Re: [TLS] TLS Next Proto negotiation
Marsh Ray <marsh@extendedsubset.com> Thu, 21 July 2011 22:06 UTC
Return-Path: <marsh@extendedsubset.com>
X-Original-To: tls@ietfa.amsl.com
Delivered-To: tls@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 8C9C921F8579 for <tls@ietfa.amsl.com>; Thu, 21 Jul 2011 15:06:23 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.599
X-Spam-Level:
X-Spam-Status: No, score=-2.599 tagged_above=-999 required=5 tests=[BAYES_00=-2.599]
Received: from mail.ietf.org ([64.170.98.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id eEv+r5Rq6tF1 for <tls@ietfa.amsl.com>; Thu, 21 Jul 2011 15:06:23 -0700 (PDT)
Received: from mho-02-ewr.mailhop.org (mho-04-ewr.mailhop.org [204.13.248.74]) by ietfa.amsl.com (Postfix) with ESMTP id 17D4021F8576 for <tls@ietf.org>; Thu, 21 Jul 2011 15:06:23 -0700 (PDT)
Received: from xs01.extendedsubset.com ([69.164.193.58]) by mho-02-ewr.mailhop.org with esmtpa (Exim 4.72) (envelope-from <marsh@extendedsubset.com>) id 1Qk1Nu-000GKU-Lj; Thu, 21 Jul 2011 22:06:22 +0000
Received: from [192.168.1.15] (localhost [127.0.0.1]) by xs01.extendedsubset.com (Postfix) with ESMTP id 293EC6073; Thu, 21 Jul 2011 22:06:21 +0000 (UTC)
X-Mail-Handler: MailHop Outbound by DynDNS
X-Originating-IP: 69.164.193.58
X-Report-Abuse-To: abuse@dyndns.com (see http://www.dyndns.com/services/mailhop/outbound_abuse.html for abuse reporting information)
X-MHO-User: U2FsdGVkX184VltCkkMv40a8478i96BoATtilY5fdB4=
Message-ID: <4E28A2D5.6000907@extendedsubset.com>
Date: Thu, 21 Jul 2011 17:06:13 -0500
From: Marsh Ray <marsh@extendedsubset.com>
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.18) Gecko/20110617 Thunderbird/3.1.11
MIME-Version: 1.0
To: Adam Langley <agl@google.com>
References: <20110718122259.8995.qmail@f4mail-235-121.rediffmail.com> <CAL9PXLyyjsYvetqUjuO1UY6GGNay6dKK5Ae5bj8SCP7_HPg_2g@mail.gmail.com>
In-Reply-To: <CAL9PXLyyjsYvetqUjuO1UY6GGNay6dKK5Ae5bj8SCP7_HPg_2g@mail.gmail.com>
Content-Type: text/plain; charset="ISO-8859-1"; format="flowed"
Content-Transfer-Encoding: 7bit
Cc: tls <tls@ietf.org>
Subject: Re: [TLS] TLS Next Proto negotiation
X-BeenThere: tls@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
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/options/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, 21 Jul 2011 22:06:23 -0000
On 07/18/2011 07:43 AM, Adam Langley wrote: > > http://tools.ietf.org/html/draft-agl-tls-nextprotoneg-02 The server needs to see the client's NextProtocol message to know what protocol will be in use. But when a session is resumed, the server sends the Finished message before the client. Some app protocols have the server send the first application data, e.g., "username: ". If such an app protocol is a possibility, doesn't the use of NPN introduce an extra round-trip delay in case of session resumption? Also, since the semantics of NPN apply explicitly to the connection (rather than the session or connection state), perhaps the use of NPN ought to be contingent on the successful negotiation of RFC 5746 Renegotiation Indication. Multiplexing multiple protocols from same server port are likely to provide additional opportunities for an attacker to put the server in a state where it is willing to accept a renegotiating ClientHello. It will also provide more ways for an attacker to have the server echo back chosen plaintext to be interpreted as HTTP response headers (or other protocols could be attacked). - Marsh
- [TLS] TLS Next Proto negotiation gswaru
- Re: [TLS] TLS Next Proto negotiation Adam Langley
- Re: [TLS] TLS Next Proto negotiation Adam Langley
- Re: [TLS] TLS Next Proto negotiation Marsh Ray
- Re: [TLS] TLS Next Proto negotiation Adam Langley