[PATCH net 10/14] can: dev: can_put_echo_skb(): free skb on invalid echo index

[Marc Kleine-Budde <mkl@pengutronix.de>]

From: Cunhao Lu <1579567540@qq.com>

can_put_echo_skb() consumes the skb on all paths except when the echo
index is out of bounds. This leaves ownership with the caller on -EINVAL,
unlike the other error paths, and can leak the skb if the caller expects
consistent semantics.

Free the skb before returning -EINVAL so that all return paths consume it.

Fixes: 6411959c10fe ("can: dev: can_put_echo_skb(): don't crash kernel if can_priv::echo_skb is accessed out of bounds")
Cc: stable@vger.kernel.org
Reviewed-by: Vincent Mailhol <mailhol@kernel.org>
Signed-off-by: Cunhao Lu <1579567540@qq.com>
Link: https://patch.msgid.link/tencent_683AA16E643DE00211CD2FB62991264DC605@qq.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/dev/skb.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/can/dev/skb.c b/drivers/net/can/dev/skb.c
index c7be21ed70dd..faafb1033d42 100644
--- a/drivers/net/can/dev/skb.c
+++ b/drivers/net/can/dev/skb.c
@@ -55,6 +55,7 @@ int can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
 	if (idx >= priv->echo_skb_max) {
 		netdev_err(dev, "%s: BUG! Trying to access can_priv::echo_skb out of bounds (%u/max %u)\n",
 			   __func__, idx, priv->echo_skb_max);
+		dev_kfree_skb_any(skb);
 		return -EINVAL;
 	}
 
-- 
2.53.0