vhost-vdpa: Fix integer overflow in vhost_vdpa_process_iotlb_update()

The "msg->iova + msg->size" addition can have an integer overflow
if the iotlb message is from a malicious user space application.
So let's fix it.

Fixes: 1b48dc0 ("vhost: vdpa: report iova range")
Reported-by: Dan Carpenter <[email protected]>
Signed-off-by: Xie Yongji <[email protected]>
Acked-by: Jason Wang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Michael S. Tsirkin <[email protected]>

Author: YongjiXie

drivers/vhost/vdpa.c

@@ -614,7 +614,8 @@ static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
 	long pinned;
 	int ret = 0;
 
-	if (msg->iova < v->range.first ||
+	if (msg->iova < v->range.first || !msg->size ||
+	    msg->iova > U64_MAX - msg->size + 1 ||
 	    msg->iova + msg->size - 1 > v->range.last)
 		return -EINVAL;