1 /* $Cambridge: exim/src/src/verify.c,v 1.19 2005/06/17 10:20:30 ph10 Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2005 */
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;
153 uschar *from_address;
154 uschar *random_local_part = NULL;
155 uschar **failure_ptr = is_recipient?
156 &recipient_verify_failure : &sender_verify_failure;
158 open_db *dbm_file = NULL;
159 dbdata_callout_cache new_domain_record;
160 dbdata_callout_cache_address new_address_record;
162 time_t callout_start_time;
164 new_domain_record.result = ccache_unknown;
165 new_domain_record.postmaster_result = ccache_unknown;
166 new_domain_record.random_result = ccache_unknown;
168 memset(&new_address_record, 0, sizeof(new_address_record));
170 /* For a recipient callout, the key used for the address cache record must
171 include the sender address if we are using the real sender in the callout,
172 because that may influence the result of the callout. */
174 address_key = addr->address;
179 if ((options & vopt_callout_recipsender) != 0)
181 address_key = string_sprintf("%s/<%s>", addr->address, sender_address);
182 from_address = sender_address;
184 else if ((options & vopt_callout_recippmaster) != 0)
186 address_key = string_sprintf("%s/<postmaster@%s>", addr->address,
187 qualify_domain_sender);
188 from_address = string_sprintf("postmaster@%s", qualify_domain_sender);
192 /* For a sender callout, we must adjust the key if the mailfrom address is not
197 from_address = (se_mailfrom == NULL)? US"" : se_mailfrom;
198 if (from_address[0] != 0)
199 address_key = string_sprintf("%s/<%s>", addr->address, from_address);
202 /* Open the callout cache database, it it exists, for reading only at this
203 stage, unless caching has been disabled. */
205 if (callout_no_cache)
207 HDEBUG(D_verify) debug_printf("callout cache: disabled by no_cache\n");
209 else if ((dbm_file = dbfn_open(US"callout", O_RDWR, &dbblock, FALSE)) == NULL)
211 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
214 /* If a cache database is available see if we can avoid the need to do an
215 actual callout by making use of previously-obtained data. */
217 if (dbm_file != NULL)
219 dbdata_callout_cache_address *cache_address_record;
220 dbdata_callout_cache *cache_record = get_callout_cache_record(dbm_file,
221 addr->domain, US"domain",
222 callout_cache_domain_positive_expire,
223 callout_cache_domain_negative_expire);
225 /* If an unexpired cache record was found for this domain, see if the callout
226 process can be short-circuited. */
228 if (cache_record != NULL)
230 /* If an early command (up to and including MAIL FROM:<>) was rejected,
231 there is no point carrying on. The callout fails. */
233 if (cache_record->result == ccache_reject)
235 setflag(addr, af_verify_nsfail);
237 debug_printf("callout cache: domain gave initial rejection, or "
238 "does not accept HELO or MAIL FROM:<>\n");
239 setflag(addr, af_verify_nsfail);
240 addr->user_message = US"(result of an earlier callout reused).";
242 *failure_ptr = US"mail";
246 /* If a previous check on a "random" local part was accepted, we assume
247 that the server does not do any checking on local parts. There is therefore
248 no point in doing the callout, because it will always be successful. If a
249 random check previously failed, arrange not to do it again, but preserve
250 the data in the new record. If a random check is required but hasn't been
251 done, skip the remaining cache processing. */
253 if (callout_random) switch(cache_record->random_result)
257 debug_printf("callout cache: domain accepts random addresses\n");
258 goto END_CALLOUT; /* Default yield is OK */
262 debug_printf("callout cache: domain rejects random addresses\n");
263 callout_random = FALSE;
264 new_domain_record.random_result = ccache_reject;
265 new_domain_record.random_stamp = cache_record->random_stamp;
270 debug_printf("callout cache: need to check random address handling "
271 "(not cached or cache expired)\n");
275 /* If a postmaster check is requested, but there was a previous failure,
276 there is again no point in carrying on. If a postmaster check is required,
277 but has not been done before, we are going to have to do a callout, so skip
278 remaining cache processing. */
280 if (pm_mailfrom != NULL)
282 if (cache_record->postmaster_result == ccache_reject)
284 setflag(addr, af_verify_pmfail);
286 debug_printf("callout cache: domain does not accept "
287 "RCPT TO:<postmaster@domain>\n");
289 *failure_ptr = US"postmaster";
290 setflag(addr, af_verify_pmfail);
291 addr->user_message = US"(result of earlier verification reused).";
294 if (cache_record->postmaster_result == ccache_unknown)
297 debug_printf("callout cache: need to check RCPT "
298 "TO:<postmaster@domain> (not cached or cache expired)\n");
302 /* If cache says OK, set pm_mailfrom NULL to prevent a redundant
303 postmaster check if the address itself has to be checked. Also ensure
304 that the value in the cache record is preserved (with its old timestamp).
307 HDEBUG(D_verify) debug_printf("callout cache: domain accepts RCPT "
308 "TO:<postmaster@domain>\n");
310 new_domain_record.postmaster_result = ccache_accept;
311 new_domain_record.postmaster_stamp = cache_record->postmaster_stamp;
315 /* We can't give a result based on information about the domain. See if there
316 is an unexpired cache record for this specific address (combined with the
317 sender address if we are doing a recipient callout with a non-empty sender).
320 cache_address_record = (dbdata_callout_cache_address *)
321 get_callout_cache_record(dbm_file,
322 address_key, US"address",
323 callout_cache_positive_expire,
324 callout_cache_negative_expire);
326 if (cache_address_record != NULL)
328 if (cache_address_record->result == ccache_accept)
331 debug_printf("callout cache: address record is positive\n");
336 debug_printf("callout cache: address record is negative\n");
337 addr->user_message = US"Previous (cached) callout verification failure";
338 *failure_ptr = US"recipient";
344 /* Close the cache database while we actually do the callout for real. */
347 dbfn_close(dbm_file);
351 /* The information wasn't available in the cache, so we have to do a real
352 callout and save the result in the cache for next time, unless no_cache is set,
353 or unless we have a previously cached negative random result. If we are to test
354 with a random local part, ensure that such a local part is available. If not,
355 log the fact, but carry on without randomming. */
357 if (callout_random && callout_random_local_part != NULL)
359 random_local_part = expand_string(callout_random_local_part);
360 if (random_local_part == NULL)
361 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand "
362 "callout_random_local_part: %s", expand_string_message);
365 /* Default the connect and overall callout timeouts if not set, and record the
366 time we are starting so that we can enforce it. */
368 if (callout_overall < 0) callout_overall = 4 * callout;
369 if (callout_connect < 0) callout_connect = callout;
370 callout_start_time = time(NULL);
372 /* Now make connections to the hosts and do real callouts. The list of hosts
373 is passed in as an argument. */
375 for (host = host_list; host != NULL && !done; host = host->next)
377 smtp_inblock inblock;
378 smtp_outblock outblock;
381 BOOL send_quit = TRUE;
382 uschar *helo = US"HELO";
383 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
384 uschar inbuffer[4096];
385 uschar outbuffer[1024];
386 uschar responsebuffer[4096];
388 clearflag(addr, af_verify_pmfail); /* postmaster callout flag */
389 clearflag(addr, af_verify_nsfail); /* null sender callout flag */
391 /* Skip this host if we don't have an IP address for it. */
393 if (host->address == NULL)
395 DEBUG(D_verify) debug_printf("no IP address for host name %s: skipping\n",
400 /* Check the overall callout timeout */
402 if (time(NULL) - callout_start_time >= callout_overall)
404 HDEBUG(D_verify) debug_printf("overall timeout for callout exceeded\n");
408 /* Set IPv4 or IPv6 */
410 host_af = (Ustrchr(host->address, ':') == NULL)? AF_INET:AF_INET6;
412 /* Expand and interpret the interface and port strings. This has to
413 be delayed till now, because they may expand differently for different
414 hosts. If there's a failure, log it, but carry on with the defaults. */
416 deliver_host = host->name;
417 deliver_host_address = host->address;
418 if (!smtp_get_interface(tf->interface, host_af, addr, NULL, &interface,
420 !smtp_get_port(tf->port, addr, &port, US"callout"))
421 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
423 deliver_host = deliver_host_address = NULL;
425 /* Set HELO string according to the protocol */
427 if (Ustrcmp(tf->protocol, "lmtp") == 0) helo = US"LHLO";
429 HDEBUG(D_verify) debug_printf("interface=%s port=%d\n", interface, port);
431 /* Set up the buffer for reading SMTP response packets. */
433 inblock.buffer = inbuffer;
434 inblock.buffersize = sizeof(inbuffer);
435 inblock.ptr = inbuffer;
436 inblock.ptrend = inbuffer;
438 /* Set up the buffer for holding SMTP commands while pipelining */
440 outblock.buffer = outbuffer;
441 outblock.buffersize = sizeof(outbuffer);
442 outblock.ptr = outbuffer;
443 outblock.cmd_count = 0;
444 outblock.authenticating = FALSE;
446 /* Connect to the host; on failure, just loop for the next one, but we
447 set the error for the last one. Use the callout_connect timeout. */
449 inblock.sock = outblock.sock =
450 smtp_connect(host, host_af, port, interface, callout_connect, TRUE);
