OAuth Working Group J. Richer, Ed.
Internet-Draft The MITRE Corporation
Intended status: Standards Track J. Bradley
Expires: August 25, 2013 Ping Identity
M. Jones
Microsoft
M. Machulak
Newcastle University
February 21, 2013
OAuth Dynamic Client Registration Protocol
draft-ietf-oauth-dyn-reg-07
Abstract
This specification defines an endpoint and protocol for dynamic
registration of OAuth Clients at an Authorization Server.
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/.
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 August 25, 2013.
Copyright Notice
Copyright (c) 2013 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
(http://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
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Notational Conventions . . . . . . . . . . . . . . . . . . 3
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Client Metadata . . . . . . . . . . . . . . . . . . . . . . . 4
3. Client Registration Endpoint . . . . . . . . . . . . . . . . . 7
3.1. Client Registration Request . . . . . . . . . . . . . . . 8
3.2. Client Registration Response . . . . . . . . . . . . . . . 9
4. Client Configuration Endpoint . . . . . . . . . . . . . . . . 9
4.1. Forming the Client Configuration Endpoint URL . . . . . . 9
4.2. Client Read Request . . . . . . . . . . . . . . . . . . . 10
4.3. Client Update Request . . . . . . . . . . . . . . . . . . 10
4.4. Client Delete Request . . . . . . . . . . . . . . . . . . 12
5. Responses . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1. Client Information Response . . . . . . . . . . . . . . . 13
5.2. Client Registration Error Response . . . . . . . . . . . . 15
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16
7. Security Considerations . . . . . . . . . . . . . . . . . . . 16
8. Normative References . . . . . . . . . . . . . . . . . . . . . 17
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 18
Appendix B. Document History . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20
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1. Introduction
In some use-case scenarios, it is desirable or necessary to allow
OAuth clients to obtain authorization from an OAuth authorization
server without requiring the two parties to interact beforehand.
Nevertheless, in order for the authorization server to accurately and
securely represent to end-users which client is seeking authorization
to access the end-user's resources, a method for automatic and unique
registration of clients is needed. The OAuth2 authorization
framework does not define how the relationship between the Client and
the Authorization Server is initialized, or how a given client is
assigned a unique Client Identifier. Historically, this has happened
out-of-band from the OAuth protocol. This draft provides a mechanism
for a client to register itself with the Authorization Server, which
can be used to dynamically provision a Client Identifier, and
optionally a Client Secret.
As part of the registration process, this specification also defines
a mechanism for the client to present the Authorization Server with a
set of metadata, such as a display name and icon to be presented to
the user during the authorization step. This draft also provides a
mechanism for the Client to read and update this information after
the initial registration action.
1.1. Notational Conventions
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.
1.2. Terminology
This specification uses the terms "Access Token", "Refresh Token",
"Authorization Code", "Authorization Grant", "Authorization Server",
"Authorization Endpoint", "Client", "Client Identifier", "Client
Secret", "Protected Resource", "Resource Owner", "Resource Server",
and "Token Endpoint" defined by OAuth 2.0 [RFC6749].
This specification defines the following additional terms:
o Client Registration Endpoint: The OAuth 2.0 Endpoint through which
a Client can request new registration. The means of the Client
obtaining the URL for this endpoint are out of scope for this
specification.
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o Client Configuration Endpoint: The OAuth 2.0 Endpoint through
which a specific Client can manage its registration information,
provided by the Authorization Server to the Client. This URL for
this endpoint is communicated to the client by the Authorization
Server in the Client Information Response.
o Registration Access Token: An OAuth 2.0 Bearer Token issued by the
Authorization Server through the Client Registration Endpoint
which is used by the Client to authenticate itself during read,
update, and delete operations. This token is associated with a
particular Client.
2. Client Metadata
Clients generally have an array of metadata associated with their
unique Client Identifier at the Authorization Server. These can
range from human-facing display strings, such as a client name, to
items that impact the security of the protocol, such as the list of
valid redirect URIs.
