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: 1b48dc03e575 ("vhost: vdpa: report iova range")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210728130756.97-1-xieyongji@bytedance.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 210ab35..9479f7f 100644 (file)
--- a/drivers/vhost/vdpa.c
+++ b/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;