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
 127 /* XDTLS:  figure out the right values */
 128 static unsigned int g_probable_mtu[] = {1500 - 28, 512 - 28, 256 - 28};
 129
 130 static unsigned int dtls1_min_mtu(void);
 131 static unsigned int dtls1_guess_mtu(unsigned int curr_mtu);
 132 static void dtls1_fix_message_header(SSL *s, unsigned long frag_off,
 133         unsigned long frag_len);
 134 static unsigned char *dtls1_write_message_header(SSL *s,
 135         unsigned char *p);
 136 static void dtls1_set_message_header_int(SSL *s, unsigned char mt,
 137         unsigned long len, unsigned short seq_num, unsigned long frag_off,
 138         unsigned long frag_len);
 139 static int dtls1_retransmit_buffered_messages(SSL *s);
 140 static long dtls1_get_message_fragment(SSL *s, int st1, int stn,
 141         long max, int *ok);
 142
 143 static hm_fragment *
 144 dtls1_hm_fragment_new(unsigned long frag_len)
 145         {
 146         hm_fragment *frag = NULL;
 147         unsigned char *buf = NULL;
 148
 149         frag = (hm_fragment *)OPENSSL_malloc(sizeof(hm_fragment));
 150         if ( frag == NULL)
 151                 return NULL;
 152
 153         if (frag_len)
 154                 {
 155                 buf = (unsigned char *)OPENSSL_malloc(frag_len);
 156                 if ( buf == NULL)
 157                         {
 158                         OPENSSL_free(frag);
 159                         return NULL;
 160                         }
 161                 }
 162
 163         /* zero length fragment gets zero frag->fragment */
 164         frag->fragment = buf;
 165
 166         return frag;
 167         }
 168
 169 static void
 170 dtls1_hm_fragment_free(hm_fragment *frag)
 171         {
 172         if (frag->fragment) OPENSSL_free(frag->fragment);
 173         OPENSSL_free(frag);
 174         }
 175
 176 /* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */
 177 int dtls1_do_write(SSL *s, int type)
 178         {
 179         int ret;
 180         int curr_mtu;
 181         unsigned int len, frag_off;
 182
 183         /* AHA!  Figure out the MTU, and stick to the right size */
 184         if ( ! (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))
 185                 {
 186                 s->d1->mtu =
 187                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
 188
 189                 /* I've seen the kernel return bogus numbers when it doesn't know
 190                  * (initial write), so just make sure we have a reasonable number */
 191                 if ( s->d1->mtu < dtls1_min_mtu())
 192                         {
 193                         s->d1->mtu = 0;
 194                         s->d1->mtu = dtls1_guess_mtu(s->d1->mtu);
 195                         BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
 196                                 s->d1->mtu, NULL);
 197                         }
 198                 }
 199 #if 0
 200         mtu = s->d1->mtu;
 201
 202         fprintf(stderr, "using MTU = %d\n", mtu);
 203
 204         mtu -= (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
 205
 206         curr_mtu = mtu - BIO_wpending(SSL_get_wbio(s));
 207
 208         if ( curr_mtu > 0)
 209                 mtu = curr_mtu;
 210         else if ( ( ret = BIO_flush(SSL_get_wbio(s))) <= 0)
 211                 return ret;
 212
 213         if ( BIO_wpending(SSL_get_wbio(s)) + s->init_num >= mtu)
 214                 {
 215                 ret = BIO_flush(SSL_get_wbio(s));
 216                 if ( ret <= 0)
 217                         return ret;
 218                 mtu = s->d1->mtu - (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
 219                 }
 220
 221         OPENSSL_assert(mtu > 0);  /* should have something reasonable now */
 222
 223 #endif
 224
 225         if ( s->init_off == 0  && type == SSL3_RT_HANDSHAKE)
 226                 OPENSSL_assert(s->init_num ==
 227                         (int)s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH);
 228
 229         frag_off = 0;
 230         while( s->init_num)
 231                 {
 232                 curr_mtu = s->d1->mtu - BIO_wpending(SSL_get_wbio(s)) -
 233                         DTLS1_RT_HEADER_LENGTH;
 234
 235                 if ( curr_mtu <= DTLS1_HM_HEADER_LENGTH)
 236                         {
 237                         /* grr.. we could get an error if MTU picked was wrong */
 238                         ret = BIO_flush(SSL_get_wbio(s));
 239                         if ( ret <= 0)
 240                                 return ret;
 241                         curr_mtu = s->d1->mtu - DTLS1_RT_HEADER_LENGTH;
 242                         }
 243
 244                 if ( s->init_num > curr_mtu)
 245                         len = curr_mtu;
 246                 else
 247                         len = s->init_num;
 248
 249
 250                 /* XDTLS: this function is too long.  split out the CCS part */
 251                 if ( type == SSL3_RT_HANDSHAKE)
 252                         {
 253                         if ( s->init_off != 0)
 254                                 {
