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0bec96d6 AE |
1 | #! /usr/bin/env python3 |
2 | ||
3 | """********************************************************************* | |
4 | * Edward is free software: you can redistribute it and/or modify * | |
5 | * it under the terms of the GNU Affero Public License as published by * | |
6 | * the Free Software Foundation, either version 3 of the License, or * | |
7 | * (at your option) any later version. * | |
8 | * * | |
9 | * Edward is distributed in the hope that it will be useful, * | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of * | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * | |
12 | * GNU Affero Public License for more details. * | |
13 | * * | |
14 | * You should have received a copy of the GNU Affero Public License * | |
15 | * along with Edward. If not, see <http://www.gnu.org/licenses/>. * | |
16 | * * | |
17 | * Copyright (C) 2014-2015 Andrew Engelbrecht (AGPLv3+) * | |
18 | * Copyright (C) 2014 Josh Drake (AGPLv3+) * | |
19 | * Copyright (C) 2014 Lisa Marie Maginnis (AGPLv3+) * | |
8bdfb6d4 AE |
20 | * Copyright (C) 2009-2015 Tails developers <tails@boum.org> ( GPLv3+) * |
21 | * Copyright (C) 2009 W. Trevor King <wking@drexel.edu> ( GPLv2+) * | |
0bec96d6 AE |
22 | * * |
23 | * Special thanks to Josh Drake for writing the original edward bot! :) * | |
24 | * * | |
25 | ************************************************************************ | |
26 | ||
a5385c04 | 27 | Code sourced from these projects: |
0bec96d6 | 28 | |
8bdfb6d4 AE |
29 | * http://agpl.fsf.org/emailselfdefense.fsf.org/edward/CURRENT/edward.tar.gz |
30 | * https://git-tails.immerda.ch/whisperback/tree/whisperBack/encryption.py?h=feature/python3 | |
31 | * http://www.physics.drexel.edu/~wking/code/python/send_pgp_mime | |
0bec96d6 AE |
32 | |
33 | """ | |
34 | ||
35 | import sys | |
0bec96d6 AE |
36 | import gpgme |
37 | import re | |
38 | import io | |
40c37ab3 | 39 | import os |
0bec96d6 | 40 | |
8bdfb6d4 AE |
41 | import email.parser |
42 | import email.message | |
43 | import email.encoders | |
44 | ||
45 | from email.mime.multipart import MIMEMultipart | |
46 | from email.mime.application import MIMEApplication | |
47 | from email.mime.nonmultipart import MIMENonMultipart | |
48 | ||
40c37ab3 | 49 | import edward_config |
c96f3837 | 50 | |
0bec96d6 AE |
51 | def main (): |
52 | ||
20f6e7c5 | 53 | handle_args() |
0bec96d6 | 54 | |
c96f3837 | 55 | email_text = sys.stdin.read() |
65ed3800 AE |
56 | email_from, email_subject = email_from_subject(email_text) |
57 | ||
40c37ab3 AE |
58 | os.environ['GNUPGHOME'] = edward_config.gnupghome |
59 | gpgme_ctx = gpgme.Context() | |
60 | gpgme_ctx.armor = True | |
61 | ||
62 | plaintext, keys = email_decode_flatten(email_text, gpgme_ctx) | |
1da9b527 | 63 | encrypt_to_key = choose_reply_encryption_key(keys) |
fafa21c3 | 64 | |
1da9b527 | 65 | reply_message = generate_reply(plaintext, email_from, \ |
897cbaf6 | 66 | email_subject, encrypt_to_key, |
40c37ab3 AE |
67 | edward_config.sign_with_key, |
68 | gpgme_ctx) | |
