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 void dtls1_hm_fragment_free(hm_fragment *frag)
 215         {
 216
 217         if (frag->msg_header.is_ccs)
 218                 {
 219                 EVP_CIPHER_CTX_free(frag->msg_header.saved_retransmit_state.enc_write_ctx);
 220                 EVP_MD_CTX_destroy(frag->msg_header.saved_retransmit_state.write_hash);
 221                 }
 222         if (frag->fragment) OPENSSL_free(frag->fragment);
 223         if (frag->reassembly) OPENSSL_free(frag->reassembly);
 224         OPENSSL_free(frag);
 225         }
 226
 227 static void dtls1_query_mtu(SSL *s)
 228 {
 229         /* AHA!  Figure out the MTU, and stick to the right size */
 230         if (s->d1->mtu < dtls1_min_mtu() && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))
 231                 {
 232                 s->d1->mtu =
 233                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
 234
 235                 /* I've seen the kernel return bogus numbers when it doesn't know
 236                  * (initial write), so just make sure we have a reasonable number */
 237                 if (s->d1->mtu < dtls1_min_mtu())
 238                         {
 239                         s->d1->mtu = 0;
 240                         s->d1->mtu = dtls1_guess_mtu(s->d1->mtu);
 241                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
 242                                 s->d1->mtu, NULL);
 243                         }
 244                 }
 245 }
 246
 247 /* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */
 248 int dtls1_do_write(SSL *s, int type)
 249         {
 250         int ret;
 251         int curr_mtu;
 252         unsigned int len, frag_off, mac_size, blocksize;
 253
 254         dtls1_query_mtu(s);
 255 #if 0
 256         mtu = s->d1->mtu;
 257
 258         fprintf(stderr, "using MTU = %d\n", mtu);
 259
 260         mtu -= (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
 261
 262         curr_mtu = mtu - BIO_wpending(SSL_get_wbio(s));
 263
 264         if ( curr_mtu > 0)
 265                 mtu = curr_mtu;
 266         else if ( ( ret = BIO_flush(SSL_get_wbio(s))) <= 0)
 267                 return ret;
 268
 269         if ( BIO_wpending(SSL_get_wbio(s)) + s->init_num >= mtu)
 270                 {
 271                 ret = BIO_flush(SSL_get_wbio(s));
 272                 if ( ret <= 0)
 273                         return ret;
 274                 mtu = s->d1->mtu - (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
 275                 }
 276 #endif
 277
 278         OPENSSL_assert(s->d1->mtu >= dtls1_min_mtu());  /* should have something reasonable now */
 279
 280         if ( s->init_off == 0  && type == SSL3_RT_HANDSHAKE)
 281                 OPENSSL_assert(s->init_num ==
 282                         (int)s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH);
 283
 284         if (s->write_hash)
 285                 mac_size = EVP_MD_CTX_size(s->write_hash);
 286         else
 287                 mac_size = 0;
 288
 289         if (s->enc_write_ctx &&
 290                 (EVP_CIPHER_mode( s->enc_write_ctx->cipher) & EVP_CIPH_CBC_MODE))
 291                 blocksize = 2 * EVP_CIPHER_block_size(s->enc_write_ctx->cipher);
 292         else
 293                 blocksize = 0;
 294
 295         frag_off = 0;
 296         while( s->init_num)
 297                 {
 298                 curr_mtu = s->d1->mtu - BIO_wpending(SSL_get_wbio(s)) -
 299                         DTLS1_RT_HEADER_LENGTH - mac_size - blocksize;
 300
 301                 if ( curr_mtu <= DTLS1_HM_HEADER_LENGTH)
 302                         {
 303                         /* grr.. we could get an error if MTU picked was wrong */
 304                         ret = BIO_flush(SSL_get_wbio(s));
 305                         if ( ret <= 0)
 306                                 return ret;
 307                         curr_mtu = s->d1->mtu - DTLS1_RT_HEADER_LENGTH -
 308                                 mac_size - blocksize;
 309                         }
 310
 311                 if ( s->init_num > curr_mtu)
 312                         len = curr_mtu;
 313                 else
 314                         len = s->init_num;
 315
 316
 317                 /* XDTLS: this function is too long.  split out the CCS part */
 318                 if ( type == SSL3_RT_HANDSHAKE)
 319                         {
 320                         if ( s->init_off != 0)
 321                                 {
 322                                 OPENSSL_assert(s->init_off > DTLS1_HM_HEADER_LENGTH);
 323                                 s->init_off -= DTLS1_HM_HEADER_LENGTH;
 324                                 s->init_num += DTLS1_HM_HEADER_LENGTH;
 325
 326                                 if ( s->init_num > curr_mtu)
 327                                         len = curr_mtu;
 328                                 else
 329                                         len = s->init_num;
 330                                 }
 331
 332                         if ( len < DTLS1_HM_HEADER_LENGTH )
 333                                 {
 334                                 /*
 335                                  * len is so small that we really can't do anything sensible
 336                                  * so fail
 337                                  */
 338                                 return -1;
 339                                 }
 340                         dtls1_fix_message_header(s, frag_off,
 341                                 len - DTLS1_HM_HEADER_LENGTH);
 342
 343                         dtls1_write_message_header(s, (unsigned char *)&s->init_buf->data[s->init_off]);
 344                         }
 345
 346                 ret=dtls1_write_bytes(s,type,&s->init_buf->data[s->init_off],
 347                         len);
 348                 if (ret < 0)
 349                         {
 350                         /* might need to update MTU here, but we don't know
 351                          * which previous packet caused the failure -- so can't
 352                          * really retransmit anything.  continue as if everything
 353                          * is fine and wait for an alert to handle the
 354                          * retransmit
 355                          */
 356                         if ( BIO_ctrl(SSL_get_wbio(s),
 357                                 BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0 )
 358                                 {
 359                                 if(!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))
 360                                         dtls1_query_mtu(s);
 361                                 else
 362                                         return -1;
 363                                 }
 364                         else
 365                                 {
 366                                 return(-1);
 367                                 }
 368                         }
 369                 else
 370                         {
 371
 372                         /* bad if this assert fails, only part of the handshake
 373                          * message got sent.  but why would this happen? */
 374                         OPENSSL_assert(len == (unsigned int)ret);
 375
 376                         if (type == SSL3_RT_HANDSHAKE && ! s->d1->retransmitting)
 377                                 {
 378                                 /* should not be done for 'Hello Request's, but in that case
 379                                  * we'll ignore the result anyway */
 380                                 unsigned char *p = (unsigned char *)&s->init_buf->data[s->init_off];
 381                                 const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
 382                                 int xlen;
 383
 384                                 if (frag_off == 0 && s->version != DTLS1_BAD_VER)
 385                                         {
 386                                         /* reconstruct message header is if it
 387                                          * is being sent in single fragment */
 388                                         *p++ = msg_hdr->type;
 389                                         l2n3(msg_hdr->msg_len,p);
 390                                         s2n (msg_hdr->seq,p);
 391                                         l2n3(0,p);
 392                                         l2n3(msg_hdr->msg_len,p);
 393                                         p  -= DTLS1_HM_HEADER_LENGTH;
 394                                         xlen = ret;
 395                                         }
 396                                 else
 397                                         {
 398                                         p  += DTLS1_HM_HEADER_LENGTH;
 399                                         xlen = ret - DTLS1_HM_HEADER_LENGTH;
 400                                         }
 401
 402                                 ssl3_finish_mac(s, p, xlen);
 403                                 }
 404
 405                         if (ret == s->init_num)
 406                                 {
 407                                 if (s->msg_callback)
 408                                         s->msg_callback(1, s->version, type, s->init_buf->data,
 409                                                 (size_t)(s->init_off + s->init_num), s,
 410                                                 s->msg_callback_arg);
 411
 412                                 s->init_off = 0;  /* done writing this message */
 413                                 s->init_num = 0;
 414
 415                                 return(1);
 416                                 }
 417                         s->init_off+=ret;
 418                         s->init_num-=ret;
 419                         frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
 420                         }
 421                 }
 422         return(0);
 423         }
 424
 425
 426 /* Obtain handshake message of message type 'mt' (any if mt == -1),
 427  * maximum acceptable body length 'max'.
 428  * Read an entire handshake message.  Handshake messages arrive in
 429  * fragments.
 430  */
 431 long dtls1_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
 432         {
 433         int i, al;
 434         struct hm_header_st *msg_hdr;
 435         unsigned char *p;
 436         unsigned long msg_len;
 437
 438         /* s3->tmp is used to store messages that are unexpected, caused
 439          * by the absence of an optional handshake message */
 440         if (s->s3->tmp.reuse_message)
 441                 {
 442                 s->s3->tmp.reuse_message=0;
 443                 if ((mt >= 0) && (s->s3->tmp.message_type != mt))
 444                         {
 445                         al=SSL_AD_UNEXPECTED_MESSAGE;
 446                         SSLerr(SSL_F_DTLS1_GET_MESSAGE,SSL_R_UNEXPECTED_MESSAGE);
 447                         goto f_err;
 448                         }
 449                 *ok=1;
 450                 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 451                 s->init_num = (int)s->s3->tmp.message_size;
 452                 return s->init_num;
 453                 }
 454
 455         msg_hdr = &s->d1->r_msg_hdr;
 456         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
 457
 458 again:
 459         i = dtls1_get_message_fragment(s, st1, stn, max, ok);
 460         if ( i == DTLS1_HM_BAD_FRAGMENT ||
 461                 i == DTLS1_HM_FRAGMENT_RETRY)  /* bad fragment received */
 462                 goto again;
 463         else if ( i <= 0 && !*ok)
 464                 return i;
 465
 466         p = (unsigned char *)s->init_buf->data;
 467         msg_len = msg_hdr->msg_len;
 468
 469         /* reconstruct message header */
 470         *(p++) = msg_hdr->type;
 471         l2n3(msg_len,p);
 472         s2n (msg_hdr->seq,p);
 473         l2n3(0,p);
 474         l2n3(msg_len,p);
 475         if (s->version != DTLS1_BAD_VER) {
 476                 p       -= DTLS1_HM_HEADER_LENGTH;
 477                 msg_len += DTLS1_HM_HEADER_LENGTH;
 478         }
 479
 480         ssl3_finish_mac(s, p, msg_len);
 481         if (s->msg_callback)
 482                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 483                         p, msg_len,
 484                         s, s->msg_callback_arg);
 485
 486         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
 487
 488         /* Don't change sequence numbers while listening */
 489         if (!s->d1->listen)
 490                 s->d1->handshake_read_seq++;
 491
 492         s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 493         return s->init_num;
 494
 495 f_err:
 496         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 497         *ok = 0;
 498         return -1;
 499         }
 500
 501
 502 static int dtls1_preprocess_fragment(SSL *s,struct hm_header_st *msg_hdr,int max)
 503         {
 504         size_t frag_off,frag_len,msg_len;
 505
 506         msg_len  = msg_hdr->msg_len;
 507         frag_off = msg_hdr->frag_off;
 508         frag_len = msg_hdr->frag_len;
 509
 510         /* sanity checking */
 511         if ( (frag_off+frag_len) > msg_len)
 512                 {
 513                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 514                 return SSL_AD_ILLEGAL_PARAMETER;
 515                 }
 516
 517         if ( (frag_off+frag_len) > (unsigned long)max)
 518                 {
 519                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 520                 return SSL_AD_ILLEGAL_PARAMETER;
 521                 }
 522
 523         if ( s->d1->r_msg_hdr.frag_off == 0) /* first fragment */
 524                 {
 525                 /* msg_len is limited to 2^24, but is effectively checked
 526                  * against max above */
 527                 if (!BUF_MEM_grow_clean(s->init_buf,msg_len+DTLS1_HM_HEADER_LENGTH))
 528                         {
 529                         SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,ERR_R_BUF_LIB);
 530                         return SSL_AD_INTERNAL_ERROR;
 531                         }
 532
 533                 s->s3->tmp.message_size  = msg_len;
 534                 s->d1->r_msg_hdr.msg_len = msg_len;
 535                 s->s3->tmp.message_type  = msg_hdr->type;
 536                 s->d1->r_msg_hdr.type    = msg_hdr->type;
 537                 s->d1->r_msg_hdr.seq     = msg_hdr->seq;
 538                 }
 539         else if (msg_len != s->d1->r_msg_hdr.msg_len)
 540                 {
 541                 /* They must be playing with us! BTW, failure to enforce
 542                  * upper limit would open possibility for buffer overrun. */
 543                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 544                 return SSL_AD_ILLEGAL_PARAMETER;
 545                 }
 546
 547         return 0; /* no error */
 548         }
 549
 550
 551 static int
 552 dtls1_retrieve_buffered_fragment(SSL *s, long max, int *ok)
 553         {
 554         /* (0) check whether the desired fragment is available
 555          * if so:
 556          * (1) copy over the fragment to s->init_buf->data[]
 557          * (2) update s->init_num
 558          */
 559         pitem *item;
 560         hm_fragment *frag;
 561         int al;
 562
 563         *ok = 0;
 564         item = pqueue_peek(s->d1->buffered_messages);
 565         if ( item == NULL)
 566                 return 0;
 567
 568         frag = (hm_fragment *)item->data;
 569
 570         /* Don't return if reassembly still in progress */
 571         if (frag->reassembly != NULL)
 572                 return 0;
 573
 574         if ( s->d1->handshake_read_seq == frag->msg_header.seq)
 575                 {
 576                 unsigned long frag_len = frag->msg_header.frag_len;
 577                 pqueue_pop(s->d1->buffered_messages);
 578
 579                 al=dtls1_preprocess_fragment(s,&frag->msg_header,max);
 580
 581                 if (al==0) /* no alert */
 582                         {
 583                         unsigned char *p = (unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
 584                         memcpy(&p[frag->msg_header.frag_off],
 585                                 frag->fragment,frag->msg_header.frag_len);
