crypto: algif_hash - Fix race condition in hash_check_key
We need to lock the child socket in hash_check_key as otherwise
two simultaneous calls can cause the parent socket to be freed.
Cc: stable@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c
index 3653ab6..608a756 100644
--- a/crypto/algif_hash.c
+++ b/crypto/algif_hash.c
@@ -242,22 +242,23 @@
static int hash_check_key(struct socket *sock)
{
- int err;
+ int err = 0;
struct sock *psk;
struct alg_sock *pask;
struct algif_hash_tfm *tfm;
struct sock *sk = sock->sk;
struct alg_sock *ask = alg_sk(sk);
+ lock_sock(sk);
if (ask->refcnt)
- return 0;
+ goto unlock_child;
psk = ask->parent;
pask = alg_sk(ask->parent);
tfm = pask->private;
err = -ENOKEY;
- lock_sock(psk);
+ lock_sock_nested(psk, SINGLE_DEPTH_NESTING);
if (!tfm->has_key)
goto unlock;
@@ -271,6 +272,8 @@
unlock:
release_sock(psk);
+unlock_child:
+ release_sock(sk);
return err;
}