Open Stack

FYI: We were thinking about using the new Keystone policy API, but fell back to using files on the file system due to not having a way to retrieve the policies from Keystone other than with an ID string. After saving the policy file you need to save the policy ID somewhere so you might as well just save the policy file as well. If the policy table also had a name field, then the policy file could be saved during OpenStack installation and retrieved later by each service using some algorithm on its name.

Mark

From: Dolph Mathews [mailto:dolph.mathews at gmail.com]
Sent: Monday, September 16, 2013 9:19 AM
To: OpenStack Development Mailing List
Subject: Re: [openstack-dev] WebUI and user roles


On Mon, Sep 16, 2013 at 11:01 AM, Adam Young <ayoung at redhat.com<mailto:ayoung at redhat.com>> wrote:
Looks like this has grown into a full discussion.  Opening up to the dev mailing list.

On 09/16/2013 10:43 AM, Lyle, David (Cloud Services) wrote:
I did run into a couple of fundamental limitations with the policy API as implemented in Keystone.

1)  policy_list and policy_get are admin_required by default in the policy file.  Obviously this can be changed in the policy file itself, but this is a bad default.  A regular user is most in need of policy rule enforcement so the existing default does not make sense from a UI perspective.
Hmmm, this sounds like a mismatch of expectations.  I would think that the Horizon server would fetch the policy as an admin user, not the end user, and use that to tailor their UX.  It would only be a problem if that tailoring was done on the Client side in Javascript.  Why would it matter what access control for the policy was?  Why would the end user be requesting the policy?

2)  The 3 param/return fields supported by the policy API are: blob, id, type (mime-type).  When trying to utilize multiple policy files (blobs) from several services we need a way to map the blob to a service type to know which rule set to apply.  I had considered lumping all the policy blobs into one, but there is no requirement that each policy rule will begin with e.g., "identity:" and several blobs could implement a rule "default" which could be specified differently.  So, I believe a service_type parameter is necessary.  Additionally, is there anything barring nova from uploading multiple policy blobs (perhaps different), each getting unique IDs, and then having several varying compute policy blobs to choose from?  Which one wins?
I haven't looked deeply at the policy API until now:   It looks broken.  I would not be able to tell just from reading the code how to map a policy file to the service that needed it.  I would think that, upon service startup, it would request the policy file that mapped to it, either by endpoint with a fallback to a pre-service call.

We stopped short of any policy -> service/endpoint mapping because there were mixed expectations about how that should be done and no clear use case that fetching policies by ID / URL didn't satisfy a bit more simply.


I would think that you would make a tree out of the rules.  At the root would be policy.  Underneath that would be the service, (then the endpoint in the future when we support multiple per service) and then the rules underneath those.  The rules would be a json dumps of the blob get from the policy_api.



Having devstack load the policy files into keystone would help, but 1 and 2 need to be addressed before those files are usable in Horizon.

Thanks,
David

-----Original Message-----
From: Adam Young [mailto:ayoung at redhat.com<mailto:ayoung at redhat.com>]
Sent: Monday, September 16, 2013 8:16 AM
To: Julie Pichon
Cc: Matthias Runge; Gabriel Hurley; Lyle, David (Cloud Services)
Subject: Re: WebUI and user roles

On 09/16/2013 07:33 AM, Julie Pichon wrote:
"Adam Young" <ayoung at redhat.com<mailto:ayoung at redhat.com>> wrote:
Gabriel and I talked at the last summit about how Horizon could
figure out what to show the user based on the roles that the user
had.  At the time, I was thinking it wasn't something we could figure out at run time.

I was wrong.

The answer is plain.  We have the policy files in Keystone already,
we just don't parse them.  Horizon has all the information it needs
to figure out "based on a token, what can this user do?"

I'm not certain how to make use of this, yet, but the kernel of the
idea is there.
Thanks Adam. David Lyle implemented RBAC functionality based on policy
files in Havana [0]. I think one of the problems he found was that
although policy files are in use, most services currently do not
upload them to Keystone so they are not yet queryable (?).
That is true, but it is a deployment issue that is easily solvable. We can have devstack, packstack, and whatever else, upload the policy files at the start.  They are all in the various deployments, so it is really a trivial step to load them into Keystone.
Regards,

Julie


[0] https://blueprints.launchpad.net/horizon/+spec/rbac


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--

-Dolph
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