tree 90aa85f03539f685e6c38ce09f2a99a72437ab84
parent 3944a4fd0d7015523d55e50fdaa40d12523f2e6a
author Arnd Bergmann <arnd@arndb.de> 1573245268 +0100
committer Pablo Neira Ayuso <pablo@netfilter.org> 1573857885 +0100

netfilter: xt_time: use time64_t

The current xt_time driver suffers from the y2038 overflow on 32-bit
architectures, when the time of day calculations break.

Also, on both 32-bit and 64-bit architectures, there is a problem with
info->date_start/stop, which is part of the user ABI and overflows in
in 2106.

Fix the first issue by using time64_t and explicit calls to div_u64()
and div_u64_rem(), and document the seconds issue.

The explicit 64-bit division is unfortunately slower on 32-bit
architectures, but doing it as unsigned lets us use the optimized
division-through-multiplication path in most configurations.  This should
be fine, as the code already does not allow any negative time of day
values.

Using u32 seconds values consistently would probably also work and
be a little more efficient, but that doesn't feel right as it would
propagate the y2106 overflow to more place rather than fewer.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>