From nobody Wed Nov 5 12:00:28 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.zoho.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 1498066997126890.0076338873247; Wed, 21 Jun 2017 10:43:17 -0700 (PDT) Received: from localhost ([::1]:55328 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dNjes-0003Ab-R2 for importer@patchew.org; Wed, 21 Jun 2017 13:43:14 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54067) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dNjdk-0002UV-B8 for qemu-devel@nongnu.org; Wed, 21 Jun 2017 13:42:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dNjdj-0003qP-EI for qemu-devel@nongnu.org; Wed, 21 Jun 2017 13:42:04 -0400 Received: from 14.mo5.mail-out.ovh.net ([188.165.51.82]:46925) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dNjdj-0003pr-7c for qemu-devel@nongnu.org; Wed, 21 Jun 2017 13:42:03 -0400 Received: from player695.ha.ovh.net (b9.ovh.net [213.186.33.59]) by mo5.mail-out.ovh.net (Postfix) with ESMTP id 2D8101085C4 for ; Wed, 21 Jun 2017 19:42:02 +0200 (CEST) Received: from bahia.lan (gar31-1-82-66-74-139.fbx.proxad.net [82.66.74.139]) (Authenticated sender: groug@kaod.org) by player695.ha.ovh.net (Postfix) with ESMTPA id E5E19460073; Wed, 21 Jun 2017 19:41:58 +0200 (CEST) From: Greg Kurz To: qemu-devel@nongnu.org Date: Wed, 21 Jun 2017 19:41:58 +0200 Message-ID: <149806691869.3840.9613299727376965070.stgit@bahia.lan> In-Reply-To: <149806690313.3840.13274158676579302242.stgit@bahia.lan> References: <149806690313.3840.13274158676579302242.stgit@bahia.lan> User-Agent: StGit/0.17.1-20-gc0b1b-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Ovh-Tracer-Id: 12675944105149962673 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrfeeljedrledtgdduudelucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuqfggjfdpvefjgfevmfevgfenuceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddm X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 188.165.51.82 Subject: [Qemu-devel] [PATCH v3 1/4] virtio-9p: record element after sanity checks 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: Stefano Stabellini , Greg Kurz , "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 If the guest sends a malformed request, we end up with a dangling pointer in V9fsVirtioState. This doesn't seem to cause any bug, but let's remove this side effect anyway. Signed-off-by: Greg Kurz Reviewed-by: Michael S. Tsirkin --- hw/9pfs/virtio-9p-device.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c index 245abd8aaef1..3380bfc0c551 100644 --- a/hw/9pfs/virtio-9p-device.c +++ b/hw/9pfs/virtio-9p-device.c @@ -61,7 +61,6 @@ static void handle_9p_output(VirtIODevice *vdev, VirtQueu= e *vq) } QEMU_BUILD_BUG_ON(sizeof(out) !=3D 7); =20 - v->elems[pdu->idx] =3D elem; len =3D iov_to_buf(elem->out_sg, elem->out_num, 0, &out, sizeof(out)); if (len !=3D sizeof(out)) { @@ -70,6 +69,8 @@ static void handle_9p_output(VirtIODevice *vdev, VirtQueu= e *vq) goto out_free_req; } =20 + v->elems[pdu->idx] =3D elem; + pdu_submit(pdu, &out); } =20 From nobody Wed Nov 5 12:00:28 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.zoho.