;;; mml-sec.el --- A package with security functions for MML documents
-;; Copyright (C) 2000, 2001, 2002, 2003, 2004,
-;; 2005, 2006, 2007 Free Software Foundation, Inc.
+;; Copyright (C) 2000-2015 Free Software Foundation, Inc.
;; Author: Simon Josefsson <simon@josefsson.org>
;; This file is part of GNU Emacs.
-;; GNU Emacs is free software; you can redistribute it and/or modify
+;; GNU Emacs 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.
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
;; GNU Emacs 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
+;; 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, write to the
-;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
-;; Boston, MA 02110-1301, USA.
+;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
;;; Commentary:
(eval-when-compile (require 'cl))
-(if (locate-library "password-cache")
- (require 'password-cache)
- (require 'password))
-
+(autoload 'gnus-subsetp "gnus-util")
+(autoload 'mail-strip-quoted-names "mail-utils")
(autoload 'mml2015-sign "mml2015")
(autoload 'mml2015-encrypt "mml2015")
(autoload 'mml1991-sign "mml1991")
(autoload 'mml1991-encrypt "mml1991")
+(autoload 'message-fetch-field "message")
(autoload 'message-goto-body "message")
(autoload 'mml-insert-tag "mml")
(autoload 'mml-smime-sign "mml-smime")
:group 'message
:type 'boolean)
-(defcustom mml-secure-cache-passphrase password-cache
+(defcustom mml-secure-cache-passphrase
+ (if (boundp 'password-cache)
+ password-cache
+ t)
"If t, cache passphrase."
:group 'message
:type 'boolean)
-(defcustom mml-secure-passphrase-cache-expiry password-cache-expiry
+(defcustom mml-secure-passphrase-cache-expiry
+ (if (boundp 'password-cache-expiry)
+ password-cache-expiry
+ 16)
"How many seconds the passphrase is cached.
Whether the passphrase is cached at all is controlled by
`mml-secure-cache-passphrase'."
:group 'message
:type 'integer)
+(defcustom mml-secure-safe-bcc-list nil
+ "List of e-mail addresses that are safe to use in Bcc headers.
+EasyPG encrypts e-mails to Bcc addresses, and the encrypted e-mail
+by default identifies the used encryption keys, giving away the
+Bcc'ed identities. Clearly, this contradicts the original goal of
+*blind* copies.
+For an academic paper explaining the problem, see URL
+`http://crypto.stanford.edu/portia/papers/bb-bcc.pdf'.
+Use this variable to specify e-mail addresses whose owners do not
+mind if they are identifiable as recipients. This may be useful if
+you use Bcc headers to encrypt e-mails to yourself."
+ :version "25.1"
+ :group 'message
+ :type '(repeat string))
+
;;; Configuration/helper functions
(defun mml-signencrypt-style (method &optional style)
(interactive)
(mml-secure-part "smime"))
+(defun mml-secure-is-encrypted-p ()
+ "Check whether secure encrypt tag is present."
+ (save-excursion
+ (goto-char (point-min))
+ (re-search-forward
+ (concat "^" (regexp-quote mail-header-separator) "\n"
+ "<#secure[^>]+encrypt")
+ nil t)))
+
+(defun mml-secure-bcc-is-safe ()
+ "Check whether usage of Bcc is safe (or absent).
+Bcc usage is safe in two cases: first, if the current message does
+not contain an MML secure encrypt tag;
+second, if the Bcc addresses are a subset of `mml-secure-safe-bcc-list'.
+In all other cases, ask the user whether Bcc usage is safe.
+Raise error if user answers no.
+Note that this function does not produce a meaningful return value:
+either an error is raised or not."
+ (when (mml-secure-is-encrypted-p)
+ (let ((bcc (mail-strip-quoted-names (message-fetch-field "bcc"))))
+ (when bcc
+ (let ((bcc-list (mapcar #'cadr
+ (mail-extract-address-components bcc t))))
+ (unless (gnus-subsetp bcc-list mml-secure-safe-bcc-list)
+ (unless (yes-or-no-p "Message for encryption contains Bcc header.\
+ This may give away all Bcc'ed identities to all recipients.\
+ Are you sure that this is safe?\
+ (Customize `mml-secure-safe-bcc-list' to avoid this warning.) ")
+ (error "Aborted"))))))))
+
;; defuns that add the proper <#secure ...> tag to the top of the message body
(defun mml-secure-message (method &optional modesym)
(let ((mode (prin1-to-string modesym))
(defun mml-secure-message-sign (&optional method)
- "Add MML tags to sign this MML part.
+ "Add MML tags to sign the entire message.
Use METHOD if given. Else use `mml-secure-method' or
`mml-default-sign-method'."
(interactive)
- (mml-secure-part
+ (mml-secure-message
(or method mml-secure-method mml-default-sign-method)
'sign))
(provide 'mml-sec)
-;;; arch-tag: 111c56e7-df5e-4287-87d7-93ed2911ec6c
;;; mml-sec.el ends here
projects / gnus / blobdiff