SUDOERS(5)                NetBSD File Formats Manual                SUDOERS(5)

NAME
     sudoers -- default sudo security policy plugin

DESCRIPTION
     The sudoers policy plugin determines a user's sudo privileges.  It is the
     default sudo policy plugin.  The policy is driven by the /etc/sudoers
     file or, optionally in LDAP.  The policy format is described in detail in
     the SUDOERS FILE FORMAT section.  For information on storing sudoers pol-
     icy information in LDAP, please see sudoers.ldap(5).

   Configuring sudo.conf for sudoers
     sudo consults the sudo.conf(5) file to determine which policy and and I/O
     logging plugins to load.  If no sudo.conf(5) file is present, or if it
     contains no Plugin lines, sudoers will be used for policy decisions and
     I/O logging.  To explicitly configure sudo.conf(5) to use the sudoers
     plugin, the following configuration can be used.

           Plugin sudoers_policy sudoers.so
           Plugin sudoers_io sudoers.so

     Starting with sudo 1.8.5, it is possible to specify optional arguments to
     the sudoers plugin in the sudo.conf(5) file.  These arguments, if
     present, should be listed after the path to the plugin (i.e. after
     sudoers.so).  Multiple arguments may be specified, separated by white
     space.  For example:

           Plugin sudoers_policy sudoers.so sudoers_mode=0400

     The following plugin arguments are supported:

     ldap_conf=pathname
               The ldap_conf argument can be used to override the default path
               to the ldap.conf file.

     ldap_secret=pathname
               The ldap_secret argument can be used to override the default
               path to the ldap.secret file.

     sudoers_file=pathname
               The sudoers_file argument can be used to override the default
               path to the sudoers file.

     sudoers_uid=uid
               The sudoers_uid argument can be used to override the default
               owner of the sudoers file.  It should be specified as a numeric
               user ID.

     sudoers_gid=gid
               The sudoers_gid argument can be used to override the default
               group of the sudoers file.  It must be specified as a numeric
               group ID (not a group name).

     sudoers_mode=mode
               The sudoers_mode argument can be used to override the default
               file mode for the sudoers file.  It should be specified as an
               octal value.

     For more information on configuring sudo.conf(5), please refer to its
     manual.

   User Authentication
     The sudoers security policy requires that most users authenticate them-
     selves before they can use sudo.  A password is not required if the
     invoking user is root, if the target user is the same as the invoking
     user, or if the policy has disabled authentication for the user or com-
     mand.  Unlike su(1), when sudoers requires authentication, it validates
     the invoking user's credentials, not the target user's (or root's) cre-
     dentials.  This can be changed via the rootpw, targetpw and runaspw
     flags, described later.

     If a user who is not listed in the policy tries to run a command via
     sudo, mail is sent to the proper authorities.  The address used for such
     mail is configurable via the mailto Defaults entry (described later) and
     defaults to root.

     Note that no mail will be sent if an unauthorized user tries to run sudo
     with the -l or -v option unless there is an authentication error and
     either the mail_always or mail_badpass flags are enabled.  This allows
     users to determine for themselves whether or not they are allowed to use
     sudo.  All attempts to run sudo (successful or not) will be logged,
     regardless of whether or not mail is sent.

     If sudo is run by root and the SUDO_USER environment variable is set, the
     sudoers policy will use this value to determine who the actual user is.
     This can be used by a user to log commands through sudo even when a root
     shell has been invoked.  It also allows the -e option to remain useful
     even when invoked via a sudo-run script or program.  Note, however, that
     the sudoers file lookup is still done for root, not the user specified by
     SUDO_USER.

     sudoers uses per-user time stamp files for credential caching.  Once a
     user has been authenticated, a record is written containing the uid that
     was used to authenticate, the terminal session ID, and a time stamp
     (using a monotonic clock if one is available).  The user may then use
     sudo without a password for a short period of time (5 minutes unless
     overridden by the timestamp_timeout option).  By default, sudoers uses a
     separate record for each tty, which means that a user's login sessions
     are authenticated separately.  The tty_tickets option can be disabled to
     force the use of a single time stamp for all of a user's sessions.

   Logging
     sudoers can log both successful and unsuccessful attempts (as well as
     errors) to syslog(3), a log file, or both.  By default, sudoers will log
     via syslog(3) but this is changeable via the syslog and logfile Defaults
     settings.  See LOG FORMAT for a description of the log file format.

     sudoers is also capable of running a command in a pseudo-tty and logging
     all input and/or output.  The standard input, standard output and stan-
     dard error can be logged even when not associated with a terminal.  I/O
     logging is not on by default but can be enabled using the log_input and
     log_output options as well as the LOG_INPUT and LOG_OUTPUT command tags.
     See I/O LOG FILES for details on how I/O log files are stored.

   Command environment
     Since environment variables can influence program behavior, sudoers pro-
     vides a means to restrict which variables from the user's environment are
     inherited by the command to be run.  There are two distinct ways sudoers
     can deal with environment variables.

     By default, the env_reset option is enabled.  This causes commands to be
     executed with a new, minimal environment.  On AIX (and Linux systems
     without PAM), the environment is initialized with the contents of the
     /etc/environment file.  On BSD systems, if the use_loginclass option is
     enabled, the environment is initialized based on the path and setenv set-
     tings in /etc/login.conf.  The new environment contains the TERM, PATH,
     HOME, MAIL, SHELL, LOGNAME, USER, USERNAME and SUDO_* variables in addi-
     tion to variables from the invoking process permitted by the env_check
     and env_keep options.  This is effectively a whitelist for environment
     variables.  Environment variables with a value beginning with () are
     removed unless both the name and value parts are matched by env_keep or
     env_check, as they will be interpreted as functions by older versions of
     the bash shell.  Prior to version 1.8.11, such variables were always
     removed.

     If, however, the env_reset option is disabled, any variables not explic-
     itly denied by the env_check and env_delete options are inherited from
     the invoking process.  In this case, env_check and env_delete behave like
     a blacklist.  Environment variables with a value beginning with () are
     always removed, even if they do not match one of the blacklists.  Since
     it is not possible to blacklist all potentially dangerous environment
     variables, use of the default env_reset behavior is encouraged.

     By default, environment variables are matched by name.  However, if the
     pattern includes an equal sign (`='), both the variables name and value
     must match.  For example, an old-style (pre-shellshock) bash shell func-
     tion could be matched as follows:

         env_keep += "my_func=()*"

     Without the ``=()*'' suffix, this would not match, as old-style bash
     shell functions are not preserved by default.

     The complete list of environment variables that sudo allows or denies is
     contained in the output of ``sudo -V'' when run as root.  Please note
     that this list varies based on the operating system sudo is running on.

     On systems that support PAM where the pam_env module is enabled for sudo,
     variables in the PAM environment may be merged in to the environment.  If
     a variable in the PAM environment is already present in the user's envi-
     ronment, the value will only be overridden if the variable was not pre-
     served by sudoers.  When env_reset is enabled, variables preserved from
     the invoking user's environment by the env_keep list take precedence over
     those in the PAM environment.  When env_reset is disabled, variables
     present the invoking user's environment take precedence over those in the
     PAM environment unless they match a pattern in the env_delete list.

     Note that the dynamic linker on most operating systems will remove vari-
     ables that can control dynamic linking from the environment of setuid
     executables, including sudo.  Depending on the operating system this may
     include _RLD*, DYLD_*, LD_*, LDR_*, LIBPATH, SHLIB_PATH, and others.
     These type of variables are removed from the environment before sudo even
     begins execution and, as such, it is not possible for sudo to preserve
     them.

     As a special case, if sudo's -i option (initial login) is specified,
     sudoers will initialize the environment regardless of the value of
     env_reset.  The DISPLAY, PATH and TERM variables remain unchanged; HOME,
     MAIL, SHELL, USER, and LOGNAME are set based on the target user.  On AIX
     (and Linux systems without PAM), the contents of /etc/environment are
     also included.  On BSD systems, if the use_loginclass flag is enabled,
     the path and setenv variables in /etc/login.conf are also applied.  All
     other environment variables are removed.

     Finally, the restricted_env_file and env_file files are applied, if
     present.  The variables in restricted_env_file are applied first and are
     subject to the same restrictions as the invoking user's environment, as
     detailed above.  The variables in env_file are applied last and are not
     subject to these restrictions.  In both cases, variables present in the
     files will only be set to their specified values if they would not con-
     flict with an existing environment variable.

SUDOERS FILE FORMAT
     The sudoers file is composed of two types of entries: aliases (basically
     variables) and user specifications (which specify who may run what).

     When multiple entries match for a user, they are applied in order.  Where
     there are multiple matches, the last match is used (which is not neces-
     sarily the most specific match).

     The sudoers file grammar will be described below in Extended Backus-Naur
     Form (EBNF).  Don't despair if you are unfamiliar with EBNF; it is fairly
     simple, and the definitions below are annotated.

   Quick guide to EBNF
     EBNF is a concise and exact way of describing the grammar of a language.
     Each EBNF definition is made up of production rules.  E.g.,

     symbol ::= definition | alternate1 | alternate2 ...

     Each production rule references others and thus makes up a grammar for
     the language.  EBNF also contains the following operators, which many
     readers will recognize from regular expressions.  Do not, however, con-
     fuse them with ``wildcard'' characters, which have different meanings.

     ?     Means that the preceding symbol (or group of symbols) is optional.
           That is, it may appear once or not at all.

     *     Means that the preceding symbol (or group of symbols) may appear
           zero or more times.

     +     Means that the preceding symbol (or group of symbols) may appear
           one or more times.

     Parentheses may be used to group symbols together.  For clarity, we will
     use single quotes ('') to designate what is a verbatim character string
     (as opposed to a symbol name).

   Aliases
     There are four kinds of aliases: User_Alias, Runas_Alias, Host_Alias and
     Cmnd_Alias.

     Alias ::= 'User_Alias'  User_Alias (':' User_Alias)* |
               'Runas_Alias' Runas_Alias (':' Runas_Alias)* |
               'Host_Alias'  Host_Alias (':' Host_Alias)* |
               'Cmnd_Alias'  Cmnd_Alias (':' Cmnd_Alias)*

     User_Alias ::= NAME '=' User_List

     Runas_Alias ::= NAME '=' Runas_List

     Host_Alias ::= NAME '=' Host_List

     Cmnd_Alias ::= NAME '=' Cmnd_List

     NAME ::= [A-Z]([A-Z][0-9]_)*

     Each alias definition is of the form

     Alias_Type NAME = item1, item2, ...

     where Alias_Type is one of User_Alias, Runas_Alias, Host_Alias, or
     Cmnd_Alias.  A NAME is a string of uppercase letters, numbers, and under-
     score characters (`_').  A NAME must start with an uppercase letter.  It
     is possible to put several alias definitions of the same type on a single
     line, joined by a colon (`:').  E.g.,

     Alias_Type NAME = item1, item2, item3 : NAME = item4, item5

     It is a syntax error to redefine an existing alias.  It is possible to
     use the same name for aliases of different types, but this is not recom-
     mended.

     The definitions of what constitutes a valid alias member follow.

     User_List ::= User |
                   User ',' User_List

     User ::= '!'* user name |
              '!'* #uid |
              '!'* %group |
              '!'* %#gid |
              '!'* +netgroup |
              '!'* %:nonunix_group |
              '!'* %:#nonunix_gid |
              '!'* User_Alias

     A User_List is made up of one or more user names, user IDs (prefixed with
     `#'), system group names and IDs (prefixed with `%' and `%#' respec-
     tively), netgroups (prefixed with `+'), non-Unix group names and IDs
     (prefixed with `%:' and `%:#' respectively) and User_Aliases. Each list
     item may be prefixed with zero or more `!' operators.  An odd number of
     `!' operators negate the value of the item; an even number just cancel
     each other out.  User netgroups are matched using the user and domain
     members only; the host member is not used when matching.

     A user name, uid, group, gid, netgroup, nonunix_group or nonunix_gid may
     be enclosed in double quotes to avoid the need for escaping special char-
     acters.  Alternately, special characters may be specified in escaped hex
     mode, e.g. \x20 for space.  When using double quotes, any prefix charac-
     ters must be included inside the quotes.

     The actual nonunix_group and nonunix_gid syntax depends on the underlying
     group provider plugin.  For instance, the QAS AD plugin supports the fol-
     lowing formats:

          Group in the same domain: "%:Group Name"

          Group in any domain: "%:Group Name@FULLY.QUALIFIED.DOMAIN"

          Group SID: "%:S-1-2-34-5678901234-5678901234-5678901234-567"

     See GROUP PROVIDER PLUGINS for more information.

     Note that quotes around group names are optional.  Unquoted strings must
     use a backslash (`\') to escape spaces and special characters.  See Other
     special characters and reserved words for a list of characters that need
     to be escaped.

     Runas_List ::= Runas_Member |
                    Runas_Member ',' Runas_List

     Runas_Member ::= '!'* user name |
                      '!'* #uid |
                      '!'* %group |
                      '!'* %#gid |
                      '!'* %:nonunix_group |
                      '!'* %:#nonunix_gid |
                      '!'* +netgroup |
                      '!'* Runas_Alias

     A Runas_List is similar to a User_List except that instead of
     User_Aliases it can contain Runas_Aliases.  Note that user names and
     groups are matched as strings.  In other words, two users (groups) with
     the same uid (gid) are considered to be distinct.  If you wish to match
     all user names with the same uid (e.g. root and toor), you can use a uid
     instead (#0 in the example given).

     Host_List ::= Host |
                   Host ',' Host_List

     Host ::= '!'* host name |
              '!'* ip_addr |
              '!'* network(/netmask)? |
              '!'* +netgroup |
              '!'* Host_Alias

     A Host_List is made up of one or more host names, IP addresses, network
     numbers, netgroups (prefixed with `+') and other aliases.  Again, the
     value of an item may be negated with the `!' operator.  Host netgroups
     are matched using the host (both qualified and unqualified) and domain
     members only; the user member is not used when matching.  If you specify
     a network number without a netmask, sudo will query each of the local
     host's network interfaces and, if the network number corresponds to one
     of the hosts's network interfaces, will use the netmask of that inter-
     face.  The netmask may be specified either in standard IP address nota-
     tion (e.g. 255.255.255.0 or ffff:ffff:ffff:ffff::), or CIDR notation
     (number of bits, e.g. 24 or 64).  A host name may include shell-style
     wildcards (see the Wildcards section below), but unless the host name
     command on your machine returns the fully qualified host name, you'll
     need to use the fqdn option for wildcards to be useful.  Note that sudo
     only inspects actual network interfaces; this means that IP address
     127.0.0.1 (localhost) will never match.  Also, the host name
     ``localhost'' will only match if that is the actual host name, which is
     usually only the case for non-networked systems.

     digest ::= [A-Fa-f0-9]+ |
                [[A-Za-z0-9+/=]+

     Digest_Spec ::= "sha224" ':' digest |
                     "sha256" ':' digest |
                     "sha384" ':' digest |
                     "sha512" ':' digest

     Cmnd_List ::= Cmnd |
                   Cmnd ',' Cmnd_List

     command name ::= file name |
                      file name args |
                      file name '""'

     Cmnd ::= Digest_Spec? '!'* command name |
              '!'* directory |
              '!'* "sudoedit" |
              '!'* Cmnd_Alias

     A Cmnd_List is a list of one or more command names, directories, and
     other aliases.  A command name is a fully qualified file name which may
     include shell-style wildcards (see the Wildcards section below).  A sim-
     ple file name allows the user to run the command with any arguments
     he/she wishes.  However, you may also specify command line arguments
     (including wildcards).  Alternately, you can specify "" to indicate that
     the command may only be run without command line arguments.  A directory
     is a fully qualified path name ending in a `/'.  When you specify a
     directory in a Cmnd_List, the user will be able to run any file within
     that directory (but not in any sub-directories therein).

     If a Cmnd has associated command line arguments, then the arguments in
     the Cmnd must match exactly those given by the user on the command line
     (or match the wildcards if there are any).  Note that the following char-
     acters must be escaped with a `\' if they are used in command arguments:
     `,', `:', `=', `\'.  The built-in command ``sudoedit'' is used to permit
     a user to run sudo with the -e option (or as sudoedit).  It may take com-
     mand line arguments just as a normal command does.  Note that
     ``sudoedit'' is a command built into sudo itself and must be specified in
     the sudoers file without a leading path.

     If a command name is prefixed with a Digest_Spec, the command will only
     match successfully if it can be verified using the specified SHA-2
     digest.  The following digest formats are supported: sha224, sha256,
     sha384 and sha512.  The string may be specified in either hex or base64
     format (base64 is more compact).  There are several utilities capable of
     generating SHA-2 digests in hex format such as openssl, shasum,
     sha224sum, sha256sum, sha384sum, sha512sum.

     For example, using openssl:

     $ openssl dgst -sha224 /bin/ls
     SHA224(/bin/ls)= 118187da8364d490b4a7debbf483004e8f3e053ec954309de2c41a25

     It is also possible to use openssl to generate base64 output:

     $ openssl dgst -binary -sha224 /bin/ls | openssl base64
     EYGH2oNk1JC0p9679IMATo8+BT7JVDCd4sQaJQ==

     Warning, if the user has write access to the command itself (directly or
     via a sudo command), it may be possible for the user to replace the com-
     mand after the digest check has been performed but before the command is
     executed.  A similar race condition exists on systems that lack the
     fexecve(2) system call when the directory in which the command is located
     is writable by the user.  See the description of the fdexec setting for
     more information on how sudo executes commands that have an associated
     digest.

     Command digests are only supported by version 1.8.7 or higher.

   Defaults
     Certain configuration options may be changed from their default values at
     run-time via one or more Default_Entry lines.  These may affect all users
     on any host, all users on a specific host, a specific user, a specific
     command, or commands being run as a specific user.  Note that per-command
     entries may not include command line arguments.  If you need to specify
     arguments, define a Cmnd_Alias and reference that instead.

     Default_Type ::= 'Defaults' |
                      'Defaults' '@' Host_List |
                      'Defaults' ':' User_List |
                      'Defaults' '!' Cmnd_List |
                      'Defaults' '>' Runas_List

     Default_Entry ::= Default_Type Parameter_List

     Parameter_List ::= Parameter |
                        Parameter ',' Parameter_List

     Parameter ::= Parameter '=' Value |
                   Parameter '+=' Value |
                   Parameter '-=' Value |
                   '!'* Parameter

     Parameters may be flags, integer values, strings, or lists.  Flags are
     implicitly boolean and can be turned off via the `!' operator.  Some
     integer, string and list parameters may also be used in a boolean context
     to disable them.  Values may be enclosed in double quotes ("") when they
     contain multiple words.  Special characters may be escaped with a back-
     slash (`\').

     Lists have two additional assignment operators, += and -=.  These opera-
     tors are used to add to and delete from a list respectively.  It is not
     an error to use the -= operator to remove an element that does not exist
     in a list.

     Defaults entries are parsed in the following order: generic, host, user
     and runas Defaults first, then command defaults.  If there are multiple
     Defaults settings of the same type, the last matching setting is used.
     The following Defaults settings are parsed before all others since they
     may affect subsequent entries: fqdn, group_plugin, runas_default,
     sudoers_locale.

     See SUDOERS OPTIONS for a list of supported Defaults parameters.

   User specification
     User_Spec ::= User_List Host_List '=' Cmnd_Spec_List \
                   (':' Host_List '=' Cmnd_Spec_List)*

     Cmnd_Spec_List ::= Cmnd_Spec |
                        Cmnd_Spec ',' Cmnd_Spec_List

     Cmnd_Spec ::= Runas_Spec? Option_Spec* Tag_Spec* Cmnd

     Runas_Spec ::= '(' Runas_List? (':' Runas_List)? ')'

     Option_Spec ::= (Date_Spec | Timeout_Spec)

     Date_Spec ::= ('NOTBEFORE=timestamp' | 'NOTAFTER=timestamp')

     Timeout_Spec ::= 'TIMEOUT=timeout'

     Tag_Spec ::= ('EXEC:' | 'NOEXEC:' | 'FOLLOW:' | 'NOFOLLOW' |
                   'LOG_INPUT:' | 'NOLOG_INPUT:' | 'LOG_OUTPUT:' |
                   'NOLOG_OUTPUT:' | 'MAIL:' | 'NOMAIL:' | 'PASSWD:' |
                   'NOPASSWD:' | 'SETENV:' | 'NOSETENV:')

     A user specification determines which commands a user may run (and as
     what user) on specified hosts.  By default, commands are run as root, but
     this can be changed on a per-command basis.

     The basic structure of a user specification is ``who where = (as_whom)
     what''.  Let's break that down into its constituent parts:

   Runas_Spec
     A Runas_Spec determines the user and/or the group that a command may be
     run as.  A fully-specified Runas_Spec consists of two Runas_Lists (as
     defined above) separated by a colon (`:') and enclosed in a set of paren-
     theses.  The first Runas_List indicates which users the command may be
     run as via sudo's -u option.  The second defines a list of groups that
     can be specified via sudo's -g option.  If both Runas_Lists are speci-
     fied, the command may be run with any combination of users and groups
     listed in their respective Runas_Lists. If only the first is specified,
     the command may be run as any user in the list but no -g option may be
     specified.  If the first Runas_List is empty but the second is specified,
     the command may be run as the invoking user with the group set to any
     listed in the Runas_List.  If both Runas_Lists are empty, the command may
     only be run as the invoking user.  If no Runas_Spec is specified the com-
     mand may be run as root and no group may be specified.

     A Runas_Spec sets the default for the commands that follow it.  What this
     means is that for the entry:

     dgb     boulder = (operator) /bin/ls, /bin/kill, /usr/bin/lprm

     The user dgb may run /bin/ls, /bin/kill, and /usr/bin/lprm--but only as
     operator.  E.g.,

     $ sudo -u operator /bin/ls

     It is also possible to override a Runas_Spec later on in an entry.  If we
     modify the entry like so:

     dgb     boulder = (operator) /bin/ls, (root) /bin/kill, /usr/bin/lprm

     Then user dgb is now allowed to run /bin/ls as operator, but /bin/kill
     and /usr/bin/lprm as root.

     We can extend this to allow dgb to run /bin/ls with either the user or
     group set to operator:

     dgb     boulder = (operator : operator) /bin/ls, (root) /bin/kill,\
             /usr/bin/lprm

     Note that while the group portion of the Runas_Spec permits the user to
     run as command with that group, it does not force the user to do so.  If
     no group is specified on the command line, the command will run with the
     group listed in the target user's password database entry.  The following
     would all be permitted by the sudoers entry above:

     $ sudo -u operator /bin/ls
     $ sudo -u operator -g operator /bin/ls
     $ sudo -g operator /bin/ls

     In the following example, user tcm may run commands that access a modem
     device file with the dialer group.

     tcm     boulder = (:dialer) /usr/bin/tip, /usr/bin/cu,\
             /usr/local/bin/minicom

     Note that in this example only the group will be set, the command still
     runs as user tcm.  E.g.

     $ sudo -g dialer /usr/bin/cu

     Multiple users and groups may be present in a Runas_Spec, in which case
     the user may select any combination of users and groups via the -u and -g
     options.  In this example:

     alan    ALL = (root, bin : operator, system) ALL

     user alan may run any command as either user root or bin, optionally set-
     ting the group to operator or system.

   Option_Spec
     A Cmnd may have zero or more options associated with it.  Depending on
     the system, options may consist of SELinux roles and/or types, Solaris
     privileges sets, and command timeouts.  Once an option is set for a Cmnd,
     subsequent Cmnds in the Cmnd_Spec_List, inherit that option unless it is
     overridden by another option.

   Date_Spec
     sudoers rules can be specified with a start and end date via the
     NOTBEFORE and NOTAFTER settings.  The time stamp must be specified in
     Generalized Time as defined by RFC 4517.  The format is effectively
     yyyymmddHHMMSSZ where the minutes and seconds are optional.  The `Z' suf-
     fix indicates that the time stamp is in Coordinated Universal Time (UTC).
     It is also possible to specify a timezone offset from UTC in hours and
     minutes instead of a `Z'.  For example, `-0500' would correspond to East-
     ern Standard time in the US.  As an extension, if no `Z' or timezone off-
     set is specified, local time will be used.

     The following are all valid time stamps:

         20170214083000Z
         2017021408Z
         20160315220000-0500
         20151201235900

   Timeout_Spec
     A command may have a timeout associated with it.  If the timeout expires
     before the command has exited, the command will be terminated.  The time-
     out may be specified in combinations of days, hours, minutes and seconds
     with a single-letter case-insensitive suffix that indicates the unit of
     time.  For example, a timeout of 7 days, 8 hours, 30 minutes and 10 sec-
     onds would be written as 7d8h30m10s.  If a number is specified without a
     unit, seconds are assumed.  Any of the days, minutes, hours or seconds
     may be omitted.  The order must be from largest to smallest unit and a
     unit may not be specified more than once.

     The following are all valid timeout values: 7d8h30m10s, 14d, 8h30m, 600s,
     3600.  The following are invalid timeout values: 12m2w1d, 30s10m4h,
     1d2d3h.

     This option is only supported by version 1.8.20 or higher.

   Tag_Spec
     A command may have zero or more tags associated with it.  The following
     tag values are supported: EXEC, NOEXEC, FOLLOW, NOFOLLOW, LOG_INPUT,
     NOLOG_INPUT, LOG_OUTPUT, NOLOG_OUTPUT, MAIL, NOMAIL, PASSWD, NOPASSWD,
     SETENV, and NOSETENV.  Once a tag is set on a Cmnd, subsequent Cmnds in
     the Cmnd_Spec_List, inherit the tag unless it is overridden by the oppo-
     site tag (in other words, PASSWD overrides NOPASSWD and NOEXEC overrides
     EXEC).

     EXEC and NOEXEC

       If sudo has been compiled with noexec support and the underlying oper-
       ating system supports it, the NOEXEC tag can be used to prevent a
       dynamically-linked executable from running further commands itself.

       In the following example, user aaron may run /usr/bin/more and
       /usr/bin/vi but shell escapes will be disabled.

       aaron   shanty = NOEXEC: /usr/bin/more, /usr/bin/vi

       See the Preventing shell escapes section below for more details on how
       NOEXEC works and whether or not it will work on your system.

