Bug #51777 [NEW]: RegEx matching fails

From: Date: Sun, 09 May 2010 16:37:00 +0000
Subject: Bug #51777 [NEW]: RegEx matching fails
Groups: php.bugs 
Request: Send a blank email to php-bugs+get-150283@lists.php.net to get a copy of this message 
From:             
Operating system: Windows XP and Linux Server
PHP version:      5.3.2
Package:          Regexps related
Bug Type:         Bug
Bug description:RegEx matching fails

Description:
------------
When a RegEx "looks" over ~32768 times during a successful match, every
RegEx function fails and returns the empty string.



Test script:
---------------
<?php

	$response = http_get("http://www.travelocity.com");
	// no problem with these first 2 RegExs
	$response2 = preg_replace('/\s+/'," ",$response);
	$mytitle =
preg_replace('/.*?<\s*title\s*>([^<]*)<.*/i','${1}',$response2);
	echo "\nTitle Match Forward: ".$mytitle."\n\n";
	// now, here's a problem
	$mytitle2 =
preg_replace('/.*<\s*title\s*>([^<]*)<.*/i','${1}',$response2);
	echo "\nTitle Match Backward: ".$mytitle2."\n\n";

?>

Expected result:
----------------
$mytitle gets extracted properly and echoed because the RegEx never looks
more than 32768 times starting at the beginning of the travelocity.com page
source.  $mytitle2 never gets extracted because the RegEx looks more than
32768 times successfully and preg_replace() crashes into the empty string. 
Matching forward for the title is working; matching backward for the title
is failing for large buffers.

Actual result:
--------------
Title Match Forward: Travelocity Travel: Airline Tickets, Hotels, Flights,
Vacations, Cruises &amp; Car Rentals


Title Match Backward: 

-- 
Edit bug report at http://bugs.php.net/bug.php?id=51777&edit=1
-- 
Try a snapshot (PHP 5.2):            http://bugs.php.net/fix.php?id=51777&r=trysnapshot52
Try a snapshot (PHP 5.3):            http://bugs.php.net/fix.php?id=51777&r=trysnapshot53
Try a snapshot (PHP 6.0):            http://bugs.php.net/fix.php?id=51777&r=trysnapshot60
Fixed in SVN:                        http://bugs.php.net/fix.php?id=51777&r=fixed
Fixed in SVN and need be documented: http://bugs.php.net/fix.php?id=51777&r=needdocs
Fixed in release:                    http://bugs.php.net/fix.php?id=51777&r=alreadyfixed
Need backtrace:                      http://bugs.php.net/fix.php?id=51777&r=needtrace
Need Reproduce Script:               http://bugs.php.net/fix.php?id=51777&r=needscript
Try newer version:                   http://bugs.php.net/fix.php?id=51777&r=oldversion
Not developer issue:                 http://bugs.php.net/fix.php?id=51777&r=support
Expected behavior:                   http://bugs.php.net/fix.php?id=51777&r=notwrong
Not enough info:                     http://bugs.php.net/fix.php?id=51777&r=notenoughinfo
Submitted twice:                     http://bugs.php.net/fix.php?id=51777&r=submittedtwice
register_globals:                    http://bugs.php.net/fix.php?id=51777&r=globals
PHP 4 support discontinued:          http://bugs.php.net/fix.php?id=51777&r=php4
Daylight Savings:                    http://bugs.php.net/fix.php?id=51777&r=dst
IIS Stability:                       http://bugs.php.net/fix.php?id=51777&r=isapi
Install GNU Sed:                     http://bugs.php.net/fix.php?id=51777&r=gnused
Floating point limitations:          http://bugs.php.net/fix.php?id=51777&r=float
No Zend Extensions:                  http://bugs.php.net/fix.php?id=51777&r=nozend
MySQL Configuration Error:           http://bugs.php.net/fix.php?id=51777&r=mysqlcfg

Thread (7 messages)

« previous php.bugs (#150283) next »