Re: [TLS] [Syslog] Missing dead peer detection in DTLS
"tom.petch" <cfinss@dial.pipex.com> Thu, 30 July 2009 14:33 UTC
Return-Path: <cfinss@dial.pipex.com>
X-Original-To: tls@core3.amsl.com
Delivered-To: tls@core3.amsl.com
Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id B5BE13A700A; Thu, 30 Jul 2009 07:33:28 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.457
X-Spam-Level:
X-Spam-Status: No, score=-2.457 tagged_above=-999 required=5 tests=[AWL=0.098, BAYES_00=-2.599, DATE_IN_PAST_03_06=0.044]
Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id A2ZKdsSUx7Cp; Thu, 30 Jul 2009 07:33:26 -0700 (PDT)
Received: from mk-outboundfilter-2.mail.uk.tiscali.com (mk-outboundfilter-2.mail.uk.tiscali.com [212.74.114.38]) by core3.amsl.com (Postfix) with ESMTP id 1489F3A6C50; Thu, 30 Jul 2009 07:33:25 -0700 (PDT)
X-Trace: 237566643/mk-outboundfilter-2.mail.uk.tiscali.com/PIPEX/$PIPEX-ACCEPTED/pipex-customers/62.188.105.16/None/cfinss@dial.pipex.com
X-SBRS: None
X-RemoteIP: 62.188.105.16
X-IP-MAIL-FROM: cfinss@dial.pipex.com
X-SMTP-AUTH:
X-MUA: Microsoft Outlook Express 6.00.2800.1106Produced By Microsoft MimeOLE V6.00.2800.1106
X-IP-BHB: Once
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-Anti-Spam-Result: ArEGAPtLcUo+vGkQ/2dsb2JhbABEgmk8jFjCdQIHgi6BWgU
X-IronPort-AV: E=Sophos;i="4.43,295,1246834800"; d="scan'208";a="237566643"
X-IP-Direction: IN
Received: from 1cust16.tnt2.lnd9.gbr.da.uu.net (HELO allison) ([62.188.105.16]) by smtp.pipex.tiscali.co.uk with SMTP; 30 Jul 2009 15:33:23 +0100
Message-ID: <000401ca111a$3bb01da0$0601a8c0@allison>
From: "tom.petch" <cfinss@dial.pipex.com>
To: Gerhard Muenz <muenz@net.in.tum.de>, syslog@ietf.org, ipfix@ietf.org, tls@ietf.org
References: <4A6EB9BB.9040002@net.in.tum.de>
Date: Thu, 30 Jul 2009 11:44:11 +0200
MIME-Version: 1.0
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 8bit
X-Priority: 3
X-MSMail-Priority: Normal
X-Mailer: Microsoft Outlook Express 6.00.2800.1106
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106
Cc: Michael Tuexen <tuexen@fh-muenster.de>, Daniel Mentz <mentz@in.tum.de>
Subject: Re: [TLS] [Syslog] Missing dead peer detection in DTLS
X-BeenThere: tls@ietf.org
X-Mailman-Version: 2.1.9
Precedence: list
Reply-To: "tom.petch" <cfinss@dial.pipex.com>
List-Id: "This is the mailing list for the Transport Layer Security working group of the IETF." <tls.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/listinfo/tls>, <mailto:tls-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/tls>
List-Post: <mailto:tls@ietf.org>
List-Help: <mailto:tls-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/tls>, <mailto:tls-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 30 Jul 2009 14:33:28 -0000
Gerhard Thank you for pointing this out; it had escaped me. What I had thought though was that the lack of flow control with DTLS over UDP is a problem, and that the lack of this with syslog over UDP led the syslog RFC [RFC5424] to make syslog over TLS the RECOMMENDED transport, not, as might be expected, syslog over UDP. This in turn led me to expect that syslog over DTLS over UDP would not be acceptable to the IESG, rather that syslog over DTLS over SCTP would become the RECOMMENDED transport. So; several thoughts. This is an update to the extensions RFC, RFC4366, which itself is being updated by the TLS working group (hence my addition of them to the list) and I would much rather have one extensions RFC rather than several. This is a good concept and fills a need; perhaps the TLS working group would take this on. Flow control remains an issue which I do not think that this extension addresses. Is this a security exposure? or just, like syslog over UDP, an inconvenient truth? The petch-gerhards draft allows the recipient of the unidirectional flow to initiate the DTLS 'connection', and so enables it to re-establish the connection when anything goes wrong. This would seem an alternative to consider. Tom Petch ----- Original Message ----- From: "Gerhard Muenz" <muenz@net.in.tum.de> To: <syslog@ietf.org>; <ipfix@ietf.org> Cc: "Michael Tuexen" <tuexen@fh-muenster.de>; "Robin Seggelmann" <seggelmann@fh-muenster.de>; "Daniel Mentz" <mentz@in.tum.de> Sent: Tuesday, July 28, 2009 10:41 AM Subject: [Syslog] Missing dead peer detection in DTLS Hi, This mail goes to the ipfix and syslog mailing lists in order to summarize the common issues regarding DTLS. IPFIX specifies support of DTLS as mandatory for transport over UDP and SCTP in RFC5101. In SYSLOG, it is intended to standardize DTLS for transport over UDP. In IPFIX, we have a first implementation of IPFIX-over-DTLS/UDP, and we will have a first implementation of IPFIX-over-DTLS/SCTP very soon. During this implementation effort, we found that the current specification of DTLS/UDP has a severe flaw when used with unidirectional protocols (like IPFIX): The sender cannot recognize if the receiver has crashed and lost the DTLS state. We discuss this issue in a draft: http://tools.ietf.org/html/draft-mentz-ipfix-dtls-recommendations-00 http://www.ietf.org/proceedings/75/slides/ipfix-6.pdf I've had a look at draft-feng-syslog-transport-dtls-01 and draft-petch-gerhards-syslog-transport-dtls-02. It seems that this problem has not yet been covered, although the problem should be the same for SYSLOG. As a solution, the DTLS Heartbeat Extension has been proposed very recently: http://tools.ietf.org/html/draft-seggelmann-tls-dtls-heartbeat-00 A feature patch for OpenSSL is available: http://sctp.fh-muenster.de/dtls-patches.html#features So, I think that we should support this standardization initiative as it solves our problem. For IPFIX and SYSLOG over DTLS/UDP, we then can specify that the DTLS Heartbeat Extension MUST be implemented. Dan suggested to have a single document solving the DTLS issues regarding unidirectional protocols. I think that such a document is not needed if we have DTLS Heartbeat Extension. Regards, Gerhard Dipl.-Ing. Gerhard Münz Chair for Network Architectures and Services (I8) Department of Informatics Technische Universität München Boltzmannstr. 3, 85748 Garching bei München, Germany Phone: +49 89 289-18008 Fax: +49 89 289-18033 E-mail: muenz@net.in.tum.de WWW: http://www.net.in.tum.de/~muenz
- Re: [TLS] [Syslog] Missing dead peer detection in… tom.petch
- Re: [TLS] [Syslog] Missing dead peer detection in… Michael Tuexen
- Re: [TLS] [Syslog] Missing dead peer detection in… tom.petch
- Re: [TLS] [Syslog] Missing dead peer detection in… Michael Tuexen
- Re: [TLS] [Syslog] Missing dead peer detection in… Erick O
- Re: [TLS] [Syslog] Missing dead peer detection in… Michael Tuexen
- Re: [TLS] [Syslog] Missing dead peer detection in… Erick O
- Re: [TLS] [Syslog] Missing dead peer detection in… Erick O