1 /* $Cambridge: exim/src/src/verify.c,v 1.42 2006/10/09 14:36:25 ph10 Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2006 */
8 /* See the file NOTICE for conditions of use and distribution. */
10 /* Functions concerned with verifying things. The original code for callout
11 caching was contributed by Kevin Fleming (but I hacked it around a bit). */
17 /* Structure for caching DNSBL lookups */
19 typedef struct dnsbl_cache_block {
27 /* Anchor for DNSBL cache */
29 static tree_node *dnsbl_cache = NULL;
33 /*************************************************
34 * Retrieve a callout cache record *
35 *************************************************/
37 /* If a record exists, check whether it has expired.
40 dbm_file an open hints file
42 type "address" or "domain"
43 positive_expire expire time for positive records
44 negative_expire expire time for negative records
46 Returns: the cache record if a non-expired one exists, else NULL
49 static dbdata_callout_cache *
50 get_callout_cache_record(open_db *dbm_file, uschar *key, uschar *type,
51 int positive_expire, int negative_expire)
56 dbdata_callout_cache *cache_record;
58 cache_record = dbfn_read_with_length(dbm_file, key, &length);
60 if (cache_record == NULL)
62 HDEBUG(D_verify) debug_printf("callout cache: no %s record found\n", type);
66 /* We treat a record as "negative" if its result field is not positive, or if
67 it is a domain record and the postmaster field is negative. */
69 negative = cache_record->result != ccache_accept ||
70 (type[0] == 'd' && cache_record->postmaster_result == ccache_reject);
71 expire = negative? negative_expire : positive_expire;
74 if (now - cache_record->time_stamp > expire)
76 HDEBUG(D_verify) debug_printf("callout cache: %s record expired\n", type);
80 /* If this is a non-reject domain record, check for the obsolete format version
81 that doesn't have the postmaster and random timestamps, by looking at the
82 length. If so, copy it to a new-style block, replicating the record's
83 timestamp. Then check the additional timestamps. (There's no point wasting
84 effort if connections are rejected.) */
86 if (type[0] == 'd' && cache_record->result != ccache_reject)
88 if (length == sizeof(dbdata_callout_cache_obs))
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;
96 if (now - cache_record->postmaster_stamp > expire)
97 cache_record->postmaster_result = ccache_unknown;
99 if (now - cache_record->random_stamp > expire)
100 cache_record->random_result = ccache_unknown;
103 HDEBUG(D_verify) debug_printf("callout cache: found %s record\n", type);
109 /*************************************************
110 * Do callout verification for an address *
111 *************************************************/
113 /* This function is called from verify_address() when the address has routed to
114 a host list, and a callout has been requested. Callouts are expensive; that is
115 why a cache is used to improve the efficiency.
118 addr the address that's been routed
119 host_list the list of hosts to try
120 tf the transport feedback block
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
126 callout_overall the overall callout timeout (if < 0 use 4*callout)
127 callout_connect the callout connection timeout (if < 0 use callout)
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_fullpm => if postmaster check, do full one
132 vopt_callout_random => do the "random" thing
133 vopt_callout_recipsender => use real sender for recipient
134 vopt_callout_recippmaster => use postmaster for recipient
135 se_mailfrom MAIL FROM address for sender verify; NULL => ""
136 pm_mailfrom if non-NULL, do the postmaster check with this sender
138 Returns: OK/FAIL/DEFER
142 do_callout(address_item *addr, host_item *host_list, transport_feedback *tf,
143 int callout, int callout_overall, int callout_connect, int options,
144 uschar *se_mailfrom, uschar *pm_mailfrom)
146 BOOL is_recipient = (options & vopt_is_recipient) != 0;
147 BOOL callout_no_cache = (options & vopt_callout_no_cache) != 0;
148 BOOL callout_random = (options & vopt_callout_random) != 0;
151 int old_domain_cache_result = ccache_accept;
154 uschar *from_address;
155 uschar *random_local_part = NULL;
156 uschar *save_deliver_domain = deliver_domain;
157 uschar **failure_ptr = is_recipient?
158 &recipient_verify_failure : &sender_verify_failure;
160 open_db *dbm_file = NULL;
161 dbdata_callout_cache new_domain_record;
162 dbdata_callout_cache_address new_address_record;
164 time_t callout_start_time;
166 new_domain_record.result = ccache_unknown;
167 new_domain_record.postmaster_result = ccache_unknown;
168 new_domain_record.random_result = ccache_unknown;
170 memset(&new_address_record, 0, sizeof(new_address_record));
172 /* For a recipient callout, the key used for the address cache record must
173 include the sender address if we are using the real sender in the callout,
174 because that may influence the result of the callout. */
176 address_key = addr->address;
181 if ((options & vopt_callout_recipsender) != 0)
183 address_key = string_sprintf("%s/<%s>", addr->address, sender_address);
184 from_address = sender_address;
186 else if ((options & vopt_callout_recippmaster) != 0)
188 address_key = string_sprintf("%s/<postmaster@%s>", addr->address,
189 qualify_domain_sender);
190 from_address = string_sprintf("postmaster@%s", qualify_domain_sender);
194 /* For a sender callout, we must adjust the key if the mailfrom address is not
199 from_address = (se_mailfrom == NULL)? US"" : se_mailfrom;
200 if (from_address[0] != 0)
201 address_key = string_sprintf("%s/<%s>", addr->address, from_address);
204 /* Open the callout cache database, it it exists, for reading only at this
205 stage, unless caching has been disabled. */
207 if (callout_no_cache)
209 HDEBUG(D_verify) debug_printf("callout cache: disabled by no_cache\n");
211 else if ((dbm_file = dbfn_open(US"callout", O_RDWR, &dbblock, FALSE)) == NULL)
213 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
216 /* If a cache database is available see if we can avoid the need to do an
217 actual callout by making use of previously-obtained data. */
219 if (dbm_file != NULL)
221 dbdata_callout_cache_address *cache_address_record;
222 dbdata_callout_cache *cache_record = get_callout_cache_record(dbm_file,
223 addr->domain, US"domain",
224 callout_cache_domain_positive_expire,
225 callout_cache_domain_negative_expire);
227 /* If an unexpired cache record was found for this domain, see if the callout
228 process can be short-circuited. */
230 if (cache_record != NULL)
232 /* In most cases, if an early command (up to and including MAIL FROM:<>)
233 was rejected, there is no point carrying on. The callout fails. However, if
234 we are doing a recipient verification with use_sender or use_postmaster
235 set, a previous failure of MAIL FROM:<> doesn't count, because this time we
236 will be using a non-empty sender. We have to remember this situation so as
237 not to disturb the cached domain value if this whole verification succeeds
238 (we don't want it turning into "accept"). */
240 old_domain_cache_result = cache_record->result;
242 if (cache_record->result == ccache_reject ||
243 (*from_address == 0 && cache_record->result == ccache_reject_mfnull))
245 setflag(addr, af_verify_nsfail);
247 debug_printf("callout cache: domain gave initial rejection, or "
248 "does not accept HELO or MAIL FROM:<>\n");
249 setflag(addr, af_verify_nsfail);
250 addr->user_message = US"(result of an earlier callout reused).";
252 *failure_ptr = US"mail";
256 /* If a previous check on a "random" local part was accepted, we assume
257 that the server does not do any checking on local parts. There is therefore
258 no point in doing the callout, because it will always be successful. If a
259 random check previously failed, arrange not to do it again, but preserve
260 the data in the new record. If a random check is required but hasn't been
261 done, skip the remaining cache processing. */
263 if (callout_random) switch(cache_record->random_result)
267 debug_printf("callout cache: domain accepts random addresses\n");
268 goto END_CALLOUT; /* Default yield is OK */
272 debug_printf("callout cache: domain rejects random addresses\n");
273 callout_random = FALSE;
274 new_domain_record.random_result = ccache_reject;
275 new_domain_record.random_stamp = cache_record->random_stamp;
280 debug_printf("callout cache: need to check random address handling "
281 "(not cached or cache expired)\n");
285 /* If a postmaster check is requested, but there was a previous failure,
286 there is again no point in carrying on. If a postmaster check is required,
287 but has not been done before, we are going to have to do a callout, so skip
288 remaining cache processing. */
290 if (pm_mailfrom != NULL)
292 if (cache_record->postmaster_result == ccache_reject)
294 setflag(addr, af_verify_pmfail);
296 debug_printf("callout cache: domain does not accept "
297 "RCPT TO:<postmaster@domain>\n");
299 *failure_ptr = US"postmaster";
300 setflag(addr, af_verify_pmfail);
301 addr->user_message = US"(result of earlier verification reused).";
304 if (cache_record->postmaster_result == ccache_unknown)
307 debug_printf("callout cache: need to check RCPT "
308 "TO:<postmaster@domain> (not cached or cache expired)\n");
312 /* If cache says OK, set pm_mailfrom NULL to prevent a redundant
313 postmaster check if the address itself has to be checked. Also ensure
314 that the value in the cache record is preserved (with its old timestamp).
317 HDEBUG(D_verify) debug_printf("callout cache: domain accepts RCPT "
318 "TO:<postmaster@domain>\n");
320 new_domain_record.postmaster_result = ccache_accept;
321 new_domain_record.postmaster_stamp = cache_record->postmaster_stamp;
325 /* We can't give a result based on information about the domain. See if there
326 is an unexpired cache record for this specific address (combined with the
327 sender address if we are doing a recipient callout with a non-empty sender).
330 cache_address_record = (dbdata_callout_cache_address *)
331 get_callout_cache_record(dbm_file,
332 address_key, US"address",
333 callout_cache_positive_expire,
334 callout_cache_negative_expire);
336 if (cache_address_record != NULL)
338 if (cache_address_record->result == ccache_accept)
341 debug_printf("callout cache: address record is positive\n");
346 debug_printf("callout cache: address record is negative\n");
347 addr->user_message = US"Previous (cached) callout verification failure";
348 *failure_ptr = US"recipient";
354 /* Close the cache database while we actually do the callout for real. */
357 dbfn_close(dbm_file);
361 /* The information wasn't available in the cache, so we have to do a real
362 callout and save the result in the cache for next time, unless no_cache is set,
363 or unless we have a previously cached negative random result. If we are to test
364 with a random local part, ensure that such a local part is available. If not,
365 log the fact, but carry on without randomming. */
367 if (callout_random && callout_random_local_part != NULL)
369 random_local_part = expand_string(callout_random_local_part);
370 if (random_local_part == NULL)
371 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand "
372 "callout_random_local_part: %s", expand_string_message);
375 /* Default the connect and overall callout timeouts if not set, and record the
376 time we are starting so that we can enforce it. */
378 if (callout_overall < 0) callout_overall = 4 * callout;
379 if (callout_connect < 0) callout_connect = callout;
380 callout_start_time = time(NULL);
382 /* Now make connections to the hosts and do real callouts. The list of hosts
383 is passed in as an argument. */
385 for (host = host_list; host != NULL && !done; host = host->next)
387 smtp_inblock inblock;
388 smtp_outblock outblock;
391 BOOL send_quit = TRUE;
392 uschar *active_hostname = smtp_active_hostname;
393 uschar *helo = US"HELO";
394 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
395 uschar inbuffer[4096];
396 uschar outbuffer[1024];
397 uschar responsebuffer[4096];
399 clearflag(addr, af_verify_pmfail); /* postmaster callout flag */
400 clearflag(addr, af_verify_nsfail); /* null sender callout flag */
402 /* Skip this host if we don't have an IP address for it. */
404 if (host->address == NULL)
406 DEBUG(D_verify) debug_printf("no IP address for host name %s: skipping\n",
411 /* Check the overall callout timeout */
413 if (time(NULL) - callout_start_time >= callout_overall)
415 HDEBUG(D_verify) debug_printf("overall timeout for callout exceeded\n");
419 /* Set IPv4 or IPv6 */
421 host_af = (Ustrchr(host->address, ':') == NULL)? AF_INET:AF_INET6;
423 /* Expand and interpret the interface and port strings. The latter will not
424 be used if there is a host-specific port (e.g. from a manualroute router).
425 This has to be delayed till now, because they may expand differently for
426 different hosts. If there's a failure, log it, but carry on with the
429 deliver_host = host->name;
430 deliver_host_address = host->address;
431 deliver_domain = addr->domain;
433 if (!smtp_get_interface(tf->interface, host_af, addr, NULL, &interface,
435 !smtp_get_port(tf->port, addr, &port, US"callout"))
436 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
439 /* Expand the helo_data string to find the host name to use. */
441 if (tf->helo_data != NULL)
443 uschar *s = expand_string(tf->helo_data);
444 if (active_hostname == NULL)
445 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: failed to expand transport's "
446 "helo_data value for callout: %s", expand_string_message);
447 else active_hostname = s;
450 deliver_host = deliver_host_address = NULL;
451 deliver_domain = save_deliver_domain;
453 /* Set HELO string according to the protocol */
455 if (Ustrcmp(tf->protocol, "lmtp") == 0) helo = US"LHLO";
457 HDEBUG(D_verify) debug_printf("interface=%s port=%d\n", interface, port);
459 /* Set up the buffer for reading SMTP response packets. */
461 inblock.buffer = inbuffer;
462 inblock.buffersize = sizeof(inbuffer);
463 inblock.ptr = inbuffer;
464 inblock.ptrend = inbuffer;
466 /* Set up the buffer for holding SMTP commands while pipelining */
468 outblock.buffer = outbuffer;
469 outblock.buffersize = sizeof(outbuffer);
470 outblock.ptr = outbuffer;
471 outblock.cmd_count = 0;
472 outblock.authenticating = FALSE;
474 /* Connect to the host; on failure, just loop for the next one, but we
475 set the error for the last one. Use the callout_connect timeout. */
477 inblock.sock = outblock.sock =
478 smtp_connect(host, host_af, port, interface, callout_connect, TRUE);
479 if (inblock.sock < 0)
481 addr->message = string_sprintf("could not connect to %s [%s]: %s",
482 host->name, host->address, strerror(errno));
486 /* Wait for initial response, and send HELO. The smtp_write_command()
487 function leaves its command in big_buffer. This is used in error responses.
488 Initialize it in case the connection is rejected. */
490 Ustrcpy(big_buffer, "initial connection");
493 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
495 smtp_write_command(&outblock, FALSE, "%s %s\r\n", helo,
496 active_hostname) >= 0 &&
497 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
500 /* Failure to accept HELO is cached; this blocks the whole domain for all
501 senders. I/O errors and defer responses are not cached. */
505 *failure_ptr = US"mail"; /* At or before MAIL */
506 if (errno == 0 && responsebuffer[0] == '5')
508 setflag(addr, af_verify_nsfail);
509 new_domain_record.result = ccache_reject;
513 /* Send the MAIL command */
516 smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>\r\n",
517 from_address) >= 0 &&
518 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
521 /* If the host does not accept MAIL FROM:<>, arrange to cache this
522 information, but again, don't record anything for an I/O error or a defer. Do
523 not cache rejections of MAIL when a non-empty sender has been used, because
524 that blocks the whole domain for all senders. */
528 *failure_ptr = US"mail"; /* At or before MAIL */
529 if (errno == 0 && responsebuffer[0] == '5')
531 setflag(addr, af_verify_nsfail);
532 if (from_address[0] == 0)
533 new_domain_record.result = ccache_reject_mfnull;
537 /* Otherwise, proceed to check a "random" address (if required), then the
538 given address, and the postmaster address (if required). Between each check,
539 issue RSET, because some servers accept only one recipient after MAIL
542 Before doing this, set the result in the domain cache record to "accept",
543 unless its previous value was ccache_reject_mfnull. In that case, the domain
544 rejects MAIL FROM:<> and we want to continue to remember that. When that is
545 the case, we have got here only in the case of a recipient verification with
546 a non-null sender. */
550 new_domain_record.result =
551 (old_domain_cache_result == ccache_reject_mfnull)?
552 ccache_reject_mfnull: ccache_accept;
554 /* Do the random local part check first */
556 if (random_local_part != NULL)
558 uschar randombuffer[1024];
560 smtp_write_command(&outblock, FALSE,
561 "RCPT TO:<%.1000s@%.1000s>\r\n", random_local_part,
562 addr->domain) >= 0 &&
563 smtp_read_response(&inblock, randombuffer,
564 sizeof(randombuffer), '2', callout);
566 /* Remember when we last did a random test */
568 new_domain_record.random_stamp = time(NULL);
570 /* If accepted, we aren't going to do any further tests below. */
574 new_domain_record.random_result = ccache_accept;
577 /* Otherwise, cache a real negative response, and get back to the right
578 state to send RCPT. Unless there's some problem such as a dropped
579 connection, we expect to succeed, because the commands succeeded above. */
583 if (randombuffer[0] == '5')
584 new_domain_record.random_result = ccache_reject;
587 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
588 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
591 smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>\r\n",
592 from_address) >= 0 &&
593 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
596 else done = FALSE; /* Some timeout/connection problem */
599 /* If the host is accepting all local parts, as determined by the "random"
600 check, we don't need to waste time doing any further checking. */
602 if (new_domain_record.random_result != ccache_accept && done)
604 /* Get the rcpt_include_affixes flag from the transport if there is one,
605 but assume FALSE if there is not. */
608 smtp_write_command(&outblock, FALSE, "RCPT TO:<%.1000s>\r\n",
609 transport_rcpt_address(addr,
610 (addr->transport == NULL)? FALSE :
611 addr->transport->rcpt_include_affixes)) >= 0 &&
612 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
616 new_address_record.result = ccache_accept;
617 else if (errno == 0 && responsebuffer[0] == '5')
619 *failure_ptr = US"recipient";
620 new_address_record.result = ccache_reject;
623 /* Do postmaster check if requested; if a full check is required, we
624 check for RCPT TO:<postmaster> (no domain) in accordance with RFC 821. */
626 if (done && pm_mailfrom != NULL)
629 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
630 smtp_read_response(&inblock, responsebuffer,
631 sizeof(responsebuffer), '2', callout) &&
633 smtp_write_command(&outblock, FALSE,
634 "MAIL FROM:<%s>\r\n", pm_mailfrom) >= 0 &&
635 smtp_read_response(&inblock, responsebuffer,
636 sizeof(responsebuffer), '2', callout) &&
638 /* First try using the current domain */
641 smtp_write_command(&outblock, FALSE,
642 "RCPT TO:<postmaster@%.1000s>\r\n", addr->domain) >= 0 &&
643 smtp_read_response(&inblock, responsebuffer,
644 sizeof(responsebuffer), '2', callout)
649 /* If that doesn't work, and a full check is requested,
650 try without the domain. */
653 (options & vopt_callout_fullpm) != 0 &&
654 smtp_write_command(&outblock, FALSE,
655 "RCPT TO:<postmaster>\r\n") >= 0 &&
656 smtp_read_response(&inblock, responsebuffer,
657 sizeof(responsebuffer), '2', callout)
660 /* Sort out the cache record */
662 new_domain_record.postmaster_stamp = time(NULL);
665 new_domain_record.postmaster_result = ccache_accept;
666 else if (errno == 0 && responsebuffer[0] == '5')
668 *failure_ptr = US"postmaster";
669 setflag(addr, af_verify_pmfail);
670 new_domain_record.postmaster_result = ccache_reject;
673 } /* Random not accepted */
674 } /* MAIL FROM: accepted */
676 /* For any failure of the main check, other than a negative response, we just
677 close the connection and carry on. We can identify a negative response by the
678 fact that errno is zero. For I/O errors it will be non-zero
680 Set up different error texts for logging and for sending back to the caller
681 as an SMTP response. Log in all cases, using a one-line format. For sender
682 callouts, give a full response to the caller, but for recipient callouts,
683 don't give the IP address because this may be an internal host whose identity
684 is not to be widely broadcast. */
688 if (errno == ETIMEDOUT)
690 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
695 if (*responsebuffer == 0) Ustrcpy(responsebuffer, US"connection dropped");
698 string_sprintf("response to \"%s\" from %s [%s] was: %s",
699 big_buffer, host->name, host->address,
700 string_printing(responsebuffer));
702 addr->user_message = is_recipient?
703 string_sprintf("Callout verification failed:\n%s", responsebuffer)
705 string_sprintf("Called: %s\nSent: %s\nResponse: %s",
706 host->address, big_buffer, responsebuffer);
708 /* Hard rejection ends the process */
710 if (responsebuffer[0] == '5') /* Address rejected */
718 /* End the SMTP conversation and close the connection. */
720 if (send_quit) (void)smtp_write_command(&outblock, FALSE, "QUIT\r\n");
721 (void)close(inblock.sock);
722 } /* Loop through all hosts, while !done */
724 /* If we get here with done == TRUE, a successful callout happened, and yield
725 will be set OK or FAIL according to the response to the RCPT command.
726 Otherwise, we looped through the hosts but couldn't complete the business.
727 However, there may be domain-specific information to cache in both cases.
729 The value of the result field in the new_domain record is ccache_unknown if
730 there was an error before or with MAIL FROM:, and errno was not zero,
731 implying some kind of I/O error. We don't want to write the cache in that case.
732 Otherwise the value is ccache_accept, ccache_reject, or ccache_reject_mfnull. */
734 if (!callout_no_cache && new_domain_record.result != ccache_unknown)
736 if ((dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE))
739 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
743 (void)dbfn_write(dbm_file, addr->domain, &new_domain_record,
744 (int)sizeof(dbdata_callout_cache));
745 HDEBUG(D_verify) debug_printf("wrote callout cache domain record:\n"
746 " result=%d postmaster=%d random=%d\n",
747 new_domain_record.result,
748 new_domain_record.postmaster_result,
749 new_domain_record.random_result);
753 /* If a definite result was obtained for the callout, cache it unless caching
758 if (!callout_no_cache && new_address_record.result != ccache_unknown)
760 if (dbm_file == NULL)
761 dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE);
762 if (dbm_file == NULL)
764 HDEBUG(D_verify) debug_printf("no callout cache available\n");
768 (void)dbfn_write(dbm_file, address_key, &new_address_record,
769 (int)sizeof(dbdata_callout_cache_address));
770 HDEBUG(D_verify) debug_printf("wrote %s callout cache address record\n",
771 (new_address_record.result == ccache_accept)? "positive" : "negative");
776 /* Failure to connect to any host, or any response other than 2xx or 5xx is a
777 temporary error. If there was only one host, and a response was received, leave
778 it alone if supplying details. Otherwise, give a generic response. */
782 uschar *dullmsg = string_sprintf("Could not complete %s verify callout",
783 is_recipient? "recipient" : "sender");
786 if (host_list->next != NULL || addr->message == NULL) addr->message = dullmsg;
788 addr->user_message = (!smtp_return_error_details)? dullmsg :
789 string_sprintf("%s for <%s>.\n"
790 "The mail server(s) for the domain may be temporarily unreachable, or\n"
791 "they may be permanently unreachable from this server. In the latter case,\n%s",
792 dullmsg, addr->address,
794 "the address will never be accepted."
796 "you need to change the address or create an MX record for its domain\n"
797 "if it is supposed to be generally accessible from the Internet.\n"
798 "Talk to your mail administrator for details.");
800 /* Force a specific error code */
802 addr->basic_errno = ERRNO_CALLOUTDEFER;
805 /* Come here from within the cache-reading code on fast-track exit. */
808 if (dbm_file != NULL) dbfn_close(dbm_file);
814 /*************************************************
815 * Copy error to toplevel address *
816 *************************************************/
818 /* This function is used when a verify fails or defers, to ensure that the
819 failure or defer information is in the original toplevel address. This applies
820 when an address is redirected to a single new address, and the failure or
821 deferral happens to the child address.
824 vaddr the verify address item
825 addr the final address item
828 Returns: the value of YIELD
832 copy_error(address_item *vaddr, address_item *addr, int yield)
836 vaddr->message = addr->message;
837 vaddr->user_message = addr->user_message;
838 vaddr->basic_errno = addr->basic_errno;
839 vaddr->more_errno = addr->more_errno;
840 vaddr->p.address_data = addr->p.address_data;
848 /*************************************************
849 * Verify an email address *
850 *************************************************/
852 /* This function is used both for verification (-bv and at other times) and
853 address testing (-bt), which is indicated by address_test_mode being set.
856 vaddr contains the address to verify; the next field in this block
858 f if not NULL, write the result to this file
859 options various option bits:
860 vopt_fake_sender => this sender verify is not for the real
861 sender (it was verify=sender=xxxx or an address from a
862 header line) - rewriting must not change sender_address
863 vopt_is_recipient => this is a recipient address, otherwise
864 it's a sender address - this affects qualification and
865 rewriting and messages from callouts
866 vopt_qualify => qualify an unqualified address; else error
867 vopt_expn => called from SMTP EXPN command
868 vopt_success_on_redirect => when a new address is generated
869 the verification instantly succeeds
871 These ones are used by do_callout() -- the options variable
874 vopt_callout_fullpm => if postmaster check, do full one
875 vopt_callout_no_cache => don't use callout cache
876 vopt_callout_random => do the "random" thing
877 vopt_callout_recipsender => use real sender for recipient
878 vopt_callout_recippmaster => use postmaster for recipient
880 callout if > 0, specifies that callout is required, and gives timeout
881 for individual commands
882 callout_overall if > 0, gives overall timeout for the callout function;
883 if < 0, a default is used (see do_callout())
884 callout_connect the connection timeout for callouts
885 se_mailfrom when callout is requested to verify a sender, use this
886 in MAIL FROM; NULL => ""
887 pm_mailfrom when callout is requested, if non-NULL, do the postmaster
888 thing and use this as the sender address (may be "")
890 routed if not NULL, set TRUE if routing succeeded, so we can
891 distinguish between routing failed and callout failed
893 Returns: OK address verified
894 FAIL address failed to verify
895 DEFER can't tell at present
899 verify_address(address_item *vaddr, FILE *f, int options, int callout,
900 int callout_overall, int callout_connect, uschar *se_mailfrom,
901 uschar *pm_mailfrom, BOOL *routed)
904 BOOL full_info = (f == NULL)? FALSE : (debug_selector != 0);
905 BOOL is_recipient = (options & vopt_is_recipient) != 0;
906 BOOL expn = (options & vopt_expn) != 0;
907 BOOL success_on_redirect = (options & vopt_success_on_redirect) != 0;
910 int verify_type = expn? v_expn :
911 address_test_mode? v_none :
912 is_recipient? v_recipient : v_sender;
913 address_item *addr_list;
914 address_item *addr_new = NULL;
915 address_item *addr_remote = NULL;
916 address_item *addr_local = NULL;
917 address_item *addr_succeed = NULL;
918 uschar **failure_ptr = is_recipient?
919 &recipient_verify_failure : &sender_verify_failure;
920 uschar *ko_prefix, *cr;
921 uschar *address = vaddr->address;
923 uschar null_sender[] = { 0 }; /* Ensure writeable memory */
925 /* Clear, just in case */
929 /* Set up a prefix and suffix for error message which allow us to use the same
930 output statements both in EXPN mode (where an SMTP response is needed) and when
931 debugging with an output file. */
935 ko_prefix = US"553 ";
938 else ko_prefix = cr = US"";
940 /* Add qualify domain if permitted; otherwise an unqualified address fails. */
942 if (parse_find_at(address) == NULL)
944 if ((options & vopt_qualify) == 0)
947 fprintf(f, "%sA domain is required for \"%s\"%s\n", ko_prefix, address,
949 *failure_ptr = US"qualify";
952 address = rewrite_address_qualify(address, is_recipient);
957 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
958 debug_printf("%s %s\n", address_test_mode? "Testing" : "Verifying", address);
961 /* Rewrite and report on it. Clear the domain and local part caches - these
962 may have been set by domains and local part tests during an ACL. */
964 if (global_rewrite_rules != NULL)
966 uschar *old = address;
967 address = rewrite_address(address, is_recipient, FALSE,
968 global_rewrite_rules, rewrite_existflags);
971 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->localpart_cache[i] = 0;
972 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->domain_cache[i] = 0;
973 if (f != NULL && !expn) fprintf(f, "Address rewritten as: %s\n", address);
977 /* If this is the real sender address, we must update sender_address at
978 this point, because it may be referred to in the routers. */
980 if ((options & (vopt_fake_sender|vopt_is_recipient)) == 0)
981 sender_address = address;
983 /* If the address was rewritten to <> no verification can be done, and we have
984 to return OK. This rewriting is permitted only for sender addresses; for other
985 addresses, such rewriting fails. */
987 if (address[0] == 0) return OK;
989 /* Save a copy of the sender address for re-instating if we change it to <>
990 while verifying a sender address (a nice bit of self-reference there). */
992 save_sender = sender_address;
994 /* Update the address structure with the possibly qualified and rewritten
995 address. Set it up as the starting address on the chain of new addresses. */
997 vaddr->address = address;
1000 /* We need a loop, because an address can generate new addresses. We must also
1001 cope with generated pipes and files at the top level. (See also the code and
1002 comment in deliver.c.) However, it is usually the case that the router for
1003 user's .forward files has its verify flag turned off.
1005 If an address generates more than one child, the loop is used only when
1006 full_info is set, and this can only be set locally. Remote enquiries just get
1007 information about the top level address, not anything that it generated. */
1009 while (addr_new != NULL)
1012 address_item *addr = addr_new;
1014 addr_new = addr->next;
1019 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1020 debug_printf("Considering %s\n", addr->address);
1023 /* Handle generated pipe, file or reply addresses. We don't get these
1024 when handling EXPN, as it does only one level of expansion. */
1026 if (testflag(addr, af_pfr))
1033 if (addr->address[0] == '>')
1035 allow = testflag(addr, af_allow_reply);
1036 fprintf(f, "%s -> mail %s", addr->parent->address, addr->address + 1);
1040 allow = (addr->address[0] == '|')?
1041 testflag(addr, af_allow_pipe) : testflag(addr, af_allow_file);
1042 fprintf(f, "%s -> %s", addr->parent->address, addr->address);
1045 if (addr->basic_errno == ERRNO_BADTRANSPORT)
1046 fprintf(f, "\n*** Error in setting up pipe, file, or autoreply:\n"
1047 "%s\n", addr->message);
1049 fprintf(f, "\n transport = %s\n", addr->transport->name);
1051 fprintf(f, " *** forbidden ***\n");
1056 /* Just in case some router parameter refers to it. */
1058 return_path = (addr->p.errors_address != NULL)?
1059 addr->p.errors_address : sender_address;
1061 /* Split the address into domain and local part, handling the %-hack if
1062 necessary, and then route it. While routing a sender address, set
1063 $sender_address to <> because that is what it will be if we were trying to
1064 send a bounce to the sender. */
1066 if (routed != NULL) *routed = FALSE;
1067 if ((rc = deliver_split_address(addr)) == OK)
1069 if (!is_recipient) sender_address = null_sender;
1070 rc = route_address(addr, &addr_local, &addr_remote, &addr_new,
1071 &addr_succeed, verify_type);
1072 sender_address = save_sender; /* Put back the real sender */
1075 /* If routing an address succeeded, set the flag that remembers, for use when
1076 an ACL cached a sender verify (in case a callout fails). Then if routing set
1077 up a list of hosts or the transport has a host list, and the callout option
1078 is set, and we aren't in a host checking run, do the callout verification,
1079 and set another flag that notes that a callout happened. */
1083 if (routed != NULL) *routed = TRUE;
1086 host_item *host_list = addr->host_list;
1088 /* Make up some data for use in the case where there is no remote
1091 transport_feedback tf = {
1092 NULL, /* interface (=> any) */
1093 US"smtp", /* port */
1094 US"smtp", /* protocol */
1096 US"$smtp_active_hostname", /* helo_data */
1097 FALSE, /* hosts_override */
1098 FALSE, /* hosts_randomize */
1099 FALSE, /* gethostbyname */
1100 TRUE, /* qualify_single */
1101 FALSE /* search_parents */
1104 /* If verification yielded a remote transport, we want to use that
1105 transport's options, so as to mimic what would happen if we were really
1106 sending a message to this address. */
1108 if (addr->transport != NULL && !addr->transport->info->local)
1110 (void)(addr->transport->setup)(addr->transport, addr, &tf, 0, 0, NULL);
1112 /* If the transport has hosts and the router does not, or if the
1113 transport is configured to override the router's hosts, we must build a
1114 host list of the transport's hosts, and find the IP addresses */
1116 if (tf.hosts != NULL && (host_list == NULL || tf.hosts_override))
1119 uschar *save_deliver_domain = deliver_domain;
1120 uschar *save_deliver_localpart = deliver_localpart;
1122 host_list = NULL; /* Ignore the router's hosts */
1124 deliver_domain = addr->domain;
1125 deliver_localpart = addr->local_part;
1126 s = expand_string(tf.hosts);
1127 deliver_domain = save_deliver_domain;
1128 deliver_localpart = save_deliver_localpart;
1132 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand list of hosts "
1133 "\"%s\" in %s transport for callout: %s", tf.hosts,
1134 addr->transport->name, expand_string_message);
1139 uschar *canonical_name;
1140 host_item *host, *nexthost;
1141 host_build_hostlist(&host_list, s, tf.hosts_randomize);
1143 /* Just ignore failures to find a host address. If we don't manage
1144 to find any addresses, the callout will defer. Note that more than
1145 one address may be found for a single host, which will result in
1146 additional host items being inserted into the chain. Hence we must
1147 save the next host first. */
1149 flags = HOST_FIND_BY_A;
1150 if (tf.qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
1151 if (tf.search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
1153 for (host = host_list; host != NULL; host = nexthost)
1155 nexthost = host->next;
1156 if (tf.gethostbyname ||
1157 string_is_ip_address(host->name, NULL) != 0)
1158 (void)host_find_byname(host, NULL, flags, &canonical_name, TRUE);
1160 (void)host_find_bydns(host, NULL, flags, NULL, NULL, NULL,
1161 &canonical_name, NULL);
1167 /* Can only do a callout if we have at least one host! If the callout
1168 fails, it will have set ${sender,recipient}_verify_failure. */
1170 if (host_list != NULL)
1172 HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n");
1173 if (host_checking && !host_checking_callout)
1176 debug_printf("... callout omitted by default when host testing\n"
1177 "(Use -bhc if you want the callouts to happen.)\n");
1181 rc = do_callout(addr, host_list, &tf, callout, callout_overall,
1182 callout_connect, options, se_mailfrom, pm_mailfrom);
1187 HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor "
1188 "transport provided a host list\n");
1193 /* Otherwise, any failure is a routing failure */
1195 else *failure_ptr = US"route";
1197 /* A router may return REROUTED if it has set up a child address as a result
1198 of a change of domain name (typically from widening). In this case we always
1199 want to continue to verify the new child. */
1201 if (rc == REROUTED) continue;
1203 /* Handle hard failures */
1210 address_item *p = addr->parent;
1212 fprintf(f, "%s%s %s", ko_prefix, full_info? addr->address : address,
1213 address_test_mode? "is undeliverable" : "failed to verify");
1214 if (!expn && admin_user)
1216 if (addr->basic_errno > 0)
1217 fprintf(f, ": %s", strerror(addr->basic_errno));
1218 if (addr->message != NULL)
1219 fprintf(f, ": %s", addr->message);
1222 /* Show parents iff doing full info */
1224 if (full_info) while (p != NULL)
1226 fprintf(f, "%s\n <-- %s", cr, p->address);
1229 fprintf(f, "%s\n", cr);
1232 if (!full_info) return copy_error(vaddr, addr, FAIL);
1238 else if (rc == DEFER)
1243 address_item *p = addr->parent;
1244 fprintf(f, "%s%s cannot be resolved at this time", ko_prefix,
1245 full_info? addr->address : address);
1246 if (!expn && admin_user)
1248 if (addr->basic_errno > 0)
1249 fprintf(f, ": %s", strerror(addr->basic_errno));
1250 if (addr->message != NULL)
1251 fprintf(f, ": %s", addr->message);
1252 else if (addr->basic_errno <= 0)
1253 fprintf(f, ": unknown error");
1256 /* Show parents iff doing full info */
1258 if (full_info) while (p != NULL)
1260 fprintf(f, "%s\n <-- %s", cr, p->address);
1263 fprintf(f, "%s\n", cr);
1266 if (!full_info) return copy_error(vaddr, addr, DEFER);
1267 else if (yield == OK) yield = DEFER;
1270 /* If we are handling EXPN, we do not want to continue to route beyond
1271 the top level (whose address is in "address"). */
1275 uschar *ok_prefix = US"250-";
1276 if (addr_new == NULL)
1278 if (addr_local == NULL && addr_remote == NULL)
1279 fprintf(f, "250 mail to <%s> is discarded\r\n", address);
1281 fprintf(f, "250 <%s>\r\n", address);
1283 else while (addr_new != NULL)
1285 address_item *addr2 = addr_new;
1286 addr_new = addr2->next;
1287 if (addr_new == NULL) ok_prefix = US"250 ";
1288 fprintf(f, "%s<%s>\r\n", ok_prefix, addr2->address);
1293 /* Successful routing other than EXPN. */
1297 /* Handle successful routing when short info wanted. Otherwise continue for
1298 other (generated) addresses. Short info is the operational case. Full info
1299 can be requested only when debug_selector != 0 and a file is supplied.
1301 There is a conflict between the use of aliasing as an alternate email
1302 address, and as a sort of mailing list. If an alias turns the incoming
1303 address into just one address (e.g. J.Caesar->jc44) you may well want to
1304 carry on verifying the generated address to ensure it is valid when
1305 checking incoming mail. If aliasing generates multiple addresses, you
1306 probably don't want to do this. Exim therefore treats the generation of
1307 just a single new address as a special case, and continues on to verify the
1308 generated address. */
1310 if (!full_info && /* Stop if short info wanted AND */
1311 (((addr_new == NULL || /* No new address OR */
1312 addr_new->next != NULL || /* More than one new address OR */
1313 testflag(addr_new, af_pfr))) /* New address is pfr */
1315 (addr_new != NULL && /* At least one new address AND */
1316 success_on_redirect))) /* success_on_redirect is set */
1318 if (f != NULL) fprintf(f, "%s %s\n", address,
1319 address_test_mode? "is deliverable" : "verified");
1321 /* If we have carried on to verify a child address, we want the value
1322 of $address_data to be that of the child */
1324 vaddr->p.address_data = addr->p.address_data;
1328 } /* Loop for generated addresses */
1330 /* Display the full results of the successful routing, including any generated
1331 addresses. Control gets here only when full_info is set, which requires f not
1332 to be NULL, and this occurs only when a top-level verify is called with the
1333 debugging switch on.
1335 If there are no local and no remote addresses, and there were no pipes, files,
1336 or autoreplies, and there were no errors or deferments, the message is to be
1337 discarded, usually because of the use of :blackhole: in an alias file. */
1339 if (allok && addr_local == NULL && addr_remote == NULL)
1341 fprintf(f, "mail to %s is discarded\n", address);
1345 for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++)
1347 while (addr_list != NULL)
1349 address_item *addr = addr_list;
1350 address_item *p = addr->parent;
1351 addr_list = addr->next;
1353 fprintf(f, "%s", CS addr->address);
1354 #ifdef EXPERIMENTAL_SRS
1355 if(addr->p.srs_sender)
1356 fprintf(f, " [srs = %s]", addr->p.srs_sender);
1359 /* If the address is a duplicate, show something about it. */
1361 if (!testflag(addr, af_pfr))
1364 if ((tnode = tree_search(tree_duplicates, addr->unique)) != NULL)
1365 fprintf(f, " [duplicate, would not be delivered]");
1366 else tree_add_duplicate(addr->unique, addr);
1369 /* Now show its parents */
1373 fprintf(f, "\n <-- %s", p->address);
1378 /* Show router, and transport */
1380 fprintf(f, "router = %s, ", addr->router->name);
1381 fprintf(f, "transport = %s\n", (addr->transport == NULL)? US"unset" :
1382 addr->transport->name);
1384 /* Show any hosts that are set up by a router unless the transport
1385 is going to override them; fiddle a bit to get a nice format. */
1387 if (addr->host_list != NULL && addr->transport != NULL &&
1388 !addr->transport->overrides_hosts)
1393 for (h = addr->host_list; h != NULL; h = h->next)
1395 int len = Ustrlen(h->name);
1396 if (len > maxlen) maxlen = len;
1397 len = (h->address != NULL)? Ustrlen(h->address) : 7;
1398 if (len > maxaddlen) maxaddlen = len;
1400 for (h = addr->host_list; h != NULL; h = h->next)
1402 int len = Ustrlen(h->name);
1403 fprintf(f, " host %s ", h->name);
1404 while (len++ < maxlen) fprintf(f, " ");
1405 if (h->address != NULL)
1407 fprintf(f, "[%s] ", h->address);
1408 len = Ustrlen(h->address);
1410 else if (!addr->transport->info->local) /* Omit [unknown] for local */
1412 fprintf(f, "[unknown] ");
1416 while (len++ < maxaddlen) fprintf(f," ");
1417 if (h->mx >= 0) fprintf(f, "MX=%d", h->mx);
1418 if (h->port != PORT_NONE) fprintf(f, " port=%d", h->port);
1419 if (h->status == hstatus_unusable) fprintf(f, " ** unusable **");
1426 /* Will be DEFER or FAIL if any one address has, only for full_info (which is
1427 the -bv or -bt case). */
1435 /*************************************************
1436 * Check headers for syntax errors *
1437 *************************************************/
1439 /* This function checks those header lines that contain addresses, and verifies
1440 that all the addresses therein are syntactially correct.
1443 msgptr where to put an error message
1450 verify_check_headers(uschar **msgptr)
1455 for (h = header_list; h != NULL; h = h->next)
1457 if (h->type != htype_from &&
1458 h->type != htype_reply_to &&
1459 h->type != htype_sender &&
1460 h->type != htype_to &&
1461 h->type != htype_cc &&
1462 h->type != htype_bcc)
1465 colon = Ustrchr(h->text, ':');
1467 while (isspace(*s)) s++;
1469 parse_allow_group = TRUE; /* Allow group syntax */
1471 /* Loop for multiple addresses in the header */
1475 uschar *ss = parse_find_address_end(s, FALSE);
1476 uschar *recipient, *errmess;
1477 int terminator = *ss;
1478 int start, end, domain;
1480 /* Temporarily terminate the string at this point, and extract the
1481 operative address within. */
1484 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
1487 /* Permit an unqualified address only if the message is local, or if the
1488 sending host is configured to be permitted to send them. */
1490 if (recipient != NULL && domain == 0)
1492 if (h->type == htype_from || h->type == htype_sender)
1494 if (!allow_unqualified_sender) recipient = NULL;
1498 if (!allow_unqualified_recipient) recipient = NULL;
1500 if (recipient == NULL) errmess = US"unqualified address not permitted";
1503 /* It's an error if no address could be extracted, except for the special
1504 case of an empty address. */
1506 if (recipient == NULL && Ustrcmp(errmess, "empty address") != 0)
1508 uschar *verb = US"is";
1513 /* Arrange not to include any white space at the end in the
1514 error message or the header name. */
1516 while (t > s && isspace(t[-1])) t--;
1517 while (tt > h->text && isspace(tt[-1])) tt--;
1519 /* Add the address that failed to the error message, since in a
1520 header with very many addresses it is sometimes hard to spot
1521 which one is at fault. However, limit the amount of address to
1522 quote - cases have been seen where, for example, a missing double
1523 quote in a humungous To: header creates an "address" that is longer
1524 than string_sprintf can handle. */
1533 *msgptr = string_printing(
1534 string_sprintf("%s: failing address in \"%.*s:\" header %s: %.*s",
1535 errmess, tt - h->text, h->text, verb, len, s));
1540 /* Advance to the next address */
1542 s = ss + (terminator? 1:0);
1543 while (isspace(*s)) s++;
1544 } /* Next address */
1552 /*************************************************
1553 * Check for blind recipients *
1554 *************************************************/
1556 /* This function checks that every (envelope) recipient is mentioned in either
1557 the To: or Cc: header lines, thus detecting blind carbon copies.
1559 There are two ways of scanning that could be used: either scan the header lines
1560 and tick off the recipients, or scan the recipients and check the header lines.
1561 The original proposed patch did the former, but I have chosen to do the latter,
1562 because (a) it requires no memory and (b) will use fewer resources when there
1563 are many addresses in To: and/or Cc: and only one or two envelope recipients.
1566 Returns: OK if there are no blind recipients
1567 FAIL if there is at least one blind recipient
1571 verify_check_notblind(void)
1574 for (i = 0; i < recipients_count; i++)
1578 uschar *address = recipients_list[i].address;
1580 for (h = header_list; !found && h != NULL; h = h->next)
1584 if (h->type != htype_to && h->type != htype_cc) continue;
1586 colon = Ustrchr(h->text, ':');
1588 while (isspace(*s)) s++;
1590 parse_allow_group = TRUE; /* Allow group syntax */
1592 /* Loop for multiple addresses in the header */
1596 uschar *ss = parse_find_address_end(s, FALSE);
1597 uschar *recipient,*errmess;
1598 int terminator = *ss;
1599 int start, end, domain;
1601 /* Temporarily terminate the string at this point, and extract the
1602 operative address within. */
1605 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
1608 /* If we found a valid recipient that has a domain, compare it with the
1609 envelope recipient. Local parts are compared case-sensitively, domains
1610 case-insensitively. By comparing from the start with length "domain", we
1611 include the "@" at the end, which ensures that we are comparing the whole
1612 local part of each address. */
1614 if (recipient != NULL && domain != 0)
1616 found = Ustrncmp(recipient, address, domain) == 0 &&
1617 strcmpic(recipient + domain, address + domain) == 0;
1621 /* Advance to the next address */
1623 s = ss + (terminator? 1:0);
1624 while (isspace(*s)) s++;
1625 } /* Next address */
1626 } /* Next header (if found is false) */
1628 if (!found) return FAIL;
1629 } /* Next recipient */
1636 /*************************************************
1637 * Find if verified sender *
1638 *************************************************/
1640 /* Usually, just a single address is verified as the sender of the message.
1641 However, Exim can be made to verify other addresses as well (often related in
1642 some way), and this is useful in some environments. There may therefore be a
1643 chain of such addresses that have previously been tested. This function finds
1644 whether a given address is on the chain.
1646 Arguments: the address to be verified
1647 Returns: pointer to an address item, or NULL
1651 verify_checked_sender(uschar *sender)
1654 for (addr = sender_verified_list; addr != NULL; addr = addr->next)
1655 if (Ustrcmp(sender, addr->address) == 0) break;
1663 /*************************************************
1664 * Get valid header address *
1665 *************************************************/
1667 /* Scan the originator headers of the message, looking for an address that
1668 verifies successfully. RFC 822 says:
1670 o The "Sender" field mailbox should be sent notices of
1671 any problems in transport or delivery of the original
1672 messages. If there is no "Sender" field, then the
1673 "From" field mailbox should be used.
1675 o If the "Reply-To" field exists, then the reply should
1676 go to the addresses indicated in that field and not to
1677 the address(es) indicated in the "From" field.
1679 So we check a Sender field if there is one, else a Reply_to field, else a From
1680 field. As some strange messages may have more than one of these fields,
1681 especially if they are resent- fields, check all of them if there is more than
1685 user_msgptr points to where to put a user error message
1686 log_msgptr points to where to put a log error message
1687 callout timeout for callout check (passed to verify_address())
1688 callout_overall overall callout timeout (ditto)
1689 callout_connect connect callout timeout (ditto)
1690 se_mailfrom mailfrom for verify; NULL => ""
1691 pm_mailfrom sender for pm callout check (passed to verify_address())
1692 options callout options (passed to verify_address())
1693 verrno where to put the address basic_errno
1695 If log_msgptr is set to something without setting user_msgptr, the caller
1696 normally uses log_msgptr for both things.
1698 Returns: result of the verification attempt: OK, FAIL, or DEFER;
1699 FAIL is given if no appropriate headers are found
1703 verify_check_header_address(uschar **user_msgptr, uschar **log_msgptr,
1704 int callout, int callout_overall, int callout_connect, uschar *se_mailfrom,
1705 uschar *pm_mailfrom, int options, int *verrno)
1707 static int header_types[] = { htype_sender, htype_reply_to, htype_from };
1711 for (i = 0; i < 3; i++)
1714 for (h = header_list; h != NULL; h = h->next)
1716 int terminator, new_ok;
1717 uschar *s, *ss, *endname;
1719 if (h->type != header_types[i]) continue;
1720 s = endname = Ustrchr(h->text, ':') + 1;
1724 address_item *vaddr;
1726 while (isspace(*s) || *s == ',') s++;
1727 if (*s == 0) break; /* End of header */
1729 ss = parse_find_address_end(s, FALSE);
1731 /* The terminator is a comma or end of header, but there may be white
1732 space preceding it (including newline for the last address). Move back
1733 past any white space so we can check against any cached envelope sender
1734 address verifications. */
1736 while (isspace(ss[-1])) ss--;
1740 HDEBUG(D_verify) debug_printf("verifying %.*s header address %s\n",
1741 (int)(endname - h->text), h->text, s);
1743 /* See if we have already verified this address as an envelope sender,
1744 and if so, use the previous answer. */
1746 vaddr = verify_checked_sender(s);
1748 if (vaddr != NULL && /* Previously checked */
1749 (callout <= 0 || /* No callout needed; OR */
1750 vaddr->special_action > 256)) /* Callout was done */
1752 new_ok = vaddr->special_action & 255;
1753 HDEBUG(D_verify) debug_printf("previously checked as envelope sender\n");
1754 *ss = terminator; /* Restore shortened string */
1757 /* Otherwise we run the verification now. We must restore the shortened
1758 string before running the verification, so the headers are correct, in
1759 case there is any rewriting. */
1763 int start, end, domain;
1764 uschar *address = parse_extract_address(s, log_msgptr, &start,
1765 &end, &domain, FALSE);
1769 /* If verification failed because of a syntax error, fail this
1770 function, and ensure that the failing address gets added to the error
1773 if (address == NULL)
1776 if (*log_msgptr != NULL)
1778 while (ss > s && isspace(ss[-1])) ss--;
1779 *log_msgptr = string_sprintf("syntax error in '%.*s' header when "
1780 "scanning for sender: %s in \"%.*s\"",
1781 endname - h->text, h->text, *log_msgptr, ss - s, s);
1786 /* Else go ahead with the sender verification. But it isn't *the*
1787 sender of the message, so set vopt_fake_sender to stop sender_address
1788 being replaced after rewriting or qualification. */
1792 vaddr = deliver_make_addr(address, FALSE);
1793 new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender,
1794 callout, callout_overall, callout_connect, se_mailfrom,
1799 /* We now have the result, either newly found, or cached. If we are
1800 giving out error details, set a specific user error. This means that the
1801 last of these will be returned to the user if all three fail. We do not
1802 set a log message - the generic one below will be used. */
1806 *verrno = vaddr->basic_errno;
1807 if (smtp_return_error_details)
1809 *user_msgptr = string_sprintf("Rejected after DATA: "
1810 "could not verify \"%.*s\" header address\n%s: %s",
1811 endname - h->text, h->text, vaddr->address, vaddr->message);
1815 /* Success or defer */
1817 if (new_ok == OK) return OK;
1818 if (new_ok == DEFER) yield = DEFER;
1820 /* Move on to any more addresses in the header */
1827 if (yield == FAIL && *log_msgptr == NULL)
1828 *log_msgptr = US"there is no valid sender in any header line";
1830 if (yield == DEFER && *log_msgptr == NULL)
1831 *log_msgptr = US"all attempts to verify a sender in a header line deferred";
1839 /*************************************************
1840 * Get RFC 1413 identification *
1841 *************************************************/
1843 /* Attempt to get an id from the sending machine via the RFC 1413 protocol. If
1844 the timeout is set to zero, then the query is not done. There may also be lists
1845 of hosts and nets which are exempt. To guard against malefactors sending
1846 non-printing characters which could, for example, disrupt a message's headers,
1847 make sure the string consists of printing characters only.
1850 port the port to connect to; usually this is IDENT_PORT (113), but when
1851 running in the test harness with -bh a different value is used.
