android13/system/update_engine/aosp/ota_extractor.cc

281 lines
11 KiB
C++

//
// Copyright (C) 2022 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 <array>
#include <cstdint>
#include <cstdio>
#include <iterator>
#include <memory>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <android-base/strings.h>
#include <base/files/file_path.h>
#include <gflags/gflags.h>
#include <unistd.h>
#include <xz.h>
#include "update_engine/common/utils.h"
#include "update_engine/common/hash_calculator.h"
#include "update_engine/payload_consumer/file_descriptor.h"
#include "update_engine/payload_consumer/file_descriptor_utils.h"
#include "update_engine/payload_consumer/install_operation_executor.h"
#include "update_engine/payload_consumer/payload_metadata.h"
#include "update_engine/payload_consumer/verity_writer_android.h"
#include "update_engine/update_metadata.pb.h"
DEFINE_string(payload, "", "Path to payload.bin");
DEFINE_string(
input_dir,
"",
"Directory to read input images. Only required for incremental OTAs");
DEFINE_string(output_dir, "", "Directory to put output images");
DEFINE_int64(payload_offset,
0,
"Offset to start of payload.bin. Useful if payload path actually "
"points to a .zip file containing payload.bin");
DEFINE_string(partitions,
"",
"Comma separated list of partitions to extract, leave empty for "
"extracting all partitions");
using chromeos_update_engine::DeltaArchiveManifest;
using chromeos_update_engine::PayloadMetadata;
namespace chromeos_update_engine {
void WriteVerity(const PartitionUpdate& partition,
FileDescriptorPtr fd,
const size_t block_size) {
// 512KB buffer, arbitrary value. Larger buffers may improve performance.
static constexpr size_t BUFFER_SIZE = 1024 * 512;
if (partition.hash_tree_extent().num_blocks() == 0 &&
partition.fec_extent().num_blocks() == 0) {
return;
}
InstallPlan::Partition install_part;
install_part.block_size = block_size;
CHECK(install_part.ParseVerityConfig(partition));
VerityWriterAndroid writer;
CHECK(writer.Init(install_part));
std::array<uint8_t, BUFFER_SIZE> buffer;
const auto data_size =
install_part.hash_tree_data_offset + install_part.hash_tree_data_size;
size_t offset = 0;
while (offset < data_size) {
const auto bytes_to_read =
static_cast<ssize_t>(std::min(BUFFER_SIZE, data_size - offset));
ssize_t bytes_read;
CHECK(
utils::ReadAll(fd, buffer.data(), bytes_to_read, offset, &bytes_read));
CHECK_EQ(bytes_read, bytes_to_read)
<< " Failed to read at offset " << offset << " "
<< android::base::ErrnoNumberAsString(errno);
writer.Update(offset, buffer.data(), bytes_read);
offset += bytes_read;
}
CHECK(writer.Finalize(fd.get(), fd.get()));
return;
}
bool ExtractImagesFromOTA(const DeltaArchiveManifest& manifest,
const PayloadMetadata& metadata,
int payload_fd,
size_t payload_offset,
std::string_view input_dir,
std::string_view output_dir,
const std::set<std::string>& partitions) {
InstallOperationExecutor executor(manifest.block_size());
const size_t data_begin = metadata.GetMetadataSize() +
metadata.GetMetadataSignatureSize() +
payload_offset;
const base::FilePath output_dir_path(
base::StringPiece(output_dir.data(), output_dir.size()));
const base::FilePath input_dir_path(
base::StringPiece(input_dir.data(), input_dir.size()));
std::vector<unsigned char> blob;
for (const auto& partition : manifest.partitions()) {
if (!partitions.empty() &&
partitions.count(partition.partition_name()) == 0) {
continue;
}
LOG(INFO) << "Extracting partition " << partition.partition_name()
<< " size: " << partition.new_partition_info().size();
const auto output_path =
output_dir_path.Append(partition.partition_name() + ".img").value();
auto out_fd =
std::make_shared<chromeos_update_engine::EintrSafeFileDescriptor>();
TEST_AND_RETURN_FALSE_ERRNO(
out_fd->Open(output_path.c_str(), O_RDWR | O_CREAT, 0644));
auto in_fd =
std::make_shared<chromeos_update_engine::EintrSafeFileDescriptor>();
if (partition.has_old_partition_info()) {
const auto input_path =
input_dir_path.Append(partition.partition_name() + ".img").value();
LOG(INFO) << "Incremental OTA detected for partition "
<< partition.partition_name() << " opening source image "
<< input_path;
CHECK(in_fd->Open(input_path.c_str(), O_RDONLY))
<< " failed to open " << input_path;
}
for (const auto& op : partition.operations()) {
if (op.has_src_sha256_hash()) {
brillo::Blob actual_hash;
TEST_AND_RETURN_FALSE(fd_utils::ReadAndHashExtents(
in_fd, op.src_extents(), manifest.block_size(), &actual_hash));
CHECK_EQ(HexEncode(ToStringView(actual_hash)),
HexEncode(op.src_sha256_hash()));
}
blob.resize(op.data_length());
const auto op_data_offset = data_begin + op.data_offset();
ssize_t bytes_read = 0;
TEST_AND_RETURN_FALSE(utils::PReadAll(
payload_fd, blob.data(), blob.size(), op_data_offset, &bytes_read));
if (op.has_data_sha256_hash()) {
brillo::Blob actual_hash;
TEST_AND_RETURN_FALSE(
HashCalculator::RawHashOfData(blob, &actual_hash));
CHECK_EQ(HexEncode(ToStringView(actual_hash)),
HexEncode(op.data_sha256_hash()));
}
auto direct_writer = std::make_unique<DirectExtentWriter>(out_fd);
if (op.type() == InstallOperation::ZERO) {
TEST_AND_RETURN_FALSE(executor.ExecuteZeroOrDiscardOperation(
op, std::move(direct_writer)));
} else if (op.type() == InstallOperation::REPLACE ||
op.type() == InstallOperation::REPLACE_BZ ||
op.type() == InstallOperation::REPLACE_XZ) {
TEST_AND_RETURN_FALSE(executor.ExecuteReplaceOperation(
op, std::move(direct_writer), blob.data(), blob.size()));
} else if (op.type() == InstallOperation::SOURCE_COPY) {
CHECK(in_fd->IsOpen());
TEST_AND_RETURN_FALSE(executor.ExecuteSourceCopyOperation(
op, std::move(direct_writer), in_fd));
} else {
CHECK(in_fd->IsOpen());
TEST_AND_RETURN_FALSE(executor.ExecuteDiffOperation(
op, std::move(direct_writer), in_fd, blob.data(), blob.size()));
}
}
WriteVerity(partition, out_fd, manifest.block_size());
int err =
truncate64(output_path.c_str(), partition.new_partition_info().size());
if (err) {
PLOG(ERROR) << "Failed to truncate " << output_path << " to "
<< partition.new_partition_info().size();
}
brillo::Blob actual_hash;
TEST_AND_RETURN_FALSE(
HashCalculator::RawHashOfFile(output_path, &actual_hash));
CHECK_EQ(HexEncode(ToStringView(actual_hash)),
HexEncode(partition.new_partition_info().hash()))
<< " Partition " << partition.partition_name()
<< " hash mismatches. Either the source image or OTA package is "
"corrupted.";
}
return true;
}
} // namespace chromeos_update_engine
namespace {
bool IsIncrementalOTA(const DeltaArchiveManifest& manifest) {
for (const auto& part : manifest.partitions()) {
if (part.has_old_partition_info()) {
return true;
}
}
return false;
}
} // namespace
int main(int argc, char* argv[]) {
gflags::SetUsageMessage(
"A tool to extract device images from Android OTA packages");
gflags::ParseCommandLineFlags(&argc, &argv, true);
xz_crc32_init();
auto tokens = android::base::Tokenize(FLAGS_partitions, ",");
const std::set<std::string> partitions(
std::make_move_iterator(tokens.begin()),
std::make_move_iterator(tokens.end()));
if (FLAGS_payload.empty()) {
LOG(ERROR) << "--payload <payload path> is required";
return 1;
}
if (!partitions.empty()) {
LOG(INFO) << "Extracting " << android::base::Join(partitions, ", ");
}
int payload_fd = open(FLAGS_payload.c_str(), O_RDONLY | O_CLOEXEC);
if (payload_fd < 0) {
PLOG(ERROR) << "Failed to open payload file";
return 1;
}
chromeos_update_engine::ScopedFdCloser closer{&payload_fd};
auto payload_size = chromeos_update_engine::utils::FileSize(payload_fd);
if (payload_size <= 0) {
PLOG(ERROR)
<< "Couldn't determine size of payload file, or payload file is empty";
return 1;
}
PayloadMetadata payload_metadata;
auto payload = static_cast<unsigned char*>(
mmap(nullptr, payload_size, PROT_READ, MAP_PRIVATE, payload_fd, 0));
if (payload == MAP_FAILED) {
PLOG(ERROR) << "Failed to mmap() payload file";
return 1;
}
auto munmap_deleter = [payload_size](auto payload) {
munmap(payload, payload_size);
};
std::unique_ptr<unsigned char, decltype(munmap_deleter)> munmapper{
payload, munmap_deleter};
if (payload_metadata.ParsePayloadHeader(payload + FLAGS_payload_offset,
payload_size - FLAGS_payload_offset,
nullptr) !=
chromeos_update_engine::MetadataParseResult::kSuccess) {
LOG(ERROR) << "Payload header parse failed!";
return 1;
}
DeltaArchiveManifest manifest;
if (!payload_metadata.GetManifest(payload + FLAGS_payload_offset,
payload_size - FLAGS_payload_offset,
&manifest)) {
LOG(ERROR) << "Failed to parse manifest!";
return 1;
}
if (IsIncrementalOTA(manifest) && FLAGS_input_dir.empty()) {
LOG(ERROR) << FLAGS_payload
<< " is an incremental OTA, --input_dir parameter is required.";
return 1;
}
return !ExtractImagesFromOTA(manifest,
payload_metadata,
payload_fd,
FLAGS_payload_offset,
FLAGS_input_dir,
FLAGS_output_dir,
partitions);
}