From 1758c0947605211ef953cc91d6bbdf847a21b822 Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Thu, 13 Aug 2009 22:54:25 +0000 Subject: [PATCH] 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 Signed-off-by: Urs Thuermann CC: Michael Olbrich CC: Luotao Fu Signed-off-by: David S. Miller --- net/can/af_can.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/net/can/af_can.c b/net/can/af_can.c index e733725b11d4..f9c027be78b2 100644 --- a/net/can/af_can.c +++ b/net/can/af_can.c @@ -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; } /*