1 /* $Cambridge: exim/src/src/verify.c,v 1.24 2005/08/01 13:20:28 ph10 Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2005 */
8 /* See the file NOTICE for conditions of use and distribution. */
10 /* Functions concerned with verifying things. The original code for callout
11 caching was contributed by Kevin Fleming (but I hacked it around a bit). */
17 /* Structure for caching DNSBL lookups */
19 typedef struct dnsbl_cache_block {
27 /* Anchor for DNSBL cache */
29 static tree_node *dnsbl_cache = NULL;
33 /*************************************************
34 * Retrieve a callout cache record *
35 *************************************************/
37 /* If a record exists, check whether it has expired.
40 dbm_file an open hints file
42 type "address" or "domain"
43 positive_expire expire time for positive records
44 negative_expire expire time for negative records
46 Returns: the cache record if a non-expired one exists, else NULL
49 static dbdata_callout_cache *
50 get_callout_cache_record(open_db *dbm_file, uschar *key, uschar *type,
51 int positive_expire, int negative_expire)
56 dbdata_callout_cache *cache_record;
58 cache_record = dbfn_read_with_length(dbm_file, key, &length);
60 if (cache_record == NULL)
62 HDEBUG(D_verify) debug_printf("callout cache: no %s record found\n", type);
66 /* We treat a record as "negative" if its result field is not positive, or if
67 it is a domain record and the postmaster field is negative. */
69 negative = cache_record->result != ccache_accept ||
70 (type[0] == 'd' && cache_record->postmaster_result == ccache_reject);
71 expire = negative? negative_expire : positive_expire;
74 if (now - cache_record->time_stamp > expire)
76 HDEBUG(D_verify) debug_printf("callout cache: %s record expired\n", type);
80 /* If this is a non-reject domain record, check for the obsolete format version
81 that doesn't have the postmaster and random timestamps, by looking at the
82 length. If so, copy it to a new-style block, replicating the record's
83 timestamp. Then check the additional timestamps. (There's no point wasting
84 effort if connections are rejected.) */
86 if (type[0] == 'd' && cache_record->result != ccache_reject)
88 if (length == sizeof(dbdata_callout_cache_obs))
90 dbdata_callout_cache *new = store_get(sizeof(dbdata_callout_cache));
91 memcpy(new, cache_record, length);
92 new->postmaster_stamp = new->random_stamp = new->time_stamp;
96 if (now - cache_record->postmaster_stamp > expire)
97 cache_record->postmaster_result = ccache_unknown;
99 if (now - cache_record->random_stamp > expire)
100 cache_record->random_result = ccache_unknown;
103 HDEBUG(D_verify) debug_printf("callout cache: found %s record\n", type);
109 /*************************************************
110 * Do callout verification for an address *
111 *************************************************/
113 /* This function is called from verify_address() when the address has routed to
114 a host list, and a callout has been requested. Callouts are expensive; that is
115 why a cache is used to improve the efficiency.
118 addr the address that's been routed
119 host_list the list of hosts to try
120 tf the transport feedback block
122 ifstring "interface" option from transport, or NULL
123 portstring "port" option from transport, or NULL
124 protocolstring "protocol" option from transport, or NULL
125 callout the per-command callout timeout
126 callout_overall the overall callout timeout (if < 0 use 4*callout)
127 callout_connect the callout connection timeout (if < 0 use callout)
128 options the verification options - these bits are used:
129 vopt_is_recipient => this is a recipient address
130 vopt_callout_no_cache => don't use callout cache
131 vopt_callout_fullpm => if postmaster check, do full one
132 vopt_callout_random => do the "random" thing
133 vopt_callout_recipsender => use real sender for recipient
134 vopt_callout_recippmaster => use postmaster for recipient
135 se_mailfrom MAIL FROM address for sender verify; NULL => ""
136 pm_mailfrom if non-NULL, do the postmaster check with this sender
138 Returns: OK/FAIL/DEFER
142 do_callout(address_item *addr, host_item *host_list, transport_feedback *tf,
143 int callout, int callout_overall, int callout_connect, int options,
144 uschar *se_mailfrom, uschar *pm_mailfrom)
146 BOOL is_recipient = (options & vopt_is_recipient) != 0;
147 BOOL callout_no_cache = (options & vopt_callout_no_cache) != 0;
148 BOOL callout_random = (options & vopt_callout_random) != 0;
153 uschar *from_address;
154 uschar *random_local_part = NULL;
155 uschar **failure_ptr = is_recipient?
156 &recipient_verify_failure : &sender_verify_failure;
158 open_db *dbm_file = NULL;
159 dbdata_callout_cache new_domain_record;
160 dbdata_callout_cache_address new_address_record;
162 time_t callout_start_time;
164 new_domain_record.result = ccache_unknown;
165 new_domain_record.postmaster_result = ccache_unknown;
166 new_domain_record.random_result = ccache_unknown;
168 memset(&new_address_record, 0, sizeof(new_address_record));
170 /* For a recipient callout, the key used for the address cache record must
171 include the sender address if we are using the real sender in the callout,
172 because that may influence the result of the callout. */
174 address_key = addr->address;
179 if ((options & vopt_callout_recipsender) != 0)
181 address_key = string_sprintf("%s/<%s>", addr->address, sender_address);
182 from_address = sender_address;
184 else if ((options & vopt_callout_recippmaster) != 0)
186 address_key = string_sprintf("%s/<postmaster@%s>", addr->address,
187 qualify_domain_sender);
188 from_address = string_sprintf("postmaster@%s", qualify_domain_sender);
192 /* For a sender callout, we must adjust the key if the mailfrom address is not
197 from_address = (se_mailfrom == NULL)? US"" : se_mailfrom;
198 if (from_address[0] != 0)
199 address_key = string_sprintf("%s/<%s>", addr->address, from_address);
202 /* Open the callout cache database, it it exists, for reading only at this
203 stage, unless caching has been disabled. */
205 if (callout_no_cache)
207 HDEBUG(D_verify) debug_printf("callout cache: disabled by no_cache\n");
209 else if ((dbm_file = dbfn_open(US"callout", O_RDWR, &dbblock, FALSE)) == NULL)
211 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
214 /* If a cache database is available see if we can avoid the need to do an
215 actual callout by making use of previously-obtained data. */
217 if (dbm_file != NULL)
219 dbdata_callout_cache_address *cache_address_record;
220 dbdata_callout_cache *cache_record = get_callout_cache_record(dbm_file,
221 addr->domain, US"domain",
222 callout_cache_domain_positive_expire,
223 callout_cache_domain_negative_expire);
225 /* If an unexpired cache record was found for this domain, see if the callout
226 process can be short-circuited. */
228 if (cache_record != NULL)
230 /* If an early command (up to and including MAIL FROM:<>) was rejected,
231 there is no point carrying on. The callout fails. */
233 if (cache_record->result == ccache_reject)
235 setflag(addr, af_verify_nsfail);
237 debug_printf("callout cache: domain gave initial rejection, or "
238 "does not accept HELO or MAIL FROM:<>\n");
239 setflag(addr, af_verify_nsfail);
240 addr->user_message = US"(result of an earlier callout reused).";
242 *failure_ptr = US"mail";
246 /* If a previous check on a "random" local part was accepted, we assume
247 that the server does not do any checking on local parts. There is therefore
248 no point in doing the callout, because it will always be successful. If a
249 random check previously failed, arrange not to do it again, but preserve
250 the data in the new record. If a random check is required but hasn't been
251 done, skip the remaining cache processing. */
253 if (callout_random) switch(cache_record->random_result)
257 debug_printf("callout cache: domain accepts random addresses\n");
258 goto END_CALLOUT; /* Default yield is OK */
262 debug_printf("callout cache: domain rejects random addresses\n");
263 callout_random = FALSE;
264 new_domain_record.random_result = ccache_reject;
265 new_domain_record.random_stamp = cache_record->random_stamp;
270 debug_printf("callout cache: need to check random address handling "
271 "(not cached or cache expired)\n");
275 /* If a postmaster check is requested, but there was a previous failure,
276 there is again no point in carrying on. If a postmaster check is required,
277 but has not been done before, we are going to have to do a callout, so skip
278 remaining cache processing. */
280 if (pm_mailfrom != NULL)
282 if (cache_record->postmaster_result == ccache_reject)
284 setflag(addr, af_verify_pmfail);
286 debug_printf("callout cache: domain does not accept "
287 "RCPT TO:<postmaster@domain>\n");
289 *failure_ptr = US"postmaster";
290 setflag(addr, af_verify_pmfail);
291 addr->user_message = US"(result of earlier verification reused).";
294 if (cache_record->postmaster_result == ccache_unknown)
297 debug_printf("callout cache: need to check RCPT "
298 "TO:<postmaster@domain> (not cached or cache expired)\n");
302 /* If cache says OK, set pm_mailfrom NULL to prevent a redundant
303 postmaster check if the address itself has to be checked. Also ensure
304 that the value in the cache record is preserved (with its old timestamp).
307 HDEBUG(D_verify) debug_printf("callout cache: domain accepts RCPT "
308 "TO:<postmaster@domain>\n");
310 new_domain_record.postmaster_result = ccache_accept;
311 new_domain_record.postmaster_stamp = cache_record->postmaster_stamp;
315 /* We can't give a result based on information about the domain. See if there
316 is an unexpired cache record for this specific address (combined with the
317 sender address if we are doing a recipient callout with a non-empty sender).
320 cache_address_record = (dbdata_callout_cache_address *)
321 get_callout_cache_record(dbm_file,
322 address_key, US"address",
323 callout_cache_positive_expire,
324 callout_cache_negative_expire);
326 if (cache_address_record != NULL)
328 if (cache_address_record->result == ccache_accept)
331 debug_printf("callout cache: address record is positive\n");
336 debug_printf("callout cache: address record is negative\n");
337 addr->user_message = US"Previous (cached) callout verification failure";
338 *failure_ptr = US"recipient";
344 /* Close the cache database while we actually do the callout for real. */
347 dbfn_close(dbm_file);
351 /* The information wasn't available in the cache, so we have to do a real
352 callout and save the result in the cache for next time, unless no_cache is set,
353 or unless we have a previously cached negative random result. If we are to test
354 with a random local part, ensure that such a local part is available. If not,
355 log the fact, but carry on without randomming. */
357 if (callout_random && callout_random_local_part != NULL)
359 random_local_part = expand_string(callout_random_local_part);
360 if (random_local_part == NULL)
361 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand "
362 "callout_random_local_part: %s", expand_string_message);
365 /* Default the connect and overall callout timeouts if not set, and record the
366 time we are starting so that we can enforce it. */
368 if (callout_overall < 0) callout_overall = 4 * callout;
369 if (callout_connect < 0) callout_connect = callout;
370 callout_start_time = time(NULL);
372 /* Now make connections to the hosts and do real callouts. The list of hosts
373 is passed in as an argument. */
375 for (host = host_list; host != NULL && !done; host = host->next)
377 smtp_inblock inblock;
378 smtp_outblock outblock;
381 BOOL send_quit = TRUE;
382 uschar *helo = US"HELO";
383 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
384 uschar inbuffer[4096];
385 uschar outbuffer[1024];
386 uschar responsebuffer[4096];
388 clearflag(addr, af_verify_pmfail); /* postmaster callout flag */
389 clearflag(addr, af_verify_nsfail); /* null sender callout flag */
391 /* Skip this host if we don't have an IP address for it. */
393 if (host->address == NULL)
395 DEBUG(D_verify) debug_printf("no IP address for host name %s: skipping\n",
400 /* Check the overall callout timeout */
402 if (time(NULL) - callout_start_time >= callout_overall)
404 HDEBUG(D_verify) debug_printf("overall timeout for callout exceeded\n");
408 /* Set IPv4 or IPv6 */
410 host_af = (Ustrchr(host->address, ':') == NULL)? AF_INET:AF_INET6;
412 /* Expand and interpret the interface and port strings. This has to
413 be delayed till now, because they may expand differently for different
414 hosts. If there's a failure, log it, but carry on with the defaults. */
416 deliver_host = host->name;
417 deliver_host_address = host->address;
418 if (!smtp_get_interface(tf->interface, host_af, addr, NULL, &interface,
420 !smtp_get_port(tf->port, addr, &port, US"callout"))
421 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
423 deliver_host = deliver_host_address = NULL;
425 /* Set HELO string according to the protocol */
427 if (Ustrcmp(tf->protocol, "lmtp") == 0) helo = US"LHLO";
429 HDEBUG(D_verify) debug_printf("interface=%s port=%d\n", interface, port);
431 /* Set up the buffer for reading SMTP response packets. */
433 inblock.buffer = inbuffer;
434 inblock.buffersize = sizeof(inbuffer);
435 inblock.ptr = inbuffer;
436 inblock.ptrend = inbuffer;
438 /* Set up the buffer for holding SMTP commands while pipelining */
440 outblock.buffer = outbuffer;
441 outblock.buffersize = sizeof(outbuffer);
442 outblock.ptr = outbuffer;
443 outblock.cmd_count = 0;
444 outblock.authenticating = FALSE;
446 /* Connect to the host; on failure, just loop for the next one, but we
447 set the error for the last one. Use the callout_connect timeout. */
449 inblock.sock = outblock.sock =
450 smtp_connect(host, host_af, port, interface, callout_connect, TRUE);
451 if (inblock.sock < 0)
453 addr->message = string_sprintf("could not connect to %s [%s]: %s",
454 host->name, host->address, strerror(errno));
458 /* Wait for initial response, and then run the initial SMTP commands. The
459 smtp_write_command() function leaves its command in big_buffer. This is
460 used in error responses. Initialize it in case the connection is
463 Ustrcpy(big_buffer, "initial connection");
466 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
469 smtp_write_command(&outblock, FALSE, "%s %s\r\n", helo,
470 smtp_active_hostname) >= 0 &&
471 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
474 smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>\r\n",
475 from_address) >= 0 &&
476 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
479 /* If the host gave an initial error, or does not accept HELO or MAIL
480 FROM:<>, arrange to cache this information, but don't record anything for an
481 I/O error or a defer. Do not cache rejections when a non-empty sender has
482 been used, because that blocks the whole domain for all senders. */
486 *failure_ptr = US"mail";
487 if (errno == 0 && responsebuffer[0] == '5')
489 setflag(addr, af_verify_nsfail);
490 if (from_address[0] == 0) new_domain_record.result = ccache_reject;
494 /* Otherwise, proceed to check a "random" address (if required), then the
495 given address, and the postmaster address (if required). Between each check,
496 issue RSET, because some servers accept only one recipient after MAIL
501 new_domain_record.result = ccache_accept;
503 /* Do the random local part check first */
505 if (random_local_part != NULL)
507 uschar randombuffer[1024];
509 smtp_write_command(&outblock, FALSE,
510 "RCPT TO:<%.1000s@%.1000s>\r\n", random_local_part,
511 addr->domain) >= 0 &&
512 smtp_read_response(&inblock, randombuffer,
513 sizeof(randombuffer), '2', callout);
515 /* Remember when we last did a random test */
517 new_domain_record.random_stamp = time(NULL);
519 /* If accepted, we aren't going to do any further tests below. */
523 new_domain_record.random_result = ccache_accept;
526 /* Otherwise, cache a real negative response, and get back to the right
527 state to send RCPT. Unless there's some problem such as a dropped
528 connection, we expect to succeed, because the commands succeeded above. */
532 if (randombuffer[0] == '5')
533 new_domain_record.random_result = ccache_reject;
536 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
537 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
540 smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>\r\n",
541 from_address) >= 0 &&
542 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
545 else done = FALSE; /* Some timeout/connection problem */
548 /* If the host is accepting all local parts, as determined by the "random"
549 check, we don't need to waste time doing any further checking. */
551 if (new_domain_record.random_result != ccache_accept && done)
553 /* Get the rcpt_include_affixes flag from the transport if there is one,
554 but assume FALSE if there is not. */
557 smtp_write_command(&outblock, FALSE, "RCPT TO:<%.1000s>\r\n",
558 transport_rcpt_address(addr,
559 (addr->transport == NULL)? FALSE :
560 addr->transport->rcpt_include_affixes)) >= 0 &&
561 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
565 new_address_record.result = ccache_accept;
566 else if (errno == 0 && responsebuffer[0] == '5')
568 *failure_ptr = US"recipient";
569 new_address_record.result = ccache_reject;
572 /* Do postmaster check if requested; if a full check is required, we
573 check for RCPT TO:<postmaster> (no domain) in accordance with RFC 821. */
575 if (done && pm_mailfrom != NULL)
578 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
579 smtp_read_response(&inblock, responsebuffer,
580 sizeof(responsebuffer), '2', callout) &&
582 smtp_write_command(&outblock, FALSE,
583 "MAIL FROM:<%s>\r\n", pm_mailfrom) >= 0 &&
584 smtp_read_response(&inblock, responsebuffer,
585 sizeof(responsebuffer), '2', callout) &&
587 /* First try using the current domain */
590 smtp_write_command(&outblock, FALSE,
591 "RCPT TO:<postmaster@%.1000s>\r\n", addr->domain) >= 0 &&
592 smtp_read_response(&inblock, responsebuffer,
593 sizeof(responsebuffer), '2', callout)
598 /* If that doesn't work, and a full check is requested,
599 try without the domain. */
602 (options & vopt_callout_fullpm) != 0 &&
603 smtp_write_command(&outblock, FALSE,
604 "RCPT TO:<postmaster>\r\n") >= 0 &&
605 smtp_read_response(&inblock, responsebuffer,
606 sizeof(responsebuffer), '2', callout)
609 /* Sort out the cache record */
611 new_domain_record.postmaster_stamp = time(NULL);
614 new_domain_record.postmaster_result = ccache_accept;
615 else if (errno == 0 && responsebuffer[0] == '5')
617 *failure_ptr = US"postmaster";
618 setflag(addr, af_verify_pmfail);
619 new_domain_record.postmaster_result = ccache_reject;
622 } /* Random not accepted */
623 } /* MAIL FROM: accepted */
625 /* For any failure of the main check, other than a negative response, we just
626 close the connection and carry on. We can identify a negative response by the
627 fact that errno is zero. For I/O errors it will be non-zero
629 Set up different error texts for logging and for sending back to the caller
630 as an SMTP response. Log in all cases, using a one-line format. For sender
631 callouts, give a full response to the caller, but for recipient callouts,
632 don't give the IP address because this may be an internal host whose identity
633 is not to be widely broadcast. */
637 if (errno == ETIMEDOUT)
639 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
644 if (*responsebuffer == 0) Ustrcpy(responsebuffer, US"connection dropped");
647 string_sprintf("response to \"%s\" from %s [%s] was: %s",
648 big_buffer, host->name, host->address,
649 string_printing(responsebuffer));
651 addr->user_message = is_recipient?
652 string_sprintf("Callout verification failed:\n%s", responsebuffer)
654 string_sprintf("Called: %s\nSent: %s\nResponse: %s",
655 host->address, big_buffer, responsebuffer);
657 /* Hard rejection ends the process */
659 if (responsebuffer[0] == '5') /* Address rejected */
667 /* End the SMTP conversation and close the connection. */
669 if (send_quit) (void)smtp_write_command(&outblock, FALSE, "QUIT\r\n");
670 (void)close(inblock.sock);
671 } /* Loop through all hosts, while !done */
673 /* If we get here with done == TRUE, a successful callout happened, and yield
674 will be set OK or FAIL according to the response to the RCPT command.
675 Otherwise, we looped through the hosts but couldn't complete the business.
676 However, there may be domain-specific information to cache in both cases.
678 The value of the result field in the new_domain record is ccache_unknown if
679 there was an error before or with MAIL FROM:, and errno was not zero,
680 implying some kind of I/O error. We don't want to write the cache in that case.
681 Otherwise the value is ccache_accept or ccache_reject. */
683 if (!callout_no_cache && new_domain_record.result != ccache_unknown)
685 if ((dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE))
688 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
692 (void)dbfn_write(dbm_file, addr->domain, &new_domain_record,
693 (int)sizeof(dbdata_callout_cache));
694 HDEBUG(D_verify) debug_printf("wrote callout cache domain record:\n"
695 " result=%d postmaster=%d random=%d\n",
696 new_domain_record.result,
697 new_domain_record.postmaster_result,
698 new_domain_record.random_result);
702 /* If a definite result was obtained for the callout, cache it unless caching
707 if (!callout_no_cache && new_address_record.result != ccache_unknown)
709 if (dbm_file == NULL)
710 dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE);
711 if (dbm_file == NULL)
713 HDEBUG(D_verify) debug_printf("no callout cache available\n");
717 (void)dbfn_write(dbm_file, address_key, &new_address_record,
718 (int)sizeof(dbdata_callout_cache_address));
719 HDEBUG(D_verify) debug_printf("wrote %s callout cache address record\n",
720 (new_address_record.result == ccache_accept)? "positive" : "negative");
725 /* Failure to connect to any host, or any response other than 2xx or 5xx is a
726 temporary error. If there was only one host, and a response was received, leave
727 it alone if supplying details. Otherwise, give a generic response. */
731 uschar *dullmsg = string_sprintf("Could not complete %s verify callout",
732 is_recipient? "recipient" : "sender");
735 if (host_list->next != NULL || addr->message == NULL) addr->message = dullmsg;
737 addr->user_message = (!smtp_return_error_details)? dullmsg :
738 string_sprintf("%s for <%s>.\n"
739 "The mail server(s) for the domain may be temporarily unreachable, or\n"
740 "they may be permanently unreachable from this server. In the latter case,\n%s",
741 dullmsg, addr->address,
743 "the address will never be accepted."
745 "you need to change the address or create an MX record for its domain\n"
746 "if it is supposed to be generally accessible from the Internet.\n"
747 "Talk to your mail administrator for details.");
749 /* Force a specific error code */
751 addr->basic_errno = ERRNO_CALLOUTDEFER;
754 /* Come here from within the cache-reading code on fast-track exit. */
757 if (dbm_file != NULL) dbfn_close(dbm_file);
763 /*************************************************
764 * Copy error to toplevel address *
765 *************************************************/
767 /* This function is used when a verify fails or defers, to ensure that the
768 failure or defer information is in the original toplevel address. This applies
769 when an address is redirected to a single new address, and the failure or
770 deferral happens to the child address.
773 vaddr the verify address item
774 addr the final address item
777 Returns: the value of YIELD
781 copy_error(address_item *vaddr, address_item *addr, int yield)
785 vaddr->message = addr->message;
786 vaddr->user_message = addr->user_message;
787 vaddr->basic_errno = addr->basic_errno;
788 vaddr->more_errno = addr->more_errno;
796 /*************************************************
797 * Verify an email address *
798 *************************************************/
800 /* This function is used both for verification (-bv and at other times) and
801 address testing (-bt), which is indicated by address_test_mode being set.
804 vaddr contains the address to verify; the next field in this block
806 f if not NULL, write the result to this file
807 options various option bits:
808 vopt_fake_sender => this sender verify is not for the real
809 sender (it was verify=sender=xxxx or an address from a
810 header line) - rewriting must not change sender_address
811 vopt_is_recipient => this is a recipient address, otherwise
812 it's a sender address - this affects qualification and
813 rewriting and messages from callouts
814 vopt_qualify => qualify an unqualified address; else error
815 vopt_expn => called from SMTP EXPN command
816 vopt_success_on_redirect => when a new address is generated
817 the verification instantly succeeds
819 These ones are used by do_callout() -- the options variable
822 vopt_callout_fullpm => if postmaster check, do full one
823 vopt_callout_no_cache => don't use callout cache
824 vopt_callout_random => do the "random" thing
825 vopt_callout_recipsender => use real sender for recipient
826 vopt_callout_recippmaster => use postmaster for recipient
828 callout if > 0, specifies that callout is required, and gives timeout
829 for individual commands
830 callout_overall if > 0, gives overall timeout for the callout function;
831 if < 0, a default is used (see do_callout())
832 callout_connect the connection timeout for callouts
833 se_mailfrom when callout is requested to verify a sender, use this
834 in MAIL FROM; NULL => ""
835 pm_mailfrom when callout is requested, if non-NULL, do the postmaster
836 thing and use this as the sender address (may be "")
838 routed if not NULL, set TRUE if routing succeeded, so we can
839 distinguish between routing failed and callout failed
841 Returns: OK address verified
842 FAIL address failed to verify
843 DEFER can't tell at present
847 verify_address(address_item *vaddr, FILE *f, int options, int callout,
848 int callout_overall, int callout_connect, uschar *se_mailfrom,
849 uschar *pm_mailfrom, BOOL *routed)
852 BOOL full_info = (f == NULL)? FALSE : (debug_selector != 0);
853 BOOL is_recipient = (options & vopt_is_recipient) != 0;
854 BOOL expn = (options & vopt_expn) != 0;
855 BOOL success_on_redirect = (options & vopt_success_on_redirect) != 0;
858 int verify_type = expn? v_expn :
859 address_test_mode? v_none :
860 is_recipient? v_recipient : v_sender;
861 address_item *addr_list;
862 address_item *addr_new = NULL;
863 address_item *addr_remote = NULL;
864 address_item *addr_local = NULL;
865 address_item *addr_succeed = NULL;
866 uschar **failure_ptr = is_recipient?
867 &recipient_verify_failure : &sender_verify_failure;
868 uschar *ko_prefix, *cr;
869 uschar *address = vaddr->address;
871 uschar null_sender[] = { 0 }; /* Ensure writeable memory */
873 /* Clear, just in case */
877 /* Set up a prefix and suffix for error message which allow us to use the same
878 output statements both in EXPN mode (where an SMTP response is needed) and when
879 debugging with an output file. */
883 ko_prefix = US"553 ";
886 else ko_prefix = cr = US"";
888 /* Add qualify domain if permitted; otherwise an unqualified address fails. */
890 if (parse_find_at(address) == NULL)
892 if ((options & vopt_qualify) == 0)
895 fprintf(f, "%sA domain is required for \"%s\"%s\n", ko_prefix, address,
897 *failure_ptr = US"qualify";
900 address = rewrite_address_qualify(address, is_recipient);
905 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
906 debug_printf("%s %s\n", address_test_mode? "Testing" : "Verifying", address);
909 /* Rewrite and report on it. Clear the domain and local part caches - these
910 may have been set by domains and local part tests during an ACL. */
912 if (global_rewrite_rules != NULL)
914 uschar *old = address;
915 address = rewrite_address(address, is_recipient, FALSE,
916 global_rewrite_rules, rewrite_existflags);
919 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->localpart_cache[i] = 0;
920 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->domain_cache[i] = 0;
921 if (f != NULL && !expn) fprintf(f, "Address rewritten as: %s\n", address);
925 /* If this is the real sender address, we must update sender_address at
926 this point, because it may be referred to in the routers. */
928 if ((options & (vopt_fake_sender|vopt_is_recipient)) == 0)
929 sender_address = address;
931 /* If the address was rewritten to <> no verification can be done, and we have
932 to return OK. This rewriting is permitted only for sender addresses; for other
933 addresses, such rewriting fails. */
935 if (address[0] == 0) return OK;
937 /* Save a copy of the sender address for re-instating if we change it to <>
938 while verifying a sender address (a nice bit of self-reference there). */
940 save_sender = sender_address;
942 /* Update the address structure with the possibly qualified and rewritten
943 address. Set it up as the starting address on the chain of new addresses. */
945 vaddr->address = address;
948 /* We need a loop, because an address can generate new addresses. We must also
949 cope with generated pipes and files at the top level. (See also the code and
950 comment in deliver.c.) However, it is usually the case that the router for
951 user's .forward files has its verify flag turned off.
953 If an address generates more than one child, the loop is used only when
954 full_info is set, and this can only be set locally. Remote enquiries just get
955 information about the top level address, not anything that it generated. */
957 while (addr_new != NULL)
960 address_item *addr = addr_new;
962 addr_new = addr->next;
967 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
968 debug_printf("Considering %s\n", addr->address);
971 /* Handle generated pipe, file or reply addresses. We don't get these
972 when handling EXPN, as it does only one level of expansion. */
974 if (testflag(addr, af_pfr))
981 if (addr->address[0] == '>')
983 allow = testflag(addr, af_allow_reply);
984 fprintf(f, "%s -> mail %s", addr->parent->address, addr->address + 1);
988 allow = (addr->address[0] == '|')?
989 testflag(addr, af_allow_pipe) : testflag(addr, af_allow_file);
990 fprintf(f, "%s -> %s", addr->parent->address, addr->address);
993 if (addr->basic_errno == ERRNO_BADTRANSPORT)
994 fprintf(f, "\n*** Error in setting up pipe, file, or autoreply:\n"
995 "%s\n", addr->message);
997 fprintf(f, "\n transport = %s\n", addr->transport->name);
999 fprintf(f, " *** forbidden ***\n");
1004 /* Just in case some router parameter refers to it. */
1006 return_path = (addr->p.errors_address != NULL)?
1007 addr->p.errors_address : sender_address;
1009 /* Split the address into domain and local part, handling the %-hack if
1010 necessary, and then route it. While routing a sender address, set
1011 $sender_address to <> because that is what it will be if we were trying to
1012 send a bounce to the sender. */
1014 if (routed != NULL) *routed = FALSE;
1015 if ((rc = deliver_split_address(addr)) == OK)
1017 if (!is_recipient) sender_address = null_sender;
1018 rc = route_address(addr, &addr_local, &addr_remote, &addr_new,
1019 &addr_succeed, verify_type);
1020 sender_address = save_sender; /* Put back the real sender */
1023 /* If routing an address succeeded, set the flag that remembers, for use when
1024 an ACL cached a sender verify (in case a callout fails). Then if routing set
1025 up a list of hosts or the transport has a host list, and the callout option
1026 is set, and we aren't in a host checking run, do the callout verification,
1027 and set another flag that notes that a callout happened. */
1031 if (routed != NULL) *routed = TRUE;
1034 host_item *host_list = addr->host_list;
1036 /* Default, if no remote transport, to NULL for the interface (=> any),
1037 "smtp" for the port, and "smtp" for the protocol. */
1039 transport_feedback tf = { NULL, US"smtp", US"smtp", NULL, FALSE, FALSE };
1041 /* If verification yielded a remote transport, we want to use that
1042 transport's options, so as to mimic what would happen if we were really
1043 sending a message to this address. */
1045 if (addr->transport != NULL && !addr->transport->info->local)
1047 (void)(addr->transport->setup)(addr->transport, addr, &tf, NULL);
1049 /* If the transport has hosts and the router does not, or if the
1050 transport is configured to override the router's hosts, we must build a
1051 host list of the transport's hosts, and find the IP addresses */
1053 if (tf.hosts != NULL && (host_list == NULL || tf.hosts_override))
1057 host_list = NULL; /* Ignore the router's hosts */
1059 deliver_domain = addr->domain;
1060 deliver_localpart = addr->local_part;
1061 s = expand_string(tf.hosts);
1062 deliver_domain = deliver_localpart = NULL;
1066 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand list of hosts "
1067 "\"%s\" in %s transport for callout: %s", tf.hosts,
1068 addr->transport->name, expand_string_message);
1072 uschar *canonical_name;
1073 host_item *host, *nexthost;
1074 host_build_hostlist(&host_list, s, tf.hosts_randomize);
1076 /* Just ignore failures to find a host address. If we don't manage
1077 to find any addresses, the callout will defer. Note that more than
1078 one address may be found for a single host, which will result in
1079 additional host items being inserted into the chain. Hence we must
1080 save the next host first. */
1082 for (host = host_list; host != NULL; host = nexthost)
1084 nexthost = host->next;
1085 if (tf.gethostbyname ||
1086 string_is_ip_address(host->name, NULL) > 0)
1087 (void)host_find_byname(host, NULL, &canonical_name, TRUE);
1090 int flags = HOST_FIND_BY_A;
1091 if (tf.qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
1092 if (tf.search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
1093 (void)host_find_bydns(host, NULL, flags, NULL, NULL, NULL,
1094 &canonical_name, NULL);
1101 /* Can only do a callout if we have at least one host! If the callout
1102 fails, it will have set ${sender,recipient}_verify_failure. */
1104 if (host_list != NULL)
1106 HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n");
1107 if (host_checking && !host_checking_callout)
1110 debug_printf("... callout omitted by default when host testing\n"
1111 "(Use -bhc if you want the callouts to happen.)\n");
1115 rc = do_callout(addr, host_list, &tf, callout, callout_overall,
1116 callout_connect, options, se_mailfrom, pm_mailfrom);
1121 HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor "
1122 "transport provided a host list\n");
1127 /* Otherwise, any failure is a routing failure */
1129 else *failure_ptr = US"route";
1131 /* A router may return REROUTED if it has set up a child address as a result
1132 of a change of domain name (typically from widening). In this case we always
1133 want to continue to verify the new child. */
1135 if (rc == REROUTED) continue;
1137 /* Handle hard failures */
1144 fprintf(f, "%s%s %s", ko_prefix, address,
1145 address_test_mode? "is undeliverable" : "failed to verify");
1146 if (!expn && admin_user)
1148 if (addr->basic_errno > 0)
1149 fprintf(f, ": %s", strerror(addr->basic_errno));
1150 if (addr->message != NULL)
1151 fprintf(f, ":\n %s", addr->message);
1153 fprintf(f, "%s\n", cr);
1156 if (!full_info) return copy_error(vaddr, addr, FAIL);
1162 else if (rc == DEFER)
1167 fprintf(f, "%s%s cannot be resolved at this time", ko_prefix, address);
1168 if (!expn && admin_user)
1170 if (addr->basic_errno > 0)
1171 fprintf(f, ":\n %s", strerror(addr->basic_errno));
1172 if (addr->message != NULL)
1173 fprintf(f, ":\n %s", addr->message);
1174 else if (addr->basic_errno <= 0)
1175 fprintf(f, ":\n unknown error");
1178 fprintf(f, "%s\n", cr);
1180 if (!full_info) return copy_error(vaddr, addr, DEFER);
1181 else if (yield == OK) yield = DEFER;
1184 /* If we are handling EXPN, we do not want to continue to route beyond
1189 uschar *ok_prefix = US"250-";
1190 if (addr_new == NULL)
1192 if (addr_local == NULL && addr_remote == NULL)
1193 fprintf(f, "250 mail to <%s> is discarded\r\n", address);
1195 fprintf(f, "250 <%s>\r\n", address);
1197 else while (addr_new != NULL)
1199 address_item *addr2 = addr_new;
1200 addr_new = addr2->next;
1201 if (addr_new == NULL) ok_prefix = US"250 ";
1202 fprintf(f, "%s<%s>\r\n", ok_prefix, addr2->address);
1207 /* Successful routing other than EXPN. */
1211 /* Handle successful routing when short info wanted. Otherwise continue for
1212 other (generated) addresses. Short info is the operational case. Full info
1213 can be requested only when debug_selector != 0 and a file is supplied.
1215 There is a conflict between the use of aliasing as an alternate email
1216 address, and as a sort of mailing list. If an alias turns the incoming
1217 address into just one address (e.g. J.Caesar->jc44) you may well want to
1218 carry on verifying the generated address to ensure it is valid when
1219 checking incoming mail. If aliasing generates multiple addresses, you
1220 probably don't want to do this. Exim therefore treats the generation of
1221 just a single new address as a special case, and continues on to verify the
1222 generated address. */
1224 if (!full_info && /* Stop if short info wanted AND */
1225 (((addr_new == NULL || /* No new address OR */
1226 addr_new->next != NULL || /* More than one new address OR */
1227 testflag(addr_new, af_pfr))) /* New address is pfr */
1229 (addr_new != NULL && /* At least one new address AND */
1230 success_on_redirect))) /* success_on_redirect is set */
1232 if (f != NULL) fprintf(f, "%s %s\n", address,
1233 address_test_mode? "is deliverable" : "verified");
1235 /* If we have carried on to verify a child address, we want the value
1236 of $address_data to be that of the child */
1238 vaddr->p.address_data = addr->p.address_data;
1242 } /* Loop for generated addresses */
1244 /* Display the full results of the successful routing, including any generated
1245 addresses. Control gets here only when full_info is set, which requires f not
1246 to be NULL, and this occurs only when a top-level verify is called with the
1247 debugging switch on.
1249 If there are no local and no remote addresses, and there were no pipes, files,
1250 or autoreplies, and there were no errors or deferments, the message is to be
1251 discarded, usually because of the use of :blackhole: in an alias file. */
1253 if (allok && addr_local == NULL && addr_remote == NULL)
1254 fprintf(f, "mail to %s is discarded\n", address);
1256 else for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++)
1258 while (addr_list != NULL)
1260 address_item *addr = addr_list;
1261 address_item *p = addr->parent;
1262 addr_list = addr->next;
1264 fprintf(f, "%s", CS addr->address);
1265 #ifdef EXPERIMENTAL_SRS
1266 if(addr->p.srs_sender)
1267 fprintf(f, " [srs = %s]", addr->p.srs_sender);
1271 fprintf(f, "\n <-- %s", p->address);
1276 /* Show router, and transport */
1278 fprintf(f, "router = %s, ", addr->router->name);
1279 fprintf(f, "transport = %s\n", (addr->transport == NULL)? US"unset" :
1280 addr->transport->name);
1282 /* Show any hosts that are set up by a router unless the transport
1283 is going to override them; fiddle a bit to get a nice format. */
1285 if (addr->host_list != NULL && addr->transport != NULL &&
1286 !addr->transport->overrides_hosts)
1291 for (h = addr->host_list; h != NULL; h = h->next)
1293 int len = Ustrlen(h->name);
1294 if (len > maxlen) maxlen = len;
1295 len = (h->address != NULL)? Ustrlen(h->address) : 7;
1296 if (len > maxaddlen) maxaddlen = len;
1298 for (h = addr->host_list; h != NULL; h = h->next)
1300 int len = Ustrlen(h->name);
1301 fprintf(f, " host %s ", h->name);
1302 while (len++ < maxlen) fprintf(f, " ");
1303 if (h->address != NULL)
1305 fprintf(f, "[%s] ", h->address);
1306 len = Ustrlen(h->address);
1308 else if (!addr->transport->info->local) /* Omit [unknown] for local */
1310 fprintf(f, "[unknown] ");
1314 while (len++ < maxaddlen) fprintf(f," ");
1315 if (h->mx >= 0) fprintf(f, "MX=%d", h->mx);
1316 if (h->port != PORT_NONE) fprintf(f, " port=%d", h->port);
1317 if (h->status == hstatus_unusable) fprintf(f, " ** unusable **");
1324 /* Will be DEFER or FAIL if any one address has, only for full_info (which is
1325 the -bv or -bt case). */
1333 /*************************************************
1334 * Check headers for syntax errors *
1335 *************************************************/
1337 /* This function checks those header lines that contain addresses, and verifies
1338 that all the addresses therein are syntactially correct.
