[Docs] [txt|pdf|xml|html] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits] [IPR]
Versions: 00 01 02 03 04 05 06 07 08 09 10 11
12 13 14 15 16 17 18 19 20 21 22 23
24 25 26 27 28 29 30 31 RFC 6749
Network Working Group E. Hammer-Lahav, Ed.
Internet-Draft Yahoo!
Intended status: Standards Track D. Recordon
Expires: December 31, 2010 Facebook
D. Hardt
Microsoft
June 29, 2010
The OAuth 2.0 Protocol
draft-ietf-oauth-v2-09
Abstract
This specification describes the OAuth 2.0 protocol.
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 December 31, 2010.
Copyright Notice
Copyright (c) 2010 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
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Hammer-Lahav, et al. Expires December 31, 2010 [Page 1]
Internet-Draft OAuth 2.0 June 2010
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Notational Conventions . . . . . . . . . . . . . . . . . . 5
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5
1.3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.4. Client Profiles . . . . . . . . . . . . . . . . . . . . . 9
1.4.1. Web Server . . . . . . . . . . . . . . . . . . . . . . 10
1.4.2. User-Agent . . . . . . . . . . . . . . . . . . . . . . 11
1.4.3. Native Application . . . . . . . . . . . . . . . . . . 13
1.4.4. Autonomous . . . . . . . . . . . . . . . . . . . . . . 14
2. Client Credentials . . . . . . . . . . . . . . . . . . . . . . 14
2.1. Basic Client Credentials . . . . . . . . . . . . . . . . . 15
3. Obtaining End-User Authorization . . . . . . . . . . . . . . . 16
3.1. Authorization Response . . . . . . . . . . . . . . . . . . 18
3.2. Error Response . . . . . . . . . . . . . . . . . . . . . . 20
3.2.1. Error Codes . . . . . . . . . . . . . . . . . . . . . 21
4. Obtaining an Access Token . . . . . . . . . . . . . . . . . . 21
4.1. Access Grant Types . . . . . . . . . . . . . . . . . . . . 22
4.1.1. Authorization Code . . . . . . . . . . . . . . . . . . 23
4.1.2. Resource Owner Basic Credentials . . . . . . . . . . . 23
4.1.3. Assertion . . . . . . . . . . . . . . . . . . . . . . 24
4.1.4. Refresh Token . . . . . . . . . . . . . . . . . . . . 25
4.2. Access Token Response . . . . . . . . . . . . . . . . . . 25
4.3. Error Response . . . . . . . . . . . . . . . . . . . . . . 27
4.3.1. Error Codes . . . . . . . . . . . . . . . . . . . . . 27
5. Accessing a Protected Resource . . . . . . . . . . . . . . . . 28
5.1. Authenticated Requests . . . . . . . . . . . . . . . . . . 29
5.1.1. The Authorization Request Header Field . . . . . . . . 29
5.1.2. URI Query Parameter . . . . . . . . . . . . . . . . . 29
5.1.3. Form-Encoded Body Parameter . . . . . . . . . . . . . 30
5.2. The WWW-Authenticate Response Header Field . . . . . . . . 31
5.2.1. Error Codes . . . . . . . . . . . . . . . . . . . . . 32
6. Extensibility . . . . . . . . . . . . . . . . . . . . . . . . 33
6.1. Defining New Client Credentials Types . . . . . . . . . . 33
6.2. Defining New Endpoint Parameters . . . . . . . . . . . . . 33
6.3. Defining New Header Field Parameters . . . . . . . . . . . 34
6.4. Defining New Access Grant Types . . . . . . . . . . . . . 34
7. Security Considerations . . . . . . . . . . . . . . . . . . . 34
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 34
8.1. The OAuth Parameters Registry . . . . . . . . . . . . . . 34
8.1.1. Registration Template . . . . . . . . . . . . . . . . 35
8.1.2. Example . . . . . . . . . . . . . . . . . . . . . . . 35
Appendix A. Examples . . . . . . . . . . . . . . . . . . . . . . 36
Appendix B. Contributors . . . . . . . . . . . . . . . . . . . . 36
Appendix C. Acknowledgements . . . . . . . . . . . . . . . . . . 36
Appendix D. Document History . . . . . . . . . . . . . . . . . . 36
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Hammer-Lahav, et al. Expires December 31, 2010 [Page 2]
Internet-Draft OAuth 2.0 June 2010
9.1. Normative References . . . . . . . . . . . . . . . . . . . 40
9.2. Informative References . . . . . . . . . . . . . . . . . . 41
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 42
Hammer-Lahav, et al. Expires December 31, 2010 [Page 3]
Internet-Draft OAuth 2.0 June 2010
1. Introduction
With the increasing use of distributed web services and cloud
computing, third-party applications require access to server-hosted
resources. These resources are usually protected and require
authentication using the resource owner's credentials (typically a
username and password).
In the traditional client-server authentication model, the client
accesses a protected resource on the server by presenting the
resource owner's credentials in order to authenticate and gain
access. OAuth introduces a third role to the traditional model: the
resource owner. In OAuth, the client (which is usually not the
resource owner, but is acting on its behalf) requests access to
resources controlled by the resource owner and hosted by the resource
server.
In addition to removing the need for resource owners to share their
credentials, resource owners require the ability to restrict access
to a limited subset of the resources they control, to limit access
duration, or to limit access to the methods supported by these
resources.
Instead of using the resource owner's credentials to access protected
resources, clients obtain an access token (a string which denotes a
specific scope, duration, and other attributes). The format and
structure of access tokens is beyond the scope of this specification.
Tokens are issued to third-party clients by an authorization server
with the approval of the resource owner. The client uses the access
token to access the protected resources hosted by the resource
server. The interaction between the authorization server and
resource server is beyond the scope of this specification.
For example, a web user (resource owner) can grant a printing service
(client) access to her protected photos stored at a photo sharing
service (resource server), without sharing her username and password
with the printing service. Instead, she authenticates directly with
the photo sharing service (authorization server) which issues the
printing service delegation-specific credentials (token).
This specification defines the use of OAuth over HTTP [RFC2616] (or
HTTP over TLS as defined by [RFC2818]). Other specifications may
extend it for use with other transport protocols.
Hammer-Lahav, et al. Expires December 31, 2010 [Page 4]
Internet-Draft OAuth 2.0 June 2010
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].
This document uses the Augmented Backus-Naur Form (ABNF) notation of
[I-D.ietf-httpbis-p1-messaging]. Additionally, the following rules
are included from [RFC2617]: realm, auth-param; from [RFC3986]: URI-
Reference; and from [I-D.ietf-httpbis-p1-messaging]: OWS, RWS, and
quoted-string.
Unless otherwise noted, all the protocol parameter names and values
are case sensitive.
1.2. Terminology
protected resource
An access-restricted resource which can be obtained using an
OAuth-authenticated request.
resource server
A server capable of accepting and responding to protected
resource requests.
client
An application obtaining authorization and making protected
resource requests.
resource owner
An entity capable of granting access to a protected resource.
end-user
A human resource owner.
token
A string representing an access authorization issued to the
client. The string is usually opaque to the client and can
self-contain the authorization information in a verifiable
manner (i.e. signed), or denotes an identifier used to retrieve
the information. Tokens represent a specific scope, duration,
and other authorization attributes granted by the resource
owner and enforced by the resource server and authorization
servers.
