[Docs] [txt|pdf|xml|html] [Tracker] [Email] [Diff1] [Diff2] [Nits]

Versions: 00 01

Open Authentication Protocol                         T. Lodderstedt, Ed.
Internet-Draft                                                YES.com AG
Intended status: Standards Track                            V. Dzhuvinov
Expires: November 29, 2018                               Connect2id Ltd.
                                                            May 28, 2018


               JWT Response for OAuth Token Introspection
         draft-lodderstedt-oauth-jwt-introspection-response-01

Abstract

   This draft proposes an additional JSON Web Token (JWT) based response
   for OAuth 2.0 Token Introspection.

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 https://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 November 29, 2018.

Copyright Notice

   Copyright (c) 2018 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
   (https://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.





Lodderstedt & Dzhuvinov Expires November 29, 2018               [Page 1]


Internet-Draft                JWT Response                      May 2018


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Requesting a JWT Response . . . . . . . . . . . . . . . . . .   2
   3.  JWT Response  . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Client Metadata . . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Authorization Server Metadata . . . . . . . . . . . . . . . .   5
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   5
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
     7.1.  OAuth Dynamic Client Registration Metadata Registration .   5
       7.1.1.  Registry Contents . . . . . . . . . . . . . . . . . .   5
     7.2.  OAuth Authorization Server Metadata Registration  . . . .   6
       7.2.1.  Registry Contents . . . . . . . . . . . . . . . . . .   6
     7.3.  OAuth Token Introspection Response  . . . . . . . . . . .   7
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
     8.1.  Cross-JWT Confusion . . . . . . . . . . . . . . . . . . .   7
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
     9.2.  Informative References  . . . . . . . . . . . . . . . . .   9
   Appendix A.  Document History . . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  10

1.  Introduction

   OAuth 2.0 Token Introspection [RFC7662] specifies a method for a
   protected resource to query an OAuth 2.0 authorization server to
   determine the state of an access token and obtain data associated
   with the access token.  This allows deployments to implement
   identifier-based access tokens in an interoperable way.

   The introspection response as specified in OAuth 2.0 Token
   Introspection [RFC7662] is a plain JSON object.  However, there are
   use cases where the resource server requires stronger assurance that
   the authorisation server issued the access token, including cases
   where the authorisation server assumes liability for the token's
   content.  An example is a resource server using verified person data
   to create qualified electronic signatures.

   In such use cases, it would be useful to return a signed JWT as the
   introspection response.  This specification extends the Token
   Introspection endpoint with the capability to return responses as
   JWTs.

2.  Requesting a JWT Response

   A resource server requests to receive a JWT introspection response by
   including an Accept header with content type "application/jwt" in the
   introspection request.



Lodderstedt & Dzhuvinov Expires November 29, 2018               [Page 2]


Internet-Draft                JWT Response                      May 2018


   The following is a non-normative example request:

   POST /introspect HTTP/1.1
   Host: server.example.com
   Accept: application/jwt
   Content-Type: application/x-www-form-urlencoded

   token=2YotnFZFEjr1zCsicMWpAA

3.  JWT Response

   The introspection endpoint responds with a JWT, setting the Content-
   Type header to "application/jwt".

   This JWT MUST contain the claims "iss" and "aud" in order to prevent
   misuse of the JWT as ID or access token (see Section 8.1).

   This JWT may furthermore contain all other claims described in
   Section 2.2. of [RFC7662].

   The following is a non-normative example response (with line breaks
   for display purposes only):

