draft-ietf-kitten-extended-mech-inquiry-02.txt   draft-ietf-kitten-extended-mech-inquiry-03.txt 
NETWORK WORKING GROUP N. Williams NETWORK WORKING GROUP N. Williams
Internet-Draft Sun Internet-Draft Sun
Expires: December 28, 2006 June 26, 2006 Expires: August 28, 2008 February 25, 2008
Extended Generic Security Service Mechanism Inquiry APIs Extended Generic Security Service Mechanism Inquiry APIs
draft-ietf-kitten-extended-mech-inquiry-02.txt draft-ietf-kitten-extended-mech-inquiry-03.txt
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Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2006). Copyright (C) The IETF Trust (2008).
Abstract Abstract
This document introduces new application programming interfaces This document introduces new application programming interfaces
(APIs) to the Generic Security Services API (GSS-API) for extended (APIs) to the Generic Security Services API (GSS-API) for extended
mechanism attribute inquiry. These interfaces are primarily intended mechanism attribute inquiry. These interfaces are primarily intended
for use in mechanism composition, but also to reduce instances of to reduce instances of hardcoding of mechanism identifiers in GSS
hardcoding of mechanism identifiers in GSS applications. applications.
These interfaces include: mechanism attributes and attribute sets, a These interfaces include: mechanism attributes and attribute sets, a
function for inquiring the attributes of a mechanism, a function for function for inquiring the attributes of a mechanism, a function for
indicating mechanisms that posses given attributes, and a function indicating mechanisms that posses given attributes, and a function
for displaying mechanism attributes. for displaying mechanism attributes.
Table of Contents Table of Contents
1. Conventions used in this document . . . . . . . . . . . . 3 1. Conventions used in this document . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . 3
3. New GSS-API Interfaces . . . . . . . . . . . . . . . . . . 3 3. New GSS-API Interfaces . . . . . . . . . . . . . . . . . . 3
3.1. Mechanism Attributes and Attribute Sets . . . . . . . . . 3 3.1. Mechanism Attributes and Attribute Sets . . . . . . . . . 3
3.2. Determination of Attribute Sets of Composite Mechs . . . . 4 3.2. List of Known Mechanism Attributes . . . . . . . . . . . . 4
3.3. List of Known Mechanism Attributes . . . . . . . . . . . . 4 3.3. Mechanism Attribute Sets of Existing Mechs . . . . . . . . 6
3.4. Mechanism Attribute Sets of Existing Mechs . . . . . . . . 6 3.4. New GSS-API Function Interfaces . . . . . . . . . . . . . 7
3.5. New GSS-API Function Interfaces . . . . . . . . . . . . . 8 3.4.1. GSS_Indicate_mechs_by_attr() . . . . . . . . . . . . . . . 8
3.5.1. GSS_Indicate_mechs_by_attr() . . . . . . . . . . . . . . . 8 3.4.2. GSS_Inquire_attrs_for_mech() . . . . . . . . . . . . . . . 8
3.5.2. GSS_Inquire_attrs_for_mech() . . . . . . . . . . . . . . . 9 3.4.3. GSS_Display_mech_attr() . . . . . . . . . . . . . . . . . 9
3.5.3. GSS_Display_mech_attr() . . . . . . . . . . . . . . . . . 10 3.4.4. New Major Status Values . . . . . . . . . . . . . . . . . 9
3.5.4. New Major Status Values . . . . . . . . . . . . . . . . . 10 3.4.5. C-Bindings . . . . . . . . . . . . . . . . . . . . . . . . 9
3.5.5. C-Bindings . . . . . . . . . . . . . . . . . . . . . . . . 10 4. Requirements for Mechanism Designers . . . . . . . . . . . 10
4. Requirements for Mechanism Designers . . . . . . . . . . . 11 5. IANA Considerations . . . . . . . . . . . . . . . . . . . 10
5. IANA Considerations . . . . . . . . . . . . . . . . . . . 11 6. Security considerations . . . . . . . . . . . . . . . . . 10
6. Security considerations . . . . . . . . . . . . . . . . . 11 7. References . . . . . . . . . . . . . . . . . . . . . . . . 11
7. References . . . . . . . . . . . . . . . . . . . . . . . . 12 7.1. Normative References . . . . . . . . . . . . . . . . . . . 11
7.1. Normative . . . . . . . . . . . . . . . . . . . . . . . . 12 7.2. Informative References . . . . . . . . . . . . . . . . . . 11
7.2. Normative . . . . . . . . . . . . . . . . . . . . . . . . 12 Author's Address . . . . . . . . . . . . . . . . . . . . . 11
Author's Address . . . . . . . . . . . . . . . . . . . . . 13 Intellectual Property and Copyright Statements . . . . . . 12
Intellectual Property and Copyright Statements . . . . . . 14
1. Conventions used in this document 1. Conventions used in this document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
2. Introduction 2. Introduction
3. New GSS-API Interfaces 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 OIDs. Ongoing work may result
in a variety of new GSS-API mechanisms. Applications should not have
to hardcode their OIDs.
