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DM(8)                     BSD System Manager's Manual                    DM(8)

     dm - dungeon master

     ln -s dm game

     Dm is a program used to regulate game playing.  Dm expects to be invoked
     with the name of a game that a user wishes to play.  This is done by cre-
     ating symbolic links to dm, in the directory /usr/games for all of the
     regulated games.  The actual binaries for these games should be placed in
     a ``hidden'' directory, /usr/games/hide, that may only be accessed by the
     dm program.  Dm determines if the requested game is available and, if so,
     runs it.  The file /etc/dm.conf controls the conditions under which games
     may be run.

     The file /etc/nogames may be used to ``turn off'' game playing.  If the
     file exists, no game playing is allowed; the contents of the file will be
     displayed to any user requesting a game.

     /etc/dm.conf        configuration file
     /etc/nogames        turns off game playing
     /usr/games/hide     directory of ``real'' binaries
     /var/log/games.log  game logging file


     Two problems result from dm running the games setuid ``games''. First,
     all games that allow users to run UNIX commands should carefully set both
     the real and effective user id's immediately before executing those com-
     mands.  Probably more important is that dm never be setuid anything but
     ``games'' so that compromising a game will result only in the user's
     ability to play games at will.  Secondly, games which previously had no
     reason to run setuid and which accessed user files may have to be modi-

     The dm command appeared in 4.3BSD-Tahoe.

4.4BSD                           May 31, 1993                                1