Re: Django user system and permissions

[Bob Cochran <yocto@mindchasers.com>]

On 05/29/2014 01:46 PM, Wymore, Farrell wrote:
> Hi Bob,
>
> First, none of this is cast in stone. I did an initial investigation a few weeks ago
> and created a prototype implementation. This feature is still very much under
> discussion.
>
> To elaborate a little on Belen's comments:


Thank you Farrell, Belen, and Alex for the thorough replies.  I'll 
follow up later to some of the questions you posed after I become more 
familiar with Toaster on 1.6.

Regarding permissions, the Linux model, and a user getting access to a 
shell, it may be prudent to not implement a second set of permissions 
and just rely on (query) the OS each time the user makes a request of 
Toaster.  Each link could trigger a Javascript function that queries the 
Python server and the server in turn could query the OS for whether the 
user has permissions (from the OS) to execute the link / task.  Of 
course, the server would tailor the links shown on the Toaster web page 
based on the permissions granted by the OS (administrator).

This way the permissions would remain consistent if the user switched 
back & forth between Toaster and a shell.  My fear is that if you have 
two sets of permissions, it will create confusion and access control 
holes for this class of user (such as myself).

Thanks again,

Bob




>
> -----Original Message-----
> From: Barros Pena, Belen [mailto:belen.barros.pena@intel.com]
> Sent: Thursday, May 29, 2014 2:54 AM
> To: Bob Cochran; Wymore, Farrell; DAMIAN, ALEXANDRU; Reyna, David; toaster@yoctoproject.org
> Subject: Re: [Toaster] Django user system and permissions
>
> On 29/05/2014 03:59, "Bob Cochran" <yocto@mindchasers.com> wrote:
>
>>> On 05/28/2014 04:35 PM, Wymore, Farrell wrote:
>>>> I¹ve attached a (short) working paper. This is fairly high level but
>>>> outlines the main ideas and
>>>>
>>>> implementation plan. Everywhere the documents indicates a Œbuild¹,
>>>> substitute Œproject¹. Please
>>>>
>>>> let me know what you think. Thanks.
>>>>
>>>
>>>
>>> Hi Farrell,
>
>> Hi Bob,
>
>> The answers to your questions are... well, that we don't have answers yet
>> :) Just to clarify: access control and permissions are not a key deliverable for the 1.7 release. We'll make them happen if we can, subject to the priority work being done. Some more details below.
>
> This is a feature Wind River will  need (likely sooner than later).
> In the current prototype implementation, this feature can be turned off easily.
>
>>>
>>> I have a few questions about your document & Toaster in general:
>>>
>>> Will the Toaster permissions correspond in any way to the actual build
>>> folders, or is this just permissions to access specific web pages and
>>> links (e.g., start build)?
>
> No. It is not the intention to mirror the host filesystem permissions. Rather the permissions are applied to database objects.
> In the current prototype implementation, the permissions are applied to a build object. Permissions can be set such that one
> user can see and manipulate a build while others cannot.
>
> Sometime in the future permissions will likely be applied to projects, as Belen indicates below, rather than a single build.
>
>> Personally, I'd like to see permissions based on projects. Projects are coming on the 1.7 release. A project will be a specific configuration you can build against, making changes to it as needed of >course (you might want to change the value of a variable or add a layer or what not). If you have a configuration that you know a few people will need to build against, you give them "build access" to >that project. If you want them to be able to change the configuration, you give them "edit" (or write) access. If you just want them to download the outcome of the builds (a rootfs), you give them >"download" (or read) access.
>
>> I think the Linux file system is very sophisticated, probably a bit too much for a first implementation of access control in a web application.
>> Also, we might find we need different types of permissions other than read and write. But everything is still very much in the air: we are still discussing how to do this.
>
> The linux/unix filesystem is sophisticated but is also one of the simpler models. For Toaster, this model accomplishes 2 key things:
> 1) excludes users from builds they should not see/have access to, 2) allows a user to share a build with others.
>
>>>
>>> A related question: Is the idea that a toaster user will never grab a
>>> shell?
>
> This would depend on a specific deployment. From a WindRiver point-of-view the answer is NO.
>
>> That is an interesting question. I don't think the idea is to prevent people from grabbing a shell: it's about providing alternatives to the shell.
>
>>>
>>> If a user has basic permissions, can a user create a new image recipe,
>>> work directory, and bbappend files to create their own customized image?
>
>> See above: there might be different kinds of permissions, and permissions could be allocated for a specific configuration (i.e. a project).
> Belen's comment is spot on.
>
>>>
>>>   If so, will the permission model also support the amount of storage
>>> available to the user?
>>> You¹ll probably want to prevent a user from creating an infinite number
>>> of new projects until the disks are exhausted.
>
>> This is a very good point: when we design the permissions system, we should keep this in mind.
>
> I'm sure we'll need to impose limits of some kind (or charge real money). We haven't explored this
> question.
>
>>>
>>> Why is the Django admin application not supported in Toaster?
>
> I did investigate the Django admin. There are parts that can be used and is part of the prototype
> implementation. The Django admin is good for managing users and authenticating credentials.
> Django also has capabilities which can be grouped together (called 'groups' in django) and assigned
> to an object. This is not the same concept as the linux groups which represents one or more users.
> Further, we want to assign permissions to a build/project and check this permission against some
> credential. This is something Django does not do.
>
>> Alex will need to answer this one.
>
>>> I just
>>> started using Toaster (but am a long time user of Django).  For local
>>> server use, I'll want to patch in the admin app.
>>>
>>> Lastly, Upon initial review & use, Toaster seems awesome!
>>>
>>> Thank you,
>>>
>>> Bob Cochran
>>>
>>>
>>>
>>>
>>>
>>>
>>>
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>
>
>