c96f3837 | 69 | |
1da9b527 | 70 | print(reply_message) |
c96f3837 | 71 | |
0bec96d6 | 72 | |
40c37ab3 | 73 | def email_decode_flatten (email_text, gpgme_ctx): |
0bec96d6 | 74 | |
86663388 | 75 | body = "" |
394a1476 AE |
76 | keys = [] |
77 | ||
78 | email_struct = email.parser.Parser().parsestr(email_text) | |
79 | ||
80 | for subpart in email_struct.walk(): | |
8bb4b0d5 | 81 | |
394a1476 AE |
82 | payload, description, filename, content_type \ |
83 | = get_email_subpart_info(subpart) | |
0bec96d6 | 84 | |
394a1476 | 85 | if payload == "": |
8bb4b0d5 | 86 | continue |
0bec96d6 | 87 | |
394a1476 | 88 | if content_type == "multipart": |
d437f8b2 | 89 | continue |
0bec96d6 | 90 | |
394a1476 AE |
91 | if content_type == "application/pgp-encrypted": |
92 | if description == "PGP/MIME version identification": | |
8bb4b0d5 | 93 | if payload.strip() != "Version: 1": |
394a1476 AE |
94 | print(progname + ": Warning: unknown " \ |
95 | + description + ": " \ | |
20f6e7c5 | 96 | + payload.strip(), file=sys.stderr) |
8bb4b0d5 AE |
97 | continue |
98 | ||
d437f8b2 | 99 | |
394a1476 | 100 | if (filename == "encrypted.asc") or (content_type == "pgp/mime"): |
40c37ab3 | 101 | plaintext, more_keys = decrypt_text(payload, gpgme_ctx) |
0bec96d6 | 102 | |
394a1476 AE |
103 | body += plaintext |
104 | keys += more_keys | |
105 | ||
106 | elif content_type == "text/plain": | |
86663388 | 107 | body += payload + "\n" |
0bec96d6 | 108 | |
8bb4b0d5 | 109 | else: |
86663388 AE |
110 | body += payload + "\n" |
111 | ||
394a1476 | 112 | return body, keys |
86663388 | 113 | |
c96f3837 | 114 | |
65ed3800 | 115 | def email_from_subject (email_text): |
d437f8b2 | 116 | |
394a1476 | 117 | email_struct = email.parser.Parser().parsestr(email_text) |
d437f8b2 | 118 | |
394a1476 AE |
119 | email_from = email_struct['From'] |
120 | email_subject = email_struct['Subject'] | |
d437f8b2 | 121 | |
394a1476 | 122 | return email_from, email_subject |
d437f8b2 | 123 | |
d437f8b2 | 124 | |
394a1476 | 125 | def get_email_subpart_info (part): |
d437f8b2 | 126 | |
394a1476 AE |
127 | charset = part.get_content_charset() |
128 | payload_bytes = part.get_payload(decode=True) | |
d437f8b2 | 129 | |
394a1476 AE |
130 | filename = part.get_filename() |
131 | content_type = part.get_content_type() | |
132 | description_list = part.get_params(header='content-description') | |
d437f8b2 | 133 | |
394a1476 AE |
134 | if charset == None: |
135 | charset = 'utf-8' | |
0bec96d6 | 136 | |
394a1476 AE |
137 | if payload_bytes != None: |
138 | payload = payload_bytes.decode(charset) | |
139 | else: | |
140 | payload = "" | |
0bec96d6 | 141 | |
394a1476 AE |
142 | if description_list != None: |
143 | description = description_list[0][0] | |
144 | else: | |
145 | description = "" | |
0bec96d6 | 146 | |
394a1476 | 147 | return payload, description, filename, content_type |
0bec96d6 | 148 | |
0bec96d6 | 149 | |
40c37ab3 | 150 | def decrypt_text (gpg_text, gpgme_ctx): |
86663388 | 151 | |
394a1476 AE |
152 | body = "" |
153 | keys = [] | |
0bec96d6 | 154 | |
