Commit 1758c094 authored Aug 13, 2009 by Oliver Hartkopp Committed by David S. Miller Aug 14, 2009

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: Oliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: Urs Thuermann <urs@isnogud.escape.de>
CC: Michael Olbrich <m.olbrich@pengutronix.de>
CC: Luotao Fu <l.fu@pengutronix.de>
Signed-off-by: David 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;
		}

		/*

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