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, URIBL_BLOCKED,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 9465BC433B4 for ; Thu, 15 Apr 2021 14:50:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 78D0E613CB for ; Thu, 15 Apr 2021 14:50:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233524AbhDOOul (ORCPT ); Thu, 15 Apr 2021 10:50:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:37562 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233854AbhDOOuJ (ORCPT ); Thu, 15 Apr 2021 10:50:09 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 311B4613CC; Thu, 15 Apr 2021 14:49:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1618498186; bh=5B0FtqAekw/UCDUpLgN3upPE0PsH0a4hB3BtH20oZlk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DbBwtEUixUSy/FepPZg8q7cLAohmxxyfd+xiFcL5Rk2Hj4J41v5BH4BpBo8ms8jcF XfCGr/NGtrX2G2Xk94i1PA5nqpuqzsWoWKCMx7O7ACg7O3MkkNwEr0QzTkwucs3hTs NYNwdrsLa9qZnDUNmLXbNYQOpeium2oOsPsVHxhQ= 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 4.4 08/38] net: ipv6: check for validity before dereferencing cfg->fc_nlinfo.nlh Date: Thu, 15 Apr 2021 16:47:02 +0200 Message-Id: <20210415144413.619158550@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210415144413.352638802@linuxfoundation.org> References: <20210415144413.352638802@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 @@ -2980,9 +2980,11 @@ 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++; }