mime-pgp.el

   1 ;;; mime-pgp.el --- mime-view internal methods for PGP.
   2
   3 ;; Copyright (C) 1995,1996,1997,1998,1999,2000 Free Software Foundation, Inc.
   4
   5 ;; Author: MORIOKA Tomohiko <tomo@m17n.org>
   6 ;;      Daiki Ueno <ueno@unixuser.org>
   7 ;; Created: 1995/12/7
   8 ;;      Renamed: 1997/2/27 from tm-pgp.el
   9 ;; Keywords: PGP, security, MIME, multimedia, mail, news
  10
  11 ;; This file is part of SEMI (Secure Emacs MIME Interface).
  12
  13 ;; This program is free software; you can redistribute it and/or
  14 ;; modify it under the terms of the GNU General Public License as
  15 ;; published by the Free Software Foundation; either version 2, or (at
  16 ;; your option) any later version.
  17
  18 ;; This program is distributed in the hope that it will be useful, but
  19 ;; WITHOUT ANY WARRANTY; without even the implied warranty of
  20 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  21 ;; 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 ;;    This module is based on
  31
  32 ;;      [security-multipart] RFC 1847: "Security Multiparts for MIME:
  33 ;;          Multipart/Signed and Multipart/Encrypted" by
  34 ;;          Jim Galvin <galvin@tis.com>, Sandy Murphy <sandy@tis.com>,
  35 ;;          Steve Crocker <crocker@cybercash.com> and
  36 ;;          Ned Freed <ned@innosoft.com> (1995/10)
  37
  38 ;;      [PGP/MIME] RFC 2015: "MIME Security with Pretty Good Privacy
  39 ;;          (PGP)" by Michael Elkins <elkins@aero.org> (1996/6)
  40
  41 ;;      [PGP-kazu] draft-kazu-pgp-mime-00.txt: "PGP MIME Integration"
  42 ;;          by Kazuhiko Yamamoto <kazu@is.aist-nara.ac.jp> (1995/10;
  43 ;;          expired)
  44
  45 ;;      [OpenPGP/MIME] draft-ietf-openpgp-mime-02.txt: "MIME
  46 ;;          Security with OpenPGP" by
  47 ;;          John W. Noerenberg II <jwn2@qualcomm.com>,
  48 ;;          Dave Del Torto <ddt@cryptorights.org> and
  49 ;;          Michael Elkins <michael_elkins@nai.com> (2000/8)
  50
  51 ;;; Code:
  52
  53 (require 'mime-play)
  54 (require 'epg)
  55
  56 ;;; @ Internal method for multipart/signed
  57 ;;;
  58 ;;; It is based on RFC 1847 (security-multipart).
  59
  60 (defun mime-verify-multipart/signed (entity situation)
  61   "Internal method to verify multipart/signed."
  62   (mime-play-entity
  63    (nth 1 (mime-entity-children entity)) ; entity-info of signature
  64    (list (assq 'mode situation)) ; play-mode
  65    ))
  66
  67
  68 ;;; @ internal method for application/pgp
  69 ;;;
  70 ;;; It is based on draft-kazu-pgp-mime-00.txt (PGP-kazu).
  71
  72 (defun mime-view-application/pgp (entity situation)
  73   (let* ((p-win (or (get-buffer-window (current-buffer))
  74                     (get-largest-window)))
  75          (new-name
  76           (format "%s-%s" (buffer-name) (mime-entity-number entity)))
  77          (mother (current-buffer))
  78          (preview-buffer (concat "*Preview-" (buffer-name) "*"))
  79          representation-type message-buf context signature plain)
  80     (set-buffer (setq message-buf (get-buffer-create new-name)))
  81     (erase-buffer)
  82     (mime-insert-entity entity)
  83     (cond ((progn
  84              (goto-char (point-min))
  85              (re-search-forward "^-+BEGIN PGP SIGNED MESSAGE-+$" nil t))
  86            (setq context (epg-make-context))
  87            (epg-verify-string
  88             context
  89             (buffer-substring (match-beginning 0)(point-max)))
  90            (setq signature
  91                  (reverse (epg-context-result-for context 'verify)))
  92            (while signature
  93              (message "%s: %s %s %s"
  94                       (epg-signature-status (car signature))
  95                       (epg-signature-key-id (car signature))
  96                       (epg-signature-user-id (car signature))
  97                       (epg-signature-validity (car signature)))
  98              (setq signature (cdr signature)))
  99            (goto-char (point-min))
 100            (delete-region
 101             (point-min)
 102             (and
 103              (re-search-forward "^-+BEGIN PGP SIGNED MESSAGE-+\n\n")
 104              (match-end 0)))
 105            (delete-region
 106             (and (re-search-forward "^-+BEGIN PGP SIGNATURE-+")
 107                  (match-beginning 0))
 108             (point-max))
 109            (goto-char (point-min))
 110            (while (re-search-forward "^- -" nil t)
 111              (replace-match "-"))
 112            (setq representation-type (if (mime-entity-cooked-p entity)
 113                                          'cooked)))
 114           ((progn
 115              (goto-char (point-min))
 116              (re-search-forward "^-+BEGIN PGP MESSAGE-+$" nil t))
 117            (setq context (epg-make-context))
 118            (setq plain
 119                  (epg-decrypt-string
 120                   context
 121                   (buffer-substring (point-min)(point-max))))
 122            (delete-region (point-min)(point-max))
 123            (insert plain)
 124            (setq representation-type 'binary)))
 125     (setq major-mode 'mime-show-message-mode)
 126     (save-window-excursion
 127       (mime-view-buffer nil preview-buffer mother
 128                         nil representation-type)
 129       (make-local-variable 'mime-view-temp-message-buffer)
 130       (setq mime-view-temp-message-buffer message-buf))
 131     (set-window-buffer p-win preview-buffer)))
 132
 133
 134 ;;; @ Internal method for application/pgp-signature
 135 ;;;
 136 ;;; It is based on RFC 2015 (PGP/MIME) and
 137 ;;; draft-ietf-openpgp-mime-02.txt (OpenPGP/MIME).
 138
 139 (defun mime-verify-application/pgp-signature (entity situation)
 140   "Internal method to check PGP/MIME signature."
 141   (let* ((entity-node-id (mime-entity-node-id entity))
 142          (mother (mime-entity-parent entity))
 143          (knum (car entity-node-id))
 144          (onum (if (> knum 0)
 145                    (1- knum)
 146                  (1+ knum)))
 147          (orig-entity (nth onum (mime-entity-children mother)))
 148          (context (epg-make-context))
 149          signature)
 150     (epg-verify-string context
 151                        (mime-entity-content entity)
 152                        (with-temp-buffer
 153                          (if (fboundp 'set-buffer-multibyte)
 154                              (set-buffer-multibyte nil))
 155                          (mime-insert-entity orig-entity)
 156                          (buffer-substring)))
 157     (setq signature
 158           (reverse (epg-context-result-for context 'verify)))
 159     (while signature
 160       (message "%s: %s %s %s"
 161                (epg-signature-status (car signature))
 162                (epg-signature-key-id (car signature))
 163                (epg-signature-user-id (car signature))
 164                (epg-signature-validity (car signature)))
 165       (setq signature (cdr signature)))))
 166
 167
 168 ;;; @ Internal method for application/pgp-encrypted
 169 ;;;
 170 ;;; It is based on RFC 2015 (PGP/MIME) and
 171 ;;; draft-ietf-openpgp-mime-02.txt (OpenPGP/MIME).
 172
 173 (defun mime-decrypt-application/pgp-encrypted (entity situation)
 174   (let* ((entity-node-id (mime-entity-node-id entity))
 175          (mother (mime-entity-parent entity))
 176          (knum (car entity-node-id))
 177          (onum (if (> knum 0)
 178                    (1- knum)
 179                  (1+ knum)))
 180          (orig-entity (nth onum (mime-entity-children mother))))
 181     (mime-view-application/pgp orig-entity situation)))
 182
 183
 184 ;;; @ Internal method for application/pgp-keys
 185 ;;;
 186 ;;; It is based on RFC 2015 (PGP/MIME) and
 187 ;;; draft-ietf-openpgp-mime-02.txt (OpenPGP/MIME).
