eCryptfs: use after free in ecryptfs_release_messaging()

commit db86be3a12d0b6e5c5b51c2ab2a48f06329cb590 upstream.

We're freeing the list iterator so we should be using the _safe()
version of hlist_for_each_entry().

Fixes: 88b4a07e6610 ("[PATCH] eCryptfs: Public key transport mechanism")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/ecryptfs/messaging.c b/fs/ecryptfs/messaging.c
index ab22480..966a31f 100644 (file)
--- a/fs/ecryptfs/messaging.c
+++ b/fs/ecryptfs/messaging.c
@@ -550,17 +550,17 @@ void ecryptfs_release_messaging(void)
                mutex_unlock(&ecryptfs_msg_ctx_lists_mux);
        }
        if (ecryptfs_daemon_hash) {
-               struct hlist_node *elem;
                struct ecryptfs_daemon *daemon;
+               struct hlist_node *elem, *n;
                int i;
 
                mutex_lock(&ecryptfs_daemon_hash_mux);
                for (i = 0; i < (1 << ecryptfs_hash_bits); i++) {
                        int rc;
 
-                       hlist_for_each_entry(daemon, elem,
-                                            &ecryptfs_daemon_hash[i],
-                                            euid_chain) {
+                       hlist_for_each_entry_safe(daemon, elem, n,
+                                                 &ecryptfs_daemon_hash[i],
+                                                 euid_chain) {
                                rc = ecryptfs_exorcise_daemon(daemon);
                                if (rc)
                                        printk(KERN_ERR "%s: Error whilst "