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bug, regex error or clever email sender address?

Printed From: LogSat Software
Category: Spam Filter ISP
Forum Name: Spam Filter ISP Support
Forum Description: General support for Spam Filter ISP
URL: https://www.logsat.com/spamfilter/forums/forum_posts.asp?TID=3370
Printed Date: 23 July 2025 at 2:21am


Topic: bug, regex error or clever email sender address?
Posted By: Guests
Subject: bug, regex error or clever email sender address?
Date Posted: 02 April 2004 at 4:28am

04.02.04 11:21:33:361 -- (2484) String matching error for ( mailto:emailSenderApp+1IPIM4U31S4W3-2T3J2GDFUIM5L-25CJOYEOL8CT5@bounces.amazon.com" CLASS="ASPForums" TITLE="WARNING: URL created by poster. - emailSenderApp+1IPIM4U31S4W3-2T3J2GDFUIM5L-25CJOYEOL8CT5@bounces.amazon.com --and-- ([d+]([-a-za-z0-9_.+])+(@hotmail|@juno|@yahoo).com)) : TRegExpr(exec): Loop Stack Exceeded

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This is a copy from the activity log as I saw some messages passing the filter by

giving spamfilter a stack error...

Can anyone see what went wrong with this one?

(using version 2.0.1.315 registered)


Replies:
Posted By: Desperado
Date Posted: 02 April 2004 at 3:40pm

Actually,  This is my RegEx and nothing "oficially" went wrong.  The address is so long that the SpamFilter RegEx Parser reached a hard coded limit and the error you get is as you see.  This is a non critical error that Roberto can explain MUCH better than I can but it does not cause any issues.  The SpamFilter just goes on to the next filter from there.

This RegEx, in my system, catches a bunch and barfs on a bunch like you have seen but it still does reduce the spam so I have learned to ignore those errors.

Dan S.

 

Posted By: Desperado
Date Posted: 02 April 2004 at 3:44pm

Oh!  And I stand corrected ... this is a little changed from the RegEx I uses but the answer is still the same.  Mine is as folloes:

(\b[\d+]+([\-a-za-z0-9_\.\+])+(@hotmail|@juno)\.com)

VERY similar so I think the Loop Stack issue applies to yours also.

Regards

Dan S.

Posted By: LogSat
Date Posted: 04 April 2004 at 12:36am

Ronny T,

Dan is absolutely correct in his statement. Some RegEx expressions require a string to be parsed several times with recursive loops in order to match all searches. If the "recursivity" functions are very "deep", meaning a recursive function calls itself, which then calls itself, and calls itself again, and again etc, this could cause some Windows stack overflows and bring the server to its knees (especially if several incoming emails are processed concurrently). In order to avoid this, we've placed a hardcoded limit in how many levels deep a recursive function can go. When the limit is reached a "soft error" breaks the loop and halts the search for that particular string. This is totally harmless, and will not cause any other errors, but will usually cause the particular searh string to be ignored.

Roberto F.
LogSat Software


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