4.52 TK/01
[exim.git] / src / src / verify.c
CommitLineData
384152a6 1/* $Cambridge: exim/src/src/verify.c,v 1.17 2005/05/24 08:15:02 tom Exp $ */
059ec3d9
PH
2
3/*************************************************
4* Exim - an Internet mail transport agent *
5*************************************************/
6
c988f1f4 7/* Copyright (c) University of Cambridge 1995 - 2005 */
059ec3d9
PH
8/* See the file NOTICE for conditions of use and distribution. */
9
10/* Functions concerned with verifying things. The original code for callout
11caching was contributed by Kevin Fleming (but I hacked it around a bit). */
12
13
14#include "exim.h"
15
16
17/* Structure for caching DNSBL lookups */
18
19typedef struct dnsbl_cache_block {
20 dns_address *rhs;
21 uschar *text;
22 int rc;
23 BOOL text_set;
24} dnsbl_cache_block;
25
26
27/* Anchor for DNSBL cache */
28
29static tree_node *dnsbl_cache = NULL;
30
31
32
33/*************************************************
34* Retrieve a callout cache record *
35*************************************************/
36
37/* If a record exists, check whether it has expired.
38
39Arguments:
40 dbm_file an open hints file
41 key the record key
42 type "address" or "domain"
43 positive_expire expire time for positive records
44 negative_expire expire time for negative records
45
46Returns: the cache record if a non-expired one exists, else NULL
47*/
48
49static dbdata_callout_cache *
50get_callout_cache_record(open_db *dbm_file, uschar *key, uschar *type,
51 int positive_expire, int negative_expire)
52{
53BOOL negative;
54int length, expire;
55time_t now;
56dbdata_callout_cache *cache_record;
57
58cache_record = dbfn_read_with_length(dbm_file, key, &length);
59
60if (cache_record == NULL)
61 {
62 HDEBUG(D_verify) debug_printf("callout cache: no %s record found\n", type);
63 return NULL;
64 }
65
66/* We treat a record as "negative" if its result field is not positive, or if
67it is a domain record and the postmaster field is negative. */
68
69negative = cache_record->result != ccache_accept ||
70 (type[0] == 'd' && cache_record->postmaster_result == ccache_reject);
71expire = negative? negative_expire : positive_expire;
72now = time(NULL);
73
74if (now - cache_record->time_stamp > expire)
75 {
76 HDEBUG(D_verify) debug_printf("callout cache: %s record expired\n", type);
77 return NULL;
78 }
79
80/* If this is a non-reject domain record, check for the obsolete format version
81that doesn't have the postmaster and random timestamps, by looking at the
82length. If so, copy it to a new-style block, replicating the record's
83timestamp. Then check the additional timestamps. (There's no point wasting
84effort if connections are rejected.) */
85
86if (type[0] == 'd' && cache_record->result != ccache_reject)
87 {
88 if (length == sizeof(dbdata_callout_cache_obs))
89 {
90 dbdata_callout_cache *new = store_get(sizeof(dbdata_callout_cache));
91 memcpy(new, cache_record, length);
92 new->postmaster_stamp = new->random_stamp = new->time_stamp;
93 cache_record = new;
94 }
95
96 if (now - cache_record->postmaster_stamp > expire)
97 cache_record->postmaster_result = ccache_unknown;
98
99 if (now - cache_record->random_stamp > expire)
100 cache_record->random_result = ccache_unknown;
101 }
102
103HDEBUG(D_verify) debug_printf("callout cache: found %s record\n", type);
104return cache_record;
105}
106
107
108
109/*************************************************
110* Do callout verification for an address *
111*************************************************/
112
113/* This function is called from verify_address() when the address has routed to
114a host list, and a callout has been requested. Callouts are expensive; that is
115why a cache is used to improve the efficiency.
116
117Arguments:
118 addr the address that's been routed
119 host_list the list of hosts to try
120 tf the transport feedback block
121
122 ifstring "interface" option from transport, or NULL
123 portstring "port" option from transport, or NULL
124 protocolstring "protocol" option from transport, or NULL
125 callout the per-command callout timeout
4deaf07d
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126 callout_overall the overall callout timeout (if < 0 use 4*callout)
127 callout_connect the callout connection timeout (if < 0 use callout)
059ec3d9
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128 options the verification options - these bits are used:
129 vopt_is_recipient => this is a recipient address
130 vopt_callout_no_cache => don't use callout cache
131 vopt_callout_random => do the "random" thing
132 vopt_callout_recipsender => use real sender for recipient
133 vopt_callout_recippmaster => use postmaster for recipient
134 se_mailfrom MAIL FROM address for sender verify; NULL => ""
135 pm_mailfrom if non-NULL, do the postmaster check with this sender
136
137Returns: OK/FAIL/DEFER
138*/
139
140static int
141do_callout(address_item *addr, host_item *host_list, transport_feedback *tf,
8e669ac1 142 int callout, int callout_overall, int callout_connect, int options,
4deaf07d 143 uschar *se_mailfrom, uschar *pm_mailfrom)
059ec3d9
PH
144{
145BOOL is_recipient = (options & vopt_is_recipient) != 0;
146BOOL callout_no_cache = (options & vopt_callout_no_cache) != 0;
147BOOL callout_random = (options & vopt_callout_random) != 0;
148
149int yield = OK;
150BOOL done = FALSE;
151uschar *address_key;
152uschar *from_address;
153uschar *random_local_part = NULL;
8e669ac1 154uschar **failure_ptr = is_recipient?
2c7db3f5 155 &recipient_verify_failure : &sender_verify_failure;
059ec3d9
PH
156open_db dbblock;
157open_db *dbm_file = NULL;
158dbdata_callout_cache new_domain_record;
159dbdata_callout_cache_address new_address_record;
160host_item *host;
161time_t callout_start_time;
162
163new_domain_record.result = ccache_unknown;
164new_domain_record.postmaster_result = ccache_unknown;
165new_domain_record.random_result = ccache_unknown;
166
167memset(&new_address_record, 0, sizeof(new_address_record));
168
169/* For a recipient callout, the key used for the address cache record must
170include the sender address if we are using the real sender in the callout,
171because that may influence the result of the callout. */
172
173address_key = addr->address;
174from_address = US"";
175
176if (is_recipient)
177 {
178 if ((options & vopt_callout_recipsender) != 0)
179 {
180 address_key = string_sprintf("%s/<%s>", addr->address, sender_address);
181 from_address = sender_address;
182 }
183 else if ((options & vopt_callout_recippmaster) != 0)
184 {
185 address_key = string_sprintf("%s/<postmaster@%s>", addr->address,
186 qualify_domain_sender);
187 from_address = string_sprintf("postmaster@%s", qualify_domain_sender);
188 }
189 }
190
191/* For a sender callout, we must adjust the key if the mailfrom address is not
192empty. */
193
194else
195 {
196 from_address = (se_mailfrom == NULL)? US"" : se_mailfrom;
197 if (from_address[0] != 0)
198 address_key = string_sprintf("%s/<%s>", addr->address, from_address);
199 }
200
201/* Open the callout cache database, it it exists, for reading only at this
202stage, unless caching has been disabled. */
203
204if (callout_no_cache)
205 {
206 HDEBUG(D_verify) debug_printf("callout cache: disabled by no_cache\n");
207 }
208else if ((dbm_file = dbfn_open(US"callout", O_RDWR, &dbblock, FALSE)) == NULL)
209 {
210 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
211 }
212
213/* If a cache database is available see if we can avoid the need to do an
214actual callout by making use of previously-obtained data. */
215
216if (dbm_file != NULL)
217 {
218 dbdata_callout_cache_address *cache_address_record;
219 dbdata_callout_cache *cache_record = get_callout_cache_record(dbm_file,
220 addr->domain, US"domain",
221 callout_cache_domain_positive_expire,
222 callout_cache_domain_negative_expire);
223
224 /* If an unexpired cache record was found for this domain, see if the callout
225 process can be short-circuited. */
226
227 if (cache_record != NULL)
228 {
229 /* If an early command (up to and including MAIL FROM:<>) was rejected,
230 there is no point carrying on. The callout fails. */
231
232 if (cache_record->result == ccache_reject)
233 {
234 setflag(addr, af_verify_nsfail);
235 HDEBUG(D_verify)
236 debug_printf("callout cache: domain gave initial rejection, or "
237 "does not accept HELO or MAIL FROM:<>\n");
238 setflag(addr, af_verify_nsfail);
239 addr->user_message = US"(result of an earlier callout reused).";
240 yield = FAIL;
8e669ac1 241 *failure_ptr = US"mail";
059ec3d9
PH
242 goto END_CALLOUT;
243 }
244
245 /* If a previous check on a "random" local part was accepted, we assume
246 that the server does not do any checking on local parts. There is therefore
247 no point in doing the callout, because it will always be successful. If a
248 random check previously failed, arrange not to do it again, but preserve
249 the data in the new record. If a random check is required but hasn't been
250 done, skip the remaining cache processing. */
251
252 if (callout_random) switch(cache_record->random_result)
253 {
254 case ccache_accept:
255 HDEBUG(D_verify)
256 debug_printf("callout cache: domain accepts random addresses\n");
257 goto END_CALLOUT; /* Default yield is OK */
258
259 case ccache_reject:
260 HDEBUG(D_verify)
261 debug_printf("callout cache: domain rejects random addresses\n");
262 callout_random = FALSE;
263 new_domain_record.random_result = ccache_reject;
264 new_domain_record.random_stamp = cache_record->random_stamp;
265 break;
266
267 default:
268 HDEBUG(D_verify)
269 debug_printf("callout cache: need to check random address handling "
270 "(not cached or cache expired)\n");
271 goto END_CACHE;
272 }
273
274 /* If a postmaster check is requested, but there was a previous failure,
275 there is again no point in carrying on. If a postmaster check is required,
276 but has not been done before, we are going to have to do a callout, so skip
277 remaining cache processing. */
278
279 if (pm_mailfrom != NULL)
280 {
281 if (cache_record->postmaster_result == ccache_reject)
282 {
283 setflag(addr, af_verify_pmfail);
284 HDEBUG(D_verify)
285 debug_printf("callout cache: domain does not accept "
286 "RCPT TO:<postmaster@domain>\n");
287 yield = FAIL;
8e669ac1 288 *failure_ptr = US"postmaster";
059ec3d9
PH
289 setflag(addr, af_verify_pmfail);
290 addr->user_message = US"(result of earlier verification reused).";
291 goto END_CALLOUT;
292 }
293 if (cache_record->postmaster_result == ccache_unknown)
294 {
295 HDEBUG(D_verify)
296 debug_printf("callout cache: need to check RCPT "
297 "TO:<postmaster@domain> (not cached or cache expired)\n");
298 goto END_CACHE;
299 }
300
301 /* If cache says OK, set pm_mailfrom NULL to prevent a redundant
302 postmaster check if the address itself has to be checked. Also ensure
303 that the value in the cache record is preserved (with its old timestamp).
304 */
305
306 HDEBUG(D_verify) debug_printf("callout cache: domain accepts RCPT "
307 "TO:<postmaster@domain>\n");
308 pm_mailfrom = NULL;
309 new_domain_record.postmaster_result = ccache_accept;
310 new_domain_record.postmaster_stamp = cache_record->postmaster_stamp;
311 }
312 }
313
314 /* We can't give a result based on information about the domain. See if there
315 is an unexpired cache record for this specific address (combined with the
316 sender address if we are doing a recipient callout with a non-empty sender).
