2 * Copyright 1999-2017 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (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 = {
41 /* TODO: Convert to new style write function */
44 /* TODO: Convert to new style read function */
48 NULL /* no bio_gets */ ,
52 NULL /* no bio_callback_ctrl */
55 const BIO_METHOD *BIO_s_bio(void)
61 BIO *peer; /* NULL if buf == NULL. If peer != NULL, then
62 * peer->ptr is also a bio_bio_st, and its
63 * "peer" member points back to us. peer !=
64 * NULL iff init != 0 in the BIO. */
65 /* This is for what we write (i.e. reading uses peer's struct): */
66 int closed; /* valid iff peer != NULL */
67 size_t len; /* valid iff buf != NULL; 0 if peer == NULL */
68 size_t offset; /* valid iff buf != NULL; 0 if len == 0 */
70 char *buf; /* "size" elements (if != NULL) */
71 size_t request; /* valid iff peer != NULL; 0 if len != 0,
72 * otherwise set by peer to number of bytes
73 * it (unsuccessfully) tried to read, never
74 * more than buffer space (size-len)
78 static int bio_new(BIO *bio)
80 struct bio_bio_st *b = OPENSSL_zalloc(sizeof(*b));
85 /* enough for one TLS record (just a default) */
92 static int bio_free(BIO *bio)
103 bio_destroy_pair(bio);
105 OPENSSL_free(b->buf);
111 static int bio_read(BIO *bio, char *buf, int size_)
115 struct bio_bio_st *b, *peer_b;
117 BIO_clear_retry_flags(bio);
124 assert(b->peer != NULL);
125 peer_b = b->peer->ptr;
126 assert(peer_b != NULL);
127 assert(peer_b->buf != NULL);
129 peer_b->request = 0; /* will be set in "retry_read" situation */
131 if (buf == NULL || size == 0)
134 if (peer_b->len == 0) {
136 return 0; /* writer has closed, and no data is left */
138 BIO_set_retry_read(bio); /* buffer is empty */
139 if (size <= peer_b->size)
140 peer_b->request = size;
143 * don't ask for more than the peer can deliver in one write
145 peer_b->request = peer_b->size;
151 if (peer_b->len < size)
154 /* now read "size" bytes */
159 do { /* one or two iterations */
162 assert(rest <= peer_b->len);
163 if (peer_b->offset + rest <= peer_b->size)
166 /* wrap around ring buffer */
167 chunk = peer_b->size - peer_b->offset;
168 assert(peer_b->offset + chunk <= peer_b->size);
170 memcpy(buf, peer_b->buf + peer_b->offset, chunk);
172 peer_b->len -= chunk;
174 peer_b->offset += chunk;
175 assert(peer_b->offset <= peer_b->size);
176 if (peer_b->offset == peer_b->size)
180 /* buffer now empty, no need to advance "buf" */
181 assert(chunk == rest);
192 * non-copying interface: provide pointer to available data in buffer
193 * bio_nread0: return number of available bytes
194 * bio_nread: also advance index
195 * (example usage: bio_nread0(), read from buffer, bio_nread()
196 * or just bio_nread(), read from buffer)
199 * WARNING: The non-copying interface is largely untested as of yet and may
202 static ossl_ssize_t bio_nread0(BIO *bio, char **buf)
204 struct bio_bio_st *b, *peer_b;
207 BIO_clear_retry_flags(bio);
214 assert(b->peer != NULL);
215 peer_b = b->peer->ptr;
216 assert(peer_b != NULL);
217 assert(peer_b->buf != NULL);
221 if (peer_b->len == 0) {
224 /* avoid code duplication -- nothing available for reading */
225 return bio_read(bio, &dummy, 1); /* returns 0 or -1 */
229 if (peer_b->size < peer_b->offset + num)
230 /* no ring buffer wrap-around for non-copying interface */
231 num = peer_b->size - peer_b->offset;
235 *buf = peer_b->buf + peer_b->offset;
239 static ossl_ssize_t bio_nread(BIO *bio, char **buf, size_t num_)
241 struct bio_bio_st *b, *peer_b;
242 ossl_ssize_t num, available;
244 if (num_ > OSSL_SSIZE_MAX)
245 num = OSSL_SSIZE_MAX;
247 num = (ossl_ssize_t) num_;
249 available = bio_nread0(bio, buf);
256 peer_b = b->peer->ptr;
