Description:
------------
When register_globals is on, and after a session has already been started, $_SESSION values can be changed indirectly.

$_SESSION['userID'] = 'carl';
$userID = $_SESSION['userID'];
$userID = 'HAXOR';
# now $_SESSION['userID'] is 'HAXOR'

To me, this seems like a bad thing.

Happens under Mac OS 10.2, w/ PHP 4.3.2
Happens under Win2K w/ PHP 4.3.2
Doesn't happen under Linux w/ PHP 4.2.3


Reproduce code:
---------------
<?
# Demonstrates that $_SESSION can be changed indirectly.
# the alleged bug activates when register_globals is ON.

# set a userID in the session
session_start();
$_SESSION['userID'] = 'carl';
  
# copy userID into a global variable, $userID
$userID = $_SESSION['userID'];
  
# change only $userID
print "before: ". $_SESSION['userID'] ."<br>\n";
$userID = 'HAXOR';
print "after: ". $_SESSION['userID'] ."<br>\n";
if ( $_SESSION['userID']=='HAXOR' ) { print "bad"; }
  
# seems very wrong that $_SESSION['userID'] was changed
?>

Expected result:
----------------
After I run the script and reload it once, I should not see "bad" because changing $userID should not change $_SESSION['userID'].


Actual result:
--------------
bad