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 &canonical_name, NULL);
1759 /* Can only do a callout if we have at least one host! If the callout
1760 fails, it will have set ${sender,recipient}_verify_failure. */
1762 if (host_list != NULL)
1764 HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n");
1765 if (host_checking && !host_checking_callout)
1768 debug_printf("... callout omitted by default when host testing\n"
1769 "(Use -bhc if you want the callouts to happen.)\n");
1774 deliver_set_expansions(addr);
1776 rc = do_callout(addr, host_list, &tf, callout, callout_overall,
1777 callout_connect, options, se_mailfrom, pm_mailfrom);
1782 HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor "
1783 "transport provided a host list\n");
1788 /* Otherwise, any failure is a routing failure */
1790 else *failure_ptr = US"route";
1792 /* A router may return REROUTED if it has set up a child address as a result
1793 of a change of domain name (typically from widening). In this case we always
1794 want to continue to verify the new child. */
1796 if (rc == REROUTED) continue;
1798 /* Handle hard failures */
1805 address_item *p = addr->parent;
1807 respond_printf(f, "%s%s %s", ko_prefix,
1808 full_info? addr->address : address,
1809 address_test_mode? "is undeliverable" : "failed to verify");
1810 if (!expn && admin_user)
1812 if (addr->basic_errno > 0)
1813 respond_printf(f, ": %s", strerror(addr->basic_errno));
1814 if (addr->message != NULL)
1815 respond_printf(f, ": %s", addr->message);
1818 /* Show parents iff doing full info */
1820 if (full_info) while (p != NULL)
1822 respond_printf(f, "%s\n <-- %s", cr, p->address);
1825 respond_printf(f, "%s\n", cr);
1827 cancel_cutthrough_connection("routing hard fail");
1831 yield = copy_error(vaddr, addr, FAIL);
1839 else if (rc == DEFER)
1844 address_item *p = addr->parent;
1845 respond_printf(f, "%s%s cannot be resolved at this time", ko_prefix,
1846 full_info? addr->address : address);
1847 if (!expn && admin_user)
1849 if (addr->basic_errno > 0)
1850 respond_printf(f, ": %s", strerror(addr->basic_errno));
1851 if (addr->message != NULL)
1852 respond_printf(f, ": %s", addr->message);
1853 else if (addr->basic_errno <= 0)
1854 respond_printf(f, ": unknown error");
1857 /* Show parents iff doing full info */
1859 if (full_info) while (p != NULL)
1861 respond_printf(f, "%s\n <-- %s", cr, p->address);
1864 respond_printf(f, "%s\n", cr);
1866 cancel_cutthrough_connection("routing soft fail");
1870 yield = copy_error(vaddr, addr, DEFER);
1873 else if (yield == OK) yield = DEFER;
1876 /* If we are handling EXPN, we do not want to continue to route beyond
1877 the top level (whose address is in "address"). */
1881 uschar *ok_prefix = US"250-";
1882 if (addr_new == NULL)
1884 if (addr_local == NULL && addr_remote == NULL)
1885 respond_printf(f, "250 mail to <%s> is discarded\r\n", address);
1887 respond_printf(f, "250 <%s>\r\n", address);
1889 else while (addr_new != NULL)
1891 address_item *addr2 = addr_new;
1892 addr_new = addr2->next;
1893 if (addr_new == NULL) ok_prefix = US"250 ";
1894 respond_printf(f, "%s<%s>\r\n", ok_prefix, addr2->address);
1900 /* Successful routing other than EXPN. */
1904 /* Handle successful routing when short info wanted. Otherwise continue for
1905 other (generated) addresses. Short info is the operational case. Full info
1906 can be requested only when debug_selector != 0 and a file is supplied.
1908 There is a conflict between the use of aliasing as an alternate email
1909 address, and as a sort of mailing list. If an alias turns the incoming
1910 address into just one address (e.g. J.Caesar->jc44) you may well want to
1911 carry on verifying the generated address to ensure it is valid when
1912 checking incoming mail. If aliasing generates multiple addresses, you
1913 probably don't want to do this. Exim therefore treats the generation of
1914 just a single new address as a special case, and continues on to verify the
1915 generated address. */
1917 if (!full_info && /* Stop if short info wanted AND */
1918 (((addr_new == NULL || /* No new address OR */
1919 addr_new->next != NULL || /* More than one new address OR */
1920 testflag(addr_new, af_pfr))) /* New address is pfr */
1922 (addr_new != NULL && /* At least one new address AND */
1923 success_on_redirect))) /* success_on_redirect is set */
1925 if (f != NULL) fprintf(f, "%s %s\n", address,
1926 address_test_mode? "is deliverable" : "verified");
1928 /* If we have carried on to verify a child address, we want the value
1929 of $address_data to be that of the child */
1931 vaddr->p.address_data = addr->p.address_data;
1936 } /* Loop for generated addresses */
1938 /* Display the full results of the successful routing, including any generated
1939 addresses. Control gets here only when full_info is set, which requires f not
1940 to be NULL, and this occurs only when a top-level verify is called with the
1941 debugging switch on.
1943 If there are no local and no remote addresses, and there were no pipes, files,
1944 or autoreplies, and there were no errors or deferments, the message is to be
1945 discarded, usually because of the use of :blackhole: in an alias file. */
1947 if (allok && addr_local == NULL && addr_remote == NULL)
1949 fprintf(f, "mail to %s is discarded\n", address);
1953 for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++)
1955 while (addr_list != NULL)
1957 address_item *addr = addr_list;
1958 address_item *p = addr->parent;
1959 addr_list = addr->next;
1961 fprintf(f, "%s", CS addr->address);
1962 #ifdef EXPERIMENTAL_SRS
1963 if(addr->p.srs_sender)
1964 fprintf(f, " [srs = %s]", addr->p.srs_sender);
1967 /* If the address is a duplicate, show something about it. */
1969 if (!testflag(addr, af_pfr))
1972 if ((tnode = tree_search(tree_duplicates, addr->unique)) != NULL)
1973 fprintf(f, " [duplicate, would not be delivered]");
1974 else tree_add_duplicate(addr->unique, addr);
1977 /* Now show its parents */
1981 fprintf(f, "\n <-- %s", p->address);
1986 /* Show router, and transport */
1988 fprintf(f, "router = %s, ", addr->router->name);
1989 fprintf(f, "transport = %s\n", (addr->transport == NULL)? US"unset" :
1990 addr->transport->name);
1992 /* Show any hosts that are set up by a router unless the transport
1993 is going to override them; fiddle a bit to get a nice format. */
1995 if (addr->host_list != NULL && addr->transport != NULL &&
1996 !addr->transport->overrides_hosts)
2001 for (h = addr->host_list; h != NULL; h = h->next)
2003 int len = Ustrlen(h->name);
2004 if (len > maxlen) maxlen = len;
2005 len = (h->address != NULL)? Ustrlen(h->address) : 7;
2006 if (len > maxaddlen) maxaddlen = len;
2008 for (h = addr->host_list; h != NULL; h = h->next)
2010 int len = Ustrlen(h->name);
2011 fprintf(f, " host %s ", h->name);
2012 while (len++ < maxlen) fprintf(f, " ");
2013 if (h->address != NULL)
2015 fprintf(f, "[%s] ", h->address);
2016 len = Ustrlen(h->address);
2018 else if (!addr->transport->info->local) /* Omit [unknown] for local */
2020 fprintf(f, "[unknown] ");
2024 while (len++ < maxaddlen) fprintf(f," ");
2025 if (h->mx >= 0) fprintf(f, "MX=%d", h->mx);
2026 if (h->port != PORT_NONE) fprintf(f, " port=%d", h->port);
2027 if (h->status == hstatus_unusable) fprintf(f, " ** unusable **");
2034 /* Yield will be DEFER or FAIL if any one address has, only for full_info (which is
2035 the -bv or -bt case). */
2038 tls_modify_variables(&tls_in);
2046 /*************************************************
2047 * Check headers for syntax errors *
2048 *************************************************/
2050 /* This function checks those header lines that contain addresses, and verifies
2051 that all the addresses therein are syntactially correct.