1855 Side effect: any received ident value is put in sender_ident (NULL otherwise)
1859 verify_get_ident(int port)
1861 int sock, host_af, qlen;
1862 int received_sender_port, received_interface_port, n;
1864 uschar buffer[2048];
1866 /* Default is no ident. Check whether we want to do an ident check for this
1869 sender_ident = NULL;
1870 if (rfc1413_query_timeout <= 0 || verify_check_host(&rfc1413_hosts) != OK)
1873 DEBUG(D_ident) debug_printf("doing ident callback\n");
1875 /* Set up a connection to the ident port of the remote host. Bind the local end
1876 to the incoming interface address. If the sender host address is an IPv6
1877 address, the incoming interface address will also be IPv6. */
1879 host_af = (Ustrchr(sender_host_address, ':') == NULL)? AF_INET : AF_INET6;
1880 sock = ip_socket(SOCK_STREAM, host_af);
1881 if (sock < 0) return;
1883 if (ip_bind(sock, host_af, interface_address, 0) < 0)
1885 DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n",
1890 if (ip_connect(sock, host_af, sender_host_address, port, rfc1413_query_timeout)
1893 if (errno == ETIMEDOUT && (log_extra_selector & LX_ident_timeout) != 0)
1895 log_write(0, LOG_MAIN, "ident connection to %s timed out",
1896 sender_host_address);
1900 DEBUG(D_ident) debug_printf("ident connection to %s failed: %s\n",
1901 sender_host_address, strerror(errno));
1906 /* Construct and send the query. */
1908 sprintf(CS buffer, "%d , %d\r\n", sender_host_port, interface_port);
1909 qlen = Ustrlen(buffer);
1910 if (send(sock, buffer, qlen, 0) < 0)
1912 DEBUG(D_ident) debug_printf("ident send failed: %s\n", strerror(errno));
1916 /* Read a response line. We put it into the rest of the buffer, using several
1917 recv() calls if necessary. */
1925 int size = sizeof(buffer) - (p - buffer);
1927 if (size <= 0) goto END_OFF; /* Buffer filled without seeing \n. */
1928 count = ip_recv(sock, p, size, rfc1413_query_timeout);
1929 if (count <= 0) goto END_OFF; /* Read error or EOF */
1931 /* Scan what we just read, to see if we have reached the terminating \r\n. Be
1932 generous, and accept a plain \n terminator as well. The only illegal
1935 for (pp = p; pp < p + count; pp++)
1937 if (*pp == 0) goto END_OFF; /* Zero octet not allowed */
1940 if (pp[-1] == '\r') pp--;
1942 goto GOT_DATA; /* Break out of both loops */
1946 /* Reached the end of the data without finding \n. Let the loop continue to
1947 read some more, if there is room. */
1954 /* We have received a line of data. Check it carefully. It must start with the
1955 same two port numbers that we sent, followed by data as defined by the RFC. For
1958 12345 , 25 : USERID : UNIX :root
1960 However, the amount of white space may be different to what we sent. In the
1961 "osname" field there may be several sub-fields, comma separated. The data we
1962 actually want to save follows the third colon. Some systems put leading spaces
1963 in it - we discard those. */
1965 if (sscanf(CS buffer + qlen, "%d , %d%n", &received_sender_port,
1966 &received_interface_port, &n) != 2 ||
1967 received_sender_port != sender_host_port ||
1968 received_interface_port != interface_port)
1971 p = buffer + qlen + n;
1972 while(isspace(*p)) p++;
1973 if (*p++ != ':') goto END_OFF;
1974 while(isspace(*p)) p++;
1975 if (Ustrncmp(p, "USERID", 6) != 0) goto END_OFF;
1977 while(isspace(*p)) p++;
1978 if (*p++ != ':') goto END_OFF;
1979 while (*p != 0 && *p != ':') p++;
1980 if (*p++ == 0) goto END_OFF;
1981 while(isspace(*p)) p++;
1982 if (*p == 0) goto END_OFF;
1984 /* The rest of the line is the data we want. We turn it into printing
1985 characters when we save it, so that it cannot mess up the format of any logging
1986 or Received: lines into which it gets inserted. We keep a maximum of 127
1989 sender_ident = string_printing(string_copyn(p, 127));
1990 DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident);
2000 /*************************************************
2001 * Match host to a single host-list item *
2002 *************************************************/
2004 /* This function compares a host (name or address) against a single item
2005 from a host list. The host name gets looked up if it is needed and is not
2006 already known. The function is called from verify_check_this_host() via
2007 match_check_list(), which is why most of its arguments are in a single block.
2010 arg the argument block (see below)
2011 ss the host-list item
2012 valueptr where to pass back looked up data, or NULL
2013 error for error message when returning ERROR
2016 host_name (a) the host name, or
2017 (b) NULL, implying use sender_host_name and
2018 sender_host_aliases, looking them up if required, or
2019 (c) the empty string, meaning that only IP address matches
2021 host_address the host address
2022 host_ipv4 the IPv4 address taken from an IPv6 one
2026 DEFER lookup deferred
2027 ERROR (a) failed to find the host name or IP address, or
2028 (b) unknown lookup type specified, or
2029 (c) host name encountered when only IP addresses are
2034 check_host(void *arg, uschar *ss, uschar **valueptr, uschar **error)
2036 check_host_block *cb = (check_host_block *)arg;
2039 BOOL iplookup = FALSE;
2040 BOOL isquery = FALSE;
2041 BOOL isiponly = cb->host_name != NULL && cb->host_name[0] == 0;
2046 /* Optimize for the special case when the pattern is "*". */
2048 if (*ss == '*' && ss[1] == 0) return OK;
2050 /* If the pattern is empty, it matches only in the case when there is no host -
2051 this can occur in ACL checking for SMTP input using the -bs option. In this
2052 situation, the host address is the empty string. */
2054 if (cb->host_address[0] == 0) return (*ss == 0)? OK : FAIL;
2055 if (*ss == 0) return FAIL;
2057 /* If the pattern is precisely "@" then match against the primary host name,
2058 provided that host name matching is permitted; if it's "@[]" match against the
2059 local host's IP addresses. */
2065 if (isiponly) return ERROR;
2066 ss = primary_hostname;
2068 else if (Ustrcmp(ss, "@[]") == 0)
2070 ip_address_item *ip;
2071 for (ip = host_find_interfaces(); ip != NULL; ip = ip->next)
2072 if (Ustrcmp(ip->address, cb->host_address) == 0) return OK;
2077 /* If the pattern is an IP address, optionally followed by a bitmask count, do
2078 a (possibly masked) comparision with the current IP address. */
2080 if (string_is_ip_address(ss, &maskoffset) != 0)
2081 return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL);
2083 /* The pattern is not an IP address. A common error that people make is to omit
2084 one component of an IPv4 address, either by accident, or believing that, for
2085 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,
2086 which it isn't. (Those applications that do accept 1.2.3 as an IP address
2087 interpret it as 1.2.0.3 because the final component becomes 16-bit - this is an
2088 ancient specification.) To aid in debugging these cases, we give a specific
2089 error if the pattern contains only digits and dots or contains a slash preceded
2090 only by digits and dots (a slash at the start indicates a file name and of
2091 course slashes may be present in lookups, but not preceded only by digits and
2094 for (t = ss; isdigit(*t) || *t == '.'; t++);
2095 if (*t == 0 || (*t == '/' && t != ss))
2097 *error = US"malformed IPv4 address or address mask";
2101 /* See if there is a semicolon in the pattern */
2103 semicolon = Ustrchr(ss, ';');
2105 /* If we are doing an IP address only match, then all lookups must be IP
2106 address lookups, even if there is no "net-". */
2110 iplookup = semicolon != NULL;
2113 /* Otherwise, if the item is of the form net[n]-lookup;<file|query> then it is
2114 a lookup on a masked IP network, in textual form. We obey this code even if we
2115 have already set iplookup, so as to skip over the "net-" prefix and to set the
2116 mask length. The net- stuff really only applies to single-key lookups where the
2117 key is implicit. For query-style lookups the key is specified in the query.
