On Thu, Dec 14, 2000 at 11:55:43AM -0800, David S. Miller wrote:
> Date: Thu, 14 Dec 2000 12:07:38 -0800 (PST)
> From: Ion Badulescu <ionut@cs.columbia.edu>
>
> I'm afraid I won't be able to answer this question, since I'm
> leaving for a 3-week vacation in about 50 minutes and I need my
> firewall functional until then. :-) Maybe other people who have
> seen this problem can experiment further.
>
> Ok, regardless I'm very confident netfilter is doing something
> very bad.
>
> Essentially it is feeding SKBs into IPv4 receive processing which
> have a NULL skb->dev, that has always been illegal. Now it OOPSs
> so we can spot such violations.
mmh... After checking some of my assumptions with the code again, I don't
think that netfilter does something wrong.
Referring to some of the other messages in this thread, ip_conntrack seems
to be blamed.
Conntrack is registered at the NF_IP_PRE_ROUTING hook and calls ip_defrag
for all skb's it receives. But we don't touch the dev member of the skb
at all...
Or is there something wrong with:
- packet arrives in net/ipv4/ip_input.c:ip_rcv()
- netfilter hook NF_IP_PRE_ROUTING is called
- net/ipv4/netfilter/ip_conntrack_core.c:ip_conntrack_in() is called
- net/ipv4/netfilter/ip_conntrack_core.c:ip_ct_gather_frags() is called
- net/ipv4/ip_input.c:ip_defrag() is called
Isn't the skb->dev member supposed to still point to the receiving
device?
> David S. Miller
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