[RFC] integrity: disassociate ima_filter_rule from security_audit_rule

Commit Message

Casey Schaufler Nov. 4, 2021, 9:38 p.m. UTC

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

Signed-off-by: Casey Schaufler <[e-mail]>
---
  include/linux/security.h     | 26 ++++++++++++++++++++++++++
  security/integrity/ima/ima.h | 26 --------------------------
  security/security.c          | 21 +++++++++++++++++++++
  3 files changed, 47 insertions(+), 26 deletions(-)

Comments

Mimi Zohar Nov. 4, 2021, 9:46 p.m. UTC | #1

Hi Casey,

On Thu, 2021-11-04 at 14:38 -0700, Casey Schaufler wrote:
> Create real functions for the ima_filter_rule interfaces.
> These replace #defines that obscure the reuse of audit
> interfaces. The new functions are put in security.c because
> they use security module registered hooks that we don't
> want exported.
> 
> Signed-off-by: Casey Schaufler <[e-mail]>

It looks fine to me.

Mimi

Patch

diff --git a/include/linux/security.h b/include/linux/security.h
index 7e0ba63b5dde..f98d047b8d0a 100644
--- a/include/linux/security.h
+++ b/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,
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index be965a8715e4..1b5d70ac2dc9 100644
--- a/security/integrity/ima/ima.h
+++ b/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
diff --git a/security/security.c b/security/security.c
index 95e30fadba78..19ffb1bceb3b 100644
--- a/security/security.c
+++ b/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)
  {