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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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

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.

172
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())
}
}

81
ethclient/ethclient.go
View File

@ -20,6 +20,7 @@ package ethclient
import (
"context"
"encoding/json"
"errors"
"fmt"
"math/big"
@ -71,7 +72,7 @@ func (ec *Client) BlockByNumber(ctx context.Context, number *big.Int) (*types.Bl
type rpcBlock struct {
Hash common.Hash `json:"hash"`
Transactions []*types.Transaction `json:"transactions"`
Transactions []rpcTransaction `json:"transactions"`
UncleHashes []common.Hash `json:"uncles"`
}
@ -129,7 +130,13 @@ func (ec *Client) getBlock(ctx context.Context, method string, args ...interface
}
}
}
return types.NewBlockWithHeader(head).WithBody(body.Transactions, uncles), nil
// Fill the sender cache of transactions in the block.
txs := make([]*types.Transaction, len(body.Transactions))
for i, tx := range body.Transactions {
setSenderFromServer(tx.tx, tx.From, body.Hash)
txs[i] = tx.tx
}
return types.NewBlockWithHeader(head).WithBody(txs, uncles), nil
}
// HeaderByHash returns the block header with the given hash.
@ -153,25 +160,62 @@ func (ec *Client) HeaderByNumber(ctx context.Context, number *big.Int) (*types.H
return head, err
}
type rpcTransaction struct {
tx *types.Transaction
txExtraInfo
}
type txExtraInfo struct {
BlockNumber *string
BlockHash common.Hash
From common.Address
}
func (tx *rpcTransaction) UnmarshalJSON(msg []byte) error {
if err := json.Unmarshal(msg, &tx.tx); err != nil {
return err
}
return json.Unmarshal(msg, &tx.txExtraInfo)
}
// TransactionByHash returns the transaction with the given hash.
func (ec *Client) TransactionByHash(ctx context.Context, hash common.Hash) (tx *types.Transaction, isPending bool, err error) {
var raw json.RawMessage
err = ec.c.CallContext(ctx, &raw, "eth_getTransactionByHash", hash)
var json *rpcTransaction
err = ec.c.CallContext(ctx, &json, "eth_getTransactionByHash", hash)
if err != nil {
return nil, false, err
} else if len(raw) == 0 {
} else if json == nil {
return nil, false, ethereum.NotFound
}
if err := json.Unmarshal(raw, &tx); err != nil {
return nil, false, err
} else if _, r, _ := tx.RawSignatureValues(); r == nil {
} else if _, r, _ := json.tx.RawSignatureValues(); r == nil {
return nil, false, fmt.Errorf("server returned transaction without signature")
}
var block struct{ BlockNumber *string }
if err := json.Unmarshal(raw, &block); err != nil {
return nil, false, err
setSenderFromServer(json.tx, json.From, json.BlockHash)
return json.tx, json.BlockNumber == nil, nil
}
return tx, block.BlockNumber == nil, nil
// TransactionSender returns the sender address of the given transaction. The transaction
// must be known to the remote node and included in the blockchain at the given block and
// index. The sender is the one derived by the protocol at the time of inclusion.
//
// There is a fast-path for transactions retrieved by TransactionByHash and
// TransactionInBlock. Getting their sender address can be done without an RPC interaction.
func (ec *Client) TransactionSender(ctx context.Context, tx *types.Transaction, block common.Hash, index uint) (common.Address, error) {
// Try to load the address from the cache.
sender, err := types.Sender(&senderFromServer{blockhash: block}, tx)
if err == nil {
return sender, nil
}
var meta struct {
Hash common.Hash
From common.Address
}
if err = ec.c.CallContext(ctx, &meta, "eth_getTransactionByBlockHashAndIndex", block, hexutil.Uint64(index)); err != nil {
return common.Address{}, err
}
if meta.Hash == (common.Hash{}) || meta.Hash != tx.Hash() {
return common.Address{}, errors.New("wrong inclusion block/index")
}
return meta.From, nil
}
// TransactionCount returns the total number of transactions in the given block.
@ -183,16 +227,17 @@ func (ec *Client) TransactionCount(ctx context.Context, blockHash common.Hash) (
// TransactionInBlock returns a single transaction at index in the given block.
func (ec *Client) TransactionInBlock(ctx context.Context, blockHash common.Hash, index uint) (*types.Transaction, error) {
var tx *types.Transaction
err := ec.c.CallContext(ctx, &tx, "eth_getTransactionByBlockHashAndIndex", blockHash, hexutil.Uint64(index))
var json *rpcTransaction
err := ec.c.CallContext(ctx, &json, "eth_getTransactionByBlockHashAndIndex", blockHash, hexutil.Uint64(index))
if err == nil {
if tx == nil {
if json == nil {
return nil, ethereum.NotFound
} else if _, r, _ := tx.RawSignatureValues(); r == nil {
} else if _, r, _ := json.tx.RawSignatureValues(); r == nil {
return nil, fmt.Errorf("server returned transaction without signature")
}
}
return tx, err
setSenderFromServer(json.tx, json.From, json.BlockHash)
return json.tx, err
}
// TransactionReceipt returns the receipt of a transaction by transaction hash.

