On 18.07.24 16:37, Thomas Köller wrote:
In a service file I am creating I use the BindReadOnlyPaths statement
like this:
root@htpc:~# cat /etc/systemd/system/vpn.service
[Unit]
Before = systemd-networkd.service
After = network-setup.service
Requisite = network-setup.service
ConditionPathExists = /run/systemd/network/50-tap_vpn.network
[Service]
Type = exec
TemporaryFileSystem = /etc
BindReadOnlyPaths = /etc/ssh
BindReadOnlyPaths = /etc/wpa_supplicant
BindReadOnlyPaths = /etc/dhcp
BindReadOnlyPaths = /etc/passwd
BindReadOnlyPaths = /etc/hosts
BindReadOnlyPaths = /etc/nsswitch.conf
NetworkNamespacePath = /run/netns/vpnlink
ExecStart = sh -c 'wpa_supplicant -B -i wlan_usb -c
/etc/wpa_supplicant/wpa_supplicant.conf; \
dhclient -4 wlan_usb; \
ssh -4 -i ~/.ssh/config-vpn -P vpn sarkovy'
[Install]
WantedBy = multi-user.target
The man page for systemd.exec states:
BindPaths=, BindReadOnlyPaths=
Configures unit-specific bind mounts. A bind mount makes a
particular file or directory available at an additional place in the
unit's view of the file system...
However, while the bind mounts for directories seem to work, those for
individual files do not. I get complaints about systemd being unable
to create the required mount points:
root@htpc:~# systemctl status vpn.service | cat
× vpn.service
Loaded: loaded (/etc/systemd/system/vpn.service; enabled; preset:
disabled)
Drop-In: /usr/lib/systemd/system/service.d
└─10-timeout-abort.conf
Active: failed (Result: exit-code) since Thu 2024-07-18 16:21:25
CEST; 27s ago
Process: 1597 ExecStart=sh -c wpa_supplicant -B -i wlan_usb -c
/etc/wpa_supplicant/wpa_supplicant.conf; dhclient -4
wlan_usb; ssh -4 -i ~/.ssh/config-vpn -P vpn sarkovy
(code=exited, status=226/NAMESPACE)
Main PID: 1597 (code=exited, status=226/NAMESPACE)
CPU: 10ms
Jul 18 16:21:25 htpc systemd[1]: Starting vpn.service...
Jul 18 16:21:25 htpc (sh)[1597]: Failed to create destination mount
point node '/run/systemd/mount-rootfs/etc/hosts', ignoring: Permission
denied
Jul 18 16:21:25 htpc (sh)[1597]: Failed to mount /etc/hosts to
/run/systemd/mount-rootfs/etc/hosts: No such file or directory
Jul 18 16:21:25 htpc (sh)[1597]: vpn.service: Failed to set up mount
namespacing: /etc/hosts: No such file or directory
Jul 18 16:21:25 htpc systemd[1]: vpn.service: Main process exited,
code=exited, status=226/NAMESPACE
Jul 18 16:21:25 htpc systemd[1]: vpn.service: Failed with result
'exit-code'.
Jul 18 16:21:25 htpc systemd[1]: Failed to start vpn.service.
Is there anyting I am doing wrong?
I now found that the problem only occurs with /etc/hosts, not with any
other file, Inside the processe's namspaces, there is no /etc/hosts at all:
root@htpc:~# pgrep ssh
2470
root@htpc:~# nsenter -at 2470 /bin/sh
sh-5.2# ls /etc
dhcp nsswitch.conf passwd resolv.conf ssh wpa_supplicant
sh-5.2#