394a1476 | 155 | gpg_chunks = split_message(gpg_text) |
86663388 | 156 | |
40c37ab3 | 157 | plaintext_and_sigs_chunks = decrypt_chunks(gpg_chunks, gpgme_ctx) |
0bec96d6 | 158 | |
394a1476 AE |
159 | for chunk in plaintext_and_sigs_chunks: |
160 | plaintext = chunk[0] | |
161 | sigs = chunk[1] | |
9eb78301 | 162 | |
394a1476 | 163 | for sig in sigs: |
40c37ab3 | 164 | key = get_pub_key(sig, gpgme_ctx) |
394a1476 | 165 | keys += [key] |
0bec96d6 | 166 | |
394a1476 | 167 | # recursive for nested layers of mime and/or gpg |
40c37ab3 | 168 | plaintext, more_keys = email_decode_flatten(plaintext, gpgme_ctx) |
8bb4b0d5 | 169 | |
394a1476 AE |
170 | body += plaintext |
171 | keys += more_keys | |
8bb4b0d5 | 172 | |
394a1476 | 173 | return body, keys |
8bb4b0d5 | 174 | |
8bb4b0d5 | 175 | |
40c37ab3 | 176 | def get_pub_key (sig, gpgme_ctx): |
9eb78301 | 177 | |
7b06b980 AE |
178 | fingerprint = sig.fpr |
179 | key = gpgme_ctx.get_key(fingerprint) | |
0bec96d6 | 180 | |
394a1476 | 181 | return key |
0bec96d6 AE |
182 | |
183 | ||
184 | def split_message (text): | |
185 | ||
7b06b980 | 186 | gpg_matches = re.search( \ |
394a1476 AE |
187 | '(-----BEGIN PGP MESSAGE-----' + \ |
188 | '.*' + \ | |
0bec96d6 AE |
189 | '-----END PGP MESSAGE-----)', \ |
190 | text, \ | |
f31ffe2f | 191 | flags=re.DOTALL) |
0bec96d6 | 192 | |
7b06b980 AE |
193 | if gpg_matches != None: |
194 | gpg_chunks = gpg_matches.groups() | |
0bec96d6 | 195 | else: |
7b06b980 AE |
196 | gpg_chunks = () |
197 | ||
198 | return gpg_chunks | |
0bec96d6 AE |
199 | |
200 | ||
40c37ab3 | 201 | def decrypt_chunks (gpg_chunks, gpgme_ctx): |
0bec96d6 | 202 | |
40c37ab3 | 203 | return [decrypt_chunk(chunk, gpgme_ctx) for chunk in gpg_chunks] |
0bec96d6 | 204 | |
0bec96d6 | 205 | |
40c37ab3 | 206 | def decrypt_chunk (gpg_chunk, gpgme_ctx): |
0bec96d6 | 207 | |
6aa41372 | 208 | chunk_b = io.BytesIO(gpg_chunk.encode('ascii')) |
0bec96d6 AE |
209 | plain_b = io.BytesIO() |
210 | ||
394a1476 | 211 | sigs = gpgme_ctx.decrypt_verify(chunk_b, plain_b) |
0bec96d6 | 212 | |
6aa41372 | 213 | plaintext = plain_b.getvalue().decode('utf-8') |
394a1476 | 214 | return (plaintext, sigs) |
0bec96d6 AE |
215 | |
216 | ||
fafa21c3 AE |
217 | def choose_reply_encryption_key (keys): |
218 | ||
219 | reply_key = None | |
220 | for key in keys: | |
221 | if (key.can_encrypt == True): | |
222 | reply_key = key | |
223 | break | |
224 | ||
216708e9 | 225 | return reply_key |
fafa21c3 AE |
226 | |
227 | ||
897cbaf6 | 228 | def generate_reply (plaintext, email_from, email_subject, encrypt_to_key, |
40c37ab3 | 229 | sign_with_fingerprint, gpgme_ctx): |
1da9b527 | 230 | |
8bdfb6d4 | 231 | |
1da9b527 AE |
232 | reply = "To: " + email_from + "\n" |
233 | reply += "Subject: " + email_subject + "\n" | |
216708e9 AE |
234 | |
235 | if (encrypt_to_key != None): | |
236 | plaintext_reply = "thanks for the message!\n\n\n" | |
237 | plaintext_reply += email_quote_text(plaintext) | |
238 | ||
8bdfb6d4 AE |
239 | # quoted printable encoding lets most ascii characters look normal |
240 | # before the decrypted mime message is decoded. | |
