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;;; pgg-parse.el --- OpenPGP packet parsing
;; Copyright (C) 1999, 2002, 2003, 2004, 2005,
;; 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
;; Author: Daiki Ueno <ueno@unixuser.org>
;; 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 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
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs. If not, see <http://www.gnu.org/licenses/>.
;;; Commentary:
;; This module is based on
;; [OpenPGP] RFC 2440: "OpenPGP Message Format"
;; by John W. Noerenberg, II <jwn2@qualcomm.com>,
;; Jon Callas <jon@pgp.com>, Lutz Donnerhacke <lutz@iks-jena.de>,
;; Hal Finney <hal@pgp.com> and Rodney Thayer <rodney@unitran.com>
;; (1998/11)
;;; Code:
(eval-when-compile
(unless (fboundp 'declare-function) (defmacro declare-function (&rest r)))
(require 'cl))
(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) (8 . SHA256) (9 . SHA384)
(10 . SHA512))
"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-number-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-number-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-number-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)))))
(defvar pgg-parse-crc24)
(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))
;; p-d-p only calls this if it is defined, but the compiler does not
;; recognize that.
(declare-function pgg-parse-crc24-string "pgg-parse" (string))
(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