One document matched: draft-ietf-oauth-v2-bearer-00.xml
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<rfc category='std' ipr='trust200902' docName='draft-ietf-oauth-v2-bearer-00'>
<?rfc strict='yes' ?>
<?rfc toc='yes' ?>
<?rfc tocdepth='3' ?>
<?rfc symrefs='yes' ?>
<?rfc sortrefs='yes' ?>
<?rfc compact='yes' ?>
<?rfc subcompact='no' ?>
<front>
<title abbrev='OAuth 2.0 Bearer Tokens'>The OAuth 2.0 Protocol: Bearer Tokens</title>
<author fullname='Michael B. Jones' surname='Jones' initials='M.B.' role='editor'>
<organization>Microsoft</organization>
<address>
<email>mbj@microsoft.com</email>
<uri>http://self-issued.info/</uri>
</address>
</author>
<author fullname='Eran Hammer-Lahav' surname='Hammer-Lahav' initials='E'>
<organization>Yahoo!</organization>
<address>
<email>eran@hueniverse.com</email>
<uri>http://hueniverse.com</uri>
</address>
</author>
<author fullname='Dick Hardt' surname='Hardt' initials='D'>
<organization>independent</organization>
<address>
<email>dick.hardt@gmail.com</email>
<uri>http://dickhardt.org/</uri>
</address>
</author>
<author fullname='David Recordon' surname='Recordon' initials='D'>
<organization>Facebook</organization>
<address>
<email>davidrecordon@facebook.com</email>
<uri>http://www.davidrecordon.com/</uri>
</address>
</author>
<date year="2010" month="November" day="30" />
<abstract>
<t>
This specification describes how to use bearer tokens when accessing OAuth 2.0
protected resources.
</t>
</abstract>
</front>
<middle>
<section title='Introduction'>
<t>
OAuth enables clients to access protected resources by
obtaining an access token (a string that denotes a specific
scope, duration, and other attributes), rather than using the
resource owner's credentials.
</t>
<t>
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. This specification describes how to make protected resource
requests by treating an OAuth access token as a bearer token.
</t>
<t>
This specification defines the use of OAuth over <xref target='RFC2616'>HTTP</xref>
(or HTTP over TLS as defined by <xref target='RFC2818' />). Other specifications may
extend it for use with other transport protocols.
</t>
<section title='Notational Conventions'>
<t>
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 <xref target='RFC2119' />.
</t>
<t>
This document uses the Augmented Backus-Naur Form (ABNF) notation of
<xref target='I-D.ietf-httpbis-p1-messaging' />. Additionally, the following rules are
included from <xref target='RFC2617' />: realm, auth-param; from
<xref target='RFC3986' />: URI-Reference; and from
<xref target='I-D.ietf-httpbis-p1-messaging' />: OWS, RWS, and quoted-string.
</t>
<t>
Unless otherwise noted, all the protocol parameter names and values are case sensitive.
</t>
</section>
<section title='Terminology'>
<t>
All terms are as defined in <xref target="OAuth2">The OAuth 2.0 Protocol</xref>.
</t>
</section>
<section title='Overview'>
<t>
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 (access grant) 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.
</t>
<t>
The access token provides an abstraction layer, replacing different authorization
constructs (e.g. username and password, assertion) for a single token understood by the
resource server. This abstraction enables issuing access tokens valid for a short time
period, as well as removing the resource server's need to understand a wide range of
authentication schemes.
</t>
<figure title='Abstract Protocol Flow' anchor='Figure 1'>
<artwork>
<![CDATA[+--------+ +---------------+
| |--(A)- Authorization Request ->| Resource |
| | | Owner |
| |<-(B)----- Access Grant -------| |
| | +---------------+
| |
| | Access Grant & +---------------+
| |--(C)--- Client Credentials -->| Authorization |
| Client | | Server |
| |<-(D)----- Access Token -------| |
| | +---------------+
| |
| | +---------------+
| |--(E)----- Access Token ------>| Resource |
| | | Server |
| |<-(F)--- Protected Resource ---| |
+--------+ +---------------+]]>
</artwork>
</figure>
<t>
The abstract flow illustrated in <xref target='Figure 1' /> describes the overall
OAuth 2.0 protocol architecture. The following steps are specified within this
document:
<list>
<t>
E) The client makes a protected resource request to the resource server by presenting
the access token.
</t>
<t>
F) The resource server validates the access token, and if valid, serves the request.
</t>
</list>
</t>
</section>
</section>
<section title='Authenticated Requests'>
<t>
Clients make authenticated token requests using the
<spanx style='verb'>Authorization</spanx> request header field. Resource servers MUST
accept authenticated requests using the <spanx style='verb'>OAuth</spanx> HTTP
authentication scheme as described in <xref target='authz-header' />, and MAY support
additional methods.
</t>
<t>
Alternatively, clients MAY attempt to include the access token using the HTTP request
URI in the query component as described in <xref target='query-param' />, or in the HTTP
body when using the <spanx style='verb'>application/x-www-form-urlencoded</spanx> content
type as described in <xref target='body-param' />. Resource server MAY support these
alternative methods.
</t>
<t>
Clients SHOULD only use the request URI or body when the
<spanx style='verb'>Authorization</spanx> request header field is not available, and MUST
NOT use more than one method in each request.
</t>
<section title='The Authorization Request Header Field' anchor='authz-header'>
<t>
The <spanx style='verb'>Authorization</spanx> request header field is used by clients
to make authenticated token requests. The client uses the
<spanx style='verb'>OAuth</spanx> authentication scheme to include the access token in
the request.
</t>
<figure>
<preamble>
For example:
</preamble>
<artwork>
<![CDATA[GET /resource HTTP/1.1
Host: server.example.com
Authorization: OAuth vF9dft4qmT]]>
</artwork>
</figure>
<t>
The <spanx style='verb'>Authorization</spanx> header field uses the framework defined by
<xref target='RFC2617' /> as follows:
</t>
<figure>
<artwork>
<![CDATA[credentials = "OAuth" RWS access-token [ RWS 1#auth-param ]
access-token = 1*( quoted-char / <"> )
quoted-char = "!" / "#" / "$" / "%" / "&" / "'" / "("
/ ")" / "*" / "+" / "-" / "." / "/" / DIGIT
/ ":" / "<" / "=" / ">" / "?" / "@" / ALPHA
/ "[" / "]" / "^" / "_" / "`" / "{" / "|"
/ "}" / "~" / "\" / "," / ";"]]>
</artwork>
</figure>
<t>
<list>
<t>
NOTE: <xref target='RFC5849' /> defines a different format for the
<spanx style='verb'>OAuth</spanx> authentication scheme. Resource servers can
differentiate between the two protocol versions based on the presence of the
<spanx style='verb'>oauth_signature_method</spanx> which is REQUIRED in the
previous version and is not supported by this specification.
</t>
</list>
</t>
</section>
<section title='URI Query Parameter' anchor='query-param'>
<t>
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 <xref target='RFC3986' /> using
the <spanx style='verb'>oauth_token</spanx> parameter.
</t>
<figure>
<preamble>
For example, the client makes the following HTTP request using transport-layer
security:
</preamble>
<artwork>
<![CDATA[GET /resource?oauth_token=vF9dft4qmT HTTP/1.1
Host: server.example.com]]>
</artwork>
</figure>
<t>
The HTTP request URI query can include other request-specific parameters, in which
case, the <spanx style='verb'>oauth_token</spanx> parameters SHOULD be appended
following the request-specific parameters, properly separated by an
<spanx style='verb'>&</spanx> character (ASCII code 38).
</t>
<figure>
<preamble>
For example:
</preamble>
<artwork>
<![CDATA[http://example.com/resource?x=y&oauth_token=vF9dft4qmT]]>
</artwork>
</figure>
<t>
<list>
<t>
NOTE: The <spanx style='verb'>oauth_token</spanx> parameter is used by the previous
version of the OAuth protocol as described in <xref target='RFC5849' />. Resource
servers can differentiate between the two protocol versions based on the presence
of the <spanx style='verb'>oauth_signature_method</spanx> which is REQUIRED in the
previous version and is not supported by this specification.
</t>
</list>
</t>
</section>
<section title='Form-Encoded Body Parameter' anchor='body-param'>
<t>
When including the access token in the HTTP request entity-body, the client adds the
access token to the request body using the <spanx style='verb'>oauth_token</spanx>
parameter. The client can use this method only if the following REQUIRED conditions are
met:
<list style='symbols'>
<t>
The entity-body is single-part.
