559 lines
21 KiB
Python
559 lines
21 KiB
Python
"""
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This plugin implements `Off The Record messaging`_.
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This is a plugin used to encrypt one-to-one conversation using the OTR
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encryption method. You can use it if you want good privacy, deniability,
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authentication, and strong secrecy. Without this encryption, your messages
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are encrypted **at least** from your client (poezio) to your server. The
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message is decrypted by your server and you cannot control the encryption
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method of your messages from your server to your contact’s server (unless
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you are your own server’s administrator), nor from your contact’s server
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to your contact’s client.
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This plugin does end-to-end encryption. This means that **only** your contact can
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decrypt your messages, and it is fully encrypted during **all** its travel
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through the internet.
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Note that if you are having an encrypted conversation with a contact, you can
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**not** send XHTML-IM messages to him (or correct messages, or anything more than
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raw text). They will be removed and be replaced by plain text messages.
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This is a limitation of the OTR protocol, and it will never be fixed. Some clients
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like Pidgin-OTR try do do magic stuff with html unescaping inside the OTR body, and
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it is not pretty.
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Installation
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------------
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To use the OTR plugin, you must first install pure-python-otr.
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You have to install it from the git because a few issues were
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found with the python3 compatibility while writing this plugin,
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and the fixes did not make it into a stable release yet.
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Install the python module:
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.. code-block:: bash
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git clone https://github.com/afflux/pure-python-otr.git
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cd pure-python-otr
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python3 setup.py install --user
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You can also use pip with the requirements.txt at the root of
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the poezio directory.
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Usage
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-----
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Command added to Conversation Tabs and Private Tabs:
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.. glossary::
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/otr
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**Usage:** ``/otr [start|refresh|end|fpr|ourfpr|trust|untrust]``
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This command is used to manage an OTR private session.
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- The ``start`` (or ``refresh``) command starts or refreshs a private OTR session
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- The ``end`` command ends a private OTR session
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- The ``fpr`` command gives you the fingerprint of the key of the remove entity
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- The ``ourfpr`` command gives you the fingerprint of your own key
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- The ``trust`` command marks the current remote key as trusted for the current remote JID
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- The ``untrust`` command removes that trust
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- Finally, the ``drop`` command is used if you want to delete your private key (not recoverable).
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.. warning::
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With ``drop``, the private key is only removed from the filesystem, *NOT* with multiple rewrites in a secure
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manner, you should do that yourself if you want to be sure.
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To use OTR, make sure the plugin is loaded (if not, then do ``/load otr``).
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A simple workflow looks like this:
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.. code-block:: none
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/otr start
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The status of the OTR encryption should appear in the bar between the chat and
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the input as ``OTR: encrypted``.
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Then you use ``fpr``/``ourfpr`` to check the fingerprints, and confirm your respective
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identities out-of-band.
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You can then use
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.. code-block:: none
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/otr trust
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To set the key as trusted, which will be shown when you start or refresh a conversation
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(the trust status will be in a bold font and if the key is untrusted, the remote fingerprint
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will be shown).
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Once you’re done, end the OTR session with
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.. code-block:: none
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/otr end
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Files
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-----
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This plugin creates trust files complatible with libotr and the files produced by gajim.
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The files are located in :file:`$XDG_DATA_HOME/poezio/otr/` by default (so
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:file:`~/.local/share/poezio/otr` in most cases).
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Two files are created:
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- An account_jid.key3 (:file:`example@example.com.key3`) file, which contains the private key
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- An account_jid.fpr (:file:`example@example.com.fpr`) file, which contains the list of trusted
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(or untrusted) JIDs and keys.
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Configuration
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-------------
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.. glossary::
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:sorted:
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keys_dir
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**Default:** ``$XDG_DATA_HOME/poezio/otr``
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The directory in which you want keys and fpr to be stored.
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allow_v2
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**Default:** ``true``
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Allow OTRv2
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allow_v1
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**Default:** ``false``
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Allow OTRv1
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log
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**Default:** false
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Log conversations (OTR start/end marker, and messages).
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The :term:`allow_v1`, :term:`allow_v2` and :term:`log` configuration
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parameters are tab-specific.
