1 #! /usr/bin/env python3
2 # -*- coding: utf-8 -*-
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. *
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. *
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/>. *
17 * Copyright (C) 2014-2015 Andrew Engelbrecht (AGPLv3+) *
18 * Copyright (C) 2014 Josh Drake (AGPLv3+) *
19 * Copyright (C) 2014 Lisa Marie Maginnis (AGPLv3+) *
20 * Copyright (C) 2009-2015 Tails developers <tails@boum.org> ( GPLv3+) *
21 * Copyright (C) 2009 W. Trevor King <wking@drexel.edu> ( GPLv2+) *
23 * Special thanks to Josh Drake for writing the original edward bot! :) *
25 ************************************************************************
27 Code sourced from these projects:
29 * http://agpl.fsf.org/emailselfdefense.fsf.org/edward/PREVIOUS-20150530/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
47 from email
.mime
.text
import MIMEText
48 from email
.mime
.multipart
import MIMEMultipart
49 from email
.mime
.application
import MIMEApplication
50 from email
.mime
.nonmultipart
import MIMENonMultipart
54 langs
= ["de", "el", "en", "es", "fr", "it", "ja", "pt-br", "ro", "ru", "tr"]
56 """This list contains the abbreviated names of reply languages available to
59 class TxtType (enum
.Enum
):
67 match_pairs
= [(TxtType
.message
,
68 '-----BEGIN PGP MESSAGE-----.*?-----END PGP MESSAGE-----'),
70 '-----BEGIN PGP PUBLIC KEY BLOCK-----.*?-----END PGP PUBLIC KEY BLOCK-----'),
72 '-----BEGIN PGP SIGNATURE-----.*?-----END PGP SIGNATURE-----')]
74 """This list of tuples matches query names with re.search() queries used
75 to find GPG data for edward to process."""
78 class EddyMsg (object):
80 The EddyMsg class represents relevant parts of a mime message.
82 The represented message can be single-part or multi-part.
84 'multipart' is set to True if there are multiple mime parts.
86 'subparts' points to a list of mime sub-parts if it is a multi-part
87 message. Otherwise it points to an empty list.
89 'payload_bytes' is a binary representation of the mime part before header
90 removal and message decoding.
92 'payload_pieces' is a list of objects containing strings that when strung
93 together form the fully-decoded string representation of the mime part.
95 The 'filename', 'content_type', 'content_disposition' and
96 'description_list' come from the mime part parameters.
108 content_disposition
= None
109 description_list
= None
112 class PayloadPiece (object):
114 PayloadPiece represents a complte or sub-section of a mime part.
116 Instances of this class are often strung together within one or more arrays
117 pointed to by each instance of the EddyMsg class.
119 'piece_type' refers to an enum whose value describes the content of
120 'string'. Examples include TxtType.pubkey, for public keys, and
121 TxtType.message, for encrypted data (or armored signatures until they are
122 known to be such.) Some of the names derive from the header and footer of
123 each of these ascii-encoded gpg blocks.
125 'string' contains some string of text, such as non-GPG text, an encrypted
126 block of text, a signature, or a public key.
128 'gpg_data' points to any instances of GPGData that have been created based
129 on the contents of 'string'.
137 class GPGData (object):
139 GPGData holds info from decryption, sig. verification, and/or pub. keys.
141 Instances of this class contain decrypted information, signature
142 fingerprints and/or fingerprints of processed and imported public keys.
144 'decrypted' is set to True if 'plainobj' was created from encrypted data.
146 'plainobj' points to any decrypted, or signed part of, a GPG signature. It
147 is intended to be an instance of the EddyMsg class.
149 'sigs' is a list of fingerprints of keys used to sign the data in plainobj.
151 'sigkey_missing' is set to True if edward doesn't have the key it needs to
152 verify the signature on a block of text.
154 'key_cannot_encrypt' is set to True if pubkeys or sigs' keys in the payload
155 piece are not capable of encryption, are revoked or expired, for instance.
157 'keys' is a list of fingerprints of keys obtained in public key blocks.
164 sigkey_missing
= False
165 key_cannot_encrypt
= False
169 class ReplyInfo (object):
171 ReplyInfo contains details that edward uses in generating its reply.
173 Instances of this class contain information about whether a message was
174 successfully encrypted or signed, and whether a public key was attached, or
175 retrievable, from the local GPG store. It stores the fingerprints of
176 potential encryption key candidates and the message (if any at all) to
177 quote in edward's reply.
179 'replies' points one of the dictionaries of translated replies.
181 'target_key' refers to the fingerprint of a key used to sign encrypted
182 data. This is the preferred key, if it is set, and if is available.
184 'fallback_target_key' referst to the fingerprint of a key used to sign
185 unencrypted data; alternatively it may be a public key attached to the
188 'encrypt_to_key' the key object to use when encrypting edward's reply
190 'msg_to_quote' refers to the part of a message which edward should quote in
191 his reply. This should remain as None if there was no encrypted and singed
192 part. This is to avoid making edward a service for decrypting other
193 people's messages to edward.
195 'decrypt_success' is set to True if edward could decrypt part of the
198 'sig_success' is set to True if edward could to some extent verify the
199 signature of a signed part of the message to edward.
201 'key_can_encrypt' is set to True if a key which can be encrypted to has
204 'sig_failure' is set to True if edward could not verify a siganture.
206 'pubkey_success' is set to True if edward successfully imported a public
209 'sigkey_missing' is set to True if edward doesn't have the public key
210 needed for signature verification.
212 'key_cannot_encrypt' is set to True if pubkeys or sig's keys in a payload
213 piece of the message are not capable of encryption.
