Re: [PATCH] time: fix a assignment error in ntp module

[Thomas Gleixner]

Miroslav,

On Mon, 17 Jun 2019, Miroslav Lichvar wrote:

> On Mon, Jun 17, 2019 at 02:14:57PM +0200, Thomas Gleixner wrote:
> > On Mon, 17 Jun 2019, çåç wrote:
> > > Yes,the  >UINT_MAX value can be passed by
> > > syscall adjtimex->do_adjtimex->__do_adjtimex->process_adjtimex_modes by the
> > > proper arugments.
> > 
> > So there is clearly some sanity check missing, but surely not that
> > type cast.
> 
> As the offset is saved in an int (and returned via adjtimex() in the
> tai field), should be the maximum INT_MAX?

Right.

> We probably also want to avoid overflow in the offset on a leap second
> and the CLOCK_TAI clock itself, so maybe it would make sense to
> specify a much smaller maximum like 1000000?
> 
> Even 1000 should be good enough for near future. Negative values are
> not allowed anyway. If the Earth's rotation changed significantly
> (e.g. hitting a very large asteroid), there probably wouldn't be
> anyone left to care about TAI. 

Hehehe. I leave it to you to find a sane limit taking all the possible
events into account :)

Thanks,

	tglx