node_access_acquire_grants(NULL) gives ACCESS to ALL NODES.

This affects both drupal 5.x and 6.x

If $node IS NULL, and i call node_access_acquire_grants($node) it writes line array('realm' => 'all', 'gid' => 0, 'grant_view' => 1, 'grant_update' => 0, 'grant_delete' => 0); into node_access table.

Solution: node_access_acquire_grants() should check if $node is not NULL!

Background:
I found out this by debugging a site where node_access_rebuild() wrote row 0,0,all,1,0,0 into node_access (beside the normal Taxonomy_access values).

The cause of it was some corruptions in my database:
Description:
"SELECT nid from node" returns array where nid=4 exists.
node_load(4) return NULL. (Because of this node_access_rebuild writes 0,0,all,1,0,0 line into node_access table).

This whole trouble is casued by a corruption between table node_revisions and table node.
In table node: for nid=4, there is a value of vid=1232, BUT this vid DOES NOT EXIST IN "node_revisions" table!
(Vid stands for version_id)