ssl/d1_pkt.c

   1 /* ssl/d1_pkt.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 <stdio.h>
 117 #include <errno.h>
 118 #define USE_SOCKETS
 119 #include "ssl_locl.h"
 120 #include <openssl/evp.h>
 121 #include <openssl/buffer.h>
 122 #include <openssl/pqueue.h>
 123 #include <openssl/rand.h>
 124
 125 /* mod 128 saturating subtract of two 64-bit values in big-endian order */
 126 static int satsub64be(const unsigned char *v1,const unsigned char *v2)
 127 {       int ret,sat,brw,i;
 128
 129         if (sizeof(long) == 8) do
 130         {       const union { long one; char little; } is_endian = {1};
 131                 long l;
 132
 133                 if (is_endian.little)                   break;
 134                 /* not reached on little-endians */
 135                 /* following test is redundant, because input is
 136                  * always aligned, but I take no chances... */
 137                 if (((size_t)v1|(size_t)v2)&0x7)        break;
 138
 139                 l  = *((long *)v1);
 140                 l -= *((long *)v2);
 141                 if (l>128)              return 128;
 142                 else if (l<-128)        return -128;
 143                 else                    return (int)l;
 144         } while (0);
 145
 146         ret = (int)v1[7]-(int)v2[7];
 147         sat = 0;
 148         brw = ret>>8;   /* brw is either 0 or -1 */
 149         if (ret & 0x80)
 150         {       for (i=6;i>=0;i--)
 151                 {       brw += (int)v1[i]-(int)v2[i];
 152                         sat |= ~brw;
 153                         brw >>= 8;
 154                 }
 155         }
 156         else
 157         {       for (i=6;i>=0;i--)
 158                 {       brw += (int)v1[i]-(int)v2[i];
 159                         sat |= brw;
 160                         brw >>= 8;
 161                 }
 162         }
 163         brw <<= 8;      /* brw is either 0 or -256 */
 164
 165         if (sat&0xff)   return brw | 0x80;
 166         else            return brw + (ret&0xFF);
 167 }
 168
 169 static int have_handshake_fragment(SSL *s, int type, unsigned char *buf,
 170         int len, int peek);
 171 static int dtls1_record_replay_check(SSL *s, DTLS1_BITMAP *bitmap);
 172 static void dtls1_record_bitmap_update(SSL *s, DTLS1_BITMAP *bitmap);
 173 static DTLS1_BITMAP *dtls1_get_bitmap(SSL *s, SSL3_RECORD *rr,
 174     unsigned int *is_next_epoch);
 175 #if 0
 176 static int dtls1_record_needs_buffering(SSL *s, SSL3_RECORD *rr,
 177         unsigned short *priority, unsigned long *offset);
 178 #endif
 179 static int dtls1_buffer_record(SSL *s, record_pqueue *q,
 180         unsigned char *priority);
 181 static int dtls1_process_record(SSL *s);
 182 static void dtls1_clear_timeouts(SSL *s);
 183
 184 /* copy buffered record into SSL structure */
 185 static int
 186 dtls1_copy_record(SSL *s, pitem *item)
 187     {
 188     DTLS1_RECORD_DATA *rdata;
 189
 190     rdata = (DTLS1_RECORD_DATA *)item->data;
 191
 192     if (s->s3->rbuf.buf != NULL)
 193         OPENSSL_free(s->s3->rbuf.buf);
 194
 195     s->packet = rdata->packet;
 196     s->packet_length = rdata->packet_length;
 197     memcpy(&(s->s3->rbuf), &(rdata->rbuf), sizeof(SSL3_BUFFER));
 198     memcpy(&(s->s3->rrec), &(rdata->rrec), sizeof(SSL3_RECORD));
 199
 200     return(1);
 201     }
 202
 203
 204 static int
 205 dtls1_buffer_record(SSL *s, record_pqueue *queue, unsigned char *priority)
 206         {
 207         DTLS1_RECORD_DATA *rdata;
 208         pitem *item;
 209
 210         /* Limit the size of the queue to prevent DOS attacks */
 211         if (pqueue_size(queue->q) >= 100)
 212                 return 0;
 213
 214         rdata = OPENSSL_malloc(sizeof(DTLS1_RECORD_DATA));
 215         item = pitem_new(priority, rdata);
 216         if (rdata == NULL || item == NULL)
 217                 {
 218                 if (rdata != NULL) OPENSSL_free(rdata);
 219                 if (item != NULL) pitem_free(item);
 220
 221                 SSLerr(SSL_F_DTLS1_BUFFER_RECORD, ERR_R_INTERNAL_ERROR);
 222                 return(0);
 223                 }
 224
 225         rdata->packet = s->packet;
 226         rdata->packet_length = s->packet_length;
 227         memcpy(&(rdata->rbuf), &(s->s3->rbuf), sizeof(SSL3_BUFFER));
 228         memcpy(&(rdata->rrec), &(s->s3->rrec), sizeof(SSL3_RECORD));
 229
 230         item->data = rdata;
 231
 232         /* insert should not fail, since duplicates are dropped */
 233         if (pqueue_insert(queue->q, item) == NULL)
 234                 {
 235                 OPENSSL_free(rdata);
 236                 pitem_free(item);
 237                 return(0);
 238                 }
 239
 240         s->packet = NULL;
 241         s->packet_length = 0;
 242         memset(&(s->s3->rbuf), 0, sizeof(SSL3_BUFFER));
 243         memset(&(s->s3->rrec), 0, sizeof(SSL3_RECORD));
 244
 245         if (!ssl3_setup_buffers(s))
 246                 {
 247                 SSLerr(SSL_F_DTLS1_BUFFER_RECORD, ERR_R_INTERNAL_ERROR);
 248                 OPENSSL_free(rdata);
 249                 pitem_free(item);
 250                 return(0);
 251                 }
 252
 253         return(1);
 254         }
 255
 256
 257 static int
 258 dtls1_retrieve_buffered_record(SSL *s, record_pqueue *queue)
 259     {
 260     pitem *item;
 261
 262     item = pqueue_pop(queue->q);
 263     if (item)
 264         {
 265         dtls1_copy_record(s, item);
 266
 267         OPENSSL_free(item->data);
 268                 pitem_free(item);
 269
 270         return(1);
 271         }
 272
 273     return(0);
 274     }
 275
 276
 277 /* retrieve a buffered record that belongs to the new epoch, i.e., not processed
 278  * yet */
 279 #define dtls1_get_unprocessed_record(s) \
 280                    dtls1_retrieve_buffered_record((s), \
 281                    &((s)->d1->unprocessed_rcds))
 282
 283 /* retrieve a buffered record that belongs to the current epoch, ie, processed */
 284 #define dtls1_get_processed_record(s) \
 285                    dtls1_retrieve_buffered_record((s), \
 286                    &((s)->d1->processed_rcds))
 287
 288 static int
 289 dtls1_process_buffered_records(SSL *s)
 290     {
 291     pitem *item;
 292
 293     item = pqueue_peek(s->d1->unprocessed_rcds.q);
 294     if (item)
 295         {
 296         DTLS1_RECORD_DATA *rdata;
 297         rdata = (DTLS1_RECORD_DATA *)item->data;
 298
 299         /* Check if epoch is current. */
 300         if (s->d1->unprocessed_rcds.epoch != s->d1->r_epoch)
 301             return(1);  /* Nothing to do. */
 302
 303         /* Process all the records. */
 304         while (pqueue_peek(s->d1->unprocessed_rcds.q))
 305             {
 306             dtls1_get_unprocessed_record(s);
 307             if ( ! dtls1_process_record(s))
 308                 return(0);
 309             dtls1_buffer_record(s, &(s->d1->processed_rcds),
 310                 s->s3->rrec.seq_num);
 311             }
 312         }
 313
 314     /* sync epoch numbers once all the unprocessed records
 315      * have been processed */
 316     s->d1->processed_rcds.epoch = s->d1->r_epoch;
 317     s->d1->unprocessed_rcds.epoch = s->d1->r_epoch + 1;
 318
 319     return(1);
 320     }
 321
 322
 323 #if 0
 324
 325 static int
 326 dtls1_get_buffered_record(SSL *s)
 327         {
 328         pitem *item;
 329         PQ_64BIT priority =
 330                 (((PQ_64BIT)s->d1->handshake_read_seq) << 32) |
 331                 ((PQ_64BIT)s->d1->r_msg_hdr.frag_off);
 332
 333         if ( ! SSL_in_init(s))  /* if we're not (re)negotiating,
 334                                                            nothing buffered */
 335                 return 0;
 336
 337
 338         item = pqueue_peek(s->d1->rcvd_records);
 339         if (item && item->priority == priority)
 340                 {
 341                 /* Check if we've received the record of interest.  It must be
 342                  * a handshake record, since data records as passed up without
 343                  * buffering */
 344                 DTLS1_RECORD_DATA *rdata;
 345                 item = pqueue_pop(s->d1->rcvd_records);
 346                 rdata = (DTLS1_RECORD_DATA *)item->data;
 347
 348                 if (s->s3->rbuf.buf != NULL)
 349                         OPENSSL_free(s->s3->rbuf.buf);
 350
 351                 s->packet = rdata->packet;
 352                 s->packet_length = rdata->packet_length;
 353                 memcpy(&(s->s3->rbuf), &(rdata->rbuf), sizeof(SSL3_BUFFER));
 354                 memcpy(&(s->s3->rrec), &(rdata->rrec), sizeof(SSL3_RECORD));
 355
 356                 OPENSSL_free(item->data);
 357                 pitem_free(item);
 358
 359                 /* s->d1->next_expected_seq_num++; */
 360                 return(1);
 361                 }
 362
 363         return 0;
 364         }
 365
 366 #endif
 367
 368 static int
 369 dtls1_process_record(SSL *s)
 370 {
 371         int i,al;
 372         int clear=0;
 373         int enc_err;
 374         SSL_SESSION *sess;
 375         SSL3_RECORD *rr;
 376         unsigned int mac_size;
 377         unsigned char md[EVP_MAX_MD_SIZE];
 378
 379
 380         rr= &(s->s3->rrec);
 381         sess = s->session;
 382
 383         /* At this point, s->packet_length == SSL3_RT_HEADER_LNGTH + rr->length,
 384          * and we have that many bytes in s->packet
 385          */
 386         rr->input= &(s->packet[DTLS1_RT_HEADER_LENGTH]);
 387
 388         /* ok, we can now read from 's->packet' data into 'rr'
 389          * rr->input points at rr->length bytes, which
 390          * need to be copied into rr->data by either
 391          * the decryption or by the decompression
 392          * When the data is 'copied' into the rr->data buffer,
 393          * rr->input will be pointed at the new buffer */
 394
 395         /* We now have - encrypted [ MAC [ compressed [ plain ] ] ]
 396          * rr->length bytes of encrypted compressed stuff. */
 397
 398         /* check is not needed I believe */
 399         if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH)
 400                 {
 401                 al=SSL_AD_RECORD_OVERFLOW;
 402                 SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
 403                 goto f_err;
 404                 }
 405
 406         /* decrypt in place in 'rr->input' */
 407         rr->data=rr->input;
 408
 409         enc_err = s->method->ssl3_enc->enc(s,0);
 410         if (enc_err <= 0)
 411                 {
 412                 if (enc_err == 0)
 413                         /* SSLerr() and ssl3_send_alert() have been called */
 414                         goto err;
 415
 416                 /* otherwise enc_err == -1 */
 417                 goto decryption_failed_or_bad_record_mac;
 418                 }
 419
 420 #ifdef TLS_DEBUG
 421 printf("dec %d\n",rr->length);
 422 { unsigned int z; for (z=0; z<rr->length; z++) printf("%02X%c",rr->data[z],((z+1)%16)?' ':'\n'); }
 423 printf("\n");
 424 #endif
 425
 426         /* r->length is now the compressed data plus mac */
 427         if (    (sess == NULL) ||
 428                 (s->enc_read_ctx == NULL) ||
 429                 (s->read_hash == NULL))
 430                 clear=1;
 431
 432         if (!clear)
 433                 {
 434                 /* !clear => s->read_hash != NULL => mac_size != -1 */
 435                 int t;
 436                 t=EVP_MD_CTX_size(s->read_hash);
 437                 OPENSSL_assert(t >= 0);
 438                 mac_size=t;
 439
 440                 if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+mac_size)
 441                         {
 442 #if 0 /* OK only for stream ciphers (then rr->length is visible from ciphertext anyway) */
 443                         al=SSL_AD_RECORD_OVERFLOW;
 444                         SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_PRE_MAC_LENGTH_TOO_LONG);
 445                         goto f_err;
 446 #else
 447                         goto decryption_failed_or_bad_record_mac;
 448 #endif
 449                         }
 450                 /* check the MAC for rr->input (it's in mac_size bytes at the tail) */
 451                 if (rr->length < mac_size)
 452                         {
 453 #if 0 /* OK only for stream ciphers */
 454                         al=SSL_AD_DECODE_ERROR;
 455                         SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_LENGTH_TOO_SHORT);
 456                         goto f_err;
 457 #else
 458                         goto decryption_failed_or_bad_record_mac;
 459 #endif
 460                         }
 461                 rr->length-=mac_size;
 462                 i=s->method->ssl3_enc->mac(s,md,0);
 463                 if (i < 0 || memcmp(md,&(rr->data[rr->length]),mac_size) != 0)
 464                         {
 465                         goto decryption_failed_or_bad_record_mac;
 466                         }
 467                 }
 468
 469         /* r->length is now just compressed */
 470         if (s->expand != NULL)
 471                 {
 472                 if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH)
 473                         {
 474                         al=SSL_AD_RECORD_OVERFLOW;
 475                         SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_COMPRESSED_LENGTH_TOO_LONG);
 476                         goto f_err;
 477                         }
 478                 if (!ssl3_do_uncompress(s))
 479                         {
 480                         al=SSL_AD_DECOMPRESSION_FAILURE;
 481                         SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_BAD_DECOMPRESSION);
 482                         goto f_err;
 483                         }
 484                 }
 485
 486         if (rr->length > SSL3_RT_MAX_PLAIN_LENGTH)
 487                 {
 488                 al=SSL_AD_RECORD_OVERFLOW;
 489                 SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_DATA_LENGTH_TOO_LONG);
 490                 goto f_err;
 491                 }
 492
 493         rr->off=0;
 494         /* So at this point the following is true
 495          * ssl->s3->rrec.type   is the type of record
 496          * ssl->s3->rrec.length == number of bytes in record
 497          * ssl->s3->rrec.off    == offset to first valid byte
 498          * ssl->s3->rrec.data   == where to take bytes from, increment
 499          *                         after use :-).
 500          */
 501
 502         /* we have pulled in a full packet so zero things */
 503         s->packet_length=0;
 504         dtls1_record_bitmap_update(s, &(s->d1->bitmap));/* Mark receipt of record. */
 505         return(1);
 506
 507 decryption_failed_or_bad_record_mac:
 508         /* Separate 'decryption_failed' alert was introduced with TLS 1.0,
 509          * SSL 3.0 only has 'bad_record_mac'.  But unless a decryption
 510          * failure is directly visible from the ciphertext anyway,
 511          * we should not reveal which kind of error occured -- this
 512          * might become visible to an attacker (e.g. via logfile) */
 513         al=SSL_AD_BAD_RECORD_MAC;
 514         SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
 515 f_err:
 516         ssl3_send_alert(s,SSL3_AL_FATAL,al);
 517 err:
 518         return(0);
 519 }
 520
 521
 522 /* Call this to get a new input record.
 523  * It will return <= 0 if more data is needed, normally due to an error
 524  * or non-blocking IO.
