--- /dev/null
+/* $Cambridge: exim/src/src/verify.c,v 1.1 2004/10/07 10:39:01 ph10 Exp $ */
+
+/*************************************************
+* Exim - an Internet mail transport agent *
+*************************************************/
+
+/* Copyright (c) University of Cambridge 1995 - 2004 */
+/* 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"
+
+
+/* Structure for caching DNSBL lookups */
+
+typedef struct dnsbl_cache_block {
+ dns_address *rhs;
+ uschar *text;
+ int rc;
+ BOOL text_set;
+} dnsbl_cache_block;
+
+
+/* Anchor for DNSBL cache */
+
+static tree_node *dnsbl_cache = NULL;
+
+
+
+/*************************************************
+* 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, uschar *key, uschar *type,
+ int positive_expire, int negative_expire)
+{
+BOOL negative;
+int length, expire;
+time_t now;
+dbdata_callout_cache *cache_record;
+
+cache_record = dbfn_read_with_length(dbm_file, key, &length);
+
+if (cache_record == NULL)
+ {
+ HDEBUG(D_verify) debug_printf("callout cache: no %s record found\n", type);
+ 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\n", type);
+ 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\n", type);
+return cache_record;
+}
+
+
+
+/*************************************************
+* 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)
+ 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_random => do the "random" thing
+ vopt_callout_recipsender => use real sender for recipient
+ vopt_callout_recippmaster => use postmaster for recipient
+ 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 options, uschar *se_mailfrom,
+ uschar *pm_mailfrom)
+{
+BOOL is_recipient = (options & vopt_is_recipient) != 0;
+BOOL callout_no_cache = (options & vopt_callout_no_cache) != 0;
+BOOL callout_random = (options & vopt_callout_random) != 0;
+
+int yield = OK;
+BOOL done = FALSE;
+uschar *address_key;
+uschar *from_address;
+uschar *random_local_part = NULL;
+open_db dbblock;
+open_db *dbm_file = NULL;
+dbdata_callout_cache new_domain_record;
+dbdata_callout_cache_address new_address_record;
+host_item *host;
+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. */
+
+address_key = addr->address;
+from_address = US"";
+
+if (is_recipient)
+ {
+ if ((options & vopt_callout_recipsender) != 0)
+ {
+ address_key = string_sprintf("%s/<%s>", addr->address, sender_address);
+ from_address = sender_address;
+ }
+ else if ((options & vopt_callout_recippmaster) != 0)
+ {
+ address_key = string_sprintf("%s/<postmaster@%s>", addr->address,
+ qualify_domain_sender);
+ from_address = string_sprintf("postmaster@%s", qualify_domain_sender);
+ }
+ }
+
+/* For a sender callout, we must adjust the key if the mailfrom address is not
+empty. */
+
+else
+ {
+ from_address = (se_mailfrom == NULL)? US"" : se_mailfrom;
+ if (from_address[0] != 0)
+ address_key = string_sprintf("%s/<%s>", addr->address, from_address);
+ }
+
+/* Open the callout cache database, it it exists, for reading only at this
+stage, unless caching has been disabled. */
+
+if (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)) == NULL)
+ {
+ HDEBUG(D_verify) debug_printf("callout cache: not available\n");
+ }
+
+/* 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. */
+
+if (dbm_file != NULL)
+ {
+ 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 != NULL)
+ {
+ /* If an early command (up to and including MAIL FROM:<>) was rejected,
+ there is no point carrying on. The callout fails. */
+
+ if (cache_record->result == ccache_reject)
+ {
+ setflag(addr, af_verify_nsfail);
+ 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;
+ goto END_CALLOUT;
+ }
+
+ /* 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 (callout_random) switch(cache_record->random_result)
+ {
+ case ccache_accept:
+ HDEBUG(D_verify)
+ debug_printf("callout cache: domain accepts random addresses\n");
+ goto END_CALLOUT; /* Default yield is OK */
+
+ case ccache_reject:
+ HDEBUG(D_verify)
+ debug_printf("callout cache: domain rejects random addresses\n");
+ callout_random = FALSE;
+ 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");
+ goto END_CACHE;
+ }
+
+ /* 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_mailfrom != NULL)
+ {
+ 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;
+ setflag(addr, af_verify_pmfail);
+ addr->user_message = US"(result of earlier verification reused).";
+ goto END_CALLOUT;
+ }
+ 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");
+ goto END_CACHE;
+ }
+
+ /* 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_mailfrom = 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).
