[Mimedefang] Why does my x-header appear more than once?
Mark Penkower
mark at roycenet.com
Wed Jun 23 15:06:30 EDT 2004
I added the follwoing code to my filter:
action_add_header("X-Spam-Checked-By", "Custom Spam Checking Rules");
When I send email to myself locally, the header only appears once. If I send email to myself from an external account, the header appears 2 or 3 times.
Why?
Do I have it in the wrong place in my filter?
I have included my filter - I apologize for any line breakes that my email client adds:
-*- Perl -*-
#***********************************************************************
#
# mimedefang-filter
#
# Suggested minimum-protection filter for Microsoft Windows clients, plus
# SpamAssassin checks if SpamAssassin is installed.
#
# Copyright (C) 2002 Roaring Penguin Software Inc.
#
# This program may be distributed under the terms of the GNU General
# Public License, Version 2, or (at your option) any later version.
#
# $Id: suggested-minimum-filter-for-windows-clients,v 1.72 2003/11/14 21:33:20 dfs Exp $
#***********************************************************************
#***********************************************************************
# Set administrator's e-mail address here. The administrator receives
# quarantine messages and is listed as the contact for site-wide
# MIMEDefang policy. A good example would be 'defang-admin at mydomain.com'
#***********************************************************************
$AdminAddress = 'mark at roycenet.com';
$AdminName = "Mark Penkower";
#***********************************************************************
# Set the e-mail address from which MIMEDefang quarantine warnings and
# user notifications appear to come. A good example would be
# 'mimedefang at mydomain.com'. Make sure to have an alias for this
# address if you want replies to it to work.
#***********************************************************************
$DaemonAddress = 'mimedefang at localhost';
#***********************************************************************
# If you set $AddWarningsInline to 1, then MIMEDefang tries *very* hard
# to add warnings directly in the message body (text or html) rather
# than adding a separate "WARNING.TXT" MIME part. If the message
# has no text or html part, then a separate MIME part is still used.
#***********************************************************************
$AddWarningsInline = 0;
#***********************************************************************
# To enable syslogging of virus and spam activity, add the following
# to the filter:
# md_graphdefang_log_enable();
# You may optionally provide a syslogging facility by passing an
# argument such as: md_graphdefang_log_enable('local4'); If you do this, be
# sure to setup the new syslog facility (probably in /etc/syslog.conf).
# An optional second argument causes a line of output to be produced
# for each recipient (if it is 1), or only a single summary line
# for all recipients (if it is 0.) The default is 1.
# Comment this line out to disable logging.
#***********************************************************************
md_graphdefang_log_enable('mail', 1);
#***********************************************************************
# Uncomment this to block messages with more than 50 parts. This will
# *NOT* work unless you're using Roaring Penguin's patched version
# of MIME tools, version MIME-tools-5.411a-RP-Patched-02 or later.
#
# WARNING: DO NOT SET THIS VARIABLE unless you're using at least
# MIME-tools-5.411a-RP-Patched-02; otherwise, your filter will fail.
#***********************************************************************
# $MaxMIMEParts = 50;
#***********************************************************************
# Set various stupid things your mail client does below.
#***********************************************************************
# Set the next one if your mail client cannot handle nested multipart
# messages. DO NOT set this lightly; it will cause action_add_part to
# work rather strangely. Leave it at zero, even for MS Outlook, unless
# you have serious problems.
$Stupidity{"flatten"} = 0;
# Set the next one if your mail client cannot handle multiple "inline"
# parts.
$Stupidity{"NoMultipleInlines"} = 0;
# The next lines force SpamAssassin modules to be loaded and rules
# to be compiled immediately. This may improve performance on busy
# mail servers. Comment the lines out if you don't like them.
#if ($Features{"SpamAssassin"}) {
# spam_assassin_init()->compile_now(1) if defined(spam_assassin_init());
# If you want to use auto-whitelisting:
# if (defined($SASpamTester)) {
# use Mail::SpamAssassin::DBBasedAddrList;
# my $awl = Mail::SpamAssassin::DBBasedAddrList->new();
# $SASpamTester->set_persistent_address_list_factory($awl) if defined($awl);
# }
#}
# This procedure returns true for entities with bad filenames.
sub filter_bad_filename ($) {
my($entity) = @_;
my($bad_exts, $re);
# Bad extensions
$bad_exts = '(ade|adp|app|asd|asf|asx|bas|bat|chm|cmd|com|cpl|crt|dll|exe|fxp|hlp|hta|hto|inf|ini|ins|isp||jar|js|jse|lib|lnk|mdb|mde|msc|msi|msp|mst|ocx|pcd|pif|prg|rar|reg|scr|sct|sh|shb|shs|sys|vb|vbe|vbs|vxd|wmd|wms|wsc|wsf|wsh|zls\{[^\}]+\})';
# Do not allow:
# - CLSIDs {foobarbaz}
# - bad extensions (possibly with trailing dots) at end
$re = '\.' . $bad_exts . '$';
return re_match($entity, $re);
