1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2016 */
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 {
32 /* Anchor for DNSBL cache */
34 static tree_node *dnsbl_cache = NULL;
37 /* Bits for match_type in one_check_dnsbl() */
42 static uschar cutthrough_response(char, uschar **);
45 /*************************************************
46 * Retrieve a callout cache record *
47 *************************************************/
49 /* If a record exists, check whether it has expired.
52 dbm_file an open hints file
54 type "address" or "domain"
55 positive_expire expire time for positive records
56 negative_expire expire time for negative records
58 Returns: the cache record if a non-expired one exists, else NULL
61 static dbdata_callout_cache *
62 get_callout_cache_record(open_db *dbm_file, const uschar *key, uschar *type,
63 int positive_expire, int negative_expire)
68 dbdata_callout_cache *cache_record;
70 cache_record = dbfn_read_with_length(dbm_file, key, &length);
72 if (cache_record == NULL)
74 HDEBUG(D_verify) debug_printf("callout cache: no %s record found for %s\n", type, key);
78 /* We treat a record as "negative" if its result field is not positive, or if
79 it is a domain record and the postmaster field is negative. */
81 negative = cache_record->result != ccache_accept ||
82 (type[0] == 'd' && cache_record->postmaster_result == ccache_reject);
83 expire = negative? negative_expire : positive_expire;
86 if (now - cache_record->time_stamp > expire)
88 HDEBUG(D_verify) debug_printf("callout cache: %s record expired for %s\n", type, key);
92 /* If this is a non-reject domain record, check for the obsolete format version
93 that doesn't have the postmaster and random timestamps, by looking at the
94 length. If so, copy it to a new-style block, replicating the record's
95 timestamp. Then check the additional timestamps. (There's no point wasting
96 effort if connections are rejected.) */
98 if (type[0] == 'd' && cache_record->result != ccache_reject)
100 if (length == sizeof(dbdata_callout_cache_obs))
102 dbdata_callout_cache *new = store_get(sizeof(dbdata_callout_cache));
103 memcpy(new, cache_record, length);
104 new->postmaster_stamp = new->random_stamp = new->time_stamp;
108 if (now - cache_record->postmaster_stamp > expire)
109 cache_record->postmaster_result = ccache_unknown;
111 if (now - cache_record->random_stamp > expire)
112 cache_record->random_result = ccache_unknown;
115 HDEBUG(D_verify) debug_printf("callout cache: found %s record for %s\n", type, key);
121 /*************************************************
122 * Do callout verification for an address *
123 *************************************************/
125 /* This function is called from verify_address() when the address has routed to
126 a host list, and a callout has been requested. Callouts are expensive; that is
127 why a cache is used to improve the efficiency.
130 addr the address that's been routed
131 host_list the list of hosts to try
132 tf the transport feedback block
134 ifstring "interface" option from transport, or NULL
135 portstring "port" option from transport, or NULL
136 protocolstring "protocol" option from transport, or NULL
137 callout the per-command callout timeout
138 callout_overall the overall callout timeout (if < 0 use 4*callout)
139 callout_connect the callout connection timeout (if < 0 use callout)
140 options the verification options - these bits are used:
141 vopt_is_recipient => this is a recipient address
142 vopt_callout_no_cache => don't use callout cache
143 vopt_callout_fullpm => if postmaster check, do full one
144 vopt_callout_random => do the "random" thing
145 vopt_callout_recipsender => use real sender for recipient
146 vopt_callout_recippmaster => use postmaster for recipient
147 se_mailfrom MAIL FROM address for sender verify; NULL => ""
148 pm_mailfrom if non-NULL, do the postmaster check with this sender
150 Returns: OK/FAIL/DEFER
154 do_callout(address_item *addr, host_item *host_list, transport_feedback *tf,
155 int callout, int callout_overall, int callout_connect, int options,
156 uschar *se_mailfrom, uschar *pm_mailfrom)
159 int old_domain_cache_result = ccache_accept;
162 uschar *from_address;
163 uschar *random_local_part = NULL;
164 const uschar *save_deliver_domain = deliver_domain;
165 uschar **failure_ptr = options & vopt_is_recipient
166 ? &recipient_verify_failure : &sender_verify_failure;
168 open_db *dbm_file = NULL;
169 dbdata_callout_cache new_domain_record;
170 dbdata_callout_cache_address new_address_record;
172 time_t callout_start_time;
173 uschar peer_offered = 0;
175 new_domain_record.result = ccache_unknown;
176 new_domain_record.postmaster_result = ccache_unknown;
177 new_domain_record.random_result = ccache_unknown;
179 memset(&new_address_record, 0, sizeof(new_address_record));
181 /* For a recipient callout, the key used for the address cache record must
182 include the sender address if we are using the real sender in the callout,
183 because that may influence the result of the callout. */
185 address_key = addr->address;
188 if (options & vopt_is_recipient)
190 if (options & vopt_callout_recipsender)
192 address_key = string_sprintf("%s/<%s>", addr->address, sender_address);
193 from_address = sender_address;
194 if (cutthrough.delivery) options |= vopt_callout_no_cache;
196 else if (options & vopt_callout_recippmaster)
198 address_key = string_sprintf("%s/<postmaster@%s>", addr->address,
199 qualify_domain_sender);
200 from_address = string_sprintf("postmaster@%s", qualify_domain_sender);
204 /* For a sender callout, we must adjust the key if the mailfrom address is not
209 from_address = (se_mailfrom == NULL)? US"" : se_mailfrom;
210 if (from_address[0] != 0)
211 address_key = string_sprintf("%s/<%s>", addr->address, from_address);
214 /* Open the callout cache database, it it exists, for reading only at this
215 stage, unless caching has been disabled. */
217 if (options & vopt_callout_no_cache)
219 HDEBUG(D_verify) debug_printf("callout cache: disabled by no_cache\n");
221 else if ((dbm_file = dbfn_open(US"callout", O_RDWR, &dbblock, FALSE)) == NULL)
223 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
226 /* If a cache database is available see if we can avoid the need to do an
227 actual callout by making use of previously-obtained data. */
229 if (dbm_file != NULL)
231 dbdata_callout_cache_address *cache_address_record;
232 dbdata_callout_cache *cache_record = get_callout_cache_record(dbm_file,
233 addr->domain, US"domain",
234 callout_cache_domain_positive_expire,
235 callout_cache_domain_negative_expire);
237 /* If an unexpired cache record was found for this domain, see if the callout
238 process can be short-circuited. */
240 if (cache_record != NULL)
242 /* In most cases, if an early command (up to and including MAIL FROM:<>)
243 was rejected, there is no point carrying on. The callout fails. However, if
244 we are doing a recipient verification with use_sender or use_postmaster
245 set, a previous failure of MAIL FROM:<> doesn't count, because this time we
246 will be using a non-empty sender. We have to remember this situation so as
247 not to disturb the cached domain value if this whole verification succeeds
248 (we don't want it turning into "accept"). */
250 old_domain_cache_result = cache_record->result;
252 if (cache_record->result == ccache_reject ||
253 (*from_address == 0 && cache_record->result == ccache_reject_mfnull))
255 setflag(addr, af_verify_nsfail);
257 debug_printf("callout cache: domain gave initial rejection, or "
258 "does not accept HELO or MAIL FROM:<>\n");
259 setflag(addr, af_verify_nsfail);
260 addr->user_message = US"(result of an earlier callout reused).";
262 *failure_ptr = US"mail";
266 /* If a previous check on a "random" local part was accepted, we assume
267 that the server does not do any checking on local parts. There is therefore
268 no point in doing the callout, because it will always be successful. If a
269 random check previously failed, arrange not to do it again, but preserve
270 the data in the new record. If a random check is required but hasn't been
271 done, skip the remaining cache processing. */
273 if (options & vopt_callout_random) switch(cache_record->random_result)
277 debug_printf("callout cache: domain accepts random addresses\n");
278 goto END_CALLOUT; /* Default yield is OK */
282 debug_printf("callout cache: domain rejects random addresses\n");
283 options &= ~vopt_callout_random;
284 new_domain_record.random_result = ccache_reject;
285 new_domain_record.random_stamp = cache_record->random_stamp;
290 debug_printf("callout cache: need to check random address handling "
291 "(not cached or cache expired)\n");
295 /* If a postmaster check is requested, but there was a previous failure,
296 there is again no point in carrying on. If a postmaster check is required,
297 but has not been done before, we are going to have to do a callout, so skip
298 remaining cache processing. */
300 if (pm_mailfrom != NULL)
302 if (cache_record->postmaster_result == ccache_reject)
304 setflag(addr, af_verify_pmfail);
306 debug_printf("callout cache: domain does not accept "
307 "RCPT TO:<postmaster@domain>\n");
309 *failure_ptr = US"postmaster";
310 setflag(addr, af_verify_pmfail);
311 addr->user_message = US"(result of earlier verification reused).";
314 if (cache_record->postmaster_result == ccache_unknown)
317 debug_printf("callout cache: need to check RCPT "
318 "TO:<postmaster@domain> (not cached or cache expired)\n");
322 /* If cache says OK, set pm_mailfrom NULL to prevent a redundant
323 postmaster check if the address itself has to be checked. Also ensure
324 that the value in the cache record is preserved (with its old timestamp).
327 HDEBUG(D_verify) debug_printf("callout cache: domain accepts RCPT "
328 "TO:<postmaster@domain>\n");
330 new_domain_record.postmaster_result = ccache_accept;
331 new_domain_record.postmaster_stamp = cache_record->postmaster_stamp;
335 /* We can't give a result based on information about the domain. See if there
336 is an unexpired cache record for this specific address (combined with the
337 sender address if we are doing a recipient callout with a non-empty sender).
340 cache_address_record = (dbdata_callout_cache_address *)
341 get_callout_cache_record(dbm_file,
342 address_key, US"address",
343 callout_cache_positive_expire,
344 callout_cache_negative_expire);
346 if (cache_address_record != NULL)
348 if (cache_address_record->result == ccache_accept)
351 debug_printf("callout cache: address record is positive\n");
356 debug_printf("callout cache: address record is negative\n");
357 addr->user_message = US"Previous (cached) callout verification failure";
358 *failure_ptr = US"recipient";
364 /* Close the cache database while we actually do the callout for real. */
367 dbfn_close(dbm_file);
371 if (!addr->transport)
373 HDEBUG(D_verify) debug_printf("cannot callout via null transport\n");
375 else if (Ustrcmp(addr->transport->driver_name, "smtp") != 0)
376 log_write(0, LOG_MAIN|LOG_PANIC|LOG_CONFIG_FOR, "callout transport '%s': %s is non-smtp",
377 addr->transport->name, addr->transport->driver_name);
380 smtp_transport_options_block *ob =
381 (smtp_transport_options_block *)addr->transport->options_block;
383 /* The information wasn't available in the cache, so we have to do a real
384 callout and save the result in the cache for next time, unless no_cache is set,
385 or unless we have a previously cached negative random result. If we are to test
386 with a random local part, ensure that such a local part is available. If not,
387 log the fact, but carry on without randomming. */
389 if (options & vopt_callout_random && callout_random_local_part != NULL)
390 if (!(random_local_part = expand_string(callout_random_local_part)))
391 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand "
392 "callout_random_local_part: %s", expand_string_message);
394 /* Default the connect and overall callout timeouts if not set, and record the
395 time we are starting so that we can enforce it. */
397 if (callout_overall < 0) callout_overall = 4 * callout;
398 if (callout_connect < 0) callout_connect = callout;
399 callout_start_time = time(NULL);
401 /* Before doing a real callout, if this is an SMTP connection, flush the SMTP
402 output because a callout might take some time. When PIPELINING is active and
403 there are many recipients, the total time for doing lots of callouts can add up
404 and cause the client to time out. So in this case we forgo the PIPELINING
407 if (smtp_out != NULL && !disable_callout_flush) mac_smtp_fflush();
409 /* cutthrough-multi: if a nonfirst rcpt has the same routing as the first,
410 and we are holding a cutthrough conn open, we can just append the rcpt to
411 that conn for verification purposes (and later delivery also). Simplest
412 coding means skipping this whole loop and doing the append separately.
414 We will need to remember it has been appended so that rcpt-acl tail code
415 can do it there for the non-rcpt-verify case. For this we keep an addresscount.
418 /* Can we re-use an open cutthrough connection? */
419 if ( cutthrough.fd >= 0
420 && (options & (vopt_callout_recipsender | vopt_callout_recippmaster))
421 == vopt_callout_recipsender
422 && !random_local_part
426 if (addr->transport == cutthrough.addr.transport)
427 for (host = host_list; host; host = host->next)
428 if (Ustrcmp(host->address, cutthrough.host.address) == 0)
431 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
434 deliver_host = host->name;
435 deliver_host_address = host->address;
436 deliver_host_port = host->port;
437 deliver_domain = addr->domain;
438 transport_name = addr->transport->name;
440 host_af = (Ustrchr(host->address, ':') == NULL)? AF_INET:AF_INET6;
442 if (!smtp_get_interface(tf->interface, host_af, addr, &interface,
444 !smtp_get_port(tf->port, addr, &port, US"callout"))
445 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
448 if ( ( interface == cutthrough.interface
450 && cutthrough.interface
451 && Ustrcmp(interface, cutthrough.interface) == 0
453 && port == cutthrough.host.port
456 uschar * resp = NULL;
458 /* Match! Send the RCPT TO, append the addr, set done */
460 smtp_write_command(&ctblock, FALSE, "RCPT TO:<%.1000s>\r\n",
461 transport_rcpt_address(addr,
462 (addr->transport == NULL)? FALSE :
463 addr->transport->rcpt_include_affixes)) >= 0 &&
464 cutthrough_response('2', &resp) == '2';
466 /* This would go horribly wrong if a callout fail was ignored by ACL.
