From: utzoo!decvax!cca!news@sri-unix
Newsgroups: net.unix-wizards
Title: Re: /dev screwed up
Article-I.D.: sri-unix.2776
Posted: Wed Aug 18 21:49:42 1982
Received: Fri Aug 20 02:10:11 1982

From: greep at RAND-UNIX
Remailed-date: 18 Aug 1982 1920-PDT
Remailed-from: the tty of Geoffrey S. Goodfellow  
Remailed-to: Unix-Wizards@SRI-CSL: ;
Via:  Sri-Csl; 18 Aug 82 21:49-PDT

Date: Sunday,  8 Aug 1982 00:39-PDT
Make sure /dev is write-protected.  Otherwise a common problem is
a program that asks the user for some file name to output to and
then deletes the file (say because it encountered an error which
would make the data useless, or because it is supposed to be
a temporary file).  If the user enters /dev/tty and /dev is writable,
that will do it.  The next user who tries writing to /dev/tty will
cause an ordinary file to be created.  The same goes for /dev/null,
/dev/mt*, etc.

Of course if you have users who do things like this while running
as super user, there's no hope.