Avoid #authenticate_user! in #route_not_found

This method, #route_not_found, is executed as the final fallback for
unrecognized routes (as the name might imply.) We want to avoid
`#authenticate_user!` when calling `#route_not_found`;
`#authenticate_user!` can, depending on the request format, return a 401
instead of redirecting to a login page. This opens a subtle security
exploit where anonymous users will receive a 401 response when
attempting to access a private repo, while a recognized user will
receive a 404, exposing the existence of the private, hidden repo.

1 files changed, 18 insertions, 4 deletions

diff --git a/spec/support/controllers/sessionless_auth_controller_shared_examples.rb b/spec/support/controllers/sessionless_auth_controller_shared_examples.rb
index b5149a0fcb1..bc95fcd6b88 100644
--- a/spec/support/controllers/sessionless_auth_controller_shared_examples.rb
+++ b/spec/support/controllers/sessionless_auth_controller_shared_examples.rb
@@ -34,8 +34,15 @@ shared_examples 'authenticates sessionless user' do |path, format, params|
 
   context 'when the personal access token has no api scope', unless: params[:public] do
     it 'does not log the user in' do
-      expect(authentication_metrics)
-        .to increment(:user_unauthenticated_counter)
+      # Several instances of where these specs are shared route the request
+      #   through ApplicationController#route_not_found which does not involve
+      #   the usual auth code from Devise, so does not increment the
+      #   :user_unauthenticated_counter
+      #
+      unless params[:ignore_incrementing]
+        expect(authentication_metrics)
+          .to increment(:user_unauthenticated_counter)
+      end
 
       personal_access_token.update(scopes: [:read_user])
 
@@ -84,8 +91,15 @@ shared_examples 'authenticates sessionless user' do |path, format, params|
   end
 
   it "doesn't log the user in otherwise", unless: params[:public] do
-    expect(authentication_metrics)
-      .to increment(:user_unauthenticated_counter)
+    # Several instances of where these specs are shared route the request
+    #   through ApplicationController#route_not_found which does not involve
+    #   the usual auth code from Devise, so does not increment the
+    #   :user_unauthenticated_counter
+    #
+    unless params[:ignore_incrementing]
+      expect(authentication_metrics)
+        .to increment(:user_unauthenticated_counter)
+    end
 
     get path, params: default_params.merge(private_token: 'token')