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 #elif defined(OPENSSL_SYS_NETWARE) && !defined(_WINSOCK2API_)
  68 # include <sys/timeval.h>
  69 #elif defined(OPENSSL_SYS_VXWORKS)
  70 # include <sys/times.h>
  71 #elif !defined(OPENSSL_SYS_WIN32)
  72 # include <sys/time.h>
  73 #endif
  74
  75 static void get_current_time(struct timeval *t);
  76 static int 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 const 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 const 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 long dtls1_default_timeout(void)
 120 {
 121     /*
 122      * 2 hours, the 24 hours mentioned in the DTLSv1 spec is way too long for
 123      * http, the cache would over fill
 124      */
 125     return (60 * 60 * 2);
 126 }
 127
 128 int dtls1_new(SSL *s)
 129 {
 130     DTLS1_STATE *d1;
 131
 132     if (!DTLS_RECORD_LAYER_new(&s->rlayer)) {
 133         return 0;
 134     }
 135
 136     if (!ssl3_new(s))
 137         return (0);
 138     if ((d1 = OPENSSL_malloc(sizeof(*d1))) == NULL) {
 139         ssl3_free(s);
 140         return (0);
 141     }
 142     memset(d1, 0, sizeof(*d1));
 143
 144     d1->buffered_messages = pqueue_new();
 145     d1->sent_messages = pqueue_new();
 146
 147     if (s->server) {
 148         d1->cookie_len = sizeof(s->d1->cookie);
 149     }
 150
 151     d1->link_mtu = 0;
 152     d1->mtu = 0;
 153
 154     if (!d1->buffered_messages || !d1->sent_messages) {
 155         pqueue_free(d1->buffered_messages);
 156         pqueue_free(d1->sent_messages);
 157         OPENSSL_free(d1);
 158         ssl3_free(s);
 159         return (0);
 160     }
 161
 162     s->d1 = d1;
 163     s->method->ssl_clear(s);
 164     return (1);
 165 }
 166
 167 static void dtls1_clear_queues(SSL *s)
 168 {
 169     pitem *item = NULL;
 170     hm_fragment *frag = NULL;
 171
 172     while ((item = pqueue_pop(s->d1->buffered_messages)) != NULL) {
 173         frag = (hm_fragment *)item->data;
 174         dtls1_hm_fragment_free(frag);
 175         pitem_free(item);
 176     }
 177
 178     while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) {
 179         frag = (hm_fragment *)item->data;
 180         dtls1_hm_fragment_free(frag);
 181         pitem_free(item);
 182     }
 183 }
 184
 185 void dtls1_free(SSL *s)
 186 {
 187     DTLS_RECORD_LAYER_free(&s->rlayer);
 188
 189     ssl3_free(s);
 190
 191     dtls1_clear_queues(s);
 192
 193     pqueue_free(s->d1->buffered_messages);
 194     pqueue_free(s->d1->sent_messages);
 195
 196     OPENSSL_free(s->d1);
 197     s->d1 = NULL;
 198 }
 199
 200 void dtls1_clear(SSL *s)
 201 {
 202     pqueue buffered_messages;
 203     pqueue sent_messages;
 204     unsigned int mtu;
 205     unsigned int link_mtu;
 206
 207     DTLS_RECORD_LAYER_clear(&s->rlayer);
 208
 209     if (s->d1) {
 210         buffered_messages = s->d1->buffered_messages;
 211         sent_messages = s->d1->sent_messages;
 212         mtu = s->d1->mtu;
 213         link_mtu = s->d1->link_mtu;
 214
 215         dtls1_clear_queues(s);
 216
 217         memset(s->d1, 0, sizeof(*s->d1));
 218
 219         if (s->server) {
 220             s->d1->cookie_len = sizeof(s->d1->cookie);
 221         }
 222
 223         if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) {
 224             s->d1->mtu = mtu;
 225             s->d1->link_mtu = link_mtu;
 226         }
 227
 228         s->d1->buffered_messages = buffered_messages;
 229         s->d1->sent_messages = sent_messages;
 230     }
 231
 232     ssl3_clear(s);
 233     if (s->options & SSL_OP_CISCO_ANYCONNECT)
 234         s->client_version = s->version = DTLS1_BAD_VER;
 235     else if (s->method->version == DTLS_ANY_VERSION)
 236         s->version = DTLS1_2_VERSION;
 237     else
 238         s->version = s->method->version;
 239 }
 240
 241 long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
 242 {
 243     int ret = 0;
 244
 245     switch (cmd) {
 246     case DTLS_CTRL_GET_TIMEOUT:
 247         if (dtls1_get_timeout(s, (struct timeval *)parg) != NULL) {
 248             ret = 1;
 249         }
 250         break;
 251     case DTLS_CTRL_HANDLE_TIMEOUT:
 252         ret = dtls1_handle_timeout(s);
 253         break;
 254     case DTLS_CTRL_LISTEN:
 255         ret = dtls1_listen(s, parg);
 256         break;
 257     case SSL_CTRL_CHECK_PROTO_VERSION:
 258         /*
 259          * For library-internal use; checks that the current protocol is the
 260          * highest enabled version (according to s->ctx->method, as version
 261          * negotiation may have changed s->method).
