| OAuth Working Group | J. Richer |
| Internet-Draft | The MITRE Corporation |
| Intended status: Experimental | M. Jones |
| Expires: July 31, 2015 | Microsoft |
| J. Bradley | |
| Ping Identity | |
| M. Machulak | |
| Newcastle University | |
| January 27, 2015 |
OAuth 2.0 Dynamic Client Registration Management Protocol
draft-ietf-oauth-dyn-reg-management-08
This specification defines methods for management of dynamic OAuth 2.0 client registrations for use cases in which the properties of a registered client may need to be changed during the lifetime of the client. Not all authorization servers supporting dynamic client registration will support these management methods.
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This Internet-Draft will expire on July 31, 2015.
Copyright (c) 2015 IETF Trust and the persons identified as the document authors. All rights reserved.
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In order for an OAuth 2.0 client to utilize an OAuth 2.0 authorization server, the client needs specific information to interact with the server, including an OAuth 2.0 client identifier to use at that server. The OAuth 2.0 Dynamic Client Registration Protocol [OAuth.Registration] specification describes how an OAuth 2.0 client can be dynamically registered with an authorization server to obtain this information and how metadata about the client can be registered with the server.
This specification extends the core registration specification by defining a set of methods for management of dynamic OAuth 2.0 client registrations beyond those defined in the core registration specification.
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 [RFC2119].
Unless otherwise noted, all the protocol parameter names and values are case sensitive.
This specification uses the terms "access token", "authorization code", "authorization endpoint", "authorization grant", "authorization server", "client", "client identifier", "client secret", "grant type", "protected resource", "redirection URI", "refresh token", "resource owner", "resource server", "response type", and "token endpoint" defined by OAuth 2.0 [RFC6749] and the terms defined by the OAuth 2.0 Client Dynamic Registration Protocol [OAuth.Registration].
This specification defines the following terms:
This extends the flow in the OAuth 2.0 Dynamic Client Registration Protocol [OAuth.Registration] specification as follows:
+--------(A)- Initial Access Token (OPTIONAL)
|
| +----(B)- Software Statement (OPTIONAL)
| |
v v
+-----------+ +---------------+
| |--(C)- Client Registration Request -->| Client |
| | | Registration |
| |<-(D)- Client Information Response ---| Endpoint |
| | +---------------+
| |
| | +---------------+
| Client or |--(E)- Read or Update Request ------->| |
| Developer | | |
| |<-(F)- Client Information Response ---| Client |
| | | Configuration |
| | | Endpoint |
| | | |
| |--(G)- Delete Request --------------->| |
| | | |
| |<-(H)- Delete Confirmation -----------| |
+-----------+ +---------------+
Figure 1: Abstract Extended Dynamic Client Registration Flow
The abstract OAuth 2.0 client dynamic registration flow illustrated in Figure 1 describes the interaction between the client or developer and the endpoints defined in this specification and its parent. This figure does not demonstrate error conditions. This flow includes the following steps:
The client configuration endpoint is an OAuth 2.0 protected resource that is provisioned by the server to facilitate viewing, updating, and deleting a client's registered information. The location of this endpoint is communicated to the client through the registration_client_uri member of the client information response, as specified in Section 3. The client MUST use its registration access token in all calls to this endpoint as an OAuth 2.0 Bearer Token [RFC6750].
The client configuration endpoint MUST require transport-layer security. The server MUST support TLS 1.2 RFC 5246 [RFC5246] and MAY support additional transport-layer mechanisms meeting its security requirements. When using TLS, the client MUST perform a TLS/SSL server certificate check, per RFC 6125 [RFC6125]. Implementation security considerations can be found in Recommendations for Secure Use of TLS and DTLS [TLS.BCP].
Operations on this endpoint are switched through the use of different HTTP methods [RFC7231]. If an authorization server does not support a particular method on the client configuration endpoint, it MUST respond with the appropriate error code.
