1/* ====================================================================
2 * Copyright (c) 1998-2003 The OpenSSL Project.  All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in
13 *    the documentation and/or other materials provided with the
14 *    distribution.
15 *
16 * 3. All advertising materials mentioning features or use of this
17 *    software must display the following acknowledgment:
18 *    "This product includes software developed by the OpenSSL Project
19 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
20 *
21 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
22 *    endorse or promote products derived from this software without
23 *    prior written permission. For written permission, please contact
24 *    openssl-core@openssl.org.
25 *
26 * 5. Products derived from this software may not be called "OpenSSL"
27 *    nor may "OpenSSL" appear in their names without prior written
28 *    permission of the OpenSSL Project.
29 *
30 * 6. Redistributions of any form whatsoever must retain the following
31 *    acknowledgment:
32 *    "This product includes software developed by the OpenSSL Project
33 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
34 *
35 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
36 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
37 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
38 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
39 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
41 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
42 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
43 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
44 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
45 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
46 * OF THE POSSIBILITY OF SUCH DAMAGE.
47 * ====================================================================
48 *
49 * This product includes cryptographic software written by Eric Young
50 * (eay@cryptsoft.com).  This product includes software written by Tim
51 * Hudson (tjh@cryptsoft.com). */
52
53#include <openssl/bio.h>
54
55#include <assert.h>
56#include <string.h>
57
58#include <openssl/buf.h>
59#include <openssl/err.h>
60#include <openssl/mem.h>
61
62#include "../internal.h"
63
64
65struct bio_bio_st {
66  BIO *peer; /* NULL if buf == NULL.
67              * If peer != NULL, then peer->ptr is also a bio_bio_st,
68              * and its "peer" member points back to us.
69              * peer != NULL iff init != 0 in the BIO. */
70
71  /* This is for what we write (i.e. reading uses peer's struct): */
72  int closed;    /* valid iff peer != NULL */
73  size_t len;    /* valid iff buf != NULL; 0 if peer == NULL */
74  size_t offset; /* valid iff buf != NULL; 0 if len == 0 */
75  size_t size;
76  uint8_t *buf; /* "size" elements (if != NULL) */
77
78  size_t request; /* valid iff peer != NULL; 0 if len != 0,
79                   * otherwise set by peer to number of bytes
80                   * it (unsuccessfully) tried to read,
81                   * never more than buffer space (size-len) warrants. */
82};
83
84static int bio_new(BIO *bio) {
85  struct bio_bio_st *b;
86
87  b = OPENSSL_malloc(sizeof *b);
88  if (b == NULL) {
89    return 0;
90  }
91  OPENSSL_memset(b, 0, sizeof(struct bio_bio_st));
92
93  b->size = 17 * 1024; /* enough for one TLS record (just a default) */
94  bio->ptr = b;
95  return 1;
96}
97
98static void bio_destroy_pair(BIO *bio) {
99  struct bio_bio_st *b = bio->ptr;
100  BIO *peer_bio;
101  struct bio_bio_st *peer_b;
102
103  if (b == NULL) {
104    return;
105  }
106
107  peer_bio = b->peer;
108  if (peer_bio == NULL) {
109    return;
110  }
111
112  peer_b = peer_bio->ptr;
113
114  assert(peer_b != NULL);
115  assert(peer_b->peer == bio);
116
117  peer_b->peer = NULL;
118  peer_bio->init = 0;
119  assert(peer_b->buf != NULL);
120  peer_b->len = 0;
121  peer_b->offset = 0;
122
123  b->peer = NULL;
124  bio->init = 0;
125  assert(b->buf != NULL);
126  b->len = 0;
127  b->offset = 0;
128}
129
130static int bio_free(BIO *bio) {
131  struct bio_bio_st *b;
132
133  if (bio == NULL) {
134    return 0;
135  }
136  b = bio->ptr;
137
138  assert(b != NULL);
139
140  if (b->peer) {
