PHP :: Bug #27460 :: base64_decode fails to follow RFC 3548 completely

 [2004-03-02 09:43 UTC] naish at klanen dot net

Description:
------------
If a base64 encoded string contains a non-needed "=" at the end of the string base64_decode returns false even though the string has been correctly decoded.
The standard for base64 even specifies that a file may contain non-needed padding chars.
http://www.faqs.org/rfcs/rfc3548.html
- snip -
Furthermore, such specifications may consider the pad character, "=", as not part of the base alphabet until the end of the string.  If more than the allowed number of pad characters are found at the end of the string, e.g., a base 64 string terminated with "===", the excess pad characters could be ignored.
- /snip -
The fix is simple. In ext/standard/base64.c insert the following code:
        if (ch == base64_pad) {
                switch(i % 4) {
                case 1:
                        efree(result);
                        return NULL;
                case 2:
                        k++;
                case 3:
                        result[k++] = 0;
                }
        }
in the base64_decode function. Notice that the only thing I did was remove "case 0:" on line 191.
Reproduce code:
---------------
<?php
	$string=base64_encode("123456");
	echo $string."\n";
	//Insert a not-needed padding char.
	$string.="=";
	//This returns false even though $string is valid base64
	var_dump(base64_decode($string));
?>
Expected result:
----------------
$string should been encoded to base64 and later decoded with 1 extra "=" added at the end.
Actual result:
--------------
PHP fails to decode the string properly.

 [2004-03-06 13:58 UTC] iliaa@php.net

This bug has been fixed in CVS.
Snapshots of the sources are packaged every three hours; this change
will be in the next snapshot. You can grab the snapshot at
http://snaps.php.net/.
Thank you for the report, and for helping us make PHP better.