[PATCH 4/4] crypto: algif_skcipher - Fix race condition in skcipher_check_key
From: Milan Broz <hidden>
Date: 2016-02-26 11:44:27
Also in:
stable
Subsystem:
crypto api, the rest · Maintainers:
Herbert Xu, "David S. Miller", Linus Torvalds
From: Herbert Xu <herbert@gondor.apana.org.au>
commit 1822793a523e5d5730b19cc21160ff1717421bc8 upstream.
We need to lock the child socket in skcipher_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 [off-list ref]
---
crypto/algif_skcipher.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 83bcf75..c0f0356 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c@@ -757,22 +757,23 @@ static struct proto_ops algif_skcipher_ops = { static int skcipher_check_key(struct socket *sock) { - int err; + int err = 0; struct sock *psk; struct alg_sock *pask; struct skcipher_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;
@@ -786,6 +787,8 @@ static int skcipher_check_key(struct socket *sock) unlock: release_sock(psk); +unlock_child: + release_sock(sk); return err; }
--
2.7.0