GSS-API applications face, today, the problem of how to select from For example, the SSHv2 protocol [RFC4251] supports the use of GSS-API
multiple GSS-API mechanisms that may be available. For example, mechanisms for authentication [RFC4462], but it explicitly prohibits
applications that support mechanism negotiation directly often have the use of SPNEGO [RFC4178]. Future mechanisms that negotiate
to be careful not to use SPNEGO to avoid two-layer mechanism mechanisms would have to be forbidden as well, but there is no way to
negotiation, but since SPNEGO may be indicated by implement applications that inquire what mechanisms are available and
GSS_Indicate_mechs() and since there's no way to know that a then programmatically exclude mechanisms "like SPNEGO".
mechanism negotiates mechanisms other than to hardcode the OIDs of
such mechanisms, such applications must hardcode the SPNEGO OID.
This problem is likely to be exacerbated by the introduction of
composite mechanisms.
To address this problem we introduce a new concept: that of mechanism 3. New GSS-API Interfaces
attributes. By allowing applications to query the set of attributes
associated with individual mechanisms and to find out which We introduce a new concept: that of mechanism attributes. By
mechanisms support a given set of attributes we allow applications to allowing applications to query the set of attributes associated with
select mechanisms based on their attributes yet without having to individual mechanisms and to find out which mechanisms support a
hardcode mechanism OIDs. given set of attributes we allow applications to select mechanisms
based on their attributes yet without having to hardcode mechanism
OIDs.
Section 3.1 describes the mechanism attributes concept. Sections Section 3.1 describes the mechanism attributes concept. Sections
3.5.1, 3.5.2 and 3.5.3 describe three new interfaces that deal in 3.4.1, 3.4.2 and 3.4.3 describe three new interfaces that deal in
mechanisms and attribute sets: mechanisms and attribute sets:
o GSS_Indicate_mechs_by_attrs() o GSS_Indicate_mechs_by_attrs()
o GSS_Inquire_attrs_for_mech() o GSS_Inquire_attrs_for_mech()
o GSS_Display_mech_attr() o GSS_Display_mech_attr()
3.1. Mechanism Attributes and Attribute Sets 3.1. Mechanism Attributes and Attribute Sets
An abstraction for the features provided by pseudo-mechanisms is An abstraction for the features provided by pseudo-mechanisms is
needed in order to facilitate the programmatic selection of needed in order to facilitate the programmatic selection of
mechanisms as well as for the programmatic composition of mechanisms. mechanisms.
Two data types are needed: one for individual mechanism attributes Two data types are needed: one for individual mechanism attributes
and one for mechanism attribute sets. To simplify the mechanism and one for mechanism attribute sets. To simplify the mechanism
attributes interfaces we reuse the 'OID' and 'OID set' data types and attributes interfaces we reuse the 'OID' and 'OID set' data types and
model individual mechanism attribute types as OIDs. model individual mechanism attribute types as OIDs.
To this end we define an open namespace of mechanism attributes and To this end we define an open namespace of mechanism attributes and
assign them arcs off of this OID: assign them arcs off of this OID:
<TBD> [1.3.6.1.5.5.12 appears to be available, registration w/ IANA <TBD> [1.3.6.1.5.5.12 appears to be available]
TBD]
3.2. Determination of Attribute Sets of Composite Mechs
Each mechanism, composite or otherwise, has a set of mechanism
attributes that it supports as specified.
The mechanism attribute set of a composite mechanism is to be
determined by the top-most stackable pseudo-mechanism of the
composite according to its own attribute set and that of the
remainder of the composite mechanism stack below it.
It may well be that some composite mechanisms' attribute sets consist
of the union of those of their every component, however this need not
be the case and MUST NOT be assumed.
Every stackable pseudo-mechanism's specification MUST specify the Each mechanism has a set of mechanism attributes that it supports as
rules for determining the mechanism attribute set of mechanisms described in its specification.
composed by it.