 586                         }
 587
 588                 dtls1_hm_fragment_free(frag);
 589                 pitem_free(item);
 590
 591                 if (al==0)
 592                         {
 593                         *ok = 1;
 594                         return frag_len;
 595                         }
 596
 597                 ssl3_send_alert(s,SSL3_AL_FATAL,al);
 598                 s->init_num = 0;
 599                 *ok = 0;
 600                 return -1;
 601                 }
 602         else
 603                 return 0;
 604         }
 605
 606 /* dtls1_max_handshake_message_len returns the maximum number of bytes
 607  * permitted in a DTLS handshake message for |s|. The minimum is 16KB, but may
 608  * be greater if the maximum certificate list size requires it. */
 609 static unsigned long dtls1_max_handshake_message_len(const SSL *s)
 610         {
 611         unsigned long max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
 612         if (max_len < (unsigned long)s->max_cert_list)
 613                 return s->max_cert_list;
 614         return max_len;
 615         }
 616
 617 static int
 618 dtls1_reassemble_fragment(SSL *s, const struct hm_header_st* msg_hdr, int *ok)
 619         {
 620         hm_fragment *frag = NULL;
 621         pitem *item = NULL;
 622         int i = -1, is_complete;
 623         unsigned char seq64be[8];
 624         unsigned long frag_len = msg_hdr->frag_len;
 625
 626         if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len ||
 627             msg_hdr->msg_len > dtls1_max_handshake_message_len(s))
 628                 goto err;
 629
 630         if (frag_len == 0)
 631                 return DTLS1_HM_FRAGMENT_RETRY;
 632
 633         /* Try to find item in queue */
 634         memset(seq64be,0,sizeof(seq64be));
 635         seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
 636         seq64be[7] = (unsigned char) msg_hdr->seq;
 637         item = pqueue_find(s->d1->buffered_messages, seq64be);
 638
 639         if (item == NULL)
 640                 {
 641                 frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1);
 642                 if ( frag == NULL)
 643                         goto err;
 644                 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
 645                 frag->msg_header.frag_len = frag->msg_header.msg_len;
 646                 frag->msg_header.frag_off = 0;
 647                 }
 648         else
 649                 {
 650                 frag = (hm_fragment*) item->data;
 651                 if (frag->msg_header.msg_len != msg_hdr->msg_len)
 652                         {
 653                         item = NULL;
 654                         frag = NULL;
 655                         goto err;
 656                         }
 657                 }
 658
 659
 660         /* If message is already reassembled, this must be a
 661          * retransmit and can be dropped. In this case item != NULL and so frag
 662          * does not need to be freed.
 663          */
 664         if (frag->reassembly == NULL)
 665                 {
 666                 unsigned char devnull [256];
 667
 668                 while (frag_len)
 669                         {
 670                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 671                                 devnull,
 672                                 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
 673                         if (i<=0) goto err;
 674                         frag_len -= i;
 675                         }
 676                 return DTLS1_HM_FRAGMENT_RETRY;
 677                 }
 678
 679         /* read the body of the fragment (header has already been read */
 680         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 681                 frag->fragment + msg_hdr->frag_off,frag_len,0);
 682         if ((unsigned long)i!=frag_len)
 683                 i=-1;
 684         if (i<=0)
 685                 goto err;
 686
 687         RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off,
 688                             (long)(msg_hdr->frag_off + frag_len));
 689
 690         RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len,
 691                                    is_complete);
 692
 693         if (is_complete)
 694                 {
 695                 OPENSSL_free(frag->reassembly);
 696                 frag->reassembly = NULL;
 697                 }
 698
 699         if (item == NULL)
 700                 {
 701                 item = pitem_new(seq64be, frag);
 702                 if (item == NULL)
 703                         {
 704                         i = -1;
 705                         goto err;
 706                         }
 707
 708                 item = pqueue_insert(s->d1->buffered_messages, item);
 709                 /* pqueue_insert fails iff a duplicate item is inserted.
 710                  * However, |item| cannot be a duplicate. If it were,
 711                  * |pqueue_find|, above, would have returned it and control
 712                  * would never have reached this branch. */
 713                 OPENSSL_assert(item != NULL);
 714                 }
 715
 716         return DTLS1_HM_FRAGMENT_RETRY;
 717
 718 err:
 719         if (frag != NULL && item == NULL) dtls1_hm_fragment_free(frag);
 720         *ok = 0;
 721         return i;
 722         }
 723
 724
 725 static int
 726 dtls1_process_out_of_seq_message(SSL *s, const struct hm_header_st* msg_hdr, int *ok)
 727 {
 728         int i=-1;
 729         hm_fragment *frag = NULL;
 730         pitem *item = NULL;
 731         unsigned char seq64be[8];
 732         unsigned long frag_len = msg_hdr->frag_len;
 733
 734         if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len)
 735                 goto err;
 736
 737         /* Try to find item in queue, to prevent duplicate entries */
 738         memset(seq64be,0,sizeof(seq64be));
 739         seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
 740         seq64be[7] = (unsigned char) msg_hdr->seq;
 741         item = pqueue_find(s->d1->buffered_messages, seq64be);
 742
 743         /* If we already have an entry and this one is a fragment,
 744          * don't discard it and rather try to reassemble it.