To read the current configuration of the client on the authorization server, the client makes an HTTP GET request to the client configuration endpoint, authenticating with its registration access token.
Following is a non-normative example request (with line wraps for display purposes only):
GET /register/s6BhdRkqt3 HTTP/1.1 Accept: application/json Host: server.example.com Authorization: Bearer reg-23410913-abewfq.123483
Upon successful read of the information for a currently active client, the authorization server responds with an HTTP 200 OK with content type of application/json and a payload, as described in Section 3. Some values in the response, including the client_secret and registration_access_token, MAY be different from those in the initial registration response. If the authorization server includes a new client secret and/or registration access token in its response, the client MUST immediately discard its previous client secret and/or registration access token. The value of the client_id MUST NOT change from the initial registration response.
If the registration access token used to make this request is not valid, the server MUST respond with an error as described in OAuth Bearer Token Usage [RFC6750].
If the client does not exist on this server, the server MUST respond with HTTP 401 Unauthorized and the registration access token used to make this request SHOULD be immediately revoked.
If the client does not have permission to read its record, the server MUST return an HTTP 403 Forbidden.
This operation updates a previously-registered client with new metadata at the authorization server. This request is authenticated by the registration access token issued to the client.
The client sends an HTTP PUT to the client configuration endpoint with a content type of application/json. The HTTP entity payload is a JSON [RFC7159] document consisting of a JSON object and all parameters as top- level members of that JSON object.
This request MUST include all client metadata fields as returned to the client from a previous registration, read, or update operation. The client MUST NOT include the registration_access_token, registration_client_uri, client_secret_expires_at, or client_id_issued_at fields described in Section 3.
Valid values of client metadata fields in this request MUST replace, not augment, the values previously associated with this client. Omitted fields MUST be treated as null or empty values by the server, indicating the client's request to delete them from the client's registration. The authorization server MAY ignore any null or empty value in the request just as any other value.
The client MUST include its client_id field in the request, and it MUST be the same as its currently-issued client identifier. If the client includes the client_secret field in the request, the value of this field MUST match the currently-issued client secret for that client. The client MUST NOT be allowed to overwrite its existing client secret with its own chosen value.
For all metadata fields, the authorization server MAY replace any invalid values with suitable default values, and it MUST return any such fields to the client in the response.
For example, a client could send the following request to the client registration endpoint to update the client registration in the above example with new information:
Following is a non-normative example request (with line wraps for display purposes only):
PUT /register/s6BhdRkqt3 HTTP/1.1
Accept: application/json
Host: server.example.com
Authorization: Bearer reg-23410913-abewfq.123483
{
"client_id":"s6BhdRkqt3",
"client_secret": "cf136dc3c1fc93f31185e5885805d",
"redirect_uris":[
"https://client.example.org/callback",
"https://client.example.org/alt"],
"grant_types": ["authorization_code", "refresh_token"],
"token_endpoint_auth_method": "client_secret_basic",
"jwks_uri": "https://client.example.org/my_public_keys.jwks",
"client_name":"My New Example",
"client_name#fr":"Mon Nouvel Exemple",
"logo_uri":"https://client.example.org/newlogo.png",
"logo_uri#fr":"https://client.example.org/fr/newlogo.png"
}
This example uses client metadata values defined in [OAuth.Registration].
Upon successful update, the authorization server responds with an HTTP 200 OK Message with content type application/json and a payload, as described in Section 3. Some values in the response, including the client_secret and registration_access_token, MAY be different from those in the initial registration response. If the authorization server includes a new client secret and/or registration access token in its response, the client MUST immediately discard its previous client secret and/or registration access token. The value of the client_id MUST NOT change from the initial registration response.
If the registration access token used to make this request is not valid, the server MUST respond with an error as described in OAuth Bearer Token Usage [RFC6750].
If the client does not exist on this server, the server MUST respond with HTTP 401 Unauthorized, and the registration access token used to make this request SHOULD be immediately revoked.
