OAuth Working Group M. Jones
Internet-Draft Microsoft
Intended status: Standards Track N. Sakimura
Expires: January 9, 2017 NRI
J. Bradley
Ping Identity
July 8, 2016
OAuth 2.0 Authorization Server Discovery Metadata
draft-ietf-oauth-discovery-03
Abstract
This specification defines a discovery metadata format that an OAuth
2.0 client can use to obtain the information needed to interact with
an OAuth 2.0 authorization server, including its endpoint locations
and authorization server capabilities.
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
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Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 9, 2017.
Copyright Notice
Copyright (c) 2016 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
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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 . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Notation and Conventions . . . . . . . . . . 3
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Authorization Server Metadata . . . . . . . . . . . . . . . . 3
3. Obtaining Authorization Server Discovery Metadata . . . . . . 7
3.1. Authorization Server Discovery Metadata Request . . . . . 8
3.2. Authorization Server Discovery Metadata Response . . . . 8
3.3. Authorization Server Discovery Metadata Validation . . . 9
4. String Operations . . . . . . . . . . . . . . . . . . . . . . 10
5. Compatibility Notes . . . . . . . . . . . . . . . . . . . . . 10
6. Security Considerations . . . . . . . . . . . . . . . . . . . 10
6.1. TLS Requirements . . . . . . . . . . . . . . . . . . . . 10
6.2. Impersonation Attacks . . . . . . . . . . . . . . . . . . 11
6.3. Publishing Metadata in a Standard Format . . . . . . . . 11
6.4. Protected Resources . . . . . . . . . . . . . . . . . . . 11
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
7.1. OAuth Authorization Server Discovery Metadata Registry . 13
7.1.1. Registration Template . . . . . . . . . . . . . . . . 13
7.1.2. Initial Registry Contents . . . . . . . . . . . . . . 13
7.2. Updated Registration Instructions . . . . . . . . . . . . 17
7.3. Well-Known URI Registry . . . . . . . . . . . . . . . . . 17
7.3.1. Registry Contents . . . . . . . . . . . . . . . . . . 17
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 17
8.1. Normative References . . . . . . . . . . . . . . . . . . 17
8.2. Informative References . . . . . . . . . . . . . . . . . 20
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 21
Appendix B. Document History . . . . . . . . . . . . . . . . . . 21
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22
1. Introduction
This specification generalizes the discovery metadata format defined
by "OpenID Connect Discovery 1.0" [OpenID.Discovery] in a way that is
compatible with OpenID Connect Discovery, while being applicable to a
wider set of OAuth 2.0 use cases. This is intentionally parallel to
the way that the "OAuth 2.0 Dynamic Client Registration Protocol"
[RFC7591] specification generalized the dynamic client registration
mechanisms defined by "OpenID Connect Dynamic Client Registration
1.0" [OpenID.Registration] in a way that was compatible with it.
The discovery metadata for an authorization server is retrieved from
a well-known location as a JSON [RFC7159] document, which declares
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its endpoint locations and authorization server capabilities. This
process is described in Section 3.
The means by which the client obtains the location of the
authorization server discovery metadata document is out of scope. In
some cases, the location may be manually configured into the client.
In other cases, it may be dynamically discovered, for instance,
through the use of WebFinger [RFC7033], as described in Section 2 of
"OpenID Connect Discovery 1.0" [OpenID.Discovery].
1.1. Requirements Notation and Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in RFC
2119 [RFC2119].
All uses of JSON Web Signature (JWS) [JWS] and JSON Web Encryption
(JWE) [JWE] data structures in this specification utilize the JWS
Compact Serialization or the JWE Compact Serialization; the JWS JSON
Serialization and the JWE JSON Serialization are not used.
1.2. Terminology
This specification uses the terms "Access Token", "Authorization
Code", "Authorization Endpoint", "Authorization Grant",
"Authorization Server", "Client", "Client Authentication", "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], the terms "Claim Name", "Claim Value", and "JSON Web Token
(JWT)" defined by JSON Web Token (JWT) [JWT], and the term "Response
Mode" defined by OAuth 2.0 Multiple Response Type Encoding Practices
[OAuth.Responses].