215 'have_repy_key' is set to True if edward has a public key to encrypt its
222 fallback_target_key
= None
223 encrypt_to_key
= None
226 decrypt_success
= False
228 pubkey_success
= False
229 key_can_encrypt
= False
231 decrypt_failure
= False
233 sigkey_missing
= False
234 key_cannot_encrypt
= False
236 have_reply_key
= False
242 This is the main function for edward, a GPG reply bot.
244 Edward responds to GPG-encrypted and signed mail, encrypting and signing
245 the response if the user's public key is, or was, included in the message.
254 Mime or plaintext email passing in through standard input. Portions of
255 the email may be encrypted. If the To: address contains the text
256 "edward-ja", then the reply will contain a reply written in the
257 Japanese language. There are other languages as well. The default
261 A reply email will be printed to standard output. The contents of the
262 reply email depends on whether the original email was encrypted or not,
263 has or doesn't have a signature, whether a public key used in the
264 original message is provided or locally stored, and the language
265 implied by the To: address in the original email.
268 print_reply_only
= handle_args()
270 gpgme_ctx
= get_gpg_context(edward_config
.gnupghome
,
271 edward_config
.sign_with_key
)
273 email_bytes
= sys
.stdin
.buffer.read()
275 parse_pgp_mime(email_bytes
, gpgme_ctx
)
276 email_struct
= parse_pgp_mime(email_bytes
, gpgme_ctx
)
278 email_to
, email_reply_to
, email_subject
= email_to_reply_to_subject(email_bytes
)
279 lang
, reply_from
= import_lang_pick_address(email_to
, edward_config
.hostname
)
281 replyinfo_obj
= ReplyInfo()
282 replyinfo_obj
.replies
= lang
.replies
284 prepare_for_reply(email_struct
, replyinfo_obj
)
285 get_key_from_fp(replyinfo_obj
, gpgme_ctx
)
286 reply_plaintext
= write_reply(replyinfo_obj
)
288 reply_mime
= generate_encrypted_mime(reply_plaintext
, email_reply_to
, \
289 email_subject
, replyinfo_obj
.encrypt_to_key
,
292 if print_reply_only
== True:
295 send_reply(reply_mime
, email_reply_to
, reply_from
)
298 def get_gpg_context (gnupghome
, sign_with_key_fp
):
300 This function returns the GPG context needed for encryption and signing.
302 The context is needed by other functions which use GPG functionality.
305 gnupghome: The path to "~/.gnupg/" or its alternative.
306 sign_with_key: The fingerprint of the key to sign with
309 A gpgme context to be used for GPG functions.
312 the 'armor' flag is set to True and the list of signing keys contains
313 the single specified key
316 os
.environ
['GNUPGHOME'] = gnupghome
318 gpgme_ctx
= gpgme
.Context()
319 gpgme_ctx
.armor
= True
322 sign_with_key
= gpgme_ctx
.get_key(sign_with_key_fp
)
323 except gpgme
.GpgmeError
:
324 error("unable to load signing key. is the gnupghome "
325 + "and signing key properly set in the edward_config.py?")
328 gpgme_ctx
.signers
= [sign_with_key
]
333 def parse_pgp_mime (email_bytes
, gpgme_ctx
):
334 """Parses the email for mime payloads and decrypts/verfies signatures.
336 This function creates a representation of a mime or plaintext email with
337 the EddyMsg class. It then splits each mime payload into one or more pieces
338 which may be plain text or GPG data. It then decrypts encrypted parts and
339 does some very basic signature verification on those parts.
342 email_bytes: an email message in byte string format
343 gpgme_ctx: a gpgme context
346 A message as an instance of EddyMsg
349 the returned EddyMsg instance has split, decrypted, verified and pubkey
353 email_struct
= email
.parser
.BytesParser().parsebytes(email_bytes
)
355 eddymsg_obj
= parse_mime(email_struct
)
356 split_payloads(eddymsg_obj
)
357 gpg_on_payloads(eddymsg_obj
, gpgme_ctx
)
362 def parse_mime(msg_struct
):
363 """Translates python's email.parser format into an EddyMsg format
365 If the message is multi-part, then a recursive object is created, where
366 each sub-part is also a EddyMsg instance.
369 msg_struct: an email parsed with email.parser.BytesParser(), which can be
373 an instance of EddyMsg, potentially a recursive one.
376 eddymsg_obj
= get_subpart_data(msg_struct
)
378 if msg_struct
.is_multipart() == True:
379 payloads
= msg_struct
.get_payload()
381 eddymsg_obj
.multipart
= True
382 eddymsg_obj
.subparts
= list(map(parse_mime
, payloads
))
387 def scan_and_split (payload_piece
, match_name
, pattern
):
388 """This splits the payloads of an EddyMsg object into GPG and text parts.
390 An EddyMsg object's payload_pieces starts off as a list containing a single
391 PayloadPiece object. This function returns a list of these objects which
392 have been split into GPG data and regular text, if such splits need to be/
396 payload_piece: a single payload or a split part of a payload
397 match_name: the type of data to try to spit out from the payload piece
398 pattern: the search pattern to be used for finding that type of data
401 a list of objects of the PayloadPiece class, in the order that the
402 string part of payload_piece originally was, broken up according to
403 matches specified by 'pattern'.
406 # don't try to re-split pieces containing gpg data
407 if payload_piece
.piece_type
!= TxtType
.text
:
408 return [payload_piece
]
410 flags
= re
.DOTALL | re
.MULTILINE
411 matches
= re
.search(pattern
, payload_piece
.string
, flags
=flags
)
414 pieces
= [payload_piece
]
418 beginning
= PayloadPiece()
419 beginning
.string
= payload_piece
.string
[:matches
.start()]
420 beginning
.piece_type
= payload_piece
.piece_type
422 match
= PayloadPiece()
423 match
.string
= payload_piece
.string
[matches
.start():matches
.end()]
424 match
.piece_type
= match_name
426 rest
= PayloadPiece()
427 rest
.string
= payload_piece
.string
[matches
.end():]
428 rest
.piece_type
= payload_piece
.piece_type
430 more_pieces
= scan_and_split(rest
, match_name
, pattern
)
431 pieces
= [beginning
, match
] + more_pieces
436 def get_subpart_data (part
):
437 """This function grabs information from a mime part.
439 It copies needed data from an email.parser.BytesParser() object over to an
443 part: an email.parser.BytesParser() object
451 mime_decoded_bytes
= part
.get_payload(decode
=True)
452 charset
= part
.get_content_charset()
454 # your guess is as good as a-myy-ee-ine...
458 payload_string
= part
.as_string()
459 if payload_string
!= None:
460 # convert each isolated carriage return or line feed to carriage return + line feed
461 payload_string_crlf
= re
.sub(r
'\n', '\r\n', re
.sub(r
'\r', '\n', re
.sub(r
'\r\n', '\n', payload_string
)))
462 obj
.payload_bytes
= payload_string_crlf
.encode(charset
)
464 obj
.filename
= part
.get_filename()
465 obj
.content_type
= part
.get_content_type()
466 obj
.content_disposition
= part
['content-disposition']
467 obj
.description_list
= part
['content-description']
469 if mime_decoded_bytes
!= None:
471 payload
= PayloadPiece()
472 payload
.string
= mime_decoded_bytes
.decode(charset
)
473 payload
.piece_type
= TxtType
.text
475 obj
.payload_pieces
= [payload
]
476 except UnicodeDecodeError:
482 def do_to_eddys_pieces (function_to_do
, eddymsg_obj
, data
):
483 """A function which maps another function onto a message's subparts.
485 This is a higer-order function which recursively performs a specified
486 function on each subpart of a multi-part message. Each single-part sub-part
487 has the function applied to it. This function also works if the part passed
491 function_to_do: function to perform on sub-parts
492 eddymsg_obj: a single part or multi-part EddyMsg object
493 data: a second argument to pass to 'function_to_do'
499 The passed-in EddyMsg object is transformed recursively on its
500 sub-parts according to 'function_to_do'.
503 if eddymsg_obj
.multipart
== True:
504 for sub
in eddymsg_obj
.subparts
:
505 do_to_eddys_pieces(function_to_do
, sub
, data
)
507 function_to_do(eddymsg_obj
, data
)
510 def split_payloads (eddymsg_obj
):
511 """Splits all (sub-)payloads of a message into GPG data and regular text.
513 Recursively performs payload splitting on all sub-parts of an EddyMsg
514 object into the various GPG data types, such as GPG messages, public key
515 blocks and signed text.
518 eddymsg_obj: an instance of EddyMsg
524 The EddyMsg object has payloads that are unsplit (by may be split)..
527 The EddyMsg object's payloads are all split into GPG and non-GPG parts.
530 for match_pair
in match_pairs
:
531 do_to_eddys_pieces(split_payload_pieces
, eddymsg_obj
, match_pair
)
534 def split_payload_pieces (eddymsg_obj
, match_pair
):
535 """A helper function for split_payloads(); works on PayloadPiece objects.
537 This function splits up PayloadPiece objects into multipe PayloadPiece
538 objects and replaces the EddyMsg object's previous list of payload pieces
539 with the new split up one.
542 eddymsg_obj: a single-part EddyMsg object.
543 match_pair: a tuple from the match_pairs list, which specifies a match
544 name and a match pattern.
550 The payload piece(s) of an EddyMsg object may be already split or
554 The EddyMsg object's payload piece(s) are split into a list of pieces
555 if matches of the match_pair are found.
558 (match_name
, pattern
) = match_pair
561 for piece
in eddymsg_obj
.payload_pieces
:
562 new_pieces_list
+= scan_and_split(piece
, match_name
, pattern
)
564 eddymsg_obj
.payload_pieces
= new_pieces_list
567 def gpg_on_payloads (eddymsg_obj
, gpgme_ctx
, prev_parts
=[]):
568 """Performs GPG operations on the GPG parts of the message
570 This function decrypts text, verifies signatures, and imports public keys
571 included in an email.
574 eddymsg_obj: an EddyMsg object with its payload_pieces split into GPG
575 and non-GPG sections by split_payloads()
576 gpgme_ctx: a gpgme context
578 prev_parts: a list of mime parts that occur before the eddymsg_obj
579 part, under the same multi-part mime part. This is used for
580 verifying detached signatures. For the root mime part, this should
581 be an empty list, which is the default value if this paramater is
588 eddymsg_obj should have its payloads split into gpg and non-gpg pieces.
591 Decryption, verification and key imports occur. the gpg_data members of
592 PayloadPiece objects get filled in with GPGData objects with some of
593 their attributes set.
596 if eddymsg_obj
.multipart
== True:
598 for sub
in eddymsg_obj
.subparts
:
599 gpg_on_payloads (sub
, gpgme_ctx
, prev_parts
)
604 for piece
in eddymsg_obj
.payload_pieces
:
606 if piece
.piece_type
== TxtType
.text
:
607 # don't transform the plaintext.