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 149806715430454.529727922240454; Wed, 21 Jun 2017 10:45:54 -0700 (PDT) Received: from localhost ([::1]:55344 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dNjhR-00051I-2l for importer@patchew.org; Wed, 21 Jun 2017 13:45:53 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54111) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dNjdv-0002dd-Nr for qemu-devel@nongnu.org; Wed, 21 Jun 2017 13:42:16 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dNjds-0003vd-Bd for qemu-devel@nongnu.org; Wed, 21 Jun 2017 13:42:15 -0400 Received: from 4.mo5.mail-out.ovh.net ([178.33.111.247]:36306) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dNjds-0003ur-4m for qemu-devel@nongnu.org; Wed, 21 Jun 2017 13:42:12 -0400 Received: from player695.ha.ovh.net (b9.ovh.net [213.186.33.59]) by mo5.mail-out.ovh.net (Postfix) with ESMTP id AEC65107C37 for ; Wed, 21 Jun 2017 19:42:10 +0200 (CEST) Received: from bahia.lan (gar31-1-82-66-74-139.fbx.proxad.net [82.66.74.139]) (Authenticated sender: groug@kaod.org) by player695.ha.ovh.net (Postfix) with ESMTPA id 70411460073; Wed, 21 Jun 2017 19:42:07 +0200 (CEST) From: Greg Kurz To: qemu-devel@nongnu.org Date: Wed, 21 Jun 2017 19:42:07 +0200 Message-ID: <149806692721.3840.2211779486273110064.stgit@bahia.lan> In-Reply-To: <149806690313.3840.13274158676579302242.stgit@bahia.lan> References: <149806690313.3840.13274158676579302242.stgit@bahia.lan> User-Agent: StGit/0.17.1-20-gc0b1b-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Ovh-Tracer-Id: 12678195903672129969 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrfeeljedrledtgdduudelucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuqfggjfdpvefjgfevmfevgfenuceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddm X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 178.33.111.247 Subject: [Qemu-devel] [PATCH v3 2/4] virtio-9p: message header is 7-byte long 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: Stefano Stabellini , Greg Kurz , "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 The 9p spec at http://man.cat-v.org/plan_9/5/intro reads: "Each 9P message begins with a four-byte size field specify- ing the length in bytes of the complete message including the four bytes of the size field itself. The next byte is the message type, one of the constants in the enumeration in the include file . The next two bytes are an iden- tifying tag, described below." ie, each message starts with a 7-byte long header. The core 9P code already assumes this pretty much everywhere. This patch does the following: - makes the assumption explicit in the common 9p.h header, since it isn't related to the transport - open codes the header size in handle_9p_output() and hardens the sanity check on the space needed for the reply message Signed-off-by: Greg Kurz --- hw/9pfs/9p.h | 5 +++++ hw/9pfs/virtio-9p-device.c | 8 +++----- 2 files changed, 8 insertions(+), 5 deletions(-) diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h index c886ba78d2ee..aac1b0b2ce3d 100644 --- a/hw/9pfs/9p.h +++ b/hw/9pfs/9p.h @@ -124,6 +124,11 @@ typedef struct { uint8_t id; uint16_t tag_le; } QEMU_PACKED P9MsgHeader; +/* According to the specification, 9p messages start with a 7-byte header. + * Since most of the code uses this header size in literal form, we must be + * sure this is indeed the case. + */ +QEMU_BUILD_BUG_ON(sizeof(P9MsgHeader) !=3D 7); =20 struct V9fsPDU { diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c index 3380bfc0c551..1a68c1622d3a 100644 --- a/hw/9pfs/virtio-9p-device.c +++ b/hw/9pfs/virtio-9p-device.c @@ -53,17 +53,15 @@ static void handle_9p_output(VirtIODevice *vdev, VirtQu= eue *vq) goto out_free_pdu; } =20 - if (elem->in_num =3D=3D 0) { + if (iov_size(elem->in_sg, elem->in_num) < 7) { virtio_error(vdev, "The guest sent a VirtFS request without space fo= r " "the reply"); goto out_free_req; } - QEMU_BUILD_BUG_ON(sizeof(out) !=3D 7); =20 - len =3D iov_to_buf(elem->out_sg, elem->out_num, 0, - &out, sizeof(out)); - if (len !=3D sizeof(out)) { + len =3D iov_to_buf(elem->out_sg, elem->out_num, 0, &out, 7); + if (len !