 255                                 OPENSSL_assert(s->init_off > DTLS1_HM_HEADER_LENGTH);
 256                                 s->init_off -= DTLS1_HM_HEADER_LENGTH;
 257                                 s->init_num += DTLS1_HM_HEADER_LENGTH;
 258
 259                                 /* write atleast DTLS1_HM_HEADER_LENGTH bytes */
 260                                 if ( len <= DTLS1_HM_HEADER_LENGTH)
 261                                         len += DTLS1_HM_HEADER_LENGTH;
 262                                 }
 263
 264                         dtls1_fix_message_header(s, frag_off,
 265                                 len - DTLS1_HM_HEADER_LENGTH);
 266
 267                         dtls1_write_message_header(s, (unsigned char *)&s->init_buf->data[s->init_off]);
 268
 269                         OPENSSL_assert(len >= DTLS1_HM_HEADER_LENGTH);
 270                         }
 271
 272                 ret=dtls1_write_bytes(s,type,&s->init_buf->data[s->init_off],
 273                         len);
 274                 if (ret < 0)
 275                         {
 276                         /* might need to update MTU here, but we don't know
 277                          * which previous packet caused the failure -- so can't
 278                          * really retransmit anything.  continue as if everything
 279                          * is fine and wait for an alert to handle the
 280                          * retransmit
 281                          */
 282                         if ( BIO_ctrl(SSL_get_wbio(s),
 283                                 BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL))
 284                                 s->d1->mtu = BIO_ctrl(SSL_get_wbio(s),
 285                                         BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
 286                         else
 287                                 return(-1);
 288                         }
 289                 else
 290                         {
 291
 292                         /* bad if this assert fails, only part of the handshake
 293                          * message got sent.  but why would this happen? */
 294                         OPENSSL_assert(len == (unsigned int)ret);
 295
 296                         if (type == SSL3_RT_HANDSHAKE && ! s->d1->retransmitting)
 297                                 {
 298                                 /* should not be done for 'Hello Request's, but in that case
 299                                  * we'll ignore the result anyway */
 300                                 unsigned char *p = (unsigned char *)&s->init_buf->data[s->init_off];
 301                                 const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
 302                                 int xlen;
 303
 304                                 if (frag_off == 0)
 305                                         {
 306                                         /* reconstruct message header is if it
 307                                          * is being sent in single fragment */
 308                                         *p++ = msg_hdr->type;
 309                                         l2n3(msg_hdr->msg_len,p);
 310                                         s2n (msg_hdr->seq,p);
 311                                         l2n3(0,p);
 312                                         l2n3(msg_hdr->msg_len,p);
 313                                         p  -= DTLS1_HM_HEADER_LENGTH;
 314                                         xlen = ret;
 315                                         }
 316                                 else
 317                                         {
 318                                         p  += DTLS1_HM_HEADER_LENGTH;
 319                                         xlen = ret - DTLS1_HM_HEADER_LENGTH;
 320                                         }
 321
 322                                 ssl3_finish_mac(s, p, xlen);
 323                                 }
 324
 325                         if (ret == s->init_num)
 326                                 {
 327                                 if (s->msg_callback)
 328                                         s->msg_callback(1, s->version, type, s->init_buf->data,
 329                                                 (size_t)(s->init_off + s->init_num), s,
 330                                                 s->msg_callback_arg);
 331
 332                                 s->init_off = 0;  /* done writing this message */
 333                                 s->init_num = 0;
 334
 335                                 return(1);
 336                                 }
 337                         s->init_off+=ret;
 338                         s->init_num-=ret;
 339                         frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
 340                         }
 341                 }
 342         return(0);
 343         }
 344
 345
 346 /* Obtain handshake message of message type 'mt' (any if mt == -1),
 347  * maximum acceptable body length 'max'.
 348  * Read an entire handshake message.  Handshake messages arrive in
 349  * fragments.
