From dd6b3e0a66592a72914be1d38ba29f93804e3161 Mon Sep 17 00:00:00 2001 From: Alexandre Belloni Date: Thu, 8 Mar 2018 23:27:31 +0100 Subject: [PATCH] rtc: hctosys: Ensure system time doesn't overflow time_t [ Upstream commit b3a5ac42ab18b7d1a8f2f072ca0ee76a3b754a43 ] On 32bit platforms, time_t is still a signed 32bit long. If it is overflowed, userspace and the kernel cant agree on the current system time. This causes multiple issues, in particular with systemd: https://github.com/systemd/systemd/issues/1143 A good workaround is to simply avoid using hctosys which is something I greatly encourage as the time is better set by userspace. However, many distribution enable it and use systemd which is rendering the system unusable in case the RTC holds a date after 2038 (and more so after 2106). Many drivers have workaround for this case and they should be eliminated so there is only one place left to fix when userspace is able to cope with dates after the 31bit overflow. Acked-by: Arnd Bergmann Signed-off-by: Alexandre Belloni Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/rtc/hctosys.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/rtc/hctosys.c b/drivers/rtc/hctosys.c index e1cfa06..e79f2a1 100644 --- a/drivers/rtc/hctosys.c +++ b/drivers/rtc/hctosys.c @@ -49,6 +49,11 @@ static int __init rtc_hctosys(void) tv64.tv_sec = rtc_tm_to_time64(&tm); +#if BITS_PER_LONG == 32 + if (tv64.tv_sec > INT_MAX) + goto err_read; +#endif + err = do_settimeofday64(&tv64); dev_info(rtc->dev.parent, -- 2.7.4