Commit 5b3014b9 authored by Lakshmi Ramasubramanian's avatar Lakshmi Ramasubramanian Committed by Mimi Zohar
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IMA: Defined delayed workqueue to free the queued keys 



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: default avatarLakshmi 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: default avatarMimi Zohar <zohar@linux.ibm.com>
parent 450d0fd5

security/integrity/ima/ima.h

+2 −0
Original line number Diff line number Diff line
@@ -215,11 +215,13 @@ struct ima_key_entry { 
	size_t payload_len;

	char *keyring_name;

};

void ima_init_key_queue(void);

bool ima_should_queue_key(void);

bool ima_queue_key(struct key *keyring, const void *payload,

		   size_t payload_len);

void ima_process_queued_keys(void);

#else

static inline void ima_init_key_queue(void) {}

static inline bool ima_should_queue_key(void) { return false; }

static inline bool ima_queue_key(struct key *keyring,

				 const void *payload,

security/integrity/ima/ima_init.c

+7 −1
Original line number Diff line number Diff line
@@ -131,5 +131,11 @@ int __init ima_init(void) 


	ima_init_policy();



	return ima_fs_init();

	rc = ima_fs_init();

	if (rc != 0)

		return rc;



	ima_init_key_queue();



	return rc;

}

security/integrity/ima/ima_queue_keys.c

+39 −5
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt



#include <linux/workqueue.h>

#include <keys/asymmetric-type.h>

#include "ima.h"
@@ -25,6 +26,36 @@ static bool ima_process_keys; 
static DEFINE_MUTEX(ima_keys_lock);

static LIST_HEAD(ima_keys);



/*

 * If custom IMA policy is not loaded then keys queued up

 * for measurement should be freed. This worker is used

 * for handling this scenario.

 */

static long ima_key_queue_timeout = 300000; /* 5 Minutes */

static void ima_keys_handler(struct work_struct *work);

static DECLARE_DELAYED_WORK(ima_keys_delayed_work, ima_keys_handler);

static bool timer_expired;



/*

 * This worker function frees keys that may still be

 * queued up in case custom IMA policy was not loaded.

 */

static void ima_keys_handler(struct work_struct *work)

{

	timer_expired = true;

	ima_process_queued_keys();

}



/*

 * This function sets up a worker to free queued keys in case

 * custom IMA policy was never loaded.

 */

void ima_init_key_queue(void)

{

	schedule_delayed_work(&ima_keys_delayed_work,

			      msecs_to_jiffies(ima_key_queue_timeout));

}



static void ima_free_key_entry(struct ima_key_entry *entry)

{

	if (entry) {
@@ -119,8 +150,11 @@ void ima_process_queued_keys(void) 
	if (!process)

		return;



	if (!timer_expired)

		cancel_delayed_work_sync(&ima_keys_delayed_work);



	list_for_each_entry_safe(entry, tmp, &ima_keys, list) {

		if (!timer_expired)

			process_buffer_measurement(entry->payload,

						   entry->payload_len,

						   entry->keyring_name,

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