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openssl/crypto/bio/bss_bio.c

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/*
* Copyright 1999-2017 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
/*
* Special method for a BIO where the other endpoint is also a BIO of this
* kind, handled by the same thread (i.e. the "peer" is actually ourselves,
* wearing a different hat). Such "BIO pairs" are mainly for using the SSL
* library with I/O interfaces for which no specific BIO method is available.
* See ssl/ssltest.c for some hints on how this can be used.
*/
#include "e_os.h"
#include <assert.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include "bio_local.h"
#include <openssl/err.h>
#include <openssl/crypto.h>
static int bio_new(BIO *bio);
static int bio_free(BIO *bio);
static int bio_read(BIO *bio, char *buf, int size);
static int bio_write(BIO *bio, const char *buf, int num);
static long bio_ctrl(BIO *bio, int cmd, long num, void *ptr);
static int bio_puts(BIO *bio, const char *str);
static int bio_make_pair(BIO *bio1, BIO *bio2);
static void bio_destroy_pair(BIO *bio);
static const BIO_METHOD methods_biop = {
BIO_TYPE_BIO,
"BIO pair",
/* TODO: Convert to new style write function */
bwrite_conv,
bio_write,
/* TODO: Convert to new style read function */
bread_conv,
bio_read,
bio_puts,
NULL /* no bio_gets */ ,
bio_ctrl,
bio_new,
bio_free,
NULL /* no bio_callback_ctrl */
};
const BIO_METHOD *BIO_s_bio(void)
{
return &methods_biop;
}
struct bio_bio_st {
BIO *peer; /* NULL if buf == NULL. If peer != NULL, then
* peer->ptr is also a bio_bio_st, and its
* "peer" member points back to us. peer !=
* NULL iff init != 0 in the BIO. */
/* This is for what we write (i.e. reading uses peer's struct): */
int closed; /* valid iff peer != NULL */
size_t len; /* valid iff buf != NULL; 0 if peer == NULL */
size_t offset; /* valid iff buf != NULL; 0 if len == 0 */
size_t size;
char *buf; /* "size" elements (if != NULL) */
size_t request; /* valid iff peer != NULL; 0 if len != 0,
* otherwise set by peer to number of bytes
* it (unsuccessfully) tried to read, never
* more than buffer space (size-len)
* warrants. */
};
static int bio_new(BIO *bio)
{
struct bio_bio_st *b = OPENSSL_zalloc(sizeof(*b));
if (b == NULL)
return 0;
/* enough for one TLS record (just a default) */
b->size = 17 * 1024;
bio->ptr = b;
return 1;
}
static int bio_free(BIO *bio)
{
struct bio_bio_st *b;
if (bio == NULL)
return 0;
b = bio->ptr;
assert(b != NULL);
if (b->peer)
bio_destroy_pair(bio);
OPENSSL_free(b->buf);
OPENSSL_free(b);
return 1;
}
static int bio_read(BIO *bio, char *buf, int size_)
{
size_t size = size_;
size_t rest;
struct bio_bio_st *b, *peer_b;
BIO_clear_retry_flags(bio);
if (!bio->init)
return 0;
b = bio->ptr;
assert(b != NULL);
assert(b->peer != NULL);
peer_b = b->peer->ptr;
assert(peer_b != NULL);
assert(peer_b->buf != NULL);
peer_b->request = 0; /* will be set in "retry_read" situation */
if (buf == NULL || size == 0)
return 0;
if (peer_b->len == 0) {
if (peer_b->closed)
return 0; /* writer has closed, and no data is left */
else {
BIO_set_retry_read(bio); /* buffer is empty */
if (size <= peer_b->size)
peer_b->request = size;
else
/*
* don't ask for more than the peer can deliver in one write
*/
peer_b->request = peer_b->size;
return -1;
}
}
/* we can read */
if (peer_b->len < size)
size = peer_b->len;
/* now read "size" bytes */
rest = size;
assert(rest > 0);
do { /* one or two iterations */
size_t chunk;
assert(rest <= peer_b->len);
if (peer_b->offset + rest <= peer_b->size)
chunk = rest;
else
/* wrap around ring buffer */
chunk = peer_b->size - peer_b->offset;
assert(peer_b->offset + chunk <= peer_b->size);
memcpy(buf, peer_b->buf + peer_b->offset, chunk);
peer_b->len -= chunk;
if (peer_b->len) {
peer_b->offset += chunk;
assert(peer_b->offset <= peer_b->size);
if (peer_b->offset == peer_b->size)
peer_b->offset = 0;
buf += chunk;
} else {
/* buffer now empty, no need to advance "buf" */
assert(chunk == rest);
peer_b->offset = 0;
}
rest -= chunk;
}
while (rest);
return size;
}
/*-
* non-copying interface: provide pointer to available data in buffer
* bio_nread0: return number of available bytes
* bio_nread: also advance index
* (example usage: bio_nread0(), read from buffer, bio_nread()
* or just bio_nread(), read from buffer)
*/
/*
* WARNING: The non-copying interface is largely untested as of yet and may
* contain bugs.
