1.\" $NetBSD: dm.8,v 1.6 1998/06/08 12:41:41 lukem Exp $ 2.\" 3.\" Copyright (c) 1987, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)dm.8 8.1 (Berkeley) 5/31/93 35.\" 36.Dd May 31, 1993 37.Dt DM 8 38.Os 39.Sh NAME 40.Nm dm 41.Nd dungeon master 42.Sh SYNOPSIS 43.Nm ln 44.Fl s Cm dm Ar game 45.Sh DESCRIPTION 46.Nm 47is a program used to regulate game playing. 48.Nm 49expects to be invoked with the name of a game that a user wishes to play. 50This is done by creating symbolic links to 51.Nm "" , 52in the directory 53.Pa /usr/games 54for all of the regulated games. 55The actual binaries for these games should be placed in a 56.Dq hidden 57directory, 58.Pa /usr/games/hide , 59that may only be accessed by the 60.Nm 61program. 62.Nm 63determines if the requested game is available and, if so, runs it. 64The file 65.Pa /etc/dm.conf 66controls the conditions under which games may 67be run. 68.Pp 69The file 70.Pa /etc/nogames 71may be used to 72.Dq turn off 73game playing. 74If the file exists, no game playing is allowed; the contents of the file 75will be displayed to any user requesting a game. 76.Sh FILES 77.Bl -tag -width /var/log/games.log -compact 78.It Pa /etc/dm.conf 79configuration file 80.It Pa /etc/nogames 81turns off game playing 82.It Pa /usr/games/hide 83directory of ``real'' binaries 84.It Pa /var/log/games.log 85game logging file 86.El 87.Sh SEE ALSO 88.Xr dm.conf 5 89.Sh HISTORY 90The 91.Nm 92command appeared in 93.Bx 4.3 tahoe . 94.Sh SECURITY CONSIDERATIONS 95Two issues result from 96.Nm 97running the games setgid 98.Dq games . 99First, all games that allow users to run 100.Ux 101commands should carefully 102set both the real and effective group id's immediately before executing 103those commands. 104Probably more important is that 105.Nm 106never be setgid anything but 107.Dq games 108so that compromising a game will result only in 109the user's ability to play games at will. 110Secondly, games which previously had no reason to run setgid and which 111accessed user files may have to be modified. 112