1 files changed, 194 insertions, 0 deletions
diff --git a/app/controllers/concerns/verifies_with_email.rb b/app/controllers/concerns/verifies_with_email.rb
new file mode 100644
index 00000000000..1a3e7136481
--- /dev/null
+++ b/app/controllers/concerns/verifies_with_email.rb
@@ -0,0 +1,194 @@
+# frozen_string_literal: true
+
+# == VerifiesWithEmail
+#
+# Controller concern to handle verification by email
+module VerifiesWithEmail
+  extend ActiveSupport::Concern
+  include ActionView::Helpers::DateHelper
+
+  TOKEN_LENGTH = 6
+  TOKEN_VALID_FOR_MINUTES = 60
+
+  included do
+    prepend_before_action :verify_with_email, only: :create, unless: -> { two_factor_enabled? }
+  end
+
+  def verify_with_email
+    return unless user = find_user || find_verification_user
+
+    if session[:verification_user_id] && token = verification_params[:verification_token].presence
+      # The verification token is submitted, verify it
+      verify_token(user, token)
+    elsif require_email_verification_enabled?(user)
+      # Limit the amount of password guesses, since we now display the email verification page
+      # when the password is correct, which could be a giveaway when brute-forced.
+      return render_sign_in_rate_limited if check_rate_limit!(:user_sign_in, scope: user) { true }
+
+      if user.valid_password?(user_params[:password])
+        # The user has logged in successfully.
+        if user.unlock_token
+          # Prompt for the token if it already has been set
+          prompt_for_email_verification(user)
+        elsif user.access_locked? || !AuthenticationEvent.initial_login_or_known_ip_address?(user, request.ip)
+          # require email verification if:
+          # - their account has been locked because of too many failed login attempts, or
+          # - they have logged in before, but never from the current ip address
+          send_verification_instructions(user)
+          prompt_for_email_verification(user)
+        end
+      end
+    end
+  end
+
+  def resend_verification_code
+    return unless user = find_verification_user
+
+    send_verification_instructions(user)
+    prompt_for_email_verification(user)
+  end
+
+  def successful_verification
+    session.delete(:verification_user_id)
+    @redirect_url = after_sign_in_path_for(current_user) # rubocop:disable Gitlab/ModuleWithInstanceVariables
+
+    render layout: 'minimal'
+  end
+
+  private
+
+  def find_verification_user
+    return unless session[:verification_user_id]
+
+    User.find_by_id(session[:verification_user_id])
+  end
+
+  # After successful verification and calling sign_in, devise redirects the
+  # user to this path. Override it to show the successful verified page.
+  def after_sign_in_path_for(resource)
+    if action_name == 'create' && session[:verification_user_id]
+      return users_successful_verification_path
+    end
+
+    super
+  end
+
+  def send_verification_instructions(user)
+    return if send_rate_limited?(user)
+
+    raw_token, encrypted_token = generate_token
+    user.unlock_token = encrypted_token
+    user.lock_access!({ send_instructions: false })
+    send_verification_instructions_email(user, raw_token)
+  end
+
+  def send_verification_instructions_email(user, token)
+    return unless user.can?(:receive_notifications)
+
+    Notify.verification_instructions_email(
+      user.id,
+      token: token,
+      expires_in: TOKEN_VALID_FOR_MINUTES).deliver_later
+
+    log_verification(user, :instructions_sent)
+  end
+
+  def verify_token(user, token)
+    return handle_verification_failure(user, :rate_limited) if verification_rate_limited?(user)
+    return handle_verification_failure(user, :invalid) unless valid_token?(user, token)
+    return handle_verification_failure(user, :expired) if expired_token?(user)
+
+    handle_verification_success(user)
+  end
+
+  def generate_token
+    raw_token = SecureRandom.random_number(10**TOKEN_LENGTH).to_s.rjust(TOKEN_LENGTH, '0')
+    encrypted_token = digest_token(raw_token)
+    [raw_token, encrypted_token]
+  end
+
+  def digest_token(token)
+    Devise.token_generator.digest(User, :unlock_token, token)
+  end
+
+  def render_sign_in_rate_limited
+    message = s_('IdentityVerification|Maximum login attempts exceeded. '\
+      'Wait %{interval} and try again.') % { interval: user_sign_in_interval }
+    redirect_to new_user_session_path, alert: message
+  end
+
+  def user_sign_in_interval
+    interval_in_seconds = Gitlab::ApplicationRateLimiter.rate_limits[:user_sign_in][:interval]
+    distance_of_time_in_words(interval_in_seconds)
+  end
+
+  def verification_rate_limited?(user)
+    Gitlab::ApplicationRateLimiter.throttled?(:email_verification, scope: user.unlock_token)
+  end
+
+  def send_rate_limited?(user)
+    Gitlab::ApplicationRateLimiter.throttled?(:email_verification_code_send, scope: user)
+  end
+
+  def expired_token?(user)
+    user.locked_at < (Time.current - TOKEN_VALID_FOR_MINUTES.minutes)
+  end
+
+  def valid_token?(user, token)
+    user.unlock_token == digest_token(token)
+  end
+
+  def handle_verification_failure(user, reason)
+    message = case reason
+              when :rate_limited
+                s_("IdentityVerification|You've reached the maximum amount of tries. "\
+                   'Wait %{interval} or resend a new code and try again.') % { interval: email_verification_interval }
+              when :expired
+                s_('IdentityVerification|The code has expired. Resend a new code and try again.')
+              when :invalid
+                s_('IdentityVerification|The code is incorrect. Enter it again, or resend a new code.')
+              end
+
+    user.errors.add(:base, message)
+    log_verification(user, :failed_attempt, reason)
+
+    prompt_for_email_verification(user)
+  end
+
+  def email_verification_interval
+    interval_in_seconds = Gitlab::ApplicationRateLimiter.rate_limits[:email_verification][:interval]
+    distance_of_time_in_words(interval_in_seconds)
+  end
+
+  def handle_verification_success(user)
+    user.unlock_access!
+    log_verification(user, :successful)
+
+    sign_in(user)
+  end
+
+  def prompt_for_email_verification(user)
+    session[:verification_user_id] = user.id
+    self.resource = user
+
+    render 'devise/sessions/email_verification'
+  end
+
+  def verification_params
+    params.require(:user).permit(:verification_token)
+  end
+
+  def log_verification(user, event, reason = nil)
+    Gitlab::AppLogger.info(
+      message: 'Email Verification',
+      event: event.to_s.titlecase,
+      username: user.username,
+      ip: request.ip,
+      reason: reason.to_s
+    )
+  end
+
+  def require_email_verification_enabled?(user)
+    Feature.enabled?(:require_email_verification, user)
+  end
+end