[PATCH 8/8] gpiolib: sanitize the return value of gpio_chip::get_direction()
From: Bartosz Golaszewski
Date: Mon Feb 10 2025 - 05:53:55 EST
From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
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.
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
---
drivers/gpio/gpiolib.c | 27 +++++++++++++++++++++------
1 file changed, 21 insertions(+), 6 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 683a03d237c0..7f2aca9f81a1 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -341,6 +341,22 @@ 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
@@ -381,7 +397,7 @@ 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;
@@ -1057,7 +1073,7 @@ 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)
goto err_cleanup_desc_srcu;
@@ -2770,8 +2786,7 @@ 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;
@@ -2818,8 +2833,8 @@ 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;
--
2.45.2