lisp/gnus/mml-sec.el

   1 ;;; mml-sec.el --- A package with security functions for MML documents
   2
   3 ;; Copyright (C) 2000-2015 Free Software Foundation, Inc.
   4
   5 ;; Author: Simon Josefsson <simon@josefsson.org>
   6
   7 ;; This file is part of GNU Emacs.
   8
   9 ;; GNU Emacs is free software: you can redistribute it and/or modify
  10 ;; it under the terms of the GNU General Public License as published by
  11 ;; the Free Software Foundation, either version 3 of the License, or
  12 ;; (at your option) any later version.
  13
  14 ;; GNU Emacs is distributed in the hope that it will be useful,
  15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 ;; GNU General Public License for more details.
  18
  19 ;; You should have received a copy of the GNU General Public License
  20 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  21
  22 ;;; Commentary:
  23
  24 ;;; Code:
  25
  26 (eval-when-compile (require 'cl))
  27
  28 (autoload 'mml2015-sign "mml2015")
  29 (autoload 'mml2015-encrypt "mml2015")
  30 (autoload 'mml1991-sign "mml1991")
  31 (autoload 'mml1991-encrypt "mml1991")
  32 (autoload 'message-goto-body "message")
  33 (autoload 'mml-insert-tag "mml")
  34 (autoload 'mml-smime-sign "mml-smime")
  35 (autoload 'mml-smime-encrypt "mml-smime")
  36 (autoload 'mml-smime-sign-query "mml-smime")
  37 (autoload 'mml-smime-encrypt-query "mml-smime")
  38 (autoload 'mml-smime-verify "mml-smime")
  39 (autoload 'mml-smime-verify-test "mml-smime")
  40
  41 (defvar mml-sign-alist
  42   '(("smime"     mml-smime-sign-buffer     mml-smime-sign-query)
  43     ("pgp"       mml-pgp-sign-buffer       list)
  44     ("pgpauto"   mml-pgpauto-sign-buffer  list)
  45     ("pgpmime"   mml-pgpmime-sign-buffer   list))
  46   "Alist of MIME signer functions.")
  47
  48 (defcustom mml-default-sign-method "pgpmime"
  49   "Default sign method.
  50 The string must have an entry in `mml-sign-alist'."
  51   :version "22.1"
  52   :type '(choice (const "smime")
  53                  (const "pgp")
  54                  (const "pgpauto")
  55                  (const "pgpmime")
  56                  string)
  57   :group 'message)
  58
  59 (defvar mml-encrypt-alist
  60   '(("smime"     mml-smime-encrypt-buffer     mml-smime-encrypt-query)
  61     ("pgp"       mml-pgp-encrypt-buffer       list)
  62     ("pgpauto"   mml-pgpauto-sign-buffer  list)
  63     ("pgpmime"   mml-pgpmime-encrypt-buffer   list))
  64   "Alist of MIME encryption functions.")
  65
  66 (defcustom mml-default-encrypt-method "pgpmime"
  67   "Default encryption method.
  68 The string must have an entry in `mml-encrypt-alist'."
  69   :version "22.1"
  70   :type '(choice (const "smime")
  71                  (const "pgp")
  72                  (const "pgpauto")
  73                  (const "pgpmime")
  74                  string)
  75   :group 'message)
  76
  77 (defcustom mml-signencrypt-style-alist
  78   '(("smime"   separate)
  79     ("pgp"     combined)
  80     ("pgpauto" combined)
  81     ("pgpmime" combined))
  82   "Alist specifying if `signencrypt' results in two separate operations or not.
  83 The first entry indicates the MML security type, valid entries include
  84 the strings \"smime\", \"pgp\", and \"pgpmime\".  The second entry is
  85 a symbol `separate' or `combined' where `separate' means that MML signs
  86 and encrypt messages in a two step process, and `combined' means that MML
  87 signs and encrypt the message in one step.
  88
  89 Note that the output generated by using a `combined' mode is NOT
  90 understood by all PGP implementations, in particular PGP version
  91 2 does not support it!  See Info node `(message)Security' for
  92 details."
