lib/libcrypto/bio/bss_bio.c

   1 /* $OpenBSD: bss_bio.c,v 1.23 2017/01/29 17:49:22 beck Exp $ */
   2 /* ====================================================================
   3  * Copyright (c) 1998-2003 The OpenSSL Project.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  *
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in
  14  *    the documentation and/or other materials provided with the
  15  *    distribution.
  16  *
  17  * 3. All advertising materials mentioning features or use of this
  18  *    software must display the following acknowledgment:
  19  *    "This product includes software developed by the OpenSSL Project
  20  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
  21  *
  22  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
  23  *    endorse or promote products derived from this software without
  24  *    prior written permission. For written permission, please contact
  25  *    openssl-core@openssl.org.
  26  *
  27  * 5. Products derived from this software may not be called "OpenSSL"
  28  *    nor may "OpenSSL" appear in their names without prior written
  29  *    permission of the OpenSSL Project.
  30  *
  31  * 6. Redistributions of any form whatsoever must retain the following
  32  *    acknowledgment:
  33  *    "This product includes software developed by the OpenSSL Project
  34  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
  35  *
  36  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
  37  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  38  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  39  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
  40  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  41  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  42  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  43  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  44  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  45  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  46  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  47  * OF THE POSSIBILITY OF SUCH DAMAGE.
  48  * ====================================================================
  49  *
  50  * This product includes cryptographic software written by Eric Young
  51  * (eay@cryptsoft.com).  This product includes software written by Tim
  52  * Hudson (tjh@cryptsoft.com).
  53  *
  54  */
  55
  56 /* Special method for a BIO where the other endpoint is also a BIO
  57  * of this kind, handled by the same thread (i.e. the "peer" is actually
  58  * ourselves, wearing a different hat).
  59  * Such "BIO pairs" are mainly for using the SSL library with I/O interfaces
  60  * for which no specific BIO method is available.
  61  * See ssl/ssltest.c for some hints on how this can be used. */
  62
  63 /* BIO_DEBUG implies BIO_PAIR_DEBUG */
  64 #ifdef BIO_DEBUG
  65 # ifndef BIO_PAIR_DEBUG
  66 #  define BIO_PAIR_DEBUG
  67 # endif
  68 #endif
  69
  70 /* disable assert() unless BIO_PAIR_DEBUG has been defined */
  71 #ifndef BIO_PAIR_DEBUG
  72 # ifndef NDEBUG
  73 #  define NDEBUG
  74 # endif
  75 #endif
  76
  77 #include <assert.h>
  78 #include <limits.h>
  79 #include <stdlib.h>
  80 #include <string.h>
  81 #include <sys/types.h>
  82
  83 #include <openssl/bio.h>
  84 #include <openssl/err.h>
  85 #include <openssl/crypto.h>
  86
  87 static int bio_new(BIO *bio);
  88 static int bio_free(BIO *bio);
  89 static int bio_read(BIO *bio, char *buf, int size);
  90 static int bio_write(BIO *bio, const char *buf, int num);
  91 static long bio_ctrl(BIO *bio, int cmd, long num, void *ptr);
  92 static int bio_puts(BIO *bio, const char *str);
  93
  94 static int bio_make_pair(BIO *bio1, BIO *bio2);
  95 static void bio_destroy_pair(BIO *bio);
  96
  97 static BIO_METHOD methods_biop = {
  98         .type = BIO_TYPE_BIO,
  99         .name = "BIO pair",
 100         .bwrite = bio_write,
 101         .bread = bio_read,
 102         .bputs = bio_puts,
 103         .ctrl = bio_ctrl,
 104         .create = bio_new,
 105         .destroy = bio_free
 106 };
 107
 108 BIO_METHOD *
 109 BIO_s_bio(void)
 110 {
 111         return &methods_biop;
 112 }
 113
 114 struct bio_bio_st {
 115         BIO *peer;      /* NULL if buf == NULL.
 116                          * If peer != NULL, then peer->ptr is also a bio_bio_st,
 117                          * and its "peer" member points back to us.
