| From | Luis Henriques <> | Subject | [PATCH 3.16.y-ckt 051/129] crypto: algif_hash - Fix race condition in hash_check_key | Date | Fri, 26 Feb 2016 10:20:22 +0000 |
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3.16.7-ckt25 -stable review patch. If anyone has any objections, please let me know.
---8<------------------------------------------------------------
From: Herbert Xu <herbert@gondor.apana.org.au>
commit ad46d7e33219218605ea619e32553daf4f346b9f upstream.
We need to lock the child socket in hash_check_key as otherwise two simultaneous calls can cause the parent socket to be freed.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- 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 287e3fe08428..2dfb0f10e0bb 100644 --- a/crypto/algif_hash.c +++ b/crypto/algif_hash.c @@ -253,22 +253,23 @@ 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; @@ -282,6 +283,8 @@ static int hash_check_key(struct socket *sock) unlock: release_sock(psk); +unlock_child: + release_sock(sk); return err; }
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