Bug#949698: elogind: deletes users’ files under /dev/shm/ on logout

[Dolphin Oracle]

should you not be using /tmp for that rather that /dev/shm?

I think /tmp should be set up as a tmpfs and will then not persist across
reboots.  /var/tmp is for tmp space that needs to persist across reboots.



On Thu, Jan 23, 2020 at 2:36 PM Thorsten Glaser <tg at mirbsd.de> wrote:

> Package: elogind
> Version: 241.3-1+debian2
> Severity: critical
> Justification: breaks unrelated software
>
> I’m using a scheme in which I store ssh-agent and gpg-agent information
> across all logins (local X session or ssh or xrdp) under /dev/shm/ since
> I needed space that an unprivileged user can use and that doesn’t persist
> across reboots.
>
> Since installing elogind, logging out from SSH sessions then on again
> both breaks gpg-agent as well as makes ssh-agent instances multiply and,
> thus, lose their loaded keys to the user.
>
> Tons of searching and debugging eventuall led me, with strace as root on
> it, to the culprit: elogind
>
> lrwxrwxrwx 1 root root 0 Jan 23 20:21 /proc/3061/exe ->
> /lib/elogind/elogind*
>
> 3061  unlinkat(22, "info2", 0)          = 0
> 3061  unlinkat(21, ".ssh-2339", AT_REMOVEDIR) = 0
>
>
> Cease that instantly. This breaks unrelated software on the system,
> considering that the user’s processes are still running, even if they
> logged out from all ssh sessions. In particular, this will also break
> software that runs as the user, dæmonised, that uses shared memory.
>
> If you have to clean up after yourselves, keep a list and track of the
> files you created and will later need to delete.
>
> It might be a good idea to see whether systemd does the same and, if
> so, clone this bugreport and assign the clone to them. I’m not running
> systemd, so I can’t do that myself easily.
>
> -- System Information:
> Debian Release: bullseye/sid
>   APT prefers unreleased
>   APT policy: (500, 'unreleased'), (500, 'buildd-unstable'), (500,
> 'unstable'), (100, 'experimental')
> Architecture: x32 (x86_64)
> Foreign Architectures: i386, amd64
>
> Kernel: Linux 5.4.0-2-amd64 (SMP w/4 CPU cores)
> Kernel taint flags: TAINT_FIRMWARE_WORKAROUND
> Locale: LANG=C, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=C
> (charmap=UTF-8)
> Shell: /bin/sh linked to /bin/lksh
> Init: sysvinit (via /sbin/init)
>
> Versions of packages elogind depends on:
> ii  dbus         1.12.16-2
> ii  debconf      1.5.73
> ii  libacl1      2.2.53-5
> ii  libc6        2.29-9
> ii  libcap2      1:2.27-1
> ii  libelogind0  241.3-1+debian2
> ii  libselinux1  3.0-1
> ii  libudev1     244-3
> ii  lsb-base     11.1.0
>
> Versions of packages elogind recommends:
> ii  libpam-elogind  241.3-1+debian2
> ii  policykit-1     0.105-26
>
> elogind suggests no packages.
>
> -- no debconf information
>
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