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authorZiyang Xuan <william.xuanziyang@huawei.com>2021-09-26 18:47:57 +0800
committerMarc Kleine-Budde <mkl@pengutronix.de>2021-10-17 14:12:56 +0200
commitd9d52a3ebd284882f5562c88e55991add5d01586 (patch)
tree7258e3bc16fb5a97bb63cf59910890500ad3cd29
parentb504a884f6b5a77dac7d580ffa08e482f70d1a30 (diff)
can: j1939: j1939_netdev_start(): fix UAF for rx_kref of j1939_priv
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") Link: https://lore.kernel.org/all/20210926104757.2021540-1-william.xuanziyang@huawei.com Cc: stable@vger.kernel.org Reported-by: syzbot+85d9878b19c94f9019ad@syzkaller.appspotmail.com Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com> Acked-by: Oleksij Rempel <o.rempel@pengutronix.de> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
-rw-r--r--net/can/j1939/main.c7
1 files 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);