Messages in this thread | | | Date | Fri, 7 Jan 2011 20:35:47 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH] Read THREAD_CPUTIME clock from other processes. |
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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.
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