harden: secure dynamic_imports.py

[anupamme]

Untrusted user input in importlib.import_module() function allows an attacker to load arbitrary code. Avoid dynamic values in importlib.import_module() or use a whitelist to prevent running untrusted code. This is defence-in-depth at src/openrouter/utils/dynamic_imports.py:12 rather than a vulnerability I can show is exploitable here — it makes the failure mode explicit and bounded. Close it freely if the pattern is intentional.

What changed

• src/openrouter/utils/dynamic_imports.py

Verification

No automated check could be run against this repository, so this change is unverified beyond review. Please treat it as a suggestion.

Regression test

The security boundary is maintained under adversarial input

Test

import pytest
from src.openrouter.utils.dynamic_imports import dynamic_import


@pytest.mark.parametrize("module_name", [
    "os",  # exploit: dangerous stdlib module
    "..os",  # boundary: path traversal attempt
    "collections",  # valid: safe stdlib module
])
def test_dynamic_import_rejects_untrusted_modules(module_name):
    """Invariant: dynamic_import must only load whitelisted/safe modules and reject dangerous ones."""
    try:
        result = dynamic_import(module_name)
    except (ImportError, ValueError, ModuleNotFoundError):
        # Expected safe behavior - module rejected
        return
    
    # If import succeeded, verify it's not a dangerous module
    dangerous_modules = {"os", "sys", "subprocess", "socket", "ctypes"}
    if hasattr(result, "__name__"):
        assert result.__name__ not in dangerous_modules, \
            f"Dangerous module '{module_name}' was loaded, violating security boundary"

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Automated security fix by OrbisAI Security