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_context ctctx;
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, TRUE)))
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, TRUE)))
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, TRUE);
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)
374 if (addr->transport == cutthrough.addr.transport)
375 for (host_item * host = host_list; host; host = host->next)
376 if (Ustrcmp(host->address, cutthrough.host.address) == 0)
379 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
382 deliver_host = host->name;
383 deliver_host_address = host->address;
384 deliver_host_port = host->port;
385 deliver_domain = addr->domain;
386 transport_name = addr->transport->name;
388 host_af = Ustrchr(host->address, ':') ? AF_INET6 : AF_INET;
390 if ( !smtp_get_interface(tf->interface, host_af, addr, &interface,
392 || !smtp_get_port(tf->port, addr, &port, US"callout")
394 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
397 smtp_port_for_connect(host, port);
399 if ( ( interface == cutthrough.interface
401 && cutthrough.interface
402 && Ustrcmp(interface, cutthrough.interface) == 0
404 && host->port == cutthrough.host.port
407 uschar * resp = NULL;
409 /* Match! Send the RCPT TO, set done from the response */
411 smtp_write_command(&ctctx, SCMD_FLUSH, "RCPT TO:<%.1000s>\r\n",
412 transport_rcpt_address(addr,
413 addr->transport->rcpt_include_affixes)) >= 0
414 && cutthrough_response(&cutthrough.cctx, '2', &resp,
415 CUTTHROUGH_DATA_TIMEOUT) == '2';
417 /* This would go horribly wrong if a callout fail was ignored by ACL.
418 We punt by abandoning cutthrough on a reject, like the
423 address_item * na = store_get(sizeof(address_item));
424 *na = cutthrough.addr;
425 cutthrough.addr = *addr;
426 cutthrough.addr.host_used = &cutthrough.host;
427 cutthrough.addr.next = na;
433 cancel_cutthrough_connection(TRUE, US"recipient rejected");
434 if (!resp || errno == ETIMEDOUT)
436 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
441 Ustrcpy(resp, US"connection dropped");
444 string_sprintf("response to \"%s\" was: %s",
445 big_buffer, string_printing(resp));
448 string_sprintf("Callout verification failed:\n%s", resp);
450 /* Hard rejection ends the process */
452 if (resp[0] == '5') /* Address rejected */
460 break; /* host_list */
463 cancel_cutthrough_connection(TRUE, US"incompatible connection");
468 /*************************************************
469 * Do callout verification for an address *
470 *************************************************/
472 /* This function is called from verify_address() when the address has routed to
473 a host list, and a callout has been requested. Callouts are expensive; that is
474 why a cache is used to improve the efficiency.
477 addr the address that's been routed
478 host_list the list of hosts to try
479 tf the transport feedback block
481 ifstring "interface" option from transport, or NULL
482 portstring "port" option from transport, or NULL
483 protocolstring "protocol" option from transport, or NULL
484 callout the per-command callout timeout
485 callout_overall the overall callout timeout (if < 0 use 4*callout)
486 callout_connect the callout connection timeout (if < 0 use callout)
487 options the verification options - these bits are used:
488 vopt_is_recipient => this is a recipient address
489 vopt_callout_no_cache => don't use callout cache
490 vopt_callout_fullpm => if postmaster check, do full one
491 vopt_callout_random => do the "random" thing
492 vopt_callout_recipsender => use real sender for recipient
493 vopt_callout_recippmaster => use postmaster for recipient
494 vopt_callout_hold => lazy close connection
495 se_mailfrom MAIL FROM address for sender verify; NULL => ""
496 pm_mailfrom if non-NULL, do the postmaster check with this sender
498 Returns: OK/FAIL/DEFER
502 do_callout(address_item *addr, host_item *host_list, transport_feedback *tf,
503 int callout, int callout_overall, int callout_connect, int options,
504 uschar *se_mailfrom, uschar *pm_mailfrom)
507 int old_domain_cache_result = ccache_accept;
510 uschar *from_address;
511 uschar *random_local_part = NULL;
512 const uschar *save_deliver_domain = deliver_domain;
513 uschar **failure_ptr = options & vopt_is_recipient
514 ? &recipient_verify_failure : &sender_verify_failure;
515 dbdata_callout_cache new_domain_record;
516 dbdata_callout_cache_address new_address_record;
517 time_t callout_start_time;
519 new_domain_record.result = ccache_unknown;
520 new_domain_record.postmaster_result = ccache_unknown;
521 new_domain_record.random_result = ccache_unknown;
523 memset(&new_address_record, 0, sizeof(new_address_record));
525 /* For a recipient callout, the key used for the address cache record must
526 include the sender address if we are using the real sender in the callout,
527 because that may influence the result of the callout. */
529 if (options & vopt_is_recipient)
530 if (options & vopt_callout_recipsender)
532 from_address = sender_address;
533 address_key = string_sprintf("%s/<%s>", addr->address, sender_address);
534 if (cutthrough.delivery) options |= vopt_callout_no_cache;
536 else if (options & vopt_callout_recippmaster)
538 from_address = string_sprintf("postmaster@%s", qualify_domain_sender);
539 address_key = string_sprintf("%s/<postmaster@%s>", addr->address,
540 qualify_domain_sender);
545 address_key = addr->address;
548 /* For a sender callout, we must adjust the key if the mailfrom address is not
553 from_address = se_mailfrom ? se_mailfrom : US"";
554 address_key = *from_address
555 ? string_sprintf("%s/<%s>", addr->address, from_address) : addr->address;
558 if (cached_callout_lookup(addr, address_key, from_address,
559 &options, &pm_mailfrom, &yield, failure_ptr,
560 &new_domain_record, &old_domain_cache_result))
562 cancel_cutthrough_connection(TRUE, US"cache-hit");
566 if (!addr->transport)
568 HDEBUG(D_verify) debug_printf("cannot callout via null transport\n");
570 else if (Ustrcmp(addr->transport->driver_name, "smtp") != 0)
571 log_write(0, LOG_MAIN|LOG_PANIC|LOG_CONFIG_FOR, "callout transport '%s': %s is non-smtp",
572 addr->transport->name, addr->transport->driver_name);
575 smtp_transport_options_block *ob =
576 (smtp_transport_options_block *)addr->transport->options_block;
578 /* The information wasn't available in the cache, so we have to do a real
579 callout and save the result in the cache for next time, unless no_cache is set,
580 or unless we have a previously cached negative random result. If we are to test
581 with a random local part, ensure that such a local part is available. If not,
582 log the fact, but carry on without randomising. */
584 if (options & vopt_callout_random && callout_random_local_part)
585 if (!(random_local_part = expand_string(callout_random_local_part)))
586 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand "
587 "callout_random_local_part: %s", expand_string_message);
589 /* Default the connect and overall callout timeouts if not set, and record the
590 time we are starting so that we can enforce it. */
592 if (callout_overall < 0) callout_overall = 4 * callout;
593 if (callout_connect < 0) callout_connect = callout;
594 callout_start_time = time(NULL);
596 /* Before doing a real callout, if this is an SMTP connection, flush the SMTP
597 output because a callout might take some time. When PIPELINING is active and
598 there are many recipients, the total time for doing lots of callouts can add up
599 and cause the client to time out. So in this case we forgo the PIPELINING
602 if (smtp_out && !f.disable_callout_flush) mac_smtp_fflush();
604 clearflag(addr, af_verify_pmfail); /* postmaster callout flag */
605 clearflag(addr, af_verify_nsfail); /* null sender callout flag */
607 /* cutthrough-multi: if a nonfirst rcpt has the same routing as the first,
608 and we are holding a cutthrough conn open, we can just append the rcpt to
609 that conn for verification purposes (and later delivery also). Simplest
610 coding means skipping this whole loop and doing the append separately. */
612 /* Can we re-use an open cutthrough connection? */
613 if ( cutthrough.cctx.sock >= 0
614 && (options & (vopt_callout_recipsender | vopt_callout_recippmaster))
615 == vopt_callout_recipsender
616 && !random_local_part
619 done = cutthrough_multi(addr, host_list, tf, &yield);
621 /* If we did not use a cached connection, make connections to the hosts
622 and do real callouts. The list of hosts is passed in as an argument. */
624 for (host_item * host = host_list; host && !done; host = host->next)
628 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
633 DEBUG(D_verify) debug_printf("no IP address for host name %s: skipping\n",
638 /* Check the overall callout timeout */
640 if (time(NULL) - callout_start_time >= callout_overall)
642 HDEBUG(D_verify) debug_printf("overall timeout for callout exceeded\n");
646 /* Set IPv4 or IPv6 */
648 host_af = Ustrchr(host->address, ':') ? AF_INET6 : AF_INET;
650 /* Expand and interpret the interface and port strings. The latter will not
651 be used if there is a host-specific port (e.g. from a manualroute router).
652 This has to be delayed till now, because they may expand differently for
653 different hosts. If there's a failure, log it, but carry on with the
656 deliver_host = host->name;
657 deliver_host_address = host->address;
658 deliver_host_port = host->port;
659 deliver_domain = addr->domain;
660 transport_name = addr->transport->name;
662 if ( !smtp_get_interface(tf->interface, host_af, addr, &interface,
664 || !smtp_get_port(tf->port, addr, &port, US"callout")
666 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
670 sx.conn_args.host = host;
671 sx.conn_args.host_af = host_af,
673 sx.conn_args.interface = interface;
674 sx.helo_data = tf->helo_data;
675 sx.conn_args.tblock = addr->transport;
678 tls_retry_connection:
679 /* Set the address state so that errors are recorded in it */
681 addr->transport_return = PENDING_DEFER;
682 ob->connect_timeout = callout_connect;
683 ob->command_timeout = callout;
685 /* Get the channel set up ready for a message (MAIL FROM being the next
686 SMTP command to send. If we tried TLS but it failed, try again without
689 yield = smtp_setup_conn(&sx, FALSE);
692 && addr->basic_errno == ERRNO_TLSFAILURE
693 && ob->tls_tempfail_tryclear
694 && verify_check_given_host(CUSS &ob->hosts_require_tls, host) != OK
697 log_write(0, LOG_MAIN,
698 "%s: callout unencrypted to %s [%s] (not in hosts_require_tls)",
699 addr->message, host->name, host->address);
700 addr->transport_return = PENDING_DEFER;
701 yield = smtp_setup_conn(&sx, TRUE);
706 errno = addr->basic_errno;
707 transport_name = NULL;
708 deliver_host = deliver_host_address = NULL;
709 deliver_domain = save_deliver_domain;
711 /* Failure to accept HELO is cached; this blocks the whole domain for all
712 senders. I/O errors and defer responses are not cached. */
714 if (yield == FAIL && (errno == 0 || errno == ERRNO_SMTPCLOSED))
716 setflag(addr, af_verify_nsfail);
717 new_domain_record.result = ccache_reject;
725 /* If we needed to authenticate, smtp_setup_conn() did that. Copy
726 the AUTH info for logging */
728 addr->authenticator = client_authenticator;
729 addr->auth_id = client_authenticated_id;
731 sx.from_addr = from_address;
732 sx.first_addr = sx.sync_addr = addr;
733 sx.ok = FALSE; /*XXX these 3 last might not be needed for verify? */
735 sx.completed_addr = FALSE;
737 new_domain_record.result = old_domain_cache_result == ccache_reject_mfnull
738 ? ccache_reject_mfnull : ccache_accept;
740 /* Do the random local part check first. Temporarily replace the recipient
741 with the "random" value */
743 if (random_local_part)
745 uschar * main_address = addr->address;
746 const uschar * rcpt_domain = addr->domain;
749 uschar * errstr = NULL;
750 if ( testflag(addr, af_utf8_downcvt)
751 && (rcpt_domain = string_domain_utf8_to_alabel(rcpt_domain,
755 addr->message = errstr;
756 errno = ERRNO_EXPANDFAIL;
757 setflag(addr, af_verify_nsfail);
759 rcpt_domain = US""; /*XXX errorhandling! */
763 /* This would be ok for 1st rcpt of a cutthrough (the case handled here;
764 subsequents are done in cutthrough_multi()), but no way to
765 handle a subsequent because of the RSET vaporising the MAIL FROM.
766 So refuse to support any. Most cutthrough use will not involve
767 random_local_part, so no loss. */
768 cancel_cutthrough_connection(TRUE, US"random-recipient");
770 addr->address = string_sprintf("%s@%.1000s",
771 random_local_part, rcpt_domain);
774 /* If accepted, we aren't going to do any further tests below.
775 Otherwise, cache a real negative response, and get back to the right
776 state to send RCPT. Unless there's some problem such as a dropped
777 connection, we expect to succeed, because the commands succeeded above.
778 However, some servers drop the connection after responding to an
779 invalid recipient, so on (any) error we drop and remake the connection.
780 XXX We don't care about that for postmaster_full. Should we?
782 XXX could we add another flag to the context, and have the common
783 code emit the RSET too? Even pipelined after the RCPT...
784 Then the main-verify call could use it if there's to be a subsequent
786 The sync_responses() would need to be taught about it and we'd
787 need another return code filtering out to here.
789 Avoid using a SIZE option on the MAIL for all random-rcpt checks.
792 sx.avoid_option = OPTION_SIZE;
794 /* Remember when we last did a random test */
795 new_domain_record.random_stamp = time(NULL);
797 if (smtp_write_mail_and_rcpt_cmds(&sx, &yield) == 0)
798 switch(addr->transport_return)
800 case PENDING_OK: /* random was accepted, unfortunately */
801 new_domain_record.random_result = ccache_accept;
802 yield = OK; /* Only usable verify result we can return */
804 *failure_ptr = US"random";
806 case FAIL: /* rejected: the preferred result */
807 new_domain_record.random_result = ccache_reject;
810 /* Between each check, issue RSET, because some servers accept only
811 one recipient after MAIL FROM:<>.
812 XXX We don't care about that for postmaster_full. Should we? */
815 smtp_write_command(&sx, SCMD_FLUSH, "RSET\r\n") >= 0 &&
816 smtp_read_response(&sx, sx.buffer, sizeof(sx.buffer), '2', callout)))
820 debug_printf_indent("problem after random/rset/mfrom; reopen conn\n");
821 random_local_part = NULL;
823 tls_close(sx.cctx.tls_ctx, TLS_SHUTDOWN_NOWAIT);
825 HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP(close)>>\n");
826 (void)close(sx.cctx.sock);
828 #ifndef DISABLE_EVENT
829 (void) event_raise(addr->transport->event_action,
830 US"tcp:close", NULL);
832 addr->address = main_address;
833 addr->transport_return = PENDING_DEFER;
834 sx.first_addr = sx.sync_addr = addr;
837 sx.completed_addr = FALSE;
838 goto tls_retry_connection;
839 case DEFER: /* 4xx response to random */
840 break; /* Just to be clear. ccache_unknown, !done. */
843 /* Re-setup for main verify, or for the error message when failing */
844 addr->address = main_address;
845 addr->transport_return = PENDING_DEFER;
846 sx.first_addr = sx.sync_addr = addr;
849 sx.completed_addr = FALSE;
854 /* Main verify. For rcpt-verify use SIZE if we know it and we're not cacheing;
855 for sndr-verify never use it. */
859 if (!(options & vopt_is_recipient && options & vopt_callout_no_cache))
860 sx.avoid_option = OPTION_SIZE;
863 switch(smtp_write_mail_and_rcpt_cmds(&sx, &yield))
865 case 0: switch(addr->transport_return) /* ok so far */
867 case PENDING_OK: done = TRUE;
868 new_address_record.result = ccache_accept;
870 case FAIL: done = TRUE;
872 *failure_ptr = US"recipient";
873 new_address_record.result = ccache_reject;
879 case -1: /* MAIL response error */
880 *failure_ptr = US"mail";
881 if (errno == 0 && sx.buffer[0] == '5')
883 setflag(addr, af_verify_nsfail);
884 if (from_address[0] == 0)
885 new_domain_record.result = ccache_reject_mfnull;
888 /* non-MAIL read i/o error */
889 /* non-MAIL response timeout */
890 /* internal error; channel still usable */
891 default: break; /* transmit failed */
895 addr->auth_sndr = client_authenticated_sender;
897 deliver_host = deliver_host_address = NULL;
898 deliver_domain = save_deliver_domain;
900 /* Do postmaster check if requested; if a full check is required, we
901 check for RCPT TO:<postmaster> (no domain) in accordance with RFC 821. */
903 if (done && pm_mailfrom)
905 /* Could possibly shift before main verify, just above, and be ok
906 for cutthrough. But no way to handle a subsequent rcpt, so just
908 cancel_cutthrough_connection(TRUE, US"postmaster verify");
909 HDEBUG(D_acl|D_v) debug_printf_indent("Cutthrough cancelled by presence of postmaster verify\n");
911 done = smtp_write_command(&sx, SCMD_FLUSH, "RSET\r\n") >= 0
912 && smtp_read_response(&sx, sx.buffer, sizeof(sx.buffer), '2', callout);
916 uschar * main_address = addr->address;
918 /*XXX oops, affixes */
919 addr->address = string_sprintf("postmaster@%.1000s", addr->domain);
920 addr->transport_return = PENDING_DEFER;
922 sx.from_addr = pm_mailfrom;
923 sx.first_addr = sx.sync_addr = addr;
926 sx.completed_addr = FALSE;
927 sx.avoid_option = OPTION_SIZE;
929 if( smtp_write_mail_and_rcpt_cmds(&sx, &yield) == 0
930 && addr->transport_return == PENDING_OK
934 done = (options & vopt_callout_fullpm) != 0
935 && smtp_write_command(&sx, SCMD_FLUSH,
936 "RCPT TO:<postmaster>\r\n") >= 0
937 && smtp_read_response(&sx, sx.buffer,
938 sizeof(sx.buffer), '2', callout);
940 /* Sort out the cache record */
942 new_domain_record.postmaster_stamp = time(NULL);
945 new_domain_record.postmaster_result = ccache_accept;
946 else if (errno == 0 && sx.buffer[0] == '5')
948 *failure_ptr = US"postmaster";
949 setflag(addr, af_verify_pmfail);
950 new_domain_record.postmaster_result = ccache_reject;
953 addr->address = main_address;
956 /* For any failure of the main check, other than a negative response, we just
957 close the connection and carry on. We can identify a negative response by the
958 fact that errno is zero. For I/O errors it will be non-zero
960 Set up different error texts for logging and for sending back to the caller
961 as an SMTP response. Log in all cases, using a one-line format. For sender
962 callouts, give a full response to the caller, but for recipient callouts,
963 don't give the IP address because this may be an internal host whose identity
964 is not to be widely broadcast. */
970 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
971 sx.send_quit = FALSE;
977 extern int acl_where; /* src/acl.c */
979 addr->message = string_sprintf(
980 "response to \"EHLO\" did not include SMTPUTF8");
981 addr->user_message = acl_where == ACL_WHERE_RCPT
982 ? US"533 no support for internationalised mailbox name"
983 : US"550 mailbox unavailable";
990 sx.send_quit = FALSE;
994 if (*sx.buffer == 0) Ustrcpy(sx.buffer, US"connection dropped");
996 /*XXX test here is ugly; seem to have a split of responsibility for
997 building this message. Need to rationalise. Where is it done
998 before here, and when not?
999 Not == 5xx resp to MAIL on main-verify
1001 if (!addr->message) addr->message =
1002 string_sprintf("response to \"%s\" was: %s",
1003 big_buffer, string_printing(sx.buffer));
1005 addr->user_message = options & vopt_is_recipient
1006 ? string_sprintf("Callout verification failed:\n%s", sx.buffer)
1007 : string_sprintf("Called: %s\nSent: %s\nResponse: %s",
1008 host->address, big_buffer, sx.buffer);
1010 /* Hard rejection ends the process */
1012 if (sx.buffer[0] == '5') /* Address rejected */
1020 /* End the SMTP conversation and close the connection. */
1022 /* Cutthrough - on a successful connect and recipient-verify with
1023 use-sender and we are 1st rcpt and have no cutthrough conn so far
1024 here is where we want to leave the conn open. Ditto for a lazy-close
1027 if (cutthrough.delivery)
1029 if (addr->transport->filter_command)
1031 cutthrough.delivery= FALSE;
1032 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of transport filter\n");
1034 #ifndef DISABLE_DKIM
1035 if (ob->dkim.dkim_domain)
1037 cutthrough.delivery= FALSE;
1038 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of DKIM signing\n");
1041 #ifdef EXPERIMENTAL_ARC
1044 cutthrough.delivery= FALSE;
1045 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of ARC signing\n");
1050 if ( (cutthrough.delivery || options & vopt_callout_hold)
1054 && (options & (vopt_callout_recipsender|vopt_callout_recippmaster|vopt_success_on_redirect))
1055 == vopt_callout_recipsender
1056 && !random_local_part
1058 && cutthrough.cctx.sock < 0
1062 HDEBUG(D_acl|D_v) debug_printf_indent("holding verify callout open for %s\n",
1064 ? "cutthrough delivery" : "potential further verifies and delivery");
1066 cutthrough.callout_hold_only = !cutthrough.delivery;
1067 cutthrough.is_tls = tls_out.active.sock >= 0;
1068 /* We assume no buffer in use in the outblock */
1069 cutthrough.cctx = sx.cctx;
1070 cutthrough.nrcpt = 1;
1071 cutthrough.transport = addr->transport->name;
1072 cutthrough.interface = interface;
1073 cutthrough.snd_port = sending_port;
1074 cutthrough.peer_options = smtp_peer_options;
1075 cutthrough.host = *host;
1077 int oldpool = store_pool;
1078 store_pool = POOL_PERM;
1079 cutthrough.snd_ip = string_copy(sending_ip_address);
1080 cutthrough.host.name = string_copy(host->name);
1081 cutthrough.host.address = string_copy(host->address);
1082 store_pool = oldpool;
1085 /* Save the address_item and parent chain for later logging */
1086 cutthrough.addr = *addr;
1087 cutthrough.addr.next = NULL;
1088 cutthrough.addr.host_used = &cutthrough.host;
1089 for (address_item * caddr = &cutthrough.addr, * parent = addr->parent;
1091 caddr = caddr->parent, parent = parent->parent)
1092 *(caddr->parent = store_get(sizeof(address_item))) = *parent;
1094 ctctx.outblock.buffer = ctbuffer;
1095 ctctx.outblock.buffersize = sizeof(ctbuffer);
1096 ctctx.outblock.ptr = ctbuffer;
1097 /* ctctx.outblock.cmd_count = 0; ctctx.outblock.authenticating = FALSE; */
1098 ctctx.outblock.cctx = &cutthrough.cctx;
1102 /* Ensure no cutthrough on multiple verifies that were incompatible */
1103 if (options & vopt_callout_recipsender)
1104 cancel_cutthrough_connection(TRUE, US"not usable for cutthrough");
1106 if (smtp_write_command(&sx, SCMD_FLUSH, "QUIT\r\n") != -1)
1107 /* Wait a short time for response, and discard it */
1108 smtp_read_response(&sx, sx.buffer, sizeof(sx.buffer), '2', 1);
1110 if (sx.cctx.sock >= 0)
1113 if (sx.cctx.tls_ctx)
1115 tls_close(sx.cctx.tls_ctx, TLS_SHUTDOWN_NOWAIT);
1116 sx.cctx.tls_ctx = NULL;
1119 HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP(close)>>\n");
1120 (void)close(sx.cctx.sock);
1122 #ifndef DISABLE_EVENT
1123 (void) event_raise(addr->transport->event_action, US"tcp:close", NULL);
1128 if (!done || yield != OK)
1129 addr->message = string_sprintf("%s [%s] : %s", host->name, host->address,
1131 } /* Loop through all hosts, while !done */
1134 /* If we get here with done == TRUE, a successful callout happened, and yield
1135 will be set OK or FAIL according to the response to the RCPT command.
1136 Otherwise, we looped through the hosts but couldn't complete the business.
1137 However, there may be domain-specific information to cache in both cases. */
1139 if (!(options & vopt_callout_no_cache))
1140 cache_callout_write(&new_domain_record, addr->domain,
1141 done, &new_address_record, address_key);
1143 /* Failure to connect to any host, or any response other than 2xx or 5xx is a
1144 temporary error. If there was only one host, and a response was received, leave
1145 it alone if supplying details. Otherwise, give a generic response. */
1149 uschar * dullmsg = string_sprintf("Could not complete %s verify callout",
1150 options & vopt_is_recipient ? "recipient" : "sender");
1153 addr->message = host_list->next || !addr->message
1154 ? dullmsg : string_sprintf("%s: %s", dullmsg, addr->message);
1156 addr->user_message = smtp_return_error_details
1157 ? string_sprintf("%s for <%s>.\n"
1158 "The mail server(s) for the domain may be temporarily unreachable, or\n"
1159 "they may be permanently unreachable from this server. In the latter case,\n%s",
1160 dullmsg, addr->address,
1161 options & vopt_is_recipient
1162 ? "the address will never be accepted."
1163 : "you need to change the address or create an MX record for its domain\n"
1164 "if it is supposed to be generally accessible from the Internet.\n"
1165 "Talk to your mail administrator for details.")
1168 /* Force a specific error code */
1170 addr->basic_errno = ERRNO_CALLOUTDEFER;
1173 /* Come here from within the cache-reading code on fast-track exit. */
1176 tls_modify_variables(&tls_in);
1182 /* Called after recipient-acl to get a cutthrough connection open when
1183 one was requested and a recipient-verify wasn't subsequently done.
1186 open_cutthrough_connection(address_item * addr)
1191 /* Use a recipient-verify-callout to set up the cutthrough connection. */
1192 /* We must use a copy of the address for verification, because it might
1196 HDEBUG(D_acl) debug_printf_indent("----------- %s cutthrough setup ------------\n",
1197 rcpt_count > 1 ? "more" : "start");
1198 rc = verify_address(&addr2, NULL,
1199 vopt_is_recipient | vopt_callout_recipsender | vopt_callout_no_cache,
1200 CUTTHROUGH_CMD_TIMEOUT, -1, -1,
1202 addr->message = addr2.message;
1203 addr->user_message = addr2.user_message;
1204 HDEBUG(D_acl) debug_printf_indent("----------- end cutthrough setup ------------\n");
1210 /* Send given number of bytes from the buffer */
1212 cutthrough_send(int n)
1214 if(cutthrough.cctx.sock < 0)
1220 ? tls_write(cutthrough.cctx.tls_ctx, ctctx.outblock.buffer, n, FALSE)
1223 send(cutthrough.cctx.sock, ctctx.outblock.buffer, n, 0) > 0
1226 transport_count += n;
1227 ctctx.outblock.ptr= ctctx.outblock.buffer;
1231 HDEBUG(D_transport|D_acl) debug_printf_indent("cutthrough_send failed: %s\n", strerror(errno));
1238 _cutthrough_puts(uschar * cp, int n)
1242 if(ctctx.outblock.ptr >= ctctx.outblock.buffer+ctctx.outblock.buffersize)
1243 if(!cutthrough_send(ctctx.outblock.buffersize))
1246 *ctctx.outblock.ptr++ = *cp++;
1251 /* Buffered output of counted data block. Return boolean success */
1253 cutthrough_puts(uschar * cp, int n)
1255 if (cutthrough.cctx.sock < 0) return TRUE;
1256 if (_cutthrough_puts(cp, n)) return TRUE;
1257 cancel_cutthrough_connection(TRUE, US"transmit failed");
1262 cutthrough_data_puts(uschar * cp, int n)
1264 if (cutthrough.delivery) (void) cutthrough_puts(cp, n);
1270 _cutthrough_flush_send(void)
1272 int n = ctctx.outblock.ptr - ctctx.outblock.buffer;
1275 if(!cutthrough_send(n))
1281 /* Send out any bufferred output. Return boolean success. */
1283 cutthrough_flush_send(void)
1285 if (_cutthrough_flush_send()) return TRUE;
1286 cancel_cutthrough_connection(TRUE, US"transmit failed");
1292 cutthrough_put_nl(void)
1294 return cutthrough_puts(US"\r\n", 2);
1299 cutthrough_data_put_nl(void)
1301 cutthrough_data_puts(US"\r\n", 2);
1305 /* Get and check response from cutthrough target */
1307 cutthrough_response(client_conn_ctx * cctx, char expect, uschar ** copy, int timeout)
1309 smtp_context sx = {0};
1310 uschar inbuffer[4096];
1311 uschar responsebuffer[4096];
1313 sx.inblock.buffer = inbuffer;
1314 sx.inblock.buffersize = sizeof(inbuffer);
1315 sx.inblock.ptr = inbuffer;
1316 sx.inblock.ptrend = inbuffer;
1317 sx.inblock.cctx = cctx;
1318 if(!smtp_read_response(&sx, responsebuffer, sizeof(responsebuffer), expect, timeout))
1319 cancel_cutthrough_connection(TRUE, US"target timeout on read");
1324 *copy = cp = string_copy(responsebuffer);
1325 /* Trim the trailing end of line */
1326 cp += Ustrlen(responsebuffer);
1327 if(cp > *copy && cp[-1] == '\n') *--cp = '\0';
1328 if(cp > *copy && cp[-1] == '\r') *--cp = '\0';
1331 return responsebuffer[0];
1335 /* Negotiate dataphase with the cutthrough target, returning success boolean */
1337 cutthrough_predata(void)
1339 if(cutthrough.cctx.sock < 0 || cutthrough.callout_hold_only)
1342 HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP>> DATA\n");
1343 cutthrough_puts(US"DATA\r\n", 6);
1344 cutthrough_flush_send();
1346 /* Assume nothing buffered. If it was it gets ignored. */
1347 return cutthrough_response(&cutthrough.cctx, '3', NULL, CUTTHROUGH_DATA_TIMEOUT) == '3';
1351 /* tctx arg only to match write_chunk() */
1353 cutthrough_write_chunk(transport_ctx * tctx, uschar * s, int len)
1356 while(s && (s2 = Ustrchr(s, '\n')))
1358 if(!cutthrough_puts(s, s2-s) || !cutthrough_put_nl())
1366 /* Buffered send of headers. Return success boolean. */
1367 /* Expands newlines to wire format (CR,NL). */
1368 /* Also sends header-terminating blank line. */
1370 cutthrough_headers_send(void)
1374 if(cutthrough.cctx.sock < 0 || cutthrough.callout_hold_only)
1377 /* We share a routine with the mainline transport to handle header add/remove/rewrites,
1378 but having a separate buffered-output function (for now)
1380 HDEBUG(D_acl) debug_printf_indent("----------- start cutthrough headers send -----------\n");
1382 tctx.u.fd = cutthrough.cctx.sock;
1383 tctx.tblock = cutthrough.addr.transport;
1384 tctx.addr = &cutthrough.addr;
1385 tctx.check_string = US".";
1386 tctx.escape_string = US"..";
1387 /*XXX check under spool_files_wireformat. Might be irrelevant */
1388 tctx.options = topt_use_crlf;
1390 if (!transport_headers_send(&tctx, &cutthrough_write_chunk))
1393 HDEBUG(D_acl) debug_printf_indent("----------- done cutthrough headers send ------------\n");
1399 close_cutthrough_connection(const uschar * why)
1401 int fd = cutthrough.cctx.sock;
1404 /* We could be sending this after a bunch of data, but that is ok as
1405 the only way to cancel the transfer in dataphase is to drop the tcp
1406 conn before the final dot.
1408 client_conn_ctx tmp_ctx = cutthrough.cctx;
1409 ctctx.outblock.ptr = ctbuffer;
1410 HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP>> QUIT\n");
1411 _cutthrough_puts(US"QUIT\r\n", 6); /* avoid recursion */
1412 _cutthrough_flush_send();
1413 cutthrough.cctx.sock = -1; /* avoid recursion via read timeout */
1414 cutthrough.nrcpt = 0; /* permit re-cutthrough on subsequent message */
1416 /* Wait a short time for response, and discard it */
1417 cutthrough_response(&tmp_ctx, '2', NULL, 1);
1420 if (cutthrough.is_tls)
1422 tls_close(cutthrough.cctx.tls_ctx, TLS_SHUTDOWN_NOWAIT);
1423 cutthrough.cctx.tls_ctx = NULL;
1424 cutthrough.is_tls = FALSE;
1427 HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP(close)>>\n");
1429 HDEBUG(D_acl) debug_printf_indent("----------- cutthrough shutdown (%s) ------------\n", why);
1431 ctctx.outblock.ptr = ctbuffer;
1435 cancel_cutthrough_connection(BOOL close_noncutthrough_verifies, const uschar * why)
1437 if (cutthrough.delivery || close_noncutthrough_verifies)
1438 close_cutthrough_connection(why);
1439 cutthrough.delivery = cutthrough.callout_hold_only = FALSE;
1444 release_cutthrough_connection(const uschar * why)
1446 if (cutthrough.cctx.sock < 0) return;
1447 HDEBUG(D_acl) debug_printf_indent("release cutthrough conn: %s\n", why);
1448 cutthrough.cctx.sock = -1;
1449 cutthrough.cctx.tls_ctx = NULL;
1450 cutthrough.delivery = cutthrough.callout_hold_only = FALSE;
1456 /* Have senders final-dot. Send one to cutthrough target, and grab the response.
1457 Log an OK response as a transmission.
1458 Close the connection.
1459 Return smtp response-class digit.
1462 cutthrough_finaldot(void)
1465 HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP>> .\n");
1467 /* Assume data finshed with new-line */
1468 if( !cutthrough_puts(US".", 1)
1469 || !cutthrough_put_nl()
1470 || !cutthrough_flush_send()
1472 return cutthrough.addr.message;
1474 res = cutthrough_response(&cutthrough.cctx, '2', &cutthrough.addr.message,
1475 CUTTHROUGH_DATA_TIMEOUT);
1476 for (address_item * addr = &cutthrough.addr; addr; addr = addr->next)
1478 addr->message = cutthrough.addr.message;
1482 delivery_log(LOG_MAIN, addr, (int)'>', NULL);
1483 close_cutthrough_connection(US"delivered");
1487 delivery_log(LOG_MAIN, addr, 0,
1488 US"tmp-reject from cutthrough after DATA:");
1492 delivery_log(LOG_MAIN|LOG_REJECT, addr, 0,
1493 US"rejected after DATA:");
1500 return cutthrough.addr.message;
1505 /*************************************************
1506 * Copy error to toplevel address *
1507 *************************************************/
1509 /* This function is used when a verify fails or defers, to ensure that the
1510 failure or defer information is in the original toplevel address. This applies
1511 when an address is redirected to a single new address, and the failure or
1512 deferral happens to the child address.
1515 vaddr the verify address item
1516 addr the final address item
1519 Returns: the value of YIELD
1523 copy_error(address_item *vaddr, address_item *addr, int yield)
1527 vaddr->message = addr->message;
1528 vaddr->user_message = addr->user_message;
1529 vaddr->basic_errno = addr->basic_errno;
1530 vaddr->more_errno = addr->more_errno;
1531 vaddr->prop.address_data = addr->prop.address_data;
1532 vaddr->prop.variables = NULL;
1533 tree_dup((tree_node **)&vaddr->prop.variables, addr->prop.variables);
1534 copyflag(vaddr, addr, af_pass_message);
1542 /**************************************************
1543 * printf that automatically handles TLS if needed *
1544 ***************************************************/
1546 /* This function is used by verify_address() as a substitute for all fprintf()
1547 calls; a direct fprintf() will not produce output in a TLS SMTP session, such
1548 as a response to an EXPN command. smtp_in.c makes smtp_printf available but
1549 that assumes that we always use the smtp_out FILE* when not using TLS or the
1550 ssl buffer when we are. Instead we take a FILE* parameter and check to see if
1551 that is smtp_out; if so, smtp_printf() with TLS support, otherwise regular
1555 f the candidate FILE* to write to
1556 format format string
1557 ... optional arguments
1563 static void PRINTF_FUNCTION(2,3)
1564 respond_printf(FILE *f, const char *format, ...)
1568 va_start(ap, format);
1569 if (smtp_out && (f == smtp_out))
1570 smtp_vprintf(format, FALSE, ap);
1572 vfprintf(f, format, ap);
1578 /*************************************************
1579 * Verify an email address *
1580 *************************************************/
1582 /* This function is used both for verification (-bv and at other times) and
1583 address testing (-bt), which is indicated by address_test_mode being set.
