netlink: Make NETLINK_USERSOCK work again.

Once we started enforcing the a nl_table[] entry exist for
a protocol, NETLINK_USERSOCK stopped working.  Add a dummy
table entry so that it works again.

Reported-by: Thomas Voegtle <tv@lio96.de>
Tested-by: Thomas Voegtle <tv@lio96.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 22 insertions, 0 deletions

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 980fe4ad0016..cd96ed3ccee4 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2102,6 +2102,26 @@ static void __net_exit netlink_net_exit(struct net *net)
 #endif
 }
 
+static void __init netlink_add_usersock_entry(void)
+{
+        unsigned long *listeners;
+        int groups = 32;
+
+        listeners = kzalloc(NLGRPSZ(groups) + sizeof(struct listeners_rcu_head),
+                            GFP_KERNEL);
+        if (!listeners)
+                panic("netlink_add_usersock_entry: Cannot allocate listneres\n");
+
+        netlink_table_grab();
+
+        nl_table[NETLINK_USERSOCK].groups = groups;
+        nl_table[NETLINK_USERSOCK].listeners = listeners;
+        nl_table[NETLINK_USERSOCK].module = THIS_MODULE;
+        nl_table[NETLINK_USERSOCK].registered = 1;
+
+        netlink_table_ungrab();
+}
+
 static struct pernet_operations __net_initdata netlink_net_ops = {
         .init = netlink_net_init,
         .exit = netlink_net_exit,
@@ -2150,6 +2170,8 @@ static int __init netlink_proto_init(void)
                 hash->rehash_time = jiffies;
         }
 
+        netlink_add_usersock_entry();
+
         sock_register(&netlink_family_ops);
         register_pernet_subsys(&netlink_net_ops);
         /* The netlink device handler may be needed early. */