From patchwork Wed Apr 7 19:43:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 1463499 X-Patchwork-Delegate: pablo@netfilter.org Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netfilter-devel-owner@vger.kernel.org; receiver=) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4FFvw86X9Qz9sWC for ; Thu, 8 Apr 2021 05:43:52 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355686AbhDGToB (ORCPT ); Wed, 7 Apr 2021 15:44:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60896 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355674AbhDGToB (ORCPT ); Wed, 7 Apr 2021 15:44:01 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:12e:520::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 95333C06175F for ; Wed, 7 Apr 2021 12:43:51 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1lUE5e-00028T-7V; Wed, 07 Apr 2021 21:43:50 +0200 From: Florian Westphal To: Cc: Florian Westphal Subject: [PATCH nf 1/2] netfilter: bridge: add pre_exit hooks for ebtable unregistration Date: Wed, 7 Apr 2021 21:43:39 +0200 Message-Id: <20210407194340.21594-2-fw@strlen.de> X-Mailer: git-send-email 2.26.3 In-Reply-To: <20210407194340.21594-1-fw@strlen.de> References: <20210407194340.21594-1-fw@strlen.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org 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 --- include/linux/netfilter_bridge/ebtables.h | 5 ++-- net/bridge/netfilter/ebtable_broute.c | 8 +++++- net/bridge/netfilter/ebtable_filter.c | 8 +++++- net/bridge/netfilter/ebtable_nat.c | 8 +++++- net/bridge/netfilter/ebtables.c | 30 ++++++++++++++++++++--- 5 files changed, 51 insertions(+), 8 deletions(-) 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); diff --git a/net/bridge/netfilter/ebtable_broute.c b/net/bridge/netfilter/ebtable_broute.c index 66e7af165494..32bc2821027f 100644 --- a/net/bridge/netfilter/ebtable_broute.c +++ b/net/bridge/netfilter/ebtable_broute.c @@ -105,14 +105,20 @@ static int __net_init broute_net_init(struct net *net) &net->xt.broute_table); } +static void __net_exit broute_net_pre_exit(struct net *net) +{ + ebt_unregister_table_pre_exit(net, "broute", &ebt_ops_broute); +} + static void __net_exit broute_net_exit(struct net *net) { - ebt_unregister_table(net, net->xt.broute_table, &ebt_ops_broute); + ebt_unregister_table(net, net->xt.broute_table); } static struct pernet_operations broute_net_ops = { .init = broute_net_init, .exit = broute_net_exit, + .pre_exit = broute_net_pre_exit, }; static int __init ebtable_broute_init(void) diff --git a/net/bridge/netfilter/ebtable_filter.c b/net/bridge/netfilter/ebtable_filter.c index 78cb9b21022d..bcf982e12f16 100644 --- a/net/bridge/netfilter/ebtable_filter.c +++ b/net/bridge/netfilter/ebtable_filter.c @@ -99,14 +99,20 @@ static int __net_init frame_filter_net_init(struct net *net) &net->xt.frame_filter); } +static void __net_exit frame_filter_net_pre_exit(struct net *net) +{ + ebt_unregister_table_pre_exit(net, "filter", ebt_ops_filter); +} + static void __net_exit frame_filter_net_exit(struct net *net) { - ebt_unregister_table(net, net->xt.frame_filter, ebt_ops_filter); + ebt_unregister_table(net, net->xt.frame_filter); } static struct pernet_operations frame_filter_net_ops = { .init = frame_filter_net_init, .exit = frame_filter_net_exit, + .pre_exit = frame_filter_net_pre_exit, }; static int __init ebtable_filter_init(void) diff --git a/net/bridge/netfilter/ebtable_nat.c b/net/bridge/netfilter/ebtable_nat.c index 0888936ef853..0d092773f816 100644 --- a/net/bridge/netfilter/ebtable_nat.c +++ b/net/bridge/netfilter/ebtable_nat.c @@ -99,14 +99,20 @@ static int __net_init frame_nat_net_init(struct net *net) &net->xt.frame_nat); } +static void __net_exit frame_nat_net_pre_exit(struct net *net) +{ + ebt_unregister_table_pre_exit(net, "nat", ebt_ops_nat); +} + static void __net_exit frame_nat_net_exit(struct net *net) { - ebt_unregister_table(net, net->xt.frame_nat, ebt_ops_nat); + ebt_unregister_table(net, net->xt.frame_nat); } static struct pernet_operations frame_nat_net_ops = { .init = frame_nat_net_init, .exit = frame_nat_net_exit, + .pre_exit = frame_nat_net_pre_exit, }; static int __init ebtable_nat_init(void) diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c index ebe33b60efd6..d481ff24a150 100644 --- a/net/bridge/netfilter/ebtables.c +++ b/net/bridge/netfilter/ebtables.c @@ -1232,10 +1232,34 @@ int ebt_register_table(struct net *net, const struct ebt_table *input_table, return ret; } -void ebt_unregister_table(struct net *net, struct ebt_table *table, - const struct nf_hook_ops *ops) +static struct ebt_table *__ebt_find_table(struct net *net, const char *name) +{ + struct ebt_table *t; + + mutex_lock(&ebt_mutex); + + list_for_each_entry(t, &net->xt.tables[NFPROTO_BRIDGE], list) { + if (strcmp(t->name, name) == 0) { + mutex_unlock(&ebt_mutex); + return t; + } + } + + mutex_unlock(&ebt_mutex); + return NULL; +} + +void ebt_unregister_table_pre_exit(struct net *net, const char *name, const struct nf_hook_ops *ops) +{ + struct ebt_table *table = __ebt_find_table(net, name); + + if (table) + nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks)); +} +EXPORT_SYMBOL(ebt_unregister_table_pre_exit); + +void ebt_unregister_table(struct net *net, struct ebt_table *table) { - nf_unregister_net_hooks(net, ops, hweight32(table->valid_hooks)); __ebt_unregister_table(net, table); } From patchwork Wed Apr 7 19:43:40 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 1463500 X-Patchwork-Delegate: pablo@netfilter.org Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netfilter-devel-owner@vger.kernel.org; receiver=) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4FFvwD5BBbz9sWC for ; Thu, 8 Apr 2021 05:43:56 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355687AbhDGToG (ORCPT ); Wed, 7 Apr 2021 15:44:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60914 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355674AbhDGToF (ORCPT ); Wed, 7 Apr 2021 15:44:05 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:12e:520::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B9B43C06175F for ; Wed, 7 Apr 2021 12:43:55 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1lUE5i-00028e-Cx; Wed, 07 Apr 2021 21:43:54 +0200 From: Florian Westphal To: Cc: Florian Westphal Subject: [PATCH nf 2/2] netfilter: arp_tables: netfilter: bridge: add pre_exit hook for table unregister Date: Wed, 7 Apr 2021 21:43:40 +0200 Message-Id: <20210407194340.21594-3-fw@strlen.de> X-Mailer: git-send-email 2.26.3 In-Reply-To: <20210407194340.21594-1-fw@strlen.de> References: <20210407194340.21594-1-fw@strlen.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org 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 --- include/linux/netfilter_arp/arp_tables.h | 5 +++-- net/ipv4/netfilter/arp_tables.c | 9 +++++++-- net/ipv4/netfilter/arptable_filter.c | 10 +++++++++- 3 files changed, 19 insertions(+), 5 deletions(-) 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); diff --git a/net/ipv4/netfilter/arp_tables.c b/net/ipv4/netfilter/arp_tables.c index d1e04d2b5170..6c26533480dd 100644 --- a/net/ipv4/netfilter/arp_tables.c +++ b/net/ipv4/netfilter/arp_tables.c @@ -1539,10 +1539,15 @@ int arpt_register_table(struct net *net, return ret; } -void arpt_unregister_table(struct net *net, struct xt_table *table, - const struct nf_hook_ops *ops) +void arpt_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)); +} +EXPORT_SYMBOL(arpt_unregister_table_pre_exit); + +void arpt_unregister_table(struct net *net, struct xt_table *table) +{ __arpt_unregister_table(net, table); } diff --git a/net/ipv4/netfilter/arptable_filter.c b/net/ipv4/netfilter/arptable_filter.c index c216b9ad3bb2..6c300ba5634e 100644 --- a/net/ipv4/netfilter/arptable_filter.c +++ b/net/ipv4/netfilter/arptable_filter.c @@ -56,16 +56,24 @@ static int __net_init arptable_filter_table_init(struct net *net) return err; } +static void __net_exit arptable_filter_net_pre_exit(struct net *net) +{ + if (net->ipv4.arptable_filter) + arpt_unregister_table_pre_exit(net, net->ipv4.arptable_filter, + arpfilter_ops); +} + static void __net_exit arptable_filter_net_exit(struct net *net) { if (!net->ipv4.arptable_filter) return; - arpt_unregister_table(net, net->ipv4.arptable_filter, arpfilter_ops); + arpt_unregister_table(net, net->ipv4.arptable_filter); net->ipv4.arptable_filter = NULL; } static struct pernet_operations arptable_filter_net_ops = { .exit = arptable_filter_net_exit, + .pre_exit = arptable_filter_net_pre_exit, }; static int __init arptable_filter_init(void)