When machined is started earlier than DBus service, the execution is
blocked by reading properties through DBus for a while. Let's return
earlier if the DBus connection is not ready.
Fixes issue reported in #40414.
This is a follow-up for 119d332d9c and
ensures the check only is applied to the system instance of machined. It
doesn't really apply to the per-user instance, because we never want to
permit differently privileged clients access anyway.
(The process_is_owned_by_uid() call might fail if invoked unpriv, hence
there's value in not calling it if machined runs in --user mode, it's
what makes machined actually work)
We have dropped cgroup v1 support in v258. Let's drop legacy code.
Then, we can drop 'controller' argument from cg_pid_get_path() and
cg_pidref_get_path().
Marking a whole directory tree OS image as read-only is difficult
privilege-wise, because so far we rely on the FS_IMMUTABLE_FL which is
not accessible to unpriv clients.
One fundamental place where we currently rely on marking images
read-only is for keeping pristine copies of the originally downloaded
image around, which we place in "hidden" image directories. This is
probably the most relevant usecase for the read-only flag. And moreover,
the only usecase for the hidden images are these read-only pristine
copies.
Hence, let's make this work reasonably in the unpriv case, and simply
imply the read-only flag for hidden images. This is strictly speaking a
change in behaviour, but effectively it shouldn't be, because for nspawn
containers that are executed we insist on names that are hostname
compatible, and hidden names aren't (because they start with a dot).
discover-image.[ch] largely already supports per-scope operations, let's
extend this however to also cover finding .nspawn settings files and
managing the pool dir.
Current methods take a numeric PID, but we know that is unreliable for
the usual reasons. Add variants that take a PIDFD instead, or a
PID + PIDFDID combination for remote users.
Registering a process as a machine means a caller can get machined
to send sigterm to it, and more. If an unpriv user is registering,
ensure the registered process is actually owned by the user.
Follow-up for adaff8eb35
So far, machined strictly tracked the "leader" process of a machine,
i.e. the topmost process that is actually the payload of the machine.
Its runtime also defines the runtime of the machine, and we can directly
interact with it if we need to, for example for containers to join the
namespaces, or kill it.
Let's optionally also track the "supervisor" process of a machine, i.e.
the host process that manages the payload if there is one. This is
generally useful info, but in particular is useful because we might need
to communicate with it to shutdown a machine without cooperation of the
payload. Traditionally we did this by simply stopping the unit of the
machine, but this is not doable now that the host machined can be used
to track per-user machines.
In the long run we probably want a more bespoke protocol between
machined and supervisors (so that we can execute other commands too,
such as request cooperative reboots/shutdowns), but that's for later.
Some environments call the concept "monitor" rather than "supervisor" or
use some other term. I stuck to "supervisor" because nspawn uses this,
and ultimately one name is as good as another.
And of course, in other implementations of VM managers of containers
there might not be a single process tracking each VM/container. Because
of this, the concept of a supervisor is optional.
The difference between these two operations are large: one is relatively
superficial: for "registration" all resources remain associated with the
invoking user, only the cgroup is reported to machined which then keeps
track of the machine, too. OTOH "creation" a scope is allocated in
system context, hence the invoked code will be owned by the system, and
its resource usage charged against the system.
Hence, use two distinct polkit actions for this, so that we can relax
access to registration, but keep access to creation tough.
Now that unpriv clients can register machines, let's register their UID
too. This allows us to do two things:
1. make sure the scope delegation is assigned to the right UID (so that
the unpriv user can actually create cgroups below the delegated
scope)
2. permit certain types of access (i.e. killing, or pty access) to the
client without auth if it owns the machine.
The method call already does a PK check, it was just forgotten to
allowlist this in the dbus policy. And in the dbus vtable for
OpenMachinePTY() call. (It was allowlisted in the per-machine
vtable…)
Anyway, clean this up.
Let's check the leader alive state, and let's log about dbus errors.
This mimics (but is not quite identical to) what we do these days in
logind for GC'ing user sessions.
We nowadays support unprivileged invocation of systemd-nspawn +
systemd-vmspawn, but there was no support for discovering suitable disk
images (i.e. no per-user counterpart of /var/lib/machines). Add this
now, and hook it up everywhere.
Instead of hardcoding machined's, importd's, portabled's, sysupdated's
image discovery to RUNTIME_SCOPE_SYSTEM I introduced a field that make
the scope variable, even if this field is always initialized to
RUNTIME_SCOPE_SYSTEM for now. I think these four services should
eventually be updated to support a per-user concept too, this is
preparation for that, even though it doesn't outright add support for
this.
This is for the largest part not user visible, except for in nspawn,
vmspawn and the dissect tool. For the latter I added a pair of
--user/--system switches to select the discovery scope.
This commit includes adding introduce manager_get_machine_by_pidref() as a replacement for manager_get_machine_by_pid()
and moving surrounding code to utilise PidRef.
Previously, Image objects were only cached when reading properties or
methods in the org.freedesktop.machine1.Image interface are called.
This makes that, when a method in the main interface (org.freedesktop.machine1)
for an image is called, also acquire the Image object from the cache,
and if not cached, create Image object and put into the cache, like we
do for org.freedesktop.machine1.Image.
Otherwise, if some properties of an image are updated by methods in the main
interface, e.g. MarkImageReadOnly(), the changes do not applied to the cached
Image object, and subsequent read of proerties through the interface for the
image, e.g. ReadOnly property, may provide outdated values.
Follow-up for 1ddb263d21.
Fixes#32888.
Also adds three properties:
- VsockCid: the VSOCK CID of the VM
- SshAddress: the address of the VM in a format SSH can connect to
- SshPrivateKeyPath: the path to the SSH private key to use to connect
to the VM.
GetMachineSSHInfo is essentially a convenience method to query both the
SshAddress and SshPrivateKeyPath properties at once.
This simplifies bus_verify_polkit_async() and related calls quite a bit:
1. This removes any support for authentication-by-Linux-capability. This
is ultimately a kdbus leftover: with classic AF_UNIX transports we
cannot authenticate by capabilities securely (because we cannot
acquire it from the peer without races), hence we never actually did.
Since the necessary kernel work didn't materialize in the last 10y,
and is unlikely to be added, let's just kill this context. We cannot
quite remove the caps stuff from sd-bus for API compat, but for our
polkit logic let's kill it.
2. The "good_uid" and "interactive" params are only necessary in very
few cases, hence let's move them to a new call
bus_verify_polkit_async_full() and make bus_verify_polkit_async() a
wrapper around it without those two parameters.
This also fixes a bunch of wrong uses of the "interactive" bool. The
bool makes no sense today as the ALLOW_INTERACTIVE_AUTHORIZATION field
in the D-Bus message header replaces it fully. We only need it to
implement method calls we introduced prior to that header field becoming
available in D-Bus. And it should only be used on such old method calls,
and otherwise always be set to false.
This does not change behaviour in any way. Just simplifies stuff.
Fixes: #21586
We use it for more than just pipe() arrays. For example also for
socketpair(). Hence let's give it a generic name.
Also add EBADF_TRIPLET to mirror this for things like
stdin/stdout/stderr arrays, which we use a bunch of times.
We usually check return value of syscalls or glibc functions by it is
negative or not, something like that `if (stat(path, &st) < 0)`.
Let's also use the same style for lseek() and friends even the type of
their return value is off_t.
Note, fseeko() returns int, instead of off_t.
Mike Yuan
Yu Watanabe
Daan De Meyer
Daan De Meyer
Lennart Poettering
Luca Boccassi
Ivan Kruglov
Sam Leonard