import ../vm_types, interpreter/[gas_meter, gas_costs, utils/utils_numeric, vm_forks], ../errors, stint, eth/[keys, common], chronicles, tables, macros, math, nimcrypto, bncurve/[fields, groups], blake2b_f, ./blscurve type PrecompileAddresses* = enum # Frontier to Spurious Dragron paEcRecover = 1 paSha256 paRipeMd160 paIdentity # Byzantium and Constantinople paModExp paEcAdd paEcMul paPairing # Istanbul paBlake2bf # Berlin paBlsG1Add paBlsG1Mul paBlsG1MultiExp paBlsG2Add paBlsG2Mul paBlsG2MultiExp paBlsPairing paBlsMapG1 paBlsMapG2 iterator activePrecompiles*(): EthAddress = var res: EthAddress for c in PrecompileAddresses.low..PrecompileAddresses.high: res[^1] = c.byte yield res proc getSignature(computation: Computation): (array[32, byte], Signature) = # input is Hash, V, R, S template data: untyped = computation.msg.data var bytes: array[65, byte] # will hold R[32], S[32], V[1], in that order let maxPos = min(data.high, 127) # if we don't have at minimum 64 bytes, there can be no valid V if maxPos >= 63: let v = data[63] # check if V[32] is 27 or 28 if not (v.int in 27..28): raise newException(ValidationError, "Invalid V in getSignature") for x in 32..<63: if data[x] != 0: raise newException(ValidationError, "Invalid V in getSignature") bytes[64] = v - 27 # if there is more data for R and S, copy it. Else, defaulted zeroes are # used for R and S if maxPos >= 64: # Copy message data to buffer bytes[0..(maxPos-64)] = data[64..maxPos] let sig = Signature.fromRaw(bytes) if sig.isErr: raise newException(ValidationError, "Could not recover signature computation") result[1] = sig[] # extract message hash, only need to copy when there is a valid signature result[0][0..31] = data[0..31] else: raise newException(ValidationError, "Invalid V in getSignature") proc simpleDecode*(dst: var FQ2, src: openarray[byte]): bool {.noinit.} = # bypassing FQ2.fromBytes # because we want to check `value > modulus` result = false if dst.c1.fromBytes(src.toOpenArray(0, 31)) and dst.c0.fromBytes(src.toOpenArray(32, 63)): result = true template simpleDecode*(dst: var FQ, src: openarray[byte]): bool = fromBytes(dst, src) proc getPoint[T: G1|G2](t: typedesc[T], data: openarray[byte]): Point[T] = when T is G1: const nextOffset = 32 var px, py: FQ else: const nextOffset = 64 var px, py: FQ2 if not px.simpleDecode(data.toOpenArray(0, nextOffset - 1)): raise newException(ValidationError, "Could not get point value") if not py.simpleDecode(data.toOpenArray(nextOffset, nextOffset * 2 - 1)): raise newException(ValidationError, "Could not get point value") if px.isZero() and py.isZero(): result = T.zero() else: var ap: AffinePoint[T] if not ap.init(px, py): raise newException(ValidationError, "Point is not on curve") result = ap.toJacobian() proc getFR(data: openarray[byte]): FR = if not result.fromBytes2(data): raise newException(ValidationError, "Could not get FR value") proc ecRecover*(computation: Computation) = computation.gasMeter.consumeGas( GasECRecover, reason="ECRecover Precompile") var (msgHash, sig) = computation.getSignature() var pubkey = recover(sig, SkMessage(msgHash)) if pubkey.isErr: raise newException(ValidationError, "Could not derive public key from computation") computation.output.setLen(32) computation.output[12..31] = pubkey[].toCanonicalAddress() trace "ECRecover precompile", derivedKey = pubkey[].toCanonicalAddress() proc sha256*(computation: Computation) = let wordCount = wordCount(computation.msg.data.len) gasFee = GasSHA256 + wordCount * GasSHA256Word computation.gasMeter.consumeGas(gasFee, reason="SHA256 Precompile") computation.output = @(nimcrypto.sha_256.digest(computation.msg.data).data) trace "SHA256 precompile", output = computation.output.toHex proc ripemd160*(computation: Computation) = let wordCount = wordCount(computation.msg.data.len) gasFee = GasRIPEMD160 + wordCount * GasRIPEMD160Word computation.gasMeter.consumeGas(gasFee, reason="RIPEMD160 Precompile") computation.output.setLen(32) computation.output[12..31] = @(nimcrypto.ripemd160.digest(computation.msg.data).data) trace "RIPEMD160 precompile", output = computation.output.toHex proc identity*(computation: Computation) = let wordCount = wordCount(computation.msg.data.len) gasFee = GasIdentity + wordCount * GasIdentityWord computation.gasMeter.consumeGas(gasFee, reason="Identity Precompile") computation.output = computation.msg.data trace "Identity precompile", output = computation.output.toHex proc modExpInternal(computation: Computation, baseLen, expLen, modLen: int, T: type StUint) = template data: untyped {.dirty.} = computation.msg.data let base = data.rangeToPadded[:T](96, 95 + baseLen, baseLen) exp = data.rangeToPadded[:T](96 + baseLen, 95 + baseLen + expLen, expLen) modulo = data.rangeToPadded[:T](96 + baseLen + expLen, 95 + baseLen + expLen + modLen, modLen) # TODO: specs mentions that we should return in "M" format # i.e. if Base and exp are uint512 and Modulo an uint256 # we should return a 256-bit big-endian byte array # Force static evaluation func zero(): array[T.bits div 8, byte] {.compileTime.} = discard func one(): array[T.bits div 8, byte] {.compileTime.} = when cpuEndian == bigEndian: result[0] = 1 else: result[^1] = 1 # Start with EVM special cases let output = if modulo <= 1: # If m == 0: EVM returns 0. # If m == 1: we can shortcut that to 0 as well zero() elif exp.isZero(): # If 0^0: EVM returns 1 # For all x != 0, x^0 == 1 as well one() else: powmod(base, exp, modulo).toByteArrayBE # maximum output len is the same as modLen # if it less than modLen, it will be zero padded at left if output.len >= modLen: computation.output = @(output[^modLen..^1]) else: computation.output = newSeq[byte](modLen) computation.output[^output.len..^1] = output[0..^1] proc modExpFee(c: Computation, baseLen, expLen, modLen: Uint256, fork: Fork): GasInt = template data: untyped {.dirty.} = c.msg.data func mulComplexity(x: Uint256): Uint256 = ## Estimates the difficulty of Karatsuba multiplication if x <= 64.u256: x * x elif x <= 1024.u256: x * x div 4.u256 + 96.u256 * x - 3072.u256 else: x * x div 16.u256 + 480.u256 * x - 199680.u256 func mulComplexityEIP2565(x: Uint256): Uint256 = # gas = ceil(x div 8) ^ 2 result = x + 7 result = result div 8 result = result * result let adjExpLen = block: let baseL = baseLen.safeInt expL = expLen.safeInt first32 = if baseL.uint64 + expL.uint64 < high(int32).uint64 and baseL < data.len: data.rangeToPadded2[:Uint256](96 + baseL, 95 + baseL + expL, min(expL, 32)) else: 0.u256 if expLen <= 32: if first32.isZero(): 0.u256 else: first32.log2.u256 # highest-bit in exponent else: if not first32.isZero: 8.u256 * (expLen - 32.u256) + first32.log2.u256 else: 8.u256 * (expLen - 32.u256) template gasCalc(comp, divisor: untyped): untyped = ( max(modLen, baseLen).comp * max(adjExpLen, 1.u256) ) div divisor # EIP2565: temporary disabled #let gasFee = if fork >= FkBerlin: gasCalc(mulComplexityEIP2565, GasQuadDivisorEIP2565) #else: gasCalc(mulComplexity, GasQuadDivisor) let gasFee = gasCalc(mulComplexity, GasQuadDivisor) if gasFee > high(GasInt).u256: raise newException(OutOfGas, "modExp gas overflow") result = gasFee.truncate(GasInt) # EIP2565: temporary disabled #if fork >= FkBerlin and result < 200.GasInt: # result = 200.GasInt proc modExp*(c: Computation, fork: Fork = FkByzantium) = ## Modular exponentiation precompiled contract ## Yellow Paper Appendix E ## EIP-198 - https://github.com/ethereum/EIPs/blob/master/EIPS/eip-198.md # Parsing the data template data: untyped {.dirty.