2054 msgptr where to put an error message
2061 verify_check_headers(uschar **msgptr)
2067 for (h = header_list; h != NULL && yield == OK; h = h->next)
2069 if (h->type != htype_from &&
2070 h->type != htype_reply_to &&
2071 h->type != htype_sender &&
2072 h->type != htype_to &&
2073 h->type != htype_cc &&
2074 h->type != htype_bcc)
2077 colon = Ustrchr(h->text, ':');
2079 while (isspace(*s)) s++;
2081 /* Loop for multiple addresses in the header, enabling group syntax. Note
2082 that we have to reset this after the header has been scanned. */
2084 parse_allow_group = TRUE;
2088 uschar *ss = parse_find_address_end(s, FALSE);
2089 uschar *recipient, *errmess;
2090 int terminator = *ss;
2091 int start, end, domain;
2093 /* Temporarily terminate the string at this point, and extract the
2094 operative address within, allowing group syntax. */
2097 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2100 /* Permit an unqualified address only if the message is local, or if the
2101 sending host is configured to be permitted to send them. */
2103 if (recipient != NULL && domain == 0)
2105 if (h->type == htype_from || h->type == htype_sender)
2107 if (!allow_unqualified_sender) recipient = NULL;
2111 if (!allow_unqualified_recipient) recipient = NULL;
2113 if (recipient == NULL) errmess = US"unqualified address not permitted";
2116 /* It's an error if no address could be extracted, except for the special
2117 case of an empty address. */
2119 if (recipient == NULL && Ustrcmp(errmess, "empty address") != 0)
2121 uschar *verb = US"is";
2126 /* Arrange not to include any white space at the end in the
2127 error message or the header name. */
2129 while (t > s && isspace(t[-1])) t--;
2130 while (tt > h->text && isspace(tt[-1])) tt--;
2132 /* Add the address that failed to the error message, since in a
2133 header with very many addresses it is sometimes hard to spot
2134 which one is at fault. However, limit the amount of address to
2135 quote - cases have been seen where, for example, a missing double
2136 quote in a humungous To: header creates an "address" that is longer
2137 than string_sprintf can handle. */
2146 *msgptr = string_printing(
2147 string_sprintf("%s: failing address in \"%.*s:\" header %s: %.*s",
2148 errmess, tt - h->text, h->text, verb, len, s));
2151 break; /* Out of address loop */
2154 /* Advance to the next address */
2156 s = ss + (terminator? 1:0);
2157 while (isspace(*s)) s++;
2158 } /* Next address */
2160 parse_allow_group = FALSE;
2161 parse_found_group = FALSE;
2162 } /* Next header unless yield has been set FALSE */
2168 /*************************************************
2169 * Check header names for 8-bit characters *
2170 *************************************************/
2172 /* This function checks for invalid charcters in header names. See
2173 RFC 5322, 2.2. and RFC 6532, 3.
2176 msgptr where to put an error message
2183 verify_check_header_names_ascii(uschar **msgptr)
2188 for (h = header_list; h != NULL; h = h->next)
2190 colon = Ustrchr(h->text, ':');
2191 for(s = h->text; s < colon; s++)
2193 if ((*s < 33) || (*s > 126))
2195 *msgptr = string_sprintf("Invalid character in header \"%.*s\" found",
2196 colon - h->text, h->text);
2204 /*************************************************
2205 * Check for blind recipients *
2206 *************************************************/
2208 /* This function checks that every (envelope) recipient is mentioned in either
2209 the To: or Cc: header lines, thus detecting blind carbon copies.
2211 There are two ways of scanning that could be used: either scan the header lines
2212 and tick off the recipients, or scan the recipients and check the header lines.
2213 The original proposed patch did the former, but I have chosen to do the latter,
2214 because (a) it requires no memory and (b) will use fewer resources when there
2215 are many addresses in To: and/or Cc: and only one or two envelope recipients.
2218 Returns: OK if there are no blind recipients
2219 FAIL if there is at least one blind recipient
2223 verify_check_notblind(void)
2226 for (i = 0; i < recipients_count; i++)
2230 uschar *address = recipients_list[i].address;
2232 for (h = header_list; !found && h != NULL; h = h->next)
2236 if (h->type != htype_to && h->type != htype_cc) continue;
2238 colon = Ustrchr(h->text, ':');
2240 while (isspace(*s)) s++;
2242 /* Loop for multiple addresses in the header, enabling group syntax. Note
2243 that we have to reset this after the header has been scanned. */
2245 parse_allow_group = TRUE;
2249 uschar *ss = parse_find_address_end(s, FALSE);
2250 uschar *recipient,*errmess;
2251 int terminator = *ss;
2252 int start, end, domain;
2254 /* Temporarily terminate the string at this point, and extract the
2255 operative address within, allowing group syntax. */
2258 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2261 /* If we found a valid recipient that has a domain, compare it with the
2262 envelope recipient. Local parts are compared case-sensitively, domains
2263 case-insensitively. By comparing from the start with length "domain", we
2264 include the "@" at the end, which ensures that we are comparing the whole
2265 local part of each address. */
2267 if (recipient != NULL && domain != 0)
2269 found = Ustrncmp(recipient, address, domain) == 0 &&
2270 strcmpic(recipient + domain, address + domain) == 0;
2274 /* Advance to the next address */
2276 s = ss + (terminator? 1:0);
2277 while (isspace(*s)) s++;
2278 } /* Next address */
2280 parse_allow_group = FALSE;
2281 parse_found_group = FALSE;
2282 } /* Next header (if found is false) */
2284 if (!found) return FAIL;
2285 } /* Next recipient */
2292 /*************************************************
2293 * Find if verified sender *
2294 *************************************************/
2296 /* Usually, just a single address is verified as the sender of the message.
2297 However, Exim can be made to verify other addresses as well (often related in
2298 some way), and this is useful in some environments. There may therefore be a
2299 chain of such addresses that have previously been tested. This function finds
2300 whether a given address is on the chain.
2302 Arguments: the address to be verified
2303 Returns: pointer to an address item, or NULL
2307 verify_checked_sender(uschar *sender)
2310 for (addr = sender_verified_list; addr != NULL; addr = addr->next)
2311 if (Ustrcmp(sender, addr->address) == 0) break;
2319 /*************************************************
2320 * Get valid header address *
2321 *************************************************/
2323 /* Scan the originator headers of the message, looking for an address that
2324 verifies successfully. RFC 822 says:
2326 o The "Sender" field mailbox should be sent notices of
2327 any problems in transport or delivery of the original
2328 messages. If there is no "Sender" field, then the
2329 "From" field mailbox should be used.
2331 o If the "Reply-To" field exists, then the reply should
2332 go to the addresses indicated in that field and not to
2333 the address(es) indicated in the "From" field.
2335 So we check a Sender field if there is one, else a Reply_to field, else a From
2336 field. As some strange messages may have more than one of these fields,
2337 especially if they are resent- fields, check all of them if there is more than
2341 user_msgptr points to where to put a user error message
2342 log_msgptr points to where to put a log error message
2343 callout timeout for callout check (passed to verify_address())
2344 callout_overall overall callout timeout (ditto)
2345 callout_connect connect callout timeout (ditto)
2346 se_mailfrom mailfrom for verify; NULL => ""
2347 pm_mailfrom sender for pm callout check (passed to verify_address())
2348 options callout options (passed to verify_address())
2349 verrno where to put the address basic_errno
2351 If log_msgptr is set to something without setting user_msgptr, the caller
2352 normally uses log_msgptr for both things.
2354 Returns: result of the verification attempt: OK, FAIL, or DEFER;
2355 FAIL is given if no appropriate headers are found
2359 verify_check_header_address(uschar **user_msgptr, uschar **log_msgptr,
2360 int callout, int callout_overall, int callout_connect, uschar *se_mailfrom,
2361 uschar *pm_mailfrom, int options, int *verrno)
2363 static int header_types[] = { htype_sender, htype_reply_to, htype_from };
2368 for (i = 0; i < 3 && !done; i++)
2371 for (h = header_list; h != NULL && !done; h = h->next)
2373 int terminator, new_ok;
2374 uschar *s, *ss, *endname;
2376 if (h->type != header_types[i]) continue;
2377 s = endname = Ustrchr(h->text, ':') + 1;
2379 /* Scan the addresses in the header, enabling group syntax. Note that we
2380 have to reset this after the header has been scanned. */
2382 parse_allow_group = TRUE;
2386 address_item *vaddr;
2388 while (isspace(*s) || *s == ',') s++;
2389 if (*s == 0) break; /* End of header */
2391 ss = parse_find_address_end(s, FALSE);
2393 /* The terminator is a comma or end of header, but there may be white
2394 space preceding it (including newline for the last address). Move back
2395 past any white space so we can check against any cached envelope sender
2396 address verifications. */
2398 while (isspace(ss[-1])) ss--;
2402 HDEBUG(D_verify) debug_printf("verifying %.*s header address %s\n",
2403 (int)(endname - h->text), h->text, s);
2405 /* See if we have already verified this address as an envelope sender,
2406 and if so, use the previous answer. */
2408 vaddr = verify_checked_sender(s);
2410 if (vaddr != NULL && /* Previously checked */
2411 (callout <= 0 || /* No callout needed; OR */
2412 vaddr->special_action > 256)) /* Callout was done */
2414 new_ok = vaddr->special_action & 255;
2415 HDEBUG(D_verify) debug_printf("previously checked as envelope sender\n");
2416 *ss = terminator; /* Restore shortened string */
2419 /* Otherwise we run the verification now. We must restore the shortened
2420 string before running the verification, so the headers are correct, in
2421 case there is any rewriting. */
2425 int start, end, domain;
2426 uschar *address = parse_extract_address(s, log_msgptr, &start, &end,
2431 /* If we found an empty address, just carry on with the next one, but
2432 kill the message. */
2434 if (address == NULL && Ustrcmp(*log_msgptr, "empty address") == 0)
2441 /* If verification failed because of a syntax error, fail this
2442 function, and ensure that the failing address gets added to the error
2445 if (address == NULL)
2448 while (ss > s && isspace(ss[-1])) ss--;
2449 *log_msgptr = string_sprintf("syntax error in '%.*s' header when "
2450 "scanning for sender: %s in \"%.*s\"",
2451 endname - h->text, h->text, *log_msgptr, ss - s, s);
2457 /* Else go ahead with the sender verification. But it isn't *the*
2458 sender of the message, so set vopt_fake_sender to stop sender_address
2459 being replaced after rewriting or qualification. */
2463 vaddr = deliver_make_addr(address, FALSE);
2464 new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender,
2465 callout, callout_overall, callout_connect, se_mailfrom,
2470 /* We now have the result, either newly found, or cached. If we are
2471 giving out error details, set a specific user error. This means that the
2472 last of these will be returned to the user if all three fail. We do not
2473 set a log message - the generic one below will be used. */
2477 *verrno = vaddr->basic_errno;
2478 if (smtp_return_error_details)
2480 *user_msgptr = string_sprintf("Rejected after DATA: "
2481 "could not verify \"%.*s\" header address\n%s: %s",
2482 endname - h->text, h->text, vaddr->address, vaddr->message);
2486 /* Success or defer */
2495 if (new_ok == DEFER) yield = DEFER;
2497 /* Move on to any more addresses in the header */
2500 } /* Next address */
2502 parse_allow_group = FALSE;
2503 parse_found_group = FALSE;
2504 } /* Next header, unless done */
2505 } /* Next header type unless done */
2507 if (yield == FAIL && *log_msgptr == NULL)
2508 *log_msgptr = US"there is no valid sender in any header line";
2510 if (yield == DEFER && *log_msgptr == NULL)
2511 *log_msgptr = US"all attempts to verify a sender in a header line deferred";
2519 /*************************************************
2520 * Get RFC 1413 identification *
2521 *************************************************/
2523 /* Attempt to get an id from the sending machine via the RFC 1413 protocol. If
2524 the timeout is set to zero, then the query is not done. There may also be lists
2525 of hosts and nets which are exempt. To guard against malefactors sending
2526 non-printing characters which could, for example, disrupt a message's headers,
2527 make sure the string consists of printing characters only.
