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 96229C3A59B for ; Fri, 30 Aug 2019 20:58:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 75BBA23429 for ; Fri, 30 Aug 2019 20:58:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728237AbfH3U6K (ORCPT ); Fri, 30 Aug 2019 16:58:10 -0400 Received: from Chamillionaire.breakpoint.cc ([193.142.43.52]:58896 "EHLO Chamillionaire.breakpoint.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728067AbfH3U6K (ORCPT ); Fri, 30 Aug 2019 16:58:10 -0400 Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1i3ny6-0006SE-KB; Fri, 30 Aug 2019 22:58:02 +0200 Date: Fri, 30 Aug 2019 22:58:02 +0200 From: Florian Westphal To: Leonardo Bras Cc: netfilter-devel@vger.kernel.org, coreteam@netfilter.org, bridge@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Pablo Neira Ayuso , Jozsef Kadlecsik , Florian Westphal , 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: <20190830205802.GS20113@breakpoint.cc> References: <20190830181354.26279-1-leonardo@linux.ibm.com> <20190830181354.26279-2-leonardo@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190830181354.26279-2-leonardo@linux.ibm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: netfilter-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org 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