1eff49f4966952a889349a68ece0491d3196c86b
[exim.git] / src / src / verify.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
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(int, char, uschar **, int);
43
44
45
46 /*************************************************
47 * Retrieve a callout cache record *
48 *************************************************/
49
50 /* If a record exists, check whether it has expired.
51
52 Arguments:
53 dbm_file an open hints file
54 key the record key
55 type "address" or "domain"
56 positive_expire expire time for positive records
57 negative_expire expire time for negative records
58
59 Returns: the cache record if a non-expired one exists, else NULL
60 */
61
62 static dbdata_callout_cache *
63 get_callout_cache_record(open_db *dbm_file, const uschar *key, uschar *type,
64 int positive_expire, int negative_expire)
65 {
66 BOOL negative;
67 int length, expire;
68 time_t now;
69 dbdata_callout_cache *cache_record;
70
71 if (!(cache_record = dbfn_read_with_length(dbm_file, key, &length)))
72 {
73 HDEBUG(D_verify) debug_printf("callout cache: no %s record found for %s\n", type, key);
74 return NULL;
75 }
76
77 /* We treat a record as "negative" if its result field is not positive, or if
78 it is a domain record and the postmaster field is negative. */
79
80 negative = cache_record->result != ccache_accept ||
81 (type[0] == 'd' && cache_record->postmaster_result == ccache_reject);
82 expire = negative? negative_expire : positive_expire;
83 now = time(NULL);
84
85 if (now - cache_record->time_stamp > expire)
86 {
87 HDEBUG(D_verify) debug_printf("callout cache: %s record expired for %s\n", type, key);
88 return NULL;
89 }
90
91 /* If this is a non-reject domain record, check for the obsolete format version
92 that doesn't have the postmaster and random timestamps, by looking at the
93 length. If so, copy it to a new-style block, replicating the record's
94 timestamp. Then check the additional timestamps. (There's no point wasting
95 effort if connections are rejected.) */
96
97 if (type[0] == 'd' && cache_record->result != ccache_reject)
98 {
99 if (length == sizeof(dbdata_callout_cache_obs))
100 {
101 dbdata_callout_cache *new = store_get(sizeof(dbdata_callout_cache));
102 memcpy(new, cache_record, length);
103 new->postmaster_stamp = new->random_stamp = new->time_stamp;
104 cache_record = new;
105 }
106
107 if (now - cache_record->postmaster_stamp > expire)
108 cache_record->postmaster_result = ccache_unknown;
109
110 if (now - cache_record->random_stamp > expire)
111 cache_record->random_result = ccache_unknown;
112 }
113
114 HDEBUG(D_verify) debug_printf("callout cache: found %s record for %s\n", type, key);
115 return cache_record;
116 }
117
118
119
120 /* Check the callout cache.
121 Options * pm_mailfrom may be modified by cache partial results.
122
123 Return: TRUE if result found
124 */
125
126 static BOOL
127 cached_callout_lookup(address_item * addr, uschar * address_key,
128 uschar * from_address, int * opt_ptr, uschar ** pm_ptr,
129 int * yield, uschar ** failure_ptr,
130 dbdata_callout_cache * new_domain_record, int * old_domain_res)
131 {
132 int options = *opt_ptr;
133 open_db dbblock;
134 open_db *dbm_file = NULL;
135
136 /* Open the callout cache database, it it exists, for reading only at this
137 stage, unless caching has been disabled. */
138
139 if (options & vopt_callout_no_cache)
140 {
141 HDEBUG(D_verify) debug_printf("callout cache: disabled by no_cache\n");
142 }
143 else if (!(dbm_file = dbfn_open(US"callout", O_RDWR, &dbblock, FALSE)))
144 {
145 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
146 }
147 else
148 {
149 /* If a cache database is available see if we can avoid the need to do an
150 actual callout by making use of previously-obtained data. */
151
152 dbdata_callout_cache_address * cache_address_record;
153 dbdata_callout_cache * cache_record = get_callout_cache_record(dbm_file,
154 addr->domain, US"domain",
155 callout_cache_domain_positive_expire, callout_cache_domain_negative_expire);
156
157 /* If an unexpired cache record was found for this domain, see if the callout
158 process can be short-circuited. */
159
160 if (cache_record)
161 {
162 /* In most cases, if an early command (up to and including MAIL FROM:<>)
163 was rejected, there is no point carrying on. The callout fails. However, if
164 we are doing a recipient verification with use_sender or use_postmaster
165 set, a previous failure of MAIL FROM:<> doesn't count, because this time we
166 will be using a non-empty sender. We have to remember this situation so as
167 not to disturb the cached domain value if this whole verification succeeds
168 (we don't want it turning into "accept"). */
169
170 *old_domain_res = cache_record->result;
171
172 if ( cache_record->result == ccache_reject
173 || *from_address == 0 && cache_record->result == ccache_reject_mfnull)
174 {
175 setflag(addr, af_verify_nsfail);
176 HDEBUG(D_verify)
177 debug_printf("callout cache: domain gave initial rejection, or "
178 "does not accept HELO or MAIL FROM:<>\n");
179 setflag(addr, af_verify_nsfail);
180 addr->user_message = US"(result of an earlier callout reused).";
181 *yield = FAIL;
182 *failure_ptr = US"mail";
183 dbfn_close(dbm_file);
184 return TRUE;
185 }
186
187 /* If a previous check on a "random" local part was accepted, we assume
188 that the server does not do any checking on local parts. There is therefore
189 no point in doing the callout, because it will always be successful. If a
190 random check previously failed, arrange not to do it again, but preserve
191 the data in the new record. If a random check is required but hasn't been
192 done, skip the remaining cache processing. */
193
194 if (options & vopt_callout_random) switch(cache_record->random_result)
195 {
196 case ccache_accept:
197 HDEBUG(D_verify)
198 debug_printf("callout cache: domain accepts random addresses\n");
199 dbfn_close(dbm_file);
200 return TRUE; /* Default yield is OK */
201
202 case ccache_reject:
203 HDEBUG(D_verify)
204 debug_printf("callout cache: domain rejects random addresses\n");
205 *opt_ptr = options & ~vopt_callout_random;
206 new_domain_record->random_result = ccache_reject;
207 new_domain_record->random_stamp = cache_record->random_stamp;
208 break;
209
210 default:
211 HDEBUG(D_verify)
212 debug_printf("callout cache: need to check random address handling "
213 "(not cached or cache expired)\n");
214 dbfn_close(dbm_file);
215 return FALSE;
216 }
217
218 /* If a postmaster check is requested, but there was a previous failure,
219 there is again no point in carrying on. If a postmaster check is required,
220 but has not been done before, we are going to have to do a callout, so skip
221 remaining cache processing. */
222
223 if (*pm_ptr)
224 {
225 if (cache_record->postmaster_result == ccache_reject)
226 {
227 setflag(addr, af_verify_pmfail);
228 HDEBUG(D_verify)
229 debug_printf("callout cache: domain does not accept "
230 "RCPT TO:<postmaster@domain>\n");
231 *yield = FAIL;
232 *failure_ptr = US"postmaster";
233 setflag(addr, af_verify_pmfail);
234 addr->user_message = US"(result of earlier verification reused).";
235 dbfn_close(dbm_file);
236 return TRUE;
237 }
238 if (cache_record->postmaster_result == ccache_unknown)
239 {
240 HDEBUG(D_verify)
241 debug_printf("callout cache: need to check RCPT "
242 "TO:<postmaster@domain> (not cached or cache expired)\n");
243 dbfn_close(dbm_file);
244 return FALSE;
245 }
246
247 /* If cache says OK, set pm_mailfrom NULL to prevent a redundant
248 postmaster check if the address itself has to be checked. Also ensure
249 that the value in the cache record is preserved (with its old timestamp).
250 */
251
252 HDEBUG(D_verify) debug_printf("callout cache: domain accepts RCPT "
253 "TO:<postmaster@domain>\n");
254 *pm_ptr = NULL;
255 new_domain_record->postmaster_result = ccache_accept;
256 new_domain_record->postmaster_stamp = cache_record->postmaster_stamp;
257 }
258 }
259
260 /* We can't give a result based on information about the domain. See if there
261 is an unexpired cache record for this specific address (combined with the
262 sender address if we are doing a recipient callout with a non-empty sender).
263 */
264
265 if (!(cache_address_record = (dbdata_callout_cache_address *)
266 get_callout_cache_record(dbm_file, address_key, US"address",
267 callout_cache_positive_expire, callout_cache_negative_expire)))
268 {
269 dbfn_close(dbm_file);
270 return FALSE;
271 }
272
273 if (cache_address_record->result == ccache_accept)
274 {
275 HDEBUG(D_verify)
276 debug_printf("callout cache: address record is positive\n");
277 }
278 else
279 {
280 HDEBUG(D_verify)
281 debug_printf("callout cache: address record is negative\n");
282 addr->user_message = US"Previous (cached) callout verification failure";
283 *failure_ptr = US"recipient";
284 *yield = FAIL;
285 }
286
287 /* Close the cache database while we actually do the callout for real. */
288
289 dbfn_close(dbm_file);
290 return TRUE;
291 }
292 return FALSE;
293 }
294
295
296 /* Write results to callout cache
297 */
298 static void
299 cache_callout_write(dbdata_callout_cache * dom_rec, const uschar * domain,
300 int done, dbdata_callout_cache_address * addr_rec, uschar * address_key)
301 {
302 open_db dbblock;
303 open_db *dbm_file = NULL;
304
305 /* If we get here with done == TRUE, a successful callout happened, and yield
306 will be set OK or FAIL according to the response to the RCPT command.
307 Otherwise, we looped through the hosts but couldn't complete the business.
308 However, there may be domain-specific information to cache in both cases.
309
310 The value of the result field in the new_domain record is ccache_unknown if
311 there was an error before or with MAIL FROM:, and errno was not zero,
312 implying some kind of I/O error. We don't want to write the cache in that case.
313 Otherwise the value is ccache_accept, ccache_reject, or ccache_reject_mfnull. */
314
315 if (dom_rec->result != ccache_unknown)
316 if (!(dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE)))
317 {
318 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
319 }
320 else
321 {
322 (void)dbfn_write(dbm_file, domain, dom_rec,
323 (int)sizeof(dbdata_callout_cache));
324 HDEBUG(D_verify) debug_printf("wrote callout cache domain record for %s:\n"
325 " result=%d postmaster=%d random=%d\n",
326 domain,
327 dom_rec->result,
328 dom_rec->postmaster_result,
329 dom_rec->random_result);
330 }
331
332 /* If a definite result was obtained for the callout, cache it unless caching
333 is disabled. */
334
335 if (done && addr_rec->result != ccache_unknown)
336 {
337 if (!dbm_file)
338 dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE);
339 if (!dbm_file)
340 {
341 HDEBUG(D_verify) debug_printf("no callout cache available\n");
342 }
343 else
344 {
345 (void)dbfn_write(dbm_file, address_key, addr_rec,
346 (int)sizeof(dbdata_callout_cache_address));
347 HDEBUG(D_verify) debug_printf("wrote %s callout cache address record for %s\n",
348 addr_rec->result == ccache_accept ? "positive" : "negative",
349 address_key);
350 }
351 }
352
353 if (dbm_file) dbfn_close(dbm_file);
354 }
355
356
357 /* Cutthrough-multi. If the existing cached cutthrough connection matches
358 the one we would make for a subsequent recipient, use it. Send the RCPT TO
359 and check the result, nonpipelined as it may be wanted immediately for
360 recipient-verification.
361
362 It seems simpler to deal with this case separately from the main callout loop.
363 We will need to remember it has sent, or not, so that rcpt-acl tail code
364 can do it there for the non-rcpt-verify case. For this we keep an addresscount.
365
366 Return: TRUE for a definitive result for the recipient
367 */
368 static int
369 cutthrough_multi(address_item * addr, host_item * host_list,
370 transport_feedback * tf, int * yield)
371 {
372 BOOL done = FALSE;
373 host_item * host;
374
375 if (addr->transport == cutthrough.addr.transport)
376 for (host = host_list; host; host = host->next)
377 if (Ustrcmp(host->address, cutthrough.host.address) == 0)
378 {
379 int host_af;
380 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
381 int port = 25;
382
383 deliver_host = host->name;
384 deliver_host_address = host->address;
385 deliver_host_port = host->port;
386 deliver_domain = addr->domain;
387 transport_name = addr->transport->name;
388
389 host_af = Ustrchr(host->address, ':') ? AF_INET6 : AF_INET;
390
391 if ( !smtp_get_interface(tf->interface, host_af, addr, &interface,
392 US"callout")
393 || !smtp_get_port(tf->port, addr, &port, US"callout")
394 )
395 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
396 addr->message);
397
398 smtp_port_for_connect(host, port);
399
400 if ( ( interface == cutthrough.interface
401 || ( interface
402 && cutthrough.interface
403 && Ustrcmp(interface, cutthrough.interface) == 0
404 ) )
405 && host->port == cutthrough.host.port
406 )
407 {
408 uschar * resp = NULL;
409
410 /* Match! Send the RCPT TO, set done from the response */
411 done =
412 smtp_write_command(&ctblock, SCMD_FLUSH, "RCPT TO:<%.1000s>\r\n",
413 transport_rcpt_address(addr,
414 addr->transport->rcpt_include_affixes)) >= 0 &&
415 cutthrough_response(cutthrough.fd, '2', &resp, CUTTHROUGH_DATA_TIMEOUT) == '2';
416
417 /* This would go horribly wrong if a callout fail was ignored by ACL.
418 We punt by abandoning cutthrough on a reject, like the
419 first-rcpt does. */
420
421 if (done)
422 {
423 address_item * na = store_get(sizeof(address_item));
424 *na = cutthrough.addr;
425 cutthrough.addr = *addr;
426 cutthrough.addr.host_used = &cutthrough.host;
427 cutthrough.addr.next = na;
428
429 cutthrough.nrcpt++;
430 }
431 else
432 {
433 cancel_cutthrough_connection(TRUE, US"recipient rejected");
434 if (!resp || errno == ETIMEDOUT)
435 {
436 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
437 }
438 else if (errno == 0)
439 {
440 if (*resp == 0)
441 Ustrcpy(resp, US"connection dropped");
442
443 addr->message =
444 string_sprintf("response to \"%s\" was: %s",
445 big_buffer, string_printing(resp));
446
447 addr->user_message =
448 string_sprintf("Callout verification failed:\n%s", resp);
449
450 /* Hard rejection ends the process */
451
452 if (resp[0] == '5') /* Address rejected */
453 {
454 *yield = FAIL;
455 done = TRUE;
456 }
457 }
458 }
459 }
460 break; /* host_list */
461 }
462 if (!done)
463 cancel_cutthrough_connection(TRUE, US"incompatible connection");
464 return done;
465 }
466
467
468 /*************************************************
469 * Do callout verification for an address *
470 *************************************************/
471
472 /* This function is called from verify_address() when the address has routed to
473 a host list, and a callout has been requested. Callouts are expensive; that is
474 why a cache is used to improve the efficiency.