Hammer-Lahav, et al. Expires December 31, 2010 [Page 5]
Internet-Draft OAuth 2.0 June 2010
access token
A token used by the client to make authenticated requests
on behalf of the resource owner.
refresh token
A token used by the client to obtain a new access token
without having to involve the resource owner.
authorization code A short-lived token representing the access
grant provided by the end-user. The authorization code
is used to obtain an access token and a refresh token.
authorization server
A server capable of issuing tokens after successfully
authenticating the resource owner and obtaining authorization.
The authorization server may be the same server as the resource
server, or a separate entity.
end-user authorization endpoint
The authorization server's HTTP endpoint capable of
authenticating the end-user and obtaining authorization. The
end-user authorization endpoint is described in Section 3.
token endpoint
The authorization server's HTTP endpoint capable of issuing
tokens and refreshing expired tokens. The token endpoint is
described in Section 4.
client identifier
An unique identifier issued to the client to identify itself to
the authorization server. Client identifiers may have a
matching secret. The client identifier is described in
Section 2.
1.3. Overview
OAuth provides a method for clients to access a protected resource on
behalf of a resource owner. Before a client can access a protected
resource, it must first obtain authorization from the resource owner,
then exchange the access grant for an access token (representing the
grant's scope, duration, and other attributes). The client accesses
the protected resource by presenting the access token to the resource
server.
Hammer-Lahav, et al. Expires December 31, 2010 [Page 6]
Internet-Draft OAuth 2.0 June 2010
+--------+ +---------------+
| |--(A)-- Authorization Request --->| Resource |
| | | Owner |
| |<-(B)------ Access Grant ---------| |
| | +---------------+
| |
| | Client Credentials & +---------------+
| |--(C)------ Access Grant -------->| Authorization |
| Client | | Server |
| |<-(D)------ Access Token ---------| |
| | (w/ Optional Refresh Token) +---------------+
| |
| | +---------------+
| |--(E)------ Access Token -------->| Resource |
| | | Server |
| |<-(F)---- Protected Resource -----| |
+--------+ +---------------+
Figure 1: Abstract Protocol Flow
The abstract flow illustrated in Figure 1 includes the following
steps:
(A) The client requests authorization from the resource owner. The
client should not interact directly with the resource owner
(since that would expose the resource owner's credentials to the
client), but instead request authorization via an authorization
server or other entities. For example, the client directs the
resource owner to the authorization server which in turn issues
it an access grant. When unavoidable, the client interacts
directly with the end-user, asking for the end-user's username
and password. If the client is acting autonomously, the
authorization request is beyond the scope of this specification.
(B) The client is issued an access grant which represents the
authorization provided by the resource owner. The access grant
can be expressed as:
* Authorization code - an access grant obtained via an
authorization server. The process used to obtain an
authorization code utilized the end-user's user-agent and is
described in Section 3.
* Assertion - an access grant obtained using a different trust
framework. Assertions enable the client to utilize existing
trust relationships to obtain an access token. They provide
a bridge between OAuth and other trust frameworks. The
Hammer-Lahav, et al. Expires December 31, 2010 [Page 7]
Internet-Draft OAuth 2.0 June 2010
access grant represented by an assertion depends on the
assertion type, its content, and how it was issued, which are
beyond the scope of this specification.
* Resource owner basic credentials - obtained when interacting
directly with a resource-owner. Resource owner basic
credentials (i.e. a username and password) should only be
used when there is a high degree of trust between the
resource owner and the client (e.g. its computer operating
system or a highly privileged application). However, unlike
the HTTP Basic authentication scheme defined in [RFC2617],
the resource owner's credentials are used for a single
request and are exchanged for an access token and refresh
token. This eliminates the need for the client to store the
resource-owner's credentials for future use.
(C) The client requests an access token by authenticating with the
authorization server, and presenting the access grant. The
token request is described in Section 4.
(D) The authorization server validates the client credentials and
the access grant, and issues an access token with an optional
refresh token. Access tokens usually have a shorter lifetime
than the access grant. Refresh tokens usually have a lifetime
equal to the duration of the access grant. When an access token
expires, the refresh token is used to obtain a new access token
without having to request another access grant from the resource
owner.
(E) The client makes a protected resource request to the resource
server, and presents the access token in order to gain access.
Accessing a protected resource is described in Section 5.
(F) The resource server validates the access token, and if valid,
serves the request.
When the client is acting on its own behalf (the client is also the
resource owner), the client does not obtain an access grant. The
simplified protocol flow is illustrated in Figure 2:
Hammer-Lahav, et al. Expires December 31, 2010 [Page 8]
Internet-Draft OAuth 2.0 June 2010
+--------+ +---------------+
| |--(C)--- Client Credentials ----->| Authorization |
| | | Server |
| |<-(D)------ Access Token ---------| |
| | (w/ Optional Refresh Token) +---------------+
| Client |
| | +---------------+
| |--(E)------ Access Token -------->| Resource |
| | | Server |
| |<-(F)---- Protected Resource -----| |
+--------+ +---------------+
Figure 2: Protocol Flow for Client Acting On Its Own Behalf
When the client uses the user-agent profile (described in
Section 1.4.2), the authorization request results in an access token,
as illustrated in Figure 3:
+--------+ +----------+ +---------------+
| |--(A)-- Authorization --+- -+-->| |
| | Request | Resource | | Authorization |
| | | Owner | | Server |
| |<-(D)-- Access Token ---+- -+---| |
| | +----------+ +---------------+
| Client |
| | +---------------+
| |--(E)-------- Access Token ----------->| Resource |
| | | Server |
| |<-(F)------ Protected Resource --------| |
+--------+ +---------------+
Figure 3: Indirect Access Grant Protocol Flow
1.4. Client Profiles
OAuth supports a wide range of client types by providing a rich and
extensible framework for establishing authorization and exchanging it
for an access token. The methods detailed in this specification were
designed to accommodate four client types: web servers, user-agents,
native applications, and autonomous clients. Additional
authorization flows and client profiles may be defined by other
specifications to cover additional scenarios and client types.
Hammer-Lahav, et al. Expires December 31, 2010 [Page 9]
Internet-Draft OAuth 2.0 June 2010
1.4.1. Web Server
The web server profile is suitable for clients capable of interacting
with the end-user's user-agent (typically a web browser) and capable
of receiving incoming requests from the authorization server (capable
of acting as an HTTP server).
+----------+ Client Identifier +---------------+
| -+----(A)--- & Redirect URI ------>| |
| End-user | | Authorization |
| at |<---(B)-- User authenticates --->| Server |
| Browser | | |
| -+----(C)-- Authorization Code ---<| |
+-|----|---+ +---------------+
| | ^ v
(A) (C) | |
| | | |
^ v | |
+---------+ | |
| |>---(D)-- Client Credentials, --------' |
| Web | Authorization Code, |
| Client | & Redirect URI |
| | |
| |<---(E)----- Access Token -------------------'
+---------+ (w/ Optional Refresh Token)
Figure 4: Web Server Flow
The web server flow illustrated in Figure 4 includes the following
steps:
(A) The web client initiates the flow by redirecting the end-user's
user-agent to the end-user authorization endpoint as described
in Section 3 The client includes its client identifier,
requested scope, local state, and a redirect URI to which the
authorization server will send the end-user back once access is
granted (or denied).
(B) The authorization server authenticates the end-user (via the
user-agent) and establishes whether the end-user grants or
denies the client's access request.
(C) Assuming the end-user granted access, the authorization server
redirects the user-agent back to the client to the redirection
URI provided earlier. The authorization includes an
authorization code for the client to use to obtain an access
Hammer-Lahav, et al. Expires December 31, 2010 [Page 10]
Internet-Draft OAuth 2.0 June 2010
token.
(D) The client requests an access token from the authorization
server by authenticating and including the authorization code
received in the previous step as described in Section 4.
(E) The authorization server validates the client credentials and
the authorization code and responds back with the access token.
1.4.2. User-Agent
The user-agent profile is suitable for client applications residing
in a user-agent, typically implemented in a browser using a scripting
language such as JavaScript. These clients cannot keep client
secrets confidential and the authentication of the client is based on
the user-agent's same-origin policy.
Unlike other profiles in which the client makes a separate end-user
authorization request and an access token requests, the client
receives the access token as a result of the end-user authorization
request in the form of an HTTP redirection. The client requests the
authorization server to redirect the user-agent to another web server
or local resource accessible to the user-agent which is capable of
extracting the access token from the response and passing it to the
client.
This user-agent profile does not utilize the client secret since the
client executables reside on the end-user's computer or device which
makes the client secret accessible and exploitable. Because the
access token is encoded into the redirection URI, it may be exposed
to the end-user and other applications residing on the computer or
device.
Hammer-Lahav, et al. Expires December 31, 2010 [Page 11]
Internet-Draft OAuth 2.0 June 2010
+----------+ Client Identifier +----------------+
| |>---(A)-- & Redirection URI --->| |
| | | |
End <--+ - - - +----(B)-- User authenticates -->| Authorization |
User | | | Server |
| |<---(C)--- Redirect URI -------<| |
| Client | with Access Token | |
| in | in Fragment +----------------+
| Browser |
| | +----------------+
| |>---(D)--- Redirect URI ------->| |
| | without Fragment | Web Server |
| | | with Client |
| (F) |<---(E)--- Web Page with ------<| Resource |
| Access | Script | |
| Token | +----------------+
+----------+
Figure 5: User-Agent Flow
The user-agent flow illustrated in Figure 5 includes the following
steps:
(A) The client sends the user-agent to the end-user authorization
endpoint as described in Section 3. The client includes its
client identifier, requested scope, local state, and a redirect
URI to which the authorization server will send the end-user
back once authorization is granted (or denied).
(B) The authorization server authenticates the end-user (via the
user-agent) and establishes whether the end-user grants or
denies the client's access request.
(C) If the end-user granted access, the authorization server
redirects the user-agent to the redirection URI provided
earlier. The redirection URI includes the access token in the
URI fragment.
(D) The user-agent follows the redirection instructions by making a
request to the web server which does not include the fragment.
The user-agent retains the fragment information locally.
(E) The web server returns a web page (typically an HTML page with
an embedded script) capable of accessing the full redirection
URI including the fragment retained by the user-agent, and
extracting the access token (and other parameters) contained in
the fragment.
Hammer-Lahav, et al. Expires December 31, 2010 [Page 12]
Internet-Draft OAuth 2.0 June 2010
(F) The user-agent executes the script provided by the web server
locally, which extracts the access token and passes it to the
client.
1.4.3. Native Application
Native application are clients running as native code on the end-
user's computer or device (i.e. executing outside a user-agent or as
a desktop program). These clients are often capable of interacting
with (or embedding) the end-user's user-agent but are limited in how
such interaction affects their end-user experience. In many cases,
native applications are incapable of receiving direct callback
requests from the server (e.g. firewall, operating system
restrictions).
Native application clients can be implemented in different ways based
on their requirements and desired end-user experience. Native
application clients can:
o Utilize the end-user authorization endpoint as described in
Section 3 by launching an external user-agent. The client can
capture the response by providing a redirection URI with a custom
URI scheme (registered with the operating system to invoke the
client application), or by providing a redirection URI pointing to
a server-hosted resource under the client's control which makes
the response available to the client (e.g. using the window title
or other locations accessible from outside the user-agent).
o Utilize the end-user authorization endpoint as described in
Section 3 by using an embedded user-agent. The client obtains the
response by directly communicating with the embedded user-agent.
o Prompt end-users for their basic credentials (username and
password) and use them directly to obtain an access token. This
is generally discouraged as it hands the end-user's password
directly to the 3rd party and is limited to basic credentials.
When choosing between launching an external browser and an embedded
user-agent, developers should consider the following:
o External user-agents may improve completion rate as the end-user
may already be logged-in and not have to re-authenticate.
o Embedded user-agents often offer a better end-user flow, as they
remove the need to switch context and open new windows.
o Embedded user-agents pose a security challenge because users are
authenticating in an unidentified window without access to the
Hammer-Lahav, et al. Expires December 31, 2010 [Page 13]
Internet-Draft OAuth 2.0 June 2010
visual protections offered by many user-agents.
1.4.4. Autonomous
Autonomous clients utilize an existing trust relationship or
framework to establish authorization. Autonomous clients can be
implemented in different ways based on their requirements and the
existing trust framework they rely upon. Autonomous clients can:
o Obtain an access token by authenticating with the authorization
server using their client credentials. The scope of the access
token is limited to the protected resources under the control of
the client, or that of another resource owner previously arranged
with the authorization server.
o Use an existing access grant expressed as an assertion using an
assertion format supported by the authorization server. Using
assertions requires the client to obtain a assertion (such as a
SAML [OASIS.saml-core-2.0-os] assertion) from an assertion issuer
or to self-issue an assertion. The assertion format, the process
by which the assertion is obtained, and the method of validating
the assertion are defined by the assertion issuer and the
authorization server, and are beyond the scope of this
specification.
2. Client Credentials
When interacting with the authorization server, the client identifies
itself using a set of client credentials. The client credentials
include a client identifier and MAY include a secret or other means
for the authorization server to authenticate the client.
The means through which the client obtains its credentials are beyond
the scope of this specification, but usually involve registration
with the authorization server. [[ OAuth Discovery provides one way of
obtaining basic client credentials ]]
Due to the nature of some clients, authorization servers SHOULD NOT
make assumptions about the confidentiality of client credentials
without establishing trust with the client operator. Authorization
servers SHOULD NOT issue client secrets to clients incapable of
keeping their secrets confidential.
This specification provides one mechanism for authenticating the
client using a set of basic client credentials. The authorization
server MAY authenticate the client using any desired authentication
scheme.
Hammer-Lahav, et al. Expires December 31, 2010 [Page 14]
Internet-Draft OAuth 2.0 June 2010
The client MUST NOT include more than one set of client credentials
with each request, and MUST NOT utilize more than one mechanism to
authenticate each request (regardless whether the credentials are
identical).
2.1. Basic Client Credentials
The basic client credentials include a client identifier and an
OPTIONAL matching shared symmetric secret. The client identifier and
secret are included in the request using the HTTP Basic
authentication scheme as defined in [RFC2617] by including the client
identifier as the username and secret as the password.
For example (line breaks are for display purposes only):
POST /token HTTP/1.1
Host: server.example.com
Authorization: Basic czZCaGRSa3F0MzpnWDFmQmF0M2JW
Content-Type: application/x-www-form-urlencoded
type=web-server&code=i1WsRn1uB1&
redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
Alternatively, the client MAY include the credentials using the
following request parameters:
client_id
REQUIRED. The client identifier.
client_secret REQUIRED if the client identifier has a matching
secret.
For example (line breaks are for display purposes only):
POST /token HTTP/1.1
Host: server.example.com
Content-Type: application/x-www-form-urlencoded
type=web-server&client_id=s6BhdRkqt3&
client_secret=gX1fBat3bV&code=i1WsRn1uB1&
redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
The authorization server MUST accept the client credentials using
both the request parameters, and the HTTP Basic authentication
Hammer-Lahav, et al. Expires December 31, 2010 [Page 15]
Internet-Draft OAuth 2.0 June 2010
scheme. The authorization server MAY support additional
authentication schemes suitable for the transmission of a username
and password.
