path: root/sudoers.cat

SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


NNAAMMEE
       sudoers - list of which users may execute what

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

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

       The _s_u_d_o_e_r_s 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.

   QQuuiicckk gguuiiddee ttoo EEBBNNFF
       EBNF is a concise and exact way of describing the grammar
       of a language.  Each EBNF definition is made up of
       _p_r_o_d_u_c_t_i_o_n _r_u_l_e_s.  E.g.,

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

       Each _p_r_o_d_u_c_t_i_o_n _r_u_l_e references others and thus makes up a
       grammar for the language.  EBNF also contains the
       following operators, which many readers will recognize
       from regular expressions.  Do not, however, confuse them
       with "wildcard" characters, which have different meanings.

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

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

       +   Means that the preceding symbol (or group of symbols)
           may appear one or more times.

       Parentheses may be used to group symbols together.  For
       clarity, we will use single quotes ('') to designate what
       is a verbatim character string (as opposed to a symbol
       name).

   AAlliiaasseess
       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)*



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        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 _a_l_i_a_s definition is of the form

        Alias_Type NAME = item1, item2, ...

       where _A_l_i_a_s___T_y_p_e 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 mmuusstt 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 _a_l_i_a_s member
       follow.

        User_List ::= User |
                      User ',' User_List

        User ::= '!'* username |
                 '!'* '%'group |
                 '!'* '+'netgroup |
                 '!'* User_Alias

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

        Runas_List ::= Runas_User |
                       Runas_User ',' Runas_List

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

       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



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       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, ssuuddoo will query
       each of the local host's network interfaces and, if the
       network number corresponds to one of the hosts's network
       interfaces, the corresponding netmask will be used.  The
       netmask may be specified either in standard IP address
       notation (e.g. 255.255.255.0 or ffff:ffff:ffff:ffff::), or
       CIDR notation (number of bits, e.g. 24 or 64).  A 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 _f_q_d_n 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 commandname 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
       wwiitthhoouutt 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



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       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 ssuuddoo with the
       --ee option (or as ssuuddooeeddiitt).  It may take command line
       arguments just as a normal command does.

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

        Default_Type ::= 'Defaults' |
                         'Defaults' '@' Host_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 ffllaaggss, iinntteeggeerr values, ssttrriinnggss, or
       lliissttss.  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.

   UUsseerr SSppeecciiffiiccaattiioonn
        User_Spec ::= User_List Host_List '=' Cmnd_Spec_List \
                      (':' Host_List '=' Cmnd_Spec_List)*



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        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 uusseerr ssppeecciiffiiccaattiioonn determines which commands a user may
       run (and as what user) on specified hosts.  By default,
       commands are run as rroooott, but this can be changed on a
       per-command basis.

       Let's break that down into its constituent parts:

   RRuunnaass__SSppeecc
       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 rroooott 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 ddggbb may run _/_b_i_n_/_l_s, _/_b_i_n_/_k_i_l_l, and _/_u_s_r_/_b_i_n_/_l_p_r_m
       -- but only as ooppeerraattoorr.  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 ddggbb is now allowed to run _/_b_i_n_/_l_s as ooppeerraattoorr,
       but  _/_b_i_n_/_k_i_l_l and _/_u_s_r_/_b_i_n_/_l_p_r_m as rroooott.

   TTaagg__SSppeecc
       A command may have zero or more tags associated with it.
       There are six possible tag values, 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).

       _N_O_P_A_S_S_W_D _a_n_d _P_A_S_S_W_D

       By default, ssuuddoo 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



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       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 rraayy to run _/_b_i_n_/_k_i_l_l, _/_b_i_n_/_l_s, and
       _/_u_s_r_/_b_i_n_/_l_p_r_m as rroooott on the machine rushmore without
       authenticating himself.  If we only want rraayy to be able to
       run _/_b_i_n_/_k_i_l_l 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 _e_x_e_m_p_t___g_r_o_u_p option.

       By default, if the NOPASSWD tag is applied to any of the
       entries for a user on the current host, he or she will be
       able to run sudo -l without a password.  Additionally, a
       user may only run sudo -v without a password if the
       NOPASSWD tag is present for all a user's entries that
       pertain to the current host.  This behavior may be
       overridden via the verifypw and listpw options.

       _N_O_E_X_E_C _a_n_d _E_X_E_C

       If ssuuddoo has been compiled with _n_o_e_x_e_c 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 aaaarroonn may run _/_u_s_r_/_b_i_n_/_m_o_r_e
       and _/_u_s_r_/_b_i_n_/_v_i 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.

       _S_E_T_E_N_V _a_n_d _N_O_S_E_T_E_N_V

       These tags override the value of the _s_e_t_e_n_v 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
       _e_n_v___c_h_e_c_k, _e_n_v___d_e_l_e_t_e, or _e_n_v___k_e_e_p.  As such, only trusted
       users should be allowed to set variables in this manner.
       If the command matched is AALLLL, the SETENV tag is implied
       for that command; this default may be overridden by use of
       the UNSETENV tag.

   WWiillddccaarrddss
       ssuuddoo allows shell-style _w_i_l_d_c_a_r_d_s (aka meta or glob



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       characters) to be used in hostnames, pathnames and command
       line arguments in the _s_u_d_o_e_r_s file.  Wildcard matching is
       done via the PPOOSSIIXX _g_l_o_b(3) and _f_n_m_a_t_c_h(3) routines.  Note
       that these are _n_o_t regular expressions.

       *       Matches any set of zero or more characters.

       ?       Matches any single character.

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

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

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

       Note that a forward slash ('/') will nnoott be matched by
       wildcards used in the pathname.  When matching the command
       line arguments, however, a slash ddooeess get matched by
       wildcards.  This is to make a path like:

           /usr/bin/*

       match _/_u_s_r_/_b_i_n_/_w_h_o but not _/_u_s_r_/_b_i_n_/_X_1_1_/_x_t_e_r_m.

   EExxcceeppttiioonnss ttoo wwiillddccaarrdd rruulleess
       The following exceptions apply to the above rules:

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

   OOtthheerr ssppeecciiaall cchhaarraacctteerrss aanndd rreesseerrvveedd wwoorrddss
       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 AALLLL is a built-in _a_l_i_a_s 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
       _a_l_i_a_s called AALLLL as the built-in alias will be used in
       preference to your own.  Please note that using AALLLL can be
       dangerous since in a command context, it allows the user
       to run aannyy command on the system.

       An exclamation point ('!') can be used as a logical _n_o_t
       operator both in an _a_l_i_a_s and in front of a Cmnd.  This
       allows one to exclude certain values.  Note, however, that



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

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

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

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

SSUUDDOOEERRSS OOPPTTIIOONNSS
       ssuuddoo'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.

       FFllaaggss:

       always_set_home If set, ssuuddoo will set the HOME environment
                       variable to the home directory of the
                       target user (which is root unless the --uu
                       option is used).  This effectively means
                       that the --HH option is always implied.
                       This flag is _o_f_f 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 _o_n by default.

       env_editor      If set, vviissuuddoo will use the value of the
                       EDITOR or VISUAL environment variables
                       before falling back on the default editor
                       list.  Note that this may create a
                       security hole as it allows the user to run
                       any arbitrary command as root without
                       logging.  A safer alternative is to place
                       a colon-separated list of editors in the
                       editor variable.  vviissuuddoo will then only
                       use the EDITOR or VISUAL if they match a
                       value specified in editor.  This flag is
                       _o_f_f by default.

       env_reset       If set, ssuuddoo 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



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                       then added.  The default contents of the
                       env_keep and env_check lists are displayed
                       when ssuuddoo is run by root with the _-_V
                       option.  If ssuuddoo was compiled with the
                       SECURE_PATH option, its value will be used
                       for the PATH environment variable.  This
                       flag is _o_n by default.

       fqdn            Set this flag if you want to put fully
                       qualified hostnames in the _s_u_d_o_e_r_s 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 _f_q_d_n
                       requires ssuuddoo to make DNS lookups which
                       may make ssuuddoo unusable if DNS stops
                       working (for example if the machine is not
                       plugged into the network).  Also note that
                       you must use the host's official name as
                       DNS knows it.  That is, you may not use a
                       host alias (CNAME entry) due to
                       performance issues and the fact that there
                       is no way to get all aliases from DNS.  If
                       your machine's hostname (as returned by
                       the hostname command) is already fully
                       qualified you shouldn't need to set _f_q_d_n.
                       This flag is _o_f_f by default.

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

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

       insults         If set, ssuuddoo will insult users when they



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                       enter an incorrect password.  This flag is
                       _o_f_f by default.

