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sudoers

Name
     sudoers - default sudo security policy plugin

Description
     The sudoers policy plugin determines a user's sudo
     privileges.  It is the default sudo policy plugin.  The
     policy is driven by the /etc/sudoers file or, optionally in
     LDAP.  The policy format is described in detail in the
     SUDOERS FILE FORMAT section.  For information on storing
     sudoers policy information in LDAP, please see
     sudoers.ldap(4).

  Configuring sudo.conf for sudoers
     sudo consults the sudo.conf(4) file to determine which
     policy and and I/O logging plugins to load.  If no
     sudo.conf(4) file is present, or if it contains no Plugin
     lines, sudoers will be used for policy decisions and I/O
     logging.  To explicitly configure sudo.conf(4) to use the
     sudoers plugin, the following configuration can be used.

           Plugin sudoers_policy sudoers.so
           Plugin sudoers_io sudoers.so

     Starting with sudo 1.8.5, it is possible to specify optional
     arguments to the sudoers plugin in the sudo.conf(4) file.
     These arguments, if present, should be listed after the path
     to the plugin (i.e. after sudoers.so).  Multiple arguments
     may be specified, separated by white space.  For example:

           Plugin sudoers_policy sudoers.so sudoers_mode=0400

     The following plugin arguments are supported:

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

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

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

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

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

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

     For more information on configuring sudo.conf(4), please
     refer to its manual.

  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, the 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 new, minimal environment.  On
     AIX (and Linux systems without PAM), the environment is
     initialized with the contents of the /etc/environment file.
     The new environment contains 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 AIX (and
     Linux systems without PAM), the contents of /etc/environment
     are also included.  All other environment variables are
     removed.

     Finally, if the env_file option is defined, any variables
     present in that file will be set to their specified values
     as long as they would not conflict with an existing
     environment variable.

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

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

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

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

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

     Each production rule references others and thus makes up a
     grammar for the language.  EBNF also contains the following
     operators, which many readers will recognize from regular
     expressions.  Do not, however, 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.  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"

     See GROUP PROVIDER PLUGINS for more information.

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

     Runas_List ::= Runas_Member |
                    Runas_Member `,' Runas_List

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

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

     Host_List ::= Host |

                   Host `,' Host_List

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

     A Host_List is made up of one or more host names, IP
     addresses, network numbers, netgroups (prefixed with `+')
     and other aliases.  Again, the value of an item may be
     negated with the `!'  operator.  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:ffff::), or CIDR notation
     (number of bits, e.g. 24 or 64).  A host name may include
     shell-style wildcards (see the Wildcards section below), but
     unless the host name command on your machine returns the
     fully qualified host name, you'll need to use the fqdn
     option for wildcards to be useful.  Note that sudo only
     inspects actual network interfaces; this means that IP
     address 127.0.0.1 (localhost) will never match.  Also, the
     host name ``localhost'' will only match if that is the
     actual host name, which is usually only the case for non-
     networked systems.

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

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

     Cmnd_List ::= Cmnd |
                   Cmnd `,' Cmnd_List

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

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

     A Cmnd_List is a list of one or more command names,
     directories, and other aliases.  A command name is a fully
     qualified file name which may include shell-style wildcards
     (see the Wildcards section below).  A 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 sub-directories
     therein).

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

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

     For example, using openssl:

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

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

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

     Command digests are only supported by version 1.8.7 or
     higher.

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

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

     Default_Entry ::= Default_Type Parameter_List

     Parameter_List ::= Parameter |
                        Parameter `,' Parameter_List

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

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

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

     Solaris_Priv_Spec ::= ('PRIVS=privset' | `LIMITPRIVS=privset')

     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 both
     Runas_Lists are empty, the command may only be run as the
     invoking user.  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.  On
     Solaris systems, sudoers entries may optionally specify
     Solaris privilege set and/or limit privilege set associated
     with a command.  If privileges or limit privileges are
     specified with the command it will override any default
     values specified in sudoers.

