1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2014 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions concerned with verifying things. The original code for callout
9 caching was contributed by Kevin Fleming (but I hacked it around a bit). */
13 #include "transports/smtp.h"
15 #define CUTTHROUGH_CMD_TIMEOUT 30 /* timeout for cutthrough-routing calls */
16 #define CUTTHROUGH_DATA_TIMEOUT 60 /* timeout for cutthrough-routing calls */
17 static smtp_outblock ctblock;
18 uschar ctbuffer[8192];
21 /* Structure for caching DNSBL lookups */
23 typedef struct dnsbl_cache_block {
31 /* Anchor for DNSBL cache */
33 static tree_node *dnsbl_cache = NULL;
36 /* Bits for match_type in one_check_dnsbl() */
41 static uschar cutthrough_response(char, uschar **);
44 /*************************************************
45 * Retrieve a callout cache record *
46 *************************************************/
48 /* If a record exists, check whether it has expired.
51 dbm_file an open hints file
53 type "address" or "domain"
54 positive_expire expire time for positive records
55 negative_expire expire time for negative records
57 Returns: the cache record if a non-expired one exists, else NULL
60 static dbdata_callout_cache *
61 get_callout_cache_record(open_db *dbm_file, 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)
194 address_key = string_sprintf("%s/<%s>", addr->address, sender_address);
195 from_address = sender_address;
197 else if (options & vopt_callout_recippmaster)
199 address_key = string_sprintf("%s/<postmaster@%s>", addr->address,
200 qualify_domain_sender);
201 from_address = string_sprintf("postmaster@%s", qualify_domain_sender);
205 /* For a sender callout, we must adjust the key if the mailfrom address is not
210 from_address = (se_mailfrom == NULL)? US"" : se_mailfrom;
211 if (from_address[0] != 0)
212 address_key = string_sprintf("%s/<%s>", addr->address, from_address);
215 /* Open the callout cache database, it it exists, for reading only at this
216 stage, unless caching has been disabled. */
218 if (callout_no_cache)
220 HDEBUG(D_verify) debug_printf("callout cache: disabled by no_cache\n");
222 else if ((dbm_file = dbfn_open(US"callout", O_RDWR, &dbblock, FALSE)) == NULL)
224 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
227 /* If a cache database is available see if we can avoid the need to do an
228 actual callout by making use of previously-obtained data. */
230 if (dbm_file != NULL)
232 dbdata_callout_cache_address *cache_address_record;
233 dbdata_callout_cache *cache_record = get_callout_cache_record(dbm_file,
234 addr->domain, US"domain",
235 callout_cache_domain_positive_expire,
236 callout_cache_domain_negative_expire);
238 /* If an unexpired cache record was found for this domain, see if the callout
239 process can be short-circuited. */
241 if (cache_record != NULL)
243 /* In most cases, if an early command (up to and including MAIL FROM:<>)
244 was rejected, there is no point carrying on. The callout fails. However, if
245 we are doing a recipient verification with use_sender or use_postmaster
246 set, a previous failure of MAIL FROM:<> doesn't count, because this time we
247 will be using a non-empty sender. We have to remember this situation so as
248 not to disturb the cached domain value if this whole verification succeeds
249 (we don't want it turning into "accept"). */
251 old_domain_cache_result = cache_record->result;
253 if (cache_record->result == ccache_reject ||
254 (*from_address == 0 && cache_record->result == ccache_reject_mfnull))
256 setflag(addr, af_verify_nsfail);
258 debug_printf("callout cache: domain gave initial rejection, or "
259 "does not accept HELO or MAIL FROM:<>\n");
260 setflag(addr, af_verify_nsfail);
261 addr->user_message = US"(result of an earlier callout reused).";
263 *failure_ptr = US"mail";
267 /* If a previous check on a "random" local part was accepted, we assume
268 that the server does not do any checking on local parts. There is therefore
269 no point in doing the callout, because it will always be successful. If a
270 random check previously failed, arrange not to do it again, but preserve
271 the data in the new record. If a random check is required but hasn't been
272 done, skip the remaining cache processing. */
274 if (callout_random) switch(cache_record->random_result)
278 debug_printf("callout cache: domain accepts random addresses\n");
279 goto END_CALLOUT; /* Default yield is OK */
283 debug_printf("callout cache: domain rejects random addresses\n");
284 callout_random = FALSE;
285 new_domain_record.random_result = ccache_reject;
286 new_domain_record.random_stamp = cache_record->random_stamp;
291 debug_printf("callout cache: need to check random address handling "
292 "(not cached or cache expired)\n");
296 /* If a postmaster check is requested, but there was a previous failure,
297 there is again no point in carrying on. If a postmaster check is required,
298 but has not been done before, we are going to have to do a callout, so skip
299 remaining cache processing. */
301 if (pm_mailfrom != NULL)
303 if (cache_record->postmaster_result == ccache_reject)
305 setflag(addr, af_verify_pmfail);
307 debug_printf("callout cache: domain does not accept "
308 "RCPT TO:<postmaster@domain>\n");
310 *failure_ptr = US"postmaster";
311 setflag(addr, af_verify_pmfail);
312 addr->user_message = US"(result of earlier verification reused).";
315 if (cache_record->postmaster_result == ccache_unknown)
318 debug_printf("callout cache: need to check RCPT "
319 "TO:<postmaster@domain> (not cached or cache expired)\n");
323 /* If cache says OK, set pm_mailfrom NULL to prevent a redundant
324 postmaster check if the address itself has to be checked. Also ensure
325 that the value in the cache record is preserved (with its old timestamp).
328 HDEBUG(D_verify) debug_printf("callout cache: domain accepts RCPT "
329 "TO:<postmaster@domain>\n");
331 new_domain_record.postmaster_result = ccache_accept;
332 new_domain_record.postmaster_stamp = cache_record->postmaster_stamp;
336 /* We can't give a result based on information about the domain. See if there
337 is an unexpired cache record for this specific address (combined with the
338 sender address if we are doing a recipient callout with a non-empty sender).
341 cache_address_record = (dbdata_callout_cache_address *)
342 get_callout_cache_record(dbm_file,
343 address_key, US"address",
344 callout_cache_positive_expire,
345 callout_cache_negative_expire);
347 if (cache_address_record != NULL)
349 if (cache_address_record->result == ccache_accept)
352 debug_printf("callout cache: address record is positive\n");
357 debug_printf("callout cache: address record is negative\n");
358 addr->user_message = US"Previous (cached) callout verification failure";
359 *failure_ptr = US"recipient";
365 /* Close the cache database while we actually do the callout for real. */
368 dbfn_close(dbm_file);
372 if (!addr->transport)
374 HDEBUG(D_verify) debug_printf("cannot callout via null transport\n");
376 else if (Ustrcmp(addr->transport->driver_name, "smtp") != 0)
377 log_write(0, LOG_MAIN|LOG_PANIC|LOG_CONFIG_FOR, "callout transport '%s': %s is non-smtp",
378 addr->transport->name, addr->transport->driver_name);
381 smtp_transport_options_block *ob =
382 (smtp_transport_options_block *)addr->transport->options_block;
384 /* The information wasn't available in the cache, so we have to do a real
385 callout and save the result in the cache for next time, unless no_cache is set,
386 or unless we have a previously cached negative random result. If we are to test
387 with a random local part, ensure that such a local part is available. If not,
388 log the fact, but carry on without randomming. */
390 if (callout_random && callout_random_local_part != NULL)
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 /* cutthrough-multi: if a nonfirst rcpt has the same routing as the first,
414 and we are holding a cutthrough conn open, we can just append the rcpt to
415 that conn for verification purposes (and later delivery also). Simplest
416 coding means skipping this whole loop and doing the append separately.
418 We will need to remember it has been appended so that rcpt-acl tail code
419 can do it there for the non-rcpt-verify case. For this we keep an addresscount.
422 /* Can we re-use an open cutthrough connection? */
423 if ( cutthrough.fd >= 0
424 && (options & (vopt_callout_recipsender | vopt_callout_recippmaster))
425 == vopt_callout_recipsender
426 && !random_local_part
430 if (addr->transport == cutthrough.addr.transport)
431 for (host = host_list; host; host = host->next)
432 if (Ustrcmp(host->address, cutthrough.host.address) == 0)
435 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
438 deliver_host = host->name;
439 deliver_host_address = host->address;
440 deliver_host_port = host->port;
441 deliver_domain = addr->domain;
442 transport_name = addr->transport->name;
444 host_af = (Ustrchr(host->address, ':') == NULL)? AF_INET:AF_INET6;
446 if (!smtp_get_interface(tf->interface, host_af, addr, NULL, &interface,
448 !smtp_get_port(tf->port, addr, &port, US"callout"))
449 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
452 if ( ( interface == cutthrough.interface
454 && cutthrough.interface
455 && Ustrcmp(interface, cutthrough.interface) == 0
457 && port == cutthrough.host.port
462 /* Match! Send the RCPT TO, append the addr, set done */
464 smtp_write_command(&ctblock, FALSE, "RCPT TO:<%.1000s>\r\n",
465 transport_rcpt_address(addr,
466 (addr->transport == NULL)? FALSE :
467 addr->transport->rcpt_include_affixes)) >= 0 &&
468 cutthrough_response('2', &resp) == '2';
470 /* This would go horribly wrong if a callout fail was ignored by ACL.
471 We punt by abandoning cutthrough on a reject, like the
476 address_item * na = store_get(sizeof(address_item));
477 *na = cutthrough.addr;
478 cutthrough.addr = *addr;
479 cutthrough.addr.host_used = &cutthrough.host;
480 cutthrough.addr.next = na;
486 cancel_cutthrough_connection("recipient rejected");
487 if (errno == ETIMEDOUT)
489 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
494 Ustrcpy(resp, US"connection dropped");
497 string_sprintf("response to \"%s\" from %s [%s] was: %s",
498 big_buffer, host->name, host->address,
499 string_printing(resp));
502 string_sprintf("Callout verification failed:\n%s", resp);
504 /* Hard rejection ends the process */
506 if (resp[0] == '5') /* Address rejected */
517 cancel_cutthrough_connection("incompatible connection");
520 /* Now make connections to the hosts and do real callouts. The list of hosts
521 is passed in as an argument. */
523 for (host = host_list; host != NULL && !done; host = host->next)
525 smtp_inblock inblock;
526 smtp_outblock outblock;
529 BOOL send_quit = TRUE;
530 uschar *active_hostname = smtp_active_hostname;
534 BOOL suppress_tls = FALSE;
535 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
536 #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_DANE)
538 dns_answer tlsa_dnsa;
540 uschar inbuffer[4096];
541 uschar outbuffer[1024];
542 uschar responsebuffer[4096];
544 clearflag(addr, af_verify_pmfail); /* postmaster callout flag */
545 clearflag(addr, af_verify_nsfail); /* null sender callout flag */
547 /* Skip this host if we don't have an IP address for it. */
549 if (host->address == NULL)
551 DEBUG(D_verify) debug_printf("no IP address for host name %s: skipping\n",
556 /* Check the overall callout timeout */
558 if (time(NULL) - callout_start_time >= callout_overall)
560 HDEBUG(D_verify) debug_printf("overall timeout for callout exceeded\n");
564 /* Set IPv4 or IPv6 */
566 host_af = (Ustrchr(host->address, ':') == NULL)? AF_INET:AF_INET6;
568 /* Expand and interpret the interface and port strings. The latter will not
569 be used if there is a host-specific port (e.g. from a manualroute router).
570 This has to be delayed till now, because they may expand differently for
571 different hosts. If there's a failure, log it, but carry on with the
574 deliver_host = host->name;
575 deliver_host_address = host->address;
576 deliver_host_port = host->port;
577 deliver_domain = addr->domain;
578 transport_name = addr->transport->name;
580 if (!smtp_get_interface(tf->interface, host_af, addr, NULL, &interface,
582 !smtp_get_port(tf->port, addr, &port, US"callout"))
583 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
586 /* Set HELO string according to the protocol */
587 lmtp= Ustrcmp(tf->protocol, "lmtp") == 0;
588 smtps= Ustrcmp(tf->protocol, "smtps") == 0;
591 HDEBUG(D_verify) debug_printf("interface=%s port=%d\n", interface, port);
593 #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_DANE)
598 tls_out.dane_verified = FALSE;
599 tls_out.tlsa_usage = 0;
602 verify_check_given_host(&ob->hosts_require_dane, host) == OK;
604 if (host->dnssec == DS_YES)
607 || verify_check_given_host(&ob->hosts_try_dane, host) == OK
609 if ((rc = tlsa_lookup(host, &tlsa_dnsa, dane_required, &dane)) != OK)
612 else if (dane_required)
614 log_write(0, LOG_MAIN, "DANE error: %s lookup not DNSSEC", host->name);
619 ob->tls_tempfail_tryclear = FALSE;
623 /* Set up the buffer for reading SMTP response packets. */
625 inblock.buffer = inbuffer;
626 inblock.buffersize = sizeof(inbuffer);
627 inblock.ptr = inbuffer;
628 inblock.ptrend = inbuffer;
630 /* Set up the buffer for holding SMTP commands while pipelining */
632 outblock.buffer = outbuffer;
633 outblock.buffersize = sizeof(outbuffer);
634 outblock.ptr = outbuffer;
635 outblock.cmd_count = 0;
636 outblock.authenticating = FALSE;
638 /* Reset the parameters of a TLS session */
639 tls_out.cipher = tls_out.peerdn = NULL;
641 /* Connect to the host; on failure, just loop for the next one, but we
642 set the error for the last one. Use the callout_connect timeout. */
644 tls_retry_connection:
646 inblock.sock = outblock.sock =
647 smtp_connect(host, host_af, port, interface, callout_connect, TRUE, NULL
648 #ifdef EXPERIMENTAL_EVENT
649 /*XXX event action? NULL for now. */
653 /* reconsider DSCP here */
654 if (inblock.sock < 0)
656 addr->message = string_sprintf("could not connect to %s [%s]: %s",
657 host->name, host->address, strerror(errno));
658 transport_name = NULL;
659 deliver_host = deliver_host_address = NULL;
660 deliver_domain = save_deliver_domain;
664 /* Expand the helo_data string to find the host name to use. */
666 if (tf->helo_data != NULL)
668 uschar *s = expand_string(tf->helo_data);
670 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: failed to expand transport's "
671 "helo_data value for callout: %s", addr->address,
672 expand_string_message);
673 else active_hostname = s;
676 /* Wait for initial response, and send HELO. The smtp_write_command()
677 function leaves its command in big_buffer. This is used in error responses.
678 Initialize it in case the connection is rejected. */
680 Ustrcpy(big_buffer, "initial connection");
682 /* Unless ssl-on-connect, wait for the initial greeting */
686 if (!smtps || (smtps && tls_out.active >= 0))
689 if (!(done= smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), '2', callout)))
690 goto RESPONSE_FAILED;
692 #ifdef EXPERIMENTAL_EVENT
693 lookup_dnssec_authenticated = host->dnssec==DS_YES ? US"yes"
694 : host->dnssec==DS_NO ? US"no" : NULL;
695 if (event_raise(addr->transport->event_action,
696 US"smtp:connect", responsebuffer))
698 lookup_dnssec_authenticated = NULL;
699 /* Logging? Debug? */
700 goto RESPONSE_FAILED;
702 lookup_dnssec_authenticated = NULL;
706 /* Not worth checking greeting line for ESMTP support */
707 if (!(esmtp = verify_check_given_host(&(ob->hosts_avoid_esmtp), host) != OK))
709 debug_printf("not sending EHLO (host matches hosts_avoid_esmtp)\n");
714 if (smtps && tls_out.active < 0) /* ssl-on-connect, first pass */
717 ob->tls_tempfail_tryclear = FALSE;
719 else /* all other cases */
724 if (!(done= smtp_write_command(&outblock, FALSE, "%s %s\r\n",
725 !esmtp? "HELO" : lmtp? "LHLO" : "EHLO", active_hostname) >= 0))
727 if (!smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), '2', callout))
729 if (errno != 0 || responsebuffer[0] == 0 || lmtp || !esmtp || tls_out.active >= 0)
732 goto RESPONSE_FAILED;
738 goto esmtp_retry; /* fallback to HELO */
741 /* Set tls_offered if the response to EHLO specifies support for STARTTLS. */
743 if (esmtp && !suppress_tls && tls_out.active < 0)
745 if (regex_STARTTLS == NULL) regex_STARTTLS =
746 regex_must_compile(US"\\n250[\\s\\-]STARTTLS(\\s|\\n|$)", FALSE, TRUE);
748 tls_offered = pcre_exec(regex_STARTTLS, NULL, CS responsebuffer,
749 Ustrlen(responsebuffer), 0, PCRE_EOPT, NULL, 0) >= 0;
756 /* If TLS is available on this connection attempt to
757 start up a TLS session, unless the host is in hosts_avoid_tls. If successful,
758 send another EHLO - the server may give a different answer in secure mode. We
759 use a separate buffer for reading the response to STARTTLS so that if it is
760 negative, the original EHLO data is available for subsequent analysis, should
761 the client not be required to use TLS. If the response is bad, copy the buffer
762 for error analysis. */
766 && verify_check_given_host(&ob->hosts_avoid_tls, host) != OK
767 && verify_check_given_host(&ob->hosts_verify_avoid_tls, host) != OK
770 uschar buffer2[4096];
772 && !(done= smtp_write_command(&outblock, FALSE, "STARTTLS\r\n") >= 0))
775 /* If there is an I/O error, transmission of this message is deferred. If
776 there is a temporary rejection of STARRTLS and tls_tempfail_tryclear is
777 false, we also defer. However, if there is a temporary rejection of STARTTLS
778 and tls_tempfail_tryclear is true, or if there is an outright rejection of
779 STARTTLS, we carry on. This means we will try to send the message in clear,
780 unless the host is in hosts_require_tls (tested below). */
782 if (!smtps && !smtp_read_response(&inblock, buffer2, sizeof(buffer2), '2',
783 ob->command_timeout))
785 if (errno != 0 || buffer2[0] == 0 ||
786 (buffer2[0] == '4' && !ob->tls_tempfail_tryclear))
788 Ustrncpy(responsebuffer, buffer2, sizeof(responsebuffer));
790 goto RESPONSE_FAILED;
794 /* STARTTLS accepted or ssl-on-connect: try to negotiate a TLS session. */
797 int oldtimeout = ob->command_timeout;
800 ob->command_timeout = callout;
801 rc = tls_client_start(inblock.sock, host, addr, addr->transport
802 # ifdef EXPERIMENTAL_DANE
803 , dane ? &tlsa_dnsa : NULL
806 ob->command_timeout = oldtimeout;
808 /* TLS negotiation failed; give an error. Try in clear on a new connection,
809 if the options permit it for this host. */
813 && ob->tls_tempfail_tryclear
815 && verify_check_given_host(&ob->hosts_require_tls, host) != OK
818 (void)close(inblock.sock);
819 # ifdef EXPERIMENTAL_EVENT
820 (void) event_raise(addr->transport->event_action,
821 US"tcp:close", NULL);
823 log_write(0, LOG_MAIN, "TLS session failure: delivering unencrypted "
824 "to %s [%s] (not in hosts_require_tls)", host->name, host->address);
826 goto tls_retry_connection;
828 /*save_errno = ERRNO_TLSFAILURE;*/
829 /*message = US"failure while setting up TLS session";*/
835 /* TLS session is set up. Copy info for logging. */
836 addr->cipher = tls_out.cipher;
837 addr->peerdn = tls_out.peerdn;
839 /* For SMTPS we need to wait for the initial OK response, then do HELO. */
841 goto smtps_redo_greeting;
843 /* For STARTTLS we need to redo EHLO */
848 /* If the host is required to use a secure channel, ensure that we have one. */
849 if (tls_out.active < 0)
851 # ifdef EXPERIMENTAL_DANE
854 verify_check_given_host(&ob->hosts_require_tls, host) == OK
857 /*save_errno = ERRNO_TLSREQUIRED;*/
858 log_write(0, LOG_MAIN,
859 "H=%s [%s]: a TLS session is required for this host, but %s",
860 host->name, host->address,
861 tls_offered ? "an attempt to start TLS failed"
862 : "the server did not offer TLS support");
867 #endif /*SUPPORT_TLS*/
869 done = TRUE; /* so far so good; have response to HELO */
871 /*XXX the EHLO response would be analyzed here for IGNOREQUOTA, SIZE, PIPELINING */
873 /* For now, transport_filter by cutthrough-delivery is not supported */
874 /* Need proper integration with the proper transport mechanism. */
875 if (cutthrough.delivery)
877 if (addr->transport->filter_command)
879 cutthrough.delivery = FALSE;
880 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of transport filter\n");
885 cutthrough.delivery = FALSE;
886 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of DKIM signing\n");
895 /* Clear down of the TLS, SMTP and TCP layers on error is handled below. */
897 /* Failure to accept HELO is cached; this blocks the whole domain for all
898 senders. I/O errors and defer responses are not cached. */
902 *failure_ptr = US"mail"; /* At or before MAIL */
903 if (errno == 0 && responsebuffer[0] == '5')
905 setflag(addr, af_verify_nsfail);
906 new_domain_record.result = ccache_reject;
910 /* If we haven't authenticated, but are required to, give up. */
913 else done = smtp_auth(responsebuffer, sizeof(responsebuffer),
914 addr, host, ob, esmtp, &inblock, &outblock) == OK &&
916 /* Copy AUTH info for logging */
917 ( (addr->authenticator = client_authenticator),
918 (addr->auth_id = client_authenticated_id),
920 /* Build a mail-AUTH string (re-using responsebuffer for convenience */
921 !smtp_mail_auth_str(responsebuffer, sizeof(responsebuffer), addr, ob)
924 ( (addr->auth_sndr = client_authenticated_sender),
926 /* Send the MAIL command */
927 (smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>%s\r\n",
928 from_address, responsebuffer) >= 0)
931 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
934 deliver_host = deliver_host_address = NULL;
935 deliver_domain = save_deliver_domain;
937 /* If the host does not accept MAIL FROM:<>, arrange to cache this
938 information, but again, don't record anything for an I/O error or a defer. Do
939 not cache rejections of MAIL when a non-empty sender has been used, because
940 that blocks the whole domain for all senders. */
944 *failure_ptr = US"mail"; /* At or before MAIL */
945 if (errno == 0 && responsebuffer[0] == '5')
947 setflag(addr, af_verify_nsfail);
948 if (from_address[0] == 0)
949 new_domain_record.result = ccache_reject_mfnull;
953 /* Otherwise, proceed to check a "random" address (if required), then the
954 given address, and the postmaster address (if required). Between each check,
955 issue RSET, because some servers accept only one recipient after MAIL
958 Before doing this, set the result in the domain cache record to "accept",
959 unless its previous value was ccache_reject_mfnull. In that case, the domain
960 rejects MAIL FROM:<> and we want to continue to remember that. When that is
961 the case, we have got here only in the case of a recipient verification with
962 a non-null sender. */
966 new_domain_record.result =
967 (old_domain_cache_result == ccache_reject_mfnull)?
968 ccache_reject_mfnull: ccache_accept;
970 /* Do the random local part check first */
972 if (random_local_part != NULL)
974 uschar randombuffer[1024];
976 smtp_write_command(&outblock, FALSE,
977 "RCPT TO:<%.1000s@%.1000s>\r\n", random_local_part,
978 addr->domain) >= 0 &&
979 smtp_read_response(&inblock, randombuffer,
980 sizeof(randombuffer), '2', callout);
982 /* Remember when we last did a random test */
984 new_domain_record.random_stamp = time(NULL);
986 /* If accepted, we aren't going to do any further tests below. */
989 new_domain_record.random_result = ccache_accept;
991 /* Otherwise, cache a real negative response, and get back to the right
992 state to send RCPT. Unless there's some problem such as a dropped
993 connection, we expect to succeed, because the commands succeeded above. */
997 cancel_cutthrough_connection("random-recipient");
999 if (randombuffer[0] == '5')
1000 new_domain_record.random_result = ccache_reject;
1003 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
1004 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
1007 smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>\r\n",
1008 from_address) >= 0 &&
1009 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
1012 else done = FALSE; /* Some timeout/connection problem */
1013 } /* Random check */
1015 /* If the host is accepting all local parts, as determined by the "random"
1016 check, we don't need to waste time doing any further checking. */
1018 if (new_domain_record.random_result != ccache_accept && done)
1020 /* Get the rcpt_include_affixes flag from the transport if there is one,
1021 but assume FALSE if there is not. */
1024 smtp_write_command(&outblock, FALSE, "RCPT TO:<%.1000s>\r\n",
1025 transport_rcpt_address(addr,
1026 (addr->transport == NULL)? FALSE :
1027 addr->transport->rcpt_include_affixes)) >= 0 &&
1028 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
1032 new_address_record.result = ccache_accept;
1033 else if (errno == 0 && responsebuffer[0] == '5')
1035 *failure_ptr = US"recipient";
1036 new_address_record.result = ccache_reject;
1039 /* Do postmaster check if requested; if a full check is required, we
1040 check for RCPT TO:<postmaster> (no domain) in accordance with RFC 821. */
1042 if (done && pm_mailfrom != NULL)
1044 /*XXX not suitable for cutthrough - we cannot afford to do an RSET
1045 and lose the original mail-from */
1046 cancel_cutthrough_connection("postmaster verify");
1047 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of postmaster verify\n");
1050 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
1051 smtp_read_response(&inblock, responsebuffer,
1052 sizeof(responsebuffer), '2', callout) &&
1054 smtp_write_command(&outblock, FALSE,
1055 "MAIL FROM:<%s>\r\n", pm_mailfrom) >= 0 &&
1056 smtp_read_response(&inblock, responsebuffer,
1057 sizeof(responsebuffer), '2', callout) &&
1059 /* First try using the current domain */
1062 smtp_write_command(&outblock, FALSE,
1063 "RCPT TO:<postmaster@%.1000s>\r\n", addr->domain) >= 0 &&
1064 smtp_read_response(&inblock, responsebuffer,
1065 sizeof(responsebuffer), '2', callout)
1070 /* If that doesn't work, and a full check is requested,
1071 try without the domain. */
1074 (options & vopt_callout_fullpm) != 0 &&
1075 smtp_write_command(&outblock, FALSE,
1076 "RCPT TO:<postmaster>\r\n") >= 0 &&
1077 smtp_read_response(&inblock, responsebuffer,
1078 sizeof(responsebuffer), '2', callout)
1081 /* Sort out the cache record */
1083 new_domain_record.postmaster_stamp = time(NULL);
1086 new_domain_record.postmaster_result = ccache_accept;
1087 else if (errno == 0 && responsebuffer[0] == '5')
1089 *failure_ptr = US"postmaster";
1090 setflag(addr, af_verify_pmfail);
1091 new_domain_record.postmaster_result = ccache_reject;
1094 } /* Random not accepted */
1095 } /* MAIL FROM: accepted */
1097 /* For any failure of the main check, other than a negative response, we just
1098 close the connection and carry on. We can identify a negative response by the
1099 fact that errno is zero. For I/O errors it will be non-zero
1101 Set up different error texts for logging and for sending back to the caller
1102 as an SMTP response. Log in all cases, using a one-line format. For sender
1103 callouts, give a full response to the caller, but for recipient callouts,
1104 don't give the IP address because this may be an internal host whose identity
1105 is not to be widely broadcast. */
1109 if (errno == ETIMEDOUT)
1111 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
1114 else if (errno == 0)
1116 if (*responsebuffer == 0) Ustrcpy(responsebuffer, US"connection dropped");
1119 string_sprintf("response to \"%s\" from %s [%s] was: %s",
1120 big_buffer, host->name, host->address,
1121 string_printing(responsebuffer));
1123 addr->user_message = is_recipient?