=3D 7) { virtio_error(vdev, "The guest sent a malformed VirtFS request:= " "header size is %zd, should be 7", len); goto out_free_req; From nobody Wed Nov 5 12:00:28 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.zoho.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 1498067220110141.23668114609438; Wed, 21 Jun 2017 10:47:00 -0700 (PDT) Received: from localhost ([::1]:55347 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dNjiU-0005Y5-T6 for importer@patchew.org; Wed, 21 Jun 2017 13:46:58 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54186) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dNje4-0002lf-Lq for qemu-devel@nongnu.org; Wed, 21 Jun 2017 13:42:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dNje1-00040l-9t for qemu-devel@nongnu.org; Wed, 21 Jun 2017 13:42:24 -0400 Received: from 3.mo5.mail-out.ovh.net ([46.105.40.108]:60384) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dNje0-0003zr-Vq for qemu-devel@nongnu.org; Wed, 21 Jun 2017 13:42:21 -0400 Received: from player695.ha.ovh.net (b9.ovh.net [213.186.33.59]) by mo5.mail-out.ovh.net (Postfix) with ESMTP id 7D595107C37 for ; Wed, 21 Jun 2017 19:42:19 +0200 (CEST) Received: from bahia.lan (gar31-1-82-66-74-139.fbx.proxad.net [82.66.74.139]) (Authenticated sender: groug@kaod.org) by player695.ha.ovh.net (Postfix) with ESMTPA id F150F460073; Wed, 21 Jun 2017 19:42:15 +0200 (CEST) From: Greg Kurz To: qemu-devel@nongnu.org Date: Wed, 21 Jun 2017 19:42:15 +0200 Message-ID: <149806693574.3840.9096786036333390842.stgit@bahia.lan> In-Reply-To: <149806690313.3840.13274158676579302242.stgit@bahia.lan> References: <149806690313.3840.13274158676579302242.stgit@bahia.lan> User-Agent: StGit/0.17.1-20-gc0b1b-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Ovh-Tracer-Id: 12680729177532307889 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrfeeljedrledtgdduudelucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuqfggjfdpvefjgfevmfevgfenuceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddm X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 46.105.40.108 Subject: [Qemu-devel] [PATCH v3 3/4] virtio-9p: break device if buffers are misconfigured 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: Stefano Stabellini , Greg Kurz , "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 The 9P protocol is transport agnostic: if the guest misconfigured the buffers, the best we can do is to set the broken flag on the device. We check if the transport isn't broken already to avoid printing extra error messages. Signed-off-by: Greg Kurz --- hw/9pfs/9p.c | 2 +- hw/9pfs/9p.h | 2 +- hw/9pfs/virtio-9p-device.c | 45 ++++++++++++++++++++++++++++++++++++++++= ---- hw/9pfs/xen-9p-backend.c | 3 ++- 4 files changed, 45 insertions(+), 7 deletions(-) diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c index 96d268334865..da0d6da65b45 100644 --- a/hw/9pfs/9p.c +++ b/hw/9pfs/9p.c @@ -1664,7 +1664,7 @@ static void v9fs_init_qiov_from_pdu(QEMUIOVector *qio= v, V9fsPDU *pdu, unsigned int niov; =20 if (is_write) { - pdu->s->transport->init_out_iov_from_pdu(pdu, &iov, &niov); + pdu->s->transport->init_out_iov_from_pdu(pdu, &iov, &niov, size + = skip); } else { pdu->s->transport->init_in_iov_from_pdu(pdu, &iov, &niov, size + s= kip); } diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h index aac1b0b2ce3d..d1cfeaf10e4f 100644 --- a/hw/9pfs/9p.h +++ b/hw/9pfs/9p.h @@ -363,7 +363,7 @@ struct V9fsTransport { void (*init_in_iov_from_pdu)(V9fsPDU *pdu, struct iovec **piov, unsigned int *pniov, size_t size); void (*init_out_iov_from_pdu)(V9fsPDU *pdu, struct iovec **piov, - unsigned int *pniov); + unsigned int *pniov, size_t