[kitten] [Technical Errata Reported] RFC6616 (7074)

RFC Errata System <rfc-editor@rfc-editor.org> Sat, 06 August 2022 13:26 UTC

To: lear@cisco.com, Hannes.Tschofenig@gmx.net, hmauldin@cisco.com, simon@josefsson.org, rdd@cert.org, paul.wouters@aiven.io, alexey.melnikov@isode.com
From: RFC Errata System <rfc-editor@rfc-editor.org>
Cc: me@dequbed.space, kitten@ietf.org, rfc-editor@rfc-editor.org
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Message-Id: <20220806132612.AFB8C119FC@rfcpa.amsl.com>
Date: Sat, 06 Aug 2022 06:26:12 -0700
Archived-At: <https://mailarchive.ietf.org/arch/msg/kitten/L2lIp8RybULsKZXWxS7uKXELHj8>
Subject: [kitten] [Technical Errata Reported] RFC6616 (7074)
Precedence: list

The following errata report has been submitted for RFC6616,
"A Simple Authentication and Security Layer (SASL) and Generic Security Service Application Program Interface (GSS-API) Mechanism for OpenID".

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You may review the report below and at:
https://www.rfc-editor.org/errata/eid7074

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Type: Technical
Reported by: Nadja Reitzenstein <me@dequbed.space>

Section: 2.1

Original Text
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The nonce value MUST be at least 2^32 bits and large enough to
handle well in excess of the number of concurrent transactions
a SASL server shall see.

Corrected Text
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The nonce value MUST be at least 32 bits and large enough to
handle well in excess of the number of concurrent transactions
a SASL server shall see.

Notes
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A nonce of 512MiB is rather excessive to be generated for every authenticating client.

As this nonce also has to be transported within the URI sent to both the SASL client and called by the OIDC IdP the Note in section 3.2.1 of RFC 2616 seems to apply:
"Servers ought to be cautious about depending on URI lengths above 255 bytes, because some older client or proxy implementations might not properly support these lengths."

A lower bound requirement of 32 bits for the nonce seems more appropiate; most platforms are able to efficiently handle 32-bit integers and is still likely to prevent a brute-force attack given the HTTP request overhead.

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RFC6616 (draft-ietf-kitten-sasl-openid-08)
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Title : A Simple Authentication and Security Layer (SASL) and Generic Security Service Application Program Interface (GSS-API) Mechanism for OpenID
Publication Date : May 2012
Author(s) : E. Lear, H. Tschofenig, H. Mauldin, S. Josefsson
Category : PROPOSED STANDARD
Source : Common Authentication Technology Next Generation
Area : Security
Stream : IETF
Verifying Party : IESG

[kitten] [Technical Errata Reported] RFC6616 (707… RFC Errata System
Re: [kitten] [Technical Errata Reported] RFC6616 … Simon Josefsson