 745          */
 746         if (item != NULL && frag_len != msg_hdr->msg_len)
 747                 item = NULL;
 748
 749         /* Discard the message if sequence number was already there, is
 750          * too far in the future, already in the queue or if we received
 751          * a FINISHED before the SERVER_HELLO, which then must be a stale
 752          * retransmit.
 753          */
 754         if (msg_hdr->seq <= s->d1->handshake_read_seq ||
 755                 msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL ||
 756                 (s->d1->handshake_read_seq == 0 && msg_hdr->type == SSL3_MT_FINISHED))
 757                 {
 758                 unsigned char devnull [256];
 759
 760                 while (frag_len)
 761                         {
 762                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 763                                 devnull,
 764                                 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
 765                         if (i<=0) goto err;
 766                         frag_len -= i;
 767                         }
 768                 }
 769         else
 770                 {
 771                 if (frag_len != msg_hdr->msg_len)
 772                         return dtls1_reassemble_fragment(s, msg_hdr, ok);
 773
 774                 if (frag_len > dtls1_max_handshake_message_len(s))
 775                         goto err;
 776
 777                 frag = dtls1_hm_fragment_new(frag_len, 0);
 778                 if ( frag == NULL)
 779                         goto err;
 780
 781                 memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
 782
 783                 if (frag_len)
 784                         {
 785                         /* read the body of the fragment (header has already been read */
 786                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 787                                 frag->fragment,frag_len,0);
 788                         if ((unsigned long)i!=frag_len)
 789                                 i = -1;
 790                         if (i<=0)
 791                                 goto err;
 792                         }
 793
 794                 item = pitem_new(seq64be, frag);
 795                 if ( item == NULL)
 796                         goto err;
 797
 798                 item = pqueue_insert(s->d1->buffered_messages, item);
 799                 /* pqueue_insert fails iff a duplicate item is inserted.
 800                  * However, |item| cannot be a duplicate. If it were,
 801                  * |pqueue_find|, above, would have returned it. Then, either
 802                  * |frag_len| != |msg_hdr->msg_len| in which case |item| is set
 803                  * to NULL and it will have been processed with
 804                  * |dtls1_reassemble_fragment|, above, or the record will have
 805                  * been discarded. */
 806                 OPENSSL_assert(item != NULL);
 807                 }
 808
 809         return DTLS1_HM_FRAGMENT_RETRY;
 810
 811 err:
 812         if (frag != NULL && item == NULL) dtls1_hm_fragment_free(frag);
 813         *ok = 0;
 814         return i;
 815         }
 816
 817
 818 static long
 819 dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
 820         {
 821         unsigned char wire[DTLS1_HM_HEADER_LENGTH];
 822         unsigned long len, frag_off, frag_len;
 823         int i,al;
 824         struct hm_header_st msg_hdr;
 825
 826         redo:
 827         /* see if we have the required fragment already */
 828         if ((frag_len = dtls1_retrieve_buffered_fragment(s,max,ok)) || *ok)
 829                 {
 830                 if (*ok)        s->init_num = frag_len;
 831                 return frag_len;
 832                 }
 833
 834         /* read handshake message header */
 835         i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,wire,
 836                 DTLS1_HM_HEADER_LENGTH, 0);
 837         if (i <= 0)     /* nbio, or an error */
 838                 {
 839                 s->rwstate=SSL_READING;
 840                 *ok = 0;
 841                 return i;
 842                 }
 843         /* Handshake fails if message header is incomplete */
 844         if (i != DTLS1_HM_HEADER_LENGTH)
 845                 {
 846                 al=SSL_AD_UNEXPECTED_MESSAGE;
 847                 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
 848                 goto f_err;
 849                 }
 850
 851         /* parse the message fragment header */
 852         dtls1_get_message_header(wire, &msg_hdr);
 853
 854         /*
 855          * if this is a future (or stale) message it gets buffered
 856          * (or dropped)--no further processing at this time
 857          * While listening, we accept seq 1 (ClientHello with cookie)
 858          * although we're still expecting seq 0 (ClientHello)
 859          */
 860         if (msg_hdr.seq != s->d1->handshake_read_seq && !(s->d1->listen && msg_hdr.seq == 1))
 861                 return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
 862
 863         len = msg_hdr.msg_len;
 864         frag_off = msg_hdr.frag_off;
 865         frag_len = msg_hdr.frag_len;
 866
 867         if (frag_len && frag_len < len)
 868                 return dtls1_reassemble_fragment(s, &msg_hdr, ok);
 869
 870         if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
 871                 wire[0] == SSL3_MT_HELLO_REQUEST)
 872                 {
 873                 /* The server may always send 'Hello Request' messages --
 874                  * we are doing a handshake anyway now, so ignore them
 875                  * if their format is correct. Does not count for
 876                  * 'Finished' MAC. */
 877                 if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0)
 878                         {
 879                         if (s->msg_callback)
 880                                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 881                                         wire, DTLS1_HM_HEADER_LENGTH, s,
 882                                         s->msg_callback_arg);
 883
 884                         s->init_num = 0;
 885                         goto redo;
 886                         }
 887                 else /* Incorrectly formated Hello request */
 888                         {
 889                         al=SSL_AD_UNEXPECTED_MESSAGE;
 890                         SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
 891                         goto f_err;
 892                         }
 893                 }
 894
 895         if ((al=dtls1_preprocess_fragment(s,&msg_hdr,max)))
 896                 goto f_err;
 897
 898         /* XDTLS:  ressurect this when restart is in place */
 899         s->state=stn;
 900
 901         if ( frag_len > 0)
 902                 {
 903                 unsigned char *p=(unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
 904
 905                 i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 906                         &p[frag_off],frag_len,0);
 907                 /* XDTLS:  fix this--message fragments cannot span multiple packets */
 908                 if (i <= 0)
 909                         {
 910                         s->rwstate=SSL_READING;
 911                         *ok = 0;
 912                         return i;
 913                         }
 914                 }
 915         else
 916                 i = 0;
 917
 918         /* XDTLS:  an incorrectly formatted fragment should cause the
 919          * handshake to fail */
 920         if (i != (int)frag_len)
 921                 {
 922                 al=SSL3_AD_ILLEGAL_PARAMETER;
 923                 SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL3_AD_ILLEGAL_PARAMETER);
 924                 goto f_err;
 925                 }
 926
 927         *ok = 1;
 928
 929         /* Note that s->init_num is *not* used as current offset in
 930          * s->init_buf->data, but as a counter summing up fragments'
 931          * lengths: as soon as they sum up to handshake packet
 932          * length, we assume we have got all the fragments. */
 933         s->init_num = frag_len;
 934         return frag_len;
 935
 936 f_err:
 937         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 938         s->init_num = 0;
 939
 940         *ok=0;
 941         return(-1);
 942         }
 943
 944 int dtls1_send_finished(SSL *s, int a, int b, const char *sender, int slen)
 945         {
 946         unsigned char *p,*d;
 947         int i;
 948         unsigned long l;
 949
 950         if (s->state == a)
 951                 {
 952                 d=(unsigned char *)s->init_buf->data;
 953                 p= &(d[DTLS1_HM_HEADER_LENGTH]);
 954
 955                 i=s->method->ssl3_enc->final_finish_mac(s,
 956                         sender,slen,s->s3->tmp.finish_md);
 957                 s->s3->tmp.finish_md_len = i;
 958                 memcpy(p, s->s3->tmp.finish_md, i);
 959                 p+=i;
 960                 l=i;
 961
 962         /* Copy the finished so we can use it for
 963          * renegotiation checks
 964          */
 965         if(s->type == SSL_ST_CONNECT)
 966                 {
 967                 OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
 968                 memcpy(s->s3->previous_client_finished,
 969                        s->s3->tmp.finish_md, i);
 970                 s->s3->previous_client_finished_len=i;
 971                 }
 972         else
 973                 {
 974                 OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
 975                 memcpy(s->s3->previous_server_finished,
 976                        s->s3->tmp.finish_md, i);
 977                 s->s3->previous_server_finished_len=i;
 978                 }
 979
 980 #ifdef OPENSSL_SYS_WIN16
 981                 /* MSVC 1.5 does not clear the top bytes of the word unless
 982                  * I do this.
