From nobody Tue Nov 4 15:45:45 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1503968476251380.8729751796143; Mon, 28 Aug 2017 18:01:16 -0700 (PDT) Received: from localhost ([::1]:42143 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dmUu1-0007s1-SE for importer@patchew.org; Mon, 28 Aug 2017 21:01:13 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48652) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dmUCk-0001as-NQ for qemu-devel@nongnu.org; Mon, 28 Aug 2017 20:16:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dmUCh-0005vY-AH for qemu-devel@nongnu.org; Mon, 28 Aug 2017 20:16:30 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:34974 helo=mx0a-001b2d01.pphosted.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dmUCh-0005uM-3J for qemu-devel@nongnu.org; Mon, 28 Aug 2017 20:16:27 -0400 Received: from pps.filterd (m0098413.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id v7T0EBKE017922 for ; Mon, 28 Aug 2017 20:16:26 -0400 Received: from e37.co.us.ibm.com (e37.co.us.ibm.com [32.97.110.158]) by mx0b-001b2d01.pphosted.com with ESMTP id 2cmub2ww5p-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Mon, 28 Aug 2017 20:16:26 -0400 Received: from localhost by e37.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; Mon, 28 Aug 2017 18:16:22 -0600 Received: from b03ledav003.gho.boulder.ibm.com (b03ledav003.gho.boulder.ibm.com [9.17.130.234]) by b03cxnp08027.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id v7T0GLNP65208422; Mon, 28 Aug 2017 17:16:21 -0700 Received: from b03ledav003.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 7F09F6A03C; Mon, 28 Aug 2017 18:16:21 -0600 (MDT) Received: from localhost (unknown [9.80.85.217]) by b03ledav003.gho.boulder.ibm.com (Postfix) with ESMTP id 4B8216A03D; Mon, 28 Aug 2017 18:16:21 -0600 (MDT) From: Michael Roth To: qemu-devel@nongnu.org Date: Mon, 28 Aug 2017 19:14:33 -0500 X-Mailer: git-send-email 2.7.4 In-Reply-To: <1503965694-10794-1-git-send-email-mdroth@linux.vnet.ibm.com> References: <1503965694-10794-1-git-send-email-mdroth@linux.vnet.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 17082900-0024-0000-0000-0000171CE4D5 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00007630; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000226; SDB=6.00909028; UDB=6.00455849; IPR=6.00689279; BA=6.00005557; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00016909; XFM=3.00000015; UTC=2017-08-29 00:16:24 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17082900-0025-0000-0000-00004C7F0560 Message-Id: <1503965694-10794-59-git-send-email-mdroth@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2017-08-28_13:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000 definitions=main-1708290001 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] [fuzzy] X-Received-From: 148.163.158.5 Subject: [Qemu-devel] [PATCH 58/79] nbd: Fully initialize client in case of failed negotiation X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paolo Bonzini , qemu-stable@nongnu.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: Eric Blake If a non-NBD client connects to qemu-nbd, we would end up with a SIGSEGV in nbd_client_put() because we were trying to unregister the client's association to the export, even though we skipped inserting the client into that list. Easy trigger in two terminals: $ qemu-nbd -p 30001 --format=3Draw file $ nmap 127.0.0.1 -p 30001 nmap claims that it thinks it connected to a pago-services1 server (which probably means nmap could be updated to learn the NBD protocol and give a more accurate diagnosis of the open port - but that's not our problem), then terminates immediately, so our call to nbd_negotiate() fails. The fix is to reorder nbd_co_client_start() to ensure that all initialization occurs before we ever try talking to a client in nbd_negotiate(), so that the teardown sequence on negotiation failure doesn't fault while dereferencing a half-initialized object. While debugging this, I also noticed that nbd_update_server_watch() called by nbd_client_closed() was still adding a channel to accept the next client, even when the state was no longer RUNNING. That is fixed by making nbd_can_accept() pay attention to the current state. Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=3D1451614 Signed-off-by: Eric Blake Message-Id: <20170527030421.28366-1-eblake@redhat.com> Signed-off-by: Paolo Bonzini (cherry picked from commit df8ad9f128c15aa0a0ebc7b24e9a22c9775b67af) Signed-off-by: Michael Roth --- nbd/server.c | 8 +++----- qemu-nbd.c | 2 +- 2 files changed, 4 insertions(+), 6 deletions(-) diff --git a/nbd/server.c b/nbd/server.c index 924a1fe..edfda84 100644 --- a/nbd/server.c +++ b/nbd/server.c @@ -1376,16 +1376,14 @@ static coroutine_fn void nbd_co_client_start(void *= opaque) =20 if (exp) { nbd_export_get(exp); + QTAILQ_INSERT_TAIL(&exp->clients, client, next); } + qemu_co_mutex_init(&client->send_lock); + if (nbd_negotiate(data)) { client_close(client); goto out; } - qemu_co_mutex_init(&client->send_lock); - - if (exp) { - QTAILQ_INSERT_TAIL(&exp->clients, client, next); - } =20 nbd_client_receive_next_request(client); =20 diff --git a/qemu-nbd.c b/qemu-nbd.c index e4f00e2..14e7947 100644 --- a/qemu-nbd.c +++ b/qemu-nbd.c @@ -324,7 +324,7 @@ out: =20 static int nbd_can_accept(void) { - return nb_fds < shared; + return state =3D=3D RUNNING && nb_fds < shared; } =20 static void nbd_export_closed(NBDExport *exp) --=20 2.7.4