draft-ietf-abfab-gss-eap-naming-04.txt   draft-ietf-abfab-gss-eap-naming-05.txt 
Network Working Group S. Hartman Network Working Group S. Hartman
Internet-Draft Painless Security Internet-Draft Painless Security
Intended status: Standards Track J. Howlett Intended status: Standards Track J. Howlett
Expires: February 15, 2013 JANET(UK) Expires: March 23, 2013 JANET(UK)
August 14, 2012 September 19, 2012
Name Attributes for the GSS-API EAP mechanism Name Attributes for the GSS-API EAP mechanism
draft-ietf-abfab-gss-eap-naming-04 draft-ietf-abfab-gss-eap-naming-05
Abstract Abstract
The naming extensions to the Generic Security Services Application The naming extensions to the Generic Security Services Application
Programming interface provide a mechanism for applications to Programming interface provide a mechanism for applications to
discover authorization and personalization information associated discover authorization and personalization information associated
with GSS-API names. The Extensible Authentication Protocol GSS-API with GSS-API names. The Extensible Authentication Protocol GSS-API
mechanism allows an Authentication/Authorization/Accounting peer to mechanism allows an Authentication/Authorization/Accounting peer to
provide authorization attributes along side an authentication provide authorization attributes along side an authentication
response. It also provides mechanisms to process Security Assertion response. It also provides mechanisms to process Security Assertion
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This Internet-Draft will expire on February 15, 2013. This Internet-Draft will expire on March 23, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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publication of this document. Please review these documents publication of this document. Please review these documents
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include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements notation . . . . . . . . . . . . . . . . . . . . 4 2. Requirements notation . . . . . . . . . . . . . . . . . . . . 4
3. Naming Extensions and SAML . . . . . . . . . . . . . . . . . . 5 3. Naming Extensions and SAML . . . . . . . . . . . . . . . . . . 5
4. Federated Context . . . . . . . . . . . . . . . . . . . . . . 6 4. Federated Context . . . . . . . . . . . . . . . . . . . . . . 6
5. Name Attributes for GSS-EAP . . . . . . . . . . . . . . . . . 7 5. Name Attributes for GSS-EAP . . . . . . . . . . . . . . . . . 8
6. Names of SAML Attributes in the Federated Context . . . . . . 8 6. Names of SAML Attributes in the Federated Context . . . . . . 9
6.1. Assertions . . . . . . . . . . . . . . . . . . . . . . . . 8 6.1. Assertions . . . . . . . . . . . . . . . . . . . . . . . . 9
6.2. SAML Attributes . . . . . . . . . . . . . . . . . . . . . 8 6.2. SAML Attributes . . . . . . . . . . . . . . . . . . . . . 9
6.3. SAML Name Identifiers . . . . . . . . . . . . . . . . . . 8 6.3. SAML Name Identifiers . . . . . . . . . . . . . . . . . . 10
7. Security Considerations . . . . . . . . . . . . . . . . . . . 10 7. Security Considerations . . . . . . . . . . . . . . . . . . . 11
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
8.1. Registration of the GSS URN Namespace . . . . . . . . . . 11 8.1. Registration of the GSS URN Namespace . . . . . . . . . . 12
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
10.1. Normative References . . . . . . . . . . . . . . . . . . . 13 10.1. Normative References . . . . . . . . . . . . . . . . . . . 14
10.2. Informative References . . . . . . . . . . . . . . . . . . 13 10.2. Informative References . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction 1. Introduction
The naming extensions [I-D.ietf-kitten-gssapi-naming-exts]to the The naming extensions [I-D.ietf-kitten-gssapi-naming-exts]to the
Generic Security Services Application Programming interface (GSS-API) Generic Security Services Application Programming interface (GSS-API)
[RFC2743] provide a mechanism for applications to discover [RFC2743] provide a mechanism for applications to discover
authorization and personalization information associated with GSS-API authorization and personalization information associated with GSS-API
names. The Extensible Authentication Protocol GSS-API mechanism names. The Extensible Authentication Protocol GSS-API mechanism
[I-D.ietf-abfab-gss-eap] allows an Authentication/Authorization/ [I-D.ietf-abfab-gss-eap] allows an Authentication/Authorization/
Accounting peer to provide authorization attributes along side an Accounting peer to provide authorization attributes along side an
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the SAML assertion also comes from the party performing the SAML assertion also comes from the party performing
authentication. Typically, the IDP is run by another organization in authentication. Typically, the IDP is run by another organization in
the same federation. The IDP is trusted to make some statements, the same federation. The IDP is trusted to make some statements,
particularly related to the context of a federation. For example, an particularly related to the context of a federation. For example, an
academic federation's participants would typically trust an IDP's academic federation's participants would typically trust an IDP's
assertions about whether someone was a student or a professor. assertions about whether someone was a student or a professor.
However that same IDP would not typically be trusted to make However that same IDP would not typically be trusted to make
assertions about local entitlements such as group membership. Thus, assertions about local entitlements such as group membership. Thus,
a service MUST make a policy decision about whether the IDP is a service MUST make a policy decision about whether the IDP is
permitted to assert a particular attribute and about whether the permitted to assert a particular attribute and about whether the
asserted value is acceptable. asserted value is acceptable. This policy can be implemented as
local configuration on the service, as rules in AAA proxies, or
through other deployment-specific mechanisms.
In contrast, attributes in an enterprise context are often verified In contrast, attributes in an enterprise context are often verified
by a central authentication infrastructure that is trusted to assert by a central authentication infrastructure that is trusted to assert
most or all attributes. For example, in a Kerberos infrastructure, most or all attributes. For example, in a Kerberos infrastructure,
the KDC typically indicates group membership information for clients the KDC typically indicates group membership information for clients
to a server using KDC-authenticated authorization data. to a server using KDC-authenticated authorization data.
The context of an attribute is an important property of that The context of an attribute is an important property of that
attribute; trust context is an important part of this overall attribute; trust context is an important part of this overall
context. In order for applications to distinguish the context of context. In order for applications to distinguish the context of
attributes, attributes with different context need different names. attributes, attributes with different context need different names.
This specification defines attribute names for SAML and AAA This specification defines attribute names for SAML and AAA
attributes in the federated context. attributes in the federated context.
These names MUST NOT be used for attributes issued by a party other These names MUST NOT be used for attributes issued by a party other
than one closely associated with the source of credentials unless the than one closely associated with the source of credentials unless the
source of credentials is re-asserting the attributes. For example, a source of credentials is re-asserting the attributes. For example, a
source of credentials can consult whatever sources of attributes it source of credentials can consult whatever sources of attributes it
chooses, but acceptors can assume attributes in the federated context chooses, but acceptors can assume attributes in the federated context
are from the source of credentials. are from the source of credentials. This requirement is typically
enforced in mechanism specifications. For example
[I-D.ietf-abfab-aaa-saml] provides enough information thatwe know the
attributes it carries today are in the federated context. Similarly,
we know that the requirements of this paragraph are met by SAML
mechanisms where the assertion is the means of authentication.
5. Name Attributes for GSS-EAP 5. Name Attributes for GSS-EAP
This section describes how RADIUS attributes received in an access- This section describes how RADIUS attributes received in an access-
accept message by the GSS-EAP [I-D.ietf-abfab-gss-eap] mechanism are accept message by the GSS-EAP [I-D.ietf-abfab-gss-eap] mechanism are
named. The use of attributes defined in this section for other named. The use of attributes defined in this section for other
RADIUS messages or prior to the access-accept message is undefined at RADIUS messages or prior to the access-accept message is undefined at
this time. Future specifations can explore these areas giving this time. Future specifations can explore these areas giving
adequate weight to backward compatibility. adequate weight to backward compatibility. In particular, this
specification defines the meaning of these attributes for the
src_name output of GSS_Accept_sec_context after that function returns
GSS_S_COMPLETE. Attributes MAy be absent or values MAY change in
other circumstances; future specifications MAY define this behavior.