2. Authorization Server Metadata
Authorization servers can have metadata describing their
configuration. The following authorization server metadata values
are used by this specification and are registered in the IANA "OAuth
Authorization Server Discovery Metadata" registry established in
Section 7.1:
issuer
REQUIRED. The authorization server's issuer identifier, which is
a URL that uses the "https" scheme and has no query or fragment
components. This is the location where ".well-known" RFC 5785
[RFC5785] resources containing information about the authorization
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server are published. Using these well-known resources is
described in Section 3. The issuer identifier is used to prevent
authorization server mix-up attacks, as described in "OAuth 2.0
Mix-Up Mitigation" [I-D.ietf-oauth-mix-up-mitigation].
authorization_endpoint
REQUIRED. URL of the authorization server's authorization
endpoint [RFC6749].
token_endpoint
URL of the authorization server's token endpoint [RFC6749]. This
is REQUIRED unless only the implicit grant type is used.
jwks_uri
OPTIONAL. URL of the authorization server's JWK Set [JWK]
document. This contains the signing key(s) the client uses to
validate signatures from the authorization server. The JWK Set
MAY also contain the server's encryption key(s), which are used by
clients to encrypt requests to the server. When both signing and
encryption keys are made available, a "use" (public key use)
parameter value is REQUIRED for all keys in the referenced JWK Set
to indicate each key's intended usage. Although some algorithms
allow the same key to be used for both signatures and encryption,
doing so is NOT RECOMMENDED, as it is less secure. The JWK "x5c"
parameter MAY be used to provide X.509 representations of keys
provided. When used, the bare key values MUST still be present
and MUST match those in the certificate.
registration_endpoint
OPTIONAL. URL of the authorization server's OAuth 2.0 Dynamic
Client Registration endpoint [RFC7591].
scopes_supported
RECOMMENDED. JSON array containing a list of the OAuth 2.0
[RFC6749] "scope" values that this authorization server supports.
Servers MAY choose not to advertise some supported scope values
even when this parameter is used.
response_types_supported
REQUIRED. JSON array containing a list of the OAuth 2.0
"response_type" values that this authorization server supports.
The array values used are the same as those used with the
"response_types" parameter defined by "OAuth 2.0 Dynamic Client
Registration Protocol" [RFC7591].
response_modes_supported
OPTIONAL. JSON array containing a list of the OAuth 2.0
"response_mode" values that this authorization server supports, as
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specified in OAuth 2.0 Multiple Response Type Encoding Practices
[OAuth.Responses]. If omitted, the default is "["query",
"fragment"]". The response mode value "form_post" is also defined
in OAuth 2.0 Form Post Response Mode [OAuth.Post].
grant_types_supported
OPTIONAL. JSON array containing a list of the OAuth 2.0 grant
type values that this authorization server supports. The array
values used are the same as those used with the "grant_types"
parameter defined by "OAuth 2.0 Dynamic Client Registration
Protocol" [RFC7591]. If omitted, the default value is
"["authorization_code", "implicit"]".
token_endpoint_auth_methods_supported
OPTIONAL. JSON array containing a list of client authentication
methods supported by this token endpoint. Client authentication
method values are used in the "token_endpoint_auth_method"
parameter defined in Section 2 of [RFC7591]. If omitted, the
default is "client_secret_basic" -- the HTTP Basic Authentication
Scheme specified in Section 2.3.1 of OAuth 2.0 [RFC6749].
token_endpoint_auth_signing_alg_values_supported
OPTIONAL. JSON array containing a list of the JWS signing
algorithms ("alg" values) supported by the token endpoint for the
signature on the JWT [JWT] used to authenticate the client at the
token endpoint for the "private_key_jwt" and "client_secret_jwt"
authentication methods. Servers SHOULD support "RS256". The
value "none" MUST NOT be used.
service_documentation
OPTIONAL. URL of a page containing human-readable information
that developers might want or need to know when using the
authorization server. In particular, if the authorization server
does not support Dynamic Client Registration, then information on
how to register clients needs to be provided in this
documentation.
ui_locales_supported
OPTIONAL. Languages and scripts supported for the user interface,
represented as a JSON array of BCP47 [RFC5646] language tag
values.
op_policy_uri
OPTIONAL. URL that the authorization server provides to the
person registering the client to read about the authorization
server's requirements on how the client can use the data provided
by the authorization server. The registration process SHOULD
display this URL to the person registering the client if it is
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given. As described in Section 5, despite the identifier
"op_policy_uri", appearing to be OpenID-specific, its usage in
this specification is actually referring to a general OAuth 2.0
feature that is not specific to OpenID Connect.
