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Commit 1758c094 authored by Oliver Hartkopp's avatar Oliver Hartkopp Committed by David S. Miller
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can: Use WARN_ONCE() instead of BUG_ON() for sanity check in receive path 



To ensure a proper handling of CAN frames transported in skbuffs some checks
need to be performed at receive time.

As stated by Michael Olbrich and Luotao Fu BUG_ON() might be to restrictive.
This is right as we can just drop the non conform skbuff and the Kernel can
continue working.

This patch replaces the BUG_ON() with a WARN_ONCE() so that the system remains
healthy but we made the problem visible (once).

Signed-off-by: default avatarOliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: default avatarUrs Thuermann <urs@isnogud.escape.de>
CC: Michael Olbrich <m.olbrich@pengutronix.de>
CC: Luotao Fu <l.fu@pengutronix.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 49d4b8ba

net/can/af_can.c

+13 −5
Original line number Diff line number Diff line
@@ -651,12 +651,16 @@ static int can_rcv(struct sk_buff *skb, struct net_device *dev, 
	struct can_frame *cf = (struct can_frame *)skb->data;

	int matches;



	if (dev->type != ARPHRD_CAN || !net_eq(dev_net(dev), &init_net)) {

		kfree_skb(skb);

		return 0;

	}

	if (!net_eq(dev_net(dev), &init_net))

		goto drop;



	BUG_ON(skb->len != sizeof(struct can_frame) || cf->can_dlc > 8);

	if (WARN_ONCE(dev->type != ARPHRD_CAN ||

		      skb->len != sizeof(struct can_frame) ||

		      cf->can_dlc > 8,

		      "PF_CAN: dropped non conform skbuf: "

		      "dev type %d, len %d, can_dlc %d\n",

		      dev->type, skb->len, cf->can_dlc))

		goto drop;



	/* update statistics */

	can_stats.rx_frames++;
@@ -683,6 +687,10 @@ static int can_rcv(struct sk_buff *skb, struct net_device *dev, 
	}



	return 0;



drop:

	kfree_skb(skb);

	return 0;

}



/*