Re: [tip: timers/urgent] posix-cpu-timers: Prevent UAF caused by non-leader exec() race

[Oleg Nesterov]

On 07/08, Frederic Weisbecker wrote:
>
> > There is a similar problem vs. posix_cpu_timer_set(). For regular posix
> > timers it just transiently returns -ESRCH to user space, but for the use
> > case in do_cpu_nanosleep() it's the same UAF just that the k_itimer is
> > allocated on the stack.
>
> do_cpu_nanosleep() only targets current and since it's on the stack, no
> other task can access it. And the current task can't be exiting/exec'ing
> while calling posix_cpu_timer_set() on that stack timer.

I thought the same initially, but it seems that this is not true...

I can never understand this API, but it seems that
sys_clock_nanosleep() can target the !current processes/threads ?

Or why else we have clock_getcpuclockid() ?

Oleg.