1 /* 2 * tsig.c 3 * 4 * contains the functions needed for TSIG [RFC2845] 5 * 6 * (c) 2005-2006 NLnet Labs 7 * See the file LICENSE for the license 8 */ 9 10 #include <ldns/config.h> 11 12 #include <ldns/ldns.h> 13 14 #include <strings.h> 15 16 #ifdef HAVE_SSL 17 #include <openssl/hmac.h> 18 #include <openssl/md5.h> 19 #endif /* HAVE_SSL */ 20 21 char * 22 ldns_tsig_algorithm(ldns_tsig_credentials *tc) 23 { 24 return tc->algorithm; 25 } 26 27 char * 28 ldns_tsig_keyname(ldns_tsig_credentials *tc) 29 { 30 return tc->keyname; 31 } 32 33 char * 34 ldns_tsig_keydata(ldns_tsig_credentials *tc) 35 { 36 return tc->keydata; 37 } 38 39 char * 40 ldns_tsig_keyname_clone(ldns_tsig_credentials *tc) 41 { 42 return strdup(tc->keyname); 43 } 44 45 char * 46 ldns_tsig_keydata_clone(ldns_tsig_credentials *tc) 47 { 48 return strdup(tc->keydata); 49 } 50 51 /* 52 * Makes an exact copy of the wire, but with the tsig rr removed 53 */ 54 uint8_t * 55 ldns_tsig_prepare_pkt_wire(uint8_t *wire, size_t wire_len, size_t *result_len) 56 { 57 uint8_t *wire2 = NULL; 58 uint16_t qd_count; 59 uint16_t an_count; 60 uint16_t ns_count; 61 uint16_t ar_count; 62 ldns_rr *rr; 63 64 size_t pos; 65 uint16_t i; 66 67 ldns_status status; 68 69 if(wire_len < LDNS_HEADER_SIZE) { 70 return NULL; 71 } 72 /* fake parse the wire */ 73 qd_count = LDNS_QDCOUNT(wire); 74 an_count = LDNS_ANCOUNT(wire); 75 ns_count = LDNS_NSCOUNT(wire); 76 ar_count = LDNS_ARCOUNT(wire); 77 78 if (ar_count > 0) { 79 ar_count--; 80 } else { 81 return NULL; 82 } 83 84 pos = LDNS_HEADER_SIZE; 85 86 for (i = 0; i < qd_count; i++) { 87 status = ldns_wire2rr(&rr, wire, wire_len, &pos, LDNS_SECTION_QUESTION); 88 if (status != LDNS_STATUS_OK) { 89 return NULL; 90 } 91 ldns_rr_free(rr); 92 } 93 94 for (i = 0; i < an_count; i++) { 95 status = ldns_wire2rr(&rr, wire, wire_len, &pos, LDNS_SECTION_ANSWER); 96 if (status != LDNS_STATUS_OK) { 97 return NULL; 98 } 99 ldns_rr_free(rr); 100 } 101 102 for (i = 0; i < ns_count; i++) { 103 status = ldns_wire2rr(&rr, wire, wire_len, &pos, LDNS_SECTION_AUTHORITY); 104 if (status != LDNS_STATUS_OK) { 105 return NULL; 106 } 107 ldns_rr_free(rr); 108 } 109 110 for (i = 0; i < ar_count; i++) { 111 status = ldns_wire2rr(&rr, wire, wire_len, &pos, 112 LDNS_SECTION_ADDITIONAL); 113 if (status != LDNS_STATUS_OK) { 114 return NULL; 115 } 116 ldns_rr_free(rr); 117 } 118 119 *result_len = pos; 120 wire2 = LDNS_XMALLOC(uint8_t, *result_len); 121 if(!wire2) { 122 return NULL; 123 } 124 memcpy(wire2, wire, *result_len); 125 126 ldns_write_uint16(wire2 + LDNS_ARCOUNT_OFF, ar_count); 127 128 return wire2; 129 } 130 131 #ifdef HAVE_SSL 132 static const EVP_MD * 133 ldns_digest_function(char *name) 134 { 135 /* these are the mandatory algorithms from RFC4635 */ 136 /* The optional algorithms are not yet implemented */ 137 if (strlen(name) == 12 && strncasecmp(name, "hmac-sha256.", 11) == 0) { 138 #ifdef HAVE_EVP_SHA256 139 return EVP_sha256(); 140 #else 141 return NULL; 142 #endif 143 } else if (strlen(name) == 10 && strncasecmp(name, "hmac-sha1.", 9) == 0) 144 return EVP_sha1(); 145 else if (strlen(name) == 25 && strncasecmp(name, 146 "hmac-md5.sig-alg.reg.int.", 25) == 