1124 string_sprintf("Callout verification failed:\n%s", responsebuffer)
1126 string_sprintf("Called: %s\nSent: %s\nResponse: %s",
1127 host->address, big_buffer, responsebuffer);
1129 /* Hard rejection ends the process */
1131 if (responsebuffer[0] == '5') /* Address rejected */
1139 /* End the SMTP conversation and close the connection. */
1141 /* Cutthrough - on a successfull connect and recipient-verify with
1142 use-sender and we are 1st rcpt and have no cutthrough conn so far
1143 here is where we want to leave the conn open */
1144 if ( cutthrough.delivery
1148 && (options & (vopt_callout_recipsender|vopt_callout_recippmaster)) == vopt_callout_recipsender
1149 && !random_local_part
1151 && cutthrough.fd < 0
1154 cutthrough.fd = outblock.sock; /* We assume no buffer in use in the outblock */
1155 cutthrough.nrcpt = 1;
1156 cutthrough.interface = interface;
1157 cutthrough.host = *host;
1158 cutthrough.addr = *addr; /* Save the address_item for later logging */
1159 cutthrough.addr.next = NULL;
1160 cutthrough.addr.host_used = &cutthrough.host;
1162 *(cutthrough.addr.parent = store_get(sizeof(address_item))) =
1164 ctblock.buffer = ctbuffer;
1165 ctblock.buffersize = sizeof(ctbuffer);
1166 ctblock.ptr = ctbuffer;
1167 /* ctblock.cmd_count = 0; ctblock.authenticating = FALSE; */
1168 ctblock.sock = cutthrough.fd;
1172 /* Ensure no cutthrough on multiple address verifies */
1173 if (options & vopt_callout_recipsender)
1174 cancel_cutthrough_connection("multiple verify calls");
1175 if (send_quit) (void)smtp_write_command(&outblock, FALSE, "QUIT\r\n");
1178 tls_close(FALSE, TRUE);
1180 (void)close(inblock.sock);
1181 #ifdef EXPERIMENTAL_EVENT
1182 (void) event_raise(addr->transport->event_action,
1183 US"tcp:close", NULL);
1187 } /* Loop through all hosts, while !done */
1190 /* If we get here with done == TRUE, a successful callout happened, and yield
1191 will be set OK or FAIL according to the response to the RCPT command.
1192 Otherwise, we looped through the hosts but couldn't complete the business.
1193 However, there may be domain-specific information to cache in both cases.
1195 The value of the result field in the new_domain record is ccache_unknown if
1196 there was an error before or with MAIL FROM:, and errno was not zero,
1197 implying some kind of I/O error. We don't want to write the cache in that case.
1198 Otherwise the value is ccache_accept, ccache_reject, or ccache_reject_mfnull. */
1200 if (!callout_no_cache && new_domain_record.result != ccache_unknown)
1202 if ((dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE))
1205 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
1209 (void)dbfn_write(dbm_file, addr->domain, &new_domain_record,
1210 (int)sizeof(dbdata_callout_cache));
1211 HDEBUG(D_verify) debug_printf("wrote callout cache domain record:\n"
1212 " result=%d postmaster=%d random=%d\n",
1213 new_domain_record.result,
1214 new_domain_record.postmaster_result,
1215 new_domain_record.random_result);
1219 /* If a definite result was obtained for the callout, cache it unless caching
1224 if (!callout_no_cache && new_address_record.result != ccache_unknown)
1226 if (dbm_file == NULL)
1227 dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE);
1228 if (dbm_file == NULL)
1230 HDEBUG(D_verify) debug_printf("no callout cache available\n");
1234 (void)dbfn_write(dbm_file, address_key, &new_address_record,
1235 (int)sizeof(dbdata_callout_cache_address));
1236 HDEBUG(D_verify) debug_printf("wrote %s callout cache address record\n",
1237 (new_address_record.result == ccache_accept)? "positive" : "negative");
1242 /* Failure to connect to any host, or any response other than 2xx or 5xx is a
1243 temporary error. If there was only one host, and a response was received, leave
1244 it alone if supplying details. Otherwise, give a generic response. */
1248 uschar *dullmsg = string_sprintf("Could not complete %s verify callout",
1249 is_recipient? "recipient" : "sender");
1252 if (host_list->next != NULL || addr->message == NULL) addr->message = dullmsg;
1254 addr->user_message = (!smtp_return_error_details)? dullmsg :
1255 string_sprintf("%s for <%s>.\n"
1256 "The mail server(s) for the domain may be temporarily unreachable, or\n"
1257 "they may be permanently unreachable from this server. In the latter case,\n%s",
1258 dullmsg, addr->address,
1260 "the address will never be accepted."
1262 "you need to change the address or create an MX record for its domain\n"
1263 "if it is supposed to be generally accessible from the Internet.\n"
1264 "Talk to your mail administrator for details.");
1266 /* Force a specific error code */
1268 addr->basic_errno = ERRNO_CALLOUTDEFER;
1271 /* Come here from within the cache-reading code on fast-track exit. */
1274 if (dbm_file != NULL) dbfn_close(dbm_file);
1280 /* Called after recipient-acl to get a cutthrough connection open when
1281 one was requested and a recipient-verify wasn't subsequently done.
1284 open_cutthrough_connection( address_item * addr )
1288 /* Use a recipient-verify-callout to set up the cutthrough connection. */
1289 /* We must use a copy of the address for verification, because it might
1293 HDEBUG(D_acl) debug_printf("----------- %s cutthrough setup ------------\n",
1294 rcpt_count > 1 ? "more" : "start");
1295 (void) verify_address(&addr2, NULL,
1296 vopt_is_recipient | vopt_callout_recipsender | vopt_callout_no_cache,
1297 CUTTHROUGH_CMD_TIMEOUT, -1, -1,
1299 HDEBUG(D_acl) debug_printf("----------- end cutthrough setup ------------\n");
1305 /* Send given number of bytes from the buffer */
1307 cutthrough_send(int n)
1309 if(cutthrough.fd < 0)
1314 (tls_out.active == cutthrough.fd) ? tls_write(FALSE, ctblock.buffer, n) :
1316 send(cutthrough.fd, ctblock.buffer, n, 0) > 0
1319 transport_count += n;
1320 ctblock.ptr= ctblock.buffer;
1324 HDEBUG(D_transport|D_acl) debug_printf("cutthrough_send failed: %s\n", strerror(errno));
1331 _cutthrough_puts(uschar * cp, int n)
1335 if(ctblock.ptr >= ctblock.buffer+ctblock.buffersize)
1336 if(!cutthrough_send(ctblock.buffersize))
1339 *ctblock.ptr++ = *cp++;
1344 /* Buffered output of counted data block. Return boolean success */
1346 cutthrough_puts(uschar * cp, int n)
1348 if (cutthrough.fd < 0) return TRUE;
1349 if (_cutthrough_puts(cp, n)) return TRUE;
1350 cancel_cutthrough_connection("transmit failed");
1356 _cutthrough_flush_send(void)
1358 int n= ctblock.ptr-ctblock.buffer;
1361 if(!cutthrough_send(n))
1367 /* Send out any bufferred output. Return boolean success. */
1369 cutthrough_flush_send(void)
1371 if (_cutthrough_flush_send()) return TRUE;
1372 cancel_cutthrough_connection("transmit failed");
1378 cutthrough_put_nl(void)
1380 return cutthrough_puts(US"\r\n", 2);
1384 /* Get and check response from cutthrough target */
1386 cutthrough_response(char expect, uschar ** copy)
1388 smtp_inblock inblock;
1389 uschar inbuffer[4096];
1390 uschar responsebuffer[4096];
1392 inblock.buffer = inbuffer;
1393 inblock.buffersize = sizeof(inbuffer);
1394 inblock.ptr = inbuffer;
1395 inblock.ptrend = inbuffer;
1396 inblock.sock = cutthrough.fd;
1397 /* this relies on (inblock.sock == tls_out.active) */
1398 if(!smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), expect, CUTTHROUGH_DATA_TIMEOUT))
1399 cancel_cutthrough_connection("target timeout on read");
1404 *copy = cp = string_copy(responsebuffer);
1405 /* Trim the trailing end of line */
1406 cp += Ustrlen(responsebuffer);
1407 if(cp > *copy && cp[-1] == '\n') *--cp = '\0';
1408 if(cp > *copy && cp[-1] == '\r') *--cp = '\0';
1411 return responsebuffer[0];
1415 /* Negotiate dataphase with the cutthrough target, returning success boolean */
1417 cutthrough_predata(void)
1419 if(cutthrough.fd < 0)
1422 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> DATA\n");
1423 cutthrough_puts(US"DATA\r\n", 6);
1424 cutthrough_flush_send();
1426 /* Assume nothing buffered. If it was it gets ignored. */
1427 return cutthrough_response('3', NULL) == '3';
1431 /* fd and use_crlf args only to match write_chunk() */
1433 cutthrough_write_chunk(int fd, uschar * s, int len, BOOL use_crlf)
1436 while(s && (s2 = Ustrchr(s, '\n')))
1438 if(!cutthrough_puts(s, s2-s) || !cutthrough_put_nl())
1446 /* Buffered send of headers. Return success boolean. */
1447 /* Expands newlines to wire format (CR,NL). */
1448 /* Also sends header-terminating blank line. */
1450 cutthrough_headers_send(void)
1452 if(cutthrough.fd < 0)
1455 /* We share a routine with the mainline transport to handle header add/remove/rewrites,
1456 but having a separate buffered-output function (for now)
1458 HDEBUG(D_acl) debug_printf("----------- start cutthrough headers send -----------\n");
1460 if (!transport_headers_send(&cutthrough.addr, cutthrough.fd,
1461 cutthrough.addr.transport->add_headers,
1462 cutthrough.addr.transport->remove_headers,
1463 &cutthrough_write_chunk, TRUE,
1464 cutthrough.addr.transport->rewrite_rules,
1465 cutthrough.addr.transport->rewrite_existflags))
1468 HDEBUG(D_acl) debug_printf("----------- done cutthrough headers send ------------\n");
1474 close_cutthrough_connection(const char * why)
1476 if(cutthrough.fd >= 0)
1478 /* We could be sending this after a bunch of data, but that is ok as
1479 the only way to cancel the transfer in dataphase is to drop the tcp
1480 conn before the final dot.
1482 ctblock.ptr = ctbuffer;
1483 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> QUIT\n");
1484 _cutthrough_puts(US"QUIT\r\n", 6); /* avoid recursion */
1485 _cutthrough_flush_send();
1486 /* No wait for response */
1489 tls_close(FALSE, TRUE);
1491 (void)close(cutthrough.fd);
1493 HDEBUG(D_acl) debug_printf("----------- cutthrough shutdown (%s) ------------\n", why);
1495 ctblock.ptr = ctbuffer;
1499 cancel_cutthrough_connection(const char * why)
1501 close_cutthrough_connection(why);
1502 cutthrough.delivery = FALSE;
1508 /* Have senders final-dot. Send one to cutthrough target, and grab the response.
1509 Log an OK response as a transmission.
1510 Close the connection.
1511 Return smtp response-class digit.
1514 cutthrough_finaldot(void)
1517 address_item * addr;
1518 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> .\n");
1520 /* Assume data finshed with new-line */
1521 if( !cutthrough_puts(US".", 1)
1522 || !cutthrough_put_nl()
1523 || !cutthrough_flush_send()
1525 return cutthrough.addr.message;
1527 res = cutthrough_response('2', &cutthrough.addr.message);
1528 for (addr = &cutthrough.addr; addr; addr = addr->next)
1530 addr->message = cutthrough.addr.message;
1534 delivery_log(LOG_MAIN, addr, (int)'>', NULL);
1535 close_cutthrough_connection("delivered");
1539 delivery_log(LOG_MAIN, addr, 0,
1540 US"tmp-reject from cutthrough after DATA:");
1544 delivery_log(LOG_MAIN|LOG_REJECT, addr, 0,
1545 US"rejected after DATA:");
1552 return cutthrough.addr.message;
1557 /*************************************************
1558 * Copy error to toplevel address *
1559 *************************************************/
1561 /* This function is used when a verify fails or defers, to ensure that the
1562 failure or defer information is in the original toplevel address. This applies
1563 when an address is redirected to a single new address, and the failure or
1564 deferral happens to the child address.