  93   :version "22.1"
  94   :group 'message
  95   :type '(repeat (list (choice (const :tag "S/MIME" "smime")
  96                                (const :tag "PGP" "pgp")
  97                                (const :tag "PGP/MIME" "pgpmime")
  98                                (string :tag "User defined"))
  99                        (choice (const :tag "Separate" separate)
 100                                (const :tag "Combined" combined)))))
 101
 102 (defcustom mml-secure-verbose nil
 103   "If non-nil, ask the user about the current operation more verbosely."
 104   :group 'message
 105   :type 'boolean)
 106
 107 (defcustom mml-secure-cache-passphrase
 108   (if (boundp 'password-cache)
 109       password-cache
 110     t)
 111   "If t, cache passphrase."
 112   :group 'message
 113   :type 'boolean)
 114
 115 (defcustom mml-secure-passphrase-cache-expiry
 116   (if (boundp 'password-cache-expiry)
 117       password-cache-expiry
 118     16)
 119   "How many seconds the passphrase is cached.
 120 Whether the passphrase is cached at all is controlled by
 121 `mml-secure-cache-passphrase'."
 122   :group 'message
 123   :type 'integer)
 124
 125 ;;; Configuration/helper functions
 126
 127 (defun mml-signencrypt-style (method &optional style)
 128   "Function for setting/getting the signencrypt-style used.  Takes two
 129 arguments, the method (e.g. \"pgp\") and optionally the mode
 130 \(e.g. combined).  If the mode is omitted, the current value is returned.
 131
 132 For example, if you prefer to use combined sign & encrypt with
 133 smime, putting the following in your Gnus startup file will
 134 enable that behavior:
 135
 136 \(mml-set-signencrypt-style \"smime\" combined)
 137
 138 You can also customize or set `mml-signencrypt-style-alist' instead."
 139   (let ((style-item (assoc method mml-signencrypt-style-alist)))
 140     (if style-item
 141         (if (or (eq style 'separate)
 142                 (eq style 'combined))
 143             ;; valid style setting?
 144             (setf (second style-item) style)
 145           ;; otherwise, just return the current value
 146           (second style-item))
 147       (message "Warning, attempt to set invalid signencrypt style"))))
 148
 149 ;;; Security functions
 150
 151 (defun mml-smime-sign-buffer (cont)
 152   (or (mml-smime-sign cont)
 153       (error "Signing failed... inspect message logs for errors")))
 154
 155 (defun mml-smime-encrypt-buffer (cont &optional sign)
 156   (when sign
 157     (message "Combined sign and encrypt S/MIME not support yet")
 158     (sit-for 1))
 159   (or (mml-smime-encrypt cont)
 160       (error "Encryption failed... inspect message logs for errors")))
 161
 162 (defun mml-pgp-sign-buffer (cont)
 163   (or (mml1991-sign cont)
 164       (error "Signing failed... inspect message logs for errors")))
 165
 166 (defun mml-pgp-encrypt-buffer (cont &optional sign)
 167   (or (mml1991-encrypt cont sign)
 168       (error "Encryption failed... inspect message logs for errors")))
 169
 170 (defun mml-pgpmime-sign-buffer (cont)
 171   (or (mml2015-sign cont)
 172       (error "Signing failed... inspect message logs for errors")))
 173
 174 (defun mml-pgpmime-encrypt-buffer (cont &optional sign)
 175   (or (mml2015-encrypt cont sign)
 176       (error "Encryption failed... inspect message logs for errors")))
 177
 178 (defun mml-pgpauto-sign-buffer (cont)
 179   (message-goto-body)
 180   (or (if (re-search-backward "Content-Type: *multipart/.*" nil t) ; there must be a better way...
 181           (mml2015-sign cont)
 182         (mml1991-sign cont))
 183       (error "Encryption failed... inspect message logs for errors")))
 184
 185 (defun mml-pgpauto-encrypt-buffer (cont &optional sign)
 186   (message-goto-body)
 187   (or (if (re-search-backward "Content-Type: *multipart/.*" nil t) ; there must be a better way...
