[PATCH] leds: lm3697: Annotate struct lm3697 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: lm3697: Annotate struct lm3697 with __counted_by
Date: Fri, 15 Sep 2023 13:10:10 -0700	[thread overview]
Message-ID: <20230915201010.never.399-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 lm3697.

[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-lm3697.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/leds/leds-lm3697.c b/drivers/leds/leds-lm3697.c
index cfb8ac220db6..380d17a58fe9 100644
--- a/drivers/leds/leds-lm3697.c
+++ b/drivers/leds/leds-lm3697.c
@@ -89,7 +89,7 @@ struct lm3697 {
 	int bank_cfg;
 	int num_banks;
 
-	struct lm3697_led leds[];
+	struct lm3697_led leds[] __counted_by(num_banks);
 };
 
 static const struct reg_default lm3697_reg_defs[] = {
-- 
2.34.1

