[PATCH 6.0 085/157] can: af_can: fix NULL pointer dereference in can_rcv_filter

Greg Kroah-Hartman
2022-12-12T13:42:17Z

From: Oliver Hartkopp <socketcan@hartkopp.net>

commit 0acc442309a0a1b01bcdaa135e56e6398a49439c upstream.

Analogue to commit 8aa59e355949 ("can: af_can: fix NULL pointer
dereference in can_rx_register()") we need to check for a missing
initialization of ml_priv in the receive path of CAN frames.

Since commit 4e096a18867a ("net: introduce CAN specific pointer in the
struct net_device") the check for dev->type to be ARPHRD_CAN is not
sufficient anymore since bonding or tun netdevices claim to be CAN
devices but do not initialize ml_priv accordingly.

Fixes: 4e096a18867a ("net: introduce CAN specific pointer in the struct net_device")
Reported-by: syzbot+2d7f58292cb5b29eb5ad@syzkaller.appspotmail.com
Reported-by: Wei Chen <harperchen1110@gmail.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/all/20221206201259.3028-1-socketcan@hartkopp.net
Cc: stable@vger.kernel.org
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/can/af_can.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/can/af_can.c
+++ b/net/can/af_can.c
@@ -680,7 +680,7 @@ static int can_rcv(struct sk_buff *skb,
{
struct canfd_frame *cfd = (struct canfd_frame *)skb->data;

- if (unlikely(dev->type != ARPHRD_CAN || skb->len != CAN_MTU)) {
+ if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || skb->len != CAN_MTU)) {
pr_warn_once("PF_CAN: dropped non conform CAN skbuff: dev type %d, len %d\n",
dev->type, skb->len);
goto free_skb;
@@ -706,7 +706,7 @@ static int canfd_rcv(struct sk_buff *skb
{
struct canfd_frame *cfd = (struct canfd_frame *)skb->data;

- if (unlikely(dev->type != ARPHRD_CAN || skb->len != CANFD_MTU)) {
+ if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || skb->len != CANFD_MTU)) {
pr_warn_once("PF_CAN: dropped non conform CAN FD skbuff: dev type %d, len %d\n",
dev->type, skb->len);
goto free_skb;