1 Copyright (c) 1994-1996, 1998-2005, 2007-2008
2 Todd C. Miller <Todd.Miller@courtesan.com>
4 Permission to use, copy, modify, and distribute this software for any
5 purpose with or without fee is hereby granted, provided that the above
6 copyright notice and this permission notice appear in all copies.
8 THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
17 Sponsored in part by the Defense Advanced Research Projects
18 Agency (DARPA) and Air Force Research Laboratory, Air Force
19 Materiel Command, USAF, under agreement number F39502-99-1-0512.
21 $Sudo: sudoers.pod,v 1.155 2008/12/03 20:57:13 millert Exp $
26 sudoers - list of which users may execute what
30 The I<sudoers> file is composed of two types of entries: aliases
31 (basically variables) and user specifications (which specify who
34 When multiple entries match for a user, they are applied in order.
35 Where there are multiple matches, the last match is used (which is
36 not necessarily the most specific match).
38 The I<sudoers> grammar will be described below in Extended Backus-Naur
39 Form (EBNF). Don't despair if you don't know what EBNF is; it is
40 fairly simple, and the definitions below are annotated.
42 =head2 Quick guide to EBNF
44 EBNF is a concise and exact way of describing the grammar of a language.
45 Each EBNF definition is made up of I<production rules>. E.g.,
47 symbol ::= definition | alternate1 | alternate2 ...
49 Each I<production rule> references others and thus makes up a
50 grammar for the language. EBNF also contains the following
51 operators, which many readers will recognize from regular
52 expressions. Do not, however, confuse them with "wildcard"
53 characters, which have different meanings.
59 Means that the preceding symbol (or group of symbols) is optional.
60 That is, it may appear once or not at all.
64 Means that the preceding symbol (or group of symbols) may appear
69 Means that the preceding symbol (or group of symbols) may appear
74 Parentheses may be used to group symbols together. For clarity,
75 we will use single quotes ('') to designate what is a verbatim character
76 string (as opposed to a symbol name).
80 There are four kinds of aliases: C<User_Alias>, C<Runas_Alias>,
81 C<Host_Alias> and C<Cmnd_Alias>.
83 Alias ::= 'User_Alias' User_Alias (':' User_Alias)* |
84 'Runas_Alias' Runas_Alias (':' Runas_Alias)* |
85 'Host_Alias' Host_Alias (':' Host_Alias)* |
86 'Cmnd_Alias' Cmnd_Alias (':' Cmnd_Alias)*
88 User_Alias ::= NAME '=' User_List
90 Runas_Alias ::= NAME '=' Runas_List
92 Host_Alias ::= NAME '=' Host_List
94 Cmnd_Alias ::= NAME '=' Cmnd_List
96 NAME ::= [A-Z]([a-z][A-Z][0-9]_)*
98 Each I<alias> definition is of the form
100 Alias_Type NAME = item1, item2, ...
102 where I<Alias_Type> is one of C<User_Alias>, C<Runas_Alias>, C<Host_Alias>,
103 or C<Cmnd_Alias>. A C<NAME> is a string of uppercase letters, numbers,
104 and underscore characters ('_'). A C<NAME> B<must> start with an
105 uppercase letter. It is possible to put several alias definitions
106 of the same type on a single line, joined by a colon (':'). E.g.,
108 Alias_Type NAME = item1, item2, item3 : NAME = item4, item5
110 The definitions of what constitutes a valid I<alias> member follow.
115 User ::= '!'* username |
121 A C<User_List> is made up of one or more usernames, uids (prefixed
122 with '#'), system groups (prefixed with '%'), netgroups (prefixed
123 with '+') and C<User_Alias>es. Each list item may be prefixed with
124 zero or more '!' operators. An odd number of '!' operators negate
125 the value of the item; an even number just cancel each other out.
127 Runas_List ::= Runas_Member |
128 Runas_Member ',' Runas_List
130 Runas_Member ::= '!'* username |
136 A C<Runas_List> is similar to a C<User_List> except that instead
137 of C<User_Alias>es it can contain C<Runas_Alias>es. Note that
138 usernames and groups are matched as strings. In other words, two
139 users (groups) with the same uid (gid) are considered to be distinct.
140 If you wish to match all usernames with the same uid (e.g.E<nbsp>root
141 and toor), you can use a uid instead (#0 in the example given).
146 Host ::= '!'* hostname |
148 '!'* network(/netmask)? |
152 A C<Host_List> is made up of one or more hostnames, IP addresses,
153 network numbers, netgroups (prefixed with '+') and other aliases.
154 Again, the value of an item may be negated with the '!' operator.
155 If you do not specify a netmask along with the network number,
156 B<sudo> will query each of the local host's network interfaces and,
157 if the network number corresponds to one of the hosts's network
158 interfaces, the corresponding netmask will be used. The netmask
159 may be specified either in standard IP address notation
160 (e.g.E<nbsp>255.255.255.0 or ffff:ffff:ffff:ffff::),
161 or CIDR notation (number of bits, e.g.E<nbsp>24 or 64). A hostname may
162 include shell-style wildcards (see the L<Wildcards> section below),
163 but unless the C<hostname> command on your machine returns the fully
164 qualified hostname, you'll need to use the I<fqdn> option for
165 wildcards to be useful.
170 commandname ::= filename |
174 Cmnd ::= '!'* commandname |
179 A C<Cmnd_List> is a list of one or more commandnames, directories, and other
180 aliases. A commandname is a fully qualified filename which may include
181 shell-style wildcards (see the L<Wildcards> section below). A simple
182 filename allows the user to run the command with any arguments he/she
183 wishes. However, you may also specify command line arguments (including
184 wildcards). Alternately, you can specify C<""> to indicate that the command
185 may only be run B<without> command line arguments. A directory is a
186 fully qualified pathname ending in a '/'. When you specify a directory
187 in a C<Cmnd_List>, the user will be able to run any file within that directory
188 (but not in any subdirectories therein).
190 If a C<Cmnd> has associated command line arguments, then the arguments
191 in the C<Cmnd> must match exactly those given by the user on the command line
192 (or match the wildcards if there are any). Note that the following
193 characters must be escaped with a '\' if they are used in command
194 arguments: ',', ':', '=', '\'. The special command C<"sudoedit">
195 is used to permit a user to run B<sudo> with the B<-e> option (or
196 as B<sudoedit>). It may take command line arguments just as
197 a normal command does.