 188
 189 (defun mime-add-application/pgp-keys (entity situation)
 190   (with-temp-buffer
 191     (mime-insert-entity-content entity)
 192     (mime-decode-region (point-min) (point-max)
 193                         (cdr (assq 'encoding situation)))
 194     (epg-import-keys-from-string (epg-make-context)
 195                                  (buffer-substring (point-min)(point-max)))
 196     (epa-list-keys)))
 197
 198
 199 ;;; @ Internal method for application/pkcs7-signature
 200 ;;;
 201 ;;; It is based on the S/MIME user interface in Gnus.
 202
 203 (defun mime-verify-application/pkcs7-signature (entity situation)
 204   "Internal method to check S/MIME signature."
 205   (with-temp-buffer
 206     (mime-insert-entity (mime-find-root-entity entity))
 207     (let ((good-signature (smime-noverify-buffer))
 208           (good-certificate
 209            (and (or smime-CA-file smime-CA-directory)
 210                 (smime-verify-buffer))))
 211       (if (not good-signature)
 212           ;; we couldn't verify message, fail with openssl output as message
 213           (save-excursion
 214             (mime-show-echo-buffer)
 215             (set-buffer mime-echo-buffer-name)
 216             (set-window-start
 217              (get-buffer-window mime-echo-buffer-name)
 218              (point-max))
 219             (insert-buffer-substring smime-details-buffer))
 220         ;; verify mail addresses in mail against those in certificate
 221         (when (and (smime-pkcs7-region (point-min)(point-max))
 222                    (smime-pkcs7-certificates-region (point-min)(point-max)))
 223           (if (not (member
 224                     (downcase
 225                      (nth 1 (std11-extract-address-components
 226                              (mime-entity-fetch-field
 227                               (mime-find-root-entity entity) "From"))))
 228                     (mime-smime-pkcs7-email-buffer (current-buffer))))
 229               (message "Sender address forged")
 230             (if good-certificate
 231                 (message "Ok (sender authenticated)")
 232               (message "Integrity OK (sender unknown)"))))))))
 233
 234 (defun mime-smime-pkcs7-email-buffer (buffer)
 235   (with-temp-buffer
 236     (insert-buffer-substring buffer)
 237     (goto-char (point-min))
 238     (let (addresses)
 239       (while (re-search-forward "-----END CERTIFICATE-----" nil t)
 240         (if (smime-pkcs7-email-region (point-min)(point))
 241             (setq addresses (append (split-string
 242                                      (buffer-substring (point-min)(point))
 243                                      "[\n\r]+")
 244                                     addresses)))
 245         (delete-region (point-min)(point)))
 246       (mapcar #'downcase addresses))))
 247
 248
 249 ;;; @ Internal method for application/pkcs7-mime
 250 ;;;
 251 ;;; It is based on RFC 2633 (S/MIME version 3).
 252
 253 (defun mime-view-application/pkcs7-mime (entity situation)
 254   (let* ((p-win (or (get-buffer-window (current-buffer))
 255                     (get-largest-window)))
 256          (new-name
 257           (format "%s-%s" (buffer-name) (mime-entity-number entity)))
 258          (mother (current-buffer))
 259          (preview-buffer (concat "*Preview-" (buffer-name) "*"))
 260          message-buf)
 261     (when (memq (or (cdr (assq 'smime-type situation)) 'enveloped-data)
 262                 '(enveloped-data signed-data))
 263       (set-buffer (setq message-buf (get-buffer-create new-name)))
 264       (let ((inhibit-read-only t)
 265             buffer-read-only)
 266         (erase-buffer)
 267         (mime-insert-entity entity)
 268         (smime-decrypt-buffer))
 269       (setq major-mode 'mime-show-message-mode)
 270       (save-window-excursion
 271         (mime-view-buffer nil preview-buffer mother
 272                           nil 'binary)
 273         (make-local-variable 'mime-view-temp-message-buffer)
 274         (setq mime-view-temp-message-buffer message-buf))
 275       (set-window-buffer p-win preview-buffer))))
 276
 277
 278 ;;; @ end
 279 ;;;
 280
 281 (provide 'mime-pgp)
 282
 283 (run-hooks 'mime-pgp-load-hook)
 284
 285 ;;; mime-pgp.el ends here