475
476 Arguments:
477 addr the address that's been routed
478 host_list the list of hosts to try
479 tf the transport feedback block
480
481 ifstring "interface" option from transport, or NULL
482 portstring "port" option from transport, or NULL
483 protocolstring "protocol" option from transport, or NULL
484 callout the per-command callout timeout
485 callout_overall the overall callout timeout (if < 0 use 4*callout)
486 callout_connect the callout connection timeout (if < 0 use callout)
487 options the verification options - these bits are used:
488 vopt_is_recipient => this is a recipient address
489 vopt_callout_no_cache => don't use callout cache
490 vopt_callout_fullpm => if postmaster check, do full one
491 vopt_callout_random => do the "random" thing
492 vopt_callout_recipsender => use real sender for recipient
493 vopt_callout_recippmaster => use postmaster for recipient
494 vopt_callout_hold => lazy close connection
495 se_mailfrom MAIL FROM address for sender verify; NULL => ""
496 pm_mailfrom if non-NULL, do the postmaster check with this sender
497
498 Returns: OK/FAIL/DEFER
499 */
500
501 static int
502 do_callout(address_item *addr, host_item *host_list, transport_feedback *tf,
503 int callout, int callout_overall, int callout_connect, int options,
504 uschar *se_mailfrom, uschar *pm_mailfrom)
505 {
506 int yield = OK;
507 int old_domain_cache_result = ccache_accept;
508 BOOL done = FALSE;
509 uschar *address_key;
510 uschar *from_address;
511 uschar *random_local_part = NULL;
512 const uschar *save_deliver_domain = deliver_domain;
513 uschar **failure_ptr = options & vopt_is_recipient
514 ? &recipient_verify_failure : &sender_verify_failure;
515 dbdata_callout_cache new_domain_record;
516 dbdata_callout_cache_address new_address_record;
517 time_t callout_start_time;
518
519 new_domain_record.result = ccache_unknown;
520 new_domain_record.postmaster_result = ccache_unknown;
521 new_domain_record.random_result = ccache_unknown;
522
523 memset(&new_address_record, 0, sizeof(new_address_record));
524
525 /* For a recipient callout, the key used for the address cache record must
526 include the sender address if we are using the real sender in the callout,
527 because that may influence the result of the callout. */
528
529 if (options & vopt_is_recipient)
530 if (options & vopt_callout_recipsender)
531 {
532 from_address = sender_address;
533 address_key = string_sprintf("%s/<%s>", addr->address, sender_address);
534 if (cutthrough.delivery) options |= vopt_callout_no_cache;
535 }
536 else if (options & vopt_callout_recippmaster)
537 {
538 from_address = string_sprintf("postmaster@%s", qualify_domain_sender);
539 address_key = string_sprintf("%s/<postmaster@%s>", addr->address,
540 qualify_domain_sender);
541 }
542 else
543 {
544 from_address = US"";
545 address_key = addr->address;
546 }
547
548 /* For a sender callout, we must adjust the key if the mailfrom address is not
549 empty. */
550
551 else
552 {
553 from_address = se_mailfrom ? se_mailfrom : US"";
554 address_key = *from_address
555 ? string_sprintf("%s/<%s>", addr->address, from_address) : addr->address;
556 }
557
558 if (cached_callout_lookup(addr, address_key, from_address,
559 &options, &pm_mailfrom, &yield, failure_ptr,
560 &new_domain_record, &old_domain_cache_result))
561 {
562 cancel_cutthrough_connection(TRUE, US"cache-hit");
563 goto END_CALLOUT;
564 }
565
566 if (!addr->transport)
567 {
568 HDEBUG(D_verify) debug_printf("cannot callout via null transport\n");
569 }
570 else if (Ustrcmp(addr->transport->driver_name, "smtp") != 0)
571 log_write(0, LOG_MAIN|LOG_PANIC|LOG_CONFIG_FOR, "callout transport '%s': %s is non-smtp",
572 addr->transport->name, addr->transport->driver_name);
573 else
574 {
575 smtp_transport_options_block *ob =
576 (smtp_transport_options_block *)addr->transport->options_block;
577 host_item * host;
578
579 /* The information wasn't available in the cache, so we have to do a real
580 callout and save the result in the cache for next time, unless no_cache is set,
581 or unless we have a previously cached negative random result. If we are to test
582 with a random local part, ensure that such a local part is available. If not,
583 log the fact, but carry on without randomising. */
584
585 if (options & vopt_callout_random && callout_random_local_part)
586 if (!(random_local_part = expand_string(callout_random_local_part)))
587 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand "
588 "callout_random_local_part: %s", expand_string_message);
589
590 /* Default the connect and overall callout timeouts if not set, and record the
591 time we are starting so that we can enforce it. */
592
593 if (callout_overall < 0) callout_overall = 4 * callout;
594 if (callout_connect < 0) callout_connect = callout;
595 callout_start_time = time(NULL);
596
597 /* Before doing a real callout, if this is an SMTP connection, flush the SMTP
598 output because a callout might take some time. When PIPELINING is active and
599 there are many recipients, the total time for doing lots of callouts can add up
600 and cause the client to time out. So in this case we forgo the PIPELINING
601 optimization. */
602
603 if (smtp_out && !disable_callout_flush) mac_smtp_fflush();
604
605 clearflag(addr, af_verify_pmfail); /* postmaster callout flag */
606 clearflag(addr, af_verify_nsfail); /* null sender callout flag */
607
608 /* cutthrough-multi: if a nonfirst rcpt has the same routing as the first,
609 and we are holding a cutthrough conn open, we can just append the rcpt to
610 that conn for verification purposes (and later delivery also). Simplest
611 coding means skipping this whole loop and doing the append separately. */
612
613 /* Can we re-use an open cutthrough connection? */
614 if ( cutthrough.fd >= 0
615 && (options & (vopt_callout_recipsender | vopt_callout_recippmaster))
616 == vopt_callout_recipsender
617 && !random_local_part
618 && !pm_mailfrom
619 )
620 done = cutthrough_multi(addr, host_list, tf, &yield);
621
622 /* If we did not use a cached connection, make connections to the hosts
623 and do real callouts. The list of hosts is passed in as an argument. */
624
625 for (host = host_list; host && !done; host = host->next)
626 {
627 int host_af;
628 int port = 25;
629 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
630 smtp_context sx;
631
632 if (!host->address)
633 {
634 DEBUG(D_verify) debug_printf("no IP address for host name %s: skipping\n",
635 host->name);
636 continue;
637 }
638
639 /* Check the overall callout timeout */
640
641 if (time(NULL) - callout_start_time >= callout_overall)
642 {
643 HDEBUG(D_verify) debug_printf("overall timeout for callout exceeded\n");
644 break;
645 }
646
647 /* Set IPv4 or IPv6 */
648
649 host_af = Ustrchr(host->address, ':') ? AF_INET6 : AF_INET;
650
651 /* Expand and interpret the interface and port strings. The latter will not
652 be used if there is a host-specific port (e.g. from a manualroute router).
653 This has to be delayed till now, because they may expand differently for
654 different hosts. If there's a failure, log it, but carry on with the
655 defaults. */
656
657 deliver_host = host->name;
658 deliver_host_address = host->address;
659 deliver_host_port = host->port;
660 deliver_domain = addr->domain;
661 transport_name = addr->transport->name;
662
663 if ( !smtp_get_interface(tf->interface, host_af, addr, &interface,
664 US"callout")
665 || !smtp_get_port(tf->port, addr, &port, US"callout")
666 )
667 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
668 addr->message);
669
670 sx.addrlist = addr;
671 sx.host = host;
672 sx.host_af = host_af,
673 sx.port = port;
674 sx.interface = interface;
675 sx.helo_data = tf->helo_data;
676 sx.tblock = addr->transport;
677 sx.verify = TRUE;
678
679 tls_retry_connection:
680 /* Set the address state so that errors are recorded in it */
681
682 addr->transport_return = PENDING_DEFER;
683 ob->connect_timeout = callout_connect;
684 ob->command_timeout = callout;
685
686 /* Get the channel set up ready for a message (MAIL FROM being the next
687 SMTP command to send. If we tried TLS but it failed, try again without
688 if permitted */
689
690 yield = smtp_setup_conn(&sx, FALSE);
691 #ifdef SUPPORT_TLS
692 if ( yield == DEFER
693 && addr->basic_errno == ERRNO_TLSFAILURE
694 && ob->tls_tempfail_tryclear
695 && verify_check_given_host(&ob->hosts_require_tls, host) != OK
696 )
697 {
698 log_write(0, LOG_MAIN,
699 "%s: callout unencrypted to %s [%s] (not in hosts_require_tls)",
700 addr->message, host->name, host->address);
701 addr->transport_return = PENDING_DEFER;
702 yield = smtp_setup_conn(&sx, TRUE);
703 }
704 #endif
705 if (yield != OK)
706 {
707 errno = addr->basic_errno;
708 transport_name = NULL;
709 deliver_host = deliver_host_address = NULL;
710 deliver_domain = save_deliver_domain;
711
712 /* Failure to accept HELO is cached; this blocks the whole domain for all
713 senders. I/O errors and defer responses are not cached. */
714
715 if (yield == FAIL && (errno == 0 || errno == ERRNO_SMTPCLOSED))
716 {
717 setflag(addr, af_verify_nsfail);
718 new_domain_record.result = ccache_reject;
719 done = TRUE;
720 }
721 else
722 done = FALSE;
723 goto no_conn;
724 }
725
726 /* If we needed to authenticate, smtp_setup_conn() did that. Copy
727 the AUTH info for logging */
728
729 addr->authenticator = client_authenticator;
730 addr->auth_id = client_authenticated_id;
731
732 sx.from_addr = from_address;
733 sx.first_addr = sx.sync_addr = addr;
734 sx.ok = FALSE; /*XXX these 3 last might not be needed for verify? */
735 sx.send_rset = TRUE;
736 sx.completed_addr = FALSE;
737
738 new_domain_record.result = old_domain_cache_result == ccache_reject_mfnull
739 ? ccache_reject_mfnull : ccache_accept;
740
741 /* Do the random local part check first. Temporarily replace the recipient
742 with the "random" value */
743
744 if (random_local_part)
745 {
746 uschar * main_address = addr->address;
747 const uschar * rcpt_domain = addr->domain;
748
749 #ifdef SUPPORT_I18N
750 uschar * errstr = NULL;
751 if ( testflag(addr, af_utf8_downcvt)
752 && (rcpt_domain = string_domain_utf8_to_alabel(rcpt_domain,
753 &errstr), errstr)
754 )
755 {
756 addr->message = errstr;
757 errno = ERRNO_EXPANDFAIL;
758 setflag(addr, af_verify_nsfail);
759 done = FALSE;
760 rcpt_domain = US""; /*XXX errorhandling! */
761 }
762 #endif
763
764 /* This would be ok for 1st rcpt of a cutthrough (the case handled here;
765 subsequents are done in cutthrough_multi()), but no way to
766 handle a subsequent because of the RSET vaporising the MAIL FROM.
767 So refuse to support any. Most cutthrough use will not involve
768 random_local_part, so no loss. */
769 cancel_cutthrough_connection(TRUE, US"random-recipient");
770
771 addr->address = string_sprintf("%s@%.1000s",
772 random_local_part, rcpt_domain);
773 done = FALSE;
774
775 /* If accepted, we aren't going to do any further tests below.
776 Otherwise, cache a real negative response, and get back to the right
777 state to send RCPT. Unless there's some problem such as a dropped
778 connection, we expect to succeed, because the commands succeeded above.
779 However, some servers drop the connection after responding to an
780 invalid recipient, so on (any) error we drop and remake the connection.
781 XXX We don't care about that for postmaster_full. Should we?
782
783 XXX could we add another flag to the context, and have the common
784 code emit the RSET too? Even pipelined after the RCPT...
785 Then the main-verify call could use it if there's to be a subsequent
786 postmaster-verify.
787 The sync_responses() would need to be taught about it and we'd
788 need another return code filtering out to here.
789
790 Avoid using a SIZE option on the MAIL for all random-rcpt checks.
791 */
792
793 sx.avoid_option = OPTION_SIZE;
794
795 /* Remember when we last did a random test */
796 new_domain_record.random_stamp = time(NULL);
797
798 if (smtp_write_mail_and_rcpt_cmds(&sx, &yield) == 0)
799 switch(addr->transport_return)
800 {
801 case PENDING_OK: /* random was accepted, unfortunately */
802 new_domain_record.random_result = ccache_accept;
803 yield = OK; /* Only usable verify result we can return */
804 done = TRUE;
805 goto no_conn;
806 case FAIL: /* rejected: the preferred result */
807 new_domain_record.random_result = ccache_reject;
808 sx.avoid_option = 0;
809
810 /* Between each check, issue RSET, because some servers accept only
811 one recipient after MAIL FROM:<>.
812 XXX We don't care about that for postmaster_full. Should we? */
813
814 if ((done =
815 smtp_write_command(&sx.outblock, SCMD_FLUSH, "RSET\r\n") >= 0 &&
816 smtp_read_response(&sx.inblock, sx.buffer, sizeof(sx.buffer),
817 '2', callout)))
818 break;
819
820 HDEBUG(D_acl|D_v)
821 debug_printf_indent("problem after random/rset/mfrom; reopen conn\n");
822 random_local_part = NULL;
823 #ifdef SUPPORT_TLS
824 tls_close(FALSE, TLS_SHUTDOWN_NOWAIT);
825 #endif
826 HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP(close)>>\n");
827 (void)close(sx.inblock.sock);
828 sx.inblock.sock = sx.outblock.sock = -1;
829 #ifndef DISABLE_EVENT
830 (void) event_raise(addr->transport->event_action,
831 US"tcp:close", NULL);
832 #endif
833 addr->address = main_address;
834 addr->transport_return = PENDING_DEFER;
835 sx.first_addr = sx.sync_addr = addr;
836 sx.ok = FALSE;
837 sx.send_rset = TRUE;
838 sx.completed_addr = FALSE;
839 goto tls_retry_connection;
840 case DEFER: /* 4xx response to random */
841 break; /* Just to be clear. ccache_unknown, !done. */
842 }
843
844 /* Re-setup for main verify, or for the error message when failing */
845 addr->address = main_address;
846 addr->transport_return = PENDING_DEFER;
847 sx.first_addr = sx.sync_addr = addr;
848 sx.ok = FALSE;
849 sx.send_rset = TRUE;
850 sx.completed_addr = FALSE;
851 }
852 else
853 done = TRUE;
854
855 /* Main verify. For rcpt-verify use SIZE if we know it and we're not cacheing;
856 for sndr-verify never use it. */
857
858 if (done)
859 {
860 if (!(options & vopt_is_recipient && options & vopt_callout_no_cache))
861 sx.avoid_option = OPTION_SIZE;
862
863 done = FALSE;
864 switch(smtp_write_mail_and_rcpt_cmds(&sx, &yield))
865 {
866 case 0: switch(addr->transport_return) /* ok so far */
867 {
868 case PENDING_OK: done = TRUE;
869 new_address_record.result = ccache_accept;
870 break;
871 case FAIL: done = TRUE;
872 yield = FAIL;
873 *failure_ptr = US"recipient";
874 new_address_record.result = ccache_reject;
875 break;
876 default: break;
877 }
878 break;
879
880 case -1: /* MAIL response error */
881 *failure_ptr = US"mail";
882 if (errno == 0 && sx.buffer[0] == '5')
883 {
884 setflag(addr, af_verify_nsfail);
885 if (from_address[0] == 0)
886 new_domain_record.result = ccache_reject_mfnull;
887 }
888 break;
889 /* non-MAIL read i/o error */
890 /* non-MAIL response timeout */
891 /* internal error; channel still usable */
892 default: break; /* transmit failed */
893 }
894 }
895
896 addr->auth_sndr = client_authenticated_sender;
897
898 deliver_host = deliver_host_address = NULL;
899 deliver_domain = save_deliver_domain;
900
901 /* Do postmaster check if requested; if a full check is required, we
902 check for RCPT TO:<postmaster> (no domain) in accordance with RFC 821. */
903
904 if (done && pm_mailfrom)
905 {
906 /* Could possibly shift before main verify, just above, and be ok
907 for cutthrough. But no way to handle a subsequent rcpt, so just
908 refuse any */
909 cancel_cutthrough_connection(TRUE, US"postmaster verify");
910 HDEBUG(D_acl|D_v) debug_printf_indent("Cutthrough cancelled by presence of postmaster verify\n");
911
912 done = smtp_write_command(&sx.outblock, SCMD_FLUSH, "RSET\r\n") >= 0
913 && smtp_read_response(&sx.inblock, sx.buffer,
914 sizeof(sx.buffer), '2', callout);
915
916 if (done)
917 {
918 uschar * main_address = addr->address;
919
920 /*XXX oops, affixes */
921 addr->address = string_sprintf("postmaster@%.1000s", addr->domain);
922 addr->transport_return = PENDING_DEFER;
923
924 sx.from_addr = pm_mailfrom;
925 sx.first_addr = sx.sync_addr = addr;
926 sx.ok = FALSE;
927 sx.send_rset = TRUE;
928 sx.completed_addr = FALSE;
929 sx.avoid_option = OPTION_SIZE;
930
931 if( smtp_write_mail_and_rcpt_cmds(&sx, &yield) == 0
932 && addr->transport_return == PENDING_OK
933 )
934 done = TRUE;
935 else
936 done = (options & vopt_callout_fullpm) != 0
937 && smtp_write_command(&sx.outblock, SCMD_FLUSH,
938 "RCPT TO:<postmaster>\r\n") >= 0
939 && smtp_read_response(&sx.inblock, sx.buffer,
940 sizeof(sx.buffer), '2', callout);
941
942 /* Sort out the cache record */
943
944 new_domain_record.postmaster_stamp = time(NULL);
945
946 if (done)
947 new_domain_record.postmaster_result = ccache_accept;
948 else if (errno == 0 && sx.buffer[0] == '5')
949 {
950 *failure_ptr = US"postmaster";
951 setflag(addr, af_verify_pmfail);
952 new_domain_record.postmaster_result = ccache_reject;
953 }
954
955 addr->address = main_address;
956 }
957 }
958 /* For any failure of the main check, other than a negative response, we just
959 close the connection and carry on. We can identify a negative response by the
960 fact that errno is zero. For I/O errors it will be non-zero
961
962 Set up different error texts for logging and for sending back to the caller
963 as an SMTP response. Log in all cases, using a one-line format. For sender
964 callouts, give a full response to the caller, but for recipient callouts,
965 don't give the IP address because this may be an internal host whose identity
966 is not to be widely broadcast. */
967
968 no_conn:
969 switch(errno)
970 {
971 case ETIMEDOUT:
972 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
973 sx.send_quit = FALSE;
974 break;
975
976 #ifdef SUPPORT_I18N
977 case ERRNO_UTF8_FWD:
978 {
979 extern int acl_where; /* src/acl.c */
980 errno = 0;
981 addr->message = string_sprintf(
982 "response to \"EHLO\" did not include SMTPUTF8");
983 addr->user_message = acl_where == ACL_WHERE_RCPT
984 ? US"533 no support for internationalised mailbox name"
985 : US"550 mailbox unavailable";
986 yield = FAIL;
987 done = TRUE;
988 }
989 break;
990 #endif
991 case ECONNREFUSED:
992 sx.send_quit = FALSE;
993 break;
994
995 case 0:
996 if (*sx.buffer == 0) Ustrcpy(sx.buffer, US"connection dropped");
997
998 /*XXX test here is ugly; seem to have a split of responsibility for
999 building this message. Need to rationalise. Where is it done
1000 before here, and when not?
1001 Not == 5xx resp to MAIL on main-verify
1002 */
1003 if (!addr->message) addr->message =
1004 string_sprintf("response to \"%s\" was: %s",
1005 big_buffer, string_printing(sx.buffer));
1006
1007 addr->user_message = options & vopt_is_recipient
1008 ? string_sprintf("Callout verification failed:\n%s", sx.buffer)
1009 : string_sprintf("Called: %s\nSent: %s\nResponse: %s",
1010 host->address, big_buffer, sx.buffer);
1011
1012 /* Hard rejection ends the process */
1013
1014 if (sx.buffer[0] == '5') /* Address rejected */
1015 {
1016 yield = FAIL;
1017 done = TRUE;
1018 }
1019 break;
1020 }
1021
1022 /* End the SMTP conversation and close the connection. */
1023
1024 /* Cutthrough - on a successful connect and recipient-verify with
1025 use-sender and we are 1st rcpt and have no cutthrough conn so far
1026 here is where we want to leave the conn open. Ditto for a lazy-close
1027 verify. */
1028
1029 if (cutthrough.delivery)
1030 {
1031 if (addr->transport->filter_command)
1032 {
1033 cutthrough.delivery= FALSE;
1034 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of transport filter\n");
1035 }
1036 #ifndef DISABLE_DKIM
1037 if (ob->dkim.dkim_domain)
1038 {
1039 cutthrough.delivery= FALSE;
1040 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of DKIM signing\n");
1041 }
1042 #endif
1043 #ifdef EXPERIMENTAL_ARC
1044 if (ob->arc_sign)
1045 {
1046 cutthrough.delivery= FALSE;
1047 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of ARC signing\n");
1048 }
1049 #endif
1050 }
1051
1052 if ( (cutthrough.delivery || options & vopt_callout_hold)
1053 && rcpt_count == 1
1054 && done
1055 && yield == OK
1056 && (options & (vopt_callout_recipsender|vopt_callout_recippmaster|vopt_success_on_redirect))
1057 == vopt_callout_recipsender
1058 && !random_local_part
1059 && !pm_mailfrom
1060 && cutthrough.fd < 0
1061 && !sx.lmtp
1062 )
1063 {
1064 HDEBUG(D_acl|D_v) debug_printf_indent("holding verify callout open for %s\n",
1065 cutthrough.delivery
1066 ? "cutthrough delivery" : "potential further verifies and delivery");
1067
1068 cutthrough.callout_hold_only = !cutthrough.delivery;
1069 cutthrough.is_tls = tls_out.active >= 0;
1070 cutthrough.fd = sx.outblock.sock; /* We assume no buffer in use in the outblock */
1071 cutthrough.nrcpt = 1;
1072 cutthrough.transport = addr->transport->name;
1073 cutthrough.interface = interface;
1074 cutthrough.snd_port = sending_port;
1075 cutthrough.peer_options = smtp_peer_options;
1076 cutthrough.host = *host;
1077 {
1078 int oldpool = store_pool;
1079 store_pool = POOL_PERM;
1080 cutthrough.snd_ip = string_copy(sending_ip_address);
1081 cutthrough.host.name = string_copy(host->name);
1082 cutthrough.host.address = string_copy(host->address);
1083 store_pool = oldpool;
1084 }
1085 cutthrough.addr = *addr; /* Save the address_item for later logging */
1086 cutthrough.addr.next = NULL;
1087 cutthrough.addr.host_used = &cutthrough.host;
1088 if (addr->parent)
1089 *(cutthrough.addr.parent = store_get(sizeof(address_item))) =
1090 *addr->parent;
1091 ctblock.buffer = ctbuffer;
1092 ctblock.buffersize = sizeof(ctbuffer);
1093 ctblock.ptr = ctbuffer;
1094 /* ctblock.cmd_count = 0; ctblock.authenticating = FALSE; */
1095 ctblock.sock = cutthrough.fd;
1096 }
1097 else
1098 {
1099 /* Ensure no cutthrough on multiple verifies that were incompatible */
1100 if (options & vopt_callout_recipsender)
1101 cancel_cutthrough_connection(TRUE, US"not usable for cutthrough");
1102 if (sx.send_quit)
1103 {
1104 (void) smtp_write_command(&sx.outblock, SCMD_FLUSH, "QUIT\r\n");
1105
1106 /* Wait a short time for response, and discard it */
1107 smtp_read_response(&sx.inblock, sx.buffer, sizeof(sx.buffer),
1108 '2', 1);
1109 }
1110
1111 if (sx.inblock.sock >= 0)
1112 {
1113 #ifdef SUPPORT_TLS
1114 tls_close(FALSE, TLS_SHUTDOWN_NOWAIT);
1115 #endif
1116 HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP(close)>>\n");
1117 (void)close(sx.inblock.sock);
1118 sx.inblock.sock = sx.outblock.sock = -1;
1119 #ifndef DISABLE_EVENT
1120 (void) event_raise(addr->transport->event_action, US"tcp:close", NULL);
1121 #endif
1122 }
1123 }
1124
1125 if (!done || yield != OK)
1126 addr->message = string_sprintf("%s [%s] : %s", host->name, host->address,
1127 addr->message);
1128 } /* Loop through all hosts, while !done */
1129 }
1130
1131 /* If we get here with done == TRUE, a successful callout happened, and yield
1132 will be set OK or FAIL according to the response to the RCPT command.
1133 Otherwise, we looped through the hosts but couldn't complete the business.
1134 However, there may be domain-specific information to cache in both cases. */
1135
1136 if (!(options & vopt_callout_no_cache))
1137 cache_callout_write(&new_domain_record, addr->domain,
1138 done, &new_address_record, address_key);
1139
1140 /* Failure to connect to any host, or any response other than 2xx or 5xx is a
1141 temporary error. If there was only one host, and a response was received, leave
1142 it alone if supplying details. Otherwise, give a generic response. */
1143
1144 if (!done)
1145 {
1146 uschar * dullmsg = string_sprintf("Could not complete %s verify callout",
1147 options & vopt_is_recipient ? "recipient" : "sender");
1148 yield = DEFER;
1149
1150 addr->message = host_list->next || !addr->message
1151 ? dullmsg : string_sprintf("%s: %s", dullmsg, addr->message);
1152
1153 addr->user_message = smtp_return_error_details
1154 ? string_sprintf("%s for <%s>.\n"
1155 "The mail server(s) for the domain may be temporarily unreachable, or\n"
1156 "they may be permanently unreachable from this server. In the latter case,\n%s",
1157 dullmsg, addr->address,
1158 options & vopt_is_recipient
1159 ? "the address will never be accepted."
1160 : "you need to change the address or create an MX record for its domain\n"
1161 "if it is supposed to be generally accessible from the Internet.\n"
1162 "Talk to your mail administrator for details.")
1163 : dullmsg;
1164
1165 /* Force a specific error code */
1166
1167 addr->basic_errno = ERRNO_CALLOUTDEFER;
1168 }
1169
1170 /* Come here from within the cache-reading code on fast-track exit. */
1171
1172 END_CALLOUT:
1173 tls_modify_variables(&tls_in);
1174 return yield;
1175 }
1176
1177
1178
1179 /* Called after recipient-acl to get a cutthrough connection open when
1180 one was requested and a recipient-verify wasn't subsequently done.
1181 */
1182 int
1183 open_cutthrough_connection( address_item * addr )
1184 {
1185 address_item addr2;
1186 int rc;
1187
1188 /* Use a recipient-verify-callout to set up the cutthrough connection. */
1189 /* We must use a copy of the address for verification, because it might
1190 get rewritten. */
1191
1192 addr2 = *addr;
1193 HDEBUG(D_acl) debug_printf_indent("----------- %s cutthrough setup ------------\n",
1194 rcpt_count > 1 ? "more" : "start");
1195 rc = verify_address(&addr2, NULL,
1196 vopt_is_recipient | vopt_callout_recipsender | vopt_callout_no_cache,
1197 CUTTHROUGH_CMD_TIMEOUT, -1, -1,
1198 NULL, NULL, NULL);
1199 addr->message = addr2.message;
1200 addr->user_message = addr2.user_message;
1201 HDEBUG(D_acl) debug_printf_indent("----------- end cutthrough setup ------------\n");
1202 return rc;
1203 }
1204
1205
1206
1207 /* Send given number of bytes from the buffer */
1208 static BOOL
1209 cutthrough_send(int n)
1210 {
1211 if(cutthrough.fd < 0)
1212 return TRUE;
1213
1214 if(
1215 #ifdef SUPPORT_TLS
1216 tls_out.active == cutthrough.fd ? tls_write(FALSE, ctblock.buffer, n, FALSE) :
1217 #endif
1218 send(cutthrough.fd, ctblock.buffer, n, 0) > 0
1219 )
1220 {
1221 transport_count += n;
1222 ctblock.ptr= ctblock.buffer;
1223 return TRUE;
1224 }
1225
1226 HDEBUG(D_transport|D_acl) debug_printf_indent("cutthrough_send failed: %s\n", strerror(errno));
1227 return FALSE;
1228 }
1229
1230
1231
1232 static BOOL
1233 _cutthrough_puts(uschar * cp, int n)
1234 {
1235 while(n--)
1236 {
1237 if(ctblock.ptr >= ctblock.buffer+ctblock.buffersize)
1238 if(!cutthrough_send(ctblock.buffersize))
1239 return FALSE;
1240
1241 *ctblock.ptr++ = *cp++;
1242 }
1243 return TRUE;
1244 }
1245
1246 /* Buffered output of counted data block. Return boolean success */
1247 static BOOL
1248 cutthrough_puts(uschar * cp, int n)
1249 {
1250 if (cutthrough.fd < 0) return TRUE;
1251 if (_cutthrough_puts(cp, n)) return TRUE;
1252 cancel_cutthrough_connection(TRUE, US"transmit failed");
1253 return FALSE;
1254 }
1255
1256 void
1257 cutthrough_data_puts(uschar * cp, int n)
1258 {
1259 if (cutthrough.delivery) (void) cutthrough_puts(cp, n);
1260 return;
1261 }
1262
1263
1264 static BOOL
1265 _cutthrough_flush_send(void)
1266 {
1267 int n = ctblock.ptr - ctblock.buffer;
1268
1269 if(n>0)
1270 if(!cutthrough_send(n))
1271 return FALSE;
1272 return TRUE;
1273 }
1274
1275
1276 /* Send out any bufferred output. Return boolean success. */
1277 BOOL
1278 cutthrough_flush_send(void)
1279 {
1280 if (_cutthrough_flush_send()) return TRUE;
1281 cancel_cutthrough_connection(TRUE, US"transmit failed");
1282 return FALSE;
1283 }
1284
1285
1286 static BOOL
1287 cutthrough_put_nl(void)
1288 {
1289 return cutthrough_puts(US"\r\n", 2);
1290 }
1291
1292
1293 void
1294 cutthrough_data_put_nl(void)
1295 {
1296 cutthrough_data_puts(US"\r\n", 2);
1297 }
1298
1299
1300 /* Get and check response from cutthrough target */
1301 static uschar
1302 cutthrough_response(int fd, char expect, uschar ** copy, int timeout)
1303 {
1304 smtp_inblock inblock;
1305 uschar inbuffer[4096];
1306 uschar responsebuffer[4096];
1307
1308 inblock.buffer = inbuffer;
1309 inblock.buffersize = sizeof(inbuffer);
1310 inblock.ptr = inbuffer;
1311 inblock.ptrend = inbuffer;
1312 inblock.sock = fd;
1313 /* this relies on (inblock.sock == tls_out.active) */
1314 if(!smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), expect, timeout))
1315 cancel_cutthrough_connection(TRUE, US"target timeout on read");
1316
1317 if(copy)
1318 {
1319 uschar * cp;
1320 *copy = cp = string_copy(responsebuffer);
1321 /* Trim the trailing end of line */
1322 cp += Ustrlen(responsebuffer);
1323 if(cp > *copy && cp[-1] == '\n') *--cp = '\0';
1324 if(cp > *copy && cp[-1] == '\r') *--cp = '\0';
1325 }
1326
1327 return responsebuffer[0];
1328 }
1329
1330
1331 /* Negotiate dataphase with the cutthrough target, returning success boolean */
1332 BOOL
1333 cutthrough_predata(void)
1334 {
1335 if(cutthrough.fd < 0 || cutthrough.callout_hold_only)
1336 return FALSE;
1337
1338 HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP>> DATA\n");
1339 cutthrough_puts(US"DATA\r\n", 6);
1340 cutthrough_flush_send();
1341
1342 /* Assume nothing buffered. If it was it gets ignored. */
1343 return cutthrough_response(cutthrough.fd, '3', NULL, CUTTHROUGH_DATA_TIMEOUT) == '3';
1344 }
1345
1346
1347 /* tctx arg only to match write_chunk() */
1348 static BOOL
1349 cutthrough_write_chunk(transport_ctx * tctx, uschar * s, int len)
1350 {
1351 uschar * s2;
1352 while(s && (s2 = Ustrchr(s, '\n')))
1353 {
1354 if(!cutthrough_puts(s, s2-s) || !cutthrough_put_nl())
1355 return FALSE;
1356 s = s2+1;
1357 }
1358 return TRUE;
1359 }
1360
1361
1362 /* Buffered send of headers. Return success boolean. */
1363 /* Expands newlines to wire format (CR,NL). */
1364 /* Also sends header-terminating blank line. */
1365 BOOL
1366 cutthrough_headers_send(void)
1367 {
1368 transport_ctx tctx;
1369
1370 if(cutthrough.fd < 0 || cutthrough.callout_hold_only)
1371 return FALSE;
1372
1373 /* We share a routine with the mainline transport to handle header add/remove/rewrites,
1374 but having a separate buffered-output function (for now)
1375 */
1376 HDEBUG(D_acl) debug_printf_indent("----------- start cutthrough headers send -----------\n");
1377
1378 tctx.u.fd = cutthrough.fd;
1379 tctx.tblock = cutthrough.addr.transport;
1380 tctx.addr = &cutthrough.addr;
1381 tctx.check_string = US".";
1382 tctx.escape_string = US"..";
1383 /*XXX check under spool_files_wireformat. Might be irrelevant */
1384 tctx.options = topt_use_crlf;
1385
1386 if (!transport_headers_send(&tctx, &cutthrough_write_chunk))
1387 return FALSE;
1388
1389 HDEBUG(D_acl) debug_printf_indent("----------- done cutthrough headers send ------------\n");
1390 return TRUE;
1391 }
1392
1393
1394 static void
1395 close_cutthrough_connection(const uschar * why)
1396 {
1397 int fd = cutthrough.fd;
1398 if(fd >= 0)
1399 {
1400 /* We could be sending this after a bunch of data, but that is ok as
1401 the only way to cancel the transfer in dataphase is to drop the tcp
1402 conn before the final dot.
1403 */
1404 ctblock.ptr = ctbuffer;
1405 HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP>> QUIT\n");
1406 _cutthrough_puts(US"QUIT\r\n", 6); /* avoid recursion */
1407 _cutthrough_flush_send();
1408 cutthrough.fd = -1; /* avoid recursion via read timeout */
1409 cutthrough.nrcpt = 0; /* permit re-cutthrough on subsequent message */
1410
1411 /* Wait a short time for response, and discard it */
1412 cutthrough_response(fd, '2', NULL, 1);
1413
1414 #ifdef SUPPORT_TLS
1415 tls_close(FALSE, TLS_SHUTDOWN_NOWAIT);
1416 #endif
1417 HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP(close)>>\n");
1418 (void)close(fd);
1419 HDEBUG(D_acl) debug_printf_indent("----------- cutthrough shutdown (%s) ------------\n", why);
1420 }
1421 ctblock.ptr = ctbuffer;
1422 }
1423
1424 void
1425 cancel_cutthrough_connection(BOOL close_noncutthrough_verifies, const uschar * why)
1426 {
1427 if (cutthrough.delivery || close_noncutthrough_verifies)
1428 close_cutthrough_connection(why);
1429 cutthrough.delivery = cutthrough.callout_hold_only = FALSE;
1430 }
1431
1432
1433 void
1434 release_cutthrough_connection(const uschar * why)
1435 {
1436 if (cutthrough.fd < 0) return;
1437 HDEBUG(D_acl) debug_printf_indent("release cutthrough conn: %s\n", why);
1438 cutthrough.fd = -1;
1439 cutthrough.delivery = cutthrough.callout_hold_only = FALSE;
1440 }
1441
1442
1443
1444
1445 /* Have senders final-dot. Send one to cutthrough target, and grab the response.
