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Issue #14385: Support other types than dict for __builtins__ 

It is now possible to use a custom type for the __builtins__ namespace, instead
of a dict. It can be used for sandboxing for example.  Raise also a NameError
instead of ImportError if __build_class__ name if not found in __builtins__.
This commit is contained in:
Victor Stinner 2012-04-19 00:57:45 +02:00
parent 05fac022ec
commit b0b224233e
4 changed files with 138 additions and 56 deletions
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33
Lib/test/test_builtin.py
View File

@ -554,6 +554,39 @@ class BuiltinTest(unittest.TestCase):
del l['__builtins__']
self.assertEqual((g, l), ({'a': 1}, {'b': 2}))
def test_exec_globals(self):
code = compile("print('Hello World!')", "", "exec")
# no builtin function
self.assertRaisesRegex(NameError, "name 'print' is not defined",
exec, code, {'__builtins__': {}})
# __builtins__ must be a mapping type
self.assertRaises(TypeError,
exec, code, {'__builtins__': 123})
# no __build_class__ function
code = compile("class A: pass", "", "exec")
self.assertRaisesRegex(NameError, "__build_class__ not found",
exec, code, {'__builtins__': {}})
class frozendict_error(Exception):
pass
class frozendict(dict):
def __setitem__(self, key, value):
raise frozendict_error("frozendict is readonly")
# read-only builtins
frozen_builtins = frozendict(__builtins__)
code = compile("__builtins__['superglobal']=2; print(superglobal)", "test", "exec")
self.assertRaises(frozendict_error,
exec, code, {'__builtins__': frozen_builtins})
# read-only globals
namespace = frozendict({})
code = compile("x=1", "test", "exec")
self.assertRaises(frozendict_error,
exec, code, namespace)
def test_exec_redirected(self):
savestdout = sys.stdout
sys.stdout = None # Whatever that cannot flush()

5
Misc/NEWS
View File

@ -10,6 +10,11 @@ What's New in Python 3.3.0 Alpha 3?
Core and Builtins
-----------------
- Issue #14385: It is now possible to use a custom type for the __builtins__
namespace, instead of a dict. It can be used for sandboxing for example.
Raise also a NameError instead of ImportError if __build_class__ name if not
found in __builtins__.
- Issue #12599: Be more strict in accepting None compared to a false-like
object for importlib.util.module_for_loader and
importlib.machinery.PathFinder.

6
Objects/frameobject.c
View File

@ -614,10 +614,8 @@ PyFrame_New(PyThreadState *tstate, PyCodeObject *code, PyObject *globals,
if (builtins) {
if (PyModule_Check(builtins)) {
builtins = PyModule_GetDict(builtins);
assert(!builtins || PyDict_Check(builtins));
assert(builtins != NULL);
}
else if (!PyDict_Check(builtins))
builtins = NULL;
}
if (builtins == NULL) {
/* No builtins! Make up a minimal one
@ -636,7 +634,7 @@ PyFrame_New(PyThreadState *tstate, PyCodeObject *code, PyObject *globals,
/* If we share the globals, we share the builtins.
Save a lookup and a call. */
builtins = back->f_builtins;
assert(builtins != NULL && PyDict_Check(builtins));
assert(builtins != NULL);
Py_INCREF(builtins);
}
if (code->co_zombieframe != NULL) {

48
Python/ceval.c
View File

@ -1932,12 +1932,27 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
TARGET(LOAD_BUILD_CLASS)
{
_Py_IDENTIFIER(__build_class__);
if (PyDict_CheckExact(f->f_builtins)) {
x = _PyDict_GetItemId(f->f_builtins, &PyId___build_class__);
if (x == NULL) {
PyErr_SetString(PyExc_ImportError,
PyErr_SetString(PyExc_NameError,
"__build_class__ not found");
break;
}
}
else {
PyObject *build_class_str = _PyUnicode_FromId(&PyId___build_class__);
if (build_class_str == NULL)
break;
x = PyObject_GetItem(f->f_builtins, build_class_str);
if (x == NULL) {
if (PyErr_ExceptionMatches(PyExc_KeyError))
PyErr_SetString(PyExc_NameError,
"__build_class__ not found");
break;
}
}
Py_INCREF(x);
PUSH(x);
break;
@ -2078,6 +2093,7 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
if (x == NULL) {
x = PyDict_GetItem(f->f_globals, w);
if (x == NULL) {
if (PyDict_CheckExact(f->f_builtins)) {
x = PyDict_GetItem(f->f_builtins, w);
if (x == NULL) {
format_exc_check_arg(
@ -2086,6 +2102,17 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
break;
}
}
else {
x = PyObject_GetItem(f->f_builtins, w);
if (x == NULL) {
if (PyErr_ExceptionMatches(PyExc_KeyError))
format_exc_check_arg(
PyExc_NameError,
NAME_ERROR_MSG, w);
break;
}
}
}
Py_INCREF(x);
}
PUSH(x);
@ -2093,6 +2120,8 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
TARGET(LOAD_GLOBAL)
w = GETITEM(names, oparg);
if (PyDict_CheckExact(f->f_globals)
&& PyDict_CheckExact(f->f_builtins)) {
if (PyUnicode_CheckExact(w)) {
/* Inline the PyDict_GetItem() calls.
WARNING: this is an extreme speed hack.
@ -2143,6 +2172,23 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
Py_INCREF(x);
PUSH(x);
DISPATCH();
}
/* Slow-path if globals or builtins is not a dict */
x = PyObject_GetItem(f->f_globals, w);
if (x == NULL) {
x = PyObject_GetItem(f->f_builtins, w);
if (x == NULL) {
if (PyErr_ExceptionMatches(PyExc_KeyError))
format_exc_check_arg(
PyExc_NameError,
GLOBAL_NAME_ERROR_MSG, w);
break;
}
}
Py_INCREF(x);
PUSH(x);
DISPATCH();
TARGET(DELETE_FAST)
x = GETLOCAL(oparg);