X2Go Bug report logs - #1258
x2goclient hangs when connecting with Kerberos auth

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Package: x2goclient; Maintainer for x2goclient is X2Go Developers <x2go-dev@lists.x2go.org>; Source for x2goclient is src:x2goclient.

Reported by: Mike DePaulo <mikedep333@gmail.com>

Date: Mon, 19 Feb 2018 04:30:02 UTC

Severity: normal

Tags: pending

Found in version

Fixed in version

Done: X2Go Release Manager X2Go Release Manager <git-admin@x2go.org>

Bug is archived. No further changes may be made.

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From: owner@bugs.x2go.org (X2Go Bug Tracking System)
Subject: Bug#1258 closed by Mike DePaulo Mike DePaulo <mikedep333@gmail.com>
 (X2Go issue (in src:x2goclient) has been marked as closed)
Message-ID: <handler.1258.c.151990743310010.notifdone@bugs.x2go.org>
References: <20180301123016.BD2F25DAE9@ymir.das-netzwerkteam.de>
X-X2go-PR-Keywords: pending
X-X2go-PR-Message: they-closed 1258
X-X2go-PR-Package: x2goclient
X-X2go-PR-Source: x2goclient
Date: Thu, 01 Mar 2018 12:35:02 +0000
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[Message part 1 (text/plain, inline)]
This is an automatic notification regarding your Bug report
which was filed against the x2goclient package:

#1258: x2goclient hangs when connecting with Kerberos auth

It has been closed by Mike DePaulo Mike DePaulo <mikedep333@gmail.com>.

Their explanation is attached below along with your original report.
If this explanation is unsatisfactory and you have not received a
better one in a separate message then please contact Mike DePaulo Mike DePaulo <mikedep333@gmail.com> by
replying to this email.

X2Go Bug Tracking System
Contact owner@bugs.x2go.org with problems
[Message part 2 (message/rfc822, inline)]
From: Mike DePaulo Mike DePaulo <mikedep333@gmail.com>
To: 1258-submitter@bugs.x2go.org
Cc: control@bugs.x2go.org, 1258@bugs.x2go.org
Subject: X2Go issue (in src:x2goclient) has been marked as closed
Date: Thu, 1 Mar 2018 13:30:16 +0100 (CET)
close #1258


we are very hopeful that X2Go issue #1258 reported by you
has been resolved in the new release ( of the
X2Go source project »src:x2goclient«.

You can view the complete changelog entry of src:x2goclient (
below, and you can use the following link to view all the code changes
between this and the last release of src:x2goclient.


If you feel that the issue has not been resolved satisfyingly, feel
free to reopen this bug report or submit a follow-up report with
further observations described based on the new released version
of src:x2goclient.

Thanks a lot for contributing to X2Go!!!

X2Go Git Admin (on behalf of the sender of this mail)

X2Go Component: src:x2goclient
Date: Wed, 28 Feb 2018 20:53:41 -0500
Fixes: 1258
 x2goclient ( RELEASED; urgency=medium
   [ Mike DePaulo ]
   * New upstream version (
     - src/sshmasterconnection.cpp: Do not attempt to perform Interaction with
       SSH Server (e.g. for changing expired password) when using
       GSSAPI/Kerberos because the interaction code does not support it yet.
       Fixes: #1258
     - Windows: Update PuTTY from 0.68 to 0.70, which fixes PuTTY vulns
       vuln-indirect-dll-hijack-2 & vuln-indirect-dll-hijack-3.
       Note that x2goclient was only ever affected if the permissions on the
       installation folder were changed to give users write access, or if
       x2goclient was copied/extracted to a folder where users could write.

[Message part 3 (message/rfc822, inline)]
From: Mike DePaulo <mikedep333@gmail.com>
To: submit@bugs.x2go.org
Subject: x2goclient hangs when connecting with Kerberos auth
Date: Sun, 18 Feb 2018 23:28:12 -0500
Package: x2goclient

When attempting to connect to an X2Go server with GSSAPI/Kerberos
auth, x2goclient hangs indefinitely.

This was observed with nightly builds for Windows, and was assumed to
be Windows-specific.

The fix has already been committed to master. I will update master
with another commit (& change to debian/changelog) stating that this
was fixed:
commit 7cbd8d525309edb8bd05d27ec57ac72e2d8c90e8
Author: Mike DePaulo <mikedep333@gmail.com>
Date:   Sun Feb 18 19:52:22 2018 -0500

    Do not attempt to perform Interaction with SSH Server

    (e.g. for changing expired password) when using GSSAPI/Kerberos
    because the interaction code does not support it yet.

But as I was fixing it, I noticed that Linux & Mac OS X are probably
affected too.

The cause of the issue is that the new Interaction Dialog feature
introduced by this commit contains libssh-specific function calls, but
we use PuTTY binaries on Windows & the OpenSSH ssh client binary on
Linux/MacOS for GSSAPI/Kerberos:
commit 68bbf328132125eaad5c53b0ac82490bf818e42e
Author: Oleksandr Shneyder <o.shneyder@phoca-gmbh.de>
Date:   Wed May 10 15:22:11 2017 +0200

    Interaction with SSH server (for example for changing expired
password). Fixes: #592.

And the "fix" for this is to bypass that new feature when
GSSAPI/Kerberos auth is used.

I will open up a separate issue about the fact that the Interaction
Dialog feature does not work with GSSAPI/Kerberos.


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