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    Command:

    sudoers

    
         default sudo policy plugin.  The policy is driven by the /etc/sudoers
         file or, optionally in LDAP.  The policy format is described in detail in
         the SUDOERS FILE FORMAT section.  For information on storing sudoers pol-
         icy information in LDAP, please see sudoers.ldap(5).
    
       Authentication and logging
         The sudoers security policy requires that most users authenticate them-
         selves before they can use sudo.  A password is not required if the
         invoking user is root, if the target user is the same as the invoking
         user, or if the policy has disabled authentication for the user or com-
         mand.  Unlike su(1), when sudoers requires authentication, it validates
         the invoking user's credentials, not the target user's (or root's) cre-
         dentials.  This can be changed via the rootpw, targetpw and runaspw
         flags, described later.
    
         If a user who is not listed in the policy tries to run a command via
         sudo, mail is sent to the proper authorities.  The address used for such
         mail is configurable via the mailto Defaults entry (described later) and
         defaults to root.
    
         Note that 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 pro-
         itly denied by the env_check and env_delete options are inherited from
         the invoking process.  In this case, env_check and env_delete behave like
         a blacklist.  Since it is not possible to blacklist all potentially dan-
         gerous 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 out-
         put of "sudo -V" when run as root.
    
         Note that the dynamic linker on most operating systems will remove vari-
         ables that can control dynamic linking from the environment of setuid
         executables, including sudo.  Depending on the operating system this may
         include _RLD*, DYLD_*, LD_*, LDR_*, LIBPATH, SHLIB_PATH, and others.
         These type of variables are removed from the environment before sudo even
         begins execution and, as such, it is not possible for sudo to preserve
         them.
    
         As a special case, if sudo's -i option (initial login) is specified,
         sudoers will initialize the environment regardless of the value of
         env_reset.  The DISPLAY, PATH and TERM variables remain unchanged; HOME,
         MAIL, SHELL, USER, and LOGNAME are set based on the target user.  On AIX
         (and Linux systems without PAM), the contents of /etc/environment are
         also included.  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 con-
         flict with an existing environment variable.
    
    
    

    SUDOERS FILE FORMAT

         The sudoers file is composed of two types of entries: aliases (basically
         variables) and user specifications (which specify who may run what).
    
         When multiple entries match for a user, they are applied in order.  Where
         there are multiple matches, the last match is used (which is not neces-
         sarily the most specific match).
    
         The sudoers grammar will be described below in Extended Backus-Naur Form
         (EBNF).  Don't despair if you are unfamiliar with EBNF; it is fairly sim-
         ple, and the definitions below are annotated.
    
       Quick guide to EBNF
         EBNF is a concise and exact way of describing the grammar of a language.
         Each EBNF definition is made up of production rules.  E.g.,
    
         symbol ::= definition | alternate1 | alternate2 ...
    
         Each production rule references others and thus makes up a grammar for
         the language.  EBNF also contains the following operators, which many
         readers will recognize from regular expressions.  Do not, however, con-
         fuse them with "wildcard" characters, which have different meanings.
    
       Aliases
         There are four kinds of aliases: User_Alias, Runas_Alias, Host_Alias and
         Cmnd_Alias.
    
         Alias ::= 'User_Alias'  User_Alias (':' User_Alias)* |
                   'Runas_Alias' Runas_Alias (':' Runas_Alias)* |
                   'Host_Alias'  Host_Alias (':' Host_Alias)* |
                   'Cmnd_Alias'  Cmnd_Alias (':' Cmnd_Alias)*
    
         User_Alias ::= NAME '=' User_List
    
         Runas_Alias ::= NAME '=' Runas_List
    
         Host_Alias ::= NAME '=' Host_List
    
         Cmnd_Alias ::= NAME '=' Cmnd_List
    
         NAME ::= [A-Z]([A-Z][0-9]_)*
    
         Each alias definition is of the form
    
         Alias_Type NAME = item1, item2, ...
    
         where Alias_Type is one of User_Alias, Runas_Alias, Host_Alias, or
         Cmnd_Alias.  A NAME is a string of uppercase letters, numbers, and under-
         score characters ('_').  A NAME must start with an uppercase letter.  It
         is possible to put several alias definitions of the same type on a single
         line, joined by a colon (':').  E.g.,
    
         Alias_Type NAME = item1, item2, item3 : NAME = item4, item5
    
         The definitions of what constitutes a valid alias member follow.
    
         User_List ::= User |
                       User ',' User_List
    
         User ::= '!'* user name |
                  '!'* #uid |
                  '!'* %group |
                  '!'* %#gid |
                  '!'* +netgroup |
                  '!'* %:nonunix_group |
                  '!'* %:#nonunix_gid |
                  '!'* User_Alias
    
         A User_List is made up of one or more user names, user ids (prefixed with
         '#'), system group names and ids (prefixed with '%' and '%#' respec-
         tively), netgroups (prefixed with '+'), non-Unix group names and IDs
         (prefixed with '%:' and '%:#' respectively) and User_Aliases. Each list
         item may be prefixed with zero or more '!' operators.  An odd number of
         '!' operators negate the value of the item; an even number just cancel
         each other out.
    
         ?     Group SID: "%:S-1-2-34-5678901234-5678901234-5678901234-567"
    
         Note that quotes around group names are optional.  Unquoted strings must
         use a backslash ('\') to escape spaces and special characters.  See Other
         special characters and reserved words for a list of characters that need
         to be escaped.
    