3. Obtaining End-User Authorization
When the client interacts with an end-user, the end-user MUST first
grant the client authorization to access its protected resources.
Once obtained, the end-user access grant is expressed as an
authorization code which the client uses to obtain an access token.
To obtain an end-user authorization, the client sends the end-user to
the end-user authorization endpoint.
At the end-user authorization endpoint, the end-user first
authenticates with the authorization server, and then grants or
denies the access request. The way in which the authorization server
authenticates the end-user (e.g. username and password login, OpenID,
session cookies) and in which the authorization server obtains the
end-user's authorization, including whether it uses a secure channel
such as TLS, is beyond the scope of this specification. However, the
authorization server MUST first verify the identity of the end-user.
The location of the end-user authorization endpoint can be found in
the service documentation, or can be obtained by using [[ OAuth
Discovery ]]. The end-user authorization endpoint URI MAY include a
query component as defined by [RFC3986] section 3, which must be
retained when adding additional query parameters.
Since requests to the end-user authorization endpoint result in user
authentication and the transmission of sensitive information, the
authorization server SHOULD require the use of a transport-layer
security mechanism such as TLS when sending requests to the end-user
authorization endpoint.
In order to direct the end-user's user-agent to the authorization
server, the client constructs the request URI by adding the following
parameters to the end-user authorization endpoint URI query component
using the "application/x-www-form-urlencoded" format as defined by
[W3C.REC-html401-19991224]:
response_type
REQUIRED. The requested response: an access token, an
authorization code, or both. The parameter value MUST be set
to "token" for requesting an access token, "code" for
requesting an authorization code, or "code-and-token" to
request both. The authorization server MAY decline to provide
one or more of these response types. [[ The 'code-and-token'
Hammer-Lahav, et al. Expires December 31, 2010 [Page 16]
Internet-Draft OAuth 2.0 June 2010
type is pending use cases and may be removed for the
specification ]]
client_id
REQUIRED. The client identifier as described in Section 2.
redirect_uri
REQUIRED, unless a redirection URI has been established between
the client and authorization server via other means. An
absolute URI to which the authorization server will redirect
the user-agent to when the end-user authorization step is
completed. The authorization server SHOULD require the client
to pre-register their redirection URI.
scope
OPTIONAL. The scope of the access request expressed as a list
of space-delimited strings. The value of the "scope" parameter
is defined by the authorization server. If the value contains
multiple space-delimited strings, their order does not matter,
and each string adds an additional access range to the
requested scope.
state
OPTIONAL. An opaque value used by the client to maintain state
between the request and callback. The authorization server
includes this value when redirecting the user-agent back to the
client.
The client directs the end-user to the constructed URI using an HTTP
redirection response, or by other means available to it via the end-
user's user-agent. The request MUST use the HTTP "GET" method.
For example, the client directs the end-user's user-agent to make the
following HTTP request using transport-layer security (line breaks
are for display purposes only):
GET /authorize?response_type=code&client_id=s6BhdRkqt3&
redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb HTTP/1.1
Host: server.example.com
If the client has previously registered a redirection URI with the
authorization server, the authorization server MUST verify that the
redirection URI received matches the registered URI associated with
the client identifier. [[ provide guidance on how to perform matching
]]
Hammer-Lahav, et al. Expires December 31, 2010 [Page 17]
Internet-Draft OAuth 2.0 June 2010
Parameters sent without a value MUST be treated as if they were
omitted from the request.
The authorization server validates the request to ensure all required
parameters are present and valid. If the request is invalid, the
authorization server immediately redirects the user-agent back to the
client using the redirection URI provided with the appropriate error
code as described in Section 3.2.
The authorization server authenticates the end-user and obtains an
authorization decision (by asking the end-user or by establishing
approval via other means). When a decision has been established, the
authorization server directs the end-user's user-agent to the
provided client redirection URI using an HTTP redirection response,
or by other means available to it via the end-user's user-agent.
3.1. Authorization Response
If the end-user grants the access request, the authorization server
issues an access token, an authorization code, or both, and delivers
them to the client by adding the following parameters to the
redirection URI (as described below):
code
REQUIRED if the response type is "token" or "code-and-token",
otherwise MUST NOT be included. The authorization code
generated by the authorization server. The authorization code
SHOULD expire shortly after it is issued. The authorization
server MUST invalidate the authorization code after a single
usage. The authorization code is bound to the client
identifier and redirection URI.
access_token
REQUIRED if the response type is "token" or "code-and-token",
otherwise MUST NOT be included. The access token.
expires_in
OPTIONAL. The duration in seconds of the access token lifetime
if an access token is included. For example, the value "3600"
denotes that the access token will expire in one hour from the
time the response was generated by the authorization server.
scope
OPTIONAL. The scope of the access token as a list of space-
delimited strings if an access token is included. The value of
the "scope" parameter is defined by the authorization server.
If the value contains multiple space-delimited strings, their
order does not matter, and each string adds an additional
Hammer-Lahav, et al. Expires December 31, 2010 [Page 18]
Internet-Draft OAuth 2.0 June 2010
access range to the requested scope.
state
REQUIRED if the "state" parameter was present in the client
authorization request. Set to the exact value received from
the client.
The method in which the authorization server adds the parameter to
the redirection URI is determined by the response type requested by
the client in the authorization request using the "response_type"
parameter.
If the response type is "code", the authorization server adds the
parameters to the redirection URI query component using the
"application/x-www-form-urlencoded" format as defined by
[W3C.REC-html401-19991224].
For example, the authorization server redirects the end-user's user-
agent by sending the following HTTP response:
HTTP/1.1 302 Found
Location: https://client.example.com/cb?code=i1WsRn1uB1
If the response type is "token", the authorization server adds the
parameters to the redirection URI fragment component using the
"application/x-www-form-urlencoded" format as defined by
[W3C.REC-html401-19991224].
For example, the authorization server redirects the end-user's user-
agent by sending the following HTTP response:
HTTP/1.1 302 Found
Location: http://example.com/rd#access_token=FJQbwq9&expires_in=3600
If the response type is "code-and-token", the authorization server
adds the "code" and "state" parameters to the redirection URI query
component and the "access_token", "scope", and "expires_in" to the
redirection URI fragment using the
"application/x-www-form-urlencoded" format as defined by
[W3C.REC-html401-19991224].
Hammer-Lahav, et al. Expires December 31, 2010 [Page 19]
Internet-Draft OAuth 2.0 June 2010
For example, the authorization server redirects the end-user's user-
agent by sending the following HTTP response (line breaks are for
display purposes only):
HTTP/1.1 302 Found
Location: http://example.com/rd?code=i1WsRn1uB1
#access_token=FJQbwq9&expires_in=3600
The sizes of tokens and other values received from the authorization
server, are left undefined by this specification. Clients should
avoid making assumptions about value sizes. Servers should document
the expected size of any value they issue.
3.2. Error Response
If the end-user denies the access request or if the request is
invalid, the authorization server informs the client by adding the
following parameters to the redirection URI query component using the
"application/x-www-form-urlencoded" format as defined by
[W3C.REC-html401-19991224]:
error
REQUIRED. A single error code as described in Section 3.2.1.
error_description OPTIONAL. A human-readable text providing
additional information, used to assist in the understanding and
resolution of the error occurred.
error_uri OPTIONAL. A URI identifying a human-readable web page
with information about the error, used to provide the end-user
with additional information about the error.
state
REQUIRED if the "state" parameter was present in the client
authorization request. Set to the exact value received from
the client.