2530 port the port to connect to; usually this is IDENT_PORT (113), but when
2531 running in the test harness with -bh a different value is used.
2535 Side effect: any received ident value is put in sender_ident (NULL otherwise)
2539 verify_get_ident(int port)
2541 int sock, host_af, qlen;
2542 int received_sender_port, received_interface_port, n;
2544 uschar buffer[2048];
2546 /* Default is no ident. Check whether we want to do an ident check for this
2549 sender_ident = NULL;
2550 if (rfc1413_query_timeout <= 0 || verify_check_host(&rfc1413_hosts) != OK)
2553 DEBUG(D_ident) debug_printf("doing ident callback\n");
2555 /* Set up a connection to the ident port of the remote host. Bind the local end
2556 to the incoming interface address. If the sender host address is an IPv6
2557 address, the incoming interface address will also be IPv6. */
2559 host_af = (Ustrchr(sender_host_address, ':') == NULL)? AF_INET : AF_INET6;
2560 sock = ip_socket(SOCK_STREAM, host_af);
2561 if (sock < 0) return;
2563 if (ip_bind(sock, host_af, interface_address, 0) < 0)
2565 DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n",
2570 if (ip_connect(sock, host_af, sender_host_address, port, rfc1413_query_timeout)
2573 if (errno == ETIMEDOUT && (log_extra_selector & LX_ident_timeout) != 0)
2575 log_write(0, LOG_MAIN, "ident connection to %s timed out",
2576 sender_host_address);
2580 DEBUG(D_ident) debug_printf("ident connection to %s failed: %s\n",
2581 sender_host_address, strerror(errno));
2586 /* Construct and send the query. */
2588 sprintf(CS buffer, "%d , %d\r\n", sender_host_port, interface_port);
2589 qlen = Ustrlen(buffer);
2590 if (send(sock, buffer, qlen, 0) < 0)
2592 DEBUG(D_ident) debug_printf("ident send failed: %s\n", strerror(errno));
2596 /* Read a response line. We put it into the rest of the buffer, using several
2597 recv() calls if necessary. */
2605 int size = sizeof(buffer) - (p - buffer);
2607 if (size <= 0) goto END_OFF; /* Buffer filled without seeing \n. */
2608 count = ip_recv(sock, p, size, rfc1413_query_timeout);
2609 if (count <= 0) goto END_OFF; /* Read error or EOF */
2611 /* Scan what we just read, to see if we have reached the terminating \r\n. Be
2612 generous, and accept a plain \n terminator as well. The only illegal
2615 for (pp = p; pp < p + count; pp++)
2617 if (*pp == 0) goto END_OFF; /* Zero octet not allowed */
2620 if (pp[-1] == '\r') pp--;
2622 goto GOT_DATA; /* Break out of both loops */
2626 /* Reached the end of the data without finding \n. Let the loop continue to
2627 read some more, if there is room. */
2634 /* We have received a line of data. Check it carefully. It must start with the
2635 same two port numbers that we sent, followed by data as defined by the RFC. For
2638 12345 , 25 : USERID : UNIX :root
2640 However, the amount of white space may be different to what we sent. In the
2641 "osname" field there may be several sub-fields, comma separated. The data we
2642 actually want to save follows the third colon. Some systems put leading spaces
2643 in it - we discard those. */
2645 if (sscanf(CS buffer + qlen, "%d , %d%n", &received_sender_port,
2646 &received_interface_port, &n) != 2 ||
2647 received_sender_port != sender_host_port ||
2648 received_interface_port != interface_port)
2651 p = buffer + qlen + n;
2652 while(isspace(*p)) p++;
2653 if (*p++ != ':') goto END_OFF;
2654 while(isspace(*p)) p++;
2655 if (Ustrncmp(p, "USERID", 6) != 0) goto END_OFF;
2657 while(isspace(*p)) p++;
2658 if (*p++ != ':') goto END_OFF;
2659 while (*p != 0 && *p != ':') p++;
2660 if (*p++ == 0) goto END_OFF;
2661 while(isspace(*p)) p++;
2662 if (*p == 0) goto END_OFF;
2664 /* The rest of the line is the data we want. We turn it into printing
2665 characters when we save it, so that it cannot mess up the format of any logging
2666 or Received: lines into which it gets inserted. We keep a maximum of 127
2669 sender_ident = string_printing(string_copyn(p, 127));
2670 DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident);
2680 /*************************************************
2681 * Match host to a single host-list item *
2682 *************************************************/
2684 /* This function compares a host (name or address) against a single item
2685 from a host list. The host name gets looked up if it is needed and is not
2686 already known. The function is called from verify_check_this_host() via
2687 match_check_list(), which is why most of its arguments are in a single block.
2690 arg the argument block (see below)
2691 ss the host-list item
2692 valueptr where to pass back looked up data, or NULL
2693 error for error message when returning ERROR
2696 host_name (a) the host name, or
2697 (b) NULL, implying use sender_host_name and
2698 sender_host_aliases, looking them up if required, or
2699 (c) the empty string, meaning that only IP address matches
2701 host_address the host address
2702 host_ipv4 the IPv4 address taken from an IPv6 one
2706 DEFER lookup deferred
2707 ERROR (a) failed to find the host name or IP address, or
2708 (b) unknown lookup type specified, or
2709 (c) host name encountered when only IP addresses are
2714 check_host(void *arg, uschar *ss, uschar **valueptr, uschar **error)
2716 check_host_block *cb = (check_host_block *)arg;
2719 BOOL iplookup = FALSE;
2720 BOOL isquery = FALSE;
2721 BOOL isiponly = cb->host_name != NULL && cb->host_name[0] == 0;
2726 /* Optimize for the special case when the pattern is "*". */
2728 if (*ss == '*' && ss[1] == 0) return OK;
2730 /* If the pattern is empty, it matches only in the case when there is no host -
2731 this can occur in ACL checking for SMTP input using the -bs option. In this
2732 situation, the host address is the empty string. */
2734 if (cb->host_address[0] == 0) return (*ss == 0)? OK : FAIL;
2735 if (*ss == 0) return FAIL;
2737 /* If the pattern is precisely "@" then match against the primary host name,
2738 provided that host name matching is permitted; if it's "@[]" match against the
2739 local host's IP addresses. */
2745 if (isiponly) return ERROR;
2746 ss = primary_hostname;
2748 else if (Ustrcmp(ss, "@[]") == 0)
2750 ip_address_item *ip;
2751 for (ip = host_find_interfaces(); ip != NULL; ip = ip->next)
2752 if (Ustrcmp(ip->address, cb->host_address) == 0) return OK;
2757 /* If the pattern is an IP address, optionally followed by a bitmask count, do
2758 a (possibly masked) comparision with the current IP address. */
2760 if (string_is_ip_address(ss, &maskoffset) != 0)
2761 return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL);
2763 /* The pattern is not an IP address. A common error that people make is to omit
2764 one component of an IPv4 address, either by accident, or believing that, for
2765 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,
2766 which it isn't. (Those applications that do accept 1.2.3 as an IP address
2767 interpret it as 1.2.0.3 because the final component becomes 16-bit - this is an
2768 ancient specification.) To aid in debugging these cases, we give a specific
2769 error if the pattern contains only digits and dots or contains a slash preceded
2770 only by digits and dots (a slash at the start indicates a file name and of
2771 course slashes may be present in lookups, but not preceded only by digits and
2774 for (t = ss; isdigit(*t) || *t == '.'; t++);
2775 if (*t == 0 || (*t == '/' && t != ss))
2777 *error = US"malformed IPv4 address or address mask";
2781 /* See if there is a semicolon in the pattern */
2783 semicolon = Ustrchr(ss, ';');
2785 /* If we are doing an IP address only match, then all lookups must be IP
2786 address lookups, even if there is no "net-". */
2790 iplookup = semicolon != NULL;
2793 /* Otherwise, if the item is of the form net[n]-lookup;<file|query> then it is
2794 a lookup on a masked IP network, in textual form. We obey this code even if we
2795 have already set iplookup, so as to skip over the "net-" prefix and to set the
2796 mask length. The net- stuff really only applies to single-key lookups where the
2797 key is implicit. For query-style lookups the key is specified in the query.
