[PATCH v2] hwmon: (adt7462) Fix overflows seen when writing into limit attributes

[PATCH v2] hwmon: (adt7462) Fix overflows seen when writing into limit attributes

[Guenter Roeck]

Fix overflows seen when writing large values into temperature limit,
voltage limit, and pwm hysteresis attributes.

The input parameter to DIV_ROUND_CLOSEST() needs to be clamped to avoid
such overflows.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v2: Simplified clamping
    Separate clamp_val() and DIV_ROUND_CLOSEST() into two lines.

 drivers/hwmon/adt7462.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/hwmon/adt7462.c b/drivers/hwmon/adt7462.c
index 5929e126da63..19f2a6d48bac 100644
--- a/drivers/hwmon/adt7462.c
+++ b/drivers/hwmon/adt7462.c
@@ -810,8 +810,8 @@ static ssize_t set_temp_min(struct device *dev,
 	if (kstrtol(buf, 10, &temp) || !temp_enabled(data, attr->index))
 		return -EINVAL;
 
+	temp = clamp_val(temp, -64000, 191000);
 	temp = DIV_ROUND_CLOSEST(temp, 1000) + 64;
-	temp = clamp_val(temp, 0, 255);
 
 	mutex_lock(&data->lock);
 	data->temp_min[attr->index] = temp;
@@ -848,8 +848,8 @@ static ssize_t set_temp_max(struct device *dev,
 	if (kstrtol(buf, 10, &temp) || !temp_enabled(data, attr->index))
 		return -EINVAL;
 
+	temp = clamp_val(temp, -64000, 191000);
 	temp = DIV_ROUND_CLOSEST(temp, 1000) + 64;
-	temp = clamp_val(temp, 0, 255);
 
 	mutex_lock(&data->lock);
 	data->temp_max[attr->index] = temp;
@@ -912,9 +912,9 @@ static ssize_t set_volt_max(struct device *dev,
 	if (kstrtol(buf, 10, &temp) || !x)
 		return -EINVAL;
 
+	temp = clamp_val(temp, 0, 255 * x / 1000);
 	temp *= 1000; /* convert mV to uV */
 	temp = DIV_ROUND_CLOSEST(temp, x);
-	temp = clamp_val(temp, 0, 255);
 
 	mutex_lock(&data->lock);
 	data->volt_max[attr->index] = temp;
@@ -954,9 +954,9 @@ static ssize_t set_volt_min(struct device *dev,
 	if (kstrtol(buf, 10, &temp) || !x)
 		return -EINVAL;
 
+	temp = clamp_val(temp, 0, 255 * x / 1000);
 	temp *= 1000; /* convert mV to uV */
 	temp = DIV_ROUND_CLOSEST(temp, x);
-	temp = clamp_val(temp, 0, 255);
 
 	mutex_lock(&data->lock);
 	data->volt_min[attr->index] = temp;
@@ -1220,8 +1220,8 @@ static ssize_t set_pwm_hyst(struct device *dev,
 	if (kstrtol(buf, 10, &temp))
 		return -EINVAL;
 
+	temp = clamp_val(temp, 0, 15000);
 	temp = DIV_ROUND_CLOSEST(temp, 1000);
-	temp = clamp_val(temp, 0, 15);
 
 	/* package things up */
 	temp &= ADT7462_PWM_HYST_MASK;
@@ -1306,8 +1306,8 @@ static ssize_t set_pwm_tmin(struct device *dev,
 	if (kstrtol(buf, 10, &temp))
 		return -EINVAL;
 
+	temp = clamp_val(temp, -64000, 191000);
 	temp = DIV_ROUND_CLOSEST(temp, 1000) + 64;
-	temp = clamp_val(temp, 0, 255);
 
 	mutex_lock(&data->lock);
 	data->pwm_tmin[attr->index] = temp;
-- 
2.5.0

Re: [PATCH v2] hwmon: (adt7462) Fix overflows seen when writing into limit attributes

[Jean Delvare]

On Thu,  8 Dec 2016 11:26:49 -0800, Guenter Roeck wrote:
> Fix overflows seen when writing large values into temperature limit,
> voltage limit, and pwm hysteresis attributes.
> 
> The input parameter to DIV_ROUND_CLOSEST() needs to be clamped to avoid
> such overflows.
> 
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> ---
> v2: Simplified clamping
>     Separate clamp_val() and DIV_ROUND_CLOSEST() into two lines.
> 
>  drivers/hwmon/adt7462.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> (...)

Reviewed-by: Jean Delvare <jdelvare@suse.de>

-- 
Jean Delvare
SUSE L3 Support