From: Dmitry Torokhov Date: Tue, 28 Oct 2014 16:27:58 +0000 (-0700) Subject: Input: max77693-haptic - fix potential overflow X-Git-Tag: v3.18-rc3~11^2~3 X-Git-Url: http://git.cascardo.info/?p=cascardo%2Flinux.git;a=commitdiff_plain;h=fbefc5e7e63228d56963eeb0db10209ea0fafe9d Input: max77693-haptic - fix potential overflow Expression haptic->pwm_dev->period * haptic->magnitude is of type 'unsigned int' and may overflow. We need to convert one of the operands to u64 before multiplying, instead of casting result (potentially overflown) to u64. Reported by Coverity: CID 1248753 Acked-by : Jaewon Kim Reviewed-by: Chanwoo Choi Signed-off-by: Dmitry Torokhov --- diff --git a/drivers/input/misc/max77693-haptic.c b/drivers/input/misc/max77693-haptic.c index 7b1fde93799e..ef6a9d650d69 100644 --- a/drivers/input/misc/max77693-haptic.c +++ b/drivers/input/misc/max77693-haptic.c @@ -194,7 +194,7 @@ static int max77693_haptic_play_effect(struct input_dev *dev, void *data, struct ff_effect *effect) { struct max77693_haptic *haptic = input_get_drvdata(dev); - uint64_t period_mag_multi; + u64 period_mag_multi; haptic->magnitude = effect->u.rumble.strong_magnitude; if (!haptic->magnitude) @@ -205,8 +205,7 @@ static int max77693_haptic_play_effect(struct input_dev *dev, void *data, * The formula to convert magnitude to pwm_duty as follows: * - pwm_duty = (magnitude * pwm_period) / MAX_MAGNITUDE(0xFFFF) */ - period_mag_multi = (int64_t)(haptic->pwm_dev->period * - haptic->magnitude); + period_mag_multi = (u64)haptic->pwm_dev->period * haptic->magnitude; haptic->pwm_duty = (unsigned int)(period_mag_multi >> MAX_MAGNITUDE_SHIFT);