blob: 7f11b6f1a3aaded5a0fb4e71e75307677751e01a [file] [log] [blame]
/* Copyright (c) 2015, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include <openssl/ssl.h>
#include <assert.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/bio.h>
#include <openssl/err.h>
#include <openssl/mem.h>
#include "../crypto/internal.h"
#include "internal.h"
namespace bssl {
/* BIO uses int instead of size_t. No lengths will exceed uint16_t, so this will
* not overflow. */
static_assert(0xffff <= INT_MAX, "uint16_t does not fit in int");
static_assert((SSL3_ALIGN_PAYLOAD & (SSL3_ALIGN_PAYLOAD - 1)) == 0,
"SSL3_ALIGN_PAYLOAD must be a power of 2");
/* ensure_buffer ensures |buf| has capacity at least |cap|, aligned such that
* data written after |header_len| is aligned to a |SSL3_ALIGN_PAYLOAD|-byte
* boundary. It returns one on success and zero on error. */
static int ensure_buffer(SSL3_BUFFER *buf, size_t header_len, size_t cap) {
if (cap > 0xffff) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return 0;
}
if (buf->cap >= cap) {
return 1;
}
/* Add up to |SSL3_ALIGN_PAYLOAD| - 1 bytes of slack for alignment. */
uint8_t *new_buf = (uint8_t *)OPENSSL_malloc(cap + SSL3_ALIGN_PAYLOAD - 1);
if (new_buf == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
return 0;
}
/* Offset the buffer such that the record body is aligned. */
size_t new_offset =
(0 - header_len - (uintptr_t)new_buf) & (SSL3_ALIGN_PAYLOAD - 1);
if (buf->buf != NULL) {
OPENSSL_memcpy(new_buf + new_offset, buf->buf + buf->offset, buf->len);
OPENSSL_free(buf->buf);
}
buf->buf = new_buf;
buf->offset = new_offset;
buf->cap = cap;
return 1;
}
static void consume_buffer(SSL3_BUFFER *buf, size_t len) {
if (len > buf->len) {
abort();
}
buf->offset += (uint16_t)len;
buf->len -= (uint16_t)len;
buf->cap -= (uint16_t)len;
}
static void clear_buffer(SSL3_BUFFER *buf) {
OPENSSL_free(buf->buf);
OPENSSL_memset(buf, 0, sizeof(SSL3_BUFFER));
}
uint8_t *ssl_read_buffer(SSL *ssl) {
return ssl->s3->read_buffer.buf + ssl->s3->read_buffer.offset;
}
size_t ssl_read_buffer_len(const SSL *ssl) {
return ssl->s3->read_buffer.len;
}
static int dtls_read_buffer_next_packet(SSL *ssl) {
SSL3_BUFFER *buf = &ssl->s3->read_buffer;
if (buf->len > 0) {
/* It is an error to call |dtls_read_buffer_extend| when the read buffer is
* not empty. */
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return -1;
}
/* Read a single packet from |ssl->rbio|. |buf->cap| must fit in an int. */
int ret = BIO_read(ssl->rbio, buf->buf + buf->offset, (int)buf->cap);
if (ret <= 0) {
ssl->rwstate = SSL_READING;
return ret;
}
/* |BIO_read| was bound by |buf->cap|, so this cannot overflow. */
buf->len = (uint16_t)ret;
return 1;
}
static int tls_read_buffer_extend_to(SSL *ssl, size_t len) {
SSL3_BUFFER *buf = &ssl->s3->read_buffer;
if (len > buf->cap) {
OPENSSL_PUT_ERROR(SSL, SSL_R_BUFFER_TOO_SMALL);
return -1;
}
/* Read until the target length is reached. */
while (buf->len < len) {
/* The amount of data to read is bounded by |buf->cap|, which must fit in an
* int. */
int ret = BIO_read(ssl->rbio, buf->buf + buf->offset + buf->len,
(int)(len - buf->len));
if (ret <= 0) {
ssl->rwstate = SSL_READING;
return ret;
}
/* |BIO_read| was bound by |buf->cap - buf->len|, so this cannot
* overflow. */
buf->len += (uint16_t)ret;
}
return 1;
}
int ssl_read_buffer_extend_to(SSL *ssl, size_t len) {
/* |ssl_read_buffer_extend_to| implicitly discards any consumed data. */
ssl_read_buffer_discard(ssl);
if (SSL_is_dtls(ssl)) {
