[openstack-dev] [keystone] Inherited domain roles

David Chadwick d.w.chadwick at kent.ac.uk
Mon Jun 10 15:41:22 UTC 2013



On 10/06/2013 16:02, Henry Nash wrote:
> Hi David,
>
> I wasn't suggesting that we encode "inhertitness" in the name, just
> that if you want to have a role that is non-inherited and one that is
> inherited that relate to the same type of permission, then since role
> name must be globally unique, then the two roles must have different
> names....hence potentially leading to the complication in the policy
> file.

I dont see why different role names would lead to complications in the 
policy file, since policies are there to assign different permissions to 
different roles.

What can happen is that policy files can get very large and complex, but 
that can happen regardless of whether roles are inherited or not, and 
mistakes can be made by assigning the wrong roles to users or the wrong 
permissions to roles, but again this is independent of the role definition.

regards

David
>
> Henry On 10 Jun 2013, at 15:57, David Chadwick wrote:
>
>> Hi Henry
>>
>> on the definition of inherited roles, I dont think this should be
>> part of the role name, but rather, each role should have meta
>> information attached to it, in its role table definition, that
>> indicates the properties of the role definition. In this way, you
>> can make the role definition extensible by adding new columns to
>> the table as and when needed e.g. if in future you want to have
>> global roles inherited by domains, you add a new column, say
>> GlobalToDomain, which could be a boolean with a default value of
>> false, and with a value true indicating that it is inherited from
>> global to domain. All pre-existing roles would not be of this type,
>> and therefore all pre-existing code would work without this new
>> inheritance.
>>
>> I would not alter the role-user assignment API as this should
>> simply specify the role and user and project. The code may need
>> enhancing in the future, if new types of inheritance are added, in
>> order to cater for cases where the role is wrongly specified by the
>> administrator i.e. it does not apply to the project in question
>> through lack of inheritance.
>>
>> regards
>>
>> David
>>
>> On 08/06/2013 11:38, Henry Nash wrote:
>>> So on the idea of using the role def for inheritance definition,
>>> there were a couple of things that concerned me about it:
>>>
>>> 1) While it definitely can simply the api changes required for
>>> the current requirements, I worry that we are passing the
>>> complexity on to the creation of the policy file.  Since the role
>>> names of an inherited and non-inherited role will obviously have
>>> to be different, is there a danger that policy files end up with
>>> lots of rules that have "role: xxxx and role: xxxx_inherited"?  I
>>> guess we can make the argument that since (with today's
>>> requirements at least) the only objects that will end of
>>> inheriting an assignment will be projects, the likelihood is that
>>> the api lines in the policy file that contains inherited and
>>> non-inherited will be different, hence avoiding the problem.
>>> However, if, in the future, we were to expand inheritance to
>>> support all domains, or all projects in all domains, then this
>>> problem would arise for domain-relevant apis lines in the policy
>>> file.
>>>
>>> 2) If, again, in the future we support inheritance across all
>>> domains/projects - would we need to more fine grained control of
>>> the inheritance?  For instance, we want a role that was inherited
>>> by all domains, but not the projects in each domain?  Perhaps,
>>> one could imagine expanding the role-def to somehow indicate this
>>> (maybe rather than just having a simple "inherited" boolean, we
>>> specify "project_inherited", to which we could, in the future,
>>> add "domain_inherited"?).  We also have the problem of how you
>>> assign such a role?  I guess you would still need some kind of
>>> modification to the assignment APIs to indicate "all domains"
>>> (perhaps the "domains/*" that was suggested)?
>>>
>>> I'd be interested in views on the above - I'm Ok fi we decide
>>> that role-def is the right way to go, but want to make sure we
>>> clearly understand how we would expand this in the future.
>>>
>>> Henry On 7 Jun 2013, at 18:12, Dolph Mathews wrote:
>>>
>>>>
>>>>