If the client is not allowed to update its records, the server MUST respond with HTTP 403 Forbidden.
If the client attempts to set an invalid metadata field and the authorization server does not set a default value, the authorization server responds with an error as described in [OAuth.Registration].
To deprovision itself on the authorization server, the client makes an HTTP DELETE request to the client configuration endpoint. This request is authenticated by the registration access token issued to the client as described in [RFC6749].
Following is a non-normative example request (with line wraps for display purposes only):
DELETE /register/s6BhdRkqt3 HTTP/1.1 Host: server.example.com Authorization: Bearer reg-23410913-abewfq.123483
A successful delete action will invalidate the client_id, client_secret, and registration_access_token for this client, thereby preventing the client_id from being used at either the authorization endpoint or token endpoint of the authorization server. If possible, the authorization server SHOULD immediately invalidate all existing authorization grants and currently-active access tokens, refresh tokens, and other tokens associated with this client.
If a client has been successfully deprovisioned, the authorization server MUST respond with an HTTP 204 No Content message.
If the server does not support the delete method, the server MUST respond with an HTTP 405 Not Supported.
If the registration access token used to make this request is not valid, the server MUST respond with an error as described in OAuth Bearer Token Usage [RFC6750].
If the client does not exist on this server, the server MUST respond with HTTP 401 Unauthorized and the registration access token used to make this request SHOULD be immediately revoked.
If the client is not allowed to delete itself, the server MUST respond with HTTP 403 Forbidden.
Following is a non-normative example response:
HTTP/1.1 204 No Content Cache-Control: no-store Pragma: no-cache
This specification extends the client information response defined in OAuth 2.0 Client Dynamic Registration [OAuth.Registration], which states that the response contains the client identifier as well as the client secret, if the client is a confidential client. When used with this specification, the client information response also contains the fully qualified URL of the client configuration endpoint [ClientConfigEndpoint] for this specific client that the client or developer may use to manage the client's registration configuration, as well as a registration access token that is to be used by the client or developer to perform subsequent operations at the client configuration endpoint.
Additionally, the authorization server MUST return all registered metadata about this client, including any fields provisioned by the authorization server itself. The authorization server MAY reject or replace any of the client's requested metadata values submitted during the registration or update requests and substitute them with suitable values.
The response is an application/json document with all parameters as top-level members of a JSON object [RFC7159].
Following is a non-normative example response:
HTTP/1.1 200 OK
Content-Type: application/json
Cache-Control: no-store
Pragma: no-cache
{
"registration_access_token": "reg-23410913-abewfq.123483",
"registration_client_uri":
"https://server.example.com/register/s6BhdRkqt3",
"client_id":"s6BhdRkqt3",
"client_secret": "cf136dc3c1fc93f31185e5885805d",
"client_id_issued_at":2893256800,
"client_secret_expires_at":2893276800,
"client_name":"My Example Client",
"client_name#ja-Jpan-JP":
"\u30AF\u30E9\u30A4\u30A2\u30F3\u30C8\u540D",
"redirect_uris":[
"https://client.example.org/callback",
"https://client.example.org/callback2"],
"grant_types": ["authorization_code", "refresh_token"],
"token_endpoint_auth_method": "client_secret_basic",
"logo_uri": "https://client.example.org/logo.png",
"jwks_uri": "https://client.example.org/my_public_keys.jwks"
}
This specification requests that IANA extend the OAuth Dynamic Client Metadata registry with the following entries:
While the client secret can expire, the registration access token SHOULD NOT expire while a client is still actively registered. If this token were to expire, a developer or client could be left in a situation where they have no means of retrieving or updating the client's registration information. Were that the case, a new registration would be required, thereby generating a new client identifier. However, to limit the exposure surface of the registration access token, the registration access token MAY be rotated when the developer or client does a read or update operation on the client's client configuration endpoint. As the registration access tokens are relatively long-term credentials, and since the registration access token is a Bearer token and acts as the sole authentication for use at the client configuration endpoint, it MUST be protected by the developer or client as described in OAuth 2.0 Bearer Token Usage [RFC6750].