 983                  */
 984                 l&=0xffff;
 985 #endif
 986
 987                 d = dtls1_set_message_header(s, d, SSL3_MT_FINISHED, l, 0, l);
 988                 s->init_num=(int)l+DTLS1_HM_HEADER_LENGTH;
 989                 s->init_off=0;
 990
 991                 /* buffer the message to handle re-xmits */
 992                 dtls1_buffer_message(s, 0);
 993
 994                 s->state=b;
 995                 }
 996
 997         /* SSL3_ST_SEND_xxxxxx_HELLO_B */
 998         return(dtls1_do_write(s,SSL3_RT_HANDSHAKE));
 999         }
1000
1001 /* for these 2 messages, we need to
1002  * ssl->enc_read_ctx                    re-init
1003  * ssl->s3->read_sequence               zero
1004  * ssl->s3->read_mac_secret             re-init
1005  * ssl->session->read_sym_enc           assign
1006  * ssl->session->read_compression       assign
1007  * ssl->session->read_hash              assign
1008  */
1009 int dtls1_send_change_cipher_spec(SSL *s, int a, int b)
1010         {
1011         unsigned char *p;
1012
1013         if (s->state == a)
1014                 {
1015                 p=(unsigned char *)s->init_buf->data;
1016                 *p++=SSL3_MT_CCS;
1017                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1018                 s->init_num=DTLS1_CCS_HEADER_LENGTH;
1019
1020                 if (s->version == DTLS1_BAD_VER) {
1021                         s->d1->next_handshake_write_seq++;
1022                         s2n(s->d1->handshake_write_seq,p);
1023                         s->init_num+=2;
1024                 }
1025
1026                 s->init_off=0;
1027
1028                 dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
1029                         s->d1->handshake_write_seq, 0, 0);
1030
1031                 /* buffer the message to handle re-xmits */
1032                 dtls1_buffer_message(s, 1);
1033
1034                 s->state=b;
1035                 }
1036
1037         /* SSL3_ST_CW_CHANGE_B */
1038         return(dtls1_do_write(s,SSL3_RT_CHANGE_CIPHER_SPEC));
1039         }
1040
1041 static int dtls1_add_cert_to_buf(BUF_MEM *buf, unsigned long *l, X509 *x)
1042         {
1043         int n;
1044         unsigned char *p;
1045
1046         n=i2d_X509(x,NULL);
1047         if (!BUF_MEM_grow_clean(buf,(int)(n+(*l)+3)))
1048                 {
1049                 SSLerr(SSL_F_DTLS1_ADD_CERT_TO_BUF,ERR_R_BUF_LIB);
1050                 return 0;
1051                 }
1052         p=(unsigned char *)&(buf->data[*l]);
1053         l2n3(n,p);
1054         i2d_X509(x,&p);
1055         *l+=n+3;
1056
1057         return 1;
1058         }
1059 unsigned long dtls1_output_cert_chain(SSL *s, X509 *x)
1060         {
1061         unsigned char *p;
1062         int i;
1063         unsigned long l= 3 + DTLS1_HM_HEADER_LENGTH;
1064         BUF_MEM *buf;
1065
1066         /* TLSv1 sends a chain with nothing in it, instead of an alert */
1067         buf=s->init_buf;
1068         if (!BUF_MEM_grow_clean(buf,10))
1069                 {
1070                 SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_BUF_LIB);
1071                 return(0);
1072                 }
1073         if (x != NULL)
1074                 {
1075                 X509_STORE_CTX xs_ctx;
1076
1077                 if (!X509_STORE_CTX_init(&xs_ctx,s->ctx->cert_store,x,NULL))
1078                         {
1079                         SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_X509_LIB);
1080                         return(0);
1081                         }
1082
1083                 X509_verify_cert(&xs_ctx);
1084                 /* Don't leave errors in the queue */
1085                 ERR_clear_error();
1086                 for (i=0; i < sk_X509_num(xs_ctx.chain); i++)
1087                         {
1088                         x = sk_X509_value(xs_ctx.chain, i);
1089
1090                         if (!dtls1_add_cert_to_buf(buf, &l, x))
1091                                 {
1092                                 X509_STORE_CTX_cleanup(&xs_ctx);
1093                                 return 0;
1094                                 }
1095                         }
1096                 X509_STORE_CTX_cleanup(&xs_ctx);
1097                 }
1098         /* Thawte special :-) */
1099         for (i=0; i<sk_X509_num(s->ctx->extra_certs); i++)
1100                 {
1101                 x=sk_X509_value(s->ctx->extra_certs,i);
1102                 if (!dtls1_add_cert_to_buf(buf, &l, x))
1103                         return 0;
1104                 }
1105
1106         l-= (3 + DTLS1_HM_HEADER_LENGTH);
1107
1108         p=(unsigned char *)&(buf->data[DTLS1_HM_HEADER_LENGTH]);
1109         l2n3(l,p);
1110         l+=3;
1111         p=(unsigned char *)&(buf->data[0]);
1112         p = dtls1_set_message_header(s, p, SSL3_MT_CERTIFICATE, l, 0, l);
1113
1114         l+=DTLS1_HM_HEADER_LENGTH;
1115         return(l);
1116         }
1117
1118 int dtls1_read_failed(SSL *s, int code)
1119         {
1120         if ( code > 0)
1121                 {
1122                 fprintf( stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
1123                 return 1;
1124                 }
1125
1126         if (!dtls1_is_timer_expired(s))
1127                 {
1128                 /* not a timeout, none of our business,
1129                    let higher layers handle this.  in fact it's probably an error */
1130                 return code;
1131                 }
1132
1133 #ifndef OPENSSL_NO_HEARTBEATS
1134         if (!SSL_in_init(s) && !s->tlsext_hb_pending)  /* done, no need to send a retransmit */
1135 #else
1136         if (!SSL_in_init(s))  /* done, no need to send a retransmit */
1137 #endif
1138                 {
1139                 BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
1140                 return code;
1141                 }
1142
1143 #if 0 /* for now, each alert contains only one record number */
1144         item = pqueue_peek(state->rcvd_records);
1145         if ( item )
1146                 {
1147                 /* send an alert immediately for all the missing records */
1148                 }
1149         else
1150 #endif
1151
1152 #if 0  /* no more alert sending, just retransmit the last set of messages */
1153         if ( state->timeout.read_timeouts >= DTLS1_TMO_READ_COUNT)
1154                 ssl3_send_alert(s,SSL3_AL_WARNING,
1155                         DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