}
# Scan for a virus using the first supported virus scanner we find.
sub message_contains_virus () {
# return message_contains_virus_avp() if ($Features{'Virus:AVP'});
# return message_contains_virus_fprot() if ($Features{'Virus:FPROT'});
# return message_contains_virus_fsav() if ($Features{'Virus:FSAV'});
# return message_contains_virus_hbedv() if ($Features{'Virus:HBEDV'});
# return message_contains_virus_nai() if ($Features{'Virus:NAI'});
# return message_contains_virus_bdc() if ($Features{'Virus:BDC'});
# return message_contains_virus_nvcc() if ($Features{'Virus:NVCC'});
# return message_contains_virus_rav() if ($Features{'Virus:RAV'});
# return message_contains_virus_sophie() if ($Features{'Virus:SOPHIE'});
# return message_contains_virus_trophie() if ($Features{'Virus:TROPHIE'});
# return message_contains_virus_sophos() if ($Features{'Virus:SOPHOS'});
# return message_contains_virus_trend() if ($Features{'Virus:TREND'});
# return message_contains_virus_filescan() if ($Features{'Virus:FileScan'});
# return message_contains_virus_clamd() if ($Features{'Virus:CLAMD'});
# return message_contains_virus_clamav() if ($Features{'Virus:CLAMAV'});
# return message_contains_virus_carrier_scan() if ($Features{'Virus:SymantecCSS'});
# return (wantarray ? (0, 'ok', 'ok') : 0);
}
# Scan for a virus using the first supported virus scanner we find.
sub entity_contains_virus ($) {
# my($e) = @_;
# return entity_contains_virus_avp($e) if ($Features{'Virus:AVP'});
# return entity_contains_virus_fprot($e) if ($Features{'Virus:FPROT'});
# return entity_contains_virus_fsav($e) if ($Features{'Virus:FSAV'});
# return entity_contains_virus_hbedv($e) if ($Features{'Virus:HBEDV'});
# return entity_contains_virus_nai($e) if ($Features{'Virus:NAI'});
# return entity_contains_virus_bdc($e) if ($Features{'Virus:BDC'});
# return entity_contains_virus_nvcc($e) if ($Features{'Virus:NVCC'});
# return entity_contains_virus_rav($e) if ($Features{'Virus:RAV'});
# return entity_contains_virus_sophie($e) if ($Features{'Virus:SOPHIE'});
# return entity_contains_virus_trophie($e) if ($Features{'Virus:TROPHIE'});
# return entity_contains_virus_sophos($e) if ($Features{'Virus:SOPHOS'});
# return entity_contains_virus_trend($e) if ($Features{'Virus:TREND'});
# return entity_contains_virus_filescan($e) if ($Features{'Virus:FileScan'});
# return entity_contains_virus_clamd($e) if ($Features{'Virus:CLAMD'});
# return entity_contains_virus_clamav($e) if ($Features{'Virus:CLAMAV'});
# return entity_contains_virus_carrier_scan($e) if ($Features{'Virus:SymantecCSS'});
# return (wantarray ? (0, 'ok', 'ok') : 0);
}
#***********************************************************************
# %PROCEDURE: filter_begin
# %ARGUMENTS:
# None
# %RETURNS:
# Nothing
# %DESCRIPTION:
# Called just before e-mail parts are processed
#***********************************************************************
sub filter_begin () {
# ALWAYS drop messages with suspicious chars in headers
# if ($SuspiciousCharsInHeaders) {
# md_graphdefang_log('suspicious_chars');
# action_quarantine_entire_message("Message quarantined because of suspicious characters in headers");
# Do NOT allow message to reach recipient(s)
# return action_discard();
# }
# Scan for viruses if any virus-scanners are installed
# my($code, $category, $action) = message_contains_virus();
# Lower level of paranoia - only looks for actual viruses
# $FoundVirus = ($category eq "virus");
# Higher level of paranoia - takes care of "suspicious" objects
# $FoundVirus = ($action eq "quarantine");
# if ($action eq "tempfail") {
# action_tempfail("Problem running virus-scanner");
# md_syslog('warning', "Problem running virus scanner: code=$code, category=$category, action=$action");
# }
}
#***********************************************************************
# %PROCEDURE: filter
# %ARGUMENTS:
# entity -- a Mime::Entity object (see MIME-tools documentation for details)
# fname -- the suggested filename, taken from the MIME Content-Disposition:
# header. If no filename was suggested, then fname is ""
# ext -- the file extension (everything from the last period in the name
# to the end of the name, including the period.)
# type -- the MIME type, taken from the Content-Type: header.
#
# NOTE: There are two likely and one unlikely place for a filename to
# appear in a MIME message: In Content-Disposition: filename, in
# Content-Type: name, and in Content-Description. If you are paranoid,
# you will use the re_match and re_match_ext functions, which return true
# if ANY of these possibilities match. re_match checks the whole name;
# re_match_ext checks the extension. See the sample filter below for usage.
# %RETURNS:
# Nothing
# %DESCRIPTION:
# This function is called once for each part of a MIME message.
# There are many action_*() routines which can decide the fate
# of each part; see the mimedefang-filter man page.
#***********************************************************************
sub filter ($$$$) {
my($entity, $fname, $ext, $type) = @_;
return if message_rejected(); # Avoid unnecessary work
# Block message/partial parts
# if (lc($type) eq "message/partial") {
# md_graphdefang_log('message/partial');
# action_bounce("MIME type message/partial not accepted here");
# return action_discard();
# }
# Virus scan
# if ($FoundVirus) {
# my($code, $category, $action);
# $VirusScannerMessages = "";
# ($code, $category, $action) = entity_contains_virus($entity);
# # If you are more paranoid, change to: if ($action eq "quarantine") {
# if ($category eq "virus") {
# md_graphdefang_log('virus',$VirusName, $RelayAddr);
# Bounce the mail!
# action_bounce("Virus $VirusName found in mail - rejected");
# But quarantine the part for examination later. Comment
# the next line out if you don't want to bother.
# action_quarantine($entity, "A known virus was discovered and deleted. Virus-scanner messages follow:\n$VirusScannerMessages\n\n");
#
# return;
# }
# if ($action eq "tempfail") {
# action_tempfail("Problem running virus-scanner");
# md_syslog('warning', "Problem running virus scanner: code=$code, category=$category, action=$action");
# }
# }
if (filter_bad_filename($entity)) {
md_graphdefang_log('bad_filename', $fname, $type);
action_bounce("We are not acepting attachments of this type");
action_notify_administrator("The Mailserver bounced a message.\n");
}
# eml is bad if it's not multipart
# if (re_match($entity, '\.eml')) {
# md_graphdefang_log('non_multipart');
# return action_quarantine($entity, "A non-multipart attachment named $fname was removed from this document as it\nconstituted a security hazard. If you require this document, please contact\nthe sender and arrange an alternate means of receiving it.\n");
# }
# Clean up HTML if Anomy::HTMLCleaner is installed.
# if ($Features{"HTMLCleaner"}) {
# if ($type eq "text/html") {
# return anomy_clean_html($entity);
# }
# }
action_add_header("X-Spam-Checked-By", "Custom Spam Checking Rules");
return action_accept();
}
#***********************************************************************
# %PROCEDURE: filter_multipart
# %ARGUMENTS:
# entity -- a Mime::Entity object (see MIME-tools documentation for details)
# fname -- the suggested filename, taken from the MIME Content-Disposition:
# header. If no filename was suggested, then fname is ""
# ext -- the file extension (everything from the last period in the name
# to the end of the name, including the period.)
# type -- the MIME type, taken from the Content-Type: header.
# %RETURNS:
# Nothing
# %DESCRIPTION:
# This is called for multipart "container" parts such as message/rfc822.
# You cannot replace the body (because multipart parts have no body),
# but you should check for bad filenames.
#***********************************************************************
sub filter_multipart ($$$$) {
# my($entity, $fname, $ext, $type) = @_;
#
# if (filter_bad_filename($entity)) {
# md_graphdefang_log('bad_filename', $fname, $type);
# action_notify_administrator("A MULTIPART attachment of type $type, named $fname was dropped.\n");
# return action_drop_with_warning("An attachment of type $type, named $fname was removed from this document as it\nconstituted a security hazard. If you require this document, please contact\nthe sender and arrange an alternate means of receiving it.\n");
# }
# eml is bad if it's not message/rfc822
# if (re_match($entity, '\.eml') and ($type ne "message/rfc822")) {
# md_graphdefang_log('non_rfc822',$fname);
# return action_drop_with_warning("A non-message/rfc822 attachment named $fname was removed from this document as it\nconstituted a security hazard. If you require this document, please contact\nthe sender and arrange an alternate means of receiving it.\n");
# }
# Block message/partial parts
# if (lc($type) eq "message/partial") {
# md_graphdefang_log('message/partial');
# action_bounce("MIME type message/partial not accepted here");
# return;
}
# return action_accept();
#}
#***********************************************************************
# %PROCEDURE: defang_warning
# %ARGUMENTS:
# oldfname -- the old file name of an attachment
# fname -- the new "defanged" name
# %RETURNS:
# A warning message
# %DESCRIPTION:
# This function customizes the warning message when an attachment
# is defanged.
#***********************************************************************
sub defang_warning ($$) {
# my($oldfname, $fname) = @_;
# return
# "An attachment named '$oldfname' was converted to '$fname'.\n" .
# "To recover the file, right-click on the attachment and Save As\n" .
# "'$oldfname'\n";
}
# If SpamAssassin found SPAM, append report. We do it as a separate
# attachment of type text/plain
sub filter_end ($) {
my($entity) = @_;
# If you want quarantine reports, uncomment next line
# send_quarantine_notifications();
# IMPORTANT NOTE: YOU MUST CALL send_quarantine_notifications() AFTER
# ANY PARTS HAVE BEEN QUARANTINED. SO IF YOU MODIFY THIS FILTER TO
# QUARANTINE SPAM, REWORK THE LOGIC TO CALL send_quarantine_notifications()
# AT THE END!!!
# No sense doing any extra work
return if message_rejected();
# Spam checks if SpamAssassin is installed
if ($Features{"SpamAssassin"}) {
if (-s "./INPUTMSG" < 100*1024) {
# Only scan messages smaller than 100kB. Larger messages
# are extremely unlikely to be spam, and SpamAssassin is
# dreadfully slow on very large messages.
my($hits, $req, $names, $report) = spam_assassin_check();
my($score);
if ($hits < 40) {
$score = "*" x int($hits);
} else {
$score = "*" x 40;
}
# We add a header which looks like this:
# X-Spam-Score: 6.8 (******) NAME_OF_TEST,NAME_OF_TEST
# The number of asterisks in parens is the integer part
# of the spam score clamped to a maximum of 40.
# MUA filters can easily be written to trigger on a
# minimum number of asterisks...
if ($hits >= $req) {
action_change_header("X-Spam-Score", "$hits ($score) $names");
md_graphdefang_log('spam', $hits, $RelayAddr);
# If you find the SA report useful, add it, I guess...
action_add_part($entity, "text/plain", "-suggest",
"$report\n",
"SpamAssassinReport.txt", "inline");
} else {
# Delete any existing X-Spam-Score header?
action_delete_header("X-Spam-Score");
}
}
}
# I HATE HTML MAIL! If there's a multipart/alternative with both
# text/plain and text/html parts, nuke the text/html. Thanks for
# wasting our disk space and bandwidth...
# If you don't mind HTML mail, comment out the next line.
# remove_redundant_html_parts($entity);
md_graphdefang_log('mail_in');
}
sub filter_end {
# my($entity) = @_;
# append_text_boilerplate($entity,
# "We are not laible", 0);
# append_html_boilerplate($entity,
# "<em>We</em> Are not liable", 0);
}
# DO NOT delete the next line, or Perl will complain.
1;
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