Commit 86ef402d authored by Bartosz Golaszewski's avatar Bartosz Golaszewski
Browse files

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



As per the API contract, the get() callback is only allowed to 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-v1-4-12ea88506cb2@linaro.org


Signed-off-by: default avatarBartosz Golaszewski <bartosz.golaszewski@linaro.org>
parent dcf8f3bf

drivers/gpio/gpiolib.c

+18 −2
Original line number Diff line number Diff line
@@ -3115,9 +3115,25 @@ void gpiod_toggle_active_low(struct gpio_desc *desc) 
}

EXPORT_SYMBOL_GPL(gpiod_toggle_active_low);



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

{

	int ret;



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



	if (!gc->get)

		return -EIO;



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

	if (ret > 1)

		ret = -EBADE;



	return ret;

}



static int gpio_chip_get_value(struct gpio_chip *gc, const struct gpio_desc *desc)

{

	return gc->get ? gc->get(gc, gpio_chip_hwgpio(desc)) : -EIO;

	return gpiochip_get(gc, gpio_chip_hwgpio(desc));

}



/* I/O calls are only valid after configuration completed; the relevant
@@ -3174,7 +3190,7 @@ static int gpio_chip_get_multiple(struct gpio_chip *gc, 
		int i, value;



		for_each_set_bit(i, mask, gc->ngpio) {

			value = gc->get(gc, i);

			value = gpiochip_get(gc, i);

			if (value < 0)

				return value;

			__assign_bit(i, bits, value);