Commit e623c430 authored by Bartosz Golaszewski's avatar Bartosz Golaszewski
Browse files

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



As per the API contract, the get_direction() callback can only
return 0, 1 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-v1-8-12ea88506cb2@linaro.org


Signed-off-by: default avatarBartosz Golaszewski <bartosz.golaszewski@linaro.org>
parent 4750ddce

drivers/gpio/gpiolib.c

+21 −6
Original line number Diff line number Diff line
@@ -342,6 +342,22 @@ static int gpiochip_find_base_unlocked(u16 ngpio) 
	}

}



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

{

	int ret;



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



	if (WARN_ON(!gc->get_direction))

		return -EOPNOTSUPP;



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

	if (ret > 1)

		ret = -EBADE;



	return ret;

}



/**

 * gpiod_get_direction - return the current direction of a GPIO

 * @desc:	GPIO to get the direction of
@@ -382,7 +398,7 @@ int gpiod_get_direction(struct gpio_desc *desc) 
	if (!guard.gc->get_direction)

		return -ENOTSUPP;



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

	ret = gpiochip_get_direction(guard.gc, offset);

	if (ret < 0)

		return ret;
@@ -1067,7 +1083,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, 
		desc->gdev = gdev;



		if (gc->get_direction && gpiochip_line_is_valid(gc, desc_index)) {

			ret = gc->get_direction(gc, desc_index);

			ret = gpiochip_get_direction(gc, desc_index);

			if (ret < 0)

				/*

				 * FIXME: Bail-out here once all GPIO drivers
@@ -2788,8 +2804,7 @@ int gpiod_direction_input_nonotify(struct gpio_desc *desc) 
		ret = gpiochip_direction_input(guard.gc,

					       gpio_chip_hwgpio(desc));

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

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

					      gpio_chip_hwgpio(desc));

		ret = gpiochip_get_direction(guard.gc, gpio_chip_hwgpio(desc));

		if (ret < 0)

			return ret;
@@ -2836,7 +2851,7 @@ static int gpiod_direction_output_raw_commit(struct gpio_desc *desc, int value) 
	} else {

		/* Check that we are in output mode if we can */

		if (guard.gc->get_direction) {

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

			ret = gpiochip_get_direction(guard.gc,

						     gpio_chip_hwgpio(desc));

			if (ret < 0)

				return ret;