   HTTP/1.1 200 OK
   Content-Type: application/jwt

   eyJraWQiOiIxIiwiYWxnIjoiUlMyNTYifQ.eyJzdWIiOiJaNU8zdXBQQzg4UXJBa
   ngwMGRpcyIsImF1ZCI6Imh0dHBzOlwvXC9wcm90ZWN0ZWQuZXhhbXBsZS5uZXRcL
   3Jlc291cmNlIiwiZXh0ZW5zaW9uX2ZpZWxkIjoidHdlbnR5LXNldmVuIiwic2Nvc
   GUiOiJyZWFkIHdyaXRlIGRvbHBoaW4iLCJpc3MiOiJodHRwczpcL1wvc2VydmVyL
   mV4YW1wbGUuY29tXC8iLCJhY3RpdmUiOnRydWUsImV4cCI6MTQxOTM1NjIzOCwia
   WF0IjoxNDE5MzUwMjM4LCJjbGllbnRfaWQiOiJsMjM4ajMyM2RzLTIzaWo0Iiwid
   XNlcm5hbWUiOiJqZG9lIn0.HEQHf05vqVvWVnWuEjbzUnPz6JDQVR69QkxgzBNq5
   kk-sK54ieg1STazXGsdFAT8nUhiiV1f_Z4HOKNnBs8TLKaFXokhA0MqNBOYI--2u
   nVHDqI_RPmC3p0NmP02Xmv4hzxFmTmpgjSy3vpKQDihOjhwNBh7G81JNaJqjJQTR
   v_1dHUPJotQjMK3k8_5FyiO2p64Y2VyxyQn1VWVlgOHlJwhj6BaGHk4Qf5F8DHQZ
   1WCPg2p_-hwfINfXh1_buSjxyDRF4oe9pKy6ZB3ejh9qIMm-WrwltuU1uWMXxN6e
   S6tUtpKo8UCHBwLWCHmJN7KU6ZojmaISspdS23lELAlyw

   The example response contains the following JSON document:











Lodderstedt & Dzhuvinov Expires November 29, 2018               [Page 3]


Internet-Draft                JWT Response                      May 2018


   {
     "sub": "Z5O3upPC88QrAjx00dis",
     "aud": "https://protected.example.net/resource",
     "scope": "read write dolphin",
     "iss": "https://server.example.com/",
     "active": true,
     "exp": 1419356238,
     "iat": 1419350238,
     "client_id": "l238j323ds-23ij4",
     "given_name": "John",
     "family_name":"Doe",
     "birthdate":"1982-02-01"
   }

4.  Client Metadata

   The authorization server determines what algorithm to employ to
   secure the JWT for a particular introspection response.  This
   decision can be based on registered metadata parameters for the
   resource server, supplied via dynamic client registration with the
   resource server posing as the client.

   The parameter names follow the pattern established by OpenID Connect
   Dynamic Client Registration [OpenID.Registration] for configuring
   signing and encryption algorithms for JWT responses at the UserInfo
   endpoint.

   The following client metadata parameters are introduced by this
   specification:

   introspection_signed_response_alg  JWS [RFC7515] "alg" algorithm JWA
           [RFC7518] REQUIRED for signing introspection responses.  If
           this is specified, the response will be JWT [RFC7519]
           serialized, and signed using JWS.  The default, if omitted,
           is for the introspection response to return the Claims as a
           UTF-8 encoded JSON object using the "application/json"
           content type, as defined in [RFC7662].

   introspection_encrypted_response_alg  JWE [RFC7516] "alg" algorithm
           JWA [RFC7518] REQUIRED for encrypting introspection
           responses.  If both signing and encryption are requested, the
           response will be signed then encrypted, with the result being
           a Nested JWT, as defined in JWT [RFC7519].  The default, if
           omitted, is that no encryption is performed.

   introspection_encrypted_response_enc  JWE [RFC7516] "enc" algorithm
           JWA [RFC7518] REQUIRED for encrypting introspection
           responses.  If "introspection_encrypted_response_alg" is



Lodderstedt & Dzhuvinov Expires November 29, 2018               [Page 4]


Internet-Draft                JWT Response                      May 2018


           specified, the default for this value is A128CBC-HS256.  When
           "introspection_encrypted_response_enc" is included,
           "introspection_encrypted_response_alg" MUST also be provided.

   Resource servers may register their public encryption keys using the
   "jwks_uri" or "jwks" metadata parameters.

5.  Authorization Server Metadata

   Authorization servers SHOULD publish the supported algorithms for
   signing and encrypting the JWT of an introspection response by
   utilizing OAuth Authorization Server Metadata parameters.

   The following parameters are introduced by this specification:

   introspection_signing_alg_values_supported  OPTIONAL.  JSON array
           containing a list of the JWS [RFC7515] signing algorithms
           ("alg" values) JWA [RFC7518] supported by the Introspection
           Endpoint to sign the response.

   introspection_encryption_alg_values_supported  OPTIONAL.  JSON array
           containing a list of the JWE [RFC7516] encryption algorithms
           ("alg" values) JWA [RFC7518] supported by the Introspection
           Endpoint to encrypt the response.

   introspection_encryption_enc_values_supported  OPTIONAL.  JSON array
           containing a list of the JWE [RFC7516] encryption algorithms
           ("enc" values) JWA [RFC7518] supported by the Introspection
           Endpoint to encrypt the response.

