1 /* $Cambridge: exim/src/src/lookups/ldap.c,v 1.15 2009/11/16 19:50:38 nm4 Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2009 */
8 /* See the file NOTICE for conditions of use and distribution. */
10 /* Many thanks to Stuart Lynne for contributing the original code for this
11 driver. Further contibutions from Michael Haardt, Brian Candler, Barry
12 Pederson, Peter Savitch and Christian Kellner. Particular thanks to Brian for
13 researching how to handle the different kinds of error. */
17 #include "lf_functions.h"
20 /* Include LDAP headers. The code below uses some "old" LDAP interfaces that
21 are deprecated in OpenLDAP. I don't know their status in other LDAP
22 implementations. LDAP_DEPRECATED causes their prototypes to be defined in
25 #define LDAP_DEPRECATED 1
31 /* Annoyingly, the different LDAP libraries handle errors in different ways,
32 and some other things too. There doesn't seem to be an automatic way of
33 distinguishing between them. Local/Makefile should contain a setting of
34 LDAP_LIB_TYPE, which in turn causes appropriate macros to be defined for the
35 different kinds. Those that matter are:
38 LDAP_LIB_SOLARIS with synonym LDAP_LIB_SOLARIS7
41 These others may be defined, but are in fact the default, so are not tested:
47 #if defined(LDAP_LIB_SOLARIS7) && ! defined(LDAP_LIB_SOLARIS)
48 #define LDAP_LIB_SOLARIS
52 /* Just in case LDAP_NO_LIMIT is not defined by some of these libraries. */
55 #define LDAP_NO_LIMIT 0
59 /* Just in case LDAP_DEREF_NEVER is not defined */
61 #ifndef LDAP_DEREF_NEVER
62 #define LDAP_DEREF_NEVER 0
66 /* Four types of LDAP search are implemented */
68 #define SEARCH_LDAP_MULTIPLE 0 /* Get attributes from multiple entries */
69 #define SEARCH_LDAP_SINGLE 1 /* Get attributes from one entry only */
70 #define SEARCH_LDAP_DN 2 /* Get just the DN from one entry */
71 #define SEARCH_LDAP_AUTH 3 /* Just checking for authentication */
73 /* In all 4 cases, the DN is left in $ldap_dn (which post-dates the
74 SEARCH_LDAP_DN lookup). */
77 /* Structure and anchor for caching connections. */
79 typedef struct ldap_connection {
80 struct ldap_connection *next;
89 static LDAP_CONNECTION *ldap_connections = NULL;
93 /*************************************************
94 * Internal search function *
95 *************************************************/
97 /* This is the function that actually does the work. It is called (indirectly
98 via control_ldap_search) from eldap_find(), eldapauth_find(), eldapdn_find(),
99 and eldapm_find(), with a difference in the "search_type" argument.
101 The case of eldapauth_find() is special in that all it does is do
102 authentication, returning OK or FAIL as appropriate. This isn't used as a
103 lookup. Instead, it is called from expand.c as an expansion condition test.
105 The DN from a successful lookup is placed in $ldap_dn. This feature postdates
106 the provision of the SEARCH_LDAP_DN facility for returning just the DN as the
110 ldap_url the URL to be looked up
111 server server host name, when URL contains none
112 s_port server port, used when URL contains no name
113 search_type SEARCH_LDAP_MULTIPLE allows values from multiple entries
114 SEARCH_LDAP_SINGLE allows values from one entry only
115 SEARCH_LDAP_DN gets the DN from one entry
116 res set to point at the result (not used for ldapauth)
117 errmsg set to point a message if result is not OK
118 defer_break set TRUE if no more servers to be tried after a DEFER
119 user user name for authentication, or NULL
120 password password for authentication, or NULL
121 sizelimit max number of entries returned, or 0 for no limit
122 timelimit max time to wait, or 0 for no limit
123 tcplimit max time for network activity, e.g. connect, or 0 for OS default
124 deference the dereference option, which is one of
125 LDAP_DEREF_{NEVER,SEARCHING,FINDING,ALWAYS}
126 referrals the referral option, which is LDAP_OPT_ON or LDAP_OPT_OFF
128 Returns: OK or FAIL or DEFER
129 FAIL is given only if a lookup was performed successfully, but
134 perform_ldap_search(uschar *ldap_url, uschar *server, int s_port, int search_type,
135 uschar **res, uschar **errmsg, BOOL *defer_break, uschar *user, uschar *password,
136 int sizelimit, int timelimit, int tcplimit, int dereference, void *referrals)
138 LDAPURLDesc *ludp = NULL;
139 LDAPMessage *result = NULL;
141 LDAP_CONNECTION *lcp;
143 struct timeval timeout;
144 struct timeval *timeoutptr = NULL;
155 uschar *error1 = NULL; /* string representation of errcode (static) */
156 uschar *error2 = NULL; /* error message from the server */
157 uschar *matched = NULL; /* partially matched DN */
160 int error_yield = DEFER;
162 int rc, ldap_rc, ldap_parse_rc;
167 BOOL attribute_found = FALSE;
171 debug_printf("perform_ldap_search: ldap%s URL = \"%s\" server=%s port=%d "
172 "sizelimit=%d timelimit=%d tcplimit=%d\n",
173 (search_type == SEARCH_LDAP_MULTIPLE)? "m" :
174 (search_type == SEARCH_LDAP_DN)? "dn" :
175 (search_type == SEARCH_LDAP_AUTH)? "auth" : "",
176 ldap_url, server, s_port, sizelimit, timelimit, tcplimit);
178 /* Check if LDAP thinks the URL is a valid LDAP URL. We assume that if the LDAP
179 library that is in use doesn't recognize, say, "ldapi", it will barf here. */
181 if (!ldap_is_ldap_url(CS ldap_url))
183 *errmsg = string_sprintf("ldap_is_ldap_url: not an LDAP url \"%s\"\n",
185 goto RETURN_ERROR_BREAK;
190 if ((rc = ldap_url_parse(CS ldap_url, &ludp)) != 0)
192 *errmsg = string_sprintf("ldap_url_parse: (error %d) parsing \"%s\"\n", rc,
194 goto RETURN_ERROR_BREAK;
197 /* If the host name is empty, take it from the separate argument, if one is
198 given. OpenLDAP 2.0.6 sets an unset hostname to "" rather than empty, but
199 expects NULL later in ldap_init() to mean "default", annoyingly. In OpenLDAP
200 2.0.11 this has changed (it uses NULL). */
202 if ((ludp->lud_host == NULL || ludp->lud_host[0] == 0) && server != NULL)
209 host = US ludp->lud_host;
210 if (host != NULL && host[0] == 0) host = NULL;
211 port = ludp->lud_port;
214 DEBUG(D_lookup) debug_printf("after ldap_url_parse: host=%s port=%d\n",
217 if (port == 0) port = LDAP_PORT; /* Default if none given */
218 sprintf(CS porttext, ":%d", port); /* For messages */
220 /* If the "host name" is actually a path, we are going to connect using a Unix
221 socket, regardless of whether "ldapi" was actually specified or not. This means
222 that a Unix socket can be declared in eldap_default_servers, and "traditional"
