


SUDOERS(5)             MAINTENANCE COMMANDS            SUDOERS(5)


NAME
       sudoers - list of which users may execute what

DESCRIPTION
       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 conflicting values, 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 produc-
       tion 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 follow-
       ing operators, which many readers will recognize from reg-
       ular expressions.  Do not, however, confuse them with
       "wildcard" characters, which have different meanings.

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

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

       +       Means that the preceding symbol (or group of sym-
               bols) 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.






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        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 upper-
       case 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 ::= '!'* username |
                 '!'* '%'group |
                 '!'* '+'netgroup |
                 '!'* User_Alias

       A User_List is made up of one or more usernames, system
       groups (prefixed with '%'), netgroups (prefixed with '+')
       and other aliases.  Each list item may be prefixed with
       one or more '!' operators.  An odd number of '!' operators
       negate the value of the item; an even number just cancel
       each other out.

        Runas_List ::= Runas_User |
                       Runas_User ',' Runas_List

        Runas_User ::= '!'* username |
                       '!'* '#'uid |
                       '!'* '%'group |
                       '!'* +netgroup |
                       '!'* Runas_Alias



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       A Runas_List is similar to a User_List except that it can
       also contain uids (prefixed with '#') and instead of
       User_Aliases it can contain Runas_Aliases.  Note that
       usernames and groups are matched as strings.  In other
       words, two users (groups) with the same uid (gid) are con-
       sidered 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 ::= '!'* hostname |
                 '!'* ip_addr |
                 '!'* network(/netmask)? |
                 '!'* '+'netgroup |
                 '!'* Host_Alias

       A Host_List is made up of one or more hostnames, 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 with a network number, the netmask of the host's
       ethernet interface(s) will be used when matching.  The
       netmask may be specified either in dotted quad notation
       (e.g.  255.255.255.0) or CIDR notation (number of bits,
       e.g. 24).  A hostname may include shell-style wildcards
       (see the Wildcards section below), but unless the hostname
       command on your machine returns the fully qualified host-
       name, you'll need to use the fqdn option for wildcards to
       be useful.

        Cmnd_List ::= Cmnd |
                      Cmnd ',' Cmnd_List

        commandname ::= filename |
                        filename args |
                        filename '""'

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

       A Cmnd_List is a list of one or more commandnames, direc-
       tories, and other aliases.  A commandname is a fully qual-
       ified filename which may include shell-style wildcards
       (see the Wildcards section below).  A simple filename
       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 pathname ending in a '/'.  When you specify a



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       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 argu-
       ments: ',', ':', '=', '\'.  The special command "sudoedit"
       is used to permit a user to run sudo with the -e flag (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, or commands being run
       as a specific user.

        Default_Type ::= 'Defaults' |
                         'Defaults' '@' Host |
                         'Defaults' ':' User |
                         'Defaults' '>' RunasUser

        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 dis-
       able 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.

       Flags:

       long_otp_prompt
                   When validating with a One Time Password



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                   scheme (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.

       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.  Currently, while it is possible
                   to set ignore_dot in sudoers, its value is not
                   used.  This option should be considered read-
                   only (it will be fixed in a future version of
                   sudo).

       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 run-
                   ning sudo does not enter the correct password.
                   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.

       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.

       tty_tickets If set, users must authenticate on a per-tty
                   basis.  Normally, sudo uses a directory in the
                   ticket dir with the same name as the user run-
                   ning it.  With this flag enabled, sudo will
                   use a file named for the tty the user is
                   logged in on in that directory.  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



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                   may be overridden via the PASSWD and NOPASSWD
                   tags.  This flag is on by default.

       root_sudo   If set, root is allowed to run sudo too.  Dis-
                   abling 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 and from running sudoedit.  Dis-
                   abling root_sudo provides no real additional
                   security; it exists purely for historical rea-
                   sons.  This flag is on by default.

       log_host    If set, the hostname will be logged in the
                   (non-syslog) sudo log file.  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.

       shell_noargs
                   If set and sudo is invoked with no arguments
                   it acts as if the -s flag 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.

       set_home    If set and sudo is invoked with the -s flag
                   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 flag imply -H.  This
                   flag is off by default.

       always_set_home
                   If set, 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
                   flag is always implied.  This flag is off by
                   default.

       path_info   Normally, sudo will tell the user when a com-
                   mand could not be found in their PATH environ-
                   ment 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



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                   be confusing.  This flag is off by default.

       preserve_groups
                   By default sudo will initialize the group vec-
                   tor 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.

       fqdn        Set this flag if you want to put fully quali-
                   fied hostnames in the sudoers file.  I.e.,
                   instead of myhost you would use myhost.mydo-
                   main.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 hostname
                   (as returned by the hostname command) is
                   already fully qualified you shouldn't need to
                   set fqdn.  This flag is off by default.