 350  */
 351 long dtls1_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
 352         {
 353         int i, al;
 354         struct hm_header_st *msg_hdr;
 355
 356         /* s3->tmp is used to store messages that are unexpected, caused
 357          * by the absence of an optional handshake message */
 358         if (s->s3->tmp.reuse_message)
 359                 {
 360                 s->s3->tmp.reuse_message=0;
 361                 if ((mt >= 0) && (s->s3->tmp.message_type != mt))
 362                         {
 363                         al=SSL_AD_UNEXPECTED_MESSAGE;
 364                         SSLerr(SSL_F_DTLS1_GET_MESSAGE,SSL_R_UNEXPECTED_MESSAGE);
 365                         goto f_err;
 366                         }
 367                 *ok=1;
 368                 s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 369                 s->init_num = (int)s->s3->tmp.message_size;
 370                 return s->init_num;
 371                 }
 372
 373         msg_hdr = &s->d1->r_msg_hdr;
 374         do
 375                 {
 376                 if ( msg_hdr->frag_off == 0)
 377                         {
 378                         /* s->d1->r_message_header.msg_len = 0; */
 379                         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
 380                         }
 381
 382                 i = dtls1_get_message_fragment(s, st1, stn, max, ok);
 383                 if ( i == DTLS1_HM_BAD_FRAGMENT ||
 384                         i == DTLS1_HM_FRAGMENT_RETRY)  /* bad fragment received */
 385                         continue;
 386                 else if ( i <= 0 && !*ok)
 387                         return i;
 388
 389                 /* Note that s->init_sum is used as a counter summing
 390                  * up fragments' lengths: as soon as they sum up to
 391                  * handshake packet length, we assume we have got all
 392                  * the fragments. Overlapping fragments would cause
 393                  * premature termination, so we don't expect overlaps.
 394                  * Well, handling overlaps would require something more
 395                  * drastic. Indeed, as it is now there is no way to
 396                  * tell if out-of-order fragment from the middle was
 397                  * the last. '>=' is the best/least we can do to control
 398                  * the potential damage caused by malformed overlaps. */
 399                 if ((unsigned int)s->init_num >= msg_hdr->msg_len)
 400                         {
 401                         unsigned char *p = (unsigned char *)s->init_buf->data;
 402                         unsigned long msg_len = msg_hdr->msg_len;
 403
 404                         /* reconstruct message header as if it was
 405                          * sent in single fragment */
 406                         *(p++) = msg_hdr->type;
 407                         l2n3(msg_len,p);
 408                         s2n (msg_hdr->seq,p);
 409                         l2n3(0,p);
 410                         l2n3(msg_len,p);
 411                         p       -= DTLS1_HM_HEADER_LENGTH;
 412                         msg_len += DTLS1_HM_HEADER_LENGTH;
 413
 414                         ssl3_finish_mac(s, p, msg_len);
 415                         if (s->msg_callback)
 416                                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 417                                         p, msg_len,
 418                                         s, s->msg_callback_arg);
 419
 420                         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
 421
 422                         s->d1->handshake_read_seq++;
 423                         /* we just read a handshake message from the other side:
 424                          * this means that we don't need to retransmit of the
 425                          * buffered messages.
 426                          * XDTLS: may be able clear out this
 427                          * buffer a little sooner (i.e if an out-of-order
 428                          * handshake message/record is received at the record
 429                          * layer.
 430                          * XDTLS: exception is that the server needs to
 431                          * know that change cipher spec and finished messages
 432                          * have been received by the client before clearing this
 433                          * buffer.  this can simply be done by waiting for the
 434                          * first data  segment, but is there a better way?  */
 435                         dtls1_clear_record_buffer(s);
 436
 437                         s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
 438                         return s->init_num;
 439                         }
 440                 else
 441                         msg_hdr->frag_off = i;
 442                 } while(1) ;
 443
 444 f_err:
 445         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 446         *ok = 0;
 447         return -1;
 448         }
 449
 450
 451 static int dtls1_preprocess_fragment(SSL *s,struct hm_header_st *msg_hdr,int max)
 452         {
 453         size_t frag_off,frag_len,msg_len;
 454
 455         msg_len  = msg_hdr->msg_len;
 456         frag_off = msg_hdr->frag_off;
 457         frag_len = msg_hdr->frag_len;
 458
 459         /* sanity checking */
 460         if ( (frag_off+frag_len) > msg_len)
 461                 {
