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 address_item cutthrough_addr;
18 static smtp_outblock ctblock;
19 uschar ctbuffer[8192];
22 /* Structure for caching DNSBL lookups */
24 typedef struct dnsbl_cache_block {
32 /* Anchor for DNSBL cache */
34 static tree_node *dnsbl_cache = NULL;
37 /* Bits for match_type in one_check_dnsbl() */
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, 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 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) != 0)
194 address_key = string_sprintf("%s/<%s>", addr->address, sender_address);
195 from_address = sender_address;
197 else if ((options & vopt_callout_recippmaster) != 0)
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)
392 random_local_part = expand_string(callout_random_local_part);
393 if (random_local_part == NULL)
394 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand "
395 "callout_random_local_part: %s", expand_string_message);
398 /* Default the connect and overall callout timeouts if not set, and record the
399 time we are starting so that we can enforce it. */
401 if (callout_overall < 0) callout_overall = 4 * callout;
402 if (callout_connect < 0) callout_connect = callout;
403 callout_start_time = time(NULL);
405 /* Before doing a real callout, if this is an SMTP connection, flush the SMTP
406 output because a callout might take some time. When PIPELINING is active and
407 there are many recipients, the total time for doing lots of callouts can add up
408 and cause the client to time out. So in this case we forgo the PIPELINING
411 if (smtp_out != NULL && !disable_callout_flush) mac_smtp_fflush();
413 /* Now make connections to the hosts and do real callouts. The list of hosts
414 is passed in as an argument. */
416 for (host = host_list; host != NULL && !done; host = host->next)
418 smtp_inblock inblock;
419 smtp_outblock outblock;
422 BOOL send_quit = TRUE;
423 uschar *active_hostname = smtp_active_hostname;
427 BOOL suppress_tls = FALSE;
428 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
429 uschar inbuffer[4096];
430 uschar outbuffer[1024];
431 uschar responsebuffer[4096];
433 clearflag(addr, af_verify_pmfail); /* postmaster callout flag */
434 clearflag(addr, af_verify_nsfail); /* null sender callout flag */
436 /* Skip this host if we don't have an IP address for it. */
438 if (host->address == NULL)
440 DEBUG(D_verify) debug_printf("no IP address for host name %s: skipping\n",
445 /* Check the overall callout timeout */
447 if (time(NULL) - callout_start_time >= callout_overall)
449 HDEBUG(D_verify) debug_printf("overall timeout for callout exceeded\n");
453 /* Set IPv4 or IPv6 */
455 host_af = (Ustrchr(host->address, ':') == NULL)? AF_INET:AF_INET6;
457 /* Expand and interpret the interface and port strings. The latter will not
458 be used if there is a host-specific port (e.g. from a manualroute router).
459 This has to be delayed till now, because they may expand differently for
460 different hosts. If there's a failure, log it, but carry on with the
463 deliver_host = host->name;
464 deliver_host_address = host->address;
465 deliver_domain = addr->domain;
467 if (!smtp_get_interface(tf->interface, host_af, addr, NULL, &interface,
469 !smtp_get_port(tf->port, addr, &port, US"callout"))
470 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
473 /* Set HELO string according to the protocol */
474 lmtp= Ustrcmp(tf->protocol, "lmtp") == 0;
475 smtps= Ustrcmp(tf->protocol, "smtps") == 0;
478 HDEBUG(D_verify) debug_printf("interface=%s port=%d\n", interface, port);
480 /* Set up the buffer for reading SMTP response packets. */
482 inblock.buffer = inbuffer;
483 inblock.buffersize = sizeof(inbuffer);
484 inblock.ptr = inbuffer;
485 inblock.ptrend = inbuffer;
487 /* Set up the buffer for holding SMTP commands while pipelining */
489 outblock.buffer = outbuffer;
490 outblock.buffersize = sizeof(outbuffer);
491 outblock.ptr = outbuffer;
492 outblock.cmd_count = 0;
493 outblock.authenticating = FALSE;
495 /* Reset the parameters of a TLS session */
496 tls_out.cipher = tls_out.peerdn = NULL;
498 /* Connect to the host; on failure, just loop for the next one, but we
499 set the error for the last one. Use the callout_connect timeout. */
501 tls_retry_connection:
503 inblock.sock = outblock.sock =
504 smtp_connect(host, host_af, port, interface, callout_connect, TRUE, NULL);
505 /* reconsider DSCP here */
506 if (inblock.sock < 0)
508 addr->message = string_sprintf("could not connect to %s [%s]: %s",
509 host->name, host->address, strerror(errno));
510 deliver_host = deliver_host_address = NULL;
511 deliver_domain = save_deliver_domain;
515 /* Expand the helo_data string to find the host name to use. */
517 if (tf->helo_data != NULL)
519 uschar *s = expand_string(tf->helo_data);
521 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: failed to expand transport's "
522 "helo_data value for callout: %s", addr->address,
523 expand_string_message);
524 else active_hostname = s;
527 deliver_host = deliver_host_address = NULL;
528 deliver_domain = save_deliver_domain;
530 /* Wait for initial response, and send HELO. The smtp_write_command()
531 function leaves its command in big_buffer. This is used in error responses.
532 Initialize it in case the connection is rejected. */
534 Ustrcpy(big_buffer, "initial connection");
536 /* Unless ssl-on-connect, wait for the initial greeting */
540 if (!smtps || (smtps && tls_out.active >= 0))
542 if (!(done= smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), '2', callout)))
543 goto RESPONSE_FAILED;
545 /* Not worth checking greeting line for ESMTP support */
546 if (!(esmtp = verify_check_this_host(&(ob->hosts_avoid_esmtp), NULL,
547 host->name, host->address, NULL) != OK))
549 debug_printf("not sending EHLO (host matches hosts_avoid_esmtp)\n");
554 if (smtps && tls_out.active < 0) /* ssl-on-connect, first pass */
557 ob->tls_tempfail_tryclear = FALSE;
559 else /* all other cases */
564 if (!(done= smtp_write_command(&outblock, FALSE, "%s %s\r\n",
565 !esmtp? "HELO" : lmtp? "LHLO" : "EHLO", active_hostname) >= 0))
567 if (!smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), '2', callout))
569 if (errno != 0 || responsebuffer[0] == 0 || lmtp || !esmtp || tls_out.active >= 0)
572 goto RESPONSE_FAILED;
578 goto esmtp_retry; /* fallback to HELO */
581 /* Set tls_offered if the response to EHLO specifies support for STARTTLS. */
583 if (esmtp && !suppress_tls && tls_out.active < 0)
585 if (regex_STARTTLS == NULL) regex_STARTTLS =
586 regex_must_compile(US"\\n250[\\s\\-]STARTTLS(\\s|\\n|$)", FALSE, TRUE);
588 tls_offered = pcre_exec(regex_STARTTLS, NULL, CS responsebuffer,
589 Ustrlen(responsebuffer), 0, PCRE_EOPT, NULL, 0) >= 0;
596 /* If TLS is available on this connection attempt to
597 start up a TLS session, unless the host is in hosts_avoid_tls. If successful,
598 send another EHLO - the server may give a different answer in secure mode. We
599 use a separate buffer for reading the response to STARTTLS so that if it is
600 negative, the original EHLO data is available for subsequent analysis, should
601 the client not be required to use TLS. If the response is bad, copy the buffer
602 for error analysis. */
606 verify_check_this_host(&(ob->hosts_avoid_tls), NULL, host->name,
607 host->address, NULL) != OK &&
608 verify_check_this_host(&(ob->hosts_verify_avoid_tls), NULL, host->name,
609 host->address, NULL) != OK
612 uschar buffer2[4096];
614 && !(done= smtp_write_command(&outblock, FALSE, "STARTTLS\r\n") >= 0))
617 /* If there is an I/O error, transmission of this message is deferred. If
618 there is a temporary rejection of STARRTLS and tls_tempfail_tryclear is
619 false, we also defer. However, if there is a temporary rejection of STARTTLS
620 and tls_tempfail_tryclear is true, or if there is an outright rejection of
621 STARTTLS, we carry on. This means we will try to send the message in clear,
622 unless the host is in hosts_require_tls (tested below). */
624 if (!smtps && !smtp_read_response(&inblock, buffer2, sizeof(buffer2), '2',
625 ob->command_timeout))
627 if (errno != 0 || buffer2[0] == 0 ||
628 (buffer2[0] == '4' && !ob->tls_tempfail_tryclear))
630 Ustrncpy(responsebuffer, buffer2, sizeof(responsebuffer));
632 goto RESPONSE_FAILED;
636 /* STARTTLS accepted or ssl-on-connect: try to negotiate a TLS session. */
639 int rc = tls_client_start(inblock.sock, host, addr,
640 ob->tls_certificate, ob->tls_privatekey,
642 ob->tls_verify_certificates, ob->tls_crl,
643 ob->tls_require_ciphers,
644 #ifdef EXPERIMENTAL_OCSP
645 ob->hosts_require_ocsp,
647 ob->tls_dh_min_bits, callout,
648 ob->tls_verify_hosts, ob->tls_try_verify_hosts);
650 /* TLS negotiation failed; give an error. Try in clear on a new connection,
651 if the options permit it for this host. */
654 if (rc == DEFER && ob->tls_tempfail_tryclear && !smtps &&
655 verify_check_this_host(&(ob->hosts_require_tls), NULL, host->name,
656 host->address, NULL) != OK)
658 (void)close(inblock.sock);
659 log_write(0, LOG_MAIN, "TLS session failure: delivering unencrypted "
660 "to %s [%s] (not in hosts_require_tls)", host->name, host->address);
662 goto tls_retry_connection;
664 /*save_errno = ERRNO_TLSFAILURE;*/
665 /*message = US"failure while setting up TLS session";*/
671 /* TLS session is set up. Copy info for logging. */
672 addr->cipher = tls_out.cipher;
673 addr->peerdn = tls_out.peerdn;
675 /* For SMTPS we need to wait for the initial OK response, then do HELO. */
677 goto smtps_redo_greeting;
679 /* For STARTTLS we need to redo EHLO */
684 /* If the host is required to use a secure channel, ensure that we have one. */
685 if (tls_out.active < 0)
686 if (verify_check_this_host(&(ob->hosts_require_tls), NULL, host->name,
687 host->address, NULL) == OK)
689 /*save_errno = ERRNO_TLSREQUIRED;*/
690 log_write(0, LOG_MAIN, "a TLS session is required for %s [%s], but %s",
691 host->name, host->address,
692 tls_offered? "an attempt to start TLS failed" : "the server did not offer TLS support");
697 #endif /*SUPPORT_TLS*/
699 done = TRUE; /* so far so good; have response to HELO */
701 /*XXX the EHLO response would be analyzed here for IGNOREQUOTA, SIZE, PIPELINING */
703 /* For now, transport_filter by cutthrough-delivery is not supported */
704 /* Need proper integration with the proper transport mechanism. */
705 if (cutthrough_delivery)
707 if (addr->transport->filter_command)
709 cutthrough_delivery= FALSE;
710 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of transport filter\n");
715 cutthrough_delivery= FALSE;
716 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of DKIM signing\n");
725 /* Clear down of the TLS, SMTP and TCP layers on error is handled below. */
728 /* Failure to accept HELO is cached; this blocks the whole domain for all
729 senders. I/O errors and defer responses are not cached. */
733 *failure_ptr = US"mail"; /* At or before MAIL */
734 if (errno == 0 && responsebuffer[0] == '5')
736 setflag(addr, af_verify_nsfail);
737 new_domain_record.result = ccache_reject;
741 /* If we haven't authenticated, but are required to, give up. */
744 else done = smtp_auth(responsebuffer, sizeof(responsebuffer),
745 addr, host, ob, esmtp, &inblock, &outblock) == OK &&
747 /* Copy AUTH info for logging */
748 ( (addr->authenticator = client_authenticator),
749 (addr->auth_id = client_authenticated_id),
751 /* Build a mail-AUTH string (re-using responsebuffer for convenience */
752 !smtp_mail_auth_str(responsebuffer, sizeof(responsebuffer), addr, ob)
755 ( (addr->auth_sndr = client_authenticated_sender),
757 /* Send the MAIL command */
758 (smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>%s\r\n",
759 from_address, responsebuffer) >= 0)
762 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
765 /* If the host does not accept MAIL FROM:<>, arrange to cache this
766 information, but again, don't record anything for an I/O error or a defer. Do
767 not cache rejections of MAIL when a non-empty sender has been used, because
768 that blocks the whole domain for all senders. */
772 *failure_ptr = US"mail"; /* At or before MAIL */
773 if (errno == 0 && responsebuffer[0] == '5')
775 setflag(addr, af_verify_nsfail);
776 if (from_address[0] == 0)
777 new_domain_record.result = ccache_reject_mfnull;
781 /* Otherwise, proceed to check a "random" address (if required), then the
782 given address, and the postmaster address (if required). Between each check,
783 issue RSET, because some servers accept only one recipient after MAIL
786 Before doing this, set the result in the domain cache record to "accept",
787 unless its previous value was ccache_reject_mfnull. In that case, the domain
788 rejects MAIL FROM:<> and we want to continue to remember that. When that is
789 the case, we have got here only in the case of a recipient verification with
790 a non-null sender. */
794 new_domain_record.result =
795 (old_domain_cache_result == ccache_reject_mfnull)?
