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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.

   Internet-Drafts are working documents of the Internet Engineering
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on October 1, 2017.

Copyright Notice

   Copyright (c) 2017 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
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.



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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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