Commit d3d89c46 authored by Doug Anderson's avatar Doug Anderson Committed by Guenter Roeck

hwmon: (ntc_thermistor) Avoid math overflow

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: default avatarDoug Anderson <dianders@chromium.org>
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent b28a960c
...@@ -145,7 +145,7 @@ struct ntc_data { ...@@ -145,7 +145,7 @@ struct ntc_data {
static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata) static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata)
{ {
struct iio_channel *channel = pdata->chan; struct iio_channel *channel = pdata->chan;
unsigned int result; s64 result;
int val, ret; int val, ret;
ret = iio_read_channel_raw(channel, &val); ret = iio_read_channel_raw(channel, &val);
...@@ -155,10 +155,10 @@ static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata) ...@@ -155,10 +155,10 @@ static int ntc_adc_iio_read(struct ntc_thermistor_platform_data *pdata)
} }
/* unit: mV */ /* unit: mV */
result = pdata->pullup_uv * val; result = pdata->pullup_uv * (s64) val;
result >>= 12; result >>= 12;
return result; return (int)result;
} }
static const struct of_device_id ntc_match[] = { static const struct of_device_id ntc_match[] = {
......
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