1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2014 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions concerned with verifying things. The original code for callout
9 caching was contributed by Kevin Fleming (but I hacked it around a bit). */
13 #include "transports/smtp.h"
15 #define CUTTHROUGH_CMD_TIMEOUT 30 /* timeout for cutthrough-routing calls */
16 #define CUTTHROUGH_DATA_TIMEOUT 60 /* timeout for cutthrough-routing calls */
17 static smtp_outblock ctblock;
18 uschar ctbuffer[8192];
21 /* Structure for caching DNSBL lookups */
23 typedef struct dnsbl_cache_block {
31 /* Anchor for DNSBL cache */
33 static tree_node *dnsbl_cache = NULL;
36 /* Bits for match_type in one_check_dnsbl() */
41 static uschar cutthrough_response(char, uschar **);
44 /*************************************************
45 * Retrieve a callout cache record *
46 *************************************************/
48 /* If a record exists, check whether it has expired.
51 dbm_file an open hints file
53 type "address" or "domain"
54 positive_expire expire time for positive records
55 negative_expire expire time for negative records
57 Returns: the cache record if a non-expired one exists, else NULL
60 static dbdata_callout_cache *
61 get_callout_cache_record(open_db *dbm_file, const uschar *key, uschar *type,
62 int positive_expire, int negative_expire)
67 dbdata_callout_cache *cache_record;
69 cache_record = dbfn_read_with_length(dbm_file, key, &length);
71 if (cache_record == NULL)
73 HDEBUG(D_verify) debug_printf("callout cache: no %s record found\n", type);
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\n", type);
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\n", type);
120 /*************************************************
121 * Do callout verification for an address *
122 *************************************************/
124 /* This function is called from verify_address() when the address has routed to
125 a host list, and a callout has been requested. Callouts are expensive; that is
126 why a cache is used to improve the efficiency.
129 addr the address that's been routed
130 host_list the list of hosts to try
131 tf the transport feedback block
133 ifstring "interface" option from transport, or NULL
134 portstring "port" option from transport, or NULL
135 protocolstring "protocol" option from transport, or NULL
136 callout the per-command callout timeout
137 callout_overall the overall callout timeout (if < 0 use 4*callout)
138 callout_connect the callout connection timeout (if < 0 use callout)
139 options the verification options - these bits are used:
140 vopt_is_recipient => this is a recipient address
141 vopt_callout_no_cache => don't use callout cache
142 vopt_callout_fullpm => if postmaster check, do full one
143 vopt_callout_random => do the "random" thing
144 vopt_callout_recipsender => use real sender for recipient
145 vopt_callout_recippmaster => use postmaster for recipient
146 se_mailfrom MAIL FROM address for sender verify; NULL => ""
147 pm_mailfrom if non-NULL, do the postmaster check with this sender
149 Returns: OK/FAIL/DEFER
153 do_callout(address_item *addr, host_item *host_list, transport_feedback *tf,
154 int callout, int callout_overall, int callout_connect, int options,
155 uschar *se_mailfrom, uschar *pm_mailfrom)
157 BOOL is_recipient = (options & vopt_is_recipient) != 0;
158 BOOL callout_no_cache = (options & vopt_callout_no_cache) != 0;
159 BOOL callout_random = (options & vopt_callout_random) != 0;
162 int old_domain_cache_result = ccache_accept;
165 uschar *from_address;
166 uschar *random_local_part = NULL;
167 const uschar *save_deliver_domain = deliver_domain;
168 uschar **failure_ptr = is_recipient?
169 &recipient_verify_failure : &sender_verify_failure;
171 open_db *dbm_file = NULL;
172 dbdata_callout_cache new_domain_record;
173 dbdata_callout_cache_address new_address_record;
175 time_t callout_start_time;
177 new_domain_record.result = ccache_unknown;
178 new_domain_record.postmaster_result = ccache_unknown;
179 new_domain_record.random_result = ccache_unknown;
181 memset(&new_address_record, 0, sizeof(new_address_record));
183 /* For a recipient callout, the key used for the address cache record must
184 include the sender address if we are using the real sender in the callout,
185 because that may influence the result of the callout. */
187 address_key = addr->address;
192 if (options & vopt_callout_recipsender)
194 address_key = string_sprintf("%s/<%s>", addr->address, sender_address);
195 from_address = sender_address;
197 else if (options & vopt_callout_recippmaster)
199 address_key = string_sprintf("%s/<postmaster@%s>", addr->address,
200 qualify_domain_sender);
201 from_address = string_sprintf("postmaster@%s", qualify_domain_sender);
205 /* For a sender callout, we must adjust the key if the mailfrom address is not
210 from_address = (se_mailfrom == NULL)? US"" : se_mailfrom;
211 if (from_address[0] != 0)
212 address_key = string_sprintf("%s/<%s>", addr->address, from_address);
215 /* Open the callout cache database, it it exists, for reading only at this
216 stage, unless caching has been disabled. */
218 if (callout_no_cache)
220 HDEBUG(D_verify) debug_printf("callout cache: disabled by no_cache\n");
222 else if ((dbm_file = dbfn_open(US"callout", O_RDWR, &dbblock, FALSE)) == NULL)
224 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
227 /* If a cache database is available see if we can avoid the need to do an
228 actual callout by making use of previously-obtained data. */
230 if (dbm_file != NULL)
232 dbdata_callout_cache_address *cache_address_record;
233 dbdata_callout_cache *cache_record = get_callout_cache_record(dbm_file,
234 addr->domain, US"domain",
235 callout_cache_domain_positive_expire,
236 callout_cache_domain_negative_expire);
238 /* If an unexpired cache record was found for this domain, see if the callout
239 process can be short-circuited. */
241 if (cache_record != NULL)
243 /* In most cases, if an early command (up to and including MAIL FROM:<>)
244 was rejected, there is no point carrying on. The callout fails. However, if
245 we are doing a recipient verification with use_sender or use_postmaster
246 set, a previous failure of MAIL FROM:<> doesn't count, because this time we
247 will be using a non-empty sender. We have to remember this situation so as
248 not to disturb the cached domain value if this whole verification succeeds
249 (we don't want it turning into "accept"). */
251 old_domain_cache_result = cache_record->result;
253 if (cache_record->result == ccache_reject ||
254 (*from_address == 0 && cache_record->result == ccache_reject_mfnull))
256 setflag(addr, af_verify_nsfail);
258 debug_printf("callout cache: domain gave initial rejection, or "
259 "does not accept HELO or MAIL FROM:<>\n");
260 setflag(addr, af_verify_nsfail);
261 addr->user_message = US"(result of an earlier callout reused).";
263 *failure_ptr = US"mail";
267 /* If a previous check on a "random" local part was accepted, we assume
268 that the server does not do any checking on local parts. There is therefore
269 no point in doing the callout, because it will always be successful. If a
270 random check previously failed, arrange not to do it again, but preserve
271 the data in the new record. If a random check is required but hasn't been
272 done, skip the remaining cache processing. */
274 if (callout_random) switch(cache_record->random_result)
278 debug_printf("callout cache: domain accepts random addresses\n");
279 goto END_CALLOUT; /* Default yield is OK */
283 debug_printf("callout cache: domain rejects random addresses\n");
284 callout_random = FALSE;
285 new_domain_record.random_result = ccache_reject;
286 new_domain_record.random_stamp = cache_record->random_stamp;
291 debug_printf("callout cache: need to check random address handling "
292 "(not cached or cache expired)\n");
296 /* If a postmaster check is requested, but there was a previous failure,
297 there is again no point in carrying on. If a postmaster check is required,
298 but has not been done before, we are going to have to do a callout, so skip
299 remaining cache processing. */
301 if (pm_mailfrom != NULL)
303 if (cache_record->postmaster_result == ccache_reject)
305 setflag(addr, af_verify_pmfail);
307 debug_printf("callout cache: domain does not accept "
308 "RCPT TO:<postmaster@domain>\n");
310 *failure_ptr = US"postmaster";
311 setflag(addr, af_verify_pmfail);
312 addr->user_message = US"(result of earlier verification reused).";
315 if (cache_record->postmaster_result == ccache_unknown)
318 debug_printf("callout cache: need to check RCPT "
319 "TO:<postmaster@domain> (not cached or cache expired)\n");
323 /* If cache says OK, set pm_mailfrom NULL to prevent a redundant
324 postmaster check if the address itself has to be checked. Also ensure
325 that the value in the cache record is preserved (with its old timestamp).
328 HDEBUG(D_verify) debug_printf("callout cache: domain accepts RCPT "
329 "TO:<postmaster@domain>\n");
331 new_domain_record.postmaster_result = ccache_accept;
332 new_domain_record.postmaster_stamp = cache_record->postmaster_stamp;
336 /* We can't give a result based on information about the domain. See if there
337 is an unexpired cache record for this specific address (combined with the
338 sender address if we are doing a recipient callout with a non-empty sender).
341 cache_address_record = (dbdata_callout_cache_address *)
342 get_callout_cache_record(dbm_file,
343 address_key, US"address",
344 callout_cache_positive_expire,
345 callout_cache_negative_expire);
347 if (cache_address_record != NULL)
349 if (cache_address_record->result == ccache_accept)
352 debug_printf("callout cache: address record is positive\n");
357 debug_printf("callout cache: address record is negative\n");
358 addr->user_message = US"Previous (cached) callout verification failure";
359 *failure_ptr = US"recipient";
365 /* Close the cache database while we actually do the callout for real. */
368 dbfn_close(dbm_file);
372 if (!addr->transport)
374 HDEBUG(D_verify) debug_printf("cannot callout via null transport\n");
376 else if (Ustrcmp(addr->transport->driver_name, "smtp") != 0)
377 log_write(0, LOG_MAIN|LOG_PANIC|LOG_CONFIG_FOR, "callout transport '%s': %s is non-smtp",
378 addr->transport->name, addr->transport->driver_name);
381 smtp_transport_options_block *ob =
382 (smtp_transport_options_block *)addr->transport->options_block;
384 /* The information wasn't available in the cache, so we have to do a real
385 callout and save the result in the cache for next time, unless no_cache is set,
386 or unless we have a previously cached negative random result. If we are to test
387 with a random local part, ensure that such a local part is available. If not,
388 log the fact, but carry on without randomming. */
390 if (callout_random && callout_random_local_part != NULL)
391 if (!(random_local_part = expand_string(callout_random_local_part)))
392 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand "
393 "callout_random_local_part: %s", expand_string_message);
395 /* Default the connect and overall callout timeouts if not set, and record the
396 time we are starting so that we can enforce it. */
398 if (callout_overall < 0) callout_overall = 4 * callout;
399 if (callout_connect < 0) callout_connect = callout;
400 callout_start_time = time(NULL);
402 /* Before doing a real callout, if this is an SMTP connection, flush the SMTP
403 output because a callout might take some time. When PIPELINING is active and
404 there are many recipients, the total time for doing lots of callouts can add up
405 and cause the client to time out. So in this case we forgo the PIPELINING
408 if (smtp_out != NULL && !disable_callout_flush) mac_smtp_fflush();
410 /* cutthrough-multi: if a nonfirst rcpt has the same routing as the first,
411 and we are holding a cutthrough conn open, we can just append the rcpt to
412 that conn for verification purposes (and later delivery also). Simplest
413 coding means skipping this whole loop and doing the append separately.
415 We will need to remember it has been appended so that rcpt-acl tail code
416 can do it there for the non-rcpt-verify case. For this we keep an addresscount.
419 /* Can we re-use an open cutthrough connection? */
420 if ( cutthrough.fd >= 0
421 && (options & (vopt_callout_recipsender | vopt_callout_recippmaster))
422 == vopt_callout_recipsender
423 && !random_local_part
427 if (addr->transport == cutthrough.addr.transport)
428 for (host = host_list; host; host = host->next)
429 if (Ustrcmp(host->address, cutthrough.host.address) == 0)
432 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
435 deliver_host = host->name;
436 deliver_host_address = host->address;
437 deliver_host_port = host->port;
438 deliver_domain = addr->domain;
439 transport_name = addr->transport->name;
441 host_af = (Ustrchr(host->address, ':') == NULL)? AF_INET:AF_INET6;
443 if (!smtp_get_interface(tf->interface, host_af, addr, NULL, &interface,
445 !smtp_get_port(tf->port, addr, &port, US"callout"))
446 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
449 if ( ( interface == cutthrough.interface
451 && cutthrough.interface
452 && Ustrcmp(interface, cutthrough.interface) == 0
454 && port == cutthrough.host.port
459 /* Match! Send the RCPT TO, append the addr, set done */
461 smtp_write_command(&ctblock, FALSE, "RCPT TO:<%.1000s>\r\n",
462 transport_rcpt_address(addr,
463 (addr->transport == NULL)? FALSE :
464 addr->transport->rcpt_include_affixes)) >= 0 &&
465 cutthrough_response('2', &resp) == '2';
467 /* This would go horribly wrong if a callout fail was ignored by ACL.
468 We punt by abandoning cutthrough on a reject, like the
473 address_item * na = store_get(sizeof(address_item));
474 *na = cutthrough.addr;
475 cutthrough.addr = *addr;
476 cutthrough.addr.host_used = &cutthrough.host;
477 cutthrough.addr.next = na;
483 cancel_cutthrough_connection("recipient rejected");
484 if (errno == ETIMEDOUT)
486 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
491 Ustrcpy(resp, US"connection dropped");
494 string_sprintf("response to \"%s\" from %s [%s] was: %s",
495 big_buffer, host->name, host->address,
496 string_printing(resp));
499 string_sprintf("Callout verification failed:\n%s", resp);
501 /* Hard rejection ends the process */
503 if (resp[0] == '5') /* Address rejected */
514 cancel_cutthrough_connection("incompatible connection");
517 /* Now make connections to the hosts and do real callouts. The list of hosts
518 is passed in as an argument. */
520 for (host = host_list; host != NULL && !done; host = host->next)
522 smtp_inblock inblock;
523 smtp_outblock outblock;
526 BOOL send_quit = TRUE;
527 uschar *active_hostname = smtp_active_hostname;
531 BOOL suppress_tls = FALSE;
532 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
533 #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_DANE)
536 dns_answer tlsa_dnsa;
538 uschar inbuffer[4096];
539 uschar outbuffer[1024];
540 uschar responsebuffer[4096];
542 clearflag(addr, af_verify_pmfail); /* postmaster callout flag */
543 clearflag(addr, af_verify_nsfail); /* null sender callout flag */
545 /* Skip this host if we don't have an IP address for it. */
547 if (host->address == NULL)
549 DEBUG(D_verify) debug_printf("no IP address for host name %s: skipping\n",
554 /* Check the overall callout timeout */
556 if (time(NULL) - callout_start_time >= callout_overall)
558 HDEBUG(D_verify) debug_printf("overall timeout for callout exceeded\n");
562 /* Set IPv4 or IPv6 */
564 host_af = (Ustrchr(host->address, ':') == NULL)? AF_INET:AF_INET6;
566 /* Expand and interpret the interface and port strings. The latter will not
567 be used if there is a host-specific port (e.g. from a manualroute router).
568 This has to be delayed till now, because they may expand differently for
569 different hosts. If there's a failure, log it, but carry on with the
572 deliver_host = host->name;
573 deliver_host_address = host->address;
574 deliver_host_port = host->port;
575 deliver_domain = addr->domain;
576 transport_name = addr->transport->name;
578 if (!smtp_get_interface(tf->interface, host_af, addr, NULL, &interface,
580 !smtp_get_port(tf->port, addr, &port, US"callout"))
581 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
584 /* Set HELO string according to the protocol */
585 lmtp= Ustrcmp(tf->protocol, "lmtp") == 0;
586 smtps= Ustrcmp(tf->protocol, "smtps") == 0;
589 HDEBUG(D_verify) debug_printf("interface=%s port=%d\n", interface, port);
591 #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_DANE)
595 tls_out.dane_verified = FALSE;
596 tls_out.tlsa_usage = 0;
599 verify_check_given_host(&ob->hosts_require_dane, host) == OK;
601 if (host->dnssec == DS_YES)
604 || verify_check_given_host(&ob->hosts_try_dane, host) == OK
606 if ((rc = tlsa_lookup(host, &tlsa_dnsa, dane_required, &dane)) != OK)
609 else if (dane_required)
611 log_write(0, LOG_MAIN, "DANE error: %s lookup not DNSSEC", host->name);
616 ob->tls_tempfail_tryclear = FALSE;
620 /* Set up the buffer for reading SMTP response packets. */
622 inblock.buffer = inbuffer;
623 inblock.buffersize = sizeof(inbuffer);
624 inblock.ptr = inbuffer;
625 inblock.ptrend = inbuffer;
627 /* Set up the buffer for holding SMTP commands while pipelining */
629 outblock.buffer = outbuffer;
630 outblock.buffersize = sizeof(outbuffer);
631 outblock.ptr = outbuffer;
632 outblock.cmd_count = 0;
633 outblock.authenticating = FALSE;
635 /* Connect to the host; on failure, just loop for the next one, but we
636 set the error for the last one. Use the callout_connect timeout. */
638 tls_retry_connection:
640 /* Reset the parameters of a TLS session */
641 tls_out.cipher = tls_out.peerdn = tls_out.peercert = NULL;
643 inblock.sock = outblock.sock =
644 smtp_connect(host, host_af, port, interface, callout_connect, TRUE, NULL
645 #ifdef EXPERIMENTAL_EVENT
646 /*XXX event action? NULL for now. */
650 /* reconsider DSCP here */
651 if (inblock.sock < 0)
653 addr->message = string_sprintf("could not connect to %s [%s]: %s",
654 host->name, host->address, strerror(errno));
655 transport_name = NULL;
656 deliver_host = deliver_host_address = NULL;
657 deliver_domain = save_deliver_domain;
661 /* Expand the helo_data string to find the host name to use. */
663 if (tf->helo_data != NULL)
665 uschar *s = expand_string(tf->helo_data);
667 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: failed to expand transport's "
668 "helo_data value for callout: %s", addr->address,
669 expand_string_message);
670 else active_hostname = s;
673 /* Wait for initial response, and send HELO. The smtp_write_command()
674 function leaves its command in big_buffer. This is used in error responses.
675 Initialize it in case the connection is rejected. */
677 Ustrcpy(big_buffer, "initial connection");
679 /* Unless ssl-on-connect, wait for the initial greeting */
683 if (!smtps || (smtps && tls_out.active >= 0))
686 if (!(done= smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), '2', callout)))
687 goto RESPONSE_FAILED;
689 #ifdef EXPERIMENTAL_EVENT
690 lookup_dnssec_authenticated = host->dnssec==DS_YES ? US"yes"
691 : host->dnssec==DS_NO ? US"no" : NULL;
692 if (event_raise(addr->transport->event_action,
693 US"smtp:connect", responsebuffer))
695 lookup_dnssec_authenticated = NULL;
696 /* Logging? Debug? */
697 goto RESPONSE_FAILED;
699 lookup_dnssec_authenticated = NULL;
703 /* Not worth checking greeting line for ESMTP support */
704 if (!(esmtp = verify_check_given_host(&ob->hosts_avoid_esmtp, host) != OK))
706 debug_printf("not sending EHLO (host matches hosts_avoid_esmtp)\n");
711 if (smtps && tls_out.active < 0) /* ssl-on-connect, first pass */
714 ob->tls_tempfail_tryclear = FALSE;
716 else /* all other cases */
721 if (!(done= smtp_write_command(&outblock, FALSE, "%s %s\r\n",
722 !esmtp? "HELO" : lmtp? "LHLO" : "EHLO", active_hostname) >= 0))
724 if (!smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), '2', callout))
726 if (errno != 0 || responsebuffer[0] == 0 || lmtp || !esmtp || tls_out.active >= 0)
729 goto RESPONSE_FAILED;
735 goto esmtp_retry; /* fallback to HELO */
738 /* Set tls_offered if the response to EHLO specifies support for STARTTLS. */
740 if (esmtp && !suppress_tls && tls_out.active < 0)
742 if (regex_STARTTLS == NULL) regex_STARTTLS =
743 regex_must_compile(US"\\n250[\\s\\-]STARTTLS(\\s|\\n|$)", FALSE, TRUE);
745 tls_offered = pcre_exec(regex_STARTTLS, NULL, CS responsebuffer,
746 Ustrlen(responsebuffer), 0, PCRE_EOPT, NULL, 0) >= 0;
753 /* If TLS is available on this connection attempt to
754 start up a TLS session, unless the host is in hosts_avoid_tls. If successful,
755 send another EHLO - the server may give a different answer in secure mode. We
756 use a separate buffer for reading the response to STARTTLS so that if it is
757 negative, the original EHLO data is available for subsequent analysis, should
758 the client not be required to use TLS. If the response is bad, copy the buffer
759 for error analysis. */
763 && verify_check_given_host(&ob->hosts_avoid_tls, host) != OK
764 && verify_check_given_host(&ob->hosts_verify_avoid_tls, host) != OK
767 uschar buffer2[4096];
769 && !(done= smtp_write_command(&outblock, FALSE, "STARTTLS\r\n") >= 0))
772 /* If there is an I/O error, transmission of this message is deferred. If
773 there is a temporary rejection of STARRTLS and tls_tempfail_tryclear is
774 false, we also defer. However, if there is a temporary rejection of STARTTLS
775 and tls_tempfail_tryclear is true, or if there is an outright rejection of
776 STARTTLS, we carry on. This means we will try to send the message in clear,
777 unless the host is in hosts_require_tls (tested below). */
779 if (!smtps && !smtp_read_response(&inblock, buffer2, sizeof(buffer2), '2',
780 ob->command_timeout))
782 if (errno != 0 || buffer2[0] == 0 ||
783 (buffer2[0] == '4' && !ob->tls_tempfail_tryclear))
785 Ustrncpy(responsebuffer, buffer2, sizeof(responsebuffer));
787 goto RESPONSE_FAILED;
791 /* STARTTLS accepted or ssl-on-connect: try to negotiate a TLS session. */
794 int oldtimeout = ob->command_timeout;
798 ob->command_timeout = callout;
799 rc = tls_client_start(inblock.sock, host, addr, addr->transport
800 # ifdef EXPERIMENTAL_DANE
801 , dane ? &tlsa_dnsa : NULL
804 ob->command_timeout = oldtimeout;
806 /* TLS negotiation failed; give an error. Try in clear on a new
807 connection, if the options permit it for this host. */
812 (void)close(inblock.sock);
813 # ifdef EXPERIMENTAL_EVENT
814 (void) event_raise(addr->transport->event_action,
815 US"tcp:close", NULL);
817 # ifdef EXPERIMENTAL_DANE
822 log_write(0, LOG_MAIN, "DANE attempt failed;"
823 " trying CA-root TLS to %s [%s] (not in hosts_require_dane)",
824 host->name, host->address);
831 if ( ob->tls_tempfail_tryclear
833 && verify_check_given_host(&ob->hosts_require_tls, host) != OK
836 log_write(0, LOG_MAIN, "TLS session failure:"
837 " delivering unencrypted to %s [%s] (not in hosts_require_tls)",
838 host->name, host->address);
840 goto tls_retry_connection;
844 /*save_errno = ERRNO_TLSFAILURE;*/
845 /*message = US"failure while setting up TLS session";*/
851 /* TLS session is set up. Copy info for logging. */
852 addr->cipher = tls_out.cipher;
853 addr->peerdn = tls_out.peerdn;
855 /* For SMTPS we need to wait for the initial OK response, then do HELO. */
857 goto smtps_redo_greeting;
859 /* For STARTTLS we need to redo EHLO */
864 /* If the host is required to use a secure channel, ensure that we have one. */
865 if (tls_out.active < 0)
867 # ifdef EXPERIMENTAL_DANE
870 verify_check_given_host(&ob->hosts_require_tls, host) == OK
873 /*save_errno = ERRNO_TLSREQUIRED;*/
874 log_write(0, LOG_MAIN,
875 "H=%s [%s]: a TLS session is required for this host, but %s",
876 host->name, host->address,
877 tls_offered ? "an attempt to start TLS failed"
878 : "the server did not offer TLS support");
883 #endif /*SUPPORT_TLS*/
885 done = TRUE; /* so far so good; have response to HELO */
887 /*XXX the EHLO response would be analyzed here for IGNOREQUOTA, SIZE, PIPELINING */
889 /* For now, transport_filter by cutthrough-delivery is not supported */
890 /* Need proper integration with the proper transport mechanism. */
891 if (cutthrough.delivery)
893 if (addr->transport->filter_command)
895 cutthrough.delivery = FALSE;
896 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of transport filter\n");
901 cutthrough.delivery = FALSE;
902 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of DKIM signing\n");
911 /* Clear down of the TLS, SMTP and TCP layers on error is handled below. */
913 /* Failure to accept HELO is cached; this blocks the whole domain for all
914 senders. I/O errors and defer responses are not cached. */
918 *failure_ptr = US"mail"; /* At or before MAIL */
919 if (errno == 0 && responsebuffer[0] == '5')
921 setflag(addr, af_verify_nsfail);
922 new_domain_record.result = ccache_reject;
926 /* If we haven't authenticated, but are required to, give up. */
929 else done = smtp_auth(responsebuffer, sizeof(responsebuffer),
930 addr, host, ob, esmtp, &inblock, &outblock) == OK &&
932 /* Copy AUTH info for logging */
933 ( (addr->authenticator = client_authenticator),
934 (addr->auth_id = client_authenticated_id),
936 /* Build a mail-AUTH string (re-using responsebuffer for convenience */
937 !smtp_mail_auth_str(responsebuffer, sizeof(responsebuffer), addr, ob)
940 ( (addr->auth_sndr = client_authenticated_sender),
942 /* Send the MAIL command */
943 (smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>%s\r\n",
944 from_address, responsebuffer) >= 0)
947 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
950 deliver_host = deliver_host_address = NULL;
951 deliver_domain = save_deliver_domain;
953 /* If the host does not accept MAIL FROM:<>, arrange to cache this
954 information, but again, don't record anything for an I/O error or a defer. Do
955 not cache rejections of MAIL when a non-empty sender has been used, because
956 that blocks the whole domain for all senders. */
960 *failure_ptr = US"mail"; /* At or before MAIL */
961 if (errno == 0 && responsebuffer[0] == '5')
963 setflag(addr, af_verify_nsfail);
964 if (from_address[0] == 0)
965 new_domain_record.result = ccache_reject_mfnull;
969 /* Otherwise, proceed to check a "random" address (if required), then the
970 given address, and the postmaster address (if required). Between each check,
971 issue RSET, because some servers accept only one recipient after MAIL
974 Before doing this, set the result in the domain cache record to "accept",
975 unless its previous value was ccache_reject_mfnull. In that case, the domain
976 rejects MAIL FROM:<> and we want to continue to remember that. When that is
977 the case, we have got here only in the case of a recipient verification with
978 a non-null sender. */
982 new_domain_record.result =
983 (old_domain_cache_result == ccache_reject_mfnull)?
984 ccache_reject_mfnull: ccache_accept;
986 /* Do the random local part check first */
988 if (random_local_part != NULL)
990 uschar randombuffer[1024];
992 smtp_write_command(&outblock, FALSE,
993 "RCPT TO:<%.1000s@%.1000s>\r\n", random_local_part,
994 addr->domain) >= 0 &&
995 smtp_read_response(&inblock, randombuffer,
996 sizeof(randombuffer), '2', callout);
998 /* Remember when we last did a random test */
1000 new_domain_record.random_stamp = time(NULL);
1002 /* If accepted, we aren't going to do any further tests below. */
1005 new_domain_record.random_result = ccache_accept;
1007 /* Otherwise, cache a real negative response, and get back to the right
1008 state to send RCPT. Unless there's some problem such as a dropped
1009 connection, we expect to succeed, because the commands succeeded above.
