SUDO(4)                       Programmer's Manual                      SUDO(4)

NAME
     sudo.conf - configuration for sudo front end

DESCRIPTION
     The sudo.conf file is used to configure the sudo front end.  It specifies
     the security policy and I/O logging plugins, debug flags as well as
     plugin-agnostic path names and settings.

     The sudo.conf file supports the following directives, described in detail
     below.

     Plugin    a security policy or I/O logging plugin

     Path      a plugin-agnostic path

     Set       a front end setting, such as disable__coredump or group__source

     Debug     debug flags to aid in debugging sudo, sudoreplay, visudo, and
               the sudoers plugin.

     The pound sign (`#') is used to indicate a comment.  Both the comment
     character and any text after it, up to the end of the line, are ignored.

     Long lines can be continued with a backslash (`\') as the last character
     on the line.  Note that leading white space is removed from the beginning
     of lines even when the continuation character is used.

     Non-comment lines that don't begin with Plugin, Path, Debug, or Set are
     silently ignored.

     The sudo.conf file is always parsed in the ``C'' locale.

   Plugin configuration
     sudo supports a plugin architecture for security policies and
     input/output logging.  Third parties can develop and distribute their own
     policy and I/O logging plugins to work seamlessly with the sudo front
     end.  Plugins are dynamically loaded based on the contents of sudo.conf.

     A Plugin line consists of the Plugin keyword, followed by the symbol__name
     and the path to the shared object containing the plugin.  The symbol__name
     is the name of the struct policy_plugin or struct io_plugin in the plugin
     shared object.  The path may be fully qualified or relative.  If not
     fully qualified, it is relative to the /usr/local/libexec/sudo directory.
     In other words:

           Plugin sudoers_policy sudoers.so

     is equivalent to:

           Plugin sudoers_policy /usr/local/libexec/sudo/sudoers.so

     Starting with sudo 1.8.5, any additional parameters after the path are
     passed as arguments to the plugin's open function.  For example, to
     override the compile-time default sudoers file mode:

           Plugin sudoers_policy sudoers.so sudoers_mode=0440

     The same shared object may contain multiple plugins, each with a
     different symbol name.  The shared object file must be owned by uid 0 and
     only writable by its owner.  Because of ambiguities that arise from
     composite policies, only a single policy plugin may be specified.  This
     limitation does not apply to I/O plugins.

     If no sudo.conf file is present, or if it contains no Plugin lines, the
     sudoers plugin will be used as the default security policy and for I/O
     logging (if enabled by the policy).  This is equivalent to the following:

           Plugin sudoers_policy sudoers.so
           Plugin sudoers_io sudoers.so

     For more information on the sudo plugin architecture, see the
     sudo_plugin(1m) manual.

   Path settings
     A Path line consists of the Path keyword, followed by the name of the
     path to set and its value.  For example:

           Path noexec /usr/local/libexec/sudo/sudo_noexec.so
           Path askpass /usr/X11R6/bin/ssh-askpass

     The following plugin-agnostic paths may be set in the /etc/sudo.conf
     file:

     askpass   The fully qualified path to a helper program used to read the
               user's password when no terminal is available.  This may be the
               case when sudo is executed from a graphical (as opposed to
               text-based) application.  The program specified by askpass
               should display the argument passed to it as the prompt and
               write the user's password to the standard output.  The value of
               askpass may be overridden by the SUDO_ASKPASS environment
               variable.

     noexec    The fully-qualified path to a shared library containing dummy
               versions of the execv(), execve() and fexecve() library
               functions that just return an error.  This is used to implement
               the noexec functionality on systems that support LD_PRELOAD or
               its equivalent.  The default value is:
               /usr/local/libexec/sudo/sudo__noexec.so.

     sesh      The fully-qualified path to the sesh binary.  This setting is
               only used when sudo is built with SELinux support.  The default
               value is /usr/local/libexec/sudo/sesh.

