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Diffstat (limited to '')
| -rw-r--r-- | src/verify.c | 3908 |
1 files changed, 3908 insertions, 0 deletions
diff --git a/src/verify.c b/src/verify.c new file mode 100644 index 0000000..236a87c --- /dev/null +++ b/src/verify.c @@ -0,0 +1,3908 @@ +/************************************************* +* Exim - an Internet mail transport agent * +*************************************************/ + +/* Copyright (c) University of Cambridge 1995 - 2018 */ +/* See the file NOTICE for conditions of use and distribution. */ + +/* Functions concerned with verifying things. The original code for callout +caching was contributed by Kevin Fleming (but I hacked it around a bit). */ + + +#include "exim.h" +#include "transports/smtp.h" + +#define CUTTHROUGH_CMD_TIMEOUT 30 /* timeout for cutthrough-routing calls */ +#define CUTTHROUGH_DATA_TIMEOUT 60 /* timeout for cutthrough-routing calls */ +static smtp_context ctctx; +uschar ctbuffer[8192]; + + +/* Structure for caching DNSBL lookups */ + +typedef struct dnsbl_cache_block { + time_t expiry; + dns_address *rhs; + uschar *text; + int rc; + BOOL text_set; +} dnsbl_cache_block; + + +/* Anchor for DNSBL cache */ + +static tree_node *dnsbl_cache = NULL; + + +/* Bits for match_type in one_check_dnsbl() */ + +#define MT_NOT 1 +#define MT_ALL 2 + +static uschar cutthrough_response(client_conn_ctx *, char, uschar **, int); + + + +/************************************************* +* Retrieve a callout cache record * +*************************************************/ + +/* If a record exists, check whether it has expired. + +Arguments: + dbm_file an open hints file + key the record key + type "address" or "domain" + positive_expire expire time for positive records + negative_expire expire time for negative records + +Returns: the cache record if a non-expired one exists, else NULL +*/ + +static dbdata_callout_cache * +get_callout_cache_record(open_db *dbm_file, const uschar *key, uschar *type, + int positive_expire, int negative_expire) +{ +BOOL negative; +int length, expire; +time_t now; +dbdata_callout_cache *cache_record; + +if (!(cache_record = dbfn_read_with_length(dbm_file, key, &length))) + { + HDEBUG(D_verify) debug_printf("callout cache: no %s record found for %s\n", type, key); + return NULL; + } + +/* We treat a record as "negative" if its result field is not positive, or if +it is a domain record and the postmaster field is negative. */ + +negative = cache_record->result != ccache_accept || + (type[0] == 'd' && cache_record->postmaster_result == ccache_reject); +expire = negative? negative_expire : positive_expire; +now = time(NULL); + +if (now - cache_record->time_stamp > expire) + { + HDEBUG(D_verify) debug_printf("callout cache: %s record expired for %s\n", type, key); + return NULL; + } + +/* If this is a non-reject domain record, check for the obsolete format version +that doesn't have the postmaster and random timestamps, by looking at the +length. If so, copy it to a new-style block, replicating the record's +timestamp. Then check the additional timestamps. (There's no point wasting +effort if connections are rejected.) */ + +if (type[0] == 'd' && cache_record->result != ccache_reject) + { + if (length == sizeof(dbdata_callout_cache_obs)) + { + dbdata_callout_cache *new = store_get(sizeof(dbdata_callout_cache)); + memcpy(new, cache_record, length); + new->postmaster_stamp = new->random_stamp = new->time_stamp; + cache_record = new; + } + + if (now - cache_record->postmaster_stamp > expire) + cache_record->postmaster_result = ccache_unknown; + + if (now - cache_record->random_stamp > expire) + cache_record->random_result = ccache_unknown; + } + +HDEBUG(D_verify) debug_printf("callout cache: found %s record for %s\n", type, key); +return cache_record; +} + + + +/* Check the callout cache. +Options * pm_mailfrom may be modified by cache partial results. + +Return: TRUE if result found +*/ + +static BOOL +cached_callout_lookup(address_item * addr, uschar * address_key, + uschar * from_address, int * opt_ptr, uschar ** pm_ptr, + int * yield, uschar ** failure_ptr, + dbdata_callout_cache * new_domain_record, int * old_domain_res) +{ +int options = *opt_ptr; +open_db dbblock; +open_db *dbm_file = NULL; + +/* Open the callout cache database, it it exists, for reading only at this +stage, unless caching has been disabled. */ + +if (options & vopt_callout_no_cache) + { + HDEBUG(D_verify) debug_printf("callout cache: disabled by no_cache\n"); + } +else if (!(dbm_file = dbfn_open(US"callout", O_RDWR, &dbblock, FALSE))) + { + HDEBUG(D_verify) debug_printf("callout cache: not available\n"); + } +else + { + /* If a cache database is available see if we can avoid the need to do an + actual callout by making use of previously-obtained data. */ + + dbdata_callout_cache_address * cache_address_record; + dbdata_callout_cache * cache_record = get_callout_cache_record(dbm_file, + addr->domain, US"domain", + callout_cache_domain_positive_expire, callout_cache_domain_negative_expire); + + /* If an unexpired cache record was found for this domain, see if the callout + process can be short-circuited. */ + + if (cache_record) + { + /* In most cases, if an early command (up to and including MAIL FROM:<>) + was rejected, there is no point carrying on. The callout fails. However, if + we are doing a recipient verification with use_sender or use_postmaster + set, a previous failure of MAIL FROM:<> doesn't count, because this time we + will be using a non-empty sender. We have to remember this situation so as + not to disturb the cached domain value if this whole verification succeeds + (we don't want it turning into "accept"). */ + + *old_domain_res = cache_record->result; + + if ( cache_record->result == ccache_reject + || *from_address == 0 && cache_record->result == ccache_reject_mfnull) + { + HDEBUG(D_verify) + debug_printf("callout cache: domain gave initial rejection, or " + "does not accept HELO or MAIL FROM:<>\n"); + setflag(addr, af_verify_nsfail); + addr->user_message = US"(result of an earlier callout reused)."; + *yield = FAIL; + *failure_ptr = US"mail"; + dbfn_close(dbm_file); + return TRUE; + } + + /* If a previous check on a "random" local part was accepted, we assume + that the server does not do any checking on local parts. There is therefore + no point in doing the callout, because it will always be successful. If a + random check previously failed, arrange not to do it again, but preserve + the data in the new record. If a random check is required but hasn't been + done, skip the remaining cache processing. */ + + if (options & vopt_callout_random) switch(cache_record->random_result) + { + case ccache_accept: + HDEBUG(D_verify) + debug_printf("callout cache: domain accepts random addresses\n"); + *failure_ptr = US"random"; + dbfn_close(dbm_file); + return TRUE; /* Default yield is OK */ + + case ccache_reject: + HDEBUG(D_verify) + debug_printf("callout cache: domain rejects random addresses\n"); + *opt_ptr = options & ~vopt_callout_random; + new_domain_record->random_result = ccache_reject; + new_domain_record->random_stamp = cache_record->random_stamp; + break; + + default: + HDEBUG(D_verify) + debug_printf("callout cache: need to check random address handling " + "(not cached or cache expired)\n"); + dbfn_close(dbm_file); + return FALSE; + } + + /* If a postmaster check is requested, but there was a previous failure, + there is again no point in carrying on. If a postmaster check is required, + but has not been done before, we are going to have to do a callout, so skip + remaining cache processing. */ + + if (*pm_ptr) + { + if (cache_record->postmaster_result == ccache_reject) + { + setflag(addr, af_verify_pmfail); + HDEBUG(D_verify) + debug_printf("callout cache: domain does not accept " + "RCPT TO:<postmaster@domain>\n"); + *yield = FAIL; + *failure_ptr = US"postmaster"; + setflag(addr, af_verify_pmfail); + addr->user_message = US"(result of earlier verification reused)."; + dbfn_close(dbm_file); + return TRUE; + } + if (cache_record->postmaster_result == ccache_unknown) + { + HDEBUG(D_verify) + debug_printf("callout cache: need to check RCPT " + "TO:<postmaster@domain> (not cached or cache expired)\n"); + dbfn_close(dbm_file); + return FALSE; + } + + /* If cache says OK, set pm_mailfrom NULL to prevent a redundant + postmaster check if the address itself has to be checked. Also ensure + that the value in the cache record is preserved (with its old timestamp). + */ + + HDEBUG(D_verify) debug_printf("callout cache: domain accepts RCPT " + "TO:<postmaster@domain>\n"); + *pm_ptr = NULL; + new_domain_record->postmaster_result = ccache_accept; + new_domain_record->postmaster_stamp = cache_record->postmaster_stamp; + } + } + + /* We can't give a result based on information about the domain. See if there + is an unexpired cache record for this specific address (combined with the + sender address if we are doing a recipient callout with a non-empty sender). + */ + + if (!(cache_address_record = (dbdata_callout_cache_address *) + get_callout_cache_record(dbm_file, address_key, US"address", + callout_cache_positive_expire, callout_cache_negative_expire))) + { + dbfn_close(dbm_file); + return FALSE; + } + + if (cache_address_record->result == ccache_accept) + { + HDEBUG(D_verify) + debug_printf("callout cache: address record is positive\n"); + } + else + { + HDEBUG(D_verify) + debug_printf("callout cache: address record is negative\n"); + addr->user_message = US"Previous (cached) callout verification failure"; + *failure_ptr = US"recipient"; + *yield = FAIL; + } + + /* Close the cache database while we actually do the callout for real. */ + + dbfn_close(dbm_file); + return TRUE; + } +return FALSE; +} + + +/* Write results to callout cache +*/ +static void +cache_callout_write(dbdata_callout_cache * dom_rec, const uschar * domain, + int done, dbdata_callout_cache_address * addr_rec, uschar * address_key) +{ +open_db dbblock; +open_db *dbm_file = NULL; + +/* If we get here with done == TRUE, a successful callout happened, and yield +will be set OK or FAIL according to the response to the RCPT command. +Otherwise, we looped through the hosts but couldn't complete the business. +However, there may be domain-specific information to cache in both cases. + +The value of the result field in the new_domain record is ccache_unknown if +there was an error before or with MAIL FROM:, and errno was not zero, +implying some kind of I/O error. We don't want to write the cache in that case. +Otherwise the value is ccache_accept, ccache_reject, or ccache_reject_mfnull. */ + +if (dom_rec->result != ccache_unknown) + if (!(dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE))) + { + HDEBUG(D_verify) debug_printf("callout cache: not available\n"); + } + else + { + (void)dbfn_write(dbm_file, domain, dom_rec, + (int)sizeof(dbdata_callout_cache)); + HDEBUG(D_verify) debug_printf("wrote callout cache domain record for %s:\n" + " result=%d postmaster=%d random=%d\n", + domain, + dom_rec->result, + dom_rec->postmaster_result, + dom_rec->random_result); + } + +/* If a definite result was obtained for the callout, cache it unless caching +is disabled. */ + +if (done && addr_rec->result != ccache_unknown) + { + if (!dbm_file) + dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE); + if (!dbm_file) + { + HDEBUG(D_verify) debug_printf("no callout cache available\n"); + } + else + { + (void)dbfn_write(dbm_file, address_key, addr_rec, + (int)sizeof(dbdata_callout_cache_address)); + HDEBUG(D_verify) debug_printf("wrote %s callout cache address record for %s\n", + addr_rec->result == ccache_accept ? "positive" : "negative", + address_key); + } + } + +if (dbm_file) dbfn_close(dbm_file); +} + + +/* Cutthrough-multi. If the existing cached cutthrough connection matches +the one we would make for a subsequent recipient, use it. Send the RCPT TO +and check the result, nonpipelined as it may be wanted immediately for +recipient-verification. + +It seems simpler to deal with this case separately from the main callout loop. +We will need to remember it has sent, or not, so that rcpt-acl tail code +can do it there for the non-rcpt-verify case. For this we keep an addresscount. + +Return: TRUE for a definitive result for the recipient +*/ +static int +cutthrough_multi(address_item * addr, host_item * host_list, + transport_feedback * tf, int * yield) +{ +BOOL done = FALSE; +host_item * host; + +if (addr->transport == cutthrough.addr.transport) + for (host = host_list; host; host = host->next) + if (Ustrcmp(host->address, cutthrough.host.address) == 0) + { + int host_af; + uschar *interface = NULL; /* Outgoing interface to use; NULL => any */ + int port = 25; + + deliver_host = host->name; + deliver_host_address = host->address; + deliver_host_port = host->port; + deliver_domain = addr->domain; + transport_name = addr->transport->name; + + host_af = Ustrchr(host->address, ':') ? AF_INET6 : AF_INET; + + if ( !smtp_get_interface(tf->interface, host_af, addr, &interface, + US"callout") + || !smtp_get_port(tf->port, addr, &port, US"callout") + ) + log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address, + addr->message); + + smtp_port_for_connect(host, port); + + if ( ( interface == cutthrough.interface + || ( interface + && cutthrough.interface + && Ustrcmp(interface, cutthrough.interface) == 0 + ) ) + && host->port == cutthrough.host.port + ) + { + uschar * resp = NULL; + + /* Match! Send the RCPT TO, set done from the response */ + done = + smtp_write_command(&ctctx, SCMD_FLUSH, "RCPT TO:<%.1000s>\r\n", + transport_rcpt_address(addr, + addr->transport->rcpt_include_affixes)) >= 0 + && cutthrough_response(&cutthrough.cctx, '2', &resp, + CUTTHROUGH_DATA_TIMEOUT) == '2'; + + /* This would go horribly wrong if a callout fail was ignored by ACL. + We punt by abandoning cutthrough on a reject, like the + first-rcpt does. */ + + if (done) + { + address_item * na = store_get(sizeof(address_item)); + *na = cutthrough.addr; + cutthrough.addr = *addr; + cutthrough.addr.host_used = &cutthrough.host; + cutthrough.addr.next = na; + + cutthrough.nrcpt++; + } + else + { + cancel_cutthrough_connection(TRUE, US"recipient rejected"); + if (!resp || errno == ETIMEDOUT) + { + HDEBUG(D_verify) debug_printf("SMTP timeout\n"); + } + else if (errno == 0) + { + if (*resp == 0) + Ustrcpy(resp, US"connection dropped"); + + addr->message = + string_sprintf("response to \"%s\" was: %s", + big_buffer, string_printing(resp)); + + addr->user_message = + string_sprintf("Callout verification failed:\n%s", resp); + + /* Hard rejection ends the process */ + + if (resp[0] == '5') /* Address rejected */ + { + *yield = FAIL; + done = TRUE; + } + } + } + } + break; /* host_list */ + } +if (!done) + cancel_cutthrough_connection(TRUE, US"incompatible connection"); +return