On Tue, Mar 05, 2019 at 05:42:25PM -0800, John Stultz wrote: > > --- a/kernel/time/ntp.c > > +++ b/kernel/time/ntp.c > > @@ -677,6 +677,8 @@ static inline void process_adjtimex_modes(const struct > > timex *txc, s32 *time_tai > > > > if (txc->modes & ADJ_MAXERROR) > > time_maxerror = txc->maxerror; > > + if (time_maxerror > NTP_PHASE_LIMIT) > > + time_maxerror = NTP_PHASE_LIMIT; > > This looks sane to me. > Acked-by: John Stultz <john.stu...@linaro.org> > > Though it makes me wonder a bit more about the sanity checking on the > other parameters passed via adjtimex(), tick_usec for instance looks > like it could be similarly problematic.
The tick length is checked earlier in timekeeping_validate_timex(), so that should be ok. What I'd like to see clamped is the system time itself. ktime_t overflows on Apr 11 2262. clock_settime() and adjtimex(ADJ_SETOFFSET) can set the time close to the overflow and let everything break. Boot a VM and try this: # date -s 'Apr 11 23:47:15 UTC 2262' There was a patch submitted couple years ago that prevented overflows in 32-bit time_t and ktime_t. http://lkml.iu.edu/hypermail/linux/kernel/1510.0/04719.html -- Miroslav Lichvar
