core/vm: Fix all fixable tests

Non-passing tests still need to be discussed in
https://github.com/ewasm/hera/issues/457 and
https://github.com/ewasm/hera/issues/456

core/vm/evm.go

@@ -420,6 +420,7 @@ func (evm *EVM) create(caller ContractRef, codeAndHash *codeAndHash, gas uint64,
 		for _, interpreter := range evm.interpreters {
 			if interpreter.CanRun(contract.Code) {
 				ret, err = interpreter.PostContractCreation(ret)
+				break
 			}
 		}
 	}

core/vm/ewasm.go

@@ -21,7 +21,6 @@ package vm
 
 import (
 	"bytes"
-	"encoding/binary"
 	"errors"
 	"fmt"
 
@@ -114,52 +113,43 @@ func (in *InterpreterEWASM) Run(contract *Contract, input []byte, ro bool) ([]by
 
 	module, err := wasm.ReadModule(bytes.NewReader(contract.Code), WrappedModuleResolver(in))
 	if err != nil {
+		in.terminationType = TerminateInvalid
 		return nil, fmt.Errorf("Error decoding module at address %s: %v", contract.Address().Hex(), err)
 	}
 
-	// The module should not have any start function
-	if module.Start != nil {
-		return nil, fmt.Errorf("A contract should not have a start function: found #%d", module.Start.Index)
-	}
-
 	vm, err := exec.NewVM(module)
 	if err != nil {
+		in.terminationType = TerminateInvalid
 		return nil, fmt.Errorf("could not create the vm: %v", err)
 	}
 	vm.RecoverPanic = true
 	in.vm = vm
 
-	// Look for the "main" function and execute it after checking it
-	// has the right kind of signature.
-	for name, entry := range module.Export.Entries {
-		if name == "main" && entry.Kind == wasm.ExternalFunction {
+	mainIndex, err := validateModule(module)
+	if err != nil {
+		in.terminationType = TerminateInvalid
+		return nil, err
+	}
+
 
 	// Check input and output types
-			sig := module.FunctionIndexSpace[entry.Index].Sig
+	sig := module.FunctionIndexSpace[mainIndex].Sig
 	if len(sig.ParamTypes) == 0 && len(sig.ReturnTypes) == 0 {
-				_, err = vm.ExecCode(int64(entry.Index))
+		_, err = vm.ExecCode(int64(mainIndex))
 
-				if err != nil {
+		if err != nil && err != errExecutionReverted {
 			in.terminationType = TerminateInvalid
 		}
 
 		if in.StateDB.HasSuicided(contract.Address()) {
-					if initialGas-contract.Gas-params.TxGas < 2*params.SuicideRefundGas {
-						in.StateDB.AddRefund((initialGas - contract.Gas - params.TxGas) / 2)
-					} else {
 			in.StateDB.AddRefund(params.SuicideRefundGas)
-					}
 			err = nil
 		}
 
 		return in.returnData, err
 	}
 
-			// Found a main but it doesn't have the right signature - fail
-			break
-		}
-	}
-
+	in.terminationType = TerminateInvalid
 	return nil, errors.New("Could not find a suitable 'main' function in that contract")
 }
 
@@ -167,15 +157,11 @@ func (in *InterpreterEWASM) Run(contract *Contract, input []byte, ro bool) ([]by
 // if it matches.
 func (in *InterpreterEWASM) CanRun(file []byte) bool {
 	// Check the header
-	if len(file) <= 8 || string(file[:4]) != "\000asm" {
+	if len(file) < 4 || string(file[:4]) != "\000asm" {
 		return false
 	}
 
-	// Check the version
-	ver := binary.LittleEndian.Uint32(file[4:])
-	if ver != 1 {
-		return false
-	}
+
 
 	return true
 }
@@ -200,15 +186,88 @@ func (in *InterpreterEWASM) PreContractCreation(code []byte, contract *Contract)
 	return code, nil
 }
 
