.new(request.remote_ip).stored_sessions >= MAX_FAILED_LOGIN_ATTEMPTS
+  end
+
   def authentication_method
     if user_params[:otp_attempt]
       "two-factor"
diff --git a/app/helpers/application_settings_helper.rb b/app/helpers/application_settings_helper.rb
index 91466c13a8f..24236b55e0f 100644
--- a/app/helpers/application_settings_helper.rb
+++ b/app/helpers/application_settings_helper.rb
@@ -232,6 +232,7 @@ module ApplicationSettingsHelper
       :recaptcha_enabled,
       :recaptcha_private_key,
       :recaptcha_site_key,
+      :login_recaptcha_protection_enabled,
       :receive_max_input_size,
       :repository_checks_enabled,
       :repository_storages,
diff --git a/app/models/application_setting.rb b/app/models/application_setting.rb
index d00d0b728f0..6aadbbc9d03 100644
--- a/app/models/application_setting.rb
+++ b/app/models/application_setting.rb
@@ -75,11 +75,11 @@ class ApplicationSetting < ApplicationRecord
 
   validates :recaptcha_site_key,
             presence: true,
-            if: :recaptcha_enabled
+            if: :recaptcha_or_login_protection_enabled
 
   validates :recaptcha_private_key,
             presence: true,
-            if: :recaptcha_enabled
+            if: :recaptcha_or_login_protection_enabled
 
   validates :akismet_api_key,
             presence: true,
@@ -298,4 +298,8 @@ class ApplicationSetting < ApplicationRecord
   def self.cache_backend
     Gitlab::ThreadMemoryCache.cache_backend
   end
+
+  def recaptcha_or_login_protection_enabled
+    recaptcha_enabled || login_recaptcha_protection_enabled
+  end
 end
diff --git a/app/models/application_setting_implementation.rb b/app/models/application_setting_implementation.rb
index 83546bb2a78..17ed3f3688d 100644
--- a/app/models/application_setting_implementation.rb
+++ b/app/models/application_setting_implementation.rb
@@ -67,6 +67,7 @@ module ApplicationSettingImplementation
         project_export_enabled: true,
         protected_ci_variables: false,
         recaptcha_enabled: false,
+        login_recaptcha_protection_enabled: false,
         repository_checks_enabled: true,
         repository_storages: ['default'],
         require_two_factor_authentication: false,
diff --git a/app/views/admin/application_settings/_spam.html.haml b/app/views/admin/application_settings/_spam.html.haml
index d24e46b2815..f0a19075115 100644
--- a/app/views/admin/application_settings/_spam.html.haml
+++ b/app/views/admin/application_settings/_spam.html.haml
@@ -7,11 +7,15 @@
         = f.check_box :recaptcha_enabled, class: 'form-check-input'
         = f.label :recaptcha_enabled, class: 'form-check-label' do
           Enable reCAPTCHA
-        - recaptcha_v2_link_url = 'https://developers.google.com/recaptcha/docs/versions'
-        - recaptcha_v2_link_start = '<a href="%{url}" target="_blank" rel="noopener noreferrer">'.html_safe % { url: recaptcha_v2_link_url }
         %span.form-text.text-muted#recaptcha_help_block
-          = _('Helps prevent bots from creating accounts. We currently only support %{recaptcha_v2_link_start}reCAPTCHA v2%{recaptcha_v2_link_end}').html_safe % { recaptcha_v2_link_start: recaptcha_v2_link_start, recaptcha_v2_link_end: '</a>'.html_safe }
-
+          = _('Helps prevent bots from creating accounts.')
+    .form-group
+      .form-check
+        = f.check_box :login_recaptcha_protection_enabled, class: 'form-check-input'
+        = f.label :login_recaptcha_protection_enabled, class: 'form-check-label' do
+          Enable reCAPTCHA for login
+        %span.form-text.text-muted#recaptcha_help_block
+          = _('Helps prevent bots from brute-force attacks.')
     .form-group
       = f.label :recaptcha_site_key, 'reCAPTCHA Site Key', class: 'label-bold'
       = f.text_field :recaptcha_site_key, class: 'form-control'
@@ -21,6 +25,7 @@
 
     .form-group
       = f.label :recaptcha_private_key, 'reCAPTCHA Private Key', class: 'label-bold'
+    .form-group
       = f.text_field :recaptcha_private_key, class: 'form-control'
 
     .form-group
diff --git a/app/views/admin/application_settings/reporting.html.haml b/app/views/admin/application_settings/reporting.html.haml
index 46e3d1c4570..c60e44b3864 100644
--- a/app/views/admin/application_settings/reporting.html.haml
+++ b/app/views/admin/application_settings/reporting.html.haml
@@ -9,7 +9,9 @@
     %button.btn.btn-default.js-settings-toggle{ type: 'button' }
       = expanded_by_default? ? _('Collapse') : _('Expand')
     %p
-      = _('Enable reCAPTCHA or Akismet and set IP limits.')
+      - recaptcha_v2_link_url = 'https://developers.google.com/recaptcha/docs/versions'
+      - recaptcha_v2_link_start = '<a href="%{url}" target="_blank" rel="noopener noreferrer">'.html_safe % { url: recaptcha_v2_link_url }
+      = _('Enable reCAPTCHA or Akismet and set IP limits. For reCAPTCHA, we currently only support %{recaptcha_v2_link_start}v2%{recaptcha_v2_link_end}').html_safe % { recaptcha_v2_link_start: recaptcha_v2_link_start, recaptcha_v2_link_end: '</a>'.html_safe }
   .settings-content
     = render 'spam'
 
diff --git a/app/views/devise/sessions/_new_base.html.haml b/app/views/devise/sessions/_new_base.html.haml
index 2f10f08c839..6382849de9c 100644
--- a/app/views/devise/sessions/_new_base.html.haml
+++ b/app/views/devise/sessions/_new_base.html.haml
@@ -13,7 +13,7 @@
       .float-right.forgot-password
         = link_to "Forgot your password?", new_password_path(:user)
     %div
-    - if captcha_enabled?
+    - if captcha_enabled? || captcha_on_login_required?
       = recaptcha_tags
 
   .submit-container.move-submit-down