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From: Frederic Weisbecker <frederic@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Oleg Nesterov <oleg@redhat.com>, Ingo Molnar <mingo@kernel.org>,
	Kees Cook <keescook@chromium.org>
Subject: Re: [patch 3/6] posix-cpu-timers: Restrict timer_create() permissions
Date: Sat, 21 Sep 2019 02:44:46 +0200	[thread overview]
Message-ID: <20190921004445.GB6449@lenoir> (raw)
In-Reply-To: <20190905120539.888798188@linutronix.de>

On Thu, Sep 05, 2019 at 02:03:42PM +0200, Thomas Gleixner wrote:
> Right now there is no restriction at all to attach a Posix CPU timer to any
> process in the system. Per thread CPU timers are limited to be created by
> threads in the same thread group.
> 
> Timers can be used to observe activity of tasks and also impose overhead on
> the process to which they are attached because that process needs to do the
> fine grained CPU time accounting.
> 
> Limit the ability to attach timers to a process by checking whether the
> task which is creating the timer has permissions to attach ptrace on the
> target process.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Makes sense. I hope no serious user currently rely on that lack of
restriction. Let's just apply and wait for complains if any.

Reviewed-by: Frederic Weisbecker <frederic@kernel.org>

  reply	other threads:[~2019-09-21  0:44 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-05 12:03 [patch 0/6] posix-cpu-timers: Fallout fixes and permission tightening Thomas Gleixner
2019-09-05 12:03 ` [patch 1/6] posix-cpu-timers: Always clear head pointer on dequeue Thomas Gleixner
2019-09-05 15:49   ` Frederic Weisbecker
2019-09-05 12:03 ` [patch 2/6] posix-cpu-timers: Fix permission check regression Thomas Gleixner
2019-09-05 17:31   ` Frederic Weisbecker
2019-09-05 18:55     ` Thomas Gleixner
2019-09-05 21:15       ` [patch V2 " Thomas Gleixner
2019-09-09 15:13         ` Frederic Weisbecker
2019-09-10 11:18         ` [tip: timers/core] " tip-bot2 for Thomas Gleixner
2019-09-05 12:03 ` [patch 3/6] posix-cpu-timers: Restrict timer_create() permissions Thomas Gleixner
2019-09-21  0:44   ` Frederic Weisbecker [this message]
2019-09-05 12:03 ` [patch 4/6] posix-cpu-timers: Restrict clock_gettime() permissions Thomas Gleixner
2019-09-23 13:39   ` Frederic Weisbecker
2019-09-05 12:03 ` [patch 5/6] posix-cpu-timers: Sanitize thread clock permissions Thomas Gleixner
2019-09-05 12:21   ` Peter Zijlstra
2019-09-05 14:11     ` Thomas Gleixner
2019-09-23 14:03   ` Frederic Weisbecker
2019-09-05 12:03 ` [patch 6/6] posix-cpu-timers: Make PID=0 and PID=self handling consistent Thomas Gleixner
2019-09-23 14:13   ` Frederic Weisbecker
2019-09-23 14:17     ` Thomas Gleixner
2019-09-05 14:48 ` [patch 0/6] posix-cpu-timers: Fallout fixes and permission tightening Frederic Weisbecker
2019-09-05 14:57   ` Thomas Gleixner
2019-09-05 15:21     ` Frederic Weisbecker
2019-09-05 20:32 ` Kees Cook
2019-09-05 21:13   ` Thomas Gleixner

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