// Copyright 2020 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 . package vm import ( "errors" "github.com/ethereum/go-ethereum/common" "github.com/ethereum/go-ethereum/common/math" "github.com/ethereum/go-ethereum/params" ) func makeGasSStoreFunc(clearingRefund uint64) gasFunc { return func(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { // If we fail the minimum gas availability invariant, fail (0) if contract.Gas <= params.SstoreSentryGasEIP2200 { return 0, errors.New("not enough gas for reentrancy sentry") } // Gas sentry honoured, do the actual gas calculation based on the stored value var ( y, x = stack.Back(1), stack.peek() slot = common.Hash(x.Bytes32()) current = evm.StateDB.GetState(contract.Address(), slot) cost = uint64(0) ) // Check slot presence in the access list if addrPresent, slotPresent := evm.StateDB.SlotInAccessList(contract.Address(), slot); !slotPresent { cost = params.ColdSloadCostEIP2929 // If the caller cannot afford the cost, this change will be rolled back evm.StateDB.AddSlotToAccessList(contract.Address(), slot) if !addrPresent { // Once we're done with YOLOv2 and schedule this for mainnet, might // be good to remove this panic here, which is just really a // canary to have during testing panic("impossible case: address was not present in access list during sstore op") } } value := common.Hash(y.Bytes32()) if current == value { // noop (1) // EIP 2200 original clause: // return params.SloadGasEIP2200, nil return cost + params.WarmStorageReadCostEIP2929, nil // SLOAD_GAS } original := evm.StateDB.GetCommittedState(contract.Address(), x.Bytes32()) if original == current { if original == (common.Hash{}) { // create slot (2.1.1) return cost + params.SstoreSetGasEIP2200, nil } if value == (common.Hash{}) { // delete slot (2.1.2b) evm.StateDB.AddRefund(clearingRefund) } // EIP-2200 original clause: // return params.SstoreResetGasEIP2200, nil // write existing slot (2.1.2) return cost + (params.SstoreResetGasEIP2200 - params.ColdSloadCostEIP2929), nil // write existing slot (2.1.2) } if original != (common.Hash{}) { if current == (common.Hash{}) { // recreate slot (2.2.1.1) evm.StateDB.SubRefund(clearingRefund) } else if value == (common.Hash{}) { // delete slot (2.2.1.2) evm.StateDB.AddRefund(clearingRefund) } } if original == value { if original == (common.Hash{}) { // reset to original inexistent slot (2.2.2.1) // EIP 2200 Original clause: //evm.StateDB.AddRefund(params.SstoreSetGasEIP2200 - params.SloadGasEIP2200) evm.StateDB.AddRefund(params.SstoreSetGasEIP2200 - params.WarmStorageReadCostEIP2929) } else { // reset to original existing slot (2.2.2.2) // EIP 2200 Original clause: // evm.StateDB.AddRefund(params.SstoreResetGasEIP2200 - params.SloadGasEIP2200) // - SSTORE_RESET_GAS redefined as (5000 - COLD_SLOAD_COST) // - SLOAD_GAS redefined as WARM_STORAGE_READ_COST // Final: (5000 - COLD_SLOAD_COST) - WARM_STORAGE_READ_COST evm.StateDB.AddRefund((params.SstoreResetGasEIP2200 - params.ColdSloadCostEIP2929) - params.WarmStorageReadCostEIP2929) } } // EIP-2200 original clause: //return params.SloadGasEIP2200, nil // dirty update (2.2) return cost + params.WarmStorageReadCostEIP2929, nil // dirty update (2.2) } } // gasSLoadEIP2929 calculates dynamic gas for SLOAD according to EIP-2929 // For SLOAD, if the (address, storage_key) pair (where address is the address of the contract // whose storage is being read) is not yet in accessed_storage_keys, // charge 2100 gas and add the pair to accessed_storage_keys. // If the pair is already in accessed_storage_keys, charge 100 gas. func gasSLoadEIP2929(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { loc := stack.peek() slot := common.Hash(loc.Bytes32()) // Check slot presence in the access list if _, slotPresent := evm.StateDB.SlotInAccessList(contract.Address(), slot); !slotPresent { // If the caller cannot afford the cost, this change will be rolled back // If he does afford it, we can skip checking the same thing later on, during execution evm.StateDB.AddSlotToAccessList(contract.Address(), slot) return params.ColdSloadCostEIP2929, nil } return params.WarmStorageReadCostEIP2929, nil } // gasExtCodeCopyEIP2929 implements extcodecopy according to EIP-2929 // EIP spec: // > If the target is not in accessed_addresses, // > charge COLD_ACCOUNT_ACCESS_COST gas, and add the address to accessed_addresses. // > Otherwise, charge WARM_STORAGE_READ_COST gas. func gasExtCodeCopyEIP2929(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { // memory expansion first (dynamic part of pre-2929 implementation) gas, err := gasExtCodeCopy(evm, contract, stack, mem, memorySize) if err != nil { return 0, err } addr := common.Address(stack.peek().Bytes20()) // Check slot presence in the access