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Commit 3bfe0498 authored by Francesco Ruggeri's avatar Francesco Ruggeri Committed by Pablo Neira Ayuso
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netfilter: nfnetlink_{log,queue}: Register pernet in first place 



nfnetlink_{log,queue}_init() register the netlink callback nf*_rcv_nl_event
before registering the pernet_subsys, but the callback relies on data
structures allocated by pernet init functions.

When nfnetlink_{log,queue} is loaded, if a netlink message is received after
the netlink callback is registered but before the pernet_subsys is registered,
the kernel will panic in the sequence

nfulnl_rcv_nl_event
  nfnl_log_pernet
    net_generic
      BUG_ON(id == 0)  where id is nfnl_log_net_id.

The panic can be easily reproduced in 4.0.3 by:

while true ;do modprobe nfnetlink_log ; rmmod nfnetlink_log ; done &
while true ;do ip netns add dummy ; ip netns del dummy ; done &

This patch moves register_pernet_subsys to earlier in nfnetlink_log_init.

Notice that the BUG_ON hit in 4.0.3 was recently removed in 2591ffd3
["netns: remove BUG_ONs from net_generic()"].

Signed-off-by: default avatarFrancesco Ruggeri <fruggeri@arista.com>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent 13c3ed6a

net/netfilter/nfnetlink_log.c

+10 −9
Original line number Diff line number Diff line
@@ -1073,7 +1073,13 @@ static struct pernet_operations nfnl_log_net_ops = { 


static int __init nfnetlink_log_init(void)

{

	int status = -ENOMEM;

	int status;



	status = register_pernet_subsys(&nfnl_log_net_ops);

	if (status < 0) {

		pr_err("failed to register pernet ops\n");

		goto out;

	}



	netlink_register_notifier(&nfulnl_rtnl_notifier);

	status = nfnetlink_subsys_register(&nfulnl_subsys);
@@ -1088,28 +1094,23 @@ static int __init nfnetlink_log_init(void) 
		goto cleanup_subsys;

	}



	status = register_pernet_subsys(&nfnl_log_net_ops);

	if (status < 0) {

		pr_err("failed to register pernet ops\n");

		goto cleanup_logger;

	}

	return status;



cleanup_logger:

	nf_log_unregister(&nfulnl_logger);

cleanup_subsys:

	nfnetlink_subsys_unregister(&nfulnl_subsys);

cleanup_netlink_notifier:

	netlink_unregister_notifier(&nfulnl_rtnl_notifier);

	unregister_pernet_subsys(&nfnl_log_net_ops);

out:

	return status;

}



static void __exit nfnetlink_log_fini(void)

{

	unregister_pernet_subsys(&nfnl_log_net_ops);

	nf_log_unregister(&nfulnl_logger);

	nfnetlink_subsys_unregister(&nfulnl_subsys);

	netlink_unregister_notifier(&nfulnl_rtnl_notifier);

	unregister_pernet_subsys(&nfnl_log_net_ops);

}



MODULE_DESCRIPTION("netfilter userspace logging");

net/netfilter/nfnetlink_queue_core.c

+9 −9
Original line number Diff line number Diff line
@@ -1317,7 +1317,13 @@ static struct pernet_operations nfnl_queue_net_ops = { 


static int __init nfnetlink_queue_init(void)

{

	int status = -ENOMEM;

	int status;



	status = register_pernet_subsys(&nfnl_queue_net_ops);

	if (status < 0) {

		pr_err("nf_queue: failed to register pernet ops\n");

		goto out;

	}



	netlink_register_notifier(&nfqnl_rtnl_notifier);

	status = nfnetlink_subsys_register(&nfqnl_subsys);
@@ -1326,19 +1332,13 @@ static int __init nfnetlink_queue_init(void) 
		goto cleanup_netlink_notifier;

	}



	status = register_pernet_subsys(&nfnl_queue_net_ops);

	if (status < 0) {

		pr_err("nf_queue: failed to register pernet ops\n");

		goto cleanup_subsys;

	}

	register_netdevice_notifier(&nfqnl_dev_notifier);

	nf_register_queue_handler(&nfqh);

	return status;



cleanup_subsys:

	nfnetlink_subsys_unregister(&nfqnl_subsys);

cleanup_netlink_notifier:

	netlink_unregister_notifier(&nfqnl_rtnl_notifier);

out:

	return status;

}
@@ -1346,9 +1346,9 @@ static void __exit nfnetlink_queue_fini(void) 
{

	nf_unregister_queue_handler();

	unregister_netdevice_notifier(&nfqnl_dev_notifier);

	unregister_pernet_subsys(&nfnl_queue_net_ops);

	nfnetlink_subsys_unregister(&nfqnl_subsys);

	netlink_unregister_notifier(&nfqnl_rtnl_notifier);

	unregister_pernet_subsys(&nfnl_queue_net_ops);



	rcu_barrier(); /* Wait for completion of call_rcu()'s */

}