From 7204aea835d056ca97e86298c597a079d6ee8c97 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Fri, 26 Jan 2024 13:39:37 -0500 Subject: 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 --- src/backend/utils/adt/timestamp.c | 27 +++++++++++++++++++++++---- 1 file changed, 23 insertions(+), 4 deletions(-) (limited to 'src/backend/utils/adt/timestamp.c') diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c index 6d455cdc9de..238a40d388a 100644 --- 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, ×tamp) != 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); -- cgit v1.2.3