ssl/s2_pkt.c

   1 /* ssl/s2_pkt.c */
   2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   3  * All rights reserved.
   4  *
   5  * This package is an SSL implementation written
   6  * by Eric Young (eay@cryptsoft.com).
   7  * The implementation was written so as to conform with Netscapes SSL.
   8  *
   9  * This library is free for commercial and non-commercial use as long as
  10  * the following conditions are aheared to.  The following conditions
  11  * apply to all code found in this distribution, be it the RC4, RSA,
  12  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  13  * included with this distribution is covered by the same copyright terms
  14  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  15  *
  16  * Copyright remains Eric Young's, and as such any Copyright notices in
  17  * the code are not to be removed.
  18  * If this package is used in a product, Eric Young should be given attribution
  19  * as the author of the parts of the library used.
  20  * This can be in the form of a textual message at program startup or
  21  * in documentation (online or textual) provided with the package.
  22  *
  23  * Redistribution and use in source and binary forms, with or without
  24  * modification, are permitted provided that the following conditions
  25  * are met:
  26  * 1. Redistributions of source code must retain the copyright
  27  *    notice, this list of conditions and the following disclaimer.
  28  * 2. Redistributions in binary form must reproduce the above copyright
  29  *    notice, this list of conditions and the following disclaimer in the
  30  *    documentation and/or other materials provided with the distribution.
  31  * 3. All advertising materials mentioning features or use of this software
  32  *    must display the following acknowledgement:
  33  *    "This product includes cryptographic software written by
  34  *     Eric Young (eay@cryptsoft.com)"
  35  *    The word 'cryptographic' can be left out if the rouines from the library
  36  *    being used are not cryptographic related :-).
  37  * 4. If you include any Windows specific code (or a derivative thereof) from
  38  *    the apps directory (application code) you must include an acknowledgement:
  39  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  40  *
  41  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  42  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  43  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  44  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  45  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  46  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  47  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  48  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  49  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  50  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  51  * SUCH DAMAGE.
  52  *
  53  * The licence and distribution terms for any publically available version or
  54  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  55  * copied and put under another distribution licence
  56  * [including the GNU Public Licence.]
  57  */
  58 /* ====================================================================
  59  * Copyright (c) 1998-2001 The OpenSSL Project.  All rights reserved.
  60  *
  61  * Redistribution and use in source and binary forms, with or without
  62  * modification, are permitted provided that the following conditions
  63  * are met:
  64  *
  65  * 1. Redistributions of source code must retain the above copyright
  66  *    notice, this list of conditions and the following disclaimer.
  67  *
  68  * 2. Redistributions in binary form must reproduce the above copyright
  69  *    notice, this list of conditions and the following disclaimer in
  70  *    the documentation and/or other materials provided with the
  71  *    distribution.
  72  *
  73  * 3. All advertising materials mentioning features or use of this
  74  *    software must display the following acknowledgment:
  75  *    "This product includes software developed by the OpenSSL Project
  76  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
  77  *
  78  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  79  *    endorse or promote products derived from this software without
  80  *    prior written permission. For written permission, please contact
  81  *    openssl-core@openssl.org.
  82  *
  83  * 5. Products derived from this software may not be called "OpenSSL"
  84  *    nor may "OpenSSL" appear in their names without prior written
  85  *    permission of the OpenSSL Project.
  86  *
  87  * 6. Redistributions of any form whatsoever must retain the following
  88  *    acknowledgment:
  89  *    "This product includes software developed by the OpenSSL Project
  90  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
  91  *
  92  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  93  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  94  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  95  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  96  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  97  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  98  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  99  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 100  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 101  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 102  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 103  * OF THE POSSIBILITY OF SUCH DAMAGE.
 104  * ====================================================================
 105  *
 106  * This product includes cryptographic software written by Eric Young
 107  * (eay@cryptsoft.com).  This product includes software written by Tim
 108  * Hudson (tjh@cryptsoft.com).
 109  *
 110  */
 111
 112 #include "ssl_locl.h"
 113 #ifndef OPENSSL_NO_SSL2
 114 # include <stdio.h>
 115 # include <errno.h>
 116 # define USE_SOCKETS
 117
 118 static int read_n(SSL *s, unsigned int n, unsigned int max,
 119                   unsigned int extend);
 120 static int n_do_ssl_write(SSL *s, const unsigned char *buf, unsigned int len);
 121 static int write_pending(SSL *s, const unsigned char *buf, unsigned int len);
 122 static int ssl_mt_error(int n);
 123
 124 /*
 125  * SSL 2.0 imlementation for SSL_read/SSL_peek - This routine will return 0
 126  * to len bytes, decrypted etc if required.
 127  */
 128 static int ssl2_read_internal(SSL *s, void *buf, int len, int peek)
 129 {
 130     int n;
 131     unsigned char mac[MAX_MAC_SIZE];
 132     unsigned char *p;
 133     int i;
 134     int mac_size;
 135
 136  ssl2_read_again:
 137     if (SSL_in_init(s) && !s->in_handshake) {
 138         n = s->handshake_func(s);
 139         if (n < 0)
 140             return (n);
 141         if (n == 0) {
 142             SSLerr(SSL_F_SSL2_READ_INTERNAL, SSL_R_SSL_HANDSHAKE_FAILURE);
 143             return (-1);
 144         }
 145     }
 146
 147     clear_sys_error();
 148     s->rwstate = SSL_NOTHING;
 149     if (len <= 0)
 150         return (len);
 151
 152     if (s->s2->ract_data_length != 0) { /* read from buffer */
 153         if (len > s->s2->ract_data_length)
 154             n = s->s2->ract_data_length;
 155         else
 156             n = len;
 157
 158         memcpy(buf, s->s2->ract_data, (unsigned int)n);
 159         if (!peek) {
 160             s->s2->ract_data_length -= n;
 161             s->s2->ract_data += n;
 162             if (s->s2->ract_data_length == 0)
 163                 s->rstate = SSL_ST_READ_HEADER;
 164         }
 165
 166         return (n);
 167     }
 168
 169     /*
 170      * s->s2->ract_data_length == 0 Fill the buffer, then goto
 171      * ssl2_read_again.
 172      */
 173
 174     if (s->rstate == SSL_ST_READ_HEADER) {
 175         if (s->first_packet) {
 176             n = read_n(s, 5, SSL2_MAX_RECORD_LENGTH_2_BYTE_HEADER + 2, 0);
 177             if (n <= 0)
 178                 return (n);     /* error or non-blocking */
 179             s->first_packet = 0;
 180             p = s->packet;
 181             if (!((p[0] & 0x80) && ((p[2] == SSL2_MT_CLIENT_HELLO) ||
 182                                     (p[2] == SSL2_MT_SERVER_HELLO)))) {
 183                 SSLerr(SSL_F_SSL2_READ_INTERNAL,
 184                        SSL_R_NON_SSLV2_INITIAL_PACKET);
 185                 return (-1);
 186             }
 187         } else {
 188             n = read_n(s, 2, SSL2_MAX_RECORD_LENGTH_2_BYTE_HEADER + 2, 0);
 189             if (n <= 0)
 190                 return (n);     /* error or non-blocking */
 191         }
 192         /* part read stuff */
 193
 194         s->rstate = SSL_ST_READ_BODY;
 195         p = s->packet;
 196         /* Do header */
 197         /*
 198          * s->s2->padding=0;
 199          */
 200         s->s2->escape = 0;
 201         s->s2->rlength = (((unsigned int)p[0]) << 8) | ((unsigned int)p[1]);
 202         if ((p[0] & TWO_BYTE_BIT)) { /* Two byte header? */
 203             s->s2->three_byte_header = 0;
 204             s->s2->rlength &= TWO_BYTE_MASK;
 205         } else {
 206             s->s2->three_byte_header = 1;
 207             s->s2->rlength &= THREE_BYTE_MASK;
 208
 209             /* security >s2->escape */
 210             s->s2->escape = ((p[0] & SEC_ESC_BIT)) ? 1 : 0;
 211         }
 212     }
 213
 214     if (s->rstate == SSL_ST_READ_BODY) {
 215         n = s->s2->rlength + 2 + s->s2->three_byte_header;
 216         if (n > (int)s->packet_length) {
 217             n -= s->packet_length;
 218             i = read_n(s, (unsigned int)n, (unsigned int)n, 1);
 219             if (i <= 0)
 220                 return (i);     /* ERROR */
 221         }
 222
 223         p = &(s->packet[2]);
 224         s->rstate = SSL_ST_READ_HEADER;
 225         if (s->s2->three_byte_header)
 226             s->s2->padding = *(p++);
 227         else
 228             s->s2->padding = 0;
 229
 230         /* Data portion */
 231         if (s->s2->clear_text) {
 232             mac_size = 0;
 233             s->s2->mac_data = p;
 234             s->s2->ract_data = p;
 235             if (s->s2->padding) {
 236                 SSLerr(SSL_F_SSL2_READ_INTERNAL, SSL_R_ILLEGAL_PADDING);
 237                 return (-1);
 238             }
 239         } else {
 240             mac_size = EVP_MD_CTX_size(s->read_hash);
 241             if (mac_size < 0)
 242                 return -1;
 243             OPENSSL_assert(mac_size <= MAX_MAC_SIZE);
 244             s->s2->mac_data = p;
 245             s->s2->ract_data = &p[mac_size];
 246             if (s->s2->padding + mac_size > s->s2->rlength) {
 247                 SSLerr(SSL_F_SSL2_READ_INTERNAL, SSL_R_ILLEGAL_PADDING);
 248                 return (-1);
 249             }
 250         }
 251
 252         s->s2->ract_data_length = s->s2->rlength;
 253         /*
 254          * added a check for length > max_size in case encryption was not
 255          * turned on yet due to an error
 256          */
 257         if ((!s->s2->clear_text) &&
 258             (s->s2->rlength >= (unsigned int)mac_size)) {
 259             if (!ssl2_enc(s, 0)) {
 260                 SSLerr(SSL_F_SSL2_READ_INTERNAL, SSL_R_DECRYPTION_FAILED);
 261                 return (-1);
 262             }
 263             s->s2->ract_data_length -= mac_size;
 264             ssl2_mac(s, mac, 0);
 265             s->s2->ract_data_length -= s->s2->padding;
 266             if ((CRYPTO_memcmp(mac, s->s2->mac_data, mac_size) != 0) ||
 267                 (s->s2->rlength %
 268                  EVP_CIPHER_CTX_block_size(s->enc_read_ctx) != 0)) {
 269                 SSLerr(SSL_F_SSL2_READ_INTERNAL, SSL_R_BAD_MAC_DECODE);
 270                 return (-1);
 271             }
 272         }
 273         INC32(s->s2->read_sequence); /* expect next number */
 274         /* s->s2->ract_data is now available for processing */
 275
 276         /*
 277          * Possibly the packet that we just read had 0 actual data bytes.
 278          * (SSLeay/OpenSSL itself never sends such packets; see ssl2_write.)
 279          * In this case, returning 0 would be interpreted by the caller as
 280          * indicating EOF, so it's not a good idea.  Instead, we just
 281          * continue reading; thus ssl2_read_internal may have to process
 282          * multiple packets before it can return. [Note that using select()
 283          * for blocking sockets *never* guarantees that the next SSL_read
 284          * will not block -- the available data may contain incomplete
 285          * packets, and except for SSL 2, renegotiation can confuse things
 286          * even more.]
 287          */
 288
 289         goto ssl2_read_again;   /* This should really be "return
 290                                  * ssl2_read(s,buf,len)", but that would
 291                                  * allow for denial-of-service attacks if a C
 292                                  * compiler is used that does not recognize
 293                                  * end-recursion. */
 294     } else {
 295         SSLerr(SSL_F_SSL2_READ_INTERNAL, SSL_R_BAD_STATE);
 296         return (-1);
 297     }
 298 }
 299
 300 int ssl2_read(SSL *s, void *buf, int len)
 301 {
 302     return ssl2_read_internal(s, buf, len, 0);
 303 }
 304
 305 int ssl2_peek(SSL *s, void *buf, int len)
 306 {
 307     return ssl2_read_internal(s, buf, len, 1);
 308 }
 309
 310 /*
 311  * Return values are as per SSL_read()
 312  */
 313 static int read_n(SSL *s, unsigned int n, unsigned int max,
 314                   unsigned int extend)
 315 {
 316     int i, off, newb;
 317
 318     /*
 319      * if there is stuff still in the buffer from a previous read, and there
 320      * is more than we want, take some.