1156 #endif
1157
1158         return dtls1_handle_timeout(s);
1159         }
1160
1161 int
1162 dtls1_get_queue_priority(unsigned short seq, int is_ccs)
1163         {
1164         /* The index of the retransmission queue actually is the message sequence number,
1165          * since the queue only contains messages of a single handshake. However, the
1166          * ChangeCipherSpec has no message sequence number and so using only the sequence
1167          * will result in the CCS and Finished having the same index. To prevent this,
1168          * the sequence number is multiplied by 2. In case of a CCS 1 is subtracted.
1169          * This does not only differ CSS and Finished, it also maintains the order of the
1170          * index (important for priority queues) and fits in the unsigned short variable.
1171          */
1172         return seq * 2 - is_ccs;
1173         }
1174
1175 int
1176 dtls1_retransmit_buffered_messages(SSL *s)
1177         {
1178         pqueue sent = s->d1->sent_messages;
1179         piterator iter;
1180         pitem *item;
1181         hm_fragment *frag;
1182         int found = 0;
1183
1184         iter = pqueue_iterator(sent);
1185
1186         for ( item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter))
1187                 {
1188                 frag = (hm_fragment *)item->data;
1189                         if ( dtls1_retransmit_message(s,
1190                                 (unsigned short)dtls1_get_queue_priority(frag->msg_header.seq, frag->msg_header.is_ccs),
1191                                 0, &found) <= 0 && found)
1192                         {
1193                         fprintf(stderr, "dtls1_retransmit_message() failed\n");
1194                         return -1;
1195                         }
1196                 }
1197
1198         return 1;
1199         }
1200
1201 int
1202 dtls1_buffer_message(SSL *s, int is_ccs)
1203         {
1204         pitem *item;
1205         hm_fragment *frag;
1206         unsigned char seq64be[8];
1207
1208         /* this function is called immediately after a message has
1209          * been serialized */
1210         OPENSSL_assert(s->init_off == 0);
1211
1212         frag = dtls1_hm_fragment_new(s->init_num, 0);
1213         if (!frag)
1214                 return 0;
1215
1216         memcpy(frag->fragment, s->init_buf->data, s->init_num);
1217
1218         if ( is_ccs)
1219                 {
1220                 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1221                                ((s->version==DTLS1_VERSION)?DTLS1_CCS_HEADER_LENGTH:3) == (unsigned int)s->init_num);
1222                 }
1223         else
1224                 {
1225                 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
1226                         DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num);
1227                 }
1228
1229         frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
1230         frag->msg_header.seq = s->d1->w_msg_hdr.seq;
1231         frag->msg_header.type = s->d1->w_msg_hdr.type;
1232         frag->msg_header.frag_off = 0;
1233         frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
1234         frag->msg_header.is_ccs = is_ccs;
1235
1236         /* save current state*/
1237         frag->msg_header.saved_retransmit_state.enc_write_ctx = s->enc_write_ctx;
1238         frag->msg_header.saved_retransmit_state.write_hash = s->write_hash;
1239         frag->msg_header.saved_retransmit_state.compress = s->compress;
1240         frag->msg_header.saved_retransmit_state.session = s->session;
1241         frag->msg_header.saved_retransmit_state.epoch = s->d1->w_epoch;
1242
1243         memset(seq64be,0,sizeof(seq64be));
1244         seq64be[6] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1245                                                                                                                   frag->msg_header.is_ccs)>>8);
1246         seq64be[7] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
1247                                                                                                                   frag->msg_header.is_ccs));
1248
1249         item = pitem_new(seq64be, frag);
1250         if ( item == NULL)
1251                 {
1252                 dtls1_hm_fragment_free(frag);
1253                 return 0;
1254                 }
1255
1256 #if 0
1257         fprintf( stderr, "buffered messge: \ttype = %xx\n", msg_buf->type);
1258         fprintf( stderr, "\t\t\t\t\tlen = %d\n", msg_buf->len);
1259         fprintf( stderr, "\t\t\t\t\tseq_num = %d\n", msg_buf->seq_num);
1260 #endif
1261
1262         pqueue_insert(s->d1->sent_messages, item);
1263         return 1;
1264         }
1265
1266 int
1267 dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
1268         int *found)
1269         {
1270         int ret;
1271         /* XDTLS: for now assuming that read/writes are blocking */
1272         pitem *item;
1273         hm_fragment *frag ;
1274         unsigned long header_length;
1275         unsigned char seq64be[8];
1276         struct dtls1_retransmit_state saved_state;
1277         unsigned char save_write_sequence[8];
1278
1279         /*
1280           OPENSSL_assert(s->init_num == 0);
1281           OPENSSL_assert(s->init_off == 0);
1282          */
1283
1284         /* XDTLS:  the requested message ought to be found, otherwise error */
1285         memset(seq64be,0,sizeof(seq64be));
1286         seq64be[6] = (unsigned char)(seq>>8);
1287         seq64be[7] = (unsigned char)seq;
1288
1289         item = pqueue_find(s->d1->sent_messages, seq64be);
1290         if ( item == NULL)
1291                 {
1292                 fprintf(stderr, "retransmit:  message %d non-existant\n", seq);
1293                 *found = 0;
1294                 return 0;
1295                 }
1296
1297         *found = 1;
1298         frag = (hm_fragment *)item->data;
1299
1300         if ( frag->msg_header.is_ccs)
1301                 header_length = DTLS1_CCS_HEADER_LENGTH;
1302         else
1303                 header_length = DTLS1_HM_HEADER_LENGTH;
1304
1305         memcpy(s->init_buf->data, frag->fragment,
1306                 frag->msg_header.msg_len + header_length);
1307                 s->init_num = frag->msg_header.msg_len + header_length;
1308
1309         dtls1_set_message_header_int(s, frag->msg_header.type,
1310                 frag->msg_header.msg_len, frag->msg_header.seq, 0,
