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authorHerbert Xu <herbert@gondor.apana.org.au>2016-01-15 22:01:08 +0800
committerHerbert Xu <herbert@gondor.apana.org.au>2016-01-18 18:16:34 +0800
commitad46d7e33219218605ea619e32553daf4f346b9f (patch)
tree41d1566160c2dc875fab29865a8988e0fae4d05b /crypto
parentcbafd643be4c01d9df994175d5e2fa8b3b1b86bb (diff)
downloadlinux-ad46d7e33219218605ea619e32553daf4f346b9f.tar.gz
crypto: algif_hash - Fix race condition in hash_check_key
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>
Diffstat (limited to 'crypto')
-rw-r--r--crypto/algif_hash.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c
index 3653ab60ec79..608a7562839d 100644
--- a/crypto/algif_hash.c
+++ b/crypto/algif_hash.c
@@ -242,22 +242,23 @@ 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;
 
@@ -271,6 +272,8 @@ static int hash_check_key(struct socket *sock)
 
 unlock:
 	release_sock(psk);
+unlock_child:
+	release_sock(sk);
 
 	return err;
 }