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1 .TH SLAPD.ACCESS 5 "2008/07/16" "OpenLDAP 2.4.11"
2 .\" Copyright 1998-2008 The OpenLDAP Foundation All Rights Reserved.
3 .\" Copying restrictions apply. See COPYRIGHT/LICENSE.
4 .\" $OpenLDAP: pkg/ldap/doc/man/man5/slapd.access.5,v 1.70.2.10 2008/07/09 00:48:35 quanah Exp $
5 .SH NAME
6 slapd.access \- access configuration for slapd, the stand-alone LDAP daemon
7 .SH SYNOPSIS
8 /etc/openldap/slapd.conf
9 .SH DESCRIPTION
10 The
11 .BR slapd.conf (5)
12 file contains configuration information for the
13 .BR slapd (8)
14 daemon. This configuration file is also used by the SLAPD tools
15 .BR slapacl (8),
16 .BR slapadd (8),
17 .BR slapauth (8),
18 .BR slapcat (8),
19 .BR slapdn (8),
20 .BR slapindex (8),
21 and
22 .BR slaptest (8).
23 .LP
24 The
25 .B slapd.conf
26 file consists of a series of global configuration options that apply to
27 .B slapd
28 as a whole (including all backends), followed by zero or more database
29 backend definitions that contain information specific to a backend
30 instance.
31 .LP
32 The general format of
33 .B slapd.conf
34 is as follows:
35 .LP
36 .nf
37 # comment - these options apply to every database
38 <global configuration options>
39 # first database definition & configuration options
40 database <backend 1 type>
41 <configuration options specific to backend 1>
42 # subsequent database definitions & configuration options
43 ...
44 .fi
45 .LP
46 Both the global configuration and each backend-specific section can
47 contain access information. Backend-specific access control
48 directives are used for those entries that belong to the backend,
49 according to their naming context. In case no access control
50 directives are defined for a backend or those which are defined are
51 not applicable, the directives from the global configuration section
52 are then used.
53 .LP
54 If no access controls are present, the default policy
55 allows anyone and everyone to read anything but restricts
56 updates to rootdn. (e.g., "access to * by * read").
57 The rootdn can always read and write EVERYTHING!
58 .LP
59 For entries not held in any backend (such as a root DSE), the
60 directives of the first backend (and any global directives) are
61 used.
62 .LP
63 Arguments that should be replaced by actual text are shown in
64 brackets <>.
65 .SH THE ACCESS DIRECTIVE
66 The structure of the access control directives is
67 .TP
68 .B access to <what> "[ by <who> [ <access> ] [ <control> ] ]+"
69 Grant access (specified by
70 .BR <access> )
71 to a set of entries and/or attributes (specified by
72 .BR <what> )
73 by one or more requestors (specified by
74 .BR <who> ).
76 .LP
77 Lists of access directives are evaluated in the order they appear
78 in \fIslapd.conf\fP.
79 When a
80 .B <what>
81 clause matches the datum whose access is being evaluated, its
82 .B <who>
83 clause list is checked.
84 When a
85 .B <who>
86 clause matches the accessor's properties, its
87 .B <access>
88 and
89 .B <control>
90 clauses are evaluated.
91 Access control checking stops at the first match of the
92 .B <what>
93 and
94 .B <who>
95 clause, unless otherwise dictated by the
96 .B <control>
97 clause.
98 Each
99 .B <who>
100 clause list is implicitly terminated by a
101 .LP
102 .nf
103 by * none stop
104 .fi
105 .LP
106 clause that results in stopping the access control with no access
107 privileges granted.
108 Each
109 .B <what>
110 clause list is implicitly terminated by a
111 .LP
112 .nf
113 access to *
114 by * none
115 .fi
116 .LP
117 clause that results in granting no access privileges to an otherwise
118 unspecified datum.
119 .SH THE <WHAT> FIELD
120 The field
121 .BR <what>
122 specifies the entity the access control directive applies to.
123 It can have the forms
124 .LP
125 .nf
126 dn[.<dnstyle>]=<dnpattern>
127 filter=<ldapfilter>
128 attrs=<attrlist>[ val[/matchingRule][.<attrstyle>]=<attrval>]
129 .fi
130 .LP
131 with
132 .LP
133 .nf
134 <dnstyle>={{exact|base(object)}|regex
135 |one(level)|sub(tree)|children}
136 <attrlist>={<attr>|[{!|@}]<objectClass>}[,<attrlist>]
137 <attrstyle>={{exact|base(object)}|regex
138 |one(level)|sub(tree)|children}
139 .fi
140 .LP
141 The statement
142 .B dn=<dnpattern>
143 selects the entries based on their naming context.
144 The
145 .B <dnpattern>
146 is a string representation of the entry's DN.
147 The wildcard
148 .B *
149 stands for all the entries, and it is implied if no
150 .B dn
151 form is given.
152 .LP
153 The
154 .B <dnstyle>
155 is optional; however, it is recommended to specify it to avoid ambiguities.
156 .B Base
157 (synonym of
158 .BR baseObject ),
159 the default,
160 or
161 .B exact
162 (an alias of
163 .BR base )
164 indicates the entry whose DN is equal to the
165 .BR <dnpattern> ;
166 .B one
167 (synonym of
168 .BR onelevel )
169 indicates all the entries immediately below the
170 .BR <dnpattern> ,
171 .B sub
172 (synonym of
173 .BR subtree )
174 indicates all entries in the subtree at the
175 .BR <dnpattern> ,
176 .B children
177 indicates all the entries below (subordinate to) the
178 .BR <dnpattern> .
179 .LP
180 If the
181 .B <dnstyle>
182 qualifier is
183 .BR regex ,
184 then
185 .B <dnpattern>
186 is a POSIX (''extended'') regular expression pattern,
187 as detailed in
188 .BR regex (7)
189 and/or
190 .BR re_format (7),
191 matching a normalized string representation of the entry's DN.
192 The regex form of the pattern does not (yet) support UTF\-8.
193 .LP
194 The statement
195 .B filter=<ldapfilter>
196 selects the entries based on a valid LDAP filter as described in RFC 4515.
197 A filter of
198 .B (objectClass=*)
199 is implied if no
200 .B filter
201 form is given.
202 .LP
203 The statement
204 .B attrs=<attrlist>
205 selects the attributes the access control rule applies to.
206 It is a comma-separated list of attribute types, plus the special names
207 .BR entry ,
208 indicating access to the entry itself, and
209 .BR children ,
210 indicating access to the entry's children. ObjectClass names may also
211 be specified in this list, which will affect all the attributes that
212 are required and/or allowed by that objectClass.
213 Actually, names in
214 .B <attrlist>
215 that are prefixed by
216 .B @
217 are directly treated as objectClass names. A name prefixed by
218 .B !
219 is also treated as an objectClass, but in this case the access rule
220 affects the attributes that are not required nor allowed
221 by that objectClass.
222 If no
223 .B attrs
224 form is given,
225 .B attrs=@extensibleObject
226 is implied, i.e. all attributes are addressed.
227 .LP
228 Using the form
229 .B attrs=<attr> val[/matchingRule][.<attrstyle>]=<attrval>
230 specifies access to a particular value of a single attribute.
231 In this case, only a single attribute type may be given. The
232 .B <attrstyle>
233 .B exact
234 (the default) uses the attribute's equality matching rule to compare the
235 value, unless a different (and compatible) matching rule is specified. If the
236 .B <attrstyle>
237 is
238 .BR regex ,
239 the provided value is used as a POSIX (''extended'') regular
240 expression pattern. If the attribute has DN syntax, the
241 .B <attrstyle>
242 can be any of
243 .BR base ,
244 .BR onelevel ,
245 .B subtree
246 or
247 .BR children ,
248 resulting in base, onelevel, subtree or children match, respectively.
249 .LP
250 The dn, filter, and attrs statements are additive; they can be used in sequence
251 to select entities the access rule applies to based on naming context,
252 value and attribute type simultaneously.
253 .SH THE <WHO> FIELD
254 The field
255 .B <who>
256 indicates whom the access rules apply to.
257 Multiple
258 .B <who>
259 statements can appear in an access control statement, indicating the
260 different access privileges to the same resource that apply to different
261 accessee.
262 It can have the forms
263 .LP
264 .nf
265 *
266 anonymous
267 users
268 self[.<selfstyle>]
270 dn[.<dnstyle>[,<modifier>]]=<DN>
271 dnattr=<attrname>
273 realanonymous
274 realusers
275 realself[.<selfstyle>]
277 realdn[.<dnstyle>[,<modifier>]]=<DN>
278 realdnattr=<attrname>
280 group[/<objectclass>[/<attrname>]]
281 [.<groupstyle>]=<group>
282 peername[.<peernamestyle>]=<peername>
283 sockname[.<style>]=<sockname>
284 domain[.<domainstyle>[,<modifier>]]=<domain>
285 sockurl[.<style>]=<sockurl>
286 set[.<setstyle>]=<pattern>
288 ssf=<n>
289 transport_ssf=<n>
290 tls_ssf=<n>
291 sasl_ssf=<n>
293 dynacl/<name>[/<options>][.<dynstyle>][=<pattern>]
294 .fi
295 .LP
296 with
297 .LP
298 .nf
299 <style>={exact|regex|expand}
300 <selfstyle>={level{<n>}}
301 <dnstyle>={{exact|base(object)}|regex
302 |one(level)|sub(tree)|children|level{<n>}}
303 <groupstyle>={exact|expand}
304 <peernamestyle>={<style>|ip|ipv6|path}
305 <domainstyle>={exact|regex|sub(tree)}
306 <setstyle>={exact|regex}
307 <modifier>={expand}
308 <name>=aci <pattern>=<attrname>]
309 .fi
310 .LP
311 They may be specified in combination.
312 .LP
313 .nf
314 .fi
315 .LP
316 The wildcard
317 .B *
318 refers to everybody.
319 .LP
320 The keywords prefixed by
321 .B real
322 act as their counterparts without prefix; the checking respectively occurs
323 with the \fIauthentication\fP DN and the \fIauthorization\fP DN.
324 .LP
325 The keyword
326 .B anonymous
327 means access is granted to unauthenticated clients; it is mostly used
328 to limit access to authentication resources (e.g. the
329 .B userPassword
330 attribute) to unauthenticated clients for authentication purposes.
331 .LP
332 The keyword
333 .B users
334 means access is granted to authenticated clients.
335 .LP
336 The keyword
337 .B self
338 means access to an entry is allowed to the entry itself (e.g. the entry
339 being accessed and the requesting entry must be the same).
340 It allows the
341 .B level{<n>}
342 style, where \fI<n>\fP indicates what ancestor of the DN
343 is to be used in matches.
344 A positive value indicates that the <n>-th ancestor of the user's DN
345 is to be considered; a negative value indicates that the <n>-th ancestor
346 of the target is to be considered.
347 For example, a "\fIby self.level{1} ...\fP" clause would match
348 when the object "\fIdc=example,dc=com\fP" is accessed
349 by "\fIcn=User,dc=example,dc=com\fP".
350 A "\fIby self.level{-1} ...\fP" clause would match when the same user
351 accesses the object "\fIou=Address Book,cn=User,dc=example,dc=com\fP".
352 .LP
353 The statement
354 .B dn=<DN>
355 means that access is granted to the matching DN.
356 The optional style qualifier
357 .B dnstyle
358 allows the same choices of the dn form of the
359 .B <what>
360 field. In addition, the
361 .B regex
362 style can exploit substring substitution of submatches in the
363 .B <what>
364 dn.regex clause by using the form
365 .BR $<digit> ,
366 with
367 .B digit
368 ranging from 0 to 9 (where 0 matches the entire string),
369 or the form
370 .BR ${<digit>+} ,
371 for submatches higher than 9.
372 Since the dollar character is used to indicate a substring replacement,
373 the dollar character that is used to indicate match up to the end of
374 the string must be escaped by a second dollar character, e.g.
375 .LP
376 .nf
377 access to dn.regex="^(.+,)?uid=([^,]+),dc=[^,]+,dc=com$"
378 by dn.regex="^uid=$2,dc=[^,]+,dc=com$$" write
379 .fi
380 .LP
381 The style qualifier
382 allows an optional
383 .BR modifier .
384 At present, the only type allowed is
385 .BR expand ,
386 which causes substring substitution of submatches to take place
387 even if
388 .B dnstyle
389 is not
390 .BR regex .
