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From: pfalstad@phoenix.princeton.edu (Paul Falstad)
Newsgroups: comp.unix.wizards
Subject: Re: BSD tty security, part 3: How to Fix It
Message-ID: <67264@willbeavax.Princeton.EDU>
Date: 4 May 91 23:32:55 GMT
References: <12535@dog.ee.lbl.gov> <73525@eerie.acsu.Buffalo.EDU> <235@harem.clydeunix.com>
Sender: gnus@idunno.Princeton.EDU
Organization: League For Fighting Chartered Accountancy
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wes@harem.clydeunix.com (Wes Peters) wrote:
>I think write should reject any input not from a terminal:

>    if (!isatty(fileno(stdin))) {
>        fprintf(stderr, "write: input must be a terminal!\n");

>I know this will take care of 'cat longfile | write sucker', but does it
>also take care of a 'here is' document (i.e. shell << document)?

Yes, but it doesn't take care of this:

   cat longfile | pty write sucker

--
              Paul Falstad  pfalstad@phoenix.princeton.edu
         And on the roads, too, vicious gangs of KEEP LEFT signs!
     If Princeton knew my opinions, they'd have expelled me long ago.