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

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The return value of the direction_input() 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: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20250210-gpio-sanitize-retvals-v1-7-12ea88506cb2@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
This commit is contained in:
Bartosz Golaszewski 2025-02-10 11:52:01 +01:00
parent dfeb70c86d
commit 4750ddce95
1 changed files with 20 additions and 4 deletions
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24
drivers/gpio/gpiolib.c
View file

@ -2701,6 +2701,22 @@ int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce)
return ret;
}
static int gpiochip_direction_input(struct gpio_chip *gc, unsigned int offset)
{
int ret;
lockdep_assert_held(&gc->gpiodev->srcu);
if (WARN_ON(!gc->direction_input))
return -EOPNOTSUPP;
ret = gc->direction_input(gc, offset);
if (ret > 0)
ret = -EBADE;
return ret;
}
static int gpiochip_direction_output(struct gpio_chip *gc, unsigned int offset,
int value)
{
@ -2769,8 +2785,8 @@ int gpiod_direction_input_nonotify(struct gpio_desc *desc)
* assume we are in input mode after this.
*/
if (guard.gc->direction_input) {
ret = guard.gc->direction_input(guard.gc,
gpio_chip_hwgpio(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));
@ -3475,7 +3491,7 @@ static void gpio_set_open_drain_value_commit(struct gpio_desc *desc, bool value)
return;
if (value) {
ret = guard.gc->direction_input(guard.gc, offset);
ret = gpiochip_direction_input(guard.gc, offset);
} else {
ret = gpiochip_direction_output(guard.gc, offset, 0);
if (!ret)
@ -3506,7 +3522,7 @@ static void gpio_set_open_source_value_commit(struct gpio_desc *desc, bool value
if (!ret)
set_bit(FLAG_IS_OUT, &desc->flags);
} else {
ret = guard.gc->direction_input(guard.gc, offset);
ret = gpiochip_direction_input(guard.gc, offset);
}
trace_gpio_direction(desc_to_gpio(desc), !value, ret);
if (ret < 0)