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,
646 if (inblock.sock < 0)
648 addr->message = string_sprintf("could not connect to %s [%s]: %s",
649 host->name, host->address, strerror(errno));
650 transport_name = NULL;
651 deliver_host = deliver_host_address = NULL;
652 deliver_domain = save_deliver_domain;
656 /* Expand the helo_data string to find the host name to use. */
658 if (tf->helo_data != NULL)
660 uschar *s = expand_string(tf->helo_data);
662 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: failed to expand transport's "
663 "helo_data value for callout: %s", addr->address,
664 expand_string_message);
665 else active_hostname = s;
668 /* Wait for initial response, and send HELO. The smtp_write_command()
669 function leaves its command in big_buffer. This is used in error responses.
670 Initialize it in case the connection is rejected. */
672 Ustrcpy(big_buffer, "initial connection");
674 /* Unless ssl-on-connect, wait for the initial greeting */
678 if (!smtps || (smtps && tls_out.active >= 0))
681 if (!(done= smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), '2', callout)))
682 goto RESPONSE_FAILED;
684 #ifdef EXPERIMENTAL_EVENT
685 lookup_dnssec_authenticated = host->dnssec==DS_YES ? US"yes"
686 : host->dnssec==DS_NO ? US"no" : NULL;
687 if (event_raise(addr->transport->event_action,
688 US"smtp:connect", responsebuffer))
690 lookup_dnssec_authenticated = NULL;
691 /* Logging? Debug? */
692 goto RESPONSE_FAILED;
694 lookup_dnssec_authenticated = NULL;
698 /* Not worth checking greeting line for ESMTP support */
699 if (!(esmtp = verify_check_given_host(&ob->hosts_avoid_esmtp, host) != OK))
701 debug_printf("not sending EHLO (host matches hosts_avoid_esmtp)\n");
706 if (smtps && tls_out.active < 0) /* ssl-on-connect, first pass */
709 ob->tls_tempfail_tryclear = FALSE;
711 else /* all other cases */
716 if (!(done= smtp_write_command(&outblock, FALSE, "%s %s\r\n",
717 !esmtp? "HELO" : lmtp? "LHLO" : "EHLO", active_hostname) >= 0))
719 if (!smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), '2', callout))
721 if (errno != 0 || responsebuffer[0] == 0 || lmtp || !esmtp || tls_out.active >= 0)
724 goto RESPONSE_FAILED;
730 goto esmtp_retry; /* fallback to HELO */
733 /* Set tls_offered if the response to EHLO specifies support for STARTTLS. */
735 if (esmtp && !suppress_tls && tls_out.active < 0)
737 if (regex_STARTTLS == NULL) regex_STARTTLS =
738 regex_must_compile(US"\\n250[\\s\\-]STARTTLS(\\s|\\n|$)", FALSE, TRUE);
740 tls_offered = pcre_exec(regex_STARTTLS, NULL, CS responsebuffer,
741 Ustrlen(responsebuffer), 0, PCRE_EOPT, NULL, 0) >= 0;
748 /* If TLS is available on this connection attempt to
749 start up a TLS session, unless the host is in hosts_avoid_tls. If successful,
750 send another EHLO - the server may give a different answer in secure mode. We
751 use a separate buffer for reading the response to STARTTLS so that if it is
752 negative, the original EHLO data is available for subsequent analysis, should
753 the client not be required to use TLS. If the response is bad, copy the buffer
754 for error analysis. */
758 && verify_check_given_host(&ob->hosts_avoid_tls, host) != OK
759 && verify_check_given_host(&ob->hosts_verify_avoid_tls, host) != OK
762 uschar buffer2[4096];
764 && !(done= smtp_write_command(&outblock, FALSE, "STARTTLS\r\n") >= 0))
767 /* If there is an I/O error, transmission of this message is deferred. If
768 there is a temporary rejection of STARRTLS and tls_tempfail_tryclear is
769 false, we also defer. However, if there is a temporary rejection of STARTTLS
770 and tls_tempfail_tryclear is true, or if there is an outright rejection of
771 STARTTLS, we carry on. This means we will try to send the message in clear,
772 unless the host is in hosts_require_tls (tested below). */
774 if (!smtps && !smtp_read_response(&inblock, buffer2, sizeof(buffer2), '2',
775 ob->command_timeout))
777 if (errno != 0 || buffer2[0] == 0 ||
778 (buffer2[0] == '4' && !ob->tls_tempfail_tryclear))
780 Ustrncpy(responsebuffer, buffer2, sizeof(responsebuffer));
782 goto RESPONSE_FAILED;
786 /* STARTTLS accepted or ssl-on-connect: try to negotiate a TLS session. */
789 int oldtimeout = ob->command_timeout;
793 ob->command_timeout = callout;
794 rc = tls_client_start(inblock.sock, host, addr, addr->transport
795 # ifdef EXPERIMENTAL_DANE
796 , dane ? &tlsa_dnsa : NULL
799 ob->command_timeout = oldtimeout;
801 /* TLS negotiation failed; give an error. Try in clear on a new
802 connection, if the options permit it for this host. */
807 (void)close(inblock.sock);
808 # ifdef EXPERIMENTAL_EVENT
809 (void) event_raise(addr->transport->event_action,
810 US"tcp:close", NULL);
812 # ifdef EXPERIMENTAL_DANE
817 log_write(0, LOG_MAIN, "DANE attempt failed;"
818 " trying CA-root TLS to %s [%s] (not in hosts_require_dane)",
819 host->name, host->address);
826 if ( ob->tls_tempfail_tryclear
828 && verify_check_given_host(&ob->hosts_require_tls, host) != OK
831 log_write(0, LOG_MAIN, "TLS session failure:"
832 " delivering unencrypted to %s [%s] (not in hosts_require_tls)",
833 host->name, host->address);
835 goto tls_retry_connection;
839 /*save_errno = ERRNO_TLSFAILURE;*/
840 /*message = US"failure while setting up TLS session";*/
846 /* TLS session is set up. Copy info for logging. */
847 addr->cipher = tls_out.cipher;
848 addr->peerdn = tls_out.peerdn;
850 /* For SMTPS we need to wait for the initial OK response, then do HELO. */
852 goto smtps_redo_greeting;
854 /* For STARTTLS we need to redo EHLO */
859 /* If the host is required to use a secure channel, ensure that we have one. */
860 if (tls_out.active < 0)
862 # ifdef EXPERIMENTAL_DANE
865 verify_check_given_host(&ob->hosts_require_tls, host) == OK
868 /*save_errno = ERRNO_TLSREQUIRED;*/
869 log_write(0, LOG_MAIN,
870 "H=%s [%s]: a TLS session is required for this host, but %s",
871 host->name, host->address,
872 tls_offered ? "an attempt to start TLS failed"
873 : "the server did not offer TLS support");
878 #endif /*SUPPORT_TLS*/
880 done = TRUE; /* so far so good; have response to HELO */
882 /*XXX the EHLO response would be analyzed here for IGNOREQUOTA, SIZE, PIPELINING */
884 /* For now, transport_filter by cutthrough-delivery is not supported */
885 /* Need proper integration with the proper transport mechanism. */
886 if (cutthrough.delivery)
888 if (addr->transport->filter_command)
890 cutthrough.delivery = FALSE;
891 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of transport filter\n");
896 cutthrough.delivery = FALSE;
897 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of DKIM signing\n");
906 /* Clear down of the TLS, SMTP and TCP layers on error is handled below. */
908 /* Failure to accept HELO is cached; this blocks the whole domain for all
909 senders. I/O errors and defer responses are not cached. */
913 *failure_ptr = US"mail"; /* At or before MAIL */
914 if (errno == 0 && responsebuffer[0] == '5')
916 setflag(addr, af_verify_nsfail);
917 new_domain_record.result = ccache_reject;
921 /* If we haven't authenticated, but are required to, give up. */
924 else done = smtp_auth(responsebuffer, sizeof(responsebuffer),
925 addr, host, ob, esmtp, &inblock, &outblock) == OK &&
927 /* Copy AUTH info for logging */
928 ( (addr->authenticator = client_authenticator),
929 (addr->auth_id = client_authenticated_id),
931 /* Build a mail-AUTH string (re-using responsebuffer for convenience */
932 !smtp_mail_auth_str(responsebuffer, sizeof(responsebuffer), addr, ob)
935 ( (addr->auth_sndr = client_authenticated_sender),
937 /* Send the MAIL command */
938 (smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>%s\r\n",
939 from_address, responsebuffer) >= 0)
942 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
945 deliver_host = deliver_host_address = NULL;
946 deliver_domain = save_deliver_domain;
948 /* If the host does not accept MAIL FROM:<>, arrange to cache this
949 information, but again, don't record anything for an I/O error or a defer. Do
950 not cache rejections of MAIL when a non-empty sender has been used, because
951 that blocks the whole domain for all senders. */
955 *failure_ptr = US"mail"; /* At or before MAIL */
956 if (errno == 0 && responsebuffer[0] == '5')
958 setflag(addr, af_verify_nsfail);
959 if (from_address[0] == 0)
960 new_domain_record.result = ccache_reject_mfnull;
964 /* Otherwise, proceed to check a "random" address (if required), then the
965 given address, and the postmaster address (if required). Between each check,
966 issue RSET, because some servers accept only one recipient after MAIL
969 Before doing this, set the result in the domain cache record to "accept",
970 unless its previous value was ccache_reject_mfnull. In that case, the domain
971 rejects MAIL FROM:<> and we want to continue to remember that. When that is
972 the case, we have got here only in the case of a recipient verification with
973 a non-null sender. */
977 new_domain_record.result =
978 (old_domain_cache_result == ccache_reject_mfnull)?
979 ccache_reject_mfnull: ccache_accept;
981 /* Do the random local part check first */
983 if (random_local_part != NULL)
985 uschar randombuffer[1024];
987 smtp_write_command(&outblock, FALSE,
988 "RCPT TO:<%.1000s@%.1000s>\r\n", random_local_part,
989 addr->domain) >= 0 &&
990 smtp_read_response(&inblock, randombuffer,
991 sizeof(randombuffer), '2', callout);
993 /* Remember when we last did a random test */
995 new_domain_record.random_stamp = time(NULL);
997 /* If accepted, we aren't going to do any further tests below. */
1000 new_domain_record.random_result = ccache_accept;
1002 /* Otherwise, cache a real negative response, and get back to the right
1003 state to send RCPT. Unless there's some problem such as a dropped
1004 connection, we expect to succeed, because the commands succeeded above.
1005 However, some servers drop the connection after responding to an
1006 invalid recipient, so on (any) error we drop and remake the connection.
1009 else if (errno == 0)
1011 /* This would be ok for 1st rcpt a cutthrough, but no way to
1012 handle a subsequent. So refuse to support any */
1013 cancel_cutthrough_connection("random-recipient");
1015 if (randombuffer[0] == '5')
1016 new_domain_record.random_result = ccache_reject;
1019 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
1020 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
1023 smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>\r\n",
1024 from_address) >= 0 &&
1025 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
1031 debug_printf("problem after random/rset/mfrom; reopen conn\n");
1032 random_local_part = NULL;
1034 tls_close(FALSE, TRUE);
1036 (void)close(inblock.sock);
1037 #ifdef EXPERIMENTAL_EVENT
1038 (void) event_raise(addr->transport->event_action,
1039 US"tcp:close", NULL);
1041 goto tls_retry_connection;
1044 else done = FALSE; /* Some timeout/connection problem */
1045 } /* Random check */
1047 /* If the host is accepting all local parts, as determined by the "random"
1048 check, we don't need to waste time doing any further checking. */
1050 if (new_domain_record.random_result != ccache_accept && done)
1052 /* Get the rcpt_include_affixes flag from the transport if there is one,
1053 but assume FALSE if there is not. */
1056 smtp_write_command(&outblock, FALSE, "RCPT TO:<%.1000s>\r\n",
1057 transport_rcpt_address(addr,
1058 (addr->transport == NULL)? FALSE :
1059 addr->transport->rcpt_include_affixes)) >= 0 &&
1060 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
1064 new_address_record.result = ccache_accept;
1065 else if (errno == 0 && responsebuffer[0] == '5')
1067 *failure_ptr = US"recipient";
1068 new_address_record.result = ccache_reject;
1071 /* Do postmaster check if requested; if a full check is required, we
1072 check for RCPT TO:<postmaster> (no domain) in accordance with RFC 821. */
1074 if (done && pm_mailfrom != NULL)
1076 /* Could possibly shift before main verify, just above, and be ok
1077 for cutthrough. But no way to handle a subsequent rcpt, so just
1079 cancel_cutthrough_connection("postmaster verify");
1080 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of postmaster verify\n");
1083 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
1084 smtp_read_response(&inblock, responsebuffer,
1085 sizeof(responsebuffer), '2', callout) &&
1087 smtp_write_command(&outblock, FALSE,
1088 "MAIL FROM:<%s>\r\n", pm_mailfrom) >= 0 &&
1089 smtp_read_response(&inblock, responsebuffer,
1090 sizeof(responsebuffer), '2', callout) &&
1092 /* First try using the current domain */
1095 smtp_write_command(&outblock, FALSE,
1096 "RCPT TO:<postmaster@%.1000s>\r\n", addr->domain) >= 0 &&
1097 smtp_read_response(&inblock, responsebuffer,
1098 sizeof(responsebuffer), '2', callout)
1103 /* If that doesn't work, and a full check is requested,
1104 try without the domain. */
1107 (options & vopt_callout_fullpm) != 0 &&
1108 smtp_write_command(&outblock, FALSE,
1109 "RCPT TO:<postmaster>\r\n") >= 0 &&
1110 smtp_read_response(&inblock, responsebuffer,
1111 sizeof(responsebuffer), '2', callout)
1114 /* Sort out the cache record */
1116 new_domain_record.postmaster_stamp = time(NULL);
1119 new_domain_record.postmaster_result = ccache_accept;
1120 else if (errno == 0 && responsebuffer[0] == '5')
1122 *failure_ptr = US"postmaster";
1123 setflag(addr, af_verify_pmfail);
1124 new_domain_record.postmaster_result = ccache_reject;
1127 } /* Random not accepted */
1128 } /* MAIL FROM: accepted */
1130 /* For any failure of the main check, other than a negative response, we just
1131 close the connection and carry on. We can identify a negative response by the
1132 fact that errno is zero. For I/O errors it will be non-zero
1134 Set up different error texts for logging and for sending back to the caller
1135 as an SMTP response. Log in all cases, using a one-line format. For sender
1136 callouts, give a full response to the caller, but for recipient callouts,
1137 don't give the IP address because this may be an internal host whose identity
1138 is not to be widely broadcast. */
1142 if (errno == ETIMEDOUT)
1144 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
1147 else if (errno == 0)
1149 if (*responsebuffer == 0) Ustrcpy(responsebuffer, US"connection dropped");
1152 string_sprintf("response to \"%s\" from %s [%s] was: %s",
1153 big_buffer, host->name, host->address,
1154 string_printing(responsebuffer));
1156 addr->user_message = is_recipient?
1157 string_sprintf("Callout verification failed:\n%s", responsebuffer)
1159 string_sprintf("Called: %s\nSent: %s\nResponse: %s",
1160 host->address, big_buffer, responsebuffer);
1162 /* Hard rejection ends the process */
1164 if (responsebuffer[0] == '5') /* Address rejected */
1172 /* End the SMTP conversation and close the connection. */
1174 /* Cutthrough - on a successfull connect and recipient-verify with
1175 use-sender and we are 1st rcpt and have no cutthrough conn so far
1176 here is where we want to leave the conn open */
1177 if ( cutthrough.delivery
1181 && (options & (vopt_callout_recipsender|vopt_callout_recippmaster)) == vopt_callout_recipsender
1182 && !random_local_part
1184 && cutthrough.fd < 0
1188 cutthrough.fd = outblock.sock; /* We assume no buffer in use in the outblock */
1189 cutthrough.nrcpt = 1;
1190 cutthrough.interface = interface;
1191 cutthrough.host = *host;
1192 cutthrough.addr = *addr; /* Save the address_item for later logging */
1193 cutthrough.addr.next = NULL;
1194 cutthrough.addr.host_used = &cutthrough.host;
1196 *(cutthrough.addr.parent = store_get(sizeof(address_item))) =
1198 ctblock.buffer = ctbuffer;
1199 ctblock.buffersize = sizeof(ctbuffer);
1200 ctblock.ptr = ctbuffer;
1201 /* ctblock.cmd_count = 0; ctblock.authenticating = FALSE; */
1202 ctblock.sock = cutthrough.fd;
1206 /* Ensure no cutthrough on multiple address verifies */
1207 if (options & vopt_callout_recipsender)
1208 cancel_cutthrough_connection("multiple verify calls");
1209 if (send_quit) (void)smtp_write_command(&outblock, FALSE, "QUIT\r\n");
1212 tls_close(FALSE, TRUE);
1214 (void)close(inblock.sock);
1215 #ifdef EXPERIMENTAL_EVENT
1216 (void) event_raise(addr->transport->event_action,
1217 US"tcp:close", NULL);
1221 } /* Loop through all hosts, while !done */
1224 /* If we get here with done == TRUE, a successful callout happened, and yield
1225 will be set OK or FAIL according to the response to the RCPT command.
1226 Otherwise, we looped through the hosts but couldn't complete the business.
1227 However, there may be domain-specific information to cache in both cases.
1229 The value of the result field in the new_domain record is ccache_unknown if
1230 there was an error before or with MAIL FROM:, and errno was not zero,
1231 implying some kind of I/O error. We don't want to write the cache in that case.
1232 Otherwise the value is ccache_accept, ccache_reject, or ccache_reject_mfnull. */
1234 if (!callout_no_cache && new_domain_record.result != ccache_unknown)
1236 if ((dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE))
1239 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
1243 (void)dbfn_write(dbm_file, addr->domain, &new_domain_record,
1244 (int)sizeof(dbdata_callout_cache));
1245 HDEBUG(D_verify) debug_printf("wrote callout cache domain record:\n"
1246 " result=%d postmaster=%d random=%d\n",
1247 new_domain_record.result,
1248 new_domain_record.postmaster_result,
1249 new_domain_record.random_result);
1253 /* If a definite result was obtained for the callout, cache it unless caching
1258 if (!callout_no_cache && new_address_record.result != ccache_unknown)
1260 if (dbm_file == NULL)
1261 dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE);
1262 if (dbm_file == NULL)
1264 HDEBUG(D_verify) debug_printf("no callout cache available\n");
1268 (void)dbfn_write(dbm_file, address_key, &new_address_record,
1269 (int)sizeof(dbdata_callout_cache_address));
1270 HDEBUG(D_verify) debug_printf("wrote %s callout cache address record\n",
1271 (new_address_record.result == ccache_accept)? "positive" : "negative");
1276 /* Failure to connect to any host, or any response other than 2xx or 5xx is a
1277 temporary error. If there was only one host, and a response was received, leave
1278 it alone if supplying details. Otherwise, give a generic response. */
1282 uschar *dullmsg = string_sprintf("Could not complete %s verify callout",
1283 is_recipient? "recipient" : "sender");
1286 if (host_list->next != NULL || addr->message == NULL) addr->message = dullmsg;
1288 addr->user_message = (!smtp_return_error_details)? dullmsg :
1289 string_sprintf("%s for <%s>.\n"
1290 "The mail server(s) for the domain may be temporarily unreachable, or\n"
1291 "they may be permanently unreachable from this server. In the latter case,\n%s",
1292 dullmsg, addr->address,
1294 "the address will never be accepted."
1296 "you need to change the address or create an MX record for its domain\n"
1297 "if it is supposed to be generally accessible from the Internet.\n"
1298 "Talk to your mail administrator for details.");
1300 /* Force a specific error code */
1302 addr->basic_errno = ERRNO_CALLOUTDEFER;
1305 /* Come here from within the cache-reading code on fast-track exit. */
1308 if (dbm_file != NULL) dbfn_close(dbm_file);
1314 /* Called after recipient-acl to get a cutthrough connection open when
1315 one was requested and a recipient-verify wasn't subsequently done.
1318 open_cutthrough_connection( address_item * addr )
1322 /* Use a recipient-verify-callout to set up the cutthrough connection. */
1323 /* We must use a copy of the address for verification, because it might
1327 HDEBUG(D_acl) debug_printf("----------- %s cutthrough setup ------------\n",
1328 rcpt_count > 1 ? "more" : "start");
1329 (void) verify_address(&addr2, NULL,
1330 vopt_is_recipient | vopt_callout_recipsender | vopt_callout_no_cache,
1331 CUTTHROUGH_CMD_TIMEOUT, -1, -1,
1333 HDEBUG(D_acl) debug_printf("----------- end cutthrough setup ------------\n");
1339 /* Send given number of bytes from the buffer */
1341 cutthrough_send(int n)
1343 if(cutthrough.fd < 0)
1348 (tls_out.active == cutthrough.fd) ? tls_write(FALSE, ctblock.buffer, n) :
1350 send(cutthrough.fd, ctblock.buffer, n, 0) > 0
1353 transport_count += n;
1354 ctblock.ptr= ctblock.buffer;
1358 HDEBUG(D_transport|D_acl) debug_printf("cutthrough_send failed: %s\n", strerror(errno));
1365 _cutthrough_puts(uschar * cp, int n)
1369 if(ctblock.ptr >= ctblock.buffer+ctblock.buffersize)
1370 if(!cutthrough_send(ctblock.buffersize))
1373 *ctblock.ptr++ = *cp++;
1378 /* Buffered output of counted data block. Return boolean success */
1380 cutthrough_puts(uschar * cp, int n)
1382 if (cutthrough.fd < 0) return TRUE;
1383 if (_cutthrough_puts(cp, n)) return TRUE;
1384 cancel_cutthrough_connection("transmit failed");
1390 _cutthrough_flush_send(void)
1392 int n= ctblock.ptr-ctblock.buffer;
1395 if(!cutthrough_send(n))
1401 /* Send out any bufferred output. Return boolean success. */
1403 cutthrough_flush_send(void)
1405 if (_cutthrough_flush_send()) return TRUE;
1406 cancel_cutthrough_connection("transmit failed");
1412 cutthrough_put_nl(void)
1414 return cutthrough_puts(US"\r\n", 2);
1418 /* Get and check response from cutthrough target */
1420 cutthrough_response(char expect, uschar ** copy)
1422 smtp_inblock inblock;
1423 uschar inbuffer[4096];
1424 uschar responsebuffer[4096];
1426 inblock.buffer = inbuffer;
1427 inblock.buffersize = sizeof(inbuffer);
1428 inblock.ptr = inbuffer;
1429 inblock.ptrend = inbuffer;
1430 inblock.sock = cutthrough.fd;
1431 /* this relies on (inblock.sock == tls_out.active) */
1432 if(!smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), expect, CUTTHROUGH_DATA_TIMEOUT))
1433 cancel_cutthrough_connection("target timeout on read");
1438 *copy = cp = string_copy(responsebuffer);
1439 /* Trim the trailing end of line */
1440 cp += Ustrlen(responsebuffer);
1441 if(cp > *copy && cp[-1] == '\n') *--cp = '\0';
1442 if(cp > *copy && cp[-1] == '\r') *--cp = '\0';
1445 return responsebuffer[0];
1449 /* Negotiate dataphase with the cutthrough target, returning success boolean */
1451 cutthrough_predata(void)
1453 if(cutthrough.fd < 0)
1456 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> DATA\n");
1457 cutthrough_puts(US"DATA\r\n", 6);
1458 cutthrough_flush_send();
1460 /* Assume nothing buffered. If it was it gets ignored. */
1461 return cutthrough_response('3', NULL) == '3';
1465 /* fd and use_crlf args only to match write_chunk() */
1467 cutthrough_write_chunk(int fd, uschar * s, int len, BOOL use_crlf)
1470 while(s && (s2 = Ustrchr(s, '\n')))
1472 if(!cutthrough_puts(s, s2-s) || !cutthrough_put_nl())
1480 /* Buffered send of headers. Return success boolean. */
1481 /* Expands newlines to wire format (CR,NL). */
1482 /* Also sends header-terminating blank line. */
1484 cutthrough_headers_send(void)
1486 if(cutthrough.fd < 0)
1489 /* We share a routine with the mainline transport to handle header add/remove/rewrites,
1490 but having a separate buffered-output function (for now)
1492 HDEBUG(D_acl) debug_printf("----------- start cutthrough headers send -----------\n");
1494 if (!transport_headers_send(&cutthrough.addr, cutthrough.fd,
1495 cutthrough.addr.transport->add_headers,
1496 cutthrough.addr.transport->remove_headers,
1497 &cutthrough_write_chunk, TRUE,
1498 cutthrough.addr.transport->rewrite_rules,
1499 cutthrough.addr.transport->rewrite_existflags))
1502 HDEBUG(D_acl) debug_printf("----------- done cutthrough headers send ------------\n");
1508 close_cutthrough_connection(const char * why)
1510 if(cutthrough.fd >= 0)
1512 /* We could be sending this after a bunch of data, but that is ok as
1513 the only way to cancel the transfer in dataphase is to drop the tcp
1514 conn before the final dot.