201 Certain configuration options may be changed from their default
202 values at runtime via one or more C<Default_Entry> lines. These
203 may affect all users on any host, all users on a specific host, a
204 specific user, a specific command, or commands being run as a specific user.
205 Note that per-command entries may not include command line arguments.
206 If you need to specify arguments, define a C<Cmnd_Alias> and reference
209 Default_Type ::= 'Defaults' |
210 'Defaults' '@' Host_List |
211 'Defaults' ':' User_List |
212 'Defaults' '!' Cmnd_List |
213 'Defaults' '>' Runas_List
215 Default_Entry ::= Default_Type Parameter_List
217 Parameter_List ::= Parameter |
218 Parameter ',' Parameter_List
220 Parameter ::= Parameter '=' Value |
221 Parameter '+=' Value |
222 Parameter '-=' Value |
225 Parameters may be B<flags>, B<integer> values, B<strings>, or B<lists>.
226 Flags are implicitly boolean and can be turned off via the '!'
227 operator. Some integer, string and list parameters may also be
228 used in a boolean context to disable them. Values may be enclosed
229 in double quotes (C<">) when they contain multiple words. Special
230 characters may be escaped with a backslash (C<\>).
232 Lists have two additional assignment operators, C<+=> and C<-=>.
233 These operators are used to add to and delete from a list respectively.
234 It is not an error to use the C<-=> operator to remove an element
235 that does not exist in a list.
237 Defaults entries are parsed in the following order: generic, host
238 and user Defaults first, then runas Defaults and finally command
241 See L</"SUDOERS OPTIONS"> for a list of supported Defaults parameters.
243 =head2 User Specification
245 User_Spec ::= User_List Host_List '=' Cmnd_Spec_List \
246 (':' Host_List '=' Cmnd_Spec_List)*
248 Cmnd_Spec_List ::= Cmnd_Spec |
249 Cmnd_Spec ',' Cmnd_Spec_List
251 Cmnd_Spec ::= Runas_Spec? Tag_Spec* Cmnd
253 Runas_Spec ::= '(' Runas_List? (: Runas_List)? ')'
255 Tag_Spec ::= ('NOPASSWD:' | 'PASSWD:' | 'NOEXEC:' | 'EXEC:' |
256 'SETENV:' | 'NOSETENV:' )
258 A B<user specification> determines which commands a user may run
259 (and as what user) on specified hosts. By default, commands are
260 run as B<root>, but this can be changed on a per-command basis.
262 Let's break that down into its constituent parts:
266 A C<Runas_Spec> determines the user and/or the group that a command
267 may be run as. A fully-specified C<Runas_Spec> consists of two
268 C<Runas_List>s (as defined above) separated by a colon (':') and
269 enclosed in a set of parentheses. The first C<Runas_List> indicates
270 which users the command may be run as via B<sudo>'s B<-u> option.
271 The second defines a list of groups that can be specified via
272 B<sudo>'s B<-g> option. If both C<Runas_List>s are specified, the
273 command may be run with any combination of users and groups listed
274 in their respective C<Runas_List>s. If only the first is specified,
275 the command may be run as any user in the list but no B<-g> option
276 may be specified. If the first C<Runas_List> is empty but the
277 second is specified, the command may be run as the invoking user
278 with the group set to any listed in the C<Runas_List>. If no
279 C<Runas_Spec> is specified the command may be run as B<root> and
280 no group may be specified.
282 A C<Runas_Spec> sets the default for the commands that follow it.
283 What this means is that for the entry:
285 dgb boulder = (operator) /bin/ls, /bin/kill, /usr/bin/lprm
287 The user B<dgb> may run F</bin/ls>, F</bin/kill>, and
288 F</usr/bin/lprm> -- but only as B<operator>. E.g.,
290 $ sudo -u operator /bin/ls.
292 It is also possible to override a C<Runas_Spec> later on in an
293 entry. If we modify the entry like so:
295 dgb boulder = (operator) /bin/ls, (root) /bin/kill, /usr/bin/lprm
297 Then user B<dgb> is now allowed to run F</bin/ls> as B<operator>,
298 but F</bin/kill> and F</usr/bin/lprm> as B<root>.
300 We can extend this to allow B<dgb> to run C</bin/ls> with either
301 the user or group set to B<operator>:
303 dgb boulder = (operator : operator) /bin/ls, (root) /bin/kill, \
306 In the following example, user B<tcm> may run commands that access
307 a modem device file with the dialer group. Note that in this example
308 only the group will be set, the command still runs as user B<tcm>.
310 tcm boulder = (:dialer) /usr/bin/tip, /usr/bin/cu, \
311 /usr/local/bin/minicom
315 A command may have zero or more tags associated with it. There are
316 eight possible tag values, C<NOPASSWD>, C<PASSWD>, C<NOEXEC>, C<EXEC>,
317 C<SETENV> and C<NOSETENV>.
318 Once a tag is set on a C<Cmnd>, subsequent C<Cmnd>s in the
319 C<Cmnd_Spec_List>, inherit the tag unless it is overridden by the
320 opposite tag (i.e.: C<PASSWD> overrides C<NOPASSWD> and C<NOEXEC>
323 =head3 NOPASSWD and PASSWD
325 By default, B<sudo> requires that a user authenticate him or herself
326 before running a command. This behavior can be modified via the
327 C<NOPASSWD> tag. Like a C<Runas_Spec>, the C<NOPASSWD> tag sets
328 a default for the commands that follow it in the C<Cmnd_Spec_List>.
329 Conversely, the C<PASSWD> tag can be used to reverse things.
332 ray rushmore = NOPASSWD: /bin/kill, /bin/ls, /usr/bin/lprm
334 would allow the user B<ray> to run F</bin/kill>, F</bin/ls>, and
335 F</usr/bin/lprm> as B<root> on the machine rushmore without
336 authenticating himself. If we only want B<ray> to be able to
337 run F</bin/kill> without a password the entry would be:
339 ray rushmore = NOPASSWD: /bin/kill, PASSWD: /bin/ls, /usr/bin/lprm
341 Note, however, that the C<PASSWD> tag has no effect on users who are
342 in the group specified by the I<exempt_group> option.
344 By default, if the C<NOPASSWD> tag is applied to any of the entries
345 for a user on the current host, he or she will be able to run
346 C<sudo -l> without a password. Additionally, a user may only run
347 C<sudo -v> without a password if the C<NOPASSWD> tag is present
348 for all a user's entries that pertain to the current host.
