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

[Stefan Berger]

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