[Pulp-dev] RBAC Status Thread

[Brian Bouterse]

Another productive RBAC day! See the latest code at the links below. Here's
what's new:

* policy is now shorter thanks to machinery checking both model-level and
object-level permissions with one call. The other two are also available
* sync is now restricted on both 'modify_repo_content' permissions AND read
permission on the remote being used to sync
* modify is now restricted on 'modify_repo_content' permission
* moved the permission checking machinery to be "global checks"
* added data migration that sets is_staff=True, so the django-admin
interface can be used (this is getting a slight rework tomorrow morning tho)

https://github.com/pulp/pulp_file/compare/master...bmbouter:rbac-PoC
https://github.com/pulp/pulpcore/compare/master...bmbouter:rbac-PoC

Tomorrow's demo is advertised here. It will also include an overview of
some of the unsolved problems with some possible solutions.

Cheers,
Brian


On Tue, Jun 30, 2020 at 5:08 PM Brian Bouterse <bmbouter at redhat.com> wrote:

> Today I accomplished a few more things:
>
> * finished my ldap notes: https://hackmd.io/ED9UpscNSRW86Le3xNzVeg
> * moving the checks from a mixin to be "global checks" so they are
> available everywhere, this is a feature from drf-access-policy:
> https://rsinger86.github.io/drf-access-policy/reusable_conditions/
> * added a has_obj_or_module_perms method allowing policy writers to just
> use that instad of carrying "two entries" in the policy, one for
> model-level, one for object-level
>
> Need to:
> * clean up the "sync" policy code
> * Add global condition check facilities for the perms of a 'remote' param
> * add policy language restricting the /modify/ endpoint also for
> FileRepository
> * push my code
>
> New Challenge: We need to also have the permissions assignments happen for
> objects created by tasks. django-guardian recommends this happen inside
> signals (
> https://django-guardian.readthedocs.io/en/latest/userguide/assign.html#assigning-permissions-inside-signals).
> The challenge (thanks @mdellweg for identifying) is that the user/group
> context information is well-known in the viewset but not in a task. Soooooo
> ... the idea is:
>
> 1. Switch the perms addition to the model itself via signals so it's
> automatic everywhere (including in tasks)
> 2. Preserve the user and group "request context" into the tasking system.
> I can see a straightforward path to how to do this so I plan to prototype
> this soon also.
>
> Feedback is welcome!
>
>
>
>
>
> On Fri, Jun 26, 2020 at 6:16 PM Brian Bouterse <bmbouter at redhat.com>
> wrote:
>
>> Today I got the "sync" RBAC working, but I need to give it some more
>> thought. The extra challenge with this parts is that "having permission to
>> read a Remote" is already defined in one place, on FileRemoteAccessPolicy,
>> yet the AccessPolicy that needs to perform the enforcement is
>> FileRepositoryAccessPolicy for its "sync" action. This is a bit challenging
>> considering the following goals:
>>
>> * We don't want to duplicate code, e.g. having the
>> FileRepositoryAccessControl begin to inspect permissions for FileRemote
>> directly, when FileRemoteAccessPolicy already does that
>> * Currently permissions are granted at two levels: Model-level and
>> File-level permissions and permissions are granted from either level.
>> * We want to keep the policy in charge. If we start to bury the behavior
>> in methods and functions then policy writers are no longer in control.
>>
>> All of ^ together tells me that I should work on creating two things next:
>> 1) A way for policy writers to express which parameter refers to objects
>> that also need their permissions checked. For example the policy should be
>> able to say "remote is a parameter and it needs X permission". This is akin
>> to the has_module_level_perms and has_obj_level_perms here except we also
>> need to identify which parameter is being checked instead of the object the
>> AccessPolicy itself governs.
>> 2) A single way to check model-level and object-level permissions at once
>> and allow if *either* passes. We would still allow policy writers to call
>> either model-level or file-level checks also.
>>
>> I'll work on ^ next. Ideas and feedback are welcome. I pushed no new code
>> today because it's a mess and not runnable at my stopping point.
>>
>>
>> On Thu, Jun 25, 2020 at 6:18 PM Brian Bouterse <bmbouter at redhat.com>
>> wrote:
>>
>>> Here's another push to the branch (it includes the following
>>> additions):
>>> https://github.com/pulp/pulp_file/compare/master...bmbouter:rbac-PoC?expand=1
>>>
>>> * A FileRepositoryAccessPolicy which provides RBAC for Repositories (not
>>> yet sync)
>>> * A new Mixin allowing the two policies to share some common components
>>>
>>> Next up:
>>> * have the pup_file define the fileContentAdmin group programmatically
>>> * Extend the FileRepositoryAccessPolicy to restrict sync operations
>>> * Write up and organize the PoC into a clear, organized format
>>>
