1 /* $Cambridge: exim/src/src/verify.c,v 1.26 2005/09/06 13:17:36 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. This has to
414 be delayed till now, because they may expand differently for different
415 hosts. If there's a failure, log it, but carry on with the defaults. */
417 deliver_host = host->name;
418 deliver_host_address = host->address;
419 deliver_domain = addr->domain;
420 if (!smtp_get_interface(tf->interface, host_af, addr, NULL, &interface,
422 !smtp_get_port(tf->port, addr, &port, US"callout"))
423 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
425 deliver_host = deliver_host_address = NULL;
426 deliver_domain = save_deliver_domain;
428 /* Set HELO string according to the protocol */
430 if (Ustrcmp(tf->protocol, "lmtp") == 0) helo = US"LHLO";
432 HDEBUG(D_verify) debug_printf("interface=%s port=%d\n", interface, port);
434 /* Set up the buffer for reading SMTP response packets. */
436 inblock.buffer = inbuffer;
437 inblock.buffersize = sizeof(inbuffer);
438 inblock.ptr = inbuffer;
439 inblock.ptrend = inbuffer;
441 /* Set up the buffer for holding SMTP commands while pipelining */
443 outblock.buffer = outbuffer;
444 outblock.buffersize = sizeof(outbuffer);
445 outblock.ptr = outbuffer;
446 outblock.cmd_count = 0;
447 outblock.authenticating = FALSE;
449 /* Connect to the host; on failure, just loop for the next one, but we
450 set the error for the last one. Use the callout_connect timeout. */
452 inblock.sock = outblock.sock =
453 smtp_connect(host, host_af, port, interface, callout_connect, TRUE);
454 if (inblock.sock < 0)
456 addr->message = string_sprintf("could not connect to %s [%s]: %s",
457 host->name, host->address, strerror(errno));
461 /* Wait for initial response, and then run the initial SMTP commands. The
462 smtp_write_command() function leaves its command in big_buffer. This is
463 used in error responses. Initialize it in case the connection is
466 Ustrcpy(big_buffer, "initial connection");
469 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
472 smtp_write_command(&outblock, FALSE, "%s %s\r\n", helo,
473 smtp_active_hostname) >= 0 &&
474 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
477 smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>\r\n",
478 from_address) >= 0 &&
479 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
482 /* If the host gave an initial error, or does not accept HELO or MAIL
483 FROM:<>, arrange to cache this information, but don't record anything for an
484 I/O error or a defer. Do not cache rejections when a non-empty sender has
485 been used, because that blocks the whole domain for all senders. */
489 *failure_ptr = US"mail";
490 if (errno == 0 && responsebuffer[0] == '5')
492 setflag(addr, af_verify_nsfail);
493 if (from_address[0] == 0) new_domain_record.result = ccache_reject;
497 /* Otherwise, proceed to check a "random" address (if required), then the
498 given address, and the postmaster address (if required). Between each check,
499 issue RSET, because some servers accept only one recipient after MAIL
504 new_domain_record.result = ccache_accept;
506 /* Do the random local part check first */
508 if (random_local_part != NULL)
510 uschar randombuffer[1024];
512 smtp_write_command(&outblock, FALSE,
513 "RCPT TO:<%.1000s@%.1000s>\r\n", random_local_part,
514 addr->domain) >= 0 &&
515 smtp_read_response(&inblock, randombuffer,
516 sizeof(randombuffer), '2', callout);
518 /* Remember when we last did a random test */
520 new_domain_record.random_stamp = time(NULL);
522 /* If accepted, we aren't going to do any further tests below. */
526 new_domain_record.random_result = ccache_accept;
529 /* Otherwise, cache a real negative response, and get back to the right
530 state to send RCPT. Unless there's some problem such as a dropped
531 connection, we expect to succeed, because the commands succeeded above. */
535 if (randombuffer[0] == '5')
536 new_domain_record.random_result = ccache_reject;
539 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
540 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
543 smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>\r\n",
544 from_address) >= 0 &&
545 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
548 else done = FALSE; /* Some timeout/connection problem */
551 /* If the host is accepting all local parts, as determined by the "random"
552 check, we don't need to waste time doing any further checking. */
554 if (new_domain_record.random_result != ccache_accept && done)
556 /* Get the rcpt_include_affixes flag from the transport if there is one,
557 but assume FALSE if there is not. */
560 smtp_write_command(&outblock, FALSE, "RCPT TO:<%.1000s>\r\n",
561 transport_rcpt_address(addr,
562 (addr->transport == NULL)? FALSE :
563 addr->transport->rcpt_include_affixes)) >= 0 &&
564 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
568 new_address_record.result = ccache_accept;
569 else if (errno == 0 && responsebuffer[0] == '5')
571 *failure_ptr = US"recipient";
572 new_address_record.result = ccache_reject;
575 /* Do postmaster check if requested; if a full check is required, we
576 check for RCPT TO:<postmaster> (no domain) in accordance with RFC 821. */
578 if (done && pm_mailfrom != NULL)
581 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
582 smtp_read_response(&inblock, responsebuffer,
583 sizeof(responsebuffer), '2', callout) &&
585 smtp_write_command(&outblock, FALSE,
586 "MAIL FROM:<%s>\r\n", pm_mailfrom) >= 0 &&
587 smtp_read_response(&inblock, responsebuffer,
588 sizeof(responsebuffer), '2', callout) &&
590 /* First try using the current domain */
593 smtp_write_command(&outblock, FALSE,
594 "RCPT TO:<postmaster@%.1000s>\r\n", addr->domain) >= 0 &&
595 smtp_read_response(&inblock, responsebuffer,
596 sizeof(responsebuffer), '2', callout)
601 /* If that doesn't work, and a full check is requested,
602 try without the domain. */
605 (options & vopt_callout_fullpm) != 0 &&
606 smtp_write_command(&outblock, FALSE,
607 "RCPT TO:<postmaster>\r\n") >= 0 &&
608 smtp_read_response(&inblock, responsebuffer,
609 sizeof(responsebuffer), '2', callout)
612 /* Sort out the cache record */
614 new_domain_record.postmaster_stamp = time(NULL);
617 new_domain_record.postmaster_result = ccache_accept;
618 else if (errno == 0 && responsebuffer[0] == '5')
620 *failure_ptr = US"postmaster";
621 setflag(addr, af_verify_pmfail);
622 new_domain_record.postmaster_result = ccache_reject;
625 } /* Random not accepted */
626 } /* MAIL FROM: accepted */
628 /* For any failure of the main check, other than a negative response, we just
629 close the connection and carry on. We can identify a negative response by the
630 fact that errno is zero. For I/O errors it will be non-zero
632 Set up different error texts for logging and for sending back to the caller
633 as an SMTP response. Log in all cases, using a one-line format. For sender
634 callouts, give a full response to the caller, but for recipient callouts,
635 don't give the IP address because this may be an internal host whose identity
636 is not to be widely broadcast. */
640 if (errno == ETIMEDOUT)
642 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
647 if (*responsebuffer == 0) Ustrcpy(responsebuffer, US"connection dropped");
650 string_sprintf("response to \"%s\" from %s [%s] was: %s",
651 big_buffer, host->name, host->address,
652 string_printing(responsebuffer));
654 addr->user_message = is_recipient?
655 string_sprintf("Callout verification failed:\n%s", responsebuffer)
657 string_sprintf("Called: %s\nSent: %s\nResponse: %s",
658 host->address, big_buffer, responsebuffer);
660 /* Hard rejection ends the process */
662 if (responsebuffer[0] == '5') /* Address rejected */
670 /* End the SMTP conversation and close the connection. */
672 if (send_quit) (void)smtp_write_command(&outblock, FALSE, "QUIT\r\n");
673 (void)close(inblock.sock);
674 } /* Loop through all hosts, while !done */
676 /* If we get here with done == TRUE, a successful callout happened, and yield
677 will be set OK or FAIL according to the response to the RCPT command.
678 Otherwise, we looped through the hosts but couldn't complete the business.
679 However, there may be domain-specific information to cache in both cases.
681 The value of the result field in the new_domain record is ccache_unknown if
682 there was an error before or with MAIL FROM:, and errno was not zero,
683 implying some kind of I/O error. We don't want to write the cache in that case.
684 Otherwise the value is ccache_accept or ccache_reject. */
686 if (!callout_no_cache && new_domain_record.result != ccache_unknown)
688 if ((dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE))
691 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
695 (void)dbfn_write(dbm_file, addr->domain, &new_domain_record,
696 (int)sizeof(dbdata_callout_cache));
697 HDEBUG(D_verify) debug_printf("wrote callout cache domain record:\n"
698 " result=%d postmaster=%d random=%d\n",
699 new_domain_record.result,
700 new_domain_record.postmaster_result,
701 new_domain_record.random_result);
705 /* If a definite result was obtained for the callout, cache it unless caching
710 if (!callout_no_cache && new_address_record.result != ccache_unknown)
712 if (dbm_file == NULL)
713 dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE);
714 if (dbm_file == NULL)
716 HDEBUG(D_verify) debug_printf("no callout cache available\n");
720 (void)dbfn_write(dbm_file, address_key, &new_address_record,
721 (int)sizeof(dbdata_callout_cache_address));
722 HDEBUG(D_verify) debug_printf("wrote %s callout cache address record\n",
723 (new_address_record.result == ccache_accept)? "positive" : "negative");
728 /* Failure to connect to any host, or any response other than 2xx or 5xx is a
729 temporary error. If there was only one host, and a response was received, leave
730 it alone if supplying details. Otherwise, give a generic response. */
734 uschar *dullmsg = string_sprintf("Could not complete %s verify callout",
735 is_recipient? "recipient" : "sender");
738 if (host_list->next != NULL || addr->message == NULL) addr->message = dullmsg;
740 addr->user_message = (!smtp_return_error_details)? dullmsg :
741 string_sprintf("%s for <%s>.\n"
742 "The mail server(s) for the domain may be temporarily unreachable, or\n"
743 "they may be permanently unreachable from this server. In the latter case,\n%s",
744 dullmsg, addr->address,
746 "the address will never be accepted."
748 "you need to change the address or create an MX record for its domain\n"
749 "if it is supposed to be generally accessible from the Internet.\n"
750 "Talk to your mail administrator for details.");
752 /* Force a specific error code */
754 addr->basic_errno = ERRNO_CALLOUTDEFER;
757 /* Come here from within the cache-reading code on fast-track exit. */
760 if (dbm_file != NULL) dbfn_close(dbm_file);
766 /*************************************************
767 * Copy error to toplevel address *
768 *************************************************/
770 /* This function is used when a verify fails or defers, to ensure that the
771 failure or defer information is in the original toplevel address. This applies
772 when an address is redirected to a single new address, and the failure or
773 deferral happens to the child address.
776 vaddr the verify address item
777 addr the final address item
780 Returns: the value of YIELD
784 copy_error(address_item *vaddr, address_item *addr, int yield)
788 vaddr->message = addr->message;
789 vaddr->user_message = addr->user_message;
790 vaddr->basic_errno = addr->basic_errno;
791 vaddr->more_errno = addr->more_errno;
799 /*************************************************
800 * Verify an email address *
801 *************************************************/
803 /* This function is used both for verification (-bv and at other times) and
804 address testing (-bt), which is indicated by address_test_mode being set.
807 vaddr contains the address to verify; the next field in this block
809 f if not NULL, write the result to this file
810 options various option bits:
811 vopt_fake_sender => this sender verify is not for the real
812 sender (it was verify=sender=xxxx or an address from a
813 header line) - rewriting must not change sender_address
814 vopt_is_recipient => this is a recipient address, otherwise
815 it's a sender address - this affects qualification and
816 rewriting and messages from callouts
817 vopt_qualify => qualify an unqualified address; else error
818 vopt_expn => called from SMTP EXPN command
819 vopt_success_on_redirect => when a new address is generated
820 the verification instantly succeeds
822 These ones are used by do_callout() -- the options variable
825 vopt_callout_fullpm => if postmaster check, do full one
826 vopt_callout_no_cache => don't use callout cache
827 vopt_callout_random => do the "random" thing
828 vopt_callout_recipsender => use real sender for recipient
829 vopt_callout_recippmaster => use postmaster for recipient
831 callout if > 0, specifies that callout is required, and gives timeout
832 for individual commands
833 callout_overall if > 0, gives overall timeout for the callout function;
834 if < 0, a default is used (see do_callout())
835 callout_connect the connection timeout for callouts
836 se_mailfrom when callout is requested to verify a sender, use this
837 in MAIL FROM; NULL => ""
838 pm_mailfrom when callout is requested, if non-NULL, do the postmaster
839 thing and use this as the sender address (may be "")
841 routed if not NULL, set TRUE if routing succeeded, so we can
842 distinguish between routing failed and callout failed
844 Returns: OK address verified
845 FAIL address failed to verify
846 DEFER can't tell at present
850 verify_address(address_item *vaddr, FILE *f, int options, int callout,
851 int callout_overall, int callout_connect, uschar *se_mailfrom,
852 uschar *pm_mailfrom, BOOL *routed)
855 BOOL full_info = (f == NULL)? FALSE : (debug_selector != 0);
856 BOOL is_recipient = (options & vopt_is_recipient) != 0;
857 BOOL expn = (options & vopt_expn) != 0;
858 BOOL success_on_redirect = (options & vopt_success_on_redirect) != 0;
861 int verify_type = expn? v_expn :
862 address_test_mode? v_none :
863 is_recipient? v_recipient : v_sender;
864 address_item *addr_list;
865 address_item *addr_new = NULL;
866 address_item *addr_remote = NULL;
867 address_item *addr_local = NULL;
868 address_item *addr_succeed = NULL;
869 uschar **failure_ptr = is_recipient?
870 &recipient_verify_failure : &sender_verify_failure;
871 uschar *ko_prefix, *cr;
872 uschar *address = vaddr->address;
874 uschar null_sender[] = { 0 }; /* Ensure writeable memory */
876 /* Clear, just in case */
880 /* Set up a prefix and suffix for error message which allow us to use the same
881 output statements both in EXPN mode (where an SMTP response is needed) and when
882 debugging with an output file. */
886 ko_prefix = US"553 ";
889 else ko_prefix = cr = US"";
891 /* Add qualify domain if permitted; otherwise an unqualified address fails. */
893 if (parse_find_at(address) == NULL)
895 if ((options & vopt_qualify) == 0)
898 fprintf(f, "%sA domain is required for \"%s\"%s\n", ko_prefix, address,
900 *failure_ptr = US"qualify";
903 address = rewrite_address_qualify(address, is_recipient);
908 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
909 debug_printf("%s %s\n", address_test_mode? "Testing" : "Verifying", address);
912 /* Rewrite and report on it. Clear the domain and local part caches - these
913 may have been set by domains and local part tests during an ACL. */
915 if (global_rewrite_rules != NULL)
917 uschar *old = address;
918 address = rewrite_address(address, is_recipient, FALSE,
919 global_rewrite_rules, rewrite_existflags);
922 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->localpart_cache[i] = 0;
923 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->domain_cache[i] = 0;
924 if (f != NULL && !expn) fprintf(f, "Address rewritten as: %s\n", address);
928 /* If this is the real sender address, we must update sender_address at
929 this point, because it may be referred to in the routers. */
931 if ((options & (vopt_fake_sender|vopt_is_recipient)) == 0)
932 sender_address = address;
934 /* If the address was rewritten to <> no verification can be done, and we have
935 to return OK. This rewriting is permitted only for sender addresses; for other
936 addresses, such rewriting fails. */
938 if (address[0] == 0) return OK;
940 /* Save a copy of the sender address for re-instating if we change it to <>
941 while verifying a sender address (a nice bit of self-reference there). */
943 save_sender = sender_address;
945 /* Update the address structure with the possibly qualified and rewritten
946 address. Set it up as the starting address on the chain of new addresses. */
948 vaddr->address = address;
951 /* We need a loop, because an address can generate new addresses. We must also
952 cope with generated pipes and files at the top level. (See also the code and
953 comment in deliver.c.) However, it is usually the case that the router for
954 user's .forward files has its verify flag turned off.
956 If an address generates more than one child, the loop is used only when
957 full_info is set, and this can only be set locally. Remote enquiries just get
958 information about the top level address, not anything that it generated. */
960 while (addr_new != NULL)
963 address_item *addr = addr_new;
965 addr_new = addr->next;
970 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
971 debug_printf("Considering %s\n", addr->address);
974 /* Handle generated pipe, file or reply addresses. We don't get these
975 when handling EXPN, as it does only one level of expansion. */
977 if (testflag(addr, af_pfr))
984 if (addr->address[0] == '>')
986 allow = testflag(addr, af_allow_reply);
987 fprintf(f, "%s -> mail %s", addr->parent->address, addr->address + 1);
991 allow = (addr->address[0] == '|')?
992 testflag(addr, af_allow_pipe) : testflag(addr, af_allow_file);
993 fprintf(f, "%s -> %s", addr->parent->address, addr->address);
996 if (addr->basic_errno == ERRNO_BADTRANSPORT)
997 fprintf(f, "\n*** Error in setting up pipe, file, or autoreply:\n"
998 "%s\n", addr->message);
1000 fprintf(f, "\n transport = %s\n", addr->transport->name);
1002 fprintf(f, " *** forbidden ***\n");
1007 /* Just in case some router parameter refers to it. */
1009 return_path = (addr->p.errors_address != NULL)?
1010 addr->p.errors_address : sender_address;
1012 /* Split the address into domain and local part, handling the %-hack if
1013 necessary, and then route it. While routing a sender address, set
1014 $sender_address to <> because that is what it will be if we were trying to
1015 send a bounce to the sender. */
1017 if (routed != NULL) *routed = FALSE;
1018 if ((rc = deliver_split_address(addr)) == OK)
1020 if (!is_recipient) sender_address = null_sender;
1021 rc = route_address(addr, &addr_local, &addr_remote, &addr_new,
1022 &addr_succeed, verify_type);
1023 sender_address = save_sender; /* Put back the real sender */
1026 /* If routing an address succeeded, set the flag that remembers, for use when
1027 an ACL cached a sender verify (in case a callout fails). Then if routing set
1028 up a list of hosts or the transport has a host list, and the callout option
1029 is set, and we aren't in a host checking run, do the callout verification,
1030 and set another flag that notes that a callout happened. */
1034 if (routed != NULL) *routed = TRUE;
1037 host_item *host_list = addr->host_list;
1039 /* Default, if no remote transport, to NULL for the interface (=> any),
1040 "smtp" for the port, and "smtp" for the protocol. */
1042 transport_feedback tf = { NULL, US"smtp", US"smtp", NULL, FALSE, FALSE };
1044 /* If verification yielded a remote transport, we want to use that
1045 transport's options, so as to mimic what would happen if we were really
1046 sending a message to this address. */
1048 if (addr->transport != NULL && !addr->transport->info->local)
1050 (void)(addr->transport->setup)(addr->transport, addr, &tf, NULL);
1052 /* If the transport has hosts and the router does not, or if the
1053 transport is configured to override the router's hosts, we must build a
1054 host list of the transport's hosts, and find the IP addresses */
1056 if (tf.hosts != NULL && (host_list == NULL || tf.hosts_override))
1059 uschar *save_deliver_domain = deliver_domain;
1060 uschar *save_deliver_localpart = deliver_localpart;
1062 host_list = NULL; /* Ignore the router's hosts */
1064 deliver_domain = addr->domain;
1065 deliver_localpart = addr->local_part;
1066 s = expand_string(tf.hosts);
1067 deliver_domain = save_deliver_domain;
1068 deliver_localpart = save_deliver_localpart;
1072 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand list of hosts "
1073 "\"%s\" in %s transport for callout: %s", tf.hosts,
1074 addr->transport->name, expand_string_message);
1078 uschar *canonical_name;
1079 host_item *host, *nexthost;
1080 host_build_hostlist(&host_list, s, tf.hosts_randomize);
1082 /* Just ignore failures to find a host address. If we don't manage
1083 to find any addresses, the callout will defer. Note that more than
1084 one address may be found for a single host, which will result in
1085 additional host items being inserted into the chain. Hence we must
1086 save the next host first. */
1088 for (host = host_list; host != NULL; host = nexthost)
1090 nexthost = host->next;
1091 if (tf.gethostbyname ||
1092 string_is_ip_address(host->name, NULL) > 0)
1093 (void)host_find_byname(host, NULL, &canonical_name, TRUE);
1096 int flags = HOST_FIND_BY_A;
1097 if (tf.qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
1098 if (tf.search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
1099 (void)host_find_bydns(host, NULL, flags, NULL, NULL, NULL,
1100 &canonical_name, NULL);
1107 /* Can only do a callout if we have at least one host! If the callout
1108 fails, it will have set ${sender,recipient}_verify_failure. */
1110 if (host_list != NULL)
1112 HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n");
1113 if (host_checking && !host_checking_callout)
1116 debug_printf("... callout omitted by default when host testing\n"
1117 "(Use -bhc if you want the callouts to happen.)\n");
1121 rc = do_callout(addr, host_list, &tf, callout, callout_overall,
1122 callout_connect, options, se_mailfrom, pm_mailfrom);
1127 HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor "
1128 "transport provided a host list\n");
1133 /* Otherwise, any failure is a routing failure */
1135 else *failure_ptr = US"route";
1137 /* A router may return REROUTED if it has set up a child address as a result
1138 of a change of domain name (typically from widening). In this case we always
1139 want to continue to verify the new child. */
1141 if (rc == REROUTED) continue;
1143 /* Handle hard failures */
1150 fprintf(f, "%s%s %s", ko_prefix, address,
1151 address_test_mode? "is undeliverable" : "failed to verify");
1152 if (!expn && admin_user)
1154 if (addr->basic_errno > 0)
1155 fprintf(f, ": %s", strerror(addr->basic_errno));
1156 if (addr->message != NULL)
1157 fprintf(f, ":\n %s", addr->message);
1159 fprintf(f, "%s\n", cr);
1162 if (!full_info) return copy_error(vaddr, addr, FAIL);
1168 else if (rc == DEFER)
1173 fprintf(f, "%s%s cannot be resolved at this time", ko_prefix, address);
1174 if (!expn && admin_user)
1176 if (addr->basic_errno > 0)
1177 fprintf(f, ":\n %s", strerror(addr->basic_errno));
1178 if (addr->message != NULL)
1179 fprintf(f, ":\n %s", addr->message);
1180 else if (addr->basic_errno <= 0)
1181 fprintf(f, ":\n unknown error");
1184 fprintf(f, "%s\n", cr);
1186 if (!full_info) return copy_error(vaddr, addr, DEFER);
1187 else if (yield == OK) yield = DEFER;
1190 /* If we are handling EXPN, we do not want to continue to route beyond
1195 uschar *ok_prefix = US"250-";
1196 if (addr_new == NULL)
1198 if (addr_local == NULL && addr_remote == NULL)
1199 fprintf(f, "250 mail to <%s> is discarded\r\n", address);
1201 fprintf(f, "250 <%s>\r\n", address);
1203 else while (addr_new != NULL)
1205 address_item *addr2 = addr_new;
1206 addr_new = addr2->next;
1207 if (addr_new == NULL) ok_prefix = US"250 ";
1208 fprintf(f, "%s<%s>\r\n", ok_prefix, addr2->address);
1213 /* Successful routing other than EXPN. */
1217 /* Handle successful routing when short info wanted. Otherwise continue for
1218 other (generated) addresses. Short info is the operational case. Full info
1219 can be requested only when debug_selector != 0 and a file is supplied.
1221 There is a conflict between the use of aliasing as an alternate email
1222 address, and as a sort of mailing list. If an alias turns the incoming
1223 address into just one address (e.g. J.Caesar->jc44) you may well want to
1224 carry on verifying the generated address to ensure it is valid when
1225 checking incoming mail. If aliasing generates multiple addresses, you
1226 probably don't want to do this. Exim therefore treats the generation of
1227 just a single new address as a special case, and continues on to verify the
1228 generated address. */
1230 if (!full_info && /* Stop if short info wanted AND */
1231 (((addr_new == NULL || /* No new address OR */
1232 addr_new->next != NULL || /* More than one new address OR */
1233 testflag(addr_new, af_pfr))) /* New address is pfr */
1235 (addr_new != NULL && /* At least one new address AND */
1236 success_on_redirect))) /* success_on_redirect is set */
1238 if (f != NULL) fprintf(f, "%s %s\n", address,
1239 address_test_mode? "is deliverable" : "verified");
1241 /* If we have carried on to verify a child address, we want the value
1242 of $address_data to be that of the child */
1244 vaddr->p.address_data = addr->p.address_data;
1248 } /* Loop for generated addresses */
1250 /* Display the full results of the successful routing, including any generated
1251 addresses. Control gets here only when full_info is set, which requires f not
1252 to be NULL, and this occurs only when a top-level verify is called with the
1253 debugging switch on.
1255 If there are no local and no remote addresses, and there were no pipes, files,
1256 or autoreplies, and there were no errors or deferments, the message is to be
1257 discarded, usually because of the use of :blackhole: in an alias file. */
1259 if (allok && addr_local == NULL && addr_remote == NULL)
1260 fprintf(f, "mail to %s is discarded\n", address);
1262 else for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++)
1264 while (addr_list != NULL)
1266 address_item *addr = addr_list;
1267 address_item *p = addr->parent;
1268 addr_list = addr->next;
1270 fprintf(f, "%s", CS addr->address);
1271 #ifdef EXPERIMENTAL_SRS
1272 if(addr->p.srs_sender)
1273 fprintf(f, " [srs = %s]", addr->p.srs_sender);
1277 fprintf(f, "\n <-- %s", p->address);
1282 /* Show router, and transport */
1284 fprintf(f, "router = %s, ", addr->router->name);
1285 fprintf(f, "transport = %s\n", (addr->transport == NULL)? US"unset" :
1286 addr->transport->name);
1288 /* Show any hosts that are set up by a router unless the transport
1289 is going to override them; fiddle a bit to get a nice format. */
1291 if (addr->host_list != NULL && addr->transport != NULL &&
1292 !addr->transport->overrides_hosts)
1297 for (h = addr->host_list; h != NULL; h = h->next)
1299 int len = Ustrlen(h->name);
1300 if (len > maxlen) maxlen = len;
1301 len = (h->address != NULL)? Ustrlen(h->address) : 7;
1302 if (len > maxaddlen) maxaddlen = len;
1304 for (h = addr->host_list; h != NULL; h = h->next)
1306 int len = Ustrlen(h->name);
1307 fprintf(f, " host %s ", h->name);
1308 while (len++ < maxlen) fprintf(f, " ");
1309 if (h->address != NULL)
1311 fprintf(f, "[%s] ", h->address);
1312 len = Ustrlen(h->address);
1314 else if (!addr->transport->info->local) /* Omit [unknown] for local */
1316 fprintf(f, "[unknown] ");
1320 while (len++ < maxaddlen) fprintf(f," ");
1321 if (h->mx >= 0) fprintf(f, "MX=%d", h->mx);
1322 if (h->port != PORT_NONE) fprintf(f, " port=%d", h->port);
1323 if (h->status == hstatus_unusable) fprintf(f, " ** unusable **");
1330 /* Will be DEFER or FAIL if any one address has, only for full_info (which is
1331 the -bv or -bt case). */
1339 /*************************************************
1340 * Check headers for syntax errors *
1341 *************************************************/
1343 /* This function checks those header lines that contain addresses, and verifies
1344 that all the addresses therein are syntactially correct.
1347 msgptr where to put an error message
1354 verify_check_headers(uschar **msgptr)
1359 for (h = header_list; h != NULL; h = h->next)
1361 if (h->type != htype_from &&
1362 h->type != htype_reply_to &&
1363 h->type != htype_sender &&
1364 h->type != htype_to &&
1365 h->type != htype_cc &&
1366 h->type != htype_bcc)
1369 colon = Ustrchr(h->text, ':');
1371 while (isspace(*s)) s++;
1373 parse_allow_group = TRUE; /* Allow group syntax */
1375 /* Loop for multiple addresses in the header */
1379 uschar *ss = parse_find_address_end(s, FALSE);
1380 uschar *recipient, *errmess;
1381 int terminator = *ss;
1382 int start, end, domain;
1384 /* Temporarily terminate the string at this point, and extract the
1385 operative address within. */
1388 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
1391 /* Permit an unqualified address only if the message is local, or if the
1392 sending host is configured to be permitted to send them. */
1394 if (recipient != NULL && domain == 0)
1396 if (h->type == htype_from || h->type == htype_sender)
1398 if (!allow_unqualified_sender) recipient = NULL;
1402 if (!allow_unqualified_recipient) recipient = NULL;
1404 if (recipient == NULL) errmess = US"unqualified address not permitted";
1407 /* It's an error if no address could be extracted, except for the special
1408 case of an empty address. */
1410 if (recipient == NULL && Ustrcmp(errmess, "empty address") != 0)
1412 uschar *verb = US"is";
1416 /* Arrange not to include any white space at the end in the
1419 while (t > s && isspace(t[-1])) t--;
1421 /* Add the address which failed to the error message, since in a
1422 header with very many addresses it is sometimes hard to spot
1423 which one is at fault. However, limit the amount of address to
1424 quote - cases have been seen where, for example, a missing double
1425 quote in a humungous To: header creates an "address" that is longer
1426 than string_sprintf can handle. */
1435 *msgptr = string_printing(
1436 string_sprintf("%s: failing address in \"%.*s\" header %s: %.*s",
1437 errmess, colon - h->text, h->text, verb, len, s));
1442 /* Advance to the next address */
1444 s = ss + (terminator? 1:0);
1445 while (isspace(*s)) s++;
1446 } /* Next address */
1454 /*************************************************
1455 * Check for blind recipients *
1456 *************************************************/
1458 /* This function checks that every (envelope) recipient is mentioned in either
1459 the To: or Cc: header lines, thus detecting blind carbon copies.
1461 There are two ways of scanning that could be used: either scan the header lines
1462 and tick off the recipients, or scan the recipients and check the header lines.
1463 The original proposed patch did the former, but I have chosen to do the latter,
1464 because (a) it requires no memory and (b) will use fewer resources when there
1465 are many addresses in To: and/or Cc: and only one or two envelope recipients.
1468 Returns: OK if there are no blind recipients
1469 FAIL if there is at least one blind recipient
1473 verify_check_notblind(void)
1476 for (i = 0; i < recipients_count; i++)
1480 uschar *address = recipients_list[i].address;
1482 for (h = header_list; !found && h != NULL; h = h->next)
1486 if (h->type != htype_to && h->type != htype_cc) continue;
1488 colon = Ustrchr(h->text, ':');
1490 while (isspace(*s)) s++;
1492 parse_allow_group = TRUE; /* Allow group syntax */
1494 /* Loop for multiple addresses in the header */
1498 uschar *ss = parse_find_address_end(s, FALSE);
1499 uschar *recipient,*errmess;
1500 int terminator = *ss;
1501 int start, end, domain;
1503 /* Temporarily terminate the string at this point, and extract the
1504 operative address within. */
1507 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
1510 /* If we found a valid recipient that has a domain, compare it with the
1511 envelope recipient. Local parts are compared case-sensitively, domains
1512 case-insensitively. By comparing from the start with length "domain", we
1513 include the "@" at the end, which ensures that we are comparing the whole
1514 local part of each address. */
1516 if (recipient != NULL && domain != 0)
1518 found = Ustrncmp(recipient, address, domain) == 0 &&
1519 strcmpic(recipient + domain, address + domain) == 0;
1523 /* Advance to the next address */
1525 s = ss + (terminator? 1:0);
1526 while (isspace(*s)) s++;
1527 } /* Next address */
1528 } /* Next header (if found is false) */
1530 if (!found) return FAIL;
1531 } /* Next recipient */
1538 /*************************************************
1539 * Find if verified sender *
1540 *************************************************/
1542 /* Usually, just a single address is verified as the sender of the message.
1543 However, Exim can be made to verify other addresses as well (often related in
1544 some way), and this is useful in some environments. There may therefore be a
1545 chain of such addresses that have previously been tested. This function finds
1546 whether a given address is on the chain.
1548 Arguments: the address to be verified
1549 Returns: pointer to an address item, or NULL
1553 verify_checked_sender(uschar *sender)
1556 for (addr = sender_verified_list; addr != NULL; addr = addr->next)
1557 if (Ustrcmp(sender, addr->address) == 0) break;
1565 /*************************************************
1566 * Get valid header address *
1567 *************************************************/
1569 /* Scan the originator headers of the message, looking for an address that
1570 verifies successfully. RFC 822 says:
1572 o The "Sender" field mailbox should be sent notices of
1573 any problems in transport or delivery of the original
1574 messages. If there is no "Sender" field, then the
1575 "From" field mailbox should be used.
1577 o If the "Reply-To" field exists, then the reply should
1578 go to the addresses indicated in that field and not to
1579 the address(es) indicated in the "From" field.
1581 So we check a Sender field if there is one, else a Reply_to field, else a From
1582 field. As some strange messages may have more than one of these fields,
1583 especially if they are resent- fields, check all of them if there is more than
1587 user_msgptr points to where to put a user error message
1588 log_msgptr points to where to put a log error message
1589 callout timeout for callout check (passed to verify_address())
1590 callout_overall overall callout timeout (ditto)
1591 callout_connect connect callout timeout (ditto)
1592 se_mailfrom mailfrom for verify; NULL => ""
1593 pm_mailfrom sender for pm callout check (passed to verify_address())
1594 options callout options (passed to verify_address())
1595 verrno where to put the address basic_errno
1597 If log_msgptr is set to something without setting user_msgptr, the caller
1598 normally uses log_msgptr for both things.
1600 Returns: result of the verification attempt: OK, FAIL, or DEFER;
1601 FAIL is given if no appropriate headers are found
1605 verify_check_header_address(uschar **user_msgptr, uschar **log_msgptr,
1606 int callout, int callout_overall, int callout_connect, uschar *se_mailfrom,
1607 uschar *pm_mailfrom, int options, int *verrno)
1609 static int header_types[] = { htype_sender, htype_reply_to, htype_from };
1613 for (i = 0; i < 3; i++)
1616 for (h = header_list; h != NULL; h = h->next)
1618 int terminator, new_ok;
1619 uschar *s, *ss, *endname;
1621 if (h->type != header_types[i]) continue;
1622 s = endname = Ustrchr(h->text, ':') + 1;
1626 address_item *vaddr;
1628 while (isspace(*s) || *s == ',') s++;
1629 if (*s == 0) break; /* End of header */
1631 ss = parse_find_address_end(s, FALSE);
1633 /* The terminator is a comma or end of header, but there may be white
1634 space preceding it (including newline for the last address). Move back
1635 past any white space so we can check against any cached envelope sender
1636 address verifications. */
1638 while (isspace(ss[-1])) ss--;
1642 HDEBUG(D_verify) debug_printf("verifying %.*s header address %s\n",
1643 (int)(endname - h->text), h->text, s);
1645 /* See if we have already verified this address as an envelope sender,
1646 and if so, use the previous answer. */
1648 vaddr = verify_checked_sender(s);
1650 if (vaddr != NULL && /* Previously checked */
1651 (callout <= 0 || /* No callout needed; OR */
1652 vaddr->special_action > 256)) /* Callout was done */
1654 new_ok = vaddr->special_action & 255;
1655 HDEBUG(D_verify) debug_printf("previously checked as envelope sender\n");
1656 *ss = terminator; /* Restore shortened string */
1659 /* Otherwise we run the verification now. We must restore the shortened
1660 string before running the verification, so the headers are correct, in
1661 case there is any rewriting. */
1665 int start, end, domain;
1666 uschar *address = parse_extract_address(s, log_msgptr, &start,
1667 &end, &domain, FALSE);
1671 /* If verification failed because of a syntax error, fail this
1672 function, and ensure that the failing address gets added to the error
1675 if (address == NULL)
1678 if (*log_msgptr != NULL)
1680 while (ss > s && isspace(ss[-1])) ss--;
1681 *log_msgptr = string_sprintf("syntax error in '%.*s' header when "
1682 "scanning for sender: %s in \"%.*s\"",
1683 endname - h->text, h->text, *log_msgptr, ss - s, s);
1688 /* Else go ahead with the sender verification. But it isn't *the*
1689 sender of the message, so set vopt_fake_sender to stop sender_address
1690 being replaced after rewriting or qualification. */
1694 vaddr = deliver_make_addr(address, FALSE);
1695 new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender,
1696 callout, callout_overall, callout_connect, se_mailfrom,
1701 /* We now have the result, either newly found, or cached. If we are
1702 giving out error details, set a specific user error. This means that the
1703 last of these will be returned to the user if all three fail. We do not
1704 set a log message - the generic one below will be used. */
1708 *verrno = vaddr->basic_errno;
1709 if (smtp_return_error_details)
1711 *user_msgptr = string_sprintf("Rejected after DATA: "
1712 "could not verify \"%.*s\" header address\n%s: %s",
1713 endname - h->text, h->text, vaddr->address, vaddr->message);
1717 /* Success or defer */
1719 if (new_ok == OK) return OK;
1720 if (new_ok == DEFER) yield = DEFER;
1722 /* Move on to any more addresses in the header */
1729 if (yield == FAIL && *log_msgptr == NULL)
1730 *log_msgptr = US"there is no valid sender in any header line";
1732 if (yield == DEFER && *log_msgptr == NULL)
1733 *log_msgptr = US"all attempts to verify a sender in a header line deferred";
1741 /*************************************************
1742 * Get RFC 1413 identification *
1743 *************************************************/
1745 /* Attempt to get an id from the sending machine via the RFC 1413 protocol. If
1746 the timeout is set to zero, then the query is not done. There may also be lists
1747 of hosts and nets which are exempt. To guard against malefactors sending
1748 non-printing characters which could, for example, disrupt a message's headers,
1749 make sure the string consists of printing characters only.
1752 port the port to connect to; usually this is IDENT_PORT (113), but when
1753 running in the test harness with -bh a different value is used.
1757 Side effect: any received ident value is put in sender_ident (NULL otherwise)
1761 verify_get_ident(int port)
1763 int sock, host_af, qlen;
1764 int received_sender_port, received_interface_port, n;
1766 uschar buffer[2048];
1768 /* Default is no ident. Check whether we want to do an ident check for this
1771 sender_ident = NULL;
1772 if (rfc1413_query_timeout <= 0 || verify_check_host(&rfc1413_hosts) != OK)
1775 DEBUG(D_ident) debug_printf("doing ident callback\n");
1777 /* Set up a connection to the ident port of the remote host. Bind the local end
1778 to the incoming interface address. If the sender host address is an IPv6
1779 address, the incoming interface address will also be IPv6. */
1781 host_af = (Ustrchr(sender_host_address, ':') == NULL)? AF_INET : AF_INET6;
1782 sock = ip_socket(SOCK_STREAM, host_af);
1783 if (sock < 0) return;
1785 if (ip_bind(sock, host_af, interface_address, 0) < 0)
1787 DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n",
1792 if (ip_connect(sock, host_af, sender_host_address, port, rfc1413_query_timeout)
1795 if (errno == ETIMEDOUT && (log_extra_selector & LX_ident_timeout) != 0)
1797 log_write(0, LOG_MAIN, "ident connection to %s timed out",
1798 sender_host_address);
1802 DEBUG(D_ident) debug_printf("ident connection to %s failed: %s\n",
1803 sender_host_address, strerror(errno));
1808 /* Construct and send the query. */
1810 sprintf(CS buffer, "%d , %d\r\n", sender_host_port, interface_port);
1811 qlen = Ustrlen(buffer);
1812 if (send(sock, buffer, qlen, 0) < 0)
1814 DEBUG(D_ident) debug_printf("ident send failed: %s\n", strerror(errno));
1818 /* Read a response line. We put it into the rest of the buffer, using several
1819 recv() calls if necessary. */
1827 int size = sizeof(buffer) - (p - buffer);
1829 if (size <= 0) goto END_OFF; /* Buffer filled without seeing \n. */
1830 count = ip_recv(sock, p, size, rfc1413_query_timeout);
1831 if (count <= 0) goto END_OFF; /* Read error or EOF */
1833 /* Scan what we just read, to see if we have reached the terminating \r\n. Be
1834 generous, and accept a plain \n terminator as well. The only illegal
1837 for (pp = p; pp < p + count; pp++)
1839 if (*pp == 0) goto END_OFF; /* Zero octet not allowed */
1842 if (pp[-1] == '\r') pp--;
1844 goto GOT_DATA; /* Break out of both loops */
1848 /* Reached the end of the data without finding \n. Let the loop continue to
1849 read some more, if there is room. */
1856 /* We have received a line of data. Check it carefully. It must start with the
1857 same two port numbers that we sent, followed by data as defined by the RFC. For
1860 12345 , 25 : USERID : UNIX :root
1862 However, the amount of white space may be different to what we sent. In the
1863 "osname" field there may be several sub-fields, comma separated. The data we
1864 actually want to save follows the third colon. Some systems put leading spaces
1865 in it - we discard those. */
1867 if (sscanf(CS buffer + qlen, "%d , %d%n", &received_sender_port,
1868 &received_interface_port, &n) != 2 ||
1869 received_sender_port != sender_host_port ||
1870 received_interface_port != interface_port)
1873 p = buffer + qlen + n;
1874 while(isspace(*p)) p++;
1875 if (*p++ != ':') goto END_OFF;
1876 while(isspace(*p)) p++;
1877 if (Ustrncmp(p, "USERID", 6) != 0) goto END_OFF;
1879 while(isspace(*p)) p++;
1880 if (*p++ != ':') goto END_OFF;
1881 while (*p != 0 && *p != ':') p++;
1882 if (*p++ == 0) goto END_OFF;
1883 while(isspace(*p)) p++;
1884 if (*p == 0) goto END_OFF;
1886 /* The rest of the line is the data we want. We turn it into printing
1887 characters when we save it, so that it cannot mess up the format of any logging
1888 or Received: lines into which it gets inserted. We keep a maximum of 127
1891 sender_ident = string_printing(string_copyn(p, 127));
1892 DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident);
1902 /*************************************************
1903 * Match host to a single host-list item *
1904 *************************************************/
1906 /* This function compares a host (name or address) against a single item
1907 from a host list. The host name gets looked up if it is needed and is not
1908 already known. The function is called from verify_check_this_host() via
1909 match_check_list(), which is why most of its arguments are in a single block.
1912 arg the argument block (see below)
1913 ss the host-list item
1914 valueptr where to pass back looked up data, or NULL
1915 error for error message when returning ERROR
1918 host_name (a) the host name, or
1919 (b) NULL, implying use sender_host_name and
1920 sender_host_aliases, looking them up if required, or
1921 (c) the empty string, meaning that only IP address matches
1923 host_address the host address
1924 host_ipv4 the IPv4 address taken from an IPv6 one
1928 DEFER lookup deferred
1929 ERROR (a) failed to find the host name or IP address, or
1930 (b) unknown lookup type specified, or
1931 (c) host name encountered when only IP addresses are
1936 check_host(void *arg, uschar *ss, uschar **valueptr, uschar **error)
1938 check_host_block *cb = (check_host_block *)arg;
1941 BOOL iplookup = FALSE;
1942 BOOL isquery = FALSE;
1943 BOOL isiponly = cb->host_name != NULL && cb->host_name[0] == 0;
1948 /* Optimize for the special case when the pattern is "*". */
1950 if (*ss == '*' && ss[1] == 0) return OK;
1952 /* If the pattern is empty, it matches only in the case when there is no host -
1953 this can occur in ACL checking for SMTP input using the -bs option. In this
1954 situation, the host address is the empty string. */
1956 if (cb->host_address[0] == 0) return (*ss == 0)? OK : FAIL;
1957 if (*ss == 0) return FAIL;
1959 /* If the pattern is precisely "@" then match against the primary host name,
1960 provided that host name matching is permitted; if it's "@[]" match against the
1961 local host's IP addresses. */
1967 if (isiponly) return ERROR;
1968 ss = primary_hostname;
1970 else if (Ustrcmp(ss, "@[]") == 0)
1972 ip_address_item *ip;
1973 for (ip = host_find_interfaces(); ip != NULL; ip = ip->next)
1974 if (Ustrcmp(ip->address, cb->host_address) == 0) return OK;
1979 /* If the pattern is an IP address, optionally followed by a bitmask count, do
1980 a (possibly masked) comparision with the current IP address. */
1982 if (string_is_ip_address(ss, &maskoffset) > 0)
1983 return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL);
1985 /* See if there is a semicolon in the pattern */
1987 semicolon = Ustrchr(ss, ';');
1989 /* If we are doing an IP address only match, then all lookups must be IP
1994 iplookup = semicolon != NULL;
1997 /* Otherwise, if the item is of the form net[n]-lookup;<file|query> then it is
1998 a lookup on a masked IP network, in textual form. The net- stuff really only
1999 applies to single-key lookups where the key is implicit. For query-style
2000 lookups the key is specified in the query. From release 4.30, the use of net-
2001 for query style is no longer needed, but we retain it for backward
2004 else if (Ustrncmp(ss, "net", 3) == 0 && semicolon != NULL)
2007 for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0';
2008 if (mlen == 0 && t == ss+3) mlen = -1; /* No mask supplied */
2009 iplookup = (*t++ == '-');
2012 /* Do the IP address lookup if that is indeed what we have */
2020 uschar *filename, *key, *result;
2023 /* Find the search type */
2025 search_type = search_findtype(t, semicolon - t);
2027 if (search_type < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
2028 search_error_message);
2030 /* Adjust parameters for the type of lookup. For a query-style lookup, there
2031 is no file name, and the "key" is just the query. For query-style with a file
2032 name, we have to fish the file off the start of the query. For a single-key
2033 lookup, the key is the current IP address, masked appropriately, and
2034 reconverted to text form, with the mask appended. For IPv6 addresses, specify
2035 dot separators instead of colons. */
2037 if (mac_islookup(search_type, lookup_absfilequery))
2039 filename = semicolon + 1;
2041 while (*key != 0 && !isspace(*key)) key++;
2042 filename = string_copyn(filename, key - filename);
2043 while (isspace(*key)) key++;
2045 else if (mac_islookup(search_type, lookup_querystyle))
2048 key = semicolon + 1;
2052 insize = host_aton(cb->host_address, incoming);
2053 host_mask(insize, incoming, mlen);
2054 (void)host_nmtoa(insize, incoming, mlen, buffer, '.');
2056 filename = semicolon + 1;
2059 /* Now do the actual lookup; note that there is no search_close() because
2060 of the caching arrangements. */
2062 handle = search_open(filename, search_type, 0, NULL, NULL);
2063 if (handle == NULL) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
2064 search_error_message);
2065 result = search_find(handle, filename, key, -1, NULL, 0, 0, NULL);
2066 if (valueptr != NULL) *valueptr = result;
2067 return (result != NULL)? OK : search_find_defer? DEFER: FAIL;
2070 /* The pattern is not an IP address or network reference of any kind. That is,
2071 it is a host name pattern. If this is an IP only match, there's an error in the
2076 *error = US"cannot match host name in match_ip list";
2080 /* Check the characters of the pattern to see if they comprise only letters,
2081 digits, full stops, and hyphens (the constituents of domain names). Allow
2082 underscores, as they are all too commonly found. Sigh. Also, if
2083 allow_utf8_domains is set, allow top-bit characters. */
2085 for (t = ss; *t != 0; t++)
2086 if (!isalnum(*t) && *t != '.' && *t != '-' && *t != '_' &&
2087 (!allow_utf8_domains || *t < 128)) break;
2089 /* If the pattern is a complete domain name, with no fancy characters, look up
2090 its IP address and match against that. Note that a multi-homed host will add
2091 items to the chain. */
2101 rc = host_find_byname(&h, NULL, NULL, FALSE);
2102 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2105 for (hh = &h; hh != NULL; hh = hh->next)
2107 if (Ustrcmp(hh->address, (Ustrchr(hh->address, ':') == NULL)?
2108 cb->host_ipv4 : cb->host_address) == 0)
2113 if (rc == HOST_FIND_AGAIN) return DEFER;
2114 *error = string_sprintf("failed to find IP address for %s", ss);
2118 /* Almost all subsequent comparisons require the host name, and can be done
2119 using the general string matching function. When this function is called for
2120 outgoing hosts, the name is always given explicitly. If it is NULL, it means we
2121 must use sender_host_name and its aliases, looking them up if necessary. */
2123 if (cb->host_name != NULL) /* Explicit host name given */
2124 return match_check_string(cb->host_name, ss, -1, TRUE, TRUE, TRUE,
2127 /* Host name not given; in principle we need the sender host name and its
2128 aliases. However, for query-style lookups, we do not need the name if the
2129 query does not contain $sender_host_name. From release 4.23, a reference to
2130 $sender_host_name causes it to be looked up, so we don't need to do the lookup
2133 if ((semicolon = Ustrchr(ss, ';')) != NULL)
2136 int partial, affixlen, starflags, id;
2139 id = search_findtype_partial(ss, &partial, &affix, &affixlen, &starflags);
2142 if (id < 0) /* Unknown lookup type */
2144 log_write(0, LOG_MAIN|LOG_PANIC, "%s in host list item \"%s\"",
2145 search_error_message, ss);
2148 isquery = mac_islookup(id, lookup_querystyle|lookup_absfilequery);
2153 switch(match_check_string(US"", ss, -1, TRUE, TRUE, TRUE, valueptr))
2156 case DEFER: return DEFER;
2157 default: return FAIL;
2161 /* Not a query-style lookup; must ensure the host name is present, and then we
2162 do a check on the name and all its aliases. */
2164 if (sender_host_name == NULL)
2166 HDEBUG(D_host_lookup)
2167 debug_printf("sender host name required, to match against %s\n", ss);
2168 if (host_lookup_failed || host_name_lookup() != OK)
2170 *error = string_sprintf("failed to find host name for %s",
2171 sender_host_address);;
2174 host_build_sender_fullhost();
2177 /* Match on the sender host name, using the general matching function */
2179 switch(match_check_string(sender_host_name, ss, -1, TRUE, TRUE, TRUE,
2183 case DEFER: return DEFER;
2186 /* If there are aliases, try matching on them. */
2188 aliases = sender_host_aliases;
2189 while (*aliases != NULL)
2191 switch(match_check_string(*aliases++, ss, -1, TRUE, TRUE, TRUE, valueptr))
2194 case DEFER: return DEFER;
2203 /*************************************************
2204 * Check a specific host matches a host list *
2205 *************************************************/
2207 /* This function is passed a host list containing items in a number of
2208 different formats and the identity of a host. Its job is to determine whether
2209 the given host is in the set of hosts defined by the list. The host name is
2210 passed as a pointer so that it can be looked up if needed and not already
2211 known. This is commonly the case when called from verify_check_host() to check
2212 an incoming connection. When called from elsewhere the host name should usually
2215 This function is now just a front end to match_check_list(), which runs common
2216 code for scanning a list. We pass it the check_host() function to perform a
2220 listptr pointer to the host list
2221 cache_bits pointer to cache for named lists, or NULL
2222 host_name the host name or NULL, implying use sender_host_name and
2223 sender_host_aliases, looking them up if required
2224 host_address the IP address
2225 valueptr if not NULL, data from a lookup is passed back here
2227 Returns: OK if the host is in the defined set
2228 FAIL if the host is not in the defined set,
2229 DEFER if a data lookup deferred (not a host lookup)
2231 If the host name was needed in order to make a comparison, and could not be
2232 determined from the IP address, the result is FAIL unless the item
2233 "+allow_unknown" was met earlier in the list, in which case OK is returned. */
2236 verify_check_this_host(uschar **listptr, unsigned int *cache_bits,
2237 uschar *host_name, uschar *host_address, uschar **valueptr)
2240 unsigned int *local_cache_bits = cache_bits;
2241 uschar *save_host_address = deliver_host_address;
2242 check_host_block cb;
2243 cb.host_name = host_name;
2244 cb.host_address = host_address;
2246 if (valueptr != NULL) *valueptr = NULL;
2248 /* If the host address starts off ::ffff: it is an IPv6 address in
2249 IPv4-compatible mode. Find the IPv4 part for checking against IPv4
2252 cb.host_ipv4 = (Ustrncmp(host_address, "::ffff:", 7) == 0)?
