From: | Bruce Momjian <bruce(at)momjian(dot)us> |
---|---|
To: | Sehrope Sarkuni <sehrope(at)jackdb(dot)com> |
Cc: | Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>, Joe Conway <mail(at)joeconway(dot)com>, Antonin Houska <ah(at)cybertec(dot)at>, Stephen Frost <sfrost(at)snowman(dot)net>, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Haribabu Kommi <kommi(dot)haribabu(at)gmail(dot)com>, "Moon, Insung" <Moon_Insung_i3(at)lab(dot)ntt(dot)co(dot)jp>, Ibrar Ahmed <ibrar(dot)ahmad(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: [Proposal] Table-level Transparent Data Encryption (TDE) and Key Management Service (KMS) |
Date: | 2019-08-12 22:23:25 |
Message-ID: | 20190812222324.jx5sdxlnxzn5g42h@momjian.us |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On Wed, Jul 31, 2019 at 09:43:00AM -0400, Sehrope Sarkuni wrote:
> On Wed, Jul 31, 2019 at 2:32 AM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
> For WAL encryption, before flushing WAL we encrypt whole 8k WAL page
> and then write only the encrypted data of the new WAL record using
> pg_pwrite() rather than write whole encrypted page. So each time we
> encrypt 8k WAL page we end up with encrypting different data with the
> same key+nonce but since we don't write to the disk other than space
> where we actually wrote WAL records it's not a problem. Is that right?
>
> Ah, this is what I was referring to in my previous mail. I'm not familiar with
> how the writes happen yet (reading up...) but, yes, we would need to ensure
> that encrypted data is not written more than once (i.e. no writing of encrypt
> (zero) followed by writing of encrypt(non-zero) at the same spot).
No one replied to this comment, so I will state here that we never write
zeros to the WAL and go back and write something else --- the WAL is
append-only. We might do that for heap/index pages, but they would get
a new LSN (and hence a new IV) when that happens.
--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ As you are, so once was I. As I am, so you will be. +
+ Ancient Roman grave inscription +
From | Date | Subject | |
---|---|---|---|
Next Message | Peter Geoghegan | 2019-08-12 22:23:28 | Re: Do not check unlogged indexes on standby |
Previous Message | Bruce Momjian | 2019-08-12 21:50:31 | Re: [Proposal] Table-level Transparent Data Encryption (TDE) and Key Management Service (KMS) |