[PATCH] media: allegro: Annotate struct mcu_msg_push_buffers_internal 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 mcu_msg_push_buffers_internal.

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

Cc: Michael Tretter <m.tretter@xxxxxxxxxxxxxx>
Cc: Pengutronix Kernel Team <kernel@xxxxxxxxxxxxxx>
Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Cc: linux-media@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
 drivers/media/platform/allegro-dvt/allegro-mail.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/platform/allegro-dvt/allegro-mail.h b/drivers/media/platform/allegro-dvt/allegro-mail.h
index a5686058d754..c0c9013f1aab 100644
--- a/drivers/media/platform/allegro-dvt/allegro-mail.h
+++ b/drivers/media/platform/allegro-dvt/allegro-mail.h
@@ -184,7 +184,7 @@ struct mcu_msg_push_buffers_internal {
 	struct mcu_msg_header header;
 	u32 channel_id;
 	size_t num_buffers;
-	struct mcu_msg_push_buffers_internal_buffer buffer[];
+	struct mcu_msg_push_buffers_internal_buffer buffer[] __counted_by(num_buffers);
 };
 
 struct mcu_msg_put_stream_buffer {
-- 
2.34.1