Horton

Re: pg_authid.rolpassword format (was Re: Password identifiers, protocol aging and SCRAM protocol)

Peter Eisentraut <peter.eisentraut@2ndquadrant.com>

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From: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
To: Heikki Linnakangas <hlinnaka@iki.fi>, Michael Paquier <michael.paquier@gmail.com>
Cc: Magnus Hagander <magnus@hagander.net>, Robert Haas <robertmhaas@gmail.com>, Andres Freund <andres@anarazel.de>, David Steele <david@pgmasters.net>, Tom Lane <tgl@sss.pgh.pa.us>, David Fetter <david@fetter.org>, Alvaro Herrera <alvherre@2ndquadrant.com>, Julian Markwort <julian.markwort@uni-muenster.de>, Stephen Frost <sfrost@snowman.net>, PostgreSQL mailing lists <pgsql-hackers@postgresql.org>, Valery Popov <v.popov@postgrespro.ru>
Date: 2017-01-17T21:51:10Z
Lists: pgsql-hackers 
On 1/3/17 9:09 AM, Heikki Linnakangas wrote:
> Since not everyone agrees with this approach, I split this patch into 
> two. The first patch refactors things, replacing the isMD5() function 
> with get_password_type(), without changing the representation of 
> pg_authid.rolpassword. That is hopefully uncontroversial.

I have checked these patches.

The refactoring in the first patch seems sensible.  As Michael pointed
out, there is still a reference to "plain:" in the first patch.

The commit message needs to be updated, because the function
plain_crypt_verify() was already added in a previous patch.

I'm not fond of this kind of coding

    password = encrypt_password(password_type, stmt->role, password);

where the 'password' variable has a different meaning before and after.

This error message might be a mistake:

    elog(ERROR, "unrecognized password type conversion");

I think some pieces from the second patch could be included in the first
patch, e.g., the parts for passwordcheck.c and user.c.

> And the second 
> patch adds the "plain:" prefix, which not everyone agrees on.

The code also gets a little bit dubious, as it introduces an "unknown"
password type, which is sometimes treated as plaintext and sometimes as
an error.  I think this is going be messy.

I would skip this patch for now at least.  Too much controversy, and we
don't know how the rest of the patches for this feature will look like
to be able to know if it's worth it.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

Commits

  1. Support SCRAM-SHA-256 authentication (RFC 5802 and 7677).

  2. Refactor SHA2 functions and move them to src/common/.

  3. Replace isMD5() with a more future-proof way to check if pw is encrypted.

  4. Remove bogus notice that older clients might not work with MD5 passwords.

  5. Refactor the code for verifying user's password.

  6. Replace PostmasterRandom() with a stronger source, second attempt.

  7. Remove support for (insecure) crypt authentication.