1 /* $OpenBSD: d1_lib.c,v 1.29 2015/07/19 20:32:18 doug 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 63 #include <netinet/in.h> 64 65 #include <stdio.h> 66 67 #include <openssl/objects.h> 68 69 #include "pqueue.h" 70 #include "ssl_locl.h" 71 72 int dtls1_listen(SSL *s, struct sockaddr *client); 73 74 SSL3_ENC_METHOD DTLSv1_enc_data = { 75 .enc = dtls1_enc, 76 .mac = tls1_mac, 77 .setup_key_block = tls1_setup_key_block, 78 .generate_master_secret = tls1_generate_master_secret, 79 .change_cipher_state = tls1_change_cipher_state, 80 .final_finish_mac = tls1_final_finish_mac, 81 .finish_mac_length = TLS1_FINISH_MAC_LENGTH, 82 .cert_verify_mac = tls1_cert_verify_mac, 83 .client_finished_label = TLS_MD_CLIENT_FINISH_CONST, 84 .client_finished_label_len = TLS_MD_CLIENT_FINISH_CONST_SIZE, 85 .server_finished_label = TLS_MD_SERVER_FINISH_CONST, 86 .server_finished_label_len = TLS_MD_SERVER_FINISH_CONST_SIZE, 87 .alert_value = tls1_alert_code, 88 .export_keying_material = tls1_export_keying_material, 89 .enc_flags = SSL_ENC_FLAG_DTLS|SSL_ENC_FLAG_EXPLICIT_IV, 90 }; 91 92 long 93 dtls1_default_timeout(void) 94 { 95 /* 2 hours, the 24 hours mentioned in the DTLSv1 spec 96 * is way too long for http, the cache would over fill */ 97 return (60*60*2); 98 } 99 100 int 101 dtls1_new(SSL *s) 102 { 103 DTLS1_STATE *d1; 104 105 if (!ssl3_new(s)) 106 return (0); 107 if ((d1 = calloc(1, sizeof *d1)) == NULL) { 108 ssl3_free(s); 109 return (0); 110 } 111 112 /* d1->handshake_epoch=0; */ 113 114 d1->unprocessed_rcds.q = pqueue_new(); 115 d1->processed_rcds.q = pqueue_new(); 116 d1->buffered_messages = pqueue_new(); 117 d1->sent_messages = pqueue_new(); 118 d1->buffered_app_data.q = pqueue_new(); 119 120 if (s->server) { 121 d1->cookie_len = sizeof(s->d1->cookie); 122 } 123 124 if (!d1->unprocessed_rcds.q || !d1->processed_rcds.q || 125 !d1->buffered_messages || !d1->sent_messages || 126 !d1->buffered_app_data.q) { 127 if (d1->unprocessed_rcds.q) 128 pqueue_free(d1->unprocessed_rcds.q); 129 if (d1->processed_rcds.q) 130 pqueue_free(d1->processed_rcds.q); 131 if (d1->buffered_messages) 132 pqueue_free(d1->buffered_messages); 133 if (d1->sent_messages) 134 pqueue_free(d1->sent_messages); 135 if (d1->buffered_app_data.q) 136 pqueue_free(d1->buffered_app_data.q); 137 free(d1); 138 ssl3_free(s); 139 return (0); 140 } 141 142 s->d1 = d1; 143 s->method->ssl_clear(s); 144 return (1); 145 } 146 147 static void 148 dtls1_clear_queues(SSL *s) 149 { 150 pitem *item = NULL; 151 hm_fragment *frag = NULL; 152 DTLS1_RECORD_DATA *rdata; 153 154 while ((item = pqueue_pop(s->d1->unprocessed_rcds.q)) != NULL) { 155 rdata = (DTLS1_RECORD_DATA *) item->data; 156 free(rdata->rbuf.buf); 157 free(item->data); 158 pitem_free(item); 159 } 160 161 while ((item = pqueue_pop(s->d1->processed_rcds.q)) != NULL) { 162 rdata = (DTLS1_RECORD_DATA *) item->data; 163 free(rdata->rbuf.buf); 164 free(item->data); 165 pitem_free(item); 166 } 167 168 while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) { 169 frag = (hm_fragment *)item->data; 170 free(frag->fragment); 171 free(frag); 172 pitem_free(item); 173 } 174 175 while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) { 176 frag = (hm_fragment *)item->data; 177 free(frag->fragment); 178 free(frag); 179 pitem_free(item); 180 } 181 182 while ((item = pqueue_pop(s->d1->buffered_app_data.q)) != NULL) { 183 rdata = (DTLS1_RECORD_DATA *) item->data; 184 free(rdata->rbuf.buf); 185 free(item->data); 186 pitem_free(item); 187 } 188 } 189 190 void 191 dtls1_free(SSL *s) 192 { 193 if (s == NULL) 194 return; 195 196 ssl3_free(s); 197 198 dtls1_clear_queues(s); 199 200 pqueue_free(s->d1->unprocessed_rcds.q); 201 pqueue_free(s->d1->processed_rcds.q); 202 pqueue_free(s->d1->buffered_messages); 203 pqueue_free(s->d1->sent_messages); 204 pqueue_free(s->d1->buffered_app_data.q); 205 206 OPENSSL_cleanse(s->d1, sizeof *s->d1); 207 free(s->d1); 208 s->d1 = NULL; 209 } 210 211 void 212 dtls1_clear(SSL *s) 213 { 214 pqueue unprocessed_rcds; 215 pqueue processed_rcds; 216 pqueue buffered_messages; 217 pqueue sent_messages; 218 pqueue buffered_app_data; 219 unsigned int mtu; 220 221 if (s->d1) { 222 unprocessed_rcds = s->d1->unprocessed_rcds.q; 223 processed_rcds = s->d1->processed_rcds.q; 224 buffered_messages = s->d1->buffered_messages; 225 sent_messages = s->d1->sent_messages; 226 buffered_app_data = s->d1->buffered_app_data.q; 227 mtu = s->d1->mtu; 228 229 dtls1_clear_queues(s); 230 231 memset(s->d1, 0, sizeof(*(s->d1))); 232 233 if (s->server) { 234 s->d1->cookie_len = sizeof(s->d1->cookie); 235 } 236 237 if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) { 238 s->d1->mtu = mtu; 239 } 240 241 s->d1->unprocessed_rcds.q = unprocessed_rcds; 242 s->d1->processed_rcds.q = processed_rcds; 243 s->d1->buffered_messages = buffered_messages; 244 s->d1->sent_messages = sent_messages; 245 s->d1->buffered_app_data.q = buffered_app_data; 246 } 247 248 ssl3_clear(s); 249 if (s->options & SSL_OP_CISCO_ANYCONNECT) 250 s->version = DTLS1_BAD_VER; 251 else 252 s->version = DTLS1_VERSION; 253 } 254 255 long 256 dtls1_ctrl(SSL *s, int cmd, long larg, void *parg) 257 { 258 int ret = 0; 259 260 switch (cmd) { 261 case DTLS_CTRL_GET_TIMEOUT: 262 if (dtls1_get_timeout(s, (struct timeval*) parg) != NULL) { 263 ret = 1; 264 } 265 break; 266 case DTLS_CTRL_HANDLE_TIMEOUT: 267 ret = dtls1_handle_timeout(s); 268 break; 269 case DTLS_CTRL_LISTEN: 270 ret = dtls1_listen(s, parg); 271 break; 272 273 default: 274 ret = ssl3_ctrl(s, cmd, larg, parg); 275 break; 276 } 277 return (ret); 278 } 279 280 /* 281 * As it's impossible to use stream ciphers in "datagram" mode, this 282 * simple filter is designed to disengage them in DTLS. Unfortunately 283 * there is no universal way to identify stream SSL_CIPHER, so we have 284 * to explicitly list their SSL_* codes. Currently RC4 is the only one 285 * available, but if new ones emerge, they will have to be added... 286 */ 287 const SSL_CIPHER * 288 dtls1_get_cipher(unsigned int u) 289 { 290 const SSL_CIPHER *ciph = ssl3_get_cipher(u); 291 292 if (ciph != NULL) { 293 if (ciph->algorithm_enc == SSL_RC4) 294 return NULL; 295 } 296 297 return ciph; 298 } 299 300 void 301 dtls1_start_timer(SSL *s) 302 { 303 304 /* If timer is not set, initialize duration with 1 second */ 305 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) { 306 s->d1->timeout_duration = 1; 307 } 308 309 /* Set timeout to current time */ 310 gettimeofday(&(s->d1->next_timeout), NULL); 311 312 /* Add duration to current time */ 313 s->d1->next_timeout.tv_sec += s->d1->timeout_duration; 314 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, 315 &(s->d1->next_timeout)); 316 } 317 318 struct timeval* 319 dtls1_get_timeout(SSL *s, struct timeval* timeleft) 320 { 321 struct timeval timenow; 322 323 /* If no timeout is set, just return NULL */ 324 if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) { 325 return NULL; 326 } 327 328 /* Get current time */ 329 gettimeofday(&timenow, NULL); 330 331 /* If timer already expired, set remaining time to 0 */ 332 if (s->d1->next_timeout.tv_sec < timenow.tv_sec || 333 (s->d1->next_timeout.tv_sec == timenow.tv_sec && 334 s->d1->next_timeout.tv_usec <= timenow.tv_usec)) { 335 memset(timeleft, 0, sizeof(struct timeval)); 336 return timeleft; 337 } 338 339 /* Calculate time left until timer expires */ 340 memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval)); 341 timeleft->tv_sec -= timenow.tv_sec; 342 timeleft->tv_usec -= timenow.tv_usec; 343 if (timeleft->tv_usec < 0) { 344 timeleft->tv_sec--; 345 timeleft->tv_usec += 1000000; 346 } 347 348 /* If remaining time is less than 15 ms, set it to 0 349 * to prevent issues because of small devergences with 350 * socket timeouts. 351 */ 352 if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) { 353 memset(timeleft, 0, sizeof(struct timeval)); 354 } 355 356 357 return timeleft; 358 } 359 360 int 361 dtls1_is_timer_expired(SSL *s) 362 { 363 struct timeval timeleft; 364 365 /* Get time left until timeout, return false if no timer running */ 366 if (dtls1_get_timeout(s, &timeleft) == NULL) { 367 return 0; 368 } 369 370 /* Return false if timer is not expired yet */ 371 if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) { 372 return 0; 373 } 374 375 /* Timer expired, so return true */ 376 return 1; 377 } 378 379 void 380 dtls1_double_timeout(SSL *s) 381 { 382 s->d1->timeout_duration *= 2; 383 if (s->d1->timeout_duration > 60) 384 s->d1->timeout_duration = 60; 385 dtls1_start_timer(s); 386 } 387 388 void 389 dtls1_stop_timer(SSL *s) 390 { 391 /* Reset everything */ 392 memset(&(s->d1->timeout), 0, sizeof(struct dtls1_timeout_st)); 393 memset(&(s->d1->next_timeout), 0, sizeof(struct timeval)); 394 s->d1->timeout_duration = 1; 395 BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, 396 &(s->d1->next_timeout)); 397 /* Clear retransmission buffer */ 398 dtls1_clear_record_buffer(s); 399 } 400 401 int 402 dtls1_check_timeout_num(SSL *s) 403 { 404 s->d1->timeout.num_alerts++; 405 406 /* Reduce MTU after 2 unsuccessful retransmissions */ 407 if (s->d1->timeout.num_alerts > 2) { 408 s->d1->mtu = BIO_ctrl(SSL_get_wbio(s), 409 BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL); 410 411 } 412 413 if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) { 414 /* fail the connection, enough alerts have been sent */ 415 SSLerr(SSL_F_DTLS1_CHECK_TIMEOUT_NUM, SSL_R_READ_TIMEOUT_EXPIRED); 416 return -1; 417 } 418 419 return 0; 420 } 421 422 int 423 dtls1_handle_timeout(SSL *s) 424 { 425 /* if no timer is expired, don't do anything */ 426 if (!dtls1_is_timer_expired(s)) { 427 return 0; 428 } 429 430 dtls1_double_timeout(s); 431 432 if (dtls1_check_timeout_num(s) < 0) 433 return -1; 434 435 s->d1->timeout.read_timeouts++; 436 if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) { 437 s->d1->timeout.read_timeouts = 1; 438 } 439 440 dtls1_start_timer(s); 441 return dtls1_retransmit_buffered_messages(s); 442 } 443 444 int 445 dtls1_listen(SSL *s, struct sockaddr *client) 446 { 447 int ret; 448 449 /* Ensure there is no state left over from a previous invocation */ 450 SSL_clear(s); 451 452 SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE); 453 s->d1->listen = 1; 454 455 ret = SSL_accept(s); 456 if (ret <= 0) 457 return ret; 458 459 (void)BIO_dgram_get_peer(SSL_get_rbio(s), client); 460 return 1; 461 } 462 463 void 464 dtls1_build_sequence_number(unsigned char *dst, unsigned char *seq, 465 unsigned short epoch) 466 { 467 unsigned char dtlsseq[SSL3_SEQUENCE_SIZE]; 468 unsigned char *p; 469 470 p = dtlsseq; 471 s2n(epoch, p); 472 memcpy(p, &seq[2], SSL3_SEQUENCE_SIZE - 2); 473 memcpy(dst, dtlsseq, SSL3_SEQUENCE_SIZE); 474 } 475