[PATCH] leds: mt6370: Annotate struct mt6370_priv with __counted_by

[Kees Cook]

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 mt6370_priv.

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

Cc: Pavel Machek <pavel at ucw.cz>
Cc: Lee Jones <lee at kernel.org>
Cc: Matthias Brugger <matthias.bgg at gmail.com>
Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>
Cc: Alice Chen <alice_chen at richtek.com>
Cc: Jacek Anaszewski <jacek.anaszewski at gmail.com>
Cc: ChiYuan Huang <cy_huang at richtek.com>
Cc: ChiaEn Wu <chiaen_wu at richtek.com>
Cc: kernel test robot <lkp at intel.com>
Cc: linux-leds at vger.kernel.org
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-mediatek at lists.infradead.org
Signed-off-by: Kees Cook <keescook at chromium.org>
---
 drivers/leds/flash/leds-mt6370-flash.c | 2 +-
 drivers/leds/rgb/leds-mt6370-rgb.c     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/leds/flash/leds-mt6370-flash.c b/drivers/leds/flash/leds-mt6370-flash.c
index 931067c8a75f..912d9d622320 100644
--- a/drivers/leds/flash/leds-mt6370-flash.c
+++ b/drivers/leds/flash/leds-mt6370-flash.c
@@ -81,7 +81,7 @@ struct mt6370_priv {
 	unsigned int fled_torch_used;
 	unsigned int leds_active;
 	unsigned int leds_count;
-	struct mt6370_led leds[];
+	struct mt6370_led leds[] __counted_by(leds_count);
 };
 
 static int mt6370_torch_brightness_set(struct led_classdev *lcdev, enum led_brightness level)
diff --git a/drivers/leds/rgb/leds-mt6370-rgb.c b/drivers/leds/rgb/leds-mt6370-rgb.c
index bb62431efe83..448d0da11848 100644
--- a/drivers/leds/rgb/leds-mt6370-rgb.c
+++ b/drivers/leds/rgb/leds-mt6370-rgb.c
@@ -153,7 +153,7 @@ struct mt6370_priv {
 	const struct mt6370_pdata *pdata;
 	unsigned int leds_count;
 	unsigned int leds_active;
-	struct mt6370_led leds[];
+	struct mt6370_led leds[] __counted_by(leds_count);
 };
 
 static const struct reg_field common_reg_fields[F_MAX_FIELDS] = {
-- 
2.34.1