260 peer_b->offset += num;
261 assert(peer_b->offset <= peer_b->size);
262 if (peer_b->offset == peer_b->size)
270 static int bio_write(BIO *bio, const char *buf, int num_)
274 struct bio_bio_st *b;
276 BIO_clear_retry_flags(bio);
278 if (!bio->init || buf == NULL || num == 0)
283 assert(b->peer != NULL);
284 assert(b->buf != NULL);
288 /* we already closed */
289 BIOerr(BIO_F_BIO_WRITE, BIO_R_BROKEN_PIPE);
293 assert(b->len <= b->size);
295 if (b->len == b->size) {
296 BIO_set_retry_write(bio); /* buffer is full */
301 if (num > b->size - b->len)
302 num = b->size - b->len;
304 /* now write "num" bytes */
309 do { /* one or two iterations */
313 assert(b->len + rest <= b->size);
315 write_offset = b->offset + b->len;
316 if (write_offset >= b->size)
317 write_offset -= b->size;
318 /* b->buf[write_offset] is the first byte we can write to. */
320 if (write_offset + rest <= b->size)
323 /* wrap around ring buffer */
324 chunk = b->size - write_offset;
326 memcpy(b->buf + write_offset, buf, chunk);
330 assert(b->len <= b->size);
341 * non-copying interface: provide pointer to region to write to
342 * bio_nwrite0: check how much space is available
343 * bio_nwrite: also increase length
344 * (example usage: bio_nwrite0(), write to buffer, bio_nwrite()
345 * or just bio_nwrite(), write to buffer)
347 static ossl_ssize_t bio_nwrite0(BIO *bio, char **buf)
349 struct bio_bio_st *b;
353 BIO_clear_retry_flags(bio);
360 assert(b->peer != NULL);
361 assert(b->buf != NULL);
365 BIOerr(BIO_F_BIO_NWRITE0, BIO_R_BROKEN_PIPE);
369 assert(b->len <= b->size);
371 if (b->len == b->size) {
372 BIO_set_retry_write(bio);
376 num = b->size - b->len;
377 write_offset = b->offset + b->len;
378 if (write_offset >= b->size)
379 write_offset -= b->size;
380 if (write_offset + num > b->size)
382 * no ring buffer wrap-around for non-copying interface (to fulfil
383 * the promise by BIO_ctrl_get_write_guarantee, BIO_nwrite may have
384 * to be called twice)
386 num = b->size - write_offset;
389 *buf = b->buf + write_offset;
390 assert(write_offset + num <= b->size);
395 static ossl_ssize_t bio_nwrite(BIO *bio, char **buf, size_t num_)
397 struct bio_bio_st *b;
398 ossl_ssize_t num, space;
400 if (num_ > OSSL_SSIZE_MAX)
401 num = OSSL_SSIZE_MAX;
403 num = (ossl_ssize_t) num_;
405 space = bio_nwrite0(bio, buf);
413 assert(b->len <= b->size);
418 static long bio_ctrl(BIO *bio, int cmd, long num, void *ptr)
421 struct bio_bio_st *b = bio->ptr;
426 /* specific CTRL codes */
428 case BIO_C_SET_WRITE_BUF_SIZE:
430 BIOerr(BIO_F_BIO_CTRL, BIO_R_IN_USE);
432 } else if (num == 0) {
433 BIOerr(BIO_F_BIO_CTRL, BIO_R_INVALID_ARGUMENT);
436 size_t new_size = num;
438 if (b->size != new_size) {
439 OPENSSL_free(b->buf);
447 case BIO_C_GET_WRITE_BUF_SIZE:
451 case BIO_C_MAKE_BIO_PAIR:
453 BIO *other_bio = ptr;
455 if (bio_make_pair(bio, other_bio))
462 case BIO_C_DESTROY_BIO_PAIR:
464 * Affects both BIOs in the pair -- call just once! Or let
465 * BIO_free(bio1); BIO_free(bio2); do the job.
467 bio_destroy_pair(bio);
471 case BIO_C_GET_WRITE_GUARANTEE:
473 * How many bytes can the caller feed to the next write without
474 * having to keep any?
476 if (b->peer == NULL || b->closed)
479 ret = (long)b->size - b->len;
482 case BIO_C_GET_READ_REQUEST:
484 * If the peer unsuccessfully tried to read, how many bytes were
485 * requested? (As with BIO_CTRL_PENDING, that number can usually be
486 * treated as boolean.)
488 ret = (long)b->request;
491 case BIO_C_RESET_READ_REQUEST:
493 * Reset request. (Can be useful after read attempts at the other
494 * side that are meant to be non-blocking, e.g. when probing SSL_read
495 * to see if any data is available.)
