[Freeipa-devel] [DESIGN] Time-Based HBAC Policies

[Petr Spacek]

On 18.5.2016 12:52, Jan Cholasta wrote:
> On 18.5.2016 12:43, Stanislav Laznicka wrote:
>> On 05/18/2016 12:38 PM, Jan Cholasta wrote:
>>> On 18.5.2016 12:23, Petr Spacek wrote:
>>>> On 18.5.2016 08:25, Stanislav Laznicka wrote:
>>>>> On 05/17/2016 12:40 PM, Petr Spacek wrote:
>>>>>> On 13.5.2016 13:50, Stanislav Laznicka wrote:
>>>>>>> Hello list,
>>>>>>>
>>>>>>> We had a discussion today over integrating the Time Rules into the
>>>>>>> CLI and
>>>>>>> WebUI and a problem came up with with the current solution. It
>>>>>>> seems that
>>>>>>> while having templating handled by CoSTemplates might be nice in
>>>>>>> terms of easy
>>>>>>> dereferencing on SSSD side (it's handled by the DS itself), it's
>>>>>>> not really
>>>>>>> much possible to pick one string from the multi-valued accesstime
>>>>>>> attribute of
>>>>>>> HBAC Rule object and modify it.
>>>>>> Could you be more specific?
>>>>>>
>>>>>> AFAIK LDAP protocol allows this. Where is the problem?
>>>>>>
>>>>>> Petr^2 Spacek
>>>>> I should have added we're talking CLI and WebUI here.
>>>>>
>>>>> Imagine you have 5 values of the accesstime attribute, each one is
>>>>> about 10
>>>>> lines of iCal string, and want to change one:
>>>>>
>>>>> ipa hbacrule-mod-accesstime rule_name --time=???
>>>>
>>>> I see. In DNS plugin we do it this way:
>>>> https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Linux_Domain_Identity_Authentication_and_Policy_Guide/managing-master-dns-zones.html#examples-add-modify-record-cli
>>>>
>>>>
>>>>
>>>> $ ipa dnsrecord-mod example.com www --a-rec 192.0.2.123
>>>> --a-ip-address 192.0.2.1
>>>>
>>>> I would argue that naming of the options is weird so something easier to
>>>> understand could be made. E.g.
>>>> $ ipa hbacrule-mod-accesstime rule_name --orig-time=??? --time=???
>>>
>>> NACK, the dns plugin should not be used as an example for anything, as
>>> it breaks almost every convention in the framework.

Good point :-)

>> Also, typical iCalendar string is not much suitable for this approach
>> (see http://tools.ietf.org/html/rfc5545#section-4 for examples). Your
>> proposal is a way, of course, but not much user-friendly here.
>>>
>>> Removing and adding of particular accesstime values should be done by
>>> a pair of commands, "hbacrule-add-accesstime rule_name accesstime" and
>>> "hbacrule-remove-accesstime rule_name accesstime".
>>>
>> What about modifications, thought? If not for CLI, you will still need a
>> way to modify a more complex time rule in the WebUI (you do not want to
>> remove a complex rule just to click through its creation all again for a
>> minor change).
> 
> Modification of an attribute value is exactly that - the old value gets
> removed and the new value gets added. How it will look like in the web UI is a
> completely different thing.

The question here is if the intermediate state without defined time (remember,
no transactions!) is acceptable or not.

Does it mean that the time restriction will removed OR that access will be
always denied because the rule is incomplete?

Petr^2 Spacek

> 
>>>>
>>>>>>> We were thinking of a solution discussed way earlier - having our
>>>>>>> own time
>>>>>>> rule objects that could be referenced from each HBAC rule. That
>>>>>>> way, any time
>>>>>>> rule could be modified easily. As the HBAC rules are cached on the
>>>>>>> SSSD side
>>>>>>> periodically using the deref plugin, there should be no problem of
>>>>>>> inconsistency with the server database.
>>>>>>>
>>>>>>> The original reasoning pro and against the proposed solution could
>>>>>>> be found on
>>>>>>> the pad
>>>>>>> http://pad.engineering.redhat.com/ipa-time-based-HBAC-design. It
>>>>>>> would
>>>>>>> be really nice to hear your opinions and ideas that could help us
>>>>>>> overcome
>>>>>>> this problem.
>>>>>>>
>>>>>>> Thank you,
>>>>>>> Standa