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23 <modulesynopsis metafile="mod_authnz_ldap.xml.meta">
25 <name>mod_authnz_ldap</name>
26 <description>Allows an LDAP directory to be used to store the database
27 for HTTP Basic authentication.</description>
28 <status>Extension</status>
29 <sourcefile>mod_authnz_ldap.c</sourcefile>
30 <identifier>authnz_ldap_module</identifier>
31 <compatibility>Available in version 2.1 and later</compatibility>
34 <p>This module provides authentication front-ends such as
35 <module>mod_auth_basic</module> to authenticate users through
36 an ldap directory.</p>
38 <p><module>mod_authnz_ldap</module> supports the following features:</p>
41 <li>Known to support the <a
42 href="http://www.openldap.org/">OpenLDAP SDK</a> (both 1.x
43 and 2.x), <a href="http://developer.novell.com/ndk/cldap.htm">
44 Novell LDAP SDK</a> and the <a
45 href="http://www.iplanet.com/downloads/developer/">iPlanet
46 (Netscape)</a> SDK.</li>
48 <li>Complex authorization policies can be implemented by
49 representing the policy with LDAP filters.</li>
51 <li>Uses extensive caching of LDAP operations via <a
52 href="mod_ldap.html">mod_ldap</a>.</li>
54 <li>Support for LDAP over SSL (requires the Netscape SDK) or
55 TLS (requires the OpenLDAP 2.x SDK or Novell LDAP SDK).</li>
58 <p>When using <module>mod_auth_basic</module>, this module is invoked
59 via the <directive module="mod_auth_basic">AuthBasicProvider</directive>
60 directive with the <code>ldap</code> value.</p>
63 <seealso><module>mod_ldap</module></seealso>
64 <seealso><module>mod_auth_basic</module></seealso>
65 <seealso><module>mod_authz_user</module></seealso>
66 <seealso><module>mod_authz_groupfile</module></seealso>
68 <section id="contents"><title>Contents</title>
72 <a href="#operation">Operation</a>
75 <li><a href="#authenphase">The Authentication
78 <li><a href="#authorphase">The Authorization
84 <a href="#requiredirectives">The Require Directives</a>
87 <li><a href="#reqvaliduser">Require valid-user</a></li>
88 <li><a href="#requser">Require ldap-user</a></li>
89 <li><a href="#reqgroup">Require ldap-group</a></li>
90 <li><a href="#reqdn">Require ldap-dn</a></li>
91 <li><a href="#reqattribute">Require ldap-attribute</a></li>
92 <li><a href="#reqfilter">Require ldap-filter</a></li>
96 <li><a href="#examples">Examples</a></li>
97 <li><a href="#usingtls">Using TLS</a></li>
98 <li><a href="#usingssl">Using SSL</a></li>
99 <li><a href="#exposed">Exposing Login Information</a></li>
100 <li><a href="#activedirectory">Using Active Directory</a></li>
102 <a href="#frontpage">Using Microsoft FrontPage with
103 <module>mod_authnz_ldap</module></a>
106 <li><a href="#howitworks">How It Works</a></li>
107 <li><a href="#fpcaveats">Caveats</a></li>
113 <section id="operation"><title>Operation</title>
115 <p>There are two phases in granting access to a user. The first
116 phase is authentication, in which the <module>mod_authnz_ldap</module>
117 authentication provider verifies that the user's credentials are valid.
118 This is also called the <em>search/bind</em> phase. The second phase is
119 authorization, in which <module>mod_authnz_ldap</module> determines
120 if the authenticated user is allowed access to the resource in
121 question. This is also known as the <em>compare</em>
124 <p><module>mod_authnz_ldap</module> registers both an authn_ldap authentication
125 provider and an authz_ldap authorization handler. The authn_ldap
126 authentication provider can be enabled through the
127 <directive module="mod_auth_basic">AuthBasicProvider</directive> directive
128 using the <code>ldap</code> value. The authz_ldap handler extends the
129 <directive module="mod_authz_core">Require</directive> directive's authorization types
130 by adding <code>ldap-user</code>, <code>ldap-dn</code> and <code>ldap-group</code>
133 <section id="authenphase"><title>The Authentication
136 <p>During the authentication phase, <module>mod_authnz_ldap</module>
137 searches for an entry in the directory that matches the username
138 that the HTTP client passes. If a single unique match is found,
139 then <module>mod_authnz_ldap</module> attempts to bind to the
140 directory server using the DN of the entry plus the password
141 provided by the HTTP client. Because it does a search, then a
142 bind, it is often referred to as the search/bind phase. Here are
143 the steps taken during the search/bind phase.</p>
146 <li>Generate a search filter by combining the attribute and
147 filter provided in the <directive module="mod_authnz_ldap"
148 >AuthLDAPURL</directive> directive with
149 the username passed by the HTTP client.</li>
151 <li>Search the directory using the generated filter. If the
152 search does not return exactly one entry, deny or decline
155 <li>Fetch the distinguished name of the entry retrieved from
156 the search and attempt to bind to the LDAP server using the
157 DN and the password passed by the HTTP client. If the bind is
158 unsuccessful, deny or decline access.</li>
161 <p>The following directives are used during the search/bind
165 <columnspec><column width=".3"/><column width=".7"/></columnspec>
167 <td><directive module="mod_authnz_ldap">AuthLDAPURL</directive></td>
169 <td>Specifies the LDAP server, the
170 base DN, the attribute to use in the search, as well as the
171 extra search filter to use.</td>
175 <td><directive module="mod_authnz_ldap">AuthLDAPBindDN</directive></td>
177 <td>An optional DN to bind with
178 during the search phase.</td>
183 module="mod_authnz_ldap">AuthLDAPBindPassword</directive></td>
185 <td>An optional password to bind
186 with during the search phase.</td>
191 <section id="authorphase"><title>The Authorization Phase</title>
