"Banned Content" question - possibly a Web Bug code problem

Quentin Campbell Q.G.Campbell at NEWCASTLE.AC.UK
Thu Jan 13 08:50:25 GMT 2005


Julian

You had already given me a new SMDiskStore.pm module, dated 16 December
to try. The locking code in this differs from the new code you want me
to try as follows:

<   #JKF MailScanner::Lock::unlockclose($this->{indhandle});
<   close($this->{indhandle});
---
>   # Now we lock the df file as well, we must unlock it too.
>   MailScanner::Lock::unlockclose($this->{indhandle});
>   #close($this->{indhandle});

I have made the change as above and will let you know what happens. I
also note that the new code is in the MailScanner-4.37.7-1
SMDiskStore.pm which I was planning to move to anyway.

I have not touched the "Allow WebBugs = disarm" setting which I assume
is an essential part of the test of the changes to SMDiskStore.pm.

Quentin
---
PHONE: +44 191 222 8209    Information Systems and Services (ISS),
                           University of Newcastle,
                           Newcastle upon Tyne,
FAX:   +44 191 222 8765    United Kingdom, NE1 7RU.
------------------------------------------------------------------------
"Any opinion expressed above is mine. The University can get its own."  

>-----Original Message-----
>From: MailScanner mailing list 
>[mailto:MAILSCANNER at JISCMAIL.AC.UK] On Behalf Of Julian Field
>Sent: 12 January 2005 16:02
>To: MAILSCANNER at JISCMAIL.AC.UK
>Subject: Re: "Banned Content" question - possibly a Web Bug 
>code problem
>
>In which case try editing SMDiskStore.pm and replace the sub Lock and
>sub Unlock with this code:
>
># Open and lock the message
>sub Lock {
>  my $this = shift;
>
>  #print STDERR "About to lock " . $this->{hpath} . " and " .
>  #             $this->{dpath} . "\n";
>  MailScanner::Lock::openlock($this->{inhhandle}, '+<' . 
>$this->{hpath},
>'w', 'quiet')
>    or return undef;
>  #print STDERR "Got hlock\n";
>
>  # If locking the dfile fails, then must close and unlock the 
>qffile too
>  # 14/12/2004 Try putting this back in for now.
>  unless (MailScanner::Lock::openlock($this->{indhandle},
>                     '+<' . $this->{dpath}, 'w', 'quiet')) {
>        #JKF 14/12/2004 open($this->{indhandle}, '+<' . 
>$this->{dpath})) {
>    MailScanner::Lock::unlockclose($this->{inhhandle});
>    return undef;
>  }
>  #print STDERR "Got dlock\n";
>  return undef unless $this->{inhhandle} && $this->{indhandle};
>  return 1;
>}
>
>
># Close and unlock the message
>sub Unlock {
>  my $this = shift;
>
>  # Now we lock the df file as well, we must unlock it too.
>  MailScanner::Lock::unlockclose($this->{indhandle});
>  #close($this->{indhandle});
>  MailScanner::Lock::unlockclose($this->{inhhandle});
>}
>
>
>
>Quentin Campbell wrote:
>
>>Julian
>>
>>The version of MailScanner on which I have seen the problem 
>is 4.35.10.
>>
>>Quentin
>>---
>>PHONE: +44 191 222 8209    Information Systems and Services (ISS),
>>                           University of Newcastle,
>>                           Newcastle upon Tyne,
>>FAX:   +44 191 222 8765    United Kingdom, NE1 7RU.
>>--------------------------------------------------------------
>----------
>>"Any opinion expressed above is mine. The University can get its own."
>>
>>
>>
>>>-----Original Message-----
>>>From: MailScanner mailing list
>>>[mailto:MAILSCANNER at JISCMAIL.AC.UK] On Behalf Of Julian Field
>>>Sent: 12 January 2005 15:30
>>>To: MAILSCANNER at JISCMAIL.AC.UK
>>>Subject: Re: "Banned Content" question - possibly a Web Bug
>>>code problem
>>>
>>>What version of MailScanner are you using? I slightly improved the
>>>locking code (took out an "improvement" I made a long time 
>ago which I
>>>only made after lots of people requested it) in 4.37. It now 
>locks the
>>>df as well as the qf, which slows down delivery slightly in some
>>>situations, but appears to be more reliable than just locking the qf.
>>>
>>>Quentin Campbell wrote:
>>>
>>>
>>>
>>>>>-----Original Message-----
>>>>>From: MailScanner mailing list
>>>>>[mailto:MAILSCANNER at JISCMAIL.AC.UK] On Behalf Of Mike
>>>>>Sent: 12 January 2005 11:53
>>>>>To: MAILSCANNER at JISCMAIL.AC.UK
>>>>>Subject: Re: "Banned Content" question - a related problem
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>>From: MailScanner mailing list
>>>>>>
>>>>>>
>>>[mailto:MAILSCANNER at JISCMAIL.AC.UK] On
>>>
>>>
>>>>>>Behalf Of Quentin Campbell
>>>>>>
>>>>>>All the systems are now up2date as far as RH AS 3 patches are
