#!/usr/bin/env python

version = "1.2"
from flask import Flask, url_for, send_from_directory, render_template, make_response, request
from flask_restx import Resource, Api, reqparse
import redis
import configparser
import json

config = configparser.ConfigParser()
config.read('../etc/server.conf')
stats = config['global'].getboolean('stats')
stats_pubsub = config['global'].getboolean('stats_pubsub')
stats_public = config['global'].getboolean('stats_public')
score = 1
session = config['session'].getboolean('enable')
session_ttl = config['session'].get('ttl')
app = Flask(__name__)
app.url_map.strict_slashes = False
api = Api(app, version=version, title='hashlookup CIRCL API', description='![](https://www.circl.lu/assets/images/circl-logo.png)\n[CIRCL hash lookup](https://hashlookup.circl.lu/) is a public API to lookup hash values against known database of files. For more details about all the datasets included [visit the website of the project](https://www.circl.lu/services/hashlookup/). The API is accessible via HTTP ReST API and the API is also [described as an OpenAPI](https://hashlookup.circl.lu/swagger.json). A [documentation is available with](https://www.circl.lu/services/hashlookup/) with sample queries and software using hashlookup. An offline version as Bloom filter is also [available](https://circl.lu/services/hashlookup/#how-to-quickly-check-a-set-of-files-in-a-local-directory). The API can be tested live in the interface below.', doc='/', license='CC-BY', contact='info@circl.lu', ordered=True)

rdb = redis.Redis(host='127.0.0.1', port='6666', decode_responses=True)

def is_hex(s):
    try:
        int(s, 16)
        return True
    except ValueError:
        return False

def check_md5(value=None):
    if value is None or len(value) != 32:
        return False
    if not is_hex(value):
        return False
    k = value.upper()
    return k

def check_sha1(value=None):
    if value is None or len(value) != 40:
        return False
    if not is_hex(value):
        return False
    k = value.upper()
    return k

def check_sha256(value=None):
    if value is None or len(value) != 64:
        return False
    if not is_hex(value):
        return False
    k = value.upper()
    return k

def client_info():
    if request.environ.get('HTTP_X_FORWARDED_FOR') is None:
        ip = request.environ['REMOTE_ADDR']
    else:
        ip = request.environ['HTTP_X_FORWARDED_FOR']
    user_agent = request.headers.get('User-Agent')
    if request.environ.get('HTTP_AUTHORIZATION') is not None:
        auth = request.environ.get('HTTP_AUTHORIZATION')
    else:
        auth = None
    return ({'ip_addr': ip, 'user_agent': user_agent, 'auth': auth})

def pub_lookup(channel=None, k=None):
    if channel is None:
        return False
    if k is None:
        return False
    client = client_info()
    client['value'] = k
    rdb.publish(channel, json.dumps(client))
    return True

def get_session():
    if session is False:
        return False
    if request.headers.get('hashlookup_session') is None:
        return False
    session_name = request.headers.get('hashlookup_session')
    if not rdb.exists("session:{}".format(session_name)):
        return False
    print("Using session_name: {}".format(session_name))
    ttl = rdb.ttl("session:{}".format(session_name))
    return ttl

def calculate_trust(hobject=None):
    """Trust level is between 0 and 100. 50 means we don't know the trust. Above 50, the trust level is more important as the file has been seen on various sources."""
    if hobject is None:
        return False
    hashlookup_trust = 50
    if 'hashlookup:parent-total' in hobject:
        hashlookup_trust = hashlookup_trust + (5*hobject['hashlookup:parent-total'])
    if 'KnownMalicious' in hobject:
        hashlookup_trust = hashlookup_trust - 20
    if hashlookup_trust > 100:
        hashlookup_trust = 100
    hobject['hashlookup:trust'] = hashlookup_trust
    return hobject