391 Note that the
392 .B regex
393 dnstyle in the above example may be of use only if the
394 .B <by>
395 clause needs to be a regex; otherwise, if the
396 value of the second (from the right)
397 .B dc=
398 portion of the DN in the above example were fixed, the form
399 .LP
400 .nf
401 access to dn.regex="^(.+,)?uid=([^,]+),dc=example,dc=com$"
402 by dn.exact,expand="uid=$2,dc=example,dc=com" write
403 .fi
404 .LP
405 could be used; if it had to match the value in the
406 .B <what>
407 clause, the form
408 .LP
409 .nf
410 access to dn.regex="^(.+,)?uid=([^,]+),dc=([^,]+),dc=com$"
411 by dn.exact,expand="uid=$2,dc=$3,dc=com" write
412 .fi
413 .LP
414 could be used.
415 .LP
416 Forms of the
417 .B <what>
418 clause other than regex may provide submatches as well.
419 The
420 .BR base(object) ,
421 the
422 .BR sub(tree) ,
423 the
424 .BR one(level) ,
425 and the
426 .BR children
427 forms provide
428 .B $0
429 as the match of the entire string.
430 The
431 .BR sub(tree) ,
432 the
433 .BR one(level) ,
434 and the
435 .BR children
436 forms also provide
437 .B $1
438 as the match of the rightmost part of the DN as defined in the
439 .B <what>
440 clause.
441 This may be useful, for instance, to provide access to all the
442 ancestors of a user by defining
443 .LP
444 .nf
445 access to dn.subtree="dc=com"
446 by dn.subtree,expand="$1" read
447 .fi
448 .LP
449 which means that only access to entries that appear in the DN of the
450 .B <by>
451 clause is allowed.
452 .LP
453 The
454 .BR level{<n>}
455 form is an extension and a generalization of the
456 .BR onelevel
457 form, which matches all DNs whose <n>-th ancestor is the pattern.
458 So, \fIlevel{1}\fP is equivalent to \fIonelevel\fP,
459 and \fIlevel{0}\fP is equivalent to \fIbase\fP.
460 .LP
461 It is perfectly useless to give any access privileges to a DN
462 that exactly matches the
463 .B rootdn
464 of the database the ACLs apply to, because it implicitly
465 possesses write privileges for the entire tree of that database.
466 Actually, access control is bypassed for the
467 .BR rootdn ,
468 to solve the intrinsic chicken-and-egg problem.
469 .LP
470 The statement
471 .B dnattr=<attrname>
472 means that access is granted to requests whose DN is listed in the
473 entry being accessed under the
474 .B <attrname>
475 attribute.
476 .LP
477 The statement
478 .B group=<group>
479 means that access is granted to requests whose DN is listed
480 in the group entry whose DN is given by
481 .BR <group> .
482 The optional parameters
483 .B <objectclass>
484 and
485 .B <attrname>
486 define the objectClass and the member attributeType of the group entry.
487 The defaults are
488 .B groupOfNames
489 and
490 .BR member ,
491 respectively.
492 The optional style qualifier
493 .B <style>
494 can be
495 .BR expand ,
496 which means that
497 .B <group>
498 will be expanded as a replacement string (but not as a regular expression)
499 according to
500 .BR regex (7)
501 and/or
502 .BR re_format (7),
503 and
504 .BR exact ,
505 which means that exact match will be used.
506 If the style of the DN portion of the
507 .B <what>
508 clause is regex, the submatches are made available according to
509 .BR regex (7)
510 and/or
511 .BR re_format (7);
512 other styles provide limited submatches as discussed above about
513 the DN form of the
514 .B <by>
515 clause.
516 .LP
517 For static groups, the specified attributeType must have
518 .B DistinguishedName
519 or
520 .B NameAndOptionalUID
521 syntax. For dynamic groups the attributeType must
522 be a subtype of the
523 .B labeledURI
524 attributeType. Only LDAP URIs of the form
525 .B ldap:///<base>??<scope>?<filter>
526 will be evaluated in a dynamic group, by searching the local server only.
527 .LP
528 The statements
529 .BR peername=<peername> ,
530 .BR sockname=<sockname> ,
531 .BR domain=<domain> ,
532 and
533 .BR sockurl=<sockurl>
534 mean that the contacting host IP (in the form
535 .BR "IP=<ip>:<port>"
536 for IPv4, or
537 .BR "IP=[<ipv6>]:<port>"
538 for IPv6)
539 or the contacting host named pipe file name (in the form
540 .B "PATH=<path>"
541 if connecting through a named pipe) for
542 .BR peername ,
543 the named pipe file name for
544 .BR sockname ,
545 the contacting host name for
546 .BR domain ,
547 and the contacting URL for
548 .BR sockurl
549 are compared against
550 .B pattern
551 to determine access.
