1 /* 2 * dnssec.c 3 * Some DNSSEC helper function are defined here 4 * and tracing is done 5 * (c) 2005 NLnet Labs 6 * 7 * See the file LICENSE for the license 8 * 9 */ 10 11 #include "drill.h" 12 #include <ldns/ldns.h> 13 14 /* get rr_type from a server from a server */ 15 ldns_rr_list * 16 get_rr(ldns_resolver *res, ldns_rdf *zname, ldns_rr_type t, ldns_rr_class c) 17 { 18 /* query, retrieve, extract and return */ 19 ldns_pkt *p; 20 ldns_rr_list *found; 21 22 p = ldns_pkt_new(); 23 found = NULL; 24 25 if (ldns_resolver_send(&p, res, zname, t, c, 0) != LDNS_STATUS_OK) { 26 /* oops */ 27 return NULL; 28 } else { 29 found = ldns_pkt_rr_list_by_type(p, t, LDNS_SECTION_ANY_NOQUESTION); 30 } 31 return found; 32 } 33 34 void 35 drill_pkt_print(FILE *fd, ldns_resolver *r, ldns_pkt *p) 36 { 37 ldns_rr_list *new_nss; 38 ldns_rr_list *hostnames; 39 40 if (verbosity < 5) { 41 return; 42 } 43 44 hostnames = ldns_get_rr_list_name_by_addr(r, ldns_pkt_answerfrom(p), 0, 0); 45 46 new_nss = ldns_pkt_rr_list_by_type(p, 47 LDNS_RR_TYPE_NS, LDNS_SECTION_ANSWER); 48 ldns_rr_list_print(fd, new_nss); 49 50 /* new_nss can be empty.... */ 51 52 fprintf(fd, ";; Received %d bytes from %s#%d(", 53 (int) ldns_pkt_size(p), 54 ldns_rdf2str(ldns_pkt_answerfrom(p)), 55 (int) ldns_resolver_port(r)); 56 /* if we can resolve this print it, other print the ip again */ 57 if (hostnames) { 58 ldns_rdf_print(fd, 59 ldns_rr_rdf(ldns_rr_list_rr(hostnames, 0), 0)); 60 ldns_rr_list_deep_free(hostnames); 61 } else { 62 fprintf(fd, "%s", ldns_rdf2str(ldns_pkt_answerfrom(p))); 63 } 64 fprintf(fd, ") in %u ms\n\n", (unsigned int)ldns_pkt_querytime(p)); 65 } 66 67 void 68 drill_pkt_print_footer(FILE *fd, ldns_resolver *r, ldns_pkt *p) 69 { 70 ldns_rr_list *hostnames; 71 72 if (verbosity < 5) { 73 return; 74 } 75 76 hostnames = ldns_get_rr_list_name_by_addr(r, ldns_pkt_answerfrom(p), 0, 0); 77 78 fprintf(fd, ";; Received %d bytes from %s#%d(", 79 (int) ldns_pkt_size(p), 80 ldns_rdf2str(ldns_pkt_answerfrom(p)), 81 (int) ldns_resolver_port(r)); 82 /* if we can resolve this print it, other print the ip again */ 83 if (hostnames) { 84 ldns_rdf_print(fd, 85 ldns_rr_rdf(ldns_rr_list_rr(hostnames, 0), 0)); 86 ldns_rr_list_deep_free(hostnames); 87 } else { 88 fprintf(fd, "%s", ldns_rdf2str(ldns_pkt_answerfrom(p))); 89 } 90 fprintf(fd, ") in %u ms\n\n", (unsigned int)ldns_pkt_querytime(p)); 91 } 92 /* 93 * generic function to get some RRset from a nameserver 94 * and possible some signatures too (that would be the day...) 95 */ 96 ldns_pkt_type 97 get_dnssec_rr(ldns_pkt *p, ldns_rdf *name, ldns_rr_type t, 98 ldns_rr_list **rrlist, ldns_rr_list **sig) 99 { 100 ldns_pkt_type pt = LDNS_PACKET_UNKNOWN; 101 ldns_rr_list *rr = NULL; 102 ldns_rr_list *sigs = NULL; 103 size_t i; 104 105 if (!p) { 106 if (rrlist) { 107 *rrlist = NULL; 108 } 109 return LDNS_PACKET_UNKNOWN; 110 } 111 112 pt = ldns_pkt_reply_type(p); 113 if (name) { 114 rr = ldns_pkt_rr_list_by_name_and_type(p, name, t, LDNS_SECTION_ANSWER); 115 if (!rr) { 116 rr = ldns_pkt_rr_list_by_name_and_type(p, name, t, LDNS_SECTION_AUTHORITY); 117 } 118 sigs = ldns_pkt_rr_list_by_name_and_type(p, name, LDNS_RR_TYPE_RRSIG, 119 LDNS_SECTION_ANSWER); 120 if (!sigs) { 121 sigs = ldns_pkt_rr_list_by_name_and_type(p, name, LDNS_RR_TYPE_RRSIG, 122 LDNS_SECTION_AUTHORITY); 123 } 124 } else { 125 /* A DS-referral - get the DS records if they are there */ 126 rr = ldns_pkt_rr_list_by_type(p, t, LDNS_SECTION_AUTHORITY); 127 sigs = ldns_pkt_rr_list_by_type(p, LDNS_RR_TYPE_RRSIG, 128 LDNS_SECTION_AUTHORITY); 129 } 130 if (sig) { 131 *sig = ldns_rr_list_new(); 132 for (i = 0; i < ldns_rr_list_rr_count(sigs); i++) { 133 /* only add the sigs that cover this type */ 134 if (ldns_rdf2rr_type(ldns_rr_rrsig_typecovered(ldns_rr_list_rr(sigs, i))) == 135 t) { 136 ldns_rr_list_push_rr(*sig, ldns_rr_clone(ldns_rr_list_rr(sigs, i))); 137 } 138 } 139 } 140 ldns_rr_list_deep_free(sigs); 141 if (rrlist) { 142 *rrlist = rr; 143 } 144 145 if (pt == LDNS_PACKET_NXDOMAIN || pt == LDNS_PACKET_NODATA) { 146 return pt; 147 } else { 148 return LDNS_PACKET_ANSWER; 149 } 150 } 151 152 153 ldns_status 154 ldns_verify_denial(ldns_pkt *pkt, ldns_rdf *name, ldns_rr_type type, ldns_rr_list **nsec_rrs, ldns_rr_list **nsec_rr_sigs) 155 { 156 uint16_t nsec_i; 157 158 ldns_rr_list *nsecs; 159 ldns_status result; 160 161 if (verbosity >= 5) { 162 printf("VERIFY DENIAL FROM:\n"); 163 ldns_pkt_print(stdout, pkt); 164 } 165 166 result = LDNS_STATUS_CRYPTO_NO_RRSIG; 167 /* Try to see if there are NSECS in the packet */ 168 nsecs = ldns_pkt_rr_list_by_type(pkt, LDNS_RR_TYPE_NSEC, LDNS_SECTION_ANY_NOQUESTION); 169 if (nsecs) { 170 for (nsec_i = 0; nsec_i < ldns_rr_list_rr_count(nsecs); nsec_i++) { 171 /* there are four options: 172 * - name equals ownername and is covered by the type bitmap 173 * - name equals ownername but is not covered by the type bitmap 174 * - name falls within nsec coverage but is not equal to the owner name 175 * - name falls outside of nsec coverage 176 */ 177 if (ldns_dname_compare(ldns_rr_owner(ldns_rr_list_rr(nsecs, nsec_i)), name) == 0) { 178 /* 179 printf("CHECKING NSEC:\n"); 180 ldns_rr_print(stdout, ldns_rr_list_rr(nsecs, nsec_i)); 181 printf("DAWASEM\n"); 182 */ 183 if (ldns_nsec_bitmap_covers_type( 184 ldns_nsec_get_bitmap(ldns_rr_list_rr(nsecs, 185 nsec_i)), 186 type)) { 187 /* Error, according to the nsec this rrset is signed */ 188 result = LDNS_STATUS_CRYPTO_NO_RRSIG; 189 } else { 190 /* ok nsec denies existence */ 191 if (verbosity >= 3) { 192 printf(";; Existence of data set with this type denied by NSEC\n"); 193 } 194 /*printf(";; Verifiably insecure.