/
marshal.go
448 lines (353 loc) · 12.2 KB
/
marshal.go
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// Copyright 2020 The Swarm Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package mantaray
import (
"bytes"
"crypto/rand"
"encoding/binary"
"encoding/hex"
"encoding/json"
"errors"
"fmt"
)
const (
maxUint16 = ^uint16(0)
)
// Version constants.
const (
versionNameString = "mantaray"
versionCode01String = "0.1"
versionCode02String = "0.2"
versionSeparatorString = ":"
version01String = versionNameString + versionSeparatorString + versionCode01String // "mantaray:0.1"
version01HashString = "025184789d63635766d78c41900196b57d7400875ebe4d9b5d1e76bd9652a9b7" // pre-calculated version string, Keccak-256
version02String = versionNameString + versionSeparatorString + versionCode02String // "mantaray:0.2"
version02HashString = "5768b3b6a7db56d21d1abff40d41cebfc83448fed8d7e9b06ec0d3b073f28f7b" // pre-calculated version string, Keccak-256
)
// Node header fields constants.
const (
nodeObfuscationKeySize = 32
versionHashSize = 31
nodeRefBytesSize = 1
// nodeHeaderSize defines the total size of the header part
nodeHeaderSize = nodeObfuscationKeySize + versionHashSize + nodeRefBytesSize
)
// Node fork constats.
const (
nodeForkTypeBytesSize = 1
nodeForkPrefixBytesSize = 1
nodeForkHeaderSize = nodeForkTypeBytesSize + nodeForkPrefixBytesSize // 2
nodeForkPreReferenceSize = 32
nodePrefixMaxSize = nodeForkPreReferenceSize - nodeForkHeaderSize // 30
// "mantaray:0.2"
nodeForkMetadataBytesSize = 2
)
var (
version01HashBytes []byte
version02HashBytes []byte
zero32 []byte
)
func init() {
initVersion(version01HashString, &version01HashBytes)
initVersion(version02HashString, &version02HashBytes)
zero32 = make([]byte, 32)
}
func initVersion(hash string, bytes *[]byte) {
b, err := hex.DecodeString(hash)
if err != nil {
panic(err)
}
*bytes = make([]byte, versionHashSize)
copy(*bytes, b)
}
var (
// ErrTooShort signals too short input.
ErrTooShort = errors.New("serialised input too short")
// ErrInvalidInput signals invalid input to serialise.
ErrInvalidInput = errors.New("input invalid")
// ErrInvalidVersionHash signals unknown version of hash.
ErrInvalidVersionHash = errors.New("invalid version hash")
)
var obfuscationKeyFn = rand.Read
// SetObfuscationKeyFn allows configuring custom function for generating
// obfuscation key.
//
// NOTE: This should only be used in tests.
func SetObfuscationKeyFn(fn func([]byte) (int, error)) {
obfuscationKeyFn = fn
}
// MarshalBinary serialises the node
func (n *Node) MarshalBinary() (bytes []byte, err error) {
if n.forks == nil {
return nil, ErrInvalidInput
}
// header
headerBytes := make([]byte, nodeHeaderSize)
if len(n.obfuscationKey) == 0 {
// generate obfuscation key
obfuscationKey := make([]byte, nodeObfuscationKeySize)
for i := 0; i < nodeObfuscationKeySize; {
read, _ := obfuscationKeyFn(obfuscationKey[i:])
i += read
}
n.obfuscationKey = obfuscationKey
}
copy(headerBytes[0:nodeObfuscationKeySize], n.obfuscationKey)
copy(headerBytes[nodeObfuscationKeySize:nodeObfuscationKeySize+versionHashSize], version02HashBytes)
headerBytes[nodeObfuscationKeySize+versionHashSize] = uint8(n.refBytesSize)
bytes = append(bytes, headerBytes...)
// entry
entryBytes := make([]byte, n.refBytesSize)
copy(entryBytes, n.entry)
bytes = append(bytes, entryBytes...)
// index
indexBytes := make([]byte, 32)
var index = &bitsForBytes{}
for k := range n.forks {
index.set(k)
}
copy(indexBytes, index.bytes())
bytes = append(bytes, indexBytes...)
err = index.iter(func(b byte) error {
f := n.forks[b]
ref, err := f.bytes()
if err != nil {
return fmt.Errorf("%w on byte '%x'", err, []byte{b})
}
bytes = append(bytes, ref...)
return nil
})
if err != nil {
return nil, err
}
// perform XOR encryption on bytes after obfuscation key
xorEncryptedBytes := make([]byte, len(bytes))
copy(xorEncryptedBytes, bytes[0:nodeObfuscationKeySize])
for i := nodeObfuscationKeySize; i < len(bytes); i += nodeObfuscationKeySize {
end := i + nodeObfuscationKeySize
if end > len(bytes) {
end = len(bytes)
}
encrypted := encryptDecrypt(bytes[i:end], n.obfuscationKey)
copy(xorEncryptedBytes[i:end], encrypted)
}
return xorEncryptedBytes, nil
}
// bitsForBytes is a set of bytes represented as a 256-length bitvector
type bitsForBytes struct {
bits [32]byte
}
func (bb *bitsForBytes) bytes() (b []byte) {
b = append(b, bb.bits[:]...)