1311                 frag->msg_header.frag_len);
1312
1313         /* save current state */
1314         saved_state.enc_write_ctx = s->enc_write_ctx;
1315         saved_state.write_hash = s->write_hash;
1316         saved_state.compress = s->compress;
1317         saved_state.session = s->session;
1318         saved_state.epoch = s->d1->w_epoch;
1319         saved_state.epoch = s->d1->w_epoch;
1320
1321         s->d1->retransmitting = 1;
1322
1323         /* restore state in which the message was originally sent */
1324         s->enc_write_ctx = frag->msg_header.saved_retransmit_state.enc_write_ctx;
1325         s->write_hash = frag->msg_header.saved_retransmit_state.write_hash;
1326         s->compress = frag->msg_header.saved_retransmit_state.compress;
1327         s->session = frag->msg_header.saved_retransmit_state.session;
1328         s->d1->w_epoch = frag->msg_header.saved_retransmit_state.epoch;
1329
1330         if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1331         {
1332                 memcpy(save_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1333                 memcpy(s->s3->write_sequence, s->d1->last_write_sequence, sizeof(s->s3->write_sequence));
1334         }
1335
1336         ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1337                                                  SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1338
1339         /* restore current state */
1340         s->enc_write_ctx = saved_state.enc_write_ctx;
1341         s->write_hash = saved_state.write_hash;
1342         s->compress = saved_state.compress;
1343         s->session = saved_state.session;
1344         s->d1->w_epoch = saved_state.epoch;
1345
1346         if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
1347         {
1348                 memcpy(s->d1->last_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
1349                 memcpy(s->s3->write_sequence, save_write_sequence, sizeof(s->s3->write_sequence));
1350         }
1351
1352         s->d1->retransmitting = 0;
1353
1354         (void)BIO_flush(SSL_get_wbio(s));
1355         return ret;
1356         }
1357
1358 /* call this function when the buffered messages are no longer needed */
1359 void
1360 dtls1_clear_record_buffer(SSL *s)
1361         {
1362         pitem *item;
1363
1364         for(item = pqueue_pop(s->d1->sent_messages);
1365                 item != NULL; item = pqueue_pop(s->d1->sent_messages))
1366                 {
1367                 dtls1_hm_fragment_free((hm_fragment *)item->data);
1368                 pitem_free(item);
1369                 }
1370         }
1371
1372
1373 unsigned char *
1374 dtls1_set_message_header(SSL *s, unsigned char *p, unsigned char mt,
1375                         unsigned long len, unsigned long frag_off, unsigned long frag_len)
1376         {
1377         /* Don't change sequence numbers while listening */
1378         if (frag_off == 0 && !s->d1->listen)
1379                 {
1380                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1381                 s->d1->next_handshake_write_seq++;
1382                 }
1383
1384         dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1385                 frag_off, frag_len);
1386
1387         return p += DTLS1_HM_HEADER_LENGTH;
1388         }
1389
1390
1391 /* don't actually do the writing, wait till the MTU has been retrieved */
1392 static void
1393 dtls1_set_message_header_int(SSL *s, unsigned char mt,
1394                             unsigned long len, unsigned short seq_num, unsigned long frag_off,
1395                             unsigned long frag_len)
1396         {
1397         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1398
1399         msg_hdr->type = mt;
1400         msg_hdr->msg_len = len;
1401         msg_hdr->seq = seq_num;
1402         msg_hdr->frag_off = frag_off;
1403         msg_hdr->frag_len = frag_len;
1404         }
1405
1406 static void
1407 dtls1_fix_message_header(SSL *s, unsigned long frag_off,
1408                         unsigned long frag_len)
1409         {
1410         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1411
1412         msg_hdr->frag_off = frag_off;
1413         msg_hdr->frag_len = frag_len;
1414         }
1415
1416 static unsigned char *
1417 dtls1_write_message_header(SSL *s, unsigned char *p)
1418         {
1419         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1420
1421         *p++ = msg_hdr->type;
1422         l2n3(msg_hdr->msg_len, p);
1423
1424         s2n(msg_hdr->seq, p);
1425         l2n3(msg_hdr->frag_off, p);
1426         l2n3(msg_hdr->frag_len, p);
1427
1428         return p;
1429         }
1430
1431 unsigned int
1432 dtls1_min_mtu(void)
1433         {
1434         return (g_probable_mtu[(sizeof(g_probable_mtu) /
1435                 sizeof(g_probable_mtu[0])) - 1]);
1436         }
1437
1438 static unsigned int
1439 dtls1_guess_mtu(unsigned int curr_mtu)
1440         {
1441         unsigned int i;
1442
1443         if ( curr_mtu == 0 )
1444                 return g_probable_mtu[0] ;
1445
1446         for ( i = 0; i < sizeof(g_probable_mtu)/sizeof(g_probable_mtu[0]); i++)
1447                 if ( curr_mtu > g_probable_mtu[i])
1448                         return g_probable_mtu[i];
1449
1450         return curr_mtu;
1451         }
1452
1453 void
1454 dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
1455         {
1456         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
1457         msg_hdr->type = *(data++);
1458         n2l3(data, msg_hdr->msg_len);
1459
1460         n2s(data, msg_hdr->seq);
1461         n2l3(data, msg_hdr->frag_off);
1462         n2l3(data, msg_hdr->frag_len);
1463         }
1464
1465 void
1466 dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st *ccs_hdr)
1467         {
1468         memset(ccs_hdr, 0x00, sizeof(struct ccs_header_st));
1469
1470         ccs_hdr->type = *(data++);
1471         }
1472
1473 int dtls1_shutdown(SSL *s)
1474         {
1475         int ret;
1476 #ifndef OPENSSL_NO_SCTP
1477         if (BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
1478             !(s->shutdown & SSL_SENT_SHUTDOWN))
1479                 {
1480                 ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
1481                 if (ret < 0) return -1;
1482
1483                 if (ret == 0)
1484                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1, NULL);
1485                 }
1486 #endif
1487         ret = ssl3_shutdown(s);
