icaltime_as_timet: Support dates staring with year 1902 also for 32-bit time_t. Add a range guard for years from 1902 to 10000 also for 64-bit time_t.

2 files changed, 11 insertions, 2 deletions

diff --git a/src/libical/icaltime.c b/src/libical/icaltime.c
index fe03aee5..b8b0f11b 100644
--- a/src/libical/icaltime.c
+++ b/src/libical/icaltime.c
@@ -120,10 +120,13 @@ static time_t make_time(struct tm *tm, int tzm)
     if (tm->tm_mon < 0 || tm->tm_mon > 11)
         return ((time_t) - 1);
 
+    if (tm->tm_year < 2)
+        return ((time_t)-1);
+
 #if (SIZEOF_TIME_T == 4)
     /* check that year specification within range */
 
-    if (tm->tm_year < 70 || tm->tm_year > 138)
+    if (tm->tm_year > 138)
         return ((time_t) - 1);
 
     /* check for upper bound of Jan 17, 2038 (to avoid possibility of
@@ -136,6 +139,11 @@ static time_t make_time(struct tm *tm, int tzm)
             return ((time_t) - 1);
         }
     }
+#else
+    /* We don't support years >= 10000, because the function has not been tested at this range. */
+    if (tm->tm_year >= 8100) {
+        return ((time_t)-1);
+    }
 #endif /* SIZEOF_TIME_T */
 
     /*
diff --git a/src/libical/icaltime.h b/src/libical/icaltime.h
index 816eac6f..2de53c9f 100644
--- a/src/libical/icaltime.h
+++ b/src/libical/icaltime.h
@@ -199,7 +199,8 @@ LIBICAL_ICAL_EXPORT struct icaltimetype icaltime_from_day_of_year(const int doy,
  * only pass an icaltime in UTC, since no conversion is done.  Even in that case,
  * it's probably better to just use icaltime_as_timet_with_zone().
  *
- * The return value is defined for dates starting with 1902-01-01 until 10000-01-01 (excl.).
+ * The return value is defined for dates ranging from 1902-01-01 (incl.) up to 10000-01-01 (excl.)
+ * if time_t has a size of 64 bit and up to 2038-01-18 (excl.) if it has a size of 32 bit.
  */
 LIBICAL_ICAL_EXPORT time_t icaltime_as_timet(const struct icaltimetype);