Re: Postgres 11 release notes

On Wed, May 16, 2018 at 09:09:22PM -0400, Bruce Momjian wrote:
> On Thu, May 17, 2018 at 09:56:49AM +0900, Michael Paquier wrote:
>> On Wed, May 16, 2018 at 08:20:49PM -0400, Bruce Momjian wrote:
>>> SCRAM-with-binding is the first password method that attempts to avoid
>>> man-in-the-middle attacks, and therefore is much less likely to be able
>>> to trust what the endpoints supports.  I think it is really the
>>> channel_binding_mode that we want to control at the client.  The lesser
>>> modes are much more reasonable to use an automatic best-supported
>>> negotiation, which is what we do now.
>>
>> Noted.  Which means that the parameter is ignored when using a non-SSL
>> connection, as well as when the server tries to enforce the use of
>> anything else than SCRAM.
>
> Uh, a man-in-the-middle could prevent SSL or ask for a different
> password authentication method and then channel binding would not be
> used.  I think when you say you want channel binding, you have to fail
> if you don't get it.

I am not exactly sure what is the result we are looking for here, so I
am adding for now an open item which refers to this part of the thread.
Please note that I am fine to spend cycles if needed to address any
issues and/or concerns.  Let's the discussion continue for now.
--
Michael