diff options
| -rw-r--r-- | _spacemacs.d/config/my-crypt.el | 33 | ||||
| -rw-r--r-- | _spacemacs.d/local/jl-encrypt.el | 433 |
2 files changed, 466 insertions, 0 deletions
diff --git a/_spacemacs.d/config/my-crypt.el b/_spacemacs.d/config/my-crypt.el new file mode 100644 index 0000000..1720f8f --- /dev/null +++ b/_spacemacs.d/config/my-crypt.el @@ -0,0 +1,33 @@ +;;; my-crypt.el --- Custom sign/encrypt configurations +;; -*- mode: emacs-lisp -*- +;; vim: set ts=8 sw=2 tw=0 fenc=utf-8 ft=lisp: +;; +;; Aaron LI +;; Created: 2017-10-15 +;; + +;;; Commentary: +;; Custom sign/encrypt configurations +;; + +;;; Code: + +;; Default Encrypt +;; https://www.emacswiki.org/emacs/DefaultEncrypt +;; https://www.emacswiki.org/emacs/download/jl-encrypt.el +(require 'jl-encrypt) + +;; Ask for the signing key +(setq mm-sign-option 'guided) + +;; Use message sender to find the OpenPGP key to sign with +(setq mml-secure-openpgp-sign-with-sender t) + +;; Also encrypt to the message sender, otherwise, the send message +;; *cannot* be decrypted by the sender! +(setq mml-secure-openpgp-encrypt-to-self t) + + +(provide 'my-crypt) + +;;; my-crypt.el ends here diff --git a/_spacemacs.d/local/jl-encrypt.el b/_spacemacs.d/local/jl-encrypt.el new file mode 100644 index 0000000..991139f --- /dev/null +++ b/_spacemacs.d/local/jl-encrypt.el @@ -0,0 +1,433 @@ +;;; jl-encrypt.el --- Insert MML encryption tags if public keys are available +;; -*- Mode: Emacs-Lisp -*- +;; -*- coding: utf-8 -*- + +;; Copyright (C) 2011, 2012, 2013, 2014, 2016 Jens Lechtenbörger +;; Copyright (C) 2013 konubinix + +;; Changelog: +;; 2012/03/09, Version 1.1, initial release +;; 2013/03/18, Version 2.1, integrate patch by konubinix to also encrypt +;; e-mail that already contains a secure sign tag: +;; - Add functions jl-is-signed-p and jl-do-not-sign-p. +;; - Change jl-secure-message-gpg and jl-secure-message-smime to use +;; jl-do-not-sign-p (and not only jl-encrypt-without-signature). +;; - Change jl-message-send-maybe-exit to look for secure encrypt tag +;; (instead of any secure tag). +;; - Add Changelog, give credit to konubinix +;; 2013/07/01, Version 3.1, support XEmacs, don't break news, don't replace +;; S/MIME tag with GnuPG tag if possible. New version started based on +;; feedback and testing by Michael Strauss. +;; - Replace delete-dups with mm-delete-duplicates as XEmacs does not have +;; delete-dups. +;; - Bug fixed when rebinding keys: Use (interactive "P") instead of +;; (interactive "p"). +;; - Do not attempt to encrypt news postings, only go for e-mails with +;; non-empty recipient lists. +;; - If the user inserted an S/MIME signature tag, and S/MIME as well as +;; GnuPG keys are available, don't prefer GnuPG any more but upgrade +;; S/MIME signature to S/MIME sign+encrypt. +;; - Refactoring. +;; - Added jl-method-table, jl-access-method-table, jl-mail-recipients, +;; jl-maybe-add-tag, jl-maybe-add-tag-for-args, jl-is-smime-p. +;; - Based on above, simplified jl-proceed-without-encryption-p and +;; jl-encrypt-if-possible. +;; - Moved jl-certfile-available-p and jl-secure-message-smime to +;; jl-smime. +;; - Explain potential unsafety of Bcc headers. Safety check added. +;; Added jl-encrypt-safe-bcc-list. +;; - Changed jl-gpgkey-available-p to produce less false positives. +;; - Replaced jl-encrypt-without-signature with jl-encrypt-insert-signature. +;; Have jl-encrypt-if-possible use it. Bug fix in jl-is-signed-p. +;; - Different treatment of From header. See comment for new variable +;; jl-encrypt-ignore-from. +;; - Simplified internal recipient lists now contain just lower-case e-mail +;; addresses (no names any longer). +;; - Use defcustom instead of defvar for user variables, which are also +;; renamed. +;; 2013/12/20, Version 4-beta, unified use of EasyPG for gpg and gpgsm. +;; - Removed variables jl-encrypt-ignore-from and +;; jl-encrypt-recipient-headers. +;; Treatment of encryption targets now controlled entirely by EasyPG +;; (and GnuPG configuration files). New functions jl-epg-find-usable-keys +;; and jl-epg-check-unique-keys towards that end. +;; - New variable jl-encrypt-manual-choice. +;; If several public keys are available for a recipient, ask user which +;; one to use. (Requires `mm-encrypt-option' introduced in Emacs 23.2.) +;; 2013/12/31, Version 4.1. +;; - Take care of interface change for mml2015-epg-find-usable-key +;; starting with Ma Gnus v0.7. +;; - Updated documentation. +;; 2014/09/16, Version 4.2. +;; - No change in functionality. +;; - Use message-send-hook instead of key rebinding. +;; - Replaced jl-encrypt-manual-choice with +;; jl-encrypt-i-am-aware-of-mm-encrypt-option. +;; - Renamed jl-mail-recipients to jl-message-recipients and +;; jl-encrypt-address-list to jl-message-address-list. +;; 2016/03/28, Version 4.3. +;; - No change in functionality. +;; - Adapted for Emacs 25.1. + +;; Compatibility: GNU Emacs 25.1 + +;; This program is free software; you can redistribute it and/or +;; modify it under the terms of the GNU General Public License as +;; published by the Free Software Foundation; either version 3, or +;; (at your option) any later version. + +;; This program is distributed in the hope that it will be useful, +;; but WITHOUT ANY WARRANTY; without even the implied warranty of +;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +;; General Public License for more details. + +;; You should have received a copy of the GNU General Public License +;; along with GNU Emacs; see the file COPYING. +;; If not, see http://www.gnu.org/licenses/ or write to the +;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, +;; Boston, MA 02110-1301, USA. + +;; Keywords: mail, encryption, GnuPG, gpg, OpenPGP, gpgsm, S/MIME, CMS + +;; URL: http://www.emacswiki.org/emacs/jl-encrypt.el +;; EmacsWiki: DefaultEncrypt + +;; A signed version of this file is available over there: +;; http://www.informationelle-selbstbestimmung-im-internet.de/emacs/ + +;;; Commentary: +;; Gnus supports GnuPG via the insertion of so-called MML secure tags, which +;; contain encryption instructions to be performed before a message is sent. +;; However, by default those tags need to be added manually, which can easily +;; be forgotten. In contrast, DefaultEncrypt aims to insert those tags +;; automatically if public keys for all recipients are available. +;; +;; I assume that you are familiar with GnuPG support for Gnus messages as +;; described in Info node `(message) Security': +;; https://www.gnu.org/software/emacs/manual/html_node/message/Security.html +;; Moreover, DefaultEncrypt is based on EasyPG, the default interface of +;; Emacs for OpenPGP and S/MIME, see Info node `(epa)': +;; https://www.gnu.org/software/emacs/manual/html_node/epa/index.html +;; +;; DefaultEncrypt aims for automatic insertion of an MML secure encryption +;; tags into messages if public keys (either GnuPG public keys or S/MIME +;; certificates) for all recipients are available. In addition, before a +;; message is sent, the user is asked whether plaintext should really be sent +;; unencryptedly when public keys for all recipients are available. +;; +;; The above works by adding +;; `mml-secure-encrypt-if-possible' to `gnus-message-setup-hook' and +;; `mml-secure-check-encryption-p' to `message-send-hook'. +;; +;; Note that with EasyPG, e-mail is *not* encrypted to (a key for) the +;; From address (see Info node `(epa) Mail-mode integration'). +;; Instead, to make sure that you can decrypt your own e-mails, typical +;; options are +;; * to customize mml-secure-openpgp-encrypt-to-self or +;; * to use a Bcc header to encrypt the e-mail to one of your own +;; GnuPG identities (see `mml-secure-safe-bcc-list' then) or +;; * to use the encrypt-to or hidden-encrypt-to option in gpg.conf or +;; * to use the encrypt-to option in gpgsm.conf. +;; Note that encrypt-to gives away your identity for *every* +;; encryption without warning, which is not what you want if you are +;; using, e.g., remailers. +;; Also, be careful with Bcc headers; it *might* be possible to make +;; this work without giving away the Bcc'ed identities, but it did +;; not work by default in my case, and I recommend against such a +;; thing: Only add Bcc if you are absolutely sure that you know what +;; you are doing. See also `mml-secure-bcc-is-safe'. +;; +;; If you are interested in S/MIME then I suggest that you read this: +;; https://blogs.fsfe.org/jens.lechtenboerger/2013/12/23/openpgp-and-smime/ +;; If you are still interested in S/MIME afterwards, take a look +;; at ExtendSMIME (jl-smime.el) in addition to this file. + +;; Install: +;; Place this file into your load-path and add the following to ~/.emacs. +;; (require 'jl-encrypt) +;; If you share my preferences, no further configuration should be necessary. +;; +;; Customizable variables defined in this file are +;; `mml-secure-insert-signature', `mml-secure-pgp-without-mime'. +;; +;; In addition, as explained in the following `mml-default-encrypt-method' and +;; `mml-default-sign-method' influence whether to prefer S/MIME or GnuPG in +;; certain situations, and the value of `gnus-message-replysignencrypted' may +;; be changed by this code. +;; If `mml-secure-insert-signature' is nil (the default), +;; `gnus-message-replysignencrypted' will be set to nil to avoid signatures +;; for reply messages. You may manually add MML sign tags any time, of +;; course, but the whole point of this file is to create MML tags automatically +;; (e.g., by customizing `mml-secure-insert-signature'). +;; If GnuPG and S/MIME keys are both available for the given recipients and no +;; MML tag is present, `mml-default-encrypt-method' determines what method to +;; prefer. If `mml-secure-insert-signature' is set to `always', +;; `mml-default-sign-method' determines what method to prefer upon message +;; creation. + +;; Sanity check: +;; Without any further configuration, send a GnuPG encrypted e-mail to +;; yourself as follows. Enter your own e-mail address after To, choose some +;; Subject, and enter `M-x spook' in the body, which will insert suitable +;; text. Then press `C-c C-c' to send the e-mail as usual (forgetting to +;; encrypt). If you own a GnuPG public for the To e-mail address then you +;; will be asked whether you really want to send that e-mail as plaintext. +;; Answering `no' will insert an MML secure tag for you. Press `C-c C-c' +;; again, and an encrypted e-mail will be sent. If you receive that e-mail +;; with garbled attachments read the comment for +;; `mml-secure-pgp-without-mime'. + +;; You may want to check the subsequent comments to understand the rationale +;; of my changes to standard message behavior. + +;; This file is *NOT* part of GNU Emacs. + +;;; Code: +(require 'gnus) +(require 'message) +(require 'mml-sec) +(require 'epg) + +;; Make gnus insert MML encryption tags if keys for all recipients are +;; available. Thus, if you reply (or wide reply) to a message or edit +;; a saved draft, then MML encryption tags will be inserted right away. +;; Moreover, if mml-secure-insert-signature is always, an MML signature +;; tag will be added immediately. +(add-hook 'gnus-message-setup-hook 'mml-secure-encrypt-if-possible) +(add-hook 'message-send-hook 'mml-secure-check-encryption-p) + +(defgroup jl-encrypt nil + "Customization options for jl-encrypt.el.") + +(defcustom mml-secure-insert-signature nil + "Control whether MML signature tags should be produced. +If it is nil, no signatures are created. If it is `always', signature +tags are inserted for new messages (with their type determined by +`mml-default-sign-method'). If is is `encrypted', messages that are +encrypted are also signed." + :group 'jl-encrypt + :type '(choice (const nil) (const always) (const encrypted))) + +;; Note that mml-default-encrypt-method combines two separate concepts: First, +;; whether to use OpenPGP or S/MIME. Second, if OpenPGP is chosen whether to +;; use MIME Security or not. For me, this is not good enough. Suppose I +;; preferred S/MIME in general (which I do not). Then, I would need to +;; customize mml-default-encrypt-method for S/MIME. If I then send an e-mail +;; to someone who does not use S/MIME but OpenPGP, the variable +;; mml-default-encrypt-method does not help at all, and there is no way to +;; know whether MIME Security should be used or not. Thus, I introduce an +;; additional variable that focuses on MIME Security for OpenPGP: +(defcustom mml-secure-pgp-without-mime nil + "Non-nil to use MML encryption without MIME Security for OpenPGP. +RFC 3156 specifies how OpenPGP (and, thus, GnuPG) and MIME work +together. In Gnus, `mml-secure-message-encrypt-pgpmime' follows +that standard. An alternative is +`mml-secure-message-encrypt-pgp', which represents a less +powerful approach. If you (like me in the past) happen to send +e-mails in an environment using broken M$ SMTP servers, then your +beautiful e-mails produced by +`mml-secure-message-encrypt-pgpmime', following RFC 3156, will be +corrupted along the way. E.g., the SMTP server at my department +throws away the e-mail's Content-Type \"multipart/encrypted\" and +its \"protocol=application/pgp-encrypted\" and inserts a +meaningless \"multipart/mixed\" one. Thus, the recipient will +have a hard time figuring out what the e-mail's strange +attachments are good for. FUBAR. +If this variable is set to nil (the default) then your e-mails +are built according to RFC 3156. I suggest that you send an +encrypted e-mail to yourself. Complain to your IT department if +you receive garbled attachments. Then set this variable to +non-nil, while they are setting up a reasonable SMTP server. +If you are signing all your e-mails with GnuPG you probably also +want to set `mml-default-sign-method' to \"pgp\" (instead of +\"pgpmime\")." + :group 'jl-encrypt + :type 'boolean) + +;; +;; No configuration options beyond this point. Just code. +;; + +;; Message header functions. +;; Could go into message.el + +(defun jl-message-address-list (header) + "Return e-mail addresses of HEADER as list." + (let ((hdr (mail-strip-quoted-names (message-fetch-field header)))) + (when hdr + ;; Split recipients at "," boundary, omit empty strings (t), + ;; and strip whitespace. + (split-string hdr "," t "\\s-+")))) + +(defun jl-message-recipients () + "Return recipients of current message or nil. +Recipients are only returned if the message is an e-mail with at +least one recipient." + (if (message-mail-p) + (let ((recipients + (delete-dups + ;; Split recipients at "," boundary, omit empty strings (t), + ;; and strip whitespace. + (split-string (message-options-set-recipient) + "," t "\\s-+")))) + (if (>= (length recipients) 1) + recipients + nil)) + nil)) + + +;; epa functions. +;; Could go into mml-sec.el or a new file mml-epg.el. + +(defun mml-epg-gpgkey-available-p (recipient) + "Check whether EasyPG knows a public OpenPGP key for RECIPIENT." + (mml-secure-find-usable-keys + (epg-make-context 'OpenPGP) recipient 'encrypt t)) + + +;; MML functions. +;; Could go into mml-sec.el + +(defun mml-secure-message-gpg () + "Invoke MML function to add appropriate secure tag for GnuPG. +The choice between pgp or pgpmime is based on `mml-secure-pgp-without-mime'. +Creation of signatures is controlled by `mml-secure-do-not-sign-p'." + (if mml-secure-pgp-without-mime + (mml-secure-message-encrypt-pgp (mml-secure-do-not-sign-p)) + (mml-secure-message-encrypt-pgpmime (mml-secure-do-not-sign-p)))) + +(defun mml-secure-is-secure-p (string) + "Check whether secure tag containing STRING is present." + (save-excursion + (goto-char (point-min)) + (re-search-forward + (concat "^" (regexp-quote mail-header-separator) "\n" + "<#secure[^>]+" string) + nil t))) + +(defun mml-secure-is-encrypted-p () + "Check whether secure encrypt tag is present." + (mml-secure-is-secure-p "encrypt")) + +(defun mml-secure-is-smime-p () + "Check whether secure tag for S/MIME is present." + (mml-secure-is-secure-p "method=smime")) + +(defun mml-secure-is-signed-p () + "Check whether secure sign tag is present." + (mml-secure-is-secure-p "sign")) + +(defun mml-secure-do-not-sign-p () + "Check whether the message should not be signed. +This is the case if `mml-secure-insert-signature' is nil and +no secure sign tag is present." + (and (not mml-secure-insert-signature) + (not (mml-secure-is-signed-p)))) + +(defun mml-secure-encrypt-if-possible () + "Insert MML security tag if appropriate. +This function may insert MML tags for signing and/or encryption. +Creation of sign tags is controlled by `mml-secure-insert-signature'. If +that variable is `always', a sign tag for method `mml-default-sign-method' +is created. +Moreover, the creation of an encrypt tag is determined based on the existence +of public keys for all recipients of the current message, see +`mml-secure-maybe-add-tag'. If an encrypt tag is added, the message