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 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
 596 static int
 597 dtls1_reassemble_fragment(SSL *s, struct hm_header_st* msg_hdr, int *ok)
 598         {
 599         hm_fragment *frag = NULL;
 600         pitem *item = NULL;
 601         int i = -1, is_complete;
 602         unsigned char seq64be[8];
 603         unsigned long frag_len = msg_hdr->frag_len, max_len;
 604
 605         if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len)
 606                 goto err;
 607
 608         /* Determine maximum allowed message size. Depends on (user set)
 609          * maximum certificate length, but 16k is minimum.
 610          */
 611         if (DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH < s->max_cert_list)
 612                 max_len = s->max_cert_list;
 613         else
 614                 max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
 615
 616         if ((msg_hdr->frag_off+frag_len) > max_len)
 617                 goto err;
 618
 619         /* Try to find item in queue */
 620         memset(seq64be,0,sizeof(seq64be));
 621         seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
 622         seq64be[7] = (unsigned char) msg_hdr->seq;
 623         item = pqueue_find(s->d1->buffered_messages, seq64be);
 624
 625         if (item == NULL)
 626                 {
 627                 frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1);
 628                 if ( frag == NULL)
 629                         goto err;
 630                 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
 631                 frag->msg_header.frag_len = frag->msg_header.msg_len;
 632                 frag->msg_header.frag_off = 0;
 633                 }
 634         else
 635                 {
 636                 frag = (hm_fragment*) item->data;
 637                 if (frag->msg_header.msg_len != msg_hdr->msg_len)
 638                         {
 639                         item = NULL;
 640                         frag = NULL;
 641                         goto err;
 642                         }
 643                 }
 644
 645
 646         /* If message is already reassembled, this must be a
 647          * retransmit and can be dropped. In this case item != NULL and so frag
 648          * does not need to be freed.
 649          */
 650         if (frag->reassembly == NULL)
 651                 {
 652                 unsigned char devnull [256];
 653
 654                 while (frag_len)
 655                         {
 656                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 657                                 devnull,
 658                                 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
 659                         if (i<=0) goto err;
 660                         frag_len -= i;
 661                         }
 662                 return DTLS1_HM_FRAGMENT_RETRY;
 663                 }
 664
 665         /* read the body of the fragment (header has already been read */
 666         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 667                 frag->fragment + msg_hdr->frag_off,frag_len,0);
 668         if (i<=0 || (unsigned long)i!=frag_len)
 669                 goto err;
 670
 671         RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off,
 672                             (long)(msg_hdr->frag_off + frag_len));
 673
 674         RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len,
 675                                    is_complete);
 676
 677         if (is_complete)
 678                 {
 679                 OPENSSL_free(frag->reassembly);
 680                 frag->reassembly = NULL;
 681                 }
 682
 683         if (item == NULL)
 684                 {
 685                 memset(seq64be,0,sizeof(seq64be));
 686                 seq64be[6] = (unsigned char)(msg_hdr->seq>>8);
 687                 seq64be[7] = (unsigned char)(msg_hdr->seq);
 688
 689                 item = pitem_new(seq64be, frag);
 690                 if (item == NULL)
 691                         {
 692                         i = -1;
 693                         goto err;
 694                         }
 695
 696                 pqueue_insert(s->d1->buffered_messages, item);
 697                 }
 698
 699         return DTLS1_HM_FRAGMENT_RETRY;
 700
 701 err:
 702         if (frag != NULL && item == NULL) dtls1_hm_fragment_free(frag);
 703         *ok = 0;
 704         return i;
 705         }
 706
 707
 708 static int
 709 dtls1_process_out_of_seq_message(SSL *s, struct hm_header_st* msg_hdr, int *ok)
 710 {
 711         int i=-1;
 712         hm_fragment *frag = NULL;
 713         pitem *item = NULL;
 714         unsigned char seq64be[8];
 715         unsigned long frag_len = msg_hdr->frag_len;
 716
 717         if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len)
 718                 goto err;
 719
 720         /* Try to find item in queue, to prevent duplicate entries */
 721         memset(seq64be,0,sizeof(seq64be));
 722         seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
 723         seq64be[7] = (unsigned char) msg_hdr->seq;
 724         item = pqueue_find(s->d1->buffered_messages, seq64be);
 725
 726         /* If we already have an entry and this one is a fragment,
 727          * don't discard it and rather try to reassemble it.
