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Message-ID: <118576aa-a667-8c91-821a-351562dc4c61@embeddedor.com>
Date:   Fri, 15 Sep 2023 14:50:14 -0600
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Subject: Re: [PATCH] udf: Annotate struct udf_bitmap with __counted_by
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To:     Kees Cook <keescook@chromium.org>, Jan Kara <jack@suse.com>
Cc:     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: <20230915201404.never.574-kees@kernel.org>
From:   "Gustavo A. R. Silva" <gustavo@embeddedor.com>
In-Reply-To: <20230915201404.never.574-kees@kernel.org>
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On 9/15/23 14:14, 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 udf_bitmap.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Jan Kara <jack@suse.com>
> Signed-off-by: Kees Cook <keescook@chromium.org>

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

Thanks
-- 
Gustavo

> ---
>   fs/udf/udf_sb.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/udf/udf_sb.h b/fs/udf/udf_sb.h
> index 9af6ff7f9747..f9a60bc1abcf 100644
> --- a/fs/udf/udf_sb.h
> +++ b/fs/udf/udf_sb.h
> @@ -86,7 +86,7 @@ struct udf_virtual_data {
>   struct udf_bitmap {
>   	__u32			s_extPosition;
>   	int			s_nr_groups;
> -	struct buffer_head	*s_block_bitmap[];
> +	struct buffer_head	*s_block_bitmap[] __counted_by(s_nr_groups);
>   };
>   
>   struct udf_part_map {