[PATCH] leds: gpio: Annotate struct gpio_leds_priv with __counted_by

From: Kees Cook <keescook@chromium.org>
To: Pavel Machek <pavel@ucw.cz>
Cc: Kees Cook <keescook@chromium.org>, Lee Jones <lee@kernel.org>,
	linux-leds@vger.kernel.org, Nathan Chancellor <nathan@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Tom Rix <trix@redhat.com>,
	linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
	linux-hardening@vger.kernel.org
Subject: [PATCH] leds: gpio: Annotate struct gpio_leds_priv with __counted_by
Date: Fri, 15 Sep 2023 13:10:04 -0700	[thread overview]
Message-ID: <20230915201003.never.148-kees@kernel.org> (raw)

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

Cc: Pavel Machek <pavel@ucw.cz>
Cc: Lee Jones <lee@kernel.org>
Cc: linux-leds@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/leds/leds-gpio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/leds/leds-gpio.c b/drivers/leds/leds-gpio.c
index 7bfe40a6bfdd..a6597f0f3eb4 100644
--- 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)
-- 
2.34.1

