Keys queued for measurement should be freed if a custom IMA policy
was not loaded.  Otherwise, the keys will remain queued forever
consuming kernel memory.

This patch defines a delayed workqueue to handle the above scenario.
The workqueue handler is setup to execute 5 minutes after IMA
initialization is completed.

If a custom IMA policy is loaded before the workqueue handler is
scheduled to execute, the workqueue task is cancelled and any queued keys
are processed for measurement.  But if a custom policy was not loaded then
the queued keys are just freed when the delayed workqueue handler is run.

Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Reported-by: kernel test robot <rong.a.chen@intel.com> # sleeping
function called from invalid context
Reported-by: kbuild test robot <lkp@intel.com> # redefinition of
ima_init_key_queue() function.
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>

Measuring keys requires a custom IMA policy to be loaded.  Keys created
or updated before a custom IMA policy is loaded should be queued and
will be processed after a custom policy is loaded.

This patch defines a workqueue for queuing keys when a custom IMA policy
has not yet been loaded.  An intermediate Kconfig boolean option namely
IMA_QUEUE_EARLY_BOOT_KEYS is used to declare the workqueue functions.

A flag namely ima_process_keys is used to check if the key should be
queued or should be processed immediately.

Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>