1 /* 2 * Copyright (c) 2000-2004 Sendmail, Inc. and its suppliers. 3 * All rights reserved. 4 * 5 * By using this file, you agree to the terms and conditions set 6 * forth in the LICENSE file which can be found at the top level of 7 * the sendmail distribution. 8 * 9 */ 10 11 /* 12 * Copyright (c) 1995, 1996, 1997, 1998, 1999 Kungliga Tekniska H�gskolan 13 * (Royal Institute of Technology, Stockholm, Sweden). 14 * All rights reserved. 15 * 16 * Redistribution and use in source and binary forms, with or without 17 * modification, are permitted provided that the following conditions 18 * are met: 19 * 20 * 1. Redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer. 22 * 23 * 2. Redistributions in binary form must reproduce the above copyright 24 * notice, this list of conditions and the following disclaimer in the 25 * documentation and/or other materials provided with the distribution. 26 * 27 * 3. Neither the name of the Institute nor the names of its contributors 28 * may be used to endorse or promote products derived from this software 29 * without specific prior written permission. 30 * 31 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 32 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 33 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 34 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 35 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 36 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 37 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 39 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 40 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 41 * SUCH DAMAGE. 42 */ 43 44 #pragma ident "%Z%%M% %I% %E% SMI" 45 46 #include <sendmail.h> 47 #if DNSMAP 48 # if NAMED_BIND 49 # include "sm_resolve.h" 50 51 SM_RCSID("$Id: sm_resolve.c,v 8.34 2006/08/15 23:24:58 ca Exp $") 52 53 static struct stot 54 { 55 const char *st_name; 56 int st_type; 57 } stot[] = 58 { 59 # if NETINET 60 { "A", T_A }, 61 # endif /* NETINET */ 62 # if NETINET6 63 { "AAAA", T_AAAA }, 64 # endif /* NETINET6 */ 65 { "NS", T_NS }, 66 { "CNAME", T_CNAME }, 67 { "PTR", T_PTR }, 68 { "MX", T_MX }, 69 { "TXT", T_TXT }, 70 { "AFSDB", T_AFSDB }, 71 { "SRV", T_SRV }, 72 { NULL, 0 } 73 }; 74 75 static DNS_REPLY_T *parse_dns_reply __P((unsigned char *, int)); 76 77 /* 78 ** DNS_STRING_TO_TYPE -- convert resource record name into type 79 ** 80 ** Parameters: 81 ** name -- name of resource record type 82 ** 83 ** Returns: 84 ** type if succeeded. 85 ** -1 otherwise. 86 */ 87 88 int 89 dns_string_to_type(name) 90 const char *name; 91 { 92 struct stot *p = stot; 93 94 for (p = stot; p->st_name != NULL; p++) 95 if (sm_strcasecmp(name, p->st_name) == 0) 96 return p->st_type; 97 return -1; 98 } 99 100 /* 101 ** DNS_TYPE_TO_STRING -- convert resource record type into name 102 ** 103 ** Parameters: 104 ** type -- resource record type 105 ** 106 ** Returns: 107 ** name if succeeded. 108 ** NULL otherwise. 109 */ 110 111 const char * 112 dns_type_to_string(type) 113 int type; 114 { 115 struct stot *p = stot; 116 117 for (p = stot; p->st_name != NULL; p++) 118 if (type == p->st_type) 119 return p->st_name; 120 return NULL; 121 } 122 123 /* 124 ** DNS_FREE_DATA -- free all components of a DNS_REPLY_T 125 ** 126 ** Parameters: 127 ** r -- pointer to DNS_REPLY_T 128 ** 129 ** Returns: 130 ** none. 131 */ 132 133 void 134 dns_free_data(r) 135 DNS_REPLY_T *r; 136 { 137 RESOURCE_RECORD_T *rr; 138 139 if (r->dns_r_q.dns_q_domain != NULL) 140 sm_free(r->dns_r_q.dns_q_domain); 141 for (rr = r->dns_r_head; rr != NULL; ) 142 { 143 RESOURCE_RECORD_T *tmp = rr; 144 145 if (rr->rr_domain != NULL) 146 sm_free(rr->rr_domain); 147 if (rr->rr_u.rr_data != NULL) 148 sm_free(rr->rr_u.rr_data); 149 rr = rr->rr_next; 150 sm_free(tmp); 151 } 152 sm_free(r); 153 } 154 155 /* 156 ** PARSE_DNS_REPLY -- parse DNS reply data. 157 ** 158 ** Parameters: 159 ** data -- pointer to dns data 160 ** len -- len of data 161 ** 162 ** Returns: 163 ** pointer to DNS_REPLY_T if succeeded. 