         Runas_List ::= Runas_Member |
                        Runas_Member ',' Runas_List
    
         Runas_Member ::= '!'* user name |
                          '!'* #uid |
                          '!'* %group |
                          '!'* %#gid |
                          '!'* %:nonunix_group |
                          '!'* %:#nonunix_gid |
                          '!'* +netgroup |
                          '!'* Runas_Alias
    
         A Runas_List is similar to a User_List except that instead of
         User_Aliases it can contain Runas_Aliases.  Note that user names and
         groups are matched as strings.  In other words, two users (groups) with
         the same uid (gid) are considered to be distinct.  If you wish to match
         all user names with the same uid (e.g. root and toor), you can use a uid
         instead (#0 in the example given).
    
         Host_List ::= Host |
                       Host ',' Host_List
    
         Host ::= '!'* host name |
                  '!'* ip_addr |
                  '!'* network(/netmask)? |
                  '!'* +netgroup |
                  '!'* Host_Alias
    
         A Host_List is made up of one or more host names, IP addresses, network
         numbers, netgroups (prefixed with '+') and other aliases.  Again, the
         value of an item may be negated with the '!' operator.  If you do not
         specify a netmask along with the network number, sudo will query each of
         the local host's network interfaces and, if the network number corre-
         sponds to one of the hosts's network interfaces, the corresponding net-
         mask 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.
         other aliases.  A command name is a fully qualified file name which may
         include shell-style wildcards (see the Wildcards section below).  A sim-
         ple file name allows the user to run the command with any arguments
         he/she wishes.  However, you may also specify command line arguments
         (including wildcards).  Alternately, you can specify "" to indicate that
         the command may only be run without command line arguments.  A directory
         is a fully qualified path name ending in a '/'.  When you specify a
         directory in a Cmnd_List, the user will be able to run any file within
         that directory (but not in any sub-directories therein).
    
         If a Cmnd has associated command line arguments, then the arguments in
         the Cmnd must match exactly those given by the user on the command line
         (or match the wildcards if there are any).  Note that the following char-
         acters must be escaped with a '\' if they are used in command arguments:
         ',', ':', '=', '\'.  The special command "sudoedit" is used to permit a
         user to run sudo with the -e option (or as sudoedit).  It may take com-
         mand line arguments just as a normal command does.
    
       Defaults
         Certain configuration options may be changed from their default values at
         run-time via one or more Default_Entry lines.  These may affect all users
         on any host, all users on a specific host, a specific user, a specific
         command, or commands being run as a specific user.  Note that per-command
         entries may not include command line arguments.  If you need to specify
         arguments, define a Cmnd_Alias and reference that instead.
    
         Default_Type ::= 'Defaults' |
                          'Defaults' '@' Host_List |
                          'Defaults' ':' User_List |
                          'Defaults' '!' Cmnd_List |
                          'Defaults' '>' Runas_List
    
         Default_Entry ::= Default_Type Parameter_List
    
         Parameter_List ::= Parameter |
                            Parameter ',' Parameter_List
    
         Parameter ::= Parameter '=' Value |
                       Parameter '+=' Value |
                       Parameter '-=' Value |
                       '!'* Parameter
    
         Parameters may be flags, integer values, strings, or lists.  Flags are
         implicitly boolean and can be turned off via the '!' operator.  Some
         integer, string and list parameters may also be used in a boolean context
         to disable them.  Values may be enclosed in double quotes ("") when they
         contain multiple words.  Special characters may be escaped with a back-
         slash ('\').
    
         Lists have two additional assignment operators, += and -=.  These opera-
         tors are used to add to and delete from a list respectively.  It is not
         an error to use the -= operator to remove an element that does not exist
         Cmnd_Spec ::= Runas_Spec? SELinux_Spec? Tag_Spec* Cmnd
    
         Runas_Spec ::= '(' Runas_List? (':' Runas_List)? ')'
    
         SELinux_Spec ::= ('ROLE=role' | 'TYPE=type')
    
         Tag_Spec ::= ('NOPASSWD:' | 'PASSWD:' | 'NOEXEC:' | 'EXEC:' |
                       'SETENV:' | 'NOSETENV:' | 'LOG_INPUT:' | 'NOLOG_INPUT:' |
                       'LOG_OUTPUT:' | 'NOLOG_OUTPUT:')
    
         A user specification determines which commands a user may run (and as
         what user) on specified hosts.  By default, commands are run as root, but
         this can be changed on a per-command basis.
    
         The basic structure of a user specification is "who where = (as_whom)
         what".  Let's break that down into its constituent parts:
    
       Runas_Spec
         A Runas_Spec determines the user and/or the group that a command may be
         run as.  A fully-specified Runas_Spec consists of two Runas_Lists (as
         defined above) separated by a colon (':') and enclosed in a set of paren-
         theses.  The first Runas_List indicates which users the command may be
         run as via sudo's -u option.  The second defines a list of groups that
         can be specified via sudo's -g option.  If both Runas_Lists are speci-
         fied, the command may be run with any combination of users and groups
         listed in their respective Runas_Lists. If only the first is specified,
         the command may be run as any user in the list but no -g option may be
         specified.  If the first Runas_List is empty but the second is specified,
         the command may be run as the invoking user with the group set to any
         listed in the Runas_List.  If both Runas_Lists are empty, the command may
         only be run as the invoking user.  If no Runas_Spec is specified the com-
         mand may be run as root and no group may be specified.
    
         A Runas_Spec sets the default for the commands that follow it.  What this
         means is that for the entry:
    
         dgb     boulder = (operator) /bin/ls, /bin/kill, /usr/bin/lprm
    
         The user dgb may run /bin/ls, /bin/kill, and /usr/bin/lprm--but only as
         operator.  E.g.,
    
         $ sudo -u operator /bin/ls
    
         It is also possible to override a Runas_Spec later on in an entry.  If we
         modify the entry like so:
    
         dgb     boulder = (operator) /bin/ls, (root) /bin/kill, /usr/bin/lprm
    
         Then user dgb is now allowed to run /bin/ls as operator, but /bin/kill
         and /usr/bin/lprm as root.
    