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>concerned.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>>All the systems use the Sendmail that comes with these
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>system; the last
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>>time they were updated this was Sendmail 8.12.11. I use 
>the default
>>>>>>locking in MailScanner.
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>I also had this problem on sendmail 8.12.10. After changing
>>>>>the locking to posix, the problem was gone. So, although the
>>>>>docs state that the locking problem occurs only from 8.13 on,
>>>>>it seems that also some 8.12 versions are affected. Please set
>>>>>the locking mechanism to "posix" and see if it solves your problem.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>I will do this as a last resort. There are four reasons why 
>I want to
>>>>investigate other things first. In particular I want to capture a
>>>>message before then after it has gone through MailSanner and got
>>>>corrupted:
>>>>
>>>>1. Locking works OK on RH AS 3 systems with an up-to-date kernel.
>>>>2. The symptoms we are seeing do not appear to be repeatable so far
>>>>which makes conclusive testing difficult.
>>>>3. I have looked for other evidence of locking problems but
>>>>
>>>>
>>>cannot find
>>>
>>>
>>>>any. For example I can show that all messages tagged as spam by
>>>>MailScanner have been tagged once only. If there is a 
>locking problem
>>>>you will see the same message (ie. same Sendmail QID) being 
>tagged as
>>>>spam more than once by two or more MS processes.
>>>>4. The problem appears related to the Web Bug check. I will
>>>>
>>>>
>>>switch that
>>>
>>>
>>>>off first. See below for more details of this.
>>>>
>>>>Having looked further at the problem it appears to be 
>related to MIME
>>>>multipart/alternative messages having all or part of the HTML part
>>>>corrupted. The text part is not being affected.
>>>>
>>>>In all of the cases the logs show that MailScanner has 
>"disarmed" the
>>>>HTML content. Since I only "disarm" Web Bugs it appears 
>that there may
>>>>be a bug in the Web Bugs code that causes an intermittent
>>>>
>>>>
>>>problem. This
>>>
>>>
>>>>suspicion is reinforced by the observation that the problem 
>appears to
>>>>have started when I enabled the Web Bug check late last year. I will
>>>>first of all try "Allow WebBugs = yes" and see what happens.
>>>>
>>>>Quentin
>>>>
>>>>------------------------ MailScanner list ------------------------
>>>>To unsubscribe, email jiscmail at jiscmail.ac.uk with the words:
>>>>'leave mailscanner' in the body of the email.
>>>>Before posting, read the MAQ (http://www.mailscanner.biz/maq/) and
>>>>the archives (http://www.jiscmail.ac.uk/lists/mailscanner.html).
>>>>
>>>>Support MailScanner development - buy the book off the website!
>>>>
>>>>
>>>>
>>>>
>>>>
>>>--
>>>Julian Field
>>>www.MailScanner.info
>>>Buy the MailScanner book at www.MailScanner.info/store
>>>
>>>PGP footprint: EE81 D763 3DB0 0BFD E1DC 7222 11F6 5947 1415 B654
>>>
>>>------------------------ MailScanner list ------------------------
>>>To unsubscribe, email jiscmail at jiscmail.ac.uk with the words:
>>>'leave mailscanner' in the body of the email.
>>>Before posting, read the MAQ (http://www.mailscanner.biz/maq/) and
>>>the archives (http://www.jiscmail.ac.uk/lists/mailscanner.html).
>>>
>>>Support MailScanner development - buy the book off the website!
>>>
>>>
>>>
>>>
>>
>>------------------------ MailScanner list ------------------------
>>To unsubscribe, email jiscmail at jiscmail.ac.uk with the words:
>>'leave mailscanner' in the body of the email.
>>Before posting, read the MAQ (http://www.mailscanner.biz/maq/) and
>>the archives (http://www.jiscmail.ac.uk/lists/mailscanner.html).
>>
>>Support MailScanner development - buy the book off the website!
>>
>>
>>
>
>--
>Julian Field
>www.MailScanner.info
>Buy the MailScanner book at www.MailScanner.info/store
>
>PGP footprint: EE81 D763 3DB0 0BFD E1DC 7222 11F6 5947 1415 B654
>
>------------------------ MailScanner list ------------------------
>To unsubscribe, email jiscmail at jiscmail.ac.uk with the words:
>'leave mailscanner' in the body of the email.
>Before posting, read the MAQ (http://www.mailscanner.biz/maq/) and
>the archives (http://www.jiscmail.ac.uk/lists/mailscanner.html).
>
>Support MailScanner development - buy the book off the website!
>
>

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