Internet DRAFT - draft-ietf-kitten-kerberos-iana-registries
draft-ietf-kitten-kerberos-iana-registries
Network Working Group T. Yu
Internet-Draft MIT Kerberos Consortium
Updates: rfc4120 (if approved) March 30, 2017
Intended status: Standards Track
Expires: October 1, 2017
Move Kerberos protocol parameter registries to IANA
draft-ietf-kitten-kerberos-iana-registries-04
Abstract
The Keberos 5 network authentication protocol has several numeric
protocol parameters. Most of these parameters are not currently
under IANA maintenance. This document requests that IANA take over
the maintenance of the remainder of these Kerberos parameters.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on October 1, 2017.
Copyright Notice
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document authors. All rights reserved.
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1. Requirements Notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
2. Introduction
The Keberos 5 network authentication protocol[RFC4120][RFC1510] has
several numeric protocol parameters. This document requests that
IANA take over the maintenance of the Kerberos protocol parameters
that are not currently under IANA maintenance. Several instances of
number conflicts in Kerberos implementations could have been
prevented by having IANA registries for those numbers. This document
updates [RFC4120].
3. General registry format
Unless otherwise specified, each Kerberos protocol number registry
will have the following fields: "number", "name", "reference", and
"comments".
The name must begin with a lowercase letter, and must consist of
ASCII letters, digits, and hyphens. Two or more hyphens must not
appear directly adjacent to each other. A hyphen must not appear at
the end of a name. It is preferred that words in a name be separated
by hyphens, and that all of the letters be lowercase.
(These rules are consistent with the lexical rules for an ASN.1
valuereference or identifier. Where the constraints are stricter
than the ASN.1 lexical rules, they make it easier to systematically
transform the names for use in implementation languages.)
Names for numeric parameter values have no inherent meaning in the
Kerberos protocol, but they can guide choices for internal
implementation symbol names and for user-visible non-numeric
representations. When written in English prose in specifications, or
when used as symbolic constants in implementation languages (e.g., C
preprocessor macros), it is common to transform the name into all
uppercase letters, and possibly to replace hyphens with underscores.
4. General registration procedure
This document requests that the IESG establish a pool of Kerberos
experts who will manage the Kerberos registries using these
guidelines. The IESG may wish to consider including the set of
designated IANA experts for existing Kerberos IANA registries as
candidates for this pool.
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IANA will select an expert from this pool for each registration
request. The expert will review the registration request and may
approve the registration, decline the registration with comments, or
recommend that the registration request should follow a specific
alternative process. The alternative processes that the expert may
recommend are the IETF review process and the standards action
process.
Initially, the expert reviewers will use a permissive process,
generally approving registrations that are architecturally consistent
with Kerberos and the protocol parameter in question. Over time,
with input from the community, the experts may refine the
requirements that registrations are expected to meet. The experts
will maintain a current version of these guidelines in a manner that
is generally accessible to the entire community. As the guidelines
evolve, experts may consider the technical quality of specifications,
security impacts of the registrations, architectural consistency, and
interoperability impact. Experts may require a publicly available
specification in order to make certain registrations.
[ For the individual registries, include "Registrations in this
registry are managed by the expert review process [RFC5226] or in
exceptional cases by IESG approval. See section x for guidelines for
the experts to be used with this registry." ]
5. Integer assignments
Names for integer assignments must be unique across all Kerberos
integer parameter registries. This is normally accomplished by
including a name prefix that identifies the registry.
Assignments for integers parameters will follow the general
registration procedure outlined above, except as otherwise noted in
the section that contains the description of the parameter. Kerberos
integer parameters take on signed 32-bit values (-2147483648 to
2147483647). Negative values are for private or local use.
5.1. Address types
Registry name: Address types
Assignment policy: General registration procedure
Valid values: Signed 32-bit integers
Address types historically align with numeric constants used in the
Berkeley sockets API. Future address type assignments should conform
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to this historical practice when possible. The name prefix for
address types is "addrtype-".
5.2. Authorization data types
Registry name: Authorization data types
Assignment policy: General registration procedure
Valid values: Signed 32-bit integers
The name prefix for authorization data types is "ad-".
5.3. Error codes
Registry name: Error codes
Assignment policy: Standards action
Valid values: Signed 32-bit integers
Assignments for error codes require standards action due to their
scarcity: assigning error codes greater than 127 could require
significant changes to certain implementations. The name prefixes
for error codes are "kdc-err-", "krb-err-", and "krb-ap-err-".
5.4. Key usages
Registry name: Key usages
Assignment policy: General registration procedure
Valid values: Unsigned 32-bit integers
Key usages are unsigned 32-bit integers (0 to 4294967295). Zero is
reserved and may not be assigned.
The name prefix for key usages is "ku-".
5.5. Name types
Registry name: Name types
Assignment policy: General registration procedure
Valid values: Signed 32-bit integers
The name prefix for name types is "nt-".
