Internet Engineering Task Force N. Sakimura, Ed. Internet-Draft Nomura Research Institute Intended status: Standards Track J. Bradley Expires: May 10, 2013 Ping Identity November 6, 2012 Request by JWS ver.1.0 for OAuth 2.0 draft-sakimura-oauth-requrl-03 Abstract The authorization request in OAuth 2.0 utilizes query parameter serizalization. This specification defines the authorization request using JWT serialization. The request is sent thorugh 'request' parameter or by reference through 'request_url' that points to the JWT, allowing the request to be optionally signed and encrypted. 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/. 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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 Sakimura & Bradley Expires May 10, 2013 [Page 1] Internet-Draft oauth-json-request November 2012 described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Requirements Language . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Authorization Request Object . . . . . . . . . . . . . . . . . 4 4. Authorization Request . . . . . . . . . . . . . . . . . . . . . 5 5. Authorization Server Response . . . . . . . . . . . . . . . . . 7 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 7. Security Considerations . . . . . . . . . . . . . . . . . . . . 7 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8 9.1. Normative References . . . . . . . . . . . . . . . . . . . 8 9.2. Informative References . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9 Sakimura & Bradley Expires May 10, 2013 [Page 2] Internet-Draft oauth-json-request November 2012 1. Introduction The parameters 'request' and 'request_url' are introduced as additional authorization request parameters for the OAuth 2.0 [RFC6749] flows. The 'request' parameter is a JSON Web Token (JWT) [JWT] whose body holds the JSON encoded OAuth 2.0 authorization request parameters. The [JWT] can be passed to the authorization endpoint by reference, in which case the parameter 'request_uri' is used instead of the 'request'. Using [JWT] as the request encoding instead of query parameters has several advantages: 1. The request may be signed so that integrity check may be implemented. If a suitable algorithm is used for the signing, then non-repudiation property may be obtained in addition. 2. The request may be encrypted so that end-to-end confidentiality may be obtained even if in the case TLS connection is terminated at a gateway or a similar device. There are a few cases that request by reference is useful such as: 1. When it is detected that the User Agent dose't suport long URLs - It is entirely possible that some extensions may extend the URL. For example, the client might want to send a public key with the request. 2. Static signature: The client may make a signed request file and put it on the client. This may just be done by a client utility or other process, so that the private key does not have to reside on the client, simplifying programming. 3. When the server wants the requests to be cacheable - The request_uri may include a sha256 hash of the file, as defined in FIPS180-2 [FIPS180-2], the server knows if the file has changed without fetching it, so it does not have to re-fetch a same file, which is a win as well. 4. When the client wants to simplify the implementation without compromising the security. If the request parameters go through the Browser, they may be tampered in the browser even if TLS was used. This implies we need to have signature on the request as well. However, if HTTPS request_url was used, it is not going to be tampered, thus we now do not have to sign the request. This simplifies the implementation. This capability is in use by OpenID Connect. Sakimura & Bradley Expires May 10, 2013 [Page 3] Internet-Draft oauth-json-request November 2012 1.1. 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]. 