164 ** NULL otherwise. 165 */ 166 167 static DNS_REPLY_T * 168 parse_dns_reply(data, len) 169 unsigned char *data; 170 int len; 171 { 172 unsigned char *p; 173 int status; 174 size_t l; 175 char host[MAXHOSTNAMELEN]; 176 DNS_REPLY_T *r; 177 RESOURCE_RECORD_T **rr; 178 179 r = (DNS_REPLY_T *) sm_malloc(sizeof(*r)); 180 if (r == NULL) 181 return NULL; 182 memset(r, 0, sizeof(*r)); 183 184 p = data; 185 186 /* doesn't work on Crays? */ 187 memcpy(&r->dns_r_h, p, sizeof(r->dns_r_h)); 188 p += sizeof(r->dns_r_h); 189 status = dn_expand(data, data + len, p, host, sizeof(host)); 190 if (status < 0) 191 { 192 dns_free_data(r); 193 return NULL; 194 } 195 r->dns_r_q.dns_q_domain = sm_strdup(host); 196 if (r->dns_r_q.dns_q_domain == NULL) 197 { 198 dns_free_data(r); 199 return NULL; 200 } 201 p += status; 202 GETSHORT(r->dns_r_q.dns_q_type, p); 203 GETSHORT(r->dns_r_q.dns_q_class, p); 204 rr = &r->dns_r_head; 205 while (p < data + len) 206 { 207 int type, class, ttl, size, txtlen; 208 209 status = dn_expand(data, data + len, p, host, sizeof(host)); 210 if (status < 0) 211 { 212 dns_free_data(r); 213 return NULL; 214 } 215 p += status; 216 GETSHORT(type, p); 217 GETSHORT(class, p); 218 GETLONG(ttl, p); 219 GETSHORT(size, p); 220 if (p + size > data + len) 221 { 222 /* 223 ** announced size of data exceeds length of 224 ** data paket: someone is cheating. 225 */ 226 227 if (LogLevel > 5) 228 sm_syslog(LOG_WARNING, NOQID, 229 "ERROR: DNS RDLENGTH=%d > data len=%d", 230 size, len - (p - data)); 231 dns_free_data(r); 232 return NULL; 233 } 234 *rr = (RESOURCE_RECORD_T *) sm_malloc(sizeof(**rr)); 235 if (*rr == NULL) 236 { 237 dns_free_data(r); 238 return NULL; 239 } 240 memset(*rr, 0, sizeof(**rr)); 241 (*rr)->rr_domain = sm_strdup(host); 242 if ((*rr)->rr_domain == NULL) 243 { 244 dns_free_data(r); 245 return NULL; 246 } 247 (*rr)->rr_type = type; 248 (*rr)->rr_class = class; 249 (*rr)->rr_ttl = ttl; 250 (*rr)->rr_size = size; 251 switch (type) 252 { 253 case T_NS: 254 case T_CNAME: 255 case T_PTR: 256 status = dn_expand(data, data + len, p, host, 257 sizeof(host)); 258 if (status < 0) 259 { 260 dns_free_data(r); 261 return NULL; 262 } 263 (*rr)->rr_u.rr_txt = sm_strdup(host); 264 if ((*rr)->rr_u.rr_txt == NULL) 265 { 266 dns_free_data(r); 267 return NULL; 268 } 269 break; 270 271 case T_MX: 272 case T_AFSDB: 273 status = dn_expand(data, data + len, p + 2, host, 274 sizeof(host)); 275 if (status < 0) 276 { 277 dns_free_data(r); 278 return NULL; 279 } 280 l = strlen(host) + 1; 281 (*rr)->rr_u.rr_mx = (MX_RECORD_T *) 282 sm_malloc(sizeof(*((*rr)->rr_u.rr_mx)) + l); 283 if ((*rr)->rr_u.rr_mx == NULL) 284 { 285 dns_free_data(r); 286 return NULL; 287 } 288 (*rr)->rr_u.rr_mx->mx_r_preference = (p[0] << 8) | p[1]; 289 (void) sm_strlcpy((*rr)->rr_u.rr_mx->mx_r_domain, 290 host, l); 291 break; 292 293 case T_SRV: 294 status = dn_expand(data, data + len, p + 6, host, 295 sizeof(host)); 296 if (status < 0) 297 { 298 dns_free_data(r); 299 return NULL; 300 } 301 l = strlen(host) + 1; 302 (*rr)->rr_u.rr_srv = (SRV_RECORDT_T*) 303 sm_malloc(sizeof(*((*rr)->rr_u.rr_srv)) + l); 