8a4867b94e945c15a52d277df2ebedff39001eee
[exim.git] / src / src / verify.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2016 */
6 /* See the file NOTICE for conditions of use and distribution. */
7
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). */
10
11
12 #include "exim.h"
13 #include "transports/smtp.h"
14
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];
19
20
21 /* Structure for caching DNSBL lookups */
22
23 typedef struct dnsbl_cache_block {
24 time_t expiry;
25 dns_address *rhs;
26 uschar *text;
27 int rc;
28 BOOL text_set;
29 } dnsbl_cache_block;
30
31
32 /* Anchor for DNSBL cache */
33
34 static tree_node *dnsbl_cache = NULL;
35
36
37 /* Bits for match_type in one_check_dnsbl() */
38
39 #define MT_NOT 1
40 #define MT_ALL 2
41
42 static uschar cutthrough_response(char, uschar **);
43
44
45 /*************************************************
46 * Retrieve a callout cache record *
47 *************************************************/
48
49 /* If a record exists, check whether it has expired.
50
51 Arguments:
52 dbm_file an open hints file
53 key the record key
54 type "address" or "domain"
55 positive_expire expire time for positive records
56 negative_expire expire time for negative records
57
58 Returns: the cache record if a non-expired one exists, else NULL
59 */
60
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)
64 {
65 BOOL negative;
66 int length, expire;
67 time_t now;
68 dbdata_callout_cache *cache_record;
69
70 cache_record = dbfn_read_with_length(dbm_file, key, &length);
71
72 if (cache_record == NULL)
73 {
74 HDEBUG(D_verify) debug_printf("callout cache: no %s record found for %s\n", type, key);
75 return NULL;
76 }
77
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. */
80
81 negative = cache_record->result != ccache_accept ||
82 (type[0] == 'd' && cache_record->postmaster_result == ccache_reject);
83 expire = negative? negative_expire : positive_expire;
84 now = time(NULL);
85
86 if (now - cache_record->time_stamp > expire)
87 {
88 HDEBUG(D_verify) debug_printf("callout cache: %s record expired for %s\n", type, key);
89 return NULL;
90 }
91
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.) */
97
98 if (type[0] == 'd' && cache_record->result != ccache_reject)
99 {
100 if (length == sizeof(dbdata_callout_cache_obs))
101 {
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;
105 cache_record = new;
106 }
107
108 if (now - cache_record->postmaster_stamp > expire)
109 cache_record->postmaster_result = ccache_unknown;
110
111 if (now - cache_record->random_stamp > expire)
112 cache_record->random_result = ccache_unknown;
113 }
114
115 HDEBUG(D_verify) debug_printf("callout cache: found %s record for %s\n", type, key);
116 return cache_record;
117 }
118
119
120
121 /*************************************************
122 * Do callout verification for an address *
123 *************************************************/
124
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.
128
129 Arguments:
130 addr the address that's been routed
131 host_list the list of hosts to try
132 tf the transport feedback block
133
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
149
150 Returns: OK/FAIL/DEFER
151 */
152
153 static int
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)
157 {
158 BOOL is_recipient = (options & vopt_is_recipient) != 0;
159 BOOL callout_no_cache = (options & vopt_callout_no_cache) != 0;
160 BOOL callout_random = (options & vopt_callout_random) != 0;
161
162 int yield = OK;
163 int old_domain_cache_result = ccache_accept;
164 BOOL done = FALSE;
165 uschar *address_key;
166 uschar *from_address;
167 uschar *random_local_part = NULL;
168 const uschar *save_deliver_domain = deliver_domain;
169 uschar **failure_ptr = is_recipient?
170 &recipient_verify_failure : &sender_verify_failure;
171 open_db dbblock;
172 open_db *dbm_file = NULL;
173 dbdata_callout_cache new_domain_record;
174 dbdata_callout_cache_address new_address_record;
175 host_item *host;
176 time_t callout_start_time;
177 uschar peer_offered = 0;
178
179 new_domain_record.result = ccache_unknown;
180 new_domain_record.postmaster_result = ccache_unknown;
181 new_domain_record.random_result = ccache_unknown;
182
183 memset(&new_address_record, 0, sizeof(new_address_record));
184
185 /* For a recipient callout, the key used for the address cache record must
186 include the sender address if we are using the real sender in the callout,
187 because that may influence the result of the callout. */
188
189 address_key = addr->address;
190 from_address = US"";
191
192 if (is_recipient)
193 {
194 if (options & vopt_callout_recipsender)
195 {
196 address_key = string_sprintf("%s/<%s>", addr->address, sender_address);
197 from_address = sender_address;
198 }
199 else if (options & vopt_callout_recippmaster)
200 {
201 address_key = string_sprintf("%s/<postmaster@%s>", addr->address,
202 qualify_domain_sender);
203 from_address = string_sprintf("postmaster@%s", qualify_domain_sender);
204 }
205 }
206
207 /* For a sender callout, we must adjust the key if the mailfrom address is not
208 empty. */
209
210 else
211 {
212 from_address = (se_mailfrom == NULL)? US"" : se_mailfrom;
213 if (from_address[0] != 0)
214 address_key = string_sprintf("%s/<%s>", addr->address, from_address);
215 }
216
217 /* Open the callout cache database, it it exists, for reading only at this
218 stage, unless caching has been disabled. */
219
220 if (callout_no_cache)
221 {
222 HDEBUG(D_verify) debug_printf("callout cache: disabled by no_cache\n");
223 }
224 else if ((dbm_file = dbfn_open(US"callout", O_RDWR, &dbblock, FALSE)) == NULL)
225 {
226 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
227 }
228
229 /* If a cache database is available see if we can avoid the need to do an
230 actual callout by making use of previously-obtained data. */
231
232 if (dbm_file != NULL)
233 {
234 dbdata_callout_cache_address *cache_address_record;
235 dbdata_callout_cache *cache_record = get_callout_cache_record(dbm_file,
236 addr->domain, US"domain",
237 callout_cache_domain_positive_expire,
238 callout_cache_domain_negative_expire);
239
240 /* If an unexpired cache record was found for this domain, see if the callout
241 process can be short-circuited. */
242
243 if (cache_record != NULL)
244 {
245 /* In most cases, if an early command (up to and including MAIL FROM:<>)
246 was rejected, there is no point carrying on. The callout fails. However, if
247 we are doing a recipient verification with use_sender or use_postmaster
248 set, a previous failure of MAIL FROM:<> doesn't count, because this time we
249 will be using a non-empty sender. We have to remember this situation so as
250 not to disturb the cached domain value if this whole verification succeeds
251 (we don't want it turning into "accept"). */
252
253 old_domain_cache_result = cache_record->result;
254
255 if (cache_record->result == ccache_reject ||
256 (*from_address == 0 && cache_record->result == ccache_reject_mfnull))
257 {
258 setflag(addr, af_verify_nsfail);
259 HDEBUG(D_verify)
260 debug_printf("callout cache: domain gave initial rejection, or "
261 "does not accept HELO or MAIL FROM:<>\n");
262 setflag(addr, af_verify_nsfail);
263 addr->user_message = US"(result of an earlier callout reused).";
264 yield = FAIL;
265 *failure_ptr = US"mail";
266 goto END_CALLOUT;
267 }
268
269 /* If a previous check on a "random" local part was accepted, we assume
270 that the server does not do any checking on local parts. There is therefore
271 no point in doing the callout, because it will always be successful. If a
272 random check previously failed, arrange not to do it again, but preserve
273 the data in the new record. If a random check is required but hasn't been
274 done, skip the remaining cache processing. */
275
276 if (callout_random) switch(cache_record->random_result)
277 {
278 case ccache_accept:
279 HDEBUG(D_verify)
280 debug_printf("callout cache: domain accepts random addresses\n");
281 goto END_CALLOUT; /* Default yield is OK */
282
283 case ccache_reject:
284 HDEBUG(D_verify)
285 debug_printf("callout cache: domain rejects random addresses\n");
286 callout_random = FALSE;
287 new_domain_record.random_result = ccache_reject;
288 new_domain_record.random_stamp = cache_record->random_stamp;
289 break;
290
291 default:
292 HDEBUG(D_verify)
293 debug_printf("callout cache: need to check random address handling "
294 "(not cached or cache expired)\n");
295 goto END_CACHE;
296 }
297
298 /* If a postmaster check is requested, but there was a previous failure,
299 there is again no point in carrying on. If a postmaster check is required,
300 but has not been done before, we are going to have to do a callout, so skip
301 remaining cache processing. */
302
303 if (pm_mailfrom != NULL)
304 {
305 if (cache_record->postmaster_result == ccache_reject)
306 {
307 setflag(addr, af_verify_pmfail);
308 HDEBUG(D_verify)
309 debug_printf("callout cache: domain does not accept "
310 "RCPT TO:<postmaster@domain>\n");
311 yield = FAIL;
312 *failure_ptr = US"postmaster";
313 setflag(addr, af_verify_pmfail);
314 addr->user_message = US"(result of earlier verification reused).";
315 goto END_CALLOUT;
316 }
317 if (cache_record->postmaster_result == ccache_unknown)
318 {
319 HDEBUG(D_verify)
320 debug_printf("callout cache: need to check RCPT "
321 "TO:<postmaster@domain> (not cached or cache expired)\n");
322 goto END_CACHE;
323 }
324
325 /* If cache says OK, set pm_mailfrom NULL to prevent a redundant
326 postmaster check if the address itself has to be checked. Also ensure
327 that the value in the cache record is preserved (with its old timestamp).
328 */
329
330 HDEBUG(D_verify) debug_printf("callout cache: domain accepts RCPT "
331 "TO:<postmaster@domain>\n");
332 pm_mailfrom = NULL;
333 new_domain_record.postmaster_result = ccache_accept;
334 new_domain_record.postmaster_stamp = cache_record->postmaster_stamp;
335 }
336 }
337
338 /* We can't give a result based on information about the domain. See if there
339 is an unexpired cache record for this specific address (combined with the
340 sender address if we are doing a recipient callout with a non-empty sender).
341 */
342
343 cache_address_record = (dbdata_callout_cache_address *)
344 get_callout_cache_record(dbm_file,
345 address_key, US"address",
346 callout_cache_positive_expire,
347 callout_cache_negative_expire);
348
349 if (cache_address_record != NULL)
350 {
351 if (cache_address_record->result == ccache_accept)
352 {
353 HDEBUG(D_verify)
354 debug_printf("callout cache: address record is positive\n");
355 }
356 else
357 {
358 HDEBUG(D_verify)
359 debug_printf("callout cache: address record is negative\n");
360 addr->user_message = US"Previous (cached) callout verification failure";
361 *failure_ptr = US"recipient";
362 yield = FAIL;
363 }
364 goto END_CALLOUT;
365 }
366
367 /* Close the cache database while we actually do the callout for real. */
368
369 END_CACHE:
370 dbfn_close(dbm_file);
371 dbm_file = NULL;
372 }
373
374 if (!addr->transport)
375 {
376 HDEBUG(D_verify) debug_printf("cannot callout via null transport\n");
377 }
378 else if (Ustrcmp(addr->transport->driver_name, "smtp") != 0)
379 log_write(0, LOG_MAIN|LOG_PANIC|LOG_CONFIG_FOR, "callout transport '%s': %s is non-smtp",
380 addr->transport->name, addr->transport->driver_name);
381 else
382 {
383 smtp_transport_options_block *ob =
384 (smtp_transport_options_block *)addr->transport->options_block;
385
386 /* The information wasn't available in the cache, so we have to do a real
387 callout and save the result in the cache for next time, unless no_cache is set,
388 or unless we have a previously cached negative random result. If we are to test
389 with a random local part, ensure that such a local part is available. If not,
390 log the fact, but carry on without randomming. */
391
392 if (callout_random && callout_random_local_part != NULL)
393 if (!(random_local_part = expand_string(callout_random_local_part)))
394 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand "
395 "callout_random_local_part: %s", expand_string_message);
396
397 /* Default the connect and overall callout timeouts if not set, and record the
398 time we are starting so that we can enforce it. */
399
400 if (callout_overall < 0) callout_overall = 4 * callout;
401 if (callout_connect < 0) callout_connect = callout;
402 callout_start_time = time(NULL);
403
404 /* Before doing a real callout, if this is an SMTP connection, flush the SMTP
405 output because a callout might take some time. When PIPELINING is active and
406 there are many recipients, the total time for doing lots of callouts can add up
407 and cause the client to time out. So in this case we forgo the PIPELINING
408 optimization. */
409
410 if (smtp_out != NULL && !disable_callout_flush) mac_smtp_fflush();
411
412 /* cutthrough-multi: if a nonfirst rcpt has the same routing as the first,
413 and we are holding a cutthrough conn open, we can just append the rcpt to
414 that conn for verification purposes (and later delivery also). Simplest
415 coding means skipping this whole loop and doing the append separately.
416
417 We will need to remember it has been appended so that rcpt-acl tail code
418 can do it there for the non-rcpt-verify case. For this we keep an addresscount.
419 */
420
421 /* Can we re-use an open cutthrough connection? */
422 if ( cutthrough.fd >= 0
423 && (options & (vopt_callout_recipsender | vopt_callout_recippmaster))
424 == vopt_callout_recipsender
425 && !random_local_part
426 && !pm_mailfrom
427 )
428 {
429 if (addr->transport == cutthrough.addr.transport)
430 for (host = host_list; host; host = host->next)
431 if (Ustrcmp(host->address, cutthrough.host.address) == 0)
432 {
433 int host_af;
434 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
435 int port = 25;
436
437 deliver_host = host->name;
438 deliver_host_address = host->address;
439 deliver_host_port = host->port;
440 deliver_domain = addr->domain;
441 transport_name = addr->transport->name;
442
443 host_af = (Ustrchr(host->address, ':') == NULL)? AF_INET:AF_INET6;
444
445 if (!smtp_get_interface(tf->interface, host_af, addr, &interface,
446 US"callout") ||
447 !smtp_get_port(tf->port, addr, &port, US"callout"))
448 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
449 addr->message);
450
451 if ( ( interface == cutthrough.interface
452 || ( interface
453 && cutthrough.interface
454 && Ustrcmp(interface, cutthrough.interface) == 0
455 ) )
456 && port == cutthrough.host.port
457 )
458 {
459 uschar * resp = NULL;
460
461 /* Match! Send the RCPT TO, append the addr, set done */
462 done =
463 smtp_write_command(&ctblock, FALSE, "RCPT TO:<%.1000s>\r\n",
464 transport_rcpt_address(addr,
465 (addr->transport == NULL)? FALSE :
466 addr->transport->rcpt_include_affixes)) >= 0 &&
467 cutthrough_response('2', &resp) == '2';
468
469 /* This would go horribly wrong if a callout fail was ignored by ACL.
470 We punt by abandoning cutthrough on a reject, like the
471 first-rcpt does. */
472
473 if (done)
474 {
475 address_item * na = store_get(sizeof(address_item));
476 *na = cutthrough.addr;
477 cutthrough.addr = *addr;
478 cutthrough.addr.host_used = &cutthrough.host;
479 cutthrough.addr.next = na;
480
481 cutthrough.nrcpt++;
482 }
483 else
484 {
485 cancel_cutthrough_connection("recipient rejected");
486 if (!resp || errno == ETIMEDOUT)
487 {
488 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
489 }
490 else if (errno == 0)
491 {
492 if (*resp == 0)
493 Ustrcpy(resp, US"connection dropped");
494
495 addr->message =
496 string_sprintf("response to \"%s\" from %s [%s] was: %s",
497 big_buffer, host->name, host->address,
498 string_printing(resp));
499
500 addr->user_message =
501 string_sprintf("Callout verification failed:\n%s", resp);
502
503 /* Hard rejection ends the process */
504
505 if (resp[0] == '5') /* Address rejected */
506 {
507 yield = FAIL;
508 done = TRUE;
509 }
510 }
511 }
512 }
513 break;
514 }
515 if (!done)
516 cancel_cutthrough_connection("incompatible connection");
517 }
518
519 /* Now make connections to the hosts and do real callouts. The list of hosts
520 is passed in as an argument. */
521
522 for (host = host_list; host != NULL && !done; host = host->next)
523 {
524 smtp_inblock inblock;
525 smtp_outblock outblock;
526 int host_af;
527 int port = 25;
528 BOOL send_quit = TRUE;
529 uschar *active_hostname = smtp_active_hostname;
530 BOOL lmtp;
531 BOOL smtps;
532 BOOL esmtp;
533 BOOL suppress_tls = FALSE;
534 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
535 #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_DANE)
536 BOOL dane = FALSE;
537 BOOL dane_required;
538 dns_answer tlsa_dnsa;
539 #endif
540 uschar inbuffer[4096];
541 uschar outbuffer[1024];
542 uschar responsebuffer[4096];
543 uschar * size_str;
544
545 clearflag(addr, af_verify_pmfail); /* postmaster callout flag */
546 clearflag(addr, af_verify_nsfail); /* null sender callout flag */
547
548 /* Skip this host if we don't have an IP address for it. */
549
550 if (host->address == NULL)
551 {
552 DEBUG(D_verify) debug_printf("no IP address for host name %s: skipping\n",
553 host->name);
554 continue;
555 }
556
557 /* Check the overall callout timeout */
558
559 if (time(NULL) - callout_start_time >= callout_overall)
560 {
561 HDEBUG(D_verify) debug_printf("overall timeout for callout exceeded\n");
562 break;
563 }
564
565 /* Set IPv4 or IPv6 */
566
567 host_af = (Ustrchr(host->address, ':') == NULL)? AF_INET:AF_INET6;
568
569 /* Expand and interpret the interface and port strings. The latter will not
570 be used if there is a host-specific port (e.g. from a manualroute router).