1341 msgptr where to put an error message
1348 verify_check_headers(uschar **msgptr)
1353 for (h = header_list; h != NULL; h = h->next)
1355 if (h->type != htype_from &&
1356 h->type != htype_reply_to &&
1357 h->type != htype_sender &&
1358 h->type != htype_to &&
1359 h->type != htype_cc &&
1360 h->type != htype_bcc)
1363 colon = Ustrchr(h->text, ':');
1365 while (isspace(*s)) s++;
1367 parse_allow_group = TRUE; /* Allow group syntax */
1369 /* Loop for multiple addresses in the header */
1373 uschar *ss = parse_find_address_end(s, FALSE);
1374 uschar *recipient, *errmess;
1375 int terminator = *ss;
1376 int start, end, domain;
1378 /* Temporarily terminate the string at this point, and extract the
1379 operative address within. */
1382 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
1385 /* Permit an unqualified address only if the message is local, or if the
1386 sending host is configured to be permitted to send them. */
1388 if (recipient != NULL && domain == 0)
1390 if (h->type == htype_from || h->type == htype_sender)
1392 if (!allow_unqualified_sender) recipient = NULL;
1396 if (!allow_unqualified_recipient) recipient = NULL;
1398 if (recipient == NULL) errmess = US"unqualified address not permitted";
1401 /* It's an error if no address could be extracted, except for the special
1402 case of an empty address. */
1404 if (recipient == NULL && Ustrcmp(errmess, "empty address") != 0)
1406 uschar *verb = US"is";
1410 /* Arrange not to include any white space at the end in the
1413 while (t > s && isspace(t[-1])) t--;
1415 /* Add the address which failed to the error message, since in a
1416 header with very many addresses it is sometimes hard to spot
1417 which one is at fault. However, limit the amount of address to
1418 quote - cases have been seen where, for example, a missing double
1419 quote in a humungous To: header creates an "address" that is longer
1420 than string_sprintf can handle. */
1429 *msgptr = string_printing(
1430 string_sprintf("%s: failing address in \"%.*s\" header %s: %.*s",
1431 errmess, colon - h->text, h->text, verb, len, s));
1436 /* Advance to the next address */
1438 s = ss + (terminator? 1:0);
1439 while (isspace(*s)) s++;
1440 } /* Next address */
1449 /*************************************************
1450 * Find if verified sender *
1451 *************************************************/
1453 /* Usually, just a single address is verified as the sender of the message.
1454 However, Exim can be made to verify other addresses as well (often related in
1455 some way), and this is useful in some environments. There may therefore be a
1456 chain of such addresses that have previously been tested. This function finds
1457 whether a given address is on the chain.
1459 Arguments: the address to be verified
1460 Returns: pointer to an address item, or NULL
1464 verify_checked_sender(uschar *sender)
1467 for (addr = sender_verified_list; addr != NULL; addr = addr->next)
1468 if (Ustrcmp(sender, addr->address) == 0) break;
1476 /*************************************************
1477 * Get valid header address *
1478 *************************************************/
1480 /* Scan the originator headers of the message, looking for an address that
1481 verifies successfully. RFC 822 says:
1483 o The "Sender" field mailbox should be sent notices of
1484 any problems in transport or delivery of the original
1485 messages. If there is no "Sender" field, then the
1486 "From" field mailbox should be used.
1488 o If the "Reply-To" field exists, then the reply should
1489 go to the addresses indicated in that field and not to
1490 the address(es) indicated in the "From" field.
1492 So we check a Sender field if there is one, else a Reply_to field, else a From
1493 field. As some strange messages may have more than one of these fields,
1494 especially if they are resent- fields, check all of them if there is more than
1498 user_msgptr points to where to put a user error message
1499 log_msgptr points to where to put a log error message
1500 callout timeout for callout check (passed to verify_address())
1501 callout_overall overall callout timeout (ditto)
1502 callout_connect connect callout timeout (ditto)
1503 se_mailfrom mailfrom for verify; NULL => ""
1504 pm_mailfrom sender for pm callout check (passed to verify_address())
1505 options callout options (passed to verify_address())
1506 verrno where to put the address basic_errno
1508 If log_msgptr is set to something without setting user_msgptr, the caller
1509 normally uses log_msgptr for both things.
1511 Returns: result of the verification attempt: OK, FAIL, or DEFER;
1512 FAIL is given if no appropriate headers are found
1516 verify_check_header_address(uschar **user_msgptr, uschar **log_msgptr,
1517 int callout, int callout_overall, int callout_connect, uschar *se_mailfrom,
1518 uschar *pm_mailfrom, int options, int *verrno)
1520 static int header_types[] = { htype_sender, htype_reply_to, htype_from };
1524 for (i = 0; i < 3; i++)
1527 for (h = header_list; h != NULL; h = h->next)
1529 int terminator, new_ok;
1530 uschar *s, *ss, *endname;
1532 if (h->type != header_types[i]) continue;
1533 s = endname = Ustrchr(h->text, ':') + 1;
1537 address_item *vaddr;
1539 while (isspace(*s) || *s == ',') s++;
1540 if (*s == 0) break; /* End of header */
1542 ss = parse_find_address_end(s, FALSE);
1544 /* The terminator is a comma or end of header, but there may be white
1545 space preceding it (including newline for the last address). Move back
1546 past any white space so we can check against any cached envelope sender
1547 address verifications. */
1549 while (isspace(ss[-1])) ss--;
1553 HDEBUG(D_verify) debug_printf("verifying %.*s header address %s\n",
1554 (int)(endname - h->text), h->text, s);
1556 /* See if we have already verified this address as an envelope sender,
1557 and if so, use the previous answer. */
1559 vaddr = verify_checked_sender(s);
1561 if (vaddr != NULL && /* Previously checked */
1562 (callout <= 0 || /* No callout needed; OR */
1563 vaddr->special_action > 256)) /* Callout was done */
1565 new_ok = vaddr->special_action & 255;
1566 HDEBUG(D_verify) debug_printf("previously checked as envelope sender\n");
1567 *ss = terminator; /* Restore shortened string */
1570 /* Otherwise we run the verification now. We must restore the shortened
1571 string before running the verification, so the headers are correct, in
1572 case there is any rewriting. */
1576 int start, end, domain;
1577 uschar *address = parse_extract_address(s, log_msgptr, &start,
1578 &end, &domain, FALSE);
1582 /* If verification failed because of a syntax error, fail this
1583 function, and ensure that the failing address gets added to the error
1586 if (address == NULL)
1589 if (*log_msgptr != NULL)
1591 while (ss > s && isspace(ss[-1])) ss--;
1592 *log_msgptr = string_sprintf("syntax error in '%.*s' header when "
1593 "scanning for sender: %s in \"%.*s\"",
1594 endname - h->text, h->text, *log_msgptr, ss - s, s);
1599 /* Else go ahead with the sender verification. But it isn't *the*
1600 sender of the message, so set vopt_fake_sender to stop sender_address
1601 being replaced after rewriting or qualification. */
1605 vaddr = deliver_make_addr(address, FALSE);
1606 new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender,
1607 callout, callout_overall, callout_connect, se_mailfrom,
1612 /* We now have the result, either newly found, or cached. If we are
1613 giving out error details, set a specific user error. This means that the
1614 last of these will be returned to the user if all three fail. We do not
1615 set a log message - the generic one below will be used. */
1619 *verrno = vaddr->basic_errno;
1620 if (smtp_return_error_details)
1622 *user_msgptr = string_sprintf("Rejected after DATA: "
1623 "could not verify \"%.*s\" header address\n%s: %s",
1624 endname - h->text, h->text, vaddr->address, vaddr->message);
1628 /* Success or defer */
1630 if (new_ok == OK) return OK;
1631 if (new_ok == DEFER) yield = DEFER;
1633 /* Move on to any more addresses in the header */
1640 if (yield == FAIL && *log_msgptr == NULL)
1641 *log_msgptr = US"there is no valid sender in any header line";
1643 if (yield == DEFER && *log_msgptr == NULL)
1644 *log_msgptr = US"all attempts to verify a sender in a header line deferred";
1652 /*************************************************
1653 * Get RFC 1413 identification *
1654 *************************************************/
1656 /* Attempt to get an id from the sending machine via the RFC 1413 protocol. If
1657 the timeout is set to zero, then the query is not done. There may also be lists
1658 of hosts and nets which are exempt. To guard against malefactors sending
1659 non-printing characters which could, for example, disrupt a message's headers,
1660 make sure the string consists of printing characters only.
1663 port the port to connect to; usually this is IDENT_PORT (113), but when
1664 running in the test harness with -bh a different value is used.
