From nobody Wed Nov 5 11:39:57 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 1498200430958780.9706158335883; Thu, 22 Jun 2017 23:47:10 -0700 (PDT) Received: from localhost ([::1]:33820 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dOIN3-0002zR-IM for importer@patchew.org; Fri, 23 Jun 2017 02:47:09 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47432) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dOILF-0001p1-1b for qemu-devel@nongnu.org; Fri, 23 Jun 2017 02:45:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dOILA-00080I-Jz for qemu-devel@nongnu.org; Fri, 23 Jun 2017 02:45:17 -0400 Received: from 2.mo5.mail-out.ovh.net ([178.33.109.111]:55726) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dOILA-0007zo-Dd for qemu-devel@nongnu.org; Fri, 23 Jun 2017 02:45:12 -0400 Received: from player695.ha.ovh.net (b9.ovh.net [213.186.33.59]) by mo5.mail-out.ovh.net (Postfix) with ESMTP id 05A25107509 for ; Fri, 23 Jun 2017 08:45:11 +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 BF646460075; Fri, 23 Jun 2017 08:45:07 +0200 (CEST) From: Greg Kurz To: qemu-devel@nongnu.org Date: Fri, 23 Jun 2017 08:45:07 +0200 Message-ID: <149820030753.7187.17749668632776032356.stgit@bahia.lan> In-Reply-To: <149820029273.7187.14110849422638329192.stgit@bahia.lan> References: <149820029273.7187.14110849422638329192.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: 13327840148472830385 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrfeeljedrleefgdduudekucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuqfggjfdpvefjgfevmfevgfenuceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddm X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 178.33.109.111 Subject: [Qemu-devel] [PATCH v4 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 11:39:57 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 1498200506583549.1209744740869; Thu, 22 Jun 2017 23:48:26 -0700 (PDT) Received: from localhost ([::1]:33824 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dOIOH-0004dc-Cq for importer@patchew.org; Fri, 23 Jun 2017 02:48:25 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47469) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dOILO-0001vo-9B for qemu-devel@nongnu.org; Fri, 23 Jun 2017 02:45:27 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dOILK-00083k-9I for qemu-devel@nongnu.org; Fri, 23 Jun 2017 02:45:26 -0400 Received: from 7.mo5.mail-out.ovh.net ([178.32.124.100]:57136) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dOILK-000833-1Z for qemu-devel@nongnu.org; Fri, 23 Jun 2017 02:45:22 -0400 Received: from player695.ha.ovh.net (b9.ovh.net [213.186.33.59]) by mo5.mail-out.ovh.net (Postfix) with ESMTP id 89575107842 for ; Fri, 23 Jun 2017 08:45:20 +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 4D035460075; Fri, 23 Jun 2017 08:45:17 +0200 (CEST) From: Greg Kurz To: qemu-devel@nongnu.org Date: Fri, 23 Jun 2017 08:45:16 +0200 Message-ID: <149820031604.7187.14987200901766883821.stgit@bahia.lan> In-Reply-To: <149820029273.7187.14110849422638329192.stgit@bahia.lan> References: <149820029273.7187.14110849422638329192.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: 13330654897788328369 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrfeeljedrleefgdduudekucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuqfggjfdpvefjgfevmfevgfenuceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddm X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 178.32.124.100 Subject: [Qemu-devel] [PATCH v4 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 11:39:57 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 1498200528363425.3250312678583; Thu, 22 Jun 2017 23:48:48 -0700 (PDT) Received: from localhost ([::1]:33825 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dOIOb-0004sR-UF for importer@patchew.org; Fri, 23 Jun 2017 02:48:45 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47509) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dOILX-00024z-SU for qemu-devel@nongnu.org; Fri, 23 Jun 2017 02:45:37 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dOILS-00087E-UP for qemu-devel@nongnu.org; Fri, 23 Jun 2017 02:45:35 -0400 Received: from 3.mo5.mail-out.ovh.net ([46.105.40.108]:41556) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dOILS-00086n-L9 for qemu-devel@nongnu.org; Fri, 23 Jun 2017 02:45:30 -0400 Received: from player695.ha.ovh.net (b9.ovh.net [213.186.33.59]) by mo5.mail-out.ovh.net (Postfix) with ESMTP id 1AAA0108243 for ; Fri, 23 Jun 2017 08:45:29 +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 CC7BD460075; Fri, 23 Jun 2017 08:45:25 +0200 (CEST) From: Greg Kurz To: qemu-devel@nongnu.org Date: Fri, 23 Jun 2017 08:45:25 +0200 Message-ID: <149820032558.7187.9574922678907797880.stgit@bahia.lan> In-Reply-To: <149820029273.7187.14110849422638329192.stgit@bahia.lan> References: <149820029273.7187.14110849422638329192.