lib/libssl/d1_lib.c

   1 /* $OpenBSD: d1_lib.c,v 1.42 2017/04/10 17:27:33 jsing 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 static int dtls1_listen(SSL *s, struct sockaddr *client);
  74
  75 SSL3_ENC_METHOD DTLSv1_enc_data = {
  76         .enc = dtls1_enc,
  77         .enc_flags = SSL_ENC_FLAG_EXPLICIT_IV,
  78 };
  79
  80 long
  81 dtls1_default_timeout(void)
  82 {
  83         /* 2 hours, the 24 hours mentioned in the DTLSv1 spec
  84          * is way too long for http, the cache would over fill */
  85         return (60*60*2);
  86 }
  87
  88 int
  89 dtls1_new(SSL *s)
  90 {
  91         DTLS1_STATE *d1;
  92
  93         if (!ssl3_new(s))
  94                 return (0);
  95         if ((d1 = calloc(1, sizeof(*d1))) == NULL) {
  96                 ssl3_free(s);
  97                 return (0);
  98         }
  99         if ((d1->internal = calloc(1, sizeof(*d1->internal))) == NULL) {
 100                 free(d1);
 101                 ssl3_free(s);
 102                 return (0);
 103         }
 104
 105         /* d1->handshake_epoch=0; */
 106
 107         d1->internal->unprocessed_rcds.q = pqueue_new();
 108         d1->internal->processed_rcds.q = pqueue_new();
 109         d1->internal->buffered_messages = pqueue_new();
 110         d1->sent_messages = pqueue_new();
 111         d1->internal->buffered_app_data.q = pqueue_new();
 112
 113         if (s->server) {
 114                 d1->internal->cookie_len = sizeof(D1I(s)->cookie);
 115         }
 116
 117         if (!d1->internal->unprocessed_rcds.q || !d1->internal->processed_rcds.q ||
 118             !d1->internal->buffered_messages || !d1->sent_messages ||
 119             !d1->internal->buffered_app_data.q) {
 120                 pqueue_free(d1->internal->unprocessed_rcds.q);
 121                 pqueue_free(d1->internal->processed_rcds.q);
 122                 pqueue_free(d1->internal->buffered_messages);
 123                 pqueue_free(d1->sent_messages);
 124                 pqueue_free(d1->internal->buffered_app_data.q);
 125                 free(d1);
 126                 ssl3_free(s);
 127                 return (0);
 128         }
 129
 130         s->d1 = d1;
 131         s->method->internal->ssl_clear(s);
 132         return (1);
 133 }
 134
 135 static void
 136 dtls1_clear_queues(SSL *s)
 137 {
 138         pitem *item = NULL;
 139         hm_fragment *frag = NULL;
 140         DTLS1_RECORD_DATA *rdata;
 141
 142         while ((item = pqueue_pop(D1I(s)->unprocessed_rcds.q)) != NULL) {
 143                 rdata = (DTLS1_RECORD_DATA *) item->data;
 144                 free(rdata->rbuf.buf);
 145                 free(item->data);
 146                 pitem_free(item);
 147         }
 148
 149         while ((item = pqueue_pop(D1I(s)->processed_rcds.q)) != NULL) {
 150                 rdata = (DTLS1_RECORD_DATA *) item->data;
 151                 free(rdata->rbuf.buf);
 152                 free(item->data);
 153                 pitem_free(item);
 154         }
 155
 156         while ((item = pqueue_pop(D1I(s)->buffered_messages)) != NULL) {
 157                 frag = (hm_fragment *)item->data;
 158                 free(frag->fragment);
 159                 free(frag);
 160                 pitem_free(item);
 161         }
 162
 163         while ((item = pqueue_pop(s->d1->sent_messages)) != NULL) {
 164                 frag = (hm_fragment *)item->data;
 165                 free(frag->fragment);
 166                 free(frag);
 167                 pitem_free(item);
 168         }
 169
 170         while ((item = pqueue_pop(D1I(s)->buffered_app_data.q)) != NULL) {
 171                 rdata = (DTLS1_RECORD_DATA *) item->data;
 172                 free(rdata->rbuf.buf);
 173                 free(item->data);
 174                 pitem_free(item);
 175         }
 176 }
 177
 178 void
 179 dtls1_free(SSL *s)
 180 {
 181         if (s == NULL)
 182                 return;
 183
 184         ssl3_free(s);
 185
 186         dtls1_clear_queues(s);
 187
 188         pqueue_free(D1I(s)->unprocessed_rcds.q);
 189         pqueue_free(D1I(s)->processed_rcds.q);
 190         pqueue_free(D1I(s)->buffered_messages);
 191         pqueue_free(s->d1->sent_messages);
 192         pqueue_free(D1I(s)->buffered_app_data.q);
 193
 194         freezero(s->d1->internal, sizeof(*s->d1->internal));
 195         freezero(s->d1, sizeof(*s->d1));
 196
 197         s->d1 = NULL;
 198 }
 199
 200 void
 201 dtls1_clear(SSL *s)
 202 {
 203         struct dtls1_state_internal_st *internal;
 204         pqueue unprocessed_rcds;
 205         pqueue processed_rcds;
 206         pqueue buffered_messages;
 207         pqueue sent_messages;
 208         pqueue buffered_app_data;
 209         unsigned int mtu;
 210
 211         if (s->d1) {
 212                 unprocessed_rcds = D1I(s)->unprocessed_rcds.q;
 213                 processed_rcds = D1I(s)->processed_rcds.q;
 214                 buffered_messages = D1I(s)->buffered_messages;
 215                 sent_messages = s->d1->sent_messages;
 216                 buffered_app_data = D1I(s)->buffered_app_data.q;
 217                 mtu = D1I(s)->mtu;
 218
 219                 dtls1_clear_queues(s);
 220
 221                 memset(s->d1->internal, 0, sizeof(*s->d1->internal));
 222                 internal = s->d1->internal;
 223                 memset(s->d1, 0, sizeof(*s->d1));
 224                 s->d1->internal = internal;
 225
 226                 if (s->server) {
 227                         D1I(s)->cookie_len = sizeof(D1I(s)->cookie);
 228                 }
 229
 230                 if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) {
 231                         D1I(s)->mtu = mtu;
 232                 }
 233
 234                 D1I(s)->unprocessed_rcds.q = unprocessed_rcds;
 235                 D1I(s)->processed_rcds.q = processed_rcds;
 236                 D1I(s)->buffered_messages = buffered_messages;
 237                 s->d1->sent_messages = sent_messages;
 238                 D1I(s)->buffered_app_data.q = buffered_app_data;
 239         }
 240
 241         ssl3_clear(s);
 242
 243         s->version = DTLS1_VERSION;
 244 }
 245
 246 long
 247 dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
 248 {
 249         int ret = 0;
 250
 251         switch (cmd) {
 252         case DTLS_CTRL_GET_TIMEOUT:
 253                 if (dtls1_get_timeout(s, (struct timeval*) parg) != NULL) {
 254                         ret = 1;
 255                 }
 256                 break;
 257         case DTLS_CTRL_HANDLE_TIMEOUT:
 258                 ret = dtls1_handle_timeout(s);
 259                 break;
 260         case DTLS_CTRL_LISTEN:
 261                 ret = dtls1_listen(s, parg);
 262                 break;
 263
 264         default:
 265                 ret = ssl3_ctrl(s, cmd, larg, parg);
 266                 break;
 267         }
 268         return (ret);
 269 }
 270
 271 /*
 272  * As it's impossible to use stream ciphers in "datagram" mode, this
 273  * simple filter is designed to disengage them in DTLS. Unfortunately
 274  * there is no universal way to identify stream SSL_CIPHER, so we have
 275  * to explicitly list their SSL_* codes. Currently RC4 is the only one
 276  * available, but if new ones emerge, they will have to be added...
 277  */
 278 const SSL_CIPHER *
 279 dtls1_get_cipher(unsigned int u)
 280 {
 281         const SSL_CIPHER *ciph = ssl3_get_cipher(u);
 282
 283         if (ciph != NULL) {
 284                 if (ciph->algorithm_enc == SSL_RC4)
 285                         return NULL;
 286         }
 287
 288         return ciph;
 289 }
 290
 291 void
 292 dtls1_start_timer(SSL *s)
 293 {
 294
 295         /* If timer is not set, initialize duration with 1 second */
 296         if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
 297                 s->d1->timeout_duration = 1;
 298         }
 299
 300         /* Set timeout to current time */
 301         gettimeofday(&(s->d1->next_timeout), NULL);
 302
 303         /* Add duration to current time */
 304         s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
 305         BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
 306             &s->d1->next_timeout);
 307 }
 308
 309 struct timeval*
 310 dtls1_get_timeout(SSL *s, struct timeval* timeleft)
 311 {
 312         struct timeval timenow;
 313
 314         /* If no timeout is set, just return NULL */
 315         if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
 316                 return NULL;
 317         }
 318
 319         /* Get current time */
 320         gettimeofday(&timenow, NULL);
 321
 322         /* If timer already expired, set remaining time to 0 */
 323         if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
 324             (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
 325              s->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
 326                 memset(timeleft, 0, sizeof(struct timeval));
 327                 return timeleft;
 328         }
 329
 330         /* Calculate time left until timer expires */
 331         memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
 332         timeleft->tv_sec -= timenow.tv_sec;
 333         timeleft->tv_usec -= timenow.tv_usec;
 334         if (timeleft->tv_usec < 0) {
 335                 timeleft->tv_sec--;
 336                 timeleft->tv_usec += 1000000;
 337         }
 338
 339         /* If remaining time is less than 15 ms, set it to 0
 340          * to prevent issues because of small devergences with
 341          * socket timeouts.
 342          */
 343         if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) {
 344                 memset(timeleft, 0, sizeof(struct timeval));
 345         }
 346
 347
 348         return timeleft;
 349 }
 350
 351 int
 352 dtls1_is_timer_expired(SSL *s)
 353 {
 354         struct timeval timeleft;
 355
 356         /* Get time left until timeout, return false if no timer running */
 357         if (dtls1_get_timeout(s, &timeleft) == NULL) {
 358                 return 0;
 359         }
 360
 361         /* Return false if timer is not expired yet */
 362         if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
 363                 return 0;
 364         }
 365
 366         /* Timer expired, so return true */
 367         return 1;
 368 }
 369
 370 void
 371 dtls1_double_timeout(SSL *s)
 372 {
 373         s->d1->timeout_duration *= 2;
 374         if (s->d1->timeout_duration > 60)
 375                 s->d1->timeout_duration = 60;
 376         dtls1_start_timer(s);
 377 }
 378
 379 void
 380 dtls1_stop_timer(SSL *s)
 381 {
 382         /* Reset everything */
 383         memset(&(D1I(s)->timeout), 0, sizeof(struct dtls1_timeout_st));
 384         memset(&(s->d1->next_timeout), 0, sizeof(struct timeval));
 385         s->d1->timeout_duration = 1;
 386         BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
 387             &(s->d1->next_timeout));
 388         /* Clear retransmission buffer */
 389         dtls1_clear_record_buffer(s);
 390 }
 391
 392 int
 393 dtls1_check_timeout_num(SSL *s)
 394 {
 395         D1I(s)->timeout.num_alerts++;
 396
 397         /* Reduce MTU after 2 unsuccessful retransmissions */
 398         if (D1I(s)->timeout.num_alerts > 2) {
 399                 D1I(s)->mtu = BIO_ctrl(SSL_get_wbio(s),
 400                     BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL);
 401
 402         }
 403
 404         if (D1I(s)->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) {
 405                 /* fail the connection, enough alerts have been sent */
 406                 SSLerror(s, SSL_R_READ_TIMEOUT_EXPIRED);
 407                 return -1;
 408         }
 409
 410         return 0;
 411 }
 412
 413 int
 414 dtls1_handle_timeout(SSL *s)
 415 {
 416         /* if no timer is expired, don't do anything */
 417         if (!dtls1_is_timer_expired(s)) {
 418                 return 0;
 419         }
 420
 421         dtls1_double_timeout(s);
 422
 423         if (dtls1_check_timeout_num(s) < 0)
 424                 return -1;
 425
 426         D1I(s)->timeout.read_timeouts++;
 427         if (D1I(s)->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) {
 428                 D1I(s)->timeout.read_timeouts = 1;
 429         }
 430
 431         dtls1_start_timer(s);
 432         return dtls1_retransmit_buffered_messages(s);
 433 }
 434
 435 int
 436 dtls1_listen(SSL *s, struct sockaddr *client)
 437 {
 438         int ret;
 439
 440         /* Ensure there is no state left over from a previous invocation */
 441         SSL_clear(s);
 442
 443         SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
 444         D1I(s)->listen = 1;
 445
 446         ret = SSL_accept(s);
 447         if (ret <= 0)
 448                 return ret;
 449
 450         (void)BIO_dgram_get_peer(SSL_get_rbio(s), client);
 451         return 1;
 452 }
 453
 454 void
 455 dtls1_build_sequence_number(unsigned char *dst, unsigned char *seq,
 456     unsigned short epoch)
 457 {
 458         unsigned char dtlsseq[SSL3_SEQUENCE_SIZE];
 459         unsigned char *p;
 460
 461         p = dtlsseq;
 462         s2n(epoch, p);
 463         memcpy(p, &seq[2], SSL3_SEQUENCE_SIZE - 2);
 464         memcpy(dst, dtlsseq, SSL3_SEQUENCE_SIZE);
 465 }