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

       requiretty  If set, sudo will only run when the user is
                   logged in to a real tty.  This will disallow
                   things like "rsh somehost sudo ls" since
                   rsh(1) does not allocate a tty.  Because it is
                   not possible to turn off echo when there is no
                   tty present, some sites may wish to set this
                   flag to prevent a user from entering a visible
                   password.  This flag is off by default.

       env_editor  If set, visudo will use the value of the EDI-
                   TOR 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 on by
                   default.




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       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.

       targetpw    If set, sudo will prompt for the password of
                   the user specified by the -u flag (defaults to
                   root) instead of the password of the invoking
                   user.  Note that this precludes the use of a
                   uid not listed in the passwd database as an
                   argument to the -u flag.  This flag is off by
                   default.

       set_logname Normally, sudo will set the LOGNAME and USER
                   environment variables to the name of the tar-
                   get user (usually root unless the -u flag is
                   given).  However, since some programs (includ-
                   ing the RCS revision control system) use LOG-
                   NAME 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.

       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.  Note, however, that
                   this means that sudo will run with the real
                   uid of the invoking user which may allow that
                   user to kill sudo before it can log a failure,
                   depending on how your OS defines the interac-
                   tion between signals and setuid processes.

       env_reset   If set, sudo will reset the environment to
                   only contain the following variables: HOME,
                   LOGNAME, PATH, SHELL, TERM, and USER (in addi-
                   tion to the SUDO_* variables).  Of these, only
                   TERM is copied unaltered from the old environ-
                   ment.  The other variables are set to default
                   values (possibly modified by the value of the
                   set_logname option).  If sudo was compiled
                   with the SECURE_PATH option, its value will be
                   used for the PATH environment variable.  Other
                   variables may be preserved with the env_keep



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                   option.

       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.

       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 "PRE-
                   VENTING SHELL ESCAPES" section at the end of
                   this manual.  This flag is off by default.

       ignore_local_sudoers
                   If set via LDAP, parsing of @sysconfdir@/sudo-
                   ers will be skipped.  This is intended for an
                   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
                   @sysconfdir@/sudoers.  When this option is
                   present, @sysconfdir@/sudoers does not even
                   need to exist.  Since this options 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.

       Integers:

       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 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).

       timestamp_timeout
                   Number of minutes that can elapse before sudo
                   will ask for a passwd again.  The default is
                   5.  Set this to 0 to always prompt for a pass-
                   word.  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



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                   their own timestamps via sudo -v and sudo -k
                   respectively.

       passwd_timeout
                   Number of minutes before the sudo password
                   prompt times out.  The default is 5, set this
                   to 0 for no password timeout.

       umask       Umask to use when running the command.  Negate
                   this option or set it to 0777 to preserve the
                   user's umask.  The default is 0022.

       Strings:

       mailsub     Subject of the mail sent to the mailto user.
                   The escape %h will expand to the hostname of
                   the machine.  Default is *** SECURITY informa-
                   tion for %h ***.

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

       timestampdir
                   The directory in which sudo stores its times-
                   tamp files.  The default is /var/run/sudo.

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

       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 (`%') escapes are supported:

                   %u      expanded to the invoking user's login
                           name

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

                   %h      expanded to the local hostname without
                           the domain name

                   %H      expanded to the local hostname includ-
                           ing the domain name (on if the
                           machine's hostname is fully qualified
                           or the fqdn option is set)

                   %%      two consecutive % characters are



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                           collaped into a single % character

                   The default value is Password:.

       runas_default
                   The default user to run commands as if the -u
                   flag is not specified on the command line.
                   This defaults to root.  Note that if
                   runas_default is set it must occur before any
                   Runas_Alias specifications.

