Re: [OAUTH-WG] Scope parameter values for "authorization_code" and "client_credentials" based access tokens

[Marty Burns <[e-mail]>]

Don's email describes why we changed from space to comma for separator
between Scopes. The reason we don't use space inside a scope string is that
we wanted the OAuth layer to treat a scope string as an atomic thing,
rather than a list of independent parameters. The use of space delimits
independent scopes in OAuth.  So we wanted to keep each Scope string as a
separate "scope-token" (see definition below).



Each data custodian will support a small finite set of permutations of the
Scope string (often only one). It is the set that describes the scope.



BTW, here is the full description of the Scope parameter from RFC 6749:

      *3.3*<file:///C:\_Project\NIST\NISTGreenButton\Work\GreenButton\GreenButtonCMDWorkshop\references\rfc6749.htm#section-3.3>*.
Access Token Scope*

   The authorization and token endpoints allow the client to specify the

   scope of the access request using the "scope" request parameter.  In

   turn, the authorization server uses the "scope" response parameter to

   inform the client of the scope of the access token issued.



   The value of the scope parameter is expressed as a list of space-

   delimited, case-sensitive strings.  The strings are 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.



     scope       = scope-token *( SP scope-token )

     scope-token = 1*( %x21 / %x23-5B / %x5D-7E )



   The authorization server MAY fully or partially ignore the scope

   requested by the client, based on the authorization server policy or

   the resource owner's instructions.  If the issued access token scope

   is different from the one requested by the client, the authorization

   server MUST include the "scope" response parameter to inform the

   client of the actual scope granted.



   If the client omits the scope parameter when requesting

   authorization, the authorization server MUST either process the

   request using a pre-defined default value or fail the request

   indicating an invalid scope.  The authorization server SHOULD

   document its scope requirements and default value (if defined).





HTH,

Marty



*From:* Teeter, John [mailto:[e-mail]]
*Sent:* Monday, February 17, 2014 8:41 AM
*To:* Marty Burns; Donald Coffin; Bill Mills; [e-mail]
*Cc:* greenbutton-dev
*Subject:* Re: [OAUTH-WG] Scope parameter values for "authorization_code"
and "client_credentials" based access tokens



Remind be again please why we still do not use "space" as a separator in
our Scope?  Seem so me the appropriate scope for the example below should
be:



  "FB=4_*5_*15 IntervalDuration=900 BlockDuration=monthly HistoryLength=13
BR=04"



If we do use "space' as a separator, I can understand the way that the BR
value can be mixed in to the non BR scopes.



So why do we not use the "space" separator?



jt



*From: *Marty Burns <[e-mail]>
*Date: *Sunday, February 16, 2014 8:34 PM
*To: *Donald Coffin <[e-mail]>, Bill Mills <
[e-mail]>, "[e-mail]" <[e-mail]>
*Cc: *greenbutton-dev <[e-mail]>
*Subject: *RE: [OAUTH-WG] Scope parameter values for "authorization_code"
and "client_credentials" based access tokens



Don,



Good comment. One point - the authorizations covered by BulkId=04 would
have Scopes of:


FB=4_5_15;IntervalDuration=900;BlockDuration=monthly;HistoryLength=13;BR=04

Marty





*From:*[e-mail] [mailto:
[e-mail]] *On Behalf Of *Donald Coffin
*Sent:* Sunday, February 16, 2014 8:14 PM
*To:* 'Bill Mills'; [e-mail]
*Cc:* 'greenbutton-dev'
*Subject:* RE: [OAUTH-WG] Scope parameter values for "authorization_code"
and "client_credentials" based access tokens



Bill,



Thanks for your reply, but I'm not sure you fully understand the situation
I am attempting to resolve.



For example, does an access token obtained via the "client_credentials"
request with the following SCOPE parameter:

                        BulkID=04

allow a client to ask for resources when the individual access token
contained the following SCOPE parameter:


FB=4_5_15;IntervalDuration=900;BlockDuration=monthly;HistoryLength=13



The question is what individual access token authorization should be
covered by the "client_credentials" based access token?



Best regards,

Don

Donald F. Coffin

Founder/CTO



REMI Networks

22751 El Prado Suite 6216

Rancho Santa Margarita, CA  92688-3836



Phone:      [phone]

Email:       [e-mail]



*From:* Bill Mills [mailto:[e-mail] <[e-mail]>]
*Sent:* Saturday, February 15, 2014 8:30 PM
*To:* Donald Coffin; [e-mail]
*Cc:* greenbutton-dev
*Subject:* Re: [OAUTH-WG] Scope parameter values for "authorization_code"
and "client_credentials" based access tokens



To tokens themselves don't differ based on how they are obtained unless you
want them to.  No requirement to match scope to the client ID either, but
again it's up to you.



You do want to get this right.  The challenge here is that your resource
servers have to get updated to support new scopes.  If they support
auto-updates then it's not quite as big a deal but it's still non-trivial.



-bill







On Saturday, February 15, 2014 7:01 PM, Donald Coffin <
[e-mail]> wrote:

I would like to get the views and comments of the OAuth 2.0 IETF WG on the
following design and implementation question:



I have an application that supports both "authorization_code" and
"client_credentials" based access tokens.  The application allows a client
to obtain data on a nightly basis for resource owners who have granted the
application access to their data.  The client application retrieves energy
usage information and can potentially need to retrieve data from a few
accounts to several million accounts.  In order to eliminate the need for
the client application to request the data from the resource server one
account at a time, the client application has been designed to support
"client_credentials" based access tokens.  Per [RFC 6749 Section 4.4 -
"Client Credentials Grant"] The use of the "client_credentials" based
access token will allow the client application to obtain access to the data
with a single request, thus significantly reducing the amount of network
traffic for both the client and the resource server.



The question the design team is struggling with is what should the Scope
string be for the "client_credentials" based access token and should there
be a single access token or can there be multiple "client_credentials"
based access tokens?



The client application currently supports the following Scope definitions:



·
FB=4_5_15;IntervalDuration=900;BlockDuration=monthly;HistoryLength=13

·
FB=4_5_16;IntervalDuration=900;BlockDuration=monthly;HistoryLength=13



There are several allowable values for the FB=, IntervalDuration=,
BlockDuration=, and HistoryLength= values.  At the moment, there are only
two defined Scope values, but as you can see, there could easily be many
more potential possibilities.



The question being discussed, is does the "client_credentials" access token
request Scope parameter need to match either of the above two strings or
can it be something altogether different?  In the event the
"client_credentials" access token request Scope parameter needs to match a
defined Scope string, does that mean that there MUST be multiple
"client_credentials" based access tokens?



Thanks in advance for helping clarify our understanding of the relationship
between "authorization_code" and "client_credentials" based access tokens.



Best regards,

Don

Donald F. Coffin

Founder/CTO



REMI Networks

22751 El Prado Suite 6216

Rancho Santa Margarita, CA  92688-3836



Phone:      [phone]

Email:       [e-mail]




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