1 /* 2 * DTLS implementation written by Nagendra Modadugu 3 * (nagendra (at) cs.stanford.edu) for the OpenSSL project 2005. 4 */ 5 /* ==================================================================== 6 * Copyright (c) 1999-2005 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 #include <openssl/base.h> 58 59 #include <stdio.h> 60 61 #if defined(OPENSSL_WINDOWS) 62 #include <sys/timeb.h> 63 #else 64 #include <sys/socket.h> 65 #include <sys/time.h> 66 #endif 67 68 #include <openssl/err.h> 69 #include <openssl/mem.h> 70 #include <openssl/obj.h> 71 72 #include "ssl_locl.h" 73 74 static void get_current_time(OPENSSL_timeval *t); 75 static OPENSSL_timeval* dtls1_get_timeout(SSL *s, OPENSSL_timeval* timeleft); 76 static void dtls1_set_handshake_header(SSL *s, int type, unsigned long len); 77 static int dtls1_handshake_write(SSL *s); 78 int dtls1_listen(SSL *s, struct sockaddr *client); 79 80 SSL3_ENC_METHOD DTLSv1_enc_data={ 81 tls1_enc, 82 tls1_mac, 83 tls1_setup_key_block, 84 tls1_generate_master_secret, 85 tls1_change_cipher_state, 86 tls1_final_finish_mac, 87 TLS1_FINISH_MAC_LENGTH, 88 tls1_cert_verify_mac, 89 TLS_MD_CLIENT_FINISH_CONST,TLS_MD_CLIENT_FINISH_CONST_SIZE, 90 TLS_MD_SERVER_FINISH_CONST,TLS_MD_SERVER_FINISH_CONST_SIZE, 91 tls1_alert_code, 92 tls1_export_keying_material, 93 SSL_ENC_FLAG_DTLS|SSL_ENC_FLAG_EXPLICIT_IV, 94 DTLS1_HM_HEADER_LENGTH, 95 dtls1_set_handshake_header, 96 dtls1_handshake_write 97 }; 98 99 SSL3_ENC_METHOD DTLSv1_2_enc_data={ 100 tls1_enc, 101 tls1_mac, 102 tls1_setup_key_block, 103 tls1_generate_master_secret, 104 tls1_change_cipher_state, 105 tls1_final_finish_mac, 106 TLS1_FINISH_MAC_LENGTH, 107 tls1_cert_verify_mac, 108 TLS_MD_CLIENT_FINISH_CONST,TLS_MD_CLIENT_FINISH_CONST_SIZE, 109 TLS_MD_SERVER_FINISH_CONST,TLS_MD_SERVER_FINISH_CONST_SIZE, 110 tls1_alert_code, 111 tls1_export_keying_material, 112 SSL_ENC_FLAG_DTLS|SSL_ENC_FLAG_EXPLICIT_IV|SSL_ENC_FLAG_SIGALGS 113 |SSL_ENC_FLAG_SHA256_PRF|SSL_ENC_FLAG_TLS1_2_CIPHERS, 114 DTLS1_HM_HEADER_LENGTH, 115 dtls1_set_handshake_header, 116 dtls1_handshake_write 117 }; 118 119 int dtls1_new(SSL *s) 120 { 121 DTLS1_STATE *d1; 122 123 if (!ssl3_new(s)) return(0); 124 if ((d1=OPENSSL_malloc(sizeof *d1)) == NULL) 125 { 126 ssl3_free(s); 127 return (0); 128 } 129 memset(d1,0, sizeof *d1); 130 131 /* d1->handshake_epoch=0; */ 132 133 d1->unprocessed_rcds.q=pqueue_new(); 134 d1->processed_rcds.q=pqueue_new(); 135 d1->buffered_messages = pqueue_new(); 136 d1->sent_messages=pqueue_new(); 137 d1->buffered_app_data.q=pqueue_new(); 138 139 if ( s->server) 140 { 141 d1->cookie_len = sizeof(s->d1->cookie); 142 } 143 144 if( ! d1->unprocessed_rcds.q || ! d1->processed_rcds.q 145 || ! d1->buffered_messages || ! d1->sent_messages || ! d1->buffered_app_data.q) 146 { 147 if ( d1->unprocessed_rcds.q) pqueue_free(d1->unprocessed_rcds.q); 148 if ( d1->processed_rcds.q) pqueue_free(d1->processed_rcds.q); 149 if ( d1->buffered_messages) pqueue_free(d1->buffered_messages); 150 if ( d1->sent_messages) pqueue_free(d1->sent_messages); 151 if ( d1->buffered_app_data.q) pqueue_free(d1->buffered_app_data.q); 152 OPENSSL_free(d1); 153 ssl3_free(s); 154 return (0); 155 } 156 157 s->d1=d1; 158 s->method->ssl_clear(s); 159 return(1); 160 } 161 162 static void dtls1_clear_queues(SSL *s) 163 { 164 pitem *item = NULL; 165 hm_fragment *frag = NULL; 166 DTLS1_RECORD_DATA *rdata; 167 168 while( (item = pqueue_pop(s->d1->unprocessed_rcds.q)) != NULL) 169 { 170 rdata = (DTLS1_RECORD_DATA *) item->data; 171 if (rdata->rbuf.buf) 172 { 173 OPENSSL_free(rdata->rbuf.buf); 174 } 175 OPENSSL_free(item->data); 176 pitem_free(item); 177 } 178 179 while( (item = pqueue_pop(s->d1->processed_rcds.q)) != NULL) 180 { 181 rdata = (DTLS1_RECORD_DATA *) item->data; 182 if (rdata->rbuf.buf) 183 { 184 OPENSSL_free(rdata->rbuf.buf); 185 } 186 OPENSSL_free(item->data); 187 pitem_free(item); 188 } 189 190 while( (item = pqueue_pop(s->d1->buffered_messages)) != NULL) 191 { 192 frag = (hm_fragment *)item->data; 193 OPENSSL_free(frag->fragment); 194 OPENSSL_free(frag); 195 pitem_free(item); 196 } 197 198 while ( (item = pqueue_pop(s->d1->sent_messages)) != NULL) 199 { 200 frag = (hm_fragment *)item->data; 201 OPENSSL_free(frag->fragment); 202 OPENSSL_free(frag); 203 pitem_free(item); 204 } 205 206 while ( (item = pqueue_pop(s->d1->buffered_app_data.q)) != NULL) 207 { 208 rdata = (DTLS1_RECORD_DATA *) item->data; 209 if (rdata->rbuf.buf) 210 { 211 OPENSSL_free(rdata->rbuf.buf); 212 } 213 OPENSSL_free(item->data); 214 pitem_free(item); 215 } 216 } 217 218 void dtls1_free(SSL *s) 219 { 220 ssl3_free(s); 221 222 dtls1_clear_queues(s); 223 224 pqueue_free(s->d1->unprocessed_rcds.q); 225 pqueue_free(s->d1->processed_rcds.q); 226 pqueue_free(s->d1->buffered_messages); 227 pqueue_free(s->d1->sent_messages); 228 pqueue_free(s->d1->buffered_app_data.q); 229 230 OPENSSL_free(s->d1); 231 s->d1 = NULL; 232 } 233 234 void dtls1_clear(SSL *s) 235 { 236 pqueue unprocessed_rcds; 237 pqueue processed_rcds; 238 pqueue buffered_messages; 239 pqueue sent_messages; 240 pqueue buffered_app_data; 241 unsigned int mtu; 242 243 if (s->d1) 244 { 245 unprocessed_rcds = s->d1->unprocessed_rcds.q; 246 processed_rcds = s->d1->processed_rcds.q; 247 buffered_messages = s->d1->buffered_messages; 248 sent_messages = s->d1->sent_messages; 249 buffered_app_data = s->d1->buffered_app_data.q; 250 mtu = s->d1->mtu; 251 252 dtls1_clear_queues(s); 253 254 memset(s->d1, 0, sizeof(*(s->d1))); 255 256 if (s->server) 257 { 258 s->d1->cookie_len = sizeof(s->d1->cookie); 259 } 260 261 if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) 262 { 263 s->d1->mtu = mtu; 264 } 265 266 s->d1->unprocessed_rcds.q = unprocessed_rcds; 267 s->d1->processed_rcds.q = processed_rcds; 268 s->d1->buffered_messages = buffered_messages; 269 s->d1->sent_messages = sent_messages; 270 s->d1->buffered_app_data.q = buffered_app_data; 271 } 272 273 ssl3_clear(s); 274 if (s->method->version == DTLS_ANY_VERSION) 275 s->version=DTLS1_2_VERSION; 