571 This has to be delayed till now, because they may expand differently for
572 different hosts. If there's a failure, log it, but carry on with the
573 defaults. */
574
575 deliver_host = host->name;
576 deliver_host_address = host->address;
577 deliver_host_port = host->port;
578 deliver_domain = addr->domain;
579 transport_name = addr->transport->name;
580
581 if ( !smtp_get_interface(tf->interface, host_af, addr, &interface,
582 US"callout")
583 || !smtp_get_port(tf->port, addr, &port, US"callout")
584 )
585 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
586 addr->message);
587
588 /* Set HELO string according to the protocol */
589 lmtp= Ustrcmp(tf->protocol, "lmtp") == 0;
590 smtps= Ustrcmp(tf->protocol, "smtps") == 0;
591
592
593 HDEBUG(D_verify) debug_printf("interface=%s port=%d\n", interface, port);
594
595 /* Set up the buffer for reading SMTP response packets. */
596
597 inblock.buffer = inbuffer;
598 inblock.buffersize = sizeof(inbuffer);
599 inblock.ptr = inbuffer;
600 inblock.ptrend = inbuffer;
601
602 /* Set up the buffer for holding SMTP commands while pipelining */
603
604 outblock.buffer = outbuffer;
605 outblock.buffersize = sizeof(outbuffer);
606 outblock.ptr = outbuffer;
607 outblock.cmd_count = 0;
608 outblock.authenticating = FALSE;
609
610 /* Connect to the host; on failure, just loop for the next one, but we
611 set the error for the last one. Use the callout_connect timeout. */
612
613 tls_retry_connection:
614
615 /* Reset the parameters of a TLS session */
616 tls_out.cipher = tls_out.peerdn = tls_out.peercert = NULL;
617
618 inblock.sock = outblock.sock =
619 smtp_connect(host, host_af, port, interface, callout_connect,
620 addr->transport);
621 if (inblock.sock < 0)
622 {
623 addr->message = string_sprintf("could not connect to %s [%s]: %s",
624 host->name, host->address, strerror(errno));
625 transport_name = NULL;
626 deliver_host = deliver_host_address = NULL;
627 deliver_domain = save_deliver_domain;
628 continue;
629 }
630
631 #if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_DANE)
632 {
633 int rc;
634
635 tls_out.dane_verified = FALSE;
636 tls_out.tlsa_usage = 0;
637
638 dane_required =
639 verify_check_given_host(&ob->hosts_require_dane, host) == OK;
640
641 if (host->dnssec == DS_YES)
642 {
643 if( dane_required
644 || verify_check_given_host(&ob->hosts_try_dane, host) == OK
645 )
646 {
647 if ((rc = tlsa_lookup(host, &tlsa_dnsa, dane_required)) != OK)
648 return rc;
649 dane = TRUE;
650 }
651 }
652 else if (dane_required)
653 {
654 log_write(0, LOG_MAIN, "DANE error: %s lookup not DNSSEC", host->name);
655 return FAIL;
656 }
657
658 if (dane)
659 ob->tls_tempfail_tryclear = FALSE;
660 }
661 #endif /*DANE*/
662
663 /* Expand the helo_data string to find the host name to use. */
664
665 if (tf->helo_data != NULL)
666 {
667 uschar *s = expand_string(tf->helo_data);
668 if (s == NULL)
669 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: failed to expand transport's "
670 "helo_data value for callout: %s", addr->address,
671 expand_string_message);
672 else active_hostname = s;
673 }
674
675 /* Wait for initial response, and send HELO. The smtp_write_command()
676 function leaves its command in big_buffer. This is used in error responses.
677 Initialize it in case the connection is rejected. */
678
679 Ustrcpy(big_buffer, "initial connection");
680
681 /* Unless ssl-on-connect, wait for the initial greeting */
682 smtps_redo_greeting:
683
684 #ifdef SUPPORT_TLS
685 if (!smtps || (smtps && tls_out.active >= 0))
686 #endif
687 {
688 if (!(done= smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), '2', callout)))
689 goto RESPONSE_FAILED;
690
691 #ifndef DISABLE_EVENT
692 lookup_dnssec_authenticated = host->dnssec==DS_YES ? US"yes"
693 : host->dnssec==DS_NO ? US"no" : NULL;
694 if (event_raise(addr->transport->event_action,
695 US"smtp:connect", responsebuffer))
696 {
697 lookup_dnssec_authenticated = NULL;
698 /* Logging? Debug? */
699 goto RESPONSE_FAILED;
700 }
701 lookup_dnssec_authenticated = NULL;
702 #endif
703 }
704
705 /* Not worth checking greeting line for ESMTP support */
706 if (!(esmtp = verify_check_given_host(&ob->hosts_avoid_esmtp, host) != OK))
707 DEBUG(D_transport)
708 debug_printf("not sending EHLO (host matches hosts_avoid_esmtp)\n");
709
710 tls_redo_helo:
711
712 #ifdef SUPPORT_TLS
713 if (smtps && tls_out.active < 0) /* ssl-on-connect, first pass */
714 {
715 peer_offered &= ~PEER_OFFERED_TLS;
716 ob->tls_tempfail_tryclear = FALSE;
717 }
718 else /* all other cases */
719 #endif
720
721 { esmtp_retry:
722
723 if (!(done= smtp_write_command(&outblock, FALSE, "%s %s\r\n",
724 !esmtp? "HELO" : lmtp? "LHLO" : "EHLO", active_hostname) >= 0))
725 goto SEND_FAILED;
726 if (!smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), '2', callout))
727 {
728 if (errno != 0 || responsebuffer[0] == 0 || lmtp || !esmtp || tls_out.active >= 0)
729 {
730 done= FALSE;
731 goto RESPONSE_FAILED;
732 }
733 #ifdef SUPPORT_TLS
734 peer_offered &= ~PEER_OFFERED_TLS;
735 #endif
736 esmtp = FALSE;
737 goto esmtp_retry; /* fallback to HELO */
738 }
739
740 /* Set tls_offered if the response to EHLO specifies support for STARTTLS. */
741
742 peer_offered = esmtp
743 ? ehlo_response(responsebuffer, sizeof(responsebuffer),
744 (!suppress_tls && tls_out.active < 0 ? PEER_OFFERED_TLS : 0)
745 | 0 /* no IGNQ */
746 | 0 /* no PRDR */
747 #ifdef SUPPORT_I18N
748 | (addr->prop.utf8_msg && !addr->prop.utf8_downcvt
749 ? PEER_OFFERED_UTF8 : 0)
750 #endif
751 | 0 /* no DSN */
752 | 0 /* no PIPE */
753
754 /* only care about SIZE if we have size from inbound */
755 | (message_size > 0 && ob->size_addition >= 0
756 ? PEER_OFFERED_SIZE : 0)
757 )
758 : 0;
759 }
760
761 size_str = peer_offered & PEER_OFFERED_SIZE
762 ? string_sprintf(" SIZE=%d", message_size + ob->size_addition) : US"";
763
764 #ifdef SUPPORT_TLS
765 tls_offered = !!(peer_offered & PEER_OFFERED_TLS);
766 #endif
767
768 /* If TLS is available on this connection attempt to
769 start up a TLS session, unless the host is in hosts_avoid_tls. If successful,
770 send another EHLO - the server may give a different answer in secure mode. We
771 use a separate buffer for reading the response to STARTTLS so that if it is
772 negative, the original EHLO data is available for subsequent analysis, should
773 the client not be required to use TLS. If the response is bad, copy the buffer
774 for error analysis. */
775
776 #ifdef SUPPORT_TLS
777 if ( peer_offered & PEER_OFFERED_TLS
778 && verify_check_given_host(&ob->hosts_avoid_tls, host) != OK
779 && verify_check_given_host(&ob->hosts_verify_avoid_tls, host) != OK
780 )
781 {
782 uschar buffer2[4096];
783 if ( !smtps
784 && !(done= smtp_write_command(&outblock, FALSE, "STARTTLS\r\n") >= 0))
785 goto SEND_FAILED;
786
787 /* If there is an I/O error, transmission of this message is deferred. If
788 there is a temporary rejection of STARRTLS and tls_tempfail_tryclear is
789 false, we also defer. However, if there is a temporary rejection of STARTTLS
790 and tls_tempfail_tryclear is true, or if there is an outright rejection of
791 STARTTLS, we carry on. This means we will try to send the message in clear,
792 unless the host is in hosts_require_tls (tested below). */
793
794 if (!smtps && !smtp_read_response(&inblock, buffer2, sizeof(buffer2), '2',
795 ob->command_timeout))
796 {
797 if ( errno != 0
798 || buffer2[0] == 0
799 || buffer2[0] == '4' && !ob->tls_tempfail_tryclear
800 )
801 {
802 Ustrncpy(responsebuffer, buffer2, sizeof(responsebuffer));
803 done= FALSE;
804 goto RESPONSE_FAILED;
805 }
806 }
807
808 /* STARTTLS accepted or ssl-on-connect: try to negotiate a TLS session. */
809 else
810 {
811 int oldtimeout = ob->command_timeout;
812 int rc;
813
814 tls_negotiate:
815 ob->command_timeout = callout;
816 rc = tls_client_start(inblock.sock, host, addr, addr->transport
817 # ifdef EXPERIMENTAL_DANE
818 , dane ? &tlsa_dnsa : NULL
819 # endif
820 );
821 ob->command_timeout = oldtimeout;
822
823 /* TLS negotiation failed; give an error. Try in clear on a new
824 connection, if the options permit it for this host. */
825 if (rc != OK)
826 {
827 if (rc == DEFER)
828 {
829 (void)close(inblock.sock);
830 # ifndef DISABLE_EVENT
831 (void) event_raise(addr->transport->event_action,
832 US"tcp:close", NULL);
833 # endif
834 if ( ob->tls_tempfail_tryclear
835 && !smtps
836 && verify_check_given_host(&ob->hosts_require_tls, host) != OK
837 )
838 {
839 log_write(0, LOG_MAIN, "TLS session failure:"
840 " delivering unencrypted to %s [%s] (not in hosts_require_tls)",
841 host->name, host->address);
842 suppress_tls = TRUE;
843 goto tls_retry_connection;
844 }
845 }
846
847 /*save_errno = ERRNO_TLSFAILURE;*/
848 /*message = US"failure while setting up TLS session";*/
849 send_quit = FALSE;
850 done= FALSE;
851 goto TLS_FAILED;
852 }
853
854 /* TLS session is set up. Copy info for logging. */
855 addr->cipher = tls_out.cipher;
856 addr->peerdn = tls_out.peerdn;
857
858 /* For SMTPS we need to wait for the initial OK response, then do HELO. */
859 if (smtps)
860 goto smtps_redo_greeting;
861
862 /* For STARTTLS we need to redo EHLO */
863 goto tls_redo_helo;
864 }
865 }
866
867 /* If the host is required to use a secure channel, ensure that we have one. */
868 if (tls_out.active < 0)
869 if (
870 # ifdef EXPERIMENTAL_DANE
871 dane ||
872 # endif
873 verify_check_given_host(&ob->hosts_require_tls, host) == OK
874 )
875 {
876 /*save_errno = ERRNO_TLSREQUIRED;*/
877 log_write(0, LOG_MAIN,
878 "H=%s [%s]: a TLS session is required for this host, but %s",
879 host->name, host->address,
880 peer_offered & PEER_OFFERED_TLS
881 ? "an attempt to start TLS failed"
882 : "the server did not offer TLS support");
883 done= FALSE;
884 goto TLS_FAILED;
885 }
886
887 #endif /*SUPPORT_TLS*/
888
889 done = TRUE; /* so far so good; have response to HELO */
890
891 /* For now, transport_filter by cutthrough-delivery is not supported */
892 /* Need proper integration with the proper transport mechanism. */
893 if (cutthrough.delivery)
894 {
895 if (addr->transport->filter_command)
896 {
897 cutthrough.delivery = FALSE;
898 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of transport filter\n");
899 }
900 #ifndef DISABLE_DKIM
901 if (ob->dkim_domain)
902 {
903 cutthrough.delivery = FALSE;
904 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of DKIM signing\n");
905 }
906 #endif
907 }
908
909 SEND_FAILED:
910 RESPONSE_FAILED:
911 TLS_FAILED:
912 ;
913 /* Clear down of the TLS, SMTP and TCP layers on error is handled below. */
914
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. */
917
918 if (!done)
919 {
920 *failure_ptr = US"mail"; /* At or before MAIL */
921 if (errno == 0 && responsebuffer[0] == '5')
922 {
923 setflag(addr, af_verify_nsfail);
924 new_domain_record.result = ccache_reject;
925 }
926 }
927
928 #ifdef SUPPORT_I18N
929 else if ( addr->prop.utf8_msg
930 && !addr->prop.utf8_downcvt
931 && !(peer_offered & PEER_OFFERED_UTF8)
932 )
933 {
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);
937 done = FALSE;
938 }
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,
943 &addr->message),
944 addr->message
945 ) )
946 {
947 errno = ERRNO_EXPANDFAIL;
948 setflag(addr, af_verify_nsfail);
949 done = FALSE;
950 }
951 #endif
952
953 /* If we haven't authenticated, but are required to, give up. */
954 /* Try to AUTH */
955
956 else done = smtp_auth(responsebuffer, sizeof(responsebuffer),
957 addr, host, ob, esmtp, &inblock, &outblock) == OK &&
958
959 /* Copy AUTH info for logging */
960 ( (addr->authenticator = client_authenticator),
961 (addr->auth_id = client_authenticated_id),
962
963 /* Build a mail-AUTH string (re-using responsebuffer for convenience */
964 !smtp_mail_auth_str(responsebuffer, sizeof(responsebuffer), addr, ob)
965 ) &&
966
967 ( (addr->auth_sndr = client_authenticated_sender),
968
969 /* Send the MAIL command */
970 (smtp_write_command(&outblock, FALSE,
971 #ifdef SUPPORT_I18N
972 addr->prop.utf8_msg && !addr->prop.utf8_downcvt
973 ? "MAIL FROM:<%s>%s%s SMTPUTF8\r\n"
974 :
975 #endif
976 "MAIL FROM:<%s>%s%s\r\n",
977 from_address, responsebuffer, size_str) >= 0)
978 ) &&
979
980 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
981 '2', callout);
982
983 deliver_host = deliver_host_address = NULL;
984 deliver_domain = save_deliver_domain;
985
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. */
990
991 if (!done)
992 {
993 *failure_ptr = US"mail"; /* At or before MAIL */
994 if (errno == 0 && responsebuffer[0] == '5')
995 {
996 setflag(addr, af_verify_nsfail);
997 if (from_address[0] == 0)
998 new_domain_record.result = ccache_reject_mfnull;
999 }
1000 }
1001
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
1005 FROM:<>.
1006
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. */
1012
1013 else
1014 {
1015 const uschar * rcpt_domain = addr->domain;
1016
1017 #ifdef SUPPORT_I18N
1018 uschar * errstr = NULL;
1019 if ( testflag(addr, af_utf8_downcvt)
1020 && (rcpt_domain = string_domain_utf8_to_alabel(rcpt_domain,
1021 &errstr), errstr)
1022 )
1023 {
1024 addr->message = errstr;
1025 errno = ERRNO_EXPANDFAIL;
1026 setflag(addr, af_verify_nsfail);
1027 done = FALSE;
1028 rcpt_domain = US""; /*XXX errorhandling! */
1029 }
1030 #endif
1031
1032 new_domain_record.result =
1033 (old_domain_cache_result == ccache_reject_mfnull)?
1034 ccache_reject_mfnull: ccache_accept;
1035
1036 /* Do the random local part check first */
1037
1038 if (random_local_part != NULL)
1039 {
1040 uschar randombuffer[1024];
1041 BOOL random_ok =
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);
1047
1048 /* Remember when we last did a random test */
1049
1050 new_domain_record.random_stamp = time(NULL);
1051
1052 /* If accepted, we aren't going to do any further tests below. */
1053
1054 if (random_ok)
1055 new_domain_record.random_result = ccache_accept;
1056
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.
