From 23f87bede063c31c164f97278caabdc5cf5e6980 Mon Sep 17 00:00:00 2001 From: Miles Bader Date: Sat, 4 Sep 2004 13:13:48 +0000 Subject: Revision: miles@gnu.org--gnu-2004/emacs--cvs-trunk--0--patch-523 Merge from emacs--gnus--5.10, gnus--rel--5.10 Patches applied: * miles@gnu.org--gnu-2004/emacs--gnus--5.10--base-0 tag of miles@gnu.org--gnu-2004/emacs--cvs-trunk--0--patch-464 * miles@gnu.org--gnu-2004/emacs--gnus--5.10--patch-1 Import from CVS branch gnus-5_10-branch * miles@gnu.org--gnu-2004/emacs--gnus--5.10--patch-2 Merge from lorentey@elte.hu--2004/emacs--multi-tty--0, emacs--cvs-trunk--0 * miles@gnu.org--gnu-2004/emacs--gnus--5.10--patch-3 Merge from gnus--rel--5.10 * miles@gnu.org--gnu-2004/emacs--gnus--5.10--patch-4 Merge from gnus--rel--5.10 * miles@gnu.org--gnu-2004/gnus--rel--5.10--patch-18 Update from CVS * miles@gnu.org--gnu-2004/gnus--rel--5.10--patch-19 Remove autoconf-generated files from archive * miles@gnu.org--gnu-2004/gnus--rel--5.10--patch-20 Update from CVS --- lisp/gnus/smime.el | 644 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 644 insertions(+) create mode 100644 lisp/gnus/smime.el (limited to 'lisp/gnus/smime.el') diff --git a/lisp/gnus/smime.el b/lisp/gnus/smime.el new file mode 100644 index 00000000000..a1f9e902577 --- /dev/null +++ b/lisp/gnus/smime.el @@ -0,0 +1,644 @@ +;;; smime.el --- S/MIME support library +;; Copyright (c) 2000, 2001, 2003 Free Software Foundation, Inc. + +;; Author: Simon Josefsson +;; Keywords: SMIME X.509 PEM OpenSSL + +;; This file is part of GNU Emacs. + +;; 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 2, 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 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., 59 Temple Place - Suite 330, +;; Boston, MA 02111-1307, USA. + +;;; Commentary: + +;; This library perform S/MIME operations from within Emacs. +;; +;; Functions for fetching certificates from public repositories are +;; provided, currently only from DNS. LDAP support (via EUDC) is planned. +;; +;; It uses OpenSSL (tested with version 0.9.5a and 0.9.6) for signing, +;; encryption and decryption. +;; +;; Some general knowledge of S/MIME, X.509, PKCS#12, PEM etc is +;; probably required to use this library in any useful way. +;; Especially, don't expect this library to buy security for you. If +;; you don't understand what you are doing, you're as likely to lose +;; security than gain any by using this library. +;; +;; This library is not intended to provide a "raw" API for S/MIME, +;; PKCSx or similar, it's intended to perform common operations +;; done on messages encoded in these formats. The terminology chosen +;; reflect this. +;; +;; The home of this file is in Gnus CVS, but also available from +;; http://josefsson.org/smime.html. + +;;; Quick introduction: + +;; Get your S/MIME certificate from VeriSign or someplace. I used +;; Netscape to generate the key and certificate request and stuff, and +;; Netscape can export the key into PKCS#12 format. +;; +;; Enter OpenSSL. To be able to use this library, it need to have the +;; SMIME key readable in PEM format. OpenSSL is used to convert the +;; key: +;; +;; $ openssl pkcs12 -in mykey.p12 -clcerts -nodes > mykey.pem +;; ... +;; +;; Now, use M-x customize-variable smime-keys and add mykey.pem as +;; a key. +;; +;; Now you should be able to sign messages! Create a buffer and write +;; something and run M-x smime-sign-buffer RET RET and you should see +;; your message MIME armoured and a signature. Encryption, M-x +;; smime-encrypt-buffer, should also work. +;; +;; To be able to verify messages you need to build up trust with +;; someone. Perhaps you trust the CA that issued your certificate, at +;; least I did, so I export it's certificates from my PKCS#12 +;; certificate