Support dnssec in verify-callout use of smtp transport.
[exim.git] / src / src / verify.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2014 */
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 address_item cutthrough_addr;
18 static smtp_outblock ctblock;
19 uschar ctbuffer[8192];
20
21
22 /* Structure for caching DNSBL lookups */
23
24 typedef struct dnsbl_cache_block {
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
43
44 /*************************************************
45 * Retrieve a callout cache record *
46 *************************************************/
47
48 /* If a record exists, check whether it has expired.
49
50 Arguments:
51 dbm_file an open hints file
52 key the record key
53 type "address" or "domain"
54 positive_expire expire time for positive records
55 negative_expire expire time for negative records
56
57 Returns: the cache record if a non-expired one exists, else NULL
58 */
59
60 static dbdata_callout_cache *
61 get_callout_cache_record(open_db *dbm_file, uschar *key, uschar *type,
62 int positive_expire, int negative_expire)
63 {
64 BOOL negative;
65 int length, expire;
66 time_t now;
67 dbdata_callout_cache *cache_record;
68
69 cache_record = dbfn_read_with_length(dbm_file, key, &length);
70
71 if (cache_record == NULL)
72 {
73 HDEBUG(D_verify) debug_printf("callout cache: no %s record found\n", type);
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\n", type);
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\n", type);
115 return cache_record;
116 }
117
118
119
120 /*************************************************
121 * Do callout verification for an address *
122 *************************************************/
123
124 /* This function is called from verify_address() when the address has routed to
125 a host list, and a callout has been requested. Callouts are expensive; that is
126 why a cache is used to improve the efficiency.
127
128 Arguments:
129 addr the address that's been routed
130 host_list the list of hosts to try
131 tf the transport feedback block
132
133 ifstring "interface" option from transport, or NULL
134 portstring "port" option from transport, or NULL
135 protocolstring "protocol" option from transport, or NULL
136 callout the per-command callout timeout
137 callout_overall the overall callout timeout (if < 0 use 4*callout)
138 callout_connect the callout connection timeout (if < 0 use callout)
139 options the verification options - these bits are used:
140 vopt_is_recipient => this is a recipient address
141 vopt_callout_no_cache => don't use callout cache
142 vopt_callout_fullpm => if postmaster check, do full one
143 vopt_callout_random => do the "random" thing
144 vopt_callout_recipsender => use real sender for recipient
145 vopt_callout_recippmaster => use postmaster for recipient
146 se_mailfrom MAIL FROM address for sender verify; NULL => ""
147 pm_mailfrom if non-NULL, do the postmaster check with this sender
148
149 Returns: OK/FAIL/DEFER
150 */
151
152 static int
153 do_callout(address_item *addr, host_item *host_list, transport_feedback *tf,
154 int callout, int callout_overall, int callout_connect, int options,
155 uschar *se_mailfrom, uschar *pm_mailfrom)
156 {
157 BOOL is_recipient = (options & vopt_is_recipient) != 0;
158 BOOL callout_no_cache = (options & vopt_callout_no_cache) != 0;
159 BOOL callout_random = (options & vopt_callout_random) != 0;
160
161 int yield = OK;
162 int old_domain_cache_result = ccache_accept;
163 BOOL done = FALSE;
164 uschar *address_key;
165 uschar *from_address;
166 uschar *random_local_part = NULL;
167 uschar *save_deliver_domain = deliver_domain;
168 uschar **failure_ptr = is_recipient?
169 &recipient_verify_failure : &sender_verify_failure;
170 open_db dbblock;
171 open_db *dbm_file = NULL;
172 dbdata_callout_cache new_domain_record;
173 dbdata_callout_cache_address new_address_record;
174 host_item *host;
175 time_t callout_start_time;
176
177 new_domain_record.result = ccache_unknown;
178 new_domain_record.postmaster_result = ccache_unknown;
179 new_domain_record.random_result = ccache_unknown;
180
181 memset(&new_address_record, 0, sizeof(new_address_record));
182
183 /* For a recipient callout, the key used for the address cache record must
184 include the sender address if we are using the real sender in the callout,
185 because that may influence the result of the callout. */
186
187 address_key = addr->address;
188 from_address = US"";
189
190 if (is_recipient)
191 {
192 if ((options & vopt_callout_recipsender) != 0)
193 {
194 address_key = string_sprintf("%s/<%s>", addr->address, sender_address);
195 from_address = sender_address;
196 }
197 else if ((options & vopt_callout_recippmaster) != 0)
198 {
199 address_key = string_sprintf("%s/<postmaster@%s>", addr->address,
200 qualify_domain_sender);
201 from_address = string_sprintf("postmaster@%s", qualify_domain_sender);
202 }
203 }
204
205 /* For a sender callout, we must adjust the key if the mailfrom address is not
206 empty. */
207
208 else
209 {
210 from_address = (se_mailfrom == NULL)? US"" : se_mailfrom;
211 if (from_address[0] != 0)
212 address_key = string_sprintf("%s/<%s>", addr->address, from_address);
213 }
214
215 /* Open the callout cache database, it it exists, for reading only at this
216 stage, unless caching has been disabled. */
217
218 if (callout_no_cache)
219 {
220 HDEBUG(D_verify) debug_printf("callout cache: disabled by no_cache\n");
221 }
222 else if ((dbm_file = dbfn_open(US"callout", O_RDWR, &dbblock, FALSE)) == NULL)
223 {
224 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
225 }
226
227 /* If a cache database is available see if we can avoid the need to do an
228 actual callout by making use of previously-obtained data. */
229
230 if (dbm_file != NULL)
231 {
232 dbdata_callout_cache_address *cache_address_record;
233 dbdata_callout_cache *cache_record = get_callout_cache_record(dbm_file,
234 addr->domain, US"domain",
235 callout_cache_domain_positive_expire,
236 callout_cache_domain_negative_expire);
237
238 /* If an unexpired cache record was found for this domain, see if the callout
239 process can be short-circuited. */
240
241 if (cache_record != NULL)
242 {
243 /* In most cases, if an early command (up to and including MAIL FROM:<>)
244 was rejected, there is no point carrying on. The callout fails. However, if
245 we are doing a recipient verification with use_sender or use_postmaster
246 set, a previous failure of MAIL FROM:<> doesn't count, because this time we
247 will be using a non-empty sender. We have to remember this situation so as
248 not to disturb the cached domain value if this whole verification succeeds
249 (we don't want it turning into "accept"). */
250
251 old_domain_cache_result = cache_record->result;
252
253 if (cache_record->result == ccache_reject ||
254 (*from_address == 0 && cache_record->result == ccache_reject_mfnull))
255 {
256 setflag(addr, af_verify_nsfail);
257 HDEBUG(D_verify)
258 debug_printf("callout cache: domain gave initial rejection, or "
259 "does not accept HELO or MAIL FROM:<>\n");
260 setflag(addr, af_verify_nsfail);
261 addr->user_message = US"(result of an earlier callout reused).";
262 yield = FAIL;
263 *failure_ptr = US"mail";
264 goto END_CALLOUT;
265 }
266
267 /* If a previous check on a "random" local part was accepted, we assume
268 that the server does not do any checking on local parts. There is therefore
269 no point in doing the callout, because it will always be successful. If a
270 random check previously failed, arrange not to do it again, but preserve
271 the data in the new record. If a random check is required but hasn't been
272 done, skip the remaining cache processing. */
273
274 if (callout_random) switch(cache_record->random_result)
275 {
276 case ccache_accept:
277 HDEBUG(D_verify)
278 debug_printf("callout cache: domain accepts random addresses\n");
279 goto END_CALLOUT; /* Default yield is OK */
280
281 case ccache_reject:
282 HDEBUG(D_verify)
283 debug_printf("callout cache: domain rejects random addresses\n");
284 callout_random = FALSE;
285 new_domain_record.random_result = ccache_reject;
286 new_domain_record.random_stamp = cache_record->random_stamp;
287 break;
288
289 default:
290 HDEBUG(D_verify)
291 debug_printf("callout cache: need to check random address handling "
292 "(not cached or cache expired)\n");
293 goto END_CACHE;
294 }
295
296 /* If a postmaster check is requested, but there was a previous failure,
297 there is again no point in carrying on. If a postmaster check is required,
298 but has not been done before, we are going to have to do a callout, so skip
299 remaining cache processing. */
300
301 if (pm_mailfrom != NULL)
302 {
303 if (cache_record->postmaster_result == ccache_reject)
304 {
305 setflag(addr, af_verify_pmfail);
306 HDEBUG(D_verify)
307 debug_printf("callout cache: domain does not accept "
308 "RCPT TO:<postmaster@domain>\n");
309 yield = FAIL;
310 *failure_ptr = US"postmaster";
311 setflag(addr, af_verify_pmfail);
312 addr->user_message = US"(result of earlier verification reused).";
313 goto END_CALLOUT;
314 }
315 if (cache_record->postmaster_result == ccache_unknown)
316 {
317 HDEBUG(D_verify)
318 debug_printf("callout cache: need to check RCPT "
319 "TO:<postmaster@domain> (not cached or cache expired)\n");
320 goto END_CACHE;
321 }
322
323 /* If cache says OK, set pm_mailfrom NULL to prevent a redundant
324 postmaster check if the address itself has to be checked. Also ensure
325 that the value in the cache record is preserved (with its old timestamp).
326 */
327
328 HDEBUG(D_verify) debug_printf("callout cache: domain accepts RCPT "
329 "TO:<postmaster@domain>\n");
330 pm_mailfrom = NULL;
331 new_domain_record.postmaster_result = ccache_accept;
332 new_domain_record.postmaster_stamp = cache_record->postmaster_stamp;
333 }
334 }
335
336 /* We can't give a result based on information about the domain. See if there
337 is an unexpired cache record for this specific address (combined with the
338 sender address if we are doing a recipient callout with a non-empty sender).
339 */
340
341 cache_address_record = (dbdata_callout_cache_address *)
342 get_callout_cache_record(dbm_file,
343 address_key, US"address",
344 callout_cache_positive_expire,
345 callout_cache_negative_expire);
346
347 if (cache_address_record != NULL)
348 {
349 if (cache_address_record->result == ccache_accept)
350 {
351 HDEBUG(D_verify)
352 debug_printf("callout cache: address record is positive\n");
353 }
354 else
355 {
356 HDEBUG(D_verify)
357 debug_printf("callout cache: address record is negative\n");
358 addr->user_message = US"Previous (cached) callout verification failure";
359 *failure_ptr = US"recipient";
360 yield = FAIL;
361 }
362 goto END_CALLOUT;
363 }
364
365 /* Close the cache database while we actually do the callout for real. */
366
367 END_CACHE:
368 dbfn_close(dbm_file);
369 dbm_file = NULL;
370 }
371
372 if (!addr->transport)
373 {
374 HDEBUG(D_verify) debug_printf("cannot callout via null transport\n");
375 }
376 else if (Ustrcmp(addr->transport->driver_name, "smtp") != 0)
377 log_write(0, LOG_MAIN|LOG_PANIC|LOG_CONFIG_FOR, "callout transport '%s': %s is non-smtp",
378 addr->transport->name, addr->transport->driver_name);
379 else
380 {
381 smtp_transport_options_block *ob =
382 (smtp_transport_options_block *)addr->transport->options_block;
383
384 /* The information wasn't available in the cache, so we have to do a real
385 callout and save the result in the cache for next time, unless no_cache is set,
386 or unless we have a previously cached negative random result. If we are to test
387 with a random local part, ensure that such a local part is available. If not,
388 log the fact, but carry on without randomming. */
389
390 if (callout_random && callout_random_local_part != NULL)
391 {
392 random_local_part = expand_string(callout_random_local_part);
393 if (random_local_part == NULL)
394 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand "
395 "callout_random_local_part: %s", expand_string_message);
396 }
397
398 /* Default the connect and overall callout timeouts if not set, and record the
399 time we are starting so that we can enforce it. */
400
401 if (callout_overall < 0) callout_overall = 4 * callout;
402 if (callout_connect < 0) callout_connect = callout;
403 callout_start_time = time(NULL);
404
405 /* Before doing a real callout, if this is an SMTP connection, flush the SMTP
406 output because a callout might take some time. When PIPELINING is active and
407 there are many recipients, the total time for doing lots of callouts can add up
408 and cause the client to time out. So in this case we forgo the PIPELINING
409 optimization. */
410
411 if (smtp_out != NULL && !disable_callout_flush) mac_smtp_fflush();
412
413 /* Now make connections to the hosts and do real callouts. The list of hosts
414 is passed in as an argument. */
415
416 for (host = host_list; host != NULL && !done; host = host->next)
417 {
418 smtp_inblock inblock;
419 smtp_outblock outblock;
420 int host_af;
421 int port = 25;
422 BOOL send_quit = TRUE;
423 uschar *active_hostname = smtp_active_hostname;
424 BOOL lmtp;
425 BOOL smtps;
426 BOOL esmtp;
427 BOOL suppress_tls = FALSE;
428 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
429 uschar inbuffer[4096];
430 uschar outbuffer[1024];
431 uschar responsebuffer[4096];
432
433 clearflag(addr, af_verify_pmfail); /* postmaster callout flag */
434 clearflag(addr, af_verify_nsfail); /* null sender callout flag */
435
436 /* Skip this host if we don't have an IP address for it. */
437
438 if (host->address == NULL)
439 {
440 DEBUG(D_verify) debug_printf("no IP address for host name %s: skipping\n",
441 host->name);
442 continue;
443 }
444
445 /* Check the overall callout timeout */
446
447 if (time(NULL) - callout_start_time >= callout_overall)
448 {
449 HDEBUG(D_verify) debug_printf("overall timeout for callout exceeded\n");
450 break;
451 }
452
453 /* Set IPv4 or IPv6 */
454
455 host_af = (Ustrchr(host->address, ':') == NULL)? AF_INET:AF_INET6;
456
457 /* Expand and interpret the interface and port strings. The latter will not
458 be used if there is a host-specific port (e.g. from a manualroute router).
459 This has to be delayed till now, because they may expand differently for
460 different hosts. If there's a failure, log it, but carry on with the
461 defaults. */
462
463 deliver_host = host->name;
464 deliver_host_address = host->address;
465 deliver_domain = addr->domain;
466
467 if (!smtp_get_interface(tf->interface, host_af, addr, NULL, &interface,
468 US"callout") ||
469 !smtp_get_port(tf->port, addr, &port, US"callout"))
470 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
471 addr->message);
472
473 /* Set HELO string according to the protocol */
474 lmtp= Ustrcmp(tf->protocol, "lmtp") == 0;
475 smtps= Ustrcmp(tf->protocol, "smtps") == 0;
476
477
478 HDEBUG(D_verify) debug_printf("interface=%s port=%d\n", interface, port);
479
480 /* Set up the buffer for reading SMTP response packets. */
481
482 inblock.buffer = inbuffer;
483 inblock.buffersize = sizeof(inbuffer);
484 inblock.ptr = inbuffer;
485 inblock.ptrend = inbuffer;
486
487 /* Set up the buffer for holding SMTP commands while pipelining */
488
489 outblock.buffer = outbuffer;
490 outblock.buffersize = sizeof(outbuffer);
491 outblock.ptr = outbuffer;
492 outblock.cmd_count = 0;
493 outblock.authenticating = FALSE;
494
495 /* Reset the parameters of a TLS session */
496 tls_out.cipher = tls_out.peerdn = NULL;
497
498 /* Connect to the host; on failure, just loop for the next one, but we
499 set the error for the last one. Use the callout_connect timeout. */
500
501 tls_retry_connection:
502
503 inblock.sock = outblock.sock =
504 smtp_connect(host, host_af, port, interface, callout_connect, TRUE, NULL);
505 /* reconsider DSCP here */
506 if (inblock.sock < 0)
507 {
508 addr->message = string_sprintf("could not connect to %s [%s]: %s",
509 host->name, host->address, strerror(errno));
510 deliver_host = deliver_host_address = NULL;
511 deliver_domain = save_deliver_domain;
512 continue;
513 }
514
515 /* Expand the helo_data string to find the host name to use. */
516
517 if (tf->helo_data != NULL)
518 {
519 uschar *s = expand_string(tf->helo_data);
520 if (s == NULL)
521 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: failed to expand transport's "
522 "helo_data value for callout: %s", addr->address,
523 expand_string_message);
524 else active_hostname = s;
525 }
526
527 deliver_host = deliver_host_address = NULL;
528 deliver_domain = save_deliver_domain;
529
530 /* Wait for initial response, and send HELO. The smtp_write_command()
531 function leaves its command in big_buffer. This is used in error responses.
532 Initialize it in case the connection is rejected. */
533
534 Ustrcpy(big_buffer, "initial connection");
535
536 /* Unless ssl-on-connect, wait for the initial greeting */
537 smtps_redo_greeting:
538
539 #ifdef SUPPORT_TLS
540 if (!smtps || (smtps && tls_out.active >= 0))
541 #endif
542 if (!(done= smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), '2', callout)))
543 goto RESPONSE_FAILED;
544
545 /* Not worth checking greeting line for ESMTP support */
546 if (!(esmtp = verify_check_this_host(&(ob->hosts_avoid_esmtp), NULL,
547 host->name, host->address, NULL) != OK))
548 DEBUG(D_transport)
549 debug_printf("not sending EHLO (host matches hosts_avoid_esmtp)\n");
550
551 tls_redo_helo:
552
553 #ifdef SUPPORT_TLS
554 if (smtps && tls_out.active < 0) /* ssl-on-connect, first pass */
555 {
556 tls_offered = TRUE;
557 ob->tls_tempfail_tryclear = FALSE;
558 }
559 else /* all other cases */
560 #endif
561
562 { esmtp_retry:
563
564 if (!(done= smtp_write_command(&outblock, FALSE, "%s %s\r\n",
565 !esmtp? "HELO" : lmtp? "LHLO" : "EHLO", active_hostname) >= 0))
566 goto SEND_FAILED;
567 if (!smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), '2', callout))
568 {
569 if (errno != 0 || responsebuffer[0] == 0 || lmtp || !esmtp || tls_out.active >= 0)
570 {
571 done= FALSE;
572 goto RESPONSE_FAILED;
573 }
574 #ifdef SUPPORT_TLS
575 tls_offered = FALSE;
576 #endif
577 esmtp = FALSE;
578 goto esmtp_retry; /* fallback to HELO */
579 }
580
581 /* Set tls_offered if the response to EHLO specifies support for STARTTLS. */
582 #ifdef SUPPORT_TLS
583 if (esmtp && !suppress_tls && tls_out.active < 0)
584 {
585 if (regex_STARTTLS == NULL) regex_STARTTLS =
586 regex_must_compile(US"\\n250[\\s\\-]STARTTLS(\\s|\\n|$)", FALSE, TRUE);
587
588 tls_offered = pcre_exec(regex_STARTTLS, NULL, CS responsebuffer,
589 Ustrlen(responsebuffer), 0, PCRE_EOPT, NULL, 0) >= 0;
590 }
591 else
592 tls_offered = FALSE;
593 #endif
594 }
595
596 /* If TLS is available on this connection attempt to
597 start up a TLS session, unless the host is in hosts_avoid_tls. If successful,
598 send another EHLO - the server may give a different answer in secure mode. We
599 use a separate buffer for reading the response to STARTTLS so that if it is
600 negative, the original EHLO data is available for subsequent analysis, should
601 the client not be required to use TLS. If the response is bad, copy the buffer
602 for error analysis. */
603
604 #ifdef SUPPORT_TLS
605 if (tls_offered &&
606 verify_check_this_host(&(ob->hosts_avoid_tls), NULL, host->name,
607 host->address, NULL) != OK &&
608 verify_check_this_host(&(ob->hosts_verify_avoid_tls), NULL, host->name,
609 host->address, NULL) != OK
610 )
611 {
612 uschar buffer2[4096];
613 if ( !smtps
614 && !(done= smtp_write_command(&outblock, FALSE, "STARTTLS\r\n") >= 0))
615 goto SEND_FAILED;
616
617 /* If there is an I/O error, transmission of this message is deferred. If
618 there is a temporary rejection of STARRTLS and tls_tempfail_tryclear is
619 false, we also defer. However, if there is a temporary rejection of STARTTLS
620 and tls_tempfail_tryclear is true, or if there is an outright rejection of
621 STARTTLS, we carry on. This means we will try to send the message in clear,
622 unless the host is in hosts_require_tls (tested below). */
623
624 if (!smtps && !smtp_read_response(&inblock, buffer2, sizeof(buffer2), '2',
625 ob->command_timeout))
626 {
627 if (errno != 0 || buffer2[0] == 0 ||
628 (buffer2[0] == '4' && !ob->tls_tempfail_tryclear))
629 {
630 Ustrncpy(responsebuffer, buffer2, sizeof(responsebuffer));
631 done= FALSE;
632 goto RESPONSE_FAILED;
633 }
634 }
635
636 /* STARTTLS accepted or ssl-on-connect: try to negotiate a TLS session. */
637 else
638 {
639 int rc = tls_client_start(inblock.sock, host, addr,
640 ob->tls_certificate, ob->tls_privatekey,
641 ob->tls_sni,
642 ob->tls_verify_certificates, ob->tls_crl,
643 ob->tls_require_ciphers,
644 #ifdef EXPERIMENTAL_OCSP
645 ob->hosts_require_ocsp,
646 #endif
647 ob->tls_dh_min_bits, callout,
648 ob->tls_verify_hosts, ob->tls_try_verify_hosts);
649
650 /* TLS negotiation failed; give an error. Try in clear on a new connection,
651 if the options permit it for this host. */
652 if (rc != OK)
653 {
654 if (rc == DEFER && ob->tls_tempfail_tryclear && !smtps &&
655 verify_check_this_host(&(ob->hosts_require_tls), NULL, host->name,
656 host->address, NULL) != OK)
657 {
658 (void)close(inblock.sock);
659 log_write(0, LOG_MAIN, "TLS session failure: delivering unencrypted "
660 "to %s [%s] (not in hosts_require_tls)", host->name, host->address);
661 suppress_tls = TRUE;
662 goto tls_retry_connection;
663 }
664 /*save_errno = ERRNO_TLSFAILURE;*/
665 /*message = US"failure while setting up TLS session";*/
666 send_quit = FALSE;
667 done= FALSE;
668 goto TLS_FAILED;
669 }
670
671 /* TLS session is set up. Copy info for logging. */
672 addr->cipher = tls_out.cipher;
673 addr->peerdn = tls_out.peerdn;
674
675 /* For SMTPS we need to wait for the initial OK response, then do HELO. */
676 if (smtps)
677 goto smtps_redo_greeting;
678
679 /* For STARTTLS we need to redo EHLO */
680 goto tls_redo_helo;
681 }
682 }
683
684 /* If the host is required to use a secure channel, ensure that we have one. */
685 if (tls_out.active < 0)
686 if (verify_check_this_host(&(ob->hosts_require_tls), NULL, host->name,
687 host->address, NULL) == OK)
688 {
689 /*save_errno = ERRNO_TLSREQUIRED;*/
690 log_write(0, LOG_MAIN, "a TLS session is required for %s [%s], but %s",
691 host->name, host->address,
692 tls_offered? "an attempt to start TLS failed" : "the server did not offer TLS support");
693 done= FALSE;
694 goto TLS_FAILED;
695 }
696
697 #endif /*SUPPORT_TLS*/
698
699 done = TRUE; /* so far so good; have response to HELO */
700
701 /*XXX the EHLO response would be analyzed here for IGNOREQUOTA, SIZE, PIPELINING */
702
703 /* For now, transport_filter by cutthrough-delivery is not supported */
704 /* Need proper integration with the proper transport mechanism. */
705 if (cutthrough_delivery)
706 {
707 if (addr->transport->filter_command)
708 {
709 cutthrough_delivery= FALSE;
710 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of transport filter\n");
711 }
712 #ifndef DISABLE_DKIM
713 if (ob->dkim_domain)
714 {
715 cutthrough_delivery= FALSE;
716 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of DKIM signing\n");
717 }
718 #endif
719 }
720
721 SEND_FAILED:
722 RESPONSE_FAILED:
723 TLS_FAILED:
724 ;
725 /* Clear down of the TLS, SMTP and TCP layers on error is handled below. */
726
727
728 /* Failure to accept HELO is cached; this blocks the whole domain for all
729 senders. I/O errors and defer responses are not cached. */
730
731 if (!done)
732 {
733 *failure_ptr = US"mail"; /* At or before MAIL */
734 if (errno == 0 && responsebuffer[0] == '5')
735 {
736 setflag(addr, af_verify_nsfail);
737 new_domain_record.result = ccache_reject;
738 }
739 }
740
741 /* If we haven't authenticated, but are required to, give up. */
742 /* Try to AUTH */
743
744 else done = smtp_auth(responsebuffer, sizeof(responsebuffer),
745 addr, host, ob, esmtp, &inblock, &outblock) == OK &&
746
747 /* Copy AUTH info for logging */
748 ( (addr->authenticator = client_authenticator),
749 (addr->auth_id = client_authenticated_id),
750
751 /* Build a mail-AUTH string (re-using responsebuffer for convenience */
752 !smtp_mail_auth_str(responsebuffer, sizeof(responsebuffer), addr, ob)
753 ) &&
754
755 ( (addr->auth_sndr = client_authenticated_sender),
756
757 /* Send the MAIL command */
758 (smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>%s\r\n",
759 from_address, responsebuffer) >= 0)
760 ) &&
761
762 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
763 '2', callout);
764
765 /* If the host does not accept MAIL FROM:<>, arrange to cache this
766 information, but again, don't record anything for an I/O error or a defer. Do
767 not cache rejections of MAIL when a non-empty sender has been used, because
768 that blocks the whole domain for all senders. */
769
770 if (!done)
771 {
772 *failure_ptr = US"mail"; /* At or before MAIL */
773 if (errno == 0 && responsebuffer[0] == '5')
774 {
775 setflag(addr, af_verify_nsfail);
776 if (from_address[0] == 0)
777 new_domain_record.result = ccache_reject_mfnull;
778 }
779 }
780
781 /* Otherwise, proceed to check a "random" address (if required), then the
782 given address, and the postmaster address (if required). Between each check,
783 issue RSET, because some servers accept only one recipient after MAIL
784 FROM:<>.
785
786 Before doing this, set the result in the domain cache record to "accept",
787 unless its previous value was ccache_reject_mfnull. In that case, the domain
788 rejects MAIL FROM:<> and we want to continue to remember that. When that is
789 the case, we have got here only in the case of a recipient verification with
790 a non-null sender. */
791
792 else
793 {
794 new_domain_record.result =
795 (old_domain_cache_result == ccache_reject_mfnull)?
796 ccache_reject_mfnull: ccache_accept;
797
798 /* Do the random local part check first */
799
800 if (random_local_part != NULL)
801 {
802 uschar randombuffer[1024];
803 BOOL random_ok =
804 smtp_write_command(&outblock, FALSE,
805 "RCPT TO:<%.1000s@%.1000s>\r\n", random_local_part,
806 addr->domain) >= 0 &&
807 smtp_read_response(&inblock, randombuffer,
808 sizeof(randombuffer), '2', callout);
809
810 /* Remember when we last did a random test */
811
812 new_domain_record.random_stamp = time(NULL);
813
814 /* If accepted, we aren't going to do any further tests below. */
815
816 if (random_ok)
817 {
818 new_domain_record.random_result = ccache_accept;
819 }
820
821 /* Otherwise, cache a real negative response, and get back to the right
822 state to send RCPT. Unless there's some problem such as a dropped
823 connection, we expect to succeed, because the commands succeeded above. */
824
825 else if (errno == 0)
826 {
827 if (randombuffer[0] == '5')
828 new_domain_record.random_result = ccache_reject;
829
830 done =
831 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
832 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
833 '2', callout) &&
834
835 smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>\r\n",
836 from_address) >= 0 &&
837 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
838 '2', callout);
839 }
840 else done = FALSE; /* Some timeout/connection problem */
841 } /* Random check */
842
843 /* If the host is accepting all local parts, as determined by the "random"
844 check, we don't need to waste time doing any further checking. */
845
846 if (new_domain_record.random_result != ccache_accept && done)
847 {
848 /* Get the rcpt_include_affixes flag from the transport if there is one,
849 but assume FALSE if there is not. */
850
851 done =
852 smtp_write_command(&outblock, FALSE, "RCPT TO:<%.1000s>\r\n",
853 transport_rcpt_address(addr,
854 (addr->transport == NULL)? FALSE :
855 addr->transport->rcpt_include_affixes)) >= 0 &&
856 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
857 '2', callout);
858
859 if (done)
860 new_address_record.result = ccache_accept;
861 else if (errno == 0 && responsebuffer[0] == '5')
862 {
863 *failure_ptr = US"recipient";
864 new_address_record.result = ccache_reject;
865 }
866
867 /* Do postmaster check if requested; if a full check is required, we
868 check for RCPT TO:<postmaster> (no domain) in accordance with RFC 821. */
869
870 if (done && pm_mailfrom != NULL)
871 {
872 /*XXX not suitable for cutthrough - sequencing problems */
873 cutthrough_delivery= FALSE;
874 HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of postmaster verify\n");
875
876 done =
877 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
878 smtp_read_response(&inblock, responsebuffer,
879 sizeof(responsebuffer), '2', callout) &&
880
881 smtp_write_command(&outblock, FALSE,
882 "MAIL FROM:<%s>\r\n", pm_mailfrom) >= 0 &&
883 smtp_read_response(&inblock, responsebuffer,
884 sizeof(responsebuffer), '2', callout) &&
885
886 /* First try using the current domain */
887
888 ((
889 smtp_write_command(&outblock, FALSE,
890 "RCPT TO:<postmaster@%.1000s>\r\n", addr->domain) >= 0 &&
891 smtp_read_response(&inblock, responsebuffer,
892 sizeof(responsebuffer), '2', callout)
893 )
894
895 ||
896
897 /* If that doesn't work, and a full check is requested,
898 try without the domain. */
899
900 (
901 (options & vopt_callout_fullpm) != 0 &&
902 smtp_write_command(&outblock, FALSE,
903 "RCPT TO:<postmaster>\r\n") >= 0 &&
904 smtp_read_response(&inblock, responsebuffer,
905 sizeof(responsebuffer), '2', callout)
906 ));
907
908 /* Sort out the cache record */
909
910 new_domain_record.postmaster_stamp = time(NULL);
911
912 if (done)
913 new_domain_record.postmaster_result = ccache_accept;
914 else if (errno == 0 && responsebuffer[0] == '5')
915 {
916 *failure_ptr = US"postmaster";
917 setflag(addr, af_verify_pmfail);
918 new_domain_record.postmaster_result = ccache_reject;
919 }
920 }
921 } /* Random not accepted */
922 } /* MAIL FROM: accepted */
923
924 /* For any failure of the main check, other than a negative response, we just
925 close the connection and carry on. We can identify a negative response by the
926 fact that errno is zero. For I/O errors it will be non-zero
927
928 Set up different error texts for logging and for sending back to the caller
929 as an SMTP response. Log in all cases, using a one-line format. For sender
930 callouts, give a full response to the caller, but for recipient callouts,
931 don't give the IP address because this may be an internal host whose identity
932 is not to be widely broadcast. */
933
934 if (!done)
935 {
936 if (errno == ETIMEDOUT)
937 {
938 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
939 send_quit = FALSE;
940 }
941 else if (errno == 0)
942 {
943 if (*responsebuffer == 0) Ustrcpy(responsebuffer, US"connection dropped");
944
945 addr->message =
946 string_sprintf("response to \"%s\" from %s [%s] was: %s",
947 big_buffer, host->name, host->address,
948 string_printing(responsebuffer));
949
950 addr->user_message = is_recipient?
951 string_sprintf("Callout verification failed:\n%s", responsebuffer)
952 :
953 string_sprintf("Called: %s\nSent: %s\nResponse: %s",
954 host->address, big_buffer, responsebuffer);
955
956 /* Hard rejection ends the process */
957
958 if (responsebuffer[0] == '5') /* Address rejected */
959 {
960 yield = FAIL;
961 done = TRUE;
962 }
963 }
964 }
965
966 /* End the SMTP conversation and close the connection. */
967
968 /* Cutthrough - on a successfull connect and recipient-verify with use-sender
969 and we have no cutthrough conn so far
970 here is where we want to leave the conn open */
971 if ( cutthrough_delivery
972 && done
973 && yield == OK
974 && (options & (vopt_callout_recipsender|vopt_callout_recippmaster)) == vopt_callout_recipsender
975 && !random_local_part
976 && !pm_mailfrom
977 && cutthrough_fd < 0
978 )
979 {
980 cutthrough_fd= outblock.sock; /* We assume no buffer in use in the outblock */
981 cutthrough_addr = *addr; /* Save the address_item for later logging */
982 cutthrough_addr.next = NULL;
983 cutthrough_addr.host_used = store_get(sizeof(host_item));
984 cutthrough_addr.host_used->name = host->name;
985 cutthrough_addr.host_used->address = host->address;
986 cutthrough_addr.host_used->port = port;
987 if (addr->parent)
988 *(cutthrough_addr.parent = store_get(sizeof(address_item)))= *addr->parent;
989 ctblock.buffer = ctbuffer;
990 ctblock.buffersize = sizeof(ctbuffer);
991 ctblock.ptr = ctbuffer;
992 /* ctblock.cmd_count = 0; ctblock.authenticating = FALSE; */
993 ctblock.sock = cutthrough_fd;
994 }
995 else
996 {
997 /* Ensure no cutthrough on multiple address verifies */
998 if (options & vopt_callout_recipsender)
999 cancel_cutthrough_connection("multiple verify calls");
1000 if (send_quit) (void)smtp_write_command(&outblock, FALSE, "QUIT\r\n");
1001
1002 #ifdef SUPPORT_TLS
1003 tls_close(FALSE, TRUE);
1004 #endif
1005 (void)close(inblock.sock);
1006 }
1007
1008 } /* Loop through all hosts, while !done */
1009 }
1010
1011 /* If we get here with done == TRUE, a successful callout happened, and yield
1012 will be set OK or FAIL according to the response to the RCPT command.
1013 Otherwise, we looped through the hosts but couldn't complete the business.
1014 However, there may be domain-specific information to cache in both cases.
1015
1016 The value of the result field in the new_domain record is ccache_unknown if
1017 there was an error before or with MAIL FROM:, and errno was not zero,
1018 implying some kind of I/O error. We don't want to write the cache in that case.
1019 Otherwise the value is ccache_accept, ccache_reject, or ccache_reject_mfnull. */
1020
1021 if (!callout_no_cache && new_domain_record.result != ccache_unknown)
1022 {
1023 if ((dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE))
1024 == NULL)
1025 {
1026 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
1027 }
1028 else
1029 {
1030 (void)dbfn_write(dbm_file, addr->domain, &new_domain_record,
1031 (int)sizeof(dbdata_callout_cache));
1032 HDEBUG(D_verify) debug_printf("wrote callout cache domain record:\n"
1033 " result=%d postmaster=%d random=%d\n",
1034 new_domain_record.result,
1035 new_domain_record.postmaster_result,
1036 new_domain_record.random_result);
1037 }
1038 }
1039
1040 /* If a definite result was obtained for the callout, cache it unless caching
1041 is disabled. */
1042
1043 if (done)
1044 {
1045 if (!callout_no_cache && new_address_record.result != ccache_unknown)
1046 {
1047 if (dbm_file == NULL)
1048 dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE);
1049 if (dbm_file == NULL)
1050 {
1051 HDEBUG(D_verify) debug_printf("no callout cache available\n");
1052 }
1053 else
1054 {
1055 (void)dbfn_write(dbm_file, address_key, &new_address_record,
1056 (int)sizeof(dbdata_callout_cache_address));
1057 HDEBUG(D_verify) debug_printf("wrote %s callout cache address record\n",
1058 (new_address_record.result == ccache_accept)? "positive" : "negative");
1059 }
1060 }
1061 } /* done */
1062
1063 /* Failure to connect to any host, or any response other than 2xx or 5xx is a
1064 temporary error. If there was only one host, and a response was received, leave
1065 it alone if supplying details. Otherwise, give a generic response. */
1066
1067 else /* !done */
1068 {
1069 uschar *dullmsg = string_sprintf("Could not complete %s verify callout",
1070 is_recipient? "recipient" : "sender");
1071 yield = DEFER;
1072
1073 if (host_list->next != NULL || addr->message == NULL) addr->message = dullmsg;
1074
1075 addr->user_message = (!smtp_return_error_details)? dullmsg :
1076 string_sprintf("%s for <%s>.\n"
1077 "The mail server(s) for the domain may be temporarily unreachable, or\n"
1078 "they may be permanently unreachable from this server. In the latter case,\n%s",
1079 dullmsg, addr->address,
1080 is_recipient?
1081 "the address will never be accepted."
1082 :
1083 "you need to change the address or create an MX record for its domain\n"
1084 "if it is supposed to be generally accessible from the Internet.\n"
1085 "Talk to your mail administrator for details.");
1086
1087 /* Force a specific error code */
1088
1089 addr->basic_errno = ERRNO_CALLOUTDEFER;
1090 }
1091
1092 /* Come here from within the cache-reading code on fast-track exit. */
1093
1094 END_CALLOUT:
1095 if (dbm_file != NULL) dbfn_close(dbm_file);
1096 return yield;
1097 }
1098
1099
1100
1101 /* Called after recipient-acl to get a cutthrough connection open when
1102 one was requested and a recipient-verify wasn't subsequently done.
1103 */
1104 void
1105 open_cutthrough_connection( address_item * addr )
1106 {
1107 address_item addr2;
1108
1109 /* Use a recipient-verify-callout to set up the cutthrough connection. */
1110 /* We must use a copy of the address for verification, because it might
1111 get rewritten. */
1112
1113 addr2 = *addr;
1114 HDEBUG(D_acl) debug_printf("----------- start cutthrough setup ------------\n");
1115 (void) verify_address(&addr2, NULL,
1116 vopt_is_recipient | vopt_callout_recipsender | vopt_callout_no_cache,
1117 CUTTHROUGH_CMD_TIMEOUT, -1, -1,
1118 NULL, NULL, NULL);
1119 HDEBUG(D_acl) debug_printf("----------- end cutthrough setup ------------\n");
1120 return;
1121 }
1122
1123
1124
1125 /* Send given number of bytes from the buffer */
1126 static BOOL
1127 cutthrough_send(int n)
1128 {
1129 if(cutthrough_fd < 0)
1130 return TRUE;
1131
1132 if(
1133 #ifdef SUPPORT_TLS
1134 (tls_out.active == cutthrough_fd) ? tls_write(FALSE, ctblock.buffer, n) :
1135 #endif
1136 send(cutthrough_fd, ctblock.buffer, n, 0) > 0
1137 )
1138 {
1139 transport_count += n;
1140 ctblock.ptr= ctblock.buffer;
1141 return TRUE;
1142 }
1143
1144 HDEBUG(D_transport|D_acl) debug_printf("cutthrough_send failed: %s\n", strerror(errno));
1145 return FALSE;
1146 }
1147
1148
1149
1150 static BOOL
1151 _cutthrough_puts(uschar * cp, int n)
1152 {
1153 while(n--)
1154 {
1155 if(ctblock.ptr >= ctblock.buffer+ctblock.buffersize)
1156 if(!cutthrough_send(ctblock.buffersize))
1157 return FALSE;
1158
1159 *ctblock.ptr++ = *cp++;
1160 }
1161 return TRUE;
1162 }
1163
1164 /* Buffered output of counted data block. Return boolean success */
1165 BOOL
1166 cutthrough_puts(uschar * cp, int n)
1167 {
1168 if (cutthrough_fd < 0) return TRUE;
1169 if (_cutthrough_puts(cp, n)) return TRUE;
1170 cancel_cutthrough_connection("transmit failed");
1171 return FALSE;
1172 }
1173
1174
1175 static BOOL
1176 _cutthrough_flush_send( void )
1177 {
1178 int n= ctblock.ptr-ctblock.buffer;
1179
1180 if(n>0)
1181 if(!cutthrough_send(n))
1182 return FALSE;
1183 return TRUE;
1184 }
1185
1186
1187 /* Send out any bufferred output. Return boolean success. */
1188 BOOL
1189 cutthrough_flush_send( void )
1190 {
1191 if (_cutthrough_flush_send()) return TRUE;
1192 cancel_cutthrough_connection("transmit failed");
1193 return FALSE;
1194 }
1195
1196
1197 BOOL
1198 cutthrough_put_nl( void )
1199 {
1200 return cutthrough_puts(US"\r\n", 2);
1201 }
1202
1203
1204 /* Get and check response from cutthrough target */
1205 static uschar
1206 cutthrough_response(char expect, uschar ** copy)
1207 {
1208 smtp_inblock inblock;
1209 uschar inbuffer[4096];
1210 uschar responsebuffer[4096];
1211
1212 inblock.buffer = inbuffer;
1213 inblock.buffersize = sizeof(inbuffer);
1214 inblock.ptr = inbuffer;
1215 inblock.ptrend = inbuffer;
1216 inblock.sock = cutthrough_fd;
1217 /* this relies on (inblock.sock == tls_out.active) */
1218 if(!smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer), expect, CUTTHROUGH_DATA_TIMEOUT))
1219 cancel_cutthrough_connection("target timeout on read");
1220
1221 if(copy != NULL)
1222 {
1223 uschar * cp;
1224 *copy= cp= string_copy(responsebuffer);
1225 /* Trim the trailing end of line */
1226 cp += Ustrlen(responsebuffer);
1227 if(cp > *copy && cp[-1] == '\n') *--cp = '\0';
1228 if(cp > *copy && cp[-1] == '\r') *--cp = '\0';
1229 }
1230
1231 return responsebuffer[0];
1232 }
1233
1234
1235 /* Negotiate dataphase with the cutthrough target, returning success boolean */
1236 BOOL
1237 cutthrough_predata( void )
1238 {
1239 if(cutthrough_fd < 0)
1240 return FALSE;
1241
1242 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> DATA\n");
1243 cutthrough_puts(US"DATA\r\n", 6);
1244 cutthrough_flush_send();
1245
1246 /* Assume nothing buffered. If it was it gets ignored. */
1247 return cutthrough_response('3', NULL) == '3';
1248 }
1249
1250
1251 /* fd and use_crlf args only to match write_chunk() */
1252 static BOOL
1253 cutthrough_write_chunk(int fd, uschar * s, int len, BOOL use_crlf)
1254 {
1255 uschar * s2;
1256 while(s && (s2 = Ustrchr(s, '\n')))
1257 {
1258 if(!cutthrough_puts(s, s2-s) || !cutthrough_put_nl())
1259 return FALSE;
1260 s = s2+1;
1261 }
1262 return TRUE;
1263 }
1264
1265
1266 /* Buffered send of headers. Return success boolean. */
1267 /* Expands newlines to wire format (CR,NL). */
1268 /* Also sends header-terminating blank line. */
1269 BOOL
1270 cutthrough_headers_send( void )
1271 {
1272 if(cutthrough_fd < 0)
1273 return FALSE;
1274
1275 /* We share a routine with the mainline transport to handle header add/remove/rewrites,
1276 but having a separate buffered-output function (for now)
1277 */
1278 HDEBUG(D_acl) debug_printf("----------- start cutthrough headers send -----------\n");
1279
1280 if (!transport_headers_send(&cutthrough_addr, cutthrough_fd,
1281 cutthrough_addr.transport->add_headers, cutthrough_addr.transport->remove_headers,
1282 &cutthrough_write_chunk, TRUE,
1283 cutthrough_addr.transport->rewrite_rules, cutthrough_addr.transport->rewrite_existflags))
1284 return FALSE;
1285
1286 HDEBUG(D_acl) debug_printf("----------- done cutthrough headers send ------------\n");
1287 return TRUE;
1288 }
1289
1290
1291 static void
1292 close_cutthrough_connection( const char * why )
1293 {
1294 if(cutthrough_fd >= 0)
1295 {
1296 /* We could be sending this after a bunch of data, but that is ok as
1297 the only way to cancel the transfer in dataphase is to drop the tcp
1298 conn before the final dot.
1299 */
1300 ctblock.ptr = ctbuffer;
1301 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> QUIT\n");
1302 _cutthrough_puts(US"QUIT\r\n", 6); /* avoid recursion */
1303 _cutthrough_flush_send();
1304 /* No wait for response */
1305
1306 #ifdef SUPPORT_TLS
1307 tls_close(FALSE, TRUE);
1308 #endif
1309 (void)close(cutthrough_fd);
1310 cutthrough_fd= -1;
1311 HDEBUG(D_acl) debug_printf("----------- cutthrough shutdown (%s) ------------\n", why);
1312 }
1313 ctblock.ptr = ctbuffer;
1314 }
1315
1316 void
1317 cancel_cutthrough_connection( const char * why )
1318 {
1319 close_cutthrough_connection(why);
1320 cutthrough_delivery= FALSE;
1321 }
1322
1323
1324
1325
1326 /* Have senders final-dot. Send one to cutthrough target, and grab the response.
1327 Log an OK response as a transmission.
1328 Close the connection.
1329 Return smtp response-class digit.
1330 */
1331 uschar *
1332 cutthrough_finaldot( void )
1333 {
1334 HDEBUG(D_transport|D_acl|D_v) debug_printf(" SMTP>> .\n");
1335
1336 /* Assume data finshed with new-line */
1337 if(!cutthrough_puts(US".", 1) || !cutthrough_put_nl() || !cutthrough_flush_send())
1338 return cutthrough_addr.message;
1339
1340 switch(cutthrough_response('2', &cutthrough_addr.message))
1341 {
1342 case '2':
1343 delivery_log(LOG_MAIN, &cutthrough_addr, (int)'>', NULL);
1344 close_cutthrough_connection("delivered");
1345 break;
1346
1347 case '4':
1348 delivery_log(LOG_MAIN, &cutthrough_addr, 0, US"tmp-reject from cutthrough after DATA:");
1349 break;
1350
1351 case '5':
1352 delivery_log(LOG_MAIN|LOG_REJECT, &cutthrough_addr, 0, US"rejected after DATA:");
1353 break;
1354
1355 default:
1356 break;
1357 }
1358 return cutthrough_addr.message;
1359 }
1360
1361
1362
1363 /*************************************************
1364 * Copy error to toplevel address *
1365 *************************************************/
1366
1367 /* This function is used when a verify fails or defers, to ensure that the
1368 failure or defer information is in the original toplevel address. This applies
1369 when an address is redirected to a single new address, and the failure or
1370 deferral happens to the child address.
1371
1372 Arguments:
1373 vaddr the verify address item
1374 addr the final address item
1375 yield FAIL or DEFER
1376
1377 Returns: the value of YIELD
1378 */
1379
1380 static int
1381 copy_error(address_item *vaddr, address_item *addr, int yield)
1382 {
1383 if (addr != vaddr)
1384 {
1385 vaddr->message = addr->message;
1386 vaddr->user_message = addr->user_message;
1387 vaddr->basic_errno = addr->basic_errno;
1388 vaddr->more_errno = addr->more_errno;
1389 vaddr->p.address_data = addr->p.address_data;
1390 copyflag(vaddr, addr, af_pass_message);
1391 }
1392 return yield;
1393 }
1394
1395
1396
1397
1398 /**************************************************
1399 * printf that automatically handles TLS if needed *
1400 ***************************************************/
1401
1402 /* This function is used by verify_address() as a substitute for all fprintf()
1403 calls; a direct fprintf() will not produce output in a TLS SMTP session, such
1404 as a response to an EXPN command. smtp_in.c makes smtp_printf available but
1405 that assumes that we always use the smtp_out FILE* when not using TLS or the
1406 ssl buffer when we are. Instead we take a FILE* parameter and check to see if
1407 that is smtp_out; if so, smtp_printf() with TLS support, otherwise regular
1408 fprintf().
1409
1410 Arguments:
1411 f the candidate FILE* to write to
1412 format format string
1413 ... optional arguments
1414
1415 Returns:
1416 nothing
1417 */
1418
1419 static void PRINTF_FUNCTION(2,3)
1420 respond_printf(FILE *f, const char *format, ...)
1421 {
1422 va_list ap;
1423
1424 va_start(ap, format);
1425 if (smtp_out && (f == smtp_out))
1426 smtp_vprintf(format, ap);
1427 else
1428 vfprintf(f, format, ap);
1429 va_end(ap);
1430 }
1431
1432
1433
1434 /*************************************************
1435 * Verify an email address *
1436 *************************************************/
1437
1438 /* This function is used both for verification (-bv and at other times) and
1439 address testing (-bt), which is indicated by address_test_mode being set.
1440
1441 Arguments:
1442 vaddr contains the address to verify; the next field in this block
1443 must be NULL
1444 f if not NULL, write the result to this file
1445 options various option bits:
1446 vopt_fake_sender => this sender verify is not for the real
1447 sender (it was verify=sender=xxxx or an address from a
1448 header line) - rewriting must not change sender_address
1449 vopt_is_recipient => this is a recipient address, otherwise
1450 it's a sender address - this affects qualification and
1451 rewriting and messages from callouts
1452 vopt_qualify => qualify an unqualified address; else error
1453 vopt_expn => called from SMTP EXPN command
1454 vopt_success_on_redirect => when a new address is generated
1455 the verification instantly succeeds
1456
1457 These ones are used by do_callout() -- the options variable
1458 is passed to it.
1459
1460 vopt_callout_fullpm => if postmaster check, do full one
1461 vopt_callout_no_cache => don't use callout cache
1462 vopt_callout_random => do the "random" thing
1463 vopt_callout_recipsender => use real sender for recipient
1464 vopt_callout_recippmaster => use postmaster for recipient
1465
1466 callout if > 0, specifies that callout is required, and gives timeout
1467 for individual commands
1468 callout_overall if > 0, gives overall timeout for the callout function;
1469 if < 0, a default is used (see do_callout())
1470 callout_connect the connection timeout for callouts
1471 se_mailfrom when callout is requested to verify a sender, use this
1472 in MAIL FROM; NULL => ""
1473 pm_mailfrom when callout is requested, if non-NULL, do the postmaster
1474 thing and use this as the sender address (may be "")
1475
1476 routed if not NULL, set TRUE if routing succeeded, so we can
1477 distinguish between routing failed and callout failed
1478
1479 Returns: OK address verified
1480 FAIL address failed to verify
1481 DEFER can't tell at present
1482 */
1483
1484 int
1485 verify_address(address_item *vaddr, FILE *f, int options, int callout,
1486 int callout_overall, int callout_connect, uschar *se_mailfrom,
1487 uschar *pm_mailfrom, BOOL *routed)
1488 {
1489 BOOL allok = TRUE;
1490 BOOL full_info = (f == NULL)? FALSE : (debug_selector != 0);
1491 BOOL is_recipient = (options & vopt_is_recipient) != 0;
1492 BOOL expn = (options & vopt_expn) != 0;
1493 BOOL success_on_redirect = (options & vopt_success_on_redirect) != 0;
1494 int i;
1495 int yield = OK;
1496 int verify_type = expn? v_expn :
1497 address_test_mode? v_none :
1498 is_recipient? v_recipient : v_sender;
1499 address_item *addr_list;
1500 address_item *addr_new = NULL;
1501 address_item *addr_remote = NULL;
1502 address_item *addr_local = NULL;
1503 address_item *addr_succeed = NULL;
1504 uschar **failure_ptr = is_recipient?
1505 &recipient_verify_failure : &sender_verify_failure;
1506 uschar *ko_prefix, *cr;
1507 uschar *address = vaddr->address;
1508 uschar *save_sender;
1509 uschar null_sender[] = { 0 }; /* Ensure writeable memory */
1510
1511 /* Clear, just in case */
1512
1513 *failure_ptr = NULL;
1514
1515 /* Set up a prefix and suffix for error message which allow us to use the same
1516 output statements both in EXPN mode (where an SMTP response is needed) and when
1517 debugging with an output file. */
1518
1519 if (expn)
1520 {
1521 ko_prefix = US"553 ";
1522 cr = US"\r";
1523 }
1524 else ko_prefix = cr = US"";
1525
1526 /* Add qualify domain if permitted; otherwise an unqualified address fails. */
1527
1528 if (parse_find_at(address) == NULL)
1529 {
1530 if ((options & vopt_qualify) == 0)
1531 {
1532 if (f != NULL)
1533 respond_printf(f, "%sA domain is required for \"%s\"%s\n",
1534 ko_prefix, address, cr);
1535 *failure_ptr = US"qualify";
1536 return FAIL;
1537 }
1538 address = rewrite_address_qualify(address, is_recipient);
1539 }
1540
1541 DEBUG(D_verify)
1542 {
1543 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1544 debug_printf("%s %s\n", address_test_mode? "Testing" : "Verifying", address);
1545 }
1546
1547 /* Rewrite and report on it. Clear the domain and local part caches - these
1548 may have been set by domains and local part tests during an ACL. */
1549
1550 if (global_rewrite_rules != NULL)
1551 {
1552 uschar *old = address;
1553 address = rewrite_address(address, is_recipient, FALSE,
1554 global_rewrite_rules, rewrite_existflags);
1555 if (address != old)
1556 {
1557 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->localpart_cache[i] = 0;
1558 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->domain_cache[i] = 0;
1559 if (f != NULL && !expn) fprintf(f, "Address rewritten as: %s\n", address);
1560 }
1561 }
1562
1563 /* If this is the real sender address, we must update sender_address at
1564 this point, because it may be referred to in the routers. */
1565
1566 if ((options & (vopt_fake_sender|vopt_is_recipient)) == 0)
1567 sender_address = address;
1568
1569 /* If the address was rewritten to <> no verification can be done, and we have
1570 to return OK. This rewriting is permitted only for sender addresses; for other
1571 addresses, such rewriting fails. */
1572
1573 if (address[0] == 0) return OK;
1574
1575 /* Flip the legacy TLS-related variables over to the outbound set in case
1576 they're used in the context of a transport used by verification. Reset them
1577 at exit from this routine. */
1578
1579 tls_modify_variables(&tls_out);
1580
1581 /* Save a copy of the sender address for re-instating if we change it to <>
1582 while verifying a sender address (a nice bit of self-reference there). */
1583
1584 save_sender = sender_address;
1585
1586 /* Update the address structure with the possibly qualified and rewritten
1587 address. Set it up as the starting address on the chain of new addresses. */
1588
1589 vaddr->address = address;
1590 addr_new = vaddr;
1591
1592 /* We need a loop, because an address can generate new addresses. We must also
1593 cope with generated pipes and files at the top level. (See also the code and
1594 comment in deliver.c.) However, it is usually the case that the router for
1595 user's .forward files has its verify flag turned off.
1596
1597 If an address generates more than one child, the loop is used only when
1598 full_info is set, and this can only be set locally. Remote enquiries just get
1599 information about the top level address, not anything that it generated. */
1600
1601 while (addr_new != NULL)
1602 {
1603 int rc;
1604 address_item *addr = addr_new;
1605
1606 addr_new = addr->next;
1607 addr->next = NULL;
1608
1609 DEBUG(D_verify)
1610 {
1611 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1612 debug_printf("Considering %s\n", addr->address);
1613 }
1614
1615 /* Handle generated pipe, file or reply addresses. We don't get these
1616 when handling EXPN, as it does only one level of expansion. */
1617
1618 if (testflag(addr, af_pfr))
1619 {
1620 allok = FALSE;
1621 if (f != NULL)
1622 {
1623 BOOL allow;
1624
1625 if (addr->address[0] == '>')
1626 {
1627 allow = testflag(addr, af_allow_reply);
1628 fprintf(f, "%s -> mail %s", addr->parent->address, addr->address + 1);
1629 }
1630 else
1631 {
1632 allow = (addr->address[0] == '|')?
1633 testflag(addr, af_allow_pipe) : testflag(addr, af_allow_file);
1634 fprintf(f, "%s -> %s", addr->parent->address, addr->address);
1635 }
1636
1637 if (addr->basic_errno == ERRNO_BADTRANSPORT)
1638 fprintf(f, "\n*** Error in setting up pipe, file, or autoreply:\n"
1639 "%s\n", addr->message);
1640 else if (allow)
1641 fprintf(f, "\n transport = %s\n", addr->transport->name);
1642 else
1643 fprintf(f, " *** forbidden ***\n");
1644 }
1645 continue;
1646 }
1647
1648 /* Just in case some router parameter refers to it. */
1649
1650 return_path = (addr->p.errors_address != NULL)?
