y2038: move itimer reset into itimer.c

Preparing for a change to the itimer internals, stop using the
do_setitimer() symbol and instead use a new higher-level interface.

The do_getitimer()/do_setitimer functions can now be made static,
allowing the compiler to potentially produce better object code.
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

include/linux/time.h

@@ -35,10 +35,11 @@ extern time64_t mktime64(const unsigned int year, const unsigned int mon,
 extern u32 (*arch_gettimeoffset)(void);
 #endif
 
-struct itimerval;
-extern int do_setitimer(int which, struct itimerval *value,
-			struct itimerval *ovalue);
-extern int do_getitimer(int which, struct itimerval *value);
+#ifdef CONFIG_POSIX_TIMERS
+extern void clear_itimer(void);
+#else
+static inline void clear_itimer(void) {}
+#endif
 
 extern long do_utimes(int dfd, const char __user *filename, struct timespec64 *times, int flags);
 

kernel/time/itimer.c

@@ -73,7 +73,7 @@ static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
 	value->it_interval = ns_to_timeval(interval);
 }
 
-int do_getitimer(int which, struct itimerval *value)
+static int do_getitimer(int which, struct itimerval *value)
 {
 	struct task_struct *tsk = current;
 
@@ -197,7 +197,7 @@ static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
 #define timeval_valid(t) \
 	(((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC))
 
-int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
+static int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
 {
 	struct task_struct *tsk = current;
 	struct hrtimer *timer;
@@ -249,6 +249,17 @@ int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
 	return 0;
 }
 
+#ifdef CONFIG_SECURITY_SELINUX
+void clear_itimer(void)
+{
+	struct itimerval v = {};
+	int i;
+
+	for (i = 0; i < 3; i++)
+		do_setitimer(i, &v, NULL);
+}
+#endif
+
 #ifdef __ARCH_WANT_SYS_ALARM
 
 /**

security/selinux/hooks.c

@@ -2549,9 +2549,8 @@ static void selinux_bprm_committing_creds(struct linux_binprm *bprm)
 static void selinux_bprm_committed_creds(struct linux_binprm *bprm)
 {
 	const struct task_security_struct *tsec = selinux_cred(current_cred());
-	struct itimerval itimer;
 	u32 osid, sid;
-	int rc, i;
+	int rc;
 
 	osid = tsec->osid;
 	sid = tsec->sid;
@@ -2569,11 +2568,8 @@ static void selinux_bprm_committed_creds(struct linux_binprm *bprm)
 	rc = avc_has_perm(&selinux_state,
 			  osid, sid, SECCLASS_PROCESS, PROCESS__SIGINH, NULL);
 	if (rc) {
-		if (IS_ENABLED(CONFIG_POSIX_TIMERS)) {
-			memset(&itimer, 0, sizeof itimer);
-			for (i = 0; i < 3; i++)
-				do_setitimer(i, &itimer, NULL);
-		}
+		clear_itimer();
+
 		spin_lock_irq(&current->sighand->siglock);
 		if (!fatal_signal_pending(current)) {
 			flush_sigqueue(&current->pending);