2798 From release 4.30, the use of net- for query style is no longer needed, but we
2799 retain it for backward compatibility. */
2801 if (Ustrncmp(ss, "net", 3) == 0 && semicolon != NULL)
2804 for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0';
2805 if (mlen == 0 && t == ss+3) mlen = -1; /* No mask supplied */
2806 iplookup = (*t++ == '-');
2810 /* Do the IP address lookup if that is indeed what we have */
2818 uschar *filename, *key, *result;
2821 /* Find the search type */
2823 search_type = search_findtype(t, semicolon - t);
2825 if (search_type < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
2826 search_error_message);
2828 /* Adjust parameters for the type of lookup. For a query-style lookup, there
2829 is no file name, and the "key" is just the query. For query-style with a file
2830 name, we have to fish the file off the start of the query. For a single-key
2831 lookup, the key is the current IP address, masked appropriately, and
2832 reconverted to text form, with the mask appended. For IPv6 addresses, specify
2833 dot separators instead of colons, except when the lookup type is "iplsearch".
2836 if (mac_islookup(search_type, lookup_absfilequery))
2838 filename = semicolon + 1;
2840 while (*key != 0 && !isspace(*key)) key++;
2841 filename = string_copyn(filename, key - filename);
2842 while (isspace(*key)) key++;
2844 else if (mac_islookup(search_type, lookup_querystyle))
2847 key = semicolon + 1;
2849 else /* Single-key style */
2851 int sep = (Ustrcmp(lookup_list[search_type]->name, "iplsearch") == 0)?
2853 insize = host_aton(cb->host_address, incoming);
2854 host_mask(insize, incoming, mlen);
2855 (void)host_nmtoa(insize, incoming, mlen, buffer, sep);
2857 filename = semicolon + 1;
2860 /* Now do the actual lookup; note that there is no search_close() because
2861 of the caching arrangements. */
2863 handle = search_open(filename, search_type, 0, NULL, NULL);
2864 if (handle == NULL) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
2865 search_error_message);
2866 result = search_find(handle, filename, key, -1, NULL, 0, 0, NULL);
2867 if (valueptr != NULL) *valueptr = result;
2868 return (result != NULL)? OK : search_find_defer? DEFER: FAIL;
2871 /* The pattern is not an IP address or network reference of any kind. That is,
2872 it is a host name pattern. If this is an IP only match, there's an error in the
2877 *error = US"cannot match host name in match_ip list";
2881 /* Check the characters of the pattern to see if they comprise only letters,
2882 digits, full stops, and hyphens (the constituents of domain names). Allow
2883 underscores, as they are all too commonly found. Sigh. Also, if
2884 allow_utf8_domains is set, allow top-bit characters. */
2886 for (t = ss; *t != 0; t++)
2887 if (!isalnum(*t) && *t != '.' && *t != '-' && *t != '_' &&
2888 (!allow_utf8_domains || *t < 128)) break;
2890 /* If the pattern is a complete domain name, with no fancy characters, look up
2891 its IP address and match against that. Note that a multi-homed host will add
2892 items to the chain. */
2903 rc = host_find_byname(&h, NULL, HOST_FIND_QUALIFY_SINGLE, NULL, FALSE);
2904 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2907 for (hh = &h; hh != NULL; hh = hh->next)
2909 if (host_is_in_net(hh->address, cb->host_address, 0)) return OK;
2913 if (rc == HOST_FIND_AGAIN) return DEFER;
2914 *error = string_sprintf("failed to find IP address for %s", ss);
2918 /* Almost all subsequent comparisons require the host name, and can be done
2919 using the general string matching function. When this function is called for
2920 outgoing hosts, the name is always given explicitly. If it is NULL, it means we
2921 must use sender_host_name and its aliases, looking them up if necessary. */
2923 if (cb->host_name != NULL) /* Explicit host name given */
2924 return match_check_string(cb->host_name, ss, -1, TRUE, TRUE, TRUE,
2927 /* Host name not given; in principle we need the sender host name and its
2928 aliases. However, for query-style lookups, we do not need the name if the
2929 query does not contain $sender_host_name. From release 4.23, a reference to
2930 $sender_host_name causes it to be looked up, so we don't need to do the lookup
2933 if ((semicolon = Ustrchr(ss, ';')) != NULL)
2936 int partial, affixlen, starflags, id;
2939 id = search_findtype_partial(ss, &partial, &affix, &affixlen, &starflags);
2942 if (id < 0) /* Unknown lookup type */
2944 log_write(0, LOG_MAIN|LOG_PANIC, "%s in host list item \"%s\"",
2945 search_error_message, ss);
2948 isquery = mac_islookup(id, lookup_querystyle|lookup_absfilequery);
2953 switch(match_check_string(US"", ss, -1, TRUE, TRUE, TRUE, valueptr))
2956 case DEFER: return DEFER;
2957 default: return FAIL;
2961 /* Not a query-style lookup; must ensure the host name is present, and then we
2962 do a check on the name and all its aliases. */
2964 if (sender_host_name == NULL)
2966 HDEBUG(D_host_lookup)
2967 debug_printf("sender host name required, to match against %s\n", ss);
2968 if (host_lookup_failed || host_name_lookup() != OK)
2970 *error = string_sprintf("failed to find host name for %s",
2971 sender_host_address);;
2974 host_build_sender_fullhost();
2977 /* Match on the sender host name, using the general matching function */
2979 switch(match_check_string(sender_host_name, ss, -1, TRUE, TRUE, TRUE,
2983 case DEFER: return DEFER;
2986 /* If there are aliases, try matching on them. */
2988 aliases = sender_host_aliases;
2989 while (*aliases != NULL)
2991 switch(match_check_string(*aliases++, ss, -1, TRUE, TRUE, TRUE, valueptr))
