draft-ietf-kitten-gssapi-domain-based-names-06.txt   rfc5178.txt 
NETWORK WORKING GROUP N. Williams Network Working Group N. Williams
Internet-Draft Sun Request for Comments: 5178 Sun
Expires: July 27, 2008 A. Melnikov Category: Standards Track A. Melnikov
Isode Ltd. Isode Ltd.
January 24, 2008
GSS-API Internationalization and Domain-Based Service Names and Name
Type
draft-ietf-kitten-gssapi-domain-based-names-06.txt
Status of this Memo
By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on July 27, 2008. Generic Security Service Application Program Interface (GSS-API)
Internationalization and Domain-Based Service Names and Name Type
Copyright Notice Status of This Memo
Copyright (C) The IETF Trust (2008). 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 Abstract
This document describes domainname-based service principal names and This document describes domain-name-based service principal names and
the corresponding name type for the Generic Security Service the corresponding name type for the Generic Security Service
Application Programming Interface (GSS-API). Internationalization of Application Programming Interface (GSS-API). Internationalization of
the GSS-API is also covered. the GSS-API is also covered.
Domain-based service names are similar to host-based service names, Domain-based service names are similar to host-based service names,
but using a domain name (not necessarily an Internet domain name) in but using a domain name (not necessarily an Internet domain name) in
addition to a hostname. The primary purpose of domain-based names is addition to a hostname. The primary purpose of domain-based names is
to provide a measure of protection to applications that utilize to provide a measure of protection to applications that utilize
insecure service discovery protocols. This is achieved by providing insecure service discovery protocols. This is achieved by providing
a way to name clustered services after the "domain" which they a way to name clustered services after the "domain" which they
service, thereby allowing their clients to authorize the service's service, thereby allowing their clients to authorize the service's
servers based on authentication of their service names. servers based on authentication of their service names.
Table of Contents Table of Contents
1. Conventions used in this document . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Conventions Used in This Document . . . . . . . . . . . . . . . 4
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . 5 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Name Type OID and Symbolic Name . . . . . . . . . . . . . . 5 3.1. Name Type OID . . . . . . . . . . . . . . . . . . . . . . . 4
4. Query and Display Syntaxes . . . . . . . . . . . . . . . . . 6 3.2. Name Type OID and Symbolic Name . . . . . . . . . . . . . . 4
4.1. Examples of domain-based names . . . . . . . . . . . . . . . 6 4. Query and Display Syntaxes . . . . . . . . . . . . . . . . . . 4
5. Internationalization (I18N) considerations . . . . . . . . . 7 4.1. Examples of Domain-Based Names . . . . . . . . . . . . . . 5
5.1. Importing internationalized names . . . . . . . . . . . . . 7 5. Internationalization (I18N) Considerations . . . . . . . . . . 5
5.2. Displaying internationalized names . . . . . . . . . . . . . 7 5.1. Importing Internationalized Names . . . . . . . . . . . . . 5
6. Application protocol examples . . . . . . . . . . . . . . . 8 5.2. Displaying Internationalized Names . . . . . . . . . . . . 5
6.1. NFSv4 domain-wide namespace root server discovery . . . . . 8 6. Application Protocol Examples . . . . . . . . . . . . . . . . . 6
6.2. LDAP server discovery . . . . . . . . . . . . . . . . . . . 8 6.1. NFSv4 Domain-Wide Namespace Root Server Discovery . . . . . 6
7. Security Considerations . . . . . . . . . . . . . . . . . . 9 6.2. LDAP Server Discovery . . . . . . . . . . . . . . . . . . . 6
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 7. Security Considerations . . . . . . . . . . . . . . . . . . . . 7
8.1. Normative References . . . . . . . . . . . . . . . . . . . . 10 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
8.2. Informative References . . . . . . . . . . . . . . . . . . . 10 8.1. Normative References . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . 12 8.2. Informative References . . . . . . . . . . . . . . . . . . 8
Intellectual Property and Copyright Statements . . . . . . . 13
1. 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].
