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

From	Sasha Levin <sasha.levin@oracle.com>
Newsgroups	linux.kernel
Subject	[PATCH] rtc: fix overflow and incorrect calculation in rtc_time64_to_tm
Date	2015-12-04 01:20 +0100
Message-ID	<qBMgp-3Ms-7@gated-at.bofh.it> (permalink)
Organization	linux.* mail to news gateway

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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@oracle.com>
---
 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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[PATCH] rtc: fix overflow and incorrect calculation in rtc_time64_to_tm Sasha Levin <sasha.levin@oracle.com> - 2015-12-04 01:20 +0100
  Re: [PATCH] rtc: fix overflow and incorrect calculation in  rtc_time64_to_tm kbuild test robot <lkp@intel.com> - 2015-12-04 01:30 +0100
  Re: [PATCH] rtc: fix overflow and incorrect calculation in  rtc_time64_to_tm kbuild test robot <lkp@intel.com> - 2015-12-04 02:50 +0100
  Re: [PATCH] rtc: fix overflow and incorrect calculation in  rtc_time64_to_tm kbuild test robot <lkp@intel.com> - 2015-12-04 02:50 +0100
  Re: [PATCH] rtc: fix overflow and incorrect calculation in  rtc_time64_to_tm Alexandre Belloni <alexandre.belloni@free-electrons.com> - 2015-12-04 03:00 +0100
    Re: [PATCH] rtc: fix overflow and incorrect calculation in  rtc_time64_to_tm Sasha Levin <sasha.levin@oracle.com> - 2015-12-04 03:10 +0100

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