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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 84773C43381 for ; Wed, 6 Mar 2019 18:38:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5BA532133F for ; Wed, 6 Mar 2019 18:38:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727134AbfCFSh7 (ORCPT ); Wed, 6 Mar 2019 13:37:59 -0500 Received: from shards.monkeyblade.net ([23.128.96.9]:38956 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728171AbfCFSh7 (ORCPT ); Wed, 6 Mar 2019 13:37:59 -0500 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::d71]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 64B0C144FEB5F; Wed, 6 Mar 2019 10:37:58 -0800 (PST) Date: Wed, 06 Mar 2019 10:37:57 -0800 (PST) Message-Id: <20190306.103757.1493556167593143047.davem@davemloft.net> To: pabeni@redhat.com Cc: netdev@vger.kernel.org, dsa@cumulusnetworks.com Subject: Re: [PATCH net v2] ipv4/route: fail early when inet dev is missing From: David Miller In-Reply-To: References: X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Wed, 06 Mar 2019 10:37:58 -0800 (PST) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Paolo Abeni Date: Wed, 6 Mar 2019 10:42:53 +0100 > If a non local multicast packet reaches ip_route_input_rcu() while > the ingress device IPv4 private data (in_dev) is NULL, we end up > doing a NULL pointer dereference in IN_DEV_MFORWARD(). > > Since the later call to ip_route_input_mc() is going to fail if > !in_dev, we can fail early in such scenario and avoid the dangerous > code path. > > v1 -> v2: > - clarified the commit message, no code changes > > Reported-by: Tianhao Zhao > Fixes: e58e41596811 ("net: Enable support for VRF with ipv4 multicast") > Signed-off-by: Paolo Abeni > Reviewed-by: David Ahern Applied and queued up for -stable.