virtio-scsi: fix buffer overrun on invalid state load
CVE-2013-4542
hw/scsi/scsi-bus.c invokes load_request.
virtio_scsi_load_request does:
qemu_get_buffer(f, (unsigned char *)&req->elem, sizeof(req->elem));
this probably can make elem invalid, for example,
make in_num or out_num huge, then:
virtio_scsi_parse_req(s, vs->cmd_vqs[n], req);
will do:
if (req->elem.out_num > 1) {
qemu_sgl_init_external(req, &req->elem.out_sg[1],
&req->elem.out_addr[1],
req->elem.out_num - 1);
} else {
qemu_sgl_init_external(req, &req->elem.in_sg[1],
&req->elem.in_addr[1],
req->elem.in_num - 1);
}
and this will access out of array bounds.
Note: this adds security checks within assert calls since
SCSIBusInfo's load_request cannot fail.
For now simply disable builds with NDEBUG - there seems
to be little value in supporting these.
Cc: Andreas Färber <afaerber@suse.de>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>