

SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


NNAAMMEE
       sudoers - list of which users may execute what

DDEESSCCRRIIPPTTIIOONN
       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.

   QQuuiicckk gguuiiddee ttoo EEBBNNFF
       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).

   AAlliiaasseess
       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


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        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 mmuusstt 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 ::= '!'* user name |
                 '!'* '#'uid |
                 '!'* '%'group |
                 '!'* '+'netgroup |
                 '!'* '%:'nonunix_group |
                 '!'* User_Alias

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

       A user name, group, netgroup or nonunix_group may be enclosed in double
       quotes to avoid the need for escaping special characters.  Alternately,
       special characters may be specified in escaped hex mode, e.g. \x20 for
       space.

       The nonunix_group syntax depends on the underlying implementation.  For
       instance, the QAS AD backend supports the following formats:

       +o   Group in the same domain: "Group Name"

       +o   Group in any domain: "Group Name@FULLY.QUALIFIED.DOMAIN"

       +o   Group SID: "S-1-2-34-5678901234-5678901234-5678901234-567"

       Note that quotes around group names are optional.  Unquoted strings
       must use a backslash (\) to escape spaces and the '@' symbol.

        Runas_List ::= Runas_Member |
                       Runas_Member ',' Runas_List


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

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

        Host_List ::= Host |
                      Host ',' Host_List

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

       A Host_List is made up of one or more host names, IP addresses, network
       numbers, netgroups (prefixed with '+') and other aliases.  Again, the
       value of an item may be negated with the '!' operator.  If you do not
       specify a netmask along with the network number, ssuuddoo will query each
       of the local host's network interfaces and, if the network number
       corresponds to one of the hosts's network interfaces, the corresponding
       netmask will be used.  The netmask may be specified either in standard
       IP address notation (e.g. 255.255.255.0 or ffff:ffff:ffff:ffff::), or
       CIDR notation (number of bits, e.g. 24 or 64).  A host name may include
       shell-style wildcards (see the Wildcards section below), but unless the
       host name command on your machine returns the fully qualified host
       name, you'll need to use the _f_q_d_n option for wildcards to be useful.
       Note ssuuddoo only inspects actual network interfaces; this means that IP
       address 127.0.0.1 (localhost) will never match.  Also, the host name
       "localhost" will only match if that is the actual host name, which is
       usually only the case for non-networked systems.

        Cmnd_List ::= Cmnd |
                      Cmnd ',' Cmnd_List

        commandname ::= file name |
                        file name args |
                        file name '""'

        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 file name which may


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       include shell-style wildcards (see the Wildcards section below).  A
       simple file name allows the user to run the command with any arguments
       he/she wishes.  However, you may also specify command line arguments
       (including wildcards).  Alternately, you can specify "" to indicate
       that the command may only be run wwiitthhoouutt command line arguments.  A
       directory is a fully qualified path name ending in a '/'.  When you
       specify a directory in a Cmnd_List, the user will be able to run any
       file within that directory (but not in any 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 ssuuddoo with the --ee option (or as ssuuddooeeddiitt).  It
       may take command line arguments just as a normal command does.

   DDeeffaauullttss
       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, a
       specific command, or commands being run as a specific user.  Note that
       per-command entries may not include command line arguments.  If you
       need to specify arguments, define a Cmnd_Alias and reference that
       instead.

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

        Default_Entry ::= Default_Type Parameter_List

        Parameter_List ::= Parameter |
                           Parameter ',' Parameter_List

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

       Parameters may be ffllaaggss, iinntteeggeerr values, ssttrriinnggss, or lliissttss.  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.


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       Defaults entries are parsed in the following order: generic, host and
       user Defaults first, then runas Defaults and finally command defaults.

       See "SUDOERS OPTIONS" for a list of supported Defaults parameters.