 321      */
 322     if (s->s2->rbuf_left >= (int)n) {
 323         if (extend)
 324             s->packet_length += n;
 325         else {
 326             s->packet = &(s->s2->rbuf[s->s2->rbuf_offs]);
 327             s->packet_length = n;
 328         }
 329         s->s2->rbuf_left -= n;
 330         s->s2->rbuf_offs += n;
 331         return (n);
 332     }
 333
 334     if (!s->read_ahead)
 335         max = n;
 336     if (max > (unsigned int)(SSL2_MAX_RECORD_LENGTH_2_BYTE_HEADER + 2))
 337         max = SSL2_MAX_RECORD_LENGTH_2_BYTE_HEADER + 2;
 338
 339     /*
 340      * Else we want more than we have. First, if there is some left or we
 341      * want to extend
 342      */
 343     off = 0;
 344     if ((s->s2->rbuf_left != 0) || ((s->packet_length != 0) && extend)) {
 345         newb = s->s2->rbuf_left;
 346         if (extend) {
 347             off = s->packet_length;
 348             if (s->packet != s->s2->rbuf)
 349                 memcpy(s->s2->rbuf, s->packet, (unsigned int)newb + off);
 350         } else if (s->s2->rbuf_offs != 0) {
 351             memcpy(s->s2->rbuf, &(s->s2->rbuf[s->s2->rbuf_offs]),
 352                    (unsigned int)newb);
 353             s->s2->rbuf_offs = 0;
 354         }
 355         s->s2->rbuf_left = 0;
 356     } else
 357         newb = 0;
 358
 359     /*
 360      * off is the offset to start writing too. r->s2->rbuf_offs is the
 361      * 'unread data', now 0. newb is the number of new bytes so far
 362      */
 363     s->packet = s->s2->rbuf;
 364     while (newb < (int)n) {
 365         clear_sys_error();
 366         if (s->rbio != NULL) {
 367             s->rwstate = SSL_READING;
 368             i = BIO_read(s->rbio, (char *)&(s->s2->rbuf[off + newb]),
 369                          max - newb);
 370         } else {
 371             SSLerr(SSL_F_READ_N, SSL_R_READ_BIO_NOT_SET);
 372             i = -1;
 373         }
 374 # ifdef PKT_DEBUG
 375         if (s->debug & 0x01)
 376             sleep(1);
 377 # endif
 378         if (i <= 0) {
 379             s->s2->rbuf_left += newb;
 380             return i;
 381         }
 382         newb += i;
 383     }
 384
 385     /* record unread data */
 386     if (newb > (int)n) {
 387         s->s2->rbuf_offs = n + off;
 388         s->s2->rbuf_left = newb - n;
 389     } else {
 390         s->s2->rbuf_offs = 0;
 391         s->s2->rbuf_left = 0;
 392     }
 393     if (extend)
 394         s->packet_length += n;
 395     else
 396         s->packet_length = n;
 397     s->rwstate = SSL_NOTHING;
 398     return (n);
 399 }
 400
 401 int ssl2_write(SSL *s, const void *_buf, int len)
 402 {
 403     const unsigned char *buf = _buf;
 404     unsigned int n, tot;
 405     int i;
 406
 407     if (SSL_in_init(s) && !s->in_handshake) {
 408         i = s->handshake_func(s);
 409         if (i < 0)
 410             return (i);
 411         if (i == 0) {
 412             SSLerr(SSL_F_SSL2_WRITE, SSL_R_SSL_HANDSHAKE_FAILURE);
 413             return (-1);
 414         }
 415     }
 416
 417     if (s->error) {
 418         ssl2_write_error(s);
 419         if (s->error)
 420             return (-1);
 421     }
 422
 423     clear_sys_error();
 424     s->rwstate = SSL_NOTHING;
 425     if (len <= 0)
 426         return (len);
 427
 428     tot = s->s2->wnum;
