Limit input count in transaction (iotaledger#1143)

Co-authored-by: Hans Moog <[email protected]>

packages/ledgerstate/input.go

@@ -20,6 +20,12 @@ import (
 const (
 	// UTXOInputType is the type of an Input that references an UTXO Output.
 	UTXOInputType InputType = iota
+
+	// MinInputCount defines the minimum amount of Inputs in a Transaction.
+	MinInputCount = 1
+
+	// MaxInputCount defines the maximum amount of Inputs in a Transaction.
+	MaxInputCount = 127
 )
 
 // InputType represents the type of an Input.
@@ -161,6 +167,14 @@ func InputsFromMarshalUtil(marshalUtil *marshalutil.MarshalUtil) (inputs Inputs,
 		err = xerrors.Errorf("failed to parse inputs count (%v): %w", err, cerrors.ErrParseBytesFailed)
 		return
 	}
+	if inputsCount < MinInputCount {
+		err = xerrors.Errorf("amount of Inputs (%d) failed to reach MinInputCount (%d): %w", inputsCount, MinInputCount, cerrors.ErrParseBytesFailed)
+		return
+	}
+	if inputsCount > MaxInputCount {
+		err = xerrors.Errorf("amount of Inputs (%d) exceeds MaxInputCount (%d): %w", inputsCount, MaxInputCount, cerrors.ErrParseBytesFailed)
+		return
+	}
 
 	var previousInput Input
 	parsedInputs := make([]Input, inputsCount)