From: Neil Horman <nhorman@tuxdriver.com>
To: Florian Westphal <fw@strlen.de>
Cc: Xin Long <lucien.xin@gmail.com>,
Pablo Neira Ayuso <pablo@netfilter.org>,
network dev <netdev@vger.kernel.org>,
netfilter-devel@vger.kernel.org,
Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Subject: Re: [PATCH net] netfilter: set skb transport_header before calling sctp_compute_cksum
Date: Mon, 11 Mar 2019 07:07:52 -0400 [thread overview]
Message-ID: <20190311110752.GA30241@hmswarspite.think-freely.org> (raw)
In-Reply-To: <20190309092434.oflik6j57yrhpkh5@breakpoint.cc>
On Sat, Mar 09, 2019 at 10:24:34AM +0100, Florian Westphal wrote:
> Xin Long <lucien.xin@gmail.com> wrote:
> > https://marc.info/?l=linux-netdev&m=155109395226858&w=2
> > But from sctp side, Neil preferred sctp_hdr().
> >
> > We need to either add skb_set_transport_header() in sctp_s/dnat_handler()
> > and sctp_manip_pkt(), or bring that patch back?
> >
> > Now it seems not good to set skb->transport_header in netfilter code.
>
> I think its fine, but I wonder why we need to do it.
>
> Since 21d1196a35f5686c4323e42a62fdb4b23b0ab4a3 ipv4 input path sets
> transport header before netfilter. The only problem is that linear
> access is illegal without may_pull checks, but in this case the
> make_writable call takes care of this already.
>
Yes, this. It seems to me we should be setting the transport header prior to
ever getting into the netfilter code, which does imply that we need the may_pull
check to linearize enough of the packet to do so, just like tcp and udp do.
> So, why was this patch needed?
> If we need it, do we also need to add it in other locations that
> deal with sctp csum (e.g. in ipvs?).
>
This is a fair question, and I'm not yet sure of the answer.
> Thanks,
> Florian
>
next prev parent reply other threads:[~2019-03-11 11:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-03 8:17 [PATCH net] netfilter: set skb transport_header before calling sctp_compute_cksum Xin Long
2019-03-08 15:50 ` Pablo Neira Ayuso
2019-03-09 9:07 ` Xin Long
2019-03-09 9:24 ` Florian Westphal
2019-03-11 11:07 ` Neil Horman [this message]
2019-03-12 8:39 ` Xin Long
2019-03-12 9:48 ` Pablo Neira Ayuso
2019-03-12 11:01 ` Xin Long
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