crypto/libressl/ssl/d1_lib.c

   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 }