796 ccache_reject_mfnull: ccache_accept;
798 /* Do the random local part check first */
800 if (random_local_part != NULL)
802 uschar randombuffer[1024];
804 smtp_write_command(&outblock, FALSE,
805 "RCPT TO:<%.1000s@%.1000s>\r\n", random_local_part,
806 addr->domain) >= 0 &&
807 smtp_read_response(&inblock, randombuffer,
808 sizeof(randombuffer), '2', callout);
810 /* Remember when we last did a random test */
812 new_domain_record.random_stamp = time(NULL);
814 /* If accepted, we aren't going to do any further tests below. */
818 new_domain_record.random_result = ccache_accept;
821 /* Otherwise, cache a real negative response, and get back to the right
822 state to send RCPT. Unless there's some problem such as a dropped
823 connection, we expect to succeed, because the commands succeeded above. */
827 if (randombuffer[0] == '5')
828 new_domain_record.random_result = ccache_reject;
831 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
832 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
835 smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>\r\n",
836 from_address) >= 0 &&
837 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
840 else done = FALSE; /* Some timeout/connection problem */
843 /* If the host is accepting all local parts, as determined by the "random"
844 check, we don't need to waste time doing any further checking. */
846 if (new_domain_record.random_result != ccache_accept && done)
848 /* Get the rcpt_include_affixes flag from the transport if there is one,
849 but assume FALSE if there is not. */
852 smtp_write_command(&outblock, FALSE, "RCPT TO:<%.1000s>\r\n",
853 transport_rcpt_address(addr,
854 (addr->transport == NULL)? FALSE :
855 addr->transport->rcpt_include_affixes)) >= 0 &&
856 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
860 new_address_record.result = ccache_accept;
861 else if (errno == 0 && responsebuffer[0] == '5')
863 *failure_ptr = US"recipient";
864 new_address_record.result = ccache_reject;
867 /* Do postmaster check if requested; if a full check is required, we
868 check for RCPT TO:<postmaster> (no domain) in accordance with RFC 821. */
870 if (done && pm_mailfrom != NULL)
872 /*XXX not suitable for cutthrough - sequencing problems */
873 cutthrough_delivery= FALSE;
874 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of postmaster verify\n");
877 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
878 smtp_read_response(&inblock, responsebuffer,
879 sizeof(responsebuffer), '2', callout) &&
881 smtp_write_command(&outblock, FALSE,
882 "MAIL FROM:<%s>\r\n", pm_mailfrom) >= 0 &&
883 smtp_read_response(&inblock, responsebuffer,
884 sizeof(responsebuffer), '2', callout) &&
886 /* First try using the current domain */
889 smtp_write_command(&outblock, FALSE,
890 "RCPT TO:<postmaster@%.1000s>\r\n", addr->domain) >= 0 &&
891 smtp_read_response(&inblock, responsebuffer,
892 sizeof(responsebuffer), '2', callout)
897 /* If that doesn't work, and a full check is requested,
898 try without the domain. */
901 (options & vopt_callout_fullpm) != 0 &&
902 smtp_write_command(&outblock, FALSE,
903 "RCPT TO:<postmaster>\r\n") >= 0 &&
904 smtp_read_response(&inblock, responsebuffer,
905 sizeof(responsebuffer), '2', callout)
908 /* Sort out the cache record */
910 new_domain_record.postmaster_stamp = time(NULL);
913 new_domain_record.postmaster_result = ccache_accept;
914 else if (errno == 0 && responsebuffer[0] == '5')
916 *failure_ptr = US"postmaster";
917 setflag(addr, af_verify_pmfail);
918 new_domain_record.postmaster_result = ccache_reject;
921 } /* Random not accepted */
922 } /* MAIL FROM: accepted */
924 /* For any failure of the main check, other than a negative response, we just
925 close the connection and carry on. We can identify a negative response by the
926 fact that errno is zero. For I/O errors it will be non-zero
928 Set up different error texts for logging and for sending back to the caller
929 as an SMTP response. Log in all cases, using a one-line format. For sender
930 callouts, give a full response to the caller, but for recipient callouts,
931 don't give the IP address because this may be an internal host whose identity
932 is not to be widely broadcast. */
936 if (errno == ETIMEDOUT)
938 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
943 if (*responsebuffer == 0) Ustrcpy(responsebuffer, US"connection dropped");
946 string_sprintf("response to \"%s\" from %s [%s] was: %s",
947 big_buffer, host->name, host->address,
948 string_printing(responsebuffer));
950 addr->user_message = is_recipient?
951 string_sprintf("Callout verification failed:\n%s", responsebuffer)
953 string_sprintf("Called: %s\nSent: %s\nResponse: %s",
954 host->address, big_buffer, responsebuffer);
956 /* Hard rejection ends the process */
958 if (responsebuffer[0] == '5') /* Address rejected */
966 /* End the SMTP conversation and close the connection. */
968 /* Cutthrough - on a successfull connect and recipient-verify with use-sender
969 and we have no cutthrough conn so far
970 here is where we want to leave the conn open */
971 if ( cutthrough_delivery
974 && (options & (vopt_callout_recipsender|vopt_callout_recippmaster)) == vopt_callout_recipsender
975 && !random_local_part
980 cutthrough_fd= outblock.sock; /* We assume no buffer in use in the outblock */
981 cutthrough_addr = *addr; /* Save the address_item for later logging */
982 cutthrough_addr.next = NULL;
983 cutthrough_addr.host_used = store_get(sizeof(host_item));
984 cutthrough_addr.host_used->name = host->name;
985 cutthrough_addr.host_used->address = host->address;
986 cutthrough_addr.host_used->port = port;
988 *(cutthrough_addr.parent = store_get(sizeof(address_item)))= *addr->parent;
989 ctblock.buffer = ctbuffer;
990 ctblock.buffersize = sizeof(ctbuffer);
991 ctblock.ptr = ctbuffer;
992 /* ctblock.cmd_count = 0; ctblock.authenticating = FALSE; */
993 ctblock.sock = cutthrough_fd;
997 /* Ensure no cutthrough on multiple address verifies */
998 if (options & vopt_callout_recipsender)
999 cancel_cutthrough_connection("multiple verify calls");
1000 if (send_quit) (void)smtp_write_command(&outblock, FALSE, "QUIT\r\n");
1003 tls_close(FALSE, TRUE);
1005 (void)close(inblock.sock);
1008 } /* Loop through all hosts, while !done */
1011 /* If we get here with done == TRUE, a successful callout happened, and yield
1012 will be set OK or FAIL according to the response to the RCPT command.
1013 Otherwise, we looped through the hosts but couldn't complete the business.
1014 However, there may be domain-specific information to cache in both cases.
1016 The value of the result field in the new_domain record is ccache_unknown if
1017 there was an error before or with MAIL FROM:, and errno was not zero,
1018 implying some kind of I/O error. We don't want to write the cache in that case.
1019 Otherwise the value is ccache_accept, ccache_reject, or ccache_reject_mfnull. */
1021 if (!callout_no_cache && new_domain_record.result != ccache_unknown)
1023 if ((dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE))
1026 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
1030 (void)dbfn_write(dbm_file, addr->domain, &new_domain_record,
1031 (int)sizeof(dbdata_callout_cache));
1032 HDEBUG(D_verify) debug_printf("wrote callout cache domain record:\n"
1033 " result=%d postmaster=%d random=%d\n",
1034 new_domain_record.result,
1035 new_domain_record.postmaster_result,
1036 new_domain_record.random_result);
1040 /* If a definite result was obtained for the callout, cache it unless caching
1045 if (!callout_no_cache && new_address_record.result != ccache_unknown)
1047 if (dbm_file == NULL)
1048 dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE);
1049 if (dbm_file == NULL)
1051 HDEBUG(D_verify) debug_printf("no callout cache available\n");
1055 (void)dbfn_write(dbm_file, address_key, &new_address_record,
1056 (int)sizeof(dbdata_callout_cache_address));
1057 HDEBUG(D_verify) debug_printf("wrote %s callout cache address record\n",
1058 (new_address_record.result == ccache_accept)? "positive" : "negative");
1063 /* Failure to connect to any host, or any response other than 2xx or 5xx is a
1064 temporary error. If there was only one host, and a response was received, leave
1065 it alone if supplying details. Otherwise, give a generic response. */
1069 uschar *dullmsg = string_sprintf("Could not complete %s verify callout",
1070 is_recipient? "recipient" : "sender");
1073 if (host_list->next != NULL || addr->message == NULL) addr->message = dullmsg;
1075 addr->user_message = (!smtp_return_error_details)? dullmsg :
1076 string_sprintf("%s for <%s>.\n"
1077 "The mail server(s) for the domain may be temporarily unreachable, or\n"
1078 "they may be permanently unreachable from this server. In the latter case,\n%s",
1079 dullmsg, addr->address,
1081 "the address will never be accepted."
1083 "you need to change the address or create an MX record for its domain\n"
1084 "if it is supposed to be generally accessible from the Internet.\n"
1085 "Talk to your mail administrator for details.");
1087 /* Force a specific error code */
1089 addr->basic_errno = ERRNO_CALLOUTDEFER;
1092 /* Come here from within the cache-reading code on fast-track exit. */
1095 if (dbm_file != NULL) dbfn_close(dbm_file);
1101 /* Called after recipient-acl to get a cutthrough connection open when
1102 one was requested and a recipient-verify wasn't subsequently done.
1105 open_cutthrough_connection( address_item * addr )
1109 /* Use a recipient-verify-callout to set up the cutthrough connection. */
1110 /* We must use a copy of the address for verification, because it might
1114 HDEBUG(D_acl) debug_printf("----------- start cutthrough setup ------------\n");
1115 (void) verify_address(&addr2, NULL,
1116 vopt_is_recipient | vopt_callout_recipsender | vopt_callout_no_cache,
1117 CUTTHROUGH_CMD_TIMEOUT, -1, -1,
1119 HDEBUG(D_acl) debug_printf("----------- end cutthrough setup ------------\n");
1125 /* Send given number of bytes from the buffer */
1127 cutthrough_send(int n)
1129 if(cutthrough_fd < 0)
1134 (tls_out.active == cutthrough_fd) ? tls_write(FALSE, ctblock.buffer, n) :
1136 send(cutthrough_fd, ctblock.buffer, n, 0) > 0
1139 transport_count += n;
1140 ctblock.ptr= ctblock.buffer;
1144 HDEBUG(D_transport|D_acl) debug_printf("cutthrough_send failed: %s\n", strerror(errno));
1151 _cutthrough_puts(uschar * cp, int n)
1155 if(ctblock.ptr >= ctblock.buffer+ctblock.buffersize)
1156 if(!cutthrough_send(ctblock.buffersize))
1159 *ctblock.ptr++ = *cp++;
1164 /* Buffered output of counted data block. Return boolean success */
1166 cutthrough_puts(uschar * cp, int n)
1168 if (cutthrough_fd < 0) return TRUE;
1169 if (_cutthrough_puts(cp, n)) return TRUE;
1170 cancel_cutthrough_connection("transmit failed");
1176 _cutthrough_flush_send( void )
1178 int n= ctblock.ptr-ctblock.buffer;
1181 if(!cutthrough_send(n))
1187 /* Send out any bufferred output. Return boolean success. */
1189 cutthrough_flush_send( void )
1191 if (_cutthrough_flush_send()) return TRUE;
1192 cancel_cutthrough_connection("transmit failed");
1198 cutthrough_put_nl( void )
1200 return cutthrough_puts(US"\r\n", 2);
1204 /* Get and check response from cutthrough target */
1206 cutthrough_response(char expect, uschar ** copy)
1208 smtp_inblock inblock;
1209 uschar inbuffer[4096];
1210 uschar responsebuffer[4096];
1212 inblock.buffer = inbuffer;
1213 inblock.buffersize = sizeof(inbuffer);
1214 inblock.ptr = inbuffer;
1215 inblock.ptrend = inbuffer;
1216 inblock.sock = cutthrough_fd;
1217 /* this relies on (inblock.sock == tls_out.active) */
1218 if(!smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), expect, CUTTHROUGH_DATA_TIMEOUT))
1219 cancel_cutthrough_connection("target timeout on read");
1224 *copy= cp= string_copy(responsebuffer);
1225 /* Trim the trailing end of line */
1226 cp += Ustrlen(responsebuffer);
1227 if(cp > *copy && cp[-1] == '\n') *--cp = '\0';
1228 if(cp > *copy && cp[-1] == '\r') *--cp = '\0';
1231 return responsebuffer[0];
1235 /* Negotiate dataphase with the cutthrough target, returning success boolean */
1237 cutthrough_predata( void )
1239 if(cutthrough_fd < 0)
1242 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> DATA\n");
1243 cutthrough_puts(US"DATA\r\n", 6);
1244 cutthrough_flush_send();
1246 /* Assume nothing buffered. If it was it gets ignored. */
1247 return cutthrough_response('3', NULL) == '3';
1251 /* fd and use_crlf args only to match write_chunk() */
1253 cutthrough_write_chunk(int fd, uschar * s, int len, BOOL use_crlf)
1256 while(s && (s2 = Ustrchr(s, '\n')))
1258 if(!cutthrough_puts(s, s2-s) || !cutthrough_put_nl())
1266 /* Buffered send of headers. Return success boolean. */
1267 /* Expands newlines to wire format (CR,NL). */
1268 /* Also sends header-terminating blank line. */
1270 cutthrough_headers_send( void )
1272 if(cutthrough_fd < 0)
1275 /* We share a routine with the mainline transport to handle header add/remove/rewrites,
1276 but having a separate buffered-output function (for now)
1278 HDEBUG(D_acl) debug_printf("----------- start cutthrough headers send -----------\n");
1280 if (!transport_headers_send(&cutthrough_addr, cutthrough_fd,
1281 cutthrough_addr.transport->add_headers, cutthrough_addr.transport->remove_headers,
1282 &cutthrough_write_chunk, TRUE,
1283 cutthrough_addr.transport->rewrite_rules, cutthrough_addr.transport->rewrite_existflags))
1286 HDEBUG(D_acl) debug_printf("----------- done cutthrough headers send ------------\n");
1292 close_cutthrough_connection( const char * why )
1294 if(cutthrough_fd >= 0)
1296 /* We could be sending this after a bunch of data, but that is ok as
1297 the only way to cancel the transfer in dataphase is to drop the tcp
1298 conn before the final dot.
1300 ctblock.ptr = ctbuffer;
1301 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> QUIT\n");
1302 _cutthrough_puts(US"QUIT\r\n", 6); /* avoid recursion */
1303 _cutthrough_flush_send();
1304 /* No wait for response */
1307 tls_close(FALSE, TRUE);
1309 (void)close(cutthrough_fd);
1311 HDEBUG(D_acl) debug_printf("----------- cutthrough shutdown (%s) ------------\n", why);
1313 ctblock.ptr = ctbuffer;
1317 cancel_cutthrough_connection( const char * why )
1319 close_cutthrough_connection(why);
1320 cutthrough_delivery= FALSE;
1326 /* Have senders final-dot. Send one to cutthrough target, and grab the response.
1327 Log an OK response as a transmission.
1328 Close the connection.
1329 Return smtp response-class digit.
1332 cutthrough_finaldot( void )
1334 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> .\n");
1336 /* Assume data finshed with new-line */
1337 if(!cutthrough_puts(US".", 1) || !cutthrough_put_nl() || !cutthrough_flush_send())
1338 return cutthrough_addr.message;
1340 switch(cutthrough_response('2', &cutthrough_addr.message))
1343 delivery_log(LOG_MAIN, &cutthrough_addr, (int)'>', NULL);
1344 close_cutthrough_connection("delivered");
1348 delivery_log(LOG_MAIN, &cutthrough_addr, 0, US"tmp-reject from cutthrough after DATA:");
1352 delivery_log(LOG_MAIN|LOG_REJECT, &cutthrough_addr, 0, US"rejected after DATA:");
1358 return cutthrough_addr.message;
1363 /*************************************************
1364 * Copy error to toplevel address *
1365 *************************************************/
1367 /* This function is used when a verify fails or defers, to ensure that the
1368 failure or defer information is in the original toplevel address. This applies
1369 when an address is redirected to a single new address, and the failure or
1370 deferral happens to the child address.
1373 vaddr the verify address item
1374 addr the final address item
1377 Returns: the value of YIELD
1381 copy_error(address_item *vaddr, address_item *addr, int yield)
1385 vaddr->message = addr->message;
1386 vaddr->user_message = addr->user_message;
1387 vaddr->basic_errno = addr->basic_errno;
1388 vaddr->more_errno = addr->more_errno;
1389 vaddr->p.address_data = addr->p.address_data;
1390 copyflag(vaddr, addr, af_pass_message);
1398 /**************************************************
1399 * printf that automatically handles TLS if needed *
1400 ***************************************************/
1402 /* This function is used by verify_address() as a substitute for all fprintf()
1403 calls; a direct fprintf() will not produce output in a TLS SMTP session, such
1404 as a response to an EXPN command. smtp_in.c makes smtp_printf available but
1405 that assumes that we always use the smtp_out FILE* when not using TLS or the
1406 ssl buffer when we are. Instead we take a FILE* parameter and check to see if
1407 that is smtp_out; if so, smtp_printf() with TLS support, otherwise regular
1411 f the candidate FILE* to write to
1412 format format string
1413 ... optional arguments
1419 static void PRINTF_FUNCTION(2,3)
1420 respond_printf(FILE *f, const char *format, ...)
1424 va_start(ap, format);
1425 if (smtp_out && (f == smtp_out))
1426 smtp_vprintf(format, ap);
1428 vfprintf(f, format, ap);
1434 /*************************************************
1435 * Verify an email address *
1436 *************************************************/
1438 /* This function is used both for verification (-bv and at other times) and
1439 address testing (-bt), which is indicated by address_test_mode being set.
1442 vaddr contains the address to verify; the next field in this block
1444 f if not NULL, write the result to this file
1445 options various option bits:
1446 vopt_fake_sender => this sender verify is not for the real
1447 sender (it was verify=sender=xxxx or an address from a
1448 header line) - rewriting must not change sender_address
1449 vopt_is_recipient => this is a recipient address, otherwise
1450 it's a sender address - this affects qualification and
1451 rewriting and messages from callouts
1452 vopt_qualify => qualify an unqualified address; else error
1453 vopt_expn => called from SMTP EXPN command
1454 vopt_success_on_redirect => when a new address is generated
1455 the verification instantly succeeds
1457 These ones are used by do_callout() -- the options variable
1460 vopt_callout_fullpm => if postmaster check, do full one
1461 vopt_callout_no_cache => don't use callout cache
1462 vopt_callout_random => do the "random" thing
1463 vopt_callout_recipsender => use real sender for recipient
1464 vopt_callout_recippmaster => use postmaster for recipient
1466 callout if > 0, specifies that callout is required, and gives timeout
1467 for individual commands
1468 callout_overall if > 0, gives overall timeout for the callout function;
1469 if < 0, a default is used (see do_callout())
1470 callout_connect the connection timeout for callouts
1471 se_mailfrom when callout is requested to verify a sender, use this
1472 in MAIL FROM; NULL => ""
1473 pm_mailfrom when callout is requested, if non-NULL, do the postmaster
1474 thing and use this as the sender address (may be "")
1476 routed if not NULL, set TRUE if routing succeeded, so we can
1477 distinguish between routing failed and callout failed
1479 Returns: OK address verified
1480 FAIL address failed to verify
1481 DEFER can't tell at present
1485 verify_address(address_item *vaddr, FILE *f, int options, int callout,
1486 int callout_overall, int callout_connect, uschar *se_mailfrom,
1487 uschar *pm_mailfrom, BOOL *routed)
1490 BOOL full_info = (f == NULL)? FALSE : (debug_selector != 0);
1491 BOOL is_recipient = (options & vopt_is_recipient) != 0;
1492 BOOL expn = (options & vopt_expn) != 0;
1493 BOOL success_on_redirect = (options & vopt_success_on_redirect) != 0;
1496 int verify_type = expn? v_expn :
1497 address_test_mode? v_none :
1498 is_recipient? v_recipient : v_sender;
1499 address_item *addr_list;
1500 address_item *addr_new = NULL;
1501 address_item *addr_remote = NULL;
1502 address_item *addr_local = NULL;
1503 address_item *addr_succeed = NULL;
1504 uschar **failure_ptr = is_recipient?
1505 &recipient_verify_failure : &sender_verify_failure;
1506 uschar *ko_prefix, *cr;
1507 uschar *address = vaddr->address;
1508 uschar *save_sender;
1509 uschar null_sender[] = { 0 }; /* Ensure writeable memory */
1511 /* Clear, just in case */
1513 *failure_ptr = NULL;
1515 /* Set up a prefix and suffix for error message which allow us to use the same
1516 output statements both in EXPN mode (where an SMTP response is needed) and when
1517 debugging with an output file. */
1521 ko_prefix = US"553 ";
1524 else ko_prefix = cr = US"";
1526 /* Add qualify domain if permitted; otherwise an unqualified address fails. */
1528 if (parse_find_at(address) == NULL)
1530 if ((options & vopt_qualify) == 0)
1533 respond_printf(f, "%sA domain is required for \"%s\"%s\n",
1534 ko_prefix, address, cr);
1535 *failure_ptr = US"qualify";
1538 address = rewrite_address_qualify(address, is_recipient);
1543 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1544 debug_printf("%s %s\n", address_test_mode? "Testing" : "Verifying", address);
1547 /* Rewrite and report on it. Clear the domain and local part caches - these
1548 may have been set by domains and local part tests during an ACL. */
1550 if (global_rewrite_rules != NULL)
1552 uschar *old = address;
1553 address = rewrite_address(address, is_recipient, FALSE,
1554 global_rewrite_rules, rewrite_existflags);
1557 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->localpart_cache[i] = 0;
1558 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->domain_cache[i] = 0;
1559 if (f != NULL && !expn) fprintf(f, "Address rewritten as: %s\n", address);
1563 /* If this is the real sender address, we must update sender_address at
1564 this point, because it may be referred to in the routers. */
1566 if ((options & (vopt_fake_sender|vopt_is_recipient)) == 0)
1567 sender_address = address;
1569 /* If the address was rewritten to <> no verification can be done, and we have
1570 to return OK. This rewriting is permitted only for sender addresses; for other
1571 addresses, such rewriting fails. */
1573 if (address[0] == 0) return OK;
1575 /* Flip the legacy TLS-related variables over to the outbound set in case
1576 they're used in the context of a transport used by verification. Reset them
1577 at exit from this routine. */
1579 tls_modify_variables(&tls_out);
1581 /* Save a copy of the sender address for re-instating if we change it to <>
1582 while verifying a sender address (a nice bit of self-reference there). */
1584 save_sender = sender_address;
1586 /* Update the address structure with the possibly qualified and rewritten
1587 address. Set it up as the starting address on the chain of new addresses. */
1589 vaddr->address = address;
1592 /* We need a loop, because an address can generate new addresses. We must also
1593 cope with generated pipes and files at the top level. (See also the code and
1594 comment in deliver.c.) However, it is usually the case that the router for
1595 user's .forward files has its verify flag turned off.
