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authorMichael S. Tsirkin <mst@redhat.com>2014-04-28 16:08:21 +0300
committerJuan Quintela <quintela@redhat.com>2014-05-05 22:15:03 +0200
commit98f93ddd84800f207889491e0b5d851386b459cf (patch)
tree085acc36e1693aca021848f1b2de9d2bbe0c5dda /hw/net
parent73d963c0a75cb99c6aaa3f6f25e427aa0b35a02e (diff)
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>
Diffstat (limited to 'hw/net')
-rw-r--r--hw/net/virtio-net.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 0a8cb40b92..940a7cfe54 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -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;
}