Internet-Draft | The Grant Negotiation and Authorization Protocol - Advanced Features | August 2020 |
Hardt | Expires 16 February 2021 | [Page] |
- Workgroup:
- Network Working Group
- Internet-Draft:
- draft-hardt-gnap-advanced-01
- Published:
- Intended Status:
- Standards Track
- Expires:
The Grant Negotiation and Authorization Protocol - Advanced Features
Abstract
TBD¶
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 16 February 2021.¶
Copyright Notice
Copyright (c) 2020 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.¶
1. Introduction
This document includes additional features for the Grant Negotiation and Authorization Protocol (GNAP) [GNAP], and presumes familiarity and knowledge of GNAP.¶
Terminology¶
This document uses the following terms defined in [GNAP]:¶
- authN¶
- authZ¶
- Access¶
- Access URI¶
- Claim¶
- Grant Client (GC)¶
- Registered Client¶
- Grant¶
- Grant Server (GS)¶
- Grant URI¶
- Grant Request¶
- Grant Response¶
- GS URI¶
- Interaction¶
- NumericDate¶
- Resource Owner (RO)¶
- Resource Server (RS)¶
- User¶
Notational Conventions¶
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this specification are to be interpreted as described in [RFC2119].¶
Certain security-related terms are to be understood in the sense defined in [RFC4949]. These terms include, but are not limited to, "attack", "authentication", "authorization", "certificate", "confidentiality", "credential", "encryption", "identity", "sign", "signature", "trust", "validate", and "verify".¶
Unless otherwise noted, all the protocol parameter names and values are case sensitive.¶
Some protocol parameters are parts of a JSON document, and are referred to in JavaScript notation. For example, foo.bar refers to the "bar" boolean attribute in the "foo" object in the following example JSON document:¶
{ "foo" : { "bar": true } }¶
2. Grant Management APIs
In addition to creating and reading a Grant as specified in GNAP The GC MAY list, update, delete, and discover a Grant.¶
2.1. List Grants
The GC MAY list the Grants provided to the GC by doing an a GET on the GS URI. The GS MUST respond with a list of Grant URIs [ format TBD] or one of the following errors:¶
- TBD¶
2.2. Update Grant
The GC updates a Grant by doing an HTTP PUT of a JSON document to the corresponding Grant URI.¶
The JSON document MUST include the following from the [GNAP] Grant Request JSON:¶
and MAY include the following from the [GNAP] Grant Request JSON:¶
The GS MUST respond with one of the standard GNAP responses (Grant Response, Interaction Response, Wait Response) or one of the following errors:¶
- TBD¶
from Error Responses Section 8.¶
Following is a non-normative example where the GC wants to update the Grant Request with additional claims:¶
{ "iat" : 15790460234, "uri" : "https://as.example/endpoint/grant/example3", "claims": { "oidc": { "userinfo" : { "email" : { "essential" : true }, "name" : { "essential" : true }, "picture" : null } } } }¶
2.3. Delete Grant
The GC deletes a Grant by doing an HTTP DELETE of the corresponding Grant URI.¶
The GS MUST respond with OK 200, or one of the following errors:¶
- TBD¶
4. Reciprocal Grant
Party A and Party B both want to obtain a Grant from the other party. Each party will be both Grant Client and Grant Server. This would require two complete GNAP flows with an awkward redirect between them, and the User may have to authenticate multiple times as context is lost. Reciprocal Grant simplifies the User experience.¶
In the following sequence, steps 1 - 7 & 9 are a standard GNAP sequence.¶
Party A Party B +--------+ +--------+ | | | | | Client |--(1)-- Create Grant A ->| GS | | | | | | Client |<--- Interaction ---(2)--| GS | | | Response | | | | | | | Client |--(3)--- Read Grant A -->| GS | +---+ | | | | | U | | Client |--(4)--- Interaction --- | - - - | ----->| s | | | Transfer | | | e | | | | GS |<-(5)->| r | | | | | authN | | | | | GS |<-(6)->| | | | | | authZ | | | Client |<------- Grant A ---(7)--| GS | +---+ | | Response | | | | | | | GS |<- Create Grant B --(8)--| Client | +---+ | | user.reciprocal | | | U | | | | | | s |<------ | - - - | --- Interaction --(9)---| GS | | e | | | Transfer | | | r |<-(10)->| GS | | | | | AuthZ | | | | +---+ | GS |--(11)-- Grant B ------->| Client | | | Response | | +--------+ +--------+ Client = Grant Client¶
