/
transaction_signing.go
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/
transaction_signing.go
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// Modifications Copyright 2018 The klaytn Authors
// Copyright 2015 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
//
// This file is derived from core/types/transaction_signing.go (2018/06/04).
// Modified and improved for the klaytn development.
package types
import (
"crypto/ecdsa"
"encoding/json"
"errors"
"fmt"
"github.com/klaytn/klaytn/blockchain/types/accountkey"
"github.com/klaytn/klaytn/common"
"github.com/klaytn/klaytn/crypto"
"github.com/klaytn/klaytn/params"
"math/big"
)
var (
ErrInvalidChainId = errors.New("invalid chain id for signer")
errNotTxInternalDataFrom = errors.New("not an TxInternalDataFrom")
)
// sigCache is used to cache the derived sender and contains
// the signer used to derive it.
type sigCache struct {
signer Signer
from common.Address
}
// sigCachePubkey is used to cache the derived public key and contains
// the signer used to derive it.
type sigCachePubkey struct {
signer Signer
pubkey []*ecdsa.PublicKey
}
// TODO-Klaytn-RemoveLater Remove the second parameter blockNumber
// MakeSigner returns a Signer based on the given chain config and block number.
func MakeSigner(config *params.ChainConfig, blockNumber *big.Int) Signer {
return NewEIP155Signer(config.ChainID)
}
// SignTx signs the transaction using the given signer and private key
func SignTx(tx *Transaction, s Signer, prv *ecdsa.PrivateKey) (*Transaction, error) {
h := s.Hash(tx)
sig, err := crypto.Sign(h[:], prv)
if err != nil {
return nil, err
}
return tx.WithSignature(s, sig)
}
// AccountKeyPicker has a function GetKey() to retrieve an account key from statedb.
type AccountKeyPicker interface {
GetKey(address common.Address) accountkey.AccountKey
Exist(addr common.Address) bool
}
// Sender returns the address of the transaction.
// If a legacy transaction, it calls SenderFrom().
// Otherwise, it just returns tx.From() because the other transaction types have the field `from`.
// NOTE: this function should not be called if tx signature validation is required.
// In that situtation, you should call ValidateSender().
func Sender(signer Signer, tx *Transaction) (common.Address, error) {
if tx.IsLegacyTransaction() {
return SenderFrom(signer, tx)
}
return tx.From()
}
// SenderFeePayer returns the fee payer address of the transaction.
// If the transaction is not a fee-delegated transaction, the fee payer is set to
// the address of the `from` of the transaction.
func SenderFeePayer(signer Signer, tx *Transaction) (common.Address, error) {
tf, ok := tx.data.(TxInternalDataFeePayer)
if !ok {
return Sender(signer, tx)
}
return tf.GetFeePayer(), nil
}
// SenderFeePayerPubkey returns the public key derived from the signature (V, R, S) using secp256k1
// elliptic curve and an error if it failed deriving or upon an incorrect
// signature.
//
// SenderFeePayerPubkey may cache the public key, allowing it to be used regardless of
// signing method. The cache is invalidated if the cached signer does
// not match the signer used in the current call.
func SenderFeePayerPubkey(signer Signer, tx *Transaction) ([]*ecdsa.PublicKey, error) {
if sc := tx.feePayer.Load(); sc != nil {
sigCache := sc.(sigCachePubkey)
// If the signer used to derive from in a previous
// call is not the same as used current, invalidate
// the cache.
if sigCache.signer.Equal(signer) {
return sigCache.pubkey, nil
}
}
pubkey, err := signer.SenderFeePayer(tx)
if err != nil {
return nil, err
}
tx.feePayer.Store(sigCachePubkey{signer: signer, pubkey: pubkey})
return pubkey, nil
}
// SenderFrom returns the address derived from the signature (V, R, S) using secp256k1
// elliptic curve and an error if it failed deriving or upon an incorrect
// signature.
//
// SenderFrom may cache the address, allowing it to be used regardless of
// signing method. The cache is invalidated if the cached signer does
// not match the signer used in the current call.
func SenderFrom(signer Signer, tx *Transaction) (common.Address, error) {
if sc := tx.from.Load(); sc != nil {
sigCache := sc.(sigCache)
// If the signer used to derive from in a previous
// call is not the same as used current, invalidate
// the cache.
if sigCache.signer.Equal(signer) {
return sigCache.from, nil
}
}
addr, err := signer.Sender(tx)
if err != nil {
return common.Address{}, err
}
tx.from.Store(sigCache{signer: signer, from: addr})
return addr, nil
}
// SenderPubkey returns the public key derived from the signature (V, R, S) using secp256k1
// elliptic curve and an error if it failed deriving or upon an incorrect
// signature.
