From:
Operating system: ALL
PHP version: 5.3.2
Package: *Compression related
Bug Type: Bug
Bug description:base64_decode() improper handling of leading padding.
Description:
------------
According to the MIME standard that we're following, this isn't supposed to
work when strict mode is enabled. Equal-signs are strictly reserved for
padding characters at the _end_ of a base64 MIME string.
Leading '=' signs are allowed in each block of 4 bytes because the
condition that checks for invalid placement of the '=' signs only checks if
(i % 4) == 1,
Whereas it should check if (i % 4) is 0 or 1.
You should be able to change the circumstances for a valid '=' placement,
as follows, to conform to the standard:
// to see if bit position 2 is set (for all values of i = n*4+2 and i =
n*4+3)
if (i & 2)
// means that the '=' is in a valid location
I would also suggest *carefully* looking over the block at the end of the
base64_decode() function... as it seems that if (ch == base64_pad) after ch
is ALWAYS set to '\0' is an impossible scenario.
Test script:
---------------
<?php
echo
base64_decode('=VGhl=ICc9=JyBz=eW1i=b2xz=IGFy=ZW4n=dCBh=bGxv=d2Vk=IHdo=ZXJl=IGkg=cHV0=IHRo=ZW0g=by5P');
?>
Expected result:
----------------
should return FALSE/NULL/Errornous value
Actual result:
--------------
echos:
The '=' symbols aren't allowed where i put them o.O
--
Edit bug report at http://bugs.php.net/bug.php?id=52327&edit=1
--
Try a snapshot (PHP 5.2):
http://bugs.php.net/fix.php?id=52327&r=trysnapshot52
Try a snapshot (PHP 5.3):
http://bugs.php.net/fix.php?id=52327&r=trysnapshot53
Try a snapshot (trunk):
http://bugs.php.net/fix.php?id=52327&r=trysnapshottrunk
Fixed in SVN:
http://bugs.php.net/fix.php?id=52327&r=fixed
Fixed in SVN and need be documented:
http://bugs.php.net/fix.php?id=52327&r=needdocs
Fixed in release:
http://bugs.php.net/fix.php?id=52327&r=alreadyfixed
Need backtrace:
http://bugs.php.net/fix.php?id=52327&r=needtrace
Need Reproduce Script:
http://bugs.php.net/fix.php?id=52327&r=needscript
Try newer version:
http://bugs.php.net/fix.php?id=52327&r=oldversion
Not developer issue:
http://bugs.php.net/fix.php?id=52327&r=support
Expected behavior:
http://bugs.php.net/fix.php?id=52327&r=notwrong
Not enough info:
http://bugs.php.net/fix.php?id=52327&r=notenoughinfo
Submitted twice:
http://bugs.php.net/fix.php?id=52327&r=submittedtwice
register_globals:
http://bugs.php.net/fix.php?id=52327&r=globals
PHP 4 support discontinued: http://bugs.php.net/fix.php?id=52327&r=php4
Daylight Savings: http://bugs.php.net/fix.php?id=52327&r=dst
IIS Stability:
http://bugs.php.net/fix.php?id=52327&r=isapi
Install GNU Sed:
http://bugs.php.net/fix.php?id=52327&r=gnused
Floating point limitations:
http://bugs.php.net/fix.php?id=52327&r=float
No Zend Extensions:
http://bugs.php.net/fix.php?id=52327&r=nozend
MySQL Configuration Error:
http://bugs.php.net/fix.php?id=52327&r=mysqlcfg
