ssl/d1_both.c

   1 /* ssl/d1_both.c */
   2 /*
   3  * DTLS implementation written by Nagendra Modadugu
   4  * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
   5  */
   6 /* ====================================================================
   7  * Copyright (c) 1998-2005 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 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  60  * All rights reserved.
  61  *
  62  * This package is an SSL implementation written
  63  * by Eric Young (eay@cryptsoft.com).
  64  * The implementation was written so as to conform with Netscapes SSL.
  65  *
  66  * This library is free for commercial and non-commercial use as long as
  67  * the following conditions are aheared to.  The following conditions
  68  * apply to all code found in this distribution, be it the RC4, RSA,
  69  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  70  * included with this distribution is covered by the same copyright terms
  71  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  72  *
  73  * Copyright remains Eric Young's, and as such any Copyright notices in
  74  * the code are not to be removed.
  75  * If this package is used in a product, Eric Young should be given attribution
  76  * as the author of the parts of the library used.
  77  * This can be in the form of a textual message at program startup or
  78  * in documentation (online or textual) provided with the package.
  79  *
  80  * Redistribution and use in source and binary forms, with or without
  81  * modification, are permitted provided that the following conditions
  82  * are met:
  83  * 1. Redistributions of source code must retain the copyright
  84  *    notice, this list of conditions and the following disclaimer.
  85  * 2. Redistributions in binary form must reproduce the above copyright
  86  *    notice, this list of conditions and the following disclaimer in the
  87  *    documentation and/or other materials provided with the distribution.
  88  * 3. All advertising materials mentioning features or use of this software
  89  *    must display the following acknowledgement:
  90  *    "This product includes cryptographic software written by
  91  *     Eric Young (eay@cryptsoft.com)"
  92  *    The word 'cryptographic' can be left out if the rouines from the library
  93  *    being used are not cryptographic related :-).
  94  * 4. If you include any Windows specific code (or a derivative thereof) from
  95  *    the apps directory (application code) you must include an acknowledgement:
  96  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  97  *
  98  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  99  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 100  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 101  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 102  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 103  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 104  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 105  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 106  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 107  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 108  * SUCH DAMAGE.
 109  *
 110  * The licence and distribution terms for any publically available version or
 111  * derivative of this code cannot be changed.  i.e. this code cannot simply be
 112  * copied and put under another distribution licence
 113  * [including the GNU Public Licence.]
 114  */
 115
 116 #include <limits.h>
 117 #include <string.h>
 118 #include <stdio.h>
 119 #include "ssl_locl.h"
 120 #include <openssl/buffer.h>
 121 #include <openssl/rand.h>
 122 #include <openssl/objects.h>
 123 #include <openssl/evp.h>
 124 #include <openssl/x509.h>
 125
 126 #define RSMBLY_BITMASK_SIZE(msg_len) (((msg_len) + 7) / 8)
 127
 128 #define RSMBLY_BITMASK_MARK(bitmask, start, end) { \
 129                         if ((end) - (start) <= 8) { \
 130                                 long ii; \
 131                                 for (ii = (start); ii < (end); ii++) bitmask[((ii) >> 3)] |= (1 << ((ii) & 7)); \
 132                         } else { \
 133                                 long ii; \
 134                                 bitmask[((start) >> 3)] |= bitmask_start_values[((start) & 7)]; \
 135                                 for (ii = (((start) >> 3) + 1); ii < ((((end) - 1)) >> 3); ii++) bitmask[ii] = 0xff; \
 136                                 bitmask[(((end) - 1) >> 3)] |= bitmask_end_values[((end) & 7)]; \
 137                         } }
 138
 139 #define RSMBLY_BITMASK_IS_COMPLETE(bitmask, msg_len, is_complete) { \
 140                         long ii; \
 141                         OPENSSL_assert((msg_len) > 0); \
 142                         is_complete = 1; \
 143                         if (bitmask[(((msg_len) - 1) >> 3)] != bitmask_end_values[((msg_len) & 7)]) is_complete = 0; \
 144                         if (is_complete) for (ii = (((msg_len) - 1) >> 3) - 1; ii >= 0 ; ii--) \
 145                                 if (bitmask[ii] != 0xff) { is_complete = 0; break; } }
 146
 147 #if 0
 148 #define RSMBLY_BITMASK_PRINT(bitmask, msg_len) { \
 149                         long ii; \
 150                         printf("bitmask: "); for (ii = 0; ii < (msg_len); ii++) \
 151                         printf("%d ", (bitmask[ii >> 3] & (1 << (ii & 7))) >> (ii & 7)); \
 152                         printf("\n"); }
 153 #endif
 154
 155 static unsigned char bitmask_start_values[] = {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80};
 156 static unsigned char bitmask_end_values[]   = {0xff, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f};
 157
 158 /* XDTLS:  figure out the right values */
 159 static const unsigned int g_probable_mtu[] = {1500 - 28, 512 - 28, 256 - 28};
 160
 161 static unsigned int dtls1_guess_mtu(unsigned int curr_mtu);
 162 static void dtls1_fix_message_header(SSL *s, unsigned long frag_off,
 163         unsigned long frag_len);
 164 static unsigned char *dtls1_write_message_header(SSL *s,
 165         unsigned char *p);
 166 static void dtls1_set_message_header_int(SSL *s, unsigned char mt,
 167         unsigned long len, unsigned short seq_num, unsigned long frag_off,
 168         unsigned long frag_len);
 169 static long dtls1_get_message_fragment(SSL *s, int st1, int stn,
 170         long max, int *ok);
 171
 172 static hm_fragment *
 173 dtls1_hm_fragment_new(unsigned long frag_len, int reassembly)
 174         {
 175         hm_fragment *frag = NULL;
 176         unsigned char *buf = NULL;
 177         unsigned char *bitmask = NULL;
 178
 179         frag = (hm_fragment *)OPENSSL_malloc(sizeof(hm_fragment));
 180         if ( frag == NULL)
 181                 return NULL;
 182
 183         if (frag_len)
 184                 {
 185                 buf = (unsigned char *)OPENSSL_malloc(frag_len);
 186                 if ( buf == NULL)
 187                         {
 188                         OPENSSL_free(frag);
 189                         return NULL;
 190                         }
 191                 }
 192
 193         /* zero length fragment gets zero frag->fragment */
 194         frag->fragment = buf;
 195
 196         /* Initialize reassembly bitmask if necessary */
 197         if (reassembly)
 198                 {
 199                 bitmask = (unsigned char *)OPENSSL_malloc(RSMBLY_BITMASK_SIZE(frag_len));
 200                 if (bitmask == NULL)
 201                         {
 202                         if (buf != NULL) OPENSSL_free(buf);
 203                         OPENSSL_free(frag);
 204                         return NULL;
 205                         }
 206                 memset(bitmask, 0, RSMBLY_BITMASK_SIZE(frag_len));
 207                 }
 208
 209         frag->reassembly = bitmask;
 210
 211         return frag;
 212         }
 213
 214 static void
 215 dtls1_hm_fragment_free(hm_fragment *frag)
 216         {
 217
 218         if (frag->msg_header.is_ccs)
 219                 {
 220                 EVP_CIPHER_CTX_free(frag->msg_header.saved_retransmit_state.enc_write_ctx);
 221                 EVP_MD_CTX_destroy(frag->msg_header.saved_retransmit_state.write_hash);
 222                 }
 223         if (frag->fragment) OPENSSL_free(frag->fragment);
 224         if (frag->reassembly) OPENSSL_free(frag->reassembly);
 225         OPENSSL_free(frag);
 226         }
 227
 228 /* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */
 229 int dtls1_do_write(SSL *s, int type)
 230         {
 231         int ret;
 232         int curr_mtu;
 233         unsigned int len, frag_off, mac_size, blocksize;
 234
 235         /* AHA!  Figure out the MTU, and stick to the right size */
