initial commit for edward-bot

[edward.git] / edward-bot

#! /usr/bin/env python3

"""*********************************************************************
* Edward is free software: you can redistribute it and/or modify       *
* it under the terms of the GNU Affero Public License as published by  *
* the Free Software Foundation, either version 3 of the License, or    *
* (at your option) any later version.                                  *
*                                                                      *
* Edward is distributed in the hope that it will be useful,            *
* but WITHOUT ANY WARRANTY; without even the implied warranty of       *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the        *
* GNU Affero Public License for more details.                          *
*                                                                      *
* You should have received a copy of the GNU Affero Public License     *
* along with Edward.  If not, see <http://www.gnu.org/licenses/>.      *
*                                                                      *
* Copyright (C) 2014-2015 Andrew Engelbrecht                (AGPLv3+)  *
* Copyright (C) 2014      Josh Drake                        (AGPLv3+)  *
* Copyright (C) 2014      Lisa Marie Maginnis               (AGPLv3+)  *
*                                                                      *
* Special thanks to Josh Drake for writing the original edward bot! :) *
*                                                                      *
************************************************************************

Code used from:

* http://agpl.fsf.org/emailselfdefense.fsf.org/edward/CURRENT/edward.tar.gz

"""

import sys
import email.parser
import gpgme
import re
import io
import time

def main ():

    txt = sys.stdin.read()

    msg = email.parser.Parser().parsestr(txt)

    print("From: " + msg['From'])
    print("Subject: " + msg['Subject'])
    print()

    msg_walk(msg)


def msg_walk (msg):

    for part in msg.walk():
        if part.get_content_type() == 'multipart':
            continue
        else:
            filename  = part.get_filename()
            conttype  = part.get_content_type()
            descrip_p = part.get_params(header='content-description')

            charset   = part.get_content_charset()
            payload_b = part.get_payload(decode=True)

            if payload_b == None:
                continue

            if descrip_p == None:
                decript = ""
            else:
                descript = descrip_p[0][0]

            if charset == None:
                charset = 'utf-8'

            payload = payload_b.decode(charset)

            if conttype == "application/pgp-encrypted":
                if descript == 'PGP/MIME version identification':
                    if payload.strip() != "Version: 1":
                        print("*** Warning... unknown pgp/mime version: " \
                                + payload.strip())
                continue

            if (filename == "encrypted.asc") or (conttype == "pgp/mime"):
                dec_msg = decrypt_payload(payload)
                print_decrypted(dec_msg)

            elif conttype == "text/plain":
                print(payload)

            else:
                print(payload)


def print_decrypted (message):

    if message == None:
        return

    for chunk in message:
        msg = email.parser.Parser().parsestr(chunk[0])
        sigs = chunk[1]

        msg_walk(msg)
        for sig in sigs:
            print_sig(sig)

def print_sig (sig):

        if sig.summary != 0:
            print("bad sig: " + str(sig.summary))
            #continue
        
        fpr = sig.fpr
        utc = time.gmtime(sig.timestamp)

        g = gpgme.Context()
        key = g.get_key(fpr)

        name = key.uids[0].name
        e_addr = key.uids[0].email
        comment = key.uids[0].comment

        date = "{0:0>4}-{1:0>2}-{2:0>2} {3}:{4}:{5} UTC".format(*utc)

        print("sig from: " + name + " (" + comment + ") <" \
                + e_addr + ">")
        print("fingerprint: " + fpr)
        print("date: " + date)


def decrypt_payload (payload):

    blocks = split_message(payload)
    message = decrypt_blocks(blocks)

    return message


def split_message (text):

    pgp_matches = re.search( \
            '(-----BEGIN PGP MESSAGE-----' \
            '.*' \
            '-----END PGP MESSAGE-----)', \
            text, \
            re.DOTALL)

    if pgp_matches == None:
        return None
    else:
        return pgp_matches.groups()


def decrypt_blocks (blocks):

    if blocks == None:
        return None

    message = []
    for block in blocks:
        plain, sigs = decrypt_block(block)

        message = message + [(plain, sigs)]

    return message


def decrypt_block (block):

    block_b = io.BytesIO(block.encode('ASCII'))
    plain_b = io.BytesIO()

    g = gpgme.Context()
    sigs = g.decrypt_verify(block_b, plain_b)

    plain = plain_b.getvalue().decode('ASCII')
    return (plain, sigs)


main()