done; +} + + +/************************************************* +* Do callout verification for an address * +*************************************************/ + +/* This function is called from verify_address() when the address has routed to +a host list, and a callout has been requested. Callouts are expensive; that is +why a cache is used to improve the efficiency. + +Arguments: + addr the address that's been routed + host_list the list of hosts to try + tf the transport feedback block + + ifstring "interface" option from transport, or NULL + portstring "port" option from transport, or NULL + protocolstring "protocol" option from transport, or NULL + callout the per-command callout timeout + callout_overall the overall callout timeout (if < 0 use 4*callout) + callout_connect the callout connection timeout (if < 0 use callout) + options the verification options - these bits are used: + vopt_is_recipient => this is a recipient address + vopt_callout_no_cache => don't use callout cache + vopt_callout_fullpm => if postmaster check, do full one + vopt_callout_random => do the "random" thing + vopt_callout_recipsender => use real sender for recipient + vopt_callout_recippmaster => use postmaster for recipient + vopt_callout_hold => lazy close connection + se_mailfrom MAIL FROM address for sender verify; NULL => "" + pm_mailfrom if non-NULL, do the postmaster check with this sender + +Returns: OK/FAIL/DEFER +*/ + +static int +do_callout(address_item *addr, host_item *host_list, transport_feedback *tf, + int callout, int callout_overall, int callout_connect, int options, + uschar *se_mailfrom, uschar *pm_mailfrom) +{ +int yield = OK; +int old_domain_cache_result = ccache_accept; +BOOL done = FALSE; +uschar *address_key; +uschar *from_address; +uschar *random_local_part = NULL; +const uschar *save_deliver_domain = deliver_domain; +uschar **failure_ptr = options & vopt_is_recipient + ? &recipient_verify_failure : &sender_verify_failure; +dbdata_callout_cache new_domain_record; +dbdata_callout_cache_address new_address_record; +time_t callout_start_time; + +new_domain_record.result = ccache_unknown; +new_domain_record.postmaster_result = ccache_unknown; +new_domain_record.random_result = ccache_unknown; + +memset(&new_address_record, 0, sizeof(new_address_record)); + +/* For a recipient callout, the key used for the address cache record must +include the sender address if we are using the real sender in the callout, +because that may influence the result of the callout. */ + +if (options & vopt_is_recipient) + if (options & vopt_callout_recipsender) + { + from_address = sender_address; + address_key = string_sprintf("%s/<%s>", addr->address, sender_address); + if (cutthrough.delivery) options |= vopt_callout_no_cache; + } + else if (options & vopt_callout_recippmaster) + { + from_address = string_sprintf("postmaster@%s", qualify_domain_sender); + address_key = string_sprintf("%s/<postmaster@%s>", addr->address, + qualify_domain_sender); + } + else + { + from_address = US""; + address_key = addr->address; + } + +/* For a sender callout, we must adjust the key if the mailfrom address is not +empty. */ + +else + { + from_address = se_mailfrom ? se_mailfrom : US""; + address_key = *from_address + ? string_sprintf("%s/<%s>", addr->address, from_address) : addr->address; + } + +if (cached_callout_lookup(addr, address_key, from_address, + &options, &pm_mailfrom, &yield, failure_ptr, + &new_domain_record, &old_domain_cache_result)) + { + cancel_cutthrough_connection(TRUE, US"cache-hit"); + goto END_CALLOUT; + } + +if (!addr->transport) + { + HDEBUG(D_verify) debug_printf("cannot callout via null transport\n"); + } +else if (Ustrcmp(addr->transport->driver_name, "smtp") != 0) + log_write(0, LOG_MAIN|LOG_PANIC|LOG_CONFIG_FOR, "callout transport '%s': %s is non-smtp", + addr->transport->name, addr->transport->driver_name); +else + { + smtp_transport_options_block *ob = + (smtp_transport_options_block *)addr->transport->options_block; + host_item * host; + + /* The information wasn't available in the cache, so we have to do a real + callout and save the result in the cache for next time, unless no_cache is set, + or unless we have a previously cached negative random result. If we are to test + with a random local part, ensure that such a local part is available. If not, + log the fact, but carry on without randomising. */ + + if (options & vopt_callout_random && callout_random_local_part) + if (!(random_local_part = expand_string(callout_random_local_part))) + log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand " + "callout_random_local_part: %s", expand_string_message); + + /* Default the connect and overall callout timeouts if not set, and record the + time we are starting so that we can enforce it. */ + + if (callout_overall < 0) callout_overall = 4 * callout; + if (callout_connect < 0) callout_connect = callout; + callout_start_time = time(NULL); + + /* Before doing a real callout, if this is an SMTP connection, flush the SMTP + output because a callout might take some time. When PIPELINING is active and + there are many recipients, the total time for doing lots of callouts can add up + and cause the client to time out. So in this case we forgo the PIPELINING + optimization. */ + + if (smtp_out && !f.disable_callout_flush) mac_smtp_fflush(); + + clearflag(addr, af_verify_pmfail); /* postmaster callout flag */ + clearflag(addr, af_verify_nsfail); /* null sender callout flag */ + +/* cutthrough-multi: if a nonfirst rcpt has the same routing as the first, +and we are holding a cutthrough conn open, we can just append the rcpt to +that conn for verification purposes (and later delivery also). Simplest +coding means skipping this whole loop and doing the append separately. */ + + /* Can we re-use an open cutthrough connection? */ + if ( cutthrough.cctx.sock >= 0 + && (options & (vopt_callout_recipsender | vopt_callout_recippmaster)) + == vopt_callout_recipsender + && !random_local_part + && !pm_mailfrom + ) + done = cutthrough_multi(addr, host_list, tf, &yield); + + /* If we did not use a cached connection, make connections to the hosts + and do real callouts. The list of hosts is passed in as an argument. */ + + for (host = host_list; host && !done; host = host->next) + { + int host_af; + int port = 25; + uschar *interface = NULL; /* Outgoing interface to use; NULL => any */ + smtp_context sx; + + if (!host->address) + { + DEBUG(D_verify) debug_printf("no IP address for host name %s: skipping\n", + host->name); + continue; + } + + /* Check the overall callout timeout */ + + if (time(NULL) - callout_start_time >= callout_overall) + { + HDEBUG(D_verify) debug_printf("overall timeout for callout exceeded\n"); + break; + } + + /* Set IPv4 or IPv6 */ + + host_af = Ustrchr(host->address, ':') ? AF_INET6 : AF_INET; + + /* Expand and interpret the interface and port strings. The latter will not + be used if there is a host-specific port (e.g. from a manualroute router). + This has to be delayed till now, because they may expand differently for + different hosts. If there's a failure, log it, but carry on with the + defaults. */ + + deliver_host = host->name; + deliver_host_address = host->address; + deliver_host_port = host->port; + deliver_domain = addr->domain; + transport_name = addr->transport->name; + + if ( !smtp_get_interface(tf->interface, host_af, addr, &interface, + US"callout") + || !smtp_get_port(tf->port, addr, &port, US"callout") + ) + log_write(0, LOG_MAIN|LOG_PANIC, "<%s>: %s", addr->address, + addr->message); + + sx.addrlist = addr; + sx.conn_args.host = host; + sx.conn_args.host_af = host_af, + sx.port = port; + sx.conn_args.interface = interface; + sx.helo_data = tf->helo_data; + sx.conn_args.tblock = addr->transport; + sx.verify = TRUE; + +tls_retry_connection: + /* Set the address state so that errors are recorded in it */ + + addr->transport_return = PENDING_DEFER; + ob->connect_timeout = callout_connect; + ob->command_timeout = callout; + + /* Get the channel set up ready for a message (MAIL FROM being the next + SMTP command to send. If we tried TLS but it failed, try again without + if permitted */ + + yield = smtp_setup_conn(&sx, FALSE); +#ifdef SUPPORT_TLS + if ( yield == DEFER + && addr->basic_errno == ERRNO_TLSFAILURE + && ob->tls_tempfail_tryclear + && verify_check_given_host(CUSS &ob->hosts_require_tls, host) != OK + ) + { + log_write(0, LOG_MAIN, + "%s: callout unencrypted to %s [%s] (not in hosts_require_tls)", + addr->message, host->name, host->address); + addr->transport_return = PENDING_DEFER; + yield = smtp_setup_conn(&sx, TRUE); + } +#endif + if (yield != OK) + { + errno = addr->basic_errno; + transport_name = NULL; + deliver_host = deliver_host_address = NULL; + deliver_domain = save_deliver_domain; + + /* Failure to accept HELO is cached; this blocks the whole domain for all + senders. I/O errors and defer responses are not cached. */ + + if (yield == FAIL && (errno == 0 || errno == ERRNO_SMTPCLOSED)) + { + setflag(addr, af_verify_nsfail); + new_domain_record.result = ccache_reject; + done = TRUE; + } + else + done = FALSE; + goto no_conn; + } + + /* If we needed to authenticate, smtp_setup_conn() did that. Copy + the AUTH info for logging */ + + addr->authenticator = client_authenticator; + addr->auth_id = client_authenticated_id; + + sx.from_addr = from_address; + sx.first_addr = sx.sync_addr = addr; + sx.ok = FALSE; /*XXX these 3 last might not be needed for verify? */ + sx.send_rset = TRUE; + sx.completed_addr = FALSE; + + new_domain_record.result = old_domain_cache_result == ccache_reject_mfnull + ? ccache_reject_mfnull : ccache_accept; + + /* Do the random local part check first. Temporarily replace the recipient + with the "random" value */ + + if (random_local_part) + { + uschar * main_address = addr->address; + const uschar * rcpt_domain = addr->domain; + +#ifdef SUPPORT_I18N + uschar * errstr = NULL; + if ( testflag(addr, af_utf8_downcvt) + && (rcpt_domain = string_domain_utf8_to_alabel(rcpt_domain, + &errstr), errstr) + ) + { + addr->message = errstr; + errno = ERRNO_EXPANDFAIL; + setflag(addr, af_verify_nsfail); + done = FALSE; + rcpt_domain = US""; /*XXX errorhandling! */ + } +#endif + + /* This would be ok for 1st rcpt of a cutthrough (the case handled here; + subsequents are done in cutthrough_multi()), but no way to + handle a subsequent because of the RSET vaporising the MAIL FROM. + So refuse to support any. Most cutthrough use will not involve + random_local_part, so no loss. */ + cancel_cutthrough_connection(TRUE, US"random-recipient"); + + addr->address = string_sprintf("%s@%.1000s", + random_local_part, rcpt_domain); + done = FALSE; + + /* If accepted, we aren't going to do any further tests below. + Otherwise, cache a real negative response, and get back to the right + state to send RCPT. Unless there's some problem such as a dropped + connection, we expect to succeed, because the commands succeeded above. + However, some servers drop the connection after responding to an + invalid recipient, so on (any) error we drop and remake the connection. + XXX We don't care about that for postmaster_full. Should we? + + XXX could we add another flag to the context, and have the common + code emit the RSET too? Even pipelined after the RCPT... + Then the main-verify call could use it if there's to be a subsequent + postmaster-verify. + The sync_responses() would need to be taught about it and we'd + need another return code filtering out to here. + + Avoid using a SIZE option on the MAIL for all random-rcpt checks. + */ + + sx.avoid_option = OPTION_SIZE; + + /* Remember when we last did a random test */ + new_domain_record.random_stamp = time(NULL); + + if (smtp_write_mail_and_rcpt_cmds(&sx, &yield) == 0) + switch(addr->transport_return) + { + case PENDING_OK: /* random was accepted, unfortunately */ + new_domain_record.random_result = ccache_accept; + yield = OK; /* Only usable verify result we can return */ + done = TRUE; + *failure_ptr = US"random"; + goto no_conn; + case FAIL: /* rejected: the preferred result */ + new_domain_record.random_result = ccache_reject; + sx.avoid_option = 0; + + /* Between each check, issue RSET, because some servers accept only + one recipient after MAIL FROM:<>. + XXX We don't care about that for postmaster_full. Should we? */ + + if ((done = + smtp_write_command(&sx, SCMD_FLUSH, "RSET\r\n") >= 0 && + smtp_read_response(&sx, sx.buffer, sizeof(sx.buffer), '2', callout))) + break; + + HDEBUG(D_acl|D_v) + debug_printf_indent("problem after random/rset/mfrom; reopen conn\n"); + random_local_part = NULL; +#ifdef SUPPORT_TLS + tls_close(sx.cctx.tls_ctx, TLS_SHUTDOWN_NOWAIT); +#endif + HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP(close)>>\n"); + (void)close(sx.cctx.sock); + sx.cctx.sock = -1; +#ifndef DISABLE_EVENT + (void) event_raise(addr->transport->event_action, + US"tcp:close", NULL); +#endif + addr->address = main_address; + addr->transport_return = PENDING_DEFER; + sx.first_addr = sx.sync_addr = addr; + sx.ok = FALSE; + sx.send_rset = TRUE; + sx.completed_addr = FALSE; + goto tls_retry_connection; + case DEFER: /* 4xx response to random */ + break; /* Just to be clear. ccache_unknown, !done. */ + } + + /* Re-setup for main verify, or for the error message when failing */ + addr->address = main_address; + addr->transport_return = PENDING_DEFER; + sx.first_addr = sx.sync_addr = addr; + sx.ok = FALSE; + sx.send_rset = TRUE; + sx.completed_addr = FALSE; + } + else + done = TRUE; + + /* Main verify. For rcpt-verify use SIZE if we know it and we're not cacheing; + for sndr-verify never use it. */ + + if (done) + { + if (!