HomeDocsIETF standardsRFCRFC 5500 — 5599
Text version
Network Working Group
Request for Comments: 5587
Category: Standards Track
N. Williams
Sun
July 2009

Extended Generic Security Service Mechanism Inquiry APIs

Abstract

This document introduces new application programming interfaces (APIs) to the Generic Security Services API (GSS-API) for extended mechanism attribute inquiry. These interfaces are primarily intended to reduce instances of hardcoding of mechanism identifiers in GSS applications.

These interfaces include mechanism attributes and attribute sets, a function for inquiring the attributes of a mechanism, a function for indicating mechanisms that possess given attributes, and a function for displaying mechanism attributes.

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.

Copyright Notice

Copyright © 2009 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 Provisions Relating to IETF Documents in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document.

Table of Contents

   1. Introduction ....................................................2
   2. Conventions Used in This Document ...............................2
   3. New GSS-API Interfaces ..........................................3
      3.1. Mechanism Attributes and Attribute Sets ....................3
      3.2. List of Known Mechanism Attributes .........................4
      3.3. Mechanism Attribute Sets of Existing Mechs .................6
      3.4. New GSS-API Function Interfaces ............................8
           3.4.1. Mechanism Attribute Criticality .....................8
           3.4.2. GSS_Indicate_mechs_by_attrs() .......................9
           3.4.3. GSS_Inquire_attrs_for_mech() .......................10
           3.4.4. GSS_Display_mech_attr() ............................10
           3.4.5. New Major Status Values ............................11
           3.4.6. C-Bindings .........................................11
   4. Requirements for Mechanism Designers ...........................13
   5. IANA Considerations ............................................13
   6. Security Considerations ........................................13
   7. References .....................................................13
      7.1. Normative References ......................................13
      7.2. Informative References ....................................14
Appendix A. Typedefs and C Bindings ..................................15

1. Introduction

GSS-API [RFC2743] mechanisms have a number of properties that may be of interest to applications. The lack of APIs for inquiring about available mechanisms' properties has meant that many GSS-API applications must hardcode mechanism Object Identifiers (OIDs). Ongoing work may result in a variety of new GSS-API mechanisms. Applications should not have to hardcode their OIDs.

For example, the Secure Shell version 2 (SSHv2) protocol [RFC4251] supports the use of GSS-API mechanisms for authentication [RFC4462] but explicitly prohibits the use of Simple and Protected GSS-API Negotiation (SPNEGO) [RFC4178]. Future mechanisms that negotiate mechanisms would have to be forbidden as well, but there is no way to implement applications that inquire what mechanisms are available and then programmatically exclude mechanisms "like SPNEGO".

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. New GSS-API Interfaces

We introduce a new concept -- that of mechanism attributes. By allowing applications to query the set of attributes associated with individual mechanisms and to find out which mechanisms support a given set of attributes, we allow applications to select mechanisms based on their attributes without having to hardcode mechanism OIDs.

Section 3.1 describes the mechanism attributes concept. Sections 3.4.2, 3.4.3, and 3.4.4 describe three new interfaces that deal in mechanisms and attribute sets:

  • GSS_Indicate_mechs_by_attrs()
  • GSS_Inquire_attrs_for_mech()
  • GSS_Display_mech_attr()

3.1. Mechanism Attributes and Attribute Sets

An abstraction for the features provided by mechanisms and pseudo- mechanisms is needed in order to facilitate the programmatic selection of mechanisms. Pseudo-mechanisms are mechanisms that make reference to other mechanisms in order to provide their services. For example, SPNEGO is a pseudo-mechanism, for without other mechanisms SPNEGO is useless.

Two data types are needed: one for individual mechanism attributes and one for mechanism attribute sets. To simplify the mechanism attribute interfaces, we reuse the 'OID' and 'OID set' data types and model individual mechanism attribute types as OIDs.

To this end, we define an open namespace of mechanism attributes and assign them arcs off of this OID: 

   <1.3.6.1.5.5.13>

Each mechanism has a set of mechanism attributes that it supports as described in its specification.

