Bug #17799 Updated: Using $this->$variable_name inside object clears all variable values
| From: | mfischer@php.net | Date: | Mon, 17 Jun 2002 16:28:34 +0000 |
| Subject: | Bug #17799 Updated: Using $this->$variable_name inside object clears all variable values | ||
| References: | 1 | Groups: | php.bugs |
| Request: | Send a blank email to php-bugs+get-10880@lists.php.net to get a copy of this message | ||
ID: 17799
Updated by: mfischer@php.net
Reported By: qdot@numberporn.com
-Status: Feedback
+Status: Open
Bug Type: Class/Object related
-Operating System: Win XP Pro- Should be indep.
+Operating System: Any
-PHP Version: 4.2.1
+PHP Version: CVS
New Comment:
Shorter example:
<?
class foo {
var $a;
var $b;
function foo() {
$this->$notdefined = 0;
}
function getA() {
return "a='" . $this->$a . "'";
}
function getB() {
return "b='" . $this->$b . "'";
}
function setA($a_ = "") {
$this->$dontexistseither = $a_;
}
}
$o = new foo();
echo $o->getA() . "\n";
echo $o->getB() . "\n";
$o->setA(500);
echo $o->getA() . "\n";
echo $o->getB() . "\n";
?>
Outputs: $ php bug_17799.php
a='0'
b='0'
a='500'
b='500'
Previous Comments:
------------------------------------------------------------------------
[2002-06-17 10:29:29] sander@php.net
Does my simple testscript give the same problem? Your test script is
too long to serve as a test script, you'll lose track of it at once.
Please track the problem down to only a couple of lines.
------------------------------------------------------------------------
[2002-06-17 10:05:45] qdot@numberporn.com
Here's the exact script we used when we found this bug:
----
TableProperties.class
<?
/***********************************************
* This class represents the attributes which define
* the properties of a Table.
*/
class TableProperties
{
//the attributes which define a table
var $widthTable;
var $heightTable;
var $cellPadding;
var $cellSpacing;
var $border;
var $widthCell;
var $heightCell;
var $hAlignCell;
var $vAlignCell;
/**
* Constructor of the class. Main purpose is to
* initialize the variables with a value as a default.
*/
function TableProperties()
{
$this->$widthTable = "";
$this->$heightTable = "";
$this->$cellPadding = 0;
$this->$cellSpacing = 0;
$this->$border = 0;
$this->$widthCell = "";
$this->$heightCell = "";
$this->$hAlignCell = "center";
$this->$vAlignCell = "top";
}
/**
* Returns the attributes as a key-value pair
* that is compatible with HTML.
*/
function getWidthTablePair() { return ("width='" . $this->$widthTable
. "'"); }
function getHeightTablePair() { return ("height='" .
$this->$heightTable . "'"); }
function getCellPaddingPair() { return ("cellpadding='" .
$this->$cellPadding . "'"); }
function getCellSpacingPair() { return ("cellspacing='" .
$this->$cellSpacing . "'"); }
function getBorderPair() { return ("border='" . $this->$border .
"'");
}
function getWidthCellPair() { return ("width='" . $this->$widthCell .
"'"); }
function getHeightCellPair() { return ("height='" . $this->$heightCell
. "'"); }
function getHAlignCellPair() { return ("align='" . $this->$hAlignCell
. "'"); }
function getVAlignCellPair() { return ("valign='" . $this->$vAlignCell
. "'"); }
/**
* Returns the values of the attributes.
*/
function getWidthTable() { return $this->$widthTable; }
function getHeightTable() { return $this->$heightTable; }
function getCellPadding() { return $this->$cellPadding; }
function getCellSpacing() { return $this->$cellSpacing; }
function getBorder() { return $this->$border; }
function getWidthCell() { return $this->$widthCell; }
function getHeightCell() { return $this->$heightCell; }
function getHAlignCell() { return $this->$hAlignCell; }
function getVAlignCell() { return $this->$vAlignCell; }
/**
* Sets the variables to the given value.
*/
function setWidthTable($widthTable_ = "") { $this->$widthTable =
$widthTable_; }
function setHeightTable($heightTable_ = "") { $this->$heightTable =
$heightTable_; }
function setCellPadding($cellPadding_ = "") { $this->$cellPadding =
$cellPadding_; }
function setCellSpacing($cellSpacing_ = "") { $this->$cellSpacing =
$cellSpacing_; }
function setBorder($border_ = "") { $this->$border = $border_; }
function setWidthCell($widthCell_ = "") { $this->$widthCell =
$widthCell_; }
function setHeightCell($heightCell_ = "") { $this->$heightCell =
$heightCell_; }
function setHAlignCell($hAlignCell_ = "") { $this->$hAlignCell =
$hAlignCell_; }
function setVAlignCell($vAlignCell_ = "") { $this->$vAlignCell =
$vAlignCell_; }
}
?>
----
test-00.php
<?php
require("TableProperties.class");
$tp = new TableProperties();
echo $tp->getHeightTablePair() . "<br>";
echo $tp->getWidthTablePair() . "<br>";
echo $tp->getBorderPair() . "<br>";
echo $tp->getVAlignCellPair() . "<br>";
$tp->setHeightTable(500);
$tp->setWidthTable("600");
$tp->setBorder(5);
//$tp->setVAlignCell("bottom");
echo $tp->getHeightTablePair() . "<br>";
echo $tp->getWidthTablePair() . "<br>";
echo $tp->getBorderPair() . "<br>";
echo $tp->getVAlignCellPair() . "<br>";
?>
----
Output is:
>php test-00.php
X-Powered-By: PHP/4.2.1
Content-type: text/html
height='top'<br>width='top'<br>border='top'<br>valign='top'<br>height='5'<br>width='5'<br>border='5'<br>valign='5'<br>
------------------------------------------------------------------------
[2002-06-17 09:58:20] sander@php.net
Can't reproduce:
$ php -v
PHP 4.3.0-dev (cli), Copyright (c) 1997-2002 The PHP Group
Zend Engine v1.2.1, Copyright (c) 1998-2002 Zend Technologies
$ cat test.php
<?php
error_reporting(E_ALL);
class foo {
var $a = 'a';
var $b = 'b';
function foo() {
$this->$a = 'foo';
}
}
$foo = &new foo();
print_r($foo);
?>
$ php test.php
Notice: Undefined variable: a in test.php on line 8
foo Object
(
[a] => a
[b] => b
[] => foo
)
Can you provide a simple and selfcontained sample script that
reproduces the problem?
------------------------------------------------------------------------
[2002-06-17 08:40:34] qdot@numberporn.com
Summary: When accidently using the syntax $this->$variable_name in an
object to set a variable, all the variables in the object are set to
the value that is given. This seems like it could cause a serious
security issue.
Steps to reproduce:
1. Create an object with multiple class variables
2. Create an setVar function with the incorrect syntax
3. Instantiate a new variable in a script to the class and use the
setVar function. All variables in the object will now hold this value.
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=17799&edit=1