# -*- coding: utf-8 -*- # fetch.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 . """ Incoming mail fetcher. """ import logging import json import ssl import threading import time from email.parser import Parser from twisted.python import log from twisted.internet.task import LoopingCall from twisted.internet.threads import deferToThread from leap.common import events as leap_events from leap.common.check import leap_assert, leap_assert_type from leap.soledad.client import Soledad from leap.soledad.common.crypto import ENC_SCHEME_KEY, ENC_JSON_KEY from leap.common.events.events_pb2 import IMAP_FETCHED_INCOMING from leap.common.events.events_pb2 import IMAP_MSG_PROCESSING from leap.common.events.events_pb2 import IMAP_MSG_DECRYPTED from leap.common.events.events_pb2 import IMAP_MSG_SAVED_LOCALLY from leap.common.events.events_pb2 import IMAP_MSG_DELETED_INCOMING from leap.common.events.events_pb2 import IMAP_UNREAD_MAIL logger = logging.getLogger(__name__) class MalformedMessage(Exception): """ Raised when a given message is not well formed. """ pass class LeapIncomingMail(object): """ Fetches mail from the incoming queue. """ RECENT_FLAG = "\\Recent" INCOMING_KEY = "incoming" CONTENT_KEY = "content" fetching_lock = threading.Lock() def __init__(self, keymanager, soledad, imap_account, check_period): """ Initialize LeapIMAP. :param keymanager: a keymanager instance :type keymanager: keymanager.KeyManager :param soledad: a soledad instance :type soledad: Soledad :param imap_account: the account to fetch periodically :type imap_account: SoledadBackedAccount :param check_period: the period to fetch new mail, in seconds. :type check_period: int """ leap_assert(keymanager, "need a keymanager to initialize") leap_assert_type(soledad, Soledad) leap_assert(check_period, "need a period to check incoming mail") leap_assert_type(check_period, int) self._keymanager = keymanager self._soledad = soledad self.imapAccount = imap_account self._inbox = self.imapAccount.getMailbox('inbox') self._pkey = self._keymanager.get_all_keys_in_local_db( private=True).pop() self._loop = None self._check_period = check_period self._create_soledad_indexes() def _create_soledad_indexes(self): """ Create needed indexes on soledad. """ self._soledad.create_index("just-mail", "incoming") # # Public API: fetch, start_loop, stop. # def fetch(self): """ Fetch incoming mail, to be called periodically. Calls a deferred that will execute the fetch callback in a separate thread """ if not self.fetching_lock.locked(): d = deferToThread(self._sync_soledad) d.addCallbacks(self._signal_fetch_to_ui, self._sync_soledad_error) d.addCallbacks(self._process_doclist, self._sync_soledad_error) return d else: logger.debug("Already fetching mail.") def start_loop(self): """ Starts a loop to fetch mail. """ self._loop = LoopingCall(self.fetch) self._loop.start(self._check_period) def stop(self): """ Stops the loop that fetches mail. """ # XXX should cancel ongoing fetches too. if self._loop and self._loop.running is True: self._loop.stop() # # Private methods. # # synchronize incoming mail def _sync_soledad(self): """ Synchronizes with remote soledad. :returns: a list of LeapDocuments, or None. :rtype: iterable or None """ with self.fetching_lock: log.msg('syncing soledad...') self._soledad.sync() doclist = self._soledad.get_from_index("just-mail", "*") return doclist def _signal_unread_to_ui(self): """ Sends unread event to ui. """ leap_events.signal( IMAP_UNREAD_MAIL, str(self._inbox.getUnseenCount())) def _signal_fetch_to_ui(self, doclist): """ Sends leap events to ui. :param doclist: iterable with msg documents. :type doclist: iterable. :returns: doclist :rtype: iterable """ fetched_ts = time.mktime(time.gmtime()) num_mails = len(doclist) log.msg("there are %s mails" % (num_mails,)) leap_events.signal( IMAP_FETCHED_INCOMING, str(num_mails), str(fetched_ts)) self._signal_unread_to_ui() return doclist def _sync_soledad_error(self, failure): """ Errback for sync errors. """ # XXX should signal unrecoverable maybe. err = failure.value logger.error("error syncing soledad: %s" % (err,)) if failure.check(ssl.SSLError): logger.warning('SSL Error while ' 'syncing soledad: %r' % (err,)) elif failure.check(Exception): logger.warning('Unknown error while ' 'syncing soledad: %r' % (err,)) def _process_doclist(self, doclist): """ Iterates through the doclist, checks if each doc looks like a message, and yields a deferred that will decrypt and process the message. :param doclist: iterable with msg documents. :type doclist: iterable. :returns: a list of deferreds for individual messages. """ log.msg('processing doclist') if not doclist: logger.debug("no docs found") return num_mails = len(doclist) docs_cb = [] for index, doc in enumerate(doclist): logger.debug("processing doc %d of %d" % (index, num_mails)) leap_events.signal( IMAP_MSG_PROCESSING, str(index), str(num_mails)) keys = doc.content.keys() if self._is_msg(keys): # Ok, this looks like a legit msg. # Let's process it! encdata = doc.content[ENC_JSON_KEY] # Deferred chain for individual messages d = deferToThread(self._decrypt_msg, doc, encdata) d.addCallback(self._process_decrypted) d.addCallback(self._add_message_locally) docs_cb.append(d) else: # Ooops, this does not. logger.debug('This does not look like a proper msg.') return docs_cb # # operations on individual messages # def _is_msg(self, keys): """ Checks if the keys of a dictionary match the signature of the document type we use for messages. :param keys: iterable containing the strings to match. :type keys: iterable of strings. :rtype: bool """ return ENC_SCHEME_KEY in keys and ENC_JSON_KEY in keys def _decrypt_msg(self, doc, encdata): log.msg('decrypting msg') key = self._pkey try: decrdata = (self._keymanager.decrypt( encdata, key, passphrase=self._soledad.passphrase)) ok = True except Exception as exc: # XXX move this to errback !!! logger.warning("Error while decrypting msg: %r" % (exc,)) decrdata = "" ok = False leap_events.signal(IMAP_MSG_DECRYPTED, "1" if ok else "0") return doc, decrdata def _process_decrypted(self, msgtuple): """ Process a successfully decrypted message. :param msgtuple: a tuple consisting of a SoledadDocument instance containing the incoming message and data, the json-encoded, decrypted content of the incoming message :type msgtuple: (SoledadDocument, str) :returns: a SoledadDocument and the processed data. :rtype: (doc, data) """ doc, data = msgtuple msg = json.loads(data) if not isinstance(msg, dict): return False if not msg.get(self.INCOMING_KEY, False): return False # ok, this is an incoming message rawmsg = msg.get(self.CONTENT_KEY, None) if not rawmsg: return False data = self._maybe_decrypt_gpg_msg(rawmsg) return doc, data def _maybe_decrypt_gpg_msg(self, data): """ Tries to decrypt a gpg message if data looks like one. :param data: the text to be decrypted. :type data: str :return: data, possibly descrypted. :rtype: str """ parser = Parser() origmsg = parser.parsestr(data) # handle multipart/encrypted messages if origmsg.get_content_type() == 'multipart/encrypted': # sanity check payload = origmsg.get_payload() if len(payload) != 2: raise MalformedMessage( 'Multipart/encrypted messages should have exactly 2 body ' 'parts (instead of %d).' % len(payload)) if payload[0].get_content_type() != 'application/pgp-encrypted': raise MalformedMessage( "Multipart/encrypted messages' first body part should " "have content type equal to 'application/pgp-encrypted' " "(instead of %s)." % payload[0].get_content_type()) if payload[1].get_content_type() != 'application/octet-stream': raise MalformedMessage( "Multipart/encrypted messages' second body part should " "have content type equal to 'octet-stream' (instead of " "%s)." % payload[1].get_content_type()) # parse message and get encrypted content pgpencmsg = origmsg.get_payload()[1] encdata = pgpencmsg.get_payload() # decrypt and parse decrypted message decrdata = self._keymanager.decrypt( encdata, self._pkey, passphrase=self._soledad.passphrase) decrmsg = parser.parsestr(decrdata) # replace headers back in original message for hkey, hval in decrmsg.items(): try: # this will raise KeyError if header is not present origmsg.replace_header(hkey, hval) except KeyError: origmsg[hkey] = hval # replace payload by unencrypted payload origmsg.set_payload(decrmsg.get_payload()) return origmsg.as_string(unixfrom=False) else: PGP_BEGIN = "-----BEGIN PGP MESSAGE-----" PGP_END = "-----END PGP MESSAGE-----" # handle inline PGP messages if PGP_BEGIN in data: begin = data.find(PGP_BEGIN) end = data.rfind(PGP_END) pgp_message = data[begin:begin+end] decrdata = (self._keymanager.decrypt( pgp_message, self._pkey, passphrase=self._soledad.passphrase)) # replace encrypted by decrypted content data = data.replace(pgp_message, decrdata) # if message is not encrypted, return raw data return data def _add_message_locally(self, msgtuple): """ Adds a message to local inbox and delete it from the incoming db in soledad. :param msgtuple: a tuple consisting of a SoledadDocument instance containing the incoming message and data, the json-encoded, decrypted content of the incoming message :type msgtuple: (SoledadDocument, str) """ doc, data = msgtuple self._inbox.addMessage(data, (self.RECENT_FLAG,)) leap_events.signal(IMAP_MSG_SAVED_LOCALLY) doc_id = doc.doc_id self._soledad.delete_doc(doc) log.msg("deleted doc %s from incoming" % doc_id) leap_events.signal(IMAP_MSG_DELETED_INCOMING) self._signal_unread_to_ui()