lisp/pgg.el

   1 ;;; pgg.el --- glue for the various PGP implementations.
   2
   3 ;; Copyright (C) 1999, 2000, 2002, 2003, 2004,
   4 ;;   2005 Free Software Foundation, Inc.
   5
   6 ;; Author: Daiki Ueno <ueno@unixuser.org>
   7 ;; Symmetric encryption added by: Sascha Wilde <wilde@sha-bang.de>
   8 ;; Created: 1999/10/28
   9 ;; Keywords: PGP
  10
  11 ;; This file is part of GNU Emacs.
  12
  13 ;; GNU Emacs is free software; you can redistribute it and/or modify
  14 ;; it under the terms of the GNU General Public License as published by
  15 ;; the Free Software Foundation; either version 2, or (at your option)
  16 ;; any later version.
  17
  18 ;; GNU Emacs is distributed in the hope that it will be useful,
  19 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 ;; GNU General Public License for more details.
  22
  23 ;; You should have received a copy of the GNU General Public License
  24 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  25 ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  26 ;; Boston, MA 02110-1301, USA.
  27
  28 ;;; Commentary:
  29
  30 ;;; Code:
  31
  32 (require 'pgg-def)
  33 (require 'pgg-parse)
  34 (autoload 'run-at-time "timer")
  35
  36 ;; Don't merge these two `eval-when-compile's.
  37 (eval-when-compile
  38   (require 'cl))
  39
  40 ;;; @ utility functions
  41 ;;;
  42
  43 (defun pgg-invoke (func scheme &rest args)
  44   (progn
  45     (require (intern (format "pgg-%s" scheme)))
  46     (apply 'funcall (intern (format "pgg-%s-%s" scheme func)) args)))
  47
  48 (put 'pgg-save-coding-system 'lisp-indent-function 2)
  49
  50 (defmacro pgg-save-coding-system (start end &rest body)
  51   `(if (interactive-p)
  52        (let ((buffer (current-buffer)))
  53          (with-temp-buffer
  54            (let (buffer-undo-list)
  55              (insert-buffer-substring buffer ,start ,end)
  56              (encode-coding-region (point-min)(point-max)
  57                                    buffer-file-coding-system)
  58              (prog1 (save-excursion ,@body)
  59                (push nil buffer-undo-list)
  60                (ignore-errors (undo))))))
  61      (save-restriction
  62        (narrow-to-region ,start ,end)
  63        ,@body)))
  64
  65 (defun pgg-temp-buffer-show-function (buffer)
  66   (let ((window (or (get-buffer-window buffer 'visible)
  67                     (split-window-vertically))))
  68     (set-window-buffer window buffer)
  69     (shrink-window-if-larger-than-buffer window)))
  70
  71 ;; XXX `pgg-display-output-buffer' is a horrible name for this function.
  72 ;;     It should be something like `pgg-situate-output-or-display-error'.
  73 (defun pgg-display-output-buffer (start end status)
  74   "Situate en/decryption results or pop up an error buffer.
  75
  76 Text from START to END is replaced by contents of output buffer if STATUS
  77 is true, or else the output buffer is displayed."
  78   (if status
  79       (pgg-situate-output start end)
  80     (pgg-display-error-buffer)))
  81
  82 (defun pgg-situate-output (start end)
  83   "Place en/decryption result in place of current text from START to END."
  84   (delete-region start end)
  85   (insert-buffer-substring pgg-output-buffer)
  86   (decode-coding-region start (point) buffer-file-coding-system))
  87
  88 (defun pgg-display-error-buffer ()
  89   "Pop up an error buffer indicating the reason for an en/decryption failure."
  90   (let ((temp-buffer-show-function
  91          (function pgg-temp-buffer-show-function)))
  92     (with-output-to-temp-buffer pgg-echo-buffer
  93       (set-buffer standard-output)
  94       (insert-buffer-substring pgg-errors-buffer))))
  95
  96 (defvar pgg-passphrase-cache (make-vector 7 0))
  97
  98 (defvar pgg-pending-timers (make-vector 7 0)
  99   "Hash table for managing scheduled pgg cache management timers.
 100
 101 We associate key and timer, so the timer can be cancelled if a new
 102 timeout for the key is set while an old one is still pending.")