Since requests to the client configuration endpoint result in the transmission of clear-text credentials (in the HTTP request and response), the authorization server MUST require the use of a transport-layer security mechanism when sending requests to the endpoint. The server MUST support TLS 1.2 RFC 5246 [RFC5246] and MAY support additional transport-layer mechanisms meeting its security requirements. When using TLS, the client MUST perform a TLS/SSL server certificate check, per RFC 6125 [RFC6125]. Implementation security considerations can be found in Recommendations for Secure Use of TLS and DTLS [TLS.BCP].
Since the client configuration endpoint is an OAuth 2.0 protected resource, it SHOULD have some rate limiting on failures to prevent the registration access token from being disclosed though repeated access attempts.
If a client is deprovisioned from a server, any outstanding registration access token for that client MUST be invalidated at the same time. Otherwise, this can lead to an inconsistent state wherein a client could make requests to the client configuration endpoint where the authentication would succeed but the action would fail because the client is no longer valid. To prevent accidental disclosure from such an erroneous situation, the authorization server MUST treat all such requests as if the registration access token was invalid (by returning an HTTP 401 Unauthorized error, as described).
The authors thank the OAuth Working Group, the User-Managed Access Working Group, and the OpenID Connect Working Group participants for their input to this document. In particular, the following individuals have been instrumental in their review and contribution to various versions of this document: Amanda Anganes, Derek Atkins, Tim Bray, Domenico Catalano, Donald Coffin, Vladimir Dzhuvinov, George Fletcher, Thomas Hardjono, Phil Hunt, William Kim, Torsten Lodderstedt, Eve Maler, Josh Mandel, Nov Matake, Tony Nadalin, Nat Sakimura, Christian Scholz, and Hannes Tschofenig.
Throughout the course of the dynamic registration protocol, there are three different classes of credentials in play, each with different properties and targets.
The authorization server may be configured to issue new registration access token and/or client credentials (such as a client_secret) throughout the lifetime of the client. This map help minimize the impact of exposed credentials. The authorization server conveys new registration access tokens and client credentials (if applicable) to the client in the client information response of either a read or update request to the client configuration endpoint. The client's current registration access token and client credentials (if applicable) MUST be included in the client information response.
The registration access token SHOULD be rotated only in response to a read or update request to the client configuration endpoint, at which point the new registration access token is returned to the client and the old registration access token MUST be discarded by the client and SHOULD be discarded by the server, if possible. If instead the registration access token were to expire or be invalidated outside of such requests, the client or developer might be locked out of managing the client's configuration.
Note that the authorization server decides the frequency of the credential rotation and not the client. Methods by which the client can request credential rotation are outside the scope of this document.
The authorization server MUST provide the client with the fully qualified URL in the registration_client_uri element of the Client Information Response, as specified in Section 3. The authorization server MUST NOT expect the client to construct or discover this URL on its own. The client MUST use the URL as given by the server and MUST NOT construct this URL from component pieces.
Depending on deployment characteristics, the client configuration endpoint URL may take any number of forms. It is RECOMMENDED that this endpoint URL be formed through the use of a server-constructed URL string which combines the client registration endpoint's URL and the issued client_id for this client, with the latter as either a path parameter or a query parameter. For example, a client with the client identifier s6BhdRkqt3 could be given a client configuration endpoint URL of https://server.example.com/register/s6BhdRkqt3 (path parameter) or of https://server.example.com/register?client_id=s6BhdRkqt3 (query parameter). In both of these cases, the client simply uses the URL as given by the authorization server.
These common patterns can help the server to more easily determine the client to which the request pertains, which MUST be matched against the client to which the registration access token was issued. If desired, the server MAY simply return the client registration endpoint URL as the client configuration endpoint URL and change behavior based on the authentication context provided by the registration access token.
[[ to be removed by the RFC editor before publication as an RFC ]]
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