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   1 ;;; mml-sec.el --- A package with security functions for MML documents
   2
   3 ;; Copyright (C) 2000-2016 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 'gnus-subsetp "gnus-util")
  29 (autoload 'mail-strip-quoted-names "mail-utils")
  30 (autoload 'mml2015-sign "mml2015")
  31 (autoload 'mml2015-encrypt "mml2015")
  32 (autoload 'mml1991-sign "mml1991")
  33 (autoload 'mml1991-encrypt "mml1991")
  34 (autoload 'message-fetch-field "message")
  35 (autoload 'message-goto-body "message")
  36 (autoload 'mml-insert-tag "mml")
  37 (autoload 'mml-smime-sign "mml-smime")
  38 (autoload 'mml-smime-encrypt "mml-smime")
  39 (autoload 'mml-smime-sign-query "mml-smime")
  40 (autoload 'mml-smime-encrypt-query "mml-smime")
  41 (autoload 'mml-smime-verify "mml-smime")
  42 (autoload 'mml-smime-verify-test "mml-smime")
  43
  44 (defvar mml-sign-alist
  45   '(("smime"     mml-smime-sign-buffer     mml-smime-sign-query)
  46     ("pgp"       mml-pgp-sign-buffer       list)
  47     ("pgpauto"   mml-pgpauto-sign-buffer  list)
  48     ("pgpmime"   mml-pgpmime-sign-buffer   list))
  49   "Alist of MIME signer functions.")
  50
  51 (defcustom mml-default-sign-method "pgpmime"
  52   "Default sign method.
  53 The string must have an entry in `mml-sign-alist'."
  54   :version "22.1"
  55   :type '(choice (const "smime")
  56                  (const "pgp")
  57                  (const "pgpauto")
  58                  (const "pgpmime")
  59                  string)
  60   :group 'message)
  61
  62 (defvar mml-encrypt-alist
  63   '(("smime"     mml-smime-encrypt-buffer     mml-smime-encrypt-query)
  64     ("pgp"       mml-pgp-encrypt-buffer       list)
  65     ("pgpauto"   mml-pgpauto-sign-buffer  list)
  66     ("pgpmime"   mml-pgpmime-encrypt-buffer   list))
  67   "Alist of MIME encryption functions.")
  68
  69 (defcustom mml-default-encrypt-method "pgpmime"
  70   "Default encryption method.
  71 The string must have an entry in `mml-encrypt-alist'."
  72   :version "22.1"
  73   :type '(choice (const "smime")
  74                  (const "pgp")
  75                  (const "pgpauto")
  76                  (const "pgpmime")
  77                  string)
  78   :group 'message)
  79
  80 (defcustom mml-signencrypt-style-alist
  81   '(("smime"   separate)
  82     ("pgp"     combined)
  83     ("pgpauto" combined)
  84     ("pgpmime" combined))
  85   "Alist specifying if `signencrypt' results in two separate operations or not.
  86 The first entry indicates the MML security type, valid entries include
  87 the strings \"smime\", \"pgp\", and \"pgpmime\".  The second entry is
  88 a symbol `separate' or `combined' where `separate' means that MML signs
  89 and encrypt messages in a two step process, and `combined' means that MML
  90 signs and encrypt the message in one step.
  91
  92 Note that the output generated by using a `combined' mode is NOT
  93 understood by all PGP implementations, in particular PGP version
  94 2 does not support it!  See Info node `(message)Security' for
  95 details."
  96   :version "22.1"
  97   :group 'message
  98   :type '(repeat (list (choice (const :tag "S/MIME" "smime")
  99                                (const :tag "PGP" "pgp")
 100                                (const :tag "PGP/MIME" "pgpmime")
 101                                (string :tag "User defined"))
 102                        (choice (const :tag "Separate" separate)
 103                                (const :tag "Combined" combined)))))
 104
 105 (defcustom mml-secure-verbose nil
 106   "If non-nil, ask the user about the current operation more verbosely."