1567 vaddr the verify address item
1568 addr the final address item
1571 Returns: the value of YIELD
1575 copy_error(address_item *vaddr, address_item *addr, int yield)
1579 vaddr->message = addr->message;
1580 vaddr->user_message = addr->user_message;
1581 vaddr->basic_errno = addr->basic_errno;
1582 vaddr->more_errno = addr->more_errno;
1583 vaddr->p.address_data = addr->p.address_data;
1584 copyflag(vaddr, addr, af_pass_message);
1592 /**************************************************
1593 * printf that automatically handles TLS if needed *
1594 ***************************************************/
1596 /* This function is used by verify_address() as a substitute for all fprintf()
1597 calls; a direct fprintf() will not produce output in a TLS SMTP session, such
1598 as a response to an EXPN command. smtp_in.c makes smtp_printf available but
1599 that assumes that we always use the smtp_out FILE* when not using TLS or the
1600 ssl buffer when we are. Instead we take a FILE* parameter and check to see if
1601 that is smtp_out; if so, smtp_printf() with TLS support, otherwise regular
1605 f the candidate FILE* to write to
1606 format format string
1607 ... optional arguments
1613 static void PRINTF_FUNCTION(2,3)
1614 respond_printf(FILE *f, const char *format, ...)
1618 va_start(ap, format);
1619 if (smtp_out && (f == smtp_out))
1620 smtp_vprintf(format, ap);
1622 vfprintf(f, format, ap);
1628 /*************************************************
1629 * Verify an email address *
1630 *************************************************/
1632 /* This function is used both for verification (-bv and at other times) and
1633 address testing (-bt), which is indicated by address_test_mode being set.
1636 vaddr contains the address to verify; the next field in this block
1638 f if not NULL, write the result to this file
1639 options various option bits:
1640 vopt_fake_sender => this sender verify is not for the real
1641 sender (it was verify=sender=xxxx or an address from a
1642 header line) - rewriting must not change sender_address
1643 vopt_is_recipient => this is a recipient address, otherwise
1644 it's a sender address - this affects qualification and
1645 rewriting and messages from callouts
1646 vopt_qualify => qualify an unqualified address; else error
1647 vopt_expn => called from SMTP EXPN command
1648 vopt_success_on_redirect => when a new address is generated
1649 the verification instantly succeeds
1651 These ones are used by do_callout() -- the options variable
1654 vopt_callout_fullpm => if postmaster check, do full one
1655 vopt_callout_no_cache => don't use callout cache
1656 vopt_callout_random => do the "random" thing
1657 vopt_callout_recipsender => use real sender for recipient
1658 vopt_callout_recippmaster => use postmaster for recipient
1660 callout if > 0, specifies that callout is required, and gives timeout
1661 for individual commands
1662 callout_overall if > 0, gives overall timeout for the callout function;
1663 if < 0, a default is used (see do_callout())
1664 callout_connect the connection timeout for callouts
1665 se_mailfrom when callout is requested to verify a sender, use this
1666 in MAIL FROM; NULL => ""
1667 pm_mailfrom when callout is requested, if non-NULL, do the postmaster
1668 thing and use this as the sender address (may be "")
1670 routed if not NULL, set TRUE if routing succeeded, so we can
1671 distinguish between routing failed and callout failed
1673 Returns: OK address verified
1674 FAIL address failed to verify
1675 DEFER can't tell at present
1679 verify_address(address_item *vaddr, FILE *f, int options, int callout,
1680 int callout_overall, int callout_connect, uschar *se_mailfrom,
1681 uschar *pm_mailfrom, BOOL *routed)
1684 BOOL full_info = (f == NULL)? FALSE : (debug_selector != 0);
1685 BOOL is_recipient = (options & vopt_is_recipient) != 0;
1686 BOOL expn = (options & vopt_expn) != 0;
1687 BOOL success_on_redirect = (options & vopt_success_on_redirect) != 0;
1690 int verify_type = expn? v_expn :
1691 address_test_mode? v_none :
1692 is_recipient? v_recipient : v_sender;
1693 address_item *addr_list;
1694 address_item *addr_new = NULL;
1695 address_item *addr_remote = NULL;
1696 address_item *addr_local = NULL;
1697 address_item *addr_succeed = NULL;
1698 uschar **failure_ptr = is_recipient?
1699 &recipient_verify_failure : &sender_verify_failure;
1700 uschar *ko_prefix, *cr;
1701 uschar *address = vaddr->address;
1702 uschar *save_sender;
1703 uschar null_sender[] = { 0 }; /* Ensure writeable memory */
1705 /* Clear, just in case */
1707 *failure_ptr = NULL;
1709 /* Set up a prefix and suffix for error message which allow us to use the same
1710 output statements both in EXPN mode (where an SMTP response is needed) and when
1711 debugging with an output file. */
1715 ko_prefix = US"553 ";
1718 else ko_prefix = cr = US"";
1720 /* Add qualify domain if permitted; otherwise an unqualified address fails. */
1722 if (parse_find_at(address) == NULL)
1724 if ((options & vopt_qualify) == 0)
1727 respond_printf(f, "%sA domain is required for \"%s\"%s\n",
1728 ko_prefix, address, cr);
1729 *failure_ptr = US"qualify";
1732 address = rewrite_address_qualify(address, is_recipient);
1737 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1738 debug_printf("%s %s\n", address_test_mode? "Testing" : "Verifying", address);
1741 /* Rewrite and report on it. Clear the domain and local part caches - these
1742 may have been set by domains and local part tests during an ACL. */
1744 if (global_rewrite_rules != NULL)
1746 uschar *old = address;
1747 address = rewrite_address(address, is_recipient, FALSE,
1748 global_rewrite_rules, rewrite_existflags);
1751 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->localpart_cache[i] = 0;
1752 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->domain_cache[i] = 0;
1753 if (f != NULL && !expn) fprintf(f, "Address rewritten as: %s\n", address);
1757 /* If this is the real sender address, we must update sender_address at
1758 this point, because it may be referred to in the routers. */
1760 if ((options & (vopt_fake_sender|vopt_is_recipient)) == 0)
1761 sender_address = address;
1763 /* If the address was rewritten to <> no verification can be done, and we have
1764 to return OK. This rewriting is permitted only for sender addresses; for other
1765 addresses, such rewriting fails. */
1767 if (address[0] == 0) return OK;
1769 /* Flip the legacy TLS-related variables over to the outbound set in case
1770 they're used in the context of a transport used by verification. Reset them
1771 at exit from this routine. */
1773 tls_modify_variables(&tls_out);
1775 /* Save a copy of the sender address for re-instating if we change it to <>
1776 while verifying a sender address (a nice bit of self-reference there). */
1778 save_sender = sender_address;
1780 /* Update the address structure with the possibly qualified and rewritten
1781 address. Set it up as the starting address on the chain of new addresses. */
1783 vaddr->address = address;
1786 /* We need a loop, because an address can generate new addresses. We must also
1787 cope with generated pipes and files at the top level. (See also the code and
1788 comment in deliver.c.) However, it is usually the case that the router for
1789 user's .forward files has its verify flag turned off.
1791 If an address generates more than one child, the loop is used only when
1792 full_info is set, and this can only be set locally. Remote enquiries just get
1793 information about the top level address, not anything that it generated. */
1795 while (addr_new != NULL)
1798 address_item *addr = addr_new;
1800 addr_new = addr->next;
1805 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1806 debug_printf("Considering %s\n", addr->address);
1809 /* Handle generated pipe, file or reply addresses. We don't get these
1810 when handling EXPN, as it does only one level of expansion. */
1812 if (testflag(addr, af_pfr))
1819 if (addr->address[0] == '>')
1821 allow = testflag(addr, af_allow_reply);
1822 fprintf(f, "%s -> mail %s", addr->parent->address, addr->address + 1);
1826 allow = (addr->address[0] == '|')?
1827 testflag(addr, af_allow_pipe) : testflag(addr, af_allow_file);
1828 fprintf(f, "%s -> %s", addr->parent->address, addr->address);
1831 if (addr->basic_errno == ERRNO_BADTRANSPORT)
1832 fprintf(f, "\n*** Error in setting up pipe, file, or autoreply:\n"
1833 "%s\n", addr->message);
1835 fprintf(f, "\n transport = %s\n", addr->transport->name);
1837 fprintf(f, " *** forbidden ***\n");
1842 /* Just in case some router parameter refers to it. */
1844 return_path = (addr->p.errors_address != NULL)?
1845 addr->p.errors_address : sender_address;
1847 /* Split the address into domain and local part, handling the %-hack if
1848 necessary, and then route it. While routing a sender address, set
1849 $sender_address to <> because that is what it will be if we were trying to
1850 send a bounce to the sender. */
1852 if (routed != NULL) *routed = FALSE;
1853 if ((rc = deliver_split_address(addr)) == OK)
1855 if (!is_recipient) sender_address = null_sender;
1856 rc = route_address(addr, &addr_local, &addr_remote, &addr_new,
1857 &addr_succeed, verify_type);
1858 sender_address = save_sender; /* Put back the real sender */
1861 /* If routing an address succeeded, set the flag that remembers, for use when
1862 an ACL cached a sender verify (in case a callout fails). Then if routing set
1863 up a list of hosts or the transport has a host list, and the callout option
1864 is set, and we aren't in a host checking run, do the callout verification,
1865 and set another flag that notes that a callout happened. */
1869 if (routed != NULL) *routed = TRUE;
1872 host_item *host_list = addr->host_list;
1874 /* Make up some data for use in the case where there is no remote
1877 transport_feedback tf = {
1878 NULL, /* interface (=> any) */
1879 US"smtp", /* port */
1880 US"smtp", /* protocol */
1882 US"$smtp_active_hostname", /* helo_data */
1883 FALSE, /* hosts_override */
1884 FALSE, /* hosts_randomize */
1885 FALSE, /* gethostbyname */
1886 TRUE, /* qualify_single */
1887 FALSE /* search_parents */
1890 /* If verification yielded a remote transport, we want to use that
1891 transport's options, so as to mimic what would happen if we were really
1892 sending a message to this address. */
1894 if (addr->transport != NULL && !addr->transport->info->local)
1896 (void)(addr->transport->setup)(addr->transport, addr, &tf, 0, 0, NULL);
1898 /* If the transport has hosts and the router does not, or if the
1899 transport is configured to override the router's hosts, we must build a
1900 host list of the transport's hosts, and find the IP addresses */
1902 if (tf.hosts != NULL && (host_list == NULL || tf.hosts_override))
1905 uschar *save_deliver_domain = deliver_domain;
1906 uschar *save_deliver_localpart = deliver_localpart;
1908 host_list = NULL; /* Ignore the router's hosts */
1910 deliver_domain = addr->domain;
1911 deliver_localpart = addr->local_part;
1912 s = expand_string(tf.hosts);
1913 deliver_domain = save_deliver_domain;
1914 deliver_localpart = save_deliver_localpart;
1918 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand list of hosts "
1919 "\"%s\" in %s transport for callout: %s", tf.hosts,
1920 addr->transport->name, expand_string_message);
1925 uschar *canonical_name;
1926 host_item *host, *nexthost;
1927 host_build_hostlist(&host_list, s, tf.hosts_randomize);
1929 /* Just ignore failures to find a host address. If we don't manage
1930 to find any addresses, the callout will defer. Note that more than
1931 one address may be found for a single host, which will result in
1932 additional host items being inserted into the chain. Hence we must
1933 save the next host first. */
1935 flags = HOST_FIND_BY_A;
1936 if (tf.qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
1937 if (tf.search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
1939 for (host = host_list; host != NULL; host = nexthost)
1941 nexthost = host->next;
1942 if (tf.gethostbyname ||
1943 string_is_ip_address(host->name, NULL) != 0)
1944 (void)host_find_byname(host, NULL, flags, &canonical_name, TRUE);
1947 uschar * d_request = NULL, * d_require = NULL;
1948 if (Ustrcmp(addr->transport->driver_name, "smtp") == 0)
1950 smtp_transport_options_block * ob =
1951 (smtp_transport_options_block *)
1952 addr->transport->options_block;
1953 d_request = ob->dnssec_request_domains;
1954 d_require = ob->dnssec_require_domains;
1957 (void)host_find_bydns(host, NULL, flags, NULL, NULL, NULL,
1958 d_request, d_require, &canonical_name, NULL);
1965 /* Can only do a callout if we have at least one host! If the callout
1966 fails, it will have set ${sender,recipient}_verify_failure. */
1968 if (host_list != NULL)
1970 HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n");
1971 if (host_checking && !host_checking_callout)
1974 debug_printf("... callout omitted by default when host testing\n"
1975 "(Use -bhc if you want the callouts to happen.)\n");
1980 deliver_set_expansions(addr);
1982 verify_mode = is_recipient ? US"R" : US"S";
1983 rc = do_callout(addr, host_list, &tf, callout, callout_overall,
1984 callout_connect, options, se_mailfrom, pm_mailfrom);
1990 HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor "
1991 "transport provided a host list\n");
1996 /* Otherwise, any failure is a routing failure */
1998 else *failure_ptr = US"route";
2000 /* A router may return REROUTED if it has set up a child address as a result
2001 of a change of domain name (typically from widening). In this case we always
2002 want to continue to verify the new child. */
2004 if (rc == REROUTED) continue;
2006 /* Handle hard failures */
2013 address_item *p = addr->parent;
2015 respond_printf(f, "%s%s %s", ko_prefix,
2016 full_info? addr->address : address,
2017 address_test_mode? "is undeliverable" : "failed to verify");
2018 if (!expn && admin_user)
2020 if (addr->basic_errno > 0)
2021 respond_printf(f, ": %s", strerror(addr->basic_errno));
2022 if (addr->message != NULL)
2023 respond_printf(f, ": %s", addr->message);
2026 /* Show parents iff doing full info */
2028 if (full_info) while (p != NULL)
2030 respond_printf(f, "%s\n <-- %s", cr, p->address);
2033 respond_printf(f, "%s\n", cr);
2035 cancel_cutthrough_connection("routing hard fail");
2039 yield = copy_error(vaddr, addr, FAIL);
2047 else if (rc == DEFER)
2052 address_item *p = addr->parent;
2053 respond_printf(f, "%s%s cannot be resolved at this time", ko_prefix,
2054 full_info? addr->address : address);
2055 if (!expn && admin_user)
2057 if (addr->basic_errno > 0)
2058 respond_printf(f, ": %s", strerror(addr->basic_errno));
2059 if (addr->message != NULL)
2060 respond_printf(f, ": %s", addr->message);
2061 else if (addr->basic_errno <= 0)
2062 respond_printf(f, ": unknown error");
2065 /* Show parents iff doing full info */
2067 if (full_info) while (p != NULL)
2069 respond_printf(f, "%s\n <-- %s", cr, p->address);
2072 respond_printf(f, "%s\n", cr);
2074 cancel_cutthrough_connection("routing soft fail");
2078 yield = copy_error(vaddr, addr, DEFER);
2081 else if (yield == OK) yield = DEFER;
2084 /* If we are handling EXPN, we do not want to continue to route beyond
2085 the top level (whose address is in "address"). */
2089 uschar *ok_prefix = US"250-";
2090 if (addr_new == NULL)
2092 if (addr_local == NULL && addr_remote == NULL)
2093 respond_printf(f, "250 mail to <%s> is discarded\r\n", address);
2095 respond_printf(f, "250 <%s>\r\n", address);
2097 else while (addr_new != NULL)
2099 address_item *addr2 = addr_new;
2100 addr_new = addr2->next;
2101 if (addr_new == NULL) ok_prefix = US"250 ";
2102 respond_printf(f, "%s<%s>\r\n", ok_prefix, addr2->address);
2108 /* Successful routing other than EXPN. */
2112 /* Handle successful routing when short info wanted. Otherwise continue for
2113 other (generated) addresses. Short info is the operational case. Full info
2114 can be requested only when debug_selector != 0 and a file is supplied.
