github.com/ethereum/go-ethereum@v1.16.1/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 "encoding/binary" 22 "errors" 23 "fmt" 24 "maps" 25 "math" 26 "math/big" 27 28 "github.com/consensys/gnark-crypto/ecc" 29 bls12381 "github.com/consensys/gnark-crypto/ecc/bls12-381" 30 "github.com/consensys/gnark-crypto/ecc/bls12-381/fp" 31 "github.com/consensys/gnark-crypto/ecc/bls12-381/fr" 32 "github.com/ethereum/go-ethereum/common" 33 "github.com/ethereum/go-ethereum/core/tracing" 34 "github.com/ethereum/go-ethereum/crypto" 35 "github.com/ethereum/go-ethereum/crypto/blake2b" 36 "github.com/ethereum/go-ethereum/crypto/bn256" 37 "github.com/ethereum/go-ethereum/crypto/kzg4844" 38 "github.com/ethereum/go-ethereum/params" 39 "golang.org/x/crypto/ripemd160" 40 ) 41 42 // PrecompiledContract is the basic interface for native Go contracts. The implementation 43 // requires a deterministic gas count based on the input size of the Run method of the 44 // contract. 45 type PrecompiledContract interface { 46 RequiredGas(input []byte) uint64 // RequiredPrice calculates the contract gas use 47 Run(input []byte) ([]byte, error) // Run runs the precompiled contract 48 } 49 50 // PrecompiledContracts contains the precompiled contracts supported at the given fork. 51 type PrecompiledContracts map[common.Address]PrecompiledContract 52 53 // PrecompiledContractsHomestead contains the default set of pre-compiled Ethereum 54 // contracts used in the Frontier and Homestead releases. 55 var PrecompiledContractsHomestead = PrecompiledContracts{ 56 common.BytesToAddress([]byte{0x1}): &ecrecover{}, 57 common.BytesToAddress([]byte{0x2}): &sha256hash{}, 58 common.BytesToAddress([]byte{0x3}): &ripemd160hash{}, 59 common.BytesToAddress([]byte{0x4}): &dataCopy{}, 60 } 61 62 // PrecompiledContractsByzantium contains the default set of pre-compiled Ethereum 63 // contracts used in the Byzantium release. 64 var PrecompiledContractsByzantium = PrecompiledContracts{ 65 common.BytesToAddress([]byte{0x1}): &ecrecover{}, 66 common.BytesToAddress([]byte{0x2}): &sha256hash{}, 67 common.BytesToAddress([]byte{0x3}): &ripemd160hash{}, 68 common.BytesToAddress([]byte{0x4}): &dataCopy{}, 69 common.BytesToAddress([]byte{0x5}): &bigModExp{eip2565: false, eip7823: false, eip7883: false}, 70 common.BytesToAddress([]byte{0x6}): &bn256AddByzantium{}, 71 common.BytesToAddress([]byte{0x7}): &bn256ScalarMulByzantium{}, 72 common.BytesToAddress([]byte{0x8}): &bn256PairingByzantium{}, 73 } 74 75 // PrecompiledContractsIstanbul contains the default set of pre-compiled Ethereum 76 // contracts used in the Istanbul release. 77 var PrecompiledContractsIstanbul = PrecompiledContracts{ 78 common.BytesToAddress([]byte{0x1}): &ecrecover{}, 79 common.BytesToAddress([]byte{0x2}): &sha256hash{}, 80 common.BytesToAddress([]byte{0x3}): &ripemd160hash{}, 81 common.BytesToAddress([]byte{0x4}): &dataCopy{}, 82 common.BytesToAddress([]byte{0x5}): &bigModExp{eip2565: false, eip7823: false, eip7883: false}, 83 common.BytesToAddress([]byte{0x6}): &bn256AddIstanbul{}, 84 common.BytesToAddress([]byte{0x7}): &bn256ScalarMulIstanbul{}, 85 common.BytesToAddress([]byte{0x8}): &bn256PairingIstanbul{}, 86 common.BytesToAddress([]byte{0x9}): &blake2F{}, 87 } 88 89 // PrecompiledContractsBerlin contains the default set of pre-compiled Ethereum 90 // contracts used in the Berlin release. 91 var PrecompiledContractsBerlin = PrecompiledContracts{ 92 common.BytesToAddress([]byte{0x1}): &ecrecover{}, 93 common.BytesToAddress([]byte{0x2}): &sha256hash{}, 94 common.BytesToAddress([]byte{0x3}): &ripemd160hash{}, 95 common.BytesToAddress([]byte{0x4}): &dataCopy{}, 96 common.BytesToAddress([]byte{0x5}): &bigModExp{eip2565: true, eip7823: false, eip7883: false}, 97 common.BytesToAddress([]byte{0x6}): &bn256AddIstanbul{}, 98 common.BytesToAddress([]byte{0x7}): &bn256ScalarMulIstanbul{}, 99 common.BytesToAddress([]byte{0x8}): &bn256PairingIstanbul{}, 100 common.BytesToAddress([]byte{0x9}): &blake2F{}, 101 } 102 103 // PrecompiledContractsCancun contains the default set of pre-compiled Ethereum 104 // contracts used in the Cancun release. 105 var PrecompiledContractsCancun = PrecompiledContracts{ 106 common.BytesToAddress([]byte{0x1}): &ecrecover{}, 107 common.BytesToAddress([]byte{0x2}): &sha256hash{}, 108 common.BytesToAddress([]byte{0x3}): &ripemd160hash{}, 109 common.BytesToAddress([]byte{0x4}): &dataCopy{}, 110 common.BytesToAddress([]byte{0x5}): &bigModExp{eip2565: true, eip7823: false, eip7883: false}, 111 common.BytesToAddress([]byte{0x6}): &bn256AddIstanbul{}, 112 common.BytesToAddress([]byte{0x7}): &bn256ScalarMulIstanbul{}, 113 common.BytesToAddress([]byte{0x8}): &bn256PairingIstanbul{}, 114 common.BytesToAddress([]byte{0x9}): &blake2F{}, 115 common.BytesToAddress([]byte{0xa}): &kzgPointEvaluation{}, 116 } 117 118 // PrecompiledContractsPrague contains the set of pre-compiled Ethereum 119 // contracts used in the Prague release. 