adt7470: check input range when sysfs files are written

Implement correct range checking for adt7470 to prevent userland from
writing impossible values into the chip, and cap out-of-range values per
standard hwmon conventions.

Implement correct rounding of input values per standard hwmon conventions.

Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 62 insertions, 13 deletions

diff --git a/drivers/hwmon/adt7470.c b/drivers/hwmon/adt7470.c
index d368d8f845e1..1311a595147e 100644
--- a/drivers/hwmon/adt7470.c
+++ b/drivers/hwmon/adt7470.c
@@ -137,6 +137,8 @@ I2C_CLIENT_INSMOD_1(adt7470);
 #define FAN_PERIOD_INVALID      65535
 #define FAN_DATA_VALID(x)       ((x) && (x) != FAN_PERIOD_INVALID)
 
+#define ROUND_DIV(x, divisor)   (((x) + ((divisor) / 2)) / (divisor))
+
 struct adt7470_data {
         struct device           *hwmon_dev;
         struct attribute_group  attrs;
@@ -353,7 +355,13 @@ static ssize_t set_temp_min(struct device *dev,
         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
         struct i2c_client *client = to_i2c_client(dev);
         struct adt7470_data *data = i2c_get_clientdata(client);
-        int temp = simple_strtol(buf, NULL, 10) / 1000;
+        long temp;
+
+        if (strict_strtol(buf, 10, &temp))
+                return -EINVAL;
+
+        temp = ROUND_DIV(temp, 1000);
+        temp = SENSORS_LIMIT(temp, 0, 255);
 
         mutex_lock(&data->lock);
         data->temp_min[attr->index] = temp;
@@ -381,7 +389,13 @@ static ssize_t set_temp_max(struct device *dev,
         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
         struct i2c_client *client = to_i2c_client(dev);
         struct adt7470_data *data = i2c_get_clientdata(client);
-        int temp = simple_strtol(buf, NULL, 10) / 1000;
+        long temp;
+
+        if (strict_strtol(buf, 10, &temp))
+                return -EINVAL;
+
+        temp = ROUND_DIV(temp, 1000);
+        temp = SENSORS_LIMIT(temp, 0, 255);
 
         mutex_lock(&data->lock);
         data->temp_max[attr->index] = temp;
@@ -430,11 +444,13 @@ static ssize_t set_fan_max(struct device *dev,
         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
         struct i2c_client *client = to_i2c_client(dev);
         struct adt7470_data *data = i2c_get_clientdata(client);
-        int temp = simple_strtol(buf, NULL, 10);
+        long temp;
 
-        if (!temp)
+        if (strict_strtol(buf, 10, &temp) || !temp)
                 return -EINVAL;
+
         temp = FAN_RPM_TO_PERIOD(temp);
+        temp = SENSORS_LIMIT(temp, 1, 65534);
 
         mutex_lock(&data->lock);
         data->fan_max[attr->index] = temp;
@@ -465,11 +481,13 @@ static ssize_t set_fan_min(struct device *dev,
         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
         struct i2c_client *client = to_i2c_client(dev);
         struct adt7470_data *data = i2c_get_clientdata(client);
-        int temp = simple_strtol(buf, NULL, 10);
+        long temp;
 
-        if (!temp)
+        if (strict_strtol(buf, 10, &temp) || !temp)
                 return -EINVAL;
+
         temp = FAN_RPM_TO_PERIOD(temp);
+        temp = SENSORS_LIMIT(temp, 1, 65534);
 
         mutex_lock(&data->lock);
         data->fan_min[attr->index] = temp;
@@ -507,9 +525,12 @@ static ssize_t set_force_pwm_max(struct device *dev,
 {
         struct i2c_client *client = to_i2c_client(dev);
         struct adt7470_data *data = i2c_get_clientdata(client);
-        int temp = simple_strtol(buf, NULL, 10);
+        long temp;
         u8 reg;
 