Extensions and profiles of this specification MAY expand this list,
but MUST at least accept all parameters on this list. The
Authorization Server MUST ignore any additional parameters sent by
the Client that it does not understand.
[[ Editor's note: normative language in the table below is meant to
apply to the *client* when sending the request. The paragraph above
is meant to say that the server must at least accept all parameters
and not fail with an error at an unknown parameter, especially if
it's in the list below. Also, extensions need to explicitly call out
if they're not going to do something with one of these basic
parameters instead of just ignoring their existence. This is meant
to be the *minimum set* of parameters for interoperability. ]]
redirect_uris
RECOMMENDED. Array of redirect URIs for use in the Authorization
Code and Implicit grant types. An Authorization Server SHOULD
require registration of valid redirect URIs for all clients that
use these grant types in order to protect against token and
credential theft attacks.
client_name
RECOMMENDED. Human-readable name of the Client to be presented to
the user. If omitted, the Authorization Server MAY display to the
user the raw "client_id" value instead.
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client_uri
RECOMMENDED. URL of the homepage of the Client. If present, the
server SHOULD display this URL to the end user in a clickable
fashion.
logo_uri
OPTIONAL. URL that references a logo for the Client. If present,
the server SHOULD display this image to the end user during
approval.
contacts
OPTIONAL. Array of email addresses for people responsible for
this Client. The Authorization Server MAY make these addresses
available to end users for support requests for the Client. An
Authorization Server MAY use these email addresses as identifiers
for an administrative page for this client.
tos_uri
OPTIONAL. URL that points to a human-readable Terms of Service
for the Client. The Authorization Server SHOULD display this URL
to the End-User if it is given.
token_endpoint_auth_method
OPTIONAL. The requested authentication type for the Token
Endpoint. Valid values are:
* "none": this is a public client as defined in OAuth 2.0 and
does not have a client secret
* "client_secret_post": the client uses the HTTP POST parameters
defined in OAuth2.0 section 2.3.1
* "client_secret_basic": the client uses HTTP Basic defined in
OAuth 2.0 section 2.3.1
* "client_secret_jwt": the client uses the JWT Assertion profile
with a symmetric secret issued by the server
* "private_key_jwt": the client uses the JWT Assertion profile
with its own private key
Other authentication methods may be defined by extension. If
unspecified or omitted, the default is "client_secret_basic",
denoting HTTP Basic Authentication Scheme as specified in Section
2.3.1 of OAuth 2.0.
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scope
OPTIONAL. Space separated list of scope values (as described in
OAuth 2.0 Section 3.3 [RFC6749]) that the client is declaring that
it may use when requesting access tokens. If omitted, an
Authorization Server MAY register a Client with a default set of
scopes.
grant_type
OPTIONAL. Array of grant types that a client may use. These
grant types are defined as follows:
* "authorization_code": The Authorization Code Grant described in
OAuth2 Section 4.1.
* "implicit": The Implicit Grant described in OAuth2 Section 4.2.
* "password": The Resource Owner Password Credentials Grant
described in OAuth2 Section 4.3
* "client_credentials": The Client Credentials Grant described in
OAuth2 Section 4.4
* "refresh_token": The Refresh Token Grant described in OAuth2
Section 6.
Authorization Servers MAY allow for other values as defined in
grant type extensions to OAuth2. The extension process is
described in OAuth2 Section 2.5, and the value of this parameter
MUST be the same as the value of the "grant_type" parameter
defined in the extension.
policy_uri
OPTIONAL. A URL location that the Client provides to the End-User
to read about the how the profile data will be used. The
Authorization Server SHOULD display this URL to the End-User if it
is given.
jwk_uri
OPTIONAL. URL for the Client's JSON Web Key [JWK] document that
is used for signing requests, such as requests to the Token
Endpoint using the "private_key_jwt" assertion client credential.