349 This behavior may be overridden via the verifypw and listpw options.
351 =head3 NOEXEC and EXEC
353 If B<sudo> has been compiled with I<noexec> support and the underlying
354 operating system supports it, the C<NOEXEC> tag can be used to prevent
355 a dynamically-linked executable from running further commands itself.
357 In the following example, user B<aaron> may run F</usr/bin/more>
358 and F</usr/bin/vi> but shell escapes will be disabled.
360 aaron shanty = NOEXEC: /usr/bin/more, /usr/bin/vi
362 See the L<PREVENTING SHELL ESCAPES> section below for more details
363 on how C<NOEXEC> works and whether or not it will work on your system.
365 =head3 SETENV and NOSETENV
367 These tags override the value of the I<setenv> option on a per-command
368 basis. Note that if C<SETENV> has been set for a command, any
369 environment variables set on the command line way are not subject
370 to the restrictions imposed by I<env_check>, I<env_delete>, or
371 I<env_keep>. As such, only trusted users should be allowed to set
372 variables in this manner. If the command matched is B<ALL>, the
373 C<SETENV> tag is implied for that command; this default may
374 be overridden by use of the C<UNSETENV> tag.
378 B<sudo> allows shell-style I<wildcards> (aka meta or glob characters)
379 to be used in hostnames, pathnames and command line arguments in the
380 I<sudoers> file. Wildcard matching is done via the B<POSIX>
381 L<fnmatch(3)> routine. Note that these are I<not> regular expressions.
387 Matches any set of zero or more characters.
391 Matches any single character.
395 Matches any character in the specified range.
399 Matches any character B<not> in the specified range.
403 For any character "x", evaluates to "x". This is used to
404 escape special characters such as: "*", "?", "[", and "}".
408 POSIX character classes may also be used if your system's
409 L<fnmatch(3)> function supports them. However, because the
410 C<':'> character has special meaning in I<sudoers>, it must
411 be escaped. For example:
413 /bin/ls [[\:alpha\:]]*
415 Would match any filename beginning with a letter.
417 Note that a forward slash ('/') will B<not> be matched by
418 wildcards used in the pathname. When matching the command
419 line arguments, however, a slash B<does> get matched by
420 wildcards. This is to make a path like:
424 match F</usr/bin/who> but not F</usr/bin/X11/xterm>.
426 =head2 Exceptions to wildcard rules
428 The following exceptions apply to the above rules:
434 If the empty string C<""> is the only command line argument in the
435 I<sudoers> entry it means that command is not allowed to be run
436 with B<any> arguments.
440 =head2 Including other files from within sudoers
442 It is possible to include other I<sudoers> files from within the
443 I<sudoers> file currently being parsed using the C<#include>
444 directive, similar to the one used by the C preprocessor. This is
445 useful, for example, for keeping a site-wide I<sudoers> file in
446 addition to a per-machine local one. For the sake of this example
447 the site-wide I<sudoers> will be F</etc/sudoers> and the per-machine
448 one will be F</etc/sudoers.local>. To include F</etc/sudoers.local>
449 from F</etc/sudoers> we would use the following line in F</etc/sudoers>:
451 #include /etc/sudoers.local
453 When B<sudo> reaches this line it will suspend processing of the
454 current file (F</etc/sudoers>) and switch to F</etc/sudoers.local>.
455 Upon reaching the end of F</etc/sudoers.local>, the rest of
456 F</etc/sudoers> will be processed. Files that are included may
457 themselves include other files. A hard limit of 128 nested include
458 files is enforced to prevent include file loops.
460 =head2 Other special characters and reserved words
462 The pound sign ('#') is used to indicate a comment (unless it is
463 part of a #include directive or unless it occurs in the context of
464 a user name and is followed by one or more digits, in which case
465 it is treated as a uid). Both the comment character and any text
466 after it, up to the end of the line, are ignored.
468 The reserved word B<ALL> is a built-in I<alias> that always causes
469 a match to succeed. It can be used wherever one might otherwise
470 use a C<Cmnd_Alias>, C<User_Alias>, C<Runas_Alias>, or C<Host_Alias>.
471 You should not try to define your own I<alias> called B<ALL> as the
472 built-in alias will be used in preference to your own. Please note
473 that using B<ALL> can be dangerous since in a command context, it
474 allows the user to run B<any> command on the system.
476 An exclamation point ('!') can be used as a logical I<not> operator
477 both in an I<alias> and in front of a C<Cmnd>. This allows one to
478 exclude certain values. Note, however, that using a C<!> in
479 conjunction with the built-in C<ALL> alias to allow a user to
480 run "all but a few" commands rarely works as intended (see SECURITY
483 Long lines can be continued with a backslash ('\') as the last
484 character on the line.
486 Whitespace between elements in a list as well as special syntactic
487 characters in a I<User Specification> ('=', ':', '(', ')') is optional.
489 The following characters must be escaped with a backslash ('\') when
490 used as part of a word (e.g.E<nbsp>a username or hostname):
491 '@', '!', '=', ':', ',', '(', ')', '\'.
493 =head1 SUDOERS OPTIONS
495 B<sudo>'s behavior can be modified by C<Default_Entry> lines, as
496 explained earlier. A list of all supported Defaults parameters,
497 grouped by type, are listed below.
505 If set, B<sudo> will set the C<HOME> environment variable to the home
506 directory of the target user (which is root unless the B<-u> option is used).
507 This effectively means that the B<-H> option is always implied.
508 This flag is I<off> by default.
512 If set, users must authenticate themselves via a password (or other
513 means of authentication) before they may run commands. This default
514 may be overridden via the C<PASSWD> and C<NOPASSWD> tags.
515 This flag is I<on> by default.
517 =item closefrom_override
519 If set, the user may use B<sudo>'s B<-C> option which
520 overrides the default starting point at which B<sudo> begins
521 closing open file descriptors. This flag is I<off> by default.
525 If set, B<visudo> will use the value of the EDITOR or VISUAL
526 environment variables before falling back on the default editor list.
527 Note that this may create a security hole as it allows the user to
528 run any arbitrary command as root without logging. A safer alternative
529 is to place a colon-separated list of editors in the C<editor>
530 variable. B<visudo> will then only use the EDITOR or VISUAL if
531 they match a value specified in C<editor>. This flag is I<@env_editor@> by
536 If set, B<sudo> will reset the environment to only contain the
537 LOGNAME, SHELL, USER, USERNAME and the C<SUDO_*> variables. Any
538 variables in the caller's environment that match the C<env_keep>
539 and C<env_check> lists are then added. The default contents of the
540 C<env_keep> and C<env_check> lists are displayed when B<sudo> is
541 run by root with the I<-V> option. If the I<secure_path> option
542 is set, its value will be used for the C<PATH> environment variable.
543 This flag is I<on> by default.
547 Set this flag if you want to put fully qualified hostnames in the
548 I<sudoers> file. I.e., instead of myhost you would use myhost.mydomain.edu.
549 You may still use the short form if you wish (and even mix the two).
550 Beware that turning on I<fqdn> requires B<sudo> to make DNS lookups
551 which may make B<sudo> unusable if DNS stops working (for example
552 if the machine is not plugged into the network). Also note that
553 you must use the host's official name as DNS knows it. That is,
554 you may not use a host alias (C<CNAME> entry) due to performance
555 issues and the fact that there is no way to get all aliases from
556 DNS. If your machine's hostname (as returned by the C<hostname>
557 command) is already fully qualified you shouldn't need to set
558 I<fqdn>. This flag is I<@fqdn@> by default.
562 If set, B<sudo> will ignore '.' or '' (current dir) in the C<PATH>
563 environment variable; the C<PATH> itself is not modified. This
564 flag is I<@ignore_dot@> by default.
566 =item ignore_local_sudoers
568 If set via LDAP, parsing of F<@sysconfdir@/sudoers> will be skipped.
569 This is intended for Enterprises that wish to prevent the usage of local
570 sudoers files so that only LDAP is used. This thwarts the efforts of
571 rogue operators who would attempt to add roles to F<@sysconfdir@/sudoers>.
572 When this option is present, F<@sysconfdir@/sudoers> does not even need to
573 exist. Since this option tells B<sudo> how to behave when no specific LDAP
574 entries have been matched, this sudoOption is only meaningful for the
575 C<cn=defaults> section. This flag is I<off> by default.
579 If set, B<sudo> will insult users when they enter an incorrect
580 password. This flag is I<@insults@> by default.
584 If set, the hostname will be logged in the (non-syslog) B<sudo> log file.
585 This flag is I<off> by default.
589 If set, the four-digit year will be logged in the (non-syslog) B<sudo> log file.
590 This flag is I<off> by default.
592 =item long_otp_prompt
594 When validating with a One Time Password (OPT) scheme such as
595 B<S/Key> or B<OPIE>, a two-line prompt is used to make it easier
596 to cut and paste the challenge to a local window. It's not as
597 pretty as the default but some people find it more convenient. This
598 flag is I<@long_otp_prompt@> by default.
602 Send mail to the I<mailto> user every time a users runs B<sudo>.
603 This flag is I<off> by default.
607 Send mail to the I<mailto> user if the user running B<sudo> does not
608 enter the correct password. This flag is I<off> by default.
612 If set, mail will be sent to the I<mailto> user if the invoking
613 user exists in the I<sudoers> file, but is not allowed to run
614 commands on the current host. This flag is I<@mail_no_host@> by default.
618 If set, mail will be sent to the I<mailto> user if the invoking
619 user is allowed to use B<sudo> but the command they are trying is not
620 listed in their I<sudoers> file entry or is explicitly denied.
621 This flag is I<@mail_no_perms@> by default.
625 If set, mail will be sent to the I<mailto> user if the invoking
626 user is not in the I<sudoers> file. This flag is I<@mail_no_user@>
631 If set, all commands run via B<sudo> will behave as if the C<NOEXEC>
632 tag has been set, unless overridden by a C<EXEC> tag. See the
633 description of I<NOEXEC and EXEC> below as well as the L<PREVENTING SHELL
634 ESCAPES> section at the end of this manual. This flag is I<off> by default.
638 Normally, B<sudo> will tell the user when a command could not be
639 found in their C<PATH> environment variable. Some sites may wish
640 to disable this as it could be used to gather information on the
641 location of executables that the normal user does not have access
642 to. The disadvantage is that if the executable is simply not in
643 the user's C<PATH>, B<sudo> will tell the user that they are not
644 allowed to run it, which can be confusing. This flag is I<@path_info@>
647 =item passprompt_override
649 The password prompt specified by I<passprompt> will normally only
650 be used if the passwod prompt provided by systems such as PAM matches
651 the string "Password:". If I<passprompt_override> is set, I<passprompt>
652 will always be used. This flag is I<off> by default.
654 =item preserve_groups
656 By default B<sudo> will initialize the group vector to the list of
657 groups the target user is in. When I<preserve_groups> is set, the
658 user's existing group vector is left unaltered. The real and
659 effective group IDs, however, are still set to match the target
660 user. This flag is I<off> by default.
664 If set, B<sudo> will only run when the user is logged in to a real
665 tty. When this flag is set, B<sudo> can only be run from a login
666 session and not via other means such as L<cron(8)> or cgi-bin scripts.
667 This flag is I<off> by default.
671 If set, root is allowed to run B<sudo> too. Disabling this prevents users
672 from "chaining" B<sudo> commands to get a root shell by doing something
673 like C<"sudo sudo /bin/sh">. Note, however, that turning off I<root_sudo>
674 will also prevent root and from running B<sudoedit>.
675 Disabling I<root_sudo> provides no real additional security; it
676 exists purely for historical reasons.
677 This flag is I<@root_sudo@> by default.
681 If set, B<sudo> will prompt for the root password instead of the password
682 of the invoking user. This flag is I<off> by default.
686 If set, B<sudo> will prompt for the password of the user defined by the
687 I<runas_default> option (defaults to C<@runas_default@>) instead of the
688 password of the invoking user. This flag is I<off> by default.
692 If set and B<sudo> is invoked with the B<-s> option the C<HOME>
693 environment variable will be set to the home directory of the target
694 user (which is root unless the B<-u> option is used). This effectively
695 makes the B<-s> option imply B<-H>. This flag is I<off> by default.
