1 /* $Cambridge: exim/src/src/verify.c,v 1.35 2006/03/16 12:07:55 ph10 Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2006 */
8 /* See the file NOTICE for conditions of use and distribution. */
10 /* Functions concerned with verifying things. The original code for callout
11 caching was contributed by Kevin Fleming (but I hacked it around a bit). */
17 /* Structure for caching DNSBL lookups */
19 typedef struct dnsbl_cache_block {
27 /* Anchor for DNSBL cache */
29 static tree_node *dnsbl_cache = NULL;
33 /*************************************************
34 * Retrieve a callout cache record *
35 *************************************************/
37 /* If a record exists, check whether it has expired.
40 dbm_file an open hints file
42 type "address" or "domain"
43 positive_expire expire time for positive records
44 negative_expire expire time for negative records
46 Returns: the cache record if a non-expired one exists, else NULL
49 static dbdata_callout_cache *
50 get_callout_cache_record(open_db *dbm_file, uschar *key, uschar *type,
51 int positive_expire, int negative_expire)
56 dbdata_callout_cache *cache_record;
58 cache_record = dbfn_read_with_length(dbm_file, key, &length);
60 if (cache_record == NULL)
62 HDEBUG(D_verify) debug_printf("callout cache: no %s record found\n", type);
66 /* We treat a record as "negative" if its result field is not positive, or if
67 it is a domain record and the postmaster field is negative. */
69 negative = cache_record->result != ccache_accept ||
70 (type[0] == 'd' && cache_record->postmaster_result == ccache_reject);
71 expire = negative? negative_expire : positive_expire;
74 if (now - cache_record->time_stamp > expire)
76 HDEBUG(D_verify) debug_printf("callout cache: %s record expired\n", type);
80 /* If this is a non-reject domain record, check for the obsolete format version
81 that doesn't have the postmaster and random timestamps, by looking at the
82 length. If so, copy it to a new-style block, replicating the record's
83 timestamp. Then check the additional timestamps. (There's no point wasting
84 effort if connections are rejected.) */
86 if (type[0] == 'd' && cache_record->result != ccache_reject)
88 if (length == sizeof(dbdata_callout_cache_obs))
90 dbdata_callout_cache *new = store_get(sizeof(dbdata_callout_cache));
91 memcpy(new, cache_record, length);
92 new->postmaster_stamp = new->random_stamp = new->time_stamp;
96 if (now - cache_record->postmaster_stamp > expire)
97 cache_record->postmaster_result = ccache_unknown;
99 if (now - cache_record->random_stamp > expire)
100 cache_record->random_result = ccache_unknown;
103 HDEBUG(D_verify) debug_printf("callout cache: found %s record\n", type);
109 /*************************************************
110 * Do callout verification for an address *
111 *************************************************/
113 /* This function is called from verify_address() when the address has routed to
114 a host list, and a callout has been requested. Callouts are expensive; that is
115 why a cache is used to improve the efficiency.
118 addr the address that's been routed
119 host_list the list of hosts to try
120 tf the transport feedback block
122 ifstring "interface" option from transport, or NULL
123 portstring "port" option from transport, or NULL
124 protocolstring "protocol" option from transport, or NULL
125 callout the per-command callout timeout
126 callout_overall the overall callout timeout (if < 0 use 4*callout)
127 callout_connect the callout connection timeout (if < 0 use callout)
128 options the verification options - these bits are used:
129 vopt_is_recipient => this is a recipient address
130 vopt_callout_no_cache => don't use callout cache
131 vopt_callout_fullpm => if postmaster check, do full one
132 vopt_callout_random => do the "random" thing
133 vopt_callout_recipsender => use real sender for recipient
134 vopt_callout_recippmaster => use postmaster for recipient
135 se_mailfrom MAIL FROM address for sender verify; NULL => ""
136 pm_mailfrom if non-NULL, do the postmaster check with this sender
138 Returns: OK/FAIL/DEFER
142 do_callout(address_item *addr, host_item *host_list, transport_feedback *tf,
143 int callout, int callout_overall, int callout_connect, int options,
144 uschar *se_mailfrom, uschar *pm_mailfrom)
146 BOOL is_recipient = (options & vopt_is_recipient) != 0;
147 BOOL callout_no_cache = (options & vopt_callout_no_cache) != 0;
148 BOOL callout_random = (options & vopt_callout_random) != 0;
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;
796 vaddr->p.address_data = addr->p.address_data;
804 /*************************************************
805 * Verify an email address *
806 *************************************************/
808 /* This function is used both for verification (-bv and at other times) and
809 address testing (-bt), which is indicated by address_test_mode being set.
812 vaddr contains the address to verify; the next field in this block
814 f if not NULL, write the result to this file
815 options various option bits:
816 vopt_fake_sender => this sender verify is not for the real
817 sender (it was verify=sender=xxxx or an address from a
818 header line) - rewriting must not change sender_address
819 vopt_is_recipient => this is a recipient address, otherwise
820 it's a sender address - this affects qualification and
821 rewriting and messages from callouts
822 vopt_qualify => qualify an unqualified address; else error
823 vopt_expn => called from SMTP EXPN command
824 vopt_success_on_redirect => when a new address is generated
825 the verification instantly succeeds
827 These ones are used by do_callout() -- the options variable
830 vopt_callout_fullpm => if postmaster check, do full one
831 vopt_callout_no_cache => don't use callout cache
832 vopt_callout_random => do the "random" thing
833 vopt_callout_recipsender => use real sender for recipient
834 vopt_callout_recippmaster => use postmaster for recipient
836 callout if > 0, specifies that callout is required, and gives timeout
837 for individual commands
838 callout_overall if > 0, gives overall timeout for the callout function;
839 if < 0, a default is used (see do_callout())
840 callout_connect the connection timeout for callouts
841 se_mailfrom when callout is requested to verify a sender, use this
842 in MAIL FROM; NULL => ""
843 pm_mailfrom when callout is requested, if non-NULL, do the postmaster
844 thing and use this as the sender address (may be "")
846 routed if not NULL, set TRUE if routing succeeded, so we can
847 distinguish between routing failed and callout failed
849 Returns: OK address verified
850 FAIL address failed to verify
851 DEFER can't tell at present
855 verify_address(address_item *vaddr, FILE *f, int options, int callout,
856 int callout_overall, int callout_connect, uschar *se_mailfrom,
857 uschar *pm_mailfrom, BOOL *routed)
860 BOOL full_info = (f == NULL)? FALSE : (debug_selector != 0);
861 BOOL is_recipient = (options & vopt_is_recipient) != 0;
862 BOOL expn = (options & vopt_expn) != 0;
863 BOOL success_on_redirect = (options & vopt_success_on_redirect) != 0;
866 int verify_type = expn? v_expn :
867 address_test_mode? v_none :
868 is_recipient? v_recipient : v_sender;
869 address_item *addr_list;
870 address_item *addr_new = NULL;
871 address_item *addr_remote = NULL;
872 address_item *addr_local = NULL;
873 address_item *addr_succeed = NULL;
874 uschar **failure_ptr = is_recipient?
