[Freeipa-devel] [PATCH] 971 detect binary LDAP data

[Rob Crittenden]

Rob Crittenden wrote:
> Simo Sorce wrote:
>> On Mon, 2012-02-27 at 09:44 -0500, Rob Crittenden wrote:
>>> We are pretty trusting that the data coming out of LDAP matches its
>>> schema but it is possible to stuff non-printable characters into most
>>> attributes.
>>>
>>> I've added a sanity checker to keep a value as a python str type
>>> (treated as binary internally). This will result in a base64 encoded
>>> blob be returned to the client.
>>
>> Shouldn't you try to parse it as a unicode string and catch TypeError to
>> know when to return it as binary ?
>>
>> Simo.
>>
>
> What we do now is the equivalent of unicode(chr(0)) which returns
> u'\x00' and is why we are failing now.
>
> I believe there is a unicode category module, we might be able to use
> that if there is a category that defines non-printable characters.
>
> rob

Like this:

import unicodedata

def contains_non_printable(val):
     for c in val:
         if unicodedata.category(unicode(c)) == 'Cc':
             return True
     return False

This wouldn't have the exclusion of tab, CR and LF like using ord() but 
is probably more correct.

rob