Erro em vez de solicitação de senha quando privilégios de administrador são necessários

Question

Recentemente, notei alguns problemas no meu sistema:
1. erro "Não é possível instalar ...: você não tem permissão para instalar software" quando tento instalar qualquer coisa de "software Ubuntu"
2. Nada acontece, quando eu pressiono "Desbloquear" nas configurações do usuário. Tenho certeza de que ambos os problemas estão conectados. Nenhuma delas é muito significativa para mim (o apt e o useradd funcionam corretamente).

Instalar software através do gui funcionou antes, então tenho certeza, é uma atualização ou algum pacote, que instalei, que causa o problema.

EDIT:
Eu encontrei esta saída no journalctl em situações descritas acima:

maj 24 23:33:21 tfrankowski-UX32LN kernel: polkitd[6183]: segfault at 8 ip 00007f91635cbfa6 sp 00007ffdccb6c790 error 4 in libpolkit-backend-1.so.0.0.0[7f91635bc000+18000]
maj 24 23:33:21 tfrankowski-UX32LN systemd[1]: polkit.service: Main process exited, code=dumped, status=11/SEGV
maj 24 23:33:21 tfrankowski-UX32LN systemd[1]: polkit.service: Failed with result 'core-dump'.
maj 24 23:33:21 tfrankowski-UX32LN org.gnome.Shell.desktop[1163]: PolicyKit daemon disconnected from the bus.
maj 24 23:33:21 tfrankowski-UX32LN org.gnome.Shell.desktop[1163]: We are no longer a registered authentication agent.
maj 24 23:33:21 tfrankowski-UX32LN dbus-daemon[1044]: [system] Activating via systemd: service name='org.freedesktop.PolicyKit1' unit='polkit.service' requested by ':1.12' (uid=0 pid=1048 comm="/usr/sbin/NetworkManager --no-daemon " label="unconfined")
maj 24 23:33:21 tfrankowski-UX32LN gnome-control-c[2116]: Error acquiring permission: GDBus.Error:org.freedesktop.DBus.Error.NoReply: Message recipient disconnected from message bus without replying
maj 24 23:33:21 tfrankowski-UX32LN org.gnome.Shell.desktop[1740]: PolicyKit daemon disconnected from the bus.
maj 24 23:33:21 tfrankowski-UX32LN org.gnome.Shell.desktop[1740]: We are no longer a registered authentication agent.
maj 24 23:33:21 tfrankowski-UX32LN systemd[1]: Starting Authorization Manager...
maj 24 23:33:21 tfrankowski-UX32LN polkitd[6411]: started daemon version 0.105 using authority implementation 'local' version '0.105'
maj 24 23:33:21 tfrankowski-UX32LN dbus-daemon[1044]: [system] Successfully activated service 'org.freedesktop.PolicyKit1'
maj 24 23:33:21 tfrankowski-UX32LN systemd[1]: Started Authorization Manager.
maj 24 23:33:21 tfrankowski-UX32LN org.gnome.Shell.desktop[1163]: PolicyKit daemon reconnected to bus.
maj 24 23:33:21 tfrankowski-UX32LN org.gnome.Shell.desktop[1163]: Attempting to re-register as an authentication agent.
maj 24 23:33:21 tfrankowski-UX32LN org.gnome.Shell.desktop[1740]: PolicyKit daemon reconnected to bus.
maj 24 23:33:21 tfrankowski-UX32LN org.gnome.Shell.desktop[1740]: Attempting to re-register as an authentication agent.
maj 24 23:33:21 tfrankowski-UX32LN polkitd(authority=local)[6411]: Registered Authentication Agent for unix-session:c1 (system bus name :1.28 [/usr/bin/gnome-shell], object path /org/freedesktop/PolicyKit1/AuthenticationAgent, locale en_US.UTF-8)
maj 24 23:33:21 tfrankowski-UX32LN org.gnome.Shell.desktop[1163]: We are now a registered authentication agent.
maj 24 23:33:21 tfrankowski-UX32LN polkitd(authority=local)[6411]: Registered Authentication Agent for unix-session:2 (system bus name :1.76 [/usr/bin/gnome-shell], object path /org/freedesktop/PolicyKit1/AuthenticationAgent, locale en_US.UTF-8)
maj 24 23:33:21 tfrankowski-UX32LN org.gnome.Shell.desktop[1740]: We are now a registered authentication agent.

    

Answer 1

O problema parece estar relacionado com este arquivo

/etc/polkit-1/localauthority.conf.d/02-allow-colord.conf

Ele se origina de uma instalação manual do xRDP (consulte a seção de comentários) ou do x2go ou de outros aplicativos de área de trabalho remota.

A solução vem do mesmo site:

Exclua 02-allow-colord.conf

sudo rm /etc/polkit-1/localauthority.conf.d/02-allow-colord.conf 

Crie 45-allow-colord.pkla:

sudo vi /etc/polkit-1/localauthority/50-local.d/45-allow-colord.pkla

com conteúdo:

[Allow Colord all Users]
Identity=unix-user:*
Action=org.freedesktop.color-manager.create-device;org.freedesktop.color-manager.create-profile;org.freedesktop.color-manager.delete-device;org.freedesktop.color-manager.delete-profile;org.freedesktop.color-manager.modify-device;org.freedesktop.color-manager.modify-profile
ResultAny=no
ResultInactive=no
ResultActive=yes

então

sudo systemctl restart polkit.service