For example, the authorization server redirects the end-user's user-
agent by sending the following HTTP response:
HTTP/1.1 302 Found
Location: https://client.example.com/cb?error=access-denied
Hammer-Lahav, et al. Expires December 31, 2010 [Page 20]
Internet-Draft OAuth 2.0 June 2010
3.2.1. Error Codes
The authorization server includes one of the following error codes
with the error response:
invalid-request
The request is missing a required parameter, includes an
unknown parameter or parameter value, or is otherwise
malformed.
invalid-client-id
The client identifier provided is invalid.
unauthorized-client
The client is not authorized to use the requested response
type.
redirect-uri-mismatch
The redirection URI provided does not match a pre-registered
value.
access-denied
The end-user or authorization server denied the request.
unsupported-response-type
The requested response type is not supported by the
authorization server.
invalid_scope
The requested scope is invalid, unknown, or malformed.
[[ Add mechanism for extending error codes ]]
4. Obtaining an Access Token
The client obtains an access token by authenticating with the
authorization server and presenting its access grant.
After establishing resource owner authorization, clients request an
access token from the authorization server's token endpoint. When
requesting an access token, the client authenticates with the
authorization server and includes the access grant (in the form of an
authorization code, resource owner credentials, an assertion, or a
refresh token).
The location of the token endpoint can be found in the service
documentation, or can be obtained by using [[ OAuth Discovery ]].
Hammer-Lahav, et al. Expires December 31, 2010 [Page 21]
Internet-Draft OAuth 2.0 June 2010
The token endpoint URI MAY include a query component.
Since requests to the token endpoint result in the transmission of
plain 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 token endpoints.
Servers MUST support TLS 1.2 as defined in [RFC5246], and MAY support
additional transport-layer security mechanisms.
The client requests an access token by constructing a token request
and making an HTTP "POST" request. The client constructs the request
URI by adding its client credentials to the request as described in
Section 2, and includes the following parameters using the
"application/x-www-form-urlencoded" format in the HTTP request
entity-body:
grant_type
REQUIRED. The access grant type included in the request.
Value MUST be one of "authorization-code", "basic-credentials",
"assertion", "refresh-token", or "none".
scope
OPTIONAL. The scope of the access request expressed as a list
of space-delimited strings. The value of the "scope" parameter
is defined by the authorization server. If the value contains
multiple space-delimited strings, their order does not matter,
and each string adds an additional access range to the
requested scope. If the access grant being used already
represents an approved scope (e.g. authorization code,
assertion), the requested scope MUST be equal or lesser than
the scope previously granted.
In addition, the client MUST include the appropriate parameters
listed for the selected access grant type as described in
Section 4.1.
Parameters sent without a value MUST be treated as if they were
omitted from the request.
4.1. Access Grant Types
The client requests an access token using one of the four types of
access grants: authorization code, basic credentials, assertion, or
refresh token.
When requesting an access token using the "none" access grant type
(no access grant is included), the client is requesting access to the
protected resources under its control, or those of another resource
Hammer-Lahav, et al. Expires December 31, 2010 [Page 22]
Internet-Draft OAuth 2.0 June 2010
owner which has been previously arranged with the authorization
server (the method of which is beyond the scope of this
specification).
4.1.1. Authorization Code
The client includes the authorization code using the
"authorization-code" access grant type and the following parameters:
code
REQUIRED. The authorization code received from the
authorization server.
redirect_uri
REQUIRED. The redirection URI used in the initial request.
For example, the client makes the following HTTP request using
transport-layer security (line breaks are for display purposes only):
POST /token HTTP/1.1
Host: server.example.com
Content-Type: application/x-www-form-urlencoded
grant_type=authorization-code&client_id=s6BhdRkqt3&
client_secret=gX1fBat3bV&code=i1WsRn1uB1&
redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb
The authorization server MUST verify that the authorization code,
client identity, client secret, and redirection URI are all valid and
match its stored association. If the request is valid, the
authorization server issues a successful response as described in
Section 4.2.
4.1.2. Resource Owner Basic Credentials
The client includes the resource owner credentials using the
"basic-credentials" access grant type and the following parameters:
[[ add internationalization consideration for username and password
]]
username
REQUIRED. The end-user's username.
Hammer-Lahav, et al. Expires December 31, 2010 [Page 23]
Internet-Draft OAuth 2.0 June 2010
password
REQUIRED. The end-user's password.
For example, the client makes the following HTTP request using
transport-layer security (line breaks are for display purposes only):
POST /token HTTP/1.1
Host: server.example.com
Content-Type: application/x-www-form-urlencoded
grant_type=basic-credentials&client_id=s6BhdRkqt3&
client_secret=47HDu8s&username=johndoe&password=A3ddj3w
The authorization server MUST validate the client credentials and
end-user credentials and if valid issues an access token response as
described in Section 4.2.
4.1.3. Assertion
The client includes the assertion using the "assertion" access grant
type and the following parameters:
assertion_type
REQUIRED. The format of the assertion as defined by the
authorization server. The value MUST be an absolute URI.
assertion
REQUIRED. The assertion.
For example, the client makes the following HTTP request using
transport-layer security (line breaks are for display purposes only):
POST /token HTTP/1.1
Host: server.example.com
Content-Type: application/x-www-form-urlencoded
grant_type=assertion&client_id=s6BhdRkqt3&client_secret=diejdsks&
assertion_type=urn%3Aoasis%3Anames%3Atc%3ASAML%3A2.0%3Aassertion&
assertion=PHNhbWxwOl...[omitted for brevity]...ZT4%3D
The authorization server MUST validate the assertion and if valid
issues an access token response as described in Section 4.2. The
authorization server SHOULD NOT issue a refresh token.
Hammer-Lahav, et al. Expires December 31, 2010 [Page 24]
Internet-Draft OAuth 2.0 June 2010
Authorization servers SHOULD issue access tokens with a limited
lifetime and require clients to refresh them by requesting a new
access token using the same assertion if it is still valid.
Otherwise the client MUST obtain a new valid assertion.
4.1.4. Refresh Token
The client includes the refresh token using the "refresh-token"
access grant type and the following parameter:
refresh_token
REQUIRED. The refresh token associated with the access token
to be refreshed.
For example, the client makes the following HTTP request using
transport-layer security (line break are for display purposes only):
POST /token HTTP/1.1
Host: server.example.com
Content-Type: application/x-www-form-urlencoded
grant_type=refresh-token&client_id=s6BhdRkqt3&
client_secret=8eSEIpnqmM&refresh_token=n4E9O119d
The authorization server MUST verify the client credentials, the
validity of the refresh token, and that the resource owner's
authorization is still valid. If the request is valid, the
authorization server issues an access token response as described in
Section 4.2. The authorization server MAY issue a new refresh token.
4.2. Access Token Response
After receiving and verifying a valid and authorized access token
request from the client, the authorization server issues the access
token and optional refresh token, and constructs the response by
adding the following parameters to the entity body of the HTTP
response with a 200 (OK) status code:
The token response contains the following parameters:
access_token
REQUIRED. The access token issued by the authorization server.