*/
static ossl_ssize_t bio_nread0(BIO *bio, char **buf)
{
struct bio_bio_st *b, *peer_b;
ossl_ssize_t num;
BIO_clear_retry_flags(bio);
if (!bio->init)
return 0;
b = bio->ptr;
assert(b != NULL);
assert(b->peer != NULL);
peer_b = b->peer->ptr;
assert(peer_b != NULL);
assert(peer_b->buf != NULL);
peer_b->request = 0;
if (peer_b->len == 0) {
char dummy;
/* avoid code duplication -- nothing available for reading */
return bio_read(bio, &dummy, 1); /* returns 0 or -1 */
}
num = peer_b->len;
if (peer_b->size < peer_b->offset + num)
/* no ring buffer wrap-around for non-copying interface */
num = peer_b->size - peer_b->offset;
assert(num > 0);
if (buf != NULL)
*buf = peer_b->buf + peer_b->offset;
return num;
}
static ossl_ssize_t bio_nread(BIO *bio, char **buf, size_t num_)
{
struct bio_bio_st *b, *peer_b;
ossl_ssize_t num, available;
if (num_ > OSSL_SSIZE_MAX)
num = OSSL_SSIZE_MAX;
else
num = (ossl_ssize_t) num_;
available = bio_nread0(bio, buf);
if (num > available)
num = available;
if (num <= 0)
return num;
b = bio->ptr;
peer_b = b->peer->ptr;
peer_b->len -= num;
if (peer_b->len) {
peer_b->offset += num;
assert(peer_b->offset <= peer_b->size);
if (peer_b->offset == peer_b->size)
peer_b->offset = 0;
} else
peer_b->offset = 0;
return num;
}
static int bio_write(BIO *bio, const char *buf, int num_)
{
size_t num = num_;
size_t rest;
struct bio_bio_st *b;
BIO_clear_retry_flags(bio);
if (!bio->init || buf == NULL || num == 0)
return 0;
b = bio->ptr;
assert(b != NULL);
assert(b->peer != NULL);
assert(b->buf != NULL);
b->request = 0;
if (b->closed) {
/* we already closed */
BIOerr(BIO_F_BIO_WRITE, BIO_R_BROKEN_PIPE);
return -1;
}
assert(b->len <= b->size);
if (b->len == b->size) {
BIO_set_retry_write(bio); /* buffer is full */
return -1;
}
/* we can write */
if (num > b->size - b->len)
num = b->size - b->len;
/* now write "num" bytes */
rest = num;
assert(rest > 0);
do { /* one or two iterations */
size_t write_offset;
size_t chunk;
assert(b->len + rest <= b->size);
write_offset = b->offset + b->len;
if (write_offset >= b->size)
write_offset -= b->size;
/* b->buf[write_offset] is the first byte we can write to. */
if (write_offset + rest <= b->size)
chunk = rest;
else
/* wrap around ring buffer */
chunk = b->size - write_offset;
memcpy(b->buf + write_offset, buf, chunk);
b->len += chunk;
assert(b->len <= b->size);
rest -= chunk;
buf += chunk;
}
while (rest);
return num;
}
/*-
* non-copying interface: provide pointer to region to write to
* bio_nwrite0: check how much space is available
* bio_nwrite: also increase length
