From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 09E97C4363D for ; Fri, 2 Oct 2020 14:39:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C0256206B2 for ; Fri, 2 Oct 2020 14:39:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387807AbgJBOja (ORCPT ); Fri, 2 Oct 2020 10:39:30 -0400 Received: from correo.us.es ([193.147.175.20]:34220 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726017AbgJBOja (ORCPT ); Fri, 2 Oct 2020 10:39:30 -0400 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 1BE9A9ED51 for ; Fri, 2 Oct 2020 16:39:29 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 0D62CDA78A for ; Fri, 2 Oct 2020 16:39:29 +0200 (CEST) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id 02FACDA730; Fri, 2 Oct 2020 16:39:29 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id CBEF1DA789; Fri, 2 Oct 2020 16:39:26 +0200 (CEST) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Fri, 02 Oct 2020 16:39:26 +0200 (CEST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from us.es (unknown [90.77.255.23]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: 1984lsi) by entrada.int (Postfix) with ESMTPSA id AD0BE42EF9E2; Fri, 2 Oct 2020 16:39:26 +0200 (CEST) Date: Fri, 2 Oct 2020 16:39:26 +0200 X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: Phil Sutter , Arturo Borrero Gonzalez , netfilter-devel@vger.kernel.org Subject: Re: [iptables PATCH] iptables-nft: fix basechain policy configuration Message-ID: <20201002143926.GA1254@salvia> References: <160163907669.18523.7311010971070291883.stgit@endurance> <20201002120732.GB29050@orbyte.nwl.cc> <20201002121558.GA1367@salvia> <20201002122852.GC29050@orbyte.nwl.cc> <20201002124741.GA2232@salvia> <20201002133127.GD29050@orbyte.nwl.cc> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20201002133127.GD29050@orbyte.nwl.cc> User-Agent: Mutt/1.10.1 (2018-07-13) X-Virus-Scanned: ClamAV using ClamSMTP Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org On Fri, Oct 02, 2020 at 03:31:27PM +0200, Phil Sutter wrote: > On Fri, Oct 02, 2020 at 02:47:41PM +0200, Pablo Neira Ayuso wrote: > > On Fri, Oct 02, 2020 at 02:28:52PM +0200, Phil Sutter wrote: > > > On Fri, Oct 02, 2020 at 02:15:58PM +0200, Pablo Neira Ayuso wrote: > > > > On Fri, Oct 02, 2020 at 02:07:32PM +0200, Phil Sutter wrote: > > > > > Hi, > > > > > > > > > > On Fri, Oct 02, 2020 at 01:44:36PM +0200, Arturo Borrero Gonzalez wrote: > > > > > > Previous to this patch, the basechain policy could not be properly configured if it wasn't > > > > > > explictly set when loading the ruleset, leading to iptables-nft-restore (and ip6tables-nft-restore) > > > > > > trying to send an invalid ruleset to the kernel. > > > > > > > > > > I fear this is not sufficient: iptables-legacy-restore leaves the > > > > > previous chain policy in place if '-' is given in dump file. Please try > > > > > this snippet from a testcase I wrote: > > > > > > > > > > $XT_MULTI iptables -P FORWARD DROP > > > > > > > > > > diff -u -Z <($XT_MULTI iptables-save | grep '^:FORWARD') \ > > > > > <(echo ":FORWARD DROP [0:0]") > > > > > > > > > > $XT_MULTI iptables-restore -c <<< "$TEST_RULESET" > > > > > diff -u -Z <($XT_MULTI iptables-save | grep '^:FORWARD') \ > > > > > <(echo ":FORWARD DROP [0:0]") > > > > > > > > Hm, this is how it works in this patch right? > > > > > > > > I mean, if '-' is given, chain policy attribute in the netlink message > > > > is not set, and the kernel sets chain policy to > > > > NFT_CHAIN_POLICY_UNSET. > > > > > > > > Or am I missing anything? > > > > > > This is *flushing* iptables-restore. We're dropping the chain first and > > > then reinstall it. > > > > OK, so this fix only works with --noflush. > > > > If --noflush is not specified, then it should be possible to extend > > the cache to dump the chains, get the existing policy and use it. > > nft_cmd_chain_restore() already sets NFT_CL_CHAINS. > > > There is now a phase to evaluate the cache requirements, so you can > > fetch this. Then, from the netlink phase, look up for the existing > > policy in the cache and use it. > > After the cache is fetched, nft_table_flush() runs before > nft_chain_restore() does. > > > > Another quirk is that iptables-legacy-restore ignores the counters if > > > policy is '-' even if --counters flag was given. (: > > > > OK, so this needs two more fixed on top of this one. > > In Arturo's mail, he doesn't use --noflush. Not sure if this is just his > reproducer or if OpenStack doesn't use --noflush, either. If so, your > fix won't help with his problem. > > Arturo, does fixing --noflush suffice for your case? If so, we could > delay the "--flush" case "for later". ;) I would expect OpenStack uses --noflush. I'm not sure I can find a use-case for the "--flush" case with policy '-'. Let's wait for Arturo's feedback.