netfilter: nf_queue: move hookfn registration out of struct net

This was done to detect when the pernet->init() function was not called
yet, by checking if net->nf.queue_handler is NULL.

Once the nfnetlink_queue module is active, all struct net pointers
contain the same address.  So place this back in nf_queue.c.

Handle the 'netns error unwind' test by checking nfnl_queue_net for a
NULL pointer and add a comment for this.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 13 insertions, 2 deletions

diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index f774de0fc24f..4c3fbaaeb103 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -951,6 +951,16 @@ static void nfqnl_nf_hook_drop(struct net *net)
 	struct nfnl_queue_net *q = nfnl_queue_pernet(net);
 	int i;
 
+	/* This function is also called on net namespace error unwind,
+	 * when pernet_ops->init() failed and ->exit() functions of the
+	 * previous pernet_ops gets called.
+	 *
+	 * This may result in a call to nfqnl_nf_hook_drop() before
+	 * struct nfnl_queue_net was allocated.
+	 */
+	if (!q)
+		return;
+
 	for (i = 0; i < INSTANCE_BUCKETS; i++) {
 		struct nfqnl_instance *inst;
 		struct hlist_head *head = &q->instance_table[i];
@@ -1502,7 +1512,6 @@ static int __net_init nfnl_queue_net_init(struct net *net)
 			&nfqnl_seq_ops, sizeof(struct iter_state)))
 		return -ENOMEM;
 #endif
-	nf_register_queue_handler(net, &nfqh);
 	return 0;
 }
 
@@ -1511,7 +1520,6 @@ static void __net_exit nfnl_queue_net_exit(struct net *net)
 	struct nfnl_queue_net *q = nfnl_queue_pernet(net);
 	unsigned int i;
 
-	nf_unregister_queue_handler(net);
 #ifdef CONFIG_PROC_FS
 	remove_proc_entry("nfnetlink_queue", net->nf.proc_netfilter);
 #endif
@@ -1555,6 +1563,8 @@ static int __init nfnetlink_queue_init(void)
 		goto cleanup_netlink_subsys;
 	}
 
+	nf_register_queue_handler(&nfqh);
+
 	return status;
 
 cleanup_netlink_subsys:
@@ -1568,6 +1578,7 @@ out:
 
 static void __exit nfnetlink_queue_fini(void)
 {
+	nf_unregister_queue_handler();
 	unregister_netdevice_notifier(&nfqnl_dev_notifier);
 	nfnetlink_subsys_unregister(&nfqnl_subsys);
 	netlink_unregister_notifier(&nfqnl_rtnl_notifier);