 462                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 463                 return SSL_AD_ILLEGAL_PARAMETER;
 464                 }
 465
 466         if ( (frag_off+frag_len) > (unsigned long)max)
 467                 {
 468                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 469                 return SSL_AD_ILLEGAL_PARAMETER;
 470                 }
 471
 472         if ( s->d1->r_msg_hdr.frag_off == 0) /* first fragment */
 473                 {
 474                 /* msg_len is limited to 2^24, but is effectively checked
 475                  * against max above */
 476                 if (!BUF_MEM_grow_clean(s->init_buf,msg_len+DTLS1_HM_HEADER_LENGTH))
 477                         {
 478                         SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,ERR_R_BUF_LIB);
 479                         return SSL_AD_INTERNAL_ERROR;
 480                         }
 481
 482                 s->s3->tmp.message_size  = msg_len;
 483                 s->d1->r_msg_hdr.msg_len = msg_len;
 484                 s->s3->tmp.message_type  = msg_hdr->type;
 485                 s->d1->r_msg_hdr.type    = msg_hdr->type;
 486                 s->d1->r_msg_hdr.seq     = msg_hdr->seq;
 487                 }
 488         else if (msg_len != s->d1->r_msg_hdr.msg_len)
 489                 {
 490                 /* They must be playing with us! BTW, failure to enforce
 491                  * upper limit would open possibility for buffer overrun. */
 492                 SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
 493                 return SSL_AD_ILLEGAL_PARAMETER;
 494                 }
 495
 496         return 0; /* no error */
 497         }
 498
 499
 500 static int
 501 dtls1_retrieve_buffered_fragment(SSL *s, long max, int *ok)
 502         {
 503         /* (0) check whether the desired fragment is available
 504          * if so:
 505          * (1) copy over the fragment to s->init_buf->data[]
 506          * (2) update s->init_num
 507          */
 508         pitem *item;
 509         hm_fragment *frag;
 510         int al;
 511
 512         *ok = 0;
 513         item = pqueue_peek(s->d1->buffered_messages);
 514         if ( item == NULL)
 515                 return 0;
 516
 517         frag = (hm_fragment *)item->data;
 518
 519         if ( s->d1->handshake_read_seq == frag->msg_header.seq)
 520                 {
 521                 pqueue_pop(s->d1->buffered_messages);
 522
 523                 al=dtls1_preprocess_fragment(s,&frag->msg_header,max);
 524
 525                 if (al==0) /* no alert */
 526                         {
 527                         unsigned char *p = (unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
 528                         memcpy(&p[frag->msg_header.frag_off],
 529                                 frag->fragment,frag->msg_header.frag_len);
 530                         }
 531
 532                 dtls1_hm_fragment_free(frag);
 533                 pitem_free(item);
 534
 535                 if (al==0)
 536                         {
 537                         *ok = 1;
 538                         return frag->msg_header.frag_len;
 539                         }
 540
 541                 ssl3_send_alert(s,SSL3_AL_FATAL,al);
 542                 s->init_num = 0;
 543                 *ok = 0;
 544                 return -1;
 545                 }
 546         else
 547                 return 0;
 548         }
 549
 550
 551 static int
 552 dtls1_process_out_of_seq_message(SSL *s, struct hm_header_st* msg_hdr, int *ok)
 553 {
 554         int i=-1;
 555         hm_fragment *frag = NULL;
 556         pitem *item = NULL;
 557         unsigned char seq64be[8];
 558         unsigned long frag_len = msg_hdr->frag_len;
 559
 560         if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len)
 561                 goto err;
 562
 563         if (msg_hdr->seq <= s->d1->handshake_read_seq)
 564                 {
 565                 unsigned char devnull [256];
 566
 567                 while (frag_len)
 568                         {
 569                         i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 570                                 devnull,
 571                                 frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
 572                         if (i<=0) goto err;
 573                         frag_len -= i;
 574                         }
 575                 }
 576
 577         frag = dtls1_hm_fragment_new(frag_len);
 578         if ( frag == NULL)
 579                 goto err;
 580
 581         memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
 582
 583         if (frag_len)
 584                 {
 585                 /* read the body of the fragment (header has already been read */
 586                 i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 587                         frag->fragment,frag_len,0);
 588                 if (i<=0 || (unsigned long)i!=frag_len)
 589                         goto err;
 590                 }
 591
 592         memset(seq64be,0,sizeof(seq64be));
 593         seq64be[6] = (unsigned char)(msg_hdr->seq>>8);
 594         seq64be[7] = (unsigned char)(msg_hdr->seq);
 595
 596         item = pitem_new(seq64be, frag);
 597         if ( item == NULL)
 598                 goto err;
 599
 600         pqueue_insert(s->d1->buffered_messages, item);
 601         return DTLS1_HM_FRAGMENT_RETRY;
 602
 603 err:
