From patchwork Tue Aug 10 12:55:23 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Skripkin X-Patchwork-Id: 494795 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=ham 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 223F4C4320A for ; Tue, 10 Aug 2021 12:55:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 017BA60F56 for ; Tue, 10 Aug 2021 12:55:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239083AbhHJMzu (ORCPT ); Tue, 10 Aug 2021 08:55:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41694 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233590AbhHJMzt (ORCPT ); Tue, 10 Aug 2021 08:55:49 -0400 Received: from mail-lf1-x12a.google.com (mail-lf1-x12a.google.com [IPv6:2a00:1450:4864:20::12a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8ED71C0613D3; Tue, 10 Aug 2021 05:55:27 -0700 (PDT) Received: by mail-lf1-x12a.google.com with SMTP id g13so41263944lfj.12; Tue, 10 Aug 2021 05:55:27 -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:mime-version :content-transfer-encoding; bh=4rViaCUp03F0sOMlLIrr/48hOom8gf9ywmMtY7hOCEw=; b=QhDrGZLyjbA+pSrCNOia22rq2ksofFcAAHQdCK9zOvnrwjwdvm8gX4oUvEzmyfEb+e wiTutgnsFTzVv1Bi6DqP1lenvA2AEqpS83J1C+i4EaBai8teuEnfETejvbRfk+/RGWjf JXe4+npxD9GWeetIrXD5uN2AKxaa3uvSCJzZ+ZU+UtEODLVifkAVYPSLgKeTAgXyjrKb eAkTYnSjrkuMej/bG4d7vIHR4QVu0dfgUYs+/ZiR3Mxak1wSu4CnJCMI/9cZPWzrJtsL Y7o+1TYR+rYMc4eaJD1TioIawKlGr+l5l8iGo5qV4ytqaGrkVuD3vPostkfucpRHHIsm NGVQ== 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:mime-version :content-transfer-encoding; bh=4rViaCUp03F0sOMlLIrr/48hOom8gf9ywmMtY7hOCEw=; b=uCQQwnvYG+BQLMMRIAwv7oZ90U2gWBc9HvHh37VwlsYKQxxOr1uexu9SKugfLwrIYN xvFX6v3iuLDyZ3yVzAS2v46QoATs90nKabkGRvRy6BQOu9Dskew3qkO65f4P/kSSkiZO cbZYz0+wzLM00xGSmPxhnaH/WIBwlXb/Nh5biKHnt6TsVme31wqS3B9WMm5dv8FCkyry TGUqWb+UyNitMkoUEt6A9pY8F7dPD8uy2+jNil9t8AHVX0W+0p+Rvj8FTTu+HTcfAHkl aTueXhdO8ZumzMY4VuqrLOEbcq3LNU2En2MUwQYhcqqYPdgtTA9TPQ1TDmEFN4YBeBWv 1WIg== X-Gm-Message-State: AOAM5337At97m+ZVWVeLAqJvOi/VGk7QMGD7h0PXQf6liQi+8t75AjXd vthTljka3Wul5d9JZUOnNuI= X-Google-Smtp-Source: ABdhPJxVRsKFgx2m5ReTxzKsAj+BWBLyWiKUWBNi+p/47kWiw91JrwzOve3y9nUUzr9UpTQYPMXCPg== X-Received: by 2002:a05:6512:470:: with SMTP id x16mr22072229lfd.497.1628600125867; Tue, 10 Aug 2021 05:55:25 -0700 (PDT) Received: from localhost.localdomain ([46.235.67.232]) by smtp.gmail.com with ESMTPSA id k17sm1873341ljm.7.2021.08.10.05.55.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 10 Aug 2021 05:55:25 -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] netfiler: protect nft_ct_pcpu_template_refcnt with mutex Date: Tue, 10 Aug 2021 15:55:23 +0300 Message-Id: <20210810125523.15312-1-paskripkin@gmail.com> X-Mailer: git-send-email 2.32.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.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 --- 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