LSM: shrink sizeof LSM specific portion of common_audit_data

Linus found that the gigantic size of the common audit data caused a big
perf hit on something as simple as running stat() in a loop.  This patch
requires LSMs to declare the LSM specific portion separately rather than
doing it in a union.  Thus each LSM can be responsible for shrinking their
portion and don't have to pay a penalty just because other LSMs have a
bigger space requirement.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/lsm_audit.h

@@ -72,61 +72,15 @@ struct common_audit_data {
 	/* this union contains LSM specific data */
 	union {
 #ifdef CONFIG_SECURITY_SMACK
-		/* SMACK data */
-		struct smack_audit_data {
-			const char *function;
-			char *subject;
-			char *object;
-			char *request;
-			int result;
-		} smack_audit_data;
+		struct smack_audit_data *smack_audit_data;
 #endif
 #ifdef CONFIG_SECURITY_SELINUX
-		/* SELinux data */
-		struct {
-			u32 ssid;
-			u32 tsid;
-			u16 tclass;
-			u32 requested;
-			u32 audited;
-			u32 denied;
-			/*
-			 * auditdeny is a bit tricky and unintuitive.  See the
-			 * comments in avc.c for it's meaning and usage.
-			 */
-			u32 auditdeny;
-			struct av_decision *avd;
-			int result;
-		} selinux_audit_data;
+		struct selinux_audit_data *selinux_audit_data;
 #endif
 #ifdef CONFIG_SECURITY_APPARMOR
-		struct {
-			int error;
-			int op;
-			int type;
-			void *profile;
-			const char *name;
-			const char *info;
-			union {
-				void *target;
-				struct {
-					long pos;
-					void *target;
-				} iface;
-				struct {
-					int rlim;
-					unsigned long max;
-				} rlim;
-				struct {
-					const char *target;
-					u32 request;
-					u32 denied;
-					uid_t ouid;
-				} fs;
-			};
-		} apparmor_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 *);

security/apparmor/audit.c

@@ -115,23 +115,23 @@ static void audit_pre(struct audit_buffer *ab, void *ca)
 
 	if (aa_g_audit_header) {
 		audit_log_format(ab, "apparmor=");
-		audit_log_string(ab, aa_audit_type[sa->aad.type]);
+		audit_log_string(ab, aa_audit_type[sa->aad->type]);
 	}
 
-	if (sa->aad.op) {
+	if (sa->aad->op) {
 		audit_log_format(ab, " operation=");
-		audit_log_string(ab, op_table[sa->aad.op]);
+		audit_log_string(ab, op_table[sa->aad->op]);
 	}
 
-	if (sa->aad.info) {
+	if (sa->aad->info) {
 		audit_log_format(ab, " info=");
-		audit_log_string(ab, sa->aad.info);
-		if (sa->aad.error)
-			audit_log_format(ab, " error=%d", sa->aad.error);
+		audit_log_string(ab, sa->aad->info);
+		if (sa->aad->error)
+			audit_log_format(ab, " error=%d", sa->aad->error);
 	}
 
-	if (sa->aad.profile) {
-		struct aa_profile *profile = sa->aad.profile;
+	if (sa->aad->profile) {
+		struct aa_profile *profile = sa->aad->profile;
 		pid_t pid;
 		rcu_read_lock();
 		pid = rcu_dereference(tsk->real_parent)->pid;
@@ -145,9 +145,9 @@ static void audit_pre(struct audit_buffer *ab, void *ca)
 		audit_log_untrustedstring(ab, profile->base.hname);
 	}
 
-	if (sa->aad.name) {
+	if (sa->aad->name) {
 		audit_log_format(ab, " name=");
-		audit_log_untrustedstring(ab, sa->aad.name);
+		audit_log_untrustedstring(ab, sa->aad->name);
 	}
 }
 
@@ -159,7 +159,7 @@ static void audit_pre(struct audit_buffer *ab, void *ca)
 void aa_audit_msg(int type, struct common_audit_data *sa,
 		  void (*cb) (struct audit_buffer *, void *))
 {
-	sa->aad.type = type;
+	sa->aad->type = type;
 	sa->lsm_pre_audit = audit_pre;
 	sa->lsm_post_audit = cb;
 	common_lsm_audit(sa);
@@ -184,7 +184,7 @@ int aa_audit(int type, struct aa_profile *profile, gfp_t gfp,
 	BUG_ON(!profile);
 
 	if (type == AUDIT_APPARMOR_AUTO) {
-		if (likely(!sa->aad.error)) {
+		if (likely(!sa->aad->error)) {
 			if (AUDIT_MODE(profile) != AUDIT_ALL)
 				return 0;
 			type = AUDIT_APPARMOR_AUDIT;
@@ -196,21 +196,21 @@ int aa_audit(int type, struct aa_profile *profile, gfp_t gfp,
 	if (AUDIT_MODE(profile) == AUDIT_QUIET ||
 	    (type == AUDIT_APPARMOR_DENIED &&
 	     AUDIT_MODE(profile) == AUDIT_QUIET))
-		return sa->aad.error;
+		return sa->aad->error;
 
 	if (KILL_MODE(profile) && type == AUDIT_APPARMOR_DENIED)
 		type = AUDIT_APPARMOR_KILL;
 
 	if (!unconfined(profile))
-		sa->aad.profile = profile;
+		sa->aad->profile = profile;
 
 	aa_audit_msg(type, sa, cb);
 
-	if (sa->aad.type == AUDIT_APPARMOR_KILL)
+	if (sa->aad->type == AUDIT_APPARMOR_KILL)
 		(void)send_sig_info(SIGKILL, NULL, sa->tsk ? sa->tsk : current);
 
-	if (sa->aad.type == AUDIT_APPARMOR_ALLOWED)
-		return complain_error(sa->aad.error);
+	if (sa->aad->type == AUDIT_APPARMOR_ALLOWED)
+		return complain_error(sa->aad->error);
 
-	return sa->aad.error;
+	return sa->aad->error;
 }

security/apparmor/capability.c

@@ -64,11 +64,13 @@ static int audit_caps(struct aa_profile *profile, struct task_struct *task,
 	struct audit_cache *ent;
 	int type = AUDIT_APPARMOR_AUTO;
 	struct common_audit_data sa;
+	struct apparmor_audit_data aad = {0,};
 	COMMON_AUDIT_DATA_INIT(&sa, CAP);
+	sa.aad = &aad;
 	sa.tsk = task;
 	sa.u.cap = cap;
-	sa.aad.op = OP_CAPABLE;
-	sa.aad.error = error;
+	sa.aad->op = OP_CAPABLE;
+	sa.aad->error = error;
 
 	if (likely(!error)) {
 		/* test if auditing is being forced */

security/apparmor/file.c

@@ -67,22 +67,22 @@ static void file_audit_cb(struct audit_buffer *ab, void *va)
 	struct common_audit_data *sa = va;
 	uid_t fsuid = current_fsuid();
 
-	if (sa->aad.fs.request & AA_AUDIT_FILE_MASK) {
+	if (sa->aad->fs.request & AA_AUDIT_FILE_MASK) {
 		audit_log_format(ab, " requested_mask=");
-		audit_file_mask(ab, sa->aad.fs.request);
+		audit_file_mask(ab, sa->aad->fs.request);
 	}
-	if (sa->aad.fs.denied & AA_AUDIT_FILE_MASK) {
+	if (sa->aad->fs.denied & AA_AUDIT_FILE_MASK) {
 		audit_log_format(ab, " denied_mask=");
-		audit_file_mask(ab, sa->aad.fs.denied);
+		audit_file_mask(ab, sa->aad->fs.denied);
 	}
-	if (sa->aad.fs.request & AA_AUDIT_FILE_MASK) {
+	if (sa->aad->fs.request & AA_AUDIT_FILE_MASK) {
 		audit_log_format(ab, " fsuid=%d", fsuid);
-		audit_log_format(ab, " ouid=%d", sa->aad.fs.ouid);
+		audit_log_format(ab, " ouid=%d", sa->aad->fs.ouid);
 	}
 
-	if (sa->aad.fs.target) {
+	if (sa->aad->fs.target) {
 		audit_log_format(ab, " target=");
-		audit_log_untrustedstring(ab, sa->aad.fs.target);
+		audit_log_untrustedstring(ab, sa->aad->fs.target);
 	}
 }
 