317 */
318
319 cache_address_record = (dbdata_callout_cache_address *)
320 get_callout_cache_record(dbm_file,
321 address_key, US"address",
322 callout_cache_positive_expire,
323 callout_cache_negative_expire);
324
325 if (cache_address_record != NULL)
326 {
327 if (cache_address_record->result == ccache_accept)
328 {
329 HDEBUG(D_verify)
330 debug_printf("callout cache: address record is positive\n");
331 }
332 else
333 {
334 HDEBUG(D_verify)
335 debug_printf("callout cache: address record is negative\n");
336 addr->user_message = US"Previous (cached) callout verification failure";
8e669ac1 337 *failure_ptr = US"recipient";
059ec3d9
PH
338 yield = FAIL;
339 }
340 goto END_CALLOUT;
341 }
342
343 /* Close the cache database while we actually do the callout for real. */
344
345 END_CACHE:
346 dbfn_close(dbm_file);
347 dbm_file = NULL;
348 }
349
350/* The information wasn't available in the cache, so we have to do a real
351callout and save the result in the cache for next time, unless no_cache is set,
352or unless we have a previously cached negative random result. If we are to test
353with a random local part, ensure that such a local part is available. If not,
354log the fact, but carry on without randomming. */
355
356if (callout_random && callout_random_local_part != NULL)
357 {
358 random_local_part = expand_string(callout_random_local_part);
359 if (random_local_part == NULL)
360 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand "
361 "callout_random_local_part: %s", expand_string_message);
362 }
363
4deaf07d
PH
364/* Default the connect and overall callout timeouts if not set, and record the
365time we are starting so that we can enforce it. */
059ec3d9
PH
366
367if (callout_overall < 0) callout_overall = 4 * callout;
4deaf07d 368if (callout_connect < 0) callout_connect = callout;
059ec3d9
PH
369callout_start_time = time(NULL);
370
371/* Now make connections to the hosts and do real callouts. The list of hosts
372is passed in as an argument. */
373
374for (host = host_list; host != NULL && !done; host = host->next)
375 {
376 smtp_inblock inblock;
377 smtp_outblock outblock;
378 int host_af;
379 int port = 25;
8e669ac1 380 BOOL send_quit = TRUE;
059ec3d9
PH
381 uschar *helo = US"HELO";
382 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
383 uschar inbuffer[4096];
384 uschar outbuffer[1024];
385 uschar responsebuffer[4096];
386
387 clearflag(addr, af_verify_pmfail); /* postmaster callout flag */
388 clearflag(addr, af_verify_nsfail); /* null sender callout flag */
389
390 /* Skip this host if we don't have an IP address for it. */
391
392 if (host->address == NULL)
393 {
394 DEBUG(D_verify) debug_printf("no IP address for host name %s: skipping\n",
395 host->name);
396 continue;
397 }
398
399 /* Check the overall callout timeout */
400
401 if (time(NULL) - callout_start_time >= callout_overall)
402 {
403 HDEBUG(D_verify) debug_printf("overall timeout for callout exceeded\n");
404 break;
405 }
406
407 /* Set IPv4 or IPv6 */
408
409 host_af = (Ustrchr(host->address, ':') == NULL)? AF_INET:AF_INET6;
410
411 /* Expand and interpret the interface and port strings. This has to
412 be delayed till now, because they may expand differently for different
413 hosts. If there's a failure, log it, but carry on with the defaults. */
414
415 deliver_host = host->name;
416 deliver_host_address = host->address;
417 if (!smtp_get_interface(tf->interface, host_af, addr, NULL, &interface,
418 US"callout") ||
419 !smtp_get_port(tf->port, addr, &port, US"callout"))
420 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
421 addr->message);
422 deliver_host = deliver_host_address = NULL;
423
424 /* Set HELO string according to the protocol */
425
426 if (Ustrcmp(tf->protocol, "lmtp") == 0) helo = US"LHLO";
427
428 HDEBUG(D_verify) debug_printf("interface=%s port=%d\n", interface, port);
429
430 /* Set up the buffer for reading SMTP response packets. */
431
432 inblock.buffer = inbuffer;
433 inblock.buffersize = sizeof(inbuffer);
434 inblock.ptr = inbuffer;
435 inblock.ptrend = inbuffer;
436
437 /* Set up the buffer for holding SMTP commands while pipelining */
438
439 outblock.buffer = outbuffer;
440 outblock.buffersize = sizeof(outbuffer);
441 outblock.ptr = outbuffer;
442 outblock.cmd_count = 0;
443 outblock.authenticating = FALSE;
444
445 /* Connect to the host; on failure, just loop for the next one, but we
4deaf07d 446 set the error for the last one. Use the callout_connect timeout. */
059ec3d9
PH
447
448 inblock.sock = outblock.sock =
4deaf07d 449 smtp_connect(host, host_af, port, interface, callout_connect, TRUE);
059ec3d9
PH
450 if (inblock.sock < 0)
451 {
452 addr->message = string_sprintf("could not connect to %s [%s]: %s",
453 host->name, host->address, strerror(errno));
454 continue;
455 }
456
457 /* Wait for initial response, and then run the initial SMTP commands. The
458 smtp_write_command() function leaves its command in big_buffer. This is
459 used in error responses. Initialize it in case the connection is
460 rejected. */
461
462 Ustrcpy(big_buffer, "initial connection");
463
464 done =
465 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
466 '2', callout) &&
467
468 smtp_write_command(&outblock, FALSE, "%s %s\r\n", helo,
469 smtp_active_hostname) >= 0 &&
470 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
471 '2', callout) &&
472
473 smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>\r\n",
474 from_address) >= 0 &&
475 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
476 '2', callout);
477
478 /* If the host gave an initial error, or does not accept HELO or MAIL
479 FROM:<>, arrange to cache this information, but don't record anything for an
480 I/O error or a defer. Do not cache rejections when a non-empty sender has
481 been used, because that blocks the whole domain for all senders. */
482
483 if (!done)
484 {
8e669ac1 485 *failure_ptr = US"mail";
059ec3d9
PH
486 if (errno == 0 && responsebuffer[0] == '5')
487 {
488 setflag(addr, af_verify_nsfail);
489 if (from_address[0] == 0) new_domain_record.result = ccache_reject;
490 }
491 }
492
493 /* Otherwise, proceed to check a "random" address (if required), then the
494 given address, and the postmaster address (if required). Between each check,
495 issue RSET, because some servers accept only one recipient after MAIL
496 FROM:<>. */
497
498 else
499 {
500 new_domain_record.result = ccache_accept;
501
502 /* Do the random local part check first */
503
504 if (random_local_part != NULL)
505 {
506 uschar randombuffer[1024];
507 BOOL random_ok =
508 smtp_write_command(&outblock, FALSE,
509 "RCPT TO:<%.1000s@%.1000s>\r\n", random_local_part,
510 addr->domain) >= 0 &&
511 smtp_read_response(&inblock, randombuffer,
512 sizeof(randombuffer), '2', callout);
513
514 /* Remember when we last did a random test */
515
516 new_domain_record.random_stamp = time(NULL);
517
518 /* If accepted, we aren't going to do any further tests below. */
519
520 if (random_ok)
521 {
522 new_domain_record.random_result = ccache_accept;
523 }
524
525 /* Otherwise, cache a real negative response, and get back to the right
526 state to send RCPT. Unless there's some problem such as a dropped
527 connection, we expect to succeed, because the commands succeeded above. */
528
529 else if (errno == 0)
530 {
531 if (randombuffer[0] == '5')
532 new_domain_record.random_result = ccache_reject;
533
534 done =
535 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
536 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
537 '2', callout) &&
538
539 smtp_write_command(&outblock, FALSE, "MAIL FROM:<>\r\n") >= 0 &&
540 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
541 '2', callout);
542 }
543 else done = FALSE; /* Some timeout/connection problem */
544 } /* Random check */
545
546 /* If the host is accepting all local parts, as determined by the "random"
547 check, we don't need to waste time doing any further checking. */
548
549 if (new_domain_record.random_result != ccache_accept && done)
550 {
551 done =
552 smtp_write_command(&outblock, FALSE, "RCPT TO:<%.1000s>\r\n",
c688b954
PH
553 transport_rcpt_address(addr,
554 addr->transport->rcpt_include_affixes)) >= 0 &&
059ec3d9
PH
555 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
556 '2', callout);
557
558 if (done)
559 new_address_record.result = ccache_accept;
560 else if (errno == 0 && responsebuffer[0] == '5')
2c7db3f5 561 {
8e669ac1 562 *failure_ptr = US"recipient";
059ec3d9 563 new_address_record.result = ccache_reject;
8e669ac1 564 }
059ec3d9
PH
565
566 /* Do postmaster check if requested */
567
568 if (done && pm_mailfrom != NULL)
569 {
570 done =
571 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
572 smtp_read_response(&inblock, responsebuffer,
573 sizeof(responsebuffer), '2', callout) &&
574
575 smtp_write_command(&outblock, FALSE,
576 "MAIL FROM:<%s>\r\n", pm_mailfrom) >= 0 &&
577 smtp_read_response(&inblock, responsebuffer,
578 sizeof(responsebuffer), '2', callout) &&
579
580 smtp_write_command(&outblock, FALSE,
581 "RCPT TO:<postmaster@%.1000s>\r\n", addr->domain) >= 0 &&
582 smtp_read_response(&inblock, responsebuffer,
583 sizeof(responsebuffer), '2', callout);
584
585 new_domain_record.postmaster_stamp = time(NULL);
586
587 if (done)
588 new_domain_record.postmaster_result = ccache_accept;
589 else if (errno == 0 && responsebuffer[0] == '5')
590 {
8e669ac1 591 *failure_ptr = US"postmaster";
059ec3d9
PH
592 setflag(addr, af_verify_pmfail);
593 new_domain_record.postmaster_result = ccache_reject;
594 }
595 }
596 } /* Random not accepted */
597 } /* MAIL FROM:<> accepted */
598
599 /* For any failure of the main check, other than a negative response, we just
600 close the connection and carry on. We can identify a negative response by the
601 fact that errno is zero. For I/O errors it will be non-zero
602
603 Set up different error texts for logging and for sending back to the caller
604 as an SMTP response. Log in all cases, using a one-line format. For sender
605 callouts, give a full response to the caller, but for recipient callouts,
606 don't give the IP address because this may be an internal host whose identity
607 is not to be widely broadcast. */
608
609 if (!done)
610 {
611 if (errno == ETIMEDOUT)
612 {
613 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
8e669ac1 614 send_quit = FALSE;
059ec3d9
PH
615 }
616 else if (errno == 0)
617 {
618 if (*responsebuffer == 0) Ustrcpy(responsebuffer, US"connection dropped");
619
620 addr->message =
621 string_sprintf("response to \"%s\" from %s [%s] was: %s",
622 big_buffer, host->name, host->address,
623 string_printing(responsebuffer));
624
625 addr->user_message = is_recipient?
626 string_sprintf("Callout verification failed:\n%s", responsebuffer)
627 :
628 string_sprintf("Called: %s\nSent: %s\nResponse: %s",
629 host->address, big_buffer, responsebuffer);
630
631 /* Hard rejection ends the process */
632
633 if (responsebuffer[0] == '5') /* Address rejected */
634 {
635 yield = FAIL;
636 done = TRUE;
637 }
638 }
639 }
640
641 /* End the SMTP conversation and close the connection. */
642
c9bdd01c 643 if (send_quit) (void)smtp_write_command(&outblock, FALSE, "QUIT\r\n");
059ec3d9
PH
644 close(inblock.sock);
645 } /* Loop through all hosts, while !done */
646
647/* If we get here with done == TRUE, a successful callout happened, and yield
648will be set OK or FAIL according to the response to the RCPT command.
649Otherwise, we looped through the hosts but couldn't complete the business.
650However, there may be domain-specific information to cache in both cases.
651
652The value of the result field in the new_domain record is ccache_unknown if
653there was an error before or with MAIL FROM:<>, and errno was not zero,
654implying some kind of I/O error. We don't want to write the cache in that case.