 236         if (s->d1->mtu < dtls1_min_mtu() && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))
 237                 {
 238                 s->d1->mtu =
 239                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
 240
 241                 /* I've seen the kernel return bogus numbers when it doesn't know
 242                  * (initial write), so just make sure we have a reasonable number */
 243                 if (s->d1->mtu < dtls1_min_mtu())
 244                         {
 245                         s->d1->mtu = 0;
 246                         s->d1->mtu = dtls1_guess_mtu(s->d1->mtu);
 247                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
 248                                 s->d1->mtu, NULL);
 249                         }
 250                 }
 251 #if 0
 252         mtu = s->d1->mtu;
 253
 254         fprintf(stderr, "using MTU = %d\n", mtu);
 255
 256         mtu -= (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
 257
 258         curr_mtu = mtu - BIO_wpending(SSL_get_wbio(s));
 259
 260         if ( curr_mtu > 0)
 261                 mtu = curr_mtu;
 262         else if ( ( ret = BIO_flush(SSL_get_wbio(s))) <= 0)
 263                 return ret;
 264
 265         if ( BIO_wpending(SSL_get_wbio(s)) + s->init_num >= mtu)
 266                 {
 267                 ret = BIO_flush(SSL_get_wbio(s));
 268                 if ( ret <= 0)
 269                         return ret;
 270                 mtu = s->d1->mtu - (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
 271                 }
 272 #endif
 273
 274         OPENSSL_assert(s->d1->mtu >= dtls1_min_mtu());  /* should have something reasonable now */
 275
 276         if ( s->init_off == 0  && type == SSL3_RT_HANDSHAKE)
 277                 OPENSSL_assert(s->init_num ==
 278                         (int)s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH);
 279
 280         if (s->write_hash)
 281                 {
 282                 if (s->enc_write_ctx && EVP_CIPHER_CTX_mode(s->enc_write_ctx) == EVP_CIPH_GCM_MODE)
 283                         mac_size = 0;
 284                 else
 285                         mac_size = EVP_MD_CTX_size(s->write_hash);
 286                 }
 287         else
 288                 mac_size = 0;
 289
 290         if (s->enc_write_ctx &&
 291                 (EVP_CIPHER_CTX_mode(s->enc_write_ctx) == EVP_CIPH_CBC_MODE))
 292                 blocksize = 2 * EVP_CIPHER_block_size(s->enc_write_ctx->cipher);
 293         else
 294                 blocksize = 0;
 295
 296         frag_off = 0;
 297         while( s->init_num)
 298                 {
 299                 curr_mtu = s->d1->mtu - BIO_wpending(SSL_get_wbio(s)) -
 300                         DTLS1_RT_HEADER_LENGTH - mac_size - blocksize;
 301
 302                 if ( curr_mtu <= DTLS1_HM_HEADER_LENGTH)
 303                         {
 304                         /* grr.. we could get an error if MTU picked was wrong */
 305                         ret = BIO_flush(SSL_get_wbio(s));
 306                         if ( ret <= 0)
 307                                 return ret;
 308                         curr_mtu = s->d1->mtu - DTLS1_RT_HEADER_LENGTH -
 309                                 mac_size - blocksize;
 310                         }
 311
 312                 if ( s->init_num > curr_mtu)
 313                         len = curr_mtu;
 314                 else
 315                         len = s->init_num;
 316
 317
 318                 /* XDTLS: this function is too long.  split out the CCS part */
 319                 if ( type == SSL3_RT_HANDSHAKE)
 320                         {
 321                         if ( s->init_off != 0)
 322                                 {
 323                                 OPENSSL_assert(s->init_off > DTLS1_HM_HEADER_LENGTH);
 324                                 s->init_off -= DTLS1_HM_HEADER_LENGTH;
 325                                 s->init_num += DTLS1_HM_HEADER_LENGTH;
 326
 327                                 if ( s->init_num > curr_mtu)
 328                                         len = curr_mtu;
 329                                 else
 330                                         len = s->init_num;
 331                                 }
 332
 333                         dtls1_fix_message_header(s, frag_off,
 334                                 len - DTLS1_HM_HEADER_LENGTH);
 335
 336                         dtls1_write_message_header(s, (unsigned char *)&s->init_buf->data[s->init_off]);
 337
 338                         OPENSSL_assert(len >= DTLS1_HM_HEADER_LENGTH);
 339                         }
 340
 341                 ret=dtls1_write_bytes(s,type,&s->init_buf->data[s->init_off],
 342                         len);
 343                 if (ret < 0)
 344                         {
 345                         /* might need to update MTU here, but we don't know
 346                          * which previous packet caused the failure -- so can't
 347                          * really retransmit anything.  continue as if everything
 348                          * is fine and wait for an alert to handle the
 349                          * retransmit
 350                          */
 351                         if ( BIO_ctrl(SSL_get_wbio(s),
 352                                 BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0 )
 353                                 s->d1->mtu = BIO_ctrl(SSL_get_wbio(s),
 354                                         BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
 355                         else
 356                                 return(-1);
 357                         }
 358                 else
 359                         {
 360
 361                         /* bad if this assert fails, only part of the handshake
 362                          * message got sent.  but why would this happen? */
 363                         OPENSSL_assert(len == (unsigned int)ret);
 364
 365                         if (type == SSL3_RT_HANDSHAKE && ! s->d1->retransmitting)
 366                                 {
 367                                 /* should not be done for 'Hello Request's, but in that case
 368                                  * we'll ignore the result anyway */
 369                                 unsigned char *p = (unsigned char *)&s->init_buf->data[s->init_off];
 370                                 const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
 371                                 int xlen;
 372
 373                                 if (frag_off == 0 && s->version != DTLS1_BAD_VER)
 374                                         {
 375                                         /* reconstruct message header is if it
 376                                          * is being sent in single fragment */
 377                                         *p++ = msg_hdr->type;
 378                                         l2n3(msg_hdr->msg_len,p);
 379                                         s2n (msg_hdr->seq,p);
 380                                         l2n3(0,p);
 381                                         l2n3(msg_hdr->msg_len,p);
 382                                         p  -= DTLS1_HM_HEADER_LENGTH;
 383                                         xlen = ret;
 384                                         }
 385                                 else
 386                                         {
 387                                         p  += DTLS1_HM_HEADER_LENGTH;
 388                                         xlen = ret - DTLS1_HM_HEADER_LENGTH;
 389                                         }
 390
 391                                 ssl3_finish_mac(s, p, xlen);
 392                                 }
 393
 394                         if (ret == s->init_num)
 395                                 {
 396                                 if (s->msg_callback)
 397                                         s->msg_callback(1, s->version, type, s->init_buf->data,
 398                                                 (size_t)(s->init_off + s->init_num), s,
 399                                                 s->msg_callback_arg);
 400
 401                                 s->init_off = 0;  /* done writing this message */
 402                                 s->init_num = 0;
 403
 404                                 return(1);
 405                                 }
 406                         s->init_off+=ret;
 407                         s->init_num-=ret;
 408                         frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
 409                         }
 410                 }
 411         return(0);
 412         }
 413
 414
 415 /* Obtain handshake message of message type 'mt' (any if mt == -1),
 416  * maximum acceptable body length 'max'.
