Internet Engineering Task Force N. Sakimura, Ed.
Internet-Draft Nomura Research Institute
Intended status: Standards Track J. Bradley
Expires: May 10, 2013 Ping Identity
November 6, 2012
Request by JWS ver.1.0 for OAuth 2.0
draft-sakimura-oauth-requrl-03
Abstract
The authorization request in OAuth 2.0 utilizes query parameter
serizalization. This specification defines the authorization request
using JWT serialization. The request is sent thorugh 'request'
parameter or by reference through 'request_url' that points to the
JWT, allowing the request to be optionally signed and encrypted.
Status of this Memo
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This Internet-Draft will expire on May 10, 2013.
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described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Authorization Request Object . . . . . . . . . . . . . . . . . 4
4. Authorization Request . . . . . . . . . . . . . . . . . . . . . 5
5. Authorization Server Response . . . . . . . . . . . . . . . . . 7
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
7. Security Considerations . . . . . . . . . . . . . . . . . . . . 7
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8
9.1. Normative References . . . . . . . . . . . . . . . . . . . 8
9.2. Informative References . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9
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1. Introduction
The parameters 'request' and 'request_url' are introduced as
additional authorization request parameters for the OAuth 2.0
[RFC6749] flows. The 'request' parameter is a JSON Web Token (JWT)
[JWT] whose body holds the JSON encoded OAuth 2.0 authorization
request parameters. The [JWT] can be passed to the authorization
endpoint by reference, in which case the parameter 'request_uri' is
used instead of the 'request'.
Using [JWT] as the request encoding instead of query parameters has
several advantages:
1. The request may be signed so that integrity check may be
implemented. If a suitable algorithm is used for the signing,
then non-repudiation property may be obtained in addition.
2. The request may be encrypted so that end-to-end confidentiality
may be obtained even if in the case TLS connection is terminated
at a gateway or a similar device.
There are a few cases that request by reference is useful such as:
1. When it is detected that the User Agent dose't suport long URLs -
It is entirely possible that some extensions may extend the URL.
For example, the client might want to send a public key with the
request.
2. Static signature: The client may make a signed request file and
put it on the client. This may just be done by a client utility
or other process, so that the private key does not have to reside
on the client, simplifying programming.
3. When the server wants the requests to be cacheable - The
request_uri may include a sha256 hash of the file, as defined in
FIPS180-2 [FIPS180-2], the server knows if the file has changed
without fetching it, so it does not have to re-fetch a same file,
which is a win as well.
4. When the client wants to simplify the implementation without
compromising the security. If the request parameters go through
the Browser, they may be tampered in the browser even if TLS was
used. This implies we need to have signature on the request as
well. However, if HTTPS request_url was used, it is not going to
be tampered, thus we now do not have to sign the request. This
simplifies the implementation.
This capability is in use by OpenID Connect.
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1.1. Requirements Language
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 RFC 2119 [RFC2119].
2. Terminology
Following parameters are defined as a request and response parameter.
request object A [JWT] that holds OAuth 2.0 authorization requests
as JSON object in its body. It MAY include all the potential
variables including extension and non-oauth variables. Request
object can optionally be digitally signed or signed and encrypted.
To sign, [JWS] is used. To encrypt, [JWE] is used.
request_uri The absolute URL from which the request object is
obtained.
Request File This is a physical or logical file that the
'request_url' points to.
3. Authorization Request Object
The Authorization Request object is used to provide authorization
request parameters. It contains OAuth 2.0 authorization request
parameters including extension parameters. It is a JSON Web
Signature (JWS) [JWS] signed JWT [JWT] that has the JSON object that
holds the OAuth 2.0 authorization request parameters. The parameters
are included as the top level members of JSON [RFC4627]. Parameter
names and string values are included as JSON strings. Numerical
values are included as JSON numbers. It MAY include any extension
parameters. This JSON [RFC4627] constitues the body of the [JWT].
The Authorization Request Object MAY be signed or unsigned
(plaintext). When it is plaintext, this is indicated by use of the
"none" algorithm [JWA] in the JWS header. If signed, the
Authorization Request Object SHOULD contain the Claims "iss" (issuer)
and "aud" (audience) as members, with their semantics being the same
as defined in the JWT [JWT] specification.
