[X2Go-Dev] X2Go Client - new features and bugfix

Mon Dec 16 15:50:23 CET 2013

Alex,

As always, thank you for your contribution.

However, now GSSAPI authentication appears to no longer work at all on windows.

If I do connect a to machine via GSSAPI (or to a machine via password
but with a GSSAPI proxy, or to a machine via GSSAPI via a GSSAPI
proxy), the x2go client window stays open and the X server (VcXsrv)
never appears.

This bug only seems to happen if GSSAPI auth succeeds. If I purposely
misconfigure the x2goserver's kerberos (e.g., I run samba's "net -P
ads keytab flush" command to clear the contents of /etc/krb5.keytab),
I instead get the erorr message "Check your GSSapi configuration or
choose another authentication method."

I am prompted to accept the ssh host id before this happens (if it was
not already accepted.)

When this happens, I can close X2Go Client by clicking the X . Other
than that and unless I am reconnecting (see the next line), the x2go
client window is frozen.

If I close x2go client and reconnect, I am prompted to resume (or
suspend/terminate) the session. However, I cannot resume the session
because the x2go client freezes like before.

"Show details" never shows any output when this happens.

vcxsrv does appear to be running in the background when this happens.

I tested this on two windows 8.1 64-bit physical machines.

I uploaded this win32 build to the x2go server (accessible only to
devs) under /home/x2go/test-of-6290a9f307423210fdb7f8f08f2eb9c52e5ad551/

-Mike

On Mon, Dec 16, 2013 at 5:28 AM, Oleksandr Shneyder
<o.shneyder at phoca-gmbh.de> wrote:
> Hello Mike,
>
> please test if commit
> http://code.x2go.org/gitweb?p=x2goclient.git;a=commit;h=6290a9f307423210fdb7f8f08f2eb9c52e5ad551
> fixed issue you have described.
>
> regards,
> Alex
>
> Am 14.12.2013 03:47, schrieb Michael DePaulo:
>> Alex,
>>
>> Your patch successfully fixed the problem of X2goClient crashing when
>> a username is not entered. Good job on that.
>>
>> And I tested it on my Windows XP SP3 32-bit VM (in addition to my
>> desktop with Win 8.1 64-bit), the GSSAPI / Kerberos auth works there
>> too.
>>
>> However, I still managed to produce one more crash on Windows, albeit
>> an obscure one.
>>
>> If GSSAPI authentication is enabled, and you connect through an SSH
>> proxy, that SSH proxy must also use GSSAPI. It prompts you for a
>> password, but it seems to ignore it. I've entered an incorrect
>> password and still connects. This is not that bad of a bug and I think
>> we can launch 4.0.1.2 despite it.
>>
>> If that proxy does successfully authenticate using GSSAPI, and you
>> successfully connect to the x2goserver via GSSAPI, the session opens
>> and works as far as I've tested it. However, on disconnect, the
>> x2goclient crashes.
>>
>> I do not know if this crash would be realistically produced. After
>> all, if the entire point of the proxy is to connect through a
>> firewall, would you really be using Kerberos auth to both the proxy
>> and the x2goserver? I do not think this crash bug has to be fixed
>> before 4.0.1.2, but I thought I'd mention it and the former bug. (I
>> will put them in the bug tracker if we do launch with these bugs.)
>>
>> -Mike
>>
>> On Fri, Dec 13, 2013 at 10:57 AM, Michael DePaulo <mikedep333 at gmail.com> wrote:
>>> I will test it when I get home in about 7 hours. I will not be able to build
>>> until then also.
>>>
>>> FYI, if you leave the username blank when using password auth, x2goclient
>>> prompts you for both the username and password. That's why the username
>>> field is likely left blank.
>>>
>>> Regards,
>>> Mike
>>>
>>> On Dec 13, 2013 9:57 AM, "Oleksandr Shneyder" <o.shneyder at phoca-gmbh.de>
>>> wrote:
>>>>
>>>> Hi Mike,
>>>>
>>>> I newer sought, that some one will try to open connection without
>>>> specifying a username. But ok, this patch make x2go client to use
>>>> default user name if no username is specified.
>>>>
>>>>
>>>> http://code.x2go.org/gitweb?p=x2goclient.git;a=commit;h=b69329589121f2476a111622ec1cc34b12b5c112
>>>>
>>>> regards,
>>>> Alex
>>>>
>>>>
>>>> Am 13.12.2013 14:59, schrieb Michael DePaulo:
>>>>> On Fri, Dec 13, 2013 at 7:07 AM, Oleksandr Shneyder
>>>>> <o.shneyder at phoca-gmbh.de> wrote:
>>>>>> Hello Mike,
>>>>>>
>>>>>> this patch:
>>>>>>
>>>>>>
>>>>>> http://code.x2go.org/gitweb?p=x2goclient.git;a=commitdiff;h=6f9ead7cf9184799f0b6ae9ff1efd0c7b879d0c6
>>>>>>
>>>>>> should fix the issue.
>>>>>>
>>>>>> regards,
>>>>>> Alex
>>>>>>
>>>>>
>>>>> Hi Alex,
>>>>>
>>>>> That appears to partially fix the issue.
>>>>>
>>>>> When I enter an invalid username (e.g. "a"), I get the error message
>>>>> "Check your GSSApi configuration or choose another authentication
>>>>> method". So that's a good improvement.
>>>>>
>>>>> But if the username field is left blank, the x2goclient still crashes.
>>>>>
>>>>> regards,
>>>>> -Mike
>>>>> _______________________________________________
>>>>> X2Go-Dev mailing list
>>>>> X2Go-Dev at lists.berlios.de
>>>>> https://lists.berlios.de/mailman/listinfo/x2go-dev
>>>>>
>>>>
>>>>
>>>> --
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>>>> Oleksandr Shneyder  | Email: o.shneyder at phoca-gmbh.de
>>>> phoca GmbH          | Tel. : 0911 - 14870374 0
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>>>>
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>
>
> --
> ----------------------------------------------------
> Oleksandr Shneyder  | Email: o.shneyder at phoca-gmbh.de
> phoca GmbH          | Tel. : 0911 - 14870374 0
> Bräuhausgasse 9     | Fax. : 0911 - 14870374 9
> D-82205 Gilching    | Mobil: 0163 - 49 64 461
>
> Geschäftsführung:
> Dipl.-Inf. Oleksandr Shneyder
>
> Amtsgericht München | http://www.phoca-gmbh.de
> HRB 196 658         | http://www.x2go.org
> USt-IdNr.: DE281977973
> ----------------------------------------------------
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