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authorTomás Touceda <chiiph@leap.se>2013-12-06 15:48:54 -0300
committerTomás Touceda <chiiph@leap.se>2013-12-06 15:48:54 -0300
commitdc45a6098b798a2866c2ab6af097307913cf542b (patch)
tree1601c24e2cd0d390532727a1206cffd189d01b8f /src/leap/mail/imap/fetch.py
parent46ccf635c44aeffb75c95845b8b4cc9ce2b1c4a4 (diff)
parent037a5c59f36a711d7588eab06810a9ffdf2474b0 (diff)
Merge branch 'release-0.3.8'0.3.8
Diffstat (limited to 'src/leap/mail/imap/fetch.py')
-rw-r--r--src/leap/mail/imap/fetch.py315
1 files changed, 224 insertions, 91 deletions
diff --git a/src/leap/mail/imap/fetch.py b/src/leap/mail/imap/fetch.py
index 3422ed5..14f7a9b 100644
--- a/src/leap/mail/imap/fetch.py
+++ b/src/leap/mail/imap/fetch.py
@@ -22,8 +22,12 @@ import json
import ssl
import threading
import time
+import copy
+from StringIO import StringIO
from email.parser import Parser
+from email.generator import Generator
+from email.utils import parseaddr
from twisted.python import log
from twisted.internet.task import LoopingCall
@@ -57,7 +61,15 @@ class MalformedMessage(Exception):
class LeapIncomingMail(object):
"""
- Fetches mail from the incoming queue.
+ Fetches and process mail from the incoming pool.
+
+ This object has public methods start_loop and stop that will
+ actually initiate a LoopingCall with check_period recurrency.
+ The LoopingCall itself will invoke the fetch method each time
+ that the check_period expires.
+
+ This loop will sync the soledad db with the remote server and
+ process all the documents found tagged as incoming mail.
"""
RECENT_FLAG = "\\Recent"
@@ -65,13 +77,23 @@ class LeapIncomingMail(object):
INCOMING_KEY = "incoming"
CONTENT_KEY = "content"
+ LEAP_SIGNATURE_HEADER = 'X-Leap-Signature'
+ """
+ Header added to messages when they are decrypted by the IMAP fetcher,
+ which states the validity of an eventual signature that might be included
+ in the encrypted blob.
+ """
+ LEAP_SIGNATURE_VALID = 'valid'
+ LEAP_SIGNATURE_INVALID = 'invalid'
+ LEAP_SIGNATURE_COULD_NOT_VERIFY = 'could not verify'
+
fetching_lock = threading.Lock()
def __init__(self, keymanager, soledad, imap_account,
check_period, userid):
"""
- Initialize LeapIMAP.
+ Initialize LeapIncomingMail..
:param keymanager: a keymanager instance
:type keymanager: keymanager.KeyManager
@@ -148,6 +170,7 @@ class LeapIncomingMail(object):
logger.warning("Tried to start an already running fetching loop.")
def stop(self):
+ # XXX change the name to stop_loop, for consistency.
"""
Stops the loop that fetches mail.
"""
@@ -171,7 +194,9 @@ class LeapIncomingMail(object):
with self.fetching_lock:
log.msg('syncing soledad...')
self._soledad.sync()
+ log.msg('soledad synced.')
doclist = self._soledad.get_from_index("just-mail", "*")
+
return doclist
def _signal_unread_to_ui(self):
@@ -235,6 +260,8 @@ class LeapIncomingMail(object):
err = failure.value
logger.error("error saving msg locally: %s" % (err,))
+ # process incoming mail.
+
def _process_doclist(self, doclist):
"""
Iterates through the doclist, checks if each doc
@@ -253,25 +280,21 @@ class LeapIncomingMail(object):
docs_cb = []
for index, doc in enumerate(doclist):
- logger.debug("processing doc %d of %d" % (index, num_mails))
+ logger.debug("processing doc %d of %d" % (index + 1, 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)
+
+ # XXX use an IConsumer instead... ?
+ d = deferToThread(self._decrypt_doc, doc)
+ d.addCallback(self._process_decrypted_doc)
d.addErrback(self._log_err)
d.addCallback(self._add_message_locally)
d.addErrback(self._log_err)
- # XXX check this, add_locally should not get called if we
- # get an error in process
- #d.addCallbacks(self._process_decrypted, self._decryption_error)
- #d.addCallbacks(self._add_message_locally, self._saving_error)
docs_cb.append(d)
else:
# Ooops, this does not.
@@ -293,34 +316,44 @@ class LeapIncomingMail(object):
"""
return ENC_SCHEME_KEY in keys and ENC_JSON_KEY in keys
- def _decrypt_msg(self, doc, encdata):
+ def _decrypt_doc(self, doc):
+ """
+ Decrypt the contents of a document.
+
+ :param doc: A document containing an encrypted message.
+ :type doc: SoledadDocument
+
+ :return: A tuple containing the document and the decrypted message.
+ :rtype: (SoledadDocument, str)
+ """
log.msg('decrypting msg')
- key = self._pkey
+ success = False
+
try:
- decrdata = (self._keymanager.decrypt(
- encdata, key,
- passphrase=self._soledad.passphrase))
- ok = True
+ decrdata = self._keymanager.decrypt(
+ doc.content[ENC_JSON_KEY],
+ self._pkey)
+ success = True
except Exception as exc:
# XXX move this to errback !!!
- logger.warning("Error while decrypting msg: %r" % (exc,))
+ logger.error("Error while decrypting msg: %r" % (exc,))
decrdata = ""
- ok = False
- leap_events.signal(IMAP_MSG_DECRYPTED, "1" if ok else "0")
+ leap_events.signal(IMAP_MSG_DECRYPTED, "1" if success else "0")
return doc, decrdata
- def _process_decrypted(self, msgtuple):
+ def _process_decrypted_doc(self, msgtuple):
"""
- Process a successfully decrypted message.
+ Process a document containing a succesfully 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.
+ :return: a SoledadDocument and the processed data.
:rtype: (doc, data)
"""
+ log.msg('processing decrypted doc')
doc, data = msgtuple
msg = json.loads(data)
if not isinstance(msg, dict):
@@ -332,14 +365,10 @@ class LeapIncomingMail(object):
rawmsg = msg.get(self.CONTENT_KEY, None)
if not rawmsg:
return False
- try:
- data = self._maybe_decrypt_gpg_msg(rawmsg)
- return doc, data
- except keymanager_errors.EncryptionDecryptionFailed as exc:
- logger.error(exc)
- raise
+ data = self._maybe_decrypt_msg(rawmsg)
+ return doc, data
- def _maybe_decrypt_gpg_msg(self, data):
+ def _maybe_decrypt_msg(self, data):
"""
Tries to decrypt a gpg message if data looks like one.
@@ -348,80 +377,183 @@ class LeapIncomingMail(object):
:return: data, possibly descrypted.
:rtype: str
"""
- # TODO split this method
+ log.msg('maybe decrypting doc')
leap_assert_type(data, unicode)
+ # parse the original message
parser = Parser()
encoding = get_email_charset(data)
data = data.encode(encoding)
- 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)
+ msg = parser.parsestr(data)
+
+ # try to obtain sender public key
+ senderPubkey = None
+ fromHeader = msg.get('from', None)
+ if fromHeader is not None:
+ _, senderAddress = parseaddr(fromHeader)
try:
- decrdata = decrdata.encode(encoding)
- except (UnicodeEncodeError, UnicodeDecodeError) as e:
- logger.error("Unicode error {0}".format(e))
- decrdata = decrdata.encode(encoding, 'replace')
-
- decrmsg = parser.parsestr(decrdata)
- # remove original message's multipart/encrypted content-type
- del(origmsg['content-type'])
- # 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)
+ senderPubkey = self._keymanager.get_key(
+ senderAddress, OpenPGPKey)
+ except keymanager_errors.KeyNotFound:
+ pass
+
+ valid_sig = False # we will add a header saying if sig is valid
+ if msg.get_content_type() == 'multipart/encrypted':
+ decrmsg, valid_sig = self._decrypt_multipart_encrypted_msg(
+ msg, encoding, senderPubkey)
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))
+ decrmsg, valid_sig = self._maybe_decrypt_inline_encrypted_msg(
+ msg, encoding, senderPubkey)
+
+ # add x-leap-signature header
+ if senderPubkey is None:
+ decrmsg.add_header(
+ self.LEAP_SIGNATURE_HEADER,
+ self.LEAP_SIGNATURE_COULD_NOT_VERIFY)
+ else:
+ decrmsg.add_header(
+ self.LEAP_SIGNATURE_HEADER,
+ self.LEAP_SIGNATURE_VALID if valid_sig else
+ self.LEAP_SIGNATURE_INVALID,
+ pubkey=senderPubkey.key_id)
+
+ return decrmsg.as_string()
+
+ def _decrypt_multipart_encrypted_msg(self, msg, encoding, senderPubkey):
+ """
+ Decrypt a message with content-type 'multipart/encrypted'.
+
+ :param msg: The original encrypted message.
+ :type msg: Message
+ :param encoding: The encoding of the email message.
+ :type encoding: str
+ :param senderPubkey: The key of the sender of the message.
+ :type senderPubkey: OpenPGPKey
+
+ :return: A unitary tuple containing a decrypted message.
+ :rtype: (Message)
+ """
+ log.msg('decrypting multipart encrypted msg')
+ msg = copy.deepcopy(msg)
+ # sanity check
+ payload = msg.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 = msg.get_payload()[1]
+ encdata = pgpencmsg.get_payload()
+ # decrypt or fail gracefully
+ try:
+ decrdata, valid_sig = self._decrypt_and_verify_data(
+ encdata, senderPubkey)
+ except keymanager_errors.DecryptError as e:
+ logger.warning('Failed to decrypt encrypted message (%s). '
+ 'Storing message without modifications.' % str(e))
+ return msg, False # return original message
+ # decrypted successully, now fix encoding and parse
+ try:
+ decrdata = decrdata.encode(encoding)
+ except (UnicodeEncodeError, UnicodeDecodeError) as e:
+ logger.error("Unicode error {0}".format(e))
+ decrdata = decrdata.encode(encoding, 'replace')
+ parser = Parser()
+ decrmsg = parser.parsestr(decrdata)
+ # remove original message's multipart/encrypted content-type
+ del(msg['content-type'])
+ # replace headers back in original message
+ for hkey, hval in decrmsg.items():
+ try:
+ # this will raise KeyError if header is not present
+ msg.replace_header(hkey, hval)
+ except KeyError:
+ msg[hkey] = hval
+ # replace payload by unencrypted payload
+ msg.set_payload(decrmsg.get_payload())
+ return msg, valid_sig
+
+ def _maybe_decrypt_inline_encrypted_msg(self, origmsg, encoding,
+ senderPubkey):
+ """
+ Possibly decrypt an inline OpenPGP encrypted message.
+
+ :param origmsg: The original, possibly encrypted message.
+ :type origmsg: Message
+ :param encoding: The encoding of the email message.
+ :type encoding: str
+ :param senderPubkey: The key of the sender of the message.
+ :type senderPubkey: OpenPGPKey
+
+ :return: A unitary tuple containing a decrypted message.
+ :rtype: (Message)
+ """
+ log.msg('maybe decrypting inline encrypted msg')
+ # serialize the original message
+ buf = StringIO()
+ g = Generator(buf)
+ g.flatten(origmsg)
+ data = buf.getvalue()
+ # handle exactly one inline PGP message
+ PGP_BEGIN = "-----BEGIN PGP MESSAGE-----"
+ PGP_END = "-----END PGP MESSAGE-----"
+ valid_sig = False
+ if PGP_BEGIN in data:
+ begin = data.find(PGP_BEGIN)
+ end = data.find(PGP_END)
+ pgp_message = data[begin:end+len(PGP_END)]
+ try:
+ decrdata, valid_sig = self._decrypt_and_verify_data(
+ pgp_message, senderPubkey)
# replace encrypted by decrypted content
data = data.replace(pgp_message, decrdata)
+ except keymanager_errors.DecryptError:
+ logger.warning('Failed to decrypt potential inline encrypted '
+ 'message. Storing message as is...')
# if message is not encrypted, return raw data
-
if isinstance(data, unicode):
data = data.encode(encoding, 'replace')
+ parser = Parser()
+ return parser.parsestr(data), valid_sig
- return data
+ def _decrypt_and_verify_data(self, data, senderPubkey):
+ """
+ Decrypt C{data} using our private key and attempt to verify a
+ signature using C{senderPubkey}.
+
+ :param data: The text to be decrypted.
+ :type data: unicode
+ :param senderPubkey: The public key of the sender of the message.
+ :type senderPubkey: OpenPGPKey
+
+ :return: The decrypted data and a boolean stating whether the
+ signature could be verified.
+ :rtype: (str, bool)
+
+ :raise DecryptError: Raised if failed to decrypt.
+ """
+ log.msg('decrypting and verifying data')
+ valid_sig = False
+ try:
+ decrdata = self._keymanager.decrypt(
+ data, self._pkey,
+ verify=senderPubkey)
+ if senderPubkey is not None:
+ valid_sig = True
+ except keymanager_errors.InvalidSignature:
+ decrdata = self._keymanager.decrypt(
+ data, self._pkey)
+ return decrdata, valid_sig
def _add_message_locally(self, msgtuple):
"""
@@ -434,6 +566,7 @@ class LeapIncomingMail(object):
incoming message
:type msgtuple: (SoledadDocument, str)
"""
+ log.msg('adding message to local db')
doc, data = msgtuple
self._inbox.addMessage(data, (self.RECENT_FLAG,))
leap_events.signal(IMAP_MSG_SAVED_LOCALLY)