with: +;; +;; $ openssl pkcs12 -in mykey.p12 -cacerts -nodes > cacert.pem +;; ... +;; +;; Now, use M-x customize-variable smime-CAs and add cacert.pem as a +;; CA certificate. +;; +;; You should now be able to sign messages, and even verify messages +;; sent by others that use the same CA as you. + +;; Bugs: +;; +;; Don't complain that this package doesn't do encrypted PEM files, +;; submit a patch instead. I store my keys in a safe place, so I +;; didn't need the encryption. Also, programming was made easier by +;; that decision. One might think that this even influenced were I +;; store my keys, and one would probably be right. :-) +;; +;; Update: Mathias Herberts sent the patch. However, it uses +;; environment variables to pass the password to OpenSSL, which is +;; slightly insecure. Hence a new todo: use a better -passin method. +;; +;; Cache password for e.g. 1h +;; +;; Suggestions and comments are appreciated, mail me at simon@josefsson.org. + +;; begin rant +;; +;; I would include pointers to introductory text on concepts used in +;; this library here, but the material I've read are so horrible I +;; don't want to recomend them. +;; +;; Why can't someone write a simple introduction to all this stuff? +;; Until then, much of this resemble security by obscurity. +;; +;; Also, I'm not going to mention anything about the wonders of +;; cryptopolitics. Oops, I just did. +;; +;; end rant + +;;; Revision history: + +;; 2000-06-05 initial version, committed to Gnus CVS contrib/ +;; 2000-10-28 retrieve certificates via DNS CERT RRs +;; 2001-10-14 posted to gnu.emacs.sources + +;;; Code: + +(require 'dig) +(eval-when-compile (require 'cl)) + +(defgroup smime nil + "S/MIME configuration.") + +(defcustom smime-keys nil + "*Map mail addresses to a file containing Certificate (and private key). +The file is assumed to be in PEM format. You can also associate additional +certificates to be sent with every message to each address." + :type '(repeat (list (string :tag "Mail address") + (file :tag "File name") + (repeat :tag "Additional certificate files" + (file :tag "File name")))) + :group 'smime) + +(defcustom smime-CA-directory nil + "*Directory containing certificates for CAs you trust. +Directory should contain files (in PEM format) named to the X.509 +hash of the certificate. This can be done using OpenSSL such as: + +$ ln -s ca.pem `openssl x509 -noout -hash -in ca.pem`.0 + +where `ca.pem' is the file containing a PEM encoded X.509 CA +certificate." + :type '(choice (const :tag "none" nil) + directory) + :group 'smime) + +(defcustom smime-CA-file nil + "*Files containing certificates for CAs you trust. +File should contain certificates in PEM format." + :type '(choice (const :tag "none" nil) + file) + :group 'smime) + +(defcustom smime-certificate-directory "~/Mail/certs/" + "*Directory containing other people's certificates. +It should contain files named to the X.509 hash of the certificate, +and the files themself should be in PEM format." +;The S/MIME library provide simple functionality for fetching +;certificates into this directory, so there is no need to populate it +;manually. + :type 'directory + :group 'smime) + +(defcustom smime-openssl-program + (and (condition-case () + (eq 0 (call-process "openssl" nil nil nil "version")) + (error nil)) + "openssl") + "*Name of OpenSSL binary." + :type 'string + :group 'smime) + +;; OpenSSL option to select the encryption cipher + +(defcustom smime-encrypt-cipher "-des3" + "*Cipher algorithm used for encryption." + :type '(choice (const :tag "Triple DES" "-des3") + (const :tag "DES" "-des") + (const :tag "RC2 40 bits" "-rc2-40") + (const :tag "RC2 64 bits" "-rc2-64") + (const :tag "RC2 128 bits" "-rc2-128")) + :group 'smime) + +(defcustom