     FOLLOW and NOFOLLOW Starting with version 1.8.15, sudoedit will not open
       a file that is a symbolic link unless the sudoedit_follow option is
       enabled.  The FOLLOW and NOFOLLOW tags override the value of
       sudoedit_follow and can be used to permit (or deny) the editing of sym-
       bolic links on a per-command basis.  These tags are only effective for
       the sudoedit command and are ignored for all other commands.

     LOG_INPUT and NOLOG_INPUT

       These tags override the value of the log_input option on a per-command
       basis.  For more information, see the description of log_input in the
       SUDOERS OPTIONS section below.

     LOG_OUTPUT and NOLOG_OUTPUT

       These tags override the value of the log_output option on a per-command
       basis.  For more information, see the description of log_output in the
       SUDOERS OPTIONS section below.

     MAIL and NOMAIL

       These tags provide fine-grained control over whether mail will be sent
       when a user runs a command by overriding the value of the
       mail_all_cmnds option on a per-command basis.  They have no effect when
       sudo is run with the -l or -v options.  A NOMAIL tag will also override
       the mail_always and mail_no_perms options.  For more information, see
       the descriptions of mail_all_cmnds, mail_always, and mail_no_perms in
       the SUDOERS OPTIONS section below.

     PASSWD and NOPASSWD

       By default, sudo requires that a user authenticate him or herself
       before running a command.  This behavior can be modified via the
       NOPASSWD tag.  Like a Runas_Spec, the NOPASSWD tag sets a default for
       the commands that follow it in the Cmnd_Spec_List.  Conversely, the
       PASSWD tag can be used to reverse things.  For example:

       ray     rushmore = NOPASSWD: /bin/kill, /bin/ls, /usr/bin/lprm

       would allow the user ray to run /bin/kill, /bin/ls, and /usr/bin/lprm
       as root on the machine rushmore without authenticating himself.  If we
       only want ray to be able to run /bin/kill without a password the entry
       would be:

       ray     rushmore = NOPASSWD: /bin/kill, PASSWD: /bin/ls, /usr/bin/lprm

       Note, however, that the PASSWD tag has no effect on users who are in
       the group specified by the exempt_group option.

       By default, if the NOPASSWD tag is applied to any of the entries for a
       user on the current host, he or she will be able to run ``sudo -l''
       without a password.  Additionally, a user may only run ``sudo -v''
       without a password if the NOPASSWD tag is present for all a user's
       entries that pertain to the current host.  This behavior may be over-
       ridden via the verifypw and listpw options.

     SETENV and NOSETENV

       These tags override the value of the setenv option on a per-command
       basis.  Note that if SETENV has been set for a command, the user may
       disable the env_reset option from the command line via the -E option.
       Additionally, environment variables set on the command line are not
       subject to the restrictions imposed by env_check, env_delete, or
       env_keep.  As such, only trusted users should be allowed to set vari-
       ables in this manner.  If the command matched is ALL, the SETENV tag is
       implied for that command; this default may be overridden by use of the
       NOSETENV tag.

   Wildcards
     sudo allows shell-style wildcards (aka meta or glob characters) to be
     used in host names, path names and command line arguments in the sudoers
     file.  Wildcard matching is done via the glob(3) and fnmatch(3) functions
     as specified by IEEE Std 1003.1 (``POSIX.1'').

     *         Matches any set of zero or more characters (including white
               space).

     ?         Matches any single character (including white space).

     [...]     Matches any character in the specified range.

     [!...]    Matches any character not in the specified range.

     \x        For any character `x', evaluates to `x'.  This is used to
               escape special characters such as: `*', `?', `[', and `]'.

     Note that these are not regular expressions.  Unlike a regular expression
     there is no way to match one or more characters within a range.

     Character classes may be used if your system's glob(3) and fnmatch(3)
     functions support them.  However, because the `:' character has special
     meaning in sudoers, it must be escaped.  For example:

         /bin/ls [[\:alpha\:]]*

     Would match any file name beginning with a letter.

     Note that a forward slash (`/') will not be matched by wildcards used in
     the file name portion of the command.  This is to make a path like:

         /usr/bin/*

     match /usr/bin/who but not /usr/bin/X11/xterm.

     When matching the command line arguments, however, a slash does get
     matched by wildcards since command line arguments may contain arbitrary
     strings and not just path names.

     Wildcards in command line arguments should be used with care.
     Command line arguments are matched as a single, concatenated string.
     This mean a wildcard character such as `?' or `*' will match across word
     boundaries, which may be unexpected.  For example, while a sudoers entry
     like:

         %operator ALL = /bin/cat /var/log/messages*

     will allow command like:

         $ sudo cat /var/log/messages.1

     It will also allow:

         $ sudo cat /var/log/messages /etc/shadow

     which is probably not what was intended.  In most cases it is better to
     do command line processing outside of the sudoers file in a scripting
     language.

   Exceptions to wildcard rules
     The following exceptions apply to the above rules:

     ""        If the empty string "" is the only command line argument in the
               sudoers file entry it means that command is not allowed to be
               run with any arguments.

     sudoedit  Command line arguments to the sudoedit built-in command should
               always be path names, so a forward slash (`/') will not be
               matched by a wildcard.

   Including other files from within sudoers
     It is possible to include other sudoers files from within the sudoers
     file currently being parsed using the #include and #includedir direc-
     tives.

     This can be used, for example, to keep a site-wide sudoers file in addi-
     tion to a local, per-machine file.  For the sake of this example the
     site-wide sudoers file will be /etc/sudoers and the per-machine one will
     be /etc/sudoers.local.  To include /etc/sudoers.local from within
     /etc/sudoers we would use the following line in /etc/sudoers:

         #include /etc/sudoers.local

     When sudo reaches this line it will suspend processing of the current
     file (/etc/sudoers) and switch to /etc/sudoers.local.  Upon reaching the
     end of /etc/sudoers.local, the rest of /etc/sudoers will be processed.
     Files that are included may themselves include other files.  A hard limit
     of 128 nested include files is enforced to prevent include file loops.

     If the path to the include file is not fully-qualified (does not begin
     with a `/', it must be located in the same directory as the sudoers file
     it was included from.  For example, if /etc/sudoers contains the line:

         #include sudoers.local

     the file that will be included is /etc/sudoers.local.

     The file name may also include the %h escape, signifying the short form
     of the host name.  In other words, if the machine's host name is
     ``xerxes'', then

         #include /etc/sudoers.%h

     will cause sudo to include the file /etc/sudoers.xerxes.

     The #includedir directive can be used to create a sudoers.d directory
     that the system package manager can drop sudoers file rules into as part
     of package installation.  For example, given:

         #includedir /etc/sudoers.d

     sudo will suspend processing of the current file and read each file in
     /etc/sudoers.d, skipping file names that end in `~' or contain a `.'
     character to avoid causing problems with package manager or editor tempo-
     rary/backup files.  Files are parsed in sorted lexical order.  That is,
     /etc/sudoers.d/01_first will be parsed before /etc/sudoers.d/10_second.
     Be aware that because the sorting is lexical, not numeric,
     /etc/sudoers.d/1_whoops would be loaded after /etc/sudoers.d/10_second.
     Using a consistent number of leading zeroes in the file names can be used
     to avoid such problems.  After parsing the files in the directory, con-
     trol returns to the file that contained the #includedir directive.

     Note that unlike files included via #include, visudo will not edit the
     files in a #includedir directory unless one of them contains a syntax
     error.  It is still possible to run visudo with the -f flag to edit the
     files directly, but this will not catch the redefinition of an alias that
     is also present in a different file.

   Other special characters and reserved words
     The pound sign (`#') is used to indicate a comment (unless it is part of
     a #include directive or unless it occurs in the context of a user name
     and is followed by one or more digits, in which case it is treated as a
     uid).  Both the comment character and any text after it, up to the end of
     the line, are ignored.

     The reserved word ALL is a built-in alias that always causes a match to
     succeed.  It can be used wherever one might otherwise use a Cmnd_Alias,
     User_Alias, Runas_Alias, or Host_Alias.  You should not try to define
     your own alias called ALL as the built-in alias will be used in prefer-
     ence to your own.  Please note that using ALL can be dangerous since in a
     command context, it allows the user to run any command on the system.

     An exclamation point (`!') can be used as a logical not operator in a
     list or alias as well as in front of a Cmnd.  This allows one to exclude
     certain values.  For the `!' operator to be effective, there must be
     something for it to exclude.  For example, to match all users except for
     root one would use:

         ALL,!root

     If the ALL, is omitted, as in:

         !root

     it would explicitly deny root but not match any other users.  This is
     different from a true ``negation'' operator.

     Note, however, that using a `!' in conjunction with the built-in ALL
     alias to allow a user to run ``all but a few'' commands rarely works as
     intended (see SECURITY NOTES below).

     Long lines can be continued with a backslash (`\') as the last character
     on the line.

     White space between elements in a list as well as special syntactic char-
     acters in a User Specification (`=', `:', `(', `)') is optional.

     The following characters must be escaped with a backslash (`\') when used
     as part of a word (e.g. a user name or host name): `!', `=', `:', `,',
     `(', `)', `\'.

SUDOERS OPTIONS
     sudo's behavior can be modified by Default_Entry lines, as explained ear-
     lier.  A list of all supported Defaults parameters, grouped by type, are
     listed below.

     Boolean Flags:

     always_query_group_plugin
                       If a group_plugin is configured, use it to resolve
                       groups of the form %group as long as there is not also
                       a system group of the same name.  Normally, only groups
                       of the form %:group are passed to the group_plugin.
                       This flag is off by default.

     always_set_home   If enabled, sudo will set the HOME environment variable
                       to the home directory of the target user (which is root
                       unless the -u option is used).  This effectively means
                       that the -H option is always implied.  Note that by
                       default, HOME will be set to the home directory of the
                       target user when the env_reset option is enabled, so
                       always_set_home only has an effect for configurations
                       where either env_reset is disabled or HOME is present
                       in the env_keep list.  This flag is off by default.

     authenticate      If set, users must authenticate themselves via a pass-
                       word (or other means of authentication) before they may
                       run commands.  This default may be overridden via the
                       PASSWD and NOPASSWD tags.  This flag is on by default.

     closefrom_override
                       If set, the user may use sudo's -C option which over-
                       rides the default starting point at which sudo begins
                       closing open file descriptors.  This flag is off by
                       default.

     compress_io       If set, and sudo is configured to log a command's input
                       or output, the I/O logs will be compressed using zlib.
                       This flag is on by default when sudo is compiled with
                       zlib support.

     exec_background   By default, sudo runs a command as the foreground
                       process as long as sudo itself is running in the fore-
                       ground.  When the exec_background flag is enabled and
                       the command is being run in a pty (due to I/O logging
                       or the use_pty flag), the command will be run as a
                       background process.  Attempts to read from the control-
                       ling terminal (or to change terminal settings) will
                       result in the command being suspended with the SIGTTIN
                       signal (or SIGTTOU in the case of terminal settings).
                       If this happens when sudo is a foreground process, the
                       command will be granted the controlling terminal and
                       resumed in the foreground with no user intervention
                       required.  The advantage of initially running the com-
                       mand in the background is that sudo need not read from
                       the terminal unless the command explicitly requests it.
                       Otherwise, any terminal input must be passed to the
                       command, whether it has required it or not (the kernel
                       buffers terminals so it is not possible to tell whether
                       the command really wants the input).  This is different
                       from historic sudo behavior or when the command is not
                       being run in a pty.

                       For this to work seamlessly, the operating system must
                       support the automatic restarting of system calls.
                       Unfortunately, not all operating systems do this by
                       default, and even those that do may have bugs.  For
                       example, Mac OS X fails to restart the tcgetattr() and
                       tcsetattr() system calls (this is a bug in Mac OS X).
                       Furthermore, because this behavior depends on the com-
                       mand stopping with the SIGTTIN or SIGTTOU signals, pro-
                       grams that catch these signals and suspend themselves
                       with a different signal (usually SIGTOP) will not be
                       automatically foregrounded.  Some versions of the linux
                       su(1) command behave this way.  This flag is off by
                       default.