If the Client registers both "x509_uri" and "jwk_uri", the keys
contained in both formats MUST be the same.
jwk_encryption_uri
OPTIONAL. URL for the Client's JSON Web Key [JWK] that the server
can use to encrypt responses to the Client. If the Client
registers both "jwk_encryption_uri" and "x509_encryption_uri", the
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keys contained in both formats MUST be the same.
x509_uri
OPTIONAL. URL for the Client's PEM encoded X.509 Certificate or
Certificate chain that is used for signing requests, such as
requests to the Token Endpoint using the "private_key_jwt"
assertion client credential. If the Client registers both
"x509_uri" and "jwk_uri", the keys contained in both formats MUST
be the same.
x509_encryption_uri
OPTIONAL. URL for the Client's PEM encoded X.509 Certificate or
Certificate chain that the server can use to encrypt responses to
the Client. If the Client registers both "jwk_encryption_uri" and
"x509_encryption_uri", the keys contained in both formats MUST be
the same.
3. Client Registration Endpoint
The Client Registration Endpoint is an OAuth 2.0 Endpoint defined in
this document that is designed to allow a Client to register itself
with the Authorization Server. The Client Registration Endpoint MUST
accept HTTP POST messages with request parameters encoded in the
entity body using the "application/json" format. The Client
Registration Endpoint MUST be protected by a transport-layer security
mechanism, and the server MUST support TLS 1.2 RFC 5246 [RFC5246]
and/or TLS 1.0 [RFC2246] 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].
The Client Registration Endpoint MAY accept an initial authorization
credential in the form of an OAuth 2.0 [RFC6749] access token in
order to limit registration to only previously authorized parties.
The method by which this access token is obtained by the registrant
is generally out-of-band and is out of scope of this specification.
In order to support open registration and facilitate wider
interoperability, the Client Registration Endpoint SHOULD allow
initial registration requests with no authentication. These requests
MAY be rate-limited or otherwise limited to prevent a denial-of-
service attack on the Client Registration Endpoint.
In order to facilitate registered clients updating their information,
the Client Registration Endpoint issues a Request Access Token for
clients to securely identify themselves in future connections to the
Client Configuration Endpoint (Section 4). As such, the Client
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Configuration Endpoint MUST accept requests with OAuth 2.0 Bearer
Tokens [RFC6750] for these operations, whether or not the initial
registration call requires authentication of some form.
The Client Registration Endpoint MUST ignore all parameters it does
not understand.
3.1. Client Registration Request
This operation registers a new Client to the Authorization Server.
The Authorization Server assigns this client a unique Client
Identifier, optionally assigns a Client Secret, and associates the
metadata given in the request with the issued Client Identifier. The
request includes any parameters described in Client Metadata
(Section 2) that the client wishes to specify for itself during the
registration. The Authorization Server MAY provision default values
for any items omitted in the Client Metadata.
The Client sends an HTTP POST to the Client Registration Endpoint
with a content type of "application/json". The HTTP Entity Payload
is a JSON [RFC4627] document consisting of a JSON object and all
parameters as top- level members of that JSON object.
For example, a client could send the following registration request
to the Client Registration Endpoint:
Following is a non-normative example request (with line wraps for
display purposes only):
POST /register HTTP/1.1
Content-Type: application/json
Accept: application/json
Host: server.example.com
{
"redirect_uris":["https://client.example.org/callback",
"https://client.example.org/callback2"]
"client_name":"My Example Client",
"token_endpoint_auth_method":"client_secret_basic",
"scope":"read write dolphin",
"logo_uri":"https://client.example.org/logo.png",
"jwk_uri":"https://client.example.org/my_rsa_public_key.jwk"
}
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3.2. Client Registration Response
Upon successful registration, the Authorization Server generates a
new Client Identifier for the client. This Client Identifier MUST be
unique at the server and MUST NOT be in use by any other client. The
server responds with an HTTP 201 Created code and a body of type
"application/json" with content described in Client Information
Response (Section 5.1).
Upon an unsuccessful registration, the Authorization Server responds
with an error as described in Client Registration Error
(Section 5.2).
4. Client Configuration Endpoint
The Client Configuration Endpoint is an OAuth 2.0 protected endpoint
that is provisioned by the server for a specific client to be able to
view and update its registered information. The Client MUST include
its Registration Access Token in all calls to this endpoint as an
OAuth 2.0 Bearer Token [RFC6750].