1586 vaddr contains the address to verify; the next field in this block
1588 f if not NULL, write the result to this file
1589 options various option bits:
1590 vopt_fake_sender => this sender verify is not for the real
1591 sender (it was verify=sender=xxxx or an address from a
1592 header line) - rewriting must not change sender_address
1593 vopt_is_recipient => this is a recipient address, otherwise
1594 it's a sender address - this affects qualification and
1595 rewriting and messages from callouts
1596 vopt_qualify => qualify an unqualified address; else error
1597 vopt_expn => called from SMTP EXPN command
1598 vopt_success_on_redirect => when a new address is generated
1599 the verification instantly succeeds
1601 These ones are used by do_callout() -- the options variable
1604 vopt_callout_fullpm => if postmaster check, do full one
1605 vopt_callout_no_cache => don't use callout cache
1606 vopt_callout_random => do the "random" thing
1607 vopt_callout_recipsender => use real sender for recipient
1608 vopt_callout_recippmaster => use postmaster for recipient
1610 callout if > 0, specifies that callout is required, and gives timeout
1611 for individual commands
1612 callout_overall if > 0, gives overall timeout for the callout function;
1613 if < 0, a default is used (see do_callout())
1614 callout_connect the connection timeout for callouts
1615 se_mailfrom when callout is requested to verify a sender, use this
1616 in MAIL FROM; NULL => ""
1617 pm_mailfrom when callout is requested, if non-NULL, do the postmaster
1618 thing and use this as the sender address (may be "")
1620 routed if not NULL, set TRUE if routing succeeded, so we can
1621 distinguish between routing failed and callout failed
1623 Returns: OK address verified
1624 FAIL address failed to verify
1625 DEFER can't tell at present
1629 verify_address(address_item * vaddr, FILE * fp, int options, int callout,
1630 int callout_overall, int callout_connect, uschar * se_mailfrom,
1631 uschar *pm_mailfrom, BOOL *routed)
1634 BOOL full_info = fp ? debug_selector != 0 : FALSE;
1635 BOOL expn = (options & vopt_expn) != 0;
1636 BOOL success_on_redirect = (options & vopt_success_on_redirect) != 0;
1639 int verify_type = expn? v_expn :
1640 f.address_test_mode? v_none :
1641 options & vopt_is_recipient? v_recipient : v_sender;
1642 address_item *addr_list;
1643 address_item *addr_new = NULL;
1644 address_item *addr_remote = NULL;
1645 address_item *addr_local = NULL;
1646 address_item *addr_succeed = NULL;
1647 uschar **failure_ptr = options & vopt_is_recipient
1648 ? &recipient_verify_failure : &sender_verify_failure;
1649 uschar *ko_prefix, *cr;
1650 uschar *address = vaddr->address;
1651 uschar *save_sender;
1652 uschar null_sender[] = { 0 }; /* Ensure writeable memory */
1654 /* Clear, just in case */
1656 *failure_ptr = NULL;
1658 /* Set up a prefix and suffix for error message which allow us to use the same
1659 output statements both in EXPN mode (where an SMTP response is needed) and when
1660 debugging with an output file. */
1664 ko_prefix = US"553 ";
1667 else ko_prefix = cr = US"";
1669 /* Add qualify domain if permitted; otherwise an unqualified address fails. */
1671 if (parse_find_at(address) == NULL)
1673 if (!(options & vopt_qualify))
1676 respond_printf(fp, "%sA domain is required for \"%s\"%s\n",
1677 ko_prefix, address, cr);
1678 *failure_ptr = US"qualify";
1681 address = rewrite_address_qualify(address, options & vopt_is_recipient);
1686 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1687 debug_printf("%s %s\n", f.address_test_mode? "Testing" : "Verifying", address);
1690 /* Rewrite and report on it. Clear the domain and local part caches - these
1691 may have been set by domains and local part tests during an ACL. */
1693 if (global_rewrite_rules)
1695 uschar *old = address;
1696 address = rewrite_address(address, options & vopt_is_recipient, FALSE,
1697 global_rewrite_rules, rewrite_existflags);
1700 for (int i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->localpart_cache[i] = 0;
1701 for (int i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->domain_cache[i] = 0;
1702 if (fp && !expn) fprintf(fp, "Address rewritten as: %s\n", address);
1706 /* If this is the real sender address, we must update sender_address at
1707 this point, because it may be referred to in the routers. */
1709 if (!(options & (vopt_fake_sender|vopt_is_recipient)))
1710 sender_address = address;
1712 /* If the address was rewritten to <> no verification can be done, and we have
1713 to return OK. This rewriting is permitted only for sender addresses; for other
1714 addresses, such rewriting fails. */
1716 if (!address[0]) return OK;
1718 /* Flip the legacy TLS-related variables over to the outbound set in case
1719 they're used in the context of a transport used by verification. Reset them
1720 at exit from this routine (so no returns allowed from here on). */
1722 tls_modify_variables(&tls_out);
1724 /* Save a copy of the sender address for re-instating if we change it to <>
1725 while verifying a sender address (a nice bit of self-reference there). */
1727 save_sender = sender_address;
1729 /* Observability variable for router/transport use */
1731 verify_mode = options & vopt_is_recipient ? US"R" : US"S";
1733 /* Update the address structure with the possibly qualified and rewritten
1734 address. Set it up as the starting address on the chain of new addresses. */
1736 vaddr->address = address;
1739 /* We need a loop, because an address can generate new addresses. We must also
1740 cope with generated pipes and files at the top level. (See also the code and
1741 comment in deliver.c.) However, it is usually the case that the router for
1742 user's .forward files has its verify flag turned off.
1744 If an address generates more than one child, the loop is used only when
1745 full_info is set, and this can only be set locally. Remote enquiries just get
1746 information about the top level address, not anything that it generated. */
1751 address_item *addr = addr_new;
1753 addr_new = addr->next;
1758 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1759 debug_printf("Considering %s\n", addr->address);
1762 /* Handle generated pipe, file or reply addresses. We don't get these
1763 when handling EXPN, as it does only one level of expansion. */
1765 if (testflag(addr, af_pfr))
1772 if (addr->address[0] == '>')
1774 allow = testflag(addr, af_allow_reply);
1775 fprintf(fp, "%s -> mail %s", addr->parent->address, addr->address + 1);
1779 allow = addr->address[0] == '|'
1780 ? testflag(addr, af_allow_pipe) : testflag(addr, af_allow_file);
1781 fprintf(fp, "%s -> %s", addr->parent->address, addr->address);
1784 if (addr->basic_errno == ERRNO_BADTRANSPORT)
1785 fprintf(fp, "\n*** Error in setting up pipe, file, or autoreply:\n"
1786 "%s\n", addr->message);
1788 fprintf(fp, "\n transport = %s\n", addr->transport->name);
1790 fprintf(fp, " *** forbidden ***\n");
1795 /* Just in case some router parameter refers to it. */
1797 return_path = addr->prop.errors_address
1798 ? addr->prop.errors_address : sender_address;
1800 /* Split the address into domain and local part, handling the %-hack if
1801 necessary, and then route it. While routing a sender address, set
1802 $sender_address to <> because that is what it will be if we were trying to
1803 send a bounce to the sender. */
1805 if (routed) *routed = FALSE;
1806 if ((rc = deliver_split_address(addr)) == OK)
1808 if (!(options & vopt_is_recipient)) sender_address = null_sender;
1809 rc = route_address(addr, &addr_local, &addr_remote, &addr_new,
1810 &addr_succeed, verify_type);
1811 sender_address = save_sender; /* Put back the real sender */
1814 /* If routing an address succeeded, set the flag that remembers, for use when
1815 an ACL cached a sender verify (in case a callout fails). Then if routing set
1816 up a list of hosts or the transport has a host list, and the callout option
1817 is set, and we aren't in a host checking run, do the callout verification,
1818 and set another flag that notes that a callout happened. */
1822 if (routed) *routed = TRUE;
1825 transport_instance * tp;
1826 host_item * host_list = addr->host_list;
1828 /* Make up some data for use in the case where there is no remote
1831 transport_feedback tf = {
1832 .interface = NULL, /* interface (=> any) */
1834 .protocol = US"smtp",
1836 .helo_data = US"$smtp_active_hostname",
1837 .hosts_override = FALSE,
1838 .hosts_randomize = FALSE,
1839 .gethostbyname = FALSE,
1840 .qualify_single = TRUE,
1841 .search_parents = FALSE
1844 /* If verification yielded a remote transport, we want to use that
1845 transport's options, so as to mimic what would happen if we were really
1846 sending a message to this address. */
1848 if ((tp = addr->transport) && !tp->info->local)
1850 (void)(tp->setup)(tp, addr, &tf, 0, 0, NULL);
1852 /* If the transport has hosts and the router does not, or if the
1853 transport is configured to override the router's hosts, we must build a
1854 host list of the transport's hosts, and find the IP addresses */
1856 if (tf.hosts && (!host_list || tf.hosts_override))
1859 const uschar *save_deliver_domain = deliver_domain;
1860 uschar *save_deliver_localpart = deliver_localpart;
1862 host_list = NULL; /* Ignore the router's hosts */
1864 deliver_domain = addr->domain;
1865 deliver_localpart = addr->local_part;
1866 s = expand_string(tf.hosts);
1867 deliver_domain = save_deliver_domain;
1868 deliver_localpart = save_deliver_localpart;
1872 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand list of hosts "
1873 "\"%s\" in %s transport for callout: %s", tf.hosts,
1874 tp->name, expand_string_message);
1879 host_build_hostlist(&host_list, s, tf.hosts_randomize);
1881 /* Just ignore failures to find a host address. If we don't manage
1882 to find any addresses, the callout will defer. Note that more than
1883 one address may be found for a single host, which will result in
1884 additional host items being inserted into the chain. Hence we must
1885 save the next host first. */
1887 flags = HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
1888 if (tf.qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
1889 if (tf.search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
1891 for (host_item * host = host_list, * nexthost; host; host = nexthost)
1893 nexthost = host->next;
1894 if (tf.gethostbyname ||
1895 string_is_ip_address(host->name, NULL) != 0)
1896 (void)host_find_byname(host, NULL, flags, NULL, TRUE);
1899 const dnssec_domains * dsp = NULL;
1900 if (Ustrcmp(tp->driver_name, "smtp") == 0)
1902 smtp_transport_options_block * ob =
1903 (smtp_transport_options_block *) tp->options_block;
1907 (void) host_find_bydns(host, NULL, flags, NULL, NULL, NULL,
1915 /* Can only do a callout if we have at least one host! If the callout
1916 fails, it will have set ${sender,recipient}_verify_failure. */
1920 HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n");
1921 if (host_checking && !f.host_checking_callout)
1924 debug_printf("... callout omitted by default when host testing\n"
1925 "(Use -bhc if you want the callouts to happen.)\n");
1930 deliver_set_expansions(addr);
1932 rc = do_callout(addr, host_list, &tf, callout, callout_overall,
1933 callout_connect, options, se_mailfrom, pm_mailfrom);
1935 deliver_set_expansions(NULL);
1941 HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor "
1942 "transport provided a host list, or transport is not smtp\n");
1947 /* Otherwise, any failure is a routing failure */
1949 else *failure_ptr = US"route";
1951 /* A router may return REROUTED if it has set up a child address as a result
1952 of a change of domain name (typically from widening). In this case we always
1953 want to continue to verify the new child. */
1955 if (rc == REROUTED) continue;
1957 /* Handle hard failures */
1964 address_item *p = addr->parent;
1966 respond_printf(fp, "%s%s %s", ko_prefix,
1967 full_info ? addr->address : address,
1968 f.address_test_mode ? "is undeliverable" : "failed to verify");
1969 if (!expn && f.admin_user)
1971 if (addr->basic_errno > 0)
1972 respond_printf(fp, ": %s", strerror(addr->basic_errno));
1974 respond_printf(fp, ": %s", addr->message);
1977 /* Show parents iff doing full info */
1979 if (full_info) while (p)
1981 respond_printf(fp, "%s\n <-- %s", cr, p->address);
1984 respond_printf(fp, "%s\n", cr);
1986 cancel_cutthrough_connection(TRUE, US"routing hard fail");
1990 yield = copy_error(vaddr, addr, FAIL);
1998 else if (rc == DEFER)
2003 address_item *p = addr->parent;
2004 respond_printf(fp, "%s%s cannot be resolved at this time", ko_prefix,
2005 full_info? addr->address : address);
2006 if (!expn && f.admin_user)
2008 if (addr->basic_errno > 0)
2009 respond_printf(fp, ": %s", strerror(addr->basic_errno));
2011 respond_printf(fp, ": %s", addr->message);
2012 else if (addr->basic_errno <= 0)
2013 respond_printf(fp, ": unknown error");
2016 /* Show parents iff doing full info */
2018 if (full_info) while (p)
2020 respond_printf(fp, "%s\n <-- %s", cr, p->address);
2023 respond_printf(fp, "%s\n", cr);
2025 cancel_cutthrough_connection(TRUE, US"routing soft fail");
2029 yield = copy_error(vaddr, addr, DEFER);
2032 if (yield == OK) yield = DEFER;
2035 /* If we are handling EXPN, we do not want to continue to route beyond
2036 the top level (whose address is in "address"). */
2040 uschar *ok_prefix = US"250-";
2043 if (!addr_local && !addr_remote)
2044 respond_printf(fp, "250 mail to <%s> is discarded\r\n", address);
2046 respond_printf(fp, "250 <%s>\r\n", address);
2050 address_item *addr2 = addr_new;
2051 addr_new = addr2->next;
2052 if (!addr_new) ok_prefix = US"250 ";
2053 respond_printf(fp, "%s<%s>\r\n", ok_prefix, addr2->address);
2059 /* Successful routing other than EXPN. */
2063 /* Handle successful routing when short info wanted. Otherwise continue for
2064 other (generated) addresses. Short info is the operational case. Full info
2065 can be requested only when debug_selector != 0 and a file is supplied.