                       This setting is only supported by version 1.8.7 or
                       higher.  It has no effect unless I/O logging is enabled
                       or the use_pty flag is enabled.

     env_editor        If set, visudo will use the value of the EDITOR or
                       VISUAL environment variables before falling back on the
                       default editor list.  Note that this may create a secu-
                       rity hole as it allows the user to run any arbitrary
                       command as root without logging.  A safer alternative
                       is to place a colon-separated list of editors in the
                       editor variable.  visudo will then only use the EDITOR
                       or VISUAL if they match a value specified in editor.
                       If the env_reset flag is enabled, the EDITOR and/or
                       VISUAL environment variables must be present in the
                       env_keep list for the env_editor flag to function when
                       visudo is invoked via sudo.  This flag is on by
                       default.

     env_reset         If set, sudo will run the command in a minimal environ-
                       ment containing the TERM, PATH, HOME, MAIL, SHELL,
                       LOGNAME, USER, USERNAME and SUDO_* variables.  Any
                       variables in the caller's environment or in the file
                       specified by the restricted_env_file option that match
                       the env_keep and env_check lists are then added, fol-
                       lowed by any variables present in the file specified by
                       the env_file option (if any).  The contents of the
                       env_keep and env_check lists, as modified by global
                       Defaults parameters in sudoers, are displayed when sudo
                       is run by root with the -V option.  If the secure_path
                       option is set, its value will be used for the PATH
                       environment variable.  This flag is on by default.

     fast_glob         Normally, sudo uses the glob(3) function to do shell-
                       style globbing when matching path names.  However,
                       since it accesses the file system, glob(3) can take a
                       long time to complete for some patterns, especially
                       when the pattern references a network file system that
                       is mounted on demand (auto mounted).  The fast_glob
                       option causes sudo to use the fnmatch(3) function,
                       which does not access the file system to do its match-
                       ing.  The disadvantage of fast_glob is that it is
                       unable to match relative path names such as ./ls or
                       ../bin/ls.  This has security implications when path
                       names that include globbing characters are used with
                       the negation operator, `!', as such rules can be triv-
                       ially bypassed.  As such, this option should not be
                       used when the sudoers file contains rules that contain
                       negated path names which include globbing characters.
                       This flag is off by default.

     fqdn              Set this flag if you want to put fully qualified host
                       names in the sudoers file when the local host name (as
                       returned by the hostname command) does not contain the
                       domain name.  In other words, instead of myhost you
                       would use myhost.mydomain.edu.  You may still use the
                       short form if you wish (and even mix the two).  This
                       option is only effective when the ``canonical'' host
                       name, as returned by the getaddrinfo() or
                       gethostbyname() function, is a fully-qualified domain
                       name.  This is usually the case when the system is con-
                       figured to use DNS for host name resolution.

                       If the system is configured to use the /etc/hosts file
                       in preference to DNS, the ``canonical'' host name may
                       not be fully-qualified.  The order that sources are
                       queried for host name resolution is usually specified
                       in the /etc/nsswitch.conf, /etc/netsvc.conf,
                       /etc/host.conf, or, in some cases, /etc/resolv.conf
                       file.  In the /etc/hosts file, the first host name of
                       the entry is considered to be the ``canonical'' name;
                       subsequent names are aliases that are not used by
                       sudoers.  For example, the following hosts file line
                       for the machine ``xyzzy'' has the fully-qualified
                       domain name as the ``canonical'' host name, and the
                       short version as an alias.

                             192.168.1.1    xyzzy.sudo.ws xyzzy

                       If the machine's hosts file entry is not formatted
                       properly, the fqdn option will not be effective if it
                       is queried before DNS.

                       Beware that when using DNS for host name resolution,
                       turning on fqdn requires sudoers to make DNS lookups
                       which renders sudo unusable if DNS stops working (for
                       example if the machine is disconnected from the net-
                       work).  Also note that just like with the hosts file,
                       you must use the ``canonical'' name as DNS knows it.
                       That is, you may not use a host alias (CNAME entry) due
                       to performance issues and the fact that there is no way
                       to get all aliases from DNS.

                       This flag is off by default.

     ignore_audit_errors
                       Allow commands to be run even if sudoers cannot write
                       to the audit log.  If enabled, an audit log write fail-
                       ure is not treated as a fatal error.  If disabled, a
                       command may only be run after the audit event is suc-
                       cessfully written.  This flag is only effective on sys-
                       tems for which sudoers supports audit logging, includ-
                       ing FreeBSD, Linux, Mac OS X and Solaris.  This flag is
                       on by default.

     ignore_dot        If set, sudo will ignore "." or "" (both denoting cur-
                       rent directory) in the PATH environment variable; the
                       PATH itself is not modified.  This flag is on by
                       default.

     ignore_iolog_errors
                       Allow commands to be run even if sudoers cannot write
                       to the I/O log.  If enabled, an I/O log write failure
                       is not treated as a fatal error.  If disabled, the com-
                       mand will be terminated if the I/O log cannot be writ-
                       ten to.  This flag is off by default.

     ignore_logfile_errors
                       Allow commands to be run even if sudoers cannot write
                       to the log file.  If enabled, a log file write failure
                       is not treated as a fatal error.  If disabled, a com-
                       mand may only be run after the log file entry is suc-
                       cessfully written.  This flag only has an effect when
                       sudoers is configured to use file-based logging via the
                       logfile option.  This flag is on by default.

     ignore_local_sudoers
                       If set via LDAP, parsing of /etc/sudoers will be
                       skipped.  This is intended for Enterprises that wish to
                       prevent the usage of local sudoers files so that only
                       LDAP is used.  This thwarts the efforts of rogue opera-
                       tors who would attempt to add roles to /etc/sudoers.
                       When this option is present, /etc/sudoers does not even
                       need to exist.  Since this option tells sudo how to
                       behave when no specific LDAP entries have been matched,
                       this sudoOption is only meaningful for the cn=defaults
                       section.  This flag is off by default.

     ignore_unknown_defaults
                       If set, sudo will not produce a warning if it encoun-
                       ters an unknown Defaults entry in the sudoers file or
                       an unknown sudoOption in LDAP.  This flag is off by
                       default.

     insults           If set, sudo will insult users when they enter an
                       incorrect password.  This flag is off by default.

     log_host          If set, the host name will be logged in the (non-sys-
                       log) sudo log file.  This flag is off by default.

     log_input         If set, sudo will run the command in a pseudo-tty and
                       log all user input.  If the standard input is not con-
                       nected to the user's tty, due to I/O redirection or
                       because the command is part of a pipeline, that input
                       is also captured and stored in a separate log file.
                       For more information, see the I/O LOG FILES section.
                       This flag is off by default.

     log_output        If set, sudo will run the command in a pseudo-tty and
                       log all output that is sent to the screen, similar to
                       the script(1) command.  For more information, see the
                       I/O LOG FILES section.  This flag is off by default.

     log_year          If set, the four-digit year will be logged in the (non-
                       syslog) sudo log file.  This flag is off by default.

     long_otp_prompt   When validating with a One Time Password (OTP) scheme
                       such as S/Key or OPIE, a two-line prompt is used to
                       make it easier to cut and paste the challenge to a
                       local window.  It's not as pretty as the default but
                       some people find it more convenient.  This flag is off
                       by default.

     mail_all_cmnds    Send mail to the mailto user every time a user attempts
                       to run a command via sudo (this includes sudoedit).  No
                       mail will be sent if the user runs sudo with the -l or
                       -v option unless there is an authentication error and
                       the mail_badpass flag is also set.  This flag is off by
                       default.

     mail_always       Send mail to the mailto user every time a user runs
                       sudo.  This flag is off by default.

     mail_badpass      Send mail to the mailto user if the user running sudo
                       does not enter the correct password.  If the command
                       the user is attempting to run is not permitted by
                       sudoers and one of the mail_all_cmnds, mail_always,
                       mail_no_host, mail_no_perms or mail_no_user flags are
                       set, this flag will have no effect.  This flag is off
                       by default.

     mail_no_host      If set, mail will be sent to the mailto user if the
                       invoking user exists in the sudoers file, but is not
                       allowed to run commands on the current host.  This flag
                       is off by default.

     mail_no_perms     If set, mail will be sent to the mailto user if the
                       invoking user is allowed to use sudo but the command
                       they are trying is not listed in their sudoers file
                       entry or is explicitly denied.  This flag is off by
                       default.

     mail_no_user      If set, mail will be sent to the mailto user if the
                       invoking user is not in the sudoers file.  This flag is
                       on by default.

     match_group_by_gid
                       By default, sudoers will look up each group the user is
                       a member of by group ID to determine the group name
                       (this is only done once).  The resulting list of the
                       user's group names is used when matching groups listed
                       in the sudoers file.  This works well on systems where
                       the number of groups listed in the sudoers file is
                       larger than the number of groups a typical user belongs
                       to.  On systems where group lookups are slow, where
                       users may belong to a large number of groups, and where
                       the number of groups listed in the sudoers file is rel-
                       atively small, it may be prohibitively expensive and
                       running commands via sudo may take longer than normal.
                       On such systems it may be faster to use the
                       match_group_by_gid flag to avoid resolving the user's
                       group IDs to group names.  In this case, sudoers must
                       look up any group name listed in the sudoers file and
                       use the group ID instead of the group name when deter-
                       mining whether the user is a member of the group.

                       Note that if match_group_by_gid is enabled, group data-
                       base lookups performed by sudoers will be keyed by
                       group name as opposed to group ID.  On systems where
                       there are multiple sources for the group database, it
                       is possible to have conflicting group names or group
                       IDs in the local /etc/group file and the remote group
                       database.  On such systems, enabling or disabling
                       match_group_by_gid can be used to choose whether group
                       database queries are performed by name (enabled) or ID
                       (disabled), which may aid in working around group entry
                       conflicts.

                       The match_group_by_gid flag has no effect when sudoers
                       data is stored in LDAP.  This flag is off by default.

                       This setting is only supported by version 1.8.18 or
                       higher.

     netgroup_tuple    If set, netgroup lookups will be performed using the
                       full netgroup tuple: host name, user name and domain
                       (if one is set).  Historically, sudo only matched the
                       user name and domain for netgroups used in a User_List
                       and only matched the host name and domain for netgroups
                       used in a Host_List.  This flag is off by default.

     noexec            If set, all commands run via sudo will behave as if the
                       NOEXEC tag has been set, unless overridden by an EXEC
                       tag.  See the description of EXEC and NOEXEC above as
                       well as the Preventing shell escapes section at the end
                       of this manual.  This flag is off by default.

     pam_session       On systems that use PAM for authentication, sudo will
                       create a new PAM session for the command to be run in.
                       Disabling pam_session may be needed on older PAM imple-
                       mentations or on operating systems where opening a PAM
                       session changes the utmp or wtmp files.  If PAM session
                       support is disabled, resource limits may not be updated
                       for the command being run.  If pam_session,
                       pam_setcred, and use_pty are disabled and I/O logging
                       has not been configured, sudo will execute the command
                       directly instead of running it as a child process.
                       This flag is on by default.

                       This setting is only supported by version 1.8.7 or
                       higher.

     pam_setcred       On systems that use PAM for authentication, sudo will
                       attempt to establish credentials for the target user by
                       default, if supported by the underlying authentication
                       system.  One example of a credential is a Kerberos
                       ticket.  If pam_session, pam_setcred, and use_pty are
                       disabled and I/O logging has not been configured, sudo
                       will execute the command directly instead of running it
                       as a child process.  This flag is on by default.

                       This setting is only supported by version 1.8.8 or
                       higher.

     passprompt_override
                       The password prompt specified by passprompt will nor-
                       mally only be used if the password prompt provided by
                       systems such as PAM matches the string ``Password:''.
                       If passprompt_override is set, passprompt will always
                       be used.  This flag is off by default.

     path_info         Normally, sudo will tell the user when a command could
                       not be found in their PATH environment variable.  Some
                       sites may wish to disable this as it could be used to
                       gather information on the location of executables that
                       the normal user does not have access to.  The disadvan-
                       tage is that if the executable is simply not in the
                       user's PATH, sudo will tell the user that they are not
                       allowed to run it, which can be confusing.  This flag
                       is off by default.

     preserve_groups   By default, sudo will initialize the group vector to
                       the list of groups the target user is in.  When
                       preserve_groups is set, the user's existing group vec-
                       tor is left unaltered.  The real and effective group
                       IDs, however, are still set to match the target user.
                       This flag is off by default.

     pwfeedback        By default, sudo reads the password like most other
                       Unix programs, by turning off echo until the user hits
                       the return (or enter) key.  Some users become confused
                       by this as it appears to them that sudo has hung at
                       this point.  When pwfeedback is set, sudo will provide
                       visual feedback when the user presses a key.  Note that
                       this does have a security impact as an onlooker may be
                       able to determine the length of the password being
                       entered.  This flag is off by default.

     requiretty        If set, sudo will only run when the user is logged in
                       to a real tty.  When this flag is set, sudo can only be
                       run from a login session and not via other means such
                       as cron(8) or cgi-bin scripts.  This flag is off by
                       default.

     root_sudo         If set, root is allowed to run sudo too.  Disabling
                       this prevents users from ``chaining'' sudo commands to
                       get a root shell by doing something like ``sudo sudo
                       /bin/sh''.  Note, however, that turning off root_sudo
                       will also prevent root from running sudoedit.  Dis-
                       abling root_sudo provides no real additional security;
                       it exists purely for historical reasons.  This flag is
                       on by default.

     rootpw            If set, sudo will prompt for the root password instead
                       of the password of the invoking user when running a
                       command or editing a file.  This flag is off by
                       default.

     runaspw           If set, sudo will prompt for the password of the user
                       defined by the runas_default option (defaults to root)
                       instead of the password of the invoking user when run-
                       ning a command or editing a file.  This flag is off by
                       default.

     set_home          If enabled and sudo is invoked with the -s option the
                       HOME environment variable will be set to the home
                       directory of the target user (which is root unless the
                       -u option is used).  This effectively makes the -s
                       option imply -H.  Note that HOME is already set when
                       the env_reset option is enabled, so set_home is only
                       effective for configurations where either env_reset is
                       disabled or HOME is present in the env_keep list.  This
                       flag is off by default.

