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()
274 email_struct
= parse_pgp_mime(email_bytes
, gpgme_ctx
)
276 email_to
, email_reply_to
, email_subject
= email_to_reply_to_subject(email_bytes
)
277 lang
, reply_from
= import_lang_pick_address(email_to
, edward_config
.hostname
)
279 replyinfo_obj
= ReplyInfo()
280 replyinfo_obj
.replies
= lang
.replies
282 prepare_for_reply(email_struct
, replyinfo_obj
)
283 get_key_from_fp(replyinfo_obj
, gpgme_ctx
)
284 reply_plaintext
= write_reply(replyinfo_obj
)
286 reply_mime
= generate_encrypted_mime(reply_plaintext
, email_reply_to
, \
287 email_subject
, replyinfo_obj
.encrypt_to_key
,
290 if print_reply_only
== True:
293 send_reply(reply_mime
, email_reply_to
, reply_from
)
296 def get_gpg_context (gnupghome
, sign_with_key_fp
):
298 This function returns the GPG context needed for encryption and signing.
300 The context is needed by other functions which use GPG functionality.
303 gnupghome: The path to "~/.gnupg/" or its alternative.
304 sign_with_key: The fingerprint of the key to sign with
307 A gpgme context to be used for GPG functions.
310 the 'armor' flag is set to True and the list of signing keys contains
311 the single specified key
314 os
.environ
['GNUPGHOME'] = gnupghome
316 gpgme_ctx
= gpgme
.Context()
317 gpgme_ctx
.armor
= True
320 sign_with_key
= gpgme_ctx
.get_key(sign_with_key_fp
)
321 except gpgme
.GpgmeError
:
322 error("unable to load signing key. is the gnupghome "
323 + "and signing key properly set in the edward_config.py?")
326 gpgme_ctx
.signers
= [sign_with_key
]
331 def parse_pgp_mime (email_bytes
, gpgme_ctx
):
332 """Parses the email for mime payloads and decrypts/verfies signatures.
334 This function creates a representation of a mime or plaintext email with
335 the EddyMsg class. It then splits each mime payload into one or more pieces
336 which may be plain text or GPG data. It then decrypts encrypted parts and
337 does some very basic signature verification on those parts.
340 email_bytes: an email message in byte string format
341 gpgme_ctx: a gpgme context
344 A message as an instance of EddyMsg
347 the returned EddyMsg instance has split, decrypted, verified and pubkey
351 email_struct
= email
.parser
.BytesParser().parsebytes(email_bytes
)
353 eddymsg_obj
= parse_mime(email_struct
)
354 split_payloads(eddymsg_obj
)
355 gpg_on_payloads(eddymsg_obj
, gpgme_ctx
)
360 def parse_mime(msg_struct
):
361 """Translates python's email.parser format into an EddyMsg format
363 If the message is multi-part, then a recursive object is created, where
364 each sub-part is also a EddyMsg instance.
367 msg_struct: an email parsed with email.parser.BytesParser(), which can be
371 an instance of EddyMsg, potentially a recursive one.
374 eddymsg_obj
= get_subpart_data(msg_struct
)
376 if msg_struct
.is_multipart() == True:
377 payloads
= msg_struct
.get_payload()
379 eddymsg_obj
.multipart
= True
380 eddymsg_obj
.subparts
= list(map(parse_mime
, payloads
))
385 def scan_and_split (payload_piece
, match_name
, pattern
):
386 """This splits the payloads of an EddyMsg object into GPG and text parts.
388 An EddyMsg object's payload_pieces starts off as a list containing a single
389 PayloadPiece object. This function returns a list of these objects which
390 have been split into GPG data and regular text, if such splits need to be/
394 payload_piece: a single payload or a split part of a payload
395 match_name: the type of data to try to spit out from the payload piece
396 pattern: the search pattern to be used for finding that type of data
399 a list of objects of the PayloadPiece class, in the order that the
400 string part of payload_piece originally was, broken up according to
401 matches specified by 'pattern'.
404 # don't try to re-split pieces containing gpg data
405 if payload_piece
.piece_type
!= TxtType
.text
:
406 return [payload_piece
]
408 flags
= re
.DOTALL | re
.MULTILINE
409 matches
= re
.search(pattern
, payload_piece
.string
, flags
=flags
)
412 pieces
= [payload_piece
]
416 beginning
= PayloadPiece()
417 beginning
.string
= payload_piece
.string
[:matches
.start()]
418 beginning
.piece_type
= payload_piece
.piece_type
420 match
= PayloadPiece()
421 match
.string
= payload_piece
.string
[matches
.start():matches
.end()]
422 match
.piece_type
= match_name
424 rest
= PayloadPiece()
425 rest
.string
= payload_piece
.string
[matches
.end():]
426 rest
.piece_type
= payload_piece
.piece_type
428 more_pieces
= scan_and_split(rest
, match_name
, pattern
)
429 pieces
= [beginning
, match
] + more_pieces
434 def get_subpart_data (part
):
435 """This function grabs information from a mime part.
437 It copies needed data from an email.parser.BytesParser() object over to an
441 part: an email.parser.BytesParser() object
449 mime_decoded_bytes
= part
.get_payload(decode
=True)
450 charset
= part
.get_content_charset()
452 # your guess is as good as a-myy-ee-ine...
456 payload_string
= part
.as_string()
457 if payload_string
!= None:
458 # convert each isolated carriage return or line feed to carriage return + line feed
459 payload_string_crlf
= re
.sub(r
'\n', '\r\n', re
.sub(r
'\r', '\n', re
.sub(r
'\r\n', '\n', payload_string
)))
460 obj
.payload_bytes
= payload_string_crlf
.encode(charset
)
462 obj
.filename
= part
.get_filename()
463 obj
.content_type
= part
.get_content_type()
464 obj
.content_disposition
= part
['content-disposition']
465 obj
.description_list
= part
['content-description']
467 if mime_decoded_bytes
!= None:
469 payload
= PayloadPiece()
470 payload
.string
= mime_decoded_bytes
.decode(charset
)
471 payload
.piece_type
= TxtType
.text
473 obj
.payload_pieces
= [payload
]
474 except UnicodeDecodeError:
480 def do_to_eddys_pieces (function_to_do
, eddymsg_obj
, data
):
481 """A function which maps another function onto a message's subparts.
483 This is a higer-order function which recursively performs a specified
484 function on each subpart of a multi-part message. Each single-part sub-part
485 has the function applied to it. This function also works if the part passed
489 function_to_do: function to perform on sub-parts
490 eddymsg_obj: a single part or multi-part EddyMsg object
491 data: a second argument to pass to 'function_to_do'
497 The passed-in EddyMsg object is transformed recursively on its
498 sub-parts according to 'function_to_do'.
501 if eddymsg_obj
.multipart
== True:
502 for sub
in eddymsg_obj
.subparts
:
503 do_to_eddys_pieces(function_to_do
, sub
, data
)
505 function_to_do(eddymsg_obj
, data
)
508 def split_payloads (eddymsg_obj
):
509 """Splits all (sub-)payloads of a message into GPG data and regular text.
511 Recursively performs payload splitting on all sub-parts of an EddyMsg
512 object into the various GPG data types, such as GPG messages, public key
513 blocks and signed text.
516 eddymsg_obj: an instance of EddyMsg
522 The EddyMsg object has payloads that are unsplit (by may be split)..
525 The EddyMsg object's payloads are all split into GPG and non-GPG parts.
528 for match_pair
in match_pairs
:
529 do_to_eddys_pieces(split_payload_pieces
, eddymsg_obj
, match_pair
)
532 def split_payload_pieces (eddymsg_obj
, match_pair
):
533 """A helper function for split_payloads(); works on PayloadPiece objects.
535 This function splits up PayloadPiece objects into multipe PayloadPiece
536 objects and replaces the EddyMsg object's previous list of payload pieces
537 with the new split up one.
540 eddymsg_obj: a single-part EddyMsg object.
541 match_pair: a tuple from the match_pairs list, which specifies a match
542 name and a match pattern.
548 The payload piece(s) of an EddyMsg object may be already split or
552 The EddyMsg object's payload piece(s) are split into a list of pieces
553 if matches of the match_pair are found.
556 (match_name
, pattern
) = match_pair
559 for piece
in eddymsg_obj
.payload_pieces
:
560 new_pieces_list
+= scan_and_split(piece
, match_name
, pattern
)
562 eddymsg_obj
.payload_pieces
= new_pieces_list
565 def gpg_on_payloads (eddymsg_obj
, gpgme_ctx
, prev_parts
=[]):
566 """Performs GPG operations on the GPG parts of the message
568 This function decrypts text, verifies signatures, and imports public keys
569 included in an email.
572 eddymsg_obj: an EddyMsg object with its payload_pieces split into GPG
573 and non-GPG sections by split_payloads()
574 gpgme_ctx: a gpgme context
576 prev_parts: a list of mime parts that occur before the eddymsg_obj
577 part, under the same multi-part mime part. This is used for
578 verifying detached signatures. For the root mime part, this should
579 be an empty list, which is the default value if this paramater is
586 eddymsg_obj should have its payloads split into gpg and non-gpg pieces.
589 Decryption, verification and key imports occur. the gpg_data members of
590 PayloadPiece objects get filled in with GPGData objects with some of
591 their attributes set.
594 if eddymsg_obj
.multipart
== True:
596 for sub
in eddymsg_obj
.subparts
:
597 gpg_on_payloads (sub
, gpgme_ctx
, prev_parts
)
602 for piece
in eddymsg_obj
.payload_pieces
:
604 if piece
.piece_type
== TxtType
.text
:
605 # don't transform the plaintext.
608 elif piece
.piece_type
== TxtType
.message
:
609 piece
.gpg_data
= GPGData()
611 (plaintext_b
, sigs
, sigkey_missing
, key_cannot_encrypt
) = decrypt_block(piece
.string
, gpgme_ctx
)
613 piece
.gpg_data
.sigkey_missing
= sigkey_missing
614 piece
.gpg_data
.key_cannot_encrypt
= key_cannot_encrypt
617 piece
.gpg_data
.decrypted
= True
618 piece
.gpg_data
.sigs
= sigs
620 piece
.gpg_data
.plainobj
= parse_pgp_mime(plaintext_b
, gpgme_ctx
)
623 # if not encrypted, check to see if this is an armored signature.
624 (plaintext_b
, sigs
, sigkey_missing
, key_cannot_encrypt
) = verify_sig_message(piece
.string
, gpgme_ctx
)
626 piece
.gpg_data
.sigkey_missing
= sigkey_missing
627 piece
.gpg_data
.key_cannot_encrypt
= key_cannot_encrypt
630 piece
.piece_type
= TxtType
.signature
631 piece
.gpg_data
.sigs
= sigs
633 piece
.gpg_data
.plainobj
= parse_pgp_mime(plaintext_b
, gpgme_ctx
)
635 elif piece
.piece_type
== TxtType
.pubkey
:
636 piece
.gpg_data
= GPGData()
638 (key_fps
, key_cannot_encrypt
) = add_gpg_key(piece
.string
, gpgme_ctx
)
640 piece
.gpg_data
.key_cannot_encrypt
= key_cannot_encrypt
643 piece
.gpg_data
.keys
= key_fps
645 elif piece
.piece_type
== TxtType
.detachedsig
:
646 piece
.gpg_data
= GPGData()
648 for prev
in prev_parts
:
649 (sig_fps
, sigkey_missing
, key_cannot_encrypt
) = verify_detached_signature(piece
.string
, prev
.payload_bytes
, gpgme_ctx
)
651 piece
.gpg_data
.sigkey_missing
= sigkey_missing
652 piece
.gpg_data
.key_cannot_encrypt
= key_cannot_encrypt
655 piece
.gpg_data
.sigs
= sig_fps
656 piece
.gpg_data
.plainobj
= prev
663 def prepare_for_reply (eddymsg_obj
, replyinfo_obj
):
664 """Updates replyinfo_obj with info on the message's GPG success/failures
666 This function marks replyinfo_obj with information about whether encrypted
667 text in eddymsg_obj was successfully decrypted, signatures were verified
668 and whether a public key was found or not.
671 eddymsg_obj: a message in the EddyMsg format
672 replyinfo_obj: an instance of ReplyInfo
678 eddymsg_obj has had its gpg_data created by gpg_on_payloads
681 replyinfo_obj has been updated with info about decryption/sig
682 verififcation status, etc. However the desired key isn't imported until
683 later, so the success or failure of that updates the values set here.
686 do_to_eddys_pieces(prepare_for_reply_pieces
, eddymsg_obj
, replyinfo_obj
)
688 def prepare_for_reply_pieces (eddymsg_obj
, replyinfo_obj
):
689 """A helper function for prepare_for_reply
691 It updates replyinfo_obj with GPG success/failure information, when
692 supplied a single-part EddyMsg object.
695 eddymsg_obj: a single-part message in the EddyMsg format
696 replyinfo_obj: an object which holds information about the message's
703 eddymsg_obj is a single-part message. (it may be a part of a multi-part
704 message.) It has had its gpg_data created by gpg_on_payloads if it has
708 replyinfo_obj has been updated with gpg success/failure information
711 for piece
in eddymsg_obj
.payload_pieces
:
712 if piece
.piece_type
== TxtType
.text
:
713 # don't quote the plaintext part.
716 elif piece
.piece_type
== TxtType
.message
:
717 prepare_for_reply_message(piece
, replyinfo_obj
)
719 elif piece
.piece_type
== TxtType
.pubkey
:
720 prepare_for_reply_pubkey(piece
, replyinfo_obj
)
722 elif (piece
.piece_type
== TxtType
.detachedsig
) \
723 or (piece
.piece_type
== TxtType
.signature
):
724 prepare_for_reply_sig(piece
, replyinfo_obj
)
727 def prepare_for_reply_message (piece
, replyinfo_obj
):
728 """Helper function for prepare_for_reply()
730 This function is called when the piece_type of a payload piece is
731 TxtType.message, or GPG Message block. This should be encrypted text. If
732 the encryted block is correclty signed, a sig will be attached to
733 .target_key unless there is already one there.
