ORG.FREEDESKTOP.HOME1(5)

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);
          ActivateHome(in  s user_name,
                       in  s secret);
          ActivateHomeIfReferenced(in  s user_name,
                                   in  s secret);
          @org.freedesktop.systemd1.Privileged("true")
          DeactivateHome(in  s user_name);
          RegisterHome(in  s user_record);
          AdoptHome(in  s image_path,
                    in  t flags);
          UnregisterHome(in  s user_name);
          CreateHome(in  s user_record);
          CreateHomeEx(in  s user_record,
                       in  a{sh} blobs,
                       in  t flags);
          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);
          UpdateHomeEx(in  s user_record,
                       in  a{sh} blobs,
                       in  t flags);
          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")
          RefHomeUnrestricted(in  s user_name,
                              in  b please_suspend,
                              out h send_fd);
          @org.freedesktop.systemd1.Privileged("true")
          ReleaseHome(in  s user_name);
          ListSigningKeys(out a(sst) keys);
          GetSigningKey(in  s name,
                        out s der,
                        out t flags);
          AddSigningKey(in  s name,
                        in  s pem,
                        in  t flags);
          RemoveSigningKey(in  s name,
                           in  t flags);
          @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. This method, and most others in this interface that take user names, will try to use the caller's home area if the specified user name is an empty string.

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.

ActivateHomeIfReferenced() is identical to ActivateHome(). However, the call only succeeds if the home directory is currently referenced. Useful in conjunction with RefHomeUnrestricted(), which allows creating a reference to a home directory even if the home directory is not active.

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.

AdoptHome() also registers a new home directory locally. It takes a path to a home directory itself, and will register it locally. This only works for *.home and *.homedir/ home directories. This operation is done automatically for all such home areas showing up in /home/, but may be requested explicitly with this call for directories elsewhere. The flags must be set to zero, currently.

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.

CreateHomeEx() is like CreateHome(), but it allows the home directory to be created with a pre-populated blob directory (see User Record Blob Directories[2] for more info). This can be done via the dictionary passed as the blobs argument to this method: the values are open file descriptors to regular files, and the keys are the filenames that should contain their respective file's data in the blob directory. Note that for security reasons, the file descriptors passed into this method must have enough privileges to read their target file and thus cannot be "O_PATH"; this is done to ensure the caller is actually permitted to read the file they are asking to publish in the blob directories. If the user record passed as the first argument contains a "blobManifest" field it will be enforced; otherwise, a "blobManifest" field will be generated and inserted into the record. The flags argument may be used for future expansion, but for now pass 0.

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 (possibly 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.

UpdateHomeEx() is like UpdateHome(), but it allows for changes to the blob directory (see User Record Blob Directories[2] for more info). The blobs argument works in the same way as CreateHomeEx(), so check there for details. The new blob directory contents passed into this method will completely replace the user's existing blob directory. The flags argument can be used to further customize the behavior of this method via flags defined as follows:

    #define SD_HOMED_UPDATE_OFFLINE (UINT64_C(1) << 0)

When SD_HOMED_UPDATE_OFFLINE (0x01) is set, no attempt is made to update the copies of the user record and blob directory that are embedded into the home directory. Changes will be stored, however, and may be propagated into the home directory the next time it is reconciled (most likely when the user next logs in). Note that any changes made with this flag set may be lost if the home area has a newer record, which can happen if the home area is updated on another machine after this method call. This method is equivalent to UpdateEx() 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 optionally a user record consisting only of the "secret" section as arguments. 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 is 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.

RefHomeUnrestricted() is identical to RefHome() but succeeds even if the home area is not active currently. This is useful on conjunction with ActivateHomeIfReferenced().

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.

ListSigningKeys() acquires a list of installed home area signing keys. Returns an array of key names with their PEM encoded public key data. Each entry also comes with a flags value which is currently unused and should be ignored by clients.

GetSigningKey() acquires the PEM encoded public part of the specified home area signing key of the specified name. Also returns a currently unused flags value that should be ignored. The flags parameter must be set to zero, currently.

AddSigningKey() adds a new key to the list of home area signing keys. Takes a name string (free-form, suitable as filename, with suffix ".public"), the PEM encoded public key data and a currently unused flags value that must be zero. The flags parameter must be set to zero, currently.

RemoveSigningKey() removes a key from the list of home area signing keys. Takes the name of the key to remove and a currently unused flags value that must be zero. The flags parameter must be set to zero, currently.

  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:
          Activate(in  s secret);
          ActivateIfReferenced(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);
          UpdateEx(in  s user_record,
                   in  a{sh} blobs,
                   in  t flags);
          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")
          RefUnrestricted(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(), ActivateIfReferenced(), Deactivate(), Unregister(), Realize(), Remove(), Fixate(), Authenticate(), Update(), UpdateEx(), Resize(), ChangePassword(), Lock(), Unlock(), Acquire(), Ref(), RefUnrestricted(), 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 is preferable to use the methods on the manager object since they operate with user names only. Clients can also easily operate on their own home area by using the methods on the manager object with an empty string as the user name. If the client has the home's object path already acquired in some way, however, 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[3].

HISTORY

  The Manager Object

ActivateHomeIfReferenced(), RefHomeUnrestricted(), CreateHomeEx(), and UpdateHomeEx() were added in version 256.

AdoptHome(), ListSigningKeys(), GetSigningKey(), AddSigningKey(), and RemoveSigningKey() were added in version 258.

  Home Objects

ActivateIfReferenced(), RefUnrestricted(), and UpdateEx() were added in version 256.

SEE ALSO

systemd(1), systemd-homed.service(8), homectl(1)

NOTES

1.  JSON User Records
    https://systemd.io/USER_RECORD

2.  User Record Blob Directories
    https://systemd.io/USER_RECORD_BLOB_DIRS

3.  the usual interface versioning guidelines
    https://0pointer.de/blog/projects/versioning-dbus.html