1516 ctblock.ptr = ctbuffer;
1517 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> QUIT\n");
1518 _cutthrough_puts(US"QUIT\r\n", 6); /* avoid recursion */
1519 _cutthrough_flush_send();
1520 /* No wait for response */
1523 tls_close(FALSE, TRUE);
1525 (void)close(cutthrough.fd);
1527 HDEBUG(D_acl) debug_printf("----------- cutthrough shutdown (%s) ------------\n", why);
1529 ctblock.ptr = ctbuffer;
1533 cancel_cutthrough_connection(const char * why)
1535 close_cutthrough_connection(why);
1536 cutthrough.delivery = FALSE;
1542 /* Have senders final-dot. Send one to cutthrough target, and grab the response.
1543 Log an OK response as a transmission.
1544 Close the connection.
1545 Return smtp response-class digit.
1548 cutthrough_finaldot(void)
1551 address_item * addr;
1552 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> .\n");
1554 /* Assume data finshed with new-line */
1555 if( !cutthrough_puts(US".", 1)
1556 || !cutthrough_put_nl()
1557 || !cutthrough_flush_send()
1559 return cutthrough.addr.message;
1561 res = cutthrough_response('2', &cutthrough.addr.message);
1562 for (addr = &cutthrough.addr; addr; addr = addr->next)
1564 addr->message = cutthrough.addr.message;
1568 delivery_log(LOG_MAIN, addr, (int)'>', NULL);
1569 close_cutthrough_connection("delivered");
1573 delivery_log(LOG_MAIN, addr, 0,
1574 US"tmp-reject from cutthrough after DATA:");
1578 delivery_log(LOG_MAIN|LOG_REJECT, addr, 0,
1579 US"rejected after DATA:");
1586 return cutthrough.addr.message;
1591 /*************************************************
1592 * Copy error to toplevel address *
1593 *************************************************/
1595 /* This function is used when a verify fails or defers, to ensure that the
1596 failure or defer information is in the original toplevel address. This applies
1597 when an address is redirected to a single new address, and the failure or
1598 deferral happens to the child address.
1601 vaddr the verify address item
1602 addr the final address item
1605 Returns: the value of YIELD
1609 copy_error(address_item *vaddr, address_item *addr, int yield)
1613 vaddr->message = addr->message;
1614 vaddr->user_message = addr->user_message;
1615 vaddr->basic_errno = addr->basic_errno;
1616 vaddr->more_errno = addr->more_errno;
1617 vaddr->p.address_data = addr->p.address_data;
1618 copyflag(vaddr, addr, af_pass_message);
1626 /**************************************************
1627 * printf that automatically handles TLS if needed *
1628 ***************************************************/
1630 /* This function is used by verify_address() as a substitute for all fprintf()
1631 calls; a direct fprintf() will not produce output in a TLS SMTP session, such
1632 as a response to an EXPN command. smtp_in.c makes smtp_printf available but
1633 that assumes that we always use the smtp_out FILE* when not using TLS or the
1634 ssl buffer when we are. Instead we take a FILE* parameter and check to see if
1635 that is smtp_out; if so, smtp_printf() with TLS support, otherwise regular
1639 f the candidate FILE* to write to
1640 format format string
1641 ... optional arguments
1647 static void PRINTF_FUNCTION(2,3)
1648 respond_printf(FILE *f, const char *format, ...)
1652 va_start(ap, format);
1653 if (smtp_out && (f == smtp_out))
1654 smtp_vprintf(format, ap);
1656 vfprintf(f, format, ap);
1662 /*************************************************
1663 * Verify an email address *
1664 *************************************************/
1666 /* This function is used both for verification (-bv and at other times) and
1667 address testing (-bt), which is indicated by address_test_mode being set.
1670 vaddr contains the address to verify; the next field in this block
1672 f if not NULL, write the result to this file
1673 options various option bits:
1674 vopt_fake_sender => this sender verify is not for the real
1675 sender (it was verify=sender=xxxx or an address from a
1676 header line) - rewriting must not change sender_address
1677 vopt_is_recipient => this is a recipient address, otherwise
1678 it's a sender address - this affects qualification and
1679 rewriting and messages from callouts
1680 vopt_qualify => qualify an unqualified address; else error
1681 vopt_expn => called from SMTP EXPN command
1682 vopt_success_on_redirect => when a new address is generated
1683 the verification instantly succeeds
1685 These ones are used by do_callout() -- the options variable
1688 vopt_callout_fullpm => if postmaster check, do full one
1689 vopt_callout_no_cache => don't use callout cache
1690 vopt_callout_random => do the "random" thing
1691 vopt_callout_recipsender => use real sender for recipient
1692 vopt_callout_recippmaster => use postmaster for recipient
1694 callout if > 0, specifies that callout is required, and gives timeout
1695 for individual commands
1696 callout_overall if > 0, gives overall timeout for the callout function;
1697 if < 0, a default is used (see do_callout())
1698 callout_connect the connection timeout for callouts
1699 se_mailfrom when callout is requested to verify a sender, use this
1700 in MAIL FROM; NULL => ""
1701 pm_mailfrom when callout is requested, if non-NULL, do the postmaster
1702 thing and use this as the sender address (may be "")
1704 routed if not NULL, set TRUE if routing succeeded, so we can
1705 distinguish between routing failed and callout failed
1707 Returns: OK address verified
1708 FAIL address failed to verify
1709 DEFER can't tell at present
1713 verify_address(address_item *vaddr, FILE *f, int options, int callout,
1714 int callout_overall, int callout_connect, uschar *se_mailfrom,
1715 uschar *pm_mailfrom, BOOL *routed)
1718 BOOL full_info = (f == NULL)? FALSE : (debug_selector != 0);
1719 BOOL is_recipient = (options & vopt_is_recipient) != 0;
1720 BOOL expn = (options & vopt_expn) != 0;
1721 BOOL success_on_redirect = (options & vopt_success_on_redirect) != 0;
1724 int verify_type = expn? v_expn :
1725 address_test_mode? v_none :
1726 is_recipient? v_recipient : v_sender;
1727 address_item *addr_list;
1728 address_item *addr_new = NULL;
1729 address_item *addr_remote = NULL;
1730 address_item *addr_local = NULL;
1731 address_item *addr_succeed = NULL;
1732 uschar **failure_ptr = is_recipient?
1733 &recipient_verify_failure : &sender_verify_failure;
1734 uschar *ko_prefix, *cr;
1735 uschar *address = vaddr->address;
1736 uschar *save_sender;
1737 uschar null_sender[] = { 0 }; /* Ensure writeable memory */
1739 /* Clear, just in case */
1741 *failure_ptr = NULL;
1743 /* Set up a prefix and suffix for error message which allow us to use the same
1744 output statements both in EXPN mode (where an SMTP response is needed) and when
1745 debugging with an output file. */
1749 ko_prefix = US"553 ";
1752 else ko_prefix = cr = US"";
1754 /* Add qualify domain if permitted; otherwise an unqualified address fails. */
1756 if (parse_find_at(address) == NULL)
1758 if ((options & vopt_qualify) == 0)
1761 respond_printf(f, "%sA domain is required for \"%s\"%s\n",
1762 ko_prefix, address, cr);
1763 *failure_ptr = US"qualify";
1766 address = rewrite_address_qualify(address, is_recipient);
1771 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1772 debug_printf("%s %s\n", address_test_mode? "Testing" : "Verifying", address);
1775 /* Rewrite and report on it. Clear the domain and local part caches - these
1776 may have been set by domains and local part tests during an ACL. */
1778 if (global_rewrite_rules != NULL)
1780 uschar *old = address;
1781 address = rewrite_address(address, is_recipient, FALSE,
1782 global_rewrite_rules, rewrite_existflags);
1785 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->localpart_cache[i] = 0;
1786 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->domain_cache[i] = 0;
1787 if (f != NULL && !expn) fprintf(f, "Address rewritten as: %s\n", address);
1791 /* If this is the real sender address, we must update sender_address at
1792 this point, because it may be referred to in the routers. */
1794 if ((options & (vopt_fake_sender|vopt_is_recipient)) == 0)
1795 sender_address = address;
1797 /* If the address was rewritten to <> no verification can be done, and we have
1798 to return OK. This rewriting is permitted only for sender addresses; for other
1799 addresses, such rewriting fails. */
1801 if (address[0] == 0) return OK;
1803 /* Flip the legacy TLS-related variables over to the outbound set in case
1804 they're used in the context of a transport used by verification. Reset them
1805 at exit from this routine. */
1807 tls_modify_variables(&tls_out);
1809 /* Save a copy of the sender address for re-instating if we change it to <>
1810 while verifying a sender address (a nice bit of self-reference there). */
1812 save_sender = sender_address;
1814 /* Update the address structure with the possibly qualified and rewritten
1815 address. Set it up as the starting address on the chain of new addresses. */
1817 vaddr->address = address;
1820 /* We need a loop, because an address can generate new addresses. We must also
1821 cope with generated pipes and files at the top level. (See also the code and
1822 comment in deliver.c.) However, it is usually the case that the router for
1823 user's .forward files has its verify flag turned off.
1825 If an address generates more than one child, the loop is used only when
1826 full_info is set, and this can only be set locally. Remote enquiries just get
1827 information about the top level address, not anything that it generated. */
1829 while (addr_new != NULL)
1832 address_item *addr = addr_new;
1834 addr_new = addr->next;
1839 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1840 debug_printf("Considering %s\n", addr->address);
1843 /* Handle generated pipe, file or reply addresses. We don't get these
1844 when handling EXPN, as it does only one level of expansion. */
1846 if (testflag(addr, af_pfr))
1853 if (addr->address[0] == '>')
1855 allow = testflag(addr, af_allow_reply);
1856 fprintf(f, "%s -> mail %s", addr->parent->address, addr->address + 1);
1860 allow = (addr->address[0] == '|')?
1861 testflag(addr, af_allow_pipe) : testflag(addr, af_allow_file);
1862 fprintf(f, "%s -> %s", addr->parent->address, addr->address);
1865 if (addr->basic_errno == ERRNO_BADTRANSPORT)
1866 fprintf(f, "\n*** Error in setting up pipe, file, or autoreply:\n"
1867 "%s\n", addr->message);
1869 fprintf(f, "\n transport = %s\n", addr->transport->name);
1871 fprintf(f, " *** forbidden ***\n");
1876 /* Just in case some router parameter refers to it. */
1878 return_path = (addr->p.errors_address != NULL)?
1879 addr->p.errors_address : sender_address;
1881 /* Split the address into domain and local part, handling the %-hack if
1882 necessary, and then route it. While routing a sender address, set
1883 $sender_address to <> because that is what it will be if we were trying to
1884 send a bounce to the sender. */
1886 if (routed != NULL) *routed = FALSE;
1887 if ((rc = deliver_split_address(addr)) == OK)
1889 if (!is_recipient) sender_address = null_sender;
1890 rc = route_address(addr, &addr_local, &addr_remote, &addr_new,
1891 &addr_succeed, verify_type);
1892 sender_address = save_sender; /* Put back the real sender */
1895 /* If routing an address succeeded, set the flag that remembers, for use when
1896 an ACL cached a sender verify (in case a callout fails). Then if routing set
1897 up a list of hosts or the transport has a host list, and the callout option
1898 is set, and we aren't in a host checking run, do the callout verification,
1899 and set another flag that notes that a callout happened. */
1903 if (routed != NULL) *routed = TRUE;
1906 host_item *host_list = addr->host_list;
1908 /* Make up some data for use in the case where there is no remote
1911 transport_feedback tf = {
1912 NULL, /* interface (=> any) */
1913 US"smtp", /* port */
1914 US"smtp", /* protocol */
1916 US"$smtp_active_hostname", /* helo_data */
1917 FALSE, /* hosts_override */
1918 FALSE, /* hosts_randomize */
1919 FALSE, /* gethostbyname */
1920 TRUE, /* qualify_single */
1921 FALSE /* search_parents */
1924 /* If verification yielded a remote transport, we want to use that
1925 transport's options, so as to mimic what would happen if we were really
1926 sending a message to this address. */
1928 if (addr->transport != NULL && !addr->transport->info->local)
1930 (void)(addr->transport->setup)(addr->transport, addr, &tf, 0, 0, NULL);
1932 /* If the transport has hosts and the router does not, or if the
1933 transport is configured to override the router's hosts, we must build a
1934 host list of the transport's hosts, and find the IP addresses */
1936 if (tf.hosts != NULL && (host_list == NULL || tf.hosts_override))
1939 const uschar *save_deliver_domain = deliver_domain;
1940 uschar *save_deliver_localpart = deliver_localpart;
1942 host_list = NULL; /* Ignore the router's hosts */
1944 deliver_domain = addr->domain;
1945 deliver_localpart = addr->local_part;
1946 s = expand_string(tf.hosts);
1947 deliver_domain = save_deliver_domain;
1948 deliver_localpart = save_deliver_localpart;
1952 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand list of hosts "
1953 "\"%s\" in %s transport for callout: %s", tf.hosts,
1954 addr->transport->name, expand_string_message);
1959 host_item *host, *nexthost;
1960 host_build_hostlist(&host_list, s, tf.hosts_randomize);
1962 /* Just ignore failures to find a host address. If we don't manage
1963 to find any addresses, the callout will defer. Note that more than
1964 one address may be found for a single host, which will result in
1965 additional host items being inserted into the chain. Hence we must
1966 save the next host first. */
1968 flags = HOST_FIND_BY_A;
1969 if (tf.qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
1970 if (tf.search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
1972 for (host = host_list; host != NULL; host = nexthost)
1974 nexthost = host->next;
1975 if (tf.gethostbyname ||
1976 string_is_ip_address(host->name, NULL) != 0)
1977 (void)host_find_byname(host, NULL, flags, NULL, TRUE);
1980 uschar * d_request = NULL, * d_require = NULL;
1981 if (Ustrcmp(addr->transport->driver_name, "smtp") == 0)
1983 smtp_transport_options_block * ob =
1984 (smtp_transport_options_block *)
1985 addr->transport->options_block;
1986 d_request = ob->dnssec_request_domains;
1987 d_require = ob->dnssec_require_domains;
1990 (void)host_find_bydns(host, NULL, flags, NULL, NULL, NULL,
1991 d_request, d_require, NULL, NULL);
1998 /* Can only do a callout if we have at least one host! If the callout
1999 fails, it will have set ${sender,recipient}_verify_failure. */
2001 if (host_list != NULL)
2003 HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n");
2004 if (host_checking && !host_checking_callout)
2007 debug_printf("... callout omitted by default when host testing\n"
2008 "(Use -bhc if you want the callouts to happen.)\n");
2013 deliver_set_expansions(addr);
2015 verify_mode = is_recipient ? US"R" : US"S";
2016 rc = do_callout(addr, host_list, &tf, callout, callout_overall,
2017 callout_connect, options, se_mailfrom, pm_mailfrom);
2023 HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor "
2024 "transport provided a host list\n");
2029 /* Otherwise, any failure is a routing failure */
2031 else *failure_ptr = US"route";
2033 /* A router may return REROUTED if it has set up a child address as a result
2034 of a change of domain name (typically from widening). In this case we always
2035 want to continue to verify the new child. */
2037 if (rc == REROUTED) continue;
2039 /* Handle hard failures */
2046 address_item *p = addr->parent;
2048 respond_printf(f, "%s%s %s", ko_prefix,
2049 full_info? addr->address : address,
2050 address_test_mode? "is undeliverable" : "failed to verify");
2051 if (!expn && admin_user)
2053 if (addr->basic_errno > 0)
2054 respond_printf(f, ": %s", strerror(addr->basic_errno));
2055 if (addr->message != NULL)
2056 respond_printf(f, ": %s", addr->message);
2059 /* Show parents iff doing full info */
2061 if (full_info) while (p != NULL)
2063 respond_printf(f, "%s\n <-- %s", cr, p->address);
2066 respond_printf(f, "%s\n", cr);
2068 cancel_cutthrough_connection("routing hard fail");
2072 yield = copy_error(vaddr, addr, FAIL);
2080 else if (rc == DEFER)
2085 address_item *p = addr->parent;
2086 respond_printf(f, "%s%s cannot be resolved at this time", ko_prefix,
2087 full_info? addr->address : address);
2088 if (!expn && admin_user)
2090 if (addr->basic_errno > 0)
2091 respond_printf(f, ": %s", strerror(addr->basic_errno));
2092 if (addr->message != NULL)
2093 respond_printf(f, ": %s", addr->message);
2094 else if (addr->basic_errno <= 0)
2095 respond_printf(f, ": unknown error");
2098 /* Show parents iff doing full info */
2100 if (full_info) while (p != NULL)
2102 respond_printf(f, "%s\n <-- %s", cr, p->address);
2105 respond_printf(f, "%s\n", cr);
2107 cancel_cutthrough_connection("routing soft fail");
2111 yield = copy_error(vaddr, addr, DEFER);
2114 else if (yield == OK) yield = DEFER;
2117 /* If we are handling EXPN, we do not want to continue to route beyond
2118 the top level (whose address is in "address"). */
2122 uschar *ok_prefix = US"250-";
2123 if (addr_new == NULL)
2125 if (addr_local == NULL && addr_remote == NULL)
2126 respond_printf(f, "250 mail to <%s> is discarded\r\n", address);
2128 respond_printf(f, "250 <%s>\r\n", address);
2130 else while (addr_new != NULL)
2132 address_item *addr2 = addr_new;
2133 addr_new = addr2->next;
2134 if (addr_new == NULL) ok_prefix = US"250 ";
2135 respond_printf(f, "%s<%s>\r\n", ok_prefix, addr2->address);
2141 /* Successful routing other than EXPN. */
2145 /* Handle successful routing when short info wanted. Otherwise continue for
2146 other (generated) addresses. Short info is the operational case. Full info
2147 can be requested only when debug_selector != 0 and a file is supplied.
2149 There is a conflict between the use of aliasing as an alternate email
2150 address, and as a sort of mailing list. If an alias turns the incoming
2151 address into just one address (e.g. J.Caesar->jc44) you may well want to
2152 carry on verifying the generated address to ensure it is valid when
2153 checking incoming mail. If aliasing generates multiple addresses, you
2154 probably don't want to do this. Exim therefore treats the generation of
2155 just a single new address as a special case, and continues on to verify the
2156 generated address. */
2158 if (!full_info && /* Stop if short info wanted AND */
2159 (((addr_new == NULL || /* No new address OR */
2160 addr_new->next != NULL || /* More than one new address OR */
2161 testflag(addr_new, af_pfr))) /* New address is pfr */
2163 (addr_new != NULL && /* At least one new address AND */
2164 success_on_redirect))) /* success_on_redirect is set */
2166 if (f != NULL) fprintf(f, "%s %s\n", address,
2167 address_test_mode? "is deliverable" : "verified");
2169 /* If we have carried on to verify a child address, we want the value
2170 of $address_data to be that of the child */
2172 vaddr->p.address_data = addr->p.address_data;
2177 } /* Loop for generated addresses */
2179 /* Display the full results of the successful routing, including any generated
2180 addresses. Control gets here only when full_info is set, which requires f not
2181 to be NULL, and this occurs only when a top-level verify is called with the
2182 debugging switch on.
2184 If there are no local and no remote addresses, and there were no pipes, files,
2185 or autoreplies, and there were no errors or deferments, the message is to be
2186 discarded, usually because of the use of :blackhole: in an alias file. */
2188 if (allok && addr_local == NULL && addr_remote == NULL)
2190 fprintf(f, "mail to %s is discarded\n", address);
2194 for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++)
2196 while (addr_list != NULL)
2198 address_item *addr = addr_list;
2199 address_item *p = addr->parent;
2200 addr_list = addr->next;
2202 fprintf(f, "%s", CS addr->address);
2203 #ifdef EXPERIMENTAL_SRS
2204 if(addr->p.srs_sender)
2205 fprintf(f, " [srs = %s]", addr->p.srs_sender);
2208 /* If the address is a duplicate, show something about it. */
2210 if (!testflag(addr, af_pfr))
2213 if ((tnode = tree_search(tree_duplicates, addr->unique)) != NULL)
2214 fprintf(f, " [duplicate, would not be delivered]");
2215 else tree_add_duplicate(addr->unique, addr);
2218 /* Now show its parents */
2222 fprintf(f, "\n <-- %s", p->address);
2227 /* Show router, and transport */
2229 fprintf(f, "router = %s, ", addr->router->name);
2230 fprintf(f, "transport = %s\n", (addr->transport == NULL)? US"unset" :
2231 addr->transport->name);
2233 /* Show any hosts that are set up by a router unless the transport
2234 is going to override them; fiddle a bit to get a nice format. */
2236 if (addr->host_list != NULL && addr->transport != NULL &&
2237 !addr->transport->overrides_hosts)
2242 for (h = addr->host_list; h != NULL; h = h->next)
2244 int len = Ustrlen(h->name);
2245 if (len > maxlen) maxlen = len;
2246 len = (h->address != NULL)? Ustrlen(h->address) : 7;
2247 if (len > maxaddlen) maxaddlen = len;
2249 for (h = addr->host_list; h != NULL; h = h->next)
2251 int len = Ustrlen(h->name);
2252 fprintf(f, " host %s ", h->name);
2253 while (len++ < maxlen) fprintf(f, " ");
2254 if (h->address != NULL)
2256 fprintf(f, "[%s] ", h->address);
2257 len = Ustrlen(h->address);
2259 else if (!addr->transport->info->local) /* Omit [unknown] for local */
2261 fprintf(f, "[unknown] ");
2265 while (len++ < maxaddlen) fprintf(f," ");
2266 if (h->mx >= 0) fprintf(f, "MX=%d", h->mx);
2267 if (h->port != PORT_NONE) fprintf(f, " port=%d", h->port);
2268 if (h->status == hstatus_unusable) fprintf(f, " ** unusable **");
2275 /* Yield will be DEFER or FAIL if any one address has, only for full_info (which is
2276 the -bv or -bt case). */
2279 tls_modify_variables(&tls_in);
2287 /*************************************************
2288 * Check headers for syntax errors *
2289 *************************************************/
2291 /* This function checks those header lines that contain addresses, and verifies
2292 that all the addresses therein are syntactially correct.
2295 msgptr where to put an error message
2302 verify_check_headers(uschar **msgptr)
2308 for (h = header_list; h != NULL && yield == OK; h = h->next)
2310 if (h->type != htype_from &&
2311 h->type != htype_reply_to &&
2312 h->type != htype_sender &&
2313 h->type != htype_to &&
2314 h->type != htype_cc &&
2315 h->type != htype_bcc)
2318 colon = Ustrchr(h->text, ':');
2320 while (isspace(*s)) s++;
2322 /* Loop for multiple addresses in the header, enabling group syntax. Note
2323 that we have to reset this after the header has been scanned. */
2325 parse_allow_group = TRUE;
2329 uschar *ss = parse_find_address_end(s, FALSE);
2330 uschar *recipient, *errmess;
2331 int terminator = *ss;
2332 int start, end, domain;
2334 /* Temporarily terminate the string at this point, and extract the
2335 operative address within, allowing group syntax. */
2338 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2341 /* Permit an unqualified address only if the message is local, or if the
2342 sending host is configured to be permitted to send them. */
2344 if (recipient != NULL && domain == 0)
2346 if (h->type == htype_from || h->type == htype_sender)
2348 if (!allow_unqualified_sender) recipient = NULL;
2352 if (!allow_unqualified_recipient) recipient = NULL;
2354 if (recipient == NULL) errmess = US"unqualified address not permitted";
2357 /* It's an error if no address could be extracted, except for the special
2358 case of an empty address. */
2360 if (recipient == NULL && Ustrcmp(errmess, "empty address") != 0)
2362 uschar *verb = US"is";
2367 /* Arrange not to include any white space at the end in the
2368 error message or the header name. */
2370 while (t > s && isspace(t[-1])) t--;
2371 while (tt > h->text && isspace(tt[-1])) tt--;
2373 /* Add the address that failed to the error message, since in a
2374 header with very many addresses it is sometimes hard to spot
2375 which one is at fault. However, limit the amount of address to
2376 quote - cases have been seen where, for example, a missing double
2377 quote in a humungous To: header creates an "address" that is longer
2378 than string_sprintf can handle. */
2387 /* deconst cast ok as we're passing a non-const to string_printing() */
2388 *msgptr = US string_printing(
2389 string_sprintf("%s: failing address in \"%.*s:\" header %s: %.*s",
2390 errmess, tt - h->text, h->text, verb, len, s));
2393 break; /* Out of address loop */
2396 /* Advance to the next address */
2398 s = ss + (terminator? 1:0);
2399 while (isspace(*s)) s++;
2400 } /* Next address */
2402 parse_allow_group = FALSE;
2403 parse_found_group = FALSE;
2404 } /* Next header unless yield has been set FALSE */
2410 /*************************************************
2411 * Check header names for 8-bit characters *
2412 *************************************************/
2414 /* This function checks for invalid charcters in header names. See
2415 RFC 5322, 2.2. and RFC 6532, 3.
2418 msgptr where to put an error message
2425 verify_check_header_names_ascii(uschar **msgptr)
2430 for (h = header_list; h != NULL; h = h->next)
2432 colon = Ustrchr(h->text, ':');
2433 for(s = h->text; s < colon; s++)
2435 if ((*s < 33) || (*s > 126))
2437 *msgptr = string_sprintf("Invalid character in header \"%.*s\" found",
2438 colon - h->text, h->text);
2446 /*************************************************
2447 * Check for blind recipients *
2448 *************************************************/
2450 /* This function checks that every (envelope) recipient is mentioned in either
2451 the To: or Cc: header lines, thus detecting blind carbon copies.
2453 There are two ways of scanning that could be used: either scan the header lines
2454 and tick off the recipients, or scan the recipients and check the header lines.
2455 The original proposed patch did the former, but I have chosen to do the latter,
2456 because (a) it requires no memory and (b) will use fewer resources when there
2457 are many addresses in To: and/or Cc: and only one or two envelope recipients.
2460 Returns: OK if there are no blind recipients
2461 FAIL if there is at least one blind recipient
2465 verify_check_notblind(void)
2468 for (i = 0; i < recipients_count; i++)
2472 uschar *address = recipients_list[i].address;
2474 for (h = header_list; !found && h != NULL; h = h->next)
2478 if (h->type != htype_to && h->type != htype_cc) continue;
2480 colon = Ustrchr(h->text, ':');
2482 while (isspace(*s)) s++;
2484 /* Loop for multiple addresses in the header, enabling group syntax. Note
2485 that we have to reset this after the header has been scanned. */
2487 parse_allow_group = TRUE;
2491 uschar *ss = parse_find_address_end(s, FALSE);
2492 uschar *recipient,*errmess;
2493 int terminator = *ss;
2494 int start, end, domain;
2496 /* Temporarily terminate the string at this point, and extract the
2497 operative address within, allowing group syntax. */
2500 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2503 /* If we found a valid recipient that has a domain, compare it with the
2504 envelope recipient. Local parts are compared case-sensitively, domains
2505 case-insensitively. By comparing from the start with length "domain", we
2506 include the "@" at the end, which ensures that we are comparing the whole
2507 local part of each address. */
2509 if (recipient != NULL && domain != 0)
2511 found = Ustrncmp(recipient, address, domain) == 0 &&
2512 strcmpic(recipient + domain, address + domain) == 0;
2516 /* Advance to the next address */
2518 s = ss + (terminator? 1:0);
2519 while (isspace(*s)) s++;
2520 } /* Next address */
2522 parse_allow_group = FALSE;
2523 parse_found_group = FALSE;
2524 } /* Next header (if found is false) */
2526 if (!found) return FAIL;
2527 } /* Next recipient */
2534 /*************************************************
2535 * Find if verified sender *
2536 *************************************************/
2538 /* Usually, just a single address is verified as the sender of the message.
2539 However, Exim can be made to verify other addresses as well (often related in
2540 some way), and this is useful in some environments. There may therefore be a
2541 chain of such addresses that have previously been tested. This function finds
2542 whether a given address is on the chain.
2544 Arguments: the address to be verified
2545 Returns: pointer to an address item, or NULL
2549 verify_checked_sender(uschar *sender)
2552 for (addr = sender_verified_list; addr != NULL; addr = addr->next)
2553 if (Ustrcmp(sender, addr->address) == 0) break;
2561 /*************************************************
2562 * Get valid header address *
2563 *************************************************/
2565 /* Scan the originator headers of the message, looking for an address that
2566 verifies successfully. RFC 822 says:
2568 o The "Sender" field mailbox should be sent notices of
2569 any problems in transport or delivery of the original
2570 messages. If there is no "Sender" field, then the
2571 "From" field mailbox should be used.
2573 o If the "Reply-To" field exists, then the reply should
2574 go to the addresses indicated in that field and not to
2575 the address(es) indicated in the "From" field.
2577 So we check a Sender field if there is one, else a Reply_to field, else a From
2578 field. As some strange messages may have more than one of these fields,
2579 especially if they are resent- fields, check all of them if there is more than
2583 user_msgptr points to where to put a user error message
2584 log_msgptr points to where to put a log error message
2585 callout timeout for callout check (passed to verify_address())
2586 callout_overall overall callout timeout (ditto)
2587 callout_connect connect callout timeout (ditto)
2588 se_mailfrom mailfrom for verify; NULL => ""
2589 pm_mailfrom sender for pm callout check (passed to verify_address())
2590 options callout options (passed to verify_address())
2591 verrno where to put the address basic_errno
2593 If log_msgptr is set to something without setting user_msgptr, the caller
2594 normally uses log_msgptr for both things.
2596 Returns: result of the verification attempt: OK, FAIL, or DEFER;
2597 FAIL is given if no appropriate headers are found
2601 verify_check_header_address(uschar **user_msgptr, uschar **log_msgptr,
2602 int callout, int callout_overall, int callout_connect, uschar *se_mailfrom,
2603 uschar *pm_mailfrom, int options, int *verrno)
2605 static int header_types[] = { htype_sender, htype_reply_to, htype_from };
2610 for (i = 0; i < 3 && !done; i++)
2613 for (h = header_list; h != NULL && !done; h = h->next)
2615 int terminator, new_ok;
2616 uschar *s, *ss, *endname;
2618 if (h->type != header_types[i]) continue;
2619 s = endname = Ustrchr(h->text, ':') + 1;
2621 /* Scan the addresses in the header, enabling group syntax. Note that we
2622 have to reset this after the header has been scanned. */
2624 parse_allow_group = TRUE;
2628 address_item *vaddr;
2630 while (isspace(*s) || *s == ',') s++;
2631 if (*s == 0) break; /* End of header */
2633 ss = parse_find_address_end(s, FALSE);
2635 /* The terminator is a comma or end of header, but there may be white
2636 space preceding it (including newline for the last address). Move back
2637 past any white space so we can check against any cached envelope sender
2638 address verifications. */
2640 while (isspace(ss[-1])) ss--;
2644 HDEBUG(D_verify) debug_printf("verifying %.*s header address %s\n",
2645 (int)(endname - h->text), h->text, s);
2647 /* See if we have already verified this address as an envelope sender,
2648 and if so, use the previous answer. */
2650 vaddr = verify_checked_sender(s);
2652 if (vaddr != NULL && /* Previously checked */
2653 (callout <= 0 || /* No callout needed; OR */
2654 vaddr->special_action > 256)) /* Callout was done */
2656 new_ok = vaddr->special_action & 255;
2657 HDEBUG(D_verify) debug_printf("previously checked as envelope sender\n");
2658 *ss = terminator; /* Restore shortened string */
2661 /* Otherwise we run the verification now. We must restore the shortened
2662 string before running the verification, so the headers are correct, in
2663 case there is any rewriting. */
2667 int start, end, domain;
2668 uschar *address = parse_extract_address(s, log_msgptr, &start, &end,
2673 /* If we found an empty address, just carry on with the next one, but
2674 kill the message. */
2676 if (address == NULL && Ustrcmp(*log_msgptr, "empty address") == 0)
2683 /* If verification failed because of a syntax error, fail this
2684 function, and ensure that the failing address gets added to the error
2687 if (address == NULL)
2690 while (ss > s && isspace(ss[-1])) ss--;
2691 *log_msgptr = string_sprintf("syntax error in '%.*s' header when "
2692 "scanning for sender: %s in \"%.*s\"",
2693 endname - h->text, h->text, *log_msgptr, ss - s, s);
2699 /* Else go ahead with the sender verification. But it isn't *the*
2700 sender of the message, so set vopt_fake_sender to stop sender_address
2701 being replaced after rewriting or qualification. */
2705 vaddr = deliver_make_addr(address, FALSE);
2706 new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender,
2707 callout, callout_overall, callout_connect, se_mailfrom,
2712 /* We now have the result, either newly found, or cached. If we are
2713 giving out error details, set a specific user error. This means that the
2714 last of these will be returned to the user if all three fail. We do not
2715 set a log message - the generic one below will be used. */
2719 *verrno = vaddr->basic_errno;
2720 if (smtp_return_error_details)
2722 *user_msgptr = string_sprintf("Rejected after DATA: "
2723 "could not verify \"%.*s\" header address\n%s: %s",
2724 endname - h->text, h->text, vaddr->address, vaddr->message);
2728 /* Success or defer */
2737 if (new_ok == DEFER) yield = DEFER;
2739 /* Move on to any more addresses in the header */
2742 } /* Next address */
2744 parse_allow_group = FALSE;
2745 parse_found_group = FALSE;
2746 } /* Next header, unless done */
2747 } /* Next header type unless done */
2749 if (yield == FAIL && *log_msgptr == NULL)
2750 *log_msgptr = US"there is no valid sender in any header line";
2752 if (yield == DEFER && *log_msgptr == NULL)
2753 *log_msgptr = US"all attempts to verify a sender in a header line deferred";
2761 /*************************************************
2762 * Get RFC 1413 identification *
2763 *************************************************/
2765 /* Attempt to get an id from the sending machine via the RFC 1413 protocol. If
2766 the timeout is set to zero, then the query is not done. There may also be lists
2767 of hosts and nets which are exempt. To guard against malefactors sending
2768 non-printing characters which could, for example, disrupt a message's headers,
2769 make sure the string consists of printing characters only.