op_tos_uri
OPTIONAL. URL that the authorization server provides to the
person registering the client to read about authorization server's
terms of service. The registration process SHOULD display this
URL to the person registering the client if it is given. As
described in Section 5, despite the identifier "op_tos_uri",
appearing to be OpenID-specific, its usage in this specification
is actually referring to a general OAuth 2.0 feature that is not
specific to OpenID Connect.
revocation_endpoint
OPTIONAL. URL of the authorization server's OAuth 2.0 revocation
endpoint [RFC7009].
revocation_endpoint_auth_methods_supported
OPTIONAL. JSON array containing a list of client authentication
methods supported by this revocation endpoint. The valid client
authentication method values are those registered in the IANA
"OAuth Token Endpoint Authentication Methods" registry
[IANA.OAuth.Parameters].
revocation_endpoint_auth_signing_alg_values_supported
OPTIONAL. JSON array containing a list of the JWS signing
algorithms ("alg" values) supported by the revocation endpoint for
the signature on the JWT [JWT] used to authenticate the client at
the revocation endpoint for the "private_key_jwt" and
"client_secret_jwt" authentication methods. The value "none" MUST
NOT be used.
introspection_endpoint
OPTIONAL. URL of the authorization server's OAuth 2.0
introspection endpoint [RFC7662].
introspection_endpoint_auth_methods_supported
OPTIONAL. JSON array containing a list of client authentication
methods supported by this introspection endpoint. The valid
client authentication method values are those registered in the
IANA "OAuth Token Endpoint Authentication Methods" registry
[IANA.OAuth.Parameters] or those registered in the IANA "OAuth
Access Token Types" registry [IANA.OAuth.Parameters]. (These
values are and will remain distinct, due to Section 7.2.)
introspection_endpoint_auth_signing_alg_values_supported
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OPTIONAL. JSON array containing a list of the JWS signing
algorithms ("alg" values) supported by the introspection endpoint
for the signature on the JWT [JWT] used to authenticate the client
at the introspection endpoint for the "private_key_jwt" and
"client_secret_jwt" authentication methods. The value "none" MUST
NOT be used.
code_challenge_methods_supported
OPTIONAL. JSON array containing a list of PKCE [RFC7636] code
challenge methods supported by this authorization server. Code
challenge method values are used in the "code_challenge_method"
parameter defined in Section 4.3 of [RFC7636]. The valid code
challenge method values are those registered in the IANA "PKCE
Code Challenge Methods" registry [IANA.OAuth.Parameters].
Additional authorization server metadata parameters MAY also be used.
Some are defined by other specifications, such as OpenID Connect
Discovery 1.0 [OpenID.Discovery].
3. Obtaining Authorization Server Discovery Metadata
Authorization servers supporting discovery MUST make a JSON document
containing discovery metadata as specified in Section 2 available at
a path formed by concatenating a well-known URI string such as
"/.well-known/oauth-authorization-server" to the authorization
server's issuer identifier. The syntax and semantics of ".well-
known" are defined in RFC 5785 [RFC5785]. The well-known URI path
suffix used MUST be registered in the IANA "Well-Known URIs" registry
[IANA.well-known].
Different applications utilizing OAuth authorization servers in
application-specific ways may define and register different well-
known URI path suffixes used to publish authorization server metadata
as used by those applications. For instance, if the Example
application uses an OAuth authorization server in an Example-specific
way, and there are Example-specific metadata values that it needs to
publish, then it might register and use the "example-configuration"
URI path suffix and publish the metadata document at the path formed
by concatenating "/.well-known/example-configuration" to the
authorization server's issuer identifier.
An OAuth 2.0 application using this specification MUST specify what
well-known URI string it will use for this purpose. The same
authorization server MAY choose to publish its metadata at multiple
well-known locations relative to its issuer identifier, for example,
publishing metadata at both "/.well-known/example-configuration" and
"/.well-known/oauth-authorization-server".
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Some OAuth applications will choose to use the well-known URI path
suffix "openid-configuration" and publish the metadata document at
the path formed by concatenating "/.well-known/openid-configuration"
to the authorization server's issuer identifier. As described in
Section 5, despite the identifier "/.well-known/openid-
configuration", appearing to be OpenID-specific, its usage in this
specification is actually referring to a general OAuth 2.0 feature
that is not specific to OpenID Connect.
