From f35d99ecd31b7cea5d64434c41c6f6a52bd867f0 Mon Sep 17 00:00:00 2001 From: Sasha Levin Date: Mon, 29 Dec 2014 14:39:01 -0600 Subject: KEYS: close race between key lookup and freeing 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. Change-Id: I7856b7012d1bb668b15977ed16a4ee5f9c2882de Signed-off-by: Sasha Levin --- security/keys/key.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/security/keys/key.c b/security/keys/key.c index f7f9d93f08d..e1704f66846 100644 --- a/security/keys/key.c +++ b/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 -- cgit v1.2.3