467 We punt by abandoning cutthrough on a reject, like the
472 address_item * na = store_get(sizeof(address_item));
473 *na = cutthrough.addr;
474 cutthrough.addr = *addr;
475 cutthrough.addr.host_used = &cutthrough.host;
476 cutthrough.addr.next = na;
482 cancel_cutthrough_connection("recipient rejected");
483 if (!resp || errno == ETIMEDOUT)
485 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
490 Ustrcpy(resp, US"connection dropped");
493 string_sprintf("response to \"%s\" from %s [%s] was: %s",
494 big_buffer, host->name, host->address,
495 string_printing(resp));
498 string_sprintf("Callout verification failed:\n%s", resp);
500 /* Hard rejection ends the process */
502 if (resp[0] == '5') /* Address rejected */
513 cancel_cutthrough_connection("incompatible connection");
516 /* Now make connections to the hosts and do real callouts. The list of hosts
517 is passed in as an argument. */
519 for (host = host_list; host != NULL && !done; host = host->next)
521 smtp_inblock inblock;
522 smtp_outblock outblock;
525 BOOL send_quit = TRUE;
526 uschar *active_hostname = smtp_active_hostname;
530 BOOL suppress_tls = FALSE;
531 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
532 #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_DANE)
535 dns_answer tlsa_dnsa;
537 uschar inbuffer[4096];
538 uschar outbuffer[1024];
539 uschar responsebuffer[4096];
542 clearflag(addr, af_verify_pmfail); /* postmaster callout flag */
543 clearflag(addr, af_verify_nsfail); /* null sender callout flag */
545 /* Skip this host if we don't have an IP address for it. */
547 if (host->address == NULL)
549 DEBUG(D_verify) debug_printf("no IP address for host name %s: skipping\n",
554 /* Check the overall callout timeout */
556 if (time(NULL) - callout_start_time >= callout_overall)
558 HDEBUG(D_verify) debug_printf("overall timeout for callout exceeded\n");
562 /* Set IPv4 or IPv6 */
564 host_af = (Ustrchr(host->address, ':') == NULL)? AF_INET:AF_INET6;
566 /* Expand and interpret the interface and port strings. The latter will not
567 be used if there is a host-specific port (e.g. from a manualroute router).
568 This has to be delayed till now, because they may expand differently for
569 different hosts. If there's a failure, log it, but carry on with the
572 deliver_host = host->name;
573 deliver_host_address = host->address;
574 deliver_host_port = host->port;
575 deliver_domain = addr->domain;
576 transport_name = addr->transport->name;
578 if ( !smtp_get_interface(tf->interface, host_af, addr, &interface,
580 || !smtp_get_port(tf->port, addr, &port, US"callout")
582 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
585 /* Set HELO string according to the protocol */
586 lmtp= Ustrcmp(tf->protocol, "lmtp") == 0;
587 smtps= Ustrcmp(tf->protocol, "smtps") == 0;
590 HDEBUG(D_verify) debug_printf("interface=%s port=%d\n", interface, port);
592 /* Set up the buffer for reading SMTP response packets. */
594 inblock.buffer = inbuffer;
595 inblock.buffersize = sizeof(inbuffer);
596 inblock.ptr = inbuffer;
597 inblock.ptrend = inbuffer;
599 /* Set up the buffer for holding SMTP commands while pipelining */
601 outblock.buffer = outbuffer;
602 outblock.buffersize = sizeof(outbuffer);
603 outblock.ptr = outbuffer;
604 outblock.cmd_count = 0;
605 outblock.authenticating = FALSE;
607 /* Connect to the host; on failure, just loop for the next one, but we
608 set the error for the last one. Use the callout_connect timeout. */
610 tls_retry_connection:
612 /* Reset the parameters of a TLS session */
613 tls_out.cipher = tls_out.peerdn = tls_out.peercert = NULL;
615 inblock.sock = outblock.sock =
616 smtp_connect(host, host_af, port, interface, callout_connect,
618 if (inblock.sock < 0)
620 addr->message = string_sprintf("could not connect to %s [%s]: %s",
621 host->name, host->address, strerror(errno));
622 transport_name = NULL;
623 deliver_host = deliver_host_address = NULL;
624 deliver_domain = save_deliver_domain;
628 #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_DANE)
632 tls_out.dane_verified = FALSE;
633 tls_out.tlsa_usage = 0;
636 verify_check_given_host(&ob->hosts_require_dane, host) == OK;
638 if (host->dnssec == DS_YES)
641 || verify_check_given_host(&ob->hosts_try_dane, host) == OK
644 if ((rc = tlsa_lookup(host, &tlsa_dnsa, dane_required)) != OK)
649 else if (dane_required)
651 log_write(0, LOG_MAIN, "DANE error: %s lookup not DNSSEC", host->name);
656 ob->tls_tempfail_tryclear = FALSE;
660 /* Expand the helo_data string to find the host name to use. */
662 if (tf->helo_data != NULL)
664 uschar *s = expand_string(tf->helo_data);
666 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: failed to expand transport's "
667 "helo_data value for callout: %s", addr->address,
668 expand_string_message);
669 else active_hostname = s;
672 /* Wait for initial response, and send HELO. The smtp_write_command()
673 function leaves its command in big_buffer. This is used in error responses.
674 Initialize it in case the connection is rejected. */
676 Ustrcpy(big_buffer, "initial connection");
678 /* Unless ssl-on-connect, wait for the initial greeting */
682 if (!smtps || (smtps && tls_out.active >= 0))
685 if (!(done= smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), '2', callout)))
686 goto RESPONSE_FAILED;
688 #ifndef DISABLE_EVENT
689 lookup_dnssec_authenticated = host->dnssec==DS_YES ? US"yes"
690 : host->dnssec==DS_NO ? US"no" : NULL;
691 if (event_raise(addr->transport->event_action,
692 US"smtp:connect", responsebuffer))
694 lookup_dnssec_authenticated = NULL;
695 /* Logging? Debug? */
696 goto RESPONSE_FAILED;
698 lookup_dnssec_authenticated = NULL;
702 /* Not worth checking greeting line for ESMTP support */
703 if (!(esmtp = verify_check_given_host(&ob->hosts_avoid_esmtp, host) != OK))
705 debug_printf("not sending EHLO (host matches hosts_avoid_esmtp)\n");
710 if (smtps && tls_out.active < 0) /* ssl-on-connect, first pass */
712 peer_offered &= ~PEER_OFFERED_TLS;
713 ob->tls_tempfail_tryclear = FALSE;
715 else /* all other cases */
720 if (!(done= smtp_write_command(&outblock, FALSE, "%s %s\r\n",
721 !esmtp? "HELO" : lmtp? "LHLO" : "EHLO", active_hostname) >= 0))
723 if (!smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), '2', callout))
725 if (errno != 0 || responsebuffer[0] == 0 || lmtp || !esmtp || tls_out.active >= 0)
728 goto RESPONSE_FAILED;
731 peer_offered &= ~PEER_OFFERED_TLS;
734 goto esmtp_retry; /* fallback to HELO */
737 /* Set tls_offered if the response to EHLO specifies support for STARTTLS. */
740 ? ehlo_response(responsebuffer, sizeof(responsebuffer),
741 (!suppress_tls && tls_out.active < 0 ? PEER_OFFERED_TLS : 0)
745 | (addr->prop.utf8_msg && !addr->prop.utf8_downcvt
746 ? PEER_OFFERED_UTF8 : 0)
751 /* only care about SIZE if we have size from inbound */
752 | (message_size > 0 && ob->size_addition >= 0
753 ? PEER_OFFERED_SIZE : 0)
758 size_str = peer_offered & PEER_OFFERED_SIZE
759 ? string_sprintf(" SIZE=%d", message_size + ob->size_addition) : US"";
762 smtp_peer_options |= peer_offered & PEER_OFFERED_TLS;
765 /* If TLS is available on this connection attempt to
766 start up a TLS session, unless the host is in hosts_avoid_tls. If successful,
767 send another EHLO - the server may give a different answer in secure mode. We
768 use a separate buffer for reading the response to STARTTLS so that if it is
769 negative, the original EHLO data is available for subsequent analysis, should
770 the client not be required to use TLS. If the response is bad, copy the buffer
771 for error analysis. */
774 if ( peer_offered & PEER_OFFERED_TLS
775 && verify_check_given_host(&ob->hosts_avoid_tls, host) != OK
776 && verify_check_given_host(&ob->hosts_verify_avoid_tls, host) != OK
779 uschar buffer2[4096];
781 && !(done= smtp_write_command(&outblock, FALSE, "STARTTLS\r\n") >= 0))
784 /* If there is an I/O error, transmission of this message is deferred. If
785 there is a temporary rejection of STARRTLS and tls_tempfail_tryclear is
786 false, we also defer. However, if there is a temporary rejection of STARTTLS
787 and tls_tempfail_tryclear is true, or if there is an outright rejection of
788 STARTTLS, we carry on. This means we will try to send the message in clear,
789 unless the host is in hosts_require_tls (tested below). */
791 if (!smtps && !smtp_read_response(&inblock, buffer2, sizeof(buffer2), '2',
792 ob->command_timeout))
796 || buffer2[0] == '4' && !ob->tls_tempfail_tryclear
799 Ustrncpy(responsebuffer, buffer2, sizeof(responsebuffer));
801 goto RESPONSE_FAILED;
805 /* STARTTLS accepted or ssl-on-connect: try to negotiate a TLS session. */
808 int oldtimeout = ob->command_timeout;
812 ob->command_timeout = callout;
813 rc = tls_client_start(inblock.sock, host, addr, addr->transport
814 # ifdef EXPERIMENTAL_DANE
815 , dane ? &tlsa_dnsa : NULL
818 ob->command_timeout = oldtimeout;
820 /* TLS negotiation failed; give an error. Try in clear on a new
821 connection, if the options permit it for this host. */
826 (void)close(inblock.sock);
827 # ifndef DISABLE_EVENT
828 (void) event_raise(addr->transport->event_action,
829 US"tcp:close", NULL);
831 if ( ob->tls_tempfail_tryclear
833 && verify_check_given_host(&ob->hosts_require_tls, host) != OK
836 log_write(0, LOG_MAIN, "TLS session failure:"
837 " delivering unencrypted to %s [%s] (not in hosts_require_tls)",
838 host->name, host->address);
840 goto tls_retry_connection;
844 /*save_errno = ERRNO_TLSFAILURE;*/
845 /*message = US"failure while setting up TLS session";*/
851 /* TLS session is set up. Copy info for logging. */
852 addr->cipher = tls_out.cipher;
853 addr->peerdn = tls_out.peerdn;
855 /* For SMTPS we need to wait for the initial OK response, then do HELO. */
857 goto smtps_redo_greeting;
859 /* For STARTTLS we need to redo EHLO */
864 /* If the host is required to use a secure channel, ensure that we have one. */
865 if (tls_out.active < 0)
867 # ifdef EXPERIMENTAL_DANE
870 verify_check_given_host(&ob->hosts_require_tls, host) == OK
873 /*save_errno = ERRNO_TLSREQUIRED;*/
874 log_write(0, LOG_MAIN,
875 "H=%s [%s]: a TLS session is required for this host, but %s",
876 host->name, host->address,
877 peer_offered & PEER_OFFERED_TLS
878 ? "an attempt to start TLS failed"
879 : "the server did not offer TLS support");
884 #endif /*SUPPORT_TLS*/
886 done = TRUE; /* so far so good; have response to HELO */
888 /* For now, transport_filter by cutthrough-delivery is not supported */
889 /* Need proper integration with the proper transport mechanism. */
890 if (cutthrough.delivery)
895 if (addr->transport->filter_command)
897 cutthrough.delivery = FALSE;
898 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of transport filter\n");
901 else if ((s = ob->dkim.dkim_domain) && (s = expand_string(s)) && *s)
903 cutthrough.delivery = FALSE;
904 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of DKIM signing\n");
913 /* Clear down of the TLS, SMTP and TCP layers on error is handled below. */
915 /* Failure to accept HELO is cached; this blocks the whole domain for all
916 senders. I/O errors and defer responses are not cached. */
920 *failure_ptr = US"mail"; /* At or before MAIL */
921 if (errno == 0 && responsebuffer[0] == '5')
923 setflag(addr, af_verify_nsfail);
924 new_domain_record.result = ccache_reject;
929 else if ( addr->prop.utf8_msg
930 && !addr->prop.utf8_downcvt
931 && !(peer_offered & PEER_OFFERED_UTF8)
934 HDEBUG(D_acl|D_v) debug_printf("utf8 required but not offered\n");
935 errno = ERRNO_UTF8_FWD;
936 setflag(addr, af_verify_nsfail);
939 else if ( addr->prop.utf8_msg
940 && (addr->prop.utf8_downcvt || !(peer_offered & PEER_OFFERED_UTF8))
941 && (setflag(addr, af_utf8_downcvt),
942 from_address = string_address_utf8_to_alabel(from_address,
947 errno = ERRNO_EXPANDFAIL;
948 setflag(addr, af_verify_nsfail);
953 /* If we haven't authenticated, but are required to, give up. */
956 else done = smtp_auth(responsebuffer, sizeof(responsebuffer),
957 addr, host, ob, esmtp, &inblock, &outblock) == OK &&
959 /* Copy AUTH info for logging */
960 ( (addr->authenticator = client_authenticator),
961 (addr->auth_id = client_authenticated_id),
963 /* Build a mail-AUTH string (re-using responsebuffer for convenience */
964 !smtp_mail_auth_str(responsebuffer, sizeof(responsebuffer), addr, ob)
967 ( (addr->auth_sndr = client_authenticated_sender),
969 /* Send the MAIL command */
970 (smtp_write_command(&outblock, FALSE,
972 addr->prop.utf8_msg && !addr->prop.utf8_downcvt
973 ? "MAIL FROM:<%s>%s%s SMTPUTF8\r\n"
976 "MAIL FROM:<%s>%s%s\r\n",
977 from_address, responsebuffer, size_str) >= 0)
980 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
983 deliver_host = deliver_host_address = NULL;
984 deliver_domain = save_deliver_domain;
986 /* If the host does not accept MAIL FROM:<>, arrange to cache this
987 information, but again, don't record anything for an I/O error or a defer. Do
988 not cache rejections of MAIL when a non-empty sender has been used, because
989 that blocks the whole domain for all senders. */
993 *failure_ptr = US"mail"; /* At or before MAIL */
994 if (errno == 0 && responsebuffer[0] == '5')
996 setflag(addr, af_verify_nsfail);
997 if (from_address[0] == 0)
998 new_domain_record.result = ccache_reject_mfnull;
1002 /* Otherwise, proceed to check a "random" address (if required), then the
1003 given address, and the postmaster address (if required). Between each check,
1004 issue RSET, because some servers accept only one recipient after MAIL
1007 Before doing this, set the result in the domain cache record to "accept",
1008 unless its previous value was ccache_reject_mfnull. In that case, the domain
1009 rejects MAIL FROM:<> and we want to continue to remember that. When that is
1010 the case, we have got here only in the case of a recipient verification with
1011 a non-null sender. */
1015 const uschar * rcpt_domain = addr->domain;
1018 uschar * errstr = NULL;
1019 if ( testflag(addr, af_utf8_downcvt)
1020 && (rcpt_domain = string_domain_utf8_to_alabel(rcpt_domain,
1024 addr->message = errstr;
1025 errno = ERRNO_EXPANDFAIL;
1026 setflag(addr, af_verify_nsfail);
1028 rcpt_domain = US""; /*XXX errorhandling! */
1032 new_domain_record.result =
1033 (old_domain_cache_result == ccache_reject_mfnull)?
