From patchwork Mon Apr 12 22:30:57 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pablo Neira Ayuso X-Patchwork-Id: 419824 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2BFADC433ED for ; Mon, 12 Apr 2021 22:31:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E51A61358 for ; Mon, 12 Apr 2021 22:31:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343801AbhDLWbf (ORCPT ); Mon, 12 Apr 2021 18:31:35 -0400 Received: from mail.netfilter.org ([217.70.188.207]:50490 "EHLO mail.netfilter.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343753AbhDLWb2 (ORCPT ); Mon, 12 Apr 2021 18:31:28 -0400 Received: from localhost.localdomain (unknown [90.77.255.23]) by mail.netfilter.org (Postfix) with ESMTPSA id BC9D663E3D; Tue, 13 Apr 2021 00:30:43 +0200 (CEST) From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Cc: davem@davemloft.net, netdev@vger.kernel.org, kuba@kernel.org Subject: [PATCH net 5/7] netfilter: arp_tables: add pre_exit hook for table unregister Date: Tue, 13 Apr 2021 00:30:57 +0200 Message-Id: <20210412223059.20841-6-pablo@netfilter.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210412223059.20841-1-pablo@netfilter.org> References: <20210412223059.20841-1-pablo@netfilter.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Florian Westphal 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 +++-- 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)