size); void (*push_and_notify)(V9fsPDU *pdu); }; =20 diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c index 1a68c1622d3a..873f42e24818 100644 --- a/hw/9pfs/virtio-9p-device.c +++ b/hw/9pfs/virtio-9p-device.c @@ -146,8 +146,18 @@ static ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_= t offset, V9fsState *s =3D pdu->s; V9fsVirtioState *v =3D container_of(s, V9fsVirtioState, state); VirtQueueElement *elem =3D v->elems[pdu->idx]; + int ret; =20 - return v9fs_iov_vmarshal(elem->in_sg, elem->in_num, offset, 1, fmt, ap= ); + ret =3D v9fs_iov_vmarshal(elem->in_sg, elem->in_num, offset, 1, fmt, a= p); + if (ret < 0) { + VirtIODevice *vdev =3D VIRTIO_DEVICE(v); + + if (!vdev->broken) { + virtio_error(vdev, "Failed to encode VirtFS reply type %d", + pdu->id + 1); + } + } + return ret; } =20 static ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset, @@ -156,28 +166,55 @@ static ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, si= ze_t offset, V9fsState *s =3D pdu->s; V9fsVirtioState *v =3D container_of(s, V9fsVirtioState, state); VirtQueueElement *elem =3D v->elems[pdu->idx]; + int ret; =20 - return v9fs_iov_vunmarshal(elem->out_sg, elem->out_num, offset, 1, fmt= , ap); + ret =3D v9fs_iov_vunmarshal(elem->out_sg, elem->out_num, offset, 1, fm= t, ap); + if (ret < 0) { + VirtIODevice *vdev =3D VIRTIO_DEVICE(v); + + if (!vdev->broken) { + virtio_error(vdev, "Failed to decode VirtFS request type %d", + pdu->id); + } + } + return ret; } =20 -/* The size parameter is used by other transports. Do not drop it. */ static void virtio_init_in_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov, unsigned int *pniov, size_t size) { V9fsState *s =3D pdu->s; V9fsVirtioState *v =3D container_of(s, V9fsVirtioState, state); VirtQueueElement *elem =3D v->elems[pdu->idx]; + size_t buf_size =3D iov_size(elem->in_sg, elem->in_num); + + if (buf_size < size) { + VirtIODevice *vdev =3D VIRTIO_DEVICE(v); + + virtio_error(vdev, + "VirtFS reply type %d needs %zu bytes, buffer has %zu= ", + pdu->id + 1, size, buf_size); + } =20 *piov =3D elem->in_sg; *pniov =3D elem->in_num; } =20 static void virtio_init_out_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov, - unsigned int *pniov) + unsigned int *pniov, size_t size) { V9fsState *s =3D pdu->s; V9fsVirtioState *v =3D container_of(s, V9fsVirtioState, state); VirtQueueElement *elem =3D v->elems[pdu->idx]; + size_t buf_size =3D iov_size(elem->out_sg, elem->out_num); + + if (buf_size < size) { + VirtIODevice *vdev =3D VIRTIO_DEVICE(v); + + virtio_error(vdev, + "VirtFS request type %d needs %zu bytes, buffer has %= zu", + pdu->id, size, buf_size); + } =20 *piov =3D elem->out_sg; *pniov =3D elem->out_num; diff --git a/hw/9pfs/xen-9p-backend.c b/hw/9pfs/xen-9p-backend.c index 922cc967be63..a82cf817fe45 100644 --- a/hw/9pfs/xen-9p-backend.c +++ b/hw/9pfs/xen-9p-backend.c @@ -147,7 +147,8 @@ static ssize_t xen_9pfs_pdu_vunmarshal(V9fsPDU *pdu, =20 static void xen_9pfs_init_out_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov, - unsigned int *pniov) + unsigned int *pniov, + size_t size) { Xen9pfsDev *xen_9pfs =3D container_of(pdu->s, Xen9pfsDev, state); Xen9pfsRing *ring =3D &xen_9pfs->rings[pdu->tag % xen_9pfs->num_rings]; From nobody Wed Nov 5 12:00:28 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.zoho.