655Otherwise the value is ccache_accept or ccache_reject. */
656
657if (!callout_no_cache && new_domain_record.result != ccache_unknown)
658 {
659 if ((dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE))
660 == NULL)
661 {
662 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
663 }
664 else
665 {
666 (void)dbfn_write(dbm_file, addr->domain, &new_domain_record,
667 (int)sizeof(dbdata_callout_cache));
668 HDEBUG(D_verify) debug_printf("wrote callout cache domain record:\n"
669 " result=%d postmaster=%d random=%d\n",
670 new_domain_record.result,
671 new_domain_record.postmaster_result,
672 new_domain_record.random_result);
673 }
674 }
675
676/* If a definite result was obtained for the callout, cache it unless caching
677is disabled. */
678
679if (done)
680 {
681 if (!callout_no_cache && new_address_record.result != ccache_unknown)
682 {
683 if (dbm_file == NULL)
684 dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE);
685 if (dbm_file == NULL)
686 {
687 HDEBUG(D_verify) debug_printf("no callout cache available\n");
688 }
689 else
690 {
691 (void)dbfn_write(dbm_file, address_key, &new_address_record,
692 (int)sizeof(dbdata_callout_cache_address));
693 HDEBUG(D_verify) debug_printf("wrote %s callout cache address record\n",
694 (new_address_record.result == ccache_accept)? "positive" : "negative");
695 }
696 }
697 } /* done */
698
699/* Failure to connect to any host, or any response other than 2xx or 5xx is a
700temporary error. If there was only one host, and a response was received, leave
701it alone if supplying details. Otherwise, give a generic response. */
702
703else /* !done */
704 {
705 uschar *dullmsg = string_sprintf("Could not complete %s verify callout",
706 is_recipient? "recipient" : "sender");
707 yield = DEFER;
708
709 if (host_list->next != NULL || addr->message == NULL) addr->message = dullmsg;
710
711 addr->user_message = (!smtp_return_error_details)? dullmsg :
712 string_sprintf("%s for <%s>.\n"
713 "The mail server(s) for the domain may be temporarily unreachable, or\n"
714 "they may be permanently unreachable from this server. In the latter case,\n%s",
715 dullmsg, addr->address,
716 is_recipient?
717 "the address will never be accepted."
718 :
719 "you need to change the address or create an MX record for its domain\n"
720 "if it is supposed to be generally accessible from the Internet.\n"
721 "Talk to your mail administrator for details.");
722
723 /* Force a specific error code */
724
725 addr->basic_errno = ERRNO_CALLOUTDEFER;
726 }
727
728/* Come here from within the cache-reading code on fast-track exit. */
729
730END_CALLOUT:
731if (dbm_file != NULL) dbfn_close(dbm_file);
732return yield;
733}
734
735
736
737/*************************************************
738* Copy error to toplevel address *
739*************************************************/
740
741/* This function is used when a verify fails or defers, to ensure that the
742failure or defer information is in the original toplevel address. This applies
743when an address is redirected to a single new address, and the failure or
744deferral happens to the child address.
745
746Arguments:
747 vaddr the verify address item
748 addr the final address item
749 yield FAIL or DEFER
750
751Returns: the value of YIELD
752*/
753
754static int
755copy_error(address_item *vaddr, address_item *addr, int yield)
756{
757if (addr != vaddr)
758 {
759 vaddr->message = addr->message;
760 vaddr->user_message = addr->user_message;
761 vaddr->basic_errno = addr->basic_errno;
762 vaddr->more_errno = addr->more_errno;
763 }
764return yield;
765}
766
767
768
769
770/*************************************************
771* Verify an email address *
772*************************************************/
773
774/* This function is used both for verification (-bv and at other times) and
775address testing (-bt), which is indicated by address_test_mode being set.
776
777Arguments:
778 vaddr contains the address to verify; the next field in this block
779 must be NULL
780 f if not NULL, write the result to this file
781 options various option bits:
782 vopt_fake_sender => this sender verify is not for the real
783 sender (it was verify=sender=xxxx or an address from a
784 header line) - rewriting must not change sender_address
785 vopt_is_recipient => this is a recipient address, otherwise
786 it's a sender address - this affects qualification and
787 rewriting and messages from callouts
788 vopt_qualify => qualify an unqualified address; else error
789 vopt_expn => called from SMTP EXPN command
790
791 These ones are used by do_callout() -- the options variable
792 is passed to it.
793
794 vopt_callout_no_cache => don't use callout cache
795 vopt_callout_random => do the "random" thing
796 vopt_callout_recipsender => use real sender for recipient
797 vopt_callout_recippmaster => use postmaster for recipient
798
799 callout if > 0, specifies that callout is required, and gives timeout
4deaf07d 800 for individual commands
059ec3d9
PH
801 callout_overall if > 0, gives overall timeout for the callout function;
802 if < 0, a default is used (see do_callout())
8e669ac1 803 callout_connect the connection timeout for callouts
059ec3d9
PH
804 se_mailfrom when callout is requested to verify a sender, use this
805 in MAIL FROM; NULL => ""
806 pm_mailfrom when callout is requested, if non-NULL, do the postmaster
807 thing and use this as the sender address (may be "")
808
809 routed if not NULL, set TRUE if routing succeeded, so we can
810 distinguish between routing failed and callout failed
811
812Returns: OK address verified
813 FAIL address failed to verify
814 DEFER can't tell at present
815*/
816
817int
818verify_address(address_item *vaddr, FILE *f, int options, int callout,
8e669ac1 819 int callout_overall, int callout_connect, uschar *se_mailfrom,
4deaf07d 820 uschar *pm_mailfrom, BOOL *routed)
059ec3d9
PH
821{
822BOOL allok = TRUE;
823BOOL full_info = (f == NULL)? FALSE : (debug_selector != 0);
824BOOL is_recipient = (options & vopt_is_recipient) != 0;
825BOOL expn = (options & vopt_expn) != 0;
059ec3d9
PH
826int i;
827int yield = OK;
828int verify_type = expn? v_expn :
829 address_test_mode? v_none :
830 is_recipient? v_recipient : v_sender;
831address_item *addr_list;
832address_item *addr_new = NULL;
833address_item *addr_remote = NULL;
834address_item *addr_local = NULL;
835address_item *addr_succeed = NULL;
8e669ac1 836uschar **failure_ptr = is_recipient?
2c7db3f5 837 &recipient_verify_failure : &sender_verify_failure;
059ec3d9
PH
838uschar *ko_prefix, *cr;
839uschar *address = vaddr->address;
840uschar *save_sender;
841uschar null_sender[] = { 0 }; /* Ensure writeable memory */
842
2c7db3f5
PH
843/* Clear, just in case */
844
845*failure_ptr = NULL;
846
059ec3d9
PH
847/* Set up a prefix and suffix for error message which allow us to use the same
848output statements both in EXPN mode (where an SMTP response is needed) and when
849debugging with an output file. */
850
851if (expn)
852 {
853 ko_prefix = US"553 ";
854 cr = US"\r";
855 }
856else ko_prefix = cr = US"";
857
858/* Add qualify domain if permitted; otherwise an unqualified address fails. */
859
860if (parse_find_at(address) == NULL)
861 {
862 if ((options & vopt_qualify) == 0)
863 {
864 if (f != NULL)
865 fprintf(f, "%sA domain is required for \"%s\"%s\n", ko_prefix, address,
866 cr);
8e669ac1 867 *failure_ptr = US"qualify";
059ec3d9
PH
868 return FAIL;
869 }
870 address = rewrite_address_qualify(address, is_recipient);
871 }
872
873DEBUG(D_verify)
874 {
875 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
876 debug_printf("%s %s\n", address_test_mode? "Testing" : "Verifying", address);
877 }
878
879/* Rewrite and report on it. Clear the domain and local part caches - these
880may have been set by domains and local part tests during an ACL. */
881
882if (global_rewrite_rules != NULL)
883 {
884 uschar *old = address;
885 address = rewrite_address(address, is_recipient, FALSE,
886 global_rewrite_rules, rewrite_existflags);
887 if (address != old)
888 {
889 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->localpart_cache[i] = 0;
890 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->domain_cache[i] = 0;
891 if (f != NULL && !expn) fprintf(f, "Address rewritten as: %s\n", address);
892 }
893 }
894
895/* If this is the real sender address, we must update sender_address at
896this point, because it may be referred to in the routers. */
897
898if ((options & (vopt_fake_sender|vopt_is_recipient)) == 0)
899 sender_address = address;
900
901/* If the address was rewritten to <> no verification can be done, and we have
902to return OK. This rewriting is permitted only for sender addresses; for other
903addresses, such rewriting fails. */
904
905if (address[0] == 0) return OK;
906
907/* Save a copy of the sender address for re-instating if we change it to <>
908while verifying a sender address (a nice bit of self-reference there). */
909
910save_sender = sender_address;
911
912/* Update the address structure with the possibly qualified and rewritten
913address. Set it up as the starting address on the chain of new addresses. */
914
915vaddr->address = address;
916addr_new = vaddr;
917
918/* We need a loop, because an address can generate new addresses. We must also
919cope with generated pipes and files at the top level. (See also the code and
920comment in deliver.c.) However, it is usually the case that the router for
921user's .forward files has its verify flag turned off.
922
923If an address generates more than one child, the loop is used only when
924full_info is set, and this can only be set locally. Remote enquiries just get
925information about the top level address, not anything that it generated. */
926
927while (addr_new != NULL)
928 {
929 int rc;
930 address_item *addr = addr_new;
931
932 addr_new = addr->next;
933 addr->next = NULL;
934
935 DEBUG(D_verify)
936 {
937 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
938 debug_printf("Considering %s\n", addr->address);
939 }
940
941 /* Handle generated pipe, file or reply addresses. We don't get these
942 when handling EXPN, as it does only one level of expansion. */
943
944 if (testflag(addr, af_pfr))
945 {
946 allok = FALSE;
947 if (f != NULL)
948 {
949 BOOL allow;
950
951 if (addr->address[0] == '>')
952 {
953 allow = testflag(addr, af_allow_reply);
954 fprintf(f, "%s -> mail %s", addr->parent->address, addr->address + 1);
955 }
956 else
957 {
958 allow = (addr->address[0] == '|')?
959 testflag(addr, af_allow_pipe) : testflag(addr, af_allow_file);
960 fprintf(f, "%s -> %s", addr->parent->address, addr->address);
961 }
962
963 if (addr->basic_errno == ERRNO_BADTRANSPORT)
964 fprintf(f, "\n*** Error in setting up pipe, file, or autoreply:\n"
965 "%s\n", addr->message);
966 else if (allow)
967 fprintf(f, "\n transport = %s\n", addr->transport->name);
968 else
969 fprintf(f, " *** forbidden ***\n");
970 }
971 continue;
972 }
973
974 /* Just in case some router parameter refers to it. */
975
976 return_path = (addr->p.errors_address != NULL)?
