diff options
| author | Dan Carpenter <dan.carpenter@linaro.org> | 2024-12-11 12:32:34 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-02-08 10:02:08 +0100 |
| commit | 53b0c7b15accb18d15d95c7fe68f61630ebfd1ca (patch) | |
| tree | 8f8af035104bcc26c68c263b47d2ed4059eea926 | |
| parent | 981ad4c882096e7375b8c2181dd4c3ee58ea5bae (diff) | |
rtc: tps6594: Fix integer overflow on 32bit systems
[ Upstream commit 09c4a610153286cef54d4f0c85398f4e32fc227e ]
The problem is this multiply in tps6594_rtc_set_offset()
tmp = offset * TICKS_PER_HOUR;
The "tmp" variable is an s64 but "offset" is a long in the
(-277774)-277774 range. On 32bit systems a long can hold numbers up to
approximately two billion. The number of TICKS_PER_HOUR is really large,
(32768 * 3600) or roughly a hundred million. When you start multiplying
by a hundred million it doesn't take long to overflow the two billion
mark.
Probably the safest way to fix this is to change the type of
TICKS_PER_HOUR to long long because it's such a large number.
Fixes: 9f67c1e63976 ("rtc: tps6594: Add driver for TPS6594 RTC")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/1074175e-5ecb-4e3d-b721-347d794caa90@stanley.mountain
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/rtc/rtc-tps6594.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/rtc/rtc-tps6594.c b/drivers/rtc/rtc-tps6594.c index e69667634137..7c6246e3f029 100644 --- a/drivers/rtc/rtc-tps6594.c +++ b/drivers/rtc/rtc-tps6594.c @@ -37,7 +37,7 @@ #define MAX_OFFSET (277774) // Number of ticks per hour -#define TICKS_PER_HOUR (32768 * 3600) +#define TICKS_PER_HOUR (32768 * 3600LL) // Multiplier for ppb conversions #define PPB_MULT NANO |