1597 If an address generates more than one child, the loop is used only when
1598 full_info is set, and this can only be set locally. Remote enquiries just get
1599 information about the top level address, not anything that it generated. */
1601 while (addr_new != NULL)
1604 address_item *addr = addr_new;
1606 addr_new = addr->next;
1611 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1612 debug_printf("Considering %s\n", addr->address);
1615 /* Handle generated pipe, file or reply addresses. We don't get these
1616 when handling EXPN, as it does only one level of expansion. */
1618 if (testflag(addr, af_pfr))
1625 if (addr->address[0] == '>')
1627 allow = testflag(addr, af_allow_reply);
1628 fprintf(f, "%s -> mail %s", addr->parent->address, addr->address + 1);
1632 allow = (addr->address[0] == '|')?
1633 testflag(addr, af_allow_pipe) : testflag(addr, af_allow_file);
1634 fprintf(f, "%s -> %s", addr->parent->address, addr->address);
1637 if (addr->basic_errno == ERRNO_BADTRANSPORT)
1638 fprintf(f, "\n*** Error in setting up pipe, file, or autoreply:\n"
1639 "%s\n", addr->message);
1641 fprintf(f, "\n transport = %s\n", addr->transport->name);
1643 fprintf(f, " *** forbidden ***\n");
1648 /* Just in case some router parameter refers to it. */
1650 return_path = (addr->p.errors_address != NULL)?
1651 addr->p.errors_address : sender_address;
1653 /* Split the address into domain and local part, handling the %-hack if
1654 necessary, and then route it. While routing a sender address, set
1655 $sender_address to <> because that is what it will be if we were trying to
1656 send a bounce to the sender. */
1658 if (routed != NULL) *routed = FALSE;
1659 if ((rc = deliver_split_address(addr)) == OK)
1661 if (!is_recipient) sender_address = null_sender;
1662 rc = route_address(addr, &addr_local, &addr_remote, &addr_new,
1663 &addr_succeed, verify_type);
1664 sender_address = save_sender; /* Put back the real sender */
1667 /* If routing an address succeeded, set the flag that remembers, for use when
1668 an ACL cached a sender verify (in case a callout fails). Then if routing set
1669 up a list of hosts or the transport has a host list, and the callout option
1670 is set, and we aren't in a host checking run, do the callout verification,
1671 and set another flag that notes that a callout happened. */
1675 if (routed != NULL) *routed = TRUE;
1678 host_item *host_list = addr->host_list;
1680 /* Make up some data for use in the case where there is no remote
1683 transport_feedback tf = {
1684 NULL, /* interface (=> any) */
1685 US"smtp", /* port */
1686 US"smtp", /* protocol */
1688 US"$smtp_active_hostname", /* helo_data */
1689 FALSE, /* hosts_override */
1690 FALSE, /* hosts_randomize */
1691 FALSE, /* gethostbyname */
1692 TRUE, /* qualify_single */
1693 FALSE /* search_parents */
1696 /* If verification yielded a remote transport, we want to use that
1697 transport's options, so as to mimic what would happen if we were really
1698 sending a message to this address. */
1700 if (addr->transport != NULL && !addr->transport->info->local)
1702 (void)(addr->transport->setup)(addr->transport, addr, &tf, 0, 0, NULL);
1704 /* If the transport has hosts and the router does not, or if the
1705 transport is configured to override the router's hosts, we must build a
1706 host list of the transport's hosts, and find the IP addresses */
1708 if (tf.hosts != NULL && (host_list == NULL || tf.hosts_override))
1711 uschar *save_deliver_domain = deliver_domain;
1712 uschar *save_deliver_localpart = deliver_localpart;
1714 host_list = NULL; /* Ignore the router's hosts */
1716 deliver_domain = addr->domain;
1717 deliver_localpart = addr->local_part;
1718 s = expand_string(tf.hosts);
1719 deliver_domain = save_deliver_domain;
1720 deliver_localpart = save_deliver_localpart;
1724 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand list of hosts "
1725 "\"%s\" in %s transport for callout: %s", tf.hosts,
1726 addr->transport->name, expand_string_message);
1731 uschar *canonical_name;
1732 host_item *host, *nexthost;
1733 host_build_hostlist(&host_list, s, tf.hosts_randomize);
1735 /* Just ignore failures to find a host address. If we don't manage
1736 to find any addresses, the callout will defer. Note that more than
1737 one address may be found for a single host, which will result in
1738 additional host items being inserted into the chain. Hence we must
1739 save the next host first. */
1741 flags = HOST_FIND_BY_A;
1742 if (tf.qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
1743 if (tf.search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
1745 for (host = host_list; host != NULL; host = nexthost)
1747 nexthost = host->next;
1748 if (tf.gethostbyname ||
1749 string_is_ip_address(host->name, NULL) != 0)
1750 (void)host_find_byname(host, NULL, flags, &canonical_name, TRUE);
1752 (void)host_find_bydns(host, NULL, flags, NULL, NULL, NULL,
1753 NULL, NULL, /*XXX todo: dnssec */
1754 &canonical_name, NULL);
1760 /* Can only do a callout if we have at least one host! If the callout
1761 fails, it will have set ${sender,recipient}_verify_failure. */
1763 if (host_list != NULL)
1765 HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n");
1766 if (host_checking && !host_checking_callout)
1769 debug_printf("... callout omitted by default when host testing\n"
1770 "(Use -bhc if you want the callouts to happen.)\n");
1775 deliver_set_expansions(addr);
1777 rc = do_callout(addr, host_list, &tf, callout, callout_overall,
1778 callout_connect, options, se_mailfrom, pm_mailfrom);
1783 HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor "
1784 "transport provided a host list\n");
1789 /* Otherwise, any failure is a routing failure */
1791 else *failure_ptr = US"route";
1793 /* A router may return REROUTED if it has set up a child address as a result
1794 of a change of domain name (typically from widening). In this case we always
1795 want to continue to verify the new child. */
1797 if (rc == REROUTED) continue;
1799 /* Handle hard failures */
1806 address_item *p = addr->parent;
1808 respond_printf(f, "%s%s %s", ko_prefix,
1809 full_info? addr->address : address,
1810 address_test_mode? "is undeliverable" : "failed to verify");
1811 if (!expn && admin_user)
1813 if (addr->basic_errno > 0)
1814 respond_printf(f, ": %s", strerror(addr->basic_errno));
1815 if (addr->message != NULL)
1816 respond_printf(f, ": %s", addr->message);
1819 /* Show parents iff doing full info */
1821 if (full_info) while (p != NULL)
1823 respond_printf(f, "%s\n <-- %s", cr, p->address);
1826 respond_printf(f, "%s\n", cr);
1828 cancel_cutthrough_connection("routing hard fail");
1832 yield = copy_error(vaddr, addr, FAIL);
1840 else if (rc == DEFER)
1845 address_item *p = addr->parent;
1846 respond_printf(f, "%s%s cannot be resolved at this time", ko_prefix,
1847 full_info? addr->address : address);
1848 if (!expn && admin_user)
1850 if (addr->basic_errno > 0)
1851 respond_printf(f, ": %s", strerror(addr->basic_errno));
1852 if (addr->message != NULL)
1853 respond_printf(f, ": %s", addr->message);
1854 else if (addr->basic_errno <= 0)
1855 respond_printf(f, ": unknown error");
1858 /* Show parents iff doing full info */
1860 if (full_info) while (p != NULL)
1862 respond_printf(f, "%s\n <-- %s", cr, p->address);
1865 respond_printf(f, "%s\n", cr);
1867 cancel_cutthrough_connection("routing soft fail");
1871 yield = copy_error(vaddr, addr, DEFER);
1874 else if (yield == OK) yield = DEFER;
1877 /* If we are handling EXPN, we do not want to continue to route beyond
1878 the top level (whose address is in "address"). */
1882 uschar *ok_prefix = US"250-";
1883 if (addr_new == NULL)
1885 if (addr_local == NULL && addr_remote == NULL)
1886 respond_printf(f, "250 mail to <%s> is discarded\r\n", address);
1888 respond_printf(f, "250 <%s>\r\n", address);
1890 else while (addr_new != NULL)
1892 address_item *addr2 = addr_new;
1893 addr_new = addr2->next;
1894 if (addr_new == NULL) ok_prefix = US"250 ";
1895 respond_printf(f, "%s<%s>\r\n", ok_prefix, addr2->address);
1901 /* Successful routing other than EXPN. */
1905 /* Handle successful routing when short info wanted. Otherwise continue for
1906 other (generated) addresses. Short info is the operational case. Full info
1907 can be requested only when debug_selector != 0 and a file is supplied.
1909 There is a conflict between the use of aliasing as an alternate email
1910 address, and as a sort of mailing list. If an alias turns the incoming
1911 address into just one address (e.g. J.Caesar->jc44) you may well want to
1912 carry on verifying the generated address to ensure it is valid when
1913 checking incoming mail. If aliasing generates multiple addresses, you
1914 probably don't want to do this. Exim therefore treats the generation of
1915 just a single new address as a special case, and continues on to verify the
1916 generated address. */
1918 if (!full_info && /* Stop if short info wanted AND */
1919 (((addr_new == NULL || /* No new address OR */
1920 addr_new->next != NULL || /* More than one new address OR */
1921 testflag(addr_new, af_pfr))) /* New address is pfr */
1923 (addr_new != NULL && /* At least one new address AND */
1924 success_on_redirect))) /* success_on_redirect is set */
1926 if (f != NULL) fprintf(f, "%s %s\n", address,
1927 address_test_mode? "is deliverable" : "verified");
1929 /* If we have carried on to verify a child address, we want the value
1930 of $address_data to be that of the child */
1932 vaddr->p.address_data = addr->p.address_data;
1937 } /* Loop for generated addresses */
1939 /* Display the full results of the successful routing, including any generated
1940 addresses. Control gets here only when full_info is set, which requires f not
1941 to be NULL, and this occurs only when a top-level verify is called with the
1942 debugging switch on.