1651 addr->p.errors_address : sender_address;
1652
1653 /* Split the address into domain and local part, handling the %-hack if
1654 necessary, and then route it. While routing a sender address, set
1655 $sender_address to <> because that is what it will be if we were trying to
1656 send a bounce to the sender. */
1657
1658 if (routed != NULL) *routed = FALSE;
1659 if ((rc = deliver_split_address(addr)) == OK)
1660 {
1661 if (!is_recipient) sender_address = null_sender;
1662 rc = route_address(addr, &addr_local, &addr_remote, &addr_new,
1663 &addr_succeed, verify_type);
1664 sender_address = save_sender; /* Put back the real sender */
1665 }
1666
1667 /* If routing an address succeeded, set the flag that remembers, for use when
1668 an ACL cached a sender verify (in case a callout fails). Then if routing set
1669 up a list of hosts or the transport has a host list, and the callout option
1670 is set, and we aren't in a host checking run, do the callout verification,
1671 and set another flag that notes that a callout happened. */
1672
1673 if (rc == OK)
1674 {
1675 if (routed != NULL) *routed = TRUE;
1676 if (callout > 0)
1677 {
1678 host_item *host_list = addr->host_list;
1679
1680 /* Make up some data for use in the case where there is no remote
1681 transport. */
1682
1683 transport_feedback tf = {
1684 NULL, /* interface (=> any) */
1685 US"smtp", /* port */
1686 US"smtp", /* protocol */
1687 NULL, /* hosts */
1688 US"$smtp_active_hostname", /* helo_data */
1689 FALSE, /* hosts_override */
1690 FALSE, /* hosts_randomize */
1691 FALSE, /* gethostbyname */
1692 TRUE, /* qualify_single */
1693 FALSE /* search_parents */
1694 };
1695
1696 /* If verification yielded a remote transport, we want to use that
1697 transport's options, so as to mimic what would happen if we were really
1698 sending a message to this address. */
1699
1700 if (addr->transport != NULL && !addr->transport->info->local)
1701 {
1702 (void)(addr->transport->setup)(addr->transport, addr, &tf, 0, 0, NULL);
1703
1704 /* If the transport has hosts and the router does not, or if the
1705 transport is configured to override the router's hosts, we must build a
1706 host list of the transport's hosts, and find the IP addresses */
1707
1708 if (tf.hosts != NULL && (host_list == NULL || tf.hosts_override))
1709 {
1710 uschar *s;
1711 uschar *save_deliver_domain = deliver_domain;
1712 uschar *save_deliver_localpart = deliver_localpart;
1713
1714 host_list = NULL; /* Ignore the router's hosts */
1715
1716 deliver_domain = addr->domain;
1717 deliver_localpart = addr->local_part;
1718 s = expand_string(tf.hosts);
1719 deliver_domain = save_deliver_domain;
1720 deliver_localpart = save_deliver_localpart;
1721
1722 if (s == NULL)
1723 {
1724 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand list of hosts "
1725 "\"%s\" in %s transport for callout: %s", tf.hosts,
1726 addr->transport->name, expand_string_message);
1727 }
1728 else
1729 {
1730 int flags;
1731 uschar *canonical_name;
1732 host_item *host, *nexthost;
1733 host_build_hostlist(&host_list, s, tf.hosts_randomize);
1734
1735 /* Just ignore failures to find a host address. If we don't manage
1736 to find any addresses, the callout will defer. Note that more than
1737 one address may be found for a single host, which will result in
1738 additional host items being inserted into the chain. Hence we must
1739 save the next host first. */
1740
1741 flags = HOST_FIND_BY_A;
1742 if (tf.qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
1743 if (tf.search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
1744
1745 for (host = host_list; host != NULL; host = nexthost)
1746 {
1747 nexthost = host->next;
1748 if (tf.gethostbyname ||
1749 string_is_ip_address(host->name, NULL) != 0)
1750 (void)host_find_byname(host, NULL, flags, &canonical_name, TRUE);
1751 else
1752 {
1753 uschar * d_request = NULL, * d_require = NULL;
1754 if (Ustrcmp(addr->transport->driver_name, "smtp") == 0)
1755 {
1756 smtp_transport_options_block * ob =
1757 (smtp_transport_options_block *)
1758 addr->transport->options_block;
1759 d_request = ob->dnssec_request_domains;
1760 d_require = ob->dnssec_require_domains;
1761 }
1762
1763 (void)host_find_bydns(host, NULL, flags, NULL, NULL, NULL,
1764 d_request, d_require, &canonical_name, NULL);
1765 }
1766 }
1767 }
1768 }
1769 }
1770
1771 /* Can only do a callout if we have at least one host! If the callout
1772 fails, it will have set ${sender,recipient}_verify_failure. */
1773
1774 if (host_list != NULL)
1775 {
1776 HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n");
1777 if (host_checking && !host_checking_callout)
1778 {
1779 HDEBUG(D_verify)
1780 debug_printf("... callout omitted by default when host testing\n"
1781 "(Use -bhc if you want the callouts to happen.)\n");
1782 }
1783 else
1784 {
1785 #ifdef SUPPORT_TLS
1786 deliver_set_expansions(addr);
1787 #endif
1788 rc = do_callout(addr, host_list, &tf, callout, callout_overall,
1789 callout_connect, options, se_mailfrom, pm_mailfrom);
1790 }
1791 }
1792 else
1793 {
1794 HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor "
1795 "transport provided a host list\n");
1796 }
1797 }
1798 }
1799
1800 /* Otherwise, any failure is a routing failure */
1801
1802 else *failure_ptr = US"route";
1803
1804 /* A router may return REROUTED if it has set up a child address as a result
1805 of a change of domain name (typically from widening). In this case we always
1806 want to continue to verify the new child. */
1807
1808 if (rc == REROUTED) continue;
1809
1810 /* Handle hard failures */
1811
1812 if (rc == FAIL)
1813 {
1814 allok = FALSE;
1815 if (f != NULL)
1816 {
1817 address_item *p = addr->parent;
1818
1819 respond_printf(f, "%s%s %s", ko_prefix,
1820 full_info? addr->address : address,
1821 address_test_mode? "is undeliverable" : "failed to verify");
1822 if (!expn && admin_user)
1823 {
1824 if (addr->basic_errno > 0)
1825 respond_printf(f, ": %s", strerror(addr->basic_errno));
1826 if (addr->message != NULL)
1827 respond_printf(f, ": %s", addr->message);
1828 }
1829
1830 /* Show parents iff doing full info */
1831
1832 if (full_info) while (p != NULL)
1833 {
1834 respond_printf(f, "%s\n <-- %s", cr, p->address);
1835 p = p->parent;
1836 }
1837 respond_printf(f, "%s\n", cr);
1838 }
1839 cancel_cutthrough_connection("routing hard fail");
1840
1841 if (!full_info)
1842 {
1843 yield = copy_error(vaddr, addr, FAIL);
1844 goto out;
1845 }
1846 else yield = FAIL;
1847 }
1848
1849 /* Soft failure */
1850
1851 else if (rc == DEFER)
1852 {
1853 allok = FALSE;
1854 if (f != NULL)
1855 {
1856 address_item *p = addr->parent;
1857 respond_printf(f, "%s%s cannot be resolved at this time", ko_prefix,
1858 full_info? addr->address : address);
1859 if (!expn && admin_user)
1860 {
1861 if (addr->basic_errno > 0)
1862 respond_printf(f, ": %s", strerror(addr->basic_errno));
1863 if (addr->message != NULL)
1864 respond_printf(f, ": %s", addr->message);
1865 else if (addr->basic_errno <= 0)
1866 respond_printf(f, ": unknown error");
1867 }
1868
1869 /* Show parents iff doing full info */
1870
1871 if (full_info) while (p != NULL)
1872 {
1873 respond_printf(f, "%s\n <-- %s", cr, p->address);
1874 p = p->parent;
1875 }
1876 respond_printf(f, "%s\n", cr);
1877 }
1878 cancel_cutthrough_connection("routing soft fail");
1879
1880 if (!full_info)
1881 {
1882 yield = copy_error(vaddr, addr, DEFER);
1883 goto out;
1884 }
1885 else if (yield == OK) yield = DEFER;
1886 }
1887
1888 /* If we are handling EXPN, we do not want to continue to route beyond
1889 the top level (whose address is in "address"). */
1890
1891 else if (expn)
1892 {
1893 uschar *ok_prefix = US"250-";
1894 if (addr_new == NULL)
1895 {
1896 if (addr_local == NULL && addr_remote == NULL)
1897 respond_printf(f, "250 mail to <%s> is discarded\r\n", address);
1898 else
1899 respond_printf(f, "250 <%s>\r\n", address);
1900 }
1901 else while (addr_new != NULL)
1902 {
1903 address_item *addr2 = addr_new;
1904 addr_new = addr2->next;
1905 if (addr_new == NULL) ok_prefix = US"250 ";
1906 respond_printf(f, "%s<%s>\r\n", ok_prefix, addr2->address);
1907 }
1908 yield = OK;
1909 goto out;
1910 }
1911
1912 /* Successful routing other than EXPN. */
1913
1914 else
1915 {
1916 /* Handle successful routing when short info wanted. Otherwise continue for
1917 other (generated) addresses. Short info is the operational case. Full info
1918 can be requested only when debug_selector != 0 and a file is supplied.
1919
1920 There is a conflict between the use of aliasing as an alternate email
1921 address, and as a sort of mailing list. If an alias turns the incoming
1922 address into just one address (e.g. J.Caesar->jc44) you may well want to
1923 carry on verifying the generated address to ensure it is valid when
1924 checking incoming mail. If aliasing generates multiple addresses, you
1925 probably don't want to do this. Exim therefore treats the generation of
1926 just a single new address as a special case, and continues on to verify the
1927 generated address. */
1928
1929 if (!full_info && /* Stop if short info wanted AND */
1930 (((addr_new == NULL || /* No new address OR */
1931 addr_new->next != NULL || /* More than one new address OR */
1932 testflag(addr_new, af_pfr))) /* New address is pfr */
1933 || /* OR */
1934 (addr_new != NULL && /* At least one new address AND */
1935 success_on_redirect))) /* success_on_redirect is set */
1936 {
1937 if (f != NULL) fprintf(f, "%s %s\n", address,
1938 address_test_mode? "is deliverable" : "verified");
1939
1940 /* If we have carried on to verify a child address, we want the value
1941 of $address_data to be that of the child */
1942
1943 vaddr->p.address_data = addr->p.address_data;
1944 yield = OK;
1945 goto out;
1946 }
1947 }
1948 } /* Loop for generated addresses */
1949
1950 /* Display the full results of the successful routing, including any generated
1951 addresses. Control gets here only when full_info is set, which requires f not
1952 to be NULL, and this occurs only when a top-level verify is called with the
1953 debugging switch on.
1954
1955 If there are no local and no remote addresses, and there were no pipes, files,
1956 or autoreplies, and there were no errors or deferments, the message is to be
1957 discarded, usually because of the use of :blackhole: in an alias file. */
1958
1959 if (allok && addr_local == NULL && addr_remote == NULL)
1960 {
1961 fprintf(f, "mail to %s is discarded\n", address);
1962 goto out;
1963 }
1964
1965 for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++)
1966 {
1967 while (addr_list != NULL)
1968 {
1969 address_item *addr = addr_list;
1970 address_item *p = addr->parent;
1971 addr_list = addr->next;
1972
1973 fprintf(f, "%s", CS addr->address);
1974 #ifdef EXPERIMENTAL_SRS
1975 if(addr->p.srs_sender)
1976 fprintf(f, " [srs = %s]", addr->p.srs_sender);
1977 #endif
1978
1979 /* If the address is a duplicate, show something about it. */
1980
1981 if (!testflag(addr, af_pfr))
1982 {
1983 tree_node *tnode;
1984 if ((tnode = tree_search(tree_duplicates, addr->unique)) != NULL)
1985 fprintf(f, " [duplicate, would not be delivered]");
1986 else tree_add_duplicate(addr->unique, addr);
1987 }
1988
1989 /* Now show its parents */
1990
1991 while (p != NULL)
1992 {
1993 fprintf(f, "\n <-- %s", p->address);
1994 p = p->parent;
1995 }
1996 fprintf(f, "\n ");
1997
1998 /* Show router, and transport */
1999
2000 fprintf(f, "router = %s, ", addr->router->name);
2001 fprintf(f, "transport = %s\n", (addr->transport == NULL)? US"unset" :
2002 addr->transport->name);
2003
2004 /* Show any hosts that are set up by a router unless the transport
2005 is going to override them; fiddle a bit to get a nice format. */
2006
2007 if (addr->host_list != NULL && addr->transport != NULL &&
2008 !addr->transport->overrides_hosts)
2009 {
2010 host_item *h;
2011 int maxlen = 0;
2012 int maxaddlen = 0;
2013 for (h = addr->host_list; h != NULL; h = h->next)
2014 {
2015 int len = Ustrlen(h->name);
2016 if (len > maxlen) maxlen = len;
2017 len = (h->address != NULL)? Ustrlen(h->address) : 7;
2018 if (len > maxaddlen) maxaddlen = len;
2019 }
2020 for (h = addr->host_list; h != NULL; h = h->next)
2021 {
2022 int len = Ustrlen(h->name);
2023 fprintf(f, " host %s ", h->name);
2024 while (len++ < maxlen) fprintf(f, " ");
2025 if (h->address != NULL)
2026 {
2027 fprintf(f, "[%s] ", h->address);
2028 len = Ustrlen(h->address);
2029 }
2030 else if (!addr->transport->info->local) /* Omit [unknown] for local */
2031 {
2032 fprintf(f, "[unknown] ");
2033 len = 7;
2034 }
2035 else len = -3;
2036 while (len++ < maxaddlen) fprintf(f," ");
2037 if (h->mx >= 0) fprintf(f, "MX=%d", h->mx);
2038 if (h->port != PORT_NONE) fprintf(f, " port=%d", h->port);
2039 if (h->status == hstatus_unusable) fprintf(f, " ** unusable **");
2040 fprintf(f, "\n");
2041 }
2042 }
2043 }
2044 }
2045
2046 /* Yield will be DEFER or FAIL if any one address has, only for full_info (which is
2047 the -bv or -bt case). */
2048
2049 out:
2050 tls_modify_variables(&tls_in);
2051
2052 return yield;
2053 }
2054
2055
2056
2057
2058 /*************************************************
2059 * Check headers for syntax errors *
2060 *************************************************/
2061
2062 /* This function checks those header lines that contain addresses, and verifies
2063 that all the addresses therein are syntactially correct.
2064
2065 Arguments:
2066 msgptr where to put an error message
2067
2068 Returns: OK
2069 FAIL
2070 */
2071
2072 int
2073 verify_check_headers(uschar **msgptr)
2074 {
2075 header_line *h;
2076 uschar *colon, *s;
2077 int yield = OK;
2078
2079 for (h = header_list; h != NULL && yield == OK; h = h->next)
2080 {
2081 if (h->type != htype_from &&
2082 h->type != htype_reply_to &&
2083 h->type != htype_sender &&
2084 h->type != htype_to &&
2085 h->type != htype_cc &&
2086 h->type != htype_bcc)
2087 continue;
2088
2089 colon = Ustrchr(h->text, ':');
2090 s = colon + 1;
2091 while (isspace(*s)) s++;
2092
2093 /* Loop for multiple addresses in the header, enabling group syntax. Note
2094 that we have to reset this after the header has been scanned. */
2095
2096 parse_allow_group = TRUE;
2097
2098 while (*s != 0)
2099 {
2100 uschar *ss = parse_find_address_end(s, FALSE);
2101 uschar *recipient, *errmess;
2102 int terminator = *ss;
2103 int start, end, domain;
2104
2105 /* Temporarily terminate the string at this point, and extract the
2106 operative address within, allowing group syntax. */
2107
2108 *ss = 0;
2109 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2110 *ss = terminator;
2111
2112 /* Permit an unqualified address only if the message is local, or if the
2113 sending host is configured to be permitted to send them. */
2114
2115 if (recipient != NULL && domain == 0)
2116 {
2117 if (h->type == htype_from || h->type == htype_sender)
2118 {
2119 if (!allow_unqualified_sender) recipient = NULL;
2120 }
2121 else
2122 {
2123 if (!allow_unqualified_recipient) recipient = NULL;
2124 }
2125 if (recipient == NULL) errmess = US"unqualified address not permitted";
2126 }
2127
2128 /* It's an error if no address could be extracted, except for the special
2129 case of an empty address. */
2130
2131 if (recipient == NULL && Ustrcmp(errmess, "empty address") != 0)
2132 {
2133 uschar *verb = US"is";
2134 uschar *t = ss;
2135 uschar *tt = colon;
2136 int len;
2137
2138 /* Arrange not to include any white space at the end in the
2139 error message or the header name. */
2140
2141 while (t > s && isspace(t[-1])) t--;
2142 while (tt > h->text && isspace(tt[-1])) tt--;
2143
2144 /* Add the address that failed to the error message, since in a
2145 header with very many addresses it is sometimes hard to spot
2146 which one is at fault. However, limit the amount of address to
2147 quote - cases have been seen where, for example, a missing double
2148 quote in a humungous To: header creates an "address" that is longer
2149 than string_sprintf can handle. */
2150
2151 len = t - s;
2152 if (len > 1024)
2153 {
2154 len = 1024;
2155 verb = US"begins";
2156 }
2157
2158 *msgptr = string_printing(
2159 string_sprintf("%s: failing address in \"%.*s:\" header %s: %.*s",
2160 errmess, tt - h->text, h->text, verb, len, s));
2161
2162 yield = FAIL;
2163 break; /* Out of address loop */
2164 }
2165
2166 /* Advance to the next address */
2167
2168 s = ss + (terminator? 1:0);
2169 while (isspace(*s)) s++;
2170 } /* Next address */
2171
2172 parse_allow_group = FALSE;
2173 parse_found_group = FALSE;
2174 } /* Next header unless yield has been set FALSE */
2175
2176 return yield;
2177 }
2178
2179
2180 /*************************************************
2181 * Check header names for 8-bit characters *
2182 *************************************************/
2183
2184 /* This function checks for invalid charcters in header names. See
2185 RFC 5322, 2.2. and RFC 6532, 3.
2186
2187 Arguments:
2188 msgptr where to put an error message
2189
2190 Returns: OK
2191 FAIL
2192 */
2193
2194 int
2195 verify_check_header_names_ascii(uschar **msgptr)
2196 {
2197 header_line *h;
2198 uschar *colon, *s;
2199
2200 for (h = header_list; h != NULL; h = h->next)
2201 {
2202 colon = Ustrchr(h->text, ':');
2203 for(s = h->text; s < colon; s++)
2204 {
2205 if ((*s < 33) || (*s > 126))
2206 {
2207 *msgptr = string_sprintf("Invalid character in header \"%.*s\" found",
2208 colon - h->text, h->text);
2209 return FAIL;
2210 }
2211 }
2212 }
2213 return OK;
2214 }
2215
2216 /*************************************************
2217 * Check for blind recipients *
2218 *************************************************/
2219
2220 /* This function checks that every (envelope) recipient is mentioned in either
2221 the To: or Cc: header lines, thus detecting blind carbon copies.