   UUsseerr SSppeecciiffiiccaattiioonn
        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? SELinux_Spec? Tag_Spec* Cmnd

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

        SELinux_Spec ::= ('ROLE=role' | 'TYPE=type')

        Tag_Spec ::= ('NOPASSWD:' | 'PASSWD:' | 'NOEXEC:' | 'EXEC:' |
                      'SETENV:' | 'NOSETENV:' | 'LOG_INPUT:' | 'NOLOG_INPUT:' |
                      'LOG_OUTPUT:' | 'NOLOG_OUTPUT:')

       A uusseerr ssppeecciiffiiccaattiioonn determines which commands a user may run (and as
       what user) on specified hosts.  By default, commands are run as rroooott,
       but this can be changed on a per-command basis.

       The basic structure of a user specification is `who = where (as_whom)
       what'.  Let's break that down into its constituent parts:

   RRuunnaass__SSppeecc
       A Runas_Spec determines the user and/or the group that a command may be
       run as.  A fully-specified Runas_Spec consists of two Runas_Lists (as
       defined above) separated by a colon (':') and enclosed in a set of
       parentheses.  The first Runas_List indicates which users the command
       may be run as via ssuuddoo's --uu option.  The second defines a list of
       groups that can be specified via ssuuddoo's --gg option.  If both Runas_Lists
       are specified, the command may be run with any combination of users and
       groups listed in their respective Runas_Lists.  If only the first is
       specified, the command may be run as any user in the list but no --gg
       option may be specified.  If the first Runas_List is empty but the
       second is specified, the command may be run as the invoking user with
       the group set to any listed in the Runas_List.  If no Runas_Spec is
       specified the command may be run as rroooott and no group may be specified.

       A Runas_Spec sets the default for the commands that follow it.  What
       this means is that for the entry:

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

       The user ddggbb 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 ooppeerraattoorr.  E.g.,

        $ sudo -u operator /bin/ls.


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       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 ddggbb is now allowed to run _/_b_i_n_/_l_s as ooppeerraattoorr, but  _/_b_i_n_/_k_i_l_l
       and _/_u_s_r_/_b_i_n_/_l_p_r_m as rroooott.

       We can extend this to allow ddggbb to run /bin/ls with either the user or
       group set to ooppeerraattoorr:

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

       In the following example, user ttccmm may run commands that access a modem
       device file with the dialer group.  Note that in this example only the
       group will be set, the command still runs as user ttccmm.

        tcm    boulder = (:dialer) /usr/bin/tip, /usr/bin/cu, \
               /usr/local/bin/minicom

   SSEELLiinnuuxx__SSppeecc
       On systems with SELinux support, _s_u_d_o_e_r_s entries may optionally have an
       SELinux role and/or type associated with a command.  If a role or type
       is specified with the command it will override any default values
       specified in _s_u_d_o_e_r_s.  A role or type specified on the command line,
       however, will supercede the values in _s_u_d_o_e_r_s.

   TTaagg__SSppeecc
       A command may have zero or more tags associated with it.  There are
       eight possible tag values, NOPASSWD, PASSWD, NOEXEC, EXEC, SETENV,
       NOSETENV, LOG_INPUT, NOLOG_INPUT, LOG_OUTPUT and NOLOG_OUTPUT.  Once a
       tag is set on a Cmnd, subsequent Cmnds in the Cmnd_Spec_List, inherit
       the tag unless it is overridden by the opposite tag (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, ssuuddoo requires that a user authenticate him or herself
       before running a command.  This behavior can be modified via the
       NOPASSWD tag.  Like a Runas_Spec, the NOPASSWD tag sets a default for
       the commands that follow it in the Cmnd_Spec_List.  Conversely, the
       PASSWD tag can be used to reverse things.  For example:

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

       would allow the user rraayy 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 rroooott on the machine rushmore without authenticating himself.  If we
       only want rraayy 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


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       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 ssuuddoo 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 aaaarroonn 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 AALLLL, the SETENV tag is implied for that
       command; this default may be overridden by use of the NOSETENV tag.

       _L_O_G___I_N_P_U_T _a_n_d _N_O_L_O_G___I_N_P_U_T

       These tags override the value of the _l_o_g___i_n_p_u_t option on a per-command
       basis.  For more information, see the description of _l_o_g___i_n_p_u_t in the
       "SUDOERS OPTIONS" section below.

