[PATCH 4/5] mlxsw: spectrum_router: Annotate struct mlxsw_sp_nexthop_group_info with __counted_by

Kees Cook
2023-09-29T18:08:01Z

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_nexthop_group_info.

[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>
---
drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
index debd2c466f11..82a95125d9ca 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -3107,7 +3107,7 @@ struct mlxsw_sp_nexthop_group_info {
gateway:1, /* routes using the group use a gateway */
is_resilient:1;
struct list_head list; /* member in nh_res_grp_list */
- struct mlxsw_sp_nexthop nexthops[];
+ struct mlxsw_sp_nexthop nexthops[] __counted_by(count);
};

static struct mlxsw_sp_rif *
--
2.34.1