193 <p>During the authorization phase, <module>mod_authnz_ldap</module>
194 attempts to determine if the user is authorized to access the
195 resource. Many of these checks require
196 <module>mod_authnz_ldap</module> to do a compare operation on the
197 LDAP server. This is why this phase is often referred to as the
198 compare phase. <module>mod_authnz_ldap</module> accepts the
199 following <directive module="mod_authz_core">Require</directive>
200 directives to determine if the credentials are acceptable:</p>
203 <li>Grant access if there is a <a
204 href="#reqgroup"><code>Require ldap-user</code></a> directive, and the
205 username in the directive matches the username passed by the
208 <li>Grant access if there is a <a href="#reqdn"><code>Require
209 ldap-dn</code></a> directive, and the DN in the directive matches
210 the DN fetched from the LDAP directory.</li>
212 <li>Grant access if there is a <a
213 href="#reqgroup"><code>Require ldap-group</code></a> directive, and
214 the DN fetched from the LDAP directory (or the username
215 passed by the client) occurs in the LDAP group or, potentially, in
216 one of its sub-groups.</li>
218 <li>Grant access if there is a <a href="#reqattribute">
219 <code>Require ldap-attribute</code></a>
220 directive, and the attribute fetched from the LDAP directory
221 matches the given value.</li>
223 <li>Grant access if there is a <a href="#reqfilter">
224 <code>Require ldap-filter</code></a>
225 directive, and the search filter successfully finds a single user
226 object that matches the dn of the authenticated user.</li>
228 <li>otherwise, deny or decline access</li>
231 <p>Other <directive module="mod_authz_core">Require</directive> values may also
232 be used which may require loading additional authorization modules.</p>
235 <li>Grant access if there is a <a href="#requser"><code>Require
236 valid-user</code></a> directive. (requires
237 <module>mod_authz_user</module>)</li>
239 <li>Grant access if there is a <a
240 href="#reqgroup"><code>Require group</code></a> directive, and
241 <module>mod_authz_groupfile</module> has been loaded with the
242 <directive module="mod_authz_groupfile">AuthGroupFile</directive>
249 <p><module>mod_authnz_ldap</module> uses the following directives during the
253 <columnspec><column width=".4"/><column width=".6"/></columnspec>
255 <td><directive module="mod_authnz_ldap">AuthLDAPURL</directive> </td>
257 <td>The attribute specified in the
258 URL is used in compare operations for the <code>Require
259 ldap-user</code> operation.</td>
264 module="mod_authnz_ldap">AuthLDAPCompareDNOnServer</directive></td>
266 <td>Determines the behavior of the
267 <code>Require ldap-dn</code> directive.</td>
272 module="mod_authnz_ldap">AuthLDAPGroupAttribute</directive></td>
274 <td>Determines the attribute to
275 use for comparisons in the <code>Require ldap-group</code>
281 module="mod_authnz_ldap">AuthLDAPGroupAttributeIsDN</directive></td>
283 <td>Specifies whether to use the
284 user DN or the username when doing comparisons for the
285 <code>Require ldap-group</code> directive.</td>
290 module="mod_authnz_ldap">AuthLDAPMaxSubGroupDepth</directive></td>
292 <td>Determines the maximum depth of sub-groups that will be evaluated
293 during comparisons in the <code>Require ldap-group</code> directive.</td>
298 module="mod_authnz_ldap">AuthLDAPSubGroupAttribute</directive></td>
300 <td>Determines the attribute to use when obtaining sub-group members
301 of the current group during comparisons in the <code>Require ldap-group</code>
307 module="mod_authnz_ldap">AuthLDAPSubGroupClass</directive></td>
309 <td>Specifies the LDAP objectClass values used to identify if queried directory
310 objects really are group objects (as opposed to user objects) during the
311 <code>Require ldap-group</code> directive's sub-group processing.</td>
317 <section id="requiredirectives"><title>The Require Directives</title>
319 <p>Apache's <directive module="mod_authz_core">Require</directive>
320 directives are used during the authorization phase to ensure that
321 a user is allowed to access a resource. mod_authnz_ldap extends the
322 authorization types with <code>ldap-user</code>, <code>ldap-dn</code>,
323 <code>ldap-group</code>, <code>ldap-attribute</code> and
324 <code>ldap-filter</code>. Other authorization types may also be
325 used but may require that additional authorization modules be loaded.</p>
327 <section id="reqvaliduser"><title>Require valid-user</title>
329 <p>If this directive exists, <module>mod_authnz_ldap</module> grants
330 access to any user that has successfully authenticated during the
331 search/bind phase. Requires that <module>mod_authz_user</module> be
335 <section id="requser"><title>Require ldap-user</title>
337 <p>The <code>Require ldap-user</code> directive specifies what
338 usernames can access the resource. Once
339 <module>mod_authnz_ldap</module> has retrieved a unique DN from the
340 directory, it does an LDAP compare operation using the username
341 specified in the <code>Require ldap-user</code> to see if that username
342 is part of the just-fetched LDAP entry. Multiple users can be
343 granted access by putting multiple usernames on the line,
344 separated with spaces. If a username has a space in it, then it
345 must be surrounded with double quotes. Multiple users can also be
346 granted access by using multiple <code>Require ldap-user</code>
347 directives, with one user per line. For example, with a <directive
348 module="mod_authnz_ldap">AuthLDAPURL</directive> of
349 <code>ldap://ldap/o=Airius?cn</code> (i.e., <code>cn</code> is
350 used for searches), the following Require directives could be used
351 to restrict access:</p>
353 Require ldap-user "Barbara Jenson"<br />
354 Require ldap-user "Fred User"<br />
355 Require ldap-user "Joe Manager"<br />
358 <p>Because of the way that <module>mod_authnz_ldap</module> handles this
359 directive, Barbara Jenson could sign on as <em>Barbara
360 Jenson</em>, <em>Babs Jenson</em> or any other <code>cn</code> that
361 she has in her LDAP entry. Only the single <code>Require
362 ldap-user</code> line is needed to support all values of the attribute
363 in the user's entry.</p>
365 <p>If the <code>uid</code> attribute was used instead of the
366 <code>cn</code> attribute in the URL above, the above three lines
367 could be condensed to</p>
368 <example>Require ldap-user bjenson fuser jmanager</example>
371 <section id="reqgroup"><title>Require ldap-group</title>
373 <p>This directive specifies an LDAP group whose members are
374 allowed access. It takes the distinguished name of the LDAP
375 group. Note: Do not surround the group name with quotes.
376 For example, assume that the following entry existed in
377 the LDAP directory:</p>
379 dn: cn=Administrators, o=Airius<br />
380 objectClass: groupOfUniqueNames<br />
381 uniqueMember: cn=Barbara Jenson, o=Airius<br />
382 uniqueMember: cn=Fred User, o=Airius<br />
385 <p>The following directive would grant access to both Fred and
387 <example>Require ldap-group cn=Administrators, o=Airius</example>
389 <p>Members can also be found within sub-groups of a specified LDAP group
390 if <directive module="mod_authnz_ldap">AuthLDAPMaxSubGroupDepth</directive>
391 is set to a value greater than 0. For example, assume the following entries
392 exist in the LDAP directory:</p>
394 dn: cn=Employees, o=Airius<br />
395 objectClass: groupOfUniqueNames<br />
396 uniqueMember: cn=Managers, o=Airius<br />
397 uniqueMember: cn=Administrators, o=Airius<br />
398 uniqueMember: cn=Users, o=Airius<br />
400 dn: cn=Managers, o=Airius<br />
401 objectClass: groupOfUniqueNames<br />
402 uniqueMember: cn=Bob Ellis, o=Airius<br />
403 uniqueMember: cn=Tom Jackson, o=Airius<br />
405 dn: cn=Administrators, o=Airius<br />
406 objectClass: groupOfUniqueNames<br />
407 uniqueMember: cn=Barbara Jenson, o=Airius<br />
408 uniqueMember: cn=Fred User, o=Airius<br />
410 dn: cn=Users, o=Airius<br />
411 objectClass: groupOfUniqueNames<br />
412 uniqueMember: cn=Allan Jefferson, o=Airius<br />
413 uniqueMember: cn=Paul Tilley, o=Airius<br />
414 uniqueMember: cn=Temporary Employees, o=Airius<br />
416 dn: cn=Temporary Employees, o=Airius<br />
417 objectClass: groupOfUniqueNames<br />
418 uniqueMember: cn=Jim Swenson, o=Airius<br />
419 uniqueMember: cn=Elliot Rhodes, o=Airius<br />
422 <p>The following directives would allow access for Bob Ellis, Tom Jackson,
423 Barbara Jensen, Fred User, Allan Jefferson, and Paul Tilley but would not
424 allow access for Jim Swenson, or Elliot Rhodes (since they are at a
425 sub-group depth of 2):</p>
427 Require ldap-group cn=Employees, o-Airius<br />
428 AuthLDAPSubGroupDepth 1<br />
431 <p>Behavior of this directive is modified by the <directive
432 module="mod_authnz_ldap">AuthLDAPGroupAttribute</directive>, <directive
433 module="mod_authnz_ldap">AuthLDAPGroupAttributeIsDN</directive>, <directive
434 module="mod_authnz_ldap">AuthLDAPMaxSubGroupDepth</directive>, <directive
435 module="mod_authnz_ldap">AuthLDAPSubGroupAttribute</directive>, and <directive
436 module="mod_authnz_ldap">AuthLDAPSubGroupClass</directive>
440 <section id="reqdn"><title>Require ldap-dn</title>
442 <p>The <code>Require ldap-dn</code> directive allows the administrator
443 to grant access based on distinguished names. It specifies a DN
444 that must match for access to be granted. If the distinguished
445 name that was retrieved from the directory server matches the
446 distinguished name in the <code>Require ldap-dn</code>, then
447 authorization is granted. Note: do not surround the distinguished
448 name with quotes.</p>
450 <p>The following directive would grant access to a specific
452 <example>Require ldap-dn cn=Barbara Jenson, o=Airius</example>
454 <p>Behavior of this directive is modified by the <directive
455 module="mod_authnz_ldap">AuthLDAPCompareDNOnServer</directive>
459 <section id="reqattribute"><title>Require ldap-attribute</title>
461 <p>The <code>Require ldap-attribute</code> directive allows the
462 administrator to grant access based on attributes of the authenticated
463 user in the LDAP directory. If the attribute in the directory
464 matches the value given in the configuration, access is granted.</p>
466 <p>The following directive would grant access to anyone with
467 the attribute employeeType = active</p>
469 <example>Require ldap-attribute employeeType=active</example>
471 <p>Multiple attribute/value pairs can be specified on the same line
472 separated by spaces or they can be specified in multiple
473 <code>Require ldap-attribute</code> directives. The effect of listing
474 multiple attribute/values pairs is an OR operation. Access will be
475 granted if any of the listed attribute values match the value of the
476 corresponding attribute in the user object. If the value of the
477 attribute contains a space, only the value must be within double quotes.</p>
479 <p>The following directive would grant access to anyone with
480 the city attribute equal to "San Jose" or status equal to "Active"</p>
482 <example>Require ldap-attribute city="San Jose" status=active</example>
486 <section id="reqfilter"><title>Require ldap-filter</title>
488 <p>The <code>Require ldap-filter</code> directive allows the
489 administrator to grant access based on a complex LDAP search filter.
