1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions concerned with verifying things. The original code for callout
9 caching was contributed by Kevin Fleming (but I hacked it around a bit). */
13 #include "transports/smtp.h"
15 #define CUTTHROUGH_CMD_TIMEOUT 30 /* timeout for cutthrough-routing calls */
16 #define CUTTHROUGH_DATA_TIMEOUT 60 /* timeout for cutthrough-routing calls */
17 static smtp_outblock ctblock;
18 uschar ctbuffer[8192];
21 /* Structure for caching DNSBL lookups */
23 typedef struct dnsbl_cache_block {
32 /* Anchor for DNSBL cache */
34 static tree_node *dnsbl_cache = NULL;
37 /* Bits for match_type in one_check_dnsbl() */
42 static uschar cutthrough_response(client_conn_ctx *, char, uschar **, int);
46 /*************************************************
47 * Retrieve a callout cache record *
48 *************************************************/
50 /* If a record exists, check whether it has expired.
53 dbm_file an open hints file
55 type "address" or "domain"
56 positive_expire expire time for positive records
57 negative_expire expire time for negative records
59 Returns: the cache record if a non-expired one exists, else NULL
62 static dbdata_callout_cache *
63 get_callout_cache_record(open_db *dbm_file, const uschar *key, uschar *type,
64 int positive_expire, int negative_expire)
69 dbdata_callout_cache *cache_record;
71 if (!(cache_record = dbfn_read_with_length(dbm_file, key, &length)))
73 HDEBUG(D_verify) debug_printf("callout cache: no %s record found for %s\n", type, key);
77 /* We treat a record as "negative" if its result field is not positive, or if
78 it is a domain record and the postmaster field is negative. */
80 negative = cache_record->result != ccache_accept ||
81 (type[0] == 'd' && cache_record->postmaster_result == ccache_reject);
82 expire = negative? negative_expire : positive_expire;
85 if (now - cache_record->time_stamp > expire)
87 HDEBUG(D_verify) debug_printf("callout cache: %s record expired for %s\n", type, key);
91 /* If this is a non-reject domain record, check for the obsolete format version
92 that doesn't have the postmaster and random timestamps, by looking at the
93 length. If so, copy it to a new-style block, replicating the record's
94 timestamp. Then check the additional timestamps. (There's no point wasting
95 effort if connections are rejected.) */
97 if (type[0] == 'd' && cache_record->result != ccache_reject)
99 if (length == sizeof(dbdata_callout_cache_obs))
101 dbdata_callout_cache *new = store_get(sizeof(dbdata_callout_cache));
102 memcpy(new, cache_record, length);
103 new->postmaster_stamp = new->random_stamp = new->time_stamp;
107 if (now - cache_record->postmaster_stamp > expire)
108 cache_record->postmaster_result = ccache_unknown;
110 if (now - cache_record->random_stamp > expire)
111 cache_record->random_result = ccache_unknown;
114 HDEBUG(D_verify) debug_printf("callout cache: found %s record for %s\n", type, key);
120 /* Check the callout cache.
121 Options * pm_mailfrom may be modified by cache partial results.
123 Return: TRUE if result found
127 cached_callout_lookup(address_item * addr, uschar * address_key,
128 uschar * from_address, int * opt_ptr, uschar ** pm_ptr,
129 int * yield, uschar ** failure_ptr,
130 dbdata_callout_cache * new_domain_record, int * old_domain_res)
132 int options = *opt_ptr;
134 open_db *dbm_file = NULL;
136 /* Open the callout cache database, it it exists, for reading only at this
137 stage, unless caching has been disabled. */
139 if (options & vopt_callout_no_cache)
141 HDEBUG(D_verify) debug_printf("callout cache: disabled by no_cache\n");
143 else if (!(dbm_file = dbfn_open(US"callout", O_RDWR, &dbblock, FALSE)))
145 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
149 /* If a cache database is available see if we can avoid the need to do an
150 actual callout by making use of previously-obtained data. */
152 dbdata_callout_cache_address * cache_address_record;
153 dbdata_callout_cache * cache_record = get_callout_cache_record(dbm_file,
154 addr->domain, US"domain",
155 callout_cache_domain_positive_expire, callout_cache_domain_negative_expire);
157 /* If an unexpired cache record was found for this domain, see if the callout
158 process can be short-circuited. */
162 /* In most cases, if an early command (up to and including MAIL FROM:<>)
163 was rejected, there is no point carrying on. The callout fails. However, if
164 we are doing a recipient verification with use_sender or use_postmaster
165 set, a previous failure of MAIL FROM:<> doesn't count, because this time we
166 will be using a non-empty sender. We have to remember this situation so as
167 not to disturb the cached domain value if this whole verification succeeds
168 (we don't want it turning into "accept"). */
170 *old_domain_res = cache_record->result;
172 if ( cache_record->result == ccache_reject
173 || *from_address == 0 && cache_record->result == ccache_reject_mfnull)
176 debug_printf("callout cache: domain gave initial rejection, or "
177 "does not accept HELO or MAIL FROM:<>\n");
178 setflag(addr, af_verify_nsfail);
179 addr->user_message = US"(result of an earlier callout reused).";
181 *failure_ptr = US"mail";
182 dbfn_close(dbm_file);
186 /* If a previous check on a "random" local part was accepted, we assume
187 that the server does not do any checking on local parts. There is therefore
188 no point in doing the callout, because it will always be successful. If a
189 random check previously failed, arrange not to do it again, but preserve
190 the data in the new record. If a random check is required but hasn't been
191 done, skip the remaining cache processing. */
193 if (options & vopt_callout_random) switch(cache_record->random_result)
197 debug_printf("callout cache: domain accepts random addresses\n");
198 *failure_ptr = US"random";
199 dbfn_close(dbm_file);
200 return TRUE; /* Default yield is OK */
204 debug_printf("callout cache: domain rejects random addresses\n");
205 *opt_ptr = options & ~vopt_callout_random;
206 new_domain_record->random_result = ccache_reject;
207 new_domain_record->random_stamp = cache_record->random_stamp;
212 debug_printf("callout cache: need to check random address handling "
213 "(not cached or cache expired)\n");
214 dbfn_close(dbm_file);
218 /* If a postmaster check is requested, but there was a previous failure,
219 there is again no point in carrying on. If a postmaster check is required,
220 but has not been done before, we are going to have to do a callout, so skip
221 remaining cache processing. */
225 if (cache_record->postmaster_result == ccache_reject)
227 setflag(addr, af_verify_pmfail);
229 debug_printf("callout cache: domain does not accept "
230 "RCPT TO:<postmaster@domain>\n");
232 *failure_ptr = US"postmaster";
233 setflag(addr, af_verify_pmfail);
234 addr->user_message = US"(result of earlier verification reused).";
235 dbfn_close(dbm_file);
238 if (cache_record->postmaster_result == ccache_unknown)
241 debug_printf("callout cache: need to check RCPT "
242 "TO:<postmaster@domain> (not cached or cache expired)\n");
243 dbfn_close(dbm_file);
247 /* If cache says OK, set pm_mailfrom NULL to prevent a redundant
248 postmaster check if the address itself has to be checked. Also ensure
249 that the value in the cache record is preserved (with its old timestamp).
252 HDEBUG(D_verify) debug_printf("callout cache: domain accepts RCPT "
253 "TO:<postmaster@domain>\n");
255 new_domain_record->postmaster_result = ccache_accept;
256 new_domain_record->postmaster_stamp = cache_record->postmaster_stamp;
260 /* We can't give a result based on information about the domain. See if there
261 is an unexpired cache record for this specific address (combined with the
262 sender address if we are doing a recipient callout with a non-empty sender).
265 if (!(cache_address_record = (dbdata_callout_cache_address *)
266 get_callout_cache_record(dbm_file, address_key, US"address",
267 callout_cache_positive_expire, callout_cache_negative_expire)))
269 dbfn_close(dbm_file);
273 if (cache_address_record->result == ccache_accept)
276 debug_printf("callout cache: address record is positive\n");
281 debug_printf("callout cache: address record is negative\n");
282 addr->user_message = US"Previous (cached) callout verification failure";
283 *failure_ptr = US"recipient";
287 /* Close the cache database while we actually do the callout for real. */
289 dbfn_close(dbm_file);
296 /* Write results to callout cache
299 cache_callout_write(dbdata_callout_cache * dom_rec, const uschar * domain,
300 int done, dbdata_callout_cache_address * addr_rec, uschar * address_key)
303 open_db *dbm_file = NULL;
305 /* If we get here with done == TRUE, a successful callout happened, and yield
306 will be set OK or FAIL according to the response to the RCPT command.
307 Otherwise, we looped through the hosts but couldn't complete the business.
308 However, there may be domain-specific information to cache in both cases.
310 The value of the result field in the new_domain record is ccache_unknown if
311 there was an error before or with MAIL FROM:, and errno was not zero,
312 implying some kind of I/O error. We don't want to write the cache in that case.
313 Otherwise the value is ccache_accept, ccache_reject, or ccache_reject_mfnull. */
315 if (dom_rec->result != ccache_unknown)
316 if (!(dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE)))
318 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
322 (void)dbfn_write(dbm_file, domain, dom_rec,
323 (int)sizeof(dbdata_callout_cache));
324 HDEBUG(D_verify) debug_printf("wrote callout cache domain record for %s:\n"
325 " result=%d postmaster=%d random=%d\n",
328 dom_rec->postmaster_result,
329 dom_rec->random_result);
332 /* If a definite result was obtained for the callout, cache it unless caching
335 if (done && addr_rec->result != ccache_unknown)
338 dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE);
341 HDEBUG(D_verify) debug_printf("no callout cache available\n");
345 (void)dbfn_write(dbm_file, address_key, addr_rec,
346 (int)sizeof(dbdata_callout_cache_address));
347 HDEBUG(D_verify) debug_printf("wrote %s callout cache address record for %s\n",
348 addr_rec->result == ccache_accept ? "positive" : "negative",
353 if (dbm_file) dbfn_close(dbm_file);
357 /* Cutthrough-multi. If the existing cached cutthrough connection matches
358 the one we would make for a subsequent recipient, use it. Send the RCPT TO
359 and check the result, nonpipelined as it may be wanted immediately for
360 recipient-verification.
362 It seems simpler to deal with this case separately from the main callout loop.
363 We will need to remember it has sent, or not, so that rcpt-acl tail code
364 can do it there for the non-rcpt-verify case. For this we keep an addresscount.
366 Return: TRUE for a definitive result for the recipient
369 cutthrough_multi(address_item * addr, host_item * host_list,
370 transport_feedback * tf, int * yield)
375 if (addr->transport == cutthrough.addr.transport)
376 for (host = host_list; host; host = host->next)
377 if (Ustrcmp(host->address, cutthrough.host.address) == 0)
380 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
383 deliver_host = host->name;
384 deliver_host_address = host->address;
385 deliver_host_port = host->port;
386 deliver_domain = addr->domain;
387 transport_name = addr->transport->name;
389 host_af = Ustrchr(host->address, ':') ? AF_INET6 : AF_INET;
391 if ( !smtp_get_interface(tf->interface, host_af, addr, &interface,
393 || !smtp_get_port(tf->port, addr, &port, US"callout")
395 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
398 smtp_port_for_connect(host, port);
400 if ( ( interface == cutthrough.interface
402 && cutthrough.interface
403 && Ustrcmp(interface, cutthrough.interface) == 0
405 && host->port == cutthrough.host.port
408 uschar * resp = NULL;
410 /* Match! Send the RCPT TO, set done from the response */
412 smtp_write_command(&ctblock, SCMD_FLUSH, "RCPT TO:<%.1000s>\r\n",
413 transport_rcpt_address(addr,
414 addr->transport->rcpt_include_affixes)) >= 0
415 && cutthrough_response(&cutthrough.cctx, '2', &resp,
416 CUTTHROUGH_DATA_TIMEOUT) == '2';
418 /* This would go horribly wrong if a callout fail was ignored by ACL.
419 We punt by abandoning cutthrough on a reject, like the
424 address_item * na = store_get(sizeof(address_item));
425 *na = cutthrough.addr;
426 cutthrough.addr = *addr;
427 cutthrough.addr.host_used = &cutthrough.host;
428 cutthrough.addr.next = na;
434 cancel_cutthrough_connection(TRUE, US"recipient rejected");
435 if (!resp || errno == ETIMEDOUT)
437 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
442 Ustrcpy(resp, US"connection dropped");
445 string_sprintf("response to \"%s\" was: %s",
446 big_buffer, string_printing(resp));
449 string_sprintf("Callout verification failed:\n%s", resp);
451 /* Hard rejection ends the process */
453 if (resp[0] == '5') /* Address rejected */
461 break; /* host_list */
464 cancel_cutthrough_connection(TRUE, US"incompatible connection");
469 /*************************************************
470 * Do callout verification for an address *
471 *************************************************/
473 /* This function is called from verify_address() when the address has routed to
474 a host list, and a callout has been requested. Callouts are expensive; that is
475 why a cache is used to improve the efficiency.
