time: introduce {get,put}_itimerspec64

As we change the user space type for the timerfd and posix timer
functions to newer data types, we need some form of conversion
helpers to avoid duplicating that logic.
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

include/linux/compat.h

@@ -166,6 +166,10 @@ extern int compat_get_timeval(struct timeval *, const void __user *);
 extern int compat_put_timeval(const struct timeval *, void __user *);
 extern int compat_get_timespec64(struct timespec64 *, const void __user *);
 extern int compat_put_timespec64(const struct timespec64 *, void __user *);
+extern int get_compat_itimerspec64(struct itimerspec64 *its,
+			const struct compat_itimerspec __user *uits);
+extern int put_compat_itimerspec64(const struct itimerspec64 *its,
+			struct compat_itimerspec __user *uits);
 
 /*
  * This function convert a timespec if necessary and returns a *user

include/linux/posix-timers.h

@@ -113,5 +113,4 @@ void set_process_cpu_timer(struct task_struct *task, unsigned int clock_idx,
 void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new);
 
 void posixtimer_rearm(struct siginfo *info);
-
 #endif

include/linux/time.h

@@ -12,6 +12,10 @@ int get_timespec64(struct timespec64 *ts,
 		const struct timespec __user *uts);
 int put_timespec64(const struct timespec64 *ts,
 		struct timespec __user *uts);
+int get_itimerspec64(struct itimerspec64 *it,
+			const struct itimerspec __user *uit);
+int put_itimerspec64(const struct itimerspec64 *it,
+			struct itimerspec __user *uit);
 
 #define TIME_T_MAX	(time_t)((1UL << ((sizeof(time_t) << 3) - 1)) - 1)
 
@@ -275,4 +279,13 @@ static __always_inline void timespec_add_ns(struct timespec *a, u64 ns)
 	a->tv_nsec = ns;
 }
 
+static inline bool itimerspec64_valid(const struct itimerspec64 *its)
+{
+	if (!timespec64_valid(&(its->it_interval)) ||
+		!timespec64_valid(&(its->it_value)))
+		return false;
+
+	return true;
+}
+
 #endif

kernel/compat.c

@@ -586,6 +586,27 @@ int put_compat_itimerspec(struct compat_itimerspec __user *dst,
 	return 0;
 }
 
+int get_compat_itimerspec64(struct itimerspec64 *its,
+			const struct compat_itimerspec __user *uits)
+{
+
+	if (__compat_get_timespec64(&its->it_interval, &uits->it_interval) ||
+	    __compat_get_timespec64(&its->it_value, &uits->it_value))
+		return -EFAULT;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(get_compat_itimerspec64);
+
+int put_compat_itimerspec64(const struct itimerspec64 *its,
+			struct compat_itimerspec __user *uits)
+{
+	if (__compat_put_timespec64(&its->it_interval, &uits->it_interval) ||
+	    __compat_put_timespec64(&its->it_value, &uits->it_value))
+		return -EFAULT;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(put_compat_itimerspec64);
+
 /*
  * We currently only need the following fields from the sigevent
  * structure: sigev_value, sigev_signo, sig_notify and (sometimes

kernel/time/time.c

@@ -918,3 +918,33 @@ int put_timespec64(const struct timespec64 *ts,
 	return copy_to_user(uts, &kts, sizeof(kts)) ? -EFAULT : 0;
 }
 EXPORT_SYMBOL_GPL(put_timespec64);
+
+int get_itimerspec64(struct itimerspec64 *it,
+			const struct itimerspec __user *uit)
+{
+	int ret;
+
+	ret = get_timespec64(&it->it_interval, &uit->it_interval);
+	if (ret)
+		return ret;
+
+	ret = get_timespec64(&it->it_value, &uit->it_value);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(get_itimerspec64);
+
+int put_itimerspec64(const struct itimerspec64 *it,
+			struct itimerspec __user *uit)
+{
+	int ret;
+
+	ret = put_timespec64(&it->it_interval, &uit->it_interval);
+	if (ret)
+		return ret;
+
+	ret = put_timespec64(&it->it_value, &uit->it_value);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(put_itimerspec64);