Replace the secid value stored in struct audit_context with a struct
lsm_prop. Change the code that uses this value to accommodate the
change. security_audit_rule_match() expects a lsm_prop, so existing
scaffolding can be removed. A call to security_secid_to_secctx()
is changed to security_lsmprop_to_secctx().  The call to
security_ipc_getsecid() is scaffolded.

A new function lsmprop_is_set() is introduced to identify whether
an lsm_prop contains a non-zero value.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/security.h | 24 ++++++++++++++++++++++++
 kernel/audit.h           |  3 ++-
 kernel/auditsc.c         | 19 ++++++++-----------
 3 files changed, 34 insertions(+), 12 deletions(-)

diff --git a/include/linux/security.h b/include/linux/security.h
index f1c68e38b15d..5652baa4ca3c 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h

@@ -291,6 +291,19 @@ static inline const char *kernel_load_data_id_str(enum kernel_load_data_id id)
 
 #ifdef CONFIG_SECURITY
 
+/**
+ * lsmprop_is_set - report if there is a value in the lsm_prop
+ * @prop: Pointer to the exported LSM data
+ *
+ * Returns true if there is a value set, false otherwise
+ */
+static inline bool lsm_prop_is_set(struct lsm_prop *prop)
+{
+	const struct lsm_prop empty = {};
+
+	return !!memcmp(prop, &empty, sizeof(*prop));
+}
+
 int call_blocking_lsm_notifier(enum lsm_event event, void *data);
 int register_blocking_lsm_notifier(struct notifier_block *nb);
 int unregister_blocking_lsm_notifier(struct notifier_block *nb);

@@ -552,6 +565,17 @@ int security_bdev_setintegrity(struct block_device *bdev,
 			       size_t size);
 #else /* CONFIG_SECURITY */
 
+/**
+ * lsmprop_is_set - report if there is a value in the lsm_prop
+ * @prop: Pointer to the exported LSM data
+ *
+ * Returns true if there is a value set, false otherwise
+ */
+static inline bool lsm_prop_is_set(struct lsm_prop *prop)
+{
+	return false;
+}