Operations on this endpoint are switched through the use of different
HTTP methods [RFC2616].
4.1. Forming the Client Configuration Endpoint URL
The Authorization Server MUST provide the client with the fully
qualified URL in the "registration_client_uri" element of the Client
Information Response (Section 5.1). 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 ID "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 follows the
URL as given.
These common patterns can help the Server to more easily determine
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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.
4.2. Client Read Request
In order 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
Client Information Response (Section 5.1).
If the client does not exist on this server, the server MUST return
an HTTP 403 Forbidden.
If the Client does not have permission to read its record, the server
MUST return an HTTP 403 Forbidden.
4.3. Client Update Request
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 [RFC4627] document consisting of a JSON object and all
parameters as top- level members of that JSON object.
This request MUST include all fields described in Client Metadata
(Section 2) as returned to the Client from a previous register, read,
or update operation. The Client MUST NOT include the
"registration_access_token", "registration_client_uri", "expires_at",
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or "issued_at" fields described in Client Information Response
(Section 5.1).
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.
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 its client_secret in the request, then it 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
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:
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"],
"scope": "read write dolphin",
"grant_type": ["authorization_code", "refresh_token"]
"token_endpoint_auth_method": "client_secret_basic",
"jwk_uri": "https://client.example.org/my_rsa_public_key.jwk"
"client_name":"My New Example",
"logo_uri":"https://client.example.org/newlogo.png"
}
Upon successful update, the Authorization Server responds with an
HTTP 200 OK Message with content type "application/json" and a
payload as described in Client Information Response (Section 5.1).
The Authorization Server MAY include a new Client Secret and/or
Registration Access Token in its response. If so, the Client MUST
immediately discard its previous Client Secret and/or Registration
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Access Token.
If the Client does not exist on this server, the server MUST return
an HTTP 403 Forbidden.
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 Client Registration
Error Response (Section 5.2).
4.4. Client Delete Request
[[ Editor's note: The utility and nature of this function are still
under active discussion. This is a proposed set of functionality
that a server MAY choose to implement, else give a 405 response to
any client that tries, if it can't support it. ]]
In order 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.
Following is a non-normative example request (with line wraps for
display purposes only):
DELETE /register/s6BhdRkqt3 HTTP/1.1
Accept: application/json
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. The
Authorization Server SHOULD immediately invalidate all existing
authorization grants and currently-active tokens associated with this
Client.
If a Client has been successfully deprovisioned, the Authorization
Server responds with an HTTP 204 No Content message.
If there is no such client, the server responds with an HTTP 403
Forbidden.
If the client is not allowed to delete itself, the server responds
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with HTTP 403 Forbidden.
If the server does not support the delete method, it responds with an
HTTP 405 Not Supported.
Following is a non-normative example response:
HTTP/1.1 204 No Content
Cache-Control: no-store
Pragma: no-cache
5. Responses
In response to certain requests from the Client to either the Client
Registration Endpoint or the Client Configuration Endpoint as
described in this specification, the Authorization Server sends the
following response bodies.
5.1. Client Information Response
The response contains the Client Identifier as well as the Client
Secret, if the Client is a confidential Client. The response also
contains the fully qualified URL to the Client Configuration Endpoint
for this specific client that the client may use to obtain and update
information about itself. The response also contains a Registration
Access Token that is to be used by the client to perform subsequent
operations at the Client Configuration Endpoint.
client_id
REQUIRED. The unique Client identifier, MUST NOT be currently
valid for any other registered Client.
client_secret
OPTIONAL. The Client secret. If issued, this MUST be unique for
each "client_id". This value is used by confidential clients to
authenticate to the Token Endpoint as described in OAuth 2.0
Section 2.3.1.
expires_at
REQUIRED if "client_secret" is issued. The number of seconds from
1970-01-01T0:0:0Z as measured in UTC that the "client_secret" will
expire or "0" if it does not expire. See RFC 3339 [RFC3339] for
details regarding date/times in general and UTC in particular.
