Use safe_eval instead of eval for issue1640

product.py

@@ -6,6 +6,7 @@ from trytond.model import ModelView, ModelSQL, fields
 from trytond.wizard import Wizard
 from trytond.pyson import PYSONEncoder
 from trytond.transaction import Transaction
+from trytond.tools import safe_eval
 
 
 class Template(ModelSQL, ModelView):
@@ -103,7 +104,7 @@ class Product(ModelSQL, ModelView):
             return False
         if operator == "=":
             operator= "=="
-        return (eval(str(value) + operator + str(operand)))
+        return (safe_eval(str(value) + operator + str(operand)))
 
     def search_quantity(self, name, domain=None):
         date_obj = self.pool.get('ir.date')