} = c.msg.data let # lengths Base, Exponent, Modulus baseL = data.rangeToPadded[:Uint256](0, 31) expL = data.rangeToPadded[:Uint256](32, 63) modL = data.rangeToPadded[:Uint256](64, 95) baseLen = baseL.safeInt expLen = expL.safeInt modLen = modL.safeInt let gasFee = modExpFee(c, baseL, expL, modL, fork) c.gasMeter.consumeGas(gasFee, reason="ModExp Precompile") if baseLen == 0 and modLen == 0: # This is a special case where expLength can be very big. c.output = @[] return let maxBytes = max(baseLen, max(expLen, modLen)) if maxBytes <= 32: c.modExpInternal(baseLen, expLen, modLen, UInt256) elif maxBytes <= 64: c.modExpInternal(baseLen, expLen, modLen, StUint[512]) elif maxBytes <= 128: c.modExpInternal(baseLen, expLen, modLen, StUint[1024]) elif maxBytes <= 256: c.modExpInternal(baseLen, expLen, modLen, StUint[2048]) elif maxBytes <= 512: c.modExpInternal(baseLen, expLen, modLen, StUint[4096]) elif maxBytes <= 1024: c.modExpInternal(baseLen, expLen, modLen, StUint[8192]) else: raise newException(EVMError, "The Nimbus VM doesn't support modular exponentiation with numbers larger than uint8192") proc bn256ecAdd*(computation: Computation, fork: Fork = FkByzantium) = let gasFee = if fork < FkIstanbul: GasECAdd else: GasECAddIstanbul computation.gasMeter.consumeGas(gasFee, reason = "ecAdd Precompile") var input: array[128, byte] output: array[64, byte] # Padding data let len = min(computation.msg.data.len, 128) - 1 input[0..len] = computation.msg.data[0..len] var p1 = G1.getPoint(input.toOpenArray(0, 63)) var p2 = G1.getPoint(input.toOpenArray(64, 127)) var apo = (p1 + p2).toAffine() if isSome(apo): # we can discard here because we supply proper buffer discard apo.get().toBytes(output) computation.output = @output proc bn256ecMul*(computation: Computation, fork: Fork = FkByzantium) = let gasFee = if fork < FkIstanbul: GasECMul else: GasECMulIstanbul computation.gasMeter.consumeGas(gasFee, reason="ecMul Precompile") var input: array[96, byte] output: array[64, byte] # Padding data let len = min(computation.msg.data.len, 96) - 1 input[0..len] = computation.msg.data[0..len] var p1 = G1.getPoint(input.toOpenArray(0, 63)) var fr = getFR(input.toOpenArray(64, 95)) var apo = (p1 * fr).toAffine() if isSome(apo): # we can discard here because we supply buffer of proper size discard apo.get().toBytes(output) computation.output = @output proc bn256ecPairing*(computation: Computation, fork: Fork = FkByzantium) = let msglen = len(computation.msg.data) if msglen mod 192 != 0: raise newException(ValidationError, "Invalid input length") let numPoints = msglen div 192 let gasFee = if fork < FkIstanbul: GasECPairingBase + numPoints * GasECPairingPerPoint else: GasECPairingBaseIstanbul + numPoints * GasECPairingPerPointIstanbul computation.gasMeter.consumeGas(gasFee, reason="ecPairing Precompile") var output: array[32, byte] if msglen == 0: # we can discard here because we supply buffer of proper size discard BNU256.one().toBytes(output) else: # Calculate number of pairing pairs let count = msglen div 192 # Pairing accumulator var acc = FQ12.one() for i in 0..= FKByzantium and precompile > paIdentity: computation.error = Error(info: e.msg, burnsGas: true) else: # swallow any other precompiles errors debug "execPrecompiles validation error", msg=e.msg