1010 However, some servers drop the connection after responding to an
1011 invalid recipient, so on (any) error we drop and remake the connection.
1014 else if (errno == 0)
1016 /* This would be ok for 1st rcpt a cutthrough, but no way to
1017 handle a subsequent. So refuse to support any */
1018 cancel_cutthrough_connection("random-recipient");
1020 if (randombuffer[0] == '5')
1021 new_domain_record.random_result = ccache_reject;
1024 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
1025 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
1028 smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>\r\n",
1029 from_address) >= 0 &&
1030 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
1036 debug_printf("problem after random/rset/mfrom; reopen conn\n");
1037 random_local_part = NULL;
1039 tls_close(FALSE, TRUE);
1041 (void)close(inblock.sock);
1042 #ifdef EXPERIMENTAL_EVENT
1043 (void) event_raise(addr->transport->event_action,
1044 US"tcp:close", NULL);
1046 goto tls_retry_connection;
1049 else done = FALSE; /* Some timeout/connection problem */
1050 } /* Random check */
1052 /* If the host is accepting all local parts, as determined by the "random"
1053 check, we don't need to waste time doing any further checking. */
1055 if (new_domain_record.random_result != ccache_accept && done)
1057 /* Get the rcpt_include_affixes flag from the transport if there is one,
1058 but assume FALSE if there is not. */
1061 smtp_write_command(&outblock, FALSE, "RCPT TO:<%.1000s>\r\n",
1062 transport_rcpt_address(addr,
1063 (addr->transport == NULL)? FALSE :
1064 addr->transport->rcpt_include_affixes)) >= 0 &&
1065 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
1069 new_address_record.result = ccache_accept;
1070 else if (errno == 0 && responsebuffer[0] == '5')
1072 *failure_ptr = US"recipient";
1073 new_address_record.result = ccache_reject;
1076 /* Do postmaster check if requested; if a full check is required, we
1077 check for RCPT TO:<postmaster> (no domain) in accordance with RFC 821. */
1079 if (done && pm_mailfrom != NULL)
1081 /* Could possibly shift before main verify, just above, and be ok
1082 for cutthrough. But no way to handle a subsequent rcpt, so just
1084 cancel_cutthrough_connection("postmaster verify");
1085 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of postmaster verify\n");
1088 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
1089 smtp_read_response(&inblock, responsebuffer,
1090 sizeof(responsebuffer), '2', callout) &&
1092 smtp_write_command(&outblock, FALSE,
1093 "MAIL FROM:<%s>\r\n", pm_mailfrom) >= 0 &&
1094 smtp_read_response(&inblock, responsebuffer,
1095 sizeof(responsebuffer), '2', callout) &&
1097 /* First try using the current domain */
1100 smtp_write_command(&outblock, FALSE,
1101 "RCPT TO:<postmaster@%.1000s>\r\n", addr->domain) >= 0 &&
1102 smtp_read_response(&inblock, responsebuffer,
1103 sizeof(responsebuffer), '2', callout)
1108 /* If that doesn't work, and a full check is requested,
1109 try without the domain. */
1112 (options & vopt_callout_fullpm) != 0 &&
1113 smtp_write_command(&outblock, FALSE,
1114 "RCPT TO:<postmaster>\r\n") >= 0 &&
1115 smtp_read_response(&inblock, responsebuffer,
1116 sizeof(responsebuffer), '2', callout)
1119 /* Sort out the cache record */
1121 new_domain_record.postmaster_stamp = time(NULL);
1124 new_domain_record.postmaster_result = ccache_accept;
1125 else if (errno == 0 && responsebuffer[0] == '5')
1127 *failure_ptr = US"postmaster";
1128 setflag(addr, af_verify_pmfail);
1129 new_domain_record.postmaster_result = ccache_reject;
1132 } /* Random not accepted */
1133 } /* MAIL FROM: accepted */
1135 /* For any failure of the main check, other than a negative response, we just
1136 close the connection and carry on. We can identify a negative response by the
1137 fact that errno is zero. For I/O errors it will be non-zero
1139 Set up different error texts for logging and for sending back to the caller
1140 as an SMTP response. Log in all cases, using a one-line format. For sender
1141 callouts, give a full response to the caller, but for recipient callouts,
1142 don't give the IP address because this may be an internal host whose identity
1143 is not to be widely broadcast. */
1147 if (errno == ETIMEDOUT)
1149 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
1152 else if (errno == 0)
1154 if (*responsebuffer == 0) Ustrcpy(responsebuffer, US"connection dropped");
1157 string_sprintf("response to \"%s\" from %s [%s] was: %s",
1158 big_buffer, host->name, host->address,
1159 string_printing(responsebuffer));
1161 addr->user_message = is_recipient?
1162 string_sprintf("Callout verification failed:\n%s", responsebuffer)
1164 string_sprintf("Called: %s\nSent: %s\nResponse: %s",
1165 host->address, big_buffer, responsebuffer);
1167 /* Hard rejection ends the process */
1169 if (responsebuffer[0] == '5') /* Address rejected */
1177 /* End the SMTP conversation and close the connection. */
1179 /* Cutthrough - on a successfull connect and recipient-verify with
1180 use-sender and we are 1st rcpt and have no cutthrough conn so far
1181 here is where we want to leave the conn open */
1182 if ( cutthrough.delivery
1186 && (options & (vopt_callout_recipsender|vopt_callout_recippmaster)) == vopt_callout_recipsender
1187 && !random_local_part
1189 && cutthrough.fd < 0
1193 cutthrough.fd = outblock.sock; /* We assume no buffer in use in the outblock */
1194 cutthrough.nrcpt = 1;
1195 cutthrough.interface = interface;
1196 cutthrough.host = *host;
1197 cutthrough.addr = *addr; /* Save the address_item for later logging */
1198 cutthrough.addr.next = NULL;
1199 cutthrough.addr.host_used = &cutthrough.host;
1201 *(cutthrough.addr.parent = store_get(sizeof(address_item))) =
1203 ctblock.buffer = ctbuffer;
1204 ctblock.buffersize = sizeof(ctbuffer);
1205 ctblock.ptr = ctbuffer;
1206 /* ctblock.cmd_count = 0; ctblock.authenticating = FALSE; */
1207 ctblock.sock = cutthrough.fd;
1211 /* Ensure no cutthrough on multiple address verifies */
1212 if (options & vopt_callout_recipsender)
1213 cancel_cutthrough_connection("multiple verify calls");
1214 if (send_quit) (void)smtp_write_command(&outblock, FALSE, "QUIT\r\n");
1217 tls_close(FALSE, TRUE);
1219 (void)close(inblock.sock);
1220 #ifdef EXPERIMENTAL_EVENT
1221 (void) event_raise(addr->transport->event_action,
1222 US"tcp:close", NULL);
1226 } /* Loop through all hosts, while !done */
1229 /* If we get here with done == TRUE, a successful callout happened, and yield
1230 will be set OK or FAIL according to the response to the RCPT command.
1231 Otherwise, we looped through the hosts but couldn't complete the business.
1232 However, there may be domain-specific information to cache in both cases.
1234 The value of the result field in the new_domain record is ccache_unknown if
1235 there was an error before or with MAIL FROM:, and errno was not zero,
1236 implying some kind of I/O error. We don't want to write the cache in that case.
1237 Otherwise the value is ccache_accept, ccache_reject, or ccache_reject_mfnull. */
1239 if (!callout_no_cache && new_domain_record.result != ccache_unknown)
1241 if ((dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE))
1244 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
1248 (void)dbfn_write(dbm_file, addr->domain, &new_domain_record,
1249 (int)sizeof(dbdata_callout_cache));
1250 HDEBUG(D_verify) debug_printf("wrote callout cache domain record:\n"
1251 " result=%d postmaster=%d random=%d\n",
1252 new_domain_record.result,
1253 new_domain_record.postmaster_result,
1254 new_domain_record.random_result);
1258 /* If a definite result was obtained for the callout, cache it unless caching
1263 if (!callout_no_cache && new_address_record.result != ccache_unknown)
1265 if (dbm_file == NULL)
1266 dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE);
1267 if (dbm_file == NULL)
1269 HDEBUG(D_verify) debug_printf("no callout cache available\n");
1273 (void)dbfn_write(dbm_file, address_key, &new_address_record,
1274 (int)sizeof(dbdata_callout_cache_address));
1275 HDEBUG(D_verify) debug_printf("wrote %s callout cache address record\n",
1276 (new_address_record.result == ccache_accept)? "positive" : "negative");
1281 /* Failure to connect to any host, or any response other than 2xx or 5xx is a
1282 temporary error. If there was only one host, and a response was received, leave
1283 it alone if supplying details. Otherwise, give a generic response. */
1287 uschar *dullmsg = string_sprintf("Could not complete %s verify callout",
1288 is_recipient? "recipient" : "sender");
1291 if (host_list->next != NULL || addr->message == NULL) addr->message = dullmsg;
1293 addr->user_message = (!smtp_return_error_details)? dullmsg :
1294 string_sprintf("%s for <%s>.\n"
1295 "The mail server(s) for the domain may be temporarily unreachable, or\n"
1296 "they may be permanently unreachable from this server. In the latter case,\n%s",
1297 dullmsg, addr->address,
1299 "the address will never be accepted."
1301 "you need to change the address or create an MX record for its domain\n"
1302 "if it is supposed to be generally accessible from the Internet.\n"
1303 "Talk to your mail administrator for details.");
1305 /* Force a specific error code */
1307 addr->basic_errno = ERRNO_CALLOUTDEFER;
1310 /* Come here from within the cache-reading code on fast-track exit. */
1313 if (dbm_file != NULL) dbfn_close(dbm_file);
1319 /* Called after recipient-acl to get a cutthrough connection open when
1320 one was requested and a recipient-verify wasn't subsequently done.
1323 open_cutthrough_connection( address_item * addr )
1327 /* Use a recipient-verify-callout to set up the cutthrough connection. */
1328 /* We must use a copy of the address for verification, because it might
1332 HDEBUG(D_acl) debug_printf("----------- %s cutthrough setup ------------\n",
1333 rcpt_count > 1 ? "more" : "start");
1334 (void) verify_address(&addr2, NULL,
1335 vopt_is_recipient | vopt_callout_recipsender | vopt_callout_no_cache,
1336 CUTTHROUGH_CMD_TIMEOUT, -1, -1,
1338 HDEBUG(D_acl) debug_printf("----------- end cutthrough setup ------------\n");
1344 /* Send given number of bytes from the buffer */
1346 cutthrough_send(int n)
1348 if(cutthrough.fd < 0)
1353 (tls_out.active == cutthrough.fd) ? tls_write(FALSE, ctblock.buffer, n) :
1355 send(cutthrough.fd, ctblock.buffer, n, 0) > 0
1358 transport_count += n;
1359 ctblock.ptr= ctblock.buffer;
1363 HDEBUG(D_transport|D_acl) debug_printf("cutthrough_send failed: %s\n", strerror(errno));
1370 _cutthrough_puts(uschar * cp, int n)
1374 if(ctblock.ptr >= ctblock.buffer+ctblock.buffersize)
1375 if(!cutthrough_send(ctblock.buffersize))
1378 *ctblock.ptr++ = *cp++;
1383 /* Buffered output of counted data block. Return boolean success */
1385 cutthrough_puts(uschar * cp, int n)
1387 if (cutthrough.fd < 0) return TRUE;
1388 if (_cutthrough_puts(cp, n)) return TRUE;
1389 cancel_cutthrough_connection("transmit failed");
1395 _cutthrough_flush_send(void)
1397 int n= ctblock.ptr-ctblock.buffer;
1400 if(!cutthrough_send(n))
1406 /* Send out any bufferred output. Return boolean success. */
1408 cutthrough_flush_send(void)
1410 if (_cutthrough_flush_send()) return TRUE;
1411 cancel_cutthrough_connection("transmit failed");
1417 cutthrough_put_nl(void)
1419 return cutthrough_puts(US"\r\n", 2);
1423 /* Get and check response from cutthrough target */
1425 cutthrough_response(char expect, uschar ** copy)
1427 smtp_inblock inblock;
1428 uschar inbuffer[4096];
1429 uschar responsebuffer[4096];
1431 inblock.buffer = inbuffer;
1432 inblock.buffersize = sizeof(inbuffer);
1433 inblock.ptr = inbuffer;
1434 inblock.ptrend = inbuffer;
1435 inblock.sock = cutthrough.fd;
1436 /* this relies on (inblock.sock == tls_out.active) */
1437 if(!smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), expect, CUTTHROUGH_DATA_TIMEOUT))
1438 cancel_cutthrough_connection("target timeout on read");
1443 *copy = cp = string_copy(responsebuffer);
1444 /* Trim the trailing end of line */
1445 cp += Ustrlen(responsebuffer);
1446 if(cp > *copy && cp[-1] == '\n') *--cp = '\0';
1447 if(cp > *copy && cp[-1] == '\r') *--cp = '\0';
1450 return responsebuffer[0];
1454 /* Negotiate dataphase with the cutthrough target, returning success boolean */
1456 cutthrough_predata(void)
1458 if(cutthrough.fd < 0)
1461 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> DATA\n");
1462 cutthrough_puts(US"DATA\r\n", 6);
1463 cutthrough_flush_send();
1465 /* Assume nothing buffered. If it was it gets ignored. */
1466 return cutthrough_response('3', NULL) == '3';
1470 /* fd and use_crlf args only to match write_chunk() */
1472 cutthrough_write_chunk(int fd, uschar * s, int len, BOOL use_crlf)
1475 while(s && (s2 = Ustrchr(s, '\n')))
1477 if(!cutthrough_puts(s, s2-s) || !cutthrough_put_nl())
1485 /* Buffered send of headers. Return success boolean. */
1486 /* Expands newlines to wire format (CR,NL). */
1487 /* Also sends header-terminating blank line. */
1489 cutthrough_headers_send(void)
1491 if(cutthrough.fd < 0)
1494 /* We share a routine with the mainline transport to handle header add/remove/rewrites,
1495 but having a separate buffered-output function (for now)
1497 HDEBUG(D_acl) debug_printf("----------- start cutthrough headers send -----------\n");
1499 if (!transport_headers_send(&cutthrough.addr, cutthrough.fd,
1500 cutthrough.addr.transport->add_headers,
1501 cutthrough.addr.transport->remove_headers,
1502 &cutthrough_write_chunk, TRUE,
1503 cutthrough.addr.transport->rewrite_rules,
1504 cutthrough.addr.transport->rewrite_existflags))
1507 HDEBUG(D_acl) debug_printf("----------- done cutthrough headers send ------------\n");
1513 close_cutthrough_connection(const char * why)
1515 if(cutthrough.fd >= 0)
1517 /* We could be sending this after a bunch of data, but that is ok as
1518 the only way to cancel the transfer in dataphase is to drop the tcp
1519 conn before the final dot.
1521 ctblock.ptr = ctbuffer;
1522 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> QUIT\n");
1523 _cutthrough_puts(US"QUIT\r\n", 6); /* avoid recursion */
1524 _cutthrough_flush_send();
1525 /* No wait for response */
1528 tls_close(FALSE, TRUE);
1530 (void)close(cutthrough.fd);
1532 HDEBUG(D_acl) debug_printf("----------- cutthrough shutdown (%s) ------------\n", why);
1534 ctblock.ptr = ctbuffer;
1538 cancel_cutthrough_connection(const char * why)
1540 close_cutthrough_connection(why);
1541 cutthrough.delivery = FALSE;
1547 /* Have senders final-dot. Send one to cutthrough target, and grab the response.
1548 Log an OK response as a transmission.
1549 Close the connection.
1550 Return smtp response-class digit.
1553 cutthrough_finaldot(void)
1556 address_item * addr;
1557 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> .\n");
1559 /* Assume data finshed with new-line */
1560 if( !cutthrough_puts(US".", 1)
1561 || !cutthrough_put_nl()
1562 || !cutthrough_flush_send()
1564 return cutthrough.addr.message;
1566 res = cutthrough_response('2', &cutthrough.addr.message);
1567 for (addr = &cutthrough.addr; addr; addr = addr->next)
1569 addr->message = cutthrough.addr.message;
1573 delivery_log(LOG_MAIN, addr, (int)'>', NULL);
1574 close_cutthrough_connection("delivered");
1578 delivery_log(LOG_MAIN, addr, 0,
1579 US"tmp-reject from cutthrough after DATA:");
1583 delivery_log(LOG_MAIN|LOG_REJECT, addr, 0,
1584 US"rejected after DATA:");
1591 return cutthrough.addr.message;
1596 /*************************************************
1597 * Copy error to toplevel address *
1598 *************************************************/
1600 /* This function is used when a verify fails or defers, to ensure that the
1601 failure or defer information is in the original toplevel address. This applies
1602 when an address is redirected to a single new address, and the failure or
1603 deferral happens to the child address.
1606 vaddr the verify address item
1607 addr the final address item
1610 Returns: the value of YIELD
1614 copy_error(address_item *vaddr, address_item *addr, int yield)
1618 vaddr->message = addr->message;
1619 vaddr->user_message = addr->user_message;
1620 vaddr->basic_errno = addr->basic_errno;
1621 vaddr->more_errno = addr->more_errno;
1622 vaddr->p.address_data = addr->p.address_data;
1623 copyflag(vaddr, addr, af_pass_message);
1631 /**************************************************
1632 * printf that automatically handles TLS if needed *
1633 ***************************************************/
1635 /* This function is used by verify_address() as a substitute for all fprintf()
1636 calls; a direct fprintf() will not produce output in a TLS SMTP session, such
1637 as a response to an EXPN command. smtp_in.c makes smtp_printf available but
1638 that assumes that we always use the smtp_out FILE* when not using TLS or the
1639 ssl buffer when we are. Instead we take a FILE* parameter and check to see if
1640 that is smtp_out; if so, smtp_printf() with TLS support, otherwise regular
1644 f the candidate FILE* to write to
1645 format format string
1646 ... optional arguments
1652 static void PRINTF_FUNCTION(2,3)
1653 respond_printf(FILE *f, const char *format, ...)
1657 va_start(ap, format);
1658 if (smtp_out && (f == smtp_out))
1659 smtp_vprintf(format, ap);
1661 vfprintf(f, format, ap);
1667 /*************************************************
1668 * Verify an email address *
1669 *************************************************/
1671 /* This function is used both for verification (-bv and at other times) and
1672 address testing (-bt), which is indicated by address_test_mode being set.
1675 vaddr contains the address to verify; the next field in this block
1677 f if not NULL, write the result to this file
1678 options various option bits:
1679 vopt_fake_sender => this sender verify is not for the real
1680 sender (it was verify=sender=xxxx or an address from a
1681 header line) - rewriting must not change sender_address
1682 vopt_is_recipient => this is a recipient address, otherwise
1683 it's a sender address - this affects qualification and
1684 rewriting and messages from callouts
1685 vopt_qualify => qualify an unqualified address; else error
1686 vopt_expn => called from SMTP EXPN command
1687 vopt_success_on_redirect => when a new address is generated
1688 the verification instantly succeeds
1690 These ones are used by do_callout() -- the options variable
1693 vopt_callout_fullpm => if postmaster check, do full one
1694 vopt_callout_no_cache => don't use callout cache
1695 vopt_callout_random => do the "random" thing
1696 vopt_callout_recipsender => use real sender for recipient
1697 vopt_callout_recippmaster => use postmaster for recipient
1699 callout if > 0, specifies that callout is required, and gives timeout
1700 for individual commands
1701 callout_overall if > 0, gives overall timeout for the callout function;
1702 if < 0, a default is used (see do_callout())
1703 callout_connect the connection timeout for callouts
1704 se_mailfrom when callout is requested to verify a sender, use this
1705 in MAIL FROM; NULL => ""
1706 pm_mailfrom when callout is requested, if non-NULL, do the postmaster
1707 thing and use this as the sender address (may be "")
1709 routed if not NULL, set TRUE if routing succeeded, so we can
1710 distinguish between routing failed and callout failed
1712 Returns: OK address verified
1713 FAIL address failed to verify
1714 DEFER can't tell at present
1718 verify_address(address_item *vaddr, FILE *f, int options, int callout,
1719 int callout_overall, int callout_connect, uschar *se_mailfrom,
1720 uschar *pm_mailfrom, BOOL *routed)
1723 BOOL full_info = (f == NULL)? FALSE : (debug_selector != 0);
1724 BOOL is_recipient = (options & vopt_is_recipient) != 0;
1725 BOOL expn = (options & vopt_expn) != 0;
1726 BOOL success_on_redirect = (options & vopt_success_on_redirect) != 0;
1729 int verify_type = expn? v_expn :
1730 address_test_mode? v_none :
1731 is_recipient? v_recipient : v_sender;
1732 address_item *addr_list;
1733 address_item *addr_new = NULL;
1734 address_item *addr_remote = NULL;
1735 address_item *addr_local = NULL;
1736 address_item *addr_succeed = NULL;
1737 uschar **failure_ptr = is_recipient?
1738 &recipient_verify_failure : &sender_verify_failure;
1739 uschar *ko_prefix, *cr;
1740 uschar *address = vaddr->address;
1741 uschar *save_sender;
1742 uschar null_sender[] = { 0 }; /* Ensure writeable memory */
1744 /* Clear, just in case */
1746 *failure_ptr = NULL;
1748 /* Set up a prefix and suffix for error message which allow us to use the same
1749 output statements both in EXPN mode (where an SMTP response is needed) and when
1750 debugging with an output file. */
1754 ko_prefix = US"553 ";
1757 else ko_prefix = cr = US"";
1759 /* Add qualify domain if permitted; otherwise an unqualified address fails. */
1761 if (parse_find_at(address) == NULL)
1763 if ((options & vopt_qualify) == 0)
1766 respond_printf(f, "%sA domain is required for \"%s\"%s\n",
1767 ko_prefix, address, cr);
1768 *failure_ptr = US"qualify";
1771 address = rewrite_address_qualify(address, is_recipient);
1776 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1777 debug_printf("%s %s\n", address_test_mode? "Testing" : "Verifying", address);
1780 /* Rewrite and report on it. Clear the domain and local part caches - these
1781 may have been set by domains and local part tests during an ACL. */
1783 if (global_rewrite_rules != NULL)
1785 uschar *old = address;
1786 address = rewrite_address(address, is_recipient, FALSE,
1787 global_rewrite_rules, rewrite_existflags);
1790 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->localpart_cache[i] = 0;
1791 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->domain_cache[i] = 0;
1792 if (f != NULL && !expn) fprintf(f, "Address rewritten as: %s\n", address);
1796 /* If this is the real sender address, we must update sender_address at
1797 this point, because it may be referred to in the routers. */
1799 if ((options & (vopt_fake_sender|vopt_is_recipient)) == 0)
1800 sender_address = address;
1802 /* If the address was rewritten to <> no verification can be done, and we have
1803 to return OK. This rewriting is permitted only for sender addresses; for other
1804 addresses, such rewriting fails. */
1806 if (address[0] == 0) return OK;
1808 /* Flip the legacy TLS-related variables over to the outbound set in case
1809 they're used in the context of a transport used by verification. Reset them
1810 at exit from this routine. */
1812 tls_modify_variables(&tls_out);
1814 /* Save a copy of the sender address for re-instating if we change it to <>
1815 while verifying a sender address (a nice bit of self-reference there). */
1817 save_sender = sender_address;
1819 /* Update the address structure with the possibly qualified and rewritten
1820 address. Set it up as the starting address on the chain of new addresses. */
1822 vaddr->address = address;
1825 /* We need a loop, because an address can generate new addresses. We must also
1826 cope with generated pipes and files at the top level. (See also the code and
1827 comment in deliver.c.) However, it is usually the case that the router for
1828 user's .forward files has its verify flag turned off.
1830 If an address generates more than one child, the loop is used only when
1831 full_info is set, and this can only be set locally. Remote enquiries just get
1832 information about the top level address, not anything that it generated. */
1834 while (addr_new != NULL)
1837 address_item *addr = addr_new;
1839 addr_new = addr->next;
1844 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1845 debug_printf("Considering %s\n", addr->address);
1848 /* Handle generated pipe, file or reply addresses. We don't get these
1849 when handling EXPN, as it does only one level of expansion. */
1851 if (testflag(addr, af_pfr))
1858 if (addr->address[0] == '>')
1860 allow = testflag(addr, af_allow_reply);
1861 fprintf(f, "%s -> mail %s", addr->parent->address, addr->address + 1);
1865 allow = (addr->address[0] == '|')?
1866 testflag(addr, af_allow_pipe) : testflag(addr, af_allow_file);
1867 fprintf(f, "%s -> %s", addr->parent->address, addr->address);
1870 if (addr->basic_errno == ERRNO_BADTRANSPORT)
1871 fprintf(f, "\n*** Error in setting up pipe, file, or autoreply:\n"
1872 "%s\n", addr->message);
1874 fprintf(f, "\n transport = %s\n", addr->transport->name);
1876 fprintf(f, " *** forbidden ***\n");
1881 /* Just in case some router parameter refers to it. */
1883 return_path = (addr->p.errors_address != NULL)?
1884 addr->p.errors_address : sender_address;
1886 /* Split the address into domain and local part, handling the %-hack if
1887 necessary, and then route it. While routing a sender address, set
1888 $sender_address to <> because that is what it will be if we were trying to
1889 send a bounce to the sender. */
1891 if (routed != NULL) *routed = FALSE;
1892 if ((rc = deliver_split_address(addr)) == OK)
1894 if (!is_recipient) sender_address = null_sender;
1895 rc = route_address(addr, &addr_local, &addr_remote, &addr_new,
1896 &addr_succeed, verify_type);
1897 sender_address = save_sender; /* Put back the real sender */
1900 /* If routing an address succeeded, set the flag that remembers, for use when
1901 an ACL cached a sender verify (in case a callout fails). Then if routing set
1902 up a list of hosts or the transport has a host list, and the callout option
1903 is set, and we aren't in a host checking run, do the callout verification,
1904 and set another flag that notes that a callout happened. */
1908 if (routed != NULL) *routed = TRUE;
1911 host_item *host_list = addr->host_list;
1913 /* Make up some data for use in the case where there is no remote
1916 transport_feedback tf = {
1917 NULL, /* interface (=> any) */
1918 US"smtp", /* port */
1919 US"smtp", /* protocol */
1921 US"$smtp_active_hostname", /* helo_data */
1922 FALSE, /* hosts_override */
1923 FALSE, /* hosts_randomize */
1924 FALSE, /* gethostbyname */
1925 TRUE, /* qualify_single */
1926 FALSE /* search_parents */
1929 /* If verification yielded a remote transport, we want to use that
1930 transport's options, so as to mimic what would happen if we were really
1931 sending a message to this address. */
1933 if (addr->transport != NULL && !addr->transport->info->local)
1935 (void)(addr->transport->setup)(addr->transport, addr, &tf, 0, 0, NULL);
1937 /* If the transport has hosts and the router does not, or if the
1938 transport is configured to override the router's hosts, we must build a
1939 host list of the transport's hosts, and find the IP addresses */
1941 if (tf.hosts != NULL && (host_list == NULL || tf.hosts_override))
1944 const uschar *save_deliver_domain = deliver_domain;
1945 uschar *save_deliver_localpart = deliver_localpart;
1947 host_list = NULL; /* Ignore the router's hosts */
1949 deliver_domain = addr->domain;
1950 deliver_localpart = addr->local_part;
1951 s = expand_string(tf.hosts);
1952 deliver_domain = save_deliver_domain;
1953 deliver_localpart = save_deliver_localpart;
1957 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand list of hosts "
1958 "\"%s\" in %s transport for callout: %s", tf.hosts,
1959 addr->transport->name, expand_string_message);
1964 host_item *host, *nexthost;
1965 host_build_hostlist(&host_list, s, tf.hosts_randomize);
1967 /* Just ignore failures to find a host address. If we don't manage
1968 to find any addresses, the callout will defer. Note that more than
1969 one address may be found for a single host, which will result in
1970 additional host items being inserted into the chain. Hence we must
1971 save the next host first. */
1973 flags = HOST_FIND_BY_A;
1974 if (tf.qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
1975 if (tf.search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
1977 for (host = host_list; host != NULL; host = nexthost)
1979 nexthost = host->next;
1980 if (tf.gethostbyname ||
1981 string_is_ip_address(host->name, NULL) != 0)
1982 (void)host_find_byname(host, NULL, flags, NULL, TRUE);
1985 uschar * d_request = NULL, * d_require = NULL;
1986 if (Ustrcmp(addr->transport->driver_name, "smtp") == 0)
1988 smtp_transport_options_block * ob =
1989 (smtp_transport_options_block *)
1990 addr->transport->options_block;
1991 d_request = ob->dnssec_request_domains;
1992 d_require = ob->dnssec_require_domains;
1995 (void)host_find_bydns(host, NULL, flags, NULL, NULL, NULL,
1996 d_request, d_require, NULL, NULL);
2003 /* Can only do a callout if we have at least one host! If the callout
2004 fails, it will have set ${sender,recipient}_verify_failure. */
2006 if (host_list != NULL)
2008 HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n");
2009 if (host_checking && !host_checking_callout)
2012 debug_printf("... callout omitted by default when host testing\n"
2013 "(Use -bhc if you want the callouts to happen.)\n");
2018 deliver_set_expansions(addr);
2020 verify_mode = is_recipient ? US"R" : US"S";
2021 rc = do_callout(addr, host_list, &tf, callout, callout_overall,
2022 callout_connect, options, se_mailfrom, pm_mailfrom);
2028 HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor "
2029 "transport provided a host list\n");
2034 /* Otherwise, any failure is a routing failure */
2036 else *failure_ptr = US"route";
2038 /* A router may return REROUTED if it has set up a child address as a result
2039 of a change of domain name (typically from widening). In this case we always
2040 want to continue to verify the new child. */
2042 if (rc == REROUTED) continue;
2044 /* Handle hard failures */
2051 address_item *p = addr->parent;
2053 respond_printf(f, "%s%s %s", ko_prefix,
2054 full_info? addr->address : address,
2055 address_test_mode? "is undeliverable" : "failed to verify");
2056 if (!expn && admin_user)
2058 if (addr->basic_errno > 0)
2059 respond_printf(f, ": %s", strerror(addr->basic_errno));
2060 if (addr->message != NULL)
2061 respond_printf(f, ": %s", addr->message);
2064 /* Show parents iff doing full info */
2066 if (full_info) while (p != NULL)
2068 respond_printf(f, "%s\n <-- %s", cr, p->address);
2071 respond_printf(f, "%s\n", cr);
2073 cancel_cutthrough_connection("routing hard fail");
2077 yield = copy_error(vaddr, addr, FAIL);
2085 else if (rc == DEFER)
2090 address_item *p = addr->parent;
2091 respond_printf(f, "%s%s cannot be resolved at this time", ko_prefix,
2092 full_info? addr->address : address);
2093 if (!expn && admin_user)
2095 if (addr->basic_errno > 0)
2096 respond_printf(f, ": %s", strerror(addr->basic_errno));
2097 if (addr->message != NULL)
2098 respond_printf(f, ": %s", addr->message);
2099 else if (addr->basic_errno <= 0)
2100 respond_printf(f, ": unknown error");
2103 /* Show parents iff doing full info */
2105 if (full_info) while (p != NULL)
2107 respond_printf(f, "%s\n <-- %s", cr, p->address);
2110 respond_printf(f, "%s\n", cr);
2112 cancel_cutthrough_connection("routing soft fail");
2116 yield = copy_error(vaddr, addr, DEFER);
2119 else if (yield == OK) yield = DEFER;
2122 /* If we are handling EXPN, we do not want to continue to route beyond
2123 the top level (whose address is in "address"). */
2127 uschar *ok_prefix = US"250-";
2128 if (addr_new == NULL)
2130 if (addr_local == NULL && addr_remote == NULL)
2131 respond_printf(f, "250 mail to <%s> is discarded\r\n", address);
2133 respond_printf(f, "250 <%s>\r\n", address);
2135 else while (addr_new != NULL)
2137 address_item *addr2 = addr_new;
2138 addr_new = addr2->next;
2139 if (addr_new == NULL) ok_prefix = US"250 ";
2140 respond_printf(f, "%s<%s>\r\n", ok_prefix, addr2->address);
2146 /* Successful routing other than EXPN. */
2150 /* Handle successful routing when short info wanted. Otherwise continue for
2151 other (generated) addresses. Short info is the operational case. Full info
2152 can be requested only when debug_selector != 0 and a file is supplied.
2154 There is a conflict between the use of aliasing as an alternate email
2155 address, and as a sort of mailing list. If an alias turns the incoming
2156 address into just one address (e.g. J.Caesar->jc44) you may well want to
2157 carry on verifying the generated address to ensure it is valid when
2158 checking incoming mail. If aliasing generates multiple addresses, you
2159 probably don't want to do this. Exim therefore treats the generation of
2160 just a single new address as a special case, and continues on to verify the
2161 generated address. */
2163 if (!full_info && /* Stop if short info wanted AND */
2164 (((addr_new == NULL || /* No new address OR */
2165 addr_new->next != NULL || /* More than one new address OR */
2166 testflag(addr_new, af_pfr))) /* New address is pfr */
2168 (addr_new != NULL && /* At least one new address AND */
2169 success_on_redirect))) /* success_on_redirect is set */
2171 if (f != NULL) fprintf(f, "%s %s\n", address,
2172 address_test_mode? "is deliverable" : "verified");
2174 /* If we have carried on to verify a child address, we want the value
2175 of $address_data to be that of the child */
2177 vaddr->p.address_data = addr->p.address_data;
2182 } /* Loop for generated addresses */
2184 /* Display the full results of the successful routing, including any generated
2185 addresses. Control gets here only when full_info is set, which requires f not
2186 to be NULL, and this occurs only when a top-level verify is called with the
2187 debugging switch on.
2189 If there are no local and no remote addresses, and there were no pipes, files,
2190 or autoreplies, and there were no errors or deferments, the message is to be
2191 discarded, usually because of the use of :blackhole: in an alias file. */
2193 if (allok && addr_local == NULL && addr_remote == NULL)
2195 fprintf(f, "mail to %s is discarded\n", address);
2199 for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++)
2201 while (addr_list != NULL)
2203 address_item *addr = addr_list;
2204 address_item *p = addr->parent;
2205 addr_list = addr->next;
2207 fprintf(f, "%s", CS addr->address);
2208 #ifdef EXPERIMENTAL_SRS
2209 if(addr->p.srs_sender)
2210 fprintf(f, " [srs = %s]", addr->p.srs_sender);
2213 /* If the address is a duplicate, show something about it. */
2215 if (!testflag(addr, af_pfr))
2218 if ((tnode = tree_search(tree_duplicates, addr->unique)) != NULL)
2219 fprintf(f, " [duplicate, would not be delivered]");
2220 else tree_add_duplicate(addr->unique, addr);
2223 /* Now show its parents */
2227 fprintf(f, "\n <-- %s", p->address);
2232 /* Show router, and transport */
2234 fprintf(f, "router = %s, ", addr->router->name);
2235 fprintf(f, "transport = %s\n", (addr->transport == NULL)? US"unset" :
2236 addr->transport->name);
2238 /* Show any hosts that are set up by a router unless the transport
2239 is going to override them; fiddle a bit to get a nice format. */
2241 if (addr->host_list != NULL && addr->transport != NULL &&
2242 !addr->transport->overrides_hosts)
2247 for (h = addr->host_list; h != NULL; h = h->next)
2249 int len = Ustrlen(h->name);
2250 if (len > maxlen) maxlen = len;
2251 len = (h->address != NULL)? Ustrlen(h->address) : 7;
2252 if (len > maxaddlen) maxaddlen = len;
2254 for (h = addr->host_list; h != NULL; h = h->next)
2256 int len = Ustrlen(h->name);
2257 fprintf(f, " host %s ", h->name);
2258 while (len++ < maxlen) fprintf(f, " ");
2259 if (h->address != NULL)
2261 fprintf(f, "[%s] ", h->address);
2262 len = Ustrlen(h->address);
2264 else if (!addr->transport->info->local) /* Omit [unknown] for local */
2266 fprintf(f, "[unknown] ");
2270 while (len++ < maxaddlen) fprintf(f," ");
2271 if (h->mx >= 0) fprintf(f, "MX=%d", h->mx);
2272 if (h->port != PORT_NONE) fprintf(f, " port=%d", h->port);
2273 if (h->status == hstatus_unusable) fprintf(f, " ** unusable **");
2280 /* Yield will be DEFER or FAIL if any one address has, only for full_info (which is
2281 the -bv or -bt case). */
2284 tls_modify_variables(&tls_in);
2292 /*************************************************
2293 * Check headers for syntax errors *
2294 *************************************************/
2296 /* This function checks those header lines that contain addresses, and verifies
2297 that all the addresses therein are syntactially correct.
2300 msgptr where to put an error message
2307 verify_check_headers(uschar **msgptr)
2313 for (h = header_list; h != NULL && yield == OK; h = h->next)
2315 if (h->type != htype_from &&
2316 h->type != htype_reply_to &&
2317 h->type != htype_sender &&
2318 h->type != htype_to &&
2319 h->type != htype_cc &&
2320 h->type != htype_bcc)
2323 colon = Ustrchr(h->text, ':');
2325 while (isspace(*s)) s++;
2327 /* Loop for multiple addresses in the header, enabling group syntax. Note
2328 that we have to reset this after the header has been scanned. */
2330 parse_allow_group = TRUE;
2334 uschar *ss = parse_find_address_end(s, FALSE);
2335 uschar *recipient, *errmess;
2336 int terminator = *ss;
2337 int start, end, domain;
2339 /* Temporarily terminate the string at this point, and extract the
2340 operative address within, allowing group syntax. */
2343 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2346 /* Permit an unqualified address only if the message is local, or if the
2347 sending host is configured to be permitted to send them. */
2349 if (recipient != NULL && domain == 0)
2351 if (h->type == htype_from || h->type == htype_sender)
2353 if (!allow_unqualified_sender) recipient = NULL;
2357 if (!allow_unqualified_recipient) recipient = NULL;
2359 if (recipient == NULL) errmess = US"unqualified address not permitted";
2362 /* It's an error if no address could be extracted, except for the special
2363 case of an empty address. */
2365 if (recipient == NULL && Ustrcmp(errmess, "empty address") != 0)
2367 uschar *verb = US"is";
2372 /* Arrange not to include any white space at the end in the
2373 error message or the header name. */
2375 while (t > s && isspace(t[-1])) t--;
2376 while (tt > h->text && isspace(tt[-1])) tt--;
2378 /* Add the address that failed to the error message, since in a
2379 header with very many addresses it is sometimes hard to spot
2380 which one is at fault. However, limit the amount of address to
2381 quote - cases have been seen where, for example, a missing double
2382 quote in a humungous To: header creates an "address" that is longer
2383 than string_sprintf can handle. */
2392 /* deconst cast ok as we're passing a non-const to string_printing() */
2393 *msgptr = US string_printing(
2394 string_sprintf("%s: failing address in \"%.*s:\" header %s: %.*s",
2395 errmess, tt - h->text, h->text, verb, len, s));
2398 break; /* Out of address loop */
2401 /* Advance to the next address */
2403 s = ss + (terminator? 1:0);
2404 while (isspace(*s)) s++;
2405 } /* Next address */
2407 parse_allow_group = FALSE;
2408 parse_found_group = FALSE;
2409 } /* Next header unless yield has been set FALSE */
2415 /*************************************************
2416 * Check header names for 8-bit characters *
2417 *************************************************/
2419 /* This function checks for invalid charcters in header names. See
2420 RFC 5322, 2.2. and RFC 6532, 3.
2423 msgptr where to put an error message
2430 verify_check_header_names_ascii(uschar **msgptr)
2435 for (h = header_list; h != NULL; h = h->next)
2437 colon = Ustrchr(h->text, ':');
2438 for(s = h->text; s < colon; s++)
2440 if ((*s < 33) || (*s > 126))
2442 *msgptr = string_sprintf("Invalid character in header \"%.*s\" found",
2443 colon - h->text, h->text);
2451 /*************************************************
2452 * Check for blind recipients *
2453 *************************************************/
2455 /* This function checks that every (envelope) recipient is mentioned in either
2456 the To: or Cc: header lines, thus detecting blind carbon copies.
2458 There are two ways of scanning that could be used: either scan the header lines
2459 and tick off the recipients, or scan the recipients and check the header lines.
2460 The original proposed patch did the former, but I have chosen to do the latter,
2461 because (a) it requires no memory and (b) will use fewer resources when there
2462 are many addresses in To: and/or Cc: and only one or two envelope recipients.