* (example usage: bio_nwrite0(), write to buffer, bio_nwrite()
* or just bio_nwrite(), write to buffer)
*/
static ossl_ssize_t bio_nwrite0(BIO *bio, char **buf)
{
struct bio_bio_st *b;
size_t num;
size_t write_offset;
BIO_clear_retry_flags(bio);
if (!bio->init)
return 0;
b = bio->ptr;
assert(b != NULL);
assert(b->peer != NULL);
assert(b->buf != NULL);
b->request = 0;
if (b->closed) {
BIOerr(BIO_F_BIO_NWRITE0, BIO_R_BROKEN_PIPE);
return -1;
}
assert(b->len <= b->size);
if (b->len == b->size) {
BIO_set_retry_write(bio);
return -1;
}
num = b->size - b->len;
write_offset = b->offset + b->len;
if (write_offset >= b->size)
write_offset -= b->size;
if (write_offset + num > b->size)
/*
* no ring buffer wrap-around for non-copying interface (to fulfil
* the promise by BIO_ctrl_get_write_guarantee, BIO_nwrite may have
* to be called twice)
*/
num = b->size - write_offset;
if (buf != NULL)
*buf = b->buf + write_offset;
assert(write_offset + num <= b->size);
return num;
}
static ossl_ssize_t bio_nwrite(BIO *bio, char **buf, size_t num_)
{
struct bio_bio_st *b;
ossl_ssize_t num, space;
if (num_ > OSSL_SSIZE_MAX)
num = OSSL_SSIZE_MAX;
else
num = (ossl_ssize_t) num_;
space = bio_nwrite0(bio, buf);
if (num > space)
num = space;
if (num <= 0)
return num;
b = bio->ptr;
assert(b != NULL);
b->len += num;
assert(b->len <= b->size);
return num;
}
static long bio_ctrl(BIO *bio, int cmd, long num, void *ptr)
{
long ret;
struct bio_bio_st *b = bio->ptr;
assert(b != NULL);
switch (cmd) {
/* specific CTRL codes */
case BIO_C_SET_WRITE_BUF_SIZE:
if (b->peer) {
BIOerr(BIO_F_BIO_CTRL, BIO_R_IN_USE);
ret = 0;
} else if (num == 0) {
BIOerr(BIO_F_BIO_CTRL, BIO_R_INVALID_ARGUMENT);
ret = 0;
} else {
size_t new_size = num;
if (b->size != new_size) {
OPENSSL_free(b->buf);
b->buf = NULL;
b->size = new_size;
}
ret = 1;
}
break;
case BIO_C_GET_WRITE_BUF_SIZE:
ret = (long)b->size;
break;
case BIO_C_MAKE_BIO_PAIR:
{
BIO *other_bio = ptr;
if (bio_make_pair(bio, other_bio))
ret = 1;
else
ret = 0;
}
break;
case BIO_C_DESTROY_BIO_PAIR:
/*
* Affects both BIOs in the pair -- call just once! Or let
* BIO_free(bio1); BIO_free(bio2); do the job.
*/
bio_destroy_pair(bio);
ret = 1;
break;
case BIO_C_GET_WRITE_GUARANTEE:
/*
* How many bytes can the caller feed to the next write without
* having to keep any?
*/
if (b->peer == NULL || b->closed)
ret = 0;
else
ret = (long)b->size - b->len;
break;
case BIO_C_GET_READ_REQUEST:
/*
* If the peer unsuccessfully tried to read, how many bytes were
* requested? (As with BIO_CTRL_PENDING, that number can usually be
* treated as boolean.)