+ */
+
+ 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);
+
+ if (cache_address_record != NULL)
+ {
+ 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";
+ yield = FAIL;
+ }
+ goto END_CALLOUT;
+ }
+
+ /* Close the cache database while we actually do the callout for real. */
+
+ END_CACHE:
+ dbfn_close(dbm_file);
+ dbm_file = NULL;
+ }
+
+/* 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 randomming. */
+
+if (callout_random && callout_random_local_part != NULL)
+ {
+ random_local_part = expand_string(callout_random_local_part);
+ if (random_local_part == NULL)
+ log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand "
+ "callout_random_local_part: %s", expand_string_message);
+ }
+
+/* Default the overall callout timeout if not set, and record the time we are
+starting so that we can enforce it. */
+
+if (callout_overall < 0) callout_overall = 4 * callout;
+callout_start_time = time(NULL);
+
+/* Now make connections to the hosts and do real callouts. The list of hosts
+is passed in as an argument. */
+
+for (host = host_list; host != NULL && !done; host = host->next)
+ {
+ smtp_inblock inblock;
+ smtp_outblock outblock;
+ int host_af;
+ int port = 25;
+ uschar *helo = US"HELO";
+ uschar *interface = NULL; /* Outgoing interface to use; NULL => any */
+ uschar inbuffer[4096];
+ uschar outbuffer[1024];
+ uschar responsebuffer[4096];
+
+ clearflag(addr, af_verify_pmfail); /* postmaster callout flag */
+ clearflag(addr, af_verify_nsfail); /* null sender callout flag */
+
+ /* Skip this host if we don't have an IP address for it. */
+
+ if (host->address == NULL)
+ {
+ 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, ':') == NULL)? AF_INET:AF_INET6;
+
+ /* Expand and interpret the interface and port strings. 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;
+ if (!smtp_get_interface(tf->interface, host_af, addr, NULL, &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);
+ deliver_host = deliver_host_address = NULL;
+
+ /* Set HELO string according to the protocol */
+
+ if (Ustrcmp(tf->protocol, "lmtp") == 0) helo = US"LHLO";
+
+ HDEBUG(D_verify) debug_printf("interface=%s port=%d\n", interface, port);
+
+ /* Set up the buffer for reading SMTP response packets. */
+
+ inblock.buffer = inbuffer;
+ inblock.buffersize = sizeof(inbuffer);
+ inblock.ptr = inbuffer;
+ inblock.ptrend = inbuffer;
+
+ /* Set up the buffer for holding SMTP commands while pipelining */
+
+ outblock.buffer = outbuffer;
+ outblock.buffersize = sizeof(outbuffer);
+ outblock.ptr = outbuffer;
+ outblock.cmd_count = 0;
+ outblock.authenticating = FALSE;
+
+ /* Connect to the host; on failure, just loop for the next one, but we
+ set the error for the last one. */
+
+ inblock.sock = outblock.sock =
+ smtp_connect(host, host_af, port, interface, callout, TRUE);
+ if (inblock.sock < 0)
+ {
+ addr->message = string_sprintf("could not connect to %s [%s]: %s",
+ host->name, host->address, strerror(errno));
+ continue;
+ }
+
+ /* Wait for initial response, and then run the initial SMTP commands. The
+ smtp_write_command() function leaves its command in big_buffer. This is
+ used in error responses. Initialize it in case the connection is
+ rejected. */
+
+ Ustrcpy(big_buffer, "initial connection");
+
+ done =
+ smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
+ '2', callout) &&
+
+ smtp_write_command(&outblock, FALSE, "%s %s\r\n", helo,
+ smtp_active_hostname) >= 0 &&
+ smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
+ '2', callout) &&
+
+ smtp_write_command(&outblock, FALSE, "MAIL FROM:<%s>\r\n",
+ from_address) >= 0 &&
+ smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
+ '2', callout);
+
+ /* If the host gave an initial error, or does not accept HELO or MAIL
+ FROM:<>, arrange to cache this information, but don't record anything for an
+ I/O error or a defer. Do not cache rejections when a non-empty sender has
+ been used, because that blocks the whole domain for all senders. */
+
+ if (!done)
+ {
+ if (errno == 0 && responsebuffer[0] == '5')
+ {
+ setflag(addr, af_verify_nsfail);
+ if (from_address[0] == 0) new_domain_record.result = ccache_reject;
+ }
+ }
+
+ /* Otherwise, proceed to check a "random" address (if required), then the
+ given address, and the postmaster address (if required). Between each check,
+ issue RSET, because some servers accept only one recipient after MAIL
+ FROM:<>. */
+
+ else
+ {
+ new_domain_record.result = ccache_accept;
+
+ /* Do the random local part check first */
+
+ if (random_local_part != NULL)
+ {
+ uschar randombuffer[1024];
+ BOOL random_ok =
+ smtp_write_command(&outblock, FALSE,
+ "RCPT TO:<%.1000s@%.1000s>\r\n", random_local_part,
+ addr->domain) >= 0 &&
+ smtp_read_response(&inblock, randombuffer,
+ sizeof(randombuffer), '2', callout);
+
+ /* Remember when we last did a random test */
+
+ new_domain_record.random_stamp = time(NULL);
+
+ /* If accepted, we aren't going to do any further tests below. */
+
+ if (random_ok)
+ {
+ new_domain_record.random_result = ccache_accept;
+ }
+
+ /* 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. */
+
+ else if (errno == 0)
+ {
+ if (randombuffer[0] == '5')
+ new_domain_record.random_result = ccache_reject;
+
+ done =
+ smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
+ smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
+ '2', callout) &&
+
+ smtp_write_command(&outblock, FALSE, "MAIL FROM:<>\r\n") >= 0 &&
+ smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
+ '2', callout);
+ }
+ else done = FALSE; /* Some timeout/connection problem */
+ } /* Random check */
+
+ /* If the host is accepting all local parts, as determined by the "random"
+ check, we don't need to waste time doing any further checking. */
+
+ if (new_domain_record.random_result != ccache_accept && done)
+ {
+ done =
+ smtp_write_command(&outblock, FALSE, "RCPT TO:<%.1000s>\r\n",
+ addr->address) >= 0 &&
+ smtp_read_response(&inblock, responsebuffer, sizeof(responsebuffer),
+ '2', callout);
+
+ if (done)
+ new_address_record.result = ccache_accept;
+ else if (errno == 0 && responsebuffer[0] == '5')
+ new_address_record.result = ccache_reject;
+
+ /* Do postmaster check if requested */
+
+ if (done && pm_mailfrom != NULL)
+ {
+ done =
+ smtp_write_command(&outblock, FALSE, "RSET\r\n") >= 0 &&
+ smtp_read_response(&inblock, responsebuffer,
+ sizeof(responsebuffer), '2', callout) &&
+
+ smtp_write_command(&outblock, FALSE,
+ "MAIL FROM:<%s>\r\n", pm_mailfrom) >= 0 &&
+ smtp_read_response(&inblock, responsebuffer,
+ sizeof(responsebuffer), '2', callout) &&
+
+ smtp_write_command(&outblock, FALSE,
+ "RCPT TO:<postmaster@%.1000s>\r\n", addr->domain) >= 0 &&
+ smtp_read_response(&inblock, responsebuffer,
+ sizeof(responsebuffer), '2', callout);
+
+ new_domain_record.postmaster_stamp = time(NULL);
+
+ if (done)
+ new_domain_record.postmaster_result = ccache_accept;
+ else if (errno == 0 && responsebuffer[0] == '5')
+ {
+ setflag(addr, af_verify_pmfail);
+ new_domain_record.postmaster_result = ccache_reject;
+ }
+ }
+ } /* Random not accepted */
+ } /* MAIL FROM:<> accepted */
+
+ /* 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. */
+
+ if (!done)
+ {
+ if (errno == ETIMEDOUT)
+ {
+ HDEBUG(D_verify) debug_printf("SMTP timeout\n");
+ }
+ else if (errno == 0)
+ {
+ if (*responsebuffer == 0) Ustrcpy(responsebuffer, US"connection dropped");
+
+ addr->message =
+ string_sprintf("response to \"%s\" from %s [%s] was: %s",
+ big_buffer, host->name, host->address,
+ string_printing(responsebuffer));
+
+ addr->user_message = is_recipient?
+ string_sprintf("Callout verification failed:\n%s", responsebuffer)
+ :
+ string_sprintf("Called: %s\nSent: %s\nResponse: %s",
+ host->address, big_buffer, responsebuffer);
+
+ /* Hard rejection ends the process */
+
+ if (responsebuffer[0] == '5') /* Address rejected */
+ {
+ yield = FAIL;
+ done = TRUE;
+ }
+ }
+ }
+
+ /* End the SMTP conversation and close the connection. */
+
+ (void)smtp_write_command(&outblock, FALSE, "QUIT\r\n");
+ close(inblock.sock);
+ } /* 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.
+
+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 or ccache_reject. */
+
+if (!callout_no_cache && new_domain_record.result != ccache_unknown)
+ {
+ if ((dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE))
+ == NULL)
+ {
+ HDEBUG(D_verify) debug_printf("callout cache: not available\n");
+ }
+ else
+ {
+ (void)dbfn_write(dbm_file, addr->domain, &new_domain_record,
+ (int)sizeof(dbdata_callout_cache));
+ HDEBUG(D_verify) debug_printf("wrote callout cache domain record:\n"
+ " result=%d postmaster=%d random=%d\n",
+ new_domain_record.result,
+ new_domain_record.postmaster_result,
+ new_domain_record.random_result);
+ }
+ }
+
+/* If a definite result was obtained for the callout, cache it unless caching
+is disabled. */
+
+if (done)
+ {
+ if (!callout_no_cache && new_address_record.result != ccache_unknown)
+ {
+ if (dbm_file == NULL)
+ dbm_file = dbfn_open(US"callout", O_RDWR|O_CREAT, &dbblock, FALSE);
+ if (dbm_file == NULL)
+ {
+ HDEBUG(D_verify) debug_printf("no callout cache available\n");
+ }
+ else
+ {
+ (void)dbfn_write(dbm_file, address_key, &new_address_record,
+ (int)sizeof(dbdata_callout_cache_address));
+ HDEBUG(D_verify) debug_printf("wrote %s callout cache address record\n",
+ (new_address_record.result == ccache_accept)? "positive" : "negative");
+ }
+ }
+ } /* done */
+
+/* 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. */
+
+else /* !done */
+ {
+ uschar *dullmsg = string_sprintf("Could not complete %s verify callout",
+ is_recipient? "recipient" : "sender");
+ yield = DEFER;
+
+ if (host_list->next != NULL || addr->message == NULL) addr->message = dullmsg;
+
+ addr->user_message = (!smtp_return_error_details)? dullmsg :
+ 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,
+ 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.");
+
+ /* Force a specific error code */
+
+ addr->basic_errno = ERRNO_CALLOUTDEFER;
+ }
+
+/* Come here from within the cache-reading code on fast-track exit. */
+
+END_CALLOUT:
+if (dbm_file != NULL) dbfn_close(dbm_file);
+return yield;
+}
+
+
+
+/*************************************************
+* 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;
+ }
+return yield;
+}
+
+
+
+
+/*************************************************
+* 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
+
+ These ones are used by do_callout() -- the options variable
+ is passed to it.
