One document matched: draft-ietf-abfab-gss-eap-naming-01.xml

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<rfc category="std" ipr="trust200902" docName="draft-ietf-abfab-gss-eap-naming-01">

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  <front>
    <title abbrev="GSS EAP Name Attributes">Name Attributes for the GSS-API EAP mechanism</title>
        <author initials="S." surname="Hartman" fullname="Sam Hartman" >
      <organization>Painless Security</organization>
      <address>
	<email>hartmans-ietf@mit.edu</email>
      </address>
    </author>    <author initials="J." surname="Howlett" fullname="Josh Howlett">
      <organization>JANET(UK)</organization>
      <address>
	<email>josh.howlett@ja.net</email>
      </address>
    </author>


    <date/>
    <abstract>
      <t>The naming extensions to the Generic Security Services Application Programming interface provide a mechanism for applications to discover authorization and personalization information associated with GSS-API names. The Extensible Authentication Protocol GSS-API mechanism allows an Authentication/Authorization/Accounting peer to provide authorization attributes along side an authentication response. It also provides mechanisms to process Security Assertion Markup Language (SAML) messages provided in the AAA response. This document describes the necessary information to use the naming extensions API to access that information.</t>
    </abstract>
  </front>

    <middle>
    <section title="Introduction">
      <t>The naming extensions <xref
      target="I-D.ietf-kitten-gssapi-naming-exts"/>to the Generic Security Services
      Application Programming interface (GSS-API) <xref target="RFC2743"/> provide a mechanism for
      applications to discover authorization and personalization
      information associated with GSS-API names. The Extensible
      Authentication Protocol GSS-API mechanism <xref
      target="I-D.ietf-abfab-gss-eap"/> allows an
      Authentication/Authorization/Accounting peer to provide
      authorization attributes along side an authentication
      response. It also provides mechanisms to process Security
      Assertion Markup Language (SAML) messages provided in the AAA
      response. Other mechanisms such as SAML EC <xref target="I-D.ietf-kitten-sasl-saml-ec"/> also support SAML assertions and attributes carried in the GSS-API. This document describes the necessary information to
      use the naming extensions API to access SAML assertions in the federated context and AAA attributes.</t> 
    </section>
        <section title="Requirements notation">
            <t>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 <xref target="RFC2119"/>.</t>
        </section>
    <section title="Naming Extensions and SAML">
      <t>SAML assertions can carry attributes describing properties of
      the subject of the assertion. For example, an assertion might
      carry an attribute describing the organizational affiliation or
      e-mail address of a subject. According to Section 8.2 and
      2.7.3.1 of [SAMLCORE],
      the name of an attribute has two parts. The first is a URI
      describing the format of the name. The second part, whose form
      depends on the format URI, is the actual name. GSS-API name attributes may take a form starting with a URI describing the form of the name; the rest of the name is specified by that URI. </t>
      <t>SAML attributes carried in GSS-API names are named with three parts. The first is a URN indicating that the name is a SAML attribute and describing the context (<xref target="FED.CONTEXT"/>). This URI is followed by a space, the  URI indicating the format of the SAML name, a space and the SAML attribute name. The URI indicating the format of the SAML attribute name is not optional and MUST be present.</t>
      <t>SAML attribute names may not be globally unique. Many names that are named by URNs or URIs are likely to have semantics independent of the issuer. However for other name formats, including unspecified name formats, make it easy for two issuers to choose the same name for attributes with different semantics. Attributes using  the federated context <xref target="FED.CONTEXT"/> are issued by the same party performing the authentication. So, based on who is named by the name, the semantics of the attribute can be determined.</t>
    </section>
    <section anchor="FED.CONTEXT" title="Federated Context">
      <t>GSS-API naming extensions have the concept of an
      authenticated name attribute. The mechanism guarantees that the
      contents of an authenticated name attribute are an authenticated
      statement from the trusted source of the peer credential. The fact
      that an attribute is authenticated does not imply that the
      trusted source of the peer credential is authorized to assert
      the attribute.</t>
      <t>In the federated context, the trusted source of the peer
      credential is typically some identity provider. In the GSS EAP
      mechanism, information is combined from AAA and SAML
      sources. The SAML IDP and home AAA server are assumed to be in
      the same trust domain. However, this trust domain is not
