nixpkgs/nixos/modules/config/users-groups.nix
Eelco Dolstra 1a75958be5 Unify mutableUsers = { true, false }
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.
2014-08-15 02:15:29 +02:00

380 lines
12 KiB
Nix

{ config, lib, pkgs, ... }:
with lib;
let
ids = config.ids;
cfg = config.users;
passwordDescription = ''
The options <literal>hashedPassword</literal>,
<literal>password</literal> and <literal>passwordFile</literal>
controls what password is set for the user.
<literal>hashedPassword</literal> overrides both
<literal>password</literal> and <literal>passwordFile</literal>.
<literal>password</literal> overrides <literal>passwordFile</literal>.
If none of these three options are set, no password is assigned to
the user, and the user will not be able to do password logins.
If the option <literal>users.mutableUsers</literal> is true, the
password defined in one of the three options will only be set when
the user is created for the first time. After that, you are free to
change the password with the ordinary user management commands. If
<literal>users.mutableUsers</literal> is false, you cannot change
user passwords, they will always be set according to the password
options.
'';
userOpts = { name, config, ... }: {
options = {
name = mkOption {
type = types.str;
description = ''
The name of the user account. If undefined, the name of the
attribute set will be used.
'';
};
description = mkOption {
type = types.str;
default = "";
example = "Alice Q. User";
description = ''
A short description of the user account, typically the
user's full name. This is actually the GECOS or comment
field in <filename>/etc/passwd</filename>.
'';
};
uid = mkOption {
type = with types; nullOr int;
default = null;
description = ''
The account UID. If the UID is null, a free UID is picked on
activation.
'';
};
isSystemUser = mkOption {
type = types.bool;
default = false;
description = ''
Indicates if the user is a system user or not. This option
only has an effect if <option>uid</option> is
<option>null</option>, in which case it determines whether
the user's UID is allocated in the range for system users
(below 500) or in the range for normal users (starting at
1000).
'';
};
group = mkOption {
type = types.str;
default = "nogroup";
description = "The user's primary group.";
};
extraGroups = mkOption {
type = types.listOf types.str;
default = [];
description = "The user's auxiliary groups.";
};
home = mkOption {
type = types.str;
default = "/var/empty";
description = "The user's home directory.";
};
shell = mkOption {
type = types.str;
default = "/run/current-system/sw/sbin/nologin";
description = "The path to the user's shell.";
};
createHome = mkOption {
type = types.bool;
default = false;
description = ''
If true, the home directory will be created automatically. If this
option is true and the home directory already exists but is not
owned by the user, directory owner and group will be changed to
match the user.
'';
};
useDefaultShell = mkOption {
type = types.bool;
default = false;
description = ''
If true, the user's shell will be set to
<literal>cfg.defaultUserShell</literal>.
'';
};
hashedPassword = mkOption {
type = with types; uniq (nullOr str);
default = null;
description = ''
Specifies the (hashed) password for the user.
${passwordDescription}
'';
};
password = mkOption {
type = with types; uniq (nullOr str);
default = null;
description = ''
Specifies the (clear text) password for the user.
Warning: do not set confidential information here
because it is world-readable in the Nix store. This option
should only be used for public accounts.
${passwordDescription}
'';
};
passwordFile = mkOption {
type = with types; uniq (nullOr string);
default = null;
description = ''
The path to a file that contains the user's password. The password
file is read on each system activation. The file should contain
exactly one line, which should be the password in an encrypted form
that is suitable for the <literal>chpasswd -e</literal> command.
${passwordDescription}
'';
};
};
config = {
name = mkDefault name;
shell = mkIf config.useDefaultShell (mkDefault cfg.defaultUserShell);
};
};
groupOpts = { name, config, ... }: {
options = {
name = mkOption {
type = types.str;
description = ''
The name of the group. If undefined, the name of the attribute set
will be used.
'';
};
gid = mkOption {
type = with types; nullOr int;
default = null;
description = ''
The group GID. If the GID is null, a free GID is picked on
activation.
'';
};
members = mkOption {
type = with types; listOf string;
default = [];
description = ''
The user names of the group members, added to the
<literal>/etc/group</literal> file.