+
+ 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 connections and commands
+ callout_overall if > 0, gives overall timeout for the callout function;
+ if < 0, a default is used (see do_callout())
+ 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 *f, int options, int callout,
+ int callout_overall, uschar *se_mailfrom, uschar *pm_mailfrom, BOOL *routed)
+{
+BOOL allok = TRUE;
+BOOL full_info = (f == NULL)? FALSE : (debug_selector != 0);
+BOOL is_recipient = (options & vopt_is_recipient) != 0;
+BOOL expn = (options & vopt_expn) != 0;
+
+int i;
+int yield = OK;
+int verify_type = expn? v_expn :
+ address_test_mode? v_none :
+ 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 *ko_prefix, *cr;
+uschar *address = vaddr->address;
+uschar *save_sender;
+uschar null_sender[] = { 0 }; /* Ensure writeable memory */
+
+/* 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) == 0)
+ {
+ if (f != NULL)
+ fprintf(f, "%sA domain is required for \"%s\"%s\n", ko_prefix, address,
+ cr);
+ return FAIL;
+ }
+ address = rewrite_address_qualify(address, is_recipient);
+ }
+
+DEBUG(D_verify)
+ {
+ debug_printf(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
+ debug_printf("%s %s\n", 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 != NULL)
+ {
+ uschar *old = address;
+ address = rewrite_address(address, 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 (f != NULL && !expn) fprintf(f, "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)) == 0)
+ 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] == 0) return OK;
+
+/* 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;
+
+/* 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 != NULL)
+ {
+ 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 (f != NULL)
+ {
+ BOOL allow;
+
+ if (addr->address[0] == '>')
+ {
+ allow = testflag(addr, af_allow_reply);
+ fprintf(f, "%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(f, "%s -> %s", addr->parent->address, addr->address);
+ }
+
+ if (addr->basic_errno == ERRNO_BADTRANSPORT)
+ fprintf(f, "\n*** Error in setting up pipe, file, or autoreply:\n"
+ "%s\n", addr->message);
+ else if (allow)
+ fprintf(f, "\n transport = %s\n", addr->transport->name);
+ else
+ fprintf(f, " *** forbidden ***\n");
+ }
+ continue;
+ }
+
+ /* Just in case some router parameter refers to it. */
+
+ return_path = (addr->p.errors_address != NULL)?
+ addr->p.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 != NULL) *routed = FALSE;
+ if ((rc = deliver_split_address(addr)) == OK)
+ {
+ if (!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 != NULL) *routed = TRUE;
+ if (callout > 0)
+ {
+ host_item *host_list = addr->host_list;
+
+ /* Default, if no remote transport, to NULL for the interface (=> any),
+ "smtp" for the port, and "smtp" for the protocol. */
+
+ transport_feedback tf = { NULL, US"smtp", US"smtp", NULL, FALSE, 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 (addr->transport != NULL && !addr->transport->info->local)
+ {
+ (void)(addr->transport->setup)(addr->transport, addr, &tf, 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 != NULL && (host_list == NULL || tf.hosts_override))
+ {
+ uschar *s;
+
+ host_list = NULL; /* Ignore the router's hosts */
+
+ deliver_domain = addr->domain;
+ deliver_localpart = addr->local_part;
+ s = expand_string(tf.hosts);
+ deliver_domain = deliver_localpart = NULL;
+
+ if (s == NULL)
+ {
+ log_write(0, LOG_MAIN|LOG_PANIC, "failed to expand list of hosts "
+ "\"%s\" in %s transport for callout: %s", tf.hosts,
+ addr->transport->name, expand_string_message);
+ }
+ else
+ {
+ uschar *canonical_name;
+ host_item *host;
+ 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. */
+
+ for (host = host_list; host != NULL; host = host->next)
+ {
+ if (tf.gethostbyname || string_is_ip_address(host->name, NULL))
+ (void)host_find_byname(host, NULL, &canonical_name, TRUE);
+ else
+ {
+ int flags = HOST_FIND_BY_A;
+ if (tf.qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
+ if (tf.search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
+ (void)host_find_bydns(host, NULL, flags, NULL, NULL, NULL,
+ &canonical_name, NULL);
+ }
+ }
+ }
+ }
+ }
+
+ /* Can only do a callout if we have at least one host! */
+
+ if (host_list != NULL)
+ {
+ HDEBUG(D_verify) debug_printf("Attempting full verification using callout\n");
+ if (host_checking && !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
+ {
+ rc = do_callout(addr, host_list, &tf, callout, callout_overall,