</t>
<t>
The entity-body follows the encoding requirements of the
<spanx style='verb'>application/x-www-form-urlencoded</spanx> content-type as
defined by <xref target='W3C.REC-html401-19991224' />.
</t>
<t>
The HTTP request entity-header includes the <spanx style='verb'>Content-Type</spanx>
header field set to <spanx style='verb'>application/x-www-form-urlencoded</spanx>.
</t>
<t>
The HTTP request method is <spanx style='verb'>POST</spanx>,
<spanx style='verb'>PUT</spanx>, or <spanx style='verb'>DELETE</spanx>.
</t>
</list>
</t>
<t>
The entity-body can include other request-specific parameters, in which case, the
<spanx style='verb'>oauth_token</spanx> parameters SHOULD be appended following the
request-specific parameters, properly separated by an <spanx style='verb'>&</spanx>
character (ASCII code 38).
</t>
<figure>
<preamble>
For example, the client makes the following HTTP request using transport-layer
security:
</preamble>
<artwork>
<![CDATA[POST /resource HTTP/1.1
Host: server.example.com
Content-Type: application/x-www-form-urlencoded
oauth_token=vF9dft4qmT]]>
</artwork>
</figure>
<t>
<list>
<t>
NOTE: The <spanx style='verb'>oauth_token</spanx> parameter is used by the previous
version of the OAuth protocol as described in <xref target='RFC5849' />. Resource
servers can differentiate between the two protocol versions based on the presence
of the <spanx style='verb'>oauth_signature_method</spanx> which is REQUIRED in the
previous version and is not supported by this specification.
</t>
</list>
</t>
</section>
<section title='The WWW-Authenticate Response Header Field' anchor='authn-header'>
<t>
If the protected resource request contains an invalid access token or is malformed, the
resource server MUST include the HTTP <spanx style='verb'>WWW-Authenticate</spanx>
response header field. The <spanx style='verb'>WWW-Authenticate</spanx> header field
uses the framework defined by <xref target='RFC2617' /> as follows:
</t>
<figure>
<artwork>
<![CDATA[challenge = "OAuth" 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 = quoted-value /
<"> quoted-value *( 1*SP quoted-value ) <">
quoted-value = 1*quoted-char
CS = OWS "," OWS]]>
</artwork>
</figure>
<figure>
<preamble>
For example:
</preamble>
<artwork>
<![CDATA[HTTP/1.1 401 Unauthorized
WWW-Authenticate: OAuth realm="Example Service",
error="invalid_token",
error_description="The access token expired"]]>
</artwork>
</figure>
<t>
The <spanx style='verb'>realm</spanx> attribute is used to provide the protected
resources partition as defined by <xref target='RFC2617' />. [[ add explanation ]]
</t>
<t>
The <spanx style='verb'>error</spanx> attribute is used to provide the client with the
reason why the access request was declined. The parameter values are described in
<xref target='resource-error-codes' />.
</t>
<t>
The <spanx style='verb'>error_description</spanx> attribute provides a human-readable
text containing additional information, used to assist in the understanding and
resolution of the error occurred.
</t>
<t>
The <spanx style='verb'>error_uri</spanx> 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.
</t>
<t>
The <spanx style='verb'>scope</spanx> attribute is a space-delimited list of scope values
indicating the required scope of the access token for accessing the requested resource.
</t>
</section>
<section title='Error Codes' anchor='resource-error-codes'>
<t>
When a request fails, the resource server responds using the appropriate HTTP status
code (typically, 400, 401, or 403), and includes one of the following error codes in
the response:
<list style='hanging' hangIndent='6'>
<t hangText='invalid_request'>
<vspace />
The request is missing a required parameter, includes an unsupported 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 SHOULD
respond with the HTTP 400 (Bad Request) status code.
</t>
<t hangText='invalid_token'>
<vspace />
The access token provided is expired, revoked, malformed, or invalid for other
reasons. The resource SHOULD respond with the HTTP 401 (Unauthorized) status
code. The client MAY request a new access token and retry the protected resource
request.
</t>
<t hangText='insufficient_scope'>
<vspace />
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 <spanx style='verb'>scope</spanx> attribute with the scope necessary to
access the protected resource.
