Re: Covert Channels

[daw () mozart cs berkeley edu (David Wagner)]

Richard Masoner  wrote:
> Part of covert channel detection, for example, might
> be flagging a user who copies text from an X window
> and pastes that text into an X window that's at a
> lower privilege level.

I wouldn't call that a covert channel; I'd call that an overt channel.
It's just a violation of an information flow style mandatory access
control policy, and not all such violations are covert channels.

(Now if you described a Trojan horse X app leaking text to another program
on the same machine by banging hard on the X server with lots of requests
for a second to send a 1 bit or going idle for a second to send a 0 bit,
that would indeed be a covert channel.  Trying to stop the latter example
is probably futile.)