 118                          * peer != NULL iff init != 0 in the BIO. */
 119
 120         /* This is for what we write (i.e. reading uses peer's struct): */
 121         int closed;     /* valid iff peer != NULL */
 122         size_t len;     /* valid iff buf != NULL; 0 if peer == NULL */
 123         size_t offset;  /* valid iff buf != NULL; 0 if len == 0 */
 124         size_t size;
 125         char *buf;      /* "size" elements (if != NULL) */
 126
 127         size_t request; /* valid iff peer != NULL; 0 if len != 0,
 128                          * otherwise set by peer to number of bytes
 129                          * it (unsuccessfully) tried to read,
 130                          * never more than buffer space (size-len) warrants. */
 131 };
 132
 133 static int
 134 bio_new(BIO *bio)
 135 {
 136         struct bio_bio_st *b;
 137
 138         b = malloc(sizeof *b);
 139         if (b == NULL)
 140                 return 0;
 141
 142         b->peer = NULL;
 143         b->size = 17 * 1024; /* enough for one TLS record (just a default) */
 144         b->buf = NULL;
 145
 146         bio->ptr = b;
 147         return 1;
 148 }
 149
 150 static int
 151 bio_free(BIO *bio)
 152 {
 153         struct bio_bio_st *b;
 154
 155         if (bio == NULL)
 156                 return 0;
 157         b = bio->ptr;
 158
 159         assert(b != NULL);
 160
 161         if (b->peer)
 162                 bio_destroy_pair(bio);
 163
 164         free(b->buf);
 165         free(b);
 166         return 1;
 167 }
 168
 169
 170
 171 static int
 172 bio_read(BIO *bio, char *buf, int size_)
 173 {
 174         size_t size = size_;
 175         size_t rest;
 176         struct bio_bio_st *b, *peer_b;
 177
 178         BIO_clear_retry_flags(bio);
 179
 180         if (!bio->init)
 181                 return 0;
 182
 183         b = bio->ptr;
 184         assert(b != NULL);
 185         assert(b->peer != NULL);
 186         peer_b = b->peer->ptr;
 187         assert(peer_b != NULL);
 188         assert(peer_b->buf != NULL);
 189
 190         peer_b->request = 0; /* will be set in "retry_read" situation */
 191
 192         if (buf == NULL || size == 0)
 193                 return 0;
 194
 195         if (peer_b->len == 0) {
 196                 if (peer_b->closed)
 197                         return 0; /* writer has closed, and no data is left */
 198                 else {
 199                         BIO_set_retry_read(bio); /* buffer is empty */
 200                         if (size <= peer_b->size)
 201                                 peer_b->request = size;
 202                         else
 203                                 /* don't ask for more than the peer can
 204                                  * deliver in one write */
 205                                 peer_b->request = peer_b->size;
 206                         return -1;
 207                 }
 208         }
 209
 210         /* we can read */
 211         if (peer_b->len < size)
 212                 size = peer_b->len;
 213
 214         /* now read "size" bytes */
 215
 216         rest = size;
 217
 218         assert(rest > 0);
 219         do /* one or two iterations */
 220         {
 221                 size_t chunk;
 222
 223                 assert(rest <= peer_b->len);
 224                 if (peer_b->offset + rest <= peer_b->size)
 225                         chunk = rest;
 226                 else
 227                         /* wrap around ring buffer */
 228                         chunk = peer_b->size - peer_b->offset;
 229                 assert(peer_b->offset + chunk <= peer_b->size);
 230
 231                 memcpy(buf, peer_b->buf + peer_b->offset, chunk);
 232
 233                 peer_b->len -= chunk;
 234                 if (peer_b->len) {
 235                         peer_b->offset += chunk;
 236                         assert(peer_b->offset <= peer_b->size);
 237                         if (peer_b->offset == peer_b->size)
 238                                 peer_b->offset = 0;
 239                         buf += chunk;
 240                 } else {
 241                         /* buffer now empty, no need to advance "buf" */
 242                         assert(chunk == rest);
 243                         peer_b->offset = 0;
 244                 }
 245                 rest -= chunk;
