sudo.conf --- configuration for sudo front end


     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

     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 dynamic shared object that contains the plugin.  The
     symbol_name is the name of the struct policy_plugin or struct io_plugin
     symbol contained in the plugin.  The path may be fully qualified or
     relative.  If not fully qualified, it is relative to the directory
     specified by the plugin_dir Path setting, which defaults to
     /usr/lib/sudo.  In other words:

       Plugin sudoers_policy

     is equivalent to:

       Plugin sudoers_policy /usr/lib/sudo/

     If the plugin was compiled statically into the sudo binary instead of
     being installed as a dynamic shared object, the path should be specified
     without a leading directory, as it does not actually exist in the file
     system.  For example:

       Plugin sudoers_policy

     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_mode=0440

     The same dynamic shared object may contain multiple plugins, each with a
     different symbol name.  The 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
       Plugin sudoers_io

     For more information on the sudo plugin architecture, see the
     sudo_plugin(8) 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/lib/sudo/
       Path askpass /usr/X11R6/bin/ssh-askpass

     If no path name is specified, features relying on the specified setting
     will be disabled.  Disabling Path settings is only supported in sudo
     version 1.8.16 and higher.

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

     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

     noexec    The fully-qualified path to a shared library containing dummy
           versions of the execl(), execle(), execlp(), exect(), execv(),
           execve(), execvP(), execvp(), execvpe(), fexecve(), popen(),
           posix_spawn(), posix_spawnp(), and system() 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:

           The default directory to use when searching for plugins that
           are specified without a fully qualified path name.  The default
           value is /usr/lib/sudo.

     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/lib/sudo/sesh.

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

           Core dumps of sudo itself are disabled by default to prevent
           the disclosure of potentially sensitive information.  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

           All modern operating systems place restrictions on core dumps
           from setuid processes like sudo so this option can be enabled
           without compromising security.  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

           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

           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

           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

           The maximum number of user groups to retrieve from the group
           database.  Values less than one will be ignored.  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

           By default, sudo will probe the system's network interfaces and
           pass the IP address of each enabled interface to the policy
           plugin.  This makes it possible for the plugin to match rules
           based on the IP address without having to query DNS.  On Linux
           systems with a large number of virtual interfaces, this may
           take a non-negligible amount of time.  If IP-based matching is
           not required, network interface probing can be disabled as

                 Set probe_interfaces false

           This setting is only available in sudo version 1.8.10 and

   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

     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.

     As of sudo 1.8.12, multiple Debug entries may be specified per program.
     Older versions of sudo only support a single Debug entry per program.
     Plugin-specific Debug entries are also supported starting with sudo
     1.8.12 and are matched by either the base name of the plugin that was
     loaded (for example or by the plugin's fully-qualified path
     name.  Previously, the sudoers plugin shared the same Debug entry as the
     sudo front end and could not be configured separately.

     The following priorities are supported, in order of decreasing severity:
     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 priorities trace and debug also include function call tracing which
     logs when a function is entered and when it returns.  For example, the
     following trace is for the get_user_groups() function located in

       sudo[123] -> get_user_groups @ src/sudo.c:385
       sudo[123] <- get_user_groups @ src/sudo.c:429 := groups=10,0,5

     When the function is entered, indicated by a right arrow '->', the
     program, process ID, function, source file and line number are logged.
     When the function returns, indicated by a left arrow '<-', the same
     information is logged along with the return value.  In this case, the
     return value is a string.

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

     all         matches every subsystem

     args        command line argument processing

     conv        user conversation

     edit        sudoedit

     event       event subsystem

     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(5) plugin includes support for additional subsystems.


     /etc/sudo.conf            sudo front end configuration


     # Default /etc/sudo.conf file
     # Format:
     #   Plugin plugin_name plugin_path plugin_options ...
     #   Path askpass /path/to/askpass
     #   Path noexec /path/to/
     #   Debug sudo /var/log/sudo_debug all@warn
     #   Set disable_coredump true
     # The plugin_path is relative to /usr/lib/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
     Plugin sudoers_io

     # 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 file.
     #Path noexec /usr/lib/sudo/

     # 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


     sudoers(5), sudo(8), sudo_plugin(8)


     See the HISTORY file in the sudo distribution
     ( for a brief history of sudo.


     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
     ( for an exhaustive list of people
     who have contributed to sudo.


     If you feel you have found a bug in sudo, please submit a bug report at


     Limited free support is available via the sudo-users mailing list, see to subscribe or search
     the archives.


     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 for
     complete details.


Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.

Free Software

Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.

Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.

Free Books

The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.

Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.

Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.