 525  * When it finishes, one packet has been decoded and can be found in
 526  * ssl->s3->rrec.type    - is the type of record
 527  * ssl->s3->rrec.data,   - data
 528  * ssl->s3->rrec.length, - number of bytes
 529  */
 530 /* used only by dtls1_read_bytes */
 531 int dtls1_get_record(SSL *s)
 532         {
 533         int ssl_major,ssl_minor;
 534         int i,n;
 535         SSL3_RECORD *rr;
 536         SSL_SESSION *sess;
 537         unsigned char *p;
 538         unsigned short version;
 539         DTLS1_BITMAP *bitmap;
 540         unsigned int is_next_epoch;
 541
 542         rr= &(s->s3->rrec);
 543         sess=s->session;
 544
 545         /* The epoch may have changed.  If so, process all the
 546          * pending records.  This is a non-blocking operation. */
 547         if ( ! dtls1_process_buffered_records(s))
 548             return 0;
 549
 550         /* if we're renegotiating, then there may be buffered records */
 551         if (dtls1_get_processed_record(s))
 552                 return 1;
 553
 554         /* get something from the wire */
 555 again:
 556         /* check if we have the header */
 557         if (    (s->rstate != SSL_ST_READ_BODY) ||
 558                 (s->packet_length < DTLS1_RT_HEADER_LENGTH))
 559                 {
 560                 n=ssl3_read_n(s, DTLS1_RT_HEADER_LENGTH, s->s3->rbuf.len, 0);
 561                 /* read timeout is handled by dtls1_read_bytes */
 562                 if (n <= 0) return(n); /* error or non-blocking */
 563
 564                 /* this packet contained a partial record, dump it */
 565                 if (s->packet_length != DTLS1_RT_HEADER_LENGTH)
 566                         {
 567                         s->packet_length = 0;
 568                         goto again;
 569                         }
 570
 571                 s->rstate=SSL_ST_READ_BODY;
 572
 573                 p=s->packet;
 574
 575                 /* Pull apart the header into the DTLS1_RECORD */
 576                 rr->type= *(p++);
 577                 ssl_major= *(p++);
 578                 ssl_minor= *(p++);
 579                 version=(ssl_major<<8)|ssl_minor;
 580
 581                 /* sequence number is 64 bits, with top 2 bytes = epoch */
 582                 n2s(p,rr->epoch);
 583
 584                 memcpy(&(s->s3->read_sequence[2]), p, 6);
 585                 p+=6;
 586
 587                 n2s(p,rr->length);
 588
 589                 /* Lets check version */
 590                 if (!s->first_packet)
 591                         {
 592                         if (version != s->version)
 593                                 {
 594                                 /* unexpected version, silently discard */
 595                                 rr->length = 0;
 596                                 s->packet_length = 0;
 597                                 goto again;
 598                                 }
 599                         }
 600
 601                 if ((version & 0xff00) != (s->version & 0xff00))
 602                         {
 603                         /* wrong version, silently discard record */
 604                         rr->length = 0;
 605                         s->packet_length = 0;
 606                         goto again;
 607                         }
 608
 609                 if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH)
 610                         {
 611                         /* record too long, silently discard it */
 612                         rr->length = 0;
 613                         s->packet_length = 0;
 614                         goto again;
 615                         }
 616
 617                 /* now s->rstate == SSL_ST_READ_BODY */
 618                 }
 619
 620         /* s->rstate == SSL_ST_READ_BODY, get and decode the data */
 621
 622         if (rr->length > s->packet_length-DTLS1_RT_HEADER_LENGTH)
 623                 {
 624                 /* now s->packet_length == DTLS1_RT_HEADER_LENGTH */
 625                 i=rr->length;
 626                 n=ssl3_read_n(s,i,i,1);
 627                 if (n <= 0) return(n); /* error or non-blocking io */
 628
 629                 /* this packet contained a partial record, dump it */
 630                 if ( n != i)
 631                         {
 632                         rr->length = 0;
 633                         s->packet_length = 0;
 634                         goto again;
 635                         }
 636
 637                 /* now n == rr->length,
 638                  * and s->packet_length == DTLS1_RT_HEADER_LENGTH + rr->length */
 639                 }
 640         s->rstate=SSL_ST_READ_HEADER; /* set state for later operations */
 641
 642         /* match epochs.  NULL means the packet is dropped on the floor */
 643         bitmap = dtls1_get_bitmap(s, rr, &is_next_epoch);
 644         if ( bitmap == NULL)
 645                 {
 646                 rr->length = 0;
 647                 s->packet_length = 0;  /* dump this record */
 648                 goto again;   /* get another record */
 649                 }
 650
 651         /* check whether this is a repeat, or aged record */
 652         if ( ! dtls1_record_replay_check(s, bitmap))
 653                 {
 654                 rr->length = 0;
 655                 s->packet_length=0; /* dump this record */
 656                 goto again;     /* get another record */
 657                 }
 658
 659         /* just read a 0 length packet */
 660         if (rr->length == 0) goto again;
 661
 662         /* If this record is from the next epoch (either HM or ALERT),
 663          * buffer it since it cannot be processed at this time. Records
 664          * from the next epoch are marked as received even though they
 665          * are not processed, so as to prevent any potential resource
 666          * DoS attack */
 667         if (is_next_epoch)
 668                 {
 669                 dtls1_record_bitmap_update(s, bitmap);
 670                 dtls1_buffer_record(s, &(s->d1->unprocessed_rcds), rr->seq_num);
 671                 rr->length = 0;
 672                 s->packet_length = 0;
 673                 goto again;
 674                 }
 675
 676         if ( ! dtls1_process_record(s))
 677                 return(0);
 678
 679         dtls1_clear_timeouts(s);  /* done waiting */
 680         return(1);
 681
 682         }
 683
 684 /* Return up to 'len' payload bytes received in 'type' records.
 685  * 'type' is one of the following:
 686  *
 687  *   -  SSL3_RT_HANDSHAKE (when ssl3_get_message calls us)
 688  *   -  SSL3_RT_APPLICATION_DATA (when ssl3_read calls us)
 689  *   -  0 (during a shutdown, no data has to be returned)
 690  *
 691  * If we don't have stored data to work from, read a SSL/TLS record first
 692  * (possibly multiple records if we still don't have anything to return).
 693  *
 694  * This function must handle any surprises the peer may have for us, such as
 695  * Alert records (e.g. close_notify), ChangeCipherSpec records (not really
 696  * a surprise, but handled as if it were), or renegotiation requests.
 697  * Also if record payloads contain fragments too small to process, we store
 698  * them until there is enough for the respective protocol (the record protocol
 699  * may use arbitrary fragmentation and even interleaving):
 700  *     Change cipher spec protocol
 701  *             just 1 byte needed, no need for keeping anything stored
 702  *     Alert protocol
 703  *             2 bytes needed (AlertLevel, AlertDescription)
 704  *     Handshake protocol
 705  *             4 bytes needed (HandshakeType, uint24 length) -- we just have
 706  *             to detect unexpected Client Hello and Hello Request messages
 707  *             here, anything else is handled by higher layers
 708  *     Application data protocol
 709  *             none of our business
 710  */
 711 int dtls1_read_bytes(SSL *s, int type, unsigned char *buf, int len, int peek)
 712         {
 713         int al,i,j,ret;
 714         unsigned int n;
 715         SSL3_RECORD *rr;
 716         void (*cb)(const SSL *ssl,int type2,int val)=NULL;
 717
 718         if (s->s3->rbuf.buf == NULL) /* Not initialized yet */
 719                 if (!ssl3_setup_buffers(s))
 720                         return(-1);
 721
 722     /* XXX: check what the second '&& type' is about */
 723         if ((type && (type != SSL3_RT_APPLICATION_DATA) &&
 724                 (type != SSL3_RT_HANDSHAKE) && type) ||
 725             (peek && (type != SSL3_RT_APPLICATION_DATA)))
 726                 {
 727                 SSLerr(SSL_F_DTLS1_READ_BYTES, ERR_R_INTERNAL_ERROR);
 728                 return -1;
 729                 }
 730
 731         /* check whether there's a handshake message (client hello?) waiting */
 732         if ( (ret = have_handshake_fragment(s, type, buf, len, peek)))
 733                 return ret;
 734
 735         /* Now s->d1->handshake_fragment_len == 0 if type == SSL3_RT_HANDSHAKE. */
 736
 737         if (!s->in_handshake && SSL_in_init(s))
 738                 {
 739                 /* type == SSL3_RT_APPLICATION_DATA */
 740                 i=s->handshake_func(s);
 741                 if (i < 0) return(i);
 742                 if (i == 0)
 743                         {
 744                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
 745                         return(-1);
 746                         }
 747                 }
 748
 749 start:
 750         s->rwstate=SSL_NOTHING;
 751
 752         /* s->s3->rrec.type         - is the type of record
 753          * s->s3->rrec.data,    - data
 754          * s->s3->rrec.off,     - offset into 'data' for next read
 755          * s->s3->rrec.length,  - number of bytes. */
 756         rr = &(s->s3->rrec);
 757
 758         /* We are not handshaking and have no data yet,
 759          * so process data buffered during the last handshake
 760          * in advance, if any.
 761          */
 762         if (s->state == SSL_ST_OK && rr->length == 0)
 763                 {
 764                 pitem *item;
 765                 item = pqueue_pop(s->d1->buffered_app_data.q);
 766                 if (item)
 767                         {
 768                         dtls1_copy_record(s, item);
 769
 770                         OPENSSL_free(item->data);
 771                         pitem_free(item);
 772                         }
 773                 }
 774
 775         /* Check for timeout */
 776         if (dtls1_handle_timeout(s) > 0)
 777                 goto start;
 778
 779         /* get new packet if necessary */
 780         if ((rr->length == 0) || (s->rstate == SSL_ST_READ_BODY))
 781                 {
 782                 ret=dtls1_get_record(s);
 783                 if (ret <= 0)
 784                         {
 785                         ret = dtls1_read_failed(s, ret);
 786                         /* anything other than a timeout is an error */
 787                         if (ret <= 0)
 788                                 return(ret);
 789                         else
 790                                 goto start;
 791                         }
 792                 }
 793
 794         /* we now have a packet which can be read and processed */
 795
 796         if (s->s3->change_cipher_spec /* set when we receive ChangeCipherSpec,
 797                                        * reset by ssl3_get_finished */
 798                 && (rr->type != SSL3_RT_HANDSHAKE))
 799                 {
 800                 /* We now have application data between CCS and Finished.
 801                  * Most likely the packets were reordered on their way, so
 802                  * buffer the application data for later processing rather
 803                  * than dropping the connection.
 804                  */
 805                 dtls1_buffer_record(s, &(s->d1->buffered_app_data), 0);
 806                 rr->length = 0;
 807                 goto start;
 808                 }
 809
 810         /* If the other end has shut down, throw anything we read away
 811          * (even in 'peek' mode) */
 812         if (s->shutdown & SSL_RECEIVED_SHUTDOWN)
 813                 {
 814                 rr->length=0;
 815                 s->rwstate=SSL_NOTHING;
 816                 return(0);
 817                 }
 818
 819
 820         if (type == rr->type) /* SSL3_RT_APPLICATION_DATA or SSL3_RT_HANDSHAKE */
 821                 {
 822                 /* make sure that we are not getting application data when we
 823                  * are doing a handshake for the first time */
 824                 if (SSL_in_init(s) && (type == SSL3_RT_APPLICATION_DATA) &&
 825                         (s->enc_read_ctx == NULL))
 826                         {
 827                         al=SSL_AD_UNEXPECTED_MESSAGE;
 828                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_APP_DATA_IN_HANDSHAKE);
 829                         goto f_err;
 830                         }
 831
 832                 if (len <= 0) return(len);
 833
 834                 if ((unsigned int)len > rr->length)
 835                         n = rr->length;
 836                 else
 837                         n = (unsigned int)len;
 838
 839                 memcpy(buf,&(rr->data[rr->off]),n);
 840                 if (!peek)
 841                         {
 842                         rr->length-=n;
 843                         rr->off+=n;
 844                         if (rr->length == 0)
 845                                 {
 846                                 s->rstate=SSL_ST_READ_HEADER;
 847                                 rr->off=0;
 848                                 }
 849                         }
 850                 return(n);
 851                 }
 852
 853
 854         /* If we get here, then type != rr->type; if we have a handshake
 855          * message, then it was unexpected (Hello Request or Client Hello). */
 856
 857         /* In case of record types for which we have 'fragment' storage,
 858          * fill that so that we can process the data at a fixed place.
 859          */
 860                 {
 861                 unsigned int k, dest_maxlen = 0;
 862                 unsigned char *dest = NULL;
 863                 unsigned int *dest_len = NULL;
 864
 865                 if (rr->type == SSL3_RT_HANDSHAKE)
 866                         {
 867                         dest_maxlen = sizeof s->d1->handshake_fragment;
 868                         dest = s->d1->handshake_fragment;
 869                         dest_len = &s->d1->handshake_fragment_len;
 870                         }
 871                 else if (rr->type == SSL3_RT_ALERT)
 872                         {
 873                         dest_maxlen = sizeof(s->d1->alert_fragment);
 874                         dest = s->d1->alert_fragment;
 875                         dest_len = &s->d1->alert_fragment_len;
 876                         }
 877                 /* else it's a CCS message, or application data or wrong */
 878                 else if (rr->type != SSL3_RT_CHANGE_CIPHER_SPEC)
 879                         {
 880                         /* Application data while renegotiating
 881                          * is allowed. Try again reading.
 882                          */
 883                         if (rr->type == SSL3_RT_APPLICATION_DATA)
 884                                 {
 885                                 BIO *bio;
 886                                 s->s3->in_read_app_data=2;
 887                                 bio=SSL_get_rbio(s);
 888                                 s->rwstate=SSL_READING;
 889                                 BIO_clear_retry_flags(bio);
 890                                 BIO_set_retry_read(bio);
 891                                 return(-1);
 892                                 }
 893
 894                         /* Not certain if this is the right error handling */
 895                         al=SSL_AD_UNEXPECTED_MESSAGE;
 896                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_UNEXPECTED_RECORD);
 897                         goto f_err;
 898                         }
 899
 900                 if (dest_maxlen > 0)
 901                         {
 902             /* XDTLS:  In a pathalogical case, the Client Hello
 903              *  may be fragmented--don't always expect dest_maxlen bytes */
 904                         if ( rr->length < dest_maxlen)
 905                                 {
 906 #ifdef DTLS1_AD_MISSING_HANDSHAKE_MESSAGE
 907                                 /*
 908                                  * for normal alerts rr->length is 2, while
 909                                  * dest_maxlen is 7 if we were to handle this
 910                                  * non-existing alert...
 911                                  */
 912                                 FIX ME
 913 #endif
 914                                 s->rstate=SSL_ST_READ_HEADER;
 915                                 rr->length = 0;
 916                                 goto start;
 917                                 }
 918
 919                         /* now move 'n' bytes: */
 920                         for ( k = 0; k < dest_maxlen; k++)
 921                                 {
 922                                 dest[k] = rr->data[rr->off++];
 923                                 rr->length--;
 924                                 }
 925                         *dest_len = dest_maxlen;
 926                         }
 927                 }
 928
 929         /* s->d1->handshake_fragment_len == 12  iff  rr->type == SSL3_RT_HANDSHAKE;
 930          * s->d1->alert_fragment_len == 7      iff  rr->type == SSL3_RT_ALERT.
 931          * (Possibly rr is 'empty' now, i.e. rr->length may be 0.) */
 932
 933         /* If we are a client, check for an incoming 'Hello Request': */
 934         if ((!s->server) &&
 935                 (s->d1->handshake_fragment_len >= DTLS1_HM_HEADER_LENGTH) &&
 936                 (s->d1->handshake_fragment[0] == SSL3_MT_HELLO_REQUEST) &&
 937                 (s->session != NULL) && (s->session->cipher != NULL))
 938                 {
 939                 s->d1->handshake_fragment_len = 0;
 940
 941                 if ((s->d1->handshake_fragment[1] != 0) ||
 942                         (s->d1->handshake_fragment[2] != 0) ||
 943                         (s->d1->handshake_fragment[3] != 0))
 944                         {
 945                         al=SSL_AD_DECODE_ERROR;
 946                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_BAD_HELLO_REQUEST);
 947                         goto err;
 948                         }
 949
 950                 /* no need to check sequence number on HELLO REQUEST messages */
 951
 952                 if (s->msg_callback)
 953                         s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
 954                                 s->d1->handshake_fragment, 4, s, s->msg_callback_arg);
 955
 956                 if (SSL_is_init_finished(s) &&
 957                         !(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS) &&
 958                         !s->s3->renegotiate)
 959                         {
 960                         ssl3_renegotiate(s);
 961                         if (ssl3_renegotiate_check(s))
 962                                 {
 963                                 i=s->handshake_func(s);
 964                                 if (i < 0) return(i);
 965                                 if (i == 0)
 966                                         {
 967                                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
 968                                         return(-1);
 969                                         }
 970
 971                                 if (!(s->mode & SSL_MODE_AUTO_RETRY))
 972                                         {
 973                                         if (s->s3->rbuf.left == 0) /* no read-ahead left? */
 974                                                 {
 975                                                 BIO *bio;
 976                                                 /* In the case where we try to read application data,
 977                                                  * but we trigger an SSL handshake, we return -1 with
 978                                                  * the retry option set.  Otherwise renegotiation may
 979                                                  * cause nasty problems in the blocking world */
 980                                                 s->rwstate=SSL_READING;
 981                                                 bio=SSL_get_rbio(s);
 982                                                 BIO_clear_retry_flags(bio);
 983                                                 BIO_set_retry_read(bio);
 984                                                 return(-1);
 985                                                 }
 986                                         }
 987                                 }
 988                         }
 989                 /* we either finished a handshake or ignored the request,
 990                  * now try again to obtain the (application) data we were asked for */
 991                 goto start;
 992                 }
 993
 994         if (s->d1->alert_fragment_len >= DTLS1_AL_HEADER_LENGTH)
 995                 {
 996                 int alert_level = s->d1->alert_fragment[0];
 997                 int alert_descr = s->d1->alert_fragment[1];
 998
 999                 s->d1->alert_fragment_len = 0;
1000
1001                 if (s->msg_callback)
1002                         s->msg_callback(0, s->version, SSL3_RT_ALERT,
1003                                 s->d1->alert_fragment, 2, s, s->msg_callback_arg);
1004
1005                 if (s->info_callback != NULL)
1006                         cb=s->info_callback;
1007                 else if (s->ctx->info_callback != NULL)
1008                         cb=s->ctx->info_callback;
1009
1010                 if (cb != NULL)
1011                         {
1012                         j = (alert_level << 8) | alert_descr;
1013                         cb(s, SSL_CB_READ_ALERT, j);
1014                         }
1015
1016                 if (alert_level == 1) /* warning */
1017                         {
1018                         s->s3->warn_alert = alert_descr;
1019                         if (alert_descr == SSL_AD_CLOSE_NOTIFY)
1020                                 {
1021                                 s->shutdown |= SSL_RECEIVED_SHUTDOWN;
1022                                 return(0);
1023                                 }
1024 #if 0
1025             /* XXX: this is a possible improvement in the future */
1026                         /* now check if it's a missing record */
1027                         if (alert_descr == DTLS1_AD_MISSING_HANDSHAKE_MESSAGE)
1028                                 {
1029                                 unsigned short seq;
1030                                 unsigned int frag_off;
1031                                 unsigned char *p = &(s->d1->alert_fragment[2]);
1032
1033                                 n2s(p, seq);
1034                                 n2l3(p, frag_off);
1035
1036                                 dtls1_retransmit_message(s,
1037                                                                                  dtls1_get_queue_priority(frag->msg_header.seq, 0),
1038                                                                                  frag_off, &found);
1039                                 if ( ! found  && SSL_in_init(s))
1040                                         {
1041                                         /* fprintf( stderr,"in init = %d\n", SSL_in_init(s)); */
1042                                         /* requested a message not yet sent,
1043                                            send an alert ourselves */
1044                                         ssl3_send_alert(s,SSL3_AL_WARNING,
1045                                                 DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
1046                                         }
1047                                 }
1048 #endif
1049                         }
1050                 else if (alert_level == 2) /* fatal */
1051                         {
1052                         char tmp[16];
1053
1054                         s->rwstate=SSL_NOTHING;
1055                         s->s3->fatal_alert = alert_descr;
1056                         SSLerr(SSL_F_DTLS1_READ_BYTES, SSL_AD_REASON_OFFSET + alert_descr);
1057                         BIO_snprintf(tmp,sizeof tmp,"%d",alert_descr);
1058                         ERR_add_error_data(2,"SSL alert number ",tmp);
1059                         s->shutdown|=SSL_RECEIVED_SHUTDOWN;
1060                         SSL_CTX_remove_session(s->ctx,s->session);
1061                         return(0);
1062                         }
1063                 else
1064                         {
1065                         al=SSL_AD_ILLEGAL_PARAMETER;
1066                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_UNKNOWN_ALERT_TYPE);
1067                         goto f_err;
1068                         }
1069
1070                 goto start;
1071                 }
1072
1073         if (s->shutdown & SSL_SENT_SHUTDOWN) /* but we have not received a shutdown */
1074                 {
1075                 s->rwstate=SSL_NOTHING;
1076                 rr->length=0;
1077                 return(0);
1078                 }
1079
1080         if (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC)
1081                 {
1082                 struct ccs_header_st ccs_hdr;
1083                 unsigned int ccs_hdr_len = DTLS1_CCS_HEADER_LENGTH;
1084
1085                 dtls1_get_ccs_header(rr->data, &ccs_hdr);
1086
1087                 if (s->version == DTLS1_BAD_VER)
1088                         ccs_hdr_len = 3;
1089
1090                 /* 'Change Cipher Spec' is just a single byte, so we know
1091                  * exactly what the record payload has to look like */
1092                 /* XDTLS: check that epoch is consistent */
1093                 if (    (rr->length != ccs_hdr_len) ||
1094                         (rr->off != 0) || (rr->data[0] != SSL3_MT_CCS))
1095                         {
1096                         i=SSL_AD_ILLEGAL_PARAMETER;
1097                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_BAD_CHANGE_CIPHER_SPEC);
1098                         goto err;
1099                         }
1100
1101                 rr->length=0;
1102
1103                 if (s->msg_callback)
1104                         s->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC,
1105                                 rr->data, 1, s, s->msg_callback_arg);
1106
1107                 /* We can't process a CCS now, because previous handshake
1108                  * messages are still missing, so just drop it.
1109                  */
1110                 if (!s->d1->change_cipher_spec_ok)
1111                         {
1112                         goto start;
1113                         }
1114
1115                 s->d1->change_cipher_spec_ok = 0;
1116
1117                 s->s3->change_cipher_spec=1;
1118                 if (!ssl3_do_change_cipher_spec(s))
1119                         goto err;
1120
1121                 /* do this whenever CCS is processed */
1122                 dtls1_reset_seq_numbers(s, SSL3_CC_READ);
1123
1124                 if (s->version == DTLS1_BAD_VER)
1125                         s->d1->handshake_read_seq++;
1126
1127                 goto start;
1128                 }
1129
1130         /* Unexpected handshake message (Client Hello, or protocol violation) */
1131         if ((s->d1->handshake_fragment_len >= DTLS1_HM_HEADER_LENGTH) &&
1132                 !s->in_handshake)
1133                 {
1134                 struct hm_header_st msg_hdr;
1135
1136                 /* this may just be a stale retransmit */
1137                 dtls1_get_message_header(rr->data, &msg_hdr);
1138                 if( rr->epoch != s->d1->r_epoch)
1139                         {
1140                         rr->length = 0;
1141                         goto start;
1142                         }
1143
1144                 /* If we are server, we may have a repeated FINISHED of the
1145                  * client here, then retransmit our CCS and FINISHED.
