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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 2591ffd308
["netns: remove BUG_ONs from net_generic()"].

Signed-off-by: Francesco Ruggeri <fruggeri@arista.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Francesco Ruggeri 2015-05-17 14:30:31 -07:00 committed by Pablo Neira Ayuso
parent 13c3ed6a92
commit 3bfe049807
2 changed files with 19 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
net/netfilter/nfnetlink_log.c
View File

@ -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");

18
net/netfilter/nfnetlink_queue_core.c
View File

@ -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 */
}