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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 CA7A1C4CEC4 for ; Wed, 18 Sep 2019 08:20:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AB1D420640 for ; Wed, 18 Sep 2019 08:20:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730078AbfIRIUh (ORCPT ); Wed, 18 Sep 2019 04:20:37 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:39002 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726131AbfIRIUh (ORCPT ); Wed, 18 Sep 2019 04:20:37 -0400 Received: from DGGEMS404-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id B7BC91C5257CB8FD5C30; Wed, 18 Sep 2019 16:20:34 +0800 (CST) Received: from localhost.localdomain.localdomain (10.175.113.25) by DGGEMS404-HUB.china.huawei.com (10.3.19.204) with Microsoft SMTP Server id 14.3.439.0; Wed, 18 Sep 2019 16:20:27 +0800 From: Mao Wenan To: , , CC: , , , , Mao Wenan Subject: [PATCH stable 4.4 net] net: rds: Fix NULL ptr use in rds_tcp_kill_sock Date: Wed, 18 Sep 2019 16:37:33 +0800 Message-ID: <20190918083733.50266-1-maowenan@huawei.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.113.25] X-CFilter-Loop: Reflected Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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(-) diff --git a/net/rds/tcp.c b/net/rds/tcp.c index 554d4b461983..c10622a9321c 100644 --- a/net/rds/tcp.c +++ b/net/rds/tcp.c @@ -352,9 +352,11 @@ static void rds_tcp_kill_sock(struct net *net) } spin_unlock_irq(&rds_tcp_conn_lock); list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node) { - sk = tc->t_sock->sk; - sk->sk_prot->disconnect(sk, 0); - tcp_done(sk); + if (tc->t_sock) { + sk = tc->t_sock->sk; + sk->sk_prot->disconnect(sk, 0); + tcp_done(sk); + } if (tc->conn->c_passive) rds_conn_destroy(tc->conn->c_passive); rds_conn_destroy(tc->conn); -- 2.20.1