//
// SenderPubkey may cache the public key, allowing it to be used regardless of
// signing method. The cache is invalidated if the cached signer does
// not match the signer used in the current call.
func SenderPubkey(signer Signer, tx *Transaction) ([]*ecdsa.PublicKey, error) {
if sc := tx.from.Load(); sc != nil {
sigCache := sc.(sigCachePubkey)
// If the signer used to derive from in a previous
// call is not the same as used current, invalidate
// the cache.
if sigCache.signer.Equal(signer) {
return sigCache.pubkey, nil
}
}
pubkey, err := signer.SenderPubkey(tx)
if err != nil {
return nil, err
}
tx.from.Store(sigCachePubkey{signer: signer, pubkey: pubkey})
return pubkey, nil
}
// Signer encapsulates transaction signature handling. Note that this interface is not a
// stable API and may change at any time to accommodate new protocol rules.
type Signer interface {
// Sender returns the sender address of the transaction.
Sender(tx *Transaction) (common.Address, error)
// SenderPubkey returns the public key derived from tx signature and txhash.
SenderPubkey(tx *Transaction) ([]*ecdsa.PublicKey, error)
// SenderFeePayer returns the public key derived from tx signature and txhash.
SenderFeePayer(tx *Transaction) ([]*ecdsa.PublicKey, error)
// SignatureValues returns the raw R, S, V values corresponding to the
// given signature.
SignatureValues(sig []byte) (r, s, v *big.Int, err error)
// Hash returns the hash to be signed.
Hash(tx *Transaction) common.Hash
// HashFeePayer returns the hash with a fee payer's address to be signed by a fee payer.
HashFeePayer(tx *Transaction) (common.Hash, error)
// Equal returns true if the given signer is the same as the receiver.
Equal(Signer) bool
}
// EIP155Transaction implements Signer using the EIP155 rules.
type EIP155Signer struct {
chainId, chainIdMul *big.Int
}
func NewEIP155Signer(chainId *big.Int) EIP155Signer {
if chainId == nil {
chainId = new(big.Int)
}
return EIP155Signer{
chainId: chainId,
chainIdMul: new(big.Int).Mul(chainId, common.Big2),
}
}
func (s EIP155Signer) Equal(s2 Signer) bool {
eip155, ok := s2.(EIP155Signer)
return ok && eip155.chainId.Cmp(s.chainId) == 0
}
var big8 = big.NewInt(8)
func (s EIP155Signer) Sender(tx *Transaction) (common.Address, error) {
if !tx.IsLegacyTransaction() {
b, _ := json.Marshal(tx)
logger.Warn("No need to execute Sender!", "tx", string(b))
}
if tx.ChainId().Cmp(s.chainId) != 0 {
return common.Address{}, ErrInvalidChainId
}
return tx.data.RecoverAddress(s.Hash(tx), true, func(v *big.Int) *big.Int {
V := new(big.Int).Sub(v, s.chainIdMul)
return V.Sub(V, big8)
})
}
func (s EIP155Signer) SenderPubkey(tx *Transaction) ([]*ecdsa.PublicKey, error) {
if tx.IsLegacyTransaction() {
b, _ := json.Marshal(tx)
logger.Warn("No need to execute SenderPubkey!", "tx", string(b))
}
if tx.ChainId().Cmp(s.chainId) != 0 {
return nil, ErrInvalidChainId
}
return tx.data.RecoverPubkey(s.Hash(tx), true, func(v *big.Int) *big.Int {
V := new(big.Int).Sub(v, s.chainIdMul)
return V.Sub(V, big8)
})
}
func (s EIP155Signer) SenderFeePayer(tx *Transaction) ([]*ecdsa.PublicKey, error) {
if tx.IsLegacyTransaction() {
b, _ := json.Marshal(tx)
logger.Warn("No need to execute SenderFeePayer!", "tx", string(b))
}
if tx.ChainId().Cmp(s.chainId) != 0 {
return nil, ErrInvalidChainId
}
tf, ok := tx.data.(TxInternalDataFeePayer)
if !ok {
return nil, errNotFeePayer
}
hash, err := s.HashFeePayer(tx)
if err != nil {
return nil, err
}
return tf.RecoverFeePayerPubkey(hash, true, func(v *big.Int) *big.Int {
V := new(big.Int).Sub(v, s.chainIdMul)
return V.Sub(V, big8)
})
}
// WithSignature returns a new transaction with the given signature. This signature
// needs to be in the [R || S || V] format where V is 0 or 1.