3.1. Authorization Server Discovery Metadata Request
An authorization server discovery metadata document MUST be queried
using an HTTP "GET" request at the previously specified path.
The client would make the following request when the issuer
identifier is "https://example.com" and the well-known URI path
suffix is "oauth-authorization-server" to obtain the discovery
metadata, since the issuer identifier contains no path component:
GET /.well-known/oauth-authorization-server HTTP/1.1
Host: example.com
If the issuer identifier value contains a path component, any
terminating "/" MUST be removed before appending "/.well-known/" and
the well-known URI path suffix. The client would make the following
request when the issuer identifier is "https://example.com/issuer1"
and the well-known URI path suffix is "oauth-authorization-server" to
obtain the discovery metadata, since the issuer identifier contains a
path component:
GET /issuer1/.well-known/oauth-authorization-server HTTP/1.1
Host: example.com
Using path components enables supporting multiple issuers per host.
This is required in some multi-tenant hosting configurations. This
use of ".well-known" is for supporting multiple issuers per host;
unlike its use in RFC 5785 [RFC5785], it does not provide general
information about the host.
3.2. Authorization Server Discovery Metadata Response
The response is a set of claims about the authorization server's
configuration, including all necessary endpoints and public key
location information. A successful response MUST use the 200 OK HTTP
status code and return a JSON object using the "application/json"
content type that contains a set of claims as its members that are a
subset of the metadata values defined in Section 2. Other claims MAY
also be returned.
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Claims that return multiple values are represented as JSON arrays.
Claims with zero elements MUST be omitted from the response.
An error response uses the applicable HTTP status code value.
The following is a non-normative example response:
HTTP/1.1 200 OK
Content-Type: application/json
{
"issuer":
"https://server.example.com",
"authorization_endpoint":
"https://server.example.com/authorize",
"token_endpoint":
"https://server.example.com/token",
"token_endpoint_auth_methods_supported":
["client_secret_basic", "private_key_jwt"],
"token_endpoint_auth_signing_alg_values_supported":
["RS256", "ES256"],
"userinfo_endpoint":
"https://server.example.com/userinfo",
"jwks_uri":
"https://server.example.com/jwks.json",
"registration_endpoint":
"https://server.example.com/register",
"scopes_supported":
["openid", "profile", "email", "address",
"phone", "offline_access"],
"response_types_supported":
["code", "code token"],
"service_documentation":
"http://server.example.com/service_documentation.html",
"ui_locales_supported":
["en-US", "en-GB", "en-CA", "fr-FR", "fr-CA"]
}
3.3. Authorization Server Discovery Metadata Validation
The "issuer" value returned MUST be identical to the authorization
server's issuer identifier value that was concatenated with the well-
known URI path suffix to create the URL used to retrieve the
discovery metadata. If these values are not identical, the data
contained in the response MUST NOT be used.
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4. String Operations
Processing some OAuth 2.0 messages requires comparing values in the
messages to known values. For example, the member names in the
discovery metadata response might be compared to specific member
names such as "issuer". Comparing Unicode [UNICODE] strings,
however, has significant security implications.
Therefore, comparisons between JSON strings and other Unicode strings
MUST be performed as specified below:
1. Remove any JSON applied escaping to produce an array of Unicode
code points.
2. Unicode Normalization [USA15] MUST NOT be applied at any point to
either the JSON string or to the string it is to be compared
against.
3. Comparisons between the two strings MUST be performed as a
Unicode code point to code point equality comparison.
5. Compatibility Notes
The identifiers "/.well-known/openid-configuration", "op_policy_uri",
and "op_tos_uri" contain strings referring to the OpenID Connect
[OpenID.Core] family of specifications that were originally defined
by "OpenID Connect Discovery 1.0" [OpenID.Discovery]. Despite the
reuse of these identifiers that appear to be OpenID-specific, their
usage in this specification is actually referring to general OAuth
2.0 features that are not specific to OpenID Connect.
6. Security Considerations
6.1. TLS Requirements
Implementations MUST support TLS. Which version(s) ought to be
implemented will vary over time, and depend on the widespread
deployment and known security vulnerabilities at the time of
implementation. The authorization server MUST support TLS version
1.2 [RFC5246] and MAY support additional transport-layer security
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 [BCP195].
To protect against information disclosure and tampering,
confidentiality protection MUST be applied using TLS with a
ciphersuite that provides confidentiality and integrity protection.