@api.route('/lookup/md5/<string:md5>')
@api.doc(description="Lookup MD5.")
class lookup(Resource):
    def get(self, md5):
        if check_md5(value=md5) is False:
            return {'message': 'MD5 value incorrect, expecting a MD5 value in hex format'}, 400
        k = check_md5(value=md5)
        ttl = False
        if session:
            ttl = get_session()
        if not (rdb.exists("l:{}".format(k)) or rdb.exists("h:{}".format(k))):
            if stats:
                rdb.zincrby("s:nx:md5", score, k)
            if stats_pubsub:
                pub_lookup(channel='nx', k=k)
            if session and ttl is not False:
                session_key = "session:{}:nx".format(request.headers.get('hashlookup_session'))
                rdb.sadd(session_key, k)
                rdb.expire(session_key, ttl)
            return {'message': 'Non existing MD5', 'query': md5}, 404
        if stats:
            rdb.zincrby("s:exist:md5", score, k)
        if stats_pubsub:
            pub_lookup(channel='exist', k=k)
        if session and ttl is not False:
            session_key = "session:{}:exist".format(request.headers.get('hashlookup_session'))
            rdb.sadd(session_key, k)
            rdb.expire(session_key, ttl)
        if rdb.exists("h:{}".format(k)) and not rdb.exists("l:{}".format(k)):
            h = rdb.hgetall("h:{}".format(k))
            sha1 = k
        else:
            sha1 = rdb.get("l:{}".format(k))
            h = rdb.hgetall("h:{}".format(sha1))
        if "OpSystemCode" in h:
            if rdb.exists("h-OpSystemCode:{}".format(h['OpSystemCode'])):
                h['OpSystemCode'] = rdb.hgetall("h-OpSystemCode:{}".format(h['OpSystemCode']))
        if "ProductCode" in h:
            if rdb.exists("h-ProductCode:{}".format(h['ProductCode'])):
                h['ProductCode'] = rdb.hgetall("h-ProductCode:{}".format(h['ProductCode']))
        if rdb.exists("p:{}".format(sha1)):
            parents = []
            card = rdb.scard("p:{}".format(sha1))
            if card <= 15:
                p = rdb.smembers("p:{}".format(sha1))
            else:
                p = rdb.srandmember("p:{}".format(sha1), number=10)
            h['hashlookup:parent-total'] = card
            for parent in p:
                parent_details = rdb.hgetall("h:{}".format(parent))
                parents.append(parent_details)
            h['parents'] = parents
        if rdb.exists("c:{}".format(sha1)):
            children = []
            card = rdb.scard("c:{}".format(sha1))
            if card <= 15:
                c = rdb.smembers("c:{}".format(sha1))
            else:
                c = rdb.srandmember("c:{}".format(sha1), number=10)
            h['hashlookup:children-total'] = card
            for child in c:
                child_details = rdb.hgetall("h:{}".format(child))
                children.append(child_details)
            h['children'] = children
        h = calculate_trust(hobject=h)
        return h

@api.route('/lookup/sha1/<string:sha1>')
@api.doc(description="Lookup SHA-1.")
class lookup(Resource):
    def get(self, sha1):
        if check_sha1(value=sha1) is False:
            return {'message': 'SHA1 value incorrect, expecting a SHA1 value in hex format'}, 400
        k = check_sha1(value=sha1)
        ttl = False
        if session:
            ttl = get_session()
        if not rdb.exists("h:{}".format(k)):
            if stats:
                rdb.zincrby("s:nx:sha1", score, k)
            if stats_pubsub:
                pub_lookup(channel='nx', k=k)
            if session and ttl is not False:
                session_key = "session:{}:nx".format(request.headers.get('hashlookup_session'))
                rdb.sadd(session_key, k)
                rdb.expire(session_key, ttl)
            return {'message': 'Non existing SHA-1', 'query': sha1}, 404
        if stats:
            rdb.zincrby("s:exist:sha1", score, k)
        if stats_pubsub:
            pub_lookup(channel='exist', k=k)
        if session and ttl is not False:
            session_key = "session:{}:exist".format(request.headers.get('hashlookup_session'))
            rdb.sadd(session_key, k)
            rdb.expire(session_key, ttl)
        h = rdb.hgetall("h:{}".format(k))
        if "OpSystemCode" in h:
            if rdb.exists("h-OpSystemCode:{}".format(h['OpSystemCode'])):
                h['OpSystemCode'] = rdb.hgetall("h-OpSystemCode:{}".format(h['OpSystemCode']))
        if "ProductCode" in h:
            if rdb.exists("h-ProductCode:{}".format(h['ProductCode'])):
                h['ProductCode'] = rdb.hgetall("h-ProductCode:{}".format(h['ProductCode']))
        if rdb.exists("p:{}".format(k)):
            parents = []
            card = rdb.scard("p:{}".format(k))
            if card <= 15:
                p = rdb.smembers("p:{}".format(k))
            else:
                p = []
                p = rdb.srandmember("p:{}".format(k), number=10)
            h['hashlookup:parent-total'] = card
            for parent in p:
                parent_details = rdb.hgetall("h:{}".format(parent))
                parents.append(parent_details)
            h['parents'] = parents
        if rdb.exists("c:{}".format(k)):
            children = []
            card = rdb.scard("c:{}".format(k))
            if card <= 15:
                c = rdb.smembers("c:{}".format(k))
            else:
                c = rdb.srandmember("c:{}".format(k), number=10)
            h['hashlookup:children-total'] = card
            for child in c:
                child_details = rdb.hgetall("h:{}".format(child))
                children.append(child_details)
            h['children'] = children

