[systemd-devel] WSL Ubuntu creates XDG_RUNTIME_DIR with incorrect permissions

Wed Nov 29 18:59:00 UTC 2023

Thanks both of you! :)

I have taken some time to digest your answers. And in particular I have
tried to investigate this line closer:

*Nov 27 12:34:22 tumbleweed unknown: WSL (2): Creating login session for
andrei*

I have found the equivalent log line on my WSL Ubuntu. I was hoping I could
find out more about where its coming from; ie which process / service
prints this. But journalctl does not tell me much about the origin.

*journalctl -b --grep "Creating login session for velle" -o verboseWed
2023-11-29 18:41:19.982271 CET
[s=d318bdab5d1f4ad7a48a947e6fff4a01;i=2d53;b=c8682ff139cf40da8326fd63d7c34d7c;m=1649>
  _TRANSPORT=kernel    _MACHINE_ID=967980c77d4743298ceaeb5d512bf388
_HOSTNAME=ELCON45223    PRIORITY=6    SYSLOG_FACILITY=1    MESSAGE=WSL (2):
Creating login session for velle
_BOOT_ID=c8682ff139cf40da8326fd63d7c34d7c
_SOURCE_MONOTONIC_TIMESTAMP=23368229*

Most log entries in journalctl has a _PID field, but some don't, and this
one does not. Why? What does it tell, that a log entry has no _PID? As far
as I know ever process has an PID, even systemd itself has a PID (which is
always 1). Or am I wrong about that? I see now reason why those PIDs are
not saved together with the log entries.

On Mon, Nov 27, 2023 at 10:37 AM Andrei Borzenkov <arvidjaar at gmail.com>
wrote:

> On Mon, Nov 27, 2023 at 1:06 AM Thomas Larsen Wessel <mrvelle at gmail.com>
> wrote:
> >>
> >> WSL does not use systemd by default.
> >
> >
> > According to this article, it systemd has been default on WSL Ubuntu
> since june 2023. https://learn.microsoft.com/en-us/windows/wsl/systemd
> >
> > "Systemd is now the default for the current version of Ubuntu that will
> be installed using the wsl --install command default."
> >
> > Also when I look in the /var/log/auth.log, there are many lines with
> systemd, e.g.:
> >
> > Nov 25 22:30:14 ELCON45223 systemd-logind[155]: New session 6 of user
> velle.
> > Nov 25 22:30:14 ELCON45223 systemd: pam_unix(systemd-user:session):
> session opened for user velle(uid=1000) by (uid=0)
> >
> > Could someone please help me understand exactly which part creates this
> XDG_RUNTIME_DIR folder?
>
> /run/user/$UID for the "console" session (the one you get when
> starting a WSL instance) is created by WSL before systemd. Adding "ls
> -l /run/user" to user-runtime-dir at 1000.service ExecStartPre:
>
> Nov 27 12:34:22 tumbleweed unknown: WSL (2) ERROR:
> WaitForBootProcess:3237: /sbin/init failed to start within 10000
> Nov 27 12:34:22 tumbleweed unknown: ms
> Nov 27 12:34:22 tumbleweed unknown: WSL (2): Creating login session for
> andrei
> ...
> Nov 27 12:34:22 tumbleweed systemd[1]: Created slice User Slice of UID
> 1000.
> Nov 27 12:34:22 tumbleweed systemd[1]: Starting User Runtime Directory
> /run/user/1000...
> Nov 27 12:34:22 tumbleweed ls[520]: total 0
> Nov 27 12:34:22 tumbleweed ls[520]: drwxr-xr-x 4 andrei users 120 Nov
> 27 12:34 1000
> Nov 27 12:34:22 tumbleweed systemd-logind[160]: New session 11 of user
> andrei.
> Nov 27 12:34:22 tumbleweed systemd[1]: Finished User Runtime Directory
> /run/user/1000.
>
> So logind invokes user-runtime-dir at 1000.service, but it sees the
> existing directory and does nothing. I would suggest asking this
> question on WSL support channels.
>
> > Is it part of the systemd repo or not? And if the answer is (or may be)
> different between Ubuntu and WSL Ubuntu, I would be happy if you share what
> you know about any any of those cases :) Right now, I barely know where to
> report this issue.
> >
> >
> > On Sun, Nov 26, 2023 at 10:07 AM Andrei Borzenkov <arvidjaar at gmail.com>
> wrote:
> >>
> >> On 26.11.2023 02:39, Thomas Larsen Wessel wrote:
> >> > I set up WSL on Windows 10 and created an instance from the default
> Ubuntu
> >> > 22.04 image.
> >> >
> >> > I ran some (non-GUI) software that somehow relies on Qt, and
> apparently Qt
> >> > does some checks on the XDG environment, so I got the following.
> >> >
> >> > *Warning: QStandardPaths: wrong permissions on runtime directory
> >> > /run/user/1000/, 0755 instead of 0700*
> >> >
> >> > And yes, all the user folders are set to 755, including much of their
> >> > content, which violates the XDG Base Directory Specification.
> (screenshot:
> >> > https://i.imgur.com/ISn3ebh.png).
> >> >
> >> > As far as I can understand, its some part of systemd, that creates
> this
> >> > folder. So is this an issue with systemd?
> >> >
> >>
> >> WSL does not use systemd by default.
> >>
> >> > The validate_runtime_directory in pam_systemd already does a number of
> >> > checks on XDG_RUNTIME_DIR. How about also checking if the permissions
> are
> >> > correct/valid?
> >> >
> >> > Sincerely, Thomas
> >> >
> >>
>
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