From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ursula Braun Subject: [PATCH net 3/3] net/smc: move sock lock in smc_ioctl() Date: Wed, 8 Aug 2018 14:13:21 +0200 Message-ID: <20180808121321.516-4-ubraun@linux.ibm.com> References: <20180808121321.516-1-ubraun@linux.ibm.com> Cc: netdev@vger.kernel.org, linux-s390@vger.kernel.org, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, raspl@linux.ibm.com, linux-kernel@vger.kernel.org To: davem@davemloft.net Return-path: Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:54458 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727167AbeHHOc7 (ORCPT ); Wed, 8 Aug 2018 10:32:59 -0400 Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w78CAwGA113993 for ; Wed, 8 Aug 2018 08:13:33 -0400 Received: from e06smtp03.uk.ibm.com (e06smtp03.uk.ibm.com [195.75.94.99]) by mx0a-001b2d01.pphosted.com with ESMTP id 2kqxr941yu-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 08 Aug 2018 08:13:32 -0400 Received: from localhost by e06smtp03.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 8 Aug 2018 13:13:31 +0100 In-Reply-To: <20180808121321.516-1-ubraun@linux.ibm.com> Sender: netdev-owner@vger.kernel.org List-ID: When an SMC socket is connecting it is decided whether fallback to TCP is needed. To avoid races between connect and ioctl move the sock lock before the use_fallback check. Reported-by: syzbot+5b2cece1a8ecb2ca77d8@syzkaller.appspotmail.com Reported-by: syzbot+19557374321ca3710990@syzkaller.appspotmail.com Fixes: 1992d99882af ("net/smc: take sock lock in smc_ioctl()") Signed-off-by: Ursula Braun --- net/smc/af_smc.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index 0ee7721afbe5..e7de5f282722 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -1522,12 +1522,16 @@ static int smc_ioctl(struct socket *sock, unsigned int cmd, smc = smc_sk(sock->sk); conn = &smc->conn; + lock_sock(&smc->sk); if (smc->use_fallback) { - if (!smc->clcsock) + if (!smc->clcsock) { + release_sock(&smc->sk); return -EBADF; - return smc->clcsock->ops->ioctl(smc->clcsock, cmd, arg); + } + answ = smc->clcsock->ops->ioctl(smc->clcsock, cmd, arg); + release_sock(&smc->sk); + return answ; } - lock_sock(&smc->sk); switch (cmd) { case SIOCINQ: /* same as FIONREAD */ if (smc->sk.sk_state == SMC_LISTEN) { -- 2.16.4