1446 Log an OK response as a transmission.
1447 Close the connection.
1448 Return smtp response-class digit.
1449 */
1450 uschar *
1451 cutthrough_finaldot(void)
1452 {
1453 uschar res;
1454 address_item * addr;
1455 HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP>> .\n");
1456
1457 /* Assume data finshed with new-line */
1458 if( !cutthrough_puts(US".", 1)
1459 || !cutthrough_put_nl()
1460 || !cutthrough_flush_send()
1461 )
1462 return cutthrough.addr.message;
1463
1464 res = cutthrough_response(cutthrough.fd, '2', &cutthrough.addr.message, CUTTHROUGH_DATA_TIMEOUT);
1465 for (addr = &cutthrough.addr; addr; addr = addr->next)
1466 {
1467 addr->message = cutthrough.addr.message;
1468 switch(res)
1469 {
1470 case '2':
1471 delivery_log(LOG_MAIN, addr, (int)'>', NULL);
1472 close_cutthrough_connection(US"delivered");
1473 break;
1474
1475 case '4':
1476 delivery_log(LOG_MAIN, addr, 0,
1477 US"tmp-reject from cutthrough after DATA:");
1478 break;
1479
1480 case '5':
1481 delivery_log(LOG_MAIN|LOG_REJECT, addr, 0,
1482 US"rejected after DATA:");
1483 break;
1484
1485 default:
1486 break;
1487 }
1488 }
1489 return cutthrough.addr.message;
1490 }
1491
1492
1493
1494 /*************************************************
1495 * Copy error to toplevel address *
1496 *************************************************/
1497
1498 /* This function is used when a verify fails or defers, to ensure that the
1499 failure or defer information is in the original toplevel address. This applies
1500 when an address is redirected to a single new address, and the failure or
1501 deferral happens to the child address.
1502
1503 Arguments:
1504 vaddr the verify address item
1505 addr the final address item
1506 yield FAIL or DEFER
1507
1508 Returns: the value of YIELD
1509 */
1510
1511 static int
1512 copy_error(address_item *vaddr, address_item *addr, int yield)
1513 {
1514 if (addr != vaddr)
1515 {
1516 vaddr->message = addr->message;
1517 vaddr->user_message = addr->user_message;
1518 vaddr->basic_errno = addr->basic_errno;
1519 vaddr->more_errno = addr->more_errno;
1520 vaddr->prop.address_data = addr->prop.address_data;
1521 copyflag(vaddr, addr, af_pass_message);
1522 }
1523 return yield;
1524 }
1525
1526
1527
1528
1529 /**************************************************
1530 * printf that automatically handles TLS if needed *
1531 ***************************************************/
1532
1533 /* This function is used by verify_address() as a substitute for all fprintf()
1534 calls; a direct fprintf() will not produce output in a TLS SMTP session, such
1535 as a response to an EXPN command. smtp_in.c makes smtp_printf available but
1536 that assumes that we always use the smtp_out FILE* when not using TLS or the
1537 ssl buffer when we are. Instead we take a FILE* parameter and check to see if
1538 that is smtp_out; if so, smtp_printf() with TLS support, otherwise regular
1539 fprintf().
1540
1541 Arguments:
1542 f the candidate FILE* to write to
1543 format format string
1544 ... optional arguments
1545
1546 Returns:
1547 nothing
1548 */
1549
1550 static void PRINTF_FUNCTION(2,3)
1551 respond_printf(FILE *f, const char *format, ...)
1552 {
1553 va_list ap;
1554
1555 va_start(ap, format);
1556 if (smtp_out && (f == smtp_out))
1557 smtp_vprintf(format, FALSE, ap);
1558 else
1559 vfprintf(f, format, ap);
1560 va_end(ap);
1561 }
1562
1563
1564
1565 /*************************************************
1566 * Verify an email address *
1567 *************************************************/
1568
1569 /* This function is used both for verification (-bv and at other times) and
1570 address testing (-bt), which is indicated by address_test_mode being set.
1571
1572 Arguments:
1573 vaddr contains the address to verify; the next field in this block
1574 must be NULL
1575 f if not NULL, write the result to this file
1576 options various option bits:
1577 vopt_fake_sender => this sender verify is not for the real
1578 sender (it was verify=sender=xxxx or an address from a
1579 header line) - rewriting must not change sender_address
1580 vopt_is_recipient => this is a recipient address, otherwise
1581 it's a sender address - this affects qualification and
1582 rewriting and messages from callouts
1583 vopt_qualify => qualify an unqualified address; else error
1584 vopt_expn => called from SMTP EXPN command
1585 vopt_success_on_redirect => when a new address is generated
1586 the verification instantly succeeds
1587
1588 These ones are used by do_callout() -- the options variable
1589 is passed to it.
1590
1591 vopt_callout_fullpm => if postmaster check, do full one
1592 vopt_callout_no_cache => don't use callout cache
1593 vopt_callout_random => do the "random" thing
1594 vopt_callout_recipsender => use real sender for recipient
1595 vopt_callout_recippmaster => use postmaster for recipient
1596
1597 callout if > 0, specifies that callout is required, and gives timeout
1598 for individual commands
1599 callout_overall if > 0, gives overall timeout for the callout function;
1600 if < 0, a default is used (see do_callout())
1601 callout_connect the connection timeout for callouts
1602 se_mailfrom when callout is requested to verify a sender, use this
1603 in MAIL FROM; NULL => ""
1604 pm_mailfrom when callout is requested, if non-NULL, do the postmaster
1605 thing and use this as the sender address (may be "")
1606
1607 routed if not NULL, set TRUE if routing succeeded, so we can
1608 distinguish between routing failed and callout failed
1609
1610 Returns: OK address verified
1611 FAIL address failed to verify
1612 DEFER can't tell at present
1613 */
1614
1615 int
1616 verify_address(address_item *vaddr, FILE *f, int options, int callout,
1617 int callout_overall, int callout_connect, uschar *se_mailfrom,
1618 uschar *pm_mailfrom, BOOL *routed)
1619 {
1620 BOOL allok = TRUE;
1621 BOOL full_info = (f == NULL)? FALSE : (debug_selector != 0);
1622 BOOL expn = (options & vopt_expn) != 0;
1623 BOOL success_on_redirect = (options & vopt_success_on_redirect) != 0;
1624 int i;
1625 int yield = OK;
1626 int verify_type = expn? v_expn :
1627 address_test_mode? v_none :
1628 options & vopt_is_recipient? v_recipient : v_sender;
1629 address_item *addr_list;
1630 address_item *addr_new = NULL;
1631 address_item *addr_remote = NULL;
1632 address_item *addr_local = NULL;
1633 address_item *addr_succeed = NULL;
1634 uschar **failure_ptr = options & vopt_is_recipient
1635 ? &recipient_verify_failure : &sender_verify_failure;
1636 uschar *ko_prefix, *cr;
1637 uschar *address = vaddr->address;
1638 uschar *save_sender;
1639 uschar null_sender[] = { 0 }; /* Ensure writeable memory */
1640
1641 /* Clear, just in case */
1642
1643 *failure_ptr = NULL;
1644
1645 /* Set up a prefix and suffix for error message which allow us to use the same
1646 output statements both in EXPN mode (where an SMTP response is needed) and when
1647 debugging with an output file. */
1648
1649 if (expn)
1650 {
1651 ko_prefix = US"553 ";
1652 cr = US"\r";
1653 }
1654 else ko_prefix = cr = US"";
1655
1656 /* Add qualify domain if permitted; otherwise an unqualified address fails. */
1657
1658 if (parse_find_at(address) == NULL)
1659 {
1660 if ((options & vopt_qualify) == 0)
1661 {
1662 if (f != NULL)
1663 respond_printf(f, "%sA domain is required for \"%s\"%s\n",
1664 ko_prefix, address, cr);
1665 *failure_ptr = US"qualify";
1666 return FAIL;
1667 }
1668 address = rewrite_address_qualify(address, options & vopt_is_recipient);
1669 }
1670
1671 DEBUG(D_verify)
1672 {
1673 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1674 debug_printf("%s %s\n", address_test_mode? "Testing" : "Verifying", address);
1675 }
1676
1677 /* Rewrite and report on it. Clear the domain and local part caches - these
1678 may have been set by domains and local part tests during an ACL. */
1679
1680 if (global_rewrite_rules != NULL)
1681 {
1682 uschar *old = address;
1683 address = rewrite_address(address, options & vopt_is_recipient, FALSE,
1684 global_rewrite_rules, rewrite_existflags);
1685 if (address != old)
1686 {
1687 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->localpart_cache[i] = 0;
1688 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->domain_cache[i] = 0;
1689 if (f != NULL && !expn) fprintf(f, "Address rewritten as: %s\n", address);
1690 }
1691 }
1692
1693 /* If this is the real sender address, we must update sender_address at
1694 this point, because it may be referred to in the routers. */
1695
1696 if ((options & (vopt_fake_sender|vopt_is_recipient)) == 0)
1697 sender_address = address;
1698
1699 /* If the address was rewritten to <> no verification can be done, and we have
1700 to return OK. This rewriting is permitted only for sender addresses; for other
1701 addresses, such rewriting fails. */
1702
1703 if (address[0] == 0) return OK;
1704
1705 /* Flip the legacy TLS-related variables over to the outbound set in case
1706 they're used in the context of a transport used by verification. Reset them
1707 at exit from this routine (so no returns allowed from here on). */
1708
1709 tls_modify_variables(&tls_out);
1710
1711 /* Save a copy of the sender address for re-instating if we change it to <>
1712 while verifying a sender address (a nice bit of self-reference there). */
1713
1714 save_sender = sender_address;
1715
1716 /* Observability variable for router/transport use */
1717
1718 verify_mode = options & vopt_is_recipient ? US"R" : US"S";
1719
1720 /* Update the address structure with the possibly qualified and rewritten
1721 address. Set it up as the starting address on the chain of new addresses. */
1722
1723 vaddr->address = address;
1724 addr_new = vaddr;
1725
1726 /* We need a loop, because an address can generate new addresses. We must also
1727 cope with generated pipes and files at the top level. (See also the code and
1728 comment in deliver.c.) However, it is usually the case that the router for
1729 user's .forward files has its verify flag turned off.
1730
1731 If an address generates more than one child, the loop is used only when
1732 full_info is set, and this can only be set locally. Remote enquiries just get
1733 information about the top level address, not anything that it generated. */
1734
1735 while (addr_new)
1736 {
1737 int rc;
1738 address_item *addr = addr_new;
1739
1740 addr_new = addr->next;
1741 addr->next = NULL;
1742
1743 DEBUG(D_verify)
1744 {
1745 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1746 debug_printf("Considering %s\n", addr->address);
1747 }
1748
1749 /* Handle generated pipe, file or reply addresses. We don't get these
1750 when handling EXPN, as it does only one level of expansion. */
1751
1752 if (testflag(addr, af_pfr))
1753 {
1754 allok = FALSE;
1755 if (f != NULL)
1756 {
1757 BOOL allow;
1758
1759 if (addr->address[0] == '>')
1760 {
1761 allow = testflag(addr, af_allow_reply);
1762 fprintf(f, "%s -> mail %s", addr->parent->address, addr->address + 1);
1763 }
1764 else
1765 {
1766 allow = (addr->address[0] == '|')?
1767 testflag(addr, af_allow_pipe) : testflag(addr, af_allow_file);
1768 fprintf(f, "%s -> %s", addr->parent->address, addr->address);
1769 }
1770
1771 if (addr->basic_errno == ERRNO_BADTRANSPORT)
1772 fprintf(f, "\n*** Error in setting up pipe, file, or autoreply:\n"
1773 "%s\n", addr->message);
1774 else if (allow)
1775 fprintf(f, "\n transport = %s\n", addr->transport->name);
1776 else
1777 fprintf(f, " *** forbidden ***\n");
1778 }
1779 continue;
1780 }
1781
1782 /* Just in case some router parameter refers to it. */
1783
1784 return_path = addr->prop.errors_address
1785 ? addr->prop.errors_address : sender_address;
1786
1787 /* Split the address into domain and local part, handling the %-hack if
1788 necessary, and then route it. While routing a sender address, set
1789 $sender_address to <> because that is what it will be if we were trying to
1790 send a bounce to the sender. */
1791
1792 if (routed) *routed = FALSE;
1793 if ((rc = deliver_split_address(addr)) == OK)
1794 {
1795 if (!(options & vopt_is_recipient)) sender_address = null_sender;
1796 rc = route_address(addr, &addr_local, &addr_remote, &addr_new,
1797 &addr_succeed, verify_type);
1798 sender_address = save_sender; /* Put back the real sender */
1799 }
1800
1801 /* If routing an address succeeded, set the flag that remembers, for use when
1802 an ACL cached a sender verify (in case a callout fails). Then if routing set
1803 up a list of hosts or the transport has a host list, and the callout option
1804 is set, and we aren't in a host checking run, do the callout verification,
1805 and set another flag that notes that a callout happened. */
1806
1807 if (rc == OK)
1808 {
1809 if (routed) *routed = TRUE;
1810 if (callout > 0)
1811 {
1812 transport_instance * tp;
1813 host_item * host_list = addr->host_list;
1814
1815 /* Make up some data for use in the case where there is no remote
1816 transport. */
1817
1818 transport_feedback tf = {
1819 .interface = NULL, /* interface (=> any) */
1820 .port = US"smtp",
1821 .protocol = US"smtp",
1822 .hosts = NULL,
1823 .helo_data = US"$smtp_active_hostname",
1824 .hosts_override = FALSE,
1825 .hosts_randomize = FALSE,
1826 .gethostbyname = FALSE,
1827 .qualify_single = TRUE,
1828 .search_parents = FALSE
1829 };
1830
1831 /* If verification yielded a remote transport, we want to use that
1832 transport's options, so as to mimic what would happen if we were really
1833 sending a message to this address. */
1834
1835 if ((tp = addr->transport) && !tp->info->local)
1836 {
1837 (void)(tp->setup)(tp, addr, &tf, 0, 0, NULL);
1838
1839 /* If the transport has hosts and the router does not, or if the
1840 transport is configured to override the router's hosts, we must build a
1841 host list of the transport's hosts, and find the IP addresses */
1842
1843 if (tf.hosts && (!host_list || tf.hosts_override))
1844 {
1845 uschar *s;
1846 const uschar *save_deliver_domain = deliver_domain;
1847 uschar *save_deliver_localpart = deliver_localpart;
1848
1849 host_list = NULL; /* Ignore the router's hosts */
1850
1851 deliver_domain = addr->domain;
1852 deliver_localpart = addr->local_part;
1853 s = expand_string(tf.hosts);
1854 deliver_domain = save_deliver_domain;
1855 deliver_localpart = save_deliver_localpart;
1856
1857 if (!s)
1858 {
1859 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand list of hosts "
1860 "\"%s\" in %s transport for callout: %s", tf.hosts,
1861 tp->name, expand_string_message);
1862 }
1863 else
1864 {
1865 int flags;
1866 host_item *host, *nexthost;
1867 host_build_hostlist(&host_list, s, tf.hosts_randomize);
1868
1869 /* Just ignore failures to find a host address. If we don't manage
1870 to find any addresses, the callout will defer. Note that more than
1871 one address may be found for a single host, which will result in
1872 additional host items being inserted into the chain. Hence we must
1873 save the next host first. */
1874
1875 flags = HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
1876 if (tf.qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
1877 if (tf.search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
1878
1879 for (host = host_list; host; host = nexthost)
1880 {
1881 nexthost = host->next;
1882 if (tf.gethostbyname ||
1883 string_is_ip_address(host->name, NULL) != 0)
1884 (void)host_find_byname(host, NULL, flags, NULL, TRUE);
1885 else
1886 {
1887 dnssec_domains * dnssec_domains = NULL;
1888 if (Ustrcmp(tp->driver_name, "smtp") == 0)
1889 {
1890 smtp_transport_options_block * ob =
1891 (smtp_transport_options_block *) tp->options_block;
1892 dnssec_domains = &ob->dnssec;
1893 }
1894
1895 (void) host_find_bydns(host, NULL, flags, NULL, NULL, NULL,
1896 dnssec_domains, NULL, NULL);
1897 }
1898 }
1899 }
1900 }
1901 }
1902
1903 /* Can only do a callout if we have at least one host! If the callout
1904 fails, it will have set ${sender,recipient}_verify_failure. */
1905
1906 if (host_list)
1907 {
1908 HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n");
1909 if (host_checking && !host_checking_callout)
1910 {
1911 HDEBUG(D_verify)
1912 debug_printf("... callout omitted by default when host testing\n"
1913 "(Use -bhc if you want the callouts to happen.)\n");
1914 }
1915 else
1916 {
1917 #ifdef SUPPORT_TLS
1918 deliver_set_expansions(addr);
1919 #endif
1920 rc = do_callout(addr, host_list, &tf, callout, callout_overall,
1921 callout_connect, options, se_mailfrom, pm_mailfrom);
1922 }
1923 }
1924 else
1925 {
1926 HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor "
1927 "transport provided a host list\n");
1928 }
1929 }
1930 }
1931
1932 /* Otherwise, any failure is a routing failure */
1933
1934 else *failure_ptr = US"route";
1935
1936 /* A router may return REROUTED if it has set up a child address as a result
1937 of a change of domain name (typically from widening). In this case we always
1938 want to continue to verify the new child. */
1939
1940 if (rc == REROUTED) continue;
1941
1942 /* Handle hard failures */
1943
1944 if (rc == FAIL)
1945 {
1946 allok = FALSE;
1947 if (f)
1948 {
1949 address_item *p = addr->parent;
1950
1951 respond_printf(f, "%s%s %s", ko_prefix,
1952 full_info ? addr->address : address,
1953 address_test_mode ? "is undeliverable" : "failed to verify");
1954 if (!expn && admin_user)
1955 {
1956 if (addr->basic_errno > 0)
1957 respond_printf(f, ": %s", strerror(addr->basic_errno));
1958 if (addr->message)
1959 respond_printf(f, ": %s", addr->message);
1960 }
1961
1962 /* Show parents iff doing full info */
1963
1964 if (full_info) while (p)
1965 {
1966 respond_printf(f, "%s\n <-- %s", cr, p->address);
1967 p = p->parent;
1968 }
1969 respond_printf(f, "%s\n", cr);
1970 }
1971 cancel_cutthrough_connection(TRUE, US"routing hard fail");
1972
1973 if (!full_info)
1974 {
1975 yield = copy_error(vaddr, addr, FAIL);
1976 goto out;
1977 }
1978 yield = FAIL;
1979 }
1980
1981 /* Soft failure */
1982
1983 else if (rc == DEFER)
1984 {
1985 allok = FALSE;
1986 if (f)
1987 {
1988 address_item *p = addr->parent;
1989 respond_printf(f, "%s%s cannot be resolved at this time", ko_prefix,
1990 full_info? addr->address : address);
1991 if (!expn && admin_user)
1992 {
1993 if (addr->basic_errno > 0)
1994 respond_printf(f, ": %s", strerror(addr->basic_errno));
1995 if (addr->message)
1996 respond_printf(f, ": %s", addr->message);
1997 else if (addr->basic_errno <= 0)
1998 respond_printf(f, ": unknown error");
1999 }
2000
2001 /* Show parents iff doing full info */
2002
2003 if (full_info) while (p)
2004 {
2005 respond_printf(f, "%s\n <-- %s", cr, p->address);
2006 p = p->parent;
2007 }
2008 respond_printf(f, "%s\n", cr);
2009 }
2010 cancel_cutthrough_connection(TRUE, US"routing soft fail");
2011
2012 if (!full_info)
2013 {
2014 yield = copy_error(vaddr, addr, DEFER);
2015 goto out;
2016 }
2017 if (yield == OK) yield = DEFER;
2018 }
2019
2020 /* If we are handling EXPN, we do not want to continue to route beyond
2021 the top level (whose address is in "address"). */
2022
2023 else if (expn)
2024 {
2025 uschar *ok_prefix = US"250-";
2026
2027 if (!addr_new)
2028 if (!addr_local && !addr_remote)
2029 respond_printf(f, "250 mail to <%s> is discarded\r\n", address);
2030 else
2031 respond_printf(f, "250 <%s>\r\n", address);
2032
2033 else do
2034 {
2035 address_item *addr2 = addr_new;
2036 addr_new = addr2->next;
2037 if (!addr_new) ok_prefix = US"250 ";
2038 respond_printf(f, "%s<%s>\r\n", ok_prefix, addr2->address);
2039 } while (addr_new);
2040 yield = OK;
2041 goto out;
2042 }
2043
2044 /* Successful routing other than EXPN. */
2045
2046 else
2047 {
2048 /* Handle successful routing when short info wanted. Otherwise continue for
2049 other (generated) addresses. Short info is the operational case. Full info
2050 can be requested only when debug_selector != 0 and a file is supplied.
