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From:   Kees Cook <keescook@chromium.org>
To:     Pavel Machek <pavel@ucw.cz>
Cc:     Kees Cook <keescook@chromium.org>, Lee Jones <lee@kernel.org>,
        Bjorn Andersson <quic_bjorande@quicinc.com>,
        =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= 
        <u.kleine-koenig@pengutronix.de>,
        Douglas Anderson <dianders@chromium.org>,
        Anjelique Melendez <quic_amelende@quicinc.com>,
        linux-leds@vger.kernel.org, Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>,
        Neil Armstrong <neil.armstrong@linaro.org>,
        Luca Weiss <luca@z3ntu.xyz>, Lu Hongfei <luhongfei@vivo.com>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
        linux-hardening@vger.kernel.org
Subject: [PATCH] leds: qcom-lpg: Annotate struct lpg_led with __counted_by
Date:   Fri, 15 Sep 2023 13:11:00 -0700
Message-Id: <20230915201059.never.086-kees@kernel.org>
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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 lpg_led.

[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: Bjorn Andersson <quic_bjorande@quicinc.com>
Cc: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Anjelique Melendez <quic_amelende@quicinc.com>
Cc: linux-leds@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/leds/rgb/leds-qcom-lpg.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/leds/rgb/leds-qcom-lpg.c b/drivers/leds/rgb/leds-qcom-lpg.c
index df469aaa7e6e..7d93e02a030a 100644
--- a/drivers/leds/rgb/leds-qcom-lpg.c
+++ b/drivers/leds/rgb/leds-qcom-lpg.c
@@ -173,7 +173,7 @@ struct lpg_led {
 	struct led_classdev_mc mcdev;
 
 	unsigned int num_channels;
-	struct lpg_channel *channels[];
+	struct lpg_channel *channels[] __counted_by(num_channels);
 };
 
 /**
-- 
2.34.1