From 09b122daacda168799ad6c3dd100e30eebe47bd4 Mon Sep 17 00:00:00 2001
From: Eran Messeri <eranm@google.com>
Date: Fri, 5 Oct 2018 15:33:53 +0100
Subject: [PATCH] Private DNS: Add user restriction

Add a user restriction to prevent the user from changing the Private DNS
settings.

This would be used together with the new DevicePolicyManager API to set
the Private DNS settings by the Device Policy Client to enforce Private
DNS settings by the IT admin of the user.

Bug: 112982691
Test: atest com.android.cts.devicepolicy.DeviceOwnerTest#testPrivateDnsPolicy
Test: m -j RunSettingsRoboTests ROBOTEST_FILTER=PrivateDnsModeDialogPreferenceTest
Test: Manual, using TestDPC
Change-Id: Ibec3cfcede7e4082db4068cbdd047ada3f6c227e
---
 api/current.txt                                   |  1 +
 core/java/android/os/UserManager.java             | 15 +++++++++++++++
 .../android/server/pm/UserRestrictionsUtils.java  | 10 ++++++++--
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/api/current.txt b/api/current.txt
index 0b6af293f6670..f4b25c1757fb9 100755
--- a/api/current.txt
+++ b/api/current.txt
@@ -33739,6 +33739,7 @@ package android.os {
     field public static final java.lang.String DISALLOW_CONFIG_LOCALE = "no_config_locale";
     field public static final java.lang.String DISALLOW_CONFIG_LOCATION = "no_config_location";
     field public static final java.lang.String DISALLOW_CONFIG_MOBILE_NETWORKS = "no_config_mobile_networks";
+    field public static final java.lang.String DISALLOW_CONFIG_PRIVATE_DNS = "disallow_config_private_dns";
     field public static final java.lang.String DISALLOW_CONFIG_SCREEN_TIMEOUT = "no_config_screen_timeout";
     field public static final java.lang.String DISALLOW_CONFIG_TETHERING = "no_config_tethering";
     field public static final java.lang.String DISALLOW_CONFIG_VPN = "no_config_vpn";
diff --git a/core/java/android/os/UserManager.java b/core/java/android/os/UserManager.java
index 8123744281f44..23599105a1079 100644
--- a/core/java/android/os/UserManager.java
+++ b/core/java/android/os/UserManager.java
@@ -982,6 +982,21 @@ public class UserManager {
      */
     public static final String DISALLOW_PRINTING = "no_printing";
 
+    /**
+     * Specifies whether the user is allowed to modify private DNS settings.
+     *
+     * <p>The default value is <code>false</code>.
+     *
+     * <p>This user restriction can only be applied by the Device Owner.
+     * <p>Key for user restrictions.
+     * <p>Type: Boolean
+     * @see DevicePolicyManager#addUserRestriction(ComponentName, String)
+     * @see DevicePolicyManager#clearUserRestriction(ComponentName, String)
+     * @see #getUserRestrictions()
+     */
+    public static final String DISALLOW_CONFIG_PRIVATE_DNS =
+            "disallow_config_private_dns";
+
     /**
      * Application restriction key that is used to indicate the pending arrival
      * of real restrictions for the app.
diff --git a/services/core/java/com/android/server/pm/UserRestrictionsUtils.java b/services/core/java/com/android/server/pm/UserRestrictionsUtils.java
index 13155027a3875..dd04652a29b30 100644
--- a/services/core/java/com/android/server/pm/UserRestrictionsUtils.java
+++ b/services/core/java/com/android/server/pm/UserRestrictionsUtils.java
@@ -127,7 +127,8 @@ public class UserRestrictionsUtils {
             UserManager.DISALLOW_SHARE_INTO_MANAGED_PROFILE,
             UserManager.DISALLOW_AMBIENT_DISPLAY,
             UserManager.DISALLOW_CONFIG_SCREEN_TIMEOUT,
-            UserManager.DISALLOW_PRINTING
+            UserManager.DISALLOW_PRINTING,
+            UserManager.DISALLOW_CONFIG_PRIVATE_DNS
     });
 
     /**
@@ -163,7 +164,8 @@ public class UserRestrictionsUtils {
      * User restrictions that cannot be set by profile owners. Applied to all users.
      */
     private static final Set<String> DEVICE_OWNER_ONLY_RESTRICTIONS = Sets.newArraySet(
-            UserManager.DISALLOW_USER_SWITCH
+            UserManager.DISALLOW_USER_SWITCH,
+            UserManager.DISALLOW_CONFIG_PRIVATE_DNS
     );
 
     /**
@@ -741,6 +743,10 @@ public class UserRestrictionsUtils {
                 restriction = UserManager.DISALLOW_CONFIG_SCREEN_TIMEOUT;
                 break;
 
+            case android.provider.Settings.Global.PRIVATE_DNS_MODE:
+            case android.provider.Settings.Global.PRIVATE_DNS_SPECIFIER:
+                restriction = UserManager.DISALLOW_CONFIG_PRIVATE_DNS;
+                break;
             default:
                 if (setting.startsWith(Settings.Global.DATA_ROAMING)) {
                     if ("0".equals(value)) {