2118 From release 4.30, the use of net- for query style is no longer needed, but we
2119 retain it for backward compatibility. */
2121 if (Ustrncmp(ss, "net", 3) == 0 && semicolon != NULL)
2124 for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0';
2125 if (mlen == 0 && t == ss+3) mlen = -1; /* No mask supplied */
2126 iplookup = (*t++ == '-');
2130 /* Do the IP address lookup if that is indeed what we have */
2138 uschar *filename, *key, *result;
2141 /* Find the search type */
2143 search_type = search_findtype(t, semicolon - t);
2145 if (search_type < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
2146 search_error_message);
2148 /* Adjust parameters for the type of lookup. For a query-style lookup, there
2149 is no file name, and the "key" is just the query. For query-style with a file
2150 name, we have to fish the file off the start of the query. For a single-key
2151 lookup, the key is the current IP address, masked appropriately, and
2152 reconverted to text form, with the mask appended. For IPv6 addresses, specify
2153 dot separators instead of colons. */
2155 if (mac_islookup(search_type, lookup_absfilequery))
2157 filename = semicolon + 1;
2159 while (*key != 0 && !isspace(*key)) key++;
2160 filename = string_copyn(filename, key - filename);
2161 while (isspace(*key)) key++;
2163 else if (mac_islookup(search_type, lookup_querystyle))
2166 key = semicolon + 1;
2170 insize = host_aton(cb->host_address, incoming);
2171 host_mask(insize, incoming, mlen);
2172 (void)host_nmtoa(insize, incoming, mlen, buffer, '.');
2174 filename = semicolon + 1;
2177 /* Now do the actual lookup; note that there is no search_close() because
2178 of the caching arrangements. */
2180 handle = search_open(filename, search_type, 0, NULL, NULL);
2181 if (handle == NULL) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
2182 search_error_message);
2183 result = search_find(handle, filename, key, -1, NULL, 0, 0, NULL);
2184 if (valueptr != NULL) *valueptr = result;
2185 return (result != NULL)? OK : search_find_defer? DEFER: FAIL;
2188 /* The pattern is not an IP address or network reference of any kind. That is,
2189 it is a host name pattern. If this is an IP only match, there's an error in the
2194 *error = US"cannot match host name in match_ip list";
2198 /* Check the characters of the pattern to see if they comprise only letters,
2199 digits, full stops, and hyphens (the constituents of domain names). Allow
2200 underscores, as they are all too commonly found. Sigh. Also, if
2201 allow_utf8_domains is set, allow top-bit characters. */
2203 for (t = ss; *t != 0; t++)
2204 if (!isalnum(*t) && *t != '.' && *t != '-' && *t != '_' &&
2205 (!allow_utf8_domains || *t < 128)) break;
2207 /* If the pattern is a complete domain name, with no fancy characters, look up
2208 its IP address and match against that. Note that a multi-homed host will add
2209 items to the chain. */
2220 rc = host_find_byname(&h, NULL, HOST_FIND_QUALIFY_SINGLE, NULL, FALSE);
2221 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2224 for (hh = &h; hh != NULL; hh = hh->next)
2226 if (host_is_in_net(hh->address, cb->host_address, 0)) return OK;
2230 if (rc == HOST_FIND_AGAIN) return DEFER;
2231 *error = string_sprintf("failed to find IP address for %s", ss);
2235 /* Almost all subsequent comparisons require the host name, and can be done
2236 using the general string matching function. When this function is called for
2237 outgoing hosts, the name is always given explicitly. If it is NULL, it means we
2238 must use sender_host_name and its aliases, looking them up if necessary. */
2240 if (cb->host_name != NULL) /* Explicit host name given */
2241 return match_check_string(cb->host_name, ss, -1, TRUE, TRUE, TRUE,
2244 /* Host name not given; in principle we need the sender host name and its
2245 aliases. However, for query-style lookups, we do not need the name if the
2246 query does not contain $sender_host_name. From release 4.23, a reference to
2247 $sender_host_name causes it to be looked up, so we don't need to do the lookup
2250 if ((semicolon = Ustrchr(ss, ';')) != NULL)
2253 int partial, affixlen, starflags, id;
2256 id = search_findtype_partial(ss, &partial, &affix, &affixlen, &starflags);
2259 if (id < 0) /* Unknown lookup type */
2261 log_write(0, LOG_MAIN|LOG_PANIC, "%s in host list item \"%s\"",
2262 search_error_message, ss);
2265 isquery = mac_islookup(id, lookup_querystyle|lookup_absfilequery);
2270 switch(match_check_string(US"", ss, -1, TRUE, TRUE, TRUE, valueptr))
2273 case DEFER: return DEFER;
2274 default: return FAIL;
2278 /* Not a query-style lookup; must ensure the host name is present, and then we
2279 do a check on the name and all its aliases. */
2281 if (sender_host_name == NULL)
2283 HDEBUG(D_host_lookup)
2284 debug_printf("sender host name required, to match against %s\n", ss);
2285 if (host_lookup_failed || host_name_lookup() != OK)
2287 *error = string_sprintf("failed to find host name for %s",
2288 sender_host_address);;
2291 host_build_sender_fullhost();
2294 /* Match on the sender host name, using the general matching function */
2296 switch(match_check_string(sender_host_name, ss, -1, TRUE, TRUE, TRUE,
2300 case DEFER: return DEFER;
2303 /* If there are aliases, try matching on them. */
2305 aliases = sender_host_aliases;
2306 while (*aliases != NULL)
2308 switch(match_check_string(*aliases++, ss, -1, TRUE, TRUE, TRUE, valueptr))
2311 case DEFER: return DEFER;
2320 /*************************************************
2321 * Check a specific host matches a host list *
2322 *************************************************/
2324 /* This function is passed a host list containing items in a number of
2325 different formats and the identity of a host. Its job is to determine whether
2326 the given host is in the set of hosts defined by the list. The host name is
2327 passed as a pointer so that it can be looked up if needed and not already
2328 known. This is commonly the case when called from verify_check_host() to check
2329 an incoming connection. When called from elsewhere the host name should usually
2332 This function is now just a front end to match_check_list(), which runs common
2333 code for scanning a list. We pass it the check_host() function to perform a
2337 listptr pointer to the host list
2338 cache_bits pointer to cache for named lists, or NULL
2339 host_name the host name or NULL, implying use sender_host_name and
2340 sender_host_aliases, looking them up if required
2341 host_address the IP address
2342 valueptr if not NULL, data from a lookup is passed back here
2344 Returns: OK if the host is in the defined set
2345 FAIL if the host is not in the defined set,
2346 DEFER if a data lookup deferred (not a host lookup)
2348 If the host name was needed in order to make a comparison, and could not be
2349 determined from the IP address, the result is FAIL unless the item
2350 "+allow_unknown" was met earlier in the list, in which case OK is returned. */
2353 verify_check_this_host(uschar **listptr, unsigned int *cache_bits,
2354 uschar *host_name, uschar *host_address, uschar **valueptr)
2357 unsigned int *local_cache_bits = cache_bits;
2358 uschar *save_host_address = deliver_host_address;
2359 check_host_block cb;
2360 cb.host_name = host_name;
2361 cb.host_address = host_address;
2363 if (valueptr != NULL) *valueptr = NULL;
2365 /* If the host address starts off ::ffff: it is an IPv6 address in
2366 IPv4-compatible mode. Find the IPv4 part for checking against IPv4
2369 cb.host_ipv4 = (Ustrncmp(host_address, "::ffff:", 7) == 0)?
2370 host_address + 7 : host_address;
2372 /* During the running of the check, put the IP address into $host_address. In
2373 the case of calls from the smtp transport, it will already be there. However,
2374 in other calls (e.g. when testing ignore_target_hosts), it won't. Just to be on
2375 the safe side, any existing setting is preserved, though as I write this
2376 (November 2004) I can't see any cases where it is actually needed. */
2378 deliver_host_address = host_address;
2379 rc = match_check_list(
2380 listptr, /* the list */
2381 0, /* separator character */
2382 &hostlist_anchor, /* anchor pointer */
2383 &local_cache_bits, /* cache pointer */
2384 check_host, /* function for testing */
2385 &cb, /* argument for function */
2386 MCL_HOST, /* type of check */
2387 (host_address == sender_host_address)?
2388 US"host" : host_address, /* text for debugging */
2389 valueptr); /* where to pass back data */
2390 deliver_host_address = save_host_address;
2397 /*************************************************
2398 * Check the remote host matches a list *
2399 *************************************************/
2401 /* This is a front end to verify_check_this_host(), created because checking
2402 the remote host is a common occurrence. With luck, a good compiler will spot
2403 the tail recursion and optimize it. If there's no host address, this is
2404 command-line SMTP input - check against an empty string for the address.
2407 listptr pointer to the host list
2409 Returns: the yield of verify_check_this_host(),
2410 i.e. OK, FAIL, or DEFER
2414 verify_check_host(uschar **listptr)
2416 return verify_check_this_host(listptr, sender_host_cache, NULL,
2417 (sender_host_address == NULL)? US"" : sender_host_address, NULL);
2424 /*************************************************
2425 * Invert an IP address for a DNS black list *
2426 *************************************************/
2430 buffer where to put the answer
2431 address the address to invert
2435 invert_address(uschar *buffer, uschar *address)
2438 uschar *bptr = buffer;
2440 /* If this is an IPv4 address mapped into IPv6 format, adjust the pointer
2441 to the IPv4 part only. */
2443 if (Ustrncmp(address, "::ffff:", 7) == 0) address += 7;
2445 /* Handle IPv4 address: when HAVE_IPV6 is false, the result of host_aton() is
2448 if (host_aton(address, bin) == 1)
2452 for (i = 0; i < 4; i++)
2454 sprintf(CS bptr, "%d.", x & 255);
2455 while (*bptr) bptr++;
2460 /* Handle IPv6 address. Actually, as far as I know, there are no IPv6 addresses
2461 in any DNS black lists, and the format in which they will be looked up is
2462 unknown. This is just a guess. */
2468 for (j = 3; j >= 0; j--)
2471 for (i = 0; i < 8; i++)
2473 sprintf(CS bptr, "%x.", x & 15);
2474 while (*bptr) bptr++;
2481 /* Remove trailing period -- this is needed so that both arbitrary
2482 dnsbl keydomains and inverted addresses may be combined with the
2483 same format string, "%s.%s" */
2490 /*************************************************
2491 * Perform a single dnsbl lookup *
2492 *************************************************/
2494 /* This function is called from verify_check_dnsbl() below. It is also called
2495 recursively from within itself when domain and domain_txt are different
2496 pointers, in order to get the TXT record from the alternate domain.
2499 domain the outer dnsbl domain
2500 domain_txt alternate domain to lookup TXT record on success; when the
2501 same domain is to be used, domain_txt == domain (that is,
2502 the pointers must be identical, not just the text)
2503 keydomain the current keydomain (for debug message)
2504 prepend subdomain to lookup (like keydomain, but
2505 reversed if IP address)
2506 iplist the list of matching IP addresses, or NULL for "any"
2507 bitmask true if bitmask matching is wanted
2508 invert_result true if result to be inverted
2509 defer_return what to return for a defer
2511 Returns: OK if lookup succeeded
2516 one_check_dnsbl(uschar *domain, uschar *domain_txt, uschar *keydomain,
2517 uschar *prepend, uschar *iplist, BOOL bitmask, BOOL invert_result,
2523 dnsbl_cache_block *cb;
2524 int old_pool = store_pool;
2525 uschar query[256]; /* DNS domain max length */
2527 /* Construct the specific query domainname */
2529 if (!string_format(query, sizeof(query), "%s.%s", prepend, domain))
2531 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
2532 "(ignored): %s...", query);
2536 /* Look for this query in the cache. */
2538 t = tree_search(dnsbl_cache, query);
2540 /* If not cached from a previous lookup, we must do a DNS lookup, and
2541 cache the result in permanent memory. */
2545 store_pool = POOL_PERM;
2547 /* Set up a tree entry to cache the lookup */
2549 t = store_get(sizeof(tree_node) + Ustrlen(query));
2550 Ustrcpy(t->name, query);
2551 t->data.ptr = cb = store_get(sizeof(dnsbl_cache_block));
2552 (void)tree_insertnode(&dnsbl_cache, t);
2554 /* Do the DNS loopup . */
2556 HDEBUG(D_dnsbl) debug_printf("new DNS lookup for %s\n", query);
2557 cb->rc = dns_basic_lookup(&dnsa, query, T_A);
2558 cb->text_set = FALSE;
2562 /* If the lookup succeeded, cache the RHS address. The code allows for
2563 more than one address - this was for complete generality and the possible
2564 use of A6 records. However, A6 records have been reduced to experimental
2565 status (August 2001) and may die out. So they may never get used at all,
2566 let alone in dnsbl records. However, leave the code here, just in case.
