1 /* $NetBSD: resolve.c,v 1.1.1.4 2013/01/02 18:59:10 tron Exp $ */ 2 3 /*++ 4 /* NAME 5 /* resolve 3 6 /* SUMMARY 7 /* mail address resolver 8 /* SYNOPSIS 9 /* #include "trivial-rewrite.h" 10 /* 11 /* void resolve_init(void) 12 /* 13 /* void resolve_proto(context, stream) 14 /* RES_CONTEXT *context; 15 /* VSTREAM *stream; 16 /* DESCRIPTION 17 /* This module implements the trivial address resolving engine. 18 /* It distinguishes between local and remote mail, and optionally 19 /* consults one or more transport tables that map a destination 20 /* to a transport, nexthop pair. 21 /* 22 /* resolve_init() initializes data structures that are private 23 /* to this module. It should be called once before using the 24 /* actual resolver routines. 25 /* 26 /* resolve_proto() implements the client-server protocol: 27 /* read one address in FQDN form, reply with a (transport, 28 /* nexthop, internalized recipient) triple. 29 /* STANDARDS 30 /* DIAGNOSTICS 31 /* Problems and transactions are logged to the syslog daemon. 32 /* BUGS 33 /* SEE ALSO 34 /* LICENSE 35 /* .ad 36 /* .fi 37 /* The Secure Mailer license must be distributed with this software. 38 /* AUTHOR(S) 39 /* Wietse Venema 40 /* IBM T.J. Watson Research 41 /* P.O. Box 704 42 /* Yorktown Heights, NY 10598, USA 43 /*--*/ 44 45 /* System library. */ 46 47 #include <sys_defs.h> 48 #include <stdlib.h> 49 #include <string.h> 50 51 #ifdef STRCASECMP_IN_STRINGS_H 52 #include <strings.h> 53 #endif 54 55 /* Utility library. */ 56 57 #include <msg.h> 58 #include <vstring.h> 59 #include <vstream.h> 60 #include <vstring_vstream.h> 61 #include <split_at.h> 62 #include <valid_hostname.h> 63 #include <stringops.h> 64 #include <mymalloc.h> 65 66 /* Global library. */ 67 68 #include <mail_params.h> 69 #include <mail_proto.h> 70 #include <resolve_local.h> 71 #include <mail_conf.h> 72 #include <quote_822_local.h> 73 #include <tok822.h> 74 #include <domain_list.h> 75 #include <string_list.h> 76 #include <match_parent_style.h> 77 #include <maps.h> 78 #include <mail_addr_find.h> 79 #include <valid_mailhost_addr.h> 80 81 /* Application-specific. */ 82 83 #include "trivial-rewrite.h" 84 #include "transport.h" 85 86 /* 87 * The job of the address resolver is to map one recipient address to a 88 * triple of (channel, nexthop, recipient). The channel is the name of the 89 * delivery service specified in master.cf, the nexthop is (usually) a 90 * description of the next host to deliver to, and recipient is the final 91 * recipient address. The latter may differ from the input address as the 92 * result of stripping multiple layers of sender-specified routing. 93 * 94 * Addresses are resolved by their domain name. Known domain names are 95 * categorized into classes: local, virtual alias, virtual mailbox, relay, 96 * and everything else. Finding the address domain class is a matter of 97 * table lookups. 98 * 99 * Different address domain classes generally use different delivery channels, 100 * and may use class dependent ways to arrive at the corresponding nexthop 101 * information. With classes that do final delivery, the nexthop is 102 * typically the local machine hostname. 103 * 104 * The transport lookup table provides a means to override the domain class 105 * channel and/or nexhop information for specific recipients or for entire 106 * domain hierarchies. 