s4:dsdb Fix linked_attributes to cope with the Feb 2010 changes to DLIST

The DLIST macros changed in behaviour in Feb 2010, and walking the
lists backwards is no longer safe if you don't use the macros.

Andrew Bartlett

diff --git a/source4/dsdb/samdb/ldb_modules/linked_attributes.c b/source4/dsdb/samdb/ldb_modules/linked_attributes.c
index 4f36509a85567e6ce1abb320e0c398e259b7e76b..d2a435ef507d490d7776b6a8832a39b9a615dcf3 100644 (file)
--- a/source4/dsdb/samdb/ldb_modules/linked_attributes.c
+++ b/source4/dsdb/samdb/ldb_modules/linked_attributes.c
@@ -1039,9 +1039,13 @@ static int linked_attributes_prepare_commit(struct ldb_module *module)
        /* walk the list backwards, to do the first entry first, as we
         * added the entries with DLIST_ADD() which puts them at the
         * start of the list */
-       for (ac = la_private->la_list; ac && ac->next; ac=ac->next) ;
 
-       for (; ac; ac=ac->prev) {
+       /* Start at the end of the list - so we can start
+        * there, but ensure we don't create a loop by NULLing
+        * it out in the first element */
+       ac = DLIST_TAIL(la_private->la_list);
+
+       for (; ac; ac=DLIST_PREV(ac)) {
                int ret;
                ac->req = NULL;
                ret = la_do_mod_request(module, ac);