 103
 104 (defun pgg-read-passphrase (prompt &optional key notruncate)
 105   "Using PROMPT, obtain passphrase for KEY from cache or user.
 106
 107 Truncate the key to 8 trailing characters unless NOTRUNCATE is true
 108 \(default false).
 109
 110 Custom variables `pgg-cache-passphrase' and `pgg-passphrase-cache-expiry'
 111 regulate cache behavior."
 112   (or (pgg-read-passphrase-from-cache key notruncate)
 113       (read-passwd prompt)))
 114
 115 (defun pgg-read-passphrase-from-cache (key &optional notruncate)
 116   "Obtain passphrase for KEY from time-limited passphrase cache.
 117
 118 Truncate the key to 8 trailing characters unless NOTRUNCATE is true
 119 \(default false).
 120
 121 Custom variables `pgg-cache-passphrase' and `pgg-passphrase-cache-expiry'
 122 regulate cache behavior."
 123   (and pgg-cache-passphrase
 124        key (or notruncate
 125                 (setq key (pgg-truncate-key-identifier key)))
 126        (symbol-value (intern-soft key pgg-passphrase-cache))))
 127
 128 (defun pgg-add-passphrase-to-cache (key passphrase &optional notruncate)
 129   "Associate KEY with PASSPHRASE in time-limited passphrase cache.
 130
 131 Truncate the key to 8 trailing characters unless NOTRUNCATE is true
 132 \(default false).
 133
 134 Custom variables `pgg-cache-passphrase' and `pgg-passphrase-cache-expiry'
 135 regulate cache behavior."
 136
 137   (let* ((key (if notruncate key (pgg-truncate-key-identifier key)))
 138          (interned-timer-key (intern-soft key pgg-pending-timers))
 139          (old-timer (symbol-value interned-timer-key))
 140          new-timer)
 141     (when old-timer
 142         (cancel-timer old-timer)
 143         (unintern interned-timer-key pgg-pending-timers))
 144     (set (intern key pgg-passphrase-cache)
 145          passphrase)
 146     (set (intern key pgg-pending-timers)
 147          (pgg-run-at-time pgg-passphrase-cache-expiry nil
 148                            #'pgg-remove-passphrase-from-cache
 149                            key notruncate))))
 150
 151 (defun pgg-remove-passphrase-from-cache (key &optional notruncate)
 152   "Omit passphrase associated with KEY in time-limited passphrase cache.
 153
 154 Truncate the key to 8 trailing characters unless NOTRUNCATE is true
 155 \(default false).
 156
 157 This is a no-op if there is not entry for KEY (eg, it's already expired.
 158
 159 The memory for the passphrase is filled with underscores to clear any
 160 references to it.
 161
 162 Custom variables `pgg-cache-passphrase' and `pgg-passphrase-cache-expiry'
 163 regulate cache behavior."
 164   (let* ((passphrase (pgg-read-passphrase-from-cache key notruncate))
 165          (key (if notruncate key (pgg-truncate-key-identifier key)))
 166          (interned-timer-key (intern-soft key pgg-pending-timers))
 167          (old-timer (symbol-value interned-timer-key)))
 168     (when passphrase
 169       (fillarray passphrase ?_)
 170       (unintern key pgg-passphrase-cache))
 171     (when old-timer
 172       (pgg-cancel-timer old-timer)
 173       (unintern interned-timer-key pgg-pending-timers))))
 174
 175 (eval-when-compile
 176   (defmacro pgg-run-at-time-1 (time repeat function args)
 177     (when (featurep 'xemacs)
 178       (if (condition-case nil
 179               (let ((delete-itimer 'delete-itimer)
 180                     (itimer-driver-start 'itimer-driver-start)
 181                     (itimer-value 'itimer-value)
 182                     (start-itimer 'start-itimer))
 183                 (unless (or (symbol-value 'itimer-process)
 184                             (symbol-value 'itimer-timer))
 185                   (funcall itimer-driver-start))
 186                 ;; Check whether there is a bug to which the difference of
 187                 ;; the present time and the time when the itimer driver was
 188                 ;; woken up is subtracted from the initial itimer value.