2116 There is a conflict between the use of aliasing as an alternate email
2117 address, and as a sort of mailing list. If an alias turns the incoming
2118 address into just one address (e.g. J.Caesar->jc44) you may well want to
2119 carry on verifying the generated address to ensure it is valid when
2120 checking incoming mail. If aliasing generates multiple addresses, you
2121 probably don't want to do this. Exim therefore treats the generation of
2122 just a single new address as a special case, and continues on to verify the
2123 generated address. */
2125 if (!full_info && /* Stop if short info wanted AND */
2126 (((addr_new == NULL || /* No new address OR */
2127 addr_new->next != NULL || /* More than one new address OR */
2128 testflag(addr_new, af_pfr))) /* New address is pfr */
2130 (addr_new != NULL && /* At least one new address AND */
2131 success_on_redirect))) /* success_on_redirect is set */
2133 if (f != NULL) fprintf(f, "%s %s\n", address,
2134 address_test_mode? "is deliverable" : "verified");
2136 /* If we have carried on to verify a child address, we want the value
2137 of $address_data to be that of the child */
2139 vaddr->p.address_data = addr->p.address_data;
2144 } /* Loop for generated addresses */
2146 /* Display the full results of the successful routing, including any generated
2147 addresses. Control gets here only when full_info is set, which requires f not
2148 to be NULL, and this occurs only when a top-level verify is called with the
2149 debugging switch on.
2151 If there are no local and no remote addresses, and there were no pipes, files,
2152 or autoreplies, and there were no errors or deferments, the message is to be
2153 discarded, usually because of the use of :blackhole: in an alias file. */
2155 if (allok && addr_local == NULL && addr_remote == NULL)
2157 fprintf(f, "mail to %s is discarded\n", address);
2161 for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++)
2163 while (addr_list != NULL)
2165 address_item *addr = addr_list;
2166 address_item *p = addr->parent;
2167 addr_list = addr->next;
2169 fprintf(f, "%s", CS addr->address);
2170 #ifdef EXPERIMENTAL_SRS
2171 if(addr->p.srs_sender)
2172 fprintf(f, " [srs = %s]", addr->p.srs_sender);
2175 /* If the address is a duplicate, show something about it. */
2177 if (!testflag(addr, af_pfr))
2180 if ((tnode = tree_search(tree_duplicates, addr->unique)) != NULL)
2181 fprintf(f, " [duplicate, would not be delivered]");
2182 else tree_add_duplicate(addr->unique, addr);
2185 /* Now show its parents */
2189 fprintf(f, "\n <-- %s", p->address);
2194 /* Show router, and transport */
2196 fprintf(f, "router = %s, ", addr->router->name);
2197 fprintf(f, "transport = %s\n", (addr->transport == NULL)? US"unset" :
2198 addr->transport->name);
2200 /* Show any hosts that are set up by a router unless the transport
2201 is going to override them; fiddle a bit to get a nice format. */
2203 if (addr->host_list != NULL && addr->transport != NULL &&
2204 !addr->transport->overrides_hosts)
2209 for (h = addr->host_list; h != NULL; h = h->next)
2211 int len = Ustrlen(h->name);
2212 if (len > maxlen) maxlen = len;
2213 len = (h->address != NULL)? Ustrlen(h->address) : 7;
2214 if (len > maxaddlen) maxaddlen = len;
2216 for (h = addr->host_list; h != NULL; h = h->next)
2218 int len = Ustrlen(h->name);
2219 fprintf(f, " host %s ", h->name);
2220 while (len++ < maxlen) fprintf(f, " ");
2221 if (h->address != NULL)
2223 fprintf(f, "[%s] ", h->address);
2224 len = Ustrlen(h->address);
2226 else if (!addr->transport->info->local) /* Omit [unknown] for local */
2228 fprintf(f, "[unknown] ");
2232 while (len++ < maxaddlen) fprintf(f," ");
2233 if (h->mx >= 0) fprintf(f, "MX=%d", h->mx);
2234 if (h->port != PORT_NONE) fprintf(f, " port=%d", h->port);
2235 if (h->status == hstatus_unusable) fprintf(f, " ** unusable **");
2242 /* Yield will be DEFER or FAIL if any one address has, only for full_info (which is
2243 the -bv or -bt case). */
2246 tls_modify_variables(&tls_in);
2254 /*************************************************
2255 * Check headers for syntax errors *
2256 *************************************************/
2258 /* This function checks those header lines that contain addresses, and verifies
2259 that all the addresses therein are syntactially correct.
2262 msgptr where to put an error message
2269 verify_check_headers(uschar **msgptr)
2275 for (h = header_list; h != NULL && yield == OK; h = h->next)
2277 if (h->type != htype_from &&
2278 h->type != htype_reply_to &&
2279 h->type != htype_sender &&
2280 h->type != htype_to &&
2281 h->type != htype_cc &&
2282 h->type != htype_bcc)
2285 colon = Ustrchr(h->text, ':');
2287 while (isspace(*s)) s++;
2289 /* Loop for multiple addresses in the header, enabling group syntax. Note
2290 that we have to reset this after the header has been scanned. */
2292 parse_allow_group = TRUE;
2296 uschar *ss = parse_find_address_end(s, FALSE);
2297 uschar *recipient, *errmess;
2298 int terminator = *ss;
2299 int start, end, domain;
2301 /* Temporarily terminate the string at this point, and extract the
2302 operative address within, allowing group syntax. */
2305 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2308 /* Permit an unqualified address only if the message is local, or if the
2309 sending host is configured to be permitted to send them. */
2311 if (recipient != NULL && domain == 0)
2313 if (h->type == htype_from || h->type == htype_sender)
2315 if (!allow_unqualified_sender) recipient = NULL;
2319 if (!allow_unqualified_recipient) recipient = NULL;
2321 if (recipient == NULL) errmess = US"unqualified address not permitted";
2324 /* It's an error if no address could be extracted, except for the special
2325 case of an empty address. */
2327 if (recipient == NULL && Ustrcmp(errmess, "empty address") != 0)
2329 uschar *verb = US"is";
2334 /* Arrange not to include any white space at the end in the
2335 error message or the header name. */
2337 while (t > s && isspace(t[-1])) t--;
2338 while (tt > h->text && isspace(tt[-1])) tt--;
2340 /* Add the address that failed to the error message, since in a
2341 header with very many addresses it is sometimes hard to spot
2342 which one is at fault. However, limit the amount of address to
2343 quote - cases have been seen where, for example, a missing double
2344 quote in a humungous To: header creates an "address" that is longer
2345 than string_sprintf can handle. */
2354 *msgptr = string_printing(
2355 string_sprintf("%s: failing address in \"%.*s:\" header %s: %.*s",
2356 errmess, tt - h->text, h->text, verb, len, s));
2359 break; /* Out of address loop */
2362 /* Advance to the next address */
2364 s = ss + (terminator? 1:0);
2365 while (isspace(*s)) s++;
2366 } /* Next address */
2368 parse_allow_group = FALSE;
2369 parse_found_group = FALSE;
2370 } /* Next header unless yield has been set FALSE */
2376 /*************************************************
2377 * Check header names for 8-bit characters *
2378 *************************************************/
2380 /* This function checks for invalid charcters in header names. See
2381 RFC 5322, 2.2. and RFC 6532, 3.
2384 msgptr where to put an error message
2391 verify_check_header_names_ascii(uschar **msgptr)
2396 for (h = header_list; h != NULL; h = h->next)
2398 colon = Ustrchr(h->text, ':');
2399 for(s = h->text; s < colon; s++)
2401 if ((*s < 33) || (*s > 126))
2403 *msgptr = string_sprintf("Invalid character in header \"%.*s\" found",
2404 colon - h->text, h->text);
2412 /*************************************************
2413 * Check for blind recipients *
2414 *************************************************/
2416 /* This function checks that every (envelope) recipient is mentioned in either
2417 the To: or Cc: header lines, thus detecting blind carbon copies.
2419 There are two ways of scanning that could be used: either scan the header lines
2420 and tick off the recipients, or scan the recipients and check the header lines.
2421 The original proposed patch did the former, but I have chosen to do the latter,
2422 because (a) it requires no memory and (b) will use fewer resources when there
2423 are many addresses in To: and/or Cc: and only one or two envelope recipients.
2426 Returns: OK if there are no blind recipients
2427 FAIL if there is at least one blind recipient
2431 verify_check_notblind(void)
2434 for (i = 0; i < recipients_count; i++)
2438 uschar *address = recipients_list[i].address;
2440 for (h = header_list; !found && h != NULL; h = h->next)
2444 if (h->type != htype_to && h->type != htype_cc) continue;
2446 colon = Ustrchr(h->text, ':');
2448 while (isspace(*s)) s++;
2450 /* Loop for multiple addresses in the header, enabling group syntax. Note
2451 that we have to reset this after the header has been scanned. */
2453 parse_allow_group = TRUE;
2457 uschar *ss = parse_find_address_end(s, FALSE);
2458 uschar *recipient,*errmess;
2459 int terminator = *ss;
2460 int start, end, domain;
2462 /* Temporarily terminate the string at this point, and extract the
2463 operative address within, allowing group syntax. */
2466 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2469 /* If we found a valid recipient that has a domain, compare it with the
2470 envelope recipient. Local parts are compared case-sensitively, domains
2471 case-insensitively. By comparing from the start with length "domain", we
2472 include the "@" at the end, which ensures that we are comparing the whole
2473 local part of each address. */
2475 if (recipient != NULL && domain != 0)
2477 found = Ustrncmp(recipient, address, domain) == 0 &&
2478 strcmpic(recipient + domain, address + domain) == 0;
2482 /* Advance to the next address */
2484 s = ss + (terminator? 1:0);
2485 while (isspace(*s)) s++;
2486 } /* Next address */
2488 parse_allow_group = FALSE;
2489 parse_found_group = FALSE;
2490 } /* Next header (if found is false) */
2492 if (!found) return FAIL;
2493 } /* Next recipient */
2500 /*************************************************
2501 * Find if verified sender *
2502 *************************************************/
2504 /* Usually, just a single address is verified as the sender of the message.
2505 However, Exim can be made to verify other addresses as well (often related in
2506 some way), and this is useful in some environments. There may therefore be a
2507 chain of such addresses that have previously been tested. This function finds
2508 whether a given address is on the chain.