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: 13333188173404740017 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrfeeljedrleefgdduudekucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuqfggjfdpvefjgfevmfevgfenuceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddm 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 v4 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. Since virtio_pdu_vmarshal() may be called by several active PDUs, we check if the transport isn't broken already to avoid printing extra error messages. Signed-off-by: Greg Kurz --- v4: - update changelog and add comment to explain why we check vdev->broken in virtio_pdu_vmarshal() - dropped uneeded vdev->broken check in virtio_pdu_vunmarshal() --- hw/9pfs/9p.c | 2 +- hw/9pfs/9p.h | 2 +- hw/9pfs/virtio-9p-device.c | 48 +++++++++++++++++++++++++++++++++++++++-= ---- hw/9pfs/xen-9p-backend.c | 3 ++- 4 files changed, 47 insertions(+), 8 deletions(-) diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c index a0ae98f7ca6f..8e5cac71eb60 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..ed9e4817a26c 100644 --- a/hw/9pfs/virtio-9p-device.c +++ b/hw/9pfs/virtio-9p-device.c @@ -146,8 +146,22 @@ 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]; - - return v9fs_iov_vmarshal(elem->in_sg, elem->in_num, offset, 1, fmt, ap= ); + int ret; + + 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); + + /* Any active PDU may try to send something back to the client wit= hout + * knowing if the transport is broken or not. This could result in + * MAX_REQ - 1 (ie, 127) extra error messages being printed. + */ + 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 +170,52 @@ 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); + + 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 11:39:57 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 1498200558720404.00880101204325; Thu, 22 Jun 2017 23:49:18 -0700 (PDT) Received: from localhost ([::1]:33826 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dOIP7-0005HZ-E0 for importer@patchew.org; Fri, 23 Jun 2017 02:49:17 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47570) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dOILf-0002CM-P5 for qemu-devel@nongnu.org; Fri, 23 Jun 2017 02:45:48 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dOILb-0008AU-Ap for qemu-devel@nongnu.org; Fri, 23 Jun 2017 02:45:43 -0400 Received: from 14.mo5.mail-out.ovh.net ([188.165.51.82]:35897) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dOILb-00089f-2N for qemu-devel@nongnu.org; Fri, 23 Jun 2017 02:45:39 -0400 Received: from player695.ha.ovh.net (b9.ovh.net [213.186.33.59]) by mo5.mail-out.ovh.net (Postfix) with ESMTP id 9D0A2107B7A for ; Fri, 23 Jun 2017 08:45:37 +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 6125546006E; Fri, 23 Jun 2017 08:45:34 +0200 (CEST) From: Greg Kurz To: qemu-devel@nongnu.org Date: Fri, 23 Jun 2017 08:45:34 +0200 Message-ID: <149820033413.7187.1250602964263131431.stgit@bahia.lan> In-Reply-To: <149820029273.7187.14110849422638329192.stgit@bahia.lan> References: <149820029273.7187.14110849422638329192.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: 13335439975094524337 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrfeeljedrleefgdduudekucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuqfggjfdpvefjgfevmfevgfenuceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddm 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 v4 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 8e5cac71eb60..6c92bad5b3b4 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 */