AdminKnobs: allow enterprise admins to disable private key export

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

ui/src/main/AndroidManifest.xml

@@ -112,5 +112,8 @@
                 android:name="android.service.quicksettings.ACTIVE_TILE"
                 android:value="false" />
         </service>
+
+        <meta-data android:name="android.content.APP_RESTRICTIONS"
+            android:resource="@xml/app_restrictions" />
     </application>
 </manifest>

ui/src/main/java/com/wireguard/android/activity/SettingsActivity.kt

@@ -17,6 +17,7 @@ import androidx.preference.PreferenceFragmentCompat
 import com.wireguard.android.Application
 import com.wireguard.android.R
 import com.wireguard.android.backend.WgQuickBackend
+import com.wireguard.android.util.AdminKnobs
 import com.wireguard.android.util.ModuleLoader
 import java.util.ArrayList
 import java.util.Arrays
@@ -87,6 +88,10 @@ class SettingsActivity : ThemeChangeAwareActivity() {
                 val remoteApps = preferenceManager.findPreference<Preference>("allow_remote_control_intents")
                 remoteApps?.parent?.removePreference(remoteApps)
             }
+            if (AdminKnobs.disableConfigExport) {
+                val zipExporter = preferenceManager.findPreference<Preference>("zip_exporter")
+                zipExporter?.parent?.removePreference(zipExporter)
+            }
             val wgQuickOnlyPrefs = arrayOf(
                     preferenceManager.findPreference("tools_installer"),
                     preferenceManager.findPreference("restore_on_boot"),

ui/src/main/java/com/wireguard/android/fragment/TunnelEditorFragment.kt

@@ -26,6 +26,7 @@ import com.wireguard.android.databinding.TunnelEditorFragmentBinding
 import com.wireguard.android.fragment.AppListDialogFragment.AppSelectionListener
 import com.wireguard.android.model.ObservableTunnel
 import com.wireguard.android.util.BiometricAuthenticator
+import com.wireguard.android.util.AdