1 /* $OpenBSD: d1_lib.c,v 1.32 2015/10/07 13:20:48 bcook Exp $ */ 2 /* 3 * DTLS implementation written by Nagendra Modadugu 4 * (nagendra@cs.stanford.edu) for the OpenSSL project 2005. 5 */ 6 /* ==================================================================== 7 * Copyright (c) 1999-2005 The OpenSSL Project. All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in 18 * the documentation and/or other materials provided with the 19 * distribution. 20 * 21 * 3. All advertising materials mentioning features or use of this 22 * software must display the following acknowledgment: 23 * "This product includes software developed by the OpenSSL Project 24 * for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)" 25 * 26 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 27 * endorse or promote products derived from this software without 28 * prior written permission. For written permission, please contact 29 * openssl-core@OpenSSL.org. 30 * 31 * 5. Products derived from this software may not be called "OpenSSL" 32 * nor may "OpenSSL" appear in their names without prior written 33 * permission of the OpenSSL Project. 34 * 35 * 6. Redistributions of any form whatsoever must retain the following 36 * acknowledgment: 37 * "This product includes software developed by the OpenSSL Project 38 * for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)" 39 * 40 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 41 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 43 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 44 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 45 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 46 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 47 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 49 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 50 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 51 * OF THE POSSIBILITY OF SUCH DAMAGE. 52 * ==================================================================== 53 * 54 * This product includes cryptographic software written by Eric Young 55 * (eay@cryptsoft.com). This product includes software written by Tim 56 * Hudson (tjh@cryptsoft.com). 57 * 58 */ 59 60 #include <sys/types.h> 61 #include <sys/socket.h> 62 #include <sys/time.h> 63 64 #include <netinet/in.h> 65 66 #include <stdio.h> 67 68 #include <openssl/objects.h> 69 70 #include "pqueue.h" 71 #include "ssl_locl.h" 72 73 int dtls1_listen(SSL *s, struct sockaddr *client); 74 75 SSL3_ENC_METHOD DTLSv1_enc_data = { 76 .enc = dtls1_enc, 77 .mac = tls1_mac, 78 .setup_key_block = tls1_setup_key_block, 79 .generate_master_secret = tls1_generate_master_secret, 80 .change_cipher_state = tls1_change_cipher_state, 81 .final_finish_mac = tls1_final_finish_mac, 82 .finish_mac_length = TLS1_FINISH_MAC_LENGTH, 83 .cert_verify_mac = tls1_cert_verify_mac, 84 .client_finished_label = TLS_MD_CLIENT_FINISH_CONST, 85 .client_finished_label_len = TLS_MD_CLIENT_FINISH_CONST_SIZE, 86 .server_finished_label = TLS_MD_SERVER_FINISH_CONST, 87 .server_finished_label_len = TLS_MD_SERVER_FINISH_CONST_SIZE, 88 .alert_value = tls1_alert_code, 89 .export_keying_material = tls1_export_keying_material, 90 .enc_flags = SSL_ENC_FLAG_DTLS|SSL_ENC_FLAG_EXPLICIT_IV, 91 }; 92 93 long 94 dtls1_default_timeout(void) 95 { 96 /* 2 hours, the 24 hours mentioned in the DTLSv1 spec 97 * is way too long for http, the cache would over fill */ 98 return (60*60*2); 99 } 100 101 int 102 dtls1_new(SSL *s) 103 { 104 DTLS1_STATE *d1; 105 106 if (!ssl3_new(s)) 107 return (0); 108 if ((d1 = calloc(1, sizeof *d1)) == NULL) { 109 ssl3_free(s); 110 return (0); 111 } 112 113 /* d1->handshake_epoch=0; */ 114 115 d1->unprocessed_rcds.q = pqueue_new(); 116 d1->processed_rcds.q = pqueue_new(); 117 d1->buffered_messages = pqueue_new(); 118 d1->sent_messages = pqueue_new(); 119 d1->buffered_app_data.q = pqueue_new(); 120 121 if (s->server) { 122 d1->cookie_len = sizeof(s->d1->cookie); 123 } 124 125 if (!d1->unprocessed_rcds.q || !d1->processed_rcds.q || 126 !d1->buffered_messages || !d1->sent_messages || 127 !d1->buffered_app_data.q) { 128 pqueue_free(d1->unprocessed_rcds.q); 129 pqueue_free(d1->processed_rcds.q); 130 pqueue_free(d1->buffered_messages); 131 pqueue_free(d1->sent_messages); 132 pqueue_free(d1->buffered_app_data.q); 133 free(d1); 134 ssl3_free(s); 135 return (0); 136 } 137 138 s->d1 = d1; 139 s->method->ssl_clear(s); 140 return (1); 141 } 142 143 static void 144 dtls1_clear_queues(SSL *s) 145 { 146 pitem *item = NULL; 147 hm_fragment *frag = NULL; 148 DTLS1_RECORD_DATA *rdata; 149 150 while ((item = pqueue_pop(s->d1->unprocessed_rcds.q)) != NULL) { 151 rdata = (DTLS1_RECORD_DATA *) item->data; 152 free(rdata->rbuf.buf); 153 free(item->data); 154 pitem_free(item); 155 } 156 157 while ((item = pqueue_pop(s->d1->processed_rcds.q)) != NULL) { 158 rdata = (DTLS1_RECORD_DATA *) item->data; 159 free(rdata->rbuf.buf); 160 free(item->data); 161 pitem_free(item); 162 } 163 164 while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) { 165 frag = (hm_fragment *)item->data; 166 free(frag->fragment); 167 free(frag); 168 pitem_free(item); 169 } 170 171 while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) { 172 frag = (hm_fragment *)item->data; 173 free(frag->fragment); 174 free(frag); 175 pitem_free(item); 176 } 177 178 while ((item = pqueue_pop(s->d1->buffered_app_data.q)) != NULL) { 179 rdata = (DTLS1_RECORD_DATA *) item->data; 180 free(rdata->rbuf.buf); 181 free(item->data); 182 pitem_free(item); 183 } 184 } 185 186 void 187 dtls1_free(SSL *s) 188 { 189 if (s == NULL) 190 return; 191 192 ssl3_free(s); 193 194 dtls1_clear_queues(s); 195 196 pqueue_free(s->d1->unprocessed_rcds.q); 197 pqueue_free(s->d1->processed_rcds.q); 198 pqueue_free(s->d1->buffered_messages); 199 pqueue_free(s->d1->sent_messages); 200 pqueue_free(s->d1->buffered_app_data.q); 201 202 explicit_bzero(s->d1, sizeof *s->d1); 203 free(s->d1); 204 s->d1 = NULL; 205 } 206 207 void 208 dtls1_clear(SSL *s) 209 { 210 pqueue unprocessed_rcds; 211 pqueue processed_rcds; 212 pqueue buffered_messages; 213 pqueue sent_messages; 214 pqueue buffered_app_data; 215 unsigned int mtu; 216 217 if (s->d1) { 218 unprocessed_rcds = s->d1->unprocessed_rcds.q; 219 processed_rcds = s->d1->processed_rcds.q; 220 buffered_messages = s->d1->buffered_messages; 221 sent_messages = s->d1->sent_messages; 222 buffered_app_data = s->d1->buffered_app_data.q; 223 mtu = s->d1->mtu; 224 225 dtls1_clear_queues(s); 226 227 memset(s->d1, 0, sizeof(*(s->d1))); 228 229 if (s->server) { 230 s->d1->cookie_len = sizeof(s->d1->cookie); 231 } 232 233 if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) { 234 s->d1->mtu = mtu; 235 } 236 237 s->d1->unprocessed_rcds.q = unprocessed_rcds; 238 s->d1->processed_rcds.q = processed_rcds; 239 s->d1->buffered_messages = buffered_messages; 240 s->d1->sent_messages = sent_messages; 241 s->d1->buffered_app_data.q = buffered_app_data; 242 } 243 244 ssl3_clear(s); 245 246 s->version = DTLS1_VERSION; 247 } 248 249 long 250 dtls1_ctrl(SSL *s, int cmd, long larg, void *parg) 251 { 252 int ret = 0; 253 254 switch (cmd) { 255 case DTLS_CTRL_GET_TIMEOUT: 256 if (dtls1_get_timeout(s, (struct timeval*) parg) != NULL) { 257 ret = 1; 258 } 259 break; 260 case DTLS_CTRL_HANDLE_TIMEOUT: 261 ret = dtls1_handle_timeout(s); 262 break; 263 case DTLS_CTRL_LISTEN: 264 ret = dtls1_listen(s, parg); 265 break; 266 267 default: 268 ret = ssl3_ctrl(s, cmd, larg, parg); 269 break; 270 } 271 return (ret); 272 } 273 274 /* 275 * As it's impossible to use stream ciphers in "datagram" mode, this 276 * simple filter is designed to disengage them in DTLS. Unfortunately 277 * there is no universal way to identify stream SSL_CIPHER, so we have 278 * to explicitly list their SSL_* codes. Currently RC4 is the only one 279 * available, but if new ones emerge, they will have to be added... 