From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 06541C433EF for ; Mon, 30 May 2022 16:24:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241881AbiE3QYP (ORCPT ); Mon, 30 May 2022 12:24:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39320 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241826AbiE3QYN (ORCPT ); Mon, 30 May 2022 12:24:13 -0400 Received: from mail.netfilter.org (mail.netfilter.org [217.70.188.207]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 13176692B2 for ; Mon, 30 May 2022 09:24:12 -0700 (PDT) From: Pablo Neira Ayuso To: netfilter-devel@vger.kernel.org Subject: [PATCH nf,v2 2/2] netfilter: nf_tables: double hook unregistration in netns path Date: Mon, 30 May 2022 18:24:06 +0200 Message-Id: <20220530162406.3935-2-pablo@netfilter.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220530162406.3935-1-pablo@netfilter.org> References: <20220530162406.3935-1-pablo@netfilter.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org __nft_release_hooks() is called from pre_netns exit path which unregisters the hooks, then the NETDEV_UNREGISTER event is triggered which unregisters the hooks again. [ 565.221461] WARNING: CPU: 18 PID: 193 at net/netfilter/core.c:495 __nf_unregister_net_hook+0x247/0x270 [...] [ 565.246890] CPU: 18 PID: 193 Comm: kworker/u64:1 Tainted: G E 5.18.0-rc7+ #27 [ 565.253682] Workqueue: netns cleanup_net [ 565.257059] RIP: 0010:__nf_unregister_net_hook+0x247/0x270 [...] [ 565.297120] Call Trace: [ 565.300900] [ 565.304683] nf_tables_flowtable_event+0x16a/0x220 [nf_tables] [ 565.308518] raw_notifier_call_chain+0x63/0x80 [ 565.312386] unregister_netdevice_many+0x54f/0xb50 Unregister and destroy netdev hook from netns pre_exit via kfree_rcu so the NETDEV_UNREGISTER path see unregistered hooks. Fixes: 767d1216bff8 ("netfilter: nftables: fix possible UAF over chains from packet path in netns") Signed-off-by: Pablo Neira Ayuso --- v2: no changes. net/netfilter/nf_tables_api.c | 54 ++++++++++++++++++++++++++--------- 1 file changed, 41 insertions(+), 13 deletions(-) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 2c6c956c7bbc..7c9eb8e42ea6 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -222,12 +222,18 @@ static int nft_netdev_register_hooks(struct net *net, } static void nft_netdev_unregister_hooks(struct net *net, - struct list_head *hook_list) + struct list_head *hook_list, + bool release_netdev) { - struct nft_hook *hook; + struct nft_hook *hook, *next; - list_for_each_entry(hook, hook_list, list) + list_for_each_entry_safe(hook, next, hook_list, list) { nf_unregister_net_hook(net, &hook->ops); + if (release_netdev) { + list_del(&hook->list); + kfree_rcu(hook, rcu); + } + } } static int nf_tables_register_hook(struct net *net, @@ -253,9 +259,10 @@ static int nf_tables_register_hook(struct net *net, return nf_register_net_hook(net, &basechain->ops); } -static void nf_tables_unregister_hook(struct net *net, - const struct nft_table *table, - struct nft_chain *chain) +static void __nf_tables_unregister_hook(struct net *net, + const struct nft_table *table, + struct nft_chain *chain, + bool release_netdev) { struct nft_base_chain *basechain; const struct nf_hook_ops *ops; @@ -270,11 +277,19 @@ static void nf_tables_unregister_hook(struct net *net, return basechain->type->ops_unregister(net, ops); if (nft_base_chain_netdev(table->family, basechain->ops.hooknum)) - nft_netdev_unregister_hooks(net, &basechain->hook_list); + nft_netdev_unregister_hooks(net, &basechain->hook_list, + release_netdev); else nf_unregister_net_hook(net, &basechain->ops); } +static void nf_tables_unregister_hook(struct net *net, + const struct nft_table *table, + struct nft_chain *chain) +{ + return __nf_tables_unregister_hook(net, table, chain, false); +} + static void nft_trans_commit_list_add_tail(struct net *net, struct nft_trans *trans) { struct nftables_pernet *nft_net = nft_pernet(net); @@ -7291,13 +7306,25 @@ static void nft_unregister_flowtable_hook(struct net *net, FLOW_BLOCK_UNBIND); } -static void nft_unregister_flowtable_net_hooks(struct net *net, - struct list_head *hook_list) +static void __nft_unregister_flowtable_net_hooks(struct net *net, + struct list_head *hook_list, + bool release_netdev) { - struct nft_hook *hook; + struct nft_hook *hook, *next; - list_for_each_entry(hook, hook_list, list) + list_for_each_entry_safe(hook, next, hook_list, list) { nf_unregister_net_hook(net, &hook->ops); + if (release_netdev) { + list_del(&hook->list); + kfree_rcu(hook); + } + } +} + +static void nft_unregister_flowtable_net_hooks(struct net *net, + struct list_head *hook_list) +{ + __nft_unregister_flowtable_net_hooks(net, hook_list, false); } static int nft_register_flowtable_net_hooks(struct net *net, @@ -9741,9 +9768,10 @@ static void __nft_release_hook(struct net *net, struct nft_table *table) struct nft_chain *chain; list_for_each_entry(chain, &table->chains, list) - nf_tables_unregister_hook(net, table, chain); + __nf_tables_unregister_hook(net, table, chain, true); list_for_each_entry(flowtable, &table->flowtables, list) - nft_unregister_flowtable_net_hooks(net, &flowtable->hook_list); + __nft_unregister_flowtable_net_hooks(net, &flowtable->hook_list, + true); } static void __nft_release_hooks(struct net *net) -- 2.30.2