From: Herbert Xu <herbert@gondor.apana.org.au>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: "David S. Miller" <davem@davemloft.net>,
linux-crypto@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
syzkaller <syzkaller@googlegroups.com>,
Kostya Serebryany <kcc@google.com>,
Alexander Potapenko <glider@google.com>,
Sasha Levin <sasha.levin@oracle.com>,
Eric Dumazet <edumazet@google.com>
Subject: [PATCH 4/4] crypto: af_alg - Forbid bind(2) when nokey child sockets are present
Date: Wed, 13 Jan 2016 15:03:32 +0800 [thread overview]
Message-ID: <20160113070332.GD8169@gondor.apana.org.au> (raw)
In-Reply-To: <20160113070106.GC8169@gondor.apana.org.au>
This patch forbids the calling of bind(2) when there are child
sockets created by accept(2) in existence, even if they are created
on the nokey path.
This is needed as those child sockets have references to the tfm
object which bind(2) will destroy.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index e7cb836..f5e18c2 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -130,19 +130,16 @@ EXPORT_SYMBOL_GPL(af_alg_release);
void af_alg_release_parent(struct sock *sk)
{
struct alg_sock *ask = alg_sk(sk);
- bool last;
+ unsigned int nokey = ask->nokey_refcnt;
+ bool last = nokey && !ask->refcnt;
sk = ask->parent;
-
- if (ask->nokey_refcnt && !ask->refcnt) {
- sock_put(sk);
- return;
- }
-
ask = alg_sk(sk);
lock_sock(sk);
- last = !--ask->refcnt;
+ ask->nokey_refcnt -= nokey;
+ if (!last)
+ last = !--ask->refcnt;
release_sock(sk);
if (last)
@@ -188,7 +185,7 @@ static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
err = -EBUSY;
lock_sock(sk);
- if (ask->refcnt)
+ if (ask->refcnt | ask->nokey_refcnt)
goto unlock;
swap(ask->type, type);
@@ -306,6 +303,7 @@ int af_alg_accept(struct sock *sk, struct socket *newsock)
if (nokey || !ask->refcnt++)
sock_hold(sk);
+ ask->nokey_refcnt += nokey;
alg_sk(sk2)->parent = sk;
alg_sk(sk2)->type = type;
alg_sk(sk2)->nokey_refcnt = nokey;
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
next prev parent reply other threads:[~2016-01-13 7:03 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-12 18:31 crypto: use-after-free in hash_sock_destruct_common Dmitry Vyukov
2016-01-13 6:57 ` Herbert Xu
2016-01-13 6:59 ` crypto: af_alg - Allow af_af_alg_release_parent to be called on nokey path Herbert Xu
2016-01-13 7:00 ` [PATCH 2/4] crypto: algif_hash - Remove custom release parent function Herbert Xu
2016-01-13 7:01 ` [PATCH 3/4] crypto: algif_skcipher " Herbert Xu
2016-01-13 7:03 ` Herbert Xu [this message]
[not found] ` <CACT4Y+YOiaC1px6SD2hTAGwSd4i8GsTm59uQ+ux1U8EzdoQfPA@mail.gmail.com>
2016-01-13 10:27 ` crypto: use-after-free in hash_sock_destruct_common Dmitry Vyukov
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