From 7ee3c61dcd28bf6e290e06ad382f13511dc790e9 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Wed, 7 Apr 2021 21:43:39 +0200 Subject: netfilter: bridge: add pre_exit hooks for ebtable unregistration Just like ip/ip6/arptables, the hooks have to be removed, then synchronize_rcu() has to be called to make sure no more packets are being processed before the ruleset data is released. Place the hook unregistration in the pre_exit hook, then call the new ebtables pre_exit function from there. Years ago, when first netns support got added for netfilter+ebtables, this used an older (now removed) netfilter hook unregister API, that did a unconditional synchronize_rcu(). Now that all is done with call_rcu, ebtable_{filter,nat,broute} pernet exit handlers may free the ebtable ruleset while packets are still in flight. This can only happens on module removal, not during netns exit. The new function expects the table name, not the table struct. This is because upcoming patch set (targeting -next) will remove all net->xt.{nat,filter,broute}_table instances, this makes it necessary to avoid external references to those member variables. The existing APIs will be converted, so follow the upcoming scheme of passing name + hook type instead. Fixes: aee12a0a3727e ("ebtables: remove nf_hook_register usage") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/linux/netfilter_bridge/ebtables.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/netfilter_bridge/ebtables.h b/include/linux/netfilter_bridge/ebtables.h index 2f5c4e6ecd8a..3a956145a25c 100644 --- a/include/linux/netfilter_bridge/ebtables.h +++ b/include/linux/netfilter_bridge/ebtables.h @@ -110,8 +110,9 @@ extern int ebt_register_table(struct net *net, const struct ebt_table *table, const struct nf_hook_ops *ops, struct ebt_table **res); -extern void ebt_unregister_table(struct net *net, struct ebt_table *table, - const struct nf_hook_ops *); +extern void ebt_unregister_table(struct net *net, struct ebt_table *table); +void ebt_unregister_table_pre_exit(struct net *net, const char *tablename, + const struct nf_hook_ops *ops); extern unsigned int ebt_do_table(struct sk_buff *skb, const struct nf_hook_state *state, struct ebt_table *table); -- cgit v1.2.3 From d163a925ebbc6eb5b562b0f1d72c7e817aa75c40 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Wed, 7 Apr 2021 21:43:40 +0200 Subject: netfilter: arp_tables: add pre_exit hook for table unregister Same problem that also existed in iptables/ip(6)tables, when arptable_filter is removed there is no longer a wait period before the table/ruleset is free'd. Unregister the hook in pre_exit, then remove the table in the exit function. This used to work correctly because the old nf_hook_unregister API did unconditional synchronize_net. The per-net hook unregister function uses call_rcu instead. Fixes: b9e69e127397 ("netfilter: xtables: don't hook tables by default") Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- include/linux/netfilter_arp/arp_tables.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/netfilter_arp/arp_tables.h b/include/linux/netfilter_arp/arp_tables.h index 7d3537c40ec9..26a13294318c 100644 --- a/include/linux/netfilter_arp/arp_tables.h +++ b/include/linux/netfilter_arp/arp_tables.h @@ -52,8 +52,9 @@ extern void *arpt_alloc_initial_table(const struct xt_table *); int arpt_register_table(struct net *net, const struct xt_table *table, const struct arpt_replace *repl, const struct nf_hook_ops *ops, struct xt_table **res); -void arpt_unregister_table(struct net *net, struct xt_table *table, - const struct nf_hook_ops *ops); +void arpt_unregister_table(struct net *net, struct xt_table *table); +void arpt_unregister_table_pre_exit(struct net *net, struct xt_table *table, + const struct nf_hook_ops *ops); extern unsigned int arpt_do_table(struct sk_buff *skb, const struct nf_hook_state *state, struct xt_table *table); -- cgit v1.2.3