Bug#979562: lightdm session termination does not stop xscreensaver

[Michael Biebl]

Control: reassign -1 xscreensaver

I don't see a systemd problem here, so re-assigning to xscreensaver.

Am 08.01.21 um 13:04 schrieb Eduard Bloch:
> Package: systemd
> Version: 247.2-4
> Severity: serious
> 
> Hi,
> 
> I am reporting this with high severity because it might affect system
> security.
> 
> For details of this issue, see 978589. There are different symptoms to
> see but the originating cause is apparently the same:
> 
>   - xscreensaver user service is enabled as documented in its README
>   - lightdm starts the service in its internal user session (owned by
>     "lightdm" user)
>   - lightdm stops its session when the login happens. However,
>     xscreensaver process is NOT terminated for unknown reason.
>   - having this xscreensaver hanging around disturbs the startup of
>     another xscreensaver process in the new user session
>   - after ~15s the old xscreensaver process (from lightdm) is finally
>     dead, apparently a SIGTERM is emited only then!
> 
> Visible symptoms:
> 
> In the meantime, someone might lock the system (by xscreensaver-command)
> and go away, assuming that xscreensaver is locked. And then it suddenly
> dies.
> 
> Same things happens if xscreensaver is invoked from .xsession or similar
> contents instead of user service.
> 
> Best regards,
> Eduard.
> 
> -- Package-specific info:
> 
> -- System Information:
> Debian Release: bullseye/sid
>    APT prefers unstable-debug
>    APT policy: (500, 'unstable-debug'), (500, 'unstable'), (500, 'stable'), (1, 'experimental-debug'), (1, 'experimental')
> Architecture: amd64 (x86_64)
> Foreign Architectures: i386
> 
> Kernel: Linux 5.10.5+ (SMP w/12 CPU threads)
> Kernel taint flags: TAINT_OOT_MODULE
> Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8), LANGUAGE not set
> Shell: /bin/sh linked to /bin/bash
> Init: systemd (via /run/systemd/system)
> LSM: AppArmor: enabled
> 
> Versions of packages systemd depends on:
> ii  adduser                          3.118
> ii  libacl1                          2.2.53-9
> ii  libapparmor1                     2.13.6-3
> ii  libaudit1                        1:3.0-2
> ii  libblkid1                        2.36.1-4
> ii  libc6                            2.31-9
> ii  libcap2                          1:2.44-1
> ii  libcrypt1                        1:4.4.17-1
> ii  libcryptsetup12                  2:2.3.4-1
> ii  libgcrypt20                      1.8.7-2
> ii  libgnutls30                      3.7.0-5
> ii  libgpg-error0                    1.38-2
> ii  libip4tc2                        1.8.6-1
> ii  libkmod2                         28-1
> ii  liblz4-1                         1.9.3-1
> ii  liblzma5                         5.2.5-1.0
> ii  libmount1                        2.36.1-4
> ii  libpam0g                         1.4.0-2
> ii  libseccomp2                      2.5.1-1
> ii  libselinux1                      3.1-2+b2
> ii  libsystemd0                      247.2-4
> ii  libzstd1                         1.4.8+dfsg-1
> ii  mount                            2.36.1-4
> ii  systemd-timesyncd [time-daemon]  247.2-4
> ii  util-linux                       2.36.1-4
> 
> Versions of packages systemd recommends:
> ii  dbus  1.12.20-1
> 
> Versions of packages systemd suggests:
> ii  policykit-1        0.105-29
> pn  systemd-container  <none>
> 
> Versions of packages systemd is related to:
> pn  dracut           <none>
> ih  initramfs-tools  0.139
> ii  libnss-systemd   247.2-4
> ii  libpam-systemd   247.2-4
> ii  udev             247.2-4
> 
> -- no debconf information
> 
> --
> Chirurgen sind die einzigen Menschen, die ohne fremden Blinddarm und
> ohne fremde Mandeln nicht leben können.
> 		-- Peter Sellers
> 


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