ssl/d1_lib.c

   1 /* ssl/d1_lib.c */
   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 <stdio.h>
  61 #define USE_SOCKETS
  62 #include <openssl/objects.h>
  63 #include "ssl_locl.h"
  64
  65 #if defined(OPENSSL_SYS_VMS)
  66 # include <sys/timeb.h>
  67 #endif
  68
  69 static void get_current_time(struct timeval *t);
  70 static int dtls1_set_handshake_header(SSL *s, int type, unsigned long len);
  71 static int dtls1_handshake_write(SSL *s);
  72 const char dtls1_version_str[] = "DTLSv1" OPENSSL_VERSION_PTEXT;
  73 int dtls1_listen(SSL *s, struct sockaddr *client);
  74
  75 const SSL3_ENC_METHOD DTLSv1_enc_data = {
  76     tls1_enc,
  77     tls1_mac,
  78     tls1_setup_key_block,
  79     tls1_generate_master_secret,
  80     tls1_change_cipher_state,
  81     tls1_final_finish_mac,
  82     TLS1_FINISH_MAC_LENGTH,
  83     tls1_cert_verify_mac,
  84     TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
  85     TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
  86     tls1_alert_code,
  87     tls1_export_keying_material,
  88     SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV,
  89     DTLS1_HM_HEADER_LENGTH,
  90     dtls1_set_handshake_header,
  91     dtls1_handshake_write
  92 };
  93
  94 const SSL3_ENC_METHOD DTLSv1_2_enc_data = {
  95     tls1_enc,
  96     tls1_mac,
  97     tls1_setup_key_block,
  98     tls1_generate_master_secret,
  99     tls1_change_cipher_state,
 100     tls1_final_finish_mac,
 101     TLS1_FINISH_MAC_LENGTH,
 102     tls1_cert_verify_mac,
 103     TLS_MD_CLIENT_FINISH_CONST, TLS_MD_CLIENT_FINISH_CONST_SIZE,
 104     TLS_MD_SERVER_FINISH_CONST, TLS_MD_SERVER_FINISH_CONST_SIZE,
 105     tls1_alert_code,
 106     tls1_export_keying_material,
 107     SSL_ENC_FLAG_DTLS | SSL_ENC_FLAG_EXPLICIT_IV | SSL_ENC_FLAG_SIGALGS
 108         | SSL_ENC_FLAG_SHA256_PRF | SSL_ENC_FLAG_TLS1_2_CIPHERS,
 109     DTLS1_HM_HEADER_LENGTH,
 110     dtls1_set_handshake_header,
 111     dtls1_handshake_write
 112 };
 113
 114 long dtls1_default_timeout(void)
 115 {
 116     /*
 117      * 2 hours, the 24 hours mentioned in the DTLSv1 spec is way too long for
 118      * http, the cache would over fill
 119      */
 120     return (60 * 60 * 2);
 121 }
 122
 123 int dtls1_new(SSL *s)
 124 {
 125     DTLS1_STATE *d1;
 126
 127     if (!ssl3_new(s))
 128         return (0);
 129     if ((d1 = OPENSSL_malloc(sizeof *d1)) == NULL) {
 130         ssl3_free(s);
 131         return (0);
 132     }
 133     memset(d1, 0, sizeof *d1);
 134
 135     /* d1->handshake_epoch=0; */
 136
 137     d1->unprocessed_rcds.q = pqueue_new();
 138     d1->processed_rcds.q = pqueue_new();
 139     d1->buffered_messages = pqueue_new();
 140     d1->sent_messages = pqueue_new();
 141     d1->buffered_app_data.q = pqueue_new();
 142
 143     if (s->server) {
 144         d1->cookie_len = sizeof(s->d1->cookie);
 145     }
 146
 147     d1->link_mtu = 0;
 148     d1->mtu = 0;
 149
 150     if (!d1->unprocessed_rcds.q || !d1->processed_rcds.q
 151         || !d1->buffered_messages || !d1->sent_messages
 152         || !d1->buffered_app_data.q) {
 153         if (d1->unprocessed_rcds.q)
 154             pqueue_free(d1->unprocessed_rcds.q);
 155         if (d1->processed_rcds.q)
 156             pqueue_free(d1->processed_rcds.q);
 157         if (d1->buffered_messages)
 158             pqueue_free(d1->buffered_messages);
 159         if (d1->sent_messages)
 160             pqueue_free(d1->sent_messages);
 161         if (d1->buffered_app_data.q)
 162             pqueue_free(d1->buffered_app_data.q);
 163         OPENSSL_free(d1);
 164         ssl3_free(s);
 165         return (0);
 166     }
 167
 168     s->d1 = d1;
 169     s->method->ssl_clear(s);
 170     return (1);
 171 }
 172
 173 static void dtls1_clear_queues(SSL *s)
 174 {
 175     pitem *item = NULL;
 176     hm_fragment *frag = NULL;
 177     DTLS1_RECORD_DATA *rdata;
 178
 179     while ((item = pqueue_pop(s->d1->unprocessed_rcds.q)) != NULL) {
 180         rdata = (DTLS1_RECORD_DATA *)item->data;
 181         if (rdata->rbuf.buf) {
 182             OPENSSL_free(rdata->rbuf.buf);
 183         }
 184         OPENSSL_free(item->data);
 185         pitem_free(item);
 186     }
 187
 188     while ((item = pqueue_pop(s->d1->processed_rcds.q)) != NULL) {
 189         rdata = (DTLS1_RECORD_DATA *)item->data;
 190         if (rdata->rbuf.buf) {
 191             OPENSSL_free(rdata->rbuf.buf);
 192         }
 193         OPENSSL_free(item->data);
 194         pitem_free(item);
 195     }
 196
 197     while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) {
 198         frag = (hm_fragment *)item->data;
 199         dtls1_hm_fragment_free(frag);
 200         pitem_free(item);
 201     }
 202
 203     while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) {
 204         frag = (hm_fragment *)item->data;
 205         dtls1_hm_fragment_free(frag);
 206         pitem_free(item);
 207     }
 208
 209     while ((item = pqueue_pop(s->d1->buffered_app_data.q)) != NULL) {
 210         rdata = (DTLS1_RECORD_DATA *)item->data;
 211         if (rdata->rbuf.buf) {
 212             OPENSSL_free(rdata->rbuf.buf);
 213         }
 214         OPENSSL_free(item->data);
 215         pitem_free(item);
 216     }
 217 }
 218
 219 void dtls1_free(SSL *s)
 220 {
 221     ssl3_free(s);
 222
 223     dtls1_clear_queues(s);
 224
 225     pqueue_free(s->d1->unprocessed_rcds.q);
 226     pqueue_free(s->d1->processed_rcds.q);
 227     pqueue_free(s->d1->buffered_messages);
 228     pqueue_free(s->d1->sent_messages);
 229     pqueue_free(s->d1->buffered_app_data.q);
 230
 231     OPENSSL_free(s->d1);
 232     s->d1 = NULL;
 233 }
 234
 235 void dtls1_clear(SSL *s)
 236 {
 237     pqueue unprocessed_rcds;
 238     pqueue processed_rcds;
 239     pqueue buffered_messages;
 240     pqueue sent_messages;
 241     pqueue buffered_app_data;
 242     unsigned int mtu;
 243     unsigned int link_mtu;
 244
 245     if (s->d1) {
 246         unprocessed_rcds = s->d1->unprocessed_rcds.q;
 247         processed_rcds = s->d1->processed_rcds.q;
 248         buffered_messages = s->d1->buffered_messages;
 249         sent_messages = s->d1->sent_messages;
 250         buffered_app_data = s->d1->buffered_app_data.q;
 251         mtu = s->d1->mtu;
 252         link_mtu = s->d1->link_mtu;
 253
 254         dtls1_clear_queues(s);
 255
 256         memset(s->d1, 0, sizeof(*(s->d1)));
 257
 258         if (s->server) {
 259             s->d1->cookie_len = sizeof(s->d1->cookie);
 260         }
 261
 262         if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) {
 263             s->d1->mtu = mtu;
 264             s->d1->link_mtu = link_mtu;
 265         }
 266
 267         s->d1->unprocessed_rcds.q = unprocessed_rcds;
 268         s->d1->processed_rcds.q = processed_rcds;
 269         s->d1->buffered_messages = buffered_messages;
 270         s->d1->sent_messages = sent_messages;
 271         s->d1->buffered_app_data.q = buffered_app_data;
 272     }
 273
 274     ssl3_clear(s);
 275     if (s->options & SSL_OP_CISCO_ANYCONNECT)
 276         s->client_version = s->version = DTLS1_BAD_VER;
 277     else if (s->method->version == DTLS_ANY_VERSION)
 278         s->version = DTLS1_2_VERSION;
 279     else
 280         s->version = s->method->version;
 281 }
 282
 283 long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
 284 {
 285     int ret = 0;
 286
 287     switch (cmd) {
 288     case DTLS_CTRL_GET_TIMEOUT:
 289         if (dtls1_get_timeout(s, (struct timeval *)parg) != NULL) {
 290             ret = 1;
 291         }
 292         break;
 293     case DTLS_CTRL_HANDLE_TIMEOUT:
 294         ret = dtls1_handle_timeout(s);
 295         break;
 296     case DTLS_CTRL_LISTEN:
 297         ret = dtls1_listen(s, parg);
 298         break;
 299     case SSL_CTRL_CHECK_PROTO_VERSION:
 300         /*
 301          * For library-internal use; checks that the current protocol is the
 302          * highest enabled version (according to s->ctx->method, as version
 303          * negotiation may have changed s->method).