736 piece: a PayloadPiece object.
737 replyinfo_obj: object which gets updated with decryption status, etc.
743 the piece.payload_piece value should be TxtType.message.
746 replyinfo_obj gets updated with decryption status, signing status, a
747 potential signing key, posession status of the public key for the
748 signature and encryption capability status if that key is missing.
751 if piece
.gpg_data
.plainobj
== None:
752 replyinfo_obj
.decrypt_failure
= True
755 replyinfo_obj
.decrypt_success
= True
757 # we already have a key (and a message)
758 if replyinfo_obj
.target_key
!= None:
761 if piece
.gpg_data
.sigs
== []:
762 if piece
.gpg_data
.sigkey_missing
== True:
763 replyinfo_obj
.sigkey_missing
= True
765 if piece
.gpg_data
.key_cannot_encrypt
== True:
766 replyinfo_obj
.key_cannot_encrypt
= True
768 # only include a signed message in the reply.
769 get_signed_part
= True
772 replyinfo_obj
.target_key
= piece
.gpg_data
.sigs
[0]
773 replyinfo_obj
.sig_success
= True
774 get_signed_part
= False
776 flatten_decrypted_payloads(piece
.gpg_data
.plainobj
, replyinfo_obj
, get_signed_part
)
778 # to catch public keys in encrypted blocks
779 prepare_for_reply(piece
.gpg_data
.plainobj
, replyinfo_obj
)
782 def prepare_for_reply_pubkey (piece
, replyinfo_obj
):
783 """Helper function for prepare_for_reply(). Marks pubkey import status.
785 Marks replyinfo_obj with pub key import status.
788 piece: a PayloadPiece object
789 replyinfo_obj: a ReplyInfo object
792 piece.piece_type should be set to TxtType.pubkey .
795 replyinfo_obj has its fields updated.
798 if piece
.gpg_data
.keys
== []:
799 if piece
.gpg_data
.key_cannot_encrypt
== True:
800 replyinfo_obj
.key_cannot_encrypt
= True
802 replyinfo_obj
.pubkey_success
= True
804 # prefer public key as a fallback for the encrypted reply
805 replyinfo_obj
.fallback_target_key
= piece
.gpg_data
.keys
[0]
808 def prepare_for_reply_sig (piece
, replyinfo_obj
):
809 """Helper function for prepare_for_reply(). Marks sig verification status.
811 Marks replyinfo_obj with signature verification status.
814 piece: a PayloadPiece object
815 replyinfo_obj: a ReplyInfo object
818 piece.piece_type should be set to TxtType.signature, or
819 TxtType.detachedsig .
822 replyinfo_obj has its fields updated.
825 if piece
.gpg_data
.sigs
== []:
826 replyinfo_obj
.sig_failure
= True
828 if piece
.gpg_data
.sigkey_missing
== True:
829 replyinfo_obj
.sigkey_missing
= True
831 if piece
.gpg_data
.key_cannot_encrypt
== True:
832 replyinfo_obj
.key_cannot_encrypt
= True
835 replyinfo_obj
.sig_success
= True
837 if replyinfo_obj
.fallback_target_key
== None:
838 replyinfo_obj
.fallback_target_key
= piece
.gpg_data
.sigs
[0]
840 if (piece
.piece_type
== TxtType
.signature
):
841 # to catch public keys in signature blocks
842 prepare_for_reply(piece
.gpg_data
.plainobj
, replyinfo_obj
)
845 def flatten_decrypted_payloads (eddymsg_obj
, replyinfo_obj
, get_signed_part
):
846 """For creating a string representation of a signed, encrypted part.
848 When given a decrypted payload, it will add either the plaintext or signed
849 plaintext to the reply message, depeding on 'get_signed_part'. This is
850 useful for ensuring that the reply message only comes from a signed and
851 ecrypted GPG message. It also sets the target_key for encrypting the reply
852 if it's told to get signed text only.
855 eddymsg_obj: the message in EddyMsg format created by decrypting GPG
857 replyinfo_obj: a ReplyInfo object for holding the message to quote and
858 the target_key to encrypt to.
859 get_signed_part: True if we should only include text that contains a
860 further signature. If False, then include plain text.
