SSH IANA registry policy: Update to the IANA SSH Protocol Parameters Registry Requirements
SSH's IANA registries move from needing an RFC to needing a quick sign-off from designated experts.
Yee, P., "Update to the IANA SSH Protocol Parameters Registry Requirements", RFC 9519, DOI 10.17487/RFC9519, January 2024, <https://www.rfc-editor.org/info/rfc9519>.
@misc{rfc9519,
series = {Request for Comments},
number = 9519,
howpublished = {RFC 9519},
publisher = {RFC Editor},
doi = {10.17487/RFC9519},
url = {https://www.rfc-editor.org/info/rfc9519},
author = {P. Yee},
title = {{Update to the IANA SSH Protocol Parameters Registry Requirements}},
pagetotal = 6,
year = 2024,
month = jan,
} RFC text
Contents
Internet Engineering Task Force (IETF) P. Yee
Request for Comments: 9519 AKAYLA
Updates: 4250, 4716, 4819, 8308 January 2024
Category: Standards Track
ISSN: 2070-1721
Update to the IANA SSH Protocol Parameters Registry Requirements
Abstract
This specification updates the registration policies for adding new
entries to registries within the IANA "Secure Shell (SSH) Protocol
Parameters" group of registries. Previously, the registration policy
was generally IETF Review, as defined in RFC 8126, although a few
registries require Standards Action. This specification changes it
from IETF Review to Expert Review. This document updates RFCs 4250,
4716, 4819, and 8308.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9519.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Revised BSD License text as described in Section 4.e of the
Trust Legal Provisions and are provided without warranty as described
in the Revised BSD License.
Table of Contents
1. Introduction
1.1. Requirements Language
2. SSH Protocol Parameters Affected
3. Designated Expert Pool
4. IANA Considerations
5. Security Considerations
6. References
6.1. Normative References
6.2. Informative References
Acknowledgements
Author's Address
1. Introduction
The IANA "Secure Shell (SSH) Protocol Parameters" registry was
populated by several RFCs including [RFC4250], [RFC4716], [RFC4819],
and [RFC8308]. Outside of some narrow value ranges that require
Standards Action in order to add new values or that are marked for
Private Use, the registration policy for other portions of the
registry was IETF Review [RFC8126]. This specification changes the
policy from IETF Review to Expert Review. This change is in line
with similar changes undertaken for certain IPsec and TLS registries.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
2. SSH Protocol Parameters Affected
The following table lists the "Secure Shell (SSH) Protocol
Parameters" registries whose registration policy has changed from
IETF Review to Expert Review. Where this change applied to a
specific range of values within the particular parameter, that range
is given in the notes column. Affected registries now list this
document as a reference.
+===============================+===========+=======================+
| Parameter Name | RFC | Notes |
+===============================+===========+=======================+
| Authentication Method | [RFC4250] | |
| Names | | |
+-------------------------------+-----------+-----------------------+
| Channel Connection | [RFC4250] | 0x00000001-0xFDFFFFFF |
| Failure Reason Codes | | (inclusive) |
| and Descriptions | | |
+-------------------------------+-----------+-----------------------+
| Compression Algorithm | [RFC4250] | |
| Names | | |
+-------------------------------+-----------+-----------------------+
| Connection Protocol | [RFC4250] | |
| Channel Request Names | | |
+-------------------------------+-----------+-----------------------+
| Connection Protocol | [RFC4250] | |
| Channel Types | | |
+-------------------------------+-----------+-----------------------+
| Connection Protocol | [RFC4250] | |
| Global Request Names | | |
+-------------------------------+-----------+-----------------------+
| Connection Protocol | [RFC4250] | |
| Subsystem Names | | |
+-------------------------------+-----------+-----------------------+
| Disconnection Messages | [RFC4250] | 0x00000001-0xFDFFFFFF |
| Reason Codes and | | (inclusive) |
| Descriptions | | |
+-------------------------------+-----------+-----------------------+
| Encryption Algorithm | [RFC4250] | |
| Names | | |
+-------------------------------+-----------+-----------------------+
| Extended Channel Data | [RFC4250] | 0x00000001-0xFDFFFFFF |
| Transfer data_type_code | | (inclusive) |
| and Data | | |
