From 5b3014b95272a432b7705142f7081967fc1547f9 Mon Sep 17 00:00:00 2001 From: Lakshmi Ramasubramanian Date: Wed, 22 Jan 2020 17:32:06 -0800 Subject: 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 Reported-by: kernel test robot # sleeping function called from invalid context Reported-by: kbuild test robot # redefinition of ima_init_key_queue() function. Signed-off-by: Mimi Zohar --- security/integrity/ima/ima.h | 2 ++ security/integrity/ima/ima_init.c | 8 +++++- security/integrity/ima/ima_queue_keys.c | 44 +++++++++++++++++++++++++++++---- 3 files changed, 48 insertions(+), 6 deletions(-) (limited to 'security/integrity') 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 #include #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); } -- cgit v1.2.3