120 lines
3.7 KiB
Go
120 lines
3.7 KiB
Go
// Copyright 2014 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package vm
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import (
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"math/big"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/crypto"
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"github.com/ethereum/go-ethereum/logger"
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"github.com/ethereum/go-ethereum/logger/glog"
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"github.com/ethereum/go-ethereum/params"
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)
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// PrecompiledAccount represents a native ethereum contract
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type PrecompiledAccount struct {
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Gas func(l int) *big.Int
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fn func(in []byte) []byte
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}
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// Call calls the native function
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func (self PrecompiledAccount) Call(in []byte) []byte {
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return self.fn(in)
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}
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// Precompiled contains the default set of ethereum contracts
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var Precompiled = PrecompiledContracts()
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// PrecompiledContracts returns the default set of precompiled ethereum
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// contracts defined by the ethereum yellow paper.
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func PrecompiledContracts() map[string]*PrecompiledAccount {
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return map[string]*PrecompiledAccount{
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// ECRECOVER
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string(common.LeftPadBytes([]byte{1}, 20)): &PrecompiledAccount{func(l int) *big.Int {
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return params.EcrecoverGas
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}, ecrecoverFunc},
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// SHA256
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string(common.LeftPadBytes([]byte{2}, 20)): &PrecompiledAccount{func(l int) *big.Int {
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n := big.NewInt(int64(l+31) / 32)
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n.Mul(n, params.Sha256WordGas)
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return n.Add(n, params.Sha256Gas)
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}, sha256Func},
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// RIPEMD160
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string(common.LeftPadBytes([]byte{3}, 20)): &PrecompiledAccount{func(l int) *big.Int {
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n := big.NewInt(int64(l+31) / 32)
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n.Mul(n, params.Ripemd160WordGas)
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return n.Add(n, params.Ripemd160Gas)
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}, ripemd160Func},
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string(common.LeftPadBytes([]byte{4}, 20)): &PrecompiledAccount{func(l int) *big.Int {
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n := big.NewInt(int64(l+31) / 32)
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n.Mul(n, params.IdentityWordGas)
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return n.Add(n, params.IdentityGas)
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}, memCpy},
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}
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}
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func sha256Func(in []byte) []byte {
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return crypto.Sha256(in)
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}
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func ripemd160Func(in []byte) []byte {
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return common.LeftPadBytes(crypto.Ripemd160(in), 32)
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}
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const ecRecoverInputLength = 128
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func ecrecoverFunc(in []byte) []byte {
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in = common.RightPadBytes(in, 128)
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// "in" is (hash, v, r, s), each 32 bytes
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// but for ecrecover we want (r, s, v)
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r := common.BytesToBig(in[64:96])
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s := common.BytesToBig(in[96:128])
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// Treat V as a 256bit integer
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vbig := common.Bytes2Big(in[32:64])
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v := byte(vbig.Uint64())
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// tighter sig s values in homestead only apply to tx sigs
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if !crypto.ValidateSignatureValues(v, r, s, false) {
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glog.V(logger.Debug).Infof("EC RECOVER FAIL: v, r or s value invalid")
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return nil
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}
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// v needs to be at the end and normalized for libsecp256k1
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vbignormal := new(big.Int).Sub(vbig, big.NewInt(27))
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vnormal := byte(vbignormal.Uint64())
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rsv := append(in[64:128], vnormal)
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pubKey, err := crypto.Ecrecover(in[:32], rsv)
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// make sure the public key is a valid one
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if err != nil {
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glog.V(logger.Error).Infof("EC RECOVER FAIL: ", err)
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return nil
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}
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// the first byte of pubkey is bitcoin heritage
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return common.LeftPadBytes(crypto.Keccak256(pubKey[1:])[12:], 32)
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}
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func memCpy(in []byte) []byte {
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return in
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}
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