Edit report at https://bugs.php.net/bug.php?id=63882&edit=1

 ID:                 63882
 Updated by:         a...@php.net
 Reported by:        gynvael at coldwind dot pl
 Summary:            zend_std_compare_objects crash on recursion
-Status:             Open
+Status:             Analyzed
 Type:               Bug
 Package:            Reproducible crash
 Operating System:   any
 PHP Version:        5.4.10
 Block user comment: N
 Private report:     N



Previous Comments:
------------------------------------------------------------------------
[2013-01-02 19:03:05] a...@php.net

The stack overflow happens only with default class properties. Non default 
object properties are stored in the HashTable and it's protected against 
recursion.

The solution I'm suggesting in the patch is simple but could be binary 
incompatible to the stuff in the outer world. I mean the stuff like pre 
compiled pecl extensions, as the zend_object size changes. May be that should 
only go into 5.5

Another solution were quite complex - compare_function could be extended with a 
recursion count argument, but that would need a lot of places to be touched.

------------------------------------------------------------------------
[2013-01-02 18:53:25] a...@php.net

The following patch has been added/updated:

Patch Name: 63882.patch
Revision:   1357152805
URL:        
https://bugs.php.net/patch-display.php?bug=63882&patch=63882.patch&revision=1357152805

------------------------------------------------------------------------
[2013-01-01 19:27:30] gynvael at coldwind dot pl

Description:
------------
The standard PHP object compare handler (zend_std_compare_objects) together 
with 
the == operator (compare_function) have no limit on nesting levels nor any anti-
recursion protection.

The array comparing function in compare_function does have this protection. It 
would be good to add it to the object standard compare handler as well.

Test script:
---------------
<?php
class Test { public $x = 5; }

$testobj1 = new Test;
$testobj2 = new Test;
$testobj1->x = $testobj1;
$testobj2->x = $testobj2;

$testobj1 == $testobj2; // Crash (stack exhaustion)


Expected result:
----------------
PHP Fatal error:  Nesting level too deep - recursive dependency? in test.php on 
line 9

Actual result:
--------------
segmentation fault (core dumped)


------------------------------------------------------------------------



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