107 * 108 * This works well in the general case. The only bug in this approach is that 109 * the structure of the nexthop information is transport dependent. 110 * Typically, the nexthop specifies a hostname, hostname + TCP Port, or the 111 * pathname of a UNIX-domain socket. However, with the error transport the 112 * nexthop field contains free text with the reason for non-delivery. 113 * 114 * Therefore, a transport map entry that overrides the channel but not the 115 * nexthop information (or vice versa) may produce surprising results. In 116 * particular, the free text nexthop information for the error transport is 117 * likely to confuse regular delivery agents; and conversely, a hostname or 118 * socket pathname is not an adequate text as reason for non-delivery. 119 * 120 * In the code below, rcpt_domain specifies the domain name that we will use 121 * when the transport table specifies a non-default channel but no nexthop 122 * information (we use a generic text when that non-default channel is the 123 * error transport). 124 */ 125 126 #define STR vstring_str 127 128 /* 129 * Some of the lists that define the address domain classes. 130 */ 131 static DOMAIN_LIST *relay_domains; 132 static STRING_LIST *virt_alias_doms; 133 static STRING_LIST *virt_mailbox_doms; 134 135 static MAPS *relocated_maps; 136 137 /* resolve_addr - resolve address according to rule set */ 138 139 static void resolve_addr(RES_CONTEXT *rp, char *sender, char *addr, 140 VSTRING *channel, VSTRING *nexthop, 141 VSTRING *nextrcpt, int *flags) 142 { 143 const char *myname = "resolve_addr"; 144 VSTRING *addr_buf = vstring_alloc(100); 145 TOK822 *tree = 0; 146 TOK822 *saved_domain = 0; 147 TOK822 *domain = 0; 148 char *destination; 149 const char *blame = 0; 150 const char *rcpt_domain; 151 ssize_t addr_len; 152 ssize_t loop_count; 153 ssize_t loop_max; 154 char *local; 155 char *oper; 156 char *junk; 157 const char *relay; 158 const char *xport; 159 const char *sender_key; 160 int rc; 161 162 *flags = 0; 163 vstring_strcpy(channel, "CHANNEL NOT UPDATED"); 164 vstring_strcpy(nexthop, "NEXTHOP NOT UPDATED"); 165 vstring_strcpy(nextrcpt, "NEXTRCPT NOT UPDATED"); 166 167 /* 168 * The address is in internalized (unquoted) form. 169 * 170 * In an ideal world we would parse the externalized address form as given 171 * to us by the sender. 172 * 173 * However, in the real world we have to look for routing characters like 174 * %@! in the address local-part, even when that information is quoted 175 * due to the presence of special characters or whitespace. Although 176 * technically incorrect, this is needed to stop user@domain@domain relay 177 * attempts when forwarding mail to a Sendmail MX host. 178 * 179 * This suggests that we parse the address in internalized (unquoted) form. 180 * Unfortunately, if we do that, the unparser generates incorrect white 181 * space between adjacent non-operator tokens. Example: ``first last'' 182 * needs white space, but ``stuff[stuff]'' does not. This is is not a 183 * problem when unparsing the result from parsing externalized forms, 184 * because the parser/unparser were designed for valid externalized forms 185 * where ``stuff[stuff]'' does not happen. 