2772 port the port to connect to; usually this is IDENT_PORT (113), but when
2773 running in the test harness with -bh a different value is used.
2777 Side effect: any received ident value is put in sender_ident (NULL otherwise)
2781 verify_get_ident(int port)
2783 int sock, host_af, qlen;
2784 int received_sender_port, received_interface_port, n;
2786 uschar buffer[2048];
2788 /* Default is no ident. Check whether we want to do an ident check for this
2791 sender_ident = NULL;
2792 if (rfc1413_query_timeout <= 0 || verify_check_host(&rfc1413_hosts) != OK)
2795 DEBUG(D_ident) debug_printf("doing ident callback\n");
2797 /* Set up a connection to the ident port of the remote host. Bind the local end
2798 to the incoming interface address. If the sender host address is an IPv6
2799 address, the incoming interface address will also be IPv6. */
2801 host_af = (Ustrchr(sender_host_address, ':') == NULL)? AF_INET : AF_INET6;
2802 sock = ip_socket(SOCK_STREAM, host_af);
2803 if (sock < 0) return;
2805 if (ip_bind(sock, host_af, interface_address, 0) < 0)
2807 DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n",
2812 if (ip_connect(sock, host_af, sender_host_address, port, rfc1413_query_timeout)
2815 if (errno == ETIMEDOUT && (log_extra_selector & LX_ident_timeout) != 0)
2817 log_write(0, LOG_MAIN, "ident connection to %s timed out",
2818 sender_host_address);
2822 DEBUG(D_ident) debug_printf("ident connection to %s failed: %s\n",
2823 sender_host_address, strerror(errno));
2828 /* Construct and send the query. */
2830 sprintf(CS buffer, "%d , %d\r\n", sender_host_port, interface_port);
2831 qlen = Ustrlen(buffer);
2832 if (send(sock, buffer, qlen, 0) < 0)
2834 DEBUG(D_ident) debug_printf("ident send failed: %s\n", strerror(errno));
2838 /* Read a response line. We put it into the rest of the buffer, using several
2839 recv() calls if necessary. */
2847 int size = sizeof(buffer) - (p - buffer);
2849 if (size <= 0) goto END_OFF; /* Buffer filled without seeing \n. */
2850 count = ip_recv(sock, p, size, rfc1413_query_timeout);
2851 if (count <= 0) goto END_OFF; /* Read error or EOF */
2853 /* Scan what we just read, to see if we have reached the terminating \r\n. Be
2854 generous, and accept a plain \n terminator as well. The only illegal
2857 for (pp = p; pp < p + count; pp++)
2859 if (*pp == 0) goto END_OFF; /* Zero octet not allowed */
2862 if (pp[-1] == '\r') pp--;
2864 goto GOT_DATA; /* Break out of both loops */
2868 /* Reached the end of the data without finding \n. Let the loop continue to
2869 read some more, if there is room. */
2876 /* We have received a line of data. Check it carefully. It must start with the
2877 same two port numbers that we sent, followed by data as defined by the RFC. For
2880 12345 , 25 : USERID : UNIX :root
2882 However, the amount of white space may be different to what we sent. In the
2883 "osname" field there may be several sub-fields, comma separated. The data we
2884 actually want to save follows the third colon. Some systems put leading spaces
2885 in it - we discard those. */
2887 if (sscanf(CS buffer + qlen, "%d , %d%n", &received_sender_port,
2888 &received_interface_port, &n) != 2 ||
2889 received_sender_port != sender_host_port ||
2890 received_interface_port != interface_port)
2893 p = buffer + qlen + n;
2894 while(isspace(*p)) p++;
2895 if (*p++ != ':') goto END_OFF;
2896 while(isspace(*p)) p++;
2897 if (Ustrncmp(p, "USERID", 6) != 0) goto END_OFF;
2899 while(isspace(*p)) p++;
2900 if (*p++ != ':') goto END_OFF;
2901 while (*p != 0 && *p != ':') p++;
2902 if (*p++ == 0) goto END_OFF;
2903 while(isspace(*p)) p++;
2904 if (*p == 0) goto END_OFF;
2906 /* The rest of the line is the data we want. We turn it into printing
2907 characters when we save it, so that it cannot mess up the format of any logging
2908 or Received: lines into which it gets inserted. We keep a maximum of 127
2909 characters. The deconst cast is ok as we fed a nonconst to string_printing() */
2911 sender_ident = US string_printing(string_copyn(p, 127));
2912 DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident);
2922 /*************************************************
2923 * Match host to a single host-list item *
2924 *************************************************/
2926 /* This function compares a host (name or address) against a single item
2927 from a host list. The host name gets looked up if it is needed and is not
2928 already known. The function is called from verify_check_this_host() via
2929 match_check_list(), which is why most of its arguments are in a single block.
2932 arg the argument block (see below)
2933 ss the host-list item
2934 valueptr where to pass back looked up data, or NULL
2935 error for error message when returning ERROR
2938 host_name (a) the host name, or
2939 (b) NULL, implying use sender_host_name and
2940 sender_host_aliases, looking them up if required, or
2941 (c) the empty string, meaning that only IP address matches
2943 host_address the host address
2944 host_ipv4 the IPv4 address taken from an IPv6 one
2948 DEFER lookup deferred
2949 ERROR (a) failed to find the host name or IP address, or
2950 (b) unknown lookup type specified, or
2951 (c) host name encountered when only IP addresses are
2956 check_host(void *arg, const uschar *ss, const uschar **valueptr, uschar **error)
2958 check_host_block *cb = (check_host_block *)arg;
2961 BOOL iplookup = FALSE;
2962 BOOL isquery = FALSE;
2963 BOOL isiponly = cb->host_name != NULL && cb->host_name[0] == 0;
2968 /* Optimize for the special case when the pattern is "*". */
2970 if (*ss == '*' && ss[1] == 0) return OK;
2972 /* If the pattern is empty, it matches only in the case when there is no host -
2973 this can occur in ACL checking for SMTP input using the -bs option. In this
2974 situation, the host address is the empty string. */
2976 if (cb->host_address[0] == 0) return (*ss == 0)? OK : FAIL;
2977 if (*ss == 0) return FAIL;
2979 /* If the pattern is precisely "@" then match against the primary host name,
2980 provided that host name matching is permitted; if it's "@[]" match against the
2981 local host's IP addresses. */
2987 if (isiponly) return ERROR;
2988 ss = primary_hostname;
2990 else if (Ustrcmp(ss, "@[]") == 0)
2992 ip_address_item *ip;
2993 for (ip = host_find_interfaces(); ip != NULL; ip = ip->next)
2994 if (Ustrcmp(ip->address, cb->host_address) == 0) return OK;
2999 /* If the pattern is an IP address, optionally followed by a bitmask count, do
3000 a (possibly masked) comparision with the current IP address. */
3002 if (string_is_ip_address(ss, &maskoffset) != 0)
3003 return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL);
3005 /* The pattern is not an IP address. A common error that people make is to omit
3006 one component of an IPv4 address, either by accident, or believing that, for
3007 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,
3008 which it isn't. (Those applications that do accept 1.2.3 as an IP address
3009 interpret it as 1.2.0.3 because the final component becomes 16-bit - this is an
3010 ancient specification.) To aid in debugging these cases, we give a specific
3011 error if the pattern contains only digits and dots or contains a slash preceded
3012 only by digits and dots (a slash at the start indicates a file name and of
3013 course slashes may be present in lookups, but not preceded only by digits and
3016 for (t = ss; isdigit(*t) || *t == '.'; t++);
3017 if (*t == 0 || (*t == '/' && t != ss))
3019 *error = US"malformed IPv4 address or address mask";
3023 /* See if there is a semicolon in the pattern */
3025 semicolon = Ustrchr(ss, ';');
3027 /* If we are doing an IP address only match, then all lookups must be IP
3028 address lookups, even if there is no "net-". */
3032 iplookup = semicolon != NULL;
3035 /* Otherwise, if the item is of the form net[n]-lookup;<file|query> then it is
3036 a lookup on a masked IP network, in textual form. We obey this code even if we
3037 have already set iplookup, so as to skip over the "net-" prefix and to set the
3038 mask length. The net- stuff really only applies to single-key lookups where the
3039 key is implicit. For query-style lookups the key is specified in the query.
3040 From release 4.30, the use of net- for query style is no longer needed, but we
3041 retain it for backward compatibility. */
3043 if (Ustrncmp(ss, "net", 3) == 0 && semicolon != NULL)
3046 for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0';
3047 if (mlen == 0 && t == ss+3) mlen = -1; /* No mask supplied */
3048 iplookup = (*t++ == '-');
3052 /* Do the IP address lookup if that is indeed what we have */
3060 uschar *filename, *key, *result;
3063 /* Find the search type */
3065 search_type = search_findtype(t, semicolon - t);
3067 if (search_type < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
3068 search_error_message);
3070 /* Adjust parameters for the type of lookup. For a query-style lookup, there
3071 is no file name, and the "key" is just the query. For query-style with a file
3072 name, we have to fish the file off the start of the query. For a single-key
3073 lookup, the key is the current IP address, masked appropriately, and
3074 reconverted to text form, with the mask appended. For IPv6 addresses, specify
3075 dot separators instead of colons, except when the lookup type is "iplsearch".
3078 if (mac_islookup(search_type, lookup_absfilequery))
3080 filename = semicolon + 1;
3082 while (*key != 0 && !isspace(*key)) key++;
3083 filename = string_copyn(filename, key - filename);
3084 while (isspace(*key)) key++;
3086 else if (mac_islookup(search_type, lookup_querystyle))
3089 key = semicolon + 1;
3091 else /* Single-key style */
3093 int sep = (Ustrcmp(lookup_list[search_type]->name, "iplsearch") == 0)?