*/
ret = (long)b->request;
break;
case BIO_C_RESET_READ_REQUEST:
/*
* Reset request. (Can be useful after read attempts at the other
* side that are meant to be non-blocking, e.g. when probing SSL_read
* to see if any data is available.)
*/
b->request = 0;
ret = 1;
break;
case BIO_C_SHUTDOWN_WR:
/* similar to shutdown(..., SHUT_WR) */
b->closed = 1;
ret = 1;
break;
case BIO_C_NREAD0:
/* prepare for non-copying read */
ret = (long)bio_nread0(bio, ptr);
break;
case BIO_C_NREAD:
/* non-copying read */
ret = (long)bio_nread(bio, ptr, (size_t)num);
break;
case BIO_C_NWRITE0:
/* prepare for non-copying write */
ret = (long)bio_nwrite0(bio, ptr);
break;
case BIO_C_NWRITE:
/* non-copying write */
ret = (long)bio_nwrite(bio, ptr, (size_t)num);
break;
/* standard CTRL codes follow */
case BIO_CTRL_RESET:
if (b->buf != NULL) {
b->len = 0;
b->offset = 0;
}
ret = 0;
break;
case BIO_CTRL_GET_CLOSE:
ret = bio->shutdown;
break;
case BIO_CTRL_SET_CLOSE:
bio->shutdown = (int)num;
ret = 1;
break;
case BIO_CTRL_PENDING:
if (b->peer != NULL) {
struct bio_bio_st *peer_b = b->peer->ptr;
ret = (long)peer_b->len;
} else
ret = 0;
break;
case BIO_CTRL_WPENDING:
if (b->buf != NULL)
ret = (long)b->len;
else
ret = 0;
break;
case BIO_CTRL_DUP:
/* See BIO_dup_chain for circumstances we have to expect. */
{
BIO *other_bio = ptr;
struct bio_bio_st *other_b;
assert(other_bio != NULL);
other_b = other_bio->ptr;
assert(other_b != NULL);
assert(other_b->buf == NULL); /* other_bio is always fresh */
other_b->size = b->size;
}
ret = 1;
break;
case BIO_CTRL_FLUSH:
ret = 1;
break;
case BIO_CTRL_EOF:
if (b->peer != NULL) {
struct bio_bio_st *peer_b = b->peer->ptr;
if (peer_b->len == 0 && peer_b->closed)
ret = 1;
else
ret = 0;
} else {
ret = 1;
}
break;
default:
ret = 0;
}
return ret;
}
static int bio_puts(BIO *bio, const char *str)
{
return bio_write(bio, str, strlen(str));
}
static int bio_make_pair(BIO *bio1, BIO *bio2)
{
struct bio_bio_st *b1, *b2;
assert(bio1 != NULL);
assert(bio2 != NULL);
b1 = bio1->ptr;
b2 = bio2->ptr;
if (b1->peer != NULL || b2->peer != NULL) {
BIOerr(BIO_F_BIO_MAKE_PAIR, BIO_R_IN_USE);
return 0;
}
if (b1->buf == NULL) {
b1->buf = OPENSSL_malloc(b1->size);
if (b1->buf == NULL) {
BIOerr(BIO_F_BIO_MAKE_PAIR, ERR_R_MALLOC_FAILURE);
return 0;
}
b1->len = 0;
b1->offset = 0;
}
if (b2->buf == NULL) {
b2->buf = OPENSSL_malloc(b2->size);
if (b2->buf == NULL) {
BIOerr(BIO_F_BIO_MAKE_PAIR, ERR_R_MALLOC_FAILURE);
return 0;
}
b2->len = 0;
b2->offset = 0;
}
b1->peer = bio2;
b1->closed = 0;
b1->request = 0;
b2->peer = bio1;
b2->closed = 0;
b2->request = 0;