     A privilege set is a comma-separated list of privilege
     names.  The ppriv(1) command can be used to list all
     privileges known to the system.  For example:

     $ ppriv -l

     In addition, there are several ``special'' privilege
     strings:

     none      the empty set

     all       the set of all privileges

     zone      the set of all privileges available in the current
               zone

     basic     the default set of privileges normal users are
               granted at login time

     Privileges can be excluded from a set by prefixing the
     privilege name with either an `!'  or `-' character.

  Tag_Spec
     A command may have zero or more tags associated with it.
     There are ten 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 (in other words,
     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 glob(3) and fnmatch(3) functions as specified
     by IEEE Std 1003.1 (POSIX.1).  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 `]'.

     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.  This is to make a path
     like:

         /usr/bin/*

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

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

     Wildcards in command line arguments should be used with
     care.  Because command line arguments are matched as a
     single, concatenated string, a wildcard such as `?'  or `*'
     can match multiple words.  For example, while a sudoers
     entry like:

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

     will allow command like:

         $ sudo cat /var/log/messages.1

     It will also allow:

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

     which is probably not what was intended.

  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.

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

  Including other files from within sudoers
     It is possible to include other sudoers files from within
     the sudoers file currently being parsed using the #include
     and #includedir 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.  In other words, if the
     machine's host name is ``xerxes'', then

         #include /etc/sudoers.%h

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

     The #includedir directive can be used to create a 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 in a list or alias as well as in front of a Cmnd.
     This allows one to exclude certain values.  For the `!'
     operator to be effective, there must be something for it to
     exclude.  For example, to match all users except for root
     one would use:

         ALL,!root

     If the ALL, is omitted, as in:

         !root

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

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

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

     White space between elements in a list as well as special
     syntactic 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 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.

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

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

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

     env_editor        If set, visudo will use the value of the

                       EDITOR or VISUAL environment variables
                       before falling back on the default editor
                       list.  Note that this may create a
                       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 (auto mounted).  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 or 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
                       when the local host name (as returned by
                       the hostname command) does not contain the
                       domain name.  In other words, instead of
                       myhost you would use myhost.mydomain.edu.
                       You may still use the short form if you
                       wish (and even mix the two).  This option
                       is only effective when the ``canonical''
                       host name, as returned by the
                       getaddrinfo() or gethostbyname() function,
                       is a fully-qualified domain name.  This is
                       usually the case when the system is
                       configured to use DNS for host name
                       resolution.

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

           192.168.1.1    xyzzy.sudo.ws xyzzy

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

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

     This flag is off by default.

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

     ignore_local_sudoers
                       If set via LDAP, parsing of /etc/sudoers
                       will be skipped.  This is intended for
                       Enterprises that wish to prevent the usage
                       of local sudoers files so that only LDAP
                       is used.  This thwarts the efforts of
                       rogue 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.  If the command the user is
                       attempting to run is not permitted by
                       sudoers and one of the mail_always,
                       mail_no_host, mail_no_perms or
                       mail_no_user flags are set, this flag will
                       have no effect.  This flag is off by
                       default.

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

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

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

     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.

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

                       This setting is only supported by version
                       1.8.7 or higher.

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

                       This setting is only supported by version
                       1.8.8 or higher.

     passprompt_override
                       The password prompt specified by
                       passprompt will 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.

     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.

     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 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 that support either the
                       setreuid(2) or setresuid(2) system call.
                       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
                       time stamp 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_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 ``ssh somehost
                       sudo ls'' since by default, ssh(1) does
                       not allocate a tty when running a command.
                       This flag is off by default.

     Integers:

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

     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).

     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 time
                       stamp will never expire.  This can be used
                       to allow users to create or delete their
                       own time stamps via ``sudo -v'' and ``sudo
                       -k'' respectively.

     umask             Umask to use when running the command.
                       Negate this option or set it to 0777 to
                       preserve the user's umask.  The actual
                       umask that is used will be the union of
                       the user's umask and the value of the
                       umask option, which defaults to 0022.
                       This guarantees that sudo never 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 /usr/bin/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(3)
                       function will be expanded.

