"""
Countermeasures driver program - executes one or more countermeasures

Copyright 2023 Fortinet, Inc. All Rights Reserved.
[email protected]

TODO:
 - global block file to prevent all countermeasures from running?
 - sudo access validation
 - run time limits
"""

try:
    import argparse
except:
    import p_argparse as argparse
try:
    # Python 2.x
    import ConfigParser as configparser
except:
    # Python 3.x
    import configparser
try:
    import json
except ImportError:
    import simplejson as json
import p_importlib
import logging
import logging.handlers
import os
import os.path
import subprocess
import sys
import tarfile
import tempfile
import time
import traceback
import types
from datetime import datetime
try:
    # Python 2.x
    import urllib2
except:
    import urllib.request as urllib2
try:
    # Python 2.x
    import urlparse
except:
    import urllib.parse as urlparse

import zipfile

import aggregator
import agent_util
from .plugins.CountermeasurePlugin import JsonPlugin

MAX_OUTPUT_LENGTH = 100 * 1024


# Backported for Python 2.4 support
def any(iterable):
    for element in iterable:
        if element:
            return True
    return False


def load_plugins():
    """
    Dynamically load all available Countermeasure plugins, in both the application default
    and the customer's local custom plugin directory
    """

    log = setup_logging("countermeasure")

    plugins = {}

    for directory in (os.path.join(LIB_DIR, "countermeasures", "plugins"), BASE_CUSTOM_PLUGIN_DIR):
        if not os.path.exists(directory):
            continue
        log.info("Loading Countermeasure plugins from %s" % directory)
        sys.path.append(directory)
        for mod_name in os.listdir(directory):
            if mod_name.endswith(".py") and not mod_name.startswith("__"):
                try:
                    mod = p_importlib.import_module(mod_name[:-3])
                except:
                    log.error("Unable to import plugin %s: %s" % (mod_name, traceback.format_exc()))
                    continue
                for name, obj in list(mod.__dict__.items()):
                    if ((sys.version_info[0] == 3 and type(obj) == type) or (sys.version_info[0] == 2 and type(obj) == types.ClassType)) and name.endswith("Countermeasure"):
                        try:
                            plugin = obj()
                            plugins[plugin.textkey] = plugin
                        except:
                            log.error("Unable to instantiate plugin %s: %s" % (mod_name, traceback.format_exc()))
            if mod_name.endswith('.json'):
                try:
                    json_counter = open(os.path.join(directory, mod_name))
                except Exception:
                    log.error('Unable to open %s' % os.path.join(directory, mod_name))
                    log.error(traceback.format_exc())
                    continue
                file_content = json_counter.read()
                json_counter.close()
                try:
                    counter_data = json.loads(file_content)
                except Exception:
                    log.error('%s file is not a valid json file to be read' % mod_name)
                    log.error(traceback.format_exc())
                    continue
                required_fields = ['name', 'textkey', 'command', 'author']
                existing_keys = counter_data.keys()
                success = True
                for key in required_fields:
                    if key not in existing_keys or not counter_data.get(key):
                        log.error('%s is missing from the countermeasure declaration of %s' % (key, mod_name))
                        success = False
                        break
                if not success:
                    continue
                try:
                    max_runtime = int(counter_data.get('max_runtime'))
                except:
                    log.error('max runtime %s is not valid' % (counter_data.get('max_runtime')))
                    max_runtime = None
                try:
                    max_frequency = int(counter_data.get('max_frequency'))
                except:
                    log.error('max frequency %s is not valid' % (counter_data.get('max_frequency')))
                    max_frequency = None
                textkey = counter_data.get('textkey')
                plugin = JsonPlugin(counter_data.get('command'))
                plugin.textkey = counter_data.get('textkey')
                plugin.name = counter_data.get('name')
                plugin.description = counter_data.get('description')
                plugin.wall_announce_delay = counter_data.get('wall_announce_delay')
                plugin.author = counter_data.get('author')
                plugin.max_runtime = counter_data.get('max_runtime')
                plugin.max_frequency = counter_data.get('max_frequency')
                plugins[textkey] = plugin

