Jacko, UN resolutions have authorised action, and never been rescinded. They have no time limit. They are the authorisation used for the past, and continuing, attacks in the no fly-zones.
If these resolutions have no legal basis, then the American adminstration, the British cabinet and the senior military staff at the Pentagon and MOD are already war criminals and, having been accused of such by Iraq, would have been charged. They haven't been. Q.E.D.