Merge pull request #11436 from open-craft/omar/saml-crawl-fix

Return 404 response from third party auth login when SAML disabled

common/djangoapps/third_party_auth/saml.py

@@ -2,6 +2,8 @@
 Slightly customized python-social-auth backend for SAML 2.0 support
 """
 import logging
+from django.http import Http404
+from django.utils.functional import cached_property
 from social.backends.saml import SAMLAuth, OID_EDU_PERSON_ENTITLEMENT
 from social.exceptions import AuthForbidden, AuthMissingParameter
 
@@ -22,12 +24,6 @@ class SAMLAuthBackend(SAMLAuth):  # pylint: disable=abstract-method
 
     def setting(self, name, default=None):
         """ Get a setting, from SAMLConfiguration """
-        if not hasattr(self, '_config'):
-            from .models import SAMLConfiguration
-            self._config = SAMLConfiguration.current()  # pylint: disable=attribute-defined-outside-init
-        if not self._config.enabled:
-            from django.core.exceptions import ImproperlyConfigured
-            raise ImproperlyConfigured("SAML Authentication is not enabled.")
         try:
             return self._config.get_setting(name)
         except KeyError:
@@ -35,14 +31,18 @@ class SAMLAuthBackend(SAMLAuth):  # pylint: disable=abstract-method
 
     def auth_url(self):
         """
-        Check that the request includes an 'idp' parameter before getting the
+        Check that SAML is enabled and that the request includes an 'idp'
-        URL to which we must redirect in order to authenticate the user.
+        parameter before getting the URL to which we must redirect in order to
+        authenticate the user.
 
+        raise Http404 if SAML authentication is disabled.
         raise AuthMissingParameter if the 'idp' parameter is missing.
-
-        TODO: remove this method once the fix is merged upstream:
-        https://github.com/omab/python-social-auth/pull/821
         """
+        if not self._config.enabled:
+            log.error('SAML authentication is not enabled')
+            raise Http404
+        # TODO: remove this check once the fix is merged upstream:
+        # https://github.com/omab/python-social-auth/pull/821
         if 'idp' not in self.strategy.request_data():
             raise AuthMissingParameter(self, 'idp')
         return super(SAMLAuthBackend, self).auth_url()
@@ -61,3 +61,8 @@ class SAMLAuthBackend(SAMLAuth):  # pylint: disable=abstract-method
                     log.warning(
                         "SAML user from IdP %s rejected due to missing eduPersonEntitlement %s", idp.name, expected)
                     raise AuthForbidden(self)
+
+    @cached_property
+    def _config(self):
+        from .models import SAMLConfiguration
+        return SAMLConfiguration.current()

common/djangoapps/third_party_auth/tests/test_views.py

@@ -143,3 +143,9 @@ class SAMLAuthTest(SAMLTestCase):
         self.enable_saml()
         response = self.client.get(self.LOGIN_URL)
         self.assertEqual(response.status_code, 302)
+
+    def test_login_disabled(self):
+        """ When SAML is not enabled, the login view should return 404 """
+        self.enable_saml(enabled=False)
+        response = self.client.get(self.LOGIN_URL)
+        self.assertEqual(response.status_code, 404)