    return plugins


def load_agent_config():

    agent_config_file = os.path.join(BASE_CONFIG_DIR, PKG_DIR, "%s_agent.cfg" % BRAND)
    config_file = configparser.ConfigParser()
    config_file.read(agent_config_file)
    return config_file


def setup_logging(name):

    log_file = os.path.join(BASE_LOG_DIR, PKG_DIR, "countermeasure.log")

    root_logger = logging.getLogger(name)
    agg_logger = logging.getLogger("Client")
    handler = logging.handlers.RotatingFileHandler(log_file, 'a', maxBytes=5 * 1024**2, backupCount=5)
    handler.setFormatter(logging.Formatter('%(process)d) '
                                           '%(asctime)s - '
                                           '%(name)s - '
                                           '%(levelname)s - '
                                           '%(message)s'))
    root_logger.addHandler(handler)
    agg_logger.addHandler(handler)

    # If we have a TTY, add a stdout handler
    if sys.stdin.isatty():
        root_logger.addHandler(logging.StreamHandler())
    root_logger.setLevel(logging.INFO)
    agg_logger.setLevel(logging.INFO)
    return root_logger


def set_last_execution(textkey):

    last_execution_directory = os.path.join(BASE_DATA_DIR, PKG_DIR, "countermeasures/last_execution")
    if not os.path.exists(last_execution_directory):
        os.makedirs(last_execution_directory)

    os.system("touch %s" % os.path.join(last_execution_directory, textkey))


def get_last_execution(textkey):

    last_execution_directory = os.path.join(BASE_DATA_DIR, PKG_DIR, "countermeasures/last_execution")
    if not os.path.exists(last_execution_directory):
        os.makedirs(last_execution_directory)

    filename = os.path.join(last_execution_directory, textkey)
    if not os.path.exists(filename):
        return 0
    stat = os.stat(filename)
    return stat.st_mtime


def install_plugins(url):

    log = setup_logging("countermeasure")
    log.info("\nFetching remote plugins from %s" % url)

    f = tempfile.NamedTemporaryFile(delete=False)
    num_installed = 0
    ext = url.split(".")[-1]
    fname = url.split("/")[-1]
    if not os.path.exists(BASE_CUSTOM_PLUGIN_DIR):
        os.system('mkdir %s' % BASE_CUSTOM_PLUGIN_DIR)
    try:
        r = urllib2.urlopen(url)
        if "content-disposition" in r.info():
            ext = r.info().getheader("content-disposition").split(".")[-1]
        f.write(r.read())
        f.close()
    except:
        log.error("Unable to download URL: %s" % traceback.format_exc())
        return

    if ext in ("tar", "tgz"):
        try:
            t = tarfile.open(f.name)
            for file in t.getnames():
                if file.endswith(".py") or file.endswith('.json'):
                    log.info("  Installing plugin %s" % file)
                    t.extract(file, BASE_CUSTOM_PLUGIN_DIR)
                    num_installed += 1
        except:
            log.error("Unable to extract tar contents: %s" % traceback.format_exc())
    elif ext == "zip":
        try:
            z = zipfile.ZipFile(f.name)
            for file in z.namelist():
                if file.endswith(".py") or file.endswith(".json"):
                    log.info("  Installing plugin %s" % file)
                    z.extract(file, BASE_CUSTOM_PLUGIN_DIR)
                    num_installed += 1
        except:
            log.error("Unable to extract zip contents: %s" % traceback.format_exc())
    elif ext == "py" or ext == "json":
        log.info("  Installing plugin %s" % fname)
        os.system("cp %s %s" % (f.name, os.path.join(BASE_CUSTOM_PLUGIN_DIR, fname)))
        num_installed += 1
    else:
        log.error("Unable to install Countermeasure, unknown extension: %s" % ext)

    if num_installed:
        log.info("\nInstalled %s Countermeasure plugins" % num_installed)

