Mini Shell

#!/opt/cloudlinux/venv/bin/python3 -bb
#
# Copyright © Cloud Linux GmbH & Cloud Linux Software, Inc 2010-2024 All Rights Reserved
#
# Licensed under CLOUD LINUX LICENSE AGREEMENT
# http://cloudlinux.com/docs/LICENSE.TXT

import argparse
import enum
import shutil
import sys
from dataclasses import dataclass
from pathlib import Path
from typing import Callable

import logs
from clflags.config import DEFAULT_FLAGS_STORAGE_PATH

ENABLED_FEATURES_DIR = '/etc/cagefs/enabled_features'

logger = logs.setup_logger('feature_manager',
                           '/var/log/cloudlinux/cagefs.log')


class FlagBehavior(enum.Enum):
    """
    Defines the behavior of a CloudLinux Server Flag
    based on the presence of a file. The existence of this flag
    not only indicates that the 'feature' is enabled
    but could also mean it is explicitly disabled by creating the file.
    """
    ENABLE_ON_PRESENT = enum.auto()
    DISABLE_ON_PRESENT = enum.auto()


@dataclass
class Flag:
    """
    Represents a CloudLinux Server Flag
    typically located at /opt/cloudlinux/flags/enabled-flags.d/
    with a specific behavior based on a file existence.
    """
    flag_name: str
    flag_behavior: FlagBehavior

    @property
    def enabled(self) -> bool:
        flag_path = Path(DEFAULT_FLAGS_STORAGE_PATH, f'{self.flag_name}.flag')
        flag_exists = flag_path.exists()

        if self.flag_behavior == FlagBehavior.ENABLE_ON_PRESENT:
            return flag_exists
        elif self.flag_behavior == FlagBehavior.DISABLE_ON_PRESENT:
            return not flag_exists
        else:
            raise RuntimeError('Invalid value for the "flag_behavior" attribute')


@dataclass
class CageFsFeature:
    """
    Represents a feature within the CageFS file system.
    """
    name: str
    description: str
    handler: Callable
    flag: Flag

    @property
    def feature_marker_path(self) -> Path:
        """
        Returns the path to the CageFS feature marker file.
        """
        return Path(ENABLED_FEATURES_DIR, self.name)

    @property
    def enabled(self) -> bool:
        """
        Determines if the CageFS feature is enabled based on the existence
        of its feature marker file and CloudLinux Server Flag status.
        """
        return self.feature_marker_path.exists() and self.flag.enabled


class CageFsFeatureManager:
    """
    Manages a collection of CageFS features.
    """

    def __init__(self, features: list[CageFsFeature]):
        self.features: list[CageFsFeature] = features

    def enable(self):
        for feature in self.features:
            self._enable_feature(feature)

    def sync(self):
        for feature in self.features:
            self._sync_feature(feature)

    def _enable_feature(self, feature: CageFsFeature):
        feature.feature_marker_path.touch()

    def _sync_feature(self, feature: CageFsFeature):
        feature.handler(feature.enabled)


def handle_dbus_hardening(is_enabled: bool):
    """
    Handles the hardening of D-Bus configuration based on the enabled state.
    Essentially, just copies/removes the config file to/from the appropriate place.
    """
    config_name = 'cagefs-dbus-hardening.conf'
    local_path = Path('/usr/share/cagefs/configs/dbus', config_name)
    installed_path = Path('/etc/dbus-1/system.d', config_name)

    if is_enabled:
        if not installed_path.exists() and installed_path.parent.exists():
            shutil.copy2(local_path, installed_path)
    else:
        installed_path.unlink(missing_ok=True)


# List of available CageFS features
FEATURES = [
    CageFsFeature(
        name='dbus-hardening',
        description="Restrict user's capability to communicate "
                    "with systemd via D-Bus using certain methods",
        handler=handle_dbus_hardening,
        flag=Flag(
            flag_name='disable-dbus-hardening',
            flag_behavior=FlagBehavior.DISABLE_ON_PRESENT,
        ),
    ),
    # ... Add new features here ...
]


def enable(features: list[CageFsFeature]):
    """
    Enable specified CageFS features.
    """
    manager = CageFsFeatureManager(features)
    manager.enable()


def sync():
    """
    Synchronize the state of CageFS featues based on their current enabled status.
    """
    manager = CageFsFeatureManager(FEATURES)
    manager.sync()


def main():
    parser = argparse.ArgumentParser(
        description='Available manipulations with CageFS features')
    subparsers = parser.add_subparsers(dest='command', help='Available commands')

    # Enable command parser
    parser_enable = subparsers.add_parser('enable', help='Enable CageFS features')
    for feature in FEATURES:
        parser_enable.add_argument(
            f'--{feature.name}',
            action='store_true',
            help=feature.description,
        )

    # Sync command parser
    subparsers.add_parser(
        'sync', help='Sync CageFS features based on the state of the feature flags')

    args = parser.parse_args()

    try:
        match args.command:
            case 'enable':
                features = [feature for feature in FEATURES
                            if getattr(args, feature.name.replace('-', '_'))]
                if not features:
                    parser.error('At least one feature is required for the "enable" command')

                enable(features)
            case 'sync':
                sync()
            case _:
                parser.print_help()
                return 1
    except Exception as e:
        logger.error('An error occurred during manipulations with CageFS features:',
                     exc_info=e)
        return 1


if __name__ == '__main__':
    sys.exit(main())