Internet DRAFT - draft-atwood-mcast-user-auth
draft-atwood-mcast-user-auth
MBONED Working Group W. Atwood
Internet-Draft Concordia University/CSE
Intended status: Standards Track S. Islam
Expires: September 9, 2010 INRS-EMT
March 08, 2010
Multicast User Authentication
draft-atwood-mcast-user-auth-01
Abstract
RFC 1112 offers no facilities for participant control or accounting.
This document explores the requirements for such facilities, and
offers a potential solution, based on extending the IGMP and MLD
"join" operations to carry EAP and/or ERP packets.
Status of this Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Problem Statement . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Authenticating and Authorizing Multicast Users . . . . . . 4
3.2. Re-authentication and Re-authorization . . . . . . . . . . 4
3.3. Accounting . . . . . . . . . . . . . . . . . . . . . . . . 5
3.4. Independence of Authentication and Authorization
Procedures . . . . . . . . . . . . . . . . . . . . . . . . 5
3.5. Coupling of Network and Application Level Controls . . . . 5
3.6. Separation of Network Access Controls from Group
Access Controls . . . . . . . . . . . . . . . . . . . . . . 5
4. Proposed Solution . . . . . . . . . . . . . . . . . . . . . . . 5
5. Protocol Details . . . . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
9.1. Normative References . . . . . . . . . . . . . . . . . . . 7
9.2. Informative References . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8
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1. Introduction
The procedure for joining a network-level IP multicast group
[RFC1112] an open one---a request is made by the receiving host,
using MLD (IPv6) [RFC3810] or IGMP (IPv4) [RFC3376], and the
multicast routing protocol (typically PIM-SM [RFC4601]) is
responsibile for building a Data Distribution Tree (DDT) to ensure
that the data are delivered to the receiving host(s).
The procedure for joining an application-level group clearly depends
on the application. When IP multicast is used as the data
distribution technology, then it is desirable to be able to limit
delivery of the network-level multicast data packets to those hosts
that have receiving users who are valid members of the application-
level group.
The anyone-can-send, anyone-can-receive nature of IP multicast
[RFC1112] has resulted in restricted deployment of multicast
distribution technology, since it is impossible to generate any
revenue from services based on standard multicast.
However, several pieces of the problem have received significant
attention in recent years. The problem of security and key
management for application-level groups has been explored by the
Multicast Security (MSEC) working group, and a framework devised
[RFC3740].
The use of AAA protocols (RADIUS [RFC2865], Diameter [RFC3588]) to
manage network-level access has been standardized. These protocols
(especially Diameter) can be extended to permit controlling access to
application-level groups.
The requirements for "well-managed" multicast have been stated in
[I-D.ietf-mboned-maccnt-req], and a framework for satisfying these
requirements with the help of AAA functionality has been described in
[I-D.ietf-mboned-multiaaa-framework].
Finally, work is under way on securing the network routing
infrastructure [I-D.ietf-karp-threats-reqs]
[I-D.ietf-karp-design-guide] [I-D.ietf-karp-framework] and the
exchanges between adjacent multicast routers
[I-D.ietf-pim-sm-linklocal].
However, one key piece is missing. To minimize the resource wastage
that would result from delivering multicast traffic to hosts that
have no entitlement to receive them, it is necessary to authenticate
and authorize receiving users and to correlate their right to access
a group with the action of putting the data on that part of the
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network that is directly connected to the receiving host.
2. Terminology
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 RFC 2119 [RFC2119].
They indicate requirement levels for compliant PIM-SM
implementations.
3. Problem Statement
3.1. Authenticating and Authorizing Multicast Users
The design of IP multicast [RFC1112] ensures that there is no
relationship between the receiving hosts and the sending host(s) in a
network-level multicast group. Multicast sending hosts do not even
know whether there are receiving hosts or not, much less who they are
or whether they are entitled to receive the data. The receiving host
issues a network-level "join" on behalf of a receiving user, using
IGMP (IPv4) [RFC3376] or MLD (IPv6) [RFC3810], and a designated
access router is responsible for grafting itself onto the data
distribution tree. The network exercises no control over this
process---it is required to provide the data flow.
Although specifications exist for encrypting the user data, thus
ensuring that only legitimate users can decrypt these data, these
specifications provide no way to ensure that the data distribution
tree is not extended when a non-authorized receiving user makes a
request to join the tree. Thus, key management and receiving user
access control have to be considered as separate problems.
Given the lack of a relationship between the sending user(s) and the
receiving user(s), it is difficult to create and enforce an
appropriate business model.
3.2. Re-authentication and Re-authorization
Several scenarios can cause a need for re-authentication and re-
authorization:
o When a user changes the group that he/she wishes to attach to;
o When a user changes the access router used for connection (e.g.,
wireless roaming);
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o When a user changes the medium used for physical connectivity
(e.g., cellular to wireless, etc.).
3.3. Accounting
The fact of delivery of group data needs to be recorded, to enable
revenue to be earned. This is only one of a range of accounting
issues that may need to be addressed, which points to the need for a
general solution.
3.4. Independence of Authentication and Authorization Procedures
There is a wide range of authentication and authorization procedures
that may be desired by an Internet Service Provider, including some
that may not yet be standardized. This implies the adoption of a
very general framework for such procedures.
3.5. Coupling of Network and Application Level Controls
It is conceivable that a solution could be found for the above issues
that would be based on standard network protocols and separate
(proprietary or standard) group management protocols. For example,
the key management and distribution protocol associated with the
application-level group could have authentication as one of its
features. However, the separation of the network-level controls from
the application-level controls enables a significant class of
security attacks. It is therefore important that control of access
to the network resources and control of access to the application-
level resources be strongly coupled.
