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On Wed, Jan 18, 2017 at 11:23 AM, Brant Knudson <blk at acm.org> wrote:

>
>
> On Wed, Jan 18, 2017 at 9:58 AM, Dave McCowan (dmccowan) <
> dmccowan at cisco.com> wrote:
>
>>
>> On Mon, Jan 16, 2017 at 7:35 AM, Ian Cordasco <sigmavirus24 at gmail.com>
>> wrote:
>>
>>> Hi everyone,
>>>
>>> I've seen a few nascent projects wanting to implement their own secret
>>> storage to either replace Barbican or avoid adding a dependency on it.
>>> When I've pressed the developers on this point, the only answer I've
>>> received is to make the operator's lives simpler.
>>>
>>>
>> This is my opinion, but I'd like to see Keystone use Barbican for storing
>> credentials. It hasn't happened yet because nobody's had the time or
>> inclination (what we have works). If this happened, we could deprecate the
>> current way of storing credentials and require Barbican in a couple of
>> releases. Then Barbican would be a required service. The Barbican team
>> might find this to be the easiest route towards convincing other projects
>> to also use Barbican.
>>
>> - Brant
>>
>>
>> Can you provides some details on how you'd see this work?
>> Since Barbican typically uses Keystone to authenticate users before
>> determining which secrets they have access to, this leads to a circular
>> logic.
>>
>> Barbican's main purpose is a secret manager.  It supports a variety of
>> RBAC and ACL access control methods to determine if a request to
>> read/write/delete a secret should be allowed or not.  For secret storage,
>> Barbican itself needs a secure backend for storage.  There is a
>> customizable plugin interface to access secure storage.  The current
>> implementations can support a database with encryption, an HSM via KMIP,
>> and Dogtag.
>>
>>
> I haven't thought about it much so don't have details figured out.
> Keystone stores many types of secrets for users, and maybe you're thinking
> about the user password being tricky. I'm thinking about the users' EC2
> credentials (for example). I don't think this would be difficult and would
> involve creating a credentials backend for keystone that supports barbican.
> Maybe have a 'keystone' project for credentials keystone is storing? If
> you're familiar with the Barbican interface, compare with keystone's
> credential interface[0].
>
> [0] http://git.openstack.org/cgit/openstack/keystone/tree/
> keystone/credential/backends/base.py#n26
>
> - Brant
>
>
The user passwords and the MFA tokens would be particularly difficult as
they are to be used for authentication purposes. Anything tied to the main
AuthN path would require something akin to a "service wide" secret store
that could be accessed/controlled by keystone itself and not "on behalf of
user" where the user still owns the data stored in barbican.

I can noodle over this a bit more and see if I can come up with a mechanism
that (without too much pain) utilizes barbican for the AuthN paths in the
current architecture.

I think it is doable, but I hesitate to make Keystone's AuthN path rely on
any external service so we don't run into a circular dependency of services
causing headaches for users. Keystone has provided a fairly stable base for
other projects including Barbican to be built on.

Now... If the underlying tech behind Barbican could be pushed into keystone
as the credential driver (and possibly store for passwords?) without
needing to lean on Barbican's Server APIs (restful), I think that is quite
viable and could be of value since we could offload the credentials to a
more secure store without needing a "restful service" that uses keystone as
an AuthN/AuthZ source to determine who has access to what secret.

--Morgan
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