 188           (mml2015-encrypt cont sign)
 189         (mml1991-encrypt cont sign))
 190       (error "Encryption failed... inspect message logs for errors")))
 191
 192 (defun mml-secure-part (method &optional sign)
 193   (save-excursion
 194     (let ((tags (funcall (nth 2 (assoc method (if sign mml-sign-alist
 195                                                 mml-encrypt-alist))))))
 196       (cond ((re-search-backward
 197               "<#\\(multipart\\|part\\|external\\|mml\\)" nil t)
 198              (goto-char (match-end 0))
 199              (insert (if sign " sign=" " encrypt=") method)
 200              (while tags
 201                (let ((key (pop tags))
 202                      (value (pop tags)))
 203                  (when value
 204                    ;; Quote VALUE if it contains suspicious characters.
 205                    (when (string-match "[\"'\\~/*;() \t\n]" value)
 206                      (setq value (prin1-to-string value)))
 207                    (insert (format " %s=%s" key value))))))
 208             ((or (re-search-backward
 209                   (concat "^" (regexp-quote mail-header-separator) "\n") nil t)
 210                  (re-search-forward
 211                   (concat "^" (regexp-quote mail-header-separator) "\n") nil t))
 212              (goto-char (match-end 0))
 213              (apply 'mml-insert-tag 'part (cons (if sign 'sign 'encrypt)
 214                                                 (cons method tags))))
 215             (t (error "The message is corrupted. No mail header separator"))))))
 216
 217 (defvar mml-secure-method
 218   (if (equal mml-default-encrypt-method mml-default-sign-method)
 219       mml-default-sign-method
 220     "pgpmime")
 221   "Current security method.  Internal variable.")
 222
 223 (defun mml-secure-sign (&optional method)
 224   "Add MML tags to sign this MML part.
 225 Use METHOD if given.  Else use `mml-secure-method' or
 226 `mml-default-sign-method'."
 227   (interactive)
 228   (mml-secure-part
 229    (or method mml-secure-method mml-default-sign-method)
 230    'sign))
 231
 232 (defun mml-secure-encrypt (&optional method)
 233   "Add MML tags to encrypt this MML part.
 234 Use METHOD if given.  Else use `mml-secure-method' or
 235 `mml-default-sign-method'."
 236   (interactive)
 237   (mml-secure-part
 238    (or method mml-secure-method mml-default-sign-method)))
 239
 240 (defun mml-secure-sign-pgp ()
 241   "Add MML tags to PGP sign this MML part."
 242   (interactive)
 243   (mml-secure-part "pgp" 'sign))
 244
 245 (defun mml-secure-sign-pgpauto ()
 246   "Add MML tags to PGP-auto sign this MML part."
 247   (interactive)
 248   (mml-secure-part "pgpauto" 'sign))
 249
 250 (defun mml-secure-sign-pgpmime ()
 251   "Add MML tags to PGP/MIME sign this MML part."
 252   (interactive)
 253   (mml-secure-part "pgpmime" 'sign))
 254
 255 (defun mml-secure-sign-smime ()
 256   "Add MML tags to S/MIME sign this MML part."
 257   (interactive)
 258   (mml-secure-part "smime" 'sign))
 259
 260 (defun mml-secure-encrypt-pgp ()
 261   "Add MML tags to PGP encrypt this MML part."
 262   (interactive)
 263   (mml-secure-part "pgp"))
 264
 265 (defun mml-secure-encrypt-pgpmime ()
 266   "Add MML tags to PGP/MIME encrypt this MML part."
 267   (interactive)
 268   (mml-secure-part "pgpmime"))
 269
 270 (defun mml-secure-encrypt-smime ()
 271   "Add MML tags to S/MIME encrypt this MML part."
 272   (interactive)
 273   (mml-secure-part "smime"))
 274
 275 ;; defuns that add the proper <#secure ...> tag to the top of the message body
 276 (defun mml-secure-message (method &optional modesym)
 277   (let ((mode (prin1-to-string modesym))
 278         (tags (append
 279                (if (or (eq modesym 'sign)
 280                        (eq modesym 'signencrypt))
 281                    (funcall (nth 2 (assoc method mml-sign-alist))))
 282                (if (or (eq modesym 'encrypt)
 283                        (eq modesym 'signencrypt))
 284                    (funcall (nth 2 (assoc method mml-encrypt-alist))))))
 285         insert-loc)
 286     (mml-unsecure-message)
 287     (save-excursion
 288       (goto-char (point-min))
 289       (cond ((re-search-forward
 290               (concat "^" (regexp-quote mail-header-separator) "\n") nil t)
 291              (goto-char (setq insert-loc (match-end 0)))
 292              (unless (looking-at "<#secure")
 293                (apply 'mml-insert-tag
 294                 'secure 'method method 'mode mode tags)))
 295             (t (error
 296                 "The message is corrupted. No mail header separator"))))
 297     (when (eql insert-loc (point))
 298       (forward-line 1))))
 299
 300 (defun mml-unsecure-message ()
 301   "Remove security related MML tags from message."