1034 ccache_reject_mfnull: ccache_accept;
1036 /* Do the random local part check first */
1038 if (random_local_part != NULL)
1040 uschar randombuffer[1024];
1042 smtp_write_command(&outblock, FALSE,
1043 "RCPT TO:<%.1000s@%.1000s>\r\n", random_local_part,
1044 rcpt_domain) >= 0 &&
1045 smtp_read_response(&inblock, randombuffer,
1046 sizeof(randombuffer), '2', callout);
1048 /* Remember when we last did a random test */
1050 new_domain_record.random_stamp = time(NULL);
1052 /* If accepted, we aren't going to do any further tests below. */
1055 new_domain_record.random_result = ccache_accept;
1057 /* Otherwise, cache a real negative response, and get back to the right
1058 state to send RCPT. Unless there's some problem such as a dropped
1059 connection, we expect to succeed, because the commands succeeded above.
1060 However, some servers drop the connection after responding to an
1061 invalid recipient, so on (any) error we drop and remake the connection.
1064 else if (errno == 0)
1066 /* This would be ok for 1st rcpt a cutthrough, but no way to
1067 handle a subsequent. So refuse to support any */
1068 cancel_cutthrough_connection("random-recipient");
1070 if (randombuffer[0] == '5')
1071 new_domain_record.random_result = ccache_reject;
1074 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
1075 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
1078 smtp_write_command(&outblock, FALSE,
1080 addr->prop.utf8_msg && !addr->prop.utf8_downcvt
1081 ? "MAIL FROM:<%s> SMTPUTF8\r\n"
1084 "MAIL FROM:<%s>\r\n",
1085 from_address) >= 0 &&
1086 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
1092 debug_printf("problem after random/rset/mfrom; reopen conn\n");
1093 random_local_part = NULL;
1095 tls_close(FALSE, TRUE);
1097 (void)close(inblock.sock);
1098 #ifndef DISABLE_EVENT
1099 (void) event_raise(addr->transport->event_action,
1100 US"tcp:close", NULL);
1102 goto tls_retry_connection;
1105 else done = FALSE; /* Some timeout/connection problem */
1106 } /* Random check */
1108 /* If the host is accepting all local parts, as determined by the "random"
1109 check, we don't need to waste time doing any further checking. */
1111 if (new_domain_record.random_result != ccache_accept && done)
1113 /* Get the rcpt_include_affixes flag from the transport if there is one,
1114 but assume FALSE if there is not. */
1116 uschar * rcpt = transport_rcpt_address(addr,
1117 addr->transport ? addr->transport->rcpt_include_affixes : FALSE);
1120 /*XXX should the conversion be moved into transport_rcpt_address() ? */
1121 uschar * dummy_errstr = NULL;
1122 if ( testflag(addr, af_utf8_downcvt)
1123 && (rcpt = string_address_utf8_to_alabel(rcpt, &dummy_errstr),
1127 errno = ERRNO_EXPANDFAIL;
1128 *failure_ptr = US"recipient";
1135 smtp_write_command(&outblock, FALSE, "RCPT TO:<%.1000s>\r\n",
1137 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
1141 new_address_record.result = ccache_accept;
1142 else if (errno == 0 && responsebuffer[0] == '5')
1144 *failure_ptr = US"recipient";
1145 new_address_record.result = ccache_reject;
1148 /* Do postmaster check if requested; if a full check is required, we
1149 check for RCPT TO:<postmaster> (no domain) in accordance with RFC 821. */
1151 if (done && pm_mailfrom != NULL)
1153 /* Could possibly shift before main verify, just above, and be ok
1154 for cutthrough. But no way to handle a subsequent rcpt, so just
1156 cancel_cutthrough_connection("postmaster verify");
1157 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of postmaster verify\n");
1160 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
1161 smtp_read_response(&inblock, responsebuffer,
1162 sizeof(responsebuffer), '2', callout) &&
1164 smtp_write_command(&outblock, FALSE,
1165 "MAIL FROM:<%s>\r\n", pm_mailfrom) >= 0 &&
1166 smtp_read_response(&inblock, responsebuffer,
1167 sizeof(responsebuffer), '2', callout) &&
1169 /* First try using the current domain */
1172 smtp_write_command(&outblock, FALSE,
1173 "RCPT TO:<postmaster@%.1000s>\r\n", rcpt_domain) >= 0 &&
1174 smtp_read_response(&inblock, responsebuffer,
1175 sizeof(responsebuffer), '2', callout)
1180 /* If that doesn't work, and a full check is requested,
1181 try without the domain. */
1184 (options & vopt_callout_fullpm) != 0 &&
1185 smtp_write_command(&outblock, FALSE,
1186 "RCPT TO:<postmaster>\r\n") >= 0 &&
1187 smtp_read_response(&inblock, responsebuffer,
1188 sizeof(responsebuffer), '2', callout)
1191 /* Sort out the cache record */
1193 new_domain_record.postmaster_stamp = time(NULL);
1196 new_domain_record.postmaster_result = ccache_accept;
1197 else if (errno == 0 && responsebuffer[0] == '5')
1199 *failure_ptr = US"postmaster";
1200 setflag(addr, af_verify_pmfail);
1201 new_domain_record.postmaster_result = ccache_reject;
1204 } /* Random not accepted */
1205 } /* MAIL FROM: accepted */
1207 /* For any failure of the main check, other than a negative response, we just
1208 close the connection and carry on. We can identify a negative response by the
1209 fact that errno is zero. For I/O errors it will be non-zero
1211 Set up different error texts for logging and for sending back to the caller
1212 as an SMTP response. Log in all cases, using a one-line format. For sender
1213 callouts, give a full response to the caller, but for recipient callouts,
1214 don't give the IP address because this may be an internal host whose identity
1215 is not to be widely broadcast. */
1219 if (errno == ETIMEDOUT)
1221 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
1225 else if (errno == ERRNO_UTF8_FWD)
1227 extern int acl_where; /* src/acl.c */
1229 addr->message = string_sprintf(
1230 "response to \"%s\" from %s [%s] did not include SMTPUTF8",
1231 big_buffer, host->name, host->address);
1232 addr->user_message = acl_where == ACL_WHERE_RCPT
1233 ? US"533 mailbox name not allowed"
1234 : US"550 mailbox unavailable";
1239 else if (errno == 0)
1241 if (*responsebuffer == 0) Ustrcpy(responsebuffer, US"connection dropped");
1244 string_sprintf("response to \"%s\" from %s [%s] was: %s",
1245 big_buffer, host->name, host->address,
1246 string_printing(responsebuffer));
1248 addr->user_message = options & vopt_is_recipient
1249 ? string_sprintf("Callout verification failed:\n%s", responsebuffer)
1250 : string_sprintf("Called: %s\nSent: %s\nResponse: %s",
1251 host->address, big_buffer, responsebuffer);
1253 /* Hard rejection ends the process */
1255 if (responsebuffer[0] == '5') /* Address rejected */
1263 /* End the SMTP conversation and close the connection. */
1265 /* Cutthrough - on a successfull connect and recipient-verify with
1266 use-sender and we are 1st rcpt and have no cutthrough conn so far
1267 here is where we want to leave the conn open */
1268 if ( cutthrough.delivery
1272 && (options & (vopt_callout_recipsender|vopt_callout_recippmaster|vopt_success_on_redirect))
1273 == vopt_callout_recipsender
1274 && !random_local_part
1276 && cutthrough.fd < 0
1280 HDEBUG(D_acl|D_v) debug_printf("holding verify callout open for cutthrough delivery\n");
1282 cutthrough.fd = outblock.sock; /* We assume no buffer in use in the outblock */
1283 cutthrough.nrcpt = 1;
1284 cutthrough.interface = interface;
1285 cutthrough.host = *host;
1286 cutthrough.addr = *addr; /* Save the address_item for later logging */
1287 cutthrough.addr.next = NULL;
1288 cutthrough.addr.host_used = &cutthrough.host;
1290 *(cutthrough.addr.parent = store_get(sizeof(address_item))) =
1292 ctblock.buffer = ctbuffer;
1293 ctblock.buffersize = sizeof(ctbuffer);
1294 ctblock.ptr = ctbuffer;
1295 /* ctblock.cmd_count = 0; ctblock.authenticating = FALSE; */
1296 ctblock.sock = cutthrough.fd;
1300 /* Ensure no cutthrough on multiple address verifies */
1301 if (options & vopt_callout_recipsender)
1302 cancel_cutthrough_connection("multiple verify calls");
1303 if (send_quit) (void)smtp_write_command(&outblock, FALSE, "QUIT\r\n");
1306 tls_close(FALSE, TRUE);
1308 (void)close(inblock.sock);
1309 #ifndef DISABLE_EVENT
1310 (void) event_raise(addr->transport->event_action, US"tcp:close", NULL);
1314 } /* Loop through all hosts, while !done */
1317 /* If we get here with done == TRUE, a successful callout happened, and yield
1318 will be set OK or FAIL according to the response to the RCPT command.
1319 Otherwise, we looped through the hosts but couldn't complete the business.
1320 However, there may be domain-specific information to cache in both cases.
1322 The value of the result field in the new_domain record is ccache_unknown if
1323 there was an error before or with MAIL FROM:, and errno was not zero,
1324 implying some kind of I/O error. We don't want to write the cache in that case.
1325 Otherwise the value is ccache_accept, ccache_reject, or ccache_reject_mfnull. */
1327 if ( !(options & vopt_callout_no_cache)
1328 && new_domain_record.result != ccache_unknown)
1330 if ((dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE))
1333 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
1337 (void)dbfn_write(dbm_file, addr->domain, &new_domain_record,
1338 (int)sizeof(dbdata_callout_cache));
1339 HDEBUG(D_verify) debug_printf("wrote callout cache domain record for %s:\n"
1340 " result=%d postmaster=%d random=%d\n",
1342 new_domain_record.result,
1343 new_domain_record.postmaster_result,
1344 new_domain_record.random_result);
1348 /* If a definite result was obtained for the callout, cache it unless caching
1353 if ( !(options & vopt_callout_no_cache)
1354 && new_address_record.result != ccache_unknown)
1356 if (dbm_file == NULL)
1357 dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE);
1358 if (dbm_file == NULL)
1360 HDEBUG(D_verify) debug_printf("no callout cache available\n");
1364 (void)dbfn_write(dbm_file, address_key, &new_address_record,
1365 (int)sizeof(dbdata_callout_cache_address));
1366 HDEBUG(D_verify) debug_printf("wrote %s callout cache address record for %s\n",
1367 new_address_record.result == ccache_accept ? "positive" : "negative",
1373 /* Failure to connect to any host, or any response other than 2xx or 5xx is a
1374 temporary error. If there was only one host, and a response was received, leave
1375 it alone if supplying details. Otherwise, give a generic response. */
1379 uschar *dullmsg = string_sprintf("Could not complete %s verify callout",
1380 options & vopt_is_recipient ? "recipient" : "sender");
1383 if (host_list->next != NULL || addr->message == NULL) addr->message = dullmsg;
1385 addr->user_message = (!smtp_return_error_details)? dullmsg :
1386 string_sprintf("%s for <%s>.\n"
1387 "The mail server(s) for the domain may be temporarily unreachable, or\n"
1388 "they may be permanently unreachable from this server. In the latter case,\n%s",
1389 dullmsg, addr->address,
1390 options & vopt_is_recipient
1391 ? "the address will never be accepted."
1392 : "you need to change the address or create an MX record for its domain\n"
1393 "if it is supposed to be generally accessible from the Internet.\n"
1394 "Talk to your mail administrator for details.");
1396 /* Force a specific error code */
1398 addr->basic_errno = ERRNO_CALLOUTDEFER;
1401 /* Come here from within the cache-reading code on fast-track exit. */
1404 if (dbm_file != NULL) dbfn_close(dbm_file);
1410 /* Called after recipient-acl to get a cutthrough connection open when
1411 one was requested and a recipient-verify wasn't subsequently done.