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

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

       editor      A colon (':') separated list of editors
                   allowed to be used with visudo.  visudo will
                   choose the editor that matches the user's USER
                   environment variable if possible, or the first
                   editor in the list that exists and is exe-
                   cutable.  The default is the path to vi on
                   your system.

       noexec_file Path to a shared library containing dummy ver-
                   sions of the execv(), execve() and fexecve()
                   library functions that just return an error.
                   This is used to implement the noexec function-
                   ality on systems that support LD_PRELOAD or
                   its equivalent.  Defaults to
                   /usr/libexec/sudo_noexec.so.

       Strings that can be used in a boolean context:

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

                   never   Never lecture the user.

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

                   always  Always lecture the user.

                   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.





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       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.

       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.

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

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

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

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

       exempt_group
                   Users in this group are exempt from password
                   and PATH requirements.  This is not set by
                   default.

       verifypw    This option controls when a password will be
                   required when a user runs sudo with the -v
                   flag.  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.

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

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

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

                   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.




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       listpw      This option controls when a password will be
                   required when a user runs sudo with the -l
                   flag.  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.

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

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

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

                   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.

       Lists that can be used in a 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 vulnera-
                   bilities in poorly-written programs.  The
                   argument may be a double-quoted, space-sepa-
                   rated list or a single value without dou-
                   ble-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 check
                   is printed when sudo is run by root with the
                   -V option.

       env_delete  Environment variables to be removed from the
                   user's environment.  The argument may be a
                   double-quoted, space-separated list or a sin-
                   gle value without double-quotes.  The list can
                   be replaced, added to, deleted from, or dis-
                   abled by using the =, +=, -=, and ! operators
                   respectively.  The default list of environment
                   variables to remove is printed 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



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                   user's environment when the env_reset option
                   is in effect.  This allows fine-grained con-
                   trol over the environment sudo-spawned pro-
                   cesses will receive.  The argument may be a
                   double-quoted, space-separated list or a sin-
                   gle value without double-quotes.  The list can
                   be replaced, added to, deleted from, or dis-
                   abled by using the =, +=, -=, and ! operators
                   respectively.  This list has no default mem-
                   bers.

       When logging via syslog(3), sudo accepts the following
       values for the syslog facility (the value of the syslog
       Parameter): authpriv (if your OS supports it), auth, dae-
       mon, user, local0, local1, local2, local3, local4, local5,
       local6, and local7.  The following syslog priorities are
       supported: alert, crit, debug, emerg, err, info, notice,
       and warning.

       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? Tag_Spec* Cmnd

        Runas_Spec ::= '(' Runas_List ')'

        Tag_Spec ::= ('NOPASSWD:' | 'PASSWD:' | 'NOEXEC:' | 'EXEC:')

       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.

       Let's break that down into its constituent parts:

       Runas_Spec

       A Runas_Spec is simply a Runas_List (as defined above)
       enclosed in a set of parentheses.  If you do not specify a
       Runas_Spec in the user specification, a default Runas_Spec
       of root will be used.  A Runas_Spec sets the default for
       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.,




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        $ 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.

       Tag_Spec

       A command may have zero or more tags associated with it.
       There are four possible tag values, NOPASSWD, PASSWD,
       NOEXEC, EXEC.  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 (ie: PASSWD overrides
       NOPASSWD and EXEC overrides NOEXEC).

       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 as root
       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 per-
       tain 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 support it, the NOEXEC tag can
       be used to prevent a dynamically-linked executable from



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       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.

       Wildcards

       sudo allows shell-style wildcards (aka meta or glob char-
       acters) to be used in pathnames as well as command line
       arguments in the sudoers file.  Wildcard matching is done
       via the POSIX fnmatch(3) routine.  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 "}".

