On Mon, Feb 26, 2018 at 05:05:04AM +0900, Seunghun Han wrote:
> >> It is a critical security problem because the attacker can make kernel
> >> panic
> >> by writing a value to the check_interval file in userspace, and it can be
> >> used for Denial-of-Service (DoS) attack.
> >
> > As only root can write to that file, it's not that critical of an issue,
> > but yes, this is a problem. Nice find and fix.
This is still the wrong fix. You need to:
1. check the old value of check_interval in store_int_with_restart() and
exit early if it is the same.
2. have mce_restart() grab a newly defined mutex, say, mce_sysfs_mutex
or so, which synchronizes all CPUs so that their timers get deleted and
reinitialized in the proper order.
Thx.
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
