The story does not tell us how Linus Torvalds responded to the NSA, but I’m guessing he told them he wouldn’t be able to inject backdoors even if he wanted to, since the source code is open, and all changes to it are reviewed by many independent people.
Yeah I'm guessing the answer would be more colorful based on the historical data we have
There aren't enough swear-words in the English language, so now I'll have to call you perkeleen vittupää just to express my disgust and frustration with this crap.
Also experience shows that it's possible to backdoor software in very subtle ways that could go years without anyone spotting them. So if he had decided to he probably could have done it, despite Linux being open source.