1668 Side effect: any received ident value is put in sender_ident (NULL otherwise)
1672 verify_get_ident(int port)
1674 int sock, host_af, qlen;
1675 int received_sender_port, received_interface_port, n;
1677 uschar buffer[2048];
1679 /* Default is no ident. Check whether we want to do an ident check for this
1682 sender_ident = NULL;
1683 if (rfc1413_query_timeout <= 0 || verify_check_host(&rfc1413_hosts) != OK)
1686 DEBUG(D_ident) debug_printf("doing ident callback\n");
1688 /* Set up a connection to the ident port of the remote host. Bind the local end
1689 to the incoming interface address. If the sender host address is an IPv6
1690 address, the incoming interface address will also be IPv6. */
1692 host_af = (Ustrchr(sender_host_address, ':') == NULL)? AF_INET : AF_INET6;
1693 sock = ip_socket(SOCK_STREAM, host_af);
1694 if (sock < 0) return;
1696 if (ip_bind(sock, host_af, interface_address, 0) < 0)
1698 DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n",
1703 if (ip_connect(sock, host_af, sender_host_address, port, rfc1413_query_timeout)
1706 if (errno == ETIMEDOUT && (log_extra_selector & LX_ident_timeout) != 0)
1708 log_write(0, LOG_MAIN, "ident connection to %s timed out",
1709 sender_host_address);
1713 DEBUG(D_ident) debug_printf("ident connection to %s failed: %s\n",
1714 sender_host_address, strerror(errno));
1719 /* Construct and send the query. */
1721 sprintf(CS buffer, "%d , %d\r\n", sender_host_port, interface_port);
1722 qlen = Ustrlen(buffer);
1723 if (send(sock, buffer, qlen, 0) < 0)
1725 DEBUG(D_ident) debug_printf("ident send failed: %s\n", strerror(errno));
1729 /* Read a response line. We put it into the rest of the buffer, using several
1730 recv() calls if necessary. */
1738 int size = sizeof(buffer) - (p - buffer);
1740 if (size <= 0) goto END_OFF; /* Buffer filled without seeing \n. */
1741 count = ip_recv(sock, p, size, rfc1413_query_timeout);
1742 if (count <= 0) goto END_OFF; /* Read error or EOF */
1744 /* Scan what we just read, to see if we have reached the terminating \r\n. Be
1745 generous, and accept a plain \n terminator as well. The only illegal
1748 for (pp = p; pp < p + count; pp++)
1750 if (*pp == 0) goto END_OFF; /* Zero octet not allowed */
1753 if (pp[-1] == '\r') pp--;
1755 goto GOT_DATA; /* Break out of both loops */
1759 /* Reached the end of the data without finding \n. Let the loop continue to
1760 read some more, if there is room. */
1767 /* We have received a line of data. Check it carefully. It must start with the
1768 same two port numbers that we sent, followed by data as defined by the RFC. For
1771 12345 , 25 : USERID : UNIX :root
1773 However, the amount of white space may be different to what we sent. In the
1774 "osname" field there may be several sub-fields, comma separated. The data we
1775 actually want to save follows the third colon. Some systems put leading spaces
1776 in it - we discard those. */
1778 if (sscanf(CS buffer + qlen, "%d , %d%n", &received_sender_port,
1779 &received_interface_port, &n) != 2 ||
1780 received_sender_port != sender_host_port ||
1781 received_interface_port != interface_port)
1784 p = buffer + qlen + n;
1785 while(isspace(*p)) p++;
1786 if (*p++ != ':') goto END_OFF;
1787 while(isspace(*p)) p++;
1788 if (Ustrncmp(p, "USERID", 6) != 0) goto END_OFF;
1790 while(isspace(*p)) p++;
1791 if (*p++ != ':') goto END_OFF;
1792 while (*p != 0 && *p != ':') p++;
1793 if (*p++ == 0) goto END_OFF;
1794 while(isspace(*p)) p++;
1795 if (*p == 0) goto END_OFF;
1797 /* The rest of the line is the data we want. We turn it into printing
1798 characters when we save it, so that it cannot mess up the format of any logging
1799 or Received: lines into which it gets inserted. We keep a maximum of 127
1802 sender_ident = string_printing(string_copyn(p, 127));
1803 DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident);
1813 /*************************************************
1814 * Match host to a single host-list item *
1815 *************************************************/
1817 /* This function compares a host (name or address) against a single item
1818 from a host list. The host name gets looked up if it is needed and is not
1819 already known. The function is called from verify_check_this_host() via
1820 match_check_list(), which is why most of its arguments are in a single block.
1823 arg the argument block (see below)
1824 ss the host-list item
1825 valueptr where to pass back looked up data, or NULL
1826 error for error message when returning ERROR
1829 host_name (a) the host name, or
1830 (b) NULL, implying use sender_host_name and
1831 sender_host_aliases, looking them up if required, or
1832 (c) the empty string, meaning that only IP address matches
1834 host_address the host address
1835 host_ipv4 the IPv4 address taken from an IPv6 one
1839 DEFER lookup deferred
1840 ERROR (a) failed to find the host name or IP address, or
1841 (b) unknown lookup type specified, or
1842 (c) host name encountered when only IP addresses are
1847 check_host(void *arg, uschar *ss, uschar **valueptr, uschar **error)
1849 check_host_block *cb = (check_host_block *)arg;
1852 BOOL iplookup = FALSE;
1853 BOOL isquery = FALSE;
1854 BOOL isiponly = cb->host_name != NULL && cb->host_name[0] == 0;
1859 /* Optimize for the special case when the pattern is "*". */
1861 if (*ss == '*' && ss[1] == 0) return OK;
1863 /* If the pattern is empty, it matches only in the case when there is no host -
1864 this can occur in ACL checking for SMTP input using the -bs option. In this
1865 situation, the host address is the empty string. */
1867 if (cb->host_address[0] == 0) return (*ss == 0)? OK : FAIL;
1868 if (*ss == 0) return FAIL;
1870 /* If the pattern is precisely "@" then match against the primary host name,
1871 provided that host name matching is permitted; if it's "@[]" match against the
1872 local host's IP addresses. */
1878 if (isiponly) return ERROR;
1879 ss = primary_hostname;
1881 else if (Ustrcmp(ss, "@[]") == 0)
1883 ip_address_item *ip;
1884 for (ip = host_find_interfaces(); ip != NULL; ip = ip->next)
1885 if (Ustrcmp(ip->address, cb->host_address) == 0) return OK;
1890 /* If the pattern is an IP address, optionally followed by a bitmask count, do
1891 a (possibly masked) comparision with the current IP address. */
1893 if (string_is_ip_address(ss, &maskoffset) > 0)
1894 return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL);
1896 /* See if there is a semicolon in the pattern */
1898 semicolon = Ustrchr(ss, ';');
1900 /* If we are doing an IP address only match, then all lookups must be IP
1905 iplookup = semicolon != NULL;
1908 /* Otherwise, if the item is of the form net[n]-lookup;<file|query> then it is
1909 a lookup on a masked IP network, in textual form. The net- stuff really only
1910 applies to single-key lookups where the key is implicit. For query-style
1911 lookups the key is specified in the query. From release 4.30, the use of net-
1912 for query style is no longer needed, but we retain it for backward
1915 else if (Ustrncmp(ss, "net", 3) == 0 && semicolon != NULL)
1918 for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0';
1919 if (mlen == 0 && t == ss+3) mlen = -1; /* No mask supplied */
1920 iplookup = (*t++ == '-');
1923 /* Do the IP address lookup if that is indeed what we have */
1931 uschar *filename, *key, *result;
1934 /* Find the search type */
1936 search_type = search_findtype(t, semicolon - t);
1938 if (search_type < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
1939 search_error_message);
1941 /* Adjust parameters for the type of lookup. For a query-style lookup, there
1942 is no file name, and the "key" is just the query. For query-style with a file
1943 name, we have to fish the file off the start of the query. For a single-key
1944 lookup, the key is the current IP address, masked appropriately, and
1945 reconverted to text form, with the mask appended. For IPv6 addresses, specify
1946 dot separators instead of colons. */
1948 if (mac_islookup(search_type, lookup_absfilequery))
1950 filename = semicolon + 1;
1952 while (*key != 0 && !isspace(*key)) key++;
1953 filename = string_copyn(filename, key - filename);
1954 while (isspace(*key)) key++;
1956 else if (mac_islookup(search_type, lookup_querystyle))
1959 key = semicolon + 1;
1963 insize = host_aton(cb->host_address, incoming);
1964 host_mask(insize, incoming, mlen);
1965 (void)host_nmtoa(insize, incoming, mlen, buffer, '.');
1967 filename = semicolon + 1;
1970 /* Now do the actual lookup; note that there is no search_close() because
1971 of the caching arrangements. */
1973 handle = search_open(filename, search_type, 0, NULL, NULL);
1974 if (handle == NULL) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
1975 search_error_message);
1976 result = search_find(handle, filename, key, -1, NULL, 0, 0, NULL);
1977 if (valueptr != NULL) *valueptr = result;
1978 return (result != NULL)? OK : search_find_defer? DEFER: FAIL;
1981 /* The pattern is not an IP address or network reference of any kind. That is,
1982 it is a host name pattern. If this is an IP only match, there's an error in the
1987 *error = US"cannot match host name in match_ip list";
1991 /* Check the characters of the pattern to see if they comprise only letters,
1992 digits, full stops, and hyphens (the constituents of domain names). Allow
1993 underscores, as they are all too commonly found. Sigh. Also, if
1994 allow_utf8_domains is set, allow top-bit characters. */
1996 for (t = ss; *t != 0; t++)
1997 if (!isalnum(*t) && *t != '.' && *t != '-' && *t != '_' &&
1998 (!allow_utf8_domains || *t < 128)) break;
2000 /* If the pattern is a complete domain name, with no fancy characters, look up
2001 its IP address and match against that. Note that a multi-homed host will add
2002 items to the chain. */
2012 rc = host_find_byname(&h, NULL, NULL, FALSE);
2013 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2016 for (hh = &h; hh != NULL; hh = hh->next)
2018 if (Ustrcmp(hh->address, (Ustrchr(hh->address, ':') == NULL)?
