[PATCH v9 11/23] ima: Move ima_lsm_policy_notifier into ima_namespace

[Christian Brauner]

On Tue, Jan 25, 2022 at 05:46:33PM -0500, Stefan Berger wrote:
> From: Stefan Berger <stefanb at linux.ibm.com>
> 
> Move the ima_lsm_policy_notifier into the ima_namespace. Each IMA
> namespace can now register its own LSM policy change notifier callback.
> The policy change notifier for the init_ima_ns still remains in init_ima()
> and therefore handle the registration of the callback for all other
> namespaces in init_ima_namespace().
> 
> Signed-off-by: Stefan Berger <stefanb at linux.ibm.com>
> ---

I'd double-check that this cannot be used to cause rcu stalls when a lot
of ima namespace with a lot of rules are used leading to a dos situation
during LSM policy update. The good thing at least is that an LSM policy
update can only be triggered for selinux for the whole system.