linux-kernel - [PATCH 20/23] y2038: move itimer reset into itimer.c

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Date:   Fri,  8 Nov 2019 22:12:19 +0100
From:   Arnd Bergmann <arnd@...db.de>
To:     y2038@...ts.linaro.org, John Stultz <john.stultz@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Paul Moore <paul@...l-moore.com>,
        Stephen Smalley <sds@...ho.nsa.gov>,
        Eric Paris <eparis@...isplace.org>
Cc:     linux-kernel@...r.kernel.org, Arnd Bergmann <arnd@...db.de>,
        Stephen Boyd <sboyd@...nel.org>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>,
        Anna-Maria Gleixner <anna-maria@...utronix.de>,
        Al Viro <viro@...iv.linux.org.uk>,
        Ondrej Mosnacek <omosnace@...hat.com>, selinux@...r.kernel.org
Subject: [PATCH 20/23] 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.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 include/linux/time.h     |  9 +++++----
 kernel/time/itimer.c     | 15 +++++++++++++--
 security/selinux/hooks.c | 10 +++-------
 3 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/include/linux/time.h b/include/linux/time.h
index 27d83fd2ae61..0760a4f5a15c 100644
--- a/include/linux/time.h
+++ b/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);
 
diff --git a/kernel/time/itimer.c b/kernel/time/itimer.c
index 4664c6addf69..ce9cd19ce72e 100644
--- a/kernel/time/itimer.c
+++ b/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
 
 /**
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 9625b99e677f..c3f2e89acb87 100644
--- a/security/selinux/hooks.c
+++ b/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);
-		}
+		if (IS_ENABLED(CONFIG_POSIX_TIMERS))
+			clear_itimer();
 		spin_lock_irq(&current->sighand->siglock);
 		if (!fatal_signal_pending(current)) {
 			flush_sigqueue(&current->pending);
-- 
2.20.0