RestrictedPython 7.4

RestrictedPython is a defined subset of the Python language which allows to provide a program input into a trusted environment.

RestrictedPython

RestrictedPython is a tool that helps to define a subset of the Python language which allows to provide a program input into a trusted environment. RestrictedPython is not a sandbox system or a secured environment, but it helps to define a trusted environment and execute untrusted code inside of it.

Warning

RestrictedPython only supports CPython. It does _not_ support PyPy and other Python implementations as it cannot provide its restrictions there.

For full documentation please see http://restrictedpython.readthedocs.io/.

Example

To give a basic understanding what RestrictedPython does here two examples:

An unproblematic code example

Python allows you to execute a large set of commands. This would not harm any system.

>>> from RestrictedPython import compile_restricted
>>> from RestrictedPython import safe_globals
>>>
>>> source_code = """
... def example():
...     return 'Hello World!'
... """
>>>
>>> loc = {}
>>> byte_code = compile_restricted(source_code, '<inline>', 'exec')
>>> exec(byte_code, safe_globals, loc)
>>>
>>> loc['example']()
'Hello World!'

Problematic code example

This example directly executed in Python could harm your system.

>>> from RestrictedPython import compile_restricted
>>> from RestrictedPython import safe_globals
>>>
>>> source_code = """
... import os
...
... os.listdir('/')
... """
>>> byte_code = compile_restricted(source_code, '<inline>', 'exec')
>>> exec(byte_code, safe_globals, {})
Traceback (most recent call last):
ImportError: __import__ not found

Contributing to RestrictedPython

If you want to help maintain RestrictedPython and contribute, please refer to the documentation Contributing page.

Changes

7.4 (2024-10-09)

• Allow to use the package with Python 3.13.

• Drop support for Python 3.7.

• Provide new function RestrictedPython.Guards.safer_getattr_raise. It is similar to safer_getattr but handles its parameter default like getattr, i.e. it raises AttributeError if the attribute lookup fails and this parameter is not provided, fixes #287.

7.3 (2024-09-30)

• Increase the safety level of safer_getattr allowing applications to use it as getattr implementation. Such use should now follow the same policy and give the same level of protection as direct attribute access in an environment based on RestrictedPython’s safe_builtints.

• Prevent information leakage via AttributeError.obj and the string module. (CVE-2024-47532)

7.2 (2024-08-02)

• Remove unneeded setuptools fossils that may cause installation problems with recent setuptools versions.

• Add support for single mode statements / execution.

• Fix a potential breakout capability in the provided safer_getattr method that is part of the safer_builtins.

7.1 (2024-03-14)

• Add support for the matmul (@) operator.

7.0 (2023-11-17)

Backwards incompatible changes

• Drop support for Python 3.6.

Features

• Officially support Python 3.12.

Fixes

• Prevent DeprecationWarnings from ast.Str and ast.Num on Python 3.12

• Forbid using some attributes providing access to restricted Python internals. (CVE-2023-37271)

• Fix information disclosure problems through Python’s “format” functionality (format and format_map methods on str and its instances, string.Formatter). (CVE-2023-41039)

6.0 (2022-11-03)

Backwards incompatible changes

• Drop support for Python 2.7 and 3.5.

Features

• Officially support Python 3.11.

• Allow to use the Python 3.11 feature of exception groups and except* (PEP 654).

5.2 (2021-11-19)

• Document that __name__ is needed to define classes.

• Add support for Python 3.10. Auditing the Python 3.10 change log did not reveal any changes which require actions in RestrictedPython.

• Avoid deprecation warnings when using Python 3.8+. (#192)

5.1 (2020-10-07)

Features

• Add support for (Python 3.8+) assignment expressions (i.e. the := operator)

• Add support for Python 3.9 after checking the security implications of the syntax changes made in that version.

• Add support for the bytes and sorted builtins (#186)

Documentation

• Document parameter mode for the compile_restricted functions (#157)

• Fix documentation for compile_restricted_function (#158)

Fixes

• Fix compile_restricted_function with SyntaxErrors that have no text (#181)

• Drop install dependency on setuptools. (#189)

5.0 (2019-09-03)

Breaking changes

• Revert the allowance of the ... (Ellipsis) statement, as of 4.0. It is not needed to support Python 3.8. The security implications of the Ellipsis Statement is not 100 % clear and is not checked. ... (Ellipsis) is disallowed again.

