MDEV-456 An out-of-range datetime value (with a 5-digit year) can be created and cause troubles

fix Item_func_add_time::get_date() to generate valid dates.
Move the validity check inside get_date_from_daynr()
instead of relying on callers
(5 that had it, and 2 that did not, but should've)

mysql-test/r/datetime_456.result

+create table t1 (d datetime);
+insert t1 values (addtime('9999-12-31 23:59:59', '00:00:01')),
+(from_days(3652499));
+select * from t1;
+d
+NULL
+NULL
+drop table t1;

mysql-test/t/datetime_456.test

+#
+# MDEV-456 An out-of-range datetime value (with a 5-digit year) can be created and cause troubles
+#
+create table t1 (d datetime);
+insert t1 values (addtime('9999-12-31 23:59:59', '00:00:01')),
+                 (from_days(3652499));
+select * from t1;
+drop table t1;

sql/item_timefunc.cc

@@ -341,9 +341,8 @@ static bool extract_date_time(DATE_TIME_FORMAT *format,
   {
     uint days;
     days= calc_daynr(l_time->year,1,1) +  yearday - 1;
-    if (days <= 0 || days > MAX_DAY_NUMBER)
+    if (get_date_from_daynr(days,&l_time->year,&l_time->month,&l_time->day))
       goto err;
-    get_date_from_daynr(days,&l_time->year,&l_time->month,&l_time->day);
   }
 
   if (week_number >= 0 && weekday)
@@ -388,9 +387,8 @@ static bool extract_date_time(DATE_TIME_FORMAT *format,
              (weekday - 1);
     }
 
-    if (days <= 0 || days > MAX_DAY_NUMBER)
+    if (get_date_from_daynr(days,&l_time->year,&l_time->month,&l_time->day))
       goto err;
-    get_date_from_daynr(days,&l_time->year,&l_time->month,&l_time->day);
   }
 
   if (l_time->month > 12 || l_time->day > 31 || l_time->hour > 23 || 
@@ -1385,13 +1383,16 @@ bool Item_func_from_days::get_date(MYSQL_TIME *ltime, uint fuzzy_date)
   if ((null_value=args[0]->null_value))
     return 1;
   bzero(ltime, sizeof(MYSQL_TIME));
-  get_date_from_daynr((long) value, &ltime->year, &ltime->month, &ltime->day);
 
-  if ((null_value= ((fuzzy_date & TIME_NO_ZERO_DATE) && ltime->year == 0)))
-    return TRUE;
+  if (get_date_from_daynr((long) value, &ltime->year, &ltime->month,
+                          &ltime->day))
+    return (null_value= 1);
+
+  if ((fuzzy_date & TIME_NO_ZERO_DATE) && ltime->year == 0)
+    return (null_value= 1);
 
   ltime->time_type= MYSQL_TIMESTAMP_DATE;
-  return 0;
+  return (null_value= 0);
 }
 
 
@@ -2388,14 +2389,12 @@ bool Item_func_makedate::get_date(MYSQL_TIME *ltime, uint fuzzy_date)
     year= year_2000_handling(year);
 
   days= calc_daynr(year,1,1) + daynr - 1;
-  /* Day number from year 0 to 9999-12-31 */
-  if (days >= 0 && days <= MAX_DAY_NUMBER)
-  {
-    bzero(ltime, sizeof(*ltime));
+  if (get_date_from_daynr(days, &ltime->year, &ltime->month, &ltime->day))
+    goto err;
   ltime->time_type= MYSQL_TIMESTAMP_DATE;
-    get_date_from_daynr(days, &ltime->year, &ltime->month, &ltime->day);
+  ltime->neg= 0;
+  ltime->hour= ltime->minute= ltime->second= ltime->second_part= 0;
   return (null_value= 0);
-  }
 
 err:
   return (null_value= 1);
@@ -2489,8 +2488,8 @@ bool Item_func_add_time::get_date(MYSQL_TIME *ltime, uint fuzzy_date)
 
   if (!is_time)
   {
-    get_date_from_daynr(days,&ltime->year,&ltime->month,&ltime->day);
-    if (!ltime->day)
+    if (get_date_from_daynr(days,&ltime->year,&ltime->month,&ltime->day) ||
+        !ltime->day)
       return (null_value= 1);
     return (null_value= 0);
   }

