Previously we allocated subuids automatically for all normal users.
Make this explicitly configurable, so that one can use this for system
users too (or explicitly disable for normal users). Also don't allocate
automatically by default if a user already has ranges specified statically.
configuration.nix(1) states
users.extraUsers.<name>.createHome
[...] If [...] the home directory already exists but is not
owned by the user, directory owner and group will be changed to
match the user.
i.e. ownership would change only if the user mismatched; the code
however ignores the owner, it is sufficient to enable `createHome`:
if ($u->{createHome}) {
make_path($u->{home}, { mode => 0700 }) if ! -e $u->{home};
chown $u->{uid}, $u->{gid}, $u->{home};
}
Furthermore, permissions are ignored on already existing directories and
therefore may allow others to read private data eventually.
Given that createHome already acts as switch to not only create but
effectively own the home directory, manage permissions in the same
manner to ensure the intended default and cover all primary attributes.
Avoid yet another configuration option to have administrators make a
clear and simple choice between securely managing home directories
and optionally defering management to own code (taking care of custom
location, ownership, mode, extended attributes, etc.).
While here, simplify and thereby fix misleading documentation.
Having the .tmp suffix is broken w.r.t. to multiple writers,
as they would overwrite existing files. using the atomic flag
will make write_file to create a unique temporary file it gets renamed
to its target.
This is required by (among others) Podman to run containers in rootless mode.
Other distributions such as Fedora and Ubuntu already set up these mappings.
The scheme with a start UID/GID offset starting at 100000 and increasing in 65536 increments is copied from Fedora.
This enlarges the system uid/gid range 6-fold, from 100 to 600 ids. This
is a preventative measure against running out of dynamically allocated
ids for NixOS services with isSystemUser, which should become the
preferred way of allocating uids for non-real users.
We don’t want any trailing whitespace, otherwise we mess up the
formating of the shadow file. Some things like readFile may have the
trailing new line.
Fixes#66745
I want to manage users centrally via declarativeUsers,
but allow users to change their shell as they please,
similar to how they can change passwords at will
if none of the password-related NixOS settings are set for their user.
When a user or group is revived, this allows it to be allocated the
UID/GID it had before.
A consequence is that UIDs and GIDs are no longer reused.
Fixes#24010.
Verified that following nixos configuration:
users.users.foo = {
uid = 1000;
name = "foo";
};
users.users.bar = {
name = "bar";
};
Before this commit both users will get uid of 1000, after it's applied
bar will correctly get 1001.
Instead of showing this output from "nixos-rebuild switch":
warning: not applying GID change of group ‘munin’
warning: not applying UID change of user ‘ntp’
print this:
warning: not applying GID change of group ‘munin’ (95 -> 102)
warning: not applying UID change of user ‘ntp’ (3 -> 179)
This makes it possible for users to take action and fixup the UIDs/GIDs
that NixOS won't touch.
Perl seems to write the file in latin1 independent of the actual input
encoding. This can corrupt the "description" field of /etc/passwd. By
setting "binmode" to ":utf8" Perl can be forced to write UTF-8. Ideally
the program would simply read/write the fields by value without any
changes in encoding. However, assuming/enforcing UTF-8 is a lot better
than using an obsolete coding like latin1.
I.e. don't call "passwd" to update /etc/shadow from the "password"
option. This has the side-effect of not updating the password if
mutableUsers = true (since the code path for "hashedPassword" has a
check for mutableUsers).
Fixes#4747.
With mutableUsers = true, we now ensure that all users and groups that
were created declaratively, are updated or removed
appropriately. Thus, adding a user to users.extraUsers and then
removing it now causes the acoount to be removed from
/etc/passwd. Thus user/group management is fully congruent except that
users and groups that were created imperatively (via useradd/groupadd)
are not touched. We distinguish between declarative and imperative
users/groups by tracking the former in
/var/lib/nixos/declarative-{groups,users}.
With mutableUsers = false, you are now no longer required to specify
UIDs/GIDs for all users. The handling of mutableUsers = true/false is
the same code path; the only difference is that the "false" mode
ignores the existing contents of /etc/{passwd,group}.
The attribute ‘createUser’ is gone. It doesn't really make sense to
specify users that shouldn't be created.