2. Terminology Following parameters are defined as a request and response parameter. request object A [JWT] that holds OAuth 2.0 authorization requests as JSON object in its body. It MAY include all the potential variables including extension and non-oauth variables. Request object can optionally be digitally signed or signed and encrypted. To sign, [JWS] is used. To encrypt, [JWE] is used. request_uri The absolute URL from which the request object is obtained. Request File This is a physical or logical file that the 'request_url' points to. 3. Authorization Request Object The Authorization Request object is used to provide authorization request parameters. It contains OAuth 2.0 authorization request parameters including extension parameters. It is a JSON Web Signature (JWS) [JWS] signed JWT [JWT] that has the JSON object that holds the OAuth 2.0 authorization request parameters. The parameters are included as the top level members of JSON [RFC4627]. Parameter names and string values are included as JSON strings. Numerical values are included as JSON numbers. It MAY include any extension parameters. This JSON [RFC4627] constitues the body of the [JWT]. The Authorization Request Object MAY be signed or unsigned (plaintext). When it is plaintext, this is indicated by use of the "none" algorithm [JWA] in the JWS header. If signed, the Authorization Request Object SHOULD contain the Claims "iss" (issuer) and "aud" (audience) as members, with their semantics being the same as defined in the JWT [JWT] specification. The Authorization Request Object MAY also be encrypted using JWE [JWE] after signing, with nesting performed in the same manner as specified for JWTs [JWT]. The Authorization Request Object MAY alternatively be sent by reference using "request_uri" parameter. Sakimura & Bradley Expires May 10, 2013 [Page 4] Internet-Draft oauth-json-request November 2012 OAuth 2.0 Authorization Request parameters that are not included in the Authorization Request Object MAY be sent as a query parameter. If the parameter exists both in the query string and the Authorization Request Object, they MUST exactly match. If a required parameter is not present in neither the query parameter or the Authorization Request Object, it forms a malformed request. Following is the example of the JSON which consitutes the body of the [JWT]. { "redirect_url":"https://example.com/rp/endpoint_url", "cliend_id":"http://example.com/rp/" } The following is a non-normative example of a [JWT] encoded authorization request object. It includes extension variables such as "nonce", "userinfo", and "id_token". Note that the line wraps within the values are for display purpose only: JWT algorithm = HS256 HMAC HASH Key = 'aaa' JSON Encoded Header = "{"alg":"HS256","typ":"JWT"}" JSON Encoded Payload = "{"response_type":"code id_token", "client_id":"s6BhdRkqt3", "redirect_uri":"https://client.example.com/cb", "scope":"openid profile", "state":"af0ifjsldkj", "nonce":"n-0S6_WzA2Mj", "userinfo":{"claims":{"name":null,"nickname":{"optional":true}, "email":null,"verified":null, "picture":{"optional":true}},"format":"signed"}, "id_token":{"max_age":86400,"iso29115":"2"}}" JWT = eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJyZXNwb25zZV90eXBlIjoiY29kZ SBpZF90b2tlbiIsImNsaWVudF9pZCI6InM2QmhkUmtxdDMiLCJyZWRpcmVjdF91cmkiO iJodHRwczpcL1wvY2xpZW50LmV4YW1wbGUuY29tXC9jYiIsInNjb3BlIjoib3BlbmlkI HByb2ZpbGUiLCJzdGF0ZSI6ImFmMGlmanNsZGtqIiwidXNlcmluZm8iOnsiY2xhaW1zI jp7Im5hbWUiOm51bGwsIm5pY2tuYW1lIjp7Im9wdGlvbmFsIjp0cnVlfSwiZW1haWwiO m51bGwsInZlcmlmaWVkIjpudWxsLCJwaWN0dXJlIjp7Im9wdGlvbmFsIjp0cnVlfX0sI mZvcm1hdCI6InNpZ25lZCJ9LCJpZF90b2tlbiI6eyJtYXhfYWdlIjo4NjQwMCwiaXNvM jkxMTUiOiIyIn19.2OiqRgrbrHkA1FZ5p_7bc_RSdTbH-wo_Agk-ZRpD3wY 4. Authorization Request The client constructs the request URI by adding the following Sakimura & Bradley Expires May 10, 2013 [Page 5] Internet-Draft oauth-json-request November 2012 parameters to the query component of the authorization endpoint URI using the "application/x-www-form-urlencoded" format: request REQUIRED unless "request_uri" is specified. The authorization request object (Section 3) that holds authorization request parameters stated in the section 4 of OAuth 2.0 [RFC6749]. request_uri REQUIRED unless "request" is specified. The absolute URL that points to the authorization request object (Section 3) that holds authorization request parameters stated in the section 4 of OAuth 2.0 [RFC6749]. When sending the request by "request_uri", the client MAY provide the sha256 hash as defined in FIPS180-2 [FIPS180-2]of the Request File as the fragment to it to assist the cache utilization decision of the Authorization Server. state RECOMMENDED. An opaque value used by the client to maintain state between the request and callback. The authorization server includes this value when redirecting the user-agent back to the client. The parameter SHOULD be used for preventing cross-site request forgery as described in Section 10.12. of OAuth 2.0 [RFC6749] The client directs the resource owner to the constructed URI using an HTTP redirection response, or by other means available to it via the user-agent. For example, the client