Hammer-Lahav, et al. Expires December 31, 2010 [Page 25]
Internet-Draft OAuth 2.0 June 2010
expires_in
OPTIONAL. The duration in seconds of the access token
lifetime. For example, the value "3600" denotes that the
access token will expire in one hour from the time the response
was generated by the authorization server.
refresh_token
OPTIONAL. The refresh token used to obtain new access tokens
using the same end-user access grant as described in
Section 4.1.4.
scope
OPTIONAL. The scope of the access token as a list of space-
delimited strings. The value of the "scope" parameter is
defined by the authorization server. If the value contains
multiple space-delimited strings, their order does not matter,
and each string adds an additional access range to the
requested scope.
The parameters are including in the entity body of the HTTP response
using the "application/json" media type as defined by [RFC4627]. The
parameters are serialized into a JSON structure by adding each
parameter at the highest structure level. Parameter names and string
values are included as JSON strings. Numerical values are included
as JSON numbers.
The authorization server MUST include the HTTP "Cache-Control"
response header field with a value of "no-store" in any response
containing tokens, secrets, or other sensitive information.
For example:
HTTP/1.1 200 OK
Content-Type: application/json
Cache-Control: no-store
{
"access_token":"SlAV32hkKG",
"expires_in":3600,
"refresh_token":"8xLOxBtZp8"
}
The sizes of tokens and other values received from the authorization
server, are left undefined by this specification. Clients should
avoid making assumptions about value sizes. Servers should document
the expected size of any value they issue.
Hammer-Lahav, et al. Expires December 31, 2010 [Page 26]
Internet-Draft OAuth 2.0 June 2010
4.3. Error Response
If the token request is invalid or unauthorized, the authorization
server constructs the response by adding the following parameter to
the entity body of the HTTP response using the "application/json"
media type:
error
REQUIRED. A single error code as described in Section 4.3.1.
error_description OPTIONAL. A human-readable text providing
additional information, used to assist in the understanding and
resolution of the error occurred.
error_uri OPTIONAL. A URI identifying a human-readable web page
with information about the error, used to provide the end-user
with additional information about the error.
For example:
HTTP/1.1 400 Bad Request
Content-Type: application/json
Cache-Control: no-store
{
"error":"invalid-request"
}
If the client provided invalid credentials using an HTTP
authentication scheme via the "Authorization" request header field,
the authorization server MUST respond with the HTTP 401
(Unauthorized) status code. Otherwise, the authorization server
SHALL respond with the HTTP 400 (Bad Request) status code.
4.3.1. Error Codes
The authorization server includes one of the following error codes
with the error response:
invalid-request
The request is missing a required parameter, includes an
unknown parameter or parameter value, repeats a parameter,
includes multiple credentials, utilizes more than one mechanism
for authenticating the client, or is otherwise malformed.
Hammer-Lahav, et al. Expires December 31, 2010 [Page 27]
Internet-Draft OAuth 2.0 June 2010
invalid-client-credentials
The client identifier provided is invalid, the client failed to
authenticate, or the client provided multiple client
credentials.
unauthorized-client
The client is not authorized to use the access grant type
provided.
invalid-grant
The provided access grant is invalid, expired, or revoked (e.g.
invalid assertion, expired authorization token, bad end-user
basic credentials, or mismatching authorization code and
redirection URI).
unsupported-grant-type
The access grant included - its type or another attribute - is
not supported by the authorization server.
invalid-scope
The requested scope is invalid, unknown, malformed, or exceeds
the previously granted scope.
[[ Add mechanism for extending error codes ]]
5. Accessing a Protected Resource
Clients access protected resources by presenting an access token to
the resource server. Access tokens act as bearer tokens, where the
token string acts as a shared symmetric secret. This requires
treating the access token with the same care as other secrets (e.g.
end-user passwords). Access tokens SHOULD NOT be sent in the clear
over an insecure channel.
However, when it is necessary to transmit access tokens in the clear
without a secure channel, authorization servers SHOULD issue access
tokens with limited scope and lifetime to reduce the potential risk
from a compromised access token.
Clients MUST NOT make authenticated requests with an access token to
unfamiliar resource servers, regardless of the presence of a secure
channel.
The resource server MUST validate the access token and ensure it has
not expired and that its scope covers the requested resource. The
methods used by the resource server to validate the access token are
beyond the scope of this specification, but generally involve an
Hammer-Lahav, et al. Expires December 31, 2010 [Page 28]
Internet-Draft OAuth 2.0 June 2010
interaction or coordination between the resource server and
authorization server.
5.1. Authenticated Requests
Clients make authenticated token requests using the "Authorization"
request header field as described in Section 5.1.1. Alternatively,
clients MAY include the access token using the HTTP request URI in
the query component as described in Section 5.1.2, or in the HTTP
body when using the "application/x-www-form-urlencoded" content type
as described in Section 5.1.3.
Clients SHOULD only use the request URI or body when the
"Authorization" request header field is not available, and MUST NOT
use more than one method in each request.
5.1.1. The Authorization Request Header Field
The "Authorization" request header field is used by clients to make
authenticated token requests. The client uses the "token" attribute
to include the access token in the request.
For example:
GET /resource HTTP/1.1
Host: server.example.com
Authorization: Token token="vF9dft4qmT"
The "Authorization" header field uses the framework defined by
[RFC2617] as follows:
credentials = "Token" RWS access-token [ CS 1#auth-param ]
access-token = "token" "=" <"> token <">
CS = OWS "," OWS
5.1.2. URI Query Parameter
When including the access token in the HTTP request URI, the client
adds the access token to the request URI query component as defined
by [RFC3986] using the "oauth_token" parameter.
Hammer-Lahav, et al. Expires December 31, 2010 [Page 29]
Internet-Draft OAuth 2.0 June 2010
For example, the client makes the following HTTP request using
transport-layer security:
GET /resource?oauth_token=vF9dft4qmT HTTP/1.1
Host: server.example.com
The HTTP request URI query can include other request-specific
parameters, in which case, the "oauth_token" parameters SHOULD be
appended following the request-specific parameters, properly
separated by an "&" character (ASCII code 38).
For example:
http://example.com/resource?x=y&oauth_token=vF9dft4qmT
5.1.3. Form-Encoded Body Parameter
When including the access token in the HTTP request entity-body, the
client adds the access token to the request body using the
"oauth_token" parameter. The client can use this method only if the
following REQUIRED conditions are met:
o The entity-body is single-part.
o The entity-body follows the encoding requirements of the
"application/x-www-form-urlencoded" content-type as defined by
[W3C.REC-html401-19991224].
o The HTTP request entity-header includes the "Content-Type" header
field set to "application/x-www-form-urlencoded".
o The HTTP request method is "POST", "PUT", or "DELETE".
The entity-body can include other request-specific parameters, in
which case, the "oauth_token" parameters SHOULD be appended following
the request-specific parameters, properly separated by an "&"
character (ASCII code 38).
Hammer-Lahav, et al. Expires December 31, 2010 [Page 30]
Internet-Draft OAuth 2.0 June 2010
For example, the client makes the following HTTP request using
transport-layer security:
POST /resource HTTP/1.1
Host: server.example.com
Content-Type: application/x-www-form-urlencoded
oauth_token=vF9dft4qmT
5.2. The WWW-Authenticate Response Header Field
If the protected resource request contains an invalid access token or
is malformed, the resource server MUST include the HTTP
"WWW-Authenticate" response header field. The "WWW-Authenticate"
header field uses the framework defined by [RFC2617] as follows:
challenge = "Token" RWS token-challenge
token-challenge = realm
[ CS error ]
[ CS error-desc ]
[ CS error-uri ]
[ CS scope ]
[ CS 1#auth-param ]
error = "error" "=" <"> token <">
error-desc = "error-description" "=" quoted-string
error-uri = "error-uri" = <"> URI-Reference <">
scope = ptoken / <"> ptoken *( 1*SP ptoken ) <">
ptoken = 1*ptokenchar
ptokenchar = "!" / "#" / "$" / "%" / "&" / "'" / "("
/ ")" / "*" / "+" / "-" / "." / "/" / DIGIT
/ ":" / "<" / "=" / ">" / "?" / "@" / ALPHA
/ "[" / "]" / "^" / "_" / "`" / "{" / "|"
/ "}" / "~"
For example:
HTTP/1.1 401 Unauthorized
WWW-Authenticate: Token realm='Example Service', error='expired-token'
Hammer-Lahav, et al. Expires December 31, 2010 [Page 31]
Internet-Draft OAuth 2.0 June 2010
The "realm" attribute is used to provide the protected resources
partition as defined by [RFC2617]. [[ add explanation ]]
The "error" attribute is used to provide the client with the reason
why the access request was declined. The parameter values are
described in Section 5.2.1.
