From:             hello at iwamot dot com
Operating system: all
PHP version:      5.3.0
PHP Bug Type:     Strings related
Bug description:  htmlspecialchars() should check byte sequence more strictly

Description:
------------
Suppose htmlspecialchars() should check byte sequence more strictly for
security reasons. An XSS exploit code has been unveiled.
http://d.hatena.ne.jp/t_komura/20091004/1254665511 [ja]

I wrote a primitive patch.
http://iwamot.com/misc/html.c.patch.20091006
I don't know whether it is useful though :)

Reproduce code:
---------------
// overlong UTF-8 sequence
echo htmlspecialchars("A\xC0\xAF&",     ENT_QUOTES, 'UTF-8');
// invalid Shift_JIS sequence
echo htmlspecialchars("B\x80&",         ENT_QUOTES, 'Shift_JIS');
echo htmlspecialchars("C\x81\x7f&",     ENT_QUOTES, 'Shift_JIS');
// invalid EUC-JP sequence
echo htmlspecialchars("D\x80&",         ENT_QUOTES, 'EUC-JP');
echo htmlspecialchars("E\xA1\xFF&",     ENT_QUOTES, 'EUC-JP');
echo htmlspecialchars("F\x8E\xFF&",     ENT_QUOTES, 'EUC-JP');
echo htmlspecialchars("G\x8F\xA1\xFF&", ENT_QUOTES, 'EUC-JP');

Expected result:
----------------
output nothing

Actual result:
--------------
A_&B_&C&D_&E__&F__&G___&
("_" means an invalid byte)

-- 
Edit bug report at http://bugs.php.net/?id=49785&edit=1
-- 
Try a snapshot (PHP 5.2):            
http://bugs.php.net/fix.php?id=49785&r=trysnapshot52
Try a snapshot (PHP 5.3):            
http://bugs.php.net/fix.php?id=49785&r=trysnapshot53
Try a snapshot (PHP 6.0):            
http://bugs.php.net/fix.php?id=49785&r=trysnapshot60
Fixed in SVN:                        
http://bugs.php.net/fix.php?id=49785&r=fixed
Fixed in SVN and need be documented: 
http://bugs.php.net/fix.php?id=49785&r=needdocs
Fixed in release:                    
http://bugs.php.net/fix.php?id=49785&r=alreadyfixed
Need backtrace:                      
http://bugs.php.net/fix.php?id=49785&r=needtrace
Need Reproduce Script:               
http://bugs.php.net/fix.php?id=49785&r=needscript
Try newer version:                   
http://bugs.php.net/fix.php?id=49785&r=oldversion
Not developer issue:                 
http://bugs.php.net/fix.php?id=49785&r=support
Expected behavior:                   
http://bugs.php.net/fix.php?id=49785&r=notwrong
Not enough info:                     
http://bugs.php.net/fix.php?id=49785&r=notenoughinfo
Submitted twice:                     
http://bugs.php.net/fix.php?id=49785&r=submittedtwice
register_globals:                    
http://bugs.php.net/fix.php?id=49785&r=globals
PHP 4 support discontinued:          http://bugs.php.net/fix.php?id=49785&r=php4
Daylight Savings:                    http://bugs.php.net/fix.php?id=49785&r=dst
IIS Stability:                       
http://bugs.php.net/fix.php?id=49785&r=isapi
Install GNU Sed:                     
http://bugs.php.net/fix.php?id=49785&r=gnused
Floating point limitations:          
http://bugs.php.net/fix.php?id=49785&r=float
No Zend Extensions:                  
http://bugs.php.net/fix.php?id=49785&r=nozend
MySQL Configuration Error:           
http://bugs.php.net/fix.php?id=49785&r=mysqlcfg

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