Re: [RFC][PATCH] audit: log join and part events to the read-only multicast log socket

Steve Grubb
2014-10-22T20:39:49Z

On Wednesday, October 22, 2014 04:06:47 PM Paul Moore wrote:
> On Wednesday, October 22, 2014 01:56:13 PM Steve Grubb wrote:
> > On Wednesday, October 22, 2014 11:28:46 AM Paul Moore wrote:
> > > On Wednesday, October 22, 2014 10:25:35 AM Steve Grubb wrote:
> > > > On Tuesday, October 21, 2014 06:30:24 PM Paul Moore wrote:
> > > > > This is getting back to my earlier concerns/questions about field
> > > > > ordering, or at the very least I'm going to hijack this conversation
> > > > > and steer it towards field ordering ;)
> > > >
> > > > Field ordering is important. For example, suppose we decide to make
> > > > ordering changes to the AUDIT_AVC record to bring it in line with
> > > > current standards. Would anyone care?
> > >
> > > That is an interesting example record considering everyone recognizes it
> > > to be an oddly formed, special case.
> >
> > But it illustrates the point. There are tools that depend on an ordering
> > and format. There are more programs that just ausearch that needs to be
> > considered if the fields change. For example, Someone could do things
> > like this:
> >
> > retval = auparse_find_field(au, "auid");
> > retval = auparse_next_field(au);
> > retval = auparse_next_field(au);
> > retval = auparse_find_field(au, res");
> >
> > Where, if the field ordering can't be guaranteed, the code becomes:
> >
> > retval = auparse_find_field(au, "auid");
> > retval = auparse_first_field(au);
> > retval = auparse_find_field(au, "pid");
> > retval = auparse_first_field(au);
> > retval = auparse_find_field(au, "uid");
> > retval = auparse_first_field(au);
> > retval = auparse_find_field(au, res");
>
> In my mind the latter code is more robust and preferable.

Except you can have problems when the event is like this
auid= pid= old uid= new uid= res=

and yes there are places like that. The performance really is the main issue.

> > Which of the two is likely to be faster? Especially when doing realtime
> > analysis as a plugin and needing to finish because another event is coming
> > in? Just like a binary struct has to maintain an order of data members if
> > written to disk, the sequence of fields need to be maintained in a text
> > record.
>
> What about the speed and performance of the code in the kernel?

kprintf is the same speed no matter what the order.

> What about the maintenance burden of having to duplicate code to ensure a
> fixed format?

There just isn't a need to be altering events. We've had to add a few things
here and there, but its only been a couple changes.

> > > > > Before we go to much farther, I'd really like us to agree that
> > > > > ordering is not important, can we do that?
> > > >
> > > > Its kind of doubtful we can do anything like this quickly. Maybe over
> > > > time.
> > >
> > > Why? Why can we not do this now?
> >
> > There are more pressing needs on the user space side of this. reordering
> > fields means I have to drop all my current plans and redo something that's
> > been working fine. This is why it takes so long to get audit utilities and
> > reports that are fast, understandable, and the right information.
>
> I disagree about the priority. Eric disagrees about the priority. Richard
> hasn't explicitly stated he disagrees with the priority but he has made
> several comments on this list about ordering being an issue (Richard, my
> apologies if I am putting words in your mouth).

What events do people need to change and why? There's not been any discussion
that I know of saying we need to add fields or change them around.

> Does the audit userspace still live in SVN on fedorahosted.org?

Yes.

> What would we need to change in the userspace to eliminate the reliance on
> field ordering?

Many of the utilities. ausyscall & autrace might be the only ones not affected.

> I understand if you don't have a well developed list of items,
> but surely you must have some idea?
>
> I'm willing to help here, and I suspect there might be some others as well,
> just let us know what the pressing issues are in the audit userspace.

People have been asking for
1) compressed logs
2) auparse needs to untangle interlaced events
3) people want to suppress certain records or events to save disk space
4) we need to handle federated IDs
5) we need to enrich events on the fly so that uids are preserved
6) we need a validation suite to ensure that user space apps are generating
correct events (lightdm for example is not audit aware meaning many desktops
can't be analyzed)
7) we need to get better at handling vast quantities of logs
8) we need some plugin for logstash
9) we need to allow people to format events their way
10) we need easier to understand reports
11) we need to be able to compare in kernel and on disk audit rules
12) auvirt is very broken and in need of rewrite
13) bash tab completions might be helpful
14) eventually combine audispd and auditd into 1 process.

There's more than that. But it would be nice of people using audit and its
tools also say what they are needing.

> > We shouldn't be doing much modifying of records. They really should be
> > pretty static unless requirements change. For new records, there is no
> > guarantee that the function created before is the right information for
> > the
> > new event. It just depends on what it is as to what needs to be collected.
> > Then due to all the misused fields, we still need to have review to make
> > sure there's no typo. Speaking of which, I just found a typo in
> > AUDIT_FEATURE_CHANGE events.
>
> We're seeing at least one case where our inability to change the ordering of
> the audit fields is causing problems.

What field ordering problem is preventing kernel work?

> > > > To me, these are the burning issues that I think should be on the
> > > > table
> > > > to be solved rather than field ordering:
> > > >
> > > > 1) ... {snip} ...
> > >
> > > Ignoring the priority for a moment, thanks for posting these. Is there
> > > an
> > > audit TODO list posted somewhere?
> >
> > That is just some kernel issues off the top of my head. Things come up all
> > the time. Most of the time things are found because someone is asking
> > questions or I am trying to make sense of the audit trail.
> >
> > As for user space tools, yes there is a TODO file in the audit tarball. I
> > don't know if the kernel maintainers have a TODO list published anywhere.
>
> Eric, do you have one published somewhere?
>
> Assuming that Eric doesn't have a TODO list posted somewhere, do you have
> any objections to my posting and maintaining an audit kernel TODO list on
> the audit fedorahosted.org wiki?

That would be nice.

-Steve