Network Working Group G. Zorn Internet-Draft Network Zen Intended status: Informational June 24, 2009 Expires: December 26, 2009 RADIUS Attributes for IEEE 802.16 Privacy Key Management Version 1 (PKMv1) Protocol Support draft-zorn-radius-pkmv1-04.txt Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on December 26, 2009. Copyright Notice Copyright (c) 2009 IETF Trust and the persons identified as the document authors. All rights reserved. Zorn Expires December 26, 2009 [Page 1]
Internet-Draft RADIUS Attributes for PKMv1 June 2009 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. Abstract This document defines a set of RADIUS Attributes which are designed to provide RADIUS support for IEEE 802.16 Privacy Key Management Version 1. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1. Specification of Requirements . . . . . . . . . . . . . . 3 2.2. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Attributes . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.1. PKM-SS-Cert . . . . . . . . . . . . . . . . . . . . . . . 4 3.2. PKM-CA-Cert . . . . . . . . . . . . . . . . . . . . . . . 5 3.3. PKM-Config-Settings . . . . . . . . . . . . . . . . . . . 6 3.4. PKM-Cryptosuite-List . . . . . . . . . . . . . . . . . . . 8 3.5. PKM-SAID . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.6. PKM-SA-Descriptor . . . . . . . . . . . . . . . . . . . . 9 3.7. PKM-AUTH-Key . . . . . . . . . . . . . . . . . . . . . . . 10 4. Table of Attributes . . . . . . . . . . . . . . . . . . . . . 11 5. Diameter Considerations . . . . . . . . . . . . . . . . . . . 12 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 6.1. Attributes . . . . . . . . . . . . . . . . . . . . . . . . 12 7. Security Considerations . . . . . . . . . . . . . . . . . . . 12 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 9.1. Normative References . . . . . . . . . . . . . . . . . . . 13 9.2. Informative References . . . . . . . . . . . . . . . . . . 13 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 14 Zorn Expires December 26, 2009 [Page 2]
Internet-Draft RADIUS Attributes for PKMv1 June 2009 1. Introduction Privacy Key Management Version 1 (PKMv1) [IEEE.802.16-2004] is a public-key based authentication and key establishment protocol typically used in fixed wireless broadband network deployments. The protocol utilizes X.509 v3 certificates [RFC2459], RSA encryption [PKCS.1.1998] and a variety of secret key cryptographic methods to allow an 802.16 Base Station (BS) to authenticate a Subscriber Station (SS) and perform key establishment and maintenance between a SS and BS. This document defines a set of RADIUS Attributes which are designed to provide support for PKMv1. The target audience for this document consists of those developers implementing RADIUS support for PKMv1; therefore, familiarity with (or at least access to) the IEEE 802.16- 2004 standard is assumed. Discussion of this draft may be directed to the author. 2. Terminology 2.1. Specification of Requirements The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 2.2. Acronyms CA Certificate Authority; trusted party issuing and signing X.509 certificates For further information on the following terms, please see [IEEE.802.16-2004]. SA Security Association SAID Security Association Identifier TEK Traffic Encryption Key Zorn Expires December 26, 2009 [Page 3]
Internet-Draft RADIUS Attributes for PKMv1 June 2009 3. Attributes The following subsections describe the Attributes defined by this document. This specification concerns the following values: <TBD1> PKM-SS-Cert <TBD2> PKM-CA-Cert <TBD3> PKM-Config-Settings <TBD4> PKM-Cryptosuite-List <TBD5> PKM-SAID <TBD6> PKM-SA-Descriptor <TBD7> PKM-Auth-Key 3.1. PKM-SS-Cert Description The PKM-SS-Cert Attribute is variable length and MAY be transmitted in the Access-Request message. The Value field is of type String and contains the X.509 certificate [RFC2459] binding a public key to the identifier of the Subscriber Station. It is possible that the size of the SS certificate may exceed the maximum size of a RADIUS attribute; in this case, the client MUST encapsulate the certificate in the Value fields of two or more instances of the PKM-SS-Cert Attributes, each (except possibly the last) having a length of 255 octets. If multiple PKM-SS-Cert Attributes are contained within an Access-Request packet, they MUST be in order and MUST be consecutive attributes in the packet. Upon receipt, the RADIUS server MUST recover the original certificate by concatenating the Value fields of the received PKM- SS-Cert Attributes in order. A summary of the PKM-SS-Cert Attribute format is shown below. The fields are transmitted from left to right. 1 2 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Len | Value... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Zorn Expires December 26, 2009 [Page 4]
