linux-kernel - Re: [PATCH 2/2 v4] proc: Add LSM hook checks to /proc/<tid>/timerslack

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Date:	Wed, 17 Aug 2016 14:36:10 -0700
From:	John Stultz <john.stultz@...aro.org>
To:	Paul Moore <paul@...l-moore.com>
Cc:	lkml <linux-kernel@...r.kernel.org>,
	Kees Cook <keescook@...omium.org>,
	"Serge E. Hallyn" <serge@...lyn.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Arjan van de Ven <arjan@...ux.intel.com>,
	Oren Laadan <orenl@...lrox.com>,
	Ruchi Kandoi <kandoiruchi@...gle.com>,
	Rom Lemarchand <romlem@...roid.com>,
	Todd Kjos <tkjos@...gle.com>, Colin Cross <ccross@...roid.com>,
	Nick Kralevich <nnk@...gle.com>,
	Dmitry Shmidt <dimitrysh@...gle.com>,
	Elliott Hughes <enh@...gle.com>,
	James Morris <jmorris@...ei.org>,
	Android Kernel Team <kernel-team@...roid.com>,
	LSM List <linux-security-module@...r.kernel.org>,
	SELinux <selinux@...ho.nsa.gov>
Subject: Re: [PATCH 2/2 v4] proc: Add LSM hook checks to /proc/<tid>/timerslack_ns

On Wed, Aug 17, 2016 at 2:21 PM, Paul Moore <paul@...l-moore.com> wrote:
> On Thu, Jul 21, 2016 at 4:24 PM, John Stultz <john.stultz@...aro.org> wrote:
>> As requested, this patch checks the existing LSM hooks
>> task_getscheduler/task_setscheduler when reading or modifying
>> the task's timerslack value.
>>
>> Previous versions added new get/settimerslack LSM hooks, but
>> since they checked the same PROCESS__SET/GETSCHED values as
>> existing hooks, it was suggested we just use the existing ones.
>>
>> Cc: Kees Cook <keescook@...omium.org>
>> Cc: "Serge E. Hallyn" <serge@...lyn.com>
>> Cc: Andrew Morton <akpm@...ux-foundation.org>
>> Cc: Thomas Gleixner <tglx@...utronix.de>
>> CC: Arjan van de Ven <arjan@...ux.intel.com>
>> Cc: Oren Laadan <orenl@...lrox.com>
>> Cc: Ruchi Kandoi <kandoiruchi@...gle.com>
>> Cc: Rom Lemarchand <romlem@...roid.com>
>> Cc: Todd Kjos <tkjos@...gle.com>
>> Cc: Colin Cross <ccross@...roid.com>
>> Cc: Nick Kralevich <nnk@...gle.com>
>> Cc: Dmitry Shmidt <dimitrysh@...gle.com>
>> Cc: Elliott Hughes <enh@...gle.com>
>> Cc: James Morris <jmorris@...ei.org>
>> Cc: Android Kernel Team <kernel-team@...roid.com>
>> Cc: linux-security-module@...r.kernel.org
>> Cc: selinux@...ho.nsa.gov
>> Signed-off-by: John Stultz <john.stultz@...aro.org>
>> ---
>> v2:
>>  * Initial swing at adding settimerslack LSM hook
>> v3:
>>  * Fix current/p switchup bug noted by NickK
>>  * Add gettimerslack hook suggested by NickK
>> v4:
>>  * Dropped adding get/settimerslack LSM hooks, and
>>    just reuse the get/setscheduler ones.
>>
>>  fs/proc/base.c | 10 ++++++++++
>>  1 file changed, 10 insertions(+)
>
> For some reason I'm having a hard time finding patch 1/2 in the
> patchset, but this patch looks reasonable to me.  We already have some

https://lkml.org/lkml/2016/7/21/522

> LSM checking via the ptrace_may_access() call, but this adds some
> additional granularity which could be a good thing.
>
> Acked-by: Paul Moore <paul@...l-moore.com>

Thanks. There's also this follow-on patch (and discussion thread) that
adds a fix to the 1/2 patch linked above.

https://lkml.org/lkml/2016/8/9/876

thanks
-john