2222
2223 There are two ways of scanning that could be used: either scan the header lines
2224 and tick off the recipients, or scan the recipients and check the header lines.
2225 The original proposed patch did the former, but I have chosen to do the latter,
2226 because (a) it requires no memory and (b) will use fewer resources when there
2227 are many addresses in To: and/or Cc: and only one or two envelope recipients.
2228
2229 Arguments: none
2230 Returns: OK if there are no blind recipients
2231 FAIL if there is at least one blind recipient
2232 */
2233
2234 int
2235 verify_check_notblind(void)
2236 {
2237 int i;
2238 for (i = 0; i < recipients_count; i++)
2239 {
2240 header_line *h;
2241 BOOL found = FALSE;
2242 uschar *address = recipients_list[i].address;
2243
2244 for (h = header_list; !found && h != NULL; h = h->next)
2245 {
2246 uschar *colon, *s;
2247
2248 if (h->type != htype_to && h->type != htype_cc) continue;
2249
2250 colon = Ustrchr(h->text, ':');
2251 s = colon + 1;
2252 while (isspace(*s)) s++;
2253
2254 /* Loop for multiple addresses in the header, enabling group syntax. Note
2255 that we have to reset this after the header has been scanned. */
2256
2257 parse_allow_group = TRUE;
2258
2259 while (*s != 0)
2260 {
2261 uschar *ss = parse_find_address_end(s, FALSE);
2262 uschar *recipient,*errmess;
2263 int terminator = *ss;
2264 int start, end, domain;
2265
2266 /* Temporarily terminate the string at this point, and extract the
2267 operative address within, allowing group syntax. */
2268
2269 *ss = 0;
2270 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
2271 *ss = terminator;
2272
2273 /* If we found a valid recipient that has a domain, compare it with the
2274 envelope recipient. Local parts are compared case-sensitively, domains
2275 case-insensitively. By comparing from the start with length "domain", we
2276 include the "@" at the end, which ensures that we are comparing the whole
2277 local part of each address. */
2278
2279 if (recipient != NULL && domain != 0)
2280 {
2281 found = Ustrncmp(recipient, address, domain) == 0 &&
2282 strcmpic(recipient + domain, address + domain) == 0;
2283 if (found) break;
2284 }
2285
2286 /* Advance to the next address */
2287
2288 s = ss + (terminator? 1:0);
2289 while (isspace(*s)) s++;
2290 } /* Next address */
2291
2292 parse_allow_group = FALSE;
2293 parse_found_group = FALSE;
2294 } /* Next header (if found is false) */
2295
2296 if (!found) return FAIL;
2297 } /* Next recipient */
2298
2299 return OK;
2300 }
2301
2302
2303
2304 /*************************************************
2305 * Find if verified sender *
2306 *************************************************/
2307
2308 /* Usually, just a single address is verified as the sender of the message.
2309 However, Exim can be made to verify other addresses as well (often related in
2310 some way), and this is useful in some environments. There may therefore be a
2311 chain of such addresses that have previously been tested. This function finds
2312 whether a given address is on the chain.
2313
2314 Arguments: the address to be verified
2315 Returns: pointer to an address item, or NULL
2316 */
2317
2318 address_item *
2319 verify_checked_sender(uschar *sender)
2320 {
2321 address_item *addr;
2322 for (addr = sender_verified_list; addr != NULL; addr = addr->next)
2323 if (Ustrcmp(sender, addr->address) == 0) break;
2324 return addr;
2325 }
2326
2327
2328
2329
2330
2331 /*************************************************
2332 * Get valid header address *
2333 *************************************************/
2334
2335 /* Scan the originator headers of the message, looking for an address that
2336 verifies successfully. RFC 822 says:
2337
2338 o The "Sender" field mailbox should be sent notices of
2339 any problems in transport or delivery of the original
2340 messages. If there is no "Sender" field, then the
2341 "From" field mailbox should be used.
2342
2343 o If the "Reply-To" field exists, then the reply should
2344 go to the addresses indicated in that field and not to
2345 the address(es) indicated in the "From" field.
2346
2347 So we check a Sender field if there is one, else a Reply_to field, else a From
2348 field. As some strange messages may have more than one of these fields,
2349 especially if they are resent- fields, check all of them if there is more than
2350 one.
2351
2352 Arguments:
2353 user_msgptr points to where to put a user error message
2354 log_msgptr points to where to put a log error message
2355 callout timeout for callout check (passed to verify_address())
2356 callout_overall overall callout timeout (ditto)
2357 callout_connect connect callout timeout (ditto)
2358 se_mailfrom mailfrom for verify; NULL => ""
2359 pm_mailfrom sender for pm callout check (passed to verify_address())
2360 options callout options (passed to verify_address())
2361 verrno where to put the address basic_errno
2362
2363 If log_msgptr is set to something without setting user_msgptr, the caller
2364 normally uses log_msgptr for both things.
2365
2366 Returns: result of the verification attempt: OK, FAIL, or DEFER;
2367 FAIL is given if no appropriate headers are found
2368 */
2369
2370 int
2371 verify_check_header_address(uschar **user_msgptr, uschar **log_msgptr,
2372 int callout, int callout_overall, int callout_connect, uschar *se_mailfrom,
2373 uschar *pm_mailfrom, int options, int *verrno)
2374 {
2375 static int header_types[] = { htype_sender, htype_reply_to, htype_from };
2376 BOOL done = FALSE;
2377 int yield = FAIL;
2378 int i;
2379
2380 for (i = 0; i < 3 && !done; i++)
2381 {
2382 header_line *h;
2383 for (h = header_list; h != NULL && !done; h = h->next)
2384 {
2385 int terminator, new_ok;
2386 uschar *s, *ss, *endname;
2387
2388 if (h->type != header_types[i]) continue;
2389 s = endname = Ustrchr(h->text, ':') + 1;
2390
2391 /* Scan the addresses in the header, enabling group syntax. Note that we
2392 have to reset this after the header has been scanned. */
2393
2394 parse_allow_group = TRUE;
2395
2396 while (*s != 0)
2397 {
2398 address_item *vaddr;
2399
2400 while (isspace(*s) || *s == ',') s++;
2401 if (*s == 0) break; /* End of header */
2402
2403 ss = parse_find_address_end(s, FALSE);
2404
2405 /* The terminator is a comma or end of header, but there may be white
2406 space preceding it (including newline for the last address). Move back
2407 past any white space so we can check against any cached envelope sender
2408 address verifications. */
2409
2410 while (isspace(ss[-1])) ss--;
2411 terminator = *ss;
2412 *ss = 0;
2413
2414 HDEBUG(D_verify) debug_printf("verifying %.*s header address %s\n",
2415 (int)(endname - h->text), h->text, s);
2416
2417 /* See if we have already verified this address as an envelope sender,
2418 and if so, use the previous answer. */
2419
2420 vaddr = verify_checked_sender(s);
2421
2422 if (vaddr != NULL && /* Previously checked */
2423 (callout <= 0 || /* No callout needed; OR */
2424 vaddr->special_action > 256)) /* Callout was done */
2425 {
2426 new_ok = vaddr->special_action & 255;
2427 HDEBUG(D_verify) debug_printf("previously checked as envelope sender\n");
2428 *ss = terminator; /* Restore shortened string */
2429 }
2430
2431 /* Otherwise we run the verification now. We must restore the shortened
2432 string before running the verification, so the headers are correct, in
2433 case there is any rewriting. */
2434
2435 else
2436 {
2437 int start, end, domain;
2438 uschar *address = parse_extract_address(s, log_msgptr, &start, &end,
2439 &domain, FALSE);
2440
2441 *ss = terminator;
2442
2443 /* If we found an empty address, just carry on with the next one, but
2444 kill the message. */
2445
2446 if (address == NULL && Ustrcmp(*log_msgptr, "empty address") == 0)
2447 {
2448 *log_msgptr = NULL;
2449 s = ss;
2450 continue;
2451 }
2452
2453 /* If verification failed because of a syntax error, fail this
2454 function, and ensure that the failing address gets added to the error
2455 message. */
2456
2457 if (address == NULL)
2458 {
2459 new_ok = FAIL;
2460 while (ss > s && isspace(ss[-1])) ss--;
2461 *log_msgptr = string_sprintf("syntax error in '%.*s' header when "
2462 "scanning for sender: %s in \"%.*s\"",
2463 endname - h->text, h->text, *log_msgptr, ss - s, s);
2464 yield = FAIL;
2465 done = TRUE;
2466 break;
2467 }
2468
2469 /* Else go ahead with the sender verification. But it isn't *the*
2470 sender of the message, so set vopt_fake_sender to stop sender_address
2471 being replaced after rewriting or qualification. */
2472
2473 else
2474 {
2475 vaddr = deliver_make_addr(address, FALSE);
2476 new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender,
2477 callout, callout_overall, callout_connect, se_mailfrom,
2478 pm_mailfrom, NULL);
2479 }
2480 }
2481
2482 /* We now have the result, either newly found, or cached. If we are
2483 giving out error details, set a specific user error. This means that the
2484 last of these will be returned to the user if all three fail. We do not
2485 set a log message - the generic one below will be used. */
2486
2487 if (new_ok != OK)
2488 {
2489 *verrno = vaddr->basic_errno;
2490 if (smtp_return_error_details)
2491 {
2492 *user_msgptr = string_sprintf("Rejected after DATA: "
2493 "could not verify \"%.*s\" header address\n%s: %s",
2494 endname - h->text, h->text, vaddr->address, vaddr->message);
2495 }
2496 }
2497
2498 /* Success or defer */
2499
2500 if (new_ok == OK)
2501 {
2502 yield = OK;
2503 done = TRUE;
2504 break;
2505 }
2506
2507 if (new_ok == DEFER) yield = DEFER;
2508
2509 /* Move on to any more addresses in the header */
2510
2511 s = ss;
2512 } /* Next address */
2513
2514 parse_allow_group = FALSE;
2515 parse_found_group = FALSE;
2516 } /* Next header, unless done */
2517 } /* Next header type unless done */
2518
2519 if (yield == FAIL && *log_msgptr == NULL)
2520 *log_msgptr = US"there is no valid sender in any header line";
2521
2522 if (yield == DEFER && *log_msgptr == NULL)
2523 *log_msgptr = US"all attempts to verify a sender in a header line deferred";
2524
2525 return yield;
2526 }
2527
2528
2529
2530
2531 /*************************************************
2532 * Get RFC 1413 identification *
2533 *************************************************/
2534
2535 /* Attempt to get an id from the sending machine via the RFC 1413 protocol. If
2536 the timeout is set to zero, then the query is not done. There may also be lists
2537 of hosts and nets which are exempt. To guard against malefactors sending
2538 non-printing characters which could, for example, disrupt a message's headers,
2539 make sure the string consists of printing characters only.
2540
2541 Argument:
2542 port the port to connect to; usually this is IDENT_PORT (113), but when
2543 running in the test harness with -bh a different value is used.