 417  * Read an entire handshake message.  Handshake messages arrive in
 418  * fragments.
 419  */
 420 long dtls1_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
 421         {
 422         int i, al;
 423         struct hm_header_st *msg_hdr;
 424         unsigned char *p;
 425         unsigned long msg_len;
 426
 427         /* s3->tmp is used to store messages that are unexpected, caused
 428          * by the absence of an optional handshake message */
 429         if (s->s3->tmp.reuse_message)
 430                 {
 431                 s->s3->tmp.reuse_message=0;
 432                 if ((mt >= 0) && (s->s3->tmp.message_type != mt))
 433                         {
 434                         al=SSL_AD_UNEXPECTED_MESSAGE;
 435                         SSLerr(SSL_F_DTLS1_GET_MESSAGE,SSL_R_UNEXPECTED_MESSAGE);
 436                         goto f_err;
 437                         }
 438                 *ok=1;
 439                 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 440                 s->init_num = (int)s->s3->tmp.message_size;
 441                 return s->init_num;
 442                 }
 443
 444         msg_hdr = &s->d1->r_msg_hdr;
 445         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
 446
 447 again:
 448         i = dtls1_get_message_fragment(s, st1, stn, max, ok);
 449         if ( i == DTLS1_HM_BAD_FRAGMENT ||
 450                 i == DTLS1_HM_FRAGMENT_RETRY)  /* bad fragment received */
 451                 goto again;
 452         else if ( i <= 0 && !*ok)
 453                 return i;
 454
 455         p = (unsigned char *)s->init_buf->data;
 456         msg_len = msg_hdr->msg_len;
 457
 458         /* reconstruct message header */
 459         *(p++) = msg_hdr->type;
 460         l2n3(msg_len,p);
 461         s2n (msg_hdr->seq,p);
 462         l2n3(0,p);
 463         l2n3(msg_len,p);
 464         if (s->version != DTLS1_BAD_VER) {
 465                 p       -= DTLS1_HM_HEADER_LENGTH;
 466                 msg_len += DTLS1_HM_HEADER_LENGTH;
 467         }
 468
 469         ssl3_finish_mac(s, p, msg_len);
 470         if (s->msg_callback)
 471                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 472                         p, msg_len,
 473                         s, s->msg_callback_arg);
 474
 475         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
 476
 477         /* Don't change sequence numbers while listening */
 478         if (!s->d1->listen)
 479                 s->d1->handshake_read_seq++;
 480
 481         s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 482         return s->init_num;
 483
 484 f_err:
 485         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 486         *ok = 0;
 487         return -1;
 488         }
 489
 490
 491 static int dtls1_preprocess_fragment(SSL *s,struct hm_header_st *msg_hdr,int max)
 492         {
 493         size_t frag_off,frag_len,msg_len;
 494
 495         msg_len  = msg_hdr->msg_len;
 496         frag_off = msg_hdr->frag_off;
 497         frag_len = msg_hdr->frag_len;
 498
 499         /* sanity checking */
 500         if ( (frag_off+frag_len) > msg_len)
 501                 {
 502                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 503                 return SSL_AD_ILLEGAL_PARAMETER;
 504                 }
 505
 506         if ( (frag_off+frag_len) > (unsigned long)max)
 507                 {
 508                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 509                 return SSL_AD_ILLEGAL_PARAMETER;
 510                 }
 511
 512         if ( s->d1->r_msg_hdr.frag_off == 0) /* first fragment */
 513                 {
 514                 /* msg_len is limited to 2^24, but is effectively checked
 515                  * against max above */
 516                 if (!BUF_MEM_grow_clean(s->init_buf,msg_len+DTLS1_HM_HEADER_LENGTH))
 517                         {
 518                         SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,ERR_R_BUF_LIB);
 519                         return SSL_AD_INTERNAL_ERROR;
 520                         }
 521
 522                 s->s3->tmp.message_size  = msg_len;
 523                 s->d1->r_msg_hdr.msg_len = msg_len;
 524                 s->s3->tmp.message_type  = msg_hdr->type;
 525                 s->d1->r_msg_hdr.type    = msg_hdr->type;
 526                 s->d1->r_msg_hdr.seq     = msg_hdr->seq;
 527                 }
 528         else if (msg_len != s->d1->r_msg_hdr.msg_len)
 529                 {
 530                 /* They must be playing with us! BTW, failure to enforce
 531                  * upper limit would open possibility for buffer overrun. */
 532                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 533                 return SSL_AD_ILLEGAL_PARAMETER;
 534                 }
 535
 536         return 0; /* no error */
 537         }
 538
 539
 540 static int
 541 dtls1_retrieve_buffered_fragment(SSL *s, long max, int *ok)
 542         {
 543         /* (0) check whether the desired fragment is available
 544          * if so:
 545          * (1) copy over the fragment to s->init_buf->data[]
 546          * (2) update s->init_num
 547          */
 548         pitem *item;
 549         hm_fragment *frag;
 550         int al;
 551
 552         *ok = 0;
 553         item = pqueue_peek(s->d1->buffered_messages);
 554         if ( item == NULL)
 555                 return 0;
 556
 557         frag = (hm_fragment *)item->data;
 558
 559         /* Don't return if reassembly still in progress */
 560         if (frag->reassembly != NULL)
 561                 return 0;
 562
 563         if ( s->d1->handshake_read_seq == frag->msg_header.seq)
 564                 {
 565                 unsigned long frag_len = frag->msg_header.frag_len;
 566                 pqueue_pop(s->d1->buffered_messages);
 567
 568                 al=dtls1_preprocess_fragment(s,&frag->msg_header,max);
 569
 570                 if (al==0) /* no alert */
 571                         {
 572                         unsigned char *p = (unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
 573                         memcpy(&p[frag->msg_header.frag_off],
 574                                 frag->fragment,frag->msg_header.frag_len);
 575                         }
 576
 577                 dtls1_hm_fragment_free(frag);
 578                 pitem_free(item);
 579
 580                 if (al==0)
 581                         {