1414 open_cutthrough_connection( address_item * addr )
1419 /* Use a recipient-verify-callout to set up the cutthrough connection. */
1420 /* We must use a copy of the address for verification, because it might
1424 HDEBUG(D_acl) debug_printf("----------- %s cutthrough setup ------------\n",
1425 rcpt_count > 1 ? "more" : "start");
1426 rc= verify_address(&addr2, NULL,
1427 vopt_is_recipient | vopt_callout_recipsender | vopt_callout_no_cache,
1428 CUTTHROUGH_CMD_TIMEOUT, -1, -1,
1430 HDEBUG(D_acl) debug_printf("----------- end cutthrough setup ------------\n");
1436 /* Send given number of bytes from the buffer */
1438 cutthrough_send(int n)
1440 if(cutthrough.fd < 0)
1445 (tls_out.active == cutthrough.fd) ? tls_write(FALSE, ctblock.buffer, n) :
1447 send(cutthrough.fd, ctblock.buffer, n, 0) > 0
1450 transport_count += n;
1451 ctblock.ptr= ctblock.buffer;
1455 HDEBUG(D_transport|D_acl) debug_printf("cutthrough_send failed: %s\n", strerror(errno));
1462 _cutthrough_puts(uschar * cp, int n)
1466 if(ctblock.ptr >= ctblock.buffer+ctblock.buffersize)
1467 if(!cutthrough_send(ctblock.buffersize))
1470 *ctblock.ptr++ = *cp++;
1475 /* Buffered output of counted data block. Return boolean success */
1477 cutthrough_puts(uschar * cp, int n)
1479 if (cutthrough.fd < 0) return TRUE;
1480 if (_cutthrough_puts(cp, n)) return TRUE;
1481 cancel_cutthrough_connection("transmit failed");
1487 _cutthrough_flush_send(void)
1489 int n= ctblock.ptr-ctblock.buffer;
1492 if(!cutthrough_send(n))
1498 /* Send out any bufferred output. Return boolean success. */
1500 cutthrough_flush_send(void)
1502 if (_cutthrough_flush_send()) return TRUE;
1503 cancel_cutthrough_connection("transmit failed");
1509 cutthrough_put_nl(void)
1511 return cutthrough_puts(US"\r\n", 2);
1515 /* Get and check response from cutthrough target */
1517 cutthrough_response(char expect, uschar ** copy)
1519 smtp_inblock inblock;
1520 uschar inbuffer[4096];
1521 uschar responsebuffer[4096];
1523 inblock.buffer = inbuffer;
1524 inblock.buffersize = sizeof(inbuffer);
1525 inblock.ptr = inbuffer;
1526 inblock.ptrend = inbuffer;
1527 inblock.sock = cutthrough.fd;
1528 /* this relies on (inblock.sock == tls_out.active) */
1529 if(!smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), expect, CUTTHROUGH_DATA_TIMEOUT))
1530 cancel_cutthrough_connection("target timeout on read");
1535 *copy = cp = string_copy(responsebuffer);
1536 /* Trim the trailing end of line */
1537 cp += Ustrlen(responsebuffer);
1538 if(cp > *copy && cp[-1] == '\n') *--cp = '\0';
1539 if(cp > *copy && cp[-1] == '\r') *--cp = '\0';
1542 return responsebuffer[0];
1546 /* Negotiate dataphase with the cutthrough target, returning success boolean */
1548 cutthrough_predata(void)
1550 if(cutthrough.fd < 0)
1553 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> DATA\n");
1554 cutthrough_puts(US"DATA\r\n", 6);
1555 cutthrough_flush_send();
1557 /* Assume nothing buffered. If it was it gets ignored. */
1558 return cutthrough_response('3', NULL) == '3';
1562 /* fd and tctx args only to match write_chunk() */
1564 cutthrough_write_chunk(int fd, transport_ctx * tctx, uschar * s, int len)
1567 while(s && (s2 = Ustrchr(s, '\n')))
1569 if(!cutthrough_puts(s, s2-s) || !cutthrough_put_nl())
1577 /* Buffered send of headers. Return success boolean. */
1578 /* Expands newlines to wire format (CR,NL). */
1579 /* Also sends header-terminating blank line. */
1581 cutthrough_headers_send(void)
1585 if(cutthrough.fd < 0)
1588 /* We share a routine with the mainline transport to handle header add/remove/rewrites,
1589 but having a separate buffered-output function (for now)
1591 HDEBUG(D_acl) debug_printf("----------- start cutthrough headers send -----------\n");
1593 tctx.tblock = cutthrough.addr.transport;
1594 tctx.addr = &cutthrough.addr;
1595 tctx.check_string = US".";
1596 tctx.escape_string = US"..";
1597 tctx.options = topt_use_crlf;
1599 if (!transport_headers_send(cutthrough.fd, &tctx, &cutthrough_write_chunk))
1602 HDEBUG(D_acl) debug_printf("----------- done cutthrough headers send ------------\n");
1608 close_cutthrough_connection(const char * why)
1610 if(cutthrough.fd >= 0)
1612 /* We could be sending this after a bunch of data, but that is ok as
1613 the only way to cancel the transfer in dataphase is to drop the tcp
1614 conn before the final dot.
1616 ctblock.ptr = ctbuffer;
1617 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> QUIT\n");
1618 _cutthrough_puts(US"QUIT\r\n", 6); /* avoid recursion */
1619 _cutthrough_flush_send();
1620 /* No wait for response */
1623 tls_close(FALSE, TRUE);
1625 (void)close(cutthrough.fd);
1627 HDEBUG(D_acl) debug_printf("----------- cutthrough shutdown (%s) ------------\n", why);
1629 ctblock.ptr = ctbuffer;
1633 cancel_cutthrough_connection(const char * why)
1635 close_cutthrough_connection(why);
1636 cutthrough.delivery = FALSE;
1642 /* Have senders final-dot. Send one to cutthrough target, and grab the response.
1643 Log an OK response as a transmission.
1644 Close the connection.
1645 Return smtp response-class digit.
1648 cutthrough_finaldot(void)
1651 address_item * addr;
1652 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> .\n");
1654 /* Assume data finshed with new-line */
1655 if( !cutthrough_puts(US".", 1)
1656 || !cutthrough_put_nl()
1657 || !cutthrough_flush_send()
1659 return cutthrough.addr.message;
1661 res = cutthrough_response('2', &cutthrough.addr.message);
1662 for (addr = &cutthrough.addr; addr; addr = addr->next)
1664 addr->message = cutthrough.addr.message;
1668 delivery_log(LOG_MAIN, addr, (int)'>', NULL);
1669 close_cutthrough_connection("delivered");
1673 delivery_log(LOG_MAIN, addr, 0,
1674 US"tmp-reject from cutthrough after DATA:");
1678 delivery_log(LOG_MAIN|LOG_REJECT, addr, 0,
1679 US"rejected after DATA:");
1686 return cutthrough.addr.message;
1691 /*************************************************
1692 * Copy error to toplevel address *
1693 *************************************************/
1695 /* This function is used when a verify fails or defers, to ensure that the
1696 failure or defer information is in the original toplevel address. This applies
1697 when an address is redirected to a single new address, and the failure or
1698 deferral happens to the child address.
1701 vaddr the verify address item
1702 addr the final address item
1705 Returns: the value of YIELD
1709 copy_error(address_item *vaddr, address_item *addr, int yield)
1713 vaddr->message = addr->message;
1714 vaddr->user_message = addr->user_message;
1715 vaddr->basic_errno = addr->basic_errno;
1716 vaddr->more_errno = addr->more_errno;
1717 vaddr->prop.address_data = addr->prop.address_data;
1718 copyflag(vaddr, addr, af_pass_message);
1726 /**************************************************
1727 * printf that automatically handles TLS if needed *
1728 ***************************************************/
1730 /* This function is used by verify_address() as a substitute for all fprintf()
1731 calls; a direct fprintf() will not produce output in a TLS SMTP session, such
1732 as a response to an EXPN command. smtp_in.c makes smtp_printf available but
1733 that assumes that we always use the smtp_out FILE* when not using TLS or the
1734 ssl buffer when we are. Instead we take a FILE* parameter and check to see if
1735 that is smtp_out; if so, smtp_printf() with TLS support, otherwise regular
1739 f the candidate FILE* to write to
1740 format format string
1741 ... optional arguments
1747 static void PRINTF_FUNCTION(2,3)
1748 respond_printf(FILE *f, const char *format, ...)
1752 va_start(ap, format);
1753 if (smtp_out && (f == smtp_out))
1754 smtp_vprintf(format, ap);
1756 vfprintf(f, format, ap);
1762 /*************************************************
1763 * Verify an email address *
1764 *************************************************/
1766 /* This function is used both for verification (-bv and at other times) and
1767 address testing (-bt), which is indicated by address_test_mode being set.
1770 vaddr contains the address to verify; the next field in this block
1772 f if not NULL, write the result to this file
1773 options various option bits:
1774 vopt_fake_sender => this sender verify is not for the real
1775 sender (it was verify=sender=xxxx or an address from a
1776 header line) - rewriting must not change sender_address
1777 vopt_is_recipient => this is a recipient address, otherwise
1778 it's a sender address - this affects qualification and
1779 rewriting and messages from callouts
1780 vopt_qualify => qualify an unqualified address; else error
1781 vopt_expn => called from SMTP EXPN command
1782 vopt_success_on_redirect => when a new address is generated
1783 the verification instantly succeeds
1785 These ones are used by do_callout() -- the options variable
1788 vopt_callout_fullpm => if postmaster check, do full one
1789 vopt_callout_no_cache => don't use callout cache
1790 vopt_callout_random => do the "random" thing
1791 vopt_callout_recipsender => use real sender for recipient
1792 vopt_callout_recippmaster => use postmaster for recipient
1794 callout if > 0, specifies that callout is required, and gives timeout
1795 for individual commands
1796 callout_overall if > 0, gives overall timeout for the callout function;
1797 if < 0, a default is used (see do_callout())
1798 callout_connect the connection timeout for callouts
1799 se_mailfrom when callout is requested to verify a sender, use this
1800 in MAIL FROM; NULL => ""
1801 pm_mailfrom when callout is requested, if non-NULL, do the postmaster
1802 thing and use this as the sender address (may be "")
1804 routed if not NULL, set TRUE if routing succeeded, so we can
1805 distinguish between routing failed and callout failed
1807 Returns: OK address verified
1808 FAIL address failed to verify
1809 DEFER can't tell at present
1813 verify_address(address_item *vaddr, FILE *f, int options, int callout,
1814 int callout_overall, int callout_connect, uschar *se_mailfrom,
1815 uschar *pm_mailfrom, BOOL *routed)
1818 BOOL full_info = (f == NULL)? FALSE : (debug_selector != 0);
1819 BOOL expn = (options & vopt_expn) != 0;
1820 BOOL success_on_redirect = (options & vopt_success_on_redirect) != 0;
1823 int verify_type = expn? v_expn :
1824 address_test_mode? v_none :
1825 options & vopt_is_recipient? v_recipient : v_sender;
1826 address_item *addr_list;
1827 address_item *addr_new = NULL;
1828 address_item *addr_remote = NULL;
1829 address_item *addr_local = NULL;
1830 address_item *addr_succeed = NULL;
1831 uschar **failure_ptr = options & vopt_is_recipient
1832 ? &recipient_verify_failure : &sender_verify_failure;
1833 uschar *ko_prefix, *cr;
1834 uschar *address = vaddr->address;
1835 uschar *save_sender;
1836 uschar null_sender[] = { 0 }; /* Ensure writeable memory */
1838 /* Clear, just in case */
1840 *failure_ptr = NULL;
1842 /* Set up a prefix and suffix for error message which allow us to use the same
1843 output statements both in EXPN mode (where an SMTP response is needed) and when
1844 debugging with an output file. */
1848 ko_prefix = US"553 ";
1851 else ko_prefix = cr = US"";
1853 /* Add qualify domain if permitted; otherwise an unqualified address fails. */
1855 if (parse_find_at(address) == NULL)
1857 if ((options & vopt_qualify) == 0)
1860 respond_printf(f, "%sA domain is required for \"%s\"%s\n",
1861 ko_prefix, address, cr);
1862 *failure_ptr = US"qualify";
1865 address = rewrite_address_qualify(address, options & vopt_is_recipient);
1870 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1871 debug_printf("%s %s\n", address_test_mode? "Testing" : "Verifying", address);
1874 /* Rewrite and report on it. Clear the domain and local part caches - these
1875 may have been set by domains and local part tests during an ACL. */
1877 if (global_rewrite_rules != NULL)
1879 uschar *old = address;
1880 address = rewrite_address(address, options & vopt_is_recipient, FALSE,
1881 global_rewrite_rules, rewrite_existflags);
1884 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->localpart_cache[i] = 0;
1885 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->domain_cache[i] = 0;
1886 if (f != NULL && !expn) fprintf(f, "Address rewritten as: %s\n", address);
1890 /* If this is the real sender address, we must update sender_address at
1891 this point, because it may be referred to in the routers. */
1893 if ((options & (vopt_fake_sender|vopt_is_recipient)) == 0)
1894 sender_address = address;
1896 /* If the address was rewritten to <> no verification can be done, and we have
1897 to return OK. This rewriting is permitted only for sender addresses; for other
1898 addresses, such rewriting fails. */
1900 if (address[0] == 0) return OK;
1902 /* Flip the legacy TLS-related variables over to the outbound set in case
1903 they're used in the context of a transport used by verification. Reset them
1904 at exit from this routine (so no returns allowed from here on). */
1906 tls_modify_variables(&tls_out);
1908 /* Save a copy of the sender address for re-instating if we change it to <>
1909 while verifying a sender address (a nice bit of self-reference there). */
1911 save_sender = sender_address;
1913 /* Observability variable for router/transport use */
1915 verify_mode = options & vopt_is_recipient ? US"R" : US"S";
1917 /* Update the address structure with the possibly qualified and rewritten
1918 address. Set it up as the starting address on the chain of new addresses. */
1920 vaddr->address = address;
1923 /* We need a loop, because an address can generate new addresses. We must also
1924 cope with generated pipes and files at the top level. (See also the code and
1925 comment in deliver.c.) However, it is usually the case that the router for
1926 user's .forward files has its verify flag turned off.
1928 If an address generates more than one child, the loop is used only when
1929 full_info is set, and this can only be set locally. Remote enquiries just get
1930 information about the top level address, not anything that it generated. */
1935 address_item *addr = addr_new;
1937 addr_new = addr->next;
1942 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1943 debug_printf("Considering %s\n", addr->address);
1946 /* Handle generated pipe, file or reply addresses. We don't get these
1947 when handling EXPN, as it does only one level of expansion. */
1949 if (testflag(addr, af_pfr))
1956 if (addr->address[0] == '>')
1958 allow = testflag(addr, af_allow_reply);
1959 fprintf(f, "%s -> mail %s", addr->parent->address, addr->address + 1);
1963 allow = (addr->address[0] == '|')?
