[PATCH v39 22/42] Audit: Create audit_stamp structure

[Casey Schaufler <casey@schaufler-ca.com>]

Replace the timestamp and serial number pair used in audit records
with a structure containing the two elements.

Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Acked-by: Paul Moore <paul@paul-moore.com>
---
 kernel/audit.c   | 17 +++++++++--------
 kernel/audit.h   | 13 +++++++++----
 kernel/auditsc.c | 22 +++++++++-------------
 3 files changed, 27 insertions(+), 25 deletions(-)

diff --git a/kernel/audit.c b/kernel/audit.c
index edefb370a72e..5291f65a01c8 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1820,11 +1820,11 @@ unsigned int audit_serial(void)
 }
 
 static inline void audit_get_stamp(struct audit_context *ctx,
-				   struct timespec64 *t, unsigned int *serial)
+				   struct audit_stamp *stamp)
 {
-	if (!ctx || !auditsc_get_stamp(ctx, t, serial)) {
-		ktime_get_coarse_real_ts64(t);
-		*serial = audit_serial();
+	if (!ctx || !auditsc_get_stamp(ctx, stamp)) {
+		ktime_get_coarse_real_ts64(&stamp->ctime);
+		stamp->serial = audit_serial();
 	}
 }
 
@@ -1847,8 +1847,7 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
 				     int type)
 {
 	struct audit_buffer *ab;
-	struct timespec64 t;
-	unsigned int serial;
+	struct audit_stamp stamp;
 
 	if (audit_initialized != AUDIT_INITIALIZED)
 		return NULL;
@@ -1903,12 +1902,14 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
 		return NULL;
 	}
 
-	audit_get_stamp(ab->ctx, &t, &serial);
+	audit_get_stamp(ab->ctx, &stamp);
 	/* cancel dummy context to enable supporting records */
 	if (ctx)
 		ctx->dummy = 0;
 	audit_log_format(ab, "audit(%llu.%03lu:%u): ",
-			 (unsigned long long)t.tv_sec, t.tv_nsec/1000000, serial);
+			 (unsigned long long)stamp.ctime.tv_sec,
+			 stamp.ctime.tv_nsec/1000000,
+			 stamp.serial);
 
 	return ab;
 }
diff --git a/kernel/audit.h b/kernel/audit.h
index b413c0420c6f..f147540862c7 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -99,6 +99,12 @@ struct audit_proctitle {
 	char	*value;	/* the cmdline field */
 };
 
+/* A timestamp/serial pair to identify an event */
+struct audit_stamp {
+	struct timespec64	ctime;	/* time of syscall entry */
+	unsigned int		serial;	/* serial number for record */
+};
+
 /* The per-task audit context. */
 struct audit_context {
 	int		    dummy;	/* must be the first element */
@@ -108,10 +114,9 @@ struct audit_context {
 		AUDIT_CTX_URING,	/* in use by io_uring */
 	} context;
 	enum audit_state    state, current_state;
-	unsigned int	    serial;     /* serial number for record */
+	struct audit_stamp  stamp;	/* event identifier */
 	int		    major;      /* syscall number */
 	int		    uring_op;   /* uring operation */
-	struct timespec64   ctime;      /* time of syscall entry */
 	unsigned long	    argv[4];    /* syscall arguments */
 	long		    return_code;/* syscall return code */
 	u64		    prio;
@@ -263,7 +268,7 @@ extern void audit_put_tty(struct tty_struct *tty);
 extern unsigned int audit_serial(void);
 #ifdef CONFIG_AUDITSYSCALL
 extern int auditsc_get_stamp(struct audit_context *ctx,
-			      struct timespec64 *t, unsigned int *serial);
+			     struct audit_stamp *stamp);
 
 extern void audit_put_watch(struct audit_watch *watch);
 extern void audit_get_watch(struct audit_watch *watch);
@@ -304,7 +309,7 @@ extern void audit_filter_inodes(struct task_struct *tsk,
 				struct audit_context *ctx);
 extern struct list_head *audit_killed_trees(void);
 #else /* CONFIG_AUDITSYSCALL */
-#define auditsc_get_stamp(c, t, s) 0
+#define auditsc_get_stamp(c, s) 0
 #define audit_put_watch(w) do { } while (0)
 #define audit_get_watch(w) do { } while (0)
 #define audit_to_watch(k, p, l, o) (-EINVAL)
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 3c0559b01677..23f72c14276d 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -994,10 +994,10 @@ static void audit_reset_context(struct audit_context *ctx)
 	 */
 
 	ctx->current_state = ctx->state;
-	ctx->serial = 0;
+	ctx->stamp.serial = 0;
 	ctx->major = 0;
 	ctx->uring_op = 0;
-	ctx->ctime = (struct timespec64){ .tv_sec = 0, .tv_nsec = 0 };
+	ctx->stamp.ctime = (struct timespec64){ .tv_sec = 0, .tv_nsec = 0 };
 	memset(ctx->argv, 0, sizeof(ctx->argv));
 	ctx->return_code = 0;
 	ctx->prio = (ctx->state == AUDIT_STATE_RECORD ? ~0ULL : 0);
@@ -1918,7 +1918,7 @@ void __audit_uring_entry(u8 op)
 
 	ctx->context = AUDIT_CTX_URING;
 	ctx->current_state = ctx->state;
-	ktime_get_coarse_real_ts64(&ctx->ctime);
+	ktime_get_coarse_real_ts64(&ctx->stamp.ctime);
 }
 
 /**
@@ -2040,7 +2040,7 @@ void __audit_syscall_entry(int major, unsigned long a1, unsigned long a2,
 	context->argv[3]    = a4;
 	context->context = AUDIT_CTX_SYSCALL;
 	context->current_state  = state;
-	ktime_get_coarse_real_ts64(&context->ctime);
+	ktime_get_coarse_real_ts64(&context->stamp.ctime);
 }
 
 /**
@@ -2511,21 +2511,17 @@ EXPORT_SYMBOL_GPL(__audit_inode_child);
 /**
  * auditsc_get_stamp - get local copies of audit_context values
  * @ctx: audit_context for the task
- * @t: timespec64 to store time recorded in the audit_context
- * @serial: serial value that is recorded in the audit_context
+ * @stamp: timestamp to record
  *
  * Also sets the context as auditable.
  */
-int auditsc_get_stamp(struct audit_context *ctx,
-		       struct timespec64 *t, unsigned int *serial)
+int auditsc_get_stamp(struct audit_context *ctx, struct audit_stamp *stamp)
 {
 	if (ctx->context == AUDIT_CTX_UNUSED)
 		return 0;
-	if (!ctx->serial)
-		ctx->serial = audit_serial();
-	t->tv_sec  = ctx->ctime.tv_sec;
-	t->tv_nsec = ctx->ctime.tv_nsec;
-	*serial    = ctx->serial;
+	if (!ctx->stamp.serial)
+		ctx->stamp.serial = audit_serial();
+	*stamp = ctx->stamp;
 	if (!ctx->prio) {
 		ctx->prio = 1;
 		ctx->current_state = AUDIT_STATE_RECORD;
-- 
2.41.0