Horton

Re: pg_authid.rolpassword format (was Re: Password identifiers, protocol aging and SCRAM protocol)

Stephen Frost <sfrost@snowman.net>

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From: Stephen Frost <sfrost@snowman.net>
To: Michael Paquier <michael.paquier@gmail.com>
Cc: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Heikki Linnakangas <hlinnaka@iki.fi>, Robert Haas <robertmhaas@gmail.com>, Andres Freund <andres@anarazel.de>, David Steele <david@pgmasters.net>, Tom Lane <tgl@sss.pgh.pa.us>, David Fetter <david@fetter.org>, Alvaro Herrera <alvherre@2ndquadrant.com>, Magnus Hagander <magnus@hagander.net>, Julian Markwort <julian.markwort@uni-muenster.de>, PostgreSQL mailing lists <pgsql-hackers@postgresql.org>, Valery Popov <v.popov@postgrespro.ru>
Date: 2016-12-17T01:23:22Z
Lists: pgsql-hackers 
Michael,

* Michael Paquier (michael.paquier@gmail.com) wrote:
> On Sat, Dec 17, 2016 at 5:42 AM, Stephen Frost <sfrost@snowman.net> wrote:
> > * Peter Eisentraut (peter.eisentraut@2ndquadrant.com) wrote:
> >> On 12/15/16 8:40 AM, Stephen Frost wrote:
> >> > I don't follow why we can't change the syntax for CREATE USER to allow
> >> > specifying the verifier type independently.
> >>
> >> That's what the last patch set I looked at actually does.
> >
> > Well, same here, but it was quite a while ago and things have progressed
> > since then wrt SCRAM, as I understand it...
> 
> From the discussions of last year on -hackers, it was decided to *not*
> have an additional column per complains from a couple of hackers

It seems that, at best, we didn't have consensus on it.  Hopefully we
are moving in a direction of consensus.

> (Robert you were in this set at this point), and the same thing was
> concluded during the informal lunch meeting at PGcon. The point is,
> the existing SCRAM patch set can survive without touching at *all* the
> format of pg_authid. We could block SCRAM authentication when
> "password" is used in pg_hba.conf and as well as when "scram" is used
> with a plain password stored in pg_authid. Or look at the format of
> the string in the catalog if "password" is defined and decide the
> authentication protocol to follow based on that.

As I mentioned up-thread, moving forward with minimal changes to get
SCRAM in certainly makes sense, but I do think we should be open to
(and, ideally, encouraging people to work towards) having a seperate
table for verifiers with independent columns for type and verifier.

Thanks!

Stephen

Commits

  1. Support SCRAM-SHA-256 authentication (RFC 5802 and 7677).

  2. Refactor SHA2 functions and move them to src/common/.

  3. Replace isMD5() with a more future-proof way to check if pw is encrypted.

  4. Remove bogus notice that older clients might not work with MD5 passwords.

  5. Refactor the code for verifying user's password.

  6. Replace PostmasterRandom() with a stronger source, second attempt.

  7. Remove support for (insecure) crypt authentication.