 189                 (let* ((inhibit-quit t)
 190                        (ctime (current-time))
 191                        (itimer-timer-last-wakeup
 192                         (prog1
 193                             ctime
 194                           (setcar ctime (1- (car ctime)))))
 195                        (itimer-list nil)
 196                        (itimer (funcall start-itimer "pgg-run-at-time"
 197                                         'ignore 5)))
 198                   (sleep-for 0.1) ;; Accept the timeout interrupt.
 199                   (prog1
 200                       (> (funcall itimer-value itimer) 0)
 201                     (funcall delete-itimer itimer))))
 202             (error nil))
 203           `(let ((time ,time))
 204              (apply #'start-itimer "pgg-run-at-time"
 205                     ,function (if time (max time 1e-9) 1e-9)
 206                     ,repeat nil t ,args)))
 207       `(let ((time ,time)
 208              (itimers (list nil)))
 209          (setcar
 210           itimers
 211           (apply #'start-itimer "pgg-run-at-time"
 212                  (lambda (itimers repeat function &rest args)
 213                    (let ((itimer (car itimers)))
 214                      (if repeat
 215                          (progn
 216                            (set-itimer-function
 217                             itimer
 218                             (lambda (itimer repeat function &rest args)
 219                               (set-itimer-restart itimer repeat)
 220                               (set-itimer-function itimer function)
 221                               (set-itimer-function-arguments itimer args)
 222                               (apply function args)))
 223                            (set-itimer-function-arguments
 224                             itimer
 225                             (append (list itimer repeat function) args)))
 226                        (set-itimer-function
 227                         itimer
 228                         (lambda (itimer function &rest args)
 229                           (delete-itimer itimer)
 230                           (apply function args)))
 231                        (set-itimer-function-arguments
 232                         itimer
 233                         (append (list itimer function) args)))))
 234                  1e-9 (if time (max time 1e-9) 1e-9)
 235                  nil t itimers ,repeat ,function ,args))))))
 236
 237 (eval-and-compile
 238   (if (featurep 'xemacs)
 239       (progn
 240         (defun pgg-run-at-time (time repeat function &rest args)
 241           "Emulating function run as `run-at-time'.
 242 TIME should be nil meaning now, or a number of seconds from now.
 243 Return an itimer object which can be used in either `delete-itimer'
 244 or `cancel-timer'."
 245           (pgg-run-at-time-1 time repeat function args))
 246         (defun pgg-cancel-timer (timer)
 247           "Emulate cancel-timer for xemacs."
 248           (let ((delete-itimer 'delete-itimer))
 249             (funcall delete-itimer timer)))
 250         )
 251     (defalias 'pgg-run-at-time 'run-at-time)
 252     (defalias 'pgg-cancel-timer 'cancel-timer)))
 253
 254 (defmacro pgg-convert-lbt-region (start end lbt)
 255   `(let ((pgg-conversion-end (set-marker (make-marker) ,end)))
 256      (goto-char ,start)
 257      (case ,lbt
 258        (CRLF
 259         (while (progn
 260                  (end-of-line)
 261                  (> (marker-position pgg-conversion-end) (point)))
 262           (insert "\r")
 263           (forward-line 1)))
 264        (LF
 265         (while (re-search-forward "\r$" pgg-conversion-end t)
 266           (replace-match ""))))))
 267
 268 (put 'pgg-as-lbt 'lisp-indent-function 3)
 269
 270 (defmacro pgg-as-lbt (start end lbt &rest body)
 271   `(let ((inhibit-read-only t)
 272          buffer-read-only
 273          buffer-undo-list)
 274      (pgg-convert-lbt-region ,start ,end ,lbt)
 275      (let ((,end (point)))
 276        ,@body)
 277      (push nil buffer-undo-list)
 278      (ignore-errors (undo))))
 279
 280 (put 'pgg-process-when-success 'lisp-indent-function 0)
 281
 282 (defmacro pgg-process-when-success (&rest body)
 283   `(with-current-buffer pgg-output-buffer
 284      (if (zerop (buffer-size)) nil ,@body t)))
 285
 286 (defalias 'pgg-make-temp-file
 287   (if (fboundp 'make-temp-file)
 288       'make-temp-file
 289     (lambda (prefix &optional dir-flag)
 290       (let ((file (expand-file-name
 291                    (make-temp-name prefix)
 292                    (if (fboundp 'temp-directory)
 293                        (temp-directory)
 294                      temporary-file-directory))))
 295         (if dir-flag
 296             (make-directory file))
 297         file))))
 298
 299 ;;; @ interface functions
 300 ;;;
 301
 302 ;;;###autoload
 303 (defun pgg-encrypt-region (start end rcpts &optional sign passphrase)
 304   "Encrypt the current region between START and END for RCPTS.