(options & vopt_is_recipient && options & vopt_callout_no_cache)) + sx.avoid_option = OPTION_SIZE; + + done = FALSE; + switch(smtp_write_mail_and_rcpt_cmds(&sx, &yield)) + { + case 0: switch(addr->transport_return) /* ok so far */ + { + case PENDING_OK: done = TRUE; + new_address_record.result = ccache_accept; + break; + case FAIL: done = TRUE; + yield = FAIL; + *failure_ptr = US"recipient"; + new_address_record.result = ccache_reject; + break; + default: break; + } + break; + + case -1: /* MAIL response error */ + *failure_ptr = US"mail"; + if (errno == 0 && sx.buffer[0] == '5') + { + setflag(addr, af_verify_nsfail); + if (from_address[0] == 0) + new_domain_record.result = ccache_reject_mfnull; + } + break; + /* non-MAIL read i/o error */ + /* non-MAIL response timeout */ + /* internal error; channel still usable */ + default: break; /* transmit failed */ + } + } + + addr->auth_sndr = client_authenticated_sender; + + deliver_host = deliver_host_address = NULL; + deliver_domain = save_deliver_domain; + + /* Do postmaster check if requested; if a full check is required, we + check for RCPT TO:<postmaster> (no domain) in accordance with RFC 821. */ + + if (done && pm_mailfrom) + { + /* Could possibly shift before main verify, just above, and be ok + for cutthrough. But no way to handle a subsequent rcpt, so just + refuse any */ + cancel_cutthrough_connection(TRUE, US"postmaster verify"); + HDEBUG(D_acl|D_v) debug_printf_indent("Cutthrough cancelled by presence of postmaster verify\n"); + + done = smtp_write_command(&sx, SCMD_FLUSH, "RSET\r\n") >= 0 + && smtp_read_response(&sx, sx.buffer, sizeof(sx.buffer), '2', callout); + + if (done) + { + uschar * main_address = addr->address; + + /*XXX oops, affixes */ + addr->address = string_sprintf("postmaster@%.1000s", addr->domain); + addr->transport_return = PENDING_DEFER; + + sx.from_addr = pm_mailfrom; + sx.first_addr = sx.sync_addr = addr; + sx.ok = FALSE; + sx.send_rset = TRUE; + sx.completed_addr = FALSE; + sx.avoid_option = OPTION_SIZE; + + if( smtp_write_mail_and_rcpt_cmds(&sx, &yield) == 0 + && addr->transport_return == PENDING_OK + ) + done = TRUE; + else + done = (options & vopt_callout_fullpm) != 0 + && smtp_write_command(&sx, SCMD_FLUSH, + "RCPT TO:<postmaster>\r\n") >= 0 + && smtp_read_response(&sx, sx.buffer, + sizeof(sx.buffer), '2', callout); + + /* Sort out the cache record */ + + new_domain_record.postmaster_stamp = time(NULL); + + if (done) + new_domain_record.postmaster_result = ccache_accept; + else if (errno == 0 && sx.buffer[0] == '5') + { + *failure_ptr = US"postmaster"; + setflag(addr, af_verify_pmfail); + new_domain_record.postmaster_result = ccache_reject; + } + + addr->address = main_address; + } + } + /* For any failure of the main check, other than a negative response, we just + close the connection and carry on. We can identify a negative response by the + fact that errno is zero. For I/O errors it will be non-zero + + Set up different error texts for logging and for sending back to the caller + as an SMTP response. Log in all cases, using a one-line format. For sender + callouts, give a full response to the caller, but for recipient callouts, + don't give the IP address because this may be an internal host whose identity + is not to be widely broadcast. */ + +no_conn: + switch(errno) + { + case ETIMEDOUT: + HDEBUG(D_verify) debug_printf("SMTP timeout\n"); + sx.send_quit = FALSE; + break; + +#ifdef SUPPORT_I18N + case ERRNO_UTF8_FWD: + { + extern int acl_where; /* src/acl.c */ + errno = 0; + addr->message = string_sprintf( + "response to \"EHLO\" did not include SMTPUTF8"); + addr->user_message = acl_where == ACL_WHERE_RCPT + ? US"533 no support for internationalised mailbox name" + : US"550 mailbox unavailable"; + yield = FAIL; + done = TRUE; + } + break; +#endif +#if defined(SUPPORT_TLS) && defined(EXPERIMENTAL_REQUIRETLS) + case ERRNO_REQUIRETLS: + addr->user_message = US"530 5.7.4 REQUIRETLS support required"; + yield = FAIL; + done = TRUE; + break; +#endif + case ECONNREFUSED: + sx.send_quit = FALSE; + break; + + case 0: + if (*sx.buffer == 0) Ustrcpy(sx.buffer, US"connection dropped"); + + /*XXX test here is ugly; seem to have a split of responsibility for + building this message. Need to rationalise. Where is it done + before here, and when not? + Not == 5xx resp to MAIL on main-verify + */ + if (!addr->message) addr->message = + string_sprintf("response to \"%s\" was: %s", + big_buffer, string_printing(sx.buffer)); + + addr->user_message = options & vopt_is_recipient + ? string_sprintf("Callout verification failed:\n%s", sx.buffer) + : string_sprintf("Called: %s\nSent: %s\nResponse: %s", + host->address, big_buffer, sx.buffer); + + /* Hard rejection ends the process */ + + if (sx.buffer[0] == '5') /* Address rejected */ + { + yield = FAIL; + done = TRUE; + } + break; + } + + /* End the SMTP conversation and close the connection. */ + + /* Cutthrough - on a successful connect and recipient-verify with + use-sender and we are 1st rcpt and have no cutthrough conn so far + here is where we want to leave the conn open. Ditto for a lazy-close + verify. */ + + if (cutthrough.delivery) + { + if (addr->transport->filter_command) + { + cutthrough.delivery= FALSE; + HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of transport filter\n"); + } +#ifndef DISABLE_DKIM + if (ob->dkim.dkim_domain) + { + cutthrough.delivery= FALSE; + HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of DKIM signing\n"); + } +#endif +#ifdef EXPERIMENTAL_ARC + if (ob->arc_sign) + { + cutthrough.delivery= FALSE; + HDEBUG(D_acl|D_v) debug_printf("Cutthrough cancelled by presence of ARC signing\n"); + } +#endif + } + + if ( (cutthrough.delivery || options & vopt_callout_hold) + && rcpt_count == 1 + && done + && yield == OK + && (options & (vopt_callout_recipsender|vopt_callout_recippmaster|vopt_success_on_redirect)) + == vopt_callout_recipsender + && !random_local_part + && !pm_mailfrom + && cutthrough.cctx.sock < 0 + && !sx.lmtp + ) + { + address_item * parent, * caddr; + + HDEBUG(D_acl|D_v) debug_printf_indent("holding verify callout open for %s\n", + cutthrough.delivery + ? "cutthrough delivery" : "potential further verifies and delivery"); + + cutthrough.callout_hold_only = !cutthrough.delivery; + cutthrough.is_tls = tls_out.active.sock >= 0; + /* We assume no buffer in use in the outblock */ + cutthrough.cctx = sx.cctx; + cutthrough.nrcpt = 1; + cutthrough.transport = addr->transport->name; + cutthrough.interface = interface; + cutthrough.snd_port = sending_port; + cutthrough.peer_options = smtp_peer_options; + cutthrough.host = *host; + { + int oldpool = store_pool; + store_pool = POOL_PERM; + cutthrough.snd_ip = string_copy(sending_ip_address); + cutthrough.host.name = string_copy(host->name); + cutthrough.host.address = string_copy(host->address); + store_pool = oldpool; + } + + /* Save the address_item and parent chain for later logging */ + cutthrough.addr = *addr; + cutthrough.addr.next = NULL; + cutthrough.addr.host_used = &cutthrough.host; + for (caddr = &cutthrough.addr, parent = addr->parent; + parent; + caddr = caddr->parent, parent = parent->parent) + *(caddr->parent = store_get(sizeof(address_item))) = *parent; + + ctctx.outblock.buffer = ctbuffer; + ctctx.outblock.buffersize = sizeof(ctbuffer); + ctctx.outblock.ptr = ctbuffer; + /* ctctx.outblock.cmd_count = 0; ctctx.outblock.authenticating = FALSE; */ + ctctx.outblock.cctx = &cutthrough.cctx; + } + else + { + /* Ensure no cutthrough on multiple verifies that were incompatible */ + if (options & vopt_callout_recipsender) + cancel_cutthrough_connection(TRUE, US"not usable for cutthrough"); + if (sx.send_quit) + { + (void) smtp_write_command(&sx, SCMD_FLUSH, "QUIT\r\n"); + + /* Wait a short time for response, and discard it */ + smtp_read_response(&sx, sx.buffer, sizeof(sx.buffer), '2', 1); + } + + if (sx.cctx.sock >= 0) + { +#ifdef SUPPORT_TLS + if (sx.cctx.tls_ctx) + { + tls_close(sx.cctx.tls_ctx, TLS_SHUTDOWN_NOWAIT); + sx.cctx.tls_ctx = NULL; + } +#endif + HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP(close)>>\n"); + (void)close(sx.cctx.sock); + sx.cctx.sock = -1; +#ifndef DISABLE_EVENT + (void) event_raise(addr->transport->event_action, US"tcp:close", NULL); +#endif + } + } + + if (!done || yield != OK) + addr->message = string_sprintf("%s [%s] : %s", host->name, host->address, + addr->message); + } /* Loop through all hosts, while !done */ + } + +/* If we get here with done == TRUE, a successful callout happened, and yield +will be set OK or FAIL according to the response to the RCPT command. +Otherwise, we looped through the hosts but couldn't complete the business. +However, there may be domain-specific information to cache in both cases. */ + +if (!(options & vopt_callout_no_cache)) + cache_callout_write(&new_domain_record, addr->domain, + done, &new_address_record, address_key); + +/* Failure to connect to any host, or any response other than 2xx or 5xx is a +temporary error. If there was only one host, and a response was received, leave +it alone if supplying details. Otherwise, give a generic response. */ + +if (!done) + { + uschar * dullmsg = string_sprintf("Could not complete %s verify callout", + options & vopt_is_recipient ? "recipient" : "sender"); + yield = DEFER; + + addr->message = host_list->next || !addr->message + ? dullmsg : string_sprintf("%s: %s", dullmsg, addr->message); + + addr->user_message = smtp_return_error_details + ? string_sprintf("%s for <%s>.\n" + "The mail server(s) for the domain may be temporarily unreachable, or\n" + "they may be permanently unreachable from this server. In the latter case,\n%s", + dullmsg, addr->address, + options & vopt_is_recipient + ? "the address will never be accepted." + : "you need to change the address or create an MX record for its domain\n" + "if it is supposed to be generally accessible from the Internet.\n" + "Talk to your mail administrator for details.") + : dullmsg; + + /* Force a specific error code */ + + addr->basic_errno = ERRNO_CALLOUTDEFER; + } + +/* Come here from within the cache-reading code on fast-track exit. */ + +END_CALLOUT: +tls_modify_variables(&tls_in); +return yield; +} + + + +/* Called after recipient-acl to get a cutthrough connection open when + one was requested and a recipient-verify wasn't subsequently done. +*/ +int +open_cutthrough_connection(address_item * addr) +{ +address_item addr2; +int rc; + +/* Use a recipient-verify-callout to set up the cutthrough connection. */ +/* We must use a copy of the address for verification, because it might +get rewritten. */ + +addr2 = *addr; +HDEBUG(D_acl) debug_printf_indent("----------- %s cutthrough setup ------------\n", + rcpt_count > 1 ? "more" : "start"); +rc = verify_address(&addr2, NULL, + vopt_is_recipient | vopt_callout_recipsender | vopt_callout_no_cache, + CUTTHROUGH_CMD_TIMEOUT, -1, -1, + NULL, NULL, NULL); +addr->message = addr2.message; +addr->user_message = addr2.user_message; +HDEBUG(D_acl) debug_printf_indent("----------- end cutthrough setup ------------\n"); +return rc; +} + + + +/* Send given number of bytes from the buffer */ +static BOOL +cutthrough_send(int n) +{ +if(cutthrough.cctx.sock < 0) + return TRUE; + +if( +#ifdef SUPPORT_TLS + cutthrough.is_tls + ? tls_write(cutthrough.cctx.tls_ctx, ctctx.outblock.buffer, n, FALSE) + : +#endif + send(cutthrough.cctx.sock, ctctx.outblock.buffer, n, 0) > 0 + ) +{ + transport_count += n; + ctctx.outblock.ptr= ctctx.outblock.buffer; + return TRUE; +} + +HDEBUG(D_transport|D_acl) debug_printf_indent("cutthrough_send failed: %s\n", strerror(errno)); +return FALSE; +} + + + +static BOOL +_cutthrough_puts(uschar * cp, int n) +{ +while(n--) + { + if(ctctx.outblock.ptr >= ctctx.outblock.buffer+ctctx.outblock.buffersize) + if(!cutthrough_send(ctctx.outblock.buffersize)) + return FALSE; + + *ctctx.outblock.ptr++ = *cp++; + } +return TRUE; +} + +/* Buffered output of counted data block. Return boolean success */ +static BOOL +cutthrough_puts(uschar * cp, int n) +{ +if (cutthrough.cctx.sock < 0) return TRUE; +if (_cutthrough_puts(cp, n)) return TRUE; +cancel_cutthrough_connection(TRUE, US"transmit failed"); +return FALSE; +} + +void +cutthrough_data_puts(uschar * cp, int n) +{ +if (cutthrough.delivery) (void) cutthrough_puts(cp, n); +return; +} + + +static BOOL +_cutthrough_flush_send(void) +{ +int n = ctctx.outblock.ptr - ctctx.outblock.buffer; + +if(n>0) + if(!cutthrough_send(n)) + return FALSE; +return TRUE; +} + + +/* Send out any bufferred output. Return boolean success. */ +BOOL +cutthrough_flush_send(void) +{ +if (_cutthrough_flush_send()) return TRUE; +cancel_cutthrough_connection(TRUE, US"transmit failed"); +return FALSE; +} + + +static BOOL +cutthrough_put_nl(void) +{ +return cutthrough_puts(US"\r\n", 2); +} + + +void +cutthrough_data_put_nl(void) +{ +cutthrough_data_puts(US"\r\n", 2); +} + + +/* Get and check response from cutthrough target */ +static uschar +cutthrough_response(client_conn_ctx * cctx, char expect, uschar ** copy, int timeout) +{ +smtp_context sx = {0}; +uschar inbuffer[4096]; +uschar responsebuffer[4096]; + +sx.inblock.buffer = inbuffer; +sx.inblock.buffersize = sizeof(inbuffer); +sx.inblock.ptr = inbuffer; +sx.inblock.ptrend = inbuffer; +sx.inblock.cctx = cctx; +if(!smtp_read_response(&sx, responsebuffer, sizeof(responsebuffer), expect, timeout)) + cancel_cutthrough_connection(TRUE, US"target timeout on read"); + +if(copy) + { + uschar * cp; + *copy = cp = string_copy(responsebuffer); + /* Trim the trailing end of line */ + cp += Ustrlen(responsebuffer); + if(cp > *copy && cp[-1] == '\n') *--cp = '\0'; + if(cp > *copy && cp[-1] == '\r') *--cp = '\0'; + } + +return responsebuffer[0]; +} + + +/* Negotiate dataphase with the cutthrough target, returning success boolean */ +BOOL +cutthrough_predata(void) +{ +if(cutthrough.cctx.sock < 0 || cutthrough.callout_hold_only) + return FALSE; + +HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP>> DATA\n"); +cutthrough_puts(US"DATA\r\n", 6); +cutthrough_flush_send(); + +/* Assume nothing buffered. If it was it gets ignored. */ +return cutthrough_response(&cutthrough.cctx, '3', NULL, CUTTHROUGH_DATA_TIMEOUT) == '3'; +} + + +/* tctx arg only to match write_chunk() */ +static BOOL +cutthrough_write_chunk(transport_ctx * tctx, uschar * s, int len) +{ +uschar * s2; +while(s && (s2 = Ustrchr(s, '\n'))) + { + if(!cutthrough_puts(s, s2-s) || !cutthrough_put_nl()) + return FALSE; + s = s2+1; + } +return TRUE; +} + + +/* Buffered send of headers. Return success boolean. */ +/* Expands newlines to wire format (CR,NL). */ +/* Also sends header-terminating blank line. */ +BOOL +cutthrough_headers_send(void) +{ +transport_ctx tctx; + +if(cutthrough.cctx.sock < 0 || cutthrough.callout_hold_only) + return FALSE; + +/* We share a routine with the mainline transport to handle header add/remove/rewrites, + but having a separate buffered-output function (for now) +*/ +HDEBUG(D_acl) debug_printf_indent("----------- start cutthrough headers send -----------\n"); + +tctx.u.fd = cutthrough.cctx.sock; +tctx.tblock = cutthrough.addr.transport; +tctx.addr = &cutthrough.addr; +tctx.check_string = US"."; +tctx.escape_string = US".."; +/*XXX check under spool_files_wireformat. Might be irrelevant */ +tctx.options = topt_use_crlf; + +if (!transport_headers_send(&tctx, &cutthrough_write_chunk)) + return FALSE; + +HDEBUG(D_acl) debug_printf_indent("----------- done cutthrough headers send ------------\n"); +return TRUE; +} + + +static void +close_cutthrough_connection(const uschar * why) +{ +int fd = cutthrough.cctx.sock; +if(fd >= 0) + { + /* We could be sending this after a bunch of data, but that is ok as + the only way to cancel the transfer in dataphase is to drop the tcp + conn before the final dot. + */ + client_conn_ctx tmp_ctx = cutthrough.cctx; + ctctx.outblock.ptr = ctbuffer; + HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP>> QUIT\n"); + _cutthrough_puts(US"QUIT\r\n", 6); /* avoid recursion */ + _cutthrough_flush_send(); + cutthrough.cctx.sock = -1; /* avoid recursion via read timeout */ + cutthrough.nrcpt = 0; /* permit re-cutthrough on subsequent message */ + + /* Wait a short time for response, and discard it */ + cutthrough_response(&tmp_ctx, '2', NULL, 1); + +#ifdef SUPPORT_TLS + if (cutthrough.is_tls) + { + tls_close(cutthrough.cctx.tls_ctx, TLS_SHUTDOWN_NOWAIT); + cutthrough.cctx.tls_ctx = NULL; + cutthrough.is_tls = FALSE; + } +#endif + HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP(close)>>\n"); + (void)close(fd); + HDEBUG(D_acl) debug_printf_indent("----------- cutthrough shutdown (%s) ------------\n", why); + } +ctctx.outblock.ptr = ctbuffer; +} + +void +cancel_cutthrough_connection(BOOL close_noncutthrough_verifies, const uschar * why) +{ +if (cutthrough.delivery || close_noncutthrough_verifies) + close_cutthrough_connection(why); +cutthrough.delivery = cutthrough.callout_hold_only = FALSE; +} + + +void +release_cutthrough_connection(const uschar * why) +{ +if (cutthrough.cctx.sock < 0) return; +HDEBUG(D_acl) debug_printf_indent("release cutthrough conn: %s\n", why); +cutthrough.cctx.sock = -1; +cutthrough.cctx.tls_ctx = NULL; +cutthrough.delivery = cutthrough.callout_hold_only = FALSE; +} + + + + +/* Have senders final-dot. Send one to cutthrough target, and grab the response. + Log an OK response as a transmission. + Close the connection. + Return smtp response-class digit. +*/ +uschar * +cutthrough_finaldot(void) +{ +uschar res; +address_item * addr; +HDEBUG(D_transport|D_acl|D_v) debug_printf_indent(" SMTP>> .\n"); + +/* Assume data finshed with new-line */ +if( !cutthrough_puts(US".", 1) + || !cutthrough_put_nl() + || !cutthrough_flush_send() + ) + return cutthrough.addr.message; + +res = cutthrough_response(&cutthrough.cctx, '2', &cutthrough.addr.message, + CUTTHROUGH_DATA_TIMEOUT); +for (addr = &cutthrough.addr; addr; addr = addr->next) + { + addr->message = cutthrough.addr.message; + switch(res) + { + case '2': + delivery_log(LOG_MAIN, addr, (int)'>', NULL); + close_cutthrough_connection(US"delivered"); + break; + + case '4': + delivery_log(LOG_MAIN, addr, 0, + US"tmp-reject from cutthrough after DATA:"); + break; + + case '5': + delivery_log(LOG_MAIN|LOG_REJECT, addr, 0, + US"rejected after DATA:"); + break; + + default: + break; + } + } +return cutthrough.addr.message; +} + + + +/************************************************* +* Copy error to toplevel address * +*************************************************/ + +/* This function is used when a verify fails or defers, to ensure that the +failure or defer information is in the original toplevel address. This applies +when an address is redirected to a single new address, and the failure or +deferral happens to the child address. + +Arguments: + vaddr the verify address item + addr the final address item + yield FAIL or DEFER + +Returns: the value of YIELD +*/ + +static int +copy_error(address_item *vaddr, address_item *addr, int yield) +{ +if (addr != vaddr) + { + vaddr->message = addr->message; + vaddr->user_message = addr->user_message; + vaddr->basic_errno = addr->basic_errno; + vaddr->more_errno = addr->more_errno; + vaddr->prop.address_data = addr->prop.address_data; + copyflag(vaddr, addr, af_pass_message); + } +return yield; +} + + + + +/************************************************** +* printf that automatically handles TLS if needed * +***************************************************/ + +/* This function is used by verify_address() as a substitute for all fprintf() +calls; a direct fprintf() will not produce output in a TLS SMTP session, such +as a response to an EXPN command. smtp_in.c makes smtp_printf available but +that assumes that we always use the smtp_out FILE* when not using TLS or the +ssl buffer when we are. Instead we take a FILE* parameter and check to see if +that is smtp_out; if so, smtp_printf() with TLS support, otherwise regular +fprintf(). + +Arguments: + f the candidate FILE* to write to + format format string + ... optional arguments + +Returns: + nothing +*/ + +static void PRINTF_FUNCTION(2,3) +respond_printf(FILE *f, const char *format, ...) +{ +va_list ap; + +va_start(ap, format); +if (smtp_out && (f == smtp_out)) + smtp_vprintf(format, FALSE, ap); +else + vfprintf(f, format, ap); +va_end(ap); +} + + + +/************************************************* +* Verify an email address * +*************************************************/ + +/* This function is used both for verification (-bv and at other times) and +address testing (-bt), which is indicated by address_test_mode being set. + +Arguments: + vaddr contains the address to verify; the next field in this block + must be NULL + f if not NULL, write the result to this file + options various option bits: + vopt_fake_sender => this sender verify is not for the real + sender (it was verify=sender=xxxx or an address from a + header line) - rewriting must not change sender_address + vopt_is_recipient => this is a recipient address, otherwise + it's a sender address - this affects qualification and + rewriting and messages from callouts + vopt_qualify => qualify an unqualified address; else error + vopt_expn => called from SMTP EXPN command + vopt_success_on_redirect => when a new address is generated + the verification instantly succeeds + + These ones are used by do_callout() -- the options variable + is passed to it. + + vopt_callout_fullpm => if postmaster check, do full one + vopt_callout_no_cache => don't use callout cache + vopt_callout_random => do the "random" thing + vopt_callout_recipsender => use real sender for recipient + vopt_callout_recippmaster => use postmaster for recipient + + callout if > 0, specifies that callout is required, and gives timeout + for individual commands + callout_overall if > 0, gives overall timeout for the callout function; + if < 0, a default is used (see do_callout()) + callout_connect the connection timeout for callouts + se_mailfrom when callout is requested to verify a sender, use this + in MAIL FROM; NULL => "" + pm_mailfrom when callout is requested, if non-NULL, do the postmaster + thing and use this as the sender address (may be "") + + routed if not NULL, set TRUE if routing succeeded, so we can + distinguish between routing failed and callout failed + +Returns: OK address verified + FAIL address failed to verify + DEFER can't tell at present +*/ + +int +verify_address(address_item * vaddr, FILE * fp, int options, int callout, + int callout_overall, int callout_connect, uschar * se_mailfrom, + uschar *pm_mailfrom, BOOL *routed) +{ +BOOL allok = TRUE; +BOOL full_info = fp ? debug_selector != 0 : FALSE; +BOOL expn = (options & vopt_expn) != 0; +BOOL success_on_redirect = (options & vopt_success_on_redirect) != 0; +int i; +int yield = OK; +int verify_type = expn? v_expn : + f.address_test_mode? v_none : + options & vopt_is_recipient? v_recipient : v_sender; +address_item *addr_list; +address_item *addr_new = NULL; +address_item *addr_remote = NULL; +address_item *addr_local = NULL; +address_item *addr_succeed = NULL; +uschar **failure_ptr = options & vopt_is_recipient + ? &recipient_verify_failure : &sender_verify_failure; +uschar *ko_prefix, *cr; +uschar *address = vaddr->address; +uschar *save_sender; +uschar null_sender[] = { 0 }; /* Ensure writeable memory */ + +/* Clear, just in case */ + +*failure_ptr = NULL; + +/* Set up a prefix and suffix for error message which allow us to use the same +output statements both in EXPN mode (where an SMTP response is needed) and when +debugging with an output file. */ + +if (expn) + { + ko_prefix = US"553 "; + cr = US"\r"; + } +else ko_prefix = cr = US""; + +/* Add qualify domain if permitted; otherwise an unqualified address fails. */ + +if (parse_find_at(address) == NULL) + { + if (!(options & vopt_qualify)) + { + if (fp) + respond_printf(fp, "%sA domain is required for \"%s\"%s\n", + ko_prefix, address, cr); + *failure_ptr = US"qualify"; + return FAIL; + } + address = rewrite_address_qualify(address, options & vopt_is_recipient); + } + +DEBUG(D_verify) + { + debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); + debug_printf("%s %s\n", f.address_test_mode? "Testing" : "Verifying", address); + } + +/* Rewrite and report on it. Clear the domain and local part caches - these +may have been set by domains and local part tests during an ACL. */ + +if (global_rewrite_rules) + { + uschar *old = address; + address = rewrite_address(address, options & vopt_is_recipient, FALSE, + global_rewrite_rules, rewrite_existflags); + if (address != old) + { + for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->localpart_cache[i] = 0; + for (i = 0; i < (MAX_NAMED_LIST * 2)/32; i++) vaddr->domain_cache[i] = 0; + if (fp && !expn) fprintf(fp, "Address rewritten as: %s\n", address); + } + } + +/* If this is the real sender address, we must update sender_address at +this point, because it may be referred to in the routers. */ + +if (!(options & (vopt_fake_sender|vopt_is_recipient))) + sender_address = address; + +/* If the address was rewritten to <> no verification can be done, and we have +to return OK. This rewriting is permitted only for sender addresses; for other +addresses, such rewriting fails. */ + +if (!address[0]) return OK; + +/* Flip the legacy TLS-related variables over to the outbound set in case +they're used in the context of a transport used by verification. Reset them +at exit from this routine (so no returns allowed from here on). */ + +tls_modify_variables(&tls_out); + +/* Save a copy of the sender address for re-instating if we change it to <> +while verifying a sender address (a nice bit of self-reference there). */ + +save_sender = sender_address; + +/* Observability variable for router/transport use */ + +verify_mode = options & vopt_is_recipient ? US"R" : US"S"; + +/* Update the address structure with the possibly qualified and rewritten +address. Set it up as the starting address on the chain of new addresses. */ + +vaddr->address = address; +addr_new = vaddr; + +/* We need a loop, because an address can generate new addresses. We must also +cope with generated pipes and files at the top level. (See also the code and +comment in deliver.c.) However, it is usually the case that the router for +user's .forward files has its verify flag turned off. + +If an address generates more than one child, the loop is used only when +full_info is set, and this can only be set locally. Remote enquiries just get +information about the top level address, not anything that it generated. */ + +while (addr_new) + { + int rc; + address_item *addr = addr_new; + + addr_new = addr->next; + addr->next = NULL; + + DEBUG(D_verify) + { + debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n"); + debug_printf("Considering %s\n", addr->address); + } + + /* Handle generated pipe, file or reply addresses. We don't get these + when handling EXPN, as it does only one level of expansion. */ + + if (testflag(addr, af_pfr)) + { + allok = FALSE; + if (fp) + { + BOOL allow; + + if (addr->address[0] == '>') + { + allow = testflag(addr, af_allow_reply); + fprintf(fp, "%s -> mail %s", addr->parent->address, addr->address + 1); + } + else + { + allow = addr->address[0] == '|' + ? testflag(addr, af_allow_pipe) : testflag(addr, af_allow_file); + fprintf(fp, "%s -> %s", addr->parent->address, addr->address); + } + + if (addr->basic_errno == ERRNO_BADTRANSPORT) + fprintf(fp, "\n*** Error in setting up pipe, file, or autoreply:\n" + "%s\n", addr->message); + else if (allow) + fprintf(fp, "\n transport = %s\n", addr->transport->name); + else + fprintf(fp, " *** forbidden ***\n"); + } + continue; + } + + /* Just in case some router parameter refers to it. */ + + return_path = addr->prop.errors_address + ? addr->prop.errors_address : sender_address; + + /* Split the address into domain and local part, handling the %-hack if + necessary, and then route it. While routing a sender address, set + $sender_address to <> because that is what it will be if we were trying to + send a bounce to the sender. */ + + if (routed) *routed = FALSE; + if ((rc = deliver_split_address(addr)) == OK) + { + if (!(options & vopt_is_recipient)) sender_address = null_sender; + rc = route_address(addr, &addr_local, &addr_remote, &addr_new, + &addr_succeed, verify_type); + sender_address = save_sender; /* Put back the real sender */ + } + + /* If routing an address succeeded, set the flag that remembers, for use when + an ACL cached a sender verify (in case a callout fails). Then if routing set + up a list of hosts or the transport has a host list, and the callout option + is set, and we aren't in a host checking run, do the callout verification, + and set another flag that notes that a callout happened. */ + + if (rc == OK) + { + if (routed) *routed = TRUE; + if (callout > 0) + { + transport_instance * tp; + host_item * host_list = addr->host_list; + + /* Make up some data for use in the case where there is no remote + transport. */ + + transport_feedback tf = { + .interface = NULL, /* interface (=> any) */ + .port = US"smtp", + .protocol = US"smtp", + .hosts = NULL, + .helo_data = US"$smtp_active_hostname", + .hosts_override = FALSE, + .hosts_randomize = FALSE, + .gethostbyname = FALSE, + .qualify_single = TRUE, + .search_parents = FALSE + }; + + /* If verification yielded a remote transport, we want to use that + transport's options, so as to mimic what would happen if we were really + sending a message to this address. */ + + if ((tp = addr->transport) && !tp->info->local) + { + (void)(tp->setup)(tp, addr, &tf, 0, 0, NULL); + + /* If the transport has hosts and the router does not, or if the + transport is configured to override the router's hosts, we must build a + host list of the transport's hosts, and find the IP addresses */ + + if (tf.hosts && (!host_list || tf.hosts_override)) + { + uschar *s; + const uschar *save_deliver_domain = deliver_domain; + uschar *save_deliver_localpart = deliver_localpart; + + host_list = NULL; /* Ignore the router's hosts */ + + deliver_domain = addr->domain; + deliver_localpart = addr->local_part; + s = expand_string(tf.hosts); + deliver_domain = save_deliver_domain; + deliver_localpart = save_deliver_localpart; + + if (!s) + { + log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand list of hosts " + "\"%s\" in %s transport for callout: %s", tf.hosts, + tp->name, expand_string_message); + } + else + { + int flags; + host_item *host, *nexthost; + host_build_hostlist(&host_list, s, tf.hosts_randomize); + + /* Just ignore failures to find a host address. If we don't manage + to find any addresses, the callout will defer. Note that more than + one address may be found for a single host, which will result in + additional host items being inserted into the chain. Hence we must + save the next host first. */ + + flags = HOST_FIND_BY_A | HOST_FIND_BY_AAAA; + if (tf.qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE; + if (tf.search_parents) flags |= HOST_FIND_SEARCH_PARENTS; + + for (host = host_list; host; host = nexthost) + { + nexthost = host->next; + if (tf.gethostbyname || + string_is_ip_address(host->name, NULL) != 0) + (void)host_find_byname(host, NULL, flags, NULL, TRUE); + else + { + const dnssec_domains * dsp = NULL; + if (Ustrcmp(tp->driver_name, "smtp") == 0) + { + smtp_transport_options_block * ob = + (smtp_transport_options_block *) tp->options_block; + dsp = &ob->dnssec; + } + + (void) host_find_bydns(host, NULL, flags, NULL, NULL, NULL, + dsp, NULL, NULL); + } + } + } + } + } + + /* Can only do a callout if we have at least one host! If the callout + fails, it will have set ${sender,recipient}_verify_failure. */ + + if (host_list) + { + HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n"); + if (host_checking && !f.host_checking_callout) + { + HDEBUG(D_verify) + debug_printf("... callout omitted by default when host testing\n" + "(Use -bhc if you want the callouts to happen.)