Internet-Draft RADIUS Attributes for PKMv1 June 2009 Type <TBD1> for PKM-SS-Cert Len > 2 Value The Value field is variable length and contains a (possibly complete) portion of an X.509 certificate. 3.2. PKM-CA-Cert Description The PKM-CA-Cert Attribute is variable length and MAY be transmitted in the Access-Request message. The Value field is of type String and contains the X.509 certificate [RFC2459] used by the CA to sign the SS certificate carried in the PKM-SS-Cert attribute (Section 3.1) in the same message. It is possible that the size of the CA certificate may exceed the maximum size of a RADIUS attribute; in this case, the client MUST encapsulate the certificate in the Value fields of two or more instances of the PKM-CA-Cert Attributes, each (except possibly the last) having a length of 255 octets. If multiple PKM-CA-Cert Attributes are contained within an Access-Request packet, they MUST be in order and MUST be consecutive attributes in the packet. Upon receipt, the RADIUS server MUST recover the original certificate by concatenating the Value fields of the received PKM- CA-Cert Attributes in order. A summary of the PKM-CA-Cert Attribute format is shown below. The fields are transmitted from left to right. 1 2 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Len | Value... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type <TBD2> for PKM-CA-Cert Zorn Expires December 26, 2009 [Page 5]
Internet-Draft RADIUS Attributes for PKMv1 June 2009 Len > 2 Value The Value field is variable length and contains a (possibly complete) portion of an X.509 certificate. 3.3. PKM-Config-Settings Description The PKM-Config-Settings Attribute is 30 octets in length and consists of seven independent fields, each of type integer [RFC2865]. Each of the fields contains a timeout value and corresponds to a Type-Length-Value (TLV) tuple encapsulated in the IEEE 802.16 "PKM configuration settings" attribute; for details on the contents of each field, see [IEEE.802.16-2004]. One instance of the PKM-Config-Settings Attribute MAY be included in the Access-Accept message. A summary of the PKM-Config-Settings Attribute format is shown below. The fields are transmitted from left to right. 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Len | Auth Wait Timeout +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Auth Wait Timeout (cont.) | Reauth Wait Timeout +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Reauth Wait Timeout (cont.) | Auth Grace Time +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Auth Grace Time (cont.) | Op Wait Timeout +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Op Wait Timeout (cont.) | Rekey Wait Timeout +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Rekey Wait Timeout (cont.) | TEK Grace Time +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ TEK Grace Time (cont.) | Auth Rej Wait Timeout +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Auth Rej Wait Timeout (cont.) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Zorn Expires December 26, 2009 [Page 6]
Internet-Draft RADIUS Attributes for PKMv1 June 2009 Type <TBD3> for PKM-Config-Settings Len 30 Auth Wait Timeout The Auth Wait Timeout field is 4 octets in length and corresponds to the "Authorize wait timeout" field of the 802.16 "PKM configuration settings" attribute [IEEE.802.16-2004]. Reauth Wait Timeout The Reauth Wait Timeout field is 4 octets in length and corresponds to the "Reauthorize wait timeout" field of the 802.16 "PKM configuration settings" attribute [IEEE.802.16-2004]. Auth Grace Time The Auth Grace Time field is 4 octets in length and corresponds to the "Authorize grace time" field of the 802.16 "PKM configuration settings" attribute [IEEE.802.16-2004]. Op Wait Timeout The Op Wait Timeout field is 4 octets in length and corresponds to the "Operational wait timeout" field of the 802.16 "PKM configuration settings" attribute [IEEE.802.16-2004]. Rekey Wait Timeout The Rekey Wait Timeout field is 4 octets in length and corresponds to the "Rekey wait timeout" field of the 802.16 "PKM configuration settings" attribute [IEEE.802.16-2004]. TEK Grace Time The TEK Grace Time field is 4 octets in length and corresponds to the "TEK grace time" field of the 802.16 "PKM configuration settings" attribute [IEEE.802.16-2004]. Auth Rej Wait Timeout The Auth Rej Wait Timeout field is 4 octets in length and corresponds to the "Authorize reject wait timeout" field of the Zorn Expires December 26, 2009 [Page 7]
