1SLAPD-META(5) File Formats Manual SLAPD-META(5)
2
6 slapd-meta - metadirectory backend
7
9 /etc/openldap/slapd.conf
10
12 The meta backend to slapd(8) performs basic LDAP proxying with respect
13 to a set of remote LDAP servers, called "targets". The information
14 contained in these servers can be presented as belonging to a single
15 Directory Information Tree (DIT).
16 A basic knowledge of the functionality of the slapd-ldap(5) backend is
18 recommended. This backend has been designed as an enhancement of the
19 ldap backend. The two backends share many features (actually they also
20 share portions of code). While the ldap backend is intended to proxy
21 operations directed to a single server, the meta backend is mainly
22 intended for proxying of multiple servers and possibly naming context
23 masquerading. These features, although useful in many scenarios, may
24 result in excessive overhead for some applications, so its use should
25 be carefully considered. In the examples section, some typical scenar‐
26 ios will be discussed.
27 Note: When looping back to the same instance of slapd(8), each connec‐
30 tion requires a new thread; as a consequence, slapd(8) must be compiled
31 with thread support, and the threads parameter may need some tuning; in
32 those cases, unless the multiple target feature is required, one may
33 consider using slapd-relay(5) instead, which performs the relayed oper‐
34 ation internally and thus reuses the same connection.
35
38 There are examples in various places in this document, as well as in
39 the slapd/back-meta/data/ directory in the OpenLDAP source tree.
40
42 These slapd.conf options apply to the META backend database. That is,
43 they must follow a "database meta" line and come before any subsequent
44 "backend" or "database" lines. Other database options are described in
45 the slapd.conf(5) manual page.
46 Note: In early versions of back-ldap and back-meta it was recommended
48 to always set
49 lastmod off
51 for every ldap and meta database. This is because operational
53 attributes related to entry creation and modification should not be
54 proxied, as they could be mistakenly written to the target server(s),
55 generating an error. The current implementation automatically sets
56 lastmod to off, so its use is redundant and should be omitted, because
57 the lastmod directive will be deprecated in the future.
58
61 Target configuration starts with the "uri" directive. All the configu‐
62 ration directives that are not specific to targets should be defined
63 first for clarity, including those that are common to all backends.
64 They are:
65 default-target none
68 This directive forces the backend to reject all those operations
69 that must resolve to a single target in case none or multiple
70 targets are selected. They include: add, delete, modify, mod‐
71 rdn; compare is not included, as well as bind since, as they
72 don't alter entries, in case of multiple matches an attempt is
73 made to perform the operation on any candidate target, with the
74 constraint that at most one must succeed. This directive can
75 also be used when processing targets to mark a specific target
76 as default.
77 dncache-ttl {DISABLED|forever|<ttl>}
80 This directive sets the time-to-live of the DN cache. This
81 caches the target that holds a given DN to speed up target
82 selection in case multiple targets would result from an uncached
83 search; forever means cache never expires; disabled means no DN
84 caching; otherwise a valid ( > 0 ) ttl is required, in the for‐
85 mat illustrated for the idle-timeout directive.
86 conn-ttl <time>
89 This directive causes a cached connection to be dropped an
90 recreated after a given ttl, regardless of being idle or not.
91 onerr {CONTINUE|stop}
94 This directive allows to select the behavior in case an error is
95 returned by one target during a search. The default, continue,
96 consists in continuing the operation, trying to return as much
97 data as possible. If this statement is set to stop, the search
98 is terminated as soon as an error is returned by one target, and
99 the error is immediately propagated to the client.
100 protocol-version {0,2,3}
103 This directive indicates what protocol version must be used to
104 contact the remote server. If set to 0 (the default), the proxy
105 uses the same protocol version used by the client, otherwise the
106 requested protocol is used. The proxy returns unwillingToPer‐
107 form if an operation that is incompatible with the requested
108 protocol is attempted. If set before any target specification,
109 it affects all targets, unless overridden by any per-target
110 directive.