         We can extend this to allow dgb to run /bin/ls with either the user or
    
         In the following example, user tcm may run commands that access a modem
         device file with the dialer group.
    
         tcm     boulder = (:dialer) /usr/bin/tip, /usr/bin/cu,\
                 /usr/local/bin/minicom
    
         Note that in this example only the group will be set, the command still
         runs as user tcm.  E.g.
    
         $ sudo -g dialer /usr/bin/cu
    
         Multiple users and groups may be present in a Runas_Spec, in which case
         the user may select any combination of users and groups via the -u and -g
         options.  In this example:
    
         alan    ALL = (root, bin : operator, system) ALL
    
         user alan may run any command as either user root or bin, optionally set-
         ting the group to operator or system.
    
       SELinux_Spec
         On systems with SELinux support, sudoers entries may optionally have an
         SELinux role and/or type associated with a command.  If a role or type is
         specified with the command it will override any default values specified
         in sudoers.  A role or type specified on the command line, however, will
         supersede the values in sudoers.
    
       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
         ing system supports it, the NOEXEC tag can be used to prevent a dynami-
         cally-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 dis-
         able the env_reset option from the command line via the -E option.  Addi-
         tionally, 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 man-
         ner.  If the command matched is ALL, the SETENV tag is implied for that
         command; this default may be overridden by use of the NOSETENV tag.
    
         LOG_INPUT and NOLOG_INPUT
    
         These tags override the value of the log_input option on a per-command
         basis.  For more information, see the description of log_input in the
         SUDOERS OPTIONS section below.
    
         LOG_OUTPUT and NOLOG_OUTPUT
    
         These tags override the value of the log_output option on a per-command
         basis.  For more information, see the description of log_output in the
         SUDOERS OPTIONS section below.
    
       Wildcards
         sudo allows shell-style wildcards (aka meta or glob characters) to be
         used in host names, path names and command line arguments in the sudoers
         file.  Wildcard matching is done via the POSIX glob(3) and fnmatch(3)
         routines.  Note that these are not regular expressions.
    
         *         Matches any set of zero or more characters.
    
         ?         Matches any single character.
    
         [...]     Matches any character in the specified range.
    
         [!...]    Matches any character not in the specified range.
    
         \x        For any character 'x', evaluates to 'x'.  This is used to
                   escape special characters such as: '*', '?', '[', and ']'.
    
         POSIX character classes may also be used if your system's glob(3) and
         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 direc-
         tives.
    
         This can be used, for example, to keep a site-wide sudoers file in addi-
         tion to a local, per-machine file.  For the sake of this example the
         site-wide sudoers 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
    
         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 prefer-
         ence to your own.  Please note that using ALL can be dangerous since in a
         command context, it allows the user to run any command on the system.
    
         An exclamation point ('!') can be used as a logical not operator in a
         list or alias as well as in front of a Cmnd.  This allows one to exclude
         certain values.  For the '!' operator to be effective, there must be
         something for it to exclude.  For example, to match all users except for
         root one would use:
    
             ALL,!root
    
         If the ALL, is omitted, as in:
    
             !root
    
         it would explicitly deny root but not match any other users.  This is
         different from a true "negation" operator.
    
         Note, however, that using a '!' in conjunction with the built-in ALL
         alias to allow a user to run "all but a few" commands rarely works as
         lier.  A list of all supported Defaults parameters, grouped by type, are
         listed below.
    
         Boolean Flags:
    
         always_set_home   If enabled, sudo will set the HOME environment variable
                           to the home directory of the target user (which is root
                           unless the -u option is used).  This effectively means
                           that the -H option is always implied.  Note that HOME
                           is already set when the the env_reset option is
                           enabled, so always_set_home is only effective for con-
                           figurations where either env_reset is disabled or HOME
                           is present in the env_keep list.  This flag is off by
                           default.
    
         authenticate      If set, users must authenticate themselves via a pass-
                           word (or other means of authentication) before they may
                           run commands.  This default may be overridden via the
                           PASSWD and NOPASSWD tags.  This flag is on by default.
    
         closefrom_override
                           If set, the user may use sudo's -C option which over-
                           rides the default starting point at which sudo begins
                           closing open file descriptors.  This flag is off by
                           default.
    
         compress_io       If set, and sudo is configured to log a command's input
                           or output, the I/O logs will be compressed using zlib.
                           This flag is on by default when sudo is compiled with
                           zlib support.
    
         env_editor        If set, visudo will use the value of the EDITOR or
                           VISUAL environment variables before falling back on the
                           default editor list.  Note that this may create a secu-
                           rity hole as it allows the user to run any arbitrary
                           command as root without logging.  A safer alternative
                           is to place a colon-separated list of editors in the
                           editor variable.  visudo will then only use the EDITOR
                           or VISUAL if they match a value specified in editor.
                           This flag is on by default.
    
         env_reset         If set, sudo will run the command in a minimal environ-
                           ment containing the TERM, PATH, HOME, MAIL, SHELL,
                           LOGNAME, USER, USERNAME and SUDO_* variables.  Any
                           variables in the caller's environment 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.
                           ially 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 con-
                           figured to use DNS for host name resolution.
    