       _L_O_G___O_U_T_P_U_T _a_n_d _N_O_L_O_G___O_U_T_P_U_T

       These tags override the value of the _l_o_g___o_u_t_p_u_t option on a per-command
       basis.  For more information, see the description of _l_o_g___o_u_t_p_u_t in the
       "SUDOERS OPTIONS" section below.

   WWiillddccaarrddss
       ssuuddoo allows shell-style _w_i_l_d_c_a_r_d_s (aka meta or glob characters) to be
       used in host names, path names and command line arguments in the
       _s_u_d_o_e_r_s file.  Wildcard matching is done via the PPOOSSIIXX _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.


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

       [!...]  Matches any character nnoott in the specified range.

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

       POSIX character classes may also be used if your system's _g_l_o_b(3) and
       _f_n_m_a_t_c_h(3) functions support them.  However, because the ':' character
       has special meaning in _s_u_d_o_e_r_s, it must be escaped.  For example:

           /bin/ls [[\:alpha\:]]*

       Would match any file name beginning with a letter.

       Note that a forward slash ('/') will nnoott be matched by wildcards used
       in the path name.  When matching the command line arguments, however, a
       slash ddooeess 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.

   EExxcceeppttiioonnss ttoo wwiillddccaarrdd rruulleess
       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 aannyy arguments.

   IInncclluuddiinngg ootthheerr ffiilleess ffrroomm wwiitthhiinn ssuuddooeerrss
       It is possible to include other _s_u_d_o_e_r_s files from within the _s_u_d_o_e_r_s
       file currently being parsed using the #include and #includedir
       directives.

       This can be used, for example, to keep a site-wide _s_u_d_o_e_r_s file in
       addition to a local, per-machine file.  For the sake of this example
       the site-wide _s_u_d_o_e_r_s will be _/_e_t_c_/_s_u_d_o_e_r_s and the per-machine one will
       be _/_e_t_c_/_s_u_d_o_e_r_s_._l_o_c_a_l.  To include _/_e_t_c_/_s_u_d_o_e_r_s_._l_o_c_a_l from within
       _/_e_t_c_/_s_u_d_o_e_r_s we would use the following line in _/_e_t_c_/_s_u_d_o_e_r_s:

           #include /etc/sudoers.local

       When ssuuddoo reaches this line it will suspend processing of the current
       file (_/_e_t_c_/_s_u_d_o_e_r_s) and switch to _/_e_t_c_/_s_u_d_o_e_r_s_._l_o_c_a_l.  Upon reaching
       the end of _/_e_t_c_/_s_u_d_o_e_r_s_._l_o_c_a_l, the rest of _/_e_t_c_/_s_u_d_o_e_r_s will be
       processed.  Files that are included may themselves include other files.
       A hard limit of 128 nested include files is enforced to prevent include
       file loops.

       The file name may include the %h escape, signifying the short form of
       the host name.  I.e., if the machine's host name is "xerxes", then

       #include /etc/sudoers.%h


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       will cause ssuuddoo to include the file _/_e_t_c_/_s_u_d_o_e_r_s_._x_e_r_x_e_s.

       The #includedir directive can be used to create a _s_u_d_o_._d directory that
       the system package manager can drop _s_u_d_o_e_r_s rules into as part of
       package installation.  For example, given:

       #includedir /etc/sudoers.d

       ssuuddoo will read each file in _/_e_t_c_/_s_u_d_o_e_r_s_._d, skipping file names that
       end in ~ or contain a . character to avoid causing problems with
       package manager or editor temporary/backup files.  Files are parsed in
       sorted lexical order.  That is, _/_e_t_c_/_s_u_d_o_e_r_s_._d_/_0_1___f_i_r_s_t will be parsed
       before _/_e_t_c_/_s_u_d_o_e_r_s_._d_/_1_0___s_e_c_o_n_d.  Be aware that because the sorting is
       lexical, not numeric, _/_e_t_c_/_s_u_d_o_e_r_s_._d_/_1___w_h_o_o_p_s would be loaded aafftteerr
       _/_e_t_c_/_s_u_d_o_e_r_s_._d_/_1_0___s_e_c_o_n_d.  Using a consistent number of leading zeroes
       in the file names can be used to avoid such problems.

