[PATCH v4 1/4] gpiolib: acpi: Add robust bounds-checking for GPIO pin resources

[Marco Scardovi <scardracs@disroot.org>]

From: "Marco Scardovi (scardracs)" <mscardovi95@gmail.com>

Ensure that the GPIO pin resource arrays are safely bounded before
accessing indices. Add bounds checking in acpi_request_own_gpiod(),
acpi_gpio_irq_is_wake(), and acpi_gpiochip_alloc_event() to prevent
out-of-bounds array reads if the ACPI namespace provides malformed or
empty pin tables.

Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Marco Scardovi <mscardovi95@gmail.com>
---
 drivers/gpio/gpiolib-acpi-core.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/gpio/gpiolib-acpi-core.c b/drivers/gpio/gpiolib-acpi-core.c
index eb8a40cfb7a9..a6d78dad299e 100644
--- a/drivers/gpio/gpiolib-acpi-core.c
+++ b/drivers/gpio/gpiolib-acpi-core.c
@@ -320,10 +320,18 @@ static struct gpio_desc *acpi_request_own_gpiod(struct gpio_chip *chip,
 						unsigned int index,
 						const char *label)
 {
-	int polarity = GPIO_ACTIVE_HIGH;
-	enum gpiod_flags flags = acpi_gpio_to_gpiod_flags(agpio, polarity);
-	unsigned int pin = agpio->pin_table[index];
 	struct gpio_desc *desc;
+	enum gpiod_flags flags;
+	unsigned int pin;
+	int polarity;
+
+	polarity = GPIO_ACTIVE_HIGH;
+	flags = acpi_gpio_to_gpiod_flags(agpio, polarity);
+
+	if (index >= agpio->pin_table_length)
+		return ERR_PTR(-EINVAL);
+
+	pin = agpio->pin_table[index];
 
 	desc = gpiochip_request_own_desc(chip, pin, label, polarity, flags);
 	if (IS_ERR(desc))
@@ -337,11 +345,16 @@ static struct gpio_desc *acpi_request_own_gpiod(struct gpio_chip *chip,
 static bool acpi_gpio_irq_is_wake(struct device *parent,
 				  const struct acpi_resource_gpio *agpio)
 {
-	unsigned int pin = agpio->pin_table[0];
+	unsigned int pin;
 
 	if (agpio->wake_capable != ACPI_WAKE_CAPABLE)
 		return false;
 
+	if (agpio->pin_table_length == 0)
+		return false;
+
+	pin = agpio->pin_table[0];
+
 	if (acpi_gpio_in_ignore_list(ACPI_GPIO_IGNORE_WAKE, dev_name(parent), pin)) {
 		dev_info(parent, "Ignoring wakeup on pin %u\n", pin);
 		return false;
@@ -368,6 +381,9 @@ static acpi_status acpi_gpiochip_alloc_event(struct acpi_resource *ares,
 		return AE_OK;
 
 	handle = ACPI_HANDLE(chip->parent);
+	if (agpio->pin_table_length == 0)
+		return AE_OK;
+
 	pin = agpio->pin_table[0];
 
 	if (pin <= 255) {
-- 
2.54.0