mlxsw: Annotate struct mlxsw_linecards with __counted_by

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_linecards.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc: Petr Machata <petrm@nvidia.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/20230929180746.3005922-1-keescook@chromium.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/mellanox/mlxsw/core.h b/drivers/net/ethernet/mellanox/mlxsw/core.h
index e5474d3e34db016836094caa9b773c0d8f7950eb..c6bc5819ce4386f239757174d92d7728d1adcf0a 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlxsw/core.h
+++ b/drivers/net/ethernet/mellanox/mlxsw/core.h
@@ -624,7 +624,7 @@ struct mlxsw_linecards {
        struct mlxsw_linecard_types_info *types_info;
        struct list_head event_ops_list;
        struct mutex event_ops_list_lock; /* Locks accesses to event ops list */
-       struct mlxsw_linecard linecards[];
+       struct mlxsw_linecard linecards[] __counted_by(count);
 };
 
 static inline struct mlxsw_linecard *