diff --git a/lib/ansible/template/safe_eval.py b/lib/ansible/template/safe_eval.py index ffb48611e27..d82373a6fb9 100644 --- a/lib/ansible/template/safe_eval.py +++ b/lib/ansible/template/safe_eval.py @@ -41,6 +41,14 @@ def safe_eval(expr, locals={}, include_exceptions=False): http://stackoverflow.com/questions/12523516/using-ast-and-whitelists-to-make-pythons-eval-safe ''' + # define certain JSON types + # eg. JSON booleans are unknown to python eval() + JSON_TYPES = { + 'false': False, + 'null': None, + 'true': True, + } + # this is the whitelist of AST nodes we are going to # allow in the evaluation. Any node type other than # those listed here will raise an exception in our custom @@ -116,7 +124,7 @@ def safe_eval(expr, locals={}, include_exceptions=False): parsed_tree = ast.parse(expr, mode='eval') cnv.visit(parsed_tree) compiled = compile(parsed_tree, expr, 'eval') - result = eval(compiled, {}, dict(locals)) + result = eval(compiled, JSON_TYPES, dict(locals)) if include_exceptions: return (result, None)