111 pseudoroot-bind-defer {NO|yes}
114 This directive, when set to yes, causes the authentication to
115 the remote servers with the pseudo-root identity to be deferred
116 until actually needed by subsequent operations.
117 rebind-as-user {NO|yes}
120 If this option is given, the client's bind credentials are
121 remembered for rebinds, when trying to re-establish a broken
122 connection, or when chasing a referral, if chase-referrals is
123 set to yes.
124
127 Target specification starts with a "uri" directive:
128 uri <protocol>://[<host>[:<port>]]/<naming context>
131 The "server" directive that was allowed in the LDAP backend
132 (although deprecated) has been completely discarded in the Meta
133 backend. The <protocol> part can be anything ldap_initialize(3)
134 accepts ({ldap|ldaps|ldapi} and variants); <host> and <port> may
135 be omitted, defaulting to whatever is set in ldap.conf(5). The
136 <naming context> part is mandatory. It must end with one of the
137 naming contexts defined for the backend, e.g.:
138 suffix "dc=foo,dc=com"
140 uri "ldap://x.foo.com/dc=x,dc=foo,dc=com"
141 The <naming context> part doesn't need to be unique across the
143 targets; it may also match one of the values of the "suffix"
144 directive. Multiple URIs may be defined in a single argument.
145 The URIs must be separated by TABs (e.g. '\t'; commas or spaces,
146 unlike back-ldap, will not work, because they are legal in the
147 <naming context>, and we don't want to use URL-encoded <naming
148 context>s), and the additional URIs must have no <naming con‐
149 text> part. This causes the underlying library to contact the
150 first server of the list that responds. For example, if
151 l1.foo.com and l2.foo.com are shadows of the same server, the
152 directive
153 suffix "dc=foo,dc=com"
155 uri "ldap://l1.foo.com/dc=foo,dc=com ldap://l2.foo.com/"
156 causes l2.foo.com to be contacted whenever l1.foo.com does not
158 respond.
159 acl-authcDN <administrative DN for access control purposes>
162 DN which is used to query the target server for acl checking, as
163 in the LDAP backend; it is supposed to have read access on the
164 target server to attributes used on the proxy for acl checking.
165 There is no risk of giving away such values; they are only used
166 to check permissions. The acl-authcDN identity is by no means
167 implicitly used by the proxy when the client connects anony‐
168 mously.
169 acl-passwd <password>
172 Password used with the acl-authcDN above.
173 bind-timeout <microseconds>
176 This directive defines the timeout, in microseconds, used when
177 polling for response after an asynchronous bind connection. The
178 initial call to ldap_result(3) is performed with a trade-off
179 timeout of 100000 us; if that results in a timeout exceeded,
180 subsequent calls use the value provided with bind-timeout. The
181 default value is used also for subsequent calls if bind-timeout
182 is not specified. If set before any target specification, it
183 affects all targets, unless overridden by any per-target direc‐
184 tive.
185 chase-referrals {YES|no}
188 enable/disable automatic referral chasing, which is delegated to
189 the underlying libldap, with rebinding eventually performed if
190 the rebind-as-user directive is used. The default is to chase
191 referrals. If set before any target specification, it affects
192 all targets, unless overridden by any per-target directive.
193 default-target [<target>]
196 The "default-target" directive can also be used during target
197 specification. With no arguments it marks the current target as
198 the default. The optional number marks target <target> as the
199 default one, starting from 1. Target <target> must be defined.
200 idle-timeout <time>
203 This directive causes a cached connection to be dropped an
204 recreated after it has been idle for the specified time. The
205 value can be specified as
206 [<d>d][<h>h][<m>m][<s>[s]]
208 where <d>, <h>, <m> and <s> are respectively treated as days,
210 hours, minutes and seconds. If set before any target specifica‐
211 tion, it affects all targets, unless overridden by any per-tar‐
212 get directive.