241 | char_set = email.charset.Charset("utf-8") | |
242 | char_set.body_encoding = email.charset.QP | |
243 | ||
244 | # MIMEText doesn't allow setting the text encoding | |
245 | # so we use MIMENonMultipart. | |
246 | plaintext_mime = MIMENonMultipart('text', 'plain') | |
247 | plaintext_mime.set_payload(plaintext_reply, charset=char_set) | |
248 | ||
249 | encrypted_text = encrypt_sign_message(plaintext_mime.as_string(), | |
250 | encrypt_to_key, | |
40c37ab3 AE |
251 | sign_with_fingerprint, |
252 | gpgme_ctx) | |
8bdfb6d4 AE |
253 | |
254 | control_mime = MIMEApplication("Version: 1", | |
255 | _subtype='pgp-encrypted', | |
256 | _encoder=email.encoders.encode_7or8bit) | |
257 | control_mime['Content-Description'] = 'PGP/MIME version identification' | |
258 | control_mime.set_charset('us-ascii') | |
259 | ||
260 | encoded_mime = MIMEApplication(encrypted_text, | |
261 | _subtype='octet-stream; name="encrypted.asc"', | |
262 | _encoder=email.encoders.encode_7or8bit) | |
263 | encoded_mime['Content-Description'] = 'OpenPGP encrypted message' | |
264 | encoded_mime['Content-Disposition'] = 'inline; filename="encrypted.asc"' | |
265 | encoded_mime.set_charset('us-ascii') | |
266 | ||
267 | message_mime = MIMEMultipart(_subtype="encrypted", protocol="application/pgp-encrypted") | |
268 | message_mime.attach(control_mime) | |
269 | message_mime.attach(encoded_mime) | |
270 | message_mime['Content-Disposition'] = 'inline' | |
216708e9 | 271 | |
8bdfb6d4 | 272 | reply += message_mime.as_string() |
216708e9 AE |
273 | |
274 | else: | |
8bdfb6d4 | 275 | reply += "\n" |
216708e9 AE |
276 | reply += "Sorry, i couldn't find your key.\n" |
277 | reply += "I'll need that to encrypt a message to you." | |
1da9b527 AE |
278 | |
279 | return reply | |
280 | ||
281 | ||
f87041f8 AE |
282 | def email_quote_text (text): |
283 | ||
284 | quoted_message = re.sub(r'^', r'> ', text, flags=re.MULTILINE) | |
285 | ||
286 | return quoted_message | |
287 | ||
288 | ||
40c37ab3 | 289 | def encrypt_sign_message (plaintext, encrypt_to_key, sign_with_fingerprint, gpgme_ctx): |
1da9b527 | 290 | |
897cbaf6 AE |
291 | sign_with_key = gpgme_ctx.get_key(sign_with_fingerprint) |
292 | gpgme_ctx.signers = [sign_with_key] | |
293 | ||
6aa41372 | 294 | plaintext_bytes = io.BytesIO(plaintext.encode('ascii')) |
1da9b527 AE |
295 | encrypted_bytes = io.BytesIO() |
296 | ||
897cbaf6 | 297 | gpgme_ctx.encrypt_sign([encrypt_to_key], gpgme.ENCRYPT_ALWAYS_TRUST, |
1da9b527 AE |
298 | plaintext_bytes, encrypted_bytes) |
299 | ||
6aa41372 | 300 | encrypted_txt = encrypted_bytes.getvalue().decode('ascii') |
1da9b527 AE |
301 | return encrypted_txt |
302 | ||
303 | ||
20f6e7c5 AE |
304 | def handle_args (): |
305 | if __name__ == "__main__": | |
306 | ||
307 | global progname | |
308 | progname = sys.argv[0] | |
309 | ||
310 | if len(sys.argv) > 1: | |
311 | print(progname + ": error, this program doesn't " \ | |
312 | "need any arguments.", file=sys.stderr) | |
313 | exit(1) | |
314 | ||
315 | ||
0bec96d6 AE |
316 | main() |
317 |