ac0ff04460
This PR fixes an overflow which can could happen if inconsistent blockchain rules were configured. Additionally, it tries to prevent such inconsistencies from occurring by making sure that merge cannot be enabled unless previous fork(s) are also enabled.
250 lines
11 KiB
Go
250 lines
11 KiB
Go
// Copyright 2020 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package vm
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import (
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"errors"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/common/math"
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"github.com/ethereum/go-ethereum/params"
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)
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func makeGasSStoreFunc(clearingRefund uint64) gasFunc {
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return func(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
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// If we fail the minimum gas availability invariant, fail (0)
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if contract.Gas <= params.SstoreSentryGasEIP2200 {
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return 0, errors.New("not enough gas for reentrancy sentry")
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}
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// Gas sentry honoured, do the actual gas calculation based on the stored value
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var (
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y, x = stack.Back(1), stack.peek()
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slot = common.Hash(x.Bytes32())
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current = evm.StateDB.GetState(contract.Address(), slot)
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cost = uint64(0)
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)
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// Check slot presence in the access list
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if addrPresent, slotPresent := evm.StateDB.SlotInAccessList(contract.Address(), slot); !slotPresent {
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cost = params.ColdSloadCostEIP2929
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// If the caller cannot afford the cost, this change will be rolled back
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evm.StateDB.AddSlotToAccessList(contract.Address(), slot)
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if !addrPresent {
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// Once we're done with YOLOv2 and schedule this for mainnet, might
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// be good to remove this panic here, which is just really a
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// canary to have during testing
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panic("impossible case: address was not present in access list during sstore op")
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}
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}
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value := common.Hash(y.Bytes32())
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if current == value { // noop (1)
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// EIP 2200 original clause:
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// return params.SloadGasEIP2200, nil
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return cost + params.WarmStorageReadCostEIP2929, nil // SLOAD_GAS
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}
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original := evm.StateDB.GetCommittedState(contract.Address(), x.Bytes32())
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if original == current {
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if original == (common.Hash{}) { // create slot (2.1.1)
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return cost + params.SstoreSetGasEIP2200, nil
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}
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if value == (common.Hash{}) { // delete slot (2.1.2b)
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evm.StateDB.AddRefund(clearingRefund)
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}
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// EIP-2200 original clause:
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// return params.SstoreResetGasEIP2200, nil // write existing slot (2.1.2)
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return cost + (params.SstoreResetGasEIP2200 - params.ColdSloadCostEIP2929), nil // write existing slot (2.1.2)
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}
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if original != (common.Hash{}) {
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if current == (common.Hash{}) { // recreate slot (2.2.1.1)
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evm.StateDB.SubRefund(clearingRefund)
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} else if value == (common.Hash{}) { // delete slot (2.2.1.2)
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evm.StateDB.AddRefund(clearingRefund)
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}
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}
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if original == value {
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if original == (common.Hash{}) { // reset to original inexistent slot (2.2.2.1)
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// EIP 2200 Original clause:
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//evm.StateDB.AddRefund(params.SstoreSetGasEIP2200 - params.SloadGasEIP2200)
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evm.StateDB.AddRefund(params.SstoreSetGasEIP2200 - params.WarmStorageReadCostEIP2929)
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} else { // reset to original existing slot (2.2.2.2)
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// EIP 2200 Original clause:
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// evm.StateDB.AddRefund(params.SstoreResetGasEIP2200 - params.SloadGasEIP2200)
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// - SSTORE_RESET_GAS redefined as (5000 - COLD_SLOAD_COST)
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// - SLOAD_GAS redefined as WARM_STORAGE_READ_COST
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// Final: (5000 - COLD_SLOAD_COST) - WARM_STORAGE_READ_COST
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evm.StateDB.AddRefund((params.SstoreResetGasEIP2200 - params.ColdSloadCostEIP2929) - params.WarmStorageReadCostEIP2929)
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}
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}
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// EIP-2200 original clause:
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//return params.SloadGasEIP2200, nil // dirty update (2.2)
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return cost + params.WarmStorageReadCostEIP2929, nil // dirty update (2.2)
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}
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}
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// gasSLoadEIP2929 calculates dynamic gas for SLOAD according to EIP-2929
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// For SLOAD, if the (address, storage_key) pair (where address is the address of the contract
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// whose storage is being read) is not yet in accessed_storage_keys,
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// charge 2100 gas and add the pair to accessed_storage_keys.