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

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

       long_otp_prompt When validating with a One Time Password
                       (OPT) scheme such as SS//KKeeyy or OOPPIIEE, 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 _o_f_f by default.

       mail_always     Send mail to the _m_a_i_l_t_o user every time a
                       users runs ssuuddoo.  This flag is _o_f_f by
                       default.

       mail_badpass    Send mail to the _m_a_i_l_t_o user if the user
                       running ssuuddoo does not enter the correct
                       password.  This flag is _o_f_f by default.

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

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

       mail_no_user    If set, mail will be sent to the _m_a_i_l_t_o
                       user if the invoking user is not in the
                       _s_u_d_o_e_r_s file.  This flag is _o_n by default.

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

       path_info       Normally, ssuuddoo will tell the user when a
                       command could not be found in their PATH



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                       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, ssuuddoo will tell the user that
                       they are not allowed to run it, which can
                       be confusing.  This flag is _o_n by default.

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

       preserve_groups By default ssuuddoo will initialize the group
                       vector to the list of groups the target
                       user is in.  When _p_r_e_s_e_r_v_e___g_r_o_u_p_s 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 _o_f_f by default.

       requiretty      If set, ssuuddoo will only run when the user
                       is logged in to a real tty.  This will
                       disallow things like "rsh somehost sudo
                       ls" since _r_s_h(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 _o_f_f by default.

       root_sudo       If set, root is allowed to run ssuuddoo too.
                       Disabling this prevents users from
                       "chaining" ssuuddoo commands to get a root
                       shell by doing something like "sudo sudo
                       /bin/sh".  Note, however, that turning off
                       _r_o_o_t___s_u_d_o will also prevent root and from
                       running ssuuddooeeddiitt.  Disabling _r_o_o_t___s_u_d_o
                       provides no real additional security; it
                       exists purely for historical reasons.
                       This flag is _o_n by default.

       rootpw          If set, ssuuddoo will prompt for the root
                       password instead of the password of the
                       invoking user.  This flag is _o_f_f by
                       default.

       runaspw         If set, ssuuddoo will prompt for the password



1.6.9p23                   June  1, 2010                       11





SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


                       of the user defined by the _r_u_n_a_s___d_e_f_a_u_l_t
                       option (defaults to root) instead of the
                       password of the invoking user.  This flag
                       is _o_f_f by default.

       set_home        If set and ssuuddoo is invoked with the --ss
                       option the HOME environment variable will
                       be set to the home directory of the target
                       user (which is root unless the --uu option
                       is used).  This effectively makes the --ss
                       option imply --HH.  This flag is _o_f_f by
                       default.

       set_logname     Normally, ssuuddoo will set the LOGNAME, USER
                       and USERNAME environment variables to the
                       name of the target user (usually root
                       unless the --uu 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
                       _e_n_v___r_e_s_e_t option has not been disabled,
                       entries in the _e_n_v___k_e_e_p list will override
                       the value of _s_e_t___l_o_g_n_a_m_e.  This flag is
                       _o_f_f by default.

       setenv          Allow the user to disable the _e_n_v___r_e_s_e_t
                       option from the command line.
                       Additionally, environment variables set
                       via the command line are not subject to
                       the restrictions imposed by _e_n_v___c_h_e_c_k,
                       _e_n_v___d_e_l_e_t_e, or _e_n_v___k_e_e_p.  As such, only
                       trusted users should be allowed to set
                       variables in this manner.  This flag is
                       _o_f_f by default.

       shell_noargs    If set and ssuuddoo is invoked with no
                       arguments it acts as if the --ss 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 _o_f_f by default.

       fast_glob       Normally, ssuuddoo uses the _g_l_o_b(3) function
                       to do shell-style globbing when matching
                       pathnames.  However, since it accesses the
                       file system, _g_l_o_b(3) can take a long time
                       to complete for some patterns, especially
                       when the pattern references a network file
                       system that is mounted on demand



1.6.9p23                   June  1, 2010                       12





SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


                       (automounted).  The _f_a_s_t___g_l_o_b option
                       causes ssuuddoo to use the _f_n_m_a_t_c_h(3)
                       function, which does not access the file
                       system to do its matching.  The
                       disadvantage of _f_a_s_t___g_l_o_b is that it is
                       unable to match relative pathnames such as
                       _._/_l_s or _._._/_b_i_n_/_l_s.  This has security
                       implications when path names that include
                       globbing characters are used with the
                       negation operator, '!', as such rules can
                       be trivially bypassed.  As such, this
                       option should not be used when _s_u_d_o_e_r_s
                       contains rules that contain negated path
                       names which include globbing characters.
                       This flag is _o_f_f by default.

       stay_setuid     Normally, when ssuuddoo 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 ssuuddoo act
                       as a setuid wrapper.  This can be useful
                       on systems that disable some potentially
                       dangerous functionality when a program is
                       run setuid.  This option is only effective
                       on systems with either the _s_e_t_r_e_u_i_d_(_) or
                       _s_e_t_r_e_s_u_i_d_(_) function.  This flag is _o_f_f by
                       default.

