From patchwork Mon Sep 11 06:23:38 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Po-Hsu Lin X-Patchwork-Id: 812226 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=lists.ubuntu.com (client-ip=91.189.94.19; helo=huckleberry.canonical.com; envelope-from=kernel-team-bounces@lists.ubuntu.com; receiver=) Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 3xrHty2F3Cz9sBZ; Mon, 11 Sep 2017 16:23:54 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.86_2) (envelope-from ) id 1drI8K-0008OL-E4; Mon, 11 Sep 2017 06:23:48 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:128) (Exim 4.86_2) (envelope-from ) id 1drI8I-0008Nj-QZ for kernel-team@lists.ubuntu.com; Mon, 11 Sep 2017 06:23:46 +0000 Received: from mail-pg0-f69.google.com ([74.125.83.69]) by youngberry.canonical.com with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1drI8I-00051X-FC for kernel-team@lists.ubuntu.com; Mon, 11 Sep 2017 06:23:46 +0000 Received: by mail-pg0-f69.google.com with SMTP id d8so15239404pgt.1 for ; Sun, 10 Sep 2017 23:23:46 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references; bh=1ZDWEzHb3/b+gqRMThnuJU4Egq996oYpS4KUiFVsmCc=; b=JYcT72u0oyvHriQDbgFwjoM/ORHiwQuUIh6fDdAVsTrkwaFizOIv7DnUeRmsfnS1TM ohkoc6H4faAP9D+Rop9wTeW7ZH/0GIzVLZuizJZebYxtS2Gr/P+76kpXTMI3Y9aeM/fB g3RY23Mladwzv5I5jfOGhq15gYSxxsTOpbtLu4SssA/eoo2ZZbiGDWGo481B+4nyoTUz XqCHFt5pTk0oqjSekxVxYdgKeyHz0J0aBJP88R5Q4TPgQBCLJFzxagvxdKxv1F8N3oC8 DewkZZm/a+HVc1frPPJXuu/n99M+AvovTMqxpNo9L/5VaWygFQDhZeNOuVQ1+bgs7gt2 CBhA== X-Gm-Message-State: AHPjjUhFbmJPXSl0YE13+OVWx2dZmwVVsNuvR6l+D22NJk+/iD9ktJ+W uApBkPr03Jg68sJ77tYmHaGnoKNZCsPJ2fpXyU9YOFxUhCHJfgjkoML/iGqQ6z/qEgr6cEDqsli OACBWDy5ygUm+X+YPKRFl0aJWxshr25rO X-Received: by 10.98.87.23 with SMTP id l23mr11005141pfb.77.1505111025033; Sun, 10 Sep 2017 23:23:45 -0700 (PDT) X-Google-Smtp-Source: ADKCNb6fexHEIwbCJaZ/oYETAfyiKr9BUsgUxK7W3vXmReoayonM9Mj8MKVbClqsEyYCSRCJ35yADA== X-Received: by 10.98.87.23 with SMTP id l23mr11005135pfb.77.1505111024852; Sun, 10 Sep 2017 23:23:44 -0700 (PDT) Received: from localhost.localdomain ([175.41.48.77]) by smtp.gmail.com with ESMTPSA id e185sm2929967pfg.142.2017.09.10.23.23.43 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 10 Sep 2017 23:23:44 -0700 (PDT) From: Po-Hsu Lin To: kernel-team@lists.ubuntu.com Subject: [CVE-2017-14106][T/X/Z SRU][PATCH] tcp: initialize rcv_mss to TCP_MIN_MSS instead of 0 Date: Mon, 11 Sep 2017 14:23:38 +0800 Message-Id: <20170911062338.9825-2-po-hsu.lin@canonical.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170911062338.9825-1-po-hsu.lin@canonical.com> References: <20170911062338.9825-1-po-hsu.lin@canonical.com> X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.20 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: "kernel-team" From: Wei Wang CVE-2017-14106 When tcp_disconnect() is called, inet_csk_delack_init() sets icsk->icsk_ack.rcv_mss to 0. This could potentially cause tcp_recvmsg() => tcp_cleanup_rbuf() => __tcp_select_window() call path to have division by 0 issue. So this patch initializes rcv_mss to TCP_MIN_MSS instead of 0. Reported-by: Andrey Konovalov Signed-off-by: Wei Wang Signed-off-by: Eric Dumazet Signed-off-by: Neal Cardwell Signed-off-by: Yuchung Cheng Signed-off-by: David S. Miller (cherry picked from commit 499350a5a6e7512d9ed369ed63a4244b6536f4f8) Signed-off-by: Po-Hsu Lin Acked-by: Stefan Bader Acked-by: Colin Ian King --- net/ipv4/tcp.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 16b5118..46c45a0 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2202,6 +2202,10 @@ int tcp_disconnect(struct sock *sk, int flags) tcp_set_ca_state(sk, TCP_CA_Open); tcp_clear_retrans(tp); inet_csk_delack_init(sk); + /* Initialize rcv_mss to TCP_MIN_MSS to avoid division by 0 + * issue in __tcp_select_window() + */ + icsk->icsk_ack.rcv_mss = TCP_MIN_MSS; tcp_init_send_head(sk); memset(&tp->rx_opt, 0, sizeof(tp->rx_opt)); __sk_dst_reset(sk);