SUDOERS(4)                   MAINTENANCE COMMANDS                   SUDOERS(4)



NAME
       sudoers - default sudo security policy module

DESCRIPTION
       The sudoers policy module 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 policy information in LDAP, please see
       sudoers.ldap(4).

   Authentication and Logging
       The sudoers security policy requires that most users authenticate
       themselves 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
       command.  Unlike su(1), when sudoers requires authentication, it
       validates the invoking user's credentials, not the target user's (or
       root's) credentials.  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 mail will not be sent if an unauthorized user tries to run
       sudo with the -l or -v option.  This allows users to determine for
       themselves whether or not they are allowed to use sudo.

       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 lookup is still done for root, not the user
       specified by SUDO_USER.

       sudoers uses time stamp files for credential caching.  Once a user has
       been authenticated, a time stamp is updated and the user may then use
       sudo without a password for a short period of time (5 minutes unless
       overridden by the timeout option.  By default, sudoers uses a tty-based
       time stamp which means that there is a separate time stamp for each of
       a user's login sessions.  The tty__tickets option can be disabled to
       force the use of a single time stamp for all of a user's sessions.

       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.

       sudoers also supports logging a command's input and output streams.
       I/O logging is not on by default but can be enabled using the log__input
       and log__output Defaults flags as well as the LOG_INPUT and LOG_OUTPUT
       command tags.

   Command Environment
       Since environment variables can influence program behavior, sudoers
       provides 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 minimal environment containing the TERM, PATH, HOME,
       MAIL, SHELL, LOGNAME, USER, USERNAME and SUDO_* variables in addition
       to variables from the invoking process permitted by the env__check and
       env__keep options.  This is effectively a whitelist for environment
       variables.

       If, however, the env__reset option is disabled, any variables not
       explicitly 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.  Since it is not possible to blacklist all
       potentially dangerous environment variables, use of the default
       env__reset behavior is encouraged.

       In all cases, environment variables with a value beginning with () are
       removed as they could be interpreted as bash functions.  The list of
       environment variables that sudo allows or denies is contained in the
       output of sudo -V when run as root.

       Note that the dynamic linker on most operating systems will remove
       variables 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 Linux and AIX systems the contents of /etc/environment are also
       included.  All other environment variables are removed.

       Lastly, if the env__file option is defined, any variables present in
       that file will be set to their specified values.

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
       necessarily the most specific match).

       The sudoers grammar will be described below in Extended Backus-Naur
       Form (EBNF).  Don't despair if you don't know what EBNF is; 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,
       confuse 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
       underscore 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

       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 '%#'
       respectively), 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.

       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
       characters.  Alternately, special characters may be specified in
       escaped hex mode, e.g. \x20 for space.  When using double quotes, any
       prefix characters must be included inside the quotes.

       The actual nonunix_group and nonunix_gid syntax depends on the
       underlying group provider plugin (see the group__plugin description
       below).  For instance, the QAS AD plugin supports the following
       formats:

       +o   Group in the same domain: "Group Name"

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

       +o   Group SID: "S-1-2-34-5678901234-5678901234-5678901234-567"

       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.  If you do not
       specify a netmask along with the network number, 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, the corresponding
       netmask will be used.  The netmask may be specified either in standard
       IP address notation (e.g. 255.255.255.0 or ffff:ffff:ffff:ff:), 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 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.

        Cmnd_List ::= Cmnd |
                      Cmnd ',' Cmnd_List

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

        Cmnd ::= '!'* commandname |
                 '!'* directory |
                 '!'* "sudoedit" |
                 '!'* Cmnd_Alias

       A Cmnd_List is a list of one or more commandnames, directories, and
       other aliases.  A commandname is a fully qualified file name which may
       include shell-style wildcards (see the Wildcards section below).  A
       simple 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 subdirectories 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
       characters must be escaped with a '\' if they are used in command
       arguments: ',', ':', '=', '\'.  The special command "sudoedit" is used
       to permit a user to run sudo with the -e option (or as sudoedit).  It
       may take command line arguments just as a normal command does.

   Defaults
       Certain configuration options may be changed from their default values
       at runtime 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 backslash (\).

       Lists have two additional assignment operators, += and -=.  These
       operators 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 and
       user Defaults first, then runas Defaults and finally command defaults.