+func validateModule(m *wasm.Module) (int, error) {
+	// A module should not have a start section
+	if m.Start != nil {
+		return -1, fmt.Errorf("Module has a start section")
+	}
+
+	// Only two exports are authorized: "main" and "memory"
+	if m.Export == nil {
+		return -1, fmt.Errorf("Module has no exports instead of 2")
+	}
+	if len(m.Export.Entries) != 2 {
+		return -1, fmt.Errorf("Module has %d exports instead of 2", len(m.Export.Entries))
+	}
+
+	mainIndex := -1
+	for name, entry := range m.Export.Entries {
+		switch name {
+		case "main":
+			if entry.Kind != wasm.ExternalFunction {
+				return -1, fmt.Errorf("Main is not a function in module")
+			}
+			mainIndex = int(entry.Index)
+			break
+		case "memory":
+			if entry.Kind != wasm.ExternalMemory {
+				return -1, fmt.Errorf("'memory' is not a memory in module")
+			}
+			break
+		default:
+			return -1, fmt.Errorf("A symbol named %s has been exported. Only main and memory should exist", name)
+		}
+	}
+
+	if m.Import != nil {
+	OUTER:
+		for _, entry := range m.Import.Entries {
+			if entry.ModuleName == "ethereum" {
+				if entry.Type.Kind() == wasm.ExternalFunction {
+					for _, name := range eeiFunctionList {
+						if name == entry.FieldName {
+							continue OUTER
+						}
+					}
+					return -1, fmt.Errorf("%s could not be found in the list of ethereum-provided functions", entry.FieldName)
+				}
+			}
+		}
+	}
+
+	return mainIndex, nil
+}
+
 // PostContractCreation meters the contract once its init code has
-// been run.
+// been run. It also validates the module's format before it is to
+// be committed to disk.
 func (in *InterpreterEWASM) PostContractCreation(code []byte) ([]byte, error) {
+	if in.CanRun(code) {
 		if in.metering {
-		metered, _, err := sentinel(in, code)
-		if len(metered) < 5 || err != nil {
+			code, _, err := sentinel(in, code)
+			if len(code) < 5 || err != nil {
 				return nil, fmt.Errorf("Error metering the generated contract code, err=%v", err)
 			}
-		return metered, nil
+
+			if len(code) < 8 {
+				return nil, fmt.Errorf("Invalid contract code")
 			}
+		}
+
+		if len(code) > 8 {
+			// Check the validity of the module
+			m, err := wasm.DecodeModule(bytes.NewReader(code))
+			if err != nil {
+				return nil, fmt.Errorf("Error decoding the module produced by init code: %v", err)
+			}
+
+			_, err = validateModule(m)
+			if err != nil {
+				in.terminationType = TerminateInvalid
+				return nil, err
+			}
+		}
+	}
+
 	return code, nil
 }

core/vm/ewasm_eei.go

@@ -60,6 +60,7 @@ const (
 	GasCostCall           = 700
 	GasCostCallValue      = 9000
 	GasCostCallStipend    = 2300
+	GasCostNewAccount     = 25000
 	GasCostLog            = 375
 	GasCostLogData        = 8
 	GasCostLogTopic       = 375
@@ -141,7 +142,7 @@ func (in *InterpreterEWASM) gasAccounting(cost uint64) {
 		panic("nil contract")
 	}
 	if cost > in.contract.Gas {
-		panic("out of gas")
+		panic(fmt.Sprintf("out of gas %d > %d", cost, in.contract.Gas))
 	}
 	in.contract.Gas -= cost
 }
@@ -392,7 +393,6 @@ func getBlockHash(p *exec.Process, in *InterpreterEWASM, number int64, resultOff
 
 func callCommon(in *InterpreterEWASM, contract, targetContract *Contract, input []byte, value *big.Int, snapshot int, gas int64, ro bool) int32 {
 	if in.evm.depth > maxCallDepth {
-		contract.UseGas(contract.Gas)
 		return ErrEEICallFailure
 	}
 
@@ -423,8 +423,6 @@ func callCommon(in *InterpreterEWASM, contract, targetContract *Contract, input
 }
 
 func call(p *exec.Process, in *InterpreterEWASM, gas int64, addressOffset int32, valueOffset int32, dataOffset int32, dataLength int32) int32 {
-	in.gasAccounting(GasCostCall)
-
 	contract := in.contract
 
