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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 6FDB1C433ED for ; Mon, 12 Apr 2021 08:46:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4BE3E61278 for ; Mon, 12 Apr 2021 08:46:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237990AbhDLIrD (ORCPT ); Mon, 12 Apr 2021 04:47:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:38088 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237793AbhDLIpf (ORCPT ); Mon, 12 Apr 2021 04:45:35 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1908E6124C; Mon, 12 Apr 2021 08:45:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1618217117; bh=AdoQ38MBmprPvGcxgKXcjYRjkvnJr3ncsTjgYD25fAc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nr5mxy+cR1QpjEEcu0+wKuP6fiZsScqnP8iBYbawnxzSpKLnkY5oMQpo69GTUD2ch zK+sqVIp75+jYJasPv5qPteC9KA/Pt5TmHAaifeExTB8xht5wDzfjFwfgyrNI4gv7e Mjf4LfCd8TrQhti2uUIfQ1giqkbP98B3QkC5nm84= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Muhammad Usama Anjum , "David S. Miller" Subject: [PATCH 5.4 010/111] net: ipv6: check for validity before dereferencing cfg->fc_nlinfo.nlh Date: Mon, 12 Apr 2021 10:39:48 +0200 Message-Id: <20210412084004.561631412@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210412084004.200986670@linuxfoundation.org> References: <20210412084004.200986670@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Muhammad Usama Anjum commit 864db232dc7036aa2de19749c3d5be0143b24f8f upstream. nlh is being checked for validtity two times when it is dereferenced in this function. Check for validity again when updating the flags through nlh pointer to make the dereferencing safe. CC: Addresses-Coverity: ("NULL pointer dereference") Signed-off-by: Muhammad Usama Anjum Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv6/route.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -5183,9 +5183,11 @@ static int ip6_route_multipath_add(struc * nexthops have been replaced by first new, the rest should * be added to it. */ - cfg->fc_nlinfo.nlh->nlmsg_flags &= ~(NLM_F_EXCL | - NLM_F_REPLACE); - cfg->fc_nlinfo.nlh->nlmsg_flags |= NLM_F_CREATE; + if (cfg->fc_nlinfo.nlh) { + cfg->fc_nlinfo.nlh->nlmsg_flags &= ~(NLM_F_EXCL | + NLM_F_REPLACE); + cfg->fc_nlinfo.nlh->nlmsg_flags |= NLM_F_CREATE; + } nhn++; }