2051
2052 There is a conflict between the use of aliasing as an alternate email
2053 address, and as a sort of mailing list. If an alias turns the incoming
2054 address into just one address (e.g. J.Caesar->jc44) you may well want to
2055 carry on verifying the generated address to ensure it is valid when
2056 checking incoming mail. If aliasing generates multiple addresses, you
2057 probably don't want to do this. Exim therefore treats the generation of
2058 just a single new address as a special case, and continues on to verify the
2059 generated address. */
2060
2061 if ( !full_info /* Stop if short info wanted AND */
2062 && ( ( !addr_new /* No new address OR */
2063 || addr_new->next /* More than one new address OR */
2064 || testflag(addr_new, af_pfr) /* New address is pfr */
2065 )
2066 || /* OR */
2067 ( addr_new /* At least one new address AND */
2068 && success_on_redirect /* success_on_redirect is set */
2069 ) )
2070 )
2071 {
2072 if (f) fprintf(f, "%s %s\n",
2073 address, address_test_mode ? "is deliverable" : "verified");
2074
2075 /* If we have carried on to verify a child address, we want the value
2076 of $address_data to be that of the child */
2077
2078 vaddr->prop.address_data = addr->prop.address_data;
2079
2080 /* If stopped because more than one new address, cannot cutthrough */
2081
2082 if (addr_new && addr_new->next)
2083 cancel_cutthrough_connection(TRUE, US"multiple addresses from routing");
2084
2085 yield = OK;
2086 goto out;
2087 }
2088 }
2089 } /* Loop for generated addresses */
2090
2091 /* Display the full results of the successful routing, including any generated
2092 addresses. Control gets here only when full_info is set, which requires f not
2093 to be NULL, and this occurs only when a top-level verify is called with the
2094 debugging switch on.
2095
2096 If there are no local and no remote addresses, and there were no pipes, files,
2097 or autoreplies, and there were no errors or deferments, the message is to be
2098 discarded, usually because of the use of :blackhole: in an alias file. */
2099
2100 if (allok && !addr_local && !addr_remote)
2101 {
2102 fprintf(f, "mail to %s is discarded\n", address);
2103 goto out;
2104 }
2105
2106 for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++)
2107 while (addr_list)
2108 {
2109 address_item *addr = addr_list;
2110 address_item *p = addr->parent;
2111 transport_instance * tp = addr->transport;
2112
2113 addr_list = addr->next;
2114
2115 fprintf(f, "%s", CS addr->address);
2116 #ifdef EXPERIMENTAL_SRS
2117 if(addr->prop.srs_sender)
2118 fprintf(f, " [srs = %s]", addr->prop.srs_sender);
2119 #endif
2120
2121 /* If the address is a duplicate, show something about it. */
2122
2123 if (!testflag(addr, af_pfr))
2124 {
2125 tree_node *tnode;
2126 if ((tnode = tree_search(tree_duplicates, addr->unique)))
2127 fprintf(f, " [duplicate, would not be delivered]");
2128 else tree_add_duplicate(addr->unique, addr);
2129 }
2130
2131 /* Now show its parents */
2132
2133 for (p = addr->parent; p; p = p->parent)
2134 fprintf(f, "\n <-- %s", p->address);
2135 fprintf(f, "\n ");
2136
2137 /* Show router, and transport */
2138
2139 fprintf(f, "router = %s, transport = %s\n",
2140 addr->router->name, tp ? tp->name : US"unset");
2141
2142 /* Show any hosts that are set up by a router unless the transport
2143 is going to override them; fiddle a bit to get a nice format. */
2144
2145 if (addr->host_list && tp && !tp->overrides_hosts)
2146 {
2147 host_item *h;
2148 int maxlen = 0;
2149 int maxaddlen = 0;
2150 for (h = addr->host_list; h; h = h->next)
2151 { /* get max lengths of host names, addrs */
2152 int len = Ustrlen(h->name);
2153 if (len > maxlen) maxlen = len;
2154 len = h->address ? Ustrlen(h->address) : 7;
2155 if (len > maxaddlen) maxaddlen = len;
2156 }
2157 for (h = addr->host_list; h; h = h->next)
2158 {
2159 fprintf(f, " host %-*s ", maxlen, h->name);
2160
2161 if (h->address)
2162 fprintf(f, "[%s%-*c", h->address, maxaddlen+1 - Ustrlen(h->address), ']');
2163 else if (tp->info->local)
2164 fprintf(f, " %-*s ", maxaddlen, ""); /* Omit [unknown] for local */
2165 else
2166 fprintf(f, "[%s%-*c", "unknown", maxaddlen+1 - 7, ']');
2167
2168 if (h->mx >= 0) fprintf(f, " MX=%d", h->mx);
2169 if (h->port != PORT_NONE) fprintf(f, " port=%d", h->port);
2170 if (running_in_test_harness && h->dnssec == DS_YES) fputs(" AD", f);
2171 if (h->status == hstatus_unusable) fputs(" ** unusable **", f);
2172 fputc('\n', f);
2173 }
2174 }
2175 }
2176
2177 /* Yield will be DEFER or FAIL if any one address has, only for full_info (which is
2178 the -bv or -bt case). */
2179
2180 out:
2181 verify_mode = NULL;
2182 tls_modify_variables(&tls_in);
2183
2184 return yield;
2185 }
2186
2187
2188
2189
2190 /*************************************************
2191 * Check headers for syntax errors *
2192 *************************************************/
2193
2194 /* This function checks those header lines that contain addresses, and verifies
2195 that all the addresses therein are 5322-syntactially correct.
2196
2197 Arguments:
2198 msgptr where to put an error message
2199
2200 Returns: OK
2201 FAIL
2202 */
2203
2204 int
2205 verify_check_headers(uschar **msgptr)
2206 {
2207 header_line *h;
2208 uschar *colon, *s;
2209 int yield = OK;
2210
2211 for (h = header_list; h && yield == OK; h = h->next)
2212 {
2213 if (h->type != htype_from &&
2214 h->type != htype_reply_to &&
2215 h->type != htype_sender &&
2216 h->type != htype_to &&
2217 h->type != htype_cc &&
2218 h->type != htype_bcc)
2219 continue;
2220
2221 colon = Ustrchr(h->text, ':');
2222 s = colon + 1;
2223 while (isspace(*s)) s++;
2224
2225 /* Loop for multiple addresses in the header, enabling group syntax. Note
2226 that we have to reset this after the header has been scanned. */
2227
2228 parse_allow_group = TRUE;
2229
2230 while (*s)
2231 {
2232 uschar *ss = parse_find_address_end(s, FALSE);
2233 uschar *recipient, *errmess;
2234 int terminator = *ss;
2235 int start, end, domain;
2236
2237 /* Temporarily terminate the string at this point, and extract the
2238 operative address within, allowing group syntax. */
2239
2240 *ss = 0;
2241 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2242 *ss = terminator;
2243
2244 /* Permit an unqualified address only if the message is local, or if the
2245 sending host is configured to be permitted to send them. */
2246
2247 if (recipient && !domain)
2248 {
2249 if (h->type == htype_from || h->type == htype_sender)
2250 {
2251 if (!allow_unqualified_sender) recipient = NULL;
2252 }
2253 else
2254 {
2255 if (!allow_unqualified_recipient) recipient = NULL;
2256 }
2257 if (recipient == NULL) errmess = US"unqualified address not permitted";
2258 }
2259
2260 /* It's an error if no address could be extracted, except for the special
2261 case of an empty address. */
2262
2263 if (!recipient && Ustrcmp(errmess, "empty address") != 0)
2264 {
2265 uschar *verb = US"is";
2266 uschar *t = ss;
2267 uschar *tt = colon;
2268 int len;
2269
2270 /* Arrange not to include any white space at the end in the
2271 error message or the header name. */
2272
2273 while (t > s && isspace(t[-1])) t--;
2274 while (tt > h->text && isspace(tt[-1])) tt--;
2275
2276 /* Add the address that failed to the error message, since in a
2277 header with very many addresses it is sometimes hard to spot
2278 which one is at fault. However, limit the amount of address to
2279 quote - cases have been seen where, for example, a missing double
2280 quote in a humungous To: header creates an "address" that is longer
2281 than string_sprintf can handle. */
2282
2283 len = t - s;
2284 if (len > 1024)
2285 {
2286 len = 1024;
2287 verb = US"begins";
2288 }
2289
2290 /* deconst cast ok as we're passing a non-const to string_printing() */
2291 *msgptr = US string_printing(
2292 string_sprintf("%s: failing address in \"%.*s:\" header %s: %.*s",
2293 errmess, (int)(tt - h->text), h->text, verb, len, s));
2294
2295 yield = FAIL;
2296 break; /* Out of address loop */
2297 }
2298
2299 /* Advance to the next address */
2300
2301 s = ss + (terminator ? 1 : 0);
2302 while (isspace(*s)) s++;
2303 } /* Next address */
2304
2305 parse_allow_group = FALSE;
2306 parse_found_group = FALSE;
2307 } /* Next header unless yield has been set FALSE */
2308
2309 return yield;
2310 }
2311
2312
2313 /*************************************************
2314 * Check header names for 8-bit characters *
2315 *************************************************/
2316
2317 /* This function checks for invalid characters in header names. See
2318 RFC 5322, 2.2. and RFC 6532, 3.
2319
2320 Arguments:
2321 msgptr where to put an error message
2322
2323 Returns: OK
2324 FAIL
2325 */
2326
2327 int
2328 verify_check_header_names_ascii(uschar **msgptr)
2329 {
2330 header_line *h;
2331 uschar *colon, *s;
2332
2333 for (h = header_list; h; h = h->next)
2334 {
2335 colon = Ustrchr(h->text, ':');
2336 for(s = h->text; s < colon; s++)
2337 if ((*s < 33) || (*s > 126))
2338 {
2339 *msgptr = string_sprintf("Invalid character in header \"%.*s\" found",
2340 colon - h->text, h->text);
2341 return FAIL;
2342 }
2343 }
2344 return OK;
2345 }
2346
2347 /*************************************************
2348 * Check for blind recipients *
2349 *************************************************/
2350
2351 /* This function checks that every (envelope) recipient is mentioned in either
2352 the To: or Cc: header lines, thus detecting blind carbon copies.
2353
2354 There are two ways of scanning that could be used: either scan the header lines
2355 and tick off the recipients, or scan the recipients and check the header lines.
2356 The original proposed patch did the former, but I have chosen to do the latter,
2357 because (a) it requires no memory and (b) will use fewer resources when there
2358 are many addresses in To: and/or Cc: and only one or two envelope recipients.
2359
2360 Arguments: none
2361 Returns: OK if there are no blind recipients
2362 FAIL if there is at least one blind recipient
2363 */
2364
2365 int
2366 verify_check_notblind(void)
2367 {
2368 int i;
2369 for (i = 0; i < recipients_count; i++)
2370 {
2371 header_line *h;
2372 BOOL found = FALSE;
2373 uschar *address = recipients_list[i].address;
2374
2375 for (h = header_list; !found && h != NULL; h = h->next)
2376 {
2377 uschar *colon, *s;
2378
2379 if (h->type != htype_to && h->type != htype_cc) continue;
2380
2381 colon = Ustrchr(h->text, ':');
2382 s = colon + 1;
2383 while (isspace(*s)) s++;
2384
2385 /* Loop for multiple addresses in the header, enabling group syntax. Note
2386 that we have to reset this after the header has been scanned. */
2387
2388 parse_allow_group = TRUE;
2389
2390 while (*s != 0)
2391 {
2392 uschar *ss = parse_find_address_end(s, FALSE);
2393 uschar *recipient,*errmess;
2394 int terminator = *ss;
2395 int start, end, domain;
2396
2397 /* Temporarily terminate the string at this point, and extract the
2398 operative address within, allowing group syntax. */
2399
2400 *ss = 0;
2401 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2402 *ss = terminator;
2403
2404 /* If we found a valid recipient that has a domain, compare it with the
2405 envelope recipient. Local parts are compared case-sensitively, domains
2406 case-insensitively. By comparing from the start with length "domain", we
2407 include the "@" at the end, which ensures that we are comparing the whole
2408 local part of each address. */
2409
2410 if (recipient != NULL && domain != 0)
2411 {
2412 found = Ustrncmp(recipient, address, domain) == 0 &&
2413 strcmpic(recipient + domain, address + domain) == 0;
2414 if (found) break;
2415 }
2416
2417 /* Advance to the next address */
2418
2419 s = ss + (terminator? 1:0);
2420 while (isspace(*s)) s++;
2421 } /* Next address */
2422
2423 parse_allow_group = FALSE;
2424 parse_found_group = FALSE;
2425 } /* Next header (if found is false) */
2426
2427 if (!found) return FAIL;
2428 } /* Next recipient */
2429
2430 return OK;
2431 }
2432
2433
2434
2435 /*************************************************
2436 * Find if verified sender *
2437 *************************************************/
2438
2439 /* Usually, just a single address is verified as the sender of the message.
