1 /* $Cambridge: exim/src/src/verify.c,v 1.30 2005/12/06 10:25:59 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 *save_deliver_domain = deliver_domain;
156 uschar **failure_ptr = is_recipient?
157 &recipient_verify_failure : &sender_verify_failure;
159 open_db *dbm_file = NULL;
160 dbdata_callout_cache new_domain_record;
161 dbdata_callout_cache_address new_address_record;
163 time_t callout_start_time;
165 new_domain_record.result = ccache_unknown;
166 new_domain_record.postmaster_result = ccache_unknown;
167 new_domain_record.random_result = ccache_unknown;
169 memset(&new_address_record, 0, sizeof(new_address_record));
171 /* For a recipient callout, the key used for the address cache record must
172 include the sender address if we are using the real sender in the callout,
173 because that may influence the result of the callout. */
175 address_key = addr->address;
180 if ((options & vopt_callout_recipsender) != 0)
182 address_key = string_sprintf("%s/<%s>", addr->address, sender_address);
183 from_address = sender_address;
185 else if ((options & vopt_callout_recippmaster) != 0)
187 address_key = string_sprintf("%s/<postmaster@%s>", addr->address,
188 qualify_domain_sender);
189 from_address = string_sprintf("postmaster@%s", qualify_domain_sender);
193 /* For a sender callout, we must adjust the key if the mailfrom address is not
198 from_address = (se_mailfrom == NULL)? US"" : se_mailfrom;
199 if (from_address[0] != 0)
200 address_key = string_sprintf("%s/<%s>", addr->address, from_address);
203 /* Open the callout cache database, it it exists, for reading only at this
204 stage, unless caching has been disabled. */
206 if (callout_no_cache)
208 HDEBUG(D_verify) debug_printf("callout cache: disabled by no_cache\n");
210 else if ((dbm_file = dbfn_open(US"callout", O_RDWR, &dbblock, FALSE)) == NULL)
212 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
215 /* If a cache database is available see if we can avoid the need to do an
216 actual callout by making use of previously-obtained data. */
218 if (dbm_file != NULL)
220 dbdata_callout_cache_address *cache_address_record;
221 dbdata_callout_cache *cache_record = get_callout_cache_record(dbm_file,
222 addr->domain, US"domain",
223 callout_cache_domain_positive_expire,
224 callout_cache_domain_negative_expire);
226 /* If an unexpired cache record was found for this domain, see if the callout
227 process can be short-circuited. */
229 if (cache_record != NULL)
231 /* If an early command (up to and including MAIL FROM:<>) was rejected,
232 there is no point carrying on. The callout fails. */
234 if (cache_record->result == ccache_reject)
236 setflag(addr, af_verify_nsfail);
238 debug_printf("callout cache: domain gave initial rejection, or "
239 "does not accept HELO or MAIL FROM:<>\n");
240 setflag(addr, af_verify_nsfail);
241 addr->user_message = US"(result of an earlier callout reused).";
243 *failure_ptr = US"mail";
247 /* If a previous check on a "random" local part was accepted, we assume
248 that the server does not do any checking on local parts. There is therefore
249 no point in doing the callout, because it will always be successful. If a
250 random check previously failed, arrange not to do it again, but preserve
251 the data in the new record. If a random check is required but hasn't been
252 done, skip the remaining cache processing. */
254 if (callout_random) switch(cache_record->random_result)
258 debug_printf("callout cache: domain accepts random addresses\n");
259 goto END_CALLOUT; /* Default yield is OK */
263 debug_printf("callout cache: domain rejects random addresses\n");
264 callout_random = FALSE;
265 new_domain_record.random_result = ccache_reject;
266 new_domain_record.random_stamp = cache_record->random_stamp;
271 debug_printf("callout cache: need to check random address handling "
272 "(not cached or cache expired)\n");
276 /* If a postmaster check is requested, but there was a previous failure,
277 there is again no point in carrying on. If a postmaster check is required,
278 but has not been done before, we are going to have to do a callout, so skip
279 remaining cache processing. */
281 if (pm_mailfrom != NULL)
283 if (cache_record->postmaster_result == ccache_reject)
285 setflag(addr, af_verify_pmfail);
287 debug_printf("callout cache: domain does not accept "
288 "RCPT TO:<postmaster@domain>\n");
290 *failure_ptr = US"postmaster";
291 setflag(addr, af_verify_pmfail);
292 addr->user_message = US"(result of earlier verification reused).";
295 if (cache_record->postmaster_result == ccache_unknown)
298 debug_printf("callout cache: need to check RCPT "
299 "TO:<postmaster@domain> (not cached or cache expired)\n");
303 /* If cache says OK, set pm_mailfrom NULL to prevent a redundant
304 postmaster check if the address itself has to be checked. Also ensure
305 that the value in the cache record is preserved (with its old timestamp).
308 HDEBUG(D_verify) debug_printf("callout cache: domain accepts RCPT "
309 "TO:<postmaster@domain>\n");
311 new_domain_record.postmaster_result = ccache_accept;
312 new_domain_record.postmaster_stamp = cache_record->postmaster_stamp;
316 /* We can't give a result based on information about the domain. See if there
317 is an unexpired cache record for this specific address (combined with the
318 sender address if we are doing a recipient callout with a non-empty sender).
321 cache_address_record = (dbdata_callout_cache_address *)
322 get_callout_cache_record(dbm_file,
323 address_key, US"address",
324 callout_cache_positive_expire,
325 callout_cache_negative_expire);
327 if (cache_address_record != NULL)
329 if (cache_address_record->result == ccache_accept)
332 debug_printf("callout cache: address record is positive\n");
337 debug_printf("callout cache: address record is negative\n");
338 addr->user_message = US"Previous (cached) callout verification failure";
339 *failure_ptr = US"recipient";
345 /* Close the cache database while we actually do the callout for real. */
348 dbfn_close(dbm_file);
352 /* The information wasn't available in the cache, so we have to do a real
353 callout and save the result in the cache for next time, unless no_cache is set,
354 or unless we have a previously cached negative random result. If we are to test
355 with a random local part, ensure that such a local part is available. If not,
356 log the fact, but carry on without randomming. */
358 if (callout_random && callout_random_local_part != NULL)
360 random_local_part = expand_string(callout_random_local_part);
361 if (random_local_part == NULL)
362 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand "
363 "callout_random_local_part: %s", expand_string_message);
366 /* Default the connect and overall callout timeouts if not set, and record the
367 time we are starting so that we can enforce it. */
369 if (callout_overall < 0) callout_overall = 4 * callout;
370 if (callout_connect < 0) callout_connect = callout;
371 callout_start_time = time(NULL);
373 /* Now make connections to the hosts and do real callouts. The list of hosts
374 is passed in as an argument. */
376 for (host = host_list; host != NULL && !done; host = host->next)
378 smtp_inblock inblock;
379 smtp_outblock outblock;
382 BOOL send_quit = TRUE;
383 uschar *helo = US"HELO";
384 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
385 uschar inbuffer[4096];
386 uschar outbuffer[1024];
387 uschar responsebuffer[4096];
389 clearflag(addr, af_verify_pmfail); /* postmaster callout flag */
390 clearflag(addr, af_verify_nsfail); /* null sender callout flag */
392 /* Skip this host if we don't have an IP address for it. */
394 if (host->address == NULL)
396 DEBUG(D_verify) debug_printf("no IP address for host name %s: skipping\n",
401 /* Check the overall callout timeout */
403 if (time(NULL) - callout_start_time >= callout_overall)
405 HDEBUG(D_verify) debug_printf("overall timeout for callout exceeded\n");
409 /* Set IPv4 or IPv6 */
411 host_af = (Ustrchr(host->address, ':') == NULL)? AF_INET:AF_INET6;
413 /* Expand and interpret the interface and port strings. The latter will not
414 be used if there is a host-specific port (e.g. from a manualroute router).
