Index: modules/node/node.module
===================================================================
RCS file: /cvs/drupal/drupal/modules/node/node.module,v
retrieving revision 1.1006
diff -u -r1.1006 node.module
--- modules/node/node.module	29 Dec 2008 22:29:44 -0000	1.1006
+++ modules/node/node.module	30 Dec 2008 09:41:21 -0000
@@ -2385,6 +2385,8 @@
  */
 function node_access_acquire_grants($node) {
   $grants = module_invoke_all('node_access_records', $node);
+  // Let modules alter the grants.
+  drupal_alter('node_access_records', $grants);
   if (empty($grants)) {
     $grants[] = array('realm' => 'all', 'gid' => 0, 'grant_view' => 1, 'grant_update' => 0, 'grant_delete' => 0);
   }