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[v4,06/30] virtio-net: out-of-bounds buffer write on invalid state load

Message ID 1396275242-10810-7-git-send-email-mst@redhat.com
State New
Headers show

Commit Message

Michael S. Tsirkin March 31, 2014, 2:16 p.m. UTC 
CVE-2013-4150 QEMU 1.5.0 out-of-bounds buffer write in
virtio_net_load()@hw/net/virtio-net.c

This code is in hw/net/virtio-net.c:

    if (n->max_queues > 1) {
        if (n->max_queues != qemu_get_be16(f)) {
            error_report("virtio-net: different max_queues ");
            return -1;
        }

        n->curr_queues = qemu_get_be16(f);
        for (i = 1; i < n->curr_queues; i++) {
            n->vqs[i].tx_waiting = qemu_get_be32(f);
        }
    }

Number of vqs is max_queues, so if we get invalid input here,
for example if max_queues = 2, curr_queues = 3, we get
write beyond end of the buffer, with data that comes from
wire.

This might be used to corrupt qemu memory in hard to predict ways.
Since we have lots of function pointers around, RCE might be possible.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---
 hw/net/virtio-net.c | 5 +++++
 1 file changed, 5 insertions(+)
diff mbox

Patch

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 8d037b1..c811fbd 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1413,6 +1413,11 @@  static int virtio_net_load(QEMUFile *f, void *opaque, int version_id)
         }
 
         n->curr_queues = qemu_get_be16(f);
+        if (n->curr_queues > n->max_queues) {
+            error_report("virtio-net: curr_queues %x > max_queues %x",
+                         n->curr_queues, n->max_queues);
+            return -1;
+        }
         for (i = 1; i < n->curr_queues; i++) {
             n->vqs[i].tx_waiting = qemu_get_be32(f);
         }