Re: [PATCH] audit: add containerid support for IMA-audit

[Stefan Berger <stefanb@linux.vnet.ibm.com>]

On 05/18/2018 08:53 AM, Mimi Zohar wrote:
> On Fri, 2018-05-18 at 07:49 -0400, Stefan Berger wrote:
>> On 05/17/2018 05:30 PM, Richard Guy Briggs wrote:
> [...]
>
>>>>> auxiliary record either by being converted to a syscall auxiliary record
>>>>> by using current->audit_context rather than NULL when calling
>>>>> audit_log_start(), or creating a local audit_context and calling
>>>> ima_parse_rule() is invoked when setting a policy by writing it into
>>>> /sys/kernel/security/ima/policy. We unfortunately don't have the
>>>> current->audit_context in this case.
>>> Sure you do.  What process writes to that file?  That's the one we care
>>> about, unless it is somehow handed off to a queue and processed later in
>>> a different context.
>> I just printk'd it again. current->audit_context is NULL in this case.
> The builtin policy rules are loaded at __init.  Subsequently a custom
> policy can replace the builtin policy rules by writing to the
> securityfs file.  Is the audit_context NULL in both cases?

The builtin policy rules are not parsed from what I can see. They seem 
to be encoded in the format the parser would produce.

I get current->audit_context == NULL in the case the user cat's the 
policy into IMA's policy securityfs file.

>
>
>
>>>> 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.

> INTEGRITY_AUDIT or INTEGRITY_IMA_AUDIT?  The new type=1806 audit
> message could be named INTEGRITY_RULE or, if that would be confusing,
> INTEGRITY_POLICY_RULE.

For 1806, as we would use it in ima_parse_rule(), we could change that 
in your patch to INTEGRITY_POLICY_RULE. IMA_POLICY_RULE may be better 
for IMA to produce but that's inconsistent then.

>
>> 1806 would be in sync with INTEGRITY_RULE now for process related info.
>> If this looks good, I'll remove the dependency on your local context
>> creation and post the series.
>>
>> The justification for the change is that the INTEGRITY_RULE, as produced
>> by ima_parse_rule(), is broken.
> Post which series?  The IMA namespacing patch set?  This change should
> be upstreamed independently of IMA namespacing.

Without Richard's local context patch it may just be one or two patches.

    Stefan

>
> Mimi