1 /* $Cambridge: exim/src/src/verify.c,v 1.38 2006/09/05 13:24:10 ph10 Exp $ */
3 /*************************************************
4 * Exim - an Internet mail transport agent *
5 *************************************************/
7 /* Copyright (c) University of Cambridge 1995 - 2006 */
8 /* See the file NOTICE for conditions of use and distribution. */
10 /* Functions concerned with verifying things. The original code for callout
11 caching was contributed by Kevin Fleming (but I hacked it around a bit). */
17 /* Structure for caching DNSBL lookups */
19 typedef struct dnsbl_cache_block {
27 /* Anchor for DNSBL cache */
29 static tree_node *dnsbl_cache = NULL;
33 /*************************************************
34 * Retrieve a callout cache record *
35 *************************************************/
37 /* If a record exists, check whether it has expired.
40 dbm_file an open hints file
42 type "address" or "domain"
43 positive_expire expire time for positive records
44 negative_expire expire time for negative records
46 Returns: the cache record if a non-expired one exists, else NULL
49 static dbdata_callout_cache *
50 get_callout_cache_record(open_db *dbm_file, uschar *key, uschar *type,
51 int positive_expire, int negative_expire)
56 dbdata_callout_cache *cache_record;
58 cache_record = dbfn_read_with_length(dbm_file, key, &length);
60 if (cache_record == NULL)
62 HDEBUG(D_verify) debug_printf("callout cache: no %s record found\n", type);
66 /* We treat a record as "negative" if its result field is not positive, or if
67 it is a domain record and the postmaster field is negative. */
69 negative = cache_record->result != ccache_accept ||
70 (type[0] == 'd' && cache_record->postmaster_result == ccache_reject);
71 expire = negative? negative_expire : positive_expire;
74 if (now - cache_record->time_stamp > expire)
76 HDEBUG(D_verify) debug_printf("callout cache: %s record expired\n", type);
80 /* If this is a non-reject domain record, check for the obsolete format version
81 that doesn't have the postmaster and random timestamps, by looking at the
82 length. If so, copy it to a new-style block, replicating the record's
83 timestamp. Then check the additional timestamps. (There's no point wasting
84 effort if connections are rejected.) */
86 if (type[0] == 'd' && cache_record->result != ccache_reject)
88 if (length == sizeof(dbdata_callout_cache_obs))
90 dbdata_callout_cache *new = store_get(sizeof(dbdata_callout_cache));
91 memcpy(new, cache_record, length);
92 new->postmaster_stamp = new->random_stamp = new->time_stamp;
96 if (now - cache_record->postmaster_stamp > expire)
97 cache_record->postmaster_result = ccache_unknown;
99 if (now - cache_record->random_stamp > expire)
100 cache_record->random_result = ccache_unknown;
103 HDEBUG(D_verify) debug_printf("callout cache: found %s record\n", type);
109 /*************************************************
110 * Do callout verification for an address *
111 *************************************************/
113 /* This function is called from verify_address() when the address has routed to
114 a host list, and a callout has been requested. Callouts are expensive; that is
115 why a cache is used to improve the efficiency.
118 addr the address that's been routed
119 host_list the list of hosts to try
120 tf the transport feedback block
122 ifstring "interface" option from transport, or NULL
123 portstring "port" option from transport, or NULL
124 protocolstring "protocol" option from transport, or NULL
125 callout the per-command callout timeout
126 callout_overall the overall callout timeout (if < 0 use 4*callout)
127 callout_connect the callout connection timeout (if < 0 use callout)
128 options the verification options - these bits are used:
129 vopt_is_recipient => this is a recipient address
130 vopt_callout_no_cache => don't use callout cache
131 vopt_callout_fullpm => if postmaster check, do full one
132 vopt_callout_random => do the "random" thing
133 vopt_callout_recipsender => use real sender for recipient
134 vopt_callout_recippmaster => use postmaster for recipient
135 se_mailfrom MAIL FROM address for sender verify; NULL => ""
136 pm_mailfrom if non-NULL, do the postmaster check with this sender
138 Returns: OK/FAIL/DEFER
142 do_callout(address_item *addr, host_item *host_list, transport_feedback *tf,
143 int callout, int callout_overall, int callout_connect, int options,
144 uschar *se_mailfrom, uschar *pm_mailfrom)
146 BOOL is_recipient = (options & vopt_is_recipient) != 0;
147 BOOL callout_no_cache = (options & vopt_callout_no_cache) != 0;
148 BOOL callout_random = (options & vopt_callout_random) != 0;
151 int old_domain_cache_result = ccache_accept;
154 uschar *from_address;
155 uschar *random_local_part = NULL;
156 uschar *save_deliver_domain = deliver_domain;
157 uschar **failure_ptr = is_recipient?
158 &recipient_verify_failure : &sender_verify_failure;
160 open_db *dbm_file = NULL;
161 dbdata_callout_cache new_domain_record;
162 dbdata_callout_cache_address new_address_record;
164 time_t callout_start_time;
166 new_domain_record.result = ccache_unknown;
167 new_domain_record.postmaster_result = ccache_unknown;
168 new_domain_record.random_result = ccache_unknown;
170 memset(&new_address_record, 0, sizeof(new_address_record));
172 /* For a recipient callout, the key used for the address cache record must
173 include the sender address if we are using the real sender in the callout,
174 because that may influence the result of the callout. */
176 address_key = addr->address;
181 if ((options & vopt_callout_recipsender) != 0)
183 address_key = string_sprintf("%s/<%s>", addr->address, sender_address);
184 from_address = sender_address;
186 else if ((options & vopt_callout_recippmaster) != 0)
188 address_key = string_sprintf("%s/<postmaster@%s>", addr->address,
189 qualify_domain_sender);
190 from_address = string_sprintf("postmaster@%s", qualify_domain_sender);
194 /* For a sender callout, we must adjust the key if the mailfrom address is not
199 from_address = (se_mailfrom == NULL)? US"" : se_mailfrom;
200 if (from_address[0] != 0)
201 address_key = string_sprintf("%s/<%s>", addr->address, from_address);
204 /* Open the callout cache database, it it exists, for reading only at this
205 stage, unless caching has been disabled. */
207 if (callout_no_cache)
209 HDEBUG(D_verify) debug_printf("callout cache: disabled by no_cache\n");
211 else if ((dbm_file = dbfn_open(US"callout", O_RDWR, &dbblock, FALSE)) == NULL)
213 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
216 /* If a cache database is available see if we can avoid the need to do an
217 actual callout by making use of previously-obtained data. */
219 if (dbm_file != NULL)
221 dbdata_callout_cache_address *cache_address_record;
222 dbdata_callout_cache *cache_record = get_callout_cache_record(dbm_file,
223 addr->domain, US"domain",
224 callout_cache_domain_positive_expire,
225 callout_cache_domain_negative_expire);
227 /* If an unexpired cache record was found for this domain, see if the callout
228 process can be short-circuited. */
230 if (cache_record != NULL)
232 /* In most cases, if an early command (up to and including MAIL FROM:<>)
233 was rejected, there is no point carrying on. The callout fails. However, if
234 we are doing a recipient verification with use_sender or use_postmaster
235 set, a previous failure of MAIL FROM:<> doesn't count, because this time we
236 will be using a non-empty sender. We have to remember this situation so as
237 not to disturb the cached domain value if this whole verification succeeds
238 (we don't want it turning into "accept"). */
240 old_domain_cache_result = cache_record->result;
242 if (cache_record->result == ccache_reject ||
243 (*from_address == 0 && cache_record->result == ccache_reject_mfnull))
245 setflag(addr, af_verify_nsfail);
247 debug_printf("callout cache: domain gave initial rejection, or "
248 "does not accept HELO or MAIL FROM:<>\n");
249 setflag(addr, af_verify_nsfail);
250 addr->user_message = US"(result of an earlier callout reused).";
252 *failure_ptr = US"mail";
256 /* If a previous check on a "random" local part was accepted, we assume
257 that the server does not do any checking on local parts. There is therefore
258 no point in doing the callout, because it will always be successful. If a
259 random check previously failed, arrange not to do it again, but preserve
260 the data in the new record. If a random check is required but hasn't been
261 done, skip the remaining cache processing. */
263 if (callout_random) switch(cache_record->random_result)
267 debug_printf("callout cache: domain accepts random addresses\n");
268 goto END_CALLOUT; /* Default yield is OK */
272 debug_printf("callout cache: domain rejects random addresses\n");
273 callout_random = FALSE;
274 new_domain_record.random_result = ccache_reject;
275 new_domain_record.random_stamp = cache_record->random_stamp;
280 debug_printf("callout cache: need to check random address handling "
281 "(not cached or cache expired)\n");
285 /* If a postmaster check is requested, but there was a previous failure,
286 there is again no point in carrying on. If a postmaster check is required,
287 but has not been done before, we are going to have to do a callout, so skip
288 remaining cache processing. */
290 if (pm_mailfrom != NULL)
292 if (cache_record->postmaster_result == ccache_reject)
294 setflag(addr, af_verify_pmfail);
296 debug_printf("callout cache: domain does not accept "
297 "RCPT TO:<postmaster@domain>\n");
299 *failure_ptr = US"postmaster";
300 setflag(addr, af_verify_pmfail);
301 addr->user_message = US"(result of earlier verification reused).";
304 if (cache_record->postmaster_result == ccache_unknown)
307 debug_printf("callout cache: need to check RCPT "
308 "TO:<postmaster@domain> (not cached or cache expired)\n");
312 /* If cache says OK, set pm_mailfrom NULL to prevent a redundant
313 postmaster check if the address itself has to be checked. Also ensure
314 that the value in the cache record is preserved (with its old timestamp).
317 HDEBUG(D_verify) debug_printf("callout cache: domain accepts RCPT "
318 "TO:<postmaster@domain>\n");
320 new_domain_record.postmaster_result = ccache_accept;
321 new_domain_record.postmaster_stamp = cache_record->postmaster_stamp;
325 /* We can't give a result based on information about the domain. See if there
326 is an unexpired cache record for this specific address (combined with the
327 sender address if we are doing a recipient callout with a non-empty sender).
330 cache_address_record = (dbdata_callout_cache_address *)
331 get_callout_cache_record(dbm_file,
332 address_key, US"address",
333 callout_cache_positive_expire,
334 callout_cache_negative_expire);
336 if (cache_address_record != NULL)
338 if (cache_address_record->result == ccache_accept)
341 debug_printf("callout cache: address record is positive\n");
346 debug_printf("callout cache: address record is negative\n");
347 addr->user_message = US"Previous (cached) callout verification failure";
348 *failure_ptr = US"recipient";
354 /* Close the cache database while we actually do the callout for real. */
357 dbfn_close(dbm_file);
361 /* The information wasn't available in the cache, so we have to do a real
362 callout and save the result in the cache for next time, unless no_cache is set,
363 or unless we have a previously cached negative random result. If we are to test
364 with a random local part, ensure that such a local part is available. If not,
365 log the fact, but carry on without randomming. */
367 if (callout_random && callout_random_local_part != NULL)
369 random_local_part = expand_string(callout_random_local_part);
370 if (random_local_part == NULL)
371 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand "
372 "callout_random_local_part: %s", expand_string_message);
375 /* Default the connect and overall callout timeouts if not set, and record the
376 time we are starting so that we can enforce it. */
378 if (callout_overall < 0) callout_overall = 4 * callout;
379 if (callout_connect < 0) callout_connect = callout;
380 callout_start_time = time(NULL);
382 /* Now make connections to the hosts and do real callouts. The list of hosts
383 is passed in as an argument. */
385 for (host = host_list; host != NULL && !done; host = host->next)
387 smtp_inblock inblock;
388 smtp_outblock outblock;
391 BOOL send_quit = TRUE;
392 uschar *helo = US"HELO";
393 uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
394 uschar inbuffer[4096];
395 uschar outbuffer[1024];
396 uschar responsebuffer[4096];
398 clearflag(addr, af_verify_pmfail); /* postmaster callout flag */
399 clearflag(addr, af_verify_nsfail); /* null sender callout flag */
401 /* Skip this host if we don't have an IP address for it. */
403 if (host->address == NULL)
405 DEBUG(D_verify) debug_printf("no IP address for host name %s: skipping\n",
410 /* Check the overall callout timeout */
412 if (time(NULL) - callout_start_time >= callout_overall)
414 HDEBUG(D_verify) debug_printf("overall timeout for callout exceeded\n");
418 /* Set IPv4 or IPv6 */
420 host_af = (Ustrchr(host->address, ':') == NULL)? AF_INET:AF_INET6;
422 /* Expand and interpret the interface and port strings. The latter will not
423 be used if there is a host-specific port (e.g. from a manualroute router).
424 This has to be delayed till now, because they may expand differently for
425 different hosts. If there's a failure, log it, but carry on with the
428 deliver_host = host->name;
429 deliver_host_address = host->address;
430 deliver_domain = addr->domain;
432 if (!smtp_get_interface(tf->interface, host_af, addr, NULL, &interface,
434 !smtp_get_port(tf->port, addr, &port, US"callout"))
435 log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address,
438 deliver_host = deliver_host_address = NULL;
439 deliver_domain = save_deliver_domain;
441 /* Set HELO string according to the protocol */
443 if (Ustrcmp(tf->protocol, "lmtp") == 0) helo = US"LHLO";
445 HDEBUG(D_verify) debug_printf("interface=%s port=%d\n", interface, port);
447 /* Set up the buffer for reading SMTP response packets. */
449 inblock.buffer = inbuffer;
450 inblock.buffersize = sizeof(inbuffer);
451 inblock.ptr = inbuffer;
452 inblock.ptrend = inbuffer;
454 /* Set up the buffer for holding SMTP commands while pipelining */
456 outblock.buffer = outbuffer;
457 outblock.buffersize = sizeof(outbuffer);
458 outblock.ptr = outbuffer;
459 outblock.cmd_count = 0;
460 outblock.authenticating = FALSE;
462 /* Connect to the host; on failure, just loop for the next one, but we
463 set the error for the last one. Use the callout_connect timeout. */
465 inblock.sock = outblock.sock =
466 smtp_connect(host, host_af, port, interface, callout_connect, TRUE);
467 if (inblock.sock < 0)
469 addr->message = string_sprintf("could not connect to %s [%s]: %s",
470 host->name, host->address, strerror(errno));
474 /* Wait for initial response, and send HELO. The smtp_write_command()
475 function leaves its command in big_buffer. This is used in error responses.
476 Initialize it in case the connection is rejected. */
478 Ustrcpy(big_buffer, "initial connection");
481 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
483 smtp_write_command(&outblock, FALSE, "%s %s\r\n", helo,
484 smtp_active_hostname) >= 0 &&
485 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
488 /* Failure to accept HELO is cached; this blocks the whole domain for all
489 senders. I/O errors and defer responses are not cached. */
493 *failure_ptr = US"mail"; /* At or before MAIL */
494 if (errno == 0 && responsebuffer[0] == '5')
496 setflag(addr, af_verify_nsfail);
497 new_domain_record.result = ccache_reject;
501 /* Send the MAIL command */
504 smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>\r\n",
505 from_address) >= 0 &&
506 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
509 /* If the host does not accept MAIL FROM:<>, arrange to cache this
510 information, but again, don't record anything for an I/O error or a defer. Do
511 not cache rejections of MAIL when a non-empty sender has been used, because
512 that blocks the whole domain for all senders. */
516 *failure_ptr = US"mail"; /* At or before MAIL */
517 if (errno == 0 && responsebuffer[0] == '5')
519 setflag(addr, af_verify_nsfail);
520 if (from_address[0] == 0)
521 new_domain_record.result = ccache_reject_mfnull;
525 /* Otherwise, proceed to check a "random" address (if required), then the
526 given address, and the postmaster address (if required). Between each check,
527 issue RSET, because some servers accept only one recipient after MAIL
530 Before doing this, set the result in the domain cache record to "accept",
531 unless its previous value was ccache_reject_mfnull. In that case, the domain
532 rejects MAIL FROM:<> and we want to continue to remember that. When that is
533 the case, we have got here only in the case of a recipient verification with
534 a non-null sender. */
538 new_domain_record.result =
539 (old_domain_cache_result == ccache_reject_mfnull)?
540 ccache_reject_mfnull: ccache_accept;
542 /* Do the random local part check first */
544 if (random_local_part != NULL)
546 uschar randombuffer[1024];
548 smtp_write_command(&outblock, FALSE,
549 "RCPT TO:<%.1000s@%.1000s>\r\n", random_local_part,
550 addr->domain) >= 0 &&
551 smtp_read_response(&inblock, randombuffer,
552 sizeof(randombuffer), '2', callout);
554 /* Remember when we last did a random test */
556 new_domain_record.random_stamp = time(NULL);
558 /* If accepted, we aren't going to do any further tests below. */
562 new_domain_record.random_result = ccache_accept;
565 /* Otherwise, cache a real negative response, and get back to the right
566 state to send RCPT. Unless there's some problem such as a dropped
567 connection, we expect to succeed, because the commands succeeded above. */
571 if (randombuffer[0] == '5')
572 new_domain_record.random_result = ccache_reject;
575 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
576 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
579 smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>\r\n",
580 from_address) >= 0 &&
581 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
584 else done = FALSE; /* Some timeout/connection problem */
587 /* If the host is accepting all local parts, as determined by the "random"
588 check, we don't need to waste time doing any further checking. */
590 if (new_domain_record.random_result != ccache_accept && done)
592 /* Get the rcpt_include_affixes flag from the transport if there is one,
593 but assume FALSE if there is not. */
596 smtp_write_command(&outblock, FALSE, "RCPT TO:<%.1000s>\r\n",
597 transport_rcpt_address(addr,
598 (addr->transport == NULL)? FALSE :
599 addr->transport->rcpt_include_affixes)) >= 0 &&
600 smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
604 new_address_record.result = ccache_accept;
605 else if (errno == 0 && responsebuffer[0] == '5')
607 *failure_ptr = US"recipient";
608 new_address_record.result = ccache_reject;
611 /* Do postmaster check if requested; if a full check is required, we
612 check for RCPT TO:<postmaster> (no domain) in accordance with RFC 821. */
614 if (done && pm_mailfrom != NULL)
617 smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
618 smtp_read_response(&inblock, responsebuffer,
619 sizeof(responsebuffer), '2', callout) &&
621 smtp_write_command(&outblock, FALSE,
622 "MAIL FROM:<%s>\r\n", pm_mailfrom) >= 0 &&
623 smtp_read_response(&inblock, responsebuffer,
624 sizeof(responsebuffer), '2', callout) &&
626 /* First try using the current domain */
629 smtp_write_command(&outblock, FALSE,
630 "RCPT TO:<postmaster@%.1000s>\r\n", addr->domain) >= 0 &&
631 smtp_read_response(&inblock, responsebuffer,
632 sizeof(responsebuffer), '2', callout)
637 /* If that doesn't work, and a full check is requested,
638 try without the domain. */
641 (options & vopt_callout_fullpm) != 0 &&
642 smtp_write_command(&outblock, FALSE,
643 "RCPT TO:<postmaster>\r\n") >= 0 &&
644 smtp_read_response(&inblock, responsebuffer,
645 sizeof(responsebuffer), '2', callout)
648 /* Sort out the cache record */
650 new_domain_record.postmaster_stamp = time(NULL);
653 new_domain_record.postmaster_result = ccache_accept;
654 else if (errno == 0 && responsebuffer[0] == '5')
656 *failure_ptr = US"postmaster";
657 setflag(addr, af_verify_pmfail);
658 new_domain_record.postmaster_result = ccache_reject;
661 } /* Random not accepted */
662 } /* MAIL FROM: accepted */
664 /* For any failure of the main check, other than a negative response, we just
665 close the connection and carry on. We can identify a negative response by the
666 fact that errno is zero. For I/O errors it will be non-zero
668 Set up different error texts for logging and for sending back to the caller
669 as an SMTP response. Log in all cases, using a one-line format. For sender
670 callouts, give a full response to the caller, but for recipient callouts,
671 don't give the IP address because this may be an internal host whose identity
672 is not to be widely broadcast. */
676 if (errno == ETIMEDOUT)
678 HDEBUG(D_verify) debug_printf("SMTP timeout\n");
683 if (*responsebuffer == 0) Ustrcpy(responsebuffer, US"connection dropped");
686 string_sprintf("response to \"%s\" from %s [%s] was: %s",
687 big_buffer, host->name, host->address,
688 string_printing(responsebuffer));
690 addr->user_message = is_recipient?
691 string_sprintf("Callout verification failed:\n%s", responsebuffer)
693 string_sprintf("Called: %s\nSent: %s\nResponse: %s",
694 host->address, big_buffer, responsebuffer);
696 /* Hard rejection ends the process */
698 if (responsebuffer[0] == '5') /* Address rejected */
706 /* End the SMTP conversation and close the connection. */
708 if (send_quit) (void)smtp_write_command(&outblock, FALSE, "QUIT\r\n");
709 (void)close(inblock.sock);
710 } /* Loop through all hosts, while !done */
712 /* If we get here with done == TRUE, a successful callout happened, and yield
713 will be set OK or FAIL according to the response to the RCPT command.
714 Otherwise, we looped through the hosts but couldn't complete the business.
715 However, there may be domain-specific information to cache in both cases.
717 The value of the result field in the new_domain record is ccache_unknown if
718 there was an error before or with MAIL FROM:, and errno was not zero,
719 implying some kind of I/O error. We don't want to write the cache in that case.
720 Otherwise the value is ccache_accept, ccache_reject, or ccache_reject_mfnull. */
722 if (!callout_no_cache && new_domain_record.result != ccache_unknown)
724 if ((dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE))
727 HDEBUG(D_verify) debug_printf("callout cache: not available\n");
731 (void)dbfn_write(dbm_file, addr->domain, &new_domain_record,
732 (int)sizeof(dbdata_callout_cache));
733 HDEBUG(D_verify) debug_printf("wrote callout cache domain record:\n"
734 " result=%d postmaster=%d random=%d\n",
735 new_domain_record.result,
736 new_domain_record.postmaster_result,
737 new_domain_record.random_result);
741 /* If a definite result was obtained for the callout, cache it unless caching
746 if (!callout_no_cache && new_address_record.result != ccache_unknown)
748 if (dbm_file == NULL)
749 dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE);
750 if (dbm_file == NULL)
752 HDEBUG(D_verify) debug_printf("no callout cache available\n");
756 (void)dbfn_write(dbm_file, address_key, &new_address_record,
757 (int)sizeof(dbdata_callout_cache_address));
758 HDEBUG(D_verify) debug_printf("wrote %s callout cache address record\n",
759 (new_address_record.result == ccache_accept)? "positive" : "negative");
764 /* Failure to connect to any host, or any response other than 2xx or 5xx is a
765 temporary error. If there was only one host, and a response was received, leave
766 it alone if supplying details. Otherwise, give a generic response. */
770 uschar *dullmsg = string_sprintf("Could not complete %s verify callout",
771 is_recipient? "recipient" : "sender");
774 if (host_list->next != NULL || addr->message == NULL) addr->message = dullmsg;
776 addr->user_message = (!smtp_return_error_details)? dullmsg :
777 string_sprintf("%s for <%s>.\n"
778 "The mail server(s) for the domain may be temporarily unreachable, or\n"
779 "they may be permanently unreachable from this server. In the latter case,\n%s",
780 dullmsg, addr->address,
782 "the address will never be accepted."
784 "you need to change the address or create an MX record for its domain\n"
785 "if it is supposed to be generally accessible from the Internet.\n"
786 "Talk to your mail administrator for details.");
788 /* Force a specific error code */
790 addr->basic_errno = ERRNO_CALLOUTDEFER;
793 /* Come here from within the cache-reading code on fast-track exit. */
796 if (dbm_file != NULL) dbfn_close(dbm_file);
802 /*************************************************
803 * Copy error to toplevel address *
804 *************************************************/
806 /* This function is used when a verify fails or defers, to ensure that the
807 failure or defer information is in the original toplevel address. This applies
808 when an address is redirected to a single new address, and the failure or
809 deferral happens to the child address.
812 vaddr the verify address item
813 addr the final address item
816 Returns: the value of YIELD
820 copy_error(address_item *vaddr, address_item *addr, int yield)
824 vaddr->message = addr->message;
825 vaddr->user_message = addr->user_message;
826 vaddr->basic_errno = addr->basic_errno;
827 vaddr->more_errno = addr->more_errno;
828 vaddr->p.address_data = addr->p.address_data;
836 /*************************************************
837 * Verify an email address *
838 *************************************************/
840 /* This function is used both for verification (-bv and at other times) and
841 address testing (-bt), which is indicated by address_test_mode being set.
844 vaddr contains the address to verify; the next field in this block
846 f if not NULL, write the result to this file
847 options various option bits:
848 vopt_fake_sender => this sender verify is not for the real
849 sender (it was verify=sender=xxxx or an address from a
850 header line) - rewriting must not change sender_address
851 vopt_is_recipient => this is a recipient address, otherwise
852 it's a sender address - this affects qualification and
853 rewriting and messages from callouts
854 vopt_qualify => qualify an unqualified address; else error
855 vopt_expn => called from SMTP EXPN command
856 vopt_success_on_redirect => when a new address is generated
857 the verification instantly succeeds
859 These ones are used by do_callout() -- the options variable
862 vopt_callout_fullpm => if postmaster check, do full one
863 vopt_callout_no_cache => don't use callout cache
864 vopt_callout_random => do the "random" thing
865 vopt_callout_recipsender => use real sender for recipient
866 vopt_callout_recippmaster => use postmaster for recipient
868 callout if > 0, specifies that callout is required, and gives timeout
869 for individual commands
870 callout_overall if > 0, gives overall timeout for the callout function;
871 if < 0, a default is used (see do_callout())
872 callout_connect the connection timeout for callouts
873 se_mailfrom when callout is requested to verify a sender, use this
874 in MAIL FROM; NULL => ""
875 pm_mailfrom when callout is requested, if non-NULL, do the postmaster
876 thing and use this as the sender address (may be "")
878 routed if not NULL, set TRUE if routing succeeded, so we can
879 distinguish between routing failed and callout failed
881 Returns: OK address verified
882 FAIL address failed to verify
883 DEFER can't tell at present
887 verify_address(address_item *vaddr, FILE *f, int options, int callout,
888 int callout_overall, int callout_connect, uschar *se_mailfrom,
889 uschar *pm_mailfrom, BOOL *routed)
892 BOOL full_info = (f == NULL)? FALSE : (debug_selector != 0);
893 BOOL is_recipient = (options & vopt_is_recipient) != 0;
894 BOOL expn = (options & vopt_expn) != 0;
895 BOOL success_on_redirect = (options & vopt_success_on_redirect) != 0;
898 int verify_type = expn? v_expn :
899 address_test_mode? v_none :
900 is_recipient? v_recipient : v_sender;
901 address_item *addr_list;
902 address_item *addr_new = NULL;
903 address_item *addr_remote = NULL;
904 address_item *addr_local = NULL;
905 address_item *addr_succeed = NULL;
906 uschar **failure_ptr = is_recipient?
907 &recipient_verify_failure : &sender_verify_failure;
908 uschar *ko_prefix, *cr;
909 uschar *address = vaddr->address;
911 uschar null_sender[] = { 0 }; /* Ensure writeable memory */
913 /* Clear, just in case */
917 /* Set up a prefix and suffix for error message which allow us to use the same
918 output statements both in EXPN mode (where an SMTP response is needed) and when
919 debugging with an output file. */
923 ko_prefix = US"553 ";
926 else ko_prefix = cr = US"";
928 /* Add qualify domain if permitted; otherwise an unqualified address fails. */
930 if (parse_find_at(address) == NULL)
932 if ((options & vopt_qualify) == 0)
935 fprintf(f, "%sA domain is required for \"%s\"%s\n", ko_prefix, address,
937 *failure_ptr = US"qualify";
940 address = rewrite_address_qualify(address, is_recipient);
945 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
946 debug_printf("%s %s\n", address_test_mode? "Testing" : "Verifying", address);
949 /* Rewrite and report on it. Clear the domain and local part caches - these
950 may have been set by domains and local part tests during an ACL. */
952 if (global_rewrite_rules != NULL)
954 uschar *old = address;
955 address = rewrite_address(address, is_recipient, FALSE,
956 global_rewrite_rules, rewrite_existflags);
959 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->localpart_cache[i] = 0;
960 for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->domain_cache[i] = 0;
961 if (f != NULL && !expn) fprintf(f, "Address rewritten as: %s\n", address);
965 /* If this is the real sender address, we must update sender_address at
966 this point, because it may be referred to in the routers. */
968 if ((options & (vopt_fake_sender|vopt_is_recipient)) == 0)
969 sender_address = address;
971 /* If the address was rewritten to <> no verification can be done, and we have
972 to return OK. This rewriting is permitted only for sender addresses; for other
973 addresses, such rewriting fails. */
975 if (address[0] == 0) return OK;
977 /* Save a copy of the sender address for re-instating if we change it to <>
978 while verifying a sender address (a nice bit of self-reference there). */
980 save_sender = sender_address;
982 /* Update the address structure with the possibly qualified and rewritten
983 address. Set it up as the starting address on the chain of new addresses. */
985 vaddr->address = address;
988 /* We need a loop, because an address can generate new addresses. We must also
989 cope with generated pipes and files at the top level. (See also the code and
990 comment in deliver.c.) However, it is usually the case that the router for
991 user's .forward files has its verify flag turned off.
993 If an address generates more than one child, the loop is used only when
994 full_info is set, and this can only be set locally. Remote enquiries just get
995 information about the top level address, not anything that it generated. */
997 while (addr_new != NULL)
1000 address_item *addr = addr_new;
1002 addr_new = addr->next;
1007 debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
1008 debug_printf("Considering %s\n", addr->address);
1011 /* Handle generated pipe, file or reply addresses. We don't get these
1012 when handling EXPN, as it does only one level of expansion. */
1014 if (testflag(addr, af_pfr))
1021 if (addr->address[0] == '>')
1023 allow = testflag(addr, af_allow_reply);
1024 fprintf(f, "%s -> mail %s", addr->parent->address, addr->address + 1);
1028 allow = (addr->address[0] == '|')?
1029 testflag(addr, af_allow_pipe) : testflag(addr, af_allow_file);
1030 fprintf(f, "%s -> %s", addr->parent->address, addr->address);
1033 if (addr->basic_errno == ERRNO_BADTRANSPORT)
1034 fprintf(f, "\n*** Error in setting up pipe, file, or autoreply:\n"
1035 "%s\n", addr->message);
1037 fprintf(f, "\n transport = %s\n", addr->transport->name);
1039 fprintf(f, " *** forbidden ***\n");
1044 /* Just in case some router parameter refers to it. */
1046 return_path = (addr->p.errors_address != NULL)?
1047 addr->p.errors_address : sender_address;
1049 /* Split the address into domain and local part, handling the %-hack if
1050 necessary, and then route it. While routing a sender address, set
1051 $sender_address to <> because that is what it will be if we were trying to
1052 send a bounce to the sender. */
1054 if (routed != NULL) *routed = FALSE;
1055 if ((rc = deliver_split_address(addr)) == OK)
1057 if (!is_recipient) sender_address = null_sender;
1058 rc = route_address(addr, &addr_local, &addr_remote, &addr_new,
1059 &addr_succeed, verify_type);
1060 sender_address = save_sender; /* Put back the real sender */
1063 /* If routing an address succeeded, set the flag that remembers, for use when
1064 an ACL cached a sender verify (in case a callout fails). Then if routing set
1065 up a list of hosts or the transport has a host list, and the callout option
1066 is set, and we aren't in a host checking run, do the callout verification,
1067 and set another flag that notes that a callout happened. */
1071 if (routed != NULL) *routed = TRUE;
1074 host_item *host_list = addr->host_list;
1076 /* Default, if no remote transport, to NULL for the interface (=> any),
1077 "smtp" for the port, and "smtp" for the protocol. */
1079 transport_feedback tf = { NULL, US"smtp", US"smtp", NULL, FALSE, FALSE };
1081 /* If verification yielded a remote transport, we want to use that
1082 transport's options, so as to mimic what would happen if we were really
1083 sending a message to this address. */
1085 if (addr->transport != NULL && !addr->transport->info->local)
1087 (void)(addr->transport->setup)(addr->transport, addr, &tf, 0, 0, NULL);
1089 /* If the transport has hosts and the router does not, or if the
1090 transport is configured to override the router's hosts, we must build a
1091 host list of the transport's hosts, and find the IP addresses */
1093 if (tf.hosts != NULL && (host_list == NULL || tf.hosts_override))
1096 uschar *save_deliver_domain = deliver_domain;
1097 uschar *save_deliver_localpart = deliver_localpart;
1099 host_list = NULL; /* Ignore the router's hosts */
1101 deliver_domain = addr->domain;
1102 deliver_localpart = addr->local_part;
1103 s = expand_string(tf.hosts);
1104 deliver_domain = save_deliver_domain;
1105 deliver_localpart = save_deliver_localpart;
1109 log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand list of hosts "
1110 "\"%s\" in %s transport for callout: %s", tf.hosts,
1111 addr->transport->name, expand_string_message);
1115 uschar *canonical_name;
1116 host_item *host, *nexthost;
1117 host_build_hostlist(&host_list, s, tf.hosts_randomize);
1119 /* Just ignore failures to find a host address. If we don't manage
1120 to find any addresses, the callout will defer. Note that more than
1121 one address may be found for a single host, which will result in
1122 additional host items being inserted into the chain. Hence we must
1123 save the next host first. */
1125 for (host = host_list; host != NULL; host = nexthost)
1127 nexthost = host->next;
1128 if (tf.gethostbyname ||
1129 string_is_ip_address(host->name, NULL) != 0)
1130 (void)host_find_byname(host, NULL, &canonical_name, TRUE);
1133 int flags = HOST_FIND_BY_A;
1134 if (tf.qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
1135 if (tf.search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
1136 (void)host_find_bydns(host, NULL, flags, NULL, NULL, NULL,
1137 &canonical_name, NULL);
1144 /* Can only do a callout if we have at least one host! If the callout
1145 fails, it will have set ${sender,recipient}_verify_failure. */
1147 if (host_list != NULL)
1149 HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n");
1150 if (host_checking && !host_checking_callout)
1153 debug_printf("... callout omitted by default when host testing\n"
1154 "(Use -bhc if you want the callouts to happen.)\n");
1158 rc = do_callout(addr, host_list, &tf, callout, callout_overall,
1159 callout_connect, options, se_mailfrom, pm_mailfrom);
1164 HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor "
1165 "transport provided a host list\n");
1170 /* Otherwise, any failure is a routing failure */
1172 else *failure_ptr = US"route";
1174 /* A router may return REROUTED if it has set up a child address as a result
1175 of a change of domain name (typically from widening). In this case we always
1176 want to continue to verify the new child. */
1178 if (rc == REROUTED) continue;
1180 /* Handle hard failures */
1187 fprintf(f, "%s%s %s", ko_prefix, address,
1188 address_test_mode? "is undeliverable" : "failed to verify");
1189 if (!expn && admin_user)
1191 if (addr->basic_errno > 0)
1192 fprintf(f, ": %s", strerror(addr->basic_errno));
1193 if (addr->message != NULL)
1194 fprintf(f, ":\n %s", addr->message);
1196 fprintf(f, "%s\n", cr);
1199 if (!full_info) return copy_error(vaddr, addr, FAIL);
1205 else if (rc == DEFER)
1210 fprintf(f, "%s%s cannot be resolved at this time", ko_prefix, address);
1211 if (!expn && admin_user)
1213 if (addr->basic_errno > 0)
1214 fprintf(f, ":\n %s", strerror(addr->basic_errno));
1215 if (addr->message != NULL)
1216 fprintf(f, ":\n %s", addr->message);
1217 else if (addr->basic_errno <= 0)
1218 fprintf(f, ":\n unknown error");
1221 fprintf(f, "%s\n", cr);
1223 if (!full_info) return copy_error(vaddr, addr, DEFER);
1224 else if (yield == OK) yield = DEFER;
1227 /* If we are handling EXPN, we do not want to continue to route beyond
1232 uschar *ok_prefix = US"250-";
1233 if (addr_new == NULL)
1235 if (addr_local == NULL && addr_remote == NULL)
1236 fprintf(f, "250 mail to <%s> is discarded\r\n", address);
1238 fprintf(f, "250 <%s>\r\n", address);
1240 else while (addr_new != NULL)
1242 address_item *addr2 = addr_new;
1243 addr_new = addr2->next;
1244 if (addr_new == NULL) ok_prefix = US"250 ";
1245 fprintf(f, "%s<%s>\r\n", ok_prefix, addr2->address);
1250 /* Successful routing other than EXPN. */
1254 /* Handle successful routing when short info wanted. Otherwise continue for
1255 other (generated) addresses. Short info is the operational case. Full info
1256 can be requested only when debug_selector != 0 and a file is supplied.
1258 There is a conflict between the use of aliasing as an alternate email
1259 address, and as a sort of mailing list. If an alias turns the incoming
1260 address into just one address (e.g. J.Caesar->jc44) you may well want to
1261 carry on verifying the generated address to ensure it is valid when
1262 checking incoming mail. If aliasing generates multiple addresses, you
1263 probably don't want to do this. Exim therefore treats the generation of
1264 just a single new address as a special case, and continues on to verify the
1265 generated address. */
1267 if (!full_info && /* Stop if short info wanted AND */
1268 (((addr_new == NULL || /* No new address OR */
1269 addr_new->next != NULL || /* More than one new address OR */
1270 testflag(addr_new, af_pfr))) /* New address is pfr */
1272 (addr_new != NULL && /* At least one new address AND */
1273 success_on_redirect))) /* success_on_redirect is set */
1275 if (f != NULL) fprintf(f, "%s %s\n", address,
1276 address_test_mode? "is deliverable" : "verified");
1278 /* If we have carried on to verify a child address, we want the value
1279 of $address_data to be that of the child */
1281 vaddr->p.address_data = addr->p.address_data;
1285 } /* Loop for generated addresses */
1287 /* Display the full results of the successful routing, including any generated
1288 addresses. Control gets here only when full_info is set, which requires f not
1289 to be NULL, and this occurs only when a top-level verify is called with the
1290 debugging switch on.
1292 If there are no local and no remote addresses, and there were no pipes, files,
1293 or autoreplies, and there were no errors or deferments, the message is to be
1294 discarded, usually because of the use of :blackhole: in an alias file. */
1296 if (allok && addr_local == NULL && addr_remote == NULL)
1298 fprintf(f, "mail to %s is discarded\n", address);
1302 for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++)
1304 while (addr_list != NULL)
1306 address_item *addr = addr_list;
1307 address_item *p = addr->parent;
1308 addr_list = addr->next;
1310 fprintf(f, "%s", CS addr->address);
1311 #ifdef EXPERIMENTAL_SRS
1312 if(addr->p.srs_sender)
1313 fprintf(f, " [srs = %s]", addr->p.srs_sender);
1316 /* If the address is a duplicate, show something about it. */
1318 if (!testflag(addr, af_pfr))
1321 if ((tnode = tree_search(tree_duplicates, addr->unique)) != NULL)
1322 fprintf(f, " [duplicate, would not be delivered]");
1323 else tree_add_duplicate(addr->unique, addr);
1326 /* Now show its parents */
1330 fprintf(f, "\n <-- %s", p->address);
1335 /* Show router, and transport */
1337 fprintf(f, "router = %s, ", addr->router->name);
1338 fprintf(f, "transport = %s\n", (addr->transport == NULL)? US"unset" :
1339 addr->transport->name);
1341 /* Show any hosts that are set up by a router unless the transport
1342 is going to override them; fiddle a bit to get a nice format. */
1344 if (addr->host_list != NULL && addr->transport != NULL &&
1345 !addr->transport->overrides_hosts)
1350 for (h = addr->host_list; h != NULL; h = h->next)
1352 int len = Ustrlen(h->name);
1353 if (len > maxlen) maxlen = len;
1354 len = (h->address != NULL)? Ustrlen(h->address) : 7;
1355 if (len > maxaddlen) maxaddlen = len;
1357 for (h = addr->host_list; h != NULL; h = h->next)
1359 int len = Ustrlen(h->name);
1360 fprintf(f, " host %s ", h->name);
1361 while (len++ < maxlen) fprintf(f, " ");
1362 if (h->address != NULL)
1364 fprintf(f, "[%s] ", h->address);
1365 len = Ustrlen(h->address);
1367 else if (!addr->transport->info->local) /* Omit [unknown] for local */
1369 fprintf(f, "[unknown] ");
1373 while (len++ < maxaddlen) fprintf(f," ");
1374 if (h->mx >= 0) fprintf(f, "MX=%d", h->mx);
1375 if (h->port != PORT_NONE) fprintf(f, " port=%d", h->port);
1376 if (h->status == hstatus_unusable) fprintf(f, " ** unusable **");
1383 /* Will be DEFER or FAIL if any one address has, only for full_info (which is
1384 the -bv or -bt case). */
1392 /*************************************************
1393 * Check headers for syntax errors *
1394 *************************************************/
1396 /* This function checks those header lines that contain addresses, and verifies
1397 that all the addresses therein are syntactially correct.