280 */ 281 const SSL_CIPHER * 282 dtls1_get_cipher(unsigned int u) 283 { 284 const SSL_CIPHER *ciph = ssl3_get_cipher(u); 285 286 if (ciph != NULL) { 287 if (ciph->algorithm_enc == SSL_RC4) 288 return NULL; 289 } 290 291 return ciph; 292 } 293 294 void 295 dtls1_start_timer(SSL *s) 296 { 297 298 /* If timer is not set, initialize duration with 1 second */ 299 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) { 300 s->d1->timeout_duration = 1; 301 } 302 303 /* Set timeout to current time */ 304 gettimeofday(&(s->d1->next_timeout), NULL); 305 306 /* Add duration to current time */ 307 s->d1->next_timeout.tv_sec += s->d1->timeout_duration; 308 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, 309 &(s->d1->next_timeout)); 310 } 311 312 struct timeval* 313 dtls1_get_timeout(SSL *s, struct timeval* timeleft) 314 { 315 struct timeval timenow; 316 317 /* If no timeout is set, just return NULL */ 318 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) { 319 return NULL; 320 } 321 322 /* Get current time */ 323 gettimeofday(&timenow, NULL); 324 325 /* If timer already expired, set remaining time to 0 */ 326 if (s->d1->next_timeout.tv_sec < timenow.tv_sec || 327 (s->d1->next_timeout.tv_sec == timenow.tv_sec && 328 s->d1->next_timeout.tv_usec <= timenow.tv_usec)) { 329 memset(timeleft, 0, sizeof(struct timeval)); 330 return timeleft; 331 } 332 333 /* Calculate time left until timer expires */ 334 memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval)); 335 timeleft->tv_sec -= timenow.tv_sec; 336 timeleft->tv_usec -= timenow.tv_usec; 337 if (timeleft->tv_usec < 0) { 338 timeleft->tv_sec--; 339 timeleft->tv_usec += 1000000; 340 } 341 342 /* If remaining time is less than 15 ms, set it to 0 343 * to prevent issues because of small devergences with 344 * socket timeouts. 345 */ 346 if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) { 347 memset(timeleft, 0, sizeof(struct timeval)); 348 } 349 350 351 return timeleft; 352 } 353 354 int 355 dtls1_is_timer_expired(SSL *s) 356 { 357 struct timeval timeleft; 358 359 /* Get time left until timeout, return false if no timer running */ 360 if (dtls1_get_timeout(s, &timeleft) == NULL) { 361 return 0; 362 } 363 364 /* Return false if timer is not expired yet */ 365 if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) { 366 return 0; 367 } 368 369 /* Timer expired, so return true */ 370 return 1; 371 } 372 373 void 374 dtls1_double_timeout(SSL *s) 375 { 376 s->d1->timeout_duration *= 2; 377 if (s->d1->timeout_duration > 60) 378 s->d1->timeout_duration = 60; 379 dtls1_start_timer(s); 380 } 381 382 void 383 dtls1_stop_timer(SSL *s) 384 { 385 /* Reset everything */ 386 memset(&(s->d1->timeout), 0, sizeof(struct dtls1_timeout_st)); 387 memset(&(s->d1->next_timeout), 0, sizeof(struct timeval)); 388 s->d1->timeout_duration = 1; 389 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, 390 &(s->d1->next_timeout)); 391 /* Clear retransmission buffer */ 392 dtls1_clear_record_buffer(s); 393 } 394 395 int 396 dtls1_check_timeout_num(SSL *s) 397 { 398 s->d1->timeout.num_alerts++; 399 400 /* Reduce MTU after 2 unsuccessful retransmissions */ 401 if (s->d1->timeout.num_alerts > 2) { 402 s->d1->mtu = BIO_ctrl(SSL_get_wbio(s), 403 BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL); 404 405 } 406 407 if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) { 408 /* fail the connection, enough alerts have been sent */ 409 SSLerr(SSL_F_DTLS1_CHECK_TIMEOUT_NUM, SSL_R_READ_TIMEOUT_EXPIRED); 410 return -1; 411 } 412 413 return 0; 414 } 415 416 int 417 dtls1_handle_timeout(SSL *s) 418 { 419 /* if no timer is expired, don't do anything */ 420 if (!dtls1_is_timer_expired(s)) { 421 return 0; 422 } 423 424 dtls1_double_timeout(s); 425 426 if (dtls1_check_timeout_num(s) < 0) 427 return -1; 428 429 s->d1->timeout.read_timeouts++; 430 if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) { 431 s->d1->timeout.read_timeouts = 1; 432 } 433 434 dtls1_start_timer(s); 435 return dtls1_retransmit_buffered_messages(s); 436 } 437 438 int 439 dtls1_listen(SSL *s, struct sockaddr *client) 440 { 441 int ret; 442 443 /* Ensure there is no state left over from a previous invocation */ 444 SSL_clear(s); 445 446 SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE); 447 s->d1->listen = 1; 448 449 ret = SSL_accept(s); 450 if (ret <= 0) 451 return ret; 452 453 (void)BIO_dgram_get_peer(SSL_get_rbio(s), client); 454 return 1; 455 } 456 457 void 458 dtls1_build_sequence_number(unsigned char *dst, unsigned char *seq, 459 unsigned short epoch) 460 { 461 unsigned char dtlsseq[SSL3_SEQUENCE_SIZE]; 462 unsigned char *p; 463 464 p = dtlsseq; 465 s2n(epoch, p); 466 memcpy(p, &seq[2], SSL3_SEQUENCE_SIZE - 2); 467 memcpy(dst, dtlsseq, SSL3_SEQUENCE_SIZE); 468 } 469