The "error-description" attribute provides a human-readable text
containing additional information, used to assist in the
understanding and resolution of the error occurred.
The "error-uri" attribute provides a URI identifying a human-readable
web page with information about the error, used to offer the end-user
with additional information about the error. If the value is not an
absolute URI, it is relative to the URI of the requested protected
resource.
The "scope" attribute is a space-delimited list of scope values
indicating the required scope of the access token for accessing the
requested resource.
5.2.1. Error Codes
The authorization server includes one of the following error codes
with the error response:
invalid-request
The request is missing a required parameter, includes an
unknown parameter or parameter value, repeats the same
parameter, uses more than one method for including an access
token, or is otherwise malformed. The resource server MUST
respond with the HTTP 400 (Bad Request) status code.
invalid-token
The access token provided is invalid. Resource servers SHOULD
use this error code when receiving an expired token which
cannot be refreshed to indicate to the client that a new
authorization is necessary. The resource server MUST respond
with the HTTP 401 (Unauthorized) status code.
expired-token
The access token provided has expired. Resource servers SHOULD
only use this error code when the client is expected to be able
to handle the response and request a new access token using the
refresh token issued with the expired access token. The
resource server MUST respond with the HTTP 401 (Unauthorized)
status code.
Hammer-Lahav, et al. Expires December 31, 2010 [Page 32]
Internet-Draft OAuth 2.0 June 2010
insufficient-scope
The request requires higher privileges than provided by the
access token. The resource server SHOULD respond with the HTTP
403 (Forbidden) status code and MAY include the "scope"
attribute with the scope necessary to access the protected
resource.
[[ Add mechanism for extending error codes ]]
If the request lacks any authentication information (i.e. the client
was unaware authentication is necessary), the resource server SHOULD
not include an error code or other error information.
For example:
HTTP/1.1 401 Unauthorized
WWW-Authenticate: Token realm='Example Service'
6. Extensibility
6.1. Defining New Client Credentials Types
[[ TBD ]]
6.2. Defining New Endpoint Parameters
Applications that wish to define new request or response parameters
for use with the end-user authorization endpoint or the token
endpoint SHALL do so in one of two ways: register them in the
parameters registry (following the procedures in Section 8.1), or use
the "x_" parameter name prefix.
Parameters utilizing the "x_" parameter name prefix MUST be limited
to vendor-specific extensions that are not commonly applicable, and
are specific to the implementation details of the authorization
server where they are used. All other new parameters MUST be
registered, and MUST NOT use the "x_" parameter name prefix.
Parameter names MUST conform to the param-name ABNF, and parameter
values syntax MUST be well-defined (e.g., using ABNF, or a reference
to the syntax of an existing parameter).
param-name = 1*fchar
fchar = "-" / "." / "_" / DIGIT / ALPHA
Hammer-Lahav, et al. Expires December 31, 2010 [Page 33]
Internet-Draft OAuth 2.0 June 2010
6.3. Defining New Header Field Parameters
Applications that wish to define new parameters for use in the OAuth
"Authorization" or "WWW-Authenticate" header fields MUST register
them in the parameters registry, following the procedures in
Section 8.1.
Parameter names MUST conform to the param-name ABNF and MUST NOT
begin with "x_". Parameter values MUST conform to the param-value
ABNF and their syntax MUST be well-defined (e.g., using ABNF, or a
reference to the syntax of an existing parameter).
param-value = ptoken | quoted-string
6.4. Defining New Access Grant Types
The assertion access grant type was designed to allow the
authorization server to accept additional access grants not
specified. Applications that wish to define additional access grant
types can do so by utilizing a new or existing assertion type and
format.
7. Security Considerations
[[ TBD ]]
8. IANA Considerations
8.1. The OAuth Parameters Registry
This document establishes the OAuth parameters registry.
Additional parameters to be use in the end-user authorization
endpoint request, the end-user authorization endpoint response, the
token endpoint request, the token endpoint response, the
"Authorization" header field, or the "WWW-Authenticate" header field,
are registered on the advice of one or more Designated Experts
(appointed by the IESG or their delegate), with a Specification
Required (using terminology from [RFC5226]). However, to allow for
the allocation of values prior to publication, the Designated
Expert(s) may approve registration once they are satisfied that such
a specification will be published.
Registration requests should be sent to the [TBD]@ietf.org mailing
Hammer-Lahav, et al. Expires December 31, 2010 [Page 34]
Internet-Draft OAuth 2.0 June 2010
list for review and comment, with an appropriate subject (e.g.,
"Request for parameter: example"). [[ Note to RFC-EDITOR: The name of
the mailing list should be determined in consultation with the IESG
and IANA. Suggested name: oauth-ext-review. ]]
Before a period of 14 days has passed, the Designated Expert(s) will
either approve or deny the registration request, communicating this
decision both to the review list and to 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@iesg.org mailing list) for resolution.
8.1.1. Registration Template
Parameter name: The name requested (e.g., "example").
Parameter usage location: The location(s) where parameter can be
used. The possible locations are: the end-user authorization
endpoint request, the end-user authorization endpoint response,
the token endpoint request, the token endpoint response, the
"Authorization" header field, or the "WWW-Authenticate" header
field.
Change controller: For standards-track RFCs, state "IETF". For
others, give the name of the responsible party. Other details
(e.g., postal address, e-mail address, home page URI) may also be
included.
Specification document(s): Reference to document that specifies the
parameter, preferably including a URI that can be used to retrieve
a copy of the document. An indication of the relevant sections
may also be included, but is not required.
Related information: Optionally, citations to additional documents
containing further relevant information.
8.1.2. Example
The following is the parameter registration request for the "scope"
parameter as defined in this specification:
Parameter name: scope
Parameter usage location: The end-user authorization endpoint
request, the end-user authorization endpoint response, the token
endpoint request, the token endpoint response, and the
"WWW-Authenticate" header field.
Hammer-Lahav, et al. Expires December 31, 2010 [Page 35]
Internet-Draft OAuth 2.0 June 2010
Change controller: IETF
Specification document(s): [[ this document ]]
Related information: None
Appendix A. Examples
[[ TBD ]]
Appendix B. Contributors
The following people contributed to preliminary versions of this
document: Blaine Cook (BT), Brian Eaton (Google), Yaron Goland
(Microsoft), Brent Goldman (Facebook), Raffi Krikorian (Twitter),
Luke Shepard (Facebook), and Allen Tom (Yahoo!). The content and
concepts within are a product of the OAuth community, WRAP community,
and the OAuth Working Group.
