Metadata-Version: 1.1
Name: boxed
Version: 0.3.2
Summary: Simple and lightweight sandbox solution for Python an Linux.
Home-page: UNKNOWN
Author: Fábio Macêdo Mendes
Author-email: fabiomacedomendes@gmail.com
License: UNKNOWN
Description: Boxed is a simple sandboxing solution for Python. It works by running arbitrary
        Python functions in a separate python interpreter as an unprivileged user.
        
        The API is very simple::
        
            from boxed import run
        
            result = run(target_func, args=args, kwargs=kwargs)
        
        This will spawn a Python interpreted that drops its privileges and runs
        ``target_func(*args, **kwds)`` as the **nobody** user. Communication
        between the master and slave processes is done using serialized streams
        which can use pickle, cloudpickle, dill or JSON.
        
        There is a possible vulnerability if the target function outputs a
        picklable object that produces malicious side-effects when unpickled. We don't
        know how to exploit this vulnerability, but it is theoretically possible, so be
        warned. Dill and cloudpickle are likely to be more vulnerable since both can
        pickle function bytecodes, opening many doors for attack.
        
        The possibility of damage is greatly reduced by using the JSON serializer.
        The downside is that both inputs and outputs must be JSON-compatible (i.e., they
        must be composed of basic types such as numbers, strings, lists and dicts.
        Besides that, the target function itself must be a Python callable living in a
        public namespace: the JSON serializer just sends the function full qualified
        name to the sandbox and import this function there.
        
        ::
        
            >>> from boxed import run
            >>> from math import sqrt
            >>> run(sqrt, args=(4,), serializer='json')
            2.0
        
        
        
        How does it work?
        =================
        
        The sandbox is spawned as a different Python interpreter using the python_boxed
        executable which is created during installation. This is just a copy of the regular
        interpreter with Linux's SETUID capability enabled. This simple technique allows a
        process to change its UID during execution, which enable it to drop its privileges
        early during execution.
        
        This might remember the infamous SUID bit. SUID executables allows an user to spawn
        program that starts its life with super user permissions and (hopefully) drop
        them as soon as possible while keeping only the permissions necessary for it
        to run. The classical example is a webserver. Only the super user can
        listen to port 80 (or any other lower ports), thus the webserver must start its
        life as root and quickly drop all privileges but those necessary to communicate in
        the desired ports.
        
        Linux capabilities is a fine-grained version of the SUID bit. We can grant
        very specific super user privileges to a program. The boxed library uses a Python
        interpreter with the SETUID capability which grant us only the
        permission of changing the UID of a process. Even if the process escalates its
        privileges to run with UID=0 (the super user), none of the other permissions are
        granted so it will not gain any super powers. In particular, it will not be
        able to read, write or execute any file that user who executed the sandbox did
        not have access to.
        
        By default, ``boxed`` runs the sandbox as the `nobody` user. We create a copy of
        the interpreter called /usr/bin/python_boxed during installatin and then apply
        the command::
        
            $ setcap cap_setuid+ep /usr/bin/python_boxed
        
        
        Does it work on Windows, OSX, BSD, etc?
        =======================================
        
        No. This technique is linux-specific. Also, it is very difficult to provide a good,
        lightweight, and cross-platform sandboxing solution. We have no plans to implement
        sandboxing in other platforms.
Platform: any
Classifier: Development Status :: 4 - Beta
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: GNU General Public License (GPL)
Classifier: Operating System :: POSIX :: Linux
Classifier: Programming Language :: Python :: 3 :: Only
Classifier: Topic :: Software Development :: Libraries