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6.2. Impersonation Attacks
TLS certificate checking MUST be performed by the client, as
described in Section 6.1, when making an authorization server
discovery metadata request. Checking that the server certificate is
valid for the issuer identifier URL prevents man-in-middle and DNS-
based attacks. These attacks could cause a client to be tricked into
using an attacker's keys and endpoints, which would enable
impersonation of the legitimate authorization server. If an attacker
can accomplish this, they can access the resources that the affected
client has access to using the authorization server that they are
impersonating.
An attacker may also attempt to impersonate an authorization server
by publishing a discovery document that contains an "issuer" claim
using the issuer identifier URL of the authorization server being
impersonated, but with its own endpoints and signing keys. This
would enable it to impersonate that authorization server, if accepted
by the client. To prevent this, the client MUST ensure that the
issuer identifier URL it is using as the prefix for the discovery
metadata request exactly matches the value of the "issuer" metadata
value in the authorization server discovery metadata document
received by the client.
6.3. Publishing Metadata in a Standard Format
Publishing information about the authorization server in a standard
format makes it easier for both legitimate clients and attackers to
use the authorization server. Whether an authorization server
publishes its metadata in an ad-hoc manner or in the standard format
defined by this specification, the same defenses against attacks that
might be mounted that use this information should be applied.
6.4. Protected Resources
Secure determination of appropriate protected resource endpoints to
use with an authorization server is out of scope of this
specification. This specification assumes that the client has a
means of determining appropriate resource endpoint(s) to use with an
authorization server and that the client is using the correct
discovery metadata for each authorization server. Implementers need
to be aware that if an inappropriate resource endpoint is used by the
client, that an attacker may be able to act as a man-in-the-middle
proxy to a valid protected resource without it being detected by the
authorization server or the client.
The ways to determine the appropriate protected resources to use with
an authorization server are in general, application-dependent. For
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instance, some authorization servers are used with a fixed protected
resource or set of protected resources, the locations of which may be
well known, or which could be published as metadata values by the
authorization server. In other cases, the set of resources that can
be used with an authorization server can by dynamically changed by
administrative actions. Many other means of determining appropriate
associations between authorization servers and protected resources
are also possible.
7. IANA Considerations
The following registration procedure is used for the registry
established by this specification.
Values are registered on a Specification Required [RFC5226] basis
after a two-week review period on the oauth-ext-review@ietf.org
mailing list, on the advice of one or more Designated Experts.
However, to allow for the allocation of values prior to publication,
the Designated Experts may approve registration once they are
satisfied that such a specification will be published.
Registration requests sent to the mailing list for review should use
an appropriate subject (e.g., "Request to register OAuth
Authorization Server Discovery Metadata: example").
Within the review period, the Designated Experts will either approve
or deny the registration request, communicating this decision to the
review list and IANA. Denials should include an explanation and, if
applicable, suggestions as to how to make the request successful.
Registration requests that are undetermined for a period longer than
21 days can be brought to the IESG's attention (using the
iesg@ietf.org mailing list) for resolution.
Criteria that should be applied by the Designated Experts includes
determining whether the proposed registration duplicates existing
functionality, determining whether it is likely to be of general
applicability or whether it is useful only for a single application,
and whether the registration makes sense.
IANA must only accept registry updates from the Designated Experts
and should direct all requests for registration to the review mailing
list.
It is suggested that multiple Designated Experts be appointed who are
able to represent the perspectives of different applications using
this specification, in order to enable broadly-informed review of
registration decisions. In cases where a registration decision could
be perceived as creating a conflict of interest for a particular
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Expert, that Expert should defer to the judgment of the other
Experts.
7.1. OAuth Authorization Server Discovery Metadata Registry
This specification establishes the IANA "OAuth Authorization Server
Discovery Metadata" registry for OAuth 2.0 authorization server
metadata names. The registry records the authorization server
metadata member and a reference to the specification that defines it.
7.1.1. Registration Template
Discovery Metadata Name:
The name requested (e.g., "issuer"). This name is case-sensitive.
Names may not match other registered names in a case-insensitive
manner unless the Designated Experts state that there is a
compelling reason to allow an exception.
Discovery Metadata Description:
Brief description of the discovery metadata (e.g., "Issuer
identifier URL").
Change Controller:
For Standards Track RFCs, list the "IESG". For others, give the
name of the responsible party. Other details (e.g., postal
address, email address, home page URI) may also be included.