return b
}
func (bb *bitsForBytes) fromBytes(b []byte) {
copy(bb.bits[:], b)
}
func (bb *bitsForBytes) set(b byte) {
bb.bits[b/8] |= 1 << (b % 8)
}
//nolint,unused
func (bb *bitsForBytes) get(b byte) bool { // skipcq: SCC-U1000
return bb.getUint8(b)
}
func (bb *bitsForBytes) getUint8(i uint8) bool {
return (bb.bits[i/8]>>(i%8))&1 > 0
}
func (bb *bitsForBytes) iter(f func(byte) error) error {
for i := uint8(0); ; i++ {
if bb.getUint8(i) {
if err := f(i); err != nil {
return err
}
}
if i == 255 {
return nil
}
}
}
// UnmarshalBinary deserialises a node
func (n *Node) UnmarshalBinary(data []byte) error {
if len(data) < nodeHeaderSize {
return ErrTooShort
}
n.obfuscationKey = append([]byte{}, data[0:nodeObfuscationKeySize]...)
// perform XOR decryption on bytes after obfuscation key
xorDecryptedBytes := make([]byte, len(data))
copy(xorDecryptedBytes, data[0:nodeObfuscationKeySize])
for i := nodeObfuscationKeySize; i < len(data); i += nodeObfuscationKeySize {
end := i + nodeObfuscationKeySize
if end > len(data) {
end = len(data)
}
decrypted := encryptDecrypt(data[i:end], n.obfuscationKey)
copy(xorDecryptedBytes[i:end], decrypted)
}
data = xorDecryptedBytes
// Verify version hash.
versionHash := data[nodeObfuscationKeySize : nodeObfuscationKeySize+versionHashSize]
if bytes.Equal(versionHash, version01HashBytes) {
refBytesSize := int(data[nodeHeaderSize-1])
n.entry = append([]byte{}, data[nodeHeaderSize:nodeHeaderSize+refBytesSize]...)
offset := nodeHeaderSize + refBytesSize // skip entry
n.forks = make(map[byte]*fork)
bb := &bitsForBytes{}
bb.fromBytes(data[offset:])
offset += 32 // skip forks
return bb.iter(func(b byte) error {
f := &fork{}
if len(data) < offset+nodeForkPreReferenceSize+refBytesSize {
err := fmt.Errorf("not enough bytes for node fork: %d (%d)", (len(data) - offset), (nodeForkPreReferenceSize + refBytesSize))
return fmt.Errorf("%w on byte '%x'", err, []byte{b})
}
err := f.fromBytes(data[offset : offset+nodeForkPreReferenceSize+refBytesSize])
if err != nil {
return fmt.Errorf("%w on byte '%x'", err, []byte{b})
}
n.forks[b] = f
offset += nodeForkPreReferenceSize + refBytesSize
return nil
})
} else if bytes.Equal(versionHash, version02HashBytes) {
refBytesSize := int(data[nodeHeaderSize-1])
n.entry = append([]byte{}, data[nodeHeaderSize:nodeHeaderSize+refBytesSize]...)
offset := nodeHeaderSize + refBytesSize // skip entry
// Currently we don't persist the root nodeType when we marshal the manifest, as a result
// the root nodeType information is lost on Unmarshal. This causes issues when we want to
// perform a path 'Walk' on the root. If there is more than 1 fork, the root node type
// is an edge, so we will deduce this information from index byte array
if !bytes.Equal(data[offset:offset+32], zero32) && !n.IsEdgeType() {
n.makeEdge()
}
n.forks = make(map[byte]*fork)
bb := &bitsForBytes{}
bb.fromBytes(data[offset:])
offset += 32 // skip forks
return bb.iter(func(b byte) error {
f := &fork{}
if len(data) < offset+nodeForkTypeBytesSize {
return fmt.Errorf("not enough bytes for node fork: %d (%d) on byte '%x'", (len(data) - offset), (nodeForkTypeBytesSize), []byte{b})
}
nodeType := data[offset]
nodeForkSize := nodeForkPreReferenceSize + refBytesSize
if nodeTypeIsWithMetadataType(nodeType) {
if len(data) < offset+nodeForkPreReferenceSize+refBytesSize+nodeForkMetadataBytesSize {
return fmt.Errorf("not enough bytes for node fork: %d (%d) on byte '%x'", (len(data) - offset), (nodeForkPreReferenceSize + refBytesSize + nodeForkMetadataBytesSize), []byte{b})
}
metadataBytesSize := binary.BigEndian.Uint16(data[offset+nodeForkSize : offset+nodeForkSize+nodeForkMetadataBytesSize])
nodeForkSize += nodeForkMetadataBytesSize
nodeForkSize += int(metadataBytesSize)