451 if (inblock.sock < 0)
453 addr->message = string_sprintf("could not connect to %s [%s]: %s",
454 host->name, host->address, strerror(errno));
458 /* Wait for initial response, and then run the initial SMTP commands. The
459 smtp_write_command() function leaves its command in big_buffer. This is
460 used in error responses. Initialize it in case the connection is
463 Ustrcpy(big_buffer, "initial connection");
466 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
469 smtp_write_command(&outblock, FALSE, "%s %s\r\n", helo,
470 smtp_active_hostname) >= 0 &&
471 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
474 smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>\r\n",
475 from_address) >= 0 &&
476 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
479 /* If the host gave an initial error, or does not accept HELO or MAIL
480 FROM:<>, arrange to cache this information, but don't record anything for an
481 I/O error or a defer. Do not cache rejections when a non-empty sender has
482 been used, because that blocks the whole domain for all senders. */
486 *failure_ptr = US"mail";
487 if (errno == 0 && responsebuffer[0] == '5')
489 setflag(addr, af_verify_nsfail);
490 if (from_address[0] == 0) new_domain_record.result = ccache_reject;
494 /* Otherwise, proceed to check a "random" address (if required), then the
495 given address, and the postmaster address (if required). Between each check,
496 issue RSET, because some servers accept only one recipient after MAIL
501 new_domain_record.result = ccache_accept;
503 /* Do the random local part check first */
505 if (random_local_part != NULL)
507 uschar randombuffer[1024];
509 smtp_write_command(&outblock, FALSE,
510 "RCPT TO:<%.1000s@%.1000s>\r\n", random_local_part,
511 addr->domain) >= 0 &&
512 smtp_read_response(&inblock, randombuffer,
513 sizeof(randombuffer), '2', callout);
515 /* Remember when we last did a random test */
517 new_domain_record.random_stamp = time(NULL);
519 /* If accepted, we aren't going to do any further tests below. */
523 new_domain_record.random_result = ccache_accept;
526 /* Otherwise, cache a real negative response, and get back to the right
527 state to send RCPT. Unless there's some problem such as a dropped
528 connection, we expect to succeed, because the commands succeeded above. */
532 if (randombuffer[0] == '5')
533 new_domain_record.random_result = ccache_reject;
536 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
537 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
540 smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>\r\n",
541 from_address) >= 0 &&
542 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
545 else done = FALSE; /* Some timeout/connection problem */
548 /* If the host is accepting all local parts, as determined by the "random"
549 check, we don't need to waste time doing any further checking. */
551 if (new_domain_record.random_result != ccache_accept && done)
554 smtp_write_command(&outblock, FALSE, "RCPT TO:<%.1000s>\r\n",
555 transport_rcpt_address(addr,
556 addr->transport->rcpt_include_affixes)) >= 0 &&
557 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
561 new_address_record.result = ccache_accept;
562 else if (errno == 0 && responsebuffer[0] == '5')
564 *failure_ptr = US"recipient";
565 new_address_record.result = ccache_reject;
568 /* Do postmaster check if requested; if a full check is required, we
569 check for RCPT TO:<postmaster> (no domain) in accordance with RFC 821. */
571 if (done && pm_mailfrom != NULL)
574 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
575 smtp_read_response(&inblock, responsebuffer,
576 sizeof(responsebuffer), '2', callout) &&
578 smtp_write_command(&outblock, FALSE,
579 "MAIL FROM:<%s>\r\n", pm_mailfrom) >= 0 &&
580 smtp_read_response(&inblock, responsebuffer,
581 sizeof(responsebuffer), '2', callout) &&
583 /* First try using the current domain */
586 smtp_write_command(&outblock, FALSE,
587 "RCPT TO:<postmaster@%.1000s>\r\n", addr->domain) >= 0 &&
588 smtp_read_response(&inblock, responsebuffer,
589 sizeof(responsebuffer), '2', callout)
594 /* If that doesn't work, and a full check is requested,
595 try without the domain. */
598 (options & vopt_callout_fullpm) != 0 &&
599 smtp_write_command(&outblock, FALSE,
600 "RCPT TO:<postmaster>\r\n") >= 0 &&
601 smtp_read_response(&inblock, responsebuffer,
602 sizeof(responsebuffer), '2', callout)
605 /* Sort out the cache record */
607 new_domain_record.postmaster_stamp = time(NULL);
610 new_domain_record.postmaster_result = ccache_accept;
611 else if (errno == 0 && responsebuffer[0] == '5')
613 *failure_ptr = US"postmaster";
614 setflag(addr, af_verify_pmfail);
615 new_domain_record.postmaster_result = ccache_reject;
618 } /* Random not accepted */
619 } /* MAIL FROM: accepted */
621 /* For any failure of the main check, other than a negative response, we just
622 close the connection and carry on. We can identify a negative response by the
623 fact that errno is zero. For I/O errors it will be non-zero
625 Set up different error texts for logging and for sending back to the caller
626 as an SMTP response. Log in all cases, using a one-line format. For sender
627 callouts, give a full response to the caller, but for recipient callouts,
628 don't give the IP address because this may be an internal host whose identity
629 is not to be widely broadcast. */
633 if (errno == ETIMEDOUT)
635 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
640 if (*responsebuffer == 0) Ustrcpy(responsebuffer, US"connection dropped");
643 string_sprintf("response to \"%s\" from %s [%s] was: %s",
644 big_buffer, host->name, host->address,
645 string_printing(responsebuffer));
647 addr->user_message = is_recipient?
648 string_sprintf("Callout verification failed:\n%s", responsebuffer)
650 string_sprintf("Called: %s\nSent: %s\nResponse: %s",
651 host->address, big_buffer, responsebuffer);
653 /* Hard rejection ends the process */
655 if (responsebuffer[0] == '5') /* Address rejected */
663 /* End the SMTP conversation and close the connection. */
665 if (send_quit) (void)smtp_write_command(&outblock, FALSE, "QUIT\r\n");
667 } /* Loop through all hosts, while !done */
669 /* If we get here with done == TRUE, a successful callout happened, and yield
670 will be set OK or FAIL according to the response to the RCPT command.
671 Otherwise, we looped through the hosts but couldn't complete the business.
672 However, there may be domain-specific information to cache in both cases.
674 The value of the result field in the new_domain record is ccache_unknown if
675 there was an error before or with MAIL FROM:, and errno was not zero,
676 implying some kind of I/O error. We don't want to write the cache in that case.
677 Otherwise the value is ccache_accept or ccache_reject. */
679 if (!callout_no_cache && new_domain_record.result != ccache_unknown)
681 if ((dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE))
684 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
688 (void)dbfn_write(dbm_file, addr->domain, &new_domain_record,
689 (int)sizeof(dbdata_callout_cache));
690 HDEBUG(D_verify) debug_printf("wrote callout cache domain record:\n"
691 " result=%d postmaster=%d random=%d\n",
692 new_domain_record.result,
693 new_domain_record.postmaster_result,
694 new_domain_record.random_result);
698 /* If a definite result was obtained for the callout, cache it unless caching
703 if (!callout_no_cache && new_address_record.result != ccache_unknown)
705 if (dbm_file == NULL)
706 dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE);
707 if (dbm_file == NULL)
709 HDEBUG(D_verify) debug_printf("no callout cache available\n");
713 (void)dbfn_write(dbm_file, address_key, &new_address_record,
714 (int)sizeof(dbdata_callout_cache_address));
715 HDEBUG(D_verify) debug_printf("wrote %s callout cache address record\n",
716 (new_address_record.result == ccache_accept)? "positive" : "negative");
721 /* Failure to connect to any host, or any response other than 2xx or 5xx is a
722 temporary error. If there was only one host, and a response was received, leave
723 it alone if supplying details. Otherwise, give a generic response. */
727 uschar *dullmsg = string_sprintf("Could not complete %s verify callout",
728 is_recipient? "recipient" : "sender");
731 if (host_list->next != NULL || addr->message == NULL) addr->message = dullmsg;
733 addr->user_message = (!smtp_return_error_details)? dullmsg :
734 string_sprintf("%s for <%s>.\n"
735 "The mail server(s) for the domain may be temporarily unreachable, or\n"
736 "they may be permanently unreachable from this server. In the latter case,\n%s",
737 dullmsg, addr->address,
739 "the address will never be accepted."
741 "you need to change the address or create an MX record for its domain\n"
742 "if it is supposed to be generally accessible from the Internet.\n"
743 "Talk to your mail administrator for details.");
745 /* Force a specific error code */
747 addr->basic_errno = ERRNO_CALLOUTDEFER;
750 /* Come here from within the cache-reading code on fast-track exit. */
753 if (dbm_file != NULL) dbfn_close(dbm_file);
759 /*************************************************
760 * Copy error to toplevel address *
761 *************************************************/
763 /* This function is used when a verify fails or defers, to ensure that the
764 failure or defer information is in the original toplevel address. This applies
765 when an address is redirected to a single new address, and the failure or
766 deferral happens to the child address.