2253 host_address + 7 : host_address;
2255 /* During the running of the check, put the IP address into $host_address. In
2256 the case of calls from the smtp transport, it will already be there. However,
2257 in other calls (e.g. when testing ignore_target_hosts), it won't. Just to be on
2258 the safe side, any existing setting is preserved, though as I write this
2259 (November 2004) I can't see any cases where it is actually needed. */
2261 deliver_host_address = host_address;
2262 rc = match_check_list(
2263 listptr, /* the list */
2264 0, /* separator character */
2265 &hostlist_anchor, /* anchor pointer */
2266 &local_cache_bits, /* cache pointer */
2267 check_host, /* function for testing */
2268 &cb, /* argument for function */
2269 MCL_HOST, /* type of check */
2270 (host_address == sender_host_address)?
2271 US"host" : host_address, /* text for debugging */
2272 valueptr); /* where to pass back data */
2273 deliver_host_address = save_host_address;
2280 /*************************************************
2281 * Check the remote host matches a list *
2282 *************************************************/
2284 /* This is a front end to verify_check_this_host(), created because checking
2285 the remote host is a common occurrence. With luck, a good compiler will spot
2286 the tail recursion and optimize it. If there's no host address, this is
2287 command-line SMTP input - check against an empty string for the address.
2290 listptr pointer to the host list
2292 Returns: the yield of verify_check_this_host(),
2293 i.e. OK, FAIL, or DEFER
2297 verify_check_host(uschar **listptr)
2299 return verify_check_this_host(listptr, sender_host_cache, NULL,
2300 (sender_host_address == NULL)? US"" : sender_host_address, NULL);
2307 /*************************************************
2308 * Invert an IP address for a DNS black list *
2309 *************************************************/
2313 buffer where to put the answer
2314 address the address to invert
2318 invert_address(uschar *buffer, uschar *address)
2321 uschar *bptr = buffer;
2323 /* If this is an IPv4 address mapped into IPv6 format, adjust the pointer
2324 to the IPv4 part only. */
2326 if (Ustrncmp(address, "::ffff:", 7) == 0) address += 7;
2328 /* Handle IPv4 address: when HAVE_IPV6 is false, the result of host_aton() is
2331 if (host_aton(address, bin) == 1)
2335 for (i = 0; i < 4; i++)
2337 sprintf(CS bptr, "%d.", x & 255);
2338 while (*bptr) bptr++;
2343 /* Handle IPv6 address. Actually, as far as I know, there are no IPv6 addresses
2344 in any DNS black lists, and the format in which they will be looked up is
2345 unknown. This is just a guess. */
2351 for (j = 3; j >= 0; j--)
2354 for (i = 0; i < 8; i++)
2356 sprintf(CS bptr, "%x.", x & 15);
2357 while (*bptr) bptr++;
2367 /*************************************************
2368 * Perform a single dnsbl lookup *
2369 *************************************************/
2371 /* This function is called from verify_check_dnsbl() below.
2374 domain the outer dnsbl domain (for debug message)
2375 keydomain the current keydomain (for debug message)
2376 query the domain to be looked up
2377 iplist the list of matching IP addresses
2378 bitmask true if bitmask matching is wanted
2379 invert_result true if result to be inverted
2380 defer_return what to return for a defer
2382 Returns: OK if lookup succeeded
2387 one_check_dnsbl(uschar *domain, uschar *keydomain, uschar *query,
2388 uschar *iplist, BOOL bitmask, BOOL invert_result, int defer_return)
2393 dnsbl_cache_block *cb;
2394 int old_pool = store_pool;
2396 /* Look for this query in the cache. */
2398 t = tree_search(dnsbl_cache, query);
2400 /* If not cached from a previous lookup, we must do a DNS lookup, and
2401 cache the result in permanent memory. */
2405 store_pool = POOL_PERM;
2407 /* Set up a tree entry to cache the lookup */
2409 t = store_get(sizeof(tree_node) + Ustrlen(query));
2410 Ustrcpy(t->name, query);
2411 t->data.ptr = cb = store_get(sizeof(dnsbl_cache_block));
2412 (void)tree_insertnode(&dnsbl_cache, t);
2414 /* Do the DNS loopup . */
2416 HDEBUG(D_dnsbl) debug_printf("new DNS lookup for %s\n", query);
2417 cb->rc = dns_basic_lookup(&dnsa, query, T_A);
2418 cb->text_set = FALSE;
2422 /* If the lookup succeeded, cache the RHS address. The code allows for
2423 more than one address - this was for complete generality and the possible
2424 use of A6 records. However, A6 records have been reduced to experimental
2425 status (August 2001) and may die out. So they may never get used at all,
2426 let alone in dnsbl records. However, leave the code here, just in case.
2428 Quite apart from one A6 RR generating multiple addresses, there are DNS
2429 lists that return more than one A record, so we must handle multiple
2430 addresses generated in that way as well. */
2432 if (cb->rc == DNS_SUCCEED)
2435 dns_address **addrp = &(cb->rhs);
2436 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2438 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
2440 if (rr->type == T_A)
2442 dns_address *da = dns_address_from_rr(&dnsa, rr);
2446 while (da->next != NULL) da = da->next;
2447 addrp = &(da->next);
2452 /* If we didn't find any A records, change the return code. This can
2453 happen when there is a CNAME record but there are no A records for what
2456 if (cb->rhs == NULL) cb->rc = DNS_NODATA;
2459 store_pool = old_pool;
2462 /* Previous lookup was cached */
2466 HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
2470 /* We now have the result of the DNS lookup, either newly done, or cached
2471 from a previous call. If the lookup succeeded, check against the address
2472 list if there is one. This may be a positive equality list (introduced by
2473 "="), a negative equality list (introduced by "!="), a positive bitmask
2474 list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/
2476 if (cb->rc == DNS_SUCCEED)
2478 dns_address *da = NULL;
2479 uschar *addlist = cb->rhs->address;
2481 /* For A and AAAA records, there may be multiple addresses from multiple
2482 records. For A6 records (currently not expected to be used) there may be
2483 multiple addresses from a single record. */
2485 for (da = cb->rhs->next; da != NULL; da = da->next)
2486 addlist = string_sprintf("%s, %s", addlist, da->address);
2488 HDEBUG(D_dnsbl) debug_printf("DNS lookup for %s succeeded (yielding %s)\n",
2491 /* Address list check; this can be either for equality, or via a bitmask.
