mlxsw: spectrum_kvdl: Use struct_size() helper in kzalloc()

Make use of the struct_size() helper instead of an open-coded version,
in order to avoid any potential type mistakes or integer overflows that,
in the worst scenario, could lead to heap overflows.

Also, address the following sparse warnings:
drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c:229:24: warning: using sizeof on a flexible structure

Link: https://github.com/KSPP/linux/issues/174
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c
index a9fff8adc75e720fdf7fe1dac14a653a175372a3..d20e794e01ca0dba349bc2b6e6dc297c9e65e273 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum1_kvdl.c
@@ -213,7 +213,6 @@ mlxsw_sp1_kvdl_part_init(struct mlxsw_sp *mlxsw_sp,
        struct mlxsw_sp1_kvdl_part *part;
        bool need_update = true;
        unsigned int nr_entries;
-       size_t usage_size;
        u64 resource_size;
        int err;
 
@@ -225,8 +224,8 @@ mlxsw_sp1_kvdl_part_init(struct mlxsw_sp *mlxsw_sp,
        }
 
        nr_entries = div_u64(resource_size, info->alloc_size);
-       usage_size = BITS_TO_LONGS(nr_entries) * sizeof(unsigned long);
-       part = kzalloc(sizeof(*part) + usage_size, GFP_KERNEL);
+       part = kzalloc(struct_size(part, usage, BITS_TO_LONGS(nr_entries)),
+                      GFP_KERNEL);
        if (!part)
                return ERR_PTR(-ENOMEM);