gluster: Fix use after free in glfs_clear_preopened()

This fixes a use-after-free bug introduced in commit 6349c154. We need
to use QLIST_FOREACH_SAFE() when freeing elements in the loop. Spotted
by Coverity.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 1479378608-11962-1-git-send-email-kwolf@redhat.com
Signed-off-by: Jeff Cody <jcody@redhat.com>

diff --git a/block/gluster.c b/block/gluster.c
index 0ce15f7..891c13b 100644 (file)
--- a/block/gluster.c
+++ b/block/gluster.c
@@ -239,12 +239,13 @@ static glfs_t *glfs_find_preopened(const char *volume)
 static void glfs_clear_preopened(glfs_t *fs)
 {
     ListElement *entry = NULL;
+    ListElement *next;
 
     if (fs == NULL) {
         return;
     }
 
-    QLIST_FOREACH(entry, &glfs_list, list) {
+    QLIST_FOREACH_SAFE(entry, &glfs_list, list, next) {
         if (entry->saved.fs == fs) {
             if (--entry->saved.ref) {
                 return;