699 Normally, B<sudo> will set the C<LOGNAME>, C<USER> and C<USERNAME>
700 environment variables to the name of the target user (usually root
701 unless the B<-u> option is given). However, since some programs
702 (including the RCS revision control system) use C<LOGNAME> to
703 determine the real identity of the user, it may be desirable to
704 change this behavior. This can be done by negating the set_logname
705 option. Note that if the I<env_reset> option has not been disabled,
706 entries in the I<env_keep> list will override the value of
707 I<set_logname>. This flag is I<off> by default.
711 Allow the user to disable the I<env_reset> option from the command
712 line. Additionally, environment variables set via the command line
713 are not subject to the restrictions imposed by I<env_check>,
714 I<env_delete>, or I<env_keep>. As such, only trusted users should
715 be allowed to set variables in this manner. This flag is I<off>
720 If set and B<sudo> is invoked with no arguments it acts as if the
721 B<-s> option had been given. That is, it runs a shell as root (the
722 shell is determined by the C<SHELL> environment variable if it is
723 set, falling back on the shell listed in the invoking user's
724 /etc/passwd entry if not). This flag is I<off> by default.
728 Normally, when B<sudo> executes a command the real and effective
729 UIDs are set to the target user (root by default). This option
730 changes that behavior such that the real UID is left as the invoking
731 user's UID. In other words, this makes B<sudo> act as a setuid
732 wrapper. This can be useful on systems that disable some potentially
733 dangerous functionality when a program is run setuid. This option
734 is only effective on systems with either the setreuid() or setresuid()
735 function. This flag is I<off> by default.
739 If set, B<sudo> will prompt for the password of the user specified by
740 the B<-u> option (defaults to C<root>) instead of the password of the
741 invoking user. Note that this precludes the use of a uid not listed
742 in the passwd database as an argument to the B<-u> option.
743 This flag is I<off> by default.
747 If set, users must authenticate on a per-tty basis. Normally,
748 B<sudo> uses a directory in the ticket dir with the same name as
749 the user running it. With this flag enabled, B<sudo> will use a
750 file named for the tty the user is logged in on in that directory.
751 This flag is I<@tty_tickets@> by default.
755 If set, B<sudo> will apply the defaults specified for the target user's
756 login class if one exists. Only available if B<sudo> is configured with
757 the --with-logincap option. This flag is I<off> by default.
761 By default, B<sudo> will refuse to run if the user must enter a
762 password but it is not possible to disable echo on the terminal.
763 If the I<visiblepw> flag is set, B<sudo> will prompt for a password
764 even when it would be visible on the screen. This makes it possible
765 to run things like C<"rsh somehost sudo ls"> since L<rsh(1)> does
766 not allocate a tty. This flag is I<off> by default.
776 Before it executes a command, B<sudo> will close all open file
777 descriptors other than standard input, standard output and standard
778 error (ie: file descriptors 0-2). The I<closefrom> option can be used
779 to specify a different file descriptor at which to start closing.
784 The number of tries a user gets to enter his/her password before
785 B<sudo> logs the failure and exits. The default is C<@passwd_tries@>.
789 B<Integers that can be used in a boolean context>:
795 Number of characters per line for the file log. This value is used
796 to decide when to wrap lines for nicer log files. This has no
797 effect on the syslog log file, only the file log. The default is
798 C<@loglen@> (use 0 or negate the option to disable word wrap).
802 Number of minutes before the B<sudo> password prompt times out.
803 The default is C<@password_timeout@>; set this to C<0> for no password timeout.
805 =item timestamp_timeout
807 Number of minutes that can elapse before B<sudo> will ask for a
808 passwd again. The default is C<@timeout@>. Set this to C<0> to always
809 prompt for a password.
810 If set to a value less than C<0> the user's timestamp will never
811 expire. This can be used to allow users to create or delete their
812 own timestamps via C<sudo -v> and C<sudo -k> respectively.
816 Umask to use when running the command. Negate this option or set
817 it to 0777 to preserve the user's umask. The actual umask that is
818 used will be the union of the user's umask and C<@sudo_umask@>.
819 This guarantees that B<sudo> never lowers the umask when running a
820 command. Note on systems that use PAM, the default PAM configuration
821 may specify its own umask which will override the value set in
830 =item badpass_message
832 Message that is displayed if a user enters an incorrect password.
833 The default is C<@badpass_message@> unless insults are enabled.
837 A colon (':') separated list of editors allowed to be used with
838 B<visudo>. B<visudo> will choose the editor that matches the user's
839 EDITOR environment variable if possible, or the first editor in the
840 list that exists and is executable. The default is the path to vi
845 Subject of the mail sent to the I<mailto> user. The escape C<%h>
846 will expand to the hostname of the machine.
847 Default is C<@mailsub@>.
851 Path to a shared library containing dummy versions of the execv(),
852 execve() and fexecve() library functions that just return an error.
853 This is used to implement the I<noexec> functionality on systems that
854 support C<LD_PRELOAD> or its equivalent. Defaults to F<@noexec_file@>.
858 The default prompt to use when asking for a password; can be overridden
859 via the B<-p> option or the C<SUDO_PROMPT> environment variable.
860 The following percent (`C<%>') escapes are supported:
866 expanded to the local hostname including the domain name
867 (on if the machine's hostname is fully qualified or the I<fqdn>
872 expanded to the local hostname without the domain name
876 expanded to the user whose password is being asked for (respects the
877 I<rootpw>, I<targetpw> and I<runaspw> flags in I<sudoers>)
881 expanded to the login name of the user the command will
882 be run as (defaults to root)
886 expanded to the invoking user's login name
890 two consecutive C<%> characters are collapsed into a single C<%> character
894 The default value is C<@passprompt@>.
898 The default SELinux role to use when constructing a new security
899 context to run the command. The default role may be overridden on
900 a per-command basis in I<sudoers> or via command line options.
901 This option is only available whe B<sudo> is built with SELinux support.
905 The default user to run commands as if the B<-u> option is not specified
906 on the command line. This defaults to C<@runas_default@>.
907 Note that if I<runas_default> is set it B<must> occur before
908 any C<Runas_Alias> specifications.
912 Syslog priority to use when user authenticates unsuccessfully.
913 Defaults to C<@badpri@>.
917 Syslog priority to use when user authenticates successfully.
918 Defaults to C<@goodpri@>.
922 Locale to use when parsing the sudoers file. Note that changing
923 the locale may affect how sudoers is interpreted.
928 The directory in which B<sudo> stores its timestamp files.
929 The default is F<@timedir@>.
933 The owner of the timestamp directory and the timestamps stored therein.
934 The default is C<root>.
938 The default SELinux type to use when constructing a new security
939 context to run the command. The default type may be overridden on
940 a per-command basis in I<sudoers> or via command line options.