     set_logname       Normally, sudo will set the LOGNAME, USER and USERNAME
                       environment variables to the name of the target user
                       (usually root unless the -u option is given).  However,
                       since some programs (including the RCS revision control
                       system) use LOGNAME to determine the real identity of
                       the user, it may be desirable to change this behavior.
                       This can be done by negating the set_logname option.
                       Note that set_logname will have no effect if the
                       env_reset option has not been disabled and the env_keep
                       list contains LOGNAME, USER or USERNAME.  This flag is
                       on by default.

     set_utmp          When enabled, sudo will create an entry in the utmp (or
                       utmpx) file when a pseudo-tty is allocated.  A pseudo-
                       tty is allocated by sudo when the log_input, log_output
                       or use_pty flags are enabled.  By default, the new
                       entry will be a copy of the user's existing utmp entry
                       (if any), with the tty, time, type and pid fields
                       updated.  This flag is on by default.

     setenv            Allow the user to disable the env_reset option from the
                       command line via the -E option.  Additionally, environ-
                       ment variables set via the command line are not subject
                       to the restrictions imposed by env_check, env_delete,
                       or env_keep.  As such, only trusted users should be
                       allowed to set variables in this manner.  This flag is
                       off by default.

     shell_noargs      If set and sudo is invoked with no arguments it acts as
                       if the -s option had been given.  That is, it runs a
                       shell as root (the shell is determined by the SHELL
                       environment variable if it is set, falling back on the
                       shell listed in the invoking user's /etc/passwd entry
                       if not).  This flag is off by default.

     stay_setuid       Normally, when sudo executes a command the real and
                       effective UIDs are set to the target user (root by
                       default).  This option changes that behavior such that
                       the real UID is left as the invoking user's UID.  In
                       other words, this makes sudo act as a setuid wrapper.
                       This can be useful on systems that disable some poten-
                       tially dangerous functionality when a program is run
                       setuid.  This option is only effective on systems that
                       support either the setreuid(2) or setresuid(2) system
                       call.  This flag is off by default.

     sudoedit_checkdir
                       If set, sudoedit will check all directory components of
                       the path to be edited for writability by the invoking
                       user.  Symbolic links will not be followed in writable
                       directories and sudoedit will refuse to edit a file
                       located in a writable directory.  These restrictions
                       are not enforced when sudoedit is run by root.  On some
                       systems, if all directory components of the path to be
                       edited are not readable by the target user, sudoedit
                       will be unable to edit the file.  This flag is on by
                       default.

                       This setting was first introduced in version 1.8.15 but
                       initially suffered from a race condition.  The check
                       for symbolic links in writable intermediate directories
                       was added in version 1.8.16.

     sudoedit_follow   By default, sudoedit will not follow symbolic links
                       when opening files.  The sudoedit_follow option can be
                       enabled to allow sudoedit to open symbolic links.  It
                       may be overridden on a per-command basis by the FOLLOW
                       and NOFOLLOW tags.  This flag is off by default.

                       This setting is only supported by version 1.8.15 or
                       higher.

     targetpw          If set, sudo will prompt for the password of the user
                       specified by the -u option (defaults to root) instead
                       of the password of the invoking user when running a
                       command or editing a file.  Note that this flag pre-
                       cludes the use of a uid not listed in the passwd data-
                       base as an argument to the -u option.  This flag is off
                       by default.

     tty_tickets       If set, users must authenticate on a per-tty basis.
                       With this flag enabled, sudo will use a separate record
                       in the time stamp file for each tty.  If disabled, a
                       single record is used for all login sessions.  This
                       flag is on by default.

     umask_override    If set, sudo will set the umask as specified in the
                       sudoers file without modification.  This makes it pos-
                       sible to specify a umask in the sudoers file that is
                       more permissive than the user's own umask and matches
                       historical behavior.  If umask_override is not set,
                       sudo will set the umask to be the union of the user's
                       umask and what is specified in sudoers.  This flag is
                       off by default.

     use_loginclass    If set, sudo will apply the defaults specified for the
                       target user's login class if one exists.  Only avail-
                       able if sudo is configured with the --with-logincap
                       option.  This flag is off by default.

     use_netgroups     If set, netgroups (prefixed with `+'), may be used in
                       place of a user or host.  For LDAP-based sudoers, net-
                       group support requires an expensive substring match on
                       the server unless the NETGROUP_BASE directive is
                       present in the /etc/ldap.conf file.  If netgroups are
                       not needed, this option can be disabled to reduce the
                       load on the LDAP server.  This flag is on by default.

     use_pty           If set, sudo will run the command in a pseudo-pty even
                       if no I/O logging is being gone.  A malicious program
                       run under sudo could conceivably fork a background
                       process that retains to the user's terminal device
                       after the main program has finished executing.  Use of
                       this option will make that impossible.  This flag is
                       off by default.

     user_command_timeouts
                       If set, the user may specify a timeout on the command
                       line.  If the timeout expires before the command has
                       exited, the command will be terminated.  If a timeout
                       is specified both in the sudoers file and on the com-
                       mand line, the smaller of the two timeouts will be
                       used.  See the Timeout_Spec section for a description
                       of the timeout syntax.  This flag is off by default.

                       This setting is only supported by version 1.8.20 or
                       higher.

     utmp_runas        If set, sudo will store the name of the runas user when
                       updating the utmp (or utmpx) file.  By default, sudo
                       stores the name of the invoking user.  This flag is off
                       by default.

     visiblepw         By default, sudo will refuse to run if the user must
                       enter a password but it is not possible to disable echo
                       on the terminal.  If the visiblepw flag is set, sudo
                       will prompt for a password even when it would be visi-
                       ble on the screen.  This makes it possible to run
                       things like ``ssh somehost sudo ls'' since by default,
                       ssh(1) does not allocate a tty when running a command.
                       This flag is off by default.

     Integers:

     closefrom         Before it executes a command, sudo will close all open
                       file descriptors other than standard input, standard
                       output and standard error (ie: file descriptors 0-2).
                       The closefrom option can be used to specify a different
                       file descriptor at which to start closing.  The default
                       is 3.

     command_timeout   The maximum amount of time a command is allowed to run
                       before it is terminated.  See the Timeout_Spec section
                       for a description of the timeout syntax.

                       This setting is only supported by version 1.8.20 or
                       higher.

     maxseq            The maximum sequence number that will be substituted
                       for the ``%{seq}'' escape in the I/O log file (see the
                       iolog_dir description above for more information).
                       While the value substituted for ``%{seq}'' is in base
                       36, maxseq itself should be expressed in decimal.  Val-
                       ues larger than 2176782336 (which corresponds to the
                       base 36 sequence number ``ZZZZZZ'') will be silently
                       truncated to 2176782336.  The default value is
                       2176782336.

                       Once the local sequence number reaches the value of
                       maxseq, it will ``roll over'' to zero, after which
                       sudoers will truncate and re-use any existing I/O log
                       path names.

                       This setting is only supported by version 1.8.7 or
                       higher.

     passwd_tries      The number of tries a user gets to enter his/her pass-
                       word before sudo logs the failure and exits.  The
                       default is 3.

     syslog_maxlen     On many systems, syslog(3) has a relatively small log
                       buffer.  IETF RFC 5424 states that syslog servers must
                       support messages of at least 480 bytes and should sup-
                       port messages up to 2048 bytes.  By default, sudoers
                       creates log messages up to 980 bytes which corresponds
                       to the historic BSD syslog implementation which used a
                       1024 byte buffer to store the message, date, hostname
                       and program name.  To prevent syslog messages from
                       being truncated, sudoers will split up log messages
                       that are larger than syslog_maxlen bytes.  When a mes-
                       sage is split, additional parts will include the string
                       ``(command continued)'' after the user name and before
                       the continued command line arguments.

                       This setting is only supported by version 1.8.19 or
                       higher.

     Integers that can be used in a boolean context:

     loglinelen        Number of characters per line for the file log.  This
                       value is used to decide when to wrap lines for nicer
                       log files.  This has no effect on the syslog log file,
                       only the file log.  The default is 80 (use 0 or negate
                       the option to disable word wrap).

     passwd_timeout    Number of minutes before the sudo password prompt times
                       out, or 0 for no timeout.  The timeout may include a
                       fractional component if minute granularity is insuffi-
                       cient, for example 2.5.  The default is 5.

     timestamp_timeout
                       Number of minutes that can elapse before sudo will ask
                       for a passwd again.  The timeout may include a frac-
                       tional component if minute granularity is insufficient,
                       for example 2.5.  The default is 5.  Set this to 0 to
                       always prompt for a password.  If set to a value less
                       than 0 the user's time stamp will not expire until the
                       system is rebooted.  This can be used to allow users to
                       create or delete their own time stamps via ``sudo -v''
                       and ``sudo -k'' respectively.

     umask             Umask to use when running the command.  Negate this
                       option or set it to 0777 to preserve the user's umask.
                       The actual umask that is used will be the union of the
                       user's umask and the value of the umask option, which
                       defaults to 0022.  This guarantees that sudo never low-
                       ers the umask when running a command.  Note: on systems
                       that use PAM, the default PAM configuration may specify
                       its own umask which will override the value set in
                       sudoers.

     Strings:

     badpass_message   Message that is displayed if a user enters an incorrect
                       password.  The default is Sorry, try again. unless
                       insults are enabled.

     editor            A colon (`:') separated list of editors allowed to be
                       used with visudo.  visudo will choose the editor that
                       matches the user's EDITOR or VISUAL environment vari-
                       able if possible, or the first editor in the list that
                       exists and is executable.  Note that the EDITOR and
                       VISUAL environment variables are not preserved by
                       default when the env_reset option is enabled.  The
                       default is vi.

     iolog_dir         The top-level directory to use when constructing the
                       path name for the input/output log directory.  Only
                       used if the log_input or log_output options are enabled
                       or when the LOG_INPUT or LOG_OUTPUT tags are present
                       for a command.  The session sequence number, if any, is
                       stored in the directory.  The default is
                       /var/log/sudo-io.

                       The following percent (`%') escape sequences are sup-
                       ported:

                       %{seq}
                             expanded to a monotonically increasing base-36
                             sequence number, such as 0100A5, where every two
                             digits are used to form a new directory, e.g.
                             01/00/A5

                       %{user}
                             expanded to the invoking user's login name

                       %{group}
                             expanded to the name of the invoking user's real
                             group ID

                       %{runas_user}
                             expanded to the login name of the user the com-
                             mand will be run as (e.g. root)

                       %{runas_group}
                             expanded to the group name of the user the com-
                             mand will be run as (e.g. wheel)

                       %{hostname}
                             expanded to the local host name without the
                             domain name

                       %{command}
                             expanded to the base name of the command being
                             run

                       In addition, any escape sequences supported by the sys-
                       tem's strftime(3) function will be expanded.

                       To include a literal `%' character, the string `%%'
                       should be used.

     iolog_file        The path name, relative to iolog_dir, in which to store
                       input/output logs when the log_input or log_output
                       options are enabled or when the LOG_INPUT or LOG_OUTPUT
                       tags are present for a command.  Note that iolog_file
                       may contain directory components.  The default is
                       ``%{seq}''.

                       See the iolog_dir option above for a list of supported
                       percent (`%') escape sequences.

                       In addition to the escape sequences, path names that
                       end in six or more Xs will have the Xs replaced with a
                       unique combination of digits and letters, similar to
                       the mktemp(3) function.

                       If the path created by concatenating iolog_dir and
                       iolog_file already exists, the existing I/O log file
                       will be truncated and overwritten unless iolog_file
                       ends in six or more Xs.

     iolog_flush       If set, sudo will flush I/O log data to disk after each
                       write instead of buffering it.  This makes it possible
                       to view the logs in real-time as the program is execut-
                       ing but may significantly reduce the effectiveness of
                       I/O log compression.  This flag is off by default.

                       This setting is only supported by version 1.8.20 or
                       higher.

     iolog_group       The group name to look up when setting the group ID on
                       new I/O log files and directories.  If iolog_group is
                       not set, the primary group ID of the user specified by
                       iolog_user is used.  If neither iolog_group nor
                       iolog_user are set, I/O log files and directories are
                       created with group ID 0.

                       This setting is only supported by version 1.8.19 or
                       higher.

     iolog_mode        The file mode to use when creating I/O log files.  Mode
                       bits for read and write permissions for owner, group or
                       other are honored, everything else is ignored.  The
                       file permissions will always include the owner read and
                       write bits, even if they are not present in the speci-
                       fied mode.  When creating I/O log directories, search
                       (execute) bits are added to to match the read and write
                       bits specified by iolog_mode.  Defaults to 0600 (read
                       and write by user only).

                       This setting is only supported by version 1.8.19 or
                       higher.

     iolog_user        The user name to look up when setting the user and
                       group IDs on new I/O log files and directories.  If
                       iolog_group is set, it will be used instead of the
                       user's primary group ID.  By default, I/O log files and
                       directories are created with user and group ID 0.

