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 timer to handle the above scenario. The timer
is setup to expire 5 minutes after IMA initialization is completed.
If a custom IMA policy is loaded before the timer expires, the timer
is removed and any queued keys are processed for measurement.
But if a custom policy was not loaded, on timer expiration
queued keys are just freed.
Signed-off-by: Lakshmi Ramasubramanian <[email protected]>
---
security/integrity/ima/ima.h | 2 +
security/integrity/ima/ima_asymmetric_keys.c | 42 ++++++++++++++++++--
security/integrity/ima/ima_init.c | 8 +++-
3 files changed, 48 insertions(+), 4 deletions(-)
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index 97f8a4078483..c483215a9ee5 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -216,8 +216,10 @@ struct ima_key_entry {
char *keyring_name;
};
void ima_process_queued_keys(void);
+void ima_init_key_queue(void);
#else
static inline void ima_process_queued_keys(void) {}
+static inline void ima_init_key_queue(void) {}
#endif /* CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE */
/* LIM API function definitions */
diff --git a/security/integrity/ima/ima_asymmetric_keys.c b/security/integrity/ima/ima_asymmetric_keys.c
index 4124f10ff0c2..9ea2233c911a 100644
--- a/security/integrity/ima/ima_asymmetric_keys.c
+++ b/security/integrity/ima/ima_asymmetric_keys.c
@@ -11,6 +11,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/timer.h>
#include <keys/asymmetric-type.h>
#include "ima.h"
@@ -26,6 +27,36 @@ static bool ima_process_keys;
static DEFINE_MUTEX(ima_keys_mutex);
static LIST_HEAD(ima_keys);
+/*
+ * If custom IMA policy is not loaded then keys queued up
+ * for measurement should be freed. This timer is used
+ * for handling this scenario.
+ */
+static long ima_key_queue_timeout = 300000; /* 5 Minutes */
+static struct timer_list ima_key_queue_timer;
+static bool timer_expired;
+
+/*
+ * This timer callback function frees keys that may still be
+ * queued up in case custom IMA policy was not loaded.
+ */
+static void ima_timer_handler(struct timer_list *timer)
+{
+ timer_expired = true;
+ ima_process_queued_keys();
+}
+
+/*
+ * This function sets up a timer to free queued keys in case
+ * custom IMA policy was never loaded.
+ */
+void ima_init_key_queue(void)
+{
+ timer_setup(&ima_key_queue_timer, ima_timer_handler, 0);
+ mod_timer(&ima_key_queue_timer,
+ jiffies + msecs_to_jiffies(ima_key_queue_timeout));
+}
+
static void ima_free_key_entry(struct ima_key_entry *entry)
{
if (entry) {
@@ -120,10 +151,15 @@ void ima_process_queued_keys(void)
if (!process)
return;
+ del_timer(&ima_key_queue_timer);
+
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);
}
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;
}
--
2.17.1
On Tue, 2019-12-24 at 10:01 -0800, Lakshmi Ramasubramanian wrote:
> 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 timer to handle the above scenario. The timer
> is setup to expire 5 minutes after IMA initialization is completed.
>
> If a custom IMA policy is loaded before the timer expires, the timer
> is removed and any queued keys are processed for measurement.
> But if a custom policy was not loaded, on timer expiration
> queued keys are just freed.
>
> Signed-off-by: Lakshmi Ramasubramanian <[email protected]>
Thanks. This patch is now queued in next-integrity-testing.
Mimi
> ---
> security/integrity/ima/ima.h | 2 +
> security/integrity/ima/ima_asymmetric_keys.c | 42 ++++++++++++++++++--
> security/integrity/ima/ima_init.c | 8 +++-
> 3 files changed, 48 insertions(+), 4 deletions(-)
>
> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> index 97f8a4078483..c483215a9ee5 100644
> --- a/security/integrity/ima/ima.h
> +++ b/security/integrity/ima/ima.h
> @@ -216,8 +216,10 @@ struct ima_key_entry {
> char *keyring_name;
> };
> void ima_process_queued_keys(void);
> +void ima_init_key_queue(void);
> #else
> static inline void ima_process_queued_keys(void) {}
> +static inline void ima_init_key_queue(void) {}
> #endif /* CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE */
>
> /* LIM API function definitions */
> diff --git a/security/integrity/ima/ima_asymmetric_keys.c b/security/integrity/ima/ima_asymmetric_keys.c
> index 4124f10ff0c2..9ea2233c911a 100644
> --- a/security/integrity/ima/ima_asymmetric_keys.c
> +++ b/security/integrity/ima/ima_asymmetric_keys.c
> @@ -11,6 +11,7 @@
>
> #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>
> +#include <linux/timer.h>
> #include <keys/asymmetric-type.h>
> #include "ima.h"
>
> @@ -26,6 +27,36 @@ static bool ima_process_keys;
> static DEFINE_MUTEX(ima_keys_mutex);
> static LIST_HEAD(ima_keys);
>
> +/*
> + * If custom IMA policy is not loaded then keys queued up
> + * for measurement should be freed. This timer is used
> + * for handling this scenario.
> + */
> +static long ima_key_queue_timeout = 300000; /* 5 Minutes */
> +static struct timer_list ima_key_queue_timer;
> +static bool timer_expired;
> +
> +/*
> + * This timer callback function frees keys that may still be
> + * queued up in case custom IMA policy was not loaded.
> + */
> +static void ima_timer_handler(struct timer_list *timer)
> +{
> + timer_expired = true;
> + ima_process_queued_keys();
> +}
> +
> +/*
> + * This function sets up a timer to free queued keys in case
> + * custom IMA policy was never loaded.
> + */
> +void ima_init_key_queue(void)
> +{
> + timer_setup(&ima_key_queue_timer, ima_timer_handler, 0);
> + mod_timer(&ima_key_queue_timer,
> + jiffies + msecs_to_jiffies(ima_key_queue_timeout));
> +}
> +
> static void ima_free_key_entry(struct ima_key_entry *entry)
> {
> if (entry) {
> @@ -120,10 +151,15 @@ void ima_process_queued_keys(void)
> if (!process)
> return;
>
> + del_timer(&ima_key_queue_timer);
> +
> 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);
> }
> 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;
> }