304 if ((*rr)->rr_u.rr_srv == NULL) 305 { 306 dns_free_data(r); 307 return NULL; 308 } 309 (*rr)->rr_u.rr_srv->srv_r_priority = (p[0] << 8) | p[1]; 310 (*rr)->rr_u.rr_srv->srv_r_weight = (p[2] << 8) | p[3]; 311 (*rr)->rr_u.rr_srv->srv_r_port = (p[4] << 8) | p[5]; 312 (void) sm_strlcpy((*rr)->rr_u.rr_srv->srv_r_target, 313 host, l); 314 break; 315 316 case T_TXT: 317 318 /* 319 ** The TXT record contains the length as 320 ** leading byte, hence the value is restricted 321 ** to 255, which is less than the maximum value 322 ** of RDLENGTH (size). Nevertheless, txtlen 323 ** must be less than size because the latter 324 ** specifies the length of the entire TXT 325 ** record. 326 */ 327 328 txtlen = *p; 329 if (txtlen >= size) 330 { 331 if (LogLevel > 5) 332 sm_syslog(LOG_WARNING, NOQID, 333 "ERROR: DNS TXT record size=%d <= text len=%d", 334 size, txtlen); 335 dns_free_data(r); 336 return NULL; 337 } 338 (*rr)->rr_u.rr_txt = (char *) sm_malloc(txtlen + 1); 339 if ((*rr)->rr_u.rr_txt == NULL) 340 { 341 dns_free_data(r); 342 return NULL; 343 } 344 (void) sm_strlcpy((*rr)->rr_u.rr_txt, (char*) p + 1, 345 txtlen + 1); 346 break; 347 348 default: 349 (*rr)->rr_u.rr_data = (unsigned char*) sm_malloc(size); 350 if ((*rr)->rr_u.rr_data == NULL) 351 { 352 dns_free_data(r); 353 return NULL; 354 } 355 (void) memcpy((*rr)->rr_u.rr_data, p, size); 356 break; 357 } 358 p += size; 359 rr = &(*rr)->rr_next; 360 } 361 *rr = NULL; 362 return r; 363 } 364 365 /* 366 ** DNS_LOOKUP_INT -- perform dns map lookup (internal helper routine) 367 ** 368 ** Parameters: 369 ** domain -- name to lookup 370 ** rr_class -- resource record class 371 ** rr_type -- resource record type 372 ** retrans -- retransmission timeout 373 ** retry -- number of retries 374 ** 375 ** Returns: 376 ** result of lookup if succeeded. 377 ** NULL otherwise. 378 */ 379 380 DNS_REPLY_T * 381 dns_lookup_int(domain, rr_class, rr_type, retrans, retry) 382 const char *domain; 383 int rr_class; 384 int rr_type; 385 time_t retrans; 386 int retry; 387 { 388 int len; 389 unsigned long old_options = 0; 390 time_t save_retrans = 0; 391 int save_retry = 0; 392 DNS_REPLY_T *r = NULL; 393 unsigned char reply[1024]; 394 395 if (tTd(8, 16)) 396 { 397 old_options = _res.options; 398 _res.options |= RES_DEBUG; 399 sm_dprintf("dns_lookup(%s, %d, %s)\n", domain, 400 rr_class, dns_type_to_string(rr_type)); 401 } 402 if (retrans > 0) 403 { 404 save_retrans = _res.retrans; 405 _res.retrans = retrans; 406 } 407 if (retry > 0) 408 { 409 save_retry = _res.retry; 410 _res.retry = retry; 411 } 412 errno = 0; 413 SM_SET_H_ERRNO(0); 414 len = res_search(domain, rr_class, rr_type, reply, sizeof(reply)); 415 if (tTd(8, 16)) 416 { 417 _res.options = old_options; 418 sm_dprintf("dns_lookup(%s, %d, %s) --> %d\n", 419 domain, rr_class, dns_type_to_string(rr_type), len); 420 } 421 if (len >= 0) 422 r = parse_dns_reply(reply, len); 423 if (retrans > 0) 424 _res.retrans = save_retrans; 425 if (retry > 0) 426 _res.retry = save_retry; 427 return r; 428 } 429 430 # if 0 431 DNS_REPLY_T * 432 dns_lookup(domain, type_name, retrans, retry) 433 const char *domain; 434 const char *type_name; 435 time_t retrans; 436 int retry; 437 { 438 int type; 439 440 type = dns_string_to_type(type_name); 441 if (type == -1) 442 { 443 if (tTd(8, 16)) 444 sm_dprintf("dns_lookup: unknown resource type: `%s'\n", 445 type_name); 446 return NULL; 447 } 448 return dns_lookup_int(domain, C_IN, type, retrans, retry); 449 } 450 # endif /* 0 */ 451 # endif /* NAMED_BIND */ 452 #endif /* DNSMAP */ 453