- Create Grant A Party A makes a Create Grant request to the Party B GS URI.¶
- Interaction Response Party B returns an interaction response containing the Grant A URI.¶
- Read Grant A Party A does an HTTP GET of the Grant A URI.¶
- Interaction Transfer Party A transfers User interaction to the Party B.¶
- User Authentication Party B authenticates the User.¶
- User Authorization If required, Party B interacts with the User to determine which identity claims and/or authorizations in the Grant A Request are to be granted.¶
- Create GrantB Party B creates its Grant B Request with user.reciprocal set to the Grant A URI that will be in the step (2) Grant A Response, and sends it with an HTTP POST to the Party A GS URI. This enables Party A to correlate the Grant B Request and its Grant and the User.¶
- Grant S Response Party B responds to Party A's Create Grant A Request with a Grant A Response.¶
- Interaction Transfer Party B redirects the User to the Completion URI at Party A.¶
- User Authorization If required, Party A interacts with the User to determine which identity claims and/or authorizations in Party B's Grant B Request are to be granted.¶
- Grant B Response Party A responds with the Grant B Response.¶
5. GS Initiated Grant
The User is at the GS, and wants to interact with a Registered Client. The GC has previously configured an initiation_uri at the GS, and the Grant it requires.¶
In this sequence, the GS creates a Grant and redirects the User to the GC's initiation_uri passing a Grant URI:¶
+--------+ +-------+ +------+ | GC | | GS | | User | | | | |<--(1)-->| | | | | | | | | |<----- GS Initiation Redirect --- | - - - | --(2)---| | | (3) | | | | | | verify |--(4)--- Read Grant ------------->| | +------+ | | | | | |<--------- Grant Response --(5)---| | | | | | +--------+ +-------+¶
- User Interaction The GS interacts with the User to determine the GC and what identity claims and / or authorizations to provide. The GS creates a Grant and corresponding Grant URI.¶
- GS Initiated Redirect The GS redirects the User to the GC's initiation_uri, adding a query parameter with the name "grant_uri" and the value being the URL encoded Grant URI.¶
- Client Verification The GC verifies the Grant URI starts with a GS URI from a GS the GC trusts.¶
- Read Grant The GC does an HTTP GET of the Grant URI.¶
- Grant Response The GS responds with a Grant Response.¶
- initiation_uri - a URI at the GC that contains no query or fragment. How the GS learns the GC initiation_uri and require Grant is out of scope of this document.¶
6. User Exists
The GC may want to provide a different experience to the User depending on if a User already exists at the GS. By including one or more identifiers in the Grant Request user.identifiers object, and setting user.exists to true, the GS MAY include a user.exists attribute in a GNAP Interaction Response. The value is true if the GS has a user with one or more of the GC provided identifers, and false if not.¶
- exists - a new attribute of the "user" object. If present in a GNAP Grant Request, it MUST be set to true.¶
A GS indicates support for this feature by returning the features.user_exists attribute in the GS Options response set to true.¶
7. Multiple Interactions
There are situations where the GC can not, or prefers not, to ask for all identity claims and/or authorizations it requires.¶
In this example sequence, the GC requests an identity claim to determine who the User is. Once the GC learns who the User is, the GC updates the Grant for additional identity claims which the GS prompts the User for and returns to the GC. Once those additional claims are received, the GC updates the Grant with the remaining identity claims required.¶
