[PATCH v2 1/8] cmd: date: validate date using rtc_month_days()

[Alexander Feilke]

From: Markus Niebel <Markus.Niebel at ew.tq-group.com>

The old check accepted day 0 as well as Feb 29th in non-leap years.
With this change, both day and month 0 are rejected, and the local day limit
logic is now handled by rtc_month_days(), which correctly accounts for month
length and leap years.

Because of this, special attention must be taken in the 'MMDDhhmm' format case,
as tm_year is not initialized. The leap-year calculation in rtc_month_days()
therefore depends on the value provided by the caller. This is pre-existing
behaviour, but is now made more explicit.

Signed-off-by: Markus Niebel <Markus.Niebel at ew.tq-group.com>
Signed-off-by: Alexander Feilke <alexander.feilke at ew.tq-group.com>
---
 cmd/date.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/cmd/date.c b/cmd/date.c
index d047872289c..b0da0cbd69c 100644
--- a/cmd/date.c
+++ b/cmd/date.c
@@ -167,12 +167,13 @@ int mk_date (const char *datestr, struct rtc_time *tmp)
 		/* fall thru */
 	case 12:		/* MMDDhhmmCCYY	*/
 		if (cnvrt2 (datestr+0, &val) ||
-		    val > 12) {
+		    val > 12 || val < 1) {
 			break;
 		}
 		tmp->tm_mon  = val;
-		if (cnvrt2 (datestr+2, &val) ||
-		    val > ((tmp->tm_mon==2) ? 29 : 31)) {
+		if (cnvrt2(datestr+2, &val) ||
+		    val < 1 ||
+		    val > rtc_month_days(tmp->tm_mon - 1, tmp->tm_year)) {
 			break;
 		}
 		tmp->tm_mday = val;
-- 
2.34.1