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Message-ID: <6dae12b4-125c-a7be-4129-75065f7a5128@embeddedor.com>
Date:   Sat, 23 Sep 2023 10:33:17 -0600
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Subject: Re: [PATCH] video: fbdev: mmp: Annotate struct mmphw_ctrl with
 __counted_by
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To:     Kees Cook <keescook@chromium.org>, Helge Deller <deller@gmx.de>
Cc:     linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.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
References: <20230922175137.work.062-kees@kernel.org>
From:   "Gustavo A. R. Silva" <gustavo@embeddedor.com>
In-Reply-To: <20230922175137.work.062-kees@kernel.org>
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On 9/22/23 11:51, Kees Cook wrote:
> 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 mmphw_ctrl.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Helge Deller <deller@gmx.de>
> Cc: linux-fbdev@vger.kernel.org
> Cc: dri-devel@lists.freedesktop.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks
-- 
Gustavo

> ---
>   drivers/video/fbdev/mmp/hw/mmp_ctrl.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/video/fbdev/mmp/hw/mmp_ctrl.h b/drivers/video/fbdev/mmp/hw/mmp_ctrl.h
> index 167585a889d3..719b99a9bc77 100644
> --- a/drivers/video/fbdev/mmp/hw/mmp_ctrl.h
> +++ b/drivers/video/fbdev/mmp/hw/mmp_ctrl.h
> @@ -1406,7 +1406,7 @@ struct mmphw_ctrl {
>   
>   	/*pathes*/
>   	int path_num;
> -	struct mmphw_path_plat path_plats[];
> +	struct mmphw_path_plat path_plats[] __counted_by(path_num);
>   };
>   
>   static inline int overlay_is_vid(struct mmp_overlay *overlay)