Internet-Draft RADIUS Attributes for PKMv1 June 2009 802.16 "PKM configuration settings" attribute [IEEE.802.16-2004]. 3.4. PKM-Cryptosuite-List Description The PKM-Cryptosuite-List Attribute is variable length and corresponds roughly to the "Cryptographic-Suite-List" 802.16 attribute [IEEE.802.16-2004], the difference being that the RADIUS Attribute contains only the 3 octet cryptographic suite identifiers, omitting the IEEE Type and Length fields. The PKM-Cryptosuite-List Attribute MAY be present in an Access- Request message. Implementation Note The PKM-Cryptosuite-List Attribute is used as a building block to create the 802.16 "Security-Capabilities" attribute; since this document only pertains to PKM version 1, the "Version" sub-attribute in that structure MUST be set to 0x01 when the RADIUS client constructs it. A summary of the PKM-Cryptosuite-List Attribute format is shown below. The fields are transmitted from left to right. 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Len | Value... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type <TBD4> for PKM-Cryptosuite-List Len 2 + 3n, where 'n' is the number of cryptosuite identifiers in the list Value The Value field is variable length and contains a sequence of one or more cryptosuite identifiers, each of which is 3 octets in length and corresponds to the Value field of an IEEE 802.16 Zorn Expires December 26, 2009 [Page 8]
Internet-Draft RADIUS Attributes for PKMv1 June 2009 Cryptographic-Suite attribute. 3.5. PKM-SAID Description The PKM-SAID Attribute is 4 octets in length and contains a PKM Security Association Identifier [IEEE.802.16-2004]. It MAY be included in an Access-Request message. A summary of the PKM-SAID Attribute format is shown below. The fields are transmitted from left to right. 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Len | SAID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type <TBD5> for PKM-SAID Len 4 SAID The SAID field is two octets in length and corresponds to the Value field of the 802.16 PKM SAID attribute. 3.6. PKM-SA-Descriptor Description The PKM-SA-Descriptor Attribute is 8 octets in length. It contains three fields, described below, which together specify the characteristics of a PKM security association. One or more instances of the PKM-SA-Descriptor Attribute MAY occur in an Access-Accept message. A summary of the PKM-SA-Descriptor Attribute format is shown below. The fields are transmitted from left to right. Zorn Expires December 26, 2009 [Page 9]
Internet-Draft RADIUS Attributes for PKMv1 June 2009 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Len | SAID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SA Type | Cryptosuite | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type <TBD6> for PKM-SA-Descriptor Len 8 SAID The SAID field is two octets in length and contains a PKM SAID (Section 3.5). SA Type The SA Type field is one octet in length. The contents correspond to those of the Value field of an IEEE 802.16 SA-Type attribute. Cryptosuite The Cryptosuite field is 3 octets in length. The contents correspond to those of the Value field of an IEEE 802.16 Cryptographic-Suite attribute. 3.7. PKM-AUTH-Key Description The PKM-AUTH-Key Attribute is 135 octets in length. It consists of 3 fields, described below, which together specify the characteristics of a PKM authorization key. The PKM-AUTH-Key Attribute MAY occur in an Access-Accept message. Any packet that contains an instance of the PKM-AUTH-Key Attribute MUST also contain an instance of the Message-Authenticator Attribute [RFC3579]. A summary of the PKM-AUTH-Key Attribute format is shown below. The fields are transmitted from left to right. Zorn Expires December 26, 2009 [Page 10]
