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=ham 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 38CF3C3A5A2 for ; Tue, 3 Sep 2019 17:06:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0A89220870 for ; Tue, 3 Sep 2019 17:05:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730126AbfICRF7 (ORCPT ); Tue, 3 Sep 2019 13:05:59 -0400 Received: from Chamillionaire.breakpoint.cc ([193.142.43.52]:42914 "EHLO Chamillionaire.breakpoint.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727107AbfICRF6 (ORCPT ); Tue, 3 Sep 2019 13:05:58 -0400 Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1i5CFa-0003c1-IC; Tue, 03 Sep 2019 19:05:50 +0200 Date: Tue, 3 Sep 2019 19:05:50 +0200 From: Florian Westphal To: Pablo Neira Ayuso 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, FlorianWestphal , 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: <20190903170550.GA13660@breakpoint.cc> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190903164948.kuvtpy7viqhcmp77@salvia> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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.