1062 */
1063
1064 else if (errno == 0)
1065 {
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");
1069
1070 if (randombuffer[0] == '5')
1071 new_domain_record.random_result = ccache_reject;
1072
1073 done =
1074 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
1075 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
1076 '2', callout) &&
1077
1078 smtp_write_command(&outblock, FALSE,
1079 #ifdef SUPPORT_I18N
1080 addr->prop.utf8_msg && !addr->prop.utf8_downcvt
1081 ? "MAIL FROM:<%s> SMTPUTF8\r\n"
1082 :
1083 #endif
1084 "MAIL FROM:<%s>\r\n",
1085 from_address) >= 0 &&
1086 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
1087 '2', callout);
1088
1089 if (!done)
1090 {
1091 HDEBUG(D_acl|D_v)
1092 debug_printf("problem after random/rset/mfrom; reopen conn\n");
1093 random_local_part = NULL;
1094 #ifdef SUPPORT_TLS
1095 tls_close(FALSE, TRUE);
1096 #endif
1097 (void)close(inblock.sock);
1098 #ifndef DISABLE_EVENT
1099 (void) event_raise(addr->transport->event_action,
1100 US"tcp:close", NULL);
1101 #endif
1102 goto tls_retry_connection;
1103 }
1104 }
1105 else done = FALSE; /* Some timeout/connection problem */
1106 } /* Random check */
1107
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. */
1110
1111 if (new_domain_record.random_result != ccache_accept && done)
1112 {
1113 /* Get the rcpt_include_affixes flag from the transport if there is one,
1114 but assume FALSE if there is not. */
1115
1116 uschar * rcpt = transport_rcpt_address(addr,
1117 addr->transport ? addr->transport->rcpt_include_affixes : FALSE);
1118
1119 #ifdef SUPPORT_I18N
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),
1124 dummy_errstr
1125 ) )
1126 {
1127 errno = ERRNO_EXPANDFAIL;
1128 *failure_ptr = US"recipient";
1129 done = FALSE;
1130 }
1131 else
1132 #endif
1133
1134 done =
1135 smtp_write_command(&outblock, FALSE, "RCPT TO:<%.1000s>\r\n",
1136 rcpt) >= 0 &&
1137 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
1138 '2', callout);
1139
1140 if (done)
1141 new_address_record.result = ccache_accept;
1142 else if (errno == 0 && responsebuffer[0] == '5')
1143 {
1144 *failure_ptr = US"recipient";
1145 new_address_record.result = ccache_reject;
1146 }
1147
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. */
1150
1151 if (done && pm_mailfrom != NULL)
1152 {
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
1155 refuse any */
1156 cancel_cutthrough_connection("postmaster verify");
1157 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of postmaster verify\n");
1158
1159 done =
1160 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
1161 smtp_read_response(&inblock, responsebuffer,
1162 sizeof(responsebuffer), '2', callout) &&
1163
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) &&
1168
1169 /* First try using the current domain */
1170
1171 ((
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)
1176 )
1177
1178 ||
1179
1180 /* If that doesn't work, and a full check is requested,
1181 try without the domain. */
1182
1183 (
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)
1189 ));
1190
1191 /* Sort out the cache record */
1192
1193 new_domain_record.postmaster_stamp = time(NULL);
1194
1195 if (done)
1196 new_domain_record.postmaster_result = ccache_accept;
1197 else if (errno == 0 && responsebuffer[0] == '5')
1198 {
1199 *failure_ptr = US"postmaster";
1200 setflag(addr, af_verify_pmfail);
1201 new_domain_record.postmaster_result = ccache_reject;
1202 }
1203 }
1204 } /* Random not accepted */
1205 } /* MAIL FROM: accepted */
1206
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
1210
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. */
1216
1217 if (!done)
1218 {
1219 if (errno == ETIMEDOUT)
1220 {
1221 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
1222 send_quit = FALSE;
1223 }
1224 #ifdef SUPPORT_I18N
1225 else if (errno == ERRNO_UTF8_FWD)
1226 {
1227 extern int acl_where; /* src/acl.c */
1228 errno = 0;
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";
1235 yield = FAIL;
1236 done = TRUE;
1237 }
1238 #endif
1239 else if (errno == 0)
1240 {
1241 if (*responsebuffer == 0) Ustrcpy(responsebuffer, US"connection dropped");
1242
1243 addr->message =
1244 string_sprintf("response to \"%s\" from %s [%s] was: %s",
1245 big_buffer, host->name, host->address,
1246 string_printing(responsebuffer));
1247
1248 addr->user_message = is_recipient?
1249 string_sprintf("Callout verification failed:\n%s", responsebuffer)
1250 :
1251 string_sprintf("Called: %s\nSent: %s\nResponse: %s",
1252 host->address, big_buffer, responsebuffer);
1253
1254 /* Hard rejection ends the process */
1255
1256 if (responsebuffer[0] == '5') /* Address rejected */
1257 {
1258 yield = FAIL;
1259 done = TRUE;
1260 }
1261 }
1262 }
1263
1264 /* End the SMTP conversation and close the connection. */
1265
1266 /* Cutthrough - on a successfull connect and recipient-verify with
1267 use-sender and we are 1st rcpt and have no cutthrough conn so far
1268 here is where we want to leave the conn open */
1269 if ( cutthrough.delivery
1270 && rcpt_count == 1
1271 && done
1272 && yield == OK
1273 && (options & (vopt_callout_recipsender|vopt_callout_recippmaster)) == vopt_callout_recipsender
1274 && !random_local_part
1275 && !pm_mailfrom
1276 && cutthrough.fd < 0
1277 && !lmtp
1278 )
1279 {
1280 cutthrough.fd = outblock.sock; /* We assume no buffer in use in the outblock */
1281 cutthrough.nrcpt = 1;
1282 cutthrough.interface = interface;
1283 cutthrough.host = *host;
1284 cutthrough.addr = *addr; /* Save the address_item for later logging */
1285 cutthrough.addr.next = NULL;
1286 cutthrough.addr.host_used = &cutthrough.host;
1287 if (addr->parent)
1288 *(cutthrough.addr.parent = store_get(sizeof(address_item))) =
1289 *addr->parent;
1290 ctblock.buffer = ctbuffer;
1291 ctblock.buffersize = sizeof(ctbuffer);
1292 ctblock.ptr = ctbuffer;
1293 /* ctblock.cmd_count = 0; ctblock.authenticating = FALSE; */
1294 ctblock.sock = cutthrough.fd;
1295 }
1296 else
1297 {
1298 /* Ensure no cutthrough on multiple address verifies */
1299 if (options & vopt_callout_recipsender)
1300 cancel_cutthrough_connection("multiple verify calls");
1301 if (send_quit) (void)smtp_write_command(&outblock, FALSE, "QUIT\r\n");
1302
1303 #ifdef SUPPORT_TLS
1304 tls_close(FALSE, TRUE);
1305 #endif
1306 (void)close(inblock.sock);
1307 #ifndef DISABLE_EVENT
1308 (void) event_raise(addr->transport->event_action, US"tcp:close", NULL);
1309 #endif
1310 }
1311
1312 } /* Loop through all hosts, while !done */
1313 }
1314
1315 /* If we get here with done == TRUE, a successful callout happened, and yield
1316 will be set OK or FAIL according to the response to the RCPT command.
1317 Otherwise, we looped through the hosts but couldn't complete the business.
1318 However, there may be domain-specific information to cache in both cases.
1319
1320 The value of the result field in the new_domain record is ccache_unknown if
1321 there was an error before or with MAIL FROM:, and errno was not zero,
1322 implying some kind of I/O error. We don't want to write the cache in that case.
1323 Otherwise the value is ccache_accept, ccache_reject, or ccache_reject_mfnull. */
1324
1325 if (!callout_no_cache && new_domain_record.result != ccache_unknown)
1326 {
1327 if ((dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE))
1328 == NULL)
1329 {
1330 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
1331 }
1332 else
1333 {
1334 (void)dbfn_write(dbm_file, addr->domain, &new_domain_record,
1335 (int)sizeof(dbdata_callout_cache));
1336 HDEBUG(D_verify) debug_printf("wrote callout cache domain record:\n"
1337 " result=%d postmaster=%d random=%d\n",
1338 new_domain_record.result,
1339 new_domain_record.postmaster_result,
1340 new_domain_record.random_result);
1341 }
1342 }
1343
1344 /* If a definite result was obtained for the callout, cache it unless caching
1345 is disabled. */
1346
1347 if (done)
1348 {
1349 if (!callout_no_cache && new_address_record.result != ccache_unknown)
1350 {
1351 if (dbm_file == NULL)
1352 dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE);
1353 if (dbm_file == NULL)
1354 {
1355 HDEBUG(D_verify) debug_printf("no callout cache available\n");
1356 }
1357 else
1358 {
1359 (void)dbfn_write(dbm_file, address_key, &new_address_record,
1360 (int)sizeof(dbdata_callout_cache_address));
1361 HDEBUG(D_verify) debug_printf("wrote %s callout cache address record\n",
1362 (new_address_record.result == ccache_accept)? "positive" : "negative");
1363 }
1364 }
1365 } /* done */
1366
1367 /* Failure to connect to any host, or any response other than 2xx or 5xx is a
1368 temporary error. If there was only one host, and a response was received, leave
1369 it alone if supplying details. Otherwise, give a generic response. */
1370
1371 else /* !done */
1372 {
1373 uschar *dullmsg = string_sprintf("Could not complete %s verify callout",
1374 is_recipient? "recipient" : "sender");
1375 yield = DEFER;
1376
1377 if (host_list->next != NULL || addr->message == NULL) addr->message = dullmsg;
1378
1379 addr->user_message = (!smtp_return_error_details)? dullmsg :
1380 string_sprintf("%s for <%s>.\n"
1381 "The mail server(s) for the domain may be temporarily unreachable, or\n"
1382 "they may be permanently unreachable from this server. In the latter case,\n%s",
1383 dullmsg, addr->address,
1384 is_recipient?
1385 "the address will never be accepted."
1386 :
1387 "you need to change the address or create an MX record for its domain\n"
1388 "if it is supposed to be generally accessible from the Internet.\n"
1389 "Talk to your mail administrator for details.");
1390
1391 /* Force a specific error code */
1392
1393 addr->basic_errno = ERRNO_CALLOUTDEFER;
1394 }
1395
1396 /* Come here from within the cache-reading code on fast-track exit. */
1397
1398 END_CALLOUT:
1399 if (dbm_file != NULL) dbfn_close(dbm_file);
1400 return yield;
1401 }
1402
1403
1404
1405 /* Called after recipient-acl to get a cutthrough connection open when
1406 one was requested and a recipient-verify wasn't subsequently done.
1407 */
1408 int
1409 open_cutthrough_connection( address_item * addr )
1410 {
1411 address_item addr2;
1412 int rc;
1413
1414 /* Use a recipient-verify-callout to set up the cutthrough connection. */
1415 /* We must use a copy of the address for verification, because it might
1416 get rewritten. */
1417
1418 addr2 = *addr;
1419 HDEBUG(D_acl) debug_printf("----------- %s cutthrough setup ------------\n",
1420 rcpt_count > 1 ? "more" : "start");
1421 rc= verify_address(&addr2, NULL,
1422 vopt_is_recipient | vopt_callout_recipsender | vopt_callout_no_cache,
1423 CUTTHROUGH_CMD_TIMEOUT, -1, -1,
1424 NULL, NULL, NULL);
1425 HDEBUG(D_acl) debug_printf("----------- end cutthrough setup ------------\n");
1426 return rc;
1427 }
1428
1429
1430
1431 /* Send given number of bytes from the buffer */
1432 static BOOL
1433 cutthrough_send(int n)
1434 {
1435 if(cutthrough.fd < 0)
1436 return TRUE;
1437
1438 if(
1439 #ifdef SUPPORT_TLS
1440 (tls_out.active == cutthrough.fd) ? tls_write(FALSE, ctblock.buffer, n) :
1441 #endif
1442 send(cutthrough.fd, ctblock.buffer, n, 0) > 0
1443 )
1444 {
1445 transport_count += n;
1446 ctblock.ptr= ctblock.buffer;
1447 return TRUE;
1448 }
1449
1450 HDEBUG(D_transport|D_acl) debug_printf("cutthrough_send failed: %s\n", strerror(errno));
1451 return FALSE;
1452 }
1453
1454
1455
1456 static BOOL
1457 _cutthrough_puts(uschar * cp, int n)
1458 {
1459 while(n--)
1460 {
1461 if(ctblock.ptr >= ctblock.buffer+ctblock.buffersize)
1462 if(!cutthrough_send(ctblock.buffersize))
1463 return FALSE;
1464
1465 *ctblock.ptr++ = *cp++;
1466 }
1467 return TRUE;
1468 }
1469
1470 /* Buffered output of counted data block. Return boolean success */
1471 BOOL
1472 cutthrough_puts(uschar * cp, int n)
1473 {
1474 if (cutthrough.fd < 0) return TRUE;
1475 if (_cutthrough_puts(cp, n)) return TRUE;
1476 cancel_cutthrough_connection("transmit failed");
1477 return FALSE;
1478 }
1479
1480
1481 static BOOL
1482 _cutthrough_flush_send(void)
1483 {
1484 int n= ctblock.ptr-ctblock.buffer;
1485
1486 if(n>0)
1487 if(!cutthrough_send(n))
1488 return FALSE;
1489 return TRUE;
1490 }
1491
1492
1493 /* Send out any bufferred output. Return boolean success. */
1494 BOOL
1495 cutthrough_flush_send(void)
1496 {
1497 if (_cutthrough_flush_send()) return TRUE;
1498 cancel_cutthrough_connection("transmit failed");
1499 return FALSE;
1500 }
1501
1502
1503 BOOL
1504 cutthrough_put_nl(void)
1505 {
1506 return cutthrough_puts(US"\r\n", 2);
1507 }
1508
1509
1510 /* Get and check response from cutthrough target */
1511 static uschar
1512 cutthrough_response(char expect, uschar ** copy)
1513 {
1514 smtp_inblock inblock;
1515 uschar inbuffer[4096];
1516 uschar responsebuffer[4096];
1517
1518 inblock.buffer = inbuffer;
1519 inblock.buffersize = sizeof(inbuffer);
1520 inblock.ptr = inbuffer;
1521 inblock.ptrend = inbuffer;
1522 inblock.sock = cutthrough.fd;
1523 /* this relies on (inblock.sock == tls_out.active) */
1524 if(!smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), expect, CUTTHROUGH_DATA_TIMEOUT))
1525 cancel_cutthrough_connection("target timeout on read");
1526
1527 if(copy != NULL)
1528 {
1529 uschar * cp;
1530 *copy = cp = string_copy(responsebuffer);
1531 /* Trim the trailing end of line */
1532 cp += Ustrlen(responsebuffer);
1533 if(cp > *copy && cp[-1] == '\n') *--cp = '\0';
1534 if(cp > *copy && cp[-1] == '\r') *--cp = '\0';
1535 }
1536
1537 return responsebuffer[0];
1538 }
1539
1540
1541 /* Negotiate dataphase with the cutthrough target, returning success boolean */
1542 BOOL
1543 cutthrough_predata(void)
1544 {
1545 if(cutthrough.fd < 0)
1546 return FALSE;
1547
1548 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> DATA\n");
1549 cutthrough_puts(US"DATA\r\n", 6);
1550 cutthrough_flush_send();
1551
1552 /* Assume nothing buffered. If it was it gets ignored. */
1553 return cutthrough_response('3', NULL) == '3';
1554 }
1555
1556
1557 /* fd and use_crlf args only to match write_chunk() */
1558 static BOOL
1559 cutthrough_write_chunk(int fd, uschar * s, int len, BOOL use_crlf)
1560 {
1561 uschar * s2;
1562 while(s && (s2 = Ustrchr(s, '\n')))
1563 {
1564 if(!cutthrough_puts(s, s2-s) || !cutthrough_put_nl())
1565 return FALSE;
1566 s = s2+1;
1567 }
1568 return TRUE;
1569 }
1570
1571
1572 /* Buffered send of headers. Return success boolean. */
1573 /* Expands newlines to wire format (CR,NL). */
1574 /* Also sends header-terminating blank line. */
1575 BOOL
1576 cutthrough_headers_send(void)
1577 {
1578 if(cutthrough.fd < 0)
1579 return FALSE;
1580
1581 /* We share a routine with the mainline transport to handle header add/remove/rewrites,
1582 but having a separate buffered-output function (for now)
1583 */
1584 HDEBUG(D_acl) debug_printf("----------- start cutthrough headers send -----------\n");
1585
1586 if (!transport_headers_send(&cutthrough.addr, cutthrough.fd,
1587 cutthrough.addr.transport->add_headers,
1588 cutthrough.addr.transport->remove_headers,
1589 &cutthrough_write_chunk, TRUE,
1590 cutthrough.addr.transport->rewrite_rules,
1591 cutthrough.addr.transport->rewrite_existflags))
1592 return FALSE;
1593
1594 HDEBUG(D_acl) debug_printf("----------- done cutthrough headers send ------------\n");
1595 return TRUE;
1596 }
1597
1598
1599 static void
1600 close_cutthrough_connection(const char * why)
1601 {
1602 if(cutthrough.fd >= 0)
1603 {
1604 /* We could be sending this after a bunch of data, but that is ok as
1605 the only way to cancel the transfer in dataphase is to drop the tcp
1606 conn before the final dot.
1607 */
1608 ctblock.ptr = ctbuffer;
1609 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> QUIT\n");
1610 _cutthrough_puts(US"QUIT\r\n", 6); /* avoid recursion */
1611 _cutthrough_flush_send();
1612 /* No wait for response */
1613
1614 #ifdef SUPPORT_TLS
1615 tls_close(FALSE, TRUE);
1616 #endif
1617 (void)close(cutthrough.fd);
1618 cutthrough.fd = -1;
1619 HDEBUG(D_acl) debug_printf("----------- cutthrough shutdown (%s) ------------\n", why);
1620 }
1621 ctblock.ptr = ctbuffer;
1622 }
1623
1624 void
1625 cancel_cutthrough_connection(const char * why)
1626 {
1627 close_cutthrough_connection(why);
1628 cutthrough.delivery = FALSE;
1629 }
1630
1631
1632
1633
1634 /* Have senders final-dot. Send one to cutthrough target, and grab the response.
1635 Log an OK response as a transmission.
1636 Close the connection.
1637 Return smtp response-class digit.
1638 */
1639 uschar *
1640 cutthrough_finaldot(void)
1641 {
1642 uschar res;
1643 address_item * addr;
1644 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> .\n");
1645
1646 /* Assume data finshed with new-line */
1647 if( !cutthrough_puts(US".", 1)
1648 || !cutthrough_put_nl()
1649 || !cutthrough_flush_send()
1650 )
1651 return cutthrough.addr.message;
1652
1653 res = cutthrough_response('2', &cutthrough.addr.message);
1654 for (addr = &cutthrough.addr; addr; addr = addr->next)
1655 {
1656 addr->message = cutthrough.addr.message;
1657 switch(res)
1658 {
1659 case '2':
1660 delivery_log(LOG_MAIN, addr, (int)'>', NULL);
1661 close_cutthrough_connection("delivered");
1662 break;
1663
1664 case '4':
1665 delivery_log(LOG_MAIN, addr, 0,
1666 US"tmp-reject from cutthrough after DATA:");
1667 break;
1668
1669 case '5':
1670 delivery_log(LOG_MAIN|LOG_REJECT, addr, 0,
1671 US"rejected after DATA:");
1672 break;
1673
1674 default:
1675 break;
1676 }
1677 }
1678 return cutthrough.addr.message;
1679 }
1680
1681
1682
1683 /*************************************************
1684 * Copy error to toplevel address *
1685 *************************************************/
1686
1687 /* This function is used when a verify fails or defers, to ensure that the
1688 failure or defer information is in the original toplevel address. This applies
1689 when an address is redirected to a single new address, and the failure or
1690 deferral happens to the child address.
1691
1692 Arguments:
1693 vaddr the verify address item
1694 addr the final address item
1695 yield FAIL or DEFER
1696
1697 Returns: the value of YIELD
1698 */
1699
1700 static int
1701 copy_error(address_item *vaddr, address_item *addr, int yield)
1702 {
1703 if (addr != vaddr)
1704 {
1705 vaddr->message = addr->message;
1706 vaddr->user_message = addr->user_message;
1707 vaddr->basic_errno = addr->basic_errno;
1708 vaddr->more_errno = addr->more_errno;
1709 vaddr->prop.address_data = addr->prop.address_data;
1710 copyflag(vaddr, addr, af_pass_message);
1711 }
1712 return yield;
1713 }
1714
1715
1716
1717
1718 /**************************************************
1719 * printf that automatically handles TLS if needed *
1720 ***************************************************/
1721
1722 /* This function is used by verify_address() as a substitute for all fprintf()
1723 calls; a direct fprintf() will not produce output in a TLS SMTP session, such
1724 as a response to an EXPN command. smtp_in.c makes smtp_printf available but
1725 that assumes that we always use the smtp_out FILE* when not using TLS or the
1726 ssl buffer when we are. Instead we take a FILE* parameter and check to see if
1727 that is smtp_out; if so, smtp_printf() with TLS support, otherwise regular
1728 fprintf().
1729
1730 Arguments:
1731 f the candidate FILE* to write to
1732 format format string
1733 ... optional arguments
1734
1735 Returns:
1736 nothing
1737 */
1738
1739 static void PRINTF_FUNCTION(2,3)
1740 respond_printf(FILE *f, const char *format, ...)
1741 {
1742 va_list ap;
1743
1744 va_start(ap, format);
1745 if (smtp_out && (f == smtp_out))
1746 smtp_vprintf(format, ap);
1747 else
1748 vfprintf(f, format, ap);
1749 va_end(ap);
1750 }
1751
1752
1753
1754 /*************************************************
1755 * Verify an email address *
1756 *************************************************/
1757
1758 /* This function is used both for verification (-bv and at other times) and
1759 address testing (-bt), which is indicated by address_test_mode being set.
1760
1761 Arguments:
1762 vaddr contains the address to verify; the next field in this block
1763 must be NULL
1764 f if not NULL, write the result to this file
1765 options various option bits:
1766 vopt_fake_sender => this sender verify is not for the real
1767 sender (it was verify=sender=xxxx or an address from a
1768 header line) - rewriting must not change sender_address
1769 vopt_is_recipient => this is a recipient address, otherwise
1770 it's a sender address - this affects qualification and
1771 rewriting and messages from callouts
1772 vopt_qualify => qualify an unqualified address; else error
1773 vopt_expn => called from SMTP EXPN command
1774 vopt_success_on_redirect => when a new address is generated
1775 the verification instantly succeeds
1776
1777 These ones are used by do_callout() -- the options variable
1778 is passed to it.
1779
1780 vopt_callout_fullpm => if postmaster check, do full one
1781 vopt_callout_no_cache => don't use callout cache
1782 vopt_callout_random => do the "random" thing
1783 vopt_callout_recipsender => use real sender for recipient
1784 vopt_callout_recippmaster => use postmaster for recipient
1785
1786 callout if > 0, specifies that callout is required, and gives timeout
1787 for individual commands
1788 callout_overall if > 0, gives overall timeout for the callout function;
1789 if < 0, a default is used (see do_callout())
1790 callout_connect the connection timeout for callouts
1791 se_mailfrom when callout is requested to verify a sender, use this
1792 in MAIL FROM; NULL => ""
1793 pm_mailfrom when callout is requested, if non-NULL, do the postmaster
1794 thing and use this as the sender address (may be "")
1795
1796 routed if not NULL, set TRUE if routing succeeded, so we can
1797 distinguish between routing failed and callout failed
1798
1799 Returns: OK address verified
1800 FAIL address failed to verify
1801 DEFER can't tell at present
1802 */
1803
1804 int
1805 verify_address(address_item *vaddr, FILE *f, int options, int callout,
1806 int callout_overall, int callout_connect, uschar *se_mailfrom,
1807 uschar *pm_mailfrom, BOOL *routed)
1808 {
1809 BOOL allok = TRUE;
1810 BOOL full_info = (f == NULL)? FALSE : (debug_selector != 0);
1811 BOOL is_recipient = (options & vopt_is_recipient) != 0;
1812 BOOL expn = (options & vopt_expn) != 0;
1813 BOOL success_on_redirect = (options & vopt_success_on_redirect) != 0;
1814 int i;
1815 int yield = OK;
1816 int verify_type = expn? v_expn :
1817 address_test_mode? v_none :
1818 is_recipient? v_recipient : v_sender;
1819 address_item *addr_list;
1820 address_item *addr_new = NULL;
1821 address_item *addr_remote = NULL;
1822 address_item *addr_local = NULL;
1823 address_item *addr_succeed = NULL;
1824 uschar **failure_ptr = is_recipient?
1825 &recipient_verify_failure : &sender_verify_failure;
1826 uschar *ko_prefix, *cr;
1827 uschar *address = vaddr->address;
1828 uschar *save_sender;
1829 uschar null_sender[] = { 0 }; /* Ensure writeable memory */
1830
1831 /* Clear, just in case */
1832
1833 *failure_ptr = NULL;
1834
1835 /* Set up a prefix and suffix for error message which allow us to use the same
1836 output statements both in EXPN mode (where an SMTP response is needed) and when
1837 debugging with an output file. */
1838
1839 if (expn)
1840 {
1841 ko_prefix = US"553 ";
1842 cr = US"\r";
1843 }
1844 else ko_prefix = cr = US"";
1845
1846 /* Add qualify domain if permitted; otherwise an unqualified address fails. */
1847
1848 if (parse_find_at(address) == NULL)
1849 {
1850 if ((options & vopt_qualify) == 0)
1851 {
1852 if (f != NULL)
1853 respond_printf(f, "%sA domain is required for \"%s\"%s\n",
1854 ko_prefix, address, cr);
1855 *failure_ptr = US"qualify";
1856 return FAIL;
1857 }
1858 address = rewrite_address_qualify(address, is_recipient);
1859 }
1860
1861 DEBUG(D_verify)
1862 {
1863 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1864 debug_printf("%s %s\n", address_test_mode? "Testing" : "Verifying", address);
1865 }
1866
1867 /* Rewrite and report on it. Clear the domain and local part caches - these
1868 may have been set by domains and local part tests during an ACL. */
1869
1870 if (global_rewrite_rules != NULL)
1871 {
1872 uschar *old = address;
1873 address = rewrite_address(address, is_recipient, FALSE,
1874 global_rewrite_rules, rewrite_existflags);
1875 if (address != old)
1876 {
1877 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->localpart_cache[i] = 0;
1878 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->domain_cache[i] = 0;
1879 if (f != NULL && !expn) fprintf(f, "Address rewritten as: %s\n", address);
1880 }
1881 }
1882
1883 /* If this is the real sender address, we must update sender_address at
1884 this point, because it may be referred to in the routers. */
1885
1886 if ((options & (vopt_fake_sender|vopt_is_recipient)) == 0)
1887 sender_address = address;
1888
1889 /* If the address was rewritten to <> no verification can be done, and we have
1890 to return OK. This rewriting is permitted only for sender addresses; for other
1891 addresses, such rewriting fails. */
1892
1893 if (address[0] == 0) return OK;
1894
1895 /* Flip the legacy TLS-related variables over to the outbound set in case
1896 they're used in the context of a transport used by verification. Reset them
1897 at exit from this routine (so no returns allowed from here on). */
1898
1899 tls_modify_variables(&tls_out);
1900
1901 /* Save a copy of the sender address for re-instating if we change it to <>
1902 while verifying a sender address (a nice bit of self-reference there). */
1903
1904 save_sender = sender_address;
1905
1906 /* Observability variable for router/transport use */
1907
1908 verify_mode = is_recipient ? US"R" : US"S";
1909
1910 /* Update the address structure with the possibly qualified and rewritten
1911 address. Set it up as the starting address on the chain of new addresses. */
1912
1913 vaddr->address = address;
1914 addr_new = vaddr;
1915
1916 /* We need a loop, because an address can generate new addresses. We must also
1917 cope with generated pipes and files at the top level. (See also the code and
1918 comment in deliver.c.) However, it is usually the case that the router for
1919 user's .forward files has its verify flag turned off.
1920
1921 If an address generates more than one child, the loop is used only when
1922 full_info is set, and this can only be set locally. Remote enquiries just get
1923 information about the top level address, not anything that it generated. */
1924
1925 while (addr_new)
1926 {
1927 int rc;
1928 address_item *addr = addr_new;
1929
1930 addr_new = addr->next;
1931 addr->next = NULL;
1932
1933 DEBUG(D_verify)
1934 {
1935 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1936 debug_printf("Considering %s\n", addr->address);
1937 }
1938
1939 /* Handle generated pipe, file or reply addresses. We don't get these
1940 when handling EXPN, as it does only one level of expansion. */
1941
1942 if (testflag(addr, af_pfr))
1943 {
1944 allok = FALSE;
1945 if (f != NULL)
1946 {
1947 BOOL allow;
1948
1949 if (addr->address[0] == '>')
1950 {
1951 allow = testflag(addr, af_allow_reply);
1952 fprintf(f, "%s -> mail %s", addr->parent->address, addr->address + 1);
1953 }
1954 else
1955 {
1956 allow = (addr->address[0] == '|')?
1957 testflag(addr, af_allow_pipe) : testflag(addr, af_allow_file);
1958 fprintf(f, "%s -> %s", addr->parent->address, addr->address);
1959 }
1960
1961 if (addr->basic_errno == ERRNO_BADTRANSPORT)
1962 fprintf(f, "\n*** Error in setting up pipe, file, or autoreply:\n"
1963 "%s\n", addr->message);
1964 else if (allow)
1965 fprintf(f, "\n transport = %s\n", addr->transport->name);
1966 else
1967 fprintf(f, " *** forbidden ***\n");
1968 }
1969 continue;
1970 }
1971
1972 /* Just in case some router parameter refers to it. */
1973
1974 return_path = addr->prop.errors_address
1975 ? addr->prop.errors_address : sender_address;
1976
1977 /* Split the address into domain and local part, handling the %-hack if
1978 necessary, and then route it. While routing a sender address, set
1979 $sender_address to <> because that is what it will be if we were trying to
1980 send a bounce to the sender. */
1981
1982 if (routed) *routed = FALSE;
1983 if ((rc = deliver_split_address(addr)) == OK)
1984 {
1985 if (!is_recipient) sender_address = null_sender;
1986 rc = route_address(addr, &addr_local, &addr_remote, &addr_new,
1987 &addr_succeed, verify_type);
1988 sender_address = save_sender; /* Put back the real sender */
1989 }
1990
1991 /* If routing an address succeeded, set the flag that remembers, for use when
1992 an ACL cached a sender verify (in case a callout fails). Then if routing set
1993 up a list of hosts or the transport has a host list, and the callout option
1994 is set, and we aren't in a host checking run, do the callout verification,
1995 and set another flag that notes that a callout happened. */
1996
1997 if (rc == OK)
1998 {
1999 if (routed) *routed = TRUE;
2000 if (callout > 0)
2001 {
2002 transport_instance * tp;
2003 host_item * host_list = addr->host_list;
2004
2005 /* Make up some data for use in the case where there is no remote
2006 transport. */
2007
2008 transport_feedback tf = {
2009 NULL, /* interface (=> any) */
2010 US"smtp", /* port */
2011 US"smtp", /* protocol */
2012 NULL, /* hosts */
2013 US"$smtp_active_hostname", /* helo_data */
2014 FALSE, /* hosts_override */
2015 FALSE, /* hosts_randomize */
2016 FALSE, /* gethostbyname */
2017 TRUE, /* qualify_single */
2018 FALSE /* search_parents */
2019 };
2020
2021 /* If verification yielded a remote transport, we want to use that
2022 transport's options, so as to mimic what would happen if we were really
2023 sending a message to this address. */
2024
2025 if ((tp = addr->transport) && !tp->info->local)
2026 {
2027 (void)(tp->setup)(tp, addr, &tf, 0, 0, NULL);
2028
2029 /* If the transport has hosts and the router does not, or if the
2030 transport is configured to override the router's hosts, we must build a
2031 host list of the transport's hosts, and find the IP addresses */
2032
2033 if (tf.hosts && (!host_list || tf.hosts_override))
2034 {
2035 uschar *s;
2036 const uschar *save_deliver_domain = deliver_domain;
2037 uschar *save_deliver_localpart = deliver_localpart;
2038
2039 host_list = NULL; /* Ignore the router's hosts */
2040
2041 deliver_domain = addr->domain;
2042 deliver_localpart = addr->local_part;
2043 s = expand_string(tf.hosts);
2044 deliver_domain = save_deliver_domain;
2045 deliver_localpart = save_deliver_localpart;
2046
2047 if (!s)
2048 {
2049 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand list of hosts "
2050 "\"%s\" in %s transport for callout: %s", tf.hosts,
2051 tp->name, expand_string_message);
2052 }
2053 else
2054 {
2055 int flags;
2056 host_item *host, *nexthost;
2057 host_build_hostlist(&host_list, s, tf.hosts_randomize);
2058
2059 /* Just ignore failures to find a host address. If we don't manage
2060 to find any addresses, the callout will defer. Note that more than
2061 one address may be found for a single host, which will result in
2062 additional host items being inserted into the chain. Hence we must
2063 save the next host first. */
2064
2065 flags = HOST_FIND_BY_A;
2066 if (tf.qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
2067 if (tf.search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
2068
2069 for (host = host_list; host; host = nexthost)
2070 {
2071 nexthost = host->next;
2072 if (tf.gethostbyname ||
2073 string_is_ip_address(host->name, NULL) != 0)
2074 (void)host_find_byname(host, NULL, flags, NULL, TRUE);
2075 else
2076 {
2077 dnssec_domains * dnssec_domains = NULL;
2078 if (Ustrcmp(tp->driver_name, "smtp") == 0)
2079 {
2080 smtp_transport_options_block * ob =
2081 (smtp_transport_options_block *) tp->options_block;
2082 dnssec_domains = &ob->dnssec;
2083 }
2084
2085 (void)host_find_bydns(host, NULL, flags, NULL, NULL, NULL,
2086 dnssec_domains, NULL, NULL);
2087 }
2088 }
2089 }
2090 }
2091 }
2092
2093 /* Can only do a callout if we have at least one host! If the callout
2094 fails, it will have set ${sender,recipient}_verify_failure. */
2095
2096 if (host_list)
2097 {
2098 HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n");
2099 if (host_checking && !host_checking_callout)
2100 {
2101 HDEBUG(D_verify)
2102 debug_printf("... callout omitted by default when host testing\n"
2103 "(Use -bhc if you want the callouts to happen.)\n");
2104 }
2105 else
2106 {
2107 #ifdef SUPPORT_TLS
2108 deliver_set_expansions(addr);
2109 #endif
2110 rc = do_callout(addr, host_list, &tf, callout, callout_overall,
2111 callout_connect, options, se_mailfrom, pm_mailfrom);
2112 }
2113 }
2114 else
2115 {
2116 HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor "
2117 "transport provided a host list\n");
2118 }
2119 }
2120 }
2121
2122 /* Otherwise, any failure is a routing failure */
2123
2124 else *failure_ptr = US"route";
2125
2126 /* A router may return REROUTED if it has set up a child address as a result
2127 of a change of domain name (typically from widening). In this case we always
2128 want to continue to verify the new child. */
2129
2130 if (rc == REROUTED) continue;
2131
2132 /* Handle hard failures */
2133
2134 if (rc == FAIL)
2135 {
2136 allok = FALSE;
2137 if (f)
2138 {
2139 address_item *p = addr->parent;
2140
2141 respond_printf(f, "%s%s %s", ko_prefix,
2142 full_info ? addr->address : address,
2143 address_test_mode ? "is undeliverable" : "failed to verify");
2144 if (!expn && admin_user)
2145 {
2146 if (addr->basic_errno > 0)
2147 respond_printf(f, ": %s", strerror(addr->basic_errno));
2148 if (addr->message)
2149 respond_printf(f, ": %s", addr->message);
2150 }
2151
2152 /* Show parents iff doing full info */
2153
2154 if (full_info) while (p)
2155 {
2156 respond_printf(f, "%s\n <-- %s", cr, p->address);
2157 p = p->parent;
2158 }
2159 respond_printf(f, "%s\n", cr);
2160 }
2161 cancel_cutthrough_connection("routing hard fail");
2162
2163 if (!full_info)
2164 {
2165 yield = copy_error(vaddr, addr, FAIL);
2166 goto out;
2167 }
2168 yield = FAIL;
2169 }
2170
2171 /* Soft failure */
2172
2173 else if (rc == DEFER)
2174 {
2175 allok = FALSE;
2176 if (f)
2177 {
2178 address_item *p = addr->parent;
2179 respond_printf(f, "%s%s cannot be resolved at this time", ko_prefix,
2180 full_info? addr->address : address);
2181 if (!expn && admin_user)
2182 {
2183 if (addr->basic_errno > 0)
2184 respond_printf(f, ": %s", strerror(addr->basic_errno));
2185 if (addr->message)
2186 respond_printf(f, ": %s", addr->message);
2187 else if (addr->basic_errno <= 0)
2188 respond_printf(f, ": unknown error");
2189 }
2190
2191 /* Show parents iff doing full info */
2192
2193 if (full_info) while (p)
2194 {
2195 respond_printf(f, "%s\n <-- %s", cr, p->address);
2196 p = p->parent;
2197 }
2198 respond_printf(f, "%s\n", cr);
2199 }
2200 cancel_cutthrough_connection("routing soft fail");
2201
2202 if (!full_info)
2203 {
2204 yield = copy_error(vaddr, addr, DEFER);
2205 goto out;
2206 }
2207 if (yield == OK) yield = DEFER;
2208 }
2209
2210 /* If we are handling EXPN, we do not want to continue to route beyond
2211 the top level (whose address is in "address"). */
2212
2213 else if (expn)
2214 {
2215 uschar *ok_prefix = US"250-";
2216
2217 if (!addr_new)
2218 if (!addr_local && !addr_remote)
2219 respond_printf(f, "250 mail to <%s> is discarded\r\n", address);
2220 else
2221 respond_printf(f, "250 <%s>\r\n", address);
2222
2223 else do
2224 {
2225 address_item *addr2 = addr_new;
2226 addr_new = addr2->next;
2227 if (!addr_new) ok_prefix = US"250 ";
2228 respond_printf(f, "%s<%s>\r\n", ok_prefix, addr2->address);
2229 } while (addr_new);
2230 yield = OK;
2231 goto out;
2232 }
2233
2234 /* Successful routing other than EXPN. */
2235
2236 else
2237 {
2238 /* Handle successful routing when short info wanted. Otherwise continue for
2239 other (generated) addresses. Short info is the operational case. Full info
2240 can be requested only when debug_selector != 0 and a file is supplied.