       Note that unlike files included via #include, vviissuuddoo will not edit the
       files in a #includedir directory unless one of them contains a syntax
       error.  It is still possible to run vviissuuddoo with the -f flag to edit the
       files directly.

   OOtthheerr ssppeecciiaall cchhaarraacctteerrss aanndd rreesseerrvveedd wwoorrddss
       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 AALLLL 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 AALLLL as the built-in alias will be used in
       preference to your own.  Please note that using AALLLL can be dangerous
       since in a command context, it allows the user to run aannyy 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 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 user name or host name): '@', '!', '=',
       ':', ',', '(', ')', '\'.


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SSUUDDOOEERRSS OOPPTTIIOONNSS
       ssuuddoo'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.

       BBoooolleeaann FFllaaggss:

       always_set_home If enabled, ssuuddoo will set the HOME environment variable
                       to the home directory of the target user (which is root
                       unless the --uu option is used).  This effectively means
                       that the --HH option is always implied.  Note that HOME
                       is already set when the the _e_n_v___r_e_s_e_t option is
                       enabled, so _a_l_w_a_y_s___s_e_t___h_o_m_e is only effective for
                       configurations where _e_n_v___r_e_s_e_t is disabled.  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.

       closefrom_override
                       If set, the user may use ssuuddoo's --CC option which
                       overrides the default starting point at which ssuuddoo
                       begins closing open file descriptors.  This flag is _o_f_f
                       by default.

       compress_io     If set, and ssuuddoo is configured to log a command's input
                       or output, the I/O logs will be compressed using zzlliibb.
                       This flag is _o_n by default when ssuuddoo is compiled with
                       zzlliibb support.

       env_editor      If set, vviissuuddoo 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.  vviissuuddoo 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, ssuuddoo will reset the environment to only contain
                       the LOGNAME, MAIL, 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 displayed when ssuuddoo is run by root
                       with the _-_V option.  If the _s_e_c_u_r_e___p_a_t_h option is set,
                       its value will be used for the PATH environment
                       variable.  This flag is _o_n by default.

       fast_glob       Normally, ssuuddoo uses the _g_l_o_b(3) function to do shell-


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                       style globbing when matching path names.  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 (automounted).  The _f_a_s_t___g_l_o_b
                       option causes ssuuddoo 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 path names 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.

       fqdn            Set this flag if you want to put fully qualified host
                       names 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 ssuuddoo to make DNS lookups
                       which may make ssuuddoo 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 host name (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, ssuuddoo will ignore '.' or '' (current dir) in the
                       PATH environment variable; the PATH itself is not
                       modified.  This flag is _o_f_f by default.

       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 ssuuddoo 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, ssuuddoo will insult users when they enter an
                       incorrect password.  This flag is _o_f_f by default.

       log_host        If set, the host name will be logged in the (non-


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                       syslog) ssuuddoo 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) ssuuddoo log file.  This flag is _o_f_f by default.

       long_otp_prompt When validating with a One Time Password (OPT) scheme
                       such as SS//KKeeyy or OOPPIIEE, 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
                       ssuuddoo.  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 ssuuddoo
                       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 ssuuddoo 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 ssuuddoo 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, ssuuddoo 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, ssuuddoo 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:".