 728          */
 729         if (item != NULL && frag_len < msg_hdr->msg_len)
 730                 item = NULL;
 731
 732         /* Discard the message if sequence number was already there, is
 733          * too far in the future, already in the queue or if we received
 734          * a FINISHED before the SERVER_HELLO, which then must be a stale
 735          * retransmit.
 736          */
 737         if (msg_hdr->seq <= s->d1->handshake_read_seq ||
 738                 msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL ||
 739                 (s->d1->handshake_read_seq == 0 && msg_hdr->type == SSL3_MT_FINISHED))
 740                 {
 741                 unsigned char devnull [256];
 742
 743                 while (frag_len)
 744                         {
 745                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 746                                 devnull,
 747                                 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
 748                         if (i<=0) goto err;
 749                         frag_len -= i;
 750                         }
 751                 }
 752         else
 753                 {
 754                 if (frag_len && frag_len < msg_hdr->msg_len)
 755                         return dtls1_reassemble_fragment(s, msg_hdr, ok);
 756
 757                 frag = dtls1_hm_fragment_new(frag_len, 0);
 758                 if ( frag == NULL)
 759                         goto err;
 760
 761                 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
 762
 763                 if (frag_len)
 764                         {
 765                         /* read the body of the fragment (header has already been read */
 766                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 767                                 frag->fragment,frag_len,0);
 768                         if (i<=0 || (unsigned long)i!=frag_len)
 769                                 goto err;
 770                         }
 771
 772                 memset(seq64be,0,sizeof(seq64be));
 773                 seq64be[6] = (unsigned char)(msg_hdr->seq>>8);
 774                 seq64be[7] = (unsigned char)(msg_hdr->seq);
 775
 776                 item = pitem_new(seq64be, frag);
 777                 if ( item == NULL)
 778                         goto err;
 779
 780                 pqueue_insert(s->d1->buffered_messages, item);
 781                 }
 782
 783         return DTLS1_HM_FRAGMENT_RETRY;
 784
 785 err:
 786         if (frag != NULL && item == NULL) dtls1_hm_fragment_free(frag);
 787         *ok = 0;
 788         return i;
 789         }
 790
 791
 792 static long
 793 dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
 794         {
 795         unsigned char wire[DTLS1_HM_HEADER_LENGTH];
 796         unsigned long len, frag_off, frag_len;
 797         int i,al;
 798         struct hm_header_st msg_hdr;
 799
 800         redo:
 801         /* see if we have the required fragment already */
 802         if ((frag_len = dtls1_retrieve_buffered_fragment(s,max,ok)) || *ok)
 803                 {
 804                 if (*ok)        s->init_num = frag_len;
 805                 return frag_len;
 806                 }
 807
 808         /* read handshake message header */
 809         i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,wire,
 810                 DTLS1_HM_HEADER_LENGTH, 0);
 811         if (i <= 0)     /* nbio, or an error */
 812                 {
 813                 s->rwstate=SSL_READING;
 814                 *ok = 0;
 815                 return i;
 816                 }
 817         /* Handshake fails if message header is incomplete */
 818         if (i != DTLS1_HM_HEADER_LENGTH)
 819                 {
 820                 al=SSL_AD_UNEXPECTED_MESSAGE;
 821                 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
 822                 goto f_err;
 823                 }
 824
 825         /* parse the message fragment header */
 826         dtls1_get_message_header(wire, &msg_hdr);
 827
 828         /*
 829          * if this is a future (or stale) message it gets buffered
 830          * (or dropped)--no further processing at this time
 831          * While listening, we accept seq 1 (ClientHello with cookie)
 832          * although we're still expecting seq 0 (ClientHello)
 833          */
 834         if (msg_hdr.seq != s->d1->handshake_read_seq && !(s->d1->listen && msg_hdr.seq == 1))
 835                 return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
 836
 837         len = msg_hdr.msg_len;
 838         frag_off = msg_hdr.frag_off;
 839         frag_len = msg_hdr.frag_len;
 840
 841         if (frag_len && frag_len < len)
 842                 return dtls1_reassemble_fragment(s, &msg_hdr, ok);
 843
 844         if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
 845                 wire[0] == SSL3_MT_HELLO_REQUEST)
 846                 {
 847                 /* The server may always send 'Hello Request' messages --
 848                  * we are doing a handshake anyway now, so ignore them
 849                  * if their format is correct. Does not count for
 850                  * 'Finished' MAC. */
 851                 if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0)
 852                         {
 853                         if (s->msg_callback)
 854                                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 855                                         wire, DTLS1_HM_HEADER_LENGTH, s,
 856                                         s->msg_callback_arg);
 857
 858                         s->init_num = 0;
 859                         goto redo;
 860                         }
 861                 else /* Incorrectly formated Hello request */
 862                         {
 863                         al=SSL_AD_UNEXPECTED_MESSAGE;
 864                         SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
 865                         goto f_err;
 866                         }
 867                 }
 868
 869         if ((al=dtls1_preprocess_fragment(s,&msg_hdr,max)))
 870                 goto f_err;
 871
 872         /* XDTLS:  ressurect this when restart is in place */
 873         s->state=stn;
 874
 875         if ( frag_len > 0)
 876                 {
 877                 unsigned char *p=(unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
 878
 879                 i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 880                         &p[frag_off],frag_len,0);
 881                 /* XDTLS:  fix this--message fragments cannot span multiple packets */
 882                 if (i <= 0)
 883                         {
 884                         s->rwstate=SSL_READING;
 885                         *ok = 0;
 886                         return i;
 887                         }
 888                 }
 889         else
 890                 i = 0;
 891
 892         /* XDTLS:  an incorrectly formatted fragment should cause the
 893          * handshake to fail */
 894         if (i != (int)frag_len)
 895                 {
 896                 al=SSL3_AD_ILLEGAL_PARAMETER;
 897                 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL3_AD_ILLEGAL_PARAMETER);
 898                 goto f_err;
 899                 }
 900
 901         *ok = 1;
 902
 903         /* Note that s->init_num is *not* used as current offset in
 904          * s->init_buf->data, but as a counter summing up fragments'
 905          * lengths: as soon as they sum up to handshake packet
 906          * length, we assume we have got all the fragments. */
 907         s->init_num = frag_len;
 908         return frag_len;
 909
 910 f_err:
 911         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 912         s->init_num = 0;
 913
 914         *ok=0;
 915         return(-1);
 916         }
 917
 918 /* for these 2 messages, we need to
 919  * ssl->enc_read_ctx                    re-init
 920  * ssl->s3->read_sequence               zero
 921  * ssl->s3->read_mac_secret             re-init
 922  * ssl->session->read_sym_enc           assign
 923  * ssl->session->read_compression       assign
 924  * ssl->session->read_hash              assign
 925  */
 926 int dtls1_send_change_cipher_spec(SSL *s, int a, int b)
 927         {
 928         unsigned char *p;
 929
 930         if (s->state == a)
 931                 {
 932                 p=(unsigned char *)s->init_buf->data;
 933                 *p++=SSL3_MT_CCS;
 934                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
 935                 s->init_num=DTLS1_CCS_HEADER_LENGTH;