2994 case DEFER: return DEFER;
3003 /*************************************************
3004 * Check a specific host matches a host list *
3005 *************************************************/
3007 /* This function is passed a host list containing items in a number of
3008 different formats and the identity of a host. Its job is to determine whether
3009 the given host is in the set of hosts defined by the list. The host name is
3010 passed as a pointer so that it can be looked up if needed and not already
3011 known. This is commonly the case when called from verify_check_host() to check
3012 an incoming connection. When called from elsewhere the host name should usually
3015 This function is now just a front end to match_check_list(), which runs common
3016 code for scanning a list. We pass it the check_host() function to perform a
3020 listptr pointer to the host list
3021 cache_bits pointer to cache for named lists, or NULL
3022 host_name the host name or NULL, implying use sender_host_name and
3023 sender_host_aliases, looking them up if required
3024 host_address the IP address
3025 valueptr if not NULL, data from a lookup is passed back here
3027 Returns: OK if the host is in the defined set
3028 FAIL if the host is not in the defined set,
3029 DEFER if a data lookup deferred (not a host lookup)
3031 If the host name was needed in order to make a comparison, and could not be
3032 determined from the IP address, the result is FAIL unless the item
3033 "+allow_unknown" was met earlier in the list, in which case OK is returned. */
3036 verify_check_this_host(uschar **listptr, unsigned int *cache_bits,
3037 uschar *host_name, uschar *host_address, uschar **valueptr)
3040 unsigned int *local_cache_bits = cache_bits;
3041 uschar *save_host_address = deliver_host_address;
3042 check_host_block cb;
3043 cb.host_name = host_name;
3044 cb.host_address = host_address;
3046 if (valueptr != NULL) *valueptr = NULL;
3048 /* If the host address starts off ::ffff: it is an IPv6 address in
3049 IPv4-compatible mode. Find the IPv4 part for checking against IPv4
3052 cb.host_ipv4 = (Ustrncmp(host_address, "::ffff:", 7) == 0)?
3053 host_address + 7 : host_address;
3055 /* During the running of the check, put the IP address into $host_address. In
3056 the case of calls from the smtp transport, it will already be there. However,
3057 in other calls (e.g. when testing ignore_target_hosts), it won't. Just to be on
3058 the safe side, any existing setting is preserved, though as I write this
3059 (November 2004) I can't see any cases where it is actually needed. */
3061 deliver_host_address = host_address;
3062 rc = match_check_list(
3063 listptr, /* the list */
3064 0, /* separator character */
3065 &hostlist_anchor, /* anchor pointer */
3066 &local_cache_bits, /* cache pointer */
3067 check_host, /* function for testing */
3068 &cb, /* argument for function */
3069 MCL_HOST, /* type of check */
3070 (host_address == sender_host_address)?
3071 US"host" : host_address, /* text for debugging */
3072 valueptr); /* where to pass back data */
3073 deliver_host_address = save_host_address;
3080 /*************************************************
3081 * Check the remote host matches a list *
3082 *************************************************/
3084 /* This is a front end to verify_check_this_host(), created because checking
3085 the remote host is a common occurrence. With luck, a good compiler will spot
3086 the tail recursion and optimize it. If there's no host address, this is
3087 command-line SMTP input - check against an empty string for the address.
3090 listptr pointer to the host list
3092 Returns: the yield of verify_check_this_host(),
3093 i.e. OK, FAIL, or DEFER
3097 verify_check_host(uschar **listptr)
3099 return verify_check_this_host(listptr, sender_host_cache, NULL,
3100 (sender_host_address == NULL)? US"" : sender_host_address, NULL);
3107 /*************************************************
3108 * Invert an IP address *
3109 *************************************************/
3111 /* Originally just used for DNS xBL lists, now also used for the
3112 reverse_ip expansion operator.
3115 buffer where to put the answer
3116 address the address to invert
3120 invert_address(uschar *buffer, uschar *address)
3123 uschar *bptr = buffer;
3125 /* If this is an IPv4 address mapped into IPv6 format, adjust the pointer
3126 to the IPv4 part only. */
3128 if (Ustrncmp(address, "::ffff:", 7) == 0) address += 7;
3130 /* Handle IPv4 address: when HAVE_IPV6 is false, the result of host_aton() is
3133 if (host_aton(address, bin) == 1)
3137 for (i = 0; i < 4; i++)
3139 sprintf(CS bptr, "%d.", x & 255);
3140 while (*bptr) bptr++;
3145 /* Handle IPv6 address. Actually, as far as I know, there are no IPv6 addresses
3146 in any DNS black lists, and the format in which they will be looked up is
3147 unknown. This is just a guess. */
3153 for (j = 3; j >= 0; j--)
3156 for (i = 0; i < 8; i++)
3158 sprintf(CS bptr, "%x.", x & 15);
3159 while (*bptr) bptr++;
3166 /* Remove trailing period -- this is needed so that both arbitrary
3167 dnsbl keydomains and inverted addresses may be combined with the
3168 same format string, "%s.%s" */
3175 /*************************************************
3176 * Perform a single dnsbl lookup *
3177 *************************************************/
3179 /* This function is called from verify_check_dnsbl() below. It is also called
3180 recursively from within itself when domain and domain_txt are different
3181 pointers, in order to get the TXT record from the alternate domain.