552 The same
553 .B style
554 rules for pattern match described for the
555 .B group
556 case apply, plus the
557 .B regex
558 style, which implies submatch
559 .B expand
560 and regex match of the corresponding connection parameters.
561 The
562 .B exact
563 style of the
564 .BR <peername>
565 clause (the default) implies a case-exact match on the client's
566 .BR IP ,
567 including the
568 .B "IP="
569 prefix and the trailing
570 .BR ":<port>" ,
571 or the client's
572 .BR path ,
573 including the
574 .B "PATH="
575 prefix if connecting through a named pipe.
576 The special
577 .B ip
578 style interprets the pattern as
579 .BR <peername>=<ip>[%<mask>][{<n>}] ,
580 where
581 .B <ip>
582 and
583 .B <mask>
584 are dotted digit representations of the IP and the mask, while
585 .BR <n> ,
586 delimited by curly brackets, is an optional port.
587 The same applies to IPv6 addresses when the special
588 .B ipv6
589 style is used.
590 When checking access privileges, the IP portion of the
591 .BR peername
592 is extracted, eliminating the
593 .B "IP="
594 prefix and the
595 .B ":<port>"
596 part, and it is compared against the
597 .B <ip>
598 portion of the pattern after masking with
599 .BR <mask> :
600 \fI((peername & <mask>) == <ip>)\fP.
601 As an example,
602 .B peername.ip=127.0.0.1
603 and
604 .B peername.ipv6=::1
605 allow connections only from localhost,
606 .B peername.ip=192.168.1.0%255.255.255.0
607 allows connections from any IP in the 192.168.1 class C domain, and
608 .B peername.ip=192.168.1.16%255.255.255.240{9009}
609 allows connections from any IP in the 192.168.1.[16-31] range
610 of the same domain, only if port 9009 is used.
611 The special
612 .B path
613 style eliminates the
614 .B "PATH="
615 prefix from the
616 .B peername
617 when connecting through a named pipe, and performs an exact match
618 on the given pattern.
619 The
620 .BR <domain>
621 clause also allows the
622 .B subtree
623 style, which succeeds when a fully qualified name exactly matches the
624 .BR domain
625 pattern, or its trailing part, after a
626 .BR dot ,
627 exactly matches the
628 .BR domain
629 pattern.
630 The
631 .B expand
632 style is allowed, implying an
633 .B exact
634 match with submatch expansion; the use of
635 .B expand
636 as a style modifier is considered more appropriate.
637 As an example,
638 .B domain.subtree=example.com
639 will match www.example.com, but will not match www.anotherexample.com.
640 The
641 .B domain
642 of the contacting host is determined by performing a DNS reverse lookup.
643 As this lookup can easily be spoofed, use of the
644 .B domain
645 statement is strongly discouraged. By default, reverse lookups are disabled.
646 The optional
647 .B domainstyle
648 qualifier of the
649 .B <domain>
650 clause allows a
651 .B modifier
652 option; the only value currently supported is
653 .BR expand ,
654 which causes substring substitution of submatches to take place even if
655 the
656 .B domainstyle
657 is not
658 .BR regex ,
659 much like the analogous usage in
660 .B <dn>
661 clause.
662 .LP
663 The statement
664 .B set=<pattern>
665 is undocumented yet.
666 .LP
667 The statement
668 .B dynacl/<name>[/<options>][.<dynstyle>][=<pattern>]
669 means that access checking is delegated to the admin-defined method
670 indicated by
671 .BR <name> ,
672 which can be registered at run-time by means of the
673 .B moduleload
674 statement.
675 The fields
676 .BR <options> ,
677 .B <dynstyle>
678 and
679 .B <pattern>
680 are optional, and are directly passed to the registered parsing routine.
681 Dynacl is experimental; it must be enabled at compile time.
682 .LP
683 The statement
684 .B dynacl/aci[=<attrname>]
685 means that the access control is determined by the values in the
686 .B attrname
687 of the entry itself.
688 The optional
689 .B <attrname>
690 indicates what attributeType holds the ACI information in the entry.
691 By default, the
692 .B OpenLDAPaci
693 operational attribute is used.