3.2. List of Known Mechanism Attributes

      +-------------------------+---------+-------------------------+
      | Mech Attr Name          | OID Arc | Arc Name                |
      +-------------------------+---------+-------------------------+
      | GSS_C_MA_MECH_CONCRETE  |     (1) | concrete-mech           |
      | GSS_C_MA_MECH_PSEUDO    |     (2) | pseudo-mech             |
      | GSS_C_MA_MECH_COMPOSITE |     (3) | composite-mech          |
      | GSS_C_MA_MECH_NEGO      |     (4) | mech-negotiation-mech   |
      | GSS_C_MA_MECH_GLUE      |     (5) | mech-glue               |
      | GSS_C_MA_NOT_MECH       |     (6) | not-mech                |
      | GSS_C_MA_DEPRECATED     |     (7) | mech-deprecated         |
      | GSS_C_MA_NOT_DFLT_MECH  |     (8) | mech-not-default        |
      | GSS_C_MA_ITOK_FRAMED    |     (9) | initial-is-framed       |
      | GSS_C_MA_AUTH_INIT      |    (10) | auth-init-princ         |
      | GSS_C_MA_AUTH_TARG      |    (11) | auth-targ-princ         |
      | GSS_C_MA_AUTH_INIT_INIT |    (12) | auth-init-princ-initial |
      | GSS_C_MA_AUTH_TARG_INIT |    (13) | auth-targ-princ-initial |
      | GSS_C_MA_AUTH_INIT_ANON |    (14) | auth-init-princ-anon    |
      | GSS_C_MA_AUTH_TARG_ANON |    (15) | auth-targ-princ-anon    |
      | GSS_C_MA_DELEG_CRED     |    (16) | deleg-cred              |
      | GSS_C_MA_INTEG_PROT     |    (17) | integ-prot              |
      | GSS_C_MA_CONF_PROT      |    (18) | conf-prot               |
      | GSS_C_MA_MIC            |    (19) | mic                     |
      | GSS_C_MA_WRAP           |    (20) | wrap                    |
      | GSS_C_MA_PROT_READY     |    (21) | prot-ready              |
      | GSS_C_MA_REPLAY_DET     |    (22) | replay-detection        |
      | GSS_C_MA_OOS_DET        |    (23) | oos-detection           |
      | GSS_C_MA_CBINDINGS      |    (24) | channel-bindings        |
      | GSS_C_MA_PFS            |    (25) | pfs                     |
      | GSS_C_MA_COMPRESS       |    (26) | compress                |
      | GSS_C_MA_CTX_TRANS      |    (27) | context-transfer        |
      | <reserved>              | (28...) |                         |
      +-------------------------+---------+-------------------------+

