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authorLakshmi Ramasubramanian <nramas@linux.microsoft.com>2020-01-22 17:32:06 -0800
committerMimi Zohar <zohar@linux.ibm.com>2020-01-23 07:37:31 -0500
commit5b3014b95272a432b7705142f7081967fc1547f9 (patch)
tree3290001b6ae913d289b6eedb60f59acce50d64bf
parent450d0fd515648dcd90a9940b498f9913ed69566b (diff)
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: 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>
-rw-r--r--security/integrity/ima/ima.h2
-rw-r--r--security/integrity/ima/ima_init.c8
-rw-r--r--security/integrity/ima/ima_queue_keys.c44
3 files changed, 48 insertions, 6 deletions
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 905ed2f7f778..64317d95363e 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -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,
diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
index 5d55ade5f3b9..195cb4079b2b 100644
--- a/security/integrity/ima/ima_init.c
+++ b/security/integrity/ima/ima_init.c
@@ -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;
}
diff --git a/security/integrity/ima/ima_queue_keys.c b/security/integrity/ima/ima_queue_keys.c
index 9b561f2b86db..c87c72299191 100644
--- a/security/integrity/ima/ima_queue_keys.c
+++ b/security/integrity/ima/ima_queue_keys.c
@@ -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) {
@@ -119,13 +150,16 @@ 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) {
- process_buffer_measurement(entry->payload,
- entry->payload_len,
- entry->keyring_name,
- KEY_CHECK, 0,
- entry->keyring_name);
+ if (!timer_expired)
+ process_buffer_measurement(entry->payload,
+ entry->payload_len,
+ entry->keyring_name,
+ KEY_CHECK, 0,
+ entry->keyring_name);
list_del(&entry->list);
ima_free_key_entry(entry);
}