bugfix: Make sure a persistent NameID is not generated by default when the...

bugfix: Make sure a persistent NameID is not generated by default when the UserID is missing in the state array.

This allowed misconfigured IdPs (i.e. those without both a PersistenNameID authproc filter, a “userid.attribute” configuration option and no “eduPersonPrincipalName” attribute available after running all the authentication processing filters) to generate a persistent NameID based on “null”, effectively giving all users the same identifier.

modules/saml/lib/IdP/SAML2.php

@@ -680,6 +680,7 @@ class sspmod_saml_IdP_SAML2
             if ($attribute === null) {
                 if (!isset($state['UserID'])) {
                     SimpleSAML\Logger::error('Unable to generate NameID. Check the userid.attribute option.');
+                    return null;
                 }
                 $attributeValue = $state['UserID'];
                 $idpEntityId = $idpMetadata->getString('entityid');