 246         } while (rest);
 247
 248         return size;
 249 }
 250
 251 /* non-copying interface: provide pointer to available data in buffer
 252  *    bio_nread0:  return number of available bytes
 253  *    bio_nread:   also advance index
 254  * (example usage:  bio_nread0(), read from buffer, bio_nread()
 255  *  or just         bio_nread(), read from buffer)
 256  */
 257 /* WARNING: The non-copying interface is largely untested as of yet
 258  * and may contain bugs. */
 259 static ssize_t
 260 bio_nread0(BIO *bio, char **buf)
 261 {
 262         struct bio_bio_st *b, *peer_b;
 263         ssize_t num;
 264
 265         BIO_clear_retry_flags(bio);
 266
 267         if (!bio->init)
 268                 return 0;
 269
 270         b = bio->ptr;
 271         assert(b != NULL);
 272         assert(b->peer != NULL);
 273         peer_b = b->peer->ptr;
 274         assert(peer_b != NULL);
 275         assert(peer_b->buf != NULL);
 276
 277         peer_b->request = 0;
 278
 279         if (peer_b->len == 0) {
 280                 char dummy;
 281
 282                 /* avoid code duplication -- nothing available for reading */
 283                 return bio_read(bio, &dummy, 1); /* returns 0 or -1 */
 284         }
 285
 286         num = peer_b->len;
 287         if (peer_b->size < peer_b->offset + num)
 288                 /* no ring buffer wrap-around for non-copying interface */
 289                 num = peer_b->size - peer_b->offset;
 290         assert(num > 0);
 291
 292         if (buf != NULL)
 293                 *buf = peer_b->buf + peer_b->offset;
 294         return num;
 295 }
 296
 297 static ssize_t
 298 bio_nread(BIO *bio, char **buf, size_t num_)
 299 {
 300         struct bio_bio_st *b, *peer_b;
 301         ssize_t num, available;
 302
 303         if (num_ > SSIZE_MAX)
 304                 num = SSIZE_MAX;
 305         else
 306                 num = (ssize_t)num_;
 307
 308         available = bio_nread0(bio, buf);
 309         if (num > available)
 310                 num = available;
 311         if (num <= 0)
 312                 return num;
 313
 314         b = bio->ptr;
 315         peer_b = b->peer->ptr;
 316
 317         peer_b->len -= num;
 318         if (peer_b->len) {
 319                 peer_b->offset += num;
 320                 assert(peer_b->offset <= peer_b->size);
 321                 if (peer_b->offset == peer_b->size)
 322                         peer_b->offset = 0;
 323         } else
 324                 peer_b->offset = 0;
 325
 326         return num;
 327 }
 328
 329
 330 static int
 331 bio_write(BIO *bio, const char *buf, int num_)
 332 {
 333         size_t num = num_;
 334         size_t rest;
 335         struct bio_bio_st *b;
 336
 337         BIO_clear_retry_flags(bio);
 338
 339         if (!bio->init || buf == NULL || num == 0)
 340                 return 0;
 341
 342         b = bio->ptr;
 343
 344         assert(b != NULL);
 345         assert(b->peer != NULL);
 346         assert(b->buf != NULL);
 347
 348         b->request = 0;
 349         if (b->closed) {
 350                 /* we already closed */
 351                 BIOerror(BIO_R_BROKEN_PIPE);
 352                 return -1;
 353         }
 354
 355         assert(b->len <= b->size);
 356
 357         if (b->len == b->size) {
 358                 BIO_set_retry_write(bio); /* buffer is full */
 359                 return -1;
 360         }
 361
 362         /* we can write */
 363         if (num > b->size - b->len)
 364                 num = b->size - b->len;
 365
 366         /* now write "num" bytes */
 367
 368         rest = num;
 369
 370         assert(rest > 0);
 371         do /* one or two iterations */
 372         {
 373                 size_t write_offset;
 374                 size_t chunk;
 375
 376                 assert(b->len + rest <= b->size);
 377
 378                 write_offset = b->offset + b->len;
 379                 if (write_offset >= b->size)
 380                         write_offset -= b->size;
 381                 /* b->buf[write_offset] is the first byte we can write to. */
 382
 383                 if (write_offset + rest <= b->size)
 384                         chunk = rest;
 385                 else
 386                         /* wrap around ring buffer */
