Re: [PATCH] net: fix duplicate logs of iptables TRACE target

Florian Westphal
2022-01-24T07:21:36Z

kai zhang <zhangkaiheb@126.com> wrote:
> Below configuration, mangle,filter and security tables have no rule:
>
> There are 5 logs for incoming ssh packet:
>
> kernel: [ 7018.727278] TRACE: raw:PREROUTING:policy:2 IN=enp9s0 ...
> kernel: [ 7018.727304] TRACE: mangle:PREROUTING:policy:1 IN=enp9s0 ...
> kernel: [ 7018.727327] TRACE: mangle:INPUT:policy:1 IN=enp9s0 ...
> kernel: [ 7018.727343] TRACE: filter:INPUT:policy:1 IN=enp9s0 ...
> kernel: [ 7018.727359] TRACE: security:INPUT:policy:1 IN=enp9s0 ...

Thats correct and exactly whats supposed to happen.

> #if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE)
> /* The packet is traced: log it */
> - if (unlikely(skb->nf_trace))
> + if (unlikely(skb->nf_trace)) {
> trace_packet(state->net, skb, hook, state->in,
> state->out, table->name, private, e);
> + nf_reset_trace(skb);
> + }

This breaks the long established behavior of TRACE,
we don't want users to have to TRACE tables individually which may also
be hard when nat is involved.