IETF Logo Mail Archive

[MMUSIC] RFC 5245: ice-ufrags of length 256 vs stun maximum username length of 512 bytes

Philipp Hancke <fippo@goodadvice.pages.de> Wed, 14 August 2013 06:54 UTC

Return-Path: <fippo@goodadvice.pages.de>
X-Original-To: mmusic@ietfa.amsl.com
Delivered-To: mmusic@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 99E4521F9AC4 for <mmusic@ietfa.amsl.com>; Tue, 13 Aug 2013 23:54:47 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.999
X-Spam-Level:
X-Spam-Status: No, score=-1.999 tagged_above=-999 required=5 tests=[BAYES_00=-2.599, J_CHICKENPOX_55=0.6]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id waPS3kwKJl9w for <mmusic@ietfa.amsl.com>; Tue, 13 Aug 2013 23:54:43 -0700 (PDT)
Received: from lo.psyced.org (lost.IN.psyced.org [188.40.42.221]) by ietfa.amsl.com (Postfix) with ESMTP id 7A64821F9ACA for <mmusic@ietf.org>; Tue, 13 Aug 2013 23:54:32 -0700 (PDT)
Received: from [192.168.168.243] (p4FE59DFB.dip0.t-ipconnect.de [79.229.157.251]) (authenticated bits=0) by lo.psyced.org (8.14.3/8.14.3/Debian-9.4) with ESMTP id r7E6sNv7020589 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for <mmusic@ietf.org>; Wed, 14 Aug 2013 08:54:30 +0200
Message-ID: <520B299F.9060409@goodadvice.pages.de>
Date: Wed, 14 Aug 2013 08:54:23 +0200
From: Philipp Hancke <fippo@goodadvice.pages.de>
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130623 Thunderbird/17.0.7
MIME-Version: 1.0
To: mmusic@ietf.org
Content-Type: text/plain; charset="ISO-8859-15"; format="flowed"
Content-Transfer-Encoding: 7bit
Subject: [MMUSIC] RFC 5245: ice-ufrags of length 256 vs stun maximum username length of 512 bytes
X-BeenThere: mmusic@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: Multiparty Multimedia Session Control Working Group <mmusic.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/mmusic>, <mailto:mmusic-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/mmusic>
List-Post: <mailto:mmusic@ietf.org>
List-Help: <mailto:mmusic-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/mmusic>, <mailto:mmusic-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 14 Aug 2013 06:54:47 -0000

It seems that there is a minor inconsistency between the maximum 
username length in STUN and the way ice-ufrag is defined...

5245 allows ufrags of up to 256 characters:
	-- http://tools.ietf.org/html/rfc5245#section-15.4

The STUN username is formed as RFRAG:LFRAG
	http://tools.ietf.org/html/rfc5245#section-7.1.2.3

If both sides use 256 characters for their ufrags this would result in a 
513 byte STUN username. However, 5389 says the username has to be "less 
than 513 bytes".
	-- http://tools.ietf.org/html/rfc5389#section-15.3

Off by one?

For ice-pwd this isn't a problem, right?

v2.23.0 | Report a Bug | By Email