From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phil Sutter Subject: Re: [iptables PATCH] extensions: libxt_conntrack: Fix 'state' translation to nft Date: Wed, 8 Mar 2017 13:31:51 +0100 Message-ID: <20170308123151.GA6028@orbyte.nwl.cc> References: <20170307153507.14640-1-phil@nwl.cc> <20170307161729.GA2233@salvia> <20170307162055.GA4753@salvia> <20170307165409.GB19869@orbyte.nwl.cc> <20170307193158.GA19663@salvia> <20170307200745.GC19869@orbyte.nwl.cc> <20170308103652.GA3800@salvia> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netfilter-devel@vger.kernel.org To: Pablo Neira Ayuso Return-path: Received: from orbyte.nwl.cc ([151.80.46.58]:36447 "EHLO mail.nwl.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752990AbdCHMbx (ORCPT ); Wed, 8 Mar 2017 07:31:53 -0500 Content-Disposition: inline In-Reply-To: <20170308103652.GA3800@salvia> Sender: netfilter-devel-owner@vger.kernel.org List-ID: On Wed, Mar 08, 2017 at 11:36:52AM +0100, Pablo Neira Ayuso wrote: > On Tue, Mar 07, 2017 at 09:07:45PM +0100, Phil Sutter wrote: > > On Tue, Mar 07, 2017 at 08:31:58PM +0100, Pablo Neira Ayuso wrote: > > > On Tue, Mar 07, 2017 at 05:54:09PM +0100, Phil Sutter wrote: > > > > On Tue, Mar 07, 2017 at 05:20:55PM +0100, Pablo Neira Ayuso wrote: > > > > > On Tue, Mar 07, 2017 at 05:17:29PM +0100, Pablo Neira Ayuso wrote: > > > > > > On Tue, Mar 07, 2017 at 04:35:07PM +0100, Phil Sutter wrote: > > > > > > > While translating a conntrack state match in old syntax, matches are > > > > > > > looked up by name, only. This returned the revision 0 entry since > > > > > > > matches are registered in reverse order of appearance in the array > > > > > > > passed to xtables_register_matches(). The problem is that revision 0 > > > > > > > doesn't define an xlate callback. > > > > > > > > > > > > > > Fix this by reordering the matches in conntrack_mt_reg so that the > > > > > > > highest revision one is found first. > > > > > > > > > > > > Applied, thanks Phil. > > > > > > > > > > Wait. > > > > > > > > > > Do you mean this case? > > > > > > > > > > # iptables-translate -I INPUT -m state --state NEW > > > > > nft insert rule ip filter INPUT ct state new counter > > > > > > > > > > Hm, this works here. > > > > > > > > Yes, that's it. And it working for you just emphasizes something's fishy > > > > here. I just reverted my patch, then it's like this: > > > > > > > > | $ ./configure --prefix=$PWD/install && make && make install > > > > | [...] > > > > | $ ./install/sbin/iptables-translate -I INPUT -m state --state NEW > > > > | nft # -I INPUT -m state --state NEW > > > > > > > > Using 'strace -eopen' I see that libxt_state.so from the install > > > > destination is used, not the system one. > > > > > > > > Also, I did this change for debugging: > > > > > > > > | --- a/iptables/xtables-translate.c > > > > | +++ b/iptables/xtables-translate.c > > > > | @@ -100,6 +100,10 @@ int xlate_matches(const struct iptables_command_state *cs, struct xt_xlate *xl) > > > > | .escape_quotes = !cs->restore, > > > > | }; > > > > | > > > > | + printf("found match %s, rev %u, xlate is %p\n", > > > > | + matchp->match->name, > > > > | + matchp->match->revision, > > > > | + matchp->match->xlate); > > > > | if (!matchp->match->xlate) > > > > | return 0; > > > > > > > > The output is then: > > > > > > > > | $ ./install/sbin/iptables-translate -I INPUT -m state --state NEW > > > > | nft found match state, rev 0, xlate is (nil) > > > > | # -I INPUT -m state --state NEW > > > > > > > > Am I missing something?? > > > > > > Via nft_compatible_revision() I'm getting revision 3. Are you using > > > latest kernel from git? > > > > No, I'm running 4.9.10-gentoo here. But a quick test with nf-next kernel > > from Feb 23rd in a VM shows the same result. I have libnftnl-1.0.6 > > installed, is that relevant? > > I have a way to trigger this here, but not sure if that is the problem > there. If the kernel comes with no nft_compat support, then > nft_compatible_revision() fails, and > xtables_fully_register_pending_match() ends up selecting revision 0. > > In such case, I can reproduce your problem. > > # iptables-translate -A INPUT -m state --state NEW > nft # -A INPUT -m state --state NEW Ah! On my system, nft_compat is built as module and it didn't matter whether I have it loaded or not, nft_compatible_revision() would never succeed. Oh man, I just found the cause: I was running iptables-translate as unprivileged user. Calling it with sudo magically makes everything work. I'll have a look whether it's possible to communicate the received -EPERM back to the user. Cheers, Phil