875 &recipient_verify_failure : &sender_verify_failure;
876 uschar *ko_prefix, *cr;
877 uschar *address = vaddr->address;
879 uschar null_sender[] = { 0 }; /* Ensure writeable memory */
881 /* Clear, just in case */
885 /* Set up a prefix and suffix for error message which allow us to use the same
886 output statements both in EXPN mode (where an SMTP response is needed) and when
887 debugging with an output file. */
891 ko_prefix = US"553 ";
894 else ko_prefix = cr = US"";
896 /* Add qualify domain if permitted; otherwise an unqualified address fails. */
898 if (parse_find_at(address) == NULL)
900 if ((options & vopt_qualify) == 0)
903 fprintf(f, "%sA domain is required for \"%s\"%s\n", ko_prefix, address,
905 *failure_ptr = US"qualify";
908 address = rewrite_address_qualify(address, is_recipient);
913 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
914 debug_printf("%s %s\n", address_test_mode? "Testing" : "Verifying", address);
917 /* Rewrite and report on it. Clear the domain and local part caches - these
918 may have been set by domains and local part tests during an ACL. */
920 if (global_rewrite_rules != NULL)
922 uschar *old = address;
923 address = rewrite_address(address, is_recipient, FALSE,
924 global_rewrite_rules, rewrite_existflags);
927 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->localpart_cache[i] = 0;
928 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->domain_cache[i] = 0;
929 if (f != NULL && !expn) fprintf(f, "Address rewritten as: %s\n", address);
933 /* If this is the real sender address, we must update sender_address at
934 this point, because it may be referred to in the routers. */
936 if ((options & (vopt_fake_sender|vopt_is_recipient)) == 0)
937 sender_address = address;
939 /* If the address was rewritten to <> no verification can be done, and we have
940 to return OK. This rewriting is permitted only for sender addresses; for other
941 addresses, such rewriting fails. */
943 if (address[0] == 0) return OK;
945 /* Save a copy of the sender address for re-instating if we change it to <>
946 while verifying a sender address (a nice bit of self-reference there). */
948 save_sender = sender_address;
950 /* Update the address structure with the possibly qualified and rewritten
951 address. Set it up as the starting address on the chain of new addresses. */
953 vaddr->address = address;
956 /* We need a loop, because an address can generate new addresses. We must also
957 cope with generated pipes and files at the top level. (See also the code and
958 comment in deliver.c.) However, it is usually the case that the router for
959 user's .forward files has its verify flag turned off.
961 If an address generates more than one child, the loop is used only when
962 full_info is set, and this can only be set locally. Remote enquiries just get
963 information about the top level address, not anything that it generated. */
965 while (addr_new != NULL)
968 address_item *addr = addr_new;
970 addr_new = addr->next;
975 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
976 debug_printf("Considering %s\n", addr->address);
979 /* Handle generated pipe, file or reply addresses. We don't get these
980 when handling EXPN, as it does only one level of expansion. */
982 if (testflag(addr, af_pfr))
989 if (addr->address[0] == '>')
991 allow = testflag(addr, af_allow_reply);
992 fprintf(f, "%s -> mail %s", addr->parent->address, addr->address + 1);
996 allow = (addr->address[0] == '|')?
997 testflag(addr, af_allow_pipe) : testflag(addr, af_allow_file);
998 fprintf(f, "%s -> %s", addr->parent->address, addr->address);
1001 if (addr->basic_errno == ERRNO_BADTRANSPORT)
1002 fprintf(f, "\n*** Error in setting up pipe, file, or autoreply:\n"
1003 "%s\n", addr->message);
1005 fprintf(f, "\n transport = %s\n", addr->transport->name);
1007 fprintf(f, " *** forbidden ***\n");
1012 /* Just in case some router parameter refers to it. */
1014 return_path = (addr->p.errors_address != NULL)?
1015 addr->p.errors_address : sender_address;
1017 /* Split the address into domain and local part, handling the %-hack if
1018 necessary, and then route it. While routing a sender address, set
1019 $sender_address to <> because that is what it will be if we were trying to
1020 send a bounce to the sender. */
1022 if (routed != NULL) *routed = FALSE;
1023 if ((rc = deliver_split_address(addr)) == OK)
1025 if (!is_recipient) sender_address = null_sender;
1026 rc = route_address(addr, &addr_local, &addr_remote, &addr_new,
1027 &addr_succeed, verify_type);
1028 sender_address = save_sender; /* Put back the real sender */
1031 /* If routing an address succeeded, set the flag that remembers, for use when
1032 an ACL cached a sender verify (in case a callout fails). Then if routing set
1033 up a list of hosts or the transport has a host list, and the callout option
1034 is set, and we aren't in a host checking run, do the callout verification,
1035 and set another flag that notes that a callout happened. */
1039 if (routed != NULL) *routed = TRUE;
1042 host_item *host_list = addr->host_list;
1044 /* Default, if no remote transport, to NULL for the interface (=> any),
1045 "smtp" for the port, and "smtp" for the protocol. */
1047 transport_feedback tf = { NULL, US"smtp", US"smtp", NULL, FALSE, FALSE };
1049 /* If verification yielded a remote transport, we want to use that
1050 transport's options, so as to mimic what would happen if we were really
1051 sending a message to this address. */
1053 if (addr->transport != NULL && !addr->transport->info->local)
1055 (void)(addr->transport->setup)(addr->transport, addr, &tf, 0, 0, NULL);
1057 /* If the transport has hosts and the router does not, or if the
1058 transport is configured to override the router's hosts, we must build a
1059 host list of the transport's hosts, and find the IP addresses */
1061 if (tf.hosts != NULL && (host_list == NULL || tf.hosts_override))
1064 uschar *save_deliver_domain = deliver_domain;
1065 uschar *save_deliver_localpart = deliver_localpart;
1067 host_list = NULL; /* Ignore the router's hosts */
1069 deliver_domain = addr->domain;
1070 deliver_localpart = addr->local_part;
1071 s = expand_string(tf.hosts);
1072 deliver_domain = save_deliver_domain;
1073 deliver_localpart = save_deliver_localpart;
1077 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand list of hosts "
1078 "\"%s\" in %s transport for callout: %s", tf.hosts,
1079 addr->transport->name, expand_string_message);
1083 uschar *canonical_name;
1084 host_item *host, *nexthost;
1085 host_build_hostlist(&host_list, s, tf.hosts_randomize);
1087 /* Just ignore failures to find a host address. If we don't manage
1088 to find any addresses, the callout will defer. Note that more than
1089 one address may be found for a single host, which will result in
1090 additional host items being inserted into the chain. Hence we must
1091 save the next host first. */
1093 for (host = host_list; host != NULL; host = nexthost)
1095 nexthost = host->next;
1096 if (tf.gethostbyname ||
1097 string_is_ip_address(host->name, NULL) != 0)
1098 (void)host_find_byname(host, NULL, &canonical_name, TRUE);
1101 int flags = HOST_FIND_BY_A;
1102 if (tf.qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
1103 if (tf.search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
1104 (void)host_find_bydns(host, NULL, flags, NULL, NULL, NULL,
1105 &canonical_name, NULL);
1112 /* Can only do a callout if we have at least one host! If the callout
1113 fails, it will have set ${sender,recipient}_verify_failure. */
1115 if (host_list != NULL)
1117 HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n");
1118 if (host_checking && !host_checking_callout)
1121 debug_printf("... callout omitted by default when host testing\n"
1122 "(Use -bhc if you want the callouts to happen.)\n");
1126 rc = do_callout(addr, host_list, &tf, callout, callout_overall,
1127 callout_connect, options, se_mailfrom, pm_mailfrom);
1132 HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor "
1133 "transport provided a host list\n");
1138 /* Otherwise, any failure is a routing failure */
1140 else *failure_ptr = US"route";
1142 /* A router may return REROUTED if it has set up a child address as a result
1143 of a change of domain name (typically from widening). In this case we always
1144 want to continue to verify the new child. */
1146 if (rc == REROUTED) continue;
1148 /* Handle hard failures */
1155 fprintf(f, "%s%s %s", ko_prefix, address,
1156 address_test_mode? "is undeliverable" : "failed to verify");
1157 if (!expn && admin_user)
1159 if (addr->basic_errno > 0)
1160 fprintf(f, ": %s", strerror(addr->basic_errno));
1161 if (addr->message != NULL)
1162 fprintf(f, ":\n %s", addr->message);
1164 fprintf(f, "%s\n", cr);
1167 if (!full_info) return copy_error(vaddr, addr, FAIL);
1173 else if (rc == DEFER)
1178 fprintf(f, "%s%s cannot be resolved at this time", ko_prefix, address);
1179 if (!expn && admin_user)
1181 if (addr->basic_errno > 0)
1182 fprintf(f, ":\n %s", strerror(addr->basic_errno));
1183 if (addr->message != NULL)
1184 fprintf(f, ":\n %s", addr->message);
1185 else if (addr->basic_errno <= 0)
1186 fprintf(f, ":\n unknown error");
1189 fprintf(f, "%s\n", cr);
1191 if (!full_info) return copy_error(vaddr, addr, DEFER);
1192 else if (yield == OK) yield = DEFER;
1195 /* If we are handling EXPN, we do not want to continue to route beyond
1200 uschar *ok_prefix = US"250-";
1201 if (addr_new == NULL)
1203 if (addr_local == NULL && addr_remote == NULL)
1204 fprintf(f, "250 mail to <%s> is discarded\r\n", address);
1206 fprintf(f, "250 <%s>\r\n", address);
1208 else while (addr_new != NULL)
1210 address_item *addr2 = addr_new;
1211 addr_new = addr2->next;
1212 if (addr_new == NULL) ok_prefix = US"250 ";
1213 fprintf(f, "%s<%s>\r\n", ok_prefix, addr2->address);
1218 /* Successful routing other than EXPN. */
1222 /* Handle successful routing when short info wanted. Otherwise continue for
1223 other (generated) addresses. Short info is the operational case. Full info
1224 can be requested only when debug_selector != 0 and a file is supplied.
