Files
edx-platform/xmodule/capa/safe_exec
Tim McCormack 2009e8972c feat: Set TMPDIR for codejail executions (#36412)
This makes it easier to run matplotlib in codejail, and should prevent a
number of other issues in the future with other packages that need to
create tempfiles.

No change is required for existing codejail installations, but after this
change operators may be able to tighten their apparmor configuration to
prevent write access to global temp or cache dirs.

Manual testing instructions: Create a codejail problem that runs
`import matplotlib` and confirm that it runs without error. (Unit tests
aren't feasible here because this requires a fully configured codejail in
order for the tmp subdirectory to exist.)

Also: Add comment for `OPENBLAS_NUM_THREADS` and numpy support.
2025-03-20 15:41:43 -04:00
..

Configuring Capa sandboxed execution
====================================

Capa problems can contain code authored by the course author.  We need to
execute that code in a sandbox.  We use CodeJail as the sandboxing facility,
but it needs to be configured specifically for Capa's use.

As a developer, you don't have to do anything to configure sandboxing if you
don't want to, and everything will operate properly, you just won't have
protection on that code.

If you want to configure sandboxing, you're going to use the `README from
CodeJail`__, with a few customized tweaks.

__ https://github.com/openedx/codejail/blob/master/README.rst


1. At the instruction to install packages into the sandboxed code, you'll
   need to install the requirements from requirements/edx-sandbox::

    $ pip install -r requirements/edx-sandbox/base.txt

2. You can configure resource limits in settings.py.  A CODE_JAIL setting is
   available, a dictionary.  The "limits" key lets you adjust the limits for
   CPU time, real time, and memory use.  Setting any of them to zero disables
   that limit::

    # in settings.py...
    CODE_JAIL = {
        # Configurable limits.
        'limits': {
            # How many CPU seconds can jailed code use?
            'CPU': 1,
            # How many real-time seconds will a sandbox survive?
            'REALTIME': 1,
            # How much memory (in bytes) can a sandbox use?
            'VMEM': 30000000,
        },
    }


That's it.  Once you've finished the CodeJail configuration instructions,
your course-hosted Python code should be run securely.