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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: f5bae2642e ("hwmon: Driver for MAX16065 System Manager and compatibles")
Cc: stable@vger.kernel.org
Signed-off-by: Gui-Dong Han <hanguidong02@gmail.com>
Link: https://lore.kernel.org/r/20251128124709.3876-1-hanguidong02@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
pull/1354/merge
Gui-Dong Han 2025-11-28 20:47:09 +08:00 committed by Guenter Roeck
parent 07272e883f
commit b8d5acdcf5
1 changed files with 4 additions and 3 deletions
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7
drivers/hwmon/max16065.c
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@ -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,