1 /* 2 * DTLS implementation written by Nagendra Modadugu 3 * (nagendra (at) cs.stanford.edu) for the OpenSSL project 2005. 4 */ 5 /* ==================================================================== 6 * Copyright (c) 1999-2007 The OpenSSL Project. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in 17 * the documentation and/or other materials provided with the 18 * distribution. 19 * 20 * 3. All advertising materials mentioning features or use of this 21 * software must display the following acknowledgment: 22 * "This product includes software developed by the OpenSSL Project 23 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" 24 * 25 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 26 * endorse or promote products derived from this software without 27 * prior written permission. For written permission, please contact 28 * openssl-core (at) OpenSSL.org. 29 * 30 * 5. Products derived from this software may not be called "OpenSSL" 31 * nor may "OpenSSL" appear in their names without prior written 32 * permission of the OpenSSL Project. 33 * 34 * 6. Redistributions of any form whatsoever must retain the following 35 * acknowledgment: 36 * "This product includes software developed by the OpenSSL Project 37 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" 38 * 39 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 40 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 41 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 42 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 43 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 44 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 45 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 46 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 48 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 49 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 50 * OF THE POSSIBILITY OF SUCH DAMAGE. 51 * ==================================================================== 52 * 53 * This product includes cryptographic software written by Eric Young 54 * (eay (at) cryptsoft.com). This product includes software written by Tim 55 * Hudson (tjh (at) cryptsoft.com). 56 * 57 */ 58 /* Copyright (C) 1995-1998 Eric Young (eay (at) cryptsoft.com) 59 * All rights reserved. 60 * 61 * This package is an SSL implementation written 62 * by Eric Young (eay (at) cryptsoft.com). 63 * The implementation was written so as to conform with Netscapes SSL. 64 * 65 * This library is free for commercial and non-commercial use as long as 66 * the following conditions are aheared to. The following conditions 67 * apply to all code found in this distribution, be it the RC4, RSA, 68 * lhash, DES, etc., code; not just the SSL code. The SSL documentation 69 * included with this distribution is covered by the same copyright terms 70 * except that the holder is Tim Hudson (tjh (at) cryptsoft.com). 71 * 72 * Copyright remains Eric Young's, and as such any Copyright notices in 73 * the code are not to be removed. 