977 addr->p.errors_address : sender_address;
978
979 /* Split the address into domain and local part, handling the %-hack if
980 necessary, and then route it. While routing a sender address, set
981 $sender_address to <> because that is what it will be if we were trying to
982 send a bounce to the sender. */
983
984 if (routed != NULL) *routed = FALSE;
985 if ((rc = deliver_split_address(addr)) == OK)
986 {
987 if (!is_recipient) sender_address = null_sender;
988 rc = route_address(addr, &addr_local, &addr_remote, &addr_new,
989 &addr_succeed, verify_type);
990 sender_address = save_sender; /* Put back the real sender */
991 }
992
993 /* If routing an address succeeded, set the flag that remembers, for use when
994 an ACL cached a sender verify (in case a callout fails). Then if routing set
995 up a list of hosts or the transport has a host list, and the callout option
996 is set, and we aren't in a host checking run, do the callout verification,
997 and set another flag that notes that a callout happened. */
998
999 if (rc == OK)
1000 {
1001 if (routed != NULL) *routed = TRUE;
1002 if (callout > 0)
1003 {
1004 host_item *host_list = addr->host_list;
1005
1006 /* Default, if no remote transport, to NULL for the interface (=> any),
1007 "smtp" for the port, and "smtp" for the protocol. */
1008
1009 transport_feedback tf = { NULL, US"smtp", US"smtp", NULL, FALSE, FALSE };
1010
1011 /* If verification yielded a remote transport, we want to use that
1012 transport's options, so as to mimic what would happen if we were really
1013 sending a message to this address. */
1014
1015 if (addr->transport != NULL && !addr->transport->info->local)
1016 {
1017 (void)(addr->transport->setup)(addr->transport, addr, &tf, NULL);
1018
1019 /* If the transport has hosts and the router does not, or if the
1020 transport is configured to override the router's hosts, we must build a
1021 host list of the transport's hosts, and find the IP addresses */
1022
1023 if (tf.hosts != NULL && (host_list == NULL || tf.hosts_override))
1024 {
1025 uschar *s;
1026
1027 host_list = NULL; /* Ignore the router's hosts */
1028
1029 deliver_domain = addr->domain;
1030 deliver_localpart = addr->local_part;
1031 s = expand_string(tf.hosts);
1032 deliver_domain = deliver_localpart = NULL;
1033
1034 if (s == NULL)
1035 {
1036 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand list of hosts "
1037 "\"%s\" in %s transport for callout: %s", tf.hosts,
1038 addr->transport->name, expand_string_message);
1039 }
1040 else
1041 {
1042 uschar *canonical_name;
d8ef3577 1043 host_item *host, *nexthost;
059ec3d9
PH
1044 host_build_hostlist(&host_list, s, tf.hosts_randomize);
1045
1046 /* Just ignore failures to find a host address. If we don't manage
8e669ac1
PH
1047 to find any addresses, the callout will defer. Note that more than
1048 one address may be found for a single host, which will result in
1049 additional host items being inserted into the chain. Hence we must
d8ef3577 1050 save the next host first. */
059ec3d9 1051
d8ef3577 1052 for (host = host_list; host != NULL; host = nexthost)
059ec3d9 1053 {
d8ef3577 1054 nexthost = host->next;
8e669ac1 1055 if (tf.gethostbyname ||
a5a28604 1056 string_is_ip_address(host->name, NULL) > 0)
059ec3d9
PH
1057 (void)host_find_byname(host, NULL, &canonical_name, TRUE);
1058 else
1059 {
1060 int flags = HOST_FIND_BY_A;
1061 if (tf.qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
1062 if (tf.search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
1063 (void)host_find_bydns(host, NULL, flags, NULL, NULL, NULL,
1064 &canonical_name, NULL);
1065 }
1066 }
1067 }
1068 }
1069 }
1070
8e669ac1 1071 /* Can only do a callout if we have at least one host! If the callout
2c7db3f5 1072 fails, it will have set ${sender,recipient}_verify_failure. */
059ec3d9
PH
1073
1074 if (host_list != NULL)
1075 {
1076 HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n");
1077 if (host_checking && !host_checking_callout)
1078 {
1079 HDEBUG(D_verify)
1080 debug_printf("... callout omitted by default when host testing\n"
1081 "(Use -bhc if you want the callouts to happen.)\n");
1082 }
1083 else
1084 {
1085 rc = do_callout(addr, host_list, &tf, callout, callout_overall,
4deaf07d 1086 callout_connect, options, se_mailfrom, pm_mailfrom);
059ec3d9
PH
1087 }
1088 }
1089 else
1090 {
1091 HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor "
1092 "transport provided a host list\n");
1093 }
1094 }
1095 }
8e669ac1 1096
2c7db3f5 1097 /* Otherwise, any failure is a routing failure */
8e669ac1
PH
1098
1099 else *failure_ptr = US"route";
059ec3d9
PH
1100
1101 /* A router may return REROUTED if it has set up a child address as a result
1102 of a change of domain name (typically from widening). In this case we always
1103 want to continue to verify the new child. */
1104
1105 if (rc == REROUTED) continue;
8e669ac1 1106
059ec3d9
PH
1107 /* Handle hard failures */
1108
1109 if (rc == FAIL)
1110 {
1111 allok = FALSE;
1112 if (f != NULL)
1113 {
1114 fprintf(f, "%s%s %s", ko_prefix, address,
1115 address_test_mode? "is undeliverable" : "failed to verify");
1116 if (!expn && admin_user)
1117 {
1118 if (addr->basic_errno > 0)
1119 fprintf(f, ": %s", strerror(addr->basic_errno));
1120 if (addr->message != NULL)
1121 fprintf(f, ":\n %s", addr->message);
1122 }
1123 fprintf(f, "%s\n", cr);
1124 }
1125
1126 if (!full_info) return copy_error(vaddr, addr, FAIL);
1127 else yield = FAIL;
1128 }
1129
1130 /* Soft failure */
1131
1132 else if (rc == DEFER)
1133 {
1134 allok = FALSE;
1135 if (f != NULL)
1136 {
1137 fprintf(f, "%s%s cannot be resolved at this time", ko_prefix, address);
1138 if (!expn && admin_user)
1139 {
1140 if (addr->basic_errno > 0)
1141 fprintf(f, ":\n %s", strerror(addr->basic_errno));
1142 if (addr->message != NULL)
1143 fprintf(f, ":\n %s", addr->message);
1144 else if (addr->basic_errno <= 0)
1145 fprintf(f, ":\n unknown error");
1146 }
1147
1148 fprintf(f, "%s\n", cr);
1149 }
1150 if (!full_info) return copy_error(vaddr, addr, DEFER);
1151 else if (yield == OK) yield = DEFER;
1152 }
1153
1154 /* If we are handling EXPN, we do not want to continue to route beyond
1155 the top level. */
1156
1157 else if (expn)
1158 {
1159 uschar *ok_prefix = US"250-";
1160 if (addr_new == NULL)
1161 {
1162 if (addr_local == NULL && addr_remote == NULL)
1163 fprintf(f, "250 mail to <%s> is discarded\r\n", address);
1164 else
1165 fprintf(f, "250 <%s>\r\n", address);
1166 }
1167 else while (addr_new != NULL)
1168 {
1169 address_item *addr2 = addr_new;
1170 addr_new = addr2->next;
1171 if (addr_new == NULL) ok_prefix = US"250 ";
1172 fprintf(f, "%s<%s>\r\n", ok_prefix, addr2->address);
1173 }
1174 return OK;
1175 }
1176
1177 /* Successful routing other than EXPN. */
1178
1179 else
1180 {
1181 /* Handle successful routing when short info wanted. Otherwise continue for
1182 other (generated) addresses. Short info is the operational case. Full info
1183 can be requested only when debug_selector != 0 and a file is supplied.
1184
1185 There is a conflict between the use of aliasing as an alternate email
1186 address, and as a sort of mailing list. If an alias turns the incoming
1187 address into just one address (e.g. J.Caesar->jc44) you may well want to
1188 carry on verifying the generated address to ensure it is valid when
1189 checking incoming mail. If aliasing generates multiple addresses, you
1190 probably don't want to do this. Exim therefore treats the generation of
1191 just a single new address as a special case, and continues on to verify the
1192 generated address. */
1193
1194 if (!full_info && /* Stop if short info wanted AND */
1195 (addr_new == NULL || /* No new address OR */
1196 addr_new->next != NULL || /* More than one new address OR */
1197 testflag(addr_new, af_pfr))) /* New address is pfr */
1198 {
1199 if (f != NULL) fprintf(f, "%s %s\n", address,
1200 address_test_mode? "is deliverable" : "verified");
1201
1202 /* If we have carried on to verify a child address, we want the value
1203 of $address_data to be that of the child */
1204
1205 vaddr->p.address_data = addr->p.address_data;
1206 return OK;
1207 }
1208 }
1209 } /* Loop for generated addresses */
1210
1211/* Display the full results of the successful routing, including any generated
1212addresses. Control gets here only when full_info is set, which requires f not
1213to be NULL, and this occurs only when a top-level verify is called with the
1214debugging switch on.
1215
1216If there are no local and no remote addresses, and there were no pipes, files,
1217or autoreplies, and there were no errors or deferments, the message is to be
1218discarded, usually because of the use of :blackhole: in an alias file. */
1219
1220if (allok && addr_local == NULL && addr_remote == NULL)
1221 fprintf(f, "mail to %s is discarded\n", address);
1222
1223else for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++)
1224 {
1225 while (addr_list != NULL)
1226 {
1227 address_item *addr = addr_list;
1228 address_item *p = addr->parent;
1229 addr_list = addr->next;
1230
1231 fprintf(f, "%s", CS addr->address);
384152a6
TK
1232#ifdef EXPERIMENTAL_SRS
1233 if(addr->p.srs_sender)
1234 fprintf(f, " [srs = %s]", addr->p.srs_sender);
1235#endif
059ec3d9
PH
1236 while (p != NULL)
1237 {
1238 fprintf(f, "\n <-- %s", p->address);
1239 p = p->parent;
1240 }
1241 fprintf(f, "\n ");
1242
1243 /* Show router, and transport */
1244
1245 fprintf(f, "router = %s, ", addr->router->name);
1246 fprintf(f, "transport = %s\n", (addr->transport == NULL)? US"unset" :
1247 addr->transport->name);
1248
1249 /* Show any hosts that are set up by a router unless the transport
1250 is going to override them; fiddle a bit to get a nice format. */
1251
1252 if (addr->host_list != NULL && addr->transport != NULL &&
1253 !addr->transport->overrides_hosts)
1254 {
1255 host_item *h;
1256 int maxlen = 0;
1257 int maxaddlen = 0;
1258 for (h = addr->host_list; h != NULL; h = h->next)
1259 {
1260 int len = Ustrlen(h->name);
1261 if (len > maxlen) maxlen = len;
1262 len = (h->address != NULL)? Ustrlen(h->address) : 7;
1263 if (len > maxaddlen) maxaddlen = len;
1264 }
1265 for (h = addr->host_list; h != NULL; h = h->next)
1266 {
1267 int len = Ustrlen(h->name);
1268 fprintf(f, " host %s ", h->name);
1269 while (len++ < maxlen) fprintf(f, " ");
1270 if (h->address != NULL)
1271 {
1272 fprintf(f, "[%s] ", h->address);
1273 len = Ustrlen(h->address);
1274 }
1275 else if (!addr->transport->info->local) /* Omit [unknown] for local */
1276 {
1277 fprintf(f, "[unknown] ");
1278 len = 7;
1279 }
1280 else len = -3;
1281 while (len++ < maxaddlen) fprintf(f," ");
1282 if (h->mx >= 0) fprintf(f, "MX=%d", h->mx);
1283 if (h->port != PORT_NONE) fprintf(f, " port=%d", h->port);
1284 if (h->status == hstatus_unusable) fprintf(f, " ** unusable **");
1285 fprintf(f, "\n");
1286 }
1287 }
1288 }
1289 }
1290
8e669ac1 1291/* Will be DEFER or FAIL if any one address has, only for full_info (which is
2c7db3f5
PH
1292the -bv or -bt case). */
1293
8e669ac1 1294return yield;
059ec3d9
PH
1295}
1296
1297
1298
1299
1300/*************************************************
1301* Check headers for syntax errors *
1302*************************************************/
1303
1304/* This function checks those header lines that contain addresses, and verifies
1305that all the addresses therein are syntactially correct.
1306
1307Arguments:
1308 msgptr where to put an error message
1309
1310Returns: OK
1311 FAIL
1312*/
1313
1314int
1315verify_check_headers(uschar **msgptr)
1316{
1317header_line *h;
1318uschar *colon, *s;
1319
1320for (h = header_list; h != NULL; h = h->next)
1321 {
1322 if (h->type != htype_from &&
1323 h->type != htype_reply_to &&
1324 h->type != htype_sender &&
1325 h->type != htype_to &&
1326 h->type != htype_cc &&
1327 h->type != htype_bcc)
1328 continue;
1329
1330 colon = Ustrchr(h->text, ':');
1331 s = colon + 1;
1332 while (isspace(*s)) s++;
1333
1334 parse_allow_group = TRUE; /* Allow group syntax */
1335
1336 /* Loop for multiple addresses in the header */
1337
1338 while (*s != 0)
1339 {
1340 uschar *ss = parse_find_address_end(s, FALSE);
1341 uschar *recipient, *errmess;
1342 int terminator = *ss;
1343 int start, end, domain;
1344
1345 /* Temporarily terminate the string at this point, and extract the
1346 operative address within. */
1347
1348 *ss = 0;
1349 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
1350 *ss = terminator;
1351
1352 /* Permit an unqualified address only if the message is local, or if the
1353 sending host is configured to be permitted to send them. */
1354
1355 if (recipient != NULL && domain == 0)
1356 {
1357 if (h->type == htype_from || h->type == htype_sender)
1358 {
1359 if (!allow_unqualified_sender) recipient = NULL;
1360 }
1361 else
1362 {
1363 if (!allow_unqualified_recipient) recipient = NULL;
1364 }
1365 if (recipient == NULL) errmess = US"unqualified address not permitted";
1366 }
1367
1368 /* It's an error if no address could be extracted, except for the special
1369 case of an empty address. */
1370
1371 if (recipient == NULL && Ustrcmp(errmess, "empty address") != 0)
1372 {
1373 uschar *verb = US"is";
1374 uschar *t = ss;
1375 int len;
1376
1377 /* Arrange not to include any white space at the end in the
1378 error message. */
1379
1380 while (t > s && isspace(t[-1])) t--;
1381
1382 /* Add the address which failed to the error message, since in a
1383 header with very many addresses it is sometimes hard to spot
1384 which one is at fault. However, limit the amount of address to
1385 quote - cases have been seen where, for example, a missing double
1386 quote in a humungous To: header creates an "address" that is longer
1387 than string_sprintf can handle. */
1388
1389 len = t - s;
1390 if (len > 1024)
1391 {
1392 len = 1024;
1393 verb = US"begins";
1394 }
1395
1396 *msgptr = string_printing(
1397 string_sprintf("%s: failing address in \"%.*s\" header %s: %.*s",
1398 errmess, colon - h->text, h->text, verb, len, s));
1399
1400 return FAIL;
1401 }
1402
1403 /* Advance to the next address */
1404
1405 s = ss + (terminator? 1:0);
1406 while (isspace(*s)) s++;
1407 } /* Next address */
1408 } /* Next header */
1409
1410return OK;
1411}
1412
1413
1414
1415
1416/*************************************************
1417* Find if verified sender *
1418*************************************************/
1419
1420/* Usually, just a single address is verified as the sender of the message.
1421However, Exim can be made to verify other addresses as well (often related in
1422some way), and this is useful in some environments. There may therefore be a
1423chain of such addresses that have previously been tested. This function finds
1424whether a given address is on the chain.
1425
1426Arguments: the address to be verified
1427Returns: pointer to an address item, or NULL
1428*/
1429
1430address_item *
1431verify_checked_sender(uschar *sender)
1432{
1433address_item *addr;
1434for (addr = sender_verified_list; addr != NULL; addr = addr->next)
1435 if (Ustrcmp(sender, addr->address) == 0) break;
1436return addr;
1437}
1438
1439
1440
1441
1442
1443/*************************************************
1444* Get valid header address *
1445*************************************************/
1446
1447/* Scan the originator headers of the message, looking for an address that
1448verifies successfully. RFC 822 says:
1449
1450 o The "Sender" field mailbox should be sent notices of
1451 any problems in transport or delivery of the original
1452 messages. If there is no "Sender" field, then the
1453 "From" field mailbox should be used.
1454
1455 o If the "Reply-To" field exists, then the reply should
1456 go to the addresses indicated in that field and not to
1457 the address(es) indicated in the "From" field.
1458
1459So we check a Sender field if there is one, else a Reply_to field, else a From
1460field. As some strange messages may have more than one of these fields,
1461especially if they are resent- fields, check all of them if there is more than
1462one.
1463
1464Arguments:
1465 user_msgptr points to where to put a user error message
1466 log_msgptr points to where to put a log error message
1467 callout timeout for callout check (passed to verify_address())
1468 callout_overall overall callout timeout (ditto)
8e669ac1 1469 callout_connect connect callout timeout (ditto)
059ec3d9
PH
1470 se_mailfrom mailfrom for verify; NULL => ""
1471 pm_mailfrom sender for pm callout check (passed to verify_address())
1472 options callout options (passed to verify_address())
8e669ac1 1473 verrno where to put the address basic_errno
059ec3d9
PH
1474
1475If log_msgptr is set to something without setting user_msgptr, the caller
1476normally uses log_msgptr for both things.
1477
1478Returns: result of the verification attempt: OK, FAIL, or DEFER;
1479 FAIL is given if no appropriate headers are found
1480*/
1481
1482int
1483verify_check_header_address(uschar **user_msgptr, uschar **log_msgptr,
8e669ac1 1484 int callout, int callout_overall, int callout_connect, uschar *se_mailfrom,
fe5b5d0b 1485 uschar *pm_mailfrom, int options, int *verrno)
059ec3d9
PH
1486{
1487static int header_types[] = { htype_sender, htype_reply_to, htype_from };
1488int yield = FAIL;
1489int i;
1490
1491for (i = 0; i < 3; i++)
1492 {
1493 header_line *h;
1494 for (h = header_list; h != NULL; h = h->next)
1495 {
1496 int terminator, new_ok;
1497 uschar *s, *ss, *endname;
1498
1499 if (h->type != header_types[i]) continue;
1500 s = endname = Ustrchr(h->text, ':') + 1;
1501
1502 while (*s != 0)
1503 {
1504 address_item *vaddr;
1505
1506 while (isspace(*s) || *s == ',') s++;
1507 if (*s == 0) break; /* End of header */
1508
1509 ss = parse_find_address_end(s, FALSE);
1510
1511 /* The terminator is a comma or end of header, but there may be white
1512 space preceding it (including newline for the last address). Move back
1513 past any white space so we can check against any cached envelope sender
1514 address verifications. */
1515
1516 while (isspace(ss[-1])) ss--;
1517 terminator = *ss;
1518 *ss = 0;
1519
1520 HDEBUG(D_verify) debug_printf("verifying %.*s header address %s\n",
1521 (int)(endname - h->text), h->text, s);
1522
1523 /* See if we have already verified this address as an envelope sender,
1524 and if so, use the previous answer. */
1525
1526 vaddr = verify_checked_sender(s);
1527
1528 if (vaddr != NULL && /* Previously checked */
1529 (callout <= 0 || /* No callout needed; OR */
1530 vaddr->special_action > 256)) /* Callout was done */
1531 {
1532 new_ok = vaddr->special_action & 255;
1533 HDEBUG(D_verify) debug_printf("previously checked as envelope sender\n");
1534 *ss = terminator; /* Restore shortened string */
1535 }
1536
1537 /* Otherwise we run the verification now. We must restore the shortened
1538 string before running the verification, so the headers are correct, in
1539 case there is any rewriting. */
1540
1541 else
1542 {
1543 int start, end, domain;
1544 uschar *address = parse_extract_address(s, log_msgptr, &start,
1545 &end, &domain, FALSE);
1546
1547 *ss = terminator;
1548
1549 /* If verification failed because of a syntax error, fail this
1550 function, and ensure that the failing address gets added to the error
1551 message. */
1552
1553 if (address == NULL)
1554 {
1555 new_ok = FAIL;
1556 if (*log_msgptr != NULL)
1557 {
1558 while (ss > s && isspace(ss[-1])) ss--;
1559 *log_msgptr = string_sprintf("syntax error in '%.*s' header when "
1560 "scanning for sender: %s in \"%.*s\"",
1561 endname - h->text, h->text, *log_msgptr, ss - s, s);
1562 return FAIL;
1563 }
1564 }
1565
2f6603e1 1566 /* Else go ahead with the sender verification. But it isn't *the*
059ec3d9
PH
1567 sender of the message, so set vopt_fake_sender to stop sender_address
1568 being replaced after rewriting or qualification. */
1569
1570 else
1571 {
1572 vaddr = deliver_make_addr(address, FALSE);
1573 new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender,
8e669ac1 1574 callout, callout_overall, callout_connect, se_mailfrom,
4deaf07d 1575 pm_mailfrom, NULL);
059ec3d9
PH
1576 }
1577 }
1578
1579 /* We now have the result, either newly found, or cached. If we are
1580 giving out error details, set a specific user error. This means that the
1581 last of these will be returned to the user if all three fail. We do not
1582 set a log message - the generic one below will be used. */
1583
fe5b5d0b 1584 if (new_ok != OK)
059ec3d9 1585 {
8e669ac1 1586 *verrno = vaddr->basic_errno;
fe5b5d0b
PH
1587 if (smtp_return_error_details)
1588 {
1589 *user_msgptr = string_sprintf("Rejected after DATA: "
1590 "could not verify \"%.*s\" header address\n%s: %s",
1591 endname - h->text, h->text, vaddr->address, vaddr->message);
1592 }
8e669ac1 1593 }
059ec3d9
PH
1594
1595 /* Success or defer */
1596
1597 if (new_ok == OK) return OK;
1598 if (new_ok == DEFER) yield = DEFER;
1599
1600 /* Move on to any more addresses in the header */
1601
1602 s = ss;
1603 }
1604 }
1605 }
1606
1607if (yield == FAIL && *log_msgptr == NULL)
1608 *log_msgptr = US"there is no valid sender in any header line";
1609
1610if (yield == DEFER && *log_msgptr == NULL)
1611 *log_msgptr = US"all attempts to verify a sender in a header line deferred";
1612
1613return yield;
1614}
1615
1616
1617
1618
1619/*************************************************
1620* Get RFC 1413 identification *
1621*************************************************/
1622
1623/* Attempt to get an id from the sending machine via the RFC 1413 protocol. If
1624the timeout is set to zero, then the query is not done. There may also be lists
1625of hosts and nets which are exempt. To guard against malefactors sending
1626non-printing characters which could, for example, disrupt a message's headers,
1627make sure the string consists of printing characters only.
1628
1629Argument:
1630 port the port to connect to; usually this is IDENT_PORT (113), but when
1631 running in the test harness with -bh a different value is used.
