nologin.tproj/nologin.5

   1 .\" Copyright (c) 1993
   2 .\"     The Regents of the University of California.  All rights reserved.
   3 .\"
   4 .\" Redistribution and use in source and binary forms, with or without
   5 .\" modification, are permitted provided that the following conditions
   6 .\" are met:
   7 .\" 1. Redistributions of source code must retain the above copyright
   8 .\"    notice, this list of conditions and the following disclaimer.
   9 .\" 2. Redistributions in binary form must reproduce the above copyright
  10 .\"    notice, this list of conditions and the following disclaimer in the
  11 .\"    documentation and/or other materials provided with the distribution.
  12 .\" 4. Neither the name of the University nor the names of its contributors
  13 .\"    may be used to endorse or promote products derived from this software
  14 .\"    without specific prior written permission.
  15 .\"
  16 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  17 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19 .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  20 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26 .\" SUCH DAMAGE.
  27 .\"
  28 .\"     @(#)nologin.8   8.1 (Berkeley) 6/19/93
  29 .\" $FreeBSD: src/usr.sbin/nologin/nologin.5,v 1.15 2007/05/10 11:22:24 yar Exp $
  30 .\"
  31 .Dd May 10, 2007
  32 .Dt NOLOGIN 5
  33 .Os
  34 .Sh NAME
  35 .Nm nologin
  36 .Nd disallow logins
  37 .Sh DESCRIPTION
  38 Programs such as
  39 .Xr login 1
  40 disallow logins if the
  41 .Nm
  42 file exists.
  43 The programs display the contents of
  44 .Nm
  45 to the user if possible and interrupt the login sequence.
  46 This makes it simple to temporarily prevent incoming logins systemwide.
  47 .Pp
  48 To disable logins on a per-account basis,
  49 investigate
  50 .Xr nologin 8 .
  51 .Sh SECURITY
  52 The
  53 .Nm
  54 file is ignored for user root by default.
  55 .Sh IMPLEMENTATION NOTES
  56 The
  57 .Nm
  58 feature is implemented through
  59 .Xr login.conf 5 ,
  60 which allows to change the pathname of the
  61 file and to extend the list of users
  62 exempt from temporary login restriction.
  63 .Pp
  64 PAM-aware programs can be selectively configured to respect
  65 .Nm
  66 using the
  67 .Xr pam_nologin 8
  68 module via
  69 .Xr pam.conf 5 .
  70 .Pp
  71 The
  72 .Nm
  73 file will be removed at system boot if it resides in
  74 .Pa /var/run
  75 and
  76 .Va cleanvar_enable
  77 is set to
  78 .Dq Li YES
  79 in
  80 .Xr rc.conf 5 ,
  81 which is default.
  82 Therefore system reboot can effectively re-enable logins.
  83 .Sh FILES
  84 .Bl -tag -width ".Pa /var/run/nologin" -compact
  85 .It Pa /var/run/nologin
  86 default location of
  87 .Nm
  88 .El
  89 .Sh SEE ALSO
  90 .Xr login 1 ,
  91 .Xr login.conf 5 ,
  92 .Xr pam.conf 5 ,
  93 .Xr rc.conf 5 ,
  94 .Xr nologin 8 ,
  95 .Xr pam_nologin 8 ,
  96 .Xr shutdown 8