nsp: check return value of mktime()

CID 1558654: (#1 of 1): Overflowed constant (INTEGER_OVERFLOW)
2. known_value_assign: tmp_time = mktime(&tmp_tm), its value is now -1.
3. overflow_const: Expression (uint64_t)tmp_time + 11644473600ULL,
where (uint64_t)tmp_time is known to be equal to -1, underflows the
type of (uint64_t)tmp_time + 11644473600ULL, which is type unsigned
long long.

Fixes: gromox-0~666

Author: Sergey Komarov

exch/nsp/common_util.cpp

@@ -41,6 +41,10 @@ void common_util_day_to_filetime(const char *day, FILETIME *pftime)
 	memset(&tmp_tm, 0, sizeof(tmp_tm));
 	strptime(day, "%Y-%m-%d", &tmp_tm);
 	tmp_time = mktime(&tmp_tm);
+	if (tmp_time == -1) {
+		*pftime = {};
+		return;
+	}
 	file_time = ((uint64_t)tmp_time + EPOCH_DIFF)*10000000;
 	pftime->low_datetime = file_time & 0xFFFFFFFF;
 	pftime->high_datetime = file_time >> 32;