694 ACIs are experimental; they must be enabled at compile time.
695 .LP
696 The statements
697 .BR ssf=<n> ,
698 .BR transport_ssf=<n> ,
699 .BR tls_ssf=<n> ,
700 and
701 .BR sasl_ssf=<n>
702 set the minimum required Security Strength Factor (ssf) needed
703 to grant access. The value should be positive integer.
704 .SH THE <ACCESS> FIELD
705 The optional field
706 .B <access> ::= [[real]self]{<level>|<priv>}
707 determines the access level or the specific access privileges the
708 .B who
709 field will have.
710 Its component are defined as
711 .LP
712 .nf
713 <level> ::= none|disclose|auth|compare|search|read|{write|add|delete}|manage
714 <priv> ::= {=|+|-}{0|d|x|c|s|r|{w|a|z}|m}+
715 .fi
716 .LP
717 The modifier
718 .B self
719 allows special operations like having a certain access level or privilege
720 only in case the operation involves the name of the user that's requesting
721 the access.
722 It implies the user that requests access is authorized.
723 The modifier
724 .B realself
725 refers to the authenticated DN as opposed to the authorized DN of the
726 .B self
727 modifier.
728 An example is the
729 .B selfwrite
730 access to the member attribute of a group, which allows one to add/delete
731 its own DN from the member list of a group, without affecting other members.
732 .LP
733 The
734 .B level
735 access model relies on an incremental interpretation of the access
736 privileges.
737 The possible levels are
738 .BR none ,
739 .BR disclose ,
740 .BR auth ,
741 .BR compare ,
742 .BR search ,
743 .BR read ,
744 .BR write ,
745 and
746 .BR manage .
747 Each access level implies all the preceding ones, thus
748 .B manage
749 grants all access including administrative access.
750 The
751 .BR write
752 access is actually the combination of
753 .BR add
754 and
755 .BR delete ,
756 which respectively restrict the write privilege to add or delete
757 the specified
758 .BR <what> .
760 .LP
761 The
762 .B none
763 access level disallows all access including disclosure on error.
764 .LP
765 The
766 .B disclose
767 access level allows disclosure of information on error.
768 .LP
769 The
770 .B auth
771 access level means that one is allowed access to an attribute to perform
772 authentication/authorization operations (e.g.
773 .BR bind )
774 with no other access.
775 This is useful to grant unauthenticated clients the least possible
776 access level to critical resources, like passwords.
777 .LP
778 The
779 .B priv
780 access model relies on the explicit setting of access privileges
781 for each clause.
782 The
783 .B =
784 sign resets previously defined accesses; as a consequence, the final
785 access privileges will be only those defined by the clause.
786 The
787 .B +
788 and
789 .B -
790 signs add/remove access privileges to the existing ones.
791 The privileges are
792 .B m
793 for manage,
794 .B w
795 for write,
796 .B a
797 for add,
798 .B z
799 for delete,
800 .B r
801 for read,
802 .B s
803 for search,
804 .B c
805 for compare,
806 .B x
807 for authentication, and
808 .B d
809 for disclose.
810 More than one of the above privileges can be added in one statement.
811 .B 0
812 indicates no privileges and is used only by itself (e.g., +0).
813 Note that
814 .B +az
815 is equivalent to
816 .BR +w .
817 .LP
818 If no access is given, it defaults to
819 .BR +0 .
820 .SH THE <CONTROL> FIELD
821 The optional field
822 .B <control>
823 controls the flow of access rule application.
824 It can have the forms
825 .LP
826 .nf
827 stop
828 continue
829 break
830 .fi
831 .LP
832 where
833 .BR stop ,
834 the default, means access checking stops in case of match.
835 The other two forms are used to keep on processing access clauses.
836 In detail, the
837 .B continue
838 form allows for other
839 .B <who>
840 clauses in the same
841 .B <access>
842 clause to be considered, so that they may result in incrementally altering
843 the privileges, while the
844 .B break
845 form allows for other
846 .B <access>
847 clauses that match the same target to be processed.
848 Consider the (silly) example
849 .LP
850 .nf
851 access to dn.subtree="dc=example,dc=com" attrs=cn
852 by * =cs break
854 access to dn.subtree="ou=People,dc=example,dc=com"
855 by * +r
856 .fi
857 .LP
858 which allows search and compare privileges to everybody under
859 the "dc=example,dc=com" tree, with the second rule allowing
860 also read in the "ou=People" subtree,
861 or the (even more silly) example
862 .LP
863 .nf
864 access to dn.subtree="dc=example,dc=com" attrs=cn
865 by * =cs continue
866 by users +r
867 .fi
868 .LP
869 which grants everybody search and compare privileges, and adds read
870 privileges to authenticated clients.
