2 * Copyright 1999-2021 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
11 * Special method for a BIO where the other endpoint is also a BIO of this
12 * kind, handled by the same thread (i.e. the "peer" is actually ourselves,
13 * wearing a different hat). Such "BIO pairs" are mainly for using the SSL
14 * library with I/O interfaces for which no specific BIO method is available.
15 * See ssl/ssltest.c for some hints on how this can be used.
24 #include "bio_local.h"
25 #include <openssl/err.h>
26 #include <openssl/crypto.h>
28 static int bio_new(BIO *bio);
29 static int bio_free(BIO *bio);
30 static int bio_read(BIO *bio, char *buf, int size);
31 static int bio_write(BIO *bio, const char *buf, int num);
32 static long bio_ctrl(BIO *bio, int cmd, long num, void *ptr);
33 static int bio_puts(BIO *bio, const char *str);
35 static int bio_make_pair(BIO *bio1, BIO *bio2);
36 static void bio_destroy_pair(BIO *bio);
38 static const BIO_METHOD methods_biop = {
46 NULL /* no bio_gets */ ,
50 NULL /* no bio_callback_ctrl */
53 const BIO_METHOD *BIO_s_bio(void)
59 BIO *peer; /* NULL if buf == NULL. If peer != NULL, then
60 * peer->ptr is also a bio_bio_st, and its
61 * "peer" member points back to us. peer !=
62 * NULL iff init != 0 in the BIO. */
63 /* This is for what we write (i.e. reading uses peer's struct): */
64 int closed; /* valid iff peer != NULL */
65 size_t len; /* valid iff buf != NULL; 0 if peer == NULL */
66 size_t offset; /* valid iff buf != NULL; 0 if len == 0 */
68 char *buf; /* "size" elements (if != NULL) */
69 size_t request; /* valid iff peer != NULL; 0 if len != 0,
70 * otherwise set by peer to number of bytes
71 * it (unsuccessfully) tried to read, never
72 * more than buffer space (size-len)
76 static int bio_new(BIO *bio)
78 struct bio_bio_st *b = OPENSSL_zalloc(sizeof(*b));
83 /* enough for one TLS record (just a default) */
90 static int bio_free(BIO *bio)
101 bio_destroy_pair(bio);
103 OPENSSL_free(b->buf);
109 static int bio_read(BIO *bio, char *buf, int size_)
113 struct bio_bio_st *b, *peer_b;
115 BIO_clear_retry_flags(bio);
122 assert(b->peer != NULL);
123 peer_b = b->peer->ptr;
124 assert(peer_b != NULL);
125 assert(peer_b->buf != NULL);
127 peer_b->request = 0; /* will be set in "retry_read" situation */
129 if (buf == NULL || size == 0)
132 if (peer_b->len == 0) {
134 return 0; /* writer has closed, and no data is left */
136 BIO_set_retry_read(bio); /* buffer is empty */
137 if (size <= peer_b->size)
138 peer_b->request = size;
141 * don't ask for more than the peer can deliver in one write
143 peer_b->request = peer_b->size;
149 if (peer_b->len < size)
152 /* now read "size" bytes */
157 do { /* one or two iterations */
160 assert(rest <= peer_b->len);
161 if (peer_b->offset + rest <= peer_b->size)
164 /* wrap around ring buffer */
165 chunk = peer_b->size - peer_b->offset;
166 assert(peer_b->offset + chunk <= peer_b->size);
168 memcpy(buf, peer_b->buf + peer_b->offset, chunk);
170 peer_b->len -= chunk;
172 peer_b->offset += chunk;
173 assert(peer_b->offset <= peer_b->size);
174 if (peer_b->offset == peer_b->size)
178 /* buffer now empty, no need to advance "buf" */
179 assert(chunk == rest);
190 * non-copying interface: provide pointer to available data in buffer
191 * bio_nread0: return number of available bytes
192 * bio_nread: also advance index
193 * (example usage: bio_nread0(), read from buffer, bio_nread()
194 * or just bio_nread(), read from buffer)
197 * WARNING: The non-copying interface is largely untested as of yet and may
200 static ossl_ssize_t bio_nread0(BIO *bio, char **buf)
202 struct bio_bio_st *b, *peer_b;
205 BIO_clear_retry_flags(bio);
212 assert(b->peer != NULL);
213 peer_b = b->peer->ptr;
214 assert(peer_b != NULL);
215 assert(peer_b->buf != NULL);
219 if (peer_b->len == 0) {
222 /* avoid code duplication -- nothing available for reading */
223 return bio_read(bio, &dummy, 1); /* returns 0 or -1 */
227 if (peer_b->size < peer_b->offset + num)
228 /* no ring buffer wrap-around for non-copying interface */