1146                  */
1147                 if (msg_hdr.type == SSL3_MT_FINISHED)
1148                         {
1149                         dtls1_retransmit_buffered_messages(s);
1150                         rr->length = 0;
1151                         goto start;
1152                         }
1153
1154                 if (((s->state&SSL_ST_MASK) == SSL_ST_OK) &&
1155                         !(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS))
1156                         {
1157 #if 0 /* worked only because C operator preferences are not as expected (and
1158        * because this is not really needed for clients except for detecting
1159        * protocol violations): */
1160                         s->state=SSL_ST_BEFORE|(s->server)
1161                                 ?SSL_ST_ACCEPT
1162                                 :SSL_ST_CONNECT;
1163 #else
1164                         s->state = s->server ? SSL_ST_ACCEPT : SSL_ST_CONNECT;
1165 #endif
1166                         s->new_session=1;
1167                         }
1168                 i=s->handshake_func(s);
1169                 if (i < 0) return(i);
1170                 if (i == 0)
1171                         {
1172                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
1173                         return(-1);
1174                         }
1175
1176                 if (!(s->mode & SSL_MODE_AUTO_RETRY))
1177                         {
1178                         if (s->s3->rbuf.left == 0) /* no read-ahead left? */
1179                                 {
1180                                 BIO *bio;
1181                                 /* In the case where we try to read application data,
1182                                  * but we trigger an SSL handshake, we return -1 with
1183                                  * the retry option set.  Otherwise renegotiation may
1184                                  * cause nasty problems in the blocking world */
1185                                 s->rwstate=SSL_READING;
1186                                 bio=SSL_get_rbio(s);
1187                                 BIO_clear_retry_flags(bio);
1188                                 BIO_set_retry_read(bio);
1189                                 return(-1);
1190                                 }
1191                         }
1192                 goto start;
1193                 }
1194
1195         switch (rr->type)
1196                 {
1197         default:
1198 #ifndef OPENSSL_NO_TLS
1199                 /* TLS just ignores unknown message types */
1200                 if (s->version == TLS1_VERSION)
1201                         {
1202                         rr->length = 0;
1203                         goto start;
1204                         }
1205 #endif
1206                 al=SSL_AD_UNEXPECTED_MESSAGE;
1207                 SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_UNEXPECTED_RECORD);
1208                 goto f_err;
1209         case SSL3_RT_CHANGE_CIPHER_SPEC:
1210         case SSL3_RT_ALERT:
1211         case SSL3_RT_HANDSHAKE:
1212                 /* we already handled all of these, with the possible exception
1213                  * of SSL3_RT_HANDSHAKE when s->in_handshake is set, but that
1214                  * should not happen when type != rr->type */
1215                 al=SSL_AD_UNEXPECTED_MESSAGE;
1216                 SSLerr(SSL_F_DTLS1_READ_BYTES,ERR_R_INTERNAL_ERROR);
1217                 goto f_err;
1218         case SSL3_RT_APPLICATION_DATA:
1219                 /* At this point, we were expecting handshake data,
1220                  * but have application data.  If the library was
1221                  * running inside ssl3_read() (i.e. in_read_app_data
1222                  * is set) and it makes sense to read application data
1223                  * at this point (session renegotiation not yet started),
1224                  * we will indulge it.
1225                  */
1226                 if (s->s3->in_read_app_data &&
1227                         (s->s3->total_renegotiations != 0) &&
1228                         ((
1229                                 (s->state & SSL_ST_CONNECT) &&
1230                                 (s->state >= SSL3_ST_CW_CLNT_HELLO_A) &&
1231                                 (s->state <= SSL3_ST_CR_SRVR_HELLO_A)
1232                                 ) || (
1233                                         (s->state & SSL_ST_ACCEPT) &&
1234                                         (s->state <= SSL3_ST_SW_HELLO_REQ_A) &&
1235                                         (s->state >= SSL3_ST_SR_CLNT_HELLO_A)
1236                                         )
1237                                 ))
1238                         {
1239                         s->s3->in_read_app_data=2;
1240                         return(-1);
1241                         }
1242                 else
1243                         {
1244                         al=SSL_AD_UNEXPECTED_MESSAGE;
1245                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_UNEXPECTED_RECORD);
1246                         goto f_err;
1247                         }
1248                 }
1249         /* not reached */
1250
1251 f_err:
1252         ssl3_send_alert(s,SSL3_AL_FATAL,al);
1253 err:
1254         return(-1);
1255         }
1256
1257 int
1258 dtls1_write_app_data_bytes(SSL *s, int type, const void *buf_, int len)
1259         {
1260         unsigned int n,tot;
1261         int i;
1262
1263         if (SSL_in_init(s) && !s->in_handshake)
1264                 {
1265                 i=s->handshake_func(s);
1266                 if (i < 0) return(i);
1267                 if (i == 0)
1268                         {
1269                         SSLerr(SSL_F_DTLS1_WRITE_APP_DATA_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
1270                         return -1;
1271                         }
1272                 }
1273
1274         tot = s->s3->wnum;
1275         n = len - tot;
1276
1277         while( n)
1278                 {
1279                 /* dtls1_write_bytes sends one record at a time, sized according to
1280                  * the currently known MTU */
1281                 i = dtls1_write_bytes(s, type, buf_, len);
1282                 if (i <= 0) return i;
1283
1284                 if ((i == (int)n) ||
1285                         (type == SSL3_RT_APPLICATION_DATA &&
1286                                 (s->mode & SSL_MODE_ENABLE_PARTIAL_WRITE)))
1287                         {
1288                         /* next chunk of data should get another prepended empty fragment
1289                          * in ciphersuites with known-IV weakness: */
1290                         s->s3->empty_fragment_done = 0;
1291                         return tot+i;
1292                         }
1293
1294                 tot += i;
1295                 n-=i;
1296                 }
1297
1298         return tot;
1299         }
1300
1301
1302         /* this only happens when a client hello is received and a handshake
1303          * is started. */
1304 static int
1305 have_handshake_fragment(SSL *s, int type, unsigned char *buf,
1306         int len, int peek)
1307         {
1308
1309         if ((type == SSL3_RT_HANDSHAKE) && (s->d1->handshake_fragment_len > 0))
1310                 /* (partially) satisfy request from storage */
1311                 {
1312                 unsigned char *src = s->d1->handshake_fragment;
1313                 unsigned char *dst = buf;
1314                 unsigned int k,n;
1315
1316                 /* peek == 0 */
1317                 n = 0;
1318                 while ((len > 0) && (s->d1->handshake_fragment_len > 0))
1319                         {
1320                         *dst++ = *src++;
1321                         len--; s->d1->handshake_fragment_len--;
1322                         n++;
1323                         }
1324                 /* move any remaining fragment bytes: */
1325                 for (k = 0; k < s->d1->handshake_fragment_len; k++)
1326                         s->d1->handshake_fragment[k] = *src++;
1327                 return n;
1328                 }
1329
1330         return 0;
1331         }
1332
1333
1334
1335
1336 /* Call this to write data in records of type 'type'
1337  * It will return <= 0 if not all data has been sent or non-blocking IO.