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

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

       umask_override  If set, ssuuddoo will set the umask as
                       specified by _s_u_d_o_e_r_s without modification.
                       This makes it possible to specify a more
                       permissive umask in _s_u_d_o_e_r_s than the
                       user's own umask and matches historical
                       behavior.  If _u_m_a_s_k___o_v_e_r_r_i_d_e is not set,
                       ssuuddoo will set the umask to be the union of



1.6.9p23                   June  1, 2010                       13





SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


                       the user's umask and what is specified in
                       _s_u_d_o_e_r_s.  This flag is _o_f_f by default.

       use_loginclass  If set, ssuuddoo will apply the defaults
                       specified for the target user's login
                       class if one exists.  Only available if
                       ssuuddoo is configured with the
                       --with-logincap option.  This flag is _o_f_f
                       by default.

       IInntteeggeerrss:

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

       IInntteeggeerrss tthhaatt ccaann bbee uusseedd iinn aa bboooolleeaann ccoonntteexxtt:

       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 ssuuddoo 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
                       ssuuddoo 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 actual
                       umask that is used will be the union of
                       the user's umask and 0022.  This
                       guarantees that ssuuddoo never lowers the
                       umask when running a command.  Note on
                       systems that use PAM, the default PAM
                       configuration may specify its own umask
                       which will override the value set in
                       _s_u_d_o_e_r_s.

       SSttrriinnggss:




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SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


       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 vviissuuddoo.  vviissuuddoo
                       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 _m_a_i_l_t_o
                       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 _e_x_e_c_v_(_), _e_x_e_c_v_e_(_) and
                       _f_e_x_e_c_v_e_(_) library functions that just
                       return an error.  This is used to
                       implement the _n_o_e_x_e_c functionality on
                       systems that support LD_PRELOAD or its
                       equivalent.  Defaults to
                       _/_u_s_r_/_l_o_c_a_l_/_l_i_b_e_x_e_c_/_s_u_d_o___n_o_e_x_e_c_._s_o.

       passprompt      The default prompt to use when asking for
                       a password; can be overridden via the --pp
                       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 _f_q_d_n 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 _r_o_o_t_p_w,
                           _t_a_r_g_e_t_p_w and _r_u_n_a_s_p_w flags in _s_u_d_o_e_r_s)

                       %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



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SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


                       The default value is Password:.

       runas_default   The default user to run commands as if the
                       --uu option is not specified on the command
                       line.  This defaults to root.  Note that
                       if _r_u_n_a_s___d_e_f_a_u_l_t is set it mmuusstt 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 ssuuddoo stores its
                       timestamp files.  The default is
                       _/_v_a_r_/_r_u_n_/_s_u_d_o.

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

       SSttrriinnggss tthhaatt ccaann bbee uusseedd iinn aa bboooolleeaann ccoonntteexxtt:

       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 password prompt.  It
                   has the following possible values:

                   always  Always lecture the user.

                   never   Never lecture the user.

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

                   If no value is specified, a value of _o_n_c_e is
                   implied.  Negating the option results in a
                   value of _n_e_v_e_r being used.  The default value
                   is _o_n_c_e.

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

       listpw      This option controls when a password will be



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SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


                   required when a user runs ssuuddoo with the --ll
                   option.  It has the following possible values:

                   all     All the user's _s_u_d_o_e_r_s 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 --ll option.

                   any     At least one of the user's _s_u_d_o_e_r_s
                           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 --ll option.

                   If no value is specified, a value of _a_n_y is
                   implied.  Negating the option results in a
                   value of _n_e_v_e_r being used.  The default value
                   is _a_n_y.