 107   :group 'message
 108   :type 'boolean)
 109
 110 (defcustom mml-secure-cache-passphrase
 111   (if (boundp 'password-cache)
 112       password-cache
 113     t)
 114   "If t, cache passphrase."
 115   :group 'message
 116   :type 'boolean)
 117
 118 (defcustom mml-secure-passphrase-cache-expiry
 119   (if (boundp 'password-cache-expiry)
 120       password-cache-expiry
 121     16)
 122   "How many seconds the passphrase is cached.
 123 Whether the passphrase is cached at all is controlled by
 124 `mml-secure-cache-passphrase'."
 125   :group 'message
 126   :type 'integer)
 127
 128 ;;; Configuration/helper functions
 129
 130 (defun mml-signencrypt-style (method &optional style)
 131   "Function for setting/getting the signencrypt-style used.  Takes two
 132 arguments, the method (e.g. \"pgp\") and optionally the mode
 133 \(e.g. combined).  If the mode is omitted, the current value is returned.
 134
 135 For example, if you prefer to use combined sign & encrypt with
 136 smime, putting the following in your Gnus startup file will
 137 enable that behavior:
 138
 139 \(mml-set-signencrypt-style \"smime\" combined)
 140
 141 You can also customize or set `mml-signencrypt-style-alist' instead."
 142   (let ((style-item (assoc method mml-signencrypt-style-alist)))
 143     (if style-item
 144         (if (or (eq style 'separate)
 145                 (eq style 'combined))
 146             ;; valid style setting?
 147             (setf (second style-item) style)
 148           ;; otherwise, just return the current value
 149           (second style-item))
 150       (message "Warning, attempt to set invalid signencrypt style"))))
 151
 152 ;;; Security functions
 153
 154 (defun mml-smime-sign-buffer (cont)
 155   (or (mml-smime-sign cont)
 156       (error "Signing failed... inspect message logs for errors")))
 157
 158 (defun mml-smime-encrypt-buffer (cont &optional sign)
 159   (when sign
 160     (message "Combined sign and encrypt S/MIME not support yet")
 161     (sit-for 1))
 162   (or (mml-smime-encrypt cont)
 163       (error "Encryption failed... inspect message logs for errors")))
 164
 165 (defun mml-pgp-sign-buffer (cont)
 166   (or (mml1991-sign cont)
 167       (error "Signing failed... inspect message logs for errors")))
 168
 169 (defun mml-pgp-encrypt-buffer (cont &optional sign)
 170   (or (mml1991-encrypt cont sign)
 171       (error "Encryption failed... inspect message logs for errors")))
 172
 173 (defun mml-pgpmime-sign-buffer (cont)
 174   (or (mml2015-sign cont)
 175       (error "Signing failed... inspect message logs for errors")))
 176
 177 (defun mml-pgpmime-encrypt-buffer (cont &optional sign)
 178   (or (mml2015-encrypt cont sign)
 179       (error "Encryption failed... inspect message logs for errors")))
 180
 181 (defun mml-pgpauto-sign-buffer (cont)
 182   (message-goto-body)
 183   (or (if (re-search-backward "Content-Type: *multipart/.*" nil t) ; there must be a better way...
 184           (mml2015-sign cont)
 185         (mml1991-sign cont))
 186       (error "Encryption failed... inspect message logs for errors")))
 187
 188 (defun mml-pgpauto-encrypt-buffer (cont &optional sign)
 189   (message-goto-body)
 190   (or (if (re-search-backward "Content-Type: *multipart/.*" nil t) ; there must be a better way...
 191           (mml2015-encrypt cont sign)
 192         (mml1991-encrypt cont sign))
 193       (error "Encryption failed... inspect message logs for errors")))
 194
 195 (defun mml-secure-part (method &optional sign)
 196   (save-excursion
 197     (let ((tags (funcall (nth 2 (assoc method (if sign mml-sign-alist
 198                                                 mml-encrypt-alist))))))
 199       (cond ((re-search-backward
 200               "<#\\(multipart\\|part\\|external\\|mml\\)" nil t)
 201              (goto-char (match-end 0))
 202              (insert (if sign " sign=" " encrypt=") method)
 203              (while tags
 204                (let ((key (pop tags))
 205                      (value (pop tags)))
 206                  (when value
 207                    ;; Quote VALUE if it contains suspicious characters.
 208                    (when (string-match "[\"'\\~/*;() \t\n]" value)
 209                      (setq value (prin1-to-string value)))
 210                    (insert (format " %s=%s" key value))))))
 211             ((or (re-search-backward
 212                   (concat "^" (regexp-quote mail-header-separator) "\n") nil t)
 213                  (re-search-forward
 214                   (concat "^" (regexp-quote mail-header-separator) "\n") nil t))
 215              (goto-char (match-end 0))
 216              (apply 'mml-insert-tag 'part (cons (if sign 'sign 'encrypt)
 217                                                 (cons method tags))))
 218             (t (error "The message is corrupted. No mail header separator"))))))
 219
 220 (defvar mml-secure-method
 221   (if (equal mml-default-encrypt-method mml-default-sign-method)
 222       mml-default-sign-method
 223     "pgpmime")
 224   "Current security method.  Internal variable.")
 225
 226 (defun mml-secure-sign (&optional method)
 227   "Add MML tags to sign this MML part.
 228 Use METHOD if given.  Else use `mml-secure-method' or
 229 `mml-default-sign-method'."
 230   (interactive)
 231   (mml-secure-part
 232    (or method mml-secure-method mml-default-sign-method)
 233    'sign))
 234
 235 (defun mml-secure-encrypt (&optional method)
 236   "Add MML tags to encrypt this MML part.
 237 Use METHOD if given.  Else use `mml-secure-method' or
 238 `mml-default-sign-method'."
 239   (interactive)
 240   (mml-secure-part
 241    (or method mml-secure-method mml-default-sign-method)))
 242
 243 (defun mml-secure-sign-pgp ()
 244   "Add MML tags to PGP sign this MML part."
 245   (interactive)
 246   (mml-secure-part "pgp" 'sign))
 247
 248 (defun mml-secure-sign-pgpauto ()
 249   "Add MML tags to PGP-auto sign this MML part."
 250   (interactive)
 251   (mml-secure-part "pgpauto" 'sign))
 252
 253 (defun mml-secure-sign-pgpmime ()
 254   "Add MML tags to PGP/MIME sign this MML part."
 255   (interactive)
 256   (mml-secure-part "pgpmime" 'sign))
 257
 258 (defun mml-secure-sign-smime ()
 259   "Add MML tags to S/MIME sign this MML part."
 260   (interactive)
 261   (mml-secure-part "smime" 'sign))
 262
 263 (defun mml-secure-encrypt-pgp ()
 264   "Add MML tags to PGP encrypt this MML part."
 265   (interactive)
 266   (mml-secure-part "pgp"))
 267
 268 (defun mml-secure-encrypt-pgpmime ()
 269   "Add MML tags to PGP/MIME encrypt this MML part."
 270   (interactive)
 271   (mml-secure-part "pgpmime"))
 272
 273 (defun mml-secure-encrypt-smime ()
 274   "Add MML tags to S/MIME encrypt this MML part."
 275   (interactive)
 276   (mml-secure-part "smime"))
 277
 278 ;; defuns that add the proper <#secure ...> tag to the top of the message body
 279 (defun mml-secure-message (method &optional modesym)
 280   (let ((mode (prin1-to-string modesym))
 281         (tags (append
 282                (if (or (eq modesym 'sign)
 283                        (eq modesym 'signencrypt))
 284                    (funcall (nth 2 (assoc method mml-sign-alist))))
 285                (if (or (eq modesym 'encrypt)
 286                        (eq modesym 'signencrypt))
 287                    (funcall (nth 2 (assoc method mml-encrypt-alist))))))
 288         insert-loc)
 289     (mml-unsecure-message)
 290     (save-excursion
 291       (goto-char (point-min))
 292       (cond ((re-search-forward
 293               (concat "^" (regexp-quote mail-header-separator) "\n") nil t)
 294              (goto-char (setq insert-loc (match-end 0)))
 295              (unless (looking-at "<#secure")
 296                (apply 'mml-insert-tag
 297                 'secure 'method method 'mode mode tags)))
 298             (t (error
 299                 "The message is corrupted. No mail header separator"))))
 300     (when (eql insert-loc (point))
 301       (forward-line 1))))
 302
 303 (defun mml-unsecure-message ()
 304   "Remove security related MML tags from message."