sql/mysql_priv.h

@@ -2445,7 +2445,7 @@ void free_field_buffers_larger_than(TABLE *table, uint32 size);
 int set_zone(int nr,int min_zone,int max_zone);
 ulong convert_period_to_month(ulong period);
 ulong convert_month_to_period(ulong month);
-void get_date_from_daynr(long daynr,uint *year, uint *month,
+bool get_date_from_daynr(long daynr,uint *year, uint *month,
 			 uint *day);
 my_time_t TIME_to_timestamp(THD *thd, const MYSQL_TIME *t, uint *error);
 bool str_to_time_with_warn(const char *str,uint length,MYSQL_TIME *l_time,

sql/time.cc

@@ -24,9 +24,9 @@
 #include <m_ctype.h>
 
 
-	/* Some functions to calculate dates */
+#define MAX_DAY_NUMBER 3652424L
 
-#ifndef TESTTIME
+	/* Some functions to calculate dates */
 
 /*
   Name description of interval names used in statements.
@@ -146,19 +146,16 @@ uint calc_week(MYSQL_TIME *l_time, uint week_behaviour, uint *year)
 	/* Change a daynr to year, month and day */
 	/* Daynr 0 is returned as date 00.00.00 */
 
-void get_date_from_daynr(long daynr,uint *ret_year,uint *ret_month,
+bool get_date_from_daynr(long daynr,uint *ret_year,uint *ret_month,
 			 uint *ret_day)
 {
   uint year,temp,leap_day,day_of_year,days_in_year;
   uchar *month_pos;
   DBUG_ENTER("get_date_from_daynr");
 
-  if (daynr <= 365L || daynr >= 3652500)
-  {						/* Fix if wrong daynr */
-    *ret_year= *ret_month = *ret_day =0;
-  }
-  else
-  {
+  if (daynr < 365 || daynr > MAX_DAY_NUMBER)
+    DBUG_RETURN(1);
+
   year= (uint) (daynr*100 / 36525L);
   temp=(((year-1)/100+1)*3)/4;
   day_of_year=(uint) (daynr - (long) year * 365L) - (year-1)/4 +temp;
@@ -184,8 +181,7 @@ void get_date_from_daynr(long daynr,uint *ret_year,uint *ret_month,
     ;
   *ret_year=year;
   *ret_day=day_of_year+leap_day;
-  }
-  DBUG_VOID_RETURN;
+  DBUG_RETURN(0);
 }
 
 	/* Functions to handle periods */
@@ -805,7 +801,6 @@ void make_truncated_value_warning(THD *thd,
 
 
 /* Daynumber from year 0 to 9999-12-31 */
-#define MAX_DAY_NUMBER 3652424L
 #define COMBINE(X)                                                      \
                (((((X)->day * 24LL + (X)->hour) * 60LL +                \
                    (X)->minute) * 60LL + (X)->second)*1000000LL +       \
@@ -872,19 +867,18 @@ bool date_add_interval(MYSQL_TIME *ltime, interval_type int_type,
     daynr= usec;
 
     /* Day number from year 0 to 9999-12-31 */
-    if ((ulonglong) daynr > MAX_DAY_NUMBER)
+    if (get_date_from_daynr((long) daynr, &ltime->year, &ltime->month,
+                            &ltime->day))
       goto invalid_date;
-    get_date_from_daynr((long) daynr, &ltime->year, &ltime->month,
-                        &ltime->day);
     break;
   }
   case INTERVAL_WEEK:
     period= (calc_daynr(ltime->year,ltime->month,ltime->day) +
              sign * (long) interval.day);
     /* Daynumber from year 0 to 9999-12-31 */
-    if ((ulong) period > MAX_DAY_NUMBER)
+    if (get_date_from_daynr((long) period,&ltime->year,&ltime->month,
+                            &ltime->day))
       goto invalid_date;
-    get_date_from_daynr((long) period,&ltime->year,&ltime->month,&ltime->day);
     break;
   case INTERVAL_YEAR:
     ltime->year+= sign * (long) interval.year;
@@ -1034,4 +1028,3 @@ int my_time_compare(MYSQL_TIME *a, MYSQL_TIME *b)
   return 0;
 }
 
-#endif