From 50aca891d7a554db0901b245167cd653d73aaa71 Mon Sep 17 00:00:00 2001
From: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Date: Wed, 20 Jan 2021 20:41:37 +0900
Subject: [PATCH] can: peak_usb: fix use after free bugs
Git-commit: 50aca891d7a554db0901b245167cd653d73aaa71
References: git-fixes
Patch-mainline: v5.11-rc5

After calling peak_usb_netif_rx_ni(skb), dereferencing skb is unsafe.
Especially, the can_frame cf which aliases skb memory is accessed
after the peak_usb_netif_rx_ni().

Reordering the lines solves the issue.

Fixes: 0a25e1f4f185 ("can: peak_usb: add support for PEAK new CANFD USB adapters")
Link: https://lore.kernel.org/r/20210120114137.200019-4-mailhol.vincent@wanadoo.fr
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/net/can/usb/peak_usb/pcan_usb_fd.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/net/can/usb/peak_usb/pcan_usb_fd.c
+++ b/drivers/net/can/usb/peak_usb/pcan_usb_fd.c
@@ -512,11 +512,11 @@ static int pcan_usb_fd_decode_canmsg(str
 	else
 		memcpy(cfd->data, rm->d, cfd->len);
 
-	peak_usb_netif_rx(skb, &usb_if->time_ref, le32_to_cpu(rm->ts_low));
-
 	netdev->stats.rx_packets++;
 	netdev->stats.rx_bytes += cfd->len;
 
+	peak_usb_netif_rx(skb, &usb_if->time_ref, le32_to_cpu(rm->ts_low));
+
 	return 0;
 }
 
@@ -578,11 +578,11 @@ static int pcan_usb_fd_decode_status(str
 	if (!skb)
 		return -ENOMEM;
 
-	peak_usb_netif_rx(skb, &usb_if->time_ref, le32_to_cpu(sm->ts_low));
-
 	netdev->stats.rx_packets++;
 	netdev->stats.rx_bytes += cf->can_dlc;
 
+	peak_usb_netif_rx(skb, &usb_if->time_ref, le32_to_cpu(sm->ts_low));
+
 	return 0;
 }