Internet-Draft RADIUS Attributes for PKMv1 June 2009 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Len | Lifetime +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Lifetime (cont.) | Sequence | Key... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type <TBD7> for PKM-AUTH-Key Len 135 Lifetime The Lifetime field is 4 octets in length and represents the lifetime of the authorization key. Sequence The Sequence field is one octet in length. The contents correspond to those of the Value field of an IEEE 802.16 Key- Sequence attribute. Key The Key field is 128 octets in length. The contents correspond to those of the Value field of an IEEE 802.16 AUTH-Key attribute. The Key field MUST be encrypted under the public key from the Subscriber Station certificate (Section 3.1) using RSA encryption [PKCS.1.1998]; see [IEEE.802.16-2004] for further details. 4. Table of Attributes The following table provides a guide to which attributes may be found in which kinds of packets, and in what quantity. Request Accept Reject Challenge Acct-Req # Attribute 0-1 0 0 0 0 TBD1 PKM-SS-Cert 0-1 0 0 0 0 TBD2 PKM-CA-Cert 0 0-1 0 0 0 TBD3 PKM-Config-Settings 0-1 0 0 0 0 TBD4 PKM-Cryptosuite-List 0-1 0 0 0 0 TBD5 PKM-SAID 0 0+ 0 0 0 TBD6 PKM-SA-Descriptor Zorn Expires December 26, 2009 [Page 11]
Internet-Draft RADIUS Attributes for PKMv1 June 2009 0 0-1 0 0 0 TBD7 PKM-Auth-Key 5. Diameter Considerations Since the Attributes defined in this document are allocated from the standard RADIUS type space (see Section 6), no special handling is required by Diameter entities. 6. IANA Considerations This section explains the criteria to be used by the IANA for assignment of numbers within namespaces used within this document. 6.1. Attributes Upon publication of this document as an RFC, IANA must assign numbers for the following Attributes: <TBD1> PKM-SS-Cert <TBD2> PKM-CA-Cert <TBD3> PKM-Config-Settings <TBD4> PKM-Cryptosuite-List <TBD5> PKM-SAID <TBD6> PKM-SA-Descriptor <TBD7> PKM-Auth-Key The Attribute numbers are to be allocated from the standard RADIUS Attribute type space according to the "IETF Review" policy [RFC5226]. 7. Security Considerations If the Access-Accept message is not subject to strong integrity protection, an attacker may be able to modify the contents of the PKM-Auth-Key Attribute. For example, the Key field could be replaced with a key known to the attacker. Although it is necessary for a plaintext copy of the Key field in the PKM-AUTH-Key Attribute to be transmitted in the Access-Accept message, this document does not define a method for doing so Zorn Expires December 26, 2009 [Page 12]
Internet-Draft RADIUS Attributes for PKMv1 June 2009 securely. In order to transfer the key securely, it is RECOMMENDED that it be encapsulated in an instance of the MS-MPPE-Send-Key Attribute [RFC2548]. 8. Acknowledgements Thanks to Alfred Hoenes for review and useful feedback. 9. References 9.1. Normative References [IEEE.802.16-2004] "Information technology - Telecommunications and information exchange between systems - Local and metropolitan area networks - Specific requirements - Part 16: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications", IEEE Standard 802.16, 2004, <http://standards.ieee.org/getieee802/ download/802.16-2004.pdf>. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson, "Remote Authentication Dial In User Service (RADIUS)", RFC 2865, June 2000. [RFC3579] Aboba, B. and P. Calhoun, "RADIUS (Remote Authentication Dial In User Service) Support For Extensible Authentication Protocol (EAP)", RFC 3579, September 2003. [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. 9.2. Informative References [PKCS.1.1998] Kaliski, BK. and JS. Staddon, "RSA Encryption Standard, Version 2.0", PKCS 1, October 1998, <ftp://ftp.rsasecurity.com/pub/pkcs/ascii/pkcs-1v2.asc>. [RFC2459] Housley, R., Ford, W., Polk, T., and D. Solo, "Internet X.509 Public Key Infrastructure Certificate and CRL Profile", RFC 2459, January 1999. Zorn Expires December 26, 2009 [Page 13]
Internet-Draft RADIUS Attributes for PKMv1 June 2009 [RFC2548] Zorn, G., "Microsoft Vendor-specific RADIUS Attributes", RFC 2548, March 1999. Author's Address Glen Zorn Network Zen 1310 East Thomas Street #306 Seattle, Washington 98102 USA Phone: +1 (206) 377-9035 Email: gwz@net-zen.net Zorn Expires December 26, 2009 [Page 14]
