integrity: disassociate ima_filter_rule from security_audit_rule

Create real functions for the ima_filter_rule interfaces.
These replace #defines that obscure the reuse of audit
interfaces. The new fuctions are put in security.c because
they use security module registered hooks that we don't
want exported.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Paul Moore <paul@paul-moore.com>

include/linux/security.h

@@ -1917,6 +1917,32 @@ static inline void security_audit_rule_free(void *lsmrule)
 #endif /* CONFIG_SECURITY */
 #endif /* CONFIG_AUDIT */
 
+#ifdef CONFIG_IMA_LSM_RULES
+#ifdef CONFIG_SECURITY
+int ima_filter_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule);
+int ima_filter_rule_match(u32 secid, u32 field, u32 op, void *lsmrule);
+void ima_filter_rule_free(void *lsmrule);
+
+#else
+
+static inline int ima_filter_rule_init(u32 field, u32 op, char *rulestr,
+					   void **lsmrule)
+{
+	return 0;
+}
+
+static inline int ima_filter_rule_match(u32 secid, u32 field, u32 op,
+					    void *lsmrule)
+{
+	return 0;
+}
+
+static inline void ima_filter_rule_free(void *lsmrule)
+{ }
+
+#endif /* CONFIG_SECURITY */
+#endif /* CONFIG_IMA_LSM_RULES */
+
 #ifdef CONFIG_SECURITYFS
 
 extern struct dentry *securityfs_create_file(const char *name, umode_t mode,

security/integrity/ima/ima.h

@@ -418,32 +418,6 @@ static inline void ima_free_modsig(struct modsig *modsig)
 }
 #endif /* CONFIG_IMA_APPRAISE_MODSIG */
 
-/* LSM based policy rules require audit */
-#ifdef CONFIG_IMA_LSM_RULES
-
-#define ima_filter_rule_init security_audit_rule_init
-#define ima_filter_rule_free security_audit_rule_free
-#define ima_filter_rule_match security_audit_rule_match
-
-#else
-
-static inline int ima_filter_rule_init(u32 field, u32 op, char *rulestr,
-				       void **lsmrule)
-{
-	return -EINVAL;
-}
-
-static inline void ima_filter_rule_free(void *lsmrule)
-{
-}
-
-static inline int ima_filter_rule_match(u32 secid, u32 field, u32 op,
-					void *lsmrule)
-{
-	return -EINVAL;
-}
-#endif /* CONFIG_IMA_LSM_RULES */
-
 #ifdef	CONFIG_IMA_READ_POLICY
 #define	POLICY_FILE_FLAGS	(S_IWUSR | S_IRUSR)
 #else

security/security.c

@@ -2563,6 +2563,27 @@ int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule)
 }
 #endif /* CONFIG_AUDIT */
 
+#ifdef CONFIG_IMA_LSM_RULES
+/*
+ * The integrity subsystem uses the same hooks as
+ * the audit subsystem.
+ */
+int ima_filter_rule_init(u32 field, u32 op, char *rulestr, void **lsmrule)
+{
+	return call_int_hook(audit_rule_init, 0, field, op, rulestr, lsmrule);
+}
+
+void ima_filter_rule_free(void *lsmrule)
+{
+	call_void_hook(audit_rule_free, lsmrule);
+}
+
+int ima_filter_rule_match(u32 secid, u32 field, u32 op, void *lsmrule)
+{
+	return call_int_hook(audit_rule_match, 0, secid, field, op, lsmrule);
+}
+#endif /* CONFIG_IMA_LSM_RULES */
+
 #ifdef CONFIG_BPF_SYSCALL
 int security_bpf(int cmd, union bpf_attr *attr, unsigned int size)
 {