Commit 69920338 authored Feb 10, 2025 by Bartosz Golaszewski

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

The return value of the request() 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: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250210-gpio-sanitize-retvals-v1-2-12ea88506cb2@linaro.org

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

parent 2d13f801

drivers/gpio/gpiolib.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -2349,6 +2349,8 @@ static int gpiod_request_commit(struct gpio_desc desc, const char label)
		ret = guard.gc->request(guard.gc, offset);
		else
		ret = -EINVAL;
		if (ret > 0)
		ret = -EBADE;
		if (ret)
		goto out_clear_bit;
		}

include/linux/gpio/driver.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -329,7 +329,8 @@ struct gpio_irq_chip {
		* @fwnode: optional fwnode providing this controller's properties
		* @owner: helps prevent removal of modules exporting active GPIOs
		* @request: optional hook for chip-specific activation, such as
		* enabling module power and clock; may sleep
		* enabling module power and clock; may sleep; must return 0 on success
		* or negative error number on failure
		* @free: optional hook for chip-specific deactivation, such as
		* disabling module power and clock; may sleep
		* @get_direction: returns direction for signal "offset", 0=out, 1=in,