security: keys: Replace time_t/timespec with time64_t

The 'struct key' will use 'time_t' which we try to remove in the
kernel, since 'time_t' is not year 2038 safe on 32bit systems.
Also the 'struct keyring_search_context' will use 'timespec' type
to record current time, which is also not year 2038 safe on 32bit
systems.

Thus this patch replaces 'time_t' with 'time64_t' which is year 2038
safe for 'struct key', and replace 'timespec' with 'time64_t' for the
'struct keyring_search_context', since we only look at the the seconds
part of 'timespec' variable. Moreover we also change the codes where
using the 'time_t' and 'timespec', and we can get current time by
ktime_get_real_seconds() instead of current_kernel_time(), and use
'TIME64_MAX' macro to initialize the 'time64_t' type variable.

Especially in proc.c file, we have replaced 'unsigned long' and 'timespec'
type with 'u64' and 'time64_t' type to save the timeout value, which means
user will get one 'u64' type timeout value by issuing proc_keys_show()
function.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <james.l.morris@oracle.com>
diff --git a/security/keys/gc.c b/security/keys/gc.c
index afb3a91..6713fee 100644
--- a/security/keys/gc.c
+++ b/security/keys/gc.c
@@ -32,7 +32,7 @@ DECLARE_WORK(key_gc_work, key_garbage_collector);
 static void key_gc_timer_func(unsigned long);
 static DEFINE_TIMER(key_gc_timer, key_gc_timer_func);
 
-static time_t key_gc_next_run = LONG_MAX;
+static time64_t key_gc_next_run = TIME64_MAX;
 static struct key_type *key_gc_dead_keytype;
 
 static unsigned long key_gc_flags;
@@ -53,12 +53,12 @@ struct key_type key_type_dead = {
  * Schedule a garbage collection run.
  * - time precision isn't particularly important
  */
-void key_schedule_gc(time_t gc_at)
+void key_schedule_gc(time64_t gc_at)
 {
 	unsigned long expires;
-	time_t now = current_kernel_time().tv_sec;
+	time64_t now = ktime_get_real_seconds();
 
-	kenter("%ld", gc_at - now);
+	kenter("%lld", gc_at - now);
 
 	if (gc_at <= now || test_bit(KEY_GC_REAP_KEYTYPE, &key_gc_flags)) {
 		kdebug("IMMEDIATE");
@@ -87,7 +87,7 @@ void key_schedule_gc_links(void)
 static void key_gc_timer_func(unsigned long data)
 {
 	kenter("");
-	key_gc_next_run = LONG_MAX;
+	key_gc_next_run = TIME64_MAX;
 	key_schedule_gc_links();
 }
 
@@ -184,11 +184,11 @@ static void key_garbage_collector(struct work_struct *work)
 
 	struct rb_node *cursor;
 	struct key *key;
-	time_t new_timer, limit;
+	time64_t new_timer, limit;
 
 	kenter("[%lx,%x]", key_gc_flags, gc_state);
 
-	limit = current_kernel_time().tv_sec;
+	limit = ktime_get_real_seconds();
 	if (limit > key_gc_delay)
 		limit -= key_gc_delay;
 	else
@@ -204,7 +204,7 @@ static void key_garbage_collector(struct work_struct *work)
 		gc_state |= KEY_GC_REAPING_DEAD_1;
 	kdebug("new pass %x", gc_state);
 
-	new_timer = LONG_MAX;
+	new_timer = TIME64_MAX;
 
 	/* As only this function is permitted to remove things from the key
 	 * serial tree, if cursor is non-NULL then it will always point to a
@@ -235,7 +235,7 @@ static void key_garbage_collector(struct work_struct *work)
 
 		if (gc_state & KEY_GC_SET_TIMER) {
 			if (key->expiry > limit && key->expiry < new_timer) {
-				kdebug("will expire %x in %ld",
+				kdebug("will expire %x in %lld",
 				       key_serial(key), key->expiry - limit);
 				new_timer = key->expiry;
 			}
@@ -276,7 +276,7 @@ static void key_garbage_collector(struct work_struct *work)
 	 */
 	kdebug("pass complete");
 
-	if (gc_state & KEY_GC_SET_TIMER && new_timer != (time_t)LONG_MAX) {
+	if (gc_state & KEY_GC_SET_TIMER && new_timer != (time64_t)TIME64_MAX) {
 		new_timer += key_gc_delay;
 		key_schedule_gc(new_timer);
 	}