Re: [Proposal] Table-level Transparent Data Encryption (TDE) and Key Management Service (KMS)

Greetings,

* Bruce Momjian (bruce(at)momjian(dot)us) wrote:
> On Sat, Aug 17, 2019 at 08:16:06AM +0200, Antonin Houska wrote:
> > Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> >
> > > On Thu, Aug 15, 2019 at 09:01:05PM -0400, Stephen Frost wrote:
> > > > * Bruce Momjian (bruce(at)momjian(dot)us) wrote:
> > > > > Why would it not be simpler to have the cluster_passphrase_command run
> > > > > whatever command-line program it wants? If you don't want to use a
> > > > > shell command, create an executable and call that.
> > > >
> > > > Having direct integration with a KMS would certainly be valuable, and I
> > > > don't see a reason to deny users that option if someone would like to
> > > > spend time implementing it- in addition to a simpler mechanism such as a
> > > > passphrase command, which I believe is what was being suggested here.
> > >
> > > OK, I am just trying to see why we would not use the
> > > cluster_passphrase_command-like interface to do that.
> >
> > One problem that occurs to me is that PG may need to send some sort of
> > credentials to the KMS. If it runs a separate process to execute the command,
> > it needs to pass those credentials to it. Whether it does so via parameters or
> > environment variables, both can be seen by other users.
>
> Yes, that would be a good reason to use an external library, if we can't
> figure out a clean API like opening a pipe into the command-line tool
> and piping in the secret.

Having to install something additional to make that whole mechanism
happen would also be less than ideal, imv. That includes even something
as install-X and then configure passphrase_command. Our experience with
archive_command shows that it really isn't a very good approach, even
when everything can be passed in on a command line.

Thanks,

Stephen