 604         if ( frag != NULL) dtls1_hm_fragment_free(frag);
 605         if ( item != NULL) OPENSSL_free(item);
 606         *ok = 0;
 607         return i;
 608         }
 609
 610
 611 static long
 612 dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
 613         {
 614         unsigned char wire[DTLS1_HM_HEADER_LENGTH];
 615         unsigned long l, frag_off, frag_len;
 616         int i,al;
 617         struct hm_header_st msg_hdr;
 618
 619         /* see if we have the required fragment already */
 620         if ((frag_len = dtls1_retrieve_buffered_fragment(s,max,ok)) || *ok)
 621                 {
 622                 if (*ok)        s->init_num += frag_len;
 623                 return frag_len;
 624                 }
 625
 626         /* read handshake message header */
 627         i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,wire,
 628                 DTLS1_HM_HEADER_LENGTH, 0);
 629         if (i <= 0)     /* nbio, or an error */
 630                 {
 631                 s->rwstate=SSL_READING;
 632                 *ok = 0;
 633                 return i;
 634                 }
 635         OPENSSL_assert(i == DTLS1_HM_HEADER_LENGTH);
 636
 637         /* parse the message fragment header */
 638         dtls1_get_message_header(wire, &msg_hdr);
 639
 640         /*
 641          * if this is a future (or stale) message it gets buffered
 642          * (or dropped)--no further processing at this time
 643          */
 644         if ( msg_hdr.seq != s->d1->handshake_read_seq)
 645                 return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
 646
 647         l = msg_hdr.msg_len;
 648         frag_off = msg_hdr.frag_off;
 649         frag_len = msg_hdr.frag_len;
 650
 651         if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
 652                 wire[0] == SSL3_MT_HELLO_REQUEST)
 653                 {
 654                 /* The server may always send 'Hello Request' messages --
 655                  * we are doing a handshake anyway now, so ignore them
 656                  * if their format is correct. Does not count for
 657                  * 'Finished' MAC. */
 658                 if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0)
 659                         {
 660                         if (s->msg_callback)
 661                                 s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 662                                         wire, DTLS1_HM_HEADER_LENGTH, s,
 663                                         s->msg_callback_arg);
 664
 665                         s->init_num = 0;
 666                         return dtls1_get_message_fragment(s, st1, stn,
 667                                 max, ok);
 668                         }
 669                 else /* Incorrectly formated Hello request */
 670                         {
 671                         al=SSL_AD_UNEXPECTED_MESSAGE;
 672                         SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
 673                         goto f_err;
 674                         }
 675                 }
 676
 677         if ((al=dtls1_preprocess_fragment(s,&msg_hdr,max)))
 678                 goto f_err;
 679
 680         /* XDTLS:  ressurect this when restart is in place */
 681         s->state=stn;
 682
 683         if ( frag_len > 0)
 684                 {
 685                 unsigned char *p=(unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
 686
 687                 i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
 688                         &p[frag_off],frag_len,0);
 689                 /* XDTLS:  fix this--message fragments cannot span multiple packets */
 690                 if (i <= 0)
 691                         {
 692                         s->rwstate=SSL_READING;
 693                         *ok = 0;
 694                         return i;
 695                         }
 696                 }
 697         else
 698                 i = 0;
 699
 700         /* XDTLS:  an incorrectly formatted fragment should cause the
 701          * handshake to fail */
 702         OPENSSL_assert(i == (int)frag_len);
 703
 704         *ok = 1;
 705
 706         /* Note that s->init_num is *not* used as current offset in
 707          * s->init_buf->data, but as a counter summing up fragments'
 708          * lengths: as soon as they sum up to handshake packet
 709          * length, we assume we have got all the fragments. */
 710         s->init_num += frag_len;
 711         return frag_len;
 712
 713 f_err:
 714         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 715         s->init_num = 0;
 716
 717         *ok=0;
 718         return(-1);
 719         }
 720
 721 int dtls1_send_finished(SSL *s, int a, int b, const char *sender, int slen)
 722         {
 723         unsigned char *p,*d;
 724         int i;
 725         unsigned long l;
 726
 727         if (s->state == a)
 728                 {
 729                 d=(unsigned char *)s->init_buf->data;
 730                 p= &(d[DTLS1_HM_HEADER_LENGTH]);
 731
 732                 i=s->method->ssl3_enc->final_finish_mac(s,
 733                         sender,slen,s->s3->tmp.finish_md);
 734                 s->s3->tmp.finish_md_len = i;
 735                 memcpy(p, s->s3->tmp.finish_md, i);
 736                 p+=i;
 737                 l=i;
 738
 739 #ifdef OPENSSL_SYS_WIN16
 740                 /* MSVC 1.5 does not clear the top bytes of the word unless
 741                  * I do this.