 262          */
 263         if (s->version == s->ctx->method->version)
 264             return 1;
 265         /*
 266          * Apparently we're using a version-flexible SSL_METHOD (not at its
 267          * highest protocol version).
 268          */
 269         if (s->ctx->method->version == DTLS_method()->version) {
 270 #if DTLS_MAX_VERSION != DTLS1_2_VERSION
 271 # error Code needs update for DTLS_method() support beyond DTLS1_2_VERSION.
 272 #endif
 273             if (!(s->options & SSL_OP_NO_DTLSv1_2))
 274                 return s->version == DTLS1_2_VERSION;
 275             if (!(s->options & SSL_OP_NO_DTLSv1))
 276                 return s->version == DTLS1_VERSION;
 277         }
 278         return 0;               /* Unexpected state; fail closed. */
 279     case DTLS_CTRL_SET_LINK_MTU:
 280         if (larg < (long)dtls1_link_min_mtu())
 281             return 0;
 282         s->d1->link_mtu = larg;
 283         return 1;
 284     case DTLS_CTRL_GET_LINK_MIN_MTU:
 285         return (long)dtls1_link_min_mtu();
 286     case SSL_CTRL_SET_MTU:
 287         /*
 288          *  We may not have a BIO set yet so can't call dtls1_min_mtu()
 289          *  We'll have to make do with dtls1_link_min_mtu() and max overhead
 290          */
 291         if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD)
 292             return 0;
 293         s->d1->mtu = larg;
 294         return larg;
 295     default:
 296         ret = ssl3_ctrl(s, cmd, larg, parg);
 297         break;
 298     }
 299     return (ret);
 300 }
 301
 302 /*
 303  * As it's impossible to use stream ciphers in "datagram" mode, this
 304  * simple filter is designed to disengage them in DTLS. Unfortunately
 305  * there is no universal way to identify stream SSL_CIPHER, so we have
 306  * to explicitly list their SSL_* codes. Currently RC4 is the only one
 307  * available, but if new ones emerge, they will have to be added...
 308  */
 309 const SSL_CIPHER *dtls1_get_cipher(unsigned int u)
 310 {
 311     const SSL_CIPHER *ciph = ssl3_get_cipher(u);
 312
 313     if (ciph != NULL) {
 314         if (ciph->algorithm_enc == SSL_RC4)
 315             return NULL;
 316     }
 317
 318     return ciph;
 319 }
 320
 321 void dtls1_start_timer(SSL *s)
 322 {
 323 #ifndef OPENSSL_NO_SCTP
 324     /* Disable timer for SCTP */
 325     if (BIO_dgram_is_sctp(SSL_get_wbio(s))) {
 326         memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
 327         return;
 328     }
 329 #endif
 330
 331     /* If timer is not set, initialize duration with 1 second */
 332     if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
 333         s->d1->timeout_duration = 1;
 334     }
 335
 336     /* Set timeout to current time */
 337     get_current_time(&(s->d1->next_timeout));
 338
 339     /* Add duration to current time */
 340     s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
 341     BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
 342              &(s->d1->next_timeout));
 343 }
 344
 345 struct timeval *dtls1_get_timeout(SSL *s, struct timeval *timeleft)
 346 {
 347     struct timeval timenow;
 348
 349     /* If no timeout is set, just return NULL */
 350     if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
 351         return NULL;
 352     }
 353
 354     /* Get current time */
 355     get_current_time(&timenow);
 356
 357     /* If timer already expired, set remaining time to 0 */
 358     if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
 359         (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
 360          s->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
 361         memset(timeleft, 0, sizeof(*timeleft));
 362         return timeleft;
 363     }
 364
 365     /* Calculate time left until timer expires */
 366     memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
 367     timeleft->tv_sec -= timenow.tv_sec;
 368     timeleft->tv_usec -= timenow.tv_usec;
 369     if (timeleft->tv_usec < 0) {
 370         timeleft->tv_sec--;
 371         timeleft->tv_usec += 1000000;
 372     }
 373
 374     /*
 375      * If remaining time is less than 15 ms, set it to 0 to prevent issues
 376      * because of small devergences with socket timeouts.