1488 #ifndef OPENSSL_NO_SCTP
1489         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
1490 #endif
1491         return ret;
1492         }
1493
1494 #ifndef OPENSSL_NO_HEARTBEATS
1495 int
1496 dtls1_process_heartbeat(SSL *s)
1497         {
1498         unsigned char *p = &s->s3->rrec.data[0], *pl;
1499         unsigned short hbtype;
1500         unsigned int payload;
1501         unsigned int padding = 16; /* Use minimum padding */
1502
1503         if (s->msg_callback)
1504                 s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
1505                         &s->s3->rrec.data[0], s->s3->rrec.length,
1506                         s, s->msg_callback_arg);
1507
1508         /* Read type and payload length first */
1509         if (1 + 2 + 16 > s->s3->rrec.length)
1510                 return 0; /* silently discard */
1511         if (s->s3->rrec.length > SSL3_RT_MAX_PLAIN_LENGTH)
1512                 return 0; /* silently discard per RFC 6520 sec. 4 */
1513
1514         hbtype = *p++;
1515         n2s(p, payload);
1516         if (1 + 2 + payload + 16 > s->s3->rrec.length)
1517                 return 0; /* silently discard per RFC 6520 sec. 4 */
1518         pl = p;
1519
1520         if (hbtype == TLS1_HB_REQUEST)
1521                 {
1522                 unsigned char *buffer, *bp;
1523                 unsigned int write_length = 1 /* heartbeat type */ +
1524                                             2 /* heartbeat length */ +
1525                                             payload + padding;
1526                 int r;
1527
1528                 if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
1529                         return 0;
1530
1531                 /* Allocate memory for the response, size is 1 byte
1532                  * message type, plus 2 bytes payload length, plus
1533                  * payload, plus padding
1534                  */
1535                 buffer = OPENSSL_malloc(write_length);
1536                 bp = buffer;
1537
1538                 /* Enter response type, length and copy payload */
1539                 *bp++ = TLS1_HB_RESPONSE;
1540                 s2n(payload, bp);
1541                 memcpy(bp, pl, payload);
1542                 bp += payload;
1543                 /* Random padding */
1544                 RAND_pseudo_bytes(bp, padding);
1545
1546                 r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, write_length);
1547
1548                 if (r >= 0 && s->msg_callback)
1549                         s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1550                                 buffer, write_length,
1551                                 s, s->msg_callback_arg);
1552
1553                 OPENSSL_free(buffer);
1554
1555                 if (r < 0)
1556                         return r;
1557                 }
1558         else if (hbtype == TLS1_HB_RESPONSE)
1559                 {
1560                 unsigned int seq;
1561
1562                 /* We only send sequence numbers (2 bytes unsigned int),
1563                  * and 16 random bytes, so we just try to read the
1564                  * sequence number */
1565                 n2s(pl, seq);
1566
1567                 if (payload == 18 && seq == s->tlsext_hb_seq)
1568                         {
1569                         dtls1_stop_timer(s);
1570                         s->tlsext_hb_seq++;
1571                         s->tlsext_hb_pending = 0;
1572                         }
1573                 }
1574
1575         return 0;
1576         }
1577
1578 int
1579 dtls1_heartbeat(SSL *s)
1580         {
1581         unsigned char *buf, *p;
1582         int ret;
1583         unsigned int payload = 18; /* Sequence number + random bytes */
1584         unsigned int padding = 16; /* Use minimum padding */
1585
1586         /* Only send if peer supports and accepts HB requests... */
1587         if (!(s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED) ||
1588             s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS)
1589                 {
1590                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
1591                 return -1;
1592                 }
1593
1594         /* ...and there is none in flight yet... */
1595         if (s->tlsext_hb_pending)
1596                 {
1597                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_TLS_HEARTBEAT_PENDING);
1598                 return -1;
1599                 }
1600
1601         /* ...and no handshake in progress. */
1602         if (SSL_in_init(s) || s->in_handshake)
1603                 {
1604                 SSLerr(SSL_F_DTLS1_HEARTBEAT,SSL_R_UNEXPECTED_MESSAGE);
1605                 return -1;
1606                 }
1607
1608         /* Check if padding is too long, payload and padding
1609          * must not exceed 2^14 - 3 = 16381 bytes in total.
1610          */
1611         OPENSSL_assert(payload + padding <= 16381);
1612
1613         /* Create HeartBeat message, we just use a sequence number
1614          * as payload to distuingish different messages and add
1615          * some random stuff.
1616          *  - Message Type, 1 byte
1617          *  - Payload Length, 2 bytes (unsigned int)
1618          *  - Payload, the sequence number (2 bytes uint)
1619          *  - Payload, random bytes (16 bytes uint)
1620          *  - Padding
1621          */
1622         buf = OPENSSL_malloc(1 + 2 + payload + padding);
1623         p = buf;
1624         /* Message Type */
1625         *p++ = TLS1_HB_REQUEST;
1626         /* Payload length (18 bytes here) */
1627         s2n(payload, p);
1628         /* Sequence number */
1629         s2n(s->tlsext_hb_seq, p);
1630         /* 16 random bytes */
1631         RAND_pseudo_bytes(p, 16);
1632         p += 16;
1633         /* Random padding */
1634         RAND_pseudo_bytes(p, padding);
1635
1636         ret = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buf, 3 + payload + padding);
1637         if (ret >= 0)
1638                 {
1639                 if (s->msg_callback)
1640                         s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
1641                                 buf, 3 + payload + padding,
1642                                 s, s->msg_callback_arg);
1643
1644                 dtls1_start_timer(s);
1645                 s->tlsext_hb_pending = 1;
1646                 }
1647
1648         OPENSSL_free(buf);
1649
1650         return ret;
1651         }
1652 #endif