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 C1FAFCE79CE for ; Wed, 20 Sep 2023 12:48:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235387AbjITMsb (ORCPT ); Wed, 20 Sep 2023 08:48:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43288 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235385AbjITMsa (ORCPT ); Wed, 20 Sep 2023 08:48:30 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 61CF183 for ; Wed, 20 Sep 2023 05:48:24 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AF081C433CA; Wed, 20 Sep 2023 12:48:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1695214104; bh=m7UiFBix/W4SKKHue1vs3b4RV81hz8kWYiLz6cqI/2k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NoyZvgrndm/G3BQnTsxF/5l3D+MbiB+2RedV4nSvus6csyayc/LDdbd9IJWladUia 8Fdc+gXmUMQ9bD2b6uIx03+evVYeKjcK9e7HWloUgS3x3A2T+Vg+QkKg+60Yrvxpca LGa5PbGWFufi+jz8pbBOD35dSxRNOQhQAP/4FR44= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Pablo Neira Ayuso , Florian Westphal , Sasha Levin Subject: [PATCH 5.15 088/110] netfilter: nf_tables: fix GC transaction races with netns and netlink event exit path Date: Wed, 20 Sep 2023 13:32:26 +0200 Message-ID: <20230920112833.708799150@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230920112830.377666128@linuxfoundation.org> References: <20230920112830.377666128@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Pablo Neira Ayuso [ Upstream commit 6a33d8b73dfac0a41f3877894b38082bd0c9a5bc ] Netlink event path is missing a synchronization point with GC transactions. Add GC sequence number update to netns release path and netlink event path, any GC transaction losing race will be discarded. Fixes: 5f68718b34a5 ("netfilter: nf_tables: GC transaction API to avoid race with control plane") Signed-off-by: Pablo Neira Ayuso Signed-off-by: Florian Westphal Signed-off-by: Sasha Levin --- net/netfilter/nf_tables_api.c | 36 +++++++++++++++++++++++++++++++---- 1 file changed, 32 insertions(+), 4 deletions(-) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 75b04c01f7b81..3e17d2403d899 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -9202,6 +9202,22 @@ static void nft_set_commit_update(struct list_head *set_update_list) } } +static unsigned int nft_gc_seq_begin(struct nftables_pernet *nft_net) +{ + unsigned int gc_seq; + + /* Bump gc counter, it becomes odd, this is the busy mark. */ + gc_seq = READ_ONCE(nft_net->gc_seq); + WRITE_ONCE(nft_net->gc_seq, ++gc_seq); + + return gc_seq; +} + +static void nft_gc_seq_end(struct nftables_pernet *nft_net, unsigned int gc_seq) +{ + WRITE_ONCE(nft_net->gc_seq, ++gc_seq); +} + static int nf_tables_commit(struct net *net, struct sk_buff *skb) { struct nftables_pernet *nft_net = nft_pernet(net); @@ -9287,9 +9303,7 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb) WRITE_ONCE(nft_net->base_seq, base_seq); - /* Bump gc counter, it becomes odd, this is the busy mark. */ - gc_seq = READ_ONCE(nft_net->gc_seq); - WRITE_ONCE(nft_net->gc_seq, ++gc_seq); + gc_seq = nft_gc_seq_begin(nft_net); /* step 3. Start new generation, rules_gen_X now in use. */ net->nft.gencursor = nft_gencursor_next(net); @@ -9480,7 +9494,7 @@ static int nf_tables_commit(struct net *net, struct sk_buff *skb) nf_tables_gen_notify(net, skb, NFT_MSG_NEWGEN); nf_tables_commit_audit_log(&adl, nft_net->base_seq); - WRITE_ONCE(nft_net->gc_seq, ++gc_seq); + nft_gc_seq_end(nft_net, gc_seq); nf_tables_commit_release(net); return 0; @@ -10463,6 +10477,7 @@ static int nft_rcv_nl_event(struct notifier_block *this, unsigned long event, struct net *net = n->net; unsigned int deleted; bool restart = false; + unsigned int gc_seq; if (event != NETLINK_URELEASE || n->protocol != NETLINK_NETFILTER) return NOTIFY_DONE; @@ -10470,6 +10485,9 @@ static int nft_rcv_nl_event(struct notifier_block *this, unsigned long event, nft_net = nft_pernet(net); deleted = 0; mutex_lock(&nft_net->commit_mutex); + + gc_seq = nft_gc_seq_begin(nft_net); + if (!list_empty(&nf_tables_destroy_list)) nf_tables_trans_destroy_flush_work(); again: @@ -10492,6 +10510,8 @@ static int nft_rcv_nl_event(struct notifier_block *this, unsigned long event, if (restart) goto again; } + nft_gc_seq_end(nft_net, gc_seq); + mutex_unlock(&nft_net->commit_mutex); return NOTIFY_DONE; @@ -10529,12 +10549,20 @@ static void __net_exit nf_tables_pre_exit_net(struct net *net) static void __net_exit nf_tables_exit_net(struct net *net) { struct nftables_pernet *nft_net = nft_pernet(net); + unsigned int gc_seq; mutex_lock(&nft_net->commit_mutex); + + gc_seq = nft_gc_seq_begin(nft_net); + if (!list_empty(&nft_net->commit_list) || !list_empty(&nft_net->module_list)) __nf_tables_abort(net, NFNL_ABORT_NONE); + __nft_release_tables(net); + + nft_gc_seq_end(nft_net, gc_seq); + mutex_unlock(&nft_net->commit_mutex); WARN_ON_ONCE(!list_empty(&nft_net->tables)); WARN_ON_ONCE(!list_empty(&nft_net->module_list)); -- 2.40.1