From: Damien Miller (djmcvs.openbsd.org)
Date: Wed Jul 02 2008 - 07:36:39 CDT

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CVSROOT: /cvs
Module name: src
Changes by: djmcvs.openbsd.org 2008/07/02 06:36:39

Modified files:
        usr.bin/ssh : auth2.c auth2-none.c

Log message:
Make protocol 2 MaxAuthTries behaviour a little more sensible:

Check whether client has exceeded MaxAuthTries before running
an authentication method and skip it if they have, previously it
would always allow one try (for "none" auth).

Preincrement failure count before post-auth test - previously this
checked and postincremented, also to allow one "none" try.

Together, these two changes always count the "none" auth method
which could be skipped by a malicious client (e.g. an SSH worm)
to get an extra attempt at a real auth method. They also make
MaxAuthTries=0 a useful way to block users entirely (esp. in a
sshd_config Match block).

Also, move sending of any preauth banner from "none" auth method
to the first call to input_userauth_request(), so worms that skip
the "none" method get to see it too.

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