\n");*/ 195 if (nsec_rrs && nsec_rr_sigs) { 196 (void) get_dnssec_rr(pkt, ldns_rr_owner(ldns_rr_list_rr(nsecs, nsec_i)), LDNS_RR_TYPE_NSEC, nsec_rrs, nsec_rr_sigs); 197 } 198 ldns_rr_list_deep_free(nsecs); 199 return LDNS_STATUS_OK; 200 } 201 } else if (ldns_nsec_covers_name(ldns_rr_list_rr(nsecs, nsec_i), name)) { 202 if (verbosity >= 3) { 203 printf(";; Existence of data set with this name denied by NSEC\n"); 204 } 205 if (nsec_rrs && nsec_rr_sigs) { 206 (void) get_dnssec_rr(pkt, ldns_rr_owner(ldns_rr_list_rr(nsecs, nsec_i)), LDNS_RR_TYPE_NSEC, nsec_rrs, nsec_rr_sigs); 207 } 208 ldns_rr_list_deep_free(nsecs); 209 return LDNS_STATUS_OK; 210 } else { 211 /* nsec has nothing to do with this data */ 212 } 213 } 214 ldns_rr_list_deep_free(nsecs); 215 } 216 return result; 217 } 218 219 /* NSEC3 draft -07 */ 220 /*return hash name match*/ 221 ldns_rr * 222 ldns_nsec3_exact_match(ldns_rdf *qname, ldns_rr_type qtype, ldns_rr_list *nsec3s) { 223 uint8_t algorithm; 224 uint32_t iterations; 225 uint8_t salt_length; 226 uint8_t *salt; 227 228 ldns_rdf *sname, *hashed_sname; 229 230 size_t nsec_i; 231 ldns_rr *nsec; 232 ldns_rr *result = NULL; 233 234 ldns_status status; 235 236 const ldns_rr_descriptor *descriptor; 237 238 ldns_rdf *zone_name; 239 240 if (verbosity >= 4) { 241 printf(";; finding exact match for "); 242 descriptor = ldns_rr_descript(qtype); 243 if (descriptor && descriptor->_name) { 244 printf("%s ", descriptor->_name); 245 } else { 246 printf("TYPE%d ", qtype); 247 } 248 ldns_rdf_print(stdout, qname); 249 printf("\n"); 250 } 251 252 if (!qname || !nsec3s || ldns_rr_list_rr_count(nsec3s) < 1) { 253 if (verbosity >= 4) { 254 printf("no qname, nsec3s or list empty\n"); 255 } 256 return NULL; 257 } 258 259 nsec = ldns_rr_list_rr(nsec3s, 0); 260 algorithm = ldns_nsec3_algorithm(nsec); 261 salt_length = ldns_nsec3_salt_length(nsec); 262 salt = ldns_nsec3_salt_data(nsec); 263 iterations = ldns_nsec3_iterations(nsec); 264 265 sname = ldns_rdf_clone(qname); 266 267 if (verbosity >= 4) { 268 printf(";; owner name hashes to: "); 269 } 270 hashed_sname = ldns_nsec3_hash_name(sname, algorithm, iterations, salt_length, salt); 271 272 zone_name = ldns_dname_left_chop(ldns_rr_owner(nsec)); 273 status = ldns_dname_cat(hashed_sname, zone_name); 274 275 if (verbosity >= 4) { 276 ldns_rdf_print(stdout, hashed_sname); 277 printf("\n"); 278 } 279 280 for (nsec_i = 0; nsec_i < ldns_rr_list_rr_count(nsec3s); nsec_i++) { 281 nsec = ldns_rr_list_rr(nsec3s, nsec_i); 282 283 /* check values of iterations etc! */ 284 285 /* exact match? */ 286 if (ldns_dname_compare(ldns_rr_owner(nsec), hashed_sname) == 0) { 287 result = nsec; 288 goto done; 289 } 290 291 } 292 293 done: 294 ldns_rdf_deep_free(zone_name); 295 ldns_rdf_deep_free(sname); 296 ldns_rdf_deep_free(hashed_sname); 297 LDNS_FREE(salt); 298 299 if (verbosity >= 4) { 300 if (result) { 301 printf(";; Found.