Ubuntu Manpage: org.freedesktop.home1 - The D-Bus interface of systemd-homed

Provided by: systemd-homed_255.4-1ubuntu8.4_amd64

NAME

       org.freedesktop.home1 - The D-Bus interface of systemd-homed

INTRODUCTION

       systemd-homed.service(8) is a system service which may be used to create, remove, change
       or inspect home areas. This page describes the D-Bus interface.

THE MANAGER OBJECT

The service exposes the following interfaces on the Manager object on the bus:

node /org/freedesktop/home1 {
interface org.freedesktop.home1.Manager {
methods:
GetHomeByName(in s user_name,
out u uid,
out s home_state,
out u gid,
out s real_name,
out s home_directory,
out s shell,
out o bus_path);
GetHomeByUID(in u uid,
out s user_name,
out s home_state,
out u gid,
out s real_name,
out s home_directory,
out s shell,
out o bus_path);
GetUserRecordByName(in s user_name,
out s user_record,
out b incomplete,
out o bus_path);
GetUserRecordByUID(in u uid,
out s user_record,
out b incomplete,
out o bus_path);
ListHomes(out a(susussso) home_areas);
@org.freedesktop.systemd1.Privileged("true")
ActivateHome(in s user_name,
in s secret);
@org.freedesktop.systemd1.Privileged("true")
DeactivateHome(in s user_name);
RegisterHome(in s user_record);
UnregisterHome(in s user_name);
CreateHome(in s user_record);
RealizeHome(in s user_name,
in s secret);
RemoveHome(in s user_name);
@org.freedesktop.systemd1.Privileged("true")
FixateHome(in s user_name,
in s secret);
AuthenticateHome(in s user_name,
in s secret);
UpdateHome(in s user_record);
ResizeHome(in s user_name,
in t size,
in s secret);
ChangePasswordHome(in s user_name,
in s new_secret,
in s old_secret);
@org.freedesktop.systemd1.Privileged("true")
LockHome(in s user_name);
@org.freedesktop.systemd1.Privileged("true")
UnlockHome(in s user_name,
in s secret);
AcquireHome(in s user_name,
in s secret,
in b please_suspend,
out h send_fd);
@org.freedesktop.systemd1.Privileged("true")
RefHome(in s user_name,
in b please_suspend,
out h send_fd);
@org.freedesktop.systemd1.Privileged("true")
ReleaseHome(in s user_name);
@org.freedesktop.systemd1.Privileged("true")
LockAllHomes();
@org.freedesktop.systemd1.Privileged("true")
DeactivateAllHomes();
@org.freedesktop.systemd1.Privileged("true")
Rebalance();
properties:
readonly a(sso) AutoLogin = [...];
};
interface org.freedesktop.DBus.Peer { ... };
interface org.freedesktop.DBus.Introspectable { ... };
interface org.freedesktop.DBus.Properties { ... };
};

Methods
GetHomeByName() returns basic user information (a minimal subset of the full user record),
provided a user name. The information supplied more or less matches what getpwnam(3)
returns: the numeric UID and GID, the real name, home directory and shell. In addition it
returns a state identifier describing the state the user's home directory is in, as well
as a bus path referring to the bus object encapsulating the user record and home
directory. This object implements the org.freedesktop.home1.Home interface documented
below.

GetHomeByUID() is similar to GetHomeByName() but acquires the information based on the
numeric UID of the user.

GetUserRecordByName() is also similar to GetHomeByName() but returns the full JSON user
record data instead of the broken down records. An additional returned boolean indicates
whether the record is complete or not. A record is considered complete when its
"privileged" section is included, and incomplete if it was removed (see JSON User
Records[1] for details about the various sections of a user record). Generally, only
privileged clients and clients running under the identity of the user itself get access to
the "privileged" section and will thus see complete records.

GetUserRecordByUID() is similar to GetUserRecordByName() but returns the user record
matching the specified numeric UID.