 387                         chunk = b->size - write_offset;
 388
 389                 memcpy(b->buf + write_offset, buf, chunk);
 390
 391                 b->len += chunk;
 392
 393                 assert(b->len <= b->size);
 394
 395                 rest -= chunk;
 396                 buf += chunk;
 397         } while (rest);
 398
 399         return num;
 400 }
 401
 402 /* non-copying interface: provide pointer to region to write to
 403  *   bio_nwrite0:  check how much space is available
 404  *   bio_nwrite:   also increase length
 405  * (example usage:  bio_nwrite0(), write to buffer, bio_nwrite()
 406  *  or just         bio_nwrite(), write to buffer)
 407  */
 408 static ssize_t
 409 bio_nwrite0(BIO *bio, char **buf)
 410 {
 411         struct bio_bio_st *b;
 412         size_t num;
 413         size_t write_offset;
 414
 415         BIO_clear_retry_flags(bio);
 416
 417         if (!bio->init)
 418                 return 0;
 419
 420         b = bio->ptr;
 421
 422         assert(b != NULL);
 423         assert(b->peer != NULL);
 424         assert(b->buf != NULL);
 425
 426         b->request = 0;
 427         if (b->closed) {
 428                 BIOerror(BIO_R_BROKEN_PIPE);
 429                 return -1;
 430         }
 431
 432         assert(b->len <= b->size);
 433
 434         if (b->len == b->size) {
 435                 BIO_set_retry_write(bio);
 436                 return -1;
 437         }
 438
 439         num = b->size - b->len;
 440         write_offset = b->offset + b->len;
 441         if (write_offset >= b->size)
 442                 write_offset -= b->size;
 443         if (write_offset + num > b->size)
 444                 /* no ring buffer wrap-around for non-copying interface
 445                  * (to fulfil the promise by BIO_ctrl_get_write_guarantee,
 446                  * BIO_nwrite may have to be called twice) */
 447                 num = b->size - write_offset;
 448
 449         if (buf != NULL)
 450                 *buf = b->buf + write_offset;
 451         assert(write_offset + num <= b->size);
 452
 453         return num;
 454 }
 455
 456 static ssize_t
 457 bio_nwrite(BIO *bio, char **buf, size_t num_)
 458 {
 459         struct bio_bio_st *b;
 460         ssize_t num, space;
 461
 462         if (num_ > SSIZE_MAX)
 463                 num = SSIZE_MAX;
 464         else
 465                 num = (ssize_t)num_;
 466
 467         space = bio_nwrite0(bio, buf);
 468         if (num > space)
 469                 num = space;
 470         if (num <= 0)
 471                 return num;
 472         b = bio->ptr;
 473         assert(b != NULL);
 474         b->len += num;
 475         assert(b->len <= b->size);
 476
 477         return num;
 478 }
 479
 480
 481 static long
 482 bio_ctrl(BIO *bio, int cmd, long num, void *ptr)
 483 {
 484         long ret;
 485         struct bio_bio_st *b = bio->ptr;
 486
 487         assert(b != NULL);
 488
 489         switch (cmd) {
 490                 /* specific CTRL codes */
 491
 492         case BIO_C_SET_WRITE_BUF_SIZE:
 493                 if (b->peer) {
 494                         BIOerror(BIO_R_IN_USE);
 495                         ret = 0;
 496                 } else if (num == 0) {
 497                         BIOerror(BIO_R_INVALID_ARGUMENT);
 498                         ret = 0;
 499                 } else {
 500                         size_t new_size = num;
 501
 502                         if (b->size != new_size) {
 503                                 free(b->buf);
 504                                 b->buf = NULL;
 505                                 b->size = new_size;
 506                         }
 507                         ret = 1;
 508                 }
 509                 break;
 510
 511         case BIO_C_GET_WRITE_BUF_SIZE:
 512                 ret = (long) b->size;
 513                 break;
 514
 515         case BIO_C_MAKE_BIO_PAIR:
 516                 {
 517                         BIO *other_bio = ptr;
 518
 519                         if (bio_make_pair(bio, other_bio))
 520                                 ret = 1;
 521                         else
 522                                 ret = 0;
 523                 }
 524                 break;
 525
 526         case BIO_C_DESTROY_BIO_PAIR:
 527                 /* Affects both BIOs in the pair -- call just once!
