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

[Martin Basti]

On 26.08.2016 12:37, Petr Vobornik wrote:
> On 08/26/2016 12:23 PM, Martin Basti wrote:
>>
>> On 26.08.2016 12:20, Alexander Bokovoy wrote:
>>> On Fri, 26 Aug 2016, Jan Cholasta wrote:
>>>> On 26.8.2016 11:55, Martin Basti wrote:
>>>>>
>>>>> On 26.08.2016 11:43, Jan Cholasta wrote:
>>>>>> Hi,
>>>>>>
>>>>>> On 11.8.2016 12:34, Stanislav Laznicka wrote:
>>>>>>> Hello,
>>>>>>>
>>>>>>> I updated the design of the Time-Based HBAC Policies according to the
>>>>>>> discussion we led here earlier. Please check the design page
>>>>>>> http://www.freeipa.org/page/V4/Time-Based_Account_Policies. The
>>>>>>> biggest
>>>>>>> changes are in the Implementation and Feature Management sections. I
>>>>>>> also added a short How to Use section.
>>>>>> 1) Please use the 'ipa' prefix for new attributes: memberTimeRule ->
>>>>>> ipaMemberTimeRule
>>>>>>
>>>>>>
>>>>>> 2) Source hosts are deprecated and thus should be removed from
>>>>>> ipaHBACRuleV2.
>>>>>>
>>>>>>
>>>>>> 3) Since time rules are defined by memberTimeRule, accessTime should
>>>>>> be removed from ipaHBACRuleV2.
>>>>> ad 2) 3)
>>>>>
>>>>> Because backward compatibility, ipaHBACRuleV2 must contain all
>>>>> attributes from ipaHBACRule as MAY
>>>> Not true.
>>>>
>>>>> With current approach, when timerule is added to HBAC, we just change
>>>>> objectclass from 'ipahbacrule' to 'ipahbacrulev2' so we keep all
>>>>> attributes that was defined in older HBAC. Removing any attrs from
>>>>> ipaHBACRuleV2 can cause schema violation.
>>>> Which is perfectly fine.
>>>>
>>>>>
>>>>> I'm not sure if want to handle this in code (removing deprecated
>>>>> attributes from HBAC entry when timerule is added)
>>>> We don't have to do anything. If any of the deprecated attributes are
>>>> present when you change the object class (which they shouldn't
>>>> anyway), you'll get schema violation, otherwise it will work just fine.
>>>>
>>>>> I realized that AccessTime is MUST for 'ipahbacrule', so when timerule
>>>>> ('ipahbacrulev2') is removed and somebody deleted accesstime we have to
>>>>> add it back.
>>>> It is MAY. The only MUST attribute is accessRuleType, but that is
>>>> deprecated as well and should be removed from ipaHBACRuleV2. We only
>>>> support allow rules, so when timerule is removed, that's the value
>>>> you set accessRuleType to.
>>> SSSD does search for HBAC rules by '(objectclass=ipaHBACRule)' filter.
>>> Changing to ipaHBACRuleV2 means these rules will not be found by older
>>> SSSD versions and therefore people will experience problems with older
>>> clients not being able to use new rules even if they would lack time
>>> component.
>>>
>> Older client do not support timerules, so they should not search for
>> them. HBAC without timerules will be still have 'ipaHBACRule'
>> objectclass and will work with old clients. Only HBAC with timerules
>> will have assigned 'ipaHBACRuleV2'
>>
>> Martin^2
> I miss "why" part of "To be able to handle backward compatibility with
> ease, a new object called ipaHBACRulev2 is introduced. " in the design
> page. If the reason is the above - old client's should ignore time rules
> then it has to be mentioned there. Otherwise I don't see a reason to
> introduce a new object type instead of extending the current.

How do you want to enforce HBAC rule that have set time from 10 to 14 
everyday? With the same objectclass old clients will allow this HBAC for 
all day. Isn't this CVE?

>
>
> 2. About API and CLI: wasn't there an idea to hide/not provide
> --icalfile=file.ics and --time=escaped_icalstring  options in the first
> implementation. So that we can limit the support scope to only a subset
> of option(the  OPTS part). If arbitrary ical is allowed since the
> beginning then we are asking for a lot of bugs filed.
>