plugeth/core/vm/contracts.go
Péter Szilágyi 08eea0f0e4 accounts, core, crypto, internal: use normalised V during signature handling (#3455)
To address increasing complexity in code that handles signatures, this PR
discards all notion of "different" signature types at the library level. Both
the crypto and accounts package is reduced to only be able to produce plain
canonical secp256k1 signatures. This makes the crpyto APIs much cleaner,
simpler and harder to abuse.
2017-01-05 11:35:23 +01:00

114 lines
3.5 KiB
Go

// Copyright 2014 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 vm
import (
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
"github.com/ethereum/go-ethereum/params"
)
// PrecompiledAccount represents a native ethereum contract
type PrecompiledAccount struct {
Gas func(l int) *big.Int
fn func(in []byte) []byte
}
// Call calls the native function
func (self PrecompiledAccount) Call(in []byte) []byte {
return self.fn(in)
}
// Precompiled contains the default set of ethereum contracts
var Precompiled = PrecompiledContracts()
// PrecompiledContracts returns the default set of precompiled ethereum
// contracts defined by the ethereum yellow paper.
func PrecompiledContracts() map[string]*PrecompiledAccount {
return map[string]*PrecompiledAccount{
// ECRECOVER
string(common.LeftPadBytes([]byte{1}, 20)): &PrecompiledAccount{func(l int) *big.Int {
return params.EcrecoverGas
}, ecrecoverFunc},
// SHA256
string(common.LeftPadBytes([]byte{2}, 20)): &PrecompiledAccount{func(l int) *big.Int {
n := big.NewInt(int64(l+31) / 32)
n.Mul(n, params.Sha256WordGas)
return n.Add(n, params.Sha256Gas)
}, sha256Func},
// RIPEMD160
string(common.LeftPadBytes([]byte{3}, 20)): &PrecompiledAccount{func(l int) *big.Int {
n := big.NewInt(int64(l+31) / 32)
n.Mul(n, params.Ripemd160WordGas)
return n.Add(n, params.Ripemd160Gas)
}, ripemd160Func},
string(common.LeftPadBytes([]byte{4}, 20)): &PrecompiledAccount{func(l int) *big.Int {
n := big.NewInt(int64(l+31) / 32)
n.Mul(n, params.IdentityWordGas)
return n.Add(n, params.IdentityGas)
}, memCpy},
}
}
func sha256Func(in []byte) []byte {
return crypto.Sha256(in)
}
func ripemd160Func(in []byte) []byte {
return common.LeftPadBytes(crypto.Ripemd160(in), 32)
}
const ecRecoverInputLength = 128
func ecrecoverFunc(in []byte) []byte {
in = common.RightPadBytes(in, 128)
// "in" is (hash, v, r, s), each 32 bytes
// but for ecrecover we want (r, s, v)
r := common.BytesToBig(in[64:96])
s := common.BytesToBig(in[96:128])
v := in[63] - 27
// tighter sig s values in homestead only apply to tx sigs
if common.Bytes2Big(in[32:63]).BitLen() > 0 || !crypto.ValidateSignatureValues(v, r, s, false) {
glog.V(logger.Detail).Infof("ECRECOVER error: v, r or s value invalid")
return nil
}
// v needs to be at the end for libsecp256k1
pubKey, err := crypto.Ecrecover(in[:32], append(in[64:128], v))
// make sure the public key is a valid one
if err != nil {
glog.V(logger.Detail).Infoln("ECRECOVER error: ", err)
return nil
}
// the first byte of pubkey is bitcoin heritage
return common.LeftPadBytes(crypto.Keccak256(pubKey[1:])[12:], 32)
}
func memCpy(in []byte) []byte {
return in
}