2067 There is a conflict between the use of aliasing as an alternate email
2068 address, and as a sort of mailing list. If an alias turns the incoming
2069 address into just one address (e.g. J.Caesar->jc44) you may well want to
2070 carry on verifying the generated address to ensure it is valid when
2071 checking incoming mail. If aliasing generates multiple addresses, you
2072 probably don't want to do this. Exim therefore treats the generation of
2073 just a single new address as a special case, and continues on to verify the
2074 generated address. */
2076 if ( !full_info /* Stop if short info wanted AND */
2077 && ( ( !addr_new /* No new address OR */
2078 || addr_new->next /* More than one new address OR */
2079 || testflag(addr_new, af_pfr) /* New address is pfr */
2082 ( addr_new /* At least one new address AND */
2083 && success_on_redirect /* success_on_redirect is set */
2087 if (fp) fprintf(fp, "%s %s\n",
2088 address, f.address_test_mode ? "is deliverable" : "verified");
2090 /* If we have carried on to verify a child address, we want the value
2091 of $address_data to be that of the child */
2093 vaddr->prop.address_data = addr->prop.address_data;
2094 vaddr->prop.variables = NULL;
2095 tree_dup((tree_node **)&vaddr->prop.variables, addr->prop.variables);
2097 /* If stopped because more than one new address, cannot cutthrough */
2099 if (addr_new && addr_new->next)
2100 cancel_cutthrough_connection(TRUE, US"multiple addresses from routing");
2106 } /* Loop for generated addresses */
2108 /* Display the full results of the successful routing, including any generated
2109 addresses. Control gets here only when full_info is set, which requires fp not
2110 to be NULL, and this occurs only when a top-level verify is called with the
2111 debugging switch on.
2113 If there are no local and no remote addresses, and there were no pipes, files,
2114 or autoreplies, and there were no errors or deferments, the message is to be
2115 discarded, usually because of the use of :blackhole: in an alias file. */
2117 if (allok && !addr_local && !addr_remote)
2119 fprintf(fp, "mail to %s is discarded\n", address);
2123 for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++)
2126 address_item *addr = addr_list;
2127 transport_instance * tp = addr->transport;
2129 addr_list = addr->next;
2131 fprintf(fp, "%s", CS addr->address);
2132 #ifdef EXPERIMENTAL_SRS
2133 if(addr->prop.srs_sender)
2134 fprintf(fp, " [srs = %s]", addr->prop.srs_sender);
2137 /* If the address is a duplicate, show something about it. */
2139 if (!testflag(addr, af_pfr))
2142 if ((tnode = tree_search(tree_duplicates, addr->unique)))
2143 fprintf(fp, " [duplicate, would not be delivered]");
2144 else tree_add_duplicate(addr->unique, addr);
2147 /* Now show its parents */
2149 for (address_item * p = addr->parent; p; p = p->parent)
2150 fprintf(fp, "\n <-- %s", p->address);
2153 /* Show router, and transport */
2155 fprintf(fp, "router = %s, transport = %s\n",
2156 addr->router->name, tp ? tp->name : US"unset");
2158 /* Show any hosts that are set up by a router unless the transport
2159 is going to override them; fiddle a bit to get a nice format. */
2161 if (addr->host_list && tp && !tp->overrides_hosts)
2165 for (host_item * h = addr->host_list; h; h = h->next)
2166 { /* get max lengths of host names, addrs */
2167 int len = Ustrlen(h->name);
2168 if (len > maxlen) maxlen = len;
2169 len = h->address ? Ustrlen(h->address) : 7;
2170 if (len > maxaddlen) maxaddlen = len;
2172 for (host_item * h = addr->host_list; h; h = h->next)
2174 fprintf(fp, " host %-*s ", maxlen, h->name);
2177 fprintf(fp, "[%s%-*c", h->address, maxaddlen+1 - Ustrlen(h->address), ']');
2178 else if (tp->info->local)
2179 fprintf(fp, " %-*s ", maxaddlen, ""); /* Omit [unknown] for local */
2181 fprintf(fp, "[%s%-*c", "unknown", maxaddlen+1 - 7, ']');
2183 if (h->mx >= 0) fprintf(fp, " MX=%d", h->mx);
2184 if (h->port != PORT_NONE) fprintf(fp, " port=%d", h->port);
2185 if (f.running_in_test_harness && h->dnssec == DS_YES) fputs(" AD", fp);
2186 if (h->status == hstatus_unusable) fputs(" ** unusable **", fp);
2192 /* Yield will be DEFER or FAIL if any one address has, only for full_info (which is
2193 the -bv or -bt case). */
2197 tls_modify_variables(&tls_in);
2205 /*************************************************
2206 * Check headers for syntax errors *
2207 *************************************************/
2209 /* This function checks those header lines that contain addresses, and verifies
2210 that all the addresses therein are 5322-syntactially correct.
2213 msgptr where to put an error message
2220 verify_check_headers(uschar **msgptr)
2225 for (header_line * h = header_list; h && yield == OK; h = h->next)
2227 if (h->type != htype_from &&
2228 h->type != htype_reply_to &&
2229 h->type != htype_sender &&
2230 h->type != htype_to &&
2231 h->type != htype_cc &&
2232 h->type != htype_bcc)
2235 colon = Ustrchr(h->text, ':');
2237 while (isspace(*s)) s++;
2239 /* Loop for multiple addresses in the header, enabling group syntax. Note
2240 that we have to reset this after the header has been scanned. */
2242 f.parse_allow_group = TRUE;
2246 uschar *ss = parse_find_address_end(s, FALSE);
2247 uschar *recipient, *errmess;
2248 int terminator = *ss;
2249 int start, end, domain;
2251 /* Temporarily terminate the string at this point, and extract the
2252 operative address within, allowing group syntax. */
2255 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2258 /* Permit an unqualified address only if the message is local, or if the
2259 sending host is configured to be permitted to send them. */
2261 if (recipient && !domain)
2263 if (h->type == htype_from || h->type == htype_sender)
2265 if (!f.allow_unqualified_sender) recipient = NULL;
2269 if (!f.allow_unqualified_recipient) recipient = NULL;
2271 if (recipient == NULL) errmess = US"unqualified address not permitted";
2274 /* It's an error if no address could be extracted, except for the special
2275 case of an empty address. */
2277 if (!recipient && Ustrcmp(errmess, "empty address") != 0)
2279 uschar *verb = US"is";
2284 /* Arrange not to include any white space at the end in the
2285 error message or the header name. */
2287 while (t > s && isspace(t[-1])) t--;
2288 while (tt > h->text && isspace(tt[-1])) tt--;
2290 /* Add the address that failed to the error message, since in a
2291 header with very many addresses it is sometimes hard to spot
2292 which one is at fault. However, limit the amount of address to
2293 quote - cases have been seen where, for example, a missing double
2294 quote in a humungous To: header creates an "address" that is longer
2295 than string_sprintf can handle. */
2304 /* deconst cast ok as we're passing a non-const to string_printing() */
2305 *msgptr = US string_printing(
2306 string_sprintf("%s: failing address in \"%.*s:\" header %s: %.*s",
2307 errmess, (int)(tt - h->text), h->text, verb, len, s));
2310 break; /* Out of address loop */
2313 /* Advance to the next address */
2315 s = ss + (terminator ? 1 : 0);
2316 while (isspace(*s)) s++;
2317 } /* Next address */
2319 f.parse_allow_group = FALSE;
2320 f.parse_found_group = FALSE;
2321 } /* Next header unless yield has been set FALSE */
2327 /*************************************************
2328 * Check header names for 8-bit characters *
2329 *************************************************/
2331 /* This function checks for invalid characters in header names. See
2332 RFC 5322, 2.2. and RFC 6532, 3.
2335 msgptr where to put an error message
2342 verify_check_header_names_ascii(uschar **msgptr)
2346 for (header_line * h = header_list; h; h = h->next)
2348 colon = Ustrchr(h->text, ':');
2349 for(uschar * s = h->text; s < colon; s++)
2350 if ((*s < 33) || (*s > 126))
2352 *msgptr = string_sprintf("Invalid character in header \"%.*s\" found",
2353 colon - h->text, h->text);
2360 /*************************************************
2361 * Check for blind recipients *
2362 *************************************************/
2364 /* This function checks that every (envelope) recipient is mentioned in either
2365 the To: or Cc: header lines, thus detecting blind carbon copies.
2367 There are two ways of scanning that could be used: either scan the header lines
2368 and tick off the recipients, or scan the recipients and check the header lines.
2369 The original proposed patch did the former, but I have chosen to do the latter,
2370 because (a) it requires no memory and (b) will use fewer resources when there
2371 are many addresses in To: and/or Cc: and only one or two envelope recipients.
2373 Arguments: case_sensitive true if case sensitive matching should be used
2374 Returns: OK if there are no blind recipients
2375 FAIL if there is at least one blind recipient
2379 verify_check_notblind(BOOL case_sensitive)
2381 for (int i = 0; i < recipients_count; i++)
2384 uschar *address = recipients_list[i].address;
2386 for (header_line * h = header_list; !found && h; h = h->next)
2390 if (h->type != htype_to && h->type != htype_cc) continue;
2392 colon = Ustrchr(h->text, ':');
2394 while (isspace(*s)) s++;
2396 /* Loop for multiple addresses in the header, enabling group syntax. Note
2397 that we have to reset this after the header has been scanned. */
2399 f.parse_allow_group = TRUE;
2403 uschar * ss = parse_find_address_end(s, FALSE);
2404 uschar * recipient, * errmess;
2405 int terminator = *ss;
2406 int start, end, domain;
2408 /* Temporarily terminate the string at this point, and extract the
2409 operative address within, allowing group syntax. */
2412 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2415 /* If we found a valid recipient that has a domain, compare it with the
2416 envelope recipient. Local parts are compared with case-sensitivity
2417 according to the routine arg, domains case-insensitively.
2418 By comparing from the start with length "domain", we include the "@" at
2419 the end, which ensures that we are comparing the whole local part of each
2422 if (recipient && domain != 0)
2423 if ((found = (case_sensitive
2424 ? Ustrncmp(recipient, address, domain) == 0
2425 : strncmpic(recipient, address, domain) == 0)
2426 && strcmpic(recipient + domain, address + domain) == 0))
2429 /* Advance to the next address */
2431 s = ss + (terminator ? 1:0);
2432 while (isspace(*s)) s++;
2433 } /* Next address */
2435 f.parse_allow_group = FALSE;
2436 f.parse_found_group = FALSE;
2437 } /* Next header (if found is false) */
2439 if (!found) return FAIL;
2440 } /* Next recipient */
2447 /*************************************************
2448 * Find if verified sender *
2449 *************************************************/
2451 /* Usually, just a single address is verified as the sender of the message.
2452 However, Exim can be made to verify other addresses as well (often related in
2453 some way), and this is useful in some environments. There may therefore be a
2454 chain of such addresses that have previously been tested. This function finds
2455 whether a given address is on the chain.
2457 Arguments: the address to be verified
2458 Returns: pointer to an address item, or NULL
2462 verify_checked_sender(uschar *sender)
2464 for (address_item * addr = sender_verified_list; addr; addr = addr->next)
2465 if (Ustrcmp(sender, addr->address) == 0) return addr;
2473 /*************************************************
2474 * Get valid header address *
2475 *************************************************/
2477 /* Scan the originator headers of the message, looking for an address that
2478 verifies successfully. RFC 822 says:
2480 o The "Sender" field mailbox should be sent notices of
2481 any problems in transport or delivery of the original
2482 messages. If there is no "Sender" field, then the
2483 "From" field mailbox should be used.
2485 o If the "Reply-To" field exists, then the reply should
2486 go to the addresses indicated in that field and not to
2487 the address(es) indicated in the "From" field.
2489 So we check a Sender field if there is one, else a Reply_to field, else a From
2490 field. As some strange messages may have more than one of these fields,
2491 especially if they are resent- fields, check all of them if there is more than
2495 user_msgptr points to where to put a user error message
2496 log_msgptr points to where to put a log error message
2497 callout timeout for callout check (passed to verify_address())
2498 callout_overall overall callout timeout (ditto)
2499 callout_connect connect callout timeout (ditto)
2500 se_mailfrom mailfrom for verify; NULL => ""
2501 pm_mailfrom sender for pm callout check (passed to verify_address())
2502 options callout options (passed to verify_address())
2503 verrno where to put the address basic_errno
2505 If log_msgptr is set to something without setting user_msgptr, the caller
2506 normally uses log_msgptr for both things.
