Re: [OAUTH-WG] About Big Brother and draft-campbell-oauth-resource-indicators-00

[Vivek Biswas <[e-mail]>]

+1 to It MAY be an absolute URI, as specified by Section 4.3 of [RFC3986]".

Since the Audience Restriction can be a logical name to be interpreted by the Resource Server, if it really wants to enforce the audience check for a set of Resources it wants to protect.
Hence, a logical name can be an absolute URI or a String as well.

Regards
Vivek Biswas, CISSP
Consulting Member, Security
Oracle Corporation.



 

From: Denis [mailto:[e-mail]] 
Sent: Tuesday, November 15, 2016 3:50 AM
To: [e-mail]
Subject: [OAUTH-WG] About Big Brother and draft-campbell-oauth-resource-indicators-00

 

Hello everybody,

Since I am not present at the meeting, I read the minutes from the first session, in particular:

Brian Campbell and John did a draft allowing the client to tell the AS where it plans to use the token
draft-campbell-oauth-resource-indicators

              This enables the AS to audience restrict the access token to the resource
              Phil Hunt:  We should keep the audience restriction idea on the table

The introduction contains the following sentences:

Several years of deployment and implementation experience with OAuth 2.0 [RFC6749] has uncovered a need, in some circumstances, 
for the client to explicitly signal to the authorization sever where it intends to use the access token it is requesting.

A means for the client to signal to the authorization sever where it intends to use the access token it's requesting is important and useful. 

The document contains a "security considerations" section but unfortunately no "privacy considerations" section.

Clause 2 states:

The client may indicate the resource server(s) for which it is requesting an access token by including the
following parameter in the request.

resource

OPTIONAL. The value of the resource parameter indicates a resource server where the requested
access token will be used. It MUST be an absolute URI, as specified by Section 4.3 of[RFC3986],

With such an approach, the authorization server would have the ability to act as a Big Brother and hence to know exactly 
where the user will be performing activities.

However, some users might be concerned with their privacy, and would like to restrict the use of the access token 
to some resource servers without the authorization server knowing which are these resource servers. 

The key point is whether the information is primarily intended to the authorization server or to the resource server(s).

I believe that it is primarily intended to the resource server(s) rather than to the authorization server in order to be included 
in an access token. Obviously, the information needs to transit through the authorization sever, that should simply be copied 
and pasted into the access token. Its semantics, if any, does not necessarily needs to be interpreted by the authorization sever.

I believe that a "privacy considerations" section should be added. 

The sentence "It MUST be an absolute URI, as specified by Section 4.3 of [RFC3986]" should be removed or 
 replaced by : "It MAY be an absolute URI, as specified by Section 4.3 of [RFC3986]".

Obviously, other changes would be necessary too.

Denis