[added to the 4.1 stable tree] crypto: algif_hash - Fix race condition in hash_check_key
From: Sasha Levin <hidden>
Date: 2016-02-10 15:13:40
Subsystem:
crypto api, the rest · Maintainers:
Herbert Xu, "David S. Miller", Linus Torvalds
From: Herbert Xu <herbert@gondor.apana.org.au> This patch has been added to the 4.1 stable tree. If you have any objections, please let us know. =============== [ Upstream commit ad46d7e33219218605ea619e32553daf4f346b9f ] 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> Signed-off-by: Sasha Levin <redacted> --- crypto/algif_hash.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c
index 1867020..7b5018b 100644
--- a/crypto/algif_hash.c
+++ b/crypto/algif_hash.c@@ -234,22 +234,23 @@ static struct proto_ops algif_hash_ops = { 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;
@@ -263,6 +264,8 @@ static int hash_check_key(struct socket *sock) unlock: release_sock(psk); +unlock_child: + release_sock(sk); return err; }
--
2.5.0