                       This setting can be useful when the I/O logs are stored
                       on a Network File System (NFS) share.  Having a dedi-
                       cated user own the I/O log files means that sudoers
                       does not write to the log files as user ID 0, which is
                       usually not permitted by NFS.

                       This setting is only supported by version 1.8.19 or
                       higher.

     lecture_status_dir
                       The directory in which sudo stores per-user lecture
                       status files.  Once a user has received the lecture, a
                       zero-length file is created in this directory so that
                       sudo will not lecture the user again.  This directory
                       should not be cleared when the system reboots.  The
                       default is /var/db/sudo/lectured.

     mailsub           Subject of the mail sent to the mailto user.  The
                       escape %h will expand to the host name of the machine.
                       Default is ``*** SECURITY information for %h ***''.

     noexec_file       As of sudo version 1.8.1 this option is no longer sup-
                       ported.  The path to the noexec file should now be set
                       in the sudo.conf(5) file.

     pam_login_service
                       On systems that use PAM for authentication, this is the
                       service name used when the -i option is specified.  The
                       default value is ``sudo''.  See the description of
                       pam_service for more information.

                       This setting is only supported by version 1.8.8 or
                       higher.

     pam_service       On systems that use PAM for authentication, the service
                       name specifies the PAM policy to apply.  This usually
                       corresponds to an entry in the pam.conf file or a file
                       in the /etc/pam.d directory.  The default value is
                       ``sudo''.

                       This setting is only supported by version 1.8.8 or
                       higher.

     passprompt        The default prompt to use when asking for a password;
                       can be overridden via the -p option or the SUDO_PROMPT
                       environment variable.  The following percent (`%')
                       escape sequences are supported:

                       %H    expanded to the local host name including the
                             domain name (only if the machine's host name is
                             fully qualified or the fqdn option is set)

                       %h    expanded to the local host name without the
                             domain name

                       %p    expanded to the user whose password is being
                             asked for (respects the rootpw, targetpw and
                             runaspw flags in sudoers)

                       %U    expanded to the login name of the user the com-
                             mand will be run as (defaults to root)

                       %u    expanded to the invoking user's login name

                       %%    two consecutive % characters are collapsed into a
                             single % character

                       The default value is ``Password:''.

     runas_default     The default user to run commands as if the -u option is
                       not specified on the command line.  This defaults to
                       root.

     sudoers_locale    Locale to use when parsing the sudoers file, logging
                       commands, and sending email.  Note that changing the
                       locale may affect how sudoers is interpreted.  Defaults
                       to ``C''.

     timestampdir      The directory in which sudo stores its time stamp
                       files.  This directory should be cleared when the sys-
                       tem reboots.  The default is /var/run/sudo/ts.

     timestampowner    The owner of the lecture status directory, time stamp
                       directory and all files stored therein.  The default is
                       root.

     Strings that can be used in a boolean context:

     env_file      The env_file option specifies the fully qualified path to a
                   file containing variables to be set in the environment of
                   the program being run.  Entries in this file should either
                   be of the form ``VARIABLE=value'' or ``export
                   VARIABLE=value''.  The value may optionally be surrounded
                   by single or double quotes.  Variables in this file are
                   only added if the variable does not already exist in the
                   environment.  This file is considered to be part of the
                   security policy, its contents are not subject to other sudo
                   environment restrictions such as env_keep and env_check.

     exempt_group  Users in this group are exempt from password and PATH
                   requirements.  The group name specified should not include
                   a % prefix.  This is not set by default.

     fdexec        Determines whether sudo will execute a command by its path
                   or by an open file descriptor.  It has the following possi-
                   ble values:

                   always  Always execute by file descriptor.

                   never   Never execute by file descriptor.

                   digest_only
                           Only execute by file descriptor if the command has
                           an associated digest in the sudoers file.

                   The default value is digest_only.  This avoids a time of
                   check versus time of use race condition when the command is
                   located in a directory writable by the invoking user.

                   Note that fdexec will change the first element of the argu-
                   ment vector for scripts ($0 in the shell) due to the way
                   the kernel runs script interpreters.  Instead of being a
                   normal path, it will refer to a file descriptor.  For exam-
                   ple, /dev/fd/4 on Solaris and /proc/self/fd/4 on Linux.  A
                   workaround is to use the SUDO_COMMAND environment variable
                   instead.

                   The fdexec setting is only used when the command is matched
                   by path name.  It has no effect if the command is matched
                   by the built-in ALL alias.

                   This setting is only supported by version 1.8.20 or higher.
                   If the operating system does not support the fexecve(2)
                   system call, this setting has no effect.

     group_plugin  A string containing a sudoers group plugin with optional
                   arguments.  The string should consist of the plugin path,
                   either fully-qualified or relative to the /usr/pkg/lib/sudo
                   directory, followed by any configuration arguments the
                   plugin requires.  These arguments (if any) will be passed
                   to the plugin's initialization function.  If arguments are
                   present, the string must be enclosed in double quotes ("").

                   For more information see GROUP PROVIDER PLUGINS.

     lecture       This option controls when a short lecture will be printed
                   along with the password prompt.  It has the following pos-
                   sible values:

                   always  Always lecture the user.

                   never   Never lecture the user.

                   once    Only lecture the user the first time they run sudo.

                   If no value is specified, a value of once is implied.
                   Negating the option results in a value of never being used.
                   The default value is once.

     lecture_file  Path to a file containing an alternate sudo lecture that
                   will be used in place of the standard lecture if the named
                   file exists.  By default, sudo uses a built-in lecture.

     listpw        This option controls when a password will be required when
                   a user runs sudo with the -l option.  It has the following
                   possible values:

                   all       All the user's sudoers file entries for the cur-
                             rent host must have the NOPASSWD flag set to
                             avoid entering a password.

                   always    The user must always enter a password to use the
                             -l option.

                   any       At least one of the user's sudoers file entries
                             for the current host must have the NOPASSWD flag
                             set to avoid entering a password.

                   never     The user need never enter a password to use the
                             -l option.

                   If no value is specified, a value of any is implied.
                   Negating the option results in a value of never being used.
                   The default value is any.

     logfile       Path to the sudo log file (not the syslog log file).  Set-
                   ting a path turns on logging to a file; negating this
                   option turns it off.  By default, sudo logs via syslog.

     mailerflags   Flags to use when invoking mailer. Defaults to -t.

     mailerpath    Path to mail program used to send warning mail.  Defaults
                   to the path to sendmail found at configure time.

     mailfrom      Address to use for the ``from'' address when sending warn-
                   ing and error mail.  The address should be enclosed in dou-
                   ble quotes ("") to protect against sudo interpreting the @
                   sign.  Defaults to the name of the user running sudo.

     mailto        Address to send warning and error mail to.  The address
                   should be enclosed in double quotes ("") to protect against
                   sudo interpreting the @ sign.  Defaults to root.

     restricted_env_file
                   The restricted_env_file option specifies the fully quali-
                   fied path to a file containing variables to be set in the
                   environment of the program being run.  Entries in this file
                   should either be of the form ``VARIABLE=value'' or ``export
                   VARIABLE=value''.  The value may optionally be surrounded
                   by single or double quotes.  Variables in this file are
                   only added if the variable does not already exist in the
                   environment.  Unlike env_file, the file's contents are not
                   trusted and are processed in a manner similar to that of
                   the invoking user's environment.  If env_reset is enabled,
                   variables in the file will only be added if they are
                   matched by either the env_check or env_keep list.  If
                   env_reset is disabled, variables in the file are added as
                   long as they are not matched by the env_delete list.  In
                   either case, the contents of restricted_env_file are pro-
                   cessed before the contents of env_file.

     secure_path   Path used for every command run from sudo.  If you don't
                   trust the people running sudo to have a sane PATH environ-
                   ment variable you may want to use this.  Another use is if
                   you want to have the ``root path'' be separate from the
                   ``user path''.  Users in the group specified by the
                   exempt_group option are not affected by secure_path.  This
                   option is not set by default.

     syslog        Syslog facility if syslog is being used for logging (negate
                   to disable syslog logging).  Defaults to authpriv.

                   The following syslog facilities are supported: authpriv (if
                   your OS supports it), auth, daemon, user, local0, local1,
                   local2, local3, local4, local5, local6, and local7.

     syslog_badpri
                   Syslog priority to use when the user is not allowed to run
                   a command or when authentication is unsuccessful.  Defaults
                   to alert.

                   The following syslog priorities are supported: alert, crit,
                   debug, emerg, err, info, notice, warning, and none.  Negat-
                   ing the option or setting it to a value of none will dis-
                   able logging of unsuccessful commands.

     syslog_goodpri
                   Syslog priority to use when the user is allowed to run a
                   command and authentication is successful.  Defaults to
                   notice.

                   See syslog_badpri for the list of supported syslog priori-
                   ties.  Negating the option or setting it to a value of none
                   will disable logging of successful commands.

     verifypw      This option controls when a password will be required when
                   a user runs sudo with the -v option.  It has the following
                   possible values:

                   all     All the user's sudoers file entries for the current
                           host must have the NOPASSWD flag set to avoid
                           entering a password.

                   always  The user must always enter a password to use the -v
                           option.

                   any     At least one of the user's sudoers file entries for
                           the current host must have the NOPASSWD flag set to
                           avoid entering a password.

                   never   The user need never enter a password to use the -v
                           option.

                   If no value is specified, a value of all is implied.
                   Negating the option results in a value of never being used.
                   The default value is all.

     Lists that can be used in a boolean context:

     env_check         Environment variables to be removed from the user's
                       environment unless they are considered ``safe''.  For
                       all variables except TZ, ``safe'' means that the vari-
                       able's value does not contain any `%' or `/' charac-
                       ters.  This can be used to guard against printf-style
                       format vulnerabilities in poorly-written programs.  The
                       TZ variable is considered unsafe if any of the follow-
                       ing are true:

                          It consists of a fully-qualified path name, option-
                           ally prefixed with a colon (`:'), that does not
                           match the location of the zoneinfo directory.

                          It contains a .. path element.

                          It contains white space or non-printable charac-
                           ters.

                          It is longer than the value of PATH_MAX.

                       The argument may be a double-quoted, space-separated
                       list or a single value without double-quotes.  The list
                       can be replaced, added to, deleted from, or disabled by
                       using the =, +=, -=, and ! operators respectively.
                       Regardless of whether the env_reset option is enabled
                       or disabled, variables specified by env_check will be
                       preserved in the environment if they pass the aforemen-
                       tioned check.  The global list of environment variables
                       to check is displayed when sudo is run by root with the
                       -V option.

     env_delete        Environment variables to be removed from the user's
                       environment when the env_reset option is not in effect.
                       The argument may be a double-quoted, space-separated
                       list or a single value without double-quotes.  The list
                       can be replaced, added to, deleted from, or disabled by
                       using the =, +=, -=, and ! operators respectively.  The
                       global list of environment variables to remove is dis-
                       played when sudo is run by root with the -V option.
                       Note that many operating systems will remove poten-
                       tially dangerous variables from the environment of any
                       setuid process (such as sudo).

     env_keep          Environment variables to be preserved in the user's
                       environment when the env_reset option is in effect.
                       This allows fine-grained control over the environment
                       sudo-spawned processes will receive.  The argument may
                       be a double-quoted, space-separated list or a single
                       value without double-quotes.  The list can be replaced,
                       added to, deleted from, or disabled by using the =, +=,
                       -=, and ! operators respectively.  The global list of
                       variables to keep is displayed when sudo is run by root
                       with the -V option.

GROUP PROVIDER PLUGINS
     The sudoers plugin supports its own plugin interface to allow non-Unix
     group lookups which can query a group source other than the standard Unix
     group database.  This can be used to implement support for the
     nonunix_group syntax described earlier.

     Group provider plugins are specified via the group_plugin Defaults set-
     ting.  The argument to group_plugin should consist of the plugin path,
     either fully-qualified or relative to the /usr/pkg/lib/sudo directory,
     followed by any configuration options the plugin requires.  These options
     (if specified) will be passed to the plugin's initialization function.
     If options are present, the string must be enclosed in double quotes
     ("").

     The following group provider plugins are installed by default:

     group_file
               The group_file plugin supports an alternate group file that
               uses the same syntax as the /etc/group file.  The path to the
               group file should be specified as an option to the plugin.  For
               example, if the group file to be used is /etc/sudo-group:

               Defaults group_plugin="group_file.so /etc/sudo-group"

     system_group
               The system_group plugin supports group lookups via the standard
               C library functions getgrnam() and getgrid().  This plugin can
               be used in instances where the user belongs to groups not
               present in the user's supplemental group vector.  This plugin
               takes no options:

               Defaults group_plugin=system_group.so

     The group provider plugin API is described in detail in sudo_plugin(8).

LOG FORMAT
     sudoers can log events using either syslog(3) or a simple log file.  The
     log format is almost identical in both cases.