The Authorization Request Object MAY also be encrypted using JWE
[JWE] after signing, with nesting performed in the same manner as
specified for JWTs [JWT]. The Authorization Request Object MAY
alternatively be sent by reference using "request_uri" parameter.
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OAuth 2.0 Authorization Request parameters that are not included in
the Authorization Request Object MAY be sent as a query parameter.
If the parameter exists both in the query string and the
Authorization Request Object, they MUST exactly match.
If a required parameter is not present in neither the query parameter
or the Authorization Request Object, it forms a malformed request.
Following is the example of the JSON which consitutes the body of the
[JWT].
{
"redirect_url":"https://example.com/rp/endpoint_url",
"cliend_id":"http://example.com/rp/"
}
The following is a non-normative example of a [JWT] encoded
authorization request object. It includes extension variables such
as "nonce", "userinfo", and "id_token". Note that the line wraps
within the values are for display purpose only:
JWT algorithm = HS256
HMAC HASH Key = 'aaa'
JSON Encoded Header = "{"alg":"HS256","typ":"JWT"}"
JSON Encoded Payload = "{"response_type":"code id_token",
"client_id":"s6BhdRkqt3",
"redirect_uri":"https://client.example.com/cb",
"scope":"openid profile",
"state":"af0ifjsldkj",
"nonce":"n-0S6_WzA2Mj",
"userinfo":{"claims":{"name":null,"nickname":{"optional":true},
"email":null,"verified":null,
"picture":{"optional":true}},"format":"signed"},
"id_token":{"max_age":86400,"iso29115":"2"}}"
JWT = eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJyZXNwb25zZV90eXBlIjoiY29kZ
SBpZF90b2tlbiIsImNsaWVudF9pZCI6InM2QmhkUmtxdDMiLCJyZWRpcmVjdF91cmkiO
iJodHRwczpcL1wvY2xpZW50LmV4YW1wbGUuY29tXC9jYiIsInNjb3BlIjoib3BlbmlkI
HByb2ZpbGUiLCJzdGF0ZSI6ImFmMGlmanNsZGtqIiwidXNlcmluZm8iOnsiY2xhaW1zI
jp7Im5hbWUiOm51bGwsIm5pY2tuYW1lIjp7Im9wdGlvbmFsIjp0cnVlfSwiZW1haWwiO
m51bGwsInZlcmlmaWVkIjpudWxsLCJwaWN0dXJlIjp7Im9wdGlvbmFsIjp0cnVlfX0sI
mZvcm1hdCI6InNpZ25lZCJ9LCJpZF90b2tlbiI6eyJtYXhfYWdlIjo4NjQwMCwiaXNvM
jkxMTUiOiIyIn19.2OiqRgrbrHkA1FZ5p_7bc_RSdTbH-wo_Agk-ZRpD3wY
4. Authorization Request
The client constructs the request URI by adding the following
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parameters to the query component of the authorization endpoint URI
using the "application/x-www-form-urlencoded" format:
request REQUIRED unless "request_uri" is specified. The
authorization request object (Section 3) that holds authorization
request parameters stated in the section 4 of OAuth 2.0 [RFC6749].
request_uri REQUIRED unless "request" is specified. The absolute
URL that points to the authorization request object (Section 3)
that holds authorization request parameters stated in the section
4 of OAuth 2.0 [RFC6749]. When sending the request by
"request_uri", the client MAY provide the sha256 hash as defined
in FIPS180-2 [FIPS180-2]of the Request File as the fragment to it
to assist the cache utilization decision of the Authorization
Server.
state RECOMMENDED. 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 parameter SHOULD be used for preventing cross-site
request forgery as described in Section 10.12. of OAuth 2.0
[RFC6749]
The client directs the resource owner to the constructed URI using an
HTTP redirection response, or by other means available to it via the
user-agent.
For example, the client directs the end-user's user-agent to make the
following HTTPS request (line breaks are for display purposes only):
GET /authorize?request_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb HTTP/1.1
Host: server.example.com
The autorization request object MAY be signed AND/OR encrypted.
