From patchwork Tue Apr 26 08:22:01 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 567864 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 19EF7C433EF for ; Tue, 26 Apr 2022 08:55:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345784AbiDZI60 (ORCPT ); Tue, 26 Apr 2022 04:58:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52812 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245020AbiDZI5Y (ORCPT ); Tue, 26 Apr 2022 04:57:24 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EB1EA81677; Tue, 26 Apr 2022 01:41:57 -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 ams.source.kernel.org (Postfix) with ESMTPS id A77ABB81CED; Tue, 26 Apr 2022 08:41:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1C329C385A4; Tue, 26 Apr 2022 08:41:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1650962515; bh=Oaa1kYDZlmNoZlnAkZ1ogI20WNPdZk//Lu5Kqqcgd04=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qDSjBdQiiozyNJclvsVg7ae8mw4mTWIjCwKHUWIK+FnlcRv6W9EQDNA05Wb7Hb8k5 lLUdBMW1v/B9SQLZz7todEgZtBt8ScWWod1BebfZhAMBM+3QLMm+HbhT+Y8f+DctDk HQ1Yd9C/iQ5HMI8nU6eNzNMgmcMxbCuezPCc1kQ8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, kernel test robot , Florian Westphal , Pablo Neira Ayuso Subject: [PATCH 5.15 120/124] netfilter: nft_ct: fix use after free when attaching zone template Date: Tue, 26 Apr 2022 10:22:01 +0200 Message-Id: <20220426081750.701058603@linuxfoundation.org> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220426081747.286685339@linuxfoundation.org> References: <20220426081747.286685339@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Florian Westphal commit 34243b9ec856309339172b1507379074156947e8 upstream. The conversion erroneously removed the refcount increment. In case we can use the percpu template, we need to increment the refcount, else it will be released when the skb gets freed. In case the slowpath is taken, the new template already has a refcount of 1. Fixes: 719774377622 ("netfilter: conntrack: convert to refcount_t api") Reported-by: kernel test robot Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso Signed-off-by: Greg Kroah-Hartman --- net/netfilter/nft_ct.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/net/netfilter/nft_ct.c +++ b/net/netfilter/nft_ct.c @@ -260,9 +260,12 @@ static void nft_ct_set_zone_eval(const s ct = this_cpu_read(nft_ct_pcpu_template); if (likely(refcount_read(&ct->ct_general.use) == 1)) { + refcount_inc(&ct->ct_general.use); nf_ct_zone_add(ct, &zone); } else { - /* previous skb got queued to userspace */ + /* previous skb got queued to userspace, allocate temporary + * one until percpu template can be reused. + */ ct = nf_ct_tmpl_alloc(nft_net(pkt), &zone, GFP_ATOMIC); if (!ct) { regs->verdict.code = NF_DROP;