415 This has to be delayed till now, because they may expand differently for
416 different hosts. If there's a failure, log it, but carry on with the
419 deliver_host = host->name;
420 deliver_host_address = host->address;
421 deliver_domain = addr->domain;
423 if (!smtp_get_interface(tf->interface, host_af, addr, NULL, &interface,
425 !smtp_get_port(tf->port, addr, &port, US"callout"))
426 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
429 deliver_host = deliver_host_address = NULL;
430 deliver_domain = save_deliver_domain;
432 /* Set HELO string according to the protocol */
434 if (Ustrcmp(tf->protocol, "lmtp") == 0) helo = US"LHLO";
436 HDEBUG(D_verify) debug_printf("interface=%s port=%d\n", interface, port);
438 /* Set up the buffer for reading SMTP response packets. */
440 inblock.buffer = inbuffer;
441 inblock.buffersize = sizeof(inbuffer);
442 inblock.ptr = inbuffer;
443 inblock.ptrend = inbuffer;
445 /* Set up the buffer for holding SMTP commands while pipelining */
447 outblock.buffer = outbuffer;
448 outblock.buffersize = sizeof(outbuffer);
449 outblock.ptr = outbuffer;
450 outblock.cmd_count = 0;
451 outblock.authenticating = FALSE;
453 /* Connect to the host; on failure, just loop for the next one, but we
454 set the error for the last one. Use the callout_connect timeout. */
456 inblock.sock = outblock.sock =
457 smtp_connect(host, host_af, port, interface, callout_connect, TRUE);
458 if (inblock.sock < 0)
460 addr->message = string_sprintf("could not connect to %s [%s]: %s",
461 host->name, host->address, strerror(errno));
465 /* Wait for initial response, and then run the initial SMTP commands. The
466 smtp_write_command() function leaves its command in big_buffer. This is
467 used in error responses. Initialize it in case the connection is
470 Ustrcpy(big_buffer, "initial connection");
473 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
476 smtp_write_command(&outblock, FALSE, "%s %s\r\n", helo,
477 smtp_active_hostname) >= 0 &&
478 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
481 smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>\r\n",
482 from_address) >= 0 &&
483 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
486 /* If the host gave an initial error, or does not accept HELO or MAIL
487 FROM:<>, arrange to cache this information, but don't record anything for an
488 I/O error or a defer. Do not cache rejections when a non-empty sender has
489 been used, because that blocks the whole domain for all senders. */
493 *failure_ptr = US"mail";
494 if (errno == 0 && responsebuffer[0] == '5')
496 setflag(addr, af_verify_nsfail);
497 if (from_address[0] == 0) new_domain_record.result = ccache_reject;
501 /* Otherwise, proceed to check a "random" address (if required), then the
502 given address, and the postmaster address (if required). Between each check,
503 issue RSET, because some servers accept only one recipient after MAIL
508 new_domain_record.result = ccache_accept;
510 /* Do the random local part check first */
512 if (random_local_part != NULL)
514 uschar randombuffer[1024];
516 smtp_write_command(&outblock, FALSE,
517 "RCPT TO:<%.1000s@%.1000s>\r\n", random_local_part,
518 addr->domain) >= 0 &&
519 smtp_read_response(&inblock, randombuffer,
520 sizeof(randombuffer), '2', callout);
522 /* Remember when we last did a random test */
524 new_domain_record.random_stamp = time(NULL);
526 /* If accepted, we aren't going to do any further tests below. */
530 new_domain_record.random_result = ccache_accept;
533 /* Otherwise, cache a real negative response, and get back to the right
534 state to send RCPT. Unless there's some problem such as a dropped
535 connection, we expect to succeed, because the commands succeeded above. */
539 if (randombuffer[0] == '5')
540 new_domain_record.random_result = ccache_reject;
543 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
544 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
547 smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>\r\n",
548 from_address) >= 0 &&
549 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
552 else done = FALSE; /* Some timeout/connection problem */
555 /* If the host is accepting all local parts, as determined by the "random"
556 check, we don't need to waste time doing any further checking. */
558 if (new_domain_record.random_result != ccache_accept && done)
560 /* Get the rcpt_include_affixes flag from the transport if there is one,
561 but assume FALSE if there is not. */
564 smtp_write_command(&outblock, FALSE, "RCPT TO:<%.1000s>\r\n",
565 transport_rcpt_address(addr,
566 (addr->transport == NULL)? FALSE :
567 addr->transport->rcpt_include_affixes)) >= 0 &&
568 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
572 new_address_record.result = ccache_accept;
573 else if (errno == 0 && responsebuffer[0] == '5')
575 *failure_ptr = US"recipient";
576 new_address_record.result = ccache_reject;
579 /* Do postmaster check if requested; if a full check is required, we
580 check for RCPT TO:<postmaster> (no domain) in accordance with RFC 821. */
582 if (done && pm_mailfrom != NULL)
585 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
586 smtp_read_response(&inblock, responsebuffer,
587 sizeof(responsebuffer), '2', callout) &&
589 smtp_write_command(&outblock, FALSE,
590 "MAIL FROM:<%s>\r\n", pm_mailfrom) >= 0 &&
591 smtp_read_response(&inblock, responsebuffer,
592 sizeof(responsebuffer), '2', callout) &&
594 /* First try using the current domain */
597 smtp_write_command(&outblock, FALSE,
598 "RCPT TO:<postmaster@%.1000s>\r\n", addr->domain) >= 0 &&
599 smtp_read_response(&inblock, responsebuffer,
600 sizeof(responsebuffer), '2', callout)
605 /* If that doesn't work, and a full check is requested,
606 try without the domain. */
609 (options & vopt_callout_fullpm) != 0 &&
610 smtp_write_command(&outblock, FALSE,
611 "RCPT TO:<postmaster>\r\n") >= 0 &&
612 smtp_read_response(&inblock, responsebuffer,
613 sizeof(responsebuffer), '2', callout)
616 /* Sort out the cache record */
618 new_domain_record.postmaster_stamp = time(NULL);
621 new_domain_record.postmaster_result = ccache_accept;
622 else if (errno == 0 && responsebuffer[0] == '5')
624 *failure_ptr = US"postmaster";
625 setflag(addr, af_verify_pmfail);
626 new_domain_record.postmaster_result = ccache_reject;
629 } /* Random not accepted */
630 } /* MAIL FROM: accepted */
632 /* For any failure of the main check, other than a negative response, we just
633 close the connection and carry on. We can identify a negative response by the
634 fact that errno is zero. For I/O errors it will be non-zero
636 Set up different error texts for logging and for sending back to the caller
637 as an SMTP response. Log in all cases, using a one-line format. For sender
638 callouts, give a full response to the caller, but for recipient callouts,
639 don't give the IP address because this may be an internal host whose identity
640 is not to be widely broadcast. */
644 if (errno == ETIMEDOUT)
646 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
651 if (*responsebuffer == 0) Ustrcpy(responsebuffer, US"connection dropped");
654 string_sprintf("response to \"%s\" from %s [%s] was: %s",
655 big_buffer, host->name, host->address,
656 string_printing(responsebuffer));
658 addr->user_message = is_recipient?
659 string_sprintf("Callout verification failed:\n%s", responsebuffer)
661 string_sprintf("Called: %s\nSent: %s\nResponse: %s",
662 host->address, big_buffer, responsebuffer);
664 /* Hard rejection ends the process */
666 if (responsebuffer[0] == '5') /* Address rejected */
674 /* End the SMTP conversation and close the connection. */
676 if (send_quit) (void)smtp_write_command(&outblock, FALSE, "QUIT\r\n");
677 (void)close(inblock.sock);
678 } /* Loop through all hosts, while !done */
680 /* If we get here with done == TRUE, a successful callout happened, and yield
681 will be set OK or FAIL according to the response to the RCPT command.
682 Otherwise, we looped through the hosts but couldn't complete the business.
683 However, there may be domain-specific information to cache in both cases.
685 The value of the result field in the new_domain record is ccache_unknown if
686 there was an error before or with MAIL FROM:, and errno was not zero,
687 implying some kind of I/O error. We don't want to write the cache in that case.
688 Otherwise the value is ccache_accept or ccache_reject. */
690 if (!callout_no_cache && new_domain_record.result != ccache_unknown)
692 if ((dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE))
695 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
699 (void)dbfn_write(dbm_file, addr->domain, &new_domain_record,
700 (int)sizeof(dbdata_callout_cache));
701 HDEBUG(D_verify) debug_printf("wrote callout cache domain record:\n"
702 " result=%d postmaster=%d random=%d\n",
703 new_domain_record.result,
704 new_domain_record.postmaster_result,
705 new_domain_record.random_result);
709 /* If a definite result was obtained for the callout, cache it unless caching
714 if (!callout_no_cache && new_address_record.result != ccache_unknown)
716 if (dbm_file == NULL)
717 dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE);
718 if (dbm_file == NULL)
720 HDEBUG(D_verify) debug_printf("no callout cache available\n");
724 (void)dbfn_write(dbm_file, address_key, &new_address_record,
725 (int)sizeof(dbdata_callout_cache_address));
726 HDEBUG(D_verify) debug_printf("wrote %s callout cache address record\n",
727 (new_address_record.result == ccache_accept)? "positive" : "negative");
732 /* Failure to connect to any host, or any response other than 2xx or 5xx is a
733 temporary error. If there was only one host, and a response was received, leave
734 it alone if supplying details. Otherwise, give a generic response. */
738 uschar *dullmsg = string_sprintf("Could not complete %s verify callout",
739 is_recipient? "recipient" : "sender");
742 if (host_list->next != NULL || addr->message == NULL) addr->message = dullmsg;
744 addr->user_message = (!smtp_return_error_details)? dullmsg :
745 string_sprintf("%s for <%s>.\n"
746 "The mail server(s) for the domain may be temporarily unreachable, or\n"
747 "they may be permanently unreachable from this server. In the latter case,\n%s",
748 dullmsg, addr->address,
750 "the address will never be accepted."
752 "you need to change the address or create an MX record for its domain\n"
753 "if it is supposed to be generally accessible from the Internet.\n"
754 "Talk to your mail administrator for details.");
756 /* Force a specific error code */
758 addr->basic_errno = ERRNO_CALLOUTDEFER;
761 /* Come here from within the cache-reading code on fast-track exit. */
764 if (dbm_file != NULL) dbfn_close(dbm_file);
770 /*************************************************
771 * Copy error to toplevel address *
772 *************************************************/
774 /* This function is used when a verify fails or defers, to ensure that the
775 failure or defer information is in the original toplevel address. This applies
776 when an address is redirected to a single new address, and the failure or
777 deferral happens to the child address.
780 vaddr the verify address item
781 addr the final address item
784 Returns: the value of YIELD
788 copy_error(address_item *vaddr, address_item *addr, int yield)
792 vaddr->message = addr->message;
793 vaddr->user_message = addr->user_message;
794 vaddr->basic_errno = addr->basic_errno;
795 vaddr->more_errno = addr->more_errno;
803 /*************************************************
804 * Verify an email address *
805 *************************************************/
807 /* This function is used both for verification (-bv and at other times) and
808 address testing (-bt), which is indicated by address_test_mode being set.