3.3. List of Known Mechanism Attributes 3.2. List of Known Mechanism Attributes
+-------------------------+--------+--------------------------------+ +-------------------------+---------+-------------------------+
| Mech Attr Name | OID | Arc Name | | Mech Attr Name | OID Arc | Arc Name |
| | Arc | | +-------------------------+---------+-------------------------+
+-------------------------+--------+--------------------------------+
| GSS_C_MA_MECH_CONCRETE | (1) | concrete-mech | | GSS_C_MA_MECH_CONCRETE | (1) | concrete-mech |
| GSS_C_MA_MECH_STACKABLE | (2) | pseudo-mech | | GSS_C_MA_MECH_PSEUDO | (2) | pseudo-mech |
| GSS_C_MA_MECH_COMPOSITE | (3) | composite-mech | | GSS_C_MA_MECH_COMPOSITE | (3) | composite-mech |
| GSS_C_MA_MECH_NEGO | (4) | mech-negotiation-mech | | GSS_C_MA_MECH_NEGO | (4) | mech-negotiation-mech |
| GSS_C_MA_MECH_GLUE | (5) | mech-glue | | GSS_C_MA_MECH_GLUE | (5) | mech-glue |
| GSS_C_MA_NOT_MECH | (6) | not-mech | | GSS_C_MA_NOT_MECH | (6) | not-mech |
| GSS_C_MA_DEPRECATED | (7) | mech-deprecated | | GSS_C_MA_DEPRECATED | (7) | mech-deprecated |
| GSS_C_MA_NOT_DFLT_MECH | (8) | mech-not-default | | GSS_C_MA_NOT_DFLT_MECH | (8) | mech-not-default |
| GSS_C_MA_ITOK_FRAMED | (9) | initial-is-framed | | GSS_C_MA_ITOK_FRAMED | (9) | initial-is-framed |
| GSS_C_MA_AUTH_INIT | (10) | auth-init-princ | | GSS_C_MA_AUTH_INIT | (10) | auth-init-princ |
| GSS_C_MA_AUTH_TARG | (11) | auth-targ-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_INIT_INIT | (12) | auth-init-princ-initial |
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| GSS_C_MA_AUTH_TARG_ANON | (15) | auth-targ-princ-anon | | GSS_C_MA_AUTH_TARG_ANON | (15) | auth-targ-princ-anon |
| GSS_C_MA_DELEG_CRED | (16) | deleg-cred | | GSS_C_MA_DELEG_CRED | (16) | deleg-cred |
| GSS_C_MA_INTEG_PROT | (17) | integ-prot | | GSS_C_MA_INTEG_PROT | (17) | integ-prot |
| GSS_C_MA_CONF_PROT | (18) | conf-prot | | GSS_C_MA_CONF_PROT | (18) | conf-prot |
| GSS_C_MA_MIC | (19) | mic | | GSS_C_MA_MIC | (19) | mic |
| GSS_C_MA_WRAP | (20) | wap | | GSS_C_MA_WRAP | (20) | wap |
| GSS_C_MA_PROT_READY | (21) | prot-ready | | GSS_C_MA_PROT_READY | (21) | prot-ready |
| GSS_C_MA_REPLAY_DET | (22) | replay-detection | | GSS_C_MA_REPLAY_DET | (22) | replay-detection |
| GSS_C_MA_OOS_DET | (23) | oos-detection | | GSS_C_MA_OOS_DET | (23) | oos-detection |
| GSS_C_MA_CBINDINGS | (24) | channel-bindings | | GSS_C_MA_CBINDINGS | (24) | channel-bindings |
| GSS_C_MA_CBINDINGS_BIDI | (25) | channel-bindings-bidirectional | | GSS_C_MA_PFS | (25) | pfs |
| GSS_C_MA_CBINDINGS_NEGO | (26) | channel-bindings-negotiate | | GSS_C_MA_COMPRESS | (26) | compress |
| GSS_C_MA_PFS | (27) | pfs | | GSS_C_MA_CTX_TRANS | (27) | context-transfer |
| GSS_C_MA_COMPRESS | (28) | compress | | <reserved> | (28..) | |
| GSS_C_MA_CTX_TRANS | (29) | context-transfer | +-------------------------+---------+-------------------------+
| <reserved> | (30..) | |
+-------------------------+--------+--------------------------------+
Table 1 Table 1
+-------------------------+-----------------------------------------+ +-------------------------+-----------------------------------------+
| Mech Attr Name | Purpose | | Mech Attr Name | Purpose |
+-------------------------+-----------------------------------------+ +-------------------------+-----------------------------------------+
| GSS_C_MA_MECH_CONCRETE | Indicates that a mech is neither a | | GSS_C_MA_MECH_CONCRETE | Indicates that a mech is neither a |
| | pseudo- mechanism nor a composite | | | pseudo- mechanism nor a composite |
| | mechanism. | | | mechanism. |
| GSS_C_MA_MECH_STACKABLE | Indicates that a mech is a | | GSS_C_MA_MECH_PSEUDO | Indicates that a mech is a |
| | pseudo-mechanism. | | | pseudo-mechanism. |
| GSS_C_MA_MECH_COMPOSITE | Indicates that a mech is a composite | | GSS_C_MA_MECH_COMPOSITE | Indicates that a mech is a composite of |
| | mechanism. | | | other mechanisms. This is reserved for |
