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from email.mime.application import MIMEApplication
from email.utils import getaddresses, parseaddr
from memoryhole.gpg import Gnupg
from memoryhole.rfc3156 import PGPEncrypted, MultipartEncrypted
class ProtectConfig(object):
PROTECTED_HEADERS = ('Subject', 'Message-ID', 'Date', 'To', 'From')
OBSCURED_HEADERS = ('Subject', 'Message-ID', 'Date', 'To', 'From')
def __init__(self, openpgp=None, protected_headers=PROTECTED_HEADERS,
obscured_headers=OBSCURED_HEADERS):
"""
Configuration parameters for the protection
:param openpgp: the implementation of openpgp to use for encryption
and/or signature
:type openpgp: IOpenPGP
:param protected_headers: list of headers to protect
:type protected_headers: [str]
:param obscured_headers: list of headers to obscure
:type obscured_headers: [str]
"""
if openpgp is None:
openpgp = Gnupg()
self.openpgp = openpgp
def protect(msg, encrypt=True, config=None):
"""
Protect an email with memory hole. It will protect the PROTECTED_HEADERS
and if obscure=True will obscure the OBSCURED_HEADERS
:param msg: the email to be protected
:type msg: Message
:param encrypt: should the message be encrypted
:type encrypt: bool
:return: an encrypted and/or signed email
:rtype: Message
"""
if config is None:
config = ProtectConfig()
if encrypt:
return _encrypt_mime(msg, config)
raise NotImplementedError()
def _encrypt_mime(msg, config):
encraddr = _recipient_addresses(msg)
signaddr = _from_address(msg)
newmsg = MultipartEncrypted('application/pgp-encrypted')
for hkey, hval in msg.items():
newmsg.add_header(hkey, hval)
del(msg[hkey])
encstr = config.openpgp.encrypt(msg.as_string(unixfrom=False),
encraddr, signaddr)
encmsg = MIMEApplication(
encstr, _subtype='octet-stream', _encoder=lambda x: x)
encmsg.add_header('content-disposition', 'attachment',
filename='msg.asc')
# create meta message
metamsg = PGPEncrypted()
metamsg.add_header('Content-Disposition', 'attachment')
# attach pgp message parts to new message
newmsg.attach(metamsg)
newmsg.attach(encmsg)
return newmsg
def _recipient_addresses(msg):
recipients = []
for header in ('to', 'cc', 'bcc'):
recipients += msg.get_all(header, [])
return [r[1] for r in getaddresses(recipients)]
def _from_address(msg):
frm = msg.get_all('From', [])
return parseaddr(frm)[1]
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