Hi, I'm working on a new sandbox project. The goal is to create an empty namespace and write strict rules for the interaction with the existing namespace (full featured Python namespace). By default, you cannot read a file, use print, import a module or exit Python. But you can enable some functions by using config "features". Example: "regex" feature allows you to import the re module which will contain a subset of the real re module, just enough to match a regex. To protect the sandbox namespace, some attributes are "hidden": function closure and globals, frame locals and type subclasses. __builtins__ is also replaced by a read-only dictionary. Objects are not directly injected in the sandbox namespace: a proxy is used to get a read-only view of the object. pysandbox is based on safelite.py, project written by tav one year ago (search tav in python-dev archive, February 2009). I tested RestrictedPython, but the approach is different (rewrite bytecode) and the project is not maintained since 3 or 4 years (only minor updates on the documentation or the copyright header). pysandbox is different than RestrictedPython because it blocks everything by default and has simply config options to enable a set of features. pysandbox is different than safelite.py because it contains unit tests (ensure that blocked features are really blocked). Only attributes/functions allowing to escape the sandbox are blocked. Eg. frames are still accessibles, only the frame locals are blocked. This blacklist policy is broken by design, but it's a nice way to quickly get a working sandbox without having to modify CPython too much. pysandbox status is closer to a proof-of-concept than a beta version, there are open issues (see above). Please test it and try to break it! -- To try pysandbox, download the last version using git clone or a tarball at: http://github.com/haypo/pysandbox/ You don't need to install it, use "python interpreter.py" or "python execfile.py yourscript.py". Use --help to get more options. I tested pysandbox on Linux with Python 2.5, 2.6 and 2.7. I guess that it should work on Python 3.0 with minor changes. -- The current syntax is: config = SandboxConfig(...) with Sandbox(config): ... execute untrusted code here ... This syntax has a problem: local frame variables are not protected by a proxy, nor removed from the sandbox namespace. I tried to remove the frame locals, but Python uses STORE_FAST/LOAD_FAST bytecodes in a function, and this fast cache is not accessible in Python. Clear this cache may introduce unexpected behaviours. pysandbox modify some structure attributes (frame.f_builtins and frame.f_tstate.interp.builtins) directly in memory using some ctypes tricks. I used that to avoid patching CPython and to get faster a working proof-of-concept. Set USE_CPYTHON_HACK to False (in sandbox/__init__.py) to disable these hacks, but they are needed to protect __builtins__ (see related tests). -- By default, pysandbox doesn't use CPython restricted mode, because this mode is too restrictive (it's not possible to read a file or import a module). But pysandbox can use it with SandboxConfig(cpython_restricted=True). -- See README file for more information and TODO file for a longer status. Victor