On Tue, Oct 3, 2023 at 4:17 PM Kees Cook <keesc...@chromium.org> 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 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 mlx5_fc_bulk.
>
> Cc: Saeed Mahameed <sae...@nvidia.com>
> Cc: Leon Romanovsky <l...@kernel.org>
> Cc: "David S. Miller" <da...@davemloft.net>
> Cc: Eric Dumazet <eduma...@google.com>
> Cc: Jakub Kicinski <k...@kernel.org>
> Cc: Paolo Abeni <pab...@redhat.com>
> Cc: net...@vger.kernel.org
> Cc: linux-r...@vger.kernel.org
> Link:
> https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
> [1]
> Signed-off-by: Kees Cook <keesc...@chromium.org>
> ---
> drivers/net/ethernet/mellanox/mlx5/core/fs_counters.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/fs_counters.c
> b/drivers/net/ethernet/mellanox/mlx5/core/fs_counters.c
> index 17fe30a4c06c..0c26d707eed2 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/fs_counters.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/fs_counters.c
> @@ -539,7 +539,7 @@ struct mlx5_fc_bulk {
> u32 base_id;
> int bulk_len;
> unsigned long *bitmask;
> - struct mlx5_fc fcs[];
> + struct mlx5_fc fcs[] __counted_by(bulk_len);
> };
This looks good.
`bulk->bulk_len` is assigned before flexible array member `fcs` is accessed.
bulk->bulk_len = bulk_len;
for (i = 0; i < bulk_len; i++) {
mlx5_fc_init(&bulk->fcs[i], bulk, base_id + i);
set_bit(i, bulk->bitmask);
}
Reviewed-by: Justin Stitt <justinst...@google.com>
>
> static void mlx5_fc_init(struct mlx5_fc *counter, struct mlx5_fc_bulk *bulk,
> --
> 2.34.1
>
>
Thanks
Justin
