[Flow EVM] COA ownership proof - part 2

fvm/evm/handler/handler.go

@@ -2,6 +2,7 @@ package handler
 
 import (
 	"bytes"
+	"fmt"
 	"math/big"
 
 	gethCommon "github.com/ethereum/go-ethereum/common"
@@ -57,6 +58,9 @@ func getPrecompiles(
 	archContract := precompiles.ArchContract(
 		archAddress,
 		backend.GetCurrentBlockHeight,
+		func(cpic *types.COAOwnershipProofInContext) (bool, error) {
+			return false, fmt.Errorf("not implemented")
+		},
 	)
 	return []types.Precompile{archContract}
 }

fvm/evm/precompiles/abi.go

@@ -0,0 +1,223 @@
+package precompiles
+
+import (
+	"encoding/binary"
+	"errors"
+	"math/big"
+
+	gethCommon "github.com/ethereum/go-ethereum/common"
+)
+
+// This package provides fast and effient
+// utilities needed for abi encoding and decoding
+// encodings are mostly used for testing purpose
+// if more complex encoding and decoding is needed please
+// use the abi package and pass teh ABIs, though
+// that has a performance overhead.
+const (
+	FixedSizeUnitDataReadSize = 32
+	Bytes4DataReadSize        = 4
+	Bytes8DataReadSize        = 8
+	Bytes32DataReadSize       = 32
+	Uint64ByteSize            = 8
+
+	EncodedBoolSize    = FixedSizeUnitDataReadSize
+	EncodedAddressSize = FixedSizeUnitDataReadSize
+	EncodedBytes32Size = FixedSizeUnitDataReadSize
+	EncodedBytes4Size  = FixedSizeUnitDataReadSize
+	EncodedBytes8Size  = FixedSizeUnitDataReadSize
+	EncodedUint64Size  = FixedSizeUnitDataReadSize
+	EncodedUint256Size = FixedSizeUnitDataReadSize
+)
+
+var ErrInputDataTooSmall = errors.New("input data is too small for decoding")
+var ErrBufferTooSmall = errors.New("buffer too small for encoding")
+var ErrDataTooLarge = errors.New("input data is too large for encoding")
+
+// ReadAddress reads an address from the buffer at index
+func ReadAddress(buffer []byte, index int) (gethCommon.Address, error) {
+	if len(buffer) < index+FixedSizeUnitDataReadSize {
+		return gethCommon.Address{}, ErrInputDataTooSmall
+	}
+	paddedData := buffer[index : index+FixedSizeUnitDataReadSize]
+	// addresses are zero-padded on the left side.
+	addr := gethCommon.BytesToAddress(
+		paddedData[FixedSizeUnitDataReadSize-gethCommon.AddressLength:])
+	return addr, nil
+}
+
+// EncodeBool encodes boolean into fixed size unit of encoded data
+func EncodeAddress(address gethCommon.Address, buffer []byte, index int) error {
+	if len(buffer) < index+EncodedAddressSize {
+		return ErrBufferTooSmall
+	}
+	copy(buffer[index:index+EncodedAddressSize],
+		gethCommon.LeftPadBytes(address[:], EncodedAddressSize))
+	return nil
+}
+
+// ReadBool reads a boolean from the buffer at the index
+func ReadBool(buffer []byte, index int) (bool, error) {
+	if len(buffer) < index+EncodedBoolSize {
+		return false, ErrInputDataTooSmall
+	}
+	// bools are zero-padded on the left side
+	// so we only need to read the last byte
+	return uint8(buffer[index+EncodedBoolSize-1]) > 0, nil
+}
+
+// EncodeBool encodes a boolean into fixed size unit of encoded data
+func EncodeBool(bitSet bool, buffer []byte, index int) error {
+	if len(buffer) < index+EncodedBoolSize {
+		return ErrBufferTooSmall
+	}
+	var bitSetVar uint8
+	if bitSet {
+		bitSetVar = 1
+	}
+	copy(buffer[index:index+EncodedBoolSize],
+		gethCommon.LeftPadBytes(
+			[]byte{bitSetVar},
+			EncodedBoolSize,
+		),
+	)
+	return nil
+}
+
+// ReadUint64 reads a uint64 from the buffer at index
+func ReadUint64(buffer []byte, index int) (uint64, error) {
+	if len(buffer) < index+EncodedUint64Size {
+		return 0, ErrInputDataTooSmall
+	}
+	// data is expected to be big endian (zero-padded on the left side)
+	return binary.BigEndian.Uint64(
+		buffer[index+EncodedUint64Size-Uint64ByteSize : index+EncodedUint64Size]), nil
+}
+
+// EncodeUint64 encodes a uint64 into fixed size unit of encoded data (zero-padded on the left side)
+func EncodeUint64(inp uint64, buffer []byte, index int) error {
+	if len(buffer) < index+EncodedUint64Size {
+		return ErrBufferTooSmall
+	}
+	encoded := make([]byte, 8)
+	binary.BigEndian.PutUint64(encoded, inp)
+	copy(buffer[index:index+EncodedUint64Size],
+		gethCommon.LeftPadBytes(encoded, EncodedUint64Size),
+	)
+	return nil
+}
+
+// ReadUint256 reads an address from the buffer at index
+func ReadUint256(buffer []byte, index int) (*big.Int, error) {
+	if len(buffer) < index+EncodedUint256Size {
+		return nil, ErrInputDataTooSmall
+	}
+	// data is expected to be big endian (zero-padded on the left side)
+	return new(big.Int).SetBytes(buffer[index : index+EncodedUint256Size]), nil
+}
+
+// ReadBytes4 reads a 4 byte slice from the buffer at index
+func ReadBytes4(buffer []byte, index int) ([]byte, error) {
+	if len(buffer) < index+Bytes4DataReadSize {
+		return nil, ErrInputDataTooSmall
+	}
+	// fixed-size byte values are zero-padded on the right side.
+	return buffer[index : index+Bytes4DataReadSize], nil
+}
+
+// ReadBytes8 reads a 8 byte slice from the buffer at index
+func ReadBytes8(buffer []byte, index int) ([]byte, error) {
+	if len(buffer) < index+Bytes8DataReadSize {
+		return nil, ErrInputDataTooSmall
+	}
+	// fixed-size byte values are zero-padded on the right side.
+	return buffer[index : index+Bytes8DataReadSize], nil
+}
+
+// ReadBytes32 reads a 32 byte slice from the buffer at index
+func ReadBytes32(buffer []byte, index int) ([]byte, error) {
+	if len(buffer) < index+Bytes32DataReadSize {
+		return nil, ErrInputDataTooSmall
+	}
+	return buffer[index : index+Bytes32DataReadSize], nil
+}
+
+// EncodeBytes32 encodes data into a bytes 32
+func EncodeBytes32(data []byte, buffer []byte, index int) error {
+	if len(data) > EncodedBytes32Size {
+		return ErrDataTooLarge
+	}
+	if len(buffer) < index+EncodedBytes32Size {
+		return ErrBufferTooSmall
+	}
+	copy(buffer[index:index+EncodedBytes32Size],
+		gethCommon.RightPadBytes(data, EncodedBytes32Size),
+	)
+	return nil
+}
+
+// ReadBytes reads a variable length bytes from the buffer
+func ReadBytes(buffer []byte, index int) ([]byte, error) {
+	if len(buffer) < index+EncodedUint64Size {
+		return nil, ErrInputDataTooSmall
+	}
+	// reading offset (we read into uint64) and adjust index
+	offset, err := ReadUint64(buffer, index)
+	if err != nil {
+		return nil, err
+	}
+	index = int(offset)
+	if len(buffer) < index+EncodedUint64Size {
+		return nil, ErrInputDataTooSmall
+	}
+	// reading length of byte slice
+	length, err := ReadUint64(buffer, index)
+	if err != nil {
+		return nil, err
+	}
+	index += EncodedUint64Size
+	if len(buffer) < index+int(length) {
+		return nil, ErrInputDataTooSmall
+	}
+	return buffer[index : index+int(length)], nil
+}
+
+// SizeNeededForBytesEncoding computes the number of bytes needed for bytes encoding
+func SizeNeededForBytesEncoding(data []byte) int {
+	paddedSize := (len(data) / FixedSizeUnitDataReadSize) + FixedSizeUnitDataReadSize
+	return EncodedUint64Size + EncodedUint64Size + paddedSize
+}
+
+// EncodeBytes encodes the data into the buffer at index and append payload to the
+// end of buffer
+func EncodeBytes(data []byte, buffer []byte, headerIndex, payloadIndex int) error {
+	//// updating offset
+	if len(buffer) < headerIndex+EncodedUint64Size {
+		return ErrBufferTooSmall
+	}
+	err := EncodeUint64(uint64(payloadIndex), buffer, headerIndex)
+	if err != nil {
+		return err
+	}
+	headerIndex += EncodedUint64Size
+
+	//// updating payload
+	// padding data
+	dataSize := len(data)
+	paddedSize := (dataSize / FixedSizeUnitDataReadSize) + FixedSizeUnitDataReadSize
+	if dataSize%FixedSizeUnitDataReadSize != 0 {
+		data = gethCommon.RightPadBytes(data, paddedSize)
+	}
+	if len(buffer) < payloadIndex+EncodedUint64Size+paddedSize {
+		return ErrBufferTooSmall
+	}
+	// adding length
+	err = EncodeUint64(uint64(dataSize), buffer, payloadIndex)
+	if err != nil {
+		return err
+	}
+	payloadIndex += EncodedUint64Size
+	// adding data
+	copy(buffer[payloadIndex:payloadIndex+len(data)], data)
+	return nil
+}

fvm/evm/precompiles/abi_test.go

@@ -0,0 +1,92 @@
+package precompiles_test
+
+import (
+	"encoding/hex"
+	"testing"
+
+	gethCommon "github.com/ethereum/go-ethereum/common"
+	"github.com/stretchr/testify/require"
+
+	"github.com/onflow/flow-go/fvm/evm/precompiles"
+)
+
+func TestABIEncodingDecodingFunctions(t *testing.T) {
+	t.Parallel()
+
+	t.Run("test address", func(t *testing.T) {
+		encodedAddress, err := hex.DecodeString("000000000000000000000000e592427a0aece92de3edee1f18e0157c05861564")
+		require.NoError(t, err)
+		addr, err := precompiles.ReadAddress(encodedAddress, 0)
+		require.NoError(t, err)
+		expectedAddress := gethCommon.HexToAddress("e592427a0aece92de3edee1f18e0157c05861564")
+		require.Equal(t, expectedAddress, addr)
+		reEncoded := make([]byte, precompiles.EncodedAddressSize)
+		err = precompiles.EncodeAddress(addr, reEncoded, 0)
+		require.NoError(t, err)
+		require.Equal(t, encodedAddress, reEncoded)
+	})
+
+	t.Run("test boolean", func(t *testing.T) {
+		encodedBool, err := hex.DecodeString("0000000000000000000000000000000000000000000000000000000000000001")
+		require.NoError(t, err)
+		ret, err := precompiles.ReadBool(encodedBool, 0)
+		require.NoError(t, err)
+		require.True(t, ret)
+		reEncoded := make([]byte, precompiles.EncodedBoolSize)
+		err = precompiles.EncodeBool(ret, reEncoded, 0)
+		require.NoError(t, err)
+		require.Equal(t, encodedBool, reEncoded)
+	})
+
+	t.Run("test uint64", func(t *testing.T) {
+		encodedUint64, err := hex.DecodeString("0000000000000000000000000000000000000000000000000000000000000046")
+		require.NoError(t, err)
+		ret, err := precompiles.ReadUint64(encodedUint64, 0)
+		require.NoError(t, err)
+		expectedUint64 := uint64(70)
+		require.Equal(t, expectedUint64, ret)
+		reEncoded := make([]byte, precompiles.EncodedUint64Size)
+		err = precompiles.EncodeUint64(ret, reEncoded, 0)
+		require.NoError(t, err)
+		require.Equal(t, encodedUint64, reEncoded)
+
+	})
+
+	t.Run("test fixed size bytes", func(t *testing.T) {
+		encodedFixedSizeBytes, err := hex.DecodeString("abcdef1200000000000000000000000000000000000000000000000000000000")
+		require.NoError(t, err)
+		ret, err := precompiles.ReadBytes4(encodedFixedSizeBytes, 0)
+		require.NoError(t, err)
+		require.Equal(t, encodedFixedSizeBytes[0:4], ret)
+
+		ret, err = precompiles.ReadBytes8(encodedFixedSizeBytes, 0)
+		require.NoError(t, err)
+		require.Equal(t, encodedFixedSizeBytes[0:8], ret)
+
+		ret, err = precompiles.ReadBytes32(encodedFixedSizeBytes, 0)
+		require.NoError(t, err)
+		require.Equal(t, encodedFixedSizeBytes[0:32], ret)
+
+		reEncoded := make([]byte, precompiles.EncodedBytes32Size)
+		err = precompiles.EncodeBytes32(ret, reEncoded, 0)
+		require.NoError(t, err)
+		require.Equal(t, encodedFixedSizeBytes, reEncoded)
+	})
+
+	t.Run("test read bytes (variable size)", func(t *testing.T) {
+		encodedData, err := hex.DecodeString("0000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000b48656c6c6f20576f726c64000000000000000000000000000000000000000000")
+		require.NoError(t, err)
+
+		ret, err := precompiles.ReadBytes(encodedData, 0)
+		require.NoError(t, err)
+		expectedData, err := hex.DecodeString("48656c6c6f20576f726c64")
+		require.NoError(t, err)
+		require.Equal(t, expectedData, ret)
+
+		bufferSize := precompiles.SizeNeededForBytesEncoding(expectedData)
+		buffer := make([]byte, bufferSize)
+		err = precompiles.EncodeBytes(expectedData, buffer, 0, precompiles.EncodedUint64Size)
+		require.NoError(t, err)
+		require.Equal(t, encodedData, buffer)
+	})
+}