6.  Acknowledgements

   We would like to thank Petteri Stenius and Neil Madden for their
   valuable feedback.

7.  IANA Considerations

7.1.  OAuth Dynamic Client Registration Metadata Registration

   This specification requests registration of the following client
   metadata definitions in the IANA "OAuth Dynamic Client Registration
   Metadata" registry [IANA.OAuth.Parameters] established by [RFC7591]:

7.1.1.  Registry Contents

   o  Client Metadata Name: "introspection_signed_response_alg"





Lodderstedt & Dzhuvinov Expires November 29, 2018               [Page 5]


Internet-Draft                JWT Response                      May 2018


   o  Client Metadata Description: String value indicating the client's
      desired introspection response signing algorithm.

   o  Change Controller: IESG

   o  Specification Document(s): Section 4 of [[ this specification ]]

   o  Client Metadata Name: "introspection_encrypted_response_alg"

   o  Client Metadata Description: String value specifying the desired
      introspection response encryption algorithm (alg value).

   o  Change Controller: IESG

   o  Specification Document(s): Section 4 of [[ this specification ]]

   o  Client Metadata Name: "introspection_encrypted_response_enc"

   o  Client Metadata Description: String value specifying the desired
      introspection response encryption algorithm (enc value).

   o  Change Controller: IESG

   o  Specification Document(s): Section 4 of [[ this specification ]]

7.2.  OAuth Authorization Server Metadata Registration

   This specification requests registration of the following value in
   the IANA "OAuth Authorization Server Metadata" registry
   [IANA.OAuth.Parameters] established by [I-D.ietf-oauth-discovery].

7.2.1.  Registry Contents

   o  Metadata Name: "introspection_signing_alg_values_supported"

   o  Metadata Description: JSON array containing a list of algorithms
      supported by the authorization server for introspection response
      signing.

   o  Change Controller: IESG

   o  Specification Document(s): Section 5 of [[ this specification ]]

   o  Metadata Name: "introspection_encryption_alg_values_supported"

   o  Metadata Description: JSON array containing a list of algorithms
      supported by the authorization server for introspection response
      encryption (alg value).



Lodderstedt & Dzhuvinov Expires November 29, 2018               [Page 6]


Internet-Draft                JWT Response                      May 2018


   o  Change Controller: IESG

   o  Specification Document(s): Section 5 of [[ this specification ]]

   o  Metadata Name: "introspection_encryption_enc_values_supported"

   o  Metadata Description: JSON array containing a list of algorithms
      supported by the authorization server for introspection response
      encryption (enc value).

   o  Change Controller: IESG

   o  Specification Document(s): Section 5 of [[ this specification ]]

7.3.  OAuth Token Introspection Response

   TBD: add all OpenID Connect standard claims.

8.  Security Considerations

8.1.  Cross-JWT Confusion

   JWT introspection responses and OpenID Connect ID Tokens are
   syntactically more or less equivalent.  An attacker could therefore
   try to misuse an JWT obtained from an introspection response to
   impersonate the user whose claims are included in this JWT at a
   OpenID Connect RP.  Such an attack is treated and prevented like any
   other token substitution attack.  The AS MUST include the claims
   "iss" and "aud" into every JWT introspection response.  This allows
   every well behaving OpenID Connect RP to detect substitution by
   checking the "iss" and "aud" claims as described in Section 3.1.3.7.
   of [OpenID.Core].  RPs should also use and check the "nonce"
   parameter and claim to prevent token and code replay.

   Resource servers utilizing JWTs to represent structured access tokens
   could be susceptible to replay attacks as well.  Resource servers
   should therefore apply proper counter measures against replay as
   described in [I-D.ietf-oauth-security-topics], section 2.2.

   JWT Confusion and other attacks on JWTs are discussed in detail in
   [I-D.ietf-oauth-jwt-bcp].

