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From caaae46a54a676914cc3725b7fe892874825302d Mon Sep 17 00:00:00 2001
From: Michael S. Tsirkin <mst@redhat.com>
Date: Wed, 14 May 2014 08:32:21 +0200
Subject: [PATCH 15/31] virtio: validate config_len on load

RH-Author: Michael S. Tsirkin <mst@redhat.com>
Message-id: <1400056285-6688-17-git-send-email-mst@redhat.com>
Patchwork-id: 58861
O-Subject: [PATCH qemu-kvm RHEL7.1] virtio: validate config_len on load
Bugzilla: 1095783
RH-Acked-by: Dr. David Alan Gilbert (git) <dgilbert@redhat.com>
RH-Acked-by: Juan Quintela <quintela@redhat.com>
RH-Acked-by: Xiao Wang <jasowang@redhat.com>

Malformed input can have config_len in migration stream
exceed the array size allocated on destination, the
result will be heap overflow.

To fix, that config_len matches on both sides.

CVE-2014-0182

Reported-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
(cherry picked from commit a890a2f9137ac3cf5b607649e66a6f3a5512d8dc)

Tested: lightly on developer's box
Brew build: http://brewweb.devel.redhat.com/brew/taskinfo?taskID=7452039
Bugzilla:1095783
---
 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 9600a12..686dfbb 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -852,6 +852,7 @@ int virtio_set_features(VirtIODevice *vdev, uint32_t val)
 int virtio_load(VirtIODevice *vdev, QEMUFile *f)
 {
     int i, ret;
+    int32_t config_len;
     uint32_t num;
     uint32_t features;
     uint32_t supported_features;
@@ -878,7 +879,12 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f)
                      features, supported_features);
         return -1;
     }
-    vdev->config_len = qemu_get_be32(f);
+    config_len = qemu_get_be32(f);
+    if (config_len != vdev->config_len) {
+        error_report("Unexpected config length 0x%x. Expected 0x%zx",
+                     config_len, vdev->config_len);
+        return -1;
+    }
     qemu_get_buffer(f, vdev->config, vdev->config_len);
 
     num = qemu_get_be32(f);
-- 
1.7.1