auth.py

##   auth.py
##
##   Copyright (C) 2003-2005 Alexey "Snake" Nezhdanov
##
##   This program is free software; you can redistribute it and/or modify
##   it under the terms of the GNU General Public License as published by
##   the Free Software Foundation; either version 2, or (at your option)
##   any later version.
##
##   This program is distributed in the hope that it will be useful,
##   but WITHOUT ANY WARRANTY; without even the implied warranty of
##   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
##   GNU General Public License for more details.

# $Id$

"""
Provides library with all Non-SASL and SASL authentication mechanisms.
Can be used both for client and transport authentication.
"""

from .protocol import *
from .client import PlugIn
import base64,random,re
from . import dispatcher
from hashlib import md5,sha1
from six import ensure_str,ensure_binary

CHARSET_ENCODING='utf-8'

def HH(some):
    return md5(ensure_binary(some, CHARSET_ENCODING)).hexdigest()
def H(some):
    return md5(ensure_binary(some, CHARSET_ENCODING)).digest()
def C(some):
    some = [ensure_binary(x, CHARSET_ENCODING) for x in some]
    return b':'.join(some)

def HHSHA1(some):
    return sha1(ensure_binary(some, CHARSET_ENCODING)).hexdigest()
def B64(some):
    return ensure_str(base64.b64encode(ensure_binary(some,CHARSET_ENCODING)),CHARSET_ENCODING)

class NonSASL(PlugIn):
    """ Implements old Non-SASL (XEP-0078) authentication used in jabberd1.4 and transport authentication."""
    def __init__(self,user,password,resource):
        """ Caches username, password and resource for auth. """
        PlugIn.__init__(self)
        self.DBG_LINE='gen_auth'
        self.user=user
        self.password=password
        self.resource=resource

    def plugin(self,owner):
        """ Determine the best auth method (digest/0k/plain) and use it for auth.
            Returns used method name on success. Used internally. """
        if not self.resource: return self.authComponent(owner)
        self.DEBUG('Querying server about possible auth methods','start')
        resp=owner.Dispatcher.SendAndWaitForResponse(Iq('get',NS_AUTH,payload=[Node('username',payload=[self.user])]))
        if not isResultNode(resp):
            self.DEBUG('No result node arrived! Aborting...','error')
            return
        iq=Iq(typ='set',node=resp)
        query=iq.getTag('query')
        query.setTagData('username',self.user)
        query.setTagData('resource',self.resource)

        if query.getTag('digest'):
            self.DEBUG("Performing digest authentication",'ok')
            query.setTagData('digest',HHSHA1(owner.Dispatcher.Stream._document_attrs['id']+self.password))
            if query.getTag('password'): query.delChild('password')
            method='digest'
        elif query.getTag('token'):
            token=query.getTagData('token')
            seq=query.getTagData('sequence')
            self.DEBUG("Performing zero-k authentication",'ok')
            hash = HHSHA1(HHSHA1(self.password)+token)
            for foo in range(int(seq)): hash = HHSHA1(hash)
            query.setTagData('hash',hash)
            method='0k'
        else:
            self.DEBUG("Sequre methods unsupported, performing plain text authentication",'warn')
            query.setTagData('password',self.password)
            method='plain'
        resp=owner.Dispatcher.SendAndWaitForResponse(iq)
        if isResultNode(resp):
            self.DEBUG('Sucessfully authenticated with remove host.','ok')
            owner.User=self.user
            owner.Resource=self.resource
            owner._registered_name=owner.User+'@'+owner.Server+'/'+owner.Resource
            return method
        self.DEBUG('Authentication failed!','error')

    def authComponent(self,owner):
        """ Authenticate component. Send handshake stanza and wait for result. Returns "ok" on success. """
        self.handshake=0
        owner.send(Node(NS_COMPONENT_ACCEPT+' handshake',payload=[HHSHA1(owner.Dispatcher.Stream._document_attrs['id']+self.password)]))
        owner.RegisterHandler('handshake',self.handshakeHandler,xmlns=NS_COMPONENT_ACCEPT)
        while not self.handshake:
            self.DEBUG("waiting on handshake",'notify')
            owner.Process(1)
        owner._registered_name=self.user
        if self.handshake+1: return 'ok'

    def handshakeHandler(self,disp,stanza):
        """ Handler for registering in dispatcher for accepting transport authentication. """
        if stanza.getName()=='handshake': self.handshake=1
        else: self.handshake=-1

class SASL(PlugIn):
    """ Implements SASL authentication. """
    def __init__(self,username,password):
        PlugIn.__init__(self)
        self.username=username
        self.password=password

    def plugin(self,owner):
        if 'version' not in self._owner.Dispatcher.Stream._document_attrs: self.startsasl='not-supported'
        elif self._owner.Dispatcher.Stream.features:
            try: self.FeaturesHandler(self._owner.Dispatcher,self._owner.Dispatcher.Stream.features)
            except NodeProcessed: pass
        else: self.startsasl=None

    def auth(self):
        """ Start authentication. Result can be obtained via "SASL.startsasl" attribute and will be
            either "success" or "failure". Note that successfull auth will take at least
            two Dispatcher.Process() calls. """
        if self.startsasl: pass
        elif self._owner.Dispatcher.Stream.features:
            try: self.FeaturesHandler(self._owner.Dispatcher,self._owner.Dispatcher.Stream.features)
            except NodeProcessed: pass
        else: self._owner.RegisterHandler('features',self.FeaturesHandler,xmlns=NS_STREAMS)

    def plugout(self):
        """ Remove SASL handlers from owner's dispatcher. Used internally. """
        if 'features' in self._owner.__dict__: self._owner.UnregisterHandler('features',self.FeaturesHandler,xmlns=NS_STREAMS)
        if 'challenge' in self._owner.__dict__: self._owner.UnregisterHandler('challenge',self.SASLHandler,xmlns=NS_SASL)
        if 'failure' in self._owner.__dict__: self._owner.UnregisterHandler('failure',self.SASLHandler,xmlns=NS_SASL)
        if 'success' in self._owner.__dict__: self._owner.UnregisterHandler('success',self.SASLHandler,xmlns=NS_SASL)

    def FeaturesHandler(self,conn,feats):
        """ Used to determine if server supports SASL auth. Used internally. """
        if not feats.getTag('mechanisms',namespace=NS_SASL):
            self.startsasl='not-supported'
            self.DEBUG('SASL not supported by server','error')
            return
        mecs=[]
        for mec in feats.getTag('mechanisms',namespace=NS_SASL).getTags('mechanism'):
            mecs.append(mec.getData())
        self._owner.RegisterHandler('challenge',self.SASLHandler,xmlns=NS_SASL)
        self._owner.RegisterHandler('failure',self.SASLHandler,xmlns=NS_SASL)
        self._owner.RegisterHandler('success',self.SASLHandler,xmlns=NS_SASL)
        if "ANONYMOUS" in mecs and self.username == None:
            node=Node('auth',attrs={'xmlns':NS_SASL,'mechanism':'ANONYMOUS'})
        elif "DIGEST-MD5" in mecs:
            node=Node('auth',attrs={'xmlns':NS_SASL,'mechanism':'DIGEST-MD5'})
        elif "PLAIN" in mecs:
            sasl_data='%s\x00%s\x00%s'%(self.username+'@'+self._owner.Server,self.username,self.password)
            node=Node('auth',attrs={'xmlns':NS_SASL,'mechanism':'PLAIN'},payload=[B64(sasl_data)])
        else:
            self.startsasl='failure'
            self.DEBUG('I can only use DIGEST-MD5 and PLAIN mecanisms.','error')
            return
        self.startsasl='in-process'
        self._owner.send(node.__str__())
        raise NodeProcessed

    def SASLHandler(self,conn,challenge):
        """ Perform next SASL auth step. Used internally. """
        if challenge.getNamespace()!=NS_SASL: return
        if challenge.getName()=='failure':
            self.startsasl='failure'
            try: reason=challenge.getChildren()[0]
            except: reason=challenge
            self.DEBUG('Failed SASL authentification: %s'%reason,'error')
            raise NodeProcessed
        elif challenge.getName()=='success':
            self.startsasl='success'
            self.DEBUG('Successfully authenticated with remote server.','ok')
            handlers=self._owner.Dispatcher.dumpHandlers()
            self._owner.Dispatcher.PlugOut()
            dispatcher.Dispatcher().PlugIn(self._owner)
            self._owner.Dispatcher.restoreHandlers(handlers)
            self._owner.User=self.username
            raise NodeProcessed
########################################3333
        incoming_data=challenge.getData()
        chal={}
        data=base64.b64decode(incoming_data)
        data=ensure_str(data,CHARSET_ENCODING)
        self.DEBUG('Got challenge: '+data,'ok')
        for pair in re.findall('(\w+\s*=\s*(?:(?:"[^"]+")|(?:[^,]+)))',data):
            key,value=[x.strip() for x in pair.split('=', 1)]
            if value[:1]=='"' and value[-1:]=='"': value=value[1:-1]
            chal[key]=value
        if 'qop' in chal and 'auth' in [x.strip() for x in chal['qop'].split(',')]:
            resp={}
            resp['username']=self.username
            resp['realm']=self._owner.Server
            resp['nonce']=chal['nonce']
            cnonce=''
            for i in range(7):
                cnonce+=hex(int(random.random()*65536*4096))[2:]
            resp['cnonce']=cnonce
            resp['nc']=('00000001')
            resp['qop']='auth'
            resp['digest-uri']='xmpp/'+self._owner.Server
            A1=C([H(C([resp['username'],resp['realm'],self.password])),resp['nonce'],resp['cnonce']])
            A2=C(['AUTHENTICATE',resp['digest-uri']])
            response= HH(C([HH(A1),resp['nonce'],resp['nc'],resp['cnonce'],resp['qop'],HH(A2)]))
            resp['response']=response
            resp['charset']=CHARSET_ENCODING
            sasl_data=''
            for key in ['charset','username','realm','nonce','nc','cnonce','digest-uri','response','qop']:
                if key in ['nc','qop','response','charset']: sasl_data+="%s=%s,"%(key,resp[key])
                else: sasl_data+='%s="%s",'%(key,resp[key])
########################################3333
            node=Node('response',attrs={'xmlns':NS_SASL},payload=[B64(sasl_data[:-1])])
            self._owner.send(node.__str__())
        elif 'rspauth' in chal: self._owner.send(Node('response',attrs={'xmlns':NS_SASL}).__str__())
        else:
            self.startsasl='failure'
            self.DEBUG('Failed SASL authentification: unknown challenge','error')
        raise NodeProcessed

class Bind(PlugIn):
    """ Bind some JID to the current connection to allow router know of our location."""
    def __init__(self):
        PlugIn.__init__(self)
        self.DBG_LINE='bind'
        self.bound=None

    def plugin(self,owner):
        """ Start resource binding, if allowed at this time. Used internally. """
        if self._owner.Dispatcher.Stream.features:
            try: self.FeaturesHandler(self._owner.Dispatcher,self._owner.Dispatcher.Stream.features)
            except NodeProcessed: pass
        else: self._owner.RegisterHandler('features',self.FeaturesHandler,xmlns=NS_STREAMS)

    def plugout(self):
        """ Remove Bind handler from owner's dispatcher. Used internally. """
        self._owner.UnregisterHandler('features',self.FeaturesHandler,xmlns=NS_STREAMS)

    def FeaturesHandler(self,conn,feats):
        """ Determine if server supports resource binding and set some internal attributes accordingly. """
        if not feats.getTag('bind',namespace=NS_BIND):
            self.bound='failure'
            self.DEBUG('Server does not requested binding.','error')
            return
        if feats.getTag('session',namespace=NS_SESSION): self.session=1
        else: self.session=-1
        self.bound=[]

    def Bind(self,resource=None):
        """ Perform binding. Use provided resource name or random (if not provided). """
        while self.bound is None and self._owner.Process(1): pass
        if resource: resource=[Node('resource',payload=[resource])]
        else: resource=[]
        resp=self._owner.SendAndWaitForResponse(Protocol('iq',typ='set',payload=[Node('bind',attrs={'xmlns':NS_BIND},payload=resource)]))
        if isResultNode(resp):
            self.bound.append(resp.getTag('bind').getTagData('jid'))
            self.DEBUG('Successfully bound %s.'%self.bound[-1],'ok')
            jid=JID(resp.getTag('bind').getTagData('jid'))
            self._owner.User=jid.getNode()
            self._owner.Resource=jid.getResource()
            resp=self._owner.SendAndWaitForResponse(Protocol('iq',typ='set',payload=[Node('session',attrs={'xmlns':NS_SESSION})]))
            if isResultNode(resp):
                self.DEBUG('Successfully opened session.','ok')
                self.session=1
                return 'ok'
            else:
                self.DEBUG('Session open failed.','error')
                self.session=0
        elif resp: self.DEBUG('Binding failed: %s.'%resp.getTag('error'),'error')
        else:
            self.DEBUG('Binding failed: timeout expired.','error')
            return ''

class ComponentBind(PlugIn):
    """ ComponentBind some JID to the current connection to allow router know of our location."""
    def __init__(self, sasl):
        PlugIn.__init__(self)
        self.DBG_LINE='bind'
        self.bound=None
        self.needsUnregister=None
        self.sasl = sasl

    def plugin(self,owner):
        """ Start resource binding, if allowed at this time. Used internally. """
        if not self.sasl:
            self.bound=[]
            return
        if self._owner.Dispatcher.Stream.features:
            try: self.FeaturesHandler(self._owner.Dispatcher,self._owner.Dispatcher.Stream.features)
            except NodeProcessed: pass
        else:
            self._owner.RegisterHandler('features',self.FeaturesHandler,xmlns=NS_STREAMS)
            self.needsUnregister=1

    def plugout(self):
        """ Remove ComponentBind handler from owner's dispatcher. Used internally. """
        if self.needsUnregister:
            self._owner.UnregisterHandler('features',self.FeaturesHandler,xmlns=NS_STREAMS)

    def FeaturesHandler(self,conn,feats):
        """ Determine if server supports resource binding and set some internal attributes accordingly. """
        if not feats.getTag('bind',namespace=NS_BIND):
            self.bound='failure'
            self.DEBUG('Server does not requested binding.','error')
            return
        if feats.getTag('session',namespace=NS_SESSION): self.session=1
        else: self.session=-1
        self.bound=[]

    def Bind(self,domain=None):
        """ Perform binding. Use provided domain name (if not provided). """
        while self.bound is None and self._owner.Process(1): pass
        if self.sasl:
            xmlns = NS_COMPONENT_1
        else:
            xmlns = None
        self.bindresponse = None
        ttl = dispatcher.DefaultTimeout
        self._owner.RegisterHandler('bind',self.BindHandler,xmlns=xmlns)
        self._owner.send(Protocol('bind',attrs={'name':domain},xmlns=NS_COMPONENT_1))
        while self.bindresponse is None and self._owner.Process(1) and ttl > 0: ttl-=1
        self._owner.UnregisterHandler('bind',self.BindHandler,xmlns=xmlns)
        resp=self.bindresponse
        if resp and resp.getAttr('error'):
            self.DEBUG('Binding failed: %s.'%resp.getAttr('error'),'error')
        elif resp:
            self.DEBUG('Successfully bound.','ok')
            return 'ok'
        else:
            self.DEBUG('Binding failed: timeout expired.','error')
            return ''

    def BindHandler(self,conn,bind):
        self.bindresponse = bind
        pass