9.  References








Lodderstedt & Dzhuvinov Expires November 29, 2018               [Page 7]


Internet-Draft                JWT Response                      May 2018


9.1.  Normative References

   [I-D.ietf-oauth-discovery]
              Jones, M., Sakimura, N., and J. Bradley, "OAuth 2.0
              Authorization Server Metadata", draft-ietf-oauth-
              discovery-10 (work in progress), March 2018.

   [I-D.ietf-oauth-jwt-bcp]
              Sheffer, Y., Hardt, D., and M. Jones, "JSON Web Token Best
              Current Practices", draft-ietf-oauth-jwt-bcp-03 (work in
              progress), May 2018.

   [I-D.ietf-oauth-security-topics]
              Lodderstedt, T., Bradley, J., Labunets, A., and D. Fett,
              "OAuth 2.0 Security Best Current Practice", draft-ietf-
              oauth-security-topics-06 (work in progress), May 2018.

   [OpenID.Core]
              NRI, Ping Identity, Microsoft, Google, and Salesforce,
              "OpenID Connect Core 1.0 incorporating errata set 1", Nov
              2014,
              <http://openid.net/specs/openid-connect-core-1_0.html>.

   [OpenID.Registration]
              NRI, Ping Identity, and Microsoft, "OpenID Connect Dynamic
              Client Registration 1.0 incorporating errata set 1", Nov
              2014, <https://openid.net/specs/
              openid-connect-registration-1_0.html>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC2246]  Dierks, T. and C. Allen, "The TLS Protocol Version 1.0",
              RFC 2246, DOI 10.17487/RFC2246, January 1999,
              <https://www.rfc-editor.org/info/rfc2246>.

   [RFC7515]  Jones, M., Bradley, J., and N. Sakimura, "JSON Web
              Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
              2015, <https://www.rfc-editor.org/info/rfc7515>.

   [RFC7516]  Jones, M. and J. Hildebrand, "JSON Web Encryption (JWE)",
              RFC 7516, DOI 10.17487/RFC7516, May 2015,
              <https://www.rfc-editor.org/info/rfc7516>.






Lodderstedt & Dzhuvinov Expires November 29, 2018               [Page 8]


Internet-Draft                JWT Response                      May 2018


   [RFC7518]  Jones, M., "JSON Web Algorithms (JWA)", RFC 7518,
              DOI 10.17487/RFC7518, May 2015,
              <https://www.rfc-editor.org/info/rfc7518>.

   [RFC7519]  Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
              (JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,
              <https://www.rfc-editor.org/info/rfc7519>.

   [RFC7591]  Richer, J., Ed., Jones, M., Bradley, J., Machulak, M., and
              P. Hunt, "OAuth 2.0 Dynamic Client Registration Protocol",
              RFC 7591, DOI 10.17487/RFC7591, July 2015,
              <https://www.rfc-editor.org/info/rfc7591>.

   [RFC7662]  Richer, J., Ed., "OAuth 2.0 Token Introspection",
              RFC 7662, DOI 10.17487/RFC7662, October 2015,
              <https://www.rfc-editor.org/info/rfc7662>.

9.2.  Informative References

   [IANA.OAuth.Parameters]
              IANA, "OAuth Parameters",
              <http://www.iana.org/assignments/oauth-parameters>.

Appendix A.  Document History

   [[ To be removed from the final specification ]]

   -01

   o  fixed typos in client meta data field names

   o  added OAuth Server Metadata parameters to publish algorithms
      supported for signing and encrypting the introspection response

   o  added registration of new parameters for OAuth Server Metadata and
      Client Registration

   o  added explicit request for JWT introspection response

   o  made iss and aud claims mandatory in introspection response

   o  Stylistic and clarifying edits, updates references

   -00

   o  initial version





Lodderstedt & Dzhuvinov Expires November 29, 2018               [Page 9]


Internet-Draft                JWT Response                      May 2018


Authors' Addresses

   Torsten Lodderstedt (editor)
   YES.com AG

   Email: torsten@lodderstedt.net


   Vladimir Dzhuvinov
   Connect2id Ltd.

   Email: vladimir@connect2id.com







































Lodderstedt & Dzhuvinov Expires November 29, 2018              [Page 10]


Html markup produced by rfcmarkup 1.127, available from https://tools.ietf.org/tools/rfcmarkup/