659 lines
22 KiB
Nix
659 lines
22 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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# Check whether a password hash will allow login.
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allowsLogin = hash:
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hash == "" # login without password
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|| !(lib.elem hash
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[ null # password login disabled
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"!" # password login disabled
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"!!" # a variant of "!"
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"*" # password unset
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]);
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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 a hashed password run <literal>mkpasswd -m sha-512</literal>.
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If set to an empty string (<literal>""</literal>), this user will
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be able to log in without being asked for a password (but not via remote
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services such as SSH, or indirectly via <command>su</command> or
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<command>sudo</command>). This should only be used for e.g. bootable
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live systems. Note: this is different from setting an empty password,
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which ca be achieved using <option>users.users.<name?>.password</option>.
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If set to <literal>null</literal> (default) this user will not
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be able to log in using a password (i.e. via <command>login</command>
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command).
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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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pamMount = mkOption {
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type = with types; attrsOf str;
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default = {};
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description = ''
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Attributes for user's entry in
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<filename>pam_mount.conf.xml</filename>.
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Useful attributes might include <code>path</code>,
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<code>options</code>, <code>fstype</code>, and <code>server</code>.
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See <link
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xlink:href="http://pam-mount.sourceforge.net/pam_mount.conf.5.html" />
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for more information.
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'';
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};
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shell = mkOption {
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type = types.nullOr (types.either types.shellPackage types.path);
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default = pkgs.shadow;
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defaultText = "pkgs.shadow";
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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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Whether to create the home directory and ensure ownership as well as
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permissions to 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; 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; 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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${passwordDescription}
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'';
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};
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passwordFile = mkOption {
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type = with types; nullOr str;
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default = null;
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description = ''
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The full path to a file that contains the user's password. The password
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file is read on each system activation. The file should contain
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exactly one line, which should be the password in an encrypted form
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that is suitable for the <literal>chpasswd -e</literal> command.
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${passwordDescription}
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'';
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};
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initialHashedPassword = mkOption {
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type = with types; 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; 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 available 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/${config.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, ... }: {
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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 str;
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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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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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isNormalUser subUidRanges subGidRanges
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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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imports = [
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(mkAliasOptionModule [ "users" "extraUsers" ] [ "users" "users" ])
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(mkAliasOptionModule [ "users" "extraGroups" ] [ "users" "groups" ])
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(mkChangedOptionModule
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[ "security" "initialRootPassword" ]
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[ "users" "users" "root" "initialHashedPassword" ]
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(cfg: if cfg.security.initialRootPassword == "!"
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then null
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else cfg.security.initialRootPassword))
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];
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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; attrsOf (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; attrsOf (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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};
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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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};
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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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kvm.gid = ids.gids.kvm;
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||
render.gid = ids.gids.render;
|
||
shadow.gid = ids.gids.shadow;
|
||
};
|
||
|
||
system.activationScripts.users = stringAfter [ "stdio" ]
|
||
''
|
||
install -m 0700 -d /root
|
||
install -m 0755 -d /home
|
||
|
||
${pkgs.perl}/bin/perl -w \
|
||
-I${pkgs.perlPackages.FileSlurp}/${pkgs.perl.libPrefix} \
|
||
-I${pkgs.perlPackages.JSON}/${pkgs.perl.libPrefix} \
|
||
${./update-users-groups.pl} ${spec}
|
||
'';
|
||
|
||
# for backwards compatibility
|
||
system.activationScripts.groups = stringAfter [ "users" ] "";
|
||
|
||
# Install all the user shells
|
||
environment.systemPackages = systemShells;
|
||
|
||
environment.etc = (mapAttrs' (name: { packages, ... }: {
|
||
name = "profiles/per-user/${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 = [
|
||
"$HOME/.nix-profile"
|
||
"/etc/profiles/per-user/$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)
|
||
&&
|
||
(allowsLogin cfg.hashedPassword
|
||
|| cfg.password != null
|
||
|| cfg.passwordFile != null
|
||
|| cfg.openssh.authorizedKeys.keys != []
|
||
|| cfg.openssh.authorizedKeys.keyFiles != [])
|
||
) cfg.users) ++ [
|
||
config.security.googleOsLogin.enable
|
||
]);
|
||
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.'';
|
||
}
|
||
] ++ flip mapAttrsToList cfg.users (name: user:
|
||
{
|
||
assertion = (user.hashedPassword != null)
|
||
-> (builtins.match ".*:.*" user.hashedPassword == null);
|
||
message = ''
|
||
The password hash of user "${name}" contains a ":" character.
|
||
This is invalid and would break the login system because the fields
|
||
of /etc/shadow (file where hashes are stored) are colon-separated.
|
||
Please check the value of option `users.users."${name}".hashedPassword`.'';
|
||
}
|
||
);
|
||
|
||
warnings =
|
||
builtins.filter (x: x != null) (
|
||
flip mapAttrsToList cfg.users (name: user:
|
||
# This regex matches a subset of the Modular Crypto Format (MCF)[1]
|
||
# informal standard. Since this depends largely on the OS or the
|
||
# specific implementation of crypt(3) we only support the (sane)
|
||
# schemes implemented by glibc and BSDs. In particular the original
|
||
# DES hash is excluded since, having no structure, it would validate
|
||
# common mistakes like typing the plaintext password.
|
||
#
|
||
# [1]: https://en.wikipedia.org/wiki/Crypt_(C)
|
||
let
|
||
sep = "\\$";
|
||
base64 = "[a-zA-Z0-9./]+";
|
||
id = "[a-z0-9-]+";
|
||
value = "[a-zA-Z0-9/+.-]+";
|
||
options = "${id}(=${value})?(,${id}=${value})*";
|
||
scheme = "${id}(${sep}${options})?";
|
||
content = "${base64}${sep}${base64}";
|
||
mcf = "^${sep}${scheme}${sep}${content}$";
|
||
in
|
||
if (allowsLogin user.hashedPassword
|
||
&& user.hashedPassword != "" # login without password
|
||
&& builtins.match mcf user.hashedPassword == null)
|
||
then ''
|
||
The password hash of user "${name}" may be invalid. You must set a
|
||
valid hash or the user will be locked out of their account. Please
|
||
check the value of option `users.users."${name}".hashedPassword`.''
|
||
else null
|
||
));
|
||
|
||
};
|
||
|
||
}
|