229 num = peer_b->size - peer_b->offset;
233 *buf = peer_b->buf + peer_b->offset;
237 static ossl_ssize_t bio_nread(BIO *bio, char **buf, size_t num_)
239 struct bio_bio_st *b, *peer_b;
240 ossl_ssize_t num, available;
242 if (num_ > OSSL_SSIZE_MAX)
243 num = OSSL_SSIZE_MAX;
245 num = (ossl_ssize_t) num_;
247 available = bio_nread0(bio, buf);
254 peer_b = b->peer->ptr;
258 peer_b->offset += num;
259 assert(peer_b->offset <= peer_b->size);
260 if (peer_b->offset == peer_b->size)
268 static int bio_write(BIO *bio, const char *buf, int num_)
272 struct bio_bio_st *b;
274 BIO_clear_retry_flags(bio);
276 if (!bio->init || buf == NULL || num == 0)
281 assert(b->peer != NULL);
282 assert(b->buf != NULL);
286 /* we already closed */
287 ERR_raise(ERR_LIB_BIO, BIO_R_BROKEN_PIPE);
291 assert(b->len <= b->size);
293 if (b->len == b->size) {
294 BIO_set_retry_write(bio); /* buffer is full */
299 if (num > b->size - b->len)
300 num = b->size - b->len;
302 /* now write "num" bytes */
307 do { /* one or two iterations */
311 assert(b->len + rest <= b->size);
313 write_offset = b->offset + b->len;
314 if (write_offset >= b->size)
315 write_offset -= b->size;
316 /* b->buf[write_offset] is the first byte we can write to. */
318 if (write_offset + rest <= b->size)
321 /* wrap around ring buffer */
322 chunk = b->size - write_offset;
324 memcpy(b->buf + write_offset, buf, chunk);
328 assert(b->len <= b->size);
339 * non-copying interface: provide pointer to region to write to
340 * bio_nwrite0: check how much space is available
341 * bio_nwrite: also increase length
342 * (example usage: bio_nwrite0(), write to buffer, bio_nwrite()
343 * or just bio_nwrite(), write to buffer)
345 static ossl_ssize_t bio_nwrite0(BIO *bio, char **buf)
347 struct bio_bio_st *b;
351 BIO_clear_retry_flags(bio);
358 assert(b->peer != NULL);
359 assert(b->buf != NULL);
363 ERR_raise(ERR_LIB_BIO, BIO_R_BROKEN_PIPE);
367 assert(b->len <= b->size);
369 if (b->len == b->size) {
370 BIO_set_retry_write(bio);
374 num = b->size - b->len;
375 write_offset = b->offset + b->len;
376 if (write_offset >= b->size)
377 write_offset -= b->size;
378 if (write_offset + num > b->size)
380 * no ring buffer wrap-around for non-copying interface (to fulfil
381 * the promise by BIO_ctrl_get_write_guarantee, BIO_nwrite may have
382 * to be called twice)
384 num = b->size - write_offset;
387 *buf = b->buf + write_offset;
388 assert(write_offset + num <= b->size);
393 static ossl_ssize_t bio_nwrite(BIO *bio, char **buf, size_t num_)
395 struct bio_bio_st *b;
396 ossl_ssize_t num, space;
398 if (num_ > OSSL_SSIZE_MAX)
399 num = OSSL_SSIZE_MAX;
401 num = (ossl_ssize_t) num_;
403 space = bio_nwrite0(bio, buf);
411 assert(b->len <= b->size);
416 static long bio_ctrl(BIO *bio, int cmd, long num, void *ptr)
419 struct bio_bio_st *b = bio->ptr;
424 /* specific CTRL codes */
426 case BIO_C_SET_WRITE_BUF_SIZE:
428 ERR_raise(ERR_LIB_BIO, BIO_R_IN_USE);
430 } else if (num == 0) {
431 ERR_raise(ERR_LIB_BIO, BIO_R_INVALID_ARGUMENT);
434 size_t new_size = num;
436 if (b->size != new_size) {
437 OPENSSL_free(b->buf);
445 case BIO_C_GET_WRITE_BUF_SIZE:
449 case BIO_C_MAKE_BIO_PAIR:
451 BIO *other_bio = ptr;
453 if (bio_make_pair(bio, other_bio))
460 case BIO_C_DESTROY_BIO_PAIR:
462 * Affects both BIOs in the pair -- call just once! Or let
463 * BIO_free(bio1); BIO_free(bio2); do the job.
465 bio_destroy_pair(bio);
469 case BIO_C_GET_WRITE_GUARANTEE:
471 * How many bytes can the caller feed to the next write without
472 * having to keep any?
474 if (b->peer == NULL || b->closed)
477 ret = (long)b->size - b->len;
480 case BIO_C_GET_READ_REQUEST:
482 * If the peer unsuccessfully tried to read, how many bytes were
483 * requested? (As with BIO_CTRL_PENDING, that number can usually be
484 * treated as boolean.)
486 ret = (long)b->request;
489 case BIO_C_RESET_READ_REQUEST:
491 * Reset request. (Can be useful after read attempts at the other
492 * side that are meant to be non-blocking, e.g. when probing SSL_read
493 * to see if any data is available.)