769 vaddr the verify address item
770 addr the final address item
773 Returns: the value of YIELD
777 copy_error(address_item *vaddr, address_item *addr, int yield)
781 vaddr->message = addr->message;
782 vaddr->user_message = addr->user_message;
783 vaddr->basic_errno = addr->basic_errno;
784 vaddr->more_errno = addr->more_errno;
792 /*************************************************
793 * Verify an email address *
794 *************************************************/
796 /* This function is used both for verification (-bv and at other times) and
797 address testing (-bt), which is indicated by address_test_mode being set.
800 vaddr contains the address to verify; the next field in this block
802 f if not NULL, write the result to this file
803 options various option bits:
804 vopt_fake_sender => this sender verify is not for the real
805 sender (it was verify=sender=xxxx or an address from a
806 header line) - rewriting must not change sender_address
807 vopt_is_recipient => this is a recipient address, otherwise
808 it's a sender address - this affects qualification and
809 rewriting and messages from callouts
810 vopt_qualify => qualify an unqualified address; else error
811 vopt_expn => called from SMTP EXPN command
813 These ones are used by do_callout() -- the options variable
816 vopt_callout_fullpm => if postmaster check, do full one
817 vopt_callout_no_cache => don't use callout cache
818 vopt_callout_random => do the "random" thing
819 vopt_callout_recipsender => use real sender for recipient
820 vopt_callout_recippmaster => use postmaster for recipient
822 callout if > 0, specifies that callout is required, and gives timeout
823 for individual commands
824 callout_overall if > 0, gives overall timeout for the callout function;
825 if < 0, a default is used (see do_callout())
826 callout_connect the connection timeout for callouts
827 se_mailfrom when callout is requested to verify a sender, use this
828 in MAIL FROM; NULL => ""
829 pm_mailfrom when callout is requested, if non-NULL, do the postmaster
830 thing and use this as the sender address (may be "")
832 routed if not NULL, set TRUE if routing succeeded, so we can
833 distinguish between routing failed and callout failed
835 Returns: OK address verified
836 FAIL address failed to verify
837 DEFER can't tell at present
841 verify_address(address_item *vaddr, FILE *f, int options, int callout,
842 int callout_overall, int callout_connect, uschar *se_mailfrom,
843 uschar *pm_mailfrom, BOOL *routed)
846 BOOL full_info = (f == NULL)? FALSE : (debug_selector != 0);
847 BOOL is_recipient = (options & vopt_is_recipient) != 0;
848 BOOL expn = (options & vopt_expn) != 0;
851 int verify_type = expn? v_expn :
852 address_test_mode? v_none :
853 is_recipient? v_recipient : v_sender;
854 address_item *addr_list;
855 address_item *addr_new = NULL;
856 address_item *addr_remote = NULL;
857 address_item *addr_local = NULL;
858 address_item *addr_succeed = NULL;
859 uschar **failure_ptr = is_recipient?
860 &recipient_verify_failure : &sender_verify_failure;
861 uschar *ko_prefix, *cr;
862 uschar *address = vaddr->address;
864 uschar null_sender[] = { 0 }; /* Ensure writeable memory */
866 /* Clear, just in case */
870 /* Set up a prefix and suffix for error message which allow us to use the same
871 output statements both in EXPN mode (where an SMTP response is needed) and when
872 debugging with an output file. */
876 ko_prefix = US"553 ";
879 else ko_prefix = cr = US"";
881 /* Add qualify domain if permitted; otherwise an unqualified address fails. */
883 if (parse_find_at(address) == NULL)
885 if ((options & vopt_qualify) == 0)
888 fprintf(f, "%sA domain is required for \"%s\"%s\n", ko_prefix, address,
890 *failure_ptr = US"qualify";
893 address = rewrite_address_qualify(address, is_recipient);
898 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
899 debug_printf("%s %s\n", address_test_mode? "Testing" : "Verifying", address);
902 /* Rewrite and report on it. Clear the domain and local part caches - these
903 may have been set by domains and local part tests during an ACL. */
905 if (global_rewrite_rules != NULL)
907 uschar *old = address;
908 address = rewrite_address(address, is_recipient, FALSE,
909 global_rewrite_rules, rewrite_existflags);
912 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->localpart_cache[i] = 0;
913 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->domain_cache[i] = 0;
914 if (f != NULL && !expn) fprintf(f, "Address rewritten as: %s\n", address);
918 /* If this is the real sender address, we must update sender_address at
919 this point, because it may be referred to in the routers. */
921 if ((options & (vopt_fake_sender|vopt_is_recipient)) == 0)
922 sender_address = address;
924 /* If the address was rewritten to <> no verification can be done, and we have
925 to return OK. This rewriting is permitted only for sender addresses; for other
926 addresses, such rewriting fails. */
928 if (address[0] == 0) return OK;
930 /* Save a copy of the sender address for re-instating if we change it to <>
931 while verifying a sender address (a nice bit of self-reference there). */
933 save_sender = sender_address;
935 /* Update the address structure with the possibly qualified and rewritten
936 address. Set it up as the starting address on the chain of new addresses. */
938 vaddr->address = address;
941 /* We need a loop, because an address can generate new addresses. We must also
942 cope with generated pipes and files at the top level. (See also the code and
943 comment in deliver.c.) However, it is usually the case that the router for
944 user's .forward files has its verify flag turned off.
946 If an address generates more than one child, the loop is used only when
947 full_info is set, and this can only be set locally. Remote enquiries just get
948 information about the top level address, not anything that it generated. */
950 while (addr_new != NULL)
953 address_item *addr = addr_new;
955 addr_new = addr->next;
960 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
961 debug_printf("Considering %s\n", addr->address);
964 /* Handle generated pipe, file or reply addresses. We don't get these
965 when handling EXPN, as it does only one level of expansion. */
967 if (testflag(addr, af_pfr))
974 if (addr->address[0] == '>')
976 allow = testflag(addr, af_allow_reply);
977 fprintf(f, "%s -> mail %s", addr->parent->address, addr->address + 1);
981 allow = (addr->address[0] == '|')?
982 testflag(addr, af_allow_pipe) : testflag(addr, af_allow_file);
983 fprintf(f, "%s -> %s", addr->parent->address, addr->address);
986 if (addr->basic_errno == ERRNO_BADTRANSPORT)
987 fprintf(f, "\n*** Error in setting up pipe, file, or autoreply:\n"
988 "%s\n", addr->message);
990 fprintf(f, "\n transport = %s\n", addr->transport->name);
992 fprintf(f, " *** forbidden ***\n");
997 /* Just in case some router parameter refers to it. */
999 return_path = (addr->p.errors_address != NULL)?
1000 addr->p.errors_address : sender_address;
1002 /* Split the address into domain and local part, handling the %-hack if
1003 necessary, and then route it. While routing a sender address, set
1004 $sender_address to <> because that is what it will be if we were trying to
1005 send a bounce to the sender. */
1007 if (routed != NULL) *routed = FALSE;
1008 if ((rc = deliver_split_address(addr)) == OK)
1010 if (!is_recipient) sender_address = null_sender;
1011 rc = route_address(addr, &addr_local, &addr_remote, &addr_new,
1012 &addr_succeed, verify_type);
1013 sender_address = save_sender; /* Put back the real sender */
1016 /* If routing an address succeeded, set the flag that remembers, for use when
1017 an ACL cached a sender verify (in case a callout fails). Then if routing set
1018 up a list of hosts or the transport has a host list, and the callout option
1019 is set, and we aren't in a host checking run, do the callout verification,
1020 and set another flag that notes that a callout happened. */
1024 if (routed != NULL) *routed = TRUE;
1027 host_item *host_list = addr->host_list;
1029 /* Default, if no remote transport, to NULL for the interface (=> any),
1030 "smtp" for the port, and "smtp" for the protocol. */
1032 transport_feedback tf = { NULL, US"smtp", US"smtp", NULL, FALSE, FALSE };
1034 /* If verification yielded a remote transport, we want to use that
1035 transport's options, so as to mimic what would happen if we were really
1036 sending a message to this address. */
1038 if (addr->transport != NULL && !addr->transport->info->local)
1040 (void)(addr->transport->setup)(addr->transport, addr, &tf, NULL);
1042 /* If the transport has hosts and the router does not, or if the
1043 transport is configured to override the router's hosts, we must build a
1044 host list of the transport's hosts, and find the IP addresses */
1046 if (tf.hosts != NULL && (host_list == NULL || tf.hosts_override))
1050 host_list = NULL; /* Ignore the router's hosts */
1052 deliver_domain = addr->domain;
1053 deliver_localpart = addr->local_part;
1054 s = expand_string(tf.hosts);
1055 deliver_domain = deliver_localpart = NULL;
1059 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand list of hosts "
1060 "\"%s\" in %s transport for callout: %s", tf.hosts,
1061 addr->transport->name, expand_string_message);
1065 uschar *canonical_name;
1066 host_item *host, *nexthost;
1067 host_build_hostlist(&host_list, s, tf.hosts_randomize);
1069 /* Just ignore failures to find a host address. If we don't manage
1070 to find any addresses, the callout will defer. Note that more than
1071 one address may be found for a single host, which will result in
1072 additional host items being inserted into the chain. Hence we must
1073 save the next host first. */
1075 for (host = host_list; host != NULL; host = nexthost)
1077 nexthost = host->next;
1078 if (tf.gethostbyname ||
1079 string_is_ip_address(host->name, NULL) > 0)
1080 (void)host_find_byname(host, NULL, &canonical_name, TRUE);
1083 int flags = HOST_FIND_BY_A;
1084 if (tf.qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
1085 if (tf.search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
1086 (void)host_find_bydns(host, NULL, flags, NULL, NULL, NULL,
1087 &canonical_name, NULL);
1094 /* Can only do a callout if we have at least one host! If the callout
1095 fails, it will have set ${sender,recipient}_verify_failure. */
1097 if (host_list != NULL)
1099 HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n");
1100 if (host_checking && !host_checking_callout)
1103 debug_printf("... callout omitted by default when host testing\n"
1104 "(Use -bhc if you want the callouts to happen.)\n");
1108 rc = do_callout(addr, host_list, &tf, callout, callout_overall,
1109 callout_connect, options, se_mailfrom, pm_mailfrom);
1114 HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor "
1115 "transport provided a host list\n");
1120 /* Otherwise, any failure is a routing failure */
1122 else *failure_ptr = US"route";
1124 /* A router may return REROUTED if it has set up a child address as a result
1125 of a change of domain name (typically from widening). In this case we always
1126 want to continue to verify the new child. */
1128 if (rc == REROUTED) continue;
1130 /* Handle hard failures */
1137 fprintf(f, "%s%s %s", ko_prefix, address,
1138 address_test_mode? "is undeliverable" : "failed to verify");
1139 if (!expn && admin_user)
1141 if (addr->basic_errno > 0)
1142 fprintf(f, ": %s", strerror(addr->basic_errno));
1143 if (addr->message != NULL)
1144 fprintf(f, ":\n %s", addr->message);
1146 fprintf(f, "%s\n", cr);
1149 if (!full_info) return copy_error(vaddr, addr, FAIL);
1155 else if (rc == DEFER)
1160 fprintf(f, "%s%s cannot be resolved at this time", ko_prefix, address);
1161 if (!expn && admin_user)
1163 if (addr->basic_errno > 0)
1164 fprintf(f, ":\n %s", strerror(addr->basic_errno));
1165 if (addr->message != NULL)
1166 fprintf(f, ":\n %s", addr->message);
1167 else if (addr->basic_errno <= 0)
1168 fprintf(f, ":\n unknown error");
1171 fprintf(f, "%s\n", cr);
1173 if (!full_info) return copy_error(vaddr, addr, DEFER);
1174 else if (yield == OK) yield = DEFER;
1177 /* If we are handling EXPN, we do not want to continue to route beyond
1182 uschar *ok_prefix = US"250-";
1183 if (addr_new == NULL)
1185 if (addr_local == NULL && addr_remote == NULL)
1186 fprintf(f, "250 mail to <%s> is discarded\r\n", address);
1188 fprintf(f, "250 <%s>\r\n", address);
1190 else while (addr_new != NULL)
1192 address_item *addr2 = addr_new;
1193 addr_new = addr2->next;
1194 if (addr_new == NULL) ok_prefix = US"250 ";
1195 fprintf(f, "%s<%s>\r\n", ok_prefix, addr2->address);
1200 /* Successful routing other than EXPN. */
1204 /* Handle successful routing when short info wanted. Otherwise continue for
1205 other (generated) addresses. Short info is the operational case. Full info
1206 can be requested only when debug_selector != 0 and a file is supplied.
1208 There is a conflict between the use of aliasing as an alternate email
1209 address, and as a sort of mailing list. If an alias turns the incoming
1210 address into just one address (e.g. J.Caesar->jc44) you may well want to
1211 carry on verifying the generated address to ensure it is valid when
1212 checking incoming mail. If aliasing generates multiple addresses, you
1213 probably don't want to do this. Exim therefore treats the generation of
1214 just a single new address as a special case, and continues on to verify the
1215 generated address. */
1217 if (!full_info && /* Stop if short info wanted AND */
1218 (addr_new == NULL || /* No new address OR */
1219 addr_new->next != NULL || /* More than one new address OR */
1220 testflag(addr_new, af_pfr))) /* New address is pfr */
1222 if (f != NULL) fprintf(f, "%s %s\n", address,
1223 address_test_mode? "is deliverable" : "verified");
1225 /* If we have carried on to verify a child address, we want the value
1226 of $address_data to be that of the child */
1228 vaddr->p.address_data = addr->p.address_data;
1232 } /* Loop for generated addresses */
1234 /* Display the full results of the successful routing, including any generated
1235 addresses. Control gets here only when full_info is set, which requires f not
1236 to be NULL, and this occurs only when a top-level verify is called with the
1237 debugging switch on.
1239 If there are no local and no remote addresses, and there were no pipes, files,
1240 or autoreplies, and there were no errors or deferments, the message is to be
1241 discarded, usually because of the use of :blackhole: in an alias file. */
1243 if (allok && addr_local == NULL && addr_remote == NULL)
1244 fprintf(f, "mail to %s is discarded\n", address);
1246 else for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++)
1248 while (addr_list != NULL)
1250 address_item *addr = addr_list;
1251 address_item *p = addr->parent;
1252 addr_list = addr->next;
1254 fprintf(f, "%s", CS addr->address);
1255 #ifdef EXPERIMENTAL_SRS
1256 if(addr->p.srs_sender)
1257 fprintf(f, " [srs = %s]", addr->p.srs_sender);
1261 fprintf(f, "\n <-- %s", p->address);
1266 /* Show router, and transport */
1268 fprintf(f, "router = %s, ", addr->router->name);
1269 fprintf(f, "transport = %s\n", (addr->transport == NULL)? US"unset" :
1270 addr->transport->name);
1272 /* Show any hosts that are set up by a router unless the transport
1273 is going to override them; fiddle a bit to get a nice format. */
1275 if (addr->host_list != NULL && addr->transport != NULL &&
1276 !addr->transport->overrides_hosts)
1281 for (h = addr->host_list; h != NULL; h = h->next)
1283 int len = Ustrlen(h->name);
1284 if (len > maxlen) maxlen = len;
1285 len = (h->address != NULL)? Ustrlen(h->address) : 7;
1286 if (len > maxaddlen) maxaddlen = len;
1288 for (h = addr->host_list; h != NULL; h = h->next)
1290 int len = Ustrlen(h->name);
1291 fprintf(f, " host %s ", h->name);
1292 while (len++ < maxlen) fprintf(f, " ");
1293 if (h->address != NULL)
1295 fprintf(f, "[%s] ", h->address);
1296 len = Ustrlen(h->address);
1298 else if (!addr->transport->info->local) /* Omit [unknown] for local */
1300 fprintf(f, "[unknown] ");
1304 while (len++ < maxaddlen) fprintf(f," ");
1305 if (h->mx >= 0) fprintf(f, "MX=%d", h->mx);
1306 if (h->port != PORT_NONE) fprintf(f, " port=%d", h->port);
1307 if (h->status == hstatus_unusable) fprintf(f, " ** unusable **");
1314 /* Will be DEFER or FAIL if any one address has, only for full_info (which is
1315 the -bv or -bt case). */
1323 /*************************************************
1324 * Check headers for syntax errors *
1325 *************************************************/
1327 /* This function checks those header lines that contain addresses, and verifies
1328 that all the addresses therein are syntactially correct.