120 var PrecompiledContractsPrague = PrecompiledContracts{ 121 common.BytesToAddress([]byte{0x01}): &ecrecover{}, 122 common.BytesToAddress([]byte{0x02}): &sha256hash{}, 123 common.BytesToAddress([]byte{0x03}): &ripemd160hash{}, 124 common.BytesToAddress([]byte{0x04}): &dataCopy{}, 125 common.BytesToAddress([]byte{0x05}): &bigModExp{eip2565: true, eip7823: false, eip7883: false}, 126 common.BytesToAddress([]byte{0x06}): &bn256AddIstanbul{}, 127 common.BytesToAddress([]byte{0x07}): &bn256ScalarMulIstanbul{}, 128 common.BytesToAddress([]byte{0x08}): &bn256PairingIstanbul{}, 129 common.BytesToAddress([]byte{0x09}): &blake2F{}, 130 common.BytesToAddress([]byte{0x0a}): &kzgPointEvaluation{}, 131 common.BytesToAddress([]byte{0x0b}): &bls12381G1Add{}, 132 common.BytesToAddress([]byte{0x0c}): &bls12381G1MultiExp{}, 133 common.BytesToAddress([]byte{0x0d}): &bls12381G2Add{}, 134 common.BytesToAddress([]byte{0x0e}): &bls12381G2MultiExp{}, 135 common.BytesToAddress([]byte{0x0f}): &bls12381Pairing{}, 136 common.BytesToAddress([]byte{0x10}): &bls12381MapG1{}, 137 common.BytesToAddress([]byte{0x11}): &bls12381MapG2{}, 138 } 139 140 var PrecompiledContractsBLS = PrecompiledContractsPrague 141 142 var PrecompiledContractsVerkle = PrecompiledContractsBerlin 143 144 // PrecompiledContractsOsaka contains the set of pre-compiled Ethereum 145 // contracts used in the Osaka release. 146 var PrecompiledContractsOsaka = PrecompiledContracts{ 147 common.BytesToAddress([]byte{0x01}): &ecrecover{}, 148 common.BytesToAddress([]byte{0x02}): &sha256hash{}, 149 common.BytesToAddress([]byte{0x03}): &ripemd160hash{}, 150 common.BytesToAddress([]byte{0x04}): &dataCopy{}, 151 common.BytesToAddress([]byte{0x05}): &bigModExp{eip2565: true, eip7823: true, eip7883: true}, 152 common.BytesToAddress([]byte{0x06}): &bn256AddIstanbul{}, 153 common.BytesToAddress([]byte{0x07}): &bn256ScalarMulIstanbul{}, 154 common.BytesToAddress([]byte{0x08}): &bn256PairingIstanbul{}, 155 common.BytesToAddress([]byte{0x09}): &blake2F{}, 156 common.BytesToAddress([]byte{0x0a}): &kzgPointEvaluation{}, 157 common.BytesToAddress([]byte{0x0b}): &bls12381G1Add{}, 158 common.BytesToAddress([]byte{0x0c}): &bls12381G1MultiExp{}, 159 common.BytesToAddress([]byte{0x0d}): &bls12381G2Add{}, 160 common.BytesToAddress([]byte{0x0e}): &bls12381G2MultiExp{}, 161 common.BytesToAddress([]byte{0x0f}): &bls12381Pairing{}, 162 common.BytesToAddress([]byte{0x10}): &bls12381MapG1{}, 163 common.BytesToAddress([]byte{0x11}): &bls12381MapG2{}, 164 } 165 166 var ( 167 PrecompiledAddressesOsaka []common.Address 168 PrecompiledAddressesPrague []common.Address 169 PrecompiledAddressesCancun []common.Address 170 PrecompiledAddressesBerlin []common.Address 171 PrecompiledAddressesIstanbul []common.Address 172 PrecompiledAddressesByzantium []common.Address 173 PrecompiledAddressesHomestead []common.Address 174 ) 175 176 func init() { 177 for k := range PrecompiledContractsHomestead { 178 PrecompiledAddressesHomestead = append(PrecompiledAddressesHomestead, k) 179 } 180 for k := range PrecompiledContractsByzantium { 181 PrecompiledAddressesByzantium = append(PrecompiledAddressesByzantium, k) 182 } 183 for k := range PrecompiledContractsIstanbul { 184 PrecompiledAddressesIstanbul = append(PrecompiledAddressesIstanbul, k) 185 } 186 for k := range PrecompiledContractsBerlin { 187 PrecompiledAddressesBerlin = append(PrecompiledAddressesBerlin, k) 188 } 189 for k := range PrecompiledContractsCancun { 190 PrecompiledAddressesCancun = append(PrecompiledAddressesCancun, k) 191 } 192 for k := range PrecompiledContractsPrague { 193 PrecompiledAddressesPrague = append(PrecompiledAddressesPrague, k) 194 } 195 for k := range PrecompiledContractsOsaka { 196 PrecompiledAddressesOsaka = append(PrecompiledAddressesOsaka, k) 197 } 198 } 199 200 func activePrecompiledContracts(rules params.Rules) PrecompiledContracts { 201 switch { 202 case rules.IsVerkle: 203 return PrecompiledContractsVerkle 204 case rules.IsOsaka: 205 return PrecompiledContractsOsaka 206 case rules.IsPrague: 207 return PrecompiledContractsPrague 208 case rules.IsCancun: 209 return PrecompiledContractsCancun 210 case rules.IsBerlin: 211 return PrecompiledContractsBerlin 212 case rules.IsIstanbul: 213 return PrecompiledContractsIstanbul 214 case rules.IsByzantium: 215 return PrecompiledContractsByzantium 216 default: 217 return PrecompiledContractsHomestead 218 } 219 } 220 221 // ActivePrecompiledContracts returns a copy of precompiled contracts enabled with the current configuration. 222 func ActivePrecompiledContracts(rules params.Rules) PrecompiledContracts { 223 return maps.Clone(activePrecompiledContracts(rules)) 224 } 225 226 // ActivePrecompiles returns the precompile addresses enabled with the current configuration. 227 func ActivePrecompiles(rules params.Rules) []common.Address { 228 switch { 229 case rules.IsOsaka: 230 return PrecompiledAddressesOsaka 231 case rules.IsPrague: 232 return PrecompiledAddressesPrague 233 case rules.IsCancun: 234 return PrecompiledAddressesCancun 235 case rules.IsBerlin: 236 return PrecompiledAddressesBerlin 237 case rules.IsIstanbul: 238 return PrecompiledAddressesIstanbul 239 case rules.IsByzantium: 240 return PrecompiledAddressesByzantium 241 default: 242 return PrecompiledAddressesHomestead 243 } 244 } 245 246 // RunPrecompiledContract runs and evaluates the output of a precompiled contract. 247 // It returns 248 // - the returned bytes, 249 // - the _remaining_ gas, 250 // - any error that occurred 251 func RunPrecompiledContract(p PrecompiledContract, input []byte, suppliedGas uint64, logger *tracing.Hooks) (ret []byte, remainingGas uint64, err error) { 252 gasCost := p.RequiredGas(input) 253 if suppliedGas < gasCost { 254 return nil, 0, ErrOutOfGas 255 } 256 if logger != nil && logger.OnGasChange != nil { 257 logger.OnGasChange(suppliedGas, suppliedGas-gasCost, tracing.GasChangeCallPrecompiledContract) 258 } 259 suppliedGas -= gasCost 260 output, err := p.Run(input) 261 return output, suppliedGas, err 262 } 263 264 // ecrecover implemented as a native contract. 