On Sun, 4 Dec 2016 20:55:30 -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
> ---
> drivers/hwmon/adt7462.c | 14 ++
> 1 file changed, 6 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/hwmon/adt7462.c b/drivers/hwmon/adt7462.c
> index 5929e126da63..0e9c8d3e8f5c 100644
> --- a/drivers/hwmon/adt7462.c
> +++ b/drivers/hwmon/adt7462.c
> @@ -810,8 +810,7 @@ static ssize_t set_temp_min(struct device *dev,
> if (kstrtol(buf, 10, &temp) || !temp_enabled(data, attr->index))
> return -EINVAL;
>
> - temp = DIV_ROUND_CLOSEST(temp, 1000) + 64;
> - temp = clamp_val(temp, 0, 255);
> + temp = DIV_ROUND_CLOSEST(clamp_val(temp, -64000, 191000), 1000) + 64;
>
> mutex_lock(&data->lock);
> data->temp_min[attr->index] = temp;
> @@ -848,8 +847,7 @@ static ssize_t set_temp_max(struct device *dev,
> if (kstrtol(buf, 10, &temp) || !temp_enabled(data, attr->index))
> return -EINVAL;
>
> - temp = DIV_ROUND_CLOSEST(temp, 1000) + 64;
> - temp = clamp_val(temp, 0, 255);
> + temp = DIV_ROUND_CLOSEST(clamp_val(temp, -64000, 191000), 1000) + 64;
>
> mutex_lock(&data->lock);
> data->temp_max[attr->index] = temp;
The original code had the division and the clamping on separate lines,
and I believe it makes the code more readable. It would also make the
patch smaller and more readable as well.
> @@ -912,6 +910,7 @@ static ssize_t set_volt_max(struct device *dev,
> if (kstrtol(buf, 10, &temp) || !x)
> return -EINVAL;
>
> + temp = clamp_val(temp, 0, INT_MAX / 1000 - x);
> temp *= 1000; /* convert mV to uV */
> temp = DIV_ROUND_CLOSEST(temp, x);
> temp = clamp_val(temp, 0, 255);
> @@ -954,6 +953,7 @@ static ssize_t set_volt_min(struct device *dev,
> if (kstrtol(buf, 10, &temp) || !x)
> return -EINVAL;
>
> + temp = clamp_val(temp, 0, INT_MAX / 1000 - x);
> temp *= 1000; /* convert mV to uV */
> temp = DIV_ROUND_CLOSEST(temp, x);
> temp = clamp_val(temp, 0, 255);
Any chance to get the new clamp_val()s such that the second ones are no
longer needed?
> @@ -1220,8 +1220,7 @@ static ssize_t set_pwm_hyst(struct device *dev,
> if (kstrtol(buf, 10, &temp))
> return -EINVAL;
>
> - temp = DIV_ROUND_CLOSEST(temp, 1000);
> - temp = clamp_val(temp, 0, 15);
> + temp = DIV_ROUND_CLOSEST(clamp_val(temp, 0, 15000), 1000);
>
> /* package things up */
> temp &= ADT7462_PWM_HYST_MASK;
> @@ -1306,8 +1305,7 @@ static ssize_t set_pwm_tmin(struct device *dev,
> if (kstrtol(buf, 10, &temp))
> return -EINVAL;
>
> - temp = DIV_ROUND_CLOSEST(temp, 1000) + 64;
> - temp = clamp_val(temp, 0, 255);
> + temp = DIV_ROUND_CLOSEST(clamp_val(temp, -64000, 191000), 1000) + 64;
>
> mutex_lock(&data->lock);
> data->pwm_tmin[attr->index] = temp;
Same comment as first 2.
--
Jean Delvare
SUSE L3 Support
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