rtc: tps6594: Fix integer overflow on 32bit systems

BugLink: https://bugs.launchpad.net/bugs/2111953

[ 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: 9f67c1e639 ("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>
CVE-2024-57953
Signed-off-by: Manuel Diewald <manuel.diewald@canonical.com>
Signed-off-by: Mehmet Basaran <mehmet.basaran@canonical.com>

This commit is contained in:

Dan Carpenter

2024-12-11 12:32:34 +03:00

committed by

Mehmet Basaran

parent 720e2d191b

commit 16a8f8de77

1 changed files with 1 additions and 1 deletions

									
										drivers/rtc/rtc-tps6594.c
									
		+1
		-1
	
												View File
												
				@@ -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