# Copyright (c) 2009-2014 Upi Tamminen <desaster@gmail.com>
# See the COPYRIGHT file for more information

import twisted
from twisted.cred import portal
from twisted.conch import avatar, interfaces as conchinterfaces
from twisted.conch.ssh import factory, userauth, connection, keys, session, transport
from twisted.python import log
from zope.interface import implements

import os
import time
import ConfigParser

from kippo.core import ttylog, utils
from kippo.core.config import config
import kippo.core.auth
import kippo.core.honeypot
import kippo.core.ssh
import kippo.core.protocol
from kippo import core

from twisted.conch.ssh.common import NS, getNS
class HoneyPotSSHUserAuthServer(userauth.SSHUserAuthServer):
    def serviceStarted(self):
        userauth.SSHUserAuthServer.serviceStarted(self)
        self.bannerSent = False

    def sendBanner(self):
        if self.bannerSent:
            return
        cfg = config()
        if not cfg.has_option('honeypot', 'banner_file'):
            return
        try:
            data = file(cfg.get('honeypot', 'banner_file')).read()
        except IOError:
            print 'Banner file %s does not exist!' % \
                cfg.get('honeypot', 'banner_file')
            return
        if not data or not len(data.strip()):
            return
        data = '\r\n'.join(data.splitlines() + [''])
        self.transport.sendPacket(
            userauth.MSG_USERAUTH_BANNER, NS(data) + NS('en'))
        self.bannerSent = True

    def ssh_USERAUTH_REQUEST(self, packet):
        self.sendBanner()
        return userauth.SSHUserAuthServer.ssh_USERAUTH_REQUEST(self, packet)

# As implemented by Kojoney
class HoneyPotSSHFactory(factory.SSHFactory):
    services = {
        'ssh-userauth': HoneyPotSSHUserAuthServer,
        'ssh-connection': connection.SSHConnection,
        }

    # Special delivery to the loggers to avoid scope problems
    def logDispatch(self, sessionid, msg):
        for dblog in self.dbloggers:
            dblog.logDispatch(sessionid, msg)

    def __init__(self):
        cfg = config()

        # protocol^Wwhatever instances are kept here for the interact feature
        self.sessions = {}

        # for use by the uptime command
        self.starttime = time.time()

        # load db loggers
        self.dbloggers = []
        for x in cfg.sections():
            if not x.startswith('database_'):
                continue
            engine = x.split('_')[1]
            dbengine = 'database_' + engine
            lcfg = ConfigParser.ConfigParser()
            lcfg.add_section(dbengine)
            for i in cfg.options(x):
                lcfg.set(dbengine, i, cfg.get(x, i))
            lcfg.add_section('honeypot')
            for i in cfg.options('honeypot'):
                lcfg.set('honeypot', i, cfg.get('honeypot', i))
            print 'Loading dblog engine: %s' % (engine,)
            dblogger = __import__(
                'kippo.dblog.%s' % (engine,),
                globals(), locals(), ['dblog']).DBLogger(lcfg)
            log.startLoggingWithObserver(dblogger.emit, setStdout=False)
            self.dbloggers.append(dblogger)

    def buildProtocol(self, addr):
        cfg = config()

        # FIXME: try to mimic something real 100%
        t = HoneyPotTransport()

        if cfg.has_option('honeypot', 'ssh_version_string'):
            t.ourVersionString = cfg.get('honeypot','ssh_version_string')
        else:
            t.ourVersionString = "SSH-2.0-OpenSSH_5.1p1 Debian-5"

        t.supportedPublicKeys = self.privateKeys.keys()

        if not self.primes:
            ske = t.supportedKeyExchanges[:]
            ske.remove('diffie-hellman-group-exchange-sha1')
            t.supportedKeyExchanges = ske

        t.factory = self
        return t

class HoneyPotRealm:
    implements(portal.IRealm)

    def __init__(self):
        # I don't know if i'm supposed to keep static stuff here
        self.env = core.honeypot.HoneyPotEnvironment()

    def requestAvatar(self, avatarId, mind, *interfaces):
        if conchinterfaces.IConchUser in interfaces:
            return interfaces[0], \
                HoneyPotAvatar(avatarId, self.env), lambda: None
        else:
            raise Exception, "No supported interfaces found."

class HoneyPotTransport(transport.SSHServerTransport):

    hadVersion = False

    def connectionMade(self):
        print 'New connection: %s:%s (%s:%s) [session: %d]' % \
            (self.transport.getPeer().host, self.transport.getPeer().port,
            self.transport.getHost().host, self.transport.getHost().port,
            self.transport.sessionno)
        self.interactors = []
        self.logintime = time.time()
        self.ttylog_open = False
        transport.SSHServerTransport.connectionMade(self)

    def sendKexInit(self):
        # Don't send key exchange prematurely
        if not self.gotVersion:
            return
        transport.SSHServerTransport.sendKexInit(self)

    def dataReceived(self, data):
        transport.SSHServerTransport.dataReceived(self, data)
        # later versions seem to call sendKexInit again on their own
        if twisted.version.major < 11 and \
                not self.hadVersion and self.gotVersion:
            self.sendKexInit()
            self.hadVersion = True

    def ssh_KEXINIT(self, packet):
        print 'Remote SSH version: %s' % (self.otherVersionString,)
        return transport.SSHServerTransport.ssh_KEXINIT(self, packet)

    def lastlogExit(self):
        starttime = time.strftime('%a %b %d %H:%M',
            time.localtime(self.logintime))
        endtime = time.strftime('%H:%M',
            time.localtime(time.time()))
        duration = utils.durationHuman(time.time() - self.logintime)
        clientIP = self.transport.getPeer().host
        utils.addToLastlog('root\tpts/0\t%s\t%s - %s (%s)' % \
            (clientIP, starttime, endtime, duration))