2465 Returns: OK if there are no blind recipients
2466 FAIL if there is at least one blind recipient
2470 verify_check_notblind(void)
2473 for (i = 0; i < recipients_count; i++)
2477 uschar *address = recipients_list[i].address;
2479 for (h = header_list; !found && h != NULL; h = h->next)
2483 if (h->type != htype_to && h->type != htype_cc) continue;
2485 colon = Ustrchr(h->text, ':');
2487 while (isspace(*s)) s++;
2489 /* Loop for multiple addresses in the header, enabling group syntax. Note
2490 that we have to reset this after the header has been scanned. */
2492 parse_allow_group = TRUE;
2496 uschar *ss = parse_find_address_end(s, FALSE);
2497 uschar *recipient,*errmess;
2498 int terminator = *ss;
2499 int start, end, domain;
2501 /* Temporarily terminate the string at this point, and extract the
2502 operative address within, allowing group syntax. */
2505 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2508 /* If we found a valid recipient that has a domain, compare it with the
2509 envelope recipient. Local parts are compared case-sensitively, domains
2510 case-insensitively. By comparing from the start with length "domain", we
2511 include the "@" at the end, which ensures that we are comparing the whole
2512 local part of each address. */
2514 if (recipient != NULL && domain != 0)
2516 found = Ustrncmp(recipient, address, domain) == 0 &&
2517 strcmpic(recipient + domain, address + domain) == 0;
2521 /* Advance to the next address */
2523 s = ss + (terminator? 1:0);
2524 while (isspace(*s)) s++;
2525 } /* Next address */
2527 parse_allow_group = FALSE;
2528 parse_found_group = FALSE;
2529 } /* Next header (if found is false) */
2531 if (!found) return FAIL;
2532 } /* Next recipient */
2539 /*************************************************
2540 * Find if verified sender *
2541 *************************************************/
2543 /* Usually, just a single address is verified as the sender of the message.
2544 However, Exim can be made to verify other addresses as well (often related in
2545 some way), and this is useful in some environments. There may therefore be a
2546 chain of such addresses that have previously been tested. This function finds
2547 whether a given address is on the chain.
2549 Arguments: the address to be verified
2550 Returns: pointer to an address item, or NULL
2554 verify_checked_sender(uschar *sender)
2557 for (addr = sender_verified_list; addr != NULL; addr = addr->next)
2558 if (Ustrcmp(sender, addr->address) == 0) break;
2566 /*************************************************
2567 * Get valid header address *
2568 *************************************************/
2570 /* Scan the originator headers of the message, looking for an address that
2571 verifies successfully. RFC 822 says:
2573 o The "Sender" field mailbox should be sent notices of
2574 any problems in transport or delivery of the original
2575 messages. If there is no "Sender" field, then the
2576 "From" field mailbox should be used.
2578 o If the "Reply-To" field exists, then the reply should
2579 go to the addresses indicated in that field and not to
2580 the address(es) indicated in the "From" field.
2582 So we check a Sender field if there is one, else a Reply_to field, else a From
2583 field. As some strange messages may have more than one of these fields,
2584 especially if they are resent- fields, check all of them if there is more than
2588 user_msgptr points to where to put a user error message
2589 log_msgptr points to where to put a log error message
2590 callout timeout for callout check (passed to verify_address())
2591 callout_overall overall callout timeout (ditto)
2592 callout_connect connect callout timeout (ditto)
2593 se_mailfrom mailfrom for verify; NULL => ""
2594 pm_mailfrom sender for pm callout check (passed to verify_address())
2595 options callout options (passed to verify_address())
2596 verrno where to put the address basic_errno
2598 If log_msgptr is set to something without setting user_msgptr, the caller
2599 normally uses log_msgptr for both things.
2601 Returns: result of the verification attempt: OK, FAIL, or DEFER;
2602 FAIL is given if no appropriate headers are found
2606 verify_check_header_address(uschar **user_msgptr, uschar **log_msgptr,
2607 int callout, int callout_overall, int callout_connect, uschar *se_mailfrom,
2608 uschar *pm_mailfrom, int options, int *verrno)
2610 static int header_types[] = { htype_sender, htype_reply_to, htype_from };
2615 for (i = 0; i < 3 && !done; i++)
2618 for (h = header_list; h != NULL && !done; h = h->next)
2620 int terminator, new_ok;
2621 uschar *s, *ss, *endname;
2623 if (h->type != header_types[i]) continue;
2624 s = endname = Ustrchr(h->text, ':') + 1;
2626 /* Scan the addresses in the header, enabling group syntax. Note that we
2627 have to reset this after the header has been scanned. */
2629 parse_allow_group = TRUE;
2633 address_item *vaddr;
2635 while (isspace(*s) || *s == ',') s++;
2636 if (*s == 0) break; /* End of header */
2638 ss = parse_find_address_end(s, FALSE);
2640 /* The terminator is a comma or end of header, but there may be white
2641 space preceding it (including newline for the last address). Move back
2642 past any white space so we can check against any cached envelope sender
2643 address verifications. */
2645 while (isspace(ss[-1])) ss--;
2649 HDEBUG(D_verify) debug_printf("verifying %.*s header address %s\n",
2650 (int)(endname - h->text), h->text, s);
2652 /* See if we have already verified this address as an envelope sender,
2653 and if so, use the previous answer. */
2655 vaddr = verify_checked_sender(s);
2657 if (vaddr != NULL && /* Previously checked */
2658 (callout <= 0 || /* No callout needed; OR */
2659 vaddr->special_action > 256)) /* Callout was done */
2661 new_ok = vaddr->special_action & 255;
2662 HDEBUG(D_verify) debug_printf("previously checked as envelope sender\n");
2663 *ss = terminator; /* Restore shortened string */
2666 /* Otherwise we run the verification now. We must restore the shortened
2667 string before running the verification, so the headers are correct, in
2668 case there is any rewriting. */
2672 int start, end, domain;
2673 uschar *address = parse_extract_address(s, log_msgptr, &start, &end,
2678 /* If we found an empty address, just carry on with the next one, but
2679 kill the message. */
2681 if (address == NULL && Ustrcmp(*log_msgptr, "empty address") == 0)
2688 /* If verification failed because of a syntax error, fail this
2689 function, and ensure that the failing address gets added to the error
2692 if (address == NULL)
2695 while (ss > s && isspace(ss[-1])) ss--;
2696 *log_msgptr = string_sprintf("syntax error in '%.*s' header when "
2697 "scanning for sender: %s in \"%.*s\"",
2698 endname - h->text, h->text, *log_msgptr, ss - s, s);
2704 /* Else go ahead with the sender verification. But it isn't *the*
2705 sender of the message, so set vopt_fake_sender to stop sender_address
2706 being replaced after rewriting or qualification. */
2710 vaddr = deliver_make_addr(address, FALSE);
2711 new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender,
2712 callout, callout_overall, callout_connect, se_mailfrom,
2717 /* We now have the result, either newly found, or cached. If we are
2718 giving out error details, set a specific user error. This means that the
2719 last of these will be returned to the user if all three fail. We do not
2720 set a log message - the generic one below will be used. */
2724 *verrno = vaddr->basic_errno;
2725 if (smtp_return_error_details)
2727 *user_msgptr = string_sprintf("Rejected after DATA: "
2728 "could not verify \"%.*s\" header address\n%s: %s",
2729 endname - h->text, h->text, vaddr->address, vaddr->message);
2733 /* Success or defer */
2742 if (new_ok == DEFER) yield = DEFER;
2744 /* Move on to any more addresses in the header */
2747 } /* Next address */
2749 parse_allow_group = FALSE;
2750 parse_found_group = FALSE;
2751 } /* Next header, unless done */
2752 } /* Next header type unless done */
2754 if (yield == FAIL && *log_msgptr == NULL)
2755 *log_msgptr = US"there is no valid sender in any header line";
2757 if (yield == DEFER && *log_msgptr == NULL)
2758 *log_msgptr = US"all attempts to verify a sender in a header line deferred";
2766 /*************************************************
2767 * Get RFC 1413 identification *
2768 *************************************************/
2770 /* Attempt to get an id from the sending machine via the RFC 1413 protocol. If
2771 the timeout is set to zero, then the query is not done. There may also be lists
2772 of hosts and nets which are exempt. To guard against malefactors sending
2773 non-printing characters which could, for example, disrupt a message's headers,
2774 make sure the string consists of printing characters only.
2777 port the port to connect to; usually this is IDENT_PORT (113), but when
2778 running in the test harness with -bh a different value is used.
2782 Side effect: any received ident value is put in sender_ident (NULL otherwise)
2786 verify_get_ident(int port)
2788 int sock, host_af, qlen;
2789 int received_sender_port, received_interface_port, n;
2791 uschar buffer[2048];
2793 /* Default is no ident. Check whether we want to do an ident check for this
2796 sender_ident = NULL;
2797 if (rfc1413_query_timeout <= 0 || verify_check_host(&rfc1413_hosts) != OK)
2800 DEBUG(D_ident) debug_printf("doing ident callback\n");
2802 /* Set up a connection to the ident port of the remote host. Bind the local end
2803 to the incoming interface address. If the sender host address is an IPv6
2804 address, the incoming interface address will also be IPv6. */
2806 host_af = (Ustrchr(sender_host_address, ':') == NULL)? AF_INET : AF_INET6;
2807 sock = ip_socket(SOCK_STREAM, host_af);
2808 if (sock < 0) return;
2810 if (ip_bind(sock, host_af, interface_address, 0) < 0)
2812 DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n",
2817 if (ip_connect(sock, host_af, sender_host_address, port, rfc1413_query_timeout)
2820 if (errno == ETIMEDOUT && (log_extra_selector & LX_ident_timeout) != 0)
2822 log_write(0, LOG_MAIN, "ident connection to %s timed out",
2823 sender_host_address);
2827 DEBUG(D_ident) debug_printf("ident connection to %s failed: %s\n",
2828 sender_host_address, strerror(errno));
2833 /* Construct and send the query. */
2835 sprintf(CS buffer, "%d , %d\r\n", sender_host_port, interface_port);
2836 qlen = Ustrlen(buffer);
2837 if (send(sock, buffer, qlen, 0) < 0)
2839 DEBUG(D_ident) debug_printf("ident send failed: %s\n", strerror(errno));
2843 /* Read a response line. We put it into the rest of the buffer, using several
2844 recv() calls if necessary. */
2852 int size = sizeof(buffer) - (p - buffer);
2854 if (size <= 0) goto END_OFF; /* Buffer filled without seeing \n. */
2855 count = ip_recv(sock, p, size, rfc1413_query_timeout);
2856 if (count <= 0) goto END_OFF; /* Read error or EOF */
2858 /* Scan what we just read, to see if we have reached the terminating \r\n. Be
2859 generous, and accept a plain \n terminator as well. The only illegal
2862 for (pp = p; pp < p + count; pp++)
2864 if (*pp == 0) goto END_OFF; /* Zero octet not allowed */
2867 if (pp[-1] == '\r') pp--;
2869 goto GOT_DATA; /* Break out of both loops */
2873 /* Reached the end of the data without finding \n. Let the loop continue to
2874 read some more, if there is room. */
2881 /* We have received a line of data. Check it carefully. It must start with the
2882 same two port numbers that we sent, followed by data as defined by the RFC. For
2885 12345 , 25 : USERID : UNIX :root
2887 However, the amount of white space may be different to what we sent. In the
2888 "osname" field there may be several sub-fields, comma separated. The data we
2889 actually want to save follows the third colon. Some systems put leading spaces
2890 in it - we discard those. */
2892 if (sscanf(CS buffer + qlen, "%d , %d%n", &received_sender_port,
2893 &received_interface_port, &n) != 2 ||
2894 received_sender_port != sender_host_port ||
2895 received_interface_port != interface_port)
2898 p = buffer + qlen + n;
2899 while(isspace(*p)) p++;
2900 if (*p++ != ':') goto END_OFF;
2901 while(isspace(*p)) p++;
2902 if (Ustrncmp(p, "USERID", 6) != 0) goto END_OFF;
2904 while(isspace(*p)) p++;
2905 if (*p++ != ':') goto END_OFF;
2906 while (*p != 0 && *p != ':') p++;
2907 if (*p++ == 0) goto END_OFF;
2908 while(isspace(*p)) p++;
2909 if (*p == 0) goto END_OFF;
2911 /* The rest of the line is the data we want. We turn it into printing
2912 characters when we save it, so that it cannot mess up the format of any logging
2913 or Received: lines into which it gets inserted. We keep a maximum of 127
2914 characters. The deconst cast is ok as we fed a nonconst to string_printing() */
2916 sender_ident = US string_printing(string_copyn(p, 127));
2917 DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident);
2927 /*************************************************
2928 * Match host to a single host-list item *
2929 *************************************************/
2931 /* This function compares a host (name or address) against a single item
2932 from a host list. The host name gets looked up if it is needed and is not
2933 already known. The function is called from verify_check_this_host() via
2934 match_check_list(), which is why most of its arguments are in a single block.