\n"); + } + else + { +#ifdef SUPPORT_TLS + deliver_set_expansions(addr); +#endif + rc = do_callout(addr, host_list, &tf, callout, callout_overall, + callout_connect, options, se_mailfrom, pm_mailfrom); +#ifdef SUPPORT_TLS + deliver_set_expansions(NULL); +#endif + } + } + else + { + HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor " + "transport provided a host list, or transport is not smtp\n"); + } + } + } + + /* Otherwise, any failure is a routing failure */ + + else *failure_ptr = US"route"; + + /* A router may return REROUTED if it has set up a child address as a result + of a change of domain name (typically from widening). In this case we always + want to continue to verify the new child. */ + + if (rc == REROUTED) continue; + + /* Handle hard failures */ + + if (rc == FAIL) + { + allok = FALSE; + if (fp) + { + address_item *p = addr->parent; + + respond_printf(fp, "%s%s %s", ko_prefix, + full_info ? addr->address : address, + f.address_test_mode ? "is undeliverable" : "failed to verify"); + if (!expn && f.admin_user) + { + if (addr->basic_errno > 0) + respond_printf(fp, ": %s", strerror(addr->basic_errno)); + if (addr->message) + respond_printf(fp, ": %s", addr->message); + } + + /* Show parents iff doing full info */ + + if (full_info) while (p) + { + respond_printf(fp, "%s\n <-- %s", cr, p->address); + p = p->parent; + } + respond_printf(fp, "%s\n", cr); + } + cancel_cutthrough_connection(TRUE, US"routing hard fail"); + + if (!full_info) + { + yield = copy_error(vaddr, addr, FAIL); + goto out; + } + yield = FAIL; + } + + /* Soft failure */ + + else if (rc == DEFER) + { + allok = FALSE; + if (fp) + { + address_item *p = addr->parent; + respond_printf(fp, "%s%s cannot be resolved at this time", ko_prefix, + full_info? addr->address : address); + if (!expn && f.admin_user) + { + if (addr->basic_errno > 0) + respond_printf(fp, ": %s", strerror(addr->basic_errno)); + if (addr->message) + respond_printf(fp, ": %s", addr->message); + else if (addr->basic_errno <= 0) + respond_printf(fp, ": unknown error"); + } + + /* Show parents iff doing full info */ + + if (full_info) while (p) + { + respond_printf(fp, "%s\n <-- %s", cr, p->address); + p = p->parent; + } + respond_printf(fp, "%s\n", cr); + } + cancel_cutthrough_connection(TRUE, US"routing soft fail"); + + if (!full_info) + { + yield = copy_error(vaddr, addr, DEFER); + goto out; + } + if (yield == OK) yield = DEFER; + } + + /* If we are handling EXPN, we do not want to continue to route beyond + the top level (whose address is in "address"). */ + + else if (expn) + { + uschar *ok_prefix = US"250-"; + + if (!addr_new) + if (!addr_local && !addr_remote) + respond_printf(fp, "250 mail to <%s> is discarded\r\n", address); + else + respond_printf(fp, "250 <%s>\r\n", address); + + else do + { + address_item *addr2 = addr_new; + addr_new = addr2->next; + if (!addr_new) ok_prefix = US"250 "; + respond_printf(fp, "%s<%s>\r\n", ok_prefix, addr2->address); + } while (addr_new); + yield = OK; + goto out; + } + + /* Successful routing other than EXPN. */ + + else + { + /* Handle successful routing when short info wanted. Otherwise continue for + other (generated) addresses. Short info is the operational case. Full info + can be requested only when debug_selector != 0 and a file is supplied. + + There is a conflict between the use of aliasing as an alternate email + address, and as a sort of mailing list. If an alias turns the incoming + address into just one address (e.g. J.Caesar->jc44) you may well want to + carry on verifying the generated address to ensure it is valid when + checking incoming mail. If aliasing generates multiple addresses, you + probably don't want to do this. Exim therefore treats the generation of + just a single new address as a special case, and continues on to verify the + generated address. */ + + if ( !full_info /* Stop if short info wanted AND */ + && ( ( !addr_new /* No new address OR */ + || addr_new->next /* More than one new address OR */ + || testflag(addr_new, af_pfr) /* New address is pfr */ + ) + || /* OR */ + ( addr_new /* At least one new address AND */ + && success_on_redirect /* success_on_redirect is set */ + ) ) + ) + { + if (fp) fprintf(fp, "%s %s\n", + address, f.address_test_mode ? "is deliverable" : "verified"); + + /* If we have carried on to verify a child address, we want the value + of $address_data to be that of the child */ + + vaddr->prop.address_data = addr->prop.address_data; + + /* If stopped because more than one new address, cannot cutthrough */ + + if (addr_new && addr_new->next) + cancel_cutthrough_connection(TRUE, US"multiple addresses from routing"); + + yield = OK; + goto out; + } + } + } /* Loop for generated addresses */ + +/* Display the full results of the successful routing, including any generated +addresses. Control gets here only when full_info is set, which requires fp not +to be NULL, and this occurs only when a top-level verify is called with the +debugging switch on. + +If there are no local and no remote addresses, and there were no pipes, files, +or autoreplies, and there were no errors or deferments, the message is to be +discarded, usually because of the use of :blackhole: in an alias file. */ + +if (allok && !addr_local && !addr_remote) + { + fprintf(fp, "mail to %s is discarded\n", address); + goto out; + } + +for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++) + while (addr_list) + { + address_item *addr = addr_list; + address_item *p = addr->parent; + transport_instance * tp = addr->transport; + + addr_list = addr->next; + + fprintf(fp, "%s", CS addr->address); +#ifdef EXPERIMENTAL_SRS + if(addr->prop.srs_sender) + fprintf(fp, " [srs = %s]", addr->prop.srs_sender); +#endif + + /* If the address is a duplicate, show something about it. */ + + if (!testflag(addr, af_pfr)) + { + tree_node *tnode; + if ((tnode = tree_search(tree_duplicates, addr->unique))) + fprintf(fp, " [duplicate, would not be delivered]"); + else tree_add_duplicate(addr->unique, addr); + } + + /* Now show its parents */ + + for (p = addr->parent; p; p = p->parent) + fprintf(fp, "\n <-- %s", p->address); + fprintf(fp, "\n "); + + /* Show router, and transport */ + + fprintf(fp, "router = %s, transport = %s\n", + addr->router->name, tp ? tp->name : US"unset"); + + /* Show any hosts that are set up by a router unless the transport + is going to override them; fiddle a bit to get a nice format. */ + + if (addr->host_list && tp && !tp->overrides_hosts) + { + host_item *h; + int maxlen = 0; + int maxaddlen = 0; + for (h = addr->host_list; h; h = h->next) + { /* get max lengths of host names, addrs */ + int len = Ustrlen(h->name); + if (len > maxlen) maxlen = len; + len = h->address ? Ustrlen(h->address) : 7; + if (len > maxaddlen) maxaddlen = len; + } + for (h = addr->host_list; h; h = h->next) + { + fprintf(fp, " host %-*s ", maxlen, h->name); + + if (h->address) + fprintf(fp, "[%s%-*c", h->address, maxaddlen+1 - Ustrlen(h->address), ']'); + else if (tp->info->local) + fprintf(fp, " %-*s ", maxaddlen, ""); /* Omit [unknown] for local */ + else + fprintf(fp, "[%s%-*c", "unknown", maxaddlen+1 - 7, ']'); + + if (h->mx >= 0) fprintf(fp, " MX=%d", h->mx); + if (h->port != PORT_NONE) fprintf(fp, " port=%d", h->port); + if (f.running_in_test_harness && h->dnssec == DS_YES) fputs(" AD", fp); + if (h->status == hstatus_unusable) fputs(" ** unusable **", fp); + fputc('\n', fp); + } + } + } + +/* Yield will be DEFER or FAIL if any one address has, only for full_info (which is +the -bv or -bt case). */ + +out: +verify_mode = NULL; +tls_modify_variables(&tls_in); + +return yield; +} + + + + +/************************************************* +* Check headers for syntax errors * +*************************************************/ + +/* This function checks those header lines that contain addresses, and verifies +that all the addresses therein are 5322-syntactially correct. + +Arguments: + msgptr where to put an error message + +Returns: OK + FAIL +*/ + +int +verify_check_headers(uschar **msgptr) +{ +header_line *h; +uschar *colon, *s; +int yield = OK; + +for (h = header_list; h && yield == OK; h = h->next) + { + if (h->type != htype_from && + h->type != htype_reply_to && + h->type != htype_sender && + h->type != htype_to && + h->type != htype_cc && + h->type != htype_bcc) + continue; + + colon = Ustrchr(h->text, ':'); + s = colon + 1; + while (isspace(*s)) s++; + + /* Loop for multiple addresses in the header, enabling group syntax. Note + that we have to reset this after the header has been scanned. */ + + f.parse_allow_group = TRUE; + + while (*s) + { + uschar *ss = parse_find_address_end(s, FALSE); + uschar *recipient, *errmess; + int terminator = *ss; + int start, end, domain; + + /* Temporarily terminate the string at this point, and extract the + operative address within, allowing group syntax. */ + + *ss = 0; + recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE); + *ss = terminator; + + /* Permit an unqualified address only if the message is local, or if the + sending host is configured to be permitted to send them. */ + + if (recipient && !domain) + { + if (h->type == htype_from || h->type == htype_sender) + { + if (!f.allow_unqualified_sender) recipient = NULL; + } + else + { + if (!f.allow_unqualified_recipient) recipient = NULL; + } + if (recipient == NULL) errmess = US"unqualified address not permitted"; + } + + /* It's an error if no address could be extracted, except for the special + case of an empty address. */ + + if (!recipient && Ustrcmp(errmess, "empty address") != 0) + { + uschar *verb = US"is"; + uschar *t = ss; + uschar *tt = colon; + int len; + + /* Arrange not to include any white space at the end in the + error message or the header name. */ + + while (t > s && isspace(t[-1])) t--; + while (tt > h->text && isspace(tt[-1])) tt--; + + /* Add the address that failed to the error message, since in a + header with very many addresses it is sometimes hard to spot + which one is at fault. However, limit the amount of address to + quote - cases have been seen where, for example, a missing double + quote in a humungous To: header creates an "address" that is longer + than string_sprintf can handle. */ + + len = t - s; + if (len > 1024) + { + len = 1024; + verb = US"begins"; + } + + /* deconst cast ok as we're passing a non-const to string_printing() */ + *msgptr = US string_printing( + string_sprintf("%s: failing address in \"%.*s:\" header %s: %.*s", + errmess, (int)(tt - h->text), h->text, verb, len, s)); + + yield = FAIL; + break; /* Out of address loop */ + } + + /* Advance to the next address */ + + s = ss + (terminator ? 1 : 0); + while (isspace(*s)) s++; + } /* Next address */ + + f.parse_allow_group = FALSE; + f.parse_found_group = FALSE; + } /* Next header unless yield has been set FALSE */ + +return yield; +} + + +/************************************************* +* Check header names for 8-bit characters * +*************************************************/ + +/* This function checks for invalid characters in header names. See +RFC 5322, 2.2. and RFC 6532, 3. + +Arguments: + msgptr where to put an error message + +Returns: OK + FAIL +*/ + +int +verify_check_header_names_ascii(uschar **msgptr) +{ +header_line *h; +uschar *colon, *s; + +for (h = header_list; h; h = h->next) + { + colon = Ustrchr(h->text, ':'); + for(s = h->text; s < colon; s++) + if ((*s < 33) || (*s > 126)) + { + *msgptr = string_sprintf("Invalid character in header \"%.*s\" found", + colon - h->text, h->text); + return FAIL; + } + } +return OK; +} + +/************************************************* +* Check for blind recipients * +*************************************************/ + +/* This function checks that every (envelope) recipient is mentioned in either +the To: or Cc: header lines, thus detecting blind carbon copies. + +There are two ways of scanning that could be used: either scan the header lines +and tick off the recipients, or scan the recipients and check the header lines. +The original proposed patch did the former, but I have chosen to do the latter, +because (a) it requires no memory and (b) will use fewer resources when there +are many addresses in To: and/or Cc: and only one or two envelope recipients. + +Arguments: none +Returns: OK if there are no blind recipients + FAIL if there is at least one blind recipient +*/ + +int +verify_check_notblind(void) +{ +int i; +for (i = 0; i < recipients_count; i++) + { + header_line *h; + BOOL found = FALSE; + uschar *address = recipients_list[i].address; + + for (h = header_list; !found && h != NULL; h = h->next) + { + uschar *colon, *s; + + if (h->type != htype_to && h->type != htype_cc) continue; + + colon = Ustrchr(h->text, ':'); + s = colon + 1; + while (isspace(*s)) s++; + + /* Loop for multiple addresses in the header, enabling group syntax. Note + that we have to reset this after the header has been scanned. */ + + f.parse_allow_group = TRUE; + + while (*s != 0) + { + uschar *ss = parse_find_address_end(s, FALSE); + uschar *recipient,*errmess; + int terminator = *ss; + int start, end, domain; + + /* Temporarily terminate the string at this point, and extract the + operative address within, allowing group syntax. */ + + *ss = 0; + recipient = parse_extract_address(s,&errmess,&start,&end,&domain,FALSE); + *ss = terminator; + + /* If we found a valid recipient that has a domain, compare it with the + envelope recipient. Local parts are compared case-sensitively, domains + case-insensitively. By comparing from the start with length "domain", we + include the "@" at the end, which ensures that we are comparing the whole + local part of each address. */ + + if (recipient != NULL && domain != 0) + { + found = Ustrncmp(recipient, address, domain) == 0 && + strcmpic(recipient + domain, address + domain) == 0; + if (found) break; + } + + /* Advance to the next address */ + + s = ss + (terminator? 