[PATCH 2/2] crypto: algif_skcipher - Fix race condition in skcipher_check_key
From: Herbert Xu
Date: Thu Jan 14 2016 - 09:16:25 EST
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@xxxxxxxxxxxxxxxxxxx>
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 39df2a9..5772c0b 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -755,15 +755,16 @@ 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);
@@ -784,6 +785,8 @@ static int skcipher_check_key(struct socket *sock)
unlock:
release_sock(psk);
+unlock_child:
+ release_sock(sk);
return err;
}
--
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt