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Diffstat (limited to 'src/leap/crypto/srpauth.py')
| -rw-r--r-- | src/leap/crypto/srpauth.py | 606 |
1 files changed, 606 insertions, 0 deletions
diff --git a/src/leap/crypto/srpauth.py b/src/leap/crypto/srpauth.py new file mode 100644 index 00000000..fc0533fc --- /dev/null +++ b/src/leap/crypto/srpauth.py @@ -0,0 +1,606 @@ +# -*- coding: utf-8 -*- +# srpauth.py +# Copyright (C) 2013 LEAP +# +# 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 3 of the License, 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. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see <http://www.gnu.org/licenses/>. + +import binascii +import logging + +import requests +import srp +import json + +#this error is raised from requests +from simplejson.decoder import JSONDecodeError +from functools import partial + +from PySide import QtCore +from twisted.internet import threads + +from leap.common.check import leap_assert +from leap.util.constants import REQUEST_TIMEOUT +from leap.util import request_helpers as reqhelper +from leap.common.events import signal as events_signal +from leap.common.events import events_pb2 as proto + +logger = logging.getLogger(__name__) + + +class SRPAuthenticationError(Exception): + """ + Exception raised for authentication errors + """ + pass + + +class SRPAuthConnectionError(SRPAuthenticationError): + """ + Exception raised when there's a connection error + """ + pass + + +class SRPAuthUnknownUser(SRPAuthenticationError): + """ + Exception raised when trying to authenticate an unknown user + """ + pass + + +class SRPAuthBadStatusCode(SRPAuthenticationError): + """ + Exception raised when we received an unknown bad status code + """ + pass + + +class SRPAuthNoSalt(SRPAuthenticationError): + """ + Exception raised when we don't receive the salt param at a + specific point in the auth process + """ + pass + + +class SRPAuthNoB(SRPAuthenticationError): + """ + Exception raised when we don't receive the B param at a specific + point in the auth process + """ + pass + + +class SRPAuthBadDataFromServer(SRPAuthenticationError): + """ + Generic exception when we receive bad data from the server. + """ + pass + + +class SRPAuthJSONDecodeError(SRPAuthenticationError): + """ + Exception raised when there's a problem decoding the JSON content + parsed as received from th e server. + """ + pass + + +class SRPAuthBadPassword(SRPAuthenticationError): + """ + Exception raised when the user provided a bad password to auth. + """ + pass + + +class SRPAuthVerificationFailed(SRPAuthenticationError): + """ + Exception raised when we can't verify the SRP data received from + the server. + """ + pass + + +class SRPAuthNoSessionId(SRPAuthenticationError): + """ + Exception raised when we don't receive a session id from the + server. + """ + pass + + +class SRPAuth(QtCore.QObject): + """ + SRPAuth singleton + """ + + class __impl(QtCore.QObject): + """ + Implementation of the SRPAuth interface + """ + + LOGIN_KEY = "login" + A_KEY = "A" + CLIENT_AUTH_KEY = "client_auth" + SESSION_ID_KEY = "_session_id" + + def __init__(self, provider_config): + """ + Constructor for SRPAuth implementation + + :param server: Server to which we will authenticate + :type server: str + """ + QtCore.QObject.__init__(self) + + leap_assert(provider_config, + "We need a provider config to authenticate") + + self._provider_config = provider_config + + # **************************************************** # + # Dependency injection helpers, override this for more + # granular testing + self._fetcher = requests + self._srp = srp + self._hashfun = self._srp.SHA256 + self._ng = self._srp.NG_1024 + # **************************************************** # + + self._session = self._fetcher.session() + self._session_id = None + self._session_id_lock = QtCore.QMutex() + self._uid = None + self._uid_lock = QtCore.QMutex() + self._token = None + self._token_lock = QtCore.QMutex() + + self._srp_user = None + self._srp_a = None + + def _safe_unhexlify(self, val): + """ + Rounds the val to a multiple of 2 and returns the + unhexlified value + + :param val: hexlified value + :type val: str + + :rtype: binary hex data + :return: unhexlified val + """ + return binascii.unhexlify(val) \ + if (len(val) % 2 == 0) else binascii.unhexlify('0' + val) + + def _authentication_preprocessing(self, username, password): + """ + Generates the SRP.User to get the A SRP parameter + + :param username: username to login + :type username: str + :param password: password for the username + :type password: str + """ + logger.debug("Authentication preprocessing...") + self._srp_user = self._srp.User(username, + password, + self._hashfun, + self._ng) + _, A = self._srp_user.start_authentication() + + self._srp_a = A + + def _start_authentication(self, _, username): + """ + Sends the first request for authentication to retrieve the + salt and B parameter + + Might raise all SRPAuthenticationError based: + SRPAuthenticationError + SRPAuthConnectionError + SRPAuthUnknownUser + SRPAuthBadStatusCode + SRPAuthNoSalt + SRPAuthNoB + + :param _: IGNORED, output from the previous callback (None) + :type _: IGNORED + :param username: username to login + :type username: str + + :return: salt and B parameters + :rtype: tuple + """ + logger.debug("Starting authentication process...") + try: + auth_data = { + self.LOGIN_KEY: username, + self.A_KEY: binascii.hexlify(self._srp_a) + } + sessions_url = "%s/%s/%s/" % \ + (self._provider_config.get_api_uri(), + self._provider_config.get_api_version(), + "sessions") + init_session = self._session.post(sessions_url, + data=auth_data, + verify=self._provider_config. + get_ca_cert_path(), + timeout=REQUEST_TIMEOUT) + # Clean up A value, we don't need it anymore + self._srp_a = None + except requests.exceptions.ConnectionError as e: + logger.error("No connection made (salt): %r" % + (e,)) + raise SRPAuthConnectionError("Could not establish a " + "connection") + except Exception as e: + logger.error("Unknown error: %r" % (e,)) + raise SRPAuthenticationError("Unknown error: %r" % + (e,)) + + content, mtime = reqhelper.get_content(init_session) + + if init_session.status_code not in (200,): + logger.error("No valid response (salt): " + "Status code = %r. Content: %r" % + (init_session.status_code, content)) + if init_session.status_code == 422: + raise SRPAuthUnknownUser(self.tr("Unknown user")) + + raise SRPAuthBadStatusCode(self.tr("There was a problem with" + " authentication")) + + json_content = json.loads(content) + salt = json_content.get("salt", None) + B = json_content.get("B", None) + + if salt is None: + logger.error("No salt parameter sent") + raise SRPAuthNoSalt(self.tr("The server did not send " + "the salt parameter")) + if B is None: + logger.error("No B parameter sent") + raise SRPAuthNoB(self.tr("The server did not send " + "the B parameter")) + + return salt, B + + def _process_challenge(self, salt_B, username): + """ + Given the salt and B processes the auth challenge and + generates the M2 parameter + + Might raise SRPAuthenticationError based: + SRPAuthenticationError + SRPAuthBadDataFromServer + SRPAuthConnectionError + SRPAuthJSONDecodeError + SRPAuthBadPassword + + :param salt_B: salt and B parameters for the username + :type salt_B: tuple + :param username: username for this session + :type username: str + + :return: the M2 SRP parameter + :rtype: str + """ + logger.debug("Processing challenge...") + try: + salt, B = salt_B + unhex_salt = self._safe_unhexlify(salt) + unhex_B = self._safe_unhexlify(B) + except (TypeError, ValueError) as e: + logger.error("Bad data from server: %r" % (e,)) + raise SRPAuthBadDataFromServer( + self.tr("The data sent from the server had errors")) + M = self._srp_user.process_challenge(unhex_salt, unhex_B) + + auth_url = "%s/%s/%s/%s" % (self._provider_config.get_api_uri(), + self._provider_config. + get_api_version(), + "sessions", + username) + + auth_data = { + self.CLIENT_AUTH_KEY: binascii.hexlify(M) + } + + try: + auth_result = self._session.put(auth_url, + data=auth_data, + verify=self._provider_config. + get_ca_cert_path(), + timeout=REQUEST_TIMEOUT) + except requests.exceptions.ConnectionError as e: + logger.error("No connection made (HAMK): %r" % (e,)) + raise SRPAuthConnectionError(self.tr("Could not connect to " + "the server")) + + try: + content, mtime = reqhelper.get_content(auth_result) + except JSONDecodeError: + raise SRPAuthJSONDecodeError("Bad JSON content in auth result") + + if auth_result.status_code == 422: + error = "" + try: + error = json.loads(content).get("errors", "") + except ValueError: + logger.error("Problem parsing the received response: %s" + % (content,)) + except AttributeError: + logger.error("Expecting a dict but something else was " + "received: %s", (content,)) + logger.error("[%s] Wrong password (HAMK): [%s]" % + (auth_result.status_code, error)) + raise SRPAuthBadPassword(self.tr("Wrong password")) + + if auth_result.status_code not in (200,): + logger.error("No valid response (HAMK): " + "Status code = %s. Content = %r" % + (auth_result.status_code, content)) + raise SRPAuthBadStatusCode(self.tr("Unknown error (%s)") % + (auth_result.status_code,)) + + return json.loads(content) + + def _extract_data(self, json_content): + """ + Extracts the necessary parameters from json_content (M2, + id, token) + + Might raise SRPAuthenticationError based: + SRPBadDataFromServer + + :param json_content: Data received from the server + :type json_content: dict + """ + try: + M2 = json_content.get("M2", None) + uid = json_content.get("id", None) + token = json_content.get("token", None) + except Exception as e: + logger.error(e) + raise SRPAuthBadDataFromServer("Something went wrong with the " + "login") + + self.set_uid(uid) + self.set_token(token) + + if M2 is None or self.get_uid() is None: + logger.error("Something went wrong. Content = %r" % + (json_content,)) + raise SRPAuthBadDataFromServer(self.tr("Problem getting data " + "from server")) + + events_signal( + proto.CLIENT_UID, content=uid, + reqcbk=lambda req, res: None) # make the rpc call async + + return M2 + + def _verify_session(self, M2): + """ + Verifies the session based on the M2 parameter. If the + verification succeeds, it sets the session_id for this + session + + Might raise SRPAuthenticationError based: + SRPAuthBadDataFromServer + SRPAuthVerificationFailed + + :param M2: M2 SRP parameter + :type M2: str + """ + logger.debug("Verifying session...") + try: + unhex_M2 = self._safe_unhexlify(M2) + except TypeError: + logger.error("Bad data from server (HAWK)") + raise SRPAuthBadDataFromServer(self.tr("Bad data from server")) + + self._srp_user.verify_session(unhex_M2) + + if not self._srp_user.authenticated(): + logger.error("Auth verification failed") + raise SRPAuthVerificationFailed(self.tr("Auth verification " + "failed")) + logger.debug("Session verified.") + + session_id = self._session.cookies.get(self.SESSION_ID_KEY, None) + if not session_id: + logger.error("Bad cookie from server (missing _session_id)") + raise SRPAuthNoSessionId(self.tr("Session cookie " + "verification " + "failed")) + + events_signal( + proto.CLIENT_SESSION_ID, content=session_id, + reqcbk=lambda req, res: None) # make the rpc call async + + self.set_session_id(session_id) + + def _threader(self, cb, res, *args, **kwargs): + return threads.deferToThread(cb, res, *args, **kwargs) + + def authenticate(self, username, password): + """ + Executes the whole authentication process for a user + + Might raise SRPAuthenticationError + + :param username: username for this session + :type username: str + :param password: password for this user + :type password: str + + :returns: A defer on a different thread + :rtype: twisted.internet.defer.Deferred + """ + leap_assert(self.get_session_id() is None, "Already logged in") + + d = threads.deferToThread(self._authentication_preprocessing, + username=username, + password=password) + + d.addCallback( + partial(self._threader, + self._start_authentication), + username=username) + d.addCallback( + partial(self._threader, + self._process_challenge), + username=username) + d.addCallback( + partial(self._threader, + self._extract_data)) + d.addCallback(partial(self._threader, + self._verify_session)) + + return d + + def logout(self): + """ + Logs out the current session. + Expects a session_id to exists, might raise AssertionError + """ + logger.debug("Starting logout...") + + leap_assert(self.get_session_id(), + "Cannot logout an unexisting session") + + logout_url = "%s/%s/%s/" % (self._provider_config.get_api_uri(), + self._provider_config. + get_api_version(), + "sessions") + try: + self._session.delete(logout_url, + data=self.get_session_id(), + verify=self._provider_config. + get_ca_cert_path(), + timeout=REQUEST_TIMEOUT) + except Exception as e: + logger.warning("Something went wrong with the logout: %r" % + (e,)) + + self.set_session_id(None) + self.set_uid(None) + # Also reset the session + self._session = self._fetcher.session() + logger.debug("Successfully logged out.") + + def set_session_id(self, session_id): + QtCore.QMutexLocker(self._session_id_lock) + self._session_id = session_id + + def get_session_id(self): + QtCore.QMutexLocker(self._session_id_lock) + return self._session_id + + def set_uid(self, uid): + QtCore.QMutexLocker(self._uid_lock) + self._uid = uid + + def get_uid(self): + QtCore.QMutexLocker(self._uid_lock) + return self._uid + + def set_token(self, token): + QtCore.QMutexLocker(self._token_lock) + self._token = token + + def get_token(self): + QtCore.QMutexLocker(self._token_lock) + return self._token + + __instance = None + + authentication_finished = QtCore.Signal(bool, str) + logout_finished = QtCore.Signal(bool, str) + + def __init__(self, provider_config): + """ + Creates a singleton instance if needed + """ + QtCore.QObject.__init__(self) + + # Check whether we already have an instance + if SRPAuth.__instance is None: + # Create and remember instance + SRPAuth.__instance = SRPAuth.__impl(provider_config) + + # Store instance reference as the only member in the handle + self.__dict__['_SRPAuth__instance'] = SRPAuth.__instance + + def authenticate(self, username, password): + """ + Executes the whole authentication process for a user + + Might raise SRPAuthenticationError based + + :param username: username for this session + :type username: str + :param password: password for this user + :type password: str + """ + + d = self.__instance.authenticate(username, password) + d.addCallback(self._gui_notify) + d.addErrback(self._errback) + return d + + def _gui_notify(self, _): + """ + Callback that notifies the UI with the proper signal. + + :param _: IGNORED, output from the previous callback (None) + :type _: IGNORED + """ + logger.debug("Successful login!") + self.authentication_finished.emit(True, self.tr("Succeeded")) + + def _errback(self, failure): + """ + General errback for the whole login process. Will notify the + UI with the proper signal. + + :param failure: Failure object captured from a callback. + :type failure: twisted.python.failure.Failure + """ + logger.error("Error logging in %s" % (failure,)) + self.authentication_finished.emit(False, "%s" % (failure.value,)) + failure.trap(Exception) + + def get_session_id(self): + return self.__instance.get_session_id() + + def get_uid(self): + return self.__instance.get_uid() + + def get_token(self): + return self.__instance.get_token() + + def logout(self): + """ + Logs out the current session. + Expects a session_id to exists, might raise AssertionError + """ + try: + self.__instance.logout() + self.logout_finished.emit(True, self.tr("Succeeded")) + return True + except Exception as e: + self.logout_finished.emit(False, "%s" % (e,)) + return False |