 302   (interactive)
 303   (save-excursion
 304     (goto-char (point-max))
 305     (when (re-search-backward "^<#secure.*>\n" nil t)
 306       (delete-region (match-beginning 0) (match-end 0)))))
 307
 308
 309 (defun mml-secure-message-sign (&optional method)
 310   "Add MML tags to sign the entire message.
 311 Use METHOD if given. Else use `mml-secure-method' or
 312 `mml-default-sign-method'."
 313   (interactive)
 314   (mml-secure-message
 315    (or method mml-secure-method mml-default-sign-method)
 316    'sign))
 317
 318 (defun mml-secure-message-sign-encrypt (&optional method)
 319   "Add MML tag to sign and encrypt the entire message.
 320 Use METHOD if given. Else use `mml-secure-method' or
 321 `mml-default-sign-method'."
 322   (interactive)
 323   (mml-secure-message
 324    (or method mml-secure-method mml-default-sign-method)
 325    'signencrypt))
 326
 327 (defun mml-secure-message-encrypt (&optional method)
 328   "Add MML tag to encrypt the entire message.
 329 Use METHOD if given. Else use `mml-secure-method' or
 330 `mml-default-sign-method'."
 331   (interactive)
 332   (mml-secure-message
 333    (or method mml-secure-method mml-default-sign-method)
 334    'encrypt))
 335
 336 (defun mml-secure-message-sign-smime ()
 337   "Add MML tag to encrypt/sign the entire message."
 338   (interactive)
 339   (mml-secure-message "smime" 'sign))
 340
 341 (defun mml-secure-message-sign-pgp ()
 342   "Add MML tag to encrypt/sign the entire message."
 343   (interactive)
 344   (mml-secure-message "pgp" 'sign))
 345
 346 (defun mml-secure-message-sign-pgpmime ()
 347   "Add MML tag to encrypt/sign the entire message."
 348   (interactive)
 349   (mml-secure-message "pgpmime" 'sign))
 350
 351 (defun mml-secure-message-sign-pgpauto ()
 352   "Add MML tag to encrypt/sign the entire message."
 353   (interactive)
 354   (mml-secure-message "pgpauto" 'sign))
 355
 356 (defun mml-secure-message-encrypt-smime (&optional dontsign)
 357   "Add MML tag to encrypt and sign the entire message.
 358 If called with a prefix argument, only encrypt (do NOT sign)."
 359   (interactive "P")
 360   (mml-secure-message "smime" (if dontsign 'encrypt 'signencrypt)))
 361
 362 (defun mml-secure-message-encrypt-pgp (&optional dontsign)
 363   "Add MML tag to encrypt and sign the entire message.
 364 If called with a prefix argument, only encrypt (do NOT sign)."
 365   (interactive "P")
 366   (mml-secure-message "pgp" (if dontsign 'encrypt 'signencrypt)))
 367
 368 (defun mml-secure-message-encrypt-pgpmime (&optional dontsign)
 369   "Add MML tag to encrypt and sign the entire message.
 370 If called with a prefix argument, only encrypt (do NOT sign)."
 371   (interactive "P")
 372   (mml-secure-message "pgpmime" (if dontsign 'encrypt 'signencrypt)))
 373
 374 (defun mml-secure-message-encrypt-pgpauto (&optional dontsign)
 375   "Add MML tag to encrypt and sign the entire message.
 376 If called with a prefix argument, only encrypt (do NOT sign)."
 377   (interactive "P")
 378   (mml-secure-message "pgpauto" (if dontsign 'encrypt 'signencrypt)))
 379
 380 (provide 'mml-sec)
 381
 382 ;;; mml-sec.el ends here