Commit 8326fa8ec22f770a900bfe869e7ced22fd42f3e8
Committed by
Greg Kroah-Hartman
1 parent
101e595b88
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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Showing 1 changed file with 2 additions and 2 deletions Side-by-side Diff
security/keys/gc.c
... | ... | @@ -148,11 +148,11 @@ |
148 | 148 | if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) |
149 | 149 | atomic_dec(&key->user->nikeys); |
150 | 150 | |
151 | - key_user_put(key->user); | |
152 | - | |
153 | 151 | /* now throw away the key memory */ |
154 | 152 | if (key->type->destroy) |
155 | 153 | key->type->destroy(key); |
154 | + | |
155 | + key_user_put(key->user); | |
156 | 156 | |
157 | 157 | kfree(key->description); |
158 | 158 |