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_WIN32) || defined(OPENSSL_SYS_VMS)
  66 #include <sys/timeb.h>
  67 #endif
  68
  69 static void get_current_time(struct timeval *t);
  70 const char dtls1_version_str[]="DTLSv1" OPENSSL_VERSION_PTEXT;
  71 int dtls1_listen(SSL *s, struct sockaddr *client);
  72
  73 SSL3_ENC_METHOD DTLSv1_enc_data={
  74     dtls1_enc,
  75         tls1_mac,
  76         tls1_setup_key_block,
  77         tls1_generate_master_secret,
  78         tls1_change_cipher_state,
  79         tls1_final_finish_mac,
  80         TLS1_FINISH_MAC_LENGTH,
  81         tls1_cert_verify_mac,
  82         TLS_MD_CLIENT_FINISH_CONST,TLS_MD_CLIENT_FINISH_CONST_SIZE,
  83         TLS_MD_SERVER_FINISH_CONST,TLS_MD_SERVER_FINISH_CONST_SIZE,
  84         tls1_alert_code,
  85         };
  86
  87 long dtls1_default_timeout(void)
  88         {
  89         /* 2 hours, the 24 hours mentioned in the DTLSv1 spec
  90          * is way too long for http, the cache would over fill */
  91         return(60*60*2);
  92         }
  93
  94 int dtls1_new(SSL *s)
  95         {
  96         DTLS1_STATE *d1;
  97
  98         if (!ssl3_new(s)) return(0);
  99         if ((d1=OPENSSL_malloc(sizeof *d1)) == NULL) return (0);
 100         memset(d1,0, sizeof *d1);
 101
 102         /* d1->handshake_epoch=0; */
 103
 104         d1->unprocessed_rcds.q=pqueue_new();
 105         d1->processed_rcds.q=pqueue_new();
 106         d1->buffered_messages = pqueue_new();
 107         d1->sent_messages=pqueue_new();
 108         d1->buffered_app_data.q=pqueue_new();
 109
 110         if ( s->server)
 111                 {
 112                 d1->cookie_len = sizeof(s->d1->cookie);
 113                 }
 114
 115         d1->link_mtu = 0;
 116         d1->mtu = 0;
 117
 118         if( ! d1->unprocessed_rcds.q || ! d1->processed_rcds.q
 119         || ! d1->buffered_messages || ! d1->sent_messages || ! d1->buffered_app_data.q)
 120                 {
 121         if ( d1->unprocessed_rcds.q) pqueue_free(d1->unprocessed_rcds.q);
 122         if ( d1->processed_rcds.q) pqueue_free(d1->processed_rcds.q);
 123         if ( d1->buffered_messages) pqueue_free(d1->buffered_messages);
 124                 if ( d1->sent_messages) pqueue_free(d1->sent_messages);
 125                 if ( d1->buffered_app_data.q) pqueue_free(d1->buffered_app_data.q);
 126                 OPENSSL_free(d1);
 127                 return (0);
 128                 }
 129
 130         s->d1=d1;
 131         s->method->ssl_clear(s);
 132         return(1);
 133         }
 134
 135 static void dtls1_clear_queues(SSL *s)
 136         {
 137     pitem *item = NULL;
 138     hm_fragment *frag = NULL;
 139         DTLS1_RECORD_DATA *rdata;
 140
 141     while( (item = pqueue_pop(s->d1->unprocessed_rcds.q)) != NULL)
 142         {
 143                 rdata = (DTLS1_RECORD_DATA *) item->data;
 144                 if (rdata->rbuf.buf)
 145                         {
 146                         OPENSSL_free(rdata->rbuf.buf);
 147                         }
 148         OPENSSL_free(item->data);
 149         pitem_free(item);
 150         }
 151
 152     while( (item = pqueue_pop(s->d1->processed_rcds.q)) != NULL)
 153         {
 154                 rdata = (DTLS1_RECORD_DATA *) item->data;
 155                 if (rdata->rbuf.buf)
 156                         {
 157                         OPENSSL_free(rdata->rbuf.buf);
 158                         }
 159         OPENSSL_free(item->data);
 160         pitem_free(item);
 161         }
 162
 163     while( (item = pqueue_pop(s->d1->buffered_messages)) != NULL)
 164         {
 165         frag = (hm_fragment *)item->data;
 166         dtls1_hm_fragment_free(frag);
 167         pitem_free(item);
 168         }
 169
 170     while ( (item = pqueue_pop(s->d1->sent_messages)) != NULL)
 171         {
 172         frag = (hm_fragment *)item->data;
 173         dtls1_hm_fragment_free(frag);
 174         pitem_free(item);
 175         }
 176
 177         while ( (item = pqueue_pop(s->d1->buffered_app_data.q)) != NULL)
 178                 {
 179                 rdata = (DTLS1_RECORD_DATA *) item->data;
 180                 if (rdata->rbuf.buf)
 181                         {
 182                         OPENSSL_free(rdata->rbuf.buf);
 183                         }
 184                 OPENSSL_free(item->data);
 185                 pitem_free(item);
 186                 }
 187         }
 188
 189 void dtls1_free(SSL *s)
 190         {
 191         ssl3_free(s);
 192
 193         dtls1_clear_queues(s);
 194
 195     pqueue_free(s->d1->unprocessed_rcds.q);
 196     pqueue_free(s->d1->processed_rcds.q);
 197     pqueue_free(s->d1->buffered_messages);
 198         pqueue_free(s->d1->sent_messages);
 199         pqueue_free(s->d1->buffered_app_data.q);
 200
 201         OPENSSL_free(s->d1);
 202         s->d1 = NULL;
 203         }
 204
 205 void dtls1_clear(SSL *s)
 206         {
 207     pqueue unprocessed_rcds;
 208     pqueue processed_rcds;
 209     pqueue buffered_messages;
 210         pqueue sent_messages;
 211         pqueue buffered_app_data;
 212         unsigned int mtu;
 213         unsigned int link_mtu;
 214
 215         if (s->d1)
 216                 {
 217                 unprocessed_rcds = s->d1->unprocessed_rcds.q;
 218                 processed_rcds = s->d1->processed_rcds.q;
 219                 buffered_messages = s->d1->buffered_messages;
 220                 sent_messages = s->d1->sent_messages;
 221                 buffered_app_data = s->d1->buffered_app_data.q;
 222                 mtu = s->d1->mtu;
 223                 link_mtu = s->d1->link_mtu;
 224
 225                 dtls1_clear_queues(s);
 226
 227                 memset(s->d1, 0, sizeof(*(s->d1)));
 228
 229                 if (s->server)
 230                         {
 231                         s->d1->cookie_len = sizeof(s->d1->cookie);
 232                         }
 233
 234                 if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)
 235                         {
 236                         s->d1->mtu = mtu;
 237                         s->d1->link_mtu = link_mtu;
 238                         }
 239
 240                 s->d1->unprocessed_rcds.q = unprocessed_rcds;
 241                 s->d1->processed_rcds.q = processed_rcds;
 242                 s->d1->buffered_messages = buffered_messages;
 243                 s->d1->sent_messages = sent_messages;
 244                 s->d1->buffered_app_data.q = buffered_app_data;
 245                 }
 246
 247         ssl3_clear(s);
 248         if (s->options & SSL_OP_CISCO_ANYCONNECT)
 249                 s->version=DTLS1_BAD_VER;
 250         else
 251                 s->version=DTLS1_VERSION;
 252         }
 253
 254 long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
 255         {
 256         int ret=0;
 257
 258         switch (cmd)
 259                 {
 260         case DTLS_CTRL_GET_TIMEOUT:
 261                 if (dtls1_get_timeout(s, (struct timeval*) parg) != NULL)
 262                         {
 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         case SSL_CTRL_CHECK_PROTO_VERSION:
 273                 /* For library-internal use; checks that the current protocol
 274                  * is the highest enabled version (according to s->ctx->method,
 275                  * as version negotiation may have changed s->method). */
 276 #if DTLS_MAX_VERSION != DTLS1_VERSION
 277 #  error Code needs update for DTLS_method() support beyond DTLS1_VERSION.
 278 #endif
 279                 /* Just one protocol version is supported so far;
 280                  * fail closed if the version is not as expected. */
 281                 return s->version == DTLS_MAX_VERSION;
 282
 283                 /* Just one protocol version is supported so far;
 284                  * fail closed if the version is not as expected. */
 285                 return s->version == DTLS_MAX_VERSION;
 286         case DTLS_CTRL_SET_LINK_MTU:
 287                 if (larg < (long)dtls1_link_min_mtu())
 288                         return 0;
 289                 s->d1->link_mtu = larg;
 290                 return 1;
 291         case DTLS_CTRL_GET_LINK_MIN_MTU:
 292                 return (long)dtls1_link_min_mtu();
 293         case SSL_CTRL_SET_MTU:
 294                 /*
 295                  *  We may not have a BIO set yet so can't call dtls1_min_mtu()
 296                  *  We'll have to make do with dtls1_link_min_mtu() and max overhead
 297                  */
 298                 if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD)
 299                         return 0;
 300                 s->d1->mtu = larg;
 301                 return larg;
 302         default:
 303                 ret = ssl3_ctrl(s, cmd, larg, parg);
 304                 break;
 305                 }
 306         return(ret);
 307         }
 308
 309 /*
 310  * As it's impossible to use stream ciphers in "datagram" mode, this
 311  * simple filter is designed to disengage them in DTLS. Unfortunately
 312  * there is no universal way to identify stream SSL_CIPHER, so we have
 313  * to explicitly list their SSL_* codes. Currently RC4 is the only one
 314  * available, but if new ones emerge, they will have to be added...
 315  */
 316 const SSL_CIPHER *dtls1_get_cipher(unsigned int u)
 317         {
 318         const SSL_CIPHER *ciph = ssl3_get_cipher(u);
 319
 320         if (ciph != NULL)
 321                 {
 322                 if (ciph->algorithm_enc == SSL_RC4)
 323                         return NULL;
 324                 }
 325
 326         return ciph;
 327         }
 328
 329 void dtls1_start_timer(SSL *s)
 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                 {
 334                 s->d1->timeout_duration = 1;
 335                 }
 336
 337         /* Set timeout to current time */
 338         get_current_time(&(s->d1->next_timeout));
 339
 340         /* Add duration to current time */
 341         s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
 342         BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, &(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                 {
 352                 return NULL;
 353                 }
 354
 355         /* Get current time */
 356         get_current_time(&timenow);
 357
 358         /* If timer already expired, set remaining time to 0 */
 359         if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
 360                 (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
 361                  s->d1->next_timeout.tv_usec <= timenow.tv_usec))
 362                 {
 363                 memset(timeleft, 0, sizeof(struct timeval));
 364                 return timeleft;
 365                 }
 366
 367         /* Calculate time left until timer expires */
 368         memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
 369         timeleft->tv_sec -= timenow.tv_sec;
 370         timeleft->tv_usec -= timenow.tv_usec;
 371         if (timeleft->tv_usec < 0)
 372                 {
 373                 timeleft->tv_sec--;
 374                 timeleft->tv_usec += 1000000;
 375                 }
 376
 377         /* If remaining time is less than 15 ms, set it to 0
 378          * to prevent issues because of small devergences with
 379          * socket timeouts.
 380          */
 381         if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000)
 382                 {
 383                 memset(timeleft, 0, sizeof(struct timeval));
 384                 }
 385
 386
 387         return timeleft;
 388         }
 389
 390 int dtls1_is_timer_expired(SSL *s)
 391         {
 392         struct timeval timeleft;
 393
 394         /* Get time left until timeout, return false if no timer running */
 395         if (dtls1_get_timeout(s, &timeleft) == NULL)
 396                 {
 397                 return 0;
 398                 }
 399
 400         /* Return false if timer is not expired yet */
 401         if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0)
 402                 {
 403                 return 0;
 404                 }
 405
 406         /* Timer expired, so return true */
 407         return 1;
 408         }
 409
 410 void dtls1_double_timeout(SSL *s)
 411         {
 412         s->d1->timeout_duration *= 2;
 413         if (s->d1->timeout_duration > 60)
 414                 s->d1->timeout_duration = 60;
 415         dtls1_start_timer(s);
 416         }
 417
 418 void dtls1_stop_timer(SSL *s)
 419         {
 420         /* Reset everything */
 421         memset(&(s->d1->timeout), 0, sizeof(struct dtls1_timeout_st));
 422         memset(&(s->d1->next_timeout), 0, sizeof(struct timeval));
 423         s->d1->timeout_duration = 1;
 424         BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, &(s->d1->next_timeout));
 425         /* Clear retransmission buffer */
 426         dtls1_clear_record_buffer(s);
 427         }
 428
 429 int dtls1_check_timeout_num(SSL *s)
 430         {
 431         unsigned int mtu;
 432
 433         s->d1->timeout.num_alerts++;
 434
 435         /* Reduce MTU after 2 unsuccessful retransmissions */
 436         if (s->d1->timeout.num_alerts > 2
 437                         && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))
 438                 {
 439                 mtu = BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL);
 440                 if(mtu < s->d1->mtu)
 441                         s->d1->mtu = mtu;
 442                 }
 443
 444         if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT)
 445                 {
 446                 /* fail the connection, enough alerts have been sent */
 447                 SSLerr(SSL_F_DTLS1_CHECK_TIMEOUT_NUM,SSL_R_READ_TIMEOUT_EXPIRED);
 448                 return -1;
 449                 }
 450
 451         return 0;
 452         }
 453
 454 int dtls1_handle_timeout(SSL *s)
 455         {
 456         /* if no timer is expired, don't do anything */
 457         if (!dtls1_is_timer_expired(s))
 458                 {
 459                 return 0;
 460                 }
 461
 462         dtls1_double_timeout(s);
 463
 464         if (dtls1_check_timeout_num(s) < 0)
 465                 return -1;
 466
 467         s->d1->timeout.read_timeouts++;
 468         if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT)
 469                 {
 470                 s->d1->timeout.read_timeouts = 1;
 471                 }
 472
 473         dtls1_start_timer(s);
 474         return dtls1_retransmit_buffered_messages(s);
 475         }
 476
 477 static void get_current_time(struct timeval *t)
 478 {
 479 #ifdef OPENSSL_SYS_WIN32
 480         struct _timeb tb;
 481         _ftime(&tb);
 482         t->tv_sec = (long)tb.time;
 483         t->tv_usec = (long)tb.millitm * 1000;
 484 #elif defined(OPENSSL_SYS_VMS)
 485         struct timeb tb;
 486         ftime(&tb);
 487         t->tv_sec = (long)tb.time;
 488         t->tv_usec = (long)tb.millitm * 1000;
 489 #else
 490         gettimeofday(t, NULL);
 491 #endif
 492 }
 493
 494 int dtls1_listen(SSL *s, struct sockaddr *client)
 495         {
 496         int ret;
 497
 498         SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
 499         s->d1->listen = 1;
 500
 501         ret = SSL_accept(s);
 502         if (ret <= 0) return ret;
 503
 504         (void) BIO_dgram_get_peer(SSL_get_rbio(s), client);
 505         return 1;
 506         }