                           If the system is configured to use the /etc/hosts file
                           in preference to DNS, the "canonical" host name may not
                           be fully-qualified.  The order that sources are queried
                           for hosts name resolution is usually specified in the
                           /etc/nsswitch.conf, /etc/netsvc.conf, /etc/host.conf,
                           or, in some cases, /etc/resolv.conf file.  In the
                           /etc/hosts file, the first host name of the entry is
                           considered to be the "canonical" name; subsequent names
                           are aliases that are not used by sudoers.  For example,
                           the following hosts file line for the machine "xyzzy"
                           has the fully-qualified domain name as the "canonical"
                           host name, and the short version as an alias.
    
                                 192.168.1.1    xyzzy.sudo.ws xyzzy
    
                           If the machine's hosts file entry is not formatted
                           properly, the fqdn option will not be effective if it
                           is queried before DNS.
    
                           Beware that when using DNS for host name resolution,
                           turning on fqdn requires sudoers to make DNS lookups
                           which renders sudo unusable if DNS stops working (for
                           example if the machine is disconnected from the net-
                           work).  Also note that just like with the hosts file,
                           you must use the "canonical" name as DNS knows it.
                           That is, you may not use a host alias (CNAME entry) due
                           to performance issues and the fact that there is no way
                           to get all aliases from DNS.
    
                           This flag is off by default.
    
         ignore_dot        If set, sudo will ignore "." or "" (both denoting cur-
                           rent directory) in the PATH environment variable; the
                           PATH itself is not modified.  This flag is on by
                           default.
                           incorrect password.  This flag is off by default.
    
         log_host          If set, the host name will be logged in the (non-sys-
                           log) sudo log file.  This flag is off by default.
    
         log_input         If set, sudo will run the command in a pseudo tty and
                           log all user input.  If the standard input is not con-
                           nected to the user's tty, due to I/O redirection or
                           because the command is part of a pipeline, that input
                           is also captured and stored in a separate log file.
    
                           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 unen-
                           crypted.  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 stan-
                           dard 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(8) util-
                           ity, 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
         mail_no_perms     If set, mail will be sent to the mailto user if the
                           invoking user is allowed to use sudo but the command
                           they are trying is not listed in their sudoers file
                           entry or is explicitly denied.  This flag is off by
                           default.
    
         mail_no_user      If set, mail will be sent to the mailto user if the
                           invoking user is not in the sudoers file.  This flag is
                           on by default.
    
         noexec            If set, all commands run via sudo will behave as if the
                           NOEXEC tag has been set, unless overridden by a EXEC
                           tag.  See the description of NOEXEC and EXEC below as
                           well as the Preventing shell escapes section at the end
                           of this manual.  This flag is off by default.
    
         path_info         Normally, sudo will tell the user when a command could
                           not be found in their PATH environment variable.  Some
                           sites may wish to disable this as it could be used to
                           gather information on the location of executables that
                           the normal user does not have access to.  The disadvan-
                           tage is that if the executable is simply not in the
                           user's PATH, sudo will tell the user that they are not
                           allowed to run it, which can be confusing.  This flag
                           is on by default.
    
         passprompt_override
                           The password prompt specified by passprompt will nor-
                           mally only be used if the password prompt provided by
                           systems such as PAM matches the string "Password:".  If
                           passprompt_override is set, passprompt will always be
                           used.  This flag is off by default.
    
         preserve_groups   By default, sudo will initialize the group vector to
                           the list of groups the target user is in.  When
                           preserve_groups is set, the user's existing group vec-
                           tor is left unaltered.  The real and effective group
                           IDs, however, are still set to match the target user.
                           This flag is off by default.
    
         pwfeedback        By default, sudo reads the password like most other
                           Unix programs, by turning off echo until the user hits
                           the return (or enter) key.  Some users become confused
                           by this as it appears to them that sudo has hung at
                           this point.  When pwfeedback is set, sudo will provide
                           visual feedback when the user presses a key.  Note that
                           this does have a security impact as an onlooker may be
                           able to determine the length of the password being
                           entered.  This flag is off by default.
    
         requiretty        If set, sudo will only run when the user is logged in
                           to a real tty.  When this flag is set, sudo can only be
                           of the password of the invoking user.  This flag is off
                           by default.
    
         runaspw           If set, sudo will prompt for the password of the user
                           defined by the runas_default option (defaults to root)
                           instead of the password of the invoking user.  This
                           flag is off by default.
    
         set_home          If enabled and sudo is invoked with the -s option the
                           HOME environment variable will be set to the home
                           directory of the target user (which is root unless the
                           -u option is used).  This effectively makes the -s
                           option imply -H.  Note that HOME is already set when
                           the the env_reset option is enabled, so set_home is
                           only effective for configurations where either
                           env_reset is disabled or HOME is present in the
                           env_keep list.  This flag is off by default.
    
         set_logname       Normally, sudo will set the LOGNAME, USER and USERNAME
                           environment variables to the name of the target user
                           (usually root unless the -u option is given).  However,
                           since some programs (including the RCS revision control
                           system) use LOGNAME to determine the real identity of
                           the user, it may be desirable to change this behavior.
                           This can be done by negating the set_logname option.
                           Note that if the env_reset option has not been dis-
                           abled, 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, environ-
                           ment variables set via the command line are not subject
                           to the restrictions imposed by env_check, env_delete,
                           or env_keep.  As such, only trusted users should be
                           allowed to set variables in this manner.  This flag is
                           off by default.
    
         shell_noargs      If set and sudo is invoked with no arguments it acts as
                           if the -s option had been given.  That is, it runs a
                           shell as root (the shell is determined by the SHELL
                           environment variable if it is set, falling back on the
                           shell listed in the invoking user's /etc/passwd entry
                           if not).  This flag is off by default.
    
                           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 spec-
                           ify 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.  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 visi-
                           ble on the screen.  This makes it possible to run
                           things like "ssh somehost sudo ls" since by default,
                           ssh(1) does not allocate a tty when running a command.
                           This flag is off by default.
    