265 type ecrecover struct{} 266 267 func (c *ecrecover) RequiredGas(input []byte) uint64 { 268 return params.EcrecoverGas 269 } 270 271 func (c *ecrecover) Run(input []byte) ([]byte, error) { 272 const ecRecoverInputLength = 128 273 274 input = common.RightPadBytes(input, ecRecoverInputLength) 275 // "input" is (hash, v, r, s), each 32 bytes 276 // but for ecrecover we want (r, s, v) 277 278 r := new(big.Int).SetBytes(input[64:96]) 279 s := new(big.Int).SetBytes(input[96:128]) 280 v := input[63] - 27 281 282 // tighter sig s values input homestead only apply to tx sigs 283 if !allZero(input[32:63]) || !crypto.ValidateSignatureValues(v, r, s, false) { 284 return nil, nil 285 } 286 // We must make sure not to modify the 'input', so placing the 'v' along with 287 // the signature needs to be done on a new allocation 288 sig := make([]byte, 65) 289 copy(sig, input[64:128]) 290 sig[64] = v 291 // v needs to be at the end for libsecp256k1 292 pubKey, err := crypto.Ecrecover(input[:32], sig) 293 // make sure the public key is a valid one 294 if err != nil { 295 return nil, nil 296 } 297 298 // the first byte of pubkey is bitcoin heritage 299 return common.LeftPadBytes(crypto.Keccak256(pubKey[1:])[12:], 32), nil 300 } 301 302 // SHA256 implemented as a native contract. 303 type sha256hash struct{} 304 305 // RequiredGas returns the gas required to execute the pre-compiled contract. 306 // 307 // This method does not require any overflow checking as the input size gas costs 308 // required for anything significant is so high it's impossible to pay for. 309 func (c *sha256hash) RequiredGas(input []byte) uint64 { 310 return uint64(len(input)+31)/32*params.Sha256PerWordGas + params.Sha256BaseGas 311 } 312 func (c *sha256hash) Run(input []byte) ([]byte, error) { 313 h := sha256.Sum256(input) 314 return h[:], nil 315 } 316 317 // RIPEMD160 implemented as a native contract. 318 type ripemd160hash struct{} 319 320 // RequiredGas returns the gas required to execute the pre-compiled contract. 321 // 322 // This method does not require any overflow checking as the input size gas costs 323 // required for anything significant is so high it's impossible to pay for. 324 func (c *ripemd160hash) RequiredGas(input []byte) uint64 { 325 return uint64(len(input)+31)/32*params.Ripemd160PerWordGas + params.Ripemd160BaseGas 326 } 327 func (c *ripemd160hash) Run(input []byte) ([]byte, error) { 328 ripemd := ripemd160.New() 329 ripemd.Write(input) 330 return common.LeftPadBytes(ripemd.Sum(nil), 32), nil 331 } 332 333 // data copy implemented as a native contract. 334 type dataCopy struct{} 335 336 // RequiredGas returns the gas required to execute the pre-compiled contract. 337 // 338 // This method does not require any overflow checking as the input size gas costs 339 // required for anything significant is so high it's impossible to pay for. 340 func (c *dataCopy) RequiredGas(input []byte) uint64 { 341 return uint64(len(input)+31)/32*params.IdentityPerWordGas + params.IdentityBaseGas 342 } 343 func (c *dataCopy) Run(in []byte) ([]byte, error) { 344 return common.CopyBytes(in), nil 345 } 346 347 // bigModExp implements a native big integer exponential modular operation. 348 type bigModExp struct { 349 eip2565 bool 350 eip7823 bool 351 eip7883 bool 352 } 353 354 var ( 355 big1 = big.NewInt(1) 356 big3 = big.NewInt(3) 357 big7 = big.NewInt(7) 358 big20 = big.NewInt(20) 359 big32 = big.NewInt(32) 360 big64 = big.NewInt(64) 361 big96 = big.NewInt(96) 362 big480 = big.NewInt(480) 363 big1024 = big.NewInt(1024) 364 big3072 = big.NewInt(3072) 365 big199680 = big.NewInt(199680) 366 ) 367 368 // modexpMultComplexity implements bigModexp multComplexity formula, as defined in EIP-198 369 // 370 // def mult_complexity(x): 371 // if x <= 64: return x ** 2 372 // elif x <= 1024: return x ** 2 // 4 + 96 * x - 3072 373 // else: return x ** 2 // 16 + 480 * x - 199680 374 // 375 // where is x is max(length_of_MODULUS, length_of_BASE) 376 func modexpMultComplexity(x *big.Int) *big.Int { 377 switch { 378 case x.Cmp(big64) <= 0: 379 x.Mul(x, x) // x ** 2 380 case x.Cmp(big1024) <= 0: 381 // (x ** 2 // 4 ) + ( 96 * x - 3072) 382 x = new(big.Int).Add( 383 new(big.Int).Rsh(new(big.Int).Mul(x, x), 2), 384 new(big.Int).Sub(new(big.Int).Mul(big96, x), big3072), 385 ) 386 default: 387 // (x ** 2 // 16) + (480 * x - 199680) 388 x = new(big.Int).Add( 389 new(big.Int).Rsh(new(big.Int).Mul(x, x), 4), 390 new(big.Int).Sub(new(big.Int).Mul(big480, x), big199680), 391 ) 392 } 393 return x 394 } 395 396 // RequiredGas returns the gas required to execute the pre-compiled contract. 