Horton

Re: storing an explicit nonce

Stephen Frost <sfrost@snowman.net>

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From: Stephen Frost <sfrost@snowman.net>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>, Amit Kapila <amit.kapila16@gmail.com>, Andres Freund <andres@anarazel.de>, Bruce Momjian <bruce@momjian.us>, Masahiko Sawada <masahiko.sawada@2ndquadrant.com>, Masahiko Sawada <sawada.mshk@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Thomas Munro <thomas.munro@gmail.com>, Tom Kincaid <tomjohnkincaid@gmail.com>
Date: 2021-05-25T20:34:10Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Rethink method for assigning OIDs to the template0 and postgres DBs.

  2. pg_upgrade: Preserve database OIDs.

  3. pg_upgrade: Preserve relfilenodes and tablespace OIDs.

  4. Fix for new Boolean node

  5. Improve error handling of HMAC computations

  6. Add macro RelationIsPermanent() to report relation permanence

  7. Enhance nbtree index tuple deletion.

Greetings,

On Tue, May 25, 2021 at 15:09 Robert Haas <robertmhaas@gmail.com> wrote:

> On Tue, May 25, 2021 at 2:45 PM Bruce Momjian <bruce@momjian.us> wrote:
> > Well, if we create a separate nonce counter, we still need to make sure
> > it doesn't go backwards during a crash, so we have to WAL log it
>
> I think we don't really need a global counter, do we? We could simply
> increment the nonce every time we write the page. If we want to avoid
> using the same IV for different pages, then 8 bytes of the nonce could
> store a value that's different for every page, and the other 8 bytes
> could store a counter. Presumably we won't manage to write the same
> page more than 2^64 times, since LSNs are limited to be <2^64, and
> those are consumed more than 1 byte at a time for every change to any
> page anywhere.


The nonce does need to be absolutely unique for a given encryption key and
therefore needs to be global in some form.

Thanks!

Stephen