From: Michael Roth <mdroth@linux.vnet.ibm.com>
Date: Thu, 3 Apr 2014 16:51:46 +0000 (+0300)
Subject: virtio: avoid buffer overrun on incoming migration
X-Git-Tag: qemu-xen-4.4.3-rc1~36
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=d961961ec93227065fd343f5725a1ff756d6981f;p=qemu-xen.git

virtio: avoid buffer overrun on incoming migration

CVE-2013-6399

vdev->queue_sel is read from the wire, and later used in the
emulation code as an index into vdev->vq[]. If the value of
vdev->queue_sel exceeds the length of vdev->vq[], currently
allocated to be VIRTIO_PCI_QUEUE_MAX elements, subsequent PIO
operations such as VIRTIO_PCI_QUEUE_PFN can be used to overrun
the buffer with arbitrary data originating from the source.

Fix this by failing migration if the value from the wire exceeds
VIRTIO_PCI_QUEUE_MAX.

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Juan Quintela <quintela@redhat.com>
---

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 423b446462..3c59631f5b 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -910,6 +910,9 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f)
     qemu_get_8s(f, &vdev->status);
     qemu_get_8s(f, &vdev->isr);
     qemu_get_be16s(f, &vdev->queue_sel);
+    if (vdev->queue_sel >= VIRTIO_PCI_QUEUE_MAX) {
+        return -1;
+    }
     qemu_get_be32s(f, &features);
 
     if (virtio_set_features(vdev, features) < 0) {