 582                         *ok = 1;
 583                         return frag_len;
 584                         }
 585
 586                 ssl3_send_alert(s,SSL3_AL_FATAL,al);
 587                 s->init_num = 0;
 588                 *ok = 0;
 589                 return -1;
 590                 }
 591         else
 592                 return 0;
 593         }
 594
 595 /* dtls1_max_handshake_message_len returns the maximum number of bytes
 596  * permitted in a DTLS handshake message for |s|. The minimum is 16KB, but may
 597  * be greater if the maximum certificate list size requires it. */
 598 static unsigned long dtls1_max_handshake_message_len(const SSL *s)
 599         {
 600         unsigned long max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
 601         if (max_len < (unsigned long)s->max_cert_list)
 602                 return s->max_cert_list;
 603         return max_len;
 604         }
 605
 606 static int
 607 dtls1_reassemble_fragment(SSL *s, const struct hm_header_st* msg_hdr, int *ok)
 608         {
 609         hm_fragment *frag = NULL;
 610         pitem *item = NULL;
 611         int i = -1, is_complete;
 612         unsigned char seq64be[8];
 613         unsigned long frag_len = msg_hdr->frag_len;
 614
 615         if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len ||
 616             msg_hdr->msg_len > dtls1_max_handshake_message_len(s))
 617                 goto err;
 618
 619         if (frag_len == 0)
 620                 return DTLS1_HM_FRAGMENT_RETRY;
 621
 622         /* Try to find item in queue */
 623         memset(seq64be,0,sizeof(seq64be));
 624         seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
 625         seq64be[7] = (unsigned char) msg_hdr->seq;
 626         item = pqueue_find(s->d1->buffered_messages, seq64be);
 627
 628         if (item == NULL)
 629                 {
 630                 frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1);
 631                 if ( frag == NULL)
 632                         goto err;
 633                 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
 634                 frag->msg_header.frag_len = frag->msg_header.msg_len;
 635                 frag->msg_header.frag_off = 0;
 636                 }
 637         else
 638                 {
 639                 frag = (hm_fragment*) item->data;
 640                 if (frag->msg_header.msg_len != msg_hdr->msg_len)
 641                         {
 642                         item = NULL;
 643                         frag = NULL;
 644                         goto err;
 645                         }
 646                 }
 647
 648
 649         /* If message is already reassembled, this must be a
 650          * retransmit and can be dropped. In this case item != NULL and so frag
 651          * does not need to be freed.
 652          */
 653         if (frag->reassembly == NULL)
 654                 {
 655                 unsigned char devnull [256];
 656
 657                 while (frag_len)
 658                         {
 659                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 660                                 devnull,
 661                                 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
 662                         if (i<=0) goto err;
 663                         frag_len -= i;
 664                         }
 665                 return DTLS1_HM_FRAGMENT_RETRY;
 666                 }
 667
 668         /* read the body of the fragment (header has already been read */
 669         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 670                 frag->fragment + msg_hdr->frag_off,frag_len,0);
 671         if ((unsigned long)i!=frag_len)
 672                 i=-1;
 673         if (i<=0)
 674                 goto err;
 675
 676         RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off,
 677                             (long)(msg_hdr->frag_off + frag_len));
 678
 679         RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len,
 680                                    is_complete);
 681
 682         if (is_complete)
 683                 {
 684                 OPENSSL_free(frag->reassembly);
 685                 frag->reassembly = NULL;
 686                 }
 687
 688         if (item == NULL)
 689                 {
 690                 item = pitem_new(seq64be, frag);
 691                 if (item == NULL)
 692                         {
 693                         i = -1;
 694                         goto err;
 695                         }
 696
 697                 item = pqueue_insert(s->d1->buffered_messages, item);
 698                 /* pqueue_insert fails iff a duplicate item is inserted.
 699                  * However, |item| cannot be a duplicate. If it were,
 700                  * |pqueue_find|, above, would have returned it and control
 701                  * would never have reached this branch. */
 702                 OPENSSL_assert(item != NULL);
 703                 }
 704
 705         return DTLS1_HM_FRAGMENT_RETRY;
 706
 707 err:
 708         if (frag != NULL && item == NULL) dtls1_hm_fragment_free(frag);
 709         *ok = 0;
 710         return i;
 711         }
 712
 713
 714 static int
 715 dtls1_process_out_of_seq_message(SSL *s, const struct hm_header_st* msg_hdr, int *ok)
 716 {
 717         int i=-1;
 718         hm_fragment *frag = NULL;
 719         pitem *item = NULL;
 720         unsigned char seq64be[8];
 721         unsigned long frag_len = msg_hdr->frag_len;
 722
 723         if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len)
 724                 goto err;
 725
 726         /* Try to find item in queue, to prevent duplicate entries */
 727         memset(seq64be,0,sizeof(seq64be));
 728         seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
 729         seq64be[7] = (unsigned char) msg_hdr->seq;
 730         item = pqueue_find(s->d1->buffered_messages, seq64be);
 731
 732         /* If we already have an entry and this one is a fragment,
 733          * don't discard it and rather try to reassemble it.
 734          */
 735         if (item != NULL && frag_len != msg_hdr->msg_len)
 736                 item = NULL;
 737
 738         /* Discard the message if sequence number was already there, is
 739          * too far in the future, already in the queue or if we received
 740          * a FINISHED before the SERVER_HELLO, which then must be a stale
 741          * retransmit.
