ref: 8bc69a872883224675a55db51ac8f60ab5ed9e5a
dir: /third_party/boringssl/src/ssl/ssl_buffer.cc/
/* 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"
BSSL_NAMESPACE_BEGIN
// 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");
void SSLBuffer::Clear() {
if (buf_allocated_) {
free(buf_); // Allocated with malloc().
}
buf_ = nullptr;
buf_allocated_ = false;
offset_ = 0;
size_ = 0;
cap_ = 0;
}
bool SSLBuffer::EnsureCap(size_t header_len, size_t new_cap) {
if (new_cap > 0xffff) {
OPENSSL_PUT_ERROR(SSL, ERR_R_INTERNAL_ERROR);
return false;
}
if (cap_ >= new_cap) {
return true;
}
uint8_t *new_buf;
bool new_buf_allocated;
size_t new_offset;
if (new_cap <= sizeof(inline_buf_)) {
// This function is called twice per TLS record, first for the five-byte
// header. To avoid allocating twice, use an inline buffer for short inputs.
new_buf = inline_buf_;
new_buf_allocated = false;
new_offset = 0;
} else {
// Add up to |SSL3_ALIGN_PAYLOAD| - 1 bytes of slack for alignment.
//
// Since this buffer gets allocated quite frequently and doesn't contain any
// sensitive data, we allocate with malloc rather than |OPENSSL_malloc| and
// avoid zeroing on free.
new_buf = (uint8_t *)malloc(new_cap + SSL3_ALIGN_PAYLOAD - 1);
if (new_buf == NULL) {
OPENSSL_PUT_ERROR(SSL, ERR_R_MALLOC_FAILURE);
return false;
}
new_buf_allocated = true;
// Offset the buffer such that the record body is aligned.
new_offset =
(0 - header_len - (uintptr_t)new_buf) & (SSL3_ALIGN_PAYLOAD - 1);
}
// Note if the both old and new buffer are inline, the source and destination
// may alias.
OPENSSL_memmove(new_buf + new_offset, buf_ + offset_, size_);
if (buf_allocated_) {
free(buf_); // Allocated with malloc().
}
buf_ = new_buf;
buf_allocated_ = new_buf_allocated;
offset_ = new_offset;
cap_ = new_cap;
return true;
}
void SSLBuffer::DidWrite(size_t new_size) {
if (new_size > cap() - size()) {
abort();
}
size_ += new_size;
}
void SSLBuffer::Consume(size_t len) {
if (len > size_) {
abort();
}
offset_ += (uint16_t)len;
size_ -= (uint16_t)len;
cap_ -= (uint16_t)len;
}
void SSLBuffer::DiscardConsumed() {
if (size_ == 0) {
Clear();
}
}
static int dtls_read_buffer_next_packet(SSL *ssl) {
SSLBuffer *buf = &ssl->s3->read_buffer;
if (!buf->empty()) {
// 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.get(), buf->data(), static_cast<int>(buf->cap()));
if (ret <= 0) {
ssl->s3->rwstate = SSL_ERROR_WANT_READ;
return ret;
}
buf->DidWrite(static_cast<size_t>(ret));
return 1;
}
static int tls_read_buffer_extend_to(SSL *ssl, size_t len) {
SSLBuffer *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->size() < len) {
// The amount of data to read is bounded by |buf->cap|, which must fit in an
// int.
int ret = BIO_read(ssl->rbio.get(), buf->data() + buf->size(),
static_cast<int>(len - buf->size()));
if (ret <= 0) {
ssl->s3->rwstate = SSL_ERROR_WANT_READ;
return ret;
}
buf->DidWrite(static_cast<size_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->s3->read_buffer.DiscardConsumed();
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 (!ssl->s3->read_buffer.EnsureCap(ssl_record_prefix_len(ssl), len)) {
return -1;
}
if (ssl->rbio == nullptr) {
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->s3->read_buffer.DiscardConsumed();
}
return ret;
}
int ssl_handle_open_record(SSL *ssl, bool *out_retry, ssl_open_record_t ret,
size_t consumed, uint8_t alert) {
*out_retry = false;
if (ret != ssl_open_record_partial) {
ssl->s3->read_buffer.Consume(consumed);
}
if (ret != ssl_open_record_success) {
// Nothing was returned to the caller, so discard anything marked consumed.
ssl->s3->read_buffer.DiscardConsumed();
}
switch (ret) {
case ssl_open_record_success:
return 1;
case ssl_open_record_partial: {
int read_ret = ssl_read_buffer_extend_to(ssl, consumed);
if (read_ret <= 0) {
return read_ret;
}
*out_retry = true;
return 1;
}
case ssl_open_record_discard:
*out_retry = true;
return 1;
case ssl_open_record_close_notify:
return 0;
case ssl_open_record_error:
if (alert != 0) {
ssl_send_alert(ssl, SSL3_AL_FATAL, alert);
}
return -1;
}
assert(0);
return -1;
}
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");
static int tls_write_buffer_flush(SSL *ssl) {
SSLBuffer *buf = &ssl->s3->write_buffer;
while (!buf->empty()) {
int ret = BIO_write(ssl->wbio.get(), buf->data(), buf->size());
if (ret <= 0) {
ssl->s3->rwstate = SSL_ERROR_WANT_WRITE;
return ret;
}
buf->Consume(static_cast<size_t>(ret));
}
buf->Clear();
return 1;
}
static int dtls_write_buffer_flush(SSL *ssl) {
SSLBuffer *buf = &ssl->s3->write_buffer;
if (buf->empty()) {
return 1;
}
int ret = BIO_write(ssl->wbio.get(), buf->data(), buf->size());
if (ret <= 0) {
ssl->s3->rwstate = SSL_ERROR_WANT_WRITE;
// 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.
buf->Clear();
return ret;
}
buf->Clear();
return 1;
}
int ssl_write_buffer_flush(SSL *ssl) {
if (ssl->wbio == nullptr) {
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);
}
}
BSSL_NAMESPACE_END