ListHomes() returns an array of all locally managed users. The array contains the same
fields GetHomeByName() returns: user name, numeric UID, state, numeric GID, real name,
home directory, shell and bus path of the matching bus object.

ActivateHome() activates (i.e. mounts) the home directory of the specified user. The
second argument shall contain a user record consisting only of a "secret" section (all
other sections should be stripped, see JSON User Records[1] for details), and should
contain only the secret credentials necessary for unlocking the home directory. Typically
a client would invoke this function first with an entirely empty record (which is possibly
sufficient if single-factor authentication with a plugged-in security token is
configured), and would then retry with a record populated with more information, depending
on the returned error code, in case more credentials are necessary. This function is
synchronous and returns only after the home directory was fully activated (or the
operation failed), which might take some time. Clients must be prepared for that, and
typically should extend the D-Bus method call timeout accordingly. This method is
equivalent to the Activate() method on the org.freedesktop.home1.Home interface documented
below, but may be called on the manager object and takes a user name as additional
argument, instead.

DeactivateHome() deactivates (i.e. unmounts) the home directory of the specified user. It
is equivalent to the Deactivate() method on the org.freedesktop.home1.Home interface
documented below.

RegisterHome() registers a new home directory locally. It receives the JSON user record as
only argument (which typically excludes the "secret" section). Registering a home
directory just makes the user record known to the system, it does not create a home
directory or such (which is expected to exist already, or created later). This operation
is useful to register home directories locally that are not located where
systemd-homed.service would find them automatically.

UnregisterHome() unregisters an existing home directory. It takes a user name as argument
and undoes what RegisterHome() does. It does not attempt to remove the home directory
itself, it just unregisters it with the local system. Note that if the home directory is
placed where systemd-homed.service looks for home directories anyway this call will only
undo fixation (see below), but the record will remain known to systemd-homed.service and
be listed among known records. Since the user record is embedded into the home directory
this operation generally does not discard data belonging to the user or their record. This
method is equivalent to Unregister() on the org.freedesktop.home1.Home interface.

CreateHome() registers and creates a new home directory. This takes a fully specified JSON
user record as argument (including the "secret" section). This registers the user record
locally and creates a home directory matching it, depending on the settings specified in
the record in combination with local configuration.

RealizeHome() creates a home directory whose user record is already registered locally.
This takes a user name plus a user record consisting only of the "secret" section.
Invoking RegisterHome() followed by RealizeHome() is mostly equivalent to calling
CreateHome(), except that the latter combines the two in atomic fashion. This method is
equivalent to Realize() on the org.freedesktop.home1.Home interface.

RemoveHome() unregisters a user record locally, and removes the home directory belonging
to it, if it is accessible. It takes a user name as argument. This method is equivalent to
Remove() on the org.freedesktop.home1.Home interface.

FixateHome() "fixates" an automatically discovered home directory. systemd-homed.service
automatically discovers home directories dropped in our plugged in and adds them to the
runtime list of user records it manages. A user record discovered that way may be
"fixated", in which case it is copied out of the home directory, onto persistent storage,
to fixate the UID/GID assignment of the record, and extract additional (typically
previously encrypted) user record data from the home directory. A home directory mus be
fixated before it can be logged into. This method call takes a user name and a JSON user
record consisting only of the "secret" section as argument. This method is equivalent to
Fixate() on the org.freedesktop.home1.Home interface.

AuthenticateHome() checks passwords or other authentication credentials associated with
the home directory. It takes a user name and a JSON user record consisting only of the
"secret" section as argument. Note that many of the other method calls authenticate the
user first, in order to execute some other operation. This method call only authenticates
and executes no further operation. Like ActivateHome() it is usually first invoked with an
empty JSON user record, which is then populated for subsequent tries with additional
authentication data supplied. This method is equivalent to Authenticate() on the
org.freedesktop.home1.Home interface.

UpdateHome() updates a locally registered user record. Takes a fully specified JSON user
record as argument (including the "secret" section). A user with a matching name and realm
must be registered locally already, and the last change timestamp of the newly supplied
record must be newer than the previously existing user record. Note this operation updates
the user record only, it does not propagate passwords/authentication tokens from the user
record to the storage back-end, or resizes the storage back-end. Typically a home
directory is first updated, and then the password of the underlying storage updated using
ChangePasswordHome() as well as the storage resized using ResizeHome(). This method is
equivalent to Update() on the org.freedesktop.home1.Home interface.

ResizeHome() resizes the storage associated with a user record. Takes a user name, a disk
size in bytes and a user record consisting only of the "secret" section as argument. If
the size is specified as UINT64_MAX the storage is resized to the size already specified
in the user record. Typically, if the user record is updated using UpdateHome() above this
is used to propagate the size configured there-in down to the underlying storage back-end.
This method is equivalent to Resize() on the org.freedesktop.home1.Home interface.

ChangePasswordHome() changes the passwords/authentication tokens of a home directory.
Takes a user name, and two JSON user record objects, each consisting only of the "secret"
section, for the old and for the new passwords/authentication tokens. If the user record
with the new passwords/authentication token data is specified as empty the existing user
record's settings are propagated down to the home directory storage. This is typically
used after a user record is updated using UpdateHome() in order to propagate the
secrets/authentication tokens down to the storage. Background: depending on the backend
the user's authentication credentials are stored at multiple places: the user record kept
on the host, the user record kept in the home directory and the encrypted LUKS volume
slot. If the home directory is used on a different machined temporarily, and the password
is changed there, and then is moved back to the original host, the passwords of the three
might get out of sync. By issuing ChangePasswordHome() the three locations are updated to
match the newest information. This method is equivalent to ChangePassword() on the
org.freedesktop.home1.Home interface.

LockHome() temporarily suspends access to a home directory, flushing out any cryptographic
keys from memory. This is only supported on some back-ends, and usually done during system
suspend, in order to effectively secure home directories while the system is sleeping.
Takes a user name as single argument. If an application attempts to access a home
directory while it is locked it will typically freeze until the home directory is unlocked
again. This method is equivalent to Lock() on the org.freedesktop.home1.Home interface.

UnlockHome() undoes the effect of LockHome(). Takes a user name and a user record
consisting only of the "secret" section as arguments. This method is equivalent to
Unlock() on the org.freedesktop.home1.Home interface.

AcquireHome() activates or unlocks a home directory in a reference counted mode of
operation. Takes a user name and user record consisting only of "secret" section as
argument. If the home directory is not active yet, it is activated. If it is currently
locked it is unlocked. After completion a reference to the activation/unlocking of the
home directory is returned via a file descriptor. When the last client which acquired such
a file descriptor closes it the home directory is automatically deactivated again. This
method is typically invoked when a user logs in, and the file descriptor is held until the
user logs out again, thus ensuring the user's home directory can be unmounted
automatically again in a robust fashion, when the user logs out. The third argument is a
boolean which indicates whether the client invoking the call is able to automatically
re-authenticate when the system comes back from suspending. It should be set by all
clients that implement a secure lock screen running outside of the user's context, that is
brought up when the system comes back from suspend and can be used to re-acquire the
credentials to unlock the user's home directory. If a home directory has at least one
client with an open reference to the home directory that does not support this it is not
suspended automatically at system suspend, otherwise it is. This method is equivalent to
Acquire() on the org.freedesktop.home1.Home interface.

RefHome() is similar to AcquireHome() but takes no user record with "secret" section, i.e.
will take an additional reference to an already activated/unlocked home directory without
attempting to activate/unlock it itself. It will fail if the home directory is not already
activated. This method is equivalent to Ref() on the org.freedesktop.home1.Home interface.

ReleaseHome() releases a home directory again, if all file descriptors referencing it are
already closed, that where acquired through AcquireHome() or RefHome(). Note that this
call does not actually cause the deactivation of the home directory (which happens
automatically when the last referencing file descriptor is closed), but is simply a
synchronization mechanism that allows delaying of the user session's termination until any
triggered deactivation is completed. This method is equivalent to Release() on the
org.freedesktop.home1.Home interface.

LockAllHomes() locks all active home directories that only have references that opted into
automatic suspending during system suspend. This is usually invoked automatically shortly
before system suspend.

DeactivateAllHomes() deactivates all home areas that are currently active. This is usually
invoked automatically shortly before system shutdown.

Rebalance() synchronously rebalances free disk space between home areas. This only
executes an operation if at least one home area using the LUKS2 backend is active and has
rebalancing enabled, and is otherwise a NOP.

Properties
AutoLogin exposes an array of structures consisting of user name, seat name and object
path of an home directory object. All locally managed users that have the "autoLogin"
field set are listed here, with the seat name they are associated with. A display manager
may watch this property and pre-fill the login screen with the users exposed this way.

THE HOME OBJECT

           node /org/freedesktop/home1/home {
             interface org.freedesktop.home1.Home {
               methods:
                 @org.freedesktop.systemd1.Privileged("true")
                 Activate(in  s secret);
                 @org.freedesktop.systemd1.Privileged("true")
                 Deactivate();
                 Unregister();
                 Realize(in  s secret);
                 Remove();
                 @org.freedesktop.systemd1.Privileged("true")
                 Fixate(in  s secret);
                 Authenticate(in  s secret);
                 Update(in  s user_record);
                 Resize(in  t size,
                        in  s secret);
                 ChangePassword(in  s new_secret,
                                in  s old_secret);
                 @org.freedesktop.systemd1.Privileged("true")
                 Lock();
                 @org.freedesktop.systemd1.Privileged("true")
                 Unlock(in  s secret);
                 @org.freedesktop.systemd1.Privileged("true")
                 Acquire(in  s secret,
                         in  b please_suspend,
                         out h send_fd);
                 @org.freedesktop.systemd1.Privileged("true")
                 Ref(in  b please_suspend,
                     out h send_fd);
                 @org.freedesktop.systemd1.Privileged("true")
                 Release();
               properties:
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
                 readonly s UserName = '...';
                 readonly u UID = ...;
                 readonly (suusss) UnixRecord = ...;
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
                 readonly s State = '...';
                 @org.freedesktop.DBus.Property.EmitsChangedSignal("invalidates")
                 readonly (sb) UserRecord = ...;
             };
             interface org.freedesktop.DBus.Peer { ... };
             interface org.freedesktop.DBus.Introspectable { ... };
             interface org.freedesktop.DBus.Properties { ... };
             interface org.freedesktop.DBus.ObjectManager { ... };
           };

   Methods
       Activate(), Deactivate(), Unregister(), Realize(), Remove(), Fixate(), Authenticate(),
       Update(), Resize(), ChangePassword(), Lock(), Unlock(), Acquire(), Ref(), Release()
       operate like their matching counterparts on the org.freedesktop.home1.Manager interface
       (see above). The main difference is that they are methods of the home directory objects,
       and hence carry no additional user name parameter. Which of the two flavors of methods to
       call depends on the handles to the user known on the client side: if only the user name is
       known, it's preferable to use the methods on the manager object since they operate with
       user names only. If however the home object path was already acquired some way it is
       preferable to operate on the org.freedesktop.home1.Home objects instead.

   Properties
       UserName contains the user name of the user account/home directory.

       UID contains the numeric UNIX UID of the user account.

       UnixRecord contains a structure encapsulating the six fields a struct passwd typically
       contains (the password field is suppressed).

       State exposes the current state home the home directory.

       UserRecord contains the full JSON user record string of the user account.

VERSIONING

       These D-Bus interfaces follow the usual interface versioning guidelines[2].

NOTES