[glib: 1/2] gdatetime: Fix error handling in g_date_time_new_ordinal()

[Philip Withnall <pwithnall src gnome org>]

commit 5c6030ef8da30ef1ade25c55576c1a732d90a23a
Author: Philip Withnall <withnall endlessm com>
Date:   Wed Sep 18 12:42:39 2019 +0100

    gdatetime: Fix error handling in g_date_time_new_ordinal()
    
    It was possible to pass in (for example) an invalid hour to
    g_date_time_new_ordinal(), which would be passed on to
    g_date_time_new(), which would (correctly) return `NULL` — but then
    g_date_time_new_ordinal() would try to dereference that.
    
    Includes some test cases.
    
    oss-fuzz#16103
    oss-fuzz#17183
    
    Signed-off-by: Philip Withnall <withnall endlessm com>

 glib/gdatetime.c       | 2 ++
 glib/tests/gdatetime.c | 2 ++
 2 files changed, 4 insertions(+)
---
diff --git a/glib/gdatetime.c b/glib/gdatetime.c
index 6a99dac8e..4557e3c76 100644
--- a/glib/gdatetime.c
+++ b/glib/gdatetime.c
@@ -1220,6 +1220,8 @@ g_date_time_new_ordinal (GTimeZone *tz, gint year, gint ordinal_day, gint hour,
     return NULL;
 
   dt = g_date_time_new (tz, year, 1, 1, hour, minute, seconds);
+  if (dt == NULL)
+    return NULL;
   dt->days += ordinal_day - 1;
 
   return dt;
diff --git a/glib/tests/gdatetime.c b/glib/tests/gdatetime.c
index 23d83b7d0..d148cf528 100644
--- a/glib/tests/gdatetime.c
+++ b/glib/tests/gdatetime.c
@@ -866,6 +866,8 @@ test_GDateTime_new_from_iso8601_2 (void)
     { TRUE, "+1980-02-22T12:36:00+02:00", 1980, 2, 22, 12, 36, 0, 0, 2 * G_TIME_SPAN_HOUR },
     { TRUE, "1990-11-01T10:21:17     ", 1990, 11, 1, 10, 21, 17, 0, 0 },
     */
+    { FALSE, "1719W462 407777-07", 0, 0, 0, 0, 0, 0, 0, 0 },
+    { FALSE, "4011090 260528Z", 0, 0, 0, 0, 0, 0, 0, 0 },
   };
   GTimeZone *tz = NULL;
   GDateTime *dt = NULL;