478 addr the address that's been routed
479 host_list the list of hosts to try
480 tf the transport feedback block
482 ifstring "interface" option from transport, or NULL
483 portstring "port" option from transport, or NULL
484 protocolstring "protocol" option from transport, or NULL
485 callout the per-command callout timeout
486 callout_overall the overall callout timeout (if < 0 use 4*callout)
487 callout_connect the callout connection timeout (if < 0 use callout)
488 options the verification options - these bits are used:
489 vopt_is_recipient => this is a recipient address
490 vopt_callout_no_cache => don't use callout cache
491 vopt_callout_fullpm => if postmaster check, do full one
492 vopt_callout_random => do the "random" thing
493 vopt_callout_recipsender => use real sender for recipient
494 vopt_callout_recippmaster => use postmaster for recipient
495 vopt_callout_hold => lazy close connection
496 se_mailfrom MAIL FROM address for sender verify; NULL => ""
497 pm_mailfrom if non-NULL, do the postmaster check with this sender
499 Returns: OK/FAIL/DEFER
503 do_callout(address_item *addr, host_item *host_list, transport_feedback *tf,
504 int callout, int callout_overall, int callout_connect, int options,
505 uschar *se_mailfrom, uschar *pm_mailfrom)
508 int old_domain_cache_result = ccache_accept;
511 uschar *from_address;
512 uschar *random_local_part = NULL;
513 const uschar *save_deliver_domain = deliver_domain;
514 uschar **failure_ptr = options & vopt_is_recipient
515 ? &recipient_verify_failure : &sender_verify_failure;
516 dbdata_callout_cache new_domain_record;
517 dbdata_callout_cache_address new_address_record;
518 time_t callout_start_time;
520 new_domain_record.result = ccache_unknown;
521 new_domain_record.postmaster_result = ccache_unknown;
522 new_domain_record.random_result = ccache_unknown;
524 memset(&new_address_record, 0, sizeof(new_address_record));
526 /* For a recipient callout, the key used for the address cache record must
527 include the sender address if we are using the real sender in the callout,
528 because that may influence the result of the callout. */
530 if (options & vopt_is_recipient)
531 if (options & vopt_callout_recipsender)
533 from_address = sender_address;
534 address_key = string_sprintf("%s/<%s>", addr->address, sender_address);
535 if (cutthrough.delivery) options |= vopt_callout_no_cache;
537 else if (options & vopt_callout_recippmaster)
539 from_address = string_sprintf("postmaster@%s", qualify_domain_sender);
540 address_key = string_sprintf("%s/<postmaster@%s>", addr->address,
541 qualify_domain_sender);
546 address_key = addr->address;
549 /* For a sender callout, we must adjust the key if the mailfrom address is not
554 from_address = se_mailfrom ? se_mailfrom : US"";
555 address_key = *from_address
556 ? string_sprintf("%s/<%s>", addr->address, from_address) : addr->address;
559 if (cached_callout_lookup(addr, address_key, from_address,
560 &options, &pm_mailfrom, &yield, failure_ptr,
561 &new_domain_record, &old_domain_cache_result))
563 cancel_cutthrough_connection(TRUE, US"cache-hit");
567 if (!addr->transport)
569 HDEBUG(D_verify) debug_printf("cannot callout via null transport\n");
571 else if (Ustrcmp(addr->transport->driver_name, "smtp") != 0)
572 log_write(0, LOG_MAIN|LOG_PANIC|LOG_CONFIG_FOR, "callout transport '%s': %s is non-smtp",
573 addr->transport->name, addr->transport->driver_name);
576 smtp_transport_options_block *ob =
577 (smtp_transport_options_block *)addr->transport->options_block;
580 /* The information wasn't available in the cache, so we have to do a real
581 callout and save the result in the cache for next time, unless no_cache is set,
582 or unless we have a previously cached negative random result. If we are to test
583 with a random local part, ensure that such a local part is available. If not,
584 log the fact, but carry on without randomising. */
586 if (options & vopt_callout_random && callout_random_local_part)
587 if (!(random_local_part = expand_string(callout_random_local_part)))
588 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand "
589 "callout_random_local_part: %s", expand_string_message);
591 /* Default the connect and overall callout timeouts if not set, and record the
592 time we are starting so that we can enforce it. */
594 if (callout_overall < 0) callout_overall = 4 * callout;
595 if (callout_connect < 0) callout_connect = callout;
596 callout_start_time = time(NULL);
598 /* Before doing a real callout, if this is an SMTP connection, flush the SMTP
599 output because a callout might take some time. When PIPELINING is active and
600 there are many recipients, the total time for doing lots of callouts can add up
601 and cause the client to time out. So in this case we forgo the PIPELINING
604 if (smtp_out && !disable_callout_flush) mac_smtp_fflush();
606 clearflag(addr, af_verify_pmfail); /* postmaster callout flag */
607 clearflag(addr, af_verify_nsfail); /* null sender callout flag */
609 /* cutthrough-multi: if a nonfirst rcpt has the same routing as the first,
610 and we are holding a cutthrough conn open, we can just append the rcpt to
611 that conn for verification purposes (and later delivery also). Simplest
612 coding means skipping this whole loop and doing the append separately. */
614 /* Can we re-use an open cutthrough connection? */
615 if ( cutthrough.cctx.sock >= 0
616 && (options & (vopt_callout_recipsender | vopt_callout_recippmaster))
617 == vopt_callout_recipsender
618 && !random_local_part
621 done = cutthrough_multi(addr, host_list, tf, &yield);
623 /* If we did not use a cached connection, make connections to the hosts
624 and do real callouts. The list of hosts is passed in as an argument. */
626 for (host = host_list; host && !done; host = host->next)
630 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
635 DEBUG(D_verify) debug_printf("no IP address for host name %s: skipping\n",
640 /* Check the overall callout timeout */
642 if (time(NULL) - callout_start_time >= callout_overall)
644 HDEBUG(D_verify) debug_printf("overall timeout for callout exceeded\n");
648 /* Set IPv4 or IPv6 */
650 host_af = Ustrchr(host->address, ':') ? AF_INET6 : AF_INET;
652 /* Expand and interpret the interface and port strings. The latter will not
653 be used if there is a host-specific port (e.g. from a manualroute router).
654 This has to be delayed till now, because they may expand differently for
655 different hosts. If there's a failure, log it, but carry on with the
658 deliver_host = host->name;
659 deliver_host_address = host->address;
660 deliver_host_port = host->port;
661 deliver_domain = addr->domain;
662 transport_name = addr->transport->name;
664 if ( !smtp_get_interface(tf->interface, host_af, addr, &interface,
666 || !smtp_get_port(tf->port, addr, &port, US"callout")
668 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
673 sx.host_af = host_af,
675 sx.interface = interface;
676 sx.helo_data = tf->helo_data;
677 sx.tblock = addr->transport;
680 tls_retry_connection:
681 /* Set the address state so that errors are recorded in it */
683 addr->transport_return = PENDING_DEFER;
684 ob->connect_timeout = callout_connect;
685 ob->command_timeout = callout;
687 /* Get the channel set up ready for a message (MAIL FROM being the next
688 SMTP command to send. If we tried TLS but it failed, try again without
691 yield = smtp_setup_conn(&sx, FALSE);
694 && addr->basic_errno == ERRNO_TLSFAILURE
695 && ob->tls_tempfail_tryclear
696 && verify_check_given_host(&ob->hosts_require_tls, host) != OK
699 log_write(0, LOG_MAIN,
700 "%s: callout unencrypted to %s [%s] (not in hosts_require_tls)",
701 addr->message, host->name, host->address);
702 addr->transport_return = PENDING_DEFER;
703 yield = smtp_setup_conn(&sx, TRUE);
708 errno = addr->basic_errno;
709 transport_name = NULL;
710 deliver_host = deliver_host_address = NULL;
711 deliver_domain = save_deliver_domain;
713 /* Failure to accept HELO is cached; this blocks the whole domain for all
714 senders. I/O errors and defer responses are not cached. */
716 if (yield == FAIL && (errno == 0 || errno == ERRNO_SMTPCLOSED))
718 setflag(addr, af_verify_nsfail);
719 new_domain_record.result = ccache_reject;
727 /* If we needed to authenticate, smtp_setup_conn() did that. Copy
728 the AUTH info for logging */
730 addr->authenticator = client_authenticator;
731 addr->auth_id = client_authenticated_id;
733 sx.from_addr = from_address;
734 sx.first_addr = sx.sync_addr = addr;
735 sx.ok = FALSE; /*XXX these 3 last might not be needed for verify? */
737 sx.completed_addr = FALSE;
739 new_domain_record.result = old_domain_cache_result == ccache_reject_mfnull
740 ? ccache_reject_mfnull : ccache_accept;
742 /* Do the random local part check first. Temporarily replace the recipient
743 with the "random" value */
745 if (random_local_part)
747 uschar * main_address = addr->address;
748 const uschar * rcpt_domain = addr->domain;
751 uschar * errstr = NULL;
752 if ( testflag(addr, af_utf8_downcvt)
753 && (rcpt_domain = string_domain_utf8_to_alabel(rcpt_domain,
757 addr->message = errstr;
758 errno = ERRNO_EXPANDFAIL;
759 setflag(addr, af_verify_nsfail);
761 rcpt_domain = US""; /*XXX errorhandling! */
765 /* This would be ok for 1st rcpt of a cutthrough (the case handled here;
766 subsequents are done in cutthrough_multi()), but no way to
767 handle a subsequent because of the RSET vaporising the MAIL FROM.
768 So refuse to support any. Most cutthrough use will not involve
769 random_local_part, so no loss. */
770 cancel_cutthrough_connection(TRUE, US"random-recipient");
772 addr->address = string_sprintf("%s@%.1000s",
773 random_local_part, rcpt_domain);
776 /* If accepted, we aren't going to do any further tests below.
777 Otherwise, cache a real negative response, and get back to the right
778 state to send RCPT. Unless there's some problem such as a dropped
779 connection, we expect to succeed, because the commands succeeded above.
780 However, some servers drop the connection after responding to an
781 invalid recipient, so on (any) error we drop and remake the connection.
782 XXX We don't care about that for postmaster_full. Should we?
784 XXX could we add another flag to the context, and have the common
785 code emit the RSET too? Even pipelined after the RCPT...
786 Then the main-verify call could use it if there's to be a subsequent
788 The sync_responses() would need to be taught about it and we'd
789 need another return code filtering out to here.
791 Avoid using a SIZE option on the MAIL for all random-rcpt checks.
794 sx.avoid_option = OPTION_SIZE;
796 /* Remember when we last did a random test */
797 new_domain_record.random_stamp = time(NULL);
799 if (smtp_write_mail_and_rcpt_cmds(&sx, &yield) == 0)
800 switch(addr->transport_return)
802 case PENDING_OK: /* random was accepted, unfortunately */
803 new_domain_record.random_result = ccache_accept;
804 yield = OK; /* Only usable verify result we can return */
806 *failure_ptr = US"random";
808 case FAIL: /* rejected: the preferred result */
809 new_domain_record.random_result = ccache_reject;
812 /* Between each check, issue RSET, because some servers accept only
813 one recipient after MAIL FROM:<>.
814 XXX We don't care about that for postmaster_full. Should we? */
817 smtp_write_command(&sx.outblock, SCMD_FLUSH, "RSET\r\n") >= 0 &&
818 smtp_read_response(&sx.inblock, sx.buffer, sizeof(sx.buffer),
823 debug_printf_indent("problem after random/rset/mfrom; reopen conn\n");
824 random_local_part = NULL;
826 tls_close(sx.cctx.tls_ctx, TLS_SHUTDOWN_NOWAIT);
828 HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP(close)>>\n");
829 (void)close(sx.cctx.sock);
831 #ifndef DISABLE_EVENT
832 (void) event_raise(addr->transport->event_action,
833 US"tcp:close", NULL);
835 addr->address = main_address;
836 addr->transport_return = PENDING_DEFER;
837 sx.first_addr = sx.sync_addr = addr;
840 sx.completed_addr = FALSE;
841 goto tls_retry_connection;
842 case DEFER: /* 4xx response to random */
843 break; /* Just to be clear. ccache_unknown, !done. */
846 /* Re-setup for main verify, or for the error message when failing */
847 addr->address = main_address;
848 addr->transport_return = PENDING_DEFER;
849 sx.first_addr = sx.sync_addr = addr;
852 sx.completed_addr = FALSE;
857 /* Main verify. For rcpt-verify use SIZE if we know it and we're not cacheing;
858 for sndr-verify never use it. */
862 if (!(options & vopt_is_recipient && options & vopt_callout_no_cache))
863 sx.avoid_option = OPTION_SIZE;
866 switch(smtp_write_mail_and_rcpt_cmds(&sx, &yield))
868 case 0: switch(addr->transport_return) /* ok so far */
870 case PENDING_OK: done = TRUE;
871 new_address_record.result = ccache_accept;
873 case FAIL: done = TRUE;
875 *failure_ptr = US"recipient";
876 new_address_record.result = ccache_reject;
882 case -1: /* MAIL response error */
883 *failure_ptr = US"mail";
884 if (errno == 0 && sx.buffer[0] == '5')
886 setflag(addr, af_verify_nsfail);
887 if (from_address[0] == 0)
888 new_domain_record.result = ccache_reject_mfnull;
891 /* non-MAIL read i/o error */
892 /* non-MAIL response timeout */
893 /* internal error; channel still usable */
894 default: break; /* transmit failed */
898 addr->auth_sndr = client_authenticated_sender;
900 deliver_host = deliver_host_address = NULL;
901 deliver_domain = save_deliver_domain;
903 /* Do postmaster check if requested; if a full check is required, we
904 check for RCPT TO:<postmaster> (no domain) in accordance with RFC 821. */
906 if (done && pm_mailfrom)
908 /* Could possibly shift before main verify, just above, and be ok
909 for cutthrough. But no way to handle a subsequent rcpt, so just
911 cancel_cutthrough_connection(TRUE, US"postmaster verify");
912 HDEBUG(D_acl|D_v) debug_printf_indent("Cutthrough cancelled by presence of postmaster verify\n");
914 done = smtp_write_command(&sx.outblock, SCMD_FLUSH, "RSET\r\n") >= 0
915 && smtp_read_response(&sx.inblock, sx.buffer,
916 sizeof(sx.buffer), '2', callout);
920 uschar * main_address = addr->address;
922 /*XXX oops, affixes */
923 addr->address = string_sprintf("postmaster@%.1000s", addr->domain);
924 addr->transport_return = PENDING_DEFER;
926 sx.from_addr = pm_mailfrom;
927 sx.first_addr = sx.sync_addr = addr;
930 sx.completed_addr = FALSE;
931 sx.avoid_option = OPTION_SIZE;
933 if( smtp_write_mail_and_rcpt_cmds(&sx, &yield) == 0
934 && addr->transport_return == PENDING_OK
938 done = (options & vopt_callout_fullpm) != 0
939 && smtp_write_command(&sx.outblock, SCMD_FLUSH,
940 "RCPT TO:<postmaster>\r\n") >= 0
941 && smtp_read_response(&sx.inblock, sx.buffer,
942 sizeof(sx.buffer), '2', callout);
944 /* Sort out the cache record */
946 new_domain_record.postmaster_stamp = time(NULL);
949 new_domain_record.postmaster_result = ccache_accept;
950 else if (errno == 0 && sx.buffer[0] == '5')
952 *failure_ptr = US"postmaster";
953 setflag(addr, af_verify_pmfail);
954 new_domain_record.postmaster_result = ccache_reject;
957 addr->address = main_address;
960 /* For any failure of the main check, other than a negative response, we just
961 close the connection and carry on. We can identify a negative response by the
962 fact that errno is zero. For I/O errors it will be non-zero
964 Set up different error texts for logging and for sending back to the caller
965 as an SMTP response. Log in all cases, using a one-line format. For sender
966 callouts, give a full response to the caller, but for recipient callouts,
967 don't give the IP address because this may be an internal host whose identity
968 is not to be widely broadcast. */
974 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
975 sx.send_quit = FALSE;
981 extern int acl_where; /* src/acl.c */
983 addr->message = string_sprintf(
984 "response to \"EHLO\" did not include SMTPUTF8");
985 addr->user_message = acl_where == ACL_WHERE_RCPT
986 ? US"533 no support for internationalised mailbox name"
987 : US"550 mailbox unavailable";
993 #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_REQUIRETLS)
994 case ERRNO_REQUIRETLS:
995 addr->user_message = US"530 5.7.4 REQUIRETLS support required";
1001 sx.send_quit = FALSE;
1005 if (*sx.buffer == 0) Ustrcpy(sx.buffer, US"connection dropped");
1007 /*XXX test here is ugly; seem to have a split of responsibility for
1008 building this message. Need to rationalise. Where is it done
1009 before here, and when not?