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

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

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

       mailto      Address to send warning and error mail to.
                   The address should be enclosed in double
                   quotes (") to protect against ssuuddoo
                   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 ssuuddoo with the --vv
                   option.  It has the following possible values:

                   all     All the user's _s_u_d_o_e_r_s 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 --vv option.



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SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


                   any     At least one of the user's _s_u_d_o_e_r_s
                           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 --vv option.

                   If no value is specified, a value of _a_l_l is
                   implied.  Negating the option results in a
                   value of _n_e_v_e_r being used.  The default value
                   is _a_l_l.

       LLiissttss tthhaatt ccaann bbee uusseedd iinn aa bboooolleeaann ccoonntteexxtt:

       env_check       Environment variables to be removed from
                       the user's environment if the variable's
                       value contains % or / characters.  This
                       can be used to guard against printf-style
                       format vulnerabilities in poorly-written
                       programs.  The argument may be a double-
                       quoted, space-separated list or a single
                       value without double-quotes.  The list can
                       be replaced, added to, deleted from, or
                       disabled by using the =, +=, -=, and !
                       operators respectively.  Regardless of
                       whether the env_reset option is enabled or
                       disabled, variables specified by env_check
                       will be preserved in the environment if
                       they pass the aforementioned check.  The
                       default list of environment variables to
                       check is displayed when ssuuddoo 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 ssuuddoo 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 ssuuddoo).

       env_keep        Environment variables to be preserved in
                       the user's environment when the _e_n_v___r_e_s_e_t
                       option is in effect.  This allows fine-
                       grained control over the environment
                       ssuuddoo-spawned processes will receive.  The
                       argument may be a double-quoted, space-



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SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


                       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 ssuuddoo
                       is run by root with the _-_V option.

       When logging via _s_y_s_l_o_g(3), ssuuddoo accepts the following
       values for the syslog facility (the value of the ssyysslloogg
       Parameter): aauutthhpprriivv (if your OS supports it), aauutthh,
       ddaaeemmoonn, uusseerr, llooccaall00, llooccaall11, llooccaall22, llooccaall33, llooccaall44,
       llooccaall55, llooccaall66, and llooccaall77.  The following syslog
       priorities are supported: aalleerrtt, ccrriitt, ddeebbuugg, eemmeerrgg, eerrrr,
       iinnffoo, nnoottiiccee, and wwaarrnniinngg.

FFIILLEESS
       _/_e_t_c_/_s_u_d_o_e_r_s            List of who can run what

       _/_e_t_c_/_g_r_o_u_p              Local groups file

       _/_e_t_c_/_n_e_t_g_r_o_u_p           List of network groups

EEXXAAMMPPLLEESS
       Since the _s_u_d_o_e_r_s file is parsed in a single pass, order
       is important.  In general, you should structure _s_u_d_o_e_r_s
       such that the Host_Alias, User_Alias, and Cmnd_Alias
       specifications 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 _s_u_d_o_e_r_s entries.  Admittedly, some of
       these are a bit contrived.  First, we define our _a_l_i_a_s_e_s:

        # 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




1.6.9p23                   June  1, 2010                       19





SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


        # 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 ssuuddoo to log via _s_y_s_l_o_g(3) using the _a_u_t_h facility
       in all cases.  We don't want to subject the full time
       staff to the ssuuddoo lecture, user mmiilllleerrtt 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 _S_E_R_V_E_R_S
       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 (_/_u_s_r_/_b_i_n_/_m_o_r_e, _/_u_s_r_/_b_i_n_/_p_g and _/_u_s_r_/_b_i_n_/_l_e_s_s).

        # 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 _U_s_e_r _s_p_e_c_i_f_i_c_a_t_i_o_n is the part that actually
       determines who may run what.

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

       We let rroooott and any user in group wwhheeeell run any command on
       any host as any user.

        FULLTIMERS     ALL = NOPASSWD: ALL

       Full time sysadmins (mmiilllleerrtt, mmiikkeeff, and ddoowwddyy) may run
       any command on any host without authenticating themselves.

        PARTTIMERS     ALL = ALL

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



1.6.9p23                   June  1, 2010                       20





SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


        jack           CSNETS = ALL

       The user jjaacckk may run any command on the machines in the
       _C_S_N_E_T_S 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 _C_S_N_E_T_S,
       the local machine's netmask will be used during matching.

        lisa           CUNETS = ALL

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

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

       The ooppeerraattoorr 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 _/_u_s_r_/_o_p_e_r_/_b_i_n_/.

        joe            ALL = /usr/bin/su operator

       The user jjooee may only _s_u(1) to operator.