 528                  * Or let BIO_free(bio1); BIO_free(bio2); do the job. */
 529                 bio_destroy_pair(bio);
 530                 ret = 1;
 531                 break;
 532
 533         case BIO_C_GET_WRITE_GUARANTEE:
 534                 /* How many bytes can the caller feed to the next write
 535                  * without having to keep any? */
 536                 if (b->peer == NULL || b->closed)
 537                         ret = 0;
 538                 else
 539                         ret = (long) b->size - b->len;
 540                 break;
 541
 542         case BIO_C_GET_READ_REQUEST:
 543                 /* If the peer unsuccessfully tried to read, how many bytes
 544                  * were requested?  (As with BIO_CTRL_PENDING, that number
 545                  * can usually be treated as boolean.) */
 546                 ret = (long) b->request;
 547                 break;
 548
 549         case BIO_C_RESET_READ_REQUEST:
 550                 /* Reset request.  (Can be useful after read attempts
 551                  * at the other side that are meant to be non-blocking,
 552                  * e.g. when probing SSL_read to see if any data is
 553                  * available.) */
 554                 b->request = 0;
 555                 ret = 1;
 556                 break;
 557
 558         case BIO_C_SHUTDOWN_WR:
 559                 /* similar to shutdown(..., SHUT_WR) */
 560                 b->closed = 1;
 561                 ret = 1;
 562                 break;
 563
 564         case BIO_C_NREAD0:
 565                 /* prepare for non-copying read */
 566                 ret = (long) bio_nread0(bio, ptr);
 567                 break;
 568
 569         case BIO_C_NREAD:
 570                 /* non-copying read */
 571                 ret = (long) bio_nread(bio, ptr, (size_t) num);
 572                 break;
 573
 574         case BIO_C_NWRITE0:
 575                 /* prepare for non-copying write */
 576                 ret = (long) bio_nwrite0(bio, ptr);
 577                 break;
 578
 579         case BIO_C_NWRITE:
 580                 /* non-copying write */
 581                 ret = (long) bio_nwrite(bio, ptr, (size_t) num);
 582                 break;
 583
 584
 585                 /* standard CTRL codes follow */
 586
 587         case BIO_CTRL_RESET:
 588                 if (b->buf != NULL) {
 589                         b->len = 0;
 590                         b->offset = 0;
 591                 }
 592                 ret = 0;
 593                 break;
 594
 595
 596         case BIO_CTRL_GET_CLOSE:
 597                 ret = bio->shutdown;
 598                 break;
 599
 600         case BIO_CTRL_SET_CLOSE:
 601                 bio->shutdown = (int) num;
 602                 ret = 1;
 603                 break;
 604
 605         case BIO_CTRL_PENDING:
 606                 if (b->peer != NULL) {
 607                         struct bio_bio_st *peer_b = b->peer->ptr;
 608
 609                         ret = (long) peer_b->len;
 610                 } else
 611                         ret = 0;
 612                 break;
 613
 614         case BIO_CTRL_WPENDING:
 615                 if (b->buf != NULL)
 616                         ret = (long) b->len;
 617                 else
 618                         ret = 0;
 619                 break;
 620
 621         case BIO_CTRL_DUP:
 622                 /* See BIO_dup_chain for circumstances we have to expect. */
 623                 {
 624                         BIO *other_bio = ptr;
 625                         struct bio_bio_st *other_b;
 626
