leds: gpio: Annotate struct gpio_leds_priv with __counted_by

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS
(for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct gpio_leds_priv.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20230915201003.never.148-kees@kernel.org
Signed-off-by: Lee Jones <lee@kernel.org>

diff --git a/drivers/leds/leds-gpio.c b/drivers/leds/leds-gpio.c
index 7bfe40a6bfddfa967740e09d2768d6bc3b235497..a6597f0f3eb4d58cdca945e5f38d49ab23272e0c 100644 (file)
--- a/drivers/leds/leds-gpio.c
+++ b/drivers/leds/leds-gpio.c
@@ -142,7 +142,7 @@ static int create_gpio_led(const struct gpio_led *template,
 
 struct gpio_leds_priv {
        int num_leds;
-       struct gpio_led_data leds[];
+       struct gpio_led_data leds[] __counted_by(num_leds);
 };
 
 static struct gpio_leds_priv *gpio_leds_create(struct platform_device *pdev)