| | a specification of "stackable" |
| | pseudo-mechanisms. |
| GSS_C_MA_MECH_NEGO | Indicates that a mech negotiates other | | GSS_C_MA_MECH_NEGO | Indicates that a mech negotiates other |
| | mechs (e.g., SPNEGO has this | | | mechs (e.g., SPNEGO has this |
| | attribute). | | | attribute). |
| GSS_C_MA_MECH_GLUE | Indicates that the OID is not for a | | GSS_C_MA_MECH_GLUE | Indicates that the OID is not for a |
| | mechanism but for the GSS-API itself. | | | mechanism but for the GSS-API itself. |
| GSS_C_MA_NOT_MECH | Indicates that the OID is known, yet | | GSS_C_MA_NOT_MECH | Indicates that the OID is known, yet |
| | also known not to be the OID of any | | | also known not to be the OID of any |
| | GSS-API mechanism (or the GSS-API | | | GSS-API mechanism (or the GSS-API |
| | itself). | | | itself). |
| GSS_C_MA_DEPRECATED | Indicates that a mech (or its OID) is | | GSS_C_MA_DEPRECATED | Indicates that a mech (or its OID) is |
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| | default mechanism. | | | default mechanism. |
| GSS_C_MA_NOT_DFLT_MECH | Indicates that a mech (or its OID) MUST | | GSS_C_MA_NOT_DFLT_MECH | Indicates that a mech (or its OID) MUST |
| | NOT be used as a default mechanism. | | | NOT be used as a default mechanism. |
| GSS_C_MA_ITOK_FRAMED | Indicates that the given mechanism's | | GSS_C_MA_ITOK_FRAMED | Indicates that the given mechanism's |
| | initial context tokens are properly | | | initial context tokens are properly |
| | framed as per-section 3.1 of rfc2743. | | | framed as per-section 3.1 of rfc2743. |
| GSS_C_MA_AUTH_INIT | Indicates support for authentication of | | GSS_C_MA_AUTH_INIT | Indicates support for authentication of |
| | initiator to acceptor. | | | initiator to acceptor. |
| GSS_C_MA_AUTH_TARG | Indicates support for authentication of | | GSS_C_MA_AUTH_TARG | Indicates support for authentication of |
| | acceptor to initiator. | | | acceptor to initiator. |
| GSS_C_MA_AUTH_INIT_INIT | Indicates support for initial | | GSS_C_MA_AUTH_INIT_INIT | Indicates support for "initial" |
| | authentication of initiator to | | | authentication of initiator to |
| | acceptor. | | | acceptor. |
| GSS_C_MA_AUTH_TARG_INIT | Indicates support for initial | | GSS_C_MA_AUTH_TARG_INIT | Indicates support for initial |
| | authentication of acceptor to | | | authentication of acceptor to |
| | initiator. | | | initiator. |
| GSS_C_MA_AUTH_INIT_ANON | Indicates support for initiator | | GSS_C_MA_AUTH_INIT_ANON | Indicates support for |
| | anonymity. | | | GSS_C_NT_ANONYMOUS as an initiator |
| GSS_C_MA_AUTH_TARG_ANON | Indicates support for acceptor | | | principal name. |
| | anonymity. | | 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 | | GSS_C_MA_DELEG_CRED | Indicates support for credential |
| | delegation. | | | delegation. |
| GSS_C_MA_INTEG_PROT | Indicates support for per-message | | GSS_C_MA_INTEG_PROT | Indicates support for per-message |
| | integrity protection. | | | integrity protection. |
| GSS_C_MA_CONF_PROT | Indicates support for per-message | | GSS_C_MA_CONF_PROT | Indicates support for per-message |
| | confidentiality protection. | | | confidentiality protection. |
| GSS_C_MA_MIC | Indicates support for MIC tokens. | | GSS_C_MA_MIC | Indicates support for MIC tokens. |
| GSS_C_MA_WRAP | Indicates support for WRAP tokens. | | GSS_C_MA_WRAP | Indicates support for WRAP tokens. |
| GSS_C_MA_PROT_READY | Indicates support for per-message | | GSS_C_MA_PROT_READY | Indicates support for per-message |
| | protection prior to full context | | | protection prior to full context |
| | establishment. | | | establishment. |
| GSS_C_MA_REPLAY_DET | Indicates support for replay detection. | | GSS_C_MA_REPLAY_DET | Indicates support for replay detection. |
| GSS_C_MA_OOS_DET | Indicates support for out-of-sequence | | GSS_C_MA_OOS_DET | Indicates support for out-of-sequence |
