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# -*- coding: utf-8 -*-
# Part of Odoo. See LICENSE file for full copyright and licensing details.
"""
safe_eval module - methods intended to provide more restricted alternatives to
evaluate simple and/or untrusted code.
Methods in this module are typically used as alternatives to eval() to parse
OpenERP domain strings, conditions and expressions, mostly based on locals
condition/math builtins.
"""
# Module partially ripped from/inspired by several different sources:
# - http://code.activestate.com/recipes/286134/
# - safe_eval in lp:~xrg/openobject-server/optimize-5.0
# - safe_eval in tryton http://hg.tryton.org/hgwebdir.cgi/trytond/rev/bbb5f73319ad
import dis
import functools
import logging
import sys
import types
import typing
from opcode import opmap, opname
from types import CodeType
import werkzeug
from psycopg2 import OperationalError
import odoo.exceptions
unsafe_eval = eval
__all__ = ['const_eval', 'safe_eval']
# The time module is usually already provided in the safe_eval environment
# but some code, e.g. datetime.datetime.now() (Windows/Python 2.5.2, bug
# lp:703841), does import time.
_ALLOWED_MODULES = ['_strptime', 'math', 'time']
# Mock __import__ function, as called by cpython's import emulator `PyImport_Import` inside
# timemodule.c, _datetimemodule.c and others.
# This function does not actually need to do anything, its expected side-effect is to make the
# imported module available in `sys.modules`. The _ALLOWED_MODULES are imported below to make it so.
def _import(name, globals=None, locals=None, fromlist=None, level=-1):
if name not in sys.modules:
raise ImportError(f'module {name} should be imported before calling safe_eval()')
for module in _ALLOWED_MODULES:
__import__(module)
_UNSAFE_ATTRIBUTES = [
# Frames
'f_builtins', 'f_code', 'f_globals', 'f_locals',
# Python 2 functions
'func_code', 'func_globals',
# Code object
'co_code', '_co_code_adaptive',
# Method resolution order,
'mro',
# Tracebacks
'tb_frame',
# Generators
'gi_code', 'gi_frame', 'gi_yieldfrom',
# Coroutines
'cr_await', 'cr_code', 'cr_frame',
# Coroutine generators
'ag_await', 'ag_code', 'ag_frame',
]
def to_opcodes(opnames, _opmap=opmap):
for x in opnames:
if x in _opmap:
yield _opmap[x]
# opcodes which absolutely positively must not be usable in safe_eval,
# explicitly subtracted from all sets of valid opcodes just in case
_BLACKLIST = set(to_opcodes([
# can't provide access to accessing arbitrary modules
'IMPORT_STAR', 'IMPORT_NAME', 'IMPORT_FROM',
# could allow replacing or updating core attributes on models & al, setitem
# can be used to set field values
'STORE_ATTR', 'DELETE_ATTR',
# no reason to allow this
'STORE_GLOBAL', 'DELETE_GLOBAL',
]))
# opcodes necessary to build literal values
_CONST_OPCODES = set(to_opcodes([
# stack manipulations
'POP_TOP', 'ROT_TWO', 'ROT_THREE', 'ROT_FOUR', 'DUP_TOP', 'DUP_TOP_TWO',
'LOAD_CONST',
'RETURN_VALUE', # return the result of the literal/expr evaluation
# literal collections
'BUILD_LIST', 'BUILD_MAP', 'BUILD_TUPLE', 'BUILD_SET',
# 3.6: literal map with constant keys https://bugs.python.org/issue27140
'BUILD_CONST_KEY_MAP',
'LIST_EXTEND', 'SET_UPDATE',
# 3.11 replace DUP_TOP, DUP_TOP_TWO, ROT_TWO, ROT_THREE, ROT_FOUR
'COPY', 'SWAP',
# Added in 3.11 https://docs.python.org/3/whatsnew/3.11.html#new-opcodes
'RESUME',
# 3.12 https://docs.python.org/3/whatsnew/3.12.html#cpython-bytecode-changes
'RETURN_CONST',
# 3.13
'TO_BOOL',
])) - _BLACKLIST
# operations which are both binary and inplace, same order as in doc'
_operations = [
'POWER', 'MULTIPLY', # 'MATRIX_MULTIPLY', # matrix operator (3.5+)
'FLOOR_DIVIDE', 'TRUE_DIVIDE', 'MODULO', 'ADD',
'SUBTRACT', 'LSHIFT', 'RSHIFT', 'AND', 'XOR', 'OR',
]
# operations on literal values
_EXPR_OPCODES = _CONST_OPCODES.union(to_opcodes([
'UNARY_POSITIVE', 'UNARY_NEGATIVE', 'UNARY_NOT', 'UNARY_INVERT',
*('BINARY_' + op for op in _operations), 'BINARY_SUBSCR',
*('INPLACE_' + op for op in _operations),
'BUILD_SLICE',
# comprehensions
'LIST_APPEND', 'MAP_ADD', 'SET_ADD',
'COMPARE_OP',
# specialised comparisons
'IS_OP', 'CONTAINS_OP',
'DICT_MERGE', 'DICT_UPDATE',
# Basically used in any "generator literal"
'GEN_START', # added in 3.10 but already removed from 3.11.