1:0); + while (isspace(*s)) s++; + } /* Next address */ + + f.parse_allow_group = FALSE; + f.parse_found_group = FALSE; + } /* Next header (if found is false) */ + + if (!found) return FAIL; + } /* Next recipient */ + +return OK; +} + + + +/************************************************* +* Find if verified sender * +*************************************************/ + +/* Usually, just a single address is verified as the sender of the message. +However, Exim can be made to verify other addresses as well (often related in +some way), and this is useful in some environments. There may therefore be a +chain of such addresses that have previously been tested. This function finds +whether a given address is on the chain. + +Arguments: the address to be verified +Returns: pointer to an address item, or NULL +*/ + +address_item * +verify_checked_sender(uschar *sender) +{ +address_item *addr; +for (addr = sender_verified_list; addr != NULL; addr = addr->next) + if (Ustrcmp(sender, addr->address) == 0) break; +return addr; +} + + + + + +/************************************************* +* Get valid header address * +*************************************************/ + +/* Scan the originator headers of the message, looking for an address that +verifies successfully. RFC 822 says: + + o The "Sender" field mailbox should be sent notices of + any problems in transport or delivery of the original + messages. If there is no "Sender" field, then the + "From" field mailbox should be used. + + o If the "Reply-To" field exists, then the reply should + go to the addresses indicated in that field and not to + the address(es) indicated in the "From" field. + +So we check a Sender field if there is one, else a Reply_to field, else a From +field. As some strange messages may have more than one of these fields, +especially if they are resent- fields, check all of them if there is more than +one. + +Arguments: + user_msgptr points to where to put a user error message + log_msgptr points to where to put a log error message + callout timeout for callout check (passed to verify_address()) + callout_overall overall callout timeout (ditto) + callout_connect connect callout timeout (ditto) + se_mailfrom mailfrom for verify; NULL => "" + pm_mailfrom sender for pm callout check (passed to verify_address()) + options callout options (passed to verify_address()) + verrno where to put the address basic_errno + +If log_msgptr is set to something without setting user_msgptr, the caller +normally uses log_msgptr for both things. + +Returns: result of the verification attempt: OK, FAIL, or DEFER; + FAIL is given if no appropriate headers are found +*/ + +int +verify_check_header_address(uschar **user_msgptr, uschar **log_msgptr, + int callout, int callout_overall, int callout_connect, uschar *se_mailfrom, + uschar *pm_mailfrom, int options, int *verrno) +{ +static int header_types[] = { htype_sender, htype_reply_to, htype_from }; +BOOL done = FALSE; +int yield = FAIL; +int i; + +for (i = 0; i < 3 && !done; i++) + { + header_line *h; + for (h = header_list; h != NULL && !done; h = h->next) + { + int terminator, new_ok; + uschar *s, *ss, *endname; + + if (h->type != header_types[i]) continue; + s = endname = Ustrchr(h->text, ':') + 1; + + /* Scan the addresses in the header, enabling group syntax. Note that we + have to reset this after the header has been scanned. */ + + f.parse_allow_group = TRUE; + + while (*s != 0) + { + address_item *vaddr; + + while (isspace(*s) || *s == ',') s++; + if (*s == 0) break; /* End of header */ + + ss = parse_find_address_end(s, FALSE); + + /* The terminator is a comma or end of header, but there may be white + space preceding it (including newline for the last address). Move back + past any white space so we can check against any cached envelope sender + address verifications. */ + + while (isspace(ss[-1])) ss--; + terminator = *ss; + *ss = 0; + + HDEBUG(D_verify) debug_printf("verifying %.*s header address %s\n", + (int)(endname - h->text), h->text, s); + + /* See if we have already verified this address as an envelope sender, + and if so, use the previous answer. */ + + vaddr = verify_checked_sender(s); + + if (vaddr != NULL && /* Previously checked */ + (callout <= 0 || /* No callout needed; OR */ + vaddr->special_action > 256)) /* Callout was done */ + { + new_ok = vaddr->special_action & 255; + HDEBUG(D_verify) debug_printf("previously checked as envelope sender\n"); + *ss = terminator; /* Restore shortened string */ + } + + /* Otherwise we run the verification now. We must restore the shortened + string before running the verification, so the headers are correct, in + case there is any rewriting. */ + + else + { + int start, end, domain; + uschar *address = parse_extract_address(s, log_msgptr, &start, &end, + &domain, FALSE); + + *ss = terminator; + + /* If we found an empty address, just carry on with the next one, but + kill the message. */ + + if (address == NULL && Ustrcmp(*log_msgptr, "empty address") == 0) + { + *log_msgptr = NULL; + s = ss; + continue; + } + + /* If verification failed because of a syntax error, fail this + function, and ensure that the failing address gets added to the error + message. */ + + if (address == NULL) + { + new_ok = FAIL; + while (ss > s && isspace(ss[-1])) ss--; + *log_msgptr = string_sprintf("syntax error in '%.*s' header when " + "scanning for sender: %s in \"%.*s\"", + (int)(endname - h->text), h->text, *log_msgptr, (int)(ss - s), s); + yield = FAIL; + done = TRUE; + break; + } + + /* Else go ahead with the sender verification. But it isn't *the* + sender of the message, so set vopt_fake_sender to stop sender_address + being replaced after rewriting or qualification. */ + + else + { + vaddr = deliver_make_addr(address, FALSE); + new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender, + callout, callout_overall, callout_connect, se_mailfrom, + pm_mailfrom, NULL); + } + } + + /* We now have the result, either newly found, or cached. If we are + giving out error details, set a specific user error. This means that the + last of these will be returned to the user if all three fail. We do not + set a log message - the generic one below will be used. */ + + if (new_ok != OK) + { + *verrno = vaddr->basic_errno; + if (smtp_return_error_details) + *user_msgptr = string_sprintf("Rejected after DATA: " + "could not verify \"%.*s\" header address\n%s: %s", + (int)(endname - h->text), h->text, vaddr->address, vaddr->message); + } + + /* Success or defer */ + + if (new_ok == OK) + { + yield = OK; + done = TRUE; + break; + } + + if (new_ok == DEFER) yield = DEFER; + + /* Move on to any more addresses in the header */ + + s = ss; + } /* Next address */ + + f.parse_allow_group = FALSE; + f.parse_found_group = FALSE; + } /* Next header, unless done */ + } /* Next header type unless done */ + +if (yield == FAIL && *log_msgptr == NULL) + *log_msgptr = US"there is no valid sender in any header line"; + +if (yield == DEFER && *log_msgptr == NULL) + *log_msgptr = US"all attempts to verify a sender in a header line deferred"; + +return yield; +} + + + + +/************************************************* +* Get RFC 1413 identification * +*************************************************/ + +/* Attempt to get an id from the sending machine via the RFC 1413 protocol. If +the timeout is set to zero, then the query is not done. There may also be lists +of hosts and nets which are exempt. To guard against malefactors sending +non-printing characters which could, for example, disrupt a message's headers, +make sure the string consists of printing characters only. + +Argument: + port the port to connect to; usually this is IDENT_PORT (113), but when + running in the test harness with -bh a different value is used. + +Returns: nothing + +Side effect: any received ident value is put in sender_ident (NULL otherwise) +*/ + +void +verify_get_ident(int port) +{ +client_conn_ctx ident_conn_ctx = {0}; +int host_af, qlen; +int received_sender_port, received_interface_port, n; +uschar *p; +blob early_data; +uschar buffer[2048]; + +/* Default is no ident. Check whether we want to do an ident check for this +host. */ + +sender_ident = NULL; +if (rfc1413_query_timeout <= 0 || verify_check_host(&rfc1413_hosts) != OK) + return; + +DEBUG(D_ident) debug_printf("doing ident callback\n"); + +/* Set up a connection to the ident port of the remote host. Bind the local end +to the incoming interface address. If the sender host address is an IPv6 +address, the incoming interface address will also be IPv6. */ + +host_af = Ustrchr(sender_host_address, ':') == NULL ? AF_INET : AF_INET6; +if ((ident_conn_ctx.sock = ip_socket(SOCK_STREAM, host_af)) < 0) return; + +if (ip_bind(ident_conn_ctx.sock, host_af, interface_address, 0) < 0) + { + DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n", + strerror(errno)); + goto END_OFF; + } + +/* Construct and send the query. */ + +qlen = snprintf(CS buffer, sizeof(buffer), "%d , %d\r\n", + sender_host_port, interface_port); +early_data.data = buffer; +early_data.len = qlen; + +/*XXX we trust that the query is idempotent */ +if (ip_connect(ident_conn_ctx.sock, host_af, sender_host_address, port, + rfc1413_query_timeout, &early_data) < 0) + { + if (errno == ETIMEDOUT && LOGGING(ident_timeout)) + log_write(0, LOG_MAIN, "ident connection to %s timed out", + sender_host_address); + else + DEBUG(D_ident) debug_printf("ident connection to %s failed: %s\n", + sender_host_address, strerror(errno)); + goto END_OFF; + } + +/* Read a response line. We put it into the rest of the buffer, using several +recv() calls if necessary. */ + +p = buffer + qlen; + +for (;;) + { + uschar *pp; + int count; + int size = sizeof(buffer) - (p - buffer); + + if (size <= 0) goto END_OFF; /* Buffer filled without seeing \n. */ + count = ip_recv(&ident_conn_ctx, p, size, rfc1413_query_timeout); + if (count <= 0) goto END_OFF; /* Read error or EOF */ + + /* Scan what we just read, to see if we have reached the terminating \r\n. Be + generous, and accept a plain \n terminator as well. The only illegal + character is 0. */ + + for (pp = p; pp < p + count; pp++) + { + if (*pp == 0) goto END_OFF; /* Zero octet not allowed */ + if (*pp == '\n') + { + if (pp[-1] == '\r') pp--; + *pp = 0; + goto GOT_DATA; /* Break out of both loops */ + } + } + + /* Reached the end of the data without finding \n. Let the loop continue to + read some more, if there is room. */ + + p = pp; + } + +GOT_DATA: + +/* We have received a line of data. Check it carefully. It must start with the +same two port numbers that we sent, followed by data as defined by the RFC. For +example, + + 12345 , 25 : USERID : UNIX :root + +However, the amount of white space may be different to what we sent. In the +"osname" field there may be several sub-fields, comma separated. The data we +actually want to save follows the third colon. Some systems put leading spaces +in it - we discard those. */ + +if (sscanf(CS buffer + qlen, "%d , %d%n", &received_sender_port, + &received_interface_port, &n) != 2 || + received_sender_port != sender_host_port || + received_interface_port != interface_port) + goto END_OFF; + +p = buffer + qlen + n; +while(isspace(*p)) p++; +if (*p++ != ':') goto END_OFF; +while(isspace(*p)) p++; +if (Ustrncmp(p, "USERID", 6) != 0) goto END_OFF; +p += 6; +while(isspace(*p)) p++; +if (*p++ != ':') goto END_OFF; +while (*p != 0 && *p != ':') p++; +if (*p++ == 0) goto END_OFF; +while(isspace(*p)) p++; +if (*p == 0) goto END_OFF; + +/* The rest of the line is the data we want. We turn it into printing +characters when we save it, so that it cannot mess up the format of any logging +or Received: lines into which it gets inserted. We keep a maximum of 127 +characters. The deconst cast is ok as we fed a nonconst to string_printing() */ + +sender_ident = US string_printing(string_copyn(p, 127)); +DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident); + +END_OFF: +(void)close(ident_conn_ctx.sock); +return; +} + + + + +/************************************************* +* Match host to a single host-list item * +*************************************************/ + +/* This function compares a host (name or address) against a single item +from a host list. The host name gets looked up if it is needed and is not +already known. The function is called from verify_check_this_host() via +match_check_list(), which is why most of its arguments are in a single block. + +Arguments: + arg the argument block (see below) + ss the host-list item + valueptr where to pass back looked up data, or NULL + error for error message when returning ERROR + +The block contains: + host_name (a) the host name, or + (b) NULL, implying use sender_host_name and + sender_host_aliases, looking them up if required, or + (c) the empty string, meaning that only IP address matches + are permitted + host_address the host address + host_ipv4 the IPv4 address taken from an IPv6 one + +Returns: OK matched + FAIL did not match + DEFER lookup deferred + ERROR (a) failed to find the host name or IP address, or + (b) unknown lookup type specified, or + (c) host name encountered when only IP addresses are + being matched +*/ + +int +check_host(void *arg, const uschar *ss, const uschar **valueptr, uschar **error) +{ +check_host_block *cb = (check_host_block *)arg; +int mlen = -1; +int maskoffset; +BOOL iplookup = FALSE; +BOOL isquery = FALSE; +BOOL isiponly = cb->host_name != NULL && cb->host_name[0] == 0; +const uschar *t; +uschar *semicolon; +uschar **aliases; + +/* Optimize for the special case when the pattern is "*". */ + +if (*ss == '*' && ss[1] == 0) return OK; + +/* If the pattern is empty, it matches only in the case when there is no host - +this can occur in ACL checking for SMTP input using the -bs option. In this +situation, the host address is the empty string. */ + +if (cb->host_address[0] == 0) return (*ss == 0)? OK : FAIL; +if (*ss == 0) return FAIL; + +/* If the pattern is precisely "@" then match against the primary host name, +provided that host name matching is permitted; if it's "@[]" match against the +local host's IP addresses. */ + +if (*ss == '@') + { + if (ss[1] == 0) + { + if (isiponly) return ERROR; + ss = primary_hostname; + } + else if (Ustrcmp(ss, "@[]") == 0) + { + ip_address_item *ip; + for (ip = host_find_interfaces(); ip != NULL; ip = ip->next) + if (Ustrcmp(ip->address, cb->host_address) == 0) return OK; + return FAIL; + } + } + +/* If the pattern is an IP address, optionally followed by a bitmask count, do +a (possibly masked) comparison with the current IP address. */ + +if (string_is_ip_address(ss, &maskoffset) != 0) + return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL); + +/* The pattern is not an IP address. A common error that people make is to omit +one component of an IPv4 address, either by accident, or believing