Metadata discovery for third party authorized TURN session
draft-reddy-tram-token-metadata-00
The information below is for an old version of the document.
| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Tirumaleswar Reddy.K , Suhas Nandakumar , Dan Wing , Brandon Williams | ||
| Last updated | 2015-08-28 | ||
| Stream | (None) | ||
| Formats | plain text xml htmlized pdfized bibtex | ||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | I-D Exists | |
| Telechat date | (None) | ||
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| Send notices to | (None) |
draft-reddy-tram-token-metadata-00
TRAM T. Reddy
Internet-Draft S. Nandakumar
Intended status: Standards Track D. Wing
Expires: February 29, 2016 Cisco
B. Williams
Akamai, Inc.
August 28, 2015
Metadata discovery for third party authorized TURN session
draft-reddy-tram-token-metadata-00
Abstract
The operator of the TURN server might want to have fine grained
control on the clients usage of the server resources for providing
features such as limiting the bandwith usage, number of allocations
and so on. This document proposes a generic mechanism for the
operator to introspect the access token to retrieve any policy
restrictions imposed by the authorization server on the TURN server
resources assigned to the client.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on February 29, 2016.
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
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carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Introspection Request . . . . . . . . . . . . . . . . . . . . 3
4. Introspection Response . . . . . . . . . . . . . . . . . . . 4
5. INTROSPECTION_ENDPOINT Attribute . . . . . . . . . . . . . . 5
6. Notifications from Introspection Endpoint . . . . . . . . . . 5
7. Alternate approach . . . . . . . . . . . . . . . . . . . . . 6
8. Security Considerations . . . . . . . . . . . . . . . . . . . 6
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
9.1. JSON Web Token Claims . . . . . . . . . . . . . . . . . . 6
9.2. Well-Known 'introspection' URI . . . . . . . . . . . . . 7
9.3. STUN attribute . . . . . . . . . . . . . . . . . . . . . 7
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
11.1. Normative References . . . . . . . . . . . . . . . . . . 7
11.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8
1. Introduction
The TURN protocol [RFC5766] is used to setup a relay service (via a
TURN Server) to exchange traffic (real time media, data) between
peers when direct peer-to-peer connection is not otherwise possible.
Due to the costs associated with operating a relay service, it is
important to constrain resource usage. For example, the operator
might want to limit the number of allocations or bandwidth.
[I-D.ietf-tram-turn-third-party-authz] allows clients to obtain
OAuth2.0 access token (of type 'Assertion') authorized by a
Authorization Server to access a given TURN server. On receiving
such a token, the TURN server validates the token to grant or reject
access to the session resources. However, having a token doesn't
provide any control for the operator of the TURN server restrict the
server's resources. This specification proposes using the mechanism
defined in [I-D.ietf-oauth-introspection] to query OAuth2.0
authorization server to determine resource restrictions for this
token.
The rest of the document is organized as follows. Section 3 provides
procedure for querying the OAuth2.0 introspection endpoint and
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Section 4 shows the introspection response with the parameters
identifying the policy controls associated with the access token.
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 [RFC2119].
This document defines the following terms:
Access Token: OAuth 2.0 access token.
Token Introspection: The act of inquiring about the current state of
an OAuth 2.0 token through use of the network protocol defined in
this document.
Introspection Endpoint: The OAuth 2.0 endpoint through which the
token introspection operation is accomplished. The Introspection
Endpoint could be a WebRTC server.
3. Introspection Request
For introspecting the meta-information associated with the access
token, the TURN server shall execute the procedures defined in
Section 2.1 of [I-D.ietf-oauth-introspection].