 429     s->s2->wnum = 0;
 430
 431     n = (len - tot);
 432     for (;;) {
 433         i = n_do_ssl_write(s, &(buf[tot]), n);
 434         if (i <= 0) {
 435             s->s2->wnum = tot;
 436             return (i);
 437         }
 438         if ((i == (int)n) || (s->mode & SSL_MODE_ENABLE_PARTIAL_WRITE)) {
 439             return (tot + i);
 440         }
 441
 442         n -= i;
 443         tot += i;
 444     }
 445 }
 446
 447 /*
 448  * Return values are as per SSL_write()
 449  */
 450 static int write_pending(SSL *s, const unsigned char *buf, unsigned int len)
 451 {
 452     int i;
 453
 454     /* s->s2->wpend_len != 0 MUST be true. */
 455
 456     /*
 457      * check that they have given us the same buffer to write
 458      */
 459     if ((s->s2->wpend_tot > (int)len) ||
 460         ((s->s2->wpend_buf != buf) &&
 461          !(s->mode & SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER))) {
 462         SSLerr(SSL_F_WRITE_PENDING, SSL_R_BAD_WRITE_RETRY);
 463         return (-1);
 464     }
 465
 466     for (;;) {
 467         clear_sys_error();
 468         if (s->wbio != NULL) {
 469             s->rwstate = SSL_WRITING;
 470             i = BIO_write(s->wbio,
 471                           (char *)&(s->s2->write_ptr[s->s2->wpend_off]),
 472                           (unsigned int)s->s2->wpend_len);
 473         } else {
 474             SSLerr(SSL_F_WRITE_PENDING, SSL_R_WRITE_BIO_NOT_SET);
 475             i = -1;
 476         }
 477 # ifdef PKT_DEBUG
 478         if (s->debug & 0x01)
 479             sleep(1);
 480 # endif
 481         if (i == s->s2->wpend_len) {
 482             s->s2->wpend_len = 0;
 483             s->rwstate = SSL_NOTHING;
 484             return (s->s2->wpend_ret);
 485         } else if (i <= 0)
 486             return i;
 487         s->s2->wpend_off += i;
 488         s->s2->wpend_len -= i;
 489     }
 490 }
 491
 492 static int n_do_ssl_write(SSL *s, const unsigned char *buf, unsigned int len)
 493 {
 494     unsigned int j, k, olen, p, bs;
 495     int mac_size;
 496     register unsigned char *pp;
 497
 498     olen = len;
 499
 500     /*
 501      * first check if there is data from an encryption waiting to be sent -
 502      * it must be sent because the other end is waiting. This will happen
 503      * with non-blocking IO.  We print it and then return.
 504      */
 505     if (s->s2->wpend_len != 0)
 506         return (write_pending(s, buf, len));
 507
 508     /* set mac_size to mac size */
 509     if (s->s2->clear_text)
 510         mac_size = 0;
 511     else {
 512         mac_size = EVP_MD_CTX_size(s->write_hash);
 513         if (mac_size < 0)
 514             return -1;
 515     }
 516
 517     /* lets set the pad p */
 518     if (s->s2->clear_text) {
 519         if (len > SSL2_MAX_RECORD_LENGTH_2_BYTE_HEADER)
 520             len = SSL2_MAX_RECORD_LENGTH_2_BYTE_HEADER;
 521         p = 0;
 522         s->s2->three_byte_header = 0;
 523         /* len=len; */
 524     } else {
 525         bs = EVP_CIPHER_CTX_block_size(s->enc_read_ctx);
 526         j = len + mac_size;
 527         /*
 528          * Two-byte headers allow for a larger record length than three-byte
 529          * headers, but we can't use them if we need padding or if we have to
 530          * set the escape bit.