223 LDAP queries using just "ldap" can be used ("ldaps" is similarly overridden).
224 The path may start with "/" or it may already be escaped as "%2F" if it was
225 actually declared that way in eldap_default_servers. (I did it that way the
226 first time.) If the host name is not a path, the use of "ldapi" causes an
227 error, except in the default case. (But lud_scheme doesn't seem to exist in
232 if ((host[0] == '/' || Ustrncmp(host, "%2F", 3) == 0))
235 porttext[0] = 0; /* Remove port from messages */
238 #if defined LDAP_LIB_OPENLDAP2
239 else if (strncmp(ludp->lud_scheme, "ldapi", 5) == 0)
241 *errmsg = string_sprintf("ldapi requires an absolute path (\"%s\" given)",
248 /* Count the attributes; we need this later to tell us how to format results */
250 for (attrp = USS ludp->lud_attrs; attrp != NULL && *attrp != NULL; attrp++)
253 /* See if we can find a cached connection to this host. The port is not
254 relevant for ldapi. The host name pointer is set to NULL if no host was given
255 (implying the library default), rather than to the empty string. Note that in
256 this case, there is no difference between ldap and ldapi. */
258 for (lcp = ldap_connections; lcp != NULL; lcp = lcp->next)
260 if ((host == NULL) != (lcp->host == NULL) ||
261 (host != NULL && strcmpic(lcp->host, host) != 0))
263 if (ldapi || port == lcp->port) break;
266 /* Use this network timeout in any requests. */
270 timeout.tv_sec = tcplimit;
272 timeoutptr = &timeout;
275 /* If no cached connection found, we must open a connection to the server. If
276 the server name is actually an absolute path, we set ldapi=TRUE above. This
277 requests connection via a Unix socket. However, as far as I know, only OpenLDAP
278 supports the use of sockets, and the use of ldap_initialize(). */
285 /* --------------------------- OpenLDAP ------------------------ */
287 /* There seems to be a preference under OpenLDAP for ldap_initialize()
288 instead of ldap_init(), though I have as yet been unable to find
289 documentation that says this. (OpenLDAP documentation is sparse to
290 non-existent). So we handle OpenLDAP differently here. Also, support for
291 ldapi seems to be OpenLDAP-only at present. */
293 #ifdef LDAP_LIB_OPENLDAP2
295 /* We now need an empty string for the default host. Get some store in which
296 to build a URL for ldap_initialize(). In the ldapi case, it can't be bigger
297 than (9 + 3*Ustrlen(shost)), whereas in the other cases it can't be bigger
298 than the host name + "ldaps:///" plus : and a port number, say 20 + the
299 length of the host name. What we get should accommodate both, easily. */
301 uschar *shost = (host == NULL)? US"" : host;
302 uschar *init_url = store_get(20 + 3 * Ustrlen(shost));
305 /* Handle connection via Unix socket ("ldapi"). We build a basic LDAP URI to
306 contain the path name, with slashes escaped as %2F. */
311 init_ptr = init_url + 8;
312 Ustrcpy(init_url, "ldapi://");
313 while ((ch = *shost++) != 0)
317 Ustrncpy(init_ptr, "%2F", 3);
320 else *init_ptr++ = ch;
325 /* This is not an ldapi call. Just build a URI with the protocol type, host
330 init_ptr = Ustrchr(ldap_url, '/');
331 Ustrncpy(init_url, ldap_url, init_ptr - ldap_url);
332 init_ptr = init_url + (init_ptr - ldap_url);
333 sprintf(CS init_ptr, "//%s:%d/", shost, port);
336 /* Call ldap_initialize() and check the result */
338 DEBUG(D_lookup) debug_printf("ldap_initialize with URL %s\n", init_url);
339 rc = ldap_initialize(&ld, CS init_url);
340 if (rc != LDAP_SUCCESS)
342 *errmsg = string_sprintf("ldap_initialize: (error %d) URL \"%s\"\n",
346 store_reset(init_url); /* Might as well save memory when we can */
349 /* ------------------------- Not OpenLDAP ---------------------- */
351 /* For libraries other than OpenLDAP, use ldap_init(). */
353 #else /* LDAP_LIB_OPENLDAP2 */
354 ld = ldap_init(CS host, port);
355 #endif /* LDAP_LIB_OPENLDAP2 */
357 /* -------------------------------------------------------------- */
360 /* Handle failure to initialize */
364 *errmsg = string_sprintf("failed to initialize for LDAP server %s%s - %s",
365 host, porttext, strerror(errno));
369 /* Set the TCP connect time limit if available. This is something that is
370 in Netscape SDK v4.1; I don't know about other libraries. */
372 #ifdef LDAP_X_OPT_CONNECT_TIMEOUT
375 int timeout1000 = tcplimit*1000;
376 ldap_set_option(ld, LDAP_X_OPT_CONNECT_TIMEOUT, (void *)&timeout1000);
380 int notimeout = LDAP_X_IO_TIMEOUT_NO_TIMEOUT;
381 ldap_set_option(ld, LDAP_X_OPT_CONNECT_TIMEOUT, (void *)¬imeout);
385 /* Set the TCP connect timeout. This works with OpenLDAP 2.2.14. */
387 #ifdef LDAP_OPT_NETWORK_TIMEOUT
389 ldap_set_option(ld, LDAP_OPT_NETWORK_TIMEOUT, (void *)timeoutptr);
392 /* I could not get TLS to work until I set the version to 3. That version
393 seems to be the default nowadays. The RFC is dated 1997, so I would hope
394 that all the LDAP libraries support it. Therefore, if eldap_version hasn't
395 been set, go for v3 if we can. */
397 if (eldap_version < 0)
400 eldap_version = LDAP_VERSION3;
406 #ifdef LDAP_OPT_PROTOCOL_VERSION
407 ldap_set_option(ld, LDAP_OPT_PROTOCOL_VERSION, (void *)&eldap_version);
410 DEBUG(D_lookup) debug_printf("initialized for LDAP (v%d) server %s%s\n",
411 eldap_version, host, porttext);
413 /* If not using ldapi and TLS is available, set appropriate TLS options: hard
414 for "ldaps" and soft otherwise. */
416 #ifdef LDAP_OPT_X_TLS
420 if (strncmp(ludp->lud_scheme, "ldaps", 5) == 0)
422 tls_option = LDAP_OPT_X_TLS_HARD;
423 DEBUG(D_lookup) debug_printf("LDAP_OPT_X_TLS_HARD set\n");
427 tls_option = LDAP_OPT_X_TLS_TRY;
428 DEBUG(D_lookup) debug_printf("LDAP_OPT_X_TLS_TRY set\n");
430 ldap_set_option(ld, LDAP_OPT_X_TLS, (void *)&tls_option);
432 #endif /* LDAP_OPT_X_TLS */
434 #ifdef LDAP_OPT_X_TLS_CACERTFILE
435 if (eldap_ca_cert_file != NULL)
437 ldap_set_option(ld, LDAP_OPT_X_TLS_CACERTFILE, eldap_ca_cert_file);
440 #ifdef LDAP_OPT_X_TLS_CACERTDIR
441 if (eldap_ca_cert_dir != NULL)
443 ldap_set_option(ld, LDAP_OPT_X_TLS_CACERTDIR, eldap_ca_cert_dir);
446 #ifdef LDAP_OPT_X_TLS_CERTFILE
447 if (eldap_cert_file != NULL)
449 ldap_set_option(ld, LDAP_OPT_X_TLS_CERTFILE, eldap_cert_file);
452 #ifdef LDAP_OPT_X_TLS_KEYFILE
453 if (eldap_cert_key != NULL)
455 ldap_set_option(ld, LDAP_OPT_X_TLS_KEYFILE, eldap_cert_key);
458 #ifdef LDAP_OPT_X_TLS_CIPHER_SUITE
459 if (eldap_cipher_suite != NULL)
461 ldap_set_option(ld, LDAP_OPT_X_TLS_CIPHER_SUITE, eldap_cipher_suite);
464 #ifdef LDAP_OPT_X_TLS_REQUIRE_CERT
465 if (eldap_require_cert != NULL)
467 int cert_option = LDAP_OPT_X_TLS_NEVER;
468 if (Ustrcmp(eldap_require_cert, "hard") == 0)
470 cert_option = LDAP_OPT_X_TLS_HARD;
472 else if (Ustrcmp(eldap_require_cert, "demand") == 0)
474 cert_option = LDAP_OPT_X_TLS_DEMAND;
476 else if (Ustrcmp(eldap_require_cert, "allow") == 0)
478 cert_option = LDAP_OPT_X_TLS_ALLOW;
480 else if (Ustrcmp(eldap_require_cert, "try") == 0)
482 cert_option = LDAP_OPT_X_TLS_TRY;
484 ldap_set_option(ld, LDAP_OPT_X_TLS_REQUIRE_CERT, &cert_option);
488 /* Now add this connection to the chain of cached connections */
490 lcp = store_get(sizeof(LDAP_CONNECTION));
491 lcp->host = (host == NULL)? NULL : string_copy(host);
494 lcp->password = NULL;
497 lcp->next = ldap_connections;
498 ldap_connections = lcp;
501 /* Found cached connection */
506 debug_printf("re-using cached connection to LDAP server %s%s\n",
510 /* Bind with the user/password supplied, or an anonymous bind if these values
511 are NULL, unless a cached connection is already bound with the same values. */
514 (lcp->user == NULL && user != NULL) ||
515 (lcp->user != NULL && user == NULL) ||
516 (lcp->user != NULL && user != NULL && Ustrcmp(lcp->user, user) != 0) ||
517 (lcp->password == NULL && password != NULL) ||
518 (lcp->password != NULL && password == NULL) ||
519 (lcp->password != NULL && password != NULL &&
520 Ustrcmp(lcp->password, password) != 0))
522 DEBUG(D_lookup) debug_printf("%sbinding with user=%s password=%s\n",
523 (lcp->bound)? "re-" : "", user, password);
526 ldap_start_tls_s(lcp->ld, NULL, NULL);
528 if ((msgid = ldap_bind(lcp->ld, CS user, CS password, LDAP_AUTH_SIMPLE))
531 *errmsg = string_sprintf("failed to bind the LDAP connection to server "
532 "%s%s - ldap_bind() returned -1", host, porttext);
536 if ((rc = ldap_result( lcp->ld, msgid, 1, timeoutptr, &result )) <= 0)
538 *errmsg = string_sprintf("failed to bind the LDAP connection to server "
539 "%s%s - LDAP error: %s", host, porttext,
540 rc == -1 ? "result retrieval failed" : "timeout" );
545 rc = ldap_result2error( lcp->ld, result, 0 );
547 /* Invalid credentials when just checking credentials returns FAIL. This
548 stops any further servers being tried. */
550 if (search_type == SEARCH_LDAP_AUTH && rc == LDAP_INVALID_CREDENTIALS)
553 debug_printf("Invalid credentials: ldapauth returns FAIL\n");
555 goto RETURN_ERROR_NOMSG;
558 /* Otherwise we have a problem that doesn't stop further servers from being
561 if (rc != LDAP_SUCCESS)
563 *errmsg = string_sprintf("failed to bind the LDAP connection to server "
564 "%s%s - LDAP error %d: %s", host, porttext, rc, ldap_err2string(rc));
568 /* Successful bind */
571 lcp->user = (user == NULL)? NULL : string_copy(user);
572 lcp->password = (password == NULL)? NULL : string_copy(password);
574 ldap_msgfree(result);
578 /* If we are just checking credentials, return OK. */
580 if (search_type == SEARCH_LDAP_AUTH)
582 DEBUG(D_lookup) debug_printf("Bind succeeded: ldapauth returns OK\n");
586 /* Before doing the search, set the time and size limits (if given). Here again
587 the different implementations of LDAP have chosen to do things differently. */
589 #if defined(LDAP_OPT_SIZELIMIT)
590 ldap_set_option(lcp->ld, LDAP_OPT_SIZELIMIT, (void *)&sizelimit);
591 ldap_set_option(lcp->ld, LDAP_OPT_TIMELIMIT, (void *)&timelimit);
593 lcp->ld->ld_sizelimit = sizelimit;
594 lcp->ld->ld_timelimit = timelimit;
597 /* Similarly for dereferencing aliases. Don't know if this is possible on
598 an LDAP library without LDAP_OPT_DEREF. */
600 #if defined(LDAP_OPT_DEREF)
601 ldap_set_option(lcp->ld, LDAP_OPT_DEREF, (void *)&dereference);
604 /* Similarly for the referral setting; should the library follow referrals that
605 the LDAP server returns? The conditional is just in case someone uses a library
608 #if defined(LDAP_OPT_REFERRALS)
609 ldap_set_option(lcp->ld, LDAP_OPT_REFERRALS, referrals);
612 /* Start the search on the server. */
614 DEBUG(D_lookup) debug_printf("Start search\n");
616 msgid = ldap_search(lcp->ld, ludp->lud_dn, ludp->lud_scope, ludp->lud_filter,
621 #if defined LDAP_LIB_SOLARIS || defined LDAP_LIB_OPENLDAP2
623 ldap_get_option(lcp->ld, LDAP_OPT_ERROR_NUMBER, &err);
624 *errmsg = string_sprintf("ldap_search failed: %d, %s", err,
625 ldap_err2string(err));
628 *errmsg = string_sprintf("ldap_search failed");
634 /* Loop to pick up results as they come in, setting a timeout if one was
637 while ((rc = ldap_result(lcp->ld, msgid, 0, timeoutptr, &result)) ==
638 LDAP_RES_SEARCH_ENTRY)
642 DEBUG(D_lookup) debug_printf("ldap_result loop\n");
644 for(e = ldap_first_entry(lcp->ld, result);
646 e = ldap_next_entry(lcp->ld, e))
649 BOOL insert_space = FALSE;
651 DEBUG(D_lookup) debug_printf("LDAP entry loop\n");
653 rescount++; /* Count results */
655 /* Results for multiple entries values are separated by newlines. */
657 if (data != NULL) data = string_cat(data, &size, &ptr, US"\n", 1);
659 /* Get the DN from the last result. */
661 new_dn = US ldap_get_dn(lcp->ld, e);
666 #if defined LDAP_LIB_NETSCAPE || defined LDAP_LIB_OPENLDAP2
668 #else /* OPENLDAP 1, UMich, Solaris */
676 /* If the data we want is actually the DN rather than any attribute values,
677 (an "ldapdn" search) add it to the data string. If there are multiple
678 entries, the DNs will be concatenated, but we test for this case below, as
679 for SEARCH_LDAP_SINGLE, and give an error. */
681 if (search_type == SEARCH_LDAP_DN) /* Do not amalgamate these into one */
682 { /* condition, because of the else */
683 if (new_dn != NULL) /* below, that's for the first only */
685 data = string_cat(data, &size, &ptr, new_dn, Ustrlen(new_dn));
687 attribute_found = TRUE;
691 /* Otherwise, loop through the entry, grabbing attribute values. If there's
692 only one attribute being retrieved, no attribute name is given, and the
693 result is not quoted. Multiple values are separated by (comma, space).
694 If more than one attribute is being retrieved, the data is given as a
695 sequence of name=value pairs, with the value always in quotes. If there are
696 multiple values, they are given within the quotes, comma separated. */
698 else for (attr = US ldap_first_attribute(lcp->ld, e, &ber);
700 attr = US ldap_next_attribute(lcp->ld, e, ber))
704 /* Get array of values for this attribute. */
706 if ((firstval = values = USS ldap_get_values(lcp->ld, e, CS attr))
712 data = string_cat(data, &size, &ptr, US" ", 1);
715 data = string_cat(data, &size, &ptr, attr, Ustrlen(attr));
716 data = string_cat(data, &size, &ptr, US"=\"", 2);
719 while (*values != NULL)
721 uschar *value = *values;
722 int len = Ustrlen(value);
724 DEBUG(D_lookup) debug_printf("LDAP attr loop %s:%s\n", attr, value);
726 if (values != firstval)
727 data = string_cat(data, &size, &ptr, US", ", 2);
729 /* For multiple attributes, the data is in quotes. We must escape
730 internal quotes, backslashes, newlines. */
735 for (j = 0; j < len; j++)
737 if (value[j] == '\n')
738 data = string_cat(data, &size, &ptr, US"\\n", 2);
741 if (value[j] == '\"' || value[j] == '\\')
742 data = string_cat(data, &size, &ptr, US"\\", 1);
743 data = string_cat(data, &size, &ptr, value+j, 1);
748 /* For single attributes, copy the value verbatim */
750 else data = string_cat(data, &size, &ptr, value, len);
752 /* Move on to the next value */
755 attribute_found = TRUE;
758 /* Closing quote at the end of the data for a named attribute. */
761 data = string_cat(data, &size, &ptr, US"\"", 1);
763 /* Free the values */
765 ldap_value_free(CSS firstval);
769 #if defined LDAP_LIB_NETSCAPE || defined LDAP_LIB_OPENLDAP2
771 /* Netscape and OpenLDAP2 LDAP's attrs are dynamically allocated and need
772 to be freed. UMich LDAP stores them in static storage and does not require
777 } /* End "for" loop for extracting attributes from an entry */
778 } /* End "for" loop for extracting entries from a result */
780 /* Free the result */
782 ldap_msgfree(result);
784 } /* End "while" loop for multiple results */
786 /* Terminate the dynamic string that we have built and reclaim unused store */
791 store_reset(data + ptr + 1);
794 /* Copy the last dn into eldap_dn */
798 eldap_dn = string_copy(dn);
799 #if defined LDAP_LIB_NETSCAPE || defined LDAP_LIB_OPENLDAP2
801 #else /* OPENLDAP 1, UMich, Solaris */
806 DEBUG(D_lookup) debug_printf("search ended by ldap_result yielding %d\n",rc);
810 *errmsg = US"ldap_result timed out";
814 /* A return code of -1 seems to mean "ldap_result failed internally or couldn't
815 provide you with a message". Other error states seem to exist where
816 ldap_result() didn't give us any message from the server at all, leaving result
817 set to NULL. Apparently, "the error parameters of the LDAP session handle will
818 be set accordingly". That's the best we can do to retrieve an error status; we
819 can't use functions like ldap_result2error because they parse a message from
820 the server, which we didn't get.
822 Annoyingly, the different implementations of LDAP have gone for different
823 methods of handling error codes and generating error messages. */
825 if (rc == -1 || result == NULL)
828 DEBUG(D_lookup) debug_printf("ldap_result failed\n");
830 #if defined LDAP_LIB_SOLARIS || defined LDAP_LIB_OPENLDAP2
831 ldap_get_option(lcp->ld, LDAP_OPT_ERROR_NUMBER, &err);
832 *errmsg = string_sprintf("ldap_result failed: %d, %s",
833 err, ldap_err2string(err));
835 #elif defined LDAP_LIB_NETSCAPE
836 /* Dubious (surely 'matched' is spurious here?) */
837 (void)ldap_get_lderrno(lcp->ld, &matched, &error1);
838 *errmsg = string_sprintf("ldap_result failed: %s (%s)", error1, matched);
840 #else /* UMich LDAP aka OpenLDAP 1.x */
841 *errmsg = string_sprintf("ldap_result failed: %d, %s",
842 lcp->ld->ld_errno, ldap_err2string(lcp->ld->ld_errno));
848 /* A return code that isn't -1 doesn't necessarily mean there were no problems
849 with the search. The message must be an LDAP_RES_SEARCH_RESULT or
850 LDAP_RES_SEARCH_REFERENCE or else it's something we can't handle. Some versions
851 of LDAP do not define LDAP_RES_SEARCH_REFERENCE (LDAP v1 is one, it seems). So
852 we don't provide that functionality when we can't. :-) */
854 if (rc != LDAP_RES_SEARCH_RESULT
855 #ifdef LDAP_RES_SEARCH_REFERENCE
856 && rc != LDAP_RES_SEARCH_REFERENCE
860 *errmsg = string_sprintf("ldap_result returned unexpected code %d", rc);
864 /* We have a result message from the server. This doesn't yet mean all is well.
865 We need to parse the message to find out exactly what's happened. */
867 #if defined LDAP_LIB_SOLARIS || defined LDAP_LIB_OPENLDAP2
869 ldap_parse_rc = ldap_parse_result(lcp->ld, result, &rc, CSS &matched,
870 CSS &error2, NULL, NULL, 0);
871 DEBUG(D_lookup) debug_printf("ldap_parse_result: %d\n", ldap_parse_rc);
872 if (ldap_parse_rc < 0 &&
873 (ldap_parse_rc != LDAP_NO_RESULTS_RETURNED
874 #ifdef LDAP_RES_SEARCH_REFERENCE
875 || ldap_rc != LDAP_RES_SEARCH_REFERENCE
879 *errmsg = string_sprintf("ldap_parse_result failed %d", ldap_parse_rc);
882 error1 = US ldap_err2string(rc);
884 #elif defined LDAP_LIB_NETSCAPE
885 /* Dubious (it doesn't reference 'result' at all!) */
886 rc = ldap_get_lderrno(lcp->ld, &matched, &error1);
888 #else /* UMich LDAP aka OpenLDAP 1.x */
889 rc = ldap_result2error(lcp->ld, result, 0);
890 error1 = ldap_err2string(rc);
891 error2 = lcp->ld->ld_error;
892 matched = lcp->ld->ld_matched;
895 /* Process the status as follows:
897 (1) If we get LDAP_SIZELIMIT_EXCEEDED, just carry on, to return the
898 truncated result list.
900 (2) If we get LDAP_RES_SEARCH_REFERENCE, also just carry on. This was a
901 submitted patch that is reported to "do the right thing" with Solaris
902 LDAP libraries. (The problem it addresses apparently does not occur with
905 (3) The range of errors defined by LDAP_NAME_ERROR generally mean "that
906 object does not, or cannot, exist in the database". For those cases we
909 (4) All other non-successes here are treated as some kind of problem with
910 the lookup, so return DEFER (which is the default in error_yield).