Table 1

   +-------------------------+-----------------------------------------+
   | Mech Attr Name          | Purpose                                 |
   +-------------------------+-----------------------------------------+
   | GSS_C_MA_MECH_CONCRETE  | Indicates that a mech is neither a      |
   |                         | pseudo-mechanism nor a composite        |
   |                         | mechanism.                              |
   | GSS_C_MA_MECH_PSEUDO    | Indicates that a mech is a              |
   |                         | pseudo-mechanism.                       |
   | GSS_C_MA_MECH_COMPOSITE | Indicates that a mech is a composite of |
   |                         | other mechanisms.  This is reserved for |
   |                         | a specification of "stackable"          |
   |                         | pseudo-mechanisms.                      |
   | GSS_C_MA_MECH_NEGO      | Indicates that a mech negotiates other  |
   |                         | mechs (e.g., SPNEGO has this            |
   |                         | attribute).                             |
   | GSS_C_MA_MECH_GLUE      | Indicates that the OID is not for a     |
   |                         | mechanism but for the GSS-API itself.   |
   | GSS_C_MA_NOT_MECH       | Indicates that the OID is known, yet it |
   |                         | is also known not to be the OID of any  |
   |                         | GSS-API mechanism (or of the GSS-API    |
   |                         | itself).                                |
   | GSS_C_MA_DEPRECATED     | Indicates that a mech (or its OID) is   |
   |                         | deprecated and MUST NOT be used as a    |
   |                         | default mechanism.                      |
   | GSS_C_MA_NOT_DFLT_MECH  | Indicates that a mech (or its OID) MUST |
   |                         | NOT be used as a default mechanism.     |
   | GSS_C_MA_ITOK_FRAMED    | Indicates that the given mechanism's    |
   |                         | initial context tokens are properly     |
   |                         | framed as per Section 3.1 of [RFC2743]. |
   | GSS_C_MA_AUTH_INIT      | Indicates support for authentication of |
   |                         | initiator to acceptor.                  |
   | GSS_C_MA_AUTH_TARG      | Indicates support for authentication of |
   |                         | acceptor to initiator.                  |
   | GSS_C_MA_AUTH_INIT_INIT | Indicates support for "initial"         |
   |                         | authentication of initiator to          |
   |                         | acceptor.  "Initial authentication"     |
   |                         | refers to the use of passwords, or keys |
   |                         | stored on tokens, for authentication.   |
   |                         | Whether a mechanism supports initial    |
   |                         | authentication may depend on IETF       |
   |                         | consensus (see Security                 |
   |                         | Considerations).                        |
   | GSS_C_MA_AUTH_TARG_INIT | Indicates support for initial           |
   |                         | authentication of acceptor to           |
   |                         | initiator.                              |
   | GSS_C_MA_AUTH_INIT_ANON | Indicates support for                   |
   |                         | GSS_C_NT_ANONYMOUS as an initiator      |
   |                         | principal name.                         |
   | GSS_C_MA_AUTH_TARG_ANON | Indicates support for                   |
   |                         | GSS_C_NT_ANONYMOUS as a target          |
   |                         | principal name.                         |
   | GSS_C_MA_DELEG_CRED     | Indicates support for credential        |
   |                         | delegation.                             |
   | GSS_C_MA_INTEG_PROT     | Indicates support for per-message       |
   |                         | integrity protection.                   |
   | GSS_C_MA_CONF_PROT      | Indicates support for per-message       |
   |                         | confidentiality protection.             |
   | GSS_C_MA_MIC            | Indicates support for Message Integrity |
   |                         | Code (MIC) tokens.                      |
   | GSS_C_MA_WRAP           | Indicates support for WRAP tokens.      |
   | GSS_C_MA_PROT_READY     | Indicates support for per-message       |
   |                         | protection prior to full context        |
   |                         | establishment.                          |
   | GSS_C_MA_REPLAY_DET     | Indicates support for replay detection. |
   | GSS_C_MA_OOS_DET        | Indicates support for out-of-sequence   |
   |                         | detection.                              |
   | GSS_C_MA_CBINDINGS      | Indicates support for channel bindings. |
   | GSS_C_MA_PFS            | Indicates support for Perfect Forward   |
   |                         | Security.                               |
   | GSS_C_MA_COMPRESS       | Indicates support for compression of    |
   |                         | data inputs to GSS_Wrap().              |
   | GSS_C_MA_CTX_TRANS      | Indicates support for security context  |
   |                         | export/import.                          |
   +-------------------------+-----------------------------------------+

Table 2

3.3. Mechanism Attribute Sets of Existing Mechs

The Kerberos V mechanism [RFC1964] provides the following mechanism attributes:

  • GSS_C_MA_MECH_CONCRETE
  • GSS_C_MA_ITOK_FRAMED
  • GSS_C_MA_AUTH_INIT
  • GSS_C_MA_AUTH_TARG
  • GSS_C_MA_DELEG_CRED
  • GSS_C_MA_INTEG_PROT
  • GSS_C_MA_CONF_PROT
  • GSS_C_MA_MIC
  • GSS_C_MA_WRAP
  • GSS_C_MA_PROT_READY
  • GSS_C_MA_REPLAY_DET
  • GSS_C_MA_OOS_DET
  • GSS_C_MA_CBINDINGS
   o  GSS_C_MA_CTX_TRANS (some implementations, using implementation-
      specific exported context token formats)

The Kerberos V mechanism also has a deprecated OID that has the same mechanism attributes as above as well as GSS_C_MA_DEPRECATED.

The mechanism attributes of the Simple Public-Key GSS-API Mechanism (SPKM) [RFC2025] family of mechanisms will be provided in a separate document, as SPKM is currently being reviewed for possibly significant changes due to problems in its specifications.

