From: Pablo Neira Ayuso <pablo@netfilter.org>
To: zhangmh25@mails.tsinghua.edu.cn
Cc: netfilter-devel@vger.kernel.org, jianjun@tsinghua.edu.cn
Subject: Re: [PATCH nf-next v2] netfilter: nf_reject: validate TCP header length before sending resets
Date: Tue, 10 Nov 2026 02:07:03 +0100 [thread overview]
Message-ID: <avJuN1cClzssVmi0@chamomile> (raw)
In-Reply-To: <20261109164726.3868529-1-zhangmh25@mails.tsinghua.edu.cn>
On Tue, Nov 10, 2026 at 12:47:26AM +0800, zhangmh25@mails.tsinghua.edu.cn wrote:
> From: Minghao Zhang <zhangmh25@mails.tsinghua.edu.cn>
>
[...]
> With connection tracking enabled, segments with an inconsistent data
> offset are already flagged by tcp_error() in nf_conntrack_proto_tcp.c
> (th->doff*4 < sizeof(struct tcphdr) || tcplen < th->doff*4) on the
> paths where conntrack runs before the reject rule, so rulesets with
> an early "ct state invalid drop" rule never pass them to the reject
> target. The netdev and inet ingress reject paths run before conntrack
> and are not covered by that. The affected configurations are stateless
> rulesets, netdev-family reject rules, and rulesets whose reject rule
> is not preceded by an invalid-state drop.
I am not sure I want to duplicate all these checks that already exist
in nf_conntrack only for the stateless case.
prev parent reply other threads:[~2026-11-10 1:07 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-09 16:47 [PATCH nf-next v2] netfilter: nf_reject: validate TCP header length before sending resets zhangmh25
2026-11-10 1:07 ` Pablo Neira Ayuso [this message]
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