1010 Not == 5xx resp to MAIL on main-verify
1012 if (!addr->message) addr->message =
1013 string_sprintf("response to \"%s\" was: %s",
1014 big_buffer, string_printing(sx.buffer));
1016 addr->user_message = options & vopt_is_recipient
1017 ? string_sprintf("Callout verification failed:\n%s", sx.buffer)
1018 : string_sprintf("Called: %s\nSent: %s\nResponse: %s",
1019 host->address, big_buffer, sx.buffer);
1021 /* Hard rejection ends the process */
1023 if (sx.buffer[0] == '5') /* Address rejected */
1031 /* End the SMTP conversation and close the connection. */
1033 /* Cutthrough - on a successful connect and recipient-verify with
1034 use-sender and we are 1st rcpt and have no cutthrough conn so far
1035 here is where we want to leave the conn open. Ditto for a lazy-close
1038 if (cutthrough.delivery)
1040 if (addr->transport->filter_command)
1042 cutthrough.delivery= FALSE;
1043 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of transport filter\n");
1045 #ifndef DISABLE_DKIM
1046 if (ob->dkim.dkim_domain)
1048 cutthrough.delivery= FALSE;
1049 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of DKIM signing\n");
1052 #ifdef EXPERIMENTAL_ARC
1055 cutthrough.delivery= FALSE;
1056 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of ARC signing\n");
1061 if ( (cutthrough.delivery || options & vopt_callout_hold)
1065 && (options & (vopt_callout_recipsender|vopt_callout_recippmaster|vopt_success_on_redirect))
1066 == vopt_callout_recipsender
1067 && !random_local_part
1069 && cutthrough.cctx.sock < 0
1073 HDEBUG(D_acl|D_v) debug_printf_indent("holding verify callout open for %s\n",
1075 ? "cutthrough delivery" : "potential further verifies and delivery");
1077 cutthrough.callout_hold_only = !cutthrough.delivery;
1078 cutthrough.is_tls = tls_out.active.sock >= 0;
1079 /* We assume no buffer in use in the outblock */
1080 cutthrough.cctx = sx.cctx;
1081 cutthrough.nrcpt = 1;
1082 cutthrough.transport = addr->transport->name;
1083 cutthrough.interface = interface;
1084 cutthrough.snd_port = sending_port;
1085 cutthrough.peer_options = smtp_peer_options;
1086 cutthrough.host = *host;
1088 int oldpool = store_pool;
1089 store_pool = POOL_PERM;
1090 cutthrough.snd_ip = string_copy(sending_ip_address);
1091 cutthrough.host.name = string_copy(host->name);
1092 cutthrough.host.address = string_copy(host->address);
1093 store_pool = oldpool;
1095 cutthrough.addr = *addr; /* Save the address_item for later logging */
1096 cutthrough.addr.next = NULL;
1097 cutthrough.addr.host_used = &cutthrough.host;
1099 *(cutthrough.addr.parent = store_get(sizeof(address_item))) =
1101 ctblock.buffer = ctbuffer;
1102 ctblock.buffersize = sizeof(ctbuffer);
1103 ctblock.ptr = ctbuffer;
1104 /* ctblock.cmd_count = 0; ctblock.authenticating = FALSE; */
1105 ctblock.cctx = &cutthrough.cctx;
1109 /* Ensure no cutthrough on multiple verifies that were incompatible */
1110 if (options & vopt_callout_recipsender)
1111 cancel_cutthrough_connection(TRUE, US"not usable for cutthrough");
1114 (void) smtp_write_command(&sx.outblock, SCMD_FLUSH, "QUIT\r\n");
1116 /* Wait a short time for response, and discard it */
1117 smtp_read_response(&sx.inblock, sx.buffer, sizeof(sx.buffer),
1121 if (sx.cctx.sock >= 0)
1124 if (sx.cctx.tls_ctx)
1126 tls_close(sx.cctx.tls_ctx, TLS_SHUTDOWN_NOWAIT);
1127 sx.cctx.tls_ctx = NULL;
1130 HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP(close)>>\n");
1131 (void)close(sx.cctx.sock);
1133 #ifndef DISABLE_EVENT
1134 (void) event_raise(addr->transport->event_action, US"tcp:close", NULL);
1139 if (!done || yield != OK)
1140 addr->message = string_sprintf("%s [%s] : %s", host->name, host->address,
1142 } /* Loop through all hosts, while !done */
1145 /* If we get here with done == TRUE, a successful callout happened, and yield
1146 will be set OK or FAIL according to the response to the RCPT command.
1147 Otherwise, we looped through the hosts but couldn't complete the business.
1148 However, there may be domain-specific information to cache in both cases. */
1150 if (!(options & vopt_callout_no_cache))
1151 cache_callout_write(&new_domain_record, addr->domain,
1152 done, &new_address_record, address_key);
1154 /* Failure to connect to any host, or any response other than 2xx or 5xx is a
1155 temporary error. If there was only one host, and a response was received, leave
1156 it alone if supplying details. Otherwise, give a generic response. */
1160 uschar * dullmsg = string_sprintf("Could not complete %s verify callout",
1161 options & vopt_is_recipient ? "recipient" : "sender");
1164 addr->message = host_list->next || !addr->message
1165 ? dullmsg : string_sprintf("%s: %s", dullmsg, addr->message);
1167 addr->user_message = smtp_return_error_details
1168 ? string_sprintf("%s for <%s>.\n"
1169 "The mail server(s) for the domain may be temporarily unreachable, or\n"
1170 "they may be permanently unreachable from this server. In the latter case,\n%s",
1171 dullmsg, addr->address,
1172 options & vopt_is_recipient
1173 ? "the address will never be accepted."
1174 : "you need to change the address or create an MX record for its domain\n"
1175 "if it is supposed to be generally accessible from the Internet.\n"
1176 "Talk to your mail administrator for details.")
1179 /* Force a specific error code */
1181 addr->basic_errno = ERRNO_CALLOUTDEFER;
1184 /* Come here from within the cache-reading code on fast-track exit. */
1187 tls_modify_variables(&tls_in);
1193 /* Called after recipient-acl to get a cutthrough connection open when
1194 one was requested and a recipient-verify wasn't subsequently done.
1197 open_cutthrough_connection( address_item * addr )
1202 /* Use a recipient-verify-callout to set up the cutthrough connection. */
1203 /* We must use a copy of the address for verification, because it might
1207 HDEBUG(D_acl) debug_printf_indent("----------- %s cutthrough setup ------------\n",
1208 rcpt_count > 1 ? "more" : "start");
1209 rc = verify_address(&addr2, NULL,
1210 vopt_is_recipient | vopt_callout_recipsender | vopt_callout_no_cache,
1211 CUTTHROUGH_CMD_TIMEOUT, -1, -1,
1213 addr->message = addr2.message;
1214 addr->user_message = addr2.user_message;
1215 HDEBUG(D_acl) debug_printf_indent("----------- end cutthrough setup ------------\n");
1221 /* Send given number of bytes from the buffer */
1223 cutthrough_send(int n)
1225 if(cutthrough.cctx.sock < 0)
1231 ? tls_write(cutthrough.cctx.tls_ctx, ctblock.buffer, n, FALSE)
1234 send(cutthrough.cctx.sock, ctblock.buffer, n, 0) > 0
1237 transport_count += n;
1238 ctblock.ptr= ctblock.buffer;
1242 HDEBUG(D_transport|D_acl) debug_printf_indent("cutthrough_send failed: %s\n", strerror(errno));
1249 _cutthrough_puts(uschar * cp, int n)
1253 if(ctblock.ptr >= ctblock.buffer+ctblock.buffersize)
1254 if(!cutthrough_send(ctblock.buffersize))
1257 *ctblock.ptr++ = *cp++;
1262 /* Buffered output of counted data block. Return boolean success */
1264 cutthrough_puts(uschar * cp, int n)
1266 if (cutthrough.cctx.sock < 0) return TRUE;
1267 if (_cutthrough_puts(cp, n)) return TRUE;
1268 cancel_cutthrough_connection(TRUE, US"transmit failed");
1273 cutthrough_data_puts(uschar * cp, int n)
1275 if (cutthrough.delivery) (void) cutthrough_puts(cp, n);
1281 _cutthrough_flush_send(void)
1283 int n = ctblock.ptr - ctblock.buffer;
1286 if(!cutthrough_send(n))
1292 /* Send out any bufferred output. Return boolean success. */
1294 cutthrough_flush_send(void)
1296 if (_cutthrough_flush_send()) return TRUE;
1297 cancel_cutthrough_connection(TRUE, US"transmit failed");
1303 cutthrough_put_nl(void)
1305 return cutthrough_puts(US"\r\n", 2);
1310 cutthrough_data_put_nl(void)
1312 cutthrough_data_puts(US"\r\n", 2);
1316 /* Get and check response from cutthrough target */
1318 cutthrough_response(client_conn_ctx * cctx, char expect, uschar ** copy, int timeout)
1320 smtp_inblock inblock;
1321 uschar inbuffer[4096];
1322 uschar responsebuffer[4096];
1324 inblock.buffer = inbuffer;
1325 inblock.buffersize = sizeof(inbuffer);
1326 inblock.ptr = inbuffer;
1327 inblock.ptrend = inbuffer;
1328 inblock.cctx = cctx;
1329 if(!smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), expect, timeout))
1330 cancel_cutthrough_connection(TRUE, US"target timeout on read");
1335 *copy = cp = string_copy(responsebuffer);
1336 /* Trim the trailing end of line */
1337 cp += Ustrlen(responsebuffer);
1338 if(cp > *copy && cp[-1] == '\n') *--cp = '\0';
1339 if(cp > *copy && cp[-1] == '\r') *--cp = '\0';
1342 return responsebuffer[0];
1346 /* Negotiate dataphase with the cutthrough target, returning success boolean */
1348 cutthrough_predata(void)
1350 if(cutthrough.cctx.sock < 0 || cutthrough.callout_hold_only)
1353 HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP>> DATA\n");
1354 cutthrough_puts(US"DATA\r\n", 6);
1355 cutthrough_flush_send();
1357 /* Assume nothing buffered. If it was it gets ignored. */
1358 return cutthrough_response(&cutthrough.cctx, '3', NULL, CUTTHROUGH_DATA_TIMEOUT) == '3';
1362 /* tctx arg only to match write_chunk() */
1364 cutthrough_write_chunk(transport_ctx * tctx, uschar * s, int len)
1367 while(s && (s2 = Ustrchr(s, '\n')))
1369 if(!cutthrough_puts(s, s2-s) || !cutthrough_put_nl())
1377 /* Buffered send of headers. Return success boolean. */
1378 /* Expands newlines to wire format (CR,NL). */
1379 /* Also sends header-terminating blank line. */
1381 cutthrough_headers_send(void)
1385 if(cutthrough.cctx.sock < 0 || cutthrough.callout_hold_only)
1388 /* We share a routine with the mainline transport to handle header add/remove/rewrites,
1389 but having a separate buffered-output function (for now)
1391 HDEBUG(D_acl) debug_printf_indent("----------- start cutthrough headers send -----------\n");
1393 tctx.u.fd = cutthrough.cctx.sock;
1394 tctx.tblock = cutthrough.addr.transport;
1395 tctx.addr = &cutthrough.addr;
1396 tctx.check_string = US".";
1397 tctx.escape_string = US"..";
1398 /*XXX check under spool_files_wireformat. Might be irrelevant */
1399 tctx.options = topt_use_crlf;
1401 if (!transport_headers_send(&tctx, &cutthrough_write_chunk))
1404 HDEBUG(D_acl) debug_printf_indent("----------- done cutthrough headers send ------------\n");
1410 close_cutthrough_connection(const uschar * why)
1412 int fd = cutthrough.cctx.sock;
1415 /* We could be sending this after a bunch of data, but that is ok as
1416 the only way to cancel the transfer in dataphase is to drop the tcp
1417 conn before the final dot.
1419 client_conn_ctx tmp_ctx = cutthrough.cctx;
1420 ctblock.ptr = ctbuffer;
1421 HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP>> QUIT\n");
1422 _cutthrough_puts(US"QUIT\r\n", 6); /* avoid recursion */
1423 _cutthrough_flush_send();
1424 cutthrough.cctx.sock = -1; /* avoid recursion via read timeout */
1425 cutthrough.nrcpt = 0; /* permit re-cutthrough on subsequent message */
1427 /* Wait a short time for response, and discard it */
1428 cutthrough_response(&tmp_ctx, '2', NULL, 1);
1431 if (cutthrough.is_tls)
1433 tls_close(cutthrough.cctx.tls_ctx, TLS_SHUTDOWN_NOWAIT);
1434 cutthrough.cctx.tls_ctx = NULL;
1435 cutthrough.is_tls = FALSE;
1438 HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP(close)>>\n");
1440 HDEBUG(D_acl) debug_printf_indent("----------- cutthrough shutdown (%s) ------------\n", why);
1442 ctblock.ptr = ctbuffer;
1446 cancel_cutthrough_connection(BOOL close_noncutthrough_verifies, const uschar * why)
1448 if (cutthrough.delivery || close_noncutthrough_verifies)
1449 close_cutthrough_connection(why);
1450 cutthrough.delivery = cutthrough.callout_hold_only = FALSE;
1455 release_cutthrough_connection(const uschar * why)
1457 if (cutthrough.cctx.sock < 0) return;
1458 HDEBUG(D_acl) debug_printf_indent("release cutthrough conn: %s\n", why);
1459 cutthrough.cctx.sock = -1;
1460 cutthrough.cctx.tls_ctx = NULL;
1461 cutthrough.delivery = cutthrough.callout_hold_only = FALSE;
1467 /* Have senders final-dot. Send one to cutthrough target, and grab the response.
1468 Log an OK response as a transmission.
1469 Close the connection.
1470 Return smtp response-class digit.
1473 cutthrough_finaldot(void)
1476 address_item * addr;
1477 HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP>> .\n");
1479 /* Assume data finshed with new-line */
1480 if( !cutthrough_puts(US".", 1)
1481 || !cutthrough_put_nl()
1482 || !cutthrough_flush_send()
1484 return cutthrough.addr.message;
1486 res = cutthrough_response(&cutthrough.cctx, '2', &cutthrough.addr.message,
1487 CUTTHROUGH_DATA_TIMEOUT);
1488 for (addr = &cutthrough.addr; addr; addr = addr->next)
1490 addr->message = cutthrough.addr.message;
1494 delivery_log(LOG_MAIN, addr, (int)'>', NULL);
1495 close_cutthrough_connection(US"delivered");
1499 delivery_log(LOG_MAIN, addr, 0,
1500 US"tmp-reject from cutthrough after DATA:");
1504 delivery_log(LOG_MAIN|LOG_REJECT, addr, 0,
1505 US"rejected after DATA:");
1512 return cutthrough.addr.message;
1517 /*************************************************
1518 * Copy error to toplevel address *
1519 *************************************************/
1521 /* This function is used when a verify fails or defers, to ensure that the
1522 failure or defer information is in the original toplevel address. This applies
1523 when an address is redirected to a single new address, and the failure or
1524 deferral happens to the child address.
1527 vaddr the verify address item
1528 addr the final address item
1531 Returns: the value of YIELD
1535 copy_error(address_item *vaddr, address_item *addr, int yield)
1539 vaddr->message = addr->message;
1540 vaddr->user_message = addr->user_message;
1541 vaddr->basic_errno = addr->basic_errno;
1542 vaddr->more_errno = addr->more_errno;
1543 vaddr->prop.address_data = addr->prop.address_data;
1544 copyflag(vaddr, addr, af_pass_message);
1552 /**************************************************
1553 * printf that automatically handles TLS if needed *
1554 ***************************************************/
1556 /* This function is used by verify_address() as a substitute for all fprintf()
1557 calls; a direct fprintf() will not produce output in a TLS SMTP session, such
1558 as a response to an EXPN command. smtp_in.c makes smtp_printf available but
1559 that assumes that we always use the smtp_out FILE* when not using TLS or the
1560 ssl buffer when we are. Instead we take a FILE* parameter and check to see if
1561 that is smtp_out; if so, smtp_printf() with TLS support, otherwise regular
1565 f the candidate FILE* to write to
1566 format format string
1567 ... optional arguments
1573 static void PRINTF_FUNCTION(2,3)
1574 respond_printf(FILE *f, const char *format, ...)
1578 va_start(ap, format);
1579 if (smtp_out && (f == smtp_out))
1580 smtp_vprintf(format, FALSE, ap);
1582 vfprintf(f, format, ap);
1588 /*************************************************
1589 * Verify an email address *
1590 *************************************************/
1592 /* This function is used both for verification (-bv and at other times) and
1593 address testing (-bt), which is indicated by address_test_mode being set.
1596 vaddr contains the address to verify; the next field in this block
1598 f if not NULL, write the result to this file
1599 options various option bits:
1600 vopt_fake_sender => this sender verify is not for the real
1601 sender (it was verify=sender=xxxx or an address from a
1602 header line) - rewriting must not change sender_address
1603 vopt_is_recipient => this is a recipient address, otherwise
1604 it's a sender address - this affects qualification and
1605 rewriting and messages from callouts
1606 vopt_qualify => qualify an unqualified address; else error
1607 vopt_expn => called from SMTP EXPN command
1608 vopt_success_on_redirect => when a new address is generated
1609 the verification instantly succeeds
1611 These ones are used by do_callout() -- the options variable
1614 vopt_callout_fullpm => if postmaster check, do full one
1615 vopt_callout_no_cache => don't use callout cache
1616 vopt_callout_random => do the "random" thing
1617 vopt_callout_recipsender => use real sender for recipient
1618 vopt_callout_recippmaster => use postmaster for recipient
1620 callout if > 0, specifies that callout is required, and gives timeout
1621 for individual commands
1622 callout_overall if > 0, gives overall timeout for the callout function;
1623 if < 0, a default is used (see do_callout())
1624 callout_connect the connection timeout for callouts
1625 se_mailfrom when callout is requested to verify a sender, use this
1626 in MAIL FROM; NULL => ""
1627 pm_mailfrom when callout is requested, if non-NULL, do the postmaster
1628 thing and use this as the sender address (may be "")
1630 routed if not NULL, set TRUE if routing succeeded, so we can
1631 distinguish between routing failed and callout failed
1633 Returns: OK address verified
1634 FAIL address failed to verify
1635 DEFER can't tell at present
1639 verify_address(address_item *vaddr, FILE *f, int options, int callout,
1640 int callout_overall, int callout_connect, uschar *se_mailfrom,
1641 uschar *pm_mailfrom, BOOL *routed)
1644 BOOL full_info = (f == NULL)? FALSE : (debug_selector != 0);
1645 BOOL expn = (options & vopt_expn) != 0;
1646 BOOL success_on_redirect = (options & vopt_success_on_redirect) != 0;
1649 int verify_type = expn? v_expn :
1650 address_test_mode? v_none :
1651 options & vopt_is_recipient? v_recipient : v_sender;
1652 address_item *addr_list;
1653 address_item *addr_new = NULL;
1654 address_item *addr_remote = NULL;
1655 address_item *addr_local = NULL;
1656 address_item *addr_succeed = NULL;
1657 uschar **failure_ptr = options & vopt_is_recipient
1658 ? &recipient_verify_failure : &sender_verify_failure;
1659 uschar *ko_prefix, *cr;
1660 uschar *address = vaddr->address;
1661 uschar *save_sender;
1662 uschar null_sender[] = { 0 }; /* Ensure writeable memory */
1664 /* Clear, just in case */
1666 *failure_ptr = NULL;
1668 /* Set up a prefix and suffix for error message which allow us to use the same
1669 output statements both in EXPN mode (where an SMTP response is needed) and when
1670 debugging with an output file. */
1674 ko_prefix = US"553 ";
1677 else ko_prefix = cr = US"";
1679 /* Add qualify domain if permitted; otherwise an unqualified address fails. */
1681 if (parse_find_at(address) == NULL)
1683 if (!(options & vopt_qualify))
1686 respond_printf(f, "%sA domain is required for \"%s\"%s\n",
1687 ko_prefix, address, cr);
1688 *failure_ptr = US"qualify";
1691 address = rewrite_address_qualify(address, options & vopt_is_recipient);
1696 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1697 debug_printf("%s %s\n", address_test_mode? "Testing" : "Verifying", address);
1700 /* Rewrite and report on it. Clear the domain and local part caches - these
1701 may have been set by domains and local part tests during an ACL. */
1703 if (global_rewrite_rules)
1705 uschar *old = address;
1706 address = rewrite_address(address, options & vopt_is_recipient, FALSE,
1707 global_rewrite_rules, rewrite_existflags);
1710 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->localpart_cache[i] = 0;
1711 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->domain_cache[i] = 0;
1712 if (f && !expn) fprintf(f, "Address rewritten as: %s\n", address);
1716 /* If this is the real sender address, we must update sender_address at
1717 this point, because it may be referred to in the routers. */
1719 if (!(options & (vopt_fake_sender|vopt_is_recipient)))
1720 sender_address = address;
1722 /* If the address was rewritten to <> no verification can be done, and we have
1723 to return OK. This rewriting is permitted only for sender addresses; for other
1724 addresses, such rewriting fails. */
1726 if (!address[0]) return OK;
1728 /* Flip the legacy TLS-related variables over to the outbound set in case
1729 they're used in the context of a transport used by verification. Reset them
1730 at exit from this routine (so no returns allowed from here on). */
1732 tls_modify_variables(&tls_out);
1734 /* Save a copy of the sender address for re-instating if we change it to <>
1735 while verifying a sender address (a nice bit of self-reference there). */
1737 save_sender = sender_address;
1739 /* Observability variable for router/transport use */
1741 verify_mode = options & vopt_is_recipient ? US"R" : US"S";
1743 /* Update the address structure with the possibly qualified and rewritten
1744 address. Set it up as the starting address on the chain of new addresses. */
1746 vaddr->address = address;
1749 /* We need a loop, because an address can generate new addresses. We must also
1750 cope with generated pipes and files at the top level. (See also the code and
1751 comment in deliver.c.) However, it is usually the case that the router for
1752 user's .forward files has its verify flag turned off.
