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virtio-net: out-of-bounds buffer write on load 

CVE-2013-4149 QEMU 1.3.0 out-of-bounds buffer write in
virtio_net_load()@hw/net/virtio-net.c

>         } else if (n->mac_table.in_use) {
>             uint8_t *buf = g_malloc0(n->mac_table.in_use);

We are allocating buffer of size n->mac_table.in_use

>             qemu_get_buffer(f, buf, n->mac_table.in_use * ETH_ALEN);

and read to the n->mac_table.in_use size buffer n->mac_table.in_use *
ETH_ALEN bytes, corrupting memory.

If adversary controls state then memory written there is controlled
by adversary.

Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
This commit is contained in:
Michael S. Tsirkin 2014-04-28 16:08:21 +03:00 committed by Juan Quintela
parent 73d963c0a7
commit 98f93ddd84
1 changed files with 11 additions and 4 deletions
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15
hw/net/virtio-net.c
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@ -1362,10 +1362,17 @@ static int virtio_net_load(QEMUFile *f, void *opaque, int version_id)
if (n->mac_table.in_use <= MAC_TABLE_ENTRIES) {
qemu_get_buffer(f, n->mac_table.macs,
n->mac_table.in_use * ETH_ALEN);
} else if (n->mac_table.in_use) {
uint8_t *buf = g_malloc0(n->mac_table.in_use);
qemu_get_buffer(f, buf, n->mac_table.in_use * ETH_ALEN);
g_free(buf);
} else {
int64_t i;
/* Overflow detected - can happen if source has a larger MAC table.
* We simply set overflow flag so there's no need to maintain the
* table of addresses, discard them all.
* Note: 64 bit math to avoid integer overflow.
*/
for (i = 0; i < (int64_t)n->mac_table.in_use * ETH_ALEN; ++i) {
qemu_get_byte(f);
}
n->mac_table.multi_overflow = n->mac_table.uni_overflow = 1;
n->mac_table.in_use = 0;
}