2019 cb->host_ipv4 : cb->host_address) == 0)
2024 if (rc == HOST_FIND_AGAIN) return DEFER;
2025 *error = string_sprintf("failed to find IP address for %s", ss);
2029 /* Almost all subsequent comparisons require the host name, and can be done
2030 using the general string matching function. When this function is called for
2031 outgoing hosts, the name is always given explicitly. If it is NULL, it means we
2032 must use sender_host_name and its aliases, looking them up if necessary. */
2034 if (cb->host_name != NULL) /* Explicit host name given */
2035 return match_check_string(cb->host_name, ss, -1, TRUE, TRUE, TRUE,
2038 /* Host name not given; in principle we need the sender host name and its
2039 aliases. However, for query-style lookups, we do not need the name if the
2040 query does not contain $sender_host_name. From release 4.23, a reference to
2041 $sender_host_name causes it to be looked up, so we don't need to do the lookup
2044 if ((semicolon = Ustrchr(ss, ';')) != NULL)
2047 int partial, affixlen, starflags, id;
2050 id = search_findtype_partial(ss, &partial, &affix, &affixlen, &starflags);
2053 if (id < 0) /* Unknown lookup type */
2055 log_write(0, LOG_MAIN|LOG_PANIC, "%s in host list item \"%s\"",
2056 search_error_message, ss);
2059 isquery = mac_islookup(id, lookup_querystyle|lookup_absfilequery);
2064 switch(match_check_string(US"", ss, -1, TRUE, TRUE, TRUE, valueptr))
2067 case DEFER: return DEFER;
2068 default: return FAIL;
2072 /* Not a query-style lookup; must ensure the host name is present, and then we
2073 do a check on the name and all its aliases. */
2075 if (sender_host_name == NULL)
2077 HDEBUG(D_host_lookup)
2078 debug_printf("sender host name required, to match against %s\n", ss);
2079 if (host_lookup_failed || host_name_lookup() != OK)
2081 *error = string_sprintf("failed to find host name for %s",
2082 sender_host_address);;
2085 host_build_sender_fullhost();
2088 /* Match on the sender host name, using the general matching function */
2090 switch(match_check_string(sender_host_name, ss, -1, TRUE, TRUE, TRUE,
2094 case DEFER: return DEFER;
2097 /* If there are aliases, try matching on them. */
2099 aliases = sender_host_aliases;
2100 while (*aliases != NULL)
2102 switch(match_check_string(*aliases++, ss, -1, TRUE, TRUE, TRUE, valueptr))
2105 case DEFER: return DEFER;
2114 /*************************************************
2115 * Check a specific host matches a host list *
2116 *************************************************/
2118 /* This function is passed a host list containing items in a number of
2119 different formats and the identity of a host. Its job is to determine whether
2120 the given host is in the set of hosts defined by the list. The host name is
2121 passed as a pointer so that it can be looked up if needed and not already
2122 known. This is commonly the case when called from verify_check_host() to check
2123 an incoming connection. When called from elsewhere the host name should usually
2126 This function is now just a front end to match_check_list(), which runs common
2127 code for scanning a list. We pass it the check_host() function to perform a
2131 listptr pointer to the host list
2132 cache_bits pointer to cache for named lists, or NULL
2133 host_name the host name or NULL, implying use sender_host_name and
2134 sender_host_aliases, looking them up if required
2135 host_address the IP address
2136 valueptr if not NULL, data from a lookup is passed back here
2138 Returns: OK if the host is in the defined set
2139 FAIL if the host is not in the defined set,
2140 DEFER if a data lookup deferred (not a host lookup)
2142 If the host name was needed in order to make a comparison, and could not be
2143 determined from the IP address, the result is FAIL unless the item
2144 "+allow_unknown" was met earlier in the list, in which case OK is returned. */
2147 verify_check_this_host(uschar **listptr, unsigned int *cache_bits,
2148 uschar *host_name, uschar *host_address, uschar **valueptr)
2151 unsigned int *local_cache_bits = cache_bits;
2152 uschar *save_host_address = deliver_host_address;
2153 check_host_block cb;
2154 cb.host_name = host_name;
2155 cb.host_address = host_address;
2157 if (valueptr != NULL) *valueptr = NULL;
2159 /* If the host address starts off ::ffff: it is an IPv6 address in
2160 IPv4-compatible mode. Find the IPv4 part for checking against IPv4
2163 cb.host_ipv4 = (Ustrncmp(host_address, "::ffff:", 7) == 0)?
2164 host_address + 7 : host_address;
2166 /* During the running of the check, put the IP address into $host_address. In
2167 the case of calls from the smtp transport, it will already be there. However,
2168 in other calls (e.g. when testing ignore_target_hosts), it won't. Just to be on
2169 the safe side, any existing setting is preserved, though as I write this
2170 (November 2004) I can't see any cases where it is actually needed. */
2172 deliver_host_address = host_address;
2173 rc = match_check_list(
2174 listptr, /* the list */
2175 0, /* separator character */
2176 &hostlist_anchor, /* anchor pointer */
2177 &local_cache_bits, /* cache pointer */
2178 check_host, /* function for testing */
2179 &cb, /* argument for function */
2180 MCL_HOST, /* type of check */
2181 (host_address == sender_host_address)?
2182 US"host" : host_address, /* text for debugging */
2183 valueptr); /* where to pass back data */
2184 deliver_host_address = save_host_address;
2191 /*************************************************
2192 * Check the remote host matches a list *
2193 *************************************************/
2195 /* This is a front end to verify_check_this_host(), created because checking
2196 the remote host is a common occurrence. With luck, a good compiler will spot
2197 the tail recursion and optimize it. If there's no host address, this is
2198 command-line SMTP input - check against an empty string for the address.
2201 listptr pointer to the host list
2203 Returns: the yield of verify_check_this_host(),
2204 i.e. OK, FAIL, or DEFER
2208 verify_check_host(uschar **listptr)
2210 return verify_check_this_host(listptr, sender_host_cache, NULL,
2211 (sender_host_address == NULL)? US"" : sender_host_address, NULL);
2218 /*************************************************
2219 * Invert an IP address for a DNS black list *
2220 *************************************************/
2224 buffer where to put the answer
2225 address the address to invert
2229 invert_address(uschar *buffer, uschar *address)
2232 uschar *bptr = buffer;
2234 /* If this is an IPv4 address mapped into IPv6 format, adjust the pointer
2235 to the IPv4 part only. */
2237 if (Ustrncmp(address, "::ffff:", 7) == 0) address += 7;
2239 /* Handle IPv4 address: when HAVE_IPV6 is false, the result of host_aton() is
2242 if (host_aton(address, bin) == 1)
2246 for (i = 0; i < 4; i++)
2248 sprintf(CS bptr, "%d.", x & 255);
2249 while (*bptr) bptr++;
2254 /* Handle IPv6 address. Actually, as far as I know, there are no IPv6 addresses
2255 in any DNS black lists, and the format in which they will be looked up is
2256 unknown. This is just a guess. */
2262 for (j = 3; j >= 0; j--)
2265 for (i = 0; i < 8; i++)
2267 sprintf(CS bptr, "%x.", x & 15);
2268 while (*bptr) bptr++;
2278 /*************************************************
2279 * Perform a single dnsbl lookup *
2280 *************************************************/
2282 /* This function is called from verify_check_dnsbl() below.
2285 domain the outer dnsbl domain (for debug message)
2286 keydomain the current keydomain (for debug message)
2287 query the domain to be looked up
2288 iplist the list of matching IP addresses
2289 bitmask true if bitmask matching is wanted
2290 invert_result true if result to be inverted
2291 defer_return what to return for a defer
2293 Returns: OK if lookup succeeded
2298 one_check_dnsbl(uschar *domain, uschar *keydomain, uschar *query,
2299 uschar *iplist, BOOL bitmask, BOOL invert_result, int defer_return)
2304 dnsbl_cache_block *cb;
2305 int old_pool = store_pool;
2307 /* Look for this query in the cache. */
2309 t = tree_search(dnsbl_cache, query);
2311 /* If not cached from a previous lookup, we must do a DNS lookup, and
2312 cache the result in permanent memory. */
2316 store_pool = POOL_PERM;
2318 /* Set up a tree entry to cache the lookup */
2320 t = store_get(sizeof(tree_node) + Ustrlen(query));
2321 Ustrcpy(t->name, query);
2322 t->data.ptr = cb = store_get(sizeof(dnsbl_cache_block));
2323 (void)tree_insertnode(&dnsbl_cache, t);
2325 /* Do the DNS loopup . */
2327 HDEBUG(D_dnsbl) debug_printf("new DNS lookup for %s\n", query);
2328 cb->rc = dns_basic_lookup(&dnsa, query, T_A);
2329 cb->text_set = FALSE;
2333 /* If the lookup succeeded, cache the RHS address. The code allows for
2334 more than one address - this was for complete generality and the possible
2335 use of A6 records. However, A6 records have been reduced to experimental
2336 status (August 2001) and may die out. So they may never get used at all,
2337 let alone in dnsbl records. However, leave the code here, just in case.
