CVE-2013-4148 QEMU 1.0 integer conversion in
virtio_net_load()@hw/net/virtio-net.c
Deals with loading a corrupted savevm image.
> n->mac_table.in_use = qemu_get_be32(f);
in_use is int so it can get negative when assigned 32bit unsigned value.
> /* MAC_TABLE_ENTRIES may be different from the saved image */
> if (n->mac_table.in_use <= MAC_TABLE_ENTRIES) {
passing this check ^^^
> qemu_get_buffer(f, n->mac_table.macs,
> n->mac_table.in_use * ETH_ALEN);
with good in_use value, "n->mac_table.in_use * ETH_ALEN" can get
positive and bigger than mac_table.macs. For example 0x81000000
satisfies this condition when ETH_ALEN is 6.
A similar problem exists with is_multi.
Fix both by making the value unsigned.
Reviewed-by: Michael Roth <mdr...@linux.vnet.ibm.com>
Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
Edit: "for consistency, change first_multi as well".
Note: all call sites were audited to confirm that
making them unsigned didn't cause any issues:
it turns out we actually never do math on them,
so it's easy to validate because both values are
always <= MAC_TABLE_ENTRIES.
---
include/hw/virtio/virtio-net.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/hw/virtio/virtio-net.h b/include/hw/virtio/virtio-net.h
index df60f16..4b32440 100644
--- a/include/hw/virtio/virtio-net.h
+++ b/include/hw/virtio/virtio-net.h
@@ -176,8 +176,8 @@ typedef struct VirtIONet {
uint8_t nobcast;
uint8_t vhost_started;
struct {
- int in_use;
- int first_multi;
+ uint32_t in_use;
+ uint32_t first_multi;
uint8_t multi_overflow;
uint8_t uni_overflow;
uint8_t *macs;
--
MST