1226 There is a conflict between the use of aliasing as an alternate email
1227 address, and as a sort of mailing list. If an alias turns the incoming
1228 address into just one address (e.g. J.Caesar->jc44) you may well want to
1229 carry on verifying the generated address to ensure it is valid when
1230 checking incoming mail. If aliasing generates multiple addresses, you
1231 probably don't want to do this. Exim therefore treats the generation of
1232 just a single new address as a special case, and continues on to verify the
1233 generated address. */
1235 if (!full_info && /* Stop if short info wanted AND */
1236 (((addr_new == NULL || /* No new address OR */
1237 addr_new->next != NULL || /* More than one new address OR */
1238 testflag(addr_new, af_pfr))) /* New address is pfr */
1240 (addr_new != NULL && /* At least one new address AND */
1241 success_on_redirect))) /* success_on_redirect is set */
1243 if (f != NULL) fprintf(f, "%s %s\n", address,
1244 address_test_mode? "is deliverable" : "verified");
1246 /* If we have carried on to verify a child address, we want the value
1247 of $address_data to be that of the child */
1249 vaddr->p.address_data = addr->p.address_data;
1253 } /* Loop for generated addresses */
1255 /* Display the full results of the successful routing, including any generated
1256 addresses. Control gets here only when full_info is set, which requires f not
1257 to be NULL, and this occurs only when a top-level verify is called with the
1258 debugging switch on.
1260 If there are no local and no remote addresses, and there were no pipes, files,
1261 or autoreplies, and there were no errors or deferments, the message is to be
1262 discarded, usually because of the use of :blackhole: in an alias file. */
1264 if (allok && addr_local == NULL && addr_remote == NULL)
1265 fprintf(f, "mail to %s is discarded\n", address);
1267 else for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++)
1269 while (addr_list != NULL)
1271 address_item *addr = addr_list;
1272 address_item *p = addr->parent;
1273 addr_list = addr->next;
1275 fprintf(f, "%s", CS addr->address);
1276 #ifdef EXPERIMENTAL_SRS
1277 if(addr->p.srs_sender)
1278 fprintf(f, " [srs = %s]", addr->p.srs_sender);
1282 fprintf(f, "\n <-- %s", p->address);
1287 /* Show router, and transport */
1289 fprintf(f, "router = %s, ", addr->router->name);
1290 fprintf(f, "transport = %s\n", (addr->transport == NULL)? US"unset" :
1291 addr->transport->name);
1293 /* Show any hosts that are set up by a router unless the transport
1294 is going to override them; fiddle a bit to get a nice format. */
1296 if (addr->host_list != NULL && addr->transport != NULL &&
1297 !addr->transport->overrides_hosts)
1302 for (h = addr->host_list; h != NULL; h = h->next)
1304 int len = Ustrlen(h->name);
1305 if (len > maxlen) maxlen = len;
1306 len = (h->address != NULL)? Ustrlen(h->address) : 7;
1307 if (len > maxaddlen) maxaddlen = len;
1309 for (h = addr->host_list; h != NULL; h = h->next)
1311 int len = Ustrlen(h->name);
1312 fprintf(f, " host %s ", h->name);
1313 while (len++ < maxlen) fprintf(f, " ");
1314 if (h->address != NULL)
1316 fprintf(f, "[%s] ", h->address);
1317 len = Ustrlen(h->address);
1319 else if (!addr->transport->info->local) /* Omit [unknown] for local */
1321 fprintf(f, "[unknown] ");
1325 while (len++ < maxaddlen) fprintf(f," ");
1326 if (h->mx >= 0) fprintf(f, "MX=%d", h->mx);
1327 if (h->port != PORT_NONE) fprintf(f, " port=%d", h->port);
1328 if (h->status == hstatus_unusable) fprintf(f, " ** unusable **");
1335 /* Will be DEFER or FAIL if any one address has, only for full_info (which is
1336 the -bv or -bt case). */
1344 /*************************************************
1345 * Check headers for syntax errors *
1346 *************************************************/
1348 /* This function checks those header lines that contain addresses, and verifies
1349 that all the addresses therein are syntactially correct.
1352 msgptr where to put an error message
1359 verify_check_headers(uschar **msgptr)
1364 for (h = header_list; h != NULL; h = h->next)
1366 if (h->type != htype_from &&
1367 h->type != htype_reply_to &&
1368 h->type != htype_sender &&
1369 h->type != htype_to &&
1370 h->type != htype_cc &&
1371 h->type != htype_bcc)
1374 colon = Ustrchr(h->text, ':');
1376 while (isspace(*s)) s++;
1378 parse_allow_group = TRUE; /* Allow group syntax */
1380 /* Loop for multiple addresses in the header */
1384 uschar *ss = parse_find_address_end(s, FALSE);
1385 uschar *recipient, *errmess;
1386 int terminator = *ss;
1387 int start, end, domain;
1389 /* Temporarily terminate the string at this point, and extract the
1390 operative address within. */
1393 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
1396 /* Permit an unqualified address only if the message is local, or if the
1397 sending host is configured to be permitted to send them. */
1399 if (recipient != NULL && domain == 0)
1401 if (h->type == htype_from || h->type == htype_sender)
1403 if (!allow_unqualified_sender) recipient = NULL;
1407 if (!allow_unqualified_recipient) recipient = NULL;
1409 if (recipient == NULL) errmess = US"unqualified address not permitted";
1412 /* It's an error if no address could be extracted, except for the special
1413 case of an empty address. */
1415 if (recipient == NULL && Ustrcmp(errmess, "empty address") != 0)
1417 uschar *verb = US"is";
1422 /* Arrange not to include any white space at the end in the
1423 error message or the header name. */
1425 while (t > s && isspace(t[-1])) t--;
1426 while (tt > h->text && isspace(tt[-1])) tt--;
1428 /* Add the address that failed to the error message, since in a
1429 header with very many addresses it is sometimes hard to spot
1430 which one is at fault. However, limit the amount of address to
1431 quote - cases have been seen where, for example, a missing double
1432 quote in a humungous To: header creates an "address" that is longer
1433 than string_sprintf can handle. */
1442 *msgptr = string_printing(
1443 string_sprintf("%s: failing address in \"%.*s:\" header %s: %.*s",
1444 errmess, tt - h->text, h->text, verb, len, s));
1449 /* Advance to the next address */
1451 s = ss + (terminator? 1:0);
1452 while (isspace(*s)) s++;
1453 } /* Next address */
1461 /*************************************************
1462 * Check for blind recipients *
1463 *************************************************/
1465 /* This function checks that every (envelope) recipient is mentioned in either
1466 the To: or Cc: header lines, thus detecting blind carbon copies.
1468 There are two ways of scanning that could be used: either scan the header lines
1469 and tick off the recipients, or scan the recipients and check the header lines.
1470 The original proposed patch did the former, but I have chosen to do the latter,
1471 because (a) it requires no memory and (b) will use fewer resources when there
1472 are many addresses in To: and/or Cc: and only one or two envelope recipients.
1475 Returns: OK if there are no blind recipients
1476 FAIL if there is at least one blind recipient
1480 verify_check_notblind(void)
1483 for (i = 0; i < recipients_count; i++)
1487 uschar *address = recipients_list[i].address;
1489 for (h = header_list; !found && h != NULL; h = h->next)
1493 if (h->type != htype_to && h->type != htype_cc) continue;
1495 colon = Ustrchr(h->text, ':');
1497 while (isspace(*s)) s++;
1499 parse_allow_group = TRUE; /* Allow group syntax */
1501 /* Loop for multiple addresses in the header */
1505 uschar *ss = parse_find_address_end(s, FALSE);
1506 uschar *recipient,*errmess;
1507 int terminator = *ss;
1508 int start, end, domain;
1510 /* Temporarily terminate the string at this point, and extract the
1511 operative address within. */
1514 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
1517 /* If we found a valid recipient that has a domain, compare it with the
1518 envelope recipient. Local parts are compared case-sensitively, domains
1519 case-insensitively. By comparing from the start with length "domain", we
1520 include the "@" at the end, which ensures that we are comparing the whole
1521 local part of each address. */
1523 if (recipient != NULL && domain != 0)
1525 found = Ustrncmp(recipient, address, domain) == 0 &&
1526 strcmpic(recipient + domain, address + domain) == 0;
1530 /* Advance to the next address */
1532 s = ss + (terminator? 1:0);
1533 while (isspace(*s)) s++;
1534 } /* Next address */
1535 } /* Next header (if found is false) */
1537 if (!found) return FAIL;
1538 } /* Next recipient */
1545 /*************************************************
1546 * Find if verified sender *
1547 *************************************************/
1549 /* Usually, just a single address is verified as the sender of the message.
1550 However, Exim can be made to verify other addresses as well (often related in
1551 some way), and this is useful in some environments. There may therefore be a
1552 chain of such addresses that have previously been tested. This function finds
1553 whether a given address is on the chain.
1555 Arguments: the address to be verified
1556 Returns: pointer to an address item, or NULL
1560 verify_checked_sender(uschar *sender)
1563 for (addr = sender_verified_list; addr != NULL; addr = addr->next)
1564 if (Ustrcmp(sender, addr->address) == 0) break;
1572 /*************************************************
1573 * Get valid header address *
1574 *************************************************/
1576 /* Scan the originator headers of the message, looking for an address that
1577 verifies successfully. RFC 822 says:
1579 o The "Sender" field mailbox should be sent notices of
1580 any problems in transport or delivery of the original
1581 messages. If there is no "Sender" field, then the
1582 "From" field mailbox should be used.
1584 o If the "Reply-To" field exists, then the reply should
1585 go to the addresses indicated in that field and not to
1586 the address(es) indicated in the "From" field.
1588 So we check a Sender field if there is one, else a Reply_to field, else a From
1589 field. As some strange messages may have more than one of these fields,
1590 especially if they are resent- fields, check all of them if there is more than
1594 user_msgptr points to where to put a user error message
1595 log_msgptr points to where to put a log error message
1596 callout timeout for callout check (passed to verify_address())
1597 callout_overall overall callout timeout (ditto)
1598 callout_connect connect callout timeout (ditto)
1599 se_mailfrom mailfrom for verify; NULL => ""
1600 pm_mailfrom sender for pm callout check (passed to verify_address())
1601 options callout options (passed to verify_address())
1602 verrno where to put the address basic_errno
1604 If log_msgptr is set to something without setting user_msgptr, the caller
1605 normally uses log_msgptr for both things.
1607 Returns: result of the verification attempt: OK, FAIL, or DEFER;
1608 FAIL is given if no appropriate headers are found
1612 verify_check_header_address(uschar **user_msgptr, uschar **log_msgptr,
1613 int callout, int callout_overall, int callout_connect, uschar *se_mailfrom,
1614 uschar *pm_mailfrom, int options, int *verrno)
1616 static int header_types[] = { htype_sender, htype_reply_to, htype_from };
1620 for (i = 0; i < 3; i++)
1623 for (h = header_list; h != NULL; h = h->next)
1625 int terminator, new_ok;
1626 uschar *s, *ss, *endname;
1628 if (h->type != header_types[i]) continue;
1629 s = endname = Ustrchr(h->text, ':') + 1;
1633 address_item *vaddr;
1635 while (isspace(*s) || *s == ',') s++;
1636 if (*s == 0) break; /* End of header */
1638 ss = parse_find_address_end(s, FALSE);
1640 /* The terminator is a comma or end of header, but there may be white
1641 space preceding it (including newline for the last address). Move back
1642 past any white space so we can check against any cached envelope sender
1643 address verifications. */
1645 while (isspace(ss[-1])) ss--;
1649 HDEBUG(D_verify) debug_printf("verifying %.*s header address %s\n",
1650 (int)(endname - h->text), h->text, s);
1652 /* See if we have already verified this address as an envelope sender,
1653 and if so, use the previous answer. */
1655 vaddr = verify_checked_sender(s);
1657 if (vaddr != NULL && /* Previously checked */
1658 (callout <= 0 || /* No callout needed; OR */
1659 vaddr->special_action > 256)) /* Callout was done */
1661 new_ok = vaddr->special_action & 255;
1662 HDEBUG(D_verify) debug_printf("previously checked as envelope sender\n");
1663 *ss = terminator; /* Restore shortened string */
1666 /* Otherwise we run the verification now. We must restore the shortened
1667 string before running the verification, so the headers are correct, in
1668 case there is any rewriting. */
1672 int start, end, domain;
1673 uschar *address = parse_extract_address(s, log_msgptr, &start,
1674 &end, &domain, FALSE);
1678 /* If verification failed because of a syntax error, fail this
1679 function, and ensure that the failing address gets added to the error
1682 if (address == NULL)
1685 if (*log_msgptr != NULL)
1687 while (ss > s && isspace(ss[-1])) ss--;
1688 *log_msgptr = string_sprintf("syntax error in '%.*s' header when "
1689 "scanning for sender: %s in \"%.*s\"",
1690 endname - h->text, h->text, *log_msgptr, ss - s, s);
1695 /* Else go ahead with the sender verification. But it isn't *the*
1696 sender of the message, so set vopt_fake_sender to stop sender_address
1697 being replaced after rewriting or qualification. */
1701 vaddr = deliver_make_addr(address, FALSE);
1702 new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender,
1703 callout, callout_overall, callout_connect, se_mailfrom,
1708 /* We now have the result, either newly found, or cached. If we are
1709 giving out error details, set a specific user error. This means that the
1710 last of these will be returned to the user if all three fail. We do not
1711 set a log message - the generic one below will be used. */
1715 *verrno = vaddr->basic_errno;
1716 if (smtp_return_error_details)
1718 *user_msgptr = string_sprintf("Rejected after DATA: "
1719 "could not verify \"%.*s\" header address\n%s: %s",
1720 endname - h->text, h->text, vaddr->address, vaddr->message);
1724 /* Success or defer */
1726 if (new_ok == OK) return OK;
1727 if (new_ok == DEFER) yield = DEFER;
1729 /* Move on to any more addresses in the header */
1736 if (yield == FAIL && *log_msgptr == NULL)
1737 *log_msgptr = US"there is no valid sender in any header line";
1739 if (yield == DEFER && *log_msgptr == NULL)
1740 *log_msgptr = US"all attempts to verify a sender in a header line deferred";
1748 /*************************************************
1749 * Get RFC 1413 identification *
1750 *************************************************/
1752 /* Attempt to get an id from the sending machine via the RFC 1413 protocol. If
1753 the timeout is set to zero, then the query is not done. There may also be lists
1754 of hosts and nets which are exempt. To guard against malefactors sending
1755 non-printing characters which could, for example, disrupt a message's headers,
1756 make sure the string consists of printing characters only.
