X-Git-Url: https://cgit.sxemacs.org/?a=blobdiff_plain;f=lisp%2Fsmime.el;h=68eb030cbe723efad144476b6830cd3d3ed75d43;hb=e405b22c6b46721607c5e6c712a4705c23dee751;hp=fb76337f3ddfe7c384f066da70fd195f2a8d2da8;hpb=12e9cccc26a08023d5aa64d34e0e1d8708cde02b;p=gnus

diff --git a/lisp/smime.el b/lisp/smime.el
index fb76337f3..68eb030cb 100644
--- a/lisp/smime.el
+++ b/lisp/smime.el
@@ -1,10 +1,10 @@
 ;;; smime.el --- S/MIME support library
-;; Copyright (c) 2000 Free Software Foundation, Inc.
+;; Copyright (c) 2000, 2001, 2003 Free Software Foundation, Inc.
 
 ;; Author: Simon Josefsson <simon@josefsson.org>
 ;; Keywords: SMIME X.509 PEM OpenSSL
 
-;; This file is not a part of GNU Emacs, but the same permissions apply.
+;; 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
@@ -26,9 +26,9 @@
 ;; This library perform S/MIME operations from within Emacs.
 ;;
 ;; Functions for fetching certificates from public repositories are
-;; NOT provided (yet).
+;; provided, currently only from DNS.  LDAP support (via EUDC) is planned.
 ;;
-;; It uses OpenSSL (tested with version 0.9.5a) for signing,
+;; 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
@@ -36,6 +36,14 @@
 ;; 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:
 
@@ -76,13 +84,19 @@
 ;;
 ;; 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 this was made a lot
-;; easier by that decision.  One might think that this even influenced
-;; were I store my keys, and one would probably be right. :-)
+;; 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.
 
-;; <rant>
+;; 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
@@ -94,84 +108,224 @@
 ;; Also, I'm not going to mention anything about the wonders of
 ;; cryptopolitics.  Oops, I just did.
 ;;
-;; </rant>
+;; end rant
 
 ;;; Revision history:
 
-;; version 0 not released
+;; 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 your mail addresses to a file with your certified key.
-The file is assumed to be in PEM format and not encrypted."
+  "*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")))
+		       (file :tag "File name")
+		       (repeat :tag "Additional certificate files"
+			       (file :tag "File name"))))
   :group 'smime)
 
-(defcustom smime-CAs nil
-  "List of directories/files containing certificates for CAs you trust.
-Files should be in PEM format.
-Directories should contain files (in PEM format) named to the X.509
-hash of the certificate."
-  :type '(repeat (radio (directory :tag "Trusted CA directory")
-			(file :tag "Trusted CA file")))
+(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."
+  :version "22.1"
+  :type '(choice (const :tag "none" nil)
+		 file)
   :group 'smime)
 
 (defcustom smime-certificate-directory "~/Mail/certs/"
-  "Directory containing other people's certificates.
+  "*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."
+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 "openssl"
-  "Name of OpenSSL binary."
+(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."
+  :version "22.1"
+  :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."
+  :version "22.1"
+  :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 (error "OpenSSL: An error occurred parsing the command options."))
-    (2 (error "OpenSSL: One of the input files could not be read."))
-    (3 (error "OpenSSL: an error occurred creating the PKCS#7 file or when reading the MIME message."))
-    (4 (error "OpenSSL: an error occurred decrypting or verifying the message."))
-    (t (error "Unknown OpenSSL exitcode %s" exitcode))))
+    (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."
-  (let* ((buffer (generate-new-buffer (generate-new-buffer-name " *smime*"))))
-    (when (smime-call-openssl-region b e buffer "smime" "-sign"
-				     "-signer" (expand-file-name keyfile))
-      (delete-region b e)
-      (insert-buffer buffer)
-      (kill-buffer buffer)
-      t)))
+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."
-  (let ((buffer (generate-new-buffer (generate-new-buffer-name " *smime*"))))
-    (when (apply 'smime-call-openssl-region b e buffer "smime" "-encrypt"
-		 (mapcar 'expand-file-name certfiles))
-      (delete-region b e)
-      (insert-buffer buffer)
-      (kill-buffer buffer)
-      t)))
+  (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.
@@ -179,11 +333,15 @@ KEYFILE should contain a PEM encoded key and certificate."
   (interactive)
   (with-current-buffer (or buffer (current-buffer))
     (smime-sign-region
-     (point-min) (point-max) 
-     (or keyfile
-	 (smime-get-key-by-email
-	  (completing-read "Sign using which signature? " smime-keys nil nil
-			   (and (listp (car-safe smime-keys)) (caar smime-keys))))))))
+     (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.
@@ -192,12 +350,211 @@ a PEM encoded key and certificate.  Uses current buffer if BUFFER is
 nil."
   (interactive)
   (with-current-buffer (or buffer (current-buffer))
-    (smime-encrypt-region 
+    (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)))))
+
+(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) (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*")
@@ -249,7 +606,7 @@ The following commands are available:
       (erase-buffer)
       (insert "\nYour keys:\n")
       (dolist (key smime-keys)
-	(insert 
+	(insert
 	 (format "\t\t%s: %s\n" (car key) (cadr key))))
       (insert "\nTrusted Certificate Authoritys:\n")
       (insert "\nKnown Certificates:\n"))))
@@ -274,6 +631,10 @@ The following commands are available:
 (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