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Subject: Re: [PATCH] audit: add containerid support for IMA-audit
To:     Steve Grubb <sgrubb@redhat.com>,
        Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc:     Richard Guy Briggs <rgb@redhat.com>,
        containers@lists.linux-foundation.org,
        Linux-Audit Mailing List <linux-audit@redhat.com>,
        linux-integrity <linux-integrity@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, paul@paul-moore.com
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From:   Stefan Berger <stefanb@linux.vnet.ibm.com>
Date:   Mon, 21 May 2018 14:04:08 -0400
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On 05/21/2018 01:21 PM, Steve Grubb wrote:
> On Friday, May 18, 2018 12:34:24 PM EDT Mimi Zohar wrote:
>> On Fri, 2018-05-18 at 11:56 -0400, Richard Guy Briggs wrote:
>>> On 2018-05-18 10:39, Mimi Zohar wrote:
>>>> On Fri, 2018-05-18 at 09:54 -0400, Stefan Berger wrote:
>>>>> On 05/18/2018 08:53 AM, Mimi Zohar wrote:
>>>> [..]
>>>>
>>>>>>>>> If so, which ones? We could probably refactor the current
>>>>>>>>> integrity_audit_message() and have ima_parse_rule() call into it
>>>>>>>>> to get
>>>>>>>>> those fields as well. I suppose adding new fields to it wouldn't
>>>>>>>>> be
>>>>>>>>> considered breaking user space?
>>>>>>>> Changing the order of existing fields or inserting fields could
>>>>>>>> break
>>>>>>>> stuff and is strongly discouraged without a good reason, but
>>>>>>>> appending
>>>>>>>> fields is usually the right way to add information.
>>>>>>>>
>>>>>>>> There are exceptions, and in this case, I'd pick the "more
>>>>>>>> standard" of
>>>>>>>> the formats for AUDIT_INTEGRITY_RULE (ima_audit_measurement?) and
>>>>>>>> stick
>>>>>>>> with that, abandoning the other format, renaming the less
>>>>>>>> standard
>>>>>>>> version of the record (ima_parse_rule?) and perhpas adopting that
>>>>>>>> abandonned format for the new record type while using
>>>>>>>> current->audit_context.
>>>>>> This sounds right, other than "type=INTEGRITY_RULE" (1805) for
>>>>>> ima_audit_measurement().  Could we rename type=1805 to be
>>>>> So do we want to change both? I thought that what
>>>>> ima_audit_measurement() produces looks ok but may not have a good
>>>>> name
>>>>> for the 'type'. Now in this case I would not want to 'break user
>>>>> space'.
>>>>> The only change I was going to make was to what ima_parse_rule()
>>>>> produces.
>>>> The only change for now is separating the IMA policy rules from the
>>>> IMA-audit messages.
>>>>
>>>> Richard, when the containerid is appended to the IMA-audit messages,
>>>> would we make the audit type name change then?
>>> No, go ahead and make the change now.  I'm expecting that the
>>> containerid record will just be another auxiliary record and should not
>>> affect you folks.
>> To summarize, we need to disambiguate the 1805, as both
>> ima_parse_rule() and ima_audit_measurement() are using the same number
>> with different formats.  The main usage of 1805 that we are aware of
>> is ima_audit_measurement().  Yet the "type=" name for
>> ima_audit_measurement() should be INTEGRITY_IMA_AUDIT, not
>> INTEGRITY_RULE.
>>
>> option 1: breaks both uses
>> 1805 - INTEGRITY_IMA_AUDIT - ima_audit_measurement()
>> 1806 - INTEGRITY_POLICY_RULE - ima_parse_rule()
>>
>> option 2: breaks the most common usage
>> 1805 - INTEGRITY_RULE - ima_parse_rule()
>> 1806 - INTEGRITY_IMA_AUDIT - ima_audit_measurement()
>>
>> option 3: leaves the most common usage with the wrong name, and breaks
>> the other less common usage
>> 1805 - INTEGRITY_RULE - ima_audit_measurement()
>> 1806 - INTEGRITY_POLICY_RULE - ima_parse_rule()
>>
>> So option 3 is the best option?
>  From a user space perspective, I don't care as long the event is well formed

Are you saying this because of the tools you referred to that require 
proper ordering and all fields need to be available?

> (No unnecessary untrusted string logging) and we have the required fields for
> searching: pid, uid, auid, tty, session, subj, comm, exe, & res. And the
> object is identifiable in the event.

There's at least one documented user that showed the existing format...

https://www.fireeye.com/blog/threat-research/2016/11/extending_linux_exec.html