Comment 8 for bug 102408

An external app can't read the pipes or sockets. I'm not sure how much
of a problem that is but I certainly don't want to find out.

Yes, there are many ways to get screwed. I just prefer to eliminate as
many as possible. Armor plating is nice.

And no, I don't trust helper apps or anything else that isn't guaranteed
bug free. I've been burned too often.

Take a look at bug 125505. There I proposed a mime assistant that could
execv the real helper. You could use the same idea to sanitize the
helper environment. It would be a lot faster than fixing all of mozilla.