941 This option is only available whe B<sudo> is built with SELinux support.
945 B<Strings that can be used in a boolean context>:
951 The I<askpass> option specifies the fully qualified path to a helper
952 program used to read the user's password when no terminal is
953 available. This may be the case when B<sudo> is executed from a
954 graphical (as opposed to text-based) application. The program
955 specified by I<askpass> should display the argument passed to it
956 as the prompt and write the user's password to the standard output.
957 The value of I<askpass> may be overridden by the C<SUDO_ASKPASS>
958 environment variable.
962 The I<env_file> options specifies the fully qualified path to a file
963 containing variables to be set in the environment of the program
964 being run. Entries in this file should be of the form C<VARIABLE=value>.
965 Variables in this file are subject to other B<sudo> environment
966 settings such as I<env_keep> and I<env_check>.
970 Users in this group are exempt from password and PATH requirements.
971 This is not set by default.
975 This option controls when a short lecture will be printed along with
976 the password prompt. It has the following possible values:
982 Always lecture the user.
986 Never lecture the user.
990 Only lecture the user the first time they run B<sudo>.
994 If no value is specified, a value of I<once> is implied.
995 Negating the option results in a value of I<never> being used.
996 The default value is I<@lecture@>.
1000 Path to a file containing an alternate B<sudo> lecture that will
1001 be used in place of the standard lecture if the named file exists.
1002 By default, B<sudo> uses a built-in lecture.
1006 This option controls when a password will be required when a
1007 user runs B<sudo> with the B<-l> option. It has the following possible values:
1013 All the user's I<sudoers> entries for the current host must have
1014 the C<NOPASSWD> flag set to avoid entering a password.
1018 The user must always enter a password to use the B<-l> option.
1022 At least one of the user's I<sudoers> entries for the current host
1023 must have the C<NOPASSWD> flag set to avoid entering a password.
1027 The user need never enter a password to use the B<-l> option.
1031 If no value is specified, a value of I<any> is implied.
1032 Negating the option results in a value of I<never> being used.
1033 The default value is I<any>.
1037 Path to the B<sudo> log file (not the syslog log file). Setting a path
1038 turns on logging to a file; negating this option turns it off.
1039 By default, B<sudo> logs via syslog.
1043 Flags to use when invoking mailer. Defaults to B<-t>.
1047 Path to mail program used to send warning mail.
1048 Defaults to the path to sendmail found at configure time.
1052 Address to use for the "from" address when sending warning and error
1053 mail. The address should be enclosed in double quotes (C<">) to
1054 protect against B<sudo> interpreting the C<@> sign. Defaults to
1055 the name of the user running B<sudo>.
1059 Address to send warning and error mail to. The address should
1060 be enclosed in double quotes (C<">) to protect against B<sudo>
1061 interpreting the C<@> sign. Defaults to C<@mailto@>.
1065 Path used for every command run from B<sudo>. If you don't trust the
1066 people running B<sudo> to have a sane C<PATH> environment variable you may
1067 want to use this. Another use is if you want to have the "root path"
1068 be separate from the "user path." Users in the group specified by the
1069 I<exempt_group> option are not affected by I<secure_path>.
1070 This is not set by default.
1074 Syslog facility if syslog is being used for logging (negate to
1075 disable syslog logging). Defaults to C<@logfac@>.
1079 This option controls when a password will be required when a user runs
1080 B<sudo> with the B<-v> option. It has the following possible values:
1086 All the user's I<sudoers> entries for the current host must have
1087 the C<NOPASSWD> flag set to avoid entering a password.
1091 The user must always enter a password to use the B<-v> option.
1095 At least one of the user's I<sudoers> entries for the current host
1096 must have the C<NOPASSWD> flag set to avoid entering a password.
1100 The user need never enter a password to use the B<-v> option.
1104 If no value is specified, a value of I<all> is implied.
1105 Negating the option results in a value of I<never> being used.
1106 The default value is I<all>.
1110 B<Lists that can be used in a boolean context>:
1116 Environment variables to be removed from the user's environment if
1117 the variable's value contains C<%> or C</> characters. This can
1118 be used to guard against printf-style format vulnerabilities in
1119 poorly-written programs. The argument may be a double-quoted,
1120 space-separated list or a single value without double-quotes. The
1121 list can be replaced, added to, deleted from, or disabled by using
1122 the C<=>, C<+=>, C<-=>, and C<!> operators respectively. Regardless
1123 of whether the C<env_reset> option is enabled or disabled, variables
1124 specified by C<env_check> will be preserved in the environment if
1125 they pass the aforementioned check. The default list of environment
1126 variables to check is displayed when B<sudo> is run by root with
1132 Not effective due to security issues: only variables listed in
1133 I<env_keep> or I<env_check> can be passed through B<sudo>!
1135 The argument may be a double-quoted, space-separated list or a
1136 single value without double-quotes. The list can be replaced, added
1137 to, deleted from, or disabled by using the C<=>, C<+=>, C<-=>, and
1138 C<!> operators respectively. The default list of environment
1139 variables to remove is displayed when B<sudo> is run by root with the
1140 I<-V> option. Note that many operating systems will remove potentially
1141 dangerous variables from the environment of any setuid process (such
1146 Environment variables to be preserved in the user's environment.
1147 This allows fine-grained
1148 control over the environment B<sudo>-spawned processes will receive.
1149 The argument may be a double-quoted, space-separated list or a
1150 single value without double-quotes. The list can be replaced, added
1151 to, deleted from, or disabled by using the C<=>, C<+=>, C<-=>, and
1152 C<!> operators respectively. The default list of variables to keep
1153 is displayed when B<sudo> is run by root with the I<-V> option.
1157 When logging via L<syslog(3)>, B<sudo> accepts the following values
1158 for the syslog facility (the value of the B<syslog> Parameter):
1159 B<authpriv> (if your OS supports it), B<auth>, B<daemon>, B<user>,
1160 B<local0>, B<local1>, B<local2>, B<local3>, B<local4>, B<local5>,
1161 B<local6>, and B<local7>. The following syslog priorities are
1162 supported: B<alert>, B<crit>, B<debug>, B<emerg>, B<err>, B<info>,
1163 B<notice>, and B<warning>.
1169 =item F<@sysconfdir@/sudoers>
1171 List of who can run what
1177 =item F</etc/netgroup>
1179 List of network groups
1185 Below are example I<sudoers> entries. Admittedly, some of
1186 these are a bit contrived. First, we define our I<aliases>:
1188 Below are example I<sudoers> entries. Admittedly, some of
1189 these are a bit contrived. First, we allow a few environment
1190 variables to pass and then define our I<aliases>:
1192 # Run X applications through sudo; HOME is used to find .Xauthority file
1193 # Note that some programs may use HOME for other purposes too and
1194 # this may lead to privilege escalation!
