[PATCH 3.2 81/87] crypto: algif_skcipher - Fix race condition in skcipher_check_key
From: Ben Hutchings <hidden>
Date: 2016-02-09 00:11:45
Also in:
lkml
3.2.77-rc1 review patch. If anyone has any objections, please let me know. ------------------ 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. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Ben Hutchings <redacted> --- crypto/algif_skcipher.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c@@ -551,22 +551,23 @@ static struct proto_ops algif_skcipher_o 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;
@@ -580,6 +581,8 @@ static int skcipher_check_key(struct soc unlock: release_sock(psk); +unlock_child: + release_sock(sk); return err; }