smime-crl-check nil + "*Check revocation status of signers certificate using CRLs. +Enabling this will have OpenSSL check the signers certificate +against a certificate revocation list (CRL). + +For this to work the CRL must be up-to-date and since they are +normally updated quite often (ie. several times a day) you +probably need some tool to keep them up-to-date. Unfortunately +Gnus cannot do this for you. + +The CRL should either be appended (in PEM format) to your +`smime-CA-file' or be located in a file (also in PEM format) in +your `smime-certificate-directory' named to the X.509 hash of the +certificate with .r0 as file name extension. + +At least OpenSSL version 0.9.7 is required for this to work." + :type '(choice (const :tag "No check" nil) + (const :tag "Check certificate" "-crl_check") + (const :tag "Check certificate chain" "-crl_check_all")) + :group 'smime) + +(defcustom smime-dns-server nil + "*DNS server to query certificates from. +If nil, use system defaults." + :type '(choice (const :tag "System defaults") + string) + :group 'smime) + +(defvar smime-details-buffer "*OpenSSL output*") + +;; Use mm-util? +(eval-and-compile + (defalias 'smime-make-temp-file + (if (fboundp 'make-temp-file) + 'make-temp-file + (lambda (prefix &optional dir-flag) ;; Simple implementation + (expand-file-name + (make-temp-name prefix) + (if (fboundp 'temp-directory) + (temp-directory) + temporary-file-directory)))))) + +;; Password dialog function + +(defun smime-ask-passphrase () + "Asks the passphrase to unlock the secret key." + (let ((passphrase + (read-passwd + "Passphrase for secret key (RET for no passphrase): "))) + (if (string= passphrase "") + nil + passphrase))) + +;; OpenSSL wrappers. + +(defun smime-call-openssl-region (b e buf &rest args) + (case (apply 'call-process-region b e smime-openssl-program nil buf nil args) + (0 t) + (1 (message "OpenSSL: An error occurred parsing the command options.") nil) + (2 (message "OpenSSL: One of the input files could not be read.") nil) + (3 (message "OpenSSL: An error occurred creating the PKCS#7 file or when reading the MIME message.") nil) + (4 (message "OpenSSL: An error occurred decrypting or verifying the message.") nil) + (t (error "Unknown OpenSSL exitcode") nil))) + +(defun smime-make-certfiles (certfiles) + (if certfiles + (append (list "-certfile" (expand-file-name (car certfiles))) + (smime-make-certfiles (cdr certfiles))))) + +;; Sign+encrypt region + +(defun smime-sign-region (b e keyfile) + "Sign region with certified key in KEYFILE. +If signing fails, the buffer is not modified. Region is assumed to +have proper MIME tags. KEYFILE is expected to contain a PEM encoded +private key and certificate as its car, and a list of additional +certificates to include in its caar. If no additional certificates is +included, KEYFILE may be the file containing the PEM encoded private +key and certificate itself." + (smime-new-details-buffer) + (let ((keyfile (or (car-safe keyfile) keyfile)) + (certfiles (and (cdr-safe keyfile) (cadr keyfile))) + (buffer (generate-new-buffer (generate-new-buffer-name " *smime*"))) + (passphrase (smime-ask-passphrase)) + (tmpfile (smime-make-temp-file "smime"))) + (if passphrase + (setenv "GNUS_SMIME_PASSPHRASE" passphrase)) + (prog1 + (when (prog1 + (apply 'smime-call-openssl-region b e (list buffer tmpfile) + "smime" "-sign" "-signer" (expand-file-name keyfile) + (append + (smime-make-certfiles certfiles) + (if passphrase + (list "-passin" "env:GNUS_SMIME_PASSPHRASE")))) + (if passphrase + (setenv "GNUS_SMIME_PASSPHRASE" "" t)) + (with-current-buffer smime-details-buffer + (insert-file-contents tmpfile) + (delete-file tmpfile))) + (delete-region b e) + (insert-buffer-substring buffer) + (goto-char b) + (when (looking-at "^MIME-Version: 1.0$") + (delete-region (point) (progn (forward-line 1) (point)))) + t) + (with-current-buffer smime-details-buffer + (goto-char (point-max)) + (insert-buffer-substring buffer)) + (kill-buffer buffer)))) + +(defun smime-encrypt-region (b e certfiles) + "Encrypt region for recipients specified in CERTFILES. +If encryption fails, the buffer is not modified. Region is assumed to +have proper MIME tags. CERTFILES is a list of filenames, each file +is expected to contain of a PEM encoded certificate." + (smime-new-details-buffer) + (let ((buffer (generate-new-buffer (generate-new-buffer-name " *smime*"))) + (tmpfile (smime-make-temp-file "smime"))) + (prog1 + (when (prog1 + (apply 'smime-call-openssl-region b e (list buffer tmpfile) + "smime" "-encrypt" smime-encrypt-cipher + (mapcar 'expand-file-name certfiles)) + (with-current-buffer smime-details-buffer + (insert-file-contents tmpfile) + (delete-file tmpfile))) + (delete-region b e) + (insert-buffer-substring buffer) + (goto-char b) + (when (looking-at "^MIME-Version: 1.0$") + (delete-region (point) (progn (forward-line 1) (point)))) + t) + (with-current-buffer smime-details-buffer + (goto-char (point-max)) + (insert-buffer-substring buffer)) + (kill-buffer buffer)))) + +;; Sign+encrypt buffer + +(defun smime-sign-buffer (&optional keyfile buffer) + "S/MIME sign BUFFER with key in KEYFILE. +KEYFILE should contain a PEM encoded key and certificate." + (interactive) + (with-current-buffer (or buffer (current-buffer)) + (smime-sign-region + (point-min) (point-max) + (if keyfile + keyfile + (smime-get-key-with-certs-by-email + (completing-read + (concat "Sign using which key? " + (if smime-keys (concat "(default " (caar smime-keys) ") ") + "")) + smime-keys nil nil (car-safe (car-safe smime-keys)))))))) + +(defun smime-encrypt-buffer (&optional certfiles buffer) + "S/MIME encrypt BUFFER for recipients specified in CERTFILES. +CERTFILES is a list of filenames, each file is expected to consist of +a PEM encoded key and certificate. Uses current buffer if BUFFER is +nil." + (interactive) + (with-current-buffer (or buffer (current-buffer)) + (smime-encrypt-region + (point-min) (point-max) + (or certfiles + (list (read-file-name "Recipient's S/MIME certificate: " + smime-certificate-directory nil)))))) + +;; Verify+decrypt region + +(defun smime-verify-region (b e) + "Verify S/MIME message in region between B and E. +Returns non-nil on success. +Any details (stdout and stderr) are left in the buffer specified by +`smime-details-buffer'." + (smime-new-details-buffer) + (let ((CAs (append (if smime-CA-file + (list "-CAfile" + (expand-file-name smime-CA-file))) + (if smime-CA-directory + (list "-CApath" + (expand-file-name smime-CA-directory)))))) + (unless CAs + (error "No CA configured")) + (if smime-crl-check + (add-to-list 'CAs smime-crl-check)) + (if (apply 'smime-call-openssl-region b e (list smime-details-buffer t) + "smime" "-verify" "-out" "/dev/null" CAs) + t + (insert-buffer-substring smime-details-buffer) + nil))) + +(defun smime-noverify-region (b e) + "Verify integrity of S/MIME message in region between B and E. +Returns non-nil on success. +Any details (stdout and stderr) are left in the buffer specified by +`smime-details-buffer'." + (smime-new-details-buffer) + (if (apply 'smime-call-openssl-region b e (list smime-details-buffer t) + "smime" "-verify" "-noverify" "-out" '("/dev/null")) + t + (insert-buffer-substring smime-details-buffer) + nil)) + +(eval-when-compile + (defvar from)) + +(defun smime-decrypt-region (b e keyfile) + "Decrypt S/MIME message in region between B and E with key in KEYFILE. +On success, replaces region with decrypted data and return non-nil. +Any details (stderr on success, stdout and stderr