/
validator.go
114 lines (93 loc) · 2.83 KB
/
validator.go
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package contexts
import (
"fmt"
"unicode"
"github.com/ElrondNetwork/arwen-wasm-vm/arwen"
"github.com/ElrondNetwork/arwen-wasm-vm/wasmer"
"github.com/ElrondNetwork/elrond-go/core/vmcommon"
)
const noArity = -1
// wasmValidator is a validator for WASM SmartContracts
type wasmValidator struct {
reserved *reservedFunctions
}
// newWASMValidator creates a new WASMValidator
func newWASMValidator(scAPINames vmcommon.FunctionNames, protocolBuiltinFunctions vmcommon.FunctionNames) *wasmValidator {
return &wasmValidator{
reserved: NewReservedFunctions(scAPINames, protocolBuiltinFunctions),
}
}
func (validator *wasmValidator) verifyMemoryDeclaration(instance wasmer.InstanceHandler) error {
if !instance.HasMemory() {
return arwen.ErrMemoryDeclarationMissing
}
return nil
}
func (validator *wasmValidator) verifyFunctions(instance wasmer.InstanceHandler) error {
for functionName := range instance.GetExports() {
err := validator.verifyValidFunctionName(functionName)
if err != nil {
return err
}
err = validator.verifyVoidFunction(instance, functionName)
if err != nil {
return err
}
}
return nil
}
func (validator *wasmValidator) verifyVoidFunction(instance wasmer.InstanceHandler, functionName string) error {
inArity, err := validator.getInputArity(instance, functionName)
if err != nil {
return err
}
outArity, err := validator.getOutputArity(instance, functionName)
if err != nil {
return err
}
isVoid := inArity == 0 && outArity == 0
if !isVoid {
return fmt.Errorf("%w: %s", arwen.ErrFunctionNonvoidSignature, functionName)
}
return nil
}
func (validator *wasmValidator) getInputArity(instance wasmer.InstanceHandler, functionName string) (int, error) {
signature, ok := instance.GetSignature(functionName)
if !ok {
return noArity, fmt.Errorf("%w: %s", arwen.ErrFuncNotFound, functionName)
}
return signature.InputArity, nil
}
func (validator *wasmValidator) getOutputArity(instance wasmer.InstanceHandler, functionName string) (int, error) {
signature, ok := instance.GetSignature(functionName)
if !ok {
return noArity, fmt.Errorf("%w: %s", arwen.ErrFuncNotFound, functionName)
}
return signature.OutputArity, nil
}
func (validator *wasmValidator) verifyValidFunctionName(functionName string) error {
const maxLengthOfFunctionName = 256
errInvalidName := fmt.Errorf("%w: %s", arwen.ErrInvalidFunctionName, functionName)
if len(functionName) == 0 {
return errInvalidName
}
if len(functionName) >= maxLengthOfFunctionName {
return errInvalidName
}
if !isASCIIString(functionName) {
return errInvalidName
}
if validator.reserved.IsReserved(functionName) {
return errInvalidName
}
return nil
}
// TODO: Add more constraints (too loose currently)
func isASCIIString(input string) bool {
for i := 0; i < len(input); i++ {
if input[i] > unicode.MaxASCII {
return false
}
}
return true
}