null "Clean Header" multi-times gags sendmail

[Jeff A. Earickson]

Julian,

Setup:
------
Solaris 8, sendmail 8.12.5, mailscanner 3.22-7, Sophos, spamassassin

MailScanner Config Setting that triggers the problem:
-----------------------------------------------------
Changing the mailscanner.conf line
   Clean Header       = Found to be clean
to just be
   Clean Header       =
ie, nothing after the equals sign.  Putting something after the
equals sign fixes the problem, but there's a bug here.

The Problem:
------------
Running a piece of email thru mailscanner multiple times
with a blank "clean header" setup causes sendmail to give the following
syslog complaints:

SYSERR(root): readqf: ./qf.....: incomplete queue file read

Any piece of email in /var/spool/mqueue generating this complaint will
not be delivered by sendmail, but just sit there -- stuck.

Analysis:
---------
I spent some time staring at the qf files for multi-scanned messages
that ended up in /var/spool/mqueue, for both messages with a blank and
nonblank "Clean Header" settings.  For a blank "Clean Header" line,
the bottom of the qf file looked like:

H??X-MailScanner: , .

For a qf file with a nonblank "Clean Header = ftbc" line, the bottom of the
file looked like:

H??X-MailScanner: ftbc, ftbc
.

Note the placement of the period, which signifies to sendmail where the
end of the qf file is supposed to be.  For the blank header, it does not
end up by itself as the last line, hence sendmail complains that the queue
file is incomplete.  I found that I could unjam the problem qf files in
my queue by editing them and sticking a period at the bottom, then
rerunning the queue on that message by hand to get it delivered.  And
of course I can chase this problem away by making sure that "Clean
Header" is not empty.  But this looks like a mailscanner bug -- it puts
the final period in the wrong place for multi-scanned messages and an
empty "clean headers" setting.

** Jeff A. Earickson, Ph.D                         PHONE: 207-872-3659
** Senior UNIX Sysadmin, Information Technology    EMAIL: jaearick at colby.edu
** Colby College, 4214 Mayflower Hill,               FAX: 207-872-3076
** Waterville ME, 04901-8842
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