0) 147 return EVP_md5(); 148 else 149 return NULL; 150 } 151 #endif 152 153 #ifdef HAVE_SSL 154 static ldns_status 155 ldns_tsig_mac_new(ldns_rdf **tsig_mac, uint8_t *pkt_wire, size_t pkt_wire_size, 156 const char *key_data, ldns_rdf *key_name_rdf, ldns_rdf *fudge_rdf, 157 ldns_rdf *algorithm_rdf, ldns_rdf *time_signed_rdf, ldns_rdf *error_rdf, 158 ldns_rdf *other_data_rdf, ldns_rdf *orig_mac_rdf, int tsig_timers_only) 159 { 160 char *wireformat; 161 int wiresize; 162 unsigned char *mac_bytes; 163 unsigned char *key_bytes; 164 int key_size; 165 const EVP_MD *digester; 166 char *algorithm_name; 167 unsigned int md_len = EVP_MAX_MD_SIZE; 168 ldns_rdf *result = NULL; 169 ldns_buffer *data_buffer = NULL; 170 171 /* 172 * prepare the digestable information 173 */ 174 data_buffer = ldns_buffer_new(LDNS_MAX_PACKETLEN); 175 if(!data_buffer) { 176 return LDNS_STATUS_MEM_ERR; 177 } 178 /* if orig_mac is not NULL, add it too */ 179 if (orig_mac_rdf) { 180 (void) ldns_rdf2buffer_wire(data_buffer, orig_mac_rdf); 181 } 182 ldns_buffer_write(data_buffer, pkt_wire, pkt_wire_size); 183 if (!tsig_timers_only) { 184 (void)ldns_rdf2buffer_wire(data_buffer, key_name_rdf); 185 ldns_buffer_write_u16(data_buffer, LDNS_RR_CLASS_ANY); 186 ldns_buffer_write_u32(data_buffer, 0); 187 (void)ldns_rdf2buffer_wire(data_buffer, algorithm_rdf); 188 } 189 (void)ldns_rdf2buffer_wire(data_buffer, time_signed_rdf); 190 (void)ldns_rdf2buffer_wire(data_buffer, fudge_rdf); 191 if (!tsig_timers_only) { 192 (void)ldns_rdf2buffer_wire(data_buffer, error_rdf); 193 (void)ldns_rdf2buffer_wire(data_buffer, other_data_rdf); 194 } 195 196 wireformat = (char *) data_buffer->_data; 197 wiresize = (int) ldns_buffer_position(data_buffer); 198 199 algorithm_name = ldns_rdf2str(algorithm_rdf); 200 if(!algorithm_name) { 201 ldns_buffer_free(data_buffer); 202 return LDNS_STATUS_MEM_ERR; 203 } 204 205 /* prepare the key */ 206 key_bytes = LDNS_XMALLOC(unsigned char, 207 ldns_b64_pton_calculate_size(strlen(key_data))); 208 if(!key_bytes) { 209 LDNS_FREE(algorithm_name); 210 ldns_buffer_free(data_buffer); 211 return LDNS_STATUS_MEM_ERR; 212 } 213 key_size = ldns_b64_pton(key_data, key_bytes, 214 ldns_b64_pton_calculate_size(strlen(key_data))); 215 if (key_size < 0) { 216 LDNS_FREE(algorithm_name); 217 LDNS_FREE(key_bytes); 218 ldns_buffer_free(data_buffer); 219 /* LDNS_STATUS_INVALID_B64 */ 220 return LDNS_STATUS_INVALID_B64; 221 } 222 /* hmac it */ 223 /* 2 spare bytes for the length */ 224 mac_bytes = LDNS_XMALLOC(unsigned char, md_len+2); 225 if(!mac_bytes) { 226 LDNS_FREE(algorithm_name); 227 LDNS_FREE(key_bytes); 228 ldns_buffer_free(data_buffer); 229 return LDNS_STATUS_MEM_ERR; 230 } 231 memset(mac_bytes, 0, md_len+2); 232 233 digester = ldns_digest_function(algorithm_name); 234 235 if (digester) { 236 (void) HMAC(digester, key_bytes, key_size, (void *)wireformat, 237 (size_t) wiresize, mac_bytes + 2, &md_len); 238 239 ldns_write_uint16(mac_bytes, md_len); 240 result = ldns_rdf_new_frm_data(LDNS_RDF_TYPE_INT16_DATA, md_len + 2, 241 mac_bytes); 242 } else { 243 LDNS_FREE(algorithm_name); 244 LDNS_FREE(mac_bytes); 245 LDNS_FREE(key_bytes); 246 ldns_buffer_free(data_buffer); 