Re: [Y2038] [PATCH v6 10/43] compat_ioctl: move rtc handling into rtc-dev.c

[Al Viro]

On Thu, Oct 17, 2019 at 04:33:09PM +0200, Arnd Bergmann wrote:

> However, looking at this again after your comment I found a rather
> more serious bug in my new RTC_IRQP_SET handling: Any 64-bit
> machine can now bypass the permission check for RTC_IRQP_SET by
> calling RTC_IRQP_SET32 instead.

You've lost the check on RTC_EPOCH_SET as well.

Another potential issue is drivers/input/misc/hp_sdc_rtc.c,
provided that the hardware in question might possibly exist
on hppa64 boxen - CONFIG_GSC defaults to y and it's not
32bit-only, so that thing is at least selectable on 64bit
kernels.