/* $Cambridge: exim/src/src/lookups/ldap.c,v 1.9 2005/02/17 11:58:27 ph10 Exp $ */ /************************************************* * Exim - an Internet mail transport agent * *************************************************/ /* Copyright (c) University of Cambridge 1995 - 2005 */ /* See the file NOTICE for conditions of use and distribution. */ /* Many thanks to Stuart Lynne for contributing the original code for this driver. Further contibutions from Michael Haardt, Brian Candler, Barry Pederson, Peter Savitch and Christian Kellner. Particular thanks to Brian for researching how to handle the different kinds of error. */ #include "../exim.h" #include "lf_functions.h" #include "ldap.h" /* We can't just compile this code and allow the library mechanism to omit the functions if they are not wanted, because we need to have the LDAP headers available for compiling. Therefore, compile these functions only if LOOKUP_LDAP is defined. However, some compilers don't like compiling empty modules, so keep them happy with a dummy when skipping the rest. Make it reference itself to stop picky compilers complaining that it is unused, and put in a dummy argument to stop even pickier compilers complaining about infinite loops. */ #ifndef LOOKUP_LDAP static void dummy(int x) { dummy(x-1); } #else /* Include LDAP headers */ #include #include /* Annoyingly, the different LDAP libraries handle errors in different ways, and some other things too. There doesn't seem to be an automatic way of distinguishing between them. Local/Makefile should contain a setting of LDAP_LIB_TYPE, which in turn causes appropriate macros to be defined for the different kinds. Those that matter are: LDAP_LIB_NETSCAPE LDAP_LIB_SOLARIS with synonym LDAP_LIB_SOLARIS7 LDAP_LIB_OPENLDAP2 These others may be defined, but are in fact the default, so are not tested: LDAP_LIB_UMICHIGAN LDAP_LIB_OPENLDAP1 */ #if defined(LDAP_LIB_SOLARIS7) && ! defined(LDAP_LIB_SOLARIS) #define LDAP_LIB_SOLARIS #endif /* Just in case LDAP_NO_LIMIT is not defined by some of these libraries. */ #ifndef LDAP_NO_LIMIT #define LDAP_NO_LIMIT 0 #endif /* Just in case LDAP_DEREF_NEVER is not defined */ #ifndef LDAP_DEREF_NEVER #define LDAP_DEREF_NEVER 0 #endif /* Four types of LDAP search are implemented */ #define SEARCH_LDAP_MULTIPLE 0 /* Get attributes from multiple entries */ #define SEARCH_LDAP_SINGLE 1 /* Get attributes from one entry only */ #define SEARCH_LDAP_DN 2 /* Get just the DN from one entry */ #define SEARCH_LDAP_AUTH 3 /* Just checking for authentication */ /* In all 4 cases, the DN is left in $ldap_dn (which post-dates the SEARCH_LDAP_DN lookup). */ /* Structure and anchor for caching connections. */ typedef struct ldap_connection { struct ldap_connection *next; uschar *host; uschar *user; uschar *password; BOOL bound; int port; LDAP *ld; } LDAP_CONNECTION; static LDAP_CONNECTION *ldap_connections = NULL; /************************************************* * Internal search function * *************************************************/ /* This is the function that actually does the work. It is called (indirectly via control_ldap_search) from eldap_find(), eldapauth_find(), eldapdn_find(), and eldapm_find(), with a difference in the "search_type" argument. The case of eldapauth_find() is special in that all it does is do authentication, returning OK or FAIL as appropriate. This isn't used as a lookup. Instead, it is called from expand.c as an expansion condition test. The DN from a successful lookup is placed in $ldap_dn. This feature postdates the provision of the SEARCH_LDAP_DN facility for returning just the DN as the data. Arguments: ldap_url the URL to be looked up server server host name, when URL contains none s_port server port, used when URL contains no name search_type SEARCH_LDAP_MULTIPLE allows values from multiple entries SEARCH_LDAP_SINGLE allows values from one entry only SEARCH_LDAP_DN gets the DN from one entry res set to point at the result (not used for ldapauth) errmsg set to point a message if result is not OK defer_break set TRUE if no more servers to be tried after a DEFER user user name for authentication, or NULL password password for authentication, or NULL sizelimit max number of entries returned, or 0 for no limit timelimit max time to wait, or 0 for no limit tcplimit max time for network activity, e.g. connect, or 0 for OS default deference the dereference option, which is one of LDAP_DEREF_{NEVER,SEARCHING,FINDING,ALWAYS} Returns: OK or FAIL or DEFER FAIL is given only if a lookup was performed successfully, but returned no data. */ static int perform_ldap_search(uschar *ldap_url, uschar *server, int s_port, int search_type, uschar **res, uschar **errmsg, BOOL *defer_break, uschar *user, uschar *password, int sizelimit, int timelimit, int tcplimit, int dereference) { LDAPURLDesc *ludp = NULL; LDAPMessage *result = NULL; BerElement *ber; LDAP_CONNECTION *lcp; struct timeval timeout; struct timeval *timeoutptr = NULL; uschar *attr; uschar **attrp; uschar *data = NULL; uschar *dn = NULL; uschar *host; uschar **values; uschar **firstval; uschar porttext[16]; uschar *error1 = NULL; /* string representation of errcode (static) */ uschar *error2 = NULL; /* error message from the server */ uschar *matched = NULL; /* partially matched DN */ int attr_count = 0; int error_yield = DEFER; int msgid; int rc, ldap_rc, ldap_parse_rc; int port; int ptr = 0; int rescount = 0; int size = 0; BOOL attribute_found = FALSE; BOOL ldapi = FALSE; DEBUG(D_lookup) debug_printf("perform_ldap_search: ldap%s URL = \"%s\" server=%s port=%d " "sizelimit=%d timelimit=%d tcplimit=%d\n", (search_type == SEARCH_LDAP_MULTIPLE)? "m" : (search_type == SEARCH_LDAP_DN)? "dn" : (search_type == SEARCH_LDAP_AUTH)? "auth" : "", ldap_url, server, s_port, sizelimit, timelimit, tcplimit); /* Check if LDAP thinks the URL is a valid LDAP URL. We assume that if the LDAP library that is in use doesn't recognize, say, "ldapi", it will barf here. */ if (!ldap_is_ldap_url(CS ldap_url)) { *errmsg = string_sprintf("ldap_is_ldap_url: not an LDAP url \"%s\"\n", ldap_url); goto RETURN_ERROR_BREAK; } /* Parse the URL */ if ((rc = ldap_url_parse(CS ldap_url, &ludp)) != 0) { *errmsg = string_sprintf("ldap_url_parse: (error %d) parsing \"%s\"\n", rc, ldap_url); goto RETURN_ERROR_BREAK; } /* If the host name is empty, take it from the separate argument, if one is given. OpenLDAP 2.0.6 sets an unset hostname to "" rather than empty, but expects NULL later in ldap_init() to mean "default", annoyingly. In OpenLDAP 2.0.11 this has changed (it uses NULL). */ if ((ludp->lud_host == NULL || ludp->lud_host[0] == 0) && server != NULL) { host = server; port = s_port; } else { host = US ludp->lud_host; if (host != NULL && host[0] == 0) host = NULL; port = ludp->lud_port; } DEBUG(D_lookup) debug_printf("after ldap_url_parse: host=%s port=%d\n", host, port); if (port == 0) port = LDAP_PORT; /* Default if none given */ sprintf(CS porttext, ":%d", port); /* For messages */ /* If the "host name" is actually a path, we are going to connect using a Unix socket, regardless of whether "ldapi" was actually specified or not. This means that a Unix socket can be declared in eldap_default_servers, and "traditional" LDAP queries using just "ldap" can be used ("ldaps" is similarly overridden). The path may start with "/" or it may already be escaped as "%2F" if it was actually declared that way in eldap_default_servers. (I did it that way the first time.) If the host name is not a path, the use of "ldapi" causes an error, except in the default case. (But lud_scheme doesn't seem to exist in older libraries.) */ if (host != NULL) { if ((host[0] == '/' || Ustrncmp(host, "%2F", 3) == 0)) { ldapi = TRUE; porttext[0] = 0; /* Remove port from messages */ } #if defined LDAP_LIB_OPENLDAP2 else if (strncmp(ludp->lud_scheme, "ldapi", 5) == 0) { *errmsg = string_sprintf("ldapi requires an absolute path (\"%s\" given)", host); goto RETURN_ERROR; } #endif } /* Count the attributes; we need this later to tell us how to format results */ for (attrp = USS ludp->lud_attrs; attrp != NULL && *attrp != NULL; attrp++) attr_count++; /* See if we can find a cached connection to this host. The port is not relevant for ldapi. The host name pointer is set to NULL if no host was given (implying the library default), rather than to the empty string. Note that in this case, there is no difference between ldap and ldapi. */ for (lcp = ldap_connections; lcp != NULL; lcp = lcp->next) { if ((host == NULL) != (lcp->host == NULL) || (host != NULL && strcmpic(lcp->host, host) != 0)) continue; if (ldapi || port == lcp->port) break; } /* Use this network timeout in any requests. */ if (tcplimit > 0) { timeout.tv_sec = tcplimit; timeout.tv_usec = 0; timeoutptr = &timeout; } /* If no cached connection found, we must open a connection to the server. If the server name is actually an absolute path, we set ldapi=TRUE above. This requests connection via a Unix socket. However, as far as I know, only OpenLDAP supports the use of sockets, and the use of ldap_initialize(). */ if (lcp == NULL) { LDAP *ld; /* --------------------------- OpenLDAP ------------------------ */ /* There seems to be a preference under OpenLDAP for ldap_initialize() instead of ldap_init(), though I have as yet been unable to find documentation that says this. (OpenLDAP documentation is sparse to non-existent). So we handle OpenLDAP differently here. Also, support for ldapi seems to be OpenLDAP-only at present. */ #ifdef LDAP_LIB_OPENLDAP2 /* We now need an empty string for the default host. Get some store in which to build a URL for ldap_initialize(). In the ldapi case, it can't be bigger than (9 + 3*Ustrlen(shost)), whereas in the other cases it can't be bigger than the host name + "ldaps:///" plus : and a port number, say 20 + the length of the host name. What we get should accommodate both, easily. */ uschar *shost = (host == NULL)? US"" : host; uschar *init_url = store_get(20 + 3 * Ustrlen(shost)); uschar *init_ptr; /* Handle connection via Unix socket ("ldapi"). We build a basic LDAP URI to contain the path name, with slashes escaped as %2F. */ if (ldapi) { int ch; init_ptr = init_url + 8; Ustrcpy(init_url, "ldapi://"); while ((ch = *shost++) != 0) { if (ch == '/') { Ustrncpy(init_ptr, "%2F", 3); init_ptr += 3; } else *init_ptr++ = ch; } *init_ptr = 0; } /* This is not an ldapi call. Just build a URI with the protocol type, host name, and port. */ else { init_ptr = Ustrchr(ldap_url, '/'); Ustrncpy(init_url, ldap_url, init_ptr - ldap_url); init_ptr = init_url + (init_ptr - ldap_url); sprintf(CS init_ptr, "//%s:%d/", shost, port); } /* Call ldap_initialize() and check the result */ DEBUG(D_lookup) debug_printf("ldap_initialize with URL %s\n", init_url); rc = ldap_initialize(&ld, CS init_url); if (rc != LDAP_SUCCESS) { *errmsg = string_sprintf("ldap_initialize: (error %d) URL \"%s\"\n", rc, init_url); goto RETURN_ERROR; } store_reset(init_url); /* Might as well save memory when we can */ /* ------------------------- Not OpenLDAP ---------------------- */ /* For libraries other than OpenLDAP, use ldap_init(). */ #else /* LDAP_LIB_OPENLDAP2 */ ld = ldap_init(CS host, port); #endif /* LDAP_LIB_OPENLDAP2 */ /* -------------------------------------------------------------- */ /* Handle failure to initialize */ if (ld == NULL) { *errmsg = string_sprintf("failed to initialize for LDAP server %s%s - %s", host, porttext, strerror(errno)); goto RETURN_ERROR; } /* Set the TCP connect time limit if available. This is something that is in Netscape SDK v4.1; I don't know about other libraries. */ #ifdef LDAP_X_OPT_CONNECT_TIMEOUT if (tcplimit > 0) { int timeout1000 = tcplimit*1000; ldap_set_option(ld, LDAP_X_OPT_CONNECT_TIMEOUT, (void *)&timeout1000); } else { int notimeout = LDAP_X_IO_TIMEOUT_NO_TIMEOUT; ldap_set_option(ld, LDAP_X_OPT_CONNECT_TIMEOUT, (void *)¬imeout); } #endif /* Set the TCP connect timeout. This works with OpenLDAP 2.2.14. */ #ifdef LDAP_OPT_NETWORK_TIMEOUT if (tcplimit > 0) ldap_set_option(ld, LDAP_OPT_NETWORK_TIMEOUT, (void *)timeoutptr); #endif /* I could not get TLS to work until I set the version to 3. That version seems to be the default nowadays. The RFC is dated 1997, so I would hope that all the LDAP libraries support it. Therefore, if eldap_version hasn't been set, go for v3 if we can. */ if (eldap_version < 0) { #ifdef LDAP_VERSION3 eldap_version = LDAP_VERSION3; #else eldap_version = 2; #endif } #ifdef LDAP_OPT_PROTOCOL_VERSION ldap_set_option(ld, LDAP_OPT_PROTOCOL_VERSION, (void *)&eldap_version); #endif DEBUG(D_lookup) debug_printf("initialized for LDAP (v%d) server %s%s\n", eldap_version, host, porttext); /* If not using ldapi and TLS is available, set appropriate TLS options: hard for "ldaps" and soft otherwise. */ #ifdef LDAP_OPT_X_TLS if (!ldapi) { int tls_option; if (strncmp(ludp->lud_scheme, "ldaps", 5) == 0) { tls_option = LDAP_OPT_X_TLS_HARD; DEBUG(D_lookup) debug_printf("LDAP_OPT_X_TLS_HARD set\n"); } else { tls_option = LDAP_OPT_X_TLS_TRY; DEBUG(D_lookup) debug_printf("LDAP_OPT_X_TLS_TRY set\n"); } ldap_set_option(ld, LDAP_OPT_X_TLS, (void *)&tls_option); } #endif /* LDAP_OPT_X_TLS */ /* Now add this connection to the chain of cached connections */ lcp = store_get(sizeof(LDAP_CONNECTION)); lcp->host = (host == NULL)? NULL : string_copy(host); lcp->bound = FALSE; lcp->user = NULL; lcp->password = NULL; lcp->port = port; lcp->ld = ld; lcp->next = ldap_connections; ldap_connections = lcp; } /* Found cached connection */ else { DEBUG(D_lookup) debug_printf("re-using cached connection to LDAP server %s%s\n", host, porttext); } /* Bind with the user/password supplied, or an anonymous bind if these values are NULL, unless a cached connection is already bound with the same values. */ if (!lcp->bound || (lcp->user == NULL && user != NULL) || (lcp->user != NULL && user == NULL) || (lcp->user != NULL && user != NULL && Ustrcmp(lcp->user, user) != 0) || (lcp->password == NULL && password != NULL) || (lcp->password != NULL && password == NULL) || (lcp->password != NULL && password != NULL && Ustrcmp(lcp->password, password) != 0)) { DEBUG(D_lookup) debug_printf("%sbinding with user=%s password=%s\n", (lcp->bound)? "re-" : "", user, password); if ((msgid = ldap_bind(lcp->ld, CS user, CS password, LDAP_AUTH_SIMPLE)) == -1) { *errmsg = string_sprintf("failed to bind the LDAP connection to server " "%s%s - ldap_bind() returned -1", host, porttext); goto RETURN_ERROR; } if ((rc = ldap_result( lcp->ld, msgid, 1, timeoutptr, &result )) <= 0) { *errmsg = string_sprintf("failed to bind the LDAP connection to server " "%s%s - LDAP error: %s", host, porttext, rc == -1 ? "result retrieval failed" : "timeout" ); result = NULL; goto RETURN_ERROR; } rc = ldap_result2error( lcp->ld, result, 0 ); /* Invalid