Commit 4750ddce authored by Bartosz Golaszewski's avatar Bartosz Golaszewski
Browse files

gpiolib: sanitize the return value of gpio_chip::direction_input() 



The return value of the direction_input() callback may be propagated to
user-space. As per the API contract it can only return 0 or a negative
error number. Add a wrapper around the callback calls that filters out
anything else.

Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250210-gpio-sanitize-retvals-v1-7-12ea88506cb2@linaro.org


Signed-off-by: default avatarBartosz Golaszewski <bartosz.golaszewski@linaro.org>
parent dfeb70c8

drivers/gpio/gpiolib.c

+20 −4
Original line number Diff line number Diff line
@@ -2701,6 +2701,22 @@ int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce) 
	return ret;

}



static int gpiochip_direction_input(struct gpio_chip *gc, unsigned int offset)

{

	int ret;



	lockdep_assert_held(&gc->gpiodev->srcu);



	if (WARN_ON(!gc->direction_input))

		return -EOPNOTSUPP;



	ret = gc->direction_input(gc, offset);

	if (ret > 0)

		ret = -EBADE;



	return ret;

}



static int gpiochip_direction_output(struct gpio_chip *gc, unsigned int offset,

				     int value)

{
@@ -2769,7 +2785,7 @@ int gpiod_direction_input_nonotify(struct gpio_desc *desc) 
	 * assume we are in input mode after this.

	 */

	if (guard.gc->direction_input) {

		ret = guard.gc->direction_input(guard.gc,

		ret = gpiochip_direction_input(guard.gc,

					       gpio_chip_hwgpio(desc));

	} else if (guard.gc->get_direction) {

		ret = guard.gc->get_direction(guard.gc,
@@ -3475,7 +3491,7 @@ static void gpio_set_open_drain_value_commit(struct gpio_desc *desc, bool value) 
		return;



	if (value) {

		ret = guard.gc->direction_input(guard.gc, offset);

		ret = gpiochip_direction_input(guard.gc, offset);

	} else {

		ret = gpiochip_direction_output(guard.gc, offset, 0);

		if (!ret)
@@ -3506,7 +3522,7 @@ static void gpio_set_open_source_value_commit(struct gpio_desc *desc, bool value 
		if (!ret)

			set_bit(FLAG_IS_OUT, &desc->flags);

	} else {

		ret = guard.gc->direction_input(guard.gc, offset);

		ret = gpiochip_direction_input(guard.gc, offset);

	}

	trace_gpio_direction(desc_to_gpio(desc), !value, ret);

	if (ret < 0)