1944 If there are no local and no remote addresses, and there were no pipes, files,
1945 or autoreplies, and there were no errors or deferments, the message is to be
1946 discarded, usually because of the use of :blackhole: in an alias file. */
1948 if (allok && addr_local == NULL && addr_remote == NULL)
1950 fprintf(f, "mail to %s is discarded\n", address);
1954 for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++)
1956 while (addr_list != NULL)
1958 address_item *addr = addr_list;
1959 address_item *p = addr->parent;
1960 addr_list = addr->next;
1962 fprintf(f, "%s", CS addr->address);
1963 #ifdef EXPERIMENTAL_SRS
1964 if(addr->p.srs_sender)
1965 fprintf(f, " [srs = %s]", addr->p.srs_sender);
1968 /* If the address is a duplicate, show something about it. */
1970 if (!testflag(addr, af_pfr))
1973 if ((tnode = tree_search(tree_duplicates, addr->unique)) != NULL)
1974 fprintf(f, " [duplicate, would not be delivered]");
1975 else tree_add_duplicate(addr->unique, addr);
1978 /* Now show its parents */
1982 fprintf(f, "\n <-- %s", p->address);
1987 /* Show router, and transport */
1989 fprintf(f, "router = %s, ", addr->router->name);
1990 fprintf(f, "transport = %s\n", (addr->transport == NULL)? US"unset" :
1991 addr->transport->name);
1993 /* Show any hosts that are set up by a router unless the transport
1994 is going to override them; fiddle a bit to get a nice format. */
1996 if (addr->host_list != NULL && addr->transport != NULL &&
1997 !addr->transport->overrides_hosts)
2002 for (h = addr->host_list; h != NULL; h = h->next)
2004 int len = Ustrlen(h->name);
2005 if (len > maxlen) maxlen = len;
2006 len = (h->address != NULL)? Ustrlen(h->address) : 7;
2007 if (len > maxaddlen) maxaddlen = len;
2009 for (h = addr->host_list; h != NULL; h = h->next)
2011 int len = Ustrlen(h->name);
2012 fprintf(f, " host %s ", h->name);
2013 while (len++ < maxlen) fprintf(f, " ");
2014 if (h->address != NULL)
2016 fprintf(f, "[%s] ", h->address);
2017 len = Ustrlen(h->address);
2019 else if (!addr->transport->info->local) /* Omit [unknown] for local */
2021 fprintf(f, "[unknown] ");
2025 while (len++ < maxaddlen) fprintf(f," ");
2026 if (h->mx >= 0) fprintf(f, "MX=%d", h->mx);
2027 if (h->port != PORT_NONE) fprintf(f, " port=%d", h->port);
2028 if (h->status == hstatus_unusable) fprintf(f, " ** unusable **");
2035 /* Yield will be DEFER or FAIL if any one address has, only for full_info (which is
2036 the -bv or -bt case). */
2039 tls_modify_variables(&tls_in);
2047 /*************************************************
2048 * Check headers for syntax errors *
2049 *************************************************/
2051 /* This function checks those header lines that contain addresses, and verifies
2052 that all the addresses therein are syntactially correct.
2055 msgptr where to put an error message
2062 verify_check_headers(uschar **msgptr)
2068 for (h = header_list; h != NULL && yield == OK; h = h->next)
2070 if (h->type != htype_from &&
2071 h->type != htype_reply_to &&
2072 h->type != htype_sender &&
2073 h->type != htype_to &&
2074 h->type != htype_cc &&
2075 h->type != htype_bcc)
2078 colon = Ustrchr(h->text, ':');
2080 while (isspace(*s)) s++;
2082 /* Loop for multiple addresses in the header, enabling group syntax. Note
2083 that we have to reset this after the header has been scanned. */
2085 parse_allow_group = TRUE;
2089 uschar *ss = parse_find_address_end(s, FALSE);
2090 uschar *recipient, *errmess;
2091 int terminator = *ss;
2092 int start, end, domain;
2094 /* Temporarily terminate the string at this point, and extract the
2095 operative address within, allowing group syntax. */
2098 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2101 /* Permit an unqualified address only if the message is local, or if the
2102 sending host is configured to be permitted to send them. */
2104 if (recipient != NULL && domain == 0)
2106 if (h->type == htype_from || h->type == htype_sender)
2108 if (!allow_unqualified_sender) recipient = NULL;
2112 if (!allow_unqualified_recipient) recipient = NULL;
2114 if (recipient == NULL) errmess = US"unqualified address not permitted";
2117 /* It's an error if no address could be extracted, except for the special
2118 case of an empty address. */
2120 if (recipient == NULL && Ustrcmp(errmess, "empty address") != 0)
2122 uschar *verb = US"is";
2127 /* Arrange not to include any white space at the end in the
2128 error message or the header name. */
2130 while (t > s && isspace(t[-1])) t--;
2131 while (tt > h->text && isspace(tt[-1])) tt--;
2133 /* Add the address that failed to the error message, since in a
2134 header with very many addresses it is sometimes hard to spot
2135 which one is at fault. However, limit the amount of address to
2136 quote - cases have been seen where, for example, a missing double
2137 quote in a humungous To: header creates an "address" that is longer
2138 than string_sprintf can handle. */
2147 *msgptr = string_printing(
2148 string_sprintf("%s: failing address in \"%.*s:\" header %s: %.*s",
2149 errmess, tt - h->text, h->text, verb, len, s));
2152 break; /* Out of address loop */
2155 /* Advance to the next address */
2157 s = ss + (terminator? 1:0);
2158 while (isspace(*s)) s++;
2159 } /* Next address */
2161 parse_allow_group = FALSE;
2162 parse_found_group = FALSE;
2163 } /* Next header unless yield has been set FALSE */
2169 /*************************************************
2170 * Check header names for 8-bit characters *
2171 *************************************************/
2173 /* This function checks for invalid charcters in header names. See
2174 RFC 5322, 2.2. and RFC 6532, 3.
2177 msgptr where to put an error message
2184 verify_check_header_names_ascii(uschar **msgptr)
2189 for (h = header_list; h != NULL; h = h->next)
2191 colon = Ustrchr(h->text, ':');
2192 for(s = h->text; s < colon; s++)
2194 if ((*s < 33) || (*s > 126))
2196 *msgptr = string_sprintf("Invalid character in header \"%.*s\" found",
2197 colon - h->text, h->text);
2205 /*************************************************
2206 * Check for blind recipients *
2207 *************************************************/
2209 /* This function checks that every (envelope) recipient is mentioned in either
2210 the To: or Cc: header lines, thus detecting blind carbon copies.
2212 There are two ways of scanning that could be used: either scan the header lines
2213 and tick off the recipients, or scan the recipients and check the header lines.
2214 The original proposed patch did the former, but I have chosen to do the latter,
2215 because (a) it requires no memory and (b) will use fewer resources when there
2216 are many addresses in To: and/or Cc: and only one or two envelope recipients.
2219 Returns: OK if there are no blind recipients
2220 FAIL if there is at least one blind recipient
2224 verify_check_notblind(void)
2227 for (i = 0; i < recipients_count; i++)
2231 uschar *address = recipients_list[i].address;
2233 for (h = header_list; !found && h != NULL; h = h->next)
2237 if (h->type != htype_to && h->type != htype_cc) continue;
2239 colon = Ustrchr(h->text, ':');
2241 while (isspace(*s)) s++;
2243 /* Loop for multiple addresses in the header, enabling group syntax. Note
2244 that we have to reset this after the header has been scanned. */
2246 parse_allow_group = TRUE;
2250 uschar *ss = parse_find_address_end(s, FALSE);
2251 uschar *recipient,*errmess;
2252 int terminator = *ss;
2253 int start, end, domain;
2255 /* Temporarily terminate the string at this point, and extract the
2256 operative address within, allowing group syntax. */
2259 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2262 /* If we found a valid recipient that has a domain, compare it with the
2263 envelope recipient. Local parts are compared case-sensitively, domains
2264 case-insensitively. By comparing from the start with length "domain", we
2265 include the "@" at the end, which ensures that we are comparing the whole
2266 local part of each address. */
2268 if (recipient != NULL && domain != 0)
2270 found = Ustrncmp(recipient, address, domain) == 0 &&
2271 strcmpic(recipient + domain, address + domain) == 0;
2275 /* Advance to the next address */
2277 s = ss + (terminator? 1:0);
2278 while (isspace(*s)) s++;
2279 } /* Next address */
2281 parse_allow_group = FALSE;
2282 parse_found_group = FALSE;
2283 } /* Next header (if found is false) */
2285 if (!found) return FAIL;
2286 } /* Next recipient */
2293 /*************************************************
2294 * Find if verified sender *
2295 *************************************************/
2297 /* Usually, just a single address is verified as the sender of the message.
2298 However, Exim can be made to verify other addresses as well (often related in
2299 some way), and this is useful in some environments. There may therefore be a
2300 chain of such addresses that have previously been tested. This function finds
2301 whether a given address is on the chain.
2303 Arguments: the address to be verified
2304 Returns: pointer to an address item, or NULL
2308 verify_checked_sender(uschar *sender)
2311 for (addr = sender_verified_list; addr != NULL; addr = addr->next)
2312 if (Ustrcmp(sender, addr->address) == 0) break;
2320 /*************************************************
2321 * Get valid header address *
2322 *************************************************/
2324 /* Scan the originator headers of the message, looking for an address that
2325 verifies successfully. RFC 822 says:
2327 o The "Sender" field mailbox should be sent notices of
2328 any problems in transport or delivery of the original
2329 messages. If there is no "Sender" field, then the
2330 "From" field mailbox should be used.
2332 o If the "Reply-To" field exists, then the reply should
2333 go to the addresses indicated in that field and not to
2334 the address(es) indicated in the "From" field.
2336 So we check a Sender field if there is one, else a Reply_to field, else a From
2337 field. As some strange messages may have more than one of these fields,
2338 especially if they are resent- fields, check all of them if there is more than
2342 user_msgptr points to where to put a user error message
2343 log_msgptr points to where to put a log error message
2344 callout timeout for callout check (passed to verify_address())
2345 callout_overall overall callout timeout (ditto)
2346 callout_connect connect callout timeout (ditto)
2347 se_mailfrom mailfrom for verify; NULL => ""
2348 pm_mailfrom sender for pm callout check (passed to verify_address())
2349 options callout options (passed to verify_address())
2350 verrno where to put the address basic_errno
2352 If log_msgptr is set to something without setting user_msgptr, the caller
2353 normally uses log_msgptr for both things.
2355 Returns: result of the verification attempt: OK, FAIL, or DEFER;
2356 FAIL is given if no appropriate headers are found
2360 verify_check_header_address(uschar **user_msgptr, uschar **log_msgptr,
2361 int callout, int callout_overall, int callout_connect, uschar *se_mailfrom,
2362 uschar *pm_mailfrom, int options, int *verrno)
2364 static int header_types[] = { htype_sender, htype_reply_to, htype_from };
2369 for (i = 0; i < 3 && !done; i++)
2372 for (h = header_list; h != NULL && !done; h = h->next)
2374 int terminator, new_ok;
2375 uschar *s, *ss, *endname;
2377 if (h->type != header_types[i]) continue;
2378 s = endname = Ustrchr(h->text, ':') + 1;
2380 /* Scan the addresses in the header, enabling group syntax. Note that we
2381 have to reset this after the header has been scanned. */
2383 parse_allow_group = TRUE;
2387 address_item *vaddr;
2389 while (isspace(*s) || *s == ',') s++;
2390 if (*s == 0) break; /* End of header */
2392 ss = parse_find_address_end(s, FALSE);
2394 /* The terminator is a comma or end of header, but there may be white
2395 space preceding it (including newline for the last address). Move back
2396 past any white space so we can check against any cached envelope sender
2397 address verifications. */
2399 while (isspace(ss[-1])) ss--;
2403 HDEBUG(D_verify) debug_printf("verifying %.*s header address %s\n",
2404 (int)(endname - h->text), h->text, s);
2406 /* See if we have already verified this address as an envelope sender,
2407 and if so, use the previous answer. */
2409 vaddr = verify_checked_sender(s);
2411 if (vaddr != NULL && /* Previously checked */
2412 (callout <= 0 || /* No callout needed; OR */
2413 vaddr->special_action > 256)) /* Callout was done */
2415 new_ok = vaddr->special_action & 255;
2416 HDEBUG(D_verify) debug_printf("previously checked as envelope sender\n");
2417 *ss = terminator; /* Restore shortened string */
2420 /* Otherwise we run the verification now. We must restore the shortened
2421 string before running the verification, so the headers are correct, in
2422 case there is any rewriting. */
2426 int start, end, domain;
2427 uschar *address = parse_extract_address(s, log_msgptr, &start, &end,
2432 /* If we found an empty address, just carry on with the next one, but
2433 kill the message. */
2435 if (address == NULL && Ustrcmp(*log_msgptr, "empty address") == 0)
2442 /* If verification failed because of a syntax error, fail this
2443 function, and ensure that the failing address gets added to the error
2446 if (address == NULL)
2449 while (ss > s && isspace(ss[-1])) ss--;
2450 *log_msgptr = string_sprintf("syntax error in '%.*s' header when "
2451 "scanning for sender: %s in \"%.*s\"",
2452 endname - h->text, h->text, *log_msgptr, ss - s, s);
2458 /* Else go ahead with the sender verification. But it isn't *the*
2459 sender of the message, so set vopt_fake_sender to stop sender_address
2460 being replaced after rewriting or qualification. */
2464 vaddr = deliver_make_addr(address, FALSE);
2465 new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender,
2466 callout, callout_overall, callout_connect, se_mailfrom,
2471 /* We now have the result, either newly found, or cached. If we are
2472 giving out error details, set a specific user error. This means that the
2473 last of these will be returned to the user if all three fail. We do not
2474 set a log message - the generic one below will be used. */
2478 *verrno = vaddr->basic_errno;
2479 if (smtp_return_error_details)
2481 *user_msgptr = string_sprintf("Rejected after DATA: "
2482 "could not verify \"%.*s\" header address\n%s: %s",
2483 endname - h->text, h->text, vaddr->address, vaddr->message);
2487 /* Success or defer */
2496 if (new_ok == DEFER) yield = DEFER;
2498 /* Move on to any more addresses in the header */
2501 } /* Next address */
2503 parse_allow_group = FALSE;
2504 parse_found_group = FALSE;
2505 } /* Next header, unless done */
2506 } /* Next header type unless done */
2508 if (yield == FAIL && *log_msgptr == NULL)
2509 *log_msgptr = US"there is no valid sender in any header line";
2511 if (yield == DEFER && *log_msgptr == NULL)
2512 *log_msgptr = US"all attempts to verify a sender in a header line deferred";
2520 /*************************************************
2521 * Get RFC 1413 identification *
2522 *************************************************/
2524 /* Attempt to get an id from the sending machine via the RFC 1413 protocol. If
2525 the timeout is set to zero, then the query is not done. There may also be lists
2526 of hosts and nets which are exempt. To guard against malefactors sending
2527 non-printing characters which could, for example, disrupt a message's headers,
2528 make sure the string consists of printing characters only.
