| /* |
| * Copyright 2014 The Android Open Source Project |
| * |
| * 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 <keymaster/serializable.h> |
| |
| #include <assert.h> |
| |
| #include <keymaster/new.h> |
| |
| #include <keymaster/android_keymaster_utils.h> |
| |
| namespace keymaster { |
| |
| namespace { |
| |
| /* Performs an overflow-checked bounds check */ |
| bool buffer_bound_check(const uint8_t* buf, const uint8_t* end, size_t len) { |
| uintptr_t buf_next; |
| bool overflow_occurred = __builtin_add_overflow(__pval(buf), len, &buf_next); |
| return (!overflow_occurred) && (buf_next <= __pval(end)); |
| } |
| |
| } |
| |
| uint8_t* append_to_buf(uint8_t* buf, const uint8_t* end, const void* data, size_t data_len) { |
| if (buffer_bound_check(buf, end, data_len)) { |
| memcpy(buf, data, data_len); |
| return buf + data_len; |
| } else { |
| return buf; |
| } |
| } |
| |
| bool copy_from_buf(const uint8_t** buf_ptr, const uint8_t* end, void* dest, size_t size) { |
| if (buffer_bound_check(*buf_ptr, end, size)) { |
| memcpy(dest, *buf_ptr, size); |
| *buf_ptr += size; |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| bool copy_size_and_data_from_buf(const uint8_t** buf_ptr, const uint8_t* end, size_t* size, |
| UniquePtr<uint8_t[]>* dest) { |
| if (!copy_uint32_from_buf(buf_ptr, end, size)) |
| return false; |
| |
| if (*size == 0) { |
| dest->reset(); |
| return true; |
| } |
| |
| if (buffer_bound_check(*buf_ptr, end, *size)) { |
| dest->reset(new (std::nothrow) uint8_t[*size]); |
| if (!dest->get()) { |
| return false; |
| } |
| return copy_from_buf(buf_ptr, end, dest->get(), *size); |
| } else { |
| return false; |
| } |
| } |
| |
| bool Buffer::reserve(size_t size) { |
| if (available_write() < size) { |
| size_t new_size = buffer_size_ + size - available_write(); |
| uint8_t* new_buffer = new (std::nothrow) uint8_t[new_size]; |
| if (!new_buffer) |
| return false; |
| memcpy(new_buffer, buffer_.get() + read_position_, available_read()); |
| memset_s(buffer_.get(), 0, buffer_size_); |
| buffer_.reset(new_buffer); |
| buffer_size_ = new_size; |
| write_position_ -= read_position_; |
| read_position_ = 0; |
| } |
| return true; |
| } |
| |
| bool Buffer::Reinitialize(size_t size) { |
| Clear(); |
| buffer_.reset(new (std::nothrow) uint8_t[size]); |
| if (!buffer_.get()) |
| return false; |
| buffer_size_ = size; |
| read_position_ = 0; |
| write_position_ = 0; |
| return true; |
| } |
| |
| bool Buffer::Reinitialize(const void* data, size_t data_len) { |
| Clear(); |
| if (__pval(data) + data_len < __pval(data)) // Pointer wrap check |
| return false; |
| buffer_.reset(new (std::nothrow) uint8_t[data_len]); |
| if (!buffer_.get()) |
| return false; |
| buffer_size_ = data_len; |
| memcpy(buffer_.get(), data, data_len); |
| read_position_ = 0; |
| write_position_ = buffer_size_; |
| return true; |
| } |
| |
| size_t Buffer::available_write() const { |
| assert(buffer_size_ >= write_position_); |
| return buffer_size_ - write_position_; |
| } |
| |
| size_t Buffer::available_read() const { |
| assert(buffer_size_ >= write_position_); |
| assert(write_position_ >= read_position_); |
| return write_position_ - read_position_; |
| } |
| |
| bool Buffer::write(const uint8_t* src, size_t write_length) { |
| if (available_write() < write_length) |
| return false; |
| memcpy(buffer_.get() + write_position_, src, write_length); |
| write_position_ += write_length; |
| return true; |
| } |
| |
| bool Buffer::read(uint8_t* dest, size_t read_length) { |
| if (available_read() < read_length) |
| return false; |
| memcpy(dest, buffer_.get() + read_position_, read_length); |
| read_position_ += read_length; |
| return true; |
| } |
| |
| size_t Buffer::SerializedSize() const { |
| return sizeof(uint32_t) + available_read(); |
| } |
| |
| uint8_t* Buffer::Serialize(uint8_t* buf, const uint8_t* end) const { |
| return append_size_and_data_to_buf(buf, end, peek_read(), available_read()); |
| } |
| |
| bool Buffer::Deserialize(const uint8_t** buf_ptr, const uint8_t* end) { |
| Clear(); |
| if (!copy_size_and_data_from_buf(buf_ptr, end, &buffer_size_, &buffer_)) { |
| buffer_.reset(); |
| buffer_size_ = 0; |
| return false; |
| } |
| write_position_ = buffer_size_; |
| return true; |
| } |
| |
| void Buffer::Clear() { |
| memset_s(buffer_.get(), 0, buffer_size_); |
| buffer_.reset(); |
| read_position_ = 0; |
| write_position_ = 0; |
| buffer_size_ = 0; |
| } |
| |
| } // namespace keymaster |