141    bio_destroy_pair(bio);
142  }
143
144  OPENSSL_free(b->buf);
145  OPENSSL_free(b);
146
147  return 1;
148}
149
150static int bio_read(BIO *bio, char *buf, int size_) {
151  size_t size = size_;
152  size_t rest;
153  struct bio_bio_st *b, *peer_b;
154
155  BIO_clear_retry_flags(bio);
156
157  if (!bio->init) {
158    return 0;
159  }
160
161  b = bio->ptr;
162  assert(b != NULL);
163  assert(b->peer != NULL);
164  peer_b = b->peer->ptr;
165  assert(peer_b != NULL);
166  assert(peer_b->buf != NULL);
167
168  peer_b->request = 0; /* will be set in "retry_read" situation */
169
170  if (buf == NULL || size == 0) {
171    return 0;
172  }
173
174  if (peer_b->len == 0) {
175    if (peer_b->closed) {
176      return 0; /* writer has closed, and no data is left */
177    } else {
178      BIO_set_retry_read(bio); /* buffer is empty */
179      if (size <= peer_b->size) {
180        peer_b->request = size;
181      } else {
182        /* don't ask for more than the peer can
183         * deliver in one write */
184        peer_b->request = peer_b->size;
185      }
186      return -1;
187    }
188  }
189
190  /* we can read */
191  if (peer_b->len < size) {
192    size = peer_b->len;
193  }
194
195  /* now read "size" bytes */
196  rest = size;
197
198  assert(rest > 0);
199  /* one or two iterations */
200  do {
201    size_t chunk;
202
203    assert(rest <= peer_b->len);
204    if (peer_b->offset + rest <= peer_b->size) {
205      chunk = rest;
206    } else {
207      /* wrap around ring buffer */
208      chunk = peer_b->size - peer_b->offset;
209    }
210    assert(peer_b->offset + chunk <= peer_b->size);
211
212    OPENSSL_memcpy(buf, peer_b->buf + peer_b->offset, chunk);
213
214    peer_b->len -= chunk;
215    if (peer_b->len) {
216      peer_b->offset += chunk;
217      assert(peer_b->offset <= peer_b->size);
218      if (peer_b->offset == peer_b->size) {
219        peer_b->offset = 0;
220      }
221      buf += chunk;
222    } else {
223      /* buffer now empty, no need to advance "buf" */
224      assert(chunk == rest);
225      peer_b->offset = 0;
226    }
227    rest -= chunk;
228  } while (rest);
229
230  return size;
231}
232
233static int bio_write(BIO *bio, const char *buf, int num_) {
234  size_t num = num_;
235  size_t rest;
236  struct bio_bio_st *b;
237
238  BIO_clear_retry_flags(bio);
239
240  if (!bio->init || buf == NULL || num == 0) {
241    return 0;
242  }
243
244  b = bio->ptr;
245  assert(b != NULL);
246  assert(b->peer != NULL);
247  assert(b->buf != NULL);
248
249  b->request = 0;
250  if (b->closed) {
251    /* we already closed */
252    OPENSSL_PUT_ERROR(BIO, BIO_R_BROKEN_PIPE);
253    return -1;
254  }
255
256  assert(b->len <= b->size);
257
258  if (b->len == b->size) {
259    BIO_set_retry_write(bio); /* buffer is full */
260    return -1;
261  }
262
263  /* we can write */
264  if (num > b->size - b->len) {
265    num = b->size - b->len;
266  }
267
268  /* now write "num" bytes */
269  rest = num;
270
271  assert(rest > 0);
272  /* one or two iterations */
273  do {
274    size_t write_offset;
275    size_t chunk;
276
277    assert(b->len + rest <= b->size);
278
279    write_offset = b->offset + b->len;
280    if (write_offset >= b->size) {
281      write_offset -= b->size;
282    }
283    /* b->buf[write_offset] is the first byte we can write to. */
284
285    if (write_offset + rest <= b->size) {
286      chunk = rest;
287    } else {
288      /* wrap around ring buffer */
289      chunk = b->size - write_offset;
290    }
291
292    OPENSSL_memcpy(b->buf + write_offset, buf, chunk);
293
294    b->len += chunk;
295
296    assert(b->len <= b->size);
297
298    rest -= chunk;
299    buf += chunk;
300  } while (rest);
301
302  return num;
303}
304
305static int bio_make_pair(BIO *bio1, BIO *bio2, size_t writebuf1_len,
306                         size_t writebuf2_len) {
307  struct bio_bio_st *b1, *b2;
308
309  assert(bio1 != NULL);
310  assert(bio2 != NULL);
311
312  b1 = bio1->ptr;
313  b2 = bio2->ptr;
314
315  if (b1->peer != NULL || b2->peer != NULL) {
316    OPENSSL_PUT_ERROR(BIO, BIO_R_IN_USE);
317    return 0;
318  }
319
320  if (b1->buf == NULL) {
321    if (writebuf1_len) {
322      b1->size = writebuf1_len;
