mirror of
https://github.com/systemd/systemd.git
synced 2026-11-06 05:17:24 +00:00
Adrian Reber
600fcc6dcb
Set DISSECT_IMAGE_TPM2_UNLOCK where unlocking an image's LUKS partitions via the local TPM2 is wanted and the caller is trusted: * systemd-dissect, an admin tool operating on an image the invoking user can read anyway; * systemd-nspawn --image=, which already prompts for a passphrase interactivly, so TPM2 first and passphrase second is the natural order; * systemd-sysext/systemd-confext, which decrypt without any passphrase, so extension images sealed to the host can be activated without user interaction. For sysext/confext setting the flag at merge time is not enough: before merging, the extension-release metadata is read via image_read_metadata() in discover-image.c, which uses its own flag set and would already fail with -ENOKEY on an encrypted image. Give it an extra_flags parameter and pass the flag from there, too; the other callers (machined, portabled) pass 0 and keep their behaviour. Two units need adjusting for this to work when started by the service manager: systemd-nspawn@.service has DevicePolicy=closed, so allow /dev/tpmrm0 there, and the sysext/confext services are not ordered against the TPM2 device showing up, so order them after tpm2.target like the pcr* services. The initrd variants cannot be ordered the same way: they run before local-fs-pre.target, while the software TPM fallback only becomes available after the early ESP mount, which is ordered after local-fs-pre.target, so a static After=tpm2.target would be an ordering cycle with systemd.tpm2_software_fallback=1. Hence systemd-tpm2-generator adds the ordering as a drop-in instead, unless the fallback is in use. That drop-in also orders them after systemd-pcrphase-initrd.service: nothing else guarantees the "enter-initrd" phase has been measured into PCR 11 before the initrd extension units merge their images (the barrier's Before=systemd-sysext.service is a leftover from when that unit was also used in the initrd), so tokens bound to a signed PCR 11 policy or a pcrlock policy would race the measurement. Deliberately not enabled for now: RootImage=/ExtensionImages=/MountImages= in units, portabled and gpt-auto. For those an unconditional default is probably not wanted but a per-unit or per-image switch, which is left for a follow-up. systemd-mountfsd, which unprivileged systemd-dissect and systemd-nspawn delegate to, keeps its own flag set and does not honour the flag, hence TPM2 unlocking is only available when running privileged; the man pages say so. Document the behaviour and $SYSTEMD_DISSECT_TPM2_UNLOCK= in the dissect, nspawn and sysext man pages and in docs/ENVIRONMENT.md.
60 lines
2.1 KiB
Plaintext
60 lines
2.1 KiB
Plaintext
# SPDX-License-Identifier: LGPL-2.1-or-later
|
|
#
|
|
# This file is part of systemd.
|
|
#
|
|
# systemd is free software; you can redistribute it and/or modify it
|
|
# under the terms of the GNU Lesser General Public License as published by
|
|
# the Free Software Foundation; either version 2.1 of the License, or
|
|
# (at your option) any later version.
|
|
|
|
[Unit]
|
|
Description=Container %i
|
|
Documentation=man:systemd-nspawn(1)
|
|
Wants=modprobe@tun.service modprobe@loop.service modprobe@dm_mod.service
|
|
PartOf=machines.target
|
|
Before=machines.target
|
|
After=network.target modprobe@tun.service modprobe@loop.service modprobe@dm_mod.service
|
|
RequiresMountsFor=/var/lib/machines/%i
|
|
|
|
[Service]
|
|
# Make sure the DeviceAllow= lines below can properly resolve the 'block-loop' expression (and others)
|
|
ExecStart=systemd-nspawn --quiet --keep-unit --boot --link-journal=try-guest --network-veth -U --settings=override --machine=%i
|
|
ExecStopPost=systemd-nspawn --cleanup --machine=%i
|
|
KillMode=mixed
|
|
Type=notify
|
|
RestartForceExitStatus=133
|
|
SuccessExitStatus=133
|
|
Slice=machine.slice
|
|
Delegate=yes
|
|
DelegateSubgroup=supervisor
|
|
CoredumpReceive=yes
|
|
TasksMax=16384
|
|
TimeoutSec=2min
|
|
{{SERVICE_WATCHDOG}}
|
|
|
|
{# Enforce a strict device policy, similar to the one nspawn configures (in
|
|
# nspawn-register.c:append_machine_properties()) when it allocates its own
|
|
# scope unit. Make sure to keep these policies in sync if you change them! #}
|
|
DevicePolicy=closed
|
|
DeviceAllow=/dev/net/tun rwm
|
|
DeviceAllow=char-pts rw
|
|
DeviceAllow=/dev/fuse rwm
|
|
|
|
# nspawn itself needs access to /dev/loop-control and /dev/loop, to implement
|
|
# the --image= option. Add these here, too.
|
|
DeviceAllow=/dev/loop-control rw
|
|
DeviceAllow=block-loop rw
|
|
DeviceAllow=block-blkext rw
|
|
|
|
# nspawn can set up LUKS encrypted loopback files, in which case it needs
|
|
# access to /dev/mapper/control and the block devices /dev/mapper/*.
|
|
DeviceAllow=/dev/mapper/control rw
|
|
DeviceAllow=block-device-mapper rw
|
|
|
|
# nspawn unlocks LUKS encrypted images via a TPM2 token enrolled in them, in
|
|
# which case it needs access to the TPM2 resource manager device.
|
|
DeviceAllow=/dev/tpmrm0 rw
|
|
|
|
[Install]
|
|
WantedBy=machines.target
|