811 vaddr contains the address to verify; the next field in this block
813 f if not NULL, write the result to this file
814 options various option bits:
815 vopt_fake_sender => this sender verify is not for the real
816 sender (it was verify=sender=xxxx or an address from a
817 header line) - rewriting must not change sender_address
818 vopt_is_recipient => this is a recipient address, otherwise
819 it's a sender address - this affects qualification and
820 rewriting and messages from callouts
821 vopt_qualify => qualify an unqualified address; else error
822 vopt_expn => called from SMTP EXPN command
823 vopt_success_on_redirect => when a new address is generated
824 the verification instantly succeeds
826 These ones are used by do_callout() -- the options variable
829 vopt_callout_fullpm => if postmaster check, do full one
830 vopt_callout_no_cache => don't use callout cache
831 vopt_callout_random => do the "random" thing
832 vopt_callout_recipsender => use real sender for recipient
833 vopt_callout_recippmaster => use postmaster for recipient
835 callout if > 0, specifies that callout is required, and gives timeout
836 for individual commands
837 callout_overall if > 0, gives overall timeout for the callout function;
838 if < 0, a default is used (see do_callout())
839 callout_connect the connection timeout for callouts
840 se_mailfrom when callout is requested to verify a sender, use this
841 in MAIL FROM; NULL => ""
842 pm_mailfrom when callout is requested, if non-NULL, do the postmaster
843 thing and use this as the sender address (may be "")
845 routed if not NULL, set TRUE if routing succeeded, so we can
846 distinguish between routing failed and callout failed
848 Returns: OK address verified
849 FAIL address failed to verify
850 DEFER can't tell at present
854 verify_address(address_item *vaddr, FILE *f, int options, int callout,
855 int callout_overall, int callout_connect, uschar *se_mailfrom,
856 uschar *pm_mailfrom, BOOL *routed)
859 BOOL full_info = (f == NULL)? FALSE : (debug_selector != 0);
860 BOOL is_recipient = (options & vopt_is_recipient) != 0;
861 BOOL expn = (options & vopt_expn) != 0;
862 BOOL success_on_redirect = (options & vopt_success_on_redirect) != 0;
865 int verify_type = expn? v_expn :
866 address_test_mode? v_none :
867 is_recipient? v_recipient : v_sender;
868 address_item *addr_list;
869 address_item *addr_new = NULL;
870 address_item *addr_remote = NULL;
871 address_item *addr_local = NULL;
872 address_item *addr_succeed = NULL;
873 uschar **failure_ptr = is_recipient?
874 &recipient_verify_failure : &sender_verify_failure;
875 uschar *ko_prefix, *cr;
876 uschar *address = vaddr->address;
878 uschar null_sender[] = { 0 }; /* Ensure writeable memory */
880 /* Clear, just in case */
884 /* Set up a prefix and suffix for error message which allow us to use the same
885 output statements both in EXPN mode (where an SMTP response is needed) and when
886 debugging with an output file. */
890 ko_prefix = US"553 ";
893 else ko_prefix = cr = US"";
895 /* Add qualify domain if permitted; otherwise an unqualified address fails. */
897 if (parse_find_at(address) == NULL)
899 if ((options & vopt_qualify) == 0)
902 fprintf(f, "%sA domain is required for \"%s\"%s\n", ko_prefix, address,
904 *failure_ptr = US"qualify";
907 address = rewrite_address_qualify(address, is_recipient);
912 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
913 debug_printf("%s %s\n", address_test_mode? "Testing" : "Verifying", address);
916 /* Rewrite and report on it. Clear the domain and local part caches - these
917 may have been set by domains and local part tests during an ACL. */
919 if (global_rewrite_rules != NULL)
921 uschar *old = address;
922 address = rewrite_address(address, is_recipient, FALSE,
923 global_rewrite_rules, rewrite_existflags);
926 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->localpart_cache[i] = 0;
927 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->domain_cache[i] = 0;
928 if (f != NULL && !expn) fprintf(f, "Address rewritten as: %s\n", address);
932 /* If this is the real sender address, we must update sender_address at
933 this point, because it may be referred to in the routers. */
935 if ((options & (vopt_fake_sender|vopt_is_recipient)) == 0)
936 sender_address = address;
938 /* If the address was rewritten to <> no verification can be done, and we have
939 to return OK. This rewriting is permitted only for sender addresses; for other
940 addresses, such rewriting fails. */
942 if (address[0] == 0) return OK;
944 /* Save a copy of the sender address for re-instating if we change it to <>
945 while verifying a sender address (a nice bit of self-reference there). */
947 save_sender = sender_address;
949 /* Update the address structure with the possibly qualified and rewritten
950 address. Set it up as the starting address on the chain of new addresses. */
952 vaddr->address = address;
955 /* We need a loop, because an address can generate new addresses. We must also
956 cope with generated pipes and files at the top level. (See also the code and
957 comment in deliver.c.) However, it is usually the case that the router for
958 user's .forward files has its verify flag turned off.
960 If an address generates more than one child, the loop is used only when
961 full_info is set, and this can only be set locally. Remote enquiries just get
962 information about the top level address, not anything that it generated. */
964 while (addr_new != NULL)
967 address_item *addr = addr_new;
969 addr_new = addr->next;
974 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
975 debug_printf("Considering %s\n", addr->address);
978 /* Handle generated pipe, file or reply addresses. We don't get these
979 when handling EXPN, as it does only one level of expansion. */
981 if (testflag(addr, af_pfr))
988 if (addr->address[0] == '>')
990 allow = testflag(addr, af_allow_reply);
991 fprintf(f, "%s -> mail %s", addr->parent->address, addr->address + 1);
995 allow = (addr->address[0] == '|')?
996 testflag(addr, af_allow_pipe) : testflag(addr, af_allow_file);
997 fprintf(f, "%s -> %s", addr->parent->address, addr->address);
1000 if (addr->basic_errno == ERRNO_BADTRANSPORT)
1001 fprintf(f, "\n*** Error in setting up pipe, file, or autoreply:\n"
1002 "%s\n", addr->message);
1004 fprintf(f, "\n transport = %s\n", addr->transport->name);
1006 fprintf(f, " *** forbidden ***\n");
1011 /* Just in case some router parameter refers to it. */
1013 return_path = (addr->p.errors_address != NULL)?
1014 addr->p.errors_address : sender_address;
1016 /* Split the address into domain and local part, handling the %-hack if
1017 necessary, and then route it. While routing a sender address, set
1018 $sender_address to <> because that is what it will be if we were trying to
1019 send a bounce to the sender. */
1021 if (routed != NULL) *routed = FALSE;
1022 if ((rc = deliver_split_address(addr)) == OK)
1024 if (!is_recipient) sender_address = null_sender;
1025 rc = route_address(addr, &addr_local, &addr_remote, &addr_new,
1026 &addr_succeed, verify_type);
1027 sender_address = save_sender; /* Put back the real sender */
1030 /* If routing an address succeeded, set the flag that remembers, for use when
1031 an ACL cached a sender verify (in case a callout fails). Then if routing set
1032 up a list of hosts or the transport has a host list, and the callout option
1033 is set, and we aren't in a host checking run, do the callout verification,
1034 and set another flag that notes that a callout happened. */
1038 if (routed != NULL) *routed = TRUE;
1041 host_item *host_list = addr->host_list;
1043 /* Default, if no remote transport, to NULL for the interface (=> any),
1044 "smtp" for the port, and "smtp" for the protocol. */
1046 transport_feedback tf = { NULL, US"smtp", US"smtp", NULL, FALSE, FALSE };
1048 /* If verification yielded a remote transport, we want to use that
1049 transport's options, so as to mimic what would happen if we were really
1050 sending a message to this address. */
1052 if (addr->transport != NULL && !addr->transport->info->local)
1054 (void)(addr->transport->setup)(addr->transport, addr, &tf, NULL);
1056 /* If the transport has hosts and the router does not, or if the
1057 transport is configured to override the router's hosts, we must build a
1058 host list of the transport's hosts, and find the IP addresses */
1060 if (tf.hosts != NULL && (host_list == NULL || tf.hosts_override))
1063 uschar *save_deliver_domain = deliver_domain;
1064 uschar *save_deliver_localpart = deliver_localpart;
1066 host_list = NULL; /* Ignore the router's hosts */
1068 deliver_domain = addr->domain;
1069 deliver_localpart = addr->local_part;
1070 s = expand_string(tf.hosts);
1071 deliver_domain = save_deliver_domain;
1072 deliver_localpart = save_deliver_localpart;
1076 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand list of hosts "
1077 "\"%s\" in %s transport for callout: %s", tf.hosts,
1078 addr->transport->name, expand_string_message);
1082 uschar *canonical_name;
1083 host_item *host, *nexthost;
1084 host_build_hostlist(&host_list, s, tf.hosts_randomize);
1086 /* Just ignore failures to find a host address. If we don't manage
1087 to find any addresses, the callout will defer. Note that more than
1088 one address may be found for a single host, which will result in
1089 additional host items being inserted into the chain. Hence we must
1090 save the next host first. */
1092 for (host = host_list; host != NULL; host = nexthost)
1094 nexthost = host->next;
1095 if (tf.gethostbyname ||
