Commissioned works wonderfully. They’re only giving permission and direct authorization for Resistance pilots to search their territory for clues to Luke’s location, as well as the tools to travel beyond their own territories for such clues. Anything more than that would be seen by several Senators as an act of war against the First Order, which is what they’re trying to avoid.
Basically, they’re playing the political game. The Republic can tell the First Order that they aren’t fighting against them because they gave supplies to the Resistance under the pretense that it was only to find Luke Skywalker. But Hux is wise enough to realize that the Republic is just using this as an excuse to support them.