on error) are left +in the buffer specified by `smime-details-buffer'." + (smime-new-details-buffer) + (let ((buffer (generate-new-buffer (generate-new-buffer-name " *smime*"))) + CAs (passphrase (smime-ask-passphrase)) + (tmpfile (smime-make-temp-file "smime"))) + (if passphrase + (setenv "GNUS_SMIME_PASSPHRASE" passphrase)) + (if (prog1 + (apply 'smime-call-openssl-region b e + (list buffer tmpfile) + "smime" "-decrypt" "-recip" (expand-file-name keyfile) + (if passphrase + (list "-passin" "env:GNUS_SMIME_PASSPHRASE"))) + (if passphrase + (setenv "GNUS_SMIME_PASSPHRASE" "" t)) + (with-current-buffer smime-details-buffer + (insert-file-contents tmpfile) + (delete-file tmpfile))) + (progn + (delete-region b e) + (when (boundp 'from) + ;; `from' is dynamically bound in mm-dissect. + (insert "From: " from "\n")) + (insert-buffer-substring buffer) + (kill-buffer buffer) + t) + (with-current-buffer smime-details-buffer + (insert-buffer-substring buffer)) + (kill-buffer buffer) + (delete-region b e) + (insert-buffer-substring smime-details-buffer) + nil))) + +;; Verify+Decrypt buffer + +(defun smime-verify-buffer (&optional buffer) + "Verify integrity of S/MIME message in BUFFER. +Uses current buffer if BUFFER is nil. Returns non-nil on success. +Any details (stdout and stderr) are left in the buffer specified by +`smime-details-buffer'." + (interactive) + (with-current-buffer (or buffer (current-buffer)) + (smime-verify-region (point-min) (point-max)))) + +(defun smime-noverify-buffer (&optional buffer) + "Verify integrity of S/MIME message in BUFFER. +Does NOT verify validity of certificate (only message integrity). +Uses current buffer if BUFFER is nil. Returns non-nil on success. +Any details (stdout and stderr) are left in the buffer specified by +`smime-details-buffer'." + (interactive) + (with-current-buffer (or buffer (current-buffer)) + (smime-noverify-region (point-min) (point-max)))) + +(defun smime-decrypt-buffer (&optional buffer keyfile) + "Decrypt S/MIME message in BUFFER using KEYFILE. +Uses current buffer if BUFFER is nil, and query user of KEYFILE if it's nil. +On success, replaces data in buffer and return non-nil. +Any details (stderr on success, stdout and stderr on error) are left +in the buffer specified by `smime-details-buffer'." + (interactive) + (with-current-buffer (or buffer (current-buffer)) + (smime-decrypt-region + (point-min) (point-max) + (expand-file-name + (or keyfile + (smime-get-key-by-email + (completing-read + (concat "Decipher using which key? " + (if smime-keys (concat "(default " (caar smime-keys) ") ") + "")) + smime-keys nil nil (car-safe (car-safe smime-keys))))))))) + +;; Various operations + +(defun smime-new-details-buffer () + (with-current-buffer (get-buffer-create smime-details-buffer) + (erase-buffer))) + +(defun smime-pkcs7-region (b e) + "Convert S/MIME message between points B and E into a PKCS7 message." + (smime-new-details-buffer) + (when (smime-call-openssl-region b e smime-details-buffer "smime" "-pk7out") + (delete-region b e) + (insert-buffer-substring smime-details-buffer) + t)) + +(defun smime-pkcs7-certificates-region (b e) + "Extract any certificates enclosed in PKCS7 message between points B and E." + (smime-new-details-buffer) + (when (smime-call-openssl-region + b e smime-details-buffer "pkcs7" "-print_certs" "-text") + (delete-region b e) + (insert-buffer-substring smime-details-buffer) + t)) + +(defun smime-pkcs7-email-region (b e) + "Get email addresses contained in certificate between points B and E. +A string or a list of strings is returned." + (smime-new-details-buffer) + (when (smime-call-openssl-region + b e smime-details-buffer "x509" "-email" "-noout") + (delete-region b e) + (insert-buffer-substring