github.com/insight-chain/inb-go@v1.1.3-0.20191221022159-da049980ae38/core/vm/contracts.go (about) 1 // Copyright 2014 The go-ethereum Authors 2 // This file is part of the go-ethereum library. 3 // 4 // The go-ethereum library is free software: you can redistribute it and/or modify 5 // it under the terms of the GNU Lesser General Public License as published by 6 // the Free Software Foundation, either version 3 of the License, or 7 // (at your option) any later version. 8 // 9 // The go-ethereum library is distributed in the hope that it will be useful, 10 // but WITHOUT ANY WARRANTY; without even the implied warranty of 11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 // GNU Lesser General Public License for more details. 13 // 14 // You should have received a copy of the GNU Lesser General Public License 15 // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>. 16 17 package vm 18 19 import ( 20 "crypto/sha256" 21 "errors" 22 "math/big" 23 24 "github.com/insight-chain/inb-go/common" 25 "github.com/insight-chain/inb-go/common/math" 26 "github.com/insight-chain/inb-go/crypto" 27 "github.com/insight-chain/inb-go/crypto/bn256" 28 "github.com/insight-chain/inb-go/params" 29 "golang.org/x/crypto/ripemd160" 30 ) 31 32 // PrecompiledContract is the basic interface for native Go contracts. The implementation 33 // requires a deterministic gas count based on the input size of the Run method of the 34 // contract. 35 type PrecompiledContract interface { 36 RequiredGas(input []byte) uint64 // RequiredPrice calculates the contract gas use 37 Run(input []byte) ([]byte, error) // Run runs the precompiled contract 38 } 39 40 // PrecompiledContractsHomestead contains the default set of pre-compiled Ethereum 41 // contracts used in the Frontier and Homestead releases. 42 var PrecompiledContractsHomestead = map[common.Address]PrecompiledContract{ 43 common.BytesToAddress([]byte{1}): &ecrecover{}, 44 common.BytesToAddress([]byte{2}): &sha256hash{}, 45 common.BytesToAddress([]byte{3}): &ripemd160hash{}, 46 common.BytesToAddress([]byte{4}): &dataCopy{}, 47 } 48 49 // PrecompiledContractsByzantium contains the default set of pre-compiled Ethereum 50 // contracts used in the Byzantium release. 51 var PrecompiledContractsByzantium = map[common.Address]PrecompiledContract{ 52 common.BytesToAddress([]byte{1}): &ecrecover{}, 53 common.BytesToAddress([]byte{2}): &sha256hash{}, 54 common.BytesToAddress([]byte{3}): &ripemd160hash{}, 55 common.BytesToAddress([]byte{4}): &dataCopy{}, 56 common.BytesToAddress([]byte{5}): &bigModExp{}, 57 common.BytesToAddress([]byte{6}): &bn256Add{}, 58 common.BytesToAddress([]byte{7}): &bn256ScalarMul{}, 59 common.BytesToAddress([]byte{8}): &bn256Pairing{}, 60 } 61 62 // RunPrecompiledContract runs and evaluates the output of a precompiled contract. 63 func RunPrecompiledContract(p PrecompiledContract, input []byte, contract *Contract) (ret []byte, err error) { 64 gas := p.RequiredGas(input) 65 if contract.UseGas(gas) { 66 return p.Run(input) 67 } 68 return nil, ErrOutOfGas 69 } 70 71 // ECRECOVER implemented as a native contract. 72 type ecrecover struct{} 73 74 func (c *ecrecover) RequiredGas(input []byte) uint64 { 75 return params.EcrecoverGas 76 } 77 78 func (c *ecrecover) Run(input []byte) ([]byte, error) { 79 const ecRecoverInputLength = 128 80 81 input = common.RightPadBytes(input, ecRecoverInputLength) 82 // "input" is (hash, v, r, s), each 32 bytes 83 // but for ecrecover we want (r, s, v) 84 85 r := new(big.Int).SetBytes(input[64:96]) 86 s := new(big.Int).SetBytes(input[96:128]) 87 v := input[63] - 27 88 89 // tighter sig s values input homestead only apply to tx sigs 90 if !allZero(input[32:63]) || !crypto.ValidateSignatureValues(v, r, s, false) { 91 return nil, nil 92 } 93 // v needs to be at the end for libsecp256k1 94 pubKey, err := crypto.Ecrecover(input[:32], append(input[64:128], v)) 95 // make sure the public key is a valid one 96 if err != nil { 97 return nil, nil 98 } 99 100 // the first byte of pubkey is bitcoin heritage 101 102 return common.LeftPadBytes(crypto.Keccak256(pubKey[1:])[12:], 32), nil 103 } 104 105 // SHA256 implemented as a native contract. 106 type sha256hash struct{} 107 108 // RequiredGas returns the gas required to execute the pre-compiled contract. 