;;; pgg-parse.el --- OpenPGP packet parsing ;; Copyright (C) 1999, 2003 Free Software Foundation, Inc. ;; Author: Daiki Ueno ;; Created: 1999/10/28 ;; Keywords: PGP, OpenPGP, GnuPG ;; 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 module is based on ;; [OpenPGP] RFC 2440: "OpenPGP Message Format" ;; by John W. Noerenberg, II , ;; Jon Callas , Lutz Donnerhacke , ;; Hal Finney and Rodney Thayer ;; (1998/11) ;;; Code: (eval-when-compile (require 'cl)) (require 'custom) (defgroup pgg-parse () "OpenPGP packet parsing" :group 'pgg) (defcustom pgg-parse-public-key-algorithm-alist '((1 . RSA) (2 . RSA-E) (3 . RSA-S) (16 . ELG-E) (17 . DSA) (20 . ELG)) "Alist of the assigned number to the public key algorithm." :group 'pgg-parse :type '(repeat (cons (sexp :tag "Number") (sexp :tag "Type")))) (defcustom pgg-parse-symmetric-key-algorithm-alist '((1 . IDEA) (2 . 3DES) (4 . CAST5) (5 . SAFER-SK128)) "Alist of the assigned number to the simmetric key algorithm." :group 'pgg-parse :type '(repeat (cons (sexp :tag "Number") (sexp :tag "Type")))) (defcustom pgg-parse-hash-algorithm-alist '((1 . MD5) (2 . SHA1) (3 . RIPEMD160) (5 . MD2)) "Alist of the assigned number to the cryptographic hash algorithm." :group 'pgg-parse :type '(repeat (cons (sexp :tag "Number") (sexp :tag "Type")))) (defcustom pgg-parse-compression-algorithm-alist '((0 . nil); Uncompressed (1 . ZIP) (2 . ZLIB)) "Alist of the assigned number to the compression algorithm." :group 'pgg-parse :type '(repeat (cons (sexp :tag "Number") (sexp :tag "Type")))) (defcustom pgg-parse-signature-type-alist '((0 . "Signature of a binary document") (1 . "Signature of a canonical text document") (2 . "Standalone signature") (16 . "Generic certification of a User ID and Public Key packet") (17 . "Persona certification of a User ID and Public Key packet") (18 . "Casual certification of a User ID and Public Key packet") (19 . "Positive certification of a User ID and Public Key packet") (24 . "Subkey Binding Signature") (31 . "Signature directly on a key") (32 . "Key revocation signature") (40 . "Subkey revocation signature") (48 . "Certification revocation signature") (64 . "Timestamp signature.")) "Alist of the assigned number to the signature type." :group 'pgg-parse :type '(repeat (cons (sexp :tag "Number") (sexp :tag "Type")))) (defcustom pgg-ignore-packet-checksum t; XXX "If non-nil checksum of each ascii armored packet will be ignored." :group 'pgg-parse :type 'boolean) (defvar pgg-armor-header-lines '("^-----BEGIN PGP MESSAGE\\(, PART [0-9]+\\(/[0-9]+\\)?\\)?-----\r?$" "^-----BEGIN PGP PUBLIC KEY BLOCK-----\r?$" "^-----BEGIN PGP PRIVATE KEY BLOCK-----\r?$" "^-----BEGIN PGP SIGNATURE-----\r?$") "Armor headers.") (eval-and-compile (defalias 'pgg-char-int (if (fboundp 'char-int) 'char-int 'identity))) (defmacro pgg-format-key-identifier (string) `(mapconcat (lambda (c) (format "%02X" (pgg-char-int c))) ,string "") ;; `(upcase (apply #'format "%02x%02x%02x%02x%02x%02x%02x%02x" ;; (string-to-int-list ,string))) ) (defmacro pgg-parse-time-field (bytes) `(list (logior (lsh (car ,bytes) 8) (nth 1 ,bytes)) (logior (lsh (nth 2 ,bytes) 8) (nth 3 ,bytes)) 0)) (defmacro pgg-byte-after (&optional pos) `(pgg-char-int (char-after ,(or pos `(point))))) (defmacro pgg-read-byte () `(pgg-char-int (char-after (prog1 (point) (forward-char))))) (defmacro pgg-read-bytes-string (nbytes) `(buffer-substring (point) (prog1 (+ ,nbytes (point)) (forward-char ,nbytes)))) (defmacro pgg-read-bytes (nbytes) `(mapcar #'pgg-char-int (pgg-read-bytes-string ,nbytes)) ;; `(string-to-int-list (pgg-read-bytes-string ,nbytes)) ) (defmacro pgg-read-body-string (ptag) `(if (nth 1 ,ptag) (pgg-read-bytes-string (nth 1 ,ptag)) (pgg-read-bytes-string (- (point-max) (point))))) (defmacro pgg-read-body (ptag) `(mapcar #'pgg-char-int (pgg-read-body-string ,ptag)) ;; `(string-to-int-list (pgg-read-body-string ,ptag)) ) (defalias 'pgg-skip-bytes 'forward-char) (defmacro pgg-skip-header (ptag) `(pgg-skip-bytes (nth 2 ,ptag))) (defmacro pgg-skip-body (ptag) `(pgg-skip-bytes (nth 1 ,ptag))) (defmacro pgg-set-alist (alist key value) `(setq ,alist (nconc ,alist (list (cons ,key ,value))))) (when (fboundp 'define-ccl-program) (define-ccl-program pgg-parse-crc24 '(1 ((loop (read r0) (r1 ^= r0) (r2 ^= 0) (r5 = 0) (loop (r1 <<= 1) (r1 += ((r2 >> 15) & 1)) (r2 <<= 1) (if (r1 & 256) ((r1 ^= 390) (r2 ^= 19707))) (if (r5 < 7) ((r5 += 1) (repeat)))) (repeat))))) (defun pgg-parse-crc24-string (string) (let ((h (vector nil 183 1230 nil nil nil nil nil nil))) (ccl-execute-on-string pgg-parse-crc24 h string) (format "%c%c%c" (logand (aref h 1) 255) (logand (lsh (aref h 2) -8) 255) (logand (aref h 2) 255))))) (defmacro pgg-parse-length-type (c) `(cond ((< ,c 192) (cons ,c 1)) ((< ,c 224) (cons (+ (lsh (- ,c 192) 8) (pgg-byte-after (+ 2 (point))) 192) 2)) ((= ,c 255) (cons (cons (logior (lsh (pgg-byte-after (+ 2 (point))) 8) (pgg-byte-after (+ 3 (point)))) (logior (lsh (pgg-byte-after (+ 4 (point))) 8) (pgg-byte-after (+ 5 (point))))) 5)) (t;partial body length '(0 . 0)))) (defun pgg-parse-packet-header () (let ((ptag (pgg-byte-after)) length-type content-tag packet-bytes header-bytes) (if (zerop (logand 64 ptag));Old format (progn (setq length-type (logand ptag 3) length-type (if (= 3 length-type) 0 (lsh 1 length-type)) content-tag (logand 15 (lsh ptag -2)) packet-bytes 0 header-bytes (1+ length-type)) (dotimes (i length-type) (setq packet-bytes (logior (lsh packet-bytes 8) (pgg-byte-after (+ 1 i (point))))))) (setq content-tag (logand 63 ptag) length-type (pgg-parse-length-type (pgg-byte-after (1+ (point)))) packet-bytes (car length-type) header-bytes (1+ (cdr length-type)))) (list content-tag packet-bytes header-bytes))) (defun pgg-parse-packet (ptag) (case (car ptag) (1 ;Public-Key Encrypted Session Key Packet (pgg-parse-public-key-encrypted-session-key-packet ptag)) (2 ;Signature Packet (pgg-parse-signature-packet ptag)) (3 ;Symmetric-Key Encrypted Session Key Packet (pgg-parse-symmetric-key-encrypted-session-key-packet ptag)) ;; 4 -- One-Pass Signature Packet ;; 5 -- Secret Key Packet (6 ;Public Key Packet (pgg-parse-public-key-packet ptag)) ;; 7 -- Secret Subkey Packet ;; 8 -- Compressed Data Packet (9 ;Symmetrically Encrypted Data Packet (pgg-read-body-string ptag)) (10 ;Marker Packet (pgg-read-body-string ptag)) (11 ;Literal Data Packet (pgg-read-body-string ptag)) ;; 12 -- Trust Packet (13 ;User ID Packet (pgg-read-body-string ptag)) ;; 14 -- Public Subkey Packet ;; 60 .. 