list if !evm.StateDB.AddressInAccessList(addr) { evm.StateDB.AddAddressToAccessList(addr) var overflow bool // We charge (cold-warm), since 'warm' is already charged as constantGas if gas, overflow = math.SafeAdd(gas, params.ColdAccountAccessCostEIP2929-params.WarmStorageReadCostEIP2929); overflow { return 0, ErrGasUintOverflow } return gas, nil } return gas, nil } // gasEip2929AccountCheck checks whether the first stack item (as address) is present in the access list. // If it is, this method returns '0', otherwise 'cold-warm' gas, presuming that the opcode using it // is also using 'warm' as constant factor. // This method is used by: // - extcodehash, // - extcodesize, // - (ext) balance func gasEip2929AccountCheck(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { addr := common.Address(stack.peek().Bytes20()) // Check slot presence in the access list if !evm.StateDB.AddressInAccessList(addr) { // If the caller cannot afford the cost, this change will be rolled back evm.StateDB.AddAddressToAccessList(addr) // The warm storage read cost is already charged as constantGas return params.ColdAccountAccessCostEIP2929 - params.WarmStorageReadCostEIP2929, nil } return 0, nil } func makeCallVariantGasCallEIP2929(oldCalculator gasFunc) gasFunc { return func(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { addr := common.Address(stack.Back(1).Bytes20()) // Check slot presence in the access list warmAccess := evm.StateDB.AddressInAccessList(addr) // The WarmStorageReadCostEIP2929 (100) is already deducted in the form of a constant cost, so // the cost to charge for cold access, if any, is Cold - Warm coldCost := params.ColdAccountAccessCostEIP2929 - params.WarmStorageReadCostEIP2929 if !warmAccess { evm.StateDB.AddAddressToAccessList(addr) // Charge the remaining difference here already, to correctly calculate available // gas for call if !contract.UseGas(coldCost) { return 0, ErrOutOfGas } } // Now call the old calculator, which takes into account // - create new account // - transfer value // - memory expansion // - 63/64ths rule gas, err := oldCalculator(evm, contract, stack, mem, memorySize) if warmAccess || err != nil { return gas, err } // In case of a cold access, we temporarily add the cold charge back, and also // add it to the returned gas. By adding it to the return, it will be charged // outside of this function, as part of the dynamic gas, and that will make it // also become correctly reported to tracers. contract.Gas += coldCost return gas + coldCost, nil } } var ( gasCallEIP2929 = makeCallVariantGasCallEIP2929(gasCall) gasDelegateCallEIP2929 = makeCallVariantGasCallEIP2929(gasDelegateCall) gasStaticCallEIP2929 = makeCallVariantGasCallEIP2929(gasStaticCall) gasCallCodeEIP2929 = makeCallVariantGasCallEIP2929(gasCallCode) gasSelfdestructEIP2929 = makeSelfdestructGasFn(true) // gasSelfdestructEIP3529 implements the changes in EIP-2539 (no refunds) gasSelfdestructEIP3529 = makeSelfdestructGasFn(false) // gasSStoreEIP2929 implements gas cost for SSTORE according to EIP-2929 // // When calling SSTORE, check if the (address, storage_key) pair is in accessed_storage_keys. // If it is not, charge an additional COLD_SLOAD_COST gas, and add the pair to accessed_storage_keys. // Additionally, modify the parameters defined in EIP 2200 as follows: // // Parameter Old value New value // SLOAD_GAS 800 = WARM_STORAGE_READ_COST // SSTORE_RESET_GAS 5000 5000 - COLD_SLOAD_COST // //The other parameters defined in EIP 2200 are unchanged. // see gasSStoreEIP2200(...) in core/vm/gas_table.go for more info about how EIP 2200 is specified gasSStoreEIP2929 = makeGasSStoreFunc(params.SstoreClearsScheduleRefundEIP2200) // gasSStoreEIP2539 implements gas cost for SSTORE according to EPI-2539 // Replace `SSTORE_CLEARS_SCHEDULE` with `SSTORE_RESET_GAS + ACCESS_LIST_STORAGE_KEY_COST` (4,800) gasSStoreEIP3529 = makeGasSStoreFunc(params.SstoreClearsScheduleRefundEIP3529) ) // makeSelfdestructGasFn can create the selfdestruct dynamic gas function for EIP-2929 and EIP-2539 func makeSelfdestructGasFn(refundsEnabled bool) gasFunc { gasFunc := func(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) { var ( gas uint64 address = common.Address(stack.peek().Bytes20()) ) if !evm.StateDB.AddressInAccessList(address) { // If the caller cannot afford the cost, this change will be rolled back evm.StateDB.AddAddressToAccessList(address) gas = params.ColdAccountAccessCostEIP2929 } // if empty and transfers value if evm.StateDB.Empty(address) && evm.StateDB.GetBalance(contract.Address()).Sign() != 0 { gas += params.CreateBySelfdestructGas } if refundsEnabled && !evm.StateDB.HasSuicided(contract.Address()) { evm.StateDB.AddRefund(params.SelfdestructRefundGas) } return gas, nil } return gasFunc }