Disable administrative doorkeeper routes (#29187)

config/initializers/doorkeeper.rb

@@ -21,9 +21,14 @@ Doorkeeper.configure do
     user unless user&.otp_required_for_login?
   end
 
-  # If you want to restrict access to the web interface for adding oauth authorized applications, you need to declare the block below.
+  # Doorkeeper provides some administrative interfaces for managing OAuth
+  # Applications, allowing creation, edit, and deletion of applications from the
+  # server. At present, these administrative routes are not integrated into
+  # Mastodon, and as such, we've disabled them by always return a 403 forbidden
+  # response for them. This does not affect the ability for users to manage
+  # their own OAuth Applications.
   admin_authenticator do
-    current_user&.admin? || redirect_to(new_user_session_url)
+    head 403
   end
 
   # Authorization Code expiration time (default 10 minutes).

spec/requests/disabled_oauth_endpoints_spec.rb

+# frozen_string_literal: true
+
+require 'rails_helper'
+
+describe 'Disabled OAuth routes' do
+  # These routes are disabled via the doorkeeper configuration for
+  # `admin_authenticator`, as these routes should only be accessible by server
+  # administrators. For now, these routes are not properly designed and
+  # integrated into Mastodon, so we're disabling them completely
+  describe 'GET /oauth/applications' do
+    it 'returns 403 forbidden' do
+      get oauth_applications_path
+
+      expect(response).to have_http_status(403)
+    end
+  end
+
+  describe 'POST /oauth/applications' do
+    it 'returns 403 forbidden' do
+      post oauth_applications_path
+
+      expect(response).to have_http_status(403)
+    end
+  end
+
+  describe 'GET /oauth/applications/new' do
+    it 'returns 403 forbidden' do
+      get new_oauth_application_path
+
+      expect(response).to have_http_status(403)
+    end
+  end
+
+  describe 'GET /oauth/applications/:id' do
+    let(:application) { Fabricate(:application, scopes: 'read') }
+
+    it 'returns 403 forbidden' do
+      get oauth_application_path(application)
+
+      expect(response).to have_http_status(403)
+    end
+  end
+
+  describe 'PATCH /oauth/applications/:id' do
+    let(:application) { Fabricate(:application, scopes: 'read') }
+
+    it 'returns 403 forbidden' do
+      patch oauth_application_path(application)
+
+      expect(response).to have_http_status(403)
+    end
+  end
+
+  describe 'PUT /oauth/applications/:id' do
+    let(:application) { Fabricate(:application, scopes: 'read') }
+
+    it 'returns 403 forbidden' do
+      put oauth_application_path(application)
+
+      expect(response).to have_http_status(403)
+    end
+  end
+
+  describe 'DELETE /oauth/applications/:id' do
+    let(:application) { Fabricate(:application, scopes: 'read') }
+
+    it 'returns 403 forbidden' do
+      delete oauth_application_path(application)
+
+      expect(response).to have_http_status(403)
+    end
+  end
+
+  describe 'GET /oauth/applications/:id/edit' do
+    let(:application) { Fabricate(:application, scopes: 'read') }
+
+    it 'returns 403 forbidden' do
+      get edit_oauth_application_path(application)
+
+      expect(response).to have_http_status(403)
+    end
+  end
+end