   Other settings
     The sudo.conf file also supports the following front end settings:

     disable_coredump
               Core dumps of sudo itself are disabled by default.  To aid in
               debugging sudo crashes, you may wish to re-enable core dumps by
               setting ``disable_coredump'' to false in sudo.conf as follows:

                     Set disable_coredump false

               Note that most operating systems disable core dumps from setuid
               programs, including sudo.  To actually get a sudo core file you
               will likely need to enable core dumps for setuid processes.  On
               BSD and Linux systems this is accomplished in the sysctl
               command.  On Solaris, the coreadm command is used to configure
               core dump behavior.

               This setting is only available in sudo version 1.8.4 and
               higher.

     group_source
               sudo passes the invoking user's group list to the policy and
               I/O plugins.  On most systems, there is an upper limit to the
               number of groups that a user may belong to simultaneously
               (typically 16 for compatibility with NFS).  On systems with the
               getconf(1) utility, running:
                     getconf NGROUPS_MAX
               will return the maximum number of groups.

               However, it is still possible to be a member of a larger number
               of groups--they simply won't be included in the group list
               returned by the kernel for the user.  Starting with sudo
               version 1.8.7, if the user's kernel group list has the maximum
               number of entries, sudo will consult the group database
               directly to determine the group list.  This makes it possible
               for the security policy to perform matching by group name even
               when the user is a member of more than the maximum number of
               groups.

               The group__source setting allows the administrator to change
               this default behavior.  Supported values for group__source are:

               static    Use the static group list that the kernel returns.
                         Retrieving the group list this way is very fast but
                         it is subject to an upper limit as described above.
                         It is ``static'' in that it does not reflect changes
                         to the group database made after the user logs in.
                         This was the default behavior prior to sudo 1.8.7.

               dynamic   Always query the group database directly.  It is
                         ``dynamic'' in that changes made to the group
                         database after the user logs in will be reflected in
                         the group list.  On some systems, querying the group
                         database for all of a user's groups can be time
                         consuming when querying a network-based group
                         database.  Most operating systems provide an
                         efficient method of performing such queries.
                         Currently, sudo supports efficient group queries on
                         AIX, BSD, HP-UX, Linux and Solaris.

               adaptive  Only query the group database if the static group
                         list returned by the kernel has the maximum number of
                         entries.  This is the default behavior in sudo 1.8.7
                         and higher.

               For example, to cause sudo to only use the kernel's static list
               of groups for the user:

                     Set group_source static

               This setting is only available in sudo version 1.8.7 and
               higher.

     max_groups
               The maximum number of user groups to retrieve from the group
               database.  This setting is only used when querying the group
               database directly.  It is intended to be used on systems where
               it is not possible to detect when the array to be populated
               with group entries is not sufficiently large.  By default, sudo
               will allocate four times the system's maximum number of groups
               (see above) and retry with double that number if the group
               database query fails.  However, some systems just return as
               many entries as will fit and do not indicate an error when
               there is a lack of space.

               This setting is only available in sudo version 1.8.7 and
               higher.

   Debug flags
     sudo versions 1.8.4 and higher support a flexible debugging framework
     that can help track down what sudo is doing internally if there is a
     problem.

     A Debug line consists of the Debug keyword, followed by the name of the
     program (or plugin) to debug (sudo, visudo, sudoreplay, sudoers), the
     debug file name and a comma-separated list of debug flags.  The debug
     flag syntax used by sudo and the sudoers plugin is subsystem@priority but
     a plugin is free to use a different format so long as it does not include
     a comma (`,').

     For example:

           Debug sudo /var/log/sudo_debug all@warn,plugin@info

     would log all debugging statements at the warn level and higher in
     addition to those at the info level for the plugin subsystem.

     Currently, only one Debug entry per program is supported.  The sudo Debug
     entry is shared by the sudo front end, sudoedit and the plugins.  A
     future release may add support for per-plugin Debug lines and/or support
     for multiple debugging files for a single program.

     The priorities used by the sudo front end, in order of decreasing
     severity, are: crit, err, warn, notice, diag, info, trace and debug.
     Each priority, when specified, also includes all priorities higher than
     it.  For example, a priority of notice would include debug messages
     logged at notice and higher.