that, for +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, +which it isn't. (Those applications that do accept 1.2.3 as an IP address +interpret it as 1.2.0.3 because the final component becomes 16-bit - this is an +ancient specification.) To aid in debugging these cases, we give a specific +error if the pattern contains only digits and dots or contains a slash preceded +only by digits and dots (a slash at the start indicates a file name and of +course slashes may be present in lookups, but not preceded only by digits and +dots). */ + +for (t = ss; isdigit(*t) || *t == '.'; t++); +if (*t == 0 || (*t == '/' && t != ss)) + { + *error = US"malformed IPv4 address or address mask"; + return ERROR; + } + +/* See if there is a semicolon in the pattern */ + +semicolon = Ustrchr(ss, ';'); + +/* If we are doing an IP address only match, then all lookups must be IP +address lookups, even if there is no "net-". */ + +if (isiponly) + { + iplookup = semicolon != NULL; + } + +/* Otherwise, if the item is of the form net[n]-lookup;<file|query> then it is +a lookup on a masked IP network, in textual form. We obey this code even if we +have already set iplookup, so as to skip over the "net-" prefix and to set the +mask length. The net- stuff really only applies to single-key lookups where the +key is implicit. For query-style lookups the key is specified in the query. +From release 4.30, the use of net- for query style is no longer needed, but we +retain it for backward compatibility. */ + +if (Ustrncmp(ss, "net", 3) == 0 && semicolon != NULL) + { + mlen = 0; + for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0'; + if (mlen == 0 && t == ss+3) mlen = -1; /* No mask supplied */ + iplookup = (*t++ == '-'); + } +else t = ss; + +/* Do the IP address lookup if that is indeed what we have */ + +if (iplookup) + { + int insize; + int search_type; + int incoming[4]; + void *handle; + uschar *filename, *key, *result; + uschar buffer[64]; + + /* Find the search type */ + + search_type = search_findtype(t, semicolon - t); + + if (search_type < 0) log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s", + search_error_message); + + /* Adjust parameters for the type of lookup. For a query-style lookup, there + is no file name, and the "key" is just the query. For query-style with a file + name, we have to fish the file off the start of the query. For a single-key + lookup, the key is the current IP address, masked appropriately, and + reconverted to text form, with the mask appended. For IPv6 addresses, specify + dot separators instead of colons, except when the lookup type is "iplsearch". + */ + + if (mac_islookup(search_type, lookup_absfilequery)) + { + filename = semicolon + 1; + key = filename; + while (*key != 0 && !isspace(*key)) key++; + filename = string_copyn(filename, key - filename); + while (isspace(*key)) key++; + } + else if (mac_islookup(search_type, lookup_querystyle)) + { + filename = NULL; + key = semicolon + 1; + } + else /* Single-key style */ + { + int sep = (Ustrcmp(lookup_list[search_type]->name, "iplsearch") == 0)? + ':' : '.'; + insize = host_aton(cb->host_address, incoming); + host_mask(insize, incoming, mlen); + (void)host_nmtoa(insize, incoming, mlen, buffer, sep); + key = buffer; + filename = semicolon + 1; + } + + /* Now do the actual lookup; note that there is no search_close() because + of the caching arrangements. */ + + if (!(handle = search_open(filename, search_type, 0, NULL, NULL))) + log_write(0, LOG_MAIN|LOG_PANIC_DIE, "%s", search_error_message); + + result = search_find(handle, filename, key, -1, NULL, 0, 0, NULL); + if (valueptr) *valueptr = result; + return result ? OK : f.search_find_defer ? DEFER: FAIL; + } + +/* The pattern is not an IP address or network reference of any kind. That is, +it is a host name pattern. If this is an IP only match, there's an error in the +host list. */ + +if (isiponly) + { + *error = US"cannot match host name in match_ip list"; + return ERROR; + } + +/* Check the characters of the pattern to see if they comprise only letters, +digits, full stops, and hyphens (the constituents of domain names). Allow +underscores, as they are all too commonly found. Sigh. Also, if +allow_utf8_domains is set, allow top-bit characters. */ + +for (t = ss; *t != 0; t++) + if (!isalnum(*t) && *t != '.' && *t != '-' && *t != '_' && + (!allow_utf8_domains || *t < 128)) break; + +/* If the pattern is a complete domain name, with no fancy characters, look up +its IP address and match against that. Note that a multi-homed host will add +items to the chain. */ + +if (*t == 0) + { + int rc; + host_item h; + h.next = NULL; + h.name = ss; + h.address = NULL; + h.mx = MX_NONE; + + /* Using byname rather than bydns here means we cannot determine dnssec + status. On the other hand it is unclear how that could be either + propagated up or enforced. */ + + rc = host_find_byname(&h, NULL, HOST_FIND_QUALIFY_SINGLE, NULL, FALSE); + if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL) + { + host_item *hh; + for (hh = &h; hh != NULL; hh = hh->next) + { + if (host_is_in_net(hh->address, cb->host_address, 0)) return OK; + } + return FAIL; + } + if (rc == HOST_FIND_AGAIN) return DEFER; + *error = string_sprintf("failed to find IP address for %s", ss); + return ERROR; + } + +/* Almost all subsequent comparisons require the host name, and can be done +using the general string matching function. When this function is called for +outgoing hosts, the name is always given explicitly. If it is NULL, it means we +must use sender_host_name and its aliases, looking them up if necessary. */ + +if (cb->host_name != NULL) /* Explicit host name given */ + return match_check_string(cb->host_name, ss, -1, TRUE, TRUE, TRUE, + valueptr); + +/* Host name not given; in principle we need the sender host name and its +aliases. However, for query-style lookups, we do not need the name if the +query does not contain $sender_host_name. From release 4.23, a reference to +$sender_host_name causes it to be looked up, so we don't need to do the lookup +on spec. */ + +if ((semicolon = Ustrchr(ss, ';')) != NULL) + { + const uschar *affix; + int partial, affixlen, starflags, id; + + *semicolon = 0; + id = search_findtype_partial(ss, &partial, &affix, &affixlen, &starflags); + *semicolon=';'; + + if (id < 0) /* Unknown lookup type */ + { + log_write(0, LOG_MAIN|LOG_PANIC, "%s in host list item \"%s\"", + search_error_message, ss); + return DEFER; + } + isquery = mac_islookup(id, lookup_querystyle|lookup_absfilequery); + } + +if (isquery) + { + switch(match_check_string(US"", ss, -1, TRUE, TRUE, TRUE, valueptr)) + { + case OK: return OK; + case DEFER: return DEFER; + default: return FAIL; + } + } + +/* Not a query-style lookup; must ensure the host name is present, and then we +do a check on the name and all its aliases. */ + +if (!sender_host_name) + { + HDEBUG(D_host_lookup) + debug_printf("sender host name required, to match against %s\n", ss); + if (host_lookup_failed || host_name_lookup() != OK) + { + *error = string_sprintf("failed to find host name for %s", + sender_host_address);; + return ERROR; + } + host_build_sender_fullhost(); + } + +/* Match on the sender host name, using the general matching function */ + +switch(match_check_string(sender_host_name, ss, -1, TRUE, TRUE, TRUE, valueptr)) + { + case OK: return OK; + case DEFER: return DEFER; + } + +/* If there are aliases, try matching on them. */ + +aliases = sender_host_aliases; +while (*aliases) + switch(match_check_string(*aliases++, ss, -1, TRUE, TRUE, TRUE, valueptr)) + { + case OK: return OK; + case DEFER: return DEFER; + } +return FAIL; +} + + + + +/************************************************* +* Check a specific host matches a host list * +*************************************************/ + +/* This function is passed a host list containing items in a number of +different formats and the identity of a host. Its job is to determine whether +the given host is in the set of hosts defined by the list. The host name is +passed as a pointer so that it can be looked up if needed and not already +known. This is commonly the case when called from verify_check_host() to check +an incoming connection. When called from elsewhere the host name should usually +be set. + +This function is now just a front end to match_check_list(), which runs common +code for scanning a list. We pass it the check_host() function to perform a +single test. + +Arguments: + listptr pointer to the host list + cache_bits pointer to cache for named lists, or NULL + host_name the host name or NULL, implying use sender_host_name and + sender_host_aliases, looking them up if required + host_address the IP address + valueptr if not NULL, data from a lookup is passed back here + +Returns: OK if the host is in the defined set + FAIL if the host is not in the defined set, + DEFER if a data lookup deferred (not a host lookup) + +If the host name was needed in order to make a comparison, and could not be +determined from the IP address, the result is FAIL unless the item +"+allow_unknown" was met earlier in the list, in which case OK is returned. */ + +int +verify_check_this_host(const uschar **listptr, unsigned int *cache_bits, + const uschar *host_name, const uschar *host_address, const uschar **valueptr) +{ +int rc; +unsigned int *local_cache_bits = cache_bits; +const uschar *save_host_address = deliver_host_address; +check_host_block cb = { .host_name = host_name, .host_address = host_address }; + +if (valueptr) *valueptr = NULL; + +/* If the host address starts off ::ffff: it is an IPv6 address in +IPv4-compatible mode. Find the IPv4 part for checking against IPv4 +addresses. */ + +cb.host_ipv4 = Ustrncmp(host_address, "::ffff:", 7) == 0 + ? host_address + 7 : host_address; + +/* During the running of the check, put the IP address into $host_address. In +the case of calls from the smtp transport, it will already be there. However, +in other calls (e.g. when testing ignore_target_hosts), it won't. Just to be on +the safe side, any existing setting is preserved, though as I write this +(November 2004) I can't see any cases where it is actually needed. */ + +deliver_host_address = host_address; +rc = match_check_list( + listptr, /* the list */ + 0, /* separator character */ + &hostlist_anchor, /* anchor pointer */ + &local_cache_bits, /* cache pointer */ + check_host, /* function for testing */ + &cb, /* argument for function */ + MCL_HOST, /* type of check */ + (host_address == sender_host_address)? + US"host" : host_address, /* text for debugging */ + valueptr); /* where to pass back data */ +deliver_host_address = save_host_address; +return rc; +} + + + + +/************************************************* +* Check the given host item matches a list * +*************************************************/ +int +verify_check_given_host(const uschar **listptr, const host_item *host) +{ +return verify_check_this_host(listptr, NULL, host->name, host->address, NULL); +} + +/************************************************* +* Check the remote host matches a list * +*************************************************/ + +/* This is a front end to verify_check_this_host(), created because checking +the remote host is a common occurrence. With luck, a good compiler will spot +the tail recursion and optimize it. If there's no host address, this is +command-line SMTP input - check against an empty string for the address. + +Arguments: + listptr pointer to the host list + +Returns: the yield of verify_check_this_host(), + i.e. OK, FAIL, or DEFER +*/ + +int +verify_check_host(uschar **listptr) +{ +return verify_check_this_host(CUSS listptr, sender_host_cache, NULL, + (sender_host_address == NULL)? US"" : sender_host_address, NULL); +} + + + + + +/************************************************* +* Invert an IP address * +*************************************************/ + +/* Originally just used for DNS xBL lists, now also used for the +reverse_ip expansion operator. + +Arguments: + buffer where to put the answer + address the address to invert +*/ + +void +invert_address(uschar *buffer, uschar *address) +{ +int bin[4]; +uschar *bptr = buffer; + +/* If this is an IPv4 address mapped into IPv6 format, adjust the pointer +to the IPv4 part only. */ + +if (Ustrncmp(address, "::ffff:", 7) == 0) address += 7; + +/* Handle IPv4 address: when HAVE_IPV6 is false, the result of host_aton() is +always 1. */ + +if (host_aton(address, bin) == 1) + { + int i; + int x = bin[0]; + for (i = 0; i < 4; i++) + { + sprintf(CS bptr, "%d.", x & 255); + while (*bptr) bptr++; + x >>= 8; + } + } + +/* Handle IPv6 address. Actually, as far as I know, there are no IPv6 addresses +in any DNS black lists, and the format in which they will be looked up is +unknown. This is just a guess. */ + +#if HAVE_IPV6 +else + { + int i, j; + for (j = 3; j >= 0; j--) + { + int x = bin[j]; + for (i = 0; i < 8; i++) + { + sprintf(CS bptr, "%x.", x & 15); + while (*bptr) bptr++; + x >>= 4; + } + } + } +#endif + +/* Remove trailing period -- this is needed so that both arbitrary +dnsbl keydomains and inverted addresses may be combined with the +same format string, "%s.%s" */ + +*(--bptr) = 0; +} + + + +/************************************************* +* Perform a single dnsbl lookup * +*************************************************/ + +/* This function is called from verify_check_dnsbl() below. It is also called +recursively from within itself when domain and domain_txt are different +pointers, in order to get the TXT record from the alternate domain. + +Arguments: + domain the outer dnsbl domain + domain_txt alternate domain to lookup TXT record on success; when the + same domain is to be used, domain_txt == domain (that is, + the pointers must be identical, not just the text) + keydomain the current keydomain (for debug message) + prepend subdomain to lookup (like keydomain, but + reversed if IP address) + iplist the list of matching IP addresses, or NULL for "any" + bitmask true if bitmask matching is wanted + match_type condition for 'succeed' result + 0 => Any RR in iplist (=) + 1 => No RR in iplist (!=) + 2 => All RRs in iplist (==) + 3 => Some RRs not in iplist (!==) + the two bits are defined as MT_NOT and MT_ALL + defer_return what to return for a defer + +Returns: OK if lookup succeeded + FAIL if not +*/ + +static int +one_check_dnsbl(uschar *domain, uschar *domain_txt, uschar *keydomain, + uschar *prepend, uschar *iplist, BOOL bitmask, int match_type, + int defer_return) +{ +dns_answer dnsa; +dns_scan dnss; +tree_node *t; +dnsbl_cache_block *cb; +int old_pool = store_pool; +uschar query[256]; /* DNS domain max length */ + +/* Construct the specific query domainname */ + +if (!string_format(query, sizeof(query), "%s.%s", prepend, domain)) + { + log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long " + "(ignored): %s...", query); + return FAIL; + } + +/* Look for this query in the cache. */ + +if ( (t = tree_search(dnsbl_cache, query)) + && (cb = t->data.ptr)->expiry > time(NULL) + ) + +/* Previous lookup was cached */ + + { + HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n"); + } + +/* If not cached from a previous lookup, we must do a DNS lookup, and +cache the result in permanent memory. */ + +else + { + uint ttl = 3600; + + store_pool = POOL_PERM; + + if (t) + { + HDEBUG(D_dnsbl) debug_printf("cached data found but past valid time; "); + } + + else + { /* Set up a tree entry to cache the lookup */ + t = store_get(sizeof(tree_node) + Ustrlen(query)); + Ustrcpy(t->name, query); + t->data.ptr = cb = store_get(sizeof(dnsbl_cache_block)); + (void)tree_insertnode(&dnsbl_cache, t); + } + + /* Do the DNS lookup . */ + + HDEBUG(D_dnsbl) debug_printf("new DNS lookup for %s\n", query); + cb->rc = dns_basic_lookup(&dnsa, query, T_A); + cb->text_set = FALSE; + cb->text = NULL; + cb->rhs = NULL; + + /* If the lookup succeeded, cache the RHS address. The code allows for + more than one address - this was for complete generality and the possible + use of A6 records. However, A6 records are no longer supported. Leave the code + here, just in case. + + Quite apart from one A6 RR generating multiple addresses, there are DNS + lists that return more than one A record, so we must handle multiple + addresses generated in that way as well. + + Mark the cache entry with the "now" plus the minimum of the address TTLs, + or some suitably far-future time if none were found. */ + + if (cb->rc == DNS_SUCCEED) + { + dns_record *rr; + dns_address **addrp = &(cb->rhs); + for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); + rr; + rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) + if (rr->type == T_A) + { + dns_address *da = dns_address_from_rr(&dnsa, rr); + if (da) + { + *addrp = da; + while (da->next) da = da->next; + addrp = &da->next; + if (ttl > rr->ttl) ttl = rr->ttl; + } + } + + /* If we didn't find any A records, change the return code. This can + happen when there is a CNAME record but there are no A records for what + it points to. */ + + if (!cb->rhs) cb->rc = DNS_NODATA; + } + + cb->expiry = time(NULL)+ttl; + store_pool = old_pool; + } + +/* We now have the result of the DNS lookup, either newly done, or cached +from a previous call. If the lookup succeeded, check against the address +list if there is one. This may be a positive equality list (introduced by +"="), a negative equality list (introduced by "!="), a positive bitmask +list (introduced by "&"), or a negative bitmask list (introduced by "!&").*/ + +if (cb->rc == DNS_SUCCEED) + { + dns_address *da = NULL; + uschar *addlist = cb->rhs->address; + + /* For A and AAAA records, there may be multiple addresses from multiple + records. For A6 records (currently not expected to be used) there may be + multiple addresses from a single record. */ + + for (da = cb->rhs->next; da; da = da->next) + addlist = string_sprintf("%s, %s", addlist, da->address); + + HDEBUG(D_dnsbl) debug_printf("DNS lookup for %s succeeded (yielding %s)\n", + query, addlist); + + /* Address list check; this can be either for equality, or via a bitmask. + In the latter case, all the bits must match. */ + + if (iplist) + { + for (da = cb->rhs; da; da = da->next) + { + int ipsep = ','; + uschar ip[46]; + const uschar *ptr = iplist; + uschar *res; + + /* Handle exact matching */ + + if (!bitmask) + { + while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip)))) + if (Ustrcmp(CS da->address, ip) == 0) + break; + } + + /* Handle bitmask matching */ + + else + { + int address[4]; + int mask = 0; + + /* At present, all known DNS blocking lists use A records, with + IPv4 addresses on the RHS encoding the information they return. I + wonder if this will linger on as the last vestige of IPv4 when IPv6 + is ubiquitous? Anyway, for now we use paranoia code to completely + ignore IPv6 addresses. The default mask is 0, which always matches. + We change this only for IPv4 addresses in the list. */ + + if (host_aton(da->address, address) == 1) mask = address[0]; + + /* Scan the returned addresses, skipping any that are IPv6 */ + + while ((res = string_nextinlist(&ptr, &ipsep, ip, sizeof(ip)))) + { + if (host_aton(ip, address) != 1) continue; + if ((address[0] & mask) == address[0]) break; + } + } + + /* If either + + (a) An IP address in an any ('=') list matched, or + (b) No IP address in an all ('==') list matched + + then we're done searching. */ + + if (((match_type & MT_ALL) != 0) == (res == NULL)) break; + } + + /* If da == NULL, either + + (a) No IP address in an any ('=') list matched, or + (b) An IP address in an all ('==') list didn't match + + so behave as if the DNSBL lookup had not succeeded, i.e. the host is not on + the list. */ + + if ((match_type == MT_NOT || match_type == MT_ALL) != (da == NULL)) + { + HDEBUG(D_dnsbl) + { + uschar *res = NULL; + switch(match_type) + { + case 0: + res = US"was no match"; break; + case MT_NOT: + res = US"was an exclude match"; break; + case MT_ALL: + res = US"was an IP address that did not match"; break; + case MT_NOT|MT_ALL: + res = US"were no IP addresses that did not match"; break; + } + debug_printf("=> but we are not accepting this block class because\n"); + debug_printf("=> there %s for %s%c%s\n", + res, + ((match_type & MT_ALL) == 0)? "" : "=", + bitmask? '&' : '=', iplist); + } + return FAIL; + } + } + + /* Either there was no IP list, or the record matched, implying that the + domain is on the list. We now want to find a corresponding TXT record. If an + alternate domain is specified for the TXT record, call this function + recursively to look that up; this has the side effect of re-checking that + there is indeed an A record at the alternate domain. */ + + if (domain_txt != domain) + return one_check_dnsbl(domain_txt, domain_txt, keydomain, prepend, NULL, + FALSE, match_type, defer_return); + + /* If there is no alternate domain, look up a TXT record in the main domain + if it has not previously been cached. */ + + if (!cb->text_set) + { + cb->text_set = TRUE; + if (dns_basic_lookup(&dnsa, query, T_TXT) == DNS_SUCCEED) + { + dns_record *rr; + for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS); + rr; + rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) + if (rr->type == T_TXT) break; + if (rr) + { + int len = (rr->data)[0]; + if (len > 511) len = 127; + store_pool = POOL_PERM; + cb->text = string_sprintf("%.*s", len, CUS (rr->data+1)); + store_pool = old_pool; + } + } + } + + dnslist_value = addlist; + dnslist_text = cb->text; + return OK; + } + +/* There was a problem with the DNS lookup */ + +if (cb->rc != DNS_NOMATCH && cb->rc != DNS_NODATA) + { + log_write(L_dnslist_defer, LOG_MAIN, + "DNS list lookup defer (probably timeout) for %s: %s", query, + (defer_return == OK)? US"assumed in list" : + (defer_return == FAIL)? US"assumed not in list" : + US"returned DEFER"); + return defer_return; + } + +/* No entry was found in the DNS; continue for next domain */ + +HDEBUG(D_dnsbl) + { + debug_printf("DNS lookup for %s failed\n", query); + debug_printf("=> that means %s is not listed at %s\n", + keydomain, domain); + } + +return FAIL; +} + + + + +/************************************************* +* Check host against DNS black lists * +*************************************************/ + +/* This function runs checks against a list of DNS black lists, until one +matches. Each item on the list can be of the form + + domain=ip-address/key + +The domain is the right-most domain that is used for the query, for example, +blackholes.mail-abuse.org. If the IP address is present, there is a match only +if the DNS lookup returns a matching IP address. Several addresses may be +given, comma-separated, for example: x.y.z=127.0.0.1,127.0.0.2. + +If no key is given, what is looked up in the domain is the inverted IP address +of the current client host. If a key is given, it is used to construct the +domain for the lookup. For example: + + dsn.rfc-ignorant.org/$sender_address_domain + +After finding a match in the DNS, the domain is placed in $dnslist_domain, and +then we check for a TXT record for an error message, and if found, save its +value in $dnslist_text. We also cache everything in a tree, to optimize +multiple lookups. + +The TXT record is normally looked up in the same domain as the A record, but +when many lists are combined in a single DNS domain, this will not be a very +specific message. It is possible to specify a different domain for looking up +TXT records; this is given before the main domain, comma-separated. For +example: + + dnslists = http.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.2 : \ + socks.dnsbl.sorbs.net,dnsbl.sorbs.net=127.0.0.3 + +The caching ensures that only one lookup in dnsbl.sorbs.net is done. + +Note: an address for testing RBL is 192.203.178.39 +Note: an address for testing DUL is 192.203.178.4 +Note: a domain for testing RFCI is example.tld.dsn.rfc-ignorant.org + +Arguments: + where the acl type + listptr the domain/address/data list + log_msgptr log message on error + +Returns: OK successful lookup (i.e. the address is on the list), or + lookup deferred after +include_unknown + FAIL name not found, or no data found for the given type, or + lookup deferred after +exclude_unknown (default) + DEFER lookup failure, if +defer_unknown was set +*/ + +int +verify_check_dnsbl(int where, const uschar ** listptr, uschar ** log_msgptr) +{ +int sep = 0; +int defer_return = FAIL; +const uschar *list = *listptr; +uschar *domain; +uschar *s; +uschar buffer[1024]; +uschar revadd[128]; /* Long enough for IPv6 address */ + +/* Indicate that the inverted IP address is not yet set up */ + +revadd[0] = 0; + +/* In case this is the first time the DNS resolver is being used. */ + +dns_init(FALSE, FALSE, FALSE); /*XXX dnssec? */ + +/* Loop through all the domains supplied, until something matches */ + +while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL) + { + int rc; + BOOL bitmask = FALSE; + int match_type = 0; + uschar *domain_txt; + uschar *comma; + uschar *iplist; + uschar *key; + + HDEBUG(D_dnsbl) debug_printf("DNS list check: %s\n", domain); + + /* Deal with special values that change the behaviour on defer */ + + if (domain[0] == '+') + { + if (strcmpic(domain, US"+include_unknown") == 0) defer_return = OK; + else if (strcmpic(domain, US"+exclude_unknown") == 0) defer_return = FAIL; + else if (strcmpic(domain, US"+defer_unknown") == 0) defer_return = DEFER; + else + log_write(0, LOG_MAIN|LOG_PANIC, "unknown item in dnslist (ignored): %s", + domain); + continue; + } + + /* See if there's explicit data to be looked up */ + + if ((key = Ustrchr(domain, '/'))) *key++ = 0; + + /* See if there's a list of addresses supplied after the domain name. This is + introduced by an = or a & character; if preceded by = we require all matches + and if preceded by ! we invert the result. */ + + if (!(iplist = Ustrchr(domain, '='))) + { + bitmask = TRUE; + iplist = Ustrchr(domain, '&'); + } + + if (iplist) /* Found either = or & */ + { + if (iplist > domain && iplist[-1] == '!') /* Handle preceding ! */ + { + match_type |= MT_NOT; + iplist[-1] = 0; + } + + *iplist++ = 0; /* Terminate domain, move on */ + + /* If we found = (bitmask == FALSE), check for == or =& */ + + if (!bitmask && (*iplist == '=' || *iplist == '&')) + { + bitmask = *iplist++ == '&'; + match_type |= MT_ALL; + } + } + + + /* If there is a comma in the domain, it indicates that a second domain for + looking up TXT records is provided, before the main domain. Otherwise we must + set domain_txt == domain. */ + + domain_txt = domain; + comma = Ustrchr(domain, ','); + if (comma != NULL) + { + *comma++ = 0; + domain = comma; + } + + /* Check that what we have left is a sensible domain name. There is no reason + why these domains should in fact use the same syntax as hosts and email + domains, but in practice they seem to. However, there is little point in + actually causing an error here, because that would no doubt hold up incoming + mail. Instead, I'll just log it. */ + + for (s = domain; *s != 0; s++) + { + if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_') + { + log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains " + "strange characters - is this right?", domain); + break; + } + } + + /* Check the alternate domain if present */ + + if (domain_txt != domain) for (s = domain_txt; *s != 0; s++) + { + if (!isalnum(*s) && *s != '-' && *s != '.' && *s != '_') + { + log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains " + "strange characters - is this right?", domain_txt); + break; + } + } + + /* If there is no key string, construct the query by adding the domain name + onto the inverted host address, and perform a single DNS lookup. */ + + if (key == NULL) + { + if (where == ACL_WHERE_NOTSMTP_START || where == ACL_WHERE_NOTSMTP) + { + *log_msgptr = string_sprintf + ("cannot test auto-keyed dnslists condition in %s ACL", + acl_wherenames[where]); + return ERROR; + } + if (sender_host_address == NULL) return FAIL; /* can never match */ + if (revadd[0] == 0) invert_address(revadd, sender_host_address); + rc = one_check_dnsbl(domain, domain_txt, sender_host_address, revadd, + iplist, bitmask, match_type, defer_return); + if (rc == OK) + { + dnslist_domain = string_copy(domain_txt); + dnslist_matched = string_copy(sender_host_address); + HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n", + sender_host_address, dnslist_domain); + } + if (rc != FAIL) return rc; /* OK or DEFER */ + } + + /* If there is a key string, it can be a list of domains or IP addresses to + be concatenated with the main domain. */ + + else + { + int keysep = 0; + BOOL defer = FALSE; + uschar *keydomain; + uschar keybuffer[256]; + uschar keyrevadd[128]; + + while ((keydomain = string_nextinlist(CUSS &key, &keysep, keybuffer, + sizeof(keybuffer))) != NULL) + { + uschar *prepend = keydomain; + + if (string_is_ip_address(keydomain, NULL) != 0) + { + invert_address(keyrevadd, keydomain); + prepend = keyrevadd; + } + + rc = one_check_dnsbl(domain, domain_txt, keydomain, prepend, iplist, + bitmask, match_type, defer_return); + + if (rc == OK) + { + dnslist_domain = string_copy(domain_txt); + dnslist_matched = string_copy(keydomain); + HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n", + keydomain, dnslist_domain); + return OK; + } + + /* If the lookup deferred, remember this fact. We keep trying the rest + of the list to see if we get a useful result, and if we don't, we return + DEFER at the end. */ + + if (rc == DEFER) defer = TRUE; + } /* continue with next keystring domain/address */ + + if (defer) return DEFER; + } + } /* continue with next dnsdb outer domain */ + +return FAIL; +} + +/* vi: aw ai sw=2 +*/ +/* End of verify.c */ |