Subject: Re: Password identifiers, protocol aging and SCRAM protocol
To: Michael Paquier <michael.paquier@gmail.com>
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From: David Steele <david@pgmasters.net>
Message-ID: <56E848A9.1070203@pgmasters.net>
Date: Tue, 15 Mar 2016 13:38:49 -0400
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Hi Michael,

On 3/14/16 7:07 PM, Michael Paquier wrote:

> On Mon, Mar 14, 2016 at 5:06 PM, Michael Paquier <michael.paquier@gmail.com> wrote:
>
>> On Mon, Mar 14, 2016 at 4:32 PM, David Steele <david@pgmasters.net> wrote:
>>
>>> Could you provide an updated set of patches for review?  Meanwhile I am
>>> marking this as "waiting for author".
>>
>> Sure. I'll provide them shortly with all the comments addressed. Up to
>> now I just had a couple of comments about docs and whitespaces, so I
>> didn't really bother sending a new set, but this meritates a rebase.
> 
> And here they are. I have addressed the documentation and the
> whitespaces reported up to now at the same time.

For this first review I would like to focus on the user visible changes
introduced in 0001-0002.

First I created two new users with each type of supported verifier:

postgres=# create user test with password 'test';
CREATE ROLE
postgres=# create user testu with unencrypted password 'testu'
           valid until '2017-01-01';
CREATE ROLE

1) I see that rolvaliduntil is still in pg_authid:

postgres=# select oid, rolname, rolvaliduntil from pg_authid;

  oid  | rolname |     rolvaliduntil
-------+---------+------------------------
    10 | vagrant |
 16387 | test    |
 16388 | testu   | 2017-01-01 00:00:00+00

I think that's OK if we now define it to be "role validity" (it's still
password validity in the patched docs).  I would also like to see a
validuntil column in pg_auth_verifiers so we can track password
expiration for each verifier separately.  For now I think it's enough to
copy the same validity both places since there can only be one verifier.

2) I don't think the column naming in pg_auth_verifiers is consistent
with other catalogs:

postgres=# select * from pg_auth_verifiers;

 roleid | verimet |               verival
--------+---------+-------------------------------------
  16387 | m       | md505a671c66aefea124cc08b76ea6d30bb
  16388 | p       | testu

System catalogs generally use a 3 character prefix so I would expect the
columns to be (if we pick avr as a prefix):

avrrole
avrmethod
avrverifier
avrvaliduntil

I'm not a big fan in abbreviating too much so you can see I've expanded
the names a bit.

3) rolpassword is still in pg_shadow even though it is not useful anymore:

postgres=# select usename, passwd, valuntil from pg_shadow;

 usename |  passwd  |        valuntil
---------+----------+------------------------
 vagrant | ******** |
 test    | ******** |
 testu   | ******** | 2017-01-01 00:00:00+00

If anyone is actually using this column in a meaningful way they are in
for a nasty surprise when trying use the value in passwd as a verifier.
 I would prefer to drop the column entirely and produce a clear error.

Perhaps a better option would be to drop pg_shadow entirely since it
seems to have no further purpose in life.

Thanks,
-- 
-David
david@pgmasters.net


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