247 return LDNS_STATUS_CRYPTO_UNKNOWN_ALGO; 248 } 249 250 LDNS_FREE(algorithm_name); 251 LDNS_FREE(mac_bytes); 252 LDNS_FREE(key_bytes); 253 ldns_buffer_free(data_buffer); 254 255 *tsig_mac = result; 256 257 return LDNS_STATUS_OK; 258 } 259 #endif /* HAVE_SSL */ 260 261 262 #ifdef HAVE_SSL 263 bool 264 ldns_pkt_tsig_verify(ldns_pkt *pkt, uint8_t *wire, size_t wirelen, const char *key_name, 265 const char *key_data, ldns_rdf *orig_mac_rdf) 266 { 267 return ldns_pkt_tsig_verify_next(pkt, wire, wirelen, key_name, key_data, orig_mac_rdf, 0); 268 } 269 270 bool 271 ldns_pkt_tsig_verify_next(ldns_pkt *pkt, uint8_t *wire, size_t wirelen, const char* key_name, 272 const char *key_data, ldns_rdf *orig_mac_rdf, int tsig_timers_only) 273 { 274 ldns_rdf *fudge_rdf; 275 ldns_rdf *algorithm_rdf; 276 ldns_rdf *time_signed_rdf; 277 ldns_rdf *orig_id_rdf; 278 ldns_rdf *error_rdf; 279 ldns_rdf *other_data_rdf; 280 ldns_rdf *pkt_mac_rdf; 281 ldns_rdf *my_mac_rdf; 282 ldns_rdf *key_name_rdf = ldns_rdf_new_frm_str(LDNS_RDF_TYPE_DNAME, key_name); 283 uint16_t pkt_id, orig_pkt_id; 284 ldns_status status; 285 286 uint8_t *prepared_wire = NULL; 287 size_t prepared_wire_size = 0; 288 289 ldns_rr *orig_tsig = ldns_pkt_tsig(pkt); 290 291 if (!orig_tsig) { 292 ldns_rdf_deep_free(key_name_rdf); 293 return false; 294 } 295 algorithm_rdf = ldns_rr_rdf(orig_tsig, 0); 296 time_signed_rdf = ldns_rr_rdf(orig_tsig, 1); 297 fudge_rdf = ldns_rr_rdf(orig_tsig, 2); 298 pkt_mac_rdf = ldns_rr_rdf(orig_tsig, 3); 299 orig_id_rdf = ldns_rr_rdf(orig_tsig, 4); 300 error_rdf = ldns_rr_rdf(orig_tsig, 5); 301 other_data_rdf = ldns_rr_rdf(orig_tsig, 6); 302 303 /* remove temporarily */ 304 ldns_pkt_set_tsig(pkt, NULL); 305 /* temporarily change the id to the original id */ 306 pkt_id = ldns_pkt_id(pkt); 307 orig_pkt_id = ldns_rdf2native_int16(orig_id_rdf); 308 ldns_pkt_set_id(pkt, orig_pkt_id); 309 310 prepared_wire = ldns_tsig_prepare_pkt_wire(wire, wirelen, &prepared_wire_size); 311 312 status = ldns_tsig_mac_new(&my_mac_rdf, prepared_wire, prepared_wire_size, 313 key_data, key_name_rdf, fudge_rdf, algorithm_rdf, 314 time_signed_rdf, error_rdf, other_data_rdf, orig_mac_rdf, tsig_timers_only); 315 316 LDNS_FREE(prepared_wire); 317 318 if (status != LDNS_STATUS_OK) { 319 ldns_rdf_deep_free(key_name_rdf); 320 return false; 321 } 322 /* Put back the values */ 323 ldns_pkt_set_tsig(pkt, orig_tsig); 324 ldns_pkt_set_id(pkt, pkt_id); 325 326 ldns_rdf_deep_free(key_name_rdf); 327 328 if (ldns_rdf_compare(pkt_mac_rdf, my_mac_rdf) == 0) { 329 ldns_rdf_deep_free(my_mac_rdf); 330 return true; 331 } else { 332 ldns_rdf_deep_free(my_mac_rdf); 333 return false; 334 } 335 } 336 #endif /* HAVE_SSL */ 337 338 #ifdef HAVE_SSL 339 ldns_status 340 ldns_pkt_tsig_sign(ldns_pkt *pkt, const char *key_name, const char *key_data, 341 uint16_t fudge, const char *algorithm_name, ldns_rdf *query_mac) 342 { 343 return ldns_pkt_tsig_sign_next(pkt, key_name, key_data, fudge, algorithm_name, query_mac, 0); 344 } 345 346 ldns_status 347 ldns_pkt_tsig_sign_next(ldns_pkt *pkt, const char *key_name, const char *key_data, 348 uint16_t fudge, const char *algorithm_name, ldns_rdf *query_mac, int tsig_timers_only) 349 { 350 ldns_rr *tsig_rr; 351 ldns_rdf *key_name_rdf = ldns_rdf_new_frm_str(LDNS_RDF_TYPE_DNAME, key_name); 352 ldns_rdf *fudge_rdf = NULL; 353 ldns_rdf *orig_id_rdf = NULL; 354 ldns_rdf *algorithm_rdf; 355 ldns_rdf *error_rdf = NULL; 356 ldns_rdf *mac_rdf = NULL; 357 ldns_rdf *other_data_rdf = NULL; 358 359 ldns_status status = LDNS_STATUS_OK; 360 361 uint8_t *pkt_wire = NULL; 362 size_t pkt_wire_len; 363 364 struct timeval tv_time_signed; 365 uint8_t *time_signed = NULL; 366 ldns_rdf *time_signed_rdf = NULL; 367 368 algorithm_rdf = ldns_rdf_new_frm_str(LDNS_RDF_TYPE_DNAME, algorithm_name); 369 if(!key_name_rdf || !algorithm_rdf) { 370 status = LDNS_STATUS_MEM_ERR; 371 goto clean; 372 } 373 374 /* eww don't have create tsigtime rdf yet :( */ 375 /* bleh :p */ 376 if (gettimeofday(&tv_time_signed, NULL) == 0) { 377 time_signed = LDNS_XMALLOC(uint8_t, 6); 378 if(!time_signed) { 379 status = LDNS_STATUS_MEM_ERR; 380 goto clean; 381 } 382 ldns_write_uint64_as_uint48(time_signed, 383 (uint64_t)tv_time_signed.tv_sec); 384 } else { 385 status = LDNS_STATUS_INTERNAL_ERR; 386 goto clean; 387 } 388 389 time_signed_rdf = ldns_rdf_new(LDNS_RDF_TYPE_TSIGTIME, 6, time_signed); 390 if(!time_signed_rdf) { 391 LDNS_FREE(time_signed); 392 status = LDNS_STATUS_MEM_ERR; 393 goto clean; 394 } 395 396 fudge_rdf = ldns_native2rdf_int16(LDNS_RDF_TYPE_INT16, fudge); 397 398 orig_id_rdf = ldns_native2rdf_int16(LDNS_RDF_TYPE_INT16, ldns_pkt_id(pkt)); 399 400 error_rdf = ldns_native2rdf_int16(LDNS_RDF_TYPE_INT16, 0); 401 402 other_data_rdf = ldns_native2rdf_int16_data(0, NULL); 403 404 if(!fudge_rdf || !orig_id_rdf || !error_rdf || !other_data_rdf) { 405 status = LDNS_STATUS_MEM_ERR; 406 goto clean; 407 } 408 409 if (ldns_pkt2wire(&pkt_wire, pkt, &pkt_wire_len) != LDNS_STATUS_OK) { 410 status = LDNS_STATUS_ERR; 411 goto clean; 412 } 413 414 status = ldns_tsig_mac_new(&mac_rdf, pkt_wire, pkt_wire_len, 415 key_data, key_name_rdf, fudge_rdf, algorithm_rdf, 416 time_signed_rdf, error_rdf, other_data_rdf, query_mac, tsig_timers_only); 417 418 if (!mac_rdf) { 419 goto clean; 420 } 421 422 LDNS_FREE(pkt_wire); 423 424 /* Create the TSIG RR */ 425 tsig_rr = ldns_rr_new(); 426 if(!tsig_rr) { 427 status = LDNS_STATUS_MEM_ERR; 428 goto clean; 429 } 430 ldns_rr_set_owner(tsig_rr, key_name_rdf); 431 ldns_rr_set_class(tsig_rr, LDNS_RR_CLASS_ANY); 432 ldns_rr_set_type(tsig_rr, LDNS_RR_TYPE_TSIG); 433 ldns_rr_set_ttl(tsig_rr, 0); 434 435 ldns_rr_push_rdf(tsig_rr, algorithm_rdf); 436 ldns_rr_push_rdf(tsig_rr, time_signed_rdf); 437 ldns_rr_push_rdf(tsig_rr, fudge_rdf); 438 ldns_rr_push_rdf(tsig_rr, mac_rdf); 439 ldns_rr_push_rdf(tsig_rr, orig_id_rdf); 440 ldns_rr_push_rdf(tsig_rr, error_rdf); 441 ldns_rr_push_rdf(tsig_rr, other_data_rdf); 442 443 ldns_pkt_set_tsig(pkt, tsig_rr); 444 445 return status; 446 447 clean: 448 LDNS_FREE(pkt_wire); 449 ldns_rdf_free(key_name_rdf); 450 ldns_rdf_free(algorithm_rdf); 451 ldns_rdf_free(time_signed_rdf); 452 ldns_rdf_free(fudge_rdf); 453 ldns_rdf_free(orig_id_rdf); 454 ldns_rdf_free(error_rdf); 455 ldns_rdf_free(other_data_rdf); 456 return status; 457 } 458 #endif /* HAVE_SSL */ 459