From: David Wilder <dwilder@us.ibm.com>
Date: Mon, 22 Jun 2020 10:10:11 -0700
Subject: netfilter: iptables: Split ipt_unregister_table() into pre_exit and exit helpers.
Patch-mainline: v5.8-rc3
Git-commit: 1cbf90985f7448f1b0dd630e17ee1070f7d58665
References: bsc#1171857
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 <dwilder@us.ibm.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Michal Kubecek <mkubecek@suse.cz>
---
include/linux/netfilter_ipv4/ip_tables.h | 6 ++++++
net/ipv4/netfilter/ip_tables.c | 15 ++++++++++++++-
2 files changed, 20 insertions(+), 1 deletion(-)
--- a/include/linux/netfilter_ipv4/ip_tables.h
+++ b/include/linux/netfilter_ipv4/ip_tables.h
@@ -28,6 +28,12 @@ extern void ipt_init(void) __init;
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);
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -1797,11 +1797,22 @@ int ipt_register_table(struct net *net, const struct xt_table *table,
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);