err := f.fromBytes02(data[offset:offset+nodeForkSize], refBytesSize, int(metadataBytesSize))
if err != nil {
return fmt.Errorf("%w on byte '%x'", err, []byte{b})
}
} else {
if len(data) < offset+nodeForkPreReferenceSize+refBytesSize {
return fmt.Errorf("not enough bytes for node fork: %d (%d) on byte '%x'", (len(data) - offset), (nodeForkPreReferenceSize + refBytesSize), []byte{b})
}
err := f.fromBytes(data[offset : offset+nodeForkSize])
if err != nil {
return fmt.Errorf("%w on byte '%x'", err, []byte{b})
}
}
n.forks[b] = f
offset += nodeForkSize
return nil
})
}
return fmt.Errorf("%x: %w", versionHash, ErrInvalidVersionHash)
}
func (f *fork) fromBytes(b []byte) error {
nodeType := b[0]
prefixLen := int(b[1])
if prefixLen == 0 || prefixLen > nodePrefixMaxSize {
return fmt.Errorf("invalid prefix length: %d", prefixLen)
}
f.prefix = b[nodeForkHeaderSize : nodeForkHeaderSize+prefixLen]
f.Node = NewNodeRef(b[nodeForkPreReferenceSize:])
f.Node.nodeType = nodeType
return nil
}
func (f *fork) fromBytes02(b []byte, refBytesSize, metadataBytesSize int) error {
nodeType := b[0]
prefixLen := int(b[1])
if prefixLen == 0 || prefixLen > nodePrefixMaxSize {
return fmt.Errorf("invalid prefix length: %d", prefixLen)
}
f.prefix = b[nodeForkHeaderSize : nodeForkHeaderSize+prefixLen]
f.Node = NewNodeRef(b[nodeForkPreReferenceSize : nodeForkPreReferenceSize+refBytesSize])
f.Node.nodeType = nodeType
if metadataBytesSize > 0 {
metadataBytes := b[nodeForkPreReferenceSize+refBytesSize+nodeForkMetadataBytesSize:]
metadata := make(map[string]string)
// using JSON encoding for metadata
err := json.Unmarshal(metadataBytes, &metadata)
if err != nil {
return err
}
f.Node.metadata = metadata
}
return nil
}
func (f *fork) bytes() (b []byte, err error) {
r := refBytes(f)
// using 1 byte ('f.Node.refBytesSize') for size
if len(r) > 256 {
err = fmt.Errorf("node reference size > 256: %d", len(r))
return
}
b = append(b, f.Node.nodeType, uint8(len(f.prefix)))
prefixBytes := make([]byte, nodePrefixMaxSize)
copy(prefixBytes, f.prefix)
b = append(b, prefixBytes...)
refBytes := make([]byte, len(r))
copy(refBytes, r)
b = append(b, refBytes...)
if f.Node.IsWithMetadataType() {
// using JSON encoding for metadata
metadataJSONBytes, err1 := json.Marshal(f.Node.metadata)
if err1 != nil {
return b, err1
}
metadataJSONBytesSizeWithSize := len(metadataJSONBytes) + nodeForkMetadataBytesSize
// pad JSON bytes if necessary
if metadataJSONBytesSizeWithSize < nodeObfuscationKeySize {
paddingLength := nodeObfuscationKeySize - metadataJSONBytesSizeWithSize
padding := make([]byte, paddingLength)
for i := range padding {
padding[i] = '\n'
}
metadataJSONBytes = append(metadataJSONBytes, padding...)
} else if metadataJSONBytesSizeWithSize > nodeObfuscationKeySize {
paddingLength := nodeObfuscationKeySize - metadataJSONBytesSizeWithSize%nodeObfuscationKeySize
padding := make([]byte, paddingLength)
for i := range padding {
padding[i] = '\n'
}
metadataJSONBytes = append(metadataJSONBytes, padding...)
}
metadataJSONBytesSize := len(metadataJSONBytes)
if metadataJSONBytesSize > int(maxUint16) {
return b, ErrMetadataTooLarge
}
mBytesSize := make([]byte, nodeForkMetadataBytesSize)
binary.BigEndian.PutUint16(mBytesSize, uint16(metadataJSONBytesSize))
b = append(b, mBytesSize...)
b = append(b, metadataJSONBytes...)
}
return b, nil
}
var refBytes = nodeRefBytes
func nodeRefBytes(f *fork) []byte {
return f.Node.ref
}
// encryptDecrypt runs a XOR encryption on the input bytes, encrypting it if it
// hasn't already been, and decrypting it if it has, using the key provided.
func encryptDecrypt(input, key []byte) []byte {
output := make([]byte, len(input))
for i := 0; i < len(input); i++ {
output[i] = input[i] ^ key[i%len(key)]
}
return output
}