871 .LP
872 One useful application is to easily grant write privileges to an
873 .B updatedn
874 that is different from the
875 .BR rootdn .
876 In this case, since the
877 .B updatedn
878 needs write access to (almost) all data, one can use
879 .LP
880 .nf
881 access to *
882 by dn.exact="cn=The Update DN,dc=example,dc=com" write
883 by * break
884 .fi
885 .LP
886 as the first access rule.
887 As a consequence, unless the operation is performed with the
888 .B updatedn
889 identity, control is passed straight to the subsequent rules.
891 .SH OPERATION REQUIREMENTS
892 Operations require different privileges on different portions of entries.
893 The following summary applies to primary database backends such as
894 the BDB and HDB backends. Requirements for other backends may
895 (and often do) differ.
897 .LP
898 The
899 .B add
900 operation requires
901 .B add (=a)
902 privileges on the pseudo-attribute
903 .B entry
904 of the entry being added, and
905 .B add (=a)
906 privileges on the pseudo-attribute
907 .B children
908 of the entry's parent.
909 When adding the suffix entry of a database,
910 .B add
911 access to
912 .B children
913 of the empty DN ("") is required.
915 .LP
916 The
917 .B bind
918 operation, when credentials are stored in the directory, requires
919 .B auth (=x)
920 privileges on the attribute the credentials are stored in (usually
921 .BR userPassword ).
923 .LP
924 The
925 .B compare
926 operation requires
927 .B compare (=c)
928 privileges on the attribute that is being compared.
930 .LP
931 The
932 .B delete
933 operation requires
934 .B delete (=z)
935 privileges on the pseudo-attribute
936 .B entry
937 of the entry being deleted, and
938 .B delete (=d)
939 privileges on the
940 .B children
941 pseudo-attribute of the entry's parent.
943 .LP
944 The
945 .B modify
946 operation requires
947 .B write (=w)
948 privileges on the attributes being modified.
949 In detail,
950 .B add (=a)
951 is required to add new values,
952 .B delete (=z)
953 is required to delete existing values,
954 and both
955 .B delete
956 and
957 .BR "add (=az)" ,
958 or
959 .BR "write (=w)" ,
960 are required to replace existing values.
962 .LP
963 The
964 .B modrdn
965 operation requires
966 .B write (=w)
967 privileges on the pseudo-attribute
968 .B entry
969 of the entry whose relative DN is being modified,
970 .B delete (=z)
971 privileges on the pseudo-attribute
972 .B children
973 of the old entry's parents,
974 .B add (=a)
975 privileges on the pseudo-attribute
976 .B children
977 of the new entry's parents, and
978 .B add (=a)
979 privileges on the attributes that are present in the new relative DN.
980 .B Delete (=z)
981 privileges are also required on the attributes that are present
982 in the old relative DN if
983 .B deleteoldrdn
984 is set to 1.
986 .LP
987 The
988 .B search
989 operation, requires
990 .B search (=s)
991 privileges on the
992 .B entry
993 pseudo-attribute of the searchBase
994 (NOTE: this was introduced with OpenLDAP 2.4).
995 Then, for each entry, it requires
996 .B search (=s)
997 privileges on the attributes that are defined in the filter.
998 The resulting entries are finally tested for
999 .B read (=r)
1000 privileges on the pseudo-attribute
1001 .B entry
1002 (for read access to the entry itself)
1003 and for
1004 .B read (=r)
1005 access on each value of each attribute that is requested.
1006 Also, for each
1007 .B referral
1008 object used in generating continuation references, the operation requires
1009 .B read (=r)
1010 access on the pseudo-attribute
1011 .B entry
1012 (for read access to the referral object itself),
1013 as well as
1014 .B read (=r)
1015 access to the attribute holding the referral information
1016 (generally the
1017 .B ref
1018 attribute).
1020 .LP
1021 Some internal operations and some
1022 .B controls
1023 require specific access privileges.
1024 The
1025 .B authzID
1026 mapping and the
1027 .B proxyAuthz
1028 control require
1029 .B auth (=x)
1030 privileges on all the attributes that are present in the search filter
1031 of the URI regexp maps (the right-hand side of the
1032 .B authz-regexp
1033 directives).
