jv@mh.nl (Johan Vromans) (05/11/91)
This file defines the functions to have automatic validation and
insertion of MD4 signatures using GNUS.
See the recent postings in comp.sources.misc for a discussion of MD4.
#!/bin/sh
# This is a shell archive (produced by shar 3.49)
# To extract the files from this archive, save it to a file, remove
# everything above the "!/bin/sh" line above, and type "sh file_name".
#
# made 05/11/1991 14:27 UTC by jv@pronto
# Source directory /u1/users/jv
#
# existing files will NOT be overwritten unless -c is specified
#
# This shar contains:
# length mode name
# ------ ---------- ------------------------------------------
# 4010 -r--r--r-- md4.el
#
# ============= md4.el ==============
if test -f 'md4.el' -a X"$1" != X"-c"; then
echo 'x - skipping md4.el (File already exists)'
else
echo 'x - extracting md4.el (Text)'
sed 's/^X//' << 'SHAR_EOF' > 'md4.el' &&
X;; @(#)@ md4 1.1 - MD4 support for GNUS
X;;
X;; This file defines functions to calculate a MD4 signature, add
X;; it to outgoing postings, and validate it on incoming postings.
X;;
X;; It uses "gnus-Inews-article-hook", called by GNUS just before passing
X;; the articel to inews, to install the signature.
X;;
X;; "gnus-Article-prepare-hook" is used to validate the signature on
X;; an article if you read it.
X;;
X;; This file, if useful, is covered by the GPL.
X;;
X;; Johan Vromans <jv@mh.nl>
X
X;; Customizations
X
X(defvar md4-command "md4" "*Where to find md4")
X
X(defvar md4-signature-header "X-Md4-Signature")
X
X(defvar md4-insertion t
X "*Controls MD4 signature insertion. If nil, no signature is
X calculated nor inserted.")
X
X(defvar md4-validation 1
X "*Controls MD4 signature validation. If nil, no validation is
X performed. If t, validation is performed, and failures are reported.
X Any other value causes validation to be performed, and failures as
X well as successes to be reported.")
X
X;; Hook definitions and insertions.
X
X(add-hook 'gnus-Inews-article-hook 'md4-add-signature)
X(add-hook 'gnus-Article-prepare-hook 'md4-validate-signature)
X;;
X;; Calcuates the MD4 signature for the article to be posted, which
X;; is assumed to be in the current buffer.
X;;
X(defun md4-add-signature ()
X "Adds a MD4-signature to the article being posted. Must be called
Xfrom gnus-Inews-article-hook."
X (interactive)
X
X (if (null md4-insertion)
X nil
X (let (start-of-body end-of-body sigfile)
X
X ;; .signature handling. may be system specific
X (goto-char (point-max))
X (setq end-of-body (point-marker))
X (if (file-exists-p
X (setq sigfile
X (or gnus-signature-file (expand-file-name "~/.signature"))))
X (progn
X (insert "-- \n") ; that is what I get inserted...
X (insert-file sigfile))
X (setq sigfile nil))
X
X (goto-char (point-min))
X (search-forward "\n\n")
X (setq start-of-body (point-marker)) ; remember where
X
X ;; Run md4 and add the signature.
X (forward-line -1)
X (insert md4-signature-header ": ")
X (insert (md4-signature-region start-of-body (point-max)))
X (insert "\n")
X
X (if sigfile
X (delete-region end-of-body (point-max)))
X )))
X
X;;
X;; Validate MD4 signature. A message is shown with the result.
X;; If the signature does not match, buffer "*MD4 Buffer*" holds more
X;; information.
X;;
X(defun md4-validate-signature ()
X "Checks a MD4-signature in the article being read. May be called
Xfrom gnus-article-prepare-hook."
X (interactive)
X
X (if (null md4-validation)
X nil
X (let (start-of-body)
X (goto-char (point-min))
X (search-forward "\n\n")
X (setq start-of-body (point-marker)) ; remember where
X
X ;; Check if a signature header is present
X (goto-char (point-min))
X (if (search-forward
X (concat "\n" md4-signature-header ": ")
X start-of-body t)
X (let (signature (here (point)))
X (forward-line 1)
X (setq signature (buffer-substring here (1- (point))))
X
X ;; Validate
X (if (string=
X signature
X (md4-signature-region start-of-body (point-max)))
X (progn
X (if (not (equal md4-validation t))
X (message "MD4 signature valid."))
X (bury-buffer md4-buffer))
X (beep)
X (save-excursion
X (set-buffer md4-buffer)
X (goto-char (point-min))
X (insert (message "MD4 signature mismatch!")
X "\nPosted: " signature
X "\nCalculated: ")
X (goto-char (point-min))))
X )))))
X
X(defun md4-signature-region (start end)
X "Calculates MD4 signature."
X
X ;; Get buffer and clear it
X (setq md4-buffer (get-buffer-create "*MD4 Buffer*"))
X (save-excursion
X (set-buffer md4-buffer)
X (erase-buffer))
X
X ;; Run md4
X (call-process-region start end
X md4-command nil md4-buffer nil)
X
X ;; Verify normal result
X (save-excursion
X (set-buffer md4-buffer)
X (if (= (buffer-size) 33)
X (buffer-substring (point-min) (1- (point-max)))
X (error "Unexpected result from %s: %s" md4-command
X (buffer-substring (point-min) (point-max))))))
SHAR_EOF
chmod 0444 md4.el ||
echo 'restore of md4.el failed'
Wc_c="`wc -c < 'md4.el'`"
test 4010 -eq "$Wc_c" ||
echo 'md4.el: original size 4010, current size' "$Wc_c"
fi
exit 0
--
Johan Vromans jv@mh.nl via internet backbones
Multihouse Automatisering bv uucp: ..!{uunet,hp4nl}!mh.nl!jv
Doesburgweg 7, 2803 PL Gouda, The Netherlands phone/fax: +31 1820 62911/62500
------------------------ "Arms are made for hugging" -------------------------jv@mh.nl (Johan Vromans) (05/13/91)
In article <1991May11.143132.2114@pronto.mh.nl> jv@mh.nl (Johan Vromans) writes:
This file defines the functions to have automatic validation and
insertion of MD4 signatures using GNUS.
To use this, you also need the function add-hook. Here it is --
#!/bin/sh
# This is a shell archive (produced by shar 3.49)
# To extract the files from this archive, save it to a file, remove
# everything above the "!/bin/sh" line above, and type "sh file_name".
#
# made 05/13/1991 07:36 UTC by jv@largo
# Source directory /u1/users/jv
#
# existing files will NOT be overwritten unless -c is specified
#
# This shar contains:
# length mode name
# ------ ---------- ------------------------------------------
# 625 -rw-r--r-- add-hook.el
#
# ============= add-hook.el ==============
if test -f 'add-hook.el' -a X"$1" != X"-c"; then
echo 'x - skipping add-hook.el (File already exists)'
else
echo 'x - extracting add-hook.el (Text)'
sed 's/^X//' << 'SHAR_EOF' > 'add-hook.el' &&
X;; add-hook function by Dan LaLiberte <liberte@cs.uiuc.edu>
X(defun add-hook (hook-var hook-function)
X "Prepend to the value of HOOK-VAR the function HOOK-FUNCTION, if it
Xis not already an element.
Xhook-var's value may be a single function or a list of functions."
X (if (boundp hook-var)
X (let ((value (symbol-value hook-var)))
X (if (and (listp value) (not (eq (car value) 'lambda)))
X (and (not (memq hook-function value))
X (set hook-var
X (cons hook-function value)))
X (and (not (eq hook-function value))
X (set hook-var
X (list hook-function value)))))
X (set hook-var hook-function)
X ))
SHAR_EOF
chmod 0644 add-hook.el ||
echo 'restore of add-hook.el failed'
Wc_c="`wc -c < 'add-hook.el'`"
test 625 -eq "$Wc_c" ||
echo 'add-hook.el: original size 625, current size' "$Wc_c"
fi
exit 0
--
Johan Vromans jv@mh.nl via internet backbones
Multihouse Automatisering bv uucp: ..!{uunet,hp4nl}!mh.nl!jv
Doesburgweg 7, 2803 PL Gouda, The Netherlands phone/fax: +31 1820 62911/62500
------------------------ "Arms are made for hugging" -------------------------