X-Git-Url: https://git.exim.org/exim.git/blobdiff_plain/2c7db3f5d15a2f085d15ea0e8c22b826ed928721..8e669ac162fe3b1040297f1d021de10778dce9d9:/src/src/verify.c diff --git a/src/src/verify.c b/src/src/verify.c index 45a4c819d..458f4d978 100644 --- a/src/src/verify.c +++ b/src/src/verify.c @@ -1,10 +1,10 @@ -/* $Cambridge: exim/src/src/verify.c,v 1.3 2004/11/05 16:53:28 ph10 Exp $ */ +/* $Cambridge: exim/src/src/verify.c,v 1.15 2005/02/17 11:58:26 ph10 Exp $ */ /************************************************* * Exim - an Internet mail transport agent * *************************************************/ -/* Copyright (c) University of Cambridge 1995 - 2004 */ +/* Copyright (c) University of Cambridge 1995 - 2005 */ /* See the file NOTICE for conditions of use and distribution. */ /* Functions concerned with verifying things. The original code for callout @@ -139,7 +139,7 @@ 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, + int callout, int callout_overall, int callout_connect, int options, uschar *se_mailfrom, uschar *pm_mailfrom) { BOOL is_recipient = (options & vopt_is_recipient) != 0; @@ -151,7 +151,7 @@ BOOL done = FALSE; uschar *address_key; uschar *from_address; uschar *random_local_part = NULL; -uschar **failure_ptr = is_recipient? +uschar **failure_ptr = is_recipient? &recipient_verify_failure : &sender_verify_failure; open_db dbblock; open_db *dbm_file = NULL; @@ -238,7 +238,7 @@ if (dbm_file != NULL) setflag(addr, af_verify_nsfail); addr->user_message = US"(result of an earlier callout reused)."; yield = FAIL; - *failure_ptr = US"mail"; + *failure_ptr = US"mail"; goto END_CALLOUT; } @@ -285,7 +285,7 @@ if (dbm_file != NULL) debug_printf("callout cache: domain does not accept " "RCPT TO:\n"); yield = FAIL; - *failure_ptr = US"postmaster"; + *failure_ptr = US"postmaster"; setflag(addr, af_verify_pmfail); addr->user_message = US"(result of earlier verification reused)."; goto END_CALLOUT; @@ -334,7 +334,7 @@ if (dbm_file != NULL) 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"; + *failure_ptr = US"recipient"; yield = FAIL; } goto END_CALLOUT; @@ -377,6 +377,7 @@ for (host = host_list; host != NULL && !done; host = host->next) smtp_outblock outblock; int host_af; int port = 25; + BOOL send_quit = TRUE; uschar *helo = US"HELO"; uschar *interface = NULL; /* Outgoing interface to use; NULL => any */ uschar inbuffer[4096]; @@ -481,7 +482,7 @@ for (host = host_list; host != NULL && !done; host = host->next) if (!done) { - *failure_ptr = US"mail"; + *failure_ptr = US"mail"; if (errno == 0 && responsebuffer[0] == '5') { setflag(addr, af_verify_nsfail); @@ -557,9 +558,9 @@ for (host = host_list; host != NULL && !done; host = host->next) new_address_record.result = ccache_accept; else if (errno == 0 && responsebuffer[0] == '5') { - *failure_ptr = US"recipient"; + *failure_ptr = US"recipient"; new_address_record.result = ccache_reject; - } + } /* Do postmaster check if requested */ @@ -586,7 +587,7 @@ for (host = host_list; host != NULL && !done; host = host->next) new_domain_record.postmaster_result = ccache_accept; else if (errno == 0 && responsebuffer[0] == '5') { - *failure_ptr = US"postmaster"; + *failure_ptr = US"postmaster"; setflag(addr, af_verify_pmfail); new_domain_record.postmaster_result = ccache_reject; } @@ -609,6 +610,7 @@ for (host = host_list; host != NULL && !done; host = host->next) if (errno == ETIMEDOUT) { HDEBUG(D_verify) debug_printf("SMTP timeout\n"); + send_quit = FALSE; } else if (errno == 0) { @@ -637,7 +639,7 @@ for (host = host_list; host != NULL && !done; host = host->next) /* End the SMTP conversation and close the connection. */ - (void)smtp_write_command(&outblock, FALSE, "QUIT\r\n"); + if (send_quit) (void)smtp_write_command(&outblock, FALSE, "QUIT\r\n"); close(inblock.sock); } /* Loop through all hosts, while !done */ @@ -797,7 +799,7 @@ Arguments: 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 + 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 @@ -813,7 +815,7 @@ Returns: OK address verified int verify_address(address_item *vaddr, FILE *f, int options, int callout, - int callout_overall, int callout_connect, uschar *se_mailfrom, + int callout_overall, int callout_connect, uschar *se_mailfrom, uschar *pm_mailfrom, BOOL *routed) { BOOL allok = TRUE; @@ -830,7 +832,7 @@ address_item *addr_new = NULL; address_item *addr_remote = NULL; address_item *addr_local = NULL; address_item *addr_succeed = NULL; -uschar **failure_ptr = is_recipient? +uschar **failure_ptr = is_recipient? &recipient_verify_failure : &sender_verify_failure; uschar *ko_prefix, *cr; uschar *address = vaddr->address; @@ -861,7 +863,7 @@ if (parse_find_at(address) == NULL) if (f != NULL) fprintf(f, "%sA domain is required for \"%s\"%s\n", ko_prefix, address, cr); - *failure_ptr = US"qualify"; + *failure_ptr = US"qualify"; return FAIL; } address = rewrite_address_qualify(address, is_recipient); @@ -1037,15 +1039,20 @@ while (addr_new != NULL) else { uschar *canonical_name; - host_item *host; + 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. */ + 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. */ - for (host = host_list; host != NULL; host = host->next) + for (host = host_list; host != NULL; host = nexthost) { - if (tf.gethostbyname || string_is_ip_address(host->name, NULL)) + nexthost = host->next; + if (tf.gethostbyname || + string_is_ip_address(host->name, NULL) > 0) (void)host_find_byname(host, NULL, &canonical_name, TRUE); else { @@ -1060,7 +1067,7 @@ while (addr_new != NULL) } } - /* Can only do a callout if we have at least one host! If the callout + /* 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 != NULL) @@ -1085,10 +1092,10 @@ while (addr_new != NULL) } } } - + /* Otherwise, any failure is a routing failure */ - - else *failure_ptr = US"route"; + + 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 @@ -1276,10 +1283,10 @@ else for (addr_list = addr_local, i = 0; i < 2; addr_list = addr_remote, i++) } } -/* Will be DEFER or FAIL if any one address has, only for full_info (which is +/* Will be DEFER or FAIL if any one address has, only for full_info (which is the -bv or -bt case). */ -return yield; +return yield; } @@ -1454,10 +1461,11 @@ Arguments: 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) + 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. @@ -1468,8 +1476,8 @@ Returns: result of the verification attempt: OK, FAIL, or DEFER; 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 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 }; int yield = FAIL; @@ -1550,7 +1558,7 @@ for (i = 0; i < 3; i++) } } - /* Else go ahead with the sender verification. But is isn't *the* + /* 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. */ @@ -1558,7 +1566,7 @@ for (i = 0; i < 3; i++) { vaddr = deliver_make_addr(address, FALSE); new_ok = verify_address(vaddr, NULL, options | vopt_fake_sender, - callout, callout_overall, callout_connect, se_mailfrom, + callout, callout_overall, callout_connect, se_mailfrom, pm_mailfrom, NULL); } } @@ -1568,11 +1576,15 @@ for (i = 0; i < 3; i++) 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) + if (new_ok != OK) { - *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); + *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", + endname - h->text, h->text, vaddr->address, vaddr->message); + } } /* Success or defer */ @@ -1826,7 +1838,7 @@ if (*ss == '@') /* 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)) +if (string_is_ip_address(ss, &maskoffset) > 0) return (host_is_in_net(cb->host_address, ss, maskoffset)? OK : FAIL); /* If the item is of the form net[n]-lookup; then it is a lookup on @@ -1862,7 +1874,8 @@ if (Ustrncmp(ss, "net", 3) == 0 && (semicolon = Ustrchr(ss, ';')) != NULL) /* 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. */ + appropriately, and reconverted to text form, with the mask appended. + For IPv6 addresses, specify dot separators instead of colons. */ if (mac_islookup(search_type, lookup_querystyle)) { @@ -1873,7 +1886,7 @@ if (Ustrncmp(ss, "net", 3) == 0 && (semicolon = Ustrchr(ss, ';')) != NULL) { insize = host_aton(cb->host_address, incoming); host_mask(insize, incoming, mlen); - (void)host_nmtoa(insize, incoming, mlen, buffer); + (void)host_nmtoa(insize, incoming, mlen, buffer, '.'); key = buffer; filename = semicolon + 1; } @@ -2050,7 +2063,9 @@ int verify_check_this_host(uschar **listptr, unsigned int *cache_bits, uschar *host_name, uschar *host_address, uschar **valueptr) { +int rc; unsigned int *local_cache_bits = cache_bits; +uschar *save_host_address = deliver_host_address; check_host_block cb; cb.host_name = host_name; cb.host_address = host_address; @@ -2064,9 +2079,26 @@ 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); +/* 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; } @@ -2159,6 +2191,254 @@ else +/************************************************* +* Perform a single dnsbl lookup * +*************************************************/ + +/* This function is called from verify_check_dnsbl() below. + +Arguments: + domain the outer dnsbl domain (for debug message) + keydomain the current keydomain (for debug message) + query the domain to be looked up + iplist the list of matching IP addresses + bitmask true if bitmask matching is wanted + invert_result true if result to be inverted + defer_return what to return for a defer + +Returns: OK if lookup succeeded + FAIL if not +*/ + +static int +one_check_dnsbl(uschar *domain, uschar *keydomain, uschar *query, + uschar *iplist, BOOL bitmask, BOOL invert_result, int defer_return) +{ +dns_answer dnsa; +dns_scan dnss; +tree_node *t; +dnsbl_cache_block *cb; +int old_pool = store_pool; + +/* 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; + + /* 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); + } + return FAIL; + } + } + + /* 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; + } + } + } + + 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 * *************************************************/ @@ -2203,7 +2483,6 @@ 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; @@ -2216,18 +2495,19 @@ uschar revadd[128]; /* Long enough for IPv6 address */ revadd[0] = 0; +/* In case this is the first time the DNS resolver is being used. */ + +dns_init(FALSE, FALSE); + /* Loop through all the domains supplied, until something matches */ while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL) { + int rc; 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); @@ -2286,251 +2566,87 @@ while ((domain = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL } } - /* Construct the query by adding the domain onto either the sending host - address, or the given key string. */ + /* 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 (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) + if (!frc) { - 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); - } - } - } + log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long " + "(ignored): %s...", query); + continue; + } - /* 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. */ + rc = one_check_dnsbl(domain, sender_host_address, query, iplist, bitmask, + invert_result, defer_return); - if (cb->rhs == NULL) cb->rc = DNS_NODATA; + if (rc == OK) + { + dnslist_domain = string_copy(domain); + HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n", + sender_host_address, domain); } - store_pool = old_pool; + if (rc != FAIL) return rc; /* OK or DEFER */ } - /* Previous lookup was cached */ + /* If there is a key string, it can be a list of domains or IP addresses to + be concatenated with the main domain. */ 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. */ + int keysep = 0; + BOOL defer = FALSE; + uschar *keydomain; + uschar keybuffer[256]; - 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) + while ((keydomain = string_nextinlist(&key, &keysep, keybuffer, + sizeof(keybuffer))) != NULL) { - int ipsep = ','; - uschar ip[46]; - uschar *ptr = iplist; - - while (string_nextinlist(&ptr, &ipsep, ip, sizeof(ip)) != NULL) + if (string_is_ip_address(keydomain, NULL) > 0) { - /* 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; + uschar keyrevadd[128]; + invert_address(keyrevadd, keydomain); + frc = string_format(query, sizeof(query), "%s%s", keyrevadd, domain); } - - /* 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)) + else { - 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 */ + frc = string_format(query, sizeof(query), "%s.%s", keydomain, 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) + if (!frc) { - 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; - } + log_write(0, LOG_MAIN|LOG_PANIC, "dnslist query is too long " + "(ignored): %s...", query); + continue; } - } - - 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; - } + rc = one_check_dnsbl(domain, keydomain, query, iplist, bitmask, + invert_result, defer_return); - /* There was a problem with the DNS lookup */ + if (rc == OK) + { + dnslist_domain = string_copy(domain); + HDEBUG(D_dnsbl) debug_printf("=> that means %s is listed at %s\n", + keydomain, domain); + return OK; + } - 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; - } + /* 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. */ - /* No entry was found in the DNS; continue for next domain */ + if (rc == DEFER) defer = TRUE; + } /* continue with next keystring domain/address */ - 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); + if (defer) return DEFER; } - } /* Continue with next domain */ + } /* continue with next dnsdb outer domain */ return FAIL; }