Commit b8d5acdc authored by Gui-Dong Han's avatar Gui-Dong Han Committed by Guenter Roeck
Browse files

hwmon: (max16065) Use local variable to avoid TOCTOU 

In max16065_current_show, data->curr_sense is read twice: once for the
error check and again for the calculation. Since
i2c_smbus_read_byte_data returns negative error codes on failure, if the
data changes to an error code between the check and the use, ADC_TO_CURR
results in an incorrect calculation.

Read data->curr_sense into a local variable to ensure consistency. Note
that data->curr_gain is constant and safe to access directly.

This aligns max16065_current_show with max16065_input_show, which
already uses a local variable for the same reason.

Link: https://lore.kernel.org/all/CALbr=LYJ_ehtp53HXEVkSpYoub+XYSTU8Rg=o1xxMJ8=5z8B-g@mail.gmail.com/


Fixes: f5bae264 ("hwmon: Driver for MAX16065 System Manager and compatibles")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarGui-Dong Han <hanguidong02@gmail.com>
Link: https://lore.kernel.org/r/20251128124709.3876-1-hanguidong02@gmail.com


Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 07272e88

drivers/hwmon/max16065.c

+4 −3
Original line number Diff line number Diff line
@@ -216,12 +216,13 @@ static ssize_t max16065_current_show(struct device *dev, 
				     struct device_attribute *da, char *buf)

{

	struct max16065_data *data = max16065_update_device(dev);

	int curr_sense = data->curr_sense;



	if (unlikely(data->curr_sense < 0))

		return data->curr_sense;

	if (unlikely(curr_sense < 0))

		return curr_sense;



	return sysfs_emit(buf, "%d\n",

			  ADC_TO_CURR(data->curr_sense, data->curr_gain));

			  ADC_TO_CURR(curr_sense, data->curr_gain));

}



static ssize_t max16065_limit_store(struct device *dev,