From: Oleg Nesterov <oleg@redhat.com>
To: Roland McGrath <roland@redhat.com>
Cc: Dario Faggioli <raistlin@linux.it>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel <linux-kernel@vger.kernel.org>,
torbenh <torbenh@gmx.de>,
john.stultz@linaro.org, Ingo Molnar <mingo@elte.hu>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH] Read THREAD_CPUTIME clock from other processes.
Date: Fri, 7 Jan 2011 20:35:47 +0100 [thread overview]
Message-ID: <20110107193547.GA28634@redhat.com> (raw)
In-Reply-To: <20110107192809.05CFF40467@magilla.sf.frob.com>
On 01/07, Roland McGrath wrote:
>
> This can certainly be enhanced, but it opens some cans of worms about the
> security question. It is probably still considered an unsafe information
> leak to let every process examine every other process's thread clocks.
Yes, I was worried about possible security issues too. But, it seems,
/proc/pid/task/tid/stat (do_task_stat) shows ->utime/stime anyway.
And /proc/schedstat shows sum_exec_runtime.
> I'll leave that judgement to security folks.
Agreed.
> As well as the information leak, it is most certainly a DoS attack vector
> to allow one process to set CPU timers an another process or its threads.
No, the suggested change doesn't go that far, afaics. It only modifies
check_clock: this affects clock_getres and clock_set (which does nothing),
and posix_cpu_clock_get: affects clock_gettime().
Oleg.
next prev parent reply other threads:[~2011-01-07 19:43 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-23 16:21 [PATCH] Read THREAD_CPUTIME clock from other processes Dario Faggioli
2010-12-23 16:44 ` Oleg Nesterov
2010-12-23 17:38 ` Dario Faggioli
2010-12-23 18:12 ` Oleg Nesterov
2010-12-24 11:36 ` Dario Faggioli
2010-12-23 17:21 ` Randy Dunlap
2010-12-23 17:43 ` Dario Faggioli
2010-12-28 10:55 ` [PATCH resend] Reading POSIX CPU timer from outside the process Dario Faggioli
2010-12-28 16:38 ` Oleg Nesterov
2010-12-28 21:38 ` Dario Faggioli
2010-12-29 13:21 ` Oleg Nesterov
2010-12-29 14:10 ` Dario Faggioli
2010-12-29 18:30 ` Oleg Nesterov
2010-12-30 17:45 ` torbenh
2011-01-04 11:01 ` Dario Faggioli
2011-01-06 16:06 ` torbenh
2011-01-07 19:28 ` [PATCH] Read THREAD_CPUTIME clock from other processes Roland McGrath
2011-01-07 19:35 ` Oleg Nesterov [this message]
2011-01-07 19:50 ` Roland McGrath
2011-01-07 19:49 ` Oleg Nesterov
2011-01-07 19:58 ` Roland McGrath
2011-01-07 19:56 ` Peter Zijlstra
2011-01-08 11:12 ` Dario Faggioli
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