Tioccdtr (bug|feature)

[rab at medman.UUCP]

Use of the execute bit on a tty device to indicate write permission
was implemented back in the dark ages at Harvard.  In fact, the
people there (specifically at the Science Center) are forced by the
ingenuity of their students to be so security conscious that they
have had to implement "escape filters" in just about every program
that writes characters to a terminal.  (Imagine a user putting
something nasty in his .plan...)  The people at the Harvard Science
Center have had lots of experience with protection of their UN*X
systems from "hostile" student users.  I'd suggest that you contact
them for details (at least, as much as they're willing to say).