can: af_can: fix NULL pointer dereference in can_rcv_filter

Analogue to commit 8aa59e3 ("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 4e096a1 ("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: 4e096a1 ("net: introduce CAN specific pointer in the struct net_device")
Reported-by: [email protected]
Reported-by: Wei Chen <[email protected]>
Signed-off-by: Oliver Hartkopp <[email protected]>
Link: https://lore.kernel.org/all/[email protected]
Cc: [email protected]
Signed-off-by: Marc Kleine-Budde <[email protected]>

Author: hartkopp

net/can/af_can.c

@@ -677,7 +677,7 @@ static void can_receive(struct sk_buff *skb, struct net_device *dev)
 static int can_rcv(struct sk_buff *skb, struct net_device *dev,
 		   struct packet_type *pt, struct net_device *orig_dev)
 {
-	if (unlikely(dev->type != ARPHRD_CAN || (!can_is_can_skb(skb)))) {
+	if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_can_skb(skb))) {
 		pr_warn_once("PF_CAN: dropped non conform CAN skbuff: dev type %d, len %d\n",
 			     dev->type, skb->len);
 
@@ -692,7 +692,7 @@ static int can_rcv(struct sk_buff *skb, struct net_device *dev,
 static int canfd_rcv(struct sk_buff *skb, struct net_device *dev,
 		     struct packet_type *pt, struct net_device *orig_dev)
 {
-	if (unlikely(dev->type != ARPHRD_CAN || (!can_is_canfd_skb(skb)))) {
+	if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_canfd_skb(skb))) {
 		pr_warn_once("PF_CAN: dropped non conform CAN FD skbuff: dev type %d, len %d\n",
 			     dev->type, skb->len);
 
@@ -707,7 +707,7 @@ static int canfd_rcv(struct sk_buff *skb, struct net_device *dev,
 static int canxl_rcv(struct sk_buff *skb, struct net_device *dev,
 		     struct packet_type *pt, struct net_device *orig_dev)
 {
-	if (unlikely(dev->type != ARPHRD_CAN || (!can_is_canxl_skb(skb)))) {
+	if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_canxl_skb(skb))) {
 		pr_warn_once("PF_CAN: dropped non conform CAN XL skbuff: dev type %d, len %d\n",
 			     dev->type, skb->len);