@@ -107,45 +107,47 @@ int aa_audit_file(struct aa_profile *profile, struct file_perms *perms,
 {
 	int type = AUDIT_APPARMOR_AUTO;
 	struct common_audit_data sa;
+	struct apparmor_audit_data aad = {0,};
 	COMMON_AUDIT_DATA_INIT(&sa, NONE);
-	sa.aad.op = op,
-	sa.aad.fs.request = request;
-	sa.aad.name = name;
-	sa.aad.fs.target = target;
-	sa.aad.fs.ouid = ouid;
-	sa.aad.info = info;
-	sa.aad.error = error;
-
-	if (likely(!sa.aad.error)) {
+	sa.aad = &aad;
+	aad.op = op,
+	aad.fs.request = request;
+	aad.name = name;
+	aad.fs.target = target;
+	aad.fs.ouid = ouid;
+	aad.info = info;
+	aad.error = error;
+
+	if (likely(!sa.aad->error)) {
 		u32 mask = perms->audit;
 
 		if (unlikely(AUDIT_MODE(profile) == AUDIT_ALL))
 			mask = 0xffff;
 
 		/* mask off perms that are not being force audited */
-		sa.aad.fs.request &= mask;
+		sa.aad->fs.request &= mask;
 
-		if (likely(!sa.aad.fs.request))
+		if (likely(!sa.aad->fs.request))
 			return 0;
 		type = AUDIT_APPARMOR_AUDIT;
 	} else {
 		/* only report permissions that were denied */
-		sa.aad.fs.request = sa.aad.fs.request & ~perms->allow;
+		sa.aad->fs.request = sa.aad->fs.request & ~perms->allow;
 
-		if (sa.aad.fs.request & perms->kill)
+		if (sa.aad->fs.request & perms->kill)
 			type = AUDIT_APPARMOR_KILL;
 
 		/* quiet known rejects, assumes quiet and kill do not overlap */
-		if ((sa.aad.fs.request & perms->quiet) &&
+		if ((sa.aad->fs.request & perms->quiet) &&
 		    AUDIT_MODE(profile) != AUDIT_NOQUIET &&
 		    AUDIT_MODE(profile) != AUDIT_ALL)
-			sa.aad.fs.request &= ~perms->quiet;
+			sa.aad->fs.request &= ~perms->quiet;
 
-		if (!sa.aad.fs.request)
-			return COMPLAIN_MODE(profile) ? 0 : sa.aad.error;
+		if (!sa.aad->fs.request)
+			return COMPLAIN_MODE(profile) ? 0 : sa.aad->error;
 	}
 
-	sa.aad.fs.denied = sa.aad.fs.request & ~perms->allow;
+	sa.aad->fs.denied = sa.aad->fs.request & ~perms->allow;
 	return aa_audit(type, profile, gfp, &sa, file_audit_cb);
 }
 

security/apparmor/include/audit.h

@@ -103,7 +103,33 @@ enum aa_ops {
 };
 
 
-/* define a short hand for apparmor_audit_data portion of common_audit_data */
+struct apparmor_audit_data {
+	int error;
+	int op;
+	int type;
+	void *profile;
+	const char *name;
+	const char *info;
+	union {
+		void *target;
+		struct {
+			long pos;
+			void *target;
+		} iface;
+		struct {
+			int rlim;
+			unsigned long max;
+		} rlim;
+		struct {
+			const char *target;
+			u32 request;
+			u32 denied;
+			uid_t ouid;
+		} fs;
+	};
+};
+
+/* define a short hand for apparmor_audit_data structure */
 #define aad apparmor_audit_data
 
 void aa_audit_msg(int type, struct common_audit_data *sa,

security/apparmor/ipc.c

@@ -26,7 +26,7 @@ static void audit_cb(struct audit_buffer *ab, void *va)
 {
 	struct common_audit_data *sa = va;
 	audit_log_format(ab, " target=");
-	audit_log_untrustedstring(ab, sa->aad.target);
+	audit_log_untrustedstring(ab, sa->aad->target);
 }
 
