Python 3.13.0 REPL loads local files unexpectedly, causing conflicts and security issues

[aleksa]

Bug report

Bug description:

Description

When starting the Python 3.13.0 REPL in a directory containing a file named code.py, the REPL attempts to load this local file instead of the standard library code module. This causes conflicts and errors when initializing the interactive environment. This is also a major security issue.

Steps to Reproduce

1. Create a directory and navigate to it
2. Create a file named code.py in this directory
3. Ensure Python 3.13.0 is installed (e.g., using pyenv)
4. Start the Python 3.13.0 REPL in this directory

Expected Behavior

The Python REPL should start normally, using the standard library code module for its interactive features.

Actual Behavior

The REPL fails to initialize properly, producing an error message indicating that it's attempting to use the local code.py file instead of the standard library module:

aleksa@aleksa:~/testing13$ python
Python 3.13.0 (main, Oct  8 2024, 16:45:05) [GCC 11.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
Failed calling sys.__interactivehook__
Traceback (most recent call last):
  File "<frozen site>", line 498, in register_readline
  File "/home/aleksa/.pyenv/versions/3.13.0/lib/python3.13/_pyrepl/readline.py", line 39, in <module>
    from . import commands, historical_reader
  File "/home/aleksa/.pyenv/versions/3.13.0/lib/python3.13/_pyrepl/historical_reader.py", line 26, in <module>
    from .reader import Reader
  File "/home/aleksa/.pyenv/versions/3.13.0/lib/python3.13/_pyrepl/reader.py", line 32, in <module>
    from . import commands, console, input
  File "/home/aleksa/.pyenv/versions/3.13.0/lib/python3.13/_pyrepl/console.py", line 153, in <module>
    class InteractiveColoredConsole(code.InteractiveConsole):
                                    ^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: module 'code' has no attribute 'InteractiveConsole' (consider renaming '/home/aleksa/testing13/code.py' since it has the same name as the standard library module named 'code' and the import system gives it precedence)
warning: can't use pyrepl: module 'code' has no attribute 'InteractiveConsole' (consider renaming '/home/aleksa/testing13/code.py' since it has the same name as the standard library module named 'code' and the import system gives it precedence)
>>>

Additional Context

• This behavior is not observed in Python 3.12.7
• The issue seems to be related to how Python 3.13.0 handles module imports in the REPL initialization process

System Information

• OS: Linux (Ubuntu 22.04)
• Python version: 3.13.0
• Installation method: pyenv

Possible Solution

The REPL initialization process should be modified to ensure it uses the standard library code module, regardless of local files in the current directory.

CPython versions tested on:

3.13

Operating systems tested on:

Linux

Linked PRs

• gh-125140: Remove the current directory from sys.path when using pyrepl #125212
• [3.13] gh-125140: Remove the current directory from sys.path when using pyrepl (GH-125212) #125224

[tomasr8]

Confirmed on current main as well. Weirdly enough, it does not seem to happen when I shadow some other stdlib modules which are also imported from _pyrepl/console.py

[hroncok]

Weirdly enough, it does not seem to happen when I shadow some other stdlib modules which are also imported from _pyrepl/console.py

Any chance this does not happen with abc, last, sys, os but happens with others? E.g. with dataclasses, I get:

$ python3.13
Python 3.13.0 (main, Oct  8 2024, 00:00:00) [GCC 13.3.1 20240913 (Red Hat 13.3.1-3)] on linux
Type "help", "copyright", "credits" or "license" for more information.
warning: can't use pyrepl: cannot import name 'dataclass' from 'dataclasses' (/home/.../exploit/dataclasses.py)
>>> 

I believe that some modules are loaded before $the current working directory is added to sys.path by the site module (?).

[ZeroIntensity]

Hmm, I wouldn't say this is a major security issue. I don't think the REPL is a very common attack vector, so I'm hesitant to add the security label.

cc @pablogsal (I'm not sure if you get notified when topic-repl is added.)

[aleksa]

This issue poses a significant security risk as it potentially allows malicious code to be executed without the user's knowledge or consent. The current functionality permits users to navigate the file tree and access the Python REPL, where arbitrary code can be run at the current privilege level.

As a user, I often utilize the Python REPL for quick calculations or other brief tasks. However, I would never assume that this action could damage the system, especially considering the risk depends on the current folder location. This misconception highlights the danger of the current implementation.

This vulnerability could be exploited for various malicious purposes, including:

• Phishing attacks
• Intentional system damage
• Unauthorized data access or manipulation

The risk is particularly concerning because users may inadvertently run harmful code while performing routine tasks, unaware of the potential consequences.

Given the severity of potential exploits and the ease with which users might unknowingly expose themselves to risk, I recommend prioritizing this issue for immediate attention and resolution.