     The following subsystems are used by the sudo front-end:

     all         matches every subsystem

     args        command line argument processing

     conv        user conversation

     edit        sudoedit

     exec        command execution

     main        sudo main function

     netif       network interface handling

     pcomm       communication with the plugin

     plugin      plugin configuration

     pty         pseudo-tty related code

     selinux     SELinux-specific handling

     util        utility functions

     utmp        utmp handling

     The sudoers(4) plugin includes support for additional subsystems.

FILES
     /etc/sudo.conf            sudo front end configuration

EXAMPLES
     #
     # Default /etc/sudo.conf file
     #
     # Format:
     #   Plugin plugin_name plugin_path plugin_options ...
     #   Path askpass /path/to/askpass
     #   Path noexec /path/to/sudo_noexec.so
     #   Debug sudo /var/log/sudo_debug all@warn
     #   Set disable_coredump true
     #
     # The plugin_path is relative to /usr/local/libexec/sudo unless
     #   fully qualified.
     # The plugin_name corresponds to a global symbol in the plugin
     #   that contains the plugin interface structure.
     # The plugin_options are optional.
     #
     # The sudoers plugin is used by default if no Plugin lines are
     # present.
     Plugin sudoers_policy sudoers.so
     Plugin sudoers_io sudoers.so

     #
     # Sudo askpass:
     #
     # An askpass helper program may be specified to provide a graphical
     # password prompt for "sudo -A" support.  Sudo does not ship with
     # its own askpass program but can use the OpenSSH askpass.
     #
     # Use the OpenSSH askpass
     #Path askpass /usr/X11R6/bin/ssh-askpass
     #
     # Use the Gnome OpenSSH askpass
     #Path askpass /usr/libexec/openssh/gnome-ssh-askpass

     #
     # Sudo noexec:
     #
     # Path to a shared library containing dummy versions of the execv(),
     # execve() and fexecve() library functions that just return an error.
     # This is used to implement the "noexec" functionality on systems that
     # support C<LD_PRELOAD> or its equivalent.
     # The compiled-in value is usually sufficient and should only be
     # changed if you rename or move the sudo_noexec.so file.
     #
     #Path noexec /usr/local/libexec/sudo/sudo_noexec.so

     #
     # Core dumps:
     #
     # By default, sudo disables core dumps while it is executing
     # (they are re-enabled for the command that is run).
     # To aid in debugging sudo problems, you may wish to enable core
     # dumps by setting "disable_coredump" to false.
     #
     #Set disable_coredump false

     #
     # User groups:
     #
     # Sudo passes the user's group list to the policy plugin.
     # If the user is a member of the maximum number of groups (usually 16),
     # sudo will query the group database directly to be sure to include
     # the full list of groups.
     #
     # On some systems, this can be expensive so the behavior is configurable.
     # The "group_source" setting has three possible values:
     #   static   - use the user's list of groups returned by the kernel.
     #   dynamic  - query the group database to find the list of groups.
     #   adaptive - if user is in less than the maximum number of groups.
     #              use the kernel list, else query the group database.
     #
     #Set group_source static

SEE ALSO
     sudoers(4), sudo(1m), sudo_plugin(1m)

HISTORY
     See the HISTORY file in the sudo distribution
     (http://www.sudo.ws/sudo/history.html) for a brief history of sudo.

AUTHORS
     Many people have worked on sudo over the years; this version consists of
     code written primarily by:

           Todd C. Miller

     See the CONTRIBUTORS file in the sudo distribution
     (http://www.sudo.ws/sudo/contributors.html) for an exhaustive list of
     people who have contributed to sudo.

BUGS
     If you feel you have found a bug in sudo, please submit a bug report at
     http://www.sudo.ws/sudo/bugs/

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.

DISCLAIMER
     sudo 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 sudo or http://www.sudo.ws/sudo/license.html for
     complete details.

Sudo 1.8.7                      March 14, 2013                      Sudo 1.8.7
