erigon-pulse/core/vm/contracts.go
Felix Lange 5c8fe28b72 common: move big integer math to common/math (#3699)
* common: remove CurrencyToString

Move denomination values to params instead.

* common: delete dead code

* common: move big integer operations to common/math

This commit consolidates all big integer operations into common/math and
adds tests and documentation.

There should be no change in semantics for BigPow, BigMin, BigMax, S256,
U256, Exp and their behaviour is now locked in by tests.

The BigD, BytesToBig and Bytes2Big functions don't provide additional
value, all uses are replaced by new(big.Int).SetBytes().

BigToBytes is now called PaddedBigBytes, its minimum output size
parameter is now specified as the number of bytes instead of bits. The
single use of this function is in the EVM's MSTORE instruction.

Big and String2Big are replaced by ParseBig, which is slightly stricter.
It previously accepted leading zeros for hexadecimal inputs but treated
decimal inputs as octal if a leading zero digit was present.

ParseUint64 is used in places where String2Big was used to decode a
uint64.

The new functions MustParseBig and MustParseUint64 are now used in many
places where parsing errors were previously ignored.

* common: delete unused big integer variables

* accounts/abi: replace uses of BytesToBig with use of encoding/binary

* common: remove BytesToBig

* common: remove Bytes2Big

* common: remove BigTrue

* cmd/utils: add BigFlag and use it for error-checked integer flags

While here, remove environment variable processing for DirectoryFlag
because we don't use it.

* core: add missing error checks in genesis block parser

* common: remove String2Big

* cmd/evm: use utils.BigFlag

* common/math: check for 256 bit overflow in ParseBig

This is supposed to prevent silent overflow/truncation of values in the
genesis block JSON. Without this check, a genesis block that set a
balance larger than 256 bits would lead to weird behaviour in the VM.

* cmd/utils: fixup import
2017-02-26 22:21:51 +01:00

138 lines
4.7 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 (
"crypto/sha256"
"fmt"
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/params"
"golang.org/x/crypto/ripemd160"
)
// Precompiled contract is the basic interface for native Go contracts. The implementation
// requires a deterministic gas count based on the input size of the Run method of the
// contract.
type PrecompiledContract interface {
RequiredGas(inputSize int) uint64 // RequiredPrice calculates the contract gas use
Run(input []byte) []byte // Run runs the precompiled contract
}
// Precompiled contains the default set of ethereum contracts
var PrecompiledContracts = map[common.Address]PrecompiledContract{
common.BytesToAddress([]byte{1}): &ecrecover{},
common.BytesToAddress([]byte{2}): &sha256hash{},
common.BytesToAddress([]byte{3}): &ripemd160hash{},
common.BytesToAddress([]byte{4}): &dataCopy{},
}
// RunPrecompile runs and evaluate the output of a precompiled contract defined in contracts.go
func RunPrecompiledContract(p PrecompiledContract, input []byte, contract *Contract) (ret []byte, err error) {
gas := p.RequiredGas(len(input))
if contract.UseGas(gas) {
ret = p.Run(input)
return ret, nil
} else {
return nil, ErrOutOfGas
}
}
// ECRECOVER implemented as a native contract
type ecrecover struct{}
func (c *ecrecover) RequiredGas(inputSize int) uint64 {
return params.EcrecoverGas
}
func (c *ecrecover) Run(in []byte) []byte {
const ecRecoverInputLength = 128
in = common.RightPadBytes(in, ecRecoverInputLength)
// "in" is (hash, v, r, s), each 32 bytes
// but for ecrecover we want (r, s, v)
r := new(big.Int).SetBytes(in[64:96])
s := new(big.Int).SetBytes(in[96:128])
v := in[63] - 27
// tighter sig s values in homestead only apply to tx sigs
if !allZero(in[32:63]) || !crypto.ValidateSignatureValues(v, r, s, false) {
log.Trace("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 {
log.Trace(fmt.Sprint("ECRECOVER error: ", err))
return nil
}
// the first byte of pubkey is bitcoin heritage
return common.LeftPadBytes(crypto.Keccak256(pubKey[1:])[12:], 32)
}
// SHA256 implemented as a native contract
type sha256hash struct{}
// RequiredGas returns the gas required to execute the pre-compiled contract.
//
// This method does not require any overflow checking as the input size gas costs
// required for anything significant is so high it's impossible to pay for.
func (c *sha256hash) RequiredGas(inputSize int) uint64 {
return uint64(inputSize+31)/32*params.Sha256WordGas + params.Sha256Gas
}
func (c *sha256hash) Run(in []byte) []byte {
h := sha256.Sum256(in)
return h[:]
}
// RIPMED160 implemented as a native contract
type ripemd160hash struct{}
// RequiredGas returns the gas required to execute the pre-compiled contract.
//
// This method does not require any overflow checking as the input size gas costs
// required for anything significant is so high it's impossible to pay for.
func (c *ripemd160hash) RequiredGas(inputSize int) uint64 {
return uint64(inputSize+31)/32*params.Ripemd160WordGas + params.Ripemd160Gas
}
func (c *ripemd160hash) Run(in []byte) []byte {
ripemd := ripemd160.New()
ripemd.Write(in)
return common.LeftPadBytes(ripemd.Sum(nil), 32)
}
// data copy implemented as a native contract
type dataCopy struct{}
// RequiredGas returns the gas required to execute the pre-compiled contract.
//
// This method does not require any overflow checking as the input size gas costs
// required for anything significant is so high it's impossible to pay for.
func (c *dataCopy) RequiredGas(inputSize int) uint64 {
return uint64(inputSize+31)/32*params.IdentityWordGas + params.IdentityGas
}
func (c *dataCopy) Run(in []byte) []byte {
return in
}