 305
 306 If optional argument SIGN is non-nil, do a combined sign and encrypt.
 307
 308 If optional PASSPHRASE is not specified, it will be obtained from the
 309 passphrase cache or user."
 310   (interactive
 311    (list (region-beginning)(region-end)
 312          (split-string (read-string "Recipients: ") "[ \t,]+")))
 313   (let ((status
 314          (pgg-save-coding-system start end
 315            (pgg-invoke "encrypt-region" (or pgg-scheme pgg-default-scheme)
 316                        (point-min) (point-max) rcpts sign passphrase))))
 317     (when (interactive-p)
 318       (pgg-display-output-buffer start end status))
 319     status))
 320
 321 ;;;###autoload
 322 (defun pgg-encrypt-symmetric-region (start end &optional passphrase)
 323   "Encrypt the current region between START and END symmetric with passphrase.
 324
 325 If optional PASSPHRASE is not specified, it will be obtained from the
 326 cache or user."
 327   (interactive "r")
 328   (let ((status
 329          (pgg-save-coding-system start end
 330            (pgg-invoke "encrypt-symmetric-region"
 331                        (or pgg-scheme pgg-default-scheme)
 332                        (point-min) (point-max) passphrase))))
 333     (when (interactive-p)
 334       (pgg-display-output-buffer start end status))
 335     status))
 336
 337 ;;;###autoload
 338 (defun pgg-encrypt-symmetric (&optional start end passphrase)
 339   "Encrypt the current buffer using a symmetric, rather than key-pair, cipher.
 340
 341 If optional arguments START and END are specified, only encrypt within
 342 the region.
 343
 344 If optional PASSPHRASE is not specified, it will be obtained from the
 345 passphrase cache or user."
 346   (interactive)
 347   (let* ((start (or start (point-min)))
 348          (end (or end (point-max)))
 349          (status (pgg-encrypt-symmetric-region start end passphrase)))
 350     (when (interactive-p)
 351       (pgg-display-output-buffer start end status))
 352     status))
 353
 354 ;;;###autoload
 355 (defun pgg-encrypt (rcpts &optional sign start end passphrase)
 356   "Encrypt the current buffer for RCPTS.
 357
 358 If optional argument SIGN is non-nil, do a combined sign and encrypt.
 359
 360 If optional arguments START and END are specified, only encrypt within
 361 the region.
 362
 363 If optional PASSPHRASE is not specified, it will be obtained from the
 364 passphrase cache or user."
 365   (interactive (list (split-string (read-string "Recipients: ") "[ \t,]+")))
 366   (let* ((start (or start (point-min)))
 367          (end (or end (point-max)))
 368          (status (pgg-encrypt-region start end rcpts sign passphrase)))
 369     (when (interactive-p)
 370       (pgg-display-output-buffer start end status))
 371     status))
 372
 373 ;;;###autoload
 374 (defun pgg-decrypt-region (start end &optional passphrase)
 375   "Decrypt the current region between START and END.
 376
 377 If optional PASSPHRASE is not specified, it will be obtained from the
 378 passphrase cache or user."
 379   (interactive "r")
 380   (let* ((buf (current-buffer))
 381          (status
 382           (pgg-save-coding-system start end
 383             (pgg-invoke "decrypt-region" (or pgg-scheme pgg-default-scheme)
 384                         (point-min) (point-max) passphrase))))
 385     (when (interactive-p)
 386       (pgg-display-output-buffer start end status))
 387     status))
 388
 389 ;;;###autoload
 390 (defun pgg-decrypt (&optional start end passphrase)
 391   "Decrypt the current buffer.
 392
 393 If optional arguments START and END are specified, only decrypt within
 394 the region.
 395
 396 If optional PASSPHRASE is not specified, it will be obtained from the
 397 passphrase cache or user."
 398   (interactive "")
 399   (let* ((start (or start (point-min)))
 400          (end (or end (point-max)))
 401          (status (pgg-decrypt-region start end passphrase)))
 402     (when (interactive-p)
 403       (pgg-display-output-buffer start end status))
 404     status))
 405
 406 ;;;###autoload
 407 (defun pgg-sign-region (start end &optional cleartext passphrase)
 408   "Make the signature from text between START and END.
 409
 410 If the optional 3rd argument CLEARTEXT is non-nil, it does not create
 411 a detached signature.
 412
 413 If this function is called interactively, CLEARTEXT is enabled
 414 and the the output is displayed.
 415
 416 If optional PASSPHRASE is not specified, it will be obtained from the
 417 passphrase cache or user."
 418   (interactive "r")
 419   (let ((status (pgg-save-coding-system start end
 420                   (pgg-invoke "sign-region" (or pgg-scheme pgg-default-scheme)
 421                               (point-min) (point-max)
 422                               (or (interactive-p) cleartext)
 423                               passphrase))))
 424     (when (interactive-p)
 425       (pgg-display-output-buffer start end status))
 426     status))
 427
 428 ;;;###autoload
 429 (defun pgg-sign (&optional cleartext start end passphrase)
 430   "Sign the current buffer.
 431
 432 If the optional argument CLEARTEXT is non-nil, it does not create a
 433 detached signature.
 434
 435 If optional arguments START and END are specified, only sign data
 436 within the region.
 437
 438 If this function is called interactively, CLEARTEXT is enabled
 439 and the the output is displayed.
 440
 441 If optional PASSPHRASE is not specified, it will be obtained from the
 442 passphrase cache or user."
 443   (interactive "")
 444   (let* ((start (or start (point-min)))
 445          (end (or end (point-max)))
 446          (status (pgg-sign-region start end
 447                                   (or (interactive-p) cleartext)
 448                                   passphrase)))
 449     (when (interactive-p)
 450       (pgg-display-output-buffer start end status))
 451     status))
 452
 453 ;;;###autoload
 454 (defun pgg-verify-region (start end &optional signature fetch)
 455   "Verify the current region between START and END.
 456 If the optional 3rd argument SIGNATURE is non-nil, it is treated as
 457 the detached signature of the current region.
 458
 459 If the optional 4th argument FETCH is non-nil, we attempt to fetch the
 460 signer's public key from `pgg-default-keyserver-address'."
 461   (interactive "r")
 462   (let* ((packet
 463           (if (null signature) nil
 464             (with-temp-buffer
 465               (buffer-disable-undo)
 466               (if (fboundp 'set-buffer-multibyte)
 467                   (set-buffer-multibyte nil))
 468               (insert-file-contents signature)
 469               (cdr (assq 2 (pgg-decode-armor-region
 470                             (point-min)(point-max)))))))
 471          (key (cdr (assq 'key-identifier packet)))
 472          status keyserver)
 473     (and (stringp key)
 474          pgg-query-keyserver
 475          (setq key (concat "0x" (pgg-truncate-key-identifier key)))
 476          (null (pgg-lookup-key key))
 477          (or fetch (interactive-p))
 478          (y-or-n-p (format "Key %s not found; attempt to fetch? " key))
 479          (setq keyserver
 480                (or (cdr (assq 'preferred-key-server packet))
 481                    pgg-default-keyserver-address))
 482          (pgg-fetch-key keyserver key))
 483     (setq status
 484           (pgg-save-coding-system start end
 485             (pgg-invoke "verify-region" (or pgg-scheme pgg-default-scheme)
 486                         (point-min) (point-max) signature)))
 487     (when (interactive-p)
 488       (let ((temp-buffer-show-function
 489              (function pgg-temp-buffer-show-function)))
 490         (with-output-to-temp-buffer pgg-echo-buffer
 491           (set-buffer standard-output)
 492           (insert-buffer-substring (if status pgg-output-buffer
 493                                      pgg-errors-buffer)))))
 494     status))
 495
 496 ;;;###autoload
 497 (defun pgg-verify (&optional signature fetch start end)
 498   "Verify the current buffer.
 499 If the optional argument SIGNATURE is non-nil, it is treated as
 500 the detached signature of the current region.