2531 port the port to connect to; usually this is IDENT_PORT (113), but when
2532 running in the test harness with -bh a different value is used.
2536 Side effect: any received ident value is put in sender_ident (NULL otherwise)
2540 verify_get_ident(int port)
2542 int sock, host_af, qlen;
2543 int received_sender_port, received_interface_port, n;
2545 uschar buffer[2048];
2547 /* Default is no ident. Check whether we want to do an ident check for this
2550 sender_ident = NULL;
2551 if (rfc1413_query_timeout <= 0 || verify_check_host(&rfc1413_hosts) != OK)
2554 DEBUG(D_ident) debug_printf("doing ident callback\n");
2556 /* Set up a connection to the ident port of the remote host. Bind the local end
2557 to the incoming interface address. If the sender host address is an IPv6
2558 address, the incoming interface address will also be IPv6. */
2560 host_af = (Ustrchr(sender_host_address, ':') == NULL)? AF_INET : AF_INET6;
2561 sock = ip_socket(SOCK_STREAM, host_af);
2562 if (sock < 0) return;
2564 if (ip_bind(sock, host_af, interface_address, 0) < 0)
2566 DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n",
2571 if (ip_connect(sock, host_af, sender_host_address, port, rfc1413_query_timeout)
2574 if (errno == ETIMEDOUT && (log_extra_selector & LX_ident_timeout) != 0)
2576 log_write(0, LOG_MAIN, "ident connection to %s timed out",
2577 sender_host_address);
2581 DEBUG(D_ident) debug_printf("ident connection to %s failed: %s\n",
2582 sender_host_address, strerror(errno));
2587 /* Construct and send the query. */
2589 sprintf(CS buffer, "%d , %d\r\n", sender_host_port, interface_port);
2590 qlen = Ustrlen(buffer);
2591 if (send(sock, buffer, qlen, 0) < 0)
2593 DEBUG(D_ident) debug_printf("ident send failed: %s\n", strerror(errno));
2597 /* Read a response line. We put it into the rest of the buffer, using several
2598 recv() calls if necessary. */
2606 int size = sizeof(buffer) - (p - buffer);
2608 if (size <= 0) goto END_OFF; /* Buffer filled without seeing \n. */
2609 count = ip_recv(sock, p, size, rfc1413_query_timeout);
2610 if (count <= 0) goto END_OFF; /* Read error or EOF */
2612 /* Scan what we just read, to see if we have reached the terminating \r\n. Be
2613 generous, and accept a plain \n terminator as well. The only illegal
2616 for (pp = p; pp < p + count; pp++)
2618 if (*pp == 0) goto END_OFF; /* Zero octet not allowed */
2621 if (pp[-1] == '\r') pp--;
2623 goto GOT_DATA; /* Break out of both loops */
2627 /* Reached the end of the data without finding \n. Let the loop continue to
2628 read some more, if there is room. */
2635 /* We have received a line of data. Check it carefully. It must start with the
2636 same two port numbers that we sent, followed by data as defined by the RFC. For
2639 12345 , 25 : USERID : UNIX :root
2641 However, the amount of white space may be different to what we sent. In the
2642 "osname" field there may be several sub-fields, comma separated. The data we
2643 actually want to save follows the third colon. Some systems put leading spaces
2644 in it - we discard those. */
2646 if (sscanf(CS buffer + qlen, "%d , %d%n", &received_sender_port,
2647 &received_interface_port, &n) != 2 ||
2648 received_sender_port != sender_host_port ||
2649 received_interface_port != interface_port)
2652 p = buffer + qlen + n;
2653 while(isspace(*p)) p++;
2654 if (*p++ != ':') goto END_OFF;
2655 while(isspace(*p)) p++;
2656 if (Ustrncmp(p, "USERID", 6) != 0) goto END_OFF;
2658 while(isspace(*p)) p++;
2659 if (*p++ != ':') goto END_OFF;
2660 while (*p != 0 && *p != ':') p++;
2661 if (*p++ == 0) goto END_OFF;
2662 while(isspace(*p)) p++;
2663 if (*p == 0) goto END_OFF;
2665 /* The rest of the line is the data we want. We turn it into printing
2666 characters when we save it, so that it cannot mess up the format of any logging
2667 or Received: lines into which it gets inserted. We keep a maximum of 127
2670 sender_ident = string_printing(string_copyn(p, 127));
2671 DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident);
2681 /*************************************************
2682 * Match host to a single host-list item *
2683 *************************************************/
2685 /* This function compares a host (name or address) against a single item
2686 from a host list. The host name gets looked up if it is needed and is not
2687 already known. The function is called from verify_check_this_host() via
2688 match_check_list(), which is why most of its arguments are in a single block.
2691 arg the argument block (see below)
2692 ss the host-list item
2693 valueptr where to pass back looked up data, or NULL
2694 error for error message when returning ERROR
2697 host_name (a) the host name, or
2698 (b) NULL, implying use sender_host_name and
2699 sender_host_aliases, looking them up if required, or
2700 (c) the empty string, meaning that only IP address matches
2702 host_address the host address
2703 host_ipv4 the IPv4 address taken from an IPv6 one
2707 DEFER lookup deferred
2708 ERROR (a) failed to find the host name or IP address, or
2709 (b) unknown lookup type specified, or
2710 (c) host name encountered when only IP addresses are
2715 check_host(void *arg, uschar *ss, uschar **valueptr, uschar **error)
2717 check_host_block *cb = (check_host_block *)arg;
2720 BOOL iplookup = FALSE;
2721 BOOL isquery = FALSE;
2722 BOOL isiponly = cb->host_name != NULL && cb->host_name[0] == 0;
2727 /* Optimize for the special case when the pattern is "*". */
2729 if (*ss == '*' && ss[1] == 0) return OK;
2731 /* If the pattern is empty, it matches only in the case when there is no host -
2732 this can occur in ACL checking for SMTP input using the -bs option. In this
2733 situation, the host address is the empty string. */
2735 if (cb->host_address[0] == 0) return (*ss == 0)? OK : FAIL;
2736 if (*ss == 0) return FAIL;
2738 /* If the pattern is precisely "@" then match against the primary host name,
2739 provided that host name matching is permitted; if it's "@[]" match against the
2740 local host's IP addresses. */
2746 if (isiponly) return ERROR;
2747 ss = primary_hostname;
2749 else if (Ustrcmp(ss, "@[]") == 0)
2751 ip_address_item *ip;
2752 for (ip = host_find_interfaces(); ip != NULL; ip = ip->next)
2753 if (Ustrcmp(ip->address, cb->host_address) == 0) return OK;
2758 /* If the pattern is an IP address, optionally followed by a bitmask count, do
2759 a (possibly masked) comparision with the current IP address. */
2761 if (string_is_ip_address(ss, &maskoffset) != 0)
2762 return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL);
2764 /* The pattern is not an IP address. A common error that people make is to omit
2765 one component of an IPv4 address, either by accident, or believing that, for
2766 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,
2767 which it isn't. (Those applications that do accept 1.2.3 as an IP address
2768 interpret it as 1.2.0.3 because the final component becomes 16-bit - this is an
2769 ancient specification.) To aid in debugging these cases, we give a specific
2770 error if the pattern contains only digits and dots or contains a slash preceded
2771 only by digits and dots (a slash at the start indicates a file name and of
2772 course slashes may be present in lookups, but not preceded only by digits and
2775 for (t = ss; isdigit(*t) || *t == '.'; t++);
2776 if (*t == 0 || (*t == '/' && t != ss))
2778 *error = US"malformed IPv4 address or address mask";
2782 /* See if there is a semicolon in the pattern */
2784 semicolon = Ustrchr(ss, ';');
2786 /* If we are doing an IP address only match, then all lookups must be IP
2787 address lookups, even if there is no "net-". */
2791 iplookup = semicolon != NULL;
2794 /* Otherwise, if the item is of the form net[n]-lookup;<file|query> then it is
2795 a lookup on a masked IP network, in textual form. We obey this code even if we
2796 have already set iplookup, so as to skip over the "net-" prefix and to set the
2797 mask length. The net- stuff really only applies to single-key lookups where the
2798 key is implicit. For query-style lookups the key is specified in the query.
2799 From release 4.30, the use of net- for query style is no longer needed, but we
2800 retain it for backward compatibility. */
2802 if (Ustrncmp(ss, "net", 3) == 0 && semicolon != NULL)
2805 for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0';
2806 if (mlen == 0 && t == ss+3) mlen = -1; /* No mask supplied */
2807 iplookup = (*t++ == '-');
2811 /* Do the IP address lookup if that is indeed what we have */
2819 uschar *filename, *key, *result;
2822 /* Find the search type */
2824 search_type = search_findtype(t, semicolon - t);
2826 if (search_type < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
2827 search_error_message);
2829 /* Adjust parameters for the type of lookup. For a query-style lookup, there
2830 is no file name, and the "key" is just the query. For query-style with a file
2831 name, we have to fish the file off the start of the query. For a single-key
2832 lookup, the key is the current IP address, masked appropriately, and
2833 reconverted to text form, with the mask appended. For IPv6 addresses, specify
2834 dot separators instead of colons, except when the lookup type is "iplsearch".
2837 if (mac_islookup(search_type, lookup_absfilequery))
2839 filename = semicolon + 1;
2841 while (*key != 0 && !isspace(*key)) key++;
2842 filename = string_copyn(filename, key - filename);
2843 while (isspace(*key)) key++;
2845 else if (mac_islookup(search_type, lookup_querystyle))
2848 key = semicolon + 1;
2850 else /* Single-key style */
2852 int sep = (Ustrcmp(lookup_list[search_type]->name, "iplsearch") == 0)?
