[PATCH v29 23/28] Audit: Create audit_stamp structure

From: Casey Schaufler <casey@schaufler-ca.com>
To: casey.schaufler@intel.com, jmorris@namei.org,
	linux-security-module@vger.kernel.org, selinux@vger.kernel.org
Cc: casey@schaufler-ca.com, linux-audit@redhat.com,
	keescook@chromium.org, john.johansen@canonical.com,
	penguin-kernel@i-love.sakura.ne.jp, paul@paul-moore.com,
	sds@tycho.nsa.gov, linux-kernel@vger.kernel.org
Subject: [PATCH v29 23/28] Audit: Create audit_stamp structure
Date: Fri, 24 Sep 2021 10:54:36 -0700	[thread overview]
Message-ID: <20210924175441.7943-24-casey@schaufler-ca.com> (raw)
In-Reply-To: <20210924175441.7943-1-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>
---
 kernel/audit.c   | 17 +++++++++--------
 kernel/audit.h   | 13 +++++++++----
 kernel/auditsc.c | 18 +++++++-----------
 3 files changed, 25 insertions(+), 23 deletions(-)

diff --git a/kernel/audit.c b/kernel/audit.c
index 3c6e88a9ff62..069cd4c81a61 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1786,11 +1786,11 @@ 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();
 	}
 }
 
@@ -1813,8 +1813,7 @@ 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;
@@ -1867,12 +1866,14 @@ 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 f3ff2bd31459..90d98121895f 100644
--- a/kernel/audit.h
+++ b/kernel/audit.h
@@ -98,14 +98,19 @@ 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 */
 	int		    in_syscall;	/* 1 if task is in a syscall */
 	enum audit_state    state, current_state;
-	unsigned int	    serial;     /* serial number for record */
+	struct audit_stamp  stamp;	/* event identifier */
 	int		    major;      /* syscall number */
-	struct timespec64   ctime;      /* time of syscall entry */
 	unsigned long	    argv[4];    /* syscall arguments */
 	long		    return_code;/* syscall return code */
 	u64		    prio;
@@ -254,7 +259,7 @@ extern void audit_put_tty(struct tty_struct *tty);
 #ifdef CONFIG_AUDITSYSCALL
 extern unsigned int audit_serial(void);
 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);
@@ -295,7 +300,7 @@ 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 e960410cf4e4..0fef12638d8a 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1700,11 +1700,11 @@ void __audit_syscall_entry(int major, unsigned long a1, unsigned long a2,
 	context->argv[1]    = a2;
 	context->argv[2]    = a3;
 	context->argv[3]    = a4;
-	context->serial     = 0;
+	context->stamp.serial = 0;
 	context->in_syscall = 1;
 	context->current_state  = state;
 	context->ppid       = 0;
-	ktime_get_coarse_real_ts64(&context->ctime);
+	ktime_get_coarse_real_ts64(&context->stamp.ctime);
 }
 
 /**
@@ -2209,21 +2209,17 @@ 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->in_syscall)
 		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;
-- 
2.31.1