credentials when just checking credentials returns FAIL. This stops any further servers being tried. */ if (search_type == SEARCH_LDAP_AUTH && rc == LDAP_INVALID_CREDENTIALS) { DEBUG(D_lookup) debug_printf("Invalid credentials: ldapauth returns FAIL\n"); error_yield = FAIL; goto RETURN_ERROR_NOMSG; } /* Otherwise we have a problem that doesn't stop further servers from being tried. */ if (rc != LDAP_SUCCESS) { *errmsg = string_sprintf("failed to bind the LDAP connection to server " "%s%s - LDAP error %d: %s", host, porttext, rc, ldap_err2string(rc)); goto RETURN_ERROR; } /* Successful bind */ lcp->bound = TRUE; lcp->user = (user == NULL)? NULL : string_copy(user); lcp->password = (password == NULL)? NULL : string_copy(password); ldap_msgfree(result); result = NULL; } /* If we are just checking credentials, return OK. */ if (search_type == SEARCH_LDAP_AUTH) { DEBUG(D_lookup) debug_printf("Bind succeeded: ldapauth returns OK\n"); goto RETURN_OK; } /* Before doing the search, set the time and size limits (if given). Here again the different implementations of LDAP have chosen to do things differently. */ #if defined(LDAP_OPT_SIZELIMIT) ldap_set_option(lcp->ld, LDAP_OPT_SIZELIMIT, (void *)&sizelimit); ldap_set_option(lcp->ld, LDAP_OPT_TIMELIMIT, (void *)&timelimit); #else lcp->ld->ld_sizelimit = sizelimit; lcp->ld->ld_timelimit = timelimit; #endif /* Similarly for dereferencing aliases. Don't know if this is possible on an LDAP library without LDAP_OPT_DEREF. */ #if defined(LDAP_OPT_DEREF) ldap_set_option(lcp->ld, LDAP_OPT_DEREF, (void *)&dereference); #endif /* Start the search on the server. */ DEBUG(D_lookup) debug_printf("Start search\n"); msgid = ldap_search(lcp->ld, ludp->lud_dn, ludp->lud_scope, ludp->lud_filter, ludp->lud_attrs, 0); if (msgid == -1) { #if defined LDAP_LIB_SOLARIS || defined LDAP_LIB_OPENLDAP2 int err; ldap_get_option(lcp->ld, LDAP_OPT_ERROR_NUMBER, &err); *errmsg = string_sprintf("ldap_search failed: %d, %s", err, ldap_err2string(err)); #else *errmsg = string_sprintf("ldap_search failed"); #endif goto RETURN_ERROR; } /* Loop to pick up results as they come in, setting a timeout if one was given. */ while ((rc = ldap_result(lcp->ld, msgid, 0, timeoutptr, &result)) == LDAP_RES_SEARCH_ENTRY) { LDAPMessage *e; DEBUG(D_lookup) debug_printf("ldap_result loop\n"); for(e = ldap_first_entry(lcp->ld, result); e != NULL; e = ldap_next_entry(lcp->ld, e)) { uschar *new_dn; BOOL insert_space = FALSE; DEBUG(D_lookup) debug_printf("LDAP entry loop\n"); rescount++; /* Count results */ /* Results for multiple entries values are separated by newlines. */ if (data != NULL) data = string_cat(data, &size, &ptr, US"\n", 1); /* Get the DN from the last result. */ new_dn = US ldap_get_dn(lcp->ld, e); if (new_dn != NULL) { if (dn != NULL) { #if defined LDAP_LIB_NETSCAPE || defined LDAP_LIB_OPENLDAP2 ldap_memfree(dn); #else /* OPENLDAP 1, UMich, Solaris */ free(dn); #endif } /* Save for later */ dn = new_dn; } /* If the data we want is actually the DN rather than any attribute values, (an "ldapdn" search) add it to the data string. If there are multiple entries, the DNs will be concatenated, but we test for this case below, as for SEARCH_LDAP_SINGLE, and give an error. */ if (search_type == SEARCH_LDAP_DN) /* Do not amalgamate these into one */ { /* condition, because of the else */ if (new_dn != NULL) /* below, that's for the first only */ { data = string_cat(data, &size, &ptr, new_dn, Ustrlen(new_dn)); data[ptr] = 0; attribute_found = TRUE; } } /* Otherwise, loop through the entry, grabbing attribute values. If there's only one attribute being retrieved, no attribute name is given, and the result is not quoted. Multiple values are separated by (comma, space). If more than one attribute is being retrieved, the data is given as a sequence of name=value pairs, with the value always in quotes. If there are multiple values, they are given within the quotes, comma separated. */ else for (attr = US ldap_first_attribute(lcp->ld, e, &ber); attr != NULL; attr = US ldap_next_attribute(lcp->ld, e, ber)) { if (attr[0] != 0) { /* Get array of values for this attribute. */ if ((firstval = values = USS ldap_get_values(lcp->ld, e, CS attr)) != NULL) { if (attr_count != 1) { if (insert_space) data = string_cat(data, &size, &ptr, US" ", 1); else insert_space = TRUE; data = string_cat(data, &size, &ptr, attr, Ustrlen(attr)); data = string_cat(data, &size, &ptr, US"=\"", 2); } while (*values != NULL) { uschar *value = *values; int len = Ustrlen(value); DEBUG(D_lookup) debug_printf("LDAP attr loop %s:%s\n", attr, value); if (values != firstval) data = string_cat(data, &size, &ptr, US", ", 2); /* For multiple attributes, the data is in quotes. We must escape internal quotes, backslashes, newlines. */ if (attr_count != 1) { int j; for (j = 0; j < len; j++) { if (value[j] == '\n') data = string_cat(data, &size, &ptr, US"\\n", 2); else { if (value[j] == '\"' || value[j] == '\\') data = string_cat(data, &size, &ptr, US"\\", 1); data = string_cat(data, &size, &ptr, value+j, 1); } } } /* For single attributes, copy the value verbatim */ else data = string_cat(data, &size, &ptr, value, len); /* Move on to the next value */ values++; attribute_found = TRUE; } /* Closing quote at the end of the data for a named attribute. */ if (attr_count != 1) data = string_cat(data, &size, &ptr, US"\"", 1); /* Free the values */ ldap_value_free(CSS firstval); } } #if defined LDAP_LIB_NETSCAPE || defined LDAP_LIB_OPENLDAP2 /* Netscape and OpenLDAP2 LDAP's attrs are dynamically allocated and need to be freed. UMich LDAP stores them in static storage and does not require this. */ ldap_memfree(attr); #endif } /* End "for" loop for extracting attributes from an entry */ } /* End "for" loop for extracting entries from a result */ /* Free the result */ ldap_msgfree(result); result = NULL; } /* End "while" loop for multiple results */ /* Terminate the dynamic string that we have built and reclaim unused store */ if (data != NULL) { data[ptr] = 0; store_reset(data + ptr + 1); } /* Copy the last dn into eldap_dn */ if (dn != NULL) { eldap_dn = string_copy(dn); #if defined LDAP_LIB_NETSCAPE || defined LDAP_LIB_OPENLDAP2 ldap_memfree(dn); #else /* OPENLDAP 1, UMich, Solaris */ free(dn); #endif } DEBUG(D_lookup) debug_printf("search ended by ldap_result yielding %d\n",rc); if (rc == 0) { *errmsg = US"ldap_result timed out"; goto RETURN_ERROR; } /* A return code of -1 seems to mean "ldap_result failed internally or couldn't provide you with a message". Other error states seem to exist where ldap_result() didn't give us any message from the server at all, leaving result set to NULL. Apparently, "the error parameters of the LDAP session handle will be set accordingly". That's the best we can do to retrieve an error status; we can't use functions like ldap_result2error because they parse a message from the server, which we didn't get. Annoyingly, the different implementations of LDAP have gone for different methods of handling error codes and generating error messages. */ if (rc == -1 || result == NULL) { int err; DEBUG(D_lookup) debug_printf("ldap_result failed\n"); #if defined LDAP_LIB_SOLARIS || defined LDAP_LIB_OPENLDAP2 ldap_get_option(lcp->ld, LDAP_OPT_ERROR_NUMBER, &err); *errmsg = string_sprintf("ldap_result failed: %d, %s", err, ldap_err2string(err)); #elif defined LDAP_LIB_NETSCAPE /* Dubious (surely 'matched' is spurious here?) */ (void)ldap_get_lderrno(lcp->ld, &matched, &error1); *errmsg = string_sprintf("ldap_result failed: %s (%s)", error1, matched); #else /* UMich LDAP aka OpenLDAP 1.x */ *errmsg = string_sprintf("ldap_result failed: %d, %s", lcp->ld->ld_errno, ldap_err2string(lcp->ld->ld_errno)); #endif goto RETURN_ERROR; } /* A return code that isn't -1 doesn't necessarily mean there were no problems with the search. The message must be an LDAP_RES_SEARCH_RESULT or LDAP_RES_SEARCH_REFERENCE or else it's something we can't handle. Some versions of LDAP do not define LDAP_RES_SEARCH_REFERENCE (LDAP v1 is one, it seems). So we don't provide that functionality when we can't. :-) */ if (rc != LDAP_RES_SEARCH_RESULT #ifdef LDAP_RES_SEARCH_REFERENCE && rc != LDAP_RES_SEARCH_REFERENCE #endif ) { *errmsg = string_sprintf("ldap_result returned unexpected code %d", rc); goto RETURN_ERROR; } /* We have a result message from the server. This doesn't yet mean all is well. We need to parse the message to find out exactly what's happened. */ #if defined LDAP_LIB_SOLARIS || defined LDAP_LIB_OPENLDAP2 ldap_rc = rc; ldap_parse_rc = ldap_parse_result(lcp->ld, result, &rc, CSS &matched, CSS &error2, NULL, NULL, 0); DEBUG(D_lookup) debug_printf("ldap_parse_result: %d\n", ldap_parse_rc); if (ldap_parse_rc < 0 && (ldap_parse_rc != LDAP_NO_RESULTS_RETURNED #ifdef LDAP_RES_SEARCH_REFERENCE || ldap_rc != LDAP_RES_SEARCH_REFERENCE #endif )) { *errmsg = string_sprintf("ldap_parse_result failed %d", ldap_parse_rc); goto RETURN_ERROR; } error1 = US ldap_err2string(rc); #elif defined LDAP_LIB_NETSCAPE /* Dubious (it doesn't reference 'result' at all!) */ rc = ldap_get_lderrno(lcp->ld, &matched, &error1); #else /* UMich LDAP aka OpenLDAP 1.x */ rc = ldap_result2error(lcp->ld, result, 0); error1 = ldap_err2string(rc); error2 = lcp->ld->ld_error; matched = lcp->ld->ld_matched; #endif /* Process the status as follows: (1) If we get LDAP_SIZELIMIT_EXCEEDED, just carry on, to return the truncated result list. (2) The range of errors defined by LDAP_NAME_ERROR generally mean "that object does not, or cannot, exist in the database". For those cases we fail the lookup. (3) All other non-successes here are treated as some kind of problem with the lookup, so return DEFER (which is the default in error_yield). */ DEBUG(D_lookup) debug_printf("ldap_parse_result yielded %d: %s\n", rc, ldap_err2string(rc)); if (rc != LDAP_SUCCESS && rc != LDAP_SIZELIMIT_EXCEEDED) { *errmsg = string_sprintf("LDAP search failed - error %d: %s%s%s%s%s", rc, (error1 != NULL)? error1 : US"", (error2 != NULL && error2[0] != 0)? US"/" : US"", (error2 != NULL)? error2 : US"", (matched != NULL && matched[0] != 0)? US"/" : US"", (matched != NULL)? matched : US""); #if defined LDAP_NAME_ERROR if (LDAP_NAME_ERROR(rc)) #elif defined NAME_ERROR /* OPENLDAP1 calls it this */ if (NAME_ERROR(rc)) #else if (rc == LDAP_NO_SUCH_OBJECT) #endif { DEBUG(D_lookup) debug_printf("lookup failure forced\n"); error_yield = FAIL; } goto RETURN_ERROR; } /* The search succeeded. Check if we have too many results */ if (search_type != SEARCH_LDAP_MULTIPLE && rescount > 1) { *errmsg = string_sprintf("LDAP search: more than one entry (%d) was returned " "(filter not specific enough?)", rescount); goto RETURN_ERROR_BREAK; } /* Check if we have too few (zero) entries */ if (rescount < 1) { *errmsg = string_sprintf("LDAP search: no results"); error_yield = FAIL; goto RETURN_ERROR_BREAK; } /* If an entry was found, but it had no attributes, we behave as if no entries were found, that is, the lookup failed. */ if (!attribute_found) { *errmsg = US"LDAP search: found no attributes"; error_yield = FAIL; goto RETURN_ERROR; } /* Otherwise, it's all worked */ DEBUG(D_lookup) debug_printf("LDAP search: returning: %s\n", data); *res = data; RETURN_OK: if (result != NULL) ldap_msgfree(result); ldap_free_urldesc(ludp); return OK; /* Error returns */ RETURN_ERROR_BREAK: *defer_break = TRUE; RETURN_ERROR: DEBUG(D_lookup) debug_printf("%s\n", *errmsg); RETURN_ERROR_NOMSG: if (result != NULL) ldap_msgfree(result); if (ludp != NULL) ldap_free_urldesc(ludp); #if defined LDAP_LIB_OPENLDAP2 if (error2 != NULL) ldap_memfree(error2); if (matched != NULL) ldap_memfree(matched); #endif return error_yield; } /************************************************* * Internal search control function * *************************************************/ /* This function is called from eldap_find(), eldapauth_find(), eldapdn_find(), and eldapm_find() with a difference in the "search_type" argument. It controls calls to perform_ldap_search() which actually does the work. We call that repeatedly for certain types of defer in the case when the URL contains no host name and eldap_default_servers is set to a list of servers to try. This gives more control than just passing over a list of hosts to ldap_open() because it handles other kinds of defer as well as just a failure to open. Note that the URL is defined to contain either zero or one "hostport" only. Parameter data in addition to the URL can be passed as preceding text in the string, as items of the form XXX=yyy. The URL itself can be detected because it must begin "ldapx://", where x is empty, s, or i. Arguments: ldap_url the URL to be looked up, optionally preceded by other parameter settings search_type SEARCH_LDAP_MULTIPLE allows values from multiple entries SEARCH_LDAP_SINGLE allows values from one entry only SEARCH_LDAP_DN gets the DN from one entry res set to point at the result errmsg set to point a message if result is not OK Returns: OK or FAIL or DEFER */ static int control_ldap_search(uschar *ldap_url, int search_type, uschar **res, uschar **errmsg) { BOOL defer_break = FALSE; int timelimit = LDAP_NO_LIMIT; int sizelimit = LDAP_NO_LIMIT; int tcplimit = 0; int dereference = LDAP_DEREF_NEVER; int sep = 0; uschar *url = ldap_url; uschar *p; uschar *user = NULL; uschar *password = NULL; uschar *server, *list; uschar buffer[512]; while (isspace(*url)) url++; /* Until the string begins "ldap", search for the other parameter settings that are recognized. They are of the form NAME=VALUE, with the value being optionally double-quoted. There must still be a space after it, however. No NAME has the value "ldap". */ while (strncmpic(url, US"ldap", 4) != 0) { uschar *name = url; while (*url != 0 && *url != '=') url++; if (*url == '=') { int namelen; uschar *value; namelen = ++url - name; value = string_dequote(&url); if (isspace(*url)) { if (strncmpic(name, US"USER=", namelen) == 0) user = value; else if (strncmpic(name, US"PASS=", namelen) == 0) password = value; else if (strncmpic(name, US"SIZE=", namelen) == 0) sizelimit = Uatoi(value); else if (strncmpic(name, US"TIME=", namelen) == 0) timelimit = Uatoi(value); else if (strncmpic(name, US"CONNECT=", namelen) == 0) tcplimit = Uatoi(value); else if (strncmpic(name, US"NETTIME=", namelen) == 0) tcplimit = Uatoi(value); /* Don't know if all LDAP libraries have LDAP_OPT_DEREF */ #ifdef LDAP_OPT_DEREF else if (strncmpic(name, US"DEREFERENCE=", namelen) == 0) { if (strcmpic(value, US"never") == 0) dereference = LDAP_DEREF_NEVER; else if (strcmpic(value, US"searching") == 0) dereference = LDAP_DEREF_SEARCHING; else if (strcmpic(value, US"finding") == 0) dereference = LDAP_DEREF_FINDING; if (strcmpic(value, US"always") == 0) dereference = LDAP_DEREF_ALWAYS; } #else else if (strncmpic(name, US"DEREFERENCE=", namelen) == 0) { *errmsg = string_sprintf("LDAP_OP_DEREF not defined in this LDAP " "library - cannot use \"dereference\""); DEBUG(D_lookup) debug_printf("%s\n", *errmsg); return DEFER; } #endif else { *errmsg = string_sprintf("unknown parameter \"%.