Netdev List
 help / color / mirror / Atom feed
From: Herbert Xu <herbert@gondor.apana.org.au>
To: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Michael Bommarito <michael.bommarito@gmail.com>,
	Steffen Klassert <steffen.klassert@secunet.com>,
	Eric Dumazet <edumazet@google.com>,
	netdev@vger.kernel.org, "David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Kuniyuki Iwashima <kuniyu@google.com>,
	Maciej Zenczykowski <maze@google.com>,
	Kees Cook <kees@kernel.org>, Jeff Layton <jlayton@kernel.org>,
	"Gustavo A . R . Silva" <gustavoars@kernel.org>,
	Florian Westphal <fw@strlen.de>,
	netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH net 0/2] ipv4: harden against ihl < 5 IP_HDRINCL packets
Date: Fri, 15 May 2026 12:22:40 +0800	[thread overview]
Message-ID: <agafkH9xcE9m7P6Q@gondor.apana.org.au> (raw)
In-Reply-To: <agOrCj3YoMAxsxYf@chamomile>

On Wed, May 13, 2026 at 12:34:50AM +0200, Pablo Neira Ayuso wrote:
> 
> There are possibly more ways to mangle ihl in the kernel in 2026, not
> only NFQUEUE and nft_payload.

If a packet will be processed further by our stack, we should not
allow it to be modified in such a way that it becomes a threat
to our network stack's consistency.

This is especially the case in containers where unprivileged users
may be able to create these mangling rules.

So any time after a packet has been mangled by nftables where it
may result in a bogus packet, it needs to be checked for consistency
before it is reinjected into our IP stack.

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

      parent reply	other threads:[~2026-05-15  4:22 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-12 20:51 [PATCH net 0/2] ipv4: harden against ihl < 5 IP_HDRINCL packets Michael Bommarito
2026-05-12 20:51 ` [PATCH net 1/2] ipv4: raw: reject IP_HDRINCL packets with ihl < 5 Michael Bommarito
2026-05-12 20:51 ` [PATCH net 2/2] ipv4: ah: harden ah_output options-copy guard against " Michael Bommarito
2026-05-15  4:20   ` Herbert Xu
2026-05-12 22:34 ` [PATCH net 0/2] ipv4: harden against ihl < 5 IP_HDRINCL packets Pablo Neira Ayuso
2026-05-12 23:05   ` Michael Bommarito
2026-05-15  4:22   ` Herbert Xu [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=agafkH9xcE9m7P6Q@gondor.apana.org.au \
    --to=herbert@gondor.apana.org.au \
    --cc=coreteam@netfilter.org \
    --cc=davem@davemloft.net \
    --cc=edumazet@google.com \
    --cc=fw@strlen.de \
    --cc=gustavoars@kernel.org \
    --cc=jlayton@kernel.org \
    --cc=kees@kernel.org \
    --cc=kuba@kernel.org \
    --cc=kuniyu@google.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=maze@google.com \
    --cc=michael.bommarito@gmail.com \
    --cc=netdev@vger.kernel.org \
    --cc=netfilter-devel@vger.kernel.org \
    --cc=pabeni@redhat.com \
    --cc=pablo@netfilter.org \
    --cc=steffen.klassert@secunet.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox