#48501 [Opn->Csd]: Crash with preg_replace_callback
ID: 48501
Updated by: scottmac@php.net
Reported By: cobexer at gmail dot com
-Status: Open
+Status: Closed
Bug Type: PCRE related
Operating System: Linux/openSuSE 11.1
PHP Version: 5.2.9
New Comment:
This was only fixed in 5.3, I've now backported it to 5.2.
Previous Comments:
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[2009-06-08 21:38:04] cobexer at gmail dot com
after submitting I found a similar bug ... #44214
but that one is closed and seems to be "fixed" since one year now...
------------------------------------------------------------------------
[2009-06-08 21:33:44] cobexer at gmail dot com
Description:
------------
when i tried to match nested patterns my apache2 with php crashed -
however for similar inputs a very similar regular expression is in use
and causes no problems... (but the crash seems to be related to the
number of nesting levels)
Reproduce code:
---------------
<?php
//long test string -> crash
$match=
"{IF(a)}if{IF(a)}fi{IF(a)}if{ELSE}else{/IF}{ELSE}else{IF(a)}if{ELSE}else{/IF}{/IF}{ELSE}else{IF(a)}if{ELSE}else{IF(a)}if{ELSE}else{/IF}{/IF}{/IF}";
//shorter test string -> still crash, but if 1 remove the first nested
{IF... it doesnt crash any more
$match=
"{IF(a)}if{IF(a)}fi{ELSE}else{/IF}{ELSE}else{IF(a)}if{ELSE}else{/IF}{/IF}";
$reg= '/\{IF\((.*)\)\}([^\{]+?)(\{ELSE\})?([^\{]*?)(\{\/IF\})/Us';
$matches= array();
function cback($t) { global $matches; $matches[]= $t; return '';}
preg_replace_callback($reg, 'cback', $match);
var_dump($matches);
?>
Expected result:
----------------
array with the mathes of the regExp correctly nested... but i was in
the stage of designing the regular expression itself - at least i did
not expect a crash...
Actual result:
--------------
Apache/2.2.10 (php loaded as module) error_log:
without 3rd party extensions:
[notice] child pid 11335 exit signal Segmentation fault (11)
with XDebug enabled:
[error] [client 127.0.0.1] ALERT - possible memory corruption detected
- unknown Hashtable destructor (attacker '127.0.0.1', file
'/path/file.php')
when running php from the command line (no crash -> no backtrace):
$ php reproduce.php #same content as the code posted above!
array(2) {
[0]=>
*RECURSION*
[1]=>
*RECURSION*
}
ALERT - possible memory corruption detected - unknown Hashtable
destructor (attacker 'REMOTE_ADDR not set', file 'unknown')
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