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

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

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

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

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

     limitprivs        The default Solaris limit privileges to
                       use when constructing a new privilege set
                       for a command.  This bounds all privileges
                       of the executing process.  The default
                       limit privileges may be overridden on a
                       per-command basis in sudoers.  This option
                       is only available if sudoers is built on
                       Solaris 10 or higher.

     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 ***''.

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

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

                       This setting is only supported by version
                       1.8.7 or higher.

     noexec_file       As of sudo version 1.8.1 this option is no
                       longer supported.  The path to the noexec
                       file should now be set in the sudo.conf(4)
                       file.

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

                       This setting is only supported by version
                       1.8.8 or higher.

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

                       This setting is only supported by version
                       1.8.8 or higher.

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

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

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

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

                       %U    expanded to the login name of the
                             user the 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:''.

     privs             The default Solaris privileges to use when
                       constructing a new privilege set for a
                       command.  This is passed to the executing
                       process via the inherited privilege set,
                       but is bounded by the limit privileges.
                       If the privs option is specified but the
                       limitprivs option is not, the limit
                       privileges of the executing process is set
                       to privs.  The default privileges may be
                       overridden on a per-command basis in
                       sudoers.  This option is only available if
                       sudoers is built on Solaris 10 or higher.

     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
                       time stamp files.  The default is
                       /system/volatile/sudo.

     timestampowner    The owner of the time stamp directory and
                       the time stamps stored therein.  The
                       default is root.

     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.

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

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

     The following group provider plugins are installed by
     default:

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

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

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

               Defaults group_plugin=system_group.so

     The group provider plugin API is described in detail in
     sudo_plugin(1m).

Log Format
     sudoers can log events using either syslog(3) or a simple
     log file.  In each case the log format is almost identical.

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

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

     Where the fields are as follows:

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

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

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

     username      The login name of the user who ran sudo.

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

     cwd           The current working directory that sudo was
                   run in.

     runasuser     The user the command was run as.

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

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

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

     command       The actual command that was executed.

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

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

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

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

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

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

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

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

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

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

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

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

     unable to open/read /etc/sudoers
        The sudoers file could not be opened for reading.  This
        can happen when the sudoers file is located on a remote
        file system that maps user ID 0 to a different value.
        Normally, sudoers tries to open sudoers using group
        permissions to avoid this problem.  Consider either
        changing the ownership of /etc/sudoers or adding an
        argument like ``sudoers_uid=N'' (where `N' is the user ID
        that owns the sudoers file) to the end of the sudoers
        Plugin line in the sudo.conf(4) file.

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

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

     /etc/sudoers is owned by uid N, should be 0
        The sudoers file has the wrong owner.  If you wish to
        change the sudoers file owner, please add
        ``sudoers_uid=N'' (where `N' is the user ID that owns the
        sudoers file) to the sudoers Plugin line in the
        sudo.conf(4) file.

     /etc/sudoers is world writable
        The permissions on the sudoers file allow all users to
        write to it.  The sudoers file must not be world-
        writable, the default file mode is 0440 (readable by
        owner and group, writable by none).  The default mode may
        be changed via the ``sudoers_mode'' option to the sudoers
        Plugin line in the sudo.conf(4) file.

     /etc/sudoers is owned by gid N, should be 1
        The sudoers file has the wrong group ownership.  If you
        wish to change the sudoers file group ownership, please
        add ``sudoers_gid=N'' (where `N' is the group ID that
        owns the sudoers file) to the sudoers Plugin line in the
        sudo.conf(4) file.

     unable to open /system/volatile/sudo/username/ttyname
        sudoers was unable to read or create the user's time
        stamp file.

     unable to write to /system/volatile/sudo/username/ttyname
        sudoers was unable to write to the user's time stamp
        file.

     unable to mkdir to /system/volatile/sudo/username
        sudoers was unable to create the user's time stamp
        directory.