276 else 277 s->version=s->method->version; 278 } 279 280 long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg) 281 { 282 int ret=0; 283 284 switch (cmd) 285 { 286 case DTLS_CTRL_GET_TIMEOUT: 287 if (dtls1_get_timeout(s, (OPENSSL_timeval*) parg) != NULL) 288 { 289 ret = 1; 290 } 291 break; 292 case DTLS_CTRL_HANDLE_TIMEOUT: 293 ret = dtls1_handle_timeout(s); 294 break; 295 case DTLS_CTRL_LISTEN: 296 ret = dtls1_listen(s, parg); 297 break; 298 299 default: 300 ret = ssl3_ctrl(s, cmd, larg, parg); 301 break; 302 } 303 return(ret); 304 } 305 306 /* 307 * As it's impossible to use stream ciphers in "datagram" mode, this 308 * simple filter is designed to disengage them in DTLS. Unfortunately 309 * there is no universal way to identify stream SSL_CIPHER, so we have 310 * to explicitly list their SSL_* codes. Currently RC4 is the only one 311 * available, but if new ones emerge, they will have to be added... 312 */ 313 const SSL_CIPHER *dtls1_get_cipher(unsigned int u) 314 { 315 const SSL_CIPHER *ciph = ssl3_get_cipher(u); 316 317 if (ciph != NULL) 318 { 319 if (ciph->algorithm_enc == SSL_RC4) 320 return NULL; 321 } 322 323 return ciph; 324 } 325 326 void dtls1_start_timer(SSL *s) 327 { 328 /* If timer is not set, initialize duration with 1 second */ 329 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) 330 { 331 s->d1->timeout_duration = 1; 332 } 333 334 /* Set timeout to current time */ 335 get_current_time(&s->d1->next_timeout); 336 337 /* Add duration to current time */ 338 s->d1->next_timeout.tv_sec += s->d1->timeout_duration; 339 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, &s->d1->next_timeout); 340 } 341 342 static OPENSSL_timeval* dtls1_get_timeout(SSL *s, OPENSSL_timeval* timeleft) 343 { 344 OPENSSL_timeval timenow; 345 346 /* If no timeout is set, just return NULL */ 347 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) 348 { 349 return NULL; 350 } 351 352 /* Get current time */ 353 get_current_time(&timenow); 354 355 /* If timer already expired, set remaining time to 0 */ 356 if (s->d1->next_timeout.tv_sec < timenow.tv_sec || 357 (s->d1->next_timeout.tv_sec == timenow.tv_sec && 358 s->d1->next_timeout.tv_usec <= timenow.tv_usec)) 359 { 360 memset(timeleft, 0, sizeof(OPENSSL_timeval)); 361 return timeleft; 362 } 363 364 /* Calculate time left until timer expires */ 365 memcpy(timeleft, &s->d1->next_timeout, sizeof(OPENSSL_timeval)); 366 timeleft->tv_sec -= timenow.tv_sec; 367 timeleft->tv_usec -= timenow.tv_usec; 368 if (timeleft->tv_usec < 0) 369 { 370 timeleft->tv_sec--; 371 timeleft->tv_usec += 1000000; 372 } 373 374 /* If remaining time is less than 15 ms, set it to 0 375 * to prevent issues because of small devergences with 376 * socket timeouts. 