From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752562AbaJ1Qn3 (ORCPT ); Tue, 28 Oct 2014 12:43:29 -0400 Received: from mail-pd0-f172.google.com ([209.85.192.172]:37415 "EHLO mail-pd0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750855AbaJ1Qn1 (ORCPT ); Tue, 28 Oct 2014 12:43:27 -0400 Date: Tue, 28 Oct 2014 09:43:22 -0700 From: Dmitry Torokhov To: linux-input@vger.kernel.org Cc: Chanwoo Choi , Jaewon Kim , linux-kernel@vger.kernel.org Subject: [PATCH] Input: max77693-haptic - fix potential overflow Message-ID: <20141028164322.GA13234@dtor-ws> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Signed-off-by: Dmitry Torokhov --- drivers/input/misc/max77693-haptic.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/input/misc/max77693-haptic.c b/drivers/input/misc/max77693-haptic.c index 7b1fde9..ef6a9d6 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); -- 2.1.0.rc2.206.gedb03e5 -- Dmitry