[PATCH] init/main.c: Initialize early LSMs after arch code

[Guenter Roeck]

On Thu, Aug 08, 2024 at 01:32:37PM -0400, Paul Moore wrote:
> On Thu, Aug 8, 2024 at 12:43 PM Guenter Roeck <linux at roeck-us.net> wrote:
> >
> > Also, there is a backtrace on ppc (also see below), but that is unrelated
> > to your patches and only seen now because I enabled the security modules
> > on that architecture. I'll bring that up with ppc maintainers.
> 
> Thanks for all your help testing this Guenter.  I see you've also
> already submitted an AppArmor fix for the endian issue, that's very
> helpful and I'm sure John will be happy to see it.
> 
> Beyond this work testing the static call patches from KP, would you be
> willing to add a LSM configuration to your normal testing?  While most
> of the LSM subsystem should be architecture agnostic, there are
> definitely bits and pieces that can vary (as you've seen), and I think
> it would be great to get more testing across a broad range of
> supported arches, even if it is just some simple "does it boot" tests.
> 

That really depends. I already enabled some of the kernel security modules.

CONFIG_SECURITY=y
CONFIG_SECURITY_APPARMOR=y
CONFIG_SECURITY_APPARMOR_KUNIT_TEST=y
CONFIG_SECURITY_LANDLOCK=y
CONFIG_SECURITY_LANDLOCK_KUNIT_TEST=y
CONFIG_SECURITY_LOCKDOWN_LSM=y
CONFIG_SECURITY_LOCKDOWN_LSM_EARLY=y
CONFIG_SECURITY_YAMA=y
CONFIG_SECURITY_LOADPIN=y
CONFIG_SECURITY_SAFESETID=y
CONFIG_BPF_LSM=y
CONFIG_LSM="landlock,lockdown,yama,loadpin,safesetid,bpf"

I can easily add more if you tell me what else I should enable.

Userspace is more difficult. My root file systems are generated using
buildroot. I run some basic tests, such as network interface tests
and TPM tests, but those are just simple scripts utilizing packages
provided by buildroot. I can add more, but I would need to know what
exactly to add and how to execute it.

In general my tests are intended to cover a large number of different
configurations; they are intended to be broad, not deep. That means an
individual test should not take longer than a couple of seconds. If you
can provide something that would run in the buildroot environment and
not take long to execute (example: tpm2 selftests), I'd be happy to add
it.

For more comprehensive tests, it might make sense to discuss adding
security tests to KernelCI; they have much more resources available
and target deeper testing. That would make sense if you have, for example,
test suites to run on upstream kernels or stable release candidates. 

> Out of curiosity, do you have your test setup documented anywhere?  It
> sounds fairly impressive and I'd be curious to learn more about it.
> 

Not really. The code is at https://github.com/groeck/linux-build-test.
My clone of buildroot is at https://github.com/groeck/buildroot (look
for local- branches to see my changes). Please feel free to have a look,
but documentation is seriously lacking (and README is completely out
of date).

Guenter