2937 arg the argument block (see below)
2938 ss the host-list item
2939 valueptr where to pass back looked up data, or NULL
2940 error for error message when returning ERROR
2943 host_name (a) the host name, or
2944 (b) NULL, implying use sender_host_name and
2945 sender_host_aliases, looking them up if required, or
2946 (c) the empty string, meaning that only IP address matches
2948 host_address the host address
2949 host_ipv4 the IPv4 address taken from an IPv6 one
2953 DEFER lookup deferred
2954 ERROR (a) failed to find the host name or IP address, or
2955 (b) unknown lookup type specified, or
2956 (c) host name encountered when only IP addresses are
2961 check_host(void *arg, const uschar *ss, const uschar **valueptr, uschar **error)
2963 check_host_block *cb = (check_host_block *)arg;
2966 BOOL iplookup = FALSE;
2967 BOOL isquery = FALSE;
2968 BOOL isiponly = cb->host_name != NULL && cb->host_name[0] == 0;
2973 /* Optimize for the special case when the pattern is "*". */
2975 if (*ss == '*' && ss[1] == 0) return OK;
2977 /* If the pattern is empty, it matches only in the case when there is no host -
2978 this can occur in ACL checking for SMTP input using the -bs option. In this
2979 situation, the host address is the empty string. */
2981 if (cb->host_address[0] == 0) return (*ss == 0)? OK : FAIL;
2982 if (*ss == 0) return FAIL;
2984 /* If the pattern is precisely "@" then match against the primary host name,
2985 provided that host name matching is permitted; if it's "@[]" match against the
2986 local host's IP addresses. */
2992 if (isiponly) return ERROR;
2993 ss = primary_hostname;
2995 else if (Ustrcmp(ss, "@[]") == 0)
2997 ip_address_item *ip;
2998 for (ip = host_find_interfaces(); ip != NULL; ip = ip->next)
2999 if (Ustrcmp(ip->address, cb->host_address) == 0) return OK;
3004 /* If the pattern is an IP address, optionally followed by a bitmask count, do
3005 a (possibly masked) comparision with the current IP address. */
3007 if (string_is_ip_address(ss, &maskoffset) != 0)
3008 return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL);
3010 /* The pattern is not an IP address. A common error that people make is to omit
3011 one component of an IPv4 address, either by accident, or believing that, for
3012 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,
3013 which it isn't. (Those applications that do accept 1.2.3 as an IP address
3014 interpret it as 1.2.0.3 because the final component becomes 16-bit - this is an
3015 ancient specification.) To aid in debugging these cases, we give a specific
3016 error if the pattern contains only digits and dots or contains a slash preceded
3017 only by digits and dots (a slash at the start indicates a file name and of
3018 course slashes may be present in lookups, but not preceded only by digits and
3021 for (t = ss; isdigit(*t) || *t == '.'; t++);
3022 if (*t == 0 || (*t == '/' && t != ss))
3024 *error = US"malformed IPv4 address or address mask";
3028 /* See if there is a semicolon in the pattern */
3030 semicolon = Ustrchr(ss, ';');
3032 /* If we are doing an IP address only match, then all lookups must be IP
3033 address lookups, even if there is no "net-". */
3037 iplookup = semicolon != NULL;
3040 /* Otherwise, if the item is of the form net[n]-lookup;<file|query> then it is
3041 a lookup on a masked IP network, in textual form. We obey this code even if we
3042 have already set iplookup, so as to skip over the "net-" prefix and to set the
3043 mask length. The net- stuff really only applies to single-key lookups where the
3044 key is implicit. For query-style lookups the key is specified in the query.
3045 From release 4.30, the use of net- for query style is no longer needed, but we
3046 retain it for backward compatibility. */
3048 if (Ustrncmp(ss, "net", 3) == 0 && semicolon != NULL)
3051 for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0';
3052 if (mlen == 0 && t == ss+3) mlen = -1; /* No mask supplied */
3053 iplookup = (*t++ == '-');
3057 /* Do the IP address lookup if that is indeed what we have */
3065 uschar *filename, *key, *result;
3068 /* Find the search type */
3070 search_type = search_findtype(t, semicolon - t);
3072 if (search_type < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
3073 search_error_message);
3075 /* Adjust parameters for the type of lookup. For a query-style lookup, there
3076 is no file name, and the "key" is just the query. For query-style with a file
3077 name, we have to fish the file off the start of the query. For a single-key
3078 lookup, the key is the current IP address, masked appropriately, and
3079 reconverted to text form, with the mask appended. For IPv6 addresses, specify
3080 dot separators instead of colons, except when the lookup type is "iplsearch".
3083 if (mac_islookup(search_type, lookup_absfilequery))
3085 filename = semicolon + 1;
3087 while (*key != 0 && !isspace(*key)) key++;
3088 filename = string_copyn(filename, key - filename);
3089 while (isspace(*key)) key++;
3091 else if (mac_islookup(search_type, lookup_querystyle))
3094 key = semicolon + 1;
3096 else /* Single-key style */
3098 int sep = (Ustrcmp(lookup_list[search_type]->name, "iplsearch") == 0)?
3100 insize = host_aton(cb->host_address, incoming);
3101 host_mask(insize, incoming, mlen);
3102 (void)host_nmtoa(insize, incoming, mlen, buffer, sep);
3104 filename = semicolon + 1;
3107 /* Now do the actual lookup; note that there is no search_close() because
3108 of the caching arrangements. */
3110 handle = search_open(filename, search_type, 0, NULL, NULL);
3111 if (handle == NULL) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
3112 search_error_message);
3113 result = search_find(handle, filename, key, -1, NULL, 0, 0, NULL);
3114 if (valueptr != NULL) *valueptr = result;
3115 return (result != NULL)? OK : search_find_defer? DEFER: FAIL;
3118 /* The pattern is not an IP address or network reference of any kind. That is,
3119 it is a host name pattern. If this is an IP only match, there's an error in the
3124 *error = US"cannot match host name in match_ip list";
3128 /* Check the characters of the pattern to see if they comprise only letters,
3129 digits, full stops, and hyphens (the constituents of domain names). Allow
3130 underscores, as they are all too commonly found. Sigh. Also, if
3131 allow_utf8_domains is set, allow top-bit characters. */
3133 for (t = ss; *t != 0; t++)
3134 if (!isalnum(*t) && *t != '.' && *t != '-' && *t != '_' &&
3135 (!allow_utf8_domains || *t < 128)) break;
3137 /* If the pattern is a complete domain name, with no fancy characters, look up
3138 its IP address and match against that. Note that a multi-homed host will add
3139 items to the chain. */
3150 rc = host_find_byname(&h, NULL, HOST_FIND_QUALIFY_SINGLE, NULL, FALSE);
3151 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3154 for (hh = &h; hh != NULL; hh = hh->next)
3156 if (host_is_in_net(hh->address, cb->host_address, 0)) return OK;
3160 if (rc == HOST_FIND_AGAIN) return DEFER;
3161 *error = string_sprintf("failed to find IP address for %s", ss);
3165 /* Almost all subsequent comparisons require the host name, and can be done
3166 using the general string matching function. When this function is called for
3167 outgoing hosts, the name is always given explicitly. If it is NULL, it means we
3168 must use sender_host_name and its aliases, looking them up if necessary. */
3170 if (cb->host_name != NULL) /* Explicit host name given */
3171 return match_check_string(cb->host_name, ss, -1, TRUE, TRUE, TRUE,
3174 /* Host name not given; in principle we need the sender host name and its
3175 aliases. However, for query-style lookups, we do not need the name if the
3176 query does not contain $sender_host_name. From release 4.23, a reference to
3177 $sender_host_name causes it to be looked up, so we don't need to do the lookup
3180 if ((semicolon = Ustrchr(ss, ';')) != NULL)
3182 const uschar *affix;
3183 int partial, affixlen, starflags, id;
3186 id = search_findtype_partial(ss, &partial, &affix, &affixlen, &starflags);
3189 if (id < 0) /* Unknown lookup type */
3191 log_write(0, LOG_MAIN|LOG_PANIC, "%s in host list item \"%s\"",
3192 search_error_message, ss);
3195 isquery = mac_islookup(id, lookup_querystyle|lookup_absfilequery);
3200 switch(match_check_string(US"", ss, -1, TRUE, TRUE, TRUE, valueptr))
3203 case DEFER: return DEFER;
3204 default: return FAIL;
3208 /* Not a query-style lookup; must ensure the host name is present, and then we
3209 do a check on the name and all its aliases. */
3211 if (sender_host_name == NULL)
3213 HDEBUG(D_host_lookup)
3214 debug_printf("sender host name required, to match against %s\n", ss);
3215 if (host_lookup_failed || host_name_lookup() != OK)
3217 *error = string_sprintf("failed to find host name for %s",
3218 sender_host_address);;
3221 host_build_sender_fullhost();
3224 /* Match on the sender host name, using the general matching function */
3226 switch(match_check_string(sender_host_name, ss, -1, TRUE, TRUE, TRUE,
3230 case DEFER: return DEFER;
3233 /* If there are aliases, try matching on them. */
3235 aliases = sender_host_aliases;
3236 while (*aliases != NULL)
3238 switch(match_check_string(*aliases++, ss, -1, TRUE, TRUE, TRUE, valueptr))
3241 case DEFER: return DEFER;
3250 /*************************************************
3251 * Check a specific host matches a host list *
3252 *************************************************/
3254 /* This function is passed a host list containing items in a number of
3255 different formats and the identity of a host. Its job is to determine whether
3256 the given host is in the set of hosts defined by the list. The host name is
3257 passed as a pointer so that it can be looked up if needed and not already
3258 known. This is commonly the case when called from verify_check_host() to check
3259 an incoming connection. When called from elsewhere the host name should usually
3262 This function is now just a front end to match_check_list(), which runs common
3263 code for scanning a list. We pass it the check_host() function to perform a
3267 listptr pointer to the host list
3268 cache_bits pointer to cache for named lists, or NULL
3269 host_name the host name or NULL, implying use sender_host_name and
3270 sender_host_aliases, looking them up if required
3271 host_address the IP address
3272 valueptr if not NULL, data from a lookup is passed back here
3274 Returns: OK if the host is in the defined set
3275 FAIL if the host is not in the defined set,
3276 DEFER if a data lookup deferred (not a host lookup)
3278 If the host name was needed in order to make a comparison, and could not be
3279 determined from the IP address, the result is FAIL unless the item
3280 "+allow_unknown" was met earlier in the list, in which case OK is returned. */
3283 verify_check_this_host(const uschar **listptr, unsigned int *cache_bits,
3284 const uschar *host_name, const uschar *host_address, const uschar **valueptr)
3287 unsigned int *local_cache_bits = cache_bits;
3288 const uschar *save_host_address = deliver_host_address;
3289 check_host_block cb;
3290 cb.host_name = host_name;
3291 cb.host_address = host_address;
3293 if (valueptr != NULL) *valueptr = NULL;
3295 /* If the host address starts off ::ffff: it is an IPv6 address in
3296 IPv4-compatible mode. Find the IPv4 part for checking against IPv4
3299 cb.host_ipv4 = (Ustrncmp(host_address, "::ffff:", 7) == 0)?
3300 host_address + 7 : host_address;
3302 /* During the running of the check, put the IP address into $host_address. In
3303 the case of calls from the smtp transport, it will already be there. However,
3304 in other calls (e.g. when testing ignore_target_hosts), it won't. Just to be on
3305 the safe side, any existing setting is preserved, though as I write this
3306 (November 2004) I can't see any cases where it is actually needed. */
3308 deliver_host_address = host_address;
3309 rc = match_check_list(
3310 listptr, /* the list */
3311 0, /* separator character */
3312 &hostlist_anchor, /* anchor pointer */
3313 &local_cache_bits, /* cache pointer */
3314 check_host, /* function for testing */
3315 &cb, /* argument for function */
3316 MCL_HOST, /* type of check */
3317 (host_address == sender_host_address)?
3318 US"host" : host_address, /* text for debugging */
3319 valueptr); /* where to pass back data */
3320 deliver_host_address = save_host_address;
3327 /*************************************************
3328 * Check the given host item matches a list *
3329 *************************************************/
3331 verify_check_given_host(uschar **listptr, host_item *host)
3333 return verify_check_this_host(CUSS listptr, NULL, host->name, host->address, NULL);
3336 /*************************************************
3337 * Check the remote host matches a list *
3338 *************************************************/
3340 /* This is a front end to verify_check_this_host(), created because checking
3341 the remote host is a common occurrence. With luck, a good compiler will spot
3342 the tail recursion and optimize it. If there's no host address, this is
3343 command-line SMTP input - check against an empty string for the address.
3346 listptr pointer to the host list
3348 Returns: the yield of verify_check_this_host(),
3349 i.e. OK, FAIL, or DEFER
3353 verify_check_host(uschar **listptr)
3355 return verify_check_this_host(CUSS listptr, sender_host_cache, NULL,
3356 (sender_host_address == NULL)? US"" : sender_host_address, NULL);
3363 /*************************************************
3364 * Invert an IP address *
3365 *************************************************/
3367 /* Originally just used for DNS xBL lists, now also used for the
3368 reverse_ip expansion operator.
3371 buffer where to put the answer
3372 address the address to invert
3376 invert_address(uschar *buffer, uschar *address)
3379 uschar *bptr = buffer;
3381 /* If this is an IPv4 address mapped into IPv6 format, adjust the pointer
3382 to the IPv4 part only. */
3384 if (Ustrncmp(address, "::ffff:", 7) == 0) address += 7;
3386 /* Handle IPv4 address: when HAVE_IPV6 is false, the result of host_aton() is
3389 if (host_aton(address, bin) == 1)
3393 for (i = 0; i < 4; i++)
3395 sprintf(CS bptr, "%d.", x & 255);
3396 while (*bptr) bptr++;
3401 /* Handle IPv6 address. Actually, as far as I know, there are no IPv6 addresses
3402 in any DNS black lists, and the format in which they will be looked up is
3403 unknown. This is just a guess. */
3409 for (j = 3; j >= 0; j--)
3412 for (i = 0; i < 8; i++)
3414 sprintf(CS bptr, "%x.", x & 15);
3415 while (*bptr) bptr++;
3422 /* Remove trailing period -- this is needed so that both arbitrary
3423 dnsbl keydomains and inverted addresses may be combined with the
3424 same format string, "%s.%s" */
3431 /*************************************************
3432 * Perform a single dnsbl lookup *
3433 *************************************************/
3435 /* This function is called from verify_check_dnsbl() below. It is also called
3436 recursively from within itself when domain and domain_txt are different
3437 pointers, in order to get the TXT record from the alternate domain.