 627                         assert(other_bio != NULL);
 628                         other_b = other_bio->ptr;
 629                         assert(other_b != NULL);
 630
 631                         assert(other_b->buf == NULL); /* other_bio is always fresh */
 632
 633                         other_b->size = b->size;
 634                 }
 635
 636                 ret = 1;
 637                 break;
 638
 639         case BIO_CTRL_FLUSH:
 640                 ret = 1;
 641                 break;
 642
 643         case BIO_CTRL_EOF:
 644                 {
 645                         BIO *other_bio = ptr;
 646
 647                         if (other_bio) {
 648                                 struct bio_bio_st *other_b = other_bio->ptr;
 649
 650                                 assert(other_b != NULL);
 651                                 ret = other_b->len == 0 && other_b->closed;
 652                         } else
 653                                 ret = 1;
 654                 }
 655                 break;
 656
 657         default:
 658                 ret = 0;
 659         }
 660         return ret;
 661 }
 662
 663 static int
 664 bio_puts(BIO *bio, const char *str)
 665 {
 666         return bio_write(bio, str, strlen(str));
 667 }
 668
 669
 670 static int
 671 bio_make_pair(BIO *bio1, BIO *bio2)
 672 {
 673         struct bio_bio_st *b1, *b2;
 674
 675         assert(bio1 != NULL);
 676         assert(bio2 != NULL);
 677
 678         b1 = bio1->ptr;
 679         b2 = bio2->ptr;
 680
 681         if (b1->peer != NULL || b2->peer != NULL) {
 682                 BIOerror(BIO_R_IN_USE);
 683                 return 0;
 684         }
 685
 686         if (b1->buf == NULL) {
 687                 b1->buf = malloc(b1->size);
 688                 if (b1->buf == NULL) {
 689                         BIOerror(ERR_R_MALLOC_FAILURE);
 690                         return 0;
 691                 }
 692                 b1->len = 0;
 693                 b1->offset = 0;
 694         }
 695
 696         if (b2->buf == NULL) {
 697                 b2->buf = malloc(b2->size);
 698                 if (b2->buf == NULL) {
 699                         BIOerror(ERR_R_MALLOC_FAILURE);
 700                         return 0;
 701                 }
 702                 b2->len = 0;
 703                 b2->offset = 0;
 704         }
 705
 706         b1->peer = bio2;
 707         b1->closed = 0;
 708         b1->request = 0;
 709         b2->peer = bio1;
 710         b2->closed = 0;
 711         b2->request = 0;
 712
 713         bio1->init = 1;
 714         bio2->init = 1;
 715
 716         return 1;
 717 }
 718
 719 static void
 720 bio_destroy_pair(BIO *bio)
 721 {
 722         struct bio_bio_st *b = bio->ptr;
 723
 724         if (b != NULL) {
 725                 BIO *peer_bio = b->peer;
 726
 727                 if (peer_bio != NULL) {
 728                         struct bio_bio_st *peer_b = peer_bio->ptr;
 729
 730                         assert(peer_b != NULL);
 731                         assert(peer_b->peer == bio);
 732
 733                         peer_b->peer = NULL;
 734                         peer_bio->init = 0;
 735                         assert(peer_b->buf != NULL);
 736                         peer_b->len = 0;
 737                         peer_b->offset = 0;
 738
 739                         b->peer = NULL;
 740                         bio->init = 0;
 741                         assert(b->buf != NULL);
 742                         b->len = 0;
 743                         b->offset = 0;
 744                 }
 745         }
 746 }
 747
 748