 /**
@@ -41,10 +41,12 @@ static int aa_audit_ptrace(struct aa_profile *profile,
 			   struct aa_profile *target, int error)
 {
 	struct common_audit_data sa;
+	struct apparmor_audit_data aad = {0,};
 	COMMON_AUDIT_DATA_INIT(&sa, NONE);
-	sa.aad.op = OP_PTRACE;
-	sa.aad.target = target;
-	sa.aad.error = error;
+	sa.aad = &aad;
+	aad.op = OP_PTRACE;
+	aad.target = target;
+	aad.error = error;
 
 	return aa_audit(AUDIT_APPARMOR_AUTO, profile, GFP_ATOMIC, &sa,
 			audit_cb);

security/apparmor/lib.c

@@ -65,8 +65,10 @@ void aa_info_message(const char *str)
 {
 	if (audit_enabled) {
 		struct common_audit_data sa;
+		struct apparmor_audit_data aad = {0,};
 		COMMON_AUDIT_DATA_INIT(&sa, NONE);
-		sa.aad.info = str;
+		sa.aad = &aad;
+		aad.info = str;
 		aa_audit_msg(AUDIT_APPARMOR_STATUS, &sa, NULL);
 	}
 	printk(KERN_INFO "AppArmor: %s\n", str);

security/apparmor/lsm.c

@@ -588,10 +588,12 @@ static int apparmor_setprocattr(struct task_struct *task, char *name,
 			error = aa_setprocattr_permipc(args);
 		} else {
 			struct common_audit_data sa;
+			struct apparmor_audit_data aad = {0,};
 			COMMON_AUDIT_DATA_INIT(&sa, NONE);
-			sa.aad.op = OP_SETPROCATTR;
-			sa.aad.info = name;
-			sa.aad.error = -EINVAL;
+			sa.aad = &aad;
+			aad.op = OP_SETPROCATTR;
+			aad.info = name;
+			aad.error = -EINVAL;
 			return aa_audit(AUDIT_APPARMOR_DENIED,
 					__aa_current_profile(), GFP_KERNEL,
 					&sa, NULL);

security/apparmor/policy.c

@@ -964,11 +964,13 @@ static int audit_policy(int op, gfp_t gfp, const char *name, const char *info,
 			int error)
 {
 	struct common_audit_data sa;
+	struct apparmor_audit_data aad = {0,};
 	COMMON_AUDIT_DATA_INIT(&sa, NONE);
-	sa.aad.op = op;
-	sa.aad.name = name;
-	sa.aad.info = info;
-	sa.aad.error = error;
+	sa.aad = &aad;
+	aad.op = op;
+	aad.name = name;
+	aad.info = info;
+	aad.error = error;
 
 	return aa_audit(AUDIT_APPARMOR_STATUS, __aa_current_profile(), gfp,
 			&sa, NULL);

security/apparmor/policy_unpack.c

@@ -70,13 +70,13 @@ struct aa_ext {
 static void audit_cb(struct audit_buffer *ab, void *va)
 {
 	struct common_audit_data *sa = va;
-	if (sa->aad.iface.target) {
-		struct aa_profile *name = sa->aad.iface.target;
+	if (sa->aad->iface.target) {
+		struct aa_profile *name = sa->aad->iface.target;
 		audit_log_format(ab, " name=");
 		audit_log_untrustedstring(ab, name->base.hname);
 	}
-	if (sa->aad.iface.pos)
-		audit_log_format(ab, " offset=%ld", sa->aad.iface.pos);
+	if (sa->aad->iface.pos)
+		audit_log_format(ab, " offset=%ld", sa->aad->iface.pos);
 }
 
 /**
@@ -94,13 +94,15 @@ static int audit_iface(struct aa_profile *new, const char *name,
 {
 	struct aa_profile *profile = __aa_current_profile();
 	struct common_audit_data sa;
+	struct apparmor_audit_data aad = {0,};
 	COMMON_AUDIT_DATA_INIT(&sa, NONE);
+	sa.aad = &aad;
 	if (e)
-		sa.aad.iface.pos = e->pos - e->start;
-	sa.aad.iface.target = new;
-	sa.aad.name = name;
-	sa.aad.info = info;
-	sa.aad.error = error;
+		aad.iface.pos = e->pos - e->start;
+	aad.iface.target = new;
+	aad.name = name;
+	aad.info = info;
+	aad.error = error;
 
 	return aa_audit(AUDIT_APPARMOR_STATUS, profile, GFP_KERNEL, &sa,
 			audit_cb);

security/apparmor/resource.c

@@ -34,7 +34,7 @@ static void audit_cb(struct audit_buffer *ab, void *va)
 	struct common_audit_data *sa = va;
 
 	audit_log_format(ab, " rlimit=%s value=%lu",
-			 rlim_names[sa->aad.rlim.rlim], sa->aad.rlim.max);
+			 rlim_names[sa->aad->rlim.rlim], sa->aad->rlim.max);
 }
 
