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

[Kees Cook]

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@xxxxxxxxxx>
Cc: Petr Machata <petrm@xxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
Cc: Paolo Abeni <pabeni@xxxxxxxxxx>
Cc: netdev@xxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
 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