323    }
324    b1->buf = OPENSSL_malloc(b1->size);
325    if (b1->buf == NULL) {
326      OPENSSL_PUT_ERROR(BIO, ERR_R_MALLOC_FAILURE);
327      return 0;
328    }
329    b1->len = 0;
330    b1->offset = 0;
331  }
332
333  if (b2->buf == NULL) {
334    if (writebuf2_len) {
335      b2->size = writebuf2_len;
336    }
337    b2->buf = OPENSSL_malloc(b2->size);
338    if (b2->buf == NULL) {
339      OPENSSL_PUT_ERROR(BIO, ERR_R_MALLOC_FAILURE);
340      return 0;
341    }
342    b2->len = 0;
343    b2->offset = 0;
344  }
345
346  b1->peer = bio2;
347  b1->closed = 0;
348  b1->request = 0;
349  b2->peer = bio1;
350  b2->closed = 0;
351  b2->request = 0;
352
353  bio1->init = 1;
354  bio2->init = 1;
355
356  return 1;
357}
358
359static long bio_ctrl(BIO *bio, int cmd, long num, void *ptr) {
360  long ret;
361  struct bio_bio_st *b = bio->ptr;
362
363  assert(b != NULL);
364
365  switch (cmd) {
366    /* specific CTRL codes */
367
368    case BIO_C_GET_WRITE_BUF_SIZE:
369      ret = (long)b->size;
370      break;
371
372    case BIO_C_GET_WRITE_GUARANTEE:
373      /* How many bytes can the caller feed to the next write
374       * without having to keep any? */
375      if (b->peer == NULL || b->closed) {
376        ret = 0;
377      } else {
378        ret = (long)b->size - b->len;
379      }
380      break;
381
382    case BIO_C_GET_READ_REQUEST:
383      /* If the peer unsuccessfully tried to read, how many bytes
384       * were requested?  (As with BIO_CTRL_PENDING, that number
385       * can usually be treated as boolean.) */
386      ret = (long)b->request;
387      break;
388
389    case BIO_C_RESET_READ_REQUEST:
390      /* Reset request.  (Can be useful after read attempts
391       * at the other side that are meant to be non-blocking,
392       * e.g. when probing SSL_read to see if any data is
393       * available.) */
394      b->request = 0;
395      ret = 1;
396      break;
397
398    case BIO_C_SHUTDOWN_WR:
399      /* similar to shutdown(..., SHUT_WR) */
400      b->closed = 1;
401      ret = 1;
402      break;
403
404    /* standard CTRL codes follow */
405
406    case BIO_CTRL_GET_CLOSE:
407      ret = bio->shutdown;
408      break;
409
410    case BIO_CTRL_SET_CLOSE:
411      bio->shutdown = (int)num;
412      ret = 1;
413      break;
414
415    case BIO_CTRL_PENDING:
416      if (b->peer != NULL) {
417        struct bio_bio_st *peer_b = b->peer->ptr;
418        ret = (long)peer_b->len;
419      } else {
420        ret = 0;
421      }
422      break;
423
424    case BIO_CTRL_WPENDING:
425      ret = 0;
426      if (b->buf != NULL) {
427        ret = (long)b->len;
428      }
429      break;
430
431    case BIO_CTRL_FLUSH:
432      ret = 1;
433      break;
434
435    case BIO_CTRL_EOF: {
436      BIO *other_bio = ptr;
437
438      if (other_bio) {
439        struct bio_bio_st *other_b = other_bio->ptr;
440        assert(other_b != NULL);
441        ret = other_b->len == 0 && other_b->closed;
442      } else {
443        ret = 1;
444      }
445    } break;
446
447    default:
448      ret = 0;
449  }
450  return ret;
451}
452
453
454static const BIO_METHOD methods_biop = {
455    BIO_TYPE_BIO,    "BIO pair", bio_write, bio_read, NULL /* puts */,
456    NULL /* gets */, bio_ctrl,   bio_new,   bio_free, NULL /* callback_ctrl */
457};
458
459static const BIO_METHOD *bio_s_bio(void) { return &methods_biop; }
460
461int BIO_new_bio_pair(BIO** bio1_p, size_t writebuf1_len,
462                     BIO** bio2_p, size_t writebuf2_len) {
463  BIO *bio1 = BIO_new(bio_s_bio());
464  BIO *bio2 = BIO_new(bio_s_bio());
465  if (bio1 == NULL || bio2 == NULL ||
466      !bio_make_pair(bio1, bio2, writebuf1_len, writebuf2_len)) {
467    BIO_free(bio1);
468    BIO_free(bio2);
469    *bio1_p = NULL;
470    *bio2_p = NULL;
471    return 0;
472  }
473
474  *bio1_p = bio1;
475  *bio2_p = bio2;
476  return 1;
477}
478
479size_t BIO_ctrl_get_read_request(BIO *bio) {
480  return BIO_ctrl(bio, BIO_C_GET_READ_REQUEST, 0, NULL);
481}
482
483size_t BIO_ctrl_get_write_guarantee(BIO *bio) {
484  return BIO_ctrl(bio, BIO_C_GET_WRITE_GUARANTEE, 0, NULL);
485}
486
487int BIO_shutdown_wr(BIO *bio) {
488  return BIO_ctrl(bio, BIO_C_SHUTDOWN_WR, 0, NULL);
489}
490