From: Sasha Levin <sasha.levin@xxxxxxxxxx> 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. Backport to v3.0: There have similar codes in key.c in v3.0, so backported this patch. commit id: a3a8784454692dd72e5d5d34dcdab17b4420e74c Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx> Signed-off-by: David Howells <dhowells@xxxxxxxxxx> Cc: Jiri Slaby <jslaby@xxxxxxx> Signed-off-by: Lee, Chun-Yi <jlee@xxxxxxxx> --- security/keys/gc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) Index: linux2/security/keys/key.c =================================================================== --- linux2.orig/security/keys/key.c +++ linux2/security/keys/key.c @@ -639,12 +639,12 @@ found_dead_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 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html