#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# Lookup IP or CIDR block for known fingerprints and X.509 subjects via HTTP API /query/149.13.30.0/24
# Lookup fingerprint of certificate where seen /cquery/16c25d401f35dd52fb4aec85eb1f1a28ce16f961
#
# Software is free software released under the GNU General Public License version 3 and later
#
# Copyright (c) 2015 Alexandre Dulaunoy - a@foo.be

import redis
import sys
import netaddr
import json
import re
import os

import M2Crypto

from tornado.concurrent import run_on_executor
from concurrent.futures import ThreadPoolExecutor

import tornado.httpserver
import tornado.ioloop
import tornado.options
import tornado.web

from tornado.options import define, options
define("port", default=8888, help="run on the given port", type=int)
certrepo = '/data/certs{}'
ipmaxsize = 512  # /23
servername = 'SSL Certificate API - https://github.com/adulau/crl-monitor'


def checksha1(value=False):
    if value is False or len(value) != 40:
        return False
    try:
        int(value, 16)
    except ValueError:
        return False

    return True


def bpath(ha=None, level=6):
    if ha is None:
        return False
    fn = ""
    for i in range(0, level * 2, 2):
        fn = fn + "/" + ha[i:2 + i]
    return fn


class SSLQueryHandler(tornado.web.RequestHandler):

    # Default value in Python 3.5
    # https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.ThreadPoolExecutor
    nb_threads = tornado.process.cpu_count() * 5
    executor = ThreadPoolExecutor(nb_threads)

    @run_on_executor
    def run_request(self, q):
        try:
            # Redis structure Set of (FP) per IP
            r = redis.StrictRedis(host='127.0.0.1', port=8323)
        except:
            print("Unable to connect to the Redis server")
            sys.exit(255)
        subnets = [q]
        out = {}
        for subnet in subnets:
            if re.findall(r":", subnet):
                self.clear()
                self.set_status(400)
                self.finish('IPv6 is not (yet) supported')
                continue
            try:
                iplist = netaddr.IPNetwork(subnet)
            except:
                self.clear()
                self.set_status(400)
                self.finish('Incorrect format')
                continue

            if iplist.size > ipmaxsize:
                self.clear()
                self.set_status(400)
                self.finish('Maximum CIDR block size reached >/23')

                if not self._finished:
                    self.finish()
            for ip in iplist:
                s = r.smembers(ip)
                if s:
                    out[str(ip)] = {}
                    out[str(ip)]['certificates'] = []
                    out[str(ip)]['subjects'] = {}
                    for fingerprint in s:
                        subjects = r.smembers(fingerprint)
                        out[str(ip)]['certificates'].append(fingerprint)
                        if subjects:
                            out[str(ip)]['subjects'][fingerprint] = {}
                            out[str(ip)]['subjects'][fingerprint]['values'] = []
                            for subject in subjects:
                                    out[str(ip)]['subjects'][fingerprint]['values'].append(subject)

        if not self._finished:
            self.set_header('Content-Type', 'application/json')
            self.set_header('Server', servername)
            return json.dumps(out)

        def get(self, q):
            print("Query:", q)
            try:
                r = yield self.run_request(q)
                self.write(r)
            except Exception as e:
                print('Something went wrong with {}:\n{}'.format(q, e))


class CertificateQueryHandler(tornado.web.RequestHandler):

    # Default value in Python 3.5
    # https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.ThreadPoolExecutor
    nb_threads = tornado.process.cpu_count() * 5
    executor = ThreadPoolExecutor(nb_threads)

    @run_on_executor
    def run_request(self, q):
        try:
            r = redis.StrictRedis(host='127.0.0.1', port=8323)
        except:
            print("Unable to connect to the Redis server")
            sys.exit(255)
        fp = q.lower()
        if not checksha1(value=fp):
            self.clear()
            self.set_status(400)
            self.finish('Incorrect format of the certificate fingerprint (expected SHA1 in hex format)')

        out = {}
        out['certificate'] = fp
        out['seen'] = []
        ips = r.smembers('s:{}'.format(fp))
        out['hits'] = len(ips)
        for ip in ips:
                out['seen'].append(ip)

        if not self._finished:
            self.set_header('Content-Type', 'application/json')
            self.set_header('Server', servername)
            return json.dumps(out)

    def get(self, q):
        print("Query:", q)
        try:
            r = yield self.run_request(q)
            self.write(r)
        except Exception as e:
            print('Something went wrong with {}:\n{}'.format(q, e))


class FetchCertificateHandler(tornado.web.RequestHandler):

    # Default value in Python 3.5
    # https://docs.python.org/3/library/concurrent.futures.html#concurrent.futures.ThreadPoolExecutor
    nb_threads = tornado.process.cpu_count() * 5
    executor = ThreadPoolExecutor(nb_threads)

    @run_on_executor
    def run_request(self, q):
        # ICSI data
        try:
            ricsi = redis.StrictRedis(host='localhost', port=6380, db=5)
        except:
            print("Unable to connect to the Redis ICSI notary server")

        fp = q.lower()
        if not checksha1(value=fp):
            self.clear()
            self.set_status(400)
            self.finish('Incorrect format of the certificate fingerprint (expected SHA1 in hex format)')

        certpath = bpath(ha=fp)
        certpath = os.path.join(certpath, fp)
        certpath = certrepo.format(certpath)
        if not os.path.exists(certpath):
            self.clear()
            self.set_status(400)
            self.finish('Not existing certificate')

        cert = M2Crypto.X509.load_cert(certpath, M2Crypto.X509.FORMAT_DER)
        out = {}
        out['pem'] = cert.as_pem()
        out['info'] = {}
        out['info']['issuer'] = cert.get_issuer().as_text()
        out['info']['subject'] = cert.get_subject().as_text()
        out['info']['fingerprint'] = cert.get_fingerprint(md='sha1')
        out['info']['keylength'] = cert.get_pubkey().get_rsa().__len__()
        out['info']['key'] = cert.get_pubkey().get_rsa().as_pem()
        out['info']['not_before'] = cert.get_not_before().get_datetime().isoformat()
        out['info']['not_after'] = cert.get_not_after().get_datetime().isoformat()
        out['info']['extension'] = {}
        extcount = cert.get_ext_count()

        for i in range(0, extcount):
                out['info']['extension'][cert.get_ext_at(i).get_name()] = cert.get_ext_at(i).get_value()
        if ricsi.exists(fp):
                icsi = ricsi.hgetall(fp)
                out['icsi'] = icsi
        if not self._finished:
            self.set_header('Content-Type', 'application/json')
            self.set_header('Server', servername)
            return json.dumps(out)

    def get(self, q):
        print("Query:", q)
        try:
            r = yield self.run_request(q)
            self.write(r)
        except Exception as e:
            print('Something went wrong with {}:\n{}'.format(q, e))


def main():
    tornado.options.parse_command_line()
    app = tornado.web.Application(handlers=[
        (r"/query/(.*)", SSLQueryHandler),
        (r"/cquery/(.*)", CertificateQueryHandler),
        (r"/cfetch/(.*)", FetchCertificateHandler)
    ])
    http_server = tornado.httpserver.HTTPServer(app)
    http_server.listen(options.port)
    tornado.ioloop.IOLoop.instance().start()


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