 304          */
 305         if (s->version == s->ctx->method->version)
 306             return 1;
 307         /*
 308          * Apparently we're using a version-flexible SSL_METHOD (not at its
 309          * highest protocol version).
 310          */
 311         if (s->ctx->method->version == DTLS_method()->version) {
 312 #if DTLS_MAX_VERSION != DTLS1_2_VERSION
 313 # error Code needs update for DTLS_method() support beyond DTLS1_2_VERSION.
 314 #endif
 315             if (!(s->options & SSL_OP_NO_DTLSv1_2))
 316                 return s->version == DTLS1_2_VERSION;
 317             if (!(s->options & SSL_OP_NO_DTLSv1))
 318                 return s->version == DTLS1_VERSION;
 319         }
 320         return 0;               /* Unexpected state; fail closed. */
 321     case DTLS_CTRL_SET_LINK_MTU:
 322         if (larg < (long)dtls1_link_min_mtu())
 323             return 0;
 324         s->d1->link_mtu = larg;
 325         return 1;
 326     case DTLS_CTRL_GET_LINK_MIN_MTU:
 327         return (long)dtls1_link_min_mtu();
 328     case SSL_CTRL_SET_MTU:
 329         /*
 330          *  We may not have a BIO set yet so can't call dtls1_min_mtu()
 331          *  We'll have to make do with dtls1_link_min_mtu() and max overhead
 332          */
 333         if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD)
 334             return 0;
 335         s->d1->mtu = larg;
 336         return larg;
 337     default:
 338         ret = ssl3_ctrl(s, cmd, larg, parg);
 339         break;
 340     }
 341     return (ret);
 342 }
 343
 344 /*
 345  * As it's impossible to use stream ciphers in "datagram" mode, this
 346  * simple filter is designed to disengage them in DTLS. Unfortunately
 347  * there is no universal way to identify stream SSL_CIPHER, so we have
 348  * to explicitly list their SSL_* codes. Currently RC4 is the only one
 349  * available, but if new ones emerge, they will have to be added...
 350  */
 351 const SSL_CIPHER *dtls1_get_cipher(unsigned int u)
 352 {
 353     const SSL_CIPHER *ciph = ssl3_get_cipher(u);
 354
 355     if (ciph != NULL) {
 356         if (ciph->algorithm_enc == SSL_RC4)
 357             return NULL;
 358     }
 359
 360     return ciph;
 361 }
 362
 363 void dtls1_start_timer(SSL *s)
 364 {
 365 #ifndef OPENSSL_NO_SCTP
 366     /* Disable timer for SCTP */
 367     if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
 368         memset(&(s->d1->next_timeout), 0, sizeof(struct timeval));
 369         return;
 370     }
 371 #endif
 372
 373     /* If timer is not set, initialize duration with 1 second */
 374     if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
 375         s->d1->timeout_duration = 1;
 376     }
 377
 378     /* Set timeout to current time */
 379     get_current_time(&(s->d1->next_timeout));
 380
 381     /* Add duration to current time */
 382     s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
 383     BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
 384              &(s->d1->next_timeout));
 385 }
 386
 387 struct timeval *dtls1_get_timeout(SSL *s, struct timeval *timeleft)
 388 {
 389     struct timeval timenow;
 390
 391     /* If no timeout is set, just return NULL */
 392     if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
 393         return NULL;
 394     }
 395
 396     /* Get current time */
 397     get_current_time(&timenow);
 398
 399     /* If timer already expired, set remaining time to 0 */
 400     if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
 401         (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
 402          s->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
 403         memset(timeleft, 0, sizeof(struct timeval));
 404         return timeleft;
 405     }
 406
 407     /* Calculate time left until timer expires */
 408     memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
 409     timeleft->tv_sec -= timenow.tv_sec;
 410     timeleft->tv_usec -= timenow.tv_usec;
 411     if (timeleft->tv_usec < 0) {
 412         timeleft->tv_sec--;
 413         timeleft->tv_usec += 1000000;
 414     }
 415
 416     /*
 417      * If remaining time is less than 15 ms, set it to 0 to prevent issues
 418      * because of small devergences with socket timeouts.
