Date: Thu, 28 May 2020 12:44:04 -0400
From: Stephen Frost <sfrost@snowman.net>
To: Christoph Berg <myon@debian.org>,
	Peter Eisentraut <peter.eisentraut@2ndquadrant.com>,
	Devrim =?iso-8859-1?B?R/xuZPx6?= <devrim@gunduz.org>,
	Craig Ringer <craig@2ndquadrant.com>,
	pgsql-pkg-yum <pgsql-pkg-yum@postgresql.org>
Subject: Re: Can we stop defaulting to 'md5'?
Message-ID: <20200528164404.GA6680@tamriel.snowman.net>
References: <20200520163509.GG3418@tamriel.snowman.net>
 <20200520153337.GE3418@tamriel.snowman.net>
 <20200528163856.GB107313@msg.df7cb.de>
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Greetings,

* Christoph Berg (myon@debian.org) wrote:
> Re: Stephen Frost
> > postgresql.conf alone, but ultimately that's probably going to be up to
> > what Christoph is comfortable with.
>=20
> Re: Stephen Frost
> > If you leave it as 'md5' in pg_hba.conf, then *that* will do either md5,
> > or scram.  If you have 'scram-sha-256' in pg_hba.conf and only an 'md5'
> > password then it breaks.
>=20
> Fwiw "comfortable" and "it breaks" are the problem here. The whole
> picture is so utterly complicated that I'm still scared from reading
> the docs the first time around the time PG10 came about. In trainings
> I'm still telling people that md5 is the accepted standard because
> there's enough more interesting things to teach about PostgreSQL.

Ah, well, in trainings and talks I'm pushing to completely get rid of
md5 and to only accept using scram. :)

> Why do I have to decide *in pg_hba.conf* which hash algorithm is used?

Where else would you decide..?

> Why can't that just be "password"?

What would that mean?

> The password_encryption GUC should be the only place concerned with
> that, and it should only be used for new passwords. Existing passwords
> should just continue to work. *That* would allow seamless upgrades.

Sure, that'd be nice, but that isn't how it is today.  I argued for
similar during the scram implementation but not what ultimately ended up
happening.

> Getting this mess fixed would be good for security because then people
> will likely start using scram.

That's certainly true, though I hope we can convince people to use SCRAM
even given the modest effort required.

The point here though, really, is that *new* installations of PG have
very little reason to not use SCRAM.  The question on upgrades is
different, but that can be addressed with pg_upgradecluster, I would
think, without much trouble.

Thanks,

Stephen

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