       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? SELinux_Spec? Tag_Spec* Cmnd

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

        SELinux_Spec ::= ('ROLE=role' | 'TYPE=type')

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

       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
       parentheses.  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 specified, 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 no Runas_Spec is
       specified the command 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
       setting the group to operator or system.

   SELinux_Spec
       On systems with SELinux support, sudoers entries may optionally have an
       SELinux role and/or type associated with a command.  If a role or type
       is specified with the command it will override any default values
       specified in sudoers.  A role or type specified on the command line,
       however, will supercede the values in sudoers.

   Tag_Spec
       A command may have zero or more tags associated with it.  There are
       eight possible tag values, NOPASSWD, PASSWD, NOEXEC, EXEC, SETENV,
       NOSETENV, LOG_INPUT, NOLOG_INPUT, LOG_OUTPUT and NOLOG_OUTPUT.  Once a
       tag is set on a Cmnd, subsequent Cmnds in the Cmnd_Spec_List, inherit
       the tag unless it is overridden by the opposite tag (i.e.: PASSWD
       overrides NOPASSWD and NOEXEC overrides EXEC).

       NOPASSWD and PASSWD

       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 overridden via the
       verifypw and listpw options.

       NOEXEC and EXEC

       If sudo has been compiled with noexec support and the underlying
       operating 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.

       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
       variables 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.

       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.

   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 POSIX glob(3) and
       fnmatch(3) routines.  Note that these are not regular expressions.

       *       Matches any set of zero or more characters.

       ?       Matches any single character.

       [...]   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 "}".

       POSIX character classes may also 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 path name.  When matching the command line arguments, however, a
       slash does get matched by wildcards.  This is to make a path like:

           /usr/bin/*

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

   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 entry it means that command is not allowed to be run
               with any arguments.

   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
       directives.

       This can be used, for example, to keep a site-wide sudoers file in
       addition to a local, per-machine file.  For the sake of this example
       the site-wide sudoers 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.  I.e., 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 sudo.d directory that
       the system package manager can drop sudoers rules into as part of
       package installation.  For example, given:

       #includedir /etc/sudoers.d

       sudo will 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 temporary/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.

       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.

   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
       preference 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 both
       in an alias and in front of a Cmnd.  This allows one to exclude certain
       values.  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.

       Whitespace between elements in a list as well as special syntactic
       characters 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
       earlier.  A list of all supported Defaults parameters, grouped by type,
       are listed below.

       Boolean Flags:

       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 HOME
                       is already set when the the env__reset option is
                       enabled, so always__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.

       authenticate    If set, users must authenticate themselves via a
                       password (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
                       overrides 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.

       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
                       security 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.  This flag is off by default.

       env_reset       If set, sudo will run the command in a minimal
                       environment containing the TERM, PATH, HOME, MAIL,
                       SHELL, LOGNAME, USER, USERNAME and SUDO_* variables.
                       Any variables in the caller's environment that match
                       the env_keep and env_check lists are then added,
                       followed by any variables present in the file specified
                       by the env__file option (if any).  The default contents
                       of the env_keep and env_check lists 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 (automounted).  The fast__glob
                       option causes sudo to use the fnmatch(3) function,
                       which does not access the file system to do its
                       matching.  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
                       trivially bypassed.  As such, this option should not be
                       used when sudoers 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.  I.e., instead of myhost you
                       would use myhost.mydomain.edu.  You may still use the
                       short form if you wish (and even mix the two).  Beware
                       that turning on fqdn requires sudo to make DNS lookups
                       which may make sudo unusable if DNS stops working (for
                       example if the machine is not plugged into the
                       network).  Also note that you must use the host's
                       official 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.  If your machine's host name (as
                       returned by the hostname command) is already fully
                       qualified you shouldn't need to set fqdn.  This flag is
                       off by default.

       ignore_dot      If set, sudo will ignore '.' or '' (current dir) in the
                       PATH environment variable; the PATH itself is not
                       modified.  This flag is off 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
                       operators 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.

       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-
                       syslog) 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
                       connected 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.

                       Input 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 normal sudo
                       log line, prefixed with TSID=.  The iolog__file option
                       may be used to control the format of the session ID.

                       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 is all that is required.

       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.  If the standard output or
                       standard error is not connected to the user's tty, due
                       to I/O redirection or because the command is part of a
                       pipeline, that output is also captured and stored in
                       separate log files.

