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

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The return value of the direction_output() 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-v1-6-12ea88506cb2@linaro.org
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
This commit is contained in:
Bartosz Golaszewski
2025-02-10 11:52:00 +01:00
parent 74abd086d2
commit dfeb70c86d
1 changed files with 21 additions and 4 deletions
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25
drivers/gpio/gpiolib.c
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@@ -2701,6 +2701,23 @@ int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce)
return ret;
}
static int gpiochip_direction_output(struct gpio_chip *gc, unsigned int offset,
int value)
{
int ret;
lockdep_assert_held(&gc->gpiodev->srcu);
if (WARN_ON(!gc->direction_output))
return -EOPNOTSUPP;
ret = gc->direction_output(gc, offset, value);
if (ret > 0)
ret = -EBADE;
return ret;
}
/**
* gpiod_direction_input - set the GPIO direction to input
* @desc: GPIO to set to input
@@ -2798,8 +2815,8 @@ static int gpiod_direction_output_raw_commit(struct gpio_desc *desc, int value)
}
if (guard.gc->direction_output) {
ret = guard.gc->direction_output(guard.gc,
gpio_chip_hwgpio(desc), val);
ret = gpiochip_direction_output(guard.gc,
gpio_chip_hwgpio(desc), val);
} else {
/* Check that we are in output mode if we can */
if (guard.gc->get_direction) {
@@ -3460,7 +3477,7 @@ static void gpio_set_open_drain_value_commit(struct gpio_desc *desc, bool value)
if (value) {
ret = guard.gc->direction_input(guard.gc, offset);
} else {
ret = guard.gc->direction_output(guard.gc, offset, 0);
ret = gpiochip_direction_output(guard.gc, offset, 0);
if (!ret)
set_bit(FLAG_IS_OUT, &desc->flags);
}
@@ -3485,7 +3502,7 @@ static void gpio_set_open_source_value_commit(struct gpio_desc *desc, bool value
return;
if (value) {
ret = guard.gc->direction_output(guard.gc, offset, 1);
ret = gpiochip_direction_output(guard.gc, offset, 1);
if (!ret)
set_bit(FLAG_IS_OUT, &desc->flags);
} else {