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,URIBL_BLOCKED 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 1EE2DC4360F for ; Thu, 21 Mar 2019 16:57:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EDB6B21902 for ; Thu, 21 Mar 2019 16:57:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728404AbfCUQ5P (ORCPT ); Thu, 21 Mar 2019 12:57:15 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:50282 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727829AbfCUQ5P (ORCPT ); Thu, 21 Mar 2019 12:57:15 -0400 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::3d5]) (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 C586B133E9753; Thu, 21 Mar 2019 09:57:14 -0700 (PDT) Date: Thu, 21 Mar 2019 09:57:12 -0700 (PDT) Message-Id: <20190321.095712.792633629065636362.davem@davemloft.net> To: hoang.h.le@dektech.com.au Cc: jon.maloy@ericsson.com, maloy@donjonn.com, ying.xue@windriver.com, tipc-discussion@lists.sourceforge.net, netdev@vger.kernel.org Subject: Re: [net-next v1 1/2] tipc: fix use-after-free in tipc_sk_filter_rcv From: David Miller In-Reply-To: <20190321102518.5048-1-hoang.h.le@dektech.com.au> References: <20190321102518.5048-1-hoang.h.le@dektech.com.au> 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]); Thu, 21 Mar 2019 09:57:15 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Hoang Le Date: Thu, 21 Mar 2019 17:25:17 +0700 > skb free-ed in: > 1/ condition 1: tipc_sk_filter_rcv -> tipc_sk_proto_rcv > 2/ condition 2: tipc_sk_filter_rcv -> tipc_group_filter_msg > This leads to a "use-after-free" access in the next condition. > > We fix this by intializing the variable at declaration, then it is safe > to check this variable to continue processing if condition matches. > > syzbot report: ... > Reported-by: syzbot+e863893591cc7a622e40@syzkaller.appspotmail.com > Fixes: c55c8eda ("tipc: smooth change between replicast and broadcast") > Acked-by: Jon Maloy > Signed-off-by: Hoang Le Applied.