Horton

Re: Is MinMaxExpr really leakproof?

Isaac Morland <isaac.morland@gmail.com>

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From: Isaac Morland <isaac.morland@gmail.com>
To: Noah Misch <noah@leadboat.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>, Stephen Frost <sfrost@snowman.net>
Date: 2018-12-31T17:40:23Z
Lists: pgsql-hackers 
On Mon, 31 Dec 2018 at 12:26, Noah Misch <noah@leadboat.com> wrote:

>
> bttextcmp() and other varstr_cmp() callers fall afoul of the same
> restriction
> with their "could not convert string to UTF-16" errors
> (
> https://postgr.es/m/CADyhKSXPwrUv%2B9LtqPAQ_gyZTv4hYbr2KwqBxcs6a3Vee1jBLQ%40mail.gmail.com
> ).
> Leaking the binary fact that an unspecified string contains an unspecified
> rare
> Unicode character is not a serious leak, however.  Also, those errors
> would be a
> substantial usability impediment if they happened much in practice; you
> couldn't
> index affected values.
>
>
I'm confused. What characters cannot be represented in UTF-16?

Commits

  1. Don't believe MinMaxExpr is leakproof without checking.

  2. Update leakproofness markings on some btree comparison functions.