>>>> On Thu, Jun 6, 2013 at 5:48 AM, David Chadwick
>>>> <d.w.chadwick at kent.ac.uk <mailto:d.w.chadwick at kent.ac.uk>>
>>>> wrote:
>>>>
>>>> Hi Henry
>>>>
>>>> My take on this is that whether a role is automatically
>>>> inheritable or not should be an attribute of the role itself,
>>>> and should be independent of who the role is assigned to.
>>>> Therefore when the role is initially defined, it should be
>>>> stated by the Keystone admin whether it is an inherited role or
>>>> not.
>>>>
>>>> Role assignment is a separate issue and should not be confused
>>>> with the basic definition of the role. Role assignment should
>>>> simply be a matter of naming the subject (domain, project or
>>>> user) and the role. If you dont want the role to be inherited
>>>> then use a non-inheritable role.
>>>>
>>>> The problem with all the APIs below is that they conflate role
>>>> definition and role assignment together in the same API call.
>>>> There should be no need to have user_ids in the definition of
>>>> a role. Similarly there should be no mention of inherited in
>>>> the assignment of a role to a user.
>>>>
>>>> regards
>>>>
>>>> David
>>>>
>>>> +1; I really like the simplicity of this approach, and it
>>>> sounds like something we can migrate to easily (e.g. default
>>>> inheritable=False for existing roles). Then global role
>>>> assignments would follow an API like:
>>>>
>>>> GET /users/{user_id}/roles  # list global roles HEAD
>>>> /users/{user_id}/roles/{inheritable_role_id}  # check if a
>>>> global role is assigned PUT
>>>> /users/{user_id}/roles/{inheritable_role_id}  # assign a global
>>>> role DELETE /users/{user_id}/roles/{inheritable_role_id}  #
>>>> revoke a global role
>>>>
>>>> where a non-inheritable role assigned a user without a domain
>>>> or project for context wouldn't make any sense. In fact,
>>>> assigning an inheritable role to a user on a project wouldn't
>>>> be very useful (as it wouldn't inherit to anything in the core
>>>> API), but I don't see a reason to deny it.
>>>>
>>>>
>>>> On 05/06/2013 15:31, Henry Nash wrote:
>>>>
>>>> Hi
>>>>
>>>> As per the discussion during the keystone IRC meeting
>>>> yesterday, I have been reviewing the proposals for this
>>>> functionality.  There have been two objections to the current
>>>> proposal (which can be found here:
>>>> https://review.openstack.org/#__/c/29781/10
>>>> <https://review.openstack.org/#/c/29781/10>), which are:
>>>>
>>>> 1) The api changes should allow for a logical, generic future
>>>> extension for support of inherited roles across all domains
>>>> etc., should we chose to go that route 2) The use of a single
>>>> api to list the various grants, filtered by a query string if
>>>> necessary.
>>>>
>>>> My proposal for handling these two objections is as follows:
>>>>
>>>> 1) API extensions.
>>>>
>>>> There are several aspects of inherited roles that we are trying
>>>> to cement, which are:
>>>>
>>>> a) The are dynamic - i.e. this isn't a case of a short hand for
>>>> saying add this role to all the current projects in the domain
>>>> - rather it is a role assignment that is attached to the domain
>>>> but is added to the effective roles of any project (now and in
>>>> the future) that exists in this domain b) The are separate from
>>>> a role that is on the domain itself - i.e.  we need to ensure
>>>> that we keep separate inherited and non-inherited roles. c)
>>>> Maintain the philosophy that If you can create a role
>>>> assignment with a given API, there should be an equivalent to
>>>> read it back and delete it (i.e. you mustn't have the case
>>>> where, for instance you can list a grant, but can't delete it
>>>> at the conceptual level)
>>>>
>>>> The current proposal had been to do this by adding an
>>>> "inherited" component of the url for create, check and delete
>>>> grants to a domain, e.g.
>>>>
>>>> PUT /domains/{domain_id}/users/{__user_id}/roles/{role_id} PUT
>>>> /domains/{domain_id}/users/{__user_id}/roles/{role_id}/__inherited
>>>>
>>>>
GET /domains/{domain_id}/users/{__user_id}/roles/{role_id}
>>>> GET
>>>> /domains/{domain_id}/users/{__user_id}/roles/{role_id}/__inherited
>>>>
>>>>
DELETE /domains/{domain_id}/users/{__user_id}/roles/{role_id}
>>>> DELETE
>>>> /domains/{domain_id}/users/{__user_id}/roles/{role_id}/__inherited
>>>>
>>>>
etc.
>>>>
>>>> A counter proposal has been made to expand this, along this
>>>> lines of:
>>>>