POST {scheme}://{host}:{port}/.well-known/introspection
Accept: application/json
Content-Type: application/x-www-form-urlencoded
{
"token" : "string"
"token_type_hint" : "string"
}
token REQUIRED. This parameter is defined in
[I-D.ietf-oauth-introspection]. The access token is conveyed by
the TURN client to the TURN server as discussed in Section 3.1
of [I-D.ietf-tram-turn-third-party-authz].
token_type_hint OPTIONAL. This parameter is defined in
[I-D.ietf-oauth-introspection]. The token type MUST be set to
'access_token' defined in [RFC7009]. If the token type is not
'access_token', the server rejects the request with a 400 (Bad
Request) error.
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Following is a non-normative example request showcasing the
introspection request for a given access token.
POST /introspect HTTP/1.1
Host: server.example.com
Accept: application/json
Content-Type: application/x-www-form-urlencoded
{
"token" : "2YotnFZFEjr1zCsicMWpAA"
"token_type_hint" : "access_token"
}
4. Introspection Response
The OAuth2.0 Introspection Endpoint on recognizing the token,
responds with a JSON object [RFC7159] in "application/json" format
with the following members.
HTTP/1.1 200 OK
Content-Type: application/json
{
"active" : "boolean",
"scope" : "string",
"max_upstream_bandwidth" : "unsigned integer",
"max_downstream_bandwidth" : "unsigned integer",
"max_allocations" : "unsigned integer",
"lifetime" : "unsigned integer",
}
active REQUIRED. This parameter is defined in
[I-D.ietf-oauth-introspection].
scope OPTIONAL. This parameter is defined in
[I-D.ietf-oauth-introspection]. For this specification, the
scope MUST be 'stun'.
max_upstream_bandwidth REQUIRED. The value of this parameter is
an 64 bit unsigned integer that represents the maximum upstream
bandwidth permitted for the token in kilobits per second (1
kilobit = 1024 bits).
max_downstream bandwidth REQUIRED. The value of this parameter
is an 64 bit unsigned integer that represents the maximum
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downstream bandwidth permitted for the token in kilobits per
second (1 kilobit = 1024 bits).
max_allocations: REQUIRED. 16 bit unsigned integer defining
maximum number of allocations that is allowable for the given
access token.
lifetime: REQUIRED: The lifetime of the access token, in
seconds.
NOTE: Future specifications are allowed to define further top-level
members as mandated by the use-cases.
Following is a non-normative example response:
HTTP/1.1 200 OK
Content-Type: application/json
{
"active" : true,
"scope" : "stun",
"upstream-bandwidth" : 4096,
"downstream-bandwidth" : 4096,
"max-allocations" : 1,
}
5. INTROSPECTION_ENDPOINT Attribute
This attribute is used by the TURN client to inform the TURN server
the FQDN of Introspection Endpoint.
The TURN server establishes an HTTPS connection with the indicated
server and sends the above-described communications to that server.
The INTROSPECTION_ENDPOINT attribute is a comprehension-optional
attribute (see Section 15 from [RFC5389]).
TBD: An alternate approach is to convey the FQDN in the token itself.
6. Notifications from Introspection Endpoint
Introspection Endpoint can send unsolicited responses to notify
updates to the metadata associated with the token to the TURN server
using HTTP/2 server push mechanism. Examples where such
notifications are desired are:
o The Introspection Endpoint can signal the TURN server to revoke
the access token after the call is terminated by setting lifetime
to zero.
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o When the call switches from audio to video, the Introspection
Endpoint notifies the increased bandwidth to the TURN server.
7. Alternate approach
TBD:
Another approach, not discussed in this document, is a self-
contained token where the metadata is contained within the token
itself. This approach has the benefit of avoiding a protocol between
the TURN server and the Introspection Endpoint. However, this
approach has the following drawbacks:
o Needs a large TURN packet to accommodate the token.
o Token needs versioning for future enhancements, and the
Introspection Endpoint needs a mechanism to learn the token
version supported by the TURN server.
o Introspection Endpoint cannot notify changes to the metadata
associated with the token to the TURN server.
8. Security Considerations
The Security Considerations and Privacy Considerations of
[I-D.ietf-oauth-introspection] apply to this document.