1400 msgptr where to put an error message
1407 verify_check_headers(uschar **msgptr)
1412 for (h = header_list; h != NULL; h = h->next)
1414 if (h->type != htype_from &&
1415 h->type != htype_reply_to &&
1416 h->type != htype_sender &&
1417 h->type != htype_to &&
1418 h->type != htype_cc &&
1419 h->type != htype_bcc)
1422 colon = Ustrchr(h->text, ':');
1424 while (isspace(*s)) s++;
1426 parse_allow_group = TRUE; /* Allow group syntax */
1428 /* Loop for multiple addresses in the header */
1432 uschar *ss = parse_find_address_end(s, FALSE);
1433 uschar *recipient, *errmess;
1434 int terminator = *ss;
1435 int start, end, domain;
1437 /* Temporarily terminate the string at this point, and extract the
1438 operative address within. */
1441 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
1444 /* Permit an unqualified address only if the message is local, or if the
1445 sending host is configured to be permitted to send them. */
1447 if (recipient != NULL && domain == 0)
1449 if (h->type == htype_from || h->type == htype_sender)
1451 if (!allow_unqualified_sender) recipient = NULL;
1455 if (!allow_unqualified_recipient) recipient = NULL;
1457 if (recipient == NULL) errmess = US"unqualified address not permitted";
1460 /* It's an error if no address could be extracted, except for the special
1461 case of an empty address. */
1463 if (recipient == NULL && Ustrcmp(errmess, "empty address") != 0)
1465 uschar *verb = US"is";
1470 /* Arrange not to include any white space at the end in the
1471 error message or the header name. */
1473 while (t > s && isspace(t[-1])) t--;
1474 while (tt > h->text && isspace(tt[-1])) tt--;
1476 /* Add the address that failed to the error message, since in a
1477 header with very many addresses it is sometimes hard to spot
1478 which one is at fault. However, limit the amount of address to
1479 quote - cases have been seen where, for example, a missing double
1480 quote in a humungous To: header creates an "address" that is longer
1481 than string_sprintf can handle. */
1490 *msgptr = string_printing(
1491 string_sprintf("%s: failing address in \"%.*s:\" header %s: %.*s",
1492 errmess, tt - h->text, h->text, verb, len, s));
1497 /* Advance to the next address */
1499 s = ss + (terminator? 1:0);
1500 while (isspace(*s)) s++;
1501 } /* Next address */
1509 /*************************************************
1510 * Check for blind recipients *
1511 *************************************************/
1513 /* This function checks that every (envelope) recipient is mentioned in either
1514 the To: or Cc: header lines, thus detecting blind carbon copies.
1516 There are two ways of scanning that could be used: either scan the header lines
1517 and tick off the recipients, or scan the recipients and check the header lines.
1518 The original proposed patch did the former, but I have chosen to do the latter,
1519 because (a) it requires no memory and (b) will use fewer resources when there
1520 are many addresses in To: and/or Cc: and only one or two envelope recipients.
1523 Returns: OK if there are no blind recipients
1524 FAIL if there is at least one blind recipient
1528 verify_check_notblind(void)
1531 for (i = 0; i < recipients_count; i++)
1535 uschar *address = recipients_list[i].address;
1537 for (h = header_list; !found && h != NULL; h = h->next)
1541 if (h->type != htype_to && h->type != htype_cc) continue;
1543 colon = Ustrchr(h->text, ':');
1545 while (isspace(*s)) s++;
1547 parse_allow_group = TRUE; /* Allow group syntax */
1549 /* Loop for multiple addresses in the header */
1553 uschar *ss = parse_find_address_end(s, FALSE);
1554 uschar *recipient,*errmess;
1555 int terminator = *ss;
1556 int start, end, domain;
1558 /* Temporarily terminate the string at this point, and extract the
1559 operative address within. */
1562 recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE);
1565 /* If we found a valid recipient that has a domain, compare it with the
1566 envelope recipient. Local parts are compared case-sensitively, domains
1567 case-insensitively. By comparing from the start with length "domain", we
1568 include the "@" at the end, which ensures that we are comparing the whole
1569 local part of each address. */
1571 if (recipient != NULL && domain != 0)
1573 found = Ustrncmp(recipient, address, domain) == 0 &&
1574 strcmpic(recipient + domain, address + domain) == 0;
1578 /* Advance to the next address */
1580 s = ss + (terminator? 1:0);
1581 while (isspace(*s)) s++;
1582 } /* Next address */
1583 } /* Next header (if found is false) */
1585 if (!found) return FAIL;
1586 } /* Next recipient */
1593 /*************************************************
1594 * Find if verified sender *
1595 *************************************************/
1597 /* Usually, just a single address is verified as the sender of the message.
1598 However, Exim can be made to verify other addresses as well (often related in
1599 some way), and this is useful in some environments. There may therefore be a
1600 chain of such addresses that have previously been tested. This function finds
1601 whether a given address is on the chain.
1603 Arguments: the address to be verified
1604 Returns: pointer to an address item, or NULL
1608 verify_checked_sender(uschar *sender)
1611 for (addr = sender_verified_list; addr != NULL; addr = addr->next)
1612 if (Ustrcmp(sender, addr->address) == 0) break;
1620 /*************************************************
1621 * Get valid header address *
1622 *************************************************/
1624 /* Scan the originator headers of the message, looking for an address that
1625 verifies successfully. RFC 822 says:
1627 o The "Sender" field mailbox should be sent notices of
1628 any problems in transport or delivery of the original
1629 messages. If there is no "Sender" field, then the
1630 "From" field mailbox should be used.
1632 o If the "Reply-To" field exists, then the reply should
1633 go to the addresses indicated in that field and not to
1634 the address(es) indicated in the "From" field.
1636 So we check a Sender field if there is one, else a Reply_to field, else a From
1637 field. As some strange messages may have more than one of these fields,
1638 especially if they are resent- fields, check all of them if there is more than
1642 user_msgptr points to where to put a user error message
1643 log_msgptr points to where to put a log error message
1644 callout timeout for callout check (passed to verify_address())
1645 callout_overall overall callout timeout (ditto)
1646 callout_connect connect callout timeout (ditto)
1647 se_mailfrom mailfrom for verify; NULL => ""
1648 pm_mailfrom sender for pm callout check (passed to verify_address())
1649 options callout options (passed to verify_address())
1650 verrno where to put the address basic_errno
1652 If log_msgptr is set to something without setting user_msgptr, the caller
1653 normally uses log_msgptr for both things.
1655 Returns: result of the verification attempt: OK, FAIL, or DEFER;
1656 FAIL is given if no appropriate headers are found
1660 verify_check_header_address(uschar **user_msgptr, uschar **log_msgptr,
1661 int callout, int callout_overall, int callout_connect, uschar *se_mailfrom,
1662 uschar *pm_mailfrom, int options, int *verrno)
1664 static int header_types[] = { htype_sender, htype_reply_to, htype_from };
1668 for (i = 0; i < 3; i++)
1671 for (h = header_list; h != NULL; h = h->next)
1673 int terminator, new_ok;
1674 uschar *s, *ss, *endname;
1676 if (h->type != header_types[i]) continue;
1677 s = endname = Ustrchr(h->text, ':') + 1;
1681 address_item *vaddr;
1683 while (isspace(*s) || *s == ',') s++;
1684 if (*s == 0) break; /* End of header */
1686 ss = parse_find_address_end(s, FALSE);
1688 /* The terminator is a comma or end of header, but there may be white
1689 space preceding it (including newline for the last address). Move back
1690 past any white space so we can check against any cached envelope sender
1691 address verifications. */
1693 while (isspace(ss[-1])) ss--;
1697 HDEBUG(D_verify) debug_printf("verifying %.*s header address %s\n",
1698 (int)(endname - h->text), h->text, s);
1700 /* See if we have already verified this address as an envelope sender,
1701 and if so, use the previous answer. */
1703 vaddr = verify_checked_sender(s);
1705 if (vaddr != NULL && /* Previously checked */
1706 (callout <= 0 || /* No callout needed; OR */
1707 vaddr->special_action > 256)) /* Callout was done */
1709 new_ok = vaddr->special_action & 255;
1710 HDEBUG(D_verify) debug_printf("previously checked as envelope sender\n");
1711 *ss = terminator; /* Restore shortened string */
1714 /* Otherwise we run the verification now. We must restore the shortened
1715 string before running the verification, so the headers are correct, in
1716 case there is any rewriting. */
1720 int start, end, domain;
1721 uschar *address = parse_extract_address(s, log_msgptr, &start,
1722 &end, &domain, FALSE);
1726 /* If verification failed because of a syntax error, fail this
1727 function, and ensure that the failing address gets added to the error
1730 if (address == NULL)
1733 if (*log_msgptr != NULL)
1735 while (ss > s && isspace(ss[-1])) ss--;
1736 *log_msgptr = string_sprintf("syntax error in '%.*s' header when "
1737 "scanning for sender: %s in \"%.*s\"",
1738 endname - h->text, h->text, *log_msgptr, ss - s, s);
1743 /* Else go ahead with the sender verification. But it isn't *the*
1744 sender of the message, so set vopt_fake_sender to stop sender_address
1745 being replaced after rewriting or qualification. */
1749 vaddr = deliver_make_addr(address, FALSE);
1750 new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender,
1751 callout, callout_overall, callout_connect, se_mailfrom,
1756 /* We now have the result, either newly found, or cached. If we are
1757 giving out error details, set a specific user error. This means that the
1758 last of these will be returned to the user if all three fail. We do not
1759 set a log message - the generic one below will be used. */
1763 *verrno = vaddr->basic_errno;
1764 if (smtp_return_error_details)
1766 *user_msgptr = string_sprintf("Rejected after DATA: "
1767 "could not verify \"%.*s\" header address\n%s: %s",
1768 endname - h->text, h->text, vaddr->address, vaddr->message);
1772 /* Success or defer */
1774 if (new_ok == OK) return OK;
1775 if (new_ok == DEFER) yield = DEFER;
1777 /* Move on to any more addresses in the header */
1784 if (yield == FAIL && *log_msgptr == NULL)
1785 *log_msgptr = US"there is no valid sender in any header line";
1787 if (yield == DEFER && *log_msgptr == NULL)
1788 *log_msgptr = US"all attempts to verify a sender in a header line deferred";
1796 /*************************************************
1797 * Get RFC 1413 identification *
1798 *************************************************/
1800 /* Attempt to get an id from the sending machine via the RFC 1413 protocol. If
1801 the timeout is set to zero, then the query is not done. There may also be lists
1802 of hosts and nets which are exempt. To guard against malefactors sending
1803 non-printing characters which could, for example, disrupt a message's headers,
1804 make sure the string consists of printing characters only.
1807 port the port to connect to; usually this is IDENT_PORT (113), but when
1808 running in the test harness with -bh a different value is used.
1812 Side effect: any received ident value is put in sender_ident (NULL otherwise)
1816 verify_get_ident(int port)
1818 int sock, host_af, qlen;
1819 int received_sender_port, received_interface_port, n;
1821 uschar buffer[2048];
1823 /* Default is no ident. Check whether we want to do an ident check for this
1826 sender_ident = NULL;
1827 if (rfc1413_query_timeout <= 0 || verify_check_host(&rfc1413_hosts) != OK)
1830 DEBUG(D_ident) debug_printf("doing ident callback\n");
1832 /* Set up a connection to the ident port of the remote host. Bind the local end
1833 to the incoming interface address. If the sender host address is an IPv6
1834 address, the incoming interface address will also be IPv6. */
1836 host_af = (Ustrchr(sender_host_address, ':') == NULL)? AF_INET : AF_INET6;
1837 sock = ip_socket(SOCK_STREAM, host_af);
1838 if (sock < 0) return;
1840 if (ip_bind(sock, host_af, interface_address, 0) < 0)
1842 DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n",
1847 if (ip_connect(sock, host_af, sender_host_address, port, rfc1413_query_timeout)
1850 if (errno == ETIMEDOUT && (log_extra_selector & LX_ident_timeout) != 0)
1852 log_write(0, LOG_MAIN, "ident connection to %s timed out",
1853 sender_host_address);
1857 DEBUG(D_ident) debug_printf("ident connection to %s failed: %s\n",
1858 sender_host_address, strerror(errno));
1863 /* Construct and send the query. */
1865 sprintf(CS buffer, "%d , %d\r\n", sender_host_port, interface_port);
1866 qlen = Ustrlen(buffer);
1867 if (send(sock, buffer, qlen, 0) < 0)
1869 DEBUG(D_ident) debug_printf("ident send failed: %s\n", strerror(errno));
1873 /* Read a response line. We put it into the rest of the buffer, using several
1874 recv() calls if necessary. */
1882 int size = sizeof(buffer) - (p - buffer);
1884 if (size <= 0) goto END_OFF; /* Buffer filled without seeing \n. */
1885 count = ip_recv(sock, p, size, rfc1413_query_timeout);
1886 if (count <= 0) goto END_OFF; /* Read error or EOF */
1888 /* Scan what we just read, to see if we have reached the terminating \r\n. Be
1889 generous, and accept a plain \n terminator as well. The only illegal
1892 for (pp = p; pp < p + count; pp++)
1894 if (*pp == 0) goto END_OFF; /* Zero octet not allowed */
1897 if (pp[-1] == '\r') pp--;
1899 goto GOT_DATA; /* Break out of both loops */
1903 /* Reached the end of the data without finding \n. Let the loop continue to
1904 read some more, if there is room. */
1911 /* We have received a line of data. Check it carefully. It must start with the
1912 same two port numbers that we sent, followed by data as defined by the RFC. For
1915 12345 , 25 : USERID : UNIX :root
1917 However, the amount of white space may be different to what we sent. In the
1918 "osname" field there may be several sub-fields, comma separated. The data we
1919 actually want to save follows the third colon. Some systems put leading spaces
1920 in it - we discard those. */
1922 if (sscanf(CS buffer + qlen, "%d , %d%n", &received_sender_port,
1923 &received_interface_port, &n) != 2 ||
1924 received_sender_port != sender_host_port ||
1925 received_interface_port != interface_port)
1928 p = buffer + qlen + n;
1929 while(isspace(*p)) p++;
1930 if (*p++ != ':') goto END_OFF;
1931 while(isspace(*p)) p++;
1932 if (Ustrncmp(p, "USERID", 6) != 0) goto END_OFF;
1934 while(isspace(*p)) p++;
1935 if (*p++ != ':') goto END_OFF;
1936 while (*p != 0 && *p != ':') p++;
1937 if (*p++ == 0) goto END_OFF;
1938 while(isspace(*p)) p++;
1939 if (*p == 0) goto END_OFF;
1941 /* The rest of the line is the data we want. We turn it into printing
1942 characters when we save it, so that it cannot mess up the format of any logging
1943 or Received: lines into which it gets inserted. We keep a maximum of 127
1946 sender_ident = string_printing(string_copyn(p, 127));
1947 DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident);
1957 /*************************************************
1958 * Match host to a single host-list item *
1959 *************************************************/
1961 /* This function compares a host (name or address) against a single item
1962 from a host list. The host name gets looked up if it is needed and is not
1963 already known. The function is called from verify_check_this_host() via
1964 match_check_list(), which is why most of its arguments are in a single block.
1967 arg the argument block (see below)
1968 ss the host-list item
1969 valueptr where to pass back looked up data, or NULL
1970 error for error message when returning ERROR
1973 host_name (a) the host name, or
1974 (b) NULL, implying use sender_host_name and
1975 sender_host_aliases, looking them up if required, or
1976 (c) the empty string, meaning that only IP address matches
1978 host_address the host address
1979 host_ipv4 the IPv4 address taken from an IPv6 one
1983 DEFER lookup deferred
1984 ERROR (a) failed to find the host name or IP address, or
1985 (b) unknown lookup type specified, or
1986 (c) host name encountered when only IP addresses are
1991 check_host(void *arg, uschar *ss, uschar **valueptr, uschar **error)
1993 check_host_block *cb = (check_host_block *)arg;
1996 BOOL iplookup = FALSE;
1997 BOOL isquery = FALSE;
1998 BOOL isiponly = cb->host_name != NULL && cb->host_name[0] == 0;
2003 /* Optimize for the special case when the pattern is "*". */
2005 if (*ss == '*' && ss[1] == 0) return OK;
2007 /* If the pattern is empty, it matches only in the case when there is no host -
2008 this can occur in ACL checking for SMTP input using the -bs option. In this
2009 situation, the host address is the empty string. */
2011 if (cb->host_address[0] == 0) return (*ss == 0)? OK : FAIL;
2012 if (*ss == 0) return FAIL;
2014 /* If the pattern is precisely "@" then match against the primary host name,
2015 provided that host name matching is permitted; if it's "@[]" match against the
2016 local host's IP addresses. */
2022 if (isiponly) return ERROR;
2023 ss = primary_hostname;
2025 else if (Ustrcmp(ss, "@[]") == 0)
2027 ip_address_item *ip;
2028 for (ip = host_find_interfaces(); ip != NULL; ip = ip->next)
2029 if (Ustrcmp(ip->address, cb->host_address) == 0) return OK;
2034 /* If the pattern is an IP address, optionally followed by a bitmask count, do
2035 a (possibly masked) comparision with the current IP address. */
2037 if (string_is_ip_address(ss, &maskoffset) != 0)
2038 return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL);
2040 /* The pattern is not an IP address. A common error that people make is to omit
2041 one component of an IPv4 address, either by accident, or believing that, for
2042 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,
2043 which it isn't. (Those applications that do accept 1.2.3 as an IP address
2044 interpret it as 1.2.0.3 because the final component becomes 16-bit - this is an
2045 ancient specification.) To aid in debugging these cases, we give a specific
2046 error if the pattern contains only digits and dots or contains a slash preceded
2047 only by digits and dots (a slash at the start indicates a file name and of
2048 course slashes may be present in lookups, but not preceded only by digits and
2051 for (t = ss; isdigit(*t) || *t == '.'; t++);
2052 if (*t == 0 || (*t == '/' && t != ss))
2054 *error = US"malformed IPv4 address or address mask";
2058 /* See if there is a semicolon in the pattern */
2060 semicolon = Ustrchr(ss, ';');
2062 /* If we are doing an IP address only match, then all lookups must be IP
2063 address lookups, even if there is no "net-". */
2067 iplookup = semicolon != NULL;
2070 /* Otherwise, if the item is of the form net[n]-lookup;<file|query> then it is
2071 a lookup on a masked IP network, in textual form. We obey this code even if we
2072 have already set iplookup, so as to skip over the "net-" prefix and to set the
2073 mask length. The net- stuff really only applies to single-key lookups where the
2074 key is implicit. For query-style lookups the key is specified in the query.
