From: Colin Ian King <colin.king@canonical.com>
Date: Mon, 27 Jul 2015 14:23:43 +0000 (+0100)
Subject: KEYS: ensure we free the assoc array edit if edit is valid
X-Git-Tag: firefly_0821_release~176^2~1350^2
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=ca4da5dd1f99fe9c59f1709fb43e818b18ad20e0;p=firefly-linux-kernel-4.4.55.git

KEYS: ensure we free the assoc array edit if edit is valid

__key_link_end is not freeing the associated array edit structure
and this leads to a 512 byte memory leak each time an identical
existing key is added with add_key().

The reason the add_key() system call returns okay is that
key_create_or_update() calls __key_link_begin() before checking to see
whether it can update a key directly rather than adding/replacing - which
it turns out it can.  Thus __key_link() is not called through
__key_instantiate_and_link() and __key_link_end() must cancel the edit.

CVE-2015-1333

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
---

diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index e72548b5897e..d33437007ad2 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -1181,9 +1181,11 @@ void __key_link_end(struct key *keyring,
 	if (index_key->type == &key_type_keyring)
 		up_write(&keyring_serialise_link_sem);
 
-	if (edit && !edit->dead_leaf) {
-		key_payload_reserve(keyring,
-				    keyring->datalen - KEYQUOTA_LINK_BYTES);
+	if (edit) {
+		if (!edit->dead_leaf) {
+			key_payload_reserve(keyring,
+				keyring->datalen - KEYQUOTA_LINK_BYTES);
+		}
 		assoc_array_cancel_edit(edit);
 	}
 	up_write(&keyring->sem);