| | detection. | | | detection. |
| GSS_C_MA_CBINDINGS | Indicates support for channel bindings. | | GSS_C_MA_CBINDINGS | Indicates support for channel bindings. |
| GSS_C_MA_CBINDINGS_BIDI | Indicates that acceptors |
| | unconditionally indicate to initiators |
| | whether their channel bindings were |
| | matched the acceptors', even when the |
| | acceptor applications use |
| | GSS_C_NO_CHANNEL_BINDINGS.. |
| GSS_C_MA_CBINDINGS_NEGO | Indicates that the mech acts as a |
| | signal for application support for and |
| | willingness to use channel bindings. |
| GSS_C_MA_PFS | Indicates support for Perfect Forward | | GSS_C_MA_PFS | Indicates support for Perfect Forward |
| | Security. | | | Security. |
| GSS_C_MA_COMPRESS | Indicates support for compression of | | GSS_C_MA_COMPRESS | Indicates support for compression of |
| | data inputs to GSS_Wrap(). | | | data inputs to GSS_Wrap(). |
| GSS_C_MA_CTX_TRANS | Indicates support for security context | | GSS_C_MA_CTX_TRANS | Indicates support for security context |
| | export/import. | | | export/import. |
+-------------------------+-----------------------------------------+ +-------------------------+-----------------------------------------+
Table 2 Table 2
3.4. Mechanism Attribute Sets of Existing Mechs 3.3. Mechanism Attribute Sets of Existing Mechs
The Kerberos V mechanism [RFC1964] [CFX] provides the following The Kerberos V mechanism [RFC1964] provides the following mechanism
mechanism attributes: attributes:
o GSS_C_MA_MECH_CONCRETE o GSS_C_MA_MECH_CONCRETE
o GSS_C_MA_ITOK_FRAMED o GSS_C_MA_ITOK_FRAMED
o GSS_C_MA_AUTH_INIT o GSS_C_MA_AUTH_INIT
o GSS_C_MA_AUTH_TARG o GSS_C_MA_AUTH_TARG
o GSS_C_MA_DELEG_CRED o GSS_C_MA_DELEG_CRED
o GSS_C_MA_INTEG_PROT o GSS_C_MA_INTEG_PROT
o GSS_C_MA_CONF_PROT o GSS_C_MA_CONF_PROT
o GSS_C_MA_MIC o GSS_C_MA_MIC
o GSS_C_MA_WRAP o GSS_C_MA_WRAP
o GSS_C_MA_PROT_READY o GSS_C_MA_PROT_READY
o GSS_C_MA_REPLAY_DET o GSS_C_MA_REPLAY_DET
o GSS_C_MA_OOS_DET o GSS_C_MA_OOS_DET
o GSS_C_MA_CBINDINGS o GSS_C_MA_CBINDINGS
o GSS_C_MA_CTX_TRANS (some implementations, using implementation- o GSS_C_MA_CTX_TRANS (some implementations, using implementation-
specific exported context token formats) specific exported context token formats)
The Kerberos V mechanism also has a deprecated OID which has the same The Kerberos V mechanism also has a deprecated OID which has the same
mechanism attributes as above, and GSS_C_MA_DEPRECATED. mechanism attributes as above, and GSS_C_MA_DEPRECATED.
[The mechanism attributes of the SPKM family of mechanisms will be The mechanism attributes of the SPKM [RFC2025] family of mechanisms
provided in a separate document as SPKM is current being reviewed for will be provided in a separate document as SPKM is current being
possibly significant changes due to problems in its specifications.] reviewed for possibly significant changes due to problems in its
specifications.
The LIPKEY mechanism offers the following attributes: The LIPKEY mechanism [RFC2847] offers the following attributes:
o GSS_C_MA_MECH_CONCRETE (should be stackable, but does not compose) o GSS_C_MA_MECH_CONCRETE
o GSS_C_MA_ITOK_FRAMED o GSS_C_MA_ITOK_FRAMED
o GSS_C_MA_AUTH_INIT_INIT o GSS_C_MA_AUTH_INIT_INIT
o GSS_C_MA_AUTH_TARG (from SPKM-3) o GSS_C_MA_AUTH_TARG (from SPKM-3)
o GSS_C_MA_AUTH_TARG_ANON (from SPKM-3) o GSS_C_MA_AUTH_TARG_ANON (from SPKM-3)
o GSS_C_MA_INTEG_PROT o GSS_C_MA_INTEG_PROT
o GSS_C_MA_CONF_PROT o GSS_C_MA_CONF_PROT
o GSS_C_MA_REPLAY_DET o GSS_C_MA_REPLAY_DET
o GSS_C_MA_OOS_DET o GSS_C_MA_OOS_DET
o GSS_C_MA_CTX_TRANS (some implementations, using implementation- o GSS_C_MA_CTX_TRANS (some implementations, using implementation-
specific exported context token formats) specific exported context token formats)
(LIPKEY should also provide GSS_C_MA_CBINDINGS, but SPKM-3 (LIPKEY should also provide GSS_C_MA_CBINDINGS, but SPKM-3
requires clarifications on this point.) requires clarifications on this point.)