The Low Infrastructure Public Key (LIPKEY) mechanism [RFC2847] offers the following attributes:

  • GSS_C_MA_MECH_CONCRETE
  • GSS_C_MA_ITOK_FRAMED
  • GSS_C_MA_AUTH_INIT_INIT
  • GSS_C_MA_AUTH_TARG (from SPKM-3)
  • GSS_C_MA_AUTH_TARG_ANON (from SPKM-3)
  • GSS_C_MA_INTEG_PROT
  • GSS_C_MA_CONF_PROT
  • GSS_C_MA_REPLAY_DET
  • GSS_C_MA_OOS_DET
   o  GSS_C_MA_CTX_TRANS (some implementations, using implementation-
      specific exported context token formats)

(LIPKEY should also provide GSS_C_MA_CBINDINGS, but SPKM-3 requires clarifications on this point.)

The SPNEGO mechanism [RFC4178] provides the following attributes:

  • GSS_C_MA_MECH_NEGO
  • GSS_C_MA_ITOK_FRAMED

All other mechanisms' attributes will be described elsewhere.

3.4. New GSS-API Function Interfaces

Several new interfaces are given by which, for example, GSS-API applications may determine what features are provided by a given mechanism and what mechanisms provide what features.

These new interfaces are all OPTIONAL.

Applications should use GSS_Indicate_mechs_by_attrs() instead of GSS_Indicate_mechs() wherever possible.

Applications can use GSS_Indicate_mechs_by_attrs() to determine what, if any, mechanisms provide a given set of features.

GSS_Indicate_mechs_by_attrs() can also be used to indicate (as in GSS_Indicate_mechs()) the set of available mechanisms of each type (concrete, mechanism negotiation pseudo-mechanism, etc.).

3.4.1. Mechanism Attribute Criticality

Mechanism attributes may be added at any time. Not only may attributes be added to the list of known mechanism attributes at any time, but the set of mechanism attributes supported by a mechanism can be changed at any time.

For example, new attributes might be added to reflect whether a mechanism's initiator must contact an online infrastructure and/or whether the acceptor must do so. In this example, the Kerberos V mechanism would gain a new attribute even though the mechanism itself is not modified.

Applications making use of attributes not defined herein would then have no way of knowing whether a GSS-API implementation and its mechanisms know about new mechanism attributes. To address this problem, GSS_Indicate_mechs_by_attrs() and GSS_Inquire_attrs_for_mech() support a notion of critical mechanism attributes. Applications can search for mechanisms that understand mechanism attributes that are critical to the application, and the application may ask what mechanism attributes are understood by a given mechanism.

3.4.2. GSS_Indicate_mechs_by_attrs()

Inputs:

  • desired_mech_attrs SET OF OBJECT IDENTIFIER -- set of GSS_C_MA_* OIDs that the mechanisms indicated in the mechs output parameter MUST offer.
  • except_mech_attrs SET OF OBJECT IDENTIFIER -- set of GSS_C_MA_* OIDs that the mechanisms indicated in the mechs output parameter MUST NOT offer.
  • critical_mech_attrs SET OF OBJECT IDENTIFIER -- set of GSS_C_MA_* OIDs that the mechanisms indicated in the mechs output parameter MUST understand (i.e., mechs must know whether critical attributes are or are not supported).

Outputs:

  • major_status INTEGER
  • minor_status INTEGER
  • mechs SET OF OBJECT IDENTIFIER -- set of mechanisms that support the given desired_mech_attrs but not the except_mech_attrs, and all of which understand the given critical_mech_attrs (the caller must release this output with GSS_Release_oid_set()).

Return major_status codes:

  • GSS_S_COMPLETE indicates success; the output mechs parameter MAY be the empty set (GSS_C_NO_OID_SET).
  • GSS_S_FAILURE indicates that the request failed for some other reason.

GSS_Indicate_mechs_by_attrs() returns the set of OIDs corresponding to mechanisms that offer at least the desired_mech_attrs but none of the except_mech_attrs, and that understand all of the attributes listed in critical_mech_attrs.

When all three sets of OID input parameters are the empty set, this function acts as a version of GSS_indicate_mechs() that outputs the set of all supported mechanisms.

3.4.3. GSS_Inquire_attrs_for_mech()

Inputs:

  • mech OBJECT IDENTIFIER -- mechanism OID

Outputs:

  • major_status INTEGER
  • minor_status INTEGER
  • mech_attrs SET OF OBJECT IDENTIFIER -- set of mech_attrs OIDs (GSS_C_MA_*) supported by the mechanism (the caller must release this output with GSS_Release_oid_set()).
  • known_mech_attrs SET OF OBJECT IDENTIFIER -- set of mech_attrs OIDs known to the mechanism implementation (the caller must release this output with GSS_Release_oid_set()).

