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ethclient, mobile: add TransactionSender (#15127)

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* core/types: make Signer derive address instead of public key

There are two reasons to do this now: The upcoming ethclient signer
doesn't know the public key, just the address. EIP 208 will introduce a
new signer which derives the 'entry point' address for transactions with
zero signature. The entry point has no public key.

Other changes to the interface ease the path make to moving signature
crypto out of core/types later.

* ethclient, mobile: add TransactionSender

The new method can get the right signer without any crypto, and without
knowledge of the signature scheme that was used when the transaction was
included.
This commit is contained in:
Felix Lange
2017-10-01 11:03:28 +02:00
committed by GitHub
parent a660685746
commit d78ad226c2
7 changed files with 204 additions and 149 deletions
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14
core/types/transaction.go
View File

@ -209,12 +209,6 @@ func (tx *Transaction) Hash() common.Hash {
return v
}
// SigHash returns the hash to be signed by the sender.
// It does not uniquely identify the transaction.
func (tx *Transaction) SigHash(signer Signer) common.Hash {
return signer.Hash(tx)
}
func (tx *Transaction) Size() common.StorageSize {
if size := tx.size.Load(); size != nil {
return size.(common.StorageSize)
@ -249,7 +243,13 @@ func (tx *Transaction) AsMessage(s Signer) (Message, error) {
// WithSignature returns a new transaction with the given signature.
// This signature needs to be formatted as described in the yellow paper (v+27).
func (tx *Transaction) WithSignature(signer Signer, sig []byte) (*Transaction, error) {
return signer.WithSignature(tx, sig)
r, s, v, err := signer.SignatureValues(tx, sig)
if err != nil {
return nil, err
}
cpy := &Transaction{data: tx.data}
cpy.data.R, cpy.data.S, cpy.data.V = r, s, v
return cpy, nil
}
// Cost returns amount + gasprice * gaslimit.