1331 msgptr where to put an error message
1338 verify_check_headers(uschar **msgptr)
1343 for (h = header_list; h != NULL; h = h->next)
1345 if (h->type != htype_from &&
1346 h->type != htype_reply_to &&
1347 h->type != htype_sender &&
1348 h->type != htype_to &&
1349 h->type != htype_cc &&
1350 h->type != htype_bcc)
1353 colon = Ustrchr(h->text, ':');
1355 while (isspace(*s)) s++;
1357 parse_allow_group = TRUE; /* Allow group syntax */
1359 /* Loop for multiple addresses in the header */
1363 uschar *ss = parse_find_address_end(s, FALSE);
1364 uschar *recipient, *errmess;
1365 int terminator = *ss;
1366 int start, end, domain;
1368 /* Temporarily terminate the string at this point, and extract the
1369 operative address within. */
1372 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
1375 /* Permit an unqualified address only if the message is local, or if the
1376 sending host is configured to be permitted to send them. */
1378 if (recipient != NULL && domain == 0)
1380 if (h->type == htype_from || h->type == htype_sender)
1382 if (!allow_unqualified_sender) recipient = NULL;
1386 if (!allow_unqualified_recipient) recipient = NULL;
1388 if (recipient == NULL) errmess = US"unqualified address not permitted";
1391 /* It's an error if no address could be extracted, except for the special
1392 case of an empty address. */
1394 if (recipient == NULL && Ustrcmp(errmess, "empty address") != 0)
1396 uschar *verb = US"is";
1400 /* Arrange not to include any white space at the end in the
1403 while (t > s && isspace(t[-1])) t--;
1405 /* Add the address which failed to the error message, since in a
1406 header with very many addresses it is sometimes hard to spot
1407 which one is at fault. However, limit the amount of address to
1408 quote - cases have been seen where, for example, a missing double
1409 quote in a humungous To: header creates an "address" that is longer
1410 than string_sprintf can handle. */
1419 *msgptr = string_printing(
1420 string_sprintf("%s: failing address in \"%.*s\" header %s: %.*s",
1421 errmess, colon - h->text, h->text, verb, len, s));
1426 /* Advance to the next address */
1428 s = ss + (terminator? 1:0);
1429 while (isspace(*s)) s++;
1430 } /* Next address */
1439 /*************************************************
1440 * Find if verified sender *
1441 *************************************************/
1443 /* Usually, just a single address is verified as the sender of the message.
1444 However, Exim can be made to verify other addresses as well (often related in
1445 some way), and this is useful in some environments. There may therefore be a
1446 chain of such addresses that have previously been tested. This function finds
1447 whether a given address is on the chain.
1449 Arguments: the address to be verified
1450 Returns: pointer to an address item, or NULL
1454 verify_checked_sender(uschar *sender)
1457 for (addr = sender_verified_list; addr != NULL; addr = addr->next)
1458 if (Ustrcmp(sender, addr->address) == 0) break;
1466 /*************************************************
1467 * Get valid header address *
1468 *************************************************/
1470 /* Scan the originator headers of the message, looking for an address that
1471 verifies successfully. RFC 822 says:
1473 o The "Sender" field mailbox should be sent notices of
1474 any problems in transport or delivery of the original
1475 messages. If there is no "Sender" field, then the
1476 "From" field mailbox should be used.
1478 o If the "Reply-To" field exists, then the reply should
1479 go to the addresses indicated in that field and not to
1480 the address(es) indicated in the "From" field.
1482 So we check a Sender field if there is one, else a Reply_to field, else a From
1483 field. As some strange messages may have more than one of these fields,
1484 especially if they are resent- fields, check all of them if there is more than
1488 user_msgptr points to where to put a user error message
1489 log_msgptr points to where to put a log error message
1490 callout timeout for callout check (passed to verify_address())
1491 callout_overall overall callout timeout (ditto)
1492 callout_connect connect callout timeout (ditto)
1493 se_mailfrom mailfrom for verify; NULL => ""
1494 pm_mailfrom sender for pm callout check (passed to verify_address())
1495 options callout options (passed to verify_address())
1496 verrno where to put the address basic_errno
1498 If log_msgptr is set to something without setting user_msgptr, the caller
1499 normally uses log_msgptr for both things.
1501 Returns: result of the verification attempt: OK, FAIL, or DEFER;
1502 FAIL is given if no appropriate headers are found
1506 verify_check_header_address(uschar **user_msgptr, uschar **log_msgptr,
1507 int callout, int callout_overall, int callout_connect, uschar *se_mailfrom,
1508 uschar *pm_mailfrom, int options, int *verrno)
1510 static int header_types[] = { htype_sender, htype_reply_to, htype_from };
1514 for (i = 0; i < 3; i++)
1517 for (h = header_list; h != NULL; h = h->next)
1519 int terminator, new_ok;
1520 uschar *s, *ss, *endname;
1522 if (h->type != header_types[i]) continue;
1523 s = endname = Ustrchr(h->text, ':') + 1;
1527 address_item *vaddr;
1529 while (isspace(*s) || *s == ',') s++;
1530 if (*s == 0) break; /* End of header */
1532 ss = parse_find_address_end(s, FALSE);
1534 /* The terminator is a comma or end of header, but there may be white
1535 space preceding it (including newline for the last address). Move back
1536 past any white space so we can check against any cached envelope sender
1537 address verifications. */
1539 while (isspace(ss[-1])) ss--;
1543 HDEBUG(D_verify) debug_printf("verifying %.*s header address %s\n",
1544 (int)(endname - h->text), h->text, s);
1546 /* See if we have already verified this address as an envelope sender,
1547 and if so, use the previous answer. */
1549 vaddr = verify_checked_sender(s);
1551 if (vaddr != NULL && /* Previously checked */
1552 (callout <= 0 || /* No callout needed; OR */
1553 vaddr->special_action > 256)) /* Callout was done */
1555 new_ok = vaddr->special_action & 255;
1556 HDEBUG(D_verify) debug_printf("previously checked as envelope sender\n");
1557 *ss = terminator; /* Restore shortened string */
1560 /* Otherwise we run the verification now. We must restore the shortened
1561 string before running the verification, so the headers are correct, in
1562 case there is any rewriting. */
1566 int start, end, domain;
1567 uschar *address = parse_extract_address(s, log_msgptr, &start,
1568 &end, &domain, FALSE);
1572 /* If verification failed because of a syntax error, fail this
1573 function, and ensure that the failing address gets added to the error
1576 if (address == NULL)
1579 if (*log_msgptr != NULL)
1581 while (ss > s && isspace(ss[-1])) ss--;
1582 *log_msgptr = string_sprintf("syntax error in '%.*s' header when "
1583 "scanning for sender: %s in \"%.*s\"",
1584 endname - h->text, h->text, *log_msgptr, ss - s, s);
1589 /* Else go ahead with the sender verification. But it isn't *the*
1590 sender of the message, so set vopt_fake_sender to stop sender_address
1591 being replaced after rewriting or qualification. */
1595 vaddr = deliver_make_addr(address, FALSE);
1596 new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender,
1597 callout, callout_overall, callout_connect, se_mailfrom,
1602 /* We now have the result, either newly found, or cached. If we are
1603 giving out error details, set a specific user error. This means that the
1604 last of these will be returned to the user if all three fail. We do not
1605 set a log message - the generic one below will be used. */
1609 *verrno = vaddr->basic_errno;
1610 if (smtp_return_error_details)
1612 *user_msgptr = string_sprintf("Rejected after DATA: "
1613 "could not verify \"%.*s\" header address\n%s: %s",
1614 endname - h->text, h->text, vaddr->address, vaddr->message);
1618 /* Success or defer */
1620 if (new_ok == OK) return OK;
1621 if (new_ok == DEFER) yield = DEFER;
1623 /* Move on to any more addresses in the header */
1630 if (yield == FAIL && *log_msgptr == NULL)
1631 *log_msgptr = US"there is no valid sender in any header line";
1633 if (yield == DEFER && *log_msgptr == NULL)
1634 *log_msgptr = US"all attempts to verify a sender in a header line deferred";
1642 /*************************************************
1643 * Get RFC 1413 identification *
1644 *************************************************/
1646 /* Attempt to get an id from the sending machine via the RFC 1413 protocol. If
1647 the timeout is set to zero, then the query is not done. There may also be lists
1648 of hosts and nets which are exempt. To guard against malefactors sending
1649 non-printing characters which could, for example, disrupt a message's headers,
1650 make sure the string consists of printing characters only.
1653 port the port to connect to; usually this is IDENT_PORT (113), but when
1654 running in the test harness with -bh a different value is used.
