From 651a486593475f02ab0aa531426ef5da135d3b7a Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Thu, 3 Apr 2014 19:50:56 +0300 Subject: [PATCH] virtio-net: out-of-bounds buffer write on invalid state load 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 Acked-by: Jason Wang Reviewed-by: Michael Roth Signed-off-by: Juan Quintela --- hw/net/virtio-net.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index 04dc62d4e..7cef41f38 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c @@ -1386,6 +1386,11 @@ 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); } -- 2.39.5