         Integers:
    
         closefrom         Before it executes a command, sudo will close all open
                           file descriptors other than standard input, standard
                           output and standard error (ie: file descriptors 0-2).
                           The closefrom option can be used to specify a different
                           file descriptor at which to start closing.  The default
                           is 3.
    
         passwd_tries      The number of tries a user gets to enter his/her pass-
                           word before sudo logs the failure and exits.  The
                           default is 3.
    
         timestamp_timeout
                           Number of minutes that can elapse before sudo will ask
                           for a passwd again.  The timeout may include a frac-
                           tional component if minute granularity is insufficient,
                           for example 2.5.  The default is 5.  Set this to 0 to
                           always prompt for a password.  If set to a value less
                           than 0 the user's time stamp will never expire.  This
                           can be used to allow users to create or delete their
                           own time stamps via "sudo -v" and "sudo -k" respec-
                           tively.
    
         umask             Umask to use when running the command.  Negate this
                           option or set it to 0777 to preserve the user's umask.
                           The actual umask that is used will be the union of the
                           user's umask and the value of the umask option, which
                           defaults to 0022.  This guarantees that sudo never low-
                           ers the umask when running a command.  Note: on systems
                           that use PAM, the default PAM configuration may specify
                           its own umask which will override the value set in
                           sudoers.
    
         Strings:
    
         badpass_message   Message that is displayed if a user enters an incorrect
                           password.  The default is Sorry, try again. unless
                           insults are enabled.
    
         editor            A colon (':') separated list of editors allowed to be
                           used with visudo.  visudo will choose the editor that
                           matches the user's EDITOR environment variable if pos-
                           sible, or the first editor in the list that exists and
                           is executable.  The default is /usr/local/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 sup-
                           ported:
    
                           %{seq}
                                 expanded to a monotonically increasing base-36
                                 sequence number, such as 0100A5, where every two
                                 digits are used to form a new directory, e.g.
                                 01/00/A5
    
                           %{user}
                                 expanded to the invoking user's login name
                                 expanded to the local host name without the
                                 domain name
    
                           %{command}
                                 expanded to the base name of the command being
                                 run
    
                           In addition, any escape sequences supported by the sys-
                           tem's strftime(3) function will be expanded.
    
                           To include a literal '%' character, the string '%%'
                           should be used.
    
         iolog_file        The path name, relative to iolog_dir, in which to store
                           input/output logs when the log_input or log_output
                           options are enabled or when the LOG_INPUT or LOG_OUTPUT
                           tags are present for a command.  Note that iolog_file
                           may contain directory components.  The default is
                           "%{seq}".
    
                           See the iolog_dir option above for a list of supported
                           percent ('%') escape sequences.
    
                           In addition to the escape sequences, path names that
                           end in six or more Xs will have the Xs replaced with a
                           unique combination of digits and letters, similar to
                           the mktemp(3) function.
    
         mailsub           Subject of the mail sent to the mailto user.  The
                           escape %h will expand to the host name of the machine.
                           Default is "*** SECURITY information for %h ***".
    
         noexec_file       This option is no longer supported.  The path to the
                           noexec file should now be set in the /etc/sudo.conf
                           file.
    
         passprompt        The default prompt to use when asking for a password;
                           can be overridden via the -p option or the SUDO_PROMPT
                           environment variable.  The following percent ('%')
                           escape sequences are supported:
    
                           %H    expanded to the local host name including the
                                 domain name (only if the machine's host name is
                                 fully qualified or the fqdn option is set)
    
                           %h    expanded to the local host name without the
                                 domain name
    
                           %p    expanded to the user whose password is being
                                 asked for (respects the rootpw, targetpw and
                                 runaspw flags in sudoers)
    
    
         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 unsuc-
                           cessfully.  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 success-
                           fully.  Defaults to notice.
    
                           See syslog_badpri for the list of supported syslog pri-
                           orities.
    
         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 /var/db/sudo.
    
         timestampowner    The owner of the time stamp directory and the time
                           stamps stored therein.  The default is root.
    
         type              The default SELinux type to use when constructing a new
                           security context to run the command.  The default type
                           may be overridden on a per-command basis in sudoers or
                           via command line options.  This option is only avail-
                           able when sudo is built with SELinux support.
    
         Strings that can be used in a boolean context:
    
         env_file      The env_file option specifies the fully qualified path to a
                       file containing variables to be set in the environment of
                       the program being run.  Entries in this file should either
                       be of the form "VARIABLE=value" or "export VARIABLE=value".
                       The value may optionally be surrounded by single or double
                       quotes.  Variables in this file are subject to other sudo
                       environment settings such as env_keep and env_check.
    
         exempt_group  Users in this group are exempt from password and PATH
                       requirements.  The group name specified should not include
                       a % prefix.  This is not set by default.
    
         group_plugin  A string containing a sudoers group plugin with optional
                       arguments.  This can be used to implement support for the
                       nonunix_group syntax described earlier.  The string should
                       consist of the plugin path, either fully-qualified or rela-
                       along with the password prompt.  It has the following pos-
                       sible values:
    
                       always  Always lecture the user.
    
                       never   Never lecture the user.
    
                       once    Only lecture the user the first time they run sudo.
    
