Android has plenty of google's code, and is extremely likely bugged. I'd say that considering recent relevations, folks at NSA have been doing a stellar job of bugging everything and everyone. And I'd struggle to find any reason why one of their "model citizens", google wouldn't bug their OS for them.
Linux in general is a big question mark. On one hand, you can audit code. On the other hand, there's so much of it, and folks working at NSA are best in their field, so injection of specific bugs and backdoors in linux is extremely likely.