213 map {attribute|objectclass} [<local name>|*] {<foreign name>|*}
216 This maps object classes and attributes as in the LDAP backend.
217 See slapd-ldap(5).
218 network-timeout <time>
221 Sets the network timeout value after which poll(2)/select(2)
222 following a connect(2) returns in case of no activity. The
223 value is in seconds, and it can be specified as for idle-time‐
224 out. If set before any target specification, it affects all
225 targets, unless overridden by any per-target directive.
226 nretries {forever|never|<nretries>}
229 This directive defines how many times a bind should be retried
230 in case of temporary failure in contacting a target. If defined
231 before any target specification, it applies to all targets (by
232 default, 3 times); the global value can be overridden by redefi‐
233 nitions inside each target specification.
234 pseudorootdn <substitute DN in case of rootdn bind>
237 This directive, if present, sets the DN that will be substituted
238 to the bind DN if a bind with the backend's "rootdn" succeeds.
239 The true "rootdn" of the target server ought not be used; an
240 arbitrary administrative DN should used instead.
241 pseudorootpw <substitute password in case of rootdn bind>
244 This directive sets the credential that will be used in case a
245 bind with the backend's "rootdn" succeeds, and the bind is prop‐
246 agated to the target using the "pseudorootdn" DN.
247 Note: cleartext credentials must be supplied here; as a conse‐
249 quence, using the pseudorootdn/pseudorootpw directives is inher‐
250 ently unsafe.
251 rewrite* ...
254 The rewrite options are described in the "REWRITING" section.
255 subtree-exclude <DN>
258 This directive instructs back-meta to ignore the current target
259 for operations whose requestDN is subordinate to DN. There may
260 be multiple occurrences of the subtree-exclude directive for
261 each of the targets.
262 suffixmassage <virtual naming context> <real naming context>
265 All the directives starting with "rewrite" refer to the rewrite
266 engine that has been added to slapd. The "suffixmassage" direc‐
267 tive was introduced in the LDAP backend to allow suffix massag‐
268 ing while proxying. It has been obsoleted by the rewriting
269 tools. However, both for backward compatibility and for ease of
270 configuration when simple suffix massage is required, it has
271 been preserved. It wraps the basic rewriting instructions that
272 perform suffix massaging. See the "REWRITING" section for a
273 detailed list of the rewrite rules it implies.
274 t-f-support {NO|yes|discover}
277 enable if the remote server supports absolute filters (see
278 draft-zeilenga-ldap-t-f for details). If set to discover, sup‐
279 port is detected by reading the remote server's root DSE. If
280 set before any target specification, it affects all targets,
281 unless overridden by any per-target directive.
282 timeout [{add|delete|modify|modrdn}=]<seconds> [...]
285 This directive allows to set per-database, per-target and per-
286 operation timeouts. If no operation is specified, it affects
287 all. Currently, only write operations are addressed, because
288 searches can already be limited by means of the limits directive
289 (see slapd.conf(5) for details), and other operations are not
290 supposed to incur into the need for timeouts. Note: if the
291 timelimit is exceeded, the operation is abandoned; the protocol
292 does not provide any means to rollback the operation, so the
293 client will not know if the operation eventually succeeded or
294 not. If set before any target specification, it affects all
295 targets, unless overridden by any per-target directive.
296 tls {[try-]start|[try-]propagate}
299 execute the StartTLS extended operation when the connection is
300 initialized; only works if the URI directive protocol scheme is
301 not ldaps://. propagate issues the StartTLS operation only if
302 the original connection did. The try- prefix instructs the
303 proxy to continue operations if the StartTLS operation failed;
304 its use is highly deprecated. If set before any target specifi‐
305 cation, it affects all targets, unless overridden by any per-
306 target directive.
307
310 A powerful (and in some sense dangerous) rewrite engine has been added
311 to both the LDAP and Meta backends. While the former can gain limited
312 beneficial effects from rewriting stuff, the latter can become an amaz‐
313 ingly powerful tool.
314 Consider a couple of scenarios first.
316 1) Two directory servers share two levels of naming context; say
318 "dc=a,dc=foo,dc=com" and "dc=b,dc=foo,dc=com". Then, an unambiguous
319 Meta database can be configured as:
320 database meta
322 suffix "dc=foo,dc=com"
323 uri "ldap://a.foo.com/dc=a,dc=foo,dc=com"
324 uri "ldap://b.foo.com/dc=b,dc=foo,dc=com"
325 Operations directed to a specific target can be easily resolved because
327 there are no ambiguities. The only operation that may resolve to mul‐
328 tiple targets is a search with base "dc=foo,dc=com" and scope at least
329 "one", which results in spawning two searches to the targets.
330 2a) Two directory servers don't share any portion of naming context,
332 but they'd present as a single DIT [Caveat: uniqueness of (massaged)
333 entries among the two servers is assumed; integrity checks risk to
334 incur in excessive overhead and have not been implemented]. Say we
335 have "dc=bar,dc=org" and "o=Foo,c=US", and we'd like them to appear as
336 branches of "dc=foo,dc=com", say "dc=a,dc=foo,dc=com" and
337 "dc=b,dc=foo,dc=com". Then we need to configure our Meta backend as:
338 database meta
340 suffix "dc=foo,dc=com"
341 uri "ldap://a.bar.com/dc=a,dc=foo,dc=com"
343 suffixmassage "dc=a,dc=foo,dc=com" "dc=bar,dc=org"
344 uri "ldap://b.foo.com/dc=b,dc=foo,dc=com"
346 suffixmassage "dc=b,dc=foo,dc=com" "o=Foo,c=US"
347 Again, operations can be resolved without ambiguity, although some
349 rewriting is required. Notice that the virtual naming context of each
350 target is a branch of the database's naming context; it is rewritten
351 back and forth when operations are performed towards the target
352 servers. What "back and forth" means will be clarified later.
353 When a search with base "dc=foo,dc=com" is attempted, if the scope is
355 "base" it fails with "no such object"; in fact, the common root of the
356 two targets (prior to massaging) does not exist. If the scope is
357 "one", both targets are contacted with the base replaced by each tar‐
358 get's base; the scope is derated to "base". In general, a scope "one"
359 search is honored, and the scope is derated, only when the incoming
360 base is at most one level lower of a target's naming context (prior to
361 massaging).
362 Finally, if the scope is "sub" the incoming base is replaced by each
364 target's unmassaged naming context, and the scope is not altered.
365 2b) Consider the above reported scenario with the two servers sharing
367 the same naming context:
368 database meta
370 suffix "dc=foo,dc=com"
371 uri "ldap://a.bar.com/dc=foo,dc=com"
373 suffixmassage "dc=foo,dc=com" "dc=bar,dc=org"
374 uri "ldap://b.foo.com/dc=foo,dc=com"
376 suffixmassage "dc=foo,dc=com" "o=Foo,c=US"
377 All the previous considerations hold, except that now there is no way
379 to unambiguously resolve a DN. In this case, all the operations that
380 require an unambiguous target selection will fail unless the DN is
381 already cached or a default target has been set. Practical configura‐
382 tions may result as a combination of all the above scenarios.
383
385 Note on ACLs: at present you may add whatever ACL rule you desire to to
386 the Meta (and LDAP) backends. However, the meaning of an ACL on a
387 proxy may require some considerations. Two philosophies may be consid‐
388 ered:
389 a) the remote server dictates the permissions; the proxy simply passes
391 back what it gets from the remote server.
392 b) the remote server unveils "everything"; the proxy is responsible for
394 protecting data from unauthorized access.
