On 2/7/2025 2:20 AM, Dr. Greg wrote:

On Thu, Feb 06, 2025 at 10:48:57AM -0500, Paul Moore wrote:

Good morning to everyone.

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On Wed, Feb 5, 2025 at 7:01???AM Dr. Greg [off-list ref] wrote:

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On Tue, Jan 28, 2025 at 05:23:52PM -0500, Paul Moore wrote:

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I believe the LSM can support both the enforcement of security policy
and the observation of security relevant events on a system.  In fact
most of the existing LSMs do both, at least to some extent.

However, while logging of security events likely needs to be
asynchronous for performance reasons, enforcement of security policy
likely needs to be synchronous to have any reasonable level of
assurance.  You are welcome to propose LSMs which provide
observability functionality that is either sync, async, or some
combination of both (? it would need to make sense to do both ?), but
I'm not currently interested in accepting LSMs that provide
asynchronous enforcement as I don't view that as a "reasonable"
enforcement mechanism.

This is an artificial distinction that will prove limiting to the
security that Linux will be able to deliver in the future.

Based on your response, is it your stated position as Linux security
maintainer, that you consider modern Endpoint Detection and Response
Systems (EDRS) lacking with respect to their ability to implement a
"reasonable" enforcement and assurance mechanism?

As stated previously: "I'm not currently interested in accepting
LSMs that provide asynchronous enforcement as I don't view that as a
reasonable enforcement mechanism."

You personally don't, the IT and security compliance industry does, it
seems to leave Linux security infrastructure in an interesting
conundrum.

For the record, just to be very clear as to what an LSM is allowed to
do under your administration, for our benefit and the benefit of
others:

An LSM asynchronously streams an encoding of every security event that
occurs into something in userspace, somewhere, that interprets those
events.  Is userspace allowed to directly signal the operating system
if it detects an anomaly in one of those events or a pattern of events
and at what resolution level can the signalling occur?

Not to throw a wet blanket on your argument, but you can do just that
with a combination of the audit trail and Smack. Well, mostly. You can't
retroactively deny an access, but you can change the Smack label on a
file or change the access rules as desired. What you can't do is detain
an event while user space is queried about the decision. That is, I
believe, the fundamental problem with your approach.

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If this is the case, your philosophy leaves Linux in a position that
is inconsistent with how the industry is choosing to implement
security.

In this case perhaps TSEM is not well suited for the upstream Linux
kernel and your efforts are better spent downstream, much like the
industry you appear to respect.

Fascinating response from someone given the privilege of
maintainership status of a sub-system in a project whose leadership
preaches the need to always work with and submit to upstream.

"Work with" sometimes means you don't get everything you thought you
wanted in the way you wanted it. Refer to the work on LSM stacking,
which looks very different now than it did when I started on it in 2010.

Even more fascinating when that individual publically states that he
is employed by the largest technology company in the world because of
that companies desire to promote the health and well being of the
Linux eco-system and community.

For the record, we don't respect any industry, we respect the need to
address the challenges associated with how we are currently doing and
thinking about things.

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paul-moore.com

Our apologies to everyone for being a voice crying out in the
wilderness.

You aren't crying anything new. It's not easy to address all of the
issues necessary to make a chunk of code acceptable to the Linux
kernel. I doesn't help that you're crying in a language in which much
of your audience is not fluent.

As always,
Dr. Greg

The Quixote Project - Flailing at the Travails of Cybersecurity
              https://github.com/Quixote-Project