    os.system("rm -f %s" % f.name)


def list_plugins():
    plugins = load_plugins()

    pairs = []
    for textkey, plugin in plugins.items():
        pairs.append((plugin.name, plugin.author or "", plugin.description))
    pairs.sort()

    max_name_len = max([len(p[0]) for p in pairs])
    max_author_len = max([len(p[1]) for p in pairs])

    print("\nAvailable Countermeasures")
    print("=========================\n")
    fmt = "%-" + str(max_name_len+3) + "s %-" + str(max_author_len+3) +"s %s"
    print(fmt % ("Name", "Author", "Description"))
    print("-" * 80)
    for textkey, author, description in pairs:
        print(fmt % (textkey, author, description))
    print("")


def validate_plugins():
    plugins = load_plugins()

    pairs = []
    for textkey, plugin in plugins.items():
        output = plugin.validate()
        if output:
            pairs.append((plugin.name, output))

    if pairs:
        pairs.sort()
        max_len = max([len(p[0]) for p in pairs])
        print("\nInvalid Countermeasures")
        print("=========================")
        fmt = "%-" + str(max_len+3) + "s %s"
        for textkey, description in pairs:
            print(fmt % (textkey, description))
    else:
        print("\nAll plugins are valid.")
    print("")


def validate_sudo():

    plugins = load_plugins()

    for textkey, plugin in plugins.items():
        if plugin.sudo_requirements:
            print("\nVerifying sudo requirements for %s" % textkey)
            devnull = open("/dev/null", "w")
            for app in plugin.sudo_requirements:

                # If the app is a list, then we just need at least one of these to be available
                if type(app) == list:
                    valid = any([subprocess.call(("sudo -n -l %s" % subapp).split(), stdout=devnull, stderr=devnull) == 0 for subapp in app])

                # If not a list, just check one item
                else:
                    valid = subprocess.call(("sudo -n -l %s" % app).split(), stdout=devnull, stderr=devnull) == 0

                print("  %-30s  %s" % (("%s:%s" % (textkey, app)), valid and "Pass" or "Missing Permissions"))
            print("")
            devnull.close()


def execute(hash, textkeys, metadata_file=None):

    # Setup logging and get config file
    log = setup_logging("countermeasure %s" % hash)
    config = load_agent_config()

    # Read and parse any metadata if given
    cm_metadata = {}
    if metadata_file:
        try:
            f = open(metadata_file, 'r')
            metadata_contents = f.read()
            f.close()
            cm_metadata = json.loads(metadata_contents)
            os.remove(metadata_file)
        except Exception:
            log.error("Problem while proccessing metadata:")
            log.error(traceback.format_exc())
            cm_metadata = {}

    # Get available plugins
    plugins = load_plugins()
    proxy_info = {}
    if config.has_section('agent_proxy'):
        proxy_info = config['agent_proxy']

    # Iterate through the plugin textkeys, executing each one in succession
    for textkey in textkeys:
        if textkey not in plugins:
            print("Unable to execute unknown plugin %s" % textkey)
            log.error("Unable to execute unknown plugin %s" % textkey)
            current_time = datetime.utcnow().strftime("%Y-%m-%d %H:%M:%S")
            report_output(plugin_textkey=textkey,
                          server_key=config.get('agent', 'server_key'),
                          aggregator_url=config.get(
                              'agent', 'aggregator_url').lower(),
                          agent_version=config.get('agent', 'version'),
                          output=[{'timestamp': current_time, 'format': 'text',
                                  'output': 'Unable to execute plugin %s' % textkey}],
                          hash=hash,
                          return_code=1,
                          status='error',
                          proxy_info=proxy_info)
            continue

        plugin = plugins[textkey]
        plugin.set_metadata(cm_metadata)

        # Check how recently the countermeasure has been run
        last_execution = time.time() - get_last_execution(textkey)
        if plugin.max_frequency and last_execution < plugin.max_frequency:
            log.warning("%s countermeasure skipped, ran too %d seconds ago" % (textkey, last_execution))
            continue

        print("Executing %s" % textkey)
        log.info("Executing %s" % textkey)