186 * 187 * As a workaround we start with the quoted form and then dequote the 188 * local-part only where needed. This will do the right thing in most 189 * (but not all) cases. 190 */ 191 addr_len = strlen(addr); 192 quote_822_local(addr_buf, addr); 193 tree = tok822_scan_addr(vstring_str(addr_buf)); 194 195 /* 196 * The optimizer will eliminate tests that always fail, and will replace 197 * multiple expansions of this macro by a GOTO to a single instance. 198 */ 199 #define FREE_MEMORY_AND_RETURN { \ 200 if (saved_domain) \ 201 tok822_free_tree(saved_domain); \ 202 if(tree) \ 203 tok822_free_tree(tree); \ 204 if (addr_buf) \ 205 vstring_free(addr_buf); \ 206 return; \ 207 } 208 209 /* 210 * Preliminary resolver: strip off all instances of the local domain. 211 * Terminate when no destination domain is left over, or when the 212 * destination domain is remote. 213 * 214 * XXX To whom it may concern. If you change the resolver loop below, or 215 * quote_822_local.c, or tok822_parse.c, be sure to re-run the tests 216 * under "make resolve_clnt_test" in the global directory. 217 */ 218 #define RESOLVE_LOCAL(domain) \ 219 resolve_local(STR(tok822_internalize(addr_buf, domain, TOK822_STR_DEFL))) 220 221 for (loop_count = 0, loop_max = addr_len + 100; /* void */ ; loop_count++) { 222 223 /* 224 * XXX Should never happen, but if this happens with some 225 * pathological address, then that is not sufficient reason to 226 * disrupt the operation of an MTA. 227 */ 228 if (loop_count > loop_max) { 229 msg_warn("resolve_addr: <%s>: giving up after %ld iterations", 230 addr, (long) loop_count); 231 *flags |= RESOLVE_FLAG_FAIL; 232 FREE_MEMORY_AND_RETURN; 233 break; 234 } 235 236 /* 237 * Strip trailing dot at end of domain, but not dot-dot or at-dot. 238 * This merely makes diagnostics more accurate by leaving bogus 239 * addresses alone. 240 */ 241 if (tree->tail 242 && tree->tail->type == '.' 243 && tok822_rfind_type(tree->tail, '@') != 0 244 && tree->tail->prev->type != '.' 245 && tree->tail->prev->type != '@') 246 tok822_free_tree(tok822_sub_keep_before(tree, tree->tail)); 247 248 /* 249 * Strip trailing @. 250 */ 251 if (var_resolve_nulldom 252 && tree->tail 253 && tree->tail->type == '@') 254 tok822_free_tree(tok822_sub_keep_before(tree, tree->tail)); 255 256 /* 257 * Strip (and save) @domain if local. 258 * 259 * Grr. resolve_local() table lookups may fail. It may be OK for local 260 * file lookup code to abort upon failure, but with network-based 261 * tables it is preferable to return an error indication to the 262 * requestor. 263 */ 264 if ((domain = tok822_rfind_type(tree->tail, '@')) != 0) { 265 if (domain->next && (rc = RESOLVE_LOCAL(domain->next)) <= 0) { 266 if (rc < 0) { 267 *flags |= RESOLVE_FLAG_FAIL; 268 FREE_MEMORY_AND_RETURN; 269 } 270 break; 271 } 272 tok822_sub_keep_before(tree, domain); 273 if (saved_domain) 274 tok822_free_tree(saved_domain); 275 saved_domain = domain; 276 domain = 0; /* safety for future change */ 277 } 278 279 /* 280 * After stripping the local domain, if any, replace foo%bar by 281 * foo@bar, site!user by user@site, rewrite to canonical form, and 282 * retry. 283 */ 284 if (tok822_rfind_type(tree->tail, '@') 285 || (var_swap_bangpath && tok822_rfind_type(tree->tail, '!')) 