9. IANA Considerations
9.1. JSON Web Token Claims
This specification requests IANA to register the following values
into the IANA JSON Web Token Claims registry for JWT Claim Names.
o Claim Name: "max_upstream_bandwidth"
o Claim Description: Maximum limit of upstream bandwidth
o Change Controller: IESG
o Specification Document(s): Section 4 of [[ this document ]].
o Claim Name: "max_downstream_bandwidth"
o Claim Description: Maximum limit of downstream bandwidth
o Change Controller: IESG
o Specification Document(s): Section 4 of [[ this document ]].
o Claim Name: "max_allocations"
o Claim Description: Maximum number of allocations
o Change Controller: IESG
o Specification Document(s): Section 4 of [[ this document ]].
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9.2. Well-Known 'introspection' URI
This memo registers the 'introspection' well-known URI in the Well-
Known URIs registry as defined by [RFC5785].
URI suffix: introspection
Change controller: IETF
Specification document(s): This document
Related information: None
9.3. STUN attribute
[Paragraphs below in braces should be removed by the RFC Editor upon
publication]
[IANA is requested to add the following attributes to the STUN
attribute registry [iana-stun], the INTROSPECTION_ENDPOINT attribute
requires that IANA allocate a value in the "STUN attributes Registry"
from the comprehension-optional range (0x8000-0xBFFF)].
This document defines the INTROSPECTION_ENDPOINT attribute, described
in Section 5. IANA has allocated the comprehension-optional
codepoint TBD for this attribute.
10. Acknowledgements
TODO
11. References
11.1. Normative References
[I-D.ietf-oauth-introspection]
Richer, J., "OAuth 2.0 Token Introspection", draft-ietf-
oauth-introspection-11 (work in progress), July 2015.
[I-D.ietf-tram-turn-third-party-authz]
Reddy, T., Patil, P., R, R., and J. Uberti, "Session
Traversal Utilities for NAT (STUN) Extension for Third
Party Authorization", draft-ietf-tram-turn-third-party-
authz-16 (work in progress), May 2015.
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[iana-stun]
IANA, , "IANA: STUN Attributes", April 2011,
<http://www.iana.org/assignments/stun-parameters/stun-pa
rameters.xml>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC5389] Rosenberg, J., Mahy, R., Matthews, P., and D. Wing,
"Session Traversal Utilities for NAT (STUN)", RFC 5389,
DOI 10.17487/RFC5389, October 2008,
<http://www.rfc-editor.org/info/rfc5389>.
[RFC5766] Mahy, R., Matthews, P., and J. Rosenberg, "Traversal Using
Relays around NAT (TURN): Relay Extensions to Session
Traversal Utilities for NAT (STUN)", RFC 5766,
DOI 10.17487/RFC5766, April 2010,
<http://www.rfc-editor.org/info/rfc5766>.
11.2. Informative References
[RFC5785] Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known
Uniform Resource Identifiers (URIs)", RFC 5785,
DOI 10.17487/RFC5785, April 2010,
<http://www.rfc-editor.org/info/rfc5785>.
[RFC7009] Lodderstedt, T., Ed., Dronia, S., and M. Scurtescu, "OAuth
2.0 Token Revocation", RFC 7009, DOI 10.17487/RFC7009,
August 2013, <http://www.rfc-editor.org/info/rfc7009>.
[RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
2014, <http://www.rfc-editor.org/info/rfc7159>.
Authors' Addresses
Tirumaleswar Reddy
Cisco Systems, Inc.
Email: tireddy@cisco.com
Suhas Nandakumar
Cisco Systems, Inc.
Email: snandaku@cisco.com
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Dan Wing
Cisco Systems, Inc.
170 West Tasman Drive
San Jose, California 95134
USA
Email: dwing@cisco.com
Brandon Williams
Akamai, Inc.
8 Cambridge Center
Cambridge, MA 02142
USA
Email: brandon.williams@akamai.com
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