From 1758c0947605211ef953cc91d6bbdf847a21b822 Mon Sep 17 00:00:00 2001
From: Oliver Hartkopp <oliver@hartkopp.net>
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 <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>
---
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;
}
/*
--
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