 742                  */
 743                 l&=0xffff;
 744 #endif
 745
 746                 d = dtls1_set_message_header(s, d, SSL3_MT_FINISHED, l, 0, l);
 747                 s->init_num=(int)l+DTLS1_HM_HEADER_LENGTH;
 748                 s->init_off=0;
 749
 750                 /* buffer the message to handle re-xmits */
 751                 dtls1_buffer_message(s, 0);
 752
 753                 s->state=b;
 754                 }
 755
 756         /* SSL3_ST_SEND_xxxxxx_HELLO_B */
 757         return(dtls1_do_write(s,SSL3_RT_HANDSHAKE));
 758         }
 759
 760 /* for these 2 messages, we need to
 761  * ssl->enc_read_ctx                    re-init
 762  * ssl->s3->read_sequence               zero
 763  * ssl->s3->read_mac_secret             re-init
 764  * ssl->session->read_sym_enc           assign
 765  * ssl->session->read_compression       assign
 766  * ssl->session->read_hash              assign
 767  */
 768 int dtls1_send_change_cipher_spec(SSL *s, int a, int b)
 769         {
 770         unsigned char *p;
 771
 772         if (s->state == a)
 773                 {
 774                 p=(unsigned char *)s->init_buf->data;
 775                 *p++=SSL3_MT_CCS;
 776                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
 777                 s->init_num=DTLS1_CCS_HEADER_LENGTH;
 778                 s->init_off=0;
 779
 780                 dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
 781                         s->d1->handshake_write_seq, 0, 0);
 782
 783                 /* buffer the message to handle re-xmits */
 784                 dtls1_buffer_message(s, 1);
 785
 786                 s->state=b;
 787                 }
 788
 789         /* SSL3_ST_CW_CHANGE_B */
 790         return(dtls1_do_write(s,SSL3_RT_CHANGE_CIPHER_SPEC));
 791         }
 792
 793 unsigned long dtls1_output_cert_chain(SSL *s, X509 *x)
 794         {
 795         unsigned char *p;
 796         int n,i;
 797         unsigned long l= 3 + DTLS1_HM_HEADER_LENGTH;
 798         BUF_MEM *buf;
 799         X509_STORE_CTX xs_ctx;
 800         X509_OBJECT obj;
 801
 802         /* TLSv1 sends a chain with nothing in it, instead of an alert */
 803         buf=s->init_buf;
 804         if (!BUF_MEM_grow_clean(buf,10))
 805                 {
 806                 SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_BUF_LIB);
 807                 return(0);
 808                 }
 809         if (x != NULL)
 810                 {
 811                 if(!X509_STORE_CTX_init(&xs_ctx,s->ctx->cert_store,NULL,NULL))
 812                         {
 813                         SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_X509_LIB);
 814                         return(0);
 815                         }
 816
 817                 for (;;)
 818                         {
 819                         n=i2d_X509(x,NULL);
 820                         if (!BUF_MEM_grow_clean(buf,(n+l+3)))
 821                                 {
 822                                 SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_BUF_LIB);
 823                                 return(0);
 824                                 }
 825                         p=(unsigned char *)&(buf->data[l]);
 826                         l2n3(n,p);
 827                         i2d_X509(x,&p);
 828                         l+=n+3;
 829                         if (X509_NAME_cmp(X509_get_subject_name(x),
 830                                 X509_get_issuer_name(x)) == 0) break;
 831
 832                         i=X509_STORE_get_by_subject(&xs_ctx,X509_LU_X509,
 833                                 X509_get_issuer_name(x),&obj);
 834                         if (i <= 0) break;
 835                         x=obj.data.x509;
 836                         /* Count is one too high since the X509_STORE_get uped the
 837                          * ref count */
 838                         X509_free(x);
 839                         }
 840
 841                 X509_STORE_CTX_cleanup(&xs_ctx);
 842                 }
 843
 844         /* Thawte special :-) */
 845         if (s->ctx->extra_certs != NULL)
 846         for (i=0; i<sk_X509_num(s->ctx->extra_certs); i++)
 847                 {
 848                 x=sk_X509_value(s->ctx->extra_certs,i);
 849                 n=i2d_X509(x,NULL);
 850                 if (!BUF_MEM_grow_clean(buf,(n+l+3)))
 851                         {
 852                         SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_BUF_LIB);
 853                         return(0);
 854                         }
 855                 p=(unsigned char *)&(buf->data[l]);
 856                 l2n3(n,p);
 857                 i2d_X509(x,&p);
 858                 l+=n+3;
 859                 }
 860
 861         l-= (3 + DTLS1_HM_HEADER_LENGTH);
 862
 863         p=(unsigned char *)&(buf->data[DTLS1_HM_HEADER_LENGTH]);
 864         l2n3(l,p);
 865         l+=3;
 866         p=(unsigned char *)&(buf->data[0]);
 867         p = dtls1_set_message_header(s, p, SSL3_MT_CERTIFICATE, l, 0, l);
 868
 869         l+=DTLS1_HM_HEADER_LENGTH;
 870         return(l);
 871         }
 872
 873 int dtls1_read_failed(SSL *s, int code)
 874         {
 875         DTLS1_STATE *state;
 876         BIO *bio;
 877         int send_alert = 0;
 878
 879         if ( code > 0)
 880                 {
 881                 fprintf( stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