>>>> Role applicable to all projects within a domain PUT
>>>> /domains/{domain_id}/users/{__user_id}/roles/{role_id}/__projects
>>>>
>>>>
>>>>
Roles inherited by all projects in all domains
>>>> PUT /usrs/{user_id}/roles/{role___id}/projects
>>>>
>>>> Roles inherited by all domains, at the domain level PUT
>>>> /usrs/{user_id}/roles/{role___id}/domains
>>>>
>>>> While I understand the desire to have extensibility if we wish
>>>> to provide more "global-ness" of roles, I think the above
>>>> proposal is less clear about whether these assignments are
>>>> dynamic (see item a) above).  How about this as a counter
>>>> proposal:
>>>>
>>>> Role applicable inherited by all projects within a domain (this
>>>> is the same as the current proposal) PUT
>>>> /domains/{domain_id}/users/{__user_id}/roles/{role_id}/__inherited
>>>>
>>>>
>>>>
Roles inherited by all projects in all domains - if we were to
>>>> ever support this (not part of the current proposal) PUT
>>>> /domains/users/{user_id}/__roles/{role_id}/inherited
>>>>
>>>> Roles inherited by all domains, at the domain level - if we
>>>> were to ever support this (not part of the current proposal)
>>>> PUT  /domains/users/{user_id}/__roles/{role_id}/inherited
>>>>
>>>> To go along with the above, you would have the respective GET,
>>>> CHECK & DELETE versions of those apis.
>>>>
>>>> 2) Single vs multiple apis I think this comment is actually
>>>> misplaced in the gerrit review, and is intended to directed at
>>>> the api extensions I proposed to allow the list of a users
>>>> "effective" roles on a project (i.e. directly assigned, those
>>>> by virtue of group membership and inheritance from the parent
>>>> domain).  For this, I proposed adding an optional "effective"
>>>> query parameter to each of:
>>>>
>>>> List user's roles on project: `GET
>>>> /projects/{project_id}/users/{__user_id}/roles List group's
>>>> roles on project: `GET
>>>> /projects/{project_id}/groups/__{group_id}/roles Check user's
>>>> role on project: `GET
>>>> /projects/{project_id}/users/{__user_id}/role/{role_id} Check
>>>> group's roles on project: `GET
>>>> /projects/{project_id}/groups/__{group_id}/role/{role_id}
>>>>
>>>> e.g. GET
>>>> /projects/{project_id}/users/{__user_id}/roles?effective
>>>> ...would get you the effective roles the user has on that
>>>> project, as opposed to only the directly assigned ones if you
>>>> issue the call without the "effective" query parameter.
>>>>
>>>> Dolph and I had already been discussing that the existing v3
>>>> api of:
>>>>
>>>> GET /users/{user_id}/roles
>>>>
>>>> ...which is meant to return all the role assignments for a
>>>> user, but is in fact broken in the current Grizzly code (it
>>>> always returns an error).  So I agree with the proposal that we
>>>> should scrap the "effective" query parameter for the specific
>>>> list/check calls for the project - and instead properly
>>>> implement the "get all assignments for a user" call. I propose
>>>> the amended spec for this call is:
>>>>
>>>> #### List a user's effective role assignments: `GET
>>>> /users/{user_id}/role-__assignments`
>>>>
>>>> query_string: page (optional) query_string: per_page (optional,
>>>> default 30) query_string: id, project_id, domain_id
>>>>
>>>> Response:
>>>>
>>>> Status: 200 OK
>>>>
>>>> [ { "id": "--role-id--", "name": "--role-name--", "project_id":
>>>> "--project-id--", "source": { "direct": true,  (optional)
>>>> "domain_inherited: "--domain-id--", (optional)
>>>> "group_membership: "--group-id--" (optional) } }, {
>>>> "domain_id": "--domain-id--", "id": "--role-id--", "name":
>>>> "--role-name--", "source": { "direct": true, (optional)
>>>> "group_membership: "--group-id--" (optional) } } ]
>>>>
>>>> The "source" structure must have at least one of the values
>>>> given above (and could have more than one, e.g. both
>>>> domain_inherited and global_membership for a project where the
>>>> role is due to a group role that is inherited from the domain).
>>>> If were even to support global roles across all domains, then
>>>> we would extend the "source structure" accordingly.   I'm open
>>>> to other options for the above format. however, so comments
>>>> welcome.
>>>>
>>>> Does this sounds like a reasonable plan overall?
>>>>
>>>> Henry
>>>>
>>>>
>>>>
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>>>
>>>>
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