Messages in this thread | | | Date | Mon, 23 Sep 2019 15:39:06 +0200 | From | Frederic Weisbecker <> | Subject | Re: [patch 4/6] posix-cpu-timers: Restrict clock_gettime() permissions |
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On Thu, Sep 05, 2019 at 02:03:43PM +0200, Thomas Gleixner wrote: > Similar to creating timers on a process there is no restriction at all to > read the Posix CPU clocks of any process in the system. Per thread CPU > clock access is limited to threads in the same thread group. > > The per process CPU clocks can be used to observe activity of tasks and > reading them can affect the execution of the process to which they are > attached as reading can require to lock sighand lock and sum up the fine > grained accounting for all threads in the process. > > Restrict it by checking ptrace MODE_READ permissions of the reader on the > target process. > > Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
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