2. Introduction 1. Introduction
Some applications need to discover the names of servers for a Some applications need to discover the names of servers for a
specific resource. Some common methods for server discovery are specific resource. Some common methods for server discovery are
insecure, e.g., queries for DNS [RFC1035] SRV resource records insecure, e.g., queries for DNS [RFC1035] SRV resource records
[RFC2782] without using DNSSEC [RFC4033] and subject to attacks [RFC2782] without using DNSSEC [RFC4033], and are subject to attacks
whereby a client can be re-directed to incorrect and possibly whereby a client can be re-directed to incorrect and possibly
malicious servers. A client may even be re-directed to a server that malicious servers. A client may even be re-directed to a server that
has credentials for itself and may thus authenticate itself to the has credentials for itself and thus may authenticate itself to the
client, and yet it could be incorrect or malicious (because it has client, and yet it could be incorrect or malicious (because it has
been compromised, say). been compromised, say).
Domain-based names allow for GSS-API [RFC2743] initiator applications Domain-based names allow for GSS-API [RFC2743] initiator applications
(clients) to authorize acceptor principals (servers) to serve the (clients) to authorize acceptor principals (servers) to serve the
resource for which the client used insecure server discovery without resource for which the client used insecure server discovery without
either securing the server discovery method nor requiring an either securing the server discovery method or requiring an
additional protocol for server authorization -- either a discovered additional protocol for server authorization. That is, either a
server has credentials for authenticating the domain-based service discovered server has credentials for authenticating the domain-based
names that it is intended to respond to, or it does not. service names that it is intended to respond to, or it does not.
Availability of valid credentials for authenticating domain-based Availability of valid credentials for authenticating domain-based
names embodies the authorization of a given server to a domain-wide names embodies the authorization of a given server to a domain-wide
service. service.
A domain-based name consists of three required elements: A domain-based name consists of three required elements:
o a service name o a service name
o a domain name o a domain name
o a hostname o a hostname
The domain name and the hostname should be Domain Name System (DNS) The domain name and the hostname should be Domain Name System (DNS)
names, though domain-based names could be used in non-DNS names, though domain-based names could be used in non-DNS
environments. Because of the use of DNS names we must also provide environments. Because of the use of DNS names we must also provide
for internationalization of the GSS-API. for internationalization of the GSS-API.
Note that domain-based naming isn't new. According to a report to Note that domain-based naming isn't new. According to a report to
the KITTEN WG mailing list there exists at least one implementation the KITTEN WG mailing list, there exists at least one implementation
of LDAP which uses domain-based service naming, and the DIGEST-MD5 of LDAP which uses domain-based service naming, and the DIGEST-MD5
HTTP/SASL mechanism [RFC2831] describes a similar notion (see section HTTP / Simple Authentication and Security Layer (SASL) mechanism
2.1.2, description of the "serv-name" field of the digest-response). [RFC2831] describes a similar notion. (See section 2.1.2 of
[RFC2831] for a description of the "serv-name" field of the digest-
response.)
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. IANA Considerations 3. IANA Considerations
3.1. Name Type OID and Symbolic Name 3.1. Name Type OID
This document creates a new GSS-API name-type, with a symbol name of The IANA has recorded the following new name-type OID in IANA's "SMI
"GSS_C_NT_DOMAINBASED_SERVICE" and this OID: Security for Name System Designators Codes (nametypes)" registry:
{iso(1) org(3) dod(6) internet(1) security(5) nametypes(6) gss- 5 gss-domain-based-services [RFC5178]
domain-based(5)}
allocated manually with RFC2743 as the authoritative "registry" -- 3.2. Name Type OID and Symbolic Name
there is no IANA registry for GSS-API name types at this time.
Therefore there are no IANA considerations in this document. This document creates a new GSS-API name-type, with a symbolic name
of "GSS_C_NT_DOMAINBASED_SERVICE" and this OID:
{iso(1) org(3) dod(6) internet(1) security(5) nametypes(6) gss-
domain-based(5)}
4. Query and Display Syntaxes 4. Query and Display Syntaxes
There is a single name syntax for domain-based names. It is There is a single name syntax for domain-based names. It is
expressed using the ABNF [RFC4234]. expressed using the ABNF [RFC5234].
The syntax is: The syntax is:
domain-based-name = domain-based-name = service "@" domain "@" hostname
service "@" domain "@" hostname
hostname =
domain
domain =
sub-domain 1*("." sub-domain)
sub-domain =
Let-dig [Ldh-str] hostname = domain
Let-dig = domain = sub-domain 1*("." sub-domain)
ALPHA / DIGIT sub-domain = Let-dig [Ldh-str]
Ldh-str = Let-dig = ALPHA / DIGIT
*( ALPHA / DIGIT / "-" ) Let-dig Ldh-str = *( ALPHA / DIGIT / "-" ) Let-dig
Where <service> is defined in Section 4.1 of [RFC2743]. Other rules Where <service> is defined in Section 4.1 of [RFC2743]. Other rules
not defined above are defined in Appendix B.1 of [RFC4234]. not defined above are defined in Appendix B.1 of [RFC5234].