913 DEBUG(D_lookup) debug_printf("ldap_parse_result yielded %d: %s\n",
914 rc, ldap_err2string(rc));
916 if (rc != LDAP_SUCCESS && rc != LDAP_SIZELIMIT_EXCEEDED
917 #ifdef LDAP_RES_SEARCH_REFERENCE
918 && rc != LDAP_RES_SEARCH_REFERENCE
922 *errmsg = string_sprintf("LDAP search failed - error %d: %s%s%s%s%s",
924 (error1 != NULL)? error1 : US"",
925 (error2 != NULL && error2[0] != 0)? US"/" : US"",
926 (error2 != NULL)? error2 : US"",
927 (matched != NULL && matched[0] != 0)? US"/" : US"",
928 (matched != NULL)? matched : US"");
930 #if defined LDAP_NAME_ERROR
931 if (LDAP_NAME_ERROR(rc))
932 #elif defined NAME_ERROR /* OPENLDAP1 calls it this */
935 if (rc == LDAP_NO_SUCH_OBJECT)
939 DEBUG(D_lookup) debug_printf("lookup failure forced\n");
945 /* The search succeeded. Check if we have too many results */
947 if (search_type != SEARCH_LDAP_MULTIPLE && rescount > 1)
949 *errmsg = string_sprintf("LDAP search: more than one entry (%d) was returned "
950 "(filter not specific enough?)", rescount);
951 goto RETURN_ERROR_BREAK;
954 /* Check if we have too few (zero) entries */
958 *errmsg = string_sprintf("LDAP search: no results");
960 goto RETURN_ERROR_BREAK;
963 /* If an entry was found, but it had no attributes, we behave as if no entries
964 were found, that is, the lookup failed. */
966 if (!attribute_found)
968 *errmsg = US"LDAP search: found no attributes";
973 /* Otherwise, it's all worked */
975 DEBUG(D_lookup) debug_printf("LDAP search: returning: %s\n", data);
979 if (result != NULL) ldap_msgfree(result);
980 ldap_free_urldesc(ludp);
989 DEBUG(D_lookup) debug_printf("%s\n", *errmsg);
992 if (result != NULL) ldap_msgfree(result);
993 if (ludp != NULL) ldap_free_urldesc(ludp);
995 #if defined LDAP_LIB_OPENLDAP2
996 if (error2 != NULL) ldap_memfree(error2);
997 if (matched != NULL) ldap_memfree(matched);
1005 /*************************************************
1006 * Internal search control function *
1007 *************************************************/
1009 /* This function is called from eldap_find(), eldapauth_find(), eldapdn_find(),
1010 and eldapm_find() with a difference in the "search_type" argument. It controls
1011 calls to perform_ldap_search() which actually does the work. We call that
1012 repeatedly for certain types of defer in the case when the URL contains no host
1013 name and eldap_default_servers is set to a list of servers to try. This gives
1014 more control than just passing over a list of hosts to ldap_open() because it
1015 handles other kinds of defer as well as just a failure to open. Note that the
1016 URL is defined to contain either zero or one "hostport" only.
1018 Parameter data in addition to the URL can be passed as preceding text in the
1019 string, as items of the form XXX=yyy. The URL itself can be detected because it
1020 must begin "ldapx://", where x is empty, s, or i.
1023 ldap_url the URL to be looked up, optionally preceded by other parameter
1025 search_type SEARCH_LDAP_MULTIPLE allows values from multiple entries
1026 SEARCH_LDAP_SINGLE allows values from one entry only
1027 SEARCH_LDAP_DN gets the DN from one entry
1028 res set to point at the result
1029 errmsg set to point a message if result is not OK
1031 Returns: OK or FAIL or DEFER
1035 control_ldap_search(uschar *ldap_url, int search_type, uschar **res,
1038 BOOL defer_break = FALSE;
1039 int timelimit = LDAP_NO_LIMIT;
1040 int sizelimit = LDAP_NO_LIMIT;
1043 int dereference = LDAP_DEREF_NEVER;
1044 void* referrals = LDAP_OPT_ON;
1045 uschar *url = ldap_url;
1047 uschar *user = NULL;
1048 uschar *password = NULL;
1049 uschar *server, *list;
1052 while (isspace(*url)) url++;
1054 /* Until the string begins "ldap", search for the other parameter settings that
1055 are recognized. They are of the form NAME=VALUE, with the value being
1056 optionally double-quoted. There must still be a space after it, however. No
1057 NAME has the value "ldap". */
1059 while (strncmpic(url, US"ldap", 4) != 0)
1062 while (*url != 0 && *url != '=') url++;
1067 namelen = ++url - name;
1068 value = string_dequote(&url);
1071 if (strncmpic(name, US"USER=", namelen) == 0) user = value;
1072 else if (strncmpic(name, US"PASS=", namelen) == 0) password = value;
1073 else if (strncmpic(name, US"SIZE=", namelen) == 0) sizelimit = Uatoi(value);
1074 else if (strncmpic(name, US"TIME=", namelen) == 0) timelimit = Uatoi(value);
1075 else if (strncmpic(name, US"CONNECT=", namelen) == 0) tcplimit = Uatoi(value);
1076 else if (strncmpic(name, US"NETTIME=", namelen) == 0) tcplimit = Uatoi(value);
1078 /* Don't know if all LDAP libraries have LDAP_OPT_DEREF */
1080 #ifdef LDAP_OPT_DEREF
1081 else if (strncmpic(name, US"DEREFERENCE=", namelen) == 0)
1083 if (strcmpic(value, US"never") == 0) dereference = LDAP_DEREF_NEVER;
1084 else if (strcmpic(value, US"searching") == 0)
1085 dereference = LDAP_DEREF_SEARCHING;
1086 else if (strcmpic(value, US"finding") == 0)
1087 dereference = LDAP_DEREF_FINDING;
1088 if (strcmpic(value, US"always") == 0) dereference = LDAP_DEREF_ALWAYS;
1091 else if (strncmpic(name, US"DEREFERENCE=", namelen) == 0)
1093 *errmsg = string_sprintf("LDAP_OP_DEREF not defined in this LDAP "
1094 "library - cannot use \"dereference\"");
1095 DEBUG(D_lookup) debug_printf("%s\n", *errmsg);
1100 #ifdef LDAP_OPT_REFERRALS
1101 else if (strncmpic(name, US"REFERRALS=", namelen) == 0)
1103 if (strcmpic(value, US"follow") == 0) referrals = LDAP_OPT_ON;
1104 else if (strcmpic(value, US"nofollow") == 0) referrals = LDAP_OPT_OFF;
1107 *errmsg = string_sprintf("LDAP option REFERRALS is not \"follow\" "
1109 DEBUG(D_lookup) debug_printf("%s\n", *errmsg);
1114 else if (strncmpic(name, US"REFERRALS=", namelen) == 0)
1116 *errmsg = string_sprintf("LDAP_OP_REFERRALS not defined in this LDAP "
1117 "library - cannot use \"referrals\"");
1118 DEBUG(D_lookup) debug_printf("%s\n", *errmsg);
