Commit dcf8f3bf authored by Bartosz Golaszewski's avatar Bartosz Golaszewski
Browse files

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



The return value of the set_config() callback may be propagated to
user-space. If a bad driver returns a positive number, it may confuse
user programs. Tighten the API contract and check for positive numbers
returned by GPIO controllers.

Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250210-gpio-sanitize-retvals-v1-3-12ea88506cb2@linaro.org


Signed-off-by: default avatarBartosz Golaszewski <bartosz.golaszewski@linaro.org>
parent 69920338

drivers/gpio/gpiolib.c

+3 −0
Original line number Diff line number Diff line
@@ -2593,6 +2593,9 @@ int gpio_do_set_config(struct gpio_desc *desc, unsigned long config) 
		return -ENOTSUPP;



	ret = guard.gc->set_config(guard.gc, gpio_chip_hwgpio(desc), config);

	if (ret > 0)

		ret = -EBADE;



#ifdef CONFIG_GPIO_CDEV

	/*

	 * Special case - if we're setting debounce period, we need to store

include/linux/gpio/driver.h

+2 −1
Original line number Diff line number Diff line
@@ -349,7 +349,8 @@ struct gpio_irq_chip { 
 * @set: assigns output value for signal "offset"

 * @set_multiple: assigns output values for multiple signals defined by "mask"

 * @set_config: optional hook for all kinds of settings. Uses the same

 *	packed config format as generic pinconf.

 *	packed config format as generic pinconf. Must return 0 on success and

 *	a negative error number on failure.

 * @to_irq: optional hook supporting non-static gpiod_to_irq() mappings;

 *	implementation may not sleep

 * @dbg_show: optional routine to show contents in debugfs; default code