[PATCH 4.16 08/68] vhost: Fix vhost_copy_to_user()

[Greg Kroah-Hartman]

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Eric Auger <eric.auger@xxxxxxxxxx>


[ Upstream commit 7ced6c98c7ab7a1f6743931e28671b833af79b1e ]

vhost_copy_to_user is used to copy vring used elements to userspace.
We should use VHOST_ADDR_USED instead of VHOST_ADDR_DESC.

Fixes: f88949138058 ("vhost: introduce O(1) vq metadata cache")
Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/vhost/vhost.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -744,7 +744,7 @@ static int vhost_copy_to_user(struct vho
 		struct iov_iter t;
 		void __user *uaddr = vhost_vq_meta_fetch(vq,
 				     (u64)(uintptr_t)to, size,
-				     VHOST_ADDR_DESC);
+				     VHOST_ADDR_USED);
 
 		if (uaddr)
 			return __copy_to_user(uaddr, from, size);