1632
1633Returns: nothing
1634
1635Side effect: any received ident value is put in sender_ident (NULL otherwise)
1636*/
1637
1638void
1639verify_get_ident(int port)
1640{
1641int sock, host_af, qlen;
1642int received_sender_port, received_interface_port, n;
1643uschar *p;
1644uschar buffer[2048];
1645
1646/* Default is no ident. Check whether we want to do an ident check for this
1647host. */
1648
1649sender_ident = NULL;
1650if (rfc1413_query_timeout <= 0 || verify_check_host(&rfc1413_hosts) != OK)
1651 return;
1652
1653DEBUG(D_ident) debug_printf("doing ident callback\n");
1654
1655/* Set up a connection to the ident port of the remote host. Bind the local end
1656to the incoming interface address. If the sender host address is an IPv6
1657address, the incoming interface address will also be IPv6. */
1658
1659host_af = (Ustrchr(sender_host_address, ':') == NULL)? AF_INET : AF_INET6;
1660sock = ip_socket(SOCK_STREAM, host_af);
1661if (sock < 0) return;
1662
1663if (ip_bind(sock, host_af, interface_address, 0) < 0)
1664 {
1665 DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n",
1666 strerror(errno));
1667 goto END_OFF;
1668 }
1669
1670if (ip_connect(sock, host_af, sender_host_address, port, rfc1413_query_timeout)
1671 < 0)
1672 {
1673 if (errno == ETIMEDOUT && (log_extra_selector & LX_ident_timeout) != 0)
1674 {
1675 log_write(0, LOG_MAIN, "ident connection to %s timed out",
1676 sender_host_address);
1677 }
1678 else
1679 {
1680 DEBUG(D_ident) debug_printf("ident connection to %s failed: %s\n",
1681 sender_host_address, strerror(errno));
1682 }
1683 goto END_OFF;
1684 }
1685
1686/* Construct and send the query. */
1687
1688sprintf(CS buffer, "%d , %d\r\n", sender_host_port, interface_port);
1689qlen = Ustrlen(buffer);
1690if (send(sock, buffer, qlen, 0) < 0)
1691 {
1692 DEBUG(D_ident) debug_printf("ident send failed: %s\n", strerror(errno));
1693 goto END_OFF;
1694 }
1695
1696/* Read a response line. We put it into the rest of the buffer, using several
1697recv() calls if necessary. */
1698
1699p = buffer + qlen;
1700
1701for (;;)
1702 {
1703 uschar *pp;
1704 int count;
1705 int size = sizeof(buffer) - (p - buffer);
1706
1707 if (size <= 0) goto END_OFF; /* Buffer filled without seeing \n. */
1708 count = ip_recv(sock, p, size, rfc1413_query_timeout);
1709 if (count <= 0) goto END_OFF; /* Read error or EOF */
1710
1711 /* Scan what we just read, to see if we have reached the terminating \r\n. Be
1712 generous, and accept a plain \n terminator as well. The only illegal
1713 character is 0. */
1714
1715 for (pp = p; pp < p + count; pp++)
1716 {
1717 if (*pp == 0) goto END_OFF; /* Zero octet not allowed */
1718 if (*pp == '\n')
1719 {
1720 if (pp[-1] == '\r') pp--;
1721 *pp = 0;
1722 goto GOT_DATA; /* Break out of both loops */
1723 }
1724 }
1725
1726 /* Reached the end of the data without finding \n. Let the loop continue to
1727 read some more, if there is room. */
1728
1729 p = pp;
1730 }
1731
1732GOT_DATA:
1733
1734/* We have received a line of data. Check it carefully. It must start with the
1735same two port numbers that we sent, followed by data as defined by the RFC. For
1736example,
1737
1738 12345 , 25 : USERID : UNIX :root
1739
1740However, the amount of white space may be different to what we sent. In the
1741"osname" field there may be several sub-fields, comma separated. The data we
1742actually want to save follows the third colon. Some systems put leading spaces
1743in it - we discard those. */
1744
1745if (sscanf(CS buffer + qlen, "%d , %d%n", &received_sender_port,
1746 &received_interface_port, &n) != 2 ||
1747 received_sender_port != sender_host_port ||
1748 received_interface_port != interface_port)
1749 goto END_OFF;
1750
1751p = buffer + qlen + n;
1752while(isspace(*p)) p++;
1753if (*p++ != ':') goto END_OFF;
1754while(isspace(*p)) p++;
1755if (Ustrncmp(p, "USERID", 6) != 0) goto END_OFF;
1756p += 6;
1757while(isspace(*p)) p++;
1758if (*p++ != ':') goto END_OFF;
1759while (*p != 0 && *p != ':') p++;
1760if (*p++ == 0) goto END_OFF;
1761while(isspace(*p)) p++;
1762if (*p == 0) goto END_OFF;
1763
1764/* The rest of the line is the data we want. We turn it into printing
1765characters when we save it, so that it cannot mess up the format of any logging
1766or Received: lines into which it gets inserted. We keep a maximum of 127
1767characters. */
1768
1769sender_ident = string_printing(string_copyn(p, 127));
1770DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident);
1771
1772END_OFF:
1773close(sock);
1774return;
1775}
1776
1777
1778
1779
1780/*************************************************
1781* Match host to a single host-list item *
1782*************************************************/
1783
1784/* This function compares a host (name or address) against a single item
1785from a host list. The host name gets looked up if it is needed and is not
1786already known. The function is called from verify_check_this_host() via
1787match_check_list(), which is why most of its arguments are in a single block.
1788
1789Arguments:
1790 arg the argument block (see below)
1791 ss the host-list item
1792 valueptr where to pass back looked up data, or NULL
1793 error for error message when returning ERROR
1794
1795The block contains:
1796 host_name the host name or NULL, implying use sender_host_name and
1797 sender_host_aliases, looking them up if required
1798 host_address the host address
1799 host_ipv4 the IPv4 address taken from an IPv6 one
1800
1801Returns: OK matched
1802 FAIL did not match
1803 DEFER lookup deferred
1804 ERROR failed to find the host name or IP address
1805 unknown lookup type specified
1806*/
1807
1808static int
1809check_host(void *arg, uschar *ss, uschar **valueptr, uschar **error)
1810{
1811check_host_block *cb = (check_host_block *)arg;
1812int maskoffset;
1813BOOL isquery = FALSE;
1814uschar *semicolon, *t;
1815uschar **aliases;
1816
1817/* Optimize for the special case when the pattern is "*". */
1818
1819if (*ss == '*' && ss[1] == 0) return OK;
1820
1821/* If the pattern is empty, it matches only in the case when there is no host -
1822this can occur in ACL checking for SMTP input using the -bs option. In this
1823situation, the host address is the empty string. */
1824
1825if (cb->host_address[0] == 0) return (*ss == 0)? OK : FAIL;
1826if (*ss == 0) return FAIL;
1827
1828/* If the pattern is precisely "@" then match against the primary host name;
1829if it's "@[]" match against the local host's IP addresses. */
1830
1831if (*ss == '@')
1832 {
1833 if (ss[1] == 0) ss = primary_hostname;
1834 else if (Ustrcmp(ss, "@[]") == 0)
1835 {
1836 ip_address_item *ip;
1837 for (ip = host_find_interfaces(); ip != NULL; ip = ip->next)
1838 if (Ustrcmp(ip->address, cb->host_address) == 0) return OK;
1839 return FAIL;
1840 }
1841 }
1842
1843/* If the pattern is an IP address, optionally followed by a bitmask count, do
1844a (possibly masked) comparision with the current IP address. */
1845
a5a28604 1846if (string_is_ip_address(ss, &maskoffset) > 0)
059ec3d9
PH
1847 return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL);
1848
1849/* If the item is of the form net[n]-lookup;<file|query> then it is a lookup on
1850a masked IP network, in textual form. The net- stuff really only applies to
1851single-key lookups where the key is implicit. For query-style lookups the key
1852is specified in the query. From release 4.30, the use of net- for query style
1853is no longer needed, but we retain it for backward compatibility. */
1854
1855if (Ustrncmp(ss, "net", 3) == 0 && (semicolon = Ustrchr(ss, ';')) != NULL)
1856 {
1857 int mlen = 0;
1858 for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0';
1859 if (*t++ == '-')
1860 {
1861 int insize;
1862 int search_type;
1863 int incoming[4];
1864 void *handle;
1865 uschar *filename, *key, *result;
1866 uschar buffer[64];
1867
1868 /* If no mask was supplied, set a negative value */
1869
1870 if (mlen == 0 && t == ss+4) mlen = -1;
1871
1872 /* Find the search type */
1873
1874 search_type = search_findtype(t, semicolon - t);
1875
1876 if (search_type < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
1877 search_error_message);
1878
1879 /* Adjust parameters for the type of lookup. For a query-style
1880 lookup, there is no file name, and the "key" is just the query. For
1881 a single-key lookup, the key is the current IP address, masked
8e669ac1 1882 appropriately, and reconverted to text form, with the mask appended.
6f0c9a4f 1883 For IPv6 addresses, specify dot separators instead of colons. */
059ec3d9
PH
1884
1885 if (mac_islookup(search_type, lookup_querystyle))
1886 {
1887 filename = NULL;
1888 key = semicolon + 1;
1889 }
1890 else
1891 {
1892 insize = host_aton(cb->host_address, incoming);
1893 host_mask(insize, incoming, mlen);
6f0c9a4f 1894 (void)host_nmtoa(insize, incoming, mlen, buffer, '.');
059ec3d9
PH
1895 key = buffer;
1896 filename = semicolon + 1;
1897 }
1898
1899 /* Now do the actual lookup; note that there is no search_close() because
1900 of the caching arrangements. */
1901
1902 handle = search_open(filename, search_type, 0, NULL, NULL);
1903 if (handle == NULL) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
1904 search_error_message);
1905 result = search_find(handle, filename, key, -1, NULL, 0, 0, NULL);
1906 if (valueptr != NULL) *valueptr = result;
1907 return (result != NULL)? OK : search_find_defer? DEFER: FAIL;
1908 }
1909 }
1910
1911/* The pattern is not an IP address or network reference of any kind. That is,
1912it is a host name pattern. Check the characters of the pattern to see if they
1913comprise only letters, digits, full stops, and hyphens (the constituents of
1914domain names). Allow underscores, as they are all too commonly found. Sigh.
1915Also, if allow_utf8_domains is set, allow top-bit characters. */
1916
1917for (t = ss; *t != 0; t++)
1918 if (!isalnum(*t) && *t != '.' && *t != '-' && *t != '_' &&
1919 (!allow_utf8_domains || *t < 128)) break;
1920
1921/* If the pattern is a complete domain name, with no fancy characters, look up
1922its IP address and match against that. Note that a multi-homed host will add
1923items to the chain. */
1924
1925if (*t == 0)
1926 {
1927 int rc;
1928 host_item h;
1929 h.next = NULL;
1930 h.name = ss;
1931 h.address = NULL;
1932 h.mx = MX_NONE;
1933 rc = host_find_byname(&h, NULL, NULL, FALSE);
1934 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
1935 {
1936 host_item *hh;
1937 for (hh = &h; hh != NULL; hh = hh->next)
1938 {
1939 if (Ustrcmp(hh->address, (Ustrchr(hh->address, ':') == NULL)?
1940 cb->host_ipv4 : cb->host_address) == 0)
1941 return OK;
1942 }
1943 return FAIL;
1944 }
1945 if (rc == HOST_FIND_AGAIN) return DEFER;
1946 *error = string_sprintf("failed to find IP address for %s", ss);
1947 return ERROR;
1948 }
1949
1950/* Almost all subsequent comparisons require the host name, and can be done
1951using the general string matching function. When this function is called for
1952outgoing hosts, the name is always given explicitly. If it is NULL, it means we
1953must use sender_host_name and its aliases, looking them up if necessary. */
1954
1955if (cb->host_name != NULL) /* Explicit host name given */
1956 return match_check_string(cb->host_name, ss, -1, TRUE, TRUE, TRUE,
1957 valueptr);
1958
1959/* Host name not given; in principle we need the sender host name and its
1960aliases. However, for query-style lookups, we do not need the name if the
1961query does not contain $sender_host_name. From release 4.23, a reference to
1962$sender_host_name causes it to be looked up, so we don't need to do the lookup
1963on spec. */
1964
1965if ((semicolon = Ustrchr(ss, ';')) != NULL)
1966 {
1967 uschar *affix;
1968 int partial, affixlen, starflags, id;
1969
1970 *semicolon = 0;
1971 id = search_findtype_partial(ss, &partial, &affix, &affixlen, &starflags);
1972 *semicolon=';';
1973
1974 if (id < 0) /* Unknown lookup type */
1975 {
1976 log_write(0, LOG_MAIN|LOG_PANIC, "%s in host list item \"%s\"",
1977 search_error_message, ss);
1978 return DEFER;
1979 }
1980 isquery = mac_islookup(id, lookup_querystyle);
1981 }
1982
1983if (isquery)
1984 {
1985 switch(match_check_string(US"", ss, -1, TRUE, TRUE, TRUE, valueptr))
1986 {
1987 case OK: return OK;
1988 case DEFER: return DEFER;
1989 default: return FAIL;
1990 }
1991 }
1992
1993/* Not a query-style lookup; must ensure the host name is present, and then we
1994do a check on the name and all its aliases. */
1995
1996if (sender_host_name == NULL)
1997 {
1998 HDEBUG(D_host_lookup)
1999 debug_printf("sender host name required, to match against %s\n", ss);
2000 if (host_lookup_failed || host_name_lookup() != OK)
2001 {
2002 *error = string_sprintf("failed to find host name for %s",
2003 sender_host_address);;
2004 return ERROR;
2005 }
2006 host_build_sender_fullhost();
2007 }
2008
2009/* Match on the sender host name, using the general matching function */
2010
2011switch(match_check_string(sender_host_name, ss, -1, TRUE, TRUE, TRUE,
2012 valueptr))
2013 {
2014 case OK: return OK;
2015 case DEFER: return DEFER;
2016 }
2017
2018/* If there are aliases, try matching on them. */
2019
2020aliases = sender_host_aliases;
2021while (*aliases != NULL)
2022 {
2023 switch(match_check_string(*aliases++, ss, -1, TRUE, TRUE, TRUE, valueptr))
2024 {
2025 case OK: return OK;
2026 case DEFER: return DEFER;
2027 }
2028 }
2029return FAIL;
2030}
2031
2032
2033
2034
2035/*************************************************
2036* Check a specific host matches a host list *
2037*************************************************/
2038
2039/* This function is passed a host list containing items in a number of
2040different formats and the identity of a host. Its job is to determine whether
2041the given host is in the set of hosts defined by the list. The host name is
2042passed as a pointer so that it can be looked up if needed and not already
2043known. This is commonly the case when called from verify_check_host() to check
2044an incoming connection. When called from elsewhere the host name should usually
2045be set.
