8b57c49490
Reworked the EVM gas instructions to use 64bit integers rather than arbitrary size big ints. All gas operations, be it additions, multiplications or divisions, are checked and guarded against 64 bit integer overflows. In additon, most of the protocol paramaters in the params package have been converted to uint64 and are now constants rather than variables. * common/math: added overflow check ops * core: vmenv, env renamed to evm * eth, internal/ethapi, les: unmetered eth_call and cancel methods * core/vm: implemented big.Int pool for evm instructions * core/vm: unexported intPool methods & verification methods * core/vm: added memoryGasCost overflow check and test
131 lines
4.6 KiB
Go
131 lines
4.6 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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"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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// Precompiled contract is the basic interface for native Go contracts. The implementation
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// requires a deterministic gas count based on the input size of the Run method of the
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// contract.
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type PrecompiledContract interface {
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RequiredGas(inputSize int) uint64 // RequiredPrice calculates the contract gas use
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Run(input []byte) []byte // Run runs the precompiled contract
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}
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// Precompiled contains the default set of ethereum contracts
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var PrecompiledContracts = map[common.Address]PrecompiledContract{
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common.BytesToAddress([]byte{1}): &ecrecover{},
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common.BytesToAddress([]byte{2}): &sha256{},
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common.BytesToAddress([]byte{3}): &ripemd160{},
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common.BytesToAddress([]byte{4}): &dataCopy{},
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}
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// RunPrecompile runs and evaluate the output of a precompiled contract defined in contracts.go
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func RunPrecompiledContract(p PrecompiledContract, input []byte, contract *Contract) (ret []byte, err error) {
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gas := p.RequiredGas(len(input))
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if contract.UseGas(gas) {
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ret = p.Run(input)
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return ret, nil
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} else {
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return nil, ErrOutOfGas
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}
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}
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// ECRECOVER implemented as a native contract
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type ecrecover struct{}
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func (c *ecrecover) RequiredGas(inputSize int) uint64 {
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return params.EcrecoverGas
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}
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func (c *ecrecover) Run(in []byte) []byte {
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const ecRecoverInputLength = 128
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in = common.RightPadBytes(in, ecRecoverInputLength)
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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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v := in[63] - 27
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// tighter sig s values in homestead only apply to tx sigs
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if common.Bytes2Big(in[32:63]).BitLen() > 0 || !crypto.ValidateSignatureValues(v, r, s, false) {
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glog.V(logger.Detail).Infof("ECRECOVER error: 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 for libsecp256k1
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pubKey, err := crypto.Ecrecover(in[:32], append(in[64:128], v))
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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.Detail).Infoln("ECRECOVER error: ", 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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// SHA256 implemented as a native contract
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type sha256 struct{}
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// RequiredGas returns the gas required to execute the pre-compiled contract.
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//
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// This method does not require any overflow checking as the input size gas costs
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// required for anything significant is so high it's impossible to pay for.
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func (c *sha256) RequiredGas(inputSize int) uint64 {
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return uint64(inputSize+31)/32*params.Sha256WordGas + params.Sha256Gas
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}
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func (c *sha256) Run(in []byte) []byte {
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return crypto.Sha256(in)
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}
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// RIPMED160 implemented as a native contract
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type ripemd160 struct{}
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// RequiredGas returns the gas required to execute the pre-compiled contract.
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//
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// This method does not require any overflow checking as the input size gas costs
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// required for anything significant is so high it's impossible to pay for.
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func (c *ripemd160) RequiredGas(inputSize int) uint64 {
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return uint64(inputSize+31)/32*params.Ripemd160WordGas + params.Ripemd160Gas
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}
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func (c *ripemd160) Run(in []byte) []byte {
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return common.LeftPadBytes(crypto.Ripemd160(in), 32)
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}
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// data copy implemented as a native contract
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type dataCopy struct{}
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// RequiredGas returns the gas required to execute the pre-compiled contract.
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//
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// This method does not require any overflow checking as the input size gas costs
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// required for anything significant is so high it's impossible to pay for.
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func (c *dataCopy) RequiredGas(inputSize int) uint64 {
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return uint64(inputSize+31)/32*params.IdentityWordGas + params.IdentityGas
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}
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func (c *dataCopy) Run(in []byte) []byte {
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return in
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}
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