286 || (var_percent_hack && tok822_rfind_type(tree->tail, '%'))) { 287 rewrite_tree(&local_context, tree); 288 continue; 289 } 290 291 /* 292 * If the local-part is a quoted string, crack it open when we're 293 * permitted to do so and look for routing operators. This is 294 * technically incorrect, but is needed to stop relaying problems. 295 * 296 * XXX Do another feeble attempt to keep local-part info quoted. 297 */ 298 if (var_resolve_dequoted 299 && tree->head && tree->head == tree->tail 300 && tree->head->type == TOK822_QSTRING 301 && ((oper = strrchr(local = STR(tree->head->vstr), '@')) != 0 302 || (var_percent_hack && (oper = strrchr(local, '%')) != 0) 303 || (var_swap_bangpath && (oper = strrchr(local, '!')) != 0))) { 304 if (*oper == '%') 305 *oper = '@'; 306 tok822_internalize(addr_buf, tree->head, TOK822_STR_DEFL); 307 if (*oper == '@') { 308 junk = mystrdup(STR(addr_buf)); 309 quote_822_local(addr_buf, junk); 310 myfree(junk); 311 } 312 tok822_free(tree->head); 313 tree->head = tok822_scan(STR(addr_buf), &tree->tail); 314 rewrite_tree(&local_context, tree); 315 continue; 316 } 317 318 /* 319 * An empty local-part or an empty quoted string local-part becomes 320 * the local MAILER-DAEMON, for consistency with our own From: 321 * message headers. 322 */ 323 if (tree->head && tree->head == tree->tail 324 && tree->head->type == TOK822_QSTRING 325 && VSTRING_LEN(tree->head->vstr) == 0) { 326 tok822_free(tree->head); 327 tree->head = 0; 328 } 329 /* XXX must be localpart only, not user@domain form. */ 330 if (tree->head == 0) 331 tree->head = tok822_scan(var_empty_addr, &tree->tail); 332 333 /* 334 * We're done. There are no domains left to strip off the address, 335 * and all null local-part information is sanitized. 336 */ 337 domain = 0; 338 break; 339 } 340 341 vstring_free(addr_buf); 342 addr_buf = 0; 343 344 /* 345 * Make sure the resolved envelope recipient has the user@domain form. If 346 * no domain was specified in the address, assume the local machine. See 347 * above for what happens with an empty address. 348 */ 349 if (domain == 0) { 350 if (saved_domain) { 351 tok822_sub_append(tree, saved_domain); 352 saved_domain = 0; 353 } else { 354 tok822_sub_append(tree, tok822_alloc('@', (char *) 0)); 355 tok822_sub_append(tree, tok822_scan(var_myhostname, (TOK822 **) 0)); 356 } 357 } 358 359 /* 360 * Transform the recipient address back to internal form. 361 * 362 * XXX This may produce incorrect results if we cracked open a quoted 363 * local-part with routing operators; see discussion above at the top of 364 * the big loop. 365 * 366 * XXX We explicitly disallow domain names in bare network address form. A 367 * network address destination should be formatted according to RFC 2821: 368 * it should be enclosed in [], and an IPv6 address should have an IPv6: 369 * prefix. 370 */ 371 tok822_internalize(nextrcpt, tree, TOK822_STR_DEFL); 372 rcpt_domain = strrchr(STR(nextrcpt), '@') + 1; 373 if (rcpt_domain == 0) 374 msg_panic("no @ in address: \"%s\"", STR(nextrcpt)); 375 if (*rcpt_domain == '[') { 376 if (!valid_mailhost_literal(rcpt_domain, DONT_GRIPE)) 377 *flags |= RESOLVE_FLAG_ERROR; 378 } else if (!valid_hostname(rcpt_domain, DONT_GRIPE)) { 379 if (var_resolve_num_dom && valid_hostaddr(rcpt_domain, DONT_GRIPE)) { 380 vstring_insert(nextrcpt, rcpt_domain - STR(nextrcpt), "[", 1); 381 vstring_strcat(nextrcpt, "]"); 382 rcpt_domain = strrchr(STR(nextrcpt), '@') + 1; 383 if ((rc = resolve_local(rcpt_domain)) > 0) /* XXX */ 384 domain = 0; 385 else if (rc < 0) { 386 *flags |= RESOLVE_FLAG_FAIL; 387 FREE_MEMORY_AND_RETURN; 388 } 389 } else { 390 *flags |= RESOLVE_FLAG_ERROR; 391 } 392 } 393 tok822_free_tree(tree); 394 tree = 0; 395 396 /* 397 * XXX Short-cut invalid address forms. 