 305   (interactive)
 306   (save-excursion
 307     (goto-char (point-max))
 308     (when (re-search-backward "^<#secure.*>\n" nil t)
 309       (delete-region (match-beginning 0) (match-end 0)))))
 310
 311
 312 (defun mml-secure-message-sign (&optional method)
 313   "Add MML tags to sign the entire message.
 314 Use METHOD if given. Else use `mml-secure-method' or
 315 `mml-default-sign-method'."
 316   (interactive)
 317   (mml-secure-message
 318    (or method mml-secure-method mml-default-sign-method)
 319    'sign))
 320
 321 (defun mml-secure-message-sign-encrypt (&optional method)
 322   "Add MML tag to sign and encrypt the entire message.
 323 Use METHOD if given. Else use `mml-secure-method' or
 324 `mml-default-sign-method'."
 325   (interactive)
 326   (mml-secure-message
 327    (or method mml-secure-method mml-default-sign-method)
 328    'signencrypt))
 329
 330 (defun mml-secure-message-encrypt (&optional method)
 331   "Add MML tag to encrypt the entire message.
 332 Use METHOD if given. Else use `mml-secure-method' or
 333 `mml-default-sign-method'."
 334   (interactive)
 335   (mml-secure-message
 336    (or method mml-secure-method mml-default-sign-method)
 337    'encrypt))
 338
 339 (defun mml-secure-message-sign-smime ()
 340   "Add MML tag to encrypt/sign the entire message."
 341   (interactive)
 342   (mml-secure-message "smime" 'sign))
 343
 344 (defun mml-secure-message-sign-pgp ()
 345   "Add MML tag to encrypt/sign the entire message."
 346   (interactive)
 347   (mml-secure-message "pgp" 'sign))
 348
 349 (defun mml-secure-message-sign-pgpmime ()
 350   "Add MML tag to encrypt/sign the entire message."
 351   (interactive)
 352   (mml-secure-message "pgpmime" 'sign))
 353
 354 (defun mml-secure-message-sign-pgpauto ()
 355   "Add MML tag to encrypt/sign the entire message."
 356   (interactive)
 357   (mml-secure-message "pgpauto" 'sign))
 358
 359 (defun mml-secure-message-encrypt-smime (&optional dontsign)
 360   "Add MML tag to encrypt and sign the entire message.
 361 If called with a prefix argument, only encrypt (do NOT sign)."
 362   (interactive "P")
 363   (mml-secure-message "smime" (if dontsign 'encrypt 'signencrypt)))
 364
 365 (defun mml-secure-message-encrypt-pgp (&optional dontsign)
 366   "Add MML tag to encrypt and sign the entire message.
 367 If called with a prefix argument, only encrypt (do NOT sign)."
 368   (interactive "P")
 369   (mml-secure-message "pgp" (if dontsign 'encrypt 'signencrypt)))
 370
 371 (defun mml-secure-message-encrypt-pgpmime (&optional dontsign)
 372   "Add MML tag to encrypt and sign the entire message.
 373 If called with a prefix argument, only encrypt (do NOT sign)."
 374   (interactive "P")
 375   (mml-secure-message "pgpmime" (if dontsign 'encrypt 'signencrypt)))
 376
 377 (defun mml-secure-message-encrypt-pgpauto (&optional dontsign)
 378   "Add MML tag to encrypt and sign the entire message.
 379 If called with a prefix argument, only encrypt (do NOT sign)."
 380   (interactive "P")
 381   (mml-secure-message "pgpauto" (if dontsign 'encrypt 'signencrypt)))
 382
 383 (provide 'mml-sec)
 384
 385 ;;; mml-sec.el ends here