\n"); 302 } else { 303 printf(";; Not foud.\n"); 304 } 305 } 306 return result; 307 } 308 309 /*return the owner name of the closest encloser for name from the list of rrs */ 310 /* this is NOT the hash, but the original name! */ 311 ldns_rdf * 312 ldns_nsec3_closest_encloser(ldns_rdf *qname, ldns_rr_type qtype, ldns_rr_list *nsec3s) 313 { 314 /* remember parameters, they must match */ 315 uint8_t algorithm; 316 uint32_t iterations; 317 uint8_t salt_length; 318 uint8_t *salt; 319 320 ldns_rdf *sname, *hashed_sname, *tmp; 321 ldns_rr *ce; 322 bool flag; 323 324 bool exact_match_found; 325 bool in_range_found; 326 327 ldns_status status; 328 ldns_rdf *zone_name; 329 330 size_t nsec_i; 331 ldns_rr *nsec; 332 ldns_rdf *result = NULL; 333 334 if (!qname || !nsec3s || ldns_rr_list_rr_count(nsec3s) < 1) { 335 return NULL; 336 } 337 338 if (verbosity >= 4) { 339 printf(";; finding closest encloser for type %d ", qtype); 340 ldns_rdf_print(stdout, qname); 341 printf("\n"); 342 } 343 344 nsec = ldns_rr_list_rr(nsec3s, 0); 345 algorithm = ldns_nsec3_algorithm(nsec); 346 salt_length = ldns_nsec3_salt_length(nsec); 347 salt = ldns_nsec3_salt_data(nsec); 348 iterations = ldns_nsec3_iterations(nsec); 349 350 sname = ldns_rdf_clone(qname); 351 352 ce = NULL; 353 flag = false; 354 355 zone_name = ldns_dname_left_chop(ldns_rr_owner(nsec)); 356 357 /* algorithm from nsec3-07 8.3 */ 358 while (ldns_dname_label_count(sname) > 0) { 359 exact_match_found = false; 360 in_range_found = false; 361 362 if (verbosity >= 3) { 363 printf(";; "); 364 ldns_rdf_print(stdout, sname); 365 printf(" hashes to: "); 366 } 367 hashed_sname = ldns_nsec3_hash_name(sname, algorithm, iterations, salt_length, salt); 368 369 status = ldns_dname_cat(hashed_sname, zone_name); 370 371 if (verbosity >= 3) { 372 ldns_rdf_print(stdout, hashed_sname); 373 printf("\n"); 374 } 375 376 for (nsec_i = 0; nsec_i < ldns_rr_list_rr_count(nsec3s); nsec_i++) { 377 nsec = ldns_rr_list_rr(nsec3s, nsec_i); 378 379 /* check values of iterations etc! */ 380 381 /* exact match? */ 382 if (ldns_dname_compare(ldns_rr_owner(nsec), hashed_sname) == 0) { 383 if (verbosity >= 4) { 384 printf(";; exact match found\n"); 385 } 386 exact_match_found = true; 387 } else if (ldns_nsec_covers_name(nsec, hashed_sname)) { 388 if (verbosity >= 4) { 389 printf(";; in range of an nsec\n"); 390 } 391 in_range_found = true; 392 } 393 394 } 395 if (!exact_match_found && in_range_found) { 396 flag = true; 397 } else if (exact_match_found && flag) { 398 result = ldns_rdf_clone(sname); 399 } else if (exact_match_found && !flag) { 400 // error! 