From patchwork Thu Apr 15 14:46:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 423344 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=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 00F64C433ED for ; Thu, 15 Apr 2021 14:57:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DB233613C3 for ; Thu, 15 Apr 2021 14:57:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233758AbhDOO5g (ORCPT ); Thu, 15 Apr 2021 10:57:36 -0400 Received: from mail.kernel.org ([198.145.29.99]:40268 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234321AbhDOOzf (ORCPT ); Thu, 15 Apr 2021 10:55:35 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 645A8613A9; Thu, 15 Apr 2021 14:53:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1618498422; bh=hjnrXiOy1eh8Nvt+i7eLpbDfpBf5i3P8ESgLZO6JydI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zrXaKYf0W/ZqEjYh5sOZHqasFKlI3Letb7pDdYbK11C9xVS4ONhlWqPsr0sIGCdP2 LuF1pCIGyMKeX5t+alcYDKtspVj8tESI2Yo6fvvU8L5Weg/yvEHaQ8ygpiVYYqK6LB KcWkTVU75q2AWcUVE1dtFSIcbvcpgeGtUb9lLDxU= 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 4.14 08/68] net: ipv6: check for validity before dereferencing cfg->fc_nlinfo.nlh Date: Thu, 15 Apr 2021 16:46:49 +0200 Message-Id: <20210415144414.743874547@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210415144414.464797272@linuxfoundation.org> References: <20210415144414.464797272@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@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 @@ -3283,9 +3283,11 @@ 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++; }