490 If the dn returned by the filter search matches the authenticated user
491 dn, access is granted.</p>
493 <p>The following directive would grant access to anyone having a cell phone
494 and is in the marketing department</p>
496 <example>Require ldap-filter &(cell=*)(department=marketing)</example>
498 <p>The difference between the <code>Require ldap-filter</code> directive and the
499 <code>Require ldap-attribute</code> directive is that <code>ldap-filter</code>
500 performs a search operation on the LDAP directory using the specified search
501 filter rather than a simple attribute comparison. If a simple attribute
502 comparison is all that is required, the comparison operation performed by
503 <code>ldap-attribute</code> will be faster than the search operation
504 used by <code>ldap-filter</code> especially within a large directory.</p>
510 <section id="examples"><title>Examples</title>
514 Grant access to anyone who exists in the LDAP directory,
515 using their UID for searches.
517 AuthLDAPURL "ldap://ldap1.airius.com:389/ou=People, o=Airius?uid?sub?(objectClass=*)"<br />
523 The next example is the same as above; but with the fields
524 that have useful defaults omitted. Also, note the use of a
525 redundant LDAP server.
526 <example>AuthLDAPURL "ldap://ldap1.airius.com ldap2.airius.com/ou=People, o=Airius"<br />
532 The next example is similar to the previous one, but it
533 uses the common name instead of the UID. Note that this
534 could be problematical if multiple people in the directory
535 share the same <code>cn</code>, because a search on <code>cn</code>
536 <strong>must</strong> return exactly one entry. That's why
537 this approach is not recommended: it's a better idea to
538 choose an attribute that is guaranteed unique in your
539 directory, such as <code>uid</code>.
541 AuthLDAPURL "ldap://ldap.airius.com/ou=People, o=Airius?cn"<br />
547 Grant access to anybody in the Administrators group. The
548 users must authenticate using their UID.
550 AuthLDAPURL ldap://ldap.airius.com/o=Airius?uid<br />
551 Require ldap-group cn=Administrators, o=Airius
556 The next example assumes that everyone at Airius who
557 carries an alphanumeric pager will have an LDAP attribute
558 of <code>qpagePagerID</code>. The example will grant access
559 only to people (authenticated via their UID) who have
562 AuthLDAPURL ldap://ldap.airius.com/o=Airius?uid??(qpagePagerID=*)<br />
568 <p>The next example demonstrates the power of using filters
569 to accomplish complicated administrative requirements.
570 Without filters, it would have been necessary to create a
571 new LDAP group and ensure that the group's members remain
572 synchronized with the pager users. This becomes trivial
573 with filters. The goal is to grant access to anyone who has
574 a pager, plus grant access to Joe Manager, who doesn't
575 have a pager, but does need to access the same
578 AuthLDAPURL ldap://ldap.airius.com/o=Airius?uid??(|(qpagePagerID=*)(uid=jmanager))<br />
582 <p>This last may look confusing at first, so it helps to
583 evaluate what the search filter will look like based on who
584 connects, as shown below. If
585 Fred User connects as <code>fuser</code>, the filter would look
588 <example>(&(|(qpagePagerID=*)(uid=jmanager))(uid=fuser))</example>
590 <p>The above search will only succeed if <em>fuser</em> has a
591 pager. When Joe Manager connects as <em>jmanager</em>, the
592 filter looks like</p>
594 <example>(&(|(qpagePagerID=*)(uid=jmanager))(uid=jmanager))</example>
596 <p>The above search will succeed whether <em>jmanager</em>
597 has a pager or not.</p>
602 <section id="usingtls"><title>Using TLS</title>
604 <p>To use TLS, see the <module>mod_ldap</module> directives <directive
605 module="mod_ldap">LDAPTrustedClientCert</directive>, <directive
606 module="mod_ldap">LDAPTrustedGlobalCert</directive> and <directive
607 module="mod_ldap">LDAPTrustedMode</directive>.</p>
609 <p>An optional second parameter can be added to the
610 <directive module="mod_authnz_ldap">AuthLDAPURL</directive> to override
611 the default connection type set by <directive module="mod_ldap">LDAPTrustedMode</directive>.
612 This will allow the connection established by an <em>ldap://</em> Url
613 to be upgraded to a secure connection on the same port.</p>
616 <section id="usingssl"><title>Using SSL</title>
618 <p>To use SSL, see the <module>mod_ldap</module> directives <directive
619 module="mod_ldap">LDAPTrustedClientCert</directive>, <directive
620 module="mod_ldap">LDAPTrustedGlobalCert</directive> and <directive
621 module="mod_ldap">LDAPTrustedMode</directive>.</p>
623 <p>To specify a secure LDAP server, use <em>ldaps://</em> in the
624 <directive module="mod_authnz_ldap">AuthLDAPURL</directive>
625 directive, instead of <em>ldap://</em>.</p>
628 <section id="exposed"><title>Exposing Login Information</title>
630 <p>When this module performs authentication, LDAP attributes specified
631 in the <directive module="mod_authnz_ldap">AuthLDAPUrl</directive>
632 directive are placed in environment variables with the prefix "AUTHENTICATE_".</p>
634 <p>If the attribute field contains the username, common name
635 and telephone number of a user, a CGI program will have access to
636 this information without the need to make a second independent LDAP
637 query to gather this additional information.</p>
639 <p>This has the potential to dramatically simplify the coding and
640 configuration required in some web applications.</p>
644 <section id="activedirectory"><title>Using Active Directory</title>
646 <p>An Active Directory installation may support multiple domains at the
647 same time. To distinguish users between domains, an identifier called
648 a User Principle Name (UPN) can be added to a user's entry in the
649 directory. This UPN usually takes the form of the user's account
650 name, followed by the domain components of the particular domain,
651 for example <em>somebody@nz.example.com</em>.</p>
653 <p>You may wish to configure the <module>mod_authnz_ldap</module>
654 module to authenticate users present in any of the domains making up
655 the Active Directory forest. In this way both
656 <em>somebody@nz.example.com</em> and <em>someone@au.example.com</em>
657 can be authenticated using the same query at the same time.</p>
659 <p>To make this practical, Active Directory supports the concept of
660 a Global Catalog. This Global Catalog is a read only copy of selected
661 attributes of all the Active Directory servers within the Active
662 Directory forest. Querying the Global Catalog allows all the domains
663 to be queried in a single query, without the query spanning servers
664 over potentially slow links.</p>
666 <p>If enabled, the Global Catalog is an independent directory server
667 that runs on port 3268 (3269 for SSL). To search for a user, do a
668 subtree search for the attribute <em>userPrincipalName</em>, with
669 an empty search root, like so:</p>
672 AuthLDAPBindDN apache@example.com<br />
673 AuthLDAPBindPassword password<br />
674 AuthLDAPURL ldap://10.0.0.1:3268/?userPrincipalName?sub
677 <p>Users will need to enter their User Principal Name as a login, in
678 the form <em>somebody@nz.example.com</em>.</p>
682 <section id="frontpage"><title>Using Microsoft
683 FrontPage with mod_authnz_ldap</title>
685 <p>Normally, FrontPage uses FrontPage-web-specific user/group
686 files (i.e., the <module>mod_authn_file</module> and
687 <module>mod_authz_groupfile</module> modules) to handle all
688 authentication. Unfortunately, it is not possible to just
689 change to LDAP authentication by adding the proper directives,
690 because it will break the <em>Permissions</em> forms in
691 the FrontPage client, which attempt to modify the standard
692 text-based authorization files.</p>
694 <p>Once a FrontPage web has been created, adding LDAP
695 authentication to it is a matter of adding the following
696 directives to <em>every</em> <code>.htaccess</code> file
697 that gets created in the web</p>
699 AuthLDAPURL "the url"
700 AuthGroupFile <em>mygroupfile</em>
701 Require group <em>mygroupfile</em>
704 <section id="howitworks"><title>How It Works</title>
706 <p>FrontPage restricts access to a web by adding the <code>Require
707 valid-user</code> directive to the <code>.htaccess</code>
708 files. The <code>Require valid-user</code> directive will succeed for
709 any user who is valid <em>as far as LDAP is
710 concerned</em>. This means that anybody who has an entry in
711 the LDAP directory is considered a valid user, whereas FrontPage
712 considers only those people in the local user file to be
713 valid. By substituting the ldap-group with group file authorization,
714 Apache is allowed to consult the local user file (which is managed by
715 FrontPage) - instead of LDAP - when handling authorizing the user.</p>
717 <p>Once directives have been added as specified above,
718 FrontPage users will be able to perform all management
719 operations from the FrontPage client.</p>
722 <section id="fpcaveats"><title>Caveats</title>
725 <li>When choosing the LDAP URL, the attribute to use for
726 authentication should be something that will also be valid
727 for putting into a <module>mod_authn_file</module> user file.