4.1. Examples of domain-based names 4.1. Examples of Domain-Based Names
These examples are not normative: These examples are not normative:
o ldap@somecompany.example@ds1.somecompany.example o ldap@somecompany.example@ds1.somecompany.example
o nfs@somecompany.example@nfsroot1.somecompany.example o nfs@somecompany.example@nfsroot1.somecompany.example
The .example top-level domain is used here in accordance with The .example top-level domain is used here in accordance with
[RFC2606]. [RFC2606].
5. Internationalization (I18N) considerations 5. Internationalization (I18N) Considerations
We introduce new versions of GSS_Import_name() and GSS_Display_name() We introduce new versions of GSS_Import_name() and GSS_Display_name()
to better support Unicode. Additionally we provide for the use of to better support Unicode. Additionally, we provide for the use of
ACE-encoded DNS in the non-internationalized interfaces [RFC3490]. ASCII Compatible Encoding (ACE)-encoded DNS in the non-
internationalized interfaces [RFC3490].
5.1. Importing internationalized names 5.1. Importing Internationalized Names
When the input_name_type parameter is the When the input_name_type parameter is the
GSS_C_NT_DOMAINBASED_SERVICE OID then GSS_Import_name() GSS_C_NT_DOMAINBASED_SERVICE OID, then GSS_Import_name()
implementations and GSS-API mechanisms MUST accept ACE-encoded implementations and GSS-API mechanisms MUST accept ACE-encoded
internationalized domain names in the hostname and domain name slots internationalized domain names in the hostname and domain name slots
of the given domain-based name string. of the given domain-based name string.
Support for non-ASCII internationalized domain names SHOULD also be Support for non-ASCII internationalized domain names SHOULD also be
provided through a new function, GSS_Import_name_utf8(), that provided through a new function, GSS_Import_name_utf8(), that
operates exactly like GSS_Import_name() (with the same input and operates exactly like GSS_Import_name() (with the same input and
output parameters and behaviour), except that it MUST accept output parameters and behavior), except that it MUST accept
internationalized domain names both, as UTF-8 strings and as ACE- internationalized domain names both as UTF-8 strings and as ACE-
encoded strings via its input_name_string argument. encoded strings via its input_name_string argument.
5.2. Displaying internationalized names 5.2. Displaying Internationalized Names
Implementations of GSS_Display_name() MUST only output US-ASCII or Implementations of GSS_Display_name() MUST only output US-ASCII or
ACE-encoded internationalized domain names in the hostname and domain ACE-encoded internationalized domain names in the hostname and domain
name slots of domain-based names (or mechanism names (MN) that name slots of domain-based names (or mechanism names (MN) that
conform to the mechanism's form for domain-based names). conform to the mechanism's form for domain-based names).
Support for non-ASCII internationalized domain names SHOULD also be Support for non-ASCII internationalized domain names SHOULD also be
provided through a new function, GSS_Display_name_utf8(), that provided through a new function, GSS_Display_name_utf8(), that
operates exactly like GSS_Display_name() (with the same input and operates exactly like GSS_Display_name() (with the same input and
output parameters and behaviour), except that it outputs UTF-8 output parameters and behavior), except that it outputs UTF-8 strings
strings via its name_string output argument. GSS_Display_name_utf8() via its name_string output argument. GSS_Display_name_utf8() MUST
MUST NOT output ACE-encoded internationalized domain names. NOT output ACE-encoded internationalized domain names.
6. Application protocol examples 6. Application Protocol Examples
The following examples are not normative. They describe how the The following examples are not normative. They describe how the
author envisions two applications' use of domain-based names. authors envision two applications' use of domain-based names.
6.1. NFSv4 domain-wide namespace root server discovery 6.1. NFSv4 Domain-Wide Namespace Root Server Discovery
Work is ongoing to provide a method for constructing domain-wide Work is ongoing to provide a method for constructing domain-wide
NFSv4 [RFC3530] filesystem namespaces where there is a single "root" NFSv4 [RFC3530] filesystem namespaces where there is a single "root"
with one or more servers (replicas) and multiple filesystems glued with one or more servers (replicas) and multiple filesystems glued
into the namespace through use of "referrals." Clients could then into the namespace through use of "referrals". Clients could then
construct a "global" namespace through use of the DNS domain construct a "global" namespace through use of the DNS domain
hierarchy. hierarchy.
