[PATCH v10 10/27] ima: Move IMA securityfs files into ima_namespace or onto stack

[Mimi Zohar]

On Tue, 2022-02-01 at 15:37 -0500, Stefan Berger wrote:
> Earlier we simplified how dentry creation and deletion is manged in
> securityfs. This allows us to move IMA securityfs files from global
> variables directly into ima_fs_ns_init() itself. We can now rely on
> those dentries to be cleaned up when the securityfs instance is cleaned
> when the last reference to it is dropped.
> 
> Things are slightly different for the initial IMA namespace. In contrast
> to non-initial IMA namespaces it has pinning logic binding the lifetime
> of the securityfs superblock to created dentries. We need to keep this
> behavior to not regress userspace. Since IMA never removes most of the
> securityfs files the initial securityfs instance stays pinned. This also
> means even for the initial IMA namespace we don't need to keep
> references to these dentries anywhere.
> 
> The ima_policy file is the exception since IMA can end up removing it
> on systems that don't allow reading or extending the IMA custom policy.
> 
> Signed-off-by: Stefan Berger <stefanb at linux.ibm.com>
> Acked-by: Christian Brauner <brauner at kernel.org>

Really nicely worded patch description.  Thanks!

Reviewed-by: Mimi Zohar <zohar at linux.ibm.com>