1338  */
1339 int dtls1_write_bytes(SSL *s, int type, const void *buf_, int len)
1340         {
1341         const unsigned char *buf=buf_;
1342         unsigned int tot,n,nw;
1343         int i;
1344         unsigned int mtu;
1345
1346         s->rwstate=SSL_NOTHING;
1347         tot=s->s3->wnum;
1348
1349         n=(len-tot);
1350
1351         /* handshake layer figures out MTU for itself, but data records
1352          * are also sent through this interface, so need to figure out MTU */
1353 #if 0
1354         mtu = BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_MTU, 0, NULL);
1355         mtu += DTLS1_HM_HEADER_LENGTH;  /* HM already inserted */
1356 #endif
1357         mtu = s->d1->mtu;
1358
1359         if (mtu > SSL3_RT_MAX_PLAIN_LENGTH)
1360                 mtu = SSL3_RT_MAX_PLAIN_LENGTH;
1361
1362         if (n > mtu)
1363                 nw=mtu;
1364         else
1365                 nw=n;
1366
1367         i=do_dtls1_write(s, type, &(buf[tot]), nw, 0);
1368         if (i <= 0)
1369                 {
1370                 s->s3->wnum=tot;
1371                 return i;
1372                 }
1373
1374         if ( (int)s->s3->wnum + i == len)
1375                 s->s3->wnum = 0;
1376         else
1377                 s->s3->wnum += i;
1378
1379         return i;
1380         }
1381
1382 int do_dtls1_write(SSL *s, int type, const unsigned char *buf, unsigned int len, int create_empty_fragment)
1383         {
1384         unsigned char *p,*pseq;
1385         int i,mac_size,clear=0;
1386         int prefix_len = 0;
1387         SSL3_RECORD *wr;
1388         SSL3_BUFFER *wb;
1389         SSL_SESSION *sess;
1390         int bs;
1391
1392         /* first check if there is a SSL3_BUFFER still being written
1393          * out.  This will happen with non blocking IO */
1394         if (s->s3->wbuf.left != 0)
1395                 {
1396                 OPENSSL_assert(0); /* XDTLS:  want to see if we ever get here */
1397                 return(ssl3_write_pending(s,type,buf,len));
1398                 }
1399
1400         /* If we have an alert to send, lets send it */
1401         if (s->s3->alert_dispatch)
1402                 {
1403                 i=s->method->ssl_dispatch_alert(s);
1404                 if (i <= 0)
1405                         return(i);
1406                 /* if it went, fall through and send more stuff */
1407                 }
1408
1409         if (len == 0 && !create_empty_fragment)
1410                 return 0;
1411
1412         wr= &(s->s3->wrec);
1413         wb= &(s->s3->wbuf);
1414         sess=s->session;
1415
1416         if (    (sess == NULL) ||
1417                 (s->enc_write_ctx == NULL) ||
1418                 (EVP_MD_CTX_md(s->write_hash) == NULL))
1419                 clear=1;
1420
1421         if (clear)
1422                 mac_size=0;
1423         else
1424                 {
1425                 mac_size=EVP_MD_CTX_size(s->write_hash);
1426                 if (mac_size < 0)
1427                         goto err;
1428                 }
1429
1430         /* DTLS implements explicit IV, so no need for empty fragments */
1431 #if 0
1432         /* 'create_empty_fragment' is true only when this function calls itself */
1433         if (!clear && !create_empty_fragment && !s->s3->empty_fragment_done
1434             && SSL_version(s) != DTLS1_VERSION && SSL_version(s) != DTLS1_BAD_VER)
1435                 {
1436                 /* countermeasure against known-IV weakness in CBC ciphersuites
1437                  * (see http://www.openssl.org/~bodo/tls-cbc.txt)
1438                  */
1439
1440                 if (s->s3->need_empty_fragments && type == SSL3_RT_APPLICATION_DATA)
1441                         {
1442                         /* recursive function call with 'create_empty_fragment' set;
1443                          * this prepares and buffers the data for an empty fragment
1444                          * (these 'prefix_len' bytes are sent out later
1445                          * together with the actual payload) */
1446                         prefix_len = s->method->do_ssl_write(s, type, buf, 0, 1);
1447                         if (prefix_len <= 0)
1448                                 goto err;
1449
1450                         if (s->s3->wbuf.len < (size_t)prefix_len + SSL3_RT_MAX_PACKET_SIZE)
1451                                 {
1452                                 /* insufficient space */
1453                                 SSLerr(SSL_F_DO_DTLS1_WRITE, ERR_R_INTERNAL_ERROR);
1454                                 goto err;
1455                                 }
1456                         }
1457
1458                 s->s3->empty_fragment_done = 1;
1459                 }
1460 #endif
1461         p = wb->buf + prefix_len;
1462
1463         /* write the header */
1464
1465         *(p++)=type&0xff;
1466         wr->type=type;
1467
1468         *(p++)=(s->version>>8);
1469         *(p++)=s->version&0xff;
1470
1471         /* field where we are to write out packet epoch, seq num and len */
1472         pseq=p;
1473         p+=10;
1474
1475         /* lets setup the record stuff. */
1476
1477         /* Make space for the explicit IV in case of CBC.
1478          * (this is a bit of a boundary violation, but what the heck).
1479          */
1480         if ( s->enc_write_ctx &&
1481                 (EVP_CIPHER_mode( s->enc_write_ctx->cipher ) & EVP_CIPH_CBC_MODE))
1482                 bs = EVP_CIPHER_block_size(s->enc_write_ctx->cipher);
1483         else
1484                 bs = 0;
1485
1486         wr->data=p + bs;  /* make room for IV in case of CBC */
1487         wr->length=(int)len;
1488         wr->input=(unsigned char *)buf;
1489
1490         /* we now 'read' from wr->input, wr->length bytes into
1491          * wr->data */
1492
1493         /* first we compress */
1494         if (s->compress != NULL)
1495                 {
1496                 if (!ssl3_do_compress(s))
1497                         {
1498                         SSLerr(SSL_F_DO_DTLS1_WRITE,SSL_R_COMPRESSION_FAILURE);
1499                         goto err;
1500                         }
1501                 }
1502         else
1503                 {
1504                 memcpy(wr->data,wr->input,wr->length);
1505                 wr->input=wr->data;
1506                 }
1507
1508         /* we should still have the output to wr->data and the input
1509          * from wr->input.  Length should be wr->length.
1510          * wr->data still points in the wb->buf */
1511
1512         if (mac_size != 0)
1513                 {
1514                 if(s->method->ssl3_enc->mac(s,&(p[wr->length + bs]),1) < 0)
1515                         goto err;
1516                 wr->length+=mac_size;
1517                 }
1518
1519         /* this is true regardless of mac size */
1520         wr->input=p;
1521         wr->data=p;
1522
1523
1524         /* ssl3_enc can only have an error on read */
1525         if (bs) /* bs != 0 in case of CBC */
1526                 {
1527                 RAND_pseudo_bytes(p,bs);
1528                 /* master IV and last CBC residue stand for
1529                  * the rest of randomness */
1530                 wr->length += bs;
1531                 }
1532
1533         s->method->ssl3_enc->enc(s,1);
1534
1535         /* record length after mac and block padding */
1536 /*      if (type == SSL3_RT_APPLICATION_DATA ||
1537         (type == SSL3_RT_ALERT && ! SSL_in_init(s))) */
1538
1539         /* there's only one epoch between handshake and app data */
1540
1541         s2n(s->d1->w_epoch, pseq);
1542
1543         /* XDTLS: ?? */
1544 /*      else
1545         s2n(s->d1->handshake_epoch, pseq); */
1546
1547         memcpy(pseq, &(s->s3->write_sequence[2]), 6);
1548         pseq+=6;
1549         s2n(wr->length,pseq);
1550
1551         /* we should now have
1552          * wr->data pointing to the encrypted data, which is
1553          * wr->length long */
1554         wr->type=type; /* not needed but helps for debugging */
1555         wr->length+=DTLS1_RT_HEADER_LENGTH;
1556
1557 #if 0  /* this is now done at the message layer */
1558         /* buffer the record, making it easy to handle retransmits */
1559         if ( type == SSL3_RT_HANDSHAKE || type == SSL3_RT_CHANGE_CIPHER_SPEC)
1560                 dtls1_buffer_record(s, wr->data, wr->length,
1561                         *((PQ_64BIT *)&(s->s3->write_sequence[0])));
1562 #endif
1563
1564         ssl3_record_sequence_update(&(s->s3->write_sequence[0]));
1565
1566         if (create_empty_fragment)
1567                 {
1568                 /* we are in a recursive call;
1569                  * just return the length, don't write out anything here
1570                  */
1571                 return wr->length;
1572                 }
1573
1574         /* now let's set up wb */
1575         wb->left = prefix_len + wr->length;
1576         wb->offset = 0;
1577
1578         /* memorize arguments so that ssl3_write_pending can detect bad write retries later */
1579         s->s3->wpend_tot=len;
1580         s->s3->wpend_buf=buf;
