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 63712CCA47C for ; Tue, 5 Jul 2022 12:00:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232720AbiGEMAv (ORCPT ); Tue, 5 Jul 2022 08:00:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42336 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232880AbiGEMAW (ORCPT ); Tue, 5 Jul 2022 08:00:22 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0302B18345; Tue, 5 Jul 2022 05:00:18 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 973A66174B; Tue, 5 Jul 2022 12:00:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A8CFBC341CF; Tue, 5 Jul 2022 12:00:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1657022417; bh=vsaObZd+iZWcxwNohc0sJZuInhfDdn+IkzqXWqIs19g=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VPSaSnGxrc5Z/vaWbf60bTZLyJ0hhkJ91Rm35XTphygWFV3F8WTfXPJX/iEGr5JSH ypKK80MgRNhOwRABNZQ8XvC8wYo/HE2vl6nHPpp56J/pFvbIWItXDzEFSUh5c4NxZX vUKhOZAq3VTomN754stumfecnYEiFnQ90e/LmCv8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pablo Neira Ayuso Subject: [PATCH 4.9 09/29] netfilter: nft_dynset: restore set element counter when failing to update Date: Tue, 5 Jul 2022 13:57:50 +0200 Message-Id: <20220705115606.021430942@linuxfoundation.org> X-Mailer: git-send-email 2.37.0 In-Reply-To: <20220705115605.742248854@linuxfoundation.org> References: <20220705115605.742248854@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Pablo Neira Ayuso commit 05907f10e235680cc7fb196810e4ad3215d5e648 upstream. This patch fixes a race condition. nft_rhash_update() might fail for two reasons: - Element already exists in the hashtable. - Another packet won race to insert an entry in the hashtable. In both cases, new() has already bumped the counter via atomic_add_unless(), therefore, decrement the set element counter. Fixes: 22fe54d5fefc ("netfilter: nf_tables: add support for dynamic set updates") Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman --- net/netfilter/nft_set_hash.c | 2 ++ 1 file changed, 2 insertions(+) --- a/net/netfilter/nft_set_hash.c +++ b/net/netfilter/nft_set_hash.c @@ -121,6 +121,7 @@ static bool nft_hash_update(struct nft_s /* Another cpu may race to insert the element with the same key */ if (prev) { nft_set_elem_destroy(set, he, true); + atomic_dec(&set->nelems); he = prev; } @@ -130,6 +131,7 @@ out: err2: nft_set_elem_destroy(set, he, true); + atomic_dec(&set->nelems); err1: return false; }