directs the end-user's user-agent to make the following HTTPS request (line breaks are for display purposes only): GET /authorize?request_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb HTTP/1.1 Host: server.example.com The autorization request object MAY be signed AND/OR encrypted. Upon receipt of "request_uri" in the request, the authorization server MUST send a GET request to the "request_uri" to retrieve the authorization request object unless it is already cached at the Authorization Server. If the response was signed AND/OR encrypted, it has to be decoded accordingly before being processed. Then, the Authorization Server MUST reconstruct the complete client request from the original HTTP request and the content of the request object. Then, the process continues as described in Section 3 of OAuth 2.0 [RFC6749] . Sakimura & Bradley Expires May 10, 2013 [Page 6] Internet-Draft oauth-json-request November 2012 5. Authorization Server Response Authorization Server Response is created and sent to the client as in Section 4 of OAuth 2.0 [RFC6749] . In addition, this document defines additional 'error' values as follows: o "invalid_request_uri" - The provided request_uri was not available. o "invalid_request_format" - The Request Object format was invalid. o "invalid_request_params" - The parameter set provided in the Request Object was invalid. 6. IANA Considerations This document registers following error strings to the OAuth Error Registry. o "invalid_request_uri" - The provided request_uri was not available. o "invalid_request_format" - The Request Object format was invalid. o "invalid_request_params" - The parameter set provided in the Request Object was invalid. 7. Security Considerations In addition to the all the security considerations discussed in OAuth 2.0 [RFC6749], the following security considerations SHOULD be taken into account. When sending the authorization request object through "request" parameter, it SHOULD be signed with [JWS]. When obtaining the Request FIle, the Authorization Server SHOULD use either HTTP over TLS 1.2 as defined in RFC5246 [RFC5246] AND/OR [JWS]. If the request object contains personally identifiable or sensitive information, the "request_uri" MUST be of one-time use and MUST have large enough entropy deemed necessary with applicable security policy. For higher security requirement, using [JWE] is strongly Sakimura & Bradley Expires May 10, 2013 [Page 7] Internet-Draft oauth-json-request November 2012 recommended. [[ToDo]] 8. Acknowledgements Following people contributed to creating this document through the OpenID Connect 1.0 [openid_ab] . Breno de Medeiros (Google), Hideki Nara (TACT), John Bradley (Ping Identity) , Nat Sakimura (NRI) , Ryo Itou (Yahoo! Japan), George Fletcher (AOL), Justin Richer (Mitre), Edmund Jay (MGI1), (add yourself). In addition following people contributed to this and previous versions through The OAuth Working Group. David Recordon (Facebook), Luke Shepard (Facebook), James H. Manger (Telstra), Marius Scurtescu (Google), John Panzer (Google), Dirk Balfanz (Google), (add yourself). 9. References 9.1. Normative References [FIPS180-2] U.S. Department of Commerce and National Institute of Standards and Technology, "Secure Hash Signature Standard", FIPS 180-2, August 2002. Defines Secure Hash Algorithm 256 (SHA256) [JWA] Jones, M., "JSON Web Algorithms (JWA)", March 2011. [JWE] Jones, M., "JSON Web Encryption (JWE)", March 2011. [JWS] Jones, M., Balfanz, D., Bradley, J., Goland, Y., Panzer, J., Sakimura, N., and P. Tarjan, "JSON Web Signature (JWS)", April 2011. [JWT] Jones, M., Balfanz, D., Bradley, J., Goland, Y., Panzer, J., Sakimura, N., and P. Tarjan, "JSON Web Token", July 2011. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. Sakimura & Bradley Expires May 10, 2013 [Page 8] Internet-Draft oauth-json-request November 2012 [RFC4627] Crockford, D., "The application/json Media Type for JavaScript Object Notation (JSON)", RFC 4627, July 2006. [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, August 2008. [RFC6749] Hardt, D., "The OAuth 2.0 Authorization Framework", RFC 6749, October 2012. 9.2. Informative References [openid_ab] openid-specs-ab@openid.net, "OpenID Connect 1.0", October 2011. Authors' Addresses Nat Sakimura (editor) Nomura Research Institute 1-6-5 Marunouchi, Marunouchi Kitaguchi Bldg. Chiyoda-ku, Tokyo 100-0005 Japan Phone: +81-3-5533-2111 Email: n-sakimura@nri.co.jp John Bradley Ping Identity Email: ve7jtb@ve7jtb.com Sakimura & Bradley Expires May 10, 2013 [Page 9]