1658 Side effect: any received ident value is put in sender_ident (NULL otherwise)
1662 verify_get_ident(int port)
1664 int sock, host_af, qlen;
1665 int received_sender_port, received_interface_port, n;
1667 uschar buffer[2048];
1669 /* Default is no ident. Check whether we want to do an ident check for this
1672 sender_ident = NULL;
1673 if (rfc1413_query_timeout <= 0 || verify_check_host(&rfc1413_hosts) != OK)
1676 DEBUG(D_ident) debug_printf("doing ident callback\n");
1678 /* Set up a connection to the ident port of the remote host. Bind the local end
1679 to the incoming interface address. If the sender host address is an IPv6
1680 address, the incoming interface address will also be IPv6. */
1682 host_af = (Ustrchr(sender_host_address, ':') == NULL)? AF_INET : AF_INET6;
1683 sock = ip_socket(SOCK_STREAM, host_af);
1684 if (sock < 0) return;
1686 if (ip_bind(sock, host_af, interface_address, 0) < 0)
1688 DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n",
1693 if (ip_connect(sock, host_af, sender_host_address, port, rfc1413_query_timeout)
1696 if (errno == ETIMEDOUT && (log_extra_selector & LX_ident_timeout) != 0)
1698 log_write(0, LOG_MAIN, "ident connection to %s timed out",
1699 sender_host_address);
1703 DEBUG(D_ident) debug_printf("ident connection to %s failed: %s\n",
1704 sender_host_address, strerror(errno));
1709 /* Construct and send the query. */
1711 sprintf(CS buffer, "%d , %d\r\n", sender_host_port, interface_port);
1712 qlen = Ustrlen(buffer);
1713 if (send(sock, buffer, qlen, 0) < 0)
1715 DEBUG(D_ident) debug_printf("ident send failed: %s\n", strerror(errno));
1719 /* Read a response line. We put it into the rest of the buffer, using several
1720 recv() calls if necessary. */
1728 int size = sizeof(buffer) - (p - buffer);
1730 if (size <= 0) goto END_OFF; /* Buffer filled without seeing \n. */
1731 count = ip_recv(sock, p, size, rfc1413_query_timeout);
1732 if (count <= 0) goto END_OFF; /* Read error or EOF */
1734 /* Scan what we just read, to see if we have reached the terminating \r\n. Be
1735 generous, and accept a plain \n terminator as well. The only illegal
1738 for (pp = p; pp < p + count; pp++)
1740 if (*pp == 0) goto END_OFF; /* Zero octet not allowed */
1743 if (pp[-1] == '\r') pp--;
1745 goto GOT_DATA; /* Break out of both loops */
1749 /* Reached the end of the data without finding \n. Let the loop continue to
1750 read some more, if there is room. */
1757 /* We have received a line of data. Check it carefully. It must start with the
1758 same two port numbers that we sent, followed by data as defined by the RFC. For
1761 12345 , 25 : USERID : UNIX :root
1763 However, the amount of white space may be different to what we sent. In the
1764 "osname" field there may be several sub-fields, comma separated. The data we
1765 actually want to save follows the third colon. Some systems put leading spaces
1766 in it - we discard those. */
1768 if (sscanf(CS buffer + qlen, "%d , %d%n", &received_sender_port,
1769 &received_interface_port, &n) != 2 ||
1770 received_sender_port != sender_host_port ||
1771 received_interface_port != interface_port)
1774 p = buffer + qlen + n;
1775 while(isspace(*p)) p++;
1776 if (*p++ != ':') goto END_OFF;
1777 while(isspace(*p)) p++;
1778 if (Ustrncmp(p, "USERID", 6) != 0) goto END_OFF;
1780 while(isspace(*p)) p++;
1781 if (*p++ != ':') goto END_OFF;
1782 while (*p != 0 && *p != ':') p++;
1783 if (*p++ == 0) goto END_OFF;
1784 while(isspace(*p)) p++;
1785 if (*p == 0) goto END_OFF;
1787 /* The rest of the line is the data we want. We turn it into printing
1788 characters when we save it, so that it cannot mess up the format of any logging
1789 or Received: lines into which it gets inserted. We keep a maximum of 127
1792 sender_ident = string_printing(string_copyn(p, 127));
1793 DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident);
1803 /*************************************************
1804 * Match host to a single host-list item *
1805 *************************************************/
1807 /* This function compares a host (name or address) against a single item
1808 from a host list. The host name gets looked up if it is needed and is not
1809 already known. The function is called from verify_check_this_host() via
1810 match_check_list(), which is why most of its arguments are in a single block.
1813 arg the argument block (see below)
1814 ss the host-list item
1815 valueptr where to pass back looked up data, or NULL
1816 error for error message when returning ERROR
1819 host_name the host name or NULL, implying use sender_host_name and
1820 sender_host_aliases, looking them up if required
1821 host_address the host address
1822 host_ipv4 the IPv4 address taken from an IPv6 one
1826 DEFER lookup deferred
1827 ERROR failed to find the host name or IP address
1828 unknown lookup type specified
1832 check_host(void *arg, uschar *ss, uschar **valueptr, uschar **error)
1834 check_host_block *cb = (check_host_block *)arg;
1836 BOOL isquery = FALSE;
1837 uschar *semicolon, *t;
1840 /* Optimize for the special case when the pattern is "*". */
1842 if (*ss == '*' && ss[1] == 0) return OK;
1844 /* If the pattern is empty, it matches only in the case when there is no host -
1845 this can occur in ACL checking for SMTP input using the -bs option. In this
1846 situation, the host address is the empty string. */
1848 if (cb->host_address[0] == 0) return (*ss == 0)? OK : FAIL;
1849 if (*ss == 0) return FAIL;
1851 /* If the pattern is precisely "@" then match against the primary host name;
1852 if it's "@[]" match against the local host's IP addresses. */
1856 if (ss[1] == 0) ss = primary_hostname;
1857 else if (Ustrcmp(ss, "@[]") == 0)
1859 ip_address_item *ip;
1860 for (ip = host_find_interfaces(); ip != NULL; ip = ip->next)
1861 if (Ustrcmp(ip->address, cb->host_address) == 0) return OK;
1866 /* If the pattern is an IP address, optionally followed by a bitmask count, do
1867 a (possibly masked) comparision with the current IP address. */
1869 if (string_is_ip_address(ss, &maskoffset) > 0)
1870 return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL);
1872 /* If the item is of the form net[n]-lookup;<file|query> then it is a lookup on
1873 a masked IP network, in textual form. The net- stuff really only applies to
1874 single-key lookups where the key is implicit. For query-style lookups the key
1875 is specified in the query. From release 4.30, the use of net- for query style
1876 is no longer needed, but we retain it for backward compatibility. */
1878 if (Ustrncmp(ss, "net", 3) == 0 && (semicolon = Ustrchr(ss, ';')) != NULL)
1881 for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0';
1888 uschar *filename, *key, *result;
1891 /* If no mask was supplied, set a negative value */
1893 if (mlen == 0 && t == ss+4) mlen = -1;
1895 /* Find the search type */
1897 search_type = search_findtype(t, semicolon - t);
1899 if (search_type < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
1900 search_error_message);
1902 /* Adjust parameters for the type of lookup. For a query-style
1903 lookup, there is no file name, and the "key" is just the query. For
1904 a single-key lookup, the key is the current IP address, masked
1905 appropriately, and reconverted to text form, with the mask appended.
1906 For IPv6 addresses, specify dot separators instead of colons. */
1908 if (mac_islookup(search_type, lookup_querystyle))
1911 key = semicolon + 1;
1915 insize = host_aton(cb->host_address, incoming);
1916 host_mask(insize, incoming, mlen);
1917 (void)host_nmtoa(insize, incoming, mlen, buffer, '.');
1919 filename = semicolon + 1;
1922 /* Now do the actual lookup; note that there is no search_close() because
1923 of the caching arrangements. */
1925 handle = search_open(filename, search_type, 0, NULL, NULL);
1926 if (handle == NULL) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
1927 search_error_message);
1928 result = search_find(handle, filename, key, -1, NULL, 0, 0, NULL);
1929 if (valueptr != NULL) *valueptr = result;
1930 return (result != NULL)? OK : search_find_defer? DEFER: FAIL;
1934 /* The pattern is not an IP address or network reference of any kind. That is,
1935 it is a host name pattern. Check the characters of the pattern to see if they
1936 comprise only letters, digits, full stops, and hyphens (the constituents of
1937 domain names). Allow underscores, as they are all too commonly found. Sigh.
1938 Also, if allow_utf8_domains is set, allow top-bit characters. */
1940 for (t = ss; *t != 0; t++)
1941 if (!isalnum(*t) && *t != '.' && *t != '-' && *t != '_' &&
1942 (!allow_utf8_domains || *t < 128)) break;
1944 /* If the pattern is a complete domain name, with no fancy characters, look up
1945 its IP address and match against that. Note that a multi-homed host will add
1946 items to the chain. */
1956 rc = host_find_byname(&h, NULL, NULL, FALSE);
1957 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
1960 for (hh = &h; hh != NULL; hh = hh->next)
1962 if (Ustrcmp(hh->address, (Ustrchr(hh->address, ':') == NULL)?