Features

• Add support for f-strings in Python 3.6+. (#123)

4.0 (2019-05-10)

Changes since 3.6.0:

Breaking changes

• The compile_restricted* functions now return a namedtuple CompileResult instead of a simple tuple.

• Drop the old implementation of version 3.x: RCompile.py, SelectCompiler.py, MutatingWorker.py, RestrictionMutator.py and tests/verify.py.

• Drop support for long-deprecated sets module.

Security related issues

• RestrictedPython now ships with a default implementation for _getattr_ which prevents from using the format() method on str/unicode as it is not safe, see: http://lucumr.pocoo.org/2016/12/29/careful-with-str-format/

  Caution: If you do not already have secured the access to this format() method in your _getattr_ implementation use RestrictedPython.Guards.safer_getattr() in your implementation to benefit from this fix.

Features

• Mostly complete rewrite based on Python AST module. [loechel (Alexander Loechel), icemac (Michael Howitz), stephan-hof (Stephan Hofmockel), tlotze (Thomas Lotze)]

• Add support for Python 3.5, 3.6, 3.7.

• Add preliminary support for Python 3.8. as of 3.8.0a3 is released.

• Warn when using another Python implementation than CPython as it is not safe to use RestrictedPython with other versions than CPyton. See https://bitbucket.org/pypy/pypy/issues/2653 for PyPy.

• Allow the ... (Ellipsis) statement. It is needed to support Python 3.8.

• Allow yield and yield from statements. Generator functions would now work in RestrictedPython.

• Allow the following magic methods to be defined on classes. (#104) They cannot be called directly but by the built-in way to use them (e. g. class instantiation, or comparison):

  • __init__

  • __contains__

  • __lt__

  • __le__

  • __eq__

  • __ne__

  • __gt__

  • __ge__

• Imports like from a import * (so called star imports) are now forbidden as they allow to import names starting with an underscore which could override protected build-ins. (#102)

• Allow to use list comprehensions in the default implementation of RestrictionCapableEval.eval().

• Switch to pytest as test runner.

• Bring test coverage to 100 %.

Bug fixes

• Improve .Guards.safer_getattr to prevent accessing names starting with underscore. (#142)

3.6.0 (2010-07-09)

• Add name check for names assigned during imports using the from x import y format.

• Add test for name check when assigning an alias using multiple-context with statements in Python 2.7.

• Add tests for protection of the iterators for dict and set comprehensions in Python 2.7.

3.6.0a1 (2010-06-05)

• Remove support for DocumentTemplate.sequence - this is handled in the DocumentTemplate package itself.

3.5.2 (2010-04-30)

• Remove a testing dependency on zope.testing.

3.5.1 (2009-03-17)

• Add tests for Utilities module.

• Filter DeprecationWarnings when importing Python’s sets module.

3.5.0 (2009-02-09)

• Drop legacy support for Python 2.1 / 2.2 (__future__ imports of nested_scopes / generators.).

3.4.3 (2008-10-26)

• Fix deprecation warning: with is now a reserved keyword on Python 2.6. That means RestrictedPython should run on Python 2.6 now. Thanks to Ranjith Kannikara, GSoC Student for the patch.

• Add tests for ternary if expression and for with keyword and context managers.

3.4.2 (2007-07-28)

• Changed homepage URL to the PyPI site

• Improve README.txt.

3.4.1 (2007-06-23)

• Fix http://www.zope.org/Collectors/Zope/2295: Bare conditional in a Zope 2 PythonScript followed by a comment causes SyntaxError.

3.4.0 (2007-06-04)

• RestrictedPython now has its own release cycle as a separate project.

• Synchronized with RestrictedPython from Zope 2 tree.

3.2.0 (2006-01-05)

• Corresponds to the verison of the RestrictedPython package shipped as part of the Zope 3.2.0 release.

• No changes from 3.1.0.

3.1.0 (2005-10-03)

• Corresponds to the verison of the RestrictedPython package shipped as part of the Zope 3.1.0 release.

• Remove unused fossil module, SafeMapping.

• Replaced use of deprecated whrandom module with random (aliased to whrandom for backward compatibility).

3.0.0 (2004-11-07)

• Corresponds to the verison of the RestrictedPython package shipped as part of the Zope X3.0.0 release.