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netfilter: nf_queue: fix nf_queue_nf_hook_drop() 

This function reacquires the rtnl_lock() which is already held by
nf_unregister_hook().

This can be triggered via: modprobe nf_conntrack_ipv4 && rmmod nf_conntrack_ipv4

[  720.628746] INFO: task rmmod:3578 blocked for more than 120 seconds.
[  720.628749]       Not tainted 4.2.0-rc2+ #113
[  720.628752] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[  720.628754] rmmod           D ffff8800ca46fd58     0  3578   3571 0x00000080
[...]
[  720.628783] Call Trace:
[  720.628790]  [<ffffffff8152ea0b>] schedule+0x6b/0x90
[  720.628795]  [<ffffffff8152ecb3>] schedule_preempt_disabled+0x13/0x20
[  720.628799]  [<ffffffff8152ff55>] mutex_lock_nested+0x1f5/0x380
[  720.628803]  [<ffffffff81462622>] ? rtnl_lock+0x12/0x20
[  720.628807]  [<ffffffff81462622>] ? rtnl_lock+0x12/0x20
[  720.628812]  [<ffffffff81462622>] rtnl_lock+0x12/0x20
[  720.628817]  [<ffffffff8148ab25>] nf_queue_nf_hook_drop+0x15/0x160
[  720.628825]  [<ffffffff81488d48>] nf_unregister_net_hook+0x168/0x190
[  720.628831]  [<ffffffff81488e24>] nf_unregister_hook+0x64/0x80
[  720.628837]  [<ffffffff81488e60>] nf_unregister_hooks+0x20/0x30
[...]

Moreover, nf_unregister_net_hook() should only destroy the queue for this
netns, not for every netns.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Fixes: 085db2c045 ("netfilter: Per network namespace netfilter hooks.")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
This commit is contained in:
Pablo Neira Ayuso 2015-07-20 12:55:02 +02:00
parent e317fa505d
commit 2385eb0c5f
3 changed files with 5 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
net/netfilter/core.c
View File

@ -154,7 +154,7 @@ void nf_unregister_net_hook(struct net *net, const struct nf_hook_ops *reg)
static_key_slow_dec(&nf_hooks_needed[reg->pf][reg->hooknum]); static_key_slow_dec(&nf_hooks_needed[reg->pf][reg->hooknum]);
#endif #endif
synchronize_net(); synchronize_net();
nf_queue_nf_hook_drop(elem); nf_queue_nf_hook_drop(net, elem);
kfree(elem); kfree(elem);
} }
EXPORT_SYMBOL(nf_unregister_net_hook); EXPORT_SYMBOL(nf_unregister_net_hook);

2
net/netfilter/nf_internals.h
View File

@ -19,7 +19,7 @@ unsigned int nf_iterate(struct list_head *head, struct sk_buff *skb,
/* nf_queue.c */ /* nf_queue.c */
int nf_queue(struct sk_buff *skb, struct nf_hook_ops *elem, int nf_queue(struct sk_buff *skb, struct nf_hook_ops *elem,
struct nf_hook_state *state, unsigned int queuenum); struct nf_hook_state *state, unsigned int queuenum);
void nf_queue_nf_hook_drop(struct nf_hook_ops *ops); void nf_queue_nf_hook_drop(struct net *net, struct nf_hook_ops *ops);
int __init netfilter_queue_init(void); int __init netfilter_queue_init(void);
/* nf_log.c */ /* nf_log.c */

12
net/netfilter/nf_queue.c
View File

@ -105,21 +105,15 @@ bool nf_queue_entry_get_refs(struct nf_queue_entry *entry)
} }
EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs); EXPORT_SYMBOL_GPL(nf_queue_entry_get_refs);
void nf_queue_nf_hook_drop(struct nf_hook_ops *ops) void nf_queue_nf_hook_drop(struct net *net, struct nf_hook_ops *ops)
{ {
const struct nf_queue_handler *qh; const struct nf_queue_handler *qh;
struct net *net;
rtnl_lock();
rcu_read_lock(); rcu_read_lock();
qh = rcu_dereference(queue_handler); qh = rcu_dereference(queue_handler);
if (qh) { if (qh)
for_each_net(net) { qh->nf_hook_drop(net, ops);
qh->nf_hook_drop(net, ops);
}
}
rcu_read_unlock(); rcu_read_unlock();
rtnl_unlock();
} }
/* /*