+-------------------------------+-----------+-----------------------+
| Extension Names | [RFC8308] | |
+-------------------------------+-----------+-----------------------+
| Key Exchange Method | [RFC4250] | |
| Names | | |
+-------------------------------+-----------+-----------------------+
| MAC Algorithm Names | [RFC4250] | |
+-------------------------------+-----------+-----------------------+
| Pseudo-Terminal Encoded | [RFC4250] | |
| Terminal Modes | | |
+-------------------------------+-----------+-----------------------+
| Public Key Algorithm | [RFC4250] | |
| Names | | |
+-------------------------------+-----------+-----------------------+
| Publickey Subsystem | [RFC4819] | |
| Attributes | | |
+-------------------------------+-----------+-----------------------+
| Publickey Subsystem | [RFC4819] | |
| Request Names | | |
+-------------------------------+-----------+-----------------------+
| Publickey Subsystem | [RFC4819] | |
| Response Names | | |
+-------------------------------+-----------+-----------------------+
| Service Names | [RFC4250] | |
+-------------------------------+-----------+-----------------------+
| Signal Names | [RFC4250] | |
+-------------------------------+-----------+-----------------------+
| SSH Public-Key File | [RFC4716] | Excluding header-tags |
| Header Tags | | beginning with x- |
+-------------------------------+-----------+-----------------------+
Table 1: Secure Shell (SSH) Protocol Parameters Affected
The only IANA SSH protocol parameter registries not affected are
"Message Numbers" and "Publickey Subsystem Status Codes", as these
remain Standards Action due to their limited resources as one-byte
registry values.
3. Designated Expert Pool
Expert Review [RFC8126] registry requests are registered after a
three-week review period on the <ssh-reg-review@ietf.org> mailing
list, and on the advice of one or more designated experts. However,
to allow for the allocation of values prior to publication, the
designated experts may approve registration once they are satisfied
that such a specification will be published.
Registration requests sent to the mailing list for review SHOULD use
an appropriate subject (e.g., "Request to register value in SSH
protocol parameters <specific parameter> registry").
Within the review period, the designated experts will either approve
or deny the registration request, communicating this decision to the
review list and IANA. Denials MUST include an explanation and, if
applicable, suggestions as to how to make the request successful.
Registration requests that are undetermined for a period longer than
21 days can be brought to the IESG's attention (using the
<iesg@ietf.org> mailing list) for resolution.
Criteria that SHOULD be applied by the designated experts includes
determining whether the proposed registration duplicates existing
functionality (which is not permitted), whether it is likely to be of
general applicability or useful only for a single application, and
whether the registration description is clear.
IANA MUST only accept registry updates from the designated experts
and the IESG. It SHOULD direct all requests for registration from
other sources to the review mailing list.
It is suggested that multiple designated experts be appointed who are
able to represent the perspectives of different applications using
this specification, in order to enable broadly informed review of
registration decisions. In cases where a registration decision could
be perceived as creating a conflict of interest for a particular
expert, that expert SHOULD defer to the judgment of the other
experts.
4. IANA Considerations
This memo is entirely about updating the IANA "Secure Shell (SSH)
Protocol Parameters" registry.
5. Security Considerations
This memo does not change the Security Considerations for any of the
updated RFCs.
6. References
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC4250] Lehtinen, S. and C. Lonvick, Ed., "The Secure Shell (SSH)
Protocol Assigned Numbers", RFC 4250,
DOI 10.17487/RFC4250, January 2006,
<https://www.rfc-editor.org/info/rfc4250>.
[RFC4819] Galbraith, J., Van Dyke, J., and J. Bright, "Secure Shell
Public Key Subsystem", RFC 4819, DOI 10.17487/RFC4819,
March 2007, <https://www.rfc-editor.org/info/rfc4819>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8308] Bider, D., "Extension Negotiation in the Secure Shell
(SSH) Protocol", RFC 8308, DOI 10.17487/RFC8308, March
2018, <https://www.rfc-editor.org/info/rfc8308>.