 531          */
 532         if ((j > SSL2_MAX_RECORD_LENGTH_3_BYTE_HEADER) && (!s->s2->escape)) {
 533             if (j > SSL2_MAX_RECORD_LENGTH_2_BYTE_HEADER)
 534                 j = SSL2_MAX_RECORD_LENGTH_2_BYTE_HEADER;
 535             /*
 536              * set k to the max number of bytes with 2 byte header
 537              */
 538             k = j - (j % bs);
 539             /* how many data bytes? */
 540             len = k - mac_size;
 541             s->s2->three_byte_header = 0;
 542             p = 0;
 543         } else if ((bs <= 1) && (!s->s2->escape)) {
 544             /*-
 545              * j <= SSL2_MAX_RECORD_LENGTH_3_BYTE_HEADER, thus
 546              * j < SSL2_MAX_RECORD_LENGTH_2_BYTE_HEADER
 547              */
 548             s->s2->three_byte_header = 0;
 549             p = 0;
 550         } else {                /* we may have to use a 3 byte header */
 551
 552             /*-
 553              * If s->s2->escape is not set, then
 554              * j <= SSL2_MAX_RECORD_LENGTH_3_BYTE_HEADER, and thus
 555              * j < SSL2_MAX_RECORD_LENGTH_2_BYTE_HEADER.
 556              */
 557             p = (j % bs);
 558             p = (p == 0) ? 0 : (bs - p);
 559             if (s->s2->escape) {
 560                 s->s2->three_byte_header = 1;
 561                 if (j > SSL2_MAX_RECORD_LENGTH_3_BYTE_HEADER)
 562                     j = SSL2_MAX_RECORD_LENGTH_3_BYTE_HEADER;
 563             } else
 564                 s->s2->three_byte_header = (p == 0) ? 0 : 1;
 565         }
 566     }
 567
 568     /*-
 569      * Now
 570      *      j <= SSL2_MAX_RECORD_LENGTH_2_BYTE_HEADER
 571      * holds, and if s->s2->three_byte_header is set, then even
 572      *      j <= SSL2_MAX_RECORD_LENGTH_3_BYTE_HEADER.
 573      */
 574
 575     /*
 576      * mac_size is the number of MAC bytes len is the number of data bytes we
 577      * are going to send p is the number of padding bytes (if it is a
 578      * two-byte header, then p == 0)
 579      */
 580
 581     s->s2->wlength = len;
 582     s->s2->padding = p;
 583     s->s2->mac_data = &(s->s2->wbuf[3]);
 584     s->s2->wact_data = &(s->s2->wbuf[3 + mac_size]);
 585
 586     /*
 587      * It would be clearer to write this as follows:
 588      *     if (mac_size + len + p > SSL2_MAX_RECORD_LENGTH_2_BYTE_HEADER)
 589      * However |len| is user input that could in theory be very large. We
 590      * know |mac_size| and |p| are small, so to avoid any possibility of
 591      * overflow we write it like this.
 592      *
 593      * In theory this should never fail because the logic above should have
 594      * modified |len| if it is too big. But we are being cautious.
