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=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 08C0CC3A5A8 for ; Tue, 3 Sep 2019 19:32:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DCE3D2168B for ; Tue, 3 Sep 2019 19:32:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726635AbfICTcB (ORCPT ); Tue, 3 Sep 2019 15:32:01 -0400 Received: from correo.us.es ([193.147.175.20]:47896 "EHLO mail.us.es" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726005AbfICTcB (ORCPT ); Tue, 3 Sep 2019 15:32:01 -0400 Received: from antivirus1-rhel7.int (unknown [192.168.2.11]) by mail.us.es (Postfix) with ESMTP id 809C4E2C50 for ; Tue, 3 Sep 2019 21:31:57 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id 729EAFB362 for ; Tue, 3 Sep 2019 21:31:57 +0200 (CEST) Received: by antivirus1-rhel7.int (Postfix, from userid 99) id 67D0EDA8E8; Tue, 3 Sep 2019 21:31:57 +0200 (CEST) Received: from antivirus1-rhel7.int (localhost [127.0.0.1]) by antivirus1-rhel7.int (Postfix) with ESMTP id A3DF4B7FF2; Tue, 3 Sep 2019 21:31:54 +0200 (CEST) Received: from 192.168.1.97 (192.168.1.97) by antivirus1-rhel7.int (F-Secure/fsigk_smtp/550/antivirus1-rhel7.int); Tue, 03 Sep 2019 21:31:54 +0200 (CEST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/antivirus1-rhel7.int) Received: from us.es (sys.soleta.eu [212.170.55.40]) (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 724554251480; Tue, 3 Sep 2019 21:31:54 +0200 (CEST) Date: Tue, 3 Sep 2019 21:31:55 +0200 X-SMTPAUTHUS: auth mail.us.es From: Pablo Neira Ayuso To: Florian Westphal Cc: Leonardo Bras , netfilter-devel@vger.kernel.org, coreteam@netfilter.org, bridge@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Jozsef Kadlecsik , Roopa Prabhu , Nikolay Aleksandrov , "David S. Miller" Subject: Re: [PATCH v4 1/2] netfilter: Terminate rule eval if protocol=IPv6 and ipv6 module is disabled Message-ID: <20190903193155.v74ws47zcn6zrwpr@salvia> References: <20190830181354.26279-1-leonardo@linux.ibm.com> <20190830181354.26279-2-leonardo@linux.ibm.com> <20190830205802.GS20113@breakpoint.cc> <99e3ef9c5ead1c95df697d49ab9cc83a95b0ac7c.camel@linux.ibm.com> <20190903164948.kuvtpy7viqhcmp77@salvia> <20190903170550.GA13660@breakpoint.cc> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190903170550.GA13660@breakpoint.cc> User-Agent: NeoMutt/20170113 (1.7.2) X-Virus-Scanned: ClamAV using ClamSMTP Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org On Tue, Sep 03, 2019 at 07:05:50PM +0200, Florian Westphal wrote: > Pablo Neira Ayuso wrote: > > On Tue, Sep 03, 2019 at 01:46:50PM -0300, Leonardo Bras wrote: > > > On Fri, 2019-08-30 at 22:58 +0200, Florian Westphal wrote: > > > > Leonardo Bras wrote: > > > > > If IPv6 is disabled on boot (ipv6.disable=1), but nft_fib_inet ends up > > > > > dealing with a IPv6 packet, it causes a kernel panic in > > > > > fib6_node_lookup_1(), crashing in bad_page_fault. > > > > > > > > > > The panic is caused by trying to deference a very low address (0x38 > > > > > in ppc64le), due to ipv6.fib6_main_tbl = NULL. > > > > > BUG: Kernel NULL pointer dereference at 0x00000038 > > > > > > > > > > The kernel panic was reproduced in a host that disabled IPv6 on boot and > > > > > have to process guest packets (coming from a bridge) using it's ip6tables. > > > > > > > > > > Terminate rule evaluation when packet protocol is IPv6 but the ipv6 module > > > > > is not loaded. > > > > > > > > > > Signed-off-by: Leonardo Bras > > > > > > > > Acked-by: Florian Westphal > > > > > > > > > > Hello Pablo, > > > > > > Any trouble with this patch? > > > I could see the other* one got applied, but not this one. > > > *(The other did not get acked, so i released it alone as v5) > > > > > > Is there any fix I need to do in this one? > > > > Hm, I see, so this one: > > > > https://patchwork.ozlabs.org/patch/1156100/ > > > > is not enough? > > No, its not. > > > I was expecting we could find a way to handle this from br_netfilter > > alone itself. > > We can't because we support ipv6 fib lookups from the netdev family > as well. > > Alternative is to auto-accept ipv6 packets from the nf_tables eval loop, > but I think its worse. Could we add a restriction for nf_tables + br_netfilter + !ipv6. I mean, if this is an IPv6 packet, nf_tables is on and IPv6 module if off, then drop this packet? By dropping packet, the user could diagnose that its setup is incomplete. I mean, if nf_tables fib ipv6 is used, then this setup is really wrong and the user forgots to load the ipv6 module.