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OpenSolaris 2009.06 - man page for sudoers (opensolaris section 4)

SUDOERS(4)			       MAINTENANCE COMMANDS			       SUDOERS(4)

NAME
       sudoers - list of which users may execute what

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

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

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

       Quick guide to EBNF

       EBNF is a concise and exact way of describing the grammar of a language.  Each EBNF defi-
       nition 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 differ-
       ent 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 ::= '!'* username |
		 '!'* '%'group |
		 '!'* '+'netgroup |
		 '!'* User_Alias

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

	Runas_List ::= Runas_User |
		       Runas_User ',' Runas_List

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

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

	Host_List ::= Host |
		      Host ',' Host_List

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

       A Host_List is made up of one or more hostnames, IP addresses, network numbers, netgroups
       (prefixed with '+') and other aliases.  Again, the value of an item may be negated with
       the '!' operator.  If you do not specify a netmask 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 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 hostname may
       include shell-style wildcards (see the Wildcards section below), but unless the hostname
       command on your machine returns the fully qualified hostname, you'll need to use the fqdn
       option for wildcards to be useful.

	Cmnd_List ::= Cmnd |
		      Cmnd ',' Cmnd_List

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

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

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

       If a Cmnd has associated command line arguments, then the arguments in the Cmnd must match
       exactly those given by the user on the command line (or match the wildcards if there are
       any).  Note that the following characters must be escaped with a '\' if they are used in
       command arguments: ',', ':', '=', '\'.  The special command "sudoedit" is used to permit a
       user to run sudo with the -e flag (or as sudoedit).  It may take command line arguments
       just as a normal command does.

       Defaults

       Certain configuration options may be changed from their default values at runtime via one
       or more Default_Entry lines.  These may affect all users on any host, all users on a spe-
       cific host, a specific user, or commands being run as a specific user.

	Default_Type ::= 'Defaults' |
			 'Defaults' '@' Host_List |
			 'Defaults' ':' User_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.

       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? Tag_Spec* Cmnd

	Runas_Spec ::= '(' Runas_List ')'

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

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

       Let's break that down into its constituent parts:

       Runas_Spec

       A Runas_Spec is simply a Runas_List (as defined above) enclosed in a set of parentheses.
       If you do not specify a Runas_Spec in the user specification, a default Runas_Spec of root
       will be used.  A Runas_Spec sets the default for commands that follow it.  What this means
       is that for the entry:

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

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

	$ sudo -u operator /bin/ls.

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

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

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

       Tag_Spec

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

       NOPASSWD and PASSWD

       By default, sudo requires that a user authenticate him or herself before running a com-
       mand.  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.  Con-
       versely, the PASSWD tag can be used to reverse things.  For example:

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

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

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

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

       By default, if the NOPASSWD tag is applied to any of the entries for a user on the current
       host, he or she will be able to run sudo -l without a password.	Additionally, a user may
       only run sudo -v without a password if the NOPASSWD tag is present for all a user's
       entries that pertain to the current host.  This behavior may be overridden via the veri-
       fypw 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, any environment variables set on the command line way
       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 com-
       mand matched is ALL, the SETENV tag is implied for that command; this default may be over-
       ridden by use of the UNSETENV tag.

       Wildcards

       sudo allows shell-style wildcards (aka meta or glob characters) to be used in pathnames as
       well as command line arguments in the sudoers file.  Wildcard matching is done via the
       POSIX fnmatch(3) routine.  Note that these are not regular expressions.

       *       Matches any set of zero or more characters.

       ?       Matches any single character.

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

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

       \x      For any character "x", evaluates to "x".  This is used to escape special charac-
	       ters such as: "*", "?", "[", and "}".

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

	   /usr/bin/*

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

       Exceptions to wildcard rules

       The following exceptions apply to the above rules:

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

       Other special characters and reserved words

       The pound sign ('#') is used to indicate a comment (unless it is part of a #include direc-
       tive or unless it occurs in the context of a user name and is followed by one or more dig-
       its, in which case it is treated as a uid).  Both the comment character and any text after
       it, up to the end of the line, are ignored.

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

       An exclamation point ('!') can be used as a logical not operator both in an alias and in
       front of a Cmnd.  This allows one to exclude certain values.  Note, however, that using a
       ! in conjunction with the built-in ALL alias to allow a user to run "all but a few" com-
       mands rarely works as intended (see SECURITY NOTES below).