 419      */
 420     if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) {
 421         memset(timeleft, 0, sizeof(struct timeval));
 422     }
 423
 424     return timeleft;
 425 }
 426
 427 int dtls1_is_timer_expired(SSL *s)
 428 {
 429     struct timeval timeleft;
 430
 431     /* Get time left until timeout, return false if no timer running */
 432     if (dtls1_get_timeout(s, &timeleft) == NULL) {
 433         return 0;
 434     }
 435
 436     /* Return false if timer is not expired yet */
 437     if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
 438         return 0;
 439     }
 440
 441     /* Timer expired, so return true */
 442     return 1;
 443 }
 444
 445 void dtls1_double_timeout(SSL *s)
 446 {
 447     s->d1->timeout_duration *= 2;
 448     if (s->d1->timeout_duration > 60)
 449         s->d1->timeout_duration = 60;
 450     dtls1_start_timer(s);
 451 }
 452
 453 void dtls1_stop_timer(SSL *s)
 454 {
 455     /* Reset everything */
 456     memset(&(s->d1->timeout), 0, sizeof(struct dtls1_timeout_st));
 457     memset(&(s->d1->next_timeout), 0, sizeof(struct timeval));
 458     s->d1->timeout_duration = 1;
 459     BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
 460              &(s->d1->next_timeout));
 461     /* Clear retransmission buffer */
 462     dtls1_clear_record_buffer(s);
 463 }
 464
 465 int dtls1_check_timeout_num(SSL *s)
 466 {
 467     unsigned int mtu;
 468
 469     s->d1->timeout.num_alerts++;
 470
 471     /* Reduce MTU after 2 unsuccessful retransmissions */
 472     if (s->d1->timeout.num_alerts > 2
 473         && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
 474         mtu =
 475             BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0,
 476                      NULL);
 477         if (mtu < s->d1->mtu)
 478             s->d1->mtu = mtu;
 479     }
 480
 481     if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) {
 482         /* fail the connection, enough alerts have been sent */
 483         SSLerr(SSL_F_DTLS1_CHECK_TIMEOUT_NUM, SSL_R_READ_TIMEOUT_EXPIRED);
 484         return -1;
 485     }
 486
 487     return 0;
 488 }
 489
 490 int dtls1_handle_timeout(SSL *s)
 491 {
 492     /* if no timer is expired, don't do anything */
 493     if (!dtls1_is_timer_expired(s)) {
 494         return 0;
 495     }
 496
 497     dtls1_double_timeout(s);
 498
 499     if (dtls1_check_timeout_num(s) < 0)
 500         return -1;
 501
 502     s->d1->timeout.read_timeouts++;
 503     if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) {
 504         s->d1->timeout.read_timeouts = 1;
 505     }
 506 #ifndef OPENSSL_NO_HEARTBEATS
 507     if (s->tlsext_hb_pending) {
 508         s->tlsext_hb_pending = 0;
 509         return dtls1_heartbeat(s);
 510     }
 511 #endif
 512
 513     dtls1_start_timer(s);
 514     return dtls1_retransmit_buffered_messages(s);
 515 }
 516
 517 static void get_current_time(struct timeval *t)
 518 {
 519 #if defined(_WIN32)
 520     SYSTEMTIME st;
 521     union {
 522         unsigned __int64 ul;
 523         FILETIME ft;
 524     } now;
 525
 526     GetSystemTime(&st);
 527     SystemTimeToFileTime(&st, &now.ft);
 528 # ifdef  __MINGW32__
 529     now.ul -= 116444736000000000ULL;
 530 # else
 531     now.ul -= 116444736000000000UI64; /* re-bias to 1/1/1970 */
 532 # endif
 533     t->tv_sec = (long)(now.ul / 10000000);
 534     t->tv_usec = ((int)(now.ul % 10000000)) / 10;
 535 #elif defined(OPENSSL_SYS_VMS)
 536     struct timeb tb;
 537     ftime(&tb);
 538     t->tv_sec = (long)tb.time;
 539     t->tv_usec = (long)tb.millitm * 1000;
 540 #else
 541     gettimeofday(t, NULL);
 542 #endif
 543 }
 544
 545 int dtls1_listen(SSL *s, struct sockaddr *client)
 546 {
 547     int ret;
 548
 549     /* Ensure there is no state left over from a previous invocation */
 550     SSL_clear(s);
 551
 552     SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
 553     s->d1->listen = 1;
 554
 555     ret = SSL_accept(s);
 556     if (ret <= 0)
 557         return ret;
 558
 559     (void)BIO_dgram_get_peer(SSL_get_rbio(s), client);
 560     return 1;
 561 }
 562
 563 static int dtls1_set_handshake_header(SSL *s, int htype, unsigned long len)
 564 {
 565     unsigned char *p = (unsigned char *)s->init_buf->data;
 566     dtls1_set_message_header(s, p, htype, len, 0, len);
 567     s->init_num = (int)len + DTLS1_HM_HEADER_LENGTH;
 568     s->init_off = 0;
 569     /* Buffer the message to handle re-xmits */
 570
 571     if(!dtls1_buffer_message(s, 0))
 572         return 0;
 573
 574     return 1;
 575 }
 576
 577 static int dtls1_handshake_write(SSL *s)
 578 {
 579     return dtls1_do_write(s, SSL3_RT_HANDSHAKE);
 580 }