From 8702997074363c294a1f83928cd0c33ca57bf813 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Thu, 5 Aug 2021 12:02:43 +0200 Subject: [PATCH] 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 Signed-off-by: Pablo Neira Ayuso --- include/net/netfilter/nf_queue.h | 4 ++-- include/net/netns/netfilter.h | 1 - net/netfilter/nf_queue.c | 19 +++++++++---------- net/netfilter/nfnetlink_queue.c | 15 +++++++++++++-- 4 files changed, 24 insertions(+), 15 deletions(-) diff --git a/include/net/netfilter/nf_queue.h b/include/net/netfilter/nf_queue.h index e770bba00066..9eed51e920e8 100644 --- a/include/net/netfilter/nf_queue.h +++ b/include/net/netfilter/nf_queue.h @@ -33,8 +33,8 @@ struct nf_queue_handler { void (*nf_hook_drop)(struct net *net); }; -void nf_register_queue_handler(struct net *net, const struct nf_queue_handler *qh); -void nf_unregister_queue_handler(struct net *net); +void nf_register_queue_handler(const struct nf_queue_handler *qh); +void nf_unregister_queue_handler(void); void nf_reinject(struct nf_queue_entry *entry, unsigned int verdict); void nf_queue_entry_get_refs(struct nf_queue_entry *entry); diff --git a/include/net/netns/netfilter.h b/include/net/netns/netfilter.h index 15e2b13fb0c0..986a2a9cfdfa 100644 --- a/include/net/netns/netfilter.h +++ b/include/net/netns/netfilter.h @@ -12,7 +12,6 @@ struct netns_nf { #if defined CONFIG_PROC_FS struct proc_dir_entry *proc_netfilter; #endif - const struct nf_queue_handler __rcu *queue_handler; const struct nf_logger __rcu *nf_loggers[NFPROTO_NUMPROTO]; #ifdef CONFIG_SYSCTL struct ctl_table_header *nf_log_dir_header; diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c index bbd1209694b8..4903da82dc04 100644 --- a/net/netfilter/nf_queue.c +++ b/net/netfilter/nf_queue.c @@ -21,6 +21,8 @@ #include "nf_internals.h" +static const struct nf_queue_handler __rcu *nf_queue_handler; + /* * Hook for nfnetlink_queue to register its queue handler. * We do this so that most of the NFQUEUE code can be modular. @@ -29,20 +31,18 @@ * receives, no matter what. */ -/* return EBUSY when somebody else is registered, return EEXIST if the - * same handler is registered, return 0 in case of success. */ -void nf_register_queue_handler(struct net *net, const struct nf_queue_handler *qh) +void nf_register_queue_handler(const struct nf_queue_handler *qh) { /* should never happen, we only have one queueing backend in kernel */ - WARN_ON(rcu_access_pointer(net->nf.queue_handler)); - rcu_assign_pointer(net->nf.queue_handler, qh); + WARN_ON(rcu_access_pointer(nf_queue_handler)); + rcu_assign_pointer(nf_queue_handler, qh); } EXPORT_SYMBOL(nf_register_queue_handler); /* The caller must flush their queue before this */ -void nf_unregister_queue_handler(struct net *net) +void nf_unregister_queue_handler(void) { - RCU_INIT_POINTER(net->nf.queue_handler, NULL); + RCU_INIT_POINTER(nf_queue_handler, NULL); } EXPORT_SYMBOL(nf_unregister_queue_handler); @@ -116,7 +116,7 @@ void nf_queue_nf_hook_drop(struct net *net) const struct nf_queue_handler *qh; rcu_read_lock(); - qh = rcu_dereference(net->nf.queue_handler); + qh = rcu_dereference(nf_queue_handler); if (qh) qh->nf_hook_drop(net); rcu_read_unlock(); @@ -157,12 +157,11 @@ static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state, { struct nf_queue_entry *entry = NULL; const struct nf_queue_handler *qh; - struct net *net = state->net; unsigned int route_key_size; int status; /* QUEUE == DROP if no one is waiting, to be safe. */ - qh = rcu_dereference(net->nf.queue_handler); + qh = rcu_dereference(nf_queue_handler); if (!qh) return -ESRCH; 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);