3095 insize = host_aton(cb->host_address, incoming);
3096 host_mask(insize, incoming, mlen);
3097 (void)host_nmtoa(insize, incoming, mlen, buffer, sep);
3099 filename = semicolon + 1;
3102 /* Now do the actual lookup; note that there is no search_close() because
3103 of the caching arrangements. */
3105 handle = search_open(filename, search_type, 0, NULL, NULL);
3106 if (handle == NULL) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
3107 search_error_message);
3108 result = search_find(handle, filename, key, -1, NULL, 0, 0, NULL);
3109 if (valueptr != NULL) *valueptr = result;
3110 return (result != NULL)? OK : search_find_defer? DEFER: FAIL;
3113 /* The pattern is not an IP address or network reference of any kind. That is,
3114 it is a host name pattern. If this is an IP only match, there's an error in the
3119 *error = US"cannot match host name in match_ip list";
3123 /* Check the characters of the pattern to see if they comprise only letters,
3124 digits, full stops, and hyphens (the constituents of domain names). Allow
3125 underscores, as they are all too commonly found. Sigh. Also, if
3126 allow_utf8_domains is set, allow top-bit characters. */
3128 for (t = ss; *t != 0; t++)
3129 if (!isalnum(*t) && *t != '.' && *t != '-' && *t != '_' &&
3130 (!allow_utf8_domains || *t < 128)) break;
3132 /* If the pattern is a complete domain name, with no fancy characters, look up
3133 its IP address and match against that. Note that a multi-homed host will add
3134 items to the chain. */
3145 rc = host_find_byname(&h, NULL, HOST_FIND_QUALIFY_SINGLE, NULL, FALSE);
3146 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3149 for (hh = &h; hh != NULL; hh = hh->next)
3151 if (host_is_in_net(hh->address, cb->host_address, 0)) return OK;
3155 if (rc == HOST_FIND_AGAIN) return DEFER;
3156 *error = string_sprintf("failed to find IP address for %s", ss);
3160 /* Almost all subsequent comparisons require the host name, and can be done
3161 using the general string matching function. When this function is called for
3162 outgoing hosts, the name is always given explicitly. If it is NULL, it means we
3163 must use sender_host_name and its aliases, looking them up if necessary. */
3165 if (cb->host_name != NULL) /* Explicit host name given */
3166 return match_check_string(cb->host_name, ss, -1, TRUE, TRUE, TRUE,
3169 /* Host name not given; in principle we need the sender host name and its
3170 aliases. However, for query-style lookups, we do not need the name if the
3171 query does not contain $sender_host_name. From release 4.23, a reference to
3172 $sender_host_name causes it to be looked up, so we don't need to do the lookup
3175 if ((semicolon = Ustrchr(ss, ';')) != NULL)
3177 const uschar *affix;
3178 int partial, affixlen, starflags, id;
3181 id = search_findtype_partial(ss, &partial, &affix, &affixlen, &starflags);
3184 if (id < 0) /* Unknown lookup type */
3186 log_write(0, LOG_MAIN|LOG_PANIC, "%s in host list item \"%s\"",
3187 search_error_message, ss);
3190 isquery = mac_islookup(id, lookup_querystyle|lookup_absfilequery);
3195 switch(match_check_string(US"", ss, -1, TRUE, TRUE, TRUE, valueptr))
3198 case DEFER: return DEFER;
3199 default: return FAIL;
3203 /* Not a query-style lookup; must ensure the host name is present, and then we
3204 do a check on the name and all its aliases. */
3206 if (sender_host_name == NULL)
3208 HDEBUG(D_host_lookup)
3209 debug_printf("sender host name required, to match against %s\n", ss);
3210 if (host_lookup_failed || host_name_lookup() != OK)
3212 *error = string_sprintf("failed to find host name for %s",
3213 sender_host_address);;
3216 host_build_sender_fullhost();
3219 /* Match on the sender host name, using the general matching function */
3221 switch(match_check_string(sender_host_name, ss, -1, TRUE, TRUE, TRUE,
3225 case DEFER: return DEFER;
3228 /* If there are aliases, try matching on them. */
3230 aliases = sender_host_aliases;
3231 while (*aliases != NULL)
3233 switch(match_check_string(*aliases++, ss, -1, TRUE, TRUE, TRUE, valueptr))
3236 case DEFER: return DEFER;
3245 /*************************************************
3246 * Check a specific host matches a host list *
3247 *************************************************/
3249 /* This function is passed a host list containing items in a number of
3250 different formats and the identity of a host. Its job is to determine whether
3251 the given host is in the set of hosts defined by the list. The host name is
3252 passed as a pointer so that it can be looked up if needed and not already
3253 known. This is commonly the case when called from verify_check_host() to check
3254 an incoming connection. When called from elsewhere the host name should usually
3257 This function is now just a front end to match_check_list(), which runs common
3258 code for scanning a list. We pass it the check_host() function to perform a
3262 listptr pointer to the host list
3263 cache_bits pointer to cache for named lists, or NULL
3264 host_name the host name or NULL, implying use sender_host_name and
3265 sender_host_aliases, looking them up if required
3266 host_address the IP address
3267 valueptr if not NULL, data from a lookup is passed back here
3269 Returns: OK if the host is in the defined set
3270 FAIL if the host is not in the defined set,
3271 DEFER if a data lookup deferred (not a host lookup)
3273 If the host name was needed in order to make a comparison, and could not be
3274 determined from the IP address, the result is FAIL unless the item
3275 "+allow_unknown" was met earlier in the list, in which case OK is returned. */
3278 verify_check_this_host(const uschar **listptr, unsigned int *cache_bits,
3279 const uschar *host_name, const uschar *host_address, const uschar **valueptr)
3282 unsigned int *local_cache_bits = cache_bits;
3283 const uschar *save_host_address = deliver_host_address;
3284 check_host_block cb;
3285 cb.host_name = host_name;
3286 cb.host_address = host_address;
3288 if (valueptr != NULL) *valueptr = NULL;
3290 /* If the host address starts off ::ffff: it is an IPv6 address in
3291 IPv4-compatible mode. Find the IPv4 part for checking against IPv4
3294 cb.host_ipv4 = (Ustrncmp(host_address, "::ffff:", 7) == 0)?
3295 host_address + 7 : host_address;
3297 /* During the running of the check, put the IP address into $host_address. In
3298 the case of calls from the smtp transport, it will already be there. However,
3299 in other calls (e.g. when testing ignore_target_hosts), it won't. Just to be on
3300 the safe side, any existing setting is preserved, though as I write this
3301 (November 2004) I can't see any cases where it is actually needed. */
3303 deliver_host_address = host_address;
3304 rc = match_check_list(
3305 listptr, /* the list */
3306 0, /* separator character */
3307 &hostlist_anchor, /* anchor pointer */
3308 &local_cache_bits, /* cache pointer */
3309 check_host, /* function for testing */
3310 &cb, /* argument for function */
3311 MCL_HOST, /* type of check */
3312 (host_address == sender_host_address)?
3313 US"host" : host_address, /* text for debugging */
3314 valueptr); /* where to pass back data */
3315 deliver_host_address = save_host_address;
3322 /*************************************************
3323 * Check the given host item matches a list *
3324 *************************************************/
3326 verify_check_given_host(uschar **listptr, host_item *host)
3328 return verify_check_this_host(CUSS listptr, NULL, host->name, host->address, NULL);
3331 /*************************************************
3332 * Check the remote host matches a list *
3333 *************************************************/
3335 /* This is a front end to verify_check_this_host(), created because checking
3336 the remote host is a common occurrence. With luck, a good compiler will spot
3337 the tail recursion and optimize it. If there's no host address, this is
3338 command-line SMTP input - check against an empty string for the address.
3341 listptr pointer to the host list
3343 Returns: the yield of verify_check_this_host(),
3344 i.e. OK, FAIL, or DEFER
3348 verify_check_host(uschar **listptr)
3350 return verify_check_this_host(CUSS listptr, sender_host_cache, NULL,
3351 (sender_host_address == NULL)? US"" : sender_host_address, NULL);
3358 /*************************************************
3359 * Invert an IP address *
3360 *************************************************/
3362 /* Originally just used for DNS xBL lists, now also used for the
3363 reverse_ip expansion operator.
3366 buffer where to put the answer
3367 address the address to invert
3371 invert_address(uschar *buffer, uschar *address)
3374 uschar *bptr = buffer;
3376 /* If this is an IPv4 address mapped into IPv6 format, adjust the pointer
3377 to the IPv4 part only. */
3379 if (Ustrncmp(address, "::ffff:", 7) == 0) address += 7;
3381 /* Handle IPv4 address: when HAVE_IPV6 is false, the result of host_aton() is
3384 if (host_aton(address, bin) == 1)
3388 for (i = 0; i < 4; i++)
3390 sprintf(CS bptr, "%d.", x & 255);
3391 while (*bptr) bptr++;
3396 /* Handle IPv6 address. Actually, as far as I know, there are no IPv6 addresses
3397 in any DNS black lists, and the format in which they will be looked up is
3398 unknown. This is just a guess. */
3404 for (j = 3; j >= 0; j--)
3407 for (i = 0; i < 8; i++)
3409 sprintf(CS bptr, "%x.", x & 15);
3410 while (*bptr) bptr++;
3417 /* Remove trailing period -- this is needed so that both arbitrary
3418 dnsbl keydomains and inverted addresses may be combined with the
3419 same format string, "%s.%s" */
3426 /*************************************************
3427 * Perform a single dnsbl lookup *
3428 *************************************************/
3430 /* This function is called from verify_check_dnsbl() below. It is also called
3431 recursively from within itself when domain and domain_txt are different
3432 pointers, in order to get the TXT record from the alternate domain.
3435 domain the outer dnsbl domain
3436 domain_txt alternate domain to lookup TXT record on success; when the
3437 same domain is to be used, domain_txt == domain (that is,
3438 the pointers must be identical, not just the text)
3439 keydomain the current keydomain (for debug message)
3440 prepend subdomain to lookup (like keydomain, but
3441 reversed if IP address)
3442 iplist the list of matching IP addresses, or NULL for "any"
3443 bitmask true if bitmask matching is wanted
3444 match_type condition for 'succeed' result
3445 0 => Any RR in iplist (=)
3446 1 => No RR in iplist (!=)
3447 2 => All RRs in iplist (==)
3448 3 => Some RRs not in iplist (!==)
3449 the two bits are defined as MT_NOT and MT_ALL
3450 defer_return what to return for a defer
3452 Returns: OK if lookup succeeded
3457 one_check_dnsbl(uschar *domain, uschar *domain_txt, uschar *keydomain,
3458 uschar *prepend, uschar *iplist, BOOL bitmask, int match_type,
3464 dnsbl_cache_block *cb;
3465 int old_pool = store_pool;
3466 uschar query[256]; /* DNS domain max length */
3468 /* Construct the specific query domainname */
3470 if (!string_format(query, sizeof(query), "%s.%s", prepend, domain))
3472 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
3473 "(ignored): %s...", query);
3477 /* Look for this query in the cache. */
3479 t = tree_search(dnsbl_cache, query);
3481 /* If not cached from a previous lookup, we must do a DNS lookup, and
3482 cache the result in permanent memory. */
3486 store_pool = POOL_PERM;
3488 /* Set up a tree entry to cache the lookup */
3490 t = store_get(sizeof(tree_node) + Ustrlen(query));
3491 Ustrcpy(t->name, query);
3492 t->data.ptr = cb = store_get(sizeof(dnsbl_cache_block));
3493 (void)tree_insertnode(&dnsbl_cache, t);
3495 /* Do the DNS loopup . */
3497 HDEBUG(D_dnsbl) debug_printf("new DNS lookup for %s\n", query);
3498 cb->rc = dns_basic_lookup(&dnsa, query, T_A);
3499 cb->text_set = FALSE;
3503 /* If the lookup succeeded, cache the RHS address. The code allows for
3504 more than one address - this was for complete generality and the possible
3505 use of A6 records. However, A6 records have been reduced to experimental
3506 status (August 2001) and may die out. So they may never get used at all,
3507 let alone in dnsbl records. However, leave the code here, just in case.
3509 Quite apart from one A6 RR generating multiple addresses, there are DNS
3510 lists that return more than one A record, so we must handle multiple
3511 addresses generated in that way as well. */
3513 if (cb->rc == DNS_SUCCEED)
3516 dns_address **addrp = &(cb->rhs);
3517 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
3519 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3521 if (rr->type == T_A)
3523 dns_address *da = dns_address_from_rr(&dnsa, rr);
3527 while (da->next != NULL) da = da->next;
3528 addrp = &(da->next);
3533 /* If we didn't find any A records, change the return code. This can
3534 happen when there is a CNAME record but there are no A records for what
3537 if (cb->rhs == NULL) cb->rc = DNS_NODATA;
3540 store_pool = old_pool;
3543 /* Previous lookup was cached */
3547 HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
3551 /* We now have the result of the DNS lookup, either newly done, or cached
3552 from a previous call. If the lookup succeeded, check against the address
3553 list if there is one. This may be a positive equality list (introduced by
3554 "="), a negative equality list (introduced by "!="), a positive bitmask
3555 list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/
3557 if (cb->rc == DNS_SUCCEED)
3559 dns_address *da = NULL;
3560 uschar *addlist = cb->rhs->address;
3562 /* For A and AAAA records, there may be multiple addresses from multiple
3563 records. For A6 records (currently not expected to be used) there may be
3564 multiple addresses from a single record. */
3566 for (da = cb->rhs->next; da != NULL; da = da->next)
3567 addlist = string_sprintf("%s, %s", addlist, da->address);
3569 HDEBUG(D_dnsbl) debug_printf("DNS lookup for %s succeeded (yielding %s)\n",
3572 /* Address list check; this can be either for equality, or via a bitmask.
3573 In the latter case, all the bits must match. */
3577 for (da = cb->rhs; da != NULL; da = da->next)
3581 const uschar *ptr = iplist;
3584 /* Handle exact matching */
3588 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))) != NULL)
3590 if (Ustrcmp(CS da->address, ip) == 0) break;
3594 /* Handle bitmask matching */
3601 /* At present, all known DNS blocking lists use A records, with
3602 IPv4 addresses on the RHS encoding the information they return. I
3603 wonder if this will linger on as the last vestige of IPv4 when IPv6
3604 is ubiquitous? Anyway, for now we use paranoia code to completely
3605 ignore IPv6 addresses. The default mask is 0, which always matches.
3606 We change this only for IPv4 addresses in the list. */
3608 if (host_aton(da->address, address) == 1) mask = address[0];
3610 /* Scan the returned addresses, skipping any that are IPv6 */
3612 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))) != NULL)
3614 if (host_aton(ip, address) != 1) continue;
3615 if ((address[0] & mask) == address[0]) break;
3621 (a) An IP address in an any ('=') list matched, or
3622 (b) No IP address in an all ('==') list matched
3624 then we're done searching. */
3626 if (((match_type & MT_ALL) != 0) == (res == NULL)) break;
3629 /* If da == NULL, either
3631 (a) No IP address in an any ('=') list matched, or
3632 (b) An IP address in an all ('==') list didn't match
3634 so behave as if the DNSBL lookup had not succeeded, i.e. the host is not on
3637 if ((match_type == MT_NOT || match_type == MT_ALL) != (da == NULL))
3645 res = US"was no match";
3648 res = US"was an exclude match";
3651 res = US"was an IP address that did not match";
3654 res = US"were no IP addresses that did not match";
3657 debug_printf("=> but we are not accepting this block class because\n");
3658 debug_printf("=> there %s for %s%c%s\n",
3660 ((match_type & MT_ALL) == 0)? "" : "=",
3661 bitmask? '&' : '=', iplist);
3667 /* Either there was no IP list, or the record matched, implying that the
3668 domain is on the list. We now want to find a corresponding TXT record. If an
3669 alternate domain is specified for the TXT record, call this function
3670 recursively to look that up; this has the side effect of re-checking that
3671 there is indeed an A record at the alternate domain. */
3673 if (domain_txt != domain)
3674 return one_check_dnsbl(domain_txt, domain_txt, keydomain, prepend, NULL,
3675 FALSE, match_type, defer_return);
3677 /* If there is no alternate domain, look up a TXT record in the main domain
3678 if it has not previously been cached. */
3682 cb->text_set = TRUE;
3683 if (dns_basic_lookup(&dnsa, query, T_TXT) == DNS_SUCCEED)
3686 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
3688 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3689 if (rr->type == T_TXT) break;
3692 int len = (rr->data)[0];
3693 if (len > 511) len = 127;
3694 store_pool = POOL_PERM;
3695 cb->text = string_sprintf("%.*s", len, (const uschar *)(rr->data+1));
3696 store_pool = old_pool;
3701 dnslist_value = addlist;
3702 dnslist_text = cb->text;
3706 /* There was a problem with the DNS lookup */
3708 if (cb->rc != DNS_NOMATCH && cb->rc != DNS_NODATA)
3710 log_write(L_dnslist_defer, LOG_MAIN,
3711 "DNS list lookup defer (probably timeout) for %s: %s", query,
3712 (defer_return == OK)? US"assumed in list" :
3713 (defer_return == FAIL)? US"assumed not in list" :
3714 US"returned DEFER");
3715 return defer_return;
3718 /* No entry was found in the DNS; continue for next domain */
3722 debug_printf("DNS lookup for %s failed\n", query);
3723 debug_printf("=> that means %s is not listed at %s\n",
3733 /*************************************************
3734 * Check host against DNS black lists *
3735 *************************************************/
3737 /* This function runs checks against a list of DNS black lists, until one
3738 matches. Each item on the list can be of the form
3740 domain=ip-address/key
3742 The domain is the right-most domain that is used for the query, for example,
3743 blackholes.mail-abuse.org. If the IP address is present, there is a match only
3744 if the DNS lookup returns a matching IP address. Several addresses may be
3745 given, comma-separated, for example: x.y.z=127.0.0.1,127.0.0.2.
3747 If no key is given, what is looked up in the domain is the inverted IP address
3748 of the current client host. If a key is given, it is used to construct the
3749 domain for the lookup. For example:
3751 dsn.rfc-ignorant.org/$sender_address_domain
3753 After finding a match in the DNS, the domain is placed in $dnslist_domain, and
3754 then we check for a TXT record for an error message, and if found, save its
3755 value in $dnslist_text. We also cache everything in a tree, to optimize
3758 The TXT record is normally looked up in the same domain as the A record, but
3759 when many lists are combined in a single DNS domain, this will not be a very
3760 specific message. It is possible to specify a different domain for looking up
3761 TXT records; this is given before the main domain, comma-separated. For
3764 dnslists = http.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.2 : \
3765 socks.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.3
3767 The caching ensures that only one lookup in dnsbl.sorbs.net is done.
3769 Note: an address for testing RBL is 192.203.178.39
3770 Note: an address for testing DUL is 192.203.178.4
3771 Note: a domain for testing RFCI is example.tld.dsn.rfc-ignorant.org
3774 listptr the domain/address/data list
3776 Returns: OK successful lookup (i.e. the address is on the list), or
3777 lookup deferred after +include_unknown
3778 FAIL name not found, or no data found for the given type, or
3779 lookup deferred after +exclude_unknown (default)
3780 DEFER lookup failure, if +defer_unknown was set
3784 verify_check_dnsbl(const uschar **listptr)
3787 int defer_return = FAIL;
3788 const uschar *list = *listptr;
3791 uschar buffer[1024];
3792 uschar revadd[128]; /* Long enough for IPv6 address */
3794 /* Indicate that the inverted IP address is not yet set up */
3798 /* In case this is the first time the DNS resolver is being used. */
3800 dns_init(FALSE, FALSE, FALSE); /*XXX dnssec? */
3802 /* Loop through all the domains supplied, until something matches */
3804 while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
3807 BOOL bitmask = FALSE;
3814 HDEBUG(D_dnsbl) debug_printf("DNS list check: %s\n", domain);
3816 /* Deal with special values that change the behaviour on defer */
3818 if (domain[0] == '+')
3820 if (strcmpic(domain, US"+include_unknown") == 0) defer_return = OK;
3821 else if (strcmpic(domain, US"+exclude_unknown") == 0) defer_return = FAIL;
3822 else if (strcmpic(domain, US"+defer_unknown") == 0) defer_return = DEFER;
3824 log_write(0, LOG_MAIN|LOG_PANIC, "unknown item in dnslist (ignored): %s",
3829 /* See if there's explicit data to be looked up */
3831 key = Ustrchr(domain, '/');
3832 if (key != NULL) *key++ = 0;
3834 /* See if there's a list of addresses supplied after the domain name. This is
3835 introduced by an = or a & character; if preceded by = we require all matches
3836 and if preceded by ! we invert the result. */
3838 iplist = Ustrchr(domain, '=');
3842 iplist = Ustrchr(domain, '&');
3845 if (iplist != NULL) /* Found either = or & */
3847 if (iplist > domain && iplist[-1] == '!') /* Handle preceding ! */
3849 match_type |= MT_NOT;
3853 *iplist++ = 0; /* Terminate domain, move on */
3855 /* If we found = (bitmask == FALSE), check for == or =& */
3857 if (!bitmask && (*iplist == '=' || *iplist == '&'))
3859 bitmask = *iplist++ == '&';
3860 match_type |= MT_ALL;
3864 /* If there is a comma in the domain, it indicates that a second domain for
3865 looking up TXT records is provided, before the main domain. Otherwise we must
3866 set domain_txt == domain. */
3868 domain_txt = domain;
3869 comma = Ustrchr(domain, ',');
3876 /* Check that what we have left is a sensible domain name. There is no reason
3877 why these domains should in fact use the same syntax as hosts and email
3878 domains, but in practice they seem to. However, there is little point in
3879 actually causing an error here, because that would no doubt hold up incoming
3880 mail. Instead, I'll just log it. */
3882 for (s = domain; *s != 0; s++)
3884 if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_')
3886 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
3887 "strange characters - is this right?", domain);
3892 /* Check the alternate domain if present */
3894 if (domain_txt != domain) for (s = domain_txt; *s != 0; s++)
3896 if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_')
3898 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
3899 "strange characters - is this right?", domain_txt);
3904 /* If there is no key string, construct the query by adding the domain name
3905 onto the inverted host address, and perform a single DNS lookup. */
3909 if (sender_host_address == NULL) return FAIL; /* can never match */
3910 if (revadd[0] == 0) invert_address(revadd, sender_host_address);
3911 rc = one_check_dnsbl(domain, domain_txt, sender_host_address, revadd,
3912 iplist, bitmask, match_type, defer_return);
3915 dnslist_domain = string_copy(domain_txt);
3916 dnslist_matched = string_copy(sender_host_address);
3917 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
3918 sender_host_address, dnslist_domain);
3920 if (rc != FAIL) return rc; /* OK or DEFER */
3923 /* If there is a key string, it can be a list of domains or IP addresses to
3924 be concatenated with the main domain. */
3931 uschar keybuffer[256];
3932 uschar keyrevadd[128];
3934 while ((keydomain = string_nextinlist(CUSS &key, &keysep, keybuffer,
3935 sizeof(keybuffer))) != NULL)
3937 uschar *prepend = keydomain;
3939 if (string_is_ip_address(keydomain, NULL) != 0)
3941 invert_address(keyrevadd, keydomain);
3942 prepend = keyrevadd;
3945 rc = one_check_dnsbl(domain, domain_txt, keydomain, prepend, iplist,
3946 bitmask, match_type, defer_return);
3950 dnslist_domain = string_copy(domain_txt);
3951 dnslist_matched = string_copy(keydomain);
3952 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
3953 keydomain, dnslist_domain);
3957 /* If the lookup deferred, remember this fact. We keep trying the rest
3958 of the list to see if we get a useful result, and if we don't, we return
3959 DEFER at the end. */
3961 if (rc == DEFER) defer = TRUE;
3962 } /* continue with next keystring domain/address */
3964 if (defer) return DEFER;
3966 } /* continue with next dnsdb outer domain */
3973 /* End of verify.c */