                       Output 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 normal sudo
                       log line, prefixed with TSID=.  The iolog__file option
                       may be used to control the format of the session ID.

                       Output logs may be viewed with the sudoreplay(1m)
                       utility, which can also be used to list or search the
                       available logs.

       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_always     Send mail to the mailto user every time a users 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.  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.

       noexec          If set, all commands run via sudo will behave as if the
                       NOEXEC tag has been set, unless overridden by a EXEC
                       tag.  See the description of NOEXEC and EXEC below as
                       well as the "PREVENTING SHELL ESCAPES" section at the
                       end of this manual.  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
                       disadvantage 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 on by default.

       passprompt_override
                       The password prompt specified by passprompt will
                       normally 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.

       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
                       vector 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(1m) 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.
                       Disabling 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.  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.  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 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 if the env__reset option has not been
                       disabled, entries in the env__keep list will override
                       the value of set__logname.  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,
                       environment 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
                       potentially dangerous functionality when a program is
                       run setuid.  This option is only effective on systems
                       with either the setreuid() or setresuid() function.
                       This flag is off by default.

       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.  In addition, the
                       timestamp file name will include the target user's
                       name.  Note that this flag precludes the use of a uid
                       not listed in the passwd database 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 file named for
                       the tty the user is logged in on in the user's time
                       stamp directory.  If disabled, the time stamp of the
                       directory is used instead.  This flag is on by default.

       umask_override  If set, sudo will set the umask as specified by sudoers
                       without modification.  This makes it possible to
                       specify a more permissive umask in sudoers 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
                       available if sudo is configured with the
                       --with-logincap option.  This flag is off 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.

       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
                       visible on the screen.  This makes it possible to run
                       things like "rsh somehost sudo ls" since rsh(1) does
                       not allocate a tty.  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.

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

       Integers that can be used in aa 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
                       insufficient, 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
                       fractional 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 timestamp will never
                       expire.  This can be used to allow users to create or
                       delete their own timestamps 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
                       lowers 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 environment variable if
                       possible, or the first editor in the list that exists
                       and is executable.  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
                       supported:

                       %{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 command
                           will be run as (e.g. root)

                       %{runas_group}
                           expanded to the group name of the user the command
                           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
                       system's strftime() 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() function.

       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     This option is no longer supported.  The path to the
                       noexec file should now be set in the /etc/sudo.conf
                       file.

       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 command
                           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:.

       role            The default SELinux role to use when constructing a new
                       security context to run the command.  The default role
                       may be overridden on a per-command basis in sudoers or
                       via command line options.  This option is only
                       available whe sudo is built with SELinux support.

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

       syslog_badpri   Syslog priority to use when user authenticates
                       unsuccessfully.  Defaults to alert.

                       The following syslog priorities are supported: alert,
                       crit, debug, emerg, err, info, notice, and warning.

       syslog_goodpri  Syslog priority to use when user authenticates
                       successfully.  Defaults to notice.

                       See syslog_badpri for the list of supported syslog
                       priorities.

       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 timestamp files.
                       The default is /var/adm/sudo.

       timestampowner  The owner of the timestamp directory and the timestamps
                       stored therein.  The default is root.

       type            The default SELinux type to use when constructing a new
                       security context to run the command.  The default type
                       may be overridden on a per-command basis in sudoers or
                       via command line options.  This option is only
                       available whe sudo is built with SELinux support.

       Strings that can be used in aa 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 subject to other sudo
                   environment settings 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.

       group_plugin
                   A string containing a sudoers group plugin with optional
                   arguments.  This can be used to implement support for the
                   nonunix_group syntax described earlier.  The string should
                   consist of the plugin path, either fully-qualified or
                   relative to the /usr/local/libexec 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 example, given /etc/sudo-group, a group file in Unix
                   group format, the sample group plugin can be used:

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

                   For more information see sudo__plugin(4).

       lecture     This option controls when a short lecture will be printed
                   along with the password prompt.  It has the following
                   possible 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 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 -l
                           option.

                   any     At least one of the user's sudoers 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).
                   Setting 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 warning
                   and error mail.  The address should be enclosed in double
                   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.

       secure_path Path used for every command run from sudo.  If you don't
                   trust the people running sudo to have a sane PATH
                   environment 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 auth.

