# sudo.conf

## NAME



           **sudo.conf** — configuration for sudo front-end
    


## DESCRIPTION



           The **sudo.conf** file is used to configure the **sudo** front-end.  It is
           used to configure sudo plugins, plugin-agnostic path names, debug
           flags, and other settings.
    
           The **sudo.conf** file supports the following directives, described in
           detail below.
    
           Plugin  an approval, audit, I/O logging, or security policy 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.  Leading white space is removed from the
           beginning of lines even when a 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_
           _approval_plugin_ , _struct audit_plugin_ , _struct io_plugin_ , or _struct_
           _policy_plugin_ defined by the plugin.  If a plugin implements
           multiple plugin types, there must be a _Plugin_ line for each unique
           symbol name.  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/local/libexec/sudo_.  In other words:
    
               Plugin sudoers_policy sudoers.so
    
           is equivalent to:
    
               Plugin sudoers_policy /usr/local/libexec/sudo/sudoers.so
    
           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 sudoers.so
    
           On AIX systems, the plugin may be either a shared object ending in
           ‘.so’ or an archive file containing a shared object ending in ‘.a’
           with the name of the shared object in parentheses at the end.
    
           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
    
           See the _sudoers_(5) manual for a list of supported arguments.
    
           The same dynamic shared object may contain multiple plugins, each
           with a different symbol name.  The file must be owned by user-ID 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, for I/O logging (if enabled by the policy), and for
           auditing.  This is equivalent to the following:
    
               Plugin sudoers_policy sudoers.so
               Plugin sudoers_io sudoers.so
               Plugin sudoers_audit sudoers.so
    
           Starting with **sudo** version 1.9.1, some of the logging
           functionality of the **sudoers** plugin has been moved from the policy
           plugin to an audit plugin.  To maintain compatibility with
           **sudo.conf** files from older **sudo** versions, if **sudoers** is configured
           as the security policy, it will be used as an audit plugin as
           well.  This guarantees that the logging behavior will be
           consistent with that of **sudo** versions 1.9.0 and below.
    
           For more information on the **sudo** plugin architecture, see the
           _sudo_plugin_(5) 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 intercept /usr/local/libexec/sudo/sudo_intercept.so
               Path noexec /usr/local/libexec/sudo/sudo_noexec.so
               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_ 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.
    
           devsearch
                 An ordered, colon-separated search path of directories to
                 look in for device nodes.  This is used when mapping the
                 process's tty device number to a device name on systems that
                 do not provide such a mechanism.  Sudo will _not_ recurse into
                 sub-directories.  If terminal devices may be located in a
                 sub-directory of _/dev_ , that path must be explicitly listed
                 in _devsearch_.  The default value is
                 _/dev/pts:/dev/vt:/dev/term:/dev/zcons:/dev/pty:/dev_
    
                 This option is ignored on systems that support either the
                 **devname**() or **_ttyname_dev**() functions, for example BSD,
                 macOS and Solaris.
    
           intercept
                 The path to a shared library containing wrappers for the
                 _execve_(2), _execl_(3), _execle_(3), _execlp_(3), _execv_(3),
                 _execvp_(3), _execvpe_(3), and _system_(3) library functions that
                 intercepts attempts to run further commands and performs a
                 policy check before allowing them to be executed.  This is
                 used to implement the _intercept_ and _log_subcmds_
                 functionality on systems that support LD_PRELOAD or the
                 equivalent.
    
                 The _intercept_ path may be set to either a single fully-
                 qualified path, or, for systems that support separate
                 LD_PRELOAD environment variables for 32-bit and 64-bit
                 executables, it may optionally be set to two fully-qualified
                 paths separated by a colon (‘:’).  The first path should be
                 the 32-bit version and the second the 64-bit version.  This
                 two-path form is currently only supported on AIX and Solaris
                 systems.  The default value is
                 _/usr/local/libexec/sudo/sudo_intercept.so_.
    
           noexec
                 The path to a shared library containing wrappers for the
                 _execve_(2), _execl_(3), _execle_(3), _execlp_(3), _exect_(3),
                 _execv_(3), _execveat_(3), _execvP_(3), _execvp_(3), _execvpe_(3),
                 _fexecve_(3), _popen_(3), _posix_spawn_(3), _posix_spawnp_(3),
                 _system_(3), and _wordexp_(3) library functions that prevent the
                 execution of further commands.  This is used to implement
                 the _noexec_ functionality on systems that support LD_PRELOAD
                 or the equivalent.
    
                 The _noexec_ path may be set to either a single fully-
                 qualified path, or, for systems that support separate
                 LD_PRELOAD environment variables for 32-bit and 64-bit
                 executables, it may optionally be set to two fully-qualified
                 paths separated by a colon (‘:’).  The first path should be
                 the 32-bit version and the second the 64-bit version.  This
                 two-path form is currently only supported on AIX and Solaris
                 systems.  The default value is
                 _/usr/local/libexec/sudo/sudo_noexec.so_.
    
           plugin_dir
                 The default directory to use when searching for plugins that
                 are specified without a fully-qualified path name.  The
                 default value is _/usr/local/libexec/sudo_.
    
       **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 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 set-user-ID 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 set-user-ID processes.  On BSD and Linux systems
                 this is accomplished in the _sysctl_(8) command.  On Solaris,
                 the _coreadm_(1m) 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, Linux, macOS, and
                       Solaris.  This is the default behavior on macOS in
                       **sudo** 1.9.6 and higher.
    
                 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 on systems
                       other than macOS 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.  Values less than one or larger than 1024 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.
    