109 // 110 // This method does not require any overflow checking as the input size gas costs 111 // required for anything significant is so high it's impossible to pay for. 112 func (c *sha256hash) RequiredGas(input []byte) uint64 { 113 return uint64(len(input)+31)/32*params.Sha256PerWordGas + params.Sha256BaseGas 114 } 115 func (c *sha256hash) Run(input []byte) ([]byte, error) { 116 h := sha256.Sum256(input) 117 return h[:], nil 118 } 119 120 // RIPEMD160 implemented as a native contract. 121 type ripemd160hash struct{} 122 123 // RequiredGas returns the gas required to execute the pre-compiled contract. 124 // 125 // This method does not require any overflow checking as the input size gas costs 126 // required for anything significant is so high it's impossible to pay for. 127 func (c *ripemd160hash) RequiredGas(input []byte) uint64 { 128 return uint64(len(input)+31)/32*params.Ripemd160PerWordGas + params.Ripemd160BaseGas 129 } 130 func (c *ripemd160hash) Run(input []byte) ([]byte, error) { 131 ripemd := ripemd160.New() 132 ripemd.Write(input) 133 return common.LeftPadBytes(ripemd.Sum(nil), 32), nil 134 } 135 136 // data copy implemented as a native contract. 137 type dataCopy struct{} 138 139 // RequiredGas returns the gas required to execute the pre-compiled contract. 140 // 141 // This method does not require any overflow checking as the input size gas costs 142 // required for anything significant is so high it's impossible to pay for. 143 func (c *dataCopy) RequiredGas(input []byte) uint64 { 144 return uint64(len(input)+31)/32*params.IdentityPerWordGas + params.IdentityBaseGas 145 } 146 func (c *dataCopy) Run(in []byte) ([]byte, error) { 147 return in, nil 148 } 149 150 // bigModExp implements a native big integer exponential modular operation. 151 type bigModExp struct{} 152 153 var ( 154 big1 = big.NewInt(1) 155 big4 = big.NewInt(4) 156 big8 = big.NewInt(8) 157 big16 = big.NewInt(16) 158 big32 = big.NewInt(32) 159 big64 = big.NewInt(64) 160 big96 = big.NewInt(96) 161 big480 = big.NewInt(480) 162 big1024 = big.NewInt(1024) 163 big3072 = big.NewInt(3072) 164 big199680 = big.NewInt(199680) 165 ) 166 167 // RequiredGas returns the gas required to execute the pre-compiled contract. 168 func (c *bigModExp) RequiredGas(input []byte) uint64 { 169 var ( 170 baseLen = new(big.Int).SetBytes(getData(input, 0, 32)) 171 expLen = new(big.Int).SetBytes(getData(input, 32, 32)) 172 modLen = new(big.Int).SetBytes(getData(input, 64, 32)) 173 ) 174 if len(input) > 96 { 175 input = input[96:] 176 } else { 177 input = input[:0] 178 } 179 // Retrieve the head 32 bytes of exp for the adjusted exponent length 180 var expHead *big.Int 181 if big.NewInt(int64(len(input))).Cmp(baseLen) <= 0 { 182 expHead = new(big.Int) 183 } else { 184 if expLen.Cmp(big32) > 0 { 185 expHead = new(big.Int).SetBytes(getData(input, baseLen.Uint64(), 32)) 186 } else { 187 expHead = new(big.Int).SetBytes(getData(input, baseLen.Uint64(), expLen.Uint64())) 188 } 189 } 190 // Calculate the adjusted exponent length 191 var msb int 192 if bitlen := expHead.BitLen(); bitlen > 0 { 193 msb = bitlen - 1 194 } 195 adjExpLen := new(big.Int) 196 if expLen.Cmp(big32) > 0 { 197 adjExpLen.Sub(expLen, big32) 198 adjExpLen.Mul(big8, adjExpLen) 199 } 200 adjExpLen.Add(adjExpLen, big.NewInt(int64(msb))) 201 202 // Calculate the gas cost of the operation 203 gas := new(big.Int).Set(math.BigMax(modLen, baseLen)) 204 switch { 205 case gas.Cmp(big64) <= 0: 206 gas.Mul(gas, gas) 207 case gas.Cmp(big1024) <= 0: 208 gas = new(big.Int).Add( 209 new(big.Int).Div(new(big.Int).Mul(gas, gas), big4), 210 new(big.Int).Sub(new(big.Int).Mul(big96, gas), big3072), 211 ) 212 default: 213 gas = new(big.Int).Add( 214 new(big.Int).Div(new(big.Int).Mul(gas, gas), big16), 215 new(big.Int).Sub(new(big.Int).Mul(big480, gas), big199680), 216 ) 217 } 218 gas.Mul(gas, math.BigMax(adjExpLen, big1)) 219 gas.Div(gas, new(big.Int).SetUint64(params.ModExpQuadCoeffDiv)) 220 221 if gas.BitLen() > 64 { 222 return math.MaxUint64 223 } 224 return gas.Uint64() 225 } 226 227 func (c *bigModExp) Run(input []byte) ([]byte, error) { 228 var ( 229 baseLen = new(big.Int).SetBytes(getData(input, 