Re: [PATCH 3/5] mlxsw: spectrum: Annotate struct mlxsw_sp_counter_pool with __counted_by

Justin Stitt
2023-10-03T23:17:38Z

On Fri, Sep 29, 2023 at 11:08 AM Kees Cook <keescook@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 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 mlxsw_sp_counter_pool.
>
> [1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
>
> Cc: Ido Schimmel <idosch@nvidia.com>
> Cc: Petr Machata <petrm@nvidia.com>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: netdev@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Justin Stitt <justinstitt@google.com>

> ---
> drivers/net/ethernet/mellanox/mlxsw/spectrum_cnt.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_cnt.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_cnt.c
> index ee59c79156e4..50e591420bd9 100644
> --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_cnt.c
> +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_cnt.c
> @@ -24,7 +24,7 @@ struct mlxsw_sp_counter_pool {
> spinlock_t counter_pool_lock; /* Protects counter pool allocations */
> atomic_t active_entries_count;
> unsigned int sub_pools_count;
> - struct mlxsw_sp_counter_sub_pool sub_pools[];
> + struct mlxsw_sp_counter_sub_pool sub_pools[] __counted_by(sub_pools_count);
> };
>
> static const struct mlxsw_sp_counter_sub_pool mlxsw_sp_counter_sub_pools[] = {
> --
> 2.34.1
>
>
Thanks
Justin