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Important details
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-----------------
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The OTR session is considered for a full jid, but the trust is considered
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with a bare JID. This is important to know in the case of Private Chats, since
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you cannot always get the real the JID of your contact (or check if the same
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nick is used by different people).
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.. _Off The Record messaging: http://wiki.xmpp.org/web/OTR
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"""
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import potr
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import theming
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import logging
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log = logging.getLogger(__name__)
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import os
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import curses
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from potr.context import NotEncryptedError, UnencryptedMessage, ErrorReceived, NotOTRMessage,\
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STATE_ENCRYPTED, STATE_PLAINTEXT, STATE_FINISHED, Context, Account, crypt
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from plugin import BasePlugin
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from tabs import ConversationTab, DynamicConversationTab, PrivateTab
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from common import safeJID
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from config import config
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OTR_DIR = os.path.join(os.getenv('XDG_DATA_HOME') or
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'~/.local/share', 'poezio', 'otr')
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POLICY_FLAGS = {
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'ALLOW_V1':False,
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'ALLOW_V2':True,
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'REQUIRE_ENCRYPTION': False,
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'SEND_TAG': True,
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'WHITESPACE_START_AKE': True,
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'ERROR_START_AKE': True
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}
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log = logging.getLogger(__name__)
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def hl(tab):
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if tab.state != 'current':
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tab.state = 'private'
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conv_jid = safeJID(tab.name)
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if 'private' in config.get('beep_on', 'highlight private').split():
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if config.get_by_tabname('disable_beep', 'false', conv_jid.bare, False).lower() != 'true':
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curses.beep()
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class PoezioContext(Context):
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def __init__(self, account, peer, xmpp, core):
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super(PoezioContext, self).__init__(account, peer)
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self.xmpp = xmpp
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self.core = core
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self.flags = {}
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self.trustName = safeJID(peer).bare
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def getPolicy(self, key):
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if key in self.flags:
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return self.flags[key]
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else:
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return False
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def inject(self, msg, appdata=None):
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message = self.xmpp.make_message(mto=self.peer, mbody=msg.decode('ascii'), mtype='chat')
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message.enable('carbon_private')
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message.send()
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def setState(self, newstate):
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tab = self.core.get_tab_by_name(self.peer)
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if not tab:
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tab = self.core.get_tab_by_name(safeJID(self.peer).bare, DynamicConversationTab)
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if not tab.locked_resource == safeJID(self.peer).resource:
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tab = None
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if self.state == STATE_ENCRYPTED:
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if newstate == STATE_ENCRYPTED:
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log.debug('OTR conversation with %s refreshed', self.peer)
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if tab:
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if self.getCurrentTrust():
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tab.add_message('Refreshed \x19btrusted\x19o OTR conversation with %s' % self.peer, typ=self.log)
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else:
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tab.add_message('Refreshed \x19buntrusted\x19o OTR conversation with %s (key: %s)' %
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(self.peer, self.getCurrentKey()), typ=self.log)
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hl(tab)
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elif newstate == STATE_FINISHED or newstate == STATE_PLAINTEXT:
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log.debug('OTR conversation with %s finished', self.peer)
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if tab:
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tab.add_message('Ended OTR conversation with %s' % self.peer, typ=self.log)
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hl(tab)
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else:
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if newstate == STATE_ENCRYPTED:
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if tab:
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if self.getCurrentTrust():
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tab.add_message('Started \x19btrusted\x19o OTR conversation with %s' % self.peer, typ=self.log)
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else:
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tab.add_message('Started \x19buntrusted\x19o OTR conversation with %s (key: %s)' %
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(self.peer, self.getCurrentKey()), typ=self.log)
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hl(tab)
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log.debug('Set encryption state of %s to %s', self.peer, states[newstate])
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super(PoezioContext, self).setState(newstate)
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if tab:
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self.core.refresh_window()
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self.core.doupdate()
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class PoezioAccount(Account):
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def __init__(self, jid, key_dir):
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super(PoezioAccount, self).__init__(jid, 'xmpp', 1024)
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self.key_dir = os.path.join(key_dir, jid)
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def load_privkey(self):
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try:
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with open(self.key_dir + '.key3', 'rb') as keyfile:
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return potr.crypt.PK.parsePrivateKey(keyfile.read())[0]
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except:
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log.error('Error in load_privkey', exc_info=True)
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def drop_privkey(self):
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try:
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os.remove(self.key_dir + '.key3')
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except:
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log.exception('Error in drop_privkey (removing %s)', self.key_dir + '.key3')
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self.privkey = None
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def save_privkey(self):
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try:
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with open(self.key_dir + '.key3', 'xb') as keyfile:
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keyfile.write(self.getPrivkey().serializePrivateKey())
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except:
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log.error('Error in save_privkey', exc_info=True)
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def load_trusts(self):
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try:
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with open(self.key_dir + '.fpr', 'r') as fpr_fd:
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for line in fpr_fd:
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ctx, acc, proto, fpr, trust = line[:-1].split('\t')
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if acc != self.name or proto != 'xmpp':
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continue
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jid = safeJID(ctx).bare
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if not jid:
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continue
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self.setTrust(jid, fpr, trust)
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except:
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log.error('Error in load_trusts', exc_info=True)
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def save_trusts(self):
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try:
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with open(self.key_dir + '.fpr', 'w') as fpr_fd:
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for uid, trusts in self.trusts.items():
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for fpr, trustVal in trusts.items():
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fpr_fd.write('\t'.join(
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(uid, self.name, 'xmpp', fpr, trustVal)))
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fpr_fd.write('\n')
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except:
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log.exception('Error in save_trusts', exc_info=True)
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saveTrusts = save_trusts
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loadTrusts = load_trusts
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loadPrivkey = load_privkey
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savePrivkey = save_privkey
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states = {
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STATE_PLAINTEXT: 'plaintext',
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STATE_ENCRYPTED: 'encrypted',
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STATE_FINISHED: 'finished',
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}
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class Plugin(BasePlugin):
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def init(self):
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# set the default values from the config
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allow_v2 = self.config.get('allow_v2', 'true').lower()
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POLICY_FLAGS['ALLOW_V2'] = (allow_v2 != 'false')
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allow_v1 = self.config.get('allow_v1', 'false').lower()
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POLICY_FLAGS['ALLOW_v1'] = (allow_v1 == 'true')
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global OTR_DIR
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OTR_DIR = os.path.expanduser(self.config.get('keys_dir', '') or OTR_DIR)
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try:
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os.makedirs(OTR_DIR)
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except OSError as e:
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if e.errno != 17:
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self.api.information('The OTR-specific folder could not be created'
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' poezio will be unable to save keys and trusts', 'OTR')
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except:
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self.api.information('The OTR-specific folder could not be created'
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' poezio will be unable to save keys and trusts', 'OTR')
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self.api.add_event_handler('conversation_msg', self.on_conversation_msg)
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self.api.add_event_handler('private_msg', self.on_conversation_msg)
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self.api.add_event_handler('conversation_say_after', self.on_conversation_say)
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self.api.add_event_handler('private_say_after', self.on_conversation_say)
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ConversationTab.add_information_element('otr', self.display_encryption_status)
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PrivateTab.add_information_element('otr', self.display_encryption_status)
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self.account = PoezioAccount(self.core.xmpp.boundjid.bare, OTR_DIR)
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self.account.load_trusts()
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self.contexts = {}
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usage = '[start|refresh|end|fpr|ourfpr|drop|trust|untrust]'
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shortdesc = 'Manage an OTR conversation'
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desc = ('Manage an OTR conversation.\n'
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'start/refresh: Start or refresh a conversation\n'
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'end: End a conversation\n'
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'fpr: Show the fingerprint of the key of the remote user\n'
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'ourfpr: Show the fingerprint of your own key\n'
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'drop: Remove the current key (FOREVER)\n'
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'trust: Set this key for this contact as trusted\n'
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'untrust: Remove the trust for the key of this contact\n')
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self.api.add_tab_command(ConversationTab, 'otr', self.command_otr,
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help=desc,
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usage=usage,
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short=shortdesc,
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completion=self.completion_otr)
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self.api.add_tab_command(PrivateTab, 'otr', self.command_otr,
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help=desc,
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usage=usage,
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short=shortdesc,
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completion=self.completion_otr)
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def cleanup(self):
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ConversationTab.remove_information_element('otr')
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PrivateTab.remove_information_element('otr')
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def get_context(self, jid):
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jid = safeJID(jid).full
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if not jid in self.contexts:
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flags = POLICY_FLAGS.copy()
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policy = self.config.get_by_tabname('encryption_policy', 'ondemand', jid).lower()
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logging_policy = self.config.get_by_tabname('log', 'false', jid).lower()
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allow_v2 = self.config.get_by_tabname('allow_v2', 'true', jid).lower()
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flags['ALLOW_V2'] = (allow_v2 != 'false')
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allow_v1 = self.config.get_by_tabname('allow_v1', 'false', jid).lower()
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flags['ALLOW_V1'] = (allow_v1 == 'true')
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self.contexts[jid] = PoezioContext(self.account, jid, self.core.xmpp, self.core)
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self.contexts[jid].log = 1 if logging_policy != 'false' else 0
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self.contexts[jid].flags = flags
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return self.contexts[jid]
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def on_conversation_msg(self, msg, tab):
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try:
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ctx = self.get_context(msg['from'])
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txt, tlvs = ctx.receiveMessage(msg["body"].encode('utf-8'))
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except UnencryptedMessage as err:
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# received an unencrypted message inside an OTR session
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tab.add_message('The following message from %s was not encrypted:\n%s' % (msg['from'], err.args[0].decode('utf-8')),
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jid=msg['from'], nick_color=theming.get_theme().COLOR_REMOTE_USER,
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typ=0)
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del msg['body']
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del msg['html']
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hl(tab)
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self.core.refresh_window()
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return
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except ErrorReceived as err:
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# Received an OTR error
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tab.add_message('Received the following error from %s: %s' % (msg['from'], err.args[0]), typ=0)
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del msg['body']
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del msg['html']
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hl(tab)
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self.core.refresh_window()
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return
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except NotOTRMessage as err:
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# ignore non-otr messages
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# if we expected an OTR message, we would have
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# got an UnencryptedMesssage
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# but do an additional check because of a bug with py3k
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if ctx.state != STATE_PLAINTEXT or ctx.getPolicy('REQUIRE_ENCRYPTION'):
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tab.add_message('The following message from %s was not encrypted:\n%s' % (msg['from'], err.args[0].decode('utf-8')),
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jid=msg['from'], nick_color=theming.get_theme().COLOR_REMOTE_USER,
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typ=ctx.log)
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del msg['body']
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del msg['html']
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hl(tab)
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self.core.refresh_window()
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return
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return
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except NotEncryptedError as err:
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tab.add_message('An encrypted message from %s was received but is '
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'unreadable, as you are not currently communicating'
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' privately.' % msg['from'], jid=msg['from'],
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nick_color=theming.get_theme().COLOR_REMOTE_USER,
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typ=0)
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hl(tab)
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del msg['body']
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del msg['html']
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self.core.refresh_window()
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return
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except crypt.InvalidParameterError:
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tab.add_message('The message from %s could not be decrypted' %
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msg['from'], jid=msg['from'], typ=0,
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nick_color=theming.get_theme().COLOR_REMOTE_USER)
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hl(tab)
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del msg['body']
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del msg['html']
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self.core.refresh_window()
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return
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except:
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tab.add_message('An unspecified error in the OTR plugin occured', typ=0)
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log.error('Unspecified error in the OTR plugin', exc_info=True)
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return
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# remove xhtml
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del msg['html']
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del msg['body']
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if not txt:
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return
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if isinstance(tab, PrivateTab):
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user = tab.parent_muc.get_user_by_name(msg['from'].resource)
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else:
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user = None
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body = txt.decode()
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tab.add_message(body, nickname=tab.nick, jid=msg['from'],
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forced_user=user, typ=ctx.log, nick_color=theming.get_theme().COLOR_REMOTE_USER)
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hl(tab)
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self.core.refresh_window()
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del msg['body']
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def on_conversation_say(self, msg, tab):
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"""
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On message sent
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"""
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if isinstance(tab, DynamicConversationTab) and tab.locked_resource:
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name = safeJID(tab.name)
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name.resource = tab.locked_resource
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name = name.full
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else:
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name = tab.name
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ctx = self.contexts.get(name)
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if ctx and ctx.state == STATE_ENCRYPTED:
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ctx.sendMessage(0, msg['body'].encode('utf-8'))
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tab.add_message(msg['body'],
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nickname=self.core.own_nick or tab.own_nick,
|
||
nick_color=theming.get_theme().COLOR_OWN_NICK,
|
||
identifier=msg['id'],
|
||
jid=self.core.xmpp.boundjid,
|
||
typ=ctx.log)
|
||
# remove everything from the message so that it doesn’t get sent
|
||
del msg['body']
|
||
del msg['replace']
|
||
del msg['html']
|
||
|
||
def display_encryption_status(self, jid):
|
||
context = self.get_context(jid)
|
||
state = states[context.state]
|
||
return ' OTR: %s' % state
|
||
|
||
def command_otr(self, arg):
|
||
"""
|
||
/otr [start|refresh|end|fpr|ourfpr]
|
||
"""
|
||
arg = arg.strip()
|
||
tab = self.api.current_tab()
|
||
name = tab.name
|
||
if isinstance(tab, DynamicConversationTab) and tab.locked_resource:
|
||
name = safeJID(tab.name)
|
||
name.resource = tab.locked_resource
|
||
name = name.full
|
||
if arg == 'end': # close the session
|
||
context = self.get_context(name)
|
||
context.disconnect()
|
||
elif arg == 'start' or arg == 'refresh':
|
||
otr = self.get_context(name)
|
||
self.core.xmpp.send_message(mto=name, mtype='chat',
|
||
mbody=self.contexts[name].sendMessage(0, b'?OTRv?').decode())
|
||
elif arg == 'ourfpr':
|
||
fpr = self.account.getPrivkey()
|
||
self.api.information('Your OTR key fingerprint is %s' % fpr, 'OTR')
|
||
elif arg == 'fpr':
|
||
if name in self.contexts:
|
||
ctx = self.contexts[name]
|
||
self.api.information('The key fingerprint for %s is %s' % (name, ctx.getCurrentKey()) , 'OTR')
|
||
elif arg == 'drop':
|
||
# drop the privkey (and obviously, end the current conversations before that)
|
||
for context in self.contexts.values():
|
||
if context.state not in (STATE_FINISHED, STATE_PLAINTEXT):
|
||
context.disconnect()
|
||
self.account.drop_privkey()
|
||
tab.add_message('Private key dropped.', typ=0)
|
||
elif arg == 'trust':
|
||
ctx = self.get_context(name)
|
||
key = ctx.getCurrentKey()
|
||
if key:
|
||
fpr = key.cfingerprint()
|
||
else:
|
||
return
|
||
if not ctx.getCurrentTrust():
|
||
ctx.setTrust(fpr, 'verified')
|
||
self.account.saveTrusts()
|
||
tab.add_message('You added \x19b%s\x19o with key %s to your trusted list.' % (ctx.trustName, key), typ=0)
|
||
elif arg == 'untrust':
|
||
ctx = self.get_context(name)
|
||
key = ctx.getCurrentKey()
|
||
if key:
|
||
fpr = key.cfingerprint()
|
||
else:
|
||
return
|
||
if ctx.getCurrentTrust():
|
||
ctx.setTrust(fpr, '')
|
||
self.account.saveTrusts()
|
||
tab.add_message('You removed \x19b%s\x19o with key %s from your trusted list.' % (ctx.trustName, key), typ=0)
|
||
self.core.refresh_window()
|
||
|
||
def completion_otr(self, the_input):
|
||
return the_input.new_completion(['start', 'fpr', 'ourfpr', 'refresh', 'end', 'trust', 'untrust'], 1, quotify=False)
|
||
|