866 The EddyMsg instance passed in should be a piece.gpg_data.plainobj
867 which represents decrypted text. It may or may not be signed on that
871 the ReplyInfo instance may have a new 'target_key' set and its
872 'msg_to_quote' will be updated with (possibly signed) plaintext, if any
876 if eddymsg_obj
== None:
879 # recurse on multi-part mime
880 if eddymsg_obj
.multipart
== True:
881 for sub
in eddymsg_obj
.subparts
:
882 flatten_decrypted_payloads(sub
, replyinfo_obj
, get_signed_part
)
884 for piece
in eddymsg_obj
.payload_pieces
:
885 if (get_signed_part
):
886 if ((piece
.piece_type
== TxtType
.detachedsig
) \
887 or (piece
.piece_type
== TxtType
.signature
)) \
888 and (piece
.gpg_data
!= None) \
889 and (piece
.gpg_data
.plainobj
!= None):
890 flatten_decrypted_payloads(piece
.gpg_data
.plainobj
, replyinfo_obj
, False)
891 replyinfo_obj
.target_key
= piece
.gpg_data
.sigs
[0]
894 if (eddymsg_obj
.content_disposition
== None \
895 or not eddymsg_obj
.content_disposition
.startswith("attachment")) \
896 and piece
.piece_type
== TxtType
.text
:
897 replyinfo_obj
.msg_to_quote
+= piece
.string
900 def get_key_from_fp (replyinfo_obj
, gpgme_ctx
):
901 """Obtains a public key object from a key fingerprint
903 If the .target_key is not set, then we use .fallback_target_key, if
907 replyinfo_obj: ReplyInfo instance
908 gpgme_ctx: the gpgme context
914 Loading a key requires that we have the public key imported. This
915 requires that they email contains the pub key block, or that it was
916 previously sent to edward.
919 If the key can be loaded, then replyinfo_obj.reply_to_key points to the
920 public key object. If the key cannot be loaded, then the replyinfo_obj
921 is marked as having no public key available. If the key is not capable
922 of encryption, it will not be used, and replyinfo_obj will be marked
926 for key
in (replyinfo_obj
.target_key
, replyinfo_obj
.fallback_target_key
):
929 encrypt_to_key
= gpgme_ctx
.get_key(key
)
931 except gpgme
.GpgmeError
:
934 if is_key_usable(encrypt_to_key
):
935 replyinfo_obj
.encrypt_to_key
= encrypt_to_key
936 replyinfo_obj
.have_reply_key
= True
937 replyinfo_obj
.key_can_encrypt
= True
941 replyinfo_obj
.key_cannot_encrypt
= True
945 def write_reply (replyinfo_obj
):
946 """Write the reply email body about the GPG successes/failures.
948 The reply is about whether decryption, sig verification and key
949 import/loading was successful or failed. If text was successfully decrypted
950 and verified, then the first instance of such text will be included in
954 replyinfo_obj: contains details of GPG processing status
957 the plaintext message to be sent to the user
960 replyinfo_obj should be populated with info about GPG processing status.
965 if (replyinfo_obj
.pubkey_success
== True):
966 reply_plain
+= replyinfo_obj
.replies
['greeting']
967 reply_plain
+= "\n\n"
970 if replyinfo_obj
.decrypt_success
== True:
971 debug('decrypt success')
972 reply_plain
+= replyinfo_obj
.replies
['success_decrypt']
974 if (replyinfo_obj
.sig_success
== True) and (replyinfo_obj
.have_reply_key
== True):
975 debug('message quoted')
976 reply_plain
+= replyinfo_obj
.replies
['space']
977 reply_plain
+= replyinfo_obj
.replies
['quote_follows']
978 reply_plain
+= "\n\n"
979 quoted_text
= email_quote_text(replyinfo_obj
.msg_to_quote
)
980 reply_plain
+= quoted_text
982 reply_plain
+= "\n\n"
984 elif replyinfo_obj
.decrypt_failure
== True:
985 debug('decrypt failure')
986 reply_plain
+= replyinfo_obj
.replies
['failed_decrypt']
987 reply_plain
+= "\n\n"
990 if replyinfo_obj
.sig_success
== True:
991 debug('signature success')
992 reply_plain
+= replyinfo_obj
.replies
['sig_success']
993 reply_plain
+= "\n\n"
995 elif replyinfo_obj
.sig_failure
== True:
996 debug('signature failure')
997 reply_plain
+= replyinfo_obj
.replies
['sig_failure']
998 reply_plain
+= "\n\n"
1001 if (replyinfo_obj
.pubkey_success
== True):
1002 debug('public key received')
1003 reply_plain
+= replyinfo_obj
.replies
['public_key_received']
1004 reply_plain
+= "\n\n"
1006 elif (replyinfo_obj
.sigkey_missing
== True):
1007 debug('no public key')
1008 reply_plain
+= replyinfo_obj
.replies
['no_public_key']
1009 reply_plain
+= "\n\n"
1011 elif (replyinfo_obj
.key_can_encrypt
== False) \
1012 and (replyinfo_obj
.key_cannot_encrypt
== True):
1013 debug('bad public key')
1014 reply_plain
+= replyinfo_obj
.replies
['no_public_key']
1015 reply_plain
+= "\n\n"
1018 if (reply_plain
== ""):
1019 debug('plaintext message')
1020 reply_plain
+= replyinfo_obj
.replies
['failed_decrypt']
1021 reply_plain
+= "\n\n"
1024 reply_plain
+= replyinfo_obj
.replies
['signature']
1025 reply_plain
+= "\n\n"
1030 def add_gpg_key (key_block
, gpgme_ctx
):
1031 """Adds a GPG pubkey to the local keystore
1033 This adds keys received through email into the key store so they can be
1037 key_block: the string form of the ascii-armored public key block
1038 gpgme_ctx: the gpgme context
1041 the fingerprint(s) of the imported key(s) which can be used for
1042 encryption, and a boolean marking whether none of the keys are capable
1046 fp
= io
.BytesIO(key_block
.encode('ascii'))
1049 result
= gpgme_ctx
.import_(fp
)
1050 imports
= result
.imports
1051 except gpgme
.GpgmeError
:
1054 key_fingerprints
= []
1055 key_cannot_encrypt
= False
1057 for import_res
in imports
:
1058 fingerprint
= import_res
[0]
1061 key_obj
= gpgme_ctx
.get_key(fingerprint
)
1065 if key_obj
!= None and is_key_usable(key_obj
):
1066 key_fingerprints
+= [fingerprint
]
1067 key_cannot_encrypt
= False
1069 debug("added gpg key: " + fingerprint
)
1071 elif key_fingerprints
== []:
1072 key_cannot_encrypt
= True
1074 return (key_fingerprints
, key_cannot_encrypt
)
1077 def verify_sig_message (msg_block
, gpgme_ctx
):
1078 """Verifies the signature of a signed, ascii-armored block of text.
1080 It encodes the string into ascii, since binary GPG files are currently
1081 unsupported, and alternative, the ascii-armored format is encodable into
1085 msg_block: a GPG Message block in string form. It may be encrypted or
1086 not. If it is encrypted, it will return empty results.
1087 gpgme_ctx: the gpgme context
1090 A tuple containing the plaintext bytes of the signed part, the list of
1091 fingerprints of encryption-capable keys signing the data, a boolean
1092 marking whether edward is missing all public keys for validating any of
1093 the signatures, and a boolean marking whether all sigs' keys are
1094 incapable of encryption. If verification failed, perhaps because the
1095 message was also encrypted, sensible default values are returned.
1098 block_b
= io
.BytesIO(msg_block
.encode('ascii'))
1099 plain_b
= io
.BytesIO()
1102 sigs
= gpgme_ctx
.verify(block_b
, None, plain_b
)
1103 except gpgme
.GpgmeError
:
1104 return ("",[],False,False)
1106 plaintext_b
= plain_b
.getvalue()
1108 (fingerprints
, sigkey_missing
, key_cannot_encrypt
) = get_signature_fp(sigs
, gpgme_ctx
)
1110 return (plaintext_b
, fingerprints
, sigkey_missing
, key_cannot_encrypt
)
1113 def verify_detached_signature (detached_sig
, plaintext_bytes
, gpgme_ctx
):
1114 """Verifies the signature of a detached signature.
1116 This requires the signature part and the signed part as separate arguments.
1119 detached_sig: the signature part of the detached signature
1120 plaintext_bytes: the byte form of the message being signed.
1121 gpgme_ctx: the gpgme context
1124 A tuple containging a list of encryption capable signing fingerprints
1125 if the signature verification was sucessful, a boolean marking whether
1126 edward is missing all public keys for validating any of the signatures,
1127 and a boolean marking whether all signing keys are incapable of
1128 encryption. Otherwise, a tuple containing an empty list and True are
1132 detached_sig_fp
= io
.BytesIO(detached_sig
.encode('ascii'))
1133 plaintext_fp
= io
.BytesIO(plaintext_bytes
)
1136 sigs
= gpgme_ctx
.verify(detached_sig_fp
, plaintext_fp
, None)
1137 except gpgme
.GpgmeError
:
1138 return ([],False,False)
1140 (fingerprints
, sigkey_missing
, key_cannot_encrypt
) = get_signature_fp(sigs
, gpgme_ctx
)
1142 return (fingerprints
, sigkey_missing
, key_cannot_encrypt
)
1145 def decrypt_block (msg_block
, gpgme_ctx
):
1146 """Decrypts a block of GPG text and verifies any included sigatures.
1148 Some encypted messages have embeded signatures, so those are verified too.
1151 msg_block: the encrypted(/signed) text
1152 gpgme_ctx: the gpgme context
1155 A tuple containing plaintext bytes, encryption-capable signatures (if
1156 decryption and signature verification were successful, respectively), a
1157 boolean marking whether edward is missing all public keys for
1158 validating any of the signatures, and a boolean marking whether all
1159 signature keys are incapable of encryption.