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// If the pair is already in accessed_storage_keys, charge 100 gas.
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func gasSLoadEIP2929(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
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loc := stack.peek()
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slot := common.Hash(loc.Bytes32())
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// Check slot presence in the access list
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if _, slotPresent := evm.StateDB.SlotInAccessList(contract.Address(), slot); !slotPresent {
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// If the caller cannot afford the cost, this change will be rolled back
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// If he does afford it, we can skip checking the same thing later on, during execution
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evm.StateDB.AddSlotToAccessList(contract.Address(), slot)
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return params.ColdSloadCostEIP2929, nil
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}
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return params.WarmStorageReadCostEIP2929, nil
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}
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// gasExtCodeCopyEIP2929 implements extcodecopy according to EIP-2929
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// EIP spec:
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// > If the target is not in accessed_addresses,
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// > charge COLD_ACCOUNT_ACCESS_COST gas, and add the address to accessed_addresses.
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// > Otherwise, charge WARM_STORAGE_READ_COST gas.
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func gasExtCodeCopyEIP2929(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
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// memory expansion first (dynamic part of pre-2929 implementation)
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gas, err := gasExtCodeCopy(evm, contract, stack, mem, memorySize)
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if err != nil {
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return 0, err
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}
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addr := common.Address(stack.peek().Bytes20())
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// Check slot presence in the access list
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if !evm.StateDB.AddressInAccessList(addr) {
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evm.StateDB.AddAddressToAccessList(addr)
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var overflow bool
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// We charge (cold-warm), since 'warm' is already charged as constantGas
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if gas, overflow = math.SafeAdd(gas, params.ColdAccountAccessCostEIP2929-params.WarmStorageReadCostEIP2929); overflow {
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return 0, ErrGasUintOverflow
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}
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return gas, nil
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}
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return gas, nil
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}
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// gasEip2929AccountCheck checks whether the first stack item (as address) is present in the access list.
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// If it is, this method returns '0', otherwise 'cold-warm' gas, presuming that the opcode using it
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// is also using 'warm' as constant factor.
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// This method is used by:
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// - extcodehash,
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// - extcodesize,
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// - (ext) balance
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func gasEip2929AccountCheck(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
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addr := common.Address(stack.peek().Bytes20())
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// Check slot presence in the access list
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if !evm.StateDB.AddressInAccessList(addr) {
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// If the caller cannot afford the cost, this change will be rolled back
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evm.StateDB.AddAddressToAccessList(addr)
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// The warm storage read cost is already charged as constantGas
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return params.ColdAccountAccessCostEIP2929 - params.WarmStorageReadCostEIP2929, nil
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}
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return 0, nil
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}
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func makeCallVariantGasCallEIP2929(oldCalculator gasFunc) gasFunc {
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return func(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
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addr := common.Address(stack.Back(1).Bytes20())
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// Check slot presence in the access list
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warmAccess := evm.StateDB.AddressInAccessList(addr)
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// The WarmStorageReadCostEIP2929 (100) is already deducted in the form of a constant cost, so
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// the cost to charge for cold access, if any, is Cold - Warm
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coldCost := params.ColdAccountAccessCostEIP2929 - params.WarmStorageReadCostEIP2929
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if !warmAccess {
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evm.StateDB.AddAddressToAccessList(addr)
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// Charge the remaining difference here already, to correctly calculate available
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// gas for call
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if !contract.UseGas(coldCost) {
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return 0, ErrOutOfGas
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}
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}
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// Now call the old calculator, which takes into account
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// - create new account
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// - transfer value
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// - memory expansion
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// - 63/64ths rule
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gas, err := oldCalculator(evm, contract, stack, mem, memorySize)
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if warmAccess || err != nil {
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return gas, err
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}
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// In case of a cold access, we temporarily add the cold charge back, and also
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// add it to the returned gas. By adding it to the return, it will be charged
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// outside of this function, as part of the dynamic gas, and that will make it
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// also become correctly reported to tracers.
