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 2C963C6FA8A for ; Mon, 12 Sep 2022 12:45:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229693AbiILMpH (ORCPT ); Mon, 12 Sep 2022 08:45:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50608 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229588AbiILMpF (ORCPT ); Mon, 12 Sep 2022 08:45:05 -0400 Received: from mail.netfilter.org (mail.netfilter.org [217.70.188.207]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id D536112A9E; Mon, 12 Sep 2022 05:45:02 -0700 (PDT) Date: Mon, 12 Sep 2022 14:44:58 +0200 From: Pablo Neira Ayuso To: Tetsuo Handa Cc: Jozsef Kadlecsik , Florian Westphal , syzbot , syzkaller-bugs@googlegroups.com, netfilter-devel@vger.kernel.org, coreteam@netfilter.org, Network Development Subject: Re: [PATCH] netfilter: nf_tables: fix nft_counters_enabled underflow at nf_tables_addchain() Message-ID: References: <000000000000a9172705e7ffef2e@google.com> <8c86a1bb-9c43-b02e-cf93-e098b158ee8c@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <8c86a1bb-9c43-b02e-cf93-e098b158ee8c@I-love.SAKURA.ne.jp> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Sep 12, 2022 at 09:41:00PM +0900, Tetsuo Handa wrote: > 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(). Patch LGTM, thanks > 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; > -- > 2.18.4 >