395 Of course the latter sounds unreasonable, but it is not. It is possi‐
397 ble to imagine scenarios in which a remote host discloses data that can
398 be considered "public" inside an intranet, and a proxy that connects it
399 to the internet may impose additional constraints. To this purpose,
400 the proxy should be able to comply with all the ACL matching criteria
401 that the server supports. This has been achieved with regard to all
402 the criteria supported by slapd except a special subtle case (please
403 drop me a note if you can find other exceptions: <ando@openldap.org>).
404 The rule
405 access to dn="<dn>" attr=<attr>
407 by dnattr=<dnattr> read
408 by * none
409 cannot be matched iff the attribute that is being requested, <attr>, is
411 NOT <dnattr>, and the attribute that determines membership, <dnattr>,
412 has not been requested (e.g. in a search)
413 In fact this ACL is resolved by slapd using the portion of entry it
415 retrieved from the remote server without requiring any further inter‐
416 vention of the backend, so, if the <dnattr> attribute has not been
417 fetched, the match cannot be assessed because the attribute is not
418 present, not because no value matches the requirement!
419 Note on ACLs and attribute mapping: ACLs are applied to the mapped
421 attributes; for instance, if the attribute locally known as "foo" is
422 mapped to "bar" on a remote server, then local ACLs apply to attribute
423 "foo" and are totally unaware of its remote name. The remote server
424 will check permissions for "bar", and the local server will possibly
425 enforce additional restrictions to "foo".
426
428 A string is rewritten according to a set of rules, called a `rewrite
429 context'. The rules are based on POSIX (''extended'') regular expres‐
430 sions (regex) with substring matching; basic variable substitution and
431 map resolution of substrings is allowed by specific mechanisms detailed
432 in the following. The behavior of pattern matching/substitution can be
433 altered by a set of flags.
434 The underlying concept is to build a lightweight rewrite module for the
436 slapd server (initially dedicated to the LDAP backend).
437
439 An incoming string is matched against a set of rules. Rules are made
440 of a regex match pattern, a substitution pattern and a set of actions,
441 described by a set of flags. In case of match a string rewriting is
442 performed according to the substitution pattern that allows to refer to
443 substrings matched in the incoming string. The actions, if any, are
444 finally performed. The substitution pattern allows map resolution of
445 substrings. A map is a generic object that maps a substitution pattern
446 to a value. The flags are divided in "Pattern matching Flags" and
447 "Action Flags"; the former alter the regex match pattern behavior while
448 the latter alter the action that is taken after substitution.
449
451 `C' honors case in matching (default is case insensitive)
452 `R' use POSIX ''basic'' regular expressions (default is
454 ''extended'')
455 `M{n}' allow no more than n recursive passes for a specific rule; does
457 not alter the max total count of passes, so it can only enforce
458 a stricter limit for a specific rule.
459
461 `:' apply the rule once only (default is recursive)
462 `@' stop applying rules in case of match; the current rule is still
464 applied recursively; combine with `:' to apply the current rule
465 only once and then stop.
466 `#' stop current operation if the rule matches, and issue an
468 `unwilling to perform' error.
469 `G{n}' jump n rules back and forth (watch for loops!). Note that
471 `G{1}' is implicit in every rule.
472 `I' ignores errors in rule; this means, in case of error, e.g.
474 issued by a map, the error is treated as a missed match. The
475 `unwilling to perform' is not overridden.
476 `U{n}' uses n as return code if the rule matches; the flag does not
478 alter the recursive behavior of the rule, so, to have it per‐
479 formed only once, it must be used in combination with `:', e.g.
480 `:U{16}' returns the value `16' after exactly one execution of
481 the rule, if the pattern matches. As a consequence, its behav‐
482 ior is equivalent to `@', with the return code set to n; or, in
483 other words, `@' is equivalent to `U{0}'. By convention, the
484 freely available codes are above 16 included; the others are
485 reserved.
486 The ordering of the flags can be significant. For instance: `IG{2}'
488 means ignore errors and jump two lines ahead both in case of match and
489 in case of error, while `G{2}I' means ignore errors, but jump two lines
490 ahead only in case of match.