>>> Also of interest today @ttereshc and I had a great convo asking what to
>>> do about potential problems when we use Django groups to be a "role". My
>>> write up will address this in more detail than I can go into here. We are
>>> also looking at what the django-role-permissions project could offer us:
>>> https://django-role-permissions.readthedocs.io/en/stable/utils.html
>>>
>>> I expect the PoC to be done by tomorrow and write-up by Monday, so I'm
>>> going to schedule the public review meeting for next week towards the end
>>> of the week.
>>>
>>>
>>> On Wed, Jun 24, 2020 at 5:49 PM Brian Bouterse <bmbouter at redhat.com>
>>> wrote:
>>>
>>>> Moar progress! Today the following things got done: Today's changes are
>>>> available here:
>>>> https://github.com/pulp/pulp_file/compare/master...bmbouter:rbac-PoC?expand=1
>>>>
>>>> * Got scoped querysets working! This restricts list views to only show
>>>> objects a user has permissions to view. A db reset was all that was needed
>>>> I think I didn't have all the changes in when I applied my earlier
>>>> migrations
>>>> * Added "detail view" restriction, and while it's in the policy and
>>>> working DRF does a strange thing on "retrieve" where if it's not in the
>>>> queryset (due to scoping ^) the user receives a 404, not a permission denied
>>>> * Got permissions cleaning up on resource deletion now too
>>>>
>>>> Next up:
>>>> * have the pup_file define the fileContentAdmin group programmatically
>>>> * Make similar policies for FileRepository which governs itself and the
>>>> "sync" action
>>>> * Write up and organize the PoC into a clear, organized format
>>>>
>>>> Questions and feedback are welcome!
>>>>
>>>> On Tue, Jun 23, 2020 at 5:54 PM Brian Bouterse <bmbouter at redhat.com>
>>>> wrote:
>>>>
>>>>> Lots of progress today! I have a mostly-complete policy for RBAC for
>>>>> FileRemote. It's surprising how little code all of this ended up being.
>>>>>
>>>>> Here's the actual RBAC stuff, it's all in pulp_file:
>>>>> https://github.com/pulp/pulp_file/compare/master...bmbouter:rbac-PoC?expand=1
>>>>> Here's the parts that go in core. Note the LDAP stuff is all optional,
>>>>> the only real requirement are two lines 1) enabling guardian in
>>>>> INSTALLED_APPS and 2) adding it as an AuthenticationBackend:
>>>>> https://github.com/pulp/pulpcore/compare/master...bmbouter:rbac-PoC
>>>>>
>>>>> I have some "how to use notes" here:
>>>>> https://hackmd.io/DRqGFyRsSDmN7E4TtOPf-w  The idea is that it
>>>>> implements the FileRemote portions of this requirements docs:
>>>>> https://hackmd.io/kZ1oYp8TTkeuC5KL_ffjGQ
>>>>>
>>>>> Here is the short list of things for FileRemote that still don't work.
>>>>> This is mainly so I remember what to do next. :)
>>>>> * The get_objects_for_user
>>>>> <https://django-guardian.readthedocs.io/en/latest/api/guardian.shortcuts.html#get-objects-for-user>
>>>>> from DjangoGuardian I don't think it likes Master/Detail or maybe it's
>>>>> how/where I'm using it. I haven't yet debugged this. For this reason it
>>>>> doesn't provide list restriction
>>>>> * It still needs "detail view" restriction. This is straightforward.
>>>>> * The group should be programmatically defined, in this case it was
>>>>> "defined in LDAP". It could *also* live in LDAP (or other external group
>>>>> definition system) but the plugin builds permissions off of it so it should
>>>>> also define it. This is easy.
>>>>>
>>>>> Feedback is welcome. I'm going to continue building this and then
>>>>> schedule a public review of FileRemote, Content modification for file
>>>>> repos, and sync restriction next week.
>>>>>
>>>>>
>>>>>
>>>>> On Mon, Jun 22, 2020 at 5:14 PM Brian Bouterse <bmbouter at redhat.com>
>>>>> wrote:
>>>>>
>>>>>> # ldap PoC updates
>>>>>> Now users, groups, and group membership are populating from ldap
>>>>>> automatically on login (with auth backed by ldap also)! I'll be sharing my
>>>>>> configs for both ldap and how to configure django-auth-ldap
>>>>>> <https://django-auth-ldap.readthedocs.io/en/latest/example.html>
>>>>>> here soon in an organized way. This was done with django-auth-ldap and 0
>>>>>> customization to pulp code. It's 100% enabled through settings so this work
>>>>>> is more of an approach we can document for users that they can enable and
>>>>>> not a feature Pulp ships itself.
>>>>>>
>>>>>> # django-admin progress
>>>>>> Thanks to @alikins existing PRs, I got django admin enabled and able
>>>>>> to view/edit users, groups, group membership, and permissions at both the
>>>>>> user and group levels. This is important because this will be the primary
>>>>>> mechanism of administrators. This part is looking good.
>>>>>>
>>>>>> # new resources to help us out
>>>>>> Through collaboration with @ttereshc and someone off list named
>>>>>> @adelton (who actually authored this reference approach
>>>>>> <https://www.adelton.com/django/external-authentication-for-django-projects>
>>>>>> I referenced early on in this exploration), this very cool repository of
>>>>>> testing tools was identified:
>>>>>> https://github.com/adelton/webauthinfra  It has a treasure trove of
>>>>>> testing containers which Pulp devs in the future can test against. It keeps
>>>>>> the user/group check in the apache which is fine alternative to the
>>>>>> django-auth-ldap approach above. Pulp doesn't have to choose, it could work
>>>>>> with either just configured differently. The pending PoC outline will go
>>>>>> over these alternative approaches in detail.
>>>>>>
>>>>>> # Next Steps:  back to the PoC itself
>>>>>> Now that we have demonstrated good options of external
>>>>>> users/groups/membership loading into Pulp we can confidently move back to
>>>>>> finishing the RBAC PoC itself. I've started back into this. So the
>>>>>> remaining work are the two steps below:
>>>>>>
>>>>>> 1. Finish the PoC that uses RBAC to restrict remotes, sync, and
>>>>>> repository content modification. Currently I prototyped restriction of
>>>>>> operations on Remotes, but I need to replicate the access policies to
>>>>>> Repositories and Sync next.
>>>>>> 2. Write it up and share it.
>>>>>> 3. Schedule public meeting to review it (targeting next-week)
>>>>>>
>>>>>>
>>>>>>
>>>>>> On Fri, Jun 19, 2020 at 5:09 PM Brian Bouterse <bmbouter at redhat.com>
>>>>>> wrote:
>>>>>>
>>>>>>> I got the LDAP users both authenticating and importing into Pulp!
>>>>>>> Next I'll do the groups and then I think the ldap parts will be done.
>>>>>>>
>>>>>>> FYI: I'm going to write up the implementation design and have that
>>>>>>> come with this proof of concept code . This will let us know what choices
>>>>>>> it makes, why it makes them, and we can determine if these are the right
>>>>>>> choices together.
>>>>>>>
>>>>>>> On Wed, Jun 17, 2020 at 4:57 PM Brian Bouterse <bmbouter at redhat.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> I got a lot further on this today. I have the test ldap setup with
>>>>>>>> several test users and groups. I have django-auth-ldap configured mostly
>>>>>>>> authenticating username/password against ldap instead of the internal
>>>>>>>> database first. Once that is fully working the users will auto-populate
>>>>>>>> into django and the groups should follow easily.
>>>>>>>>
>>>>>>>> Once that's done I'll be unblocked to finish the RBAC PoC. The rest
>>>>>>>> of the parts are straightforward given the testing I've already done. More
>>>>>>>> updates to come.
>>>>>>>>
>>>>>>>> On Mon, Jun 15, 2020 at 5:03 PM Brian Bouterse <bmbouter at redhat.com>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>> I got the ldap reference implementation performing auth really
>>>>>>>>> nicely against a test ldap with this guide:
>>>>>>>>> https://www.nginx.com/blog/nginx-plus-authenticate-users/ Now
>>>>>>>>> there are some new challenges though:
>>>>>>>>>
>>>>>>>>> * Great that we can auth users, but we need nginx to
>>>>>>>>> extract-and-forward the group information to Pulp itself. That way a
>>>>>>>>> middleware can create the user AND group info in the backend.
>>>>>>>>> * we have to figure this out all again in Apache...
>>>>>>>>>
>>>>>>>>> Maybe we should be integrating Pulp directly against
>>>>>>>>> django-auth-ldap [0]. I am going to try that next. The work I've done isn't
>>>>>>>>> 100% reusable there, but most of it is because the test server and configs
>>>>>>>>> I used can all be reused directly with django-auth-ldap. The concern with
>>>>>>>>> this approach is that we would be supporting LDAP (and transitively Active
>>>>>>>>> Directory) but are there other directory services Pulp needs to support?
>>>>>>>>>
>>>>>>>>> I also emailed Bin Li asking for info on how their user and group
>>>>>>>>> management works.
>>>>>>>>>
>>>>>>>>> On Tue, Jun 9, 2020 at 11:48 AM Adrian Likins <alikins at redhat.com>
>>>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> On Fri, Jun 5, 2020 at 8:23 PM Brian Bouterse <
>>>>>>>>>> bmbouter at redhat.com> wrote:
>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> 1) django admin (the built in django UI) will be the mechanism
>>>>>>>>>>> administrators use to assign permissions to users and groups. This means
>>>>>>>>>>> the use of django admin with pulp is very likely (to me).
>>>>>>>>>>>
>>>>>>>>>>> Hopefully https://github.com/pulp/pulpcore/pull/705 will be
>>>>>>>>>> useful here.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>> 2) externally defined users and groups will need to be
>>>>>>>>>>> "replicated" to django's db at login time, probably using headers from the
>>>>>>>>>>> webserver This is consistent w/ the approach recommended here:
>>>>>>>>>>> https://www.adelton.com/django/external-authentication-for-django-projects
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> This is more or less what galaxy_ng ends up doing, at least for
>>>>>>>>>> the scenarios where it runs hosted with external SSO.
>>>>>>>>>>
>>>>>>>>>> https://github.com/ansible/galaxy_ng/blob/master/galaxy_ng/app/auth/auth.py#L51 for
>>>>>>>>>> example.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://listman.redhat.com/archives/pulp-dev/attachments/20200701/6a4bdd0e/attachment.htm>