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: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/emc6w201.c b/drivers/hwmon/emc6w201.c
index f37fe2011640c44f2fb4a285da5196b8e79b9be8..4aee5adf9ef2501abb32700e6f92c2fce2c05b7b 100644 (file)
--- a/drivers/hwmon/emc6w201.c
+++ b/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);