107 lines
3.0 KiB
Python
107 lines
3.0 KiB
Python
"""Mail operations for a given recipient.
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There are 3 operations available:
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- OpenPGPEncrypt: to deliver the message to a recipient with an OpenPGP public
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key available.
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- SMimeEncrypt: to deliver the message to a recipient with an S/MIME
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certificate.
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- KeepIntact: a no-operation (implementation of the Null Object pattern), used
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for messages already encrypted or those who haven't provided their keys or
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certificates.
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"""
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import logging
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import GnuPG
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LOG = logging.getLogger(__name__)
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class MailOperation:
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"""Contract for an operation to be performed on a message."""
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def __init__(self, recipients=[]):
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"""Initialise the operation with a recipient."""
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self._recipients = recipients
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def perform(self, message):
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"""Perform this operation on MESSAGE.
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Return target message.
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"""
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raise NotImplementedError(self.__class__())
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def recipients(self):
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"""Return list of recipients of the message."""
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return self._recipients
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def add_recipient(self, recipient):
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"""Register another message recipient."""
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self._recipients.append(recipient)
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class OpenPGPEncrypt(MailOperation):
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"""OpenPGP-encrypt the message."""
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def __init__(self, recipient, key, keyhome):
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"""Initialise encryption operation."""
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super().__init__(recipient)
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self._key = key
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self._keyhome = keyhome
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def perform(self, message):
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"""Encrypt MESSAGE with the given key."""
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enc = GnuPG.GPGEncryptor(self._keyhome)
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enc.update(message)
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encrypted, err = enc.encrypt()
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if err:
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LOG.error(f"Unable to encrypt message, delivering cleartext (gpg exit code: {err})")
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return message
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else:
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return encrypted
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def __repr__(self):
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"""Generate a representation with just method and key."""
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return f"<OpenPGP {self._recipient} {self._key}>"
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class SMimeEncrypt(MailOperation):
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"""S/MIME encryption operation."""
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def __init__(self, recipient, email, certificate):
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"""Initialise S/MIME encryption for a given EMAIL and CERTIFICATE."""
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super().__init__(recipient)
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self._email = email
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self._cert = certificate
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def perform(self, message):
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"""Encrypt with a certificate."""
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LOG.warning(f"Delivering clear-text to {self._recipient}")
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return message
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def __repr__(self):
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"""Generate a representation with just method and key."""
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return f"<S/MIME {self._recipient}, {self._cert}>"
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class KeepIntact(MailOperation):
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"""A do-nothing operation (Null Object implementation).
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This operation should be used for mail that's already encrypted.
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"""
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def __init__(self, recipient):
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"""Initialise pass-through operation for a given recipient."""
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super().__init__(recipient)
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def perform(self, message):
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"""Return MESSAGE unmodified."""
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return message
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def __repr__(self):
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"""Return representation with just method and email."""
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return f"<KeepIntact {self._recipient}>"
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