0, 32)).Uint64() 230 expLen = new(big.Int).SetBytes(getData(input, 32, 32)).Uint64() 231 modLen = new(big.Int).SetBytes(getData(input, 64, 32)).Uint64() 232 ) 233 if len(input) > 96 { 234 input = input[96:] 235 } else { 236 input = input[:0] 237 } 238 // Handle a special case when both the base and mod length is zero 239 if baseLen == 0 && modLen == 0 { 240 return []byte{}, nil 241 } 242 // Retrieve the operands and execute the exponentiation 243 var ( 244 base = new(big.Int).SetBytes(getData(input, 0, baseLen)) 245 exp = new(big.Int).SetBytes(getData(input, baseLen, expLen)) 246 mod = new(big.Int).SetBytes(getData(input, baseLen+expLen, modLen)) 247 ) 248 if mod.BitLen() == 0 { 249 // Modulo 0 is undefined, return zero 250 return common.LeftPadBytes([]byte{}, int(modLen)), nil 251 } 252 return common.LeftPadBytes(base.Exp(base, exp, mod).Bytes(), int(modLen)), nil 253 } 254 255 // newCurvePoint unmarshals a binary blob into a bn256 elliptic curve point, 256 // returning it, or an error if the point is invalid. 257 func newCurvePoint(blob []byte) (*bn256.G1, error) { 258 p := new(bn256.G1) 259 if _, err := p.Unmarshal(blob); err != nil { 260 return nil, err 261 } 262 return p, nil 263 } 264 265 // newTwistPoint unmarshals a binary blob into a bn256 elliptic curve point, 266 // returning it, or an error if the point is invalid. 267 func newTwistPoint(blob []byte) (*bn256.G2, error) { 268 p := new(bn256.G2) 269 if _, err := p.Unmarshal(blob); err != nil { 270 return nil, err 271 } 272 return p, nil 273 } 274 275 // bn256Add implements a native elliptic curve point addition. 276 type bn256Add struct{} 277 278 // RequiredGas returns the gas required to execute the pre-compiled contract. 279 func (c *bn256Add) RequiredGas(input []byte) uint64 { 280 return params.Bn256AddGas 281 } 282 283 func (c *bn256Add) Run(input []byte) ([]byte, error) { 284 x, err := newCurvePoint(getData(input, 0, 64)) 285 if err != nil { 286 return nil, err 287 } 288 y, err := newCurvePoint(getData(input, 64, 64)) 289 if err != nil { 290 return nil, err 291 } 292 res := new(bn256.G1) 293 res.Add(x, y) 294 return res.Marshal(), nil 295 } 296 297 // bn256ScalarMul implements a native elliptic curve scalar multiplication. 298 type bn256ScalarMul struct{} 299 300 // RequiredGas returns the gas required to execute the pre-compiled contract. 301 func (c *bn256ScalarMul) RequiredGas(input []byte) uint64 { 302 return params.Bn256ScalarMulGas 303 } 304 305 func (c *bn256ScalarMul) Run(input []byte) ([]byte, error) { 306 p, err := newCurvePoint(getData(input, 0, 64)) 307 if err != nil { 308 return nil, err 309 } 310 res := new(bn256.G1) 311 res.ScalarMult(p, new(big.Int).SetBytes(getData(input, 64, 32))) 312 return res.Marshal(), nil 313 } 314 315 var ( 316 // true32Byte is returned if the bn256 pairing check succeeds. 317 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} 318 319 // false32Byte is returned if the bn256 pairing check fails. 320 false32Byte = make([]byte, 32) 321 322 // errBadPairingInput is returned if the bn256 pairing input is invalid. 323 errBadPairingInput = errors.New("bad elliptic curve pairing size") 324 ) 325 326 // bn256Pairing implements a pairing pre-compile for the bn256 curve 327 type bn256Pairing struct{} 328 329 // RequiredGas returns the gas required to execute the pre-compiled contract. 330 func (c *bn256Pairing) RequiredGas(input []byte) uint64 { 331 return params.Bn256PairingBaseGas + uint64(len(input)/192)*params.Bn256PairingPerPointGas 332 } 333 334 func (c *bn256Pairing) Run(input []byte) ([]byte, error) { 335 // Handle some corner cases cheaply 336 if len(input)%192 > 0 { 337 return nil, errBadPairingInput 338 } 339 // Convert the input into a set of coordinates 340 var ( 341 cs []*bn256.G1 342 ts []*bn256.G2 343 ) 344 for i := 0; i < len(input); i += 192 { 345 c, err := newCurvePoint(input[i : i+64]) 346 if err != nil { 347 return nil, err 348 } 349 t, err := newTwistPoint(input[i+64 : i+192]) 350 if err != nil { 351 return nil, err 352 } 353 cs = append(cs, c) 354 ts = append(ts, t) 355 } 356 // Execute the pairing checks and return the results 357 if bn256.PairingCheck(cs, ts) { 358 return true32Byte, nil 359 } 360 return false32Byte, nil 361 }