Description:
------------
When data to be encrypted has some special chars the mcrypt_generic function breaks execution.

Reproduce code:
---------------
$wrong_data ="<?xml version='1.0' encoding='UTF-8'>
<root>
   <data>0123456789</data>
</root>";

$correct_data ="<? xml version='1.0' encoding='UTF-8'>
<root>
   <data>0123456789</data>
</root>";

//cypher
$mcrypt_cypher = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_ECB, '');

//initialization code: mcrypt with mcrypt_generic_init and a 256 key


//trying to encrypt the correct data
$cipherText_correct = mcrypt_generic($mcrypt_cypher, $correct_data);
echo $cipherText_correct;

//trying to encrypt the wrong data
$cipherText_wrong = mcrypt_generic($mcrypt_cypher, $wrong_data);
echo $cipherText_wrong;

Expected result:
----------------
Expected data to be correctly encrypted given it is just a simple string.

Actual result:
--------------
$correct_data is encrypted correctly. (with a space after "?" -> '<? xml')

$wrong_data simply breaks the execution. (without space after "?" -> '<?xml')


It is worth to know the code written above is correctly initialized and wrong_data and correct_data were 2 different executions.