Network Working Group D. Hardt Internet-Draft Amazon Intended status: Informational January 16, 2018 Expires: July 20, 2018 Reciprocal OAuth draft-hardt-oauth-mutual-02 Abstract There are times when a user has a pair of protected resources that would like to request access to each other. While OAuth flows typically enable the user to grant a client access to a protected resource, granting the inverse access requires an additional flow. Reciprocal OAuth enables a more seemless experience for the user to grant access to a pair of protected resources. 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/. 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Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of Hardt Expires July 20, 2018 [Page 1] Internet-Draft I-D January 2018 the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. 1. Introduction In the usual three legged, authorization code grant, the OAuth flow enables a resource owner (user) to enable a client (party A) to be granted authorization to access a protected resource (party B). If party A also has a protected resource that the user would like to let party B access, then a complete OAuth flow, but in the reverse direction, must be performed. Reciprocal OAuth enables party A to obtain constent from the user to grant access to a protected resource at party A, and to short circuit the OAuth flow by passing an authorization code to party B using the acces token party A obtained from party B to provide party B the context of the user. This simplifies the user experience for each party to obtain acces tokens from the other. 1.1. Terminology In this document, the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as described in BCP 14, RFC 2119 [RFC2119]. 2. Reciprocal Authorization Flow The reciprocal authorization flow starts after the client (party A) has obtained an access token from the authorization server (party B) per [RFC6749] 4.1 Authorization Code Grant. 2.1. User Consent Party A obtains consent from the user to grant access to protected resources at party A. The consent represents the scopes party B had preconfigured at party A. 2.2. Reciprocal Authorization Code Party A generates an authorization code representing the access granted to party B by the user. Party A then makes a request to party B's token endpoint authenticating per [RFC6749] 2.3 and sending the following parameters using the "application/x-www-form- urlencoded" format per [RFC6749] Appendix B with a character encoding of UTF-8 in the HTTP request entity-body: Hardt Expires July 20, 2018 [Page 2] Internet-Draft I-D January 2018 grant_type REQUIRED. Value MUST be set to "urn:ietf:params:oauth:grant-type:reciprocal". code REQUIRED. The authorization code generated by party A. client_id REQUIRED, party A'a client ID. access_token REQUIRED, the access token obtained from Party B. Used to provide user context. [DH: security concern passing the access token in the body?] For example, the client makes the following HTTP request using TLS (with extra line breaks for display purposes only): POST /token HTTP/1.1 Host: server.example.com Authorization: Basic ej4hsyfishwssjdusisdhkjsdksusdhjkjsdjk Content-Type: application/x-www-form-urlencoded grant_type=urn%3Aietf%3Aparams%3Aoauth%3Agrant-type%3reciprocal&code=hasdyubasdjahsbdkjbasd&client_id=example.com&access_token=sadadojsadlkjasdkljxxlkjdas Party B MUST then verify the access token was granted to the client identified by the client_id. Party B MUST respond with either an HTTP 200 (OK) response if the request is valid, or an HTTP 400 "Bad Request" if it is not. Party B then plays the role of the client to make an access token request per [RFC6749] 4.1.3. 3. IANA Considerations TBD. 4. Acknowledgements TBD. 5. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC6749] Hardt, D., Ed., "The OAuth 2.0 Authorization Framework", RFC 6749, DOI 10.17487/RFC6749, October 2012, . Hardt Expires July 20, 2018 [Page 3] Internet-Draft I-D January 2018 [RFC6750] Jones, M. and D. Hardt, "The OAuth 2.0 Authorization Framework: Bearer Token Usage", RFC 6750, DOI 10.17487/RFC6750, October 2012, . Appendix A. Document History A.1. draft-hardt-oauth-mutual-00 o Initial version. A.2. draft-hardt-oauth-mutual-01 o renamed to Reciprocal OAuth o clarified user consent in reciprocal flow o changed authentication to be client authentication per [RFC6749] 2.3 A.3. draft-hardt-oauth-mutual-02 o changed grant type to URI o added valid request response codes in 2.2 Author's Address Dick Hardt Amazon Email: dick.hardt@gmail.com Hardt Expires July 20, 2018 [Page 4]