Horton

Re: Password identifiers, protocol aging and SCRAM protocol

Heikki Linnakangas <hlinnaka@iki.fi>

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From: Heikki Linnakangas <hlinnaka@iki.fi>
To: Michael Paquier <michael.paquier@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Andres Freund <andres@anarazel.de>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, David Steele <david@pgmasters.net>, Tom Lane <tgl@sss.pgh.pa.us>, David Fetter <david@fetter.org>, Alvaro Herrera <alvherre@2ndquadrant.com>, Magnus Hagander <magnus@hagander.net>, 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: 2016-12-09T09:51:45Z
Lists: pgsql-hackers

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On 12/09/2016 05:58 AM, Michael Paquier wrote:
>
> One thing is: when do we look up at pg_authid? After receiving the
> first message from client or before beginning the exchange? As the
> first message from client has the user name, it would make sense to do
> the lookup after receiving it, but from PG prospective it would just
> make sense to use the data already present in the startup packet. The
> current patch does the latter. What do you think?

While hacking on this, I came up with the attached refactoring, against 
current master. I think it makes the current code more readable, anyway, 
and it provides a get_role_password() function that SCRAM can use, to 
look up the stored password. (This is essentially the same refactoring 
that was included in the SCRAM patch set, that introduced the 
get_role_details() function.)

Barring objections, I'll go ahead and commit this first.

- Heikki

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.