1759 port the port to connect to; usually this is IDENT_PORT (113), but when
1760 running in the test harness with -bh a different value is used.
1764 Side effect: any received ident value is put in sender_ident (NULL otherwise)
1768 verify_get_ident(int port)
1770 int sock, host_af, qlen;
1771 int received_sender_port, received_interface_port, n;
1773 uschar buffer[2048];
1775 /* Default is no ident. Check whether we want to do an ident check for this
1778 sender_ident = NULL;
1779 if (rfc1413_query_timeout <= 0 || verify_check_host(&rfc1413_hosts) != OK)
1782 DEBUG(D_ident) debug_printf("doing ident callback\n");
1784 /* Set up a connection to the ident port of the remote host. Bind the local end
1785 to the incoming interface address. If the sender host address is an IPv6
1786 address, the incoming interface address will also be IPv6. */
1788 host_af = (Ustrchr(sender_host_address, ':') == NULL)? AF_INET : AF_INET6;
1789 sock = ip_socket(SOCK_STREAM, host_af);
1790 if (sock < 0) return;
1792 if (ip_bind(sock, host_af, interface_address, 0) < 0)
1794 DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n",
1799 if (ip_connect(sock, host_af, sender_host_address, port, rfc1413_query_timeout)
1802 if (errno == ETIMEDOUT && (log_extra_selector & LX_ident_timeout) != 0)
1804 log_write(0, LOG_MAIN, "ident connection to %s timed out",
1805 sender_host_address);
1809 DEBUG(D_ident) debug_printf("ident connection to %s failed: %s\n",
1810 sender_host_address, strerror(errno));
1815 /* Construct and send the query. */
1817 sprintf(CS buffer, "%d , %d\r\n", sender_host_port, interface_port);
1818 qlen = Ustrlen(buffer);
1819 if (send(sock, buffer, qlen, 0) < 0)
1821 DEBUG(D_ident) debug_printf("ident send failed: %s\n", strerror(errno));
1825 /* Read a response line. We put it into the rest of the buffer, using several
1826 recv() calls if necessary. */
1834 int size = sizeof(buffer) - (p - buffer);
1836 if (size <= 0) goto END_OFF; /* Buffer filled without seeing \n. */
1837 count = ip_recv(sock, p, size, rfc1413_query_timeout);
1838 if (count <= 0) goto END_OFF; /* Read error or EOF */
1840 /* Scan what we just read, to see if we have reached the terminating \r\n. Be
1841 generous, and accept a plain \n terminator as well. The only illegal
1844 for (pp = p; pp < p + count; pp++)
1846 if (*pp == 0) goto END_OFF; /* Zero octet not allowed */
1849 if (pp[-1] == '\r') pp--;
1851 goto GOT_DATA; /* Break out of both loops */
1855 /* Reached the end of the data without finding \n. Let the loop continue to
1856 read some more, if there is room. */
1863 /* We have received a line of data. Check it carefully. It must start with the
1864 same two port numbers that we sent, followed by data as defined by the RFC. For
1867 12345 , 25 : USERID : UNIX :root
1869 However, the amount of white space may be different to what we sent. In the
1870 "osname" field there may be several sub-fields, comma separated. The data we
1871 actually want to save follows the third colon. Some systems put leading spaces
1872 in it - we discard those. */
1874 if (sscanf(CS buffer + qlen, "%d , %d%n", &received_sender_port,
1875 &received_interface_port, &n) != 2 ||
1876 received_sender_port != sender_host_port ||
1877 received_interface_port != interface_port)
1880 p = buffer + qlen + n;
1881 while(isspace(*p)) p++;
1882 if (*p++ != ':') goto END_OFF;
1883 while(isspace(*p)) p++;
1884 if (Ustrncmp(p, "USERID", 6) != 0) goto END_OFF;
1886 while(isspace(*p)) p++;
1887 if (*p++ != ':') goto END_OFF;
1888 while (*p != 0 && *p != ':') p++;
1889 if (*p++ == 0) goto END_OFF;
1890 while(isspace(*p)) p++;
1891 if (*p == 0) goto END_OFF;
1893 /* The rest of the line is the data we want. We turn it into printing
1894 characters when we save it, so that it cannot mess up the format of any logging
1895 or Received: lines into which it gets inserted. We keep a maximum of 127
1898 sender_ident = string_printing(string_copyn(p, 127));
1899 DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident);
1909 /*************************************************
1910 * Match host to a single host-list item *
1911 *************************************************/
1913 /* This function compares a host (name or address) against a single item
1914 from a host list. The host name gets looked up if it is needed and is not
1915 already known. The function is called from verify_check_this_host() via
1916 match_check_list(), which is why most of its arguments are in a single block.
1919 arg the argument block (see below)
1920 ss the host-list item
1921 valueptr where to pass back looked up data, or NULL
1922 error for error message when returning ERROR
1925 host_name (a) the host name, or
1926 (b) NULL, implying use sender_host_name and
1927 sender_host_aliases, looking them up if required, or
1928 (c) the empty string, meaning that only IP address matches
1930 host_address the host address
1931 host_ipv4 the IPv4 address taken from an IPv6 one
1935 DEFER lookup deferred
1936 ERROR (a) failed to find the host name or IP address, or
1937 (b) unknown lookup type specified, or
1938 (c) host name encountered when only IP addresses are
1943 check_host(void *arg, uschar *ss, uschar **valueptr, uschar **error)
1945 check_host_block *cb = (check_host_block *)arg;
1948 BOOL iplookup = FALSE;
1949 BOOL isquery = FALSE;
1950 BOOL isiponly = cb->host_name != NULL && cb->host_name[0] == 0;
1955 /* Optimize for the special case when the pattern is "*". */
1957 if (*ss == '*' && ss[1] == 0) return OK;
1959 /* If the pattern is empty, it matches only in the case when there is no host -
1960 this can occur in ACL checking for SMTP input using the -bs option. In this
1961 situation, the host address is the empty string. */
1963 if (cb->host_address[0] == 0) return (*ss == 0)? OK : FAIL;
1964 if (*ss == 0) return FAIL;
1966 /* If the pattern is precisely "@" then match against the primary host name,
1967 provided that host name matching is permitted; if it's "@[]" match against the
1968 local host's IP addresses. */
1974 if (isiponly) return ERROR;
1975 ss = primary_hostname;
1977 else if (Ustrcmp(ss, "@[]") == 0)
1979 ip_address_item *ip;
1980 for (ip = host_find_interfaces(); ip != NULL; ip = ip->next)
1981 if (Ustrcmp(ip->address, cb->host_address) == 0) return OK;
1986 /* If the pattern is an IP address, optionally followed by a bitmask count, do
1987 a (possibly masked) comparision with the current IP address. */
1989 if (string_is_ip_address(ss, &maskoffset) != 0)
1990 return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL);
1992 /* The pattern is not an IP address. A common error that people make is to omit
1993 one component of an IPv4 address, either by accident, or believing that, for
1994 example, 1.2.3/24 is the same as 1.2.3.0/24, or 1.2.3 is the same as 1.2.3.0,
1995 which it isn't. (Those applications that do accept 1.2.3 as an IP address
1996 interpret it as 1.2.0.3 because the final component becomes 16-bit - this is an
1997 ancient specification.) To aid in debugging these cases, we give a specific
1998 error if the pattern contains only digits and dots or contains a slash preceded
1999 only by digits and dots (a slash at the start indicates a file name and of
2000 course slashes may be present in lookups, but not preceded only by digits and
2003 for (t = ss; isdigit(*t) || *t == '.'; t++);
2004 if (*t == 0 || (*t == '/' && t != ss))
2006 *error = US"malformed IPv4 address or address mask";
2010 /* See if there is a semicolon in the pattern */
2012 semicolon = Ustrchr(ss, ';');
2014 /* If we are doing an IP address only match, then all lookups must be IP
2015 address lookups, even if there is no "net-". */
2019 iplookup = semicolon != NULL;
2022 /* Otherwise, if the item is of the form net[n]-lookup;<file|query> then it is
2023 a lookup on a masked IP network, in textual form. We obey this code even if we
2024 have already set iplookup, so as to skip over the "net-" prefix and to set the
2025 mask length. The net- stuff really only applies to single-key lookups where the
2026 key is implicit. For query-style lookups the key is specified in the query.
2027 From release 4.30, the use of net- for query style is no longer needed, but we
2028 retain it for backward compatibility. */
2030 if (Ustrncmp(ss, "net", 3) == 0 && semicolon != NULL)
2033 for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0';
2034 if (mlen == 0 && t == ss+3) mlen = -1; /* No mask supplied */
2035 iplookup = (*t++ == '-');
2039 /* Do the IP address lookup if that is indeed what we have */
2047 uschar *filename, *key, *result;
2050 /* Find the search type */
2052 search_type = search_findtype(t, semicolon - t);
2054 if (search_type < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
2055 search_error_message);
2057 /* Adjust parameters for the type of lookup. For a query-style lookup, there
2058 is no file name, and the "key" is just the query. For query-style with a file
2059 name, we have to fish the file off the start of the query. For a single-key
2060 lookup, the key is the current IP address, masked appropriately, and
2061 reconverted to text form, with the mask appended. For IPv6 addresses, specify
2062 dot separators instead of colons. */
2064 if (mac_islookup(search_type, lookup_absfilequery))
2066 filename = semicolon + 1;
2068 while (*key != 0 && !isspace(*key)) key++;
2069 filename = string_copyn(filename, key - filename);
2070 while (isspace(*key)) key++;
2072 else if (mac_islookup(search_type, lookup_querystyle))
2075 key = semicolon + 1;
2079 insize = host_aton(cb->host_address, incoming);
2080 host_mask(insize, incoming, mlen);
2081 (void)host_nmtoa(insize, incoming, mlen, buffer, '.');
2083 filename = semicolon + 1;
2086 /* Now do the actual lookup; note that there is no search_close() because
2087 of the caching arrangements. */
2089 handle = search_open(filename, search_type, 0, NULL, NULL);
2090 if (handle == NULL) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
2091 search_error_message);
2092 result = search_find(handle, filename, key, -1, NULL, 0, 0, NULL);
2093 if (valueptr != NULL) *valueptr = result;
2094 return (result != NULL)? OK : search_find_defer? DEFER: FAIL;
2097 /* The pattern is not an IP address or network reference of any kind. That is,
2098 it is a host name pattern. If this is an IP only match, there's an error in the
2103 *error = US"cannot match host name in match_ip list";
2107 /* Check the characters of the pattern to see if they comprise only letters,
2108 digits, full stops, and hyphens (the constituents of domain names). Allow
2109 underscores, as they are all too commonly found. Sigh. Also, if
2110 allow_utf8_domains is set, allow top-bit characters. */
2112 for (t = ss; *t != 0; t++)
2113 if (!isalnum(*t) && *t != '.' && *t != '-' && *t != '_' &&
2114 (!allow_utf8_domains || *t < 128)) break;
2116 /* If the pattern is a complete domain name, with no fancy characters, look up
2117 its IP address and match against that. Note that a multi-homed host will add
2118 items to the chain. */
2128 rc = host_find_byname(&h, NULL, NULL, FALSE);
2129 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2132 for (hh = &h; hh != NULL; hh = hh->next)
2134 if (host_is_in_net(hh->address, cb->host_address, 0)) return OK;
2138 if (rc == HOST_FIND_AGAIN) return DEFER;
2139 *error = string_sprintf("failed to find IP address for %s", ss);
2143 /* Almost all subsequent comparisons require the host name, and can be done
2144 using the general string matching function. When this function is called for
2145 outgoing hosts, the name is always given explicitly. If it is NULL, it means we
2146 must use sender_host_name and its aliases, looking them up if necessary. */
2148 if (cb->host_name != NULL) /* Explicit host name given */
2149 return match_check_string(cb->host_name, ss, -1, TRUE, TRUE, TRUE,
2152 /* Host name not given; in principle we need the sender host name and its
2153 aliases. However, for query-style lookups, we do not need the name if the
2154 query does not contain $sender_host_name. From release 4.23, a reference to
2155 $sender_host_name causes it to be looked up, so we don't need to do the lookup
2158 if ((semicolon = Ustrchr(ss, ';')) != NULL)
2161 int partial, affixlen, starflags, id;
2164 id = search_findtype_partial(ss, &partial, &affix, &affixlen, &starflags);
2167 if (id < 0) /* Unknown lookup type */
2169 log_write(0, LOG_MAIN|LOG_PANIC, "%s in host list item \"%s\"",
2170 search_error_message, ss);
2173 isquery = mac_islookup(id, lookup_querystyle|lookup_absfilequery);
2178 switch(match_check_string(US"", ss, -1, TRUE, TRUE, TRUE, valueptr))
2181 case DEFER: return DEFER;
2182 default: return FAIL;
2186 /* Not a query-style lookup; must ensure the host name is present, and then we
2187 do a check on the name and all its aliases. */
2189 if (sender_host_name == NULL)
2191 HDEBUG(D_host_lookup)
2192 debug_printf("sender host name required, to match against %s\n", ss);
2193 if (host_lookup_failed || host_name_lookup() != OK)
2195 *error = string_sprintf("failed to find host name for %s",
2196 sender_host_address);;
2199 host_build_sender_fullhost();
2202 /* Match on the sender host name, using the general matching function */
2204 switch(match_check_string(sender_host_name, ss, -1, TRUE, TRUE, TRUE,
2208 case DEFER: return DEFER;
2211 /* If there are aliases, try matching on them. */
2213 aliases = sender_host_aliases;
2214 while (*aliases != NULL)
2216 switch(match_check_string(*aliases++, ss, -1, TRUE, TRUE, TRUE, valueptr))
2219 case DEFER: return DEFER;
2228 /*************************************************
2229 * Check a specific host matches a host list *
2230 *************************************************/
2232 /* This function is passed a host list containing items in a number of
2233 different formats and the identity of a host. Its job is to determine whether
2234 the given host is in the set of hosts defined by the list. The host name is
2235 passed as a pointer so that it can be looked up if needed and not already
2236 known. This is commonly the case when called from verify_check_host() to check
2237 an incoming connection. When called from elsewhere the host name should usually
2240 This function is now just a front end to match_check_list(), which runs common
2241 code for scanning a list. We pass it the check_host() function to perform a
2245 listptr pointer to the host list
2246 cache_bits pointer to cache for named lists, or NULL
2247 host_name the host name or NULL, implying use sender_host_name and
2248 sender_host_aliases, looking them up if required
2249 host_address the IP address
2250 valueptr if not NULL, data from a lookup is passed back here
2252 Returns: OK if the host is in the defined set
2253 FAIL if the host is not in the defined set,
2254 DEFER if a data lookup deferred (not a host lookup)
2256 If the host name was needed in order to make a comparison, and could not be
2257 determined from the IP address, the result is FAIL unless the item
2258 "+allow_unknown" was met earlier in the list, in which case OK is returned. */
2261 verify_check_this_host(uschar **listptr, unsigned int *cache_bits,
2262 uschar *host_name, uschar *host_address, uschar **valueptr)
2265 unsigned int *local_cache_bits = cache_bits;
2266 uschar *save_host_address = deliver_host_address;
2267 check_host_block cb;
2268 cb.host_name = host_name;
2269 cb.host_address = host_address;
2271 if (valueptr != NULL) *valueptr = NULL;
2273 /* If the host address starts off ::ffff: it is an IPv6 address in
2274 IPv4-compatible mode. Find the IPv4 part for checking against IPv4
2277 cb.host_ipv4 = (Ustrncmp(host_address, "::ffff:", 7) == 0)?
