hwmon: (emcw201) Fix overflows seen when writing into limit attributes

Writes into temperature and voltage limit attributes can overflow
due to multiplications with unchecked parameters. Also, the input
parameter to DIV_ROUND_CLOSEST() needis to be range checked.
Reviewed-by: NJean Delvare <jdelvare@suse.de>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

drivers/hwmon/emc6w201.c

@@ -215,12 +215,13 @@ static ssize_t set_in(struct device *dev, struct device_attribute *devattr,
 	if (err < 0)
 		return err;
 
-	val = DIV_ROUND_CLOSEST(val * 0xC0, nominal_mv[nr]);
+	val = clamp_val(val, 0, 255 * nominal_mv[nr] / 192);
+	val = DIV_ROUND_CLOSEST(val * 192, nominal_mv[nr]);
 	reg = (sf == min) ? EMC6W201_REG_IN_LOW(nr)
 			  : EMC6W201_REG_IN_HIGH(nr);
 
 	mutex_lock(&data->update_lock);
-	data->in[sf][nr] = clamp_val(val, 0, 255);
+	data->in[sf][nr] = val;
 	err = emc6w201_write8(client, reg, data->in[sf][nr]);
 	mutex_unlock(&data->update_lock);
 
@@ -252,12 +253,13 @@ static ssize_t set_temp(struct device *dev, struct device_attribute *devattr,
 	if (err < 0)
 		return err;
 
+	val = clamp_val(val, -127000, 127000);
 	val = DIV_ROUND_CLOSEST(val, 1000);
 	reg = (sf == min) ? EMC6W201_REG_TEMP_LOW(nr)
 			  : EMC6W201_REG_TEMP_HIGH(nr);
 
 	mutex_lock(&data->update_lock);
-	data->temp[sf][nr] = clamp_val(val, -127, 127);
+	data->temp[sf][nr] = val;
 	err = emc6w201_write8(client, reg, data->temp[sf][nr]);
 	mutex_unlock(&data->update_lock);