</t>
</list>
</t>
<t>
[[ Add mechanism for extending error codes ]]
</t>
<t>
If the request lacks any authentication information (i.e. the client was unaware
authentication is necessary or attempted using an unsupported authentication method),
the resource server SHOULD not include an error code or other error information.
</t>
<figure>
<preamble>
For example:
</preamble>
<artwork>
<![CDATA[HTTP/1.1 401 Unauthorized
WWW-Authenticate: OAuth realm="Example Service"]]>
</artwork>
</figure>
</section>
</section>
<section title='Security Considerations'>
<t>
Implementers and deployers must ensure that bearer tokens are
not leaked to unintended parties, as they will be able to use
them to gain access to protected resources. This is the
primary security consideration when using bearer tokens with
OAuth and underlies all the more specific statements that
follow.
</t>
<section title="Validate SSL Certificate Chains">
<t>
The client must validate the TLS certificate chain when
making requests to protected resources. Failing to do so
may enable DNS hijacking attacks to steal the token and gain
unintended access.
</t>
</section>
<section title="Always use TLS (https)">
<t>
Clients must always use TLS (https) when making requests
with bearer tokens. Failing to do so exposes the token to
numerous attacks that could give attackers unintended
access.
</t>
</section>
<section title="Don't store bearer tokens in cookies">
<t>
As cookies are generally sent in the clear, implementations must not store bearer tokens within them.
</t>
</section>
<section title="Issue short-lived bearer tokens">
<t>
Using short-lived (one hour or less) bearer tokens can
reduce the impact of one of them being leaked. The
User-Agent flow should only issue short lived access tokens.
</t>
</section>
</section>
<appendix title='Acknowledgements'>
<t>
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.
</t>
<t>
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 Mike Jones a note - don't be shy ]]
</t>
<t>
Michael Adams, Andrew Arnott, Dirk Balfanz, Brian Campbell, Leah Culver, Bill de hÓra,
Brian Ellin, Igor Faynberg, George Fletcher, Tim Freeman, Evan Gilbert, Justin Hart,
John Kemp, Chasen Le Hara, Michael B. Jones, Torsten Lodderstedt, Eve Maler, James Manger, Laurence Miao,
Chuck Mortimore, Justin Richer, Peter Saint-Andre, Nat Sakimura, Rob Sayre,
Marius Scurtescu, Naitik Shah, Justin Smith, Jeremy Suriel, Christian Stübner, Paul Tarjan,
and Franklin Tse.
</t>
</appendix>
<appendix title='Document History'>
<t>
[[ to be removed by RFC editor before publication as an RFC ]]
</t>
<t>
-00
<list style='symbols'>
<t>
Initial draft based on preliminary version of OAuth 2.0 draft 11.
</t>
</list>
</t>
</appendix>
</middle>
<back>
<references title='Normative References'>
<?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.2119.xml' ?>
<?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.2616.xml' ?>
<?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.2617.xml' ?>
<?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.2818.xml' ?>
<?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.3986.xml' ?>
<?rfc include='http://xml.resource.org/public/rfc/bibxml/reference.RFC.5849.xml' ?>
<?rfc include='http://xml.resource.org/public/rfc/bibxml4/reference.W3C.REC-html401-19991224.xml' ?>
<?rfc include='http://xml.resource.org/public/rfc/bibxml3/reference.I-D.draft-ietf-httpbis-p1-messaging-09.xml'?>
<reference anchor="OAuth2"> <!--TBD What is the correct way to reference the framework specification?-->
<front>
<title>The OAuth 2.0 Protocol</title>
<author fullname='Eran Hammer-Lahav' surname='Hammer-Lahav' initials='E' role='editor'>
<organization>Yahoo!</organization>
<address>
<email>eran@hueniverse.com</email>
<uri>http://hueniverse.com</uri>
</address>
</author>
<author fullname='David Recordon' surname='Recordon' initials='D'>
<organization>Facebook</organization>
<address>
<email>davidrecordon@facebook.com</email>
<uri>http://www.davidrecordon.com/</uri>
</address>
</author>
<author fullname='Dick Hardt' surname='Hardt' initials='D'>
<organization>independent</organization>
<address>
<email>dick.hardt@gmail.com</email>
<uri>http://dickhardt.org/</uri>
</address>
</author>
<date year='2010' />
</front>
</reference>
</references>
</back>
</rfc>
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