Here clients would always know, from context, when they need to find Here, clients would always know, from context, when they need to find
the root servers for a given DNS domain. Root server discovery would the root servers for a given DNS domain. Root server discovery would
be performed using DNS SRV RR lookups, without using DNSSEC where be performed using DNS SRV RR lookups, without using DNSSEC where
DNSSEC has not been deployed. DNSSEC has not been deployed.
When using RPCSEC_GSS [RFC2203] for security NFSv4 clients would then When using RPCSEC_GSS [RFC2203] for security, NFSv4 clients would use
use domain-based names to ensure that that the servers named in the domain-based names to ensure that the servers named in the SRV RRs
SRV RRs are in fact authorized to be the NFSv4 root servers for the are in fact authorized to be the NFSv4 root servers for the target
target domain. domain.
6.2. LDAP server discovery 6.2. LDAP Server Discovery
LDAP clients using the GSS-API through SASL too would benefit from LDAP clients using the GSS-API through SASL would also benefit from
use of domain-based names to protect server discovery through use of domain-based names to protect server discovery through
insecure DNS SRV RR lookups, much as described above. insecure DNS SRV RR lookups, much as described above.
Unlike NFSv4 clients, not all LDAP clients may always know from Unlike NFSv4 clients, not all LDAP clients always know from context
context when they should use domain-based names. That's because when they should use domain-based names. That's because existing
existing clients may use host-based naming to authenticate servers clients may use host-based naming to authenticate servers discovered
discovered through SRV RR lookups. Changing such clients to use through SRV RR lookups. Changing such clients to use domain-based
domain-based naming when domain-based acceptor credentials have not naming when domain-based acceptor credentials have not been deployed
been deployed to LDAP servers, or when LDAP servers have not been to LDAP servers, or when LDAP servers have not been modified to allow
modified to allow use of domain-based naming, would break use of domain-based naming, would break interoperability. That is,
interoperability. That is, there is a legacy server interoperability there is a legacy server interoperability issue here. Therefore,
issue here. Therefore LDAP clients may require additional LDAP clients may require additional configuration at deployment time
configuration at deployment time to enable (or disable) use of to enable (or disable) use of domain-based naming.
domain-based naming.
Note: whether SASL [RFC4422] or its GSS-API bridges [RFC4752] Note: whether SASL [RFC4422] or its GSS-API bridges [RFC4752] [GS2]
[I-D.josefsson-sasl-gs2] require updates in order allow use of require updates in order allow use of domain-based names is not
domain-based names is not relevant to the theory of how domain-based relevant to the theory of how domain-based naming would protect LDAP
naming would protect LDAP clients' server discovery. clients' server discovery.
7. Security Considerations 7. Security Considerations
Use of GSS-API domain-based names may not be negotiable by some GSS- Use of GSS-API domain-based names may not be negotiable by some GSS-
API mechanisms, and some acceptors may not support GSS-API domain- API mechanisms, and some acceptors may not support GSS-API domain-
based names. In such cases initiators are left to fallback on the based names. In such cases, the initiators are left to fall back on
use of hostbased names, in which case the initiators MUST also verify the use of host-based names, so the initiators MUST also verify that
that the acceptor's hostbased name is authorized to provide the given the acceptor's host-based name is authorized to provide the given
service for the domain that the initiator had wanted. service for the domain that the initiator had wanted.
The above security consideration also applies to all GSS-API The above security consideration also applies to all GSS-API
initiators who lack support for domain-based service names. initiators who lack support for domain-based service names.
Note that, as with all service names, the mere existence of a domain-
based service name conveys meaningful information that may be used by
initiators for making authorization decisions; therefore,
administrators of distributed authentication services should be aware
of the significance of the service names for which they create
acceptor credentials.
8. References 8. References
8.1. Normative References 8.1. Normative References
[RFC1035] Mockapetris, P., "Domain names - implementation and [RFC1035] Mockapetris, P., "Domain names - implementation and
specification", STD 13, RFC 1035, November 1987. specification", STD 13, RFC 1035, November 1987.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
skipping to change at page 10, line 29 skipping to change at page 7, line 48
specifying the location of services (DNS SRV)", RFC 2782, specifying the location of services (DNS SRV)", RFC 2782,
February 2000. February 2000.
[RFC2831] Leach, P. and C. Newman, "Using Digest Authentication as a [RFC2831] Leach, P. and C. Newman, "Using Digest Authentication as a
SASL Mechanism", RFC 2831, May 2000. SASL Mechanism", RFC 2831, May 2000.
[RFC3490] Faltstrom, P., Hoffman, P., and A. Costello, [RFC3490] Faltstrom, P., Hoffman, P., and A. Costello,
"Internationalizing Domain Names in Applications (IDNA)", "Internationalizing Domain Names in Applications (IDNA)",
RFC 3490, March 2003. RFC 3490, March 2003.
[RFC4234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", RFC 4234, October 2005. Specifications: ABNF", STD 68, RFC 5234, January 2008.
8.2. Informative References 8.2. Informative References
[I-D.josefsson-sasl-gs2] [GS2] Josefsson, S., "Using GSS-API Mechanisms in SASL: The GS2
Josefsson, S., "Using GSS-API Mechanisms in SASL: The GS2 Mechanism Family", Work in Progress, October 2007.
Mechanism Family", draft-josefsson-sasl-gs2-00 (work in
progress), November 2005.
[RFC2203] Eisler, M., Chiu, A., and L. Ling, "RPCSEC_GSS Protocol [RFC2203] Eisler, M., Chiu, A., and L. Ling, "RPCSEC_GSS Protocol
Specification", RFC 2203, September 1997. Specification", RFC 2203, September 1997.
[RFC2606] Eastlake, D. and A. Panitz, "Reserved Top Level DNS [RFC2606] Eastlake, D. and A. Panitz, "Reserved Top Level DNS
Names", BCP 32, RFC 2606, June 1999. Names", BCP 32, RFC 2606, June 1999.
[RFC3530] Shepler, S., Callaghan, B., Robinson, D., Thurlow, R., [RFC3530] Shepler, S., Callaghan, B., Robinson, D., Thurlow, R.,
Beame, C., Eisler, M., and D. Noveck, "Network File System Beame, C., Eisler, M., and D. Noveck, "Network File System
(NFS) version 4 Protocol", RFC 3530, April 2003. (NFS) version 4 Protocol", RFC 3530, April 2003.
skipping to change at page 12, line 9 skipping to change at page 8, line 35
Security Layer (SASL)", RFC 4422, June 2006. Security Layer (SASL)", RFC 4422, June 2006.
[RFC4752] Melnikov, A., "The Kerberos V5 ("GSSAPI") Simple [RFC4752] Melnikov, A., "The Kerberos V5 ("GSSAPI") Simple
Authentication and Security Layer (SASL) Mechanism", Authentication and Security Layer (SASL) Mechanism",
RFC 4752, November 2006. RFC 4752, November 2006.
Authors' Addresses Authors' Addresses
Nicolas Williams Nicolas Williams
Sun Microsystems Sun Microsystems
5300 Riata Trace Ct 5300 Riata Trace Ct.
Austin, TX 78727 Austin, TX 78727
US US
Email: Nicolas.Williams@sun.com EMail: Nicolas.Williams@sun.com
Alexey Melnikov Alexey Melnikov
Isode Ltd. Isode Ltd.
5 Castle Business Village, 5 Castle Business Village,
36 Station Road 36 Station Road
Hampton, Middlesex TW12 2BX Hampton, Middlesex TW12 2BX
United Kingdom United Kingdom
Email: Alexey.Melnikov@isode.com EMail: Alexey.Melnikov@isode.com
Full Copyright Statement Full Copyright Statement
Copyright (C) The IETF Trust (2008). Copyright (C) The IETF Trust (2008).
This document is subject to the rights, licenses and restrictions This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors contained in BCP 78, and except as set forth therein, the authors
retain all their rights. retain all their rights.
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
skipping to change at page 13, line 44 skipping to change at line 366
attempt made to obtain a general license or permission for the use of attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr. http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at this standard. Please address the information to the IETF at
ietf-ipr@ietf.org. ietf-ipr@ietf.org.
Acknowledgment
Funding for the RFC Editor function is provided by the IETF
Administrative Support Activity (IASA).
 End of changes. 52 change blocks. 
147 lines changed or deleted 120 lines changed or added

This html diff was produced by rfcdiff 1.34. The latest version is available from http://tools.ietf.org/tools/rfcdiff/