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                       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, ssuuddoo 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.

       pwfeedback      By default, ssuuddoo reads the password like most other
                       Unix programs, by turning off echo until the user hits
                       the return (or enter) key.  Some users become confused
                       by this as it appears to them that ssuuddoo has hung at
                       this point.  When _p_w_f_e_e_d_b_a_c_k is set, ssuuddoo will provide
                       visual feedback when the user presses a key.  Note that
                       this does have a security impact as an onlooker may be
                       able to determine the length of the password being
                       entered.  This flag is _o_f_f by default.

       requiretty      If set, ssuuddoo will only run when the user is logged in
                       to a real tty.  When this flag is set, ssuuddoo can only be
                       run from a login session and not via other means such
                       as _c_r_o_n(1m) or cgi-bin scripts.  This flag is _o_f_f by
                       default.

       root_sudo       If set, root is allowed to run ssuuddoo too.  Disabling
                       this prevents users from "chaining" ssuuddoo 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 from running ssuuddooeeddiitt.
                       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, ssuuddoo 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, ssuuddoo will prompt for the password 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 enabled and ssuuddoo is invoked with the --ss option the
                       HOME environment variable will be set to the home
                       directory of the target user (which is root unless the
                       --uu option is used).  This effectively makes the --ss
                       option imply --HH.  Note that HOME is already set when
                       the the _e_n_v___r_e_s_e_t option is enabled, so _s_e_t___h_o_m_e is
                       only effective for configurations where _e_n_v___r_e_s_e_t is
                       disabled.  This flag is _o_f_f by default.

       set_logname     Normally, ssuuddoo will set the LOGNAME, USER and USERNAME


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                       environment variables to the name of the target user
                       (usually root unless the --uu option is given).  However,
                       since some programs (including the RCS revision control
                       system) use LOGNAME to determine the real identity of
                       the user, it may be desirable to change this behavior.
                       This can be done by negating the set_logname option.
                       Note that if the _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_n 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 ssuuddoo is invoked with no arguments it acts as
                       if the --ss option had been given.  That is, it runs a
                       shell as root (the shell is determined by the SHELL
                       environment variable if it is set, falling back on the
                       shell listed in the invoking user's /etc/passwd entry
                       if not).  This flag is _o_f_f by default.

       stay_setuid     Normally, when ssuuddoo 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 ssuuddoo 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, ssuuddoo will prompt for the password of the user
                       specified by the --uu option (defaults to root) instead
                       of the password of the invoking user.  In addition, the
                       timestamp file name will include the target user's
                       name.  Note that this flag precludes the use of a uid
                       not listed in the passwd database as an argument to the
                       --uu option.  This flag is _o_f_f by default.

       log_input       If set, ssuuddoo will run the command in a _p_s_e_u_d_o _t_t_y and
                       log all user input.  If the standard input is not
                       connected to the user's tty, due to I/O redirection or
                       because the command is part of a pipeline, that input
                       is also captured and stored in a separate log file.

                       Input is logged to the _/_v_a_r_/_l_o_g_/_s_u_d_o_-_i_o directory using
                       a unique session ID that is included in the normal ssuuddoo
                       log line, prefixed with _T_S_I_D_=.


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       log_output      If set, ssuuddoo will run the command in a _p_s_e_u_d_o _t_t_y and
                       log all output that is sent to the screen, similar to
                       the _s_c_r_i_p_t(1) command.  If the standard output or
                       standard error is not connected to the user's tty, due
                       to I/O redirection or because the command is part of a
                       pipeline, that output is also captured and stored in
                       separate log files.

                       Output is logged to the _/_v_a_r_/_l_o_g_/_s_u_d_o_-_i_o directory
                       using a unique session ID that is included in the
                       normal ssuuddoo log line, prefixed with _T_S_I_D_=.

                       Output logs may be viewed with the _s_u_d_o_r_e_p_l_a_y(1m)
                       utility, which can also be used to list or search the
                       available logs.

       tty_tickets     If set, users must authenticate on a per-tty basis.
                       With this flag enabled, ssuuddoo will use a file named for
                       the tty the user is logged in on in the user's time
                       stamp directory.  If disabled, the time stamp of the
                       directory is used instead.  This flag is _o_n by default.

       umask_override  If set, ssuuddoo 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, ssuuddoo will set the umask to
                       be the union of 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, ssuuddoo will apply the defaults specified for the
                       target user's login class if one exists.  Only
                       available if ssuuddoo is configured with the
                       --with-logincap option.  This flag is _o_f_f by default.

