Linux PWM subsystem development
 help / color / mirror / Atom feed
* [PATCH AUTOSEL 4.19] pwm: Fix double shift bug
@ 2023-11-15  3:42 Sasha Levin
  0 siblings, 0 replies; only message in thread
From: Sasha Levin @ 2023-11-15  3:42 UTC (permalink / raw)
  To: linux-kernel, stable
  Cc: Dan Carpenter, Uwe Kleine-König, Sam Protsenko,
	Thierry Reding, Sasha Levin, linux-pwm

From: Dan Carpenter <dan.carpenter@linaro.org>

[ Upstream commit d27abbfd4888d79dd24baf50e774631046ac4732 ]

These enums are passed to set/test_bit().  The set/test_bit() functions
take a bit number instead of a shifted value.  Passing a shifted value
is a double shift bug like doing BIT(BIT(1)).  The double shift bug
doesn't cause a problem here because we are only checking 0 and 1 but
if the value was 5 or above then it can lead to a buffer overflow.

Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 include/linux/pwm.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index bd7d611d63e91..c6e981035c3fd 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -44,8 +44,8 @@ struct pwm_args {
 };
 
 enum {
-	PWMF_REQUESTED = 1 << 0,
-	PWMF_EXPORTED = 1 << 1,
+	PWMF_REQUESTED = 0,
+	PWMF_EXPORTED = 1,
 };
 
 /*
-- 
2.42.0


^ permalink raw reply related	[flat|nested] only message in thread

only message in thread, other threads:[~2023-11-15  3:43 UTC | newest]

Thread overview: (only message) (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-11-15  3:42 [PATCH AUTOSEL 4.19] pwm: Fix double shift bug Sasha Levin

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox