Re: SCRAM with channel binding downgrade attack - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: SCRAM with channel binding downgrade attack
Date
Msg-id 20180518133022.GD3088@momjian.us
Whole thread Raw
In response to Re: SCRAM with channel binding downgrade attack  (Michael Paquier <michael@paquier.xyz>)
Responses Re: SCRAM with channel binding downgrade attack  (Michael Paquier <michael@paquier.xyz>)
List pgsql-hackers
On Fri, May 18, 2018 at 12:03:49PM +0900, Michael Paquier wrote:
> On Fri, May 18, 2018 at 10:46:46AM +0900, Michael Paquier wrote:
> > From a security point of view, 1) is important for libpq, but I am not
> > much enthusiast about 2) as a whole.  The backend has proper support for
> > channel binding, hence other drivers speaking the protocol could have
> > their own restriction mechanisms.
> 
> So, I have been playing with libpq to address point 1), and added a new
> connection parameter called channel_binding_mode which can be set to
> 'prefer', which is what libpq uses now, and 'require'.  The patch has
> two important parts:

Good work, but I think the existance of both scram_channel_binding and
channel_binding_mode in libpq is confusing.  I am thinking we should
have one channel binding parameter that can take values "prefer",
"tls-unique", "tls-server-end-point", and "require".  I don't see the
point to having "none" and "allow" that sslmode supports.   "tls-unique"
and "tls-server-end-point" would _require_ those channel binding modes; 
the setting would never be ignored, e.g. if no SSL.

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

+ As you are, so once was I.  As I am, so you will be. +
+                      Ancient Roman grave inscription +


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