401 if (verbosity >= 4) { 402 printf(";; the closest encloser is the same name (ie. this is an exact match, ie there is no closest encloser)\n"); 403 } 404 ldns_rdf_deep_free(hashed_sname); 405 goto done; 406 } else { 407 flag = false; 408 } 409 410 ldns_rdf_deep_free(hashed_sname); 411 tmp = sname; 412 sname = ldns_dname_left_chop(sname); 413 ldns_rdf_deep_free(tmp); 414 } 415 416 done: 417 LDNS_FREE(salt); 418 ldns_rdf_deep_free(zone_name); 419 ldns_rdf_deep_free(sname); 420 421 if (!result) { 422 if (verbosity >= 4) { 423 printf(";; no closest encloser found\n"); 424 } 425 } 426 427 /* todo checks from end of 6.2. here or in caller? */ 428 return result; 429 } 430 431 432 /* special case were there was a wildcard expansion match, the exact match must be disproven */ 433 ldns_status 434 ldns_verify_denial_wildcard(ldns_pkt *pkt, ldns_rdf *name, ldns_rr_type type, ldns_rr_list **nsec_rrs, ldns_rr_list **nsec_rr_sigs) 435 { 436 ldns_rdf *nsec3_ce = NULL; 437 ldns_rr *nsec3_ex = NULL; 438 ldns_rdf *wildcard_name = NULL; 439 ldns_rdf *nsec3_wc_ce = NULL; 440 ldns_rr *nsec3_wc_ex = NULL; 441 ldns_rdf *chopped_dname = NULL; 442 ldns_rr_list *nsecs; 443 ldns_status result = LDNS_STATUS_ERR; 444 445 nsecs = ldns_pkt_rr_list_by_type(pkt, LDNS_RR_TYPE_NSEC3, LDNS_SECTION_ANY_NOQUESTION); 446 if (nsecs) { 447 wildcard_name = ldns_dname_new_frm_str("*"); 448 chopped_dname = ldns_dname_left_chop(name); 449 result = ldns_dname_cat(wildcard_name, chopped_dname); 450 ldns_rdf_deep_free(chopped_dname); 451 452 nsec3_ex = ldns_nsec3_exact_match(name, type, nsecs); 453 nsec3_ce = ldns_nsec3_closest_encloser(name, type, nsecs); 454 nsec3_wc_ce = ldns_nsec3_closest_encloser(wildcard_name, type, nsecs); 455 nsec3_wc_ex = ldns_nsec3_exact_match(wildcard_name, type, nsecs); 456 457 if (nsec3_ex) { 458 if (verbosity >= 3) { 459 printf(";; Error, exact match for for name found, but should not exist (draft -07 section 8.8)\n"); 460 } 461 result = LDNS_STATUS_NSEC3_ERR; 462 } else if (!nsec3_ce) { 463 if (verbosity >= 3) { 464 printf(";; Error, closest encloser for exact match missing in wildcard response (draft -07 section 8.8)\n"); 465 } 466 result = LDNS_STATUS_NSEC3_ERR; 467 /* 468 } else if (!nsec3_wc_ex) { 469 printf(";; Error, no wildcard nsec3 match: "); 470 ldns_rdf_print(stdout, wildcard_name); 471 printf(" (draft -07 section 8.8)\n"); 472 result = LDNS_STATUS_NSEC3_ERR; 473 */ 474 /* } else if (!nsec */ 475 } else { 476 if (verbosity >= 3) { 477 printf(";; wilcard expansion proven\n"); 478 } 479 result = LDNS_STATUS_OK; 480 } 481 } else { 482 if (verbosity >= 3) { 483 printf(";; Error: no NSEC or NSEC3 records in answer\n"); 484 } 485 result = LDNS_STATUS_CRYPTO_NO_RRSIG; 486 } 487 488 if (nsecs && nsec_rrs && nsec_rr_sigs) { 489 (void) get_dnssec_rr(pkt, ldns_rr_owner(ldns_rr_list_rr(nsecs, 0)), LDNS_RR_TYPE_NSEC3, nsec_rrs, nsec_rr_sigs); 490 } 491 return result; 492 } 493 494 495