1195 Defaults env_keep = "DISPLAY HOME"
1197 # User alias specification
1198 User_Alias FULLTIMERS = millert, mikef, dowdy
1199 User_Alias PARTTIMERS = bostley, jwfox, crawl
1200 User_Alias WEBMASTERS = will, wendy, wim
1202 # Runas alias specification
1203 Runas_Alias OP = root, operator
1204 Runas_Alias DB = oracle, sybase
1206 # Host alias specification
1207 Host_Alias SPARC = bigtime, eclipse, moet, anchor :\
1208 SGI = grolsch, dandelion, black :\
1209 ALPHA = widget, thalamus, foobar :\
1210 HPPA = boa, nag, python
1211 Host_Alias CUNETS = 128.138.0.0/255.255.0.0
1212 Host_Alias CSNETS = 128.138.243.0, 128.138.204.0/24, 128.138.242.0
1213 Host_Alias SERVERS = master, mail, www, ns
1214 Host_Alias CDROM = orion, perseus, hercules
1216 # Cmnd alias specification
1217 Cmnd_Alias DUMPS = /usr/bin/mt, /usr/sbin/dump, /usr/sbin/rdump,\
1218 /usr/sbin/restore, /usr/sbin/rrestore
1219 Cmnd_Alias KILL = /usr/bin/kill
1220 Cmnd_Alias PRINTING = /usr/sbin/lpc, /usr/bin/lprm
1221 Cmnd_Alias SHUTDOWN = /usr/sbin/shutdown
1222 Cmnd_Alias HALT = /usr/sbin/halt
1223 Cmnd_Alias REBOOT = /usr/sbin/reboot
1224 Cmnd_Alias SHELLS = /usr/bin/sh, /usr/bin/csh, /usr/bin/ksh, \
1225 /usr/local/bin/tcsh, /usr/bin/rsh, \
1227 Cmnd_Alias SU = /usr/bin/su
1228 Cmnd_Alias PAGERS = /usr/bin/more, /usr/bin/pg, /usr/bin/less
1230 Here we override some of the compiled in default values. We want
1231 B<sudo> to log via L<syslog(3)> using the I<auth> facility in all
1232 cases. We don't want to subject the full time staff to the B<sudo>
1233 lecture, user B<millert> need not give a password, and we don't
1234 want to reset the C<LOGNAME>, C<USER> or C<USERNAME> environment
1235 variables when running commands as root. Additionally, on the
1236 machines in the I<SERVERS> C<Host_Alias>, we keep an additional
1237 local log file and make sure we log the year in each log line since
1238 the log entries will be kept around for several years. Lastly, we
1239 disable shell escapes for the commands in the PAGERS C<Cmnd_Alias>
1240 (F</usr/bin/more>, F</usr/bin/pg> and F</usr/bin/less>).
1242 # Override built-in defaults
1243 Defaults syslog=auth
1244 Defaults>root !set_logname
1245 Defaults:FULLTIMERS !lecture
1246 Defaults:millert !authenticate
1247 Defaults@SERVERS log_year, logfile=/var/log/sudo.log
1248 Defaults!PAGERS noexec
1250 The I<User specification> is the part that actually determines who may
1253 root ALL = (ALL) ALL
1254 %wheel ALL = (ALL) ALL
1256 We let B<root> and any user in group B<wheel> run any command on any
1259 FULLTIMERS ALL = NOPASSWD: ALL
1261 Full time sysadmins (B<millert>, B<mikef>, and B<dowdy>) may run any
1262 command on any host without authenticating themselves.
1264 PARTTIMERS ALL = ALL
1266 Part time sysadmins (B<bostley>, B<jwfox>, and B<crawl>) may run any
1267 command on any host but they must authenticate themselves first
1268 (since the entry lacks the C<NOPASSWD> tag).
1272 The user B<jack> may run any command on the machines in the I<CSNETS> alias
1273 (the networks C<128.138.243.0>, C<128.138.204.0>, and C<128.138.242.0>).
1274 Of those networks, only C<128.138.204.0> has an explicit netmask (in
1275 CIDR notation) indicating it is a class C network. For the other
1276 networks in I<CSNETS>, the local machine's netmask will be used
1281 The user B<lisa> may run any command on any host in the I<CUNETS> alias
1282 (the class B network C<128.138.0.0>).
1284 operator ALL = DUMPS, KILL, SHUTDOWN, HALT, REBOOT, PRINTING,\
1285 sudoedit /etc/printcap, /usr/oper/bin/
1287 The B<operator> user may run commands limited to simple maintenance.
1288 Here, those are commands related to backups, killing processes, the
1289 printing system, shutting down the system, and any commands in the
1290 directory F</usr/oper/bin/>.
1292 joe ALL = /usr/bin/su operator
1294 The user B<joe> may only L<su(1)> to operator.
1296 pete HPPA = /usr/bin/passwd [A-Za-z]*, !/usr/bin/passwd root
1298 The user B<pete> is allowed to change anyone's password except for
1299 root on the I<HPPA> machines. Note that this assumes L<passwd(1)>
1300 does not take multiple usernames on the command line.
1302 bob SPARC = (OP) ALL : SGI = (OP) ALL
1304 The user B<bob> may run anything on the I<SPARC> and I<SGI> machines
1305 as any user listed in the I<OP> C<Runas_Alias> (B<root> and B<operator>).
1309 The user B<jim> may run any command on machines in the I<biglab> netgroup.
1310 B<sudo> knows that "biglab" is a netgroup due to the '+' prefix.
1312 +secretaries ALL = PRINTING, /usr/bin/adduser, /usr/bin/rmuser
1314 Users in the B<secretaries> netgroup need to help manage the printers
1315 as well as add and remove users, so they are allowed to run those
1316 commands on all machines.
1318 fred ALL = (DB) NOPASSWD: ALL
1320 The user B<fred> can run commands as any user in the I<DB> C<Runas_Alias>
1321 (B<oracle> or B<sybase>) without giving a password.
1323 john ALPHA = /usr/bin/su [!-]*, !/usr/bin/su *root*
1325 On the I<ALPHA> machines, user B<john> may su to anyone except root
1326 but he is not allowed to specify any options to the L<su(1)> command.