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contract.Gas += coldCost
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var overflow bool
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if gas, overflow = math.SafeAdd(gas, coldCost); overflow {
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return 0, ErrGasUintOverflow
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}
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return gas, nil
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}
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}
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var (
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gasCallEIP2929 = makeCallVariantGasCallEIP2929(gasCall)
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gasDelegateCallEIP2929 = makeCallVariantGasCallEIP2929(gasDelegateCall)
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gasStaticCallEIP2929 = makeCallVariantGasCallEIP2929(gasStaticCall)
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gasCallCodeEIP2929 = makeCallVariantGasCallEIP2929(gasCallCode)
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gasSelfdestructEIP2929 = makeSelfdestructGasFn(true)
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// gasSelfdestructEIP3529 implements the changes in EIP-3529 (no refunds)
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gasSelfdestructEIP3529 = makeSelfdestructGasFn(false)
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// gasSStoreEIP2929 implements gas cost for SSTORE according to EIP-2929
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//
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// When calling SSTORE, check if the (address, storage_key) pair is in accessed_storage_keys.
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// If it is not, charge an additional COLD_SLOAD_COST gas, and add the pair to accessed_storage_keys.
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// Additionally, modify the parameters defined in EIP 2200 as follows:
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//
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// Parameter Old value New value
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// SLOAD_GAS 800 = WARM_STORAGE_READ_COST
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// SSTORE_RESET_GAS 5000 5000 - COLD_SLOAD_COST
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//
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//The other parameters defined in EIP 2200 are unchanged.
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// see gasSStoreEIP2200(...) in core/vm/gas_table.go for more info about how EIP 2200 is specified
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gasSStoreEIP2929 = makeGasSStoreFunc(params.SstoreClearsScheduleRefundEIP2200)
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// gasSStoreEIP3529 implements gas cost for SSTORE according to EIP-3529
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// Replace `SSTORE_CLEARS_SCHEDULE` with `SSTORE_RESET_GAS + ACCESS_LIST_STORAGE_KEY_COST` (4,800)
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gasSStoreEIP3529 = makeGasSStoreFunc(params.SstoreClearsScheduleRefundEIP3529)
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)
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// makeSelfdestructGasFn can create the selfdestruct dynamic gas function for EIP-2929 and EIP-3529
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func makeSelfdestructGasFn(refundsEnabled bool) gasFunc {
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gasFunc := func(evm *EVM, contract *Contract, stack *Stack, mem *Memory, memorySize uint64) (uint64, error) {
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var (
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gas uint64
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address = common.Address(stack.peek().Bytes20())
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)
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if !evm.StateDB.AddressInAccessList(address) {
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// If the caller cannot afford the cost, this change will be rolled back
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evm.StateDB.AddAddressToAccessList(address)
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gas = params.ColdAccountAccessCostEIP2929
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}
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// if empty and transfers value
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if evm.StateDB.Empty(address) && evm.StateDB.GetBalance(contract.Address()).Sign() != 0 {
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gas += params.CreateBySelfdestructGas
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}
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if refundsEnabled && !evm.StateDB.HasSelfDestructed(contract.Address()) {
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evm.StateDB.AddRefund(params.SelfdestructRefundGas)
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}
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return gas, nil
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}
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return gasFunc
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}
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