bio1->init = 1;
bio2->init = 1;
return 1;
}
static void bio_destroy_pair(BIO *bio)
{
struct bio_bio_st *b = bio->ptr;
if (b != NULL) {
BIO *peer_bio = b->peer;
if (peer_bio != NULL) {
struct bio_bio_st *peer_b = peer_bio->ptr;
assert(peer_b != NULL);
assert(peer_b->peer == bio);
peer_b->peer = NULL;
peer_bio->init = 0;
assert(peer_b->buf != NULL);
peer_b->len = 0;
peer_b->offset = 0;
b->peer = NULL;
bio->init = 0;
assert(b->buf != NULL);
b->len = 0;
b->offset = 0;
}
}
}
/* Exported convenience functions */
int BIO_new_bio_pair(BIO **bio1_p, size_t writebuf1,
BIO **bio2_p, size_t writebuf2)
{
BIO *bio1 = NULL, *bio2 = NULL;
long r;
int ret = 0;
bio1 = BIO_new(BIO_s_bio());
if (bio1 == NULL)
goto err;
bio2 = BIO_new(BIO_s_bio());
if (bio2 == NULL)
goto err;
if (writebuf1) {
r = BIO_set_write_buf_size(bio1, writebuf1);
if (!r)
goto err;
}
if (writebuf2) {
r = BIO_set_write_buf_size(bio2, writebuf2);
if (!r)
goto err;
}
r = BIO_make_bio_pair(bio1, bio2);
if (!r)
goto err;
ret = 1;
err:
if (ret == 0) {
BIO_free(bio1);
bio1 = NULL;
BIO_free(bio2);
bio2 = NULL;
}
*bio1_p = bio1;
*bio2_p = bio2;
return ret;
}
size_t BIO_ctrl_get_write_guarantee(BIO *bio)
{
return BIO_ctrl(bio, BIO_C_GET_WRITE_GUARANTEE, 0, NULL);
}
size_t BIO_ctrl_get_read_request(BIO *bio)
{
return BIO_ctrl(bio, BIO_C_GET_READ_REQUEST, 0, NULL);
}
int BIO_ctrl_reset_read_request(BIO *bio)
{
return (BIO_ctrl(bio, BIO_C_RESET_READ_REQUEST, 0, NULL) != 0);
}
/*
* BIO_nread0/nread/nwrite0/nwrite are available only for BIO pairs for now
* (conceivably some other BIOs could allow non-copying reads and writes
* too.)
*/
int BIO_nread0(BIO *bio, char **buf)
{
long ret;
if (!bio->init) {
BIOerr(BIO_F_BIO_NREAD0, BIO_R_UNINITIALIZED);
return -2;
}
ret = BIO_ctrl(bio, BIO_C_NREAD0, 0, buf);
if (ret > INT_MAX)
return INT_MAX;
else
return (int)ret;
}
int BIO_nread(BIO *bio, char **buf, int num)
{
int ret;
if (!bio->init) {
BIOerr(BIO_F_BIO_NREAD, BIO_R_UNINITIALIZED);
return -2;
}
ret = (int)BIO_ctrl(bio, BIO_C_NREAD, num, buf);
if (ret > 0)
bio->num_read += ret;
return ret;
}
int BIO_nwrite0(BIO *bio, char **buf)
{
long ret;
if (!bio->init) {
BIOerr(BIO_F_BIO_NWRITE0, BIO_R_UNINITIALIZED);
return -2;
}
ret = BIO_ctrl(bio, BIO_C_NWRITE0, 0, buf);
if (ret > INT_MAX)
return INT_MAX;
else
return (int)ret;
}
int BIO_nwrite(BIO *bio, char **buf, int num)
{
int ret;
if (!bio->init) {
BIOerr(BIO_F_BIO_NWRITE, BIO_R_UNINITIALIZED);
return -2;
}
ret = BIO_ctrl(bio, BIO_C_NWRITE, num, buf);
if (ret > 0)
bio->num_write += ret;
return ret;
}
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