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

1 files changed, 41 insertions, 3 deletions

diff --git a/app/controllers/sessions_controller.rb b/app/controllers/sessions_controller.rb
index 1880bead3ee..7b682cc0cc5 100644
--- a/app/controllers/sessions_controller.rb
+++ b/app/controllers/sessions_controller.rb
@@ -21,10 +21,13 @@ class SessionsController < Devise::SessionsController
   prepend_before_action :ensure_password_authentication_enabled!, if: -> { action_name == 'create' && password_based_login? }
 
   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, if: -> { action_name == 'new' && failed_login? }
-  helper_method :captcha_enabled?
+  after_action :log_failed_login, if: :action_new_and_failed_login?
+
+  helper_method :captcha_enabled?, :captcha_on_login_required?
 
   # protect_from_forgery is already prepended in ApplicationController but
   # authenticate_with_two_factor which signs in the user is prepended before
@@ -38,6 +41,7 @@ class SessionsController < Devise::SessionsController
   protect_from_forgery with: :exception, prepend: true
 
   CAPTCHA_HEADER = 'X-GitLab-Show-Login-Captcha'.freeze
+  MAX_FAILED_LOGIN_ATTEMPTS = 5
 
   def new
     set_minimum_password_length
@@ -81,10 +85,14 @@ 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
@@ -126,10 +134,28 @@ 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
@@ -240,6 +266,18 @@ 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"