emacs/lisp/mh-e/mh-junk.el

;;; mh-junk.el --- Interface to anti-spam measures

;; Copyright (C) 2003, 2004 Free Software Foundation, Inc.

;; Author: Satyaki Das <satyaki@theforce.stanford.edu>,
;;         Bill Wohler <wohler@newt.com>
;; Maintainer: Bill Wohler <wohler@newt.com>
;; Keywords:  mail, spam

;; 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:

;; Spam handling in MH-E.

;;; Change Log:

;;; Code:

(eval-when-compile (require 'mh-acros))
(mh-require-cl)
(require 'mh-e)

;; Interactive functions callable from the folder buffer
;;;###mh-autoload
(defun mh-junk-blacklist (range)
  "Blacklist RANGE as spam.

This command trains the spam program in use (see the `mh-junk-program' option)
with the content of the range (see `mh-interactive-range') and then handles
the message(s) as specified by the `mh-junk-disposition' option.

For more information about using your particular spam fighting program, see:

  - `mh-spamassassin-blacklist'
  - `mh-bogofilter-blacklist'
  - `mh-spamprobe-blacklist'"
  (interactive (list (mh-interactive-range "Blacklist")))
  (let ((blacklist-func (nth 1 (assoc mh-junk-choice mh-junk-function-alist))))
    (unless blacklist-func
      (error "Customize `mh-junk-program' appropriately"))
    (let ((dest (cond ((null mh-junk-disposition) nil)
                      ((equal mh-junk-disposition "") "+")
                      ((eq (aref mh-junk-disposition 0) ?+)
                       mh-junk-disposition)
                      ((eq (aref mh-junk-disposition 0) ?@)
                       (concat mh-current-folder "/"
                               (substring mh-junk-disposition 1)))
                      (t (concat "+" mh-junk-disposition)))))
      (mh-iterate-on-range msg range
        (message (format "Blacklisting message %d..." msg))
        (funcall (symbol-function blacklist-func) msg)
        (message (format "Blacklisting message %d...done" msg))
        (if (not (memq msg mh-seen-list))
            (setq mh-seen-list (cons msg mh-seen-list)))
        (if dest
            (mh-refile-a-msg nil (intern dest))
          (mh-delete-a-msg nil)))
      (mh-next-msg))))

;;;###mh-autoload
(defun mh-junk-whitelist (range)
  "Whitelist RANGE as ham.

This command reclassifies a range of messages (see `mh-interactive-range') as
ham if it were incorrectly classified as spam. It then refiles the message
into the `+inbox' folder.

The `mh-junk-program' option specifies the spam program in use."
  (interactive (list (mh-interactive-range "Whitelist")))
  (let ((whitelist-func (nth 2 (assoc mh-junk-choice mh-junk-function-alist))))
    (unless whitelist-func
      (error "Customize `mh-junk-program' appropriately"))
    (mh-iterate-on-range msg range
      (message (format "Whitelisting message %d..." msg))
      (funcall (symbol-function whitelist-func) msg)
      (message (format "Whitelisting message %d...done" msg))
      (mh-refile-a-msg nil (intern mh-inbox)))
    (mh-next-msg)))



;; Spamassassin Interface

(defvar mh-spamassassin-executable (executable-find "spamassassin"))
(defvar mh-sa-learn-executable (executable-find "sa-learn"))

(defun mh-spamassassin-blacklist (msg)
  "Blacklist MSG with SpamAssassin.

SpamAssassin is one of the more popular spam filtering programs. Get it from
your local distribution or from http://spamassassin.org/.

To use SpamAssassin, add the following recipes to `.procmailrc':

    MAILDIR=$HOME/`mhparam Path`

    # Fight spam with SpamAssassin.
    :0fw
    | spamc

    # Anything with a spam level of 10 or more is junked immediately.
    :0:
    * ^X-Spam-Level: ..........
    /dev/null

    :0:
    * ^X-Spam-Status: Yes
    spam/.

If you don't use `spamc', use `spamassassin -P -a'.

Note that one of the recipes above throws away messages with a score greater
than or equal to 10. Here's how you can determine a value that works best for
you.

First, run `spamassassin -t' on every mail message in your archive and use
Gnumeric to verify that the average plus the standard deviation of good mail
is under 5, the SpamAssassin default for \"spam\".

Using Gnumeric, sort the messages by score and view the messages with the
highest score. Determine the score which encompasses all of your interesting
messages and add a couple of points to be conservative. Add that many dots to
the `X-Spam-Level:' header field above to send messages with that score down
the drain.

In the example above, messages with a score of 5-9 are set aside in the
`+spam' folder for later review. The major weakness of rules-based filters is
a plethora of false positives so it is worthwhile to check.

If SpamAssassin classifies a message incorrectly, or is unsure, you can use
the MH-E commands \\[mh-junk-blacklist] and \\[mh-junk-whitelist].

The \\[mh-junk-blacklist] command adds a `blacklist_from' entry to
`~/spamassassin/user_prefs', deletes the message, and sends the message to the
Razor, so that others might not see this spam. If the `sa-learn' command is
available, the message is also recategorized as spam.

The \\[mh-junk-whitelist] command adds a `whitelist_from' rule to the
`~/.spamassassin/user_prefs' file. If the `sa-learn' command is available, the
message is also recategorized as ham.

Over time, you'll observe that the same host or domain occurs repeatedly in
the `blacklist_from' entries, so you might think that you could avoid future
spam by blacklisting all mail from a particular domain. The utility function
`mh-spamassassin-identify-spammers' helps you do precisely that. This function
displays a frequency count of the hosts and domains in the `blacklist_from'
entries from the last blank line in `~/.spamassassin/user_prefs' to the end of
the file. This information can be used so that you can replace multiple
`blacklist_from' entries with a single wildcard entry such as:

    blacklist_from *@*amazingoffersdirect2u.com

In versions of SpamAssassin (2.50 and on) that support a Bayesian classifier,
\\[mh-junk-blacklist] uses the `sa-learn' program to recategorize the message
as spam. Neither MH-E, nor SpamAssassin, rebuilds the database after adding
words, so you will need to run `sa-learn --rebuild' periodically. This can be
done by adding the following to your crontab:

    0 * * * *	sa-learn --rebuild > /dev/null 2>&1"
  (unless mh-spamassassin-executable
    (error "Unable to find the spamassassin executable"))
  (let ((current-folder mh-current-folder)
        (msg-file (mh-msg-filename msg mh-current-folder))
        (sender))
    (save-excursion
      (message (format "Reporting message %d..." msg))
      (mh-truncate-log-buffer)
      (call-process mh-spamassassin-executable msg-file mh-log-buffer nil
                    ;;"--report" "--remove-from-whitelist"
                    "-r" "-R")          ; spamassassin V2.20
      (when mh-sa-learn-executable
          (message "Recategorizing this message as spam...")
          (call-process mh-sa-learn-executable msg-file mh-log-buffer nil
                        "--single" "--spam" "--local" "--no-rebuild"))
      (message (format "Blacklisting message %d..." msg))
      (set-buffer (get-buffer-create mh-temp-buffer))
      (erase-buffer)
      (call-process (expand-file-name mh-scan-prog mh-progs)
                    nil mh-junk-background nil
                    (format "%s" msg) current-folder
                    "-format" "%<(mymbox{from})%|%(addr{from})%>")
      (goto-char (point-min))
      (if (search-forward-regexp "^\\(.+\\)$" nil t)
          (progn
            (setq sender (match-string 0))
            (mh-spamassassin-add-rule "blacklist_from" sender)
            (message (format "Blacklisting message %d...done" msg)))
        (message (format "Blacklisting message %d...not done (from my address)" msg))))))

(defun mh-spamassassin-whitelist (msg)
  "Whitelist MSG with SpamAssassin.

The \\[mh-junk-whitelist] command adds a `whitelist_from' rule to the
`~/.spamassassin/user_prefs' file. If the `sa-learn' command is available, the
message is also recategorized as ham.

See `mh-spamassassin-blacklist' for more information."
  (unless mh-spamassassin-executable
    (error "Unable to find the spamassassin executable"))
  (let ((msg-file (mh-msg-filename msg mh-current-folder))
        (show-buffer (get-buffer mh-show-buffer))
        from)
    (save-excursion
      (set-buffer (get-buffer-create mh-temp-buffer))
      (erase-buffer)
      (message "Removing spamassassin markup from message...")
      (call-process mh-spamassassin-executable msg-file mh-temp-buffer nil
                    ;; "--remove-markup"
                    "-d")               ; spamassassin V2.20
      (if show-buffer
          (kill-buffer show-buffer))
      (write-file msg-file)
      (when mh-sa-learn-executable
        (message "Recategorizing this message as ham...")
        (call-process mh-sa-learn-executable msg-file mh-temp-buffer nil
                      "--single" "--ham" "--local --no-rebuild"))
      (message (format "Whitelisting message %d..." msg))
      (setq from
            (car (mh-funcall-if-exists
                  ietf-drums-parse-address (mh-get-header-field "From:"))))
      (kill-buffer nil)
      (unless (or (null from) (equal from ""))
        (mh-spamassassin-add-rule "whitelist_from" from))
      (message (format "Whitelisting message %d...done" msg)))))

(defun mh-spamassassin-add-rule (rule body)
  "Add a new rule to `~/.spamassassin/user_prefs'.
The name of the rule is RULE and its body is BODY."
  (save-window-excursion
    (let* ((line (format "%s\t%s\n" rule body))
           (case-fold-search t)
           (file (expand-file-name "~/.spamassassin/user_prefs"))
           (buffer-exists (find-buffer-visiting file)))
      (find-file file)
      (if (not (search-forward (format "\n%s" line) nil t))
          (progn
            (goto-char (point-max))
            (insert (if (bolp) "" "\n") line)
            (save-buffer)))
      (if (not buffer-exists)
          (kill-buffer nil)))))

(defun mh-spamassassin-identify-spammers ()
  "Identify spammers who are repeat offenders.

This function displays a frequency count of the hosts and domains in the
`blacklist_from' entries from the last blank line in
`~/.spamassassin/user_prefs' to the end of the file. This information can be
used so that you can replace multiple `blacklist_from' entries with a single
wildcard entry such as:

    blacklist_from *@*amazingoffersdirect2u.com"
  (interactive)
  (let* ((file (expand-file-name "~/.spamassassin/user_prefs"))
         (domains (make-hash-table :test 'equal)))
    (find-file file)
    ;; Only consider entries between last blank line and end of file.
    (goto-char (1- (point-max)))
    (search-backward-regexp "^$")
    ;; Perform frequency count.
    (save-excursion
      (while (search-forward-regexp "^blacklist_from\\s-*\\(.*\\)@\\(.*\\)$"
                                    nil t)
        (let ((host (match-string 2))
              value)
          ;; Remove top-level-domain from hostname.
          (setq host (cdr (reverse (split-string host "\\."))))
          ;; Add counts for each host and domain part.
          (while host
            (setq value (gethash (car host) domains))
            (setf (gethash (car host) domains) (1+ (if (not value) 0 value)))
            (setq host (cdr host))))))

    ;; Output
    (delete-other-windows)
    (pop-to-buffer (get-buffer-create "*MH-E Spammer Frequencies*"))
    (erase-buffer)
    (maphash '(lambda (key value) ""
                (if (> value 2)
                    (insert (format "%s %s\n" key value))))
             domains)
    (sort-numeric-fields 2 (point-min) (point-max))
    (reverse-region (point-min) (point-max))
    (goto-char (point-min))))



;; Bogofilter Interface

(defvar mh-bogofilter-executable (executable-find "bogofilter"))

(defun mh-bogofilter-blacklist (msg)
  "Blacklist MSG with Bogofilter.

Bogofilter is a Bayesian spam filtering program. Get it from your local
distribution or from http://bogofilter.sourceforge.net/.

Bogofilter is taught by running:

    bogofilter -n < good-message

on every good message, and

    bogofilter -s < spam-message

on every spam message. This is called a full training; three other
training methods are described in the FAQ that is distributed with bogofilter.
Note that most Bayesian filters need 1000 to 5000 of each type of message to
start doing a good job.

To use Bogofilter, add the following recipes to `.procmailrc':

    MAILDIR=$HOME/`mhparam Path`

    # Fight spam with Bogofilter.
    :0fw
    | bogofilter -3 -e -p

    :0:
    * ^X-Bogosity: Yes, tests=bogofilter
    spam/.

    :0:
    * ^X-Bogosity: Unsure, tests=bogofilter
    spam/unsure/.

If Bogofilter classifies a message incorrectly, or is unsure, you can use the
MH-E commands \\[mh-junk-blacklist] and \\[mh-junk-whitelist] to update
Bogofilter's training.

The \"Bogofilter FAQ\" suggests that you run the following
occasionally to shrink the database:

    bogoutil -d wordlist.db | bogoutil -l wordlist.db.new
    mv wordlist.db wordlist.db.prv
    mv wordlist.db.new wordlist.db

The \"Bogofilter tuning HOWTO\" describes how you can fine-tune Bogofilter."
  (unless mh-bogofilter-executable
    (error "Unable to find the bogofilter executable"))
  (let ((msg-file (mh-msg-filename msg mh-current-folder)))
    (call-process mh-bogofilter-executable msg-file mh-junk-background
                  nil "-s")))

(defun mh-bogofilter-whitelist (msg)
  "Whitelist MSG with Bogofilter.

See `mh-bogofilter-blacklist' for more information."
  (unless mh-bogofilter-executable
    (error "Unable to find the bogofilter executable"))
  (let ((msg-file (mh-msg-filename msg mh-current-folder)))
    (call-process mh-bogofilter-executable msg-file mh-junk-background
                  nil "-n")))



;; Spamprobe Interface

(defvar mh-spamprobe-executable (executable-find "spamprobe"))

(defun mh-spamprobe-blacklist (msg)
  "Blacklist MSG with SpamProbe.

SpamProbe is a Bayesian spam filtering program. Get it from your local
distribution or from http://spamprobe.sourceforge.net.

To use SpamProbe, add the following recipes to `.procmailrc':

    MAILDIR=$HOME/`mhparam Path`

    # Fight spam with SpamProbe.
    :0
    SCORE=| spamprobe receive

    :0 wf
    | formail -I \"X-SpamProbe: $SCORE\"

    :0:
    *^X-SpamProbe: SPAM
    spam/.

If SpamProbe classifies a message incorrectly, you can use the MH-E commands
\\[mh-junk-blacklist] and \\[mh-junk-whitelist] to update SpamProbe's
training."
  (unless mh-spamprobe-executable
    (error "Unable to find the spamprobe executable"))
  (let ((msg-file (mh-msg-filename msg mh-current-folder)))
    (call-process mh-spamprobe-executable msg-file mh-junk-background
                  nil "spam")))

(defun mh-spamprobe-whitelist (msg)
  "Whitelist MSG with SpamProbe.

See `mh-spamprobe-blacklist' for more information."
  (unless mh-spamprobe-executable
    (error "Unable to find the spamprobe executable"))
  (let ((msg-file (mh-msg-filename msg mh-current-folder)))
    (call-process mh-spamprobe-executable msg-file mh-junk-background
                  nil "good")))

(provide 'mh-junk)

;;; Local Variables:
;;; indent-tabs-mode: nil
;;; sentence-end-double-space: nil
;;; End:

;;; arch-tag: 603335f1-77ff-4306-8828-5d3dad51abe1
;;; mh-junk.el ends here