Greetings, * Bruce Momjian (br...@momjian.us) wrote: > On Tue, Oct 12, 2021 at 08:40:17AM +0300, Ants Aasma wrote: > > On Mon, 11 Oct 2021 at 22:15, Bruce Momjian <br...@momjian.us> wrote: > > > > > Yes, that's the direction that I was thinking also and specifically > > with > > > XTS as the encryption algorithm to allow us to exclude the LSN but > > keep > > > everything else, and to address the concern around the nonce/tweak/etc > > > being the same sometimes across multiple writes. Another thing to > > > consider is if we want to encrypt zero'd page. There was a point > > > brought up that if we do then we are encrypting a fair bit of very > > > predictable bytes and that's not great (though there's a fair bit > > about > > > our pages that someone could quite possibly predict anyway based on > > > table structures and such...). I would think that if it's easy enough > > > to not encrypt zero'd pages that we should avoid doing so. Don't > > recall > > > offhand which way zero'd pages were being handled already but thought > > it > > > made sense to mention that as part of this discussion. > > > > Yeah, I wanted to mention that. I don't see any security difference > > between fully-zero pages, pages with headers and no tuples, and pages > > with headers and only a few tuples. If any of those are insecure, they > > all are. Therefore, I don't see any reason to treat them differently. > > > > > > We had to special case zero pages and not encrypt them because as far as I > > can > > tell, there is no atomic way to extend a file and initialize it to > > Enc(zero) in > > the same step. > > Oh, good point. Yeah, we will need to handle that.
Not sure what's meant here by 'handle that', but I don't see any particular reason to avoid doing exactly the same for zero pages with TDE in core..? I don't think there's any reason we need to make things complicated to ensure that we encrypt entirely empty pages. Thanks, Stephen
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