1963 cb->host_ipv4 : cb->host_address) == 0)
1968 if (rc == HOST_FIND_AGAIN) return DEFER;
1969 *error = string_sprintf("failed to find IP address for %s", ss);
1973 /* Almost all subsequent comparisons require the host name, and can be done
1974 using the general string matching function. When this function is called for
1975 outgoing hosts, the name is always given explicitly. If it is NULL, it means we
1976 must use sender_host_name and its aliases, looking them up if necessary. */
1978 if (cb->host_name != NULL) /* Explicit host name given */
1979 return match_check_string(cb->host_name, ss, -1, TRUE, TRUE, TRUE,
1982 /* Host name not given; in principle we need the sender host name and its
1983 aliases. However, for query-style lookups, we do not need the name if the
1984 query does not contain $sender_host_name. From release 4.23, a reference to
1985 $sender_host_name causes it to be looked up, so we don't need to do the lookup
1988 if ((semicolon = Ustrchr(ss, ';')) != NULL)
1991 int partial, affixlen, starflags, id;
1994 id = search_findtype_partial(ss, &partial, &affix, &affixlen, &starflags);
1997 if (id < 0) /* Unknown lookup type */
1999 log_write(0, LOG_MAIN|LOG_PANIC, "%s in host list item \"%s\"",
2000 search_error_message, ss);
2003 isquery = mac_islookup(id, lookup_querystyle);
2008 switch(match_check_string(US"", ss, -1, TRUE, TRUE, TRUE, valueptr))
2011 case DEFER: return DEFER;
2012 default: return FAIL;
2016 /* Not a query-style lookup; must ensure the host name is present, and then we
2017 do a check on the name and all its aliases. */
2019 if (sender_host_name == NULL)
2021 HDEBUG(D_host_lookup)
2022 debug_printf("sender host name required, to match against %s\n", ss);
2023 if (host_lookup_failed || host_name_lookup() != OK)
2025 *error = string_sprintf("failed to find host name for %s",
2026 sender_host_address);;
2029 host_build_sender_fullhost();
2032 /* Match on the sender host name, using the general matching function */
2034 switch(match_check_string(sender_host_name, ss, -1, TRUE, TRUE, TRUE,
2038 case DEFER: return DEFER;
2041 /* If there are aliases, try matching on them. */
2043 aliases = sender_host_aliases;
2044 while (*aliases != NULL)
2046 switch(match_check_string(*aliases++, ss, -1, TRUE, TRUE, TRUE, valueptr))
2049 case DEFER: return DEFER;
2058 /*************************************************
2059 * Check a specific host matches a host list *
2060 *************************************************/
2062 /* This function is passed a host list containing items in a number of
2063 different formats and the identity of a host. Its job is to determine whether
2064 the given host is in the set of hosts defined by the list. The host name is
2065 passed as a pointer so that it can be looked up if needed and not already
2066 known. This is commonly the case when called from verify_check_host() to check
2067 an incoming connection. When called from elsewhere the host name should usually
2070 This function is now just a front end to match_check_list(), which runs common
2071 code for scanning a list. We pass it the check_host() function to perform a
2075 listptr pointer to the host list
2076 cache_bits pointer to cache for named lists, or NULL
2077 host_name the host name or NULL, implying use sender_host_name and
2078 sender_host_aliases, looking them up if required
2079 host_address the IP address
2080 valueptr if not NULL, data from a lookup is passed back here
2082 Returns: OK if the host is in the defined set
2083 FAIL if the host is not in the defined set,
2084 DEFER if a data lookup deferred (not a host lookup)
2086 If the host name was needed in order to make a comparison, and could not be
2087 determined from the IP address, the result is FAIL unless the item
2088 "+allow_unknown" was met earlier in the list, in which case OK is returned. */
2091 verify_check_this_host(uschar **listptr, unsigned int *cache_bits,
2092 uschar *host_name, uschar *host_address, uschar **valueptr)
2095 unsigned int *local_cache_bits = cache_bits;
2096 uschar *save_host_address = deliver_host_address;
2097 check_host_block cb;
2098 cb.host_name = host_name;
2099 cb.host_address = host_address;
2101 if (valueptr != NULL) *valueptr = NULL;
2103 /* If the host address starts off ::ffff: it is an IPv6 address in
2104 IPv4-compatible mode. Find the IPv4 part for checking against IPv4
2107 cb.host_ipv4 = (Ustrncmp(host_address, "::ffff:", 7) == 0)?
2108 host_address + 7 : host_address;
2110 /* During the running of the check, put the IP address into $host_address. In
2111 the case of calls from the smtp transport, it will already be there. However,
2112 in other calls (e.g. when testing ignore_target_hosts), it won't. Just to be on
2113 the safe side, any existing setting is preserved, though as I write this
2114 (November 2004) I can't see any cases where it is actually needed. */
2116 deliver_host_address = host_address;
2117 rc = match_check_list(
2118 listptr, /* the list */
2119 0, /* separator character */
2120 &hostlist_anchor, /* anchor pointer */
2121 &local_cache_bits, /* cache pointer */
2122 check_host, /* function for testing */
2123 &cb, /* argument for function */
2124 MCL_HOST, /* type of check */
2125 (host_address == sender_host_address)?
2126 US"host" : host_address, /* text for debugging */
2127 valueptr); /* where to pass back data */
2128 deliver_host_address = save_host_address;
2135 /*************************************************
2136 * Check the remote host matches a list *
2137 *************************************************/
2139 /* This is a front end to verify_check_this_host(), created because checking
2140 the remote host is a common occurrence. With luck, a good compiler will spot
2141 the tail recursion and optimize it. If there's no host address, this is
2142 command-line SMTP input - check against an empty string for the address.
2145 listptr pointer to the host list
2147 Returns: the yield of verify_check_this_host(),
2148 i.e. OK, FAIL, or DEFER
2152 verify_check_host(uschar **listptr)
2154 return verify_check_this_host(listptr, sender_host_cache, NULL,
2155 (sender_host_address == NULL)? US"" : sender_host_address, NULL);
2162 /*************************************************
2163 * Invert an IP address for a DNS black list *
2164 *************************************************/
2168 buffer where to put the answer
2169 address the address to invert
2173 invert_address(uschar *buffer, uschar *address)
2176 uschar *bptr = buffer;
2178 /* If this is an IPv4 address mapped into IPv6 format, adjust the pointer
2179 to the IPv4 part only. */
2181 if (Ustrncmp(address, "::ffff:", 7) == 0) address += 7;
2183 /* Handle IPv4 address: when HAVE_IPV6 is false, the result of host_aton() is
2186 if (host_aton(address, bin) == 1)
2190 for (i = 0; i < 4; i++)
2192 sprintf(CS bptr, "%d.", x & 255);
2193 while (*bptr) bptr++;
2198 /* Handle IPv6 address. Actually, as far as I know, there are no IPv6 addresses
2199 in any DNS black lists, and the format in which they will be looked up is
2200 unknown. This is just a guess. */
2206 for (j = 3; j >= 0; j--)
2209 for (i = 0; i < 8; i++)
2211 sprintf(CS bptr, "%x.", x & 15);
2212 while (*bptr) bptr++;
2222 /*************************************************
2223 * Perform a single dnsbl lookup *
2224 *************************************************/
2226 /* This function is called from verify_check_dnsbl() below.
2229 domain the outer dnsbl domain (for debug message)
2230 keydomain the current keydomain (for debug message)
2231 query the domain to be looked up
2232 iplist the list of matching IP addresses
2233 bitmask true if bitmask matching is wanted
2234 invert_result true if result to be inverted
2235 defer_return what to return for a defer
2237 Returns: OK if lookup succeeded
2242 one_check_dnsbl(uschar *domain, uschar *keydomain, uschar *query,
2243 uschar *iplist, BOOL bitmask, BOOL invert_result, int defer_return)
2248 dnsbl_cache_block *cb;
2249 int old_pool = store_pool;
2251 /* Look for this query in the cache. */
2253 t = tree_search(dnsbl_cache, query);
2255 /* If not cached from a previous lookup, we must do a DNS lookup, and
2256 cache the result in permanent memory. */
2260 store_pool = POOL_PERM;
2262 /* Set up a tree entry to cache the lookup */
2264 t = store_get(sizeof(tree_node) + Ustrlen(query));
2265 Ustrcpy(t->name, query);
2266 t->data.ptr = cb = store_get(sizeof(dnsbl_cache_block));
2267 (void)tree_insertnode(&dnsbl_cache, t);
2269 /* Do the DNS loopup . */
2271 HDEBUG(D_dnsbl) debug_printf("new DNS lookup for %s\n", query);
2272 cb->rc = dns_basic_lookup(&dnsa, query, T_A);
2273 cb->text_set = FALSE;
2277 /* If the lookup succeeded, cache the RHS address. The code allows for
2278 more than one address - this was for complete generality and the possible
2279 use of A6 records. However, A6 records have been reduced to experimental
2280 status (August 2001) and may die out. So they may never get used at all,
2281 let alone in dnsbl records. However, leave the code here, just in case.
2283 Quite apart from one A6 RR generating multiple addresses, there are DNS
2284 lists that return more than one A record, so we must handle multiple
2285 addresses generated in that way as well. */
2287 if (cb->rc == DNS_SUCCEED)
2290 dns_address **addrp = &(cb->rhs);
2291 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2293 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
2295 if (rr->type == T_A)
2297 dns_address *da = dns_address_from_rr(&dnsa, rr);
2301 while (da->next != NULL) da = da->next;
2302 addrp = &(da->next);
2307 /* If we didn't find any A records, change the return code. This can
2308 happen when there is a CNAME record but there are no A records for what
2311 if (cb->rhs == NULL) cb->rc = DNS_NODATA;
2314 store_pool = old_pool;
2317 /* Previous lookup was cached */
2321 HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
2325 /* We now have the result of the DNS lookup, either newly done, or cached
2326 from a previous call. If the lookup succeeded, check against the address
2327 list if there is one. This may be a positive equality list (introduced by
2328 "="), a negative equality list (introduced by "!="), a positive bitmask
2329 list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/
2331 if (cb->rc == DNS_SUCCEED)
2333 dns_address *da = NULL;
2334 uschar *addlist = cb->rhs->address;
2336 /* For A and AAAA records, there may be multiple addresses from multiple
2337 records. For A6 records (currently not expected to be used) there may be
2338 multiple addresses from a single record. */
2340 for (da = cb->rhs->next; da != NULL; da = da->next)
2341 addlist = string_sprintf("%s, %s", addlist, da->address);
2343 HDEBUG(D_dnsbl) debug_printf("DNS lookup for %s succeeded (yielding %s)\n",
2346 /* Address list check; this can be either for equality, or via a bitmask.
