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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 34A94C2D0C6 for ; Fri, 27 Dec 2019 17:43:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1022122522 for ; Fri, 27 Dec 2019 17:43:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577468608; bh=gfIGQp34RVhSZnYCRMgdzjv+nUlxz9OyufQbnXilM/g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=LOZyAQ1kj1XIwjxa7KWoKOAeUMjC1MTQD+FeTSR8He2Nh2+9yl0r7rhDmub72U+hK UCGHBesRXe300E1us8y07o0Vxy7ljRTjnNHfPTErq2nrmHDpJ8saT5PiuDPj2H4HGf laA9g1rqA12noX8XVJ/Rcq2kJsE2C1+s1DgZZzY0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727820AbfL0Rn0 (ORCPT ); Fri, 27 Dec 2019 12:43:26 -0500 Received: from mail.kernel.org ([198.145.29.99]:40660 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728167AbfL0RnQ (ORCPT ); Fri, 27 Dec 2019 12:43:16 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 2F5B024654; Fri, 27 Dec 2019 17:43:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577468596; bh=gfIGQp34RVhSZnYCRMgdzjv+nUlxz9OyufQbnXilM/g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=r1VPxnSe1OUI1O7HkaE0N3xnMJpRRzeeGSgzQ88gBL3MzYp1ZwqWOTbuAVIFP74Ap lXc/BA1KfQWJPqy5kuFli5Eaelyjhen2r6WndBWRnx2PiYa+QzUxj6eZX+QjWrg7JK E80BLzk5USgWqWEqCefva2FUtq9hvj9/4sVD02DY= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ursula Braun , syzbot+96d3f9ff6a86d37e44c8@syzkaller.appspotmail.com, Karsten Graul , Jakub Kicinski , Sasha Levin , linux-s390@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 117/187] net/smc: add fallback check to connect() Date: Fri, 27 Dec 2019 12:39:45 -0500 Message-Id: <20191227174055.4923-117-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20191227174055.4923-1-sashal@kernel.org> References: <20191227174055.4923-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ursula Braun [ Upstream commit 86434744fedf0cfe07a9eee3f4632c0e25c1d136 ] 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 Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- 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 737b49909a7a..6a6d3b2aa5a9 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -854,6 +854,8 @@ 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; @@ -1716,8 +1718,6 @@ 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; @@ -1725,6 +1725,8 @@ 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: @@ -1736,15 +1738,14 @@ 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); } @@ -1753,7 +1754,7 @@ 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); } @@ -1764,6 +1765,7 @@ static int smc_setsockopt(struct socket *sock, int level, int optname, default: break; } +out: release_sock(sk); return rc; -- 2.20.1