 /**
@@ -50,12 +50,14 @@ static int audit_resource(struct aa_profile *profile, unsigned int resource,
 			  unsigned long value, int error)
 {
 	struct common_audit_data sa;
+	struct apparmor_audit_data aad = {0,};
 
 	COMMON_AUDIT_DATA_INIT(&sa, NONE);
-	sa.aad.op = OP_SETRLIMIT,
-	sa.aad.rlim.rlim = resource;
-	sa.aad.rlim.max = value;
-	sa.aad.error = error;
+	sa.aad = &aad;
+	aad.op = OP_SETRLIMIT,
+	aad.rlim.rlim = resource;
+	aad.rlim.max = value;
+	aad.error = error;
 	return aa_audit(AUDIT_APPARMOR_AUTO, profile, GFP_KERNEL, &sa,
 			audit_cb);
 }

security/selinux/avc.c

@@ -436,9 +436,9 @@ static void avc_audit_pre_callback(struct audit_buffer *ab, void *a)
 {
 	struct common_audit_data *ad = a;
 	audit_log_format(ab, "avc:  %s ",
-			 ad->selinux_audit_data.denied ? "denied" : "granted");
-	avc_dump_av(ab, ad->selinux_audit_data.tclass,
-			ad->selinux_audit_data.audited);
+			 ad->selinux_audit_data->denied ? "denied" : "granted");
+	avc_dump_av(ab, ad->selinux_audit_data->tclass,
+			ad->selinux_audit_data->audited);
 	audit_log_format(ab, " for ");
 }
 
@@ -452,9 +452,9 @@ static void avc_audit_post_callback(struct audit_buffer *ab, void *a)
 {
 	struct common_audit_data *ad = a;
 	audit_log_format(ab, " ");
-	avc_dump_query(ab, ad->selinux_audit_data.ssid,
-			   ad->selinux_audit_data.tsid,
-			   ad->selinux_audit_data.tclass);
+	avc_dump_query(ab, ad->selinux_audit_data->ssid,
+			   ad->selinux_audit_data->tsid,
+			   ad->selinux_audit_data->tclass);
 }
 
 /* This is the slow part of avc audit with big stack footprint */
@@ -464,10 +464,12 @@ static noinline int slow_avc_audit(u32 ssid, u32 tsid, u16 tclass,
 		unsigned flags)
 {
 	struct common_audit_data stack_data;
+	struct selinux_audit_data sad = {0,};
 
 	if (!a) {
 		a = &stack_data;
 		COMMON_AUDIT_DATA_INIT(a, NONE);
+		a->selinux_audit_data = &sad;
 	}
 
 	/*
@@ -481,12 +483,12 @@ static noinline int slow_avc_audit(u32 ssid, u32 tsid, u16 tclass,
 	    (flags & MAY_NOT_BLOCK))
 		return -ECHILD;
 