 742          */
 743         if (msg_hdr->seq <= s->d1->handshake_read_seq ||
 744                 msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL ||
 745                 (s->d1->handshake_read_seq == 0 && msg_hdr->type == SSL3_MT_FINISHED))
 746                 {
 747                 unsigned char devnull [256];
 748
 749                 while (frag_len)
 750                         {
 751                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 752                                 devnull,
 753                                 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
 754                         if (i<=0) goto err;
 755                         frag_len -= i;
 756                         }
 757                 }
 758         else
 759                 {
 760                 if (frag_len != msg_hdr->msg_len)
 761                         return dtls1_reassemble_fragment(s, msg_hdr, ok);
 762
 763                 if (frag_len > dtls1_max_handshake_message_len(s))
 764                         goto err;
 765
 766                 frag = dtls1_hm_fragment_new(frag_len, 0);
 767                 if ( frag == NULL)
 768                         goto err;
 769
 770                 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
 771
 772                 if (frag_len)
 773                         {
 774                         /* read the body of the fragment (header has already been read */
 775                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 776                                 frag->fragment,frag_len,0);
 777                         if ((unsigned long)i!=frag_len)
 778                                 i = -1;
 779                         if (i<=0)
 780                                 goto err;
 781                         }
 782
 783                 item = pitem_new(seq64be, frag);
 784                 if ( item == NULL)
 785                         goto err;
 786
 787                 item = pqueue_insert(s->d1->buffered_messages, item);
 788                 /* pqueue_insert fails iff a duplicate item is inserted.
 789                  * However, |item| cannot be a duplicate. If it were,
 790                  * |pqueue_find|, above, would have returned it. Then, either
 791                  * |frag_len| != |msg_hdr->msg_len| in which case |item| is set
 792                  * to NULL and it will have been processed with
 793                  * |dtls1_reassemble_fragment|, above, or the record will have
 794                  * been discarded. */
 795                 OPENSSL_assert(item != NULL);
 796                 }
 797
 798         return DTLS1_HM_FRAGMENT_RETRY;
 799
 800 err:
 801         if (frag != NULL && item == NULL) dtls1_hm_fragment_free(frag);
 802         *ok = 0;
 803         return i;
 804         }
 805
 806
 807 static long
 808 dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
 809         {
 810         unsigned char wire[DTLS1_HM_HEADER_LENGTH];
 811         unsigned long len, frag_off, frag_len;
 812         int i,al;
 813         struct hm_header_st msg_hdr;
 814
 815         redo:
 816         /* see if we have the required fragment already */
 817         if ((frag_len = dtls1_retrieve_buffered_fragment(s,max,ok)) || *ok)
 818                 {
 819                 if (*ok)        s->init_num = frag_len;
 820                 return frag_len;
 821                 }
 822
 823         /* read handshake message header */
 824         i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,wire,
 825                 DTLS1_HM_HEADER_LENGTH, 0);
 826         if (i <= 0)     /* nbio, or an error */
 827                 {
 828                 s->rwstate=SSL_READING;
 829                 *ok = 0;
 830                 return i;
 831                 }
 832         /* Handshake fails if message header is incomplete */
 833         if (i != DTLS1_HM_HEADER_LENGTH)
 834                 {
 835                 al=SSL_AD_UNEXPECTED_MESSAGE;
 836                 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
 837                 goto f_err;
 838                 }
 839
 840         /* parse the message fragment header */
 841         dtls1_get_message_header(wire, &msg_hdr);
 842
 843         /*
 844          * if this is a future (or stale) message it gets buffered
 845          * (or dropped)--no further processing at this time
 846          * While listening, we accept seq 1 (ClientHello with cookie)
 847          * although we're still expecting seq 0 (ClientHello)
 848          */
 849         if (msg_hdr.seq != s->d1->handshake_read_seq && !(s->d1->listen && msg_hdr.seq == 1))
 850                 return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
 851
 852         len = msg_hdr.msg_len;
 853         frag_off = msg_hdr.frag_off;
 854         frag_len = msg_hdr.frag_len;
 855
 856         if (frag_len && frag_len < len)
 857                 return dtls1_reassemble_fragment(s, &msg_hdr, ok);
 858
 859         if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
 860                 wire[0] == SSL3_MT_HELLO_REQUEST)
 861                 {
 862                 /* The server may always send 'Hello Request' messages --
 863                  * we are doing a handshake anyway now, so ignore them
 864                  * if their format is correct. Does not count for
 865                  * 'Finished' MAC. */
 866                 if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0)
 867                         {
 868                         if (s->msg_callback)
 869                                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 870                                         wire, DTLS1_HM_HEADER_LENGTH, s,
 871                                         s->msg_callback_arg);
 872
 873                         s->init_num = 0;
 874                         goto redo;
 875                         }
 876                 else /* Incorrectly formated Hello request */
 877                         {
 878                         al=SSL_AD_UNEXPECTED_MESSAGE;
 879                         SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
 880                         goto f_err;
 881                         }
 882                 }
 883
 884         if ((al=dtls1_preprocess_fragment(s,&msg_hdr,max)))
 885                 goto f_err;
 886
 887         /* XDTLS:  ressurect this when restart is in place */
 888         s->state=stn;
 889
 890         if ( frag_len > 0)
 891                 {
 892                 unsigned char *p=(unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
 893
 894                 i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 895                         &p[frag_off],frag_len,0);
 896                 /* XDTLS:  fix this--message fragments cannot span multiple packets */
 897                 if (i <= 0)
 898                         {
 899                         s->rwstate=SSL_READING;
 900                         *ok = 0;
 901                         return i;
 902                         }
 903                 }
 904         else
 905                 i = 0;
 906
 907         /* XDTLS:  an incorrectly formatted fragment should cause the
 908          * handshake to fail */
 909         if (i != (int)frag_len)
 910                 {
 911                 al=SSL3_AD_ILLEGAL_PARAMETER;
 912                 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL3_AD_ILLEGAL_PARAMETER);
 913                 goto f_err;
 914                 }
 915
 916         *ok = 1;
 917
 918         /* Note that s->init_num is *not* used as current offset in
 919          * s->init_buf->data, but as a counter summing up fragments'
 920          * lengths: as soon as they sum up to handshake packet
 921          * length, we assume we have got all the fragments. */
 922         s->init_num = frag_len;
 923         return frag_len;
 924
 925 f_err:
 926         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 927         s->init_num = 0;
 928
 929         *ok=0;
 930         return(-1);
 931         }
 932
 933 /* for these 2 messages, we need to
 934  * ssl->enc_read_ctx                    re-init
 935  * ssl->s3->read_sequence               zero
 936  * ssl->s3->read_mac_secret             re-init
 937  * ssl->session->read_sym_enc           assign
 938  * ssl->session->read_compression       assign
 939  * ssl->session->read_hash              assign
 940  */
 941 int dtls1_send_change_cipher_spec(SSL *s, int a, int b)
 942         {
 943         unsigned char *p;
 944
 945         if (s->state == a)
 946                 {
 947                 p=(unsigned char *)s->init_buf->data;
 948                 *p++=SSL3_MT_CCS;
 949                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
 950                 s->init_num=DTLS1_CCS_HEADER_LENGTH;
 951
 952                 if (s->version == DTLS1_BAD_VER) {
 953                         s->d1->next_handshake_write_seq++;
 954                         s2n(s->d1->handshake_write_seq,p);
 955                         s->init_num+=2;
 956                 }
 957
 958                 s->init_off=0;
 959
 960                 dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
 961                         s->d1->handshake_write_seq, 0, 0);
 962
 963                 /* buffer the message to handle re-xmits */
 964                 dtls1_buffer_message(s, 1);
 965
 966                 s->state=b;
 967                 }
 968
 969         /* SSL3_ST_CW_CHANGE_B */
 970         return(dtls1_do_write(s,SSL3_RT_CHANGE_CIPHER_SPEC));
 971         }
 972
 973 int dtls1_read_failed(SSL *s, int code)
 974         {
 975         if ( code > 0)
 976                 {
 977                 fprintf( stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
 978                 return 1;
 979                 }
 980
 981         if (!dtls1_is_timer_expired(s))
 982                 {
 983                 /* not a timeout, none of our business,
 984                    let higher layers handle this.  in fact it's probably an error */
 985                 return code;
 986                 }
 987
 988 #ifndef OPENSSL_NO_HEARTBEATS
 989         if (!SSL_in_init(s) && !s->tlsext_hb_pending)  /* done, no need to send a retransmit */
 990 #else
 991         if (!SSL_in_init(s))  /* done, no need to send a retransmit */
 992 #endif
 993                 {
 994                 BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
 995                 return code;
 996                 }
 997
 998 #if 0 /* for now, each alert contains only one record number */
 999         item = pqueue_peek(state->rcvd_records);
1000         if ( item )
1001                 {
1002                 /* send an alert immediately for all the missing records */
1003                 }
1004         else
1005 #endif
1006
1007 #if 0  /* no more alert sending, just retransmit the last set of messages */
1008         if ( state->timeout.read_timeouts >= DTLS1_TMO_READ_COUNT)
1009                 ssl3_send_alert(s,SSL3_AL_WARNING,
1010                         DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
1011 #endif
1012
1013         return dtls1_handle_timeout(s);
1014         }
1015
1016 int
1017 dtls1_get_queue_priority(unsigned short seq, int is_ccs)
1018         {
1019         /* The index of the retransmission queue actually is the message sequence number,
1020          * since the queue only contains messages of a single handshake. However, the
1021          * ChangeCipherSpec has no message sequence number and so using only the sequence
1022          * will result in the CCS and Finished having the same index. To prevent this,
1023          * the sequence number is multiplied by 2. In case of a CCS 1 is subtracted.
1024          * This does not only differ CSS and Finished, it also maintains the order of the
1025          * index (important for priority queues) and fits in the unsigned short variable.
1026          */
1027         return seq * 2 - is_ccs;
1028         }
1029
1030 int
1031 dtls1_retransmit_buffered_messages(SSL *s)
1032         {
1033         pqueue sent = s->d1->sent_messages;
1034         piterator iter;
1035         pitem *item;
1036         hm_fragment *frag;
1037         int found = 0;
1038
1039         iter = pqueue_iterator(sent);
1040
1041         for ( item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter))
1042                 {
1043                 frag = (hm_fragment *)item->data;
1044                         if ( dtls1_retransmit_message(s,
1045                                 (unsigned short)dtls1_get_queue_priority(frag->msg_header.seq, frag->msg_header.is_ccs),
1046                                 0, &found) <= 0 && found)
1047                         {
1048                         fprintf(stderr, "dtls1_retransmit_message() failed\n");
1049                         return -1;
1050                         }
1051                 }
1052
1053         return 1;
1054         }
1055
1056 int
1057 dtls1_buffer_message(SSL *s, int is_ccs)
1058         {
1059         pitem *item;
1060         hm_fragment *frag;
1061         unsigned char seq64be[8];
1062
1063         /* this function is called immediately after a message has
1064          * been serialized */
1065         OPENSSL_assert(s->init_off == 0);
1066
1067         frag = dtls1_hm_fragment_new(s->init_num, 0);
1068         if (!frag)
1069                 return 0;
1070
1071         memcpy(frag->fragment, s->init_buf->data, s->init_num);
1072
1073         if ( is_ccs)
1074                 {
1075                 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1076                                DTLS1_CCS_HEADER_LENGTH == (unsigned int)s->init_num);
1077                 }
1078         else
1079                 {
1080                 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1081                         DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num);
1082                 }
1083
1084         frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
1085         frag->msg_header.seq = s->d1->w_msg_hdr.seq;
1086         frag->msg_header.type = s->d1->w_msg_hdr.type;
1087         frag->msg_header.frag_off = 0;
1088         frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
1089         frag->msg_header.is_ccs = is_ccs;
1090
1091         /* save current state*/
1092         frag->msg_header.saved_retransmit_state.enc_write_ctx = s->enc_write_ctx;
1093         frag->msg_header.saved_retransmit_state.write_hash = s->write_hash;
1094         frag->msg_header.saved_retransmit_state.compress = s->compress;
1095         frag->msg_header.saved_retransmit_state.session = s->session;
1096         frag->msg_header.saved_retransmit_state.epoch = s->d1->w_epoch;
1097
1098         memset(seq64be,0,sizeof(seq64be));
1099         seq64be[6] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1100                                                                                                                   frag->msg_header.is_ccs)>>8);
1101         seq64be[7] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1102                                                                                                                   frag->msg_header.is_ccs));
1103
