net: rtnl: info leak in rtnl_fill_vfinfo()

The "vf_vlan_info" struct ends with a 2 byte struct hole so we have to
memset it to ensure that no stack information is revealed to user space.

Fixes: 79aab093a0b5 ('net: Update API for VF vlan protocol 802.1ad support')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/rtnetlink.c

@@ -1144,6 +1144,8 @@ static noinline_for_stack int rtnl_fill_vfinfo(struct sk_buff *skb,
 	if (dev->netdev_ops->ndo_get_vf_config(dev, vfs_num, &ivi))
 		return 0;
 
+	memset(&vf_vlan_info, 0, sizeof(vf_vlan_info));
+
 	vf_mac.vf =
 		vf_vlan.vf =
 		vf_vlan_info.vf =