                       If no value is specified, a value of once is implied.
                       Negating the option results in a value of never being used.
                       The default value is once.
    
         lecture_file  Path to a file containing an alternate sudo lecture that
                       will be used in place of the standard lecture if the named
                       file exists.  By default, sudo uses a built-in lecture.
    
         listpw        This option controls when a password will be required when
                       a user runs sudo with the -l option.  It has the following
                       possible values:
    
                       all       All the user's sudoers entries for the current
                                 host must have the NOPASSWD flag set to avoid
                                 entering a password.
    
                       always    The user must always enter a password to use the
                                 -l option.
    
                       any       At least one of the user's sudoers entries for
                                 the current host must have the NOPASSWD flag set
                                 to avoid entering a password.
    
                       never     The user need never enter a password to use the
                                 -l option.
    
                       If no value is specified, a value of any is implied.
                       Negating the option results in a value of never being used.
                       The default value is any.
    
         logfile       Path to the sudo log file (not the syslog log file).  Set-
                       ting a path turns on logging to a file; negating this
                       option turns it off.  By default, sudo logs via syslog.
    
         mailerflags   Flags to use when invoking mailer. Defaults to -t.
    
         mailerpath    Path to mail program used to send warning mail.  Defaults
                       to the path to sendmail found at configure time.
    
         mailfrom      Address to use for the "from" address when sending warning
                       and error mail.  The address should be enclosed in double
                       quotes ("") to protect against sudo interpreting the @
                       sign.  Defaults to the name of the user running sudo.
                       to disable syslog logging).  Defaults to authpriv.
    
                       The following syslog facilities are supported: authpriv (if
                       your OS supports it), auth, daemon, user, local0, local1,
                       local2, local3, local4, local5, local6, and local7.
    
         verifypw      This option controls when a password will be required when
                       a user runs sudo with the -v option.  It has the following
                       possible values:
    
                       all     All the user's sudoers entries for the current host
                               must have the NOPASSWD flag set to avoid entering a
                               password.
    
                       always  The user must always enter a password to use the -v
                               option.
    
                       any     At least one of the user's sudoers entries for the
                               current host must have the NOPASSWD flag set to
                               avoid entering a password.
    
                       never   The user need never enter a password to use the -v
                               option.
    
                       If no value is specified, a value of all is implied.
                       Negating the option results in a value of never being used.
                       The default value is all.
    
         Lists that can be used in a boolean context:
    
         env_check         Environment variables to be removed from the user's
                           environment if unless they are considered "safe".  For
                           all variables except TZ, "safe" means that the vari-
                           able's value does not contain any '%' or '/' charac-
                           ters.  This can be used to guard against printf-style
                           format vulnerabilities in poorly-written programs.  The
                           TZ variable is considerd unsafe if any of the following
                           are true:
    
                           ?   It consists of a fully-qualified path name, option-
                               ally prefixed with a colon (':'), that does not
                               match the location of the zoneinfo directory.
    
                           ?   It contains a .. path element.
    
                           ?   It contains white space or non-printable charac-
                               ters.
    
                           ?   It is longer than the value of PATH_MAX.
    
                           The argument may be a double-quoted, space-separated
                           list or a single value without double-quotes.  The list
                           using the =, +=, -=, and ! operators respectively.  The
                           default list of environment variables to remove is dis-
                           played when sudo is run by root with the -V option.
                           Note that many operating systems will remove poten-
                           tially dangerous variables from the environment of any
                           setuid process (such as sudo).
    
         env_keep          Environment variables to be preserved in the user's
                           environment when the env_reset option is in effect.
                           This allows fine-grained control over the environment
                           sudo-spawned processes will receive.  The argument may
                           be a double-quoted, space-separated list or a single
                           value without double-quotes.  The list can be replaced,
                           added to, deleted from, or disabled by using the =, +=,
                           -=, and ! operators respectively.  The default list of
                           variables to keep is displayed when sudo is run by root
                           with the -V option.
    
    
    

    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 ter-
                       minal present.
    
         cwd           The current working directory that sudo was run in.
    
         Messages are logged using the locale specified by sudoers_locale, which
         defaults to the "C" locale.
    
       Denied command log entries
         If the user is not allowed to run the command, the reason for the denial
         will follow the user name.  Possible reasons include:
    
         user NOT in sudoers
           The user is not listed in the sudoers file.
    
         user NOT authorized on host
           The user is listed in the sudoers file but is not allowed to run com-
           mands on the host.
    
         command not allowed
           The user is listed in the sudoers file for the host but they are not
           allowed to run the specified command.
    
         3 incorrect password attempts
           The user failed to enter their password after 3 tries.  The actual num-
           ber of tries will vary based on the number of failed attempts and the
           value of the passwd_tries option.
    
         a password is required
           sudo's -n option was specified but a password was required.
    
         sorry, you are not allowed to set the following environment variables
           The user specified environment variables on the command line that were
           not allowed by sudoers.
    
       Error log entries
         If an error occurs, sudoers will log a message and, in most cases, send a
         message to the administrator via email.  Possible errors include:
    
         parse error in /etc/sudoers near line N
           sudoers encountered an error when parsing the specified file.  In some
           cases, the actual error may be one line above or below the line number
           listed, depending on the type of error.
    
         problem with defaults entries
           The sudoers file contains one or more unknown Defaults settings.  This
           does not prevent sudo from running, but the sudoers file should be
           checked using visudo.
    
         timestamp owner (username): No such user
           The time stamp directory owner, as specified by the timestampowner set-
           ting, could not be found in the password database.
    
         unable to open/read /etc/sudoers
           The sudoers file could not be opened for reading.  This can happen when
           the sudoers file is located on a remote file system that maps user ID 0
           to a different value.  Normally, sudoers tries to open sudoers using
           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
           /etc/sudo.conf 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 /etc/sudo.conf 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 /etc/sudo.conf file.
    
         unable to open /var/db/sudo/username/ttyname
           sudoers was unable to read or create the user's time stamp file.
    
