From 03f16c5075b22c8902d2af739969e878b0879c94 Mon Sep 17 00:00:00 2001
From: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Date: Wed, 20 Jan 2021 20:41:35 +0900
Subject: [PATCH] can: dev: can_restart: fix use after free bug
After calling netif_rx_ni(skb), dereferencing skb is unsafe.
Especially, the can_frame cf which aliases skb memory is accessed
after the netif_rx_ni() in:
stats->rx_bytes += cf->len;
Reordering the lines solves the issue.
Fixes: 39549eef3587 ("can: CAN Network device driver and Netlink interface")
Link: https://lore.kernel.org/r/20210120114137.200019-2-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
drivers/net/can/dev.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
index 3486704c8a9573..8b1ae023cb218f 100644
--- a/drivers/net/can/dev.c
+++ b/drivers/net/can/dev.c
@@ -592,11 +592,11 @@ static void can_restart(struct net_device *dev)
cf->can_id |= CAN_ERR_RESTARTED;
- netif_rx_ni(skb);
-
stats->rx_packets++;
stats->rx_bytes += cf->len;
+ netif_rx_ni(skb);
+
restart:
netdev_dbg(dev, "restarted\n");
priv->can_stats.restarts++;
--
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