# Added in 3.11, replacing all BINARY_* and INPLACE_*
'BINARY_OP',
'BINARY_SLICE',
])) - _BLACKLIST
_SAFE_OPCODES = _EXPR_OPCODES.union(to_opcodes([
'POP_BLOCK', 'POP_EXCEPT',
# note: removed in 3.8
'SETUP_LOOP', 'SETUP_EXCEPT', 'BREAK_LOOP', 'CONTINUE_LOOP',
'EXTENDED_ARG', # P3.6 for long jump offsets.
'MAKE_FUNCTION', 'CALL_FUNCTION', 'CALL_FUNCTION_KW', 'CALL_FUNCTION_EX',
# Added in P3.7 https://bugs.python.org/issue26110
'CALL_METHOD', 'LOAD_METHOD',
'GET_ITER', 'FOR_ITER', 'YIELD_VALUE',
'JUMP_FORWARD', 'JUMP_ABSOLUTE', 'JUMP_BACKWARD',
'JUMP_IF_FALSE_OR_POP', 'JUMP_IF_TRUE_OR_POP', 'POP_JUMP_IF_FALSE', 'POP_JUMP_IF_TRUE',
'SETUP_FINALLY', 'END_FINALLY',
# Added in 3.8 https://bugs.python.org/issue17611
'BEGIN_FINALLY', 'CALL_FINALLY', 'POP_FINALLY',
'RAISE_VARARGS', 'LOAD_NAME', 'STORE_NAME', 'DELETE_NAME', 'LOAD_ATTR',
'LOAD_FAST', 'STORE_FAST', 'DELETE_FAST', 'UNPACK_SEQUENCE',
'STORE_SUBSCR',
'LOAD_GLOBAL',
'RERAISE', 'JUMP_IF_NOT_EXC_MATCH',
# Following opcodes were Added in 3.11
# replacement of opcodes CALL_FUNCTION, CALL_FUNCTION_KW, CALL_METHOD
'PUSH_NULL', 'PRECALL', 'CALL', 'KW_NAMES',
# replacement of POP_JUMP_IF_TRUE and POP_JUMP_IF_FALSE
'POP_JUMP_FORWARD_IF_FALSE', 'POP_JUMP_FORWARD_IF_TRUE',
'POP_JUMP_BACKWARD_IF_FALSE', 'POP_JUMP_BACKWARD_IF_TRUE',
# special case of the previous for IS NONE / IS NOT NONE
'POP_JUMP_FORWARD_IF_NONE', 'POP_JUMP_BACKWARD_IF_NONE',
'POP_JUMP_FORWARD_IF_NOT_NONE', 'POP_JUMP_BACKWARD_IF_NOT_NONE',
# replacement of JUMP_IF_NOT_EXC_MATCH
'CHECK_EXC_MATCH',
# new opcodes
'RETURN_GENERATOR',
'PUSH_EXC_INFO',
'NOP',
'FORMAT_VALUE', 'BUILD_STRING',
# 3.12 https://docs.python.org/3/whatsnew/3.12.html#cpython-bytecode-changes
'END_FOR',
'LOAD_FAST_AND_CLEAR', 'LOAD_FAST_CHECK',
'POP_JUMP_IF_NOT_NONE', 'POP_JUMP_IF_NONE',
'CALL_INTRINSIC_1',
'STORE_SLICE',
# 3.13
'CALL_KW', 'LOAD_FAST_LOAD_FAST',
'STORE_FAST_STORE_FAST', 'STORE_FAST_LOAD_FAST',
'CONVERT_VALUE', 'FORMAT_SIMPLE', 'FORMAT_WITH_SPEC',
'SET_FUNCTION_ATTRIBUTE',
])) - _BLACKLIST
_logger = logging.getLogger(__name__)
def assert_no_dunder_name(code_obj, expr):
""" assert_no_dunder_name(code_obj, expr) -> None
Asserts that the code object does not refer to any "dunder name"
(__$name__), so that safe_eval prevents access to any internal-ish Python
attribute or method (both are loaded via LOAD_ATTR which uses a name, not a
const or a var).
Checks that no such name exists in the provided code object (co_names).
:param code_obj: code object to name-validate
:type code_obj: CodeType
:param str expr: expression corresponding to the code object, for debugging
purposes
:raises NameError: in case a forbidden name (containing two underscores)
is found in ``code_obj``
.. note:: actually forbids every name containing 2 underscores
"""
for name in code_obj.co_names:
if "__" in name or name in _UNSAFE_ATTRIBUTES:
raise NameError('Access to forbidden name %r (%r)' % (name, expr))
def assert_valid_codeobj(allowed_codes, code_obj, expr):
""" Asserts that the provided code object validates against the bytecode
and name constraints.
Recursively validates the code objects stored in its co_consts in case
lambdas are being created/used (lambdas generate their own separated code
objects and don't live in the root one)
:param allowed_codes: list of permissible bytecode instructions
:type allowed_codes: set(int)
:param code_obj: code object to name-validate
:type code_obj: CodeType
:param str expr: expression corresponding to the code object, for debugging
purposes
:raises ValueError: in case of forbidden bytecode in ``code_obj``
:raises NameError: in case a forbidden name (containing two underscores)
is found in ``code_obj``
"""
assert_no_dunder_name(code_obj, expr)
# set operations are almost twice as fast as a manual iteration + condition
# when loading /web according to line_profiler
code_codes = {i.opcode for i in dis.get_instructions(code_obj)}
if not allowed_codes >= code_codes:
raise ValueError("forbidden opcode(s) in %r: %s" % (expr, ', '.join(opname[x] for x in (code_codes - allowed_codes))))
for const in code_obj.co_consts:
if isinstance(const, CodeType):
assert_valid_codeobj(allowed_codes, const, 'lambda')
def compile_codeobj(expr: str, /, filename: str = '<unknown>', mode: typing.Literal['eval', 'exec'] = 'eval'):
"""
:param str filename: optional pseudo-filename for the compiled expression,
displayed for example in traceback frames
:param str mode: 'eval' if single expression
'exec' if sequence of statements
:return: compiled code object
:rtype: types.CodeType
"""
assert mode in ('eval', 'exec')
try:
if mode == 'eval':
expr = expr.strip() # eval() does not like leading/trailing whitespace
code_obj = compile(expr, filename or '', mode)
except (SyntaxError, TypeError, ValueError):
raise
except Exception as e:
raise ValueError('%r while compiling\n%r' % (e, expr))
return code_obj
def const_eval(expr):
"""const_eval(expression) -> value
Safe Python constant evaluation
Evaluates a string that contains an expression describing
a Python constant. Strings that are not valid Python expressions
or that contain other code besides the constant raise ValueError.
>>> const_eval("10")
10
>>> const_eval("[1,2, (3,4), {'foo':'bar'}]")
[1, 2, (3, 4), {'foo': 'bar'}]
>>> const_eval("1+2")
Traceback (most recent call last):
...
ValueError: opcode BINARY_ADD not allowed
"""
c = compile_codeobj(expr)
assert_valid_codeobj(_CONST_OPCODES, c, expr)
return unsafe_eval(c)
def expr_eval(expr):
"""expr_eval(expression) -> value
Restricted Python expression evaluation
Evaluates a string that contains an expression that only
uses Python constants. This can be used to e.g. evaluate
a numerical expression from an untrusted source.
>>> expr_eval("1+2")
3
>>> expr_eval("[1,2]*2")
[1, 2, 1, 2]
>>> expr_eval("__import__('sys').modules")
Traceback (most recent call last):
...
ValueError: opcode LOAD_NAME not allowed
"""
c = compile_codeobj(expr)
assert_valid_codeobj(_EXPR_OPCODES, c, expr)
return unsafe_eval(c)
_BUILTINS = {
'__import__': _import,
'True': True,
'False': False,
'None': None,
'bytes': bytes,
'str': str,
'unicode': str,
'bool': bool,
'int': int,
'float': float,
'enumerate': enumerate,
'dict': dict,
'list': list,
'tuple': tuple,
'map': map,
'abs': abs,
'min': min,
'max': max,
'sum': sum,
'reduce': functools.reduce,
'filter': filter,
'sorted': sorted,
'round': round,
'len': len,
'repr': repr,
'set': set,
'all': all,
'any': any,
'ord': ord,
'chr': chr,
'divmod': divmod,
'isinstance': isinstance,
'range': range,
'xrange': range,
'zip': zip,
'Exception': Exception,
}
_BUBBLEUP_EXCEPTIONS = (
odoo.exceptions.UserError,
odoo.exceptions.RedirectWarning,
werkzeug.exceptions.HTTPException,
OperationalError, # let auto-replay of serialized transactions work its magic
ZeroDivisionError,
)
def safe_eval(expr, /, context=None, *, mode="eval", filename=None):
"""System-restricted Python expression evaluation
Evaluates a string that contains an expression that mostly
uses Python constants, arithmetic expressions and the
objects directly provided in context.
