From patchwork Tue Aug 10 12:59:20 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Skripkin X-Patchwork-Id: 12428865 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 X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AD6A0C4320A for ; Tue, 10 Aug 2021 12:59:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9322B60FC4 for ; Tue, 10 Aug 2021 12:59:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241054AbhHJM77 (ORCPT ); Tue, 10 Aug 2021 08:59:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42720 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239188AbhHJM77 (ORCPT ); Tue, 10 Aug 2021 08:59:59 -0400 Received: from mail-lj1-x22a.google.com (mail-lj1-x22a.google.com [IPv6:2a00:1450:4864:20::22a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3175CC0613D3; Tue, 10 Aug 2021 05:59:37 -0700 (PDT) Received: by mail-lj1-x22a.google.com with SMTP id m9so28921624ljp.7; Tue, 10 Aug 2021 05:59:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=C8ukQa3sXo+DBl8G/r0rlRb+zkXrtXj0fbs8AcpdmLM=; b=BeR0m3pZrkVng8z/cHE1HhRzPFWun7v6JeIPJr7i2Y0ic0pnr5hNFoZdBlYDJL0Xg+ RoM7hPyLnx0zqG27UL1O7qbP3yuUFooPWRR77qltiO/ij40qu7ZMsF8Mpa0Lw+/jdrQ/ fji0Tzfl/hUi1cU9j/u0iptIowVN2aNGLtqe7WzwL58Tu4aI83G5mGeJBzxrO7GkyjdE wR4IB0POHiMTq6k2wTVyjghI9zGVJPRxWwmb7PbulzaU3YcwvLAUZvZSDEApQVWyvvp8 sawq7BSsw+rr64tuzNRMlSJQdgFQB68FAg3Kkq7vHCcApuV0zocldjj0uPpVts2MAh7j 1h9w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=C8ukQa3sXo+DBl8G/r0rlRb+zkXrtXj0fbs8AcpdmLM=; b=fjeSbIHsOI9jEWIwwTHn4CtpOLUJ3Jxy8jbsV6wNlq3pjxCStOOgtTp+uF3gMsrjGr Q7Xu6koICRGM/8NaYvzFOzBvsUgIjsiIBWHBJ3O8NrjJ7PpHy41WjPXthRdsopyOaodO K5YkMJQN+IflPtuL/4KNoqwWH1uZuYGibIhzYYAJ8F5a+EmRpCw0MMHfnluH+IwQarE6 rZNz8egvY2x+SWxTt8d7+9DI/zpV+dXP93ye6Di3OJsTx3ZPMoW79XAQ/4xYTFLmGB0b 0uxJclebv+f5tbaAPS09Iw7oVV/mGYuQEFhiI9SmdsmXUE2su5zZyG1DECpntROGqvHm Lb3w== X-Gm-Message-State: AOAM531IjXpLRn0Oh/jMO56gYoBo4gK/4C34oCgZlmrI4x1z4YkAdPWp 7qaZ2Wqmw24A78CqV5tuGqc= X-Google-Smtp-Source: ABdhPJyXKs6dOhzi+KmIRhTXSLCqmlcLAcEQglehQFPDp/eginYv8FRijzR7lGhqlXzh/oYaSjmoog== X-Received: by 2002:a2e:8250:: with SMTP id j16mr19645493ljh.164.1628600375545; Tue, 10 Aug 2021 05:59:35 -0700 (PDT) Received: from localhost.localdomain ([46.235.67.232]) by smtp.gmail.com with ESMTPSA id m12sm2039397lfh.182.2021.08.10.05.59.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Aug 2021 05:59:35 -0700 (PDT) From: Pavel Skripkin To: pablo@netfilter.org, kadlec@netfilter.org, fw@strlen.de, davem@davemloft.net Cc: netfilter-devel@vger.kernel.org, coreteam@netfilter.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Pavel Skripkin , syzbot+649e339fa6658ee623d3@syzkaller.appspotmail.com Subject: [PATCH v2] netfilter: protect nft_ct_pcpu_template_refcnt with mutex Date: Tue, 10 Aug 2021 15:59:20 +0300 Message-Id: <20210810125920.23187-1-paskripkin@gmail.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210810125523.15312-1-paskripkin@gmail.com> References: <20210810125523.15312-1-paskripkin@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Syzbot hit use-after-free in nf_tables_dump_sets. The problem was in missing lock protection for nft_ct_pcpu_template_refcnt. Before commit f102d66b335a ("netfilter: nf_tables: use dedicated mutex to guard transactions") all transactions were serialized by global mutex, but then global mutex was changed to local per netnamespace commit_mutex. This change causes use-after-free bug, when 2 netnamespaces concurently changing nft_ct_pcpu_template_refcnt without proper locking. Fix it by adding nft_ct_pcpu_mutex and protect all nft_ct_pcpu_template_refcnt changes with it. Fixes: f102d66b335a ("netfilter: nf_tables: use dedicated mutex to guard transactions") Reported-and-tested-by: syzbot+649e339fa6658ee623d3@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin Acked-by: Florian Westphal --- Changes in v2: Fixed typo in title: netfiler -> netfilter --- net/netfilter/nft_ct.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/net/netfilter/nft_ct.c b/net/netfilter/nft_ct.c index 337e22d8b40b..99b1de14ff7e 100644 --- a/net/netfilter/nft_ct.c +++ b/net/netfilter/nft_ct.c @@ -41,6 +41,7 @@ struct nft_ct_helper_obj { #ifdef CONFIG_NF_CONNTRACK_ZONES static DEFINE_PER_CPU(struct nf_conn *, nft_ct_pcpu_template); static unsigned int nft_ct_pcpu_template_refcnt __read_mostly; +static DEFINE_MUTEX(nft_ct_pcpu_mutex); #endif static u64 nft_ct_get_eval_counter(const struct nf_conn_counter *c, @@ -525,8 +526,10 @@ static void __nft_ct_set_destroy(const struct nft_ctx *ctx, struct nft_ct *priv) #endif #ifdef CONFIG_NF_CONNTRACK_ZONES case NFT_CT_ZONE: + mutex_lock(&nft_ct_pcpu_mutex); if (--nft_ct_pcpu_template_refcnt == 0) nft_ct_tmpl_put_pcpu(); + mutex_unlock(&nft_ct_pcpu_mutex); break; #endif default: @@ -564,9 +567,13 @@ static int nft_ct_set_init(const struct nft_ctx *ctx, #endif #ifdef CONFIG_NF_CONNTRACK_ZONES case NFT_CT_ZONE: - if (!nft_ct_tmpl_alloc_pcpu()) + mutex_lock(&nft_ct_pcpu_mutex); + if (!nft_ct_tmpl_alloc_pcpu()) { + mutex_unlock(&nft_ct_pcpu_mutex); return -ENOMEM; + } nft_ct_pcpu_template_refcnt++; + mutex_unlock(&nft_ct_pcpu_mutex); len = sizeof(u16); break; #endif