397 func (c *bigModExp) RequiredGas(input []byte) uint64 { 398 var ( 399 baseLen = new(big.Int).SetBytes(getData(input, 0, 32)) 400 expLen = new(big.Int).SetBytes(getData(input, 32, 32)) 401 modLen = new(big.Int).SetBytes(getData(input, 64, 32)) 402 ) 403 if len(input) > 96 { 404 input = input[96:] 405 } else { 406 input = input[:0] 407 } 408 // Retrieve the head 32 bytes of exp for the adjusted exponent length 409 var expHead *big.Int 410 if big.NewInt(int64(len(input))).Cmp(baseLen) <= 0 { 411 expHead = new(big.Int) 412 } else { 413 if expLen.Cmp(big32) > 0 { 414 expHead = new(big.Int).SetBytes(getData(input, baseLen.Uint64(), 32)) 415 } else { 416 expHead = new(big.Int).SetBytes(getData(input, baseLen.Uint64(), expLen.Uint64())) 417 } 418 } 419 // Calculate the adjusted exponent length 420 var msb int 421 if bitlen := expHead.BitLen(); bitlen > 0 { 422 msb = bitlen - 1 423 } 424 adjExpLen := new(big.Int) 425 if expLen.Cmp(big32) > 0 { 426 adjExpLen.Sub(expLen, big32) 427 if c.eip7883 { 428 adjExpLen.Lsh(adjExpLen, 4) 429 } else { 430 adjExpLen.Lsh(adjExpLen, 3) 431 } 432 } 433 adjExpLen.Add(adjExpLen, big.NewInt(int64(msb))) 434 // Calculate the gas cost of the operation 435 gas := new(big.Int) 436 if modLen.Cmp(baseLen) < 0 { 437 gas.Set(baseLen) 438 } else { 439 gas.Set(modLen) 440 } 441 442 maxLenOver32 := gas.Cmp(big32) > 0 443 if c.eip2565 { 444 // EIP-2565 (Berlin fork) has three changes: 445 // 446 // 1. Different multComplexity (inlined here) 447 // in EIP-2565 (https://eips.ethereum.org/EIPS/eip-2565): 448 // 449 // def mult_complexity(x): 450 // ceiling(x/8)^2 451 // 452 // where is x is max(length_of_MODULUS, length_of_BASE) 453 gas.Add(gas, big7) 454 gas.Rsh(gas, 3) 455 gas.Mul(gas, gas) 456 457 var minPrice uint64 = 200 458 if c.eip7883 { 459 minPrice = 500 460 if maxLenOver32 { 461 gas.Add(gas, gas) 462 } else { 463 gas = big.NewInt(16) 464 } 465 } 466 467 if adjExpLen.Cmp(big1) > 0 { 468 gas.Mul(gas, adjExpLen) 469 } 470 // 2. Different divisor (`GQUADDIVISOR`) (3) 471 gas.Div(gas, big3) 472 if gas.BitLen() > 64 { 473 return math.MaxUint64 474 } 475 return max(minPrice, gas.Uint64()) 476 } 477 478 // Pre-Berlin logic. 479 gas = modexpMultComplexity(gas) 480 if adjExpLen.Cmp(big1) > 0 { 481 gas.Mul(gas, adjExpLen) 482 } 483 gas.Div(gas, big20) 484 if gas.BitLen() > 64 { 485 return math.MaxUint64 486 } 487 return gas.Uint64() 488 } 489 490 func (c *bigModExp) Run(input []byte) ([]byte, error) { 491 var ( 492 baseLen = new(big.Int).SetBytes(getData(input, 0, 32)).Uint64() 493 expLen = new(big.Int).SetBytes(getData(input, 32, 32)).Uint64() 494 modLen = new(big.Int).SetBytes(getData(input, 64, 32)).Uint64() 495 ) 496 if len(input) > 96 { 497 input = input[96:] 498 } else { 499 input = input[:0] 500 } 501 // Handle a special case when both the base and mod length is zero 502 if baseLen == 0 && modLen == 0 { 503 return []byte{}, nil 504 } 505 // enforce size cap for inputs 506 if c.eip7823 && max(baseLen, expLen, modLen) > 1024 { 507 return nil, fmt.Errorf("one or more of base/exponent/modulus length exceeded 1024 bytes") 508 } 509 // Retrieve the operands and execute the exponentiation 510 var ( 511 base = new(big.Int).SetBytes(getData(input, 0, baseLen)) 512 exp = new(big.Int).SetBytes(getData(input, baseLen, expLen)) 513 mod = new(big.Int).SetBytes(getData(input, baseLen+expLen, modLen)) 514 v []byte 515 ) 516 switch { 517 case mod.BitLen() == 0: 518 // Modulo 0 is undefined, return zero 519 return common.LeftPadBytes([]byte{}, int(modLen)), nil 520 case base.BitLen() == 1: // a bit length of 1 means it's 1 (or -1). 521 //If base == 1, then we can just return base % mod (if mod >= 1, which it is) 522 v = base.Mod(base, mod).Bytes() 523 default: 524 v = base.Exp(base, exp, mod).Bytes() 525 } 526 return common.LeftPadBytes(v, int(modLen)), nil 527 } 528 529 // newCurvePoint unmarshals a binary blob into a bn256 elliptic curve point, 530 // returning it, or an error if the point is invalid. 531 func newCurvePoint(blob []byte) (*bn256.G1, error) { 532 p := new(bn256.G1) 533 if _, err := p.Unmarshal(blob); err != nil { 534 return nil, err 535 } 536 return p, nil 537 } 538 539 // newTwistPoint unmarshals a binary blob into a bn256 elliptic curve point, 540 // returning it, or an error if the point is invalid. 541 func newTwistPoint(blob []byte) (*bn256.G2, error) { 542 p := new(bn256.G2) 543 if _, err := p.Unmarshal(blob); err != nil { 544 return nil, err 545 } 546 return p, nil 547 } 548 549 // runBn256Add implements the Bn256Add precompile, referenced by both 550 // Byzantium and Istanbul operations. 551 func runBn256Add(input []byte) ([]byte, error) { 552 x, err := newCurvePoint(getData(input, 0, 64)) 553 if err != nil { 554 return nil, err 555 } 556 y, err := newCurvePoint(getData(input, 64, 64)) 557 if err != nil { 558 return nil, err 559 } 560 res := new(bn256.G1) 561 res.Add(x, y) 562 return res.Marshal(), nil 563 } 564 565 // bn256AddIstanbul implements a native elliptic curve point addition conforming to 566 // Istanbul consensus rules. 567 type bn256AddIstanbul struct{} 568 569 // RequiredGas returns the gas required to execute the pre-compiled contract. 570 func (c *bn256AddIstanbul) RequiredGas(input []byte) uint64 { 571 return params.Bn256AddGasIstanbul 572 } 573 574 func (c *bn256AddIstanbul) Run(input []byte) ([]byte, error) { 575 return runBn256Add(input) 576 } 577 578 // bn256AddByzantium implements a native elliptic curve point addition 579 // conforming to Byzantium consensus rules. 580 type bn256AddByzantium struct{} 581 582 // RequiredGas returns the gas required to execute the pre-compiled contract. 583 func (c *bn256AddByzantium) RequiredGas(input []byte) uint64 { 584 return params.Bn256AddGasByzantium 585 } 586 587 func (c *bn256AddByzantium) Run(input []byte) ([]byte, error) { 588 return runBn256Add(input) 589 } 590 591 // runBn256ScalarMul implements the Bn256ScalarMul precompile, referenced by 592 // both Byzantium and Istanbul operations. 593 func runBn256ScalarMul(input []byte) ([]byte, error) { 594 p, err := newCurvePoint(getData(input, 0, 64)) 595 if err != nil { 596 return nil, err 597 } 598 res := new(bn256.G1) 599 res.ScalarMult(p, new(big.Int).SetBytes(getData(input, 64, 32))) 600 return res.Marshal(), nil 601 } 602 603 // bn256ScalarMulIstanbul implements a native elliptic curve scalar 604 // multiplication conforming to Istanbul consensus rules. 