1964 testflag(addr, af_allow_pipe) : testflag(addr, af_allow_file);
1965 fprintf(f, "%s -> %s", addr->parent->address, addr->address);
1968 if (addr->basic_errno == ERRNO_BADTRANSPORT)
1969 fprintf(f, "\n*** Error in setting up pipe, file, or autoreply:\n"
1970 "%s\n", addr->message);
1972 fprintf(f, "\n transport = %s\n", addr->transport->name);
1974 fprintf(f, " *** forbidden ***\n");
1979 /* Just in case some router parameter refers to it. */
1981 return_path = addr->prop.errors_address
1982 ? addr->prop.errors_address : sender_address;
1984 /* Split the address into domain and local part, handling the %-hack if
1985 necessary, and then route it. While routing a sender address, set
1986 $sender_address to <> because that is what it will be if we were trying to
1987 send a bounce to the sender. */
1989 if (routed) *routed = FALSE;
1990 if ((rc = deliver_split_address(addr)) == OK)
1992 if (!(options & vopt_is_recipient)) sender_address = null_sender;
1993 rc = route_address(addr, &addr_local, &addr_remote, &addr_new,
1994 &addr_succeed, verify_type);
1995 sender_address = save_sender; /* Put back the real sender */
1998 /* If routing an address succeeded, set the flag that remembers, for use when
1999 an ACL cached a sender verify (in case a callout fails). Then if routing set
2000 up a list of hosts or the transport has a host list, and the callout option
2001 is set, and we aren't in a host checking run, do the callout verification,
2002 and set another flag that notes that a callout happened. */
2006 if (routed) *routed = TRUE;
2009 transport_instance * tp;
2010 host_item * host_list = addr->host_list;
2012 /* Make up some data for use in the case where there is no remote
2015 transport_feedback tf = {
2016 NULL, /* interface (=> any) */
2017 US"smtp", /* port */
2018 US"smtp", /* protocol */
2020 US"$smtp_active_hostname", /* helo_data */
2021 FALSE, /* hosts_override */
2022 FALSE, /* hosts_randomize */
2023 FALSE, /* gethostbyname */
2024 TRUE, /* qualify_single */
2025 FALSE /* search_parents */
2028 /* If verification yielded a remote transport, we want to use that
2029 transport's options, so as to mimic what would happen if we were really
2030 sending a message to this address. */
2032 if ((tp = addr->transport) && !tp->info->local)
2034 (void)(tp->setup)(tp, addr, &tf, 0, 0, NULL);
2036 /* If the transport has hosts and the router does not, or if the
2037 transport is configured to override the router's hosts, we must build a
2038 host list of the transport's hosts, and find the IP addresses */
2040 if (tf.hosts && (!host_list || tf.hosts_override))
2043 const uschar *save_deliver_domain = deliver_domain;
2044 uschar *save_deliver_localpart = deliver_localpart;
2046 host_list = NULL; /* Ignore the router's hosts */
2048 deliver_domain = addr->domain;
2049 deliver_localpart = addr->local_part;
2050 s = expand_string(tf.hosts);
2051 deliver_domain = save_deliver_domain;
2052 deliver_localpart = save_deliver_localpart;
2056 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand list of hosts "
2057 "\"%s\" in %s transport for callout: %s", tf.hosts,
2058 tp->name, expand_string_message);
2063 host_item *host, *nexthost;
2064 host_build_hostlist(&host_list, s, tf.hosts_randomize);
2066 /* Just ignore failures to find a host address. If we don't manage
2067 to find any addresses, the callout will defer. Note that more than
2068 one address may be found for a single host, which will result in
2069 additional host items being inserted into the chain. Hence we must
2070 save the next host first. */
2072 flags = HOST_FIND_BY_A;
2073 if (tf.qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
2074 if (tf.search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
2076 for (host = host_list; host; host = nexthost)
2078 nexthost = host->next;
2079 if (tf.gethostbyname ||
2080 string_is_ip_address(host->name, NULL) != 0)
2081 (void)host_find_byname(host, NULL, flags, NULL, TRUE);
2084 dnssec_domains * dnssec_domains = NULL;
2085 if (Ustrcmp(tp->driver_name, "smtp") == 0)
2087 smtp_transport_options_block * ob =
2088 (smtp_transport_options_block *) tp->options_block;
2089 dnssec_domains = &ob->dnssec;
2092 (void)host_find_bydns(host, NULL, flags, NULL, NULL, NULL,
2093 dnssec_domains, NULL, NULL);
2100 /* Can only do a callout if we have at least one host! If the callout
2101 fails, it will have set ${sender,recipient}_verify_failure. */
2105 HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n");
2106 if (host_checking && !host_checking_callout)
2109 debug_printf("... callout omitted by default when host testing\n"
2110 "(Use -bhc if you want the callouts to happen.)\n");
2115 deliver_set_expansions(addr);
2117 rc = do_callout(addr, host_list, &tf, callout, callout_overall,
2118 callout_connect, options, se_mailfrom, pm_mailfrom);
2123 HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor "
2124 "transport provided a host list\n");
2129 /* Otherwise, any failure is a routing failure */
2131 else *failure_ptr = US"route";
2133 /* A router may return REROUTED if it has set up a child address as a result
2134 of a change of domain name (typically from widening). In this case we always
2135 want to continue to verify the new child. */
2137 if (rc == REROUTED) continue;
2139 /* Handle hard failures */
2146 address_item *p = addr->parent;
2148 respond_printf(f, "%s%s %s", ko_prefix,
2149 full_info ? addr->address : address,
2150 address_test_mode ? "is undeliverable" : "failed to verify");
2151 if (!expn && admin_user)
2153 if (addr->basic_errno > 0)
2154 respond_printf(f, ": %s", strerror(addr->basic_errno));
2156 respond_printf(f, ": %s", addr->message);
2159 /* Show parents iff doing full info */
2161 if (full_info) while (p)
2163 respond_printf(f, "%s\n <-- %s", cr, p->address);
2166 respond_printf(f, "%s\n", cr);
2168 cancel_cutthrough_connection("routing hard fail");
2172 yield = copy_error(vaddr, addr, FAIL);
2180 else if (rc == DEFER)
2185 address_item *p = addr->parent;
2186 respond_printf(f, "%s%s cannot be resolved at this time", ko_prefix,
2187 full_info? addr->address : address);
2188 if (!expn && admin_user)
2190 if (addr->basic_errno > 0)
2191 respond_printf(f, ": %s", strerror(addr->basic_errno));
2193 respond_printf(f, ": %s", addr->message);
2194 else if (addr->basic_errno <= 0)
2195 respond_printf(f, ": unknown error");
2198 /* Show parents iff doing full info */
2200 if (full_info) while (p)
2202 respond_printf(f, "%s\n <-- %s", cr, p->address);
2205 respond_printf(f, "%s\n", cr);
2207 cancel_cutthrough_connection("routing soft fail");
2211 yield = copy_error(vaddr, addr, DEFER);
2214 if (yield == OK) yield = DEFER;
2217 /* If we are handling EXPN, we do not want to continue to route beyond
2218 the top level (whose address is in "address"). */
2222 uschar *ok_prefix = US"250-";
2225 if (!addr_local && !addr_remote)
2226 respond_printf(f, "250 mail to <%s> is discarded\r\n", address);
2228 respond_printf(f, "250 <%s>\r\n", address);
2232 address_item *addr2 = addr_new;
2233 addr_new = addr2->next;
2234 if (!addr_new) ok_prefix = US"250 ";
2235 respond_printf(f, "%s<%s>\r\n", ok_prefix, addr2->address);
2241 /* Successful routing other than EXPN. */
2245 /* Handle successful routing when short info wanted. Otherwise continue for
2246 other (generated) addresses. Short info is the operational case. Full info
2247 can be requested only when debug_selector != 0 and a file is supplied.
2249 There is a conflict between the use of aliasing as an alternate email
2250 address, and as a sort of mailing list. If an alias turns the incoming
2251 address into just one address (e.g. J.Caesar->jc44) you may well want to
2252 carry on verifying the generated address to ensure it is valid when
2253 checking incoming mail. If aliasing generates multiple addresses, you
2254 probably don't want to do this. Exim therefore treats the generation of
2255 just a single new address as a special case, and continues on to verify the
2256 generated address. */
2258 if ( !full_info /* Stop if short info wanted AND */
2259 && ( ( !addr_new /* No new address OR */
2260 || addr_new->next /* More than one new address OR */
2261 || testflag(addr_new, af_pfr) /* New address is pfr */
2264 ( addr_new /* At least one new address AND */
2265 && success_on_redirect /* success_on_redirect is set */
2269 if (f) fprintf(f, "%s %s\n",
2270 address, address_test_mode ? "is deliverable" : "verified");
2272 /* If we have carried on to verify a child address, we want the value
2273 of $address_data to be that of the child */
2275 vaddr->prop.address_data = addr->prop.address_data;
2277 /* If stopped because more than one new address, cannot cutthrough */
2279 if (addr_new && addr_new->next)
2280 cancel_cutthrough_connection("multiple addresses from routing");
2286 } /* Loop for generated addresses */
2288 /* Display the full results of the successful routing, including any generated
2289 addresses. Control gets here only when full_info is set, which requires f not
2290 to be NULL, and this occurs only when a top-level verify is called with the
2291 debugging switch on.
2293 If there are no local and no remote addresses, and there were no pipes, files,
2294 or autoreplies, and there were no errors or deferments, the message is to be
2295 discarded, usually because of the use of :blackhole: in an alias file. */
2297 if (allok && !addr_local && !addr_remote)
2299 fprintf(f, "mail to %s is discarded\n", address);
2303 for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++)
2306 address_item *addr = addr_list;
2307 address_item *p = addr->parent;
2308 transport_instance * tp = addr->transport;
2310 addr_list = addr->next;
2312 fprintf(f, "%s", CS addr->address);
2313 #ifdef EXPERIMENTAL_SRS
2314 if(addr->prop.srs_sender)
2315 fprintf(f, " [srs = %s]", addr->prop.srs_sender);
2318 /* If the address is a duplicate, show something about it. */
2320 if (!testflag(addr, af_pfr))
2323 if ((tnode = tree_search(tree_duplicates, addr->unique)))
2324 fprintf(f, " [duplicate, would not be delivered]");
2325 else tree_add_duplicate(addr->unique, addr);
2328 /* Now show its parents */
2330 for (p = addr->parent; p; p = p->parent)
2331 fprintf(f, "\n <-- %s", p->address);
2334 /* Show router, and transport */
2336 fprintf(f, "router = %s, transport = %s\n",
2337 addr->router->name, tp ? tp->name : US"unset");
2339 /* Show any hosts that are set up by a router unless the transport
2340 is going to override them; fiddle a bit to get a nice format. */
2342 if (addr->host_list && tp && !tp->overrides_hosts)
2347 for (h = addr->host_list; h; h = h->next)
2348 { /* get max lengths of host names, addrs */
2349 int len = Ustrlen(h->name);
2350 if (len > maxlen) maxlen = len;
2351 len = h->address ? Ustrlen(h->address) : 7;
2352 if (len > maxaddlen) maxaddlen = len;
2354 for (h = addr->host_list; h; h = h->next)
2356 fprintf(f, " host %-*s ", maxlen, h->name);
2359 fprintf(f, "[%s%-*c", h->address, maxaddlen+1 - Ustrlen(h->address), ']');
2360 else if (tp->info->local)
2361 fprintf(f, " %-*s ", maxaddlen, ""); /* Omit [unknown] for local */
2363 fprintf(f, "[%s%-*c", "unknown", maxaddlen+1 - 7, ']');
2365 if (h->mx >= 0) fprintf(f, " MX=%d", h->mx);
2366 if (h->port != PORT_NONE) fprintf(f, " port=%d", h->port);
2367 if (running_in_test_harness && h->dnssec == DS_YES) fputs(" AD", f);
2368 if (h->status == hstatus_unusable) fputs(" ** unusable **", f);
2374 /* Yield will be DEFER or FAIL if any one address has, only for full_info (which is
2375 the -bv or -bt case). */
2379 tls_modify_variables(&tls_in);
2387 /*************************************************
2388 * Check headers for syntax errors *
2389 *************************************************/
2391 /* This function checks those header lines that contain addresses, and verifies
2392 that all the addresses therein are syntactially correct.
2395 msgptr where to put an error message
2402 verify_check_headers(uschar **msgptr)
2408 for (h = header_list; h != NULL && yield == OK; h = h->next)
2410 if (h->type != htype_from &&
2411 h->type != htype_reply_to &&
2412 h->type != htype_sender &&
2413 h->type != htype_to &&
2414 h->type != htype_cc &&
2415 h->type != htype_bcc)
2418 colon = Ustrchr(h->text, ':');
2420 while (isspace(*s)) s++;
2422 /* Loop for multiple addresses in the header, enabling group syntax. Note
2423 that we have to reset this after the header has been scanned. */
2425 parse_allow_group = TRUE;
2429 uschar *ss = parse_find_address_end(s, FALSE);
2430 uschar *recipient, *errmess;
2431 int terminator = *ss;
2432 int start, end, domain;
2434 /* Temporarily terminate the string at this point, and extract the
2435 operative address within, allowing group syntax. */
2438 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2441 /* Permit an unqualified address only if the message is local, or if the
2442 sending host is configured to be permitted to send them. */
2444 if (recipient != NULL && domain == 0)
2446 if (h->type == htype_from || h->type == htype_sender)
2448 if (!allow_unqualified_sender) recipient = NULL;
2452 if (!allow_unqualified_recipient) recipient = NULL;
2454 if (recipient == NULL) errmess = US"unqualified address not permitted";
2457 /* It's an error if no address could be extracted, except for the special
2458 case of an empty address. */
2460 if (recipient == NULL && Ustrcmp(errmess, "empty address") != 0)
2462 uschar *verb = US"is";
2467 /* Arrange not to include any white space at the end in the
2468 error message or the header name. */
2470 while (t > s && isspace(t[-1])) t--;
2471 while (tt > h->text && isspace(tt[-1])) tt--;
2473 /* Add the address that failed to the error message, since in a
2474 header with very many addresses it is sometimes hard to spot
2475 which one is at fault. However, limit the amount of address to
2476 quote - cases have been seen where, for example, a missing double
2477 quote in a humungous To: header creates an "address" that is longer
2478 than string_sprintf can handle. */
2487 /* deconst cast ok as we're passing a non-const to string_printing() */
2488 *msgptr = US string_printing(
2489 string_sprintf("%s: failing address in \"%.*s:\" header %s: %.*s",
2490 errmess, tt - h->text, h->text, verb, len, s));
2493 break; /* Out of address loop */
2496 /* Advance to the next address */
2498 s = ss + (terminator? 1:0);
2499 while (isspace(*s)) s++;
2500 } /* Next address */
2502 parse_allow_group = FALSE;
2503 parse_found_group = FALSE;
2504 } /* Next header unless yield has been set FALSE */
2510 /*************************************************
2511 * Check header names for 8-bit characters *
2512 *************************************************/
2514 /* This function checks for invalid charcters in header names. See
2515 RFC 5322, 2.2. and RFC 6532, 3.
2518 msgptr where to put an error message
2525 verify_check_header_names_ascii(uschar **msgptr)
2530 for (h = header_list; h != NULL; h = h->next)
2532 colon = Ustrchr(h->text, ':');
2533 for(s = h->text; s < colon; s++)
2535 if ((*s < 33) || (*s > 126))
2537 *msgptr = string_sprintf("Invalid character in header \"%.*s\" found",
2538 colon - h->text, h->text);
2546 /*************************************************
2547 * Check for blind recipients *
2548 *************************************************/
2550 /* This function checks that every (envelope) recipient is mentioned in either
2551 the To: or Cc: header lines, thus detecting blind carbon copies.
