Unfortunately, NASA has to follow ITAR, which means that a lot of stuff has to be kept closed - for example, basically anything on the topic of computational fluid dynamics (e.g. [0]). US persons can request a copy of much of this software, but they have to sign an agreement with NASA promising not to redistribute it without NASA's permission.
Are China, Russia, North Korea, Iran, al Qaeda, ISIS, really disadvantaged by not being able to access NASA's CFD software? I'm sure the nation-states have the money and people to work it out for themselves, whereas the non-state actors wouldn't know what to do with it.