From: Jakub Kicinski <kuba@kernel.org>
To: Samuel Moelius <sam.moelius@trailofbits.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>,
Jiri Pirko <jiri@resnulli.us>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>, Simon Horman <horms@kernel.org>,
netdev@vger.kernel.org (open list:TC subsystem),
linux-kernel@vger.kernel.org (open list)
Subject: Re: [PATCH] net/sched: act_csum: skip malformed IPv4 headers
Date: Wed, 10 Jun 2026 08:09:17 -0700 [thread overview]
Message-ID: <20260610080917.52135297@kernel.org> (raw)
In-Reply-To: <20260605152916.2125473-1-sam.moelius@trailofbits.com>
On Fri, 5 Jun 2026 15:29:15 +0000 Samuel Moelius wrote:
> act_csum trusts the IPv4 IHL field before using it to locate transport
> header fields. Packets with an invalid short IHL can make the action
> write checksum data into the IPv4 header instead of the intended L4
> header.
>
> The action should not repair or modify packets whose IPv4 header length
> is invalid. Treat those packets as not eligible for checksum repair and
> leave the configured action result unchanged.
I could be wrong but I think we were trying to prevent such packets
from getting in rather than fix all the places that call ip_hdr()?
Someone please correct me if I'm wrong, or ack this, otherwise I'll
toss this patch..
--
pw-bot: reject
prev parent reply other threads:[~2026-06-10 15:09 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-05 15:29 [PATCH] net/sched: act_csum: skip malformed IPv4 headers Samuel Moelius
2026-06-10 15:09 ` Jakub Kicinski [this message]
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