99ba1cb424
With #36556, a check was introduced to make sure the user and group names do not exceed their respective maximum length. This is in part because systemd also enforces that length, but only at runtime. So in general it's a good idea to catch as much as we can during evaluation time, however the maximum length of the group name was set to 16 characters according groupadd(8). The maximum length of the group names however is a compile-time option and even systemd allows more than 16 characters. In the mentioned pull request (#36556) there was already a report that this has broken evaluation for people out there. I have also checked what other distributions are doing and they set the length to either 31 characters or 32 characters, the latter being more common. Unfortunately there is a difference between the maximum length enforced by the shadow package and systemd, both for user name lengths and group name lengths. However, systemd enforces both length to have a maximum of 31 characters and I'm not sure if this is intended or just a off-by-one error in systemd. Nevertheless, I choose 32 characters simply to bring it in par with the maximum user name length. For the NixOS assertion however, I use a maximum length of 31 to make sure that nobody accidentally creates services that contain group names that systemd considers invalid because of a length of 32 characters. Signed-off-by: aszlig <aszlig@nix.build> Closes: #38548 Cc: @vcunat, @fpletz, @qknight
596 lines
19 KiB
Nix
596 lines
19 KiB
Nix
{ config, lib, utils, pkgs, ... }:
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with lib;
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let
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ids = config.ids;
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cfg = config.users;
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passwordDescription = ''
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The options <option>hashedPassword</option>,
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<option>password</option> and <option>passwordFile</option>
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controls what password is set for the user.
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<option>hashedPassword</option> overrides both
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<option>password</option> and <option>passwordFile</option>.
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<option>password</option> overrides <option>passwordFile</option>.
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If none of these three options are set, no password is assigned to
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the user, and the user will not be able to do password logins.
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If the option <option>users.mutableUsers</option> is true, the
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password defined in one of the three options will only be set when
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the user is created for the first time. After that, you are free to
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change the password with the ordinary user management commands. If
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<option>users.mutableUsers</option> is false, you cannot change
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user passwords, they will always be set according to the password
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options.
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'';
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hashedPasswordDescription = ''
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To generate hashed password install <literal>mkpasswd</literal>
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package and run <literal>mkpasswd -m sha-512</literal>.
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'';
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userOpts = { name, config, ... }: {
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options = {
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name = mkOption {
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type = types.str;
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apply = x: assert (builtins.stringLength x < 32 || abort "Username '${x}' is longer than 31 characters which is not allowed!"); x;
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description = ''
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The name of the user account. If undefined, the name of the
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attribute set will be used.
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'';
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};
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description = mkOption {
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type = types.str;
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default = "";
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example = "Alice Q. User";
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description = ''
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A short description of the user account, typically the
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user's full name. This is actually the “GECOS” or “comment”
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field in <filename>/etc/passwd</filename>.
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'';
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};
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uid = mkOption {
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type = with types; nullOr int;
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default = null;
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description = ''
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The account UID. If the UID is null, a free UID is picked on
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activation.
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'';
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};
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isSystemUser = mkOption {
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type = types.bool;
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default = false;
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description = ''
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Indicates if the user is a system user or not. This option
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only has an effect if <option>uid</option> is
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<option>null</option>, in which case it determines whether
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the user's UID is allocated in the range for system users
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(below 500) or in the range for normal users (starting at
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1000).
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'';
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};
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isNormalUser = mkOption {
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type = types.bool;
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default = false;
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description = ''
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Indicates whether this is an account for a “real” user. This
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automatically sets <option>group</option> to
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<literal>users</literal>, <option>createHome</option> to
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<literal>true</literal>, <option>home</option> to
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<filename>/home/<replaceable>username</replaceable></filename>,
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<option>useDefaultShell</option> to <literal>true</literal>,
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and <option>isSystemUser</option> to
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<literal>false</literal>.
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'';
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};
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group = mkOption {
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type = types.str;
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apply = x: assert (builtins.stringLength x < 32 || abort "Group name '${x}' is longer than 31 characters which is not allowed!"); x;
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default = "nogroup";
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description = "The user's primary group.";
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};
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extraGroups = mkOption {
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type = types.listOf types.str;
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default = [];
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description = "The user's auxiliary groups.";
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};
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home = mkOption {
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type = types.path;
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default = "/var/empty";
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description = "The user's home directory.";
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};
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cryptHomeLuks = mkOption {
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type = with types; nullOr str;
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default = null;
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description = ''
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Path to encrypted luks device that contains
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the user's home directory.