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

       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 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 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 aa boolean context:

       env_check       Environment variables to be removed from the user's
                       environment if the variable's value contains % or /
                       characters.  This can be used to guard against printf-
                       style format vulnerabilities in poorly-written
                       programs.  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 aforementioned check.  The default 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
                       default list of environment variables to remove is
                       displayed when sudo is run by root with the -V option.
                       Note that many operating systems will remove
                       potentially 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 default list of
                       variables to keep is displayed when sudo is run by root
                       with the -V option.

FILES
       /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/adm/sudo           Directory containing time stamps for the
                               sudoers security policy

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

EXAMPLES
       Below are example sudoers 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
        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).

        # 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/.

        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.  Note that this assumes passwd(1) does not take
       multiple user names on the command line.

        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.

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

       The user steve may run any command in the directory
       /usr/local/op_commands/ 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
       simply 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
       encapsulating in a shell script.

SECURITY NOTES
       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
       example:

           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
       reinforced by policy).

       Furthermore, 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 relative paths.  While this is typically only
       an inconvenience for rules that grant privileges, it can result in a
       security issue for rules that subtract or revoke privileges.

       For example, given the following sudoers 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 programs.  Note, however, that this applies only to
                 native dynamically-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
                 operating 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.

                 On Solaris 10 and higher, noexec uses Solaris privileges
                 instead of the LD_PRELOAD environment variable.

                 To enable noexec for a command, use the NOEXEC tag as
                 documented 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.

DEBUG FLAGS
       Versions 1.8.4 and higher of the sudoers plugin supports a debugging
       framework that can help track down what the plugin is doing internally
       if there is a problem.  This can be configured in the /etc/sudo.conf
       file as described in sudo(1m).

       The sudoers plugin uses the same debug flag format as sudo itself:
       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
       example, a priority of notice would include debug messages logged at
       notice and higher.

       The following subsystems are used by sudoers:

       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 Defaults settings

       env       environment handling

       ldap      LDAP-based sudoers

       logging   logging support

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

       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

       util      utility functions

SECURITY NOTES
       sudoers will check the ownership of its time stamp directory
       (/var/adm/sudo 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.  On
       systems that allow non-root users to give away files via chown(2), if
       the time stamp directory is located in a world-writable directory
       (e.g., /tmp), it is possible for a user to create the time stamp
       directory before sudo is run.  However, because sudoers checks the
       ownership and mode of the directory and its contents, the only damage
       that can be done is to "hide" files by putting them in the time stamp
       dir.  This is unlikely to happen since once the time stamp dir is owned
       by root and inaccessible by any other user, the user placing files
       there would be unable to get them back out.

       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
       sudo will log and complain.  This is done to keep a user from creating
       his/her own time stamp with a bogus date on systems that allow users to
       give away files if the time stamp directory is located in a world-
       writable directory.

       On systems where the boot time is available, sudoers will ignore time
       stamps that date from before the machine booted.

       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 time stamp file's
       modification time is within 5 minutes (or whatever the timeout is set
       to in sudoers).  When the tty__tickets option is enabled, the time stamp
       has per-tty granularity but still may outlive the user's session.  On
       Linux systems where the devpts filesystem is used, Solaris systems with
       the devices filesystem, as well as other systems that utilize a devfs
       filesystem that monotonically increase the inode number of devices as
       they are created (such as Mac OS X), sudoers is able to determine when
       a tty-based time stamp file is stale and will ignore it.
       Administrators should not rely on this feature as it is not universally
       available.

       If users have 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
       specification.

SEE ALSO
       rsh(1), su(1), fnmatch(3), glob(3), mktemp(3), strftime(3),
       sudoers.ldap(4), sudo__plugin(1m), sudo(1m), visudo(1m)

CAVEATS
       The sudoers file should always be edited by the visudo command which
       locks the file and does grammatical checking. It is imperative that
       sudoers be free of syntax errors since sudo will not run with a
       syntactically 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
       http://www.sudo.ws/sudo/bugs/

SUPPORT
       Limited free support is available via the sudo-users mailing list, see
       http://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or search
       the archives.

DISCLAIMER
       sudo is provided ``AS IS'' and any express or implied warranties,
       including, but not limited to, the implied warranties of
       merchantability and fitness for a particular purpose are disclaimed.
       See the LICENSE file distributed with sudo or
       http://www.sudo.ws/sudo/license.html for complete details.



1.8.4                          February  5, 2012                    SUDOERS(4)