                 This setting is only available in **sudo** version 1.8.7 and
                 higher.  It should not be required in **sudo** versions 1.8.24
                 and higher and may be removed in a later release.
    
           probe_interfaces
                 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 follows:
    
                     Set probe_interfaces false
    
                 This setting is only available in **sudo** version 1.8.10 and
                 higher.
    
       **Debug settings**
           **sudo** versions 1.8.4 and higher support a flexible debugging
           framework that can log 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, plugin, or shared object to debug, the debug file
           name, and a comma-separated list of debug flags.  The debug flag
           syntax used by **sudo** , the **sudoers** plugin along with its associated
           programs and shared objects is _subsystem_ @_priority_ but a third-
           party plugin is free to use a different format so long as it does
           not include a comma (‘,’).
    
           On AIX systems, a _Debug_ line will match a plugin specified as
           either the name of an SVR4-style shared object file ending in
           ‘.so’, an archive file ending in ‘.a’, or an archive file ending
           in ‘.a’ with the name of the shared object in parentheses.
    
           Examples:
    
               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.
    
               Debug sudo_intercept.so /var/log/intercept_debug all@debug
    
           would log all debugging statements, regardless of level, for the
           _sudo_intercept.so_ shared library that implements **sudo** 's intercept
           functionality on some systems.
    
               Debug sudoers.so /var/log/sudoers_debug all@debug
    
           would log all debugging statements, regardless of level, for the
           **sudoers** plugin.  See _sudoers_(5) for the full list of subsystems
           supported by the **sudoers** plugin.
    
           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 _sudoers.so_) 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 src/sudo.c:
    
               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-terminal related code
    
           _selinux_     SELinux-specific handling
    
           _util_        utility functions
    
           _utmp_        utmp handling
    
           The _sudoers_(5) plugin includes support for additional subsystems.
    


## FILES



           _/etc/sudo.conf_            **sudo** front-end configuration
    


## EXAMPLES



           #
           # Default /etc/sudo.conf file
           #
           # Sudo plugins:
           #   Plugin plugin_name plugin_path plugin_options ...
           #
           # 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
           #Plugin sudoers_audit sudoers.so
    
           #
           # Sudo askpass:
           #   Path askpass /path/to/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 device search path:
           #   Path devsearch /dev/path1:/dev/path2:/dev
           #
           # A colon-separated list of paths to check when searching for a user's
           # terminal device.
           #
           #Path devsearch /dev/pts:/dev/vt:/dev/term:/dev/zcons:/dev/pty:/dev
    
           #
           # Sudo command interception:
           #   Path intercept /path/to/sudo_intercept.so
           #
           # Path to a shared library containing replacements for the execv(),
           # execve() and fexecve() library functions, which perform a policy
           # check to verify whether the command is allowed and simply return
           # an error if it is not.  This is used to implement the "intercept"
           # functionality on systems that support LD_PRELOAD or its equivalent.
           #
           # The compiled-in value is usually sufficient and should only be changed
           # if you rename or move the sudo_intercept.so file.
           #
           #Path intercept /usr/local/libexec/sudo/sudo_intercept.so
    
           #
           # Sudo noexec:
           #   Path noexec /path/to/sudo_noexec.so
           #
           # Path to a shared library containing replacements for the execv()
           # family of 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 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
    
           #
           # Sudo plugin directory:
           #   Path plugin_dir /path/to/plugins
           #
           # The default directory to use when searching for plugins that are
           # specified without a fully-qualified path name.
           #
           #Path plugin_dir /usr/local/libexec/sudo
    
           #
           # Core dumps:
           #   Set disable_coredump true|false
           #
           # 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:
           #   Set group_source static|dynamic|adaptive
           #
           # 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
    
           #
           # Sudo interface probing:
           #   Set probe_interfaces true|false
           #
           # By default, sudo will probe the system's network interfaces and
           # pass the IP address of each enabled interface to the policy plugin.
           # On systems with a large number of virtual interfaces this may take
           # a noticeable amount of time.
           #
           #Set probe_interfaces false
    
           #
           # Sudo debug files:
           #   Debug program /path/to/debug_log subsystem@priority[,subsyste@priority]
           #
           # Sudo and related programs support logging debug information to a file.
           # The program is typically sudo, sudoers.so, sudoreplay, or visudo.
           #
           # Subsystems vary based on the program; "all" matches all subsystems.
           # Priority may be crit, err, warn, notice, diag, info, trace, or debug.
           # Multiple subsystem@priority may be specified, separated by a comma.
           #
           #Debug sudo /var/log/sudo_debug all@debug
           #Debug sudoers.so /var/log/sudoers_debug all@debug
    


## BUGS



           If you believe you have found a bug in **sudo.conf** , you can either
           file a bug report in the sudo bug database,
           https://bugzilla.sudo.ws/, or open an issue at
           https://github.com/sudo-project/sudo/issues.  If you would prefer
           to use email, messages may be sent to the sudo-workers mailing
           list, https://www.sudo.ws/mailman/listinfo/sudo-workers (public)
           or <sudo@sudo.ws> (private).
    
           Please do not report security vulnerabilities through public
           GitHub issues, Bugzilla or mailing lists.  Instead, report them
           via email to <Todd.Miller@sudo.ws>.  You may encrypt your message
           with PGP if you would like, using the key found at
           https://www.sudo.ws/dist/PGPKEYS.
    


## SUPPORT



           Limited free support is available via the sudo-users mailing list,
           see https://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.md file distributed with **sudo** or
           https://www.sudo.ws/about/license/ for complete details.
    


* * *