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params: core, core/vm, miner: 64bit gas instructions (#3514)

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Reworked the EVM gas instructions to use 64bit integers rather than
arbitrary size big ints. All gas operations, be it additions,
multiplications or divisions, are checked and guarded against 64 bit
integer overflows.

In additon, most of the protocol paramaters in the params package have
been converted to uint64 and are now constants rather than variables.

* common/math: added overflow check ops
* core: vmenv, env renamed to evm
* eth, internal/ethapi, les: unmetered eth_call and cancel methods
* core/vm: implemented big.Int pool for evm instructions
* core/vm: unexported intPool methods & verification methods
* core/vm: added memoryGasCost overflow check and test
This commit is contained in:
Jeffrey Wilcke
2017-02-02 15:25:42 +01:00
committed by GitHub
parent 296450451b
commit 8b57c49490
47 changed files with 1043 additions and 784 deletions
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86
core/state_transition.go
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@ -49,15 +49,16 @@ The state transitioning model does all all the necessary work to work out a vali
6) Derive new state root
*/
type StateTransition struct {
gp *GasPool
msg Message
gas, gasPrice *big.Int
initialGas *big.Int
value *big.Int
data []byte
state vm.StateDB
gp *GasPool
msg Message
gas uint64
gasPrice *big.Int
initialGas *big.Int
value *big.Int
data []byte
state vm.StateDB
env *vm.EVM
evm *vm.EVM
}
// Message represents a message sent to a contract.
@ -81,12 +82,14 @@ func MessageCreatesContract(msg Message) bool {
// IntrinsicGas computes the 'intrinsic gas' for a message
// with the given data.
//
// TODO convert to uint64
func IntrinsicGas(data []byte, contractCreation, homestead bool) *big.Int {
igas := new(big.Int)
if contractCreation && homestead {
igas.Set(params.TxGasContractCreation)
igas.SetUint64(params.TxGasContractCreation)
} else {
igas.Set(params.TxGas)
igas.SetUint64(params.TxGas)
}
if len(data) > 0 {
var nz int64
@ -96,27 +99,26 @@ func IntrinsicGas(data []byte, contractCreation, homestead bool) *big.Int {
}
}
m := big.NewInt(nz)
m.Mul(m, params.TxDataNonZeroGas)
m.Mul(m, new(big.Int).SetUint64(params.TxDataNonZeroGas))
igas.Add(igas, m)
m.SetInt64(int64(len(data)) - nz)
m.Mul(m, params.TxDataZeroGas)
m.Mul(m, new(big.Int).SetUint64(params.TxDataZeroGas))
igas.Add(igas, m)
}
return igas
}
// NewStateTransition initialises and returns a new state transition object.
func NewStateTransition(env *vm.EVM, msg Message, gp *GasPool) *StateTransition {
func NewStateTransition(evm *vm.EVM, msg Message, gp *GasPool) *StateTransition {
return &StateTransition{
gp: gp,
env: env,
evm: evm,
msg: msg,
gas: new(big.Int),
gasPrice: msg.GasPrice(),
initialGas: new(big.Int),
value: msg.Value(),
data: msg.Data(),
state: env.StateDB,
state: evm.StateDB,
}
}
@ -127,8 +129,8 @@ func NewStateTransition(env *vm.EVM, msg Message, gp *GasPool) *StateTransition
// the gas used (which includes gas refunds) and an error if it failed. An error always
// indicates a core error meaning that the message would always fail for that particular
// state and would never be accepted within a block.
func ApplyMessage(env *vm.EVM, msg Message, gp *GasPool) ([]byte, *big.Int, error) {
st := NewStateTransition(env, msg, gp)
func ApplyMessage(evm *vm.EVM, msg Message, gp *GasPool) ([]byte, *big.Int, error) {
st := NewStateTransition(evm, msg, gp)
ret, _, gasUsed, err := st.TransitionDb()
return ret, gasUsed, err
@ -157,21 +159,21 @@ func (self *StateTransition) to() vm.Account {
return self.state.GetAccount(*to)
}
func (self *StateTransition) useGas(amount *big.Int) error {
if self.gas.Cmp(amount) < 0 {
func (self *StateTransition) useGas(amount uint64) error {
if self.gas < amount {
return vm.ErrOutOfGas
}
self.gas.Sub(self.gas, amount)
self.gas -= amount
return nil
}