2510 Arguments: the address to be verified
2511 Returns: pointer to an address item, or NULL
2515 verify_checked_sender(uschar *sender)
2518 for (addr = sender_verified_list; addr != NULL; addr = addr->next)
2519 if (Ustrcmp(sender, addr->address) == 0) break;
2527 /*************************************************
2528 * Get valid header address *
2529 *************************************************/
2531 /* Scan the originator headers of the message, looking for an address that
2532 verifies successfully. RFC 822 says:
2534 o The "Sender" field mailbox should be sent notices of
2535 any problems in transport or delivery of the original
2536 messages. If there is no "Sender" field, then the
2537 "From" field mailbox should be used.
2539 o If the "Reply-To" field exists, then the reply should
2540 go to the addresses indicated in that field and not to
2541 the address(es) indicated in the "From" field.
2543 So we check a Sender field if there is one, else a Reply_to field, else a From
2544 field. As some strange messages may have more than one of these fields,
2545 especially if they are resent- fields, check all of them if there is more than
2549 user_msgptr points to where to put a user error message
2550 log_msgptr points to where to put a log error message
2551 callout timeout for callout check (passed to verify_address())
2552 callout_overall overall callout timeout (ditto)
2553 callout_connect connect callout timeout (ditto)
2554 se_mailfrom mailfrom for verify; NULL => ""
2555 pm_mailfrom sender for pm callout check (passed to verify_address())
2556 options callout options (passed to verify_address())
2557 verrno where to put the address basic_errno
2559 If log_msgptr is set to something without setting user_msgptr, the caller
2560 normally uses log_msgptr for both things.
2562 Returns: result of the verification attempt: OK, FAIL, or DEFER;
2563 FAIL is given if no appropriate headers are found
2567 verify_check_header_address(uschar **user_msgptr, uschar **log_msgptr,
2568 int callout, int callout_overall, int callout_connect, uschar *se_mailfrom,
2569 uschar *pm_mailfrom, int options, int *verrno)
2571 static int header_types[] = { htype_sender, htype_reply_to, htype_from };
2576 for (i = 0; i < 3 && !done; i++)
2579 for (h = header_list; h != NULL && !done; h = h->next)
2581 int terminator, new_ok;
2582 uschar *s, *ss, *endname;
2584 if (h->type != header_types[i]) continue;
2585 s = endname = Ustrchr(h->text, ':') + 1;
2587 /* Scan the addresses in the header, enabling group syntax. Note that we
2588 have to reset this after the header has been scanned. */
2590 parse_allow_group = TRUE;
2594 address_item *vaddr;
2596 while (isspace(*s) || *s == ',') s++;
2597 if (*s == 0) break; /* End of header */
2599 ss = parse_find_address_end(s, FALSE);
2601 /* The terminator is a comma or end of header, but there may be white
2602 space preceding it (including newline for the last address). Move back
2603 past any white space so we can check against any cached envelope sender
2604 address verifications. */
2606 while (isspace(ss[-1])) ss--;
2610 HDEBUG(D_verify) debug_printf("verifying %.*s header address %s\n",
2611 (int)(endname - h->text), h->text, s);
2613 /* See if we have already verified this address as an envelope sender,
2614 and if so, use the previous answer. */
2616 vaddr = verify_checked_sender(s);
2618 if (vaddr != NULL && /* Previously checked */
2619 (callout <= 0 || /* No callout needed; OR */
2620 vaddr->special_action > 256)) /* Callout was done */
2622 new_ok = vaddr->special_action & 255;
2623 HDEBUG(D_verify) debug_printf("previously checked as envelope sender\n");
2624 *ss = terminator; /* Restore shortened string */
2627 /* Otherwise we run the verification now. We must restore the shortened
2628 string before running the verification, so the headers are correct, in
2629 case there is any rewriting. */
2633 int start, end, domain;
2634 uschar *address = parse_extract_address(s, log_msgptr, &start, &end,
2639 /* If we found an empty address, just carry on with the next one, but
2640 kill the message. */
2642 if (address == NULL && Ustrcmp(*log_msgptr, "empty address") == 0)
2649 /* If verification failed because of a syntax error, fail this
2650 function, and ensure that the failing address gets added to the error
2653 if (address == NULL)
2656 while (ss > s && isspace(ss[-1])) ss--;
2657 *log_msgptr = string_sprintf("syntax error in '%.*s' header when "
2658 "scanning for sender: %s in \"%.*s\"",
2659 endname - h->text, h->text, *log_msgptr, ss - s, s);
2665 /* Else go ahead with the sender verification. But it isn't *the*
2666 sender of the message, so set vopt_fake_sender to stop sender_address
2667 being replaced after rewriting or qualification. */
2671 vaddr = deliver_make_addr(address, FALSE);
2672 new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender,
2673 callout, callout_overall, callout_connect, se_mailfrom,
2678 /* We now have the result, either newly found, or cached. If we are
2679 giving out error details, set a specific user error. This means that the
2680 last of these will be returned to the user if all three fail. We do not
2681 set a log message - the generic one below will be used. */
2685 *verrno = vaddr->basic_errno;
2686 if (smtp_return_error_details)
2688 *user_msgptr = string_sprintf("Rejected after DATA: "
2689 "could not verify \"%.*s\" header address\n%s: %s",
2690 endname - h->text, h->text, vaddr->address, vaddr->message);
2694 /* Success or defer */
2703 if (new_ok == DEFER) yield = DEFER;
2705 /* Move on to any more addresses in the header */
2708 } /* Next address */
2710 parse_allow_group = FALSE;
2711 parse_found_group = FALSE;
2712 } /* Next header, unless done */
2713 } /* Next header type unless done */
2715 if (yield == FAIL && *log_msgptr == NULL)
2716 *log_msgptr = US"there is no valid sender in any header line";
2718 if (yield == DEFER && *log_msgptr == NULL)
2719 *log_msgptr = US"all attempts to verify a sender in a header line deferred";
2727 /*************************************************
2728 * Get RFC 1413 identification *
2729 *************************************************/
2731 /* Attempt to get an id from the sending machine via the RFC 1413 protocol. If
2732 the timeout is set to zero, then the query is not done. There may also be lists
2733 of hosts and nets which are exempt. To guard against malefactors sending
2734 non-printing characters which could, for example, disrupt a message's headers,
2735 make sure the string consists of printing characters only.
2738 port the port to connect to; usually this is IDENT_PORT (113), but when
2739 running in the test harness with -bh a different value is used.
2743 Side effect: any received ident value is put in sender_ident (NULL otherwise)
2747 verify_get_ident(int port)
2749 int sock, host_af, qlen;
2750 int received_sender_port, received_interface_port, n;
2752 uschar buffer[2048];
2754 /* Default is no ident. Check whether we want to do an ident check for this
2757 sender_ident = NULL;
2758 if (rfc1413_query_timeout <= 0 || verify_check_host(&rfc1413_hosts) != OK)
2761 DEBUG(D_ident) debug_printf("doing ident callback\n");
2763 /* Set up a connection to the ident port of the remote host. Bind the local end
2764 to the incoming interface address. If the sender host address is an IPv6
2765 address, the incoming interface address will also be IPv6. */
2767 host_af = (Ustrchr(sender_host_address, ':') == NULL)? AF_INET : AF_INET6;
2768 sock = ip_socket(SOCK_STREAM, host_af);
2769 if (sock < 0) return;
2771 if (ip_bind(sock, host_af, interface_address, 0) < 0)
2773 DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n",
2778 if (ip_connect(sock, host_af, sender_host_address, port, rfc1413_query_timeout)
2781 if (errno == ETIMEDOUT && (log_extra_selector & LX_ident_timeout) != 0)
2783 log_write(0, LOG_MAIN, "ident connection to %s timed out",
2784 sender_host_address);
2788 DEBUG(D_ident) debug_printf("ident connection to %s failed: %s\n",
2789 sender_host_address, strerror(errno));
2794 /* Construct and send the query. */
2796 sprintf(CS buffer, "%d , %d\r\n", sender_host_port, interface_port);
2797 qlen = Ustrlen(buffer);
2798 if (send(sock, buffer, qlen, 0) < 0)
2800 DEBUG(D_ident) debug_printf("ident send failed: %s\n", strerror(errno));
2804 /* Read a response line. We put it into the rest of the buffer, using several
2805 recv() calls if necessary. */
2813 int size = sizeof(buffer) - (p - buffer);
2815 if (size <= 0) goto END_OFF; /* Buffer filled without seeing \n. */
2816 count = ip_recv(sock, p, size, rfc1413_query_timeout);
2817 if (count <= 0) goto END_OFF; /* Read error or EOF */
2819 /* Scan what we just read, to see if we have reached the terminating \r\n. Be
2820 generous, and accept a plain \n terminator as well. The only illegal
2823 for (pp = p; pp < p + count; pp++)
2825 if (*pp == 0) goto END_OFF; /* Zero octet not allowed */
2828 if (pp[-1] == '\r') pp--;
2830 goto GOT_DATA; /* Break out of both loops */
2834 /* Reached the end of the data without finding \n. Let the loop continue to
2835 read some more, if there is room. */
2842 /* We have received a line of data. Check it carefully. It must start with the
2843 same two port numbers that we sent, followed by data as defined by the RFC. For
2846 12345 , 25 : USERID : UNIX :root
2848 However, the amount of white space may be different to what we sent. In the
2849 "osname" field there may be several sub-fields, comma separated. The data we
2850 actually want to save follows the third colon. Some systems put leading spaces
2851 in it - we discard those. */
2853 if (sscanf(CS buffer + qlen, "%d , %d%n", &received_sender_port,
2854 &received_interface_port, &n) != 2 ||
2855 received_sender_port != sender_host_port ||
2856 received_interface_port != interface_port)
2859 p = buffer + qlen + n;
2860 while(isspace(*p)) p++;
2861 if (*p++ != ':') goto END_OFF;
2862 while(isspace(*p)) p++;
2863 if (Ustrncmp(p, "USERID", 6) != 0) goto END_OFF;
2865 while(isspace(*p)) p++;
2866 if (*p++ != ':') goto END_OFF;
2867 while (*p != 0 && *p != ':') p++;
2868 if (*p++ == 0) goto END_OFF;
2869 while(isspace(*p)) p++;
2870 if (*p == 0) goto END_OFF;
2872 /* The rest of the line is the data we want. We turn it into printing
2873 characters when we save it, so that it cannot mess up the format of any logging
2874 or Received: lines into which it gets inserted. We keep a maximum of 127
2877 sender_ident = string_printing(string_copyn(p, 127));
2878 DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident);
2888 /*************************************************
2889 * Match host to a single host-list item *
2890 *************************************************/
2892 /* This function compares a host (name or address) against a single item
2893 from a host list. The host name gets looked up if it is needed and is not
2894 already known. The function is called from verify_check_this_host() via
2895 match_check_list(), which is why most of its arguments are in a single block.
2898 arg the argument block (see below)
2899 ss the host-list item
2900 valueptr where to pass back looked up data, or NULL
2901 error for error message when returning ERROR
2904 host_name (a) the host name, or
2905 (b) NULL, implying use sender_host_name and
2906 sender_host_aliases, looking them up if required, or
2907 (c) the empty string, meaning that only IP address matches
2909 host_address the host address
2910 host_ipv4 the IPv4 address taken from an IPv6 one
2914 DEFER lookup deferred
2915 ERROR (a) failed to find the host name or IP address, or
2916 (b) unknown lookup type specified, or
2917 (c) host name encountered when only IP addresses are
2922 check_host(void *arg, uschar *ss, uschar **valueptr, uschar **error)
2924 check_host_block *cb = (check_host_block *)arg;
2927 BOOL iplookup = FALSE;
2928 BOOL isquery = FALSE;
2929 BOOL isiponly = cb->host_name != NULL && cb->host_name[0] == 0;
2934 /* Optimize for the special case when the pattern is "*". */
2936 if (*ss == '*' && ss[1] == 0) return OK;
2938 /* If the pattern is empty, it matches only in the case when there is no host -
2939 this can occur in ACL checking for SMTP input using the -bs option. In this
2940 situation, the host address is the empty string. */
2942 if (cb->host_address[0] == 0) return (*ss == 0)? OK : FAIL;
2943 if (*ss == 0) return FAIL;
2945 /* If the pattern is precisely "@" then match against the primary host name,
2946 provided that host name matching is permitted; if it's "@[]" match against the
2947 local host's IP addresses. */
2953 if (isiponly) return ERROR;
2954 ss = primary_hostname;
2956 else if (Ustrcmp(ss, "@[]") == 0)
2958 ip_address_item *ip;
2959 for (ip = host_find_interfaces(); ip != NULL; ip = ip->next)
2960 if (Ustrcmp(ip->address, cb->host_address) == 0) return OK;
2965 /* If the pattern is an IP address, optionally followed by a bitmask count, do
2966 a (possibly masked) comparision with the current IP address. */
2968 if (string_is_ip_address(ss, &maskoffset) != 0)
2969 return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL);
2971 /* The pattern is not an IP address. A common error that people make is to omit
2972 one component of an IPv4 address, either by accident, or believing that, for
2973 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,
2974 which it isn't. (Those applications that do accept 1.2.3 as an IP address
2975 interpret it as 1.2.0.3 because the final component becomes 16-bit - this is an
2976 ancient specification.) To aid in debugging these cases, we give a specific
2977 error if the pattern contains only digits and dots or contains a slash preceded
2978 only by digits and dots (a slash at the start indicates a file name and of
2979 course slashes may be present in lookups, but not preceded only by digits and
2982 for (t = ss; isdigit(*t) || *t == '.'; t++);
2983 if (*t == 0 || (*t == '/' && t != ss))
2985 *error = US"malformed IPv4 address or address mask";
2989 /* See if there is a semicolon in the pattern */
2991 semicolon = Ustrchr(ss, ';');
2993 /* If we are doing an IP address only match, then all lookups must be IP
2994 address lookups, even if there is no "net-". */
2998 iplookup = semicolon != NULL;
3001 /* Otherwise, if the item is of the form net[n]-lookup;<file|query> then it is
3002 a lookup on a masked IP network, in textual form. We obey this code even if we
3003 have already set iplookup, so as to skip over the "net-" prefix and to set the
3004 mask length. The net- stuff really only applies to single-key lookups where the
3005 key is implicit. For query-style lookups the key is specified in the query.
