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author | jm <jm.huang@cobinhood.com> | 2019-01-15 00:48:13 +0800 |
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committer | Jhih-Ming Huang <jm.huang@cobinhood.com> | 2019-05-06 10:44:03 +0800 |
commit | 266068a53cdf9e06acacf982d63653c03133a634 (patch) | |
tree | af2d74e6adb309adfe39bafaa2f540fe0bcd1a31 /core/vm/evm/contracts.go | |
parent | d41cb421d755b8f0bca87b7476f26aa4b879b9d9 (diff) | |
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core: vm: refactor file structure
For support other vm types, this pr modified the core/vm file
structures.
Diffstat (limited to 'core/vm/evm/contracts.go')
-rw-r--r-- | core/vm/evm/contracts.go | 361 |
1 files changed, 361 insertions, 0 deletions
diff --git a/core/vm/evm/contracts.go b/core/vm/evm/contracts.go new file mode 100644 index 000000000..52bb0a83b --- /dev/null +++ b/core/vm/evm/contracts.go @@ -0,0 +1,361 @@ +// 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 evm + +import ( + "crypto/sha256" + "errors" + "math/big" + + "github.com/dexon-foundation/dexon/common" + "github.com/dexon-foundation/dexon/common/math" + "github.com/dexon-foundation/dexon/core/vm" + "github.com/dexon-foundation/dexon/crypto" + "github.com/dexon-foundation/dexon/crypto/bn256" + "github.com/dexon-foundation/dexon/params" + "golang.org/x/crypto/ripemd160" +) + +// PrecompiledContract 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(input []byte) uint64 // RequiredPrice calculates the contract gas use + Run(input []byte) ([]byte, error) // Run runs the precompiled contract +} + +// PrecompiledContractsHomestead contains the default set of pre-compiled Ethereum +// contracts used in the Frontier and Homestead releases. +var PrecompiledContractsHomestead = map[common.Address]PrecompiledContract{ + common.BytesToAddress([]byte{1}): &ecrecover{}, + common.BytesToAddress([]byte{2}): &sha256hash{}, + common.BytesToAddress([]byte{3}): &ripemd160hash{}, + common.BytesToAddress([]byte{4}): &dataCopy{}, +} + +// PrecompiledContractsByzantium contains the default set of pre-compiled Ethereum +// contracts used in the Byzantium release. +var PrecompiledContractsByzantium = map[common.Address]PrecompiledContract{ + common.BytesToAddress([]byte{1}): &ecrecover{}, + common.BytesToAddress([]byte{2}): &sha256hash{}, + common.BytesToAddress([]byte{3}): &ripemd160hash{}, + common.BytesToAddress([]byte{4}): &dataCopy{}, + common.BytesToAddress([]byte{5}): &bigModExp{}, + common.BytesToAddress([]byte{6}): &bn256Add{}, + common.BytesToAddress([]byte{7}): &bn256ScalarMul{}, + common.BytesToAddress([]byte{8}): &bn256Pairing{}, +} + +// RunPrecompiledContract runs and evaluates the output of a precompiled contract. +func RunPrecompiledContract(p PrecompiledContract, input []byte, contract *Contract) (ret []byte, err error) { + gas := p.RequiredGas(input) + if contract.UseGas(gas) { + return p.Run(input) + } + return nil, vm.ErrOutOfGas +} + +// ECRECOVER implemented as a native contract. +type ecrecover struct{} + +func (c *ecrecover) RequiredGas(input []byte) uint64 { + return params.EcrecoverGas +} + +func (c *ecrecover) Run(input []byte) ([]byte, error) { + const ecRecoverInputLength = 128 + + input = common.RightPadBytes(input, ecRecoverInputLength) + // "input" is (hash, v, r, s), each 32 bytes + // but for ecrecover we want (r, s, v) + + r := new(big.Int).SetBytes(input[64:96]) + s := new(big.Int).SetBytes(input[96:128]) + v := input[63] - 27 + + // tighter sig s values input homestead only apply to tx sigs + if !vm.AllZero(input[32:63]) || !crypto.ValidateSignatureValues(v, r, s, false) { + return nil, nil + } + // v needs to be at the end for libsecp256k1 + pubKey, err := crypto.Ecrecover(input[:32], append(input[64:128], v)) + // make sure the public key is a valid one + if err != nil { + return nil, nil + } + + // the first byte of pubkey is bitcoin heritage + return common.LeftPadBytes(crypto.Keccak256(pubKey[1:])[12:], 32), nil +} + +// 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(input []byte) uint64 { + return uint64(len(input)+31)/32*params.Sha256PerWordGas + params.Sha256BaseGas +} +func (c *sha256hash) Run(input []byte) ([]byte, error) { + h := sha256.Sum256(input) + return h[:], nil +} + +// RIPEMD160 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(input []byte) uint64 { + return uint64(len(input)+31)/32*params.Ripemd160PerWordGas + params.Ripemd160BaseGas +} +func (c *ripemd160hash) Run(input []byte) ([]byte, error) { + ripemd := ripemd160.New() + ripemd.Write(input) + return common.LeftPadBytes(ripemd.Sum(nil), 32), nil +} + +// 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(input []byte) uint64 { + return uint64(len(input)+31)/32*params.IdentityPerWordGas + params.IdentityBaseGas +} +func (c *dataCopy) Run(in []byte) ([]byte, error) { + return in, nil +} + +// bigModExp implements a native big integer exponential modular operation. +type bigModExp struct{} + +var ( + big1 = big.NewInt(1) + big4 = big.NewInt(4) + big8 = big.NewInt(8) + big16 = big.NewInt(16) + big32 = big.NewInt(32) + big64 = big.NewInt(64) + big96 = big.NewInt(96) + big480 = big.NewInt(480) + big1024 = big.NewInt(1024) + big3072 = big.NewInt(3072) + big199680 = big.NewInt(199680) +) + +// RequiredGas returns the gas required to execute the pre-compiled contract. +func (c *bigModExp) RequiredGas(input []byte) uint64 { + var ( + baseLen = new(big.Int).SetBytes(vm.GetData(input, 0, 32)) + expLen = new(big.Int).SetBytes(vm.GetData(input, 32, 32)) + modLen = new(big.Int).SetBytes(vm.GetData(input, 64, 32)) + ) + if len(input) > 96 { + input = input[96:] + } else { + input = input[:0] + } + // Retrieve the head 32 bytes of exp for the adjusted exponent length + var expHead *big.Int + if big.NewInt(int64(len(input))).Cmp(baseLen) <= 0 { + expHead = new(big.Int) + } else { + if expLen.Cmp(big32) > 0 { + expHead = new(big.Int).SetBytes(vm.GetData(input, baseLen.Uint64(), 32)) + } else { + expHead = new(big.Int).SetBytes(vm.GetData(input, baseLen.Uint64(), expLen.Uint64())) + } + } + // Calculate the adjusted exponent length + var msb int + if bitlen := expHead.BitLen(); bitlen > 0 { + msb = bitlen - 1 + } + adjExpLen := new(big.Int) + if expLen.Cmp(big32) > 0 { + adjExpLen.Sub(expLen, big32) + adjExpLen.Mul(big8, adjExpLen) + } + adjExpLen.Add(adjExpLen, big.NewInt(int64(msb))) + + // Calculate the gas cost of the operation + gas := new(big.Int).Set(math.BigMax(modLen, baseLen)) + switch { + case gas.Cmp(big64) <= 0: + gas.Mul(gas, gas) + case gas.Cmp(big1024) <= 0: + gas = new(big.Int).Add( + new(big.Int).Div(new(big.Int).Mul(gas, gas), big4), + new(big.Int).Sub(new(big.Int).Mul(big96, gas), big3072), + ) + default: + gas = new(big.Int).Add( + new(big.Int).Div(new(big.Int).Mul(gas, gas), big16), + new(big.Int).Sub(new(big.Int).Mul(big480, gas), big199680), + ) + } + gas.Mul(gas, math.BigMax(adjExpLen, big1)) + gas.Div(gas, new(big.Int).SetUint64(params.ModExpQuadCoeffDiv)) + + if gas.BitLen() > 64 { + return math.MaxUint64 + } + return gas.Uint64() +} + +func (c *bigModExp) Run(input []byte) ([]byte, error) { + var ( + baseLen = new(big.Int).SetBytes(vm.GetData(input, 0, 32)).Uint64() + expLen = new(big.Int).SetBytes(vm.GetData(input, 32, 32)).Uint64() + modLen = new(big.Int).SetBytes(vm.GetData(input, 64, 32)).Uint64() + ) + if len(input) > 96 { + input = input[96:] + } else { + input = input[:0] + } + // Handle a special