Re: Proposed patch for key managment

On Fri, Dec 18, 2020 at 10:01:22AM +0900, Michael Paquier wrote:
> On Thu, Dec 17, 2020 at 12:10:22PM -0500, Bruce Momjian wrote:
> > On Thu, Dec 17, 2020 at 11:39:55AM -0500, Stephen Frost wrote:
> >> I don't think there's any need for us to implement a fallback
> >> implementation of AES. I'm not entirely sure we need it for hashes
> >> but since we've already got it...
>
> We need fallback implementations for cryptohashes (MD5, SHA1/2) and
> HMAC because we have SCRAM authentication, pgcrypto and SQL functions
> that should be able to work even when not building with any SSL
> libraries. So that's here to stay to ensure compatibility with what
> we do. All this stuff is already in the tree for ages, it was just
> not shaped for a more centralized reuse.

One question is whether we want to support cluster file encryption
without OpenSSL --- right now we can't. I am wondering if we really
need the hardware acceleration of OpenSSL for AES so doing our own AES
implementation might not even make sense, performance-wise.

> > Agreed. I think there is serious risk we would do AES in a different
> > way than OpenSSL, especially if I did it. ;-) We can add a native AES
> > one day if we want, but as stated by Michael Paquier, it has to be
> > tested so we are sure it returns exactly the same values as OpenSSL.
>
> I think that it would be good to put some generalization here, and
> look at options that are offered by other SSL libraries, like libnss
> so as we don't finish with a design that restricts the use of a given
> feature only to OpenSSL.

Uh, you mean the C API or the user API? I don't think we have any
OpenSSL requirement at the user level, except that my examples use
command-line openssl to generate the passphrase.

I split apart my patch to create cipher{_openssl}.c and hmac{_openssl}.c
so the single HMAC function is not in the cipher file anymore, attached.

--
Bruce Momjian <bruce(at)momjian(dot)us> https://momjian.us
EnterpriseDB https://enterprisedb.com

The usefulness of a cup is in its emptiness, Bruce Lee