net: Allow the userns root to control vlans.

Allow an unpriviled user who has created a user namespace, and then
created a network namespace to effectively use the new network
namespace, by reducing capable(CAP_NET_ADMIN) and
capable(CAP_NET_RAW) calls to be ns_capable(net->user_ns,
CAP_NET_ADMIN), or capable(net->user_ns, CAP_NET_RAW) calls.

Allow the vlan ioctls:
SET_VLAN_INGRESS_PRIORITY_CMD
SET_VLAN_EGRESS_PRIORITY_CMD
SET_VLAN_FLAG_CMD
SET_VLAN_NAME_TYPE_CMD
ADD_VLAN_CMD
DEL_VLAN_CMD

Signed-off-by: "Eric W. Biederman" <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/8021q/vlan.c

···
 	switch (args.cmd) {
 	case SET_VLAN_INGRESS_PRIORITY_CMD:
 		err = -EPERM;
-		if (!capable(CAP_NET_ADMIN))
+		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
 			break;
 		vlan_dev_set_ingress_priority(dev,
 					      args.u.skb_priority,
···
 
 	case SET_VLAN_EGRESS_PRIORITY_CMD:
 		err = -EPERM;
-		if (!capable(CAP_NET_ADMIN))
+		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
 			break;
 		err = vlan_dev_set_egress_priority(dev,
 						   args.u.skb_priority,
···
 
 	case SET_VLAN_FLAG_CMD:
 		err = -EPERM;
-		if (!capable(CAP_NET_ADMIN))
+		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
 			break;
 		err = vlan_dev_change_flags(dev,
 					    args.vlan_qos ? args.u.flag : 0,
···
 
 	case SET_VLAN_NAME_TYPE_CMD:
 		err = -EPERM;
-		if (!capable(CAP_NET_ADMIN))
+		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
 			break;
 		if ((args.u.name_type >= 0) &&
 		    (args.u.name_type < VLAN_NAME_TYPE_HIGHEST)) {
···
 
 	case ADD_VLAN_CMD:
 		err = -EPERM;
-		if (!capable(CAP_NET_ADMIN))
+		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
 			break;
 		err = register_vlan_device(dev, args.u.VID);
 		break;
 
 	case DEL_VLAN_CMD:
 		err = -EPERM;
-		if (!capable(CAP_NET_ADMIN))
+		if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
 			break;
 		unregister_vlan_dev(dev, NULL);
 		err = 0;