1096 string_is_ip_address(host->name, NULL) != 0)
1097 (void)host_find_byname(host, NULL, &canonical_name, TRUE);
1100 int flags = HOST_FIND_BY_A;
1101 if (tf.qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
1102 if (tf.search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
1103 (void)host_find_bydns(host, NULL, flags, NULL, NULL, NULL,
1104 &canonical_name, NULL);
1111 /* Can only do a callout if we have at least one host! If the callout
1112 fails, it will have set ${sender,recipient}_verify_failure. */
1114 if (host_list != NULL)
1116 HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n");
1117 if (host_checking && !host_checking_callout)
1120 debug_printf("... callout omitted by default when host testing\n"
1121 "(Use -bhc if you want the callouts to happen.)\n");
1125 rc = do_callout(addr, host_list, &tf, callout, callout_overall,
1126 callout_connect, options, se_mailfrom, pm_mailfrom);
1131 HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor "
1132 "transport provided a host list\n");
1137 /* Otherwise, any failure is a routing failure */
1139 else *failure_ptr = US"route";
1141 /* A router may return REROUTED if it has set up a child address as a result
1142 of a change of domain name (typically from widening). In this case we always
1143 want to continue to verify the new child. */
1145 if (rc == REROUTED) continue;
1147 /* Handle hard failures */
1154 fprintf(f, "%s%s %s", ko_prefix, address,
1155 address_test_mode? "is undeliverable" : "failed to verify");
1156 if (!expn && admin_user)
1158 if (addr->basic_errno > 0)
1159 fprintf(f, ": %s", strerror(addr->basic_errno));
1160 if (addr->message != NULL)
1161 fprintf(f, ":\n %s", addr->message);
1163 fprintf(f, "%s\n", cr);
1166 if (!full_info) return copy_error(vaddr, addr, FAIL);
1172 else if (rc == DEFER)
1177 fprintf(f, "%s%s cannot be resolved at this time", ko_prefix, address);
1178 if (!expn && admin_user)
1180 if (addr->basic_errno > 0)
1181 fprintf(f, ":\n %s", strerror(addr->basic_errno));
1182 if (addr->message != NULL)
1183 fprintf(f, ":\n %s", addr->message);
1184 else if (addr->basic_errno <= 0)
1185 fprintf(f, ":\n unknown error");
1188 fprintf(f, "%s\n", cr);
1190 if (!full_info) return copy_error(vaddr, addr, DEFER);
1191 else if (yield == OK) yield = DEFER;
1194 /* If we are handling EXPN, we do not want to continue to route beyond
1199 uschar *ok_prefix = US"250-";
1200 if (addr_new == NULL)
1202 if (addr_local == NULL && addr_remote == NULL)
1203 fprintf(f, "250 mail to <%s> is discarded\r\n", address);
1205 fprintf(f, "250 <%s>\r\n", address);
1207 else while (addr_new != NULL)
1209 address_item *addr2 = addr_new;
1210 addr_new = addr2->next;
1211 if (addr_new == NULL) ok_prefix = US"250 ";
1212 fprintf(f, "%s<%s>\r\n", ok_prefix, addr2->address);
1217 /* Successful routing other than EXPN. */
1221 /* Handle successful routing when short info wanted. Otherwise continue for
1222 other (generated) addresses. Short info is the operational case. Full info
1223 can be requested only when debug_selector != 0 and a file is supplied.
1225 There is a conflict between the use of aliasing as an alternate email
1226 address, and as a sort of mailing list. If an alias turns the incoming
1227 address into just one address (e.g. J.Caesar->jc44) you may well want to
1228 carry on verifying the generated address to ensure it is valid when
1229 checking incoming mail. If aliasing generates multiple addresses, you
1230 probably don't want to do this. Exim therefore treats the generation of
1231 just a single new address as a special case, and continues on to verify the
1232 generated address. */
1234 if (!full_info && /* Stop if short info wanted AND */
1235 (((addr_new == NULL || /* No new address OR */
1236 addr_new->next != NULL || /* More than one new address OR */
1237 testflag(addr_new, af_pfr))) /* New address is pfr */
1239 (addr_new != NULL && /* At least one new address AND */
1240 success_on_redirect))) /* success_on_redirect is set */
1242 if (f != NULL) fprintf(f, "%s %s\n", address,
1243 address_test_mode? "is deliverable" : "verified");
1245 /* If we have carried on to verify a child address, we want the value
1246 of $address_data to be that of the child */
1248 vaddr->p.address_data = addr->p.address_data;
1252 } /* Loop for generated addresses */
1254 /* Display the full results of the successful routing, including any generated
1255 addresses. Control gets here only when full_info is set, which requires f not
1256 to be NULL, and this occurs only when a top-level verify is called with the
1257 debugging switch on.
1259 If there are no local and no remote addresses, and there were no pipes, files,
1260 or autoreplies, and there were no errors or deferments, the message is to be
1261 discarded, usually because of the use of :blackhole: in an alias file. */
1263 if (allok && addr_local == NULL && addr_remote == NULL)
1264 fprintf(f, "mail to %s is discarded\n", address);
1266 else for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++)
1268 while (addr_list != NULL)
1270 address_item *addr = addr_list;
1271 address_item *p = addr->parent;
1272 addr_list = addr->next;
1274 fprintf(f, "%s", CS addr->address);
1275 #ifdef EXPERIMENTAL_SRS
1276 if(addr->p.srs_sender)
1277 fprintf(f, " [srs = %s]", addr->p.srs_sender);
1281 fprintf(f, "\n <-- %s", p->address);
1286 /* Show router, and transport */
1288 fprintf(f, "router = %s, ", addr->router->name);
1289 fprintf(f, "transport = %s\n", (addr->transport == NULL)? US"unset" :
1290 addr->transport->name);
1292 /* Show any hosts that are set up by a router unless the transport
1293 is going to override them; fiddle a bit to get a nice format. */
1295 if (addr->host_list != NULL && addr->transport != NULL &&
1296 !addr->transport->overrides_hosts)
1301 for (h = addr->host_list; h != NULL; h = h->next)
1303 int len = Ustrlen(h->name);
1304 if (len > maxlen) maxlen = len;
1305 len = (h->address != NULL)? Ustrlen(h->address) : 7;
1306 if (len > maxaddlen) maxaddlen = len;
1308 for (h = addr->host_list; h != NULL; h = h->next)
1310 int len = Ustrlen(h->name);
1311 fprintf(f, " host %s ", h->name);
1312 while (len++ < maxlen) fprintf(f, " ");
1313 if (h->address != NULL)
1315 fprintf(f, "[%s] ", h->address);
1316 len = Ustrlen(h->address);
1318 else if (!addr->transport->info->local) /* Omit [unknown] for local */
1320 fprintf(f, "[unknown] ");
1324 while (len++ < maxaddlen) fprintf(f," ");
1325 if (h->mx >= 0) fprintf(f, "MX=%d", h->mx);
1326 if (h->port != PORT_NONE) fprintf(f, " port=%d", h->port);
1327 if (h->status == hstatus_unusable) fprintf(f, " ** unusable **");
1334 /* Will be DEFER or FAIL if any one address has, only for full_info (which is
1335 the -bv or -bt case). */
1343 /*************************************************
1344 * Check headers for syntax errors *
1345 *************************************************/
1347 /* This function checks those header lines that contain addresses, and verifies
1348 that all the addresses therein are syntactially correct.
1351 msgptr where to put an error message
1358 verify_check_headers(uschar **msgptr)
1363 for (h = header_list; h != NULL; h = h->next)
1365 if (h->type != htype_from &&
1366 h->type != htype_reply_to &&
1367 h->type != htype_sender &&
1368 h->type != htype_to &&
1369 h->type != htype_cc &&
1370 h->type != htype_bcc)
1373 colon = Ustrchr(h->text, ':');
1375 while (isspace(*s)) s++;
1377 parse_allow_group = TRUE; /* Allow group syntax */
1379 /* Loop for multiple addresses in the header */
1383 uschar *ss = parse_find_address_end(s, FALSE);
1384 uschar *recipient, *errmess;
1385 int terminator = *ss;
1386 int start, end, domain;
1388 /* Temporarily terminate the string at this point, and extract the
1389 operative address within. */
1392 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
1395 /* Permit an unqualified address only if the message is local, or if the
1396 sending host is configured to be permitted to send them. */
1398 if (recipient != NULL && domain == 0)
1400 if (h->type == htype_from || h->type == htype_sender)
1402 if (!allow_unqualified_sender) recipient = NULL;
1406 if (!allow_unqualified_recipient) recipient = NULL;
1408 if (recipient == NULL) errmess = US"unqualified address not permitted";
1411 /* It's an error if no address could be extracted, except for the special
1412 case of an empty address. */
1414 if (recipient == NULL && Ustrcmp(errmess, "empty address") != 0)
1416 uschar *verb = US"is";
1420 /* Arrange not to include any white space at the end in the
1423 while (t > s && isspace(t[-1])) t--;
1425 /* Add the address which failed to the error message, since in a
1426 header with very many addresses it is sometimes hard to spot
1427 which one is at fault. However, limit the amount of address to
1428 quote - cases have been seen where, for example, a missing double
1429 quote in a humungous To: header creates an "address" that is longer
1430 than string_sprintf can handle. */
1439 *msgptr = string_printing(
1440 string_sprintf("%s: failing address in \"%.*s\" header %s: %.*s",
1441 errmess, colon - h->text, h->text, verb, len, s));
1446 /* Advance to the next address */
1448 s = ss + (terminator? 1:0);
1449 while (isspace(*s)) s++;
1450 } /* Next address */
1458 /*************************************************
1459 * Check for blind recipients *
1460 *************************************************/
1462 /* This function checks that every (envelope) recipient is mentioned in either
1463 the To: or Cc: header lines, thus detecting blind carbon copies.