2544
2545 Returns: nothing
2546
2547 Side effect: any received ident value is put in sender_ident (NULL otherwise)
2548 */
2549
2550 void
2551 verify_get_ident(int port)
2552 {
2553 int sock, host_af, qlen;
2554 int received_sender_port, received_interface_port, n;
2555 uschar *p;
2556 uschar buffer[2048];
2557
2558 /* Default is no ident. Check whether we want to do an ident check for this
2559 host. */
2560
2561 sender_ident = NULL;
2562 if (rfc1413_query_timeout <= 0 || verify_check_host(&rfc1413_hosts) != OK)
2563 return;
2564
2565 DEBUG(D_ident) debug_printf("doing ident callback\n");
2566
2567 /* Set up a connection to the ident port of the remote host. Bind the local end
2568 to the incoming interface address. If the sender host address is an IPv6
2569 address, the incoming interface address will also be IPv6. */
2570
2571 host_af = (Ustrchr(sender_host_address, ':') == NULL)? AF_INET : AF_INET6;
2572 sock = ip_socket(SOCK_STREAM, host_af);
2573 if (sock < 0) return;
2574
2575 if (ip_bind(sock, host_af, interface_address, 0) < 0)
2576 {
2577 DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n",
2578 strerror(errno));
2579 goto END_OFF;
2580 }
2581
2582 if (ip_connect(sock, host_af, sender_host_address, port, rfc1413_query_timeout)
2583 < 0)
2584 {
2585 if (errno == ETIMEDOUT && (log_extra_selector & LX_ident_timeout) != 0)
2586 {
2587 log_write(0, LOG_MAIN, "ident connection to %s timed out",
2588 sender_host_address);
2589 }
2590 else
2591 {
2592 DEBUG(D_ident) debug_printf("ident connection to %s failed: %s\n",
2593 sender_host_address, strerror(errno));
2594 }
2595 goto END_OFF;
2596 }
2597
2598 /* Construct and send the query. */
2599
2600 sprintf(CS buffer, "%d , %d\r\n", sender_host_port, interface_port);
2601 qlen = Ustrlen(buffer);
2602 if (send(sock, buffer, qlen, 0) < 0)
2603 {
2604 DEBUG(D_ident) debug_printf("ident send failed: %s\n", strerror(errno));
2605 goto END_OFF;
2606 }
2607
2608 /* Read a response line. We put it into the rest of the buffer, using several
2609 recv() calls if necessary. */
2610
2611 p = buffer + qlen;
2612
2613 for (;;)
2614 {
2615 uschar *pp;
2616 int count;
2617 int size = sizeof(buffer) - (p - buffer);
2618
2619 if (size <= 0) goto END_OFF; /* Buffer filled without seeing \n. */
2620 count = ip_recv(sock, p, size, rfc1413_query_timeout);
2621 if (count <= 0) goto END_OFF; /* Read error or EOF */
2622
2623 /* Scan what we just read, to see if we have reached the terminating \r\n. Be
2624 generous, and accept a plain \n terminator as well. The only illegal
2625 character is 0. */
2626
2627 for (pp = p; pp < p + count; pp++)
2628 {
2629 if (*pp == 0) goto END_OFF; /* Zero octet not allowed */
2630 if (*pp == '\n')
2631 {
2632 if (pp[-1] == '\r') pp--;
2633 *pp = 0;
2634 goto GOT_DATA; /* Break out of both loops */
2635 }
2636 }
2637
2638 /* Reached the end of the data without finding \n. Let the loop continue to
2639 read some more, if there is room. */
2640
2641 p = pp;
2642 }
2643
2644 GOT_DATA:
2645
2646 /* We have received a line of data. Check it carefully. It must start with the
2647 same two port numbers that we sent, followed by data as defined by the RFC. For
2648 example,
2649
2650 12345 , 25 : USERID : UNIX :root
2651
2652 However, the amount of white space may be different to what we sent. In the
2653 "osname" field there may be several sub-fields, comma separated. The data we
2654 actually want to save follows the third colon. Some systems put leading spaces
2655 in it - we discard those. */
2656
2657 if (sscanf(CS buffer + qlen, "%d , %d%n", &received_sender_port,
2658 &received_interface_port, &n) != 2 ||
2659 received_sender_port != sender_host_port ||
2660 received_interface_port != interface_port)
2661 goto END_OFF;
2662
2663 p = buffer + qlen + n;
2664 while(isspace(*p)) p++;
2665 if (*p++ != ':') goto END_OFF;
2666 while(isspace(*p)) p++;
2667 if (Ustrncmp(p, "USERID", 6) != 0) goto END_OFF;
2668 p += 6;
2669 while(isspace(*p)) p++;
2670 if (*p++ != ':') goto END_OFF;
2671 while (*p != 0 && *p != ':') p++;
2672 if (*p++ == 0) goto END_OFF;
2673 while(isspace(*p)) p++;
2674 if (*p == 0) goto END_OFF;
2675
2676 /* The rest of the line is the data we want. We turn it into printing
2677 characters when we save it, so that it cannot mess up the format of any logging
2678 or Received: lines into which it gets inserted. We keep a maximum of 127
2679 characters. */
2680
2681 sender_ident = string_printing(string_copyn(p, 127));
2682 DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident);
2683
2684 END_OFF:
2685 (void)close(sock);
2686 return;
2687 }
2688
2689
2690
2691
2692 /*************************************************
2693 * Match host to a single host-list item *
2694 *************************************************/
2695
2696 /* This function compares a host (name or address) against a single item
2697 from a host list. The host name gets looked up if it is needed and is not
2698 already known. The function is called from verify_check_this_host() via
2699 match_check_list(), which is why most of its arguments are in a single block.
2700
2701 Arguments:
2702 arg the argument block (see below)
2703 ss the host-list item
2704 valueptr where to pass back looked up data, or NULL
2705 error for error message when returning ERROR
2706
2707 The block contains:
2708 host_name (a) the host name, or
2709 (b) NULL, implying use sender_host_name and
2710 sender_host_aliases, looking them up if required, or
2711 (c) the empty string, meaning that only IP address matches
2712 are permitted
2713 host_address the host address
2714 host_ipv4 the IPv4 address taken from an IPv6 one
2715
2716 Returns: OK matched
2717 FAIL did not match
2718 DEFER lookup deferred
2719 ERROR (a) failed to find the host name or IP address, or
2720 (b) unknown lookup type specified, or
2721 (c) host name encountered when only IP addresses are
2722 being matched
2723 */
2724
2725 int
2726 check_host(void *arg, uschar *ss, uschar **valueptr, uschar **error)
2727 {
2728 check_host_block *cb = (check_host_block *)arg;
2729 int mlen = -1;
2730 int maskoffset;
2731 BOOL iplookup = FALSE;
2732 BOOL isquery = FALSE;
2733 BOOL isiponly = cb->host_name != NULL && cb->host_name[0] == 0;
2734 uschar *t;
2735 uschar *semicolon;
2736 uschar **aliases;
2737
2738 /* Optimize for the special case when the pattern is "*". */
2739
2740 if (*ss == '*' && ss[1] == 0) return OK;
2741
2742 /* If the pattern is empty, it matches only in the case when there is no host -
2743 this can occur in ACL checking for SMTP input using the -bs option. In this
2744 situation, the host address is the empty string. */
2745
2746 if (cb->host_address[0] == 0) return (*ss == 0)? OK : FAIL;
2747 if (*ss == 0) return FAIL;
2748
2749 /* If the pattern is precisely "@" then match against the primary host name,
2750 provided that host name matching is permitted; if it's "@[]" match against the
2751 local host's IP addresses. */
2752
2753 if (*ss == '@')
2754 {
2755 if (ss[1] == 0)
2756 {
2757 if (isiponly) return ERROR;
2758 ss = primary_hostname;
2759 }
2760 else if (Ustrcmp(ss, "@[]") == 0)
2761 {
2762 ip_address_item *ip;
2763 for (ip = host_find_interfaces(); ip != NULL; ip = ip->next)
2764 if (Ustrcmp(ip->address, cb->host_address) == 0) return OK;
2765 return FAIL;
2766 }
2767 }
2768
2769 /* If the pattern is an IP address, optionally followed by a bitmask count, do
2770 a (possibly masked) comparision with the current IP address. */
2771
2772 if (string_is_ip_address(ss, &maskoffset) != 0)
2773 return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL);
2774
2775 /* The pattern is not an IP address. A common error that people make is to omit
2776 one component of an IPv4 address, either by accident, or believing that, for
2777 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,
2778 which it isn't. (Those applications that do accept 1.2.3 as an IP address
2779 interpret it as 1.2.0.3 because the final component becomes 16-bit - this is an
2780 ancient specification.) To aid in debugging these cases, we give a specific
2781 error if the pattern contains only digits and dots or contains a slash preceded
2782 only by digits and dots (a slash at the start indicates a file name and of
2783 course slashes may be present in lookups, but not preceded only by digits and
2784 dots). */
2785
2786 for (t = ss; isdigit(*t) || *t == '.'; t++);
2787 if (*t == 0 || (*t == '/' && t != ss))
2788 {
2789 *error = US"malformed IPv4 address or address mask";
2790 return ERROR;
2791 }
2792
2793 /* See if there is a semicolon in the pattern */
2794
2795 semicolon = Ustrchr(ss, ';');
2796
2797 /* If we are doing an IP address only match, then all lookups must be IP
2798 address lookups, even if there is no "net-". */
2799
2800 if (isiponly)
2801 {
2802 iplookup = semicolon != NULL;
2803 }
2804
2805 /* Otherwise, if the item is of the form net[n]-lookup;<file|query> then it is
2806 a lookup on a masked IP network, in textual form. We obey this code even if we
2807 have already set iplookup, so as to skip over the "net-" prefix and to set the
2808 mask length. The net- stuff really only applies to single-key lookups where the
2809 key is implicit. For query-style lookups the key is specified in the query.
2810 From release 4.30, the use of net- for query style is no longer needed, but we
2811 retain it for backward compatibility. */
2812
2813 if (Ustrncmp(ss, "net", 3) == 0 && semicolon != NULL)
2814 {
2815 mlen = 0;
2816 for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0';
2817 if (mlen == 0 && t == ss+3) mlen = -1; /* No mask supplied */
2818 iplookup = (*t++ == '-');
2819 }
2820 else t = ss;
2821
2822 /* Do the IP address lookup if that is indeed what we have */
2823
2824 if (iplookup)
2825 {
2826 int insize;
2827 int search_type;
2828 int incoming[4];
2829 void *handle;
2830 uschar *filename, *key, *result;
2831 uschar buffer[64];
2832
2833 /* Find the search type */
2834
2835 search_type = search_findtype(t, semicolon - t);
2836
2837 if (search_type < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
2838 search_error_message);
2839
2840 /* Adjust parameters for the type of lookup. For a query-style lookup, there
2841 is no file name, and the "key" is just the query. For query-style with a file
2842 name, we have to fish the file off the start of the query. For a single-key
2843 lookup, the key is the current IP address, masked appropriately, and
2844 reconverted to text form, with the mask appended. For IPv6 addresses, specify
2845 dot separators instead of colons, except when the lookup type is "iplsearch".
2846 */
2847
2848 if (mac_islookup(search_type, lookup_absfilequery))
2849 {
2850 filename = semicolon + 1;
2851 key = filename;
2852 while (*key != 0 && !isspace(*key)) key++;
2853 filename = string_copyn(filename, key - filename);
2854 while (isspace(*key)) key++;
2855 }
2856 else if (mac_islookup(search_type, lookup_querystyle))
2857 {
2858 filename = NULL;
2859 key = semicolon + 1;
2860 }
2861 else /* Single-key style */
2862 {
2863 int sep = (Ustrcmp(lookup_list[search_type]->name, "iplsearch") == 0)?
2864 ':' : '.';
2865 insize = host_aton(cb->host_address, incoming);
2866 host_mask(insize, incoming, mlen);
2867 (void)host_nmtoa(insize, incoming, mlen, buffer, sep);
2868 key = buffer;
2869 filename = semicolon + 1;
2870 }
2871
2872 /* Now do the actual lookup; note that there is no search_close() because
2873 of the caching arrangements. */
2874
2875 handle = search_open(filename, search_type, 0, NULL, NULL);
2876 if (handle == NULL) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
2877 search_error_message);
2878 result = search_find(handle, filename, key, -1, NULL, 0, 0, NULL);
2879 if (valueptr != NULL) *valueptr = result;
2880 return (result != NULL)? OK : search_find_defer? DEFER: FAIL;
2881 }
2882
2883 /* The pattern is not an IP address or network reference of any kind. That is,
2884 it is a host name pattern. If this is an IP only match, there's an error in the
2885 host list. */
2886
2887 if (isiponly)
2888 {
2889 *error = US"cannot match host name in match_ip list";
2890 return ERROR;
2891 }
2892
2893 /* Check the characters of the pattern to see if they comprise only letters,
2894 digits, full stops, and hyphens (the constituents of domain names). Allow
2895 underscores, as they are all too commonly found. Sigh. Also, if
2896 allow_utf8_domains is set, allow top-bit characters. */
2897
2898 for (t = ss; *t != 0; t++)
2899 if (!isalnum(*t) && *t != '.' && *t != '-' && *t != '_' &&
2900 (!allow_utf8_domains || *t < 128)) break;
2901
2902 /* If the pattern is a complete domain name, with no fancy characters, look up
2903 its IP address and match against that. Note that a multi-homed host will add
2904 items to the chain. */
2905
2906 if (*t == 0)
2907 {
2908 int rc;
2909 host_item h;
2910 h.next = NULL;
2911 h.name = ss;
2912 h.address = NULL;
2913 h.mx = MX_NONE;
2914
2915 rc = host_find_byname(&h, NULL, HOST_FIND_QUALIFY_SINGLE, NULL, FALSE);
2916 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2917 {
2918 host_item *hh;
2919 for (hh = &h; hh != NULL; hh = hh->next)
2920 {
2921 if (host_is_in_net(hh->address, cb->host_address, 0)) return OK;
2922 }
2923 return FAIL;
2924 }
2925 if (rc == HOST_FIND_AGAIN) return DEFER;
2926 *error = string_sprintf("failed to find IP address for %s", ss);
2927 return ERROR;
2928 }
2929
2930 /* Almost all subsequent comparisons require the host name, and can be done
2931 using the general string matching function. When this function is called for
2932 outgoing hosts, the name is always given explicitly. If it is NULL, it means we
2933 must use sender_host_name and its aliases, looking them up if necessary. */
2934
2935 if (cb->host_name != NULL) /* Explicit host name given */
2936 return match_check_string(cb->host_name, ss, -1, TRUE, TRUE, TRUE,
2937 valueptr);
2938
2939 /* Host name not given; in principle we need the sender host name and its
2940 aliases. However, for query-style lookups, we do not need the name if the
2941 query does not contain $sender_host_name. From release 4.23, a reference to
2942 $sender_host_name causes it to be looked up, so we don't need to do the lookup
2943 on spec. */
2944
2945 if ((semicolon = Ustrchr(ss, ';')) != NULL)
2946 {
2947 uschar *affix;
2948 int partial, affixlen, starflags, id;
2949
2950 *semicolon = 0;
2951 id = search_findtype_partial(ss, &partial, &affix, &affixlen, &starflags);
2952 *semicolon=';';
2953
2954 if (id < 0) /* Unknown lookup type */
2955 {
2956 log_write(0, LOG_MAIN|LOG_PANIC, "%s in host list item \"%s\"",
2957 search_error_message, ss);
2958 return DEFER;
2959 }
2960 isquery = mac_islookup(id, lookup_querystyle|lookup_absfilequery);
2961 }
2962
2963 if (isquery)
2964 {
2965 switch(match_check_string(US"", ss, -1, TRUE, TRUE, TRUE, valueptr))
2966 {
2967 case OK: return OK;
2968 case DEFER: return DEFER;
2969 default: return FAIL;
2970 }
2971 }
2972
2973 /* Not a query-style lookup; must ensure the host name is present, and then we
2974 do a check on the name and all its aliases. */
2975
2976 if (sender_host_name == NULL)
2977 {
2978 HDEBUG(D_host_lookup)
2979 debug_printf("sender host name required, to match against %s\n", ss);
2980 if (host_lookup_failed || host_name_lookup() != OK)
2981 {
2982 *error = string_sprintf("failed to find host name for %s",
2983 sender_host_address);;
2984 return ERROR;
2985 }
2986 host_build_sender_fullhost();
2987 }
2988
2989 /* Match on the sender host name, using the general matching function */
2990
2991 switch(match_check_string(sender_host_name, ss, -1, TRUE, TRUE, TRUE,
2992 valueptr))
2993 {
2994 case OK: return OK;
2995 case DEFER: return DEFER;
2996 }
2997
2998 /* If there are aliases, try matching on them. */
2999
3000 aliases = sender_host_aliases;
3001 while (*aliases != NULL)
3002 {
3003 switch(match_check_string(*aliases++, ss, -1, TRUE, TRUE, TRUE, valueptr))
3004 {
3005 case OK: return OK;
3006 case DEFER: return DEFER;
3007 }
3008 }
3009 return FAIL;
3010 }
3011
3012
3013
3014
3015 /*************************************************
3016 * Check a specific host matches a host list *
3017 *************************************************/
3018
3019 /* This function is passed a host list containing items in a number of
3020 different formats and the identity of a host. Its job is to determine whether
3021 the given host is in the set of hosts defined by the list. The host name is
3022 passed as a pointer so that it can be looked up if needed and not already
3023 known. This is commonly the case when called from verify_check_host() to check
3024 an incoming connection. When called from elsewhere the host name should usually
3025 be set.