174
core/types/transaction_signing.go
View File

@ -29,9 +29,6 @@ import (
var (
ErrInvalidChainId = errors.New("invalid chain id for signer")
errAbstractSigner = errors.New("abstract signer")
abstractSignerAddress = common.HexToAddress("ffffffffffffffffffffffffffffffffffffffff")
)
// sigCache is used to cache the derived sender and contains
@ -62,12 +59,9 @@ func SignTx(tx *Transaction, s Signer, prv *ecdsa.PrivateKey) (*Transaction, err
if err != nil {
return nil, err
}
return s.WithSignature(tx, sig)
return tx.WithSignature(s, sig)
}
// Sender derives the sender from the tx using the signer derivation
// functions.
// Sender 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.
@ -86,33 +80,30 @@ func Sender(signer Signer, tx *Transaction) (common.Address, error) {
}
}
pubkey, err := signer.PublicKey(tx)
addr, err := signer.Sender(tx)
if err != nil {
return common.Address{}, err
}
var addr common.Address
copy(addr[:], crypto.Keccak256(pubkey[1:])[12:])
tx.from.Store(sigCache{signer: signer, from: addr})
return addr, 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 {
// Hash returns the rlp encoded hash for signatures
// Sender returns the sender address of the transaction.
Sender(tx *Transaction) (common.Address, error)
// SignatureValues returns the raw R, S, V values corresponding to the
// given signature.
SignatureValues(tx *Transaction, sig []byte) (r, s, v *big.Int, err error)
// Hash returns the hash to be signed.
Hash(tx *Transaction) common.Hash
// PubilcKey returns the public key derived from the signature
PublicKey(tx *Transaction) ([]byte, error)
// WithSignature returns a copy of the transaction with the given signature.
// The signature must be encoded in [R || S || V] format where V is 0 or 1.
WithSignature(tx *Transaction, sig []byte) (*Transaction, error)
// Checks for equality on the signers
// Equal returns true if the given signer is the same as the receiver.
Equal(Signer) bool
}
// EIP155Transaction implements TransactionInterface using the
// EIP155 rules
// EIP155Transaction implements Signer using the EIP155 rules.
type EIP155Signer struct {
HomesteadSigner
chainId, chainIdMul *big.Int
}
@ -131,55 +122,32 @@ func (s EIP155Signer) Equal(s2 Signer) bool {
return ok && eip155.chainId.Cmp(s.chainId) == 0
}
func (s EIP155Signer) PublicKey(tx *Transaction) ([]byte, error) {
// if the transaction is not protected fall back to homestead signer
var big8 = big.NewInt(8)
func (s EIP155Signer) Sender(tx *Transaction) (common.Address, error) {
if !tx.Protected() {
return (HomesteadSigner{}).PublicKey(tx)
return HomesteadSigner{}.Sender(tx)
}
if tx.ChainId().Cmp(s.chainId) != 0 {
return nil, ErrInvalidChainId
return common.Address{}, ErrInvalidChainId
}
V := byte(new(big.Int).Sub(tx.data.V, s.chainIdMul).Uint64() - 35)
if !crypto.ValidateSignatureValues(V, tx.data.R, tx.data.S, true) {
return nil, ErrInvalidSig
}
// encode the signature in uncompressed format
R, S := tx.data.R.Bytes(), tx.data.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 signature
hash := s.Hash(tx)
pub, err := crypto.Ecrecover(hash[:], sig)
if err != nil {
return nil, err
}
if len(pub) == 0 || pub[0] != 4 {
return nil, errors.New("invalid public key")
}
return pub, nil
V := new(big.Int).Sub(tx.data.V, s.chainIdMul)
V.Sub(V, big8)
return recoverPlain(s.Hash(tx), tx.data.R, tx.data.S, V, true)
}
// 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) WithSignature(tx *Transaction, sig []byte) (*Transaction, error) {
if len(sig) != 65 {
panic(fmt.Sprintf("wrong size for signature: got %d, want 65", len(sig)))
func (s EIP155Signer) SignatureValues(tx *Transaction, sig []byte) (R, S, V *big.Int, err error) {
R, S, V, err = HomesteadSigner{}.SignatureValues(tx, sig)
if err != nil {
return nil, nil, nil, err
}
cpy := &Transaction{data: tx.data}
cpy.data.R = new(big.Int).SetBytes(sig[:32])
cpy.data.S = new(big.Int).SetBytes(sig[32:64])
cpy.data.V = new(big.Int).SetBytes([]byte{sig[64]})
if s.chainId.Sign() != 0 {
cpy.data.V = big.NewInt(int64(sig[64] + 35))
cpy.data.V.Add(cpy.data.V, s.chainIdMul)
V = big.NewInt(int64(sig[64] + 35))
V.Add(V, s.chainIdMul)
}
return cpy, nil
return R, S, V, nil
}
// Hash returns the hash to be signed by the sender.
@ -205,44 +173,14 @@ func (s HomesteadSigner) Equal(s2 Signer) bool {
return ok
}
// WithSignature returns a new transaction with the given signature. This signature
// SignatureValues returns signature values. This signature
// needs to be in the [R || S || V] format where V is 0 or 1.
func (hs HomesteadSigner) WithSignature(tx *Transaction, sig []byte) (*Transaction, error) {
if len(sig) != 65 {