func (self *StateTransition) addGas(amount *big.Int) {
self.gas.Add(self.gas, amount)
}
func (self *StateTransition) buyGas() error {
mgas := self.msg.Gas()
if mgas.BitLen() > 64 {
return vm.ErrOutOfGas
}
mgval := new(big.Int).Mul(mgas, self.gasPrice)
sender := self.from()
@ -181,7 +183,8 @@ func (self *StateTransition) buyGas() error {
if err := self.gp.SubGas(mgas); err != nil {
return err
}
self.addGas(mgas)
self.gas += mgas.Uint64()
self.initialGas.Set(mgas)
sender.SubBalance(mgval)
return nil
@ -209,7 +212,9 @@ func (self *StateTransition) preCheck() (err error) {
return nil
}
// TransitionDb will move the state by applying the message against the given environment.
// TransitionDb will transition the state by applying the current message and returning the result
// including the required gas for the operation as well as the used gas. It returns an error if it
// failed. An error indicates a consensus issue.
func (self *StateTransition) TransitionDb() (ret []byte, requiredGas, usedGas *big.Int, err error) {
if err = self.preCheck(); err != nil {
return
@ -217,26 +222,32 @@ func (self *StateTransition) TransitionDb() (ret []byte, requiredGas, usedGas *b
msg := self.msg
sender := self.from() // err checked in preCheck
homestead := self.env.ChainConfig().IsHomestead(self.env.BlockNumber)
homestead := self.evm.ChainConfig().IsHomestead(self.evm.BlockNumber)
contractCreation := MessageCreatesContract(msg)
// Pay intrinsic gas
if err = self.useGas(IntrinsicGas(self.data, contractCreation, homestead)); err != nil {
// TODO convert to uint64
intrinsicGas := IntrinsicGas(self.data, contractCreation, homestead)
if intrinsicGas.BitLen() > 64 {
return nil, nil, nil, InvalidTxError(vm.ErrOutOfGas)
}
if err = self.useGas(intrinsicGas.Uint64()); err != nil {
return nil, nil, nil, InvalidTxError(err)
}
var (
vmenv = self.env
evm = self.evm
// vm errors do not effect consensus and are therefor
// not assigned to err, except for insufficient balance
// error.
vmerr error
)
if contractCreation {
ret, _, vmerr = vmenv.Create(sender, self.data, self.gas, self.value)
ret, _, self.gas, vmerr = evm.Create(sender, self.data, self.gas, self.value)
} else {
// Increment the nonce for the next transaction
self.state.SetNonce(sender.Address(), self.state.GetNonce(sender.Address())+1)
ret, vmerr = vmenv.Call(sender, self.to().Address(), self.data, self.gas, self.value)
ret, self.gas, vmerr = evm.Call(sender, self.to().Address(), self.data, self.gas, self.value)
}
if vmerr != nil {
glog.V(logger.Core).Infoln("vm returned with error:", err)
@ -251,7 +262,7 @@ func (self *StateTransition) TransitionDb() (ret []byte, requiredGas, usedGas *b
requiredGas = new(big.Int).Set(self.gasUsed())
self.refundGas()
self.state.AddBalance(self.env.Coinbase, new(big.Int).Mul(self.gasUsed(), self.gasPrice))
self.state.AddBalance(self.evm.Coinbase, new(big.Int).Mul(self.gasUsed(), self.gasPrice))
return ret, requiredGas, self.gasUsed(), err
}
@ -260,20 +271,21 @@ func (self *StateTransition) refundGas() {
// Return eth for remaining gas to the sender account,
// exchanged at the original rate.
sender := self.from() // err already checked
remaining := new(big.Int).Mul(self.gas, self.gasPrice)
remaining := new(big.Int).Mul(new(big.Int).SetUint64(self.gas), self.gasPrice)
sender.AddBalance(remaining)
// Apply refund counter, capped to half of the used gas.
uhalf := remaining.Div(self.gasUsed(), common.Big2)
refund := common.BigMin(uhalf, self.state.GetRefund())
self.gas.Add(self.gas, refund)
self.gas += refund.Uint64()
self.state.AddBalance(sender.Address(), refund.Mul(refund, self.gasPrice))
// Also return remaining gas to the block gas counter so it is
// available for the next transaction.
self.gp.AddGas(self.gas)
self.gp.AddGas(new(big.Int).SetUint64(self.gas))
}
func (self *StateTransition) gasUsed() *big.Int {
return new(big.Int).Sub(self.initialGas, self.gas)
return new(big.Int).Sub(self.initialGas, new(big.Int).SetUint64(self.gas))
}