 936
 937                 if (s->version == DTLS1_BAD_VER) {
 938                         s->d1->next_handshake_write_seq++;
 939                         s2n(s->d1->handshake_write_seq,p);
 940                         s->init_num+=2;
 941                 }
 942
 943                 s->init_off=0;
 944
 945                 dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
 946                         s->d1->handshake_write_seq, 0, 0);
 947
 948                 /* buffer the message to handle re-xmits */
 949                 dtls1_buffer_message(s, 1);
 950
 951                 s->state=b;
 952                 }
 953
 954         /* SSL3_ST_CW_CHANGE_B */
 955         return(dtls1_do_write(s,SSL3_RT_CHANGE_CIPHER_SPEC));
 956         }
 957
 958 int dtls1_read_failed(SSL *s, int code)
 959         {
 960         if ( code > 0)
 961                 {
 962                 fprintf( stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
 963                 return 1;
 964                 }
 965
 966         if (!dtls1_is_timer_expired(s))
 967                 {
 968                 /* not a timeout, none of our business,
 969                    let higher layers handle this.  in fact it's probably an error */
 970                 return code;
 971                 }
 972
 973 #ifndef OPENSSL_NO_HEARTBEATS
 974         if (!SSL_in_init(s) && !s->tlsext_hb_pending)  /* done, no need to send a retransmit */
 975 #else
 976         if (!SSL_in_init(s))  /* done, no need to send a retransmit */
 977 #endif
 978                 {
 979                 BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
 980                 return code;
 981                 }
 982
 983 #if 0 /* for now, each alert contains only one record number */
 984         item = pqueue_peek(state->rcvd_records);
 985         if ( item )
 986                 {
 987                 /* send an alert immediately for all the missing records */
 988                 }
 989         else
 990 #endif
 991
 992 #if 0  /* no more alert sending, just retransmit the last set of messages */
 993         if ( state->timeout.read_timeouts >= DTLS1_TMO_READ_COUNT)
 994                 ssl3_send_alert(s,SSL3_AL_WARNING,
 995                         DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
 996 #endif
 997
 998         return dtls1_handle_timeout(s);
 999         }
1000
1001 int
1002 dtls1_get_queue_priority(unsigned short seq, int is_ccs)
1003         {
1004         /* The index of the retransmission queue actually is the message sequence number,
1005          * since the queue only contains messages of a single handshake. However, the
1006          * ChangeCipherSpec has no message sequence number and so using only the sequence
1007          * will result in the CCS and Finished having the same index. To prevent this,
1008          * the sequence number is multiplied by 2. In case of a CCS 1 is subtracted.
1009          * This does not only differ CSS and Finished, it also maintains the order of the
1010          * index (important for priority queues) and fits in the unsigned short variable.
1011          */
1012         return seq * 2 - is_ccs;
1013         }
1014
1015 int
1016 dtls1_retransmit_buffered_messages(SSL *s)
1017         {
1018         pqueue sent = s->d1->sent_messages;
1019         piterator iter;
1020         pitem *item;
1021         hm_fragment *frag;
1022         int found = 0;
1023
1024         iter = pqueue_iterator(sent);
1025
1026         for ( item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter))
1027                 {
1028                 frag = (hm_fragment *)item->data;
1029                         if ( dtls1_retransmit_message(s,
1030                                 (unsigned short)dtls1_get_queue_priority(frag->msg_header.seq, frag->msg_header.is_ccs),
1031                                 0, &found) <= 0 && found)
1032                         {
1033                         fprintf(stderr, "dtls1_retransmit_message() failed\n");
1034                         return -1;
1035                         }
1036                 }
1037
1038         return 1;
1039         }
1040
1041 int
1042 dtls1_buffer_message(SSL *s, int is_ccs)
1043         {
1044         pitem *item;
1045         hm_fragment *frag;
1046         unsigned char seq64be[8];