panic(fmt.Sprintf("wrong size for snature: got %d, want 65", len(sig)))
}
cpy := &Transaction{data: tx.data}
cpy.data.R = new(big.Int).SetBytes(sig[:32])
cpy.data.S = new(big.Int).SetBytes(sig[32:64])
cpy.data.V = new(big.Int).SetBytes([]byte{sig[64] + 27})
return cpy, nil
func (hs HomesteadSigner) SignatureValues(tx *Transaction, sig []byte) (r, s, v *big.Int, err error) {
return hs.FrontierSigner.SignatureValues(tx, sig)
}
func (hs HomesteadSigner) PublicKey(tx *Transaction) ([]byte, error) {
if tx.data.V.BitLen() > 8 {
return nil, ErrInvalidSig
}
V := byte(tx.data.V.Uint64() - 27)
if !crypto.ValidateSignatureValues(V, tx.data.R, tx.data.S, true) {
return nil, ErrInvalidSig
}
// encode the snature in uncompressed format
r, s := tx.data.R.Bytes(), tx.data.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
hash := hs.Hash(tx)
pub, err := crypto.Ecrecover(hash[:], sig)
if err != nil {
return nil, err
}
if len(pub) == 0 || pub[0] != 4 {
return nil, errors.New("invalid public key")
}
return pub, nil
func (hs HomesteadSigner) Sender(tx *Transaction) (common.Address, error) {
return recoverPlain(hs.Hash(tx), tx.data.R, tx.data.S, tx.data.V, true)
}
type FrontierSigner struct{}
@ -252,20 +190,19 @@ func (s FrontierSigner) Equal(s2 Signer) bool {
return ok
}
// WithSignature returns a new transaction with the given signature. This signature
// SignatureValues returns signature values. This signature
// needs to be in the [R || S || V] format where V is 0 or 1.
func (fs FrontierSigner) WithSignature(tx *Transaction, sig []byte) (*Transaction, error) {
func (fs FrontierSigner) SignatureValues(tx *Transaction, sig []byte) (r, s, v *big.Int, err error) {
if len(sig) != 65 {
panic(fmt.Sprintf("wrong size for snature: got %d, want 65", len(sig)))
panic(fmt.Sprintf("wrong size for signature: got %d, want 65", len(sig)))
}
cpy := &Transaction{data: tx.data}
cpy.data.R = new(big.Int).SetBytes(sig[:32])
cpy.data.S = new(big.Int).SetBytes(sig[32:64])
cpy.data.V = new(big.Int).SetBytes([]byte{sig[64] + 27})
return cpy, nil
r = new(big.Int).SetBytes(sig[:32])
s = new(big.Int).SetBytes(sig[32:64])
v = new(big.Int).SetBytes([]byte{sig[64] + 27})
return r, s, v, nil
}
// Hash returns the hash to be sned by the sender.
// Hash returns the hash to be signed by the sender.
// It does not uniquely identify the transaction.
func (fs FrontierSigner) Hash(tx *Transaction) common.Hash {
return rlpHash([]interface{}{
@ -278,32 +215,35 @@ func (fs FrontierSigner) Hash(tx *Transaction) common.Hash {
})
}
func (fs FrontierSigner) PublicKey(tx *Transaction) ([]byte, error) {
if tx.data.V.BitLen() > 8 {
return nil, ErrInvalidSig
}
func (fs FrontierSigner) Sender(tx *Transaction) (common.Address, error) {
return recoverPlain(fs.Hash(tx), tx.data.R, tx.data.S, tx.data.V, false)
}
V := byte(tx.data.V.Uint64() - 27)
if !crypto.ValidateSignatureValues(V, tx.data.R, tx.data.S, false) {
return nil, ErrInvalidSig
func recoverPlain(sighash common.Hash, R, S, Vb *big.Int, homestead bool) (common.Address, error) {
if Vb.BitLen() > 8 {
return common.Address{}, ErrInvalidSig
}
V := byte(Vb.Uint64() - 27)
if !crypto.ValidateSignatureValues(V, R, S, homestead) {
return common.Address{}, ErrInvalidSig
}
// encode the snature in uncompressed format
r, s := tx.data.R.Bytes(), tx.data.S.Bytes()
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
hash := fs.Hash(tx)
pub, err := crypto.Ecrecover(hash[:], sig)
pub, err := crypto.Ecrecover(sighash[:], sig)
if err != nil {
return nil, err
return common.Address{}, err
}
if len(pub) == 0 || pub[0] != 4 {
return nil, errors.New("invalid public key")
return common.Address{}, errors.New("invalid public key")
}
return pub, nil
var addr common.Address
copy(addr[:], crypto.Keccak256(pub[1:])[12:])
return addr, nil
}
// deriveChainId derives the chain id from the given v parameter

5
core/types/transaction_test.go
View File

@ -52,10 +52,11 @@ var (
)
func TestTransactionSigHash(t *testing.T) {
if emptyTx.SigHash(HomesteadSigner{}) != common.HexToHash("c775b99e7ad12f50d819fcd602390467e28141316969f4b57f0626f74fe3b386") {
var homestead HomesteadSigner
if homestead.Hash(emptyTx) != common.HexToHash("c775b99e7ad12f50d819fcd602390467e28141316969f4b57f0626f74fe3b386") {
t.Errorf("empty transaction hash mismatch, got %x", emptyTx.Hash())
}
if rightvrsTx.SigHash(HomesteadSigner{}) != common.HexToHash("fe7a79529ed5f7c3375d06b26b186a8644e0e16c373d7a12be41c62d6042b77a") {
if homestead.Hash(rightvrsTx) != common.HexToHash("fe7a79529ed5f7c3375d06b26b186a8644e0e16c373d7a12be41c62d6042b77a") {
t.Errorf("RightVRS transaction hash mismatch, got %x", rightvrsTx.Hash())
}
}