Internet DRAFT - draft-sakimura-oauth-requrl
draft-sakimura-oauth-requrl
Internet Engineering Task Force N. Sakimura, Ed.
Internet-Draft Nomura Research Institute
Intended status: Standards Track J. Bradley
Expires: January 5, 2015 Ping Identity
July 4, 2014
Request by JWS ver.1.0 for OAuth 2.0
draft-sakimura-oauth-requrl-05
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_uri" parameter that points
to the JWT, allowing the request to be optionally signed and
encrypted.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Request Object . . . . . . . . . . . . . . . . . . . . . 3
2.2. Request Object URI . . . . . . . . . . . . . . . . . . . 3
3. Request Object . . . . . . . . . . . . . . . . . . . . . . . 4
4. Request Object URI . . . . . . . . . . . . . . . . . . . . . 5
5. Authorization Request . . . . . . . . . . . . . . . . . . . . 6
6. Authorization Server Response . . . . . . . . . . . . . . . . 7
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . 7
8. Security Considerations . . . . . . . . . . . . . . . . . . . 7
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
10.1. Normative References . . . . . . . . . . . . . . . . . . 8
10.2. Informative References . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
The parameters "request" and "request_uri" 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 does not suport long
URLs: It is entirely possible that some extensions may extend the
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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 Object 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_uri" 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.
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
For the purposes of this specification, the following terms and
definitions apply.
2.1. Request Object
JWT [JWT] that holds OAuth 2.0 authorization requests as JSON object
in its body
2.2. Request Object URI
absolute URI from which the Request Object (Section 2.1) can be
obtained
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3. Request Object
A Request Object (Section 2.1) is used to provide authorization
request parameters for OAuth 2.0 authorization request. It contains
OAuth 2.0 [RFC6749] authorization request parameters including
extension parameters. It is a JSON Web Signature (JWS) [JWS] signed
JWT [JWT] . The parameters are included as the top level members of
JSON [RFC4627]. Parameter names and string values MUST be included
as JSON strings. Numerical values MUST be included as JSON numbers.
It MAY include any extension parameters. This JSON [RFC4627]
constitues the body of the [JWT].
The 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 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.
REQUIRED OAuth 2.0 Authorization Request parameters that are not
included in the Request Object MUST be sent as a query parameter. If
a required parameter is not present in neither the query parameter or
the Request Object, it forms a malformed request.
If the parameter exists both in the query string and the
Authorization Request Object, they MUST exactly match.
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:
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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. Request Object URI
Instead of sending the Request Object in a OAuth 2.0 authorization
request directly, this specification allows it to be obtained from
the Request Object URI. Using this method has an advantage of
reducing the request size, enabling the caching of the Request
Object, and generally not requiring integrity protection through a
cryptographic operation on the Request Object if the channel itself
is protected.
The Request Object URI is sent as a part of the OAuth Authorization
Request as the value for the parameter called "request_uri". How the
Request Object is registered at Request Object URI is out of scope of
this specification, but it MUST be done in a protected channel.
NOTE: the Request Object MAY be registered at the Authorization
Server at the client registration time.
When the Authorization Server obtains the Request Object from Request
Object URI, it MUST do so over a protected channel. If it is
obtained from a remote server, it SHOULD use either HTTP over TLS 1.2
as defined in RFC5246 [RFC5246] AND/OR [JWS] with the algorithm
considered appropriate at the time.
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When sending the request by "request_uri", the client MAY provide the
sha256 hash as defined in FIPS180-2 [FIPS180-2]of the Request Object
as the fragment to it to assist the cache utilization decision of the
Authorization Server.
5. Authorization Request
The client constructs the authorization request URI by adding the
following 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 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 Request Object (Section 3) that holds
authorization request parameters stated in the section 4 of OAuth
2.0 [RFC6749].
state RECOMMENDED. OAuth 2.0 [RFC6749] state.
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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6. 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:
invalid_request_uri The provided request_uri was not available.
invalid_request_format The Request Object format was invalid.
invalid_request_params The parameter set provided in the Request
Object was invalid.
7. IANA Considerations
This document registers following error strings to the OAuth Error
Registry.
invalid_request_uri The provided request_uri was not available.
invalid_request_format The Request Object format was invalid.
invalid_request_params The parameter set provided in the Request
Object was invalid.
8. Security Considerations
In addition to the all the security considerations discussed in OAuth
2.0 [RFC6819], the following security considerations SHOULD be taken
into account.
When sending the authorization request object through "request"
parameter, it SHOULD be signed with then considered appropriate
algorithm using[JWS]. The "alg=none" SHOULD NOT be used in such a
case.
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
recommended.
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9. 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).
10. References
10.1. 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.
[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.
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[RFC6749] Hardt, D., "The OAuth 2.0 Authorization Framework", RFC
6749, October 2012.
[RFC6819] Lodderstedt, T., McGloin, M., and P. Hunt, "OAuth 2.0
Threat Model and Security Considerations", RFC 6819,
January 2013.
10.2. Informative References
[openid_ab]
openid-specs-ab@openid.net, , "OpenID Connect Core 1.0",
November 2013.
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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