728 The user ID is ideal for this.</li>
730 <li>When adding users via FrontPage, FrontPage administrators
731 should choose usernames that already exist in the LDAP
732 directory (for obvious reasons). Also, the password that the
733 administrator enters into the form is ignored, since Apache
734 will actually be authenticating against the password in the
735 LDAP database, and not against the password in the local user
736 file. This could cause confusion for web administrators.</li>
738 <!-- XXX is that true? was mod_auth before the aaa change -->
739 <li>Apache must be compiled with <module>mod_auth_basic</module>,
740 <module>mod_authn_file</module> and
741 <module>mod_authz_groupfile</module> in order to
742 use FrontPage support. This is because Apache will still use
743 the <module>mod_authz_groupfile</module> group file for determine
744 the extent of a user's access to the FrontPage web.</li>
746 <li>The directives must be put in the <code>.htaccess</code>
747 files. Attempting to put them inside <directive module="core"
748 type="section">Location</directive> or <directive module="core"
749 type="section">Directory</directive> directives won't work. This
750 is because <module>mod_authnz_ldap</module> has to be able to grab
751 the <directive module="mod_authn_file">AuthGroupFile</directive>
752 directive that is found in FrontPage <code>.htaccess</code>
753 files so that it knows where to look for the valid user list. If
754 the <module>mod_authnz_ldap</module> directives aren't in the same
755 <code>.htaccess</code> file as the FrontPage directives, then
756 the hack won't work, because <module>mod_authnz_ldap</module> will
757 never get a chance to process the <code>.htaccess</code> file,
758 and won't be able to find the FrontPage-managed user file.</li>
764 <name>AuthLDAPBindDN</name>
765 <description>Optional DN to use in binding to the LDAP server</description>
766 <syntax>AuthLDAPBindDN <em>distinguished-name</em></syntax>
767 <contextlist><context>directory</context><context>.htaccess</context>
769 <override>AuthConfig</override>
772 <p>An optional DN used to bind to the server when searching for
773 entries. If not provided, <module>mod_authnz_ldap</module> will use
774 an anonymous bind.</p>
779 <name>AuthLDAPBindPassword</name>
780 <description>Password used in conjuction with the bind DN</description>
781 <syntax>AuthLDAPBindPassword <em>password</em></syntax>
782 <contextlist><context>directory</context><context>.htaccess</context>
784 <override>AuthConfig</override>
787 <p>A bind password to use in conjunction with the bind DN. Note
788 that the bind password is probably sensitive data, and should be
789 properly protected. You should only use the <directive
790 module="mod_authnz_ldap">AuthLDAPBindDN</directive> and <directive
791 module="mod_authnz_ldap">AuthLDAPBindPassword</directive> if you
792 absolutely need them to search the directory.</p>
797 <name>AuthLDAPCharsetConfig</name>
798 <description>Language to charset conversion configuration file</description>
799 <syntax>AuthLDAPCharsetConfig <em>file-path</em></syntax>
800 <contextlist><context>server config</context>
804 <p>The <directive>AuthLDAPCharsetConfig</directive> directive sets the location
805 of the language to charset conversion configuration file. <var>File-path</var> is relative
806 to the <directive module="core">ServerRoot</directive>. This file specifies
807 the list of language extensions to character sets.
808 Most administrators use the provided <code>charset.conv</code>
809 file, which associates common language extensions to character sets.</p>
811 <p>The file contains lines in the following format:</p>
814 <var>Language-Extension</var> <var>charset</var> [<var>Language-String</var>] ...
817 <p>The case of the extension does not matter. Blank lines, and lines
818 beginning with a hash character (<code>#</code>) are ignored.</p>
823 <name>AuthLDAPCompareDNOnServer</name>
824 <description>Use the LDAP server to compare the DNs</description>
825 <syntax>AuthLDAPCompareDNOnServer on|off</syntax>
826 <default>AuthLDAPCompareDNOnServer on</default>
827 <contextlist><context>directory</context><context>.htaccess</context>
829 <override>AuthConfig</override>
832 <p>When set, <module>mod_authnz_ldap</module> will use the LDAP
833 server to compare the DNs. This is the only foolproof way to
834 compare DNs. <module>mod_authnz_ldap</module> will search the
835 directory for the DN specified with the <a
836 href="#reqdn"><code>Require dn</code></a> directive, then,
837 retrieve the DN and compare it with the DN retrieved from the user
838 entry. If this directive is not set,
839 <module>mod_authnz_ldap</module> simply does a string comparison. It
840 is possible to get false negatives with this approach, but it is
841 much faster. Note the <module>mod_ldap</module> cache can speed up
842 DN comparison in most situations.</p>
847 <name>AuthLDAPDereferenceAliases</name>
848 <description>When will the module de-reference aliases</description>
849 <syntax>AuthLDAPDereferenceAliases never|searching|finding|always</syntax>
850 <default>AuthLDAPDereferenceAliases always</default>
851 <contextlist><context>directory</context><context>.htaccess</context>
853 <override>AuthConfig</override>
856 <p>This directive specifies when <module>mod_authnz_ldap</module> will
857 de-reference aliases during LDAP operations. The default is
858 <code>always</code>.</p>
863 <name>AuthLDAPGroupAttribute</name>
864 <description>LDAP attributes used to identify the user members of
865 groups.</description>
866 <syntax>AuthLDAPGroupAttribute <em>attribute</em></syntax>
867 <contextlist><context>directory</context><context>.htaccess</context>
869 <override>AuthConfig</override>