The SPNEGO mechanism [SPNEGO] provides the following attributes: The SPNEGO mechanism [RFC4178] provides the following attributes:
o GSS_C_MA_MECH_NEGO o GSS_C_MA_MECH_NEGO
o GSS_C_MA_ITOK_FRAMED o GSS_C_MA_ITOK_FRAMED
The attributes of mechanisms negotiated by SPNEGO are not modified by The attributes of mechanisms negotiated by SPNEGO are not modified by
the use of SPNEGO. the use of SPNEGO.
All other mechanisms' attributes will be described elsewhere. All other mechanisms' attributes will be described elsewhere.
3.5. New GSS-API Function Interfaces 3.4. New GSS-API Function Interfaces
Several new interfaces are given by which, for example, GSS-API Several new interfaces are given by which, for example, GSS-API
applications may determine what features are provided by a given applications may determine what features are provided by a given
mechanism, what mechanisms provide what features and what mechanism and what mechanisms provide what features.
compositions are legal.
These new interfaces are all OPTIONAL. These new interfaces are all OPTIONAL.
In order to preserve backwards compatibility with applications that Applications should use GSS_Indicate_mechs_by_attr() instead of
do not use the new interfaces GSS_Indicate_mechs() MUST NOT indicate
support for any stackable pseduo-mechanisms. GSS_Indicate_mechs()
MAY indicate support for some, all or none of the available composite
mechanisms; which composite mechanisms, if any, are indicated through
GSS_Indicate_mechs() SHOULD be configurable. GSS_Acquire_cred() and
GSS_Add_cred() MUST NOT create credentials for composite mechanisms
not explicitly requested or, if no desired mechanism or mechanisms
are given, for composite mechanisms not indicated by
GSS_Indicate_mechs().
Applications SHOULD use GSS_Indicate_mechs_by_attr() instead of
GSS_Indicate_mechs() wherever possible. GSS_Indicate_mechs() wherever possible.
Applications can use GSS_Indicate_mechs_by_attr() to determine what, Applications can use GSS_Indicate_mechs_by_attr() to determine what,
if any, mechanisms provide a given set of features. if any, mechanisms provide a given set of features.
GSS_Indicate_mechs_by_attr() can also be used to indicate (as in GSS_Indicate_mechs_by_attr() can also be used to indicate (as in
GSS_Indicate_mechs()) the set of available mechanisms of each type GSS_Indicate_mechs()) the set of available mechanisms of each type
(concrete, mechanism negotiation pseudo-mechanism, stackable pseudo- (concrete, mechanism negotiation pseudo-mechanism, etc.).
mechanism and composite mechanisms).
Applications may use GSS_Inquire_attrs_for_mech() to test whether a
given composite mechanism is available and the set of features that
it offers.
3.5.1. GSS_Indicate_mechs_by_attr()
3.4.1. GSS_Indicate_mechs_by_attr()
Inputs: Inputs:
o desired_mech_attrs SET OF OBJECT IDENTIFIER -- set of GSS_C_MA_* o desired_mech_attrs SET OF OBJECT IDENTIFIER -- set of GSS_C_MA_*
OIDs that the mechanisms indicated in the mechs output parameter OIDs that the mechanisms indicated in the mechs output parameter
MUST offer. MUST offer.
o except_mech_attrs SET OF OBJECT IDENTIFIER -- set of GSS_C_MA_* o except_mech_attrs SET OF OBJECT IDENTIFIER -- set of GSS_C_MA_*
OIDs that the mechanisms indicated in the mechs output parameter OIDs that the mechanisms indicated in the mechs output parameter
MUST NOT offer. MUST NOT offer.
Outputs: Outputs:
o major_status INTEGER, o major_status INTEGER,
skipping to change at page 9, line 25 skipping to change at page 8, line 36
GSS_Indicate_mechs_by_mech_attrs() returns the set of mechanism OIDs GSS_Indicate_mechs_by_mech_attrs() returns the set of mechanism OIDs
that offer at least the desired_mech_attrs but none of the that offer at least the desired_mech_attrs but none of the
except_mech_attrs. except_mech_attrs.
When desired_mech_attrs and except_mech_attrs are the empty set this When desired_mech_attrs and except_mech_attrs are the empty set this
function acts as a version of GSS_indicate_mechs() that outputs the function acts as a version of GSS_indicate_mechs() that outputs the
set of all supported mechanisms of all types. By setting the set of all supported mechanisms of all types. By setting the
desired_mechs input parameter to a set of a single GSS_C_MA_MECH* desired_mechs input parameter to a set of a single GSS_C_MA_MECH*
feature applications can obtain the list of all supported mechanisms feature applications can obtain the list of all supported mechanisms
of a given type (concrete, stackable, etc...). of a given type (concrete, etc...).