2339 Quite apart from one A6 RR generating multiple addresses, there are DNS
2340 lists that return more than one A record, so we must handle multiple
2341 addresses generated in that way as well. */
2343 if (cb->rc == DNS_SUCCEED)
2346 dns_address **addrp = &(cb->rhs);
2347 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2349 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
2351 if (rr->type == T_A)
2353 dns_address *da = dns_address_from_rr(&dnsa, rr);
2357 while (da->next != NULL) da = da->next;
2358 addrp = &(da->next);
2363 /* If we didn't find any A records, change the return code. This can
2364 happen when there is a CNAME record but there are no A records for what
2367 if (cb->rhs == NULL) cb->rc = DNS_NODATA;
2370 store_pool = old_pool;
2373 /* Previous lookup was cached */
2377 HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
2381 /* We now have the result of the DNS lookup, either newly done, or cached
2382 from a previous call. If the lookup succeeded, check against the address
2383 list if there is one. This may be a positive equality list (introduced by
2384 "="), a negative equality list (introduced by "!="), a positive bitmask
2385 list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/
2387 if (cb->rc == DNS_SUCCEED)
2389 dns_address *da = NULL;
2390 uschar *addlist = cb->rhs->address;
2392 /* For A and AAAA records, there may be multiple addresses from multiple
2393 records. For A6 records (currently not expected to be used) there may be
2394 multiple addresses from a single record. */
2396 for (da = cb->rhs->next; da != NULL; da = da->next)
2397 addlist = string_sprintf("%s, %s", addlist, da->address);
2399 HDEBUG(D_dnsbl) debug_printf("DNS lookup for %s succeeded (yielding %s)\n",
2402 /* Address list check; this can be either for equality, or via a bitmask.
2403 In the latter case, all the bits must match. */
2409 uschar *ptr = iplist;
2411 while (string_nextinlist(&ptr, &ipsep, ip, sizeof(ip)) != NULL)
2413 /* Handle exact matching */
2416 for (da = cb->rhs; da != NULL; da = da->next)
2418 if (Ustrcmp(CS da->address, ip) == 0) break;
2421 /* Handle bitmask matching */
2427 /* At present, all known DNS blocking lists use A records, with
2428 IPv4 addresses on the RHS encoding the information they return. I
2429 wonder if this will linger on as the last vestige of IPv4 when IPv6
2430 is ubiquitous? Anyway, for now we use paranoia code to completely
2431 ignore IPv6 addresses. The default mask is 0, which always matches.
2432 We change this only for IPv4 addresses in the list. */
2434 if (host_aton(ip, address) == 1) mask = address[0];
2436 /* Scan the returned addresses, skipping any that are IPv6 */
2438 for (da = cb->rhs; da != NULL; da = da->next)
2440 if (host_aton(da->address, address) != 1) continue;
2441 if ((address[0] & mask) == mask) break;
2445 /* Break out if a match has been found */
2447 if (da != NULL) break;
2452 (a) No IP address in a positive list matched, or
2453 (b) An IP address in a negative list did match
2455 then behave as if the DNSBL lookup had not succeeded, i.e. the host is
2458 if (invert_result != (da == NULL))
2462 debug_printf("=> but we are not accepting this block class because\n");
2463 debug_printf("=> there was %s match for %c%s\n",
2464 invert_result? "an exclude":"no", bitmask? '&' : '=', iplist);
2470 /* Either there was no IP list, or the record matched. Look up a TXT record
2471 if it hasn't previously been done. */
2475 cb->text_set = TRUE;
2476 if (dns_basic_lookup(&dnsa, query, T_TXT) == DNS_SUCCEED)
2479 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2481 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
2482 if (rr->type == T_TXT) break;
2485 int len = (rr->data)[0];
2486 if (len > 511) len = 127;
2487 store_pool = POOL_PERM;
2488 cb->text = string_sprintf("%.*s", len, (const uschar *)(rr->data+1));
2489 store_pool = old_pool;
2494 dnslist_value = addlist;
2495 dnslist_text = cb->text;
2499 /* There was a problem with the DNS lookup */
2501 if (cb->rc != DNS_NOMATCH && cb->rc != DNS_NODATA)
2503 log_write(L_dnslist_defer, LOG_MAIN,
2504 "DNS list lookup defer (probably timeout) for %s: %s", query,
2505 (defer_return == OK)? US"assumed in list" :
2506 (defer_return == FAIL)? US"assumed not in list" :
2507 US"returned DEFER");
2508 return defer_return;
2511 /* No entry was found in the DNS; continue for next domain */
2515 debug_printf("DNS lookup for %s failed\n", query);
2516 debug_printf("=> that means %s is not listed at %s\n",
2526 /*************************************************
2527 * Check host against DNS black lists *
2528 *************************************************/
2530 /* This function runs checks against a list of DNS black lists, until one
2531 matches. Each item on the list can be of the form
2533 domain=ip-address/key
2535 The domain is the right-most domain that is used for the query, for example,
2536 blackholes.mail-abuse.org. If the IP address is present, there is a match only
2537 if the DNS lookup returns a matching IP address. Several addresses may be
2538 given, comma-separated, for example: x.y.z=127.0.0.1,127.0.0.2.
2540 If no key is given, what is looked up in the domain is the inverted IP address
2541 of the current client host. If a key is given, it is used to construct the
2542 domain for the lookup. For example,
2544 dsn.rfc-ignorant.org/$sender_address_domain
2546 After finding a match in the DNS, the domain is placed in $dnslist_domain, and
2547 then we check for a TXT record for an error message, and if found, save its
2548 value in $dnslist_text. We also cache everything in a tree, to optimize
2551 Note: an address for testing RBL is 192.203.178.39
2552 Note: an address for testing DUL is 192.203.178.4
2553 Note: a domain for testing RFCI is example.tld.dsn.rfc-ignorant.org
2556 listptr the domain/address/data list
2558 Returns: OK successful lookup (i.e. the address is on the list), or
2559 lookup deferred after +include_unknown
2560 FAIL name not found, or no data found for the given type, or
2561 lookup deferred after +exclude_unknown (default)
2562 DEFER lookup failure, if +defer_unknown was set
2566 verify_check_dnsbl(uschar **listptr)
2569 int defer_return = FAIL;
2570 BOOL invert_result = FALSE;
2571 uschar *list = *listptr;
2574 uschar buffer[1024];
2575 uschar query[256]; /* DNS domain max length */
2576 uschar revadd[128]; /* Long enough for IPv6 address */
2578 /* Indicate that the inverted IP address is not yet set up */
2582 /* In case this is the first time the DNS resolver is being used. */
2584 dns_init(FALSE, FALSE);
2586 /* Loop through all the domains supplied, until something matches */
2588 while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
2592 BOOL bitmask = FALSE;
2596 HDEBUG(D_dnsbl) debug_printf("DNS list check: %s\n", domain);
2598 /* Deal with special values that change the behaviour on defer */
2600 if (domain[0] == '+')
2602 if (strcmpic(domain, US"+include_unknown") == 0) defer_return = OK;
2603 else if (strcmpic(domain, US"+exclude_unknown") == 0) defer_return = FAIL;
2604 else if (strcmpic(domain, US"+defer_unknown") == 0) defer_return = DEFER;
2606 log_write(0, LOG_MAIN|LOG_PANIC, "unknown item in dnslist (ignored): %s",
2611 /* See if there's explicit data to be looked up */
2613 key = Ustrchr(domain, '/');
2614 if (key != NULL) *key++ = 0;
2616 /* See if there's a list of addresses supplied after the domain name. This is
2617 introduced by an = or a & character; if preceded by ! we invert the result.
2620 iplist = Ustrchr(domain, '=');
2624 iplist = Ustrchr(domain, '&');
2629 if (iplist > domain && iplist[-1] == '!')
2631 invert_result = TRUE;
2637 /* Check that what we have left is a sensible domain name. There is no reason
2638 why these domains should in fact use the same syntax as hosts and email
2639 domains, but in practice they seem to. However, there is little point in
2640 actually causing an error here, because that would no doubt hold up incoming
2641 mail. Instead, I'll just log it. */
2643 for (s = domain; *s != 0; s++)
2645 if (!isalnum(*s) && *s != '-' && *s != '.')
2647 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
2648 "strange characters - is this right?", domain);
2653 /* If there is no key string, construct the query by adding the domain name
2654 onto the inverted host address, and perform a single DNS lookup. */
2658 if (sender_host_address == NULL) return FAIL; /* can never match */
2659 if (revadd[0] == 0) invert_address(revadd, sender_host_address);
2660 frc = string_format(query, sizeof(query), "%s%s", revadd, domain);
2664 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
2665 "(ignored): %s...", query);
2669 rc = one_check_dnsbl(domain, sender_host_address, query, iplist, bitmask,
2670 invert_result, defer_return);
2674 dnslist_domain = string_copy(domain);
2675 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
2676 sender_host_address, domain);
2679 if (rc != FAIL) return rc; /* OK or DEFER */
2682 /* If there is a key string, it can be a list of domains or IP addresses to
2683 be concatenated with the main domain. */
2690 uschar keybuffer[256];
2692 while ((keydomain = string_nextinlist(&key, &keysep, keybuffer,
2693 sizeof(keybuffer))) != NULL)
2695 if (string_is_ip_address(keydomain, NULL) > 0)
2697 uschar keyrevadd[128];
2698 invert_address(keyrevadd, keydomain);
2699 frc = string_format(query, sizeof(query), "%s%s", keyrevadd, domain);
2703 frc = string_format(query, sizeof(query), "%s.%s", keydomain, domain);
2708 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
2709 "(ignored): %s...", query);
2713 rc = one_check_dnsbl(domain, keydomain, query, iplist, bitmask,
2714 invert_result, defer_return);
2718 dnslist_domain = string_copy(domain);
2719 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
2724 /* If the lookup deferred, remember this fact. We keep trying the rest
2725 of the list to see if we get a useful result, and if we don't, we return
2726 DEFER at the end. */
2728 if (rc == DEFER) defer = TRUE;
2729 } /* continue with next keystring domain/address */
2731 if (defer) return DEFER;
2733 } /* continue with next dnsdb outer domain */
2738 /* End of verify.c */