[PATCH] rtc: fix overflow and incorrect calculation in rtc_time64_to_tm

From: Sasha Levin
Date: Thu Dec 03 2015 - 19:12:50 EST


At some point after humans go extinct and robots cotrol the world, dividing
he time64_t by 86400 to extract the days will overflow a 32bit integer,
leading to incorrect conversion into rtc_time in rtc_time64_to_tm().

Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
drivers/rtc/rtc-lib.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-lib.c b/drivers/rtc/rtc-lib.c
index e6bfb9c..459cd4d 100644
--- a/drivers/rtc/rtc-lib.c
+++ b/drivers/rtc/rtc-lib.c
@@ -54,11 +54,11 @@ void rtc_time64_to_tm(time64_t time, struct rtc_time *tm)
{
unsigned int month, year;
unsigned long secs;
- int days;
+ time64_t days;

/* time must be positive */
days = div_s64(time, 86400);
- secs = time - (unsigned int) days * 86400;
+ secs = time - days * 86400;

/* day of the week, 1970-01-01 was a Thursday */
tm->tm_wday = (days + 4) % 7;
--
1.7.10.4

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