2492 In the latter case, all the bits must match. */
2498 uschar *ptr = iplist;
2500 while (string_nextinlist(&ptr, &ipsep, ip, sizeof(ip)) != NULL)
2502 /* Handle exact matching */
2505 for (da = cb->rhs; da != NULL; da = da->next)
2507 if (Ustrcmp(CS da->address, ip) == 0) break;
2510 /* Handle bitmask matching */
2516 /* At present, all known DNS blocking lists use A records, with
2517 IPv4 addresses on the RHS encoding the information they return. I
2518 wonder if this will linger on as the last vestige of IPv4 when IPv6
2519 is ubiquitous? Anyway, for now we use paranoia code to completely
2520 ignore IPv6 addresses. The default mask is 0, which always matches.
2521 We change this only for IPv4 addresses in the list. */
2523 if (host_aton(ip, address) == 1) mask = address[0];
2525 /* Scan the returned addresses, skipping any that are IPv6 */
2527 for (da = cb->rhs; da != NULL; da = da->next)
2529 if (host_aton(da->address, address) != 1) continue;
2530 if ((address[0] & mask) == mask) break;
2534 /* Break out if a match has been found */
2536 if (da != NULL) break;
2541 (a) No IP address in a positive list matched, or
2542 (b) An IP address in a negative list did match
2544 then behave as if the DNSBL lookup had not succeeded, i.e. the host is
2547 if (invert_result != (da == NULL))
2551 debug_printf("=> but we are not accepting this block class because\n");
2552 debug_printf("=> there was %s match for %c%s\n",
2553 invert_result? "an exclude":"no", bitmask? '&' : '=', iplist);
2559 /* Either there was no IP list, or the record matched. Look up a TXT record
2560 if it hasn't previously been done. */
2564 cb->text_set = TRUE;
2565 if (dns_basic_lookup(&dnsa, query, T_TXT) == DNS_SUCCEED)
2568 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2570 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
2571 if (rr->type == T_TXT) break;
2574 int len = (rr->data)[0];
2575 if (len > 511) len = 127;
2576 store_pool = POOL_PERM;
2577 cb->text = string_sprintf("%.*s", len, (const uschar *)(rr->data+1));
2578 store_pool = old_pool;
2583 dnslist_value = addlist;
2584 dnslist_text = cb->text;
2588 /* There was a problem with the DNS lookup */
2590 if (cb->rc != DNS_NOMATCH && cb->rc != DNS_NODATA)
2592 log_write(L_dnslist_defer, LOG_MAIN,
2593 "DNS list lookup defer (probably timeout) for %s: %s", query,
2594 (defer_return == OK)? US"assumed in list" :
2595 (defer_return == FAIL)? US"assumed not in list" :
2596 US"returned DEFER");
2597 return defer_return;
2600 /* No entry was found in the DNS; continue for next domain */
2604 debug_printf("DNS lookup for %s failed\n", query);
2605 debug_printf("=> that means %s is not listed at %s\n",
2615 /*************************************************
2616 * Check host against DNS black lists *
2617 *************************************************/
2619 /* This function runs checks against a list of DNS black lists, until one
2620 matches. Each item on the list can be of the form
2622 domain=ip-address/key
2624 The domain is the right-most domain that is used for the query, for example,
2625 blackholes.mail-abuse.org. If the IP address is present, there is a match only
2626 if the DNS lookup returns a matching IP address. Several addresses may be
2627 given, comma-separated, for example: x.y.z=127.0.0.1,127.0.0.2.
2629 If no key is given, what is looked up in the domain is the inverted IP address
2630 of the current client host. If a key is given, it is used to construct the
2631 domain for the lookup. For example,
2633 dsn.rfc-ignorant.org/$sender_address_domain
2635 After finding a match in the DNS, the domain is placed in $dnslist_domain, and
2636 then we check for a TXT record for an error message, and if found, save its
2637 value in $dnslist_text. We also cache everything in a tree, to optimize
2640 Note: an address for testing RBL is 192.203.178.39
2641 Note: an address for testing DUL is 192.203.178.4
2642 Note: a domain for testing RFCI is example.tld.dsn.rfc-ignorant.org
2645 listptr the domain/address/data list
2647 Returns: OK successful lookup (i.e. the address is on the list), or
2648 lookup deferred after +include_unknown
2649 FAIL name not found, or no data found for the given type, or
2650 lookup deferred after +exclude_unknown (default)
2651 DEFER lookup failure, if +defer_unknown was set
2655 verify_check_dnsbl(uschar **listptr)
2658 int defer_return = FAIL;
2659 BOOL invert_result = FALSE;
2660 uschar *list = *listptr;
2663 uschar buffer[1024];
2664 uschar query[256]; /* DNS domain max length */
2665 uschar revadd[128]; /* Long enough for IPv6 address */
2667 /* Indicate that the inverted IP address is not yet set up */
2671 /* In case this is the first time the DNS resolver is being used. */
2673 dns_init(FALSE, FALSE);
2675 /* Loop through all the domains supplied, until something matches */
2677 while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
2681 BOOL bitmask = FALSE;
2685 HDEBUG(D_dnsbl) debug_printf("DNS list check: %s\n", domain);
2687 /* Deal with special values that change the behaviour on defer */
2689 if (domain[0] == '+')
2691 if (strcmpic(domain, US"+include_unknown") == 0) defer_return = OK;
2692 else if (strcmpic(domain, US"+exclude_unknown") == 0) defer_return = FAIL;
2693 else if (strcmpic(domain, US"+defer_unknown") == 0) defer_return = DEFER;
2695 log_write(0, LOG_MAIN|LOG_PANIC, "unknown item in dnslist (ignored): %s",
2700 /* See if there's explicit data to be looked up */
2702 key = Ustrchr(domain, '/');
2703 if (key != NULL) *key++ = 0;
2705 /* See if there's a list of addresses supplied after the domain name. This is
2706 introduced by an = or a & character; if preceded by ! we invert the result.
2709 iplist = Ustrchr(domain, '=');
2713 iplist = Ustrchr(domain, '&');
2718 if (iplist > domain && iplist[-1] == '!')
2720 invert_result = TRUE;
2726 /* Check that what we have left is a sensible domain name. There is no reason
2727 why these domains should in fact use the same syntax as hosts and email
2728 domains, but in practice they seem to. However, there is little point in
2729 actually causing an error here, because that would no doubt hold up incoming
2730 mail. Instead, I'll just log it. */
2732 for (s = domain; *s != 0; s++)
2734 if (!isalnum(*s) && *s != '-' && *s != '.')
2736 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
2737 "strange characters - is this right?", domain);
2742 /* If there is no key string, construct the query by adding the domain name
2743 onto the inverted host address, and perform a single DNS lookup. */
2747 if (sender_host_address == NULL) return FAIL; /* can never match */
2748 if (revadd[0] == 0) invert_address(revadd, sender_host_address);
2749 frc = string_format(query, sizeof(query), "%s%s", revadd, domain);
2753 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
2754 "(ignored): %s...", query);
2758 rc = one_check_dnsbl(domain, sender_host_address, query, iplist, bitmask,
2759 invert_result, defer_return);
2763 dnslist_domain = string_copy(domain);
2764 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
2765 sender_host_address, domain);
2768 if (rc != FAIL) return rc; /* OK or DEFER */
2771 /* If there is a key string, it can be a list of domains or IP addresses to
2772 be concatenated with the main domain. */
2779 uschar keybuffer[256];
2781 while ((keydomain = string_nextinlist(&key, &keysep, keybuffer,
2782 sizeof(keybuffer))) != NULL)
2784 if (string_is_ip_address(keydomain, NULL) > 0)
2786 uschar keyrevadd[128];
2787 invert_address(keyrevadd, keydomain);
2788 frc = string_format(query, sizeof(query), "%s%s", keyrevadd, domain);
2792 frc = string_format(query, sizeof(query), "%s.%s", keydomain, domain);
2797 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
2798 "(ignored): %s...", query);
2802 rc = one_check_dnsbl(domain, keydomain, query, iplist, bitmask,
2803 invert_result, defer_return);
2807 dnslist_domain = string_copy(domain);
2808 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
2813 /* If the lookup deferred, remember this fact. We keep trying the rest
2814 of the list to see if we get a useful result, and if we don't, we return
2815 DEFER at the end. */
2817 if (rc == DEFER) defer = TRUE;
2818 } /* continue with next keystring domain/address */
2820 if (defer) return DEFER;
2822 } /* continue with next dnsdb outer domain */
2827 /* End of verify.c */