Horton

Re: Fix overflow in DecodeInterval

Joseph Koshakow <koshy44@gmail.com>

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From: Joseph Koshakow <koshy44@gmail.com>
To: Andres Freund <andres@anarazel.de>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers@lists.postgresql.org
Date: 2022-02-18T02:45:45Z
Lists: pgsql-hackers

Attachments

Ok, so I've attached a patch with my final unprompted changes. It
contains the following two changes:

1. I found some more overflows with the ISO8601 formats and have
included some fixes.
2. I reverted the overflow checks for the seconds field. It's actually a
bit more complicated than I thought. For example consider the following
query:
    postgres=# SELECT INTERVAL '0.99999999 min 2147483647 sec';
            interval
    ----------------------
    -596523:13:09.000001
    (1 row)
This query will overflow the tm_sec field of the struct pg_tm, however
it's not actually out of range for the Interval. I'm not sure the best
way to handle this right now, but I think it would be best to leave it
for a future patch. Perhaps the time related fields in struct pg_tm
need to be changed to 64 bit ints.

- Joe Koshakow

Commits

  1. Fix portability issues in datetime parsing.

  2. Fix overflow hazards in interval input and output conversions.

  3. Add a couple more tests for interval input decoding.