74 * If this package is used in a product, Eric Young should be given attribution 75 * as the author of the parts of the library used. 76 * This can be in the form of a textual message at program startup or 77 * in documentation (online or textual) provided with the package. 78 * 79 * Redistribution and use in source and binary forms, with or without 80 * modification, are permitted provided that the following conditions 81 * are met: 82 * 1. Redistributions of source code must retain the copyright 83 * notice, this list of conditions and the following disclaimer. 84 * 2. Redistributions in binary form must reproduce the above copyright 85 * notice, this list of conditions and the following disclaimer in the 86 * documentation and/or other materials provided with the distribution. 87 * 3. All advertising materials mentioning features or use of this software 88 * must display the following acknowledgement: 89 * "This product includes cryptographic software written by 90 * Eric Young (eay (at) cryptsoft.com)" 91 * The word 'cryptographic' can be left out if the rouines from the library 92 * being used are not cryptographic related :-). 93 * 4. If you include any Windows specific code (or a derivative thereof) from 94 * the apps directory (application code) you must include an acknowledgement: 95 * "This product includes software written by Tim Hudson (tjh (at) cryptsoft.com)" 96 * 97 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND 98 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 99 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 100 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 101 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 102 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 103 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 104 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 105 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 106 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 107 * SUCH DAMAGE. 108 * 109 * The licence and distribution terms for any publically available version or 110 * derivative of this code cannot be changed. i.e. this code cannot simply be 111 * copied and put under another distribution licence 112 * [including the GNU Public Licence.] 113 */ 114 115 #include <assert.h> 116 #include <stdio.h> 117 #include <string.h> 118 119 #include <openssl/bn.h> 120 #include <openssl/buf.h> 121 #include <openssl/dh.h> 122 #include <openssl/evp.h> 123 #include <openssl/err.h> 124 #include <openssl/md5.h> 125 #include <openssl/mem.h> 126 #include <openssl/obj.h> 127 #include <openssl/rand.h> 128 129 #include "internal.h" 130 131 static int dtls1_get_hello_verify(SSL *s); 132 133 int dtls1_connect(SSL *s) { 134 BUF_MEM *buf = NULL; 135 void (*cb)(const SSL *ssl, int type, int val) = NULL; 136 int ret = -1; 137 int new_state, state, skip = 0; 138 139 assert(s->handshake_func == dtls1_connect); 140 assert(!s->server); 141 assert(SSL_IS_DTLS(s)); 142 143 ERR_clear_error(); 144 ERR_clear_system_error(); 145 146 if (s->info_callback != NULL) { 147 cb = s->info_callback; 148 } else if (s->ctx->info_callback != NULL) { 149 cb = s->ctx->info_callback; 150 } 151 152 s->in_handshake++; 153 154 for (;;) { 155 state = s->state; 156 157 switch (s->state) { 158 case SSL_ST_CONNECT: 159 if (cb != NULL) { 160 cb(s, SSL_CB_HANDSHAKE_START, 1); 161 } 162 163 if (s->init_buf == NULL) { 164 buf = BUF_MEM_new(); 165 if (buf == NULL || 166 !BUF_MEM_grow(buf, SSL3_RT_MAX_PLAIN_LENGTH)) { 167 ret = -1; 168 goto end; 169 } 170 s->init_buf = buf; 171 buf = NULL; 172 } 173 174 if (!ssl_init_wbio_buffer(s, 0)) { 175 ret = -1; 176 goto end; 177 } 178 179 /* don't push the buffering BIO quite yet */ 180 181 s->state = SSL3_ST_CW_CLNT_HELLO_A; 182 s->init_num = 0; 183 s->d1->send_cookie = 0; 184 s->hit = 0; 185 break; 186 187 case SSL3_ST_CW_CLNT_HELLO_A: 188 case SSL3_ST_CW_CLNT_HELLO_B: 189 s->shutdown = 0; 190 191 /* every DTLS ClientHello resets Finished MAC */ 192 if (!ssl3_init_finished_mac(s)) { 193 OPENSSL_PUT_ERROR(SSL, dtls1_connect, ERR_R_INTERNAL_ERROR); 194 ret = -1; 195 goto end; 196 } 197 198 dtls1_start_timer(s); 199 ret = ssl3_send_client_hello(s); 200 if (ret <= 0) { 201 goto end; 202 } 203 204 if (s->d1->send_cookie) { 205 s->state = SSL3_ST_CW_FLUSH; 206 s->s3->tmp.next_state = SSL3_ST_CR_SRVR_HELLO_A; 207 } else { 208 s->state = DTLS1_ST_CR_HELLO_VERIFY_REQUEST_A; 209 } 210 211 s->init_num = 0; 212 /* turn on buffering for the next lot of output */ 213 if (s->bbio != s->wbio) { 214 s->wbio = BIO_push(s->bbio, s->wbio); 215 } 216 217 break; 218 219 case DTLS1_ST_CR_HELLO_VERIFY_REQUEST_A: 220 case DTLS1_ST_CR_HELLO_VERIFY_REQUEST_B: 221 ret = dtls1_get_hello_verify(s); 222 if (ret <= 0) { 223 goto end; 224 } 225 if (s->d1->send_cookie) { 226 /* start again, with a cookie */ 227 dtls1_stop_timer(s); 228 s->state = SSL3_ST_CW_CLNT_HELLO_A; 229 } else { 230 s->state = SSL3_ST_CR_SRVR_HELLO_A; 231 } 232 s->init_num = 0; 233 break; 234 235 case SSL3_ST_CR_SRVR_HELLO_A: 236 case SSL3_ST_CR_SRVR_HELLO_B: 237 ret = ssl3_get_server_hello(s); 238 if (ret <= 0) { 239 goto end; 240 } 241 242 if (s->hit) { 243 s->state = SSL3_ST_CR_FINISHED_A; 244 if (s->tlsext_ticket_expected) { 245 /* receive renewed session ticket */ 246 s->state = SSL3_ST_CR_SESSION_TICKET_A; 247 } 248 } else { 249 s->state = SSL3_ST_CR_CERT_A; 250 } 251 s->init_num = 0; 252 break; 253 254 case SSL3_ST_CR_CERT_A: 255 case SSL3_ST_CR_CERT_B: 256 if (ssl_cipher_has_server_public_key(s->s3->tmp.new_cipher)) { 257 ret = ssl3_get_server_certificate(s); 258 if (ret <= 0) { 259 goto end; 260 } 261 if (s->s3->tmp.certificate_status_expected) { 262 s->state = SSL3_ST_CR_CERT_STATUS_A; 263 } else { 264 s->state = SSL3_ST_CR_KEY_EXCH_A; 265 } 266 } else { 267 skip = 1; 268 s->state = SSL3_ST_CR_KEY_EXCH_A; 269 } 270 s->init_num = 0; 271 break; 272 273 case SSL3_ST_CR_KEY_EXCH_A: 274 case SSL3_ST_CR_KEY_EXCH_B: 275 ret = ssl3_get_server_key_exchange(s); 276 if (ret <= 0) { 277 goto end; 278 } 279 s->state = SSL3_ST_CR_CERT_REQ_A; 280 s->init_num = 0; 281 282 /* at this point we check that we have the 283 * required stuff from the server */ 284 if (!ssl3_check_cert_and_algorithm(s)) { 285 ret = -1; 286 goto end; 287 } 288 break; 289 290 case SSL3_ST_CR_CERT_REQ_A: 291 case SSL3_ST_CR_CERT_REQ_B: 292 ret = ssl3_get_certificate_request(s); 293 if (ret <= 0) { 294 goto end; 295 } 296 s->state = SSL3_ST_CR_SRVR_DONE_A; 297 s->init_num = 0; 298 break; 299 300 case SSL3_ST_CR_SRVR_DONE_A: 301 case SSL3_ST_CR_SRVR_DONE_B: 302 ret = ssl3_get_server_done(s); 303 if (ret <= 0) { 304 goto end; 305 } 306 dtls1_stop_timer(s); 307 if (s->s3->tmp.cert_req) { 308 s->s3->tmp.next_state = SSL3_ST_CW_CERT_A; 309 } else { 310 s->s3->tmp.next_state = SSL3_ST_CW_KEY_EXCH_A; 311 } 312 s->init_num = 0; 313 s->state = s->s3->tmp.next_state; 314 break; 315 316 case SSL3_ST_CW_CERT_A: 317 case SSL3_ST_CW_CERT_B: 318 case SSL3_ST_CW_CERT_C: 319 case SSL3_ST_CW_CERT_D: 320 dtls1_start_timer(s); 321 ret = ssl3_send_client_certificate(s); 322 if (ret <= 0) { 323 goto end; 324 } 325 s->state = SSL3_ST_CW_KEY_EXCH_A; 326 s->init_num = 0; 327 break; 328 329 case SSL3_ST_CW_KEY_EXCH_A: 330 case SSL3_ST_CW_KEY_EXCH_B: 331 dtls1_start_timer(s); 332 ret = ssl3_send_client_key_exchange(s); 333 if (ret <= 0) { 334 goto end; 335 } 336 /* For TLS, cert_req is set to 2, so a cert chain 337 * of nothing is sent, but no verify packet is sent */ 338 if (s->s3->tmp.cert_req == 1) { 339 s->state = SSL3_ST_CW_CERT_VRFY_A; 340 } else { 341 s->state = SSL3_ST_CW_CHANGE_A; 342 s->s3->change_cipher_spec = 0; 343 } 344 345 s->init_num = 0; 346 break; 347 348 case SSL3_ST_CW_CERT_VRFY_A: 349 case SSL3_ST_CW_CERT_VRFY_B: 350 dtls1_start_timer(s); 351 ret = ssl3_send_cert_verify(s); 352 if (ret <= 0) { 353 goto end; 354 } 355 s->state = SSL3_ST_CW_CHANGE_A; 356 s->init_num = 0; 357 s->s3->change_cipher_spec = 0; 358 break; 359 360 case SSL3_ST_CW_CHANGE_A: 361 case SSL3_ST_CW_CHANGE_B: 362 if (!s->hit) { 363 dtls1_start_timer(s); 364 } 365 ret = dtls1_send_change_cipher_spec(s, SSL3_ST_CW_CHANGE_A, 366 SSL3_ST_CW_CHANGE_B); 367 if (ret <= 0) { 368 goto end; 369 } 370 371 s->state = SSL3_ST_CW_FINISHED_A; 372 s->init_num = 0; 373 374 s->session->cipher = s->s3->tmp.new_cipher; 375 if (!s->enc_method->setup_key_block(s) || 376 !s->enc_method->change_cipher_state( 377 s, SSL3_CHANGE_CIPHER_CLIENT_WRITE)) { 378 ret = -1; 379 goto end; 380 } 381 382 dtls1_reset_seq_numbers(s, SSL3_CC_WRITE); 383 break; 384 385 case SSL3_ST_CW_FINISHED_A: 386 case SSL3_ST_CW_FINISHED_B: 387 if (!s->hit) { 388 dtls1_start_timer(s); 389 } 390 391 ret = 392 ssl3_send_finished(s, SSL3_ST_CW_FINISHED_A, SSL3_ST_CW_FINISHED_B, 393 s->enc_method->client_finished_label, 394 s->enc_method->client_finished_label_len); 395 if (ret <= 0) { 396 goto end; 397 } 398 s->state = SSL3_ST_CW_FLUSH; 399 400 if (s->hit) { 401 s->s3->tmp.next_state = SSL_ST_OK; 402 } else { 403 /* Allow NewSessionTicket if ticket expected */ 404 if (s->tlsext_ticket_expected) { 405 s->s3->tmp.next_state = SSL3_ST_CR_SESSION_TICKET_A; 406 } else { 407 s->s3->tmp.next_state = SSL3_ST_CR_FINISHED_A; 408 } 409 } 410 s->init_num = 0; 411 break; 412 413 case SSL3_ST_CR_SESSION_TICKET_A: 414 case SSL3_ST_CR_SESSION_TICKET_B: 415 ret = ssl3_get_new_session_ticket(s); 416 if (ret <= 0) { 417 goto end; 418 } 419 s->state = SSL3_ST_CR_FINISHED_A; 420 s->init_num = 0; 421 break; 422 423 