IETF Logo Mail Archive

Re: [Cbor] Chunks with tags inside indefinite-length string (major type 2 and 3)

worley@ariadne.com (Dale R. Worley) Tue, 10 December 2019 01:46 UTC

Return-Path: <worley@alum.mit.edu>
X-Original-To: cbor@ietfa.amsl.com
Delivered-To: cbor@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 6894712002F for <cbor@ietfa.amsl.com>; Mon, 9 Dec 2019 17:46:48 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.684
X-Spam-Level:
X-Spam-Status: No, score=-1.684 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, HEADER_FROM_DIFFERENT_DOMAINS=0.25, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_SOFTFAIL=0.665] autolearn=no autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=comcastmailservice.net
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id mJAReKVbMXgo for <cbor@ietfa.amsl.com>; Mon, 9 Dec 2019 17:46:47 -0800 (PST)
Received: from resqmta-ch2-08v.sys.comcast.net (resqmta-ch2-08v.sys.comcast.net [IPv6:2001:558:fe21:29:69:252:207:40]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id F016312001A for <cbor@ietf.org>; Mon, 9 Dec 2019 17:46:46 -0800 (PST)
Received: from resomta-ch2-17v.sys.comcast.net ([69.252.207.113]) by resqmta-ch2-08v.sys.comcast.net with ESMTP id eTWcika9y7jwaeUbtir3Dj; Tue, 10 Dec 2019 01:46:45 +0000
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcastmailservice.net; s=20180828_2048; t=1575942405; bh=MNKgLUeDXFisf3vGwVVS1NGb3ymn3d/9SQowqdtLgvQ=; h=Received:Received:Received:Received:From:To:Subject:Date: Message-ID; b=dhSgFQb81tUqXb+4rWxfVJZjWVNmr7kLja4F3HiU5Rw8m03B7WL6LKsQJM0grxp1j NuUHXFceuZmQF9k+klpqHwflVb0xPNUp0VXmajh2CY10mheoAAKrhvRmgBPX7osQ+e j/OFcRKj8NvAIcSqSmYSj2eFnUE7ayZzTW+P9p26kNbXr3emULl0DI78wMy98uhPKU juaGARqUQdoAXRDnbZqz7N3uT36BxpTdYJzIan2gWOlGshjGHhaZ3hOf441HYsMPhG zXT8Sd5RCj5W90nE7svoKULLY1rH0TtNx+TBrnidcOIE2P5VBSurRb2ys339Pb565t KdyAKoTtM+gww==
Received: from hobgoblin.ariadne.com ([IPv6:2601:192:4600:1e00:222:fbff:fe91:d396]) by resomta-ch2-17v.sys.comcast.net with ESMTPA id eUbsiASzeoG7SeUbtia8BR; Tue, 10 Dec 2019 01:46:45 +0000
X-Xfinity-VMeta: sc=0.00;st=legit
Received: from hobgoblin.ariadne.com (hobgoblin.ariadne.com [127.0.0.1]) by hobgoblin.ariadne.com (8.14.7/8.14.7) with ESMTP id xBA1khIt017827; Mon, 9 Dec 2019 20:46:43 -0500
Received: (from worley@localhost) by hobgoblin.ariadne.com (8.14.7/8.14.7/Submit) id xBA1kgxb017824; Mon, 9 Dec 2019 20:46:42 -0500
X-Authentication-Warning: hobgoblin.ariadne.com: worley set sender to worley@alum.mit.edu using -f
From: worley@ariadne.com
To: Faye Amacker <faye.github@gmail.com>
Cc: cbor@ietf.org
In-Reply-To: <CA+qCGhv_d=uJxnPrnbRO_iN9nVhwPf0Qa8EvtqqXZS6pMaCyBw@mail.gmail.com> (faye.github@gmail.com)
Sender: worley@ariadne.com
Date: Mon, 09 Dec 2019 20:46:42 -0500
Message-ID: <87a78154vx.fsf@hobgoblin.ariadne.com>
Archived-At: <https://mailarchive.ietf.org/arch/msg/cbor/xC9BpSdE5gKNJXAn6xzhfnZRGzE>
Subject: Re: [Cbor] Chunks with tags inside indefinite-length string (major type 2 and 3)
X-BeenThere: cbor@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "Concise Binary Object Representation \(CBOR\)" <cbor.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/cbor>, <mailto:cbor-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/cbor/>
List-Post: <mailto:cbor@ietf.org>
List-Help: <mailto:cbor-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/cbor>, <mailto:cbor-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 10 Dec 2019 01:46:49 -0000

Faye Amacker <faye.github@gmail.com> writes:
> And the pseudocode in Appendix C allows tags for chunks inside
> indefinite-length strings.

It seems to me that the safe option, the one that will cause the least
trouble in the future, is to define tags on items inside
indefinite-length structure as syntactically well-structured but
semantically having no defined meaning.  Actually, that's the same as we
treat use of tags whose values haven't been defined.

Functionally, that means that no current application should generate
them (and thus an application for the same universe of values should
expect to never see them), but "generic" decoders should be prepared to
see such tags.

Dale

v2.23.0 | Report a Bug | By Email