   Accepted command log entries
     Commands that sudo runs are logged using the following format (split into
     multiple lines for readability):

         date hostname progname: username : TTY=ttyname ; PWD=cwd ; \
             USER=runasuser ; GROUP=runasgroup ; TSID=logid ; \
             ENV=env_vars COMMAND=command

     Where the fields are as follows:

     date          The date the command was run.  Typically, this is in the
                   format ``MMM, DD, HH:MM:SS''.  If logging via syslog(3),
                   the actual date format is controlled by the syslog daemon.
                   If logging to a file and the log_year option is enabled,
                   the date will also include the year.

     hostname      The name of the host sudo was run on.  This field is only
                   present when logging via syslog(3).

     progname      The name of the program, usually sudo or sudoedit.  This
                   field is only present when logging via syslog(3).

     username      The login name of the user who ran sudo.

     ttyname       The short name of the terminal (e.g. ``console'',
                   ``tty01'', or ``pts/0'') sudo was run on, or ``unknown'' if
                   there was no terminal present.

     cwd           The current working directory that sudo was run in.

     runasuser     The user the command was run as.

     runasgroup    The group the command was run as if one was specified on
                   the command line.

     logid         An I/O log identifier that can be used to replay the com-
                   mand's output.  This is only present when the log_input or
                   log_output option is enabled.

     env_vars      A list of environment variables specified on the command
                   line, if specified.

     command       The actual command that was executed.

     Messages are logged using the locale specified by sudoers_locale, which
     defaults to the ``C'' locale.

   Denied command log entries
     If the user is not allowed to run the command, the reason for the denial
     will follow the user name.  Possible reasons include:

     user NOT in sudoers
       The user is not listed in the sudoers file.

     user NOT authorized on host
       The user is listed in the sudoers file but is not allowed to run com-
       mands on the host.

     command not allowed
       The user is listed in the sudoers file for the host but they are not
       allowed to run the specified command.

     3 incorrect password attempts
       The user failed to enter their password after 3 tries.  The actual num-
       ber of tries will vary based on the number of failed attempts and the
       value of the passwd_tries option.

     a password is required
       sudo's -n option was specified but a password was required.

     sorry, you are not allowed to set the following environment variables
       The user specified environment variables on the command line that were
       not allowed by sudoers.

   Error log entries
     If an error occurs, sudoers will log a message and, in most cases, send a
     message to the administrator via email.  Possible errors include:

     parse error in /etc/sudoers near line N
       sudoers encountered an error when parsing the specified file.  In some
       cases, the actual error may be one line above or below the line number
       listed, depending on the type of error.

     problem with defaults entries
       The sudoers file contains one or more unknown Defaults settings.  This
       does not prevent sudo from running, but the sudoers file should be
       checked using visudo.

     timestamp owner (username): No such user
       The time stamp directory owner, as specified by the timestampowner set-
       ting, could not be found in the password database.

     unable to open/read /etc/sudoers
       The sudoers file could not be opened for reading.  This can happen when
       the sudoers file is located on a remote file system that maps user ID 0
       to a different value.  Normally, sudoers tries to open the sudoers file
       using group permissions to avoid this problem.  Consider either chang-
       ing the ownership of /etc/sudoers or adding an argument like
       ``sudoers_uid=N'' (where `N' is the user ID that owns the sudoers file)
       to the end of the sudoers Plugin line in the sudo.conf(5) file.

     unable to stat /etc/sudoers
       The /etc/sudoers file is missing.

     /etc/sudoers is not a regular file
       The /etc/sudoers file exists but is not a regular file or symbolic
       link.

     /etc/sudoers is owned by uid N, should be 0
       The sudoers file has the wrong owner.  If you wish to change the
       sudoers file owner, please add ``sudoers_uid=N'' (where `N' is the user
       ID that owns the sudoers file) to the sudoers Plugin line in the
       sudo.conf(5) file.

     /etc/sudoers is world writable
       The permissions on the sudoers file allow all users to write to it.
       The sudoers file must not be world-writable, the default file mode is
       0440 (readable by owner and group, writable by none).  The default mode
       may be changed via the ``sudoers_mode'' option to the sudoers Plugin
       line in the sudo.conf(5) file.

     /etc/sudoers is owned by gid N, should be 1
       The sudoers file has the wrong group ownership.  If you wish to change
       the sudoers file group ownership, please add ``sudoers_gid=N'' (where
       `N' is the group ID that owns the sudoers file) to the sudoers Plugin
       line in the sudo.conf(5) file.

     unable to open /var/run/sudo/ts/username
       sudoers was unable to read or create the user's time stamp file.  This
       can happen when timestampowner is set to a user other than root and the
       mode on /var/run/sudo is not searchable by group or other.  The default
       mode for /var/run/sudo is 0711.

     unable to write to /var/run/sudo/ts/username
       sudoers was unable to write to the user's time stamp file.

     /var/run/sudo/ts is owned by uid X, should be Y
       The time stamp directory is owned by a user other than timestampowner.
       This can occur when the value of timestampowner has been changed.
       sudoers will ignore the time stamp directory until the owner is cor-
       rected.

     /var/run/sudo/ts is group writable
       The time stamp directory is group-writable; it should be writable only
       by timestampowner.  The default mode for the time stamp directory is
       0700.  sudoers will ignore the time stamp directory until the mode is
       corrected.

   Notes on logging via syslog
     By default, sudoers logs messages via syslog(3).  The date, hostname, and
     progname fields are added by the system's syslog() function, not sudoers
     itself.  As such, they may vary in format on different systems.

     The maximum size of syslog messages varies from system to system.  The
     syslog_maxlen setting can be used to change the maximum syslog message
     size from the default value of 980 bytes.  For more information, see the
     description of syslog_maxlen.

   Notes on logging to a file
     If the logfile option is set, sudoers will log to a local file, such as
     /var/log/sudo.  When logging to a file, sudoers uses a format similar to
     syslog(3), with a few important differences:

     1.   The progname and hostname fields are not present.

     2.   If the log_year option is enabled, the date will also include the
          year.

     3.   Lines that are longer than loglinelen characters (80 by default) are
          word-wrapped and continued on the next line with a four character
          indent.  This makes entries easier to read for a human being, but
          makes it more difficult to use grep(1) on the log files.  If the
          loglinelen option is set to 0 (or negated with a `!'), word wrap
          will be disabled.

I/O LOG FILES
     When I/O logging is enabled, sudo will run the command in a pseudo-tty
     and log all user input and/or output.  I/O is logged to the directory
     specified by the iolog_dir option (/var/log/sudo-io by default) using a
     unique session ID that is included in the sudo log line, prefixed with
     ``TSID=''.  The iolog_file option may be used to control the format of
     the session ID.

     Each I/O log is stored in a separate directory that contains the follow-
     ing files:

     log       a text file containing the time the command was run, the name
               of the user who ran sudo, the name of the target user, the name
               of the target group (optional), the terminal that sudo was run
               from, the number of rows and columns of the terminal, the work-
               ing directory the command was run from and the path name of the
               command itself (with arguments if present)

     timing    a log of the amount of time between, and the number of bytes
               in, each I/O log entry (used for session playback)

     ttyin     input from the user's tty (what the user types)

     stdin     input from a pipe or file

     ttyout    output from the pseudo-tty (what the command writes to the
               screen)

     stdout    standard output to a pipe or redirected to a file

     stderr    standard error to a pipe or redirected to a file

     All files other than log are compressed in gzip format unless the
     compress_io flag has been disabled.  Due to buffering, it is not normally
     possible to display the I/O logs in real-time as the program is executing
     The I/O log data will not be complete until the program run by sudo has
     exited or has been terminated by a signal.  The iolog_flush flag can be
     used to disable buffering, in which case I/O log data is written to disk
     as soon as it is available.  The output portion of an I/O log file can be
     viewed with the sudoreplay(8) utility, which can also be used to list or
     search the available logs.

     Note that user input may contain sensitive information such as passwords
     (even if they are not echoed to the screen), which will be stored in the
     log file unencrypted.  In most cases, logging the command output via
     log_output or LOG_OUTPUT is all that is required.

     Since each session's I/O logs are stored in a separate directory, tradi-
     tional log rotation utilities cannot be used to limit the number of I/O
     logs.  The simplest way to limit the number of I/O is by setting the
     maxseq option to the maximum number of logs you wish to store.  Once the
     I/O log sequence number reaches maxseq, it will be reset to zero and
     sudoers will truncate and re-use any existing I/O logs.

FILES
     /etc/sudo.conf            Sudo front end configuration

     /etc/sudoers              List of who can run what

     /etc/group                Local groups file

     /etc/netgroup             List of network groups

     /var/log/sudo-io          I/O log files

     /var/run/sudo/ts          Directory containing time stamps for the
                               sudoers security policy

     /var/db/sudo/lectured     Directory containing lecture status files for
                               the sudoers security policy

     /etc/environment          Initial environment for -i mode on AIX and
                               Linux systems

EXAMPLES
     Below are example sudoers file entries.  Admittedly, some of these are a
     bit contrived.  First, we allow a few environment variables to pass and
     then define our aliases:

     # Run X applications through sudo; HOME is used to find the
     # .Xauthority file.  Note that other programs use HOME to find
     # configuration files and this may lead to privilege escalation!
     Defaults env_keep += "DISPLAY HOME"

     # User alias specification
     User_Alias      FULLTIMERS = millert, mikef, dowdy
     User_Alias      PARTTIMERS = bostley, jwfox, crawl
     User_Alias      WEBMASTERS = will, wendy, wim

     # Runas alias specification
     Runas_Alias     OP = root, operator
     Runas_Alias     DB = oracle, sybase
     Runas_Alias     ADMINGRP = adm, oper

     # Host alias specification
     Host_Alias      SPARC = bigtime, eclipse, moet, anchor :\
                     SGI = grolsch, dandelion, black :\
                     ALPHA = widget, thalamus, foobar :\
                     HPPA = boa, nag, python
     Host_Alias      CUNETS = 128.138.0.0/255.255.0.0
     Host_Alias      CSNETS = 128.138.243.0, 128.138.204.0/24, 128.138.242.0
     Host_Alias      SERVERS = master, mail, www, ns
     Host_Alias      CDROM = orion, perseus, hercules

     # Cmnd alias specification
     Cmnd_Alias      DUMPS = /usr/bin/mt, /usr/sbin/dump, /usr/sbin/rdump,\
                             /usr/sbin/restore, /usr/sbin/rrestore,\
                             sha224:0GomF8mNN3wlDt1HD9XldjJ3SNgpFdbjO1+NsQ== \
                             /home/operator/bin/start_backups
     Cmnd_Alias      KILL = /usr/bin/kill
     Cmnd_Alias      PRINTING = /usr/sbin/lpc, /usr/bin/lprm
     Cmnd_Alias      SHUTDOWN = /usr/sbin/shutdown
     Cmnd_Alias      HALT = /usr/sbin/halt
     Cmnd_Alias      REBOOT = /usr/sbin/reboot
     Cmnd_Alias      SHELLS = /usr/bin/sh, /usr/bin/csh, /usr/bin/ksh,\
                              /usr/local/bin/tcsh, /usr/bin/rsh,\
                              /usr/local/bin/zsh
     Cmnd_Alias      SU = /usr/bin/su
     Cmnd_Alias      PAGERS = /usr/bin/more, /usr/bin/pg, /usr/bin/less

     Here we override some of the compiled in default values.  We want sudo to
     log via syslog(3) using the auth facility in all cases.  We don't want to
     subject the full time staff to the sudo lecture, user millert need not
     give a password, and we don't want to reset the LOGNAME, USER or USERNAME
     environment variables when running commands as root.  Additionally, on
     the machines in the SERVERS Host_Alias, we keep an additional local log
     file and make sure we log the year in each log line since the log entries
     will be kept around for several years.  Lastly, we disable shell escapes
     for the commands in the PAGERS Cmnd_Alias (/usr/bin/more, /usr/bin/pg and
     /usr/bin/less).  Note that this will not effectively constrain users with
     sudo ALL privileges.

     # Override built-in defaults
     Defaults                syslog=auth
     Defaults>root           !set_logname
     Defaults:FULLTIMERS     !lecture
     Defaults:millert        !authenticate
     Defaults@SERVERS        log_year, logfile=/var/log/sudo.log
     Defaults!PAGERS         noexec

     The User specification is the part that actually determines who may run
     what.

     root            ALL = (ALL) ALL
     %wheel          ALL = (ALL) ALL

     We let root and any user in group wheel run any command on any host as
     any user.

     FULLTIMERS      ALL = NOPASSWD: ALL

     Full time sysadmins (millert, mikef, and dowdy) may run any command on
     any host without authenticating themselves.

     PARTTIMERS      ALL = ALL

     Part time sysadmins bostley, jwfox, and crawl) may run any command on any
     host but they must authenticate themselves first (since the entry lacks
     the NOPASSWD tag).

     jack            CSNETS = ALL

     The user jack may run any command on the machines in the CSNETS alias
     (the networks 128.138.243.0, 128.138.204.0, and 128.138.242.0).  Of those
     networks, only 128.138.204.0 has an explicit netmask (in CIDR notation)
     indicating it is a class C network.  For the other networks in CSNETS,
     the local machine's netmask will be used during matching.

     lisa            CUNETS = ALL

     The user lisa may run any command on any host in the CUNETS alias (the
     class B network 128.138.0.0).

     operator        ALL = DUMPS, KILL, SHUTDOWN, HALT, REBOOT, PRINTING,\
                     sudoedit /etc/printcap, /usr/oper/bin/

     The operator user may run commands limited to simple maintenance.  Here,
     those are commands related to backups, killing processes, the printing
     system, shutting down the system, and any commands in the directory
     /usr/oper/bin/.  Note that one command in the DUMPS Cmnd_Alias includes a
     sha224 digest, /home/operator/bin/start_backups.  This is because the
     directory containing the script is writable by the operator user.  If the
     script is modified (resulting in a digest mismatch) it will no longer be
     possible to run it via sudo.

     joe             ALL = /usr/bin/su operator

     The user joe may only su(1) to operator.

     pete            HPPA = /usr/bin/passwd [A-Za-z]*, !/usr/bin/passwd *root*

     %opers          ALL = (: ADMINGRP) /usr/sbin/

     Users in the opers group may run commands in /usr/sbin/ as themselves
     with any group in the ADMINGRP Runas_Alias (the adm and oper groups).

