From patchwork Mon Sep 12 12:41:00 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tetsuo Handa X-Patchwork-Id: 12973622 X-Patchwork-Delegate: kuba@kernel.org 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 AAC34ECAAD5 for ; Mon, 12 Sep 2022 12:41:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229610AbiILMlK (ORCPT ); Mon, 12 Sep 2022 08:41:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47150 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229786AbiILMlJ (ORCPT ); Mon, 12 Sep 2022 08:41:09 -0400 Received: from www262.sakura.ne.jp (www262.sakura.ne.jp [202.181.97.72]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7F07F17AB8 for ; Mon, 12 Sep 2022 05:41:04 -0700 (PDT) Received: from fsav411.sakura.ne.jp (fsav411.sakura.ne.jp [133.242.250.110]) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTP id 28CCf1gA036892; Mon, 12 Sep 2022 21:41:01 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Received: from www262.sakura.ne.jp (202.181.97.72) by fsav411.sakura.ne.jp (F-Secure/fsigk_smtp/550/fsav411.sakura.ne.jp); Mon, 12 Sep 2022 21:41:00 +0900 (JST) X-Virus-Status: clean(F-Secure/fsigk_smtp/550/fsav411.sakura.ne.jp) Received: from [192.168.1.9] (M106072142033.v4.enabler.ne.jp [106.72.142.33]) (authenticated bits=0) by www262.sakura.ne.jp (8.15.2/8.15.2) with ESMTPSA id 28CCf0oc036889 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NO); Mon, 12 Sep 2022 21:41:00 +0900 (JST) (envelope-from penguin-kernel@I-love.SAKURA.ne.jp) Message-ID: <8c86a1bb-9c43-b02e-cf93-e098b158ee8c@I-love.SAKURA.ne.jp> Date: Mon, 12 Sep 2022 21:41:00 +0900 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.2.2 Subject: [PATCH] netfilter: nf_tables: fix nft_counters_enabled underflow at nf_tables_addchain() Content-Language: en-US To: Pablo Neira Ayuso , Jozsef Kadlecsik , Florian Westphal References: <000000000000a9172705e7ffef2e@google.com> Cc: syzbot , syzkaller-bugs@googlegroups.com, netfilter-devel@vger.kernel.org, coreteam@netfilter.org, Network Development From: Tetsuo Handa In-Reply-To: <000000000000a9172705e7ffef2e@google.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org syzbot is reporting underflow of nft_counters_enabled counter at nf_tables_addchain() [1], for commit 43eb8949cfdffa76 ("netfilter: nf_tables: do not leave chain stats enabled on error") missed that nf_tables_chain_destroy() after nft_basechain_init() in the error path of nf_tables_addchain() decrements the counter because nft_basechain_init() makes nft_is_base_chain() return true by setting NFT_CHAIN_BASE flag. Increment the counter immediately after returning from nft_basechain_init(). Link: https://syzkaller.appspot.com/bug?extid=b5d82a651b71cd8a75ab [1] Reported-by: syzbot Signed-off-by: Tetsuo Handa Tested-by: syzbot Fixes: 43eb8949cfdffa76 ("netfilter: nf_tables: do not leave chain stats enabled on error") --- net/netfilter/nf_tables_api.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 816052089b33..e062754dc6cc 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -2197,7 +2197,6 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask, struct netlink_ext_ack *extack) { const struct nlattr * const *nla = ctx->nla; - struct nft_stats __percpu *stats = NULL; struct nft_table *table = ctx->table; struct nft_base_chain *basechain; struct net *net = ctx->net; @@ -2212,6 +2211,7 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask, return -EOVERFLOW; if (nla[NFTA_CHAIN_HOOK]) { + struct nft_stats __percpu *stats = NULL; struct nft_chain_hook hook; if (flags & NFT_CHAIN_BINDING) @@ -2245,6 +2245,8 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask, kfree(basechain); return err; } + if (stats) + static_branch_inc(&nft_counters_enabled); } else { if (flags & NFT_CHAIN_BASE) return -EINVAL; @@ -2319,9 +2321,6 @@ static int nf_tables_addchain(struct nft_ctx *ctx, u8 family, u8 genmask, goto err_unregister_hook; } - if (stats) - static_branch_inc(&nft_counters_enabled); - table->use++; return 0;