63 -- Private or Experimental Values )) (defun pgg-parse-packets (&optional header-parser body-parser) (let ((header-parser (or header-parser (function pgg-parse-packet-header))) (body-parser (or body-parser (function pgg-parse-packet))) result ptag) (while (> (point-max) (1+ (point))) (setq ptag (funcall header-parser)) (pgg-skip-header ptag) (push (cons (car ptag) (save-excursion (funcall body-parser ptag))) result) (if (zerop (nth 1 ptag)) (goto-char (point-max)) (forward-char (nth 1 ptag)))) result)) (defun pgg-parse-signature-subpacket-header () (let ((length-type (pgg-parse-length-type (pgg-byte-after)))) (list (pgg-byte-after (+ (cdr length-type) (point))) (1- (car length-type)) (1+ (cdr length-type))))) (defun pgg-parse-signature-subpacket (ptag) (case (car ptag) (2 ;signature creation time (cons 'creation-time (let ((bytes (pgg-read-bytes 4))) (pgg-parse-time-field bytes)))) (3 ;signature expiration time (cons 'signature-expiry (let ((bytes (pgg-read-bytes 4))) (pgg-parse-time-field bytes)))) (4 ;exportable certification (cons 'exportability (pgg-read-byte))) (5 ;trust signature (cons 'trust-level (pgg-read-byte))) (6 ;regular expression (cons 'regular-expression (pgg-read-body-string ptag))) (7 ;revocable (cons 'revocability (pgg-read-byte))) (9 ;key expiration time (cons 'key-expiry (let ((bytes (pgg-read-bytes 4))) (pgg-parse-time-field bytes)))) ;; 10 = placeholder for backward compatibility (11 ;preferred symmetric algorithms (cons 'preferred-symmetric-key-algorithm (cdr (assq (pgg-read-byte) pgg-parse-symmetric-key-algorithm-alist)))) (12 ;revocation key ) (16 ;issuer key ID (cons 'key-identifier (pgg-format-key-identifier (pgg-read-body-string ptag)))) (20 ;notation data (pgg-skip-bytes 4) (cons 'notation (let ((name-bytes (pgg-read-bytes 2)) (value-bytes (pgg-read-bytes 2))) (cons (pgg-read-bytes-string (logior (lsh (car name-bytes) 8) (nth 1 name-bytes))) (pgg-read-bytes-string (logior (lsh (car value-bytes) 8) (nth 1 value-bytes))))))) (21 ;preferred hash algorithms (cons 'preferred-hash-algorithm (cdr (assq (pgg-read-byte) pgg-parse-hash-algorithm-alist)))) (22 ;preferred compression algorithms (cons 'preferred-compression-algorithm (cdr (assq (pgg-read-byte) pgg-parse-compression-algorithm-alist)))) (23 ;key server preferences (cons 'key-server-preferences (pgg-read-body ptag))) (24 ;preferred key server (cons 'preferred-key-server (pgg-read-body-string ptag))) ;; 25 = primary user id (26 ;policy URL (cons 'policy-url (pgg-read-body-string ptag))) ;; 27 = key flags ;; 28 = signer's user id ;; 29 = reason for revocation ;; 100 to 110 = internal or user-defined )) (defun pgg-parse-signature-packet (ptag) (let* ((signature-version (pgg-byte-after)) (result (list (cons 'version signature-version))) hashed-material field n) (cond ((= signature-version 3) (pgg-skip-bytes 2) (setq hashed-material (pgg-read-bytes 5)) (pgg-set-alist result 'signature-type (cdr (assq (pop hashed-material) pgg-parse-signature-type-alist))) (pgg-set-alist result 'creation-time (pgg-parse-time-field hashed-material)) (pgg-set-alist result 'key-identifier (pgg-format-key-identifier (pgg-read-bytes-string 8))) (pgg-set-alist result 'public-key-algorithm (pgg-read-byte)) (pgg-set-alist result 'hash-algorithm (pgg-read-byte))) ((= signature-version 4) (pgg-skip-bytes 1) (pgg-set-alist result 'signature-type (cdr (assq (pgg-read-byte) pgg-parse-signature-type-alist))) (pgg-set-alist result 'public-key-algorithm (pgg-read-byte)) (pgg-set-alist result 'hash-algorithm (pgg-read-byte)) (when (>= 10000 (setq n (pgg-read-bytes 2) n (logior (lsh (car n) 8) (nth 1 n)))) (save-restriction (narrow-to-region (point)(+ n (point))) (nconc result (mapcar (function cdr) ;remove packet types (pgg-parse-packets #'pgg-parse-signature-subpacket-header #'pgg-parse-signature-subpacket))) (goto-char (point-max)))) (when (>= 10000 (setq n (pgg-read-bytes 2) n (logior (lsh (car n) 8) (nth 1 n)))) (save-restriction (narrow-to-region (point)(+ n (point))) (nconc result (mapcar (function cdr) ;remove packet types (pgg-parse-packets #'pgg-parse-signature-subpacket-header #'pgg-parse-signature-subpacket))))))) (setcdr (setq field (assq 'public-key-algorithm result)) (cdr (assq (cdr field) pgg-parse-public-key-algorithm-alist))) (setcdr (setq field (assq 'hash-algorithm result)) (cdr (assq (cdr field) pgg-parse-hash-algorithm-alist))) result)) (defun pgg-parse-public-key-encrypted-session-key-packet (ptag) (let (result) (pgg-set-alist result 'version (pgg-read-byte)) (pgg-set-alist result 'key-identifier (pgg-format-key-identifier (pgg-read-bytes-string 8))) (pgg-set-alist result 'public-key-algorithm (cdr (assq (pgg-read-byte) pgg-parse-public-key-algorithm-alist))) result)) (defun pgg-parse-symmetric-key-encrypted-session-key-packet (ptag) (let (result) (pgg-set-alist result 'version (pgg-read-byte)) (pgg-set-alist result 'symmetric-key-algorithm (cdr (assq (pgg-read-byte) pgg-parse-symmetric-key-algorithm-alist))) result)) (defun pgg-parse-public-key-packet (ptag) (let* ((key-version (pgg-read-byte)) (result (list (cons 'version key-version))) field) (cond ((= 3 key-version) (pgg-set-alist result 'creation-time (let ((bytes (pgg-read-bytes 4))) (pgg-parse-time-field bytes))) (pgg-set-alist result 'key-expiry (pgg-read-bytes 2)) (pgg-set-alist result 'public-key-algorithm (pgg-read-byte))) ((= 4 key-version) (pgg-set-alist result 'creation-time (let ((bytes (pgg-read-bytes 4))) (pgg-parse-time-field bytes))) (pgg-set-alist result 'public-key-algorithm (pgg-read-byte)))) (setcdr (setq field (assq 'public-key-algorithm result)) (cdr (assq (cdr field) pgg-parse-public-key-algorithm-alist))) result)) (defun pgg-decode-packets () (if (re-search-forward "^=\\([A-Za-z0-9+/]\\{4\\}\\)$" nil t) (let ((p (match-beginning 0)) (checksum (match-string 1))) (delete-region p (point-max)) (if (ignore-errors (base64-decode-region (point-min) p)) (or (not (fboundp 'pgg-parse-crc24-string)) pgg-ignore-packet-checksum (string-equal (base64-encode-string (pgg-parse-crc24-string (buffer-string))) checksum) (progn (message "PGP packet checksum does not match") nil)) (message "PGP packet contain invalid base64") nil)) (message "PGP packet checksum not found") nil)) (defun pgg-decode-armor-region (start end) (save-restriction (narrow-to-region start end) (goto-char (point-min)) (re-search-forward "^-+BEGIN PGP" nil t) (delete-region (point-min) (and (search-forward "\n\n") (match-end 0))) (when (pgg-decode-packets) (goto-char (point-min)) (pgg-parse-packets)))) (defun pgg-parse-armor (string) (with-temp-buffer (buffer-disable-undo) (if (fboundp 'set-buffer-multibyte) (set-buffer-multibyte nil)) (insert string) (pgg-decode-armor-region (point-min)(point)))) (eval-and-compile (defalias 'pgg-string-as-unibyte (if (fboundp 'string-as-unibyte) 'string-as-unibyte 'identity))) (defun pgg-parse-armor-region (start end) (pgg-parse-armor (pgg-string-as-unibyte (buffer-substring start end)))) (provide 'pgg-parse) ;;; arch-tag: 16c2eb82-1313-4a7c-a70f-420709b5b43e ;;; pgg-parse.el ends here