[Dev] Gumd and security-manager integration

Jussi Laako jussi.laako at linux.intel.com
Fri Oct 10 13:45:35 GMT 2014


On 10.10.2014 16:03, Rafał Krypa wrote:
>       * hooks mechanism needs to be enhanced: do post- and pre- hooks,
>         check error codes from scripts

Pre-user-creation and post-user-delete are kind of pointless, because in 
pre-creation-state you don't yet have UID or anything else for the user, 
just username. And in post-user-delete these don't exist anymore.

We can check error codes, but what would we do when there's an error? If 
we would have filesystem that supports snapshots, we could roll back safely.

>  1. Access control
>       * Check whether the user is privileged to perform configuration on
>         other users

We can make group-based access control on this, I'd propose using 
standard "wheel" group for the purpose.

>       * We've got Cynara for such checks, integration scenarios #1 and
>         #2 require gumd to integrate with Cynara

Is it already available and working?

>  2. Smack setup
>       * When a user is created, files in the new home directory needs
>         proper Smack labels

This is already done by gumd. It wouldn't have been possible to 
integrate and verify gumd on Tizen without it.
But you should figure out how to do this correctly with respect to 
/etc/skel as it works already for normal unix DAC permission mask...

>       * When a user is removed, it may require removal of Smack rules
>         for applications installed by that user
>  3. Cynara setup
>       * When a user is removed, we must remove all private Cynara rules
>         for that user

These are suitable for a pre-remove script.

>       * We already implement an offline, deamon-less version of
>         security-manager to be called by root during image creation. Is
>         gumd going to provide such tool as well?

We added support for running the daemon in p2p dbus mode through 
environment variable, so you don't need to have dbus-daemon running. 
This should be enough...

> Taking all of the above into account, I suggest doing the integration
> scenario #3 - wrap gumd in security-manager. This enables best handling
> of Cynara and Smack configuration, keeps related logic inside (i.e. what
> Smack label is assigned to home directory). It also doesn't require and
> Tizen-specific changes to gumd, keeping them in security-manager, which
> is a Tizen-only thing by design.

I think best is to use post-creation script for this purpose. But I can 
live with this approach too as long as it doesn't require Tizen specific 
changes to gumd...



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