Re: skb_checksum_help

[Patrick McHardy <kaber@trash.net>]

Thomas Graf wrote:

>I CC'ed netdev, this seems more serious than I thought.
>
>Background: David noticed the assertion csum + 2 > offset being trigged
>in skb_checksum_help. I sent him a patch converting it into a warning
>printing offset, len, n.raw, tail, csum, features and the whole packet
>as hexdump. He uses the acenic driver which is actually capable of doing
>IP checksumming. (Patch enclosed at the end)
>
How does the backtrace look ?

>>skb hdr corrupted!
>>
>
The check looks bogus:

>+		if (skb->h.raw < skb->data || skb->h.raw > skb->data)
>+			printk(KERN_CRIT "skb hdr corrupted!\n");
>+		goto out;
>+	}
>
Regards
Patrick