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issued_at
OPTIONAL. Specifies the timestamp when the Client Identifier was
issued. The timestamp value MUST be a positive integer. The
value is expressed in the number of seconds since January 1, 1970
00:00:00 GMT.
registration_access_token
REQUIRED. The Access token to be used by the client to perform
actions on the Client Configuration Endpoint.
registration_client_uri
REQUIRED. The fully qualified URL of the Client Configuration
Endpoint for this client. The Client MUST use this URL as given
when communicating with the Client Configuration Endpoint.
Additionally, the Authorization Server MUST return all registered
metadata (Section 2) 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 [RFC4627].
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",
"expires_at":2893276800
"redirect_uris":["https://client.example.org/callback",
"https://client.example.org/callback2"]
"scope": "read write dolphin",
"grant_type": ["authorization_code", "refresh_token"]
"token_endpoint_auth_method": "client_secret_basic",
"logo_uri": "https://client.example.org/logo.png",
"jwk_uri": "https://client.example.org/my_rsa_public_key.jwk"
}
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5.2. Client Registration Error Response
When an OAuth error condition occurs, such as the client presenting
an invalid Registration Access Token, the Authorization Server
returns an Error Response as defined in Section 5.2 of the OAuth 2.0
specification.
When a registration error condition occurs, the Authorization Server
returns an HTTP 400 status code with content type "application/json"
consisting of a JSON object [RFC4627] describing the error in the
response body.
The JSON object contains two members:
error
The error code, a single ASCII string.
error_description
A human-readable text description of the error for debugging.
This specification defines the following error codes:
invalid_redirect_uri
The value of one or more "redirect_uris" is invalid.
invalid_client_metadata
The value of one of the client metadata (Section 2) fields is
invalid and the server has rejected this request. Note that an
Authorization server MAY choose to substitute a valid value for
any requested parameter of a client's metadata.
invalid_client_id
Value of "client_id" is invalid.
Following is a non-normative example of an error response (with line
wraps for display purposes only):
HTTP/1.1 400 Bad Request
Content-Type: application/json
Cache-Control: no-store
Pragma: no-cache
{
"error":"invalid_redirect_uri",
"error_description":"The redirect URI of http://sketchy.example.com
is not allowed for this server."
}
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6. IANA Considerations
This document makes no requests of IANA.
7. Security Considerations
[[ Editor's note: Following are some security considerations taken
from the UMA and OpenID Connect source drafts. These need to be
massaged into a properly generic set of considerations. ]]
Since requests to the Client Registration Endpoint result in the
transmission of clear-text credentials (in the HTTP request and
response), the server MUST require the use of a transport-layer
security mechanism when sending requests to the Registration
Endpoint. The server MUST support TLS 1.2 RFC 5246 [RFC5246] and/or
TLS 1.0 [RFC2246] 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].
As this endpoint is an OAuth2 Protected Resource, requests to the
Registration Endpoint SHOULD have some rate limiting on failures to
prevent the Registration Access Token from being disclosed though
repeated access attempts.
The authorization server MUST treat all client metadata as self-
asserted. A rogue Client might use the name and logo for the
legitimate Client, which it is trying to impersonate. An
Authorization Server needs to take steps to mitigate this phishing
risk, since the logo could confuse users into thinking they're
logging in to the legitimate Client. For instance, an Authorization
Server could warn if the domain/site of the logo doesn't match the
domain/site of redirect URIs. An Authorization Server can also
present warning messages to end users about untrusted Clients in all
cases, especially if such clients have been dynamically registered
and have not been trusted by any users at the Authorization Server
before.
In a situation where the Authorization Server is supporting open
Client registration, it must be extremely careful with any URL
provided by the Client that will be displayed to the user (e.g.
"logo_uri" and "policy_uri"). A rogue Client could specify a
registration request with a reference to a drive-by download in the
"policy_uri". The Authorization Server should check to see if the
"logo_uri" and "policy_uri" have the same host as the hosts defined
in the array of "redirect_uris".