3.5.2. GSS_Inquire_attrs_for_mech() 3.4.2. GSS_Inquire_attrs_for_mech()
Inputs: Inputs:
o mech OBJECT IDENTIFIER -- mechanism OID o mech OBJECT IDENTIFIER -- mechanism OID
Outputs: Outputs:
o major_status INTEGER, o major_status INTEGER,
o minor_status INTEGER, o minor_status INTEGER,
o mech_attrs SET OF OBJECT IDENTIFIER -- set of mech_attrs OIDs o mech_attrs SET OF OBJECT IDENTIFIER -- set of mech_attrs OIDs
(GSS_C_MA_*) (GSS_C_MA_*)
skipping to change at page 9, line 41 skipping to change at page 9, line 4
Outputs: Outputs:
o major_status INTEGER, o major_status INTEGER,
o minor_status INTEGER, o minor_status INTEGER,
o mech_attrs SET OF OBJECT IDENTIFIER -- set of mech_attrs OIDs o mech_attrs SET OF OBJECT IDENTIFIER -- set of mech_attrs OIDs
(GSS_C_MA_*) (GSS_C_MA_*)
Return major_status codes: Return major_status codes:
o GSS_S_COMPLETE indicates success; the output mech_attrs parameter o GSS_S_COMPLETE indicates success; the output mech_attrs parameter
MAY be the empty set (GSS_C_NO_OID_SET). MAY be the empty set (GSS_C_NO_OID_SET).
o GSS_S_BAD_MECH indicates that the mechanism named by the mech o GSS_S_BAD_MECH indicates that the mechanism named by the mech
parameter does not exist or that mech is GSS_C_NO_OID and no parameter does not exist or that mech is GSS_C_NO_OID and no
default mechanism could be determined. default mechanism could be determined.
o GSS_S_FAILURE indicates that the request failed for some other o GSS_S_FAILURE indicates that the request failed for some other
reason. reason.
GSS_Inquire_mech_attrs_for_mech() indicates the set of mechanism GSS_Inquire_mech_attrs_for_mech() indicates the set of mechanism
attributes supported by a given mechanism. attributes supported by a given mechanism.
Because the mechanism attribute sets of composite mechanisms need not 3.4.3. GSS_Display_mech_attr()
be the union of their components', when called to obtain the feature
set of a composite mechanism GSS_Inquire_mech_attrs_for_mech()
obtains it by querying the mechanism at the top of the stack. See
Section 3.1.
3.5.3. GSS_Display_mech_attr()
Inputs: Inputs:
o mech_attr OBJECT IDENTIFIER -- mechanism attribute OID o mech_attr OBJECT IDENTIFIER -- mechanism attribute OID
Outputs: Outputs:
o major_status INTEGER, o major_status INTEGER,
o minor_status INTEGER, o minor_status INTEGER,
o name OCTET STRING, -- name of mechanism attribute (e.g., o name OCTET STRING, -- name of mechanism attribute (e.g.,
GSS_C_MA_*) GSS_C_MA_*)
o short_desc OCTET STRING, -- a short description of the mechanism o short_desc OCTET STRING, -- a short description of the mechanism
skipping to change at page 10, line 34 skipping to change at page 9, line 40
o GSS_S_COMPLETE indicates success. o GSS_S_COMPLETE indicates success.
o GSS_S_BAD_MECH_ATTR indicates that the mechanism attribute o GSS_S_BAD_MECH_ATTR indicates that the mechanism attribute
referenced by the mech_attr parameter is unknown to the referenced by the mech_attr parameter is unknown to the
implementation. implementation.
o GSS_S_FAILURE indicates that the request failed for some other o GSS_S_FAILURE indicates that the request failed for some other
reason. reason.
This function can be used to obtain human-readable descriptions of This function can be used to obtain human-readable descriptions of
GSS-API mechanism attributes. GSS-API mechanism attributes.
3.5.4. New Major Status Values 3.4.4. New Major Status Values
A single new major status code is added for GSS_Display_mech_attr(): A single new major status code is added for GSS_Display_mech_attr():
o GSS_S_BAD_MECH_ATTR o GSS_S_BAD_MECH_ATTR
roughly corresponding to GSS_S_BAD_MECH, but applicable to mechanism roughly corresponding to GSS_S_BAD_MECH, but applicable to mechanism
attribute OIDs, rather than to mechanism OIDs. attribute OIDs, rather than to mechanism OIDs.