1754 If an address generates more than one child, the loop is used only when
1755 full_info is set, and this can only be set locally. Remote enquiries just get
1756 information about the top level address, not anything that it generated. */
1761 address_item *addr = addr_new;
1763 addr_new = addr->next;
1768 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1769 debug_printf("Considering %s\n", addr->address);
1772 /* Handle generated pipe, file or reply addresses. We don't get these
1773 when handling EXPN, as it does only one level of expansion. */
1775 if (testflag(addr, af_pfr))
1782 if (addr->address[0] == '>')
1784 allow = testflag(addr, af_allow_reply);
1785 fprintf(f, "%s -> mail %s", addr->parent->address, addr->address + 1);
1789 allow = addr->address[0] == '|'
1790 ? testflag(addr, af_allow_pipe) : testflag(addr, af_allow_file);
1791 fprintf(f, "%s -> %s", addr->parent->address, addr->address);
1794 if (addr->basic_errno == ERRNO_BADTRANSPORT)
1795 fprintf(f, "\n*** Error in setting up pipe, file, or autoreply:\n"
1796 "%s\n", addr->message);
1798 fprintf(f, "\n transport = %s\n", addr->transport->name);
1800 fprintf(f, " *** forbidden ***\n");
1805 /* Just in case some router parameter refers to it. */
1807 return_path = addr->prop.errors_address
1808 ? addr->prop.errors_address : sender_address;
1810 /* Split the address into domain and local part, handling the %-hack if
1811 necessary, and then route it. While routing a sender address, set
1812 $sender_address to <> because that is what it will be if we were trying to
1813 send a bounce to the sender. */
1815 if (routed) *routed = FALSE;
1816 if ((rc = deliver_split_address(addr)) == OK)
1818 if (!(options & vopt_is_recipient)) sender_address = null_sender;
1819 rc = route_address(addr, &addr_local, &addr_remote, &addr_new,
1820 &addr_succeed, verify_type);
1821 sender_address = save_sender; /* Put back the real sender */
1824 /* If routing an address succeeded, set the flag that remembers, for use when
1825 an ACL cached a sender verify (in case a callout fails). Then if routing set
1826 up a list of hosts or the transport has a host list, and the callout option
1827 is set, and we aren't in a host checking run, do the callout verification,
1828 and set another flag that notes that a callout happened. */
1832 if (routed) *routed = TRUE;
1835 transport_instance * tp;
1836 host_item * host_list = addr->host_list;
1838 /* Make up some data for use in the case where there is no remote
1841 transport_feedback tf = {
1842 .interface = NULL, /* interface (=> any) */
1844 .protocol = US"smtp",
1846 .helo_data = US"$smtp_active_hostname",
1847 .hosts_override = FALSE,
1848 .hosts_randomize = FALSE,
1849 .gethostbyname = FALSE,
1850 .qualify_single = TRUE,
1851 .search_parents = FALSE
1854 /* If verification yielded a remote transport, we want to use that
1855 transport's options, so as to mimic what would happen if we were really
1856 sending a message to this address. */
1858 if ((tp = addr->transport) && !tp->info->local)
1860 (void)(tp->setup)(tp, addr, &tf, 0, 0, NULL);
1862 /* If the transport has hosts and the router does not, or if the
1863 transport is configured to override the router's hosts, we must build a
1864 host list of the transport's hosts, and find the IP addresses */
1866 if (tf.hosts && (!host_list || tf.hosts_override))
1869 const uschar *save_deliver_domain = deliver_domain;
1870 uschar *save_deliver_localpart = deliver_localpart;
1872 host_list = NULL; /* Ignore the router's hosts */
1874 deliver_domain = addr->domain;
1875 deliver_localpart = addr->local_part;
1876 s = expand_string(tf.hosts);
1877 deliver_domain = save_deliver_domain;
1878 deliver_localpart = save_deliver_localpart;
1882 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand list of hosts "
1883 "\"%s\" in %s transport for callout: %s", tf.hosts,
1884 tp->name, expand_string_message);
1889 host_item *host, *nexthost;
1890 host_build_hostlist(&host_list, s, tf.hosts_randomize);
1892 /* Just ignore failures to find a host address. If we don't manage
1893 to find any addresses, the callout will defer. Note that more than
1894 one address may be found for a single host, which will result in
1895 additional host items being inserted into the chain. Hence we must
1896 save the next host first. */
1898 flags = HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
1899 if (tf.qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
1900 if (tf.search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
1902 for (host = host_list; host; host = nexthost)
1904 nexthost = host->next;
1905 if (tf.gethostbyname ||
1906 string_is_ip_address(host->name, NULL) != 0)
1907 (void)host_find_byname(host, NULL, flags, NULL, TRUE);
1910 const dnssec_domains * dsp = NULL;
1911 if (Ustrcmp(tp->driver_name, "smtp") == 0)
1913 smtp_transport_options_block * ob =
1914 (smtp_transport_options_block *) tp->options_block;
1918 (void) host_find_bydns(host, NULL, flags, NULL, NULL, NULL,
1926 /* Can only do a callout if we have at least one host! If the callout
1927 fails, it will have set ${sender,recipient}_verify_failure. */
1931 HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n");
1932 if (host_checking && !host_checking_callout)
1935 debug_printf("... callout omitted by default when host testing\n"
1936 "(Use -bhc if you want the callouts to happen.)\n");
1941 deliver_set_expansions(addr);
1943 rc = do_callout(addr, host_list, &tf, callout, callout_overall,
1944 callout_connect, options, se_mailfrom, pm_mailfrom);
1949 HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor "
1950 "transport provided a host list, or transport is not smtp\n");
1955 /* Otherwise, any failure is a routing failure */
1957 else *failure_ptr = US"route";
1959 /* A router may return REROUTED if it has set up a child address as a result
1960 of a change of domain name (typically from widening). In this case we always
1961 want to continue to verify the new child. */
1963 if (rc == REROUTED) continue;
1965 /* Handle hard failures */
1972 address_item *p = addr->parent;
1974 respond_printf(f, "%s%s %s", ko_prefix,
1975 full_info ? addr->address : address,
1976 address_test_mode ? "is undeliverable" : "failed to verify");
1977 if (!expn && admin_user)
1979 if (addr->basic_errno > 0)
1980 respond_printf(f, ": %s", strerror(addr->basic_errno));
1982 respond_printf(f, ": %s", addr->message);
1985 /* Show parents iff doing full info */
1987 if (full_info) while (p)
1989 respond_printf(f, "%s\n <-- %s", cr, p->address);
1992 respond_printf(f, "%s\n", cr);
1994 cancel_cutthrough_connection(TRUE, US"routing hard fail");
1998 yield = copy_error(vaddr, addr, FAIL);
2006 else if (rc == DEFER)
2011 address_item *p = addr->parent;
2012 respond_printf(f, "%s%s cannot be resolved at this time", ko_prefix,
2013 full_info? addr->address : address);
2014 if (!expn && admin_user)
2016 if (addr->basic_errno > 0)
2017 respond_printf(f, ": %s", strerror(addr->basic_errno));
2019 respond_printf(f, ": %s", addr->message);
2020 else if (addr->basic_errno <= 0)
2021 respond_printf(f, ": unknown error");
2024 /* Show parents iff doing full info */
2026 if (full_info) while (p)
2028 respond_printf(f, "%s\n <-- %s", cr, p->address);
2031 respond_printf(f, "%s\n", cr);
2033 cancel_cutthrough_connection(TRUE, US"routing soft fail");
2037 yield = copy_error(vaddr, addr, DEFER);
2040 if (yield == OK) yield = DEFER;
2043 /* If we are handling EXPN, we do not want to continue to route beyond
2044 the top level (whose address is in "address"). */
2048 uschar *ok_prefix = US"250-";
2051 if (!addr_local && !addr_remote)
2052 respond_printf(f, "250 mail to <%s> is discarded\r\n", address);
2054 respond_printf(f, "250 <%s>\r\n", address);
2058 address_item *addr2 = addr_new;
2059 addr_new = addr2->next;
2060 if (!addr_new) ok_prefix = US"250 ";
2061 respond_printf(f, "%s<%s>\r\n", ok_prefix, addr2->address);
2067 /* Successful routing other than EXPN. */
2071 /* Handle successful routing when short info wanted. Otherwise continue for
2072 other (generated) addresses. Short info is the operational case. Full info
2073 can be requested only when debug_selector != 0 and a file is supplied.
2075 There is a conflict between the use of aliasing as an alternate email
2076 address, and as a sort of mailing list. If an alias turns the incoming
2077 address into just one address (e.g. J.Caesar->jc44) you may well want to
2078 carry on verifying the generated address to ensure it is valid when
2079 checking incoming mail. If aliasing generates multiple addresses, you
2080 probably don't want to do this. Exim therefore treats the generation of
2081 just a single new address as a special case, and continues on to verify the
2082 generated address. */
2084 if ( !full_info /* Stop if short info wanted AND */
2085 && ( ( !addr_new /* No new address OR */
2086 || addr_new->next /* More than one new address OR */
2087 || testflag(addr_new, af_pfr) /* New address is pfr */
2090 ( addr_new /* At least one new address AND */
2091 && success_on_redirect /* success_on_redirect is set */
2095 if (f) fprintf(f, "%s %s\n",
2096 address, address_test_mode ? "is deliverable" : "verified");
2098 /* If we have carried on to verify a child address, we want the value
2099 of $address_data to be that of the child */
2101 vaddr->prop.address_data = addr->prop.address_data;
2103 /* If stopped because more than one new address, cannot cutthrough */
2105 if (addr_new && addr_new->next)
2106 cancel_cutthrough_connection(TRUE, US"multiple addresses from routing");
2112 } /* Loop for generated addresses */
2114 /* Display the full results of the successful routing, including any generated
2115 addresses. Control gets here only when full_info is set, which requires f not
2116 to be NULL, and this occurs only when a top-level verify is called with the
2117 debugging switch on.
2119 If there are no local and no remote addresses, and there were no pipes, files,
2120 or autoreplies, and there were no errors or deferments, the message is to be
2121 discarded, usually because of the use of :blackhole: in an alias file. */
2123 if (allok && !addr_local && !addr_remote)
2125 fprintf(f, "mail to %s is discarded\n", address);
2129 for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++)
2132 address_item *addr = addr_list;
2133 address_item *p = addr->parent;
2134 transport_instance * tp = addr->transport;
2136 addr_list = addr->next;
2138 fprintf(f, "%s", CS addr->address);
2139 #ifdef EXPERIMENTAL_SRS
2140 if(addr->prop.srs_sender)
2141 fprintf(f, " [srs = %s]", addr->prop.srs_sender);
2144 /* If the address is a duplicate, show something about it. */
2146 if (!testflag(addr, af_pfr))
2149 if ((tnode = tree_search(tree_duplicates, addr->unique)))
2150 fprintf(f, " [duplicate, would not be delivered]");
2151 else tree_add_duplicate(addr->unique, addr);
2154 /* Now show its parents */
2156 for (p = addr->parent; p; p = p->parent)
2157 fprintf(f, "\n <-- %s", p->address);
2160 /* Show router, and transport */
2162 fprintf(f, "router = %s, transport = %s\n",
2163 addr->router->name, tp ? tp->name : US"unset");
2165 /* Show any hosts that are set up by a router unless the transport
2166 is going to override them; fiddle a bit to get a nice format. */
2168 if (addr->host_list && tp && !tp->overrides_hosts)
2173 for (h = addr->host_list; h; h = h->next)
2174 { /* get max lengths of host names, addrs */
2175 int len = Ustrlen(h->name);
2176 if (len > maxlen) maxlen = len;
2177 len = h->address ? Ustrlen(h->address) : 7;
2178 if (len > maxaddlen) maxaddlen = len;
2180 for (h = addr->host_list; h; h = h->next)
2182 fprintf(f, " host %-*s ", maxlen, h->name);
2185 fprintf(f, "[%s%-*c", h->address, maxaddlen+1 - Ustrlen(h->address), ']');
2186 else if (tp->info->local)
2187 fprintf(f, " %-*s ", maxaddlen, ""); /* Omit [unknown] for local */
2189 fprintf(f, "[%s%-*c", "unknown", maxaddlen+1 - 7, ']');
2191 if (h->mx >= 0) fprintf(f, " MX=%d", h->mx);
2192 if (h->port != PORT_NONE) fprintf(f, " port=%d", h->port);
2193 if (running_in_test_harness && h->dnssec == DS_YES) fputs(" AD", f);
2194 if (h->status == hstatus_unusable) fputs(" ** unusable **", f);
2200 /* Yield will be DEFER or FAIL if any one address has, only for full_info (which is
2201 the -bv or -bt case). */
2205 tls_modify_variables(&tls_in);
2213 /*************************************************
2214 * Check headers for syntax errors *
2215 *************************************************/
2217 /* This function checks those header lines that contain addresses, and verifies
2218 that all the addresses therein are 5322-syntactially correct.
2221 msgptr where to put an error message
2228 verify_check_headers(uschar **msgptr)
2234 for (h = header_list; h && yield == OK; h = h->next)
2236 if (h->type != htype_from &&
2237 h->type != htype_reply_to &&
2238 h->type != htype_sender &&
2239 h->type != htype_to &&
2240 h->type != htype_cc &&
2241 h->type != htype_bcc)
2244 colon = Ustrchr(h->text, ':');
2246 while (isspace(*s)) s++;
2248 /* Loop for multiple addresses in the header, enabling group syntax. Note
2249 that we have to reset this after the header has been scanned. */
2251 parse_allow_group = TRUE;
2255 uschar *ss = parse_find_address_end(s, FALSE);
2256 uschar *recipient, *errmess;
2257 int terminator = *ss;
2258 int start, end, domain;
2260 /* Temporarily terminate the string at this point, and extract the
2261 operative address within, allowing group syntax. */
2264 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2267 /* Permit an unqualified address only if the message is local, or if the
2268 sending host is configured to be permitted to send them. */
2270 if (recipient && !domain)
2272 if (h->type == htype_from || h->type == htype_sender)
2274 if (!allow_unqualified_sender) recipient = NULL;
2278 if (!allow_unqualified_recipient) recipient = NULL;
2280 if (recipient == NULL) errmess = US"unqualified address not permitted";
2283 /* It's an error if no address could be extracted, except for the special
2284 case of an empty address. */
2286 if (!recipient && Ustrcmp(errmess, "empty address") != 0)
2288 uschar *verb = US"is";
2293 /* Arrange not to include any white space at the end in the
2294 error message or the header name. */
2296 while (t > s && isspace(t[-1])) t--;
2297 while (tt > h->text && isspace(tt[-1])) tt--;
2299 /* Add the address that failed to the error message, since in a
2300 header with very many addresses it is sometimes hard to spot
2301 which one is at fault. However, limit the amount of address to
2302 quote - cases have been seen where, for example, a missing double
2303 quote in a humungous To: header creates an "address" that is longer
2304 than string_sprintf can handle. */
2313 /* deconst cast ok as we're passing a non-const to string_printing() */
2314 *msgptr = US string_printing(
2315 string_sprintf("%s: failing address in \"%.*s:\" header %s: %.*s",
2316 errmess, (int)(tt - h->text), h->text, verb, len, s));
2319 break; /* Out of address loop */
2322 /* Advance to the next address */
2324 s = ss + (terminator ? 1 : 0);
2325 while (isspace(*s)) s++;
2326 } /* Next address */
2328 parse_allow_group = FALSE;
2329 parse_found_group = FALSE;
2330 } /* Next header unless yield has been set FALSE */
2336 /*************************************************
2337 * Check header names for 8-bit characters *
2338 *************************************************/
2340 /* This function checks for invalid characters in header names. See
2341 RFC 5322, 2.2. and RFC 6532, 3.
2344 msgptr where to put an error message
2351 verify_check_header_names_ascii(uschar **msgptr)
2356 for (h = header_list; h; h = h->next)
2358 colon = Ustrchr(h->text, ':');
2359 for(s = h->text; s < colon; s++)
2360 if ((*s < 33) || (*s > 126))
2362 *msgptr = string_sprintf("Invalid character in header \"%.*s\" found",
2363 colon - h->text, h->text);
2370 /*************************************************
2371 * Check for blind recipients *
2372 *************************************************/
2374 /* This function checks that every (envelope) recipient is mentioned in either
2375 the To: or Cc: header lines, thus detecting blind carbon copies.
2377 There are two ways of scanning that could be used: either scan the header lines
2378 and tick off the recipients, or scan the recipients and check the header lines.
2379 The original proposed patch did the former, but I have chosen to do the latter,
2380 because (a) it requires no memory and (b) will use fewer resources when there
2381 are many addresses in To: and/or Cc: and only one or two envelope recipients.
2384 Returns: OK if there are no blind recipients
2385 FAIL if there is at least one blind recipient
2389 verify_check_notblind(void)
2392 for (i = 0; i < recipients_count; i++)
2396 uschar *address = recipients_list[i].address;
2398 for (h = header_list; !found && h != NULL; h = h->next)
2402 if (h->type != htype_to && h->type != htype_cc) continue;
2404 colon = Ustrchr(h->text, ':');
2406 while (isspace(*s)) s++;
2408 /* Loop for multiple addresses in the header, enabling group syntax. Note
2409 that we have to reset this after the header has been scanned. */
2411 parse_allow_group = TRUE;
2415 uschar *ss = parse_find_address_end(s, FALSE);
2416 uschar *recipient,*errmess;
2417 int terminator = *ss;
2418 int start, end, domain;
2420 /* Temporarily terminate the string at this point, and extract the
2421 operative address within, allowing group syntax. */
2424 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2427 /* If we found a valid recipient that has a domain, compare it with the
2428 envelope recipient. Local parts are compared case-sensitively, domains
2429 case-insensitively. By comparing from the start with length "domain", we
2430 include the "@" at the end, which ensures that we are comparing the whole
2431 local part of each address. */
2433 if (recipient != NULL && domain != 0)
2435 found = Ustrncmp(recipient, address, domain) == 0 &&
2436 strcmpic(recipient + domain, address + domain) == 0;
2440 /* Advance to the next address */
2442 s = ss + (terminator? 1:0);
2443 while (isspace(*s)) s++;
2444 } /* Next address */
2446 parse_allow_group = FALSE;
2447 parse_found_group = FALSE;
2448 } /* Next header (if found is false) */
2450 if (!found) return FAIL;
2451 } /* Next recipient */
2458 /*************************************************
2459 * Find if verified sender *
2460 *************************************************/
2462 /* Usually, just a single address is verified as the sender of the message.
2463 However, Exim can be made to verify other addresses as well (often related in
2464 some way), and this is useful in some environments. There may therefore be a
2465 chain of such addresses that have previously been tested. This function finds
2466 whether a given address is on the chain.
2468 Arguments: the address to be verified
2469 Returns: pointer to an address item, or NULL
2473 verify_checked_sender(uschar *sender)
2476 for (addr = sender_verified_list; addr != NULL; addr = addr->next)
2477 if (Ustrcmp(sender, addr->address) == 0) break;
2485 /*************************************************
2486 * Get valid header address *
2487 *************************************************/
2489 /* Scan the originator headers of the message, looking for an address that
2490 verifies successfully. RFC 822 says:
2492 o The "Sender" field mailbox should be sent notices of
2493 any problems in transport or delivery of the original
2494 messages. If there is no "Sender" field, then the
2495 "From" field mailbox should be used.
2497 o If the "Reply-To" field exists, then the reply should
2498 go to the addresses indicated in that field and not to
2499 the address(es) indicated in the "From" field.
2501 So we check a Sender field if there is one, else a Reply_to field, else a From
2502 field. As some strange messages may have more than one of these fields,
2503 especially if they are resent- fields, check all of them if there is more than
2507 user_msgptr points to where to put a user error message
2508 log_msgptr points to where to put a log error message
2509 callout timeout for callout check (passed to verify_address())
2510 callout_overall overall callout timeout (ditto)
2511 callout_connect connect callout timeout (ditto)
2512 se_mailfrom mailfrom for verify; NULL => ""
2513 pm_mailfrom sender for pm callout check (passed to verify_address())
2514 options callout options (passed to verify_address())
2515 verrno where to put the address basic_errno
2517 If log_msgptr is set to something without setting user_msgptr, the caller
2518 normally uses log_msgptr for both things.
2520 Returns: result of the verification attempt: OK, FAIL, or DEFER;
2521 FAIL is given if no appropriate headers are found
2525 verify_check_header_address(uschar **user_msgptr, uschar **log_msgptr,
2526 int callout, int callout_overall, int callout_connect, uschar *se_mailfrom,
2527 uschar *pm_mailfrom, int options, int *verrno)
2529 static int header_types[] = { htype_sender, htype_reply_to, htype_from };
2534 for (i = 0; i < 3 && !done; i++)
2537 for (h = header_list; h != NULL && !done; h = h->next)
2539 int terminator, new_ok;
2540 uschar *s, *ss, *endname;
2542 if (h->type != header_types[i]) continue;
2543 s = endname = Ustrchr(h->text, ':') + 1;
2545 /* Scan the addresses in the header, enabling group syntax. Note that we
2546 have to reset this after the header has been scanned. */
2548 parse_allow_group = TRUE;
2552 address_item *vaddr;
2554 while (isspace(*s) || *s == ',') s++;
2555 if (*s == 0) break; /* End of header */
2557 ss = parse_find_address_end(s, FALSE);
2559 /* The terminator is a comma or end of header, but there may be white
2560 space preceding it (including newline for the last address). Move back
2561 past any white space so we can check against any cached envelope sender
2562 address verifications. */
2564 while (isspace(ss[-1])) ss--;
2568 HDEBUG(D_verify) debug_printf("verifying %.*s header address %s\n",
2569 (int)(endname - h->text), h->text, s);
2571 /* See if we have already verified this address as an envelope sender,
2572 and if so, use the previous answer. */
2574 vaddr = verify_checked_sender(s);
2576 if (vaddr != NULL && /* Previously checked */
2577 (callout <= 0 || /* No callout needed; OR */
2578 vaddr->special_action > 256)) /* Callout was done */
2580 new_ok = vaddr->special_action & 255;
2581 HDEBUG(D_verify) debug_printf("previously checked as envelope sender\n");
2582 *ss = terminator; /* Restore shortened string */
2585 /* Otherwise we run the verification now. We must restore the shortened
2586 string before running the verification, so the headers are correct, in
2587 case there is any rewriting. */
2591 int start, end, domain;
2592 uschar *address = parse_extract_address(s, log_msgptr, &start, &end,
2597 /* If we found an empty address, just carry on with the next one, but
2598 kill the message. */
2600 if (address == NULL && Ustrcmp(*log_msgptr, "empty address") == 0)
2607 /* If verification failed because of a syntax error, fail this
2608 function, and ensure that the failing address gets added to the error
2611 if (address == NULL)
2614 while (ss > s && isspace(ss[-1])) ss--;
2615 *log_msgptr = string_sprintf("syntax error in '%.*s' header when "
2616 "scanning for sender: %s in \"%.*s\"",
2617 (int)(endname - h->text), h->text, *log_msgptr, (int)(ss - s), s);
2623 /* Else go ahead with the sender verification. But it isn't *the*
2624 sender of the message, so set vopt_fake_sender to stop sender_address
2625 being replaced after rewriting or qualification. */
2629 vaddr = deliver_make_addr(address, FALSE);
2630 new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender,
2631 callout, callout_overall, callout_connect, se_mailfrom,
2636 /* We now have the result, either newly found, or cached. If we are
2637 giving out error details, set a specific user error. This means that the
2638 last of these will be returned to the user if all three fail. We do not
2639 set a log message - the generic one below will be used. */
2643 *verrno = vaddr->basic_errno;
2644 if (smtp_return_error_details)
2645 *user_msgptr = string_sprintf("Rejected after DATA: "
2646 "could not verify \"%.*s\" header address\n%s: %s",
2647 (int)(endname - h->text), h->text, vaddr->address, vaddr->message);
2650 /* Success or defer */
2659 if (new_ok == DEFER) yield = DEFER;
2661 /* Move on to any more addresses in the header */
2664 } /* Next address */
2666 parse_allow_group = FALSE;
2667 parse_found_group = FALSE;
2668 } /* Next header, unless done */
2669 } /* Next header type unless done */
2671 if (yield == FAIL && *log_msgptr == NULL)
2672 *log_msgptr = US"there is no valid sender in any header line";
2674 if (yield == DEFER && *log_msgptr == NULL)
2675 *log_msgptr = US"all attempts to verify a sender in a header line deferred";
2683 /*************************************************
2684 * Get RFC 1413 identification *
2685 *************************************************/
2687 /* Attempt to get an id from the sending machine via the RFC 1413 protocol. If
2688 the timeout is set to zero, then the query is not done. There may also be lists
2689 of hosts and nets which are exempt. To guard against malefactors sending
2690 non-printing characters which could, for example, disrupt a message's headers,
2691 make sure the string consists of printing characters only.
2694 port the port to connect to; usually this is IDENT_PORT (113), but when
2695 running in the test harness with -bh a different value is used.
2699 Side effect: any received ident value is put in sender_ident (NULL otherwise)
2703 verify_get_ident(int port)
2705 client_conn_ctx ident_conn_ctx = {0};
2707 int received_sender_port, received_interface_port, n;
2710 uschar buffer[2048];
2712 /* Default is no ident. Check whether we want to do an ident check for this
2715 sender_ident = NULL;
2716 if (rfc1413_query_timeout <= 0 || verify_check_host(&rfc1413_hosts) != OK)
2719 DEBUG(D_ident) debug_printf("doing ident callback\n");
2721 /* Set up a connection to the ident port of the remote host. Bind the local end
2722 to the incoming interface address. If the sender host address is an IPv6
2723 address, the incoming interface address will also be IPv6. */
2725 host_af = Ustrchr(sender_host_address, ':') == NULL ? AF_INET : AF_INET6;
2726 if ((ident_conn_ctx.sock = ip_socket(SOCK_STREAM, host_af)) < 0) return;
2728 if (ip_bind(ident_conn_ctx.sock, host_af, interface_address, 0) < 0)
2730 DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n",
2735 /* Construct and send the query. */
2737 qlen = snprintf(CS buffer, sizeof(buffer), "%d , %d\r\n",
2738 sender_host_port, interface_port);
2739 early_data.data = buffer;
2740 early_data.len = qlen;
2742 if (ip_connect(ident_conn_ctx.sock, host_af, sender_host_address, port,
2743 rfc1413_query_timeout, &early_data) < 0)
2745 if (errno == ETIMEDOUT && LOGGING(ident_timeout))
2746 log_write(0, LOG_MAIN, "ident connection to %s timed out",
2747 sender_host_address);
2749 DEBUG(D_ident) debug_printf("ident connection to %s failed: %s\n",
2750 sender_host_address, strerror(errno));
2754 /* Read a response line. We put it into the rest of the buffer, using several
2755 recv() calls if necessary. */
2763 int size = sizeof(buffer) - (p - buffer);
2765 if (size <= 0) goto END_OFF; /* Buffer filled without seeing \n. */
2766 count = ip_recv(&ident_conn_ctx, p, size, rfc1413_query_timeout);
2767 if (count <= 0) goto END_OFF; /* Read error or EOF */
2769 /* Scan what we just read, to see if we have reached the terminating \r\n. Be
2770 generous, and accept a plain \n terminator as well. The only illegal
2773 for (pp = p; pp < p + count; pp++)
2775 if (*pp == 0) goto END_OFF; /* Zero octet not allowed */
2778 if (pp[-1] == '\r') pp--;
2780 goto GOT_DATA; /* Break out of both loops */
2784 /* Reached the end of the data without finding \n. Let the loop continue to
2785 read some more, if there is room. */
2792 /* We have received a line of data. Check it carefully. It must start with the
2793 same two port numbers that we sent, followed by data as defined by the RFC. For
2796 12345 , 25 : USERID : UNIX :root
2798 However, the amount of white space may be different to what we sent. In the
2799 "osname" field there may be several sub-fields, comma separated. The data we
2800 actually want to save follows the third colon. Some systems put leading spaces
2801 in it - we discard those. */
2803 if (sscanf(CS buffer + qlen, "%d , %d%n", &received_sender_port,
2804 &received_interface_port, &n) != 2 ||
2805 received_sender_port != sender_host_port ||
2806 received_interface_port != interface_port)
2809 p = buffer + qlen + n;
2810 while(isspace(*p)) p++;
2811 if (*p++ != ':') goto END_OFF;
2812 while(isspace(*p)) p++;
2813 if (Ustrncmp(p, "USERID", 6) != 0) goto END_OFF;
2815 while(isspace(*p)) p++;
2816 if (*p++ != ':') goto END_OFF;
2817 while (*p != 0 && *p != ':') p++;
2818 if (*p++ == 0) goto END_OFF;
2819 while(isspace(*p)) p++;
2820 if (*p == 0) goto END_OFF;
2822 /* The rest of the line is the data we want. We turn it into printing
2823 characters when we save it, so that it cannot mess up the format of any logging
2824 or Received: lines into which it gets inserted. We keep a maximum of 127
2825 characters. The deconst cast is ok as we fed a nonconst to string_printing() */
2827 sender_ident = US string_printing(string_copyn(p, 127));
2828 DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident);
2831 (void)close(ident_conn_ctx.sock);
2838 /*************************************************
2839 * Match host to a single host-list item *
2840 *************************************************/
2842 /* This function compares a host (name or address) against a single item
2843 from a host list. The host name gets looked up if it is needed and is not
2844 already known. The function is called from verify_check_this_host() via
2845 match_check_list(), which is why most of its arguments are in a single block.
2848 arg the argument block (see below)
2849 ss the host-list item
2850 valueptr where to pass back looked up data, or NULL
2851 error for error message when returning ERROR
2854 host_name (a) the host name, or
2855 (b) NULL, implying use sender_host_name and
2856 sender_host_aliases, looking them up if required, or
2857 (c) the empty string, meaning that only IP address matches
2859 host_address the host address
2860 host_ipv4 the IPv4 address taken from an IPv6 one
2864 DEFER lookup deferred
2865 ERROR (a) failed to find the host name or IP address, or
2866 (b) unknown lookup type specified, or
2867 (c) host name encountered when only IP addresses are
2872 check_host(void *arg, const uschar *ss, const uschar **valueptr, uschar **error)
2874 check_host_block *cb = (check_host_block *)arg;
2877 BOOL iplookup = FALSE;
2878 BOOL isquery = FALSE;
2879 BOOL isiponly = cb->host_name != NULL && cb->host_name[0] == 0;
2884 /* Optimize for the special case when the pattern is "*". */
2886 if (*ss == '*' && ss[1] == 0) return OK;
2888 /* If the pattern is empty, it matches only in the case when there is no host -
2889 this can occur in ACL checking for SMTP input using the -bs option. In this
2890 situation, the host address is the empty string. */
2892 if (cb->host_address[0] == 0) return (*ss == 0)? OK : FAIL;
2893 if (*ss == 0) return FAIL;
2895 /* If the pattern is precisely "@" then match against the primary host name,
2896 provided that host name matching is permitted; if it's "@[]" match against the
2897 local host's IP addresses. */
2903 if (isiponly) return ERROR;
2904 ss = primary_hostname;
2906 else if (Ustrcmp(ss, "@[]") == 0)
2908 ip_address_item *ip;
2909 for (ip = host_find_interfaces(); ip != NULL; ip = ip->next)
2910 if (Ustrcmp(ip->address, cb->host_address) == 0) return OK;
2915 /* If the pattern is an IP address, optionally followed by a bitmask count, do
2916 a (possibly masked) comparison with the current IP address. */
2918 if (string_is_ip_address(ss, &maskoffset) != 0)
2919 return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL);
2921 /* The pattern is not an IP address. A common error that people make is to omit
2922 one component of an IPv4 address, either by accident, or believing that, for
2923 example, 1.2.3/24 is the same as 1.2.3.0/24, or 1.2.3 is the same as 1.2.3.0,
2924 which it isn't. (Those applications that do accept 1.2.3 as an IP address
2925 interpret it as 1.2.0.3 because the final component becomes 16-bit - this is an
2926 ancient specification.) To aid in debugging these cases, we give a specific
2927 error if the pattern contains only digits and dots or contains a slash preceded
2928 only by digits and dots (a slash at the start indicates a file name and of
2929 course slashes may be present in lookups, but not preceded only by digits and
2932 for (t = ss; isdigit(*t) || *t == '.'; t++);
2933 if (*t == 0 || (*t == '/' && t != ss))
2935 *error = US"malformed IPv4 address or address mask";
2939 /* See if there is a semicolon in the pattern */
2941 semicolon = Ustrchr(ss, ';');
2943 /* If we are doing an IP address only match, then all lookups must be IP
2944 address lookups, even if there is no "net-". */
2948 iplookup = semicolon != NULL;
2951 /* Otherwise, if the item is of the form net[n]-lookup;<file|query> then it is
2952 a lookup on a masked IP network, in textual form. We obey this code even if we
2953 have already set iplookup, so as to skip over the "net-" prefix and to set the
2954 mask length. The net- stuff really only applies to single-key lookups where the
2955 key is implicit. For query-style lookups the key is specified in the query.
