net/mlx5: DR, Fix wrong action data allocation in decap action

When TUNNEL_L3_TO_L2 decap action was created, a pointer to a local
variable was passed as its HW action data, resulting in attempt to
free invalid address:

  BUG: KASAN: invalid-free in mlx5dr_action_destroy+0x318/0x410 [mlx5_core]

Fixes: 4781df9 ("net/mlx5: DR, Move STEv0 modify header logic")
Signed-off-by: Yevgeny Kliteynik <kliteyn@nvidia.com>
Reviewed-by: Alex Vesker <valex@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

Author: kliteyn

drivers/net/ethernet/mellanox/mlx5/core/steering/dr_action.c

@@ -1421,16 +1421,21 @@ dr_action_create_reformat_action(struct mlx5dr_domain *dmn,
 	}
 	case DR_ACTION_TYP_TNL_L3_TO_L2:
 	{
-		u8 hw_actions[DR_ACTION_CACHE_LINE_SIZE] = {};
+		u8 *hw_actions;
 		int ret;
 
+		hw_actions = kzalloc(DR_ACTION_CACHE_LINE_SIZE, GFP_KERNEL);
+		if (!hw_actions)
+			return -ENOMEM;
+
 		ret = mlx5dr_ste_set_action_decap_l3_list(dmn->ste_ctx,
 							  data, data_sz,
 							  hw_actions,
 							  DR_ACTION_CACHE_LINE_SIZE,
 							  &action->rewrite->num_of_actions);
 		if (ret) {
 			mlx5dr_dbg(dmn, "Failed creating decap l3 action list\n");
+			kfree(hw_actions);
 			return ret;
 		}
 
@@ -1440,6 +1445,7 @@ dr_action_create_reformat_action(struct mlx5dr_domain *dmn,
 		ret = mlx5dr_ste_alloc_modify_hdr(action);
 		if (ret) {
 			mlx5dr_dbg(dmn, "Failed preparing reformat data\n");
+			kfree(hw_actions);
 			return ret;
 		}
 		return 0;