1 From ea96c6a9c91da1923aa922a781fd7abbf9f51b6c Mon Sep 17 00:00:00 2001
2 From: "Michael S. Tsirkin" <mst@redhat.com>
3 Date: Thu, 3 Apr 2014 19:50:39 +0300
4 Subject: [PATCH] virtio-net: fix buffer overflow on invalid state load
6 CVE-2013-4148 QEMU 1.0 integer conversion in
7 virtio_net_load()@hw/net/virtio-net.c
9 Deals with loading a corrupted savevm image.
11 > n->mac_table.in_use = qemu_get_be32(f);
13 in_use is int so it can get negative when assigned 32bit unsigned value.
15 > /* MAC_TABLE_ENTRIES may be different from the saved image */
16 > if (n->mac_table.in_use <= MAC_TABLE_ENTRIES) {
18 passing this check ^^^
20 > qemu_get_buffer(f, n->mac_table.macs,
21 > n->mac_table.in_use * ETH_ALEN);
23 with good in_use value, "n->mac_table.in_use * ETH_ALEN" can get
24 positive and bigger than mac_table.macs. For example 0x81000000
25 satisfies this condition when ETH_ALEN is 6.
27 Fix it by making the value unsigned.
28 For consistency, change first_multi as well.
30 Note: all call sites were audited to confirm that
31 making them unsigned didn't cause any issues:
32 it turns out we actually never do math on them,
33 so it's easy to validate because both values are
34 always <= MAC_TABLE_ENTRIES.
36 Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
37 Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
38 Reviewed-by: Laszlo Ersek <lersek@redhat.com>
39 Signed-off-by: Juan Quintela <quintela@redhat.com>
40 (cherry picked from commit 71f7fe48e10a8437c9d42d859389f37157f59980)
42 include/hw/virtio/virtio-net.h | 4 ++--
43 1 file changed, 2 insertions(+), 2 deletions(-)
45 diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h
46 index df60f16..4b32440 100644
47 --- a/include/hw/virtio/virtio-net.h
48 +++ b/include/hw/virtio/virtio-net.h
49 @@ -176,8 +176,8 @@ typedef struct VirtIONet {
51 uint8_t vhost_started;
56 + uint32_t first_multi;
57 uint8_t multi_overflow;