2347 In the latter case, all the bits must match. */
2353 uschar *ptr = iplist;
2355 while (string_nextinlist(&ptr, &ipsep, ip, sizeof(ip)) != NULL)
2357 /* Handle exact matching */
2360 for (da = cb->rhs; da != NULL; da = da->next)
2362 if (Ustrcmp(CS da->address, ip) == 0) break;
2365 /* Handle bitmask matching */
2371 /* At present, all known DNS blocking lists use A records, with
2372 IPv4 addresses on the RHS encoding the information they return. I
2373 wonder if this will linger on as the last vestige of IPv4 when IPv6
2374 is ubiquitous? Anyway, for now we use paranoia code to completely
2375 ignore IPv6 addresses. The default mask is 0, which always matches.
2376 We change this only for IPv4 addresses in the list. */
2378 if (host_aton(ip, address) == 1) mask = address[0];
2380 /* Scan the returned addresses, skipping any that are IPv6 */
2382 for (da = cb->rhs; da != NULL; da = da->next)
2384 if (host_aton(da->address, address) != 1) continue;
2385 if ((address[0] & mask) == mask) break;
2389 /* Break out if a match has been found */
2391 if (da != NULL) break;
2396 (a) No IP address in a positive list matched, or
2397 (b) An IP address in a negative list did match
2399 then behave as if the DNSBL lookup had not succeeded, i.e. the host is
2402 if (invert_result != (da == NULL))
2406 debug_printf("=> but we are not accepting this block class because\n");
2407 debug_printf("=> there was %s match for %c%s\n",
2408 invert_result? "an exclude":"no", bitmask? '&' : '=', iplist);
2414 /* Either there was no IP list, or the record matched. Look up a TXT record
2415 if it hasn't previously been done. */
2419 cb->text_set = TRUE;
2420 if (dns_basic_lookup(&dnsa, query, T_TXT) == DNS_SUCCEED)
2423 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2425 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
2426 if (rr->type == T_TXT) break;
2429 int len = (rr->data)[0];
2430 if (len > 511) len = 127;
2431 store_pool = POOL_PERM;
2432 cb->text = string_sprintf("%.*s", len, (const uschar *)(rr->data+1));
2433 store_pool = old_pool;
2438 dnslist_value = addlist;
2439 dnslist_text = cb->text;
2443 /* There was a problem with the DNS lookup */
2445 if (cb->rc != DNS_NOMATCH && cb->rc != DNS_NODATA)
2447 log_write(L_dnslist_defer, LOG_MAIN,
2448 "DNS list lookup defer (probably timeout) for %s: %s", query,
2449 (defer_return == OK)? US"assumed in list" :
2450 (defer_return == FAIL)? US"assumed not in list" :
2451 US"returned DEFER");
2452 return defer_return;
2455 /* No entry was found in the DNS; continue for next domain */
2459 debug_printf("DNS lookup for %s failed\n", query);
2460 debug_printf("=> that means %s is not listed at %s\n",
2470 /*************************************************
2471 * Check host against DNS black lists *
2472 *************************************************/
2474 /* This function runs checks against a list of DNS black lists, until one
2475 matches. Each item on the list can be of the form
2477 domain=ip-address/key
2479 The domain is the right-most domain that is used for the query, for example,
2480 blackholes.mail-abuse.org. If the IP address is present, there is a match only
2481 if the DNS lookup returns a matching IP address. Several addresses may be
2482 given, comma-separated, for example: x.y.z=127.0.0.1,127.0.0.2.
2484 If no key is given, what is looked up in the domain is the inverted IP address
2485 of the current client host. If a key is given, it is used to construct the
2486 domain for the lookup. For example,
2488 dsn.rfc-ignorant.org/$sender_address_domain
2490 After finding a match in the DNS, the domain is placed in $dnslist_domain, and
2491 then we check for a TXT record for an error message, and if found, save its
2492 value in $dnslist_text. We also cache everything in a tree, to optimize
2495 Note: an address for testing RBL is 192.203.178.39
2496 Note: an address for testing DUL is 192.203.178.4
2497 Note: a domain for testing RFCI is example.tld.dsn.rfc-ignorant.org
2500 listptr the domain/address/data list
2502 Returns: OK successful lookup (i.e. the address is on the list), or
2503 lookup deferred after +include_unknown
2504 FAIL name not found, or no data found for the given type, or
2505 lookup deferred after +exclude_unknown (default)
2506 DEFER lookup failure, if +defer_unknown was set
2510 verify_check_dnsbl(uschar **listptr)
2513 int defer_return = FAIL;
2514 BOOL invert_result = FALSE;
2515 uschar *list = *listptr;
2518 uschar buffer[1024];
2519 uschar query[256]; /* DNS domain max length */
2520 uschar revadd[128]; /* Long enough for IPv6 address */
2522 /* Indicate that the inverted IP address is not yet set up */
2526 /* In case this is the first time the DNS resolver is being used. */
2528 dns_init(FALSE, FALSE);
2530 /* Loop through all the domains supplied, until something matches */
2532 while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
2536 BOOL bitmask = FALSE;
2540 HDEBUG(D_dnsbl) debug_printf("DNS list check: %s\n", domain);
2542 /* Deal with special values that change the behaviour on defer */
2544 if (domain[0] == '+')
2546 if (strcmpic(domain, US"+include_unknown") == 0) defer_return = OK;
2547 else if (strcmpic(domain, US"+exclude_unknown") == 0) defer_return = FAIL;
2548 else if (strcmpic(domain, US"+defer_unknown") == 0) defer_return = DEFER;
2550 log_write(0, LOG_MAIN|LOG_PANIC, "unknown item in dnslist (ignored): %s",
2555 /* See if there's explicit data to be looked up */
2557 key = Ustrchr(domain, '/');
2558 if (key != NULL) *key++ = 0;
2560 /* See if there's a list of addresses supplied after the domain name. This is
2561 introduced by an = or a & character; if preceded by ! we invert the result.
2564 iplist = Ustrchr(domain, '=');
2568 iplist = Ustrchr(domain, '&');
2573 if (iplist > domain && iplist[-1] == '!')
2575 invert_result = TRUE;
2581 /* Check that what we have left is a sensible domain name. There is no reason
2582 why these domains should in fact use the same syntax as hosts and email
2583 domains, but in practice they seem to. However, there is little point in
2584 actually causing an error here, because that would no doubt hold up incoming
2585 mail. Instead, I'll just log it. */
2587 for (s = domain; *s != 0; s++)
2589 if (!isalnum(*s) && *s != '-' && *s != '.')
2591 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
2592 "strange characters - is this right?", domain);
2597 /* If there is no key string, construct the query by adding the domain name
2598 onto the inverted host address, and perform a single DNS lookup. */
2602 if (sender_host_address == NULL) return FAIL; /* can never match */
2603 if (revadd[0] == 0) invert_address(revadd, sender_host_address);
2604 frc = string_format(query, sizeof(query), "%s%s", revadd, domain);
2608 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
2609 "(ignored): %s...", query);
2613 rc = one_check_dnsbl(domain, sender_host_address, query, iplist, bitmask,
2614 invert_result, defer_return);
2618 dnslist_domain = string_copy(domain);
2619 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
2620 sender_host_address, domain);
2623 if (rc != FAIL) return rc; /* OK or DEFER */
2626 /* If there is a key string, it can be a list of domains or IP addresses to
2627 be concatenated with the main domain. */
2634 uschar keybuffer[256];
2636 while ((keydomain = string_nextinlist(&key, &keysep, keybuffer,
2637 sizeof(keybuffer))) != NULL)
2639 if (string_is_ip_address(keydomain, NULL) > 0)
2641 uschar keyrevadd[128];
2642 invert_address(keyrevadd, keydomain);
2643 frc = string_format(query, sizeof(query), "%s%s", keyrevadd, domain);
2647 frc = string_format(query, sizeof(query), "%s.%s", keydomain, domain);
2652 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
2653 "(ignored): %s...", query);
2657 rc = one_check_dnsbl(domain, keydomain, query, iplist, bitmask,
2658 invert_result, defer_return);
2662 dnslist_domain = string_copy(domain);
2663 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
2668 /* If the lookup deferred, remember this fact. We keep trying the rest
2669 of the list to see if we get a useful result, and if we don't, we return
2670 DEFER at the end. */
2672 if (rc == DEFER) defer = TRUE;
2673 } /* continue with next keystring domain/address */
2675 if (defer) return DEFER;
2677 } /* continue with next dnsdb outer domain */
2682 /* End of verify.c */