| // |
| // Copyright (C) 2018 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 "update_engine/payload_consumer/verity_writer_android.h" |
| |
| #include <fcntl.h> |
| |
| #include <algorithm> |
| #include <memory> |
| #include <utility> |
| |
| #include <base/logging.h> |
| #include <base/posix/eintr_wrapper.h> |
| #include <fec/ecc.h> |
| extern "C" { |
| #include <fec.h> |
| } |
| |
| #include "update_engine/common/utils.h" |
| #include "update_engine/payload_consumer/cached_file_descriptor.h" |
| #include "update_engine/payload_consumer/file_descriptor.h" |
| |
| namespace chromeos_update_engine { |
| |
| bool IncrementalEncodeFEC::Init(const uint64_t _data_offset, |
| const uint64_t _data_size, |
| const uint64_t _fec_offset, |
| const uint64_t _fec_size, |
| const uint64_t _fec_roots, |
| const uint64_t _block_size, |
| const bool _verify_mode) { |
| current_step_ = EncodeFECStep::kInitFDStep; |
| data_offset_ = _data_offset; |
| data_size_ = _data_size; |
| fec_offset_ = _fec_offset; |
| fec_size_ = _fec_size; |
| fec_roots_ = _fec_roots; |
| block_size_ = _block_size; |
| verify_mode_ = _verify_mode; |
| current_round_ = 0; |
| // This is the N in RS(M, N), which is the number of bytes for each rs block. |
| rs_n_ = FEC_RSM - fec_roots_; |
| rs_char_.reset(init_rs_char(FEC_PARAMS(fec_roots_))); |
| rs_blocks_.resize(block_size_ * rs_n_); |
| buffer_.resize(block_size_, 0); |
| fec_.resize(block_size_ * fec_roots_); |
| fec_read_.resize(fec_.size()); |
| TEST_AND_RETURN_FALSE(data_size_ % block_size_ == 0); |
| TEST_AND_RETURN_FALSE(fec_roots_ >= 0 && fec_roots_ < FEC_RSM); |
| |
| num_rounds_ = utils::DivRoundUp(data_size_ / block_size_, rs_n_); |
| TEST_AND_RETURN_FALSE(num_rounds_ * fec_roots_ * block_size_ == fec_size_); |
| TEST_AND_RETURN_FALSE(rs_char_ != nullptr); |
| return true; |
| } |
| |
| bool IncrementalEncodeFEC::Compute(FileDescriptor* _read_fd, |
| FileDescriptor* _write_fd) { |
| if (current_step_ == EncodeFECStep::kInitFDStep) { |
| read_fd_ = _read_fd; |
| write_fd_ = _write_fd; |
| cache_fd_.SetFD(write_fd_); |
| write_fd_ = &cache_fd_; |
| } else if (current_step_ == EncodeFECStep::kEncodeRoundStep) { |
| // Encodes |block_size| number of rs blocks each round so that we can read |
| // one block each time instead of 1 byte to increase random read |
| // performance. This uses about 1 MiB memory for 4K block size. |
| for (size_t j = 0; j < rs_n_; j++) { |
| uint64_t offset = fec_ecc_interleave( |
| current_round_ * rs_n_ * block_size_ + j, rs_n_, num_rounds_); |
| // Don't read past |data_size|, treat them as 0. |
| if (offset >= data_size_) { |
| std::fill(buffer_.begin(), buffer_.end(), 0); |
| } else { |
| ssize_t bytes_read = 0; |
| TEST_AND_RETURN_FALSE(utils::PReadAll(read_fd_, |
| buffer_.data(), |
| buffer_.size(), |
| data_offset_ + offset, |
| &bytes_read)); |
| TEST_AND_RETURN_FALSE(bytes_read >= 0); |
| TEST_AND_RETURN_FALSE(static_cast<size_t>(bytes_read) == |
| buffer_.size()); |
| } |
| for (size_t k = 0; k < buffer_.size(); k++) { |
| rs_blocks_[k * rs_n_ + j] = buffer_[k]; |
| } |
| } |
| for (size_t j = 0; j < block_size_; j++) { |
| // Encode [j * rs_n_ : (j + 1) * rs_n_) in |rs_blocks| and write |
| // |fec_roots| number of parity bytes to |j * fec_roots| in |fec|. |
| encode_rs_char(rs_char_.get(), |
| rs_blocks_.data() + j * rs_n_, |
| fec_.data() + j * fec_roots_); |
| } |
| |
| if (verify_mode_) { |
| ssize_t bytes_read = 0; |
| TEST_AND_RETURN_FALSE(utils::PReadAll(read_fd_, |
| fec_read_.data(), |
| fec_read_.size(), |
| fec_offset_, |
| &bytes_read)); |
| TEST_AND_RETURN_FALSE(bytes_read >= 0); |
| TEST_AND_RETURN_FALSE(static_cast<size_t>(bytes_read) == |
| fec_read_.size()); |
| TEST_AND_RETURN_FALSE(fec_ == fec_read_); |
| } else { |
| CHECK(write_fd_); |
| write_fd_->Seek(fec_offset_, SEEK_SET); |
| if (!utils::WriteAll(write_fd_, fec_.data(), fec_.size())) { |
| PLOG(ERROR) << "EncodeFEC write() failed"; |
| return false; |
| } |
| } |
| fec_offset_ += fec_.size(); |
| current_round_++; |
| } else if (current_step_ == EncodeFECStep::kWriteStep) { |
| write_fd_->Flush(); |
| } |
| UpdateState(); |
| return true; |
| } |
| // update the current state of EncodeFEC. Can be changed to have smaller steps |
| void IncrementalEncodeFEC::UpdateState() { |
| if (current_step_ == EncodeFECStep::kInitFDStep) { |
| current_step_ = EncodeFECStep::kEncodeRoundStep; |
| } else if (current_step_ == EncodeFECStep::kEncodeRoundStep && |
| current_round_ == num_rounds_) { |
| current_step_ = EncodeFECStep::kWriteStep; |
| } else if (current_step_ == EncodeFECStep::kWriteStep) { |
| current_step_ = EncodeFECStep::kComplete; |
| } |
| } |
| |
| bool IncrementalEncodeFEC::Finished() const { |
| return current_step_ == EncodeFECStep::kComplete; |
| } |
| |
| double IncrementalEncodeFEC::ReportProgress() const { |
| if (num_rounds_ == 0) { |
| return 1.0; |
| } |
| return static_cast<double>(current_round_) / num_rounds_; |
| } |
| |
| namespace verity_writer { |
| std::unique_ptr<VerityWriterInterface> CreateVerityWriter() { |
| return std::make_unique<VerityWriterAndroid>(); |
| } |
| } // namespace verity_writer |
| |
| bool VerityWriterAndroid::Init(const InstallPlan::Partition& partition) { |
| partition_ = &partition; |
| LOG(INFO) << "Initializing Incremental EncodeFEC"; |
| TEST_AND_RETURN_FALSE(encodeFEC_.Init(partition_->fec_data_offset, |
| partition_->fec_data_size, |
| partition_->fec_offset, |
| partition_->fec_size, |
| partition_->fec_roots, |
| partition_->block_size, |
| false /* verify_mode */)); |
| hash_tree_written_ = false; |
| if (partition_->hash_tree_size != 0) { |
| auto hash_function = |
| HashTreeBuilder::HashFunction(partition_->hash_tree_algorithm); |
| if (hash_function == nullptr) { |
| LOG(ERROR) << "Verity hash algorithm not supported: " |
| << partition_->hash_tree_algorithm; |
| return false; |
| } |
| hash_tree_builder_ = std::make_unique<HashTreeBuilder>( |
| partition_->block_size, hash_function); |
| TEST_AND_RETURN_FALSE(hash_tree_builder_->Initialize( |
| partition_->hash_tree_data_size, partition_->hash_tree_salt)); |
| if (hash_tree_builder_->CalculateSize(partition_->hash_tree_data_size) != |
| partition_->hash_tree_size) { |
| LOG(ERROR) << "Verity hash tree size does not match, stored: " |
| << partition_->hash_tree_size << ", calculated: " |
| << hash_tree_builder_->CalculateSize( |
| partition_->hash_tree_data_size); |
| return false; |
| } |
| } |
| total_offset_ = 0; |
| return true; |
| } |
| |
| bool VerityWriterAndroid::Update(const uint64_t offset, |
| const uint8_t* buffer, |
| size_t size) { |
| if (offset != total_offset_) { |
| LOG(ERROR) << "Sequential read expected, expected to read at: " |
| << total_offset_ << " actual read occurs at: " << offset; |
| return false; |
| } |
| if (partition_->hash_tree_size != 0) { |
| const uint64_t hash_tree_data_end = |
| partition_->hash_tree_data_offset + partition_->hash_tree_data_size; |
| const uint64_t start_offset = |
| std::max(offset, partition_->hash_tree_data_offset); |
| if (offset + size > hash_tree_data_end) { |
| LOG(WARNING) |
| << "Reading past hash_tree_data_end, something is probably " |
| "wrong, might cause incorrect hash of partitions. offset: " |
| << offset << " size: " << size |
| << " hash_tree_data_end: " << hash_tree_data_end; |
| } |
| const uint64_t end_offset = std::min(offset + size, hash_tree_data_end); |
| if (start_offset < end_offset) { |
| TEST_AND_RETURN_FALSE(hash_tree_builder_->Update( |
| buffer + start_offset - offset, end_offset - start_offset)); |
| |
| if (end_offset == hash_tree_data_end) { |
| LOG(INFO) |
| << "Read everything before hash tree. Ready to write hash tree."; |
| } |
| } |
| } |
| total_offset_ += size; |
| |
| return true; |
| } |
| bool VerityWriterAndroid::Finalize(FileDescriptor* read_fd, |
| FileDescriptor* write_fd) { |
| const auto hash_tree_data_end = |
| partition_->hash_tree_data_offset + partition_->hash_tree_data_size; |
| if (total_offset_ < hash_tree_data_end) { |
| LOG(ERROR) << "Read up to " << total_offset_ |
| << " when we are expecting to read everything " |
| "before " |
| << hash_tree_data_end; |
| return false; |
| } |
| // All hash tree data blocks has been hashed, write hash tree to disk. |
| LOG(INFO) << "Writing verity hash tree to " |
| << partition_->readonly_target_path; |
| if (hash_tree_builder_) { |
| TEST_AND_RETURN_FALSE(hash_tree_builder_->BuildHashTree()); |
| TEST_AND_RETURN_FALSE_ERRNO( |
| write_fd->Seek(partition_->hash_tree_offset, SEEK_SET)); |
| auto success = |
| hash_tree_builder_->WriteHashTree([write_fd](auto data, auto size) { |
| return utils::WriteAll(write_fd, data, size); |
| }); |
| // hashtree builder already prints error messages. |
| TEST_AND_RETURN_FALSE(success); |
| hash_tree_builder_.reset(); |
| } |
| if (partition_->fec_size != 0) { |
| LOG(INFO) << "Writing verity FEC to " << partition_->readonly_target_path; |
| TEST_AND_RETURN_FALSE(EncodeFEC(read_fd, |
| write_fd, |
| partition_->fec_data_offset, |
| partition_->fec_data_size, |
| partition_->fec_offset, |
| partition_->fec_size, |
| partition_->fec_roots, |
| partition_->block_size, |
| false /* verify_mode */)); |
| } |
| return true; |
| } |
| |
| bool VerityWriterAndroid::IncrementalFinalize(FileDescriptor* read_fd, |
| FileDescriptor* write_fd) { |
| if (!hash_tree_written_) { |
| LOG(INFO) << "Completing prework in Finalize"; |
| const auto hash_tree_data_end = |
| partition_->hash_tree_data_offset + partition_->hash_tree_data_size; |
| if (total_offset_ < hash_tree_data_end) { |
| LOG(ERROR) << "Read up to " << total_offset_ |
| << " when we are expecting to read everything " |
| "before " |
| << hash_tree_data_end; |
| return false; |
| } |
| // All hash tree data blocks has been hashed, write hash tree to disk. |
| LOG(INFO) << "Writing verity hash tree to " |
| << partition_->readonly_target_path; |
| if (hash_tree_builder_) { |
| TEST_AND_RETURN_FALSE(hash_tree_builder_->BuildHashTree()); |
| TEST_AND_RETURN_FALSE_ERRNO( |
| write_fd->Seek(partition_->hash_tree_offset, SEEK_SET)); |
| auto success = |
| hash_tree_builder_->WriteHashTree([write_fd](auto data, auto size) { |
| return utils::WriteAll(write_fd, data, size); |
| }); |
| // hashtree builder already prints error messages. |
| TEST_AND_RETURN_FALSE(success); |
| hash_tree_builder_.reset(); |
| } |
| hash_tree_written_ = true; |
| if (partition_->fec_size != 0) { |
| LOG(INFO) << "Writing verity FEC to " << partition_->readonly_target_path; |
| } |
| } |
| if (partition_->fec_size != 0) { |
| TEST_AND_RETURN_FALSE(encodeFEC_.Compute(read_fd, write_fd)); |
| } |
| return true; |
| } |
| bool VerityWriterAndroid::FECFinished() const { |
| if ((encodeFEC_.Finished() || partition_->fec_size == 0) && |
| hash_tree_written_) { |
| return true; |
| } |
| return false; |
| } |
| |
| double VerityWriterAndroid::GetProgress() { |
| return encodeFEC_.ReportProgress(); |
| } |
| |
| bool VerityWriterAndroid::EncodeFEC(FileDescriptor* read_fd, |
| FileDescriptor* write_fd, |
| uint64_t data_offset, |
| uint64_t data_size, |
| uint64_t fec_offset, |
| uint64_t fec_size, |
| uint32_t fec_roots, |
| uint32_t block_size, |
| bool verify_mode) { |
| TEST_AND_RETURN_FALSE(data_size % block_size == 0); |
| TEST_AND_RETURN_FALSE(fec_roots >= 0 && fec_roots < FEC_RSM); |
| // This is the N in RS(M, N), which is the number of bytes for each rs |
| // block. |
| size_t rs_n = FEC_RSM - fec_roots; |
| uint64_t rounds = utils::DivRoundUp(data_size / block_size, rs_n); |
| TEST_AND_RETURN_FALSE(rounds * fec_roots * block_size == fec_size); |
| |
| std::unique_ptr<void, decltype(&free_rs_char)> rs_char( |
| init_rs_char(FEC_PARAMS(fec_roots)), &free_rs_char); |
| TEST_AND_RETURN_FALSE(rs_char != nullptr); |
| // Cache at most 1MB of fec data, in VABC, we need to re-open fd if we |
| // perform a read() operation after write(). So reduce the number of writes |
| // can save unnecessary re-opens. |
| UnownedCachedFileDescriptor cache_fd(write_fd, 1 * (1 << 20)); |
| write_fd = &cache_fd; |
| |
| for (size_t i = 0; i < rounds; i++) { |
| // Encodes |block_size| number of rs blocks each round so that we can read |
| // one block each time instead of 1 byte to increase random read |
| // performance. This uses about 1 MiB memory for 4K block size. |
| brillo::Blob rs_blocks(block_size * rs_n); |
| for (size_t j = 0; j < rs_n; j++) { |
| brillo::Blob buffer(block_size, 0); |
| uint64_t offset = |
| fec_ecc_interleave(i * rs_n * block_size + j, rs_n, rounds); |
| // Don't read past |data_size|, treat them as 0. |
| if (offset < data_size) { |
| ssize_t bytes_read = 0; |
| TEST_AND_RETURN_FALSE(utils::PReadAll(read_fd, |
| buffer.data(), |
| buffer.size(), |
| data_offset + offset, |
| &bytes_read)); |
| TEST_AND_RETURN_FALSE(bytes_read >= 0); |
| TEST_AND_RETURN_FALSE(static_cast<size_t>(bytes_read) == buffer.size()); |
| } |
| for (size_t k = 0; k < buffer.size(); k++) { |
| rs_blocks[k * rs_n + j] = buffer[k]; |
| } |
| } |
| brillo::Blob fec(block_size * fec_roots); |
| for (size_t j = 0; j < block_size; j++) { |
| // Encode [j * rs_n : (j + 1) * rs_n) in |rs_blocks| and write |
| // |fec_roots| number of parity bytes to |j * fec_roots| in |fec|. |
| encode_rs_char(rs_char.get(), |
| rs_blocks.data() + j * rs_n, |
| fec.data() + j * fec_roots); |
| } |
| |
| if (verify_mode) { |
| brillo::Blob fec_read(fec.size()); |
| ssize_t bytes_read = 0; |
| TEST_AND_RETURN_FALSE(utils::PReadAll( |
| read_fd, fec_read.data(), fec_read.size(), fec_offset, &bytes_read)); |
| TEST_AND_RETURN_FALSE(bytes_read >= 0); |
| TEST_AND_RETURN_FALSE(static_cast<size_t>(bytes_read) == fec_read.size()); |
| TEST_AND_RETURN_FALSE(fec == fec_read); |
| } else { |
| CHECK(write_fd); |
| write_fd->Seek(fec_offset, SEEK_SET); |
| if (!utils::WriteAll(write_fd, fec.data(), fec.size())) { |
| PLOG(ERROR) << "EncodeFEC write() failed"; |
| return false; |
| } |
| } |
| fec_offset += fec.size(); |
| } |
| write_fd->Flush(); |
| return true; |
| } |
| |
| bool VerityWriterAndroid::EncodeFEC(const std::string& path, |
| uint64_t data_offset, |
| uint64_t data_size, |
| uint64_t fec_offset, |
| uint64_t fec_size, |
| uint32_t fec_roots, |
| uint32_t block_size, |
| bool verify_mode) { |
| EintrSafeFileDescriptor fd; |
| TEST_AND_RETURN_FALSE(fd.Open(path.c_str(), verify_mode ? O_RDONLY : O_RDWR)); |
| return EncodeFEC(&fd, |
| &fd, |
| data_offset, |
| data_size, |
| fec_offset, |
| fec_size, |
| fec_roots, |
| block_size, |
| verify_mode); |
| } |
| } // namespace chromeos_update_engine |