Commit dfeb70c8 authored by Bartosz Golaszewski's avatar Bartosz Golaszewski
Browse files

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



The return value of the direction_output() 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-v1-6-12ea88506cb2@linaro.org


Signed-off-by: default avatarBartosz Golaszewski <bartosz.golaszewski@linaro.org>
parent 74abd086

drivers/gpio/gpiolib.c

+21 −4
Original line number Diff line number Diff line
@@ -2701,6 +2701,23 @@ int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce) 
	return ret;

}



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

				     int value)

{

	int ret;



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



	if (WARN_ON(!gc->direction_output))

		return -EOPNOTSUPP;



	ret = gc->direction_output(gc, offset, value);

	if (ret > 0)

		ret = -EBADE;



	return ret;

}



/**

 * gpiod_direction_input - set the GPIO direction to input

 * @desc:	GPIO to set to input
@@ -2798,7 +2815,7 @@ static int gpiod_direction_output_raw_commit(struct gpio_desc *desc, int value) 
	}



	if (guard.gc->direction_output) {

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

		ret = gpiochip_direction_output(guard.gc,

						gpio_chip_hwgpio(desc), val);

	} else {

		/* Check that we are in output mode if we can */
@@ -3460,7 +3477,7 @@ static void gpio_set_open_drain_value_commit(struct gpio_desc *desc, bool value) 
	if (value) {

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

	} else {

		ret = guard.gc->direction_output(guard.gc, offset, 0);

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

		if (!ret)

			set_bit(FLAG_IS_OUT, &desc->flags);

	}
@@ -3485,7 +3502,7 @@ static void gpio_set_open_source_value_commit(struct gpio_desc *desc, bool value 
		return;



	if (value) {

		ret = guard.gc->direction_output(guard.gc, offset, 1);

		ret = gpiochip_direction_output(guard.gc, offset, 1);

		if (!ret)

			set_bit(FLAG_IS_OUT, &desc->flags);

	} else {