       use_pty         If set, ssuuddoo will run the command in a pseudo-pty even
                       if no I/O logging is being gone.  A malicious program
                       run under ssuuddoo could conceivably fork a background
                       process that retains to the user's terminal device
                       after the main program has finished executing.  Use of
                       this option will make that impossible.

       visiblepw       By default, ssuuddoo will refuse to run if the user must
                       enter a password but it is not possible to disable echo
                       on the terminal.  If the _v_i_s_i_b_l_e_p_w flag is set, ssuuddoo
                       will prompt for a password even when it would be
                       visible on the screen.  This makes it possible to run
                       things like "rsh somehost sudo ls" since _r_s_h(1) does
                       not allocate a tty.  This flag is _o_f_f by default.

       IInntteeggeerrss:

       closefrom       Before it executes a command, ssuuddoo will close all open
                       file descriptors other than standard input, standard


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                       output and standard error (ie: file descriptors 0-2).
                       The _c_l_o_s_e_f_r_o_m option can be used to specify a different
                       file descriptor at which to start closing.  The default
                       is 3.

       passwd_tries    The number of tries a user gets to enter his/her
                       password before ssuuddoo logs the failure and exits.  The
                       default is 3.

       IInntteeggeerrss tthhaatt ccaann bbee uusseedd iinn aa bboooolleeaann ccoonntteexxtt:

       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 ssuuddoo password prompt times
                       out, or 0 for no timeout.  The timeout may include a
                       fractional component if minute granularity is
                       insufficient, for example 2.5.  The default is 5.

       timestamp_timeout
                       Number of minutes that can elapse before ssuuddoo will ask
                       for a passwd again.  The timeout may include a
                       fractional component if minute granularity is
                       insufficient, for example 2.5.  The default is 5.  Set
                       this to 0 to always prompt for a password.  If set to a
                       value less than 0 the user's 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 ssuuddoo 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.

       SSttrriinnggss:

       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 vviissuuddoo.  vviissuuddoo 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 "vi".


1.7.4                     July 21, 2010                        16


SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


       mailsub         Subject of the mail sent to the _m_a_i_l_t_o user. The escape
                       %h will expand to the host name 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 --pp option or the SUDO_PROMPT
                       environment variable.  The following percent (`%')
                       escapes are supported:

                       %H  expanded to the local host name including the
                           domain name (on if the machine's host name is fully
                           qualified or the _f_q_d_n option is set)

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

                       %p  expanded to the user whose password is being asked
                           for (respects the _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

                       The default value is Password:.

       role            The default SELinux role to use when constructing a new
                       security context to run the command.  The default role
                       may be overridden on a per-command basis in _s_u_d_o_e_r_s or
                       via command line options.  This option is only
                       available whe ssuuddoo is built with SELinux support.

       runas_default   The default user to run commands as if the --uu 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 mmuusstt 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.


1.7.4                     July 21, 2010                        17


SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


       sudoers_locale  Locale to use when parsing the sudoers file.  Note that
                       changing the locale may affect how sudoers is
                       interpreted.  Defaults to "C".

       timestampdir    The directory in which ssuuddoo stores its timestamp files.
                       The default is _/_v_a_r_/_a_d_m_/_s_u_d_o.

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

       type            The default SELinux type to use when constructing a new
                       security context to run the command.  The default type
                       may be overridden on a per-command basis in _s_u_d_o_e_r_s or
                       via command line options.  This option is only
                       available whe ssuuddoo is built with SELinux support.

       SSttrriinnggss tthhaatt ccaann bbee uusseedd iinn aa bboooolleeaann ccoonntteexxtt:

       askpass     The _a_s_k_p_a_s_s option specifies the fully qualified path to a
                   helper program used to read the user's password when no
                   terminal is available.  This may be the case when ssuuddoo is
                   executed from a graphical (as opposed to text-based)
                   application.  The program specified by _a_s_k_p_a_s_s should
                   display the argument passed to it as the prompt and write
                   the user's password to the standard output.  The value of
                   _a_s_k_p_a_s_s may be overridden by the SUDO_ASKPASS environment
                   variable.

       env_file    The _e_n_v___f_i_l_e options specifies the fully qualified path to
                   a file containing variables to be set in the environment of
                   the program being run.  Entries in this file should either
                   be of the form VARIABLE=value or export VARIABLE=value.
                   The value may optionally be surrounded by single or double
                   quotes.  Variables in this file are subject to other ssuuddoo
                   environment settings such as _e_n_v___k_e_e_p and _e_n_v___c_h_e_c_k.

       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 ssuuddoo.

                   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.


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SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


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

       listpw      This option controls when a password will be required when
                   a user runs ssuuddoo with the --ll 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 --ll
                           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 --ll
                           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 ssuuddoo log file (not the syslog log file).
                   Setting a path turns on logging to a file; negating this
                   option turns it off.  By default, ssuuddoo logs via syslog.

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

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

       mailfrom    Address to use for the "from" address when sending warning
                   and error mail.  The address should be enclosed in double
                   quotes (") to protect against ssuuddoo interpreting the @ sign.
                   Defaults to the name of the user running ssuuddoo.

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

       secure_path Path used for every command run from ssuuddoo.  If you don't
                   trust the people running ssuuddoo to have a sane PATH
                   environment variable you may want to use this.  Another use
                   is if you want to have the "root path" be separate from the
                   "user path."  Users in the group specified by the
                   _e_x_e_m_p_t___g_r_o_u_p option are not affected by _s_e_c_u_r_e___p_a_t_h.  This
                   option is not set by default.

       syslog      Syslog facility if syslog is being used for logging (negate


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SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


                   to disable syslog logging).  Defaults to auth.

       verifypw    This option controls when a password will be required when
                   a user runs ssuuddoo with the --vv 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 --vv
                           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 --vv
                           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.

       LLiissttss tthhaatt ccaann bbee uusseedd iinn aa bboooolleeaann ccoonntteexxtt:

       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 ssuuddoo
                       is run by root with the _-_V option.

       env_delete      Environment variables to be removed from the user's
                       environment when the _e_n_v___r_e_s_e_t option is not in effect.
                       The argument may be a double-quoted, space-separated
                       list or a single value without double-quotes.  The list
                       can be replaced, added to, deleted from, or disabled by
                       using the =, +=, -=, and ! operators respectively.  The
                       default list of environment variables to remove is
                       displayed when ssuuddoo 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 ssuuddoo).

       env_keep        Environment variables to be preserved in the user's


1.7.4                     July 21, 2010                        20


SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


                       environment when the _e_n_v___r_e_s_e_t option is in effect.
                       This allows fine-grained control over the environment
                       ssuuddoo-spawned processes will receive.  The argument may
                       be a double-quoted, space-separated list or a single
                       value without double-quotes.  The list can be replaced,
                       added to, deleted from, or disabled by using the =, +=,
                       -=, and ! operators respectively.  The default list of
                       variables to keep is displayed when ssuuddoo is run by root
                       with the _-_V option.

       When logging via _s_y_s_l_o_g(3), ssuuddoo accepts the following values for the
       syslog facility (the value of the ssyysslloogg Parameter): aauutthhpprriivv (if your
       OS supports it), aauutthh, ddaaeemmoonn, uusseerr, llooccaall00, llooccaall11, llooccaall22, llooccaall33,
       llooccaall44, llooccaall55, llooccaall66, and llooccaall77.  The following syslog priorities
       are supported: aalleerrtt, ccrriitt, ddeebbuugg, eemmeerrgg, eerrrr, iinnffoo, nnoottiiccee, and
       wwaarrnniinngg.