    # this seems to be the only reliable place of catching lost connection
    def connectionLost(self, reason):
        for i in self.interactors:
            i.sessionClosed()
        if self.transport.sessionno in self.factory.sessions:
            del self.factory.sessions[self.transport.sessionno]
        self.lastlogExit()
        if self.ttylog_open:
            ttylog.ttylog_close(self.ttylog_file, time.time())
            self.ttylog_open = False
        transport.SSHServerTransport.connectionLost(self, reason)

    def sendDisconnect(self, reason, desc):
        """
        Workaround for the "bad packet length" error message.

        @param reason: the reason for the disconnect.  Should be one of the
                       DISCONNECT_* values.
        @type reason: C{int}
        @param desc: a descrption of the reason for the disconnection.
        @type desc: C{str}
        """
        if not 'bad packet length' in desc:
            # With python >= 3 we can use super?
            transport.SSHServerTransport.sendDisconnect(self, reason, desc)
        else:
            self.transport.write('Protocol mismatch.\n')
            log.msg('Disconnecting with error, code %s\nreason: %s' % \
                (reason, desc))
            self.transport.loseConnection()

class HoneyPotSSHSession(session.SSHSession):
    def request_env(self, data):
        print 'request_env: %s' % (repr(data))

class HoneyPotAvatar(avatar.ConchUser):
    implements(conchinterfaces.ISession)

    def __init__(self, username, env):
        avatar.ConchUser.__init__(self)
        self.username = username
        self.env = env
        self.channelLookup.update({'session': HoneyPotSSHSession})

        userdb = core.auth.UserDB()
        self.uid = self.gid = userdb.getUID(self.username)

        if not self.uid:
            self.home = '/root'
        else:
            self.home = '/home/' + username

    def openShell(self, protocol):
        serverProtocol = core.protocol.LoggingServerProtocol(
            core.protocol.HoneyPotInteractiveProtocol, self, self.env)
        serverProtocol.makeConnection(protocol)
        protocol.makeConnection(session.wrapProtocol(serverProtocol))

    def getPty(self, terminal, windowSize, attrs):
        print 'Terminal size: %s %s' % windowSize[0:2]
        self.windowSize = windowSize
        return None

    def execCommand(self, protocol, cmd):
        cfg = config()
        if not cfg.has_option('honeypot', 'exec_enabled') or \
                cfg.get('honeypot', 'exec_enabled').lower() not in \
                    ('yes', 'true', 'on'):
            print 'Exec disabled. Not executing command: "%s"' % cmd
            raise core.exceptions.NotEnabledException, \
                'exec_enabled not enabled in configuration file!'
            return

        print 'exec command: "%s"' % cmd
        serverProtocol = kippo.core.protocol.LoggingServerProtocol(
            kippo.core.protocol.HoneyPotExecProtocol, self, self.env, cmd)
        serverProtocol.makeConnection(protocol)
        protocol.makeConnection(session.wrapProtocol(serverProtocol))

    def closed(self):
        pass

    def eofReceived(self):
        pass

    def windowChanged(self, windowSize):
        self.windowSize = windowSize

def getRSAKeys():
    cfg = config()
    public_key = cfg.get('honeypot', 'rsa_public_key')
    private_key = cfg.get('honeypot', 'rsa_private_key')
    if not (os.path.exists(public_key) and os.path.exists(private_key)):
        print "Generating new RSA keypair..."
        from Crypto.PublicKey import RSA
        from twisted.python import randbytes
        KEY_LENGTH = 2048
        rsaKey = RSA.generate(KEY_LENGTH, randbytes.secureRandom)
        publicKeyString = keys.Key(rsaKey).public().toString('openssh')
        privateKeyString = keys.Key(rsaKey).toString('openssh')
        with file(public_key, 'w+b') as f:
            f.write(publicKeyString)
        with file(private_key, 'w+b') as f:
            f.write(privateKeyString)
        print "Done."
    else:
        with file(public_key) as f:
            publicKeyString = f.read()
        with file(private_key) as f:
            privateKeyString = f.read()
    return publicKeyString, privateKeyString

def getDSAKeys():
    cfg = config()
    public_key = cfg.get('honeypot', 'dsa_public_key')
    private_key = cfg.get('honeypot', 'dsa_private_key')
    if not (os.path.exists(public_key) and os.path.exists(private_key)):
        print "Generating new DSA keypair..."
        from Crypto.PublicKey import DSA
        from twisted.python import randbytes
        KEY_LENGTH = 1024
        dsaKey = DSA.generate(KEY_LENGTH, randbytes.secureRandom)
        publicKeyString = keys.Key(dsaKey).public().toString('openssh')
        privateKeyString = keys.Key(dsaKey).toString('openssh')
        with file(public_key, 'w+b') as f:
            f.write(publicKeyString)
        with file(private_key, 'w+b') as f:
            f.write(privateKeyString)
        print "Done."
    else:
        with file(public_key) as f:
            publicKeyString = f.read()
        with file(private_key) as f:
            privateKeyString = f.read()
    return publicKeyString, privateKeyString

# vim: set et sw=4 et: