2000 Chevy Malibu oil leak & white smoke

This could be due to a number of reasons. The fact white smoke is emitted has nothing to do with overheating. The most likely reason is the burning of an oil based product by the engine. This could have been introduced via the gas tank or carbuerator. ie, an engine or carb cleaner. If no products have been introduced it is possible that the rings in the engine have failed, allowing oil to enter the combustion chamber and being burnt off in the form of exhaust smoke. If this is not checked soon the engine may fail.