# -*- coding: utf-8 -*-
# Copyright © Cloud Linux GmbH & Cloud Linux Software, Inc 2010-2022 All Rights Reserved
#
# Licensed under CLOUD LINUX LICENSE AGREEMENT
# http://cloudlinux.com/docs/LICENSE.TXT
#
import glob
import importlib.util
import logging
import os
import stat
import sys
from .helpers import LISTENERS_DIRECTORY
logger = logging.getLogger(__name__)
from .modify_domain_hook import ModifyDomainHook
from .modify_admin_hook import ModifyAdminHook
from .modify_user_hook import ModifyUserHook
from .modify_package_hook import ModifyPackageHook
def _is_root_owned_unwritable(filepath):
"""
Return True only if `filepath` is a regular file owned by root (uid 0) and
not group- or world-writable. Used to gate a listener before its top-level
code is exec_module()'d as root: a *.py (or a symlink whose real target) a
non-root principal can write is refused rather than executed. os.stat
follows symlinks, so it stats the real inode whose code would run.
"""
try:
st = os.stat(filepath)
except OSError:
return False
return (stat.S_ISREG(st.st_mode) and
st.st_uid == 0 and
not (st.st_mode & (stat.S_IWGRP | stat.S_IWOTH)))
def import_file(filepath):
# Fast path: see if the module has already been imported.
name = os.path.basename(filepath)[:-3]
if name in sys.modules:
return sys.modules[name]
# Defense-in-depth: exec_module() below runs the listener's top-level code
# in this root process. Refuse a listener that is not root-owned or is
# group/world-writable, so an attacker-influenceable file is not executed.
if not _is_root_owned_unwritable(filepath):
logger.warning('refusing to load listener %s: not root-owned or '
'group/world-writable', filepath)
return None
# If any of the following calls raises an exception,
# there's a problem we can't handle -- let the caller handle it.
module_spec = importlib.util.spec_from_file_location(name, filepath)
if module_spec is None:
raise ImportError(f"Can't find module {name} at {filepath}")
# Load the module, potentially raising ImportError if the module cannot be loaded
module = importlib.util.module_from_spec(module_spec)
module_spec.loader.exec_module(module)
# Add the module to sys.modules
sys.modules[name] = module
return module
# automatically scan directory for universal hooks
for hook_py in glob.glob(os.path.join(LISTENERS_DIRECTORY, '*.py')):
import_file(hook_py)
__all__ = (
'ModifyDomainHook',
'ModifyAdminHook',
'ModifyUserHook',
'ModifyPackageHook',
)
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