1162 block_b
= io
.BytesIO(msg_block
.encode('ascii'))
1163 plain_b
= io
.BytesIO()
1166 sigs
= gpgme_ctx
.decrypt_verify(block_b
, plain_b
)
1167 except gpgme
.GpgmeError
:
1168 return ("",[],False,False)
1170 plaintext_b
= plain_b
.getvalue()
1172 (fingerprints
, sigkey_missing
, key_cannot_encrypt
) = get_signature_fp(sigs
, gpgme_ctx
)
1174 return (plaintext_b
, fingerprints
, sigkey_missing
, key_cannot_encrypt
)
1177 def get_signature_fp (sigs
, gpgme_ctx
):
1178 """Selects valid signatures from output of gpgme signature verifying functions
1180 get_signature_fp returns a list of valid signature fingerprints if those
1181 fingerprints are associated with available keys capable of encryption.
1184 sigs: a signature verification result object list
1185 gpgme_ctx: a gpgme context
1188 fingerprints: a list of fingerprints
1189 sigkey_missing: a boolean marking whether public keys are missing for
1190 all available signatures.
1191 key_cannot_encrypt: a boolearn marking whether available public keys are
1192 incapable of encryption.
1195 sigkey_missing
= False
1196 key_cannot_encrypt
= False
1200 if (sig
.summary
== 0) or (sig
.summary
& gpgme
.SIGSUM_VALID
!= 0) or (sig
.summary
& gpgme
.SIGSUM_GREEN
!= 0):
1202 key_obj
= gpgme_ctx
.get_key(sig
.fpr
)
1204 if fingerprints
== []:
1205 sigkey_missing
= True
1208 if is_key_usable(key_obj
):
1209 fingerprints
+= [sig
.fpr
]
1210 key_cannot_encrypt
= False
1211 sigkey_missing
= False
1213 elif fingerprints
== []:
1214 key_cannot_encrypt
= True
1216 elif fingerprints
== []:
1217 if (sig
.summary
& gpgme
.SIGSUM_KEY_MISSING
!= 0):
1218 sigkey_missing
= True
1220 return (fingerprints
, sigkey_missing
, key_cannot_encrypt
)
1223 def is_key_usable (key_obj
):
1224 """Returns boolean representing key usability regarding encryption
1226 Tests various feature of key and returns usability
1229 key_obj: a gpgme key object
1232 A boolean representing key usability
1234 if key_obj
.can_encrypt
and not key_obj
.invalid
and not key_obj
.expired \
1235 and not key_obj
.revoked
and not key_obj
.disabled
:
1241 def email_to_reply_to_subject (email_bytes
):
1242 """Returns the email's To:, Reply-To: (or From:), and Subject: fields
1244 Returns this information from an email.
1247 email_bytes: the byte string form of the email
1250 the email To:, Reply-To: (or From:), and Subject: fields as strings
1253 email_struct
= email
.parser
.BytesHeaderParser().parsebytes(email_bytes
)
1255 email_to
= email_struct
['To']
1256 email_from
= email_struct
['From']
1257 email_reply_to
= email_struct
['Reply-To']
1259 email_subject
= email_struct
['Subject']
1261 if email_reply_to
== None:
1262 email_reply_to
= email_from
1264 return email_to
, email_reply_to
, email_subject
1267 def import_lang_pick_address(email_to
, hostname
):
1268 """Imports language file for i18n support; makes reply from address
1270 The language imported depends on the To: address of the email received by
1271 edward. an -en ending implies the English language, whereas a -ja ending
1272 implies Japanese. The list of supported languages is listed in the 'langs'
1273 list at the beginning of the program. This function also chooses the
1274 language-dependent address which can be used as the From address in the
1278 email_to: the string containing the email address that the mail was
1280 hostname: the hostname part of the reply email's from address
1283 the reference to the imported language module. The only variable in
1284 this file is the 'replies' dictionary.
1290 if email_to
!= None:
1292 if "edward-" + lang
in email_to
:
1296 lang_mod_name
= "lang." + re
.sub('-', '_', use_lang
)
1297 lang_module
= importlib
.import_module(lang_mod_name
)
1299 reply_from
= "edward-" + use_lang
+ "@" + hostname
1301 return lang_module
, reply_from
1304 def generate_encrypted_mime (plaintext
, email_to
, email_subject
, encrypt_to_key
,
1306 """This function creates the mime email reply. It can encrypt the email.
1308 If the encrypt_key is included, then the email is encrypted and signed.
1309 Otherwise it is unencrypted.
1312 plaintext: the plaintext body of the message to create.
