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/*
*
* Copyright 2018 gRPC authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
#include <grpc/support/port_platform.h>
#include "src/core/tsi/alts/frame_protector/frame_handler.h"
#include <limits.h>
#include <stdint.h>
#include <string.h>
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include "src/core/lib/gpr/useful.h"
/* Use little endian to interpret a string of bytes as uint32_t. */
static uint32_t load_32_le(const unsigned char* buffer) {
return (((uint32_t)buffer[3]) << 24) | (((uint32_t)buffer[2]) << 16) |
(((uint32_t)buffer[1]) << 8) | ((uint32_t)buffer[0]);
}
/* Store uint32_t as a string of little endian bytes. */
static void store_32_le(uint32_t value, unsigned char* buffer) {
buffer[3] = (unsigned char)(value >> 24) & 0xFF;
buffer[2] = (unsigned char)(value >> 16) & 0xFF;
buffer[1] = (unsigned char)(value >> 8) & 0xFF;
buffer[0] = (unsigned char)(value)&0xFF;
}
/* Frame writer implementation. */
alts_frame_writer* alts_create_frame_writer() {
alts_frame_writer* writer =
static_cast<alts_frame_writer*>(gpr_zalloc(sizeof(*writer)));
return writer;
}
bool alts_reset_frame_writer(alts_frame_writer* writer,
const unsigned char* buffer, size_t length) {
if (buffer == nullptr) return false;
size_t max_input_size = SIZE_MAX - kFrameLengthFieldSize;
if (length > max_input_size) {
gpr_log(GPR_ERROR, "length must be at most %zu", max_input_size);
return false;
}
writer->input_buffer = buffer;
writer->input_size = length;
writer->input_bytes_written = 0;
writer->header_bytes_written = 0;
store_32_le(
static_cast<uint32_t>(writer->input_size + kFrameMessageTypeFieldSize),
writer->header_buffer);
store_32_le(kFrameMessageType, writer->header_buffer + kFrameLengthFieldSize);
return true;
}
bool alts_write_frame_bytes(alts_frame_writer* writer, unsigned char* output,
size_t* bytes_size) {
if (bytes_size == nullptr || output == nullptr) return false;
if (alts_is_frame_writer_done(writer)) {
*bytes_size = 0;
return true;
}
size_t bytes_written = 0;
/* Write some header bytes, if needed. */
if (writer->header_bytes_written != sizeof(writer->header_buffer)) {
size_t bytes_to_write =
GPR_MIN(*bytes_size,
sizeof(writer->header_buffer) - writer->header_bytes_written);
memcpy(output, writer->header_buffer + writer->header_bytes_written,
bytes_to_write);
bytes_written += bytes_to_write;
*bytes_size -= bytes_to_write;
writer->header_bytes_written += bytes_to_write;
output += bytes_to_write;
if (writer->header_bytes_written != sizeof(writer->header_buffer)) {
*bytes_size = bytes_written;
return true;
}
}
/* Write some non-header bytes. */
size_t bytes_to_write =
GPR_MIN(writer->input_size - writer->input_bytes_written, *bytes_size);
memcpy(output, writer->input_buffer, bytes_to_write);
writer->input_buffer += bytes_to_write;
bytes_written += bytes_to_write;
writer->input_bytes_written += bytes_to_write;
*bytes_size = bytes_written;
return true;
}
bool alts_is_frame_writer_done(alts_frame_writer* writer) {
return writer->input_buffer == nullptr ||
writer->input_size == writer->input_bytes_written;
}
size_t alts_get_num_writer_bytes_remaining(alts_frame_writer* writer) {
return (sizeof(writer->header_buffer) - writer->header_bytes_written) +
(writer->input_size - writer->input_bytes_written);
}
void alts_destroy_frame_writer(alts_frame_writer* writer) { gpr_free(writer); }
/* Frame reader implementation. */
alts_frame_reader* alts_create_frame_reader() {
alts_frame_reader* reader =
static_cast<alts_frame_reader*>(gpr_zalloc(sizeof(*reader)));
return reader;
}
bool alts_is_frame_reader_done(alts_frame_reader* reader) {
return reader->output_buffer == nullptr ||
(reader->header_bytes_read == sizeof(reader->header_buffer) &&
reader->bytes_remaining == 0);
}
bool alts_has_read_frame_length(alts_frame_reader* reader) {
return sizeof(reader->header_buffer) == reader->header_bytes_read;
}
size_t alts_get_reader_bytes_remaining(alts_frame_reader* reader) {
return alts_has_read_frame_length(reader) ? reader->bytes_remaining : 0;
}
void alts_reset_reader_output_buffer(alts_frame_reader* reader,
unsigned char* buffer) {
reader->output_buffer = buffer;
}
bool alts_reset_frame_reader(alts_frame_reader* reader, unsigned char* buffer) {
if (buffer == nullptr) return false;
reader->output_buffer = buffer;
reader->bytes_remaining = 0;
reader->header_bytes_read = 0;
reader->output_bytes_read = 0;
return true;
}
bool alts_read_frame_bytes(alts_frame_reader* reader,
const unsigned char* bytes, size_t* bytes_size) {
if (bytes_size == nullptr) return false;
if (bytes == nullptr) {
*bytes_size = 0;
return false;
}
if (alts_is_frame_reader_done(reader)) {
*bytes_size = 0;
return true;
}
size_t bytes_processed = 0;
/* Process the header, if needed. */
if (reader->header_bytes_read != sizeof(reader->header_buffer)) {
size_t bytes_to_write = GPR_MIN(
*bytes_size, sizeof(reader->header_buffer) - reader->header_bytes_read);
memcpy(reader->header_buffer + reader->header_bytes_read, bytes,
bytes_to_write);
reader->header_bytes_read += bytes_to_write;
bytes_processed += bytes_to_write;
bytes += bytes_to_write;
*bytes_size -= bytes_to_write;
if (reader->header_bytes_read != sizeof(reader->header_buffer)) {
*bytes_size = bytes_processed;
return true;
}
size_t frame_length = load_32_le(reader->header_buffer);
if (frame_length < kFrameMessageTypeFieldSize ||
frame_length > kFrameMaxSize) {
gpr_log(GPR_ERROR,
"Bad frame length (should be at least %zu, and at most %zu)",
kFrameMessageTypeFieldSize, kFrameMaxSize);
*bytes_size = 0;
return false;
}
size_t message_type =
load_32_le(reader->header_buffer + kFrameLengthFieldSize);
if (message_type != kFrameMessageType) {
gpr_log(GPR_ERROR, "Unsupported message type %zu (should be %zu)",
message_type, kFrameMessageType);
*bytes_size = 0;
return false;
}
reader->bytes_remaining = frame_length - kFrameMessageTypeFieldSize;
}
/* Process the non-header bytes. */
size_t bytes_to_write = GPR_MIN(*bytes_size, reader->bytes_remaining);
memcpy(reader->output_buffer, bytes, bytes_to_write);
reader->output_buffer += bytes_to_write;
bytes_processed += bytes_to_write;
reader->bytes_remaining -= bytes_to_write;
reader->output_bytes_read += bytes_to_write;
*bytes_size = bytes_processed;
return true;
}
size_t alts_get_output_bytes_read(alts_frame_reader* reader) {
return reader->output_bytes_read;
}
unsigned char* alts_get_output_buffer(alts_frame_reader* reader) {
return reader->output_buffer;
}
void alts_destroy_frame_reader(alts_frame_reader* reader) { gpr_free(reader); }
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