Horton

Re: Password identifiers, protocol aging and SCRAM protocol

Michael Paquier <michael.paquier@gmail.com>

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From: Michael Paquier <michael.paquier@gmail.com>
To: Victor Wagner <vitus@wagner.pp.ru>
Cc: PostgreSQL mailing lists <pgsql-hackers@postgresql.org>
Date: 2016-11-09T06:23:11Z
Lists: pgsql-hackers 
On Wed, Nov 9, 2016 at 3:13 PM, Victor Wagner <vitus@wagner.pp.ru> wrote:
> On Tue, 18 Oct 2016 16:35:27 +0900
> Michael Paquier <michael.paquier@gmail.com> wrote:
>
>  Hi
>> Attached is a rebased patch set for SCRAM, with the following things:
>> - 0001, moving all the SHA2 functions to src/common/ and introducing a
>> PG-like interface. No actual changes here.
>
> It seems, that client nonce generation in this patch is not
> RFC-compliant.
>
> RFC 5802 states that SCRAM nonce should be
>
> a sequence of random printable ASCII
>       characters excluding ','
>
> while this patch uses sequence of random bytes from pg_strong_random
> function with zero byte appended.

(This is about patch 0007, not 0001)
Thanks, you are right. That's not good as-is. So this basically means
that the characters here should be from 32 to 127 included.
generate_nonce needs just to be made smarter in the way it selects the
character bytes.
-- 
Michael

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.