[Freeipa-users] Bypass pre-hashed passwords verification

[Petr Vobornik]

On 07/22/2016 11:42 AM, Sébastien Julliot wrote:
> Hello everyone,
> 
> I am currently trying to deploy FreeIPA as the new idm system in my
> university but came across a problem I could not solve yet. I need to
> bypass the pre-hashed passwords verification, not only on the user creation.
> 
> Due to several constraints, our workflow involves periodically (once a
> day, currently) receiving an ldif file containing the users up-to-date
> informations, (including hashed passwords) and inserting this
> informations into the idm. As our goal is to unify users passwords in
> the university but do not have access to the higher-level LDAP directly,
> we injected this pre-hashed passwords directly into the LDAP until today.
> 
> Yet, every attempt I made to update users passwords with pre-hashed
> passwords failed for now.
> 
> First I tried this (migration mode enabled):
> 
> ➜  ~ ipa user-add testuser --first=test --last=user --setattr userpassword='{MD5}*********************'
> 
> /*OK*/
> 
> ➜  ~ kinit testuser
> 
> kinit: Generic preauthentication failure while getting initial credentials
> 
> As expected from the documentation, it does not work :p
> 
> I then thought about trying to copy the migration plug-in, and change
> the way it retrieves users (from LDIF rather than from an online LDAP
> server). Since this plugin is able to  But again, event binding as
> Directory Manager, the ipa ldap2 backend method add_entry refuses me (I
> tested my code without the userPassword field and the users are
> correctly inserted).
> 
> Here is my code :
> 
> class ldif_importer(ldif.LDIFParser):
>     def __init__(self, ldap_backend):
>         ldif.LDIFParser.__init__(self, open('test.ldif', 'rb'))
>         self.ldap = ldap_backend
> 
>     def handle(self, dn, entry):
>         self.ldap.add_entry(self.ldap.make_entry(DN(dn), entry))
> 
> class my_backend(ipalib.Backend):
>     '''Backend to import ldap passwords from ldif'''
> 
>     def __init__(self, api):
>         ipalib.Backend.__init__(self, api)
>         self.ldap = ldap2(self.api)
>         self.ldap.connect(bind_dn=DN('cn=Directory Manager'), bind_pw='***********')
> 
>     def parse(self):
>         importer = ldif_importer(self.ldap)
>         importer.parse()
> 
> class my_command(ipalib.Command):
>     '''Command calling my_backend to import passwords from ldif'''
> 
>     def execute(self, **options):
>         '''Implemented against my_backend'''
>         self.Backend.my_backend.parse()
>         return {'result': 'everything OK'}
> 
> 
> Should one of these methods have worked, and I did it incorrectly ?
> Otherwise, what would be the lower-impact solution to achieve this ?
> (Yes, I understand the security concerns about sending passwords hashes
> on the network but this choice does not depend on me)
> 
> Many thanks in advance,
> Sebastien.
> 

I issue might be that the user has his userPassword migrated but he
doesn't have krbPrincipalKey generated. If kerberos key is missing then
it is automatically generated on successful LDAP bind (it's what
ipa/migration page does)

Additional info which might interest you:
*
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Windows_Integration_Guide/pass-sync.html#password-sync
* http://www.freeipa.org/page/NIS_accounts_migration_preserving_Passwords

-- 
Petr Vobornik