3026
3027 This function is now just a front end to match_check_list(), which runs common
3028 code for scanning a list. We pass it the check_host() function to perform a
3029 single test.
3030
3031 Arguments:
3032 listptr pointer to the host list
3033 cache_bits pointer to cache for named lists, or NULL
3034 host_name the host name or NULL, implying use sender_host_name and
3035 sender_host_aliases, looking them up if required
3036 host_address the IP address
3037 valueptr if not NULL, data from a lookup is passed back here
3038
3039 Returns: OK if the host is in the defined set
3040 FAIL if the host is not in the defined set,
3041 DEFER if a data lookup deferred (not a host lookup)
3042
3043 If the host name was needed in order to make a comparison, and could not be
3044 determined from the IP address, the result is FAIL unless the item
3045 "+allow_unknown" was met earlier in the list, in which case OK is returned. */
3046
3047 int
3048 verify_check_this_host(uschar **listptr, unsigned int *cache_bits,
3049 uschar *host_name, uschar *host_address, uschar **valueptr)
3050 {
3051 int rc;
3052 unsigned int *local_cache_bits = cache_bits;
3053 uschar *save_host_address = deliver_host_address;
3054 check_host_block cb;
3055 cb.host_name = host_name;
3056 cb.host_address = host_address;
3057
3058 if (valueptr != NULL) *valueptr = NULL;
3059
3060 /* If the host address starts off ::ffff: it is an IPv6 address in
3061 IPv4-compatible mode. Find the IPv4 part for checking against IPv4
3062 addresses. */
3063
3064 cb.host_ipv4 = (Ustrncmp(host_address, "::ffff:", 7) == 0)?
3065 host_address + 7 : host_address;
3066
3067 /* During the running of the check, put the IP address into $host_address. In
3068 the case of calls from the smtp transport, it will already be there. However,
3069 in other calls (e.g. when testing ignore_target_hosts), it won't. Just to be on
3070 the safe side, any existing setting is preserved, though as I write this
3071 (November 2004) I can't see any cases where it is actually needed. */
3072
3073 deliver_host_address = host_address;
3074 rc = match_check_list(
3075 listptr, /* the list */
3076 0, /* separator character */
3077 &hostlist_anchor, /* anchor pointer */
3078 &local_cache_bits, /* cache pointer */
3079 check_host, /* function for testing */
3080 &cb, /* argument for function */
3081 MCL_HOST, /* type of check */
3082 (host_address == sender_host_address)?
3083 US"host" : host_address, /* text for debugging */
3084 valueptr); /* where to pass back data */
3085 deliver_host_address = save_host_address;
3086 return rc;
3087 }
3088
3089
3090
3091
3092 /*************************************************
3093 * Check the remote host matches a list *
3094 *************************************************/
3095
3096 /* This is a front end to verify_check_this_host(), created because checking
3097 the remote host is a common occurrence. With luck, a good compiler will spot
3098 the tail recursion and optimize it. If there's no host address, this is
3099 command-line SMTP input - check against an empty string for the address.
3100
3101 Arguments:
3102 listptr pointer to the host list
3103
3104 Returns: the yield of verify_check_this_host(),
3105 i.e. OK, FAIL, or DEFER
3106 */
3107
3108 int
3109 verify_check_host(uschar **listptr)
3110 {
3111 return verify_check_this_host(listptr, sender_host_cache, NULL,
3112 (sender_host_address == NULL)? US"" : sender_host_address, NULL);
3113 }
3114
3115
3116
3117
3118
3119 /*************************************************
3120 * Invert an IP address *
3121 *************************************************/
3122
3123 /* Originally just used for DNS xBL lists, now also used for the
3124 reverse_ip expansion operator.
3125
3126 Arguments:
3127 buffer where to put the answer
3128 address the address to invert
3129 */
3130
3131 void
3132 invert_address(uschar *buffer, uschar *address)
3133 {
3134 int bin[4];
3135 uschar *bptr = buffer;
3136
3137 /* If this is an IPv4 address mapped into IPv6 format, adjust the pointer
3138 to the IPv4 part only. */
3139
3140 if (Ustrncmp(address, "::ffff:", 7) == 0) address += 7;
3141
3142 /* Handle IPv4 address: when HAVE_IPV6 is false, the result of host_aton() is
3143 always 1. */
3144
3145 if (host_aton(address, bin) == 1)
3146 {
3147 int i;
3148 int x = bin[0];
3149 for (i = 0; i < 4; i++)
3150 {
3151 sprintf(CS bptr, "%d.", x & 255);
3152 while (*bptr) bptr++;
3153 x >>= 8;
3154 }
3155 }
3156
3157 /* Handle IPv6 address. Actually, as far as I know, there are no IPv6 addresses
3158 in any DNS black lists, and the format in which they will be looked up is
3159 unknown. This is just a guess. */
3160
3161 #if HAVE_IPV6
3162 else
3163 {
3164 int i, j;
3165 for (j = 3; j >= 0; j--)
3166 {
3167 int x = bin[j];
3168 for (i = 0; i < 8; i++)
3169 {
3170 sprintf(CS bptr, "%x.", x & 15);
3171 while (*bptr) bptr++;
3172 x >>= 4;
3173 }
3174 }
3175 }
3176 #endif
3177
3178 /* Remove trailing period -- this is needed so that both arbitrary
3179 dnsbl keydomains and inverted addresses may be combined with the
3180 same format string, "%s.%s" */
3181
3182 *(--bptr) = 0;
3183 }
3184
3185
3186
3187 /*************************************************
3188 * Perform a single dnsbl lookup *
3189 *************************************************/
3190
3191 /* This function is called from verify_check_dnsbl() below. It is also called
3192 recursively from within itself when domain and domain_txt are different
3193 pointers, in order to get the TXT record from the alternate domain.
3194
3195 Arguments:
3196 domain the outer dnsbl domain
3197 domain_txt alternate domain to lookup TXT record on success; when the
3198 same domain is to be used, domain_txt == domain (that is,
3199 the pointers must be identical, not just the text)
3200 keydomain the current keydomain (for debug message)
3201 prepend subdomain to lookup (like keydomain, but
3202 reversed if IP address)
3203 iplist the list of matching IP addresses, or NULL for "any"
3204 bitmask true if bitmask matching is wanted
3205 match_type condition for 'succeed' result
3206 0 => Any RR in iplist (=)
3207 1 => No RR in iplist (!=)
3208 2 => All RRs in iplist (==)
3209 3 => Some RRs not in iplist (!==)
3210 the two bits are defined as MT_NOT and MT_ALL
3211 defer_return what to return for a defer
3212
3213 Returns: OK if lookup succeeded
3214 FAIL if not
3215 */
3216
3217 static int
3218 one_check_dnsbl(uschar *domain, uschar *domain_txt, uschar *keydomain,
3219 uschar *prepend, uschar *iplist, BOOL bitmask, int match_type,
3220 int defer_return)
3221 {
3222 dns_answer dnsa;
3223 dns_scan dnss;
3224 tree_node *t;
3225 dnsbl_cache_block *cb;
3226 int old_pool = store_pool;
3227 uschar query[256]; /* DNS domain max length */
3228
3229 /* Construct the specific query domainname */
3230
3231 if (!string_format(query, sizeof(query), "%s.%s", prepend, domain))
3232 {
3233 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
3234 "(ignored): %s...", query);
3235 return FAIL;
3236 }
3237
3238 /* Look for this query in the cache. */
3239
3240 t = tree_search(dnsbl_cache, query);
3241
3242 /* If not cached from a previous lookup, we must do a DNS lookup, and
3243 cache the result in permanent memory. */
3244
3245 if (t == NULL)
3246 {
3247 store_pool = POOL_PERM;
3248
3249 /* Set up a tree entry to cache the lookup */
3250
3251 t = store_get(sizeof(tree_node) + Ustrlen(query));
3252 Ustrcpy(t->name, query);
3253 t->data.ptr = cb = store_get(sizeof(dnsbl_cache_block));
3254 (void)tree_insertnode(&dnsbl_cache, t);
3255
3256 /* Do the DNS loopup . */
3257
3258 HDEBUG(D_dnsbl) debug_printf("new DNS lookup for %s\n", query);
3259 cb->rc = dns_basic_lookup(&dnsa, query, T_A);
3260 cb->text_set = FALSE;
3261 cb->text = NULL;
3262 cb->rhs = NULL;
3263
3264 /* If the lookup succeeded, cache the RHS address. The code allows for
3265 more than one address - this was for complete generality and the possible
3266 use of A6 records. However, A6 records have been reduced to experimental
3267 status (August 2001) and may die out. So they may never get used at all,
3268 let alone in dnsbl records. However, leave the code here, just in case.
3269
3270 Quite apart from one A6 RR generating multiple addresses, there are DNS
3271 lists that return more than one A record, so we must handle multiple
3272 addresses generated in that way as well. */
3273
3274 if (cb->rc == DNS_SUCCEED)
3275 {
3276 dns_record *rr;
3277 dns_address **addrp = &(cb->rhs);
3278 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
3279 rr != NULL;
3280 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3281 {
3282 if (rr->type == T_A)
3283 {
3284 dns_address *da = dns_address_from_rr(&dnsa, rr);
3285 if (da != NULL)
3286 {
3287 *addrp = da;
3288 while (da->next != NULL) da = da->next;
3289 addrp = &(da->next);
3290 }
3291 }
3292 }
3293
3294 /* If we didn't find any A records, change the return code. This can
3295 happen when there is a CNAME record but there are no A records for what
3296 it points to. */
3297
3298 if (cb->rhs == NULL) cb->rc = DNS_NODATA;
3299 }
3300
3301 store_pool = old_pool;
3302 }
3303
3304 /* Previous lookup was cached */
3305
3306 else
3307 {
3308 HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
3309 cb = t->data.ptr;
3310 }
3311
3312 /* We now have the result of the DNS lookup, either newly done, or cached
3313 from a previous call. If the lookup succeeded, check against the address
3314 list if there is one. This may be a positive equality list (introduced by
3315 "="), a negative equality list (introduced by "!="), a positive bitmask
3316 list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/
3317
3318 if (cb->rc == DNS_SUCCEED)
3319 {
3320 dns_address *da = NULL;
3321 uschar *addlist = cb->rhs->address;
3322
3323 /* For A and AAAA records, there may be multiple addresses from multiple
3324 records. For A6 records (currently not expected to be used) there may be
3325 multiple addresses from a single record. */
3326
3327 for (da = cb->rhs->next; da != NULL; da = da->next)
3328 addlist = string_sprintf("%s, %s", addlist, da->address);
3329
3330 HDEBUG(D_dnsbl) debug_printf("DNS lookup for %s succeeded (yielding %s)\n",
3331 query, addlist);
3332
3333 /* Address list check; this can be either for equality, or via a bitmask.
3334 In the latter case, all the bits must match. */
3335
3336 if (iplist != NULL)
3337 {
3338 for (da = cb->rhs; da != NULL; da = da->next)
3339 {
3340 int ipsep = ',';
3341 uschar ip[46];
3342 uschar *ptr = iplist;
3343 uschar *res;
3344
3345 /* Handle exact matching */
3346
3347 if (!bitmask)
3348 {
3349 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))) != NULL)
3350 {
3351 if (Ustrcmp(CS da->address, ip) == 0) break;
3352 }
3353 }
3354
3355 /* Handle bitmask matching */
3356
3357 else
3358 {
3359 int address[4];
3360 int mask = 0;
3361
3362 /* At present, all known DNS blocking lists use A records, with
3363 IPv4 addresses on the RHS encoding the information they return. I
3364 wonder if this will linger on as the last vestige of IPv4 when IPv6
3365 is ubiquitous? Anyway, for now we use paranoia code to completely
3366 ignore IPv6 addresses. The default mask is 0, which always matches.
3367 We change this only for IPv4 addresses in the list. */
3368
3369 if (host_aton(da->address, address) == 1) mask = address[0];
3370
3371 /* Scan the returned addresses, skipping any that are IPv6 */
3372
3373 while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip))) != NULL)
3374 {
3375 if (host_aton(ip, address) != 1) continue;
3376 if ((address[0] & mask) == address[0]) break;
3377 }
3378 }
3379
3380 /* If either
3381
3382 (a) An IP address in an any ('=') list matched, or
3383 (b) No IP address in an all ('==') list matched
3384
3385 then we're done searching. */
3386
3387 if (((match_type & MT_ALL) != 0) == (res == NULL)) break;
3388 }
3389
3390 /* If da == NULL, either
3391
3392 (a) No IP address in an any ('=') list matched, or
3393 (b) An IP address in an all ('==') list didn't match
3394
3395 so behave as if the DNSBL lookup had not succeeded, i.e. the host is not on
3396 the list. */
3397
3398 if ((match_type == MT_NOT || match_type == MT_ALL) != (da == NULL))
3399 {
3400 HDEBUG(D_dnsbl)
3401 {
3402 uschar *res = NULL;
3403 switch(match_type)
3404 {
3405 case 0:
3406 res = US"was no match";
3407 break;
3408 case MT_NOT:
3409 res = US"was an exclude match";
3410 break;
3411 case MT_ALL:
3412 res = US"was an IP address that did not match";
3413 break;
3414 case MT_NOT|MT_ALL:
3415 res = US"were no IP addresses that did not match";
3416 break;
3417 }
3418 debug_printf("=> but we are not accepting this block class because\n");
3419 debug_printf("=> there %s for %s%c%s\n",
3420 res,
3421 ((match_type & MT_ALL) == 0)? "" : "=",
3422 bitmask? '&' : '=', iplist);
3423 }
3424 return FAIL;
3425 }
3426 }
3427
3428 /* Either there was no IP list, or the record matched, implying that the
3429 domain is on the list. We now want to find a corresponding TXT record. If an
3430 alternate domain is specified for the TXT record, call this function
3431 recursively to look that up; this has the side effect of re-checking that
3432 there is indeed an A record at the alternate domain. */
3433
3434 if (domain_txt != domain)
3435 return one_check_dnsbl(domain_txt, domain_txt, keydomain, prepend, NULL,
3436 FALSE, match_type, defer_return);
3437
3438 /* If there is no alternate domain, look up a TXT record in the main domain
3439 if it has not previously been cached. */
3440
3441 if (!cb->text_set)
3442 {
3443 cb->text_set = TRUE;
3444 if (dns_basic_lookup(&dnsa, query, T_TXT) == DNS_SUCCEED)
3445 {
3446 dns_record *rr;
3447 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
3448 rr != NULL;
3449 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
3450 if (rr->type == T_TXT) break;
3451 if (rr != NULL)
3452 {
3453 int len = (rr->data)[0];
3454 if (len > 511) len = 127;
3455 st