872 <p>This directive specifies which LDAP attributes are used to
873 check for user members within groups. Multiple attributes can be used
874 by specifying this directive multiple times. If not specified,
875 then <module>mod_authnz_ldap</module> uses the <code>member</code> and
876 <code>uniquemember</code> attributes.</p>
881 <name>AuthLDAPGroupAttributeIsDN</name>
882 <description>Use the DN of the client username when checking for
883 group membership</description>
884 <syntax>AuthLDAPGroupAttributeIsDN on|off</syntax>
885 <default>AuthLDAPGroupAttributeIsDN on</default>
886 <contextlist><context>directory</context><context>.htaccess</context>
888 <override>AuthConfig</override>
891 <p>When set <code>on</code>, this directive says to use the
892 distinguished name of the client username when checking for group
893 membership. Otherwise, the username will be used. For example,
894 assume that the client sent the username <code>bjenson</code>,
895 which corresponds to the LDAP DN <code>cn=Babs Jenson,
896 o=Airius</code>. If this directive is set,
897 <module>mod_authnz_ldap</module> will check if the group has
898 <code>cn=Babs Jenson, o=Airius</code> as a member. If this
899 directive is not set, then <module>mod_authnz_ldap</module> will
900 check if the group has <code>bjenson</code> as a member.</p>
905 <name>AuthLDAPMaxSubGroupDepth</name>
906 <description>Specifies the maximum sub-group nesting depth that will be
907 evaluated before the user search is discontinued.</description>
908 <syntax>AuthLDAPMaxSubGroupDepth <var>Number</var></syntax>
909 <default>AuthLDAPMaxSubGroupDepth 10</default>
910 <contextlist><context>directory</context><context>.htaccess</context>
912 <override>AuthConfig</override>
915 <p>When this directive is set to a non-zero value <code>X</code>
916 combined with use of the <code>Require ldap-group someGroupDN</code>
917 directive, the provided user credentials will be searched for
918 as a member of the <code>someGroupDN</code> directory object or of
919 any group member of the current group up to the maximum nesting
920 level <code>X</code> specified by this directive.</p>
921 <p>See the <a href="#reqgroup"><code>Require ldap-group</code></a>
922 section for a more detailed example.</p>
927 <name>AuthLDAPRemoteUserAttribute</name>
928 <description>Use the value of the attribute returned during the user
929 query to set the REMOTE_USER environment variable</description>
930 <syntax>AuthLDAPRemoteUserAttribute uid</syntax>
931 <default>none</default>
932 <contextlist><context>directory</context><context>.htaccess</context>
934 <override>AuthConfig</override>
937 <p>If this directive is set, the value of the
938 <code>REMOTE_USER</code> environment variable will be set to the
939 value of the attribute specified. Make sure that this attribute is
940 included in the list of attributes in the AuthLDAPUrl definition,
941 otherwise this directive will have no effect. This directive, if
942 present, takes precedence over AuthLDAPRemoteUserIsDN. This
943 directive is useful should you want people to log into a website
944 using an email address, but a backend application expects the
945 username as a userid.</p>
950 <name>AuthLDAPRemoteUserIsDN</name>
951 <description>Use the DN of the client username to set the REMOTE_USER
952 environment variable</description>
953 <syntax>AuthLDAPRemoteUserIsDN on|off</syntax>
954 <default>AuthLDAPRemoteUserIsDN off</default>
955 <contextlist><context>directory</context><context>.htaccess</context>
957 <override>AuthConfig</override>
960 <p>If this directive is set to on, the value of the
961 <code>REMOTE_USER</code> environment variable will be set to the full
962 distinguished name of the authenticated user, rather than just
963 the username that was passed by the client. It is turned off by
969 <name>AuthLDAPSubGroupAttribute</name>
970 <description>Specifies the attribute labels, one value per
971 directive line, used to distinguish the members of the current group that
972 are groups.</description>
973 <syntax>AuthLDAPSubGroupAttribute <em>attribute</em></syntax>
974 <contextlist><context>directory</context><context>.htaccess</context>
976 <override>AuthConfig</override>
979 <p>An LDAP group object may contain members that are users and
980 members that are groups (called nested or sub groups). The
981 <code>AuthLDAPSubGroupAttribute</code> directive identifies the
982 labels of group members and the <code>AuthLDAPGroupAttribute</code>
983 directive identifies the labels of the user members. Multiple
984 attributes can be used by specifying this directive multiple times.
985 If not specified, then <module>mod_authnz_ldap</module> uses the
986 <code>member</code> and <code>uniqueMember</code> attributes.</p>
991 <name>AuthLDAPSubGroupClass</name>
992 <description>Specifies which LDAP objectClass values identify directory
993 objects that are groups during sub-group processing.</description>
994 <syntax>AuthLDAPSubGroupClass <em>LdapObjectClass</em></syntax>
995 <contextlist><context>directory</context><context>.htaccess</context>
997 <override>AuthConfig</override>
1000 <p>An LDAP group object may contain members that are users and
1001 members that are groups (called nested or sub groups). The
1002 <code>AuthLDAPSubGroupAttribute</code> directive identifies the
1003 labels of members that may be sub-groups of the current group
1004 (as opposed to user members). The <code>AuthLDAPSubGroupClass</code>
1005 directive specifies the LDAP objectClass values used in verifying that
1006 these potential sub-groups are in fact group objects. Verified sub-groups
1007 can then be searched for more user or sub-group members. Multiple
1008 attributes can be used by specifying this directive multiple times.