The first portion of the name is urn:ietf:params:gss:radius-attribute The first portion of the name is urn:ietf:params:gss:radius-attribute
(a URN indicating that this is a GSS-EAP RADIUS AVP). This is (a URN indicating that this is a GSS-EAP RADIUS AVP). This is
followed by a space and a numeric RADIUS name as described by section followed by a space and a numeric RADIUS name as described by section
2.6 of [I-D.ietf-radext-radius-extensions]. For example the name of 2.6 of [I-D.ietf-radext-radius-extensions]. For example the name of
the User-Name attribute is "urn:ietf:gss:radius-attribute 1". The the User-Name attribute is "urn:ietf:params:gss:radius-attribute 1".
name of extended type 1 within type 241 would be The name of extended type 1 within type 241 would be
"urn:ietf:gss:radius-attribute 241.1". "urn:ietf:params:gss:radius-attribute 241.1".
Consider a case where the RADIUS access-accept response includes the
RADIUS username attribute. An application wishing to retrieve the
value of this attribute would first wait until GSS-
_Accept_sec_Context returned GSS_S_COMPLETE. Then the application
would take the src_name output from GSS_Accept_Sec_context and call
GSS_Get_Name_attribute passing this name and an attribute of
"urn:ietf:params:gss:radius-attribute 1" as inputs. After confirming
that the authenticated boolean output is true, the application can
find the username in the values output.
The value of RADIUS attributes is the raw octets of the packet. The value of RADIUS attributes is the raw octets of the packet.
Integers are in network byte order. The display value SHOULD be a Integers are in network byte order. The display value SHOULD be a
human readable string; an implementation can only produce this string human readable string; an implementation can only produce this string
if it knows the type of a given RADIUS attribute. If multiple if it knows the type of a given RADIUS attribute. If multiple
attributes are present with a given name in the RADIUS message, then attributes are present with a given name in the RADIUS message, then
a multi-valued GSS-API attribute SHOULD be returned. As an a multi-valued GSS-API attribute SHOULD be returned. As an
exception, implementations SHOULD concatenate RADIUS attributes such exception, implementations SHOULD concatenate RADIUS attributes such
as EAP-Message or large attributes defined in as EAP-Message or large attributes defined in
[I-D.ietf-radext-radius-extensions] that use multiple attributes to [I-D.ietf-radext-radius-extensions] that use multiple attributes to
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6. Names of SAML Attributes in the Federated Context 6. Names of SAML Attributes in the Federated Context
6.1. Assertions 6.1. Assertions
An assertion generated by the credential source is named by An assertion generated by the credential source is named by
"urn:ietf:params:gss:federated-saml-assertion". The value of this "urn:ietf:params:gss:federated-saml-assertion". The value of this
attribute is the assertion carried in the AAA protocol or used for attribute is the assertion carried in the AAA protocol or used for
authentication in a SAML mechanism. This attribute is absent from a authentication in a SAML mechanism. This attribute is absent from a
given acceptor name if no such assertion is present or if the given acceptor name if no such assertion is present or if the
assertion fails local policy checks. This attribute is always assertion fails local policy checks.
authenticated when present in mechanism names for mechanisms
complying with this specification: authentication only succeeds if This attribute is returned with the authenticatedoutput of
the SAML or AAA exchange is successfully authenticated. However, GSS_Get_name_attribute true only when the mechanism can successfully
users of the GSS-API MUST confirm that the attribute is authenticated authenticated the SAML statement. For the GSS-EAP mechanism this is
because some other mechanisms MAY permit an initiator to assert an true if the AAA exchange has successfully authenticated. However,
unauthenticated version of this attribute. uses of the GSS-API MUST confirm that the attribute is marked
authenticated as other mechanisms MAY permit an initiator to provide
an unauthenticated SAML statement.
