From 246b73b5e55eedcc30a213a685a46ad2f117862e Mon Sep 17 00:00:00 2001
From: Michael S. Tsirkin <mst@redhat.com>
Date: Wed, 14 May 2014 08:07:49 +0200
Subject: [PATCH 04/30] virtio: out-of-bounds buffer write on invalid state load

RH-Author: Michael S. Tsirkin <mst@redhat.com>
Message-id: <1400054498-4366-4-git-send-email-mst@redhat.com>
Patchwork-id: 58842
O-Subject: [PATCH qemu-kvm RHEL7.0] virtio: out-of-bounds buffer write on invalid state load
Bugzilla: 1095694
RH-Acked-by: Dr. David Alan Gilbert (git) <dgilbert@redhat.com>
RH-Acked-by: Juan Quintela <quintela@redhat.com>
RH-Acked-by: Vlad Yasevich <vyasevic@redhat.com>
RH-Acked-by: Xiao Wang <jasowang@redhat.com>

CVE-2013-4151 QEMU 1.0 out-of-bounds buffer write in
virtio_load@hw/virtio/virtio.c

So we have this code since way back when:

    num = qemu_get_be32(f);

    for (i = 0; i < num; i++) {
        vdev->vq[i].vring.num = qemu_get_be32(f);

array of vqs has size VIRTIO_PCI_QUEUE_MAX, so
on invalid input this will write beyond end of buffer.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
(cherry picked from commit cc45995294b92d95319b4782750a3580cabdbc0c)

Tested: lightly on developer's box
Brew build: http://brewweb.devel.redhat.com/brew/taskinfo?taskID=7450401
Bugzilla: 1095694
---
 hw/virtio/virtio.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 hw/virtio/virtio.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index b5bb0b6..070d64e 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -851,7 +851,8 @@ int virtio_set_features(VirtIODevice *vdev, uint32_t val)
 
 int virtio_load(VirtIODevice *vdev, QEMUFile *f)
 {
-    int num, i, ret;
+    int i, ret;
+    uint32_t num;
     uint32_t features;
     uint32_t supported_features;
     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
@@ -879,6 +880,11 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f)
 
     num = qemu_get_be32(f);
 
+    if (num > VIRTIO_PCI_QUEUE_MAX) {
+        error_report("Invalid number of PCI queues: 0x%x", num);
+        return -1;
+    }
+
     for (i = 0; i < num; i++) {
         vdev->vq[i].vring.num = qemu_get_be32(f);
         vdev->vq[i].pa = qemu_get_be64(f);
-- 
1.7.1