IETF Logo Mail Archive

Re: [Cbor] Invalid Tag Values

Laurence Lundblade <lgl@island-resort.com> Thu, 24 June 2021 19:20 UTC

Return-Path: <lgl@island-resort.com>
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 738C23A2826 for <cbor@ietfa.amsl.com>; Thu, 24 Jun 2021 12:20:13 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.896
X-Spam-Level:
X-Spam-Status: No, score=-1.896 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HTML_MESSAGE=0.001, SPF_HELO_NONE=0.001, SPF_NONE=0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
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 QESkJ9sSP7NU for <cbor@ietfa.amsl.com>; Thu, 24 Jun 2021 12:20:09 -0700 (PDT)
Received: from p3plsmtpa11-04.prod.phx3.secureserver.net (p3plsmtpa11-04.prod.phx3.secureserver.net [68.178.252.105]) (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 EC4BC3A2825 for <cbor@ietf.org>; Thu, 24 Jun 2021 12:20:08 -0700 (PDT)
Received: from [192.168.4.71] ([135.180.5.239]) by :SMTPAUTH: with ESMTPSA id wUtPlNszVj4HewUtRlQq9p; Thu, 24 Jun 2021 12:20:06 -0700
X-CMAE-Analysis: v=2.4 cv=PaU6Ogtd c=1 sm=1 tr=0 ts=60d4dae7 a=yGLcT55IBd5ZT4hal3HKuA==:117 a=yGLcT55IBd5ZT4hal3HKuA==:17 a=4tOVxll6AAAA:8 a=48vgC7mUAAAA:8 a=1X73dAa4AAAA:20 a=oTo3nEFKwZy6Ob3OXkwA:9 a=QEXdDO2ut3YA:10 a=IoWA_yT2SMIA:10 a=TmGiPmaXGoYA:10 a=uYFAVk8h1b417Kfh2jQA:9 a=FocE5EpSTM52Rh3H:21 a=_W_S_7VecoQA:10 a=DYY0s9dCeKRJPMT8920N:22 a=w1C3t2QeGrPiZgrLijVG:22
X-SECURESERVER-ACCT: lgl@island-resort.com
From: Laurence Lundblade <lgl@island-resort.com>
Message-Id: <D2CE71A4-5845-4040-8FF8-549006FC8C50@island-resort.com>
Content-Type: multipart/alternative; boundary="Apple-Mail=_14D507A5-B78D-4585-ACA3-7E8FA90995DE"
Mime-Version: 1.0 (Mac OS X Mail 13.4 \(3608.120.23.2.1\))
Date: Thu, 24 Jun 2021 12:20:03 -0700
In-Reply-To: <f5650d87a36b10f6b75d2a1123f84bb5@mothers-arms.co.uk>
Cc: cbor@ietf.org
To: Kio Smallwood <kio@mothers-arms.co.uk>
References: <f5650d87a36b10f6b75d2a1123f84bb5@mothers-arms.co.uk>
X-Mailer: Apple Mail (2.3608.120.23.2.1)
X-CMAE-Envelope: MS4xfLh1tU0qbIJ29RPbIM1VqSYauVgXwCGSTG59JyeWOEXGQB5ez7gkfzYUCv7vGS3e11nHYuL8+pH0FOWcaCsaMhT+Aws78nmOmr9x39vn45Mtif8ePHO8 Q9q5bsCkwea4ZFryDMJS/qeFYQg/C2bzwcem3b0ALuUz2rrhGB/JRNSfJ/Fe/sdi4kJQ9C7Lj4O7EEJIt+6Rbvr6jm93XZ1wQmlAPlkonXDadmxxpk4/orMo
Archived-At: <https://mailarchive.ietf.org/arch/msg/cbor/9op0zyYSDtZmZ1x1mdmHnSEtKDU>
Subject: Re: [Cbor] Invalid Tag Values
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: Thu, 24 Jun 2021 19:20:13 -0000

My understanding and use of them is this — they are never put in encoded CBOR and they are useful *inside* a decoder to have an out-of-band value tag like a NULL pointer.

LL
 

> On Jun 24, 2021, at 12:15 PM, Kio Smallwood <kio@mothers-arms.co.uk> wrote:
> 
> Hi All,
> 
> I'm having trouble understanding the rationale of intentionally invalid tags as documented here[1]
> 
> Under what circumstances would an encoder produce these tags and what should a decoder do when encountering them? Since I'm working on that part of the decoder[2] anyway I thought I'd better check.
> 
> Thanks,
> 
> Kio
> 
> [1] https://www.ietf.org/archive/id/draft-bormann-cbor-notable-tags-03.html#section-toc.1-1.10.2.1.1 <https://www.ietf.org/archive/id/draft-bormann-cbor-notable-tags-03.html#section-toc.1-1.10.2.1.1>
> [2] https://github.com/agronholm/cbor2/pull/115 <https://github.com/agronholm/cbor2/pull/115>_______________________________________________
> CBOR mailing list
> CBOR@ietf.org
> https://www.ietf.org/mailman/listinfo/cbor

v2.23.0 | Report a Bug | By Email