Mechanisms MAY perform additional local policy checks and MAY remove
the attribute corresponding to assertions that fail these checks.
6.2. SAML Attributes 6.2. SAML Attributes
Each attribute carried in the assertion SHOULD also be a GSS name Each attribute carried in the assertion SHOULD also be a GSS name
attribute. The name of this attribute has three parts, all separated attribute. The name of this attribute has three parts, all separated
by an ASCII space character. The first part is by an ASCII space character. The first part is
urn:ietf:params:gss:federated-saml-attribute. The second part is the urn:ietf:params:gss:federated-saml-attribute. The second part is the
URI for the <saml:Attribute> element's NameFormat XML attribute. The URI for the <saml:Attribute> element's NameFormat XML attribute. The
final part is the <saml:Attribute> element's Name XML attribute. final part is the <saml:Attribute> element's Name XML attribute. The
SAML attribute name may itself contain spaces. As required by the
URI specification, spaces within a URI are encoded as "%20". Spaces
within a URI, including either the first or second part of the name,
encoding as "%20" do not separate parts of the GSS-API attribute
name; they are simply part of the URI.
As an example, if the eduPersonEntitlement attribute is present in an
assertion, then An attribute with the name
"urn:ietf:params:gss:federated-saml-attribute
urn:oasis:names:tc:SAML:2.0:attrname-format:uri
urn:oid:1.3.6.1.4.1.5923.1.1.1.7 " could be returned from
GSS_Inquire_Name. If an application calls GSS_Get_Name_attribute
with this attribute in the attr parameter then the values output
would include one or more URIs of entitlements that were associated
with the authenticated user.
If the content of each <saml:AttributeValue> element is a simple text If the content of each <saml:AttributeValue> element is a simple text
node (or nodes), then the raw and "display" values of the GSS name node (or nodes), then the raw and "display" values of the GSS name
attribute MUST be the text content of the element(s). The raw value attribute MUST be the text content of the element(s). The raw value
MUST be encoded as UTF-8. MUST be encoded as UTF-8.
If the value is not simple or is empty, then the raw value(s) of the If the value is not simple or is empty, then the raw value(s) of the
GSS name attribute MUST be the well-formed serialization of the GSS name attribute MUST be the well-formed serialization of the
<saml:AttributeValue> element(s) encoded as UTF-8. The "display" <saml:AttributeValue> element(s) encoded as UTF-8. The "display"
values are implementation-defined. values are implementation-defined.
These attributes SHOULD be marked authenticated if they are contained These attributes SHOULD be marked authenticated if they are contained
in SAML assertions that have been successfully validated back to the in SAML assertions that have been successfully validated back to the
trusted source of the peer credential. In the GSS-EAP mechanism, a trusted source of the peer credential. In the GSS-EAP mechanism, a
SAML assertion carried in an integrity-protected and authenticated SAML assertion carried in an integrity-protected and authenticated
AAA protocol SHALL be sufficiently validated. An implementation MAY AAA protocol SHALL be successfully validated; attributes from that
apply local policy checks to this assertion and discard it if it is assertion SHALL be returned from GSS_Get_Name_attribute with the
unacceptable according to these checks. authenticated output set to true. An implementation MAY apply local
policy checks to each attribute in this assertion and discard the
attribute if it is unacceptable according to these checks.
6.3. SAML Name Identifiers 6.3. SAML Name Identifiers
The <saml:NameID> carried in the subject of the assertion SHOULD also The <saml:NameID> carried in the subject of the assertion SHOULD also
be a GSS name attribute. The name of this attribute has two parts, be a GSS name attribute. The name of this attribute has two parts,
separated by an ASCII space character. The first part is separated by an ASCII space character. The first part is
urn:ietf:params:gss:federated-saml-nameid. The second part is the urn:ietf:params:gss:federated-saml-nameid. The second part is the
URI for the <saml:NameID> element's Format XML attribute. URI for the <saml:NameID> element's Format XML attribute.