2440 However, Exim can be made to verify other addresses as well (often related in
2441 some way), and this is useful in some environments. There may therefore be a
2442 chain of such addresses that have previously been tested. This function finds
2443 whether a given address is on the chain.
2444
2445 Arguments: the address to be verified
2446 Returns: pointer to an address item, or NULL
2447 */
2448
2449 address_item *
2450 verify_checked_sender(uschar *sender)
2451 {
2452 address_item *addr;
2453 for (addr = sender_verified_list; addr != NULL; addr = addr->next)
2454 if (Ustrcmp(sender, addr->address) == 0) break;
2455 return addr;
2456 }
2457
2458
2459
2460
2461
2462 /*************************************************
2463 * Get valid header address *
2464 *************************************************/
2465
2466 /* Scan the originator headers of the message, looking for an address that
2467 verifies successfully. RFC 822 says:
2468
2469 o The "Sender" field mailbox should be sent notices of
2470 any problems in transport or delivery of the original
2471 messages. If there is no "Sender" field, then the
2472 "From" field mailbox should be used.
2473
2474 o If the "Reply-To" field exists, then the reply should
2475 go to the addresses indicated in that field and not to
2476 the address(es) indicated in the "From" field.
2477
2478 So we check a Sender field if there is one, else a Reply_to field, else a From
2479 field. As some strange messages may have more than one of these fields,
2480 especially if they are resent- fields, check all of them if there is more than
2481 one.
2482
2483 Arguments:
2484 user_msgptr points to where to put a user error message
2485 log_msgptr points to where to put a log error message
2486 callout timeout for callout check (passed to verify_address())
2487 callout_overall overall callout timeout (ditto)
2488 callout_connect connect callout timeout (ditto)
2489 se_mailfrom mailfrom for verify; NULL => ""
2490 pm_mailfrom sender for pm callout check (passed to verify_address())
2491 options callout options (passed to verify_address())
2492 verrno where to put the address basic_errno
2493
2494 If log_msgptr is set to something without setting user_msgptr, the caller
2495 normally uses log_msgptr for both things.
2496
2497 Returns: result of the verification attempt: OK, FAIL, or DEFER;
2498 FAIL is given if no appropriate headers are found
2499 */
2500
2501 int
2502 verify_check_header_address(uschar **user_msgptr, uschar **log_msgptr,
2503 int callout, int callout_overall, int callout_connect, uschar *se_mailfrom,
2504 uschar *pm_mailfrom, int options, int *verrno)
2505 {
2506 static int header_types[] = { htype_sender, htype_reply_to, htype_from };
2507 BOOL done = FALSE;
2508 int yield = FAIL;
2509 int i;
2510
2511 for (i = 0; i < 3 && !done; i++)
2512 {
2513 header_line *h;
2514 for (h = header_list; h != NULL && !done; h = h->next)
2515 {
2516 int terminator, new_ok;
2517 uschar *s, *ss, *endname;
2518
2519 if (h->type != header_types[i]) continue;
2520 s = endname = Ustrchr(h->text, ':') + 1;
2521
2522 /* Scan the addresses in the header, enabling group syntax. Note that we
2523 have to reset this after the header has been scanned. */
2524
2525 parse_allow_group = TRUE;
2526
2527 while (*s != 0)
2528 {
2529 address_item *vaddr;
2530
2531 while (isspace(*s) || *s == ',') s++;
2532 if (*s == 0) break; /* End of header */
2533
2534 ss = parse_find_address_end(s, FALSE);
2535
2536 /* The terminator is a comma or end of header, but there may be white
2537 space preceding it (including newline for the last address). Move back
2538 past any white space so we can check against any cached envelope sender
2539 address verifications. */
2540
2541 while (isspace(ss[-1])) ss--;
2542 terminator = *ss;
2543 *ss = 0;
2544
2545 HDEBUG(D_verify) debug_printf("verifying %.*s header address %s\n",
2546 (int)(endname - h->text), h->text, s);
2547
2548 /* See if we have already verified this address as an envelope sender,
2549 and if so, use the previous answer. */
2550
2551 vaddr = verify_checked_sender(s);
2552
2553 if (vaddr != NULL && /* Previously checked */
2554 (callout <= 0 || /* No callout needed; OR */
2555 vaddr->special_action > 256)) /* Callout was done */
2556 {
2557 new_ok = vaddr->special_action & 255;
2558 HDEBUG(D_verify) debug_printf("previously checked as envelope sender\n");
2559 *ss = terminator; /* Restore shortened string */
2560 }
2561
2562 /* Otherwise we run the verification now. We must restore the shortened
2563 string before running the verification, so the headers are correct, in
2564 case there is any rewriting. */
2565
2566 else
2567 {
2568 int start, end, domain;
2569 uschar *address = parse_extract_address(s, log_msgptr, &start, &end,
2570 &domain, FALSE);
2571
2572 *ss = terminator;
2573
2574 /* If we found an empty address, just carry on with the next one, but
2575 kill the message. */
2576
2577 if (address == NULL && Ustrcmp(*log_msgptr, "empty address") == 0)
2578 {
2579 *log_msgptr = NULL;
2580 s = ss;
2581 continue;
2582 }
2583
2584 /* If verification failed because of a syntax error, fail this
2585 function, and ensure that the failing address gets added to the error
2586 message. */
2587
2588 if (address == NULL)
2589 {
2590 new_ok = FAIL;
2591 while (ss > s && isspace(ss[-1])) ss--;
2592 *log_msgptr = string_sprintf("syntax error in '%.*s' header when "
2593 "scanning for sender: %s in \"%.*s\"",
2594 (int)(endname - h->text), h->text, *log_msgptr, (int)(ss - s), s);
2595 yield = FAIL;
2596 done = TRUE;
2597 break;
2598 }
2599
2600 /* Else go ahead with the sender verification. But it isn't *the*
2601 sender of the message, so set vopt_fake_sender to stop sender_address
2602 being replaced after rewriting or qualification. */
2603
2604 else
2605 {
2606 vaddr = deliver_make_addr(address, FALSE);
2607 new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender,
2608 callout, callout_overall, callout_connect, se_mailfrom,
2609 pm_mailfrom, NULL);
2610 }
2611 }
2612
2613 /* We now have the result, either newly found, or cached. If we are
2614 giving out error details, set a specific user error. This means that the
2615 last of these will be returned to the user if all three fail. We do not
2616 set a log message - the generic one below will be used. */
2617
2618 if (new_ok != OK)
2619 {
2620 *verrno = vaddr->basic_errno;
2621 if (smtp_return_error_details)
2622 *user_msgptr = string_sprintf("Rejected after DATA: "
2623 "could not verify \"%.*s\" header address\n%s: %s",
2624 (int)(endname - h->text), h->text, vaddr->address, vaddr->message);
2625 }
2626
2627 /* Success or defer */
2628
2629 if (new_ok == OK)
2630 {
2631 yield = OK;
2632 done = TRUE;
2633 break;
2634 }
2635
2636 if (new_ok == DEFER) yield = DEFER;
2637
2638 /* Move on to any more addresses in the header */
2639
2640 s = ss;
2641 } /* Next address */
2642
2643 parse_allow_group = FALSE;
2644 parse_found_group = FALSE;
2645 } /* Next header, unless done */
2646 } /* Next header type unless done */
2647
2648 if (yield == FAIL && *log_msgptr == NULL)
2649 *log_msgptr = US"there is no valid sender in any header line";
2650
2651 if (yield == DEFER && *log_msgptr == NULL)
2652 *log_msgptr = US"all attempts to verify a sender in a header line deferred";
2653
2654 return yield;
2655 }
2656
2657
2658
2659
2660 /*************************************************
2661 * Get RFC 1413 identification *
2662 *************************************************/
2663
2664 /* Attempt to get an id from the sending machine via the RFC 1413 protocol. If
2665 the timeout is set to zero, then the query is not done. There may also be lists
2666 of hosts and nets which are exempt. To guard against malefactors sending
2667 non-printing characters which could, for example, disrupt a message's headers,
2668 make sure the string consists of printing characters only.
2669
2670 Argument:
2671 port the port to connect to; usually this is IDENT_PORT (113), but when
2672 running in the test harness with -bh a different value is used.
2673
2674 Returns: nothing
2675
2676 Side effect: any received ident value is put in sender_ident (NULL otherwise)
2677 */
2678
2679 void
2680 verify_get_ident(int port)
2681 {
2682 int sock, host_af, qlen;
2683 int received_sender_port, received_interface_port, n;
2684 uschar *p;
2685 blob early_data;
2686 uschar buffer[2048];
2687
2688 /* Default is no ident. Check whether we want to do an ident check for this
2689 host. */
2690
2691 sender_ident = NULL;
2692 if (rfc1413_query_timeout <= 0 || verify_check_host(&rfc1413_hosts) != OK)
2693 return;
2694
2695 DEBUG(D_ident) debug_printf("doing ident callback\n");
2696
2697 /* Set up a connection to the ident port of the remote host. Bind the local end
2698 to the incoming interface address. If the sender host address is an IPv6
2699 address, the incoming interface address will also be IPv6. */
2700
2701 host_af = Ustrchr(sender_host_address, ':') == NULL ? AF_INET : AF_INET6;
2702 if ((sock = ip_socket(SOCK_STREAM, host_af)) < 0) return;
2703
2704 if (ip_bind(sock, host_af, interface_address, 0) < 0)
2705 {
2706 DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n",
2707 strerror(errno));
2708 goto END_OFF;
2709 }
2710
2711 /* Construct and send the query. */
2712
2713 qlen = snprintf(CS buffer, sizeof(buffer), "%d , %d\r\n",
2714 sender_host_port, interface_port);
2715 early_data.data = buffer;
2716 early_data.len = qlen;
2717
2718 if (ip_connect(sock, host_af, sender_host_address, port,
2719 rfc1413_query_timeout, &early_data) < 0)
2720 {
2721 if (errno == ETIMEDOUT && LOGGING(ident_timeout))
2722 log_write(0, LOG_MAIN, "ident connection to %s timed out",
2723 sender_host_address);
2724 else
2725 DEBUG(D_ident) debug_printf("ident connection to %s failed: %s\n",
2726 sender_host_address, strerror(errno));
2727 goto END_OFF;
2728 }
2729
2730 /* Read a response line. We put it into the rest of the buffer, using several
2731 recv() calls if necessary. */
2732
2733 p = buffer + qlen;
2734
2735 for (;;)
2736 {
2737 uschar *pp;
2738 int count;
2739 int size = sizeof(buffer) - (p - buffer);
2740
2741 if (size <= 0) goto END_OFF; /* Buffer filled without seeing \n. */
2742 count = ip_recv(sock, p, size, rfc1413_query_timeout);
2743 if (count <= 0) goto END_OFF; /* Read error or EOF */
2744
2745 /* Scan what we just read, to see if we have reached the terminating \r\n. Be
2746 generous, and accept a plain \n terminator as well. The only illegal
2747 character is 0. */
2748
2749 for (pp = p; pp < p + count; pp++)
2750 {
2751 if (*pp == 0) goto END_OFF; /* Zero octet not allowed */
2752 if (*pp == '\n')
2753 {
2754 if (pp[-1] == '\r') pp--;
2755 *pp = 0;
2756 goto GOT_DATA; /* Break out of both loops */
2757 }
2758 }
2759
2760 /* Reached the end of the data without finding \n. Let the loop continue to
2761 read some more, if there is room. */
2762
2763 p = pp;
2764 }
2765
2766 GOT_DATA:
2767
2768 /* We have received a line of data. Check it carefully. It must start with the
2769 same two port numbers that we sent, followed by data as defined by the RFC. For
2770 example,
2771
2772 12345 , 25 : USERID : UNIX :root
2773
2774 However, the amount of white space may be different to what we sent. In the
2775 "osname" field there may be several sub-fields, comma separated. The data we
2776 actually want to save follows the third colon. Some systems put leading spaces
2777 in it - we discard those. */
2778
2779 if (sscanf(CS buffer + qlen, "%d , %d%n", &received_sender_port,
2780 &received_interface_port, &n) != 2 ||
2781 received_sender_port != sender_host_port ||
2782 received_interface_port != interface_port)
2783 goto END_OFF;
2784
2785 p = buffer + qlen + n;
2786 while(isspace(*p)) p++;
2787 if (*p++ != ':') goto END_OFF;
2788 while(isspace(*p)) p++;
2789 if (Ustrncmp(p, "USERID", 6) != 0) goto END_OFF;
2790 p += 6;
2791 while(isspace(*p)) p++;
2792 if (*p++ != ':') goto END_OFF;
2793 while (*p != 0 && *p != ':') p++;
2794 if (*p++ == 0) goto END_OFF;
2795 while(isspace(*p)) p++;
2796 if (*p == 0) goto END_OFF;
2797
2798 /* The rest of the line is the data we want. We turn it into printing
2799 characters when we save it, so that it cannot mess up the format of any logging
2800 or Received: lines into which it gets inserted. We keep a maximum of 127
2801 characters. The deconst cast is ok as we fed a nonconst to string_printing() */
2802
2803 sender_ident = US string_printing(string_copyn(p, 127));
2804 DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident);
2805
2806 END_OFF:
2807 (void)close(sock);
2808 return;
2809 }
2810
2811
2812
2813
2814 /*************************************************
2815 * Match host to a single host-list item *
2816 *************************************************/
2817
2818 /* This function compares a host (name or address) against a single item
2819 from a host list. The host name gets looked up if it is needed and is not
2820 already known. The function is called from verify_check_this_host() via
2821 match_check_list(), which is why most of its arguments are in a single block.
2822
2823 Arguments:
2824 arg the argument block (see below)
2825 ss the host-list item
2826 valueptr where to pass back looked up data, or NULL
2827 error for error message when returning ERROR
2828
2829 The block contains:
2830 host_name (a) the host name, or
2831 (b) NULL, implying use sender_host_name and
2832 sender_host_aliases, looking them up if required, or
2833 (c) the empty string, meaning that only IP address matches
2834 are permitted
2835 host_address the host address
2836 host_ipv4 the IPv4 address taken from an IPv6 one
2837
2838 Returns: OK matched
2839 FAIL did not match
2840 DEFER lookup deferred
2841 ERROR (a) failed to find the host name or IP address, or
2842 (b) unknown lookup type specified, or
2843 (c) host name encountered when only IP addresses are
2844 being matched
2845 */
2846
2847 int
2848 check_host(void *arg, const uschar *ss, const uschar **valueptr, uschar **error)
2849 {
2850 check_host_block *cb = (check_host_block *)arg;
2851 int mlen = -1;
2852 int maskoffset;
2853 BOOL iplookup = FALSE;
2854 BOOL isquery = FALSE;
2855 BOOL isiponly = cb->host_name != NULL && cb->host_name[0] == 0;
2856 const uschar *t;
2857 uschar *semicolon;
2858 uschar **aliases;
2859
2860 /* Optimize for the special case when the pattern is "*". */
2861
2862 if (*ss == '*' && ss[1] == 0) return OK;
2863
2864 /* If the pattern is empty, it matches only in the case when there is no host -
2865 this can occur in ACL checking for SMTP input using the -bs option. In this
2866 situation, the host address is the empty string. */
2867
2868 if (cb->host_address[0] == 0) return (*ss == 0)? OK : FAIL;
2869 if (*ss == 0) return FAIL;
2870
2871 /* If the pattern is precisely "@" then match against the primary host name,
2872 provided that host name matching is permitted; if it's "@[]" match against the
2873 local host's IP addresses. */
2874
2875 if (*ss == '@')
2876 {
2877 if (ss[1] == 0)
2878 {
2879 if (isiponly) return ERROR;
2880 ss = primary_hostname;
2881 }
2882 else if (Ustrcmp(ss, "@[]") == 0)
2883 {
2884 ip_address_item *ip;
2885 for (ip = host_find_interfaces(); ip != NULL; ip = ip->next)
2886 if (Ustrcmp(ip->address, cb->host_address) == 0) return OK;
2887 return FAIL;
2888 }
2889 }
2890
2891 /* If the pattern is an IP address, optionally followed by a bitmask count, do
2892 a (possibly masked) comparison with the current IP address. */
2893
2894 if (string_is_ip_address(ss, &maskoffset) != 0)
2895 return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL);
2896
2897 /* The pattern is not an IP address. A common error that people make is to omit
2898 one component of an IPv4 address, either by accident, or believing that, for
2899 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,
2900 which it isn't. (Those applications that do accept 1.2.3 as an IP address
2901 interpret it as 1.2.0.3 because the final component becomes 16-bit - this is an
2902 ancient specification.) To aid in debugging these cases, we give a specific
2903 error if the pattern contains only digits and dots or contains a slash preceded
2904 only by digits and dots (a slash at the start indicates a file name and of
2905 course slashes may be present in lookups, but not preceded only by digits and
2906 dots). */
2907
2908 for (t = ss; isdigit(*t) || *t == '.'; t++);
2909 if (*t == 0 || (*t == '/' && t != ss))
2910 {
2911 *error = US"malformed IPv4 address or address mask";
2912 return ERROR;
2913 }
2914
2915 /* See if there is a semicolon in the pattern */
2916
2917 semicolon = Ustrchr(ss, ';');
2918
2919 /* If we are doing an IP address only match, then all lookups must be IP
2920 address lookups, even if there is no "net-". */
2921
2922 if (isiponly)
2923 {
2924 iplookup = semicolon != NULL;
2925 }
2926
2927 /* Otherwise, if the item is of the form net[n]-lookup;<file|query> then it is
2928 a lookup on a masked IP network, in textual form. We obey this code even if we
2929 have already set iplookup, so as to skip over the "net-" prefix and to set the
2930 mask length. The net- stuff really only applies to single-key lookups where the
2931 key is implicit. For query-style lookups the key is specified in the query.
