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: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250210-gpio-sanitize-retvals-v1-8-12ea88506cb2@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
This commit is contained in:
Bartosz Golaszewski 2025-02-10 11:52:02 +01:00
parent 4750ddce95
commit e623c4303e

View File

@ -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;
@ -2836,8 +2851,8 @@ 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,
gpio_chip_hwgpio(desc));
ret = gpiochip_get_direction(guard.gc,
gpio_chip_hwgpio(desc));
if (ret < 0)
return ret;