For the C-bindings GSS_S_BAD_MECH_ATTR shall have a routine error For the C-bindings of the GSS-API [RFC2744] GSS_S_BAD_MECH_ATTR shall
number of 19 (this is shifted to the left by have a routine error number of 19 (this is shifted to the left by
GSS_C_ROUTINE_ERROR_OFFSET). GSS_C_ROUTINE_ERROR_OFFSET).
3.5.5. C-Bindings 3.4.5. C-Bindings
#define GSS_S_BAD_MECH_ATTR (19ul << GSS_C_ROUTINE_ERROR_OFFSET) #define GSS_S_BAD_MECH_ATTR (19ul << GSS_C_ROUTINE_ERROR_OFFSET)
OM_uint32 gss_inquire_mechs_for_mech_attrs( OM_uint32 gss_inquire_mechs_for_mech_attrs(
OM_uint32 *minor_status, OM_uint32 *minor_status,
const gss_OID_set desired_mech_attrs, const gss_OID_set desired_mech_attrs,
gss_OID_set *mechs); gss_OID_set *mechs);
OM_uint32 gss_inquire_mech_attrs_for_mech( OM_uint32 gss_inquire_mech_attrs_for_mech(
OM_uint32 *minor_status, OM_uint32 *minor_status,
const gss_OID mech, const gss_OID mech,
skipping to change at page 11, line 23 skipping to change at page 10, line 27
OM_uint32 *minor_status, OM_uint32 *minor_status,
const gss_OID mech_attr, const gss_OID mech_attr,
gss_buffer_t name, gss_buffer_t name,
gss_buffer_t short_desc, gss_buffer_t short_desc,
gss_buffer_t long_desc); gss_buffer_t long_desc);
Figure 1 Figure 1
4. Requirements for Mechanism Designers 4. Requirements for Mechanism Designers
Stackable pseudo-mechanisms specifications MUST: All future GSS-API mechanism specifications MUST:
o list the set of GSS-API mechanism attributes associated with them
o list their initial mechanism composition rules
o specify a mechanism for updating their mechanism composition rules
All other mechanism specifications MUST:
o list the set of GSS-API mechanism attributes associated with them o list the set of GSS-API mechanism attributes associated with them
5. IANA Considerations 5. IANA Considerations
The namsepace of programming language symbols with names beginning The namsepace of programming language symbols with names beginning
with GSS_C_MA_* is reserved for allocation by the IANA. with GSS_C_MA_* is reserved for allocation by IESG Protocol Action
(probably in the specifications of future GSS-API mechanisms).
Allocation of arcs in the namespace of OIDs relative to the base
mechanism attribute OID specified in Section 3.1 is reserved to the
IANA.
6. Security considerations 6. Security considerations
... This document specifies extensions to a security-related API. It
imposes new requirements on future GSS-API mechanisms, and the
specification 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.
7. References 7. References
7.1. Normative 7.1. Normative References
[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.
[RFC2743] Linn, J., "Generic Security Service Application Program [RFC2743] Linn, J., "Generic Security Service Application Program
Interface Version 2, Update 1", RFC 2743, January 2000. Interface Version 2, Update 1", RFC 2743, January 2000.
[RFC2744] Wray, J., "Generic Security Service API Version 2 : [RFC2744] Wray, J., "Generic Security Service API Version 2 :
C-bindings", RFC 2744, January 2000. C-bindings", RFC 2744, January 2000.
7.2. Normative 7.2. Informative References
[RFC1964] Linn, J., "The Kerberos Version 5 GSS-API Mechanism", [RFC1964] Linn, J., "The Kerberos Version 5 GSS-API Mechanism",
RFC 1964, June 1996. RFC 1964, June 1996.
[RFC2478] Baize, E. and D. Pinkas, "The Simple and Protected GSS-API [RFC2025] Adams, C., "The Simple Public-Key GSS-API Mechanism
Negotiation Mechanism", RFC 2478, December 1998. (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.
Author's Address Author's Address
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
Intellectual Property Statement Full Copyright Statement
Copyright (C) The IETF Trust (2008).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Intellectual Property
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
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on the procedures with respect to rights in RFC documents can be on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79. found in BCP 78 and BCP 79.
skipping to change at page 14, line 29 skipping to change at page 12, line 45
such proprietary rights by implementers or users of this such proprietary rights by implementers or users of this
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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
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Disclaimer of Validity
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Copyright Statement
Copyright (C) The Internet Society (2006). This document is subject
to the rights, licenses and restrictions contained in BCP 78, and
except as set forth therein, the authors retain all their rights.
Acknowledgment Acknowledgment
Funding for the RFC Editor function is currently provided by the Funding for the RFC Editor function is provided by the IETF
Internet Society. Administrative Support Activity (IASA).
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