1465 There are two ways of scanning that could be used: either scan the header lines
1466 and tick off the recipients, or scan the recipients and check the header lines.
1467 The original proposed patch did the former, but I have chosen to do the latter,
1468 because (a) it requires no memory and (b) will use fewer resources when there
1469 are many addresses in To: and/or Cc: and only one or two envelope recipients.
1472 Returns: OK if there are no blind recipients
1473 FAIL if there is at least one blind recipient
1477 verify_check_notblind(void)
1480 for (i = 0; i < recipients_count; i++)
1484 uschar *address = recipients_list[i].address;
1486 for (h = header_list; !found && h != NULL; h = h->next)
1490 if (h->type != htype_to && h->type != htype_cc) continue;
1492 colon = Ustrchr(h->text, ':');
1494 while (isspace(*s)) s++;
1496 parse_allow_group = TRUE; /* Allow group syntax */
1498 /* Loop for multiple addresses in the header */
1502 uschar *ss = parse_find_address_end(s, FALSE);
1503 uschar *recipient,*errmess;
1504 int terminator = *ss;
1505 int start, end, domain;
1507 /* Temporarily terminate the string at this point, and extract the
1508 operative address within. */
1511 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
1514 /* If we found a valid recipient that has a domain, compare it with the
1515 envelope recipient. Local parts are compared case-sensitively, domains
1516 case-insensitively. By comparing from the start with length "domain", we
1517 include the "@" at the end, which ensures that we are comparing the whole
1518 local part of each address. */
1520 if (recipient != NULL && domain != 0)
1522 found = Ustrncmp(recipient, address, domain) == 0 &&
1523 strcmpic(recipient + domain, address + domain) == 0;
1527 /* Advance to the next address */
1529 s = ss + (terminator? 1:0);
1530 while (isspace(*s)) s++;
1531 } /* Next address */
1532 } /* Next header (if found is false) */
1534 if (!found) return FAIL;
1535 } /* Next recipient */
1542 /*************************************************
1543 * Find if verified sender *
1544 *************************************************/
1546 /* Usually, just a single address is verified as the sender of the message.
1547 However, Exim can be made to verify other addresses as well (often related in
1548 some way), and this is useful in some environments. There may therefore be a
1549 chain of such addresses that have previously been tested. This function finds
1550 whether a given address is on the chain.
1552 Arguments: the address to be verified
1553 Returns: pointer to an address item, or NULL
1557 verify_checked_sender(uschar *sender)
1560 for (addr = sender_verified_list; addr != NULL; addr = addr->next)
1561 if (Ustrcmp(sender, addr->address) == 0) break;
1569 /*************************************************
1570 * Get valid header address *
1571 *************************************************/
1573 /* Scan the originator headers of the message, looking for an address that
1574 verifies successfully. RFC 822 says:
1576 o The "Sender" field mailbox should be sent notices of
1577 any problems in transport or delivery of the original
1578 messages. If there is no "Sender" field, then the
1579 "From" field mailbox should be used.
1581 o If the "Reply-To" field exists, then the reply should
1582 go to the addresses indicated in that field and not to
1583 the address(es) indicated in the "From" field.
1585 So we check a Sender field if there is one, else a Reply_to field, else a From
1586 field. As some strange messages may have more than one of these fields,
1587 especially if they are resent- fields, check all of them if there is more than
1591 user_msgptr points to where to put a user error message
1592 log_msgptr points to where to put a log error message
1593 callout timeout for callout check (passed to verify_address())
1594 callout_overall overall callout timeout (ditto)
1595 callout_connect connect callout timeout (ditto)
1596 se_mailfrom mailfrom for verify; NULL => ""
1597 pm_mailfrom sender for pm callout check (passed to verify_address())
1598 options callout options (passed to verify_address())
1599 verrno where to put the address basic_errno
1601 If log_msgptr is set to something without setting user_msgptr, the caller
1602 normally uses log_msgptr for both things.
1604 Returns: result of the verification attempt: OK, FAIL, or DEFER;
1605 FAIL is given if no appropriate headers are found
1609 verify_check_header_address(uschar **user_msgptr, uschar **log_msgptr,
1610 int callout, int callout_overall, int callout_connect, uschar *se_mailfrom,
1611 uschar *pm_mailfrom, int options, int *verrno)
1613 static int header_types[] = { htype_sender, htype_reply_to, htype_from };
1617 for (i = 0; i < 3; i++)
1620 for (h = header_list; h != NULL; h = h->next)
1622 int terminator, new_ok;
1623 uschar *s, *ss, *endname;
1625 if (h->type != header_types[i]) continue;
1626 s = endname = Ustrchr(h->text, ':') + 1;
1630 address_item *vaddr;
1632 while (isspace(*s) || *s == ',') s++;
1633 if (*s == 0) break; /* End of header */
1635 ss = parse_find_address_end(s, FALSE);
1637 /* The terminator is a comma or end of header, but there may be white
1638 space preceding it (including newline for the last address). Move back
1639 past any white space so we can check against any cached envelope sender
1640 address verifications. */
1642 while (isspace(ss[-1])) ss--;
1646 HDEBUG(D_verify) debug_printf("verifying %.*s header address %s\n",
1647 (int)(endname - h->text), h->text, s);
1649 /* See if we have already verified this address as an envelope sender,
1650 and if so, use the previous answer. */
1652 vaddr = verify_checked_sender(s);
1654 if (vaddr != NULL && /* Previously checked */
1655 (callout <= 0 || /* No callout needed; OR */
1656 vaddr->special_action > 256)) /* Callout was done */
1658 new_ok = vaddr->special_action & 255;
1659 HDEBUG(D_verify) debug_printf("previously checked as envelope sender\n");
1660 *ss = terminator; /* Restore shortened string */
1663 /* Otherwise we run the verification now. We must restore the shortened
1664 string before running the verification, so the headers are correct, in
1665 case there is any rewriting. */
1669 int start, end, domain;
1670 uschar *address = parse_extract_address(s, log_msgptr, &start,
1671 &end, &domain, FALSE);
1675 /* If verification failed because of a syntax error, fail this
1676 function, and ensure that the failing address gets added to the error
1679 if (address == NULL)
1682 if (*log_msgptr != NULL)
1684 while (ss > s && isspace(ss[-1])) ss--;
1685 *log_msgptr = string_sprintf("syntax error in '%.*s' header when "
1686 "scanning for sender: %s in \"%.*s\"",
1687 endname - h->text, h->text, *log_msgptr, ss - s, s);
1692 /* Else go ahead with the sender verification. But it isn't *the*
1693 sender of the message, so set vopt_fake_sender to stop sender_address
1694 being replaced after rewriting or qualification. */
1698 vaddr = deliver_make_addr(address, FALSE);
1699 new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender,
1700 callout, callout_overall, callout_connect, se_mailfrom,
1705 /* We now have the result, either newly found, or cached. If we are
1706 giving out error details, set a specific user error. This means that the
1707 last of these will be returned to the user if all three fail. We do not
1708 set a log message - the generic one below will be used. */
1712 *verrno = vaddr->basic_errno;
1713 if (smtp_return_error_details)
1715 *user_msgptr = string_sprintf("Rejected after DATA: "
1716 "could not verify \"%.*s\" header address\n%s: %s",
1717 endname - h->text, h->text, vaddr->address, vaddr->message);
1721 /* Success or defer */
1723 if (new_ok == OK) return OK;
1724 if (new_ok == DEFER) yield = DEFER;
1726 /* Move on to any more addresses in the header */
1733 if (yield == FAIL && *log_msgptr == NULL)
1734 *log_msgptr = US"there is no valid sender in any header line";
1736 if (yield == DEFER && *log_msgptr == NULL)
1737 *log_msgptr = US"all attempts to verify a sender in a header line deferred";
1745 /*************************************************
1746 * Get RFC 1413 identification *
1747 *************************************************/
1749 /* Attempt to get an id from the sending machine via the RFC 1413 protocol. If
1750 the timeout is set to zero, then the query is not done. There may also be lists
1751 of hosts and nets which are exempt. To guard against malefactors sending
1752 non-printing characters which could, for example, disrupt a message's headers,
1753 make sure the string consists of printing characters only.
1756 port the port to connect to; usually this is IDENT_PORT (113), but when
1757 running in the test harness with -bh a different value is used.