smime-details-buffer) + t)) + +;; Utility functions + +(defun smime-get-certfiles (keyfile keys) + (if keys + (let ((curkey (car keys)) + (otherkeys (cdr keys))) + (if (string= keyfile (cadr curkey)) + (caddr curkey) + (smime-get-certfiles keyfile otherkeys))))) + +;; Use mm-util? +(eval-and-compile + (defalias 'smime-point-at-eol + (if (fboundp 'point-at-eol) + 'point-at-eol + 'line-end-position))) + +(defun smime-buffer-as-string-region (b e) + "Return each line in region between B and E as a list of strings." + (save-excursion + (goto-char b) + (let (res) + (while (< (point) e) + (let ((str (buffer-substring (point) (smime-point-at-eol)))) + (unless (string= "" str) + (push str res))) + (forward-line)) + res))) + +;; Find certificates + +(defun smime-mail-to-domain (mailaddr) + (if (string-match "@" mailaddr) + (replace-match "." 'fixedcase 'literal mailaddr) + mailaddr)) + +(defun smime-cert-by-dns (mail) + (let* ((dig-dns-server smime-dns-server) + (digbuf (dig-invoke (smime-mail-to-domain mail) "cert" nil nil "+vc")) + (retbuf (generate-new-buffer (format "*certificate for %s*" mail))) + (certrr (with-current-buffer digbuf + (dig-extract-rr (smime-mail-to-domain mail) "cert"))) + (cert (and certrr (dig-rr-get-pkix-cert certrr)))) + (if cert + (with-current-buffer retbuf + (insert "-----BEGIN CERTIFICATE-----\n") + (let ((i 0) (len (length cert))) + (while (> (- len 64) i) + (insert (substring cert i (+ i 64)) "\n") + (setq i (+ i 64))) + (insert (substring cert i len) "\n")) + (insert "-----END CERTIFICATE-----\n")) + (kill-buffer retbuf) + (setq retbuf nil)) + (kill-buffer digbuf) + retbuf)) + +;; User interface. + +(defvar smime-buffer "*SMIME*") + +(defvar smime-mode-map nil) +(put 'smime-mode 'mode-class 'special) + +(unless smime-mode-map + (setq smime-mode-map (make-sparse-keymap)) + (suppress-keymap smime-mode-map) + + (define-key smime-mode-map "q" 'smime-exit) + (define-key smime-mode-map "f" 'smime-certificate-info)) + +(defun smime-mode () + "Major mode for browsing, viewing and fetching certificates. + +All normal editing commands are switched off. +\\ + +The following commands are available: + +\\{smime-mode-map}" + (interactive) + (kill-all-local-variables) + (setq major-mode 'smime-mode) + (setq mode-name "SMIME") + (setq mode-line-process nil) + (use-local-map smime-mode-map) + (buffer-disable-undo) + (setq truncate-lines t) + (setq buffer-read-only t)) + +(defun smime-certificate-info (certfile) + (interactive "fCertificate file: ") + (let ((buffer (get-buffer-create (format "*certificate %s*" certfile)))) + (switch-to-buffer buffer) + (erase-buffer) + (call-process smime-openssl-program nil buffer 'display + "x509" "-in" (expand-file-name certfile) "-text") + (fundamental-mode) + (set-buffer-modified-p nil) + (toggle-read-only t) + (goto-char (point-min)))) + +(defun smime-draw-buffer () + (with-current-buffer smime-buffer + (let (buffer-read-only) + (erase-buffer) + (insert "\nYour keys:\n") + (dolist (key smime-keys) + (insert + (format "\t\t%s: %s\n" (car key) (cadr key)))) + (insert "\nTrusted Certificate Authoritys:\n") + (insert "\nKnown Certificates:\n")))) + +(defun smime () + "Go to the SMIME buffer." + (interactive) + (unless (get-buffer smime-buffer) + (save-excursion + (set-buffer (get-buffer-create smime-buffer)) + (smime-mode))) + (smime-draw-buffer) + (switch-to-buffer smime-buffer)) + +(defun smime-exit () + "Quit the S/MIME buffer." + (interactive) + (kill-buffer (current-buffer))) + +;; Other functions + +(defun smime-get-key-by-email (email) + (cadr (assoc email smime-keys))) + +(defun smime-get-key-with-certs-by-email (email) + (cdr (assoc email smime-keys))) + +(provide 'smime) + +;;; arch-tag: e3f9b938-5085-4510-8a11-6625269c9a9e +;;; smime.el ends here -- cgit v1.2.3