From: Florian Westphal <fw@strlen.de>
To: Jakub Kicinski <kuba@kernel.org>
Cc: Florian Westphal <fw@strlen.de>,
netdev@vger.kernel.org, davem@davemloft.net,
netfilter-devel@vger.kernel.org, pabeni@redhat.com,
edumazet@google.com, Pablo Neira Ayuso <pablo@netfilter.org>,
Aaron Conole <aconole@redhat.com>
Subject: Re: [PATCH net 1/4] netfilter: remove nf_conntrack_helper sysctl and modparam toggles
Date: Fri, 2 Sep 2022 07:39:28 +0200 [thread overview]
Message-ID: <20220902053928.GA5881@breakpoint.cc> (raw)
In-Reply-To: <20220901210715.00c7b4e1@kernel.org>
Jakub Kicinski <kuba@kernel.org> wrote:
> On Thu, 1 Sep 2022 09:12:35 +0200 Florian Westphal wrote:
> > From: Pablo Neira Ayuso <pablo@netfilter.org>
> >
> > __nf_ct_try_assign_helper() remains in place but it now requires a
> > template to configure the helper.
> >
> > A toggle to disable automatic helper assignment was added by:
> >
> > a9006892643a ("netfilter: nf_ct_helper: allow to disable automatic helper assignment")
> >
> > in 2012 to address the issues described in "Secure use of iptables and
> > connection tracking helpers". Automatic conntrack helper assignment was
> > disabled by:
> >
> > 3bb398d925ec ("netfilter: nf_ct_helper: disable automatic helper assignment")
> >
> > back in 2016.
> >
> > This patch removes the sysctl and modparam toggles, users now have to
> > rely on explicit conntrack helper configuration via ruleset.
> >
> > Update tools/testing/selftests/netfilter/nft_conntrack_helper.sh to
> > check that auto-assignment does not happen anymore.
>
> From the description itself it's unclear why this is a part of a net PR.
> Could you elucidate?
Yes, there is improper checking in the irc dcc helper, its possible to
trigger the 'please do dynamic port forward' from outside by embedding
a 'DCC' in a PING request; if the client echos that back a expectation/
port forward gets added.
A fix for this will come in the next net PR, however, one part of the
issue is that point-blank-autassign is problematic and that helpers
should only be enabled for addresses that need it.
If you like I can resend the PR with an updated cover letter, or resend
with the dcc helper fix included as well.
next prev parent reply other threads:[~2022-09-02 5:39 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-01 7:12 [PATCH net 0/4] netfilter: bug fixes for net Florian Westphal
2022-09-01 7:12 ` [PATCH net 1/4] netfilter: remove nf_conntrack_helper sysctl and modparam toggles Florian Westphal
2022-09-02 4:07 ` Jakub Kicinski
2022-09-02 5:39 ` Florian Westphal [this message]
2022-09-03 2:43 ` Jakub Kicinski
2022-09-03 4:20 ` patchwork-bot+netdevbpf
2022-09-01 7:12 ` [PATCH net 2/4] netfilter: br_netfilter: Drop dst references before setting Florian Westphal
2022-09-01 7:12 ` [PATCH net 3/4] netfilter: nf_tables: clean up hook list when offload flags check fails Florian Westphal
2022-09-01 7:12 ` [PATCH net 4/4] netfilter: nf_conntrack_irc: Fix forged IP logic Florian Westphal
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