Upon receipt of "request_uri" in the request, the authorization
server MUST send a GET request to the "request_uri" to retrieve the
authorization request object unless it is already cached at the
Authorization Server.
If the response was signed AND/OR encrypted, it has to be decoded
accordingly before being processed.
Then, the Authorization Server MUST reconstruct the complete client
request from the original HTTP request and the content of the request
object. Then, the process continues as described in Section 3 of
OAuth 2.0 [RFC6749] .
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5. Authorization Server Response
Authorization Server Response is created and sent to the client as in
Section 4 of OAuth 2.0 [RFC6749] .
In addition, this document defines additional 'error' values as
follows:
o "invalid_request_uri" - The provided request_uri was not
available.
o "invalid_request_format" - The Request Object format was invalid.
o "invalid_request_params" - The parameter set provided in the
Request Object was invalid.
6. IANA Considerations
This document registers following error strings to the OAuth Error
Registry.
o "invalid_request_uri" - The provided request_uri was not
available.
o "invalid_request_format" - The Request Object format was invalid.
o "invalid_request_params" - The parameter set provided in the
Request Object was invalid.
7. Security Considerations
In addition to the all the security considerations discussed in OAuth
2.0 [RFC6749], the following security considerations SHOULD be taken
into account.
When sending the authorization request object through "request"
parameter, it SHOULD be signed with [JWS].
When obtaining the Request FIle, the Authorization Server SHOULD use
either HTTP over TLS 1.2 as defined in RFC5246 [RFC5246] AND/OR
[JWS].
If the request object contains personally identifiable or sensitive
information, the "request_uri" MUST be of one-time use and MUST have
large enough entropy deemed necessary with applicable security
policy. For higher security requirement, using [JWE] is strongly
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recommended.
[[ToDo]]
8. Acknowledgements
Following people contributed to creating this document through the
OpenID Connect 1.0 [openid_ab] .
Breno de Medeiros (Google), Hideki Nara (TACT), John Bradley (Ping
Identity) <author>, Nat Sakimura (NRI) <author/editor>, Ryo Itou
(Yahoo! Japan), George Fletcher (AOL), Justin Richer (Mitre), Edmund
Jay (MGI1), (add yourself).
In addition following people contributed to this and previous
versions through The OAuth Working Group.
David Recordon (Facebook), Luke Shepard (Facebook), James H. Manger
(Telstra), Marius Scurtescu (Google), John Panzer (Google), Dirk
Balfanz (Google), (add yourself).
9. References
9.1. Normative References
[FIPS180-2]
U.S. Department of Commerce and National Institute of
Standards and Technology, "Secure Hash Signature
Standard", FIPS 180-2, August 2002.
Defines Secure Hash Algorithm 256 (SHA256)
[JWA] Jones, M., "JSON Web Algorithms (JWA)", March 2011.
[JWE] Jones, M., "JSON Web Encryption (JWE)", March 2011.
[JWS] Jones, M., Balfanz, D., Bradley, J., Goland, Y., Panzer,
J., Sakimura, N., and P. Tarjan, "JSON Web Signature
(JWS)", April 2011.
[JWT] Jones, M., Balfanz, D., Bradley, J., Goland, Y., Panzer,
J., Sakimura, N., and P. Tarjan, "JSON Web Token",
July 2011.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
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[RFC4627] Crockford, D., "The application/json Media Type for
JavaScript Object Notation (JSON)", RFC 4627, July 2006.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, August 2008.
[RFC6749] Hardt, D., "The OAuth 2.0 Authorization Framework",
RFC 6749, October 2012.
9.2. Informative References
[openid_ab]
openid-specs-ab@openid.net, "OpenID Connect 1.0",
October 2011.
Authors' Addresses
Nat Sakimura (editor)
Nomura Research Institute
1-6-5 Marunouchi, Marunouchi Kitaguchi Bldg.
Chiyoda-ku, Tokyo 100-0005
Japan
Phone: +81-3-5533-2111
Email: n-sakimura@nri.co.jp
John Bradley
Ping Identity
Email: ve7jtb@ve7jtb.com
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