 	// Get the address of the contract to call
@@ -433,11 +431,27 @@ func call(p *exec.Process, in *InterpreterEWASM, gas int64, addressOffset int32,
 	// Get the value. The [spec](https://github.com/ewasm/design/blob/master/eth_interface.md#call)
 	// requires this operation to be U128, which is incompatible with the EVM version that expects
 	// a u256.
-	value := big.NewInt(0).SetBytes(swapEndian(readSize(p, valueOffset, u128Len)))
+	// To be compatible with hera, one must read a u256 value, then check that this is a u128.
+	value := big.NewInt(0).SetBytes(swapEndian(readSize(p, valueOffset, u256Len)))
+	check128bits := big.NewInt(1)
+	check128bits.Lsh(check128bits, 128)
+	if value.Cmp(check128bits) > 0 {
+		return ErrEEICallFailure
+	}
+
+	if in.staticMode == true && value.Cmp(big.NewInt(0)) != 0 {
+		in.gasAccounting(in.contract.Gas)
+		return ErrEEICallFailure
+	}
+
+	in.gasAccounting(GasCostCall)
+
+	if in.evm.depth > maxCallDepth {
+		return ErrEEICallFailure
+	}
 
 	if value.Cmp(big.NewInt(0)) != 0 {
 		in.gasAccounting(GasCostCallValue)
-		gas += GasCostCallStipend
 	}
 
 	// Get the arguments.
@@ -448,31 +462,65 @@ func call(p *exec.Process, in *InterpreterEWASM, gas int64, addressOffset int32,
 
 	snapshot := in.StateDB.Snapshot()
 
-	// Check that the contract exists
-	if !in.StateDB.Exist(addr) {
-		// TODO check that no new account creation stuff is required
-		in.StateDB.CreateAccount(addr)
-	}
-
 	// Check that there is enough balance to transfer the value
 	if in.StateDB.GetBalance(contract.Address()).Cmp(value) < 0 {
-		fmt.Printf("Not enough balance: wanted to use %v, got %v\n", value, in.StateDB.GetBalance(addr))
-		in.contract.Gas += GasCostCallStipend
 		return ErrEEICallFailure
 	}
 
+	// Check that the contract exists
+	if !in.StateDB.Exist(addr) {
+		in.gasAccounting(GasCostNewAccount)
+		in.StateDB.CreateAccount(addr)
+	}
+
+	var calleeGas uint64
+	if uint64(gas) > ((63 * contract.Gas) / 64) {
+		calleeGas = contract.Gas - (contract.Gas / 64)
+	} else {
+		calleeGas = uint64(gas)
+	}
+	in.gasAccounting(calleeGas)
+
+	if value.Cmp(big.NewInt(0)) != 0 {
+		calleeGas += GasCostCallStipend
+	}
+
 	// TODO tracing
-	// TODO check that EIP-150 is respected
 
 	// Add amount to recipient
 	in.evm.Transfer(in.StateDB, contract.Address(), addr, value)
 
 	// Load the contract code in a new VM structure
-	targetContract := NewContract(contract, AccountRef(addr), value, uint64(gas))
+	targetContract := NewContract(contract, AccountRef(addr), value, calleeGas)
 	code := in.StateDB.GetCode(addr)
+	if len(code) == 0 {
+		in.contract.Gas += calleeGas
+		return EEICallSuccess
+	}
 	targetContract.SetCallCode(&addr, in.StateDB.GetCodeHash(addr), code)
 
-	return callCommon(in, contract, targetContract, input, value, snapshot, gas, false)
+	savedVM := in.vm
+
+	in.Run(targetContract, input, false)
+
+	in.vm = savedVM
+	in.contract = contract
+
+	// Add leftover gas
+	in.contract.Gas += targetContract.Gas
+	defer func() { in.terminationType = TerminateFinish }()
+
+	switch in.terminationType {
+	case TerminateFinish:
+		return EEICallSuccess
+	case TerminateRevert:
+		in.StateDB.RevertToSnapshot(snapshot)
+		return ErrEEICallRevert
+	default:
+		in.StateDB.RevertToSnapshot(snapshot)
+		contract.UseGas(targetContract.Gas)
+		return ErrEEICallFailure
+	}
 }
 
 func callDataCopy(p *exec.Process, in *InterpreterEWASM, resultOffset int32, dataOffset int32, length int32) {
@@ -573,8 +621,6 @@ func callDelegate(p *exec.Process, in *InterpreterEWASM, gas int64, addressOffse
 }
 
 func callStatic(p *exec.Process, in *InterpreterEWASM, gas int64, addressOffset int32, dataOffset int32, dataLength int32) int32 {
-	in.gasAccounting(GasCostCall)
-
 	contract := in.contract
 
