Description:
------------
Downloaded PHP 5.3.3 from: http://windows.php.net/downloads/releases/archives/php-5.3.3-nts-Win32-VC9-x86.zip
Downloaded PHP 5.3.4 from: http://windows.php.net/downloads/releases/php-5.3.4-nts-Win32-VC9-x86.zip

The following settings has the expected results in both PHP 5.3.3 and PHP 5.3.4
open_basedir="C:\twlan\"
open_basedir="C:\twlan"
open_basedir="C:/twlan"
open_basedir="C:/twlan\"

The following setting breaks open_basedir in PHP 5.3.4, but works fine in 5.3.3.
open_basedir="C:/twlan/"

So, the trailing forward slash on open_basedir makes every path invalid.

Changes between 5.3.3 and 5.3.4:
http://svn.php.net/viewvc/php/php-src/branches/PHP_5_3/main/fopen_wrappers.c?r1=301440&r2=306091

I think the bug was introduced in http://svn.php.net/viewvc/php/php-src/trunk/main/fopen_wrappers.c?r1=305098&r2=305698
--- begin code ---
@@ -228,6 +234,9 @@
 				resolved_basedir[resolved_basedir_len] = PHP_DIR_SEPARATOR;
 				resolved_basedir[++resolved_basedir_len] = '\0';
 			}
+		} else {
+				resolved_basedir[resolved_basedir_len++] = PHP_DIR_SEPARATOR;
+				resolved_basedir[resolved_basedir_len] = '\0';
 		}
 
 		resolved_name_len = strlen(resolved_name);
--- end code ---
PHP_DIR_SEPARATOR is "\\" on Windows.

Test script:
---------------
<?php
// open_basedir="C:/twlan/"
header("Content-Type: text/plain");
error_reporting(E_ALL | E_STRICT);
ini_set('html_errors', 0);
var_dump(realpath('.'));
var_dump(realpath('..'));
var_dump(realpath('../..'));
var_dump(realpath('../../..'));
?>

Expected result:
----------------
string(22) "C:\twlan\htdocs\combot"
string(15) "C:\twlan\htdocs"
string(8) "C:\twlan"

Warning: realpath(): open_basedir restriction in effect. File(C:\) is not within the allowed path(s): (C:/twlan/) in C:\twlan\htdocs\combot\php-bug.php on line 7
bool(false)


Actual result:
--------------
Warning: realpath(): open_basedir restriction in effect. File(C:\twlan\htdocs) is not within the allowed path(s): (C:/twlan/) in C:\twlan\htdocs\combot\php-bug.php on line 5
bool(false)

Warning: realpath(): open_basedir restriction in effect. File(C:\twlan\htdocs) is not within the allowed path(s): (C:/twlan/) in C:\twlan\htdocs\combot\php-bug.php on line 5
bool(false)

Warning: realpath(): open_basedir restriction in effect. File(C:\twlan) is not within the allowed path(s): (C:/twlan/) in C:\twlan\htdocs\combot\php-bug.php on line 6
bool(false)

Warning: realpath(): open_basedir restriction in effect. File(C:\) is not within the allowed path(s): (C:/twlan/) in C:\twlan\htdocs\combot\php-bug.php on line 7
bool(false)