Let's make umount_verbose() more like mount_verbose_xyz(), i.e. take log
level and flags param. In particular the latter matters, since we
typically don't actually want to follow symlinks when unmounting.
Let's track the "dirty" state of a home directory backed by a LUKS
volume by setting a new xattr "home.home-dirty" on the backing file
whenever it is in use.
This allows us to later user this information to show a home directory
as "dirty". This is useful because we trim/allocate on log-out, and
if we don't do that a home directory will be larger than necessary. This
fact is something we should communicate to the admin.
The idea is that when an admin sees a user with a "dirty" home directory
they can ask them to log in, to clean up the dirty state, and thus trim
everything again.
For discussion around this see: https://pagure.io/fedora-workstation/issue/82
Recovery keys for homed are very similar to regular passwords, except
that they are exclusively generated by the computer, and not chosen by
the user. The idea is that they are printed or otherwise stored
externally and not what users type in every day.
Taking inspiration from Windows and MacOS this uses 256bit keys. We
format them in 64 yubikey modhex characters, in groups of 8 chars
separated by dashes.
Why yubikey modhex? modhex only uses characters that are are located at
the same place in western keyboard designs. This should reduce the
chance for incorrect inputs for a major chunk of our users, though
certainly not all. This is particular relevant during early boot and
recovery situations, where there's a good chance the keyboard mapping is
not correctly set up.
homed maintains two or three copies of the user's identity record per
home directory: one on the host, one inside the LUKS header, and one
embedded in the home directory.
Previously we'd insist that if a user logs in they have to authenticate
against all three, as a safety feature. This broke logging into
unfixated records however, since in that case the host version is
synthetic and thus does not carry any authentication data.
Let's hence losen the strictness here: accept authentication against
host records that carry no auth data. This should be safe as we know
after all that the second/third record will catch invalid accesses.
Fixes: #15178
Let's make the logic a bit smarter: if we detect that /home is
encrypted, let's avoid double encryption and prefer plain
directory/subvolumes instead of our regular luks images.
Also, allow configuration go storage/file system via an env var passed
to homework. In a later commit, let's then change homed to initialize
that env var from a config file setting, when invoking homework.
Make use of the new user_record_build_image_path() helper the previous
commit added to share some code.
Also, let's make sure we update all parsed-out fields with the new data
from the binding, so that the parsed-out fields are definitely
up-to-date.
