From: Michael Roth <mdroth@linux.vnet.ibm.com>
Date: Wed, 4 Mar 2015 16:57:56 +0000 (+0000)
Subject: virtio: avoid buffer overrun on incoming migration
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=501d7f8faa05597ebb0bb54dea7d323967fa449b;p=qemu-upstream-4.2-testing.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.c b/hw/virtio.c
index 068c24dc1..7fddfe9c7 100644
--- a/hw/virtio.c
+++ b/hw/virtio.c
@@ -799,6 +799,9 @@ 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) {