2553 There are two ways of scanning that could be used: either scan the header lines
2554 and tick off the recipients, or scan the recipients and check the header lines.
2555 The original proposed patch did the former, but I have chosen to do the latter,
2556 because (a) it requires no memory and (b) will use fewer resources when there
2557 are many addresses in To: and/or Cc: and only one or two envelope recipients.
2560 Returns: OK if there are no blind recipients
2561 FAIL if there is at least one blind recipient
2565 verify_check_notblind(void)
2568 for (i = 0; i < recipients_count; i++)
2572 uschar *address = recipients_list[i].address;
2574 for (h = header_list; !found && h != NULL; h = h->next)
2578 if (h->type != htype_to && h->type != htype_cc) continue;
2580 colon = Ustrchr(h->text, ':');
2582 while (isspace(*s)) s++;
2584 /* Loop for multiple addresses in the header, enabling group syntax. Note
2585 that we have to reset this after the header has been scanned. */
2587 parse_allow_group = TRUE;
2591 uschar *ss = parse_find_address_end(s, FALSE);
2592 uschar *recipient,*errmess;
2593 int terminator = *ss;
2594 int start, end, domain;
2596 /* Temporarily terminate the string at this point, and extract the
2597 operative address within, allowing group syntax. */
2600 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2603 /* If we found a valid recipient that has a domain, compare it with the
2604 envelope recipient. Local parts are compared case-sensitively, domains
2605 case-insensitively. By comparing from the start with length "domain", we
2606 include the "@" at the end, which ensures that we are comparing the whole
2607 local part of each address. */
2609 if (recipient != NULL && domain != 0)
2611 found = Ustrncmp(recipient, address, domain) == 0 &&
2612 strcmpic(recipient + domain, address + domain) == 0;
2616 /* Advance to the next address */
2618 s = ss + (terminator? 1:0);
2619 while (isspace(*s)) s++;
2620 } /* Next address */
2622 parse_allow_group = FALSE;
2623 parse_found_group = FALSE;
2624 } /* Next header (if found is false) */
2626 if (!found) return FAIL;
2627 } /* Next recipient */
2634 /*************************************************
2635 * Find if verified sender *
2636 *************************************************/
2638 /* Usually, just a single address is verified as the sender of the message.
2639 However, Exim can be made to verify other addresses as well (often related in
2640 some way), and this is useful in some environments. There may therefore be a
2641 chain of such addresses that have previously been tested. This function finds
2642 whether a given address is on the chain.
2644 Arguments: the address to be verified
2645 Returns: pointer to an address item, or NULL
2649 verify_checked_sender(uschar *sender)
2652 for (addr = sender_verified_list; addr != NULL; addr = addr->next)
2653 if (Ustrcmp(sender, addr->address) == 0) break;
2661 /*************************************************
2662 * Get valid header address *
2663 *************************************************/
2665 /* Scan the originator headers of the message, looking for an address that
2666 verifies successfully. RFC 822 says:
2668 o The "Sender" field mailbox should be sent notices of
2669 any problems in transport or delivery of the original
2670 messages. If there is no "Sender" field, then the
2671 "From" field mailbox should be used.
2673 o If the "Reply-To" field exists, then the reply should
2674 go to the addresses indicated in that field and not to
2675 the address(es) indicated in the "From" field.
2677 So we check a Sender field if there is one, else a Reply_to field, else a From
2678 field. As some strange messages may have more than one of these fields,
2679 especially if they are resent- fields, check all of them if there is more than
2683 user_msgptr points to where to put a user error message
2684 log_msgptr points to where to put a log error message
2685 callout timeout for callout check (passed to verify_address())
2686 callout_overall overall callout timeout (ditto)
2687 callout_connect connect callout timeout (ditto)
2688 se_mailfrom mailfrom for verify; NULL => ""
2689 pm_mailfrom sender for pm callout check (passed to verify_address())
2690 options callout options (passed to verify_address())
2691 verrno where to put the address basic_errno
2693 If log_msgptr is set to something without setting user_msgptr, the caller
2694 normally uses log_msgptr for both things.
2696 Returns: result of the verification attempt: OK, FAIL, or DEFER;
2697 FAIL is given if no appropriate headers are found
2701 verify_check_header_address(uschar **user_msgptr, uschar **log_msgptr,
2702 int callout, int callout_overall, int callout_connect, uschar *se_mailfrom,
2703 uschar *pm_mailfrom, int options, int *verrno)
2705 static int header_types[] = { htype_sender, htype_reply_to, htype_from };
2710 for (i = 0; i < 3 && !done; i++)
2713 for (h = header_list; h != NULL && !done; h = h->next)
2715 int terminator, new_ok;
2716 uschar *s, *ss, *endname;
2718 if (h->type != header_types[i]) continue;
2719 s = endname = Ustrchr(h->text, ':') + 1;
2721 /* Scan the addresses in the header, enabling group syntax. Note that we
2722 have to reset this after the header has been scanned. */
2724 parse_allow_group = TRUE;
2728 address_item *vaddr;
2730 while (isspace(*s) || *s == ',') s++;
2731 if (*s == 0) break; /* End of header */
2733 ss = parse_find_address_end(s, FALSE);
2735 /* The terminator is a comma or end of header, but there may be white
2736 space preceding it (including newline for the last address). Move back
2737 past any white space so we can check against any cached envelope sender
2738 address verifications. */
2740 while (isspace(ss[-1])) ss--;
2744 HDEBUG(D_verify) debug_printf("verifying %.*s header address %s\n",
2745 (int)(endname - h->text), h->text, s);
2747 /* See if we have already verified this address as an envelope sender,
2748 and if so, use the previous answer. */
2750 vaddr = verify_checked_sender(s);
2752 if (vaddr != NULL && /* Previously checked */
2753 (callout <= 0 || /* No callout needed; OR */
2754 vaddr->special_action > 256)) /* Callout was done */
2756 new_ok = vaddr->special_action & 255;
2757 HDEBUG(D_verify) debug_printf("previously checked as envelope sender\n");
2758 *ss = terminator; /* Restore shortened string */
2761 /* Otherwise we run the verification now. We must restore the shortened
2762 string before running the verification, so the headers are correct, in
2763 case there is any rewriting. */
2767 int start, end, domain;
2768 uschar *address = parse_extract_address(s, log_msgptr, &start, &end,
2773 /* If we found an empty address, just carry on with the next one, but
2774 kill the message. */
2776 if (address == NULL && Ustrcmp(*log_msgptr, "empty address") == 0)
2783 /* If verification failed because of a syntax error, fail this
2784 function, and ensure that the failing address gets added to the error
2787 if (address == NULL)
2790 while (ss > s && isspace(ss[-1])) ss--;
2791 *log_msgptr = string_sprintf("syntax error in '%.*s' header when "
2792 "scanning for sender: %s in \"%.*s\"",
2793 endname - h->text, h->text, *log_msgptr, ss - s, s);
2799 /* Else go ahead with the sender verification. But it isn't *the*
2800 sender of the message, so set vopt_fake_sender to stop sender_address
2801 being replaced after rewriting or qualification. */
2805 vaddr = deliver_make_addr(address, FALSE);
2806 new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender,
2807 callout, callout_overall, callout_connect, se_mailfrom,
2812 /* We now have the result, either newly found, or cached. If we are
2813 giving out error details, set a specific user error. This means that the
2814 last of these will be returned to the user if all three fail. We do not
2815 set a log message - the generic one below will be used. */
2819 *verrno = vaddr->basic_errno;
2820 if (smtp_return_error_details)
2822 *user_msgptr = string_sprintf("Rejected after DATA: "
2823 "could not verify \"%.*s\" header address\n%s: %s",
2824 endname - h->text, h->text, vaddr->address, vaddr->message);
2828 /* Success or defer */
2837 if (new_ok == DEFER) yield = DEFER;
2839 /* Move on to any more addresses in the header */
2842 } /* Next address */
2844 parse_allow_group = FALSE;
2845 parse_found_group = FALSE;
2846 } /* Next header, unless done */
2847 } /* Next header type unless done */
2849 if (yield == FAIL && *log_msgptr == NULL)
2850 *log_msgptr = US"there is no valid sender in any header line";
2852 if (yield == DEFER && *log_msgptr == NULL)
2853 *log_msgptr = US"all attempts to verify a sender in a header line deferred";
2861 /*************************************************
2862 * Get RFC 1413 identification *
2863 *************************************************/
2865 /* Attempt to get an id from the sending machine via the RFC 1413 protocol. If
2866 the timeout is set to zero, then the query is not done. There may also be lists
2867 of hosts and nets which are exempt. To guard against malefactors sending
2868 non-printing characters which could, for example, disrupt a message's headers,
2869 make sure the string consists of printing characters only.
2872 port the port to connect to; usually this is IDENT_PORT (113), but when
2873 running in the test harness with -bh a different value is used.
2877 Side effect: any received ident value is put in sender_ident (NULL otherwise)
2881 verify_get_ident(int port)
2883 int sock, host_af, qlen;
2884 int received_sender_port, received_interface_port, n;
2886 uschar buffer[2048];
2888 /* Default is no ident. Check whether we want to do an ident check for this
2891 sender_ident = NULL;
2892 if (rfc1413_query_timeout <= 0 || verify_check_host(&rfc1413_hosts) != OK)
2895 DEBUG(D_ident) debug_printf("doing ident callback\n");
2897 /* Set up a connection to the ident port of the remote host. Bind the local end
2898 to the incoming interface address. If the sender host address is an IPv6
2899 address, the incoming interface address will also be IPv6. */
2901 host_af = (Ustrchr(sender_host_address, ':') == NULL)? AF_INET : AF_INET6;
2902 sock = ip_socket(SOCK_STREAM, host_af);
2903 if (sock < 0) return;
2905 if (ip_bind(sock, host_af, interface_address, 0) < 0)
2907 DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n",
2912 if (ip_connect(sock, host_af, sender_host_address, port, rfc1413_query_timeout)
2915 if (errno == ETIMEDOUT && LOGGING(ident_timeout))
2917 log_write(0, LOG_MAIN, "ident connection to %s timed out",
2918 sender_host_address);
2922 DEBUG(D_ident) debug_printf("ident connection to %s failed: %s\n",
2923 sender_host_address, strerror(errno));
2928 /* Construct and send the query. */
2930 sprintf(CS buffer, "%d , %d\r\n", sender_host_port, interface_port);
2931 qlen = Ustrlen(buffer);
2932 if (send(sock, buffer, qlen, 0) < 0)
2934 DEBUG(D_ident) debug_printf("ident send failed: %s\n", strerror(errno));
2938 /* Read a response line. We put it into the rest of the buffer, using several
2939 recv() calls if necessary. */
2947 int size = sizeof(buffer) - (p - buffer);
2949 if (size <= 0) goto END_OFF; /* Buffer filled without seeing \n. */
2950 count = ip_recv(sock, p, size, rfc1413_query_timeout);
2951 if (count <= 0) goto END_OFF; /* Read error or EOF */
2953 /* Scan what we just read, to see if we have reached the terminating \r\n. Be
2954 generous, and accept a plain \n terminator as well. The only illegal
2957 for (pp = p; pp < p + count; pp++)
2959 if (*pp == 0) goto END_OFF; /* Zero octet not allowed */
2962 if (pp[-1] == '\r') pp--;
2964 goto GOT_DATA; /* Break out of both loops */
2968 /* Reached the end of the data without finding \n. Let the loop continue to
2969 read some more, if there is room. */
2976 /* We have received a line of data. Check it carefully. It must start with the
2977 same two port numbers that we sent, followed by data as defined by the RFC. For
2980 12345 , 25 : USERID : UNIX :root
2982 However, the amount of white space may be different to what we sent. In the
2983 "osname" field there may be several sub-fields, comma separated. The data we
2984 actually want to save follows the third colon. Some systems put leading spaces
2985 in it - we discard those. */
2987 if (sscanf(CS buffer + qlen, "%d , %d%n", &received_sender_port,
2988 &received_interface_port, &n) != 2 ||
2989 received_sender_port != sender_host_port ||
2990 received_interface_port != interface_port)
2993 p = buffer + qlen + n;
2994 while(isspace(*p)) p++;
2995 if (*p++ != ':') goto END_OFF;
2996 while(isspace(*p)) p++;
2997 if (Ustrncmp(p, "USERID", 6) != 0) goto END_OFF;
2999 while(isspace(*p)) p++;
3000 if (*p++ != ':') goto END_OFF;
3001 while (*p != 0 && *p != ':') p++;
3002 if (*p++ == 0) goto END_OFF;
3003 while(isspace(*p)) p++;
3004 if (*p == 0) goto END_OFF;
3006 /* The rest of the line is the data we want. We turn it into printing
3007 characters when we save it, so that it cannot mess up the format of any logging
3008 or Received: lines into which it gets inserted. We keep a maximum of 127
3009 characters. The deconst cast is ok as we fed a nonconst to string_printing() */
3011 sender_ident = US string_printing(string_copyn(p, 127));
3012 DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident);
3022 /*************************************************
3023 * Match host to a single host-list item *
3024 *************************************************/
3026 /* This function compares a host (name or address) against a single item
3027 from a host list. The host name gets looked up if it is needed and is not
3028 already known. The function is called from verify_check_this_host() via
3029 match_check_list(), which is why most of its arguments are in a single block.