1047
1048         /* this function is called immediately after a message has
1049          * been serialized */
1050         OPENSSL_assert(s->init_off == 0);
1051
1052         frag = dtls1_hm_fragment_new(s->init_num, 0);
1053         if (!frag)
1054                 return 0;
1055
1056         memcpy(frag->fragment, s->init_buf->data, s->init_num);
1057
1058         if ( is_ccs)
1059                 {
1060                 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1061                                DTLS1_CCS_HEADER_LENGTH == (unsigned int)s->init_num);
1062                 }
1063         else
1064                 {
1065                 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1066                         DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num);
1067                 }
1068
1069         frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
1070         frag->msg_header.seq = s->d1->w_msg_hdr.seq;
1071         frag->msg_header.type = s->d1->w_msg_hdr.type;
1072         frag->msg_header.frag_off = 0;
1073         frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
1074         frag->msg_header.is_ccs = is_ccs;
1075
1076         /* save current state*/
1077         frag->msg_header.saved_retransmit_state.enc_write_ctx = s->enc_write_ctx;
1078         frag->msg_header.saved_retransmit_state.write_hash = s->write_hash;
1079         frag->msg_header.saved_retransmit_state.compress = s->compress;
1080         frag->msg_header.saved_retransmit_state.session = s->session;
1081         frag->msg_header.saved_retransmit_state.epoch = s->d1->w_epoch;
1082
1083         memset(seq64be,0,sizeof(seq64be));
1084         seq64be[6] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1085                                                                                                                   frag->msg_header.is_ccs)>>8);
1086         seq64be[7] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1087                                                                                                                   frag->msg_header.is_ccs));
1088
1089         item = pitem_new(seq64be, frag);
1090         if ( item == NULL)
1091                 {
1092                 dtls1_hm_fragment_free(frag);
1093                 return 0;
1094                 }
1095
1096 #if 0
1097         fprintf( stderr, "buffered messge: \ttype = %xx\n", msg_buf->type);
1098         fprintf( stderr, "\t\t\t\t\tlen = %d\n", msg_buf->len);
1099         fprintf( stderr, "\t\t\t\t\tseq_num = %d\n", msg_buf->seq_num);
1100 #endif
1101
1102         pqueue_insert(s->d1->sent_messages, item);
1103         return 1;
1104         }
1105
1106 int
1107 dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
1108         int *found)
1109         {
1110         int ret;
1111         /* XDTLS: for now assuming that read/writes are blocking */
1112         pitem *item;
1113         hm_fragment *frag ;
1114         unsigned long header_length;
1115         unsigned char seq64be[8];
1116         struct dtls1_retransmit_state saved_state;
1117         unsigned char save_write_sequence[8];
1118
1119         /*
1120           OPENSSL_assert(s->init_num == 0);
1121           OPENSSL_assert(s->init_off == 0);
1122          */
1123
1124         /* XDTLS:  the requested message ought to be found, otherwise error */
1125         memset(seq64be,0,sizeof(seq64be));
1126         seq64be[6] = (unsigned char)(seq>>8);
1127         seq64be[7] = (unsigned char)seq;
1128
1129         item = pqueue_find(s->d1->sent_messages, seq64be);
1130         if ( item == NULL)
1131                 {
1132                 fprintf(stderr, "retransmit:  message %d non-existant\n", seq);
1133                 *found = 0;
1134                 return 0;
1135                 }
1136
1137         *found = 1;
1138         frag = (hm_fragment *)item->data;
1139
1140         if ( frag->msg_header.is_ccs)
1141                 header_length = DTLS1_CCS_HEADER_LENGTH;
1142         else
1143                 header_length = DTLS1_HM_HEADER_LENGTH;
1144
1145         memcpy(s->init_buf->data, frag->fragment,
1146                 frag->msg_header.msg_len + header_length);
1147                 s->init_num = frag->msg_header.msg_len + header_length;
1148
1149         dtls1_set_message_header_int(s, frag->msg_header.type,
1150                 frag->msg_header.msg_len, frag->msg_header.seq, 0,
1151                 frag->msg_header.frag_len);
1152
1153         /* save current state */
1154         saved_state.enc_write_ctx = s->enc_write_ctx;
1155         saved_state.write_hash = s->write_hash;
1156         saved_state.compress = s->compress;
1157         saved_state.session = s->session;
1158         saved_state.epoch = s->d1->w_epoch;
1159         saved_state.epoch = s->d1->w_epoch;
1160
1161         s->d1->retransmitting = 1;
1162
1163         /* restore state in which the message was originally sent */
1164         s->enc_write_ctx = frag->msg_header.saved_retransmit_state.enc_write_ctx;
1165         s->write_hash = frag->msg_header.saved_retransmit_state.write_hash;
1166         s->compress = frag->msg_header.saved_retransmit_state.compress;
1167         s->session = frag->msg_header.saved_retransmit_state.session;
1168         s->d1->w_epoch = frag->msg_header.saved_retransmit_state.epoch;
1169
1170         if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1171         {
1172                 memcpy(save_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1173                 memcpy(s->s3->write_sequence, s->d1->last_write_sequence, sizeof(s->s3->write_sequence));
1174         }
1175
1176         ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1177                                                  SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1178
1179         /* restore current state */
1180         s->enc_write_ctx = saved_state.enc_write_ctx;
1181         s->write_hash = saved_state.write_hash;
1182         s->compress = saved_state.compress;
1183         s->session = saved_state.session;
1184         s->d1->w_epoch = saved_state.epoch;
1185
1186         if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1187         {
1188                 memcpy(s->d1->last_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1189                 memcpy(s->s3->write_sequence, save_write_sequence, sizeof(s->s3->write_sequence));
1190         }
1191
1192         s->d1->retransmitting = 0;
1193
1194         (void)BIO_flush(SSL_get_wbio(s));
1195         return ret;
1196         }
1197
1198 /* call this function when the buffered messages are no longer needed */
1199 void
1200 dtls1_clear_record_buffer(SSL *s)
1201         {
1202         pitem *item;
1203
1204         for(item = pqueue_pop(s->d1->sent_messages);
1205                 item != NULL; item = pqueue_pop(s->d1->sent_messages))
1206                 {
1207                 dtls1_hm_fragment_free((hm_fragment *)item->data);
1208                 pitem_free(item);
1209                 }
1210         }
1211
1212
1213 unsigned char *
1214 dtls1_set_message_header(SSL *s, unsigned char *p, unsigned char mt,
1215                         unsigned long len, unsigned long frag_off, unsigned long frag_len)
1216         {
1217         /* Don't change sequence numbers while listening */
1218         if (frag_off == 0 && !s->d1->listen)
1219                 {
1220                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1221                 s->d1->next_handshake_write_seq++;
1222                 }
1223
1224         dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1225                 frag_off, frag_len);
1226
1227         return p += DTLS1_HM_HEADER_LENGTH;
1228         }
1229
1230
1231 /* don't actually do the writing, wait till the MTU has been retrieved */
1232 static void
1233 dtls1_set_message_header_int(SSL *s, unsigned char mt,
1234                             unsigned long len, unsigned short seq_num, unsigned long frag_off,
1235                             unsigned long frag_len)
1236         {
1237         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1238
1239         msg_hdr->type = mt;
1240         msg_hdr->msg_len = len;
1241         msg_hdr->seq = seq_num;
1242         msg_hdr->frag_off = frag_off;
1243         msg_hdr->frag_len = frag_len;
1244         }
1245
1246 static void
1247 dtls1_fix_message_header(SSL *s, unsigned long frag_off,
1248                         unsigned long frag_len)
1249         {
1250         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1251
1252         msg_hdr->frag_off = frag_off;
1253         msg_hdr->frag_len = frag_len;