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

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

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

       The user bboobb may run anything on the _S_P_A_R_C and _S_G_I
       machines as any user listed in the _O_P Runas_Alias (rroooott
       and ooppeerraattoorr).

        jim            +biglab = ALL

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

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

       Users in the sseeccrreettaarriieess 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 ffrreedd can run commands as any user in the _D_B



1.6.9p23                   June  1, 2010                       21





SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


       Runas_Alias (oorraaccllee or ssyybbaassee) without giving a password.

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

       On the _A_L_P_H_A machines, user jjoohhnn may su to anyone except
       root but he is not allowed to specify any options to the
       _s_u(1) command.

        jen            ALL, !SERVERS = ALL

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

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

       For any machine in the _S_E_R_V_E_R_S Host_Alias, jjiillll may run
       any commands in the directory _/_u_s_r_/_b_i_n_/ except for those
       commands belonging to the _S_U and _S_H_E_L_L_S Cmnd_Aliases.

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

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

        matt           valkyrie = KILL

       On his personal workstation, valkyrie, mmaatttt 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 _W_E_B_M_A_S_T_E_R_S User_Alias
       (will, wendy, and wim), may run any command as user www
       (which owns the web pages) or simply _s_u(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.

SSEECCUURRIITTYY NNOOTTEESS
       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 bbiillll from running the commands



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       listed in _S_U or _S_H_E_L_L_S since he can simply copy those
       commands to a different name, or use a shell escape from
       an editor or other program.  Therefore, these kind of
       restrictions should be considered advisory at best (and
       reinforced by policy).

       Furthermore, if the _f_a_s_t___g_l_o_b 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 _f_n_m_a_t_c_h(3) function cannot resolve
       relative paths.  While this is typically only an
       inconvenience for rules that grant privileges, it can
       result in a security issue for rules that subtract or
       revoke privileges.

       For example, given the following _s_u_d_o_e_r_s entry:

        john   ALL = /usr/bin/passwd [a-zA-Z0-9]*, /usr/bin/chsh [a-zA-Z0-9]*,
             /usr/bin/chfn [a-zA-Z0-9]*, !/usr/bin/* root

       User jjoohhnn can still run /usr/bin/passwd root if _f_a_s_t___g_l_o_b
       is enabled by changing to _/_u_s_r_/_b_i_n and running ./passwd
       root instead.

PPRREEVVEENNTTIINNGG SSHHEELLLL EESSCCAAPPEESS
       Once ssuuddoo 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
       ssuuddoo'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 ssuuddooeeddiitt is a
                 better solution to running editors via ssuuddoo.
                 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, ssuuddoo's _n_o_e_x_e_c
                 functionality can be used to prevent a program
                 run by ssuuddoo from executing any other programs.
                 Note, however, that this applies only to native
                 dynamically-linked executables.  Statically-
                 linked executables and foreign executables



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                 running under binary emulation are not affected.

                 To tell whether or not ssuuddoo supports _n_o_e_x_e_c, 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 ssuuddoo 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
                 _n_o_e_x_e_c will work at compile-time.  _n_o_e_x_e_c should
                 work on SunOS, Solaris, *BSD, Linux, IRIX, Tru64
                 UNIX, MacOS X, and HP-UX 11.x.  It is known nnoott
                 to work on AIX and UnixWare.  _n_o_e_x_e_c 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 _n_o_e_x_e_c 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 aaaarroonn to run _/_u_s_r_/_b_i_n_/_m_o_r_e and
                 _/_u_s_r_/_b_i_n_/_v_i with _n_o_e_x_e_c 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 _n_o_e_x_e_c 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 ssuuddooeeddiitt.

SSEEEE AALLSSOO
       _r_s_h(1), _s_u(1), _f_n_m_a_t_c_h(3), _g_l_o_b(3), _s_u_d_o(1m), _v_i_s_u_d_o(8)

CCAAVVEEAATTSS
       The _s_u_d_o_e_r_s file should aallwwaayyss be edited by the vviissuuddoo
       command which locks the file and does grammatical



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       checking. It is imperative that _s_u_d_o_e_r_s be free of syntax
       errors since ssuuddoo will not run with a syntactically
       incorrect _s_u_d_o_e_r_s file.

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

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

SSUUPPPPOORRTT
       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.

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






























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