2241
2242 There is a conflict between the use of aliasing as an alternate email
2243 address, and as a sort of mailing list. If an alias turns the incoming
2244 address into just one address (e.g. J.Caesar->jc44) you may well want to
2245 carry on verifying the generated address to ensure it is valid when
2246 checking incoming mail. If aliasing generates multiple addresses, you
2247 probably don't want to do this. Exim therefore treats the generation of
2248 just a single new address as a special case, and continues on to verify the
2249 generated address. */
2250
2251 if ( !full_info /* Stop if short info wanted AND */
2252 && ( ( !addr_new /* No new address OR */
2253 || addr_new->next /* More than one new address OR */
2254 || testflag(addr_new, af_pfr) /* New address is pfr */
2255 )
2256 || /* OR */
2257 ( addr_new /* At least one new address AND */
2258 && success_on_redirect /* success_on_redirect is set */
2259 ) )
2260 )
2261 {
2262 if (f) fprintf(f, "%s %s\n",
2263 address, address_test_mode ? "is deliverable" : "verified");
2264
2265 /* If we have carried on to verify a child address, we want the value
2266 of $address_data to be that of the child */
2267
2268 vaddr->prop.address_data = addr->prop.address_data;
2269 yield = OK;
2270 goto out;
2271 }
2272 }
2273 } /* Loop for generated addresses */
2274
2275 /* Display the full results of the successful routing, including any generated
2276 addresses. Control gets here only when full_info is set, which requires f not
2277 to be NULL, and this occurs only when a top-level verify is called with the
2278 debugging switch on.
2279
2280 If there are no local and no remote addresses, and there were no pipes, files,
2281 or autoreplies, and there were no errors or deferments, the message is to be
2282 discarded, usually because of the use of :blackhole: in an alias file. */
2283
2284 if (allok && !addr_local && !addr_remote)
2285 {
2286 fprintf(f, "mail to %s is discarded\n", address);
2287 goto out;
2288 }
2289
2290 for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++)
2291 while (addr_list)
2292 {
2293 address_item *addr = addr_list;
2294 address_item *p = addr->parent;
2295 transport_instance * tp = addr->transport;
2296
2297 addr_list = addr->next;
2298
2299 fprintf(f, "%s", CS addr->address);
2300 #ifdef EXPERIMENTAL_SRS
2301 if(addr->prop.srs_sender)
2302 fprintf(f, " [srs = %s]", addr->prop.srs_sender);
2303 #endif
2304
2305 /* If the address is a duplicate, show something about it. */
2306
2307 if (!testflag(addr, af_pfr))
2308 {
2309 tree_node *tnode;
2310 if ((tnode = tree_search(tree_duplicates, addr->unique)))
2311 fprintf(f, " [duplicate, would not be delivered]");
2312 else tree_add_duplicate(addr->unique, addr);
2313 }
2314
2315 /* Now show its parents */
2316
2317 for (p = addr->parent; p; p = p->parent)
2318 fprintf(f, "\n <-- %s", p->address);
2319 fprintf(f, "\n ");
2320
2321 /* Show router, and transport */
2322
2323 fprintf(f, "router = %s, transport = %s\n",
2324 addr->router->name, tp ? tp->name : US"unset");
2325
2326 /* Show any hosts that are set up by a router unless the transport
2327 is going to override them; fiddle a bit to get a nice format. */
2328
2329 if (addr->host_list && tp && !tp->overrides_hosts)
2330 {
2331 host_item *h;
2332 int maxlen = 0;
2333 int maxaddlen = 0;
2334 for (h = addr->host_list; h; h = h->next)
2335 { /* get max lengths of host names, addrs */
2336 int len = Ustrlen(h->name);
2337 if (len > maxlen) maxlen = len;
2338 len = h->address ? Ustrlen(h->address) : 7;
2339 if (len > maxaddlen) maxaddlen = len;
2340 }
2341 for (h = addr->host_list; h; h = h->next)
2342 {
2343 fprintf(f, " host %-*s ", maxlen, h->name);
2344
2345 if (h->address)
2346 fprintf(f, "[%s%-*c", h->address, maxaddlen+1 - Ustrlen(h->address), ']');
2347 else if (tp->info->local)
2348 fprintf(f, " %-*s ", maxaddlen, ""); /* Omit [unknown] for local */
2349 else
2350 fprintf(f, "[%s%-*c", "unknown", maxaddlen+1 - 7, ']');
2351
2352 if (h->mx >= 0) fprintf(f, " MX=%d", h->mx);
2353 if (h->port != PORT_NONE) fprintf(f, " port=%d", h->port);
2354 if (running_in_test_harness && h->dnssec == DS_YES) fputs(" AD", f);
2355 if (h->status == hstatus_unusable) fputs(" ** unusable **", f);
2356 fputc('\n', f);
2357 }
2358 }
2359 }
2360
2361 /* Yield will be DEFER or FAIL if any one address has, only for full_info (which is
2362 the -bv or -bt case). */
2363
2364 out:
2365 verify_mode = NULL;
2366 tls_modify_variables(&tls_in);
2367
2368 return yield;
2369 }
2370
2371
2372
2373
2374 /*************************************************
2375 * Check headers for syntax errors *
2376 *************************************************/
2377
2378 /* This function checks those header lines that contain addresses, and verifies
2379 that all the addresses therein are syntactially correct.
2380
2381 Arguments:
2382 msgptr where to put an error message
2383
2384 Returns: OK
2385 FAIL
2386 */
2387
2388 int
2389 verify_check_headers(uschar **msgptr)
2390 {
2391 header_line *h;
2392 uschar *colon, *s;
2393 int yield = OK;
2394
2395 for (h = header_list; h != NULL && yield == OK; h = h->next)
2396 {
2397 if (h->type != htype_from &&
2398 h->type != htype_reply_to &&
2399 h->type != htype_sender &&
2400 h->type != htype_to &&
2401 h->type != htype_cc &&
2402 h->type != htype_bcc)
2403 continue;
2404
2405 colon = Ustrchr(h->text, ':');
2406 s = colon + 1;
2407 while (isspace(*s)) s++;
2408
2409 /* Loop for multiple addresses in the header, enabling group syntax. Note
2410 that we have to reset this after the header has been scanned. */
2411
2412 parse_allow_group = TRUE;
2413
2414 while (*s != 0)
2415 {
2416 uschar *ss = parse_find_address_end(s, FALSE);
2417 uschar *recipient, *errmess;
2418 int terminator = *ss;
2419 int start, end, domain;
2420
2421 /* Temporarily terminate the string at this point, and extract the
2422 operative address within, allowing group syntax. */
2423
2424 *ss = 0;
2425 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2426 *ss = terminator;
2427
2428 /* Permit an unqualified address only if the message is local, or if the
2429 sending host is configured to be permitted to send them. */
2430
2431 if (recipient != NULL && domain == 0)
2432 {
2433 if (h->type == htype_from || h->type == htype_sender)
2434 {
2435 if (!allow_unqualified_sender) recipient = NULL;
2436 }
2437 else
2438 {
2439 if (!allow_unqualified_recipient) recipient = NULL;
2440 }
2441 if (recipient == NULL) errmess = US"unqualified address not permitted";
2442 }
2443
2444 /* It's an error if no address could be extracted, except for the special
2445 case of an empty address. */
2446
2447 if (recipient == NULL && Ustrcmp(errmess, "empty address") != 0)
2448 {
2449 uschar *verb = US"is";
2450 uschar *t = ss;
2451 uschar *tt = colon;
2452 int len;
2453
2454 /* Arrange not to include any white space at the end in the
2455 error message or the header name. */
2456
2457 while (t > s && isspace(t[-1])) t--;
2458 while (tt > h->text && isspace(tt[-1])) tt--;
2459
2460 /* Add the address that failed to the error message, since in a
2461 header with very many addresses it is sometimes hard to spot
2462 which one is at fault. However, limit the amount of address to
2463 quote - cases have been seen where, for example, a missing double
2464 quote in a humungous To: header creates an "address" that is longer
2465 than string_sprintf can handle. */
2466
2467 len = t - s;
2468 if (len > 1024)
2469 {
2470 len = 1024;
2471 verb = US"begins";
2472 }
2473
2474 /* deconst cast ok as we're passing a non-const to string_printing() */
2475 *msgptr = US string_printing(
2476 string_sprintf("%s: failing address in \"%.*s:\" header %s: %.*s",
2477 errmess, tt - h->text, h->text, verb, len, s));
2478
2479 yield = FAIL;
2480 break; /* Out of address loop */
2481 }
2482
2483 /* Advance to the next address */
2484
2485 s = ss + (terminator? 1:0);
2486 while (isspace(*s)) s++;
2487 } /* Next address */
2488
2489 parse_allow_group = FALSE;
2490 parse_found_group = FALSE;
2491 } /* Next header unless yield has been set FALSE */
2492
2493 return yield;
2494 }
2495
2496
2497 /*************************************************
2498 * Check header names for 8-bit characters *
2499 *************************************************/
2500
2501 /* This function checks for invalid charcters in header names. See
2502 RFC 5322, 2.2. and RFC 6532, 3.
2503
2504 Arguments:
2505 msgptr where to put an error message
2506
2507 Returns: OK
2508 FAIL
2509 */
2510
2511 int
2512 verify_check_header_names_ascii(uschar **msgptr)
2513 {
2514 header_line *h;
2515 uschar *colon, *s;
2516
2517 for (h = header_list; h != NULL; h = h->next)
2518 {
2519 colon = Ustrchr(h->text, ':');
2520 for(s = h->text; s < colon; s++)
2521 {
2522 if ((*s < 33) || (*s > 126))
2523 {
2524 *msgptr = string_sprintf("Invalid character in header \"%.*s\" found",
2525 colon - h->text, h->text);
2526 return FAIL;
2527 }
2528 }
2529 }
2530 return OK;
2531 }
2532
2533 /*************************************************
2534 * Check for blind recipients *
2535 *************************************************/
2536
2537 /* This function checks that every (envelope) recipient is mentioned in either
2538 the To: or Cc: header lines, thus detecting blind carbon copies.
2539
2540 There are two ways of scanning that could be used: either scan the header lines
2541 and tick off the recipients, or scan the recipients and check the header lines.
2542 The original proposed patch did the former, but I have chosen to do the latter,
2543 because (a) it requires no memory and (b) will use fewer resources when there
2544 are many addresses in To: and/or Cc: and only one or two envelope recipients.
2545
2546 Arguments: none
2547 Returns: OK if there are no blind recipients
2548 FAIL if there is at least one blind recipient
2549 */
2550
2551 int
2552 verify_check_notblind(void)
2553 {
2554 int i;
2555 for (i = 0; i < recipients_count; i++)
2556 {
2557 header_line *h;
2558 BOOL found = FALSE;
2559 uschar *address = recipients_list[i].address;
2560
2561 for (h = header_list; !found && h != NULL; h = h->next)
2562 {
2563 uschar *colon, *s;
2564
2565 if (h->type != htype_to && h->type != htype_cc) continue;
2566
2567 colon = Ustrchr(h->text, ':');
2568 s = colon + 1;
2569 while (isspace(*s)) s++;
2570
2571 /* Loop for multiple addresses in the header, enabling group syntax. Note
2572 that we have to reset this after the header has been scanned. */
2573
2574 parse_allow_group = TRUE;
2575
2576 while (*s != 0)
2577 {
2578 uschar *ss = parse_find_address_end(s, FALSE);
2579 uschar *recipient,*errmess;
2580 int terminator = *ss;
2581 int start, end, domain;
2582
2583 /* Temporarily terminate the string at this point, and extract the
2584 operative address within, allowing group syntax. */
2585
2586 *ss = 0;
2587 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2588 *ss = terminator;
2589
2590 /* If we found a valid recipient that has a domain, compare it with the
2591 envelope recipient. Local parts are compared case-sensitively, domains
2592 case-insensitively. By comparing from the start with length "domain", we
2593 include the "@" at the end, which ensures that we are comparing the whole
2594 local part of each address. */
2595
2596 if (recipient != NULL && domain != 0)
2597 {
2598 found = Ustrncmp(recipient, address, domain) == 0 &&
2599 strcmpic(recipient + domain, address + domain) == 0;
2600 if (found) break;
2601 }
2602
2603 /* Advance to the next address */
2604
2605 s = ss + (terminator? 1:0);
2606 while (isspace(*s)) s++;
2607 } /* Next address */
2608
2609 parse_allow_group = FALSE;
2610 parse_found_group = FALSE;
2611 } /* Next header (if found is false) */
2612
2613 if (!found) return FAIL;
2614 } /* Next recipient */
2615
2616 return OK;
2617 }
2618
2619
2620
2621 /*************************************************
2622 * Find if verified sender *
2623 *************************************************/
2624
2625 /* Usually, just a single address is verified as the sender of the message.
2626 However, Exim can be made to verify other addresses as well (often related in
2627 some way), and this is useful in some environments. There may therefore be a
2628 chain of such addresses that have previously been tested. This function finds
2629 whether a given address is on the chain.
2630
2631 Arguments: the address to be verified
2632 Returns: pointer to an address item, or NULL
2633 */
2634
2635 address_item *
2636 verify_checked_sender(uschar *sender)
2637 {
2638 address_item *addr;
2639 for (addr = sender_verified_list; addr != NULL; addr = addr->next)
2640 if (Ustrcmp(sender, addr->address) == 0) break;
2641 return addr;
2642 }
2643
2644
2645
2646
2647
2648 /*************************************************
2649 * Get valid header address *
2650 *************************************************/
2651
2652 /* Scan the originator headers of the message, looking for an address that
2653 verifies successfully. RFC 822 says:
2654
2655 o The "Sender" field mailbox should be sent notices of
2656 any problems in transport or delivery of the original
2657 messages. If there is no "Sender" field, then the
2658 "From" field mailbox should be used.
2659
2660 o If the "Reply-To" field exists, then the reply should
2661 go to the addresses indicated in that field and not to
2662 the address(es) indicated in the "From" field.
2663
2664 So we check a Sender field if there is one, else a Reply_to field, else a From
2665 field. As some strange messages may have more than one of these fields,
2666 especially if they are resent- fields, check all of them if there is more than
2667 one.
2668
2669 Arguments:
2670 user_msgptr points to where to put a user error message
2671 log_msgptr points to where to put a log error message
2672 callout timeout for callout check (passed to verify_address())
2673 callout_overall overall callout timeout (ditto)
2674 callout_connect connect callout timeout (ditto)
2675 se_mailfrom mailfrom for verify; NULL => ""
2676 pm_mailfrom sender for pm callout check (passed to verify_address())
2677 options callout options (passed to verify_address())
2678 verrno where to put the address basic_errno
2679
2680 If log_msgptr is set to something without setting user_msgptr, the caller
2681 normally uses log_msgptr for both things.
2682
2683 Returns: result of the verification attempt: OK, FAIL, or DEFER;
2684 FAIL is given if no appropriate headers are found
2685 */
2686
2687 int
2688 verify_check_header_address(uschar **user_msgptr, uschar **log_msgptr,
2689 int callout, int callout_overall, int callout_connect, uschar *se_mailfrom,
2690 uschar *pm_mailfrom, int options, int *verrno)
2691 {
2692 static int header_types[] = { htype_sender, htype_reply_to, htype_from };
2693 BOOL done = FALSE;
2694 int yield = FAIL;
2695 int i;
2696
2697 for (i = 0; i < 3 && !done; i++)
2698 {
2699 header_line *h;
2700 for (h = header_list; h != NULL && !done; h = h->next)
2701 {
2702 int terminator, new_ok;
2703 uschar *s, *ss, *endname;
2704
2705 if (h->type != header_types[i]) continue;
2706 s = endname = Ustrchr(h->text, ':') + 1;
2707
2708 /* Scan the addresses in the header, enabling group syntax. Note that we
2709 have to reset this after the header has been scanned. */
2710
2711 parse_allow_group = TRUE;
2712
2713 while (*s != 0)
2714 {
2715 address_item *vaddr;
2716
2717 while (isspace(*s) || *s == ',') s++;
2718 if (*s == 0) break; /* End of header */
2719
2720 ss = parse_find_address_end(s, FALSE);
2721
2722 /* The terminator is a comma or end of header, but there may be white
2723 space preceding it (including newline for the last address). Move back
2724 past any white space so we can check against any cached envelope sender
2725 address verifications. */
2726
2727 while (isspace(ss[-1])) ss--;
2728 terminator = *ss;
2729 *ss = 0;
2730
2731 HDEBUG(D_verify) debug_printf("verifying %.*s header address %s\n",
2732 (int)(endname - h->text), h->text, s);
2733
2734 /* See if we have already verified this address as an envelope sender,
2735 and if so, use the previous answer. */
2736
2737 vaddr = verify_checked_sender(s);
2738
2739 if (vaddr != NULL && /* Previously checked */
2740 (callout <= 0 || /* No callout needed; OR */
2741 vaddr->special_action > 256)) /* Callout was done */
2742 {
2743 new_ok = vaddr->special_action & 255;
2744 HDEBUG(D_verify) debug_printf("previously checked as envelope sender\n");
2745 *ss = terminator; /* Restore shortened string */
2746 }
2747
2748 /* Otherwise we run the verification now. We must restore the shortened
2749 string before running the verification, so the headers are correct, in
2750 case there is any rewriting. */
2751
2752 else
2753 {
2754 int start, end, domain;
2755 uschar *address = parse_extract_address(s, log_msgptr, &start, &end,
2756 &domain, FALSE);
2757
2758 *ss = terminator;
2759
2760 /* If we found an empty address, just carry on with the next one, but
2761 kill the message. */
2762
2763 if (address == NULL && Ustrcmp(*log_msgptr, "empty address") == 0)
2764 {
2765 *log_msgptr = NULL;
2766 s = ss;
2767 continue;
2768 }
2769
2770 /* If verification failed because of a syntax error, fail this
2771 function, and ensure that the failing address gets added to the error
2772 message. */
2773
2774 if (address == NULL)
2775 {
2776 new_ok = FAIL;
2777 while (ss > s && isspace(ss[-1])) ss--;
2778 *log_msgptr = string_sprintf("syntax error in '%.*s' header when "
2779 "scanning for sender: %s in \"%.*s\"",
2780 endname - h->text, h->text, *log_msgptr, ss - s, s);
2781 yield = FAIL;
2782 done = TRUE;
2783 break;
2784 }
2785
2786 /* Else go ahead with the sender verification. But it isn't *the*
2787 sender of the message, so set vopt_fake_sender to stop sender_address
2788 being replaced after rewriting or qualification. */
2789
2790 else
2791 {
2792 vaddr = deliver_make_addr(address, FALSE);
2793 new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender,
2794 callout, callout_overall, callout_connect, se_mailfrom,
2795 pm_mailfrom, NULL);
2796 }
2797 }
2798
2799 /* We now have the result, either newly found, or cached. If we are
2800 giving out error details, set a specific user error. This means that the
2801 last of these will be returned to the user if all three fail. We do not
2802 set a log message - the generic one below will be used. */
2803
2804 if (new_ok != OK)
2805 {
2806 *verrno = vaddr->basic_errno;
2807 if (smtp_return_error_details)
2808 {
2809 *user_msgptr = string_sprintf("Rejected after DATA: "
2810 "could not verify \"%.*s\" header address\n%s: %s",
2811 endname - h->text, h->text, vaddr->address, vaddr->message);
2812 }
2813 }
2814
2815 /* Success or defer */
2816
2817 if (new_ok == OK)
2818 {
2819 yield = OK;
2820 done = TRUE;
2821 break;
2822 }
2823
2824 if (new_ok == DEFER) yield = DEFER;
2825
2826 /* Move on to any more addresses in the header */
2827
2828 s = ss;
2829 } /* Next address */
2830
2831 parse_allow_group = FALSE;
2832 parse_found_group = FALSE;
2833 } /* Next header, unless done */
2834 } /* Next header type unless done */
2835
2836 if (yield == FAIL && *log_msgptr == NULL)
2837 *log_msgptr = US"there is no valid sender in any header line";
2838
2839 if (yield == DEFER && *log_msgptr == NULL)
2840 *log_msgptr = US"all attempts to verify a sender in a header line deferred";
2841
2842 return yield;
2843 }
2844
2845
2846
2847
2848 /*************************************************
2849 * Get RFC 1413 identification *
2850 *************************************************/
2851
2852 /* Attempt to get an id from the sending machine via the RFC 1413 protocol. If
2853 the timeout is set to zero, then the query is not done. There may also be lists
2854 of hosts and nets which are exempt. To guard against malefactors sending
2855 non-printing characters which could, for example, disrupt a message's headers,
2856 make sure the string consists of printing characters only.
2857
2858 Argument:
2859 port the port to connect to; usually this is IDENT_PORT (113), but when
2860 running in the test harness with -bh a different value is used.
2861
2862 Returns: nothing
2863
2864 Side effect: any received ident value is put in sender_ident (NULL otherwise)
2865 */
2866
2867 void
2868 verify_get_ident(int port)
2869 {
2870 int sock, host_af, qlen;
2871 int received_sender_port, received_interface_port, n;
2872 uschar *p;
2873 uschar buffer[2048];
2874
2875 /* Default is no ident. Check whether we want to do an ident check for this
2876 host. */
2877
2878 sender_ident = NULL;
2879 if (rfc1413_query_timeout <= 0 || verify_check_host(&rfc1413_hosts) != OK)
2880 return;
2881
2882 DEBUG(D_ident) debug_printf("doing ident callback\n");
2883
2884 /* Set up a connection to the ident port of the remote host. Bind the local end
2885 to the incoming interface address. If the sender host address is an IPv6
2886 address, the incoming interface address will also be IPv6. */
2887
2888 host_af = (Ustrchr(sender_host_address, ':') == NULL)? AF_INET : AF_INET6;
2889 sock = ip_socket(SOCK_STREAM, host_af);
2890 if (sock < 0) return;
2891
2892 if (ip_bind(sock, host_af, interface_address, 0) < 0)
2893 {
2894 DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n",
2895 strerror(errno));
2896 goto END_OFF;
2897 }
2898
2899 if (ip_connect(sock, host_af, sender_host_address, port, rfc1413_query_timeout)
2900 < 0)
2901 {
2902 if (errno == ETIMEDOUT && LOGGING(ident_timeout))
2903 {
2904 log_write(0, LOG_MAIN, "ident connection to %s timed out",
2905 sender_host_address);
2906 }
2907 else
2908 {
2909 DEBUG(D_ident) debug_printf("ident connection to %s failed: %s\n",
2910 sender_host_address, strerror(errno));
2911 }
2912 goto END_OFF;
2913 }
2914
2915 /* Construct and send the query. */
2916
2917 sprintf(CS buffer, "%d , %d\r\n", sender_host_port, interface_port);
2918 qlen = Ustrlen(buffer);
2919 if (send(sock, buffer, qlen, 0) < 0)
2920 {
2921 DEBUG(D_ident) debug_printf("ident send failed: %s\n", strerror(errno));
2922 goto END_OFF;
2923 }
2924
2925 /* Read a response line. We put it into the rest of the buffer, using several
2926 recv() calls if necessary. */
2927
2928 p = buffer + qlen;
2929
2930 for (;;)
2931 {
2932 uschar *pp;
2933 int count;
2934 int size = sizeof(buffer) - (p - buffer);
2935
2936 if (size <= 0) goto END_OFF; /* Buffer filled without seeing \n. */
2937 count = ip_recv(sock, p, size, rfc1413_query_timeout);
2938 if (count <= 0) goto END_OFF; /* Read error or EOF */
2939
2940 /* Scan what we just read, to see if we have reached the terminating \r\n. Be
2941 generous, and accept a plain \n terminator as well. The only illegal
2942 character is 0. */
2943
2944 for (pp = p; pp < p + count; pp++)
2945 {
2946 if (*pp == 0) goto END_OFF; /* Zero octet not allowed */
2947 if (*pp == '\n')
2948 {
2949 if (pp[-1] == '\r') pp--;
2950 *pp = 0;
2951 goto GOT_DATA; /* Break out of both loops */
2952 }
2953 }
2954
2955 /* Reached the end of the data without finding \n. Let the loop continue to
2956 read some more, if there is room. */
2957
2958 p = pp;
2959 }
2960
2961 GOT_DATA:
2962
2963 /* We have received a line of data. Check it carefully. It must start with the
2964 same two port numbers that we sent, followed by data as defined by the RFC. For
2965 example,
2966
2967 12345 , 25 : USERID : UNIX :root
2968
2969 However, the amount of white space may be different to what we sent. In the
2970 "osname" field there may be several sub-fields, comma separated. The data we
2971 actually want to save follows the third colon. Some systems put leading spaces
2972 in it - we discard those. */
2973
2974 if (sscanf(CS buffer + qlen, "%d , %d%n", &received_sender_port,
2975 &received_interface_port, &n) != 2 ||
2976 received_sender_port != sender_host_port ||
2977 received_interface_port != interface_port)
2978 goto END_OFF;
2979
2980 p = buffer + qlen + n;
2981 while(isspace(*p)) p++;
2982 if (*p++ != ':') goto END_OFF;
2983 while(isspace(*p)) p++;
2984 if (Ustrncmp(p, "USERID", 6) != 0) goto END_OFF;
2985 p += 6;
2986 while(isspace(*p)) p++;
2987 if (*p++ != ':') goto END_OFF;
2988 while (*p != 0 && *p != ':') p++;
2989 if (*p++ == 0) goto END_OFF;
2990 while(isspace(*p)) p++;
2991 if (*p == 0) goto END_OFF;
2992
2993 /* The rest of the line is the data we want. We turn it into printing
2994 characters when we save it, so that it cannot mess up the format of any logging
2995 or Received: lines into which it gets inserted. We keep a maximum of 127
2996 characters. The deconst cast is ok as we fed a nonconst to string_printing() */
2997
2998 sender_ident = US string_printing(string_copyn(p, 127));
2999 DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident);
3000
3001 END_OFF:
3002 (void)close(sock);
3003 return;
3004 }
3005
3006
3007
3008
3009 /*************************************************
3010 * Match host to a single host-list item *
3011 *************************************************/
3012
3013 /* This function compares a host (name or address) against a single item
3014 from a host list. The host name gets looked up if it is needed and is not
3015 already known. The function is called from verify_check_this_host() via
3016 match_check_list(), which is why most of its arguments are in a single block.
3017
3018 Arguments:
3019 arg the argument block (see below)
3020 ss the host-list item
3021 valueptr where to pass back looked up data, or NULL
3022 error for error message when returning ERROR
3023
3024 The block contains:
3025 host_name (a) the host name, or
3026 (b) NULL, implying use sender_host_name and
3027 sender_host_aliases, looking them up if required, or
3028 (c) the empty string, meaning that only IP address matches
3029 are permitted
3030 host_address the host address
3031 host_ipv4 the IPv4 address taken from an IPv6 one
3032
3033 Returns: OK matched
3034 FAIL did not match
3035 DEFER lookup deferred
3036 ERROR (a) failed to find the host name or IP address, or
3037 (b) unknown lookup type specified, or
3038 (c) host name encountered when only IP addresses are
3039 being matched
3040 */
3041
3042 int
3043 check_host(void *arg, const uschar *ss, const uschar **valueptr, uschar **error)
3044 {
3045 check_host_block *cb = (check_host_block *)arg;
3046 int mlen = -1;
3047 int maskoffset;
3048 BOOL iplookup = FALSE;
3049 BOOL isquery = FALSE;
3050 BOOL isiponly = cb->host_name != NULL && cb->host_name[0] == 0;
3051 const uschar *t;
3052 uschar *semicolon;
3053 uschar **aliases;
3054
3055 /* Optimize for the special case when the pattern is "*". */
3056
3057 if (*ss == '*' && ss[1] == 0) return OK;
3058
3059 /* If the pattern is empty, it matches only in the case when there is no host -
3060 this can occur in ACL checking for SMTP input using the -bs option. In this
3061 situation, the host address is the empty string. */
3062
3063 if (cb->host_address[0] == 0) return (*ss == 0)? OK : FAIL;
3064 if (*ss == 0) return FAIL;
3065
3066 /* If the pattern is precisely "@" then match against the primary host name,
3067 provided that host name matching is permitted; if it's "@[]" match against the
3068 local host's IP addresses. */
3069
3070 if (*ss == '@')
3071 {
3072 if (ss[1] == 0)
3073 {
3074 if (isiponly) return ERROR;
3075 ss = primary_hostname;
3076 }
3077 else if (Ustrcmp(ss, "@[]") == 0)
3078 {
3079 ip_address_item *ip;
3080 for (ip = host_find_interfaces(); ip != NULL; ip = ip->next)
3081 if (Ustrcmp(ip->address, cb->host_address) == 0) return OK;
3082 return FAIL;
3083 }
3084 }
3085
3086 /* If the pattern is an IP address, optionally followed by a bitmask count, do
3087 a (possibly masked) comparision with the current IP address. */
3088
3089 if (string_is_ip_address(ss, &maskoffset) != 0)
3090 return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL);
3091
3092 /* The pattern is not an IP address. A common error that people make is to omit
3093 one component of an IPv4 address, either by accident, or believing that, for
3094 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,
3095 which it isn't. (Those applications that do accept 1.2.3 as an IP address
3096 interpret it as 1.2.0.3 because the final component becomes 16-bit - this is an
3097 ancient specification.) To aid in debugging these cases, we give a specific
3098 error if the pattern contains only digits and dots or contains a slash preceded
3099 only by digits and dots (a slash at the start indicates a file name and of
3100 course slashes may be present in lookups, but not preceded only by digits and
3101 dots). */
3102
3103 for (t = ss; isdigit(*t) || *t == '.'; t++);
3104 if (*t == 0 || (*t == '/' && t != ss))
3105 {
3106 *error = US"malformed IPv4 address or address mask";
3107 return ERROR;
3108 }
3109
3110 /* See if there is a semicolon in the pattern */
3111
3112 semicolon = Ustrchr(ss, ';');
3113
3114 /* If we are doing an IP address only match, then all lookups must be IP
3115 address lookups, even if there is no "net-". */
3116
3117 if (isiponly)
3118 {
3119 iplookup = semicolon != NULL;
3120 }
3121
3122 /* Otherwise, if the item is of the form net[n]-lookup;<file|query> then it is
3123 a lookup on a masked IP network, in textual form. We obey this code even if we
3124 have already set iplookup, so as to skip over the "net-" prefix and to set the
3125 mask length. The net- stuff really only applies to single-key lookups where the
3126 key is implicit. For query-style lookups the key is specified in the query.