         unable to write to /var/db/sudo/username/ttyname
           sudoers was unable to write to the user's time stamp file.
    
         unable to mkdir to /var/db/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
    
         #   Path askpass /path/to/askpass
         #   Path noexec /path/to/sudo_noexec.so
         #   Debug sudo /var/log/sudo_debug all@warn
         #   Set disable_coredump true
         #
         # The plugin_path is relative to /usr/libexec unless
         #   fully qualified.
         # The plugin_name corresponds to a global symbol in the plugin
         #   that contains the plugin interface structure.
         # The plugin_options are optional.
         #
         Plugin policy_plugin sudoers.so
         Plugin io_plugin sudoers.so
    
       Plugin options
         Starting with sudo 1.8.5, it is possible to pass options to the sudoers
         plugin.  Options may be listed after the path to the plugin (i.e. after
         sudoers.so); multiple options should be space-separated.  For example:
    
         Plugin sudoers_policy sudoers.so sudoers_file=/etc/sudoers sudoers_uid=0 sudoers_gid=0 sudoers_mode=0440
    
         The following plugin options are supported:
    
         sudoers_file=pathname
                   The sudoers_file option can be used to override the default
                   path to the sudoers file.
    
         sudoers_uid=uid
                   The sudoers_uid option 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 option can be used to override the default
                   group of the sudoers file.  It should be specified as a numeric
                   group ID.
    
         sudoers_mode=mode
                   The sudoers_mode option can be used to override the default
                   file mode for the sudoers file.  It should be specified as an
                   octal value.
    
       Debug flags
         Versions 1.8.4 and higher of the sudoers plugin supports a debugging
         framework that can help track down what the plugin is doing internally if
         there is a problem.  This can be configured in the /etc/sudo.conf file as
         described in sudo(8).
    
         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:
    
         defaults  sudoers Defaults settings
    
         env       environment handling
    
         ldap      LDAP-based sudoers
    
         logging   logging support
    
         match     matching of users, groups, hosts and netgroups in sudoers
    
         netif     network interface handling
    
         nss       network service switch handling in sudoers
    
         parser    sudoers file parsing
    
         perms     permission setting
    
         plugin    The equivalent of main for the plugin.
    
         pty       pseudo-tty related code
    
         rbtree    redblack tree internals
    
         util      utility functions
    
    
    

    FILES

         /etc/sudo.conf            Sudo front end configuration
    
         /etc/sudoers              List of who can run what
    
         /etc/group                Local groups file
    
         /etc/netgroup             List of network groups
    
         /var/log/sudo-io          I/O log files
    
         /var/db/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!
                         SGI = grolsch, dandelion, black :\
                         ALPHA = widget, thalamus, foobar :\
                         HPPA = boa, nag, python
         Host_Alias      CUNETS = 128.138.0.0/255.255.0.0
         Host_Alias      CSNETS = 128.138.243.0, 128.138.204.0/24, 128.138.242.0
         Host_Alias      SERVERS = master, mail, www, ns
         Host_Alias      CDROM = orion, perseus, hercules
    
         # Cmnd alias specification
         Cmnd_Alias      DUMPS = /usr/bin/mt, /usr/sbin/dump, /usr/sbin/rdump,\
                                 /usr/sbin/restore, /usr/sbin/rrestore
         Cmnd_Alias      KILL = /usr/bin/kill
         Cmnd_Alias      PRINTING = /usr/sbin/lpc, /usr/bin/lprm
         Cmnd_Alias      SHUTDOWN = /usr/sbin/shutdown
         Cmnd_Alias      HALT = /usr/sbin/halt
         Cmnd_Alias      REBOOT = /usr/sbin/reboot
         Cmnd_Alias      SHELLS = /usr/bin/sh, /usr/bin/csh, /usr/bin/ksh,\
                                  /usr/local/bin/tcsh, /usr/bin/rsh,\
                                  /usr/local/bin/zsh
         Cmnd_Alias      SU = /usr/bin/su
         Cmnd_Alias      PAGERS = /usr/bin/more, /usr/bin/pg, /usr/bin/less
    
         Here we override some of the compiled in default values.  We want sudo to
         log via syslog(3) using the auth facility in all cases.  We don't want to
         subject the full time staff to the sudo lecture, user millert need not
         give a password, and we don't want to reset the LOGNAME, USER or USERNAME
         environment variables when running commands as root.  Additionally, on
         the machines in the SERVERS Host_Alias, we keep an additional local log
         file and make sure we log the year in each log line since the log entries
         will be kept around for several years.  Lastly, we disable shell escapes
         for the commands in the PAGERS Cmnd_Alias (/usr/bin/more, /usr/bin/pg and
         /usr/bin/less).
    
         # Override built-in defaults
         Defaults                syslog=auth
         Defaults>root           !set_logname
         Defaults:FULLTIMERS     !lecture
         Defaults:millert        !authenticate
         Defaults@SERVERS        log_year, logfile=/var/log/sudo.log
         Defaults!PAGERS         noexec
    
         The User specification is the part that actually determines who may run
         what.
    
         root            ALL = (ALL) ALL
         %wheel          ALL = (ALL) ALL
    
         We let root and any user in group wheel run any command on any host as
         any user.
    