Return major_status codes:

  • GSS_S_COMPLETE indicates success; the output mech_attrs parameter MAY be the empty set (GSS_C_NO_OID_SET).
  • GSS_S_BAD_MECH indicates that the mechanism named by the mech parameter does not exist or that the mech is GSS_C_NO_OID and no default mechanism could be determined.
  • GSS_S_FAILURE indicates that the request failed for some other reason.

GSS_Inquire_attrs_for_mech() indicates the set of mechanism attributes supported by a given mechanism.

3.4.4. GSS_Display_mech_attr()

Inputs:

  • mech_attr OBJECT IDENTIFIER -- mechanism attribute OID

Outputs:

  • major_status INTEGER
  • minor_status INTEGER
   o  name OCTET STRING, -- name of mechanism attribute (e.g.,
      GSS_C_MA_*).
  • short_desc OCTET STRING, -- a short description of the mechanism attribute (the caller must release this output with GSS_Release_buffer()).
  • long_desc OCTET STRING -- a longer description of the mechanism attribute (the caller must release this output with GSS_Release_buffer()).

Return major_status codes:

  • GSS_S_COMPLETE indicates success.
  • GSS_S_BAD_MECH_ATTR indicates that the mechanism attribute referenced by the mech_attr parameter is unknown to the implementation.
  • GSS_S_FAILURE indicates that the request failed for some other reason.

This function can be used to obtain human-readable descriptions of GSS-API mechanism attributes.

3.4.5. New Major Status Values

A single, new, major status code is added for GSS_Display_mech_attr():

  • GSS_S_BAD_MECH_ATTR,

roughly corresponding to GSS_S_BAD_MECH but applicable to mechanism attribute OIDs rather than to mechanism OIDs.

For the C-bindings of the GSS-API [RFC2744], GSS_S_BAD_MECH_ATTR shall have a routine error number of 19 (this is shifted to the left by GSS_C_ROUTINE_ERROR_OFFSET).

3.4.6. C-Bindings

Note that there is a bug in the C bindings of the GSS-APIv2u1 [RFC2744] in that the C 'const' attribute is applied to types that are pointer typedefs. This is a bug because it declares that the pointer argument is 'const' rather than that the object pointed by it is const. To avoid this error, we hereby define new typedefs, which include const properly: 

      typedef const gss_buffer_desc * gss_const_buffer_t;
      typedef const struct gss_channel_bindings_struct *
         gss_const_channel_bindings_t;
      typedef const <platform-specific> gss_const_ctx_id_t;
      typedef const <platform-specific> gss_const_cred_id_t;
      typedef const <platform-specific> gss_const_name_t;
      typedef const gss_OID_desc * gss_const_OID;
      typedef const gss_OID_set_desc * gss_const_OID_set;

Figure 1: const typedefs

Note that only gss_const_OID and gss_const_OID_set are used below. We include the other const typedefs for convenience since the C bindings of the GSS-API do use const with pointer typedefs when it should often instead use the above typedefs instead.

#define GSS_S_BAD_MECH_ATTR (19ul << GSS_C_ROUTINE_ERROR_OFFSET)

OM_uint32 gss_indicate_mechs_by_attrs( 

         OM_uint32         *minor_status,
         gss_const_OID_set  desired_mech_attrs,
         gss_const_OID_set  except_mech_attrs,
         gss_const_OID_set  critical_mech_attrs,
         gss_OID_set       *mechs);

OM_uint32 gss_inquire_attrs_for_mech( 

         OM_uint32         *minor_status,
         gss_const_OID      mech,
         gss_OID_set       *mech_attrs,
         gss_OID_set       *known_mech_attrs);

OM_uint32 gss_display_mech_attr( 

         OM_uint32         *minor_status,
         gss_const_OID      mech_attr,
         gss_buffer_t       name,
         gss_buffer_t       short_desc,
         gss_buffer_t       long_desc);

Figure 2: C bindings

Note that output buffers must be released via gss_release_buffer(). Output OID sets must be released via gss_release_oid_set().

Please see Appendix A for a full set of typedef fragments defined in this document and the necessary code license.