2508 Returns: result of the verification attempt: OK, FAIL, or DEFER;
2509 FAIL is given if no appropriate headers are found
2513 verify_check_header_address(uschar **user_msgptr, uschar **log_msgptr,
2514 int callout, int callout_overall, int callout_connect, uschar *se_mailfrom,
2515 uschar *pm_mailfrom, int options, int *verrno)
2517 static int header_types[] = { htype_sender, htype_reply_to, htype_from };
2521 for (int i = 0; i < 3 && !done; i++)
2522 for (header_line * h = header_list; h != NULL && !done; h = h->next)
2524 int terminator, new_ok;
2525 uschar *s, *ss, *endname;
2527 if (h->type != header_types[i]) continue;
2528 s = endname = Ustrchr(h->text, ':') + 1;
2530 /* Scan the addresses in the header, enabling group syntax. Note that we
2531 have to reset this after the header has been scanned. */
2533 f.parse_allow_group = TRUE;
2537 address_item *vaddr;
2539 while (isspace(*s) || *s == ',') s++;
2540 if (*s == 0) break; /* End of header */
2542 ss = parse_find_address_end(s, FALSE);
2544 /* The terminator is a comma or end of header, but there may be white
2545 space preceding it (including newline for the last address). Move back
2546 past any white space so we can check against any cached envelope sender
2547 address verifications. */
2549 while (isspace(ss[-1])) ss--;
2553 HDEBUG(D_verify) debug_printf("verifying %.*s header address %s\n",
2554 (int)(endname - h->text), h->text, s);
2556 /* See if we have already verified this address as an envelope sender,
2557 and if so, use the previous answer. */
2559 vaddr = verify_checked_sender(s);
2561 if (vaddr != NULL && /* Previously checked */
2562 (callout <= 0 || /* No callout needed; OR */
2563 vaddr->special_action > 256)) /* Callout was done */
2565 new_ok = vaddr->special_action & 255;
2566 HDEBUG(D_verify) debug_printf("previously checked as envelope sender\n");
2567 *ss = terminator; /* Restore shortened string */
2570 /* Otherwise we run the verification now. We must restore the shortened
2571 string before running the verification, so the headers are correct, in
2572 case there is any rewriting. */
2576 int start, end, domain;
2577 uschar *address = parse_extract_address(s, log_msgptr, &start, &end,
2582 /* If we found an empty address, just carry on with the next one, but
2583 kill the message. */
2585 if (address == NULL && Ustrcmp(*log_msgptr, "empty address") == 0)
2592 /* If verification failed because of a syntax error, fail this
2593 function, and ensure that the failing address gets added to the error
2596 if (address == NULL)
2599 while (ss > s && isspace(ss[-1])) ss--;
2600 *log_msgptr = string_sprintf("syntax error in '%.*s' header when "
2601 "scanning for sender: %s in \"%.*s\"",
2602 (int)(endname - h->text), h->text, *log_msgptr, (int)(ss - s), s);
2608 /* Else go ahead with the sender verification. But it isn't *the*
2609 sender of the message, so set vopt_fake_sender to stop sender_address
2610 being replaced after rewriting or qualification. */
2614 vaddr = deliver_make_addr(address, FALSE);
2615 new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender,
2616 callout, callout_overall, callout_connect, se_mailfrom,
2621 /* We now have the result, either newly found, or cached. If we are
2622 giving out error details, set a specific user error. This means that the
2623 last of these will be returned to the user if all three fail. We do not
2624 set a log message - the generic one below will be used. */
2628 *verrno = vaddr->basic_errno;
2629 if (smtp_return_error_details)
2630 *user_msgptr = string_sprintf("Rejected after DATA: "
2631 "could not verify \"%.*s\" header address\n%s: %s",
2632 (int)(endname - h->text), h->text, vaddr->address, vaddr->message);
2635 /* Success or defer */
2644 if (new_ok == DEFER) yield = DEFER;
2646 /* Move on to any more addresses in the header */
2649 } /* Next address */
2651 f.parse_allow_group = FALSE;
2652 f.parse_found_group = FALSE;
2653 } /* Next header, unless done */
2654 /* Next header type unless done */
2656 if (yield == FAIL && *log_msgptr == NULL)
2657 *log_msgptr = US"there is no valid sender in any header line";
2659 if (yield == DEFER && *log_msgptr == NULL)
2660 *log_msgptr = US"all attempts to verify a sender in a header line deferred";
2668 /*************************************************
2669 * Get RFC 1413 identification *
2670 *************************************************/
2672 /* Attempt to get an id from the sending machine via the RFC 1413 protocol. If
2673 the timeout is set to zero, then the query is not done. There may also be lists
2674 of hosts and nets which are exempt. To guard against malefactors sending
2675 non-printing characters which could, for example, disrupt a message's headers,
2676 make sure the string consists of printing characters only.
2679 port the port to connect to; usually this is IDENT_PORT (113), but when
2680 running in the test harness with -bh a different value is used.
2684 Side effect: any received ident value is put in sender_ident (NULL otherwise)
2688 verify_get_ident(int port)
2690 client_conn_ctx ident_conn_ctx = {0};
2692 int received_sender_port, received_interface_port, n;
2695 uschar buffer[2048];
2697 /* Default is no ident. Check whether we want to do an ident check for this
2700 sender_ident = NULL;
2701 if (rfc1413_query_timeout <= 0 || verify_check_host(&rfc1413_hosts) != OK)
2704 DEBUG(D_ident) debug_printf("doing ident callback\n");
2706 /* Set up a connection to the ident port of the remote host. Bind the local end
2707 to the incoming interface address. If the sender host address is an IPv6
2708 address, the incoming interface address will also be IPv6. */
2710 host_af = Ustrchr(sender_host_address, ':') == NULL ? AF_INET : AF_INET6;
2711 if ((ident_conn_ctx.sock = ip_socket(SOCK_STREAM, host_af)) < 0) return;
2713 if (ip_bind(ident_conn_ctx.sock, host_af, interface_address, 0) < 0)
2715 DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n",
2720 /* Construct and send the query. */
2722 qlen = snprintf(CS buffer, sizeof(buffer), "%d , %d\r\n",
2723 sender_host_port, interface_port);
2724 early_data.data = buffer;
2725 early_data.len = qlen;
2727 /*XXX we trust that the query is idempotent */
2728 if (ip_connect(ident_conn_ctx.sock, host_af, sender_host_address, port,
2729 rfc1413_query_timeout, &early_data) < 0)
2731 if (errno == ETIMEDOUT && LOGGING(ident_timeout))
2732 log_write(0, LOG_MAIN, "ident connection to %s timed out",
2733 sender_host_address);
2735 DEBUG(D_ident) debug_printf("ident connection to %s failed: %s\n",
2736 sender_host_address, strerror(errno));
2740 /* Read a response line. We put it into the rest of the buffer, using several
2741 recv() calls if necessary. */
2749 int size = sizeof(buffer) - (p - buffer);
2751 if (size <= 0) goto END_OFF; /* Buffer filled without seeing \n. */
2752 count = ip_recv(&ident_conn_ctx, p, size, time(NULL) + rfc1413_query_timeout);
2753 if (count <= 0) goto END_OFF; /* Read error or EOF */
2755 /* Scan what we just read, to see if we have reached the terminating \r\n. Be
2756 generous, and accept a plain \n terminator as well. The only illegal
2759 for (pp = p; pp < p + count; pp++)
2761 if (*pp == 0) goto END_OFF; /* Zero octet not allowed */
2764 if (pp[-1] == '\r') pp--;
2766 goto GOT_DATA; /* Break out of both loops */
2770 /* Reached the end of the data without finding \n. Let the loop continue to
2771 read some more, if there is room. */
2778 /* We have received a line of data. Check it carefully. It must start with the
2779 same two port numbers that we sent, followed by data as defined by the RFC. For
2782 12345 , 25 : USERID : UNIX :root
2784 However, the amount of white space may be different to what we sent. In the
2785 "osname" field there may be several sub-fields, comma separated. The data we
2786 actually want to save follows the third colon. Some systems put leading spaces
2787 in it - we discard those. */
2789 if (sscanf(CS buffer + qlen, "%d , %d%n", &received_sender_port,
2790 &received_interface_port, &n) != 2 ||
2791 received_sender_port != sender_host_port ||
2792 received_interface_port != interface_port)
2795 p = buffer + qlen + n;
2796 while(isspace(*p)) p++;
2797 if (*p++ != ':') goto END_OFF;
2798 while(isspace(*p)) p++;
2799 if (Ustrncmp(p, "USERID", 6) != 0) goto END_OFF;
2801 while(isspace(*p)) p++;
2802 if (*p++ != ':') goto END_OFF;
2803 while (*p != 0 && *p != ':') p++;
2804 if (*p++ == 0) goto END_OFF;
2805 while(isspace(*p)) p++;
2806 if (*p == 0) goto END_OFF;
2808 /* The rest of the line is the data we want. We turn it into printing
2809 characters when we save it, so that it cannot mess up the format of any logging
2810 or Received: lines into which it gets inserted. We keep a maximum of 127
2811 characters. The deconst cast is ok as we fed a nonconst to string_printing() */
2813 sender_ident = US string_printing(string_copyn(p, 127));
2814 DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident);
2817 (void)close(ident_conn_ctx.sock);
2824 /*************************************************
2825 * Match host to a single host-list item *
2826 *************************************************/
2828 /* This function compares a host (name or address) against a single item
2829 from a host list. The host name gets looked up if it is needed and is not
2830 already known. The function is called from verify_check_this_host() via
2831 match_check_list(), which is why most of its arguments are in a single block.
2834 arg the argument block (see below)
2835 ss the host-list item
2836 valueptr where to pass back looked up data, or NULL
2837 error for error message when returning ERROR
2840 host_name (a) the host name, or
2841 (b) NULL, implying use sender_host_name and
2842 sender_host_aliases, looking them up if required, or
2843 (c) the empty string, meaning that only IP address matches
2845 host_address the host address
2846 host_ipv4 the IPv4 address taken from an IPv6 one
2850 DEFER lookup deferred
2851 ERROR (a) failed to find the host name or IP address, or
2852 (b) unknown lookup type specified, or
2853 (c) host name encountered when only IP addresses are
2858 check_host(void *arg, const uschar *ss, const uschar **valueptr, uschar **error)
2860 check_host_block *cb = (check_host_block *)arg;
2863 BOOL iplookup = FALSE;
2864 BOOL isquery = FALSE;
2865 BOOL isiponly = cb->host_name != NULL && cb->host_name[0] == 0;
2870 /* Optimize for the special case when the pattern is "*". */
2872 if (*ss == '*' && ss[1] == 0) return OK;
2874 /* If the pattern is empty, it matches only in the case when there is no host -
2875 this can occur in ACL checking for SMTP input using the -bs option. In this
2876 situation, the host address is the empty string. */
2878 if (cb->host_address[0] == 0) return (*ss == 0)? OK : FAIL;
2879 if (*ss == 0) return FAIL;
2881 /* If the pattern is precisely "@" then match against the primary host name,
2882 provided that host name matching is permitted; if it's "@[]" match against the
2883 local host's IP addresses. */
2889 if (isiponly) return ERROR;
2890 ss = primary_hostname;
2892 else if (Ustrcmp(ss, "@[]") == 0)
2894 for (ip_address_item * ip = host_find_interfaces(); ip; ip = ip->next)
2895 if (Ustrcmp(ip->address, cb->host_address) == 0) return OK;
2900 /* If the pattern is an IP address, optionally followed by a bitmask count, do
2901 a (possibly masked) comparison with the current IP address. */
2903 if (string_is_ip_address(ss, &maskoffset) != 0)
2904 return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL);
2906 /* The pattern is not an IP address. A common error that people make is to omit
2907 one component of an IPv4 address, either by accident, or believing that, for
2908 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,
2909 which it isn't. (Those applications that do accept 1.2.3 as an IP address
2910 interpret it as 1.2.0.3 because the final component becomes 16-bit - this is an
2911 ancient specification.) To aid in debugging these cases, we give a specific
2912 error if the pattern contains only digits and dots or contains a slash preceded
2913 only by digits and dots (a slash at the start indicates a file name and of
2914 course slashes may be present in lookups, but not preceded only by digits and
2917 for (t = ss; isdigit(*t) || *t == '.'; ) t++;
2918 if (*t == 0 || (*t == '/' && t != ss))
2920 *error = US"malformed IPv4 address or address mask";
2924 /* See if there is a semicolon in the pattern */
2926 semicolon = Ustrchr(ss, ';');
2928 /* If we are doing an IP address only match, then all lookups must be IP
2929 address lookups, even if there is no "net-". */
2933 iplookup = semicolon != NULL;
2936 /* Otherwise, if the item is of the form net[n]-lookup;<file|query> then it is
2937 a lookup on a masked IP network, in textual form. We obey this code even if we
2938 have already set iplookup, so as to skip over the "net-" prefix and to set the
2939 mask length. The net- stuff really only applies to single-key lookups where the
2940 key is implicit. For query-style lookups the key is specified in the query.
2941 From release 4.30, the use of net- for query style is no longer needed, but we
2942 retain it for backward compatibility. */
2944 if (Ustrncmp(ss, "net", 3) == 0 && semicolon != NULL)
2947 for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0';
2948 if (mlen == 0 && t == ss+3) mlen = -1; /* No mask supplied */
2949 iplookup = (*t++ == '-');
2954 /* Do the IP address lookup if that is indeed what we have */
2962 uschar *filename, *key, *result;
2965 /* Find the search type */
2967 search_type = search_findtype(t, semicolon - t);
2969 if (search_type < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
2970 search_error_message);
2972 /* Adjust parameters for the type of lookup. For a query-style lookup, there
2973 is no file name, and the "key" is just the query. For query-style with a file
2974 name, we have to fish the file off the start of the query. For a single-key
2975 lookup, the key is the current IP address, masked appropriately, and
2976 reconverted to text form, with the mask appended. For IPv6 addresses, specify
2977 dot separators instead of colons, except when the lookup type is "iplsearch".
2980 if (mac_islookup(search_type, lookup_absfilequery))
2982 filename = semicolon + 1;
2984 while (*key != 0 && !isspace(*key)) key++;
2985 filename = string_copyn(filename, key - filename);
2986 while (isspace(*key)) key++;
2988 else if (mac_islookup(search_type, lookup_querystyle))
2991 key = semicolon + 1;
2993 else /* Single-key style */
2995 int sep = (Ustrcmp(lookup_list[search_type]->name, "iplsearch") == 0)?
2997 insize = host_aton(cb->host_address, incoming);
2998 host_mask(insize, incoming, mlen);
2999 (void)host_nmtoa(insize, incoming, mlen, buffer, sep);
3001 filename = semicolon + 1;
3004 /* Now do the actual lookup; note that there is no search_close() because
3005 of the caching arrangements. */
3007 if (!(handle = search_open(filename, search_type, 0, NULL, NULL)))
3008 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s", search_error_message);
3010 result = search_find(handle, filename, key, -1, NULL, 0, 0, NULL);
3011 if (valueptr) *valueptr = result;
3012 return result ? OK : f.search_find_defer ? DEFER: FAIL;
3015 /* The pattern is not an IP address or network reference of any kind. That is,
3016 it is a host name pattern. If this is an IP only match, there's an error in the
3021 *error = US"cannot match host name in match_ip list";
3025 /* Check the characters of the pattern to see if they comprise only letters,
3026 digits, full stops, and hyphens (the constituents of domain names). Allow
3027 underscores, as they are all too commonly found. Sigh. Also, if
3028 allow_utf8_domains is set, allow top-bit characters. */
3030 for (t = ss; *t != 0; t++)
3031 if (!isalnum(*t) && *t != '.' && *t != '-' && *t != '_' &&
3032 (!allow_utf8_domains || *t < 128)) break;
3034 /* If the pattern is a complete domain name, with no fancy characters, look up
3035 its IP address and match against that. Note that a multi-homed host will add
3036 items to the chain. */
3047 /* Using byname rather than bydns here means we cannot determine dnssec
3048 status. On the other hand it is unclear how that could be either
3049 propagated up or enforced. */
3051 rc = host_find_byname(&h, NULL, HOST_FIND_QUALIFY_SINGLE, NULL, FALSE);
3052 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3054 for (host_item * hh = &h; hh; hh = hh->next)
3055 if (host_is_in_net(hh->address, cb->host_address, 0)) return OK;
3058 if (rc == HOST_FIND_AGAIN) return DEFER;
3059 *error = string_sprintf("failed to find IP address for %s", ss);
3063 /* Almost all subsequent comparisons require the host name, and can be done
3064 using the general string matching function. When this function is called for
3065 outgoing hosts, the name is always given explicitly. If it is NULL, it means we
3066 must use sender_host_name and its aliases, looking them up if necessary. */
3068 if (cb->host_name != NULL) /* Explicit host name given */
3069 return match_check_string(cb->host_name, ss, -1, TRUE, TRUE, TRUE,
3072 /* Host name not given; in principle we need the sender host name and its
3073 aliases. However, for query-style lookups, we do not need the name if the
3074 query does not contain $sender_host_name. From release 4.23, a reference to
3075 $sender_host_name causes it to be looked up, so we don't need to do the lookup
3078 if ((semicolon = Ustrchr(ss, ';')) != NULL)
3080 const uschar *affix;
3081 int partial, affixlen, starflags, id;
3084 id = search_findtype_partial(ss, &partial, &affix, &affixlen, &starflags);
3087 if (id < 0) /* Unknown lookup type */
3089 log_write(0, LOG_MAIN|LOG_PANIC, "%s in host list item \"%s\"",
3090 search_error_message, ss);
3093 isquery = mac_islookup(id, lookup_querystyle|lookup_absfilequery);
3098 switch(match_check_string(US"", ss, -1, TRUE, TRUE, TRUE, valueptr))
3101 case DEFER: return DEFER;
3102 default: return FAIL;
3106 /* Not a query-style lookup; must ensure the host name is present, and then we
3107 do a check on the name and all its aliases. */
3109 if (!sender_host_name)
3111 HDEBUG(D_host_lookup)
3112 debug_printf("sender host name required, to match against %s\n", ss);
3113 if (host_lookup_failed || host_name_lookup() != OK)
3115 *error = string_sprintf("failed to find host name for %s",
3116 sender_host_address);;
3119 host_build_sender_fullhost();
3122 /* Match on the sender host name, using the general matching function */
3124 switch(match_check_string(sender_host_name, ss, -1, TRUE, TRUE, TRUE, valueptr))
3127 case DEFER: return DEFER;
3130 /* If there are aliases, try matching on them. */
3132 aliases = sender_host_aliases;
3134 switch(match_check_string(*aliases++, ss, -1, TRUE, TRUE, TRUE, valueptr))
3137 case DEFER: return DEFER;
3145 /*************************************************
3146 * Check a specific host matches a host list *
3147 *************************************************/
3149 /* This function is passed a host list containing items in a number of
3150 different formats and the identity of a host. Its job is to determine whether
3151 the given host is in the set of hosts defined by the list. The host name is
3152 passed as a pointer so that it can be looked up if needed and not already
3153 known. This is commonly the case when called from verify_check_host() to check
3154 an incoming connection. When called from elsewhere the host name should usually
3157 This function is now just a front end to match_check_list(), which runs common
3158 code for scanning a list. We pass it the check_host() function to perform a
3162 listptr pointer to the host list
3163 cache_bits pointer to cache for named lists, or NULL
3164 host_name the host name or NULL, implying use sender_host_name and
3165 sender_host_aliases, looking them up if required
3166 host_address the IP address
3167 valueptr if not NULL, data from a lookup is passed back here
3169 Returns: OK if the host is in the defined set
3170 FAIL if the host is not in the defined set,
3171 DEFER if a data lookup deferred (not a host lookup)
3173 If the host name was needed in order to make a comparison, and could not be
3174 determined from the IP address, the result is FAIL unless the item
3175 "+allow_unknown" was met earlier in the list, in which case OK is returned. */
3178 verify_check_this_host(const uschar **listptr, unsigned int *cache_bits,
3179 const uschar *host_name, const uschar *host_address, const uschar **valueptr)
3182 unsigned int *local_cache_bits = cache_bits;
3183 const uschar *save_host_address = deliver_host_address;
3184 check_host_block cb = { .host_name = host_name, .host_address = host_address };
3186 if (valueptr) *valueptr = NULL;
3188 /* If the host address starts off ::ffff: it is an IPv6 address in
3189 IPv4-compatible mode. Find the IPv4 part for checking against IPv4
3192 cb.host_ipv4 = Ustrncmp(host_address, "::ffff:", 7) == 0
3193 ? host_address + 7 : host_address;
3195 /* During the running of the check, put the IP address into $host_address. In
3196 the case of calls from the smtp transport, it will already be there. However,
3197 in other calls (e.g. when testing ignore_target_hosts), it won't. Just to be on
3198 the safe side, any existing setting is preserved, though as I write this
3199 (November 2004) I can't see any cases where it is actually needed. */
3201 deliver_host_address = host_address;
3202 rc = match_check_list(
3203 listptr, /* the list */
3204 0, /* separator character */
3205 &hostlist_anchor, /* anchor pointer */
3206 &local_cache_bits, /* cache pointer */
3207 check_host, /* function for testing */
3208 &cb, /* argument for function */
3209 MCL_HOST, /* type of check */
3210 (host_address == sender_host_address)?
3211 US"host" : host_address, /* text for debugging */
3212 valueptr); /* where to pass back data */
3213 deliver_host_address = save_host_address;
3220 /*************************************************
3221 * Check the given host item matches a list *
3222 *************************************************/
3224 verify_check_given_host(const uschar **listptr, const host_item *host)
3226 return verify_check_this_host(listptr, NULL, host->name, host->address, NULL);
3229 /*************************************************
3230 * Check the remote host matches a list *
3231 *************************************************/
3233 /* This is a front end to verify_check_this_host(), created because checking
3234 the remote host is a common occurrence. With luck, a good compiler will spot
3235 the tail recursion and optimize it. If there's no host address, this is
3236 command-line SMTP input - check against an empty string for the address.
3239 listptr pointer to the host list
3241 Returns: the yield of verify_check_this_host(),
3242 i.e. OK, FAIL, or DEFER
3246 verify_check_host(uschar **listptr)
3248 return verify_check_this_host(CUSS listptr, sender_host_cache, NULL,
3249 sender_host_address ? sender_host_address : US"", NULL);
3256 /*************************************************
3257 * Invert an IP address *
3258 *************************************************/
3260 /* Originally just used for DNS xBL lists, now also used for the
3261 reverse_ip expansion operator.
3264 buffer where to put the answer
3265 address the address to invert
3269 invert_address(uschar *buffer, uschar *address)
3272 uschar *bptr = buffer;
3274 /* If this is an IPv4 address mapped into IPv6 format, adjust the pointer
3275 to the IPv4 part only. */
3277 if (Ustrncmp(address, "::ffff:", 7) == 0) address += 7;
3279 /* Handle IPv4 address: when HAVE_IPV6 is false, the result of host_aton() is
3282 if (host_aton(address, bin) == 1)
3285 for (int i = 0; i < 4; i++)
3287 sprintf(CS bptr, "%d.", x & 255);
3288 while (*bptr) bptr++;
3293 /* Handle IPv6 address. Actually, as far as I know, there are no IPv6 addresses
3294 in any DNS black lists, and the format in which they will be looked up is
3295 unknown. This is just a guess. */
3299 for (int j = 3; j >= 0; j--)
3302 for (int i = 0; i < 8; i++)
3304 sprintf(CS bptr, "%x.", x & 15);
3305 while (*bptr) bptr++;
3311 /* Remove trailing period -- this is needed so that both arbitrary
3312 dnsbl keydomains and inverted addresses may be combined with the
3313 same format string, "%s.%s" */
3320 /*************************************************
3321 * Perform a single dnsbl lookup *
3322 *************************************************/
3324 /* This function is called from verify_check_dnsbl() below. It is also called
3325 recursively from within itself when domain and domain_txt are different
3326 pointers, in order to get the TXT record from the alternate domain.
3329 domain the outer dnsbl domain
3330 domain_txt alternate domain to lookup TXT record on success; when the
3331 same domain is to be used, domain_txt == domain (that is,
3332 the pointers must be identical, not just the text)
3333 keydomain the current keydomain (for debug message)
3334 prepend subdomain to lookup (like keydomain, but
3335 reversed if IP address)
3336 iplist the list of matching IP addresses, or NULL for "any"
3337 bitmask true if bitmask matching is wanted
3338 match_type condition for 'succeed' result
3339 0 => Any RR in iplist (=)
3340 1 => No RR in iplist (!=)
3341 2 => All RRs in iplist (==)
3342 3 => Some RRs not in iplist (!==)
3343 the two bits are defined as MT_NOT and MT_ALL
3344 defer_return what to return for a defer
3346 Returns: OK if lookup succeeded
3351 one_check_dnsbl(uschar *domain, uschar *domain_txt, uschar *keydomain,
3352 uschar *prepend, uschar *iplist, BOOL bitmask, int match_type,
3358 dnsbl_cache_block *cb;
3359 int old_pool = store_pool;
3360 uschar query[256]; /* DNS domain max length */
3362 /* Construct the specific query domainname */
3364 if (!string_format(query, sizeof(query), "%s.%s", prepend, domain))
3366 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
3367 "(ignored): %s...", query);
3371 /* Look for this query in the cache. */
3373 if ( (t = tree_search(dnsbl_cache, query))
3374 && (cb = t->data.ptr)->expiry > time(NULL)
3377 /* Previous lookup was cached */
3380 HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
3383 /* If not cached from a previous lookup, we must do a DNS lookup, and
3384 cache the result in permanent memory. */
3390 store_pool = POOL_PERM;
3394 HDEBUG(D_dnsbl) debug_printf("cached data found but past valid time; ");
3398 { /* Set up a tree entry to cache the lookup */
3399 t = store_get(sizeof(tree_node) + Ustrlen(query));
3400 Ustrcpy(t->name, query);
3401 t->data.ptr = cb = store_get(sizeof(dnsbl_cache_block));
3402 (void)tree_insertnode(&dnsbl_cache, t);
3405 /* Do the DNS lookup . */
3407 HDEBUG(D_dnsbl) debug_printf("new DNS lookup for %s\n", query);
3408 cb->rc = dns_basic_lookup(&dnsa, query, T_A);
3409 cb->text_set = FALSE;
3413 /* If the lookup succeeded, cache the RHS address. The code allows for
3414 more than one address - this was for complete generality and the possible
3415 use of A6 records. However, A6 records are no longer supported. Leave the code
3418 Quite apart from one A6 RR generating multiple addresses, there are DNS
3419 lists that return more than one A record, so we must handle multiple
3420 addresses generated in that way as well.