3184 domain the outer dnsbl domain
3185 domain_txt alternate domain to lookup TXT record on success; when the
3186 same domain is to be used, domain_txt == domain (that is,
3187 the pointers must be identical, not just the text)
3188 keydomain the current keydomain (for debug message)
3189 prepend subdomain to lookup (like keydomain, but
3190 reversed if IP address)
3191 iplist the list of matching IP addresses, or NULL for "any"
3192 bitmask true if bitmask matching is wanted
3193 match_type condition for 'succeed' result
3194 0 => Any RR in iplist (=)
3195 1 => No RR in iplist (!=)
3196 2 => All RRs in iplist (==)
3197 3 => Some RRs not in iplist (!==)
3198 the two bits are defined as MT_NOT and MT_ALL
3199 defer_return what to return for a defer
3201 Returns: OK if lookup succeeded
3206 one_check_dnsbl(uschar *domain, uschar *domain_txt, uschar *keydomain,
3207 uschar *prepend, uschar *iplist, BOOL bitmask, int match_type,
3213 dnsbl_cache_block *cb;
3214 int old_pool = store_pool;
3215 uschar query[256]; /* DNS domain max length */
3217 /* Construct the specific query domainname */
3219 if (!string_format(query, sizeof(query), "%s.%s", prepend, domain))
3221 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
3222 "(ignored): %s...", query);
3226 /* Look for this query in the cache. */
3228 t = tree_search(dnsbl_cache, query);
3230 /* If not cached from a previous lookup, we must do a DNS lookup, and
3231 cache the result in permanent memory. */
3235 store_pool = POOL_PERM;
3237 /* Set up a tree entry to cache the lookup */
3239 t = store_get(sizeof(tree_node) + Ustrlen(query));
3240 Ustrcpy(t->name, query);
3241 t->data.ptr = cb = store_get(sizeof(dnsbl_cache_block));
3242 (void)tree_insertnode(&dnsbl_cache, t);
3244 /* Do the DNS loopup . */
3246 HDEBUG(D_dnsbl) debug_printf("new DNS lookup for %s\n", query);
3247 cb->rc = dns_basic_lookup(&dnsa, query, T_A);
3248 cb->text_set = FALSE;
3252 /* If the lookup succeeded, cache the RHS address. The code allows for
3253 more than one address - this was for complete generality and the possible
3254 use of A6 records. However, A6 records have been reduced to experimental
3255 status (August 2001) and may die out. So they may never get used at all,
3256 let alone in dnsbl records. However, leave the code here, just in case.
3258 Quite apart from one A6 RR generating multiple addresses, there are DNS
3259 lists that return more than one A record, so we must handle multiple
3260 addresses generated in that way as well. */
3262 if (cb->rc == DNS_SUCCEED)
3265 dns_address **addrp = &(cb->rhs);
3266 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
3268 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3270 if (rr->type == T_A)
3272 dns_address *da = dns_address_from_rr(&dnsa, rr);
3276 while (da->next != NULL) da = da->next;
3277 addrp = &(da->next);
3282 /* If we didn't find any A records, change the return code. This can
3283 happen when there is a CNAME record but there are no A records for what
3286 if (cb->rhs == NULL) cb->rc = DNS_NODATA;
3289 store_pool = old_pool;
3292 /* Previous lookup was cached */
3296 HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
3300 /* We now have the result of the DNS lookup, either newly done, or cached
3301 from a previous call. If the lookup succeeded, check against the address
3302 list if there is one. This may be a positive equality list (introduced by
3303 "="), a negative equality list (introduced by "!="), a positive bitmask
3304 list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/
3306 if (cb->rc == DNS_SUCCEED)
3308 dns_address *da = NULL;
3309 uschar *addlist = cb->rhs->address;
3311 /* For A and AAAA records, there may be multiple addresses from multiple
3312 records. For A6 records (currently not expected to be used) there may be
3313 multiple addresses from a single record. */
3315 for (da = cb->rhs->next; da != NULL; da = da->next)
3316 addlist = string_sprintf("%s, %s", addlist, da->address);
3318 HDEBUG(D_dnsbl) debug_printf("DNS lookup for %s succeeded (yielding %s)\n",
3321 /* Address list check; this can be either for equality, or via a bitmask.
3322 In the latter case, all the bits must match. */
3326 for (da = cb->rhs; da != NULL; da = da->next)
3330 uschar *ptr = iplist;
3333 /* Handle exact matching */
3337 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))) != NULL)
3339 if (Ustrcmp(CS da->address, ip) == 0) break;
3343 /* Handle bitmask matching */
3350 /* At present, all known DNS blocking lists use A records, with
3351 IPv4 addresses on the RHS encoding the information they return. I
3352 wonder if this will linger on as the last vestige of IPv4 when IPv6
3353 is ubiquitous? Anyway, for now we use paranoia code to completely
3354 ignore IPv6 addresses. The default mask is 0, which always matches.
3355 We change this only for IPv4 addresses in the list. */
3357 if (host_aton(da->address, address) == 1) mask = address[0];
3359 /* Scan the returned addresses, skipping any that are IPv6 */
3361 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))) != NULL)
3363 if (host_aton(ip, address) != 1) continue;
3364 if ((address[0] & mask) == address[0]) break;
3370 (a) An IP address in an any ('=') list matched, or
3371 (b) No IP address in an all ('==') list matched
3373 then we're done searching. */
3375 if (((match_type & MT_ALL) != 0) == (res == NULL)) break;
3378 /* If da == NULL, either
3380 (a) No IP address in an any ('=') list matched, or
3381 (b) An IP address in an all ('==') list didn't match
3383 so behave as if the DNSBL lookup had not succeeded, i.e. the host is not on
3386 if ((match_type == MT_NOT || match_type == MT_ALL) != (da == NULL))
3394 res = US"was no match";
3397 res = US"was an exclude match";
3400 res = US"was an IP address that did not match";
3403 res = US"were no IP addresses that did not match";
3406 debug_printf("=> but we are not accepting this block class because\n");
3407 debug_printf("=> there %s for %s%c%s\n",
3409 ((match_type & MT_ALL) == 0)? "" : "=",
3410 bitmask? '&' : '=', iplist);
3416 /* Either there was no IP list, or the record matched, implying that the
3417 domain is on the list. We now want to find a corresponding TXT record. If an
3418 alternate domain is specified for the TXT record, call this function
3419 recursively to look that up; this has the side effect of re-checking that
3420 there is indeed an A record at the alternate domain. */
3422 if (domain_txt != domain)
3423 return one_check_dnsbl(domain_txt, domain_txt, keydomain, prepend, NULL,
3424 FALSE, match_type, defer_return);
3426 /* If there is no alternate domain, look up a TXT record in the main domain
3427 if it has not previously been cached. */
3431 cb->text_set = TRUE;
3432 if (dns_basic_lookup(&dnsa, query, T_TXT) == DNS_SUCCEED)
3435 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
3437 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3438 if (rr->type == T_TXT) break;
3441 int len = (rr->data)[0];
3442 if (len > 511) len = 127;
3443 store_pool = POOL_PERM;
3444 cb->text = string_sprintf("%.*s", len, (const uschar *)(rr->data+1));
3445 store_pool = old_pool;
3450 dnslist_value = addlist;
3451 dnslist_text = cb->text;
3455 /* There was a problem with the DNS lookup */
3457 if (cb->rc != DNS_NOMATCH && cb->rc != DNS_NODATA)
3459 log_write(L_dnslist_defer, LOG_MAIN,
3460 "DNS list lookup defer (probably timeout) for %s: %s", query,
3461 (defer_return == OK)? US"assumed in list" :
3462 (defer_return == FAIL)? US"assumed not in list" :
3463 US"returned DEFER");
3464 return defer_return;
3467 /* No entry was found in the DNS; continue for next domain */
3471 debug_printf("DNS lookup for %s failed\n", query);
3472 debug_printf("=> that means %s is not listed at %s\n",
3482 /*************************************************
3483 * Check host against DNS black lists *
3484 *************************************************/
3486 /* This function runs checks against a list of DNS black lists, until one
3487 matches. Each item on the list can be of the form
3489 domain=ip-address/key
3491 The domain is the right-most domain that is used for the query, for example,
3492 blackholes.mail-abuse.org. If the IP address is present, there is a match only
3493 if the DNS lookup returns a matching IP address. Several addresses may be
3494 given, comma-separated, for example: x.y.z=127.0.0.1,127.0.0.2.
