Merge "Add chunk-level checksum to RecordedTransaction" am: bcb91683b1 (53cc415e) · Commits · e / os / platform_frameworks_native

libs/binder/BinderRecordReplay.cpp

+133 −110

Original line number	Diff line number	Diff line
		@@ -18,6 +18,7 @@
		#include <android-base/logging.h>
		#include <android-base/unique_fd.h>
		#include <binder/BinderRecordReplay.h>
		#include <sys/mman.h>
		#include <algorithm>

		using android::Parcel;
		@@ -42,34 +43,38 @@ static_assert(PADDING8(8) == 0);
		//
		// A RecordedTransaction is written to a file as a sequence of Chunks.
		//
		// A Chunk consists of a ChunkDescriptor, Data, and Padding.
		// A Chunk consists of a ChunkDescriptor, Data, Padding, and a Checksum.
		//
		// Data and Padding may each be zero-length as specified by the
		// ChunkDescriptor.
		// The ChunkDescriptor identifies the type of Data in the chunk, and the size
		// of the Data.
		//
		// The ChunkDescriptor identifies the type of data in the chunk, the size of
		// the data in bytes, and the number of zero-bytes padding to land on an
		// 8-byte boundary by the end of the Chunk.
		// The Data may be any uint32 number of bytes in length in [0-0xfffffff0].
		//
		// Padding is between [0-7] zero-bytes after the Data such that the Chunk ends
		// on an 8-byte boundary. The ChunkDescriptor's dataSize does not include the
		// size of Padding.
		//
		// The checksum is a 64-bit wide XOR of all previous data from the start of the
		// ChunkDescriptor to the end of Padding.
		//
		// ┌───────────────────────────┐
		// │Chunk │
		// │┌─────────────────────────┐│
		// │┌────────────────────────┐ │
		// ││ChunkDescriptor │ │
		// ││┌───────────┬───────────┐││
		// │││chunkType │paddingSize│││
		// │││uint32_t │uint32_t ├┼┼───┐
		// ││├───────────┴───────────┤││ │
		// │││dataSize │││ │
		// │││uint64_t ├┼┼─┐ │
		// ││└───────────────────────┘││ │ │
		// │└─────────────────────────┘│ │ │
		// │┌─────────────────────────┐│ │ │
		// ││Data ││ │ │
		// ││bytes * dataSize │◀─┘ │
		// │└─────────────────────────┘│ │
		// ││┌───────────┬──────────┐│ │
		// │││chunkType │dataSize ├┼─┼─┐
		// │││uint32_t │uint32_t ││ │ │
		// ││└───────────┴──────────┘│ │ │
		// │└────────────────────────┘ │ │
		// │┌─────────────────────────┐│ │
		// ││Padding ││ │
		// ││bytes * paddingSize │◀───┘
		// ││Data ││ │
		// ││bytes * dataSize │◀─┘
		// ││ ┌ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┤│
		// ││ Padding ││
		// │└───┴─────────────────────┘│
		// │┌─────────────────────────┐│
		// ││checksum ││
		// ││uint64_t ││
		// │└─────────────────────────┘│
		// └───────────────────────────┘
		//
		@@ -85,20 +90,20 @@ static_assert(PADDING8(8) == 0);
		// ║ End Chunk ║
		// ╚══════════════════════╝
		//
		// On reading a RecordedTransaction, an unrecognized chunk is skipped using
		// the size information in the ChunkDescriptor. Chunks are read and either
		// assimilated or skipped until an End Chunk is encountered. This has three
		// notable implications:
		// On reading a RecordedTransaction, an unrecognized chunk is checksummed
		// then skipped according to size information in the ChunkDescriptor. Chunks
		// are read and either assimilated or skipped until an End Chunk is
		// encountered. This has three notable implications:
		//
		// 1. Older and newer implementations should be able to read one another's
		// Transactions, though there will be loss of information.
		// 2. With the exception of the End Chunk, Chunks can appear in any
		// order and even repeat, though this is not recommended.
		// 2. With the exception of the End Chunk, Chunks can appear in any order
		// and even repeat, though this is not recommended.
		// 3. If any Chunk is repeated, old values will be overwritten by versions
		// encountered later in the file.
		//
		// No effort is made to ensure the expected chunks are present. A single
		// End Chunk may therefore produce a empty, meaningless RecordedTransaction.
		// End Chunk may therefore produce an empty, meaningless RecordedTransaction.

		RecordedTransaction::RecordedTransaction(RecordedTransaction&& t) noexcept {
		mHeader = t.mHeader;
		@@ -121,12 +126,12 @@ std::optional<RecordedTransaction> RecordedTransaction::fromDetails(uint32_t cod
		0};

		if (t.mSent.setData(dataParcel.data(), dataParcel.dataSize()) != android::NO_ERROR) {
		LOG(INFO) << "Failed to set sent parcel data.";
		LOG(ERROR) << "Failed to set sent parcel data.";
		return std::nullopt;
		}

		if (t.mReply.setData(replyParcel.data(), replyParcel.dataSize()) != android::NO_ERROR) {
		LOG(INFO) << "Failed to set reply parcel data.";
		LOG(ERROR) << "Failed to set reply parcel data.";
		return std::nullopt;
		}

		@@ -134,94 +139,111 @@ std::optional<RecordedTransaction> RecordedTransaction::fromDetails(uint32_t cod
		}

		enum {
		HEADER_CHUNK = 0x00000001,
		DATA_PARCEL_CHUNK = 0x00000002,
		REPLY_PARCEL_CHUNK = 0x00000003,
		INVALID_CHUNK = 0x00fffffe,
		HEADER_CHUNK = 1,
		DATA_PARCEL_CHUNK = 2,
		REPLY_PARCEL_CHUNK = 3,
		END_CHUNK = 0x00ffffff,
		};

		struct ChunkDescriptor {
		uint32_t chunkType = 0;
		uint32_t padding = 0;
		uint32_t dataSize = 0;
		uint32_t reserved = 0; // Future checksum
		};
		static_assert(sizeof(ChunkDescriptor) % 8 == 0);

		constexpr uint32_t kMaxChunkDataSize = 0xfffffff0;
		typedef uint64_t transaction_checksum_t;

		static android::status_t readChunkDescriptor(borrowed_fd fd, ChunkDescriptor* chunkOut) {
		static android::status_t readChunkDescriptor(borrowed_fd fd, ChunkDescriptor* chunkOut,
		transaction_checksum_t* sum) {
		if (!android::base::ReadFully(fd, chunkOut, sizeof(ChunkDescriptor))) {
		LOG(INFO) << "Failed to read Chunk Descriptor from fd " << fd.get();
		LOG(ERROR) << "Failed to read Chunk Descriptor from fd " << fd.get();
		return android::UNKNOWN_ERROR;
		}
		if (PADDING8(chunkOut->dataSize) != chunkOut->padding) {
		chunkOut->chunkType = INVALID_CHUNK;
		LOG(INFO) << "Chunk data and padding sizes do not align." << fd.get();
		return android::BAD_VALUE;
		}

		sum ^= reinterpret_cast<transaction_checksum_t*>(chunkOut);
		return android::NO_ERROR;
		}

		std::optional<RecordedTransaction> RecordedTransaction::fromFile(const unique_fd& fd) {
		RecordedTransaction t;
		ChunkDescriptor chunk;

		const long pageSize = sysconf(_SC_PAGE_SIZE);
		do {
		if (NO_ERROR != readChunkDescriptor(fd, &chunk)) {
		LOG(INFO) << "Failed to read chunk descriptor.";
		transaction_checksum_t checksum = 0;
		if (NO_ERROR != readChunkDescriptor(fd, &chunk, &checksum)) {
		LOG(ERROR) << "Failed to read chunk descriptor.";
		return std::nullopt;
		}
		off_t fdCurrentPosition = lseek(fd.get(), 0, SEEK_CUR);
		off_t mmapPageAlignedStart = (fdCurrentPosition / pageSize) * pageSize;
		off_t mmapPayloadStartOffset = fdCurrentPosition - mmapPageAlignedStart;

		if (chunk.dataSize > kMaxChunkDataSize) {
		LOG(ERROR) << "Chunk data exceeds maximum size.";
		return std::nullopt;
		}

		size_t chunkPayloadSize =
		chunk.dataSize + PADDING8(chunk.dataSize) + sizeof(transaction_checksum_t);

		if (PADDING8(chunkPayloadSize) != 0) {
		LOG(ERROR) << "Invalid chunk size, not aligned " << chunkPayloadSize;
		return std::nullopt;
		}

		transaction_checksum_t* payloadMap = reinterpret_cast<transaction_checksum_t*>(
		mmap(NULL, chunkPayloadSize + mmapPayloadStartOffset, PROT_READ, MAP_SHARED,
		fd.get(), mmapPageAlignedStart));
		payloadMap += mmapPayloadStartOffset /
		sizeof(transaction_checksum_t); // Skip chunk descriptor and required mmap
		// page-alignment
		if (payloadMap == MAP_FAILED) {
		LOG(ERROR) << "Memory mapping failed for fd " << fd.get() << ": " << errno << " "
		<< strerror(errno);
		return std::nullopt;
		}
		for (size_t checksumIndex = 0;
		checksumIndex < chunkPayloadSize / sizeof(transaction_checksum_t); checksumIndex++) {
		checksum ^= payloadMap[checksumIndex];
		}
		if (checksum != 0) {
		LOG(ERROR) << "Checksum failed.";
		return std::nullopt;
		}
		lseek(fd.get(), chunkPayloadSize, SEEK_CUR);

		switch (chunk.chunkType) {
		case HEADER_CHUNK: {
		if (chunk.dataSize != static_cast<uint32_t>(sizeof(TransactionHeader))) {
		LOG(INFO) << "Header Chunk indicated size " << chunk.dataSize << "; Expected "
		LOG(ERROR) << "Header Chunk indicated size " << chunk.dataSize << "; Expected "
		<< sizeof(TransactionHeader) << ".";
		return std::nullopt;
		}
		if (!android::base::ReadFully(fd, &t.mHeader, chunk.dataSize)) {
		LOG(INFO) << "Failed to read transactionHeader from fd " << fd.get();
		return std::nullopt;
		}
		lseek(fd.get(), chunk.padding, SEEK_CUR);
		t.mHeader = reinterpret_cast<TransactionHeader>(payloadMap);
		break;
		}
		case DATA_PARCEL_CHUNK: {
		std::vector<uint8_t> bytes;
		bytes.resize(chunk.dataSize);
		if (!android::base::ReadFully(fd, bytes.data(), chunk.dataSize)) {
		LOG(INFO) << "Failed to read sent parcel data from fd " << fd.get();
		if (t.mSent.setData(reinterpret_cast<const unsigned char*>(payloadMap),
		chunk.dataSize) != android::NO_ERROR) {
		LOG(ERROR) << "Failed to set sent parcel data.";
		return std::nullopt;
		}
		if (t.mSent.setData(bytes.data(), chunk.dataSize) != android::NO_ERROR) {
		LOG(INFO) << "Failed to set sent parcel data.";
		return std::nullopt;
		}
		lseek(fd.get(), chunk.padding, SEEK_CUR);
		break;
		}
		case REPLY_PARCEL_CHUNK: {
		std::vector<uint8_t> bytes;
		bytes.resize(chunk.dataSize);
		if (!android::base::ReadFully(fd, bytes.data(), chunk.dataSize)) {
		LOG(INFO) << "Failed to read reply parcel data from fd " << fd.get();
		if (t.mReply.setData(reinterpret_cast<const unsigned char*>(payloadMap),
		chunk.dataSize) != android::NO_ERROR) {
		LOG(ERROR) << "Failed to set reply parcel data.";
		return std::nullopt;
		}
		if (t.mReply.setData(bytes.data(), chunk.dataSize) != android::NO_ERROR) {
		LOG(INFO) << "Failed to set reply parcel data.";
		return std::nullopt;
		}
		lseek(fd.get(), chunk.padding, SEEK_CUR);
		break;
		}
		case INVALID_CHUNK:
		LOG(INFO) << "Invalid chunk.";
		return std::nullopt;
		case END_CHUNK:
		LOG(INFO) << "Read end chunk";
		FALLTHROUGH_INTENDED;
		default:
		// Unrecognized or skippable chunk
		lseek(fd.get(), chunk.dataSize + chunk.padding, SEEK_CUR);
		break;
		default:
		LOG(INFO) << "Unrecognized chunk.";
		continue;
		}
		} while (chunk.chunkType != END_CHUNK);

		@@ -230,36 +252,37 @@ std::optional<RecordedTransaction> RecordedTransaction::fromFile(const unique_fd

		android::status_t RecordedTransaction::writeChunk(borrowed_fd fd, uint32_t chunkType,
		size_t byteCount, const uint8_t* data) const {
		// Write Chunk Descriptor
		// - Chunk Type
		if (!android::base::WriteFully(fd, &chunkType, sizeof(uint32_t))) {
		LOG(INFO) << "Failed to write chunk header to fd " << fd.get();
		return UNKNOWN_ERROR;
		}
		// - Chunk Data Padding Size
		uint32_t additionalPaddingCount = static_cast<uint32_t>(PADDING8(byteCount));
		if (!android::base::WriteFully(fd, &additionalPaddingCount, sizeof(uint32_t))) {
		LOG(INFO) << "Failed to write chunk padding size to fd " << fd.get();
		return UNKNOWN_ERROR;
		}
		// - Chunk Data Size
		uint64_t byteCountToWrite = (uint64_t)byteCount;
		if (!android::base::WriteFully(fd, &byteCountToWrite, sizeof(uint64_t))) {
		LOG(INFO) << "Failed to write chunk size to fd " << fd.get();
		return UNKNOWN_ERROR;
		}
		if (byteCount == 0) {
		return NO_ERROR;
		}
		if (byteCount > kMaxChunkDataSize) {
		LOG(ERROR) << "Chunk data exceeds maximum size";
		return BAD_VALUE;
		}
		ChunkDescriptor descriptor = {.chunkType = chunkType,
		.dataSize = static_cast<uint32_t>(byteCount)};
		// Prepare Chunk content as byte *
		const std::byte* descriptorBytes = reinterpret_cast<const std::byte*>(&descriptor);
		const std::byte* dataBytes = reinterpret_cast<const std::byte*>(data);

		if (!android::base::WriteFully(fd, data, byteCount)) {
		LOG(INFO) << "Failed to write chunk data to fd " << fd.get();
		return UNKNOWN_ERROR;
		// Add Chunk to intermediate buffer, except checksum
		std::vector<std::byte> buffer;
		buffer.insert(buffer.end(), descriptorBytes, descriptorBytes + sizeof(ChunkDescriptor));
		buffer.insert(buffer.end(), dataBytes, dataBytes + byteCount);
		std::byte zero{0};
		buffer.insert(buffer.end(), PADDING8(byteCount), zero);

		// Calculate checksum from buffer
		transaction_checksum_t* checksumData = reinterpret_cast<transaction_checksum_t*>(buffer.data());
		transaction_checksum_t checksumValue = 0;
		for (size_t idx = 0; idx < (buffer.size() / sizeof(transaction_checksum_t)); idx++) {
		checksumValue ^= checksumData[idx];
		}

		const uint8_t zeros[7] = {0};
		if (!android::base::WriteFully(fd, zeros, additionalPaddingCount)) {
		LOG(INFO) << "Failed to write chunk padding to fd " << fd.get();
		// Write checksum to buffer
		std::byte* checksumBytes = reinterpret_cast<std::byte*>(&checksumValue);
		buffer.insert(buffer.end(), checksumBytes, checksumBytes + sizeof(transaction_checksum_t));

		// Write buffer to file
		if (!android::base::WriteFully(fd, buffer.data(), buffer.size())) {
		LOG(ERROR) << "Failed to write chunk fd " << fd.get();
		return UNKNOWN_ERROR;
		}
		return NO_ERROR;
		@@ -269,19 +292,19 @@ android::status_t RecordedTransaction::dumpToFile(const unique_fd& fd) const {
		if (NO_ERROR !=
		writeChunk(fd, HEADER_CHUNK, sizeof(TransactionHeader),
		reinterpret_cast<const uint8_t*>(&mHeader))) {
		LOG(INFO) << "Failed to write transactionHeader to fd " << fd.get();
		LOG(ERROR) << "Failed to write transactionHeader to fd " << fd.get();
		return UNKNOWN_ERROR;
		}
		if (NO_ERROR != writeChunk(fd, DATA_PARCEL_CHUNK, mSent.dataSize(), mSent.data())) {
		LOG(INFO) << "Failed to write sent Parcel to fd " << fd.get();
		LOG(ERROR) << "Failed to write sent Parcel to fd " << fd.get();
		return UNKNOWN_ERROR;
		}
		if (NO_ERROR != writeChunk(fd, REPLY_PARCEL_CHUNK, mReply.dataSize(), mReply.data())) {
		LOG(INFO) << "Failed to write reply Parcel to fd " << fd.get();
		LOG(ERROR) << "Failed to write reply Parcel to fd " << fd.get();
		return UNKNOWN_ERROR;
		}
		if (NO_ERROR != writeChunk(fd, END_CHUNK, 0, NULL)) {
		LOG(INFO) << "Failed to write end chunk to fd " << fd.get();
		LOG(ERROR) << "Failed to write end chunk to fd " << fd.get();
		return UNKNOWN_ERROR;
		}
		return NO_ERROR;

libs/binder/tests/binderRecordedTransactionTest.cpp

+78 −0

Original line number	Diff line number	Diff line
		@@ -16,6 +16,7 @@

		#include <binder/BinderRecordReplay.h>
		#include <gtest/gtest.h>
		#include <utils/Errors.h>

		using android::Parcel;
		using android::status_t;
		@@ -54,3 +55,80 @@ TEST(BinderRecordedTransaction, RoundTripEncoding) {
		EXPECT_EQ(retrievedTransaction->getDataParcel().readInt64(), 2);
		EXPECT_EQ(retrievedTransaction->getReplyParcel().readInt32(), 99);
		}

		TEST(BinderRecordedTransaction, Checksum) {
		Parcel d;
		d.writeInt32(12);
		d.writeInt64(2);
		Parcel r;
		r.writeInt32(99);
		timespec ts = {1232456, 567890};
		auto transaction = RecordedTransaction::fromDetails(1, 42, ts, d, r, 0);

		auto file = std::tmpfile();
		auto fd = unique_fd(fcntl(fileno(file), F_DUPFD, 1));

		status_t status = transaction->dumpToFile(fd);
		ASSERT_EQ(android::NO_ERROR, status);

		lseek(fd.get(), 9, SEEK_SET);
		uint32_t badData = 0xffffffff;
		write(fd.get(), &badData, sizeof(uint32_t));
		std::rewind(file);

		auto retrievedTransaction = RecordedTransaction::fromFile(fd);

		EXPECT_FALSE(retrievedTransaction.has_value());
		}

		TEST(BinderRecordedTransaction, PayloadsExceedPageBoundaries) {
		// File contents are read with mmap.
		// This test verifies that transactions are read from portions
		// of files that cross page boundaries and don't start at a
		// page boundary offset of the fd.
		const size_t pageSize = sysconf(_SC_PAGE_SIZE);
		const size_t largeDataSize = pageSize + 100;
		std::vector<uint8_t> largePayload;
		uint8_t filler = 0xaa;
		largePayload.insert(largePayload.end(), largeDataSize, filler);
		Parcel d;
		d.writeInt32(12);
		d.writeInt64(2);
		d.writeByteVector(largePayload);
		Parcel r;
		r.writeInt32(99);
		timespec ts = {1232456, 567890};
		auto transaction = RecordedTransaction::fromDetails(1, 42, ts, d, r, 0);

		auto file = std::tmpfile();
		auto fd = unique_fd(fcntl(fileno(file), F_DUPFD, 1));

		// Write to file twice
		status_t status = transaction->dumpToFile(fd);
		ASSERT_EQ(android::NO_ERROR, status);
		status = transaction->dumpToFile(fd);
		ASSERT_EQ(android::NO_ERROR, status);

		std::rewind(file);

		for (int i = 0; i < 2; i++) {
		auto retrievedTransaction = RecordedTransaction::fromFile(fd);

		EXPECT_EQ(retrievedTransaction->getCode(), 1);
		EXPECT_EQ(retrievedTransaction->getFlags(), 42);
		EXPECT_EQ(retrievedTransaction->getTimestamp().tv_sec, ts.tv_sec);
		EXPECT_EQ(retrievedTransaction->getTimestamp().tv_nsec, ts.tv_nsec);
		EXPECT_EQ(retrievedTransaction->getDataParcel().dataSize(), d.dataSize());
		EXPECT_EQ(retrievedTransaction->getReplyParcel().dataSize(), 4);
		EXPECT_EQ(retrievedTransaction->getReturnedStatus(), 0);
		EXPECT_EQ(retrievedTransaction->getVersion(), 0);

		EXPECT_EQ(retrievedTransaction->getDataParcel().readInt32(), 12);
		EXPECT_EQ(retrievedTransaction->getDataParcel().readInt64(), 2);
		std::optional<std::vector<uint8_t>> payloadOut;
		EXPECT_EQ(retrievedTransaction->getDataParcel().readByteVector(&payloadOut), android::OK);
		EXPECT_EQ(payloadOut.value(), largePayload);

		EXPECT_EQ(retrievedTransaction->getReplyParcel().readInt32(), 99);
		}
		}