The OAuth Working Group has dozens of very active contributors who
proposed ideas and wording for this document, including: [[ If your
name is missing or you think someone should be added here, please
send Eran a note - don't be shy ]]
Michael Adams, Andrew Arnott, Dirk Balfanz, Brian Campbell, Leah
Culver, Brian Ellin, Igor Faynberg, George Fletcher, Evan Gilbert,
Justin Hart, John Kemp, Chasen Le Hara, Torsten Lodderstedt, Eve
Maler, James Manger, Laurence Miao, Chuck Mortimore, Justin Richer,
Peter Saint-Andre, Nat Sakimura, Rob Sayre, Marius Scurtescu, Justin
Smith, Jeremy Suriel, and Franklin Tse.
Appendix C. Acknowledgements
[[ Add OAuth 1.0a authors + WG contributors ]]
Appendix D. Document History
[[ to be removed by RFC editor before publication as an RFC ]]
-09
o Fixed typos, editorial changes.
Hammer-Lahav, et al. Expires December 31, 2010 [Page 36]
Internet-Draft OAuth 2.0 June 2010
o Added token expiration example.
o Added scope parameter to end-user authorization endpoint response.
o Added note about parameters with empty values (same as omitted).
o Changed parameter values to use '-' instead of '_'. Parameter
names still use '_'.
o Changed authorization endpoint client type to response type with
values: code, token, and both.
o Complete cleanup of error codes. Added support for error
description and URI.
o Add initial extensibility support.
-08
o Renamed verification code to authorization code.
o Revised terminology, structured section, added new terms.
o Changed flows to profiles and moved to introduction.
o Added support for access token rescoping.
o Cleaned up client credentials section.
o New introduction overview.
o Added error code for invalid username and password, and renamed
error code to be more consistent.
o Added access grant type parameter to token endpoint.
-07
o Major rewrite of entire document structure.
o Removed device profile.
o Added verification code support to user-agent flow.
o Removed multiple formats support, leaving JSON as the only format.
o Changed assertion "assertion_format" parameter to
"assertion_type".
Hammer-Lahav, et al. Expires December 31, 2010 [Page 37]
Internet-Draft OAuth 2.0 June 2010
o Removed "type" parameter from token endpoint.
-06
o Editorial changes, corrections, clarifications, etc.
o Removed conformance section.
o Moved authors section to contributors appendix.
o Added section on native applications.
o Changed error response to use the requested format. Added support
for HTTP "Accept" header.
o Flipped the order of the web server and user-agent flows.
o Renamed assertion flow "format" parameter name to
"assertion_format" to resolve conflict.
o Removed the term identifier from token definitions. Added a
cryptographic token definition.
o Added figure titles.
o Added server response 401 when client tried to authenticate using
multiple credentials.
o Clarified support for TLS alternatives, and added requirement for
TLS 1.2 support for token endpoint.
o Removed all signature and cryptography.
o Removed all discovery.
o Updated HTML4 reference.
-05
o Corrected device example.
o Added client credentials parameters to the assertion flow as
OPTIONAL.
o Added the ability to send client credentials using an HTTP
authentication scheme.
Hammer-Lahav, et al. Expires December 31, 2010 [Page 38]
Internet-Draft OAuth 2.0 June 2010
o Initial text for the "WWW-Authenticate" header (also added scope
support).
o Change authorization endpoint to end-user endpoint.
o In the device flow, change the "user_uri" parameter to
"verification_uri" to avoid confusion with the end-user endpoint.
o Add "format" request parameter and support for XML and form-
encoded responses.
-04
o Changed all token endpoints to use "POST"
o Clarified the authorization server's ability to issue a new
refresh token when refreshing a token.
o Changed the flow categories to clarify the autonomous group.
o Changed client credentials language not to always be server-
issued.
o Added a "scope" response parameter.
o Fixed typos.
o Fixed broken document structure.
-03
o Fixed typo in JSON error examples.
o Fixed general typos.
o Moved all flows sections up one level.
-02
o Removed restriction on "redirect_uri" including a query.
o Added "scope" parameter.
o Initial proposal for a JSON-based token response format.
-01
Hammer-Lahav, et al. Expires December 31, 2010 [Page 39]
Internet-Draft OAuth 2.0 June 2010
o Editorial changes based on feedback from Brian Eaton, Bill Keenan,
and Chuck Mortimore.
o Changed device flow "type" parameter values and switch to use only
the token endpoint.
-00
o Initial draft based on a combination of WRAP and OAuth 1.0a.
9. References
9.1. Normative References
[I-D.ietf-httpbis-p1-messaging]
Fielding, R., Gettys, J., Mogul, J., Nielsen, H.,
Masinter, L., Leach, P., Berners-Lee, T., and J. Reschke,
"HTTP/1.1, part 1: URIs, Connections, and Message
Parsing", draft-ietf-httpbis-p1-messaging-09 (work in
progress), March 2010.
[NIST FIPS-180-3]
National Institute of Standards and Technology, "Secure
Hash Standard (SHS). FIPS PUB 180-3, October 2008".
[RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part One: Format of Internet Message
Bodies", RFC 2045, November 1996.
[RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
Hashing for Message Authentication", RFC 2104,
February 1997.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[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.
[RFC2617] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S.,
Leach, P., Luotonen, A., and L. Stewart, "HTTP
Authentication: Basic and Digest Access Authentication",
RFC 2617, June 1999.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.
Hammer-Lahav, et al. Expires December 31, 2010 [Page 40]
Internet-Draft OAuth 2.0 June 2010
[RFC3023] Murata, M., St. Laurent, S., and D. Kohn, "XML Media
Types", RFC 3023, January 2001.
[RFC3447] Jonsson, J. and B. Kaliski, "Public-Key Cryptography
Standards (PKCS) #1: RSA Cryptography Specifications
Version 2.1", RFC 3447, February 2003.
[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, RFC 3629, November 2003.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, January 2005.
[RFC4627] Crockford, D., "The application/json Media Type for
JavaScript Object Notation (JSON)", RFC 4627, July 2006.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008.
[W3C.REC-html401-19991224]
Hors, A., Jacobs, I., and D. Raggett, "HTML 4.01
Specification", World Wide Web Consortium
Recommendation REC-html401-19991224, December 1999,
<http://www.w3.org/TR/1999/REC-html401-19991224>.
9.2. Informative References
[I-D.hammer-oauth]
Hammer-Lahav, E., "The OAuth 1.0 Protocol",
draft-hammer-oauth-10 (work in progress), February 2010.
[I-D.hardt-oauth]
Hardt, D., Tom, A., Eaton, B., and Y. Goland, "OAuth Web
Resource Authorization Profiles", draft-hardt-oauth-01
(work in progress), January 2010.
[OASIS.saml-core-2.0-os]
Cantor, S., Kemp, J., Philpott, R., and E. Maler,
"Assertions and Protocol for the OASIS Security Assertion
Markup Language (SAML) V2.0", OASIS Standard saml-core-
2.0-os, March 2005.
Hammer-Lahav, et al. Expires December 31, 2010 [Page 41]
Internet-Draft OAuth 2.0 June 2010
Authors' Addresses
Eran Hammer-Lahav (editor)
Yahoo!
Email: eran@hueniverse.com
URI: http://hueniverse.com
David Recordon
Facebook
Email: davidrecordon@facebook.com
URI: http://www.davidrecordon.com/
Dick Hardt
Microsoft
Email: dick.hardt@gmail.com
URI: http://dickhardt.org/
Hammer-Lahav, et al. Expires December 31, 2010 [Page 42]
Html markup produced by rfcmarkup 1.129d, available from
https://tools.ietf.org/tools/rfcmarkup/