Copyright (c) 1996,1998-2005, 2007 Todd C. Miller Permission to use, copy, modify, and distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies. THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. Sponsored in part by the Defense Advanced Research Projects Agency (DARPA) and Air Force Research Laboratory, Air Force Materiel Command, USAF, under agreement number F39502-99-1-0512. $Sudo: visudo.pod,v 1.38.2.10 2008/02/19 15:45:12 millert Exp $ =pod =head1 NAME visudo - edit the sudoers file =head1 SYNOPSIS B [B<-c>] [B<-q>] [B<-s>] [B<-V>] [B<-f> I] =head1 DESCRIPTION B edits the I file in a safe fashion, analogous to L. B locks the I file against multiple simultaneous edits, provides basic sanity checks, and checks for parse errors. If the I file is currently being edited you will receive a message to try again later. There is a hard-coded list of editors that B will use set at compile-time that may be overridden via the I I C variable. This list defaults to the path to L on your system, as determined by the I script. Normally, B does not honor the C or C environment variables unless they contain an editor in the aforementioned editors list. However, if B is configured with the I<--with-enveditor> flag or the I C variable is set in I, B will use any the editor defines by C or C. Note that this can be a security hole since it allows the user to execute any program they wish simply by setting C or C. B parses the I file after the edit and will not save the changes if there is a syntax error. Upon finding an error, B will print a message stating the line number(s) where the error occurred and the user will receive the "What now?" prompt. At this point the user may enter "e" to re-edit the I file, "x" to exit without saving the changes, or "Q" to quit and save changes. The "Q" option should be used with extreme care because if B believes there to be a parse error, so will B and no one will be able to B again until the error is fixed. If "e" is typed to edit the I file after a parse error has been detected, the cursor will be placed on the line where the error occurred (if the editor supports this feature). =head1 OPTIONS B accepts the following command line options: =over 4 =item -c Enable B mode. The existing I file will be checked for syntax and a message will be printed to the standard output detailing the status of I. If the syntax check completes successfully, B will exit with a value of 0. If a syntax error is encountered, B will exit with a value of 1. =item -f Specify and alternate I file location. With this option B will edit (or check) the I file of your choice, instead of the default, F<@sysconfdir@/sudoers>. The lock file used is the specified I file with ".tmp" appended to it. =item -q Enable B mode. In this mode details about syntax errors are not printed. This option is only useful when combined with the B<-c> flag. =item -s Enable B checking of the I file. If an alias is used before it is defined, B will consider this a parse error. Note that it is not possible to differentiate between an alias and a hostname or username that consists solely of uppercase letters, digits, and the underscore ('_') character. =item -V The B<-V> (version) option causes B to print its version number and exit. =back =head1 ENVIRONMENT The following environment variables are used only if B was configured with the I<--with-env-editor> option: =over 16 =item C Invoked by visudo as the editor to use =item C Used by visudo if VISUAL is not set =back =head1 FILES =over 24 =item F<@sysconfdir@/sudoers> List of who can run what =item F<@sysconfdir@/sudoers.tmp> Lock file for visudo =back =head1 DIAGNOSTICS =over 4 =item sudoers file busy, try again later. Someone else is currently editing the I file. =item @sysconfdir@/sudoers.tmp: Permission denied You didn't run B as root. =item Can't find you in the passwd database Your userid does not appear in the system passwd file. =item Warning: undeclared Alias referenced near ... Either you are using a {User,Runas,Host,Cmnd}_Alias before defining it or you have a user or hostname listed that consists solely of uppercase letters, digits, and the underscore ('_') character. If the latter, you can ignore the warnings (B will not complain). In B<-s> (strict) mode these are errors, not warnings. =item Warning: runas_default set after old value is in use ... You have a I Defaults setting listed in the I file after its value has already been used. This means that entries prior to the I setting will match based on the default value of I (C<@runas_default@>) whereas entries B the I setting will match based on the new value. This is usually unintentional and in most cases the setting should be placed before any C or User specifications. In B<-s> (strict) mode this is an error, not a warning. =back =head1 SEE ALSO L, L, L, L =head1 AUTHOR Many people have worked on I over the years; this version of B was written by: Todd Miller See the HISTORY file in the sudo distribution or visit http://www.sudo.ws/sudo/history.html for more details. =head1 CAVEATS There is no easy way to prevent a user from gaining a root shell if the editor used by B allows shell escapes. =head1 BUGS If you feel you have found a bug in B, please submit a bug report at http://www.sudo.ws/sudo/bugs/ =head1 SUPPORT Limited free support is available via the sudo-users mailing list, see http://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or search the archives. =head1 DISCLAIMER B is provided ``AS IS'' and any express or implied warranties, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose are disclaimed. See the LICENSE file distributed with B or http://www.sudo.ws/sudo/license.html for complete details.