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authorDeterminant <[email protected]>2020-06-28 14:47:41 -0400
committerDeterminant <[email protected]>2020-06-28 14:47:41 -0400
commitd235e2c6a5788ec4a6cff15a16f56b38a3876a0d (patch)
tree5f2727f7a50ee5840f889c82776d3a30a88dd59b /core/vm/contracts.go
parent13ebd8bd9468e9d769d598b0ca2afb72ba78cb97 (diff)
...
Diffstat (limited to 'core/vm/contracts.go')
-rw-r--r--core/vm/contracts.go497
1 files changed, 497 insertions, 0 deletions
diff --git a/core/vm/contracts.go b/core/vm/contracts.go
new file mode 100644
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+++ b/core/vm/contracts.go
@@ -0,0 +1,497 @@
+// 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"
+ "encoding/binary"
+ "errors"
+ "math/big"
+
+ "github.com/ava-labs/coreth/params"
+ "github.com/ava-labs/go-ethereum/common"
+ "github.com/ava-labs/go-ethereum/common/math"
+ "github.com/ava-labs/go-ethereum/crypto"
+ "github.com/ava-labs/go-ethereum/crypto/blake2b"
+ "github.com/ava-labs/go-ethereum/crypto/bn256"
+ "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}): &bn256AddByzantium{},
+ common.BytesToAddress([]byte{7}): &bn256ScalarMulByzantium{},
+ common.BytesToAddress([]byte{8}): &bn256PairingByzantium{},
+}
+
+// PrecompiledContractsIstanbul contains the default set of pre-compiled Ethereum
+// contracts used in the Istanbul release.
+var PrecompiledContractsIstanbul = 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}): &bn256AddIstanbul{},
+ common.BytesToAddress([]byte{7}): &bn256ScalarMulIstanbul{},
+ common.BytesToAddress([]byte{8}): &bn256PairingIstanbul{},
+ common.BytesToAddress([]byte{9}): &blake2F{},
+}
+
+// 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, 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 !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(getData(input, 0, 32))
+ expLen = new(big.Int).SetBytes(getData(input, 32, 32))
+ modLen = new(big.Int).SetBytes(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(getData(input, baseLen.Uint64(), 32))
+ } else {
+ expHead = new(big.Int).SetBytes(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(getData(input, 0, 32)).Uint64()
+ expLen = new(big.Int).SetBytes(getData(input, 32, 32)).Uint64()
+ modLen = new(big.Int).SetBytes(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(getData(input, 0, baseLen))
+ exp = new(big.Int).SetBytes(getData(input, baseLen, expLen))
+ mod = new(big.Int).SetBytes(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
+}
+
+// runBn256Add implements the Bn256Add precompile, referenced by both
+// Byzantium and Istanbul operations.
+func runBn256Add(input []byte) ([]byte, error) {
+ x, err := newCurvePoint(getData(input, 0, 64))
+ if err != nil {
+ return nil, err
+ }
+ y, err := newCurvePoint(getData(input, 64, 64))
+ if err != nil {
+ return nil, err
+ }
+ res := new(bn256.G1)
+ res.Add(x, y)
+ return res.Marshal(), nil
+}
+
+// bn256Add implements a native elliptic curve point addition conforming to
+// Istanbul consensus rules.
+type bn256AddIstanbul struct{}
+
+// RequiredGas returns the gas required to execute the pre-compiled contract.
+func (c *bn256AddIstanbul) RequiredGas(input []byte) uint64 {
+ return params.Bn256AddGasIstanbul
+}
+
+func (c *bn256AddIstanbul) Run(input []byte) ([]byte, error) {
+ return runBn256Add(input)
+}
+
+// bn256AddByzantium implements a native elliptic curve point addition
+// conforming to Byzantium consensus rules.
+type bn256AddByzantium struct{}
+
+// RequiredGas returns the gas required to execute the pre-compiled contract.
+func (c *bn256AddByzantium) RequiredGas(input []byte) uint64 {
+ return params.Bn256AddGasByzantium
+}
+
+func (c *bn256AddByzantium) Run(input []byte) ([]byte, error) {
+ return runBn256Add(input)
+}
+
+// runBn256ScalarMul implements the Bn256ScalarMul precompile, referenced by
+// both Byzantium and Istanbul operations.
+func runBn256ScalarMul(input []byte) ([]byte, error) {
+ p, err := newCurvePoint(getData(input, 0, 64))
+ if err != nil {
+ return nil, err
+ }
+ res := new(bn256.G1)
+ res.ScalarMult(p, new(big.Int).SetBytes(getData(input, 64, 32)))
+ return res.Marshal(), nil
+}
+
+// bn256ScalarMulIstanbul implements a native elliptic curve scalar
+// multiplication conforming to Istanbul consensus rules.
+type bn256ScalarMulIstanbul struct{}
+
+// RequiredGas returns the gas required to execute the pre-compiled contract.
+func (c *bn256ScalarMulIstanbul) RequiredGas(input []byte) uint64 {
+ return params.Bn256ScalarMulGasIstanbul
+}
+
+func (c *bn256ScalarMulIstanbul) Run(input []byte) ([]byte, error) {
+ return runBn256ScalarMul(input)
+}
+
+// bn256ScalarMulByzantium implements a native elliptic curve scalar
+// multiplication conforming to Byzantium consensus rules.
+type bn256ScalarMulByzantium struct{}
+
+// RequiredGas returns the gas required to execute the pre-compiled contract.
+func (c *bn256ScalarMulByzantium) RequiredGas(input []byte) uint64 {
+ return params.Bn256ScalarMulGasByzantium
+}
+
+func (c *bn256ScalarMulByzantium) Run(input []byte) ([]byte, error) {
+ return runBn256ScalarMul(input)
+}
+
+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")
+)
+
+// runBn256Pairing implements the Bn256Pairing precompile, referenced by both
+// Byzantium and Istanbul operations.
+func runBn256Pairing(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
+}
+
+// bn256PairingIstanbul implements a pairing pre-compile for the bn256 curve
+// conforming to Istanbul consensus rules.
+type bn256PairingIstanbul struct{}
+
+// RequiredGas returns the gas required to execute the pre-compiled contract.
+func (c *bn256PairingIstanbul) RequiredGas(input []byte) uint64 {
+ return params.Bn256PairingBaseGasIstanbul + uint64(len(input)/192)*params.Bn256PairingPerPointGasIstanbul
+}
+
+func (c *bn256PairingIstanbul) Run(input []byte) ([]byte, error) {
+ return runBn256Pairing(input)
+}
+
+// bn256PairingByzantium implements a pairing pre-compile for the bn256 curve
+// conforming to Byzantium consensus rules.
+type bn256PairingByzantium struct{}
+
+// RequiredGas returns the gas required to execute the pre-compiled contract.
+func (c *bn256PairingByzantium) RequiredGas(input []byte) uint64 {
+ return params.Bn256PairingBaseGasByzantium + uint64(len(input)/192)*params.Bn256PairingPerPointGasByzantium
+}
+
+func (c *bn256PairingByzantium) Run(input []byte) ([]byte, error) {
+ return runBn256Pairing(input)
+}
+
+type blake2F struct{}
+
+func (c *blake2F) RequiredGas(input []byte) uint64 {
+ // If the input is malformed, we can't calculate the gas, return 0 and let the
+ // actual call choke and fault.
+ if len(input) != blake2FInputLength {
+ return 0
+ }
+ return uint64(binary.BigEndian.Uint32(input[0:4]))
+}
+
+const (
+ blake2FInputLength = 213
+ blake2FFinalBlockBytes = byte(1)
+ blake2FNonFinalBlockBytes = byte(0)
+)
+
+var (
+ errBlake2FInvalidInputLength = errors.New("invalid input length")
+ errBlake2FInvalidFinalFlag = errors.New("invalid final flag")
+)
+
+func (c *blake2F) Run(input []byte) ([]byte, error) {
+ // Make sure the input is valid (correct lenth and final flag)
+ if len(input) != blake2FInputLength {
+ return nil, errBlake2FInvalidInputLength
+ }
+ if input[212] != blake2FNonFinalBlockBytes && input[212] != blake2FFinalBlockBytes {
+ return nil, errBlake2FInvalidFinalFlag
+ }
+ // Parse the input into the Blake2b call parameters
+ var (
+ rounds = binary.BigEndian.Uint32(input[0:4])
+ final = (input[212] == blake2FFinalBlockBytes)
+
+ h [8]uint64
+ m [16]uint64
+ t [2]uint64
+ )
+ for i := 0; i < 8; i++ {
+ offset := 4 + i*8
+ h[i] = binary.LittleEndian.Uint64(input[offset : offset+8])
+ }
+ for i := 0; i < 16; i++ {
+ offset := 68 + i*8
+ m[i] = binary.LittleEndian.Uint64(input[offset : offset+8])
+ }
+ t[0] = binary.LittleEndian.Uint64(input[196:204])
+ t[1] = binary.LittleEndian.Uint64(input[204:212])
+
+ // Execute the compression function, extract and return the result
+ blake2b.F(&h, m, t, final, rounds)
+
+ output := make([]byte, 64)
+ for i := 0; i < 8; i++ {
+ offset := i * 8
+ binary.LittleEndian.PutUint64(output[offset:offset+8], h[i])
+ }
+ return output, nil
+}