491 More flags (mainly Action Flags) will be added as needed.
493
495 See regex(7) and/or re_format(7).
496
498 Everything starting with `%' requires substitution;
499 the only obvious exception is `%%', which is left as is;
501 the basic substitution is `%d', where `d' is a digit; 0 means the whole
503 string, while 1-9 is a submatch;
504 a `%' followed by a `{' invokes an advanced substitution. The pattern
506 is:
507 `%' `{' [ <op> ] <name> `(' <substitution> `)' `}'
509 where <name> must be a legal name for the map, i.e.
511 <name> ::= [a-z][a-z0-9]* (case insensitive)
513 <op> ::= `>' `|' `&' `&&' `*' `**' `$'
514 and <substitution> must be a legal substitution pattern, with no limits
516 on the nesting level.
517 The operators are:
519 > sub context invocation; <name> must be a legal, already defined
521 rewrite context name
522 | external command invocation; <name> must refer to a legal,
524 already defined command name (NOT IMPL.)
525 & variable assignment; <name> defines a variable in the running
527 operation structure which can be dereferenced later; operator &
528 assigns a variable in the rewrite context scope; operator &&
529 assigns a variable that scopes the entire session, e.g. its
530 value can be dereferenced later by other rewrite contexts
531 * variable dereferencing; <name> must refer to a variable that is
533 defined and assigned for the running operation; operator *
534 dereferences a variable scoping the rewrite context; operator **
535 dereferences a variable scoping the whole session, e.g. the
536 value is passed across rewrite contexts
537 $ parameter dereferencing; <name> must refer to an existing param‐
539 eter; the idea is to make some run-time parameters set by the
540 system available to the rewrite engine, as the client host name,
541 the bind DN if any, constant parameters initialized at config
542 time, and so on; no parameter is currently set by either
543 back-ldap or back-meta, but constant parameters can be defined
544 in the configuration file by using the rewriteParam directive.
545 Substitution escaping has been delegated to the `%' symbol, which is
547 used instead of `\' in string substitution patterns because `\' is
548 already escaped by slapd's low level parsing routines; as a conse‐
549 quence, regex escaping requires two `\' symbols, e.g. `.*\.foo\.bar'
550 must be written as `.*\\.foo\\.bar'.
551
553 A rewrite context is a set of rules which are applied in sequence. The
554 basic idea is to have an application initialize a rewrite engine (think
555 of Apache's mod_rewrite ...) with a set of rewrite contexts; when
556 string rewriting is required, one invokes the appropriate rewrite con‐
557 text with the input string and obtains the newly rewritten one if no
558 errors occur.
559 Each basic server operation is associated to a rewrite context; they
561 are divided in two main groups: client -> server and server -> client
562 rewriting.
563 client -> server:
565 (default) if defined and no specific context
567 is available
568 bindDN bind
569 searchBase search
570 searchFilter search
571 searchFilterAttrDN search
572 compareDN compare
573 compareAttrDN compare AVA
574 addDN add
575 addAttrDN add AVA
576 modifyDN modify
577 modifyAttrDN modify AVA
578 modrDN modrdn
579 newSuperiorDN modrdn
580 deleteDN delete
581 exopPasswdDN password modify extended operation DN if proxy
582 server -> client:
584 searchResult search (only if defined; no default;
586 acts on DN and DN-syntax attributes
587 of search results)
588 searchAttrDN search AVA
589 matchedDN all ops (only if applicable)
590
592 rewriteEngine { on | off }
593 If `on', the requested rewriting is performed; if `off', no
594 rewriting takes place (an easy way to stop rewriting without
595 altering too much the configuration file).
596 rewriteContext <context name> [ alias <aliased context name> ]
598 <Context name> is the name that identifies the context, i.e. the
599 name used by the application to refer to the set of rules it
600 contains. It is used also to reference sub contexts in string
601 rewriting. A context may alias another one. In this case the
602 alias context contains no rule, and any reference to it will
603 result in accessing the aliased one.