 882                 return 1;
 883                 }
 884
 885         bio = SSL_get_rbio(s);
 886         if ( ! BIO_dgram_recv_timedout(bio))
 887                 {
 888                 /* not a timeout, none of our business,
 889                    let higher layers handle this.  in fact it's probably an error */
 890                 return code;
 891                 }
 892
 893         if ( ! SSL_in_init(s))  /* done, no need to send a retransmit */
 894                 {
 895                 BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
 896                 return code;
 897                 }
 898
 899         state = s->d1;
 900         state->timeout.num_alerts++;
 901         if ( state->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT)
 902                 {
 903                 /* fail the connection, enough alerts have been sent */
 904                 SSLerr(SSL_F_DTLS1_READ_FAILED,SSL_R_READ_TIMEOUT_EXPIRED);
 905                 return 0;
 906                 }
 907
 908         state->timeout.read_timeouts++;
 909         if ( state->timeout.read_timeouts > DTLS1_TMO_READ_COUNT)
 910                 {
 911                 send_alert = 1;
 912                 state->timeout.read_timeouts = 1;
 913                 }
 914
 915
 916 #if 0 /* for now, each alert contains only one record number */
 917         item = pqueue_peek(state->rcvd_records);
 918         if ( item )
 919                 {
 920                 /* send an alert immediately for all the missing records */
 921                 }
 922         else
 923 #endif
 924
 925 #if 0  /* no more alert sending, just retransmit the last set of messages */
 926                 if ( send_alert)
 927                         ssl3_send_alert(s,SSL3_AL_WARNING,
 928                                 DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
 929 #endif
 930
 931         return dtls1_retransmit_buffered_messages(s) ;
 932         }
 933
 934
 935 static int
 936 dtls1_retransmit_buffered_messages(SSL *s)
 937         {
 938         pqueue sent = s->d1->sent_messages;
 939         piterator iter;
 940         pitem *item;
 941         hm_fragment *frag;
 942         int found = 0;
 943
 944         iter = pqueue_iterator(sent);
 945
 946         for ( item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter))
 947                 {
 948                 frag = (hm_fragment *)item->data;
 949                 if ( dtls1_retransmit_message(s, frag->msg_header.seq, 0, &found) <= 0 &&
 950                         found)
 951                         {
 952                         fprintf(stderr, "dtls1_retransmit_message() failed\n");
 953                         return -1;
 954                         }
 955                 }
 956
 957         return 1;
 958         }
 959
 960 int
 961 dtls1_buffer_message(SSL *s, int is_ccs)
 962         {
 963         pitem *item;
 964         hm_fragment *frag;
 965         unsigned char seq64be[8];
 966         unsigned int epoch = s->d1->w_epoch;
 967
 968         /* this function is called immediately after a message has
 969          * been serialized */
 970         OPENSSL_assert(s->init_off == 0);
 971
 972         frag = dtls1_hm_fragment_new(s->init_num);
 973
 974         memcpy(frag->fragment, s->init_buf->data, s->init_num);
 975
 976         if ( is_ccs)
 977                 {
 978                 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
 979                         DTLS1_CCS_HEADER_LENGTH == (unsigned int)s->init_num);
 980                 epoch++;
 981                 }
 982         else
 983                 {
 984                 OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
 985                         DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num);
 986                 }
 987
 988         frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
 989         frag->msg_header.seq = s->d1->w_msg_hdr.seq;
 990         frag->msg_header.type = s->d1->w_msg_hdr.type;
 991         frag->msg_header.frag_off = 0;
 992         frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
 993         frag->msg_header.is_ccs = is_ccs;
 994
 995         memset(seq64be,0,sizeof(seq64be));
 996         seq64be[0] = (unsigned char)(epoch>>8);
 997         seq64be[1] = (unsigned char)(epoch);
 998         seq64be[6] = (unsigned char)(frag->msg_header.seq>>8);
 999         seq64be[7] = (unsigned char)(frag->msg_header.seq);
1000
1001         item = pitem_new(seq64be, frag);
1002         if ( item == NULL)
1003                 {
1004                 dtls1_hm_fragment_free(frag);
1005                 return 0;
1006                 }
1007
1008 #if 0
1009         fprintf( stderr, "buffered messge: \ttype = %xx\n", msg_buf->type);
1010         fprintf( stderr, "\t\t\t\t\tlen = %d\n", msg_buf->len);
1011         fprintf( stderr, "\t\t\t\t\tseq_num = %d\n", msg_buf->seq_num);
1012 #endif
1013
1014         pqueue_insert(s->d1->sent_messages, item);
1015         return 1;
1016         }
1017
1018 int
1019 dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
1020         int *found)
1021         {
1022         int ret;
1023         /* XDTLS: for now assuming that read/writes are blocking */
1024         pitem *item;
1025         hm_fragment *frag ;
1026         unsigned long header_length;
1027         unsigned char seq64be[8];