-	a->selinux_audit_data.tclass = tclass;
-	a->selinux_audit_data.requested = requested;
-	a->selinux_audit_data.ssid = ssid;
-	a->selinux_audit_data.tsid = tsid;
-	a->selinux_audit_data.audited = audited;
-	a->selinux_audit_data.denied = denied;
+	a->selinux_audit_data->tclass = tclass;
+	a->selinux_audit_data->requested = requested;
+	a->selinux_audit_data->ssid = ssid;
+	a->selinux_audit_data->tsid = tsid;
+	a->selinux_audit_data->audited = audited;
+	a->selinux_audit_data->denied = denied;
 	a->lsm_pre_audit = avc_audit_pre_callback;
 	a->lsm_post_audit = avc_audit_post_callback;
 	common_lsm_audit(a);
@@ -523,7 +525,7 @@ inline int avc_audit(u32 ssid, u32 tsid,
 	if (unlikely(denied)) {
 		audited = denied & avd->auditdeny;
 		/*
-		 * a->selinux_audit_data.auditdeny is TRICKY!  Setting a bit in
+		 * a->selinux_audit_data->auditdeny is TRICKY!  Setting a bit in
 		 * this field means that ANY denials should NOT be audited if
 		 * the policy contains an explicit dontaudit rule for that
 		 * permission.  Take notice that this is unrelated to the
@@ -532,15 +534,15 @@ inline int avc_audit(u32 ssid, u32 tsid,
 		 *
 		 * denied == READ
 		 * avd.auditdeny & ACCESS == 0 (not set means explicit rule)
-		 * selinux_audit_data.auditdeny & ACCESS == 1
+		 * selinux_audit_data->auditdeny & ACCESS == 1
 		 *
 		 * We will NOT audit the denial even though the denied
 		 * permission was READ and the auditdeny checks were for
 		 * ACCESS
 		 */
 		if (a &&
-		    a->selinux_audit_data.auditdeny &&
-		    !(a->selinux_audit_data.auditdeny & avd->auditdeny))
+		    a->selinux_audit_data->auditdeny &&
+		    !(a->selinux_audit_data->auditdeny & avd->auditdeny))
 			audited = 0;
 	} else if (result)
 		audited = denied = requested;

security/selinux/include/avc.h

@@ -46,6 +46,22 @@ struct avc_cache_stats {
 	unsigned int frees;
 };
 
+struct selinux_audit_data {
+	u32 ssid;
+	u32 tsid;
+	u16 tclass;
+	u32 requested;
+	u32 audited;
+	u32 denied;
+	/*
+	 * auditdeny is a bit tricky and unintuitive.  See the
+	 * comments in avc.c for it's meaning and usage.
+	 */
+	u32 auditdeny;
+	struct av_decision *avd;
+	int result;
+};
+
 /*
  * AVC operations
  */

security/smack/smack.h

@@ -185,6 +185,15 @@ struct smack_known {
  */
 #define SMK_NUM_ACCESS_TYPE 5
 
+/* SMACK data */
+struct smack_audit_data {
+	const char *function;
+	char *subject;
+	char *object;
+	char *request;
+	int result;
+};
+
 /*
  * Smack audit data; is empty if CONFIG_AUDIT not set
  * to save some stack
@@ -192,6 +201,7 @@ struct smack_known {
 struct smk_audit_info {
 #ifdef CONFIG_AUDIT
 	struct common_audit_data a;
+	struct smack_audit_data sad;
 #endif
 };
 /*
@@ -311,7 +321,8 @@ static inline void smk_ad_init(struct smk_audit_info *a, const char *func,
 {
 	memset(a, 0, sizeof(*a));
 	a->a.type = type;
-	a->a.smack_audit_data.function = func;
+	a->a.smack_audit_data = &a->sad;
+	a->a.smack_audit_data->function = func;
 }
 
 static inline void smk_ad_setfield_u_tsk(struct smk_audit_info *a,

security/smack/smack_access.c

@@ -275,9 +275,9 @@ static inline void smack_str_from_perm(char *string, int access)
 static void smack_log_callback(struct audit_buffer *ab, void *a)
 {
 	struct common_audit_data *ad = a;
-	struct smack_audit_data *sad = &ad->smack_audit_data;
+	struct smack_audit_data *sad = ad->smack_audit_data;
 	audit_log_format(ab, "lsm=SMACK fn=%s action=%s",
-			 ad->smack_audit_data.function,
+			 ad->smack_audit_data->function,
 			 sad->result ? "denied" : "granted");
 	audit_log_format(ab, " subject=");
 	audit_log_untrustedstring(ab, sad->subject);
@@ -310,11 +310,12 @@ void smack_log(char *subject_label, char *object_label, int request,
 	if (result == 0 && (log_policy & SMACK_AUDIT_ACCEPT) == 0)
 		return;
 
-	if (a->smack_audit_data.function == NULL)
-		a->smack_audit_data.function = "unknown";
+	sad = a->smack_audit_data;
+
+	if (sad->function == NULL)
+		sad->function = "unknown";
 
 	/* end preparing the audit data */
-	sad = &a->smack_audit_data;
 	smack_str_from_perm(request_buffer, request);
 	sad->subject = subject_label;
 	sad->object  = object_label;