Re: Raising the SCRAM iteration count

On Sun, Dec 11, 2022 at 12:46:23AM +0100, Daniel Gustafsson wrote:
> SCRAM with an iteration count of 1 still provides a lot of benefits over md5,
> so if we can make those comparable in performance then that could be a way
> forward (with the tradeoffs properly documented).

Okay, it looks like there is a wish to make that configurable anyway,
and I have a few comments about that.

{"scram_iteration_count", PGC_SUSET, CONN_AUTH_AUTH,
+ gettext_noop("Sets the iteration count for SCRAM secret generation."),
+ NULL,
+ GUC_NOT_IN_SAMPLE | GUC_SUPERUSER_ONLY
+ },

Shouldn't this be user-settable as a PGC_USERSET rather than
PGC_SUSET which would limit its updates to superusers?

As shaped, the GUC would not benefit to \password, and we should not
encourage users to give a raw password over the wire if possible if
they wish to compute a verifier with a given interation number.
Hence, wouldn't it be better to mark it as GUC_REPORT, and store its
status in pg_conn(at)libpq-int(dot)h in the same fashion as
default_transaction_read_only and hot_standby? This way,
PQencryptPasswordConn() would be able to feed on it automatically
rather than always assume the default implied by
pg_fe_scram_build_secret().
--
Michael