From: Ziyang Xuan <william.xuanziyang@huawei.com>
To: <robin@protonic.nl>
Cc: <linux@rempel-privat.de>, <socketcan@hartkopp.net>,
<mkl@pengutronix.de>, <davem@davemloft.net>, <kuba@kernel.org>,
<linux-can@vger.kernel.org>, <netdev@vger.kernel.org>,
<linux-kernel@vger.kernel.org>
Subject: [PATCH net] can: j1939: fix UAF for rx_kref of j1939_priv
Date: Sun, 26 Sep 2021 18:47:57 +0800 [thread overview]
Message-ID: <20210926104757.2021540-1-william.xuanziyang@huawei.com> (raw)
It will trigger UAF for rx_kref of j1939_priv as following.
cpu0 cpu1
j1939_sk_bind(socket0, ndev0, ...)
j1939_netdev_start
j1939_sk_bind(socket1, ndev0, ...)
j1939_netdev_start
j1939_priv_set
j1939_priv_get_by_ndev_locked
j1939_jsk_add
.....
j1939_netdev_stop
kref_put_lock(&priv->rx_kref, ...)
kref_get(&priv->rx_kref, ...)
REFCOUNT_WARN("addition on 0;...")
====================================================
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 20874 at lib/refcount.c:25 refcount_warn_saturate+0x169/0x1e0
RIP: 0010:refcount_warn_saturate+0x169/0x1e0
Call Trace:
j1939_netdev_start+0x68b/0x920
j1939_sk_bind+0x426/0xeb0
? security_socket_bind+0x83/0xb0
The rx_kref's kref_get() and kref_put() should use j1939_netdev_lock to
protect.
Fixes: 9d71dd0c70099 ("can: add support of SAE J1939 protocol")
Reported-by: syzbot+85d9878b19c94f9019ad@syzkaller.appspotmail.com
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
---
net/can/j1939/main.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c
index 08c8606cfd9c..9bc55ecb37f9 100644
--- a/net/can/j1939/main.c
+++ b/net/can/j1939/main.c
@@ -249,11 +249,14 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev)
struct j1939_priv *priv, *priv_new;
int ret;
- priv = j1939_priv_get_by_ndev(ndev);
+ spin_lock(&j1939_netdev_lock);
+ priv = j1939_priv_get_by_ndev_locked(ndev);
if (priv) {
kref_get(&priv->rx_kref);
+ spin_unlock(&j1939_netdev_lock);
return priv;
}
+ spin_unlock(&j1939_netdev_lock);
priv = j1939_priv_create(ndev);
if (!priv)
@@ -269,10 +272,10 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev)
/* Someone was faster than us, use their priv and roll
* back our's.
*/
+ kref_get(&priv_new->rx_kref);
spin_unlock(&j1939_netdev_lock);
dev_put(ndev);
kfree(priv);
- kref_get(&priv_new->rx_kref);
return priv_new;
}
j1939_priv_set(ndev, priv);
--
2.25.1
next reply other threads:[~2021-09-26 10:49 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-26 10:47 Ziyang Xuan [this message]
2021-10-08 11:34 ` [PATCH net] can: j1939: fix UAF for rx_kref of j1939_priv Oleksij Rempel
2021-10-17 10:43 ` Marc Kleine-Budde
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