2956 From release 4.30, the use of net- for query style is no longer needed, but we
2957 retain it for backward compatibility. */
2959 if (Ustrncmp(ss, "net", 3) == 0 && semicolon != NULL)
2962 for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0';
2963 if (mlen == 0 && t == ss+3) mlen = -1; /* No mask supplied */
2964 iplookup = (*t++ == '-');
2968 /* Do the IP address lookup if that is indeed what we have */
2976 uschar *filename, *key, *result;
2979 /* Find the search type */
2981 search_type = search_findtype(t, semicolon - t);
2983 if (search_type < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
2984 search_error_message);
2986 /* Adjust parameters for the type of lookup. For a query-style lookup, there
2987 is no file name, and the "key" is just the query. For query-style with a file
2988 name, we have to fish the file off the start of the query. For a single-key
2989 lookup, the key is the current IP address, masked appropriately, and
2990 reconverted to text form, with the mask appended. For IPv6 addresses, specify
2991 dot separators instead of colons, except when the lookup type is "iplsearch".
2994 if (mac_islookup(search_type, lookup_absfilequery))
2996 filename = semicolon + 1;
2998 while (*key != 0 && !isspace(*key)) key++;
2999 filename = string_copyn(filename, key - filename);
3000 while (isspace(*key)) key++;
3002 else if (mac_islookup(search_type, lookup_querystyle))
3005 key = semicolon + 1;
3007 else /* Single-key style */
3009 int sep = (Ustrcmp(lookup_list[search_type]->name, "iplsearch") == 0)?
3011 insize = host_aton(cb->host_address, incoming);
3012 host_mask(insize, incoming, mlen);
3013 (void)host_nmtoa(insize, incoming, mlen, buffer, sep);
3015 filename = semicolon + 1;
3018 /* Now do the actual lookup; note that there is no search_close() because
3019 of the caching arrangements. */
3021 if (!(handle = search_open(filename, search_type, 0, NULL, NULL)))
3022 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s", search_error_message);
3024 result = search_find(handle, filename, key, -1, NULL, 0, 0, NULL);
3025 if (valueptr != NULL) *valueptr = result;
3026 return (result != NULL)? OK : search_find_defer? DEFER: FAIL;
3029 /* The pattern is not an IP address or network reference of any kind. That is,
3030 it is a host name pattern. If this is an IP only match, there's an error in the
3035 *error = US"cannot match host name in match_ip list";
3039 /* Check the characters of the pattern to see if they comprise only letters,
3040 digits, full stops, and hyphens (the constituents of domain names). Allow
3041 underscores, as they are all too commonly found. Sigh. Also, if
3042 allow_utf8_domains is set, allow top-bit characters. */
3044 for (t = ss; *t != 0; t++)
3045 if (!isalnum(*t) && *t != '.' && *t != '-' && *t != '_' &&
3046 (!allow_utf8_domains || *t < 128)) break;
3048 /* If the pattern is a complete domain name, with no fancy characters, look up
3049 its IP address and match against that. Note that a multi-homed host will add
3050 items to the chain. */
3061 /* Using byname rather than bydns here means we cannot determine dnssec
3062 status. On the other hand it is unclear how that could be either
3063 propagated up or enforced. */
3065 rc = host_find_byname(&h, NULL, HOST_FIND_QUALIFY_SINGLE, NULL, FALSE);
3066 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3069 for (hh = &h; hh != NULL; hh = hh->next)
3071 if (host_is_in_net(hh->address, cb->host_address, 0)) return OK;
3075 if (rc == HOST_FIND_AGAIN) return DEFER;
3076 *error = string_sprintf("failed to find IP address for %s", ss);
3080 /* Almost all subsequent comparisons require the host name, and can be done
3081 using the general string matching function. When this function is called for
3082 outgoing hosts, the name is always given explicitly. If it is NULL, it means we
3083 must use sender_host_name and its aliases, looking them up if necessary. */
3085 if (cb->host_name != NULL) /* Explicit host name given */
3086 return match_check_string(cb->host_name, ss, -1, TRUE, TRUE, TRUE,
3089 /* Host name not given; in principle we need the sender host name and its
3090 aliases. However, for query-style lookups, we do not need the name if the
3091 query does not contain $sender_host_name. From release 4.23, a reference to
3092 $sender_host_name causes it to be looked up, so we don't need to do the lookup
3095 if ((semicolon = Ustrchr(ss, ';')) != NULL)
3097 const uschar *affix;
3098 int partial, affixlen, starflags, id;
3101 id = search_findtype_partial(ss, &partial, &affix, &affixlen, &starflags);
3104 if (id < 0) /* Unknown lookup type */
3106 log_write(0, LOG_MAIN|LOG_PANIC, "%s in host list item \"%s\"",
3107 search_error_message, ss);
3110 isquery = mac_islookup(id, lookup_querystyle|lookup_absfilequery);
3115 switch(match_check_string(US"", ss, -1, TRUE, TRUE, TRUE, valueptr))
3118 case DEFER: return DEFER;
3119 default: return FAIL;
3123 /* Not a query-style lookup; must ensure the host name is present, and then we
3124 do a check on the name and all its aliases. */
3126 if (!sender_host_name)
3128 HDEBUG(D_host_lookup)
3129 debug_printf("sender host name required, to match against %s\n", ss);
3130 if (host_lookup_failed || host_name_lookup() != OK)
3132 *error = string_sprintf("failed to find host name for %s",
3133 sender_host_address);;
3136 host_build_sender_fullhost();
3139 /* Match on the sender host name, using the general matching function */
3141 switch(match_check_string(sender_host_name, ss, -1, TRUE, TRUE, TRUE, valueptr))
3144 case DEFER: return DEFER;
3147 /* If there are aliases, try matching on them. */
3149 aliases = sender_host_aliases;
3151 switch(match_check_string(*aliases++, ss, -1, TRUE, TRUE, TRUE, valueptr))
3154 case DEFER: return DEFER;
3162 /*************************************************
3163 * Check a specific host matches a host list *
3164 *************************************************/
3166 /* This function is passed a host list containing items in a number of
3167 different formats and the identity of a host. Its job is to determine whether
3168 the given host is in the set of hosts defined by the list. The host name is
3169 passed as a pointer so that it can be looked up if needed and not already
3170 known. This is commonly the case when called from verify_check_host() to check
3171 an incoming connection. When called from elsewhere the host name should usually
3174 This function is now just a front end to match_check_list(), which runs common
3175 code for scanning a list. We pass it the check_host() function to perform a
3179 listptr pointer to the host list
3180 cache_bits pointer to cache for named lists, or NULL
3181 host_name the host name or NULL, implying use sender_host_name and
3182 sender_host_aliases, looking them up if required
3183 host_address the IP address
3184 valueptr if not NULL, data from a lookup is passed back here
3186 Returns: OK if the host is in the defined set
3187 FAIL if the host is not in the defined set,
3188 DEFER if a data lookup deferred (not a host lookup)
3190 If the host name was needed in order to make a comparison, and could not be
3191 determined from the IP address, the result is FAIL unless the item
3192 "+allow_unknown" was met earlier in the list, in which case OK is returned. */
3195 verify_check_this_host(const uschar **listptr, unsigned int *cache_bits,
3196 const uschar *host_name, const uschar *host_address, const uschar **valueptr)
3199 unsigned int *local_cache_bits = cache_bits;
3200 const uschar *save_host_address = deliver_host_address;
3201 check_host_block cb = { .host_name = host_name, .host_address = host_address };
3203 if (valueptr) *valueptr = NULL;
3205 /* If the host address starts off ::ffff: it is an IPv6 address in
3206 IPv4-compatible mode. Find the IPv4 part for checking against IPv4
3209 cb.host_ipv4 = Ustrncmp(host_address, "::ffff:", 7) == 0
3210 ? host_address + 7 : host_address;
3212 /* During the running of the check, put the IP address into $host_address. In
3213 the case of calls from the smtp transport, it will already be there. However,
3214 in other calls (e.g. when testing ignore_target_hosts), it won't. Just to be on
3215 the safe side, any existing setting is preserved, though as I write this
3216 (November 2004) I can't see any cases where it is actually needed. */
3218 deliver_host_address = host_address;
3219 rc = match_check_list(
3220 listptr, /* the list */
3221 0, /* separator character */
3222 &hostlist_anchor, /* anchor pointer */
3223 &local_cache_bits, /* cache pointer */
3224 check_host, /* function for testing */
3225 &cb, /* argument for function */
3226 MCL_HOST, /* type of check */
3227 (host_address == sender_host_address)?
3228 US"host" : host_address, /* text for debugging */
3229 valueptr); /* where to pass back data */
3230 deliver_host_address = save_host_address;
3237 /*************************************************
3238 * Check the given host item matches a list *
3239 *************************************************/
3241 verify_check_given_host(uschar **listptr, host_item *host)
3243 return verify_check_this_host(CUSS listptr, NULL, host->name, host->address, NULL);
3246 /*************************************************
3247 * Check the remote host matches a list *
3248 *************************************************/
3250 /* This is a front end to verify_check_this_host(), created because checking
3251 the remote host is a common occurrence. With luck, a good compiler will spot
3252 the tail recursion and optimize it. If there's no host address, this is
3253 command-line SMTP input - check against an empty string for the address.
3256 listptr pointer to the host list
3258 Returns: the yield of verify_check_this_host(),
3259 i.e. OK, FAIL, or DEFER
3263 verify_check_host(uschar **listptr)
3265 return verify_check_this_host(CUSS listptr, sender_host_cache, NULL,
3266 (sender_host_address == NULL)? US"" : sender_host_address, NULL);
3273 /*************************************************
3274 * Invert an IP address *
3275 *************************************************/
3277 /* Originally just used for DNS xBL lists, now also used for the
3278 reverse_ip expansion operator.
3281 buffer where to put the answer
3282 address the address to invert
3286 invert_address(uschar *buffer, uschar *address)
3289 uschar *bptr = buffer;
3291 /* If this is an IPv4 address mapped into IPv6 format, adjust the pointer
3292 to the IPv4 part only. */
3294 if (Ustrncmp(address, "::ffff:", 7) == 0) address += 7;
3296 /* Handle IPv4 address: when HAVE_IPV6 is false, the result of host_aton() is
3299 if (host_aton(address, bin) == 1)
3303 for (i = 0; i < 4; i++)
3305 sprintf(CS bptr, "%d.", x & 255);
3306 while (*bptr) bptr++;
3311 /* Handle IPv6 address. Actually, as far as I know, there are no IPv6 addresses
3312 in any DNS black lists, and the format in which they will be looked up is
3313 unknown. This is just a guess. */
3319 for (j = 3; j >= 0; j--)
3322 for (i = 0; i < 8; i++)
3324 sprintf(CS bptr, "%x.", x & 15);
3325 while (*bptr) bptr++;
3332 /* Remove trailing period -- this is needed so that both arbitrary
3333 dnsbl keydomains and inverted addresses may be combined with the
3334 same format string, "%s.%s" */
3341 /*************************************************
3342 * Perform a single dnsbl lookup *
3343 *************************************************/
3345 /* This function is called from verify_check_dnsbl() below. It is also called
3346 recursively from within itself when domain and domain_txt are different
3347 pointers, in order to get the TXT record from the alternate domain.
