OAuth Token Introspection
draft-richer-oauth-introspection-00

Abstract

This specification defines a method for a client or protected resource to query an OAuth authorization server to determine meta-information about an OAuth token.

Requirements Language

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].

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http:/⁠/⁠datatracker.ietf.org/⁠drafts/⁠current/⁠.

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."

This Internet-Draft will expire on May 31, 2013.

Copyright Notice

Copyright (c) 2012 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 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. Introspection Endpoint
• 2.1. Introspection Request
• 2.2. Introspection Response
• 2.3. Non-normative Example
• 3. IANA Considerations
• 4. Security Considerations
• 5. Acknowledgements
• 6. Normative References
• Author's Address

1. Introduction

In OAuth, the contents of tokens are opaque to clients. This means that the client does not need to know anything about the content or structure of the token itself, if there is any. However, there is still a large amount of metadata that may be attached to a token, such as its current validity, approved scopes, and extra information about the authentication context in which the token was issued.

This specification defines an Introspection Endpoint that allows the holder of a token to query the Authorization Server to discover the set of meta-information for a token.

2. Introspection Endpoint

The Introspection Endpoint is an OAuth 2 Endpoint that responds to HTTP GET and HTTP POST requests from token holders. The endpoint takes a single parameter representing the token (and optionally further authentication) and returns a JSON document representing the meta information surrounding the token.

2.1. Introspection Request

OAuth 2 Core Specification [RFC6749] or a separate OAuth2 Access Token. The methods of managing and validating these authentication credentials are out of scope of this specification.

token

the string value of the token.

The endpoint SHOULD also require some form of authentication to access this endpoint, such as the Client Authentication as described in

2.2. Introspection Response

The server responds with a JSON object in application/json format with the following top-level members. Specific implementations MAY extend this structure with their own service-specific pieces of information.

valid

REQUIRED. Boolean indicator of whether or not the presented token is valid.

expires_at

OPTIONAL. Integer timestamp, measured in the number of seconds since January 1 1970 UTC, indicating when this token will expire.

issued_at

OPTIONAL. Integer timestamp, measured in the number of seconds since January 1 1970 UTC, indicating when this token was originally issued.

scope

OPTIONAL. Array of strings representing the scopes associated with this token.

user_id

OPTIONAL. Local identifier of the Resource Owner who authorized this token.

client_id

OPTIONAL. Client Identifier for the Client that requested this token.

audience

OPTIONAL. Service-specific string identifier of the intended audience for this token.

2.3. Non-normative Example

For example, a Protected Resource accepts a request from a Client carrying an OAuth2 Bearer Token. In order to know how and whether to serve the request, the Protected Resource then makes the following request to the Introspection Endpoint of the Authorization Server.

Following is a non-normative example request (with line wraps for display purposes only):

POST /register HTTP/1.1
Accept: application/x-www-form-urlencoded
Host: server.example.com
Authorization: Basic czZCaGRSa3F0Mzo3RmpmcDBaQnIxS3REUmJuZlZkbUl3

token=X3241Affw.4233-99JXJ

The Authorization Server validates the client credentials and looks up the information in the token. If the token is valid, it returns the following JSON document.

Following is a non-normative example request (with line wraps for display purposes only):

HTTP/1.1 200 OK
Content-Type: application/json
Cache-Control: no-store

{
 "valid": true,
 "client_id":"s6BhdRkqt3",
 "scope": ["read", "write", "dolphin"],
 "user_id": "2309fj32kl",
 "audience": "http://example.org/protected-resource/*"
}

If the token presented is not valid (but the authentication presented is valid), it returns the following JSON document.

Following is a non-normative example request (with line wraps for display purposes only):

HTTP/1.1 200 OK
Content-Type: application/json
Cache-Control: no-store

{
 "valid": false
}

If the credentials are invalid, the Authorization Server responds with the appropriate error response from the OAuth2 Core.

3. IANA Considerations

This document makes no request of IANA.

4. Security Considerations

If left unprotected and un-throttled, the Introspection Endpoint could present a means for an attacker to poll a series of possible token values, fishing for a valid token. Therefore, the Authorization Server SHOULD issue special client credentials to any protected resources or clients that need to access the introspection endpoint. These credentials may be used directly at the endpoint, or they may be exchanged for an OAuth2 Access token scoped specifically for the Introspection Endpoint.

5. Acknowledgements

Thanks to the OAuth Working Group for feedback.

6. Normative References

Author's Address