2568 Quite apart from one A6 RR generating multiple addresses, there are DNS
2569 lists that return more than one A record, so we must handle multiple
2570 addresses generated in that way as well. */
2572 if (cb->rc == DNS_SUCCEED)
2575 dns_address **addrp = &(cb->rhs);
2576 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2578 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
2580 if (rr->type == T_A)
2582 dns_address *da = dns_address_from_rr(&dnsa, rr);
2586 while (da->next != NULL) da = da->next;
2587 addrp = &(da->next);
2592 /* If we didn't find any A records, change the return code. This can
2593 happen when there is a CNAME record but there are no A records for what
2596 if (cb->rhs == NULL) cb->rc = DNS_NODATA;
2599 store_pool = old_pool;
2602 /* Previous lookup was cached */
2606 HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
2610 /* We now have the result of the DNS lookup, either newly done, or cached
2611 from a previous call. If the lookup succeeded, check against the address
2612 list if there is one. This may be a positive equality list (introduced by
2613 "="), a negative equality list (introduced by "!="), a positive bitmask
2614 list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/
2616 if (cb->rc == DNS_SUCCEED)
2618 dns_address *da = NULL;
2619 uschar *addlist = cb->rhs->address;
2621 /* For A and AAAA records, there may be multiple addresses from multiple
2622 records. For A6 records (currently not expected to be used) there may be
2623 multiple addresses from a single record. */
2625 for (da = cb->rhs->next; da != NULL; da = da->next)
2626 addlist = string_sprintf("%s, %s", addlist, da->address);
2628 HDEBUG(D_dnsbl) debug_printf("DNS lookup for %s succeeded (yielding %s)\n",
2631 /* Address list check; this can be either for equality, or via a bitmask.
2632 In the latter case, all the bits must match. */
2638 uschar *ptr = iplist;
2640 while (string_nextinlist(&ptr, &ipsep, ip, sizeof(ip)) != NULL)
2642 /* Handle exact matching */
2645 for (da = cb->rhs; da != NULL; da = da->next)
2647 if (Ustrcmp(CS da->address, ip) == 0) break;
2650 /* Handle bitmask matching */
2656 /* At present, all known DNS blocking lists use A records, with
2657 IPv4 addresses on the RHS encoding the information they return. I
2658 wonder if this will linger on as the last vestige of IPv4 when IPv6
2659 is ubiquitous? Anyway, for now we use paranoia code to completely
2660 ignore IPv6 addresses. The default mask is 0, which always matches.
2661 We change this only for IPv4 addresses in the list. */
2663 if (host_aton(ip, address) == 1) mask = address[0];
2665 /* Scan the returned addresses, skipping any that are IPv6 */
2667 for (da = cb->rhs; da != NULL; da = da->next)
2669 if (host_aton(da->address, address) != 1) continue;
2670 if ((address[0] & mask) == mask) break;
2674 /* Break out if a match has been found */
2676 if (da != NULL) break;
2681 (a) No IP address in a positive list matched, or
2682 (b) An IP address in a negative list did match
2684 then behave as if the DNSBL lookup had not succeeded, i.e. the host is
2687 if (invert_result != (da == NULL))
2691 debug_printf("=> but we are not accepting this block class because\n");
2692 debug_printf("=> there was %s match for %c%s\n",
2693 invert_result? "an exclude":"no", bitmask? '&' : '=', iplist);
2699 /* Either there was no IP list, or the record matched, implying that the
2700 domain is on the list. We now want to find a corresponding TXT record. If an
2701 alternate domain is specified for the TXT record, call this function
2702 recursively to look that up; this has the side effect of re-checking that
2703 there is indeed an A record at the alternate domain. */
2705 if (domain_txt != domain)
2706 return one_check_dnsbl(domain_txt, domain_txt, keydomain, prepend, NULL,
2707 FALSE, invert_result, defer_return);
2709 /* If there is no alternate domain, look up a TXT record in the main domain
2710 if it has not previously been cached. */
2714 cb->text_set = TRUE;
2715 if (dns_basic_lookup(&dnsa, query, T_TXT) == DNS_SUCCEED)
2718 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2720 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
2721 if (rr->type == T_TXT) break;
2724 int len = (rr->data)[0];
2725 if (len > 511) len = 127;
2726 store_pool = POOL_PERM;
2727 cb->text = string_sprintf("%.*s", len, (const uschar *)(rr->data+1));
2728 store_pool = old_pool;
2733 dnslist_value = addlist;
2734 dnslist_text = cb->text;
2738 /* There was a problem with the DNS lookup */
2740 if (cb->rc != DNS_NOMATCH && cb->rc != DNS_NODATA)
2742 log_write(L_dnslist_defer, LOG_MAIN,
2743 "DNS list lookup defer (probably timeout) for %s: %s", query,
2744 (defer_return == OK)? US"assumed in list" :
2745 (defer_return == FAIL)? US"assumed not in list" :
2746 US"returned DEFER");
2747 return defer_return;
2750 /* No entry was found in the DNS; continue for next domain */
2754 debug_printf("DNS lookup for %s failed\n", query);
2755 debug_printf("=> that means %s is not listed at %s\n",
2765 /*************************************************
2766 * Check host against DNS black lists *
2767 *************************************************/
2769 /* This function runs checks against a list of DNS black lists, until one
2770 matches. Each item on the list can be of the form
2772 domain=ip-address/key
2774 The domain is the right-most domain that is used for the query, for example,
2775 blackholes.mail-abuse.org. If the IP address is present, there is a match only
2776 if the DNS lookup returns a matching IP address. Several addresses may be
2777 given, comma-separated, for example: x.y.z=127.0.0.1,127.0.0.2.
2779 If no key is given, what is looked up in the domain is the inverted IP address
2780 of the current client host. If a key is given, it is used to construct the
2781 domain for the lookup. For example:
2783 dsn.rfc-ignorant.org/$sender_address_domain
2785 After finding a match in the DNS, the domain is placed in $dnslist_domain, and
2786 then we check for a TXT record for an error message, and if found, save its
2787 value in $dnslist_text. We also cache everything in a tree, to optimize
2790 The TXT record is normally looked up in the same domain as the A record, but
2791 when many lists are combined in a single DNS domain, this will not be a very
2792 specific message. It is possible to specify a different domain for looking up
2793 TXT records; this is given before the main domain, comma-separated. For
2796 dnslists = http.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.2 : \
2797 socks.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.3
2799 The caching ensures that only one lookup in dnsbl.sorbs.net is done.
2801 Note: an address for testing RBL is 192.203.178.39
2802 Note: an address for testing DUL is 192.203.178.4
2803 Note: a domain for testing RFCI is example.tld.dsn.rfc-ignorant.org
2806 listptr the domain/address/data list
2808 Returns: OK successful lookup (i.e. the address is on the list), or
2809 lookup deferred after +include_unknown
2810 FAIL name not found, or no data found for the given type, or
2811 lookup deferred after +exclude_unknown (default)
2812 DEFER lookup failure, if +defer_unknown was set
2816 verify_check_dnsbl(uschar **listptr)
2819 int defer_return = FAIL;
2820 BOOL invert_result = FALSE;
2821 uschar *list = *listptr;
2824 uschar buffer[1024];
2825 uschar revadd[128]; /* Long enough for IPv6 address */
2827 /* Indicate that the inverted IP address is not yet set up */
2831 /* In case this is the first time the DNS resolver is being used. */
2833 dns_init(FALSE, FALSE);
2835 /* Loop through all the domains supplied, until something matches */
2837 while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
2840 BOOL bitmask = FALSE;
2846 HDEBUG(D_dnsbl) debug_printf("DNS list check: %s\n", domain);
2848 /* Deal with special values that change the behaviour on defer */
2850 if (domain[0] == '+')
2852 if (strcmpic(domain, US"+include_unknown") == 0) defer_return = OK;
2853 else if (strcmpic(domain, US"+exclude_unknown") == 0) defer_return = FAIL;
2854 else if (strcmpic(domain, US"+defer_unknown") == 0) defer_return = DEFER;
2856 log_write(0, LOG_MAIN|LOG_PANIC, "unknown item in dnslist (ignored): %s",
2861 /* See if there's explicit data to be looked up */
2863 key = Ustrchr(domain, '/');
2864 if (key != NULL) *key++ = 0;
2866 /* See if there's a list of addresses supplied after the domain name. This is
2867 introduced by an = or a & character; if preceded by ! we invert the result.
2870 iplist = Ustrchr(domain, '=');
2874 iplist = Ustrchr(domain, '&');
2879 if (iplist > domain && iplist[-1] == '!')
2881 invert_result = TRUE;
2887 /* If there is a comma in the domain, it indicates that a second domain for
2888 looking up TXT records is provided, before the main domain. Otherwise we must
2889 set domain_txt == domain. */
2891 domain_txt = domain;
2892 comma = Ustrchr(domain, ',');
2899 /* Check that what we have left is a sensible domain name. There is no reason
2900 why these domains should in fact use the same syntax as hosts and email
2901 domains, but in practice they seem to. However, there is little point in
2902 actually causing an error here, because that would no doubt hold up incoming
2903 mail. Instead, I'll just log it. */
2905 for (s = domain; *s != 0; s++)
2907 if (!isalnum(*s) && *s != '-' && *s != '.')
2909 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
2910 "strange characters - is this right?", domain);
2915 /* Check the alternate domain if present */
2917 if (domain_txt != domain) for (s = domain_txt; *s != 0; s++)
2919 if (!isalnum(*s) && *s != '-' && *s != '.')
2921 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
2922 "strange characters - is this right?", domain_txt);
2927 /* If there is no key string, construct the query by adding the domain name
2928 onto the inverted host address, and perform a single DNS lookup. */
2932 if (sender_host_address == NULL) return FAIL; /* can never match */
2933 if (revadd[0] == 0) invert_address(revadd, sender_host_address);
2934 rc = one_check_dnsbl(domain, domain_txt, sender_host_address, revadd,
2935 iplist, bitmask, invert_result, defer_return);
2938 dnslist_domain = string_copy(domain_txt);
2939 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
2940 sender_host_address, dnslist_domain);
2942 if (rc != FAIL) return rc; /* OK or DEFER */
2945 /* If there is a key string, it can be a list of domains or IP addresses to
2946 be concatenated with the main domain. */
2953 uschar keybuffer[256];
2954 uschar keyrevadd[128];
2956 while ((keydomain = string_nextinlist(&key, &keysep, keybuffer,
2957 sizeof(keybuffer))) != NULL)
2959 uschar *prepend = keydomain;
2961 if (string_is_ip_address(keydomain, NULL) != 0)
2963 invert_address(keyrevadd, keydomain);
2964 prepend = keyrevadd;
2967 rc = one_check_dnsbl(domain, domain_txt, keydomain, prepend, iplist,
2968 bitmask, invert_result, defer_return);
2972 dnslist_domain = string_copy(domain_txt);
2973 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
2974 keydomain, dnslist_domain);
2978 /* If the lookup deferred, remember this fact. We keep trying the rest
2979 of the list to see if we get a useful result, and if we don't, we return
2980 DEFER at the end. */
2982 if (rc == DEFER) defer = TRUE;
2983 } /* continue with next keystring domain/address */
2985 if (defer) return DEFER;
2987 } /* continue with next dnsdb outer domain */
2992 /* End of verify.c */