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, 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 5C0BDC43603 for ; Thu, 12 Dec 2019 21:36:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3446620663 for ; Thu, 12 Dec 2019 21:36:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731156AbfLLVgT (ORCPT ); Thu, 12 Dec 2019 16:36:19 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:65496 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1731134AbfLLVgS (ORCPT ); Thu, 12 Dec 2019 16:36:18 -0500 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id xBCLYJoM016330 for ; Thu, 12 Dec 2019 16:36:16 -0500 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0a-001b2d01.pphosted.com with ESMTP id 2wujxrq6ak-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 12 Dec 2019 16:36:16 -0500 Received: from localhost by e06smtp04.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 12 Dec 2019 21:36:12 -0000 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id xBCLaAgL45940772 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 12 Dec 2019 21:36:10 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B71594C044; Thu, 12 Dec 2019 21:36:10 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 7A5CE4C040; Thu, 12 Dec 2019 21:36:10 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 12 Dec 2019 21:36:10 +0000 (GMT) From: Karsten Graul To: davem@davemloft.net Cc: netdev@vger.kernel.org, linux-s390@vger.kernel.org, heiko.carstens@de.ibm.com, raspl@linux.ibm.com, ubraun@linux.ibm.com Subject: [PATCH net] net/smc: add fallback check to connect() Date: Thu, 12 Dec 2019 22:35:58 +0100 X-Mailer: git-send-email 2.17.1 X-TM-AS-GCONF: 00 x-cbid: 19121221-0016-0000-0000-000002D43F0F X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19121221-0017-0000-0000-000033366780 Message-Id: <20191212213558.10564-1-kgraul@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,18.0.572 definitions=2019-12-12_07:2019-12-12,2019-12-12 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 lowpriorityscore=0 malwarescore=0 mlxlogscore=999 impostorscore=0 priorityscore=1501 clxscore=1015 suspectscore=1 bulkscore=0 spamscore=0 adultscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-1912120165 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Ursula Braun FASTOPEN setsockopt() or sendmsg() may switch the SMC socket to fallback mode. Once fallback mode is active, the native TCP socket functions are called. Nevertheless there is a small race window, when FASTOPEN setsockopt/sendmsg runs in parallel to a connect(), and switch the socket into fallback mode before connect() takes the sock lock. Make sure the SMC-specific connect setup is omitted in this case. This way a syzbot-reported refcount problem is fixed, triggered by different threads running non-blocking connect() and FASTOPEN_KEY setsockopt. Reported-by: syzbot+96d3f9ff6a86d37e44c8@syzkaller.appspotmail.com Fixes: 6d6dd528d5af ("net/smc: fix refcount non-blocking connect() -part 2") Signed-off-by: Ursula Braun Signed-off-by: Karsten Graul --- net/smc/af_smc.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index b997072c72e5..cee5bf4a9bb9 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -857,6 +857,8 @@ static int smc_connect(struct socket *sock, struct sockaddr *addr, goto out; sock_hold(&smc->sk); /* sock put in passive closing */ + if (smc->use_fallback) + goto out; if (flags & O_NONBLOCK) { if (schedule_work(&smc->connect_work)) smc->connect_nonblock = 1; @@ -1721,8 +1723,6 @@ static int smc_setsockopt(struct socket *sock, int level, int optname, sk->sk_err = smc->clcsock->sk->sk_err; sk->sk_error_report(sk); } - if (rc) - return rc; if (optlen < sizeof(int)) return -EINVAL; @@ -1730,6 +1730,8 @@ static int smc_setsockopt(struct socket *sock, int level, int optname, return -EFAULT; lock_sock(sk); + if (rc || smc->use_fallback) + goto out; switch (optname) { case TCP_ULP: case TCP_FASTOPEN: @@ -1741,15 +1743,14 @@ static int smc_setsockopt(struct socket *sock, int level, int optname, smc_switch_to_fallback(smc); smc->fallback_rsn = SMC_CLC_DECL_OPTUNSUPP; } else { - if (!smc->use_fallback) - rc = -EINVAL; + rc = -EINVAL; } break; case TCP_NODELAY: if (sk->sk_state != SMC_INIT && sk->sk_state != SMC_LISTEN && sk->sk_state != SMC_CLOSED) { - if (val && !smc->use_fallback) + if (val) mod_delayed_work(system_wq, &smc->conn.tx_work, 0); } @@ -1758,7 +1759,7 @@ static int smc_setsockopt(struct socket *sock, int level, int optname, if (sk->sk_state != SMC_INIT && sk->sk_state != SMC_LISTEN && sk->sk_state != SMC_CLOSED) { - if (!val && !smc->use_fallback) + if (!val) mod_delayed_work(system_wq, &smc->conn.tx_work, 0); } @@ -1769,6 +1770,7 @@ static int smc_setsockopt(struct socket *sock, int level, int optname, default: break; } +out: release_sock(sk); return rc; -- 2.21.0