59
ethclient/signer.go Normal file
View File

@ -0,0 +1,59 @@
// Copyright 2017 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/>.
package ethclient
import (
"errors"
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
)
// senderFromServer is a types.Signer that remembers the sender address returned by the RPC
// server. It is stored in the transaction's sender address cache to avoid an additional
// request in TransactionSender.
type senderFromServer struct {
addr common.Address
blockhash common.Hash
}
var errNotCached = errors.New("sender not cached")
func setSenderFromServer(tx *types.Transaction, addr common.Address, block common.Hash) {
// Use types.Sender for side-effect to store our signer into the cache.
types.Sender(&senderFromServer{addr, block}, tx)
}
func (s *senderFromServer) Equal(other types.Signer) bool {
os, ok := other.(*senderFromServer)
return ok && os.blockhash == s.blockhash
}
func (s *senderFromServer) Sender(tx *types.Transaction) (common.Address, error) {
if s.blockhash == (common.Hash{}) {
return common.Address{}, errNotCached
}
return s.addr, nil
}
func (s *senderFromServer) Hash(tx *types.Transaction) common.Hash {
panic("can't sign with senderFromServer")
}
func (s *senderFromServer) SignatureValues(tx *types.Transaction, sig []byte) (R, S, V *big.Int, err error) {
panic("can't sign with senderFromServer")
}

7
mobile/ethclient.go
View File

@ -77,6 +77,13 @@ func (ec *EthereumClient) GetTransactionByHash(ctx *Context, hash *Hash) (tx *Tr
return &Transaction{rawTx}, err
}
// GetTransactionSender returns the sender address of a transaction. The transaction must
// be included in blockchain at the given block and index.
func (ec *EthereumClient) GetTransactionSender(ctx *Context, tx *Transaction, blockhash *Hash, index int) (sender *Address, _ error) {
addr, err := ec.client.TransactionSender(ctx.context, tx.tx, blockhash.hash, uint(index))
return &Address{addr}, err
}
// GetTransactionCount returns the total number of transactions in the given block.
func (ec *EthereumClient) GetTransactionCount(ctx *Context, hash *Hash) (count int, _ error) {
rawCount, err := ec.client.TransactionCount(ctx.context, hash.hash)

5
mobile/types.go
View File

@ -262,9 +262,12 @@ func (tx *Transaction) GetValue() *BigInt { return &BigInt{tx.tx.Value()} }
func (tx *Transaction) GetNonce() int64 { return int64(tx.tx.Nonce()) }
func (tx *Transaction) GetHash() *Hash { return &Hash{tx.tx.Hash()} }
func (tx *Transaction) GetSigHash() *Hash { return &Hash{tx.tx.SigHash(types.HomesteadSigner{})} }
func (tx *Transaction) GetCost() *BigInt { return &BigInt{tx.tx.Cost()} }
// Deprecated: GetSigHash cannot know which signer to use.
func (tx *Transaction) GetSigHash() *Hash { return &Hash{types.HomesteadSigner{}.Hash(tx.tx)} }
// Deprecated: use EthereumClient.TransactionSender
func (tx *Transaction) GetFrom(chainID *BigInt) (address *Address, _ error) {
var signer types.Signer = types.HomesteadSigner{}
if chainID != nil {