Re: [OAUTH-WG] Reevaluating Assumptions (Important!)

On Fri, Oct 2, 2009 at 9:16 AM, George Fletcher <gffletch at aol.com> wrote:

I would expect that in the Amazon case being able to reuse the URL would be beneficial, but I'm not really familiar with that use case.

For the SSO use cases, the desire is to prevent replay and make the URL one time use only. We do set cookies during the redirect process so a cache replaying those cookies could be problematic. There are a number of cache control directives that can be used for correctly implemented proxies.

A couple reasonable links on the topic

[1] http://blog.isc2.org/isc2_blog/2008/09/proxy-caches-ar.html
[2] http://www.oucs.ox.ac.uk/cache/faq.xml?splitLevel=-1
[3] http://code.google.com/speed/page-speed/docs/caching.html

However, I think this issue is bigger than just requests with URL parameters. If I access a rest resource http://photos.example.com/alice/album/vacation along with it's Authorization header, if this request goes through a proxy, the proxy will mostly likely ignore the Authorization header. Hence the next time that static URL is requested, the contents is returned. The same cache control headers the server needs to send for these specific use cases will apply to the general case as well. I'm a little behind in the lists servs. Has this issue already been solved for the general case using the Authorization header?

Thanks,
George

Eran Hammer-Lahav wrote:

Thanks James, George.

If we are going to support sending authentication credentials in the URI query, what are the requirements to make sure it works well with proxies and caches? What headers do we need to require the server to return to make sure it doesn't get cached? Do we need to require a nonce value for all signature methods to ensure making the request more unique and less likely to repeat?

In these two use cases, is there a reason for the URI to be used more than once? Can we simplify the credentials passed via the URI query to provide adequate security but without the need for a long and ugly URI with multiple oauth_ prefixed parameters?

These are valid use cases and something we need to worry about to get this new protocol deployed where other proprietary ones are deployed. But I am not that concerned about the use case mentioned earlier of 'just making it easier to send requests'. So if we support query parameters but after some processing of the parameters to make the URI simpler, that would be acceptable to me.

EHL

-----Original Message-----
From: George Fletcher [mailto:gffletch at aol.com]
Sent: Friday, October 02, 2009 5:04 AM
To: oauth at ietf.org
Cc: Eran Hammer-Lahav; Brian Eaton
Subject: Re: [OAUTH-WG] Reevaluating Assumptions (Important!)

In addition to the use case James described, we use this to enable
single sign on from a client/desktop app into a browser session. The
client signs the URL and then opens the browser with that URL. The
backend validates the signature and access token and then establishes
an
authentication session for the user.

A variant of this case is where a partner uses a back-channel
federation
call to authenticate their user to the AOL authentication service. A
successful response includes an access token and secret (the equivalent
of) which the partner can then user to sign an URL when their user
invokes an AOL service (again providing SSO).

Thanks,
George

P.S. Documentation on this signed API call can be found here:
http://dev.aol.com/authentication_for_clients#client2web

P.P.S. While these APIs are not OAuth specifically, the patterns are
needed for OAuth compliant APIs to be developed

Eran Hammer-Lahav wrote:

Can you describe the actual use case?

EHL

-----Original Message-----
From: oauth-bounces at ietf.org [mailto:oauth-bounces at ietf.org] On

Behalf

Of Brian Eaton
Sent: Thursday, October 01, 2009 9:01 PM
To: George Fletcher
Cc: oauth at ietf.org
Subject: Re: [OAUTH-WG] Reevaluating Assumptions (Important!)

On Thu, Oct 1, 2009 at 7:52 PM, George Fletcher <gffletch at aol.com>
wrote:

One use case (I think I saw it mentioned somewhere else on the

list)

where

we've used the URI parameters is when we want the server to sign a

URL and

then pass that signed value to the browser to load. This can be

done

with a

simple 302 and the signed URL. Switching to just supporting the
Authorization header will make this more difficult but probably not
impossible.

Yep. I've seen that done multiple places.

One more unexpected use of OAuth...
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