       Note that a forward slash ('/') will not be matched by
       wildcards used in the pathname.  When matching the command
       line arguments, however, a slash does get matched by wild-
       cards.  This is to make a path like:

           /usr/bin/*

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

       WARNING: a pathname with wildcards will not match a user
       command that consists of a relative path.  In other words,
       given the following sudoers entry:

           billy  workstation = /usr/bin/*

       user billy will be able to run any command in /usr/bin as
       root, such as /usr/bin/w.  The following two command will
       be allowed (the first assumes that /usr/bin is in the
       user's path):

           $ sudo w
           $ sudo /usr/bin/w




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       However, this will not:

           $ cd /usr/bin
           $ sudo ./w

       For this reason you should only grant access to commands
       using wildcards and never restrict access using them.
       This limitation will be removed in a future version of
       sudo.

       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 com-
               mand is not allowed to be run with any arguments.

       Other special characters and reserved words

       The pound sign ('#') is used to indicate a comment (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 username or
       hostname): '@', '!', '=', ':', ',', '(', ')', '\'.





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FILES
        /etc/sudoers           List of who can run what
        /etc/group             Local groups file
        /etc/netgroup          List of network groups

EXAMPLES
       Since the sudoers file is parsed in a single pass, order
       is important.  In general, you should structure sudoers
       such that the Host_Alias, User_Alias, and Cmnd_Alias spec-
       ifications come first, followed by any Default_Entry
       lines, and finally the Runas_Alias and user specifica-
       tions.  The basic rule of thumb is you cannot reference an
       Alias that has not already been defined.

       Below are example sudoers entries.  Admittedly, some of
       these are a bit contrived.  First, we define our aliases:

        # 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

        # 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

       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 or USER



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SUDOERS(5)             MAINTENANCE COMMANDS            SUDOERS(5)


       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.

        # 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

       The User specification is the part that actually deter-
       mines 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 them-
       selves 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 main-
       tenance.  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/.



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SUDOERS(5)             MAINTENANCE COMMANDS            SUDOERS(5)


        joe            ALL = /usr/bin/su operator

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

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

       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 usernames 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 give su(1) any flags.

        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



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SUDOERS(5)             MAINTENANCE COMMANDS            SUDOERS(5)


       /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 circum-
       vent 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 com-
       mands 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).

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 restrictions.  Common programs that permit shell
       escapes include shells (obviously), editors, paginators,
       mail and terminal programs.

       Many systems that support shared libraries have the abil-
       ity to override default library functions by pointing an
       environment variable (usually LD_PRELOAD) to an alternate
       shared library.  On such systems, sudo's noexec function-
       ality 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



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       running under binary emulation are not affected.

       To tell whether or not sudo supports noexec, you can run
       the following as root:

           sudo -V | grep "dummy exec"

       If the resulting output contains a line that begins with:

           File containing dummy exec functions:

       then sudo may be able to replace the exec family of func-
       tions in the standard library with its own that simply
       return an error.  Unfortunately, there is no foolproof way
       to know whether or not noexec will work at compile-time.
       Noexec should work on SunOS, Solaris, *BSD, Linux, IRIX,
       Tru64 UNIX, MacOS X, and HP-UX 11.x.  It is known not to
       work on AIX and UnixWare.  Noexec is expected to work on
       most operating systems that support the LD_PRELOAD envi-
       ronment 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 sup-
       ported.

       To enable noexec for a command, use the NOEXEC tag as doc-
       umented 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 see if it works.

       Note that disabling shell escapes is not a panacea.  Pro-
       grams running as root are still capable of many poten-
       tially hazardous operations (such as changing or overwrit-
       ing files) that could lead to unintended privilege escala-
       tion.  In the specific case of an editor, a safer approach
       is to give the user permission to run sudoedit.

SEE ALSO
       rsh(1), su(1), fnmatch(3), sudo(8), visudo(8)

CAVEATS
       The sudoers file should always be edited by the visudo
       command which locks the file and does grammatical check-
       ing. It is imperative that sudoers be free of syntax
       errors since sudo will not run with a syntactically incor-
       rect sudoers file.




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       When using netgroups of machines (as opposed to users), if
       you store fully qualified hostnames in the netgroup (as is
       usually the case), you either need to have the machine's
       hostname 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
       Commercial support is available for sudo, see
       http://www.sudo.ws/sudo/support.html for details.

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

DISCLAIMER
       Sudo is provided ``AS IS'' and any express or implied war-
       ranties, including, but not limited to, the implied war-
       ranties 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 com-
       plete details.































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