2075 From release 4.30, the use of net- for query style is no longer needed, but we
2076 retain it for backward compatibility. */
2078 if (Ustrncmp(ss, "net", 3) == 0 && semicolon != NULL)
2081 for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0';
2082 if (mlen == 0 && t == ss+3) mlen = -1; /* No mask supplied */
2083 iplookup = (*t++ == '-');
2087 /* Do the IP address lookup if that is indeed what we have */
2095 uschar *filename, *key, *result;
2098 /* Find the search type */
2100 search_type = search_findtype(t, semicolon - t);
2102 if (search_type < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
2103 search_error_message);
2105 /* Adjust parameters for the type of lookup. For a query-style lookup, there
2106 is no file name, and the "key" is just the query. For query-style with a file
2107 name, we have to fish the file off the start of the query. For a single-key
2108 lookup, the key is the current IP address, masked appropriately, and
2109 reconverted to text form, with the mask appended. For IPv6 addresses, specify
2110 dot separators instead of colons. */
2112 if (mac_islookup(search_type, lookup_absfilequery))
2114 filename = semicolon + 1;
2116 while (*key != 0 && !isspace(*key)) key++;
2117 filename = string_copyn(filename, key - filename);
2118 while (isspace(*key)) key++;
2120 else if (mac_islookup(search_type, lookup_querystyle))
2123 key = semicolon + 1;
2127 insize = host_aton(cb->host_address, incoming);
2128 host_mask(insize, incoming, mlen);
2129 (void)host_nmtoa(insize, incoming, mlen, buffer, '.');
2131 filename = semicolon + 1;
2134 /* Now do the actual lookup; note that there is no search_close() because
2135 of the caching arrangements. */
2137 handle = search_open(filename, search_type, 0, NULL, NULL);
2138 if (handle == NULL) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s",
2139 search_error_message);
2140 result = search_find(handle, filename, key, -1, NULL, 0, 0, NULL);
2141 if (valueptr != NULL) *valueptr = result;
2142 return (result != NULL)? OK : search_find_defer? DEFER: FAIL;
2145 /* The pattern is not an IP address or network reference of any kind. That is,
2146 it is a host name pattern. If this is an IP only match, there's an error in the
2151 *error = US"cannot match host name in match_ip list";
2155 /* Check the characters of the pattern to see if they comprise only letters,
2156 digits, full stops, and hyphens (the constituents of domain names). Allow
2157 underscores, as they are all too commonly found. Sigh. Also, if
2158 allow_utf8_domains is set, allow top-bit characters. */
2160 for (t = ss; *t != 0; t++)
2161 if (!isalnum(*t) && *t != '.' && *t != '-' && *t != '_' &&
2162 (!allow_utf8_domains || *t < 128)) break;
2164 /* If the pattern is a complete domain name, with no fancy characters, look up
2165 its IP address and match against that. Note that a multi-homed host will add
2166 items to the chain. */
2177 rc = host_find_byname(&h, NULL, NULL, FALSE);
2178 if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
2181 for (hh = &h; hh != NULL; hh = hh->next)
2183 if (host_is_in_net(hh->address, cb->host_address, 0)) return OK;
2187 if (rc == HOST_FIND_AGAIN) return DEFER;
2188 *error = string_sprintf("failed to find IP address for %s", ss);
2192 /* Almost all subsequent comparisons require the host name, and can be done
2193 using the general string matching function. When this function is called for
2194 outgoing hosts, the name is always given explicitly. If it is NULL, it means we
2195 must use sender_host_name and its aliases, looking them up if necessary. */
2197 if (cb->host_name != NULL) /* Explicit host name given */
2198 return match_check_string(cb->host_name, ss, -1, TRUE, TRUE, TRUE,
2201 /* Host name not given; in principle we need the sender host name and its
2202 aliases. However, for query-style lookups, we do not need the name if the
2203 query does not contain $sender_host_name. From release 4.23, a reference to
2204 $sender_host_name causes it to be looked up, so we don't need to do the lookup
2207 if ((semicolon = Ustrchr(ss, ';')) != NULL)
2210 int partial, affixlen, starflags, id;
2213 id = search_findtype_partial(ss, &partial, &affix, &affixlen, &starflags);
2216 if (id < 0) /* Unknown lookup type */
2218 log_write(0, LOG_MAIN|LOG_PANIC, "%s in host list item \"%s\"",
2219 search_error_message, ss);
2222 isquery = mac_islookup(id, lookup_querystyle|lookup_absfilequery);
2227 switch(match_check_string(US"", ss, -1, TRUE, TRUE, TRUE, valueptr))
2230 case DEFER: return DEFER;
2231 default: return FAIL;
2235 /* Not a query-style lookup; must ensure the host name is present, and then we
2236 do a check on the name and all its aliases. */
2238 if (sender_host_name == NULL)
2240 HDEBUG(D_host_lookup)
2241 debug_printf("sender host name required, to match against %s\n", ss);
2242 if (host_lookup_failed || host_name_lookup() != OK)
2244 *error = string_sprintf("failed to find host name for %s",
2245 sender_host_address);;
2248 host_build_sender_fullhost();
2251 /* Match on the sender host name, using the general matching function */
2253 switch(match_check_string(sender_host_name, ss, -1, TRUE, TRUE, TRUE,
2257 case DEFER: return DEFER;
2260 /* If there are aliases, try matching on them. */
2262 aliases = sender_host_aliases;
2263 while (*aliases != NULL)
2265 switch(match_check_string(*aliases++, ss, -1, TRUE, TRUE, TRUE, valueptr))
2268 case DEFER: return DEFER;
2277 /*************************************************
2278 * Check a specific host matches a host list *
2279 *************************************************/
2281 /* This function is passed a host list containing items in a number of
2282 different formats and the identity of a host. Its job is to determine whether
2283 the given host is in the set of hosts defined by the list. The host name is
2284 passed as a pointer so that it can be looked up if needed and not already
2285 known. This is commonly the case when called from verify_check_host() to check
2286 an incoming connection. When called from elsewhere the host name should usually
2289 This function is now just a front end to match_check_list(), which runs common
2290 code for scanning a list. We pass it the check_host() function to perform a
2294 listptr pointer to the host list
2295 cache_bits pointer to cache for named lists, or NULL
2296 host_name the host name or NULL, implying use sender_host_name and
2297 sender_host_aliases, looking them up if required
2298 host_address the IP address
2299 valueptr if not NULL, data from a lookup is passed back here
2301 Returns: OK if the host is in the defined set
2302 FAIL if the host is not in the defined set,
2303 DEFER if a data lookup deferred (not a host lookup)
2305 If the host name was needed in order to make a comparison, and could not be
2306 determined from the IP address, the result is FAIL unless the item
2307 "+allow_unknown" was met earlier in the list, in which case OK is returned. */
2310 verify_check_this_host(uschar **listptr, unsigned int *cache_bits,
2311 uschar *host_name, uschar *host_address, uschar **valueptr)
2314 unsigned int *local_cache_bits = cache_bits;
2315 uschar *save_host_address = deliver_host_address;
2316 check_host_block cb;
2317 cb.host_name = host_name;
2318 cb.host_address = host_address;
2320 if (valueptr != NULL) *valueptr = NULL;
2322 /* If the host address starts off ::ffff: it is an IPv6 address in
2323 IPv4-compatible mode. Find the IPv4 part for checking against IPv4
2326 cb.host_ipv4 = (Ustrncmp(host_address, "::ffff:", 7) == 0)?
2327 host_address + 7 : host_address;
2329 /* During the running of the check, put the IP address into $host_address. In
2330 the case of calls from the smtp transport, it will already be there. However,
2331 in other calls (e.g. when testing ignore_target_hosts), it won't. Just to be on
2332 the safe side, any existing setting is preserved, though as I write this
2333 (November 2004) I can't see any cases where it is actually needed. */
2335 deliver_host_address = host_address;
2336 rc = match_check_list(
2337 listptr, /* the list */
2338 0, /* separator character */
2339 &hostlist_anchor, /* anchor pointer */
2340 &local_cache_bits, /* cache pointer */
2341 check_host, /* function for testing */
2342 &cb, /* argument for function */
2343 MCL_HOST, /* type of check */
2344 (host_address == sender_host_address)?
2345 US"host" : host_address, /* text for debugging */
2346 valueptr); /* where to pass back data */
2347 deliver_host_address = save_host_address;
2354 /*************************************************
2355 * Check the remote host matches a list *
2356 *************************************************/
2358 /* This is a front end to verify_check_this_host(), created because checking
2359 the remote host is a common occurrence. With luck, a good compiler will spot
2360 the tail recursion and optimize it. If there's no host address, this is
2361 command-line SMTP input - check against an empty string for the address.
2364 listptr pointer to the host list
2366 Returns: the yield of verify_check_this_host(),
2367 i.e. OK, FAIL, or DEFER
2371 verify_check_host(uschar **listptr)
2373 return verify_check_this_host(listptr, sender_host_cache, NULL,
2374 (sender_host_address == NULL)? US"" : sender_host_address, NULL);
2381 /*************************************************
2382 * Invert an IP address for a DNS black list *
2383 *************************************************/
2387 buffer where to put the answer
2388 address the address to invert
2392 invert_address(uschar *buffer, uschar *address)
2395 uschar *bptr = buffer;
2397 /* If this is an IPv4 address mapped into IPv6 format, adjust the pointer
2398 to the IPv4 part only. */
2400 if (Ustrncmp(address, "::ffff:", 7) == 0) address += 7;
2402 /* Handle IPv4 address: when HAVE_IPV6 is false, the result of host_aton() is
2405 if (host_aton(address, bin) == 1)
2409 for (i = 0; i < 4; i++)
2411 sprintf(CS bptr, "%d.", x & 255);
2412 while (*bptr) bptr++;
2417 /* Handle IPv6 address. Actually, as far as I know, there are no IPv6 addresses
2418 in any DNS black lists, and the format in which they will be looked up is
2419 unknown. This is just a guess. */
2425 for (j = 3; j >= 0; j--)
2428 for (i = 0; i < 8; i++)
2430 sprintf(CS bptr, "%x.", x & 15);
2431 while (*bptr) bptr++;
2441 /*************************************************
2442 * Perform a single dnsbl lookup *
2443 *************************************************/
2445 /* This function is called from verify_check_dnsbl() below.
2448 domain the outer dnsbl domain (for debug message)
2449 keydomain the current keydomain (for debug message)
2450 query the domain to be looked up
2451 iplist the list of matching IP addresses
2452 bitmask true if bitmask matching is wanted
2453 invert_result true if result to be inverted
2454 defer_return what to return for a defer
2456 Returns: OK if lookup succeeded
2461 one_check_dnsbl(uschar *domain, uschar *keydomain, uschar *query,
2462 uschar *iplist, BOOL bitmask, BOOL invert_result, int defer_return)
2467 dnsbl_cache_block *cb;
2468 int old_pool = store_pool;
2470 /* Look for this query in the cache. */
2472 t = tree_search(dnsbl_cache, query);
2474 /* If not cached from a previous lookup, we must do a DNS lookup, and
2475 cache the result in permanent memory. */
2479 store_pool = POOL_PERM;
2481 /* Set up a tree entry to cache the lookup */
2483 t = store_get(sizeof(tree_node) + Ustrlen(query));
2484 Ustrcpy(t->name, query);
2485 t->data.ptr = cb = store_get(sizeof(dnsbl_cache_block));
2486 (void)tree_insertnode(&dnsbl_cache, t);
2488 /* Do the DNS loopup . */
2490 HDEBUG(D_dnsbl) debug_printf("new DNS lookup for %s\n", query);
2491 cb->rc = dns_basic_lookup(&dnsa, query, T_A);
2492 cb->text_set = FALSE;
2496 /* If the lookup succeeded, cache the RHS address. The code allows for
2497 more than one address - this was for complete generality and the possible
2498 use of A6 records. However, A6 records have been reduced to experimental
2499 status (August 2001) and may die out. So they may never get used at all,
2500 let alone in dnsbl records. However, leave the code here, just in case.