1034 .B Auth (=x)
1035 privileges are also required on the
1036 .B authzTo
1037 attribute of the authorizing identity and/or on the
1038 .B authzFrom
1039 attribute of the authorized identity.
1040 In general, when an internal lookup is performed for authentication
1041 or authorization purposes, search-specific privileges (see the access
1042 requirements for the search operation illustrated above) are relaxed to
1043 .BR auth .
1045 .LP
1046 Access control to search entries is checked by the frontend,
1047 so it is fully honored by all backends; for all other operations
1048 and for the discovery phase of the search operation,
1049 full ACL semantics is only supported by the primary backends, i.e.
1050 .BR back-bdb (5),
1051 and
1052 .BR back-hdb (5).
1054 Some other backend, like
1055 .BR back-sql (5),
1056 may fully support them; others may only support a portion of the
1057 described semantics, or even differ in some aspects.
1058 The relevant details are described in the backend-specific man pages.
1060 .SH CAVEATS
1061 It is strongly recommended to explicitly use the most appropriate
1062 .B <dnstyle>
1063 in
1064 .B <what>
1065 and
1066 .B <who>
1067 clauses, to avoid possible incorrect specifications of the access rules
1068 as well as for performance (avoid unnecessary regex matching when an exact
1069 match suffices) reasons.
1070 .LP
1071 An administrator might create a rule of the form:
1072 .LP
1073 .nf
1074 access to dn.regex="dc=example,dc=com"
1075 by ...
1076 .fi
1077 .LP
1078 expecting it to match all entries in the subtree "dc=example,dc=com".
1079 However, this rule actually matches any DN which contains anywhere
1080 the substring "dc=example,dc=com". That is, the rule matches both
1081 "uid=joe,dc=example,dc=com" and "dc=example,dc=com,uid=joe".
1082 .LP
1083 To match the desired subtree, the rule would be more precisely
1084 written:
1085 .LP
1086 .nf
1087 access to dn.regex="^(.+,)?dc=example,dc=com$"
1088 by ...
1089 .fi
1090 .LP
1091 For performance reasons, it would be better to use the subtree style.
1092 .LP
1093 .nf
1094 access to dn.subtree="dc=example,dc=com"
1095 by ...
1096 .fi
1097 .LP
1098 When writing submatch rules, it may be convenient to avoid unnecessary
1099 .B regex
1100 .B <dnstyle>
1101 use; for instance, to allow access to the subtree of the user
1102 that matches the
1103 .B <what>
1104 clause, one could use
1105 .LP
1106 .nf
1107 access to dn.regex="^(.+,)?uid=([^,]+),dc=example,dc=com$"
1108 by dn.regex="^uid=$2,dc=example,dc=com$$" write
1109 by ...
1110 .fi
1111 .LP
1112 However, since all that is required in the
1113 .B <by>
1114 clause is substring expansion, a more efficient solution is
1115 .LP
1116 .nf
1117 access to dn.regex="^(.+,)?uid=([^,]+),dc=example,dc=com$"
1118 by dn.exact,expand="uid=$2,dc=example,dc=com" write
1119 by ...
1120 .fi
1121 .LP
1122 In fact, while a
1123 .B <dnstyle>
1124 of
1125 .B regex
1126 implies substring expansion,
1127 .BR exact ,
1128 as well as all the other DN specific
1129 .B <dnstyle>
1130 values, does not, so it must be explicitly requested.
1131 .LP
1132 .SH FILES
1133 .TP
1134 /etc/openldap/slapd.conf
1135 default slapd configuration file
1136 .SH SEE ALSO
1137 .BR slapd (8),
1138 .BR slapd-* (5),
1139 .BR slapacl (8),
1140 .BR regex (7),
1141 .BR re_format (7)
1142 .LP
1143 "OpenLDAP Administrator's Guide" (http://www.OpenLDAP.org/doc/admin/)
1144 .SH ACKNOWLEDGEMENTS
1145 .\" Shared Project Acknowledgement Text
1146 .B "OpenLDAP Software"
1147 is developed and maintained by The OpenLDAP Project <http://www.openldap.org/>.
1148 .B "OpenLDAP Software"
1149 is derived from University of Michigan LDAP 3.3 Release.