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From:   Ziyang Xuan <william.xuanziyang@huawei.com>
To:     <max@enpas.org>, <wg@grandegger.com>, <mkl@pengutronix.de>,
        <davem@davemloft.net>, <edumazet@google.com>, <kuba@kernel.org>,
        <pabeni@redhat.com>, <linux-can@vger.kernel.org>,
        <netdev@vger.kernel.org>
CC:     <linux-kernel@vger.kernel.org>
Subject: [PATCH] can: can327: fix potential skb leak when netdev is down
Date:   Thu, 10 Nov 2022 14:14:37 +0800
Message-ID: <20221110061437.411525-1-william.xuanziyang@huawei.com>
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In can327_feed_frame_to_netdev(), it did not free the skb when netdev
is down, and all callers of can327_feed_frame_to_netdev() did not free
allocated skb too. That would trigger skb leak.

Fix it by adding kfree_skb() in can327_feed_frame_to_netdev() when netdev
is down. Not tested, just compiled.

Fixes: 43da2f07622f ("can: can327: CAN/ldisc driver for ELM327 based OBD-II adapters")
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
---
 drivers/net/can/can327.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/can327.c b/drivers/net/can/can327.c
index 0aa1af31d0fe..17bca63f3dd3 100644
--- a/drivers/net/can/can327.c
+++ b/drivers/net/can/can327.c
@@ -263,8 +263,10 @@ static void can327_feed_frame_to_netdev(struct can327 *elm, struct sk_buff *skb)
 {
 	lockdep_assert_held(&elm->lock);
 
-	if (!netif_running(elm->dev))
+	if (!netif_running(elm->dev)) {
+		kfree_skb(skb);
 		return;
+	}
 
 	/* Queue for NAPI pickup.
 	 * rx-offload will update stats and LEDs for us.
-- 
2.25.1