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crypto: algif_skcipher - Fix race condition in skcipher_check_key

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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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Herbert Xu 2016-01-15 22:02:20 +08:00 • committed by Greg Kroah-Hartman
parent aa51954b30
commit f84d1fcb59
1 changed files with 6 additions and 3 deletions
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9
crypto/algif_skcipher.c
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@ -755,22 +755,23 @@ static struct proto_ops algif_skcipher_ops = {
static int skcipher_check_key(struct socket *sock) static int skcipher_check_key(struct socket *sock)
{ {
int err; int err = 0;
struct sock *psk; struct sock *psk;
struct alg_sock *pask; struct alg_sock *pask;
struct skcipher_tfm *tfm; struct skcipher_tfm *tfm;
struct sock *sk = sock->sk; struct sock *sk = sock->sk;
struct alg_sock *ask = alg_sk(sk); struct alg_sock *ask = alg_sk(sk);
lock_sock(sk);
if (ask->refcnt) if (ask->refcnt)
return 0; goto unlock_child;
psk = ask->parent; psk = ask->parent;
pask = alg_sk(ask->parent); pask = alg_sk(ask->parent);
tfm = pask->private; tfm = pask->private;
err = -ENOKEY; err = -ENOKEY;
lock_sock(psk); lock_sock_nested(psk, SINGLE_DEPTH_NESTING);
if (!tfm->has_key) if (!tfm->has_key)
goto unlock; goto unlock;
@ -784,6 +785,8 @@ static int skcipher_check_key(struct socket *sock)
unlock: unlock:
release_sock(psk); release_sock(psk);
unlock_child:
release_sock(sk);
return err; return err;
} }