diff options
| author | Sasha Levin <sasha.levin@oracle.com> | 2014-12-29 09:39:01 -0500 |
|---|---|---|
| committer | Zefan Li <lizefan@huawei.com> | 2015-04-14 17:33:58 +0800 |
| commit | a42e15a485c14f6d994192af4c16775fbd6c1126 (patch) | |
| tree | 6c5eb91310f957427bb98997e55b1482b79ec0ca /security | |
| parent | 565d34077a24bf7819e8fbbb6c93e4d6271c992f (diff) | |
KEYS: close race between key lookup and freeing
commit a3a8784454692dd72e5d5d34dcdab17b4420e74c upstream.
When a key is being garbage collected, it's key->user would get put before
the ->destroy() callback is called, where the key is removed from it's
respective tracking structures.
This leaves a key hanging in a semi-invalid state which leaves a window open
for a different task to try an access key->user. An example is
find_keyring_by_name() which would dereference key->user for a key that is
in the process of being garbage collected (where key->user was freed but
->destroy() wasn't called yet - so it's still present in the linked list).
This would cause either a panic, or corrupt memory.
Fixes CVE-2014-9529.
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
[lizf: Backported to 3.4: adjust indentation]
Signed-off-by: Zefan Li <lizefan@huawei.com>
Diffstat (limited to 'security')
| -rw-r--r-- | security/keys/gc.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/security/keys/gc.c b/security/keys/gc.c index a42b45531aac..87632bd17b3e 100644 --- a/security/keys/gc.c +++ b/security/keys/gc.c @@ -188,12 +188,12 @@ static noinline void key_gc_unused_key(struct key *key) if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) atomic_dec(&key->user->nikeys); - key_user_put(key->user); - /* now throw away the key memory */ if (key->type->destroy) key->type->destroy(key); + key_user_put(key->user); + kfree(key->description); #ifdef KEY_DEBUGGING |