Re: [PATCH net] netfilter: nf_reject: don't leak dst refcount for loopback packets

[Florian Westphal <fw@strlen.de>]

Pablo Neira Ayuso <pablo@netfilter.org> wrote:
> > > Instead of checking hook just check if the skb already has a route
> > > attached to it.
> > 
> > Quick question: does inconditional route lookup work for br_netfilter?
> 
> Never mind, it should be fine, the fake dst get attached to the skb.

Good point, this changes behaviour for br_netfilter case, we no
longer call nf_reject_fill_skb_dst() then due to the fake dst.

I don't think br_netfilter is supposed to do anything (iptables
-j REJECT doesn't work in PRE_ROUTING), and we should not encourage
use of br_netfilter with nftables.

What about adding a followup patch, targetting nf, that adds:

if (hook == NF_INET_PRE_ROUTING && nf_bridge_info_exists(oldskb))
	return;

?

After all, there is no guarantee that we have the needed routing
info on a bridge in the first place.