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Message-ID: <4d5e29e0-cd74-37e3-6305-d5c8daedf7c3@embeddedor.com>
Date:   Sat, 23 Sep 2023 10:35:28 -0600
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Subject: Re: [PATCH] gcov: Annotate struct gcov_iterator with __counted_by
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To:     Kees Cook <keescook@chromium.org>,
        Peter Oberparleiter <oberpar@linux.ibm.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: <20230922175220.work.327-kees@kernel.org>
From:   "Gustavo A. R. Silva" <gustavo@embeddedor.com>
In-Reply-To: <20230922175220.work.327-kees@kernel.org>
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On 9/22/23 11:52, 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 gcov_iterator.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Peter Oberparleiter <oberpar@linux.ibm.com>
> Signed-off-by: Kees Cook <keescook@chromium.org>

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

Thanks
-- 
Gustavo

> ---
>   kernel/gcov/fs.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/gcov/fs.c b/kernel/gcov/fs.c
> index 5c3086cad8f9..01520689b57c 100644
> --- a/kernel/gcov/fs.c
> +++ b/kernel/gcov/fs.c
> @@ -99,7 +99,7 @@ struct gcov_iterator {
>   	struct gcov_info *info;
>   	size_t size;
>   	loff_t pos;
> -	char buffer[];
> +	char buffer[] __counted_by(size);
>   };
>   
>   /**