case SSL3_ST_CR_CERT_STATUS_A: 424 case SSL3_ST_CR_CERT_STATUS_B: 425 ret = ssl3_get_cert_status(s); 426 if (ret <= 0) { 427 goto end; 428 } 429 s->state = SSL3_ST_CR_KEY_EXCH_A; 430 s->init_num = 0; 431 break; 432 433 case SSL3_ST_CR_FINISHED_A: 434 case SSL3_ST_CR_FINISHED_B: 435 s->d1->change_cipher_spec_ok = 1; 436 ret = 437 ssl3_get_finished(s, SSL3_ST_CR_FINISHED_A, SSL3_ST_CR_FINISHED_B); 438 if (ret <= 0) { 439 goto end; 440 } 441 dtls1_stop_timer(s); 442 443 if (s->hit) { 444 s->state = SSL3_ST_CW_CHANGE_A; 445 } else { 446 s->state = SSL_ST_OK; 447 } 448 449 s->init_num = 0; 450 break; 451 452 case SSL3_ST_CW_FLUSH: 453 s->rwstate = SSL_WRITING; 454 if (BIO_flush(s->wbio) <= 0) { 455 ret = -1; 456 goto end; 457 } 458 s->rwstate = SSL_NOTHING; 459 s->state = s->s3->tmp.next_state; 460 break; 461 462 case SSL_ST_OK: 463 /* clean a few things up */ 464 ssl3_cleanup_key_block(s); 465 466 /* Remove write buffering now. */ 467 ssl_free_wbio_buffer(s); 468 469 s->init_num = 0; 470 s->s3->initial_handshake_complete = 1; 471 472 ssl_update_cache(s, SSL_SESS_CACHE_CLIENT); 473 474 ret = 1; 475 476 if (cb != NULL) { 477 cb(s, SSL_CB_HANDSHAKE_DONE, 1); 478 } 479 480 /* done with handshaking */ 481 s->d1->handshake_read_seq = 0; 482 s->d1->next_handshake_write_seq = 0; 483 goto end; 484 485 default: 486 OPENSSL_PUT_ERROR(SSL, dtls1_connect, SSL_R_UNKNOWN_STATE); 487 ret = -1; 488 goto end; 489 } 490 491 /* did we do anything? */ 492 if (!s->s3->tmp.reuse_message && !skip) { 493 if ((cb != NULL) && (s->state != state)) { 494 new_state = s->state; 495 s->state = state; 496 cb(s, SSL_CB_CONNECT_LOOP, 1); 497 s->state = new_state; 498 } 499 } 500 skip = 0; 501 } 502 503 end: 504 s->in_handshake--; 505 506 BUF_MEM_free(buf); 507 if (cb != NULL) { 508 cb(s, SSL_CB_CONNECT_EXIT, ret); 509 } 510 return ret; 511 } 512 513 static int dtls1_get_hello_verify(SSL *s) { 514 long n; 515 int al, ok = 0; 516 CBS hello_verify_request, cookie; 517 uint16_t server_version; 518 519 n = s->method->ssl_get_message( 520 s, DTLS1_ST_CR_HELLO_VERIFY_REQUEST_A, DTLS1_ST_CR_HELLO_VERIFY_REQUEST_B, 521 -1, 522 /* Use the same maximum size as ssl3_get_server_hello. */ 523 20000, ssl_hash_message, &ok); 524 525 if (!ok) { 526 return n; 527 } 528 529 if (s->s3->tmp.message_type != DTLS1_MT_HELLO_VERIFY_REQUEST) { 530 s->d1->send_cookie = 0; 531 s->s3->tmp.reuse_message = 1; 532 return 1; 533 } 534 535 CBS_init(&hello_verify_request, s->init_msg, n); 536 537 if (!CBS_get_u16(&hello_verify_request, &server_version) || 538 !CBS_get_u8_length_prefixed(&hello_verify_request, &cookie) || 539 CBS_len(&hello_verify_request) != 0) { 540 al = SSL_AD_DECODE_ERROR; 541 OPENSSL_PUT_ERROR(SSL, dtls1_get_hello_verify, SSL_R_DECODE_ERROR); 542 goto f_err; 543 } 544 545 if (CBS_len(&cookie) > sizeof(s->d1->cookie)) { 546 al = SSL_AD_ILLEGAL_PARAMETER; 547 goto f_err; 548 } 549 550 memcpy(s->d1->cookie, CBS_data(&cookie), CBS_len(&cookie)); 551 s->d1->cookie_len = CBS_len(&cookie); 552 553 s->d1->send_cookie = 1; 554 return 1; 555 556 f_err: 557 ssl3_send_alert(s, SSL3_AL_FATAL, al); 558 return -1; 559 } 560
