Message-ID: <4b9923d6-65f3-46d5-8360-462f8381fbee@iki.fi>
Date: Wed, 17 Dec 2025 11:03:07 +0200
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Subject: Re: Serverside SNI support in libpq
To: Daniel Gustafsson <daniel@yesql.se>,
 Jacob Champion <jacob.champion@enterprisedb.com>
Cc: Jelte Fennema-Nio <postgres@jeltef.nl>, Dewei Dai <daidewei1970@163.com>,
 "li.evan.chao" <li.evan.chao@gmail.com>,
 Michael Paquier <michael@paquier.xyz>, Andres Freund <andres@anarazel.de>,
 Pgsql Hackers <pgsql-hackers@lists.postgresql.org>
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From: Heikki Linnakangas <hlinnaka@iki.fi>
In-Reply-To: <FB2759EB-C8DB-49FA-800F-7010C65EB8DF@yesql.se>
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On 12/12/2025 13:41, Daniel Gustafsson wrote:
>> On Wed, Dec 3, 2025 at 1:57 AM Heikki Linnakangas <hlinnaka@iki.fi> wrote:
>>> Maybe.  I'm not a big fan of magic-file-exist configurations
>>
>> Me neither. (I especially don't like the idea of ignoring a
>> certificate+key setting that a user has taken the time to put into a
>> config.)

+1

> I wonder if the way forward is to do both?  Heikki has a good point that when
> working with pg_hosts.conf it should be clear from just that file what the
> final config will be, and in the previous version that wasn't the case since
> the ssl_snimode GUC set operation modes.  At the same time, Jacob has a point
> that overriding configuration just because pg_hosts exists isn't transparent.
> 
> Adding a boolean GUC which turns ph_hosts (and thus SNI) on or off can perhaps
> fix both complaints?  If the GUC is on, pg_hosts - and only pg_hosts - is used
> for configuring secrets.  By using the * fallback and no_sni rule in pg_hosts
> all variations of configs can be achieved.  If the GUC is off, then the regular
> SSL GUCs are used and pg_host is never considered (and thus SNI is not
> possible).
> 
> Such a GUC wouldn't make the patch all that much different from what it is
> right now. What do you think about that middleground proposal?

I like that.

Instead of a boolean GUC, it could perhaps be a path to the pg_hosts 
file. I haven't thought this through but somehow it feels more natural 
to me than a "read this file or not" setting.

- Heikki