From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42150) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VnsnW-0006Z8-NV for qemu-devel@nongnu.org; Tue, 03 Dec 2013 11:26:12 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VnsnQ-0006va-O3 for qemu-devel@nongnu.org; Tue, 03 Dec 2013 11:26:06 -0500 Date: Tue, 3 Dec 2013 18:29:21 +0200 From: "Michael S. Tsirkin" Message-ID: <1386087086-3691-23-git-send-email-mst@redhat.com> References: <1386087086-3691-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1386087086-3691-1-git-send-email-mst@redhat.com> Subject: [Qemu-devel] [PATCH 22/23] virtio-scsi: fix buffer overrun on invalid state load List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Paolo Bonzini , qemu-stable@nongnu.org, Anthony Liguori CVE-2013-4542 hw/scsi/scsi-bus.c invokes load_request. virtio_scsi_load_request does: qemu_get_buffer(f, (unsigned char *)&req->elem, sizeof(req->elem)); this probably can make elem invalid, for example, make in_num or out_num huge, then: virtio_scsi_parse_req(s, vs->cmd_vqs[n], req); will do: if (req->elem.out_num > 1) { qemu_sgl_init_external(req, &req->elem.out_sg[1], &req->elem.out_addr[1], req->elem.out_num - 1); } else { qemu_sgl_init_external(req, &req->elem.in_sg[1], &req->elem.in_addr[1], req->elem.in_num - 1); } and this will access out of array bounds. suggested patch: Signed-off-by: Michael S. Tsirkin --- hw/scsi/virtio-scsi.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/hw/scsi/virtio-scsi.c b/hw/scsi/virtio-scsi.c index 26d95a1..51cc929 100644 --- a/hw/scsi/virtio-scsi.c +++ b/hw/scsi/virtio-scsi.c @@ -147,6 +147,8 @@ static void *virtio_scsi_load_request(QEMUFile *f, SCSIRequest *sreq) qemu_get_be32s(f, &n); assert(n < vs->conf.num_queues); qemu_get_buffer(f, (unsigned char *)&req->elem, sizeof(req->elem)); + assert(req->elem.in_num <= ARRAY_SIZE(req->elem.in_sg)); + assert(req->elem.out_num <= ARRAY_SIZE(req->elem.out_sg)); virtio_scsi_parse_req(s, vs->cmd_vqs[n], req); scsi_req_ref(sreq); -- MST