1313 email_to: the email address to reply to
1314 email_subject: the subject to use in reply
1315 encrypt_to_key: the key object to use for encrypting the email. (or
1317 gpgme_ctx: the gpgme context
1320 A string version of the mime message, possibly encrypted and signed.
1323 plaintext_mime
= MIMEText(plaintext
)
1324 plaintext_mime
.set_charset('utf-8')
1326 if (encrypt_to_key
!= None):
1328 encrypted_text
= encrypt_sign_message(plaintext_mime
.as_string(),
1332 control_mime
= MIMEApplication("Version: 1",
1333 _subtype
='pgp-encrypted',
1334 _encoder
=email
.encoders
.encode_7or8bit
)
1335 control_mime
['Content-Description'] = 'PGP/MIME version identification'
1336 control_mime
.set_charset('us-ascii')
1338 encoded_mime
= MIMEApplication(encrypted_text
,
1339 _subtype
='octet-stream; name="encrypted.asc"',
1340 _encoder
=email
.encoders
.encode_7or8bit
)
1341 encoded_mime
['Content-Description'] = 'OpenPGP encrypted message'
1342 encoded_mime
['Content-Disposition'] = 'inline; filename="encrypted.asc"'
1343 encoded_mime
.set_charset('us-ascii')
1345 message_mime
= MIMEMultipart(_subtype
="encrypted", protocol
="application/pgp-encrypted")
1346 message_mime
.attach(control_mime
)
1347 message_mime
.attach(encoded_mime
)
1348 message_mime
['Content-Disposition'] = 'inline'
1351 message_mime
= plaintext_mime
1353 message_mime
['To'] = email_to
1354 message_mime
['Subject'] = email_subject
1356 reply
= message_mime
.as_string()
1361 def send_reply(email_txt
, reply_to
, reply_from
):
1362 """Sends reply email
1364 Sent to original sender
1367 email_txt: message as a string
1368 reply_to: recipient of reply
1369 reply_from: edward's specific email address
1375 if reply_to
== None:
1376 error("*** ERROR: No one to send email to.")
1379 s
= smtplib
.SMTP('localhost')
1380 s
.sendmail(reply_from
, reply_to
, email_txt
)
1384 def email_quote_text (text
):
1385 """Quotes input text by inserting "> "s
1387 This is useful for quoting a text for the reply message. It inserts "> "
1388 strings at the beginning of lines.
1391 text: plain text to quote
1397 quoted_message
= re
.sub(r
'^', r
'> ', text
, flags
=re
.MULTILINE
)
1399 return quoted_message
1402 def encrypt_sign_message (plaintext
, encrypt_to_key
, gpgme_ctx
):
1403 """Encrypts and signs plaintext
1405 This encrypts and signs a message.
1408 plaintext: text to sign and ecrypt
1409 encrypt_to_key: the key object to encrypt to
1410 gpgme_ctx: the gpgme context
1413 An encrypted and signed string of text
1416 # the plaintext should be mime encoded in an ascii-compatible form
1417 plaintext_bytes
= io
.BytesIO(plaintext
.encode('ascii'))
1418 encrypted_bytes
= io
.BytesIO()
1420 gpgme_ctx
.encrypt_sign([encrypt_to_key
], gpgme
.ENCRYPT_ALWAYS_TRUST
,
1421 plaintext_bytes
, encrypted_bytes
)
1423 encrypted_txt
= encrypted_bytes
.getvalue().decode('ascii')
1424 return encrypted_txt
1427 def error (error_msg
):
1428 """Write an error message to stdout
1430 The error message includes the program name.
1433 error_msg: the message to print
1439 An error message is printed to stdout
1442 sys
.stderr
.write(progname
+ ": " + str(error_msg
) + "\n")
1445 def debug (debug_msg
):
1446 """Writes a debug message to stdout if debug == True
1448 If the debug option is set in edward_config.py, then the passed message
1449 gets printed to stdout.
1452 debug_msg: the message to print to stdout
1458 A debug message is printed to stdout
1461 if edward_config
.debug
== True:
1466 """Sets the progname variable and processes optional argument
1468 If there are more than two arguments then edward complains and quits. An
1469 single "-p" argument sets the print_reply_only option, which makes edward
1470 print email replies instead of mailing them.
1476 True if edward should print arguments instead of mailing them,
1477 otherwise it returns False.
1480 Exits with error 1 if there are more than two arguments, otherwise
1481 returns the print_reply_only option.
1485 progname
= sys
.argv
[0]
1487 print_reply_only
= False
1489 if len(sys
.argv
) > 2:
1490 print(progname
+ " usage: " + progname
+ " [-p]\n\n" \
1491 + " -p print reply message to stdout, do not mail it\n", \
1495 elif (len(sys
.argv
) == 2) and (sys
.argv
[1] == "-p"):
1496 print_reply_only
= True
1498 return print_reply_only
1501 if __name__
== "__main__":
1502 """Executes main if this file is not loaded interactively"""