FFIILLEESS
       _/_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

       _/_v_a_r_/_l_o_g_/_s_u_d_o_-_i_o        I/O log files

EEXXAAMMPPLLEESS
       Below are example _s_u_d_o_e_r_s entries.  Admittedly, some of these are a bit
       contrived.  First, we allow a few environment variables to pass and
       then define our _a_l_i_a_s_e_s:

        # Run X applications through sudo; HOME is used to find the
        # .Xauthority file.  Note that other programs use HOME to find
        # configuration files and this may lead to privilege escalation!
        Defaults env_keep += "DISPLAY HOME"

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

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

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


1.7.4                     July 21, 2010                        21


SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


        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 ssuuddoo
       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 ssuuddoo lecture, user mmiilllleerrtt
       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 rroooott and any user in group wwhheeeell run any command on any host as
       any user.

        FULLTIMERS     ALL = NOPASSWD: ALL

       Full time sysadmins (mmiilllleerrtt, mmiikkeeff, and ddoowwddyy) may run any command on
       any host without authenticating themselves.

        PARTTIMERS     ALL = ALL

       Part time sysadmins (bboossttlleeyy, jjwwffooxx, and ccrraawwll) may run any command on
       any host but they must authenticate themselves first (since the entry
       lacks the NOPASSWD tag).


1.7.4                     July 21, 2010                        22


SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


        jack           CSNETS = ALL

       The user jjaacckk 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 lliissaa 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 ooppeerraattoorr 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 jjooee may only _s_u(1) to operator.

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

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

       Users in the ooppeerrss group may run commands in _/_u_s_r_/_s_b_i_n_/ as themselves
       with any group in the _A_D_M_I_N_G_R_P Runas_Alias (the aaddmm and ooppeerr groups).

       The user ppeettee 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 user names on the command line.

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

       The user bboobb 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 (rroooott and ooppeerraattoorr).

        jim            +biglab = ALL

       The user jjiimm may run any command on machines in the _b_i_g_l_a_b netgroup.
       ssuuddoo knows that "biglab" is a netgroup due to the '+' prefix.

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

       Users in the sseeccrreettaarriieess 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


1.7.4                     July 21, 2010                        23


SUDOERS(4)             MAINTENANCE COMMANDS            SUDOERS(4)


       The user ffrreedd can run commands as any user in the _D_B Runas_Alias
       (oorraaccllee or ssyybbaassee) without giving a password.

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

       On the _A_L_P_H_A machines, user jjoohhnn 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 jjeenn 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, jjiillll 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 sstteevvee may run any command in the directory
       /usr/local/op_commands/ but only as user operator.

        matt           valkyrie = KILL

       On his personal workstation, valkyrie, mmaatttt 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.

SSEECCUURRIITTYY NNOOTTEESS
       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 bbiillll from running the commands 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


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       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 jjoohhnn 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.

PPRREEVVEENNTTIINNGG SSHHEELLLL EESSCCAAPPEESS
       Once ssuuddoo 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 ssuuddoo'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 ssuuddooeeddiitt is a better
                 solution to running editors via ssuuddoo.  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, ssuuddoo's _n_o_e_x_e_c functionality
                 can be used to prevent a program run by ssuuddoo from executing
                 any other programs.  Note, however, that this applies only to
                 native dynamically-linked executables.  Statically-linked
                 executables and foreign executables running under binary
                 emulation are not affected.

                 To tell whether or not ssuuddoo 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:


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                 then ssuuddoo 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 nnoott 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 aaaarroonn 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 ssuuddooeeddiitt.

SSEEEE AALLSSOO
       _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)

CCAAVVEEAATTSS
       The _s_u_d_o_e_r_s file should aallwwaayyss be edited by the vviissuuddoo command which
       locks the file and does grammatical checking. It is imperative that
       _s_u_d_o_e_r_s be free of syntax errors since ssuuddoo 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 host name in the netgroup (as is usually the case), you
       either need to have the machine's host name be fully qualified as
       returned by the hostname command or use the _f_q_d_n option in _s_u_d_o_e_r_s.

BBUUGGSS
       If you feel you have found a bug in ssuuddoo, please submit a bug report at
       http://www.sudo.ws/sudo/bugs/

SSUUPPPPOORRTT
       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.


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DDIISSCCLLAAIIMMEERR
       ssuuddoo 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 ssuuddoo or
       http://www.sudo.ws/sudo/license.html for complete details.


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