604 rewriteRule <regex match pattern> <substitution pattern> [ <flags> ]
606 Determines how a string can be rewritten if a pattern is
607 matched. Examples are reported below.
608
610 rewriteMap <map type> <map name> [ <map attrs> ]
611 Allows to define a map that transforms substring rewriting into
612 something else. The map is referenced inside the substitution
613 pattern of a rule.
614 rewriteParam <param name> <param value>
616 Sets a value with global scope, that can be dereferenced by the
617 command `%{$paramName}'.
618 rewriteMaxPasses <number of passes> [<number of passes per rule>]
620 Sets the maximum number of total rewriting passes that can be
621 performed in a single rewrite operation (to avoid loops). A
622 safe default is set to 100; note that reaching this limit is
623 still treated as a success; recursive invocation of rules is
624 simply interrupted. The count applies to the rewriting opera‐
625 tion as a whole, not to any single rule; an optional per-rule
626 limit can be set. This limit is overridden by setting specific
627 per-rule limits with the `M{n}' flag.
628
630 # set to `off' to disable rewriting
631 rewriteEngine on
632 # the rules the "suffixmassage" directive implies
634 rewriteEngine on
635 # all dataflow from client to server referring to DNs
636 rewriteContext default
637 rewriteRule "(.*)<virtualnamingcontext>$" "%1<realnamingcontext>" ":"
638 # empty filter rule
639 rewriteContext searchFilter
640 # all dataflow from server to client
641 rewriteContext searchResult
642 rewriteRule "(.*)<realnamingcontext>$" "%1<virtualnamingcontext>" ":"
643 rewriteContext searchAttrDN alias searchResult
644 rewriteContext matchedDN alias searchResult
645 # Everything defined here goes into the `default' context.
647 # This rule changes the naming context of anything sent
648 # to `dc=home,dc=net' to `dc=OpenLDAP, dc=org'
649 rewriteRule "(.*)dc=home,[ ]?dc=net"
651 "%1dc=OpenLDAP, dc=org" ":"
652 # since a pretty/normalized DN does not include spaces
654 # after rdn separators, e.g. `,', this rule suffices:
655 rewriteRule "(.*)dc=home,dc=net"
657 "%1dc=OpenLDAP,dc=org" ":"
658 # Start a new context (ends input of the previous one).
660 # This rule adds blanks between DN parts if not present.
661 rewriteContext addBlanks
662 rewriteRule "(.*),([^ ].*)" "%1, %2"
663 # This one eats blanks
665 rewriteContext eatBlanks
666 rewriteRule "(.*),[ ](.*)" "%1,%2"
667 # Here control goes back to the default rewrite
669 # context; rules are appended to the existing ones.
670 # anything that gets here is piped into rule `addBlanks'
671 rewriteContext default
672 rewriteRule ".*" "%{>addBlanks(%0)}" ":"
673 # Rewrite the search base according to `default' rules.
675 rewriteContext searchBase alias default
676 # Search results with OpenLDAP DN are rewritten back with
678 # `dc=home,dc=net' naming context, with spaces eaten.
679 rewriteContext searchResult
680 rewriteRule "(.*[^ ]?)[ ]?dc=OpenLDAP,[ ]?dc=org"
681 "%{>eatBlanks(%1)}dc=home,dc=net" ":"
682 # Bind with email instead of full DN: we first need
684 # an ldap map that turns attributes into a DN (the
685 # argument used when invoking the map is appended to
686 # the URI and acts as the filter portion)
687 rewriteMap ldap attr2dn "ldap://host/dc=my,dc=org?dn?sub"
688 # Then we need to detect DN made up of a single email,
690 # e.g. `mail=someone@example.com'; note that the rule
691 # in case of match stops rewriting; in case of error,
692 # it is ignored. In case we are mapping virtual
693 # to real naming contexts, we also need to rewrite
694 # regular DNs, because the definition of a bindDn
695 # rewrite context overrides the default definition.
