Re: [PATCH] ocfs2: Annotate struct ocfs2_slot_info with __counted_by

[Joseph Qi]

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@xxxxxxxxxx>
> Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
> Cc: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
> Cc: ocfs2-devel@xxxxxxxxxxxxxxx
> Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>

Reviewed-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
> ---
>  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);
>  };
>  
>