+ options, se_mailfrom, pm_mailfrom);
+ }
+ }
+ else
+ {
+ HDEBUG(D_verify) debug_printf("Cannot do callout: neither router nor "
+ "transport provided a host list\n");
+ }
+ }
+ }
+
+ /* 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 (f != NULL)
+ {
+ fprintf(f, "%s%s %s", ko_prefix, address,
+ address_test_mode? "is undeliverable" : "failed to verify");
+ if (!expn && admin_user)
+ {
+ if (addr->basic_errno > 0)
+ fprintf(f, ": %s", strerror(addr->basic_errno));
+ if (addr->message != NULL)
+ fprintf(f, ":\n %s", addr->message);
+ }
+ fprintf(f, "%s\n", cr);
+ }
+
+ if (!full_info) return copy_error(vaddr, addr, FAIL);
+ else yield = FAIL;
+ }
+
+ /* Soft failure */
+
+ else if (rc == DEFER)
+ {
+ allok = FALSE;
+ if (f != NULL)
+ {
+ fprintf(f, "%s%s cannot be resolved at this time", ko_prefix, address);
+ if (!expn && admin_user)
+ {
+ if (addr->basic_errno > 0)
+ fprintf(f, ":\n %s", strerror(addr->basic_errno));
+ if (addr->message != NULL)
+ fprintf(f, ":\n %s", addr->message);
+ else if (addr->basic_errno <= 0)
+ fprintf(f, ":\n unknown error");
+ }
+
+ fprintf(f, "%s\n", cr);
+ }
+ if (!full_info) return copy_error(vaddr, addr, DEFER);
+ else if (yield == OK) yield = DEFER;
+ }
+
+ /* If we are handling EXPN, we do not want to continue to route beyond
+ the top level. */
+
+ else if (expn)
+ {
+ uschar *ok_prefix = US"250-";
+ if (addr_new == NULL)
+ {
+ if (addr_local == NULL && addr_remote == NULL)
+ fprintf(f, "250 mail to <%s> is discarded\r\n", address);
+ else
+ fprintf(f, "250 <%s>\r\n", address);
+ }
+ else while (addr_new != NULL)
+ {
+ address_item *addr2 = addr_new;
+ addr_new = addr2->next;
+ if (addr_new == NULL) ok_prefix = US"250 ";
+ fprintf(f, "%s<%s>\r\n", ok_prefix, addr2->address);
+ }
+ return OK;
+ }
+
+ /* 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 == NULL || /* No new address OR */
+ addr_new->next != NULL || /* More than one new address OR */
+ testflag(addr_new, af_pfr))) /* New address is pfr */
+ {
+ if (f != NULL) fprintf(f, "%s %s\n", address,
+ 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->p.address_data = addr->p.address_data;
+ return OK;
+ }
+ }
+ } /* 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 f 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 == NULL && addr_remote == NULL)
+ fprintf(f, "mail to %s is discarded\n", address);
+
+else for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++)
+ {
+ while (addr_list != NULL)
+ {
+ address_item *addr = addr_list;
+ address_item *p = addr->parent;
+ addr_list = addr->next;
+
+ fprintf(f, "%s", CS addr->address);
+ while (p != NULL)
+ {
+ fprintf(f, "\n <-- %s", p->address);
+ p = p->parent;
+ }
+ fprintf(f, "\n ");
+
+ /* Show router, and transport */
+
+ fprintf(f, "router = %s, ", addr->router->name);
+ fprintf(f, "transport = %s\n", (addr->transport == NULL)? US"unset" :
+ addr->transport->name);
+
+ /* 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 != NULL && addr->transport != NULL &&
+ !addr->transport->overrides_hosts)
+ {
+ host_item *h;
+ int maxlen = 0;
+ int maxaddlen = 0;
+ for (h = addr->host_list; h != NULL; h = h->next)
+ {
+ int len = Ustrlen(h->name);
+ if (len > maxlen) maxlen = len;
+ len = (h->address != NULL)? Ustrlen(h->address) : 7;
+ if (len > maxaddlen) maxaddlen = len;
+ }
+ for (h = addr->host_list; h != NULL; h = h->next)
+ {
+ int len = Ustrlen(h->name);
+ fprintf(f, " host %s ", h->name);
+ while (len++ < maxlen) fprintf(f, " ");
+ if (h->address != NULL)
+ {
+ fprintf(f, "[%s] ", h->address);
+ len = Ustrlen(h->address);
+ }
+ else if (!addr->transport->info->local) /* Omit [unknown] for local */
+ {
+ fprintf(f, "[unknown] ");
+ len = 7;
+ }
+ else len = -3;
+ while (len++ < maxaddlen) fprintf(f," ");
+ if (h->mx >= 0) fprintf(f, "MX=%d", h->mx);
+ if (h->port != PORT_NONE) fprintf(f, " port=%d", h->port);
+ if (h->status == hstatus_unusable) fprintf(f, " ** unusable **");
+ fprintf(f, "\n");
+ }
+ }
+ }
+ }
+
+return yield; /* Will be DEFER or FAIL if any one address has */
+}
+
+
+
+
+/*************************************************
+* Check headers for syntax errors *
+*************************************************/
+
+/* This function checks those header lines that contain addresses, and verifies
+that all the addresses therein are 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;
+
+for (h = header_list; h != NULL; 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++;
+
+ parse_allow_group = TRUE; /* Allow group syntax */
+