1028
1029         /*
1030           OPENSSL_assert(s->init_num == 0);
1031           OPENSSL_assert(s->init_off == 0);
1032          */
1033
1034         /* XDTLS:  the requested message ought to be found, otherwise error */
1035         memset(seq64be,0,sizeof(seq64be));
1036         seq64be[6] = (unsigned char)(seq>>8);
1037         seq64be[7] = (unsigned char)seq;
1038
1039         item = pqueue_find(s->d1->sent_messages, seq64be);
1040         if ( item == NULL)
1041                 {
1042                 fprintf(stderr, "retransmit:  message %d non-existant\n", seq);
1043                 *found = 0;
1044                 return 0;
1045                 }
1046
1047         *found = 1;
1048         frag = (hm_fragment *)item->data;
1049
1050         if ( frag->msg_header.is_ccs)
1051                 header_length = DTLS1_CCS_HEADER_LENGTH;
1052         else
1053                 header_length = DTLS1_HM_HEADER_LENGTH;
1054
1055         memcpy(s->init_buf->data, frag->fragment,
1056                 frag->msg_header.msg_len + header_length);
1057                 s->init_num = frag->msg_header.msg_len + header_length;
1058
1059         dtls1_set_message_header_int(s, frag->msg_header.type,
1060                 frag->msg_header.msg_len, frag->msg_header.seq, 0,
1061                 frag->msg_header.frag_len);
1062
1063         s->d1->retransmitting = 1;
1064         ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1065                 SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1066         s->d1->retransmitting = 0;
1067
1068         (void)BIO_flush(SSL_get_wbio(s));
1069         return ret;
1070         }
1071
1072 /* call this function when the buffered messages are no longer needed */
1073 void
1074 dtls1_clear_record_buffer(SSL *s)
1075         {
1076         pitem *item;
1077
1078         for(item = pqueue_pop(s->d1->sent_messages);
1079                 item != NULL; item = pqueue_pop(s->d1->sent_messages))
1080                 {
1081                 dtls1_hm_fragment_free((hm_fragment *)item->data);
1082                 pitem_free(item);
1083                 }
1084         }
1085
1086
1087 unsigned char *
1088 dtls1_set_message_header(SSL *s, unsigned char *p, unsigned char mt,
1089                         unsigned long len, unsigned long frag_off, unsigned long frag_len)
1090         {
1091         if ( frag_off == 0)
1092                 {
1093                 s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1094                 s->d1->next_handshake_write_seq++;
1095                 }
1096
1097         dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1098                 frag_off, frag_len);
1099
1100         return p += DTLS1_HM_HEADER_LENGTH;
1101         }
1102
1103
1104 /* don't actually do the writing, wait till the MTU has been retrieved */
1105 static void
1106 dtls1_set_message_header_int(SSL *s, unsigned char mt,
1107                             unsigned long len, unsigned short seq_num, unsigned long frag_off,
1108                             unsigned long frag_len)
1109         {
1110         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1111
1112         msg_hdr->type = mt;
1113         msg_hdr->msg_len = len;
1114         msg_hdr->seq = seq_num;
1115         msg_hdr->frag_off = frag_off;
1116         msg_hdr->frag_len = frag_len;
1117         }
1118
1119 static void
1120 dtls1_fix_message_header(SSL *s, unsigned long frag_off,
1121                         unsigned long frag_len)
1122         {
1123         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1124
1125         msg_hdr->frag_off = frag_off;
1126         msg_hdr->frag_len = frag_len;
1127         }
1128
1129 static unsigned char *
1130 dtls1_write_message_header(SSL *s, unsigned char *p)
1131         {
1132         struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1133
1134         *p++ = msg_hdr->type;
1135         l2n3(msg_hdr->msg_len, p);
1136
1137         s2n(msg_hdr->seq, p);
1138         l2n3(msg_hdr->frag_off, p);
1139         l2n3(msg_hdr->frag_len, p);
1140
1141         return p;
1142         }
1143
1144 static unsigned int
1145 dtls1_min_mtu(void)
1146         {
1147         return (g_probable_mtu[(sizeof(g_probable_mtu) /
1148                 sizeof(g_probable_mtu[0])) - 1]);
1149         }
1150
1151 static unsigned int
1152 dtls1_guess_mtu(unsigned int curr_mtu)
1153         {
1154         unsigned int i;
1155
1156         if ( curr_mtu == 0 )
1157                 return g_probable_mtu[0] ;
1158
1159         for ( i = 0; i < sizeof(g_probable_mtu)/sizeof(g_probable_mtu[0]); i++)
1160                 if ( curr_mtu > g_probable_mtu[i])
1161                         return g_probable_mtu[i];
1162
1163         return curr_mtu;
1164         }
1165
1166 void
1167 dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
1168         {
1169         memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
1170         msg_hdr->type = *(data++);
1171         n2l3(data, msg_hdr->msg_len);
1172
1173         n2s(data, msg_hdr->seq);
1174         n2l3(data, msg_hdr->frag_off);
1175         n2l3(data, msg_hdr->frag_len);
1176         }
1177
1178 void
1179 dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st *ccs_hdr)
1180         {
1181         memset(ccs_hdr, 0x00, sizeof(struct ccs_header_st));
1182
1183         ccs_hdr->type = *(data++);
1184         }