kobj: Send hotplug events in the proper namespace.

Utilize netlink_broacast_filtered to allow sending hotplug events
in the proper namespace.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

lib/kobject_uevent.c

@@ -83,6 +83,22 @@ int kobject_action_type(const char *buf, size_t count,
 	return ret;
 }
 
+static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data)
+{
+	struct kobject *kobj = data;
+	const struct kobj_ns_type_operations *ops;
+
+	ops = kobj_ns_ops(kobj);
+	if (ops) {
+		const void *sock_ns, *ns;
+		ns = kobj->ktype->namespace(kobj);
+		sock_ns = ops->netlink_ns(dsk);
+		return sock_ns != ns;
+	}
+
+	return 0;
+}
+
 /**
  * kobject_uevent_env - send an uevent with environmental data
  *
@@ -244,8 +260,10 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 			}
 
 			NETLINK_CB(skb).dst_group = 1;
-			retval = netlink_broadcast(uevent_sock, skb, 0, 1,
-						   GFP_KERNEL);
+			retval = netlink_broadcast_filtered(uevent_sock, skb,
+							    0, 1, GFP_KERNEL,
+							    kobj_bcast_filter,
+							    kobj);
 			/* ENOBUFS should be handled in userspace */
 			if (retval == -ENOBUFS)
 				retval = 0;