2854 insize = host_aton(cb->host_address, incoming);
2855 host_mask(insize, incoming, mlen);
2856 (void)host_nmtoa(insize, incoming, mlen, buffer, sep);
2858 filename = semicolon + 1;
2861 /* Now do the actual lookup; note that there is no search_close() because
2862 of the caching arrangements. */
2864 handle = search_open(filename, search_type, 0, NULL, NULL);
2865 if (handle == NULL) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
2866 search_error_message);
2867 result = search_find(handle, filename, key, -1, NULL, 0, 0, NULL);
2868 if (valueptr != NULL) *valueptr = result;
2869 return (result != NULL)? OK : search_find_defer? DEFER: FAIL;
2872 /* The pattern is not an IP address or network reference of any kind. That is,
2873 it is a host name pattern. If this is an IP only match, there's an error in the
2878 *error = US"cannot match host name in match_ip list";
2882 /* Check the characters of the pattern to see if they comprise only letters,
2883 digits, full stops, and hyphens (the constituents of domain names). Allow
2884 underscores, as they are all too commonly found. Sigh. Also, if
2885 allow_utf8_domains is set, allow top-bit characters. */
2887 for (t = ss; *t != 0; t++)
2888 if (!isalnum(*t) && *t != '.' && *t != '-' && *t != '_' &&
2889 (!allow_utf8_domains || *t < 128)) break;
2891 /* If the pattern is a complete domain name, with no fancy characters, look up
2892 its IP address and match against that. Note that a multi-homed host will add
2893 items to the chain. */
2904 rc = host_find_byname(&h, NULL, HOST_FIND_QUALIFY_SINGLE, NULL, FALSE);
2905 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2908 for (hh = &h; hh != NULL; hh = hh->next)
2910 if (host_is_in_net(hh->address, cb->host_address, 0)) return OK;
2914 if (rc == HOST_FIND_AGAIN) return DEFER;
2915 *error = string_sprintf("failed to find IP address for %s", ss);
2919 /* Almost all subsequent comparisons require the host name, and can be done
2920 using the general string matching function. When this function is called for
2921 outgoing hosts, the name is always given explicitly. If it is NULL, it means we
2922 must use sender_host_name and its aliases, looking them up if necessary. */
2924 if (cb->host_name != NULL) /* Explicit host name given */
2925 return match_check_string(cb->host_name, ss, -1, TRUE, TRUE, TRUE,
2928 /* Host name not given; in principle we need the sender host name and its
2929 aliases. However, for query-style lookups, we do not need the name if the
2930 query does not contain $sender_host_name. From release 4.23, a reference to
2931 $sender_host_name causes it to be looked up, so we don't need to do the lookup
2934 if ((semicolon = Ustrchr(ss, ';')) != NULL)
2937 int partial, affixlen, starflags, id;
2940 id = search_findtype_partial(ss, &partial, &affix, &affixlen, &starflags);
2943 if (id < 0) /* Unknown lookup type */
2945 log_write(0, LOG_MAIN|LOG_PANIC, "%s in host list item \"%s\"",
2946 search_error_message, ss);
2949 isquery = mac_islookup(id, lookup_querystyle|lookup_absfilequery);
2954 switch(match_check_string(US"", ss, -1, TRUE, TRUE, TRUE, valueptr))
2957 case DEFER: return DEFER;
2958 default: return FAIL;
2962 /* Not a query-style lookup; must ensure the host name is present, and then we
2963 do a check on the name and all its aliases. */
2965 if (sender_host_name == NULL)
2967 HDEBUG(D_host_lookup)
2968 debug_printf("sender host name required, to match against %s\n", ss);
2969 if (host_lookup_failed || host_name_lookup() != OK)
2971 *error = string_sprintf("failed to find host name for %s",
2972 sender_host_address);;
2975 host_build_sender_fullhost();
2978 /* Match on the sender host name, using the general matching function */
2980 switch(match_check_string(sender_host_name, ss, -1, TRUE, TRUE, TRUE,
2984 case DEFER: return DEFER;
2987 /* If there are aliases, try matching on them. */
2989 aliases = sender_host_aliases;
2990 while (*aliases != NULL)
2992 switch(match_check_string(*aliases++, ss, -1, TRUE, TRUE, TRUE, valueptr))
2995 case DEFER: return DEFER;
3004 /*************************************************
3005 * Check a specific host matches a host list *
3006 *************************************************/
3008 /* This function is passed a host list containing items in a number of
3009 different formats and the identity of a host. Its job is to determine whether
3010 the given host is in the set of hosts defined by the list. The host name is
3011 passed as a pointer so that it can be looked up if needed and not already
3012 known. This is commonly the case when called from verify_check_host() to check
3013 an incoming connection. When called from elsewhere the host name should usually
3016 This function is now just a front end to match_check_list(), which runs common
3017 code for scanning a list. We pass it the check_host() function to perform a
3021 listptr pointer to the host list
3022 cache_bits pointer to cache for named lists, or NULL
3023 host_name the host name or NULL, implying use sender_host_name and
3024 sender_host_aliases, looking them up if required
3025 host_address the IP address
3026 valueptr if not NULL, data from a lookup is passed back here
3028 Returns: OK if the host is in the defined set
3029 FAIL if the host is not in the defined set,
3030 DEFER if a data lookup deferred (not a host lookup)
3032 If the host name was needed in order to make a comparison, and could not be
3033 determined from the IP address, the result is FAIL unless the item
3034 "+allow_unknown" was met earlier in the list, in which case OK is returned. */
3037 verify_check_this_host(uschar **listptr, unsigned int *cache_bits,
3038 uschar *host_name, uschar *host_address, uschar **valueptr)
3041 unsigned int *local_cache_bits = cache_bits;
3042 uschar *save_host_address = deliver_host_address;
3043 check_host_block cb;
3044 cb.host_name = host_name;
3045 cb.host_address = host_address;
3047 if (valueptr != NULL) *valueptr = NULL;
3049 /* If the host address starts off ::ffff: it is an IPv6 address in
3050 IPv4-compatible mode. Find the IPv4 part for checking against IPv4
3053 cb.host_ipv4 = (Ustrncmp(host_address, "::ffff:", 7) == 0)?
3054 host_address + 7 : host_address;
3056 /* During the running of the check, put the IP address into $host_address. In
3057 the case of calls from the smtp transport, it will already be there. However,
3058 in other calls (e.g. when testing ignore_target_hosts), it won't. Just to be on
3059 the safe side, any existing setting is preserved, though as I write this
3060 (November 2004) I can't see any cases where it is actually needed. */
3062 deliver_host_address = host_address;
3063 rc = match_check_list(
3064 listptr, /* the list */
3065 0, /* separator character */
3066 &hostlist_anchor, /* anchor pointer */
3067 &local_cache_bits, /* cache pointer */
3068 check_host, /* function for testing */
3069 &cb, /* argument for function */
3070 MCL_HOST, /* type of check */
3071 (host_address == sender_host_address)?
3072 US"host" : host_address, /* text for debugging */
3073 valueptr); /* where to pass back data */
3074 deliver_host_address = save_host_address;
3081 /*************************************************
3082 * Check the remote host matches a list *
3083 *************************************************/
3085 /* This is a front end to verify_check_this_host(), created because checking
3086 the remote host is a common occurrence. With luck, a good compiler will spot
3087 the tail recursion and optimize it. If there's no host address, this is
3088 command-line SMTP input - check against an empty string for the address.
3091 listptr pointer to the host list
3093 Returns: the yield of verify_check_this_host(),
3094 i.e. OK, FAIL, or DEFER
3098 verify_check_host(uschar **listptr)
3100 return verify_check_this_host(listptr, sender_host_cache, NULL,
3101 (sender_host_address == NULL)? US"" : sender_host_address, NULL);
3108 /*************************************************
3109 * Invert an IP address *
3110 *************************************************/
3112 /* Originally just used for DNS xBL lists, now also used for the
3113 reverse_ip expansion operator.
3116 buffer where to put the answer
3117 address the address to invert
3121 invert_address(uschar *buffer, uschar *address)
3124 uschar *bptr = buffer;
3126 /* If this is an IPv4 address mapped into IPv6 format, adjust the pointer
3127 to the IPv4 part only. */
3129 if (Ustrncmp(address, "::ffff:", 7) == 0) address += 7;
3131 /* Handle IPv4 address: when HAVE_IPV6 is false, the result of host_aton() is
3134 if (host_aton(address, bin) == 1)
3138 for (i = 0; i < 4; i++)
3140 sprintf(CS bptr, "%d.", x & 255);
3141 while (*bptr) bptr++;
3146 /* Handle IPv6 address. Actually, as far as I know, there are no IPv6 addresses
3147 in any DNS black lists, and the format in which they will be looked up is
3148 unknown. This is just a guess. */
3154 for (j = 3; j >= 0; j--)
3157 for (i = 0; i < 8; i++)
3159 sprintf(CS bptr, "%x.", x & 15);
3160 while (*bptr) bptr++;
3167 /* Remove trailing period -- this is needed so that both arbitrary
3168 dnsbl keydomains and inverted addresses may be combined with the
3169 same format string, "%s.%s" */
3176 /*************************************************
3177 * Perform a single dnsbl lookup *
3178 *************************************************/
3180 /* This function is called from verify_check_dnsbl() below. It is also called
3181 recursively from within itself when domain and domain_txt are different
3182 pointers, in order to get the TXT record from the alternate domain.
3185 domain the outer dnsbl domain
3186 domain_txt alternate domain to lookup TXT record on success; when the
3187 same domain is to be used, domain_txt == domain (that is,
3188 the pointers must be identical, not just the text)
3189 keydomain the current keydomain (for debug message)
3190 prepend subdomain to lookup (like keydomain, but
3191 reversed if IP address)
3192 iplist the list of matching IP addresses, or NULL for "any"
3193 bitmask true if bitmask matching is wanted
3194 match_type condition for 'succeed' result
3195 0 => Any RR in iplist (=)
3196 1 => No RR in iplist (!=)
3197 2 => All RRs in iplist (==)
3198 3 => Some RRs not in iplist (!==)
3199 the two bits are defined as MT_NOT and MT_ALL
3200 defer_return what to return for a defer
3202 Returns: OK if lookup succeeded
3207 one_check_dnsbl(uschar *domain, uschar *domain_txt, uschar *keydomain,
3208 uschar *prepend, uschar *iplist, BOOL bitmask, int match_type,
3214 dnsbl_cache_block *cb;
3215 int old_pool = store_pool;
3216 uschar query[256]; /* DNS domain max length */
3218 /* Construct the specific query domainname */
3220 if (!string_format(query, sizeof(query), "%s.%s", prepend, domain))
3222 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
3223 "(ignored): %s...", query);
3227 /* Look for this query in the cache. */
3229 t = tree_search(dnsbl_cache, query);
3231 /* If not cached from a previous lookup, we must do a DNS lookup, and
3232 cache the result in permanent memory. */
3236 store_pool = POOL_PERM;
3238 /* Set up a tree entry to cache the lookup */
3240 t = store_get(sizeof(tree_node) + Ustrlen(query));
3241 Ustrcpy(t->name, query);
3242 t->data.ptr = cb = store_get(sizeof(dnsbl_cache_block));
3243 (void)tree_insertnode(&dnsbl_cache, t);
3245 /* Do the DNS loopup . */
3247 HDEBUG(D_dnsbl) debug_printf("new DNS lookup for %s\n", query);
3248 cb->rc = dns_basic_lookup(&dnsa, query, T_A);
3249 cb->text_set = FALSE;
3253 /* If the lookup succeeded, cache the RHS address. The code allows for
3254 more than one address - this was for complete generality and the possible
3255 use of A6 records. However, A6 records have been reduced to experimental
3256 status (August 2001) and may die out. So they may never get used at all,
3257 let alone in dnsbl records. However, leave the code here, just in case.
