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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 0B160C432C1 for ; Tue, 24 Sep 2019 09:34:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D79242146E for ; Tue, 24 Sep 2019 09:34:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2504269AbfIXJeN (ORCPT ); Tue, 24 Sep 2019 05:34:13 -0400 Received: from szxga05-in.huawei.com ([45.249.212.191]:2773 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2504239AbfIXJeM (ORCPT ); Tue, 24 Sep 2019 05:34:12 -0400 Received: from DGGEMS408-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id D9E1F99325EA1F14D8C6; Tue, 24 Sep 2019 17:34:10 +0800 (CST) Received: from [127.0.0.1] (10.177.96.96) by DGGEMS408-HUB.china.huawei.com (10.3.19.208) with Microsoft SMTP Server id 14.3.439.0; Tue, 24 Sep 2019 17:34:05 +0800 Subject: Re: [PATCH stable 4.4 net] net: rds: Fix NULL ptr use in rds_tcp_kill_sock From: maowenan To: Greg KH CC: , , , , , , References: <20190918083733.50266-1-maowenan@huawei.com> <20190918083253.GA1862222@kroah.com> Message-ID: <8b5b7fd5-dd53-4a73-371d-c997b1b3ce78@huawei.com> Date: Tue, 24 Sep 2019 17:33:56 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.96.96] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Kindly ping... On 2019/9/18 17:02, maowenan wrote: > > > On 2019/9/18 16:32, Greg KH wrote: >> On Wed, Sep 18, 2019 at 04:37:33PM +0800, Mao Wenan wrote: >>> After the commit c4e97b06cfdc ("net: rds: force to destroy >>> connection if t_sock is NULL in rds_tcp_kill_sock()."), >>> it introduced null-ptr-deref in rds_tcp_kill_sock as below: >>> >>> BUG: KASAN: null-ptr-deref on address 0000000000000020 >>> Read of size 8 by task kworker/u16:10/910 >>> CPU: 3 PID: 910 Comm: kworker/u16:10 Not tainted 4.4.178+ #3 >>> Hardware name: linux,dummy-virt (DT) >>> Workqueue: netns cleanup_net >>> Call trace: >>> [] dump_backtrace+0x0/0x618 >>> [] show_stack+0x38/0x60 >>> [] dump_stack+0x1a8/0x230 >>> [] kasan_report_error+0xc8c/0xfc0 >>> [] kasan_report+0x94/0xd8 >>> [] __asan_load8+0x88/0x150 >>> [] rds_tcp_dev_event+0x734/0xb48 >>> [] raw_notifier_call_chain+0x150/0x1e8 >>> [] call_netdevice_notifiers_info+0x90/0x110 >>> [] netdev_run_todo+0x2f4/0xb08 >>> [] rtnl_unlock+0x2c/0x48 >>> [] default_device_exit_batch+0x444/0x528 >>> [] ops_exit_list+0x1c0/0x240 >>> [] cleanup_net+0x738/0xbf8 >>> [] process_one_work+0x96c/0x13e0 >>> [] worker_thread+0x7e0/0x1910 >>> [] kthread+0x304/0x390 >>> [] ret_from_fork+0x10/0x50 >>> >>> If the first loop add the tc->t_sock = NULL to the tmp_list, >>> 1). list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) >>> >>> then the second loop is to find connections to destroy, tc->t_sock >>> might equal NULL, and tc->t_sock->sk happens null-ptr-deref. >>> 2). list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node) >>> >>> Fixes: c4e97b06cfdc ("net: rds: force to destroy connection if t_sock is NULL in rds_tcp_kill_sock().") >>> Signed-off-by: Mao Wenan >>> --- >>> net/rds/tcp.c | 8 +++++--- >>> 1 file changed, 5 insertions(+), 3 deletions(-) >> >> Why is this not needed upstream as well? > Upstream does not use tc->t_sock in the second loop after below two patches. > afb4164d91c7 ("RDS: TCP: Refactor connection destruction to handle multiple paths") and > 2d746c93b6e5 ("rds: tcp: remove redundant function rds_tcp_conn_paths_destroy()") > >> >> 4.9.y? 4.14.y? anything else? > 4.19.y and 4.14.y exist rds_tcp_conn_paths_destroy() > to guarantee that. > +static void rds_tcp_conn_paths_destroy(struct rds_connection *conn) > +{ > + struct rds_conn_path *cp; > + struct rds_tcp_connection *tc; > + int i; > + struct sock *sk; > + > + for (i = 0; i < RDS_MPATH_WORKERS; i++) { > + cp = &conn->c_path[i]; > + tc = cp->cp_transport_data; > + if (!tc->t_sock) > + continue; > + sk = tc->t_sock->sk; > + sk->sk_prot->disconnect(sk, 0); > + tcp_done(sk); > + } > +} > + > >> >> thanks, >> >> greg k-h >> >> . >> > > > . >