[systemd-devel] [PATCH 09/12] policy: kdbus_policy_set() use another variable to save entries

[Djalal Harouni]

In kdbus_policy_set() function, we use the 'e' variable to reference
each entry of the 'db->entries_hash', so at the end the variable 'e' will
for sure point to a valid one.

Next in the KDBUS_ITEMS_FOREACH() iterator and if we fail at the first
KDBUS_ITEM_VALID() test, we jmp to exit:

Which contains the following:
if (e)
	kdbus_policy_entry_free(e);

Here 'e' points to a valid entry and it will be freed, so even we
restore all the other entries from that list, there will be always one
missing, the last one pointed by that 'e' variable.

To fix this, just use another 'tmp_entry' variable to reference hash
entries.

Signed-off-by: Djalal Harouni <tixxdz at opendz.org>
---
 policy.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/policy.c b/policy.c
index 9cf7f67..601d2a8 100644
--- a/policy.c
+++ b/policy.c
@@ -467,6 +467,7 @@ int kdbus_policy_set(struct kdbus_policy_db *db,
 		     const void *owner)
 {
 	struct kdbus_policy_db_entry *e = NULL;
+	struct kdbus_policy_db_entry *tmp_entry = NULL;
 	struct kdbus_policy_db_entry_access *a;
 	const struct kdbus_item *item;
 	struct hlist_node *tmp;
@@ -483,8 +484,8 @@ int kdbus_policy_set(struct kdbus_policy_db *db,
 	 * At the same time, the lookup mechanism won't find any collisions
 	 * when looking for already exising names.
 	 */
-	hash_for_each_safe(db->entries_hash, i, tmp, e, hentry)
-		if (e->owner == owner) {
+	hash_for_each_safe(db->entries_hash, i, tmp, tmp_entry, hentry)
+		if (tmp_entry->owner == owner) {
 			struct kdbus_policy_list_entry *l;
 
 			l = kzalloc(sizeof(*l), GFP_KERNEL);
@@ -493,9 +494,9 @@ int kdbus_policy_set(struct kdbus_policy_db *db,
 				goto exit;
 			}
 
-			l->e = e;
+			l->e = tmp_entry;
 			list_add_tail(&l->entry, &list);
-			hash_del(&e->hentry);
+			hash_del(&tmp_entry->hentry);
 		}
 
 	/* Walk the list of items and look for new policies */
-- 
1.9.0