From owner-freebsd-security@FreeBSD.ORG  Fri Aug 30 13:12:51 2013
Return-Path: <owner-freebsd-security@FreeBSD.ORG>
Delivered-To: freebsd-security@FreeBSD.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTP id 9D747E39
 for <freebsd-security@FreeBSD.org>; Fri, 30 Aug 2013 13:12:51 +0000 (UTC)
 (envelope-from slw@zxy.spb.ru)
Received: from zxy.spb.ru (zxy.spb.ru [195.70.199.98])
 by mx1.freebsd.org (Postfix) with ESMTP id 570EB2378
 for <freebsd-security@FreeBSD.org>; Fri, 30 Aug 2013 13:12:51 +0000 (UTC)
Received: from slw by zxy.spb.ru with local (Exim 4.69 (FreeBSD))
 (envelope-from <slw@zxy.spb.ru>)
 id 1VFOXP-0002Hm-St; Fri, 30 Aug 2013 17:14:55 +0400
Date: Fri, 30 Aug 2013 17:14:55 +0400
From: Slawa Olhovchenkov <slw@zxy.spb.ru>
To: Dag-Erling Sm??rgrav <des@des.no>
Subject: Re: OpenSSH, PAM and kerberos
Message-ID: <20130830131455.GW3796@zxy.spb.ru>
References: <20130829004844.GA70584@zxy.spb.ru> <86d2ovy64p.fsf@nine.des.no>
 <20130830100926.GU3796@zxy.spb.ru>
 <20130830103009.GV3796@zxy.spb.ru> <86sixrwdcv.fsf@nine.des.no>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <86sixrwdcv.fsf@nine.des.no>
User-Agent: Mutt/1.5.21 (2010-09-15)
X-SA-Exim-Connect-IP: <locally generated>
X-SA-Exim-Mail-From: slw@zxy.spb.ru
X-SA-Exim-Scanned: No (on zxy.spb.ru); SAEximRunCond expanded to false
Cc: freebsd-security@FreeBSD.org
X-BeenThere: freebsd-security@freebsd.org
X-Mailman-Version: 2.1.14
Precedence: list
List-Id: "Security issues \[members-only posting\]"
 <freebsd-security.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-security>, 
 <mailto:freebsd-security-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-security>
List-Post: <mailto:freebsd-security@freebsd.org>
List-Help: <mailto:freebsd-security-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-security>, 
 <mailto:freebsd-security-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Fri, 30 Aug 2013 13:12:51 -0000

On Fri, Aug 30, 2013 at 02:51:44PM +0200, Dag-Erling Sm??rgrav wrote:

> Slawa Olhovchenkov <slw@zxy.spb.ru> writes:
> > Dag-Erling Sm??rgrav <des@des.no> writes:
> > > PAM authentication in OpenSSH was broken for non-trivial cases when
> > > privilege separation was implemented.  Fixing it properly would be
> > > very difficult.
> > Same behaviour with 'UsePrivilegeSeparation no'.  This issuse not in
> > privilege separation, this is because PAM authentication use pthread
> > emulation throw fork().
> 
> Please don't tell me how the code works.  I wrote it - or rather, I
> wrote a version that worked, before the OpenSSH developers implemented
> privilege separation and had to break the PAM integration code to make
> it fit.  Even if you #define UNSUPPORTED_POSIX_THREADS_HACK to use
> threads instead of a subprocess, OpenSSH will still call pam_start()
> twice and lose the data stored in the authentication phase before
> running the session phase.

Hmmm, now I try to compile sshd with UNSUPPORTED_POSIX_THREADS_HACK and
it works (/tmp/krb5cc_NNNN created, kerberosied login to other host
working w/o entering password). 

And I see only one record in log file (debug1: PAM: initializing for "slw")

What I missed?

PS: UsePrivilegeSeparation yes


> (this is technically an abuse of the PAM API; I should probably add a
> few lines to the OpenPAM dispatcher so it logs an error every time an
> application tries to open a session without first authenticating)
> 
> DES
> -- 
> Dag-Erling Sm??rgrav - des@des.no