[Mimedefang] mimedefang-filter config problem

[NFN Smith]

This will take a bit of explaining, so please bear with me.

I'm working with an up-line provider on implementing SpamAssassin and
MIMEDefang, and having problems with rewriting subject lines to include 
a SA score.

In this particular installation, we have MIMEDefang running with a lot
of customized routines that do extensive header rewriting.  The box in
question is running RH 7.3, sendmail 8.12.8-1, mimedefang-2.25-1 and
spamassassin-2.64-1, all of which have been installed from RPM
distributions.

What's happening is if we add the following to sub filter_end:

	action_change_header("Subject", "[SPAM: $hits] $Subject");

then running:

	perl -cw mimedefang-filter

we get the following response:

> Global symbol "$Subject" requires explicit package name at
> mimedefang-filter line 549. mimedefang-filter had compilation errors.

For this, line 549 is a comment line, where the previous line of active 
code is:

            if (-s "./INPUTMSG" < 100*1024) {

that is, the test to ignore a message if it's larger than 100K.  If we 
comment out the action_change_header line (as quoted above), the problem 
goes away.  In the same way, excluding $Subject from that line also 
makes the problem go away.

If I copy this mimedefang-filter file over to a different box (this one 
running Fedora Core-2, sendmail 8.13.1, mimedefang 2.44 and spamassassin 
2.64, all built from tarball), we get a different, but similar error:

> Global symbol "$Subject" requires explicit package name at
> /tmp/mimedefang-filter line 573, <DATA> line 225. /tmp/mimedefang-filter
> had compilation errors.

In this, line 225 is in the set of customized routines, and line 573 is 
the active 'action_change_header' line.  For reference, I've quoted the 
entirety of sub filter_end below (excluding comment lines). 
fen_post_filter is a call to one of our customized routines.

(The Fedora box has a different mimedefang-filter running, without all 
the customized header rewriting, and in the mimedefang-filter it runs, 
it has no problem with rewriting the subject line, using identical 
syntax with action_change_header.)

In this situation, why are we not able to get to the contents of 
$Subject?  How do we work around this problem?

Thanks in advance.

Smith


> sub filter_end ($) {
>     my($entity) = @_;
> 
>     # No sense doing any extra work
>     return if message_rejected();
> 
>     # Spam checks if SpamAssassin is installed
>     if ($Features{"SpamAssassin"}) {
>         if (-s "./INPUTMSG" < 100*1024) {
>             my($hits, $req, $names, $report) = spam_assassin_check();
>             if ($hits >= $req) {
>                 md_log('spam', $hits, $RelayAddr);
>                 my($score);
>                 if ($hits < 20) {
>                     $score = "*" x int($hits);
>                 } else {
>                     $score = "*" x 20;
>                 }
>                 action_change_header("X-Spam-Score", "$hits ($score) $names");
> 
>                 # If you find the SA report useful, add it, I guess...
>                 action_add_part($entity, "text/plain", "-suggest",
>                                 "$report\n",
>                                 "SpamAssassinReport.txt", "inline");
> #####           action_change_header("Subject", "[SPAM: $hits] $Subject");
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The problem line of code.

>                 action_add_header("X-Spam-Status", "Yes");
>             } else {
>                 # Delete any existing X-Spam-Score header?
>                 action_delete_header("X-Spam-Score");
>                 action_add_header("X-Spam-Status", "No");
>             }
>         }
>     }
>     fen_post_filter($entity);
> }

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