'';
};
};
config = {
name = mkDefault name;
};
};
idsAreUnique = set: idAttr: !(fold (name: args@{ dup, acc }:
let
id = builtins.toString (builtins.getAttr idAttr (builtins.getAttr name set));
exists = builtins.hasAttr id acc;
newAcc = acc // (builtins.listToAttrs [ { name = id; value = true; } ]);
in if dup then args else if exists
then builtins.trace "Duplicate ${idAttr} ${id}" { dup = true; acc = null; }
else { dup = false; acc = newAcc; }
) { dup = false; acc = {}; } (builtins.attrNames set)).dup;
uidsAreUnique = idsAreUnique (filterAttrs (n: u: u.uid != null) cfg.extraUsers) "uid";
gidsAreUnique = idsAreUnique (filterAttrs (n: g: g.gid != null) cfg.extraGroups) "gid";
spec = builtins.toFile "users-groups.json" (builtins.toJSON {
inherit (cfg) mutableUsers;
users = mapAttrsToList (n: u:
{ inherit (u)
name uid group description home shell createHome isSystemUser
password passwordFile hashedPassword;
}) cfg.extraUsers;
groups = mapAttrsToList (n: g:
{ inherit (g) name gid;
members = mapAttrsToList (n: u: u.name) (
filterAttrs (n: u: elem g.name u.extraGroups) cfg.extraUsers
);
}) cfg.extraGroups;
});
in {
###### interface
options = {
users.mutableUsers = mkOption {
type = types.bool;
default = true;
description = ''
If true, you are free to add new users and groups to the system
with the ordinary <literal>useradd</literal> and
<literal>groupadd</literal> commands. On system activation, the
existing contents of the <literal>/etc/passwd</literal> and
<literal>/etc/group</literal> files will be merged with the
contents generated from the <literal>users.extraUsers</literal> and
<literal>users.extraGroups</literal> options. If
<literal>mutableUsers</literal> is false, the contents of the user and
group files will simply be replaced on system activation. This also
holds for the user passwords; if this option is false, all changed
passwords will be reset according to the
<literal>users.extraUsers</literal> configuration on activation. If
this option is true, the initial password for a user will be set
according to <literal>users.extraUsers</literal>, but existing passwords
will not be changed.
'';
};
users.enforceIdUniqueness = mkOption {
type = types.bool;
default = true;
description = ''
Whether to require that no two users/groups share the same uid/gid.
'';
};
users.extraUsers = mkOption {
default = {};
type = types.loaOf types.optionSet;
example = {
alice = {
uid = 1234;
description = "Alice Q. User";
home = "/home/alice";
createHome = true;
group = "users";
extraGroups = ["wheel"];
shell = "/bin/sh";
};
};
description = ''
Additional user accounts to be created automatically by the system.
This can also be used to set options for root.
'';
options = [ userOpts ];
};
users.extraGroups = mkOption {
default = {};
example =
{ students.gid = 1001;
hackers = { };
};
type = types.loaOf types.optionSet;
description = ''
Additional groups to be created automatically by the system.
'';
options = [ groupOpts ];
};
security.initialRootPassword = mkOption {
type = types.str;
default = "!";
example = "";
description = ''
The (hashed) password for the root account set on initial
installation. The empty string denotes that root can login
locally without a password (but not via remote services such
as SSH, or indirectly via <command>su</command> or
<command>sudo</command>). The string <literal>!</literal>
prevents root from logging in using a password.
Note that setting this option sets
<literal>users.extraUsers.root.hashedPassword</literal>.
Also, if <literal>users.mutableUsers</literal> is false
you cannot change the root password manually, so in that case
the name of this option is a bit misleading, since it will define
the root password beyond the user initialisation phase.
'';
};
};
###### implementation
config = {
users.extraUsers = {
root = {
uid = ids.uids.root;
description = "System administrator";
home = "/root";
shell = cfg.defaultUserShell;
group = "root";
extraGroups = [ "grsecurity" ];
hashedPassword = mkDefault config.security.initialRootPassword;
};
nobody = {
uid = ids.uids.nobody;
description = "Unprivileged account (don't use!)";
group = "nogroup";
};
};
users.extraGroups = {
root.gid = ids.gids.root;
wheel.gid = ids.gids.wheel;
disk.gid = ids.gids.disk;
kmem.gid = ids.gids.kmem;
tty.gid = ids.gids.tty;
floppy.gid = ids.gids.floppy;
uucp.gid = ids.gids.uucp;
lp.gid = ids.gids.lp;
cdrom.gid = ids.gids.cdrom;
tape.gid = ids.gids.tape;
audio.gid = ids.gids.audio;
video.gid = ids.gids.video;
dialout.gid = ids.gids.dialout;
nogroup.gid = ids.gids.nogroup;
users.gid = ids.gids.users;
nixbld.gid = ids.gids.nixbld;
utmp.gid = ids.gids.utmp;
adm.gid = ids.gids.adm;
grsecurity.gid = ids.gids.grsecurity;
};
system.activationScripts.users = stringAfter [ "etc" ]
''
${pkgs.perl}/bin/perl -w \
-I${pkgs.perlPackages.FileSlurp}/lib/perl5/site_perl \
-I${pkgs.perlPackages.JSON}/lib/perl5/site_perl \
${./update-users-groups.pl} ${spec}
'';
# for backwards compatibility
system.activationScripts.groups = stringAfter [ "users" ] "";
assertions = [
{ assertion = !cfg.enforceIdUniqueness || (uidsAreUnique && gidsAreUnique);
message = "UIDs and GIDs must be unique!";
}
];
};
}