3.6. Separation of Network Access Controls from Group Access Controls
Access to the network is different from access to a group. As an
example, the authorization to watch a particular video presentation
may be associated with a specific family member, while the
authorization to use the network connection may be associated with an
entire family (or to anyone present in the house).
While existing AAA procedures are designed to control network level
access, they must be extended (or alternatives found) if group access
must be controlled.
4. Proposed Solution
Two levels of action are apparent: the action of joining the network-
level data distribution tree, and the action of joining the group,
with its accompanying security properties.
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Joining the data distribution tree should not occur unless and until
the receiving user has been authenticated and authorized. One way to
ensure that this relationship is enforced is to carry the receiving
user authentication material in the network-level join packet.
To support multiple types of authentication methods, the Extensible
Authentication Protocol (EAP) [RFC3748] provides a standardized
solution.
To support a method-independent and efficient re-authentication, the
EAP Re-Authentication Protocol (ERP) [RFC5296] provides a possible
solution. ERP is applicable for mobile receivers [MulticastMobile].
To permit correlating the join actions (at the group level and the
network level) with the accounting procedures, the EAP/ERP packets
that are delivered to the access router by the extended network-level
join can be forwarded to the local AAA server for a decision, using
existing AAA protocols, such as RADIUS or Diameter. In keeping with
the statement in [I-D.ietf-mboned-multiaaa-framework] that "A CP may
delegate AAA responsibility to an NSP.", we observe that the NSP can
distribute the responsibility among a collection of local AAA
servers, and that there is sufficient generality in the AAA
architectural model that a wide range of policies could be
implemented, in support of a wide range of business models.
5. Protocol Details
Pending incorporation of the material into this document, readers are
invited to access Islam, et al. [MulticastReceiver].
6. Security Considerations
TBD.
7. IANA Considerations
This document has no actions for IANA.
8. Acknowledgements
9. References
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9.1. Normative References
[RFC1112] Deering, S., "Host extensions for IP multicasting", STD 5,
RFC 1112, August 1989.
[RFC3810] Vida, R. and L. Costa, "Multicast Listener Discovery
Version 2 (MLDv2) for IPv6", RFC 3810, June 2004.
[RFC3376] Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A.
Thyagarajan, "Internet Group Management Protocol, Version
3", RFC 3376, October 2002.
[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.
[RFC3588] Calhoun, P., Loughney, J., Guttman, E., Zorn, G., and J.
Arkko, "Diameter Base Protocol", RFC 3588, September 2003.
[RFC3748] Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H.
Levkowetz, "Extensible Authentication Protocol (EAP)",
RFC 3748, June 2004.
9.2. Informative References
[RFC4601] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas,
"Protocol Independent Multicast - Sparse Mode (PIM-SM):
Protocol Specification (Revised)", RFC 4601, August 2006.
[RFC3740] Hardjono, T. and B. Weis, "The Multicast Group Security
Architecture", RFC 3740, March 2004.
[RFC5296] Narayanan, V. and L. Dondeti, "EAP Extensions for EAP Re-
authentication Protocol (ERP)", RFC 5296, August 2008.
[I-D.ietf-mboned-maccnt-req]
Hayashi, T., Satou, H., Ohta, H., He, H., and S. Vaidya,
"Requirements for Multicast AAA coordinated between
Content Provider(s) and Network Service Provider(s)",
draft-ietf-mboned-maccnt-req-09 (work in progress),
March 2010.
[I-D.ietf-mboned-multiaaa-framework]
Satou, H., Ohta, H., Hayashi, T., Jacquenet, C., and H.
He, "AAA and Admission Control Framework for
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Multicasting", draft-ietf-mboned-multiaaa-framework-11
(work in progress), March 2010.
[I-D.ietf-karp-threats-reqs]
Lebovitz, G., "The Threat Analysis and Requirements for
Cryptographic Authentication of Routing Protocols'
Transports", draft-ietf-karp-threats-reqs-00 (work in
progress), March 2010.
[I-D.ietf-karp-design-guide]
Lebovitz, G. and M. Bhatia, "Keying and Authentication for
Routing Protocols (KARP) Design Guidelines",
draft-ietf-karp-design-guide-00 (work in progress),
February 2010.
[I-D.ietf-karp-framework]
Atwood, W. and G. Lebovitz, "Framework for Cryptographic
Authentication of Routing Protocol Packets on the Wire",
draft-ietf-karp-framework-00 (work in progress),
February 2010.
[I-D.ietf-pim-sm-linklocal]
Atwood, W., Islam, S., and M. Siami, "Authentication and
Confidentiality in PIM-SM Link-local Messages",
draft-ietf-pim-sm-linklocal-10 (work in progress),
December 2009.
[MulticastReceiver]
Islam, S. and W. Atwood, "Multicast Receiver Access
Control by IGMP-AC, Computer Networks,
doi://10.1016/j.comnet.2008.12.005", January 2009.
[MulticastMobile]
Islam, S. and W. Atwood, "Receiver Access Control and
Secured Handoff in Mobile Multicast using IGMP-AC, LCN
2008, pp. 411--418", November 2008.
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Authors' Addresses
J. William Atwood
Concordia University/CSE
1455 de Maisonneuve Blvd, West
Montreal, QC H3G 1M8
Canada
Phone: +1(514)848-2424 ext3046
Email: bill@cse.concordia.ca
URI: http://users.encs.concordia.ca/~bill
Salekul Islam
INRS-EMT
800 de La Gauchetiere, suite 800
Montreal, QC H5A 1K6
Canada
Email: Salekul.Islam@emt.inrs.ca
URI: http://users.encs.concordia.ca/~salek_is
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