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 11269C43600 for ; Mon, 12 Apr 2021 09:29:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CB39560FD8 for ; Mon, 12 Apr 2021 09:29:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240952AbhDLJZD (ORCPT ); Mon, 12 Apr 2021 05:25:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:54822 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237550AbhDLJBl (ORCPT ); Mon, 12 Apr 2021 05:01:41 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 4779961382; Mon, 12 Apr 2021 09:00:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1618218022; bh=xP7z3D3xVMshlpGHETo/ZM6PXFeJURpMtgodQtBDOm4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yYhMREDz7QUDAunhzeYHMMSUyqOLKc+U2N+M2JJLDeCstdHQOhyJYKHV7wALF9tQZ ShcBRFDH9oq2hZAV8rsWb1t0Lq6f8mYtf3FtJSAq9kd2vpbRCklFpDzIWeJ9lz1zFf t7wTqGO4Z8bkxHQdJ3qrR+GrySQR5wHgi+dRyhlk= 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 5.11 015/210] net: ipv6: check for validity before dereferencing cfg->fc_nlinfo.nlh Date: Mon, 12 Apr 2021 10:38:40 +0200 Message-Id: <20210412084016.513159862@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210412084016.009884719@linuxfoundation.org> References: <20210412084016.009884719@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 @@ -5203,9 +5203,11 @@ 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++; }