Blocked at gdm login screen on 18.04 if user password has a circumflex accent

[Xavier Guillot]

Hi,

I have a bug since the recent updates on Ubuntu 18.04 (post 10th March): when the user password contains a circumflex accent, like "û", access is denied even if password entered is correct and I stay blocked in a loop at gdm login screen - error message (translated from French): "Sorry, it doesn't work, please try again".

Even after modifying it on recovery mode with passwd without û, it stays blocked. Only way to solve it is to reinstall.

Graphic card: [AMD/ATI] Cape Verde XT [Radeon HD 7770/8760 / R7 250X]
Kernel driver in use: radeon
Kernel modules: radeon, amdgpu

Steps to reproduce :

I did a fresh and new install with 18.04 daily iso from 21st March, formatting / and /home with following user password:

Ubuntu42

At startup, I could log successfully both on Xorg and Wayland sessions. Then I modified and tested those passwords, with all of them I could again boot and connect, on Xorg and Wayland:
ArchLinux43
LinuxMint@28
KDENeon=51
Fedora_1984

But the last one made me blocked at the gdm login screen:

Debianû74

Here unable to modify it on recovery session, error message in French: "erreur de manipulation du jeton d'authentification".

Also unable to launch terminal: CTRl Alt F1 refreshes the screen, but F2, F3... F12 freezes it! I only can update in chroot with lie USB.

I had to again format and reinstall, with a password without any circumflex accent.

How and when I discovered it :

On 10th March, I ran since many weeks the alpha version of Ubuntu 18.04, with a password having a "û" inside, which had always worked fine. I did an update, cumulating the last 3 weeks before.

On next startup, when I typed my password, both on Xorg and Wayland sessions, no error message but no desktop, nothing appeared but a few seconds later I was back on login screen.

I could well log in on terminal (Ctrl Alt F2) or chroot with a live USB, and do the last updates in the next days, but nothing changed.

On console, if I ran "startx" I got the message "timeout in locking authority file" and "fatal server error: cannot open log file ./local/share/xorg/Xorg.0.log

Both / and /home were not full - more than 60% space available, verified with df -Th ; echo ; df -Ti

I tried to reinstall Ubuntu with daily live of 15th March, formatting / but not /home as it was protected by ecryptfs and I didn't save some files, using same user name and password, still blocked.

So I copied the /home and .Private folders to another disk to try later recover them, reinstall again, formatting both / and /home, always with my usual password having a "û" (I verified French language, keyboard with French activated, upper case, symbols... OK).

This time, again both for Xorg or Wayland sessions, at gdm login I did not success to connect, I got an error message "Désolé ça n'a pas fonctionné, veuillez réessayer",

I tried to modify the password in recovery mode, with no special characters nor accents, but still blocked at gdm. And no terminal available with Ctrl Alt F2...

On 23rd March, I re-reinstalled all Ubuntu, formatting / and /home, this time with daily iso from 21st March, but with a modification: to avoid any misconfiguration with languages on live USB, I chose a very easy password, only with normal letters and numbers.

On startup, yes, finally I could log at gdm on default Xorg session and enter desktop !

I went to my user configuration, changed to put my usual password (with an "û"), and bam, back to the future, still blocked at gdm screen on restart, either on Xorg or Wayland, Ctr Alt F2 not working.

It made me understand that the bug came from a special character in my password, then I tried the different ones explained on top of this report to discover it was "û".

[Daniel van Vugt (vanvugt)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This particular bug has already been reported and is a duplicate of bug 1716159, so it is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Feel free to continue to report any other bugs you may find.

[Xavier Guillot (valeryan-24)]

Hi, I'm not sure this is an exact duplicte of bug 1716159 (I saw it before reporting here). It's right, today I checked, if I enter û in the gdm login field, it writes u, but :

- this was also the case since early alpha testing of Ubuntu 17.10, I already had the same password, only since update of 10th March 2018 it is refused. And when I chose it, on the live USB installation, was the French alternative keyboard selected, so I'm sure it was with the accent (I checked again, typing one with û and one with u gets an error on 2 passwords not matching).

- In this case, modifying the password in recovery session should have allowed me to login again (which I could in terminal only the very first time I had this bug, so modification was successful, after ,I have no access to console), but not...

Something specifically changed between mid-February and 10th March making login impossible with my "û" containing password and forcing me to reinstall...

[Daniel van Vugt (vanvugt)]

I have just documented a possible workaround in bug 1716159. Please try that.

[Xavier Guillot (valeryan-24)]

Thanks, I already did that the first time I was blocked on login screen, it failed at step 3 : unable to connect after changing passwd in recovery...

I don't know if problem is correlated, but I have no more access to terminal : Ctrl Alt F1 F2... does nothing.

For the moment I solved the problem with a complete fresh reinstallation of Ubuntu bionic, iso from 21st March and an initial password without "û".

But someone just tried with Debian Stretch, gdm3 version 3.22.3 : when he writes û in the login field, it well writes û with the accent.

In 18.04, when I type û, it writes u

I need to test on Ubuntu Artful, but as said before my password always had û on 17.10 and it worked, same on early versions of 18.04 ; only with the 10th March updates of bionic it failed, with gdm3 now in 3.27.92.

For me it is a different bug than 1716159 because much more recent, at least for the circumflex accent problem.

[Daniel van Vugt (vanvugt)]

Please elaborate about how step 3 failed. Please also try it again with a very simple password.

[Xavier Guillot (valeryan-24)]

Hi, I made some more testings.

First, I just updated my laptop to Ubuntu 17.10 : I confirm that writing "û" with circumflex accent still worked on artful and that password is accepted. It's like on my computer home : from Artful until 18.04 alpha, it worked in gdm with a "û" character. Since 10th March updates, no more.

On Ubuntu 17.10, on the contrary to bug 1716159, I still can type the Euro symbol € in the login field and it is well written... I will check later for current 18.04.

To resume :

gdm :

Debian Stretch 3.22.3 Type "u with circumflex accent" = û
Ubuntu 17.10 updated 03-27-2018 3.26.1 Type "u with circumflex accent" = û
Ubuntu 18.04 > 10th March 2018 3.27.92 Type "u with circumflex accent" = u

I made an upstream bug report to gdm in Gnome to see if there has been on their side a modification in code which made this circumflex accent no more writable and then password refused :
https://bugzilla.gnome.org/show_bug.cgi?id=794734

[Xavier Guillot (valeryan-24)]

Current 18.04, on gdm login field, if I type : € # $ @ ù é they are well and correctly written.

Only letters with an accent needing click on 2 keys are no more written correctly since 10th March updates on 18.04 (but work on 17.10) :

û and ü give u
ô and ö give o

French language and "French (alternative)" keyboard configuration
07:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Cape Verde XT [Radeon HD 7770/8760 / R7 250X] [1002:683d] (prog-if 00 [VGA controller])
Kernel driver in use: radeon
Kernel modules: radeon, amdgpu

[Sebastien Bacher (seb128)]

That looks like that gnome-shell regression, https://gitlab.gnome.org/GNOME/gnome-shell/issues/115 which has been fixed upstream and should be fixed when we update to 3.28.1

[baer (7-anton)]

This affects me as well. I am using:

- GNOME Shell 3.28.0
- GDM 3.28.1
- a 105-key ISO keyboard
- 'German' keyboard layout (_not_ the 'no dead keys' variant)

I am not using Ubuntu but I am adding this info here, since this issue seems to be much easier to find than the one on GNOME's GitLab.

When using the 'no dead keys' variant I can successfully enter single accent characters like '`' or '^' but not accented vowels like 'ò' (it becomes '`o'). When using the 'German' keyboard layout with dead keys, I cannot enter certain accented vowels either. Pressing [^] and [o] simply outputs 'o'. These keys have to be pressed _after_ each other usually. Numerous other special characters, that require simultaneous keypresses work though: €@§~#µ etc., e.g. [AltGr] + [a] --> æ. Compose keys do not work either and thus I believe that this is indeed issue #115 linked by seb1228 above.

Interestingly, the on-screen keyboard could not enter many of the simpler special characters, like 'ö' or 'ä' which are single keypresses on the keyboard, at all (see attached picture). In three instances I could enter 'š', 'å' and 'ß'. I deleted 'š' and could not reproduce any of those characters with the on-screen keyboard after that. This problem persists on the desktop though, so it appears to be unrelated?

I'll wait for GNOME Shell 3.28.1 and report back if that fixes my issue.

[baer (7-anton)]

Yep. GNOME Shell 3.28.1 fixed this issue for me.

[Bob Davidson (bobdavid)]

I am running the latest beta of 18.04 with upgrades. Since installation I try to log in the gdm screen and receive the message, "Sorry, that didn't work. Please try again." I get the same message when I try to log in to Update Manager. The app and gdm screen launch if I enter my password again.

[Daniel van Vugt (vanvugt)]

Bob, I think you want bug 1765261, not this one.