501 case BIO_C_SHUTDOWN_WR:
502 /* similar to shutdown(..., SHUT_WR) */
508 /* prepare for non-copying read */
509 ret = (long)bio_nread0(bio, ptr);
513 /* non-copying read */
514 ret = (long)bio_nread(bio, ptr, (size_t)num);
518 /* prepare for non-copying write */
519 ret = (long)bio_nwrite0(bio, ptr);
523 /* non-copying write */
524 ret = (long)bio_nwrite(bio, ptr, (size_t)num);
527 /* standard CTRL codes follow */
530 if (b->buf != NULL) {
537 case BIO_CTRL_GET_CLOSE:
541 case BIO_CTRL_SET_CLOSE:
542 bio->shutdown = (int)num;
546 case BIO_CTRL_PENDING:
547 if (b->peer != NULL) {
548 struct bio_bio_st *peer_b = b->peer->ptr;
550 ret = (long)peer_b->len;
555 case BIO_CTRL_WPENDING:
563 /* See BIO_dup_chain for circumstances we have to expect. */
565 BIO *other_bio = ptr;
566 struct bio_bio_st *other_b;
568 assert(other_bio != NULL);
569 other_b = other_bio->ptr;
570 assert(other_b != NULL);
572 assert(other_b->buf == NULL); /* other_bio is always fresh */
574 other_b->size = b->size;
585 if (b->peer != NULL) {
586 struct bio_bio_st *peer_b = b->peer->ptr;
588 if (peer_b->len == 0 && peer_b->closed)
603 static int bio_puts(BIO *bio, const char *str)
605 return bio_write(bio, str, strlen(str));
608 static int bio_make_pair(BIO *bio1, BIO *bio2)
610 struct bio_bio_st *b1, *b2;
612 assert(bio1 != NULL);
613 assert(bio2 != NULL);
618 if (b1->peer != NULL || b2->peer != NULL) {
619 BIOerr(BIO_F_BIO_MAKE_PAIR, BIO_R_IN_USE);
623 if (b1->buf == NULL) {
624 b1->buf = OPENSSL_malloc(b1->size);
625 if (b1->buf == NULL) {
626 BIOerr(BIO_F_BIO_MAKE_PAIR, ERR_R_MALLOC_FAILURE);
633 if (b2->buf == NULL) {
634 b2->buf = OPENSSL_malloc(b2->size);
635 if (b2->buf == NULL) {
636 BIOerr(BIO_F_BIO_MAKE_PAIR, ERR_R_MALLOC_FAILURE);
656 static void bio_destroy_pair(BIO *bio)
658 struct bio_bio_st *b = bio->ptr;
661 BIO *peer_bio = b->peer;
663 if (peer_bio != NULL) {
664 struct bio_bio_st *peer_b = peer_bio->ptr;
666 assert(peer_b != NULL);
667 assert(peer_b->peer == bio);
671 assert(peer_b->buf != NULL);
677 assert(b->buf != NULL);
684 /* Exported convenience functions */
685 int BIO_new_bio_pair(BIO **bio1_p, size_t writebuf1,
686 BIO **bio2_p, size_t writebuf2)
688 BIO *bio1 = NULL, *bio2 = NULL;
692 bio1 = BIO_new(BIO_s_bio());
695 bio2 = BIO_new(BIO_s_bio());
700 r = BIO_set_write_buf_size(bio1, writebuf1);
705 r = BIO_set_write_buf_size(bio2, writebuf2);
710 r = BIO_make_bio_pair(bio1, bio2);
728 size_t BIO_ctrl_get_write_guarantee(BIO *bio)
730 return BIO_ctrl(bio, BIO_C_GET_WRITE_GUARANTEE, 0, NULL);
733 size_t BIO_ctrl_get_read_request(BIO *bio)
735 return BIO_ctrl(bio, BIO_C_GET_READ_REQUEST, 0, NULL);
738 int BIO_ctrl_reset_read_request(BIO *bio)
740 return (BIO_ctrl(bio, BIO_C_RESET_READ_REQUEST, 0, NULL) != 0);
744 * BIO_nread0/nread/nwrite0/nwrite are available only for BIO pairs for now
745 * (conceivably some other BIOs could allow non-copying reads and writes
748 int BIO_nread0(BIO *bio, char **buf)
753 BIOerr(BIO_F_BIO_NREAD0, BIO_R_UNINITIALIZED);
757 ret = BIO_ctrl(bio, BIO_C_NREAD0, 0, buf);
764 int BIO_nread(BIO *bio, char **buf, int num)
769 BIOerr(BIO_F_BIO_NREAD, BIO_R_UNINITIALIZED);
773 ret = (int)BIO_ctrl(bio, BIO_C_NREAD, num, buf);
775 bio->num_read += ret;
779 int BIO_nwrite0(BIO *bio, char **buf)
784 BIOerr(BIO_F_BIO_NWRITE0, BIO_R_UNINITIALIZED);
788 ret = BIO_ctrl(bio, BIO_C_NWRITE0, 0, buf);
795 int BIO_nwrite(BIO *bio, char **buf, int num)
800 BIOerr(BIO_F_BIO_NWRITE, BIO_R_UNINITIALIZED);
804 ret = BIO_ctrl(bio, BIO_C_NWRITE, num, buf);
806 bio->num_write += ret;