398 */ 399 if (*flags & RESOLVE_FLAG_ERROR) { 400 *flags |= RESOLVE_CLASS_DEFAULT; 401 FREE_MEMORY_AND_RETURN; 402 } 403 404 /* 405 * Recognize routing operators in the local-part, even when we do not 406 * recognize ! or % as valid routing operators locally. This is needed to 407 * prevent backup MX hosts from relaying third-party destinations through 408 * primary MX hosts, otherwise the backup host could end up on black 409 * lists. Ignore local swap_bangpath and percent_hack settings because we 410 * can't know how the next MX host is set up. 411 */ 412 if (strcmp(STR(nextrcpt) + strcspn(STR(nextrcpt), "@!%") + 1, rcpt_domain)) 413 *flags |= RESOLVE_FLAG_ROUTED; 414 415 /* 416 * With local, virtual, relay, or other non-local destinations, give the 417 * highest precedence to transport associated nexthop information. 418 * 419 * Otherwise, with relay or other non-local destinations, the relayhost 420 * setting overrides the recipient domain name, and the sender-dependent 421 * relayhost overrides both. 422 * 423 * XXX Nag if the recipient domain is listed in multiple domain lists. The 424 * result is implementation defined, and may break when internals change. 425 * 426 * For now, we distinguish only a fixed number of address classes. 427 * Eventually this may become extensible, so that new classes can be 428 * configured with their own domain list, delivery transport, and 429 * recipient table. 430 */ 431 #define STREQ(x,y) (strcmp((x), (y)) == 0) 432 433 if (domain != 0) { 434 435 /* 436 * Virtual alias domain. 437 */ 438 if (virt_alias_doms 439 && string_list_match(virt_alias_doms, rcpt_domain)) { 440 if (var_helpful_warnings) { 441 if (virt_mailbox_doms 442 && string_list_match(virt_mailbox_doms, rcpt_domain)) 443 msg_warn("do not list domain %s in BOTH %s and %s", 444 rcpt_domain, VAR_VIRT_ALIAS_DOMS, 445 VAR_VIRT_MAILBOX_DOMS); 446 if (relay_domains 447 && domain_list_match(relay_domains, rcpt_domain)) 448 msg_warn("do not list domain %s in BOTH %s and %s", 449 rcpt_domain, VAR_VIRT_ALIAS_DOMS, 450 VAR_RELAY_DOMAINS); 451 #if 0 452 if (strcasecmp(rcpt_domain, var_myorigin) == 0) 453 msg_warn("do not list $%s (%s) in %s", 454 VAR_MYORIGIN, var_myorigin, VAR_VIRT_ALIAS_DOMS); 455 #endif 456 } 457 vstring_strcpy(channel, MAIL_SERVICE_ERROR); 458 vstring_sprintf(nexthop, "User unknown%s", 459 var_show_unk_rcpt_table ? 460 " in virtual alias table" : ""); 461 *flags |= RESOLVE_CLASS_ALIAS; 462 } else if (virt_alias_doms && virt_alias_doms->error != 0) { 463 msg_warn("%s lookup failure", VAR_VIRT_ALIAS_DOMS); 464 *flags |= RESOLVE_FLAG_FAIL; 465 FREE_MEMORY_AND_RETURN; 466 } 467 468 /* 469 * Virtual mailbox domain. 