Re: How trustworthy is that I/O device?

Taylor R Campbell <[email protected]> Wed, 6 Nov 2013 22:31:11 +0000

Newsgroups	gmane.os.netbsd.devel.security
Message-ID	<[email protected]>

   Date: Mon, 4 Nov 2013 14:34:37 -0800
   From: Erik Fair <[email protected]>

   All OSes have a problem with USB and potentially all other hot-plug
   I/O busses: can you trust the device that was just plugged into the
   bus? How much I/O do you permit to it before explicit authorization
   of some kind?

I trust memory and assume I/O is arbitrarily broken or adversarial,
and I think this is at least as mistrustful as everyone ought to be.
Naturally, I make mistakes in this model, but I consider them bugs.

Of course, it is difficult to test for a wide variety of broken or
adversarial behaviour, so most of the code paths that get tested are
only the good ones.