Revert "[ADD] tools: patch C types, e.g. str.format"
This reverts commit 66832f0ba0.
This commit is contained in:
Denis Ledoux
@@ -1,8 +1,6 @@
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import ast
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import ctypes
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import os
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import logging
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import string
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from shutil import copyfileobj
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from types import CodeType
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@@ -14,8 +12,6 @@ from werkzeug.wrappers import Request, Response
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from .json import scriptsafe
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from odoo.tools.safe_eval import _UNSAFE_ATTRIBUTES
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try:
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from xlrd import xlsx
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except ImportError:
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@@ -69,140 +65,3 @@ def literal_eval(expr):
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return orig_literal_eval(expr)
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ast.literal_eval = literal_eval
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def _is_safe_expr(expr):
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return '__' not in expr and not any(att_name in expr for att_name in _UNSAFE_ATTRIBUTES)
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origin_formatter_get_field = string.Formatter.get_field
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def get_field(self, field_name, args, kwargs):
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# Monkey-patch `get_field` to raise in case of access to a forbidden name
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# Ref: https://github.com/python/cpython/blob/812245ecce2d8344c3748228047bab456816180a/Lib/string.py#L267
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if not _is_safe_expr(field_name):
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raise NameError('Access to forbidden name %r' % (field_name))
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return origin_formatter_get_field(self, field_name, args, kwargs)
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string.Formatter.get_field = get_field
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#
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# Monkey-Patch C types
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#
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# PyTypeObject is not in Python ABI, so we map it to a custom ctypes Struct
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class PyTypeObject(ctypes.Structure):
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# Ref: https://docs.python.org/3/c-api/typeobj.html
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_fields_ = [
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# cover PyObject variable header https://docs.python.org/3/c-api/typeobj.html#pyobject-slots
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# + 15 first PyTypeObject slots: https://docs.python.org/3/c-api/typeobj.html#pytypeobject-slots
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('_', 18 * ctypes.c_void_p),
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# https://docs.python.org/3/c-api/typeobj.html#c.PyTypeObject.tp_getattro
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('tp_getattro', ctypes.CFUNCTYPE(ctypes.py_object, ctypes.py_object, ctypes.py_object)),
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('_', 14 * ctypes.c_void_p), # cover 14 slots, not needed so far
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# https://docs.python.org/3/c-api/typeobj.html#c.PyTypeObject.tp_dict
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('tp_dict', ctypes.py_object),
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('_', 3 * ctypes.c_void_p), # cover 3 slots, not needed so far
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# https://docs.python.org/3/c-api/typeobj.html#c.PyTypeObject.tp_init
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# /!\ last param mapped to c_void_p because it's nullable and PyObject doesn't support it
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('tp_init', ctypes.CFUNCTYPE(ctypes.c_int, ctypes.py_object, ctypes.py_object, ctypes.c_void_p)),
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]
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_slot_mapping = {
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# python_method: slot_name
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'__init__': 'tp_init',
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}
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def patch_c_type(cls, attr, value):
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# obtain the address of the C type - don't assume id(cls) is guaranteed to hold it
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cls_pt = ctypes.py_object(cls)
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cls_addr = ctypes.POINTER(ctypes.c_void_p)(cls_pt)[0]
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# cast into our custom PyTypeObject struct
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obj = PyTypeObject.from_address(cls_addr)
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# CASE 1. Slot functions: replace slot function pointer
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if attr.startswith("__") and attr.endswith("__"):
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slot_func = PyTypeObject._slot_mapping[attr]
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c_func_type = dict(PyTypeObject._fields_)[slot_func]
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c_func = c_func_type(value) # C callback pointer for our patch function
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# incref: store a ref in the type's __dict__
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cls_dict = getattr(obj, "tp_dict")
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cls_dict.setdefault('__patch_refs__', []).append(c_func)
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# apply patch function
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setattr(obj, slot_func, c_func)
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# CASE 2. Other methods: replace the method in the __dict__ of the type
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else:
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cls_dict = getattr(obj, "tp_dict")
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origin = cls_dict.get(attr)
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if origin:
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value.__name__ = origin.__name__
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value.__qualname__ = origin.__qualname__
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# apply patch function
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cls_dict[attr] = value
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# clear internal caches: https://docs.python.org/3/c-api/type.html#c.PyType_Modified
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ctypes.pythonapi.PyType_Modified(cls_pt)
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# Monkey-patch AttributeError to suppress assignation of `.obj`
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if hasattr(AttributeError, 'obj'):
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# AttributeError.name, AttributeError.obj added in Python 3.10
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# https://github.com/python/cpython/commit/37494b441aced0362d7edd2956ab3ea7801e60c8
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def __init__(self, args, kwargs):
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if kwargs:
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# py_object isn't NULLABLE, so we manually handle the NULL case from a void pointer
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kwargs = ctypes.cast(kwargs, ctypes.py_object).value
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else:
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kwargs = {}
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# emulate super __init__, we don't want to call it, it's cheaper
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# it's here: https://github.com/python/cpython/blob/d0524caed0f3b77f271640460d0dff1a4c784087/Objects/exceptions.c#L1404
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self.name = kwargs.get('name')
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# assign .obj immediately so set_attribute_error_context() won't do it
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# cfr https://github.com/python/cpython/commit/3b3be05a164da43f201e35b6dafbc840993a4d18
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self.obj = None # pretend it was not really assigned (None != NULL pointer)
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return 0
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patch_c_type(AttributeError, "__init__", __init__)
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def _mkpatch_str_format():
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# Monkey-patch str.format to forbid usage of dunder attributes in replacement fields,
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# keeping all refs in the closure
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formatter = string.Formatter() # thread-safe parsing, can be shared
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origin_format = str.format
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origin_format_map = str.format_map
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def _safe_format_fields(s):
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# First quick pass with strstr(), matching both `{0.__foo__}` and `__{0}__`
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if not _is_safe_expr(s):
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# Second pass with a real parsing for "format fields" to avoid blocking `__{0}__`. cfr PEP-3101.
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field_exprs = tuple(field_expr for _lit, field_expr, _fmt, _conv in formatter.parse(s) if field_expr)
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for expr in field_exprs:
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if not _is_safe_expr(expr):
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return False
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return True
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def format(*args, **kwargs):
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if not _safe_format_fields(args[0]):
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return args[0] # pretend we forgot to format
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return origin_format(*args, **kwargs)
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def format_map(*args, **kwargs):
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if not _safe_format_fields(args[0]):
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return args[0] # pretend we forgot to format
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return origin_format_map(*args, **kwargs)
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patch_c_type(str, "format", format)
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patch_c_type(str, "format_map", format_map)
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_mkpatch_str_format()
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