 595      */
 596     if (len > (SSL2_MAX_RECORD_LENGTH_2_BYTE_HEADER - (mac_size + p))) {
 597         return -1;
 598     }
 599     /* we copy the data into s->s2->wbuf */
 600     memcpy(s->s2->wact_data, buf, len);
 601     if (p)
 602         memset(&(s->s2->wact_data[len]), 0, p); /* arbitrary padding */
 603
 604     if (!s->s2->clear_text) {
 605         s->s2->wact_data_length = len + p;
 606         ssl2_mac(s, s->s2->mac_data, 1);
 607         s->s2->wlength += p + mac_size;
 608         if (ssl2_enc(s, 1) < 1)
 609             return -1;
 610     }
 611
 612     /* package up the header */
 613     s->s2->wpend_len = s->s2->wlength;
 614     if (s->s2->three_byte_header) { /* 3 byte header */
 615         pp = s->s2->mac_data;
 616         pp -= 3;
 617         pp[0] = (s->s2->wlength >> 8) & (THREE_BYTE_MASK >> 8);
 618         if (s->s2->escape)
 619             pp[0] |= SEC_ESC_BIT;
 620         pp[1] = s->s2->wlength & 0xff;
 621         pp[2] = s->s2->padding;
 622         s->s2->wpend_len += 3;
 623     } else {
 624         pp = s->s2->mac_data;
 625         pp -= 2;
 626         pp[0] = ((s->s2->wlength >> 8) & (TWO_BYTE_MASK >> 8)) | TWO_BYTE_BIT;
 627         pp[1] = s->s2->wlength & 0xff;
 628         s->s2->wpend_len += 2;
 629     }
 630     s->s2->write_ptr = pp;
 631
 632     INC32(s->s2->write_sequence); /* expect next number */
 633
 634     /* lets try to actually write the data */
 635     s->s2->wpend_tot = olen;
 636     s->s2->wpend_buf = buf;
 637
 638     s->s2->wpend_ret = len;
 639
 640     s->s2->wpend_off = 0;
 641     return (write_pending(s, buf, olen));
 642 }
 643
 644 int ssl2_part_read(SSL *s, unsigned long f, int i)
 645 {
 646     unsigned char *p;
 647     int j;
 648
 649     if (i < 0) {
 650         /* ssl2_return_error(s); */
 651         /*
 652          * for non-blocking io, this is not necessarily fatal
 653          */
 654         return (i);
 655     } else {
 656         s->init_num += i;
 657
 658         /*
 659          * Check for error.  While there are recoverable errors, this
 660          * function is not called when those must be expected; any error
 661          * detected here is fatal.
 662          */
 663         if (s->init_num >= 3) {
 664             p = (unsigned char *)s->init_buf->data;
 665             if (p[0] == SSL2_MT_ERROR) {
 666                 j = (p[1] << 8) | p[2];
 667                 SSLerr((int)f, ssl_mt_error(j));
 668                 s->init_num -= 3;
 669                 if (s->init_num > 0)
 670                     memmove(p, p + 3, s->init_num);
 671             }
 672         }
 673
 674         /*
 675          * If it's not an error message, we have some error anyway -- the
 676          * message was shorter than expected.  This too is treated as fatal
 677          * (at least if SSL_get_error is asked for its opinion).
 678          */
 679         return (0);
 680     }
 681 }
 682
 683 int ssl2_do_write(SSL *s)
 684 {
 685     int ret;
 686
 687     ret = ssl2_write(s, &s->init_buf->data[s->init_off], s->init_num);
 688     if (ret == s->init_num) {
 689         if (s->msg_callback)
 690             s->msg_callback(1, s->version, 0, s->init_buf->data,
 691                             (size_t)(s->init_off + s->init_num), s,
 692                             s->msg_callback_arg);
 693         return (1);
 694     }
 695     if (ret < 0)
 696         return (-1);
 697     s->init_off += ret;
 698     s->init_num -= ret;
 699     return (0);
 700 }
 701
 702 static int ssl_mt_error(int n)
 703 {
 704     int ret;
 705
 706     switch (n) {
 707     case SSL2_PE_NO_CIPHER:
 708         ret = SSL_R_PEER_ERROR_NO_CIPHER;
 709         break;
 710     case SSL2_PE_NO_CERTIFICATE:
 711         ret = SSL_R_PEER_ERROR_NO_CERTIFICATE;
 712         break;
 713     case SSL2_PE_BAD_CERTIFICATE:
 714         ret = SSL_R_PEER_ERROR_CERTIFICATE;
 715         break;
 716     case SSL2_PE_UNSUPPORTED_CERTIFICATE_TYPE:
 717         ret = SSL_R_PEER_ERROR_UNSUPPORTED_CERTIFICATE_TYPE;
 718         break;
 719     default:
 720         ret = SSL_R_UNKNOWN_REMOTE_ERROR_TYPE;
 721         break;
 722     }
 723     return (ret);
 724 }
 725 #else                           /* !OPENSSL_NO_SSL2 */
 726
 727 # if PEDANTIC
 728 static void *dummy = &dummy;
 729 # endif
 730
 731 #endif