[PATCH v30 23/28] Audit: Create audit_stamp structure

Casey Schaufler
2021-11-24T02:09:13Z

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 | 12 +++++++++---
kernel/auditsc.c | 22 +++++++++-------------
3 files changed, 27 insertions(+), 24 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 a2fca1134519..56560846f3b0 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 +114,10 @@ struct audit_context {
AUDIT_CTX_URING, /* in use by io_uring */
} context;
enum audit_state state, current_state;
+ struct audit_stamp stamp; /* event identifier */
unsigned int serial; /* serial number for record */
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;
@@ -261,7 +267,7 @@ 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);
@@ -302,7 +308,7 @@ 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 0d0351dc0c52..e6868d072648 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -983,10 +983,10 @@ 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);
@@ -1889,7 +1889,7 @@ 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);
}

/**
@@ -2005,7 +2005,7 @@ 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);
}

/**
@@ -2474,21 +2474,17 @@ 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;