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>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/hwmon/emc6w201.c b/drivers/hwmon/emc6w201.c
index f37fe2011640..4aee5adf9ef2 100644
--- 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);