4. Requirements for Mechanism Designers

All future GSS-API mechanism specifications MUST:

  • list the set of GSS-API mechanism attributes associated with them.

5. IANA Considerations

The namespace of programming-language symbols with names beginning with GSS_C_MA_* is reserved for allocation by IETF Consensus. IANA allocated a base OID, as an arc of 1.3.6.1.5.5, for the set of GSS_C_MA_* described herein, and registered all of the GSS_C_MA_* values described in Section 3.2.

6. Security Considerations

This document specifies extensions to a security-related API. It imposes new requirements on future GSS-API mechanisms, and the specifications of future protocols that use the GSS-API should make reference to this document where applicable. The ability to inquire about specific properties of mechanisms should improve security.

The semantics of each mechanism attribute may include a security component.

Application developers must understand that mechanism attributes may be added at any time -- both to the set of known mechanism attributes as well as to existing mechanisms' sets of supported mechanism attributes. Therefore, application developers using the APIs described herein must understand what mechanism attributes their applications depend critically on, and must use the mechanism attribute criticality features of these APIs.

7. References

7.1. 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.
   
   [RFC2744]  Wray, J., "Generic Security Service API Version 2 :
              C-bindings", RFC 2744, January 2000.

7.2. Informative References

   [RFC1964]  Linn, J., "The Kerberos Version 5 GSS-API Mechanism",
              RFC 1964, June 1996.
   
   [RFC2025]  Adams, C., "The Simple Public-Key GSS-API Mechanism
              (SPKM)", RFC 2025, October 1996.
   
   [RFC2847]  Eisler, M., "LIPKEY - A Low Infrastructure Public Key
              Mechanism Using SPKM", RFC 2847, June 2000.
   
   [RFC4178]  Zhu, L., Leach, P., Jaganathan, K., and W. Ingersoll, "The
              Simple and Protected Generic Security Service Application
              Program Interface (GSS-API) Negotiation Mechanism",
              RFC 4178, October 2005.
   
   [RFC4251]  Ylonen, T. and C. Lonvick, "The Secure Shell (SSH)
              Protocol Architecture", RFC 4251, January 2006.
   
   [RFC4462]  Hutzelman, J., Salowey, J., Galbraith, J., and V. Welch,
              "Generic Security Service Application Program Interface
              (GSS-API) Authentication and Key Exchange for the Secure
              Shell (SSH) Protocol", RFC 4462, May 2006.

Appendix A. Typedefs and C Bindings

This appendix contains the full set of code fragments defined in this document.

Copyright © 2009 IETF Trust and the persons identified as authors of the code. All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

  • Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
  • Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
  • Neither the name of Internet Society, IETF or IETF Trust, nor the names of specific contributors, may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 

   typedef const gss_buffer_desc * gss_const_buffer_t;
   typedef const struct gss_channel_bindings_struct *
      gss_const_channel_bindings_t;
   typedef const <platform-specific> gss_const_ctx_id_t;
   typedef const <platform-specific> gss_const_cred_id_t;
   typedef const <platform-specific> gss_const_name_t;
   typedef const gss_OID_desc * gss_const_OID;
   typedef const gss_OID_set_desc * gss_const_OID_set;

#define GSS_S_BAD_MECH_ATTR (19ul << GSS_C_ROUTINE_ERROR_OFFSET)

OM_uint32 gss_indicate_mechs_by_attrs( 

      OM_uint32         *minor_status,
      gss_const_OID_set  desired_mech_attrs,
      gss_const_OID_set  except_mech_attrs,
      gss_const_OID_set  critical_mech_attrs,
      gss_OID_set       *mechs);

OM_uint32 gss_inquire_attrs_for_mech( 

      OM_uint32         *minor_status,
      gss_const_OID      mech,
      gss_OID_set       *mech_attrs,
      gss_OID_set       *known_mech_attrs);

OM_uint32 gss_display_mech_attr( 

      OM_uint32         *minor_status,
      gss_const_OID      mech_attr,
      gss_buffer_t       name,
      gss_buffer_t       short_desc,
      gss_buffer_t       long_desc);

Author's Address

   Nicolas Williams
   Sun Microsystems
   5300 Riata Trace Ct
   Austin, TX  78727
   US
   
   EMail: Nicolas.Williams@sun.com