3127 From release 4.30, the use of net- for query style is no longer needed, but we
3128 retain it for backward compatibility. */
3129
3130 if (Ustrncmp(ss, "net", 3) == 0 && semicolon != NULL)
3131 {
3132 mlen = 0;
3133 for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0';
3134 if (mlen == 0 && t == ss+3) mlen = -1; /* No mask supplied */
3135 iplookup = (*t++ == '-');
3136 }
3137 else t = ss;
3138
3139 /* Do the IP address lookup if that is indeed what we have */
3140
3141 if (iplookup)
3142 {
3143 int insize;
3144 int search_type;
3145 int incoming[4];
3146 void *handle;
3147 uschar *filename, *key, *result;
3148 uschar buffer[64];
3149
3150 /* Find the search type */
3151
3152 search_type = search_findtype(t, semicolon - t);
3153
3154 if (search_type < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
3155 search_error_message);
3156
3157 /* Adjust parameters for the type of lookup. For a query-style lookup, there
3158 is no file name, and the "key" is just the query. For query-style with a file
3159 name, we have to fish the file off the start of the query. For a single-key
3160 lookup, the key is the current IP address, masked appropriately, and
3161 reconverted to text form, with the mask appended. For IPv6 addresses, specify
3162 dot separators instead of colons, except when the lookup type is "iplsearch".
3163 */
3164
3165 if (mac_islookup(search_type, lookup_absfilequery))
3166 {
3167 filename = semicolon + 1;
3168 key = filename;
3169 while (*key != 0 && !isspace(*key)) key++;
3170 filename = string_copyn(filename, key - filename);
3171 while (isspace(*key)) key++;
3172 }
3173 else if (mac_islookup(search_type, lookup_querystyle))
3174 {
3175 filename = NULL;
3176 key = semicolon + 1;
3177 }
3178 else /* Single-key style */
3179 {
3180 int sep = (Ustrcmp(lookup_list[search_type]->name, "iplsearch") == 0)?
3181 ':' : '.';
3182 insize = host_aton(cb->host_address, incoming);
3183 host_mask(insize, incoming, mlen);
3184 (void)host_nmtoa(insize, incoming, mlen, buffer, sep);
3185 key = buffer;
3186 filename = semicolon + 1;
3187 }
3188
3189 /* Now do the actual lookup; note that there is no search_close() because
3190 of the caching arrangements. */
3191
3192 if (!(handle = search_open(filename, search_type, 0, NULL, NULL)))
3193 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s", search_error_message);
3194
3195 result = search_find(handle, filename, key, -1, NULL, 0, 0, NULL);
3196 if (valueptr != NULL) *valueptr = result;
3197 return (result != NULL)? OK : search_find_defer? DEFER: FAIL;
3198 }
3199
3200 /* The pattern is not an IP address or network reference of any kind. That is,
3201 it is a host name pattern. If this is an IP only match, there's an error in the
3202 host list. */
3203
3204 if (isiponly)
3205 {
3206 *error = US"cannot match host name in match_ip list";
3207 return ERROR;
3208 }
3209
3210 /* Check the characters of the pattern to see if they comprise only letters,
3211 digits, full stops, and hyphens (the constituents of domain names). Allow
3212 underscores, as they are all too commonly found. Sigh. Also, if
3213 allow_utf8_domains is set, allow top-bit characters. */
3214
3215 for (t = ss; *t != 0; t++)
3216 if (!isalnum(*t) && *t != '.' && *t != '-' && *t != '_' &&
3217 (!allow_utf8_domains || *t < 128)) break;
3218
3219 /* If the pattern is a complete domain name, with no fancy characters, look up
3220 its IP address and match against that. Note that a multi-homed host will add
3221 items to the chain. */
3222
3223 if (*t == 0)
3224 {
3225 int rc;
3226 host_item h;
3227 h.next = NULL;
3228 h.name = ss;
3229 h.address = NULL;
3230 h.mx = MX_NONE;
3231
3232 /* Using byname rather than bydns here means we cannot determine dnssec
3233 status. On the other hand it is unclear how that could be either
3234 propagated up or enforced. */
3235
3236 rc = host_find_byname(&h, NULL, HOST_FIND_QUALIFY_SINGLE, NULL, FALSE);
3237 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3238 {
3239 host_item *hh;
3240 for (hh = &h; hh != NULL; hh = hh->next)
3241 {
3242 if (host_is_in_net(hh->address, cb->host_address, 0)) return OK;
3243 }
3244 return FAIL;
3245 }
3246 if (rc == HOST_FIND_AGAIN) return DEFER;
3247 *error = string_sprintf("failed to find IP address for %s", ss);
3248 return ERROR;
3249 }
3250
3251 /* Almost all subsequent comparisons require the host name, and can be done
3252 using the general string matching function. When this function is called for
3253 outgoing hosts, the name is always given explicitly. If it is NULL, it means we
3254 must use sender_host_name and its aliases, looking them up if necessary. */
3255
3256 if (cb->host_name != NULL) /* Explicit host name given */
3257 return match_check_string(cb->host_name, ss, -1, TRUE, TRUE, TRUE,
3258 valueptr);
3259
3260 /* Host name not given; in principle we need the sender host name and its
3261 aliases. However, for query-style lookups, we do not need the name if the
3262 query does not contain $sender_host_name. From release 4.23, a reference to
3263 $sender_host_name causes it to be looked up, so we don't need to do the lookup
3264 on spec. */
3265
3266 if ((semicolon = Ustrchr(ss, ';')) != NULL)
3267 {
3268 const uschar *affix;
3269 int partial, affixlen, starflags, id;
3270
3271 *semicolon = 0;
3272 id = search_findtype_partial(ss, &partial, &affix, &affixlen, &starflags);
3273 *semicolon=';';
3274
3275 if (id < 0) /* Unknown lookup type */
3276 {
3277 log_write(0, LOG_MAIN|LOG_PANIC, "%s in host list item \"%s\"",
3278 search_error_message, ss);
3279 return DEFER;
3280 }
3281 isquery = mac_islookup(id, lookup_querystyle|lookup_absfilequery);
3282 }
3283
3284 if (isquery)
3285 {
3286 switch(match_check_string(US"", ss, -1, TRUE, TRUE, TRUE, valueptr))
3287 {
3288 case OK: return OK;
3289 case DEFER: return DEFER;
3290 default: return FAIL;
3291 }
3292 }
3293
3294 /* Not a query-style lookup; must ensure the host name is present, and then we
3295 do a check on the name and all its aliases. */
3296
3297 if (sender_host_name == NULL)
3298 {
3299 HDEBUG(D_host_lookup)
3300 debug_printf("sender host name required, to match against %s\n", ss);
3301 if (host_lookup_failed || host_name_lookup() != OK)
3302 {
3303 *error = string_sprintf("failed to find host name for %s",
3304 sender_host_address);;
3305 return ERROR;
3306 }
3307 host_build_sender_fullhost();
3308 }
3309
3310 /* Match on the sender host name, using the general matching function */
3311
3312 switch(match_check_string(sender_host_name, ss, -1, TRUE, TRUE, TRUE,
3313 valueptr))
3314 {
3315 case OK: return OK;
3316 case DEFER: return DEFER;
3317 }
3318
3319 /* If there are aliases, try matching on them. */
3320
3321 aliases = sender_host_aliases;
3322 while (*aliases != NULL)
3323 {
3324 switch(match_check_string(*aliases++, ss, -1, TRUE, TRUE, TRUE, valueptr))
3325 {
3326 case OK: return OK;
3327 case DEFER: return DEFER;
3328 }
3329 }
3330 return FAIL;
3331 }
3332
3333
3334
3335
3336 /*************************************************
3337 * Check a specific host matches a host list *
3338 *************************************************/
3339
3340 /* This function is passed a host list containing items in a number of
3341 different formats and the identity of a host. Its job is to determine whether
3342 the given host is in the set of hosts defined by the list. The host name is
3343 passed as a pointer so that it can be looked up if needed and not already
3344 known. This is commonly the case when called from verify_check_host() to check
3345 an incoming connection. When called from elsewhere the host name should usually
3346 be set.
3347
3348 This function is now just a front end to match_check_list(), which runs common
3349 code for scanning a list. We pass it the check_host() function to perform a
3350 single test.
3351
3352 Arguments:
3353 listptr pointer to the host list
3354 cache_bits pointer to cache for named lists, or NULL
3355 host_name the host name or NULL, implying use sender_host_name and
3356 sender_host_aliases, looking them up if required
3357 host_address the IP address
3358 valueptr if not NULL, data from a lookup is passed back here
3359
3360 Returns: OK if the host is in the defined set
3361 FAIL if the host is not in the defined set,
3362 DEFER if a data lookup deferred (not a host lookup)
3363
3364 If the host name was needed in order to make a comparison, and could not be
3365 determined from the IP address, the result is FAIL unless the item
3366 "+allow_unknown" was met earlier in the list, in which case OK is returned. */
3367
3368 int
3369 verify_check_this_host(const uschar **listptr, unsigned int *cache_bits,
3370 const uschar *host_name, const uschar *host_address, const uschar **valueptr)
3371 {
3372 int rc;
3373 unsigned int *local_cache_bits = cache_bits;
3374 const uschar *save_host_address = deliver_host_address;
3375 check_host_block cb;
3376 cb.host_name = host_name;
3377 cb.host_address = host_address;
3378
3379 if (valueptr != NULL) *valueptr = NULL;
3380
3381 /* If the host address starts off ::ffff: it is an IPv6 address in
3382 IPv4-compatible mode. Find the IPv4 part for checking against IPv4
3383 addresses. */
3384
3385 cb.host_ipv4 = (Ustrncmp(host_address, "::ffff:", 7) == 0)?
3386 host_address + 7 : host_address;
3387
3388 /* During the running of the check, put the IP address into $host_address. In
3389 the case of calls from the smtp transport, it will already be there. However,
3390 in other calls (e.g. when testing ignore_target_hosts), it won't. Just to be on
3391 the safe side, any existing setting is preserved, though as I write this
3392 (November 2004) I can't see any cases where it is actually needed. */
3393
3394 deliver_host_address = host_address;
3395 rc = match_check_list(
3396 listptr, /* the list */
3397 0, /* separator character */
3398 &hostlist_anchor, /* anchor pointer */
3399 &local_cache_bits, /* cache pointer */
3400 check_host, /* function for testing */
3401 &cb, /* argument for function */
3402 MCL_HOST, /* type of check */
3403 (host_address == sender_host_address)?
3404 US"host" : host_address, /* text for debugging */
3405 valueptr); /* where to pass back data */
3406 deliver_host_address = save_host_address;
3407 return rc;
3408 }
3409
3410
3411
3412
3413 /*************************************************
3414 * Check the given host item matches a list *
3415 *************************************************/
3416 int
3417 verify_check_given_host(uschar **listptr, host_item *host)
3418 {
3419 return verify_check_this_host(CUSS listptr, NULL, host->name, host->address, NULL);
3420 }
3421
3422 /*************************************************
3423 * Check the remote host matches a list *
3424 *************************************************/
3425
3426 /* This is a front end to verify_check_this_host(), created because checking
3427 the remote host is a common occurrence. With luck, a good compiler will spot
3428 the tail recursion and optimize it. If there's no host address, this is
3429 command-line SMTP input - check against an empty string for the address.
3430
3431 Arguments:
3432 listptr pointer to the host list
3433
3434 Returns: the yield of verify_check_this_host(),
3435 i.e. OK, FAIL, or DEFER
3436 */
3437
3438 int
3439 verify_check_host(uschar **listptr)
3440 {
3441 return verify_check_this_host(CUSS listptr, sender_host_cache, NULL,
3442 (sender_host_address == NULL)? US"" : sender_host_address, NULL);
3443 }
3444
3445
3446
3447
3448
3449 /*************************************************
3450 * Invert an IP address *
3451 *************************************************/
3452
3453 /* Originally just used for DNS xBL lists, now also used for the
3454 reverse_ip expansion operator.
3455
3456 Arguments:
3457 buffer where to put the answer
3458 address the address to invert
3459 */
3460
3461 void
3462 invert_address(uschar *buffer, uschar *address)
3463 {
3464 int bin[4];
3465 uschar *bptr = buffer;
3466
3467 /* If this is an IPv4 address mapped into IPv6 format, adjust the pointer
3468 to the IPv4 part only. */
3469
3470 if (Ustrncmp(address, "::ffff:", 7) == 0) address += 7;
3471
3472 /* Handle IPv4 address: when HAVE_IPV6 is false, the result of host_aton() is
3473 always 1. */
3474
3475 if (host_aton(address, bin) == 1)
3476 {
3477 int i;
3478 int x = bin[0];
3479 for (i = 0; i < 4; i++)
3480 {
3481 sprintf(CS bptr, "%d.", x & 255);
3482 while (*bptr) bptr++;
3483 x >>= 8;
3484 }
3485 }
3486
3487 /* Handle IPv6 address. Actually, as far as I know, there are no IPv6 addresses
3488 in any DNS black lists, and the format in which they will be looked up is
3489 unknown. This is just a guess. */
3490
3491 #if HAVE_IPV6
3492 else
3493 {
3494 int i, j;
3495 for (j = 3; j >= 0; j--)
3496 {
3497 int x = bin[j];
3498 for (i = 0; i < 8; i++)
3499 {
3500 sprintf(CS bptr, "%x.", x & 15);
3501 while (*bptr) bptr++;
3502 x >>= 4;
3503 }
3504 }
3505 }
3506 #endif
3507
3508 /* Remove trailing period -- this is needed so that both arbitrary
3509 dnsbl keydomains and inverted addresses may be combined with the
3510 same format string, "%s.%s" */
3511
3512 *(--bptr) = 0;
3513 }
3514
3515
3516
3517 /*************************************************
3518 * Perform a single dnsbl lookup *
3519 *************************************************/
3520
3521 /* This function is called from verify_check_dnsbl() below. It is also called
3522 recursively from within itself when domain and domain_txt are different
3523 pointers, in order to get the TXT record from the alternate domain.
