diff options
| -rw-r--r-- | mail/src/leap/mail/imap/fetch.py | 72 |
1 files changed, 61 insertions, 11 deletions
diff --git a/mail/src/leap/mail/imap/fetch.py b/mail/src/leap/mail/imap/fetch.py index 4fb39100..2a430a0a 100644 --- a/mail/src/leap/mail/imap/fetch.py +++ b/mail/src/leap/mail/imap/fetch.py @@ -23,6 +23,8 @@ 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 @@ -43,6 +45,13 @@ 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. @@ -292,17 +301,58 @@ class LeapIncomingMail(object): :return: data, possibly descrypted. :rtype: str """ - PGP_BEGIN = "-----BEGIN PGP MESSAGE-----" - PGP_END = "-----END PGP MESSAGE-----" - 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)) - data = data.replace(pgp_message, decrdata) + 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): |