1 files changed, 72 insertions, 0 deletions

diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
index dd3d59806ffa..903a82ae83f0 100644
--- a/drivers/rtc/rtc-cmos.c
+++ b/drivers/rtc/rtc-cmos.c
@@ -325,14 +325,86 @@ static void cmos_irq_disable(struct cmos_rtc *cmos, unsigned char mask)
 	cmos_checkintr(cmos, rtc_control);
 }
 
+static int cmos_validate_alarm(struct device *dev, struct rtc_wkalrm *t)
+{
+	struct cmos_rtc *cmos = dev_get_drvdata(dev);
+	struct rtc_time now;
+
+	cmos_read_time(dev, &now);
+
+	if (!cmos->day_alrm) {
+		time64_t t_max_date;
+		time64_t t_alrm;
+
+		t_max_date = rtc_tm_to_time64(&now);
+		t_max_date += 24 * 60 * 60 - 1;
+		t_alrm = rtc_tm_to_time64(&t->time);
+		if (t_alrm > t_max_date) {
+			dev_err(dev,
+				"Alarms can be up to one day in the future\n");
+			return -EINVAL;
+		}
+	} else if (!cmos->mon_alrm) {
+		struct rtc_time max_date = now;
+		time64_t t_max_date;
+		time64_t t_alrm;
+		int max_mday;
+
+		if (max_date.tm_mon == 11) {
+			max_date.tm_mon = 0;
+			max_date.tm_year += 1;
+		} else {
+			max_date.tm_mon += 1;
+		}
+		max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
+		if (max_date.tm_mday > max_mday)
+			max_date.tm_mday = max_mday;
+
+		t_max_date = rtc_tm_to_time64(&max_date);
+		t_max_date -= 1;
+		t_alrm = rtc_tm_to_time64(&t->time);
+		if (t_alrm > t_max_date) {
+			dev_err(dev,
+				"Alarms can be up to one month in the future\n");
+			return -EINVAL;
+		}
+	} else {
+		struct rtc_time max_date = now;
+		time64_t t_max_date;
+		time64_t t_alrm;
+		int max_mday;
+
+		max_date.tm_year += 1;
+		max_mday = rtc_month_days(max_date.tm_mon, max_date.tm_year);
+		if (max_date.tm_mday > max_mday)
+			max_date.tm_mday = max_mday;
+
+		t_max_date = rtc_tm_to_time64(&max_date);
+		t_max_date -= 1;
+		t_alrm = rtc_tm_to_time64(&t->time);
+		if (t_alrm > t_max_date) {
+			dev_err(dev,
+				"Alarms can be up to one year in the future\n");
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
 static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
 {
 	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
 	unsigned char mon, mday, hrs, min, sec, rtc_control;
+	int ret;
 
 	if (!is_valid_irq(cmos->irq))
 		return -EIO;
 
+	ret = cmos_validate_alarm(dev, t);
+	if (ret < 0)
+		return ret;
+
 	mon = t->time.tm_mon + 1;
 	mday = t->time.tm_mday;
 	hrs = t->time.tm_hour;