+--------+ +-------+ | Client | | GS | | |--(1)--- Create Grant ----------->| | | | multi = true | | | | | | | |<--- Interaction Response ---(2)--| | | | multi = true | | | | | | | |--(3)--- Read Grant ------------->| | +------+ | | | | | User | | |--(4)--- Interaction Transfer --- | - - - | ------->| | | | | | | | | | | |<--(5)-->| | | | | | authN | | | |<--------- Grant Response ---(6)--| | | | | (7) | | | | | | eval |--(8)--- Update Grant ----------->| | | | | | multi = true | |<--(9)-->| | | | | | authZ | | | |<--------- Grant Response --(10)--| | | | | | multi = true | | | (11) | | | | | | eval |--(12)-- Update Grant ----------->| | | | | | multi = false | |<--(13)->| | | | | | authZ | | | | | | | | | |<--- Interaction Transfer --(14)- | - - - | --------| | | | | | | | | |<--------- Grant Response --(15)--| | +------+ | | multi = false | | | | | | +--------+ +-------+ Client = Grant Client¶
- Create Grant The GC creates a Grant Request (CreateGrant) including an identity claim and interaction.global.multi set to true, and sends it with an HTTP POST to the GS GS URI.¶
- Interaction Response The GS sends an Interaction Response containing the Grant URI and an interaction object, and interaction.global.multi set to true.¶
- Read Grant The GC does an HTTP GET of the Grant URI.¶
- Interaction Transfer The GC transfers User interaction to the GS.¶
- User Authentication The GS authenticates the User.¶
- Grant Response The GS responds with a Grant Response including the identity claim from User authentication and interaction.global.multi set to true.¶
- Grant Evaluation The GC queries its User database and does not find a User record matching the identity claim.¶
- Update Grant The GC creates an Update Grant Request Section 2.2 including the initial identity claims required and interaction.global.multi set to true, and sends it with an HTTP PUT to the Grant URI.¶
- User AuthN The GS interacts with the User to determine which identity claims in the Update Grant Request are to be granted.¶
- Grant Response The GS responds with a Grant Response including the identity claims released by the User and interaction.global.multi set to true.¶
- Grant Evaluation The GC evaluates the identity claims in the Grant Response and determines the remaining User identity claim required.¶
- Update Grant The GC creates an Update Grant Request Section 2.2 including the remaining required identity claims and interaction.global.multi set to false, and sends it with an HTTP PUT to the Grant URI.¶
- User AuthZ The GS interacts with the User to determine which identity claims in the Update Grant Request are to be granted.¶
- Interaction Transfer The GS transfers User interaction to the GC.¶
- Grant Response The GS responds with a Grant Response including the identity claims released by the User and interaction.global.multi set to false.¶
- multi - a new boolean attribute of the GNAP interaction.global object.¶
A GS indicates support for this feature by returning the features.interaction_multi attribute in the GS Options response set to true.¶
8. Error Responses
- TBD¶
9. Acknowledgments
TBD¶
12. Normative References
- [RFC2119]
- Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/info/rfc2119>.
- [RFC4949]
- Shirey, R., "Internet Security Glossary, Version 2", FYI 36, RFC 4949, DOI 10.17487/RFC4949, , <https://www.rfc-editor.org/info/rfc4949>.
- [GNAP]
- Hardt, D., "The Grant Negotiation and Authorization Protocol", , <https://tools.ietf.org/html/draft-hardt-xauth-protocol>.
Appendix A. Document History
A.1. draft-hardt-gnap-advanced-00
- Initial version¶
Appendix B. GS API Table
Below is a consolidated table of GS APIs from [GNAP] and this document:¶
request | http method | uri | response |
---|---|---|---|
Create Grant | POST | GS URI | interaction, wait, or Grant |
List Grants | GET | GS URI | Grant list |
Verify Grant | PATCH | Grant URI | Grant |
Read Grant | GET | Grant URI | wait, or grant |
Update Grant | PUT | Grant URI | Interaction, wait, or Grant |
Delete Grant | DELETE | Grant URI | success |
Read Access | GET | Access URI | Access |
Update Access | PUT | Access URI | Access |
Delete Access | DELETE | Access URI | success |
GS Options | OPTIONS | GS URI | metadata |
Grant Options | OPTIONS | Grant URI | metadata |
Access Options | OPTIONS | Access URI | metadata |