470 */ 471 else if (virt_mailbox_doms 472 && string_list_match(virt_mailbox_doms, rcpt_domain)) { 473 if (var_helpful_warnings) { 474 if (relay_domains 475 && domain_list_match(relay_domains, rcpt_domain)) 476 msg_warn("do not list domain %s in BOTH %s and %s", 477 rcpt_domain, VAR_VIRT_MAILBOX_DOMS, 478 VAR_RELAY_DOMAINS); 479 } 480 vstring_strcpy(channel, RES_PARAM_VALUE(rp->virt_transport)); 481 vstring_strcpy(nexthop, rcpt_domain); 482 blame = rp->virt_transport_name; 483 *flags |= RESOLVE_CLASS_VIRTUAL; 484 } else if (virt_mailbox_doms && virt_mailbox_doms->error != 0) { 485 msg_warn("%s lookup failure", VAR_VIRT_MAILBOX_DOMS); 486 *flags |= RESOLVE_FLAG_FAIL; 487 FREE_MEMORY_AND_RETURN; 488 } else { 489 490 /* 491 * Off-host relay destination. 492 */ 493 if (relay_domains 494 && domain_list_match(relay_domains, rcpt_domain)) { 495 vstring_strcpy(channel, RES_PARAM_VALUE(rp->relay_transport)); 496 blame = rp->relay_transport_name; 497 *flags |= RESOLVE_CLASS_RELAY; 498 } else if (relay_domains && relay_domains->error != 0) { 499 msg_warn("%s lookup failure", VAR_RELAY_DOMAINS); 500 *flags |= RESOLVE_FLAG_FAIL; 501 FREE_MEMORY_AND_RETURN; 502 } 503 504 /* 505 * Other off-host destination. 506 */ 507 else { 508 if (rp->snd_def_xp_info 509 && (xport = mail_addr_find(rp->snd_def_xp_info, 510 sender_key = (*sender ? sender : 511 var_null_def_xport_maps_key), 512 (char **) 0)) != 0) { 513 if (*xport == 0) { 514 msg_warn("%s: ignoring null lookup result for %s", 515 rp->snd_def_xp_maps_name, sender_key); 516 xport = "DUNNO"; 517 } 518 vstring_strcpy(channel, strcasecmp(xport, "DUNNO") == 0 ? 519 RES_PARAM_VALUE(rp->def_transport) : xport); 520 blame = rp->snd_def_xp_maps_name; 521 } else if (rp->snd_def_xp_info 522 && rp->snd_def_xp_info->error != 0) { 523 msg_warn("%s lookup failure", rp->snd_def_xp_maps_name); 524 *flags |= RESOLVE_FLAG_FAIL; 525 FREE_MEMORY_AND_RETURN; 526 } else { 527 vstring_strcpy(channel, RES_PARAM_VALUE(rp->def_transport)); 528 blame = rp->def_transport_name; 529 } 530 *flags |= RESOLVE_CLASS_DEFAULT; 531 } 532 533 /* 534 * With off-host delivery, sender-dependent or global relayhost 535 * override the recipient domain. 536 */ 537 if (rp->snd_relay_info 538 && (relay = mail_addr_find(rp->snd_relay_info, 539 sender_key = (*sender ? sender : 540 var_null_relay_maps_key), 541 (char **) 0)) != 0) { 542 if (*relay == 0) { 543 msg_warn("%s: ignoring null lookup result for %s", 544 rp->snd_relay_maps_name, sender_key); 545 relay = "DUNNO"; 546 } 547 vstring_strcpy(nexthop, strcasecmp(relay, "DUNNO") == 0 ? 548 rcpt_domain : relay); 549 } else if (rp->snd_relay_info 550 && rp->snd_relay_info->error != 0) { 551 msg_warn("%s lookup failure", rp->snd_relay_maps_name); 552 *flags |= RESOLVE_FLAG_FAIL; 553 FREE_MEMORY_AND_RETURN; 554 } else if (*RES_PARAM_VALUE(rp->relayhost)) 555 vstring_strcpy(nexthop, RES_PARAM_VALUE(rp->relayhost)); 556 else 557 vstring_strcpy(nexthop, rcpt_domain); 558 } 559 } 560 561 /* 562 * Local delivery. 563 * 564 * XXX Nag if the domain is listed in multiple domain lists. The effect is 565 * implementation defined, and may break when internals change. 