lsm_audit: don't specify the audit pre/post callbacks in 'struct common_audit_data'

It just bloats the audit data structure for no good reason, since the
only time those fields are filled are just before calling the
common_lsm_audit() function, which is also the only user of those
fields.

So just make them be the arguments to common_lsm_audit(), rather than
bloating that structure that is passed around everywhere, and is
initialized in hot paths.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/lsm_audit.h

@@ -82,9 +82,6 @@ struct common_audit_data {
 		struct apparmor_audit_data *apparmor_audit_data;
 #endif
 	}; /* per LSM data pointer union */
-	/* these callback will be implemented by a specific LSM */
-	void (*lsm_pre_audit)(struct audit_buffer *, void *);
-	void (*lsm_post_audit)(struct audit_buffer *, void *);
 };
 
 #define v4info fam.v4
@@ -101,6 +98,8 @@ int ipv6_skb_to_auditdata(struct sk_buff *skb,
 	{ memset((_d), 0, sizeof(struct common_audit_data)); \
 	 (_d)->type = LSM_AUDIT_DATA_##_t; }
 
-void common_lsm_audit(struct common_audit_data *a);
+void common_lsm_audit(struct common_audit_data *a,
+	void (*pre_audit)(struct audit_buffer *, void *),
+	void (*post_audit)(struct audit_buffer *, void *));
 
 #endif

security/apparmor/audit.c

@@ -160,9 +160,7 @@ void aa_audit_msg(int type, struct common_audit_data *sa,
 		  void (*cb) (struct audit_buffer *, void *))
 {
 	sa->aad->type = type;
-	sa->lsm_pre_audit = audit_pre;
-	sa->lsm_post_audit = cb;
-	common_lsm_audit(sa);
+	common_lsm_audit(sa, audit_pre, cb);
 }
 
 /**

security/lsm_audit.c

@@ -378,11 +378,15 @@ static void dump_common_audit_data(struct audit_buffer *ab,
 /**
  * common_lsm_audit - generic LSM auditing function
  * @a:  auxiliary audit data
+ * @pre_audit: lsm-specific pre-audit callback
+ * @post_audit: lsm-specific post-audit callback
  *
  * setup the audit buffer for common security information
  * uses callback to print LSM specific information
  */
-void common_lsm_audit(struct common_audit_data *a)
+void common_lsm_audit(struct common_audit_data *a,
+	void (*pre_audit)(struct audit_buffer *, void *),
+	void (*post_audit)(struct audit_buffer *, void *))
 {
 	struct audit_buffer *ab;
 
@@ -394,13 +398,13 @@ void common_lsm_audit(struct common_audit_data *a)
 	if (ab == NULL)
 		return;
 
-	if (a->lsm_pre_audit)
-		a->lsm_pre_audit(ab, a);
+	if (pre_audit)
+		pre_audit(ab, a);
 
 	dump_common_audit_data(ab, a);
 
-	if (a->lsm_post_audit)
-		a->lsm_post_audit(ab, a);
+	if (post_audit)
+		post_audit(ab, a);
 
 	audit_log_end(ab);
 }

security/selinux/avc.c

@@ -492,9 +492,7 @@ static noinline int slow_avc_audit(u32 ssid, u32 tsid, u16 tclass,
 	slad.denied = denied;
 
 	a->selinux_audit_data->slad = &slad;
-	a->lsm_pre_audit = avc_audit_pre_callback;
-	a->lsm_post_audit = avc_audit_post_callback;
-	common_lsm_audit(a);
+	common_lsm_audit(a, avc_audit_pre_callback, avc_audit_post_callback);
 	return 0;
 }
 

security/smack/smack_access.c

@@ -321,9 +321,8 @@ void smack_log(char *subject_label, char *object_label, int request,
 	sad->object  = object_label;
 	sad->request = request_buffer;
 	sad->result  = result;
-	a->lsm_pre_audit = smack_log_callback;
 
-	common_lsm_audit(a);
+	common_lsm_audit(a, smack_log_callback, NULL);
 }
 #else /* #ifdef CONFIG_AUDIT */
 void smack_log(char *subject_label, char *object_label, int request,