Specification Document(s):
Reference to the document or documents that specify the parameter,
preferably including URIs that can be used to retrieve copies of
the documents. An indication of the relevant sections may also be
included but is not required.
7.1.2. Initial Registry Contents
o Discovery Metadata Name: "issuer"
o Discovery Metadata Description: Authorization server's issuer
identifier URL
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
o Discovery Metadata Name: "authorization_endpoint"
o Discovery Metadata Description: URL of the authorization server's
authorization endpoint
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
o Discovery Metadata Name: "token_endpoint"
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o Discovery Metadata Description: URL of the authorization server's
token endpoint
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
o Discovery Metadata Name: "jwks_uri"
o Discovery Metadata Description: URL of the authorization server's
JWK Set document
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
o Discovery Metadata Name: "registration_endpoint"
o Discovery Metadata Description: URL of the authorization server's
OAuth 2.0 Dynamic Client Registration Endpoint
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
o Discovery Metadata Name: "scopes_supported"
o Discovery Metadata Description: JSON array containing a list of
the OAuth 2.0 "scope" values that this authorization server
supports
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
o Discovery Metadata Name: "response_types_supported"
o Discovery Metadata Description: JSON array containing a list of
the OAuth 2.0 "response_type" values that this authorization
server supports
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
o Discovery Metadata Name: "response_modes_supported"
o Discovery Metadata Description: JSON array containing a list of
the OAuth 2.0 "response_mode" values that this authorization
server supports
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
o Discovery Metadata Name: "grant_types_supported"
o Discovery Metadata Description: JSON array containing a list of
the OAuth 2.0 grant type values that this authorization server
supports
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
o Discovery Metadata Name: "token_endpoint_auth_methods_supported"
o Discovery Metadata Description: JSON array containing a list of
client authentication methods supported by this token endpoint
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o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
o Discovery Metadata Name:
"token_endpoint_auth_signing_alg_values_supported"
o Discovery Metadata Description: JSON array containing a list of
the JWS signing algorithms supported by the token endpoint for the
signature on the JWT used to authenticate the client at the token
endpoint
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
o Discovery Metadata Name: "service_documentation"
o Discovery Metadata Description: URL of a page containing human-
readable information that developers might want or need to know
when using the authorization server
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
o Discovery Metadata Name: "ui_locales_supported"
o Discovery Metadata Description: Languages and scripts supported
for the user interface, represented as a JSON array of BCP47
language tag values
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
o Discovery Metadata Name: "op_policy_uri"
o Discovery Metadata Description: URL that the authorization server
provides to the person registering the client to read about the
authorization server's requirements on how the client can use the
data provided by the authorization server
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
o Discovery Metadata Name: "op_tos_uri"
o Discovery Metadata Description: URL that the authorization server
provides to the person registering the client to read about
authorization server's terms of service
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
o Discovery Metadata Name: "revocation_endpoint"
o Discovery Metadata Description: URL of the authorization server's
OAuth 2.0 revocation endpoint
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
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o Discovery Metadata Name:
"revocation_endpoint_auth_methods_supported"
o Discovery Metadata Description: JSON array containing a list of
client authentication methods supported by this revocation
endpoint
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
o Discovery Metadata Name:
"revocation_endpoint_auth_signing_alg_values_supported"
o Discovery Metadata Description: JSON array containing a list of
the JWS signing algorithms supported by the revocation endpoint
for the signature on the JWT used to authenticate the client at
the revocation endpoint
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
o Discovery Metadata Name: "introspection_endpoint"
o Discovery Metadata Description: URL of the authorization server's
OAuth 2.0 introspection endpoint
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
o Discovery Metadata Name:
"introspection_endpoint_auth_methods_supported"
o Discovery Metadata Description: JSON array containing a list of
client authentication methods supported by this introspection
endpoint
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
o Discovery Metadata Name:
"introspection_endpoint_auth_signing_alg_values_supported"
o Discovery Metadata Description: JSON array containing a list of
the JWS signing algorithms supported by the introspection endpoint
for the signature on the JWT used to authenticate the client at
the introspection endpoint
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
o Discovery Metadata Name: "code_challenge_methods_supported"
o Discovery Metadata Description: PKCE code challenge methods
supported by this authorization server
o Change Controller: IESG
o Specification Document(s): Section 2 of [[ this specification ]]
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7.2. Updated Registration Instructions
This specification adds to the instructions for the Designated
Experts of the following IANA registries, both of which are in the
"OAuth Parameters" registry [IANA.OAuth.Parameters]:
o OAuth Access Token Types
o OAuth Token Endpoint Authentication Methods
IANA has added a link to this specification in the Reference sections
of these registries. [[ RFC Editor: The above sentence is written in
the past tense as it would appear in the final specification, even
though these links won't actually be created until after the IESG has
requested publication of the specification. Please delete this note
after the links are in place. ]]
For these registries, the designated experts must reject registration
requests in one registry for values already occurring in the other
registry. This is necessary because the
"introspection_endpoint_auth_methods_supported" parameter allows for
the use of values from either registry. That way, because the values
in the two registries will continue to be mutually exclusive, no
ambiguities will arise.