3006 From release 4.30, the use of net- for query style is no longer needed, but we
3007 retain it for backward compatibility. */
3009 if (Ustrncmp(ss, "net", 3) == 0 && semicolon != NULL)
3012 for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0';
3013 if (mlen == 0 && t == ss+3) mlen = -1; /* No mask supplied */
3014 iplookup = (*t++ == '-');
3018 /* Do the IP address lookup if that is indeed what we have */
3026 uschar *filename, *key, *result;
3029 /* Find the search type */
3031 search_type = search_findtype(t, semicolon - t);
3033 if (search_type < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
3034 search_error_message);
3036 /* Adjust parameters for the type of lookup. For a query-style lookup, there
3037 is no file name, and the "key" is just the query. For query-style with a file
3038 name, we have to fish the file off the start of the query. For a single-key
3039 lookup, the key is the current IP address, masked appropriately, and
3040 reconverted to text form, with the mask appended. For IPv6 addresses, specify
3041 dot separators instead of colons, except when the lookup type is "iplsearch".
3044 if (mac_islookup(search_type, lookup_absfilequery))
3046 filename = semicolon + 1;
3048 while (*key != 0 && !isspace(*key)) key++;
3049 filename = string_copyn(filename, key - filename);
3050 while (isspace(*key)) key++;
3052 else if (mac_islookup(search_type, lookup_querystyle))
3055 key = semicolon + 1;
3057 else /* Single-key style */
3059 int sep = (Ustrcmp(lookup_list[search_type]->name, "iplsearch") == 0)?
3061 insize = host_aton(cb->host_address, incoming);
3062 host_mask(insize, incoming, mlen);
3063 (void)host_nmtoa(insize, incoming, mlen, buffer, sep);
3065 filename = semicolon + 1;
3068 /* Now do the actual lookup; note that there is no search_close() because
3069 of the caching arrangements. */
3071 handle = search_open(filename, search_type, 0, NULL, NULL);
3072 if (handle == NULL) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
3073 search_error_message);
3074 result = search_find(handle, filename, key, -1, NULL, 0, 0, NULL);
3075 if (valueptr != NULL) *valueptr = result;
3076 return (result != NULL)? OK : search_find_defer? DEFER: FAIL;
3079 /* The pattern is not an IP address or network reference of any kind. That is,
3080 it is a host name pattern. If this is an IP only match, there's an error in the
3085 *error = US"cannot match host name in match_ip list";
3089 /* Check the characters of the pattern to see if they comprise only letters,
3090 digits, full stops, and hyphens (the constituents of domain names). Allow
3091 underscores, as they are all too commonly found. Sigh. Also, if
3092 allow_utf8_domains is set, allow top-bit characters. */
3094 for (t = ss; *t != 0; t++)
3095 if (!isalnum(*t) && *t != '.' && *t != '-' && *t != '_' &&
3096 (!allow_utf8_domains || *t < 128)) break;
3098 /* If the pattern is a complete domain name, with no fancy characters, look up
3099 its IP address and match against that. Note that a multi-homed host will add
3100 items to the chain. */
3111 rc = host_find_byname(&h, NULL, HOST_FIND_QUALIFY_SINGLE, NULL, FALSE);
3112 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3115 for (hh = &h; hh != NULL; hh = hh->next)
3117 if (host_is_in_net(hh->address, cb->host_address, 0)) return OK;
3121 if (rc == HOST_FIND_AGAIN) return DEFER;
3122 *error = string_sprintf("failed to find IP address for %s", ss);
3126 /* Almost all subsequent comparisons require the host name, and can be done
3127 using the general string matching function. When this function is called for
3128 outgoing hosts, the name is always given explicitly. If it is NULL, it means we
3129 must use sender_host_name and its aliases, looking them up if necessary. */
3131 if (cb->host_name != NULL) /* Explicit host name given */
3132 return match_check_string(cb->host_name, ss, -1, TRUE, TRUE, TRUE,
3135 /* Host name not given; in principle we need the sender host name and its
3136 aliases. However, for query-style lookups, we do not need the name if the
3137 query does not contain $sender_host_name. From release 4.23, a reference to
3138 $sender_host_name causes it to be looked up, so we don't need to do the lookup
3141 if ((semicolon = Ustrchr(ss, ';')) != NULL)
3144 int partial, affixlen, starflags, id;
3147 id = search_findtype_partial(ss, &partial, &affix, &affixlen, &starflags);
3150 if (id < 0) /* Unknown lookup type */
3152 log_write(0, LOG_MAIN|LOG_PANIC, "%s in host list item \"%s\"",
3153 search_error_message, ss);
3156 isquery = mac_islookup(id, lookup_querystyle|lookup_absfilequery);
3161 switch(match_check_string(US"", ss, -1, TRUE, TRUE, TRUE, valueptr))
3164 case DEFER: return DEFER;
3165 default: return FAIL;
3169 /* Not a query-style lookup; must ensure the host name is present, and then we
3170 do a check on the name and all its aliases. */
3172 if (sender_host_name == NULL)
3174 HDEBUG(D_host_lookup)
3175 debug_printf("sender host name required, to match against %s\n", ss);
3176 if (host_lookup_failed || host_name_lookup() != OK)
3178 *error = string_sprintf("failed to find host name for %s",
3179 sender_host_address);;
3182 host_build_sender_fullhost();
3185 /* Match on the sender host name, using the general matching function */
3187 switch(match_check_string(sender_host_name, ss, -1, TRUE, TRUE, TRUE,
3191 case DEFER: return DEFER;
3194 /* If there are aliases, try matching on them. */
3196 aliases = sender_host_aliases;
3197 while (*aliases != NULL)
3199 switch(match_check_string(*aliases++, ss, -1, TRUE, TRUE, TRUE, valueptr))
3202 case DEFER: return DEFER;
3211 /*************************************************
3212 * Check a specific host matches a host list *
3213 *************************************************/
3215 /* This function is passed a host list containing items in a number of
3216 different formats and the identity of a host. Its job is to determine whether
3217 the given host is in the set of hosts defined by the list. The host name is
3218 passed as a pointer so that it can be looked up if needed and not already
3219 known. This is commonly the case when called from verify_check_host() to check
3220 an incoming connection. When called from elsewhere the host name should usually
3223 This function is now just a front end to match_check_list(), which runs common
3224 code for scanning a list. We pass it the check_host() function to perform a
3228 listptr pointer to the host list
3229 cache_bits pointer to cache for named lists, or NULL
3230 host_name the host name or NULL, implying use sender_host_name and
3231 sender_host_aliases, looking them up if required
3232 host_address the IP address
3233 valueptr if not NULL, data from a lookup is passed back here
3235 Returns: OK if the host is in the defined set
3236 FAIL if the host is not in the defined set,
3237 DEFER if a data lookup deferred (not a host lookup)
3239 If the host name was needed in order to make a comparison, and could not be
3240 determined from the IP address, the result is FAIL unless the item
3241 "+allow_unknown" was met earlier in the list, in which case OK is returned. */
3244 verify_check_this_host(uschar **listptr, unsigned int *cache_bits,
3245 uschar *host_name, uschar *host_address, uschar **valueptr)
3248 unsigned int *local_cache_bits = cache_bits;
3249 uschar *save_host_address = deliver_host_address;
3250 check_host_block cb;
3251 cb.host_name = host_name;
3252 cb.host_address = host_address;
3254 if (valueptr != NULL) *valueptr = NULL;
3256 /* If the host address starts off ::ffff: it is an IPv6 address in
3257 IPv4-compatible mode. Find the IPv4 part for checking against IPv4
3260 cb.host_ipv4 = (Ustrncmp(host_address, "::ffff:", 7) == 0)?
3261 host_address + 7 : host_address;
3263 /* During the running of the check, put the IP address into $host_address. In
3264 the case of calls from the smtp transport, it will already be there. However,
3265 in other calls (e.g. when testing ignore_target_hosts), it won't. Just to be on
3266 the safe side, any existing setting is preserved, though as I write this
3267 (November 2004) I can't see any cases where it is actually needed. */
3269 deliver_host_address = host_address;
3270 rc = match_check_list(
3271 listptr, /* the list */
3272 0, /* separator character */
3273 &hostlist_anchor, /* anchor pointer */
3274 &local_cache_bits, /* cache pointer */
3275 check_host, /* function for testing */
3276 &cb, /* argument for function */
3277 MCL_HOST, /* type of check */
3278 (host_address == sender_host_address)?
3279 US"host" : host_address, /* text for debugging */
3280 valueptr); /* where to pass back data */
3281 deliver_host_address = save_host_address;
3288 /*************************************************
3289 * Check the given host item matches a list *
3290 *************************************************/
3292 verify_check_given_host(uschar **listptr, host_item *host)
3294 return verify_check_this_host(listptr, NULL, host->name, host->address, NULL);
3297 /*************************************************
3298 * Check the remote host matches a list *
3299 *************************************************/
3301 /* This is a front end to verify_check_this_host(), created because checking
3302 the remote host is a common occurrence. With luck, a good compiler will spot
3303 the tail recursion and optimize it. If there's no host address, this is
3304 command-line SMTP input - check against an empty string for the address.
3307 listptr pointer to the host list
3309 Returns: the yield of verify_check_this_host(),
3310 i.e. OK, FAIL, or DEFER
3314 verify_check_host(uschar **listptr)
3316 return verify_check_this_host(listptr, sender_host_cache, NULL,
3317 (sender_host_address == NULL)? US"" : sender_host_address, NULL);
3324 /*************************************************
3325 * Invert an IP address *
3326 *************************************************/
3328 /* Originally just used for DNS xBL lists, now also used for the
3329 reverse_ip expansion operator.
3332 buffer where to put the answer
3333 address the address to invert
3337 invert_address(uschar *buffer, uschar *address)
3340 uschar *bptr = buffer;
3342 /* If this is an IPv4 address mapped into IPv6 format, adjust the pointer
3343 to the IPv4 part only. */
3345 if (Ustrncmp(address, "::ffff:", 7) == 0) address += 7;
3347 /* Handle IPv4 address: when HAVE_IPV6 is false, the result of host_aton() is
3350 if (host_aton(address, bin) == 1)
3354 for (i = 0; i < 4; i++)
3356 sprintf(CS bptr, "%d.", x & 255);
3357 while (*bptr) bptr++;
3362 /* Handle IPv6 address. Actually, as far as I know, there are no IPv6 addresses
3363 in any DNS black lists, and the format in which they will be looked up is
3364 unknown. This is just a guess. */
3370 for (j = 3; j >= 0; j--)
3373 for (i = 0; i < 8; i++)
3375 sprintf(CS bptr, "%x.", x & 15);
3376 while (*bptr) bptr++;
3383 /* Remove trailing period -- this is needed so that both arbitrary
3384 dnsbl keydomains and inverted addresses may be combined with the
3385 same format string, "%s.%s" */
3392 /*************************************************
3393 * Perform a single dnsbl lookup *
3394 *************************************************/
3396 /* This function is called from verify_check_dnsbl() below. It is also called
3397 recursively from within itself when domain and domain_txt are different
3398 pointers, in order to get the TXT record from the alternate domain.