2932 From release 4.30, the use of net- for query style is no longer needed, but we
2933 retain it for backward compatibility. */
2934
2935 if (Ustrncmp(ss, "net", 3) == 0 && semicolon != NULL)
2936 {
2937 mlen = 0;
2938 for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0';
2939 if (mlen == 0 && t == ss+3) mlen = -1; /* No mask supplied */
2940 iplookup = (*t++ == '-');
2941 }
2942 else t = ss;
2943
2944 /* Do the IP address lookup if that is indeed what we have */
2945
2946 if (iplookup)
2947 {
2948 int insize;
2949 int search_type;
2950 int incoming[4];
2951 void *handle;
2952 uschar *filename, *key, *result;
2953 uschar buffer[64];
2954
2955 /* Find the search type */
2956
2957 search_type = search_findtype(t, semicolon - t);
2958
2959 if (search_type < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
2960 search_error_message);
2961
2962 /* Adjust parameters for the type of lookup. For a query-style lookup, there
2963 is no file name, and the "key" is just the query. For query-style with a file
2964 name, we have to fish the file off the start of the query. For a single-key
2965 lookup, the key is the current IP address, masked appropriately, and
2966 reconverted to text form, with the mask appended. For IPv6 addresses, specify
2967 dot separators instead of colons, except when the lookup type is "iplsearch".
2968 */
2969
2970 if (mac_islookup(search_type, lookup_absfilequery))
2971 {
2972 filename = semicolon + 1;
2973 key = filename;
2974 while (*key != 0 && !isspace(*key)) key++;
2975 filename = string_copyn(filename, key - filename);
2976 while (isspace(*key)) key++;
2977 }
2978 else if (mac_islookup(search_type, lookup_querystyle))
2979 {
2980 filename = NULL;
2981 key = semicolon + 1;
2982 }
2983 else /* Single-key style */
2984 {
2985 int sep = (Ustrcmp(lookup_list[search_type]->name, "iplsearch") == 0)?
2986 ':' : '.';
2987 insize = host_aton(cb->host_address, incoming);
2988 host_mask(insize, incoming, mlen);
2989 (void)host_nmtoa(insize, incoming, mlen, buffer, sep);
2990 key = buffer;
2991 filename = semicolon + 1;
2992 }
2993
2994 /* Now do the actual lookup; note that there is no search_close() because
2995 of the caching arrangements. */
2996
2997 if (!(handle = search_open(filename, search_type, 0, NULL, NULL)))
2998 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s", search_error_message);
2999
3000 result = search_find(handle, filename, key, -1, NULL, 0, 0, NULL);
3001 if (valueptr != NULL) *valueptr = result;
3002 return (result != NULL)? OK : search_find_defer? DEFER: FAIL;
3003 }
3004
3005 /* The pattern is not an IP address or network reference of any kind. That is,
3006 it is a host name pattern. If this is an IP only match, there's an error in the
3007 host list. */
3008
3009 if (isiponly)
3010 {
3011 *error = US"cannot match host name in match_ip list";
3012 return ERROR;
3013 }
3014
3015 /* Check the characters of the pattern to see if they comprise only letters,
3016 digits, full stops, and hyphens (the constituents of domain names). Allow
3017 underscores, as they are all too commonly found. Sigh. Also, if
3018 allow_utf8_domains is set, allow top-bit characters. */
3019
3020 for (t = ss; *t != 0; t++)
3021 if (!isalnum(*t) && *t != '.' && *t != '-' && *t != '_' &&
3022 (!allow_utf8_domains || *t < 128)) break;
3023
3024 /* If the pattern is a complete domain name, with no fancy characters, look up
3025 its IP address and match against that. Note that a multi-homed host will add
3026 items to the chain. */
3027
3028 if (*t == 0)
3029 {
3030 int rc;
3031 host_item h;
3032 h.next = NULL;
3033 h.name = ss;
3034 h.address = NULL;
3035 h.mx = MX_NONE;
3036
3037 /* Using byname rather than bydns here means we cannot determine dnssec
3038 status. On the other hand it is unclear how that could be either
3039 propagated up or enforced. */
3040
3041 rc = host_find_byname(&h, NULL, HOST_FIND_QUALIFY_SINGLE, NULL, FALSE);
3042 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
3043 {
3044 host_item *hh;
3045 for (hh = &h; hh != NULL; hh = hh->next)
3046 {
3047 if (host_is_in_net(hh->address, cb->host_address, 0)) return OK;
3048 }
3049 return FAIL;
3050 }
3051 if (rc == HOST_FIND_AGAIN) return DEFER;
3052 *error = string_sprintf("failed to find IP address for %s", ss);
3053 return ERROR;
3054 }
3055
3056 /* Almost all subsequent comparisons require the host name, and can be done
3057 using the general string matching function. When this function is called for
3058 outgoing hosts, the name is always given explicitly. If it is NULL, it means we
3059 must use sender_host_name and its aliases, looking them up if necessary. */
3060
3061 if (cb->host_name != NULL) /* Explicit host name given */
3062 return match_check_string(cb->host_name, ss, -1, TRUE, TRUE, TRUE,
3063 valueptr);
3064
3065 /* Host name not given; in principle we need the sender host name and its
3066 aliases. However, for query-style lookups, we do not need the name if the
3067 query does not contain $sender_host_name. From release 4.23, a reference to
3068 $sender_host_name causes it to be looked up, so we don't need to do the lookup
3069 on spec. */
3070
3071 if ((semicolon = Ustrchr(ss, ';')) != NULL)
3072 {
3073 const uschar *affix;
3074 int partial, affixlen, starflags, id;
3075
3076 *semicolon = 0;
3077 id = search_findtype_partial(ss, &partial, &affix, &affixlen, &starflags);
3078 *semicolon=';';
3079
3080 if (id < 0) /* Unknown lookup type */
3081 {
3082 log_write(0, LOG_MAIN|LOG_PANIC, "%s in host list item \"%s\"",
3083 search_error_message, ss);
3084 return DEFER;
3085 }
3086 isquery = mac_islookup(id, lookup_querystyle|lookup_absfilequery);
3087 }
3088
3089 if (isquery)
3090 {
3091 switch(match_check_string(US"", ss, -1, TRUE, TRUE, TRUE, valueptr))
3092 {
3093 case OK: return OK;
3094 case DEFER: return DEFER;
3095 default: return FAIL;
3096 }
3097 }
3098
3099 /* Not a query-style lookup; must ensure the host name is present, and then we
3100 do a check on the name and all its aliases. */
3101
3102 if (!sender_host_name)
3103 {
3104 HDEBUG(D_host_lookup)
3105 debug_printf("sender host name required, to match against %s\n", ss);
3106 if (host_lookup_failed || host_name_lookup() != OK)
3107 {
3108 *error = string_sprintf("failed to find host name for %s",
3109 sender_host_address);;
3110 return ERROR;
3111 }
3112 host_build_sender_fullhost();
3113 }
3114
3115 /* Match on the sender host name, using the general matching function */
3116
3117 switch(match_check_string(sender_host_name, ss, -1, TRUE, TRUE, TRUE, valueptr))
3118 {
3119 case OK: return OK;
3120 case DEFER: return DEFER;
3121 }
3122
3123 /* If there are aliases, try matching on them. */
3124
3125 aliases = sender_host_aliases;
3126 while (*aliases)
3127 switch(match_check_string(*aliases++, ss, -1, TRUE, TRUE, TRUE, valueptr))
3128 {
3129 case OK: return OK;
3130 case DEFER: return DEFER;
3131 }
3132 return FAIL;
3133 }
3134
3135
3136
3137
3138 /*************************************************
3139 * Check a specific host matches a host list *
3140 *************************************************/
3141
3142 /* This function is passed a host list containing items in a number of
3143 different formats and the identity of a host. Its job is to determine whether
3144 the given host is in the set of hosts defined by the list. The host name is
3145 passed as a pointer so that it can be looked up if needed and not already
3146 known. This is commonly the case when called from verify_check_host() to check
3147 an incoming connection. When called from elsewhere the host name should usually
3148 be set.
3149
3150 This function is now just a front end to match_check_list(), which runs common
3151 code for scanning a list. We pass it the check_host() function to perform a
3152 single test.
3153
3154 Arguments:
3155 listptr pointer to the host list
3156 cache_bits pointer to cache for named lists, or NULL
3157 host_name the host name or NULL, implying use sender_host_name and
3158 sender_host_aliases, looking them up if required
3159 host_address the IP address
3160 valueptr if not NULL, data from a lookup is passed back here
3161
3162 Returns: OK if the host is in the defined set
3163 FAIL if the host is not in the defined set,
3164 DEFER if a data lookup deferred (not a host lookup)
3165
3166 If the host name was needed in order to make a comparison, and could not be
3167 determined from the IP address, the result is FAIL unless the item
3168 "+allow_unknown" was met earlier in the list, in which case OK is returned. */
3169
3170 int
3171 verify_check_this_host(const uschar **listptr, unsigned int *cache_bits,
3172 const uschar *host_name, const uschar *host_address, const uschar **valueptr)
3173 {
3174 int rc;
3175 unsigned int *local_cache_bits = cache_bits;
3176 const uschar *save_host_address = deliver_host_address;
3177 check_host_block cb = { .host_name = host_name, .host_address = host_address };
3178
3179 if (valueptr) *valueptr = NULL;
3180
3181 /* If the host address starts off ::ffff: it is an IPv6 address in
3182 IPv4-compatible mode. Find the IPv4 part for checking against IPv4
3183 addresses. */
3184
3185 cb.host_ipv4 = Ustrncmp(host_address, "::ffff:", 7) == 0
3186 ? host_address + 7 : host_address;
3187
3188 /* During the running of the check, put the IP address into $host_address. In
3189 the case of calls from the smtp transport, it will already be there. However,
3190 in other calls (e.g. when testing ignore_target_hosts), it won't. Just to be on
3191 the safe side, any existing setting is preserved, though as I write this
3192 (November 2004) I can't see any cases where it is actually needed. */
3193
3194 deliver_host_address = host_address;
3195 rc = match_check_list(
3196 listptr, /* the list */
3197 0, /* separator character */
3198 &hostlist_anchor, /* anchor pointer */
3199 &local_cache_bits, /* cache pointer */
3200 check_host, /* function for testing */
3201 &cb, /* argument for function */
3202 MCL_HOST, /* type of check */
3203 (host_address == sender_host_address)?
3204 US"host" : host_address, /* text for debugging */
3205 valueptr); /* where to pass back data */
3206 deliver_host_address = save_host_address;
3207 return rc;
3208 }
3209
3210
3211
3212
3213 /*************************************************
3214 * Check the given host item matches a list *
3215 *************************************************/
3216 int
3217 verify_check_given_host(uschar **listptr, host_item *host)
3218 {
3219 return verify_check_this_host(CUSS listptr, NULL, host->name, host->address, NULL);
3220 }
3221
3222 /*************************************************
3223 * Check the remote host matches a list *
3224 *************************************************/
3225
3226 /* This is a front end to verify_check_this_host(), created because checking
3227 the remote host is a common occurrence. With luck, a good compiler will spot
3228 the tail recursion and optimize it. If there's no host address, this is
3229 command-line SMTP input - check against an empty string for the address.
3230
3231 Arguments:
3232 listptr pointer to the host list
3233
3234 Returns: the yield of verify_check_this_host(),
3235 i.e. OK, FAIL, or DEFER
3236 */
3237
3238 int
3239 verify_check_host(uschar **listptr)
3240 {
3241 return verify_check_this_host(CUSS listptr, sender_host_cache, NULL,
3242 (sender_host_address == NULL)? US"" : sender_host_address, NULL);
3243 }
3244
3245
3246
3247
3248
3249 /*************************************************
3250 * Invert an IP address *
3251 *************************************************/
3252
3253 /* Originally just used for DNS xBL lists, now also used for the
3254 reverse_ip expansion operator.
3255
3256 Arguments:
3257 buffer where to put the answer
3258 address the address to invert
3259 */
3260
3261 void
3262 invert_address(uschar *buffer, uschar *address)
3263 {
3264 int bin[4];
3265 uschar *bptr = buffer;
3266
3267 /* If this is an IPv4 address mapped into IPv6 format, adjust the pointer
3268 to the IPv4 part only. */
3269
3270 if (Ustrncmp(address, "::ffff:", 7) == 0) address += 7;
3271
3272 /* Handle IPv4 address: when HAVE_IPV6 is false, the result of host_aton() is
3273 always 1. */
3274
3275 if (host_aton(address, bin) == 1)
3276 {
3277 int i;
3278 int x = bin[0];
3279 for (i = 0; i < 4; i++)
3280 {
3281 sprintf(CS bptr, "%d.", x & 255);
3282 while (*bptr) bptr++;
3283 x >>= 8;
3284 }
3285 }
3286
3287 /* Handle IPv6 address. Actually, as far as I know, there are no IPv6 addresses
3288 in any DNS black lists, and the format in which they will be looked up is
3289 unknown. This is just a guess. */
3290
3291 #if HAVE_IPV6
3292 else
3293 {
3294 int i, j;
3295 for (j = 3; j >= 0; j--)
3296 {
3297 int x = bin[j];
3298 for (i = 0; i < 8; i++)
3299 {
3300 sprintf(CS bptr, "%x.", x & 15);
3301 while (*bptr) bptr++;
3302 x >>= 4;
3303 }
3304 }
3305 }
3306 #endif
3307
3308 /* Remove trailing period -- this is needed so that both arbitrary
3309 dnsbl keydomains and inverted addresses may be combined with the
3310 same format string, "%s.%s" */
3311
3312 *(--bptr) = 0;
3313 }
3314
3315
3316
3317 /*************************************************
3318 * Perform a single dnsbl lookup *
3319 *************************************************/
3320
3321 /* This function is called from verify_check_dnsbl() below. It is also called
3322 recursively from within itself when domain and domain_txt are different
3323 pointers, in order to get the TXT record from the alternate domain.
3324
3325 Arguments:
3326 domain the outer dnsbl domain
3327 domain_txt alternate domain to lookup TXT record on success; when the
3328 same domain is to be used, domain_txt == domain (that is,
3329 the pointers must be identical, not just the text)
3330 keydomain the current keydomain (for debug message)
3331 prepend subdomain to lookup (like keydomain, but
3332 reversed if IP address)
3333 iplist the list of matching IP addresses, or NULL for "any"
3334 bitmask true if bitmask matching is wanted
3335 match_type condition for 'succeed' result
3336 0 => Any RR in iplist (=)
3337 1 => No RR in iplist (!=)
3338 2 => All RRs in iplist (==)
3339 3 => Some RRs not in iplist (!==)
3340 the two bits are defined as MT_NOT and MT_ALL
3341 defer_return what to return for a defer
3342
3343 Returns: OK if lookup succeeded
3344 FAIL if not
3345 */
3346
3347 static int
3348 one_check_dnsbl(uschar *domain, uschar *domain_txt, uschar *keydomain,
3349 uschar *prepend, uschar *iplist, BOOL bitmask, int match_type,
3350 int defer_return)
3351 {
3352 dns_answer dnsa;
3353 dns_scan dnss;
3354 tree_node *t;
3355 dnsbl_cache_block *cb;
3356 int old_pool = store_pool;
3357 uschar query[256]; /* DNS domain max length */
3358
3359 /* Construct the specific query domainname */
3360
3361 if (!string_format(query, sizeof(query), "%s.%s", prepend, domain))
3362 {
3363 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
3364 "(ignored): %s...", query);
3365 return FAIL;
3366 }
3367
3368 /* Look for this query in the cache. */
3369
3370 if ( (t = tree_search(dnsbl_cache, query))
3371 && (cb = t->data.ptr)->expiry > time(NULL)
3372 )
3373
3374 /* Previous lookup was cached */
3375
3376 {
3377 HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
3378 }
3379
3380 /* If not cached from a previous lookup, we must do a DNS lookup, and
3381 cache the result in permanent memory. */
3382
3383 else
3384 {
3385 uint ttl = 3600;
3386
3387 store_pool = POOL_PERM;
3388
3389 if (t)
3390 {
3391 HDEBUG(D_dnsbl) debug_printf("cached data found but past valid time; ");
3392 }
3393
3394 else
3395 { /* Set up a tree entry to cache the lookup */
3396 t = store_get(sizeof(tree_node) + Ustrlen(query));
3397 Ustrcpy(t->name, query);
3398 t->data.ptr = cb = store_get(sizeof(dnsbl_cache_block));
3399 (void)tree_insertnode(&dnsbl_cache, t);
3400 }
3401
3402 /* Do the DNS lookup . */
3403
3404 HDEBUG(D_dnsbl) debug_printf("new DNS lookup for %s\n", query);
3405 cb->rc = dns_basic_lookup(&dnsa, query, T_A);
3406 cb->text_set = FALSE;
3407 cb->text = NULL;
3408 cb->rhs = NULL;
3409
3410 /* If the lookup succeeded, cache the RHS address. The code allows for
3411 more than one address - this was for complete generality and the possible
3412 use of A6 records. However, A6 records have been reduced to experimental
3413 status (August 2001) and may die out. So they may never get used at all,
3414 let alone in dnsbl records. However, leave the code here, just in case.
