From: phil at preterition dot net
Operating system: Mac OS X or Linux
PHP version: 4.3.3RC3
PHP Bug Type: Reproducible crash
Bug description: Recursive constructor segfaults php
Description:
------------
Script recursively calls class b()'s constructor. Due to the use of
alloca for execution of the constructor, the process Dies Horribly rather
than issuing a valid error code (which would normally facilitate at least
an error message.) when it runs out of stack.
Reproduce code:
---------------
<?php
class a {
var $y;
}
class b extends a {
function b() {
$this->{get_parent_class($this)}();
}
}
class c extends b {
function c() {
$this->{get_parent_class($this)}();
}
}
$f = new c();
?>
Expected result:
----------------
I'd like to see the zend engine throw an error when it runs out of stack,
but I don't see how (without moving off of alloca and taking a performance
hit) it can be implemented.
I don't believe this is a security issue due to libc killing the process
rather than returning an error which zend_execute.c doesn't catch.
I've worked around the code in question by rearchitecting my class
hierarchy. Looking forward to multiple inheritance in PHP5?
Actual result:
--------------
Backtrace Follows:
Program received signal EXC_BAD_ACCESS, Could not access memory.
0x00172a94 in _zend_is_inconsistent (ht=0x180638, file=0x0, line=0) at
/Users/porwig/Development/php-4.3.3RC3/Zend/zend_hash.c:83
83 {
(gdb) bt
#0 0x00172a94 in _zend_is_inconsistent (ht=0x180638, file=0x0, line=0) at
/Users/porwig/Development/php-4.3.3RC3/Zend/zend_hash.c:83
#1 0x00180638 in zend_fetch_var_address (opline=0x4e8868, Ts=0xbff80140,
type=0) at /Users/porwig/Development/php-4.3.3RC3/Zend/zend_execute.c:581
#2 0x00182ea4 in execute (op_array=0x4e9fb8) at
/Users/porwig/Development/php-4.3.3RC3/Zend/zend_execute.c:1248
#3 0x001853f0 in execute (op_array=0x4e9fb8) at
/Users/porwig/Development/php-4.3.3RC3/Zend/zend_execute.c:1660
#4 0x001853f0 in execute (op_array=0x4e9fb8) at
/Users/porwig/Development/php-4.3.3RC3/Zend/zend_execute.c:1660
... snip ...
#748 0x001853f0 in execute (op_array=0x4e9fb8) at
/Users/porwig/Development/php-4.3.3RC3/Zend/zend_execute.c:1660
#749 0x001853f0 in execute (op_array=0x4eb488) at
/Users/porwig/Development/php-4.3.3RC3/Zend/zend_execute.c:1660
#750 0x001853f0 in execute (op_array=0x4e6cf8) at
/Users/porwig/Development/php-4.3.3RC3/Zend/zend_execute.c:1660
#751 0x0016c8d4 in zend_execute_scripts (type=8, retval=0x0, file_count=3)
at /Users/porwig/Development/php-4.3.3RC3/Zend/zend.c:885
#752 0x0011f298 in php_execute_script (primary_file=0xbffff740) at
/Users/porwig/Development/php-4.3.3RC3/main/main.c:1720
#753 0x0018cb64 in main (argc=2, argv=0xbffffc90) at
/Users/porwig/Development/php-4.3.3RC3/sapi/cli/php_cli.c:818
#754 0x00001e44 in _start (argc=2, argv=0xbffffc90, envp=0xbffffc9c) at
/SourceCache/Csu/Csu-45/crt.c:267
#755 0x00001cc4 in start ()
(gdb)
--
Edit bug report at http://bugs.php.net/?id=25002&edit=1
--
Try a CVS snapshot (php4): http://bugs.php.net/fix.php?id=25002&r=trysnapshot4
Try a CVS snapshot (php5): http://bugs.php.net/fix.php?id=25002&r=trysnapshot5
Fixed in CVS: http://bugs.php.net/fix.php?id=25002&r=fixedcvs
Fixed in release: http://bugs.php.net/fix.php?id=25002&r=alreadyfixed
Need backtrace: http://bugs.php.net/fix.php?id=25002&r=needtrace
Try newer version: http://bugs.php.net/fix.php?id=25002&r=oldversion
Not developer issue: http://bugs.php.net/fix.php?id=25002&r=support
Expected behavior: http://bugs.php.net/fix.php?id=25002&r=notwrong
Not enough info: http://bugs.php.net/fix.php?id=25002&r=notenoughinfo
Submitted twice: http://bugs.php.net/fix.php?id=25002&r=submittedtwice
register_globals: http://bugs.php.net/fix.php?id=25002&r=globals
PHP 3 support discontinued: http://bugs.php.net/fix.php?id=25002&r=php3
Daylight Savings: http://bugs.php.net/fix.php?id=25002&r=dst
IIS Stability: http://bugs.php.net/fix.php?id=25002&r=isapi
Install GNU Sed: http://bugs.php.net/fix.php?id=25002&r=gnused