3496 If no key is given, what is looked up in the domain is the inverted IP address
3497 of the current client host. If a key is given, it is used to construct the
3498 domain for the lookup. For example:
3500 dsn.rfc-ignorant.org/$sender_address_domain
3502 After finding a match in the DNS, the domain is placed in $dnslist_domain, and
3503 then we check for a TXT record for an error message, and if found, save its
3504 value in $dnslist_text. We also cache everything in a tree, to optimize
3507 The TXT record is normally looked up in the same domain as the A record, but
3508 when many lists are combined in a single DNS domain, this will not be a very
3509 specific message. It is possible to specify a different domain for looking up
3510 TXT records; this is given before the main domain, comma-separated. For
3513 dnslists = http.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.2 : \
3514 socks.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.3
3516 The caching ensures that only one lookup in dnsbl.sorbs.net is done.
3518 Note: an address for testing RBL is 192.203.178.39
3519 Note: an address for testing DUL is 192.203.178.4
3520 Note: a domain for testing RFCI is example.tld.dsn.rfc-ignorant.org
3523 listptr the domain/address/data list
3525 Returns: OK successful lookup (i.e. the address is on the list), or
3526 lookup deferred after +include_unknown
3527 FAIL name not found, or no data found for the given type, or
3528 lookup deferred after +exclude_unknown (default)
3529 DEFER lookup failure, if +defer_unknown was set
3533 verify_check_dnsbl(uschar **listptr)
3536 int defer_return = FAIL;
3537 uschar *list = *listptr;
3540 uschar buffer[1024];
3541 uschar revadd[128]; /* Long enough for IPv6 address */
3543 /* Indicate that the inverted IP address is not yet set up */
3547 /* In case this is the first time the DNS resolver is being used. */
3549 dns_init(FALSE, FALSE);
3551 /* Loop through all the domains supplied, until something matches */
3553 while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
3556 BOOL bitmask = FALSE;
3563 HDEBUG(D_dnsbl) debug_printf("DNS list check: %s\n", domain);
3565 /* Deal with special values that change the behaviour on defer */
3567 if (domain[0] == '+')
3569 if (strcmpic(domain, US"+include_unknown") == 0) defer_return = OK;
3570 else if (strcmpic(domain, US"+exclude_unknown") == 0) defer_return = FAIL;
3571 else if (strcmpic(domain, US"+defer_unknown") == 0) defer_return = DEFER;
3573 log_write(0, LOG_MAIN|LOG_PANIC, "unknown item in dnslist (ignored): %s",
3578 /* See if there's explicit data to be looked up */
3580 key = Ustrchr(domain, '/');
3581 if (key != NULL) *key++ = 0;
3583 /* See if there's a list of addresses supplied after the domain name. This is
3584 introduced by an = or a & character; if preceded by = we require all matches
3585 and if preceded by ! we invert the result. */
3587 iplist = Ustrchr(domain, '=');
3591 iplist = Ustrchr(domain, '&');
3594 if (iplist != NULL) /* Found either = or & */
3596 if (iplist > domain && iplist[-1] == '!') /* Handle preceding ! */
3598 match_type |= MT_NOT;
3602 *iplist++ = 0; /* Terminate domain, move on */
3604 /* If we found = (bitmask == FALSE), check for == or =& */
3606 if (!bitmask && (*iplist == '=' || *iplist == '&'))
3608 bitmask = *iplist++ == '&';
3609 match_type |= MT_ALL;
3613 /* If there is a comma in the domain, it indicates that a second domain for
3614 looking up TXT records is provided, before the main domain. Otherwise we must
3615 set domain_txt == domain. */
3617 domain_txt = domain;
3618 comma = Ustrchr(domain, ',');
3625 /* Check that what we have left is a sensible domain name. There is no reason
3626 why these domains should in fact use the same syntax as hosts and email
3627 domains, but in practice they seem to. However, there is little point in
3628 actually causing an error here, because that would no doubt hold up incoming
3629 mail. Instead, I'll just log it. */
3631 for (s = domain; *s != 0; s++)
3633 if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_')
3635 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
3636 "strange characters - is this right?", domain);
3641 /* Check the alternate domain if present */
3643 if (domain_txt != domain) for (s = domain_txt; *s != 0; s++)
3645 if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_')
3647 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
3648 "strange characters - is this right?", domain_txt);
3653 /* If there is no key string, construct the query by adding the domain name
3654 onto the inverted host address, and perform a single DNS lookup. */
3658 if (sender_host_address == NULL) return FAIL; /* can never match */
3659 if (revadd[0] == 0) invert_address(revadd, sender_host_address);
3660 rc = one_check_dnsbl(domain, domain_txt, sender_host_address, revadd,
3661 iplist, bitmask, match_type, defer_return);
3664 dnslist_domain = string_copy(domain_txt);
3665 dnslist_matched = string_copy(sender_host_address);
3666 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
3667 sender_host_address, dnslist_domain);
3669 if (rc != FAIL) return rc; /* OK or DEFER */
3672 /* If there is a key string, it can be a list of domains or IP addresses to
3673 be concatenated with the main domain. */
3680 uschar keybuffer[256];
3681 uschar keyrevadd[128];
3683 while ((keydomain = string_nextinlist(&key, &keysep, keybuffer,
3684 sizeof(keybuffer))) != NULL)
3686 uschar *prepend = keydomain;
3688 if (string_is_ip_address(keydomain, NULL) != 0)
3690 invert_address(keyrevadd, keydomain);
3691 prepend = keyrevadd;
3694 rc = one_check_dnsbl(domain, domain_txt, keydomain, prepend, iplist,
3695 bitmask, match_type, defer_return);
3699 dnslist_domain = string_copy(domain_txt);
3700 dnslist_matched = string_copy(keydomain);
3701 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
3702 keydomain, dnslist_domain);
3706 /* If the lookup deferred, remember this fact. We keep trying the rest
3707 of the list to see if we get a useful result, and if we don't, we return
3708 DEFER at the end. */
3710 if (rc == DEFER) defer = TRUE;
3711 } /* continue with next keystring domain/address */
3713 if (defer) return DEFER;
3715 } /* continue with next dnsdb outer domain */
3722 /* End of verify.c */