3415
3416 Quite apart from one A6 RR generating multiple addresses, there are DNS
3417 lists that return more than one A record, so we must handle multiple
3418 addresses generated in that way as well.
3419
3420 Mark the cache entry with the "now" plus the minimum of the address TTLs,
3421 or some suitably far-future time if none were found. */
3422
3423 if (cb->rc == DNS_SUCCEED)
3424 {
3425 dns_record *rr;
3426 dns_address **addrp = &(cb->rhs);
3427 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
3428 rr;
3429 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3430 if (rr->type == T_A)
3431 {
3432 dns_address *da = dns_address_from_rr(&dnsa, rr);
3433 if (da)
3434 {
3435 *addrp = da;
3436 while (da->next) da = da->next;
3437 addrp = &da->next;
3438 if (ttl > rr->ttl) ttl = rr->ttl;
3439 }
3440 }
3441
3442 /* If we didn't find any A records, change the return code. This can
3443 happen when there is a CNAME record but there are no A records for what
3444 it points to. */
3445
3446 if (!cb->rhs) cb->rc = DNS_NODATA;
3447 }
3448
3449 cb->expiry = time(NULL)+ttl;
3450 store_pool = old_pool;
3451 }
3452
3453 /* We now have the result of the DNS lookup, either newly done, or cached
3454 from a previous call. If the lookup succeeded, check against the address
3455 list if there is one. This may be a positive equality list (introduced by
3456 "="), a negative equality list (introduced by "!="), a positive bitmask
3457 list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/
3458
3459 if (cb->rc == DNS_SUCCEED)
3460 {
3461 dns_address *da = NULL;
3462 uschar *addlist = cb->rhs->address;
3463
3464 /* For A and AAAA records, there may be multiple addresses from multiple
3465 records. For A6 records (currently not expected to be used) there may be
3466 multiple addresses from a single record. */
3467
3468 for (da = cb->rhs->next; da; da = da->next)
3469 addlist = string_sprintf("%s, %s", addlist, da->address);
3470
3471 HDEBUG(D_dnsbl) debug_printf("DNS lookup for %s succeeded (yielding %s)\n",
3472 query, addlist);
3473
3474 /* Address list check; this can be either for equality, or via a bitmask.
3475 In the latter case, all the bits must match. */
3476
3477 if (iplist)
3478 {
3479 for (da = cb->rhs; da; da = da->next)
3480 {
3481 int ipsep = ',';
3482 uschar ip[46];
3483 const uschar *ptr = iplist;
3484 uschar *res;
3485
3486 /* Handle exact matching */
3487
3488 if (!bitmask)
3489 {
3490 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))))
3491 if (Ustrcmp(CS da->address, ip) == 0)
3492 break;
3493 }
3494
3495 /* Handle bitmask matching */
3496
3497 else
3498 {
3499 int address[4];
3500 int mask = 0;
3501
3502 /* At present, all known DNS blocking lists use A records, with
3503 IPv4 addresses on the RHS encoding the information they return. I
3504 wonder if this will linger on as the last vestige of IPv4 when IPv6
3505 is ubiquitous? Anyway, for now we use paranoia code to completely
3506 ignore IPv6 addresses. The default mask is 0, which always matches.
3507 We change this only for IPv4 addresses in the list. */
3508
3509 if (host_aton(da->address, address) == 1) mask = address[0];
3510
3511 /* Scan the returned addresses, skipping any that are IPv6 */
3512
3513 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))))
3514 {
3515 if (host_aton(ip, address) != 1) continue;
3516 if ((address[0] & mask) == address[0]) break;
3517 }
3518 }
3519
3520 /* If either
3521
3522 (a) An IP address in an any ('=') list matched, or
3523 (b) No IP address in an all ('==') list matched
3524
3525 then we're done searching. */
3526
3527 if (((match_type & MT_ALL) != 0) == (res == NULL)) break;
3528 }
3529
3530 /* If da == NULL, either
3531
3532 (a) No IP address in an any ('=') list matched, or
3533 (b) An IP address in an all ('==') list didn't match
3534
3535 so behave as if the DNSBL lookup had not succeeded, i.e. the host is not on
3536 the list. */
3537
3538 if ((match_type == MT_NOT || match_type == MT_ALL) != (da == NULL))
3539 {
3540 HDEBUG(D_dnsbl)
3541 {
3542 uschar *res = NULL;
3543 switch(match_type)
3544 {
3545 case 0:
3546 res = US"was no match"; break;
3547 case MT_NOT:
3548 res = US"was an exclude match"; break;
3549 case MT_ALL:
3550 res = US"was an IP address that did not match"; break;
3551 case MT_NOT|MT_ALL:
3552 res = US"were no IP addresses that did not match"; break;
3553 }
3554 debug_printf("=> but we are not accepting this block class because\n");
3555 debug_printf("=> there %s for %s%c%s\n",
3556 res,
3557 ((match_type & MT_ALL) == 0)? "" : "=",
3558 bitmask? '&' : '=', iplist);
3559 }
3560 return FAIL;
3561 }
3562 }
3563
3564 /* Either there was no IP list, or the record matched, implying that the
3565 domain is on the list. We now want to find a corresponding TXT record. If an
3566 alternate domain is specified for the TXT record, call this function
3567 recursively to look that up; this has the side effect of re-checking that
3568 there is indeed an A record at the alternate domain. */
3569
3570 if (domain_txt != domain)
3571 return one_check_dnsbl(domain_txt, domain_txt, keydomain, prepend, NULL,
3572 FALSE, match_type, defer_return);
3573
3574 /* If there is no alternate domain, look up a TXT record in the main domain
3575 if it has not previously been cached. */
3576
3577 if (!cb->text_set)
3578 {
3579 cb->text_set = TRUE;
3580 if (dns_basic_lookup(&dnsa, query, T_TXT) == DNS_SUCCEED)
3581 {
3582 dns_record *rr;
3583 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
3584 rr;
3585 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3586 if (rr->type == T_TXT) break;
3587 if (rr)
3588 {
3589 int len = (rr->data)[0];
3590 if (len > 511) len = 127;
3591 store_pool = POOL_PERM;
3592 cb->text = string_sprintf("%.*s", len, CUS (rr->data+1));
3593 store_pool = old_pool;
3594 }
3595 }
3596 }
3597
3598 dnslist_value = addlist;
3599 dnslist_text = cb->text;
3600 return OK;
3601 }
3602
3603 /* There was a problem with the DNS lookup */
3604
3605 if (cb->rc != DNS_NOMATCH && cb->rc != DNS_NODATA)
3606 {
3607 log_write(L_dnslist_defer, LOG_MAIN,
3608 "DNS list lookup defer (probably timeout) for %s: %s", query,
3609 (defer_return == OK)? US"assumed in list" :
3610 (defer_return == FAIL)? US"assumed not in list" :
3611 US"returned DEFER");
3612 return defer_return;
3613 }
3614
3615 /* No entry was found in the DNS; continue for next domain */
3616
3617 HDEBUG(D_dnsbl)
3618 {
3619 debug_printf("DNS lookup for %s failed\n", query);
3620 debug_printf("=> that means %s is not listed at %s\n",
3621 keydomain, domain);
3622 }
3623
3624 return FAIL;
3625 }
3626
3627
3628
3629
3630 /*************************************************
3631 * Check host against DNS black lists *
3632 *************************************************/
3633
3634 /* This function runs checks against a list of DNS black lists, until one
3635 matches. Each item on the list can be of the form
3636
3637 domain=ip-address/key
3638
3639 The domain is the right-most domain that is used for the query, for example,
3640 blackholes.mail-abuse.org. If the IP address is present, there is a match only
3641 if the DNS lookup returns a matching IP address. Several addresses may be
3642 given, comma-separated, for example: x.y.z=127.0.0.1,127.0.0.2.
3643
3644 If no key is given, what is looked up in the domain is the inverted IP address
3645 of the current client host. If a key is given, it is used to construct the
3646 domain for the lookup. For example:
3647
3648 dsn.rfc-ignorant.org/$sender_address_domain
3649
3650 After finding a match in the DNS, the domain is placed in $dnslist_domain, and
3651 then we check for a TXT record for an error message, and if found, save its
3652 value in $dnslist_text. We also cache everything in a tree, to optimize
3653 multiple lookups.
3654
3655 The TXT record is normally looked up in the same domain as the A record, but
3656 when many lists are combined in a single DNS domain, this will not be a very
3657 specific message. It is possible to specify a different domain for looking up
3658 TXT records; this is given before the main domain, comma-separated. For
3659 example:
3660
3661 dnslists = http.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.2 : \
3662 socks.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.3
3663
3664 The caching ensures that only one lookup in dnsbl.sorbs.net is done.
3665
3666 Note: an address for testing RBL is 192.203.178.39
3667 Note: an address for testing DUL is 192.203.178.4
3668 Note: a domain for testing RFCI is example.tld.dsn.rfc-ignorant.org
3669
3670 Arguments:
3671 where the acl type
3672 listptr the domain/address/data list
3673 log_msgptr log message on error
3674
3675 Returns: OK successful lookup (i.e. the address is on the list), or
3676 lookup deferred after +include_unknown
3677 FAIL name not found, or no data found for the given type, or
3678 lookup deferred after +exclude_unknown (default)
3679 DEFER lookup failure, if +defer_unknown was set
3680 */
3681
3682 int
3683 verify_check_dnsbl(int where, const uschar ** listptr, uschar ** log_msgptr)
3684 {
3685 int sep = 0;
3686 int defer_return = FAIL;
3687 const uschar *list = *listptr;
3688 uschar *domain;
3689 uschar *s;
3690 uschar buffer[1024];
3691 uschar revadd[128]; /* Long enough for IPv6 address */
3692
3693 /* Indicate that the inverted IP address is not yet set up */
3694
3695 revadd[0] = 0;
3696
3697 /* In case this is the first time the DNS resolver is being used. */
3698
3699 dns_init(FALSE, FALSE, FALSE); /*XXX dnssec? */
3700
3701 /* Loop through all the domains supplied, until something matches */
3702
3703 while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
3704 {
3705 int rc;
3706 BOOL bitmask = FALSE;
3707 int match_type = 0;
3708 uschar *domain_txt;
3709 uschar *comma;
3710 uschar *iplist;
3711 uschar *key;
3712
3713 HDEBUG(D_dnsbl) debug_printf("DNS list check: %s\n", domain);
3714
3715 /* Deal with special values that change the behaviour on defer */
3716
3717 if (domain[0] == '+')
3718 {
3719 if (strcmpic(domain, US"+include_unknown") == 0) defer_return = OK;
3720 else if (strcmpic(domain, US"+exclude_unknown") == 0) defer_return = FAIL;
3721 else if (strcmpic(domain, US"+defer_unknown") == 0) defer_return = DEFER;
3722 else
3723 log_write(0, LOG_MAIN|LOG_PANIC, "unknown item in dnslist (ignored): %s",
3724 domain);
3725 continue;
3726 }
3727
3728 /* See if there's explicit data to be looked up */
3729
3730 if ((key = Ustrchr(domain, '/'))) *key++ = 0;
3731
3732 /* See if there's a list of addresses supplied after the domain name. This is
3733 introduced by an = or a & character; if preceded by = we require all matches
3734 and if preceded by ! we invert the result. */
3735
3736 if (!(iplist = Ustrchr(domain, '=')))
3737 {
3738 bitmask = TRUE;
3739 iplist = Ustrchr(domain, '&');
3740 }
3741
3742 if (iplist) /* Found either = or & */
3743 {
3744 if (iplist > domain && iplist[-1] == '!') /* Handle preceding ! */
3745 {
3746 match_type |= MT_NOT;
3747 iplist[-1] = 0;
3748 }
3749
3750 *iplist++ = 0; /* Terminate domain, move on */
3751
3752 /* If we found = (bitmask == FALSE), check for == or =& */
3753
3754 if (!bitmask && (*iplist == '=' || *iplist == '&'))
3755 {
3756 bitmask = *iplist++ == '&';
3757 match_type |= MT_ALL;
3758 }
3759 }
3760
3761
3762 /* If there is a comma in the domain, it indicates that a second domain for
3763 looking up TXT records is provided, before the main domain. Otherwise we must
3764 set domain_txt == domain. */
3765
3766 domain_txt = domain;
3767 comma = Ustrchr(domain, ',');
3768 if (comma != NULL)
3769 {
3770 *comma++ = 0;
3771 domain = comma;
3772 }
3773
3774 /* Check that what we have left is a sensible domain name. There is no reason
3775 why these domains should in fact use the same syntax as hosts and email
3776 domains, but in practice they seem to. However, there is little point in
3777 actually causing an error here, because that would no doubt hold up incoming
3778 mail. Instead, I'll just log it. */
3779
3780 for (s = domain; *s != 0; s++)
3781 {
3782 if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_')
3783 {
3784 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
3785 "strange characters - is this right?", domain);
3786 break;
3787 }
3788 }
3789
3790 /* Check the alternate domain if present */
3791
3792 if (domain_txt != domain) for (s = domain_txt; *s != 0; s++)
3793 {
3794 if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_')
3795 {
3796 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
3797 "strange characters - is this right?", domain_txt);
3798 break;
3799 }
3800 }
3801
3802 /* If there is no key string, construct the query by adding the domain name
3803 onto the inverted host address, and perform a single DNS lookup. */
3804
3805 if (key == NULL)
3806 {
3807 if (where == ACL_WHERE_NOTSMTP_START || where == ACL_WHERE_NOTSMTP)
3808 {
3809 *log_msgptr = string_sprintf
3810 ("cannot test auto-keyed dnslists condition in %s ACL",
3811 acl_wherenames[where]);
3812 return ERROR;
3813 }
3814 if (sender_host_address == NULL) return FAIL; /* can never match */
3815 if (revadd[0] == 0) invert_address(revadd, sender_host_address);
3816 rc = one_check_dnsbl(domain, domain_txt, sender_host_address, revadd,
3817 iplist, bitmask, match_type, defer_return);
3818 if (rc == OK)
3819 {
3820 dnslist_domain = string_copy(domain_txt);
3821 dnslist_matched = string_copy(sender_host_address);
3822 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
3823 sender_host_address, dnslist_domain);
3824 }
3825 if (rc != FAIL) return rc; /* OK or DEFER */
3826 }
3827
3828 /* If there is a key string, it can be a list of domains or IP addresses to
3829 be concatenated with the main domain. */
3830
3831 else
3832 {
3833 int keysep = 0;
3834 BOOL defer = FALSE;
3835 uschar *keydomain;
3836 uschar keybuffer[256];
3837 uschar keyrevadd[128];
3838
3839 while ((keydomain = string_nextinlist(CUSS &key, &keysep, keybuffer,
3840 sizeof(keybuffer))) != NULL)
3841 {
3842 uschar *prepend = keydomain;
3843
3844 if (string_is_ip_address(keydomain, NULL) != 0)
3845 {
3846 invert_address(keyrevadd, keydomain);
3847 prepend = keyrevadd;
3848 }
3849
3850 rc = one_check_dnsbl(domain, domain_txt, keydomain, prepend, iplist,
3851 bitmask, match_type, defer_return);
3852
3853 if (rc == OK)
3854 {
3855 dnslist_domain = string_copy(domain_txt);
3856 dnslist_matched = string_copy(keydomain);
3857 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
3858 keydomain, dnslist_domain);
3859 return OK;
3860 }
3861
3862 /* If the lookup deferred, remember this fact. We keep trying the rest
3863 of the list to see if we get a useful result, and if we don't, we return
3864 DEFER at the end. */
3865
3866 if (rc == DEFER) defer = TRUE;
3867 } /* continue with next keystring domain/address */
3868
3869 if (defer) return DEFER;
3870 }
3871 } /* continue with next dnsdb outer domain */
3872
3873 return FAIL;
3874 }
3875
3876 /* vi: aw ai sw=2
3877 */
3878 /* End of verify.c */