[EdLUG] Lubuntu 14.04 guest session login failure

Sun Jul 9 18:43:14 UTC 2017

Thanks very much!!

On Sun, Jul 9, 2017 at 3:49 AM, Edinburgh Linux Users Group <
edlug at lists.edlug.org.uk> wrote:

> I had this recently and was puzzled for 3 days. Eventually worked out that
> .Xauthority was owned by root, so simply deleted the file!
>
> Andrew Smith B.Sc(Hons), MBA
>
> T:01383-411351
> M: 0772-456-3636
> E: asmith9983 at gmail.com
>
> On 9 July 2017 at 04:15, Edinburgh Linux Users Group <
> edlug at lists.edlug.org.uk> wrote:
>
>> Hi, a volunteer with higher sys admin skills came by the low income
>> shelter today and diagnosed a solution to the guest session login failure
>> loop.  Here is what she wrote:
>>
>> In case anyone was curious as to what happened with this, I finally
>> had some time to sit down on site this evening and do some debugging.
>>
>> Some background as to how the guest logins work in Lubuntu: A
>> guest-XXXXX (random characters) user is created upon login, which is
>> used throughout the session. It is then deleted when the user logs
>> out.
>>
>> After some red herrings in the auth logs (mostly PAM errors around KDE
>> and Gnome keyrings), I did some digging in the lightdm logs.
>> Eventually I noticed the UID of the guest account trying to be created
>> was the same every time a login attempt was made: 999. Odd. So I
>> looked in /etc/passwd and noticed that there were hundreds of
>> guest-XXXXX accounts. That's no good!
>>
>> Turns out, at some point the /etc/subgid.lock file got stuck in an
>> existing state (wasn't deleted when the lock concluded), which meant
>> the command to delete the user was not completing successfully upon
>> logout. Users were piling up and never being deleted. Once the UIDs
>> hit 999 it was failing to create new guest users, so the login would
>> fail. A quick mv (rm didn't work) of the subgid.lock file and a script
>> to delete all the guest accounts got us going again.
>>
>> I'm considering my options to get us out of this reoccurring issue in
>> the future. I'm thinking of just a cron job on each machine that
>> checks for a subgid.lock file sticking around for more than a couple
>> days and moving it out of the way, but I'll sleep on it. More clever
>> suggestions welcome ;)
>>
>> Thanks for everyone who tried to help.  Any suggestions are welcome!
>>
>> On Sat, Jul 8, 2017 at 5:03 PM, Edinburgh Linux Users Group <
>> edlug at lists.edlug.org.uk> wrote:
>>
>>> Hi,
>>>
>>> I don't see how a guest could be causing this issue.  We are
>>> experiencing this guest session login failure loop on several machines at
>>> several difference low income shelters.  We are still stymied.  Someone
>>> suggested that removing appamor would work, but it didn't.
>>>
>>> On Tue, Apr 4, 2017 at 1:33 AM, Edinburgh Linux Users Group <
>>> edlug at lists.edlug.org.uk> wrote:
>>>
>>>> Hi Christian
>>>>
>>>> Are you saying that this problem occurs on one machine only? Could it
>>>> be that a "guest" has tried to make changes to the guest login and has
>>>> broken something?
>>>>
>>>> If these machines are all standard installs, would it be simpler to
>>>> reinstall instead of trying to solve a mysterious problem? If reinstalling
>>>> seems too much work (if there are a lot of customisations) I suggest making
>>>> an image backup (from one of the working machines) and restore (may be
>>>> handy to keep an image backup for this purpose anyway)
>>>>
>>>> Let us know how you get on.
>>>>
>>>> Regards
>>>> Geetam
>>>>
>>>> ---
>>>> I don't know
>>>> ...
>>>> I don't know what it is
>>>> ...
>>>> I don't know what it is that I don't know
>>>>
>>>> Isn't it beautiful
>>>>
>>>> On 4 April 2017 07:19:28 Edinburgh Linux Users Group <
>>>> edlug at lists.edlug.org.uk> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> I am experiencing a very strange thing for which there are no ready
>>>>> answers by googling.  I am a volunteer for a non-profit which puts
>>>>> GNU-Linux computers in low income shelters.  They are stand-alone machines
>>>>> connected directly to the Internet via a hub on a dedicated ethernet cable.
>>>>>
>>>>> The shelters don't want the users to be able to store anything
>>>>> directly to the machine's hard drive.  To give them that functionality, we
>>>>> ask them to use the guest session, which wipes out all data by default when
>>>>> the session ends.
>>>>>
>>>>> Right now, however, we are experiencing a failure of logging into the
>>>>> guest session.  Normally, you just choose the guest session in the Lubuntu
>>>>> login screen, and hit enter, and it boots up a full guest session.  No
>>>>> password is required.
>>>>>
>>>>> Now, when I chose the guest session and hit enter, the system appears
>>>>> to head toward a normal login, but then quickly fails and returns to the
>>>>> login screen.
>>>>>
>>>>> The system's SU admin account is performing normally.  To get into the
>>>>> admin account, I just choose it in the login screen, enter the password,
>>>>> and the admin session boots up normally.
>>>>>
>>>>> This whole thing is very strange, and I have never seen anything like
>>>>> it before.  We are using 14.04 on 13 machines with identical or similar
>>>>> hardware and are not having any such problems.  This email is being written
>>>>> on one of those such machines, and the guest session works just fine.
>>>>>
>>>>> I ran updates on the malfunctioning machines, rebooted, no joy.
>>>>>
>>>>> Thanks very much in advance.
>>>>>
>>>>> --
>>>>> Christian Einfeldt
>>>>> _______________________________________________
>>>>> EdLUG mailing list
>>>>> EdLUG at lists.edlug.org.uk
>>>>> https://lists.edlug.org.uk/mailman/listinfo/edlug
>>>>>
>>>>
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>>>>
>>>
>>>
>>> --
>>> Christian Einfeldt
>>>
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>>
>>
>>
>> --
>> Christian Einfeldt
>>
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>
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-- 
Christian Einfeldt
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