+ /* Loop for multiple addresses in the header */
+
+ 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. */
+
+ *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 != NULL && domain == 0)
+ {
+ if (h->type == htype_from || h->type == htype_sender)
+ {
+ if (!allow_unqualified_sender) recipient = NULL;
+ }
+ else
+ {
+ if (!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 == NULL && Ustrcmp(errmess, "empty address") != 0)
+ {
+ uschar *verb = US"is";
+ uschar *t = ss;
+ int len;
+
+ /* Arrange not to include any white space at the end in the
+ error message. */
+
+ while (t > s && isspace(t[-1])) t--;
+
+ /* Add the address which 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";
+ }
+
+ *msgptr = string_printing(
+ string_sprintf("%s: failing address in \"%.*s\" header %s: %.*s",
+ errmess, colon - h->text, h->text, verb, len, s));
+
+ return FAIL;
+ }
+
+ /* Advance to the next address */
+
+ s = ss + (terminator? 1:0);
+ while (isspace(*s)) s++;
+ } /* Next address */
+ } /* Next header */
+
+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)
+ se_mailfrom mailfrom for verify; NULL => ""
+ pm_mailfrom sender for pm callout check (passed to verify_address())
+ options callout options (passed to verify_address())
+
+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, uschar *se_mailfrom, uschar *pm_mailfrom,
+ int options)
+{
+static int header_types[] = { htype_sender, htype_reply_to, htype_from };
+int yield = FAIL;
+int i;
+
+for (i = 0; i < 3; i++)
+ {
+ header_line *h;
+ for (h = header_list; h != NULL; h = h->next)
+ {
+ int terminator, new_ok;
+ uschar *s, *ss, *endname;
+
+ if (h->type != header_types[i]) continue;
+ s = endname = Ustrchr(h->text, ':') + 1;
+
+ 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 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;
+ if (*log_msgptr != NULL)
+ {
+ while (ss > s && isspace(ss[-1])) ss--;
+ *log_msgptr = string_sprintf("syntax error in '%.*s' header when "
+ "scanning for sender: %s in \"%.*s\"",
+ endname - h->text, h->text, *log_msgptr, ss - s, s);
+ return FAIL;
+ }
+ }
+
+ /* Else go ahead with the sender verification. But is 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, 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 && smtp_return_error_details)
+ {
+ *user_msgptr = string_sprintf("Rejected after DATA: "
+ "could not verify \"%.*s\" header address\n%s: %s",
+ endname - h->text, h->text, vaddr->address, vaddr->message);
+ }
+
+ /* Success or defer */
+
+ if (new_ok == OK) return OK;
+ if (new_ok == DEFER) yield = DEFER;
+
+ /* Move on to any more addresses in the header */
+
+ s = ss;
+ }
+ }
+ }
+
+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)
+{
+int sock, host_af, qlen;
+int received_sender_port, received_interface_port, n;
+uschar *p;
+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;
+sock = ip_socket(SOCK_STREAM, host_af);
+if (sock < 0) return;
+
+if (ip_bind(sock, host_af, interface_address, 0) < 0)
+ {
+ DEBUG(D_ident) debug_printf("bind socket for ident failed: %s\n",
+ strerror(errno));
+ goto END_OFF;
+ }
+
+if (ip_connect(sock, host_af, sender_host_address, port, rfc1413_query_timeout)
+ < 0)
+ {
+ if (errno == ETIMEDOUT && (log_extra_selector & LX_ident_timeout) != 0)
+ {
+ 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;
+ }
+
+/* Construct and send the query. */
+
+sprintf(CS buffer, "%d , %d\r\n", sender_host_port, interface_port);
+qlen = Ustrlen(buffer);
+if (send(sock, buffer, qlen, 0) < 0)
+ {
+ DEBUG(D_ident) debug_printf("ident send failed: %s\n", 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(sock, 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. */
+
+sender_ident = string_printing(string_copyn(p, 127));
+DEBUG(D_ident) debug_printf("sender_ident = %s\n", sender_ident);
+
+END_OFF:
+close(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 the host name or NULL, implying use sender_host_name and
+ sender_host_aliases, looking them up if required
+ 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 failed to find the host name or IP address
+ unknown lookup type specified
+*/
+
+static int
+check_host(void *arg, uschar *ss, uschar **valueptr, uschar **error)
+{
+check_host_block *cb = (check_host_block *)arg;
+int maskoffset;
+BOOL isquery = FALSE;
+uschar *semicolon, *t;
+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;
+if it's "@[]" match against the local host's IP addresses. */
+
+if (*ss == '@')
+ {