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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 Client could be left in a situation
where it has no means of updating itself and must register itself
anew. As the Registration Access Tokens are 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 Client as described in OAuth 2.0 Bearer
[RFC6750].
If a Client is deprovisioned from a server, any outstanding
Registration Access Tokens 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.
8. Normative References
[JWK] Jones, M., "JSON Web Key (JWK)", May 2012.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2246] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0",
RFC 2246, January 1999.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[RFC3339] Klyne, G., Ed. and C. Newman, "Date and Time on the
Internet: Timestamps", RFC 3339, July 2002.
[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.
[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and
Verification of Domain-Based Application Service Identity
within Internet Public Key Infrastructure Using X.509
(PKIX) Certificates in the Context of Transport Layer
Security (TLS)", RFC 6125, March 2011.
[RFC6749] Hardt, D., "The OAuth 2.0 Authorization Framework",
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RFC 6749, October 2012.
[RFC6750] Jones, M. and D. Hardt, "The OAuth 2.0 Authorization
Framework: Bearer Token Usage", RFC 6750, October 2012.
Appendix A. Acknowledgments
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, Tim Bray,
Domenico Catalano, George Fletcher, Torsten Lodderstedt, Eve Maler,
Thomas Hardjono, Nat Sakimura, and Christian Scholz.
Appendix B. Document History
[[ to be removed by the RFC editor before publication as an RFC ]]
-07
o Changed registration_access_url to registration_client_uri
o Fixed missing text in 5.1
o Added Pragma: no-cache to examples
o Changed "no such client" error to 403
o Renamed Client Registration Access Endpoint to Client
Configuration Endpoint
o Changed all the parameter names containing "_url" to instead use
"_uri"
o Updated example text for forming Client Configuration Endpoint URL
-06
o Removed secret_rotation as a client-initiated action, including
removing client secret rotation endpoint and parameters.
o Changed _links structure to single value registration_access_url.
o Collapsed create/update/read responses into client info response.
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o Changed return code of create action to 201.
o Added section to describe suggested generation and composition of
Client Registration Access URL.
o Added clarifying text to PUT and POST requests to specify JSON in
the body.
o Added Editor's Note to DELETE operation about its inclusion.
o Added Editor's Note to registration_access_url about alternate
syntax proposals.
-05
o changed redirect_uri and contact to lists instead of space
delimited strings
o removed operation parameter
o added _links structure
o made client update management more RESTful
o split endpoint into three parts
o changed input to JSON from form-encoded
o added READ and DELETE operations
o removed Requirements section
o changed token_endpoint_auth_type back to
token_endpoint_auth_method to match OIDC who changed to match us
-04
o removed default_acr, too undefined in the general OAuth2 case
o removed default_max_auth_age, since there's no mechanism for
supplying a non-default max_auth_age in OAuth2
o clarified signing and encryption URLs
o changed token_endpoint_auth_method to token_endpoint_auth_type to
match OIDC
-03
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o added scope and grant_type claims
o fixed various typos and changed wording for better clarity
o endpoint now returns the full set of client information
o operations on client_update allow for three actions on metadata:
leave existing value, clear existing value, replace existing value
with new value
-02
o Reorganized contributors and references
o Moved OAuth references to RFC
o Reorganized model/protocol sections for clarity
o Changed terminology to "client register" instead of "client
associate"
o Specified that client_id must match across all subsequent requests
o Fixed RFC2XML formatting, especially on lists
-01
o Merged UMA and OpenID Connect registrations into a single document
o Changed to form-paramter inputs to endpoint
o Removed pull-based registration
-00
o Imported original UMA draft specification
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Authors' Addresses
Justin Richer (editor)
The MITRE Corporation
Phone:
Fax:
Email: jricher@mitre.org
URI:
John Bradley
Ping Identity
Email: ve7jtb@ve7jtb.com
Michael B. Jones
Microsoft
Email: mbj@microsoft.com
Maciej Machulak
Newcastle University
Email: m.p.machulak@ncl.ac.uk
URI: http://ncl.ac.uk/
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