696 rewriteContext bindDN
697 rewriteRule "^mail=[^,]+@[^,]+$" "%{attr2dn(%0)}" ":@I"
698 # This is a rather sophisticated example. It massages a
700 # search filter in case who performs the search has
701 # administrative privileges. First we need to keep
702 # track of the bind DN of the incoming request, which is
703 # stored in a variable called `binddn' with session scope,
704 # and left in place to allow regular binding:
705 rewriteContext bindDN
706 rewriteRule ".+" "%{&&binddn(%0)}%0" ":"
707 # A search filter containing `uid=' is rewritten only
709 # if an appropriate DN is bound.
710 # To do this, in the first rule the bound DN is
711 # dereferenced, while the filter is decomposed in a
712 # prefix, in the value of the `uid=<arg>' AVA, and
713 # in a suffix. A tag `<>' is appended to the DN.
714 # If the DN refers to an entry in the `ou=admin' subtree,
715 # the filter is rewritten OR-ing the `uid=<arg>' with
716 # `cn=<arg>'; otherwise it is left as is. This could be
717 # useful, for instance, to allow apache's auth_ldap-1.4
718 # module to authenticate users with both `uid' and
719 # `cn', but only if the request comes from a possible
720 # `cn=Web auth,ou=admin,dc=home,dc=net' user.
721 rewriteContext searchFilter
722 rewriteRule "(.*\\()uid=([a-z0-9_]+)(\\).*)"
723 "%{**binddn}<>%{&prefix(%1)}%{&arg(%2)}%{&suffix(%3)}"
724 ":I"
725 rewriteRule "[^,]+,ou=admin,dc=home,dc=net"
726 "%{*prefix}|(uid=%{*arg})(cn=%{*arg})%{*suffix}" ":@I"
727 rewriteRule ".*<>" "%{*prefix}uid=%{*arg}%{*suffix}" ":"
728 # This example shows how to strip unwanted DN-valued
730 # attribute values from a search result; the first rule
731 # matches DN values below "ou=People,dc=example,dc=com";
732 # in case of match the rewriting exits successfully.
733 # The second rule matches everything else and causes
734 # the value to be rejected.
735 rewriteContext searchResult
736 rewriteRule ".*,ou=People,dc=example,dc=com" "%0" ":@"
737 rewriteRule ".*" "" "#"
738
740 In case the rewritten DN is an LDAP URI, the operation is initiated
741 towards the host[:port] indicated in the uri, if it does not refer to
742 the local server. E.g.:
743 rewriteRule '^cn=root,.*' '%0' 'G{3}'
745 rewriteRule '^cn=[a-l].*' 'ldap://ldap1.my.org/%0' ':@'
746 rewriteRule '^cn=[m-z].*' 'ldap://ldap2.my.org/%0' ':@'
747 rewriteRule '.*' 'ldap://ldap3.my.org/%0' ':@'
748 (Rule 1 is simply there to illustrate the `G{n}' action; it could have
750 been written:
751 rewriteRule '^cn=root,.*' 'ldap://ldap3.my.org/%0' ':@'
753 with the advantage of saving one rewrite pass ...)
755
758 The meta backend does not honor all ACL semantics as described in
759 slapd.access(5). In general, access checking is delegated to the
760 remote server(s). Only read (=r) access to the entry pseudo-attribute
761 and to the other attribute values of the entries returned by the search
762 operation is honored, which is performed by the frontend.
763
766 The proxy cache overlay allows caching of LDAP search requests
767 (queries) in a local database. See slapo-pcache(5) for details.
768
770 /etc/openldap/slapd.conf
771 default slapd configuration file
772
774 slapd.conf(5), slapd-ldap(5), slapo-pcache(5), slapd(8), regex(7),
775 re_format(7).
776
778 Pierangelo Masarati, based on back-ldap by Howard Chu
779OpenLDAP 2.3.34 2007/2/16 SLAPD-META(5)