+ if (ss[1] == 0) 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) comparision with the current IP address. */
+
+if (string_is_ip_address(ss, &maskoffset))
+ return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL);
+
+/* 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. 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 = Ustrchr(ss, ';')) != NULL)
+ {
+ int mlen = 0;
+ for (t = ss + 3; isdigit(*t); t++) mlen = mlen * 10 + *t - '0';
+ if (*t++ == '-')
+ {
+ int insize;
+ int search_type;
+ int incoming[4];
+ void *handle;
+ uschar *filename, *key, *result;
+ uschar buffer[64];
+
+ /* If no mask was supplied, set a negative value */
+
+ if (mlen == 0 && t == ss+4) mlen = -1;
+
+ /* 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
+ a single-key lookup, the key is the current IP address, masked
+ appropriately, and reconverted to text form, with the mask appended. */
+
+ if (mac_islookup(search_type, lookup_querystyle))
+ {
+ filename = NULL;
+ key = semicolon + 1;
+ }
+ else
+ {
+ insize = host_aton(cb->host_address, incoming);
+ host_mask(insize, incoming, mlen);
+ (void)host_nmtoa(insize, incoming, mlen, buffer);
+ key = buffer;
+ filename = semicolon + 1;
+ }
+
+ /* Now do the actual lookup; note that there is no search_close() because
+ of the caching arrangements. */
+
+ handle = search_open(filename, search_type, 0, NULL, NULL);
+ if (handle == 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 != NULL) *valueptr = result;
+ return (result != NULL)? OK : 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. 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;
+ rc = host_find_byname(&h, NULL, NULL, FALSE);
+ if (rc == HOST_FOUND || rc == HOST_FOUND_LOCAL)
+ {
+ host_item *hh;
+ for (hh = &h; hh != NULL; hh = hh->next)
+ {
+ if (Ustrcmp(hh->address, (Ustrchr(hh->address, ':') == NULL)?
+ cb->host_ipv4 : 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)
+ {
+ 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);
+ }
+
+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 == NULL)
+ {
+ 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 != NULL)
+ {
+ 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(uschar **listptr, unsigned int *cache_bits,
+ uschar *host_name, uschar *host_address, uschar **valueptr)
+{
+unsigned int *local_cache_bits = cache_bits;
+check_host_block cb;
+cb.host_name = host_name;
+cb.host_address = host_address;
+
+if (valueptr != NULL) *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;
+
+return match_check_list(listptr, 0, &hostlist_anchor, &local_cache_bits,
+ check_host, &cb, MCL_HOST,
+ (host_address == sender_host_address)? US"host" : host_address, valueptr);
+}
+
+
+
+
+/*************************************************
+* 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(listptr, sender_host_cache, NULL,
+ (sender_host_address == NULL)? US"" : sender_host_address, NULL);
+}
+
+
+
+
+
+/*************************************************
+* Invert an IP address for a DNS black list *
+*************************************************/
+
+/*
+Arguments:
+ buffer where to put the answer
+ address the address to invert
+*/
+
+static 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
+}
+
+
+
+/*************************************************
+* 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.
+
+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:
+ listptr the domain/address/data list
+
+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(uschar **listptr)
+{
+int sep = 0;
+int defer_return = FAIL;
+int old_pool = store_pool;
+BOOL invert_result = FALSE;
+uschar *list = *listptr;
+uschar *domain;
+uschar *s;
+uschar buffer[1024];
+uschar query[256]; /* DNS domain max length */
+uschar revadd[128]; /* Long enough for IPv6 address */
+
+/* Indicate that the inverted IP address is not yet set up */
+
+revadd[0] = 0;
+
+/* Loop through all the domains supplied, until something matches */
+
+while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
+ {
+ BOOL frc;
+ BOOL bitmask = FALSE;
+ dns_answer dnsa;
+ dns_scan dnss;
+ uschar *iplist;
+ uschar *key;
+ tree_node *t;
+ dnsbl_cache_block *cb;
+
+ 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 */
+
+ key = Ustrchr(domain, '/');
+ if (key != NULL) *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 invert the result.
+ */
+
+ iplist = Ustrchr(domain, '=');
+ if (iplist == NULL)
+ {
+ bitmask = TRUE;
+ iplist = Ustrchr(domain, '&');
+ }
+
+ if (iplist != NULL)
+ {
+ if (iplist > domain && iplist[-1] == '!')