605 type bn256ScalarMulIstanbul struct{} 606 607 // RequiredGas returns the gas required to execute the pre-compiled contract. 608 func (c *bn256ScalarMulIstanbul) RequiredGas(input []byte) uint64 { 609 return params.Bn256ScalarMulGasIstanbul 610 } 611 612 func (c *bn256ScalarMulIstanbul) Run(input []byte) ([]byte, error) { 613 return runBn256ScalarMul(input) 614 } 615 616 // bn256ScalarMulByzantium implements a native elliptic curve scalar 617 // multiplication conforming to Byzantium consensus rules. 618 type bn256ScalarMulByzantium struct{} 619 620 // RequiredGas returns the gas required to execute the pre-compiled contract. 621 func (c *bn256ScalarMulByzantium) RequiredGas(input []byte) uint64 { 622 return params.Bn256ScalarMulGasByzantium 623 } 624 625 func (c *bn256ScalarMulByzantium) Run(input []byte) ([]byte, error) { 626 return runBn256ScalarMul(input) 627 } 628 629 var ( 630 // true32Byte is returned if the bn256 pairing check succeeds. 631 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} 632 633 // false32Byte is returned if the bn256 pairing check fails. 634 false32Byte = make([]byte, 32) 635 636 // errBadPairingInput is returned if the bn256 pairing input is invalid. 637 errBadPairingInput = errors.New("bad elliptic curve pairing size") 638 ) 639 640 // runBn256Pairing implements the Bn256Pairing precompile, referenced by both 641 // Byzantium and Istanbul operations. 642 func runBn256Pairing(input []byte) ([]byte, error) { 643 // Handle some corner cases cheaply 644 if len(input)%192 > 0 { 645 return nil, errBadPairingInput 646 } 647 // Convert the input into a set of coordinates 648 var ( 649 cs []*bn256.G1 650 ts []*bn256.G2 651 ) 652 for i := 0; i < len(input); i += 192 { 653 c, err := newCurvePoint(input[i : i+64]) 654 if err != nil { 655 return nil, err 656 } 657 t, err := newTwistPoint(input[i+64 : i+192]) 658 if err != nil { 659 return nil, err 660 } 661 cs = append(cs, c) 662 ts = append(ts, t) 663 } 664 // Execute the pairing checks and return the results 665 if bn256.PairingCheck(cs, ts) { 666 return true32Byte, nil 667 } 668 return false32Byte, nil 669 } 670 671 // bn256PairingIstanbul implements a pairing pre-compile for the bn256 curve 672 // conforming to Istanbul consensus rules. 673 type bn256PairingIstanbul struct{} 674 675 // RequiredGas returns the gas required to execute the pre-compiled contract. 676 func (c *bn256PairingIstanbul) RequiredGas(input []byte) uint64 { 677 return params.Bn256PairingBaseGasIstanbul + uint64(len(input)/192)*params.Bn256PairingPerPointGasIstanbul 678 } 679 680 func (c *bn256PairingIstanbul) Run(input []byte) ([]byte, error) { 681 return runBn256Pairing(input) 682 } 683 684 // bn256PairingByzantium implements a pairing pre-compile for the bn256 curve 685 // conforming to Byzantium consensus rules. 686 type bn256PairingByzantium struct{} 687 688 // RequiredGas returns the gas required to execute the pre-compiled contract. 689 func (c *bn256PairingByzantium) RequiredGas(input []byte) uint64 { 690 return params.Bn256PairingBaseGasByzantium + uint64(len(input)/192)*params.Bn256PairingPerPointGasByzantium 691 } 692 693 func (c *bn256PairingByzantium) Run(input []byte) ([]byte, error) { 694 return runBn256Pairing(input) 695 } 696 697 type blake2F struct{} 698 699 func (c *blake2F) RequiredGas(input []byte) uint64 { 700 // If the input is malformed, we can't calculate the gas, return 0 and let the 701 // actual call choke and fault. 702 if len(input) != blake2FInputLength { 703 return 0 704 } 705 return uint64(binary.BigEndian.Uint32(input[0:4])) 706 } 707 708 const ( 709 blake2FInputLength = 213 710 blake2FFinalBlockBytes = byte(1) 711 blake2FNonFinalBlockBytes = byte(0) 712 ) 713 714 var ( 715 errBlake2FInvalidInputLength = errors.New("invalid input length") 716 errBlake2FInvalidFinalFlag = errors.New("invalid final flag") 717 ) 718 719 func (c *blake2F) Run(input []byte) ([]byte, error) { 720 // Make sure the input is valid (correct length and final flag) 721 if len(input) != blake2FInputLength { 722 return nil, errBlake2FInvalidInputLength 723 } 724 if input[212] != blake2FNonFinalBlockBytes && input[212] != blake2FFinalBlockBytes { 725 return nil, errBlake2FInvalidFinalFlag 726 } 727 // Parse the input into the Blake2b call parameters 728 var ( 729 rounds = binary.BigEndian.Uint32(input[0:4]) 730 final = input[212] == blake2FFinalBlockBytes 731 732 h [8]uint64 733 m [16]uint64 734 t [2]uint64 735 ) 736 for i := 0; i < 8; i++ { 737 offset := 4 + i*8 738 h[i] = binary.LittleEndian.Uint64(input[offset : offset+8]) 739 } 740 for i := 0; i < 16; i++ { 741 offset := 68 + i*8 742 m[i] = binary.LittleEndian.Uint64(input[offset : offset+8]) 743 } 744 t[0] = binary.LittleEndian.Uint64(input[196:204]) 745 t[1] = binary.LittleEndian.Uint64(input[204:212]) 746 747 // Execute the compression function, extract and return the result 748 blake2b.F(&h, m, t, final, rounds) 749 750 output := make([]byte, 64) 751 for i := 0; i < 8; i++ { 752 offset := i * 8 753 binary.LittleEndian.PutUint64(output[offset:offset+8], h[i]) 754 } 755 return output, nil 756 } 757 758 var ( 759 errBLS12381InvalidInputLength = errors.New("invalid input length") 760 errBLS12381InvalidFieldElementTopBytes = errors.New("invalid field element top bytes") 761 errBLS12381G1PointSubgroup = errors.New("g1 point is not on correct subgroup") 762 errBLS12381G2PointSubgroup = errors.New("g2 point is not on correct subgroup") 763 ) 764 765 // bls12381G1Add implements EIP-2537 G1Add precompile. 766 type bls12381G1Add struct{} 767 768 // RequiredGas returns the gas required to execute the pre-compiled contract. 769 func (c *bls12381G1Add) RequiredGas(input []byte) uint64 { 770 return params.Bls12381G1AddGas 771 } 772 773 func (c *bls12381G1Add) Run(input []byte) ([]byte, error) { 774 // Implements EIP-2537 G1Add precompile. 775 // > G1 addition call expects `256` bytes as an input that is interpreted as byte concatenation of two G1 points (`128` bytes each). 776 // > Output is an encoding of addition operation result - single G1 point (`128` bytes). 777 if len(input) != 256 { 778 return nil, errBLS12381InvalidInputLength 779 } 780 var err error 781 var p0, p1 *bls12381.G1Affine 782 783 // Decode G1 point p_0 784 if p0, err = decodePointG1(input[:128]); err != nil { 785 return nil, err 786 } 787 // Decode G1 point p_1 788 if p1, err = decodePointG1(input[128:]); err != nil { 789 return nil, err 790 } 791 792 // No need to check the subgroup here, as specified by EIP-2537 793 794 // Compute r = p_0 + p_1 795 p0.Add(p0, p1) 796 797 // Encode the G1 point result into 128 bytes 798 return encodePointG1(p0), nil 799 } 800 801 // bls12381G1MultiExp implements EIP-2537 G1MultiExp precompile. 802 type bls12381G1MultiExp struct{} 803 804 // RequiredGas returns the gas required to execute the pre-compiled contract. 805 func (c *bls12381G1MultiExp) RequiredGas(input []byte) uint64 { 806 // Calculate G1 point, scalar value pair length 807 k := len(input) / 160 808 if k == 0 { 809 // Return 0 gas for small input length 810 return 0 811 } 812 // Lookup discount value for G1 point, scalar value pair length 813 var discount uint64 814 if dLen := len(params.Bls12381G1MultiExpDiscountTable); k < dLen { 815 discount = params.Bls12381G1MultiExpDiscountTable[k-1] 816 } else { 817 discount = params.Bls12381G1MultiExpDiscountTable[dLen-1] 818 } 819 // Calculate gas and return the result 820 return (uint64(k) * params.Bls12381G1MulGas * discount) / 1000 821 } 822 823 func (c *bls12381G1MultiExp) Run(input []byte) ([]byte, error) { 824 // Implements EIP-2537 G1MultiExp precompile. 825 // G1 multiplication call expects `160*k` bytes as an input that is interpreted as byte concatenation of `k` slices each of them being a byte concatenation of encoding of G1 point (`128` bytes) and encoding of a scalar value (`32` bytes). 826 // Output is an encoding of multiexponentiation operation result - single G1 point (`128` bytes). 827 k := len(input) / 160 828 if len(input) == 0 || len(input)%160 != 0 { 829 return nil, errBLS12381InvalidInputLength 830 } 831 points := make([]bls12381.G1Affine, k) 832 scalars := make([]fr.Element, k) 833 834 // Decode point scalar pairs 835 for i := 0; i < k; i++ { 836 off := 160 * i 837 t0, t1, t2 := off, off+128, off+160 838 // Decode G1 point 839 p, err := decodePointG1(input[t0:t1]) 840 if err != nil { 841 return nil, err 842 } 843 // 'point is on curve' check already done, 844 // Here we need to apply subgroup checks. 845 if !p.IsInSubGroup() { 846 return nil, errBLS12381G1PointSubgroup 847 } 848 points[i] = *p 849 // Decode scalar value 850 scalars[i] = *new(fr.Element).SetBytes(input[t1:t2]) 851 } 852 853 // Compute r = e_0 * p_0 + e_1 * p_1 + ... + e_(k-1) * p_(k-1) 854 r := new(bls12381.G1Affine) 855 r.MultiExp(points, scalars, ecc.MultiExpConfig{}) 856 857 // Encode the G1 point to 128 bytes 858 return encodePointG1(r), nil 859 } 860 861 // bls12381G2Add implements EIP-2537 G2Add precompile. 862 type bls12381G2Add struct{} 863 864 // RequiredGas returns the gas required to execute the pre-compiled contract. 865 func (c *bls12381G2Add) RequiredGas(input []byte) uint64 { 866 return params.Bls12381G2AddGas 867 } 868 869 func (c *bls12381G2Add) Run(input []byte) ([]byte, error) { 870 // Implements EIP-2537 G2Add precompile. 871 // > G2 addition call expects `512` bytes as an input that is interpreted as byte concatenation of two G2 points (`256` bytes each). 872 // > Output is an encoding of addition operation result - single G2 point (`256` bytes). 873 if len(input) != 512 { 874 return nil, errBLS12381InvalidInputLength 875 } 876 var err error 877 var p0, p1 *bls12381.G2Affine 878 879 // Decode G2 point p_0 880 if p0, err = decodePointG2(input[:256]); err != nil { 881 return nil, err 882 } 883 // Decode G2 point p_1 884 if p1, err = decodePointG2(input[256:]); err != nil { 885 return nil, err 886 } 887 888 // No need to check the subgroup here, as specified by EIP-2537 889 890 // Compute r = p_0 + p_1 891 r := new(bls12381.G2Affine) 892 r.Add(p0, p1) 893 894 // Encode the G2 point into 256 bytes 895 return encodePointG2(r), nil 896 } 897 898 // bls12381G2MultiExp implements EIP-2537 G2MultiExp precompile. 899 type bls12381G2MultiExp struct{} 900 901 // RequiredGas returns the gas required to execute the pre-compiled contract. 