3524
3525 Arguments:
3526 domain the outer dnsbl domain
3527 domain_txt alternate domain to lookup TXT record on success; when the
3528 same domain is to be used, domain_txt == domain (that is,
3529 the pointers must be identical, not just the text)
3530 keydomain the current keydomain (for debug message)
3531 prepend subdomain to lookup (like keydomain, but
3532 reversed if IP address)
3533 iplist the list of matching IP addresses, or NULL for "any"
3534 bitmask true if bitmask matching is wanted
3535 match_type condition for 'succeed' result
3536 0 => Any RR in iplist (=)
3537 1 => No RR in iplist (!=)
3538 2 => All RRs in iplist (==)
3539 3 => Some RRs not in iplist (!==)
3540 the two bits are defined as MT_NOT and MT_ALL
3541 defer_return what to return for a defer
3542
3543 Returns: OK if lookup succeeded
3544 FAIL if not
3545 */
3546
3547 static int
3548 one_check_dnsbl(uschar *domain, uschar *domain_txt, uschar *keydomain,
3549 uschar *prepend, uschar *iplist, BOOL bitmask, int match_type,
3550 int defer_return)
3551 {
3552 dns_answer dnsa;
3553 dns_scan dnss;
3554 tree_node *t;
3555 dnsbl_cache_block *cb;
3556 int old_pool = store_pool;
3557 uschar query[256]; /* DNS domain max length */
3558
3559 /* Construct the specific query domainname */
3560
3561 if (!string_format(query, sizeof(query), "%s.%s", prepend, domain))
3562 {
3563 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
3564 "(ignored): %s...", query);
3565 return FAIL;
3566 }
3567
3568 /* Look for this query in the cache. */
3569
3570 if ( (t = tree_search(dnsbl_cache, query))
3571 && (cb = t->data.ptr)->expiry > time(NULL)
3572 )
3573
3574 /* Previous lookup was cached */
3575
3576 {
3577 HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
3578 }
3579
3580 /* If not cached from a previous lookup, we must do a DNS lookup, and
3581 cache the result in permanent memory. */
3582
3583 else
3584 {
3585 uint ttl = 3600;
3586
3587 store_pool = POOL_PERM;
3588
3589 if (t)
3590 {
3591 HDEBUG(D_dnsbl) debug_printf("cached data found but past valid time; ");
3592 }
3593
3594 else
3595 { /* Set up a tree entry to cache the lookup */
3596 t = store_get(sizeof(tree_node) + Ustrlen(query));
3597 Ustrcpy(t->name, query);
3598 t->data.ptr = cb = store_get(sizeof(dnsbl_cache_block));
3599 (void)tree_insertnode(&dnsbl_cache, t);
3600 }
3601
3602 /* Do the DNS loopup . */
3603
3604 HDEBUG(D_dnsbl) debug_printf("new DNS lookup for %s\n", query);
3605 cb->rc = dns_basic_lookup(&dnsa, query, T_A);
3606 cb->text_set = FALSE;
3607 cb->text = NULL;
3608 cb->rhs = NULL;
3609
3610 /* If the lookup succeeded, cache the RHS address. The code allows for
3611 more than one address - this was for complete generality and the possible
3612 use of A6 records. However, A6 records have been reduced to experimental
3613 status (August 2001) and may die out. So they may never get used at all,
3614 let alone in dnsbl records. However, leave the code here, just in case.
3615
3616 Quite apart from one A6 RR generating multiple addresses, there are DNS
3617 lists that return more than one A record, so we must handle multiple
3618 addresses generated in that way as well.
3619
3620 Mark the cache entry with the "now" plus the minimum of the address TTLs,
3621 or some suitably far-future time if none were found. */
3622
3623 if (cb->rc == DNS_SUCCEED)
3624 {
3625 dns_record *rr;
3626 dns_address **addrp = &(cb->rhs);
3627 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
3628 rr;
3629 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3630 {
3631 if (rr->type == T_A)
3632 {
3633 dns_address *da = dns_address_from_rr(&dnsa, rr);
3634 if (da)
3635 {
3636 *addrp = da;
3637 while (da->next != NULL) da = da->next;
3638 addrp = &(da->next);
3639 if (ttl > rr->ttl) ttl = rr->ttl;
3640 }
3641 }
3642 }
3643
3644 /* If we didn't find any A records, change the return code. This can
3645 happen when there is a CNAME record but there are no A records for what
3646 it points to. */
3647
3648 if (cb->rhs == NULL) cb->rc = DNS_NODATA;
3649 }
3650
3651 cb->expiry = time(NULL)+ttl;
3652 store_pool = old_pool;
3653 }
3654
3655 /* We now have the result of the DNS lookup, either newly done, or cached
3656 from a previous call. If the lookup succeeded, check against the address
3657 list if there is one. This may be a positive equality list (introduced by
3658 "="), a negative equality list (introduced by "!="), a positive bitmask
3659 list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/
3660
3661 if (cb->rc == DNS_SUCCEED)
3662 {
3663 dns_address *da = NULL;
3664 uschar *addlist = cb->rhs->address;
3665
3666 /* For A and AAAA records, there may be multiple addresses from multiple
3667 records. For A6 records (currently not expected to be used) there may be
3668 multiple addresses from a single record. */
3669
3670 for (da = cb->rhs->next; da != NULL; da = da->next)
3671 addlist = string_sprintf("%s, %s", addlist, da->address);
3672
3673 HDEBUG(D_dnsbl) debug_printf("DNS lookup for %s succeeded (yielding %s)\n",
3674 query, addlist);
3675
3676 /* Address list check; this can be either for equality, or via a bitmask.
3677 In the latter case, all the bits must match. */
3678
3679 if (iplist != NULL)
3680 {
3681 for (da = cb->rhs; da != NULL; da = da->next)
3682 {
3683 int ipsep = ',';
3684 uschar ip[46];
3685 const uschar *ptr = iplist;
3686 uschar *res;
3687
3688 /* Handle exact matching */
3689
3690 if (!bitmask)
3691 {
3692 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))) != NULL)
3693 {
3694 if (Ustrcmp(CS da->address, ip) == 0) break;
3695 }
3696 }
3697
3698 /* Handle bitmask matching */
3699
3700 else
3701 {
3702 int address[4];
3703 int mask = 0;
3704
3705 /* At present, all known DNS blocking lists use A records, with
3706 IPv4 addresses on the RHS encoding the information they return. I
3707 wonder if this will linger on as the last vestige of IPv4 when IPv6
3708 is ubiquitous? Anyway, for now we use paranoia code to completely
3709 ignore IPv6 addresses. The default mask is 0, which always matches.
3710 We change this only for IPv4 addresses in the list. */
3711
3712 if (host_aton(da->address, address) == 1) mask = address[0];
3713
3714 /* Scan the returned addresses, skipping any that are IPv6 */
3715
3716 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))) != NULL)
3717 {
3718 if (host_aton(ip, address) != 1) continue;
3719 if ((address[0] & mask) == address[0]) break;
3720 }
3721 }
3722
3723 /* If either
3724
3725 (a) An IP address in an any ('=') list matched, or
3726 (b) No IP address in an all ('==') list matched
3727
3728 then we're done searching. */
3729
3730 if (((match_type & MT_ALL) != 0) == (res == NULL)) break;
3731 }
3732
3733 /* If da == NULL, either
3734
3735 (a) No IP address in an any ('=') list matched, or
3736 (b) An IP address in an all ('==') list didn't match
3737
3738 so behave as if the DNSBL lookup had not succeeded, i.e. the host is not on
3739 the list. */
3740
3741 if ((match_type == MT_NOT || match_type == MT_ALL) != (da == NULL))
3742 {
3743 HDEBUG(D_dnsbl)
3744 {
3745 uschar *res = NULL;
3746 switch(match_type)
3747 {
3748 case 0:
3749 res = US"was no match";
3750 break;
3751 case MT_NOT:
3752 res = US"was an exclude match";
3753 break;
3754 case MT_ALL:
3755 res = US"was an IP address that did not match";
3756 break;
3757 case MT_NOT|MT_ALL:
3758 res = US"were no IP addresses that did not match";
3759 break;
3760 }
3761 debug_printf("=> but we are not accepting this block class because\n");
3762 debug_printf("=> there %s for %s%c%s\n",
3763 res,
3764 ((match_type & MT_ALL) == 0)? "" : "=",
3765 bitmask? '&' : '=', iplist);
3766 }
3767 return FAIL;
3768 }
3769 }
3770
3771 /* Either there was no IP list, or the record matched, implying that the
3772 domain is on the list. We now want to find a corresponding TXT record. If an
3773 alternate domain is specified for the TXT record, call this function
3774 recursively to look that up; this has the side effect of re-checking that
3775 there is indeed an A record at the alternate domain. */
3776
3777 if (domain_txt != domain)
3778 return one_check_dnsbl(domain_txt, domain_txt, keydomain, prepend, NULL,
3779 FALSE, match_type, defer_return);
3780
3781 /* If there is no alternate domain, look up a TXT record in the main domain
3782 if it has not previously been cached. */
3783
3784 if (!cb->text_set)
3785 {
3786 cb->text_set = TRUE;
3787 if (dns_basic_lookup(&dnsa, query, T_TXT) == DNS_SUCCEED)
3788 {
3789 dns_record *rr;
3790 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
3791 rr != NULL;
3792 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3793 if (rr->type == T_TXT) break;
3794 if (rr != NULL)
3795 {
3796 int len = (rr->data)[0];
3797 if (len > 511) len = 127;
3798 store_pool = POOL_PERM;
3799 cb->text = string_sprintf("%.*s", len, (const uschar *)(rr->data+1));
3800 store_pool = old_pool;
3801 }
3802 }
3803 }
3804
3805 dnslist_value = addlist;
3806 dnslist_text = cb->text;
3807 return OK;
3808 }
3809
3810 /* There was a problem with the DNS lookup */
3811
3812 if (cb->rc != DNS_NOMATCH && cb->rc != DNS_NODATA)
3813 {
3814 log_write(L_dnslist_defer, LOG_MAIN,
3815 "DNS list lookup defer (probably timeout) for %s: %s", query,
3816 (defer_return == OK)? US"assumed in list" :
3817 (defer_return == FAIL)? US"assumed not in list" :
3818 US"returned DEFER");
3819 return defer_return;
3820 }
3821
3822 /* No entry was found in the DNS; continue for next domain */
3823
3824 HDEBUG(D_dnsbl)
3825 {
3826 debug_printf("DNS lookup for %s failed\n", query);
3827 debug_printf("=> that means %s is not listed at %s\n",
3828 keydomain, domain);
3829 }
3830
3831 return FAIL;
3832 }
3833
3834
3835
3836
3837 /*************************************************
3838 * Check host against DNS black lists *
3839 *************************************************/
3840
3841 /* This function runs checks against a list of DNS black lists, until one
3842 matches. Each item on the list can be of the form
3843
3844 domain=ip-address/key
3845
3846 The domain is the right-most domain that is used for the query, for example,
3847 blackholes.mail-abuse.org. If the IP address is present, there is a match only
3848 if the DNS lookup returns a matching IP address. Several addresses may be
3849 given, comma-separated, for example: x.y.z=127.0.0.1,127.0.0.2.
3850
3851 If no key is given, what is looked up in the domain is the inverted IP address
3852 of the current client host. If a key is given, it is used to construct the
3853 domain for the lookup. For example:
3854
3855 dsn.rfc-ignorant.org/$sender_address_domain
3856
3857 After finding a match in the DNS, the domain is placed in $dnslist_domain, and
3858 then we check for a TXT record for an error message, and if found, save its
3859 value in $dnslist_text. We also cache everything in a tree, to optimize
3860 multiple lookups.
3861
3862 The TXT record is normally looked up in the same domain as the A record, but
3863 when many lists are combined in a single DNS domain, this will not be a very
3864 specific message. It is possible to specify a different domain for looking up
3865 TXT records; this is given before the main domain, comma-separated. For
3866 example:
3867
3868 dnslists = http.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.2 : \
3869 socks.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.3
3870
3871 The caching ensures that only one lookup in dnsbl.sorbs.net is done.
3872
3873 Note: an address for testing RBL is 192.203.178.39
3874 Note: an address for testing DUL is 192.203.178.4
3875 Note: a domain for testing RFCI is example.tld.dsn.rfc-ignorant.org
3876
3877 Arguments:
3878 where the acl type
3879 listptr the domain/address/data list
3880 log_msgptr log message on error
3881
3882 Returns: OK successful lookup (i.e. the address is on the list), or
3883 lookup deferred after +include_unknown
3884 FAIL name not found, or no data found for the given type, or
3885 lookup deferred after +exclude_unknown (default)
3886 DEFER lookup failure, if +defer_unknown was set
3887 */
3888
3889 int
3890 verify_check_dnsbl(int where, const uschar ** listptr, uschar ** log_msgptr)
3891 {
3892 int sep = 0;
3893 int defer_return = FAIL;
3894 const uschar *list = *listptr;
3895 uschar *domain;
3896 uschar *s;
3897 uschar buffer[1024];
3898 uschar revadd[128]; /* Long enough for IPv6 address */
3899
3900 /* Indicate that the inverted IP address is not yet set up */
3901
3902 revadd[0] = 0;
3903
3904 /* In case this is the first time the DNS resolver is being used. */
3905
3906 dns_init(FALSE, FALSE, FALSE); /*XXX dnssec? */
3907
3908 /* Loop through all the domains supplied, until something matches */
3909
3910 while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
3911 {
3912 int rc;
3913 BOOL bitmask = FALSE;
3914 int match_type = 0;
3915 uschar *domain_txt;
3916 uschar *comma;
3917 uschar *iplist;
3918 uschar *key;
3919
3920 HDEBUG(D_dnsbl) debug_printf("DNS list check: %s\n", domain);
3921
3922 /* Deal with special values that change the behaviour on defer */
3923
3924 if (domain[0] == '+')
3925 {
3926 if (strcmpic(domain, US"+include_unknown") == 0) defer_return = OK;
3927 else if (strcmpic(domain, US"+exclude_unknown") == 0) defer_return = FAIL;
3928 else if (strcmpic(domain, US"+defer_unknown") == 0) defer_return = DEFER;
3929 else
3930 log_write(0, LOG_MAIN|LOG_PANIC, "unknown item in dnslist (ignored): %s",
3931 domain);
3932 continue;
3933 }
3934
3935 /* See if there's explicit data to be looked up */
3936
3937 if ((key = Ustrchr(domain, '/'))) *key++ = 0;
3938
3939 /* See if there's a list of addresses supplied after the domain name. This is
3940 introduced by an = or a & character; if preceded by = we require all matches
3941 and if preceded by ! we invert the result. */
3942
3943 if (!(iplist = Ustrchr(domain, '=')))
3944 {
3945 bitmask = TRUE;
3946 iplist = Ustrchr(domain, '&');
3947 }
3948
3949 if (iplist) /* Found either = or & */
3950 {
3951 if (iplist > domain && iplist[-1] == '!') /* Handle preceding ! */
3952 {
3953 match_type |= MT_NOT;
3954 iplist[-1] = 0;
3955 }
3956
3957 *iplist++ = 0; /* Terminate domain, move on */
3958
3959 /* If we found = (bitmask == FALSE), check for == or =& */
3960
3961 if (!bitmask && (*iplist == '=' || *iplist == '&'))
3962 {
3963 bitmask = *iplist++ == '&';
3964 match_type |= MT_ALL;
3965 }
3966 }
3967
3968
3969 /* If there is a comma in the domain, it indicates that a second domain for
3970 looking up TXT records is provided, before the main domain. Otherwise we must
3971 set domain_txt == domain. */
3972
3973 domain_txt = domain;
3974 comma = Ustrchr(domain, ',');
3975 if (comma != NULL)
3976 {
3977 *comma++ = 0;
3978 domain = comma;
3979 }
3980
3981 /* Check that what we have left is a sensible domain name. There is no reason
3982 why these domains should in fact use the same syntax as hosts and email
3983 domains, but in practice they seem to. However, there is little point in
3984 actually causing an error here, because that would no doubt hold up incoming
3985 mail. Instead, I'll just log it. */
3986
3987 for (s = domain; *s != 0; s++)
3988 {
3989 if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_')
3990 {
3991 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
3992 "strange characters - is this right?", domain);
3993 break;
3994 }
3995 }
3996
3997 /* Check the alternate domain if present */
3998
3999 if (domain_txt != domain) for (s = domain_txt; *s != 0; s++)
4000 {
4001 if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_')
4002 {
4003 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
4004 "strange characters - is this right?", domain_txt);
4005 break;
4006 }
4007 }
4008
4009 /* If there is no key string, construct the query by adding the domain name
4010 onto the inverted host address, and perform a single DNS lookup. */
4011
4012 if (key == NULL)
4013 {
4014 if (where == ACL_WHERE_NOTSMTP_START || where == ACL_WHERE_NOTSMTP)
4015 {
4016 *log_msgptr = string_sprintf
4017 ("cannot test auto-keyed dnslists condition in %s ACL",
4018 acl_wherenames[where]);
4019 return ERROR;
4020 }
4021 if (sender_host_address == NULL) return FAIL; /* can never match */
4022 if (revadd[0] == 0) invert_address(revadd, sender_host_address);
4023 rc = one_check_dnsbl(domain, domain_txt, sender_host_address, revadd,
4024 iplist, bitmask, match_type, defer_return);
4025 if (rc == OK)
4026 {
4027 dnslist_domain = string_copy(domain_txt);
4028 dnslist_matched = string_copy(sender_host_address);
4029 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
4030 sender_host_address, dnslist_domain);
4031 }
4032 if (rc != FAIL) return rc; /* OK or DEFER */
4033 }
4034
4035 /* If there is a key string, it can be a list of domains or IP addresses to
4036 be concatenated with the main domain. */
4037
4038 else
4039 {
4040 int keysep = 0;
4041 BOOL defer = FALSE;
4042 uschar *keydomain;
4043 uschar keybuffer[256];
4044 uschar keyrevadd[128];
4045
4046 while ((keydomain = string_nextinlist(CUSS &key, &keysep, keybuffer,
4047 sizeof(keybuffer))) != NULL)
4048 {
4049 uschar *prepend = keydomain;
4050
4051 if (string_is_ip_address(keydomain, NULL) != 0)
4052 {
4053 invert_address(keyrevadd, keydomain);
4054 prepend = keyrevadd;
4055 }
4056
4057 rc = one_check_dnsbl(domain, domain_txt, keydomain, prepend, iplist,
4058 bitmask, match_type, defer_re