case when both the base and mod length is zero + if baseLen == 0 && modLen == 0 { + return []byte{}, nil + } + // Retrieve the operands and execute the exponentiation + var ( + base = new(big.Int).SetBytes(vm.GetData(input, 0, baseLen)) + exp = new(big.Int).SetBytes(vm.GetData(input, baseLen, expLen)) + mod = new(big.Int).SetBytes(vm.GetData(input, baseLen+expLen, modLen)) + ) + if mod.BitLen() == 0 { + // Modulo 0 is undefined, return zero + return common.LeftPadBytes([]byte{}, int(modLen)), nil + } + return common.LeftPadBytes(base.Exp(base, exp, mod).Bytes(), int(modLen)), nil +} + +// newCurvePoint unmarshals a binary blob into a bn256 elliptic curve point, +// returning it, or an error if the point is invalid. +func newCurvePoint(blob []byte) (*bn256.G1, error) { + p := new(bn256.G1) + if _, err := p.Unmarshal(blob); err != nil { + return nil, err + } + return p, nil +} + +// newTwistPoint unmarshals a binary blob into a bn256 elliptic curve point, +// returning it, or an error if the point is invalid. +func newTwistPoint(blob []byte) (*bn256.G2, error) { + p := new(bn256.G2) + if _, err := p.Unmarshal(blob); err != nil { + return nil, err + } + return p, nil +} + +// bn256Add implements a native elliptic curve point addition. +type bn256Add struct{} + +// RequiredGas returns the gas required to execute the pre-compiled contract. +func (c *bn256Add) RequiredGas(input []byte) uint64 { + return params.Bn256AddGas +} + +func (c *bn256Add) Run(input []byte) ([]byte, error) { + x, err := newCurvePoint(vm.GetData(input, 0, 64)) + if err != nil { + return nil, err + } + y, err := newCurvePoint(vm.GetData(input, 64, 64)) + if err != nil { + return nil, err + } + res := new(bn256.G1) + res.Add(x, y) + return res.Marshal(), nil +} + +// bn256ScalarMul implements a native elliptic curve scalar multiplication. +type bn256ScalarMul struct{} + +// RequiredGas returns the gas required to execute the pre-compiled contract. +func (c *bn256ScalarMul) RequiredGas(input []byte) uint64 { + return params.Bn256ScalarMulGas +} + +func (c *bn256ScalarMul) Run(input []byte) ([]byte, error) { + p, err := newCurvePoint(vm.GetData(input, 0, 64)) + if err != nil { + return nil, err + } + res := new(bn256.G1) + res.ScalarMult(p, new(big.Int).SetBytes(vm.GetData(input, 64, 32))) + return res.Marshal(), nil +} + +var ( + // true32Byte is returned if the bn256 pairing check succeeds. + true32Byte = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1} + + // false32Byte is returned if the bn256 pairing check fails. + false32Byte = make([]byte, 32) + + // errBadPairingInput is returned if the bn256 pairing input is invalid. + errBadPairingInput = errors.New("bad elliptic curve pairing size") +) + +// bn256Pairing implements a pairing pre-compile for the bn256 curve +type bn256Pairing struct{} + +// RequiredGas returns the gas required to execute the pre-compiled contract. +func (c *bn256Pairing) RequiredGas(input []byte) uint64 { + return params.Bn256PairingBaseGas + uint64(len(input)/192)*params.Bn256PairingPerPointGas +} + +func (c *bn256Pairing) Run(input []byte) ([]byte, error) { + // Handle some corner cases cheaply + if len(input)%192 > 0 { + return nil, errBadPairingInput + } + // Convert the input into a set of coordinates + var ( + cs []*bn256.G1 + ts []*bn256.G2 + ) + for i := 0; i < len(input); i += 192 { + c, err := newCurvePoint(input[i : i+64]) + if err != nil { + return nil, err + } + t, err := newTwistPoint(input[i+64 : i+192]) + if err != nil { + return nil, err + } + cs = append(cs, c) + ts = append(ts, t) + } + // Execute the pairing checks and return the results + if bn256.PairingCheck(cs, ts) { + return true32Byte, nil + } + return false32Byte, nil +} |