3440 domain the outer dnsbl domain
3441 domain_txt alternate domain to lookup TXT record on success; when the
3442 same domain is to be used, domain_txt == domain (that is,
3443 the pointers must be identical, not just the text)
3444 keydomain the current keydomain (for debug message)
3445 prepend subdomain to lookup (like keydomain, but
3446 reversed if IP address)
3447 iplist the list of matching IP addresses, or NULL for "any"
3448 bitmask true if bitmask matching is wanted
3449 match_type condition for 'succeed' result
3450 0 => Any RR in iplist (=)
3451 1 => No RR in iplist (!=)
3452 2 => All RRs in iplist (==)
3453 3 => Some RRs not in iplist (!==)
3454 the two bits are defined as MT_NOT and MT_ALL
3455 defer_return what to return for a defer
3457 Returns: OK if lookup succeeded
3462 one_check_dnsbl(uschar *domain, uschar *domain_txt, uschar *keydomain,
3463 uschar *prepend, uschar *iplist, BOOL bitmask, int match_type,
3469 dnsbl_cache_block *cb;
3470 int old_pool = store_pool;
3471 uschar query[256]; /* DNS domain max length */
3473 /* Construct the specific query domainname */
3475 if (!string_format(query, sizeof(query), "%s.%s", prepend, domain))
3477 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
3478 "(ignored): %s...", query);
3482 /* Look for this query in the cache. */
3484 t = tree_search(dnsbl_cache, query);
3486 /* If not cached from a previous lookup, we must do a DNS lookup, and
3487 cache the result in permanent memory. */
3491 store_pool = POOL_PERM;
3493 /* Set up a tree entry to cache the lookup */
3495 t = store_get(sizeof(tree_node) + Ustrlen(query));
3496 Ustrcpy(t->name, query);
3497 t->data.ptr = cb = store_get(sizeof(dnsbl_cache_block));
3498 (void)tree_insertnode(&dnsbl_cache, t);
3500 /* Do the DNS loopup . */
3502 HDEBUG(D_dnsbl) debug_printf("new DNS lookup for %s\n", query);
3503 cb->rc = dns_basic_lookup(&dnsa, query, T_A);
3504 cb->text_set = FALSE;
3508 /* If the lookup succeeded, cache the RHS address. The code allows for
3509 more than one address - this was for complete generality and the possible
3510 use of A6 records. However, A6 records have been reduced to experimental
3511 status (August 2001) and may die out. So they may never get used at all,
3512 let alone in dnsbl records. However, leave the code here, just in case.
3514 Quite apart from one A6 RR generating multiple addresses, there are DNS
3515 lists that return more than one A record, so we must handle multiple
3516 addresses generated in that way as well. */
3518 if (cb->rc == DNS_SUCCEED)
3521 dns_address **addrp = &(cb->rhs);
3522 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
3524 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3526 if (rr->type == T_A)
3528 dns_address *da = dns_address_from_rr(&dnsa, rr);
3532 while (da->next != NULL) da = da->next;
3533 addrp = &(da->next);
3538 /* If we didn't find any A records, change the return code. This can
3539 happen when there is a CNAME record but there are no A records for what
3542 if (cb->rhs == NULL) cb->rc = DNS_NODATA;
3545 store_pool = old_pool;
3548 /* Previous lookup was cached */
3552 HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
3556 /* We now have the result of the DNS lookup, either newly done, or cached
3557 from a previous call. If the lookup succeeded, check against the address
3558 list if there is one. This may be a positive equality list (introduced by
3559 "="), a negative equality list (introduced by "!="), a positive bitmask
3560 list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/
3562 if (cb->rc == DNS_SUCCEED)
3564 dns_address *da = NULL;
3565 uschar *addlist = cb->rhs->address;
3567 /* For A and AAAA records, there may be multiple addresses from multiple
3568 records. For A6 records (currently not expected to be used) there may be
3569 multiple addresses from a single record. */
3571 for (da = cb->rhs->next; da != NULL; da = da->next)
3572 addlist = string_sprintf("%s, %s", addlist, da->address);
3574 HDEBUG(D_dnsbl) debug_printf("DNS lookup for %s succeeded (yielding %s)\n",
3577 /* Address list check; this can be either for equality, or via a bitmask.
3578 In the latter case, all the bits must match. */
3582 for (da = cb->rhs; da != NULL; da = da->next)
3586 const uschar *ptr = iplist;
3589 /* Handle exact matching */
3593 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))) != NULL)
3595 if (Ustrcmp(CS da->address, ip) == 0) break;
3599 /* Handle bitmask matching */
3606 /* At present, all known DNS blocking lists use A records, with
3607 IPv4 addresses on the RHS encoding the information they return. I
3608 wonder if this will linger on as the last vestige of IPv4 when IPv6
3609 is ubiquitous? Anyway, for now we use paranoia code to completely
3610 ignore IPv6 addresses. The default mask is 0, which always matches.
3611 We change this only for IPv4 addresses in the list. */
3613 if (host_aton(da->address, address) == 1) mask = address[0];
3615 /* Scan the returned addresses, skipping any that are IPv6 */
3617 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))) != NULL)
3619 if (host_aton(ip, address) != 1) continue;
3620 if ((address[0] & mask) == address[0]) break;
3626 (a) An IP address in an any ('=') list matched, or
3627 (b) No IP address in an all ('==') list matched
3629 then we're done searching. */
3631 if (((match_type & MT_ALL) != 0) == (res == NULL)) break;
3634 /* If da == NULL, either
3636 (a) No IP address in an any ('=') list matched, or
3637 (b) An IP address in an all ('==') list didn't match
3639 so behave as if the DNSBL lookup had not succeeded, i.e. the host is not on
3642 if ((match_type == MT_NOT || match_type == MT_ALL) != (da == NULL))
3650 res = US"was no match";
3653 res = US"was an exclude match";
3656 res = US"was an IP address that did not match";
3659 res = US"were no IP addresses that did not match";
3662 debug_printf("=> but we are not accepting this block class because\n");
3663 debug_printf("=> there %s for %s%c%s\n",
3665 ((match_type & MT_ALL) == 0)? "" : "=",
3666 bitmask? '&' : '=', iplist);
3672 /* Either there was no IP list, or the record matched, implying that the
3673 domain is on the list. We now want to find a corresponding TXT record. If an
3674 alternate domain is specified for the TXT record, call this function
3675 recursively to look that up; this has the side effect of re-checking that
3676 there is indeed an A record at the alternate domain. */
3678 if (domain_txt != domain)
3679 return one_check_dnsbl(domain_txt, domain_txt, keydomain, prepend, NULL,
3680 FALSE, match_type, defer_return);
3682 /* If there is no alternate domain, look up a TXT record in the main domain
3683 if it has not previously been cached. */
3687 cb->text_set = TRUE;
3688 if (dns_basic_lookup(&dnsa, query, T_TXT) == DNS_SUCCEED)
3691 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
3693 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3694 if (rr->type == T_TXT) break;
3697 int len = (rr->data)[0];
3698 if (len > 511) len = 127;
3699 store_pool = POOL_PERM;
3700 cb->text = string_sprintf("%.*s", len, (const uschar *)(rr->data+1));
3701 store_pool = old_pool;
3706 dnslist_value = addlist;
3707 dnslist_text = cb->text;
3711 /* There was a problem with the DNS lookup */
3713 if (cb->rc != DNS_NOMATCH && cb->rc != DNS_NODATA)
3715 log_write(L_dnslist_defer, LOG_MAIN,
3716 "DNS list lookup defer (probably timeout) for %s: %s", query,
3717 (defer_return == OK)? US"assumed in list" :
3718 (defer_return == FAIL)? US"assumed not in list" :
3719 US"returned DEFER");
3720 return defer_return;
3723 /* No entry was found in the DNS; continue for next domain */
3727 debug_printf("DNS lookup for %s failed\n", query);
3728 debug_printf("=> that means %s is not listed at %s\n",
3738 /*************************************************
3739 * Check host against DNS black lists *
3740 *************************************************/
3742 /* This function runs checks against a list of DNS black lists, until one
3743 matches. Each item on the list can be of the form
3745 domain=ip-address/key
3747 The domain is the right-most domain that is used for the query, for example,
3748 blackholes.mail-abuse.org. If the IP address is present, there is a match only
3749 if the DNS lookup returns a matching IP address. Several addresses may be
3750 given, comma-separated, for example: x.y.z=127.0.0.1,127.0.0.2.
3752 If no key is given, what is looked up in the domain is the inverted IP address
3753 of the current client host. If a key is given, it is used to construct the
3754 domain for the lookup. For example:
3756 dsn.rfc-ignorant.org/$sender_address_domain
3758 After finding a match in the DNS, the domain is placed in $dnslist_domain, and
3759 then we check for a TXT record for an error message, and if found, save its
3760 value in $dnslist_text. We also cache everything in a tree, to optimize
3763 The TXT record is normally looked up in the same domain as the A record, but
3764 when many lists are combined in a single DNS domain, this will not be a very
3765 specific message. It is possible to specify a different domain for looking up
3766 TXT records; this is given before the main domain, comma-separated. For
3769 dnslists = http.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.2 : \
3770 socks.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.3
3772 The caching ensures that only one lookup in dnsbl.sorbs.net is done.
3774 Note: an address for testing RBL is 192.203.178.39
3775 Note: an address for testing DUL is 192.203.178.4
3776 Note: a domain for testing RFCI is example.tld.dsn.rfc-ignorant.org
3779 listptr the domain/address/data list
3781 Returns: OK successful lookup (i.e. the address is on the list), or
3782 lookup deferred after +include_unknown
3783 FAIL name not found, or no data found for the given type, or
3784 lookup deferred after +exclude_unknown (default)
3785 DEFER lookup failure, if +defer_unknown was set
3789 verify_check_dnsbl(const uschar **listptr)
3792 int defer_return = FAIL;
3793 const uschar *list = *listptr;
3796 uschar buffer[1024];
3797 uschar revadd[128]; /* Long enough for IPv6 address */
3799 /* Indicate that the inverted IP address is not yet set up */
3803 /* In case this is the first time the DNS resolver is being used. */
3805 dns_init(FALSE, FALSE, FALSE); /*XXX dnssec? */
3807 /* Loop through all the domains supplied, until something matches */
3809 while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
3812 BOOL bitmask = FALSE;
3819 HDEBUG(D_dnsbl) debug_printf("DNS list check: %s\n", domain);
3821 /* Deal with special values that change the behaviour on defer */
3823 if (domain[0] == '+')
3825 if (strcmpic(domain, US"+include_unknown") == 0) defer_return = OK;
3826 else if (strcmpic(domain, US"+exclude_unknown") == 0) defer_return = FAIL;
3827 else if (strcmpic(domain, US"+defer_unknown") == 0) defer_return = DEFER;
3829 log_write(0, LOG_MAIN|LOG_PANIC, "unknown item in dnslist (ignored): %s",
3834 /* See if there's explicit data to be looked up */
3836 key = Ustrchr(domain, '/');
3837 if (key != NULL) *key++ = 0;
3839 /* See if there's a list of addresses supplied after the domain name. This is
3840 introduced by an = or a & character; if preceded by = we require all matches
3841 and if preceded by ! we invert the result. */
3843 iplist = Ustrchr(domain, '=');
3847 iplist = Ustrchr(domain, '&');
3850 if (iplist != NULL) /* Found either = or & */
3852 if (iplist > domain && iplist[-1] == '!') /* Handle preceding ! */
3854 match_type |= MT_NOT;
3858 *iplist++ = 0; /* Terminate domain, move on */
3860 /* If we found = (bitmask == FALSE), check for == or =& */
3862 if (!bitmask && (*iplist == '=' || *iplist == '&'))
3864 bitmask = *iplist++ == '&';
3865 match_type |= MT_ALL;
3869 /* If there is a comma in the domain, it indicates that a second domain for
3870 looking up TXT records is provided, before the main domain. Otherwise we must
3871 set domain_txt == domain. */
3873 domain_txt = domain;
3874 comma = Ustrchr(domain, ',');
3881 /* Check that what we have left is a sensible domain name. There is no reason
3882 why these domains should in fact use the same syntax as hosts and email
3883 domains, but in practice they seem to. However, there is little point in
3884 actually causing an error here, because that would no doubt hold up incoming
3885 mail. Instead, I'll just log it. */
3887 for (s = domain; *s != 0; s++)
3889 if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_')
3891 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
3892 "strange characters - is this right?", domain);
3897 /* Check the alternate domain if present */
3899 if (domain_txt != domain) for (s = domain_txt; *s != 0; s++)
3901 if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_')
3903 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
3904 "strange characters - is this right?", domain_txt);
3909 /* If there is no key string, construct the query by adding the domain name
3910 onto the inverted host address, and perform a single DNS lookup. */
3914 if (sender_host_address == NULL) return FAIL; /* can never match */
3915 if (revadd[0] == 0) invert_address(revadd, sender_host_address);
3916 rc = one_check_dnsbl(domain, domain_txt, sender_host_address, revadd,
3917 iplist, bitmask, match_type, defer_return);
3920 dnslist_domain = string_copy(domain_txt);
3921 dnslist_matched = string_copy(sender_host_address);
3922 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
3923 sender_host_address, dnslist_domain);
3925 if (rc != FAIL) return rc; /* OK or DEFER */
3928 /* If there is a key string, it can be a list of domains or IP addresses to
3929 be concatenated with the main domain. */
3936 uschar keybuffer[256];
3937 uschar keyrevadd[128];
3939 while ((keydomain = string_nextinlist(CUSS &key, &keysep, keybuffer,
3940 sizeof(keybuffer))) != NULL)
3942 uschar *prepend = keydomain;
3944 if (string_is_ip_address(keydomain, NULL) != 0)
3946 invert_address(keyrevadd, keydomain);
3947 prepend = keyrevadd;
3950 rc = one_check_dnsbl(domain, domain_txt, keydomain, prepend, iplist,
3951 bitmask, match_type, defer_return);
3955 dnslist_domain = string_copy(domain_txt);
3956 dnslist_matched = string_copy(keydomain);
3957 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
3958 keydomain, dnslist_domain);
3962 /* If the lookup deferred, remember this fact. We keep trying the rest
3963 of the list to see if we get a useful result, and if we don't, we return
3964 DEFER at the end. */
3966 if (rc == DEFER) defer = TRUE;
3967 } /* continue with next keystring domain/address */
3969 if (defer) return DEFER;
3971 } /* continue with next dnsdb outer domain */
3978 /* End of verify.c */