902 func (c *bls12381G2MultiExp) RequiredGas(input []byte) uint64 { 903 // Calculate G2 point, scalar value pair length 904 k := len(input) / 288 905 if k == 0 { 906 // Return 0 gas for small input length 907 return 0 908 } 909 // Lookup discount value for G2 point, scalar value pair length 910 var discount uint64 911 if dLen := len(params.Bls12381G2MultiExpDiscountTable); k < dLen { 912 discount = params.Bls12381G2MultiExpDiscountTable[k-1] 913 } else { 914 discount = params.Bls12381G2MultiExpDiscountTable[dLen-1] 915 } 916 // Calculate gas and return the result 917 return (uint64(k) * params.Bls12381G2MulGas * discount) / 1000 918 } 919 920 func (c *bls12381G2MultiExp) Run(input []byte) ([]byte, error) { 921 // Implements EIP-2537 G2MultiExp precompile logic 922 // > G2 multiplication call expects `288*k` bytes as an input that is interpreted as byte concatenation of `k` slices each of them being a byte concatenation of encoding of G2 point (`256` bytes) and encoding of a scalar value (`32` bytes). 923 // > Output is an encoding of multiexponentiation operation result - single G2 point (`256` bytes). 924 k := len(input) / 288 925 if len(input) == 0 || len(input)%288 != 0 { 926 return nil, errBLS12381InvalidInputLength 927 } 928 points := make([]bls12381.G2Affine, k) 929 scalars := make([]fr.Element, k) 930 931 // Decode point scalar pairs 932 for i := 0; i < k; i++ { 933 off := 288 * i 934 t0, t1, t2 := off, off+256, off+288 935 // Decode G2 point 936 p, err := decodePointG2(input[t0:t1]) 937 if err != nil { 938 return nil, err 939 } 940 // 'point is on curve' check already done, 941 // Here we need to apply subgroup checks. 942 if !p.IsInSubGroup() { 943 return nil, errBLS12381G2PointSubgroup 944 } 945 points[i] = *p 946 // Decode scalar value 947 scalars[i] = *new(fr.Element).SetBytes(input[t1:t2]) 948 } 949 950 // Compute r = e_0 * p_0 + e_1 * p_1 + ... + e_(k-1) * p_(k-1) 951 r := new(bls12381.G2Affine) 952 r.MultiExp(points, scalars, ecc.MultiExpConfig{}) 953 954 // Encode the G2 point to 256 bytes. 955 return encodePointG2(r), nil 956 } 957 958 // bls12381Pairing implements EIP-2537 Pairing precompile. 959 type bls12381Pairing struct{} 960 961 // RequiredGas returns the gas required to execute the pre-compiled contract. 962 func (c *bls12381Pairing) RequiredGas(input []byte) uint64 { 963 return params.Bls12381PairingBaseGas + uint64(len(input)/384)*params.Bls12381PairingPerPairGas 964 } 965 966 func (c *bls12381Pairing) Run(input []byte) ([]byte, error) { 967 // Implements EIP-2537 Pairing precompile logic. 968 // > Pairing call expects `384*k` bytes as an inputs that is interpreted as byte concatenation of `k` slices. Each slice has the following structure: 969 // > - `128` bytes of G1 point encoding 970 // > - `256` bytes of G2 point encoding 971 // > Output is a `32` bytes where last single byte is `0x01` if pairing result is equal to multiplicative identity in a pairing target field and `0x00` otherwise 972 // > (which is equivalent of Big Endian encoding of Solidity values `uint256(1)` and `uin256(0)` respectively). 973 k := len(input) / 384 974 if len(input) == 0 || len(input)%384 != 0 { 975 return nil, errBLS12381InvalidInputLength 976 } 977 978 var ( 979 p []bls12381.G1Affine 980 q []bls12381.G2Affine 981 ) 982 983 // Decode pairs 984 for i := 0; i < k; i++ { 985 off := 384 * i 986 t0, t1, t2 := off, off+128, off+384 987 988 // Decode G1 point 989 p1, err := decodePointG1(input[t0:t1]) 990 if err != nil { 991 return nil, err 992 } 993 // Decode G2 point 994 p2, err := decodePointG2(input[t1:t2]) 995 if err != nil { 996 return nil, err 997 } 998 999 // 'point is on curve' check already done, 1000 // Here we need to apply subgroup checks. 1001 if !p1.IsInSubGroup() { 1002 return nil, errBLS12381G1PointSubgroup 1003 } 1004 if !p2.IsInSubGroup() { 1005 return nil, errBLS12381G2PointSubgroup 1006 } 1007 p = append(p, *p1) 1008 q = append(q, *p2) 1009 } 1010 // Prepare 32 byte output 1011 out := make([]byte, 32) 1012 1013 // Compute pairing and set the result 1014 ok, err := bls12381.PairingCheck(p, q) 1015 if err == nil && ok { 1016 out[31] = 1 1017 } 1018 return out, nil 1019 } 1020 1021 func decodePointG1(in []byte) (*bls12381.G1Affine, error) { 1022 if len(in) != 128 { 1023 return nil, errors.New("invalid g1 point length") 1024 } 1025 // decode x 1026 x, err := decodeBLS12381FieldElement(in[:64]) 1027 if err != nil { 1028 return nil, err 1029 } 1030 // decode y 1031 y, err := decodeBLS12381FieldElement(in[64:]) 1032 if err != nil { 1033 return nil, err 1034 } 1035 elem := bls12381.G1Affine{X: x, Y: y} 1036 if !elem.IsOnCurve() { 1037 return nil, errors.New("invalid point: not on curve") 1038 } 1039 1040 return &elem, nil 1041 } 1042 1043 // decodePointG2 given encoded (x, y) coordinates in 256 bytes returns a valid G2 Point. 1044 func decodePointG2(in []byte) (*bls12381.G2Affine, error) { 1045 if len(in) != 256 { 1046 return nil, errors.New("invalid g2 point length") 1047 } 1048 x0, err := decodeBLS12381FieldElement(in[:64]) 1049 if err != nil { 1050 return nil, err 1051 } 1052 x1, err := decodeBLS12381FieldElement(in[64:128]) 1053 if err != nil { 1054 return nil, err 1055 } 1056 y0, err := decodeBLS12381FieldElement(in[128:192]) 1057 if err != nil { 1058 return nil, err 1059 } 1060 y1, err := decodeBLS12381FieldElement(in[192:]) 1061 if err != nil { 1062 return nil, err 1063 } 1064 1065 p := bls12381.G2Affine{X: bls12381.E2{A0: x0, A1: x1}, Y: bls12381.E2{A0: y0, A1: y1}} 1066 if !p.IsOnCurve() { 1067 return nil, errors.New("invalid point: not on curve") 1068 } 1069 return &p, err 1070 } 1071 1072 // decodeBLS12381FieldElement decodes BLS12-381 elliptic curve field element. 1073 // Removes top 16 bytes of 64 byte input. 