Fix authentication before 2FA challenge (#11943)

Regression from #11831

app/controllers/auth/sessions_controller.rb

@@ -8,6 +8,8 @@ class Auth::SessionsController < Devise::SessionsController
   skip_before_action :require_no_authentication, only: [:create]
   skip_before_action :require_functional!
 
+  prepend_before_action :authenticate_with_two_factor, if: :two_factor_enabled?, only: [:create]
+
   before_action :set_instance_presenter, only: [:new]
   before_action :set_body_classes
 
@@ -20,22 +22,9 @@ class Auth::SessionsController < Devise::SessionsController
   end
 
   def create
-    self.resource = begin
-      if user_params[:email].blank? && session[:otp_user_id].present?
-        User.find(session[:otp_user_id])
-      else
-        warden.authenticate!(auth_options)
-      end
-    end
-
-    if resource.otp_required_for_login?
-      if user_params[:otp_attempt].present? && session[:otp_user_id].present?
-        authenticate_with_two_factor_via_otp(resource)
-      else
-        prompt_for_two_factor(resource)
-      end
-    else
-      authenticate_and_respond(resource)
+    super do |resource|
+      remember_me(resource)
+      flash.delete(:notice)
     end
   end
 
@@ -49,6 +38,16 @@ class Auth::SessionsController < Devise::SessionsController
 
   protected
 
+  def find_user
+    if session[:otp_user_id]
+      User.find(session[:otp_user_id])
+    else
+      user   = User.authenticate_with_ldap(user_params) if Devise.ldap_authentication
+      user ||= User.authenticate_with_pam(user_params) if Devise.pam_authentication
+      user ||= User.find_for_authentication(email: user_params[:email])
+    end
+  end
+
   def user_params
     params.require(:user).permit(:email, :password, :otp_attempt)
   end
@@ -71,6 +70,10 @@ class Auth::SessionsController < Devise::SessionsController
     super
   end
 
+  def two_factor_enabled?
+    find_user&.otp_required_for_login?
+  end
+
   def valid_otp_attempt?(user)
     user.validate_and_consume_otp!(user_params[:otp_attempt]) ||
       user.invalidate_otp_backup_code!(user_params[:otp_attempt])
@@ -78,10 +81,24 @@ class Auth::SessionsController < Devise::SessionsController
     false
   end
 
+  def authenticate_with_two_factor
+    user = self.resource = find_user
+
+    if user_params[:otp_attempt].present? && session[:otp_user_id]
+      authenticate_with_two_factor_via_otp(user)
+    elsif user.present? && (user.encrypted_password.blank? || user.valid_password?(user_params[:password]))
+      # If encrypted_password is blank, we got the user from LDAP or PAM,
+      # so credentials are already valid
+
+      prompt_for_two_factor(user)
+    end
+  end
+
   def authenticate_with_two_factor_via_otp(user)
     if valid_otp_attempt?(user)
       session.delete(:otp_user_id)
-      authenticate_and_respond(user)
+      remember_me(user)
+      sign_in(user)
     else
       flash.now[:alert] = I18n.t('users.invalid_otp_token')
       prompt_for_two_factor(user)
@@ -90,16 +107,10 @@ class Auth::SessionsController < Devise::SessionsController
 
   def prompt_for_two_factor(user)
     session[:otp_user_id] = user.id
+    @body_classes = 'lighter'
     render :two_factor
   end
 
-  def authenticate_and_respond(user)
-    sign_in(user)
-    remember_me(user)
-
-    respond_with user, location: after_sign_in_path_for(user)
-  end
-
   private
 
   def set_instance_presenter
@@ -112,11 +123,9 @@ class Auth::SessionsController < Devise::SessionsController
 
   def home_paths(resource)
     paths = [about_path]
-
     if single_user_mode? && resource.is_a?(User)
       paths << short_account_path(username: resource.account)
     end
-
     paths
   end