610 elif piece
.piece_type
== TxtType
.message
:
611 piece
.gpg_data
= GPGData()
613 (plaintext_b
, sigs
, sigkey_missing
, key_cannot_encrypt
) = decrypt_block(piece
.string
, gpgme_ctx
)
615 piece
.gpg_data
.sigkey_missing
= sigkey_missing
616 piece
.gpg_data
.key_cannot_encrypt
= key_cannot_encrypt
619 piece
.gpg_data
.decrypted
= True
620 piece
.gpg_data
.sigs
= sigs
622 piece
.gpg_data
.plainobj
= parse_pgp_mime(plaintext_b
, gpgme_ctx
)
625 # if not encrypted, check to see if this is an armored signature.
626 (plaintext_b
, sigs
, sigkey_missing
, key_cannot_encrypt
) = verify_sig_message(piece
.string
, gpgme_ctx
)
628 piece
.gpg_data
.sigkey_missing
= sigkey_missing
629 piece
.gpg_data
.key_cannot_encrypt
= key_cannot_encrypt
632 piece
.piece_type
= TxtType
.signature
633 piece
.gpg_data
.sigs
= sigs
635 piece
.gpg_data
.plainobj
= parse_pgp_mime(plaintext_b
, gpgme_ctx
)
637 elif piece
.piece_type
== TxtType
.pubkey
:
638 piece
.gpg_data
= GPGData()
640 (key_fps
, key_cannot_encrypt
) = add_gpg_key(piece
.string
, gpgme_ctx
)
642 piece
.gpg_data
.key_cannot_encrypt
= key_cannot_encrypt
645 piece
.gpg_data
.keys
= key_fps
647 elif piece
.piece_type
== TxtType
.detachedsig
:
648 piece
.gpg_data
= GPGData()
650 for prev
in prev_parts
:
651 (sig_fps
, sigkey_missing
, key_cannot_encrypt
) = verify_detached_signature(piece
.string
, prev
.payload_bytes
, gpgme_ctx
)
653 piece
.gpg_data
.sigkey_missing
= sigkey_missing
654 piece
.gpg_data
.key_cannot_encrypt
= key_cannot_encrypt
657 piece
.gpg_data
.sigs
= sig_fps
658 piece
.gpg_data
.plainobj
= prev
665 def prepare_for_reply (eddymsg_obj
, replyinfo_obj
):
666 """Updates replyinfo_obj with info on the message's GPG success/failures
668 This function marks replyinfo_obj with information about whether encrypted
669 text in eddymsg_obj was successfully decrypted, signatures were verified
670 and whether a public key was found or not.
673 eddymsg_obj: a message in the EddyMsg format
674 replyinfo_obj: an instance of ReplyInfo
680 eddymsg_obj has had its gpg_data created by gpg_on_payloads
683 replyinfo_obj has been updated with info about decryption/sig
684 verififcation status, etc. However the desired key isn't imported until
685 later, so the success or failure of that updates the values set here.
688 do_to_eddys_pieces(prepare_for_reply_pieces
, eddymsg_obj
, replyinfo_obj
)
690 def prepare_for_reply_pieces (eddymsg_obj
, replyinfo_obj
):
691 """A helper function for prepare_for_reply
693 It updates replyinfo_obj with GPG success/failure information, when
694 supplied a single-part EddyMsg object.
697 eddymsg_obj: a single-part message in the EddyMsg format
698 replyinfo_obj: an object which holds information about the message's
705 eddymsg_obj is a single-part message. (it may be a part of a multi-part
706 message.) It has had its gpg_data created by gpg_on_payloads if it has
710 replyinfo_obj has been updated with gpg success/failure information
713 for piece
in eddymsg_obj
.payload_pieces
:
714 if piece
.piece_type
== TxtType
.text
:
715 # don't quote the plaintext part.
718 elif piece
.piece_type
== TxtType
.message
:
719 prepare_for_reply_message(piece
, replyinfo_obj
)
721 elif piece
.piece_type
== TxtType
.pubkey
:
722 prepare_for_reply_pubkey(piece
, replyinfo_obj
)
724 elif (piece
.piece_type
== TxtType
.detachedsig
) \
725 or (piece
.piece_type
== TxtType
.signature
):
726 prepare_for_reply_sig(piece
, replyinfo_obj
)
729 def prepare_for_reply_message (piece
, replyinfo_obj
):
730 """Helper function for prepare_for_reply()
732 This function is called when the piece_type of a payload piece is
733 TxtType.message, or GPG Message block. This should be encrypted text. If
734 the encryted block is correclty signed, a sig will be attached to
735 .target_key unless there is already one there.
738 piece: a PayloadPiece object.
739 replyinfo_obj: object which gets updated with decryption status, etc.
745 the piece.payload_piece value should be TxtType.message.
748 replyinfo_obj gets updated with decryption status, signing status, a
749 potential signing key, posession status of the public key for the
750 signature and encryption capability status if that key is missing.
753 if piece
.gpg_data
.plainobj
== None:
754 replyinfo_obj
.decrypt_failure
= True
757 replyinfo_obj
.decrypt_success
= True
759 # we already have a key (and a message)
760 if replyinfo_obj
.target_key
!= None:
763 if piece
.gpg_data
.sigs
== []:
764 if piece
.gpg_data
.sigkey_missing
== True:
765 replyinfo_obj
.sigkey_missing
= True
767 if piece
.gpg_data
.key_cannot_encrypt
== True:
768 replyinfo_obj
.key_cannot_encrypt
= True
770 # only include a signed message in the reply.
771 get_signed_part
= True
774 replyinfo_obj
.target_key
= piece
.gpg_data
.sigs
[0]
775 replyinfo_obj
.sig_success
= True
776 get_signed_part
= False
778 flatten_decrypted_payloads(piece
.gpg_data
.plainobj
, replyinfo_obj
, get_signed_part
)
780 # to catch public keys in encrypted blocks
781 prepare_for_reply(piece
.gpg_data
.plainobj
, replyinfo_obj
)
784 def prepare_for_reply_pubkey (piece
, replyinfo_obj
):
785 """Helper function for prepare_for_reply(). Marks pubkey import status.
787 Marks replyinfo_obj with pub key import status.
790 piece: a PayloadPiece object
791 replyinfo_obj: a ReplyInfo object
794 piece.piece_type should be set to TxtType.pubkey .
797 replyinfo_obj has its fields updated.
800 if piece
.gpg_data
.keys
== []:
801 if piece
.gpg_data
.key_cannot_encrypt
== True:
802 replyinfo_obj
.key_cannot_encrypt
= True
804 replyinfo_obj
.pubkey_success
= True
806 # prefer public key as a fallback for the encrypted reply
807 replyinfo_obj
.fallback_target_key
= piece
.gpg_data
.keys
[0]
810 def prepare_for_reply_sig (piece
, replyinfo_obj
):
811 """Helper function for prepare_for_reply(). Marks sig verification status.
813 Marks replyinfo_obj with signature verification status.
816 piece: a PayloadPiece object
817 replyinfo_obj: a ReplyInfo object
820 piece.piece_type should be set to TxtType.signature, or
821 TxtType.detachedsig .
824 replyinfo_obj has its fields updated.
827 if piece
.gpg_data
.sigs
== []:
828 replyinfo_obj
.sig_failure
= True
830 if piece
.gpg_data
.sigkey_missing
== True:
831 replyinfo_obj
.sigkey_missing
= True
833 if piece
.gpg_data
.key_cannot_encrypt
== True:
834 replyinfo_obj
.key_cannot_encrypt
= True
837 replyinfo_obj
.sig_success
= True
839 if replyinfo_obj
.fallback_target_key
== None:
840 replyinfo_obj
.fallback_target_key
= piece
.gpg_data
.sigs
[0]
842 if (piece
.piece_type
== TxtType
.signature
):
843 # to catch public keys in signature blocks
844 prepare_for_reply(piece
.gpg_data
.plainobj
, replyinfo_obj
)
847 def flatten_decrypted_payloads (eddymsg_obj
, replyinfo_obj
, get_signed_part
):
848 """For creating a string representation of a signed, encrypted part.
850 When given a decrypted payload, it will add either the plaintext or signed
851 plaintext to the reply message, depeding on 'get_signed_part'. This is
852 useful for ensuring that the reply message only comes from a signed and
853 ecrypted GPG message. It also sets the target_key for encrypting the reply
854 if it's told to get signed text only.
857 eddymsg_obj: the message in EddyMsg format created by decrypting GPG
859 replyinfo_obj: a ReplyInfo object for holding the message to quote and
860 the target_key to encrypt to.
861 get_signed_part: True if we should only include text that contains a
862 further signature. If False, then include plain text.
868 The EddyMsg instance passed in should be a piece.gpg_data.plainobj
869 which represents decrypted text. It may or may not be signed on that
873 the ReplyInfo instance may have a new 'target_key' set and its
874 'msg_to_quote' will be updated with (possibly signed) plaintext, if any
878 if eddymsg_obj
== None:
881 # recurse on multi-part mime
882 if eddymsg_obj
.multipart
== True:
883 for sub
in eddymsg_obj
.subparts
:
884 flatten_decrypted_payloads(sub
, replyinfo_obj
, get_signed_part
)
886 for piece
in eddymsg_obj
.payload_pieces
:
887 if (get_signed_part
):
888 if ((piece
.piece_type
== TxtType
.detachedsig
) \
889 or (piece
.piece_type
== TxtType
.signature
)) \
890 and (piece
.gpg_data
!= None) \
891 and (piece
.gpg_data
.plainobj
!= None):
892 flatten_decrypted_payloads(piece
.gpg_data
.plainobj
, replyinfo_obj
, False)
893 replyinfo_obj
.target_key
= piece
.gpg_data
.sigs
[0]
896 if (eddymsg_obj
.content_disposition
== None \
897 or not eddymsg_obj
.content_disposition
.startswith("attachment")) \
898 and piece
.piece_type
== TxtType
.text
:
899 replyinfo_obj
.msg_to_quote
+= piece
.string
902 def get_key_from_fp (replyinfo_obj
, gpgme_ctx
):
903 """Obtains a public key object from a key fingerprint
905 If the .target_key is not set, then we use .fallback_target_key, if
909 replyinfo_obj: ReplyInfo instance
910 gpgme_ctx: the gpgme context
916 Loading a key requires that we have the public key imported. This
917 requires that they email contains the pub key block, or that it was
918 previously sent to edward.
921 If the key can be loaded, then replyinfo_obj.reply_to_key points to the
922 public key object. If the key cannot be loaded, then the replyinfo_obj
923 is marked as having no public key available. If the key is not capable
924 of encryption, it will not be used, and replyinfo_obj will be marked
928 for key
in (replyinfo_obj
.target_key
, replyinfo_obj
.fallback_target_key
):
931 encrypt_to_key
= gpgme_ctx
.get_key(key
)
933 except gpgme
.GpgmeError
:
936 if is_key_usable(encrypt_to_key
):
937 replyinfo_obj
.encrypt_to_key
= encrypt_to_key
938 replyinfo_obj
.have_reply_key
= True
939 replyinfo_obj
.key_can_encrypt
= True
943 replyinfo_obj
.key_cannot_encrypt
= True
947 def write_reply (replyinfo_obj
):
948 """Write the reply email body about the GPG successes/failures.