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'';
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};
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shell = mkOption {
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type = types.either types.shellPackage types.path;
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default = pkgs.nologin;
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defaultText = "pkgs.nologin";
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example = literalExample "pkgs.bashInteractive";
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description = ''
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The path to the user's shell. Can use shell derivations,
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like <literal>pkgs.bashInteractive</literal>. Don’t
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forget to enable your shell in
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<literal>programs</literal> if necessary,
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like <code>programs.zsh.enable = true;</code>.
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'';
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};
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subUidRanges = mkOption {
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type = with types; listOf (submodule subordinateUidRange);
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default = [];
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example = [
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{ startUid = 1000; count = 1; }
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{ startUid = 100001; count = 65534; }
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];
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description = ''
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Subordinate user ids that user is allowed to use.
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They are set into <filename>/etc/subuid</filename> and are used
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by <literal>newuidmap</literal> for user namespaces.
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'';
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};
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subGidRanges = mkOption {
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type = with types; listOf (submodule subordinateGidRange);
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default = [];
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example = [
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{ startGid = 100; count = 1; }
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{ startGid = 1001; count = 999; }
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];
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description = ''
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Subordinate group ids that user is allowed to use.
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They are set into <filename>/etc/subgid</filename> and are used
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by <literal>newgidmap</literal> for user namespaces.
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'';
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};
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createHome = mkOption {
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type = types.bool;
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default = false;
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description = ''
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If true, the home directory will be created automatically. If this
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option is true and the home directory already exists but is not
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owned by the user, directory owner and group will be changed to
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match the user.
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'';
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};
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useDefaultShell = mkOption {
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type = types.bool;
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default = false;
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description = ''
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If true, the user's shell will be set to
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<option>users.defaultUserShell</option>.
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'';
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};
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hashedPassword = mkOption {
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type = with types; uniq (nullOr str);
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default = null;
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description = ''
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Specifies the hashed password for the user.
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${passwordDescription}
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${hashedPasswordDescription}
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'';
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};
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password = mkOption {
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type = with types; uniq (nullOr str);
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default = null;
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description = ''
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Specifies the (clear text) password for the user.
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Warning: do not set confidential information here
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because it is world-readable in the Nix store. This option
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should only be used for public accounts.
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${passwordDescription}
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'';
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};
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passwordFile = mkOption {
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type = with types; uniq (nullOr string);
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default = null;
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description = ''
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The full path to a file that contains the user's password. The password
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file is read on each system activation. The file should contain
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exactly one line, which should be the password in an encrypted form
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that is suitable for the <literal>chpasswd -e</literal> command.
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${passwordDescription}
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'';
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};
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initialHashedPassword = mkOption {
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type = with types; uniq (nullOr str);
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default = null;
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description = ''
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Specifies the initial hashed password for the user, i.e. the
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hashed password assigned if the user does not already
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exist. If <option>users.mutableUsers</option> is true, the
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password can be changed subsequently using the
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<command>passwd</command> command. Otherwise, it's
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equivalent to setting the <option>hashedPassword</option> option.
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${hashedPasswordDescription}
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'';
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};
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initialPassword = mkOption {
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type = with types; uniq (nullOr str);
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default = null;
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description = ''
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Specifies the initial password for the user, i.e. the
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password assigned if the user does not already exist. If
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<option>users.mutableUsers</option> is true, the password
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can be changed subsequently using the
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<command>passwd</command> command. Otherwise, it's
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equivalent to setting the <option>password</option>
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option. The same caveat applies: the password specified here
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is world-readable in the Nix store, so it should only be
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used for guest accounts or passwords that will be changed
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promptly.
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'';
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};
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packages = mkOption {
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type = types.listOf types.package;
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default = [];
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example = literalExample "[ pkgs.firefox pkgs.thunderbird ]";
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description = ''
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The set of packages that should be made availabe to the user.
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This is in contrast to <option>environment.systemPackages</option>,
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which adds packages to all users.
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'';
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};
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};
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config = mkMerge
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[ { name = mkDefault name;
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shell = mkIf config.useDefaultShell (mkDefault cfg.defaultUserShell);
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}
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(mkIf config.isNormalUser {
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group = mkDefault "users";
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createHome = mkDefault true;
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home = mkDefault "/home/${name}";
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useDefaultShell = mkDefault true;
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isSystemUser = mkDefault false;
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})
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# If !mutableUsers, setting ‘initialPassword’ is equivalent to
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# setting ‘password’ (and similarly for hashed passwords).
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(mkIf (!cfg.mutableUsers && config.initialPassword != null) {
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password = mkDefault config.initialPassword;
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})
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(mkIf (!cfg.mutableUsers && config.initialHashedPassword != null) {
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hashedPassword = mkDefault config.initialHashedPassword;
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})
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];
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};
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groupOpts = { name, config, ... }: {
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options = {
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name = mkOption {
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type = types.str;
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description = ''
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The name of the group. If undefined, the name of the attribute set
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will be used.
