installer: Don't run as root

There's many reason why it is and is going to
continue to be difficult to do this:

1. All display-managers (excluding slim) default PAM rules
   disallow root auto login.

2. We can't use wayland

3. We have to use system-wide pulseaudio

4. It could break applications in the session.
   This happened to dolphin in plasma5
   in the past.

This is a growing technical debt, let's just use
passwordless sudo.

2 files changed, 27 insertions, 9 deletions

diff --git a/nixos/modules/installer/cd-dvd/installation-cd-graphical-base.nix b/nixos/modules/installer/cd-dvd/installation-cd-graphical-base.nix
index f65239a5bc0..1578e1547bc 100644
--- a/nixos/modules/installer/cd-dvd/installation-cd-graphical-base.nix
+++ b/nixos/modules/installer/cd-dvd/installation-cd-graphical-base.nix
@@ -8,16 +8,30 @@ with lib;
 {
   imports = [ ./installation-cd-base.nix ];
 
+  # Whitelist wheel users to do anything
+  # This is useful for things like pkexec
+  #
+  # WARNING: this is dangerous for systems
+  # outside the installation-cd and shouldn't
+  # be used anywhere else.
+  security.polkit.extraConfig = ''
+    polkit.addRule(function(action, subject) {
+      if (subject.isInGroup("wheel")) {
+        return polkit.Result.YES;
+      }
+    });
+  '';
+
   services.xserver = {
     enable = true;
 
     # Don't start the X server by default.
     autorun = mkForce false;
 
-    # Automatically login as root.
+    # Automatically login as nixos.
     displayManager.slim = {
       enable = true;
-      defaultUser = "root";
+      defaultUser = "nixos";
       autoLogin = true;
     };
 
@@ -33,7 +47,6 @@ with lib;
 
   # Enable sound in graphical iso's.
   hardware.pulseaudio.enable = true;
-  hardware.pulseaudio.systemWide = true; # Needed since we run plasma as root.
 
   environment.systemPackages = [
     # Include gparted for partitioning disks.
diff --git a/nixos/modules/installer/cd-dvd/installation-cd-graphical-kde.nix b/nixos/modules/installer/cd-dvd/installation-cd-graphical-kde.nix
index 1c3c9cb30b4..2536ba73a1d 100644
--- a/nixos/modules/installer/cd-dvd/installation-cd-graphical-kde.nix
+++ b/nixos/modules/installer/cd-dvd/installation-cd-graphical-kde.nix
@@ -1,5 +1,5 @@
 # This module defines a NixOS installation CD that contains X11 and
-# Plasma5.
+# Plasma 5.
 
 { config, lib, pkgs, ... }:
 
@@ -30,15 +30,20 @@ with lib;
       Version=1.0
       Type=Application
       Name=NixOS Manual
-      Exec=firefox ${config.system.build.manual.manualHTMLIndex}
+      Exec=firefox ${config.system.build.manual.manual}/share/doc/nixos/index.html
       Icon=text-html
     '';
 
+    homeDir = "/home/nixos/";
+    desktopDir = homeDir + "Desktop/";
+
   in ''
-    mkdir -p /root/Desktop
-    ln -sfT ${manualDesktopFile} /root/Desktop/nixos-manual.desktop
-    ln -sfT ${pkgs.konsole}/share/applications/org.kde.konsole.desktop /root/Desktop/org.kde.konsole.desktop
-    ln -sfT ${pkgs.gparted}/share/applications/gparted.desktop /root/Desktop/gparted.desktop
+    mkdir -p ${desktopDir}
+    chown nixos ${homeDir} ${desktopDir}
+
+    ln -sfT ${manualDesktopFile} ${desktopDir + "nixos-manual.desktop"}
+    ln -sfT ${pkgs.gparted}/share/applications/gparted.desktop ${desktopDir + "gparted.desktop"}
+    ln -sfT ${pkgs.konsole}/share/applications/org.kde.konsole.desktop ${desktopDir + "org.kde.konsole.desktop"}
   '';
 
 }