From 1cbf90985f7448f1b0dd630e17ee1070f7d58665 Mon Sep 17 00:00:00 2001 From: David Wilder Date: Mon, 22 Jun 2020 10:10:11 -0700 Subject: netfilter: iptables: Split ipt_unregister_table() into pre_exit and exit helpers. The pre_exit will un-register the underlying hook and .exit will do the table freeing. The netns core does an unconditional synchronize_rcu after the pre_exit hooks insuring no packets are in flight that have picked up the pointer before completing the un-register. Fixes: b9e69e127397 ("netfilter: xtables: don't hook tables by default") Signed-off-by: David Wilder Signed-off-by: Pablo Neira Ayuso --- include/linux/netfilter_ipv4/ip_tables.h | 6 ++++++ net/ipv4/netfilter/ip_tables.c | 15 ++++++++++++++- 2 files changed, 20 insertions(+), 1 deletion(-) diff --git a/include/linux/netfilter_ipv4/ip_tables.h b/include/linux/netfilter_ipv4/ip_tables.h index b394bd4f68a3..c4676d6feeff 100644 --- a/include/linux/netfilter_ipv4/ip_tables.h +++ b/include/linux/netfilter_ipv4/ip_tables.h @@ -25,6 +25,12 @@ int ipt_register_table(struct net *net, const struct xt_table *table, const struct ipt_replace *repl, const struct nf_hook_ops *ops, struct xt_table **res); + +void ipt_unregister_table_pre_exit(struct net *net, struct xt_table *table, + const struct nf_hook_ops *ops); + +void ipt_unregister_table_exit(struct net *net, struct xt_table *table); + void ipt_unregister_table(struct net *net, struct xt_table *table, const struct nf_hook_ops *ops); diff --git a/net/ipv4/netfilter/ip_tables.c b/net/ipv4/netfilter/ip_tables.c index c2670eaa74e6..5bf9fa06aee0 100644 --- a/net/ipv4/netfilter/ip_tables.c +++ b/net/ipv4/netfilter/ip_tables.c @@ -1797,11 +1797,22 @@ out_free: return ret; } +void ipt_unregister_table_pre_exit(struct net *net, struct xt_table *table, + const struct nf_hook_ops *ops) +{ + nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks)); +} + +void ipt_unregister_table_exit(struct net *net, struct xt_table *table) +{ + __ipt_unregister_table(net, table); +} + void ipt_unregister_table(struct net *net, struct xt_table *table, const struct nf_hook_ops *ops) { if (ops) - nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks)); + ipt_unregister_table_pre_exit(net, table, ops); __ipt_unregister_table(net, table); } @@ -1958,6 +1969,8 @@ static void __exit ip_tables_fini(void) EXPORT_SYMBOL(ipt_register_table); EXPORT_SYMBOL(ipt_unregister_table); +EXPORT_SYMBOL(ipt_unregister_table_pre_exit); +EXPORT_SYMBOL(ipt_unregister_table_exit); EXPORT_SYMBOL(ipt_do_table); module_init(ip_tables_init); module_exit(ip_tables_fini); -- cgit v1.2.3-59-g8ed1b