1074 func decodeBLS12381FieldElement(in []byte) (fp.Element, error) { 1075 if len(in) != 64 { 1076 return fp.Element{}, errors.New("invalid field element length") 1077 } 1078 // check top bytes 1079 for i := 0; i < 16; i++ { 1080 if in[i] != byte(0x00) { 1081 return fp.Element{}, errBLS12381InvalidFieldElementTopBytes 1082 } 1083 } 1084 var res [48]byte 1085 copy(res[:], in[16:]) 1086 1087 return fp.BigEndian.Element(&res) 1088 } 1089 1090 // encodePointG1 encodes a point into 128 bytes. 1091 func encodePointG1(p *bls12381.G1Affine) []byte { 1092 out := make([]byte, 128) 1093 fp.BigEndian.PutElement((*[fp.Bytes]byte)(out[16:]), p.X) 1094 fp.BigEndian.PutElement((*[fp.Bytes]byte)(out[64+16:]), p.Y) 1095 return out 1096 } 1097 1098 // encodePointG2 encodes a point into 256 bytes. 1099 func encodePointG2(p *bls12381.G2Affine) []byte { 1100 out := make([]byte, 256) 1101 // encode x 1102 fp.BigEndian.PutElement((*[fp.Bytes]byte)(out[16:16+48]), p.X.A0) 1103 fp.BigEndian.PutElement((*[fp.Bytes]byte)(out[80:80+48]), p.X.A1) 1104 // encode y 1105 fp.BigEndian.PutElement((*[fp.Bytes]byte)(out[144:144+48]), p.Y.A0) 1106 fp.BigEndian.PutElement((*[fp.Bytes]byte)(out[208:208+48]), p.Y.A1) 1107 return out 1108 } 1109 1110 // bls12381MapG1 implements EIP-2537 MapG1 precompile. 1111 type bls12381MapG1 struct{} 1112 1113 // RequiredGas returns the gas required to execute the pre-compiled contract. 1114 func (c *bls12381MapG1) RequiredGas(input []byte) uint64 { 1115 return params.Bls12381MapG1Gas 1116 } 1117 1118 func (c *bls12381MapG1) Run(input []byte) ([]byte, error) { 1119 // Implements EIP-2537 Map_To_G1 precompile. 1120 // > Field-to-curve call expects an `64` bytes input that is interpreted as an element of the base field. 1121 // > Output of this call is `128` bytes and is G1 point following respective encoding rules. 1122 if len(input) != 64 { 1123 return nil, errBLS12381InvalidInputLength 1124 } 1125 1126 // Decode input field element 1127 fe, err := decodeBLS12381FieldElement(input) 1128 if err != nil { 1129 return nil, err 1130 } 1131 1132 // Compute mapping 1133 r := bls12381.MapToG1(fe) 1134 1135 // Encode the G1 point to 128 bytes 1136 return encodePointG1(&r), nil 1137 } 1138 1139 // bls12381MapG2 implements EIP-2537 MapG2 precompile. 1140 type bls12381MapG2 struct{} 1141 1142 // RequiredGas returns the gas required to execute the pre-compiled contract. 1143 func (c *bls12381MapG2) RequiredGas(input []byte) uint64 { 1144 return params.Bls12381MapG2Gas 1145 } 1146 1147 func (c *bls12381MapG2) Run(input []byte) ([]byte, error) { 1148 // Implements EIP-2537 Map_FP2_TO_G2 precompile logic. 1149 // > Field-to-curve call expects an `128` bytes input that is interpreted as an element of the quadratic extension field. 1150 // > Output of this call is `256` bytes and is G2 point following respective encoding rules. 1151 if len(input) != 128 { 1152 return nil, errBLS12381InvalidInputLength 1153 } 1154 1155 // Decode input field element 1156 c0, err := decodeBLS12381FieldElement(input[:64]) 1157 if err != nil { 1158 return nil, err 1159 } 1160 c1, err := decodeBLS12381FieldElement(input[64:]) 1161 if err != nil { 1162 return nil, err 1163 } 1164 1165 // Compute mapping 1166 r := bls12381.MapToG2(bls12381.E2{A0: c0, A1: c1}) 1167 1168 // Encode the G2 point to 256 bytes 1169 return encodePointG2(&r), nil 1170 } 1171 1172 // kzgPointEvaluation implements the EIP-4844 point evaluation precompile. 1173 type kzgPointEvaluation struct{} 1174 1175 // RequiredGas estimates the gas required for running the point evaluation precompile. 1176 func (b *kzgPointEvaluation) RequiredGas(input []byte) uint64 { 1177 return params.BlobTxPointEvaluationPrecompileGas 1178 } 1179 1180 const ( 1181 blobVerifyInputLength = 192 // Max input length for the point evaluation precompile. 1182 blobCommitmentVersionKZG uint8 = 0x01 // Version byte for the point evaluation precompile. 1183 blobPrecompileReturnValue = "000000000000000000000000000000000000000000000000000000000000100073eda753299d7d483339d80809a1d80553bda402fffe5bfeffffffff00000001" 1184 ) 1185 1186 var ( 1187 errBlobVerifyInvalidInputLength = errors.New("invalid input length") 1188 errBlobVerifyMismatchedVersion = errors.New("mismatched versioned hash") 1189 errBlobVerifyKZGProof = errors.New("error verifying kzg proof") 1190 ) 1191 1192 // Run executes the point evaluation precompile. 1193 func (b *kzgPointEvaluation) Run(input []byte) ([]byte, error) { 1194 if len(input) != blobVerifyInputLength { 1195 return nil, errBlobVerifyInvalidInputLength 1196 } 1197 // versioned hash: first 32 bytes 1198 var versionedHash common.Hash 1199 copy(versionedHash[:], input[:]) 1200 1201 var ( 1202 point kzg4844.Point 1203 claim kzg4844.Claim 1204 ) 1205 // Evaluation point: next 32 bytes 1206 copy(point[:], input[32:]) 1207 // Expected output: next 32 bytes 1208 copy(claim[:], input[64:]) 1209 1210 // input kzg point: next 48 bytes 1211 var commitment kzg4844.Commitment 1212 copy(commitment[:], input[96:]) 1213 if kZGToVersionedHash(commitment) != versionedHash { 1214 return nil, errBlobVerifyMismatchedVersion 1215 } 1216 1217 // Proof: next 48 bytes 1218 var proof kzg4844.Proof 1219 copy(proof[:], input[144:]) 1220 1221 if err := kzg4844.VerifyProof(commitment, point, claim, proof); err != nil { 1222 return nil, fmt.Errorf("%w: %v", errBlobVerifyKZGProof, err) 1223 } 1224 1225 return common.Hex2Bytes(blobPrecompileReturnValue), nil 1226 } 1227 1228 // kZGToVersionedHash implements kzg_to_versioned_hash from EIP-4844 1229 func kZGToVersionedHash(kzg kzg4844.Commitment) common.Hash { 1230 h := sha256.Sum256(kzg[:]) 1231 h[0] = blobCommitmentVersionKZG 1232 1233 return h 1234 }