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 1498067092975574.2721399584578; Wed, 21 Jun 2017 10:44:52 -0700 (PDT) Received: from localhost ([::1]:55335 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dNjgR-0004FB-KP for importer@patchew.org; Wed, 21 Jun 2017 13:44:51 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54241) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dNjeD-0002r8-8B for qemu-devel@nongnu.org; Wed, 21 Jun 2017 13:42:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dNje9-00045Y-Rn for qemu-devel@nongnu.org; Wed, 21 Jun 2017 13:42:33 -0400 Received: from 6.mo5.mail-out.ovh.net ([178.32.119.138]:34164) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dNje9-00044v-KM for qemu-devel@nongnu.org; Wed, 21 Jun 2017 13:42:29 -0400 Received: from player695.ha.ovh.net (b9.ovh.net [213.186.33.59]) by mo5.mail-out.ovh.net (Postfix) with ESMTP id 08FC2108541 for ; Wed, 21 Jun 2017 19:42:28 +0200 (CEST) Received: from bahia.lan (gar31-1-82-66-74-139.fbx.proxad.net [82.66.74.139]) (Authenticated sender: groug@kaod.org) by player695.ha.ovh.net (Postfix) with ESMTPA id C0741460076; Wed, 21 Jun 2017 19:42:24 +0200 (CEST) From: Greg Kurz To: qemu-devel@nongnu.org Date: Wed, 21 Jun 2017 19:42:24 +0200 Message-ID: <149806694454.3840.8657784311452513680.stgit@bahia.lan> In-Reply-To: <149806690313.3840.13274158676579302242.stgit@bahia.lan> References: <149806690313.3840.13274158676579302242.stgit@bahia.lan> User-Agent: StGit/0.17.1-20-gc0b1b-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Ovh-Tracer-Id: 12683262450584754609 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrfeeljedrledtgdduudelucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuqfggjfdpvefjgfevmfevgfenuceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddm X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 178.32.119.138 Subject: [Qemu-devel] [PATCH v3 4/4] 9pfs: handle transport errors in pdu_complete() 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: Stefano Stabellini , Greg Kurz , "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Contrary to what is written in the comment, a buggy guest can misconfigure the transport buffers and pdu_marshal() may return an error. If this ever happens, it is up to the transport layer to handle the situation (9P is transport agnostic). This fixes Coverity issue CID1348518. Signed-off-by: Greg Kurz --- hw/9pfs/9p.c | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c index da0d6da65b45..f7871e6f3e5a 100644 --- a/hw/9pfs/9p.c +++ b/hw/9pfs/9p.c @@ -624,15 +624,11 @@ void pdu_free(V9fsPDU *pdu) QLIST_INSERT_HEAD(&s->free_list, pdu, next); } =20 -/* - * We don't do error checking for pdu_marshal/unmarshal here - * because we always expect to have enough space to encode - * error details - */ static void coroutine_fn pdu_complete(V9fsPDU *pdu, ssize_t len) { int8_t id =3D pdu->id + 1; /* Response */ V9fsState *s =3D pdu->s; + int ret; =20 if (len < 0) { int err =3D -len; @@ -644,11 +640,19 @@ static void coroutine_fn pdu_complete(V9fsPDU *pdu, s= size_t len) str.data =3D strerror(err); str.size =3D strlen(str.data); =20 - len +=3D pdu_marshal(pdu, len, "s", &str); + ret =3D pdu_marshal(pdu, len, "s", &str); + if (ret < 0) { + goto out_notify; + } + len +=3D ret; id =3D P9_RERROR; } =20 - len +=3D pdu_marshal(pdu, len, "d", err); + ret =3D pdu_marshal(pdu, len, "d", err); + if (ret < 0) { + goto out_notify; + } + len +=3D ret; =20 if (s->proto_version =3D=3D V9FS_PROTO_2000L) { id =3D P9_RLERROR; @@ -657,12 +661,15 @@ static void coroutine_fn pdu_complete(V9fsPDU *pdu, s= size_t len) } =20 /* fill out the header */ - pdu_marshal(pdu, 0, "dbw", (int32_t)len, id, pdu->tag); + if (pdu_marshal(pdu, 0, "dbw", (int32_t)len, id, pdu->tag) < 0) { + goto out_notify; + } =20 /* keep these in sync */ pdu->size =3D len; pdu->id =3D id; =20 +out_notify: pdu->s->transport->push_and_notify(pdu); =20 /* Now wakeup anybody waiting in flush for this request */