This can be used to e.g. evaluate
a domain expression from an untrusted source.
:param expr: The Python expression (or block, if ``mode='exec'``) to evaluate.
:type expr: string | bytes
:param context: Namespace available to the expression.
This dict will be mutated with any variables created during
evaluation
:type context: dict
:param mode: ``exec`` or ``eval``
:type mode: str
:param filename: optional pseudo-filename for the compiled expression,
displayed for example in traceback frames
:type filename: string
:throws TypeError: If the expression provided is a code object
:throws SyntaxError: If the expression provided is not valid Python
:throws NameError: If the expression provided accesses forbidden names
:throws ValueError: If the expression provided uses forbidden bytecode
"""
if type(expr) is CodeType:
raise TypeError("safe_eval does not allow direct evaluation of code objects.")
assert context is None or type(context) is dict, "Context must be a dict"
check_values(context)
globals_dict = dict(context or {}, __builtins__=dict(_BUILTINS))
c = compile_codeobj(expr, filename=filename, mode=mode)
assert_valid_codeobj(_SAFE_OPCODES, c, expr)
try:
# empty locals dict makes the eval behave like top-level code
return unsafe_eval(c, globals_dict, None)
except _BUBBLEUP_EXCEPTIONS:
raise
except Exception as e:
raise ValueError('%r while evaluating\n%r' % (e, expr))
finally:
if context is not None:
del globals_dict['__builtins__']
context.update(globals_dict)
def test_python_expr(expr, mode="eval"):
try:
c = compile_codeobj(expr, mode=mode)
assert_valid_codeobj(_SAFE_OPCODES, c, expr)
except (SyntaxError, TypeError, ValueError) as err:
if len(err.args) >= 2 and len(err.args[1]) >= 4:
error = {
'message': err.args[0],
'filename': err.args[1][0],
'lineno': err.args[1][1],
'offset': err.args[1][2],
'error_line': err.args[1][3],
}
msg = "%s : %s at line %d\n%s" % (type(err).__name__, error['message'], error['lineno'], error['error_line'])
else:
msg = str(err)
return msg
return False
def check_values(d):
if not d:
return d
for v in d.values():
if isinstance(v, types.ModuleType):
raise TypeError(f"""Module {v} can not be used in evaluation contexts
Prefer providing only the items necessary for your intended use.
If a "module" is necessary for backwards compatibility, use
`odoo.tools.safe_eval.wrap_module` to generate a wrapper recursively
whitelisting allowed attributes.
Pre-wrapped modules are provided as attributes of `odoo.tools.safe_eval`.
""")
return d
class wrap_module:
def __init__(self, module, attributes):
"""Helper for wrapping a package/module to expose selected attributes
:param module: the actual package/module to wrap, as returned by ``import <module>``
:param iterable attributes: attributes to expose / whitelist. If a dict,
the keys are the attributes and the values
are used as an ``attributes`` in case the
corresponding item is a submodule
"""
# builtin modules don't have a __file__ at all
modfile = getattr(module, '__file__', '(built-in)')
self._repr = f"<wrapped {module.__name__!r} ({modfile})>"
for attrib in attributes:
target = getattr(module, attrib)
if isinstance(target, types.ModuleType):
target = wrap_module(target, attributes[attrib])
setattr(self, attrib, target)
def __repr__(self):
return self._repr
# dateutil submodules are lazy so need to import them for them to "exist"
import dateutil
mods = ['parser', 'relativedelta', 'rrule', 'tz']
for mod in mods:
__import__('dateutil.%s' % mod)
# make sure to patch pytz before exposing
from odoo._monkeypatches.pytz import patch_module as patch_pytz # noqa: E402, F401
patch_pytz()
datetime = wrap_module(__import__('datetime'), ['date', 'datetime', 'time', 'timedelta', 'timezone', 'tzinfo', 'MAXYEAR', 'MINYEAR'])
dateutil = wrap_module(dateutil, {
"tz": ["UTC", "tzutc"],
"parser": ["isoparse", "parse"],
"relativedelta": ["relativedelta", "MO", "TU", "WE", "TH", "FR", "SA", "SU"],
"rrule": ["rrule", "rruleset", "rrulestr", "YEARLY", "MONTHLY", "WEEKLY", "DAILY", "HOURLY", "MINUTELY", "SECONDLY", "MO", "TU", "WE", "TH", "FR", "SA", "SU"],
})
json = wrap_module(__import__('json'), ['loads', 'dumps'])
time = wrap_module(__import__('time'), ['time', 'strptime', 'strftime', 'sleep'])
pytz = wrap_module(__import__('pytz'), [
'utc', 'UTC', 'timezone',
])
dateutil.tz.gettz = pytz.timezone