Network Working Group                                        N. Williams
Request for Comments: 5179                                           Sun
Category: Standards Track                                       May 2008


   Generic Security Service Application Program Interface (GSS-API)
 Domain-Based Service Names Mapping for the Kerberos V GSS Mechanism

Status of This Memo

  This document specifies an Internet standards track protocol for the
  Internet community, and requests discussion and suggestions for
  improvements.  Please refer to the current edition of the "Internet
  Official Protocol Standards" (STD 1) for the standardization state
  and status of this protocol.  Distribution of this memo is unlimited.

Abstract

  This document describes the mapping of Generic Security Service
  Application Program Interface (GSS-API) domain-name-based service
  principal names onto Kerberos V principal names.

Table of Contents

  1.  Domain-Based Names for the Kerberos V GSS-API Mechanism . . . . 2
  2.  Conventions Used in This Document . . . . . . . . . . . . . . . 2
  3.  Internationalization Considerations . . . . . . . . . . . . . . 2
  4.  Examples  . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
  5.  Security Considerations . . . . . . . . . . . . . . . . . . . . 3
  6.  Normative References  . . . . . . . . . . . . . . . . . . . . . 3





















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1.  Domain-Based Names for the Kerberos V GSS-API Mechanism

  In accordance with [RFC5178], this document provides the mechanism-
  specific details needed to implement GSS-API [RFC2743] domain-based
  service names with the Kerberos V GSS-API mechanism [RFC4121].

  GSS_C_NT_DOMAINBASED_SERVICE name SHOULD be mapped to Kerberos V
  principal names as follows:

  o  the <service> name becomes the first (0th) component of the
     Kerberos V principal name;

  o  the <hostname> becomes the second component of the Kerberos V
     principal name;

  o  the <domain> name becomes the third component of the Kerberos V
     principal name;

  o  the realm of the resulting principal name is that which
     corresponds to the domain name, treated as a hostname.

  The same name canonicalization considerations and methods as used
  elsewhere in the Kerberos V GSS-API mechanism [RFC4121] and Kerberos
  V [RFC4120] in general apply here.

  Implementations SHOULD use a Kerberos V name-type of
  NTT-SRVT-HST-DOMAIN (which has the value 12) but MAY use NT-UNKNOWN
  instead.

2.  Conventions Used in This Document

  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].

3.  Internationalization Considerations

  It is unclear, at this time, how best to address internationalization
  of Kerberos V domain-based principal names.  This is because the
  Kerberos V core protocol internationalization project is incomplete.

  However, clearly the best way to interoperate when using Kerberos V
  domain-based principal names is to use ACE-encoded internationalized
  domain names [RFC3490] for the hostname and domain name slots of a
  Kerberos V domain-based principal name.  Therefore Kerberos V GSS-API
  mechanism implementations MUST do just that.





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4.  Examples

  o  The domain-based name, of generic form,
     "[email protected]@ds1.foo.example" may map to a Kerberos V
     principal name like: "ldap/ds1.foo.example/
     [email protected]"

  o  The domain-based name, of generic form,
     "[email protected]@kdc1.foo.example" may map to a Kerberos V
     principal name like: "kadmin/kdc1.foo.example/
     [email protected]"

5.  Security Considerations

  See [RFC5178].

  It is important for the security of protocols using the Kerberos V
  GSS-API mechanism and domain-based names, that the realm of domain-
  based principal names be derived from the hostname, rather than the
  domain name slots of the input domain-based name string.

6.  Normative References

  [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, March 1997.

  [RFC2743]  Linn, J., "Generic Security Service Application Program
             Interface Version 2, Update 1", RFC 2743, January 2000.

  [RFC3490]  Faltstrom, P., Hoffman, P., and A. Costello,
             "Internationalizing Domain Names in Applications (IDNA)",
             RFC 3490, March 2003.

  [RFC4120]  Neuman, C., Yu, T., Hartman, S., and K. Raeburn, "The
             Kerberos Network Authentication Service (V5)", RFC 4120,
             July 2005.

  [RFC4121]  Zhu, L., Jaganathan, K., and S. Hartman, "The Kerberos
             Version 5 Generic Security Service Application Program
             Interface (GSS-API) Mechanism: Version 2", RFC 4121,
             July 2005.

  [RFC5178]  Williams, N. and A. Melnikov, "Generic Security Service
             Application Program Interface (GSS-API)
             Internationalization and Domain-Based Service Names and
             Name Type", RFC 5178, May 2008.





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Author's Address

  Nicolas Williams
  Sun Microsystems
  5300 Riata Trace Ct.
  Austin, TX  78727
  US

  EMail: [email protected]










































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