566 */ 567 else { 568 if (var_helpful_warnings) { 569 if (virt_alias_doms 570 && string_list_match(virt_alias_doms, rcpt_domain)) 571 msg_warn("do not list domain %s in BOTH %s and %s", 572 rcpt_domain, VAR_MYDEST, VAR_VIRT_ALIAS_DOMS); 573 if (virt_mailbox_doms 574 && string_list_match(virt_mailbox_doms, rcpt_domain)) 575 msg_warn("do not list domain %s in BOTH %s and %s", 576 rcpt_domain, VAR_MYDEST, VAR_VIRT_MAILBOX_DOMS); 577 } 578 vstring_strcpy(channel, RES_PARAM_VALUE(rp->local_transport)); 579 vstring_strcpy(nexthop, rcpt_domain); 580 blame = rp->local_transport_name; 581 *flags |= RESOLVE_CLASS_LOCAL; 582 } 583 584 /* 585 * An explicit main.cf transport:nexthop setting overrides the nexthop. 586 * 587 * XXX We depend on this mechanism to enforce per-recipient concurrencies 588 * for local recipients. With "local_transport = local:$myhostname" we 589 * force mail for any domain in $mydestination/${proxy,inet}_interfaces 590 * to share the same queue. 591 */ 592 if ((destination = split_at(STR(channel), ':')) != 0 && *destination) 593 vstring_strcpy(nexthop, destination); 594 595 /* 596 * Sanity checks. 597 */ 598 if (*STR(channel) == 0) { 599 if (blame == 0) 600 msg_panic("%s: null blame", myname); 601 msg_warn("file %s/%s: parameter %s: null transport is not allowed", 602 var_config_dir, MAIN_CONF_FILE, blame); 603 *flags |= RESOLVE_FLAG_FAIL; 604 FREE_MEMORY_AND_RETURN; 605 } 606 if (*STR(nexthop) == 0) 607 msg_panic("%s: null nexthop", myname); 608 609 /* 610 * The transport map can selectively override any transport and/or 611 * nexthop host info that is set up above. Unfortunately, the syntax for 612 * nexthop information is transport specific. We therefore need sane and 613 * intuitive semantics for transport map entries that specify a channel 614 * but no nexthop. 615 * 616 * With non-error transports, the initial nexthop information is the 617 * recipient domain. However, specific main.cf transport definitions may 618 * specify a transport-specific destination, such as a host + TCP socket, 619 * or the pathname of a UNIX-domain socket. With less precedence than 620 * main.cf transport definitions, a main.cf relayhost definition may also 621 * override nexthop information for off-host deliveries. 622 * 623 * With the error transport, the nexthop information is free text that 624 * specifies the reason for non-delivery. 625 * 626 * Because nexthop syntax is transport specific we reset the nexthop 627 * information to the recipient domain when the transport table specifies 628 * a transport without also specifying the nexthop information. 629 * 630 * Subtle note: reset nexthop even when the transport table does not change 631 * the transport. Otherwise it is hard to get rid of main.cf specified 632 * nexthop information. 633 * 634 * XXX Don't override the virtual alias class (error:User unknown) result. 635 */ 636 if (rp->transport_info && !(*flags & RESOLVE_CLASS_ALIAS)) { 637 if (transport_lookup(rp->transport_info, STR(nextrcpt), 638 rcpt_domain, channel, nexthop) == 0 639 && rp->transport_info->transport_path->error != 0) { 640 msg_warn("%s lookup failure", rp->transport_maps_name); 641 *flags |= RESOLVE_FLAG_FAIL; 642 FREE_MEMORY_AND_RETURN; 643 } 644 } 645 646 /* 647 * Bounce recipients that have moved, regardless of domain address class. 648 * We do this last, in anticipation of transport maps that can override 649 * the recipient address. 650 * 651 * The downside of not doing this in delivery agents is that this table has 652 * no effect on local alias expansion results. Such mail will have to 653 * make almost an entire iteration through the mail system. 