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

       Whitespace between elements in a list as well as special syntactic characters in a User
       Specification ('=', ':', '(', ')') is optional.

       The following characters must be escaped with a backslash ('\') when used as part of a
       word (e.g. a username or hostname): '@', '!', '=', ':', ',', '(', ')', '\'.

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.

       Flags:

       always_set_home If set, sudo will set the HOME environment variable to the home directory
		       of the target user (which is root unless the -u option is used).  This
		       effectively means that the -H flag is always implied.  This flag is off by
		       default.

       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.

       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 com-
		       mand 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 reset the environment to only contain the LOGNAME,
		       SHELL, USER, USERNAME and the SUDO_* variables.	Any variables in the
		       caller's environment that match the env_keep and env_check lists are then
		       added.  The default contents of the env_keep and env_check lists are dis-
		       played when sudo is run by root with the -V option.  If sudo was compiled
		       with the SECURE_PATH option, its value will be used for the PATH environ-
		       ment variable.  This flag is on by default.

       fqdn	       Set this flag if you want to put fully qualified hostnames in the sudoers
		       file.  I.e., instead of myhost you would use myhost.mydomain.edu.  You may
		       still use the short form if you wish (and even mix the two).  Beware that
		       turning on fqdn requires sudo to make DNS lookups which may make sudo
		       unusable if DNS stops working (for example if the machine is not plugged
		       into the network).  Also note that you must use the host's official name
		       as DNS knows it.  That is, you may not use a host alias (CNAME entry) due
		       to performance issues and the fact that there is no way to get all aliases
		       from DNS.  If your machine's hostname (as returned by the hostname com-
		       mand) is already fully qualified you shouldn't need to set fqdn.  This
		       flag is off by default.

       ignore_dot      If set, sudo will ignore '.' or '' (current dir) in the PATH environment
		       variable; the PATH itself is not modified.  This flag is off by default.
		       Currently, while it is possible to set ignore_dot in sudoers, its value is
		       not used.  This option should be considered read-only (it will be fixed in
		       a future version of sudo).

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

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

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

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

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

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

       mail_badpass    Send mail to the mailto user if the user running sudo does not enter the
		       correct password.  This flag is off by default.

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

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

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

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

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

       passprompt_override
		       The password prompt specified by passprompt will normally only be used if
		       the passwod prompt provided by systems such as PAM matches the string
		       "Password:".  If passprompt_override is set, passprompt will always be
		       used.  This flag is off by default.

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

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

       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 and 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 set and sudo is invoked with the -s flag the HOME environment variable
		       will be set to the home directory of the target user (which is root unless
		       the -u option is used).	This effectively makes the -s flag imply -H.
		       This flag is off by default.

       set_logname     Normally, sudo will set the LOGNAME, USER and USERNAME environment vari-
		       ables to the name of the target user (usually root unless the -u flag 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_log-
		       name.  This flag is off by default.

       setenv	       Allow the user to disable the env_reset option from the command line.
		       Additionally, environment variables set via the command line are not sub-
		       ject 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 flag had
		       been given.  That is, it runs a shell as root (the shell is determined by
		       the SHELL environment variable if it is set, falling back on the shell
		       listed in the invoking user's /etc/passwd entry if not).  This flag is off
		       by default.

       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 pro-
		       gram is run setuid.  This option is only effective on systems with either
		       the setreuid() or setresuid() function.	This flag is off by default.

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

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

       Integers:

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

       Integers that can be used in a boolean context:

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

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

       timestamp_timeout
		       Number of minutes that can elapse before sudo will ask for a passwd again.
		       The default is 5.  Set this to 0 to always prompt for a password.  If set
		       to a value less than 0 the user's timestamp will never expire.  This can
		       be used to allow users to create or delete their own timestamps via sudo
		       -v and sudo -k respectively.

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

       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 the path to vi on your system.

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

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

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

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

		       %h  expanded to the local hostname 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:.

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

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

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

       timestampdir    The directory in which sudo stores its timestamp files.	The default is
		       /var/run/sudo.

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

       Strings that can be used in a boolean context:

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

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

		   always  Always lecture the user.

		   never   Never lecture the user.

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

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

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

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

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

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

		   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 flag.