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

     On most systems, syslog(3) has a relatively small log
     buffer.  To prevent the command line arguments from being
     truncated, sudoers will split up log messages that are
     larger than 960 characters (not including the date,
     hostname, and the string ``sudo'').  When a message is
     split, additional parts will include the string ``(command
     continued)'' after the user name and before the continued
     command line arguments.

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

     1.   The progname and hostname fields are not present.

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

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

Files
     /etc/sudo.conf            Sudo front end configuration

     /etc/sudoers              List of who can run what

     /etc/group                Local groups file

     /etc/netgroup             List of network groups

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

     /system/volatile/sudo     Directory containing time stamps
                               for the sudoers security policy

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

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

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

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

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

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

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

     FULLTIMERS     ALL = NOPASSWD: ALL

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

     PARTTIMERS     ALL = ALL

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

     jack      CSNETS = ALL

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

     lisa      CUNETS = ALL

     The user lisa may run any command on any host in the CUNETS
     alias (the class B network 128.138.0.0).
     operator  ALL = DUMPS, KILL, SHUTDOWN, HALT, REBOOT, PRINTING,\
               sudoedit /etc/printcap, /usr/oper/bin/

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

     joe       ALL = /usr/bin/su operator

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

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

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

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

     The user pete is allowed to change anyone's password except
     for root on the HPPA machines.  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.  While
     not specifically mentioned in the rule, the commands in the
     PAGERS Cmnd_Alias all reside in /usr/bin and have the noexec
     option set.

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

     The user steve may run any command in the directory
     /usr/local/op_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
  Limitations of the `!' operator
     It is generally not effective to ``subtract'' commands from
     ALL using the `!' operator.  A user can trivially circumvent
     this by copying the desired command to a different name and
     then executing that.  For 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).

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

  Security implications of fast_glob
     If the fast_glob option is in use, it is not possible to
     reliably negate commands where the path name includes
     globbing (aka wildcard) characters.  This is because the C
     library's fnmatch(3) function cannot resolve 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 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 (see
     below).

  Secure editing
     The sudoers plugin includes sudoedit support which allows
     users to securely edit files with the editor of their
     choice.  As sudoedit is a built-in command, it must be
     specified in sudoers without a leading path.  However, it
     may take command line arguments just as a normal command
     does.  For example, to allow user operator to edit the
     ``message of the day'' file:

           operator  sudoedit /etc/motd

     The operator user then runs sudoedit as follows:

           $ sudoedit /etc/motd

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

  Time stamp file checks
     sudoers will check the ownership of its time stamp directory
     (/system/volatile/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.

Debugging
     Versions 1.8.4 and higher of the sudoers plugin support a
     flexible debugging framework that can help track down what
     the plugin is doing internally if there is a problem.  This
     can be configured in the sudo.conf(4) file.

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

     The priorities used by sudoers, in order of decreasing
     severity, are:  crit, err, warn, notice, diag, info, trace
     and debug.  Each priority, when specified, also includes all
     priorities higher than it.  For example, a priority of
     notice would include debug messages logged at notice and
     higher.

     The following subsystems are used by the sudoers plugin:

     alias     User_Alias, Runas_Alias, Host_Alias and Cmnd_Alias
               processing

     all       matches every subsystem

     audit     BSM and Linux audit code

     auth      user authentication

     defaults  sudoers 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

     sssd      SSSD-based sudoers

     util      utility functions
     For example:

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

     For more information, see the sudo.conf(4) manual.

Attributes
     See attributes(5) for descriptions of the following
     attributes:

     box; cbp-1 | cbp-1 l | l .  ATTRIBUTE TYPE ATTRIBUTE VALUE =
     Availability   security/sudo = Stability Uncommitted

See Also
     ssh(1), su(1), fnmatch(3), glob(3), mktemp(3), strftime(3),
     sudo.conf(4), 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.

Notes
     This software was built from source available at
     https://java.net/projects/solaris-userland.  The original
     community source was downloaded from
     http://www.sudo.ws/sudo/dist/sudo-1.8.9p5.tar.gz

     Further information about this software can be found on the
     open source community website at http://www.sudo.ws/.
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