1581         s->s3->wpend_type=type;
1582         s->s3->wpend_ret=len;
1583
1584         /* we now just need to write the buffer */
1585         return ssl3_write_pending(s,type,buf,len);
1586 err:
1587         return -1;
1588         }
1589
1590
1591
1592 static int dtls1_record_replay_check(SSL *s, DTLS1_BITMAP *bitmap)
1593         {
1594         int cmp;
1595         unsigned int shift;
1596         const unsigned char *seq = s->s3->read_sequence;
1597
1598         cmp = satsub64be(seq,bitmap->max_seq_num);
1599         if (cmp > 0)
1600                 {
1601                 memcpy (s->s3->rrec.seq_num,seq,8);
1602                 return 1; /* this record in new */
1603                 }
1604         shift = -cmp;
1605         if (shift >= sizeof(bitmap->map)*8)
1606                 return 0; /* stale, outside the window */
1607         else if (bitmap->map & (1UL<<shift))
1608                 return 0; /* record previously received */
1609
1610         memcpy (s->s3->rrec.seq_num,seq,8);
1611         return 1;
1612         }
1613
1614
1615 static void dtls1_record_bitmap_update(SSL *s, DTLS1_BITMAP *bitmap)
1616         {
1617         int cmp;
1618         unsigned int shift;
1619         const unsigned char *seq = s->s3->read_sequence;
1620
1621         cmp = satsub64be(seq,bitmap->max_seq_num);
1622         if (cmp > 0)
1623                 {
1624                 shift = cmp;
1625                 if (shift < sizeof(bitmap->map)*8)
1626                         bitmap->map <<= shift, bitmap->map |= 1UL;
1627                 else
1628                         bitmap->map = 1UL;
1629                 memcpy(bitmap->max_seq_num,seq,8);
1630                 }
1631         else    {
1632                 shift = -cmp;
1633                 if (shift < sizeof(bitmap->map)*8)
1634                         bitmap->map |= 1UL<<shift;
1635                 }
1636         }
1637
1638
1639 int dtls1_dispatch_alert(SSL *s)
1640         {
1641         int i,j;
1642         void (*cb)(const SSL *ssl,int type,int val)=NULL;
1643         unsigned char buf[DTLS1_AL_HEADER_LENGTH];
1644         unsigned char *ptr = &buf[0];
1645
1646         s->s3->alert_dispatch=0;
1647
1648         memset(buf, 0x00, sizeof(buf));
1649         *ptr++ = s->s3->send_alert[0];
1650         *ptr++ = s->s3->send_alert[1];
1651
1652 #ifdef DTLS1_AD_MISSING_HANDSHAKE_MESSAGE
1653         if (s->s3->send_alert[1] == DTLS1_AD_MISSING_HANDSHAKE_MESSAGE)
1654                 {
1655                 s2n(s->d1->handshake_read_seq, ptr);
1656 #if 0
1657                 if ( s->d1->r_msg_hdr.frag_off == 0)  /* waiting for a new msg */
1658
1659                 else
1660                         s2n(s->d1->r_msg_hdr.seq, ptr); /* partial msg read */
1661 #endif
1662
1663 #if 0
1664                 fprintf(stderr, "s->d1->handshake_read_seq = %d, s->d1->r_msg_hdr.seq = %d\n",s->d1->handshake_read_seq,s->d1->r_msg_hdr.seq);
1665 #endif
1666                 l2n3(s->d1->r_msg_hdr.frag_off, ptr);
1667                 }
1668 #endif
1669
1670         i = do_dtls1_write(s, SSL3_RT_ALERT, &buf[0], sizeof(buf), 0);
1671         if (i <= 0)
1672                 {
1673                 s->s3->alert_dispatch=1;
1674                 /* fprintf( stderr, "not done with alert\n" ); */
1675                 }
1676         else
1677                 {
1678                 if (s->s3->send_alert[0] == SSL3_AL_FATAL
1679 #ifdef DTLS1_AD_MISSING_HANDSHAKE_MESSAGE
1680                     || s->s3->send_alert[1] == DTLS1_AD_MISSING_HANDSHAKE_MESSAGE
1681 #endif
1682                     )
1683                         (void)BIO_flush(s->wbio);
1684
1685                 if (s->msg_callback)
1686                         s->msg_callback(1, s->version, SSL3_RT_ALERT, s->s3->send_alert,
1687                                 2, s, s->msg_callback_arg);
1688
1689                 if (s->info_callback != NULL)
1690                         cb=s->info_callback;
1691                 else if (s->ctx->info_callback != NULL)
1692                         cb=s->ctx->info_callback;
1693
1694                 if (cb != NULL)
1695                         {
1696                         j=(s->s3->send_alert[0]<<8)|s->s3->send_alert[1];
1697                         cb(s,SSL_CB_WRITE_ALERT,j);
1698                         }
1699                 }
1700         return(i);
1701         }
1702
1703
1704 static DTLS1_BITMAP *
1705 dtls1_get_bitmap(SSL *s, SSL3_RECORD *rr, unsigned int *is_next_epoch)
1706     {
1707
1708     *is_next_epoch = 0;
1709
1710     /* In current epoch, accept HM, CCS, DATA, & ALERT */
1711     if (rr->epoch == s->d1->r_epoch)
1712         return &s->d1->bitmap;
1713
1714     /* Only HM and ALERT messages can be from the next epoch */
1715     else if (rr->epoch == (unsigned long)(s->d1->r_epoch + 1) &&
1716         (rr->type == SSL3_RT_HANDSHAKE ||
1717             rr->type == SSL3_RT_ALERT))
1718         {
1719         *is_next_epoch = 1;
1720         return &s->d1->next_bitmap;
1721         }
1722
1723     return NULL;
1724     }
1725
1726 #if 0
1727 static int
1728 dtls1_record_needs_buffering(SSL *s, SSL3_RECORD *rr, unsigned short *priority,
1729         unsigned long *offset)
1730         {
1731
1732         /* alerts are passed up immediately */
1733         if ( rr->type == SSL3_RT_APPLICATION_DATA ||
1734                 rr->type == SSL3_RT_ALERT)
1735                 return 0;
1736
1737         /* Only need to buffer if a handshake is underway.
1738          * (this implies that Hello Request and Client Hello are passed up
1739          * immediately) */
1740         if ( SSL_in_init(s))
1741                 {
1742                 unsigned char *data = rr->data;
1743                 /* need to extract the HM/CCS sequence number here */
1744                 if ( rr->type == SSL3_RT_HANDSHAKE ||
1745                         rr->type == SSL3_RT_CHANGE_CIPHER_SPEC)
1746                         {
1747                         unsigned short seq_num;
1748                         struct hm_header_st msg_hdr;
1749                         struct ccs_header_st ccs_hdr;
1750
1751                         if ( rr->type == SSL3_RT_HANDSHAKE)
1752                                 {
1753                                 dtls1_get_message_header(data, &msg_hdr);
1754                                 seq_num = msg_hdr.seq;
1755                                 *offset = msg_hdr.frag_off;
1756                                 }
1757                         else
1758                                 {
1759                                 dtls1_get_ccs_header(data, &ccs_hdr);
1760                                 seq_num = ccs_hdr.seq;
1761                                 *offset = 0;
1762                                 }
1763
1764                         /* this is either a record we're waiting for, or a
1765                          * retransmit of something we happened to previously
1766                          * receive (higher layers will drop the repeat silently */
1767                         if ( seq_num < s->d1->handshake_read_seq)
1768                                 return 0;
1769                         if (rr->type == SSL3_RT_HANDSHAKE &&
1770                                 seq_num == s->d1->handshake_read_seq &&
1771                                 msg_hdr.frag_off < s->d1->r_msg_hdr.frag_off)
1772                                 return 0;
1773                         else if ( seq_num == s->d1->handshake_read_seq &&
1774                                 (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC ||
1775                                         msg_hdr.frag_off == s->d1->r_msg_hdr.frag_off))
1776                                 return 0;
1777                         else
1778                                 {
1779                                 *priority = seq_num;
1780                                 return 1;
1781                                 }
1782                         }
1783                 else /* unknown record type */
1784                         return 0;
1785                 }
1786
1787         return 0;
1788         }
1789 #endif
1790
1791 void
1792 dtls1_reset_seq_numbers(SSL *s, int rw)
1793         {
1794         unsigned char *seq;
1795         unsigned int seq_bytes = sizeof(s->s3->read_sequence);
1796
1797         if ( rw & SSL3_CC_READ)
1798                 {
1799                 seq = s->s3->read_sequence;
1800                 s->d1->r_epoch++;
1801                 memcpy(&(s->d1->bitmap), &(s->d1->next_bitmap), sizeof(DTLS1_BITMAP));
1802                 memset(&(s->d1->next_bitmap), 0x00, sizeof(DTLS1_BITMAP));
1803                 }
1804         else
1805                 {
1806                 seq = s->s3->write_sequence;
1807                 memcpy(s->d1->last_write_sequence, seq, sizeof(s->s3->write_sequence));
1808                 s->d1->w_epoch++;
1809                 }
1810
1811         memset(seq, 0x00, seq_bytes);
1812         }
1813
1814
1815 static void
1816 dtls1_clear_timeouts(SSL *s)
1817         {
1818         memset(&(s->d1->timeout), 0x00, sizeof(struct dtls1_timeout_st));
1819         }