[Pulp-dev] RBAC Status Thread

Tue Jun 30 21:08:18 UTC 2020

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.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>
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