        h = calculate_trust(hobject=h)
        return h

@api.route('/lookup/sha256/<string:sha256>')
@api.doc(description="Lookup SHA-256.")
class lookup(Resource):
    def get(self, sha256):
        if check_sha256(value=sha256) is False:
            return {'message': 'SHA-256 value incorrect, expecting a SHA-256 value in hex format'}, 400
        k = check_sha256(value=sha256)
        ttl = False
        if session:
            ttl = get_session()
        if not (rdb.exists("l:{}".format(k)) or rdb.exists("h:{}".format(k))):
            if stats:
                rdb.zincrby("s:nx:sha256", score, k)
            if stats_pubsub:
                pub_lookup(channel='nx', k=k)
            if session and ttl is not False:
                session_key = "session:{}:nx".format(request.headers.get('hashlookup_session'))
                rdb.sadd(session_key, k)
                rdb.expire(session_key, ttl)
            return {'message': 'Non existing SHA-256', 'query': sha256}, 404
        if stats:
            rdb.zincrby("s:exist:sha256", score, k)
        if stats_pubsub:
            pub_lookup(channel='exist', k=k)
        if session and ttl is not False:
            session_key = "session:{}:exist".format(request.headers.get('hashlookup_session'))
            rdb.sadd(session_key, k)
            rdb.expire(session_key, ttl)
        if rdb.exists("h:{}".format(k)) and not rdb.exists("l:{}".format(k)):
            h = rdb.hgetall("h:{}".format(k))
            sha1 = k
        else:
            sha1 = rdb.get("l:{}".format(k))
            h = rdb.hgetall("h:{}".format(sha1))
        if "OpSystemCode" in h:
            if rdb.exists("h-OpSystemCode:{}".format(h['OpSystemCode'])):
                h['OpSystemCode'] = rdb.hgetall("h-OpSystemCode:{}".format(h['OpSystemCode']))
        if "ProductCode" in h:
            if rdb.exists("h-ProductCode:{}".format(h['ProductCode'])):
                h['ProductCode'] = rdb.hgetall("h-ProductCode:{}".format(h['ProductCode']))
        if rdb.exists("p:{}".format(sha1)):
            parents = []
            card = rdb.scard("p:{}".format(sha1))
            if card <= 15:
                p = rdb.smembers("p:{}".format(sha1))
            else:
                p = rdb.srandmember("p:{}".format(sha1), number=10)
            h['hashlookup:parent-total'] = card
            for parent in p:
                parent_details = rdb.hgetall("h:{}".format(parent))
                parents.append(parent_details)
            h['parents'] = parents
        if rdb.exists("c:{}".format(sha1)):
            children = []
            card = rdb.scard("c:{}".format(sha1))
            if card <= 15:
                c = rdb.smembers("c:{}".format(sha1))
            else:
                c = rdb.srandmember("c:{}".format(sha1), number=10)
            h['hashlookup:children-total'] = card
            for child in c:
                child_details = rdb.hgetall("h:{}".format(child))
                children.append(child_details)
            h['children'] = children

        h = calculate_trust(hobject=h)
        return h


@api.route('/info')
@api.doc(description="Info about the hashlookup database")
class info(Resource):
    def get(self):
        info = {}
        lookup = rdb.info()
        info['nsrl-version'] = rdb.get('nsrl-version')
        info['stat:hashlookup_total_keys'] = lookup['estimate_keys[default]']
        info['stat:nsrl_modern_rds'] = rdb.get('stat:nsrl_modern_rds')
        info['stat:nsrl_legacy'] = rdb.get('stat:nsrl_legacy')
        info['stat:nsrl_ios'] = rdb.get('stat:nsrl_ios')
        info['stat:nsrl_android'] = rdb.get('stat:nsrl_android')
        info['hashlookup-version'] = version
        return info

