From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mail.netfilter.org (mail.netfilter.org [217.70.188.207])
	by smtp.subspace.kernel.org (Postfix) with ESMTP id 874BB1F176
	for <netfilter-devel@vger.kernel.org>; Mon, 20 May 2024 18:33:41 +0000 (UTC)
Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.188.207
ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116;
	t=1716230025; cv=none; b=bfPynt79QGhIwbXhZsPEHx87uKpZuI517RETB1TTV0O7xfVebVdeS8VGYDHUtsDHfa8JWynVIijXmPT2stSG5XM/8VAJbeWeedPgR1IMoJSYngzNwlfJhKYjhDKCG8snB/zZLJIG1VKv68iobVWChSGnd8Klws4iN497uOX2JEw=
ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org;
	s=arc-20240116; t=1716230025; c=relaxed/simple;
	bh=M9eMhCQAu9PvKdnE+gSIcaTXV7aVHyGDac8aard5ZVI=;
	h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version:
	 Content-Type:Content-Disposition:In-Reply-To; b=h9V8/OWnkNOO9m/yzcX+dZ24+tDOJHPpqxkeYTJcjVEXgxmnl345SsnhNVIR6fvk0OxjhHGkKGB1sVHXBG7H+4aNGs0ps742T/mNf8xFQFkgBlsfXIrEE1E7FpBKTvStwmxEiDfaqyuvhreqlm/0dFVum+z6hOgVNj131VQKXBI=
ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org; spf=pass smtp.mailfrom=netfilter.org; arc=none smtp.client-ip=217.70.188.207
Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org
Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=netfilter.org
Date: Mon, 20 May 2024 20:33:36 +0200
From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Antonio Ojea <aojea@google.com>
Cc: netfilter-devel@vger.kernel.org, fw@strlen.de
Subject: Re: [PATCH v3 0/2] netfilter: nfqueue: incorrect sctp checksum
Message-ID: <ZkuXgB_Qo5336q4-@calendula>
References: <20240513220033.2874981-1-aojea@google.com>
 <Zkszmr7lNVte6iNu@calendula>
 <Zktv4TN-DPvCLCXZ@calendula>
Precedence: bulk
X-Mailing-List: netfilter-devel@vger.kernel.org
List-Id: <netfilter-devel.vger.kernel.org>
List-Subscribe: <mailto:netfilter-devel+subscribe@vger.kernel.org>
List-Unsubscribe: <mailto:netfilter-devel+unsubscribe@vger.kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <Zktv4TN-DPvCLCXZ@calendula>

On Mon, May 20, 2024 at 05:44:35PM +0200, Pablo Neira Ayuso wrote:
> On Mon, May 20, 2024 at 01:27:22PM +0200, Pablo Neira Ayuso wrote:
> > On Mon, May 13, 2024 at 10:00:31PM +0000, Antonio Ojea wrote:
> > > Fixes the bug described in
> > > https://bugzilla.netfilter.org/show_bug.cgi?id=1742
> > > causing netfilter to drop SCTP packets when using
> > > nfqueue and GSO due to incorrect checksum.
> > > 
> > > Patch 1 adds a new helper to process the sctp checksum
> > > correctly.
> > > 
> > > Patch 2 adds a selftest regression test.
> > 
> > I am inclined to integrated this into nf.git, I will pick a Fixes: tag
> > sufficiently old so -stable picks up.
> 
> I have to collapse this chunk, otherwise I hit one issue with missing
> exported symbol. No need to resend, I will amend here. Just for the
> record.

Hm. SCTP GSO support is different too, because it keeps a list of segments.

static int
nfqnl_enqueue_packet(struct nf_queue_entry *entry, unsigned int queuenum)
{
[...]
        if ((queue->flags & NFQA_CFG_F_GSO) || !skb_is_gso(skb))
                return __nfqnl_enqueue_packet(net, queue, entry);

I think this needs to be:

        if ((queue->flags & NFQA_CFG_F_GSO) || !skb_is_gso(skb) || !skb_is_gso_sctp(skb))
                return __nfqnl_enqueue_packet(net, queue, entry);

so SCTP GSO packets enters this path below:

        nf_bridge_adjust_skb_data(skb);
        segs = skb_gso_segment(skb, 0);

to deliver separated segments to userspace.

Otherwise, I don't see yet how userspace can deal with several SCTP
segments, from nf_reinject() there is a list of segments no more.