950 The reply is about whether decryption, sig verification and key
951 import/loading was successful or failed. If text was successfully decrypted
952 and verified, then the first instance of such text will be included in
956 replyinfo_obj: contains details of GPG processing status
959 the plaintext message to be sent to the user
962 replyinfo_obj should be populated with info about GPG processing status.
967 if (replyinfo_obj
.pubkey_success
== True):
968 reply_plain
+= replyinfo_obj
.replies
['greeting']
969 reply_plain
+= "\n\n"
972 if replyinfo_obj
.decrypt_success
== True:
973 debug('decrypt success')
974 reply_plain
+= replyinfo_obj
.replies
['success_decrypt']
976 if (replyinfo_obj
.sig_success
== True) and (replyinfo_obj
.have_reply_key
== True):
977 debug('message quoted')
978 reply_plain
+= replyinfo_obj
.replies
['space']
979 reply_plain
+= replyinfo_obj
.replies
['quote_follows']
980 reply_plain
+= "\n\n"
981 quoted_text
= email_quote_text(replyinfo_obj
.msg_to_quote
)
982 reply_plain
+= quoted_text
984 reply_plain
+= "\n\n"
986 elif replyinfo_obj
.decrypt_failure
== True:
987 debug('decrypt failure')
988 reply_plain
+= replyinfo_obj
.replies
['failed_decrypt']
989 reply_plain
+= "\n\n"
992 if replyinfo_obj
.sig_success
== True:
993 debug('signature success')
994 reply_plain
+= replyinfo_obj
.replies
['sig_success']
995 reply_plain
+= "\n\n"
997 elif replyinfo_obj
.sig_failure
== True:
998 debug('signature failure')
999 reply_plain
+= replyinfo_obj
.replies
['sig_failure']
1000 reply_plain
+= "\n\n"
1003 if (replyinfo_obj
.pubkey_success
== True):
1004 debug('public key received')
1005 reply_plain
+= replyinfo_obj
.replies
['public_key_received']
1006 reply_plain
+= "\n\n"
1008 elif (replyinfo_obj
.sigkey_missing
== True):
1009 debug('no public key')
1010 reply_plain
+= replyinfo_obj
.replies
['no_public_key']
1011 reply_plain
+= "\n\n"
1013 elif (replyinfo_obj
.key_can_encrypt
== False) \
1014 and (replyinfo_obj
.key_cannot_encrypt
== True):
1015 debug('bad public key')
1016 reply_plain
+= replyinfo_obj
.replies
['no_public_key']
1017 reply_plain
+= "\n\n"
1020 if (reply_plain
== ""):
1021 debug('plaintext message')
1022 reply_plain
+= replyinfo_obj
.replies
['failed_decrypt']
1023 reply_plain
+= "\n\n"
1026 reply_plain
+= replyinfo_obj
.replies
['signature']
1027 reply_plain
+= "\n\n"
1032 def add_gpg_key (key_block
, gpgme_ctx
):
1033 """Adds a GPG pubkey to the local keystore
1035 This adds keys received through email into the key store so they can be
1039 key_block: the string form of the ascii-armored public key block
1040 gpgme_ctx: the gpgme context
1043 the fingerprint(s) of the imported key(s) which can be used for
1044 encryption, and a boolean marking whether none of the keys are capable
1048 fp
= io
.BytesIO(key_block
.encode('ascii'))
1051 result
= gpgme_ctx
.import_(fp
)
1052 imports
= result
.imports
1053 except gpgme
.GpgmeError
:
1056 key_fingerprints
= []
1057 key_cannot_encrypt
= False
1059 for import_res
in imports
:
1060 fingerprint
= import_res
[0]
1063 key_obj
= gpgme_ctx
.get_key(fingerprint
)
1067 if key_obj
!= None and is_key_usable(key_obj
):
1068 key_fingerprints
+= [fingerprint
]
1069 key_cannot_encrypt
= False
1071 debug("added gpg key: " + fingerprint
)
1073 elif key_fingerprints
== []:
1074 key_cannot_encrypt
= True
1076 return (key_fingerprints
, key_cannot_encrypt
)
1079 def verify_sig_message (msg_block
, gpgme_ctx
):
1080 """Verifies the signature of a signed, ascii-armored block of text.
1082 It encodes the string into ascii, since binary GPG files are currently
1083 unsupported, and alternative, the ascii-armored format is encodable into
1087 msg_block: a GPG Message block in string form. It may be encrypted or
1088 not. If it is encrypted, it will return empty results.
1089 gpgme_ctx: the gpgme context
1092 A tuple containing the plaintext bytes of the signed part, the list of
1093 fingerprints of encryption-capable keys signing the data, a boolean
1094 marking whether edward is missing all public keys for validating any of
1095 the signatures, and a boolean marking whether all sigs' keys are
1096 incapable of encryption. If verification failed, perhaps because the
1097 message was also encrypted, sensible default values are returned.
1100 block_b
= io
.BytesIO(msg_block
.encode('ascii'))
1101 plain_b
= io
.BytesIO()
1104 sigs
= gpgme_ctx
.verify(block_b
, None, plain_b
)
1105 except gpgme
.GpgmeError
:
1106 return ("",[],False,False)
1108 plaintext_b
= plain_b
.getvalue()
1110 (fingerprints
, sigkey_missing
, key_cannot_encrypt
) = get_signature_fp(sigs
, gpgme_ctx
)
1112 return (plaintext_b
, fingerprints
, sigkey_missing
, key_cannot_encrypt
)
1115 def verify_detached_signature (detached_sig
, plaintext_bytes
, gpgme_ctx
):
1116 """Verifies the signature of a detached signature.
1118 This requires the signature part and the signed part as separate arguments.
1121 detached_sig: the signature part of the detached signature
1122 plaintext_bytes: the byte form of the message being signed.
1123 gpgme_ctx: the gpgme context
1126 A tuple containging a list of encryption capable signing fingerprints
1127 if the signature verification was sucessful, a boolean marking whether
1128 edward is missing all public keys for validating any of the signatures,
1129 and a boolean marking whether all signing keys are incapable of
1130 encryption. Otherwise, a tuple containing an empty list and True are
1134 detached_sig_fp
= io
.BytesIO(detached_sig
.encode('ascii'))
1135 plaintext_fp
= io
.BytesIO(plaintext_bytes
)
1138 sigs
= gpgme_ctx
.verify(detached_sig_fp
, plaintext_fp
, None)
1139 except gpgme
.GpgmeError
:
1140 return ([],False,False)
1142 (fingerprints
, sigkey_missing
, key_cannot_encrypt
) = get_signature_fp(sigs
, gpgme_ctx
)
1144 return (fingerprints
, sigkey_missing
, key_cannot_encrypt
)
1147 def decrypt_block (msg_block
, gpgme_ctx
):
1148 """Decrypts a block of GPG text and verifies any included sigatures.
1150 Some encypted messages have embeded signatures, so those are verified too.
1153 msg_block: the encrypted(/signed) text
1154 gpgme_ctx: the gpgme context
1157 A tuple containing plaintext bytes, encryption-capable signatures (if
1158 decryption and signature verification were successful, respectively), a
1159 boolean marking whether edward is missing all public keys for
1160 validating any of the signatures, and a boolean marking whether all
1161 signature keys are incapable of encryption.
1164 block_b
= io
.BytesIO(msg_block
.encode('ascii'))
1165 plain_b
= io
.BytesIO()
1168 sigs
= gpgme_ctx
.decrypt_verify(block_b
, plain_b
)
1169 except gpgme
.GpgmeError
:
1170 return ("",[],False,False)
1172 plaintext_b
= plain_b
.getvalue()
1174 (fingerprints
, sigkey_missing
, key_cannot_encrypt
) = get_signature_fp(sigs
, gpgme_ctx
)
1176 return (plaintext_b
, fingerprints
, sigkey_missing
, key_cannot_encrypt
)
1179 def get_signature_fp (sigs
, gpgme_ctx
):
1180 """Selects valid signatures from output of gpgme signature verifying functions
1182 get_signature_fp returns a list of valid signature fingerprints if those
1183 fingerprints are associated with available keys capable of encryption.
1186 sigs: a signature verification result object list
1187 gpgme_ctx: a gpgme context
1190 fingerprints: a list of fingerprints
1191 sigkey_missing: a boolean marking whether public keys are missing for
1192 all available signatures.
1193 key_cannot_encrypt: a boolearn marking whether available public keys are
1194 incapable of encryption.
1197 sigkey_missing
= False
1198 key_cannot_encrypt
= False
1202 if (sig
.summary
== 0) or (sig
.summary
& gpgme
.SIGSUM_VALID
!= 0) or (sig
.summary
& gpgme
.SIGSUM_GREEN
!= 0):
1204 key_obj
= gpgme_ctx
.get_key(sig
.fpr
)
1206 if fingerprints
== []:
1207 sigkey_missing
= True
1210 if is_key_usable(key_obj
):
1211 fingerprints
+= [sig
.fpr
]
1212 key_cannot_encrypt
= False
1213 sigkey_missing
= False
1215 elif fingerprints
== []:
1216 key_cannot_encrypt
= True
1218 elif fingerprints
== []:
1219 if (sig
.summary
& gpgme
.SIGSUM_KEY_MISSING
!= 0):
1220 sigkey_missing
= True
1222 return (fingerprints
, sigkey_missing
, key_cannot_encrypt
)
1225 def is_key_usable (key_obj
):
1226 """Returns boolean representing key usability regarding encryption
1228 Tests various feature of key and returns usability
1231 key_obj: a gpgme key object
1234 A boolean representing key usability
1236 if key_obj
.can_encrypt
and not key_obj
.invalid
and not key_obj
.expired \
1237 and not key_obj
.revoked
and not key_obj
.disabled
:
1243 def email_to_reply_to_subject (email_bytes
):
1244 """Returns the email's To:, Reply-To: (or From:), and Subject: fields
1246 Returns this information from an email.
1249 email_bytes: the byte string form of the email
1252 the email To:, Reply-To: (or From:), and Subject: fields as strings
1255 email_struct
= email
.parser
.BytesHeaderParser().parsebytes(email_bytes
)
1257 email_to
= email_struct
['To']
1258 email_from
= email_struct
['From']
1259 email_reply_to
= email_struct
['Reply-To']
1261 email_subject
= email_struct
['Subject']
1263 if email_reply_to
== None:
1264 email_reply_to
= email_from
1266 return email_to
, email_reply_to
, email_subject
1269 def import_lang_pick_address(email_to
, hostname
):
1270 """Imports language file for i18n support; makes reply from address
1272 The language imported depends on the To: address of the email received by
1273 edward. an -en ending implies the English language, whereas a -ja ending
1274 implies Japanese. The list of supported languages is listed in the 'langs'
1275 list at the beginning of the program. This function also chooses the
1276 language-dependent address which can be used as the From address in the
1280 email_to: the string containing the email address that the mail was
1282 hostname: the hostname part of the reply email's from address
1285 the reference to the imported language module. The only variable in
1286 this file is the 'replies' dictionary.
1292 if email_to
!= None:
1294 if "edward-" + lang
in email_to
:
1298 lang_mod_name
= "lang." + re
.sub('-', '_', use_lang
)
1299 lang_module
= importlib
.import_module(lang_mod_name
)
1301 reply_from
= "edward-" + use_lang
+ "@" + hostname
1303 return lang_module
, reply_from
1306 def generate_encrypted_mime (plaintext
, email_to
, email_subject
, encrypt_to_key
,
1308 """This function creates the mime email reply. It can encrypt the email.
1310 If the encrypt_key is included, then the email is encrypted and signed.
1311 Otherwise it is unencrypted.
1314 plaintext: the plaintext body of the message to create.
1315 email_to: the email address to reply to
1316 email_subject: the subject to use in reply
1317 encrypt_to_key: the key object to use for encrypting the email. (or
1319 gpgme_ctx: the gpgme context
1322 A string version of the mime message, possibly encrypted and signed.
1325 plaintext_mime
= MIMEText(plaintext
)
1326 plaintext_mime
.set_charset('utf-8')
1328 if (encrypt_to_key
!= None):
1330 encrypted_text
= encrypt_sign_message(plaintext_mime
.as_string(),
1334 control_mime
= MIMEApplication("Version: 1",
1335 _subtype
='pgp-encrypted',
1336 _encoder
=email
.encoders
.encode_7or8bit
)
1337 control_mime
['Content-Description'] = 'PGP/MIME version identification'
1338 control_mime
.set_charset('us-ascii')
1340 encoded_mime
= MIMEApplication(encrypted_text
,
1341 _subtype
='octet-stream; name="encrypted.asc"',
1342 _encoder
=email
.encoders
.encode_7or8bit
)
1343 encoded_mime
['Content-Description'] = 'OpenPGP encrypted message'
1344 encoded_mime
['Content-Disposition'] = 'inline; filename="encrypted.asc"'
1345 encoded_mime
.set_charset('us-ascii')
1347 message_mime
= MIMEMultipart(_subtype
="encrypted", protocol
="application/pgp-encrypted")
1348 message_mime
.attach(control_mime
)
1349 message_mime
.attach(encoded_mime
)
1350 message_mime
['Content-Disposition'] = 'inline'
1353 message_mime
= plaintext_mime
1355 message_mime
['To'] = email_to
1356 message_mime
['Subject'] = email_subject
1358 reply
= message_mime
.as_string()
1363 def send_reply(email_txt
, reply_to
, reply_from
):
1364 """Sends reply email
1366 Sent to original sender
1369 email_txt: message as a string
1370 reply_to: recipient of reply
1371 reply_from: edward's specific email address
1377 if reply_to
== None:
1378 error("*** ERROR: No one to send email to.")
1381 s
= smtplib
.SMTP('localhost')
1382 s
.sendmail(reply_from
, reply_to
, email_txt
)
1386 def email_quote_text (text
):
1387 """Quotes input text by inserting "> "s
1389 This is useful for quoting a text for the reply message. It inserts "> "
1390 strings at the beginning of lines.
1393 text: plain text to quote
1399 quoted_message
= re
.sub(r
'^', r
'> ', text
, flags
=re
.MULTILINE
)
1401 return quoted_message
1404 def encrypt_sign_message (plaintext
, encrypt_to_key
, gpgme_ctx
):
1405 """Encrypts and signs plaintext
1407 This encrypts and signs a message.
1410 plaintext: text to sign and ecrypt
1411 encrypt_to_key: the key object to encrypt to
1412 gpgme_ctx: the gpgme context
1415 An encrypted and signed string of text
1418 # the plaintext should be mime encoded in an ascii-compatible form
1419 plaintext_bytes
= io
.BytesIO(plaintext
.encode('ascii'))
1420 encrypted_bytes
= io
.BytesIO()
1422 gpgme_ctx
.encrypt_sign([encrypt_to_key
], gpgme
.ENCRYPT_ALWAYS_TRUST
,
1423 plaintext_bytes
, encrypted_bytes
)
1425 encrypted_txt
= encrypted_bytes
.getvalue().decode('ascii')
1426 return encrypted_txt
1429 def error (error_msg
):
1430 """Write an error message to stdout
1432 The error message includes the program name.
1435 error_msg: the message to print
1441 An error message is printed to stdout
1444 sys
.stderr
.write(progname
+ ": " + str(error_msg
) + "\n")
1447 def debug (debug_msg
):
1448 """Writes a debug message to stdout if debug == True
1450 If the debug option is set in edward_config.py, then the passed message
1451 gets printed to stdout.
1454 debug_msg: the message to print to stdout
1460 A debug message is printed to stdout
1463 if edward_config
.debug
== True:
1468 """Sets the progname variable and processes optional argument
1470 If there are more than two arguments then edward complains and quits. An
1471 single "-p" argument sets the print_reply_only option, which makes edward
1472 print email replies instead of mailing them.
1478 True if edward should print arguments instead of mailing them,
1479 otherwise it returns False.
1482 Exits with error 1 if there are more than two arguments, otherwise
1483 returns the print_reply_only option.
1487 progname
= sys
.argv
[0]
1489 print_reply_only
= False
1491 if len(sys
.argv
) > 2:
1492 print(progname
+ " usage: " + progname
+ " [-p]\n\n" \
1493 + " -p print reply message to stdout, do not mail it\n", \
1497 elif (len(sys
.argv
) == 2) and (sys
.argv
[1] == "-p"):
1498 print_reply_only
= True
1500 return print_reply_only
1503 if __name__
== "__main__":
1504 """Executes main if this file is not loaded interactively"""