[Freeipa-devel] [DESIGN] FreeIPA on FIPS + NSS question

Wed Jan 25 11:46:00 UTC 2017

On 01/13/2017 05:44 PM, Petr Vobornik wrote:
> On 01/13/2017 03:49 PM, Rob Crittenden wrote:
>> Tomas Krizek wrote:
>>> On 01/12/2017 04:17 PM, Rob Crittenden wrote:
>>>> Tomas Krizek wrote:
>>>>> On 12/19/2016 04:41 PM, Standa Laznicka wrote:
>>>>>> On 12/19/2016 03:07 PM, John Dennis wrote:
>>>>>>> On 12/19/2016 03:12 AM, Standa Laznicka wrote:
>>>>>>>> On 12/16/2016 03:23 PM, Rob Crittenden wrote:
>>>>>>>>> Standa Laznicka wrote:
>>>>>>>>>> Hello,
>>>>>>>>>>
>>>>>>>>>> I started a design page for FreeIPA on FIPS-enabled systems:
>>>>>>>>>> https://www.freeipa.org/page/V4/FreeIPA-on-FIPS
>>>>>>>>>>
>>>>>>>>>> Me and Tomáš are still investigating what of all things will need to
>>>>>>>>>> change in order to have FreeIPA on FIPS-enabled RHEL. So far I
>>>>>>>>>> managed
>>>>>>>>>> to install and run patched FreeIPA server and client and connect them
>>>>>>>>>> together.
>>>>>>>>>>
>>>>>>>>>> There are some issues with NSS when trying to create an HTTPS request
>>>>>>>>>> (apparently, NSS requires an NSS database password to set up an SSL
>>>>>>>>>> connection). I am actually thinking of removing NSSConnection from
>>>>>>>>>> the
>>>>>>>>>> client altogether.
>>>>>>>>> Can you expand on this a bit? NSS should only need a pin when it needs
>>>>>>>>> access to a private key. What connection(s) are you talking about, and
>>>>>>>>> what would you replace NSSConnection with?
>>>>>>>>>
>>>>>>>>> rob
>>>>>>>> Hello Rob,
>>>>>>>>
>>>>>>>> Thank you for this excellent question, in order to cut the email
>>>>>>>> short I
>>>>>>>> seem to have omitted quite a few information.
>>>>>>>>
>>>>>>>> One of the very first problems I had with FreeIPA with FIPS was that
>>>>>>>> NSS
>>>>>>>> was always asking for password/pin. I was discussing this with the NSS
>>>>>>>> guys on their IRC chat last week and it turns out that NSS tries to
>>>>>>>> create a private key every time you want to use it as a backend for an
>>>>>>>> SSL connection on FIPS. I still don't think this is quite right so I
>>>>>>>> may
>>>>>>>> open a bugzilla for that.
>>>>>>> I don't understand, I thought the case you were having problems with
>>>>>>> was the FreeIPA client, not the server. I assume when you use the
>>>>>>> term "backend" you mean server, and yes when NSS is in server mode it
>>>>>>> will access to keys. So isn't the problem NSS is not being
>>>>>>> initialized correctly so that it recognizes it is in client mode and
>>>>>>> not server mode?
>>>>>>>
>>>>>> What I meant was "a client backend for an SSL connection" - we're
>>>>>> using NSS implementation of SSL (via python-nss) for HTTPS connections
>>>>>> from client to server during which we're getting a CA cert from an NSS
>>>>>> database but this eventually leads to a password prompt.
>>>>>>>> Anyway, the guys suggested me that we could try to create the database
>>>>>>>> with an empty password and everything will work. I don't quite like
>>>>>>>> that, too, but it's at least something if you don't want the `ipa`
>>>>>>>> command to always bug you for password you have no way knowing if
>>>>>>>> you're
>>>>>>>> just a regular user.
>>>>>>>>
>>>>>>>> What I think would be a better way to go is to use
>>>>>>>> httplib.HTTPSConnection. We have the needed certificates in
>>>>>>>> /etc/ipa/ca.crt anyway so why not use them instead. We had a discussion
>>>>>>>> with Honza this morning and it seems that with this approach we may get
>>>>>>>> rid of the NSSConnection class altogether (although I still need to
>>>>>>>> check a few spots) and start the process of moving away from NSS which
>>>>>>>> was discussed some year ago in an internal mailing list (for some
>>>>>>>> reason).
>>>>>>>>
>>>>>>>> Will be happy to hear thoughts on this,
>>>>>>>> Standa
>>>>>>> I'm not a big fan of NSS, it has it's issues. As the author of the
>>>>>>> Python binding I'm quite aware of all the nasty behaviors NSS has and
>>>>>>> needs to be worked around. I wouldn't be sad to see it go but OpenSSL
>>>>>>> has it's own issues too. If you remove NSS you're also removing the
>>>>>>> option to support smart cards, HSM's etc. Perhaps before removing
>>>>>>> functionality it would be good to assess what the requirements are.
>>>>>>>
>>>>>> I'm sorry I generalized too much, the original topic was moving away
>>>>>> from python-nss (of which I am even more sorry as you're the author).
>>>>>>
>>>>> We could use some ideas on how to handle replica installations in FIPS.
>>>>>
>>>>> We might use some flag in LDAP to indicate that a topology is
>>>>> FIPS-enabled. It seems like a good idea to force all servers in
>>>>> FIPS-enabled topology to also be FIPS-enabled. At the start of replica
>>>>> installation, a check could be performed to verify the FIPS topology
>>>>> status is the same as the current system's FIPS status. However, this
>>>>> proposal has a flaw. It is possible to simply install a FIPS-enabled
>>>>> replica and then turn FIPS off. This would result in non-FIPS systems
>>>>> being part of a FIPS-enabled topology.
>>>>>
>>>>> So we have a couple questions:
>>>>>
>>>>> Does it make sense to require all the servers in the topology to be
>>>>> either FIPS-enabled or FIPS-disabled?
>>>>> What would be a good approach to achieve this? Simply checking during
>>>>> installation does not guarantee that FIPS will stay turned on.
>>>>>
>>>> You could set some value in the replicated tree on FIPS status and write
>>>> a 389-ds plugin to refuse to start if the environment doesn't match.
>>>> Given this is started first it should cause a cascade of failures so no
>>>> services are available.
>>>>
>>>> rob
>>> Based on an offline discussion, we might just omit this feature
>>> entirely. Our goal is to enable FreeIPA installation of FIPS configured
>>> systems. It should be up to the customer to make sure other FIPS
>>> requirements are met, i.e. all servers are configured to use FIPS.
>>>
>> Up to you but this is bound to be an RFE and seems like quite a weakness
>> to me.
>>
>> You'll want to be sure to enforce that any additional masters get FIPS
>> by default if the initial master has it. In other words, they shouldn't
>> need to remember to pass an option, it should be automatic.
>>
>> rob
>>
> +1 to Rob.
>
> We could operate between the two extremes:
>   * Extreme 1: Ensuring that FIPS will remain enabled on all existing
> replica.
>   * Extreme 2: Do not validate anything
>
> I.e. we could only:
>   * Note in LDAP that first server was installed with FIPS
>   * Check it at install time
>         - prevent from installation of non-FIPS
>         - prevent from installation of FIPS replica in non-FIPS topology
>
> It won't be bullet proof but it will check major mistakes which the
> admin can do by accident.
I've updated the design document [1], sections Multiple Servers in
Topology (in Design and Implementation).

Instead of the originally proposed LDAP flag, we are proposing to check
//proc/sys/crypto/fips_enabled /on the master (via RPC call) and on
replica. Installation will proceed only if these match. See the design
for more details.

[1] - http://www.freeipa.org/page/V4/FreeIPA-on-FIPS

-- 
Tomas Krizek

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