IMA: Define workqueue for early boot key measurements

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>

1 files changed, 22 insertions, 0 deletions

diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index f06238e41a7c..905ed2f7f778 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -205,6 +205,28 @@ extern const char *const func_tokens[];
 
 struct modsig;
 
+#ifdef CONFIG_IMA_QUEUE_EARLY_BOOT_KEYS
+/*
+ * To track keys that need to be measured.
+ */
+struct ima_key_entry {
+	struct list_head list;
+	void *payload;
+	size_t payload_len;
+	char *keyring_name;
+};
+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 bool ima_should_queue_key(void) { return false; }
+static inline bool ima_queue_key(struct key *keyring,
+				 const void *payload,
+				 size_t payload_len) { return false; }
+static inline void ima_process_queued_keys(void) {}
+#endif /* CONFIG_IMA_QUEUE_EARLY_BOOT_KEYS */
+
 /* LIM API function definitions */
 int ima_get_action(struct inode *inode, const struct cred *cred, u32 secid,
 		   int mask, enum ima_hooks func, int *pcr,