1761 Side effect: any received ident value is put in sender_ident (NULL otherwise)
1765 verify_get_ident(int port)
1767 int sock, host_af, qlen;
1768 int received_sender_port, received_interface_port, n;
1770 uschar buffer[2048];
1772 /* Default is no ident. Check whether we want to do an ident check for this
1775 sender_ident = NULL;
1776 if (rfc1413_query_timeout <= 0 || verify_check_host(&rfc1413_hosts) != OK)
1779 DEBUG(D_ident) debug_printf("doing ident callback\n");
1781 /* Set up a connection to the ident port of the remote host. Bind the local end
1782 to the incoming interface address. If the sender host address is an IPv6
1783 address, the incoming interface address will also be IPv6. */
1785 host_af = (Ustrchr(sender_host_address, ':') == NULL)? AF_INET : AF_INET6;
1786 sock = ip_socket(SOCK_STREAM, host_af);
1787 if (sock < 0) return;
1789 if (ip_bind(sock, host_af, interface_address, 0) < 0)
1791 DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n",
1796 if (ip_connect(sock, host_af, sender_host_address, port, rfc1413_query_timeout)
1799 if (errno == ETIMEDOUT && (log_extra_selector & LX_ident_timeout) != 0)
1801 log_write(0, LOG_MAIN, "ident connection to %s timed out",
1802 sender_host_address);
1806 DEBUG(D_ident) debug_printf("ident connection to %s failed: %s\n",
1807 sender_host_address, strerror(errno));
1812 /* Construct and send the query. */
1814 sprintf(CS buffer, "%d , %d\r\n", sender_host_port, interface_port);
1815 qlen = Ustrlen(buffer);
1816 if (send(sock, buffer, qlen, 0) < 0)
1818 DEBUG(D_ident) debug_printf("ident send failed: %s\n", strerror(errno));
1822 /* Read a response line. We put it into the rest of the buffer, using several
1823 recv() calls if necessary. */
1831 int size = sizeof(buffer) - (p - buffer);
1833 if (size <= 0) goto END_OFF; /* Buffer filled without seeing \n. */
1834 count = ip_recv(sock, p, size, rfc1413_query_timeout);
1835 if (count <= 0) goto END_OFF; /* Read error or EOF */
1837 /* Scan what we just read, to see if we have reached the terminating \r\n. Be
1838 generous, and accept a plain \n terminator as well. The only illegal
1841 for (pp = p; pp < p + count; pp++)
1843 if (*pp == 0) goto END_OFF; /* Zero octet not allowed */
1846 if (pp[-1] == '\r') pp--;
1848 goto GOT_DATA; /* Break out of both loops */
1852 /* Reached the end of the data without finding \n. Let the loop continue to
1853 read some more, if there is room. */
1860 /* We have received a line of data. Check it carefully. It must start with the
1861 same two port numbers that we sent, followed by data as defined by the RFC. For
1864 12345 , 25 : USERID : UNIX :root
1866 However, the amount of white space may be different to what we sent. In the
1867 "osname" field there may be several sub-fields, comma separated. The data we
1868 actually want to save follows the third colon. Some systems put leading spaces
1869 in it - we discard those. */
1871 if (sscanf(CS buffer + qlen, "%d , %d%n", &received_sender_port,
1872 &received_interface_port, &n) != 2 ||
1873 received_sender_port != sender_host_port ||
1874 received_interface_port != interface_port)
1877 p = buffer + qlen + n;
1878 while(isspace(*p)) p++;
1879 if (*p++ != ':') goto END_OFF;
1880 while(isspace(*p)) p++;
1881 if (Ustrncmp(p, "USERID", 6) != 0) goto END_OFF;
1883 while(isspace(*p)) p++;
1884 if (*p++ != ':') goto END_OFF;
1885 while (*p != 0 && *p != ':') p++;
1886 if (*p++ == 0) goto END_OFF;
1887 while(isspace(*p)) p++;
1888 if (*p == 0) goto END_OFF;
1890 /* The rest of the line is the data we want. We turn it into printing
1891 characters when we save it, so that it cannot mess up the format of any logging
1892 or Received: lines into which it gets inserted. We keep a maximum of 127
1895 sender_ident = string_printing(string_copyn(p, 127));
1896 DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident);
1906 /*************************************************
1907 * Match host to a single host-list item *
1908 *************************************************/
1910 /* This function compares a host (name or address) against a single item
1911 from a host list. The host name gets looked up if it is needed and is not
1912 already known. The function is called from verify_check_this_host() via
1913 match_check_list(), which is why most of its arguments are in a single block.
1916 arg the argument block (see below)
1917 ss the host-list item
1918 valueptr where to pass back looked up data, or NULL
1919 error for error message when returning ERROR
1922 host_name (a) the host name, or
1923 (b) NULL, implying use sender_host_name and
1924 sender_host_aliases, looking them up if required, or
1925 (c) the empty string, meaning that only IP address matches
1927 host_address the host address
1928 host_ipv4 the IPv4 address taken from an IPv6 one
1932 DEFER lookup deferred
1933 ERROR (a) failed to find the host name or IP address, or
1934 (b) unknown lookup type specified, or
1935 (c) host name encountered when only IP addresses are
1940 check_host(void *arg, uschar *ss, uschar **valueptr, uschar **error)
1942 check_host_block *cb = (check_host_block *)arg;
1945 BOOL iplookup = FALSE;
1946 BOOL isquery = FALSE;
1947 BOOL isiponly = cb->host_name != NULL && cb->host_name[0] == 0;
1952 /* Optimize for the special case when the pattern is "*". */
1954 if (*ss == '*' && ss[1] == 0) return OK;
1956 /* If the pattern is empty, it matches only in the case when there is no host -
1957 this can occur in ACL checking for SMTP input using the -bs option. In this
1958 situation, the host address is the empty string. */
1960 if (cb->host_address[0] == 0) return (*ss == 0)? OK : FAIL;
1961 if (*ss == 0) return FAIL;
1963 /* If the pattern is precisely "@" then match against the primary host name,
1964 provided that host name matching is permitted; if it's "@[]" match against the
1965 local host's IP addresses. */
1971 if (isiponly) return ERROR;
1972 ss = primary_hostname;
1974 else if (Ustrcmp(ss, "@[]") == 0)
1976 ip_address_item *ip;
1977 for (ip = host_find_interfaces(); ip != NULL; ip = ip->next)
1978 if (Ustrcmp(ip->address, cb->host_address) == 0) return OK;
1983 /* If the pattern is an IP address, optionally followed by a bitmask count, do
1984 a (possibly masked) comparision with the current IP address. */
1986 if (string_is_ip_address(ss, &maskoffset) != 0)
1987 return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL);
1989 /* See if there is a semicolon in the pattern */
1991 semicolon = Ustrchr(ss, ';');
1993 /* If we are doing an IP address only match, then all lookups must be IP
1994 address lookups, even if there is no "net-". */
1998 iplookup = semicolon != NULL;
2001 /* Otherwise, if the item is of the form net[n]-lookup;<file|query> then it is
2002 a lookup on a masked IP network, in textual form. We obey this code even if we
2003 have already set iplookup, so as to skip over the "net-" prefix and to set the
2004 mask length. The net- stuff really only applies to single-key lookups where the
2005 key is implicit. For query-style lookups the key is specified in the query.
2006 From release 4.30, the use of net- for query style is no longer needed, but we
2007 retain it for backward compatibility. */
2009 if (Ustrncmp(ss, "net", 3) == 0 && semicolon != NULL)
2012 for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0';
2013 if (mlen == 0 && t == ss+3) mlen = -1; /* No mask supplied */
2014 iplookup = (*t++ == '-');
2017 /* Do the IP address lookup if that is indeed what we have */
2025 uschar *filename, *key, *result;
2028 /* Find the search type */
2030 search_type = search_findtype(t, semicolon - t);
2032 if (search_type < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
2033 search_error_message);
2035 /* Adjust parameters for the type of lookup. For a query-style lookup, there
2036 is no file name, and the "key" is just the query. For query-style with a file
2037 name, we have to fish the file off the start of the query. For a single-key
2038 lookup, the key is the current IP address, masked appropriately, and
2039 reconverted to text form, with the mask appended. For IPv6 addresses, specify
2040 dot separators instead of colons. */
2042 if (mac_islookup(search_type, lookup_absfilequery))
2044 filename = semicolon + 1;
2046 while (*key != 0 && !isspace(*key)) key++;
2047 filename = string_copyn(filename, key - filename);
2048 while (isspace(*key)) key++;
2050 else if (mac_islookup(search_type, lookup_querystyle))
2053 key = semicolon + 1;
2057 insize = host_aton(cb->host_address, incoming);
2058 host_mask(insize, incoming, mlen);
2059 (void)host_nmtoa(insize, incoming, mlen, buffer, '.');
2061 filename = semicolon + 1;
2064 /* Now do the actual lookup; note that there is no search_close() because
2065 of the caching arrangements. */
2067 handle = search_open(filename, search_type, 0, NULL, NULL);
2068 if (handle == NULL) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
2069 search_error_message);
2070 result = search_find(handle, filename, key, -1, NULL, 0, 0, NULL);
2071 if (valueptr != NULL) *valueptr = result;
2072 return (result != NULL)? OK : search_find_defer? DEFER: FAIL;
2075 /* The pattern is not an IP address or network reference of any kind. That is,
2076 it is a host name pattern. If this is an IP only match, there's an error in the
2081 *error = US"cannot match host name in match_ip list";
2085 /* Check the characters of the pattern to see if they comprise only letters,
2086 digits, full stops, and hyphens (the constituents of domain names). Allow
2087 underscores, as they are all too commonly found. Sigh. Also, if