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+--------+-------------------+-----------+--------------------------+
| number | name | reference | comment |
+--------+-------------------+-----------+--------------------------+
| 0 | nt-unknown | RFC4120 | Name type not known |
| 1 | nt-principal | RFC4120 | Just the name of the |
| | | | principal as in DCE, or |
| | | | for users |
| 2 | nt-srv-inst | RFC4120 | Service and other unique |
| | | | instance (krbtgt) |
| 3 | nt-srv-hst | RFC4120 | Service with host name |
| | | | as instance (telnet, |
| | | | rcommands) |
| 4 | nt-srv-xhst | RFC4120 | Service with host as |
| | | | remaining components |
| 5 | nt-uid | RFC4120 | Unique ID |
| 6 | nt-x500-principal | RFC4120 | Encoded X.509 |
| | | | Distinguished name |
| | | | [RFC2253] |
| 7 | nt-smtp-name | RFC4120 | Name in form of SMTP |
| | | | email name (e.g., |
| | | | user@example.com) |
| 10 | nt-enterprise | RFC4120 | Enterprise name - may be |
| | | | mapped to principal name |
| 11 | nt-wellknown | RFC6111 | Well-known principal |
| | | | name |
| 12 | nt-srv-hst-domain | RFC5179 | Domain-based names |
+--------+-------------------+-----------+--------------------------+
5.6. Pre-authentication and typed data
Registry name: Pre-authentication and typed data
Assignment policy: General registration procedure
Valid values: Signed 32-bit integers
This document requests that IANA modify the existing Kerberos Pre-
authentication and typed data registry to be consistent with the
procedures in this document.
The name prefix for pre-authentication type numbers is "pa-". The
name prefix for typed data numbers is "td-". Pre-authentication and
typed data numbers are in the same registry, but a pre-authentication
number may be also be assigned to a related typed data number.
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6. Named bit assignments
Assignments for named bits require standards action, due to their
scarcity: assigning bit numbers greater than 31 could require
significant changes to implementations. Names for named bit
assignments must be unique within a given named bit registry, and
typically do not have name prefixes that identify which registry they
belong to.
6.1. AP-REQ options
Registry name: AP-REQ options
Assignment policy: Standards action
Valid values: ASN.1 bit numbers 0 through 31
6.2. KDC-REQ options
Registry name: KDC-REQ options
Assignment policy: Standards action
Valid values: ASN.1 bit numbers 0 through 31
6.3. Ticket flags
Registry name: Ticket flags
Assignment policy: Standards action
Valid values: ASN.1 bit numbers 0 through 31
7. Numbers that will not be registered
ASN.1 application tag numbers (which are always equal to the "msg-
type" field in Kerberos messages where they appear) will not be
registered. Any Kerberos protocol change that requires a new
application tag number will be a sufficiently major change that the
specification of the change MUST define a new ASN.1 module and MUST
be Standards Track.
Transited encoding values will not be registered. There is only one
transited encoding type for the Kerberos protocol. The
interoperability concerns inherent to the cross-realm operation of
Kerberos mean that specifications of new transited encoding types are
very unlikely. Any specification of new transited encoding types
MUST be Standards Action.
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Protocol version number (pvno) values will not be registered. The
location of the "pvno" value in Kerberos messages is not in a place
that implementations can meaningfully use to distinguish among
different variants of the Kerberos protocol.
8. Contributors
Sam Hartman proposed the text of the expert review guidelines. Love
Hornquist Astrand wrote a previous document (draft-lha-krb-wg-some-
numbers-to-iana-00) with the same goals as this document.
9. Acknowledgments
Thanks to Tom Petch for providing useful feedback on previous
versions of this document.
10. Security Considerations
Assignments of new Keberos protocol parameter values can have
security implications. In cases where the assignment policy calls
for expert review, the reviewer is responsible for evaluating whether
adequate documentation exists concerning the security considerations
for the requested assignment. For assignments that require IETF
review or standards action, the normal IETF processes ensure adequate
treatment of security considerations.
11. IANA Considerations
This document requests that IANA create several registries for
Kebreros protocol parameters:
o Address types
o Authorization data types
o Error codes
o Key usages
o Name types
o AP-REQ options
o KDC-REQ options
o Ticket flags
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This document requests that IANA modify the existing "Pre-
authentication data and typed data" registry to contain an additional
reference to this document, and to transform existing names in that
registry to the lowercase-and-hyphens style.
12. Open issues
Do we make a registry for application tag numbers (equal to message
type numbers)? We've said that we would replace the entire ASN.1
module in that case, but Nico's recent proposal doesn't do that, and
if we want to accommodate that sort of proposal, it would probably be
best to establish a registry. (It should require standards action
for registrations.)
Do transited encodings need a registry? They would probably require
standards action, even if there were a registry.
13. References
13.1. 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,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC3961] Raeburn, K., "Encryption and Checksum Specifications for
Kerberos 5", RFC 3961, DOI 10.17487/RFC3961, February
2005, <http://www.rfc-editor.org/info/rfc3961>.
[RFC4120] Neuman, C., Yu, T., Hartman, S., and K. Raeburn, "The
Kerberos Network Authentication Service (V5)", RFC 4120,
DOI 10.17487/RFC4120, July 2005,
<http://www.rfc-editor.org/info/rfc4120>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>.
13.2. Informative References
[RFC1510] Kohl, J. and C. Neuman, "The Kerberos Network
Authentication Service (V5)", RFC 1510,
DOI 10.17487/RFC1510, September 1993,
<http://www.rfc-editor.org/info/rfc1510>.
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Author's Address
Tom Yu
MIT Kerberos Consortium
77 Massachusetts Ave
Cambridge, Massachusetts
USA
Email: tlyu@mit.edu
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