1009 If not specified, then <module>mod_authnz_ldap</module> uses the
1010 <code>groupOfNames</code> and <code>groupOfUniqueNames</code> values.</p>
1012 </directivesynopsis>
1015 <name>AuthLDAPUrl</name>
1016 <description>URL specifying the LDAP search parameters</description>
1017 <syntax>AuthLDAPUrl <em>url [NONE|SSL|TLS|STARTTLS]</em></syntax>
1018 <contextlist><context>directory</context><context>.htaccess</context>
1020 <override>AuthConfig</override>
1023 <p>An RFC 2255 URL which specifies the LDAP search parameters
1024 to use. The syntax of the URL is</p>
1025 <example>ldap://host:port/basedn?attribute?scope?filter</example>
1026 <p>If you want to specify more than one LDAP URL that Apache should try in turn, the syntax is:</p>
1027 <example>AuthLDAPUrl "ldap://ldap1.example.com ldap2.example.com/dc=..."</example>
1028 <p><em><strong>Caveat: </strong>If you specify multiple servers, you need to enclose the entire URL string in quotes;
1029 otherwise you will get an error: "AuthLDAPURL takes one argument, URL to define LDAP connection.." </em>
1030 You can of course use search parameters on each of these.</p>
1035 <dd>For regular ldap, use the
1036 string <code>ldap</code>. For secure LDAP, use <code>ldaps</code>
1037 instead. Secure LDAP is only available if Apache was linked
1038 to an LDAP library with SSL support.</dd>
1043 <p>The name/port of the ldap server (defaults to
1044 <code>localhost:389</code> for <code>ldap</code>, and
1045 <code>localhost:636</code> for <code>ldaps</code>). To
1046 specify multiple, redundant LDAP servers, just list all
1047 servers, separated by spaces. <module>mod_authnz_ldap</module>
1048 will try connecting to each server in turn, until it makes a
1049 successful connection. If multiple ldap servers are specified,
1050 then entire LDAP URL must be encapsulated in double quotes.</p>
1052 <p>Once a connection has been made to a server, that
1053 connection remains active for the life of the
1054 <program>httpd</program> process, or until the LDAP server goes
1057 <p>If the LDAP server goes down and breaks an existing
1058 connection, <module>mod_authnz_ldap</module> will attempt to
1059 re-connect, starting with the primary server, and trying
1060 each redundant server in turn. Note that this is different
1061 than a true round-robin search.</p>
1066 <dd>The DN of the branch of the
1067 directory where all searches should start from. At the very
1068 least, this must be the top of your directory tree, but
1069 could also specify a subtree in the directory.</dd>
1073 <dd>The attribute to search for.
1074 Although RFC 2255 allows a comma-separated list of
1075 attributes, only the first attribute will be used, no
1076 matter how many are provided. If no attributes are
1077 provided, the default is to use <code>uid</code>. It's a good
1078 idea to choose an attribute that will be unique across all
1079 entries in the subtree you will be using. All attributes
1080 listed will be put into the environment with an AUTHENTICATE_ prefix
1081 for use by other modules.</dd>
1085 <dd>The scope of the search. Can be either <code>one</code> or
1086 <code>sub</code>. Note that a scope of <code>base</code> is
1087 also supported by RFC 2255, but is not supported by this
1088 module. If the scope is not provided, or if <code>base</code> scope
1089 is specified, the default is to use a scope of
1090 <code>sub</code>.</dd>
1094 <dd>A valid LDAP search filter. If
1095 not provided, defaults to <code>(objectClass=*)</code>, which
1096 will search for all objects in the tree. Filters are
1097 limited to approximately 8000 characters (the definition of
1098 <code>MAX_STRING_LEN</code> in the Apache source code). This
1099 should be more than sufficient for any application.</dd>
1102 <p>When doing searches, the attribute, filter and username passed
1103 by the HTTP client are combined to create a search filter that
1105 <code>(&(<em>filter</em>)(<em>attribute</em>=<em>username</em>))</code>.</p>
1107 <p>For example, consider an URL of
1108 <code>ldap://ldap.airius.com/o=Airius?cn?sub?(posixid=*)</code>. When
1109 a client attempts to connect using a username of <code>Babs
1110 Jenson</code>, the resulting search filter will be
1111 <code>(&(posixid=*)(cn=Babs Jenson))</code>.</p>
1113 <p>An optional parameter can be added to allow the LDAP Url to override
1114 the connection type. This parameter can be one of the following:</p>
1118 <dd>Establish an unsecure connection on the default LDAP port. This
1119 is the same as <code>ldap://</code> on port 389.</dd>
1121 <dd>Establish a secure connection on the default secure LDAP port.
1122 This is the same as <code>ldaps://</code></dd>
1123 <dt>TLS | STARTTLS</dt>
1124 <dd>Establish an upgraded secure connection on the default LDAP port.
1125 This connection will be initiated on port 389 by default and then
1126 upgraded to a secure connection on the same port.</dd>
1129 <p>See above for examples of <directive
1130 module="mod_authnz_ldap">AuthLDAPURL</directive> URLs.</p>
1132 </directivesynopsis>