+        if (strict_strtol(buf, 10, &temp))
+                return -EINVAL;
+
         mutex_lock(&data->lock);
         data->force_pwm_max = temp;
         reg = i2c_smbus_read_byte_data(client, ADT7470_REG_CFG);
@@ -537,7 +558,12 @@ static ssize_t set_pwm(struct device *dev, struct device_attribute *devattr,
         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
         struct i2c_client *client = to_i2c_client(dev);
         struct adt7470_data *data = i2c_get_clientdata(client);
-        int temp = simple_strtol(buf, NULL, 10);
+        long temp;
+
+        if (strict_strtol(buf, 10, &temp))
+                return -EINVAL;
+
+        temp = SENSORS_LIMIT(temp, 0, 255);
 
         mutex_lock(&data->lock);
         data->pwm[attr->index] = temp;
@@ -564,7 +590,12 @@ static ssize_t set_pwm_max(struct device *dev,
         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
         struct i2c_client *client = to_i2c_client(dev);
         struct adt7470_data *data = i2c_get_clientdata(client);
-        int temp = simple_strtol(buf, NULL, 10);
+        long temp;
+
+        if (strict_strtol(buf, 10, &temp))
+                return -EINVAL;
+
+        temp = SENSORS_LIMIT(temp, 0, 255);
 
         mutex_lock(&data->lock);
         data->pwm_max[attr->index] = temp;
@@ -592,7 +623,12 @@ static ssize_t set_pwm_min(struct device *dev,
         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
         struct i2c_client *client = to_i2c_client(dev);
         struct adt7470_data *data = i2c_get_clientdata(client);
-        int temp = simple_strtol(buf, NULL, 10);
+        long temp;
+
+        if (strict_strtol(buf, 10, &temp))
+                return -EINVAL;
+
+        temp = SENSORS_LIMIT(temp, 0, 255);
 
         mutex_lock(&data->lock);
         data->pwm_min[attr->index] = temp;
@@ -630,7 +666,13 @@ static ssize_t set_pwm_tmin(struct device *dev,
         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
         struct i2c_client *client = to_i2c_client(dev);
         struct adt7470_data *data = i2c_get_clientdata(client);
-        int temp = simple_strtol(buf, NULL, 10) / 1000;
+        long temp;
+
+        if (strict_strtol(buf, 10, &temp))
+                return -EINVAL;
+
+        temp = ROUND_DIV(temp, 1000);
+        temp = SENSORS_LIMIT(temp, 0, 255);
 
         mutex_lock(&data->lock);
         data->pwm_tmin[attr->index] = temp;
@@ -658,11 +700,14 @@ static ssize_t set_pwm_auto(struct device *dev,
         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
         struct i2c_client *client = to_i2c_client(dev);
         struct adt7470_data *data = i2c_get_clientdata(client);
-        int temp = simple_strtol(buf, NULL, 10);
         int pwm_auto_reg = ADT7470_REG_PWM_CFG(attr->index);
         int pwm_auto_reg_mask;
+        long temp;
         u8 reg;
 
+        if (strict_strtol(buf, 10, &temp))
+                return -EINVAL;
+
         if (attr->index % 2)
                 pwm_auto_reg_mask = ADT7470_PWM2_AUTO_MASK;
         else
@@ -716,10 +761,14 @@ static ssize_t set_pwm_auto_temp(struct device *dev,
         struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
         struct i2c_client *client = to_i2c_client(dev);
         struct adt7470_data *data = i2c_get_clientdata(client);
-        int temp = cvt_auto_temp(simple_strtol(buf, NULL, 10));
         int pwm_auto_reg = ADT7470_REG_PWM_AUTO_TEMP(attr->index);
+        long temp;
         u8 reg;
 
+        if (strict_strtol(buf, 10, &temp))
+                return -EINVAL;
+
+        temp = cvt_auto_temp(temp);
         if (temp < 0)
                 return temp;