Commit 4077b7e3 authored by Alexandre Belloni's avatar Alexandre Belloni Committed by Khalid Elmously

rtc: hctosys: Ensure system time doesn't overflow time_t

BugLink: https://bugs.launchpad.net/bugs/1775771

[ Upstream commit b3a5ac42 ]

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: default avatarArnd Bergmann <arnd@arndb.de>
Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: default avatarSasha Levin <alexander.levin@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarJuerg Haefliger <juergh@canonical.com>
Signed-off-by: default avatarKhalid Elmously <khalid.elmously@canonical.com>
parent 778ffd75
......@@ -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,
......
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