1328 jen ALL, !SERVERS = ALL
1330 The user B<jen> may run any command on any machine except for those
1331 in the I<SERVERS> C<Host_Alias> (master, mail, www and ns).
1333 jill SERVERS = /usr/bin/, !SU, !SHELLS
1335 For any machine in the I<SERVERS> C<Host_Alias>, B<jill> may run
1336 any commands in the directory F</usr/bin/> except for those commands
1337 belonging to the I<SU> and I<SHELLS> C<Cmnd_Aliases>.
1339 steve CSNETS = (operator) /usr/local/op_commands/
1341 The user B<steve> may run any command in the directory /usr/local/op_commands/
1342 but only as user operator.
1344 matt valkyrie = KILL
1346 On his personal workstation, valkyrie, B<matt> needs to be able to
1347 kill hung processes.
1349 WEBMASTERS www = (www) ALL, (root) /usr/bin/su www
1351 On the host www, any user in the I<WEBMASTERS> C<User_Alias> (will,
1352 wendy, and wim), may run any command as user www (which owns the
1353 web pages) or simply L<su(1)> to www.
1355 ALL CDROM = NOPASSWD: /sbin/umount /CDROM,\
1356 /sbin/mount -o nosuid\,nodev /dev/cd0a /CDROM
1358 Any user may mount or unmount a CD-ROM on the machines in the CDROM
1359 C<Host_Alias> (orion, perseus, hercules) without entering a password.
1360 This is a bit tedious for users to type, so it is a prime candidate
1361 for encapsulating in a shell script.
1363 =head1 SECURITY NOTES
1365 It is generally not effective to "subtract" commands from C<ALL>
1366 using the '!' operator. A user can trivially circumvent this
1367 by copying the desired command to a different name and then
1368 executing that. For example:
1370 bill ALL = ALL, !SU, !SHELLS
1372 Doesn't really prevent B<bill> from running the commands listed in
1373 I<SU> or I<SHELLS> since he can simply copy those commands to a
1374 different name, or use a shell escape from an editor or other
1375 program. Therefore, these kind of restrictions should be considered
1376 advisory at best (and reinforced by policy).
1378 =head1 PREVENTING SHELL ESCAPES
1380 Once B<sudo> executes a program, that program is free to do whatever
1381 it pleases, including run other programs. This can be a security
1382 issue since it is not uncommon for a program to allow shell escapes,
1383 which lets a user bypass B<sudo>'s access control and logging.
1384 Common programs that permit shell escapes include shells (obviously),
1385 editors, paginators, mail and terminal programs.
1387 There are two basic approaches to this problem:
1393 Avoid giving users access to commands that allow the user to run
1394 arbitrary commands. Many editors have a restricted mode where shell
1395 escapes are disabled, though B<sudoedit> is a better solution to
1396 running editors via B<sudo>. Due to the large number of programs that
1397 offer shell escapes, restricting users to the set of programs that
1398 do not if often unworkable.
1402 Many systems that support shared libraries have the ability to
1403 override default library functions by pointing an environment
1404 variable (usually C<LD_PRELOAD>) to an alternate shared library.
1405 On such systems, B<sudo>'s I<noexec> functionality can be used to
1406 prevent a program run by B<sudo> from executing any other programs.
1407 Note, however, that this applies only to native dynamically-linked
1408 executables. Statically-linked executables and foreign executables
1409 running under binary emulation are not affected.
1411 To tell whether or not B<sudo> supports I<noexec>, you can run
1412 the following as root:
1414 sudo -V | grep "dummy exec"
1416 If the resulting output contains a line that begins with:
1418 File containing dummy exec functions:
1420 then B<sudo> may be able to replace the exec family of functions
1421 in the standard library with its own that simply return an error.
1422 Unfortunately, there is no foolproof way to know whether or not
1423 I<noexec> will work at compile-time. I<noexec> should work on
1424 SunOS, Solaris, *BSD, Linux, IRIX, Tru64 UNIX, MacOS X, and HP-UX
1425 11.x. It is known B<not> to work on AIX and UnixWare. I<noexec>
1426 is expected to work on most operating systems that support the
1427 C<LD_PRELOAD> environment variable. Check your operating system's
1428 manual pages for the dynamic linker (usually ld.so, ld.so.1, dyld,
1429 dld.sl, rld, or loader) to see if C<LD_PRELOAD> is supported.
1431 To enable I<noexec> for a command, use the C<NOEXEC> tag as documented
1432 in the User Specification section above. Here is that example again:
1434 aaron shanty = NOEXEC: /usr/bin/more, /usr/bin/vi
1436 This allows user B<aaron> to run F</usr/bin/more> and F</usr/bin/vi>
1437 with I<noexec> enabled. This will prevent those two commands from
1438 executing other commands (such as a shell). If you are unsure
1439 whether or not your system is capable of supporting I<noexec> you
1440 can always just try it out and see if it works.
1444 Note that restricting shell escapes is not a panacea. Programs
1445 running as root are still capable of many potentially hazardous
1446 operations (such as changing or overwriting files) that could lead
1447 to unintended privilege escalation. In the specific case of an
1448 editor, a safer approach is to give the user permission to run
1453 L<rsh(1)>, L<su(1)>, L<fnmatch(3)>, L<sudo(8)>, L<visudo(8)>
1457 The I<sudoers> file should B<always> be edited by the B<visudo>
1458 command which locks the file and does grammatical checking. It is
1459 imperative that I<sudoers> be free of syntax errors since B<sudo>
1460 will not run with a syntactically incorrect I<sudoers> file.
1462 When using netgroups of machines (as opposed to users), if you
1463 store fully qualified hostnames in the netgroup (as is usually the
1464 case), you either need to have the machine's hostname be fully qualified
1465 as returned by the C<hostname> command or use the I<fqdn> option in
1470 If you feel you have found a bug in B<sudo>, please submit a bug report
1471 at http://www.sudo.ws/sudo/bugs/
1475 Limited free support is available via the sudo-users mailing list,
1476 see http://www.sudo.ws/mailman/listinfo/sudo-users to subscribe or
1477 search the archives.
1481 B<sudo> is provided ``AS IS'' and any express or implied warranties,
1482 including, but not limited to, the implied warranties of merchantability
1483 and fitness for a particular purpose are disclaimed. See the LICENSE
1484 file distributed with B<sudo> or http://www.sudo.ws/sudo/license.html
1485 for complete details.