Re: [RFC][PATCH 2/2 v3] security: Add task_settimerslack/task_gettimerslack LSM hook

From: John Stultz
Date: Thu Jul 21 2016 - 01:55:12 EST

On Tue, Jul 19, 2016 at 11:12 PM, James Morris <jmorris@xxxxxxxxx> wrote:
> On Mon, 18 Jul 2016, John Stultz wrote:
>> As requested, this patch implements a task_settimerslack and
>> task_gettimerslack LSM hooks so that the /proc/<tid>/timerslack_ns
>> interface can have finer grained security policies applied to it.
>> I've kept the CAP_SYS_NICE check in the timerslack_ns_write/show
>> functions, as hiding it in the LSM hook seems too opaque, and doesn't
>> seem like a widely enough adopted practice.
> I may have missed something in the earlier discussion, but why do we need
> new LSM hooks here vs. calling the existing set/getscheduler hooks?

Mostly since adding a new hook was suggested originally. I don't think
there's much difference as it stands, but I guess more fine grained
checks could be added on the slack amounts, etc.

I can rework it, so let me know if using the existing hooks would be
preferred, but otherwise I'll be sending out the non-rfc patches