2046
2047This function is now just a front end to match_check_list(), which runs common
2048code for scanning a list. We pass it the check_host() function to perform a
2049single test.
2050
2051Arguments:
2052 listptr pointer to the host list
2053 cache_bits pointer to cache for named lists, or NULL
2054 host_name the host name or NULL, implying use sender_host_name and
2055 sender_host_aliases, looking them up if required
2056 host_address the IP address
2057 valueptr if not NULL, data from a lookup is passed back here
2058
2059Returns: OK if the host is in the defined set
2060 FAIL if the host is not in the defined set,
2061 DEFER if a data lookup deferred (not a host lookup)
2062
2063If the host name was needed in order to make a comparison, and could not be
2064determined from the IP address, the result is FAIL unless the item
2065"+allow_unknown" was met earlier in the list, in which case OK is returned. */
2066
2067int
2068verify_check_this_host(uschar **listptr, unsigned int *cache_bits,
2069 uschar *host_name, uschar *host_address, uschar **valueptr)
2070{
d4eb88df 2071int rc;
059ec3d9 2072unsigned int *local_cache_bits = cache_bits;
d4eb88df 2073uschar *save_host_address = deliver_host_address;
059ec3d9
PH
2074check_host_block cb;
2075cb.host_name = host_name;
2076cb.host_address = host_address;
2077
2078if (valueptr != NULL) *valueptr = NULL;
2079
2080/* If the host address starts off ::ffff: it is an IPv6 address in
2081IPv4-compatible mode. Find the IPv4 part for checking against IPv4
2082addresses. */
2083
2084cb.host_ipv4 = (Ustrncmp(host_address, "::ffff:", 7) == 0)?
2085 host_address + 7 : host_address;
2086
8e669ac1
PH
2087/* During the running of the check, put the IP address into $host_address. In
2088the case of calls from the smtp transport, it will already be there. However,
2089in other calls (e.g. when testing ignore_target_hosts), it won't. Just to be on
d4eb88df
PH
2090the safe side, any existing setting is preserved, though as I write this
2091(November 2004) I can't see any cases where it is actually needed. */
2092
2093deliver_host_address = host_address;
2094rc = match_check_list(
2095 listptr, /* the list */
2096 0, /* separator character */
2097 &hostlist_anchor, /* anchor pointer */
2098 &local_cache_bits, /* cache pointer */
2099 check_host, /* function for testing */
2100 &cb, /* argument for function */
2101 MCL_HOST, /* type of check */
8e669ac1 2102 (host_address == sender_host_address)?
d4eb88df
PH
2103 US"host" : host_address, /* text for debugging */
2104 valueptr); /* where to pass back data */
2105deliver_host_address = save_host_address;
8e669ac1 2106return rc;
059ec3d9
PH
2107}
2108
2109
2110
2111
2112/*************************************************
2113* Check the remote host matches a list *
2114*************************************************/
2115
2116/* This is a front end to verify_check_this_host(), created because checking
2117the remote host is a common occurrence. With luck, a good compiler will spot
2118the tail recursion and optimize it. If there's no host address, this is
2119command-line SMTP input - check against an empty string for the address.
2120
2121Arguments:
2122 listptr pointer to the host list
2123
2124Returns: the yield of verify_check_this_host(),
2125 i.e. OK, FAIL, or DEFER
2126*/
2127
2128int
2129verify_check_host(uschar **listptr)
2130{
2131return verify_check_this_host(listptr, sender_host_cache, NULL,
2132 (sender_host_address == NULL)? US"" : sender_host_address, NULL);
2133}
2134
2135
2136
2137
2138
2139/*************************************************
2140* Invert an IP address for a DNS black list *
2141*************************************************/
2142
2143/*
2144Arguments:
2145 buffer where to put the answer
2146 address the address to invert
2147*/
2148
2149static void
2150invert_address(uschar *buffer, uschar *address)
2151{
2152int bin[4];
2153uschar *bptr = buffer;
2154
2155/* If this is an IPv4 address mapped into IPv6 format, adjust the pointer
2156to the IPv4 part only. */
2157
2158if (Ustrncmp(address, "::ffff:", 7) == 0) address += 7;
2159
2160/* Handle IPv4 address: when HAVE_IPV6 is false, the result of host_aton() is
2161always 1. */
2162
2163if (host_aton(address, bin) == 1)
2164 {
2165 int i;
2166 int x = bin[0];
2167 for (i = 0; i < 4; i++)
2168 {
2169 sprintf(CS bptr, "%d.", x & 255);
2170 while (*bptr) bptr++;
2171 x >>= 8;
2172 }
2173 }
2174
2175/* Handle IPv6 address. Actually, as far as I know, there are no IPv6 addresses
2176in any DNS black lists, and the format in which they will be looked up is
2177unknown. This is just a guess. */
2178
2179#if HAVE_IPV6
2180else
2181 {
2182 int i, j;
2183 for (j = 3; j >= 0; j--)
2184 {
2185 int x = bin[j];
2186 for (i = 0; i < 8; i++)
2187 {
2188 sprintf(CS bptr, "%x.", x & 15);
2189 while (*bptr) bptr++;
2190 x >>= 4;
2191 }
2192 }
2193 }
2194#endif
2195}
2196
2197
2198
2199/*************************************************
0bcb2a0e
PH
2200* Perform a single dnsbl lookup *
2201*************************************************/
2202
2203/* This function is called from verify_check_dnsbl() below.
2204
2205Arguments:
2206 domain the outer dnsbl domain (for debug message)
8e669ac1 2207 keydomain the current keydomain (for debug message)
0bcb2a0e 2208 query the domain to be looked up
8e669ac1
PH
2209 iplist the list of matching IP addresses
2210 bitmask true if bitmask matching is wanted
2211 invert_result true if result to be inverted
2212 defer_return what to return for a defer
0bcb2a0e
PH
2213
2214Returns: OK if lookup succeeded
2215 FAIL if not
2216*/
2217
2218static int
8e669ac1 2219one_check_dnsbl(uschar *domain, uschar *keydomain, uschar *query,
0bcb2a0e 2220 uschar *iplist, BOOL bitmask, BOOL invert_result, int defer_return)
8e669ac1 2221{
0bcb2a0e
PH
2222dns_answer dnsa;
2223dns_scan dnss;
2224tree_node *t;
2225dnsbl_cache_block *cb;
2226int old_pool = store_pool;
2227
2228/* Look for this query in the cache. */
2229
2230t = tree_search(dnsbl_cache, query);
2231
2232/* If not cached from a previous lookup, we must do a DNS lookup, and
2233cache the result in permanent memory. */
2234
2235if (t == NULL)
2236 {
2237 store_pool = POOL_PERM;
2238
2239 /* Set up a tree entry to cache the lookup */
2240
2241 t = store_get(sizeof(tree_node) + Ustrlen(query));
2242 Ustrcpy(t->name, query);
2243 t->data.ptr = cb = store_get(sizeof(dnsbl_cache_block));
2244 (void)tree_insertnode(&dnsbl_cache, t);
2245
2246 /* Do the DNS loopup . */
2247
2248 HDEBUG(D_dnsbl) debug_printf("new DNS lookup for %s\n", query);
2249 cb->rc = dns_basic_lookup(&dnsa, query, T_A);
2250 cb->text_set = FALSE;
2251 cb->text = NULL;
2252 cb->rhs = NULL;
2253
2254 /* If the lookup succeeded, cache the RHS address. The code allows for
2255 more than one address - this was for complete generality and the possible
2256 use of A6 records. However, A6 records have been reduced to experimental
2257 status (August 2001) and may die out. So they may never get used at all,
2258 let alone in dnsbl records. However, leave the code here, just in case.
2259
2260 Quite apart from one A6 RR generating multiple addresses, there are DNS
2261 lists that return more than one A record, so we must handle multiple
2262 addresses generated in that way as well. */
2263
2264 if (cb->rc == DNS_SUCCEED)
2265 {
2266 dns_record *rr;
2267 dns_address **addrp = &(cb->rhs);
2268 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2269 rr != NULL;
2270 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
2271 {
2272 if (rr->type == T_A)
2273 {
2274 dns_address *da = dns_address_from_rr(&dnsa, rr);
2275 if (da != NULL)
2276 {
2277 *addrp = da;
2278 while (da->next != NULL) da = da->next;
2279 addrp = &(da->next);
2280 }
2281 }
2282 }
2283
2284 /* If we didn't find any A records, change the return code. This can
2285 happen when there is a CNAME record but there are no A records for what
2286 it points to. */
2287
2288 if (cb->rhs == NULL) cb->rc = DNS_NODATA;
2289 }
2290
2291 store_pool = old_pool;
2292 }
2293
2294/* Previous lookup was cached */
2295
2296else
2297 {
2298 HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
2299 cb = t->data.ptr;
2300 }
2301
2302/* We now have the result of the DNS lookup, either newly done, or cached
2303from a previous call. If the lookup succeeded, check against the address
2304list if there is one. This may be a positive equality list (introduced by
2305"="), a negative equality list (introduced by "!="), a positive bitmask
2306list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/
2307
2308if (cb->rc == DNS_SUCCEED)
2309 {
2310 dns_address *da = NULL;
2311 uschar *addlist = cb->rhs->address;
2312
2313 /* For A and AAAA records, there may be multiple addresses from multiple
2314 records. For A6 records (currently not expected to be used) there may be
2315 multiple addresses from a single record. */
2316
2317 for (da = cb->rhs->next; da != NULL; da = da->next)
2318 addlist = string_sprintf("%s, %s", addlist, da->address);
2319
2320 HDEBUG(D_dnsbl) debug_printf("DNS lookup for %s succeeded (yielding %s)\n",
2321 query, addlist);
2322
2323 /* Address list check; this can be either for equality, or via a bitmask.
2324 In the latter case, all the bits must match. */
2325
2326 if (iplist != NULL)
2327 {
2328 int ipsep = ',';
2329 uschar ip[46];
2330 uschar *ptr = iplist;
2331
2332 while (string_nextinlist(&ptr, &ipsep, ip, sizeof(ip)) != NULL)
2333 {
2334 /* Handle exact matching */
2335 if (!bitmask)
2336 {
2337 for (da = cb->rhs; da != NULL; da = da->next)
2338 {
2339 if (Ustrcmp(CS da->address, ip) == 0) break;
2340 }
2341 }
2342 /* Handle bitmask matching */
2343 else
2344 {
2345 int address[4];
2346 int mask = 0;
2347
2348 /* At present, all known DNS blocking lists use A records, with
2349 IPv4 addresses on the RHS encoding the information they return. I
2350 wonder if this will linger on as the last vestige of IPv4 when IPv6
2351 is ubiquitous? Anyway, for now we use paranoia code to completely
2352 ignore IPv6 addresses. The default mask is 0, which always matches.
2353 We change this only for IPv4 addresses in the list. */
2354
2355 if (host_aton(ip, address) == 1) mask = address[0];
2356
2357 /* Scan the returned addresses, skipping any that are IPv6 */
2358
2359 for (da = cb->rhs; da != NULL; da = da->next)
2360 {
2361 if (host_aton(da->address, address) != 1) continue;
2362 if ((address[0] & mask) == mask) break;
2363 }
2364 }
2365
2366 /* Break out if a match has been found */
2367
2368 if (da != NULL) break;
2369 }
2370
2371 /* If either
2372
2373 (a) No IP address in a positive list matched, or
2374 (b) An IP address in a negative list did match
2375
2376 then behave as if the DNSBL lookup had not succeeded, i.e. the host is
2377 not on the list. */
2378
2379 if (invert_result != (da == NULL))
2380 {
2381 HDEBUG(D_dnsbl)
2382 {
2383 debug_printf("=> but we are not accepting this block class because\n");
2384 debug_printf("=> there was %s match for %c%s\n",
2385 invert_result? "an exclude":"no", bitmask? '&' : '=', iplist);
2386 }
8e669ac1 2387 return FAIL;
0bcb2a0e
PH
2388 }
2389 }
2390
2391 /* Either there was no IP list, or the record matched. Look up a TXT record
2392 if it hasn't previously been done. */
2393
2394 if (!cb->text_set)
2395 {
2396 cb->text_set = TRUE;
2397 if (dns_basic_lookup(&dnsa, query, T_TXT) == DNS_SUCCEED)
2398 {
2399 dns_record *rr;
2400 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2401 rr != NULL;
2402 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
2403 if (rr->type == T_TXT) break;
2404 if (rr != NULL)
2405 {
2406 int len = (rr->data)[0];
2407 if (len > 511) len = 127;
2408 store_pool = POOL_PERM;
2409 cb->text = string_sprintf("%.*s", len, (const uschar *)(rr->data+1));
2410 store_pool = old_pool;
2411 }
2412 }
2413 }
2414
2415 dnslist_value = addlist;
2416 dnslist_text = cb->text;
2417 return OK;
2418 }
2419
2420/* There was a problem with the DNS lookup */
2421
2422if (cb->rc != DNS_NOMATCH && cb->rc != DNS_NODATA)
2423 {
2424 log_write(L_dnslist_defer, LOG_MAIN,
2425 "DNS list lookup defer (probably timeout) for %s: %s", query,
2426 (defer_return == OK)? US"assumed in list" :
2427 (defer_return == FAIL)? US"assumed not in list" :
2428 US"returned DEFER");
2429 return defer_return;
2430 }
2431
2432/* No entry was found in the DNS; continue for next domain */
2433
2434HDEBUG(D_dnsbl)
2435 {
2436 debug_printf("DNS lookup for %s failed\n", query);
2437 debug_printf("=> that means %s is not listed at %s\n",
2438 keydomain, domain);
2439 }
2440
2441return FAIL;
2442}
2443
2444
2445
2446
2447/*************************************************
059ec3d9
PH
2448* Check host against DNS black lists *
2449*************************************************/
2450
2451/* This function runs checks against a list of DNS black lists, until one
2452matches. Each item on the list can be of the form
2453
2454 domain=ip-address/key
2455
2456The domain is the right-most domain that is used for the query, for example,
2457blackholes.mail-abuse.org. If the IP address is present, there is a match only
2458if the DNS lookup returns a matching IP address. Several addresses may be
2459given, comma-separated, for example: x.y.z=127.0.0.1,127.0.0.2.
2460
2461If no key is given, what is looked up in the domain is the inverted IP address
2462of the current client host. If a key is given, it is used to construct the
2463domain for the lookup. For example,
2464
2465 dsn.rfc-ignorant.org/$sender_address_domain
2466
2467After finding a match in the DNS, the domain is placed in $dnslist_domain, and
2468then we check for a TXT record for an error message, and if found, save its
2469value in $dnslist_text. We also cache everything in a tree, to optimize
2470multiple lookups.
2471
2472Note: an address for testing RBL is 192.203.178.39
2473Note: an address for testing DUL is 192.203.178.4
2474Note: a domain for testing RFCI is example.tld.dsn.rfc-ignorant.org
2475
2476Arguments:
2477 listptr the domain/address/data list
2478
2479Returns: OK successful lookup (i.e. the address is on the list), or
2480 lookup deferred after +include_unknown
2481 FAIL name not found, or no data found for the given type, or
2482 lookup deferred after +exclude_unknown (default)
2483 DEFER lookup failure, if +defer_unknown was set
2484*/
2485
2486int
2487verify_check_dnsbl(uschar **listptr)
2488{
2489int sep = 0;
2490int defer_return = FAIL;
059ec3d9
PH
2491BOOL invert_result = FALSE;
2492uschar *list = *listptr;
2493uschar *domain;
2494uschar *s;
2495uschar buffer[1024];
2496uschar query[256]; /* DNS domain max length */
2497uschar revadd[128]; /* Long enough for IPv6 address */
2498
2499/* Indicate that the inverted IP address is not yet set up */
2500
2501revadd[0] = 0;
2502
0bcb2a0e
PH
2503/* In case this is the first time the DNS resolver is being used. */
2504
2505dns_init(FALSE, FALSE);
2506
059ec3d9
PH
2507/* Loop through all the domains supplied, until something matches */
2508
2509while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
2510 {
0bcb2a0e 2511 int rc;
059ec3d9
PH
2512 BOOL frc;
2513 BOOL bitmask = FALSE;
059ec3d9
PH
2514 uschar *iplist;
2515 uschar *key;
059ec3d9
PH
2516
2517 HDEBUG(D_dnsbl) debug_printf("DNS list check: %s\n", domain);
2518
2519 /* Deal with special values that change the behaviour on defer */
2520
2521 if (domain[0] == '+')
2522 {
2523 if (strcmpic(domain, US"+include_unknown") == 0) defer_return = OK;
2524 else if (strcmpic(domain, US"+exclude_unknown") == 0) defer_return = FAIL;
2525 else if (strcmpic(domain, US"+defer_unknown") == 0) defer_return = DEFER;
2526 else
2527 log_write(0, LOG_MAIN|LOG_PANIC, "unknown item in dnslist (ignored): %s",
2528 domain);
2529 continue;
2530 }
2531
2532 /* See if there's explicit data to be looked up */
2533
2534 key = Ustrchr(domain, '/');
2535 if (key != NULL) *key++ = 0;
2536
2537 /* See if there's a list of addresses supplied after the domain name. This is
2538 introduced by an = or a & character; if preceded by ! we invert the result.
2539 */
2540
2541 iplist = Ustrchr(domain, '=');
2542 if (iplist == NULL)
2543 {
2544 bitmask = TRUE;
2545 iplist = Ustrchr(domain, '&');
2546 }
2547
2548 if (iplist != NULL)
2549 {
2550 if (iplist > domain && iplist[-1] == '!')
2551 {
2552 invert_result = TRUE;
2553 iplist[-1] = 0;
2554 }
2555 *iplist++ = 0;
2556 }
2557
2558 /* Check that what we have left is a sensible domain name. There is no reason
2559 why these domains should in fact use the same syntax as hosts and email
2560 domains, but in practice they seem to. However, there is little point in
2561 actually causing an error here, because that would no doubt hold up incoming
2562 mail. Instead, I'll just log it. */
2563
2564 for (s = domain; *s != 0; s++)
2565 {
2566 if (!isalnum(*s) && *s != '-' && *s != '.')
2567 {
2568 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
2569 "strange characters - is this right?", domain);
2570 break;
2571 }
2572 }
2573
8e669ac1 2574 /* If there is no key string, construct the query by adding the domain name
0bcb2a0e 2575 onto the inverted host address, and perform a single DNS lookup. */
8e669ac1 2576
059ec3d9
PH
2577 if (key == NULL)
2578 {
2579 if (sender_host_address == NULL) return FAIL; /* can never match */
2580 if (revadd[0] == 0) invert_address(revadd, sender_host_address);
2581 frc = string_format(query, sizeof(query), "%s%s", revadd, domain);
8e669ac1 2582
0bcb2a0e 2583 if (!frc)
059ec3d9 2584 {
0bcb2a0e
PH
2585 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
2586 "(ignored): %s...", query);
2587 continue;
059ec3d9 2588 }
8e669ac1
PH
2589
2590 rc = one_check_dnsbl(domain, sender_host_address, query, iplist, bitmask,
0bcb2a0e 2591 invert_result, defer_return);
8e669ac1 2592
0bcb2a0e
PH
2593 if (rc == OK)
2594 {
2595 dnslist_domain = string_copy(domain);
8e669ac1 2596 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
0bcb2a0e
PH
2597 sender_host_address, domain);
2598 }
8e669ac1 2599
0bcb2a0e 2600 if (rc != FAIL) return rc; /* OK or DEFER */
059ec3d9 2601 }
8e669ac1
PH
2602
2603 /* If there is a key string, it can be a list of domains or IP addresses to
0bcb2a0e 2604 be concatenated with the main domain. */
8e669ac1 2605
059ec3d9
PH
2606 else
2607 {
0bcb2a0e 2608 int keysep = 0;
8e669ac1
PH
2609 BOOL defer = FALSE;
2610 uschar *keydomain;
0bcb2a0e 2611 uschar keybuffer[256];
8e669ac1
PH
2612
2613 while ((keydomain = string_nextinlist(&key, &keysep, keybuffer,
0bcb2a0e 2614 sizeof(keybuffer))) != NULL)
8e669ac1 2615 {
a5a28604 2616 if (string_is_ip_address(keydomain, NULL) > 0)
059ec3d9 2617 {
0bcb2a0e
PH
2618 uschar keyrevadd[128];
2619 invert_address(keyrevadd, keydomain);
8e669ac1 2620 frc = string_format(query, sizeof(query), "%s%s", keyrevadd, domain);
0bcb2a0e
PH
2621 }
2622 else
8e669ac1 2623 {
0bcb2a0e 2624 frc = string_format(query, sizeof(query), "%s.%s", keydomain, domain);
059ec3d9
PH
2625 }
2626
0bcb2a0e 2627 if (!frc)
059ec3d9 2628 {
0bcb2a0e
PH
2629 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
2630 "(ignored): %s...", query);
2631 continue;
059ec3d9 2632 }
8e669ac1
PH
2633
2634 rc = one_check_dnsbl(domain, keydomain, query, iplist, bitmask,
0bcb2a0e 2635 invert_result, defer_return);
8e669ac1 2636
0bcb2a0e 2637 if (rc == OK)
059ec3d9 2638 {
0bcb2a0e 2639 dnslist_domain = string_copy(domain);
8e669ac1 2640 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
0bcb2a0e 2641 keydomain, domain);
8e669ac1 2642 return OK;
059ec3d9 2643 }
8e669ac1 2644
c38d6da9
PH
2645 /* If the lookup deferred, remember this fact. We keep trying the rest
2646 of the list to see if we get a useful result, and if we don't, we return
2647 DEFER at the end. */
059ec3d9 2648
c38d6da9 2649 if (rc == DEFER) defer = TRUE;
0bcb2a0e 2650 } /* continue with next keystring domain/address */
c38d6da9
PH
2651
2652 if (defer) return DEFER;
8e669ac1 2653 }
0bcb2a0e 2654 } /* continue with next dnsdb outer domain */
059ec3d9
PH
2655
2656return FAIL;
2657}
2658
2659/* End of verify.c */