+ {
+ invert_result = TRUE;
+ iplist[-1] = 0;
+ }
+ *iplist++ = 0;
+ }
+
+ /* 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 != '.')
+ {
+ log_write(0, LOG_MAIN, "dnslists domain \"%s\" contains "
+ "strange characters - is this right?", domain);
+ break;
+ }
+ }
+
+ /* Construct the query by adding the domain onto either the sending host
+ address, or the given key string. */
+
+ if (key == NULL)
+ {
+ if (sender_host_address == NULL) return FAIL; /* can never match */
+ if (revadd[0] == 0) invert_address(revadd, sender_host_address);
+ frc = string_format(query, sizeof(query), "%s%s", revadd, domain);
+ }
+ else
+ {
+ frc = string_format(query, sizeof(query), "%s.%s", key, domain);
+ }
+
+ if (!frc)
+ {
+ log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long "
+ "(ignored): %s...", query);
+ continue;
+ }
+
+ /* Look for this query in the cache. */
+
+ t = tree_search(dnsbl_cache, query);
+
+ /* If not cached from a previous lookup, we must do a DNS lookup, and
+ cache the result in permanent memory. */
+
+ if (t == NULL)
+ {
+ store_pool = POOL_PERM;
+
+ /* In case this is the first time the DNS resolver is being used. */
+
+ dns_init(FALSE, FALSE);
+
+ /* 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 loopup . */
+
+ 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 have been reduced to experimental
+ status (August 2001) and may die out. So they may never get used at all,
+ let alone in dnsbl records. However, 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. */
+
+ if (cb->rc == DNS_SUCCEED)
+ {
+ dns_record *rr;
+ dns_address **addrp = &(cb->rhs);
+ for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
+ rr != NULL;
+ rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
+ {
+ if (rr->type == T_A)
+ {
+ dns_address *da = dns_address_from_rr(&dnsa, rr);
+ if (da != NULL)
+ {
+ *addrp = da;
+ while (da->next != NULL) da = da->next;
+ addrp = &(da->next);
+ }
+ }
+ }
+
+ /* 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 == NULL) cb->rc = DNS_NODATA;
+ }
+
+ store_pool = old_pool;
+ }
+
+ /* Previous lookup was cached */
+
+ else
+ {
+ HDEBUG(D_dnsbl) debug_printf("using result of previous DNS lookup\n");
+ cb = t->data.ptr;
+ }
+
+ /* 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 != NULL; 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 != NULL)
+ {
+ int ipsep = ',';
+ uschar ip[46];
+ uschar *ptr = iplist;
+
+ while (string_nextinlist(&ptr, &ipsep, ip, sizeof(ip)) != NULL)
+ {
+ /* Handle exact matching */
+ if (!bitmask)
+ {
+ for (da = cb->rhs; da != NULL; da = da->next)
+ {
+ 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(ip, address) == 1) mask = address[0];
+
+ /* Scan the returned addresses, skipping any that are IPv6 */
+
+ for (da = cb->rhs; da != NULL; da = da->next)
+ {
+ if (host_aton(da->address, address) != 1) continue;
+ if ((address[0] & mask) == mask) break;
+ }
+ }
+
+ /* Break out if a match has been found */
+
+ if (da != NULL) break;
+ }
+
+ /* If either
+
+ (a) No IP address in a positive list matched, or
+ (b) An IP address in a negative list did match
+
+ then behave as if the DNSBL lookup had not succeeded, i.e. the host is
+ not on the list. */
+
+ if (invert_result != (da == NULL))
+ {
+ HDEBUG(D_dnsbl)
+ {
+ debug_printf("=> but we are not accepting this block class because\n");
+ debug_printf("=> there was %s match for %c%s\n",
+ invert_result? "an exclude":"no", bitmask? '&' : '=', iplist);
+ }
+ continue; /* With next DNSBL domain */
+ }
+ }
+
+ /* Either there was no IP list, or the record matched. Look up a TXT record
+ if it hasn't previously been done. */
+
+ 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 != NULL;
+ rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
+ if (rr->type == T_TXT) break;
+ if (rr != NULL)
+ {
+ int len = (rr->data)[0];
+ if (len > 511) len = 127;
+ store_pool = POOL_PERM;
+ cb->text = string_sprintf("%.*s", len, (const uschar *)(rr->data+1));
+ store_pool = old_pool;
+ }
+ }
+ }
+
+ HDEBUG(D_dnsbl)
+ {
+ debug_printf("=> that means %s is listed at %s\n",
+ (key == NULL)? sender_host_address : key, domain);
+ }
+
+ dnslist_domain = string_copy(domain);
+ 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",
+ (key == NULL)? sender_host_address : key, domain);
+ }
+ } /* Continue with next domain */
+
+return FAIL;
+}
+
+/* End of verify.c */
git://git.exim.org / users / jgh / exim.git / blobdiff