         FULLTIMERS      ALL = NOPASSWD: ALL
    
         indicating it is a class C network.  For the other networks in CSNETS,
         the local machine's netmask will be used during matching.
    
         lisa            CUNETS = ALL
    
         The user lisa may run any command on any host in the CUNETS alias (the
         class B network 128.138.0.0).
    
         operator        ALL = DUMPS, KILL, SHUTDOWN, HALT, REBOOT, PRINTING,\
                         sudoedit /etc/printcap, /usr/oper/bin/
    
         The operator user may run commands limited to simple maintenance.  Here,
         those are commands related to backups, killing processes, the printing
         system, shutting down the system, and any commands in the directory
         /usr/oper/bin/.
    
         joe             ALL = /usr/bin/su operator
    
         The user joe may only su(1) to operator.
    
         pete            HPPA = /usr/bin/passwd [A-Za-z]*, !/usr/bin/passwd root
    
         %opers          ALL = (: ADMINGRP) /usr/sbin/
    
         Users in the opers group may run commands in /usr/sbin/ as themselves
         with any group in the ADMINGRP Runas_Alias (the adm and oper groups).
    
         The user pete is allowed to change anyone's password except for root on
         the HPPA machines.  Note that this assumes passwd(1) does not take multi-
         ple 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.
    
         SHELLS Cmnd_Aliases.
    
         steve           CSNETS = (operator) /usr/local/op_commands/
    
         The user steve may run any command in the directory /usr/local/op_com-
         mands/ but only as user operator.
    
         matt            valkyrie = KILL
    
         On his personal workstation, valkyrie, matt needs to be able to kill hung
         processes.
    
         WEBMASTERS      www = (www) ALL, (root) /usr/bin/su www
    
         On the host www, any user in the WEBMASTERS User_Alias (will, wendy, and
         wim), may run any command as user www (which owns the web pages) or sim-
         ply su(1) to www.
    
         ALL             CDROM = NOPASSWD: /sbin/umount /CDROM,\
                         /sbin/mount -o nosuidnodev /dev/cd0a /CDROM
    
         Any user may mount or unmount a CD-ROM on the machines in the CDROM
         Host_Alias (orion, perseus, hercules) without entering a password.  This
         is a bit tedious for users to type, so it is a prime candidate for encap-
         sulating in a shell script.
    
    
    

    SECURITY NOTES

       Limitations of the '!' operator
         It is generally not effective to "subtract" commands from ALL using the
         '!' operator.  A user can trivially circumvent this by copying the
         desired command to a different name and then executing that.  For exam-
         ple:
    
         bill    ALL = ALL, !SU, !SHELLS
    
         Doesn't really prevent bill from running the commands listed in SU or
         SHELLS since he can simply copy those commands to a different name, or
         use a shell escape from an editor or other program.  Therefore, these
         kind of restrictions should be considered advisory at best (and rein-
         forced by policy).
    
         In general, if a user has sudo ALL there is nothing to prevent them from
         creating their own program that gives them a root shell (or making their
         own copy of a shell) regardless of any '!' elements in the user specifi-
         cation.
    
       Security implications of fast_glob
         If the fast_glob option is in use, it is not possible to reliably negate
         commands where the path name includes globbing (aka wildcard) characters.
         This is because the C library's fnmatch(3) function cannot resolve rela-
         tive paths.  While this is typically only an inconvenience for rules that
         grant privileges, it can result in a security issue for rules that sub-
         a user bypass sudo's access control and logging.  Common programs that
         permit shell escapes include shells (obviously), editors, paginators,
         mail and terminal programs.
    
         There are two basic approaches to this problem:
    
         restrict  Avoid giving users access to commands that allow the user to
                   run arbitrary commands.  Many editors have a restricted mode
                   where shell escapes are disabled, though sudoedit is a better
                   solution to running editors via sudo.  Due to the large number
                   of programs that offer shell escapes, restricting users to the
                   set of programs that do not is often unworkable.
    
         noexec    Many systems that support shared libraries have the ability to
                   override default library functions by pointing an environment
                   variable (usually LD_PRELOAD) to an alternate shared library.
                   On such systems, sudo's noexec functionality can be used to
                   prevent a program run by sudo from executing any other pro-
                   grams.  Note, however, that this applies only to native dynami-
                   cally-linked executables.  Statically-linked executables and
                   foreign executables running under binary emulation are not
                   affected.
    
                   The noexec feature is known to work on SunOS, Solaris, *BSD,
                   Linux, IRIX, Tru64 UNIX, MacOS X, HP-UX 11.x and AIX 5.3 and
                   above.  It should be supported on most operating systems that
                   support the LD_PRELOAD environment variable.  Check your oper-
                   ating system's manual pages for the dynamic linker (usually
                   ld.so, ld.so.1, dyld, dld.sl, rld, or loader) to see if
                   LD_PRELOAD is supported.
    
                   To enable noexec for a command, use the NOEXEC tag as docu-
                   mented in the User Specification section above.  Here is that
                   example again:
    
                   aaron   shanty = NOEXEC: /usr/bin/more, /usr/bin/vi
    
                   This allows user aaron to run /usr/bin/more and /usr/bin/vi
                   with noexec enabled.  This will prevent those two commands from
                   executing other commands (such as a shell).  If you are unsure
                   whether or not your system is capable of supporting noexec you
                   can always just try it out and check whether shell escapes work
                   when noexec is enabled.
    
         Note that restricting shell escapes is not a panacea.  Programs running
         as root are still capable of many potentially hazardous operations (such
         as changing or overwriting files) that could lead to unintended privilege
         escalation.  In the specific case of an editor, a safer approach is to
         give the user permission to run sudoedit.
    
       Time stamp file checks
         sudoers will check the ownership of its time stamp directory
         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 monotoni-
         cally 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 fea-
         ture as it is not universally available.
    
    
    

    SEE ALSO

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

    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 syntacti-
         cally 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, includ-
         ing, but not limited to, the implied warranties of merchantability and
         fitness for a particular purpose are disclaimed.  See the LICENSE file
         distributed with sudo or http://www.sudo.ws/sudo/license.html for com-
         plete details.
    
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