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| author | Sasha Levin <sasha.levin@oracle.com> | 2014-12-29 09:39:01 -0500 |
|---|---|---|
| committer | David Howells <dhowells@redhat.com> | 2015-01-05 15:58:01 +0000 |
| commit | a3a8784454692dd72e5d5d34dcdab17b4420e74c (patch) | |
| tree | be2da54315f410323cc2fca04f63da30cbd2147d | |
| parent | 693a30b8f19a964087a3762d09fb2e1cbad6b0d4 (diff) | |
| download | linux-stable-a3a8784454692dd72e5d5d34dcdab17b4420e74c.tar.gz linux-stable-a3a8784454692dd72e5d5d34dcdab17b4420e74c.tar.bz2 linux-stable-a3a8784454692dd72e5d5d34dcdab17b4420e74c.zip | |
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.
Fixes CVE-2014-9529.
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
| -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 9609a7f0faea..c7952375ac53 100644 --- a/security/keys/gc.c +++ b/security/keys/gc.c @@ -148,12 +148,12 @@ static noinline void key_gc_unused_keys(struct list_head *keys) 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 |