will +additionally be signed if `mml-secure-insert-signature' is `encrypted'." + (if (not mml-secure-insert-signature) + (setq gnus-message-replysignencrypted nil) + (if (eq 'always mml-secure-insert-signature) + (mml-secure-message mml-default-sign-method 'sign))) + (mml-secure-maybe-add-tag t)) + +(defun mml-secure-maybe-add-tag-for-args (recipients method &optional dontask) + "Maybe add MML secure tag for RECIPIENTS and METHOD. +If keys are available for all RECIPIENTS and METHOD and DONTASK is +nil, ask whether no encryption should be performed. If the user +answers \"yes\",don't add an MML tag and return `yes'; if the user +answers \"no\", insert tag and return `no'. +Otherwise, if DONTASK is t, insert tag and return 'inserted. +Otherwise, return `failed'." + (if (gnus-test-list recipients + (mml-secure-access-method-table method "test")) + (if (not dontask) + (if (yes-or-no-p (mml-secure-access-method-table method "ask")) + 'yes + (funcall (mml-secure-access-method-table method "doit")) + 'no) + (funcall (mml-secure-access-method-table method "doit")) + (message "Inserted %s tag" method) + 'inserted) + (message "Failed to insert %s tag" method) + 'failed)) + +(defun mml-secure-maybe-add-tag (&optional dontask) + "Maybe add MML secure encryption tag to current message. +If no recipients are returned by `jl-message-recipients', +immediately return `failed'. Otherwise, try to add a tag for +those recipients. If jl-smime.el has been loaded, S/MIME tags +may be inserted; otherwise only the default of GnuPG tags. +Which method is tried first if both are available depends on the +current message and the value of `mml-default-encrypt-method': If +`mml-default-encrypt-method' indicates S/MIME or if the message +carries an S/MIME signature tag, go for S/MIME first; otherwise +for GnuPG. Call `mml-secure-maybe-add-tag-for-args' with recipients, +chosen method, and DONTASK. +If that call does not return `failed', return this result. +Otherwise, re-try the call with the second method and return its +result." + (let ((recipients (jl-message-recipients))) + (if recipients + (let* ((smime-supported (assq 'CMS mml-secure-method-table)) + (is-smime (and smime-supported + (or (string= "smime" mml-default-encrypt-method) + (mml-secure-is-smime-p)))) + (first-method (if is-smime 'CMS 'OpenPGP)) + (second-method (if is-smime 'OpenPGP + (if smime-supported 'CMS))) + (first-result (mml-secure-maybe-add-tag-for-args + recipients first-method dontask))) + (if (and (eq 'failed first-result) second-method) + (mml-secure-maybe-add-tag-for-args + recipients second-method dontask) + first-result)) + 'failed))) + +(defun mml-secure-proceed-without-encryption-p (&optional dontask) + "Return t if no (additional) encryption is necessary. +This happens if `mml-secure-maybe-add-tag' called with DONTASK does +not return 'no. Otherwise, raise an error." + (if (not (eq 'no (mml-secure-maybe-add-tag dontask))) + t + (error "Encryption is a Good Thing."))) + +(defun mml-secure-check-encryption-p () + "Check whether MML secure encrypt tag is present or not appropriate. +If MML secure encrypt tag is not present, check via +`mml-secure-proceed-without-encryption-p' whether public keys for all +recipients are available and an MML secure tag should be added, or +whether the message should be sent without encryption. In the latter +case return t. Otherwise, raise an error." + (save-excursion + (or (mml-secure-is-encrypted-p) + (mml-secure-proceed-without-encryption-p)))) + +(defvar mml-secure-method-table '((OpenPGP + (("test" mml-epg-gpgkey-available-p) + ("doit" mml-secure-message-gpg) + ("ask" "GnuPG public keys available \ +for all recipients. Really proceed *without* encryption? ")))) + "Internal functionality for supported security methods.") + +(defun mml-secure-access-method-table (method what) + "Return object for METHOD representing WHAT." + (let ((method-spec (assq method mml-secure-method-table))) + (if method-spec + (cadr (assoc what (cadr method-spec))) + (if (eq method 'CMS) + (error "You must load jl-smime for S/MIME support") + (error + "Method `%s' not supported by `mml-secure-method-table'" method))))) + +(provide 'jl-encrypt) +;;; jl-encrypt.el ends here |