netns: bond: allow unprivileged users to control bond device

reduce the permission check of bond device's ioctl.
allow the userns root to control the bond device.

Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -3612,6 +3612,7 @@ static int bond_do_ioctl(struct net_device *bond_dev, struct ifreq *ifr, int cmd
 	struct ifslave k_sinfo;
 	struct ifslave __user *u_sinfo = NULL;
 	struct mii_ioctl_data *mii = NULL;
+	struct net *net;
 	int res = 0;
 
 	pr_debug("bond_ioctl: master=%s, cmd=%d\n", bond_dev->name, cmd);
@@ -3678,10 +3679,12 @@ static int bond_do_ioctl(struct net_device *bond_dev, struct ifreq *ifr, int cmd
 		break;
 	}
 
-	if (!capable(CAP_NET_ADMIN))
+	net = dev_net(bond_dev);
+
+	if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
 		return -EPERM;
 
-	slave_dev = dev_get_by_name(dev_net(bond_dev), ifr->ifr_slave);
+	slave_dev = dev_get_by_name(net, ifr->ifr_slave);
 
 	pr_debug("slave_dev=%p:\n", slave_dev);