 377      */
 378     if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) {
 379         memset(timeleft, 0, sizeof(*timeleft));
 380     }
 381
 382     return timeleft;
 383 }
 384
 385 int dtls1_is_timer_expired(SSL *s)
 386 {
 387     struct timeval timeleft;
 388
 389     /* Get time left until timeout, return false if no timer running */
 390     if (dtls1_get_timeout(s, &timeleft) == NULL) {
 391         return 0;
 392     }
 393
 394     /* Return false if timer is not expired yet */
 395     if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
 396         return 0;
 397     }
 398
 399     /* Timer expired, so return true */
 400     return 1;
 401 }
 402
 403 void dtls1_double_timeout(SSL *s)
 404 {
 405     s->d1->timeout_duration *= 2;
 406     if (s->d1->timeout_duration > 60)
 407         s->d1->timeout_duration = 60;
 408     dtls1_start_timer(s);
 409 }
 410
 411 void dtls1_stop_timer(SSL *s)
 412 {
 413     /* Reset everything */
 414     memset(&s->d1->timeout, 0, sizeof(s->d1->timeout));
 415     memset(&s->d1->next_timeout, 0, sizeof(s->d1->next_timeout));
 416     s->d1->timeout_duration = 1;
 417     BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
 418              &(s->d1->next_timeout));
 419     /* Clear retransmission buffer */
 420     dtls1_clear_record_buffer(s);
 421 }
 422
 423 int dtls1_check_timeout_num(SSL *s)
 424 {
 425     unsigned int mtu;
 426
 427     s->d1->timeout.num_alerts++;
 428
 429     /* Reduce MTU after 2 unsuccessful retransmissions */
 430     if (s->d1->timeout.num_alerts > 2
 431         && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
 432         mtu =
 433             BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0,
 434                      NULL);
 435         if (mtu < s->d1->mtu)
 436             s->d1->mtu = mtu;
 437     }
 438
 439     if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) {
 440         /* fail the connection, enough alerts have been sent */
 441         SSLerr(SSL_F_DTLS1_CHECK_TIMEOUT_NUM, SSL_R_READ_TIMEOUT_EXPIRED);
 442         return -1;
 443     }
 444
 445     return 0;
 446 }
 447
 448 int dtls1_handle_timeout(SSL *s)
 449 {
 450     /* if no timer is expired, don't do anything */
 451     if (!dtls1_is_timer_expired(s)) {
 452         return 0;
 453     }
 454
 455     dtls1_double_timeout(s);
 456
 457     if (dtls1_check_timeout_num(s) < 0)
 458         return -1;
 459
 460     s->d1->timeout.read_timeouts++;
 461     if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) {
 462         s->d1->timeout.read_timeouts = 1;
 463     }
 464 #ifndef OPENSSL_NO_HEARTBEATS
 465     if (s->tlsext_hb_pending) {
 466         s->tlsext_hb_pending = 0;
 467         return dtls1_heartbeat(s);
 468     }
 469 #endif
 470
 471     dtls1_start_timer(s);
 472     return dtls1_retransmit_buffered_messages(s);
 473 }
 474
 475 static void get_current_time(struct timeval *t)
 476 {
 477 #if defined(_WIN32)
 478     SYSTEMTIME st;
 479     union {
 480         unsigned __int64 ul;
 481         FILETIME ft;
 482     } now;
 483
 484     GetSystemTime(&st);
 485     SystemTimeToFileTime(&st, &now.ft);
 486 # ifdef  __MINGW32__
 487     now.ul -= 116444736000000000ULL;
 488 # else
 489     now.ul -= 116444736000000000UI64; /* re-bias to 1/1/1970 */
 490 # endif
 491     t->tv_sec = (long)(now.ul / 10000000);
 492     t->tv_usec = ((int)(now.ul % 10000000)) / 10;
 493 #elif defined(OPENSSL_SYS_VMS)
 494     struct timeb tb;
 495     ftime(&tb);
 496     t->tv_sec = (long)tb.time;
 497     t->tv_usec = (long)tb.millitm * 1000;
 498 #else
 499     gettimeofday(t, NULL);
 500 #endif
 501 }
 502
 503 int dtls1_listen(SSL *s, struct sockaddr *client)
 504 {
 505     int ret;
 506
 507     /* Ensure there is no state left over from a previous invocation */
 508     if (!SSL_clear(s))
 509         return -1;
 510
 511     SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
 512     s->d1->listen = 1;
 513
 514     ret = SSL_accept(s);
 515     if (ret <= 0)
 516         return ret;
 517
 518     (void)BIO_dgram_get_peer(SSL_get_rbio(s), client);
 519     return 1;
 520 }
 521
 522 static int dtls1_set_handshake_header(SSL *s, int htype, unsigned long len)
 523 {
 524     unsigned char *p = (unsigned char *)s->init_buf->data;
 525     dtls1_set_message_header(s, p, htype, len, 0, len);
 526     s->init_num = (int)len + DTLS1_HM_HEADER_LENGTH;
 527     s->init_off = 0;
 528     /* Buffer the message to handle re-xmits */
 529
 530     if (!dtls1_buffer_message(s, 0))
 531         return 0;
 532
 533     return 1;
 534 }
 535
 536 static int dtls1_handshake_write(SSL *s)
 537 {
 538     return dtls1_do_write(s, SSL3_RT_HANDSHAKE);
 539 }