654 */ 655 #define IGNORE_ADDR_EXTENSION ((char **) 0) 656 657 if (relocated_maps != 0) { 658 const char *newloc; 659 660 if ((newloc = mail_addr_find(relocated_maps, STR(nextrcpt), 661 IGNORE_ADDR_EXTENSION)) != 0) { 662 vstring_strcpy(channel, MAIL_SERVICE_ERROR); 663 /* 5.1.6 is the closest match, but not perfect. */ 664 vstring_sprintf(nexthop, "5.1.6 User has moved to %s", newloc); 665 } else if (relocated_maps->error != 0) { 666 msg_warn("%s lookup failure", VAR_RELOCATED_MAPS); 667 *flags |= RESOLVE_FLAG_FAIL; 668 FREE_MEMORY_AND_RETURN; 669 } 670 } 671 672 /* 673 * Bounce recipient addresses that start with `-'. External commands may 674 * misinterpret such addresses as command-line options. 675 * 676 * In theory I could say people should always carefully set up their 677 * master.cf pipe mailer entries with `--' before the first non-option 678 * argument, but mistakes will happen regardless. 679 * 680 * Therefore the protection is put in place here, where it cannot be 681 * bypassed. 682 */ 683 if (var_allow_min_user == 0 && STR(nextrcpt)[0] == '-') { 684 *flags |= RESOLVE_FLAG_ERROR; 685 FREE_MEMORY_AND_RETURN; 686 } 687 688 /* 689 * Clean up. 690 */ 691 FREE_MEMORY_AND_RETURN; 692 } 693 694 /* Static, so they can be used by the network protocol interface only. */ 695 696 static VSTRING *channel; 697 static VSTRING *nexthop; 698 static VSTRING *nextrcpt; 699 static VSTRING *query; 700 static VSTRING *sender; 701 702 /* resolve_proto - read request and send reply */ 703 704 int resolve_proto(RES_CONTEXT *context, VSTREAM *stream) 705 { 706 int flags; 707 708 if (attr_scan(stream, ATTR_FLAG_STRICT, 709 ATTR_TYPE_STR, MAIL_ATTR_SENDER, sender, 710 ATTR_TYPE_STR, MAIL_ATTR_ADDR, query, 711 ATTR_TYPE_END) != 2) 712 return (-1); 713 714 resolve_addr(context, STR(sender), STR(query), 715 channel, nexthop, nextrcpt, &flags); 716 717 if (msg_verbose) 718 msg_info("`%s' -> `%s' -> (`%s' `%s' `%s' `%d')", 719 STR(sender), STR(query), STR(channel), 720 STR(nexthop), STR(nextrcpt), flags); 721 722 attr_print(stream, ATTR_FLAG_NONE, 723 ATTR_TYPE_INT, MAIL_ATTR_FLAGS, server_flags, 724 ATTR_TYPE_STR, MAIL_ATTR_TRANSPORT, STR(channel), 725 ATTR_TYPE_STR, MAIL_ATTR_NEXTHOP, STR(nexthop), 726 ATTR_TYPE_STR, MAIL_ATTR_RECIP, STR(nextrcpt), 727 ATTR_TYPE_INT, MAIL_ATTR_FLAGS, flags, 728 ATTR_TYPE_END); 729 730 if (vstream_fflush(stream) != 0) { 731 msg_warn("write resolver reply: %m"); 732 return (-1); 733 } 734 return (0); 735 } 736 737 /* resolve_init - module initializations */ 738 739 void resolve_init(void) 740 { 741 sender = vstring_alloc(100); 742 query = vstring_alloc(100); 743 channel = vstring_alloc(100); 744 nexthop = vstring_alloc(100); 745 nextrcpt = vstring_alloc(100); 746 747 if (*var_virt_alias_doms) 748 virt_alias_doms = 749 string_list_init(MATCH_FLAG_RETURN, var_virt_alias_doms); 750 751 if (*var_virt_mailbox_doms) 752 virt_mailbox_doms = 753 string_list_init(MATCH_FLAG_RETURN, var_virt_mailbox_doms); 754 755 if (*var_relay_domains) 756 relay_domains = 757 domain_list_init(MATCH_FLAG_RETURN 758 | match_parent_style(VAR_RELAY_DOMAINS), 759 var_relay_domains); 760 761 if (*var_relocated_maps) 762 relocated_maps = 763 maps_create(VAR_RELOCATED_MAPS, var_relocated_maps, 764 DICT_FLAG_LOCK | DICT_FLAG_FOLD_FIX); 765 } 766