ID: 14425
User updated by: philhassey@hotmail.com
Reported By: philhassey@hotmail.com
Status: Open
Bug Type: Variables related
Operating System: Linux (Mandrake 8.1)
PHP Version: 4.0.6
New Comment:
Similarily, this bug is also found in class methods.
class a
{
function test()
{
$a=array("this"=>"nothing","GLOBALS"=>"nothing");
extract($a);
var_dump($this);
var_dump($GLOBALS);
}
}
$a=new a();
$a->test();
// Both this and GLOBALS are overwritten by extract.
// I would have hoped that would not have happened.
Previous Comments:
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[2001-12-11 08:55:15] philhassey@hotmail.com
//I did this:
function test()
{
$a=array("GLOBALS"=>"nothing");
extract($a);
var_dump($GLOBALS);
}
test();
// The script will overwrite the $GLOBALS variable
// I did not want it to overwrite the $GLOBALS variable
// Then in the global scope, I did this:$a=array("GLOBALS"=>"nothing");
extract($a);
var_dump($GLOBALS);
//The script did not overwrite the $GLOBALS variable.
// It did what I wanted it to do.
By allowing the extract function to overwrite global variables within a function can lead to serious
security holes. Particularily if URL parameters are passed into a function that extracts them.
(And then if my function still expects GLOBALS to be legit, it could be passed false information.)
I suggest making extract unable to overwrite any global variables within a function. ($GLOBALS, and
any variables declared global $x, etc..) As a second measure it might be good to make extract more
conservative in general by defaulting to EXTR_SKIP instead of EXTR_OVERWRITE
I can, of course, fix my own code for the time being to avoid this problem by using
extract($params,EXTR_SKIP); However I think fixing the problem for PHP as a whole would help others
as well.
Thank you. Keep up the excellent work!
Phil
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Edit this bug report at http://bugs.php.net/?id=14425&edit=1