3401 domain the outer dnsbl domain
3402 domain_txt alternate domain to lookup TXT record on success; when the
3403 same domain is to be used, domain_txt == domain (that is,
3404 the pointers must be identical, not just the text)
3405 keydomain the current keydomain (for debug message)
3406 prepend subdomain to lookup (like keydomain, but
3407 reversed if IP address)
3408 iplist the list of matching IP addresses, or NULL for "any"
3409 bitmask true if bitmask matching is wanted
3410 match_type condition for 'succeed' result
3411 0 => Any RR in iplist (=)
3412 1 => No RR in iplist (!=)
3413 2 => All RRs in iplist (==)
3414 3 => Some RRs not in iplist (!==)
3415 the two bits are defined as MT_NOT and MT_ALL
3416 defer_return what to return for a defer
3418 Returns: OK if lookup succeeded
3423 one_check_dnsbl(uschar *domain, uschar *domain_txt, uschar *keydomain,
3424 uschar *prepend, uschar *iplist, BOOL bitmask, int match_type,
3430 dnsbl_cache_block *cb;
3431 int old_pool = store_pool;
3432 uschar query[256]; /* DNS domain max length */
3434 /* Construct the specific query domainname */
3436 if (!string_format(query, sizeof(query), "%s.%s", prepend, domain))
3438 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
3439 "(ignored): %s...", query);
3443 /* Look for this query in the cache. */
3445 t = tree_search(dnsbl_cache, query);
3447 /* If not cached from a previous lookup, we must do a DNS lookup, and
3448 cache the result in permanent memory. */
3452 store_pool = POOL_PERM;
3454 /* Set up a tree entry to cache the lookup */
3456 t = store_get(sizeof(tree_node) + Ustrlen(query));
3457 Ustrcpy(t->name, query);
3458 t->data.ptr = cb = store_get(sizeof(dnsbl_cache_block));
3459 (void)tree_insertnode(&dnsbl_cache, t);
3461 /* Do the DNS loopup . */
3463 HDEBUG(D_dnsbl) debug_printf("new DNS lookup for %s\n", query);
3464 cb->rc = dns_basic_lookup(&dnsa, query, T_A);
3465 cb->text_set = FALSE;
3469 /* If the lookup succeeded, cache the RHS address. The code allows for
3470 more than one address - this was for complete generality and the possible
3471 use of A6 records. However, A6 records have been reduced to experimental
3472 status (August 2001) and may die out. So they may never get used at all,
3473 let alone in dnsbl records. However, leave the code here, just in case.
3475 Quite apart from one A6 RR generating multiple addresses, there are DNS
3476 lists that return more than one A record, so we must handle multiple
3477 addresses generated in that way as well. */
3479 if (cb->rc == DNS_SUCCEED)
3482 dns_address **addrp = &(cb->rhs);
3483 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
3485 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3487 if (rr->type == T_A)
3489 dns_address *da = dns_address_from_rr(&dnsa, rr);
3493 while (da->next != NULL) da = da->next;
3494 addrp = &(da->next);
3499 /* If we didn't find any A records, change the return code. This can
3500 happen when there is a CNAME record but there are no A records for what
3503 if (cb->rhs == NULL) cb->rc = DNS_NODATA;
3506 store_pool = old_pool;
3509 /* Previous lookup was cached */
3513 HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
3517 /* We now have the result of the DNS lookup, either newly done, or cached
3518 from a previous call. If the lookup succeeded, check against the address
3519 list if there is one. This may be a positive equality list (introduced by
3520 "="), a negative equality list (introduced by "!="), a positive bitmask
3521 list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/
3523 if (cb->rc == DNS_SUCCEED)
3525 dns_address *da = NULL;
3526 uschar *addlist = cb->rhs->address;
3528 /* For A and AAAA records, there may be multiple addresses from multiple
3529 records. For A6 records (currently not expected to be used) there may be
3530 multiple addresses from a single record. */
3532 for (da = cb->rhs->next; da != NULL; da = da->next)
3533 addlist = string_sprintf("%s, %s", addlist, da->address);
3535 HDEBUG(D_dnsbl) debug_printf("DNS lookup for %s succeeded (yielding %s)\n",
3538 /* Address list check; this can be either for equality, or via a bitmask.
3539 In the latter case, all the bits must match. */
3543 for (da = cb->rhs; da != NULL; da = da->next)
3547 uschar *ptr = iplist;
3550 /* Handle exact matching */
3554 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))) != NULL)
3556 if (Ustrcmp(CS da->address, ip) == 0) break;
3560 /* Handle bitmask matching */
3567 /* At present, all known DNS blocking lists use A records, with
3568 IPv4 addresses on the RHS encoding the information they return. I
3569 wonder if this will linger on as the last vestige of IPv4 when IPv6
3570 is ubiquitous? Anyway, for now we use paranoia code to completely
3571 ignore IPv6 addresses. The default mask is 0, which always matches.
3572 We change this only for IPv4 addresses in the list. */
3574 if (host_aton(da->address, address) == 1) mask = address[0];
3576 /* Scan the returned addresses, skipping any that are IPv6 */
3578 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))) != NULL)
3580 if (host_aton(ip, address) != 1) continue;
3581 if ((address[0] & mask) == address[0]) break;
3587 (a) An IP address in an any ('=') list matched, or
3588 (b) No IP address in an all ('==') list matched
3590 then we're done searching. */
3592 if (((match_type & MT_ALL) != 0) == (res == NULL)) break;
3595 /* If da == NULL, either
3597 (a) No IP address in an any ('=') list matched, or
3598 (b) An IP address in an all ('==') list didn't match
3600 so behave as if the DNSBL lookup had not succeeded, i.e. the host is not on
3603 if ((match_type == MT_NOT || match_type == MT_ALL) != (da == NULL))
3611 res = US"was no match";
3614 res = US"was an exclude match";
3617 res = US"was an IP address that did not match";
3620 res = US"were no IP addresses that did not match";
3623 debug_printf("=> but we are not accepting this block class because\n");
3624 debug_printf("=> there %s for %s%c%s\n",
3626 ((match_type & MT_ALL) == 0)? "" : "=",
3627 bitmask? '&' : '=', iplist);
3633 /* Either there was no IP list, or the record matched, implying that the
3634 domain is on the list. We now want to find a corresponding TXT record. If an
3635 alternate domain is specified for the TXT record, call this function
3636 recursively to look that up; this has the side effect of re-checking that
3637 there is indeed an A record at the alternate domain. */
3639 if (domain_txt != domain)
3640 return one_check_dnsbl(domain_txt, domain_txt, keydomain, prepend, NULL,
3641 FALSE, match_type, defer_return);
3643 /* If there is no alternate domain, look up a TXT record in the main domain
3644 if it has not previously been cached. */
3648 cb->text_set = TRUE;
3649 if (dns_basic_lookup(&dnsa, query, T_TXT) == DNS_SUCCEED)
3652 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
3654 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3655 if (rr->type == T_TXT) break;
3658 int len = (rr->data)[0];
3659 if (len > 511) len = 127;
3660 store_pool = POOL_PERM;
3661 cb->text = string_sprintf("%.*s", len, (const uschar *)(rr->data+1));
3662 store_pool = old_pool;
3667 dnslist_value = addlist;
3668 dnslist_text = cb->text;
3672 /* There was a problem with the DNS lookup */
3674 if (cb->rc != DNS_NOMATCH && cb->rc != DNS_NODATA)
3676 log_write(L_dnslist_defer, LOG_MAIN,
3677 "DNS list lookup defer (probably timeout) for %s: %s", query,
3678 (defer_return == OK)? US"assumed in list" :
3679 (defer_return == FAIL)? US"assumed not in list" :
3680 US"returned DEFER");
3681 return defer_return;
3684 /* No entry was found in the DNS; continue for next domain */
3688 debug_printf("DNS lookup for %s failed\n", query);
3689 debug_printf("=> that means %s is not listed at %s\n",
3699 /*************************************************
3700 * Check host against DNS black lists *
3701 *************************************************/
3703 /* This function runs checks against a list of DNS black lists, until one
3704 matches. Each item on the list can be of the form
3706 domain=ip-address/key
3708 The domain is the right-most domain that is used for the query, for example,
3709 blackholes.mail-abuse.org. If the IP address is present, there is a match only
3710 if the DNS lookup returns a matching IP address. Several addresses may be
3711 given, comma-separated, for example: x.y.z=127.0.0.1,127.0.0.2.
3713 If no key is given, what is looked up in the domain is the inverted IP address
3714 of the current client host. If a key is given, it is used to construct the
3715 domain for the lookup. For example:
3717 dsn.rfc-ignorant.org/$sender_address_domain
3719 After finding a match in the DNS, the domain is placed in $dnslist_domain, and
3720 then we check for a TXT record for an error message, and if found, save its
3721 value in $dnslist_text. We also cache everything in a tree, to optimize
3724 The TXT record is normally looked up in the same domain as the A record, but
3725 when many lists are combined in a single DNS domain, this will not be a very
3726 specific message. It is possible to specify a different domain for looking up
3727 TXT records; this is given before the main domain, comma-separated. For
3730 dnslists = http.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.2 : \
3731 socks.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.3
3733 The caching ensures that only one lookup in dnsbl.sorbs.net is done.
3735 Note: an address for testing RBL is 192.203.178.39
3736 Note: an address for testing DUL is 192.203.178.4
3737 Note: a domain for testing RFCI is example.tld.dsn.rfc-ignorant.org
3740 listptr the domain/address/data list
3742 Returns: OK successful lookup (i.e. the address is on the list), or
3743 lookup deferred after +include_unknown
3744 FAIL name not found, or no data found for the given type, or
3745 lookup deferred after +exclude_unknown (default)
3746 DEFER lookup failure, if +defer_unknown was set
3750 verify_check_dnsbl(uschar **listptr)
3753 int defer_return = FAIL;
3754 uschar *list = *listptr;
3757 uschar buffer[1024];
3758 uschar revadd[128]; /* Long enough for IPv6 address */
3760 /* Indicate that the inverted IP address is not yet set up */
3764 /* In case this is the first time the DNS resolver is being used. */
3766 dns_init(FALSE, FALSE, FALSE); /*XXX dnssec? */
3768 /* Loop through all the domains supplied, until something matches */
3770 while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
3773 BOOL bitmask = FALSE;
3780 HDEBUG(D_dnsbl) debug_printf("DNS list check: %s\n", domain);
3782 /* Deal with special values that change the behaviour on defer */
3784 if (domain[0] == '+')
3786 if (strcmpic(domain, US"+include_unknown") == 0) defer_return = OK;
3787 else if (strcmpic(domain, US"+exclude_unknown") == 0) defer_return = FAIL;
3788 else if (strcmpic(domain, US"+defer_unknown") == 0) defer_return = DEFER;
3790 log_write(0, LOG_MAIN|LOG_PANIC, "unknown item in dnslist (ignored): %s",
3795 /* See if there's explicit data to be looked up */
3797 key = Ustrchr(domain, '/');
3798 if (key != NULL) *key++ = 0;
3800 /* See if there's a list of addresses supplied after the domain name. This is
3801 introduced by an = or a & character; if preceded by = we require all matches
3802 and if preceded by ! we invert the result. */
3804 iplist = Ustrchr(domain, '=');
3808 iplist = Ustrchr(domain, '&');
3811 if (iplist != NULL) /* Found either = or & */
3813 if (iplist > domain && iplist[-1] == '!') /* Handle preceding ! */
3815 match_type |= MT_NOT;
3819 *iplist++ = 0; /* Terminate domain, move on */
3821 /* If we found = (bitmask == FALSE), check for == or =& */
3823 if (!bitmask && (*iplist == '=' || *iplist == '&'))
3825 bitmask = *iplist++ == '&';
3826 match_type |= MT_ALL;
3830 /* If there is a comma in the domain, it indicates that a second domain for
3831 looking up TXT records is provided, before the main domain. Otherwise we must
3832 set domain_txt == domain. */
3834 domain_txt = domain;
3835 comma = Ustrchr(domain, ',');
3842 /* Check that what we have left is a sensible domain name. There is no reason
3843 why these domains should in fact use the same syntax as hosts and email
3844 domains, but in practice they seem to. However, there is little point in
3845 actually causing an error here, because that would no doubt hold up incoming
3846 mail. Instead, I'll just log it. */
3848 for (s = domain; *s != 0; s++)
3850 if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_')
3852 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
3853 "strange characters - is this right?", domain);
3858 /* Check the alternate domain if present */
3860 if (domain_txt != domain) for (s = domain_txt; *s != 0; s++)
3862 if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_')
3864 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
3865 "strange characters - is this right?", domain_txt);
3870 /* If there is no key string, construct the query by adding the domain name
3871 onto the inverted host address, and perform a single DNS lookup. */
3875 if (sender_host_address == NULL) return FAIL; /* can never match */
3876 if (revadd[0] == 0) invert_address(revadd, sender_host_address);
3877 rc = one_check_dnsbl(domain, domain_txt, sender_host_address, revadd,
3878 iplist, bitmask, match_type, defer_return);
3881 dnslist_domain = string_copy(domain_txt);
3882 dnslist_matched = string_copy(sender_host_address);
3883 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
3884 sender_host_address, dnslist_domain);
3886 if (rc != FAIL) return rc; /* OK or DEFER */
3889 /* If there is a key string, it can be a list of domains or IP addresses to
3890 be concatenated with the main domain. */
3897 uschar keybuffer[256];
3898 uschar keyrevadd[128];
3900 while ((keydomain = string_nextinlist(&key, &keysep, keybuffer,
3901 sizeof(keybuffer))) != NULL)
3903 uschar *prepend = keydomain;
3905 if (string_is_ip_address(keydomain, NULL) != 0)
3907 invert_address(keyrevadd, keydomain);
3908 prepend = keyrevadd;
3911 rc = one_check_dnsbl(domain, domain_txt, keydomain, prepend, iplist,
3912 bitmask, match_type, defer_return);
3916 dnslist_domain = string_copy(domain_txt);
3917 dnslist_matched = string_copy(keydomain);
3918 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
3919 keydomain, dnslist_domain);
3923 /* If the lookup deferred, remember this fact. We keep trying the rest
3924 of the list to see if we get a useful result, and if we don't, we return
3925 DEFER at the end. */
3927 if (rc == DEFER) defer = TRUE;
3928 } /* continue with next keystring domain/address */
3930 if (defer) return DEFER;
3932 } /* continue with next dnsdb outer domain */
3939 /* End of verify.c */