        # Set last execution time to current time
        set_last_execution(textkey)

        # Run prepare operation
        plugin.prepare()

        # Post wall message if needed
        if plugin.wall_announce_delay is not None:
            os.system("wall 'Executing %s countermeasure'" % textkey)
            if plugin.wall_announce_delay:
                time.sleep(plugin.wall_announce_delay)

        # Execute the plugin
        try:
            plugin.run()
            plugin.status = "success"
        except:
            plugin.status = "error"
            plugin.output = [{"timestamp": datetime.utcnow().strftime("%Y-%m-%d %H:%M:%S"),
                              "format": "text",
                              "output": "Exception executing plugin: %s" % traceback.format_exc()}]

        # Truncate output if it's too long
        if len(plugin.output) > MAX_OUTPUT_LENGTH:
            plugin.output = plugin.output[:MAX_OUTPUT_LENGTH]
        proxy_info = {}
        if config.has_section('agent_proxy'):
            proxy_info = config['agent_proxy']
        # Report the output
        report_output(
            plugin_textkey=plugin.textkey,
            server_key=config.get('agent', 'server_key'),
            aggregator_url=config.get('agent', 'aggregator_url').lower(),
            agent_version=config.get('agent', 'version'),
            output=plugin.output,
            return_code=plugin.return_code,
            hash=hash,
            status=plugin.status,
            proxy_info=proxy_info)
        log.info("Completed countermeasure %s" % textkey)


def report_output(**kwargs):
    aggregator_url = kwargs.get('aggregator_url')
    server_key = kwargs.get('server_key')
    agent_version = kwargs.get('agent_version')
    if not aggregator_url.startswith("http"):
        try:
            host, port = aggregator_url.split(":")
            if port in ("443", "8443"):
                aggregator_url = "https://" + aggregator_url
            else:
                aggregator_url = "http://" + aggregator_url
        except:
            aggregator_url = "https://" + aggregator_url
    aggregator_url = urlparse.urljoin(aggregator_url, "/v2/countermeasure")
    payload = {"countermeasure_textkey": kwargs.get('plugin_textkey'),
               "server_key": server_key,
               "incident_hash": kwargs.get('hash'),
               "output": kwargs.get('output'),
               "return_code": kwargs.get('return_code'),
               "status": kwargs.get('status'),
               }
    proxy_info = kwargs.get('proxy_info')
    aggregator_client = aggregator.Client(aggregator_url, agent_version, server_key, proxy_config=proxy_info)
    aggregator_client.call("countermeasure", payload)


def main():

    parser = argparse.ArgumentParser()
    parser.add_argument("action", choices=["execute", "list_plugins", "install_plugins", "validate_plugins", "validate_sudo"])
    parser.add_argument("--url", required=False, help="URL to download plugins from")
    parser.add_argument("--hash", required=False, help="Incident hash")
    parser.add_argument("--textkeys", required=False, nargs="+", help="CounterMeasure plugin textkeys to execute")
    parser.add_argument("--metadata-file", required=False, help="Path to file containing JSON metadata that will be passed to plugin")

    args = parser.parse_args()

    # Perform logical validation to make sure we got the correct arguments based on the action type
    if args.action == "execute" and (args.hash == None or args.textkeys == None):
        print("ERROR: Need to provide --hash and --textkey arguments\n")
        parser.print_help()
        sys.exit(1)
    elif args.action == "install_plugins" and args.url == None:
        print("ERROR: Need to provide --url argument\n")
        parser.print_help()
        sys.exit(1)

    # Dispatch to action methods
    if args.action == "execute":
        execute(args.hash, args.textkeys, args.metadata_file)
    elif args.action == "list_plugins":
        list_plugins()
    elif args.action == "install_plugins":
        install_plugins(args.url)
    elif args.action == "validate_plugins":
        validate_plugins()
    elif args.action == "validate_sudo":
        validate_sudo()