6.2. Informative References
[CURDLE-MA]
Turner, S., "Subject: [Curdle] Time to Review IANA SSH
Registries Policies?", message to the Curdle mailing list,
February 2021,
<https://mailarchive.ietf.org/arch/msg/curdle/
gdiOlZr9bnrZv8umVyguGG3woIM/>.
[RFC4716] Galbraith, J. and R. Thayer, "The Secure Shell (SSH)
Public Key File Format", RFC 4716, DOI 10.17487/RFC4716,
November 2006, <https://www.rfc-editor.org/info/rfc4716>.
Acknowledgements
The impetus for this specification was a February 2021 discussion on
the CURDLE mailing list [CURDLE-MA].
Author's Address
Peter E. Yee
AKAYLA
Mountain View, CA 94043
United States of America
Email: peter@akayla.com
AI ELI5
On this page
§1Why the Policy Changed
The IANA Secure Shell (SSH) Protocol Parameters registry group was populated by several RFCs, including RFC 4250, RFC 4716, RFC 4819 and RFC 8308. Apart from some narrow value ranges that need Standards Action or are marked Private Use, new entries required IETF Review, as defined in RFC 8126.
This document changes that policy to Expert Review. The RFC says the change is in line with similar changes made for certain IPsec and TLS registries. The impetus was a February 2021 discussion on the CURDLE mailing list.
Getting a new item on the SSH list used to be a long process. The rule was changed so it is faster, like the lists other groups already made easier.
§2Which Registries Are Affected
Table 1 of the RFC lists the registries that move from IETF Review to Expert Review. They include the names registries for authentication methods, compression algorithms, encryption algorithms, key exchange methods, MAC algorithms and public key algorithms, plus connection protocol channel types, request names and subsystem names, service names, signal names, extension names and the publickey subsystem registries.
Some entries apply only to part of a registry. For three registries (channel connection failure reason codes, disconnection reason codes, and extended channel data transfer data_type_code), only the range 0x00000001-0xFDFFFFFF changes. For SSH public-key file header tags, header tags beginning with x- are excluded. Affected registries now list this document as a reference.
Two registries are not affected: Message Numbers and Publickey Subsystem Status Codes. They stay at Standards Action because their one-byte values are a limited resource.
Almost every SSH list gets the easier rule. Two small lists with very few slots stay strict, because there are so few spaces to give out.
| Registries | Policy now |
|---|---|
| Most SSH parameter registries (Table 1) THIS RFC | Expert Review (was IETF Review) |
| Message Numbers | Standards Action |
| Publickey Subsystem Status Codes | Standards Action |
§3How Expert Review Works
A registration request is sent to the ssh-reg-review@ietf.org mailing list. It is registered after a three-week review period, on the advice of one or more designated experts. Requests SHOULD use an appropriate subject, for example "Request to register value in SSH protocol parameters <specific parameter> registry".
Within the review period the experts approve or deny the request and tell the review list and IANA. A denial MUST include an explanation and, where applicable, suggestions for making the request succeed. To allow values to be allocated before publication, the experts may approve a registration once they are satisfied that a specification will be published.
A request that stays undetermined for longer than 21 days can be brought to the IESG's attention using the iesg@ietf.org mailing list.
You post your idea where everyone can see it. After three weeks, the helpers say yes or no, and if it is no they must say why and how to fix it.
§4The Experts and Their Criteria
The experts SHOULD check whether the proposed registration duplicates existing functionality (which is not permitted), whether it is likely to be of general applicability or useful only for a single application, and whether the registration description is clear.
IANA MUST only accept registry updates from the designated experts and the IESG, and SHOULD send requests from any other source to the review mailing list.
The RFC suggests appointing several experts who can represent the perspectives of different applications using SSH. If a decision could look like a conflict of interest for one expert, that expert SHOULD defer to the others.
The helpers ask: is this the same as something we already have, will many people use it, and is it explained clearly? If a helper has a personal stake, they step back and let the others decide.
§5Security and IANA Considerations
The IANA Considerations section says that the memo is entirely about updating the IANA Secure Shell (SSH) Protocol Parameters registry. The Security Considerations section is equally short: the memo does not change the Security Considerations of any of the updated RFCs.
This change is only about the paperwork for adding things to a list. It does not change how safe SSH is.