[Bug 1811580] Re: systemd fails to start sshd at reboot

[Dimitri John Ledkov]

@ David (dasoto)

nvidia at tegra-ubuntu:/$ ls -la
total 108
drwxrwxr-x 23 ubuntu ubuntu 4096 Oct 30 17:36 .
drwxrwxr-x 23 ubuntu ubuntu 4096 Oct 30 17:36 ..
drwxrwxr-x 22 ubuntu ubuntu 4096 Oct 29 20:31 lib
drwxr-xr-x 5 nvidia nvidia 4096 Oct 29 20:36 media
-rw-r--r-- 1 ubuntu ubuntu 62 May 17 2018 README.txt

The above look very bad too me.

Imho /README.txt shouldn't be there at all.
Not sure why /media is owned by nvidia:nvidia, usually /media is owned by root.
Ditto / and /lib should be owned by root. It is a security vulnerability for unpriviledged user to own these top level directories.

Can you please try this:
$ sudo chown root:root / /lib /media

And check if systemd-tmpfiles works after that?

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https://bugs.launchpad.net/bugs/1811580

Title:
  systemd fails to start sshd at reboot

Status in systemd package in Ubuntu:
  Confirmed

Bug description:
  Ubuntu 16.04.5, systemd 229-4ubuntu21.15

  The latest systemd update has somehow changed the method it uses to
  start 'ssh.service' i.e. 'sshd'. systemd fails to start sshd if
  /etc/ssh/sshd_config contains "UsePrivilegeSeparation yes" and
  /var/run/sshd/ does not already exist. Being as this is the default,
  virtually EVERY Ubuntu 16.04 server in the world has
  UsePrivilegeSeparation set to yes. Furthermore, at the time when the
  user performs 'apt upgrade' and receives the newest version of
  systemd, /var/run/sshd/ already exists, so sshd successfully reloads
  for as long as the server doesn't get rebooted. BUT, as soon as the
  server is rebooted for any reason, /var/run/sshd/ gets cleaned away,
  and sshd fails to start, causing the remote user to be completely
  locked out of his system. This is a MAJOR issue for millions of VPS
  servers worldwide, as they are all about to get locked out of their
  servers and potentially lose data. The next reboot is a ticking time
  bomb waiting to spring. The bomb can be defused by implicitly setting
  'UsePrivilegeSeparation no' in /etc/ssh/sshd_config, however
  unsuspecting administrators are bound to be caught out by the
  millions. I got caught by it in the middle of setting up a new server
  yesterday, and it took a whole day to find the source.

  The appropriate fix would be to ensure that systemd can successfully
  'start ssh.service' even when 'UsePrivilegeSeparation yes' is set.
  systemd needs to test that /var/run/sshd/ exists before starting sshd,
  just as the init.d script for sshd does. openssl could also be patched
  so that UsePrivilegeSeparation is no longer enabled by default,
  however that is not going to solve the problem for millions of pre-
  existing config files. Only an update to openssl to force-override
  that flag to 'no' would solve the problem. Thus systemd still needs to
  be responsible for ensuring that it inits sshd properly by ensuring
  that /var/run/sshd/ exists before it sends the 'start' command.

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