 501 If the optional argument FETCH is non-nil, we attempt to fetch the
 502 signer's public key from `pgg-default-keyserver-address'.
 503 If optional arguments START and END are specified, only verify data
 504 within the region."
 505   (interactive "")
 506   (let* ((start (or start (point-min)))
 507          (end (or end (point-max)))
 508          (status (pgg-verify-region start end signature fetch)))
 509     (when (interactive-p)
 510       (let ((temp-buffer-show-function
 511              (function pgg-temp-buffer-show-function)))
 512         (with-output-to-temp-buffer pgg-echo-buffer
 513           (set-buffer standard-output)
 514           (insert-buffer-substring (if status pgg-output-buffer
 515                                      pgg-errors-buffer)))))
 516     status))
 517
 518 ;;;###autoload
 519 (defun pgg-insert-key ()
 520   "Insert the ASCII armored public key."
 521   (interactive)
 522   (pgg-invoke "insert-key" (or pgg-scheme pgg-default-scheme)))
 523
 524 ;;;###autoload
 525 (defun pgg-snarf-keys-region (start end)
 526   "Import public keys in the current region between START and END."
 527   (interactive "r")
 528   (pgg-save-coding-system start end
 529     (pgg-invoke "snarf-keys-region" (or pgg-scheme pgg-default-scheme)
 530                 start end)))
 531
 532 ;;;###autoload
 533 (defun pgg-snarf-keys ()
 534   "Import public keys in the current buffer."
 535   (interactive "")
 536   (pgg-snarf-keys-region (point-min) (point-max)))
 537
 538 (defun pgg-lookup-key (string &optional type)
 539   (pgg-invoke "lookup-key" (or pgg-scheme pgg-default-scheme) string type))
 540
 541 (defvar pgg-insert-url-function  (function pgg-insert-url-with-w3))
 542
 543 (defun pgg-insert-url-with-w3 (url)
 544   (ignore-errors
 545     (require 'url)
 546     (let (buffer-file-name)
 547       (url-insert-file-contents url))))
 548
 549 (defvar pgg-insert-url-extra-arguments nil)
 550 (defvar pgg-insert-url-program nil)
 551
 552 (defun pgg-insert-url-with-program (url)
 553   (let ((args (copy-sequence pgg-insert-url-extra-arguments))
 554         process)
 555     (insert
 556      (with-temp-buffer
 557        (setq process
 558              (apply #'start-process " *PGG url*" (current-buffer)
 559                     pgg-insert-url-program (nconc args (list url))))
 560        (set-process-sentinel process #'ignore)
 561        (while (eq 'run (process-status process))
 562          (accept-process-output process 5))
 563        (delete-process process)
 564        (if (and process (eq 'run (process-status process)))
 565            (interrupt-process process))
 566        (buffer-string)))))
 567
 568 (defun pgg-fetch-key (keyserver key)
 569   "Attempt to fetch a KEY from KEYSERVER for addition to PGP or GnuPG keyring."
 570   (with-current-buffer (get-buffer-create pgg-output-buffer)
 571     (buffer-disable-undo)
 572     (erase-buffer)
 573     (let ((proto (if (string-match "^[a-zA-Z\\+\\.\\\\-]+:" keyserver)
 574                      (substring keyserver 0 (1- (match-end 0))))))
 575       (save-excursion
 576         (funcall pgg-insert-url-function
 577                  (if proto keyserver
 578                    (format "http://%s:11371/pks/lookup?op=get&search=%s"
 579                            keyserver key))))
 580       (when (re-search-forward "^-+BEGIN" nil 'last)
 581         (delete-region (point-min) (match-beginning 0))
 582         (when (re-search-forward "^-+END" nil t)
 583           (delete-region (progn (end-of-line) (point))
 584                          (point-max)))
 585         (insert "\n")
 586         (with-temp-buffer
 587           (insert-buffer-substring pgg-output-buffer)
 588           (pgg-snarf-keys-region (point-min)(point-max)))))))
 589
 590
 591 (provide 'pgg)
 592
 593 ;;; arch-tag: 9cc705dd-1e6a-4c90-8dce-c3561f9a2cf4
 594 ;;; pgg.el ends here