static_assert(
DTLS1_RT_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH <= 0xffff,
"DTLS read buffer is too large");
/* The |len| parameter is ignored in DTLS. */
len = DTLS1_RT_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
}
if (!ensure_buffer(&ssl->s3->read_buffer, ssl_record_prefix_len(ssl), len)) {
return -1;
}
if (ssl->rbio == NULL) {
OPENSSL_PUT_ERROR(SSL, SSL_R_BIO_NOT_SET);
return -1;
}
int ret;
if (SSL_is_dtls(ssl)) {
/* |len| is ignored for a datagram transport. */
ret = dtls_read_buffer_next_packet(ssl);
} else {
ret = tls_read_buffer_extend_to(ssl, len);
}
if (ret <= 0) {
/* If the buffer was empty originally and remained empty after attempting to
* extend it, release the buffer until the next attempt. */
ssl_read_buffer_discard(ssl);
}
return ret;
}
void ssl_read_buffer_consume(SSL *ssl, size_t len) {
SSL3_BUFFER *buf = &ssl->s3->read_buffer;
consume_buffer(buf, len);
/* The TLS stack never reads beyond the current record, so there will never be
* unconsumed data. If read-ahead is ever reimplemented,
* |ssl_read_buffer_discard| will require a |memcpy| to shift the excess back
* to the front of the buffer, to ensure there is enough space for the next
* record. */
assert(SSL_is_dtls(ssl) || len == 0 || buf->len == 0);
}
void ssl_read_buffer_discard(SSL *ssl) {
if (ssl->s3->read_buffer.len == 0) {
ssl_read_buffer_clear(ssl);
}
}
void ssl_read_buffer_clear(SSL *ssl) {
clear_buffer(&ssl->s3->read_buffer);
}
int ssl_write_buffer_is_pending(const SSL *ssl) {
return ssl->s3->write_buffer.len > 0;
}
static_assert(SSL3_RT_HEADER_LENGTH * 2 +
SSL3_RT_SEND_MAX_ENCRYPTED_OVERHEAD * 2 +
SSL3_RT_MAX_PLAIN_LENGTH <=
0xffff,
"maximum TLS write buffer is too large");
static_assert(DTLS1_RT_HEADER_LENGTH + SSL3_RT_SEND_MAX_ENCRYPTED_OVERHEAD +
SSL3_RT_MAX_PLAIN_LENGTH <=
0xffff,
"maximum DTLS write buffer is too large");
int ssl_write_buffer_init(SSL *ssl, uint8_t **out_ptr, size_t max_len) {
SSL3_BUFFER *buf = &ssl->s3->write_buffer;
if (buf->buf != NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return 0;
}
if (!ensure_buffer(buf, ssl_seal_align_prefix_len(ssl), max_len)) {
return 0;
}
*out_ptr = buf->buf + buf->offset;
return 1;
}
void ssl_write_buffer_set_len(SSL *ssl, size_t len) {
SSL3_BUFFER *buf = &ssl->s3->write_buffer;
if (len > buf->cap) {
abort();
}
buf->len = len;
}
static int tls_write_buffer_flush(SSL *ssl) {
SSL3_BUFFER *buf = &ssl->s3->write_buffer;
while (buf->len > 0) {
int ret = BIO_write(ssl->wbio, buf->buf + buf->offset, buf->len);
if (ret <= 0) {
ssl->rwstate = SSL_WRITING;
return ret;
}
consume_buffer(buf, (size_t)ret);
}
ssl_write_buffer_clear(ssl);
return 1;
}
static int dtls_write_buffer_flush(SSL *ssl) {
SSL3_BUFFER *buf = &ssl->s3->write_buffer;
if (buf->len == 0) {
return 1;
}
int ret = BIO_write(ssl->wbio, buf->buf + buf->offset, buf->len);
if (ret <= 0) {
ssl->rwstate = SSL_WRITING;
/* If the write failed, drop the write buffer anyway. Datagram transports
* can't write half a packet, so the caller is expected to retry from the
* top. */
ssl_write_buffer_clear(ssl);
return ret;
}
ssl_write_buffer_clear(ssl);
return 1;
}
int ssl_write_buffer_flush(SSL *ssl) {
if (ssl->wbio == NULL) {
OPENSSL_PUT_ERROR(SSL, SSL_R_BIO_NOT_SET);
return -1;
}
if (SSL_is_dtls(ssl)) {
return dtls_write_buffer_flush(ssl);
} else {
return tls_write_buffer_flush(ssl);
}
}
void ssl_write_buffer_clear(SSL *ssl) {
clear_buffer(&ssl->s3->write_buffer);
}
} // namespace bssl