From: Milan Broz Subject: [PATCH 4/4] crypto: algif_skcipher - Fix race condition in skcipher_check_key Date: Fri, 26 Feb 2016 12:44:11 +0100 Message-ID: <1456487051-14652-4-git-send-email-gmazyland@gmail.com> References: <56D0361B.8040301@gmail.com> <1456487051-14652-1-git-send-email-gmazyland@gmail.com> Cc: stable@vger.kernel.org, Herbert Xu To: linux-crypto@vger.kernel.org Return-path: In-Reply-To: <1456487051-14652-1-git-send-email-gmazyland@gmail.com> Sender: stable-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org From: Herbert Xu 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 --- 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