@api.route('/bulk/md5')
@api.doc(description="Bulk search of MD5 hashes in a JSON array with the key \'hashes\'.")
class bulkmd5(Resource):
    def post(self):
        json_data = request.get_json(force=True)
        if not 'hashes' in json_data:
            return {'message': 'JSON format incorrect. An array of hashes in the key \'hashes\' is expected.'}, 404
        ret = []
        for val in json_data['hashes']:
            k = val.upper()
            if check_md5(value=k) is False:
                continue
            if not rdb.exists("l:{}".format(k)):
                if stats_pubsub:
                    pub_lookup(channel='nx', k=k)
                continue
            sha1 = rdb.get("l:{}".format(k))
            ret.append(rdb.hgetall("h:{}".format(sha1)))
            if stats:
                rdb.zincrby("s:exist:sha1", score, k)
            if stats_pubsub:
                pub_lookup(channel='exist', k=k)
        return ret

@api.route('/bulk/sha1')
@api.doc(description="Bulk search of SHA1 hashes in a JSON array with the \'hashes\'.")
class bulksha1(Resource):
    def post(self):
        json_data = request.get_json(force=True)
        if not 'hashes' in json_data:
            return {'message': 'JSON format incorrect. An array of hashes in the key \'hashes\' is expected.'}, 404
        ret = []
        for val in json_data['hashes']:
            k = val.upper()
            if check_sha1(value=k) is False:
                continue
            if not rdb.exists("h:{}".format(k)):
                if stats_pubsub:
                    pub_lookup(channel='nx', k=k)
                continue
            k = val.upper()
            ret.append(rdb.hgetall("h:{}".format(k)))
            if stats:
                rdb.zincrby("s:exist:sha1", score, k)
            if stats_pubsub:
                pub_lookup(channel='exist', k=k)
        return ret

@api.route('/session/create/<string:name>')
@api.doc(description="Create a session key to keep search context. The session is attached to a name. After the session is created, the header `hashlookup_session` can be set to the session name.")
class sessioncreate(Resource):
    def get(self, name):
        if name is None or len(name) > 120:
            return {'message': 'Expecting a name for the session'}, 400
        if session is False:
            return {'message': 'Session feature is not enabled'}, 500
        rdb.set('session:{}'.format(name), str(client_info()))
        rdb.expire('session:{}'.format(name), session_ttl)
        return {'message': 'Session {} created and session will expire in {} seconds'.format(name, session_ttl)}


@api.route('/session/get/<string:name>')
@api.doc(description="Return set of matching and non-matching hashes from a session.")
class sessioncreate(Resource):
    def get(self, name):
        if name is None or len(name) > 120:
            return {'message': 'Expecting a name for the session'}, 400
        if session is False:
            return {'message': 'Session feature is not enabled'}, 500
        if not rdb.exists('session:{}'.format(name)):
            return {'message': 'Non-existing session'}, 404
        nx = rdb.smembers('session:{}:nx'.format(name))
        exist = rdb.smembers('session:{}:exist'.format(name))
        ret = {}
        ret['nx'] = list(nx)
        ret['exist'] = list(exist)
        ret['info'] = rdb.get('session:{}'.format(name))
        return ret

@api.route('/stats/top')
@api.doc(description="Return the top 100 of most queried values.")
class stattop(Resource):
    def get(self):
        if stats_public is False:
            return {'message': 'Public statistics not enabled'}, 400
        ret = {}
        ret['nx'] = rdb.zrevrange("s:nx:sha1", 0, 100, withscores=True)
        for val in ret['nx']:
            if rdb.exists("h:{}".format(val[0])):
                ret['nx'].remove(val)
        exist = rdb.zrevrange("s:exist:sha1", 0, 100, withscores=True)
        ret['exist'] = []
        for value in exist:
            name = rdb.hget("h:{}".format(value[0]), "FileName")
            entry = {}
            entry['FileName'] = name
            entry['SHA-1'] = value
            ret['exist'].append(entry)
        return ret

if __name__ == '__main__':
        app.run(host='0.0.0.0')