2088 allow_utf8_domains is set, allow top-bit characters. */
2090 for (t = ss; *t != 0; t++)
2091 if (!isalnum(*t) && *t != '.' && *t != '-' && *t != '_' &&
2092 (!allow_utf8_domains || *t < 128)) break;
2094 /* If the pattern is a complete domain name, with no fancy characters, look up
2095 its IP address and match against that. Note that a multi-homed host will add
2096 items to the chain. */
2106 rc = host_find_byname(&h, NULL, NULL, FALSE);
2107 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2110 for (hh = &h; hh != NULL; hh = hh->next)
2112 if (host_is_in_net(hh->address, cb->host_address, 0)) return OK;
2116 if (rc == HOST_FIND_AGAIN) return DEFER;
2117 *error = string_sprintf("failed to find IP address for %s", ss);
2121 /* Almost all subsequent comparisons require the host name, and can be done
2122 using the general string matching function. When this function is called for
2123 outgoing hosts, the name is always given explicitly. If it is NULL, it means we
2124 must use sender_host_name and its aliases, looking them up if necessary. */
2126 if (cb->host_name != NULL) /* Explicit host name given */
2127 return match_check_string(cb->host_name, ss, -1, TRUE, TRUE, TRUE,
2130 /* Host name not given; in principle we need the sender host name and its
2131 aliases. However, for query-style lookups, we do not need the name if the
2132 query does not contain $sender_host_name. From release 4.23, a reference to
2133 $sender_host_name causes it to be looked up, so we don't need to do the lookup
2136 if ((semicolon = Ustrchr(ss, ';')) != NULL)
2139 int partial, affixlen, starflags, id;
2142 id = search_findtype_partial(ss, &partial, &affix, &affixlen, &starflags);
2145 if (id < 0) /* Unknown lookup type */
2147 log_write(0, LOG_MAIN|LOG_PANIC, "%s in host list item \"%s\"",
2148 search_error_message, ss);
2151 isquery = mac_islookup(id, lookup_querystyle|lookup_absfilequery);
2156 switch(match_check_string(US"", ss, -1, TRUE, TRUE, TRUE, valueptr))
2159 case DEFER: return DEFER;
2160 default: return FAIL;
2164 /* Not a query-style lookup; must ensure the host name is present, and then we
2165 do a check on the name and all its aliases. */
2167 if (sender_host_name == NULL)
2169 HDEBUG(D_host_lookup)
2170 debug_printf("sender host name required, to match against %s\n", ss);
2171 if (host_lookup_failed || host_name_lookup() != OK)
2173 *error = string_sprintf("failed to find host name for %s",
2174 sender_host_address);;
2177 host_build_sender_fullhost();
2180 /* Match on the sender host name, using the general matching function */
2182 switch(match_check_string(sender_host_name, ss, -1, TRUE, TRUE, TRUE,
2186 case DEFER: return DEFER;
2189 /* If there are aliases, try matching on them. */
2191 aliases = sender_host_aliases;
2192 while (*aliases != NULL)
2194 switch(match_check_string(*aliases++, ss, -1, TRUE, TRUE, TRUE, valueptr))
2197 case DEFER: return DEFER;
2206 /*************************************************
2207 * Check a specific host matches a host list *
2208 *************************************************/
2210 /* This function is passed a host list containing items in a number of
2211 different formats and the identity of a host. Its job is to determine whether
2212 the given host is in the set of hosts defined by the list. The host name is
2213 passed as a pointer so that it can be looked up if needed and not already
2214 known. This is commonly the case when called from verify_check_host() to check
2215 an incoming connection. When called from elsewhere the host name should usually
2218 This function is now just a front end to match_check_list(), which runs common
2219 code for scanning a list. We pass it the check_host() function to perform a
2223 listptr pointer to the host list
2224 cache_bits pointer to cache for named lists, or NULL
2225 host_name the host name or NULL, implying use sender_host_name and
2226 sender_host_aliases, looking them up if required
2227 host_address the IP address
2228 valueptr if not NULL, data from a lookup is passed back here
2230 Returns: OK if the host is in the defined set
2231 FAIL if the host is not in the defined set,
2232 DEFER if a data lookup deferred (not a host lookup)
2234 If the host name was needed in order to make a comparison, and could not be
2235 determined from the IP address, the result is FAIL unless the item
2236 "+allow_unknown" was met earlier in the list, in which case OK is returned. */
2239 verify_check_this_host(uschar **listptr, unsigned int *cache_bits,
2240 uschar *host_name, uschar *host_address, uschar **valueptr)
2243 unsigned int *local_cache_bits = cache_bits;
2244 uschar *save_host_address = deliver_host_address;
2245 check_host_block cb;
2246 cb.host_name = host_name;
2247 cb.host_address = host_address;
2249 if (valueptr != NULL) *valueptr = NULL;
2251 /* If the host address starts off ::ffff: it is an IPv6 address in
2252 IPv4-compatible mode. Find the IPv4 part for checking against IPv4
2255 cb.host_ipv4 = (Ustrncmp(host_address, "::ffff:", 7) == 0)?
2256 host_address + 7 : host_address;
2258 /* During the running of the check, put the IP address into $host_address. In
2259 the case of calls from the smtp transport, it will already be there. However,
2260 in other calls (e.g. when testing ignore_target_hosts), it won't. Just to be on
2261 the safe side, any existing setting is preserved, though as I write this
2262 (November 2004) I can't see any cases where it is actually needed. */
2264 deliver_host_address = host_address;
2265 rc = match_check_list(
2266 listptr, /* the list */
2267 0, /* separator character */
2268 &hostlist_anchor, /* anchor pointer */
2269 &local_cache_bits, /* cache pointer */
2270 check_host, /* function for testing */
2271 &cb, /* argument for function */
2272 MCL_HOST, /* type of check */
2273 (host_address == sender_host_address)?
2274 US"host" : host_address, /* text for debugging */
2275 valueptr); /* where to pass back data */
2276 deliver_host_address = save_host_address;
2283 /*************************************************
2284 * Check the remote host matches a list *
2285 *************************************************/
2287 /* This is a front end to verify_check_this_host(), created because checking
2288 the remote host is a common occurrence. With luck, a good compiler will spot
2289 the tail recursion and optimize it. If there's no host address, this is
2290 command-line SMTP input - check against an empty string for the address.
2293 listptr pointer to the host list
2295 Returns: the yield of verify_check_this_host(),
2296 i.e. OK, FAIL, or DEFER
2300 verify_check_host(uschar **listptr)
2302 return verify_check_this_host(listptr, sender_host_cache, NULL,
2303 (sender_host_address == NULL)? US"" : sender_host_address, NULL);
2310 /*************************************************
2311 * Invert an IP address for a DNS black list *
2312 *************************************************/
2316 buffer where to put the answer
2317 address the address to invert
2321 invert_address(uschar *buffer, uschar *address)
2324 uschar *bptr = buffer;
2326 /* If this is an IPv4 address mapped into IPv6 format, adjust the pointer
2327 to the IPv4 part only. */
2329 if (Ustrncmp(address, "::ffff:", 7) == 0) address += 7;
2331 /* Handle IPv4 address: when HAVE_IPV6 is false, the result of host_aton() is
2334 if (host_aton(address, bin) == 1)
2338 for (i = 0; i < 4; i++)
2340 sprintf(CS bptr, "%d.", x & 255);
2341 while (*bptr) bptr++;
2346 /* Handle IPv6 address. Actually, as far as I know, there are no IPv6 addresses
2347 in any DNS black lists, and the format in which they will be looked up is
2348 unknown. This is just a guess. */
2354 for (j = 3; j >= 0; j--)
2357 for (i = 0; i < 8; i++)
2359 sprintf(CS bptr, "%x.", x & 15);
2360 while (*bptr) bptr++;
2370 /*************************************************
2371 * Perform a single dnsbl lookup *
2372 *************************************************/
2374 /* This function is called from verify_check_dnsbl() below.
2377 domain the outer dnsbl domain (for debug message)
2378 keydomain the current keydomain (for debug message)
2379 query the domain to be looked up
2380 iplist the list of matching IP addresses
2381 bitmask true if bitmask matching is wanted
2382 invert_result true if result to be inverted
2383 defer_return what to return for a defer
2385 Returns: OK if lookup succeeded
2390 one_check_dnsbl(uschar *domain, uschar *keydomain, uschar *query,
2391 uschar *iplist, BOOL bitmask, BOOL invert_result, int defer_return)
2396 dnsbl_cache_block *cb;
2397 int old_pool = store_pool;
2399 /* Look for this query in the cache. */
2401 t = tree_search(dnsbl_cache, query);
2403 /* If not cached from a previous lookup, we must do a DNS lookup, and
2404 cache the result in permanent memory. */
2408 store_pool = POOL_PERM;
2410 /* Set up a tree entry to cache the lookup */
2412 t = store_get(sizeof(tree_node) + Ustrlen(query));
2413 Ustrcpy(t->name, query);
2414 t->data.ptr = cb = store_get(sizeof(dnsbl_cache_block));
2415 (void)tree_insertnode(&dnsbl_cache, t);
2417 /* Do the DNS loopup . */
2419 HDEBUG(D_dnsbl) debug_printf("new DNS lookup for %s\n", query);
2420 cb->rc = dns_basic_lookup(&dnsa, query, T_A);
2421 cb->text_set = FALSE;
2425 /* If the lookup succeeded, cache the RHS address. The code allows for
2426 more than one address - this was for complete generality and the possible
2427 use of A6 records. However, A6 records have been reduced to experimental
2428 status (August 2001) and may die out. So they may never get used at all,
2429 let alone in dnsbl records. However, leave the code here, just in case.
