89 lines
4.2 KiB
XML
89 lines
4.2 KiB
XML
<chapter xmlns="http://docbook.org/ns/docbook"
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xmlns:xlink="http://www.w3.org/1999/xlink"
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xmlns:xi="http://www.w3.org/2001/XInclude"
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version="5.0"
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xml:id="sec-user-management">
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<title>User Management</title>
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<para>
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NixOS supports both declarative and imperative styles of user management. In
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the declarative style, users are specified in
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<filename>configuration.nix</filename>. For instance, the following states
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that a user account named <literal>alice</literal> shall exist:
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<programlisting>
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<xref linkend="opt-users.users"/>.alice = {
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<link linkend="opt-users.users._name__.isNormalUser">isNormalUser</link> = true;
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<link linkend="opt-users.users._name__.home">home</link> = "/home/alice";
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<link linkend="opt-users.users._name__.description">description</link> = "Alice Foobar";
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<link linkend="opt-users.users._name__.extraGroups">extraGroups</link> = [ "wheel" "networkmanager" ];
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<link linkend="opt-users.users._name__.openssh.authorizedKeys.keys">openssh.authorizedKeys.keys</link> = [ "ssh-dss AAAAB3Nza... alice@foobar" ];
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};
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</programlisting>
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Note that <literal>alice</literal> is a member of the
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<literal>wheel</literal> and <literal>networkmanager</literal> groups, which
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allows her to use <command>sudo</command> to execute commands as
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<literal>root</literal> and to configure the network, respectively. Also note
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the SSH public key that allows remote logins with the corresponding private
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key. Users created in this way do not have a password by default, so they
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cannot log in via mechanisms that require a password. However, you can use
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the <command>passwd</command> program to set a password, which is retained
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across invocations of <command>nixos-rebuild</command>.
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</para>
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<para>
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If you set <xref linkend="opt-users.mutableUsers"/> to false, then the
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contents of <literal>/etc/passwd</literal> and <literal>/etc/group</literal>
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will be congruent to your NixOS configuration. For instance, if you remove a
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user from <xref linkend="opt-users.users"/> and run nixos-rebuild, the user
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account will cease to exist. Also, imperative commands for managing users and
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groups, such as useradd, are no longer available. Passwords may still be
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assigned by setting the user's
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<link linkend="opt-users.users._name__.hashedPassword">hashedPassword</link>
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option. A hashed password can be generated using <command>mkpasswd -m
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sha-512</command> after installing the <literal>mkpasswd</literal> package.
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</para>
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<para>
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A user ID (uid) is assigned automatically. You can also specify a uid
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manually by adding
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<programlisting>
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uid = 1000;
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</programlisting>
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to the user specification.
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</para>
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<para>
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Groups can be specified similarly. The following states that a group named
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<literal>students</literal> shall exist:
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<programlisting>
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<xref linkend="opt-users.groups"/>.students.gid = 1000;
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</programlisting>
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As with users, the group ID (gid) is optional and will be assigned
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automatically if it’s missing.
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</para>
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<para>
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In the imperative style, users and groups are managed by commands such as
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<command>useradd</command>, <command>groupmod</command> and so on. For
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instance, to create a user account named <literal>alice</literal>:
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<screen>
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# useradd -m alice</screen>
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To make all nix tools available to this new user use `su - USER` which opens
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a login shell (==shell that loads the profile) for given user. This will
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create the ~/.nix-defexpr symlink. So run:
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<screen>
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# su - alice -c "true"</screen>
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The flag <option>-m</option> causes the creation of a home directory for the
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new user, which is generally what you want. The user does not have an initial
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password and therefore cannot log in. A password can be set using the
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<command>passwd</command> utility:
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<screen>
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# passwd alice
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Enter new UNIX password: ***
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Retype new UNIX password: ***
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</screen>
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A user can be deleted using <command>userdel</command>:
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<screen>
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# userdel -r alice</screen>
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The flag <option>-r</option> deletes the user’s home directory. Accounts
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can be modified using <command>usermod</command>. Unix groups can be managed
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using <command>groupadd</command>, <command>groupmod</command> and
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<command>groupdel</command>.
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</para>
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</chapter>
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