1 From 1a29e58f9f23846d0e105a3157629786fc624f65 Mon Sep 17 00:00:00 2001
2 From: "Michael S. Tsirkin" <mst@redhat.com>
3 Date: Mon, 28 Apr 2014 16:08:21 +0300
4 Subject: [PATCH] virtio-net: out-of-bounds buffer write on load
6 CVE-2013-4149 QEMU 1.3.0 out-of-bounds buffer write in
7 virtio_net_load()@hw/net/virtio-net.c
9 > } else if (n->mac_table.in_use) {
10 > uint8_t *buf = g_malloc0(n->mac_table.in_use);
12 We are allocating buffer of size n->mac_table.in_use
14 > qemu_get_buffer(f, buf, n->mac_table.in_use * ETH_ALEN);
16 and read to the n->mac_table.in_use size buffer n->mac_table.in_use *
17 ETH_ALEN bytes, corrupting memory.
19 If adversary controls state then memory written there is controlled
22 Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
23 Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
24 Signed-off-by: Juan Quintela <quintela@redhat.com>
25 (cherry picked from commit 98f93ddd84800f207889491e0b5d851386b459cf)
27 hw/net/virtio-net.c | 15 +++++++++++----
28 1 file changed, 11 insertions(+), 4 deletions(-)
30 diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
31 index 0a8cb40..940a7cf 100644
32 --- a/hw/net/virtio-net.c
33 +++ b/hw/net/virtio-net.c
34 @@ -1362,10 +1362,17 @@ static int virtio_net_load(QEMUFile *f, void *opaque, int version_id)
35 if (n->mac_table.in_use <= MAC_TABLE_ENTRIES) {
36 qemu_get_buffer(f, n->mac_table.macs,
37 n->mac_table.in_use * ETH_ALEN);
38 - } else if (n->mac_table.in_use) {
39 - uint8_t *buf = g_malloc0(n->mac_table.in_use);
40 - qemu_get_buffer(f, buf, n->mac_table.in_use * ETH_ALEN);
45 + /* Overflow detected - can happen if source has a larger MAC table.
46 + * We simply set overflow flag so there's no need to maintain the
47 + * table of addresses, discard them all.
48 + * Note: 64 bit math to avoid integer overflow.
50 + for (i = 0; i < (int64_t)n->mac_table.in_use * ETH_ALEN; ++i) {
53 n->mac_table.multi_overflow = n->mac_table.uni_overflow = 1;
54 n->mac_table.in_use = 0;