1 files changed, 15 insertions, 4 deletions
diff --git a/app/controllers/concerns/project_unauthorized.rb b/app/controllers/concerns/project_unauthorized.rb
index f59440dbc59..d42363b8b17 100644
--- a/app/controllers/concerns/project_unauthorized.rb
+++ b/app/controllers/concerns/project_unauthorized.rb
@@ -1,10 +1,21 @@
 # frozen_string_literal: true
 
 module ProjectUnauthorized
-  extend ActiveSupport::Concern
-
-  # EE would override this
   def project_unauthorized_proc
-    # no-op
+    lambda do |project|
+      if project
+        label = project.external_authorization_classification_label
+        rejection_reason = nil
+
+        unless ::Gitlab::ExternalAuthorization.access_allowed?(current_user, label)
+          rejection_reason = ::Gitlab::ExternalAuthorization.rejection_reason(current_user, label)
+          rejection_reason ||= _('External authorization denied access to this project')
+        end
+
+        if rejection_reason
+          access_denied!(rejection_reason)
+        end
+      end
+    end
   end
 end