crypto/libressl/ssl/d1_lib.c

   1 /* $OpenBSD: d1_lib.c,v 1.61 2021/10/23 13:36:03 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 "dtls_locl.h"
  71 #include "pqueue.h"
  72 #include "ssl_locl.h"
  73
  74 void dtls1_hm_fragment_free(hm_fragment *frag);
  75
  76 static int dtls1_listen(SSL *s, struct sockaddr *client);
  77
  78 int
  79 dtls1_new(SSL *s)
  80 {
  81         if (!ssl3_new(s))
  82                 goto err;
  83
  84         if ((s->d1 = calloc(1, sizeof(*s->d1))) == NULL)
  85                 goto err;
  86
  87         if ((s->d1->unprocessed_rcds.q = pqueue_new()) == NULL)
  88                 goto err;
  89         if ((s->d1->buffered_messages = pqueue_new()) == NULL)
  90                 goto err;
  91         if ((s->d1->sent_messages = pqueue_new()) == NULL)
  92                 goto err;
  93         if ((s->d1->buffered_app_data.q = pqueue_new()) == NULL)
  94                 goto err;
  95
  96         if (s->server)
  97                 s->d1->cookie_len = sizeof(s->d1->cookie);
  98
  99         s->method->ssl_clear(s);
 100         return (1);
 101
 102  err:
 103         dtls1_free(s);
 104         return (0);
 105 }
 106
 107 static void
 108 dtls1_drain_records(pqueue queue)
 109 {
 110         pitem *item;
 111         DTLS1_RECORD_DATA_INTERNAL *rdata;
 112
 113         if (queue == NULL)
 114                 return;
 115
 116         while ((item = pqueue_pop(queue)) != NULL) {
 117                 rdata = (DTLS1_RECORD_DATA_INTERNAL *)item->data;
 118                 ssl3_release_buffer(&rdata->rbuf);
 119                 free(item->data);
 120                 pitem_free(item);
 121         }
 122 }
 123
 124 static void
 125 dtls1_drain_fragments(pqueue queue)
 126 {
 127         pitem *item;
 128
 129         if (queue == NULL)
 130                 return;
 131
 132         while ((item = pqueue_pop(queue)) != NULL) {
 133                 dtls1_hm_fragment_free(item->data);
 134                 pitem_free(item);
 135         }
 136 }
 137
 138 static void
 139 dtls1_clear_queues(SSL *s)
 140 {
 141         dtls1_drain_records(s->d1->unprocessed_rcds.q);
 142         dtls1_drain_fragments(s->d1->buffered_messages);
 143         dtls1_drain_fragments(s->d1->sent_messages);
 144         dtls1_drain_records(s->d1->buffered_app_data.q);
 145 }
 146
 147 void
 148 dtls1_free(SSL *s)
 149 {
 150         if (s == NULL)
 151                 return;
 152
 153         ssl3_free(s);
 154
 155         if (s->d1 == NULL)
 156                 return;
 157
 158         dtls1_clear_queues(s);
 159
 160         pqueue_free(s->d1->unprocessed_rcds.q);
 161         pqueue_free(s->d1->buffered_messages);
 162         pqueue_free(s->d1->sent_messages);
 163         pqueue_free(s->d1->buffered_app_data.q);
 164
 165         freezero(s->d1, sizeof(*s->d1));
 166         s->d1 = NULL;
 167 }
 168
 169 void
 170 dtls1_clear(SSL *s)
 171 {
 172         pqueue unprocessed_rcds;
 173         pqueue buffered_messages;
 174         pqueue sent_messages;
 175         pqueue buffered_app_data;
 176         unsigned int mtu;
 177
 178         if (s->d1) {
 179                 unprocessed_rcds = s->d1->unprocessed_rcds.q;
 180                 buffered_messages = s->d1->buffered_messages;
 181                 sent_messages = s->d1->sent_messages;
 182                 buffered_app_data = s->d1->buffered_app_data.q;
 183                 mtu = s->d1->mtu;
 184
 185                 dtls1_clear_queues(s);
 186
 187                 memset(s->d1, 0, sizeof(*s->d1));
 188
 189                 s->d1->unprocessed_rcds.epoch =
 190                     tls12_record_layer_read_epoch(s->internal->rl) + 1;
 191
 192                 if (s->server) {
 193                         s->d1->cookie_len = sizeof(s->d1->cookie);
 194                 }
 195
 196                 if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU) {
 197                         s->d1->mtu = mtu;
 198                 }
 199
 200                 s->d1->unprocessed_rcds.q = unprocessed_rcds;
 201                 s->d1->buffered_messages = buffered_messages;
 202                 s->d1->sent_messages = sent_messages;
 203                 s->d1->buffered_app_data.q = buffered_app_data;
 204         }
 205
 206         ssl3_clear(s);
 207
 208         s->version = DTLS1_VERSION;
 209 }
 210
 211 long
 212 dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
 213 {
 214         int ret = 0;
 215
 216         switch (cmd) {
 217         case DTLS_CTRL_GET_TIMEOUT:
 218                 if (dtls1_get_timeout(s, (struct timeval*) parg) != NULL) {
 219                         ret = 1;
 220                 }
 221                 break;
 222         case DTLS_CTRL_HANDLE_TIMEOUT:
 223                 ret = dtls1_handle_timeout(s);
 224                 break;
 225         case DTLS_CTRL_LISTEN:
 226                 ret = dtls1_listen(s, parg);
 227                 break;
 228
 229         default:
 230                 ret = ssl3_ctrl(s, cmd, larg, parg);
 231                 break;
 232         }
 233         return (ret);
 234 }
 235
 236 /*
 237  * As it's impossible to use stream ciphers in "datagram" mode, this
 238  * simple filter is designed to disengage them in DTLS. Unfortunately
 239  * there is no universal way to identify stream SSL_CIPHER, so we have
 240  * to explicitly list their SSL_* codes. Currently RC4 is the only one
 241  * available, but if new ones emerge, they will have to be added...
 242  */
 243 const SSL_CIPHER *
 244 dtls1_get_cipher(unsigned int u)
 245 {
 246         const SSL_CIPHER *cipher;
 247
 248         if ((cipher = ssl3_get_cipher(u)) == NULL)
 249                 return NULL;
 250
 251         if (cipher->algorithm_enc == SSL_RC4)
 252                 return NULL;
 253
 254         return cipher;
 255 }
 256
 257 void
 258 dtls1_start_timer(SSL *s)
 259 {
 260
 261         /* If timer is not set, initialize duration with 1 second */
 262         if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
 263                 s->d1->timeout_duration = 1;
 264         }
 265
 266         /* Set timeout to current time */
 267         gettimeofday(&(s->d1->next_timeout), NULL);
 268
 269         /* Add duration to current time */
 270         s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
 271         BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
 272             &s->d1->next_timeout);
 273 }
 274
 275 struct timeval*
 276 dtls1_get_timeout(SSL *s, struct timeval* timeleft)
 277 {
 278         struct timeval timenow;
 279
 280         /* If no timeout is set, just return NULL */
 281         if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0) {
 282                 return NULL;
 283         }
 284
 285         /* Get current time */
 286         gettimeofday(&timenow, NULL);
 287
 288         /* If timer already expired, set remaining time to 0 */
 289         if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
 290             (s->d1->next_timeout.tv_sec == timenow.tv_sec &&
 291              s->d1->next_timeout.tv_usec <= timenow.tv_usec)) {
 292                 memset(timeleft, 0, sizeof(struct timeval));
 293                 return timeleft;
 294         }
 295
 296         /* Calculate time left until timer expires */
 297         memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
 298         timeleft->tv_sec -= timenow.tv_sec;
 299         timeleft->tv_usec -= timenow.tv_usec;
 300         if (timeleft->tv_usec < 0) {
 301                 timeleft->tv_sec--;
 302                 timeleft->tv_usec += 1000000;
 303         }
 304
 305         /* If remaining time is less than 15 ms, set it to 0
 306          * to prevent issues because of small devergences with
 307          * socket timeouts.
 308          */
 309         if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000) {
 310                 memset(timeleft, 0, sizeof(struct timeval));
 311         }
 312
 313
 314         return timeleft;
 315 }
 316
 317 int
 318 dtls1_is_timer_expired(SSL *s)
 319 {
 320         struct timeval timeleft;
 321
 322         /* Get time left until timeout, return false if no timer running */
 323         if (dtls1_get_timeout(s, &timeleft) == NULL) {
 324                 return 0;
 325         }
 326
 327         /* Return false if timer is not expired yet */
 328         if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0) {
 329                 return 0;
 330         }
 331
 332         /* Timer expired, so return true */
 333         return 1;
 334 }
 335
 336 void
 337 dtls1_double_timeout(SSL *s)
 338 {
 339         s->d1->timeout_duration *= 2;
 340         if (s->d1->timeout_duration > 60)
 341                 s->d1->timeout_duration = 60;
 342         dtls1_start_timer(s);
 343 }
 344
 345 void
 346 dtls1_stop_timer(SSL *s)
 347 {
 348         /* Reset everything */
 349         memset(&(s->d1->timeout), 0, sizeof(struct dtls1_timeout_st));
 350         memset(&(s->d1->next_timeout), 0, sizeof(struct timeval));
 351         s->d1->timeout_duration = 1;
 352         BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0,
 353             &(s->d1->next_timeout));
 354         /* Clear retransmission buffer */
 355         dtls1_clear_record_buffer(s);
 356 }
 357
 358 int
 359 dtls1_check_timeout_num(SSL *s)
 360 {
 361         s->d1->timeout.num_alerts++;
 362
 363         /* Reduce MTU after 2 unsuccessful retransmissions */
 364         if (s->d1->timeout.num_alerts > 2) {
 365                 s->d1->mtu = BIO_ctrl(SSL_get_wbio(s),
 366                     BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL);
 367
 368         }
 369
 370         if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT) {
 371                 /* fail the connection, enough alerts have been sent */
 372                 SSLerror(s, SSL_R_READ_TIMEOUT_EXPIRED);
 373                 return -1;
 374         }
 375
 376         return 0;
 377 }
 378
 379 int
 380 dtls1_handle_timeout(SSL *s)
 381 {
 382         /* if no timer is expired, don't do anything */
 383         if (!dtls1_is_timer_expired(s)) {
 384                 return 0;
 385         }
 386
 387         dtls1_double_timeout(s);
 388
 389         if (dtls1_check_timeout_num(s) < 0)
 390                 return -1;
 391
 392         s->d1->timeout.read_timeouts++;
 393         if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT) {
 394                 s->d1->timeout.read_timeouts = 1;
 395         }
 396
 397         dtls1_start_timer(s);
 398         return dtls1_retransmit_buffered_messages(s);
 399 }
 400
 401 int
 402 dtls1_listen(SSL *s, struct sockaddr *client)
 403 {
 404         int ret;
 405
 406         /* Ensure there is no state left over from a previous invocation */
 407         SSL_clear(s);
 408
 409         SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
 410         s->d1->listen = 1;
 411
 412         ret = SSL_accept(s);
 413         if (ret <= 0)
 414                 return ret;
 415
 416         (void)BIO_dgram_get_peer(SSL_get_rbio(s), client);
 417         return 1;
 418 }