      typically the same as the trust domain of the service. With other SAML mechanisms using this specification, the SAML assertion also comes from the party performing authentication. Typically, the IDP is run by another organization in the same federation. The IDP is trusted to make some statements, particularly related to the context of a federation. For example, an academic federation's participants would typically trust an IDP's assertions about whether someone was a student or a professor. However that same IDP would not typically be trusted to make assertions about local entitlements such as group membership. Thus, a
      service MUST make a policy decision about whether the IDP is
      permitted to assert a particular attribute and about whether the
      asserted value is acceptable.</t>
      <t>In contrast, attributes in an enterprise context are often
      verified by a central authentication infrastructure that is
      trusted to assert most or all attributes. For example, in a Kerberos infrastructure, the KDC typically indicates group membership information for clients to a server using KDC-authenticated authorization data.</t>
<t>The context of an attribute is an important property of that
      attribute; trust context is an important part of the
      context. In order for applications to distinguish the context of
      attributes, attributes with different context need different
      names.  This specification defines attribute names for SAML and AA attributes in the federated context. </t>
      <t>These names MUST not be used for attributes issued by a party other 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 can consult whatever sources of attributes it chooses, but acceptors can assume attributes in the federated context are from the source of credentials.</t>
    </section>
    <section title="Name Attributes for GSS-EAP">
      <t>This section describes how RADIUS attributes received with the GSS-EAP mechanism are named.</t>
      <t>The first portion of the name is TBD1 (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 2.6 of <xref target="I-D.ietf-radext-radius-extensions"/>. For example the name of the User-Name attribute is "TBD 1". The name of extended type 1 within type 241 would be "TBD 241.1".</t>
      <t>The value of RADIUS attributes is the raw octets of the packet. Integers are in network byte order. The display value SHOULD be a human readable string; an implementation can only produce this string if it knows the type of a given RADIUS attribute.</t>
    </section>
    <section title="Names of SAML Attributes in the Federated Context">
      <section title="Assertions">
	<t>An assertion generated by the credential source is named by "urn:ietf:params:gss-eap:saml-aaa-assertion". The
	value of this attribute is the assertion carried in the AAA
	protocol or used for authentication in a SAML mechanism. This attribute is absent from a given acceptor name
	if no such assertion is present or if the assertion fails
	local policy checks. This attribute is always
	authentic when present: authentication only succeeds if the
	AAA exchange is successfully authenticated. However, users of
	the GSS-API MUST confirm that the attribute is authenticated
	because some mechanisms MAY permit an initiator to assert an
	unauthenticated version of this attribute.</t> 
      </section>
      <section title="SAML Attributes">
	<t>Each attribute carried in the assertion SHOULD also be a
	GSS name attribute. The name of this attribute has three
	parts, all separated by an ASCII space character. The first
	part is urn:ietf:params:gss-eap:saml-attr. The second part is
	the URI for the SAML attribute name format. The final part is
	the name of the SAML attribute. </t>
	<t>These attributes SHOULD be marked authenticated if they are
	contained in SAML assertions that have been successfully
	validated back to the trusted source of the peer
	credential. In the GSS-EAP mechanism, a SAML assertion carried
	in an integrity-protected and authenticated AAA protocol SHALL
	be sufficiently validated. An implementation MAY apply local
	policy checks to this assertion and discard it if it is
	unacceptable according to these checks.</t>
      </section>
    </section>
        <section title="Security Considerations">
      <t>This document describes how to access RADIUS attributes, SAML attributes and SAML assertions from some GSS-API mechanisms. These attributes are typically used for one of two purposes. The least sensitive is personalization: a central service MAY provide information about an authenticated user so they need not enter it with each acceptor they access. A more sensitive use is authorization.</t>
      <t>The mechanism is responsible for authentication and integrity protection of the attributes. However, the acceptor application is responsible for making a decision about whether the credential source is trusted to assert the attribute and validating the asserted value. </t>
        </section>
    <section title="IANA Considerations">
      <t>This section needs to include URN registrations within the
      IETF namespace for URNs that are used.</t>
    </section>
    </middle>

    <back>
        <references title='Normative References'>&rfc2119;
    &gss-eap;
&gss-naming;
      &rfc2743;
      <?rfc include='http://xml.resource.org/public/rfc/bibxml3/reference.I-D.ietf-radext-radius-extensions'?>

</references>
    <references title="Informative References">
      <?rfc include='http://xml.resource.org/public/rfc/bibxml3/reference.I-D.ietf-kitten-sasl-saml-ec'?>

    </references>
    </back>

</rfc>