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

[Stefan Berger]

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. ÂSubsequently a custom
> policy can replace the builtin policy rules by writing to the
> securityfs file. ÂIs 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(). ÂCould 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? ÂThe 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? ÂThe IMA namespacing patch set? ÂThis change should
> be upstreamed independently of IMA namespacing.

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

ÂÂ Stefan

> Mimi