1104         item = pitem_new(seq64be, frag);
1105         if ( item == NULL)
1106                 {
1107                 dtls1_hm_fragment_free(frag);
1108                 return 0;
1109                 }
1110
1111 #if 0
1112         fprintf( stderr, "buffered messge: \ttype = %xx\n", msg_buf->type);
1113         fprintf( stderr, "\t\t\t\t\tlen = %d\n", msg_buf->len);
1114         fprintf( stderr, "\t\t\t\t\tseq_num = %d\n", msg_buf->seq_num);
1115 #endif
1116
1117         pqueue_insert(s->d1->sent_messages, item);
1118         return 1;
1119         }
1120
1121 int
1122 dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
1123         int *found)
1124         {
1125         int ret;
1126         /* XDTLS: for now assuming that read/writes are blocking */
1127         pitem *item;
1128         hm_fragment *frag ;
1129         unsigned long header_length;
1130         unsigned char seq64be[8];
1131         struct dtls1_retransmit_state saved_state;
1132         unsigned char save_write_sequence[8];
1133
1134         /*
1135           OPENSSL_assert(s->init_num == 0);
1136           OPENSSL_assert(s->init_off == 0);
1137          */
1138
1139         /* XDTLS:  the requested message ought to be found, otherwise error */
1140         memset(seq64be,0,sizeof(seq64be));
1141         seq64be[6] = (unsigned char)(seq>>8);
1142         seq64be[7] = (unsigned char)seq;
1143
1144         item = pqueue_find(s->d1->sent_messages, seq64be);
1145         if ( item == NULL)
1146                 {
1147                 fprintf(stderr, "retransmit:  message %d non-existant\n", seq);
1148                 *found = 0;
1149                 return 0;
1150                 }
1151
1152         *found = 1;
1153         frag = (hm_fragment *)item->data;
1154
1155         if ( frag->msg_header.is_ccs)
1156                 header_length = DTLS1_CCS_HEADER_LENGTH;
1157         else
1158                 header_length = DTLS1_HM_HEADER_LENGTH;
1159
1160         memcpy(s->init_buf->data, frag->fragment,
1161                 frag->msg_header.msg_len + header_length);
1162                 s->init_num = frag->msg_header.msg_len + header_length;
1163
1164         dtls1_set_message_header_int(s, frag->msg_header.type,
1165                 frag->msg_header.msg_len, frag->msg_header.seq, 0,
1166                 frag->msg_header.frag_len);
1167
1168         /* save current state */
1169         saved_state.enc_write_ctx = s->enc_write_ctx;
1170         saved_state.write_hash = s->write_hash;
1171         saved_state.compress = s->compress;
1172         saved_state.session = s->session;
1173         saved_state.epoch = s->d1->w_epoch;
1174         saved_state.epoch = s->d1->w_epoch;
1175
1176         s->d1->retransmitting = 1;
1177
1178         /* restore state in which the message was originally sent */
1179         s->enc_write_ctx = frag->msg_header.saved_retransmit_state.enc_write_ctx;
1180         s->write_hash = frag->msg_header.saved_retransmit_state.write_hash;
1181         s->compress = frag->msg_header.saved_retransmit_state.compress;
1182         s->session = frag->msg_header.saved_retransmit_state.session;
1183         s->d1->w_epoch = frag->msg_header.saved_retransmit_state.epoch;
1184
1185         if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1186         {
1187                 memcpy(save_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1188                 memcpy(s->s3->write_sequence, s->d1->last_write_sequence, sizeof(s->s3->write_sequence));
1189         }
1190
1191         ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1192                                                  SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1193
1194         /* restore current state */
1195         s->enc_write_ctx = saved_state.enc_write_ctx;
1196         s->write_hash = saved_state.write_hash;
1197         s->compress = saved_state.compress;
1198         s->session = saved_state.session;
1199         s->d1->w_epoch = saved_state.epoch;
1200
1201         if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1202         {
1203                 memcpy(s->d1->last_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1204                 memcpy(s->s3->write_sequence, save_write_sequence, sizeof(s->s3->write_sequence));
1205         }
1206
1207         s->d1->retransmitting = 0;
1208
1209         (void)BIO_flush(SSL_get_wbio(s));
1210         return ret;
1211         }
1212
1213 /* call this function when the buffered messages are no longer needed */
1214 void
1215 dtls1_clear_record_buffer(SSL *s)
1216         {
1217         pitem *item;
1218
1219         for(item = pqueue_pop(s->d1->sent_messages);
1220                 item != NULL; item = pqueue_pop(s->d1->sent_messages))
1221                 {
1222                 dtls1_hm_fragment_free((hm_fragment *)item->data);
1223                 pitem_free(item);
1224                 }
1225         }
1226
1227
1228 unsigned char *
1229 dtls1_set_message_header(SSL *s, unsigned char *p, unsigned char mt,
1230                         unsigned long len, unsigned long frag_off, unsigned long frag_len)
1231         {
1232         /* Don't change sequence numbers while listening */
1233         if (frag_off == 0 && !s->d1->listen)
1234                 {
1235                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1236                 s->d1->next_handshake_write_seq++;
1237                 }
1238
1239         dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1240                 frag_off, frag_len);
1241
1242         return p += DTLS1_HM_HEADER_LENGTH;
1243         }
1244
1245
1246 /* don't actually do the writing, wait till the MTU has been retrieved */
1247 static void
1248 dtls1_set_message_header_int(SSL *s, unsigned char mt,
1249                             unsigned long len, unsigned short seq_num, unsigned long frag_off,
1250                             unsigned long frag_len)
1251         {
1252         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1253
1254         msg_hdr->type = mt;
1255         msg_hdr->msg_len = len;
1256         msg_hdr->seq = seq_num;
1257         msg_hdr->frag_off = frag_off;
1258         msg_hdr->frag_len = frag_len;
1259         }
1260
1261 static void
1262 dtls1_fix_message_header(SSL *s, unsigned long frag_off,
1263                         unsigned long frag_len)
1264         {
1265         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1266
1267         msg_hdr->frag_off = frag_off;
1268         msg_hdr->frag_len = frag_len;
1269         }
1270
1271 static unsigned char *
1272 dtls1_write_message_header(SSL *s, unsigned char *p)
1273         {
1274         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1275
1276         *p++ = msg_hdr->type;
1277         l2n3(msg_hdr->msg_len, p);
1278
1279         s2n(msg_hdr->seq, p);
1280         l2n3(msg_hdr->frag_off, p);
1281         l2n3(msg_hdr->frag_len, p);
1282
1283         return p;
1284         }
1285
1286 unsigned int
1287 dtls1_min_mtu(void)
1288         {
1289         return (g_probable_mtu[(sizeof(g_probable_mtu) /
1290                 sizeof(g_probable_mtu[0])) - 1]);
1291         }
1292
1293 static unsigned int
1294 dtls1_guess_mtu(unsigned int curr_mtu)
1295         {
1296         unsigned int i;
1297
1298         if ( curr_mtu == 0 )
1299                 return g_probable_mtu[0] ;
1300
1301         for ( i = 0; i < sizeof(g_probable_mtu)/sizeof(g_probable_mtu[0]); i++)
1302                 if ( curr_mtu > g_probable_mtu[i])
1303                         return g_probable_mtu[i];
1304
1305         return curr_mtu;
1306         }
1307
1308 void
1309 dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
1310         {
1311         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
1312         msg_hdr->type = *(data++);
1313         n2l3(data, msg_hdr->msg_len);
1314
1315         n2s(data, msg_hdr->seq);
1316         n2l3(data, msg_hdr->frag_off);
1317         n2l3(data, msg_hdr->frag_len);
1318         }
1319
1320 void
1321 dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st *ccs_hdr)
1322         {
1323         memset(ccs_hdr, 0x00, sizeof(struct ccs_header_st));
1324
1325         ccs_hdr->type = *(data++);
1326         }
1327
1328 int dtls1_shutdown(SSL *s)
1329         {
1330         int ret;
1331 #ifndef OPENSSL_NO_SCTP
1332         if (BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
1333             !(s->shutdown & SSL_SENT_SHUTDOWN))
1334                 {
1335                 ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
1336                 if (ret < 0) return -1;
1337
1338                 if (ret == 0)
1339                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1, NULL);
1340                 }
1341 #endif
1342         ret = ssl3_shutdown(s);
1343 #ifndef OPENSSL_NO_SCTP
1344         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
1345 #endif
1346         return ret;
1347         }
1348
1349 #ifndef OPENSSL_NO_HEARTBEATS
1350 int
1351 dtls1_process_heartbeat(SSL *s)
1352         {
1353         unsigned char *p = &s->s3->rrec.data[0], *pl;
1354         unsigned short hbtype;
1355         unsigned int payload;
1356         unsigned int padding = 16; /* Use minimum padding */
1357
1358         if (s->msg_callback)
1359                 s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
1360                         &s->s3->rrec.data[0], s->s3->rrec.length,
1361                         s, s->msg_callback_arg);
1362
1363         /* Read type and payload length first */
1364         if (1 + 2 + 16 > s->s3->rrec.length)
1365                 return 0; /* silently discard */
1366         if (s->s3->rrec.length > SSL3_RT_MAX_PLAIN_LENGTH)
1367                 return 0; /* silently discard per RFC 6520 sec. 4 */
1368
1369         hbtype = *p++;
1370         n2s(p, payload);
1371         if (1 + 2 + payload + 16 > s->s3->rrec.length)
1372                 return 0; /* silently discard per RFC 6520 sec. 4 */
1373         pl = p;
1374
1375         if (hbtype == TLS1_HB_REQUEST)
1376                 {
1377                 unsigned char *buffer, *bp;
1378                 unsigned int write_length = 1 /* heartbeat type */ +
1379                                             2 /* heartbeat length */ +
1380                                             payload + padding;
1381                 int r;
1382
1383                 if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
1384                         return 0;
1385
1386                 /* Allocate memory for the response, size is 1 byte
1387                  * message type, plus 2 bytes payload length, plus
1388                  * payload, plus padding
1389                  */
1390                 buffer = OPENSSL_malloc(write_length);
1391                 bp = buffer;
1392
1393                 /* Enter response type, length and copy payload */
1394                 *bp++ = TLS1_HB_RESPONSE;
1395                 s2n(payload, bp);
1396                 memcpy(bp, pl, payload);
1397                 bp += payload;
1398                 /* Random padding */
1399                 RAND_pseudo_bytes(bp, padding);
1400
1401                 r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, write_length);
1402
1403                 if (r >= 0 && s->msg_callback)
1404                         s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1405                                 buffer, write_length,
1406                                 s, s->msg_callback_arg);
1407
1408                 OPENSSL_free(buffer);
1409
1410                 if (r < 0)
1411                         return r;
1412                 }
1413         else if (hbtype == TLS1_HB_RESPONSE)
1414                 {
1415                 unsigned int seq;
1416
1417                 /* We only send sequence numbers (2 bytes unsigned int),
1418                  * and 16 random bytes, so we just try to read the
1419                  * sequence number */
1420                 n2s(pl, seq);
1421
1422                 if (payload == 18 && seq == s->tlsext_hb_seq)
1423                         {
1424                         dtls1_stop_timer(s);
1425                         s->tlsext_hb_seq++;
1426                         s->tlsext_hb_pending = 0;
1427                         }
1428                 }
1429
1430         return 0;
1431         }
1432
1433 int
1434 dtls1_heartbeat(SSL *s)
1435         {
1436         unsigned char *buf, *p;
1437         int ret;
1438         unsigned int payload = 18; /* Sequence number + random bytes */
1439         unsigned int padding = 16; /* Use minimum padding */
1440
1441         /* Only send if peer supports and accepts HB requests... */
1442         if (!(s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED) ||
1443             s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS)
1444                 {
1445                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
1446                 return -1;
1447                 }
1448
1449         /* ...and there is none in flight yet... */
1450         if (s->tlsext_hb_pending)
1451                 {
1452                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PENDING);
1453                 return -1;
1454                 }
1455
1456         /* ...and no handshake in progress. */
1457         if (SSL_in_init(s) || s->in_handshake)
1458                 {
1459                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_UNEXPECTED_MESSAGE);
1460                 return -1;
1461                 }
1462
1463         /* Check if padding is too long, payload and padding
1464          * must not exceed 2^14 - 3 = 16381 bytes in total.
1465          */
1466         OPENSSL_assert(payload + padding <= 16381);
1467
1468         /* Create HeartBeat message, we just use a sequence number
1469          * as payload to distuingish different messages and add
1470          * some random stuff.
1471          *  - Message Type, 1 byte
1472          *  - Payload Length, 2 bytes (unsigned int)
1473          *  - Payload, the sequence number (2 bytes uint)
1474          *  - Payload, random bytes (16 bytes uint)
1475          *  - Padding
1476          */
1477         buf = OPENSSL_malloc(1 + 2 + payload + padding);
1478         p = buf;
1479         /* Message Type */
1480         *p++ = TLS1_HB_REQUEST;
1481         /* Payload length (18 bytes here) */
1482         s2n(payload, p);
1483         /* Sequence number */
1484         s2n(s->tlsext_hb_seq, p);
1485         /* 16 random bytes */
1486         RAND_pseudo_bytes(p, 16);
1487         p += 16;
1488         /* Random padding */
1489         RAND_pseudo_bytes(p, padding);
1490
1491         ret = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buf, 3 + payload + padding);
1492         if (ret >= 0)
1493                 {
1494                 if (s->msg_callback)
1495                         s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1496                                 buf, 3 + payload + padding,
1497                                 s, s->msg_callback_arg);
1498
1499                 dtls1_start_timer(s);
1500                 s->tlsext_hb_pending = 1;
1501                 }
1502
1503         OPENSSL_free(buf);
1504
1505         return ret;
1506         }
1507 #endif