$XDG_RUNTIME_DIR is created with invalid permissions (755, should be 700)

[velle]

Windows Version

Microsoft Windows [Version 10.0.19045.3693]

WSL Version

2.0.9.0

Are you using WSL 1 or WSL 2?

• WSL 2
• WSL 1

Kernel Version

5.15.133.1-1

Distro Version

Ubuntu 22.04

Other Software

No response

Repro Steps

I created a container from the default WSL image of Ubuntu 22.04, and logged in.

Check the file permissions for $XDG_RUNTIME_DIR:

$ stat -c '%A %a %n' $XDG_RUNTIME_DIR
drwxr-xr-x 755 /run/user/1000/

Use Qt's QStandardPaths

Run a piece of software or a script that depends on Qt's QStandardPath, e.g. this minimal Python script:

#!/usr/bin/env python3
from PyQt6.QtCore import QStandardPaths
QStandardPaths.standardLocations(QStandardPaths.StandardLocation.RuntimeLocation)

Expected Behavior

Expected file permissions:

According to the XDG Base Directory Specification it should always have permissions 700, ie:

$XDG_RUNTIME_DIR defines the base directory relative to which user-specific non-essential runtime files and other file objects (such as sockets, named pipes, ...) should be stored. The directory MUST be owned by the user, and he MUST be the only one having read and write access to it. Its Unix access mode MUST be 0700.

Expected output:

$ stat -c '%A %a %n' $XDG_RUNTIME_DIR
drwxr-xr-x 700 /run/user/1000/

Expected Qt behavior

No warnings or errors.

Actual Behavior

Actual file permissions:

$ stat -c '%A %a %n' $XDG_RUNTIME_DIR
drwxr-xr-x 755 /run/user/1000/

Actual Qt behavior

QStandardPaths: wrong permissions on runtime directory /run/user/1000/, 0755 instead of 0700

Diagnostic Logs

No response

[OneBlue]

@velle: Do you have systemd enabled ? If so systemd actually creates this folder. You can validate that by running:

journalctl | grep -iF /run/user

[velle]

Yes, I have systemd enabled. Here is the output:

$ journalctl -b | grep -iF /run/user
Dec 14 15:20:48 ELCON45223 systemd[1]: Starting User Runtime Directory /run/user/1000...
Dec 14 15:20:48 ELCON45223 systemd[1]: Finished User Runtime Directory /run/user/1000.

Before posting this issue, I wrote the systemd-devel mailing list: https://lists.freedesktop.org/archives/systemd-devel/2023-November/049679.html. If I understand correctly, they believe that something in WSL creates those folders before systemd tries to, and therefore systemd does not touch those folders.

From https://lists.freedesktop.org/archives/systemd-devel/2023-November/049691.html:

So logind invokes [email protected], but it sees the
existing directory and does nothing. I would suggest asking this
question on WSL support channels.

[ashemedai]

With 2.0.14.0 and Debian 12 with systemd enabled I cannot reproduce this:

[drphrozen]

I have the same issue (trying to run imhex):

$ imhex
terminate called after throwing an instance of 'xdg::BaseDirectoryException'
  what():  $XDG_RUNTIME_DIR must have 0700 as permissions
[1]    12114 IOT instruction  imhex

$ stat -c '%A %a %n' $XDG_RUNTIME_DIR
drwxr-xr-x 755 /run/user/1000/

PS C:\> wsl --version
WSL-version: 2.0.9.0
Kerneversion: 5.15.133.1-1
WSLg-version: 1.0.59
MSRDC-version: 1.2.4677
Direct3D-version: 1.611.1-81528511
DXCore-version: 10.0.25131.1002-220531-1700.rs-onecore-base2-hyp
Windows-version: 10.0.22631.3007

[shoffmeister]

The impact of this cannot be under-estimated:

With systemd enabled, none of the tools mentioned above will start. I.e. anything using the Qt UI toolkit will simply fail to start.

Symptoms are a Real Crash (imhex, see above, reproduced), or anything from the KDE ecosystem, such as konsole, filelight, kate, all of which start with a black/blank/transparent screen.

And it's always

❯ filelight
QStandardPaths: wrong permissions on runtime directory /run/user/1000/, 0755 instead of 0700
QStandardPaths: wrong permissions on runtime directory /run/user/1000/, 0755 instead of 0700
QStandardPaths: wrong permissions on runtime directory /run/user/1000/, 0755 instead of 0700

[ASadMuon-6671011]

@shoffmeister yes exactly, the impact is way more than it seems, did you figure out a way to fix this? i've been breaking my head over it the past whole day

[shoffmeister]

I have not looked into this in detail, but simply redefining XDG_RUNTIME_DIR to some other location, with the correct privileges, should suffice.

Following https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html, something as simple as

export XDG_RUNTIME_DIR=/tmp/my-xdg-runtime-dir
mkdir -p $XDG_RUNTIME_DIR
chmod 700 $XDG_RUNTIME_DIR

filelight&

could work.

[BrentHuang]

me too.
QStandardPaths: wrong permissions on runtime directory /var/run/user/1000, 0755 instead of 0700