On 24/11/2021 07:09, Michael Paquier wrote:
> On Tue, Nov 23, 2021 at 02:18:30PM -0500, Tom Lane wrote:
>> Jacob Champion <pchampion@vmware.com> writes:
>>> = Client-Side Auth Selection =
>>> The second request is for the client to stop fully trusting the server
>>> during the authentication phase. If I tell libpq to use a client
>>> certificate, for example, I don't think the server should be allowed to
>>> extract a plaintext password from my environment (at least not without
>>> my explicit opt-in).
>>
>> Yeah. I don't recall whether it's been discussed in public or not,
>> but it certainly seems like libpq should be able to be configured so
>> that (for example) it will never send a cleartext password. It's not
>> clear to me what extent of configurability would be useful, and I
>> don't want to overdesign it --- but that much at least would be a
>> good thing.
>
> I recall this part being discussed in public, but I cannot put my
> finger on the exact thread. I think that this was around when we
> discussed the open items of 10 or 11 for things around channel binding
> and how libpq was sensitive to downgrade attacks, which would mean
> around 2016 or 2017. I also recall reading (writing?) a patch that
> introduced a new connection parameter that takes in input a
> comma-separated list of keywords to allow the user to choose a set of
> auth methods accepted, failing if the server is willing to use a
> method that does not match with what the user has put in his list.
> Perhaps this last part has never reached -hackers though :)
>
> Anyway, the closest thing I can put my finger on now is that:
> https://www.postgresql.org/message-id/c5cb08f4cce46ff661ad287fadaa1b2a@postgrespro.ru
Here's a thread:
https://www.postgresql.org/message-id/227015d8417f2b4fef03f8966dbfa5cbcc4f44da.camel%40j-davis.com
The result of that thread was that we added the
channel_binding=require/prefer/disable option.
- Heikki