2431 Quite apart from one A6 RR generating multiple addresses, there are DNS
2432 lists that return more than one A record, so we must handle multiple
2433 addresses generated in that way as well. */
2435 if (cb->rc == DNS_SUCCEED)
2438 dns_address **addrp = &(cb->rhs);
2439 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2441 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
2443 if (rr->type == T_A)
2445 dns_address *da = dns_address_from_rr(&dnsa, rr);
2449 while (da->next != NULL) da = da->next;
2450 addrp = &(da->next);
2455 /* If we didn't find any A records, change the return code. This can
2456 happen when there is a CNAME record but there are no A records for what
2459 if (cb->rhs == NULL) cb->rc = DNS_NODATA;
2462 store_pool = old_pool;
2465 /* Previous lookup was cached */
2469 HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
2473 /* We now have the result of the DNS lookup, either newly done, or cached
2474 from a previous call. If the lookup succeeded, check against the address
2475 list if there is one. This may be a positive equality list (introduced by
2476 "="), a negative equality list (introduced by "!="), a positive bitmask
2477 list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/
2479 if (cb->rc == DNS_SUCCEED)
2481 dns_address *da = NULL;
2482 uschar *addlist = cb->rhs->address;
2484 /* For A and AAAA records, there may be multiple addresses from multiple
2485 records. For A6 records (currently not expected to be used) there may be
2486 multiple addresses from a single record. */
2488 for (da = cb->rhs->next; da != NULL; da = da->next)
2489 addlist = string_sprintf("%s, %s", addlist, da->address);
2491 HDEBUG(D_dnsbl) debug_printf("DNS lookup for %s succeeded (yielding %s)\n",
2494 /* Address list check; this can be either for equality, or via a bitmask.
2495 In the latter case, all the bits must match. */
2501 uschar *ptr = iplist;
2503 while (string_nextinlist(&ptr, &ipsep, ip, sizeof(ip)) != NULL)
2505 /* Handle exact matching */
2508 for (da = cb->rhs; da != NULL; da = da->next)
2510 if (Ustrcmp(CS da->address, ip) == 0) break;
2513 /* Handle bitmask matching */
2519 /* At present, all known DNS blocking lists use A records, with
2520 IPv4 addresses on the RHS encoding the information they return. I
2521 wonder if this will linger on as the last vestige of IPv4 when IPv6
2522 is ubiquitous? Anyway, for now we use paranoia code to completely
2523 ignore IPv6 addresses. The default mask is 0, which always matches.
2524 We change this only for IPv4 addresses in the list. */
2526 if (host_aton(ip, address) == 1) mask = address[0];
2528 /* Scan the returned addresses, skipping any that are IPv6 */
2530 for (da = cb->rhs; da != NULL; da = da->next)
2532 if (host_aton(da->address, address) != 1) continue;
2533 if ((address[0] & mask) == mask) break;
2537 /* Break out if a match has been found */
2539 if (da != NULL) break;
2544 (a) No IP address in a positive list matched, or
2545 (b) An IP address in a negative list did match
2547 then behave as if the DNSBL lookup had not succeeded, i.e. the host is
2550 if (invert_result != (da == NULL))
2554 debug_printf("=> but we are not accepting this block class because\n");
2555 debug_printf("=> there was %s match for %c%s\n",
2556 invert_result? "an exclude":"no", bitmask? '&' : '=', iplist);
2562 /* Either there was no IP list, or the record matched. Look up a TXT record
2563 if it hasn't previously been done. */
2567 cb->text_set = TRUE;
2568 if (dns_basic_lookup(&dnsa, query, T_TXT) == DNS_SUCCEED)
2571 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2573 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
2574 if (rr->type == T_TXT) break;
2577 int len = (rr->data)[0];
2578 if (len > 511) len = 127;
2579 store_pool = POOL_PERM;
2580 cb->text = string_sprintf("%.*s", len, (const uschar *)(rr->data+1));
2581 store_pool = old_pool;
2586 dnslist_value = addlist;
2587 dnslist_text = cb->text;
2591 /* There was a problem with the DNS lookup */
2593 if (cb->rc != DNS_NOMATCH && cb->rc != DNS_NODATA)
2595 log_write(L_dnslist_defer, LOG_MAIN,
2596 "DNS list lookup defer (probably timeout) for %s: %s", query,
2597 (defer_return == OK)? US"assumed in list" :
2598 (defer_return == FAIL)? US"assumed not in list" :
2599 US"returned DEFER");
2600 return defer_return;
2603 /* No entry was found in the DNS; continue for next domain */
2607 debug_printf("DNS lookup for %s failed\n", query);
2608 debug_printf("=> that means %s is not listed at %s\n",
2618 /*************************************************
2619 * Check host against DNS black lists *
2620 *************************************************/
2622 /* This function runs checks against a list of DNS black lists, until one
2623 matches. Each item on the list can be of the form
2625 domain=ip-address/key
2627 The domain is the right-most domain that is used for the query, for example,
2628 blackholes.mail-abuse.org. If the IP address is present, there is a match only
2629 if the DNS lookup returns a matching IP address. Several addresses may be
2630 given, comma-separated, for example: x.y.z=127.0.0.1,127.0.0.2.
2632 If no key is given, what is looked up in the domain is the inverted IP address
2633 of the current client host. If a key is given, it is used to construct the
2634 domain for the lookup. For example,
2636 dsn.rfc-ignorant.org/$sender_address_domain
2638 After finding a match in the DNS, the domain is placed in $dnslist_domain, and
2639 then we check for a TXT record for an error message, and if found, save its
2640 value in $dnslist_text. We also cache everything in a tree, to optimize
2643 Note: an address for testing RBL is 192.203.178.39
2644 Note: an address for testing DUL is 192.203.178.4
2645 Note: a domain for testing RFCI is example.tld.dsn.rfc-ignorant.org
2648 listptr the domain/address/data list
2650 Returns: OK successful lookup (i.e. the address is on the list), or
2651 lookup deferred after +include_unknown
2652 FAIL name not found, or no data found for the given type, or
2653 lookup deferred after +exclude_unknown (default)
2654 DEFER lookup failure, if +defer_unknown was set
2658 verify_check_dnsbl(uschar **listptr)
2661 int defer_return = FAIL;
2662 BOOL invert_result = FALSE;
2663 uschar *list = *listptr;
2666 uschar buffer[1024];
2667 uschar query[256]; /* DNS domain max length */
2668 uschar revadd[128]; /* Long enough for IPv6 address */
2670 /* Indicate that the inverted IP address is not yet set up */
2674 /* In case this is the first time the DNS resolver is being used. */
2676 dns_init(FALSE, FALSE);
2678 /* Loop through all the domains supplied, until something matches */
2680 while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
2684 BOOL bitmask = FALSE;
2688 HDEBUG(D_dnsbl) debug_printf("DNS list check: %s\n", domain);
2690 /* Deal with special values that change the behaviour on defer */
2692 if (domain[0] == '+')
2694 if (strcmpic(domain, US"+include_unknown") == 0) defer_return = OK;
2695 else if (strcmpic(domain, US"+exclude_unknown") == 0) defer_return = FAIL;
2696 else if (strcmpic(domain, US"+defer_unknown") == 0) defer_return = DEFER;
2698 log_write(0, LOG_MAIN|LOG_PANIC, "unknown item in dnslist (ignored): %s",
2703 /* See if there's explicit data to be looked up */
2705 key = Ustrchr(domain, '/');
2706 if (key != NULL) *key++ = 0;
2708 /* See if there's a list of addresses supplied after the domain name. This is
2709 introduced by an = or a & character; if preceded by ! we invert the result.
2712 iplist = Ustrchr(domain, '=');
2716 iplist = Ustrchr(domain, '&');
2721 if (iplist > domain && iplist[-1] == '!')
2723 invert_result = TRUE;
2729 /* Check that what we have left is a sensible domain name. There is no reason
2730 why these domains should in fact use the same syntax as hosts and email
2731 domains, but in practice they seem to. However, there is little point in
2732 actually causing an error here, because that would no doubt hold up incoming
2733 mail. Instead, I'll just log it. */
2735 for (s = domain; *s != 0; s++)
2737 if (!isalnum(*s) && *s != '-' && *s != '.')
2739 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
2740 "strange characters - is this right?", domain);
2745 /* If there is no key string, construct the query by adding the domain name
2746 onto the inverted host address, and perform a single DNS lookup. */
2750 if (sender_host_address == NULL) return FAIL; /* can never match */
2751 if (revadd[0] == 0) invert_address(revadd, sender_host_address);
2752 frc = string_format(query, sizeof(query), "%s%s", revadd, domain);
2756 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
2757 "(ignored): %s...", query);
2761 rc = one_check_dnsbl(domain, sender_host_address, query, iplist, bitmask,
2762 invert_result, defer_return);
2766 dnslist_domain = string_copy(domain);
2767 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
2768 sender_host_address, domain);
2771 if (rc != FAIL) return rc; /* OK or DEFER */
2774 /* If there is a key string, it can be a list of domains or IP addresses to
2775 be concatenated with the main domain. */
2782 uschar keybuffer[256];
2784 while ((keydomain = string_nextinlist(&key, &keysep, keybuffer,
2785 sizeof(keybuffer))) != NULL)
2787 if (string_is_ip_address(keydomain, NULL) != 0)
2789 uschar keyrevadd[128];
2790 invert_address(keyrevadd, keydomain);
2791 frc = string_format(query, sizeof(query), "%s%s", keyrevadd, domain);
2795 frc = string_format(query, sizeof(query), "%s.%s", keydomain, domain);
2800 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
2801 "(ignored): %s...", query);
2805 rc = one_check_dnsbl(domain, keydomain, query, iplist, bitmask,
2806 invert_result, defer_return);
2810 dnslist_domain = string_copy(domain);
2811 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
2816 /* If the lookup deferred, remember this fact. We keep trying the rest
2817 of the list to see if we get a useful result, and if we don't, we return
2818 DEFER at the end. */
2820 if (rc == DEFER) defer = TRUE;
2821 } /* continue with next keystring domain/address */
2823 if (defer) return DEFER;
2825 } /* continue with next dnsdb outer domain */
2830 /* End of verify.c */