 	// Get the address of the contract to call
@@ -590,35 +636,62 @@ func callStatic(p *exec.Process, in *InterpreterEWASM, gas int64, addressOffset
 
 	snapshot := in.StateDB.Snapshot()
 
-	// Check that the contract exists
-	if !in.StateDB.Exist(addr) {
-		// TODO check that no new account creation stuff is required
-		in.StateDB.CreateAccount(addr)
-	}
+	in.gasAccounting(GasCostCall)
 
-	// Check that there is enough balance to transfer the value
-	if in.StateDB.GetBalance(addr).Cmp(value) < 0 {
-		fmt.Printf("Not enough balance: wanted to use %v, got %v\n", value, in.StateDB.GetBalance(addr))
-		in.contract.Gas += GasCostCallStipend
+	if in.evm.depth > maxCallDepth {
 		return ErrEEICallFailure
 	}
 
+	// Check that the contract exists
+	if !in.StateDB.Exist(addr) {
+		in.gasAccounting(GasCostNewAccount)
+		in.StateDB.CreateAccount(addr)
+	}
+
+	calleeGas := uint64(gas)
+	if calleeGas > ((63 * contract.Gas) / 64) {
+		calleeGas -= ((63 * contract.Gas) / 64)
+	}
+	in.gasAccounting(calleeGas)
+
 	// TODO tracing
-	// TODO check that EIP-150 is respected
 
 	// Add amount to recipient
 	in.evm.Transfer(in.StateDB, contract.Address(), addr, value)
 
 	// Load the contract code in a new VM structure
-	targetContract := NewContract(contract, AccountRef(addr), value, uint64(gas))
+	targetContract := NewContract(contract, AccountRef(addr), value, calleeGas)
 	code := in.StateDB.GetCode(addr)
+	if len(code) == 0 {
+		in.contract.Gas += calleeGas
+		return EEICallSuccess
+	}
 	targetContract.SetCallCode(&addr, in.StateDB.GetCodeHash(addr), code)
 
+	savedVM := in.vm
 	saveStatic := in.staticMode
 	in.staticMode = true
 	defer func() { in.staticMode = saveStatic }()
 
-	return callCommon(in, contract, targetContract, input, value, snapshot, gas, true)
+	in.Run(targetContract, input, false)
+
+	in.vm = savedVM
+	in.contract = contract
+
+	// Add leftover gas
+	in.contract.Gas += targetContract.Gas
+
+	switch in.terminationType {
+	case TerminateFinish:
+		return EEICallSuccess
+	case TerminateRevert:
+		in.StateDB.RevertToSnapshot(snapshot)
+		return ErrEEICallRevert
+	default:
+		in.StateDB.RevertToSnapshot(snapshot)
+		contract.UseGas(targetContract.Gas)
+		return ErrEEICallFailure
+	}
 }
 
 func storageStore(p *exec.Process, interpreter *InterpreterEWASM, pathOffset int32, valueOffset int32) {
@@ -904,7 +977,6 @@ func selfDestruct(p *exec.Process, in *InterpreterEWASM, addressOffset int32) {
 	balance := in.StateDB.GetBalance(contract.Address())
 
 	addr := common.BytesToAddress(mem[addressOffset : addressOffset+common.AddressLength])
-	in.StateDB.AddBalance(addr, balance)
 
 	totalGas := in.gasTable.Suicide
 	// If the destination address doesn't exist, add the account creation costs
@@ -913,6 +985,7 @@ func selfDestruct(p *exec.Process, in *InterpreterEWASM, addressOffset int32) {
 	}
 	in.gasAccounting(totalGas)
 
+	in.StateDB.AddBalance(addr, balance)
 	in.StateDB.Suicide(contract.Address())
 
 	// Same as for `revert` and `return`, I need to forcefully terminate

tests/state_test_util.go

@@ -161,6 +161,7 @@ func (t *StateTest) Run(subtest StateSubtest, vmconfig vm.Config) (*state.StateD
 	if logs := rlpHash(statedb.Logs()); logs != common.Hash(post.Logs) {
 		return statedb, fmt.Errorf("post state logs hash mismatch: got %x, want %x", logs, post.Logs)
 	}
+
 	return statedb, nil
 }