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Message-ID: <30e6453f-95cc-05fa-9582-6b7447d8e2e6@linux.alibaba.com>
Date:   Sun, 17 Sep 2023 23:03:03 +0800
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Subject: Re: [PATCH] ocfs2: Annotate struct ocfs2_slot_info with __counted_by
To:     Kees Cook <keescook@chromium.org>, Mark Fasheh <mark@fasheh.com>,
        akpm <akpm@linux-foundation.org>
Cc:     Joel Becker <jlbec@evilplan.org>, ocfs2-devel@lists.linux.dev,
        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: <20230915201522.never.979-kees@kernel.org>
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From:   Joseph Qi <joseph.qi@linux.alibaba.com>
In-Reply-To: <20230915201522.never.979-kees@kernel.org>
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On 9/16/23 4:15 AM, 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 ocfs2_slot_info.
> 
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> 
> Cc: Mark Fasheh <mark@fasheh.com>
> Cc: Joel Becker <jlbec@evilplan.org>
> Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
> Cc: ocfs2-devel@lists.linux.dev
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
> ---
>  fs/ocfs2/slot_map.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/ocfs2/slot_map.c b/fs/ocfs2/slot_map.c
> index da7718cef735..e544c704b583 100644
> --- a/fs/ocfs2/slot_map.c
> +++ b/fs/ocfs2/slot_map.c
> @@ -37,7 +37,7 @@ struct ocfs2_slot_info {
>  	unsigned int si_blocks;
>  	struct buffer_head **si_bh;
>  	unsigned int si_num_slots;
> -	struct ocfs2_slot si_slots[];
> +	struct ocfs2_slot si_slots[] __counted_by(si_num_slots);
>  };
>  
>