3032 arg the argument block (see below)
3033 ss the host-list item
3034 valueptr where to pass back looked up data, or NULL
3035 error for error message when returning ERROR
3038 host_name (a) the host name, or
3039 (b) NULL, implying use sender_host_name and
3040 sender_host_aliases, looking them up if required, or
3041 (c) the empty string, meaning that only IP address matches
3043 host_address the host address
3044 host_ipv4 the IPv4 address taken from an IPv6 one
3048 DEFER lookup deferred
3049 ERROR (a) failed to find the host name or IP address, or
3050 (b) unknown lookup type specified, or
3051 (c) host name encountered when only IP addresses are
3056 check_host(void *arg, const uschar *ss, const uschar **valueptr, uschar **error)
3058 check_host_block *cb = (check_host_block *)arg;
3061 BOOL iplookup = FALSE;
3062 BOOL isquery = FALSE;
3063 BOOL isiponly = cb->host_name != NULL && cb->host_name[0] == 0;
3068 /* Optimize for the special case when the pattern is "*". */
3070 if (*ss == '*' && ss[1] == 0) return OK;
3072 /* If the pattern is empty, it matches only in the case when there is no host -
3073 this can occur in ACL checking for SMTP input using the -bs option. In this
3074 situation, the host address is the empty string. */
3076 if (cb->host_address[0] == 0) return (*ss == 0)? OK : FAIL;
3077 if (*ss == 0) return FAIL;
3079 /* If the pattern is precisely "@" then match against the primary host name,
3080 provided that host name matching is permitted; if it's "@[]" match against the
3081 local host's IP addresses. */
3087 if (isiponly) return ERROR;
3088 ss = primary_hostname;
3090 else if (Ustrcmp(ss, "@[]") == 0)
3092 ip_address_item *ip;
3093 for (ip = host_find_interfaces(); ip != NULL; ip = ip->next)
3094 if (Ustrcmp(ip->address, cb->host_address) == 0) return OK;
3099 /* If the pattern is an IP address, optionally followed by a bitmask count, do
3100 a (possibly masked) comparision with the current IP address. */
3102 if (string_is_ip_address(ss, &maskoffset) != 0)
3103 return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL);
3105 /* The pattern is not an IP address. A common error that people make is to omit
3106 one component of an IPv4 address, either by accident, or believing that, for
3107 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,
3108 which it isn't. (Those applications that do accept 1.2.3 as an IP address
3109 interpret it as 1.2.0.3 because the final component becomes 16-bit - this is an
3110 ancient specification.) To aid in debugging these cases, we give a specific
3111 error if the pattern contains only digits and dots or contains a slash preceded
3112 only by digits and dots (a slash at the start indicates a file name and of
3113 course slashes may be present in lookups, but not preceded only by digits and
3116 for (t = ss; isdigit(*t) || *t == '.'; t++);
3117 if (*t == 0 || (*t == '/' && t != ss))
3119 *error = US"malformed IPv4 address or address mask";
3123 /* See if there is a semicolon in the pattern */
3125 semicolon = Ustrchr(ss, ';');
3127 /* If we are doing an IP address only match, then all lookups must be IP
3128 address lookups, even if there is no "net-". */
3132 iplookup = semicolon != NULL;
3135 /* Otherwise, if the item is of the form net[n]-lookup;<file|query> then it is
3136 a lookup on a masked IP network, in textual form. We obey this code even if we
3137 have already set iplookup, so as to skip over the "net-" prefix and to set the
3138 mask length. The net- stuff really only applies to single-key lookups where the
3139 key is implicit. For query-style lookups the key is specified in the query.
3140 From release 4.30, the use of net- for query style is no longer needed, but we
3141 retain it for backward compatibility. */
3143 if (Ustrncmp(ss, "net", 3) == 0 && semicolon != NULL)
3146 for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0';
3147 if (mlen == 0 && t == ss+3) mlen = -1; /* No mask supplied */
3148 iplookup = (*t++ == '-');
3152 /* Do the IP address lookup if that is indeed what we have */
3160 uschar *filename, *key, *result;
3163 /* Find the search type */
3165 search_type = search_findtype(t, semicolon - t);
3167 if (search_type < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
3168 search_error_message);
3170 /* Adjust parameters for the type of lookup. For a query-style lookup, there
3171 is no file name, and the "key" is just the query. For query-style with a file
3172 name, we have to fish the file off the start of the query. For a single-key
3173 lookup, the key is the current IP address, masked appropriately, and
3174 reconverted to text form, with the mask appended. For IPv6 addresses, specify
3175 dot separators instead of colons, except when the lookup type is "iplsearch".
3178 if (mac_islookup(search_type, lookup_absfilequery))
3180 filename = semicolon + 1;
3182 while (*key != 0 && !isspace(*key)) key++;
3183 filename = string_copyn(filename, key - filename);
3184 while (isspace(*key)) key++;
3186 else if (mac_islookup(search_type, lookup_querystyle))
3189 key = semicolon + 1;
3191 else /* Single-key style */
3193 int sep = (Ustrcmp(lookup_list[search_type]->name, "iplsearch") == 0)?
3195 insize = host_aton(cb->host_address, incoming);
3196 host_mask(insize, incoming, mlen);
3197 (void)host_nmtoa(insize, incoming, mlen, buffer, sep);
3199 filename = semicolon + 1;
3202 /* Now do the actual lookup; note that there is no search_close() because
3203 of the caching arrangements. */
3205 if (!(handle = search_open(filename, search_type, 0, NULL, NULL)))
3206 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s", search_error_message);
3208 result = search_find(handle, filename, key, -1, NULL, 0, 0, NULL);
3209 if (valueptr != NULL) *valueptr = result;
3210 return (result != NULL)? OK : search_find_defer? DEFER: FAIL;
3213 /* The pattern is not an IP address or network reference of any kind. That is,
3214 it is a host name pattern. If this is an IP only match, there's an error in the
3219 *error = US"cannot match host name in match_ip list";
3223 /* Check the characters of the pattern to see if they comprise only letters,
3224 digits, full stops, and hyphens (the constituents of domain names). Allow
3225 underscores, as they are all too commonly found. Sigh. Also, if
3226 allow_utf8_domains is set, allow top-bit characters. */
3228 for (t = ss; *t != 0; t++)
3229 if (!isalnum(*t) && *t != '.' && *t != '-' && *t != '_' &&
3230 (!allow_utf8_domains || *t < 128)) break;
3232 /* If the pattern is a complete domain name, with no fancy characters, look up
3233 its IP address and match against that. Note that a multi-homed host will add
3234 items to the chain. */
3245 /* Using byname rather than bydns here means we cannot determine dnssec
3246 status. On the other hand it is unclear how that could be either
3247 propagated up or enforced. */
3249 rc = host_find_byname(&h, NULL, HOST_FIND_QUALIFY_SINGLE, NULL, FALSE);
3250 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3253 for (hh = &h; hh != NULL; hh = hh->next)
3255 if (host_is_in_net(hh->address, cb->host_address, 0)) return OK;
3259 if (rc == HOST_FIND_AGAIN) return DEFER;
3260 *error = string_sprintf("failed to find IP address for %s", ss);
3264 /* Almost all subsequent comparisons require the host name, and can be done
3265 using the general string matching function. When this function is called for
3266 outgoing hosts, the name is always given explicitly. If it is NULL, it means we
3267 must use sender_host_name and its aliases, looking them up if necessary. */
3269 if (cb->host_name != NULL) /* Explicit host name given */
3270 return match_check_string(cb->host_name, ss, -1, TRUE, TRUE, TRUE,
3273 /* Host name not given; in principle we need the sender host name and its
3274 aliases. However, for query-style lookups, we do not need the name if the
3275 query does not contain $sender_host_name. From release 4.23, a reference to
3276 $sender_host_name causes it to be looked up, so we don't need to do the lookup
3279 if ((semicolon = Ustrchr(ss, ';')) != NULL)
3281 const uschar *affix;
3282 int partial, affixlen, starflags, id;
3285 id = search_findtype_partial(ss, &partial, &affix, &affixlen, &starflags);
3288 if (id < 0) /* Unknown lookup type */
3290 log_write(0, LOG_MAIN|LOG_PANIC, "%s in host list item \"%s\"",
3291 search_error_message, ss);
3294 isquery = mac_islookup(id, lookup_querystyle|lookup_absfilequery);
3299 switch(match_check_string(US"", ss, -1, TRUE, TRUE, TRUE, valueptr))
3302 case DEFER: return DEFER;
3303 default: return FAIL;
3307 /* Not a query-style lookup; must ensure the host name is present, and then we
3308 do a check on the name and all its aliases. */
3310 if (sender_host_name == NULL)
3312 HDEBUG(D_host_lookup)
3313 debug_printf("sender host name required, to match against %s\n", ss);
3314 if (host_lookup_failed || host_name_lookup() != OK)
3316 *error = string_sprintf("failed to find host name for %s",
3317 sender_host_address);;
3320 host_build_sender_fullhost();
3323 /* Match on the sender host name, using the general matching function */
3325 switch(match_check_string(sender_host_name, ss, -1, TRUE, TRUE, TRUE,
3329 case DEFER: return DEFER;
3332 /* If there are aliases, try matching on them. */
3334 aliases = sender_host_aliases;
3335 while (*aliases != NULL)
3337 switch(match_check_string(*aliases++, ss, -1, TRUE, TRUE, TRUE, valueptr))
3340 case DEFER: return DEFER;
3349 /*************************************************
3350 * Check a specific host matches a host list *
3351 *************************************************/
3353 /* This function is passed a host list containing items in a number of
3354 different formats and the identity of a host. Its job is to determine whether
3355 the given host is in the set of hosts defined by the list. The host name is
3356 passed as a pointer so that it can be looked up if needed and not already
3357 known. This is commonly the case when called from verify_check_host() to check
3358 an incoming connection. When called from elsewhere the host name should usually
3361 This function is now just a front end to match_check_list(), which runs common
3362 code for scanning a list. We pass it the check_host() function to perform a
3366 listptr pointer to the host list
3367 cache_bits pointer to cache for named lists, or NULL
3368 host_name the host name or NULL, implying use sender_host_name and
3369 sender_host_aliases, looking them up if required
3370 host_address the IP address
3371 valueptr if not NULL, data from a lookup is passed back here
3373 Returns: OK if the host is in the defined set
3374 FAIL if the host is not in the defined set,
3375 DEFER if a data lookup deferred (not a host lookup)
3377 If the host name was needed in order to make a comparison, and could not be
3378 determined from the IP address, the result is FAIL unless the item
3379 "+allow_unknown" was met earlier in the list, in which case OK is returned. */
3382 verify_check_this_host(const uschar **listptr, unsigned int *cache_bits,
3383 const uschar *host_name, const uschar *host_address, const uschar **valueptr)
3386 unsigned int *local_cache_bits = cache_bits;
3387 const uschar *save_host_address = deliver_host_address;
3388 check_host_block cb;
3389 cb.host_name = host_name;
3390 cb.host_address = host_address;
3392 if (valueptr != NULL) *valueptr = NULL;
3394 /* If the host address starts off ::ffff: it is an IPv6 address in
3395 IPv4-compatible mode. Find the IPv4 part for checking against IPv4
3398 cb.host_ipv4 = (Ustrncmp(host_address, "::ffff:", 7) == 0)?
3399 host_address + 7 : host_address;
3401 /* During the running of the check, put the IP address into $host_address. In
3402 the case of calls from the smtp transport, it will already be there. However,
3403 in other calls (e.g. when testing ignore_target_hosts), it won't. Just to be on
3404 the safe side, any existing setting is preserved, though as I write this
3405 (November 2004) I can't see any cases where it is actually needed. */
3407 deliver_host_address = host_address;
3408 rc = match_check_list(
3409 listptr, /* the list */
3410 0, /* separator character */
3411 &hostlist_anchor, /* anchor pointer */
3412 &local_cache_bits, /* cache pointer */
3413 check_host, /* function for testing */
3414 &cb, /* argument for function */
3415 MCL_HOST, /* type of check */
3416 (host_address == sender_host_address)?
3417 US"host" : host_address, /* text for debugging */
3418 valueptr); /* where to pass back data */
3419 deliver_host_address = save_host_address;
3426 /*************************************************
3427 * Check the given host item matches a list *
3428 *************************************************/
3430 verify_check_given_host(uschar **listptr, host_item *host)
3432 return verify_check_this_host(CUSS listptr, NULL, host->name, host->address, NULL);
3435 /*************************************************
3436 * Check the remote host matches a list *
3437 *************************************************/
3439 /* This is a front end to verify_check_this_host(), created because checking
3440 the remote host is a common occurrence. With luck, a good compiler will spot
3441 the tail recursion and optimize it. If there's no host address, this is
3442 command-line SMTP input - check against an empty string for the address.
3445 listptr pointer to the host list
3447 Returns: the yield of verify_check_this_host(),
3448 i.e. OK, FAIL, or DEFER
3452 verify_check_host(uschar **listptr)
3454 return verify_check_this_host(CUSS listptr, sender_host_cache, NULL,
3455 (sender_host_address == NULL)? US"" : sender_host_address, NULL);
3462 /*************************************************
3463 * Invert an IP address *
3464 *************************************************/
3466 /* Originally just used for DNS xBL lists, now also used for the
3467 reverse_ip expansion operator.
3470 buffer where to put the answer
3471 address the address to invert
3475 invert_address(uschar *buffer, uschar *address)
3478 uschar *bptr = buffer;
3480 /* If this is an IPv4 address mapped into IPv6 format, adjust the pointer
3481 to the IPv4 part only. */
3483 if (Ustrncmp(address, "::ffff:", 7) == 0) address += 7;
3485 /* Handle IPv4 address: when HAVE_IPV6 is false, the result of host_aton() is
3488 if (host_aton(address, bin) == 1)
3492 for (i = 0; i < 4; i++)
3494 sprintf(CS bptr, "%d.", x & 255);
3495 while (*bptr) bptr++;
3500 /* Handle IPv6 address. Actually, as far as I know, there are no IPv6 addresses
3501 in any DNS black lists, and the format in which they will be looked up is
3502 unknown. This is just a guess. */
3508 for (j = 3; j >= 0; j--)
3511 for (i = 0; i < 8; i++)
3513 sprintf(CS bptr, "%x.", x & 15);
3514 while (*bptr) bptr++;
3521 /* Remove trailing period -- this is needed so that both arbitrary
3522 dnsbl keydomains and inverted addresses may be combined with the
3523 same format string, "%s.%s" */
3530 /*************************************************
3531 * Perform a single dnsbl lookup *
3532 *************************************************/
3534 /* This function is called from verify_check_dnsbl() below. It is also called
3535 recursively from within itself when domain and domain_txt are different
3536 pointers, in order to get the TXT record from the alternate domain.
