Description:
------------
The COPY function can write/read files where you have no permission to. (Maybe in combination with the tempnam function, maybe without).

Reproduce code:
---------------
$tempfn = tempnam("","");
$temp = fopen($tempfn, "w");
fwrite ($temp, $newtxt);
copy ($tempfn, "mysql.php");


Expected result:
----------------
Line 1:
$tempfn = the created temporary filename.
Line 2:
Open the temp. file with write access.
Line 3:
write your text $newtxt in $temp.
Line 4:
Copy your newly created temporary file over mysql.php, even without write access.

Actual result:
--------------
(same as above)

Line 1:
$tempfn = the created temporary filename.
Line 2:
Open the temp. file with write access.
Line 3:
write your text $newtxt in $temp.
Line 4:
Copy your newly created temporary file over mysql.php, even without write access.