2278 host_address + 7 : host_address;
2280 /* During the running of the check, put the IP address into $host_address. In
2281 the case of calls from the smtp transport, it will already be there. However,
2282 in other calls (e.g. when testing ignore_target_hosts), it won't. Just to be on
2283 the safe side, any existing setting is preserved, though as I write this
2284 (November 2004) I can't see any cases where it is actually needed. */
2286 deliver_host_address = host_address;
2287 rc = match_check_list(
2288 listptr, /* the list */
2289 0, /* separator character */
2290 &hostlist_anchor, /* anchor pointer */
2291 &local_cache_bits, /* cache pointer */
2292 check_host, /* function for testing */
2293 &cb, /* argument for function */
2294 MCL_HOST, /* type of check */
2295 (host_address == sender_host_address)?
2296 US"host" : host_address, /* text for debugging */
2297 valueptr); /* where to pass back data */
2298 deliver_host_address = save_host_address;
2305 /*************************************************
2306 * Check the remote host matches a list *
2307 *************************************************/
2309 /* This is a front end to verify_check_this_host(), created because checking
2310 the remote host is a common occurrence. With luck, a good compiler will spot
2311 the tail recursion and optimize it. If there's no host address, this is
2312 command-line SMTP input - check against an empty string for the address.
2315 listptr pointer to the host list
2317 Returns: the yield of verify_check_this_host(),
2318 i.e. OK, FAIL, or DEFER
2322 verify_check_host(uschar **listptr)
2324 return verify_check_this_host(listptr, sender_host_cache, NULL,
2325 (sender_host_address == NULL)? US"" : sender_host_address, NULL);
2332 /*************************************************
2333 * Invert an IP address for a DNS black list *
2334 *************************************************/
2338 buffer where to put the answer
2339 address the address to invert
2343 invert_address(uschar *buffer, uschar *address)
2346 uschar *bptr = buffer;
2348 /* If this is an IPv4 address mapped into IPv6 format, adjust the pointer
2349 to the IPv4 part only. */
2351 if (Ustrncmp(address, "::ffff:", 7) == 0) address += 7;
2353 /* Handle IPv4 address: when HAVE_IPV6 is false, the result of host_aton() is
2356 if (host_aton(address, bin) == 1)
2360 for (i = 0; i < 4; i++)
2362 sprintf(CS bptr, "%d.", x & 255);
2363 while (*bptr) bptr++;
2368 /* Handle IPv6 address. Actually, as far as I know, there are no IPv6 addresses
2369 in any DNS black lists, and the format in which they will be looked up is
2370 unknown. This is just a guess. */
2376 for (j = 3; j >= 0; j--)
2379 for (i = 0; i < 8; i++)
2381 sprintf(CS bptr, "%x.", x & 15);
2382 while (*bptr) bptr++;
2392 /*************************************************
2393 * Perform a single dnsbl lookup *
2394 *************************************************/
2396 /* This function is called from verify_check_dnsbl() below.
2399 domain the outer dnsbl domain (for debug message)
2400 keydomain the current keydomain (for debug message)
2401 query the domain to be looked up
2402 iplist the list of matching IP addresses
2403 bitmask true if bitmask matching is wanted
2404 invert_result true if result to be inverted
2405 defer_return what to return for a defer
2407 Returns: OK if lookup succeeded
2412 one_check_dnsbl(uschar *domain, uschar *keydomain, uschar *query,
2413 uschar *iplist, BOOL bitmask, BOOL invert_result, int defer_return)
2418 dnsbl_cache_block *cb;
2419 int old_pool = store_pool;
2421 /* Look for this query in the cache. */
2423 t = tree_search(dnsbl_cache, query);
2425 /* If not cached from a previous lookup, we must do a DNS lookup, and
2426 cache the result in permanent memory. */
2430 store_pool = POOL_PERM;
2432 /* Set up a tree entry to cache the lookup */
2434 t = store_get(sizeof(tree_node) + Ustrlen(query));
2435 Ustrcpy(t->name, query);
2436 t->data.ptr = cb = store_get(sizeof(dnsbl_cache_block));
2437 (void)tree_insertnode(&dnsbl_cache, t);
2439 /* Do the DNS loopup . */
2441 HDEBUG(D_dnsbl) debug_printf("new DNS lookup for %s\n", query);
2442 cb->rc = dns_basic_lookup(&dnsa, query, T_A);
2443 cb->text_set = FALSE;
2447 /* If the lookup succeeded, cache the RHS address. The code allows for
2448 more than one address - this was for complete generality and the possible
2449 use of A6 records. However, A6 records have been reduced to experimental
2450 status (August 2001) and may die out. So they may never get used at all,
2451 let alone in dnsbl records. However, leave the code here, just in case.
2453 Quite apart from one A6 RR generating multiple addresses, there are DNS
2454 lists that return more than one A record, so we must handle multiple
2455 addresses generated in that way as well. */
2457 if (cb->rc == DNS_SUCCEED)
2460 dns_address **addrp = &(cb->rhs);
2461 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2463 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
2465 if (rr->type == T_A)
2467 dns_address *da = dns_address_from_rr(&dnsa, rr);
2471 while (da->next != NULL) da = da->next;
2472 addrp = &(da->next);
2477 /* If we didn't find any A records, change the return code. This can
2478 happen when there is a CNAME record but there are no A records for what
2481 if (cb->rhs == NULL) cb->rc = DNS_NODATA;
2484 store_pool = old_pool;
2487 /* Previous lookup was cached */
2491 HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
2495 /* We now have the result of the DNS lookup, either newly done, or cached
2496 from a previous call. If the lookup succeeded, check against the address
2497 list if there is one. This may be a positive equality list (introduced by
2498 "="), a negative equality list (introduced by "!="), a positive bitmask
2499 list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/
2501 if (cb->rc == DNS_SUCCEED)
2503 dns_address *da = NULL;
2504 uschar *addlist = cb->rhs->address;
2506 /* For A and AAAA records, there may be multiple addresses from multiple
2507 records. For A6 records (currently not expected to be used) there may be
2508 multiple addresses from a single record. */
2510 for (da = cb->rhs->next; da != NULL; da = da->next)
2511 addlist = string_sprintf("%s, %s", addlist, da->address);
2513 HDEBUG(D_dnsbl) debug_printf("DNS lookup for %s succeeded (yielding %s)\n",
2516 /* Address list check; this can be either for equality, or via a bitmask.
2517 In the latter case, all the bits must match. */
2523 uschar *ptr = iplist;
2525 while (string_nextinlist(&ptr, &ipsep, ip, sizeof(ip)) != NULL)
2527 /* Handle exact matching */
2530 for (da = cb->rhs; da != NULL; da = da->next)
2532 if (Ustrcmp(CS da->address, ip) == 0) break;
2535 /* Handle bitmask matching */
2541 /* At present, all known DNS blocking lists use A records, with
2542 IPv4 addresses on the RHS encoding the information they return. I
2543 wonder if this will linger on as the last vestige of IPv4 when IPv6
2544 is ubiquitous? Anyway, for now we use paranoia code to completely
2545 ignore IPv6 addresses. The default mask is 0, which always matches.