2502 Quite apart from one A6 RR generating multiple addresses, there are DNS
2503 lists that return more than one A record, so we must handle multiple
2504 addresses generated in that way as well. */
2506 if (cb->rc == DNS_SUCCEED)
2509 dns_address **addrp = &(cb->rhs);
2510 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2512 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
2514 if (rr->type == T_A)
2516 dns_address *da = dns_address_from_rr(&dnsa, rr);
2520 while (da->next != NULL) da = da->next;
2521 addrp = &(da->next);
2526 /* If we didn't find any A records, change the return code. This can
2527 happen when there is a CNAME record but there are no A records for what
2530 if (cb->rhs == NULL) cb->rc = DNS_NODATA;
2533 store_pool = old_pool;
2536 /* Previous lookup was cached */
2540 HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
2544 /* We now have the result of the DNS lookup, either newly done, or cached
2545 from a previous call. If the lookup succeeded, check against the address
2546 list if there is one. This may be a positive equality list (introduced by
2547 "="), a negative equality list (introduced by "!="), a positive bitmask
2548 list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/
2550 if (cb->rc == DNS_SUCCEED)
2552 dns_address *da = NULL;
2553 uschar *addlist = cb->rhs->address;
2555 /* For A and AAAA records, there may be multiple addresses from multiple
2556 records. For A6 records (currently not expected to be used) there may be
2557 multiple addresses from a single record. */
2559 for (da = cb->rhs->next; da != NULL; da = da->next)
2560 addlist = string_sprintf("%s, %s", addlist, da->address);
2562 HDEBUG(D_dnsbl) debug_printf("DNS lookup for %s succeeded (yielding %s)\n",
2565 /* Address list check; this can be either for equality, or via a bitmask.
2566 In the latter case, all the bits must match. */
2572 uschar *ptr = iplist;
2574 while (string_nextinlist(&ptr, &ipsep, ip, sizeof(ip)) != NULL)
2576 /* Handle exact matching */
2579 for (da = cb->rhs; da != NULL; da = da->next)
2581 if (Ustrcmp(CS da->address, ip) == 0) break;
2584 /* Handle bitmask matching */
2590 /* At present, all known DNS blocking lists use A records, with
2591 IPv4 addresses on the RHS encoding the information they return. I
2592 wonder if this will linger on as the last vestige of IPv4 when IPv6
2593 is ubiquitous? Anyway, for now we use paranoia code to completely
2594 ignore IPv6 addresses. The default mask is 0, which always matches.
2595 We change this only for IPv4 addresses in the list. */
2597 if (host_aton(ip, address) == 1) mask = address[0];
2599 /* Scan the returned addresses, skipping any that are IPv6 */
2601 for (da = cb->rhs; da != NULL; da = da->next)
2603 if (host_aton(da->address, address) != 1) continue;
2604 if ((address[0] & mask) == mask) break;
2608 /* Break out if a match has been found */
2610 if (da != NULL) break;
2615 (a) No IP address in a positive list matched, or
2616 (b) An IP address in a negative list did match
2618 then behave as if the DNSBL lookup had not succeeded, i.e. the host is
2621 if (invert_result != (da == NULL))
2625 debug_printf("=> but we are not accepting this block class because\n");
2626 debug_printf("=> there was %s match for %c%s\n",
2627 invert_result? "an exclude":"no", bitmask? '&' : '=', iplist);
2633 /* Either there was no IP list, or the record matched. Look up a TXT record
2634 if it hasn't previously been done. */
2638 cb->text_set = TRUE;
2639 if (dns_basic_lookup(&dnsa, query, T_TXT) == DNS_SUCCEED)
2642 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2644 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
2645 if (rr->type == T_TXT) break;
2648 int len = (rr->data)[0];
2649 if (len > 511) len = 127;
2650 store_pool = POOL_PERM;
2651 cb->text = string_sprintf("%.*s", len, (const uschar *)(rr->data+1));
2652 store_pool = old_pool;
2657 dnslist_value = addlist;
2658 dnslist_text = cb->text;
2662 /* There was a problem with the DNS lookup */
2664 if (cb->rc != DNS_NOMATCH && cb->rc != DNS_NODATA)
2666 log_write(L_dnslist_defer, LOG_MAIN,
2667 "DNS list lookup defer (probably timeout) for %s: %s", query,
2668 (defer_return == OK)? US"assumed in list" :
2669 (defer_return == FAIL)? US"assumed not in list" :
2670 US"returned DEFER");
2671 return defer_return;
2674 /* No entry was found in the DNS; continue for next domain */
2678 debug_printf("DNS lookup for %s failed\n", query);
2679 debug_printf("=> that means %s is not listed at %s\n",
2689 /*************************************************
2690 * Check host against DNS black lists *
2691 *************************************************/
2693 /* This function runs checks against a list of DNS black lists, until one
2694 matches. Each item on the list can be of the form
2696 domain=ip-address/key
2698 The domain is the right-most domain that is used for the query, for example,
2699 blackholes.mail-abuse.org. If the IP address is present, there is a match only
2700 if the DNS lookup returns a matching IP address. Several addresses may be
2701 given, comma-separated, for example: x.y.z=127.0.0.1,127.0.0.2.
2703 If no key is given, what is looked up in the domain is the inverted IP address
2704 of the current client host. If a key is given, it is used to construct the
2705 domain for the lookup. For example,
2707 dsn.rfc-ignorant.org/$sender_address_domain
2709 After finding a match in the DNS, the domain is placed in $dnslist_domain, and
2710 then we check for a TXT record for an error message, and if found, save its
2711 value in $dnslist_text. We also cache everything in a tree, to optimize
2714 Note: an address for testing RBL is 192.203.178.39
2715 Note: an address for testing DUL is 192.203.178.4
2716 Note: a domain for testing RFCI is example.tld.dsn.rfc-ignorant.org
2719 listptr the domain/address/data list
2721 Returns: OK successful lookup (i.e. the address is on the list), or
2722 lookup deferred after +include_unknown
2723 FAIL name not found, or no data found for the given type, or
2724 lookup deferred after +exclude_unknown (default)
2725 DEFER lookup failure, if +defer_unknown was set
2729 verify_check_dnsbl(uschar **listptr)
2732 int defer_return = FAIL;
2733 BOOL invert_result = FALSE;
2734 uschar *list = *listptr;
2737 uschar buffer[1024];
2738 uschar query[256]; /* DNS domain max length */
2739 uschar revadd[128]; /* Long enough for IPv6 address */
2741 /* Indicate that the inverted IP address is not yet set up */
2745 /* In case this is the first time the DNS resolver is being used. */
2747 dns_init(FALSE, FALSE);
2749 /* Loop through all the domains supplied, until something matches */
2751 while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
2755 BOOL bitmask = FALSE;
2759 HDEBUG(D_dnsbl) debug_printf("DNS list check: %s\n", domain);
2761 /* Deal with special values that change the behaviour on defer */
2763 if (domain[0] == '+')
2765 if (strcmpic(domain, US"+include_unknown") == 0) defer_return = OK;
2766 else if (strcmpic(domain, US"+exclude_unknown") == 0) defer_return = FAIL;
2767 else if (strcmpic(domain, US"+defer_unknown") == 0) defer_return = DEFER;
2769 log_write(0, LOG_MAIN|LOG_PANIC, "unknown item in dnslist (ignored): %s",
2774 /* See if there's explicit data to be looked up */
2776 key = Ustrchr(domain, '/');
2777 if (key != NULL) *key++ = 0;
2779 /* See if there's a list of addresses supplied after the domain name. This is
2780 introduced by an = or a & character; if preceded by ! we invert the result.
2783 iplist = Ustrchr(domain, '=');
2787 iplist = Ustrchr(domain, '&');
2792 if (iplist > domain && iplist[-1] == '!')
2794 invert_result = TRUE;
2800 /* Check that what we have left is a sensible domain name. There is no reason
2801 why these domains should in fact use the same syntax as hosts and email
2802 domains, but in practice they seem to. However, there is little point in
2803 actually causing an error here, because that would no doubt hold up incoming
2804 mail. Instead, I'll just log it. */
2806 for (s = domain; *s != 0; s++)
2808 if (!isalnum(*s) && *s != '-' && *s != '.')
2810 log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
2811 "strange characters - is this right?", domain);
2816 /* If there is no key string, construct the query by adding the domain name
2817 onto the inverted host address, and perform a single DNS lookup. */
2821 if (sender_host_address == NULL) return FAIL; /* can never match */
2822 if (revadd[0] == 0) invert_address(revadd, sender_host_address);
2823 frc = string_format(query, sizeof(query), "%s%s", revadd, domain);
2827 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
2828 "(ignored): %s...", query);
2832 rc = one_check_dnsbl(domain, sender_host_address, query, iplist, bitmask,
2833 invert_result, defer_return);
2837 dnslist_domain = string_copy(domain);
2838 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
2839 sender_host_address, domain);
2842 if (rc != FAIL) return rc; /* OK or DEFER */
2845 /* If there is a key string, it can be a list of domains or IP addresses to
2846 be concatenated with the main domain. */
2853 uschar keybuffer[256];
2855 while ((keydomain = string_nextinlist(&key, &keysep, keybuffer,
2856 sizeof(keybuffer))) != NULL)
2858 if (string_is_ip_address(keydomain, NULL) != 0)
2860 uschar keyrevadd[128];
2861 invert_address(keyrevadd, keydomain);
2862 frc = string_format(query, sizeof(query), "%s%s", keyrevadd, domain);
2866 frc = string_format(query, sizeof(query), "%s.%s", keydomain, domain);
2871 log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
2872 "(ignored): %s...", query);
2876 rc = one_check_dnsbl(domain, keydomain, query, iplist, bitmask,
2877 invert_result, defer_return);
2881 dnslist_domain = string_copy(domain);
2882 HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n",
2887 /* If the lookup deferred, remember this fact. We keep trying the rest
2888 of the list to see if we get a useful result, and if we don't, we return
2889 DEFER at the end. */
2891 if (rc == DEFER) defer = TRUE;
2892 } /* continue with next keystring domain/address */
2894 if (defer) return DEFER;
2896 } /* continue with next dnsdb outer domain */
2901 /* End of verify.c */