Now, having kissed your back sides

There is currently a thread on the GB about the CP3 trade to the Lakers being nixed by David Stern. Comments have been made about Stern overstepping his authority, and I brought up the point that all trades must meet league approval. My understanding of the deal at the time, is that there are grey areas in the CBA that are either partially covered or not covered at all, which explains the language " All trades must meet league approval."
So my question is whether or not that is correct. Are there grey areas in which the commissioner has the authority to veto any trade, or are there specific regulations that govern any and all trades? Keep in mind I'd like answers that include current CBA rules, but more specifically, the rules that were relevant during the time Stern vetoed the CP3 to Lakers deal.
Thank you so much for your input.