1254         }
1255
1256 static unsigned char *
1257 dtls1_write_message_header(SSL *s, unsigned char *p)
1258         {
1259         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1260
1261         *p++ = msg_hdr->type;
1262         l2n3(msg_hdr->msg_len, p);
1263
1264         s2n(msg_hdr->seq, p);
1265         l2n3(msg_hdr->frag_off, p);
1266         l2n3(msg_hdr->frag_len, p);
1267
1268         return p;
1269         }
1270
1271 unsigned int
1272 dtls1_min_mtu(void)
1273         {
1274         return (g_probable_mtu[(sizeof(g_probable_mtu) /
1275                 sizeof(g_probable_mtu[0])) - 1]);
1276         }
1277
1278 static unsigned int
1279 dtls1_guess_mtu(unsigned int curr_mtu)
1280         {
1281         unsigned int i;
1282
1283         if ( curr_mtu == 0 )
1284                 return g_probable_mtu[0] ;
1285
1286         for ( i = 0; i < sizeof(g_probable_mtu)/sizeof(g_probable_mtu[0]); i++)
1287                 if ( curr_mtu > g_probable_mtu[i])
1288                         return g_probable_mtu[i];
1289
1290         return curr_mtu;
1291         }
1292
1293 void
1294 dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
1295         {
1296         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
1297         msg_hdr->type = *(data++);
1298         n2l3(data, msg_hdr->msg_len);
1299
1300         n2s(data, msg_hdr->seq);
1301         n2l3(data, msg_hdr->frag_off);
1302         n2l3(data, msg_hdr->frag_len);
1303         }
1304
1305 void
1306 dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st *ccs_hdr)
1307         {
1308         memset(ccs_hdr, 0x00, sizeof(struct ccs_header_st));
1309
1310         ccs_hdr->type = *(data++);
1311         }
1312
1313 int dtls1_shutdown(SSL *s)
1314         {
1315         int ret;
1316 #ifndef OPENSSL_NO_SCTP
1317         if (BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
1318             !(s->shutdown & SSL_SENT_SHUTDOWN))
1319                 {
1320                 ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
1321                 if (ret < 0) return -1;
1322
1323                 if (ret == 0)
1324                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1, NULL);
1325                 }
1326 #endif
1327         ret = ssl3_shutdown(s);
1328 #ifndef OPENSSL_NO_SCTP
1329         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
1330 #endif
1331         return ret;
1332         }
1333
1334 #ifndef OPENSSL_NO_HEARTBEATS
1335 int
1336 dtls1_process_heartbeat(SSL *s)
1337         {
1338         unsigned char *p = &s->s3->rrec.data[0], *pl;
1339         unsigned short hbtype;
1340         unsigned int payload;
1341         unsigned int padding = 16; /* Use minimum padding */
1342
1343         if (s->msg_callback)
1344                 s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
1345                         &s->s3->rrec.data[0], s->s3->rrec.length,
1346                         s, s->msg_callback_arg);
1347
1348         /* Read type and payload length first */
1349         if (1 + 2 + 16 > s->s3->rrec.length)
1350                 return 0; /* silently discard */
1351         hbtype = *p++;
1352         n2s(p, payload);
1353         if (1 + 2 + payload + 16 > s->s3->rrec.length)
1354                 return 0; /* silently discard per RFC 6520 sec. 4 */
1355         pl = p;
1356
1357         if (hbtype == TLS1_HB_REQUEST)
1358                 {
1359                 unsigned char *buffer, *bp;
1360                 unsigned int write_length = 1 /* heartbeat type */ +
1361                                             2 /* heartbeat length */ +
1362                                             payload + padding;
1363                 int r;
1364
1365                 if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
1366                         return 0;
1367
1368                 /* Allocate memory for the response, size is 1 byte
1369                  * message type, plus 2 bytes payload length, plus
1370                  * payload, plus padding
1371                  */
1372                 buffer = OPENSSL_malloc(write_length);
1373                 bp = buffer;
1374
1375                 /* Enter response type, length and copy payload */
1376                 *bp++ = TLS1_HB_RESPONSE;
1377                 s2n(payload, bp);