2546 We change this only for IPv4 addresses in the list. */
2548 if (host_aton(ip, address) == 1) mask = address[0];
2550 /* Scan the returned addresses, skipping any that are IPv6 */
2552 for (da = cb->rhs; da != NULL; da = da->next)
2554 if (host_aton(da->address, address) != 1) continue;
2555 if ((address[0] & mask) == mask) break;
2559 /* Break out if a match has been found */
2561 if (da != NULL) break;
2566 (a) No IP address in a positive list matched, or
2567 (b) An IP address in a negative list did match
2569 then behave as if the DNSBL lookup had not succeeded, i.e. the host is
2572 if (invert_result != (da == NULL))
2576 debug_printf("=> but we are not accepting this block class because\n");
2577 debug_printf("=> there was %s match for %c%s\n",
2578 invert_result? "an exclude":"no", bitmask? '&' : '=', iplist);
2584 /* Either there was no IP list, or the record matched. Look up a TXT record
2585 if it hasn't previously been done. */
2589 cb->text_set = TRUE;
2590 if (dns_basic_lookup(&dnsa, query, T_TXT) == DNS_SUCCEED)
2593 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2595 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
2596 if (rr->type == T_TXT) break;
2599 int len = (rr->data)[0];
2600 if (len > 511) len = 127;
2601 store_pool = POOL_PERM;
2602 cb->text = string_sprintf("%.*s", len, (const uschar *)(rr->data+1));
2603 store_pool = old_pool;
2608 dnslist_value = addlist;
2609 dnslist_text = cb->text;
2613 /* There was a problem with the DNS lookup */
2615 if (cb->rc != DNS_NOMATCH && cb->rc != DNS_NODATA)
2617 log_write(L_dnslist_defer, LOG_MAIN,
2618 "DNS list lookup defer (probably timeout) for %s: %s", query,
2619 (defer_return == OK)? US"assumed in list" :
2620 (defer_return == FAIL)? US"assumed not in list" :
2621 US"returned DEFER");
2622 return defer_return;
2625 /* No entry was found in the DNS; continue for next domain */
2629 debug_printf("DNS lookup for %s failed\n", query);
2630 debug_printf("=> that means %s is not listed at %s\n",
2640 /*************************************************
2641 * Check host against DNS black lists *
2642 *************************************************/
2644 /* This function runs checks against a list of DNS black lists, until one
2645 matches. Each item on the list can be of the form
2647 domain=ip-address/key
2649 The domain is the right-most domain that is used for the query, for example,
2650 blackholes.mail-abuse.org. If the IP address is present, there is a match only
2651 if the DNS lookup returns a matching IP address. Several addresses may be
2652 given, comma-separated, for example: x.y.z=127.0.0.1,127.0.0.2.
2654 If no key is given, what is looked up in the domain is the inverted IP address
2655 of the current client host. If a key is given, it is used to construct the
2656 domain for the lookup. For example,
2658 dsn.rfc-ignorant.org/$sender_address_domain
2660 After finding a match in the DNS, the domain is placed in $dnslist_domain, and
2661 then we check for a TXT record for an error message, and if found, save its
2662 value in $dnslist_text. We also cache everything in a tree, to optimize
2665 Note: an address for testing RBL is 192.203.178.39
2666 Note: an address for testing DUL is 192.203.178.4
2667 Note: a domain for testing RFCI is example.tld.dsn.rfc-ignorant.org
2670 listptr the domain/address/data list
2672 Returns: OK successful lookup (i.e. the address is on the list), or
2673 lookup deferred after +include_unknown
2674 FAIL name not found, or no data found for the given type, or
2675 lookup deferred after +exclude_unknown (default)
2676 DEFER lookup failure, if +defer_unknown was set
2680 verify_check_dnsbl(uschar **listptr)
2683 int defer_return = FAIL;
2684 BOOL invert_result = FALSE;
2685 uschar *list = *listptr;
2688 uschar buffer[1024];
2689 uschar query[256]; /* DNS domain max length */
2690 uschar revadd[128]; /* Long enough for IPv6 address */
2692 /* Indicate that the inverted IP address is not yet set up */
2696 /* In case this is the first time the DNS resolver is being used. */
2698 dns_init(FALSE, FALSE);
2700 /* Loop through all the domains supplied, until something matches */
2702 while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
2706 BOOL bitmask = FALSE;
2710 HDEBUG(D_dnsbl) debug_printf("DNS list check: %s\n", domain);
2712 /* Deal with special values that change the behaviour on defer */
2714 if (domain[0] == '+')
2716 if (strcmpic(domain, US"+include_unknown") == 0) defer_return = OK;
2717 else if (strcmpic(domain, US"+exclude_unknown") == 0) defer_return = FAIL;
2718 else if (strcmpic(domain, US"+defer_unknown") == 0) defer_return = DEFER;
2720 log_write(0, LOG_MAIN|LOG_PANIC, "unknown item in dnslist (ignored): %s",
2725 /* See if there's explicit data to be looked up */
2727 key = Ustrchr(domain, '/');
2728 if (key != NULL) *key++ = 0;
2730 /* See if there's a list of addresses supplied after the domain name. This is
2731 introduced by an = or a & character; if preceded by ! we invert the result.
2734 iplist = Ustrchr(domain, '=');
2738 iplist = Ustrchr(domain, '&');
2743 if (iplist > domain && iplist[-1] == '!')
2745 invert_result = TRUE;
2751 /* Check that what we have left is a sensible domain name. There is no reason
2752 why these domains should in fact use the same syntax as hosts and email
2753 domains, but in practice they seem to. However, there is little point in
2754 actually causing an error here, because that would no doubt hold up incoming
2755 mail. Instead, I'll just log it. */
2757 for (s = domain; *s != 0; s++)
2759 if (!isalnum(*s) && *s != '-' && *s != '.')
2761 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
2762 "strange characters - is this right?", domain);
2767 /* If there is no key string, construct the query by adding the domain name
2768 onto the inverted host address, and perform a single DNS lookup. */
2772 if (sender_host_address == NULL) return FAIL; /* can never match */
2773 if (revadd[0] == 0) invert_address(revadd, sender_host_address);
2774 frc = string_format(query, sizeof(query), "%s%s", revadd, domain);
2778 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
2779 "(ignored): %s...", query);
2783 rc = one_check_dnsbl(domain, sender_host_address, query, iplist, bitmask,
2784 invert_result, defer_return);
2788 dnslist_domain = string_copy(domain);
2789 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
2790 sender_host_address, domain);
2793 if (rc != FAIL) return rc; /* OK or DEFER */
2796 /* If there is a key string, it can be a list of domains or IP addresses to
2797 be concatenated with the main domain. */
2804 uschar keybuffer[256];
2806 while ((keydomain = string_nextinlist(&key, &keysep, keybuffer,
2807 sizeof(keybuffer))) != NULL)
2809 if (string_is_ip_address(keydomain, NULL) != 0)
2811 uschar keyrevadd[128];
2812 invert_address(keyrevadd, keydomain);
2813 frc = string_format(query, sizeof(query), "%s%s", keyrevadd, domain);
2817 frc = string_format(query, sizeof(query), "%s.%s", keydomain, domain);
2822 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
2823 "(ignored): %s...", query);
2827 rc = one_check_dnsbl(domain, keydomain, query, iplist, bitmask,
2828 invert_result, defer_return);
2832 dnslist_domain = string_copy(domain);
2833 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
2838 /* If the lookup deferred, remember this fact. We keep trying the rest
2839 of the list to see if we get a useful result, and if we don't, we return
2840 DEFER at the end. */
2842 if (rc == DEFER) defer = TRUE;
2843 } /* continue with next keystring domain/address */
2845 if (defer) return DEFER;
2847 } /* continue with next dnsdb outer domain */
2852 /* End of verify.c */