1126 string_sprintf("unknown parameter \"%.*s\" precedes LDAP URL",
1128 DEBUG(D_lookup) debug_printf("LDAP query error: %s\n", *errmsg);
1131 while (isspace(*url)) url++;
1135 *errmsg = US"malformed parameter setting precedes LDAP URL";
1136 DEBUG(D_lookup) debug_printf("LDAP query error: %s\n", *errmsg);
1140 /* If user is set, de-URL-quote it. Some LDAP libraries do this for themselves,
1141 but it seems that not all behave like this. The DN for the user is often the
1142 result of ${quote_ldap_dn:...} quoting, which does apply URL quoting, because
1143 that is needed when the DN is used as a base DN in a query. Sigh. This is all
1144 far too complicated. */
1150 for (s = user; *s != 0; s++)
1153 if (*s == '%' && isxdigit(c=s[1]) && isxdigit(d=s[2]))
1158 (((c >= 'a')? (10 + c - 'a') : c - '0') << 4) |
1159 ((d >= 'a')? (10 + d - 'a') : d - '0');
1168 debug_printf("LDAP parameters: user=%s pass=%s size=%d time=%d connect=%d "
1169 "dereference=%d referrals=%s\n", user, password, sizelimit, timelimit,
1170 tcplimit, dereference, (referrals == LDAP_OPT_ON)? "on" : "off");
1172 /* If the request is just to check authentication, some credentials must
1173 be given. The password must not be empty because LDAP binds with an empty
1174 password are considered anonymous, and will succeed on most installations. */
1176 if (search_type == SEARCH_LDAP_AUTH)
1178 if (user == NULL || password == NULL)
1180 *errmsg = US"ldapauth lookups must specify the username and password";
1183 if (password[0] == 0)
1185 DEBUG(D_lookup) debug_printf("Empty password: ldapauth returns FAIL\n");
1190 /* Check for valid ldap url starters */
1193 if (tolower(*p) == 's' || tolower(*p) == 'i') p++;
1194 if (Ustrncmp(p, "://", 3) != 0)
1196 *errmsg = string_sprintf("LDAP URL does not start with \"ldap://\", "
1197 "\"ldaps://\", or \"ldapi://\" (it starts with \"%.16s...\")", url);
1198 DEBUG(D_lookup) debug_printf("LDAP query error: %s\n", *errmsg);
1202 /* No default servers, or URL contains a server name: just one attempt */
1204 if (eldap_default_servers == NULL || p[3] != '/')
1206 return perform_ldap_search(url, NULL, 0, search_type, res, errmsg,
1207 &defer_break, user, password, sizelimit, timelimit, tcplimit, dereference,
1211 /* Loop through the default servers until OK or FAIL */
1213 list = eldap_default_servers;
1214 while ((server = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
1218 uschar *colon = Ustrchr(server, ':');
1222 port = Uatoi(colon+1);
1224 rc = perform_ldap_search(url, server, port, search_type, res, errmsg,
1225 &defer_break, user, password, sizelimit, timelimit, tcplimit, dereference,
1227 if (rc != DEFER || defer_break) return rc;
1235 /*************************************************
1236 * Find entry point *
1237 *************************************************/
1239 /* See local README for interface description. The different kinds of search
1240 are handled by a common function, with a flag to differentiate between them.
1241 The handle and filename arguments are not used. */
1244 eldap_find(void *handle, uschar *filename, uschar *ldap_url, int length,
1245 uschar **result, uschar **errmsg, BOOL *do_cache)
1247 /* Keep picky compilers happy */
1248 do_cache = do_cache;
1249 return(control_ldap_search(ldap_url, SEARCH_LDAP_SINGLE, result, errmsg));
1253 eldapm_find(void *handle, uschar *filename, uschar *ldap_url, int length,
1254 uschar **result, uschar **errmsg, BOOL *do_cache)
1256 /* Keep picky compilers happy */
1257 do_cache = do_cache;
1258 return(control_ldap_search(ldap_url, SEARCH_LDAP_MULTIPLE, result, errmsg));
1262 eldapdn_find(void *handle, uschar *filename, uschar *ldap_url, int length,
1263 uschar **result, uschar **errmsg, BOOL *do_cache)
1265 /* Keep picky compilers happy */
1266 do_cache = do_cache;
1267 return(control_ldap_search(ldap_url, SEARCH_LDAP_DN, result, errmsg));
1271 eldapauth_find(void *handle, uschar *filename, uschar *ldap_url, int length,
1272 uschar **result, uschar **errmsg, BOOL *do_cache)
1274 /* Keep picky compilers happy */
1275 do_cache = do_cache;
1276 return(control_ldap_search(ldap_url, SEARCH_LDAP_AUTH, result, errmsg));
1281 /*************************************************
1282 * Open entry point *
1283 *************************************************/
1285 /* See local README for interface description. */
1288 eldap_open(uschar *filename, uschar **errmsg)
1290 return (void *)(1); /* Just return something non-null */
1295 /*************************************************
1296 * Tidy entry point *
1297 *************************************************/
1299 /* See local README for interface description.
1300 Make sure that eldap_dn does not refer to reclaimed or worse, freed store */
1305 LDAP_CONNECTION *lcp = NULL;
1308 while ((lcp = ldap_connections) != NULL)
1310 DEBUG(D_lookup) debug_printf("unbind LDAP connection to %s:%d\n", lcp->host,
1312 ldap_unbind(lcp->ld);
1313 ldap_connections = lcp->next;
1319 /*************************************************
1320 * Quote entry point *
1321 *************************************************/
1323 /* LDAP quoting is unbelievably messy. For a start, two different levels of
1324 quoting have to be done: LDAP quoting, and URL quoting. The current
1325 specification is the result of a suggestion by Brian Candler. It recognizes
1328 (1) For text that appears in a search filter, the following escapes are
1329 required (see RFC 2254):
1337 Then the entire filter text must be URL-escaped. This kind of quoting is
1338 implemented by ${quote_ldap:....}. Note that we can never have a NULL
1339 in the input string, because that's a terminator.
1341 (2) For a DN that is part of a URL (i.e. the base DN), the characters
1345 must be quoted by backslashing. See RFC 2253. Leading and trailing spaces
1346 must be escaped, as must a leading #. Then the string must be URL-quoted.
