From:             ibexris at gmail dot com
Operating system: FC5
PHP version:      5.1.4
PHP Bug Type:     Reproducible crash
Bug description:  preg_match segfaults with large negative lookaheads (pcre bug)

Description:
------------
This is a rehash/update of Bug #27525
(http://bugs.php.net/bug.php?id=27525), which I can't update (you guys
really need a way for new people to add comments to existing tickets).

Not sure if the original submitter ever emailed Philip, but after bumping
my head against this problem yesterday, I contacted him myself.

He is now able to reproduce the bug in the current version of pcre (6.7),
and expects to have a fix sometime in september or october (the first
chance he'll have to actually look at the code).  I've created this new
ticket because there will be a pending fix upstream.

fyi, better code to reproduce:

<?php
  $string = str_repeat('x', 11000);
  $pattern = '/(.(?!b))*/';
  echo preg_match($pattern, $string);
?>

And a workaround, since none was posted before:

<?php
  $pattern = '/(.(?!b)){0,540}/';
?>

You can't go above 540 because preg_replace complains about the pattern
being too large.


-- 
Edit bug report at http://bugs.php.net/?id=38401&edit=1
-- 
Try a CVS snapshot (PHP 4.4): 
http://bugs.php.net/fix.php?id=38401&r=trysnapshot44
Try a CVS snapshot (PHP 5.2): 
http://bugs.php.net/fix.php?id=38401&r=trysnapshot52
Try a CVS snapshot (PHP 6.0): 
http://bugs.php.net/fix.php?id=38401&r=trysnapshot60
Fixed in CVS:                 http://bugs.php.net/fix.php?id=38401&r=fixedcvs
Fixed in release:             
http://bugs.php.net/fix.php?id=38401&r=alreadyfixed
Need backtrace:               http://bugs.php.net/fix.php?id=38401&r=needtrace
Need Reproduce Script:        http://bugs.php.net/fix.php?id=38401&r=needscript
Try newer version:            http://bugs.php.net/fix.php?id=38401&r=oldversion
Not developer issue:          http://bugs.php.net/fix.php?id=38401&r=support
Expected behavior:            http://bugs.php.net/fix.php?id=38401&r=notwrong
Not enough info:              
http://bugs.php.net/fix.php?id=38401&r=notenoughinfo
Submitted twice:              
http://bugs.php.net/fix.php?id=38401&r=submittedtwice
register_globals:             http://bugs.php.net/fix.php?id=38401&r=globals
PHP 3 support discontinued:   http://bugs.php.net/fix.php?id=38401&r=php3
Daylight Savings:             http://bugs.php.net/fix.php?id=38401&r=dst
IIS Stability:                http://bugs.php.net/fix.php?id=38401&r=isapi
Install GNU Sed:              http://bugs.php.net/fix.php?id=38401&r=gnused
Floating point limitations:   http://bugs.php.net/fix.php?id=38401&r=float
No Zend Extensions:           http://bugs.php.net/fix.php?id=38401&r=nozend
MySQL Configuration Error:    http://bugs.php.net/fix.php?id=38401&r=mysqlcfg

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