RestrictedPython 5.1

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

Changes

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.