Detect Julian-date overflow in timestamp[tz]_pl_interval.

We perform addition of the days field of an interval via
arithmetic on the Julian-date representation of the timestamp's date.
This step is subject to int32 overflow, and we also should not let
the Julian date become very negative, for fear of weird results from
j2date.  (In the timestamptz case, allow a Julian date of -1 to pass,
since it might convert back to zero after timezone rotation.)

The additions of the months and microseconds fields could also
overflow, of course.  However, I believe we need no additional
checks there; the existing range checks should catch such cases.
The difficulty here is that j2date's magic modular arithmetic could
produce something that looks like it's in-range.

Per bug #18313 from Christian Maurer.  This has been wrong for
a long time, so back-patch to all supported branches.

Discussion: https://postgr.es/m/18313-64d2c8952d81e84b@postgresql.org

diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c
index 6d455cdc9de615f8d49c03c6bc6c64989f5e1669..238a40d388a295d0ccc01471d09832cc4b44cd10 100644 (file)
--- a/src/backend/utils/adt/timestamp.c
+++ b/src/backend/utils/adt/timestamp.c
@@ -2966,8 +2966,16 @@ timestamp_pl_interval(PG_FUNCTION_ARGS)
                        (errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
                         errmsg("timestamp out of range")));
 
-           /* Add days by converting to and from Julian */
-           julian = date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) + span->day;
+           /*
+            * Add days by converting to and from Julian.  We need an overflow
+            * check here since j2date expects a non-negative integer input.
+            */
+           julian = date2j(tm->tm_year, tm->tm_mon, tm->tm_mday);
+           if (pg_add_s32_overflow(julian, span->day, &julian) ||
+               julian < 0)
+               ereport(ERROR,
+                       (errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
+                        errmsg("timestamp out of range")));
            j2date(julian, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
 
            if (tm2timestamp(tm, fsec, NULL, &timestamp) != 0)
@@ -3080,8 +3088,19 @@ timestamptz_pl_interval_internal(TimestampTz timestamp,
                        (errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
                         errmsg("timestamp out of range")));
 
-           /* Add days by converting to and from Julian */
-           julian = date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) + span->day;
+           /*
+            * Add days by converting to and from Julian.  We need an overflow
+            * check here since j2date expects a non-negative integer input.
+            * In practice though, it will give correct answers for small
+            * negative Julian dates; we should allow -1 to avoid
+            * timezone-dependent failures, as discussed in timestamp.h.
+            */
+           julian = date2j(tm->tm_year, tm->tm_mon, tm->tm_mday);
+           if (pg_add_s32_overflow(julian, span->day, &julian) ||
+               julian < -1)
+               ereport(ERROR,
+                       (errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
+                        errmsg("timestamp out of range")));
            j2date(julian, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
 
            tz = DetermineTimeZoneOffset(tm, attimezone);

diff --git a/src/test/regress/expected/horology.out b/src/test/regress/expected/horology.out
index e63e5b30fee8e16f979bc5372be6c97e1d41bf35..f3cda4afe19e8b8aaeaaa749a2cc874ea5c0682b 100644 (file)
--- a/src/test/regress/expected/horology.out
+++ b/src/test/regress/expected/horology.out
@@ -482,6 +482,8 @@ SELECT timestamp without time zone 'Jan 1, 4713 BC' + interval '109203489 days'
  Sun Dec 31 00:00:00 294276
 (1 row)
 
+SELECT timestamp without time zone '2000-01-01' - interval '2483590 days' AS "out of range";
+ERROR:  timestamp out of range
 SELECT timestamp without time zone '12/31/294276' - timestamp without time zone '12/23/1999' AS "106751991 Days";
   106751991 Days  
 ------------------
@@ -742,6 +744,8 @@ SELECT timestamp with time zone '1999-12-01' + interval '1 month - 1 second' AS
  Fri Dec 31 23:59:59 1999 PST
 (1 row)
 
+SELECT timestamp with time zone '2000-01-01' - interval '2483590 days' AS "out of range";
+ERROR:  timestamp out of range
 SELECT (timestamp with time zone 'today' = (timestamp with time zone 'yesterday' + interval '1 day')) as "True";
  True 
 ------

diff --git a/src/test/regress/sql/horology.sql b/src/test/regress/sql/horology.sql
index f7f8c8d2dd9eba2b116a97239a7b3274a5f33353..8621446afdb5ab2733eb5c9a900de656b2e1b8fe 100644 (file)
--- a/src/test/regress/sql/horology.sql
+++ b/src/test/regress/sql/horology.sql
@@ -120,6 +120,7 @@ SELECT timestamp without time zone '1999-12-01' + interval '1 month - 1 second'
 SELECT timestamp without time zone 'Jan 1, 4713 BC' + interval '106000000 days' AS "Feb 23, 285506";
 SELECT timestamp without time zone 'Jan 1, 4713 BC' + interval '107000000 days' AS "Jan 20, 288244";
 SELECT timestamp without time zone 'Jan 1, 4713 BC' + interval '109203489 days' AS "Dec 31, 294276";
+SELECT timestamp without time zone '2000-01-01' - interval '2483590 days' AS "out of range";
 SELECT timestamp without time zone '12/31/294276' - timestamp without time zone '12/23/1999' AS "106751991 Days";
 
 -- Shorthand values
@@ -151,6 +152,7 @@ SELECT timestamp with time zone '1996-03-01' - interval '1 second' AS "Feb 29";
 SELECT timestamp with time zone '1999-03-01' - interval '1 second' AS "Feb 28";
 SELECT timestamp with time zone '2000-03-01' - interval '1 second' AS "Feb 29";
 SELECT timestamp with time zone '1999-12-01' + interval '1 month - 1 second' AS "Dec 31";
+SELECT timestamp with time zone '2000-01-01' - interval '2483590 days' AS "out of range";
 
 SELECT (timestamp with time zone 'today' = (timestamp with time zone 'yesterday' + interval '1 day')) as "True";
 SELECT (timestamp with time zone 'today' = (timestamp with time zone 'tomorrow' - interval '1 day')) as "True";