func (s EIP155Signer) SignatureValues(sig []byte) (R, S, V *big.Int, err error) {
if len(sig) != 65 {
panic(fmt.Sprintf("wrong size for signature: got %d, want 65", len(sig)))
}
R = new(big.Int).SetBytes(sig[:32])
S = new(big.Int).SetBytes(sig[32:64])
V = big.NewInt(int64(sig[64] + 35))
V.Add(V, s.chainIdMul)
return R, S, V, nil
}
// Hash returns the hash to be signed by the sender.
// It does not uniquely identify the transaction.
func (s EIP155Signer) Hash(tx *Transaction) common.Hash {
// If the data object implements SerializeForSignToByte(), use it.
if ser, ok := tx.data.(TxInternalDataSerializeForSignToByte); ok {
return rlpHash(struct {
Byte []byte
ChainId *big.Int
R uint
S uint
}{
ser.SerializeForSignToBytes(),
s.chainId,
uint(0),
uint(0),
})
}
infs := append(tx.data.SerializeForSign(),
s.chainId, uint(0), uint(0))
return rlpHash(infs)
}
// HashFeePayer returns the hash with a fee payer's address to be signed by a fee payer.
// It does not uniquely identify the transaction.
func (s EIP155Signer) HashFeePayer(tx *Transaction) (common.Hash, error) {
tf, ok := tx.data.(TxInternalDataFeePayer)
if !ok {
return common.Hash{}, errNotFeePayer
}
// If the data object implements SerializeForSignToByte(), use it.
if ser, ok := tx.data.(TxInternalDataSerializeForSignToByte); ok {
return rlpHash(struct {
Byte []byte
FeePayer common.Address
ChainId *big.Int
R uint
S uint
}{
ser.SerializeForSignToBytes(),
tf.GetFeePayer(),
s.chainId,
uint(0),
uint(0),
}), nil
}
infs := append(tx.data.SerializeForSign(),
tf.GetFeePayer(),
s.chainId, uint(0), uint(0))
return rlpHash(infs), nil
}
func recoverPlainCommon(sighash common.Hash, R, S, Vb *big.Int, homestead bool) ([]byte, error) {
if Vb.BitLen() > 8 {
return []byte{}, ErrInvalidSig
}
V := byte(Vb.Uint64() - 27)
if !crypto.ValidateSignatureValues(V, R, S, homestead) {
return []byte{}, ErrInvalidSig
}
// encode the snature in uncompressed format
r, s := R.Bytes(), S.Bytes()
sig := make([]byte, 65)
copy(sig[32-len(r):32], r)
copy(sig[64-len(s):64], s)
sig[64] = V
// recover the public key from the snature
pub, err := crypto.Ecrecover(sighash[:], sig)
if err != nil {
return []byte{}, err
}
if len(pub) == 0 || pub[0] != 4 {
return []byte{}, errors.New("invalid public key")
}
return pub, nil
}
func recoverPlain(sighash common.Hash, R, S, Vb *big.Int, homestead bool) (common.Address, error) {
pub, err := recoverPlainCommon(sighash, R, S, Vb, homestead)
if err != nil {
return common.Address{}, err
}
var addr common.Address
copy(addr[:], crypto.Keccak256(pub[1:])[12:])
return addr, nil
}
func recoverPlainPubkey(sighash common.Hash, R, S, Vb *big.Int, homestead bool) (*ecdsa.PublicKey, error) {
pub, err := recoverPlainCommon(sighash, R, S, Vb, homestead)
if err != nil {
return nil, err
}
pubkey, err := crypto.UnmarshalPubkey(pub)
if err != nil {
return nil, err
}
return pubkey, nil
}
// deriveChainId derives the chain id from the given v parameter
func deriveChainId(v *big.Int) *big.Int {
if v.BitLen() <= 64 {
v := v.Uint64()
if v == 27 || v == 28 {
return new(big.Int)
}
return new(big.Int).SetUint64((v - 35) / 2)
}
v = new(big.Int).Sub(v, big.NewInt(35))
return v.Div(v, common.Big2)
}