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

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

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

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

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

       syslog	   Syslog facility if syslog is being used for logging (negate to disable syslog
		   logging).  Defaults to local2.

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

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

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

		   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 flag.

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

       Lists that can be used in a boolean context:

       env_check       Environment variables to be removed from the user's environment if the
		       variable's value contains % or / characters.  This can be used to guard
		       against printf-style format 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, vari-
		       ables 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.  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 dou-
		       ble-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.

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

FILES
       /etc/sudoers	       List of who can run what

       /etc/group	       Local groups file

       /etc/netgroup	       List of network groups

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

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

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

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

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

	# Cmnd alias specification
	Cmnd_Alias     DUMPS = /usr/bin/mt, /usr/sbin/dump, /usr/sbin/rdump,\
			       /usr/sbin/restore, /usr/sbin/rrestore
	Cmnd_Alias     KILL = /usr/bin/kill
	Cmnd_Alias     PRINTING = /usr/sbin/lpc, /usr/bin/lprm
	Cmnd_Alias     SHUTDOWN = /usr/sbin/shutdown
	Cmnd_Alias     HALT = /usr/sbin/halt
	Cmnd_Alias     REBOOT = /usr/sbin/reboot
	Cmnd_Alias     SHELLS = /usr/bin/sh, /usr/bin/csh, /usr/bin/ksh, \
				/usr/local/bin/tcsh, /usr/bin/rsh, \
				/usr/local/bin/zsh
	Cmnd_Alias     SU = /usr/bin/su
	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 sys-
       log(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.  Addition-
       ally, on the machines in the SERVERS Host_Alias, we keep an additional local log file and
       make sure we log the year in each log line since the log entries will be kept around for
       several years.  Lastly, we disable shell escapes for the commands in the PAGERS Cmnd_Alias
       (/usr/bin/more, /usr/bin/pg and /usr/bin/less).

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

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

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

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

	FULLTIMERS     ALL = NOPASSWD: ALL

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

	PARTTIMERS     ALL = ALL

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

	jack	       CSNETS = ALL

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

	lisa	       CUNETS = ALL

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

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

       The operator user may run commands limited to simple maintenance.  Here, those are com-
       mands related to backups, killing processes, the printing system, shutting down the sys-
       tem, 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-z]*, !/usr/bin/passwd root

       The user pete is allowed to change anyone's password except for root on the HPPA machines.
       Note that this assumes passwd(1) does not take multiple usernames on the command line.

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

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

	jim	       +biglab = ALL

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

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

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

	fred	       ALL = (DB) NOPASSWD: ALL

       The user fred can run commands as any user in the DB Runas_Alias (oracle or sybase) with-
       out giving a password.

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

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

	jen	       ALL, !SERVERS = ALL

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

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

       For any machine in the SERVERS Host_Alias, jill may run any commands in the directory
       /usr/bin/ except for those commands belonging to the SU and SHELLS Cmnd_Aliases.

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

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

	matt	       valkyrie = KILL

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

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

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

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

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

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

	   bill        ALL = ALL, !SU, !SHELLS

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

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.  Com-
       mon 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 com-
		 mands.  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 if 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.  Stat-
		 ically-linked executables and foreign executables running under binary emulation
		 are not affected.

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

		     sudo -V | grep "dummy exec"

		 If the resulting output contains a line that begins with:

		     File containing dummy exec functions:

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

		 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 see if it works.

       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 ALSO
       rsh(1), su(1), fnmatch(3), sudo(1m), 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 syntactically incorrect sudoers file.

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

BUGS
       If you feel you have found a bug in sudo, please submit a bug report at
       http://www.sudo.ws/sudo/bugs/

SUPPORT
       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 lim-
       ited 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.

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

       +--------------------+----------------------+
       |  ATTRIBUTE TYPE    |	ATTRIBUTE VALUE    |
       +--------------------+----------------------+
       |Availability	    | SUNWsudor, SUNWsudou |
       +--------------------+----------------------+
       |Interface Stability | Uncommitted	   |
       +--------------------+----------------------+
NOTES
       sudo does not create audit(2) records; for a Role Based administration solution that per-
       forms auditing of all actions, please refer to rbac(5).

       Source for sudo is available on http://opensolaris.org.

1.6.9p17				   Jun 21, 2008 			       SUDOERS(4)


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