I don't think we know that - not in either direction. The rebels could have launched from near the base. The Syrian government could have ordered the launch from their base. Or a Syrian rebel remaining as an agent in place may have coordinated a launch without authorization from a Syrian base, possibly while those executing his orders believed the launch was authorized. Unless we have clear communications intercepts, which to my knowledge have not been released, we cannot know the truth. All I know is that all sides - the Assad government, the rebels, and the liar in our White House - are untrustworthy.
Ping
I am still digging on this one, nothing I mean nothing is leaked by MASSAD agents unless it has a purpose. Nice way to get someone to eliminate the threat of the stockpiles. Then a quick cleanup of the rebel groups by a few Spec Ops groups and we have a safer world. Only problem is we are arming the bad guys.