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[Joe Savak <joe.savak@xxxxxxxxxxxxx>]

Hi Joe,
	If I'm working across multiple tenants, I'd prefer one token that I can securely handle that proves access rights to the tenants I'm working with. Handling multiple tokens increases the complexity of clients needing to provide multi-tenancy access to an authenticated identity. It also adds more calls to keystone. 

Again, I think that having the keystone reference implementation restrict tokens to 1 tenant is fine. We shouldn't have such arbitrary restrictions in the API contract though. It needs to be extensible and flexible to allow for the all sorts of use cases that are likely to occur.

Thanks,
joe

-----Original Message-----
From: heckj [mailto:heckj@xxxxxxx] 
Sent: Tuesday, November 13, 2012 3:59 PM
To: Joe Savak
Cc: OpenStack Development Mailing List; openstack@xxxxxxxxxxxxxxxxxxx (openstack@xxxxxxxxxxxxxxxxxxx)
Subject: Re: [Openstack] [openstack-dev] Fwd: [keystone] Tokens representing authorization to projects/tenants in the Keystone V3 API

Hey Joe:

Currently a user scoped token doesn't include a service catalog - mostly because I think the service catalog generally requires tenant_id's to interpolate into the values to provide it. That doesn't mean we can't put in/include service catalog endpoints where that value doesn't need to be determined.

I'm also questioning the value of providing a token scoped to all tenants associated with a user - that seems to have the same value as just using a user token. 

In fact, even if we allow some arbitrary set of tenants to be scoped into a token along with a user, what on earth should be in the service catalog? Endpoints relevant to every possible tenant?

This just seems to be a potential explosion of data that is poorly scoped from a security perspective.

-joe

On Nov 13, 2012, at 1:42 PM, Joe Savak <joe.savak@xxxxxxxxxxxxx> wrote:
> Will user-scoped token include the full service catalog? 
> 
> Also, I thought the consensus was to allow the API contract to be flexible on how many tenants we can scope the token to. The ref impl can enforce 1 tenant-scoped token. Are we diverging from this?
> 
> Thanks,
> joe
> 
> -----Original Message-----
> From: openstack-bounces+joe.savak=rackspace.com@xxxxxxxxxxxxxxxxxxx [mailto:openstack-bounces+joe.savak=rackspace.com@xxxxxxxxxxxxxxxxxxx] On Behalf Of heckj
> Sent: Tuesday, November 13, 2012 1:34 PM
> To: OpenStack Development Mailing List
> Cc: openstack@xxxxxxxxxxxxxxxxxxx (openstack@xxxxxxxxxxxxxxxxxxx)
> Subject: Re: [Openstack] [openstack-dev] Fwd: [keystone] Tokens representing authorization to projects/tenants in the Keystone V3 API
> 
> 
> On Nov 13, 2012, at 11:01 AM, Jorge Williams <jorge.williams@xxxxxxxxxxxxx> wrote:
>> On Nov 13, 2012, at 11:35 AM, heckj wrote:
>>> So maintaining a token scoped to just the user, and a mechanism to scope it to a tenant sound like all goodness. We can absolutely keep the API such that it can provide either. 
>>> 
>>> Right now, our auth_token middleware implicitly requires a tenant in that scoping to work. If someone wanted to support a token scoped to just a user for the services, they'd need a different middleware there. Keystone as a service *doesn't* use the auth_token middleware, so with the V3 API we can make it provide services appropriately based on a token scoped only to the user.
>>> 
>>> All that in place, allow a token to be indeterminate scoped to multiple tenants is fraught with security flaws, and if we continue to provide unscoped tokens, that should obviate the need for token scoped to multiple tenants. 
>> 
>> I'm not sure I'm following you there.  I don't see how unscoped tokens obviate the need to scope to multiple tenants, these may be driven by  different concerns. 
>> 
>> Again, I think we need to have some flexibility in how we scope tokens. The API should be flexible enough to support different models -- I think that scoping a token to multiple tenants is useful in cases such as delegation -- where a single identity may be issued revokable access to a set of resources in multiple projects.
> 
> The consensus from the folks weighing in on this from a security perspective seems to be that it's kosher to restrict tokens further (the least privilege thing). Broadening the scope to multiple tenants or sets of tenants doesn't appear to follow those best practices. If you wanted to accept a less-scoped token than the scoped to single tenant, you can accept and use a user-scoped token, at least by my read.
> 
> -joe
> 
> 
> 
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