3539 domain the outer dnsbl domain
3540 domain_txt alternate domain to lookup TXT record on success; when the
3541 same domain is to be used, domain_txt == domain (that is,
3542 the pointers must be identical, not just the text)
3543 keydomain the current keydomain (for debug message)
3544 prepend subdomain to lookup (like keydomain, but
3545 reversed if IP address)
3546 iplist the list of matching IP addresses, or NULL for "any"
3547 bitmask true if bitmask matching is wanted
3548 match_type condition for 'succeed' result
3549 0 => Any RR in iplist (=)
3550 1 => No RR in iplist (!=)
3551 2 => All RRs in iplist (==)
3552 3 => Some RRs not in iplist (!==)
3553 the two bits are defined as MT_NOT and MT_ALL
3554 defer_return what to return for a defer
3556 Returns: OK if lookup succeeded
3561 one_check_dnsbl(uschar *domain, uschar *domain_txt, uschar *keydomain,
3562 uschar *prepend, uschar *iplist, BOOL bitmask, int match_type,
3568 dnsbl_cache_block *cb;
3569 int old_pool = store_pool;
3570 uschar query[256]; /* DNS domain max length */
3572 /* Construct the specific query domainname */
3574 if (!string_format(query, sizeof(query), "%s.%s", prepend, domain))
3576 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
3577 "(ignored): %s...", query);
3581 /* Look for this query in the cache. */
3583 if ( (t = tree_search(dnsbl_cache, query))
3584 && (cb = t->data.ptr)->expiry > time(NULL)
3587 /* Previous lookup was cached */
3590 HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
3593 /* If not cached from a previous lookup, we must do a DNS lookup, and
3594 cache the result in permanent memory. */
3600 store_pool = POOL_PERM;
3604 HDEBUG(D_dnsbl) debug_printf("cached data found but past valid time; ");
3608 { /* Set up a tree entry to cache the lookup */
3609 t = store_get(sizeof(tree_node) + Ustrlen(query));
3610 Ustrcpy(t->name, query);
3611 t->data.ptr = cb = store_get(sizeof(dnsbl_cache_block));
3612 (void)tree_insertnode(&dnsbl_cache, t);
3615 /* Do the DNS loopup . */
3617 HDEBUG(D_dnsbl) debug_printf("new DNS lookup for %s\n", query);
3618 cb->rc = dns_basic_lookup(&dnsa, query, T_A);
3619 cb->text_set = FALSE;
3623 /* If the lookup succeeded, cache the RHS address. The code allows for
3624 more than one address - this was for complete generality and the possible
3625 use of A6 records. However, A6 records have been reduced to experimental
3626 status (August 2001) and may die out. So they may never get used at all,
3627 let alone in dnsbl records. However, leave the code here, just in case.
3629 Quite apart from one A6 RR generating multiple addresses, there are DNS
3630 lists that return more than one A record, so we must handle multiple
3631 addresses generated in that way as well.
3633 Mark the cache entry with the "now" plus the minimum of the address TTLs,
3634 or some suitably far-future time if none were found. */
3636 if (cb->rc == DNS_SUCCEED)
3639 dns_address **addrp = &(cb->rhs);
3640 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
3642 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3644 if (rr->type == T_A)
3646 dns_address *da = dns_address_from_rr(&dnsa, rr);
3650 while (da->next != NULL) da = da->next;
3651 addrp = &(da->next);
3652 if (ttl > rr->ttl) ttl = rr->ttl;
3657 /* If we didn't find any A records, change the return code. This can
3658 happen when there is a CNAME record but there are no A records for what
3661 if (cb->rhs == NULL) cb->rc = DNS_NODATA;
3664 cb->expiry = time(NULL)+ttl;
3665 store_pool = old_pool;
3668 /* We now have the result of the DNS lookup, either newly done, or cached
3669 from a previous call. If the lookup succeeded, check against the address
3670 list if there is one. This may be a positive equality list (introduced by
3671 "="), a negative equality list (introduced by "!="), a positive bitmask
3672 list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/
3674 if (cb->rc == DNS_SUCCEED)
3676 dns_address *da = NULL;
3677 uschar *addlist = cb->rhs->address;
3679 /* For A and AAAA records, there may be multiple addresses from multiple
3680 records. For A6 records (currently not expected to be used) there may be
3681 multiple addresses from a single record. */
3683 for (da = cb->rhs->next; da != NULL; da = da->next)
3684 addlist = string_sprintf("%s, %s", addlist, da->address);
3686 HDEBUG(D_dnsbl) debug_printf("DNS lookup for %s succeeded (yielding %s)\n",
3689 /* Address list check; this can be either for equality, or via a bitmask.
3690 In the latter case, all the bits must match. */
3694 for (da = cb->rhs; da != NULL; da = da->next)
3698 const uschar *ptr = iplist;
3701 /* Handle exact matching */
3705 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))) != NULL)
3707 if (Ustrcmp(CS da->address, ip) == 0) break;
3711 /* Handle bitmask matching */
3718 /* At present, all known DNS blocking lists use A records, with
3719 IPv4 addresses on the RHS encoding the information they return. I
3720 wonder if this will linger on as the last vestige of IPv4 when IPv6
3721 is ubiquitous? Anyway, for now we use paranoia code to completely
3722 ignore IPv6 addresses. The default mask is 0, which always matches.
3723 We change this only for IPv4 addresses in the list. */
3725 if (host_aton(da->address, address) == 1) mask = address[0];
3727 /* Scan the returned addresses, skipping any that are IPv6 */
3729 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))) != NULL)
3731 if (host_aton(ip, address) != 1) continue;
3732 if ((address[0] & mask) == address[0]) break;
3738 (a) An IP address in an any ('=') list matched, or
3739 (b) No IP address in an all ('==') list matched
3741 then we're done searching. */
3743 if (((match_type & MT_ALL) != 0) == (res == NULL)) break;
3746 /* If da == NULL, either
3748 (a) No IP address in an any ('=') list matched, or
3749 (b) An IP address in an all ('==') list didn't match
3751 so behave as if the DNSBL lookup had not succeeded, i.e. the host is not on
3754 if ((match_type == MT_NOT || match_type == MT_ALL) != (da == NULL))
3762 res = US"was no match";
3765 res = US"was an exclude match";
3768 res = US"was an IP address that did not match";
3771 res = US"were no IP addresses that did not match";
3774 debug_printf("=> but we are not accepting this block class because\n");
3775 debug_printf("=> there %s for %s%c%s\n",
3777 ((match_type & MT_ALL) == 0)? "" : "=",
3778 bitmask? '&' : '=', iplist);
3784 /* Either there was no IP list, or the record matched, implying that the
3785 domain is on the list. We now want to find a corresponding TXT record. If an
3786 alternate domain is specified for the TXT record, call this function
3787 recursively to look that up; this has the side effect of re-checking that
3788 there is indeed an A record at the alternate domain. */
3790 if (domain_txt != domain)
3791 return one_check_dnsbl(domain_txt, domain_txt, keydomain, prepend, NULL,
3792 FALSE, match_type, defer_return);
3794 /* If there is no alternate domain, look up a TXT record in the main domain
3795 if it has not previously been cached. */
3799 cb->text_set = TRUE;
3800 if (dns_basic_lookup(&dnsa, query, T_TXT) == DNS_SUCCEED)
3803 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
3805 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3806 if (rr->type == T_TXT) break;
3809 int len = (rr->data)[0];
3810 if (len > 511) len = 127;
3811 store_pool = POOL_PERM;
3812 cb->text = string_sprintf("%.*s", len, (const uschar *)(rr->data+1));
3813 store_pool = old_pool;
3818 dnslist_value = addlist;
3819 dnslist_text = cb->text;
3823 /* There was a problem with the DNS lookup */
3825 if (cb->rc != DNS_NOMATCH && cb->rc != DNS_NODATA)
3827 log_write(L_dnslist_defer, LOG_MAIN,
3828 "DNS list lookup defer (probably timeout) for %s: %s", query,
3829 (defer_return == OK)? US"assumed in list" :
3830 (defer_return == FAIL)? US"assumed not in list" :
3831 US"returned DEFER");
3832 return defer_return;
3835 /* No entry was found in the DNS; continue for next domain */
3839 debug_printf("DNS lookup for %s failed\n", query);
3840 debug_printf("=> that means %s is not listed at %s\n",
3850 /*************************************************
3851 * Check host against DNS black lists *
3852 *************************************************/
3854 /* This function runs checks against a list of DNS black lists, until one
3855 matches. Each item on the list can be of the form
3857 domain=ip-address/key
3859 The domain is the right-most domain that is used for the query, for example,
3860 blackholes.mail-abuse.org. If the IP address is present, there is a match only
3861 if the DNS lookup returns a matching IP address. Several addresses may be
3862 given, comma-separated, for example: x.y.z=127.0.0.1,127.0.0.2.
3864 If no key is given, what is looked up in the domain is the inverted IP address
3865 of the current client host. If a key is given, it is used to construct the
3866 domain for the lookup. For example:
3868 dsn.rfc-ignorant.org/$sender_address_domain
3870 After finding a match in the DNS, the domain is placed in $dnslist_domain, and
3871 then we check for a TXT record for an error message, and if found, save its
3872 value in $dnslist_text. We also cache everything in a tree, to optimize
3875 The TXT record is normally looked up in the same domain as the A record, but
3876 when many lists are combined in a single DNS domain, this will not be a very
3877 specific message. It is possible to specify a different domain for looking up
3878 TXT records; this is given before the main domain, comma-separated. For
3881 dnslists = http.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.2 : \
3882 socks.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.3
3884 The caching ensures that only one lookup in dnsbl.sorbs.net is done.
3886 Note: an address for testing RBL is 192.203.178.39
3887 Note: an address for testing DUL is 192.203.178.4
3888 Note: a domain for testing RFCI is example.tld.dsn.rfc-ignorant.org
3892 listptr the domain/address/data list
3893 log_msgptr log message on error
3895 Returns: OK successful lookup (i.e. the address is on the list), or
3896 lookup deferred after +include_unknown
3897 FAIL name not found, or no data found for the given type, or
3898 lookup deferred after +exclude_unknown (default)
3899 DEFER lookup failure, if +defer_unknown was set
3903 verify_check_dnsbl(int where, const uschar ** listptr, uschar ** log_msgptr)
3906 int defer_return = FAIL;
3907 const uschar *list = *listptr;
3910 uschar buffer[1024];
3911 uschar revadd[128]; /* Long enough for IPv6 address */
3913 /* Indicate that the inverted IP address is not yet set up */
3917 /* In case this is the first time the DNS resolver is being used. */
3919 dns_init(FALSE, FALSE, FALSE); /*XXX dnssec? */
3921 /* Loop through all the domains supplied, until something matches */
3923 while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
3926 BOOL bitmask = FALSE;
3933 HDEBUG(D_dnsbl) debug_printf("DNS list check: %s\n", domain);
3935 /* Deal with special values that change the behaviour on defer */
3937 if (domain[0] == '+')
3939 if (strcmpic(domain, US"+include_unknown") == 0) defer_return = OK;
3940 else if (strcmpic(domain, US"+exclude_unknown") == 0) defer_return = FAIL;
3941 else if (strcmpic(domain, US"+defer_unknown") == 0) defer_return = DEFER;
3943 log_write(0, LOG_MAIN|LOG_PANIC, "unknown item in dnslist (ignored): %s",
3948 /* See if there's explicit data to be looked up */
3950 if ((key = Ustrchr(domain, '/'))) *key++ = 0;
3952 /* See if there's a list of addresses supplied after the domain name. This is
3953 introduced by an = or a & character; if preceded by = we require all matches
3954 and if preceded by ! we invert the result. */
3956 if (!(iplist = Ustrchr(domain, '=')))
3959 iplist = Ustrchr(domain, '&');
3962 if (iplist) /* Found either = or & */
3964 if (iplist > domain && iplist[-1] == '!') /* Handle preceding ! */
3966 match_type |= MT_NOT;
3970 *iplist++ = 0; /* Terminate domain, move on */
3972 /* If we found = (bitmask == FALSE), check for == or =& */
3974 if (!bitmask && (*iplist == '=' || *iplist == '&'))
3976 bitmask = *iplist++ == '&';
3977 match_type |= MT_ALL;
3982 /* If there is a comma in the domain, it indicates that a second domain for
3983 looking up TXT records is provided, before the main domain. Otherwise we must
3984 set domain_txt == domain. */
3986 domain_txt = domain;
3987 comma = Ustrchr(domain, ',');
3994 /* Check that what we have left is a sensible domain name. There is no reason
3995 why these domains should in fact use the same syntax as hosts and email
3996 domains, but in practice they seem to. However, there is little point in
3997 actually causing an error here, because that would no doubt hold up incoming
3998 mail. Instead, I'll just log it. */
4000 for (s = domain; *s != 0; s++)
4002 if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_')
4004 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
4005 "strange characters - is this right?", domain);
4010 /* Check the alternate domain if present */
4012 if (domain_txt != domain) for (s = domain_txt; *s != 0; s++)
4014 if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_')
4016 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
4017 "strange characters - is this right?", domain_txt);
4022 /* If there is no key string, construct the query by adding the domain name
4023 onto the inverted host address, and perform a single DNS lookup. */
4027 if (where == ACL_WHERE_NOTSMTP_START || where == ACL_WHERE_NOTSMTP)
4029 *log_msgptr = string_sprintf
4030 ("cannot test auto-keyed dnslists condition in %s ACL",
4031 acl_wherenames[where]);
4034 if (sender_host_address == NULL) return FAIL; /* can never match */
4035 if (revadd[0] == 0) invert_address(revadd, sender_host_address);
4036 rc = one_check_dnsbl(domain, domain_txt, sender_host_address, revadd,
4037 iplist, bitmask, match_type, defer_return);
4040 dnslist_domain = string_copy(domain_txt);
4041 dnslist_matched = string_copy(sender_host_address);
4042 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
4043 sender_host_address, dnslist_domain);
4045 if (rc != FAIL) return rc; /* OK or DEFER */
4048 /* If there is a key string, it can be a list of domains or IP addresses to
4049 be concatenated with the main domain. */
4056 uschar keybuffer[256];
4057 uschar keyrevadd[128];
4059 while ((keydomain = string_nextinlist(CUSS &key, &keysep, keybuffer,
4060 sizeof(keybuffer))) != NULL)
4062 uschar *prepend = keydomain;
4064 if (string_is_ip_address(keydomain, NULL) != 0)
4066 invert_address(keyrevadd, keydomain);
4067 prepend = keyrevadd;
4070 rc = one_check_dnsbl(domain, domain_txt, keydomain, prepend, iplist,
4071 bitmask, match_type, defer_return);
4075 dnslist_domain = string_copy(domain_txt);
4076 dnslist_matched = string_copy(keydomain);
4077 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
4078 keydomain, dnslist_domain);
4082 /* If the lookup deferred, remember this fact. We keep trying the rest
4083 of the list to see if we get a useful result, and if we don't, we return
4084 DEFER at the end. */
4086 if (rc == DEFER) defer = TRUE;
4087 } /* continue with next keystring domain/address */
4089 if (defer) return DEFER;
4091 } /* continue with next dnsdb outer domain */
4098 /* End of verify.c */