[Bug]: VBoxCreateUSBNode.sh missing from initramfs causes udev failures on Fedora 43 / VirtualBox 7.2.8 / systemd 258

[pgnd]

Version

7.2.8

Host OS Type

macOS

Host OS name + version

Fedora 43

Host Architecture

x86

Guest OS Type

all

Guest Architecture

x86

Guest OS name + version

Fedora 43

Component

Unspecified

What happened?

VBoxCreateUSBNode.sh missing from initramfs causes udev failures on Fedora 43 / VirtualBox 7.2.8 / systemd 258

Component: Packaging / udev rules / initramfs (Linux host)

Severity: Medium -- dmesg noise on every boot; USB passthrough device nodes not created during early boot

Observable Behavior

On every boot, dmesg contains repeated errors of the form:

(udev-worker)[NNN]: <device>: Failed to find and pin callout binary "/usr/lib/virtualbox/VBoxCreateUSBNode.sh": No such file or directory
(udev-worker)[NNN]: <device>: Failed to execute '/usr/lib/virtualbox/VBoxCreateUSBNode.sh 189 NNN NN', ignoring: No such file or directory

The errors appear at ~3-4 seconds into boot, for every USB device enumerated. The script exists on the real root filesystem (/usr/lib/virtualbox/VBoxCreateUSBNode.sh, mode 755, root:root, installed by the VirtualBox RPM). The errors are not caused by a missing file on the real root.

Analysis

Two issues appear to combine to produce the failure.

Issue 1: Rule Path

The udev rule is generated by /usr/lib/virtualbox/vboxdrv.sh setup during package installation and written to /etc/udev/rules.d/60-vboxdrv.rules. The generator function udev_write_usb() (lines 225-228 of vboxdrv.sh in 7.2.8) emits the rule referencing $INSTALLATION_DIR/VBoxCreateUSBNode.sh, which resolves to /usr/lib/virtualbox/VBoxCreateUSBNode.sh.

The RPM does not install a udev rules file -- the rule is generated at install/setup time only. vboxdrv.service's start action loads kernel modules but does not regenerate the rule.

Issue 2: Initramfs

The errors appear to occur during the initramfs boot phase, before switch_root to the real filesystem. dracut includes /etc/udev/rules.d/60-vboxdrv.rules in the initramfs (as it does all udev rules), but does not include /usr/lib/virtualbox/VBoxCreateUSBNode.sh. The script is therefore absent from the initramfs.

systemd-udev's pin_callout_binary() (src/basic/build-path.c) calls open(path, O_PATH|O_CLOEXEC) on the callout binary before executing it. If the script does not exist in the initramfs filesystem, this call would fail with ENOENT -- which matches the observed error.

Source code inspection of systemd 258 (src/basic/build-path.c, src/basic/path-util.c, src/udev/udev-spawn.c) shows pin_callout_binary() has no path allowlist or namespace restriction -- it is a plain open() call. This is consistent with the failure being a missing file rather than a permission or policy issue.

Additional Complication: vboxusers Group

Even after making the script available in the initramfs, it fails with exit code 1 because VBoxCreateUSBNode.sh calls chown root:vboxusers, and the vboxusers group does not appear to exist in the initramfs's minimal /etc/group.

Affected Versions

• VirtualBox 7.2.x -- Oracle upstream Fedora packaging, confirmed: VirtualBox-7.2-7.2.8_173730_fedora40-1.x86_64 (Vendor: Oracle Corporation)
• Host OS: Fedora Linux 43 (Forty Three), kernel 6.19.11-200.fc43.x86_64, systemd-udev 258.7-1.fc43.x86_64
• Likely affects any Linux distribution using dracut for initramfs generation with VirtualBox installed, though this has not been tested on other distributions

Proposed Fix

If the above analysis is correct, the following packaging changes would address the issue:

1. Rule path -- update vboxdrv.sh to emit /usr/lib/udev/VBoxCreateUSBNode.sh instead of $INSTALLATION_DIR/VBoxCreateUSBNode.sh in udev_write_usb() (lines 225-228 in 7.2.8). /usr/lib/udev/ is the standard location for udev callout helpers.

2. Script location -- install VBoxCreateUSBNode.sh to /usr/lib/udev/VBoxCreateUSBNode.sh as a real file, not a symlink. A symlink appears insufficient: open() follows it and the target /usr/lib/virtualbox/VBoxCreateUSBNode.sh would still not be in the initramfs. The existing /usr/lib/virtualbox/VBoxCreateUSBNode.sh can remain for compatibility.

3. Initramfs -- packaging would need to ensure:

   • /usr/lib/udev/VBoxCreateUSBNode.sh is included in the initramfs
   • The vboxusers group is present in the initramfs /etc/group

User-Applied Workaround (Verified on Fedora 43)

The following workaround resolved the issue on the reporter's system. It is not guaranteed to work in all configurations.

(1) copy the script to the udev callout path (not symlink):

cp /usr/lib/virtualbox/VBoxCreateUSBNode.sh /usr/lib/udev/VBoxCreateUSBNode.sh
chmod 755 /usr/lib/udev/VBoxCreateUSBNode.sh

(2) patch vboxdrv.sh to emit the correct path in generated rules:

sed -i 's|$INSTALLATION_DIR/VBoxCreateUSBNode.sh|/usr/lib/udev/VBoxCreateUSBNode.sh|g' /usr/lib/virtualbox/vboxdrv.sh

(3) regenerate the rule file:

/usr/lib/virtualbox/vboxdrv.sh setup

(4) tell dracut to include the script in the initramfs, and attempt to add the vboxusers group (note: it is unclear whether the groups+= line is honoured by dracut or whether the module in step 5 is solely responsible for the group -- both were present when the fix was verified):

cat > /etc/dracut.conf.d/vbox-udev.conf << 'EOF'
install_items+=" /usr/lib/udev/VBoxCreateUSBNode.sh "
groups+=" vboxusers "
EOF

(5) create a dracut module to add the vboxusers group to the initramfs:

mkdir -p /usr/lib/dracut/modules.d/99vboxusb
cat > /usr/lib/dracut/modules.d/99vboxusb/module-setup.sh << 'EOF'
#!/bin/bash
check() { return 0; }
depends() { return 0; }
install() {
    local gid
    gid=$(getent group vboxusers 2>/dev/null | cut -d: -f3)
    [[ -n "$gid" ]] && echo "vboxusers:x:${gid}:" >> "${initdir}/etc/group"
}
EOF
chmod +x /usr/lib/dracut/modules.d/99vboxusb/module-setup.sh

(6) rebuild the initramfs and reboot:

dracut -f
reboot

After reboot, dmesg | grep VBox showed only:

VBoxNetFlt: Successfully started.
VBoxNetAdp: Successfully started.

Workaround Caveats

• Steps 2 and 3 are overwritten on VirtualBox package update (which re-runs vboxdrv.sh setup) and must be re-applied.
• Steps 4 and 5 persist across VirtualBox updates.
• Step 1 (the copied script) becomes stale if VBoxCreateUSBNode.sh is updated by a package update and must also be refreshed.

References

• systemd pin_callout_binary source: https://github.com/systemd/systemd/blob/main/src/udev/udev-spawn.c

How can we reproduce this?

see above

Did you upload all of your necessary log files, screenshots, etc.?

• Yes, I've uploaded all pertinent files to this issue.