3259 Quite apart from one A6 RR generating multiple addresses, there are DNS
3260 lists that return more than one A record, so we must handle multiple
3261 addresses generated in that way as well. */
3263 if (cb->rc == DNS_SUCCEED)
3266 dns_address **addrp = &(cb->rhs);
3267 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
3269 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3271 if (rr->type == T_A)
3273 dns_address *da = dns_address_from_rr(&dnsa, rr);
3277 while (da->next != NULL) da = da->next;
3278 addrp = &(da->next);
3283 /* If we didn't find any A records, change the return code. This can
3284 happen when there is a CNAME record but there are no A records for what
3287 if (cb->rhs == NULL) cb->rc = DNS_NODATA;
3290 store_pool = old_pool;
3293 /* Previous lookup was cached */
3297 HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
3301 /* We now have the result of the DNS lookup, either newly done, or cached
3302 from a previous call. If the lookup succeeded, check against the address
3303 list if there is one. This may be a positive equality list (introduced by
3304 "="), a negative equality list (introduced by "!="), a positive bitmask
3305 list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/
3307 if (cb->rc == DNS_SUCCEED)
3309 dns_address *da = NULL;
3310 uschar *addlist = cb->rhs->address;
3312 /* For A and AAAA records, there may be multiple addresses from multiple
3313 records. For A6 records (currently not expected to be used) there may be
3314 multiple addresses from a single record. */
3316 for (da = cb->rhs->next; da != NULL; da = da->next)
3317 addlist = string_sprintf("%s, %s", addlist, da->address);
3319 HDEBUG(D_dnsbl) debug_printf("DNS lookup for %s succeeded (yielding %s)\n",
3322 /* Address list check; this can be either for equality, or via a bitmask.
3323 In the latter case, all the bits must match. */
3327 for (da = cb->rhs; da != NULL; da = da->next)
3331 uschar *ptr = iplist;
3334 /* Handle exact matching */
3338 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))) != NULL)
3340 if (Ustrcmp(CS da->address, ip) == 0) break;
3344 /* Handle bitmask matching */
3351 /* At present, all known DNS blocking lists use A records, with
3352 IPv4 addresses on the RHS encoding the information they return. I
3353 wonder if this will linger on as the last vestige of IPv4 when IPv6
3354 is ubiquitous? Anyway, for now we use paranoia code to completely
3355 ignore IPv6 addresses. The default mask is 0, which always matches.
3356 We change this only for IPv4 addresses in the list. */
3358 if (host_aton(da->address, address) == 1) mask = address[0];
3360 /* Scan the returned addresses, skipping any that are IPv6 */
3362 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))) != NULL)
3364 if (host_aton(ip, address) != 1) continue;
3365 if ((address[0] & mask) == address[0]) break;
3371 (a) An IP address in an any ('=') list matched, or
3372 (b) No IP address in an all ('==') list matched
3374 then we're done searching. */
3376 if (((match_type & MT_ALL) != 0) == (res == NULL)) break;
3379 /* If da == NULL, either
3381 (a) No IP address in an any ('=') list matched, or
3382 (b) An IP address in an all ('==') list didn't match
3384 so behave as if the DNSBL lookup had not succeeded, i.e. the host is not on
3387 if ((match_type == MT_NOT || match_type == MT_ALL) != (da == NULL))
3395 res = US"was no match";
3398 res = US"was an exclude match";
3401 res = US"was an IP address that did not match";
3404 res = US"were no IP addresses that did not match";
3407 debug_printf("=> but we are not accepting this block class because\n");
3408 debug_printf("=> there %s for %s%c%s\n",
3410 ((match_type & MT_ALL) == 0)? "" : "=",
3411 bitmask? '&' : '=', iplist);
3417 /* Either there was no IP list, or the record matched, implying that the
3418 domain is on the list. We now want to find a corresponding TXT record. If an
3419 alternate domain is specified for the TXT record, call this function
3420 recursively to look that up; this has the side effect of re-checking that
3421 there is indeed an A record at the alternate domain. */
3423 if (domain_txt != domain)
3424 return one_check_dnsbl(domain_txt, domain_txt, keydomain, prepend, NULL,
3425 FALSE, match_type, defer_return);
3427 /* If there is no alternate domain, look up a TXT record in the main domain
3428 if it has not previously been cached. */
3432 cb->text_set = TRUE;
3433 if (dns_basic_lookup(&dnsa, query, T_TXT) == DNS_SUCCEED)
3436 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
3438 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3439 if (rr->type == T_TXT) break;
3442 int len = (rr->data)[0];
3443 if (len > 511) len = 127;
3444 store_pool = POOL_PERM;
3445 cb->text = string_sprintf("%.*s", len, (const uschar *)(rr->data+1));
3446 store_pool = old_pool;
3451 dnslist_value = addlist;
3452 dnslist_text = cb->text;
3456 /* There was a problem with the DNS lookup */
3458 if (cb->rc != DNS_NOMATCH && cb->rc != DNS_NODATA)
3460 log_write(L_dnslist_defer, LOG_MAIN,
3461 "DNS list lookup defer (probably timeout) for %s: %s", query,
3462 (defer_return == OK)? US"assumed in list" :
3463 (defer_return == FAIL)? US"assumed not in list" :
3464 US"returned DEFER");
3465 return defer_return;
3468 /* No entry was found in the DNS; continue for next domain */
3472 debug_printf("DNS lookup for %s failed\n", query);
3473 debug_printf("=> that means %s is not listed at %s\n",
3483 /*************************************************
3484 * Check host against DNS black lists *
3485 *************************************************/
3487 /* This function runs checks against a list of DNS black lists, until one
3488 matches. Each item on the list can be of the form
3490 domain=ip-address/key
3492 The domain is the right-most domain that is used for the query, for example,
3493 blackholes.mail-abuse.org. If the IP address is present, there is a match only
3494 if the DNS lookup returns a matching IP address. Several addresses may be
3495 given, comma-separated, for example: x.y.z=127.0.0.1,127.0.0.2.
3497 If no key is given, what is looked up in the domain is the inverted IP address
3498 of the current client host. If a key is given, it is used to construct the
3499 domain for the lookup. For example:
3501 dsn.rfc-ignorant.org/$sender_address_domain
3503 After finding a match in the DNS, the domain is placed in $dnslist_domain, and
3504 then we check for a TXT record for an error message, and if found, save its
3505 value in $dnslist_text. We also cache everything in a tree, to optimize
3508 The TXT record is normally looked up in the same domain as the A record, but
3509 when many lists are combined in a single DNS domain, this will not be a very
3510 specific message. It is possible to specify a different domain for looking up
3511 TXT records; this is given before the main domain, comma-separated. For
3514 dnslists = http.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.2 : \
3515 socks.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.3
3517 The caching ensures that only one lookup in dnsbl.sorbs.net is done.
3519 Note: an address for testing RBL is 192.203.178.39
3520 Note: an address for testing DUL is 192.203.178.4
3521 Note: a domain for testing RFCI is example.tld.dsn.rfc-ignorant.org
3524 listptr the domain/address/data list
3526 Returns: OK successful lookup (i.e. the address is on the list), or
3527 lookup deferred after +include_unknown
3528 FAIL name not found, or no data found for the given type, or
3529 lookup deferred after +exclude_unknown (default)
3530 DEFER lookup failure, if +defer_unknown was set
3534 verify_check_dnsbl(uschar **listptr)
3537 int defer_return = FAIL;
3538 uschar *list = *listptr;
3541 uschar buffer[1024];
3542 uschar revadd[128]; /* Long enough for IPv6 address */
3544 /* Indicate that the inverted IP address is not yet set up */
3548 /* In case this is the first time the DNS resolver is being used. */
3550 dns_init(FALSE, FALSE, FALSE); /*XXX dnssec? */
3552 /* Loop through all the domains supplied, until something matches */
3554 while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
3557 BOOL bitmask = FALSE;
3564 HDEBUG(D_dnsbl) debug_printf("DNS list check: %s\n", domain);
3566 /* Deal with special values that change the behaviour on defer */
3568 if (domain[0] == '+')
3570 if (strcmpic(domain, US"+include_unknown") == 0) defer_return = OK;
3571 else if (strcmpic(domain, US"+exclude_unknown") == 0) defer_return = FAIL;
3572 else if (strcmpic(domain, US"+defer_unknown") == 0) defer_return = DEFER;
3574 log_write(0, LOG_MAIN|LOG_PANIC, "unknown item in dnslist (ignored): %s",
3579 /* See if there's explicit data to be looked up */
3581 key = Ustrchr(domain, '/');
3582 if (key != NULL) *key++ = 0;
3584 /* See if there's a list of addresses supplied after the domain name. This is
3585 introduced by an = or a & character; if preceded by = we require all matches
3586 and if preceded by ! we invert the result. */
3588 iplist = Ustrchr(domain, '=');
3592 iplist = Ustrchr(domain, '&');
3595 if (iplist != NULL) /* Found either = or & */
3597 if (iplist > domain && iplist[-1] == '!') /* Handle preceding ! */
3599 match_type |= MT_NOT;
3603 *iplist++ = 0; /* Terminate domain, move on */
3605 /* If we found = (bitmask == FALSE), check for == or =& */
3607 if (!bitmask && (*iplist == '=' || *iplist == '&'))
3609 bitmask = *iplist++ == '&';
3610 match_type |= MT_ALL;
3614 /* If there is a comma in the domain, it indicates that a second domain for
3615 looking up TXT records is provided, before the main domain. Otherwise we must
3616 set domain_txt == domain. */
3618 domain_txt = domain;
3619 comma = Ustrchr(domain, ',');
3626 /* Check that what we have left is a sensible domain name. There is no reason
3627 why these domains should in fact use the same syntax as hosts and email
3628 domains, but in practice they seem to. However, there is little point in
3629 actually causing an error here, because that would no doubt hold up incoming
3630 mail. Instead, I'll just log it. */
3632 for (s = domain; *s != 0; s++)
3634 if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_')
3636 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
3637 "strange characters - is this right?", domain);
3642 /* Check the alternate domain if present */
3644 if (domain_txt != domain) for (s = domain_txt; *s != 0; s++)
3646 if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_')
3648 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
3649 "strange characters - is this right?", domain_txt);
3654 /* If there is no key string, construct the query by adding the domain name
3655 onto the inverted host address, and perform a single DNS lookup. */
3659 if (sender_host_address == NULL) return FAIL; /* can never match */
3660 if (revadd[0] == 0) invert_address(revadd, sender_host_address);
3661 rc = one_check_dnsbl(domain, domain_txt, sender_host_address, revadd,
3662 iplist, bitmask, match_type, defer_return);
3665 dnslist_domain = string_copy(domain_txt);
3666 dnslist_matched = string_copy(sender_host_address);
3667 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
3668 sender_host_address, dnslist_domain);
3670 if (rc != FAIL) return rc; /* OK or DEFER */
3673 /* If there is a key string, it can be a list of domains or IP addresses to
3674 be concatenated with the main domain. */
3681 uschar keybuffer[256];
3682 uschar keyrevadd[128];
3684 while ((keydomain = string_nextinlist(&key, &keysep, keybuffer,
3685 sizeof(keybuffer))) != NULL)
3687 uschar *prepend = keydomain;
3689 if (string_is_ip_address(keydomain, NULL) != 0)
3691 invert_address(keyrevadd, keydomain);
3692 prepend = keyrevadd;
3695 rc = one_check_dnsbl(domain, domain_txt, keydomain, prepend, iplist,
3696 bitmask, match_type, defer_return);
3700 dnslist_domain = string_copy(domain_txt);
3701 dnslist_matched = string_copy(keydomain);
3702 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
3703 keydomain, dnslist_domain);
3707 /* If the lookup deferred, remember this fact. We keep trying the rest
3708 of the list to see if we get a useful result, and if we don't, we return
3709 DEFER at the end. */
3711 if (rc == DEFER) defer = TRUE;
3712 } /* continue with next keystring domain/address */
3714 if (defer) return DEFER;
3716 } /* continue with next dnsdb outer domain */
3723 /* End of verify.c */