Is this spec still alive? I'm working on the spec for Ironic integration of 
Keystone policy, and like some of the items in the draft, but obviously they 
aren't binding and I can't really reference them unless the spec merges or at 
least shows progress towards merging.

Thanks,
Jay Faulkner
OSIC

On Jan 31, 2016, at 6:15 PM, Adam Young 
<ayo...@redhat.com<mailto:ayo...@redhat.com>> wrote:

On 01/30/2016 08:24 PM, Henry Nash wrote:

On 30 Jan 2016, at 21:55, Adam Young 
<<mailto:ayo...@redhat.com>ayo...@redhat.com<mailto:ayo...@redhat.com>> wrote:

On 01/30/2016 04:14 PM, Henry Nash wrote:
Hi Adam,

Fully support this kind of approach.

I am still concerned over the scope check, since we do have examples of when 
there is more than one (target) scope check, e.g.: an API that might operate on 
an object that maybe global, domain or project specific - in which case you 
need to “match up with scope checks with the object in question”, for example 
for a given API:

If cloud admin, allow the API
If domain admin and the object is domain or project specific, then allow the API
If project admin and the object is project specific then allow the API

Today we can (and do with keystone) encode this in policy rules. I’m not clear 
how the “scope check in code” will work in this kind of situation.
I originally favored an approach that a user would need to get a token scoped 
to a resource in order to affect change on that resource, and admin users could 
get tokens scoped to anything,  but I know that makes things harder for 
Administrators trying to fix broken deployments. So I backed off on that 
approach.

I think the right answer would be that the role check would set some value to 
indicate it was an admin override.  So long as the check does not need the 
actual object from the database, t can perform whatever logic we like.

The policy check deep in the code can be as strict or permissive as it desires. 
 If there is a need to re-check the role for an admin check there, policy can 
still do so.  A role check that passes at the Middleware level can still be 
blocked at the in-code level.

"If domain admin and the object is domain or project specific, then allow the 
API" is trh tricky one, but I don't think we even have a solution for that now. 
 Domain1->p1->p2->p3 type hierarchies don't allow operations on p3 with a token 
scoped to Domain1.

So we do actually support things like that, e.g. (from the domain specific role 
additions):

”identity:some_api": role:admin and project_domain_id:%(target.role.domain_id)s 
   (which means I’m project admin and the domain specific role I am going to 
manipulate is specific to my domain)

….and although we don’t have this in our standard policy, you could also write

”identity:some_api": role:admin and domain_id:%(target.project.domain_id)s    
(which means I’m domain admin and I can do some operation on any project in my 
domain)

Yeah, we do some things like this in the Keystone policy file, but not in 
remote services, yet, and it would only work for Domain of the project, not for 
any arbitrary project in the chain under Domain1:  roles on p1 or P2 would have 
to be inherited in order to affect any change on resources in 3.



I think that in those cases, I would still favor the user getting a token from 
Keystone scoped to p3, and use the inherited-role-assignment approach.



Henry

On 30 Jan 2016, at 17:44, Adam Young 
<ayo...@redhat.com<mailto:ayo...@redhat.com>> wrote:

I'd like to bring people's attention to a Cross Project spec that has the 
potential to really strengthen the security story for OpenStack in a scalable 
way.

"A common policy scenario across all projects" 
<https://review.openstack.org/#/c/245629/> 
https://review.openstack.org/#/c/245629/

The summary version is:

Role name or pattern                    Explanation or example
-------------------------------------:--------------------------------------------------
admin                                :  Overall cloud admin
service                              :  for service users only, not real humans
{service_type}_admin                 :  identity_admin, compute_admin, 
network_admin etc.
{service_type}_{api_resource}_manager: identity_user_manager,
                                       compute_server_manager, 
network_subnet_manager
observer                             :  read only access
{service_type}_observer              : identity_observer, image_observer


Jamie Lennox originally wrote the spec that got the ball rolling, and Dolph 
Matthews just took it to the next level.  It is worth a read.

I think this is the way to go.  There might be details on how to get there, but 
the granularity is about right.
If we go with that approach, we might want to rethink about how we enforce 
policy.  Specifically, I think we should split the policy enforcement up into 
two stages:

1.  Role check.  This only needs to know the service and the api resource.  As 
such, it could happen in middleware.

2. Scope check:  for user or project ownership.  This happens in the code where 
it is currently called.  Often, an object needs to be fetched from the database

The scope check is an engineering decision:  Nova developers need to be able to 
say where to find the scope on the virtual machine, Cinder developers on the 
volume objects.

Ideally, The python-*clients, Horizon and other tools would be able to 
determine what capabilities a given token would provide based on the roles 
included in the validation response. If the role check is based on the URL as 
opposed to the current keys in the policy file, the client can determine based 
on the request and the policy file whether the user would have any chance of 
succeeding in a call. As an example, to create a user in Keystone, the API is:

POST https://hostname:port/v3/users

Assuming the client has access to the appropriate policy file, if can determine 
that a token with only the role "identity_observer" would not have the ability 
to execute that command.  Horizon could then modify the users view to remove 
the "add user" form.

For user management, we want to make role assignments as simple as possible and 
no simpler.  An admin should not have to assign all of the individual roles 
that a user needs.  Instead, assigning the role "Member" should imply all of 
the subordinate roles that a user needs to perform the standard workflows.  
Expanding out the implied roles can be done either when issuing a token, or 
when evaluating the policy file, or both.

I'd like to get the conversation on this started here on the mailing list, and 
lead in to a really productive set of talks at the Austin summit.



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