3422 Mark the cache entry with the "now" plus the minimum of the address TTLs,
3423 or some suitably far-future time if none were found. */
3425 if (cb->rc == DNS_SUCCEED)
3427 dns_address ** addrp = &(cb->rhs);
3428 for (dns_record * rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); rr;
3429 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3430 if (rr->type == T_A)
3432 dns_address *da = dns_address_from_rr(&dnsa, rr);
3436 while (da->next) da = da->next;
3438 if (ttl > rr->ttl) ttl = rr->ttl;
3442 /* If we didn't find any A records, change the return code. This can
3443 happen when there is a CNAME record but there are no A records for what
3446 if (!cb->rhs) cb->rc = DNS_NODATA;
3449 cb->expiry = time(NULL)+ttl;
3450 store_pool = old_pool;
3453 /* We now have the result of the DNS lookup, either newly done, or cached
3454 from a previous call. If the lookup succeeded, check against the address
3455 list if there is one. This may be a positive equality list (introduced by
3456 "="), a negative equality list (introduced by "!="), a positive bitmask
3457 list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/
3459 if (cb->rc == DNS_SUCCEED)
3461 dns_address *da = NULL;
3462 uschar *addlist = cb->rhs->address;
3464 /* For A and AAAA records, there may be multiple addresses from multiple
3465 records. For A6 records (currently not expected to be used) there may be
3466 multiple addresses from a single record. */
3468 for (da = cb->rhs->next; da; da = da->next)
3469 addlist = string_sprintf("%s, %s", addlist, da->address);
3471 HDEBUG(D_dnsbl) debug_printf("DNS lookup for %s succeeded (yielding %s)\n",
3474 /* Address list check; this can be either for equality, or via a bitmask.
3475 In the latter case, all the bits must match. */
3479 for (da = cb->rhs; da; da = da->next)
3483 const uschar *ptr = iplist;
3486 /* Handle exact matching */
3490 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))))
3491 if (Ustrcmp(CS da->address, ip) == 0)
3495 /* Handle bitmask matching */
3502 /* At present, all known DNS blocking lists use A records, with
3503 IPv4 addresses on the RHS encoding the information they return. I
3504 wonder if this will linger on as the last vestige of IPv4 when IPv6
3505 is ubiquitous? Anyway, for now we use paranoia code to completely
3506 ignore IPv6 addresses. The default mask is 0, which always matches.
3507 We change this only for IPv4 addresses in the list. */
3509 if (host_aton(da->address, address) == 1) mask = address[0];
3511 /* Scan the returned addresses, skipping any that are IPv6 */
3513 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))))
3515 if (host_aton(ip, address) != 1) continue;
3516 if ((address[0] & mask) == address[0]) break;
3522 (a) An IP address in an any ('=') list matched, or
3523 (b) No IP address in an all ('==') list matched
3525 then we're done searching. */
3527 if (((match_type & MT_ALL) != 0) == (res == NULL)) break;
3530 /* If da == NULL, either
3532 (a) No IP address in an any ('=') list matched, or
3533 (b) An IP address in an all ('==') list didn't match
3535 so behave as if the DNSBL lookup had not succeeded, i.e. the host is not on
3538 if ((match_type == MT_NOT || match_type == MT_ALL) != (da == NULL))
3546 res = US"was no match"; break;
3548 res = US"was an exclude match"; break;
3550 res = US"was an IP address that did not match"; break;
3552 res = US"were no IP addresses that did not match"; break;
3554 debug_printf("=> but we are not accepting this block class because\n");
3555 debug_printf("=> there %s for %s%c%s\n",
3557 ((match_type & MT_ALL) == 0)? "" : "=",
3558 bitmask? '&' : '=', iplist);
3564 /* Either there was no IP list, or the record matched, implying that the
3565 domain is on the list. We now want to find a corresponding TXT record. If an
3566 alternate domain is specified for the TXT record, call this function
3567 recursively to look that up; this has the side effect of re-checking that
3568 there is indeed an A record at the alternate domain. */
3570 if (domain_txt != domain)
3571 return one_check_dnsbl(domain_txt, domain_txt, keydomain, prepend, NULL,
3572 FALSE, match_type, defer_return);
3574 /* If there is no alternate domain, look up a TXT record in the main domain
3575 if it has not previously been cached. */
3579 cb->text_set = TRUE;
3580 if (dns_basic_lookup(&dnsa, query, T_TXT) == DNS_SUCCEED)
3581 for (dns_record * rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); rr;
3582 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3583 if (rr->type == T_TXT)
3585 int len = (rr->data)[0];
3586 if (len > 511) len = 127;
3587 store_pool = POOL_PERM;
3588 cb->text = string_sprintf("%.*s", len, CUS (rr->data+1));
3589 store_pool = old_pool;
3594 dnslist_value = addlist;
3595 dnslist_text = cb->text;
3599 /* There was a problem with the DNS lookup */
3601 if (cb->rc != DNS_NOMATCH && cb->rc != DNS_NODATA)
3603 log_write(L_dnslist_defer, LOG_MAIN,
3604 "DNS list lookup defer (probably timeout) for %s: %s", query,
3605 (defer_return == OK)? US"assumed in list" :
3606 (defer_return == FAIL)? US"assumed not in list" :
3607 US"returned DEFER");
3608 return defer_return;
3611 /* No entry was found in the DNS; continue for next domain */
3615 debug_printf("DNS lookup for %s failed\n", query);
3616 debug_printf("=> that means %s is not listed at %s\n",
3626 /*************************************************
3627 * Check host against DNS black lists *
3628 *************************************************/
3630 /* This function runs checks against a list of DNS black lists, until one
3631 matches. Each item on the list can be of the form
3633 domain=ip-address/key
3635 The domain is the right-most domain that is used for the query, for example,
3636 blackholes.mail-abuse.org. If the IP address is present, there is a match only
3637 if the DNS lookup returns a matching IP address. Several addresses may be
3638 given, comma-separated, for example: x.y.z=127.0.0.1,127.0.0.2.
3640 If no key is given, what is looked up in the domain is the inverted IP address
3641 of the current client host. If a key is given, it is used to construct the
3642 domain for the lookup. For example:
3644 dsn.rfc-ignorant.org/$sender_address_domain
3646 After finding a match in the DNS, the domain is placed in $dnslist_domain, and
3647 then we check for a TXT record for an error message, and if found, save its
3648 value in $dnslist_text. We also cache everything in a tree, to optimize
3651 The TXT record is normally looked up in the same domain as the A record, but
3652 when many lists are combined in a single DNS domain, this will not be a very
3653 specific message. It is possible to specify a different domain for looking up
3654 TXT records; this is given before the main domain, comma-separated. For
3657 dnslists = http.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.2 : \
3658 socks.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.3
3660 The caching ensures that only one lookup in dnsbl.sorbs.net is done.
3662 Note: an address for testing RBL is 192.203.178.39
3663 Note: an address for testing DUL is 192.203.178.4
3664 Note: a domain for testing RFCI is example.tld.dsn.rfc-ignorant.org
3668 listptr the domain/address/data list
3669 log_msgptr log message on error
3671 Returns: OK successful lookup (i.e. the address is on the list), or
3672 lookup deferred after +include_unknown
3673 FAIL name not found, or no data found for the given type, or
3674 lookup deferred after +exclude_unknown (default)
3675 DEFER lookup failure, if +defer_unknown was set
3679 verify_check_dnsbl(int where, const uschar ** listptr, uschar ** log_msgptr)
3682 int defer_return = FAIL;
3683 const uschar *list = *listptr;
3685 uschar buffer[1024];
3686 uschar revadd[128]; /* Long enough for IPv6 address */
3688 /* Indicate that the inverted IP address is not yet set up */
3692 /* In case this is the first time the DNS resolver is being used. */
3694 dns_init(FALSE, FALSE, FALSE); /*XXX dnssec? */
3696 /* Loop through all the domains supplied, until something matches */
3698 while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
3701 BOOL bitmask = FALSE;
3708 HDEBUG(D_dnsbl) debug_printf("DNS list check: %s\n", domain);
3710 /* Deal with special values that change the behaviour on defer */
3712 if (domain[0] == '+')
3714 if (strcmpic(domain, US"+include_unknown") == 0) defer_return = OK;
3715 else if (strcmpic(domain, US"+exclude_unknown") == 0) defer_return = FAIL;
3716 else if (strcmpic(domain, US"+defer_unknown") == 0) defer_return = DEFER;
3718 log_write(0, LOG_MAIN|LOG_PANIC, "unknown item in dnslist (ignored): %s",
3723 /* See if there's explicit data to be looked up */
3725 if ((key = Ustrchr(domain, '/'))) *key++ = 0;
3727 /* See if there's a list of addresses supplied after the domain name. This is
3728 introduced by an = or a & character; if preceded by = we require all matches
3729 and if preceded by ! we invert the result. */
3731 if (!(iplist = Ustrchr(domain, '=')))
3734 iplist = Ustrchr(domain, '&');
3737 if (iplist) /* Found either = or & */
3739 if (iplist > domain && iplist[-1] == '!') /* Handle preceding ! */
3741 match_type |= MT_NOT;
3745 *iplist++ = 0; /* Terminate domain, move on */
3747 /* If we found = (bitmask == FALSE), check for == or =& */
3749 if (!bitmask && (*iplist == '=' || *iplist == '&'))
3751 bitmask = *iplist++ == '&';
3752 match_type |= MT_ALL;
3757 /* If there is a comma in the domain, it indicates that a second domain for
3758 looking up TXT records is provided, before the main domain. Otherwise we must
3759 set domain_txt == domain. */
3761 domain_txt = domain;
3762 comma = Ustrchr(domain, ',');
3769 /* Check that what we have left is a sensible domain name. There is no reason
3770 why these domains should in fact use the same syntax as hosts and email
3771 domains, but in practice they seem to. However, there is little point in
3772 actually causing an error here, because that would no doubt hold up incoming
3773 mail. Instead, I'll just log it. */
3775 for (uschar * s = domain; *s; s++)
3776 if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_')
3778 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
3779 "strange characters - is this right?", domain);
3783 /* Check the alternate domain if present */
3785 if (domain_txt != domain) for (uschar * s = domain_txt; *s; s++)
3786 if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_')
3788 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
3789 "strange characters - is this right?", domain_txt);
3793 /* If there is no key string, construct the query by adding the domain name
3794 onto the inverted host address, and perform a single DNS lookup. */
3798 if (where == ACL_WHERE_NOTSMTP_START || where == ACL_WHERE_NOTSMTP)
3800 *log_msgptr = string_sprintf
3801 ("cannot test auto-keyed dnslists condition in %s ACL",
3802 acl_wherenames[where]);
3805 if (sender_host_address == NULL) return FAIL; /* can never match */
3806 if (revadd[0] == 0) invert_address(revadd, sender_host_address);
3807 rc = one_check_dnsbl(domain, domain_txt, sender_host_address, revadd,
3808 iplist, bitmask, match_type, defer_return);
3811 dnslist_domain = string_copy(domain_txt);
3812 dnslist_matched = string_copy(sender_host_address);
3813 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
3814 sender_host_address, dnslist_domain);
3816 if (rc != FAIL) return rc; /* OK or DEFER */
3819 /* If there is a key string, it can be a list of domains or IP addresses to
3820 be concatenated with the main domain. */
3827 uschar keybuffer[256];
3828 uschar keyrevadd[128];
3830 while ((keydomain = string_nextinlist(CUSS &key, &keysep, keybuffer,
3831 sizeof(keybuffer))) != NULL)
3833 uschar *prepend = keydomain;
3835 if (string_is_ip_address(keydomain, NULL) != 0)
3837 invert_address(keyrevadd, keydomain);
3838 prepend = keyrevadd;
3841 rc = one_check_dnsbl(domain, domain_txt, keydomain, prepend, iplist,
3842 bitmask, match_type, defer_return);
3846 dnslist_domain = string_copy(domain_txt);
3847 dnslist_matched = string_copy(keydomain);
3848 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
3849 keydomain, dnslist_domain);
3853 /* If the lookup deferred, remember this fact. We keep trying the rest
3854 of the list to see if we get a useful result, and if we don't, we return
3855 DEFER at the end. */
3857 if (rc == DEFER) defer = TRUE;
3858 } /* continue with next keystring domain/address */
3860 if (defer) return DEFER;
3862 } /* continue with next dnsdb outer domain */
3869 /* End of verify.c */