1347 This type of quoting is implemented by ${quote_ldap_dn:....}.
1349 For URL quoting, the only characters that need not be quoted are the
1354 All the others must be hexified and preceded by %. This includes the
1355 backslashes used for LDAP quoting.
1357 For a DN that is given in the USER parameter for authentication, we need the
1358 same initial quoting as (2) but in this case, the result must NOT be
1359 URL-escaped, because it isn't a URL. The way this is handled is by
1360 de-URL-quoting the text when processing the USER parameter in
1361 control_ldap_search() above. That means that the same quote operator can be
1362 used. This has the additional advantage that spaces in the DN won't cause
1363 parsing problems. For example:
1365 USER=cn=${quote_ldap_dn:$1},%20dc=example,%20dc=com
1367 should be safe if there are spaces in $1.
1371 s the string to be quoted
1372 opt additional option text or NULL if none
1373 only "dn" is recognized
1375 Returns: the processed string or NULL for a bad option
1380 /* The characters in this string, together with alphanumerics, never need
1381 quoting in any way. */
1383 #define ALWAYS_LITERAL "!$'-._"
1385 /* The special characters in this string do not need to be URL-quoted. The set
1386 is a bit larger than the general literals. */
1388 #define URL_NONQUOTE ALWAYS_LITERAL "()*+"
1390 /* The following macros define the characters that are quoted by quote_ldap and
1391 quote_ldap_dn, respectively. */
1393 #define LDAP_QUOTE "*()\\"
1394 #define LDAP_DN_QUOTE ",+\"\\<>;"
1399 eldap_quote(uschar *s, uschar *opt)
1408 /* Test for a DN quotation. */
1412 if (Ustrcmp(opt, "dn") != 0) return NULL; /* No others recognized */
1416 /* Compute how much extra store we need for the string. This doesn't have to be
1417 exact as long as it isn't an underestimate. The worst case is the addition of 5
1418 extra bytes for a single character. This occurs for certain characters in DNs,
1419 where, for example, < turns into %5C%3C. For simplicity, we just add 5 for each
1420 possibly escaped character. The really fast way would be just to test for
1421 non-alphanumerics, but it is probably better to spot a few others that are
1422 never escaped, because if there are no specials at all, we can avoid copying
1425 while ((c = *t++) != 0)
1428 if (!isalnum(c) && Ustrchr(ALWAYS_LITERAL, c) == NULL) count += 5;
1430 if (count == 0) return s;
1432 /* Get sufficient store to hold the quoted string */
1434 t = quoted = store_get(len + count + 1);
1436 /* Handle plain quote_ldap */
1440 while ((c = *s++) != 0)
1444 if (Ustrchr(LDAP_QUOTE, c) != NULL)
1446 sprintf(CS t, "%%5C%02X", c); /* e.g. * => %5C2A */
1450 if (Ustrchr(URL_NONQUOTE, c) == NULL) /* e.g. ] => %5D */
1452 sprintf(CS t, "%%%02X", c);
1457 *t++ = c; /* unquoted character */
1461 /* Handle quote_ldap_dn */
1465 uschar *ss = s + len;
1467 /* Find the last char before any trailing spaces */
1469 while (ss > s && ss[-1] == ' ') ss--;
1471 /* Quote leading spaces and sharps */
1475 if (*s != ' ' && *s != '#') break;
1476 sprintf(CS t, "%%5C%%%02X", *s);
1480 /* Handle the rest of the string, up to the trailing spaces */
1487 if (Ustrchr(LDAP_DN_QUOTE, c) != NULL)
1489 Ustrncpy(t, "%5C", 3); /* insert \ where needed */
1490 t += 3; /* fall through to check URL */
1492 if (Ustrchr(URL_NONQUOTE, c) == NULL) /* e.g. ] => %5D */
1494 sprintf(CS t, "%%%02X", c);
1499 *t++ = c; /* unquoted character, or non-URL quoted after %5C */
1502 /* Handle the trailing spaces */
1506 Ustrncpy(t, "%5C%20", 6);
1511 /* Terminate the new string and return */
1519 /*************************************************
1520 * Version reporting entry point *
1521 *************************************************/
1523 /* See local README for interface description. */
1525 #include "../version.h"
1528 ldap_version_report(FILE *f)
1531 fprintf(f, "Library version: LDAP: Exim version %s\n", EXIM_VERSION_STR);
1536 static lookup_info ldap_lookup_info = {
1537 US"ldap", /* lookup name */
1538 lookup_querystyle, /* query-style lookup */
1539 eldap_open, /* open function */
1540 NULL, /* check function */
1541 eldap_find, /* find function */
1542 NULL, /* no close function */
1543 eldap_tidy, /* tidy function */
1544 eldap_quote, /* quoting function */
1545 ldap_version_report /* version reporting */
1548 static lookup_info ldapdn_lookup_info = {
1549 US"ldapdn", /* lookup name */
1550 lookup_querystyle, /* query-style lookup */
1551 eldap_open, /* sic */ /* open function */
1552 NULL, /* check function */
1553 eldapdn_find, /* find function */
1554 NULL, /* no close function */
1555 eldap_tidy, /* sic */ /* tidy function */
1556 eldap_quote, /* sic */ /* quoting function */
1557 NULL /* no version reporting (redundant) */
1560 static lookup_info ldapm_lookup_info = {
1561 US"ldapm", /* lookup name */
1562 lookup_querystyle, /* query-style lookup */
1563 eldap_open, /* sic */ /* open function */
1564 NULL, /* check function */
1565 eldapm_find, /* find function */
1566 NULL, /* no close function */
1567 eldap_tidy, /* sic */ /* tidy function */
1568 eldap_quote, /* sic */ /* quoting function */
1569 NULL /* no version reporting (redundant) */
1573 #define ldap_lookup_module_info _lookup_module_info
1576 static lookup_info *_lookup_list[] = { &ldap_lookup_info, &ldapdn_lookup_info, &ldapm_lookup_info };
1577 lookup_module_info ldap_lookup_module_info = { LOOKUP_MODULE_INFO_MAGIC, _lookup_list, 3 };
1579 /* End of lookups/ldap.c */