1378                 memcpy(bp, pl, payload);
1379                 bp += payload;
1380                 /* Random padding */
1381                 RAND_pseudo_bytes(bp, padding);
1382
1383                 r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, write_length);
1384
1385                 if (r >= 0 && s->msg_callback)
1386                         s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1387                                 buffer, write_length,
1388                                 s, s->msg_callback_arg);
1389
1390                 OPENSSL_free(buffer);
1391
1392                 if (r < 0)
1393                         return r;
1394                 }
1395         else if (hbtype == TLS1_HB_RESPONSE)
1396                 {
1397                 unsigned int seq;
1398
1399                 /* We only send sequence numbers (2 bytes unsigned int),
1400                  * and 16 random bytes, so we just try to read the
1401                  * sequence number */
1402                 n2s(pl, seq);
1403
1404                 if (payload == 18 && seq == s->tlsext_hb_seq)
1405                         {
1406                         dtls1_stop_timer(s);
1407                         s->tlsext_hb_seq++;
1408                         s->tlsext_hb_pending = 0;
1409                         }
1410                 }
1411
1412         return 0;
1413         }
1414
1415 int
1416 dtls1_heartbeat(SSL *s)
1417         {
1418         unsigned char *buf, *p;
1419         int ret;
1420         unsigned int payload = 18; /* Sequence number + random bytes */
1421         unsigned int padding = 16; /* Use minimum padding */
1422
1423         /* Only send if peer supports and accepts HB requests... */
1424         if (!(s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED) ||
1425             s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS)
1426                 {
1427                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
1428                 return -1;
1429                 }
1430
1431         /* ...and there is none in flight yet... */
1432         if (s->tlsext_hb_pending)
1433                 {
1434                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PENDING);
1435                 return -1;
1436                 }
1437
1438         /* ...and no handshake in progress. */
1439         if (SSL_in_init(s) || s->in_handshake)
1440                 {
1441                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_UNEXPECTED_MESSAGE);
1442                 return -1;
1443                 }
1444
1445         /* Check if padding is too long, payload and padding
1446          * must not exceed 2^14 - 3 = 16381 bytes in total.
1447          */
1448         OPENSSL_assert(payload + padding <= 16381);
1449
1450         /* Create HeartBeat message, we just use a sequence number
1451          * as payload to distuingish different messages and add
1452          * some random stuff.
1453          *  - Message Type, 1 byte
1454          *  - Payload Length, 2 bytes (unsigned int)
1455          *  - Payload, the sequence number (2 bytes uint)
1456          *  - Payload, random bytes (16 bytes uint)
1457          *  - Padding
1458          */
1459         buf = OPENSSL_malloc(1 + 2 + payload + padding);
1460         p = buf;
1461         /* Message Type */
1462         *p++ = TLS1_HB_REQUEST;
1463         /* Payload length (18 bytes here) */
1464         s2n(payload, p);
1465         /* Sequence number */
1466         s2n(s->tlsext_hb_seq, p);
1467         /* 16 random bytes */
1468         RAND_pseudo_bytes(p, 16);
1469         p += 16;
1470         /* Random padding */
1471         RAND_pseudo_bytes(p, padding);
1472
1473         ret = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buf, 3 + payload + padding);
1474         if (ret >= 0)
1475                 {
1476                 if (s->msg_callback)
1477                         s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1478                                 buf, 3 + payload + padding,
1479                                 s, s->msg_callback_arg);
1480
1481                 dtls1_start_timer(s);
1482                 s->tlsext_hb_pending = 1;
1483                 }
1484
1485         OPENSSL_free(buf);
1486
1487         return ret;
1488         }
1489 #endif