Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932855AbaBUM4Q (ORCPT ); Fri, 21 Feb 2014 07:56:16 -0500 Received: from youngberry.canonical.com ([91.189.89.112]:47289 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932618AbaBUMvn (ORCPT ); Fri, 21 Feb 2014 07:51:43 -0500 From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Doug Anderson , Guenter Roeck , Luis Henriques Subject: [PATCH 3.11 110/121] hwmon: (ntc_thermistor) Avoid math overflow Date: Fri, 21 Feb 2014 12:48:54 +0000 Message-Id: <1392986945-9693-111-git-send-email-luis.henriques@canonical.com> X-Mailer: git-send-email 1.9.0 In-Reply-To: <1392986945-9693-1-git-send-email-luis.henriques@canonical.com> References: <1392986945-9693-1-git-send-email-luis.henriques@canonical.com> X-Extended-Stable: 3.11 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.11.10.5 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Doug Anderson commit d3d89c468ceebbcf9423d1a3d66c5bf91f569570 upstream. The ntc thermistor code was doing math whose temporary result might have overflowed 32-bits. We need some casts in there to make it safe. In one example I found: - pullup_uV: 1800000 - result of iio_read_channel_raw: 3226 - 1800000 * 3226 => 0x15a1cbc80 Signed-off-by: Doug Anderson Signed-off-by: Guenter Roeck Signed-off-by: Luis Henriques --- drivers/hwmon/ntc_thermistor.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/hwmon/ntc_thermistor.c b/drivers/hwmon/ntc_thermistor.c index 830a842..4a80a54 100644 --- a/drivers/hwmon/ntc_thermistor.c +++ b/drivers/hwmon/ntc_thermistor.c @@ -145,7 +145,7 @@ struct ntc_data { static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata) { struct iio_channel *channel = pdata->chan; - unsigned int result; + s64 result; int val, ret; ret = iio_read_channel_raw(channel, &val); @@ -155,10 +155,10 @@ static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata) } /* unit: mV */ - result = pdata->pullup_uv * val; + result = pdata->pullup_uv * (s64) val; result >>= 12; - return result; + return (int)result; } static const struct of_device_id ntc_match[] = { -- 1.9.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/