     The user pete is allowed to change anyone's password except for root on
     the HPPA machines.  Because command line arguments are matched as a sin-
     gle, concatenated string, the `*' wildcard will match multiple words.
     This example assumes that passwd(1) does not take multiple user names on
     the command line.  Note that on GNU systems, options to passwd(1) may be
     specified after the user argument.  As a result, this rule will also
     allow:

         passwd username --expire

     which may not be desirable.

     bob             SPARC = (OP) ALL : SGI = (OP) ALL

     The user bob may run anything on the SPARC and SGI machines as any user
     listed in the OP Runas_Alias (root and operator.)

     jim             +biglab = ALL

     The user jim may run any command on machines in the biglab netgroup.
     sudo knows that ``biglab'' is a netgroup due to the `+' prefix.

     +secretaries    ALL = PRINTING, /usr/bin/adduser, /usr/bin/rmuser

     Users in the secretaries netgroup need to help manage the printers as
     well as add and remove users, so they are allowed to run those commands
     on all machines.

     fred            ALL = (DB) NOPASSWD: ALL

     The user fred can run commands as any user in the DB Runas_Alias (oracle
     or sybase) without giving a password.

     john            ALPHA = /usr/bin/su [!-]*, !/usr/bin/su *root*

     On the ALPHA machines, user john may su to anyone except root but he is
     not allowed to specify any options to the su(1) command.

     jen             ALL, !SERVERS = ALL

     The user jen may run any command on any machine except for those in the
     SERVERS Host_Alias (master, mail, www and ns).

     jill            SERVERS = /usr/bin/, !SU, !SHELLS

     For any machine in the SERVERS Host_Alias, jill may run any commands in
     the directory /usr/bin/ except for those commands belonging to the SU and
     SHELLS Cmnd_Aliases.  While not specifically mentioned in the rule, the
     commands in the PAGERS Cmnd_Alias all reside in /usr/bin and have the
     noexec option set.

     steve           CSNETS = (operator) /usr/local/op_commands/

     The user steve may run any command in the directory /usr/local/op_com-
     mands/ but only as user operator.

     matt            valkyrie = KILL

     On his personal workstation, valkyrie, matt needs to be able to kill hung
     processes.

     WEBMASTERS      www = (www) ALL, (root) /usr/bin/su www

     On the host www, any user in the WEBMASTERS User_Alias (will, wendy, and
     wim), may run any command as user www (which owns the web pages) or sim-
     ply su(1) to www.

     ALL             CDROM = NOPASSWD: /sbin/umount /CDROM,\
                     /sbin/mount -o nosuid\,nodev /dev/cd0a /CDROM

     Any user may mount or unmount a CD-ROM on the machines in the CDROM
     Host_Alias (orion, perseus, hercules) without entering a password.  This
     is a bit tedious for users to type, so it is a prime candidate for encap-
     sulating in a shell script.

SECURITY NOTES
   Limitations of the `!' operator
     It is generally not effective to ``subtract'' commands from ALL using the
     `!' operator.  A user can trivially circumvent this by copying the
     desired command to a different name and then executing that.  For exam-
     ple:

     bill    ALL = ALL, !SU, !SHELLS

     Doesn't really prevent bill from running the commands listed in SU or
     SHELLS since he can simply copy those commands to a different name, or
     use a shell escape from an editor or other program.  Therefore, these
     kind of restrictions should be considered advisory at best (and rein-
     forced by policy).

     In general, if a user has sudo ALL there is nothing to prevent them from
     creating their own program that gives them a root shell (or making their
     own copy of a shell) regardless of any `!' elements in the user specifi-
     cation.

   Security implications of fast_glob
     If the fast_glob option is in use, it is not possible to reliably negate
     commands where the path name includes globbing (aka wildcard) characters.
     This is because the C library's fnmatch(3) function cannot resolve rela-
     tive paths.  While this is typically only an inconvenience for rules that
     grant privileges, it can result in a security issue for rules that sub-
     tract or revoke privileges.

     For example, given the following sudoers file entry:

     john    ALL = /usr/bin/passwd [a-zA-Z0-9]*, /usr/bin/chsh [a-zA-Z0-9]*,\
                   /usr/bin/chfn [a-zA-Z0-9]*, !/usr/bin/* root

     User john can still run /usr/bin/passwd root if fast_glob is enabled by
     changing to /usr/bin and running ./passwd root instead.

   Preventing shell escapes
     Once sudo executes a program, that program is free to do whatever it
     pleases, including run other programs.  This can be a security issue
     since it is not uncommon for a program to allow shell escapes, which lets
     a user bypass sudo's access control and logging.  Common programs that
     permit shell escapes include shells (obviously), editors, paginators,
     mail and terminal programs.

     There are two basic approaches to this problem:

     restrict  Avoid giving users access to commands that allow the user to
               run arbitrary commands.  Many editors have a restricted mode
               where shell escapes are disabled, though sudoedit is a better
               solution to running editors via sudo.  Due to the large number
               of programs that offer shell escapes, restricting users to the
               set of programs that do not is often unworkable.

     noexec    Many systems that support shared libraries have the ability to
               override default library functions by pointing an environment
               variable (usually LD_PRELOAD) to an alternate shared library.
               On such systems, sudo's noexec functionality can be used to
               prevent a program run by sudo from executing any other pro-
               grams.  Note, however, that this applies only to native dynami-
               cally-linked executables.  Statically-linked executables and
               foreign executables running under binary emulation are not
               affected.

               The noexec feature is known to work on SunOS, Solaris, *BSD,
               Linux, IRIX, Tru64 UNIX, MacOS X, HP-UX 11.x and AIX 5.3 and
               above.  It should be supported on most operating systems that
               support the LD_PRELOAD environment variable.  Check your oper-
               ating system's manual pages for the dynamic linker (usually
               ld.so, ld.so.1, dyld, dld.sl, rld, or loader) to see if
               LD_PRELOAD is supported.

               To enable noexec for a command, use the NOEXEC tag as docu-
               mented in the User Specification section above.  Here is that
               example again:

               aaron   shanty = NOEXEC: /usr/bin/more, /usr/bin/vi

               This allows user aaron to run /usr/bin/more and /usr/bin/vi
               with noexec enabled.  This will prevent those two commands from
               executing other commands (such as a shell).  If you are unsure
               whether or not your system is capable of supporting noexec you
               can always just try it out and check whether shell escapes work
               when noexec is enabled.

     Note that restricting shell escapes is not a panacea.  Programs running
     as root are still capable of many potentially hazardous operations (such
     as changing or overwriting files) that could lead to unintended privilege
     escalation.  In the specific case of an editor, a safer approach is to
     give the user permission to run sudoedit (see below).

   Secure editing
     The sudoers plugin includes sudoedit support which allows users to
     securely edit files with the editor of their choice.  As sudoedit is a
     built-in command, it must be specified in the sudoers file without a
     leading path.  However, it may take command line arguments just as a nor-
     mal command does.  Wildcards used in sudoedit command line arguments are
     expected to be path names, so a forward slash (`/') will not be matched
     by a wildcard.

     Unlike other sudo commands, the editor is run with the permissions of the
     invoking user and with the environment unmodified.  More information may
     be found in the description of the -e option in sudo(8).

     For example, to allow user operator to edit the ``message of the day''
     file:

           operator        sudoedit /etc/motd

     The operator user then runs sudoedit as follows:

           $ sudoedit /etc/motd

     The editor will run as the operator user, not root, on a temporary copy
     of /etc/motd.  After the file has been edited, /etc/motd will be updated
     with the contents of the temporary copy.

     Users should never be granted sudoedit permission to edit a file that
     resides in a directory the user has write access to, either directly or
     via a wildcard.  If the user has write access to the directory it is pos-
     sible to replace the legitimate file with a link to another file, allow-
     ing the editing of arbitrary files.  To prevent this, starting with ver-
     sion 1.8.16, symbolic links will not be followed in writable directories
     and sudoedit will refuse to edit a file located in a writable directory
     unless the sudoedit_checkdir option has been disabled or the invoking
     user is root.  Additionally, in version 1.8.15 and higher, sudoedit will
     refuse to open a symbolic link unless either the sudoedit_follow option
     is enabled or the sudoedit command is prefixed with the FOLLOW tag in the
     sudoers file.

   Time stamp file checks
     sudoers will check the ownership of its time stamp directory
     (/var/run/sudo/ts by default) and ignore the directory's contents if it
     is not owned by root or if it is writable by a user other than root.
     Older versions of sudo stored time stamp files in /tmp; this is no longer
     recommended as it may be possible for a user to create the time stamp
     themselves on systems that allow unprivileged users to change the owner-
     ship of files they create.

     While the time stamp directory should be cleared at reboot time, not all
     systems contain a /var/run directory.  To avoid potential problems,
     sudoers will ignore time stamp files that date from before the machine
     booted on systems where the boot time is available.

     Some systems with graphical desktop environments allow unprivileged users
     to change the system clock.  Since sudoers relies on the system clock for
     time stamp validation, it may be possible on such systems for a user to
     run sudo for longer than timestamp_timeout by setting the clock back.  To
     combat this, sudoers uses a monotonic clock (which never moves backwards)
     for its time stamps if the system supports it.

     sudoers will not honor time stamps set far in the future.  Time stamps
     with a date greater than current_time + 2 * TIMEOUT will be ignored and
     sudoers will log and complain.

     Since time stamp files live in the file system, they can outlive a user's
     login session.  As a result, a user may be able to login, run a command
     with sudo after authenticating, logout, login again, and run sudo without
     authenticating so long as the record's time stamp is within 5 minutes (or
     whatever value the timeout is set to in the sudoers file).  When the
     tty_tickets option is enabled, the time stamp record includes the device
     number of the terminal the user authenticated with.  This provides per-
     tty granularity but time stamp records still may outlive the user's ses-
     sion.  The time stamp record also includes the session ID of the process
     that last authenticated.  This prevents processes in different terminal
     sessions from using the same time stamp record.  It also helps reduce the
     chance that a user will be able to run sudo without entering a password
     when logging out and back in again on the same terminal.

DEBUGGING
     Versions 1.8.4 and higher of the sudoers plugin support a flexible debug-
     ging framework that can help track down what the plugin is doing inter-
     nally if there is a problem.  This can be configured in the sudo.conf(5)
     file.

     The sudoers plugin uses the same debug flag format as the sudo front-end:
     subsystem@priority.

     The priorities used by sudoers, 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 exam-
     ple, a priority of notice would include debug messages logged at notice
     and higher.

     The following subsystems are used by the sudoers plugin:

     alias     User_Alias, Runas_Alias, Host_Alias and Cmnd_Alias processing

     all       matches every subsystem

     audit     BSM and Linux audit code

     auth      user authentication

     defaults  sudoers file Defaults settings

     env       environment handling

     ldap      LDAP-based sudoers

     logging   logging support

     match     matching of users, groups, hosts and netgroups in the sudoers
               file

     netif     network interface handling

     nss       network service switch handling in sudoers

     parser    sudoers file parsing

     perms     permission setting

     plugin    The equivalent of main for the plugin.

     pty       pseudo-tty related code

     rbtree    redblack tree internals

     sssd      SSSD-based sudoers

     util      utility functions
     For example:

     Debug sudo /var/log/sudo_debug match@info,nss@info

     For more information, see the sudo.conf(5) manual.

SEE ALSO
     ssh(1), su(1), fnmatch(3), glob(3), mktemp(3), strftime(3), sudo.conf(5),
     sudoers.ldap(5), sudo(8), sudo_plugin(8), visudo(8)

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
     (https://www.sudo.ws/contributors.html) for an exhaustive list of people
     who have contributed to sudo.

CAVEATS
     The sudoers file should always be edited by the visudo command which
     locks the file and does grammatical checking.  It is imperative that the
     sudoers file be free of syntax errors since sudo will not run with a syn-
     tactically incorrect sudoers file.

     When using netgroups of machines (as opposed to users), if you store
     fully qualified host name in the netgroup (as is usually the case), you
     either need to have the machine's host name be fully qualified as
     returned by the hostname command or use the fqdn option in sudoers.

BUGS
     If you feel you have found a bug in sudo, please submit a bug report at
     https://bugzilla.sudo.ws/

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, includ-
     ing, 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 https://www.sudo.ws/license.html for complete
     details.

Sudo 1.8.20p2                     May 8, 2017                    Sudo 1.8.20p2

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