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.
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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