The raw value of the GSS name attribute MUST be the well-formed The raw value of the GSS name attribute MUST be the well-formed
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attributes defined in this document. If there is another way to get attributes defined in this document. If there is another way to get
access to the SAML assertion, for example the mechanism described in access to the SAML assertion, for example the mechanism described in
[I-D.ietf-abfab-aaa-saml], then an application MAY get different [I-D.ietf-abfab-aaa-saml], then an application MAY get different
results depending on how the SAML is accessed. This is intended results depending on how the SAML is accessed. This is intended
behavior; applications who choose to bypass local policy checks behavior; applications who choose to bypass local policy checks
SHOULD perform their own evaluation before relying on information. SHOULD perform their own evaluation before relying on information.
8. IANA Considerations 8. IANA Considerations
A new top-level registry is created titled "Generic Security Service A new top-level registry is created titled "Generic Security Service
Application Program Interface Parameters". There doesn't seem to be Application Program Interface Parameters".
an existing top-level registry that can be used. There are
Parameters for the Kerberos V mechanism; parameters for the GSS-API
EAP mechanism; and GSS-API/SASL/Kerberos service names. However none
of these are the right place.
In this top-level registry, a sub-registry titled "GSS-API URN In this top-level registry, a sub-registry titled "GSS-API URN
Parameters" is created. Registration in this registry is by the IETF Parameters" is created. Registration in this registry is by the IETF
review or expert review procedures [RFC5226]. Registrations in this review or expert review procedures [RFC5226]. Registrations in this
registry are generally only expected as part of protocols published registry are generally only expected as part of protocols published
as RFCs on the IETF stream; other URIs are expected to be better as RFCs on the IETF stream; other URIs are expected to be better
choices for non-IETf work. Expert review is permitted mainly to choices for non-IETf work. Expert review is permitted mainly to
permit early registration related to specifications under development permit early registration related to specifications under development
when the community believes they have reach sufficient maturity. when the community believes they have reach sufficient maturity.
If the "paramname" parameter is registered in this registry then its If the "paramname" parameter is registered in this registry then its
URN will be "urn:ietf:gss:paramname". The initial registrations are URN will be "urn:ietf:params:gss:paramname". The initial
as follows: registrations are as follows:
+--------------------------+-------------+ +--------------------------+-------------+
| Parameter | Reference | | Parameter | Reference |
+--------------------------+-------------+ +--------------------------+-------------+
| radius-attribute | Section 5 | | radius-attribute | Section 5 |
| | | | | |
| federated-saml-assertion | Section 6.1 | | federated-saml-assertion | Section 6.1 |
| | | | | |
| federated-saml-attribute | Section 6.2 | | federated-saml-attribute | Section 6.2 |
| | | | | |
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10.2. Informative References 10.2. Informative References
[I-D.ietf-abfab-aaa-saml] [I-D.ietf-abfab-aaa-saml]
Howlett, J. and S. Hartman, "A RADIUS Attribute, Binding Howlett, J. and S. Hartman, "A RADIUS Attribute, Binding
and Profiles for SAML", draft-ietf-abfab-aaa-saml-03 (work and Profiles for SAML", draft-ietf-abfab-aaa-saml-03 (work
in progress), March 2012. in progress), March 2012.
[I-D.ietf-kitten-sasl-saml-ec] [I-D.ietf-kitten-sasl-saml-ec]
Cantor, S. and S. Josefsson, "SAML Enhanced Client SASL Cantor, S. and S. Josefsson, "SAML Enhanced Client SASL
and GSS-API Mechanisms", draft-ietf-kitten-sasl-saml-ec-02 and GSS-API Mechanisms", draft-ietf-kitten-sasl-saml-ec-03
(work in progress), August 2012. (work in progress), September 2012.
Authors' Addresses Authors' Addresses
Sam Hartman Sam Hartman
Painless Security Painless Security
Email: hartmans-ietf@mit.edu Email: hartmans-ietf@mit.edu
Josh Howlett Josh Howlett
JANET(UK) JANET(UK)
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