*s\" precedes LDAP URL", namelen, name); DEBUG(D_lookup) debug_printf("LDAP query error: %s\n", *errmsg); return DEFER; } while (isspace(*url)) url++; continue; } } *errmsg = US"malformed parameter setting precedes LDAP URL"; DEBUG(D_lookup) debug_printf("LDAP query error: %s\n", *errmsg); return DEFER; } /* If user is set, de-URL-quote it. Some LDAP libraries do this for themselves, but it seems that not all behave like this. The DN for the user is often the result of ${quote_ldap_dn:...} quoting, which does apply URL quoting, because that is needed when the DN is used as a base DN in a query. Sigh. This is all far too complicated. */ if (user != NULL) { uschar *s; uschar *t = user; for (s = user; *s != 0; s++) { int c, d; if (*s == '%' && isxdigit(c=s[1]) && isxdigit(d=s[2])) { c = tolower(c); d = tolower(d); *t++ = (((c >= 'a')? (10 + c - 'a') : c - '0') << 4) | ((d >= 'a')? (10 + d - 'a') : d - '0'); s += 2; } else *t++ = *s; } *t = 0; } DEBUG(D_lookup) debug_printf("LDAP parameters: user=%s pass=%s size=%d time=%d connect=%d " "dereference=%d\n", user, password, sizelimit, timelimit, tcplimit, dereference); /* If the request is just to check authentication, some credentials must be given. The password must not be empty because LDAP binds with an empty password are considered anonymous, and will succeed on most installations. */ if (search_type == SEARCH_LDAP_AUTH) { if (user == NULL || password == NULL) { *errmsg = US"ldapauth lookups must specify the username and password"; return DEFER; } if (password[0] == 0) { DEBUG(D_lookup) debug_printf("Empty password: ldapauth returns FAIL\n"); return FAIL; } } /* Check for valid ldap url starters */ p = url + 4; if (tolower(*p) == 's' || tolower(*p) == 'i') p++; if (Ustrncmp(p, "://", 3) != 0) { *errmsg = string_sprintf("LDAP URL does not start with \"ldap://\", " "\"ldaps://\", or \"ldapi://\" (it starts with \"%.16s...\")", url); DEBUG(D_lookup) debug_printf("LDAP query error: %s\n", *errmsg); return DEFER; } /* No default servers, or URL contains a server name: just one attempt */ if (eldap_default_servers == NULL || p[3] != '/') { return perform_ldap_search(url, NULL, 0, search_type, res, errmsg, &defer_break, user, password, sizelimit, timelimit, tcplimit, dereference); } /* Loop through the default servers until OK or FAIL */ list = eldap_default_servers; while ((server = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL) { int rc; int port = 0; uschar *colon = Ustrchr(server, ':'); if (colon != NULL) { *colon = 0; port = Uatoi(colon+1); } rc = perform_ldap_search(url, server, port, search_type, res, errmsg, &defer_break, user, password, sizelimit, timelimit, tcplimit, dereference); if (rc != DEFER || defer_break) return rc; } return DEFER; } /************************************************* * Find entry point * *************************************************/ /* See local README for interface description. The different kinds of search are handled by a common function, with a flag to differentiate between them. The handle and filename arguments are not used. */ int eldap_find(void *handle, uschar *filename, uschar *ldap_url, int length, uschar **result, uschar **errmsg, BOOL *do_cache) { /* Keep picky compilers happy */ do_cache = do_cache; return(control_ldap_search(ldap_url, SEARCH_LDAP_SINGLE, result, errmsg)); } int eldapm_find(void *handle, uschar *filename, uschar *ldap_url, int length, uschar **result, uschar **errmsg, BOOL *do_cache) { /* Keep picky compilers happy */ do_cache = do_cache; return(control_ldap_search(ldap_url, SEARCH_LDAP_MULTIPLE, result, errmsg)); } int eldapdn_find(void *handle, uschar *filename, uschar *ldap_url, int length, uschar **result, uschar **errmsg, BOOL *do_cache) { /* Keep picky compilers happy */ do_cache = do_cache; return(control_ldap_search(ldap_url, SEARCH_LDAP_DN, result, errmsg)); } int eldapauth_find(void *handle, uschar *filename, uschar *ldap_url, int length, uschar **result, uschar **errmsg, BOOL *do_cache) { /* Keep picky compilers happy */ do_cache = do_cache; return(control_ldap_search(ldap_url, SEARCH_LDAP_AUTH, result, errmsg)); } /************************************************* * Open entry point * *************************************************/ /* See local README for interface description. */ void * eldap_open(uschar *filename, uschar **errmsg) { return (void *)(1); /* Just return something non-null */ } /************************************************* * Tidy entry point * *************************************************/ /* See local README for interface description. Make sure that eldap_dn does not refer to reclaimed or worse, freed store */ void eldap_tidy(void) { LDAP_CONNECTION *lcp = NULL; eldap_dn = NULL; while ((lcp = ldap_connections) != NULL) { DEBUG(D_lookup) debug_printf("unbind LDAP connection to %s:%d\n", lcp->host, lcp->port); ldap_unbind(lcp->ld); ldap_connections = lcp->next; } } /************************************************* * Quote entry point * *************************************************/ /* LDAP quoting is unbelievably messy. For a start, two different levels of quoting have to be done: LDAP quoting, and URL quoting. The current specification is the result of a suggestion by Brian Candler. It recognizes two separate cases: (1) For text that appears in a search filter, the following escapes are required (see RFC 2254): * -> \2A ( -> \28 ) -> \29 \ -> \5C NULL -> \00 Then the entire filter text must be URL-escaped. This kind of quoting is implemented by ${quote_ldap:....}. Note that we can never have a NULL in the input string, because that's a terminator. (2) For a DN that is part of a URL (i.e. the base DN), the characters , + " \ < > ; must be quoted by backslashing. See RFC 2253. Leading and trailing spaces must be escaped, as must a leading #. Then the string must be URL-quoted. This type of quoting is implemented by ${quote_ldap_dn:....}. For URL quoting, the only characters that need not be quoted are the alphamerics and ! $ ' ( ) * + - . _ All the others must be hexified and preceded by %. This includes the backslashes used for LDAP quoting. For a DN that is given in the USER parameter for authentication, we need the same initial quoting as (2) but in this case, the result must NOT be URL-escaped, because it isn't a URL. The way this is handled is by de-URL-quoting the text when processing the USER parameter in control_ldap_search() above. That means that the same quote operator can be used. This has the additional advantage that spaces in the DN won't cause parsing problems. For example: USER=cn=${quote_ldap_dn:$1},%20dc=example,%20dc=com should be safe if there are spaces in $1. Arguments: s the string to be quoted opt additional option text or NULL if none only "dn" is recognized Returns: the processed string or NULL for a bad option */ /* The characters in this string, together with alphanumerics, never need quoting in any way. */ #define ALWAYS_LITERAL "!$'-._" /* The special characters in this string do not need to be URL-quoted. The set is a bit larger than the general literals. */ #define URL_NONQUOTE ALWAYS_LITERAL "()*+" /* The following macros define the characters that are quoted by quote_ldap and quote_ldap_dn, respectively. */ #define LDAP_QUOTE "*()\\" #define LDAP_DN_QUOTE ",+\"\\<>;" uschar * eldap_quote(uschar *s, uschar *opt) { register int c; int count = 0; int len = 0; BOOL dn = FALSE; uschar *t = s; uschar *quoted; /* Test for a DN quotation. */ if (opt != NULL) { if (Ustrcmp(opt, "dn") != 0) return NULL; /* No others recognized */ dn = TRUE; } /* Compute how much extra store we need for the string. This doesn't have to be exact as long as it isn't an underestimate. The worst case is the addition of 5 extra bytes for a single character. This occurs for certain characters in DNs, where, for example, < turns into %5C%3C. For simplicity, we just add 5 for each possibly escaped character. The really fast way would be just to test for non-alphanumerics, but it is probably better to spot a few others that are never escaped, because if there are no specials at all, we can avoid copying the string. */ while ((c = *t++) != 0) { len++; if (!isalnum(c) && Ustrchr(ALWAYS_LITERAL, c) == NULL) count += 5; } if (count == 0) return s; /* Get sufficient store to hold the quoted string */ t = quoted = store_get(len + count + 1); /* Handle plain quote_ldap */ if (!dn) { while ((c = *s++) != 0) { if (!isalnum(c)) { if (Ustrchr(LDAP_QUOTE, c) != NULL) { sprintf(CS t, "%%5C%02X", c); /* e.g. * => %5C2A */ t += 5; continue; } if (Ustrchr(URL_NONQUOTE, c) == NULL) /* e.g. ] => %5D */ { sprintf(CS t, "%%%02X", c); t += 3; continue; } } *t++ = c; /* unquoted character */ } } /* Handle quote_ldap_dn */ else { uschar *ss = s + len; /* Find the last char before any trailing spaces */ while (ss > s && ss[-1] == ' ') ss--; /* Quote leading spaces and sharps */ for (; s < ss; s++) { if (*s != ' ' && *s != '#') break; sprintf(CS t, "%%5C%%%02X", *s); t += 6; } /* Handle the rest of the string, up to the trailing spaces */ while (s < ss) { c = *s++; if (!isalnum(c)) { if (Ustrchr(LDAP_DN_QUOTE, c) != NULL) { Ustrncpy(t, "%5C", 3); /* insert \ where needed */ t += 3; /* fall through to check URL */ } if (Ustrchr(URL_NONQUOTE, c) == NULL) /* e.g. ] => %5D */ { sprintf(CS t, "%%%02X", c); t += 3; continue; } } *t++ = c; /* unquoted character, or non-URL quoted after %5C */ } /* Handle the trailing spaces */ while (*ss++ != 0) { Ustrncpy(t, "%5C%20", 6); t += 6; } } /* Terminate the new string and return */ *t = 0; return quoted; } #endif /* LOOKUP_LDAP */ /* End of lookups/ldap.c */