core: add Metropolis pre-compiles (EIP 197, 198 and 213)
This commit is contained in:
Jeffrey Wilcke
committed by
Péter Szilágyi
Péter Szilágyi
parent
6ca59d98f8
commit
7bbdf3e268
@ -22,7 +22,9 @@ 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/common/math"
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"github.com/ethereum/go-ethereum/crypto"
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"github.com/ethereum/go-ethereum/crypto/bn256"
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"github.com/ethereum/go-ethereum/params"
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"golang.org/x/crypto/ripemd160"
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)
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@ -45,6 +47,19 @@ var PrecompiledContracts = map[common.Address]PrecompiledContract{
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common.BytesToAddress([]byte{4}): &dataCopy{},
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}
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// PrecompiledContractsMetropolis contains the default set of ethereum contracts
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// for metropolis hardfork
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var PrecompiledContractsMetropolis = map[common.Address]PrecompiledContract{
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common.BytesToAddress([]byte{1}): &ecrecover{},
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common.BytesToAddress([]byte{2}): &sha256hash{},
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common.BytesToAddress([]byte{3}): &ripemd160hash{},
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common.BytesToAddress([]byte{4}): &dataCopy{},
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common.BytesToAddress([]byte{5}): &bigModexp{},
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common.BytesToAddress([]byte{6}): &bn256Add{},
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common.BytesToAddress([]byte{7}): &bn256ScalarMul{},
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common.BytesToAddress([]byte{8}): &pairing{},
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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(input)
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@ -132,3 +147,190 @@ func (c *dataCopy) RequiredGas(input []byte) uint64 {
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func (c *dataCopy) Run(in []byte) ([]byte, error) {
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return in, nil
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}
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// bigModexp implements a native big integer exponential modular operation.
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type bigModexp 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 *bigModexp) RequiredGas(input []byte) uint64 {
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// TODO reword required gas to have error reporting and convert arithmetic
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// to uint64.
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if len(input) < 3*32 {
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input = append(input, make([]byte, 3*32-len(input))...)
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}
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var (
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baseLen = new(big.Int).SetBytes(input[:31])
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expLen = math.BigMax(new(big.Int).SetBytes(input[32:64]), big.NewInt(1))
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modLen = new(big.Int).SetBytes(input[65:97])
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)
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x := new(big.Int).Set(math.BigMax(baseLen, modLen))
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x.Mul(x, x)
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x.Mul(x, expLen)
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x.Div(x, new(big.Int).SetUint64(params.QuadCoeffDiv))
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return x.Uint64()
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}
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func (c *bigModexp) Run(input []byte) ([]byte, error) {
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if len(input) < 3*32 {
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input = append(input, make([]byte, 3*32-len(input))...)
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}
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// why 32-byte? These values won't fit anyway
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var (
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baseLen = new(big.Int).SetBytes(input[:32]).Uint64()
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expLen = new(big.Int).SetBytes(input[32:64]).Uint64()
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modLen = new(big.Int).SetBytes(input[64:96]).Uint64()
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)
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input = input[96:]
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if uint64(len(input)) < baseLen {
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input = append(input, make([]byte, baseLen-uint64(len(input)))...)
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}
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base := new(big.Int).SetBytes(input[:baseLen])
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input = input[baseLen:]
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if uint64(len(input)) < expLen {
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input = append(input, make([]byte, expLen-uint64(len(input)))...)
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}
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exp := new(big.Int).SetBytes(input[:expLen])
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input = input[expLen:]
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if uint64(len(input)) < modLen {
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input = append(input, make([]byte, modLen-uint64(len(input)))...)
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}
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mod := new(big.Int).SetBytes(input[:modLen])
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return common.LeftPadBytes(base.Exp(base, exp, mod).Bytes(), len(input[:modLen])), nil
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}
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type bn256Add 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 *bn256Add) RequiredGas(input []byte) uint64 {
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return 0 // TODO
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}
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func (c *bn256Add) Run(in []byte) ([]byte, error) {
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in = common.RightPadBytes(in, 128)
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x, onCurve := new(bn256.G1).Unmarshal(in[:64])
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if !onCurve {
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return nil, errNotOnCurve
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}
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gx, gy, _, _ := x.CurvePoints()
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if gx.Cmp(bn256.P) >= 0 || gy.Cmp(bn256.P) >= 0 {
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return nil, errInvalidCurvePoint
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}
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y, onCurve := new(bn256.G1).Unmarshal(in[64:128])
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if !onCurve {
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return nil, errNotOnCurve
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}
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gx, gy, _, _ = y.CurvePoints()
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if gx.Cmp(bn256.P) >= 0 || gy.Cmp(bn256.P) >= 0 {
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return nil, errInvalidCurvePoint
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}
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x.Add(x, y)
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return x.Marshal(), nil
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}
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type bn256ScalarMul 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 *bn256ScalarMul) RequiredGas(input []byte) uint64 {
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return 0 // TODO
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}
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func (c *bn256ScalarMul) Run(in []byte) ([]byte, error) {
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in = common.RightPadBytes(in, 96)
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g1, onCurve := new(bn256.G1).Unmarshal(in[:64])
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if !onCurve {
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return nil, errNotOnCurve
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}
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x, y, _, _ := g1.CurvePoints()
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if x.Cmp(bn256.P) >= 0 || y.Cmp(bn256.P) >= 0 {
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return nil, errInvalidCurvePoint
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}
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g1.ScalarMult(g1, new(big.Int).SetBytes(in[64:96]))
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return g1.Marshal(), nil
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}
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// pairing implements a pairing pre-compile for the bn256 curve
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type pairing 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 *pairing) RequiredGas(input []byte) uint64 {
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//return 0 // TODO
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k := (len(input) + 191) / pairSize
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return uint64(60000*k + 40000)
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}
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const pairSize = 192
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var (
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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}
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fals32Byte = make([]byte, 32)
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errNotOnCurve = errors.New("point not on elliptic curve")
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errInvalidCurvePoint = errors.New("invalid elliptic curve point")
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)
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func (c *pairing) Run(in []byte) ([]byte, error) {
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if len(in) == 0 {
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return true32Byte, nil
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}
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if len(in)%pairSize > 0 {
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return nil, errBadPrecompileInput
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}
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var (
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g1s []*bn256.G1
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g2s []*bn256.G2
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)
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for i := 0; i < len(in); i += pairSize {
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g1, onCurve := new(bn256.G1).Unmarshal(in[i : i+64])
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if !onCurve {
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return nil, errNotOnCurve
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}
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x, y, _, _ := g1.CurvePoints()
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if x.Cmp(bn256.P) >= 0 || y.Cmp(bn256.P) >= 0 {
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return nil, errInvalidCurvePoint
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}
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g2, onCurve := new(bn256.G2).Unmarshal(in[i+64 : i+192])
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if !onCurve {
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return nil, errNotOnCurve
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}
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x2, y2, _, _ := g2.CurvePoints()
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if x2.Real().Cmp(bn256.P) >= 0 || x2.Imag().Cmp(bn256.P) >= 0 ||
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y2.Real().Cmp(bn256.P) >= 0 || y2.Imag().Cmp(bn256.P) >= 0 {
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return nil, errInvalidCurvePoint
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}
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g1s = append(g1s, g1)
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g2s = append(g2s, g2)
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}
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isOne := bn256.PairingCheck(g1s, g2s)
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if isOne {
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return true32Byte, nil
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}
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return fals32Byte, nil
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}
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