3350 domain the outer dnsbl domain
3351 domain_txt alternate domain to lookup TXT record on success; when the
3352 same domain is to be used, domain_txt == domain (that is,
3353 the pointers must be identical, not just the text)
3354 keydomain the current keydomain (for debug message)
3355 prepend subdomain to lookup (like keydomain, but
3356 reversed if IP address)
3357 iplist the list of matching IP addresses, or NULL for "any"
3358 bitmask true if bitmask matching is wanted
3359 match_type condition for 'succeed' result
3360 0 => Any RR in iplist (=)
3361 1 => No RR in iplist (!=)
3362 2 => All RRs in iplist (==)
3363 3 => Some RRs not in iplist (!==)
3364 the two bits are defined as MT_NOT and MT_ALL
3365 defer_return what to return for a defer
3367 Returns: OK if lookup succeeded
3372 one_check_dnsbl(uschar *domain, uschar *domain_txt, uschar *keydomain,
3373 uschar *prepend, uschar *iplist, BOOL bitmask, int match_type,
3379 dnsbl_cache_block *cb;
3380 int old_pool = store_pool;
3381 uschar query[256]; /* DNS domain max length */
3383 /* Construct the specific query domainname */
3385 if (!string_format(query, sizeof(query), "%s.%s", prepend, domain))
3387 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
3388 "(ignored): %s...", query);
3392 /* Look for this query in the cache. */
3394 if ( (t = tree_search(dnsbl_cache, query))
3395 && (cb = t->data.ptr)->expiry > time(NULL)
3398 /* Previous lookup was cached */
3401 HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
3404 /* If not cached from a previous lookup, we must do a DNS lookup, and
3405 cache the result in permanent memory. */
3411 store_pool = POOL_PERM;
3415 HDEBUG(D_dnsbl) debug_printf("cached data found but past valid time; ");
3419 { /* Set up a tree entry to cache the lookup */
3420 t = store_get(sizeof(tree_node) + Ustrlen(query));
3421 Ustrcpy(t->name, query);
3422 t->data.ptr = cb = store_get(sizeof(dnsbl_cache_block));
3423 (void)tree_insertnode(&dnsbl_cache, t);
3426 /* Do the DNS lookup . */
3428 HDEBUG(D_dnsbl) debug_printf("new DNS lookup for %s\n", query);
3429 cb->rc = dns_basic_lookup(&dnsa, query, T_A);
3430 cb->text_set = FALSE;
3434 /* If the lookup succeeded, cache the RHS address. The code allows for
3435 more than one address - this was for complete generality and the possible
3436 use of A6 records. However, A6 records are no longer supported. Leave the code
3439 Quite apart from one A6 RR generating multiple addresses, there are DNS
3440 lists that return more than one A record, so we must handle multiple
3441 addresses generated in that way as well.
3443 Mark the cache entry with the "now" plus the minimum of the address TTLs,
3444 or some suitably far-future time if none were found. */
3446 if (cb->rc == DNS_SUCCEED)
3449 dns_address **addrp = &(cb->rhs);
3450 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
3452 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3453 if (rr->type == T_A)
3455 dns_address *da = dns_address_from_rr(&dnsa, rr);
3459 while (da->next) da = da->next;
3461 if (ttl > rr->ttl) ttl = rr->ttl;
3465 /* If we didn't find any A records, change the return code. This can
3466 happen when there is a CNAME record but there are no A records for what
3469 if (!cb->rhs) cb->rc = DNS_NODATA;
3472 cb->expiry = time(NULL)+ttl;
3473 store_pool = old_pool;
3476 /* We now have the result of the DNS lookup, either newly done, or cached
3477 from a previous call. If the lookup succeeded, check against the address
3478 list if there is one. This may be a positive equality list (introduced by
3479 "="), a negative equality list (introduced by "!="), a positive bitmask
3480 list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/
3482 if (cb->rc == DNS_SUCCEED)
3484 dns_address *da = NULL;
3485 uschar *addlist = cb->rhs->address;
3487 /* For A and AAAA records, there may be multiple addresses from multiple
3488 records. For A6 records (currently not expected to be used) there may be
3489 multiple addresses from a single record. */
3491 for (da = cb->rhs->next; da; da = da->next)
3492 addlist = string_sprintf("%s, %s", addlist, da->address);
3494 HDEBUG(D_dnsbl) debug_printf("DNS lookup for %s succeeded (yielding %s)\n",
3497 /* Address list check; this can be either for equality, or via a bitmask.
3498 In the latter case, all the bits must match. */
3502 for (da = cb->rhs; da; da = da->next)
3506 const uschar *ptr = iplist;
3509 /* Handle exact matching */
3513 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))))
3514 if (Ustrcmp(CS da->address, ip) == 0)
3518 /* Handle bitmask matching */
3525 /* At present, all known DNS blocking lists use A records, with
3526 IPv4 addresses on the RHS encoding the information they return. I
3527 wonder if this will linger on as the last vestige of IPv4 when IPv6
3528 is ubiquitous? Anyway, for now we use paranoia code to completely
3529 ignore IPv6 addresses. The default mask is 0, which always matches.
3530 We change this only for IPv4 addresses in the list. */
3532 if (host_aton(da->address, address) == 1) mask = address[0];
3534 /* Scan the returned addresses, skipping any that are IPv6 */
3536 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))))
3538 if (host_aton(ip, address) != 1) continue;
3539 if ((address[0] & mask) == address[0]) break;
3545 (a) An IP address in an any ('=') list matched, or
3546 (b) No IP address in an all ('==') list matched
3548 then we're done searching. */
3550 if (((match_type & MT_ALL) != 0) == (res == NULL)) break;
3553 /* If da == NULL, either
3555 (a) No IP address in an any ('=') list matched, or
3556 (b) An IP address in an all ('==') list didn't match
3558 so behave as if the DNSBL lookup had not succeeded, i.e. the host is not on
3561 if ((match_type == MT_NOT || match_type == MT_ALL) != (da == NULL))
3569 res = US"was no match"; break;
3571 res = US"was an exclude match"; break;
3573 res = US"was an IP address that did not match"; break;
3575 res = US"were no IP addresses that did not match"; break;
3577 debug_printf("=> but we are not accepting this block class because\n");
3578 debug_printf("=> there %s for %s%c%s\n",
3580 ((match_type & MT_ALL) == 0)? "" : "=",
3581 bitmask? '&' : '=', iplist);
3587 /* Either there was no IP list, or the record matched, implying that the
3588 domain is on the list. We now want to find a corresponding TXT record. If an
3589 alternate domain is specified for the TXT record, call this function
3590 recursively to look that up; this has the side effect of re-checking that
3591 there is indeed an A record at the alternate domain. */
3593 if (domain_txt != domain)
3594 return one_check_dnsbl(domain_txt, domain_txt, keydomain, prepend, NULL,
3595 FALSE, match_type, defer_return);
3597 /* If there is no alternate domain, look up a TXT record in the main domain
3598 if it has not previously been cached. */
3602 cb->text_set = TRUE;
3603 if (dns_basic_lookup(&dnsa, query, T_TXT) == DNS_SUCCEED)
3606 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
3608 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3609 if (rr->type == T_TXT) break;
3612 int len = (rr->data)[0];
3613 if (len > 511) len = 127;
3614 store_pool = POOL_PERM;
3615 cb->text = string_sprintf("%.*s", len, CUS (rr->data+1));
3616 store_pool = old_pool;
3621 dnslist_value = addlist;
3622 dnslist_text = cb->text;
3626 /* There was a problem with the DNS lookup */
3628 if (cb->rc != DNS_NOMATCH && cb->rc != DNS_NODATA)
3630 log_write(L_dnslist_defer, LOG_MAIN,
3631 "DNS list lookup defer (probably timeout) for %s: %s", query,
3632 (defer_return == OK)? US"assumed in list" :
3633 (defer_return == FAIL)? US"assumed not in list" :
3634 US"returned DEFER");
3635 return defer_return;
3638 /* No entry was found in the DNS; continue for next domain */
3642 debug_printf("DNS lookup for %s failed\n", query);
3643 debug_printf("=> that means %s is not listed at %s\n",
3653 /*************************************************
3654 * Check host against DNS black lists *
3655 *************************************************/
3657 /* This function runs checks against a list of DNS black lists, until one
3658 matches. Each item on the list can be of the form
3660 domain=ip-address/key
3662 The domain is the right-most domain that is used for the query, for example,
3663 blackholes.mail-abuse.org. If the IP address is present, there is a match only
3664 if the DNS lookup returns a matching IP address. Several addresses may be
3665 given, comma-separated, for example: x.y.z=127.0.0.1,127.0.0.2.
3667 If no key is given, what is looked up in the domain is the inverted IP address
3668 of the current client host. If a key is given, it is used to construct the
3669 domain for the lookup. For example:
3671 dsn.rfc-ignorant.org/$sender_address_domain
3673 After finding a match in the DNS, the domain is placed in $dnslist_domain, and
3674 then we check for a TXT record for an error message, and if found, save its
3675 value in $dnslist_text. We also cache everything in a tree, to optimize
3678 The TXT record is normally looked up in the same domain as the A record, but
3679 when many lists are combined in a single DNS domain, this will not be a very
3680 specific message. It is possible to specify a different domain for looking up
3681 TXT records; this is given before the main domain, comma-separated. For
3684 dnslists = http.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.2 : \
3685 socks.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.3
3687 The caching ensures that only one lookup in dnsbl.sorbs.net is done.
3689 Note: an address for testing RBL is 192.203.178.39
3690 Note: an address for testing DUL is 192.203.178.4
3691 Note: a domain for testing RFCI is example.tld.dsn.rfc-ignorant.org
3695 listptr the domain/address/data list
3696 log_msgptr log message on error
3698 Returns: OK successful lookup (i.e. the address is on the list), or
3699 lookup deferred after +include_unknown
3700 FAIL name not found, or no data found for the given type, or
3701 lookup deferred after +exclude_unknown (default)
3702 DEFER lookup failure, if +defer_unknown was set
3706 verify_check_dnsbl(int where, const uschar ** listptr, uschar ** log_msgptr)
3709 int defer_return = FAIL;
3710 const uschar *list = *listptr;
3713 uschar buffer[1024];
3714 uschar revadd[128]; /* Long enough for IPv6 address */
3716 /* Indicate that the inverted IP address is not yet set up */
3720 /* In case this is the first time the DNS resolver is being used. */
3722 dns_init(FALSE, FALSE, FALSE); /*XXX dnssec? */
3724 /* Loop through all the domains supplied, until something matches */
3726 while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
3729 BOOL bitmask = FALSE;
3736 HDEBUG(D_dnsbl) debug_printf("DNS list check: %s\n", domain);
3738 /* Deal with special values that change the behaviour on defer */
3740 if (domain[0] == '+')
3742 if (strcmpic(domain, US"+include_unknown") == 0) defer_return = OK;
3743 else if (strcmpic(domain, US"+exclude_unknown") == 0) defer_return = FAIL;
3744 else if (strcmpic(domain, US"+defer_unknown") == 0) defer_return = DEFER;
3746 log_write(0, LOG_MAIN|LOG_PANIC, "unknown item in dnslist (ignored): %s",
3751 /* See if there's explicit data to be looked up */
3753 if ((key = Ustrchr(domain, '/'))) *key++ = 0;
3755 /* See if there's a list of addresses supplied after the domain name. This is
3756 introduced by an = or a & character; if preceded by = we require all matches
3757 and if preceded by ! we invert the result. */
3759 if (!(iplist = Ustrchr(domain, '=')))
3762 iplist = Ustrchr(domain, '&');
3765 if (iplist) /* Found either = or & */
3767 if (iplist > domain && iplist[-1] == '!') /* Handle preceding ! */
3769 match_type |= MT_NOT;
3773 *iplist++ = 0; /* Terminate domain, move on */
3775 /* If we found = (bitmask == FALSE), check for == or =& */
3777 if (!bitmask && (*iplist == '=' || *iplist == '&'))
3779 bitmask = *iplist++ == '&';
3780 match_type |= MT_ALL;
3785 /* If there is a comma in the domain, it indicates that a second domain for
3786 looking up TXT records is provided, before the main domain. Otherwise we must
3787 set domain_txt == domain. */
3789 domain_txt = domain;
3790 comma = Ustrchr(domain, ',');
3797 /* Check that what we have left is a sensible domain name. There is no reason
3798 why these domains should in fact use the same syntax as hosts and email
3799 domains, but in practice they seem to. However, there is little point in
3800 actually causing an error here, because that would no doubt hold up incoming
3801 mail. Instead, I'll just log it. */
3803 for (s = domain; *s != 0; s++)
3805 if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_')
3807 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
3808 "strange characters - is this right?", domain);
3813 /* Check the alternate domain if present */
3815 if (domain_txt != domain) for (s = domain_txt; *s != 0; s++)
3817 if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_')
3819 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
3820 "strange characters - is this right?", domain_txt);
3825 /* If there is no key string, construct the query by adding the domain name
3826 onto the inverted host address, and perform a single DNS lookup. */
3830 if (where == ACL_WHERE_NOTSMTP_START || where == ACL_WHERE_NOTSMTP)
3832 *log_msgptr = string_sprintf
3833 ("cannot test auto-keyed dnslists condition in %s ACL",
3834 acl_wherenames[where]);
3837 if (sender_host_address == NULL) return FAIL; /* can never match */
3838 if (revadd[0] == 0) invert_address(revadd, sender_host_address);
3839 rc = one_check_dnsbl(domain, domain_txt, sender_host_address, revadd,
3840 iplist, bitmask, match_type, defer_return);
3843 dnslist_domain = string_copy(domain_txt);
3844 dnslist_matched = string_copy(sender_host_address);
3845 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
3846 sender_host_address, dnslist_domain);
3848 if (rc != FAIL) return rc; /* OK or DEFER */
3851 /* If there is a key string, it can be a list of domains or IP addresses to
3852 be concatenated with the main domain. */
3859 uschar keybuffer[256];
3860 uschar keyrevadd[128];
3862 while ((keydomain = string_nextinlist(CUSS &key, &keysep, keybuffer,
3863 sizeof(keybuffer))) != NULL)
3865 uschar *prepend = keydomain;
3867 if (string_is_ip_address(keydomain, NULL) != 0)
3869 invert_address(keyrevadd, keydomain);
3870 prepend = keyrevadd;
3873 rc = one_check_dnsbl(domain, domain_txt, keydomain, prepend, iplist,
3874 bitmask, match_type, defer_return);
3878 dnslist_domain = string_copy(domain_txt);
3879 dnslist_matched = string_copy(keydomain);
3880 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
3881 keydomain, dnslist_domain);
3885 /* If the lookup deferred, remember this fact. We keep trying the rest
3886 of the list to see if we get a useful result, and if we don't, we return
3887 DEFER at the end. */
3889 if (rc == DEFER) defer = TRUE;
3890 } /* continue with next keystring domain/address */
3892 if (defer) return DEFER;
3894 } /* continue with next dnsdb outer domain */
3901 /* End of verify.c */