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'';
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};
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gid = mkOption {
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type = with types; nullOr int;
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default = null;
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description = ''
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The group GID. If the GID is null, a free GID is picked on
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activation.
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'';
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};
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members = mkOption {
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type = with types; listOf string;
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default = [];
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description = ''
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The user names of the group members, added to the
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<literal>/etc/group</literal> file.
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'';
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};
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};
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config = {
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name = mkDefault name;
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};
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};
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subordinateUidRange = {
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options = {
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startUid = mkOption {
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type = types.int;
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description = ''
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Start of the range of subordinate user ids that user is
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allowed to use.
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'';
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};
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count = mkOption {
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type = types.int;
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default = 1;
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description = ''Count of subordinate user ids'';
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};
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};
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};
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subordinateGidRange = {
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options = {
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startGid = mkOption {
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type = types.int;
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description = ''
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Start of the range of subordinate group ids that user is
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allowed to use.
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'';
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};
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count = mkOption {
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type = types.int;
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default = 1;
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description = ''Count of subordinate group ids'';
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};
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};
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};
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mkSubuidEntry = user: concatStrings (
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map (range: "${user.name}:${toString range.startUid}:${toString range.count}\n")
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user.subUidRanges);
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subuidFile = concatStrings (map mkSubuidEntry (attrValues cfg.users));
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mkSubgidEntry = user: concatStrings (
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map (range: "${user.name}:${toString range.startGid}:${toString range.count}\n")
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user.subGidRanges);
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subgidFile = concatStrings (map mkSubgidEntry (attrValues cfg.users));
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idsAreUnique = set: idAttr: !(fold (name: args@{ dup, acc }:
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let
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id = builtins.toString (builtins.getAttr idAttr (builtins.getAttr name set));
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exists = builtins.hasAttr id acc;
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newAcc = acc // (builtins.listToAttrs [ { name = id; value = true; } ]);
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in if dup then args else if exists
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then builtins.trace "Duplicate ${idAttr} ${id}" { dup = true; acc = null; }
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else { dup = false; acc = newAcc; }
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) { dup = false; acc = {}; } (builtins.attrNames set)).dup;
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uidsAreUnique = idsAreUnique (filterAttrs (n: u: u.uid != null) cfg.users) "uid";
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gidsAreUnique = idsAreUnique (filterAttrs (n: g: g.gid != null) cfg.groups) "gid";
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spec = pkgs.writeText "users-groups.json" (builtins.toJSON {
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inherit (cfg) mutableUsers;
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users = mapAttrsToList (_: u:
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{ inherit (u)
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name uid group description home createHome isSystemUser
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password passwordFile hashedPassword
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initialPassword initialHashedPassword;
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shell = utils.toShellPath u.shell;
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}) cfg.users;
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groups = mapAttrsToList (n: g:
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{ inherit (g) name gid;
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members = g.members ++ (mapAttrsToList (n: u: u.name) (
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filterAttrs (n: u: elem g.name u.extraGroups) cfg.users
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));
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}) cfg.groups;
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});
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systemShells =
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let
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shells = mapAttrsToList (_: u: u.shell) cfg.users;
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in
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filter types.shellPackage.check shells;
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in {
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###### interface
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options = {
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users.mutableUsers = mkOption {
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type = types.bool;
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default = true;
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description = ''
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If set to <literal>true</literal>, you are free to add new users and groups to the system
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with the ordinary <literal>useradd</literal> and
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<literal>groupadd</literal> commands. On system activation, the
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existing contents of the <literal>/etc/passwd</literal> and
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<literal>/etc/group</literal> files will be merged with the
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contents generated from the <literal>users.users</literal> and
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<literal>users.groups</literal> options.
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The initial password for a user will be set
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according to <literal>users.users</literal>, but existing passwords
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will not be changed.
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<warning><para>
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If set to <literal>false</literal>, the contents of the user and
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group files will simply be replaced on system activation. This also
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holds for the user passwords; all changed
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passwords will be reset according to the
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<literal>users.users</literal> configuration on activation.
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</para></warning>
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'';
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};
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users.enforceIdUniqueness = mkOption {
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type = types.bool;
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default = true;
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description = ''
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Whether to require that no two users/groups share the same uid/gid.
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'';
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};
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users.users = mkOption {
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default = {};
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type = with types; loaOf (submodule userOpts);
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example = {
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alice = {
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uid = 1234;
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description = "Alice Q. User";
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home = "/home/alice";
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createHome = true;
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group = "users";
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extraGroups = ["wheel"];
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shell = "/bin/sh";
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};
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};
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description = ''
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Additional user accounts to be created automatically by the system.
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This can also be used to set options for root.
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'';
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};
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users.groups = mkOption {
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default = {};
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example =
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{ students.gid = 1001;
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hackers = { };
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};
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type = with types; loaOf (submodule groupOpts);
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description = ''
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Additional groups to be created automatically by the system.
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'';
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};
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# FIXME: obsolete - will remove.
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security.initialRootPassword = mkOption {
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type = types.str;
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default = "!";
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example = "";
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visible = false;
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||
};
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|
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};
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###### implementation
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config = {
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users.users = {
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root = {
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uid = ids.uids.root;
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description = "System administrator";
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home = "/root";
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shell = mkDefault cfg.defaultUserShell;
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group = "root";
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initialHashedPassword = mkDefault config.security.initialRootPassword;
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};
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nobody = {
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uid = ids.uids.nobody;
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description = "Unprivileged account (don't use!)";
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group = "nogroup";
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};
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};
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users.groups = {
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root.gid = ids.gids.root;
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wheel.gid = ids.gids.wheel;
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disk.gid = ids.gids.disk;
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kmem.gid = ids.gids.kmem;
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tty.gid = ids.gids.tty;
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||
floppy.gid = ids.gids.floppy;
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||
uucp.gid = ids.gids.uucp;
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lp.gid = ids.gids.lp;
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cdrom.gid = ids.gids.cdrom;
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tape.gid = ids.gids.tape;
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audio.gid = ids.gids.audio;
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||
video.gid = ids.gids.video;
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dialout.gid = ids.gids.dialout;
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nogroup.gid = ids.gids.nogroup;
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users.gid = ids.gids.users;
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nixbld.gid = ids.gids.nixbld;
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utmp.gid = ids.gids.utmp;
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adm.gid = ids.gids.adm;
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input.gid = ids.gids.input;
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};
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system.activationScripts.users = stringAfter [ "stdio" ]
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''
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install -m 0700 -d /root
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install -m 0755 -d /home
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|
||
${pkgs.perl}/bin/perl -w \
|
||
-I${pkgs.perlPackages.FileSlurp}/lib/perl5/site_perl \
|
||
-I${pkgs.perlPackages.JSON}/lib/perl5/site_perl \
|
||
${./update-users-groups.pl} ${spec}
|
||
'';
|
||
|
||
# for backwards compatibility
|
||
system.activationScripts.groups = stringAfter [ "users" ] "";
|
||
|
||
# Install all the user shells
|
||
environment.systemPackages = systemShells;
|
||
|
||
environment.etc = {
|
||
"subuid" = {
|
||
text = subuidFile;
|
||
mode = "0644";
|
||
};
|
||
"subgid" = {
|
||
text = subgidFile;
|
||
mode = "0644";
|
||
};
|
||
} // (mapAttrs' (name: { packages, ... }: {
|
||
name = "profiles/per-user/${name}";
|
||
value.source = pkgs.buildEnv {
|
||
name = "user-environment";
|
||
paths = packages;
|
||
inherit (config.environment) pathsToLink extraOutputsToInstall;
|
||
inherit (config.system.path) ignoreCollisions postBuild;
|
||
};
|
||
}) (filterAttrs (_: u: u.packages != []) cfg.users));
|
||
|
||
environment.profiles = [ "/etc/profiles/per-user/$USER" ];
|
||
|
||
assertions = [
|
||
{ assertion = !cfg.enforceIdUniqueness || (uidsAreUnique && gidsAreUnique);
|
||
message = "UIDs and GIDs must be unique!";
|
||
}
|
||
{ # If mutableUsers is false, to prevent users creating a
|
||
# configuration that locks them out of the system, ensure that
|
||
# there is at least one "privileged" account that has a
|
||
# password or an SSH authorized key. Privileged accounts are
|
||
# root and users in the wheel group.
|
||
assertion = !cfg.mutableUsers ->
|
||
any id (mapAttrsToList (name: cfg:
|
||
(name == "root"
|
||
|| cfg.group == "wheel"
|
||
|| elem "wheel" cfg.extraGroups)
|
||
&&
|
||
((cfg.hashedPassword != null && cfg.hashedPassword != "!")
|
||
|| cfg.password != null
|
||
|| cfg.passwordFile != null
|
||
|| cfg.openssh.authorizedKeys.keys != []
|
||
|| cfg.openssh.authorizedKeys.keyFiles != [])
|
||
) cfg.users);
|
||
message = ''
|
||
Neither the root account nor any wheel user has a password or SSH authorized key.
|
||
You must set one to prevent being locked out of your system.'';
|
||
}
|
||
];
|
||
|
||
};
|
||
|
||
}
|