 749 /* Exported convenience functions */
 750 int
 751 BIO_new_bio_pair(BIO **bio1_p, size_t writebuf1, BIO **bio2_p, size_t writebuf2)
 752 {
 753         BIO *bio1 = NULL, *bio2 = NULL;
 754         long r;
 755         int ret = 0;
 756
 757         bio1 = BIO_new(BIO_s_bio());
 758         if (bio1 == NULL)
 759                 goto err;
 760         bio2 = BIO_new(BIO_s_bio());
 761         if (bio2 == NULL)
 762                 goto err;
 763
 764         if (writebuf1) {
 765                 r = BIO_set_write_buf_size(bio1, writebuf1);
 766                 if (!r)
 767                         goto err;
 768         }
 769         if (writebuf2) {
 770                 r = BIO_set_write_buf_size(bio2, writebuf2);
 771                 if (!r)
 772                         goto err;
 773         }
 774
 775         r = BIO_make_bio_pair(bio1, bio2);
 776         if (!r)
 777                 goto err;
 778         ret = 1;
 779
 780         err:
 781         if (ret == 0) {
 782                 if (bio1) {
 783                         BIO_free(bio1);
 784                         bio1 = NULL;
 785                 }
 786                 if (bio2) {
 787                         BIO_free(bio2);
 788                         bio2 = NULL;
 789                 }
 790         }
 791
 792         *bio1_p = bio1;
 793         *bio2_p = bio2;
 794         return ret;
 795 }
 796
 797 size_t
 798 BIO_ctrl_get_write_guarantee(BIO *bio)
 799 {
 800         return BIO_ctrl(bio, BIO_C_GET_WRITE_GUARANTEE, 0, NULL);
 801 }
 802
 803 size_t
 804 BIO_ctrl_get_read_request(BIO *bio)
 805 {
 806         return BIO_ctrl(bio, BIO_C_GET_READ_REQUEST, 0, NULL);
 807 }
 808
 809 int
 810 BIO_ctrl_reset_read_request(BIO *bio)
 811 {
 812         return (BIO_ctrl(bio, BIO_C_RESET_READ_REQUEST, 0, NULL) != 0);
 813 }
 814
 815
 816 /* BIO_nread0/nread/nwrite0/nwrite are available only for BIO pairs for now
 817  * (conceivably some other BIOs could allow non-copying reads and writes too.)
 818  */
 819 int
 820 BIO_nread0(BIO *bio, char **buf)
 821 {
 822         long ret;
 823
 824         if (!bio->init) {
 825                 BIOerror(BIO_R_UNINITIALIZED);
 826                 return -2;
 827         }
 828
 829         ret = BIO_ctrl(bio, BIO_C_NREAD0, 0, buf);
 830         if (ret > INT_MAX)
 831                 return INT_MAX;
 832         else
 833                 return (int) ret;
 834 }
 835
 836 int
 837 BIO_nread(BIO *bio, char **buf, int num)
 838 {
 839         int ret;
 840
 841         if (!bio->init) {
 842                 BIOerror(BIO_R_UNINITIALIZED);
 843                 return -2;
 844         }
 845
 846         ret = (int) BIO_ctrl(bio, BIO_C_NREAD, num, buf);
 847         if (ret > 0)
 848                 bio->num_read += ret;
 849         return ret;
 850 }
 851
 852 int
 853 BIO_nwrite0(BIO *bio, char **buf)
 854 {
 855         long ret;
 856
 857         if (!bio->init) {
 858                 BIOerror(BIO_R_UNINITIALIZED);
 859                 return -2;
 860         }
 861
 862         ret = BIO_ctrl(bio, BIO_C_NWRITE0, 0, buf);
 863         if (ret > INT_MAX)
 864                 return INT_MAX;
 865         else
 866                 return (int) ret;
 867 }
 868
 869 int
 870 BIO_nwrite(BIO *bio, char **buf, int num)
 871 {
 872         int ret;
 873
 874         if (!bio->init) {
 875                 BIOerror(BIO_R_UNINITIALIZED);
 876                 return -2;
 877         }
 878
 879         ret = BIO_ctrl(bio, BIO_C_NWRITE, num, buf);
 880         if (ret > 0)
 881                 bio->num_write += ret;
 882         return ret;
 883 }