499 case BIO_C_SHUTDOWN_WR:
500 /* similar to shutdown(..., SHUT_WR) */
506 /* prepare for non-copying read */
507 ret = (long)bio_nread0(bio, ptr);
511 /* non-copying read */
512 ret = (long)bio_nread(bio, ptr, (size_t)num);
516 /* prepare for non-copying write */
517 ret = (long)bio_nwrite0(bio, ptr);
521 /* non-copying write */
522 ret = (long)bio_nwrite(bio, ptr, (size_t)num);
525 /* standard CTRL codes follow */
528 if (b->buf != NULL) {
535 case BIO_CTRL_GET_CLOSE:
539 case BIO_CTRL_SET_CLOSE:
540 bio->shutdown = (int)num;
544 case BIO_CTRL_PENDING:
545 if (b->peer != NULL) {
546 struct bio_bio_st *peer_b = b->peer->ptr;
548 ret = (long)peer_b->len;
553 case BIO_CTRL_WPENDING:
561 /* See BIO_dup_chain for circumstances we have to expect. */
563 BIO *other_bio = ptr;
564 struct bio_bio_st *other_b;
566 assert(other_bio != NULL);
567 other_b = other_bio->ptr;
568 assert(other_b != NULL);
570 assert(other_b->buf == NULL); /* other_bio is always fresh */
572 other_b->size = b->size;
583 if (b->peer != NULL) {
584 struct bio_bio_st *peer_b = b->peer->ptr;
586 if (peer_b->len == 0 && peer_b->closed)
601 static int bio_puts(BIO *bio, const char *str)
603 return bio_write(bio, str, strlen(str));
606 static int bio_make_pair(BIO *bio1, BIO *bio2)
608 struct bio_bio_st *b1, *b2;
610 assert(bio1 != NULL);
611 assert(bio2 != NULL);
616 if (b1->peer != NULL || b2->peer != NULL) {
617 ERR_raise(ERR_LIB_BIO, BIO_R_IN_USE);
621 if (b1->buf == NULL) {
622 b1->buf = OPENSSL_malloc(b1->size);
623 if (b1->buf == NULL) {
624 ERR_raise(ERR_LIB_BIO, ERR_R_MALLOC_FAILURE);
631 if (b2->buf == NULL) {
632 b2->buf = OPENSSL_malloc(b2->size);
633 if (b2->buf == NULL) {
634 ERR_raise(ERR_LIB_BIO, ERR_R_MALLOC_FAILURE);
654 static void bio_destroy_pair(BIO *bio)
656 struct bio_bio_st *b = bio->ptr;
659 BIO *peer_bio = b->peer;
661 if (peer_bio != NULL) {
662 struct bio_bio_st *peer_b = peer_bio->ptr;
664 assert(peer_b != NULL);
665 assert(peer_b->peer == bio);
669 assert(peer_b->buf != NULL);
675 assert(b->buf != NULL);
682 /* Exported convenience functions */
683 int BIO_new_bio_pair(BIO **bio1_p, size_t writebuf1,
684 BIO **bio2_p, size_t writebuf2)
686 BIO *bio1 = NULL, *bio2 = NULL;
690 bio1 = BIO_new(BIO_s_bio());
693 bio2 = BIO_new(BIO_s_bio());
698 r = BIO_set_write_buf_size(bio1, writebuf1);
703 r = BIO_set_write_buf_size(bio2, writebuf2);
708 r = BIO_make_bio_pair(bio1, bio2);
726 size_t BIO_ctrl_get_write_guarantee(BIO *bio)
728 return BIO_ctrl(bio, BIO_C_GET_WRITE_GUARANTEE, 0, NULL);
731 size_t BIO_ctrl_get_read_request(BIO *bio)
733 return BIO_ctrl(bio, BIO_C_GET_READ_REQUEST, 0, NULL);
736 int BIO_ctrl_reset_read_request(BIO *bio)
738 return (BIO_ctrl(bio, BIO_C_RESET_READ_REQUEST, 0, NULL) != 0);
742 * BIO_nread0/nread/nwrite0/nwrite are available only for BIO pairs for now
743 * (conceivably some other BIOs could allow non-copying reads and writes
746 int BIO_nread0(BIO *bio, char **buf)
751 ERR_raise(ERR_LIB_BIO, BIO_R_UNINITIALIZED);
755 ret = BIO_ctrl(bio, BIO_C_NREAD0, 0, buf);
762 int BIO_nread(BIO *bio, char **buf, int num)
767 ERR_raise(ERR_LIB_BIO, BIO_R_UNINITIALIZED);
771 ret = (int)BIO_ctrl(bio, BIO_C_NREAD, num, buf);
773 bio->num_read += ret;
777 int BIO_nwrite0(BIO *bio, char **buf)
782 ERR_raise(ERR_LIB_BIO, BIO_R_UNINITIALIZED);
786 ret = BIO_ctrl(bio, BIO_C_NWRITE0, 0, buf);
793 int BIO_nwrite(BIO *bio, char **buf, int num)
798 ERR_raise(ERR_LIB_BIO, BIO_R_UNINITIALIZED);
802 ret = BIO_ctrl(bio, BIO_C_NWRITE, num, buf);
804 bio->num_write += ret;