7.3. Well-Known URI Registry
This specification registers the well-known URI defined in Section 3
in the IANA "Well-Known URIs" registry [IANA.well-known] established
by RFC 5785 [RFC5785].
7.3.1. Registry Contents
o URI suffix: "oauth-authorization-server"
o Change controller: IESG
o Specification document: Section 3 of [[ this specification ]]
o Related information: (none)
8. References
8.1. Normative References
[BCP195] Sheffer, Y., Holz, R., and P. Saint-Andre,
"Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security
(DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May
2015, <http://www.rfc-editor.org/info/bcp195>.
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[IANA.OAuth.Parameters]
IANA, "OAuth Parameters",
<http://www.iana.org/assignments/oauth-parameters>.
[JWA] Jones, M., "JSON Web Algorithms (JWA)", RFC 7518,
DOI 10.17487/RFC7518, May 2015,
<http://tools.ietf.org/html/rfc7518>.
[JWE] Jones, M. and J. Hildebrand, "JSON Web Encryption (JWE)",
RFC 7516, DOI 10.17487/RFC7516, May 2015,
<http://tools.ietf.org/html/rfc7516>.
[JWK] Jones, M., "JSON Web Key (JWK)", RFC 7517,
DOI 10.17487/RFC7517, May 2015,
<http://tools.ietf.org/html/rfc7517>.
[JWS] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
2015, <http://tools.ietf.org/html/rfc7515>.
[JWT] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
(JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,
<http://tools.ietf.org/html/rfc7519>.
[OAuth.Post]
Jones, M. and B. Campbell, "OAuth 2.0 Form Post Response
Mode", April 2015, <http://openid.net/specs/
oauth-v2-form-post-response-mode-1_0.html>.
[OAuth.Responses]
de Medeiros, B., Ed., Scurtescu, M., Tarjan, P., and M.
Jones, "OAuth 2.0 Multiple Response Type Encoding
Practices", February 2014, <http://openid.net/specs/
oauth-v2-multiple-response-types-1_0.html>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC2246] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0",
RFC 2246, DOI 10.17487/RFC2246, January 1999,
<http://www.rfc-editor.org/info/rfc2246>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005,
<http://www.rfc-editor.org/info/rfc3986>.
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[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246,
DOI 10.17487/RFC5246, August 2008,
<http://www.rfc-editor.org/info/rfc5246>.
[RFC5646] Phillips, A., Ed. and M. Davis, Ed., "Tags for Identifying
Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646,
September 2009, <http://www.rfc-editor.org/info/rfc5646>.
[RFC5785] Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known
Uniform Resource Identifiers (URIs)", RFC 5785,
DOI 10.17487/RFC5785, April 2010,
<http://www.rfc-editor.org/info/rfc5785>.
[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, DOI 10.17487/RFC6125, March
2011, <http://www.rfc-editor.org/info/rfc6125>.
[RFC6749] Hardt, D., Ed., "The OAuth 2.0 Authorization Framework",
RFC 6749, DOI 10.17487/RFC6749, October 2012,
<http://www.rfc-editor.org/info/rfc6749>.
[RFC7009] Lodderstedt, T., Ed., Dronia, S., and M. Scurtescu, "OAuth
2.0 Token Revocation", RFC 7009, DOI 10.17487/RFC7009,
August 2013, <http://www.rfc-editor.org/info/rfc7009>.
[RFC7033] Jones, P., Salgueiro, G., Jones, M., and J. Smarr,
"WebFinger", RFC 7033, DOI 10.17487/RFC7033, September
2013, <http://www.rfc-editor.org/info/rfc7033>.
[RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
2014, <http://www.rfc-editor.org/info/rfc7159>.
[RFC7565] Saint-Andre, P., "The 'acct' URI Scheme", RFC 7565,
DOI 10.17487/RFC7565, May 2015,
<http://www.rfc-editor.org/info/rfc7565>.
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[RFC7591] Richer, J., Ed., Jones, M., Bradley, J., Machulak, M., and
P. Hunt, "OAuth 2.0 Dynamic Client Registration Protocol",
RFC 7591, DOI 10.17487/RFC7591, July 2015,
<http://www.rfc-editor.org/info/rfc7591>.
[RFC7636] Sakimura, N., Ed., Bradley, J., and N. Agarwal, "Proof Key
for Code Exchange by OAuth Public Clients", RFC 7636,
DOI 10.17487/RFC7636, September 2015,
<http://www.rfc-editor.org/info/rfc7636>.
[RFC7662] Richer, J., Ed., "OAuth 2.0 Token Introspection",
RFC 7662, DOI 10.17487/RFC7662, October 2015,
<http://www.rfc-editor.org/info/rfc7662>.
[UNICODE] The Unicode Consortium, "The Unicode Standard",
<http://www.unicode.org/versions/latest/>.
[USA15] Davis, M. and K. Whistler, "Unicode Normalization Forms",
Unicode Standard Annex 15, June 2015,
<http://www.unicode.org/reports/tr15/>.
8.2. Informative References
[I-D.ietf-oauth-mix-up-mitigation]
Jones, M., Bradley, J., and N. Sakimura, "OAuth 2.0 Mix-Up
Mitigation", draft-ietf-oauth-mix-up-mitigation-01 (work
in progress), July 2016.
[IANA.well-known]
IANA, "Well-Known URIs",
<http://www.iana.org/assignments/well-known-uris>.
[OpenID.Core]
Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and
C. Mortimore, "OpenID Connect Core 1.0", November 2014,
<http://openid.net/specs/openid-connect-core-1_0.html>.
[OpenID.Discovery]
Sakimura, N., Bradley, J., Jones, M., and E. Jay, "OpenID
Connect Discovery 1.0", November 2014,
<http://openid.net/specs/
openid-connect-discovery-1_0.html>.
[OpenID.Registration]
Sakimura, N., Bradley, J., and M. Jones, "OpenID Connect
Dynamic Client Registration 1.0", November 2014,
<http://openid.net/specs/
openid-connect-registration-1_0.html>.
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Appendix A. Acknowledgements
This specification is based on the OpenID Connect Discovery 1.0
specification, which was produced by the OpenID Connect working group
of the OpenID Foundation.
Review comments resulting in substantive edits to the specification
were made by Brian Campbell, William Denniss, Vladimir Dzhuvinov,
Samuel Erdtman, George Fletcher, Phil Hunt, Tony Nadalin, Justin
Richer, and Hans Zandbelt.
Appendix B. Document History
[[ to be removed by the RFC Editor before publication as an RFC ]]
-03
o Changed term "issuer URL" to "issuer identifier" for terminology
consistency, paralleling the same terminology consistency change
in the mix-up mitigation spec.
-02
o Changed the title to OAuth 2.0 Authorization Server Discovery
Metadata.
o Made "jwks_uri" and "registration_endpoint" OPTIONAL.
o Defined the well-known URI string "/.well-known/oauth-
authorization-server".
o Added security considerations about publishing authorization
server discovery metadata in a standard format.
o Added security considerations about protected resources.
o Added more information to the "grant_types_supported" and
"response_types_supported" definitions.
o Referenced the working group Mix-Up Mitigation draft.
o Changed some example metadata values.
o Acknowledged individuals for their contributions to the
specification.
-01
o Removed WebFinger discovery.
o Clarified the relationship between the issuer identifier URL and
the well-known URI path relative to it at which the discovery
metadata document is located.
-00
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o Created the initial working group version based on draft-jones-
oauth-discovery-01, with no normative changes.
Authors' Addresses
Michael B. Jones
Microsoft
Email: mbj@microsoft.com
URI: http://self-issued.info/
Nat Sakimura
Nomura Research Institute, Ltd.
Email: n-sakimura@nri.co.jp
URI: http://nat.sakimura.org/
John Bradley
Ping Identity
Email: ve7jtb@ve7jtb.com
URI: http://www.thread-safe.com/
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