377 */ 378 if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) 379 { 380 memset(timeleft, 0, sizeof(OPENSSL_timeval)); 381 } 382 383 384 return timeleft; 385 } 386 387 int dtls1_is_timer_expired(SSL *s) 388 { 389 OPENSSL_timeval timeleft; 390 391 /* Get time left until timeout, return false if no timer running */ 392 if (dtls1_get_timeout(s, &timeleft) == NULL) 393 { 394 return 0; 395 } 396 397 /* Return false if timer is not expired yet */ 398 if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) 399 { 400 return 0; 401 } 402 403 /* Timer expired, so return true */ 404 return 1; 405 } 406 407 void dtls1_double_timeout(SSL *s) 408 { 409 s->d1->timeout_duration *= 2; 410 if (s->d1->timeout_duration > 60) 411 s->d1->timeout_duration = 60; 412 dtls1_start_timer(s); 413 } 414 415 void dtls1_stop_timer(SSL *s) 416 { 417 /* Reset everything */ 418 memset(&(s->d1->timeout), 0, sizeof(struct dtls1_timeout_st)); 419 memset(&s->d1->next_timeout, 0, sizeof(OPENSSL_timeval)); 420 s->d1->timeout_duration = 1; 421 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, &s->d1->next_timeout); 422 /* Clear retransmission buffer */ 423 dtls1_clear_record_buffer(s); 424 } 425 426 int dtls1_check_timeout_num(SSL *s) 427 { 428 s->d1->timeout.num_alerts++; 429 430 /* Reduce MTU after 2 unsuccessful retransmissions */ 431 if (s->d1->timeout.num_alerts > 2) 432 { 433 s->d1->mtu = BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL); 434 } 435 436 if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) 437 { 438 /* fail the connection, enough alerts have been sent */ 439 OPENSSL_PUT_ERROR(SSL, dtls1_check_timeout_num, SSL_R_READ_TIMEOUT_EXPIRED); 440 return -1; 441 } 442 443 return 0; 444 } 445 446 int dtls1_handle_timeout(SSL *s) 447 { 448 /* if no timer is expired, don't do anything */ 449 if (!dtls1_is_timer_expired(s)) 450 { 451 return 0; 452 } 453 454 dtls1_double_timeout(s); 455 456 if (dtls1_check_timeout_num(s) < 0) 457 return -1; 458 459 s->d1->timeout.read_timeouts++; 460 if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) 461 { 462 s->d1->timeout.read_timeouts = 1; 463 } 464 465 dtls1_start_timer(s); 466 return dtls1_retransmit_buffered_messages(s); 467 } 468 469 static void get_current_time(OPENSSL_timeval *t) 470 { 471 #if defined(OPENSSL_WINDOWS) 472 struct _timeb time; 473 _ftime(&time); 474 t->tv_sec = time.time; 475 t->tv_usec = time.millitm * 1000; 476 #else 477 gettimeofday(t, NULL); 478 #endif 479 } 480 481 int dtls1_listen(SSL *s, struct sockaddr *client) 482 { 483 int ret; 484 485 SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE); 486 s->d1->listen = 1; 487 488 ret = SSL_accept(s); 489 if (ret <= 0) return ret; 490 491 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_GET_PEER, 0, &client); 492 return 1; 493 } 494 495 static void dtls1_set_handshake_header(SSL *s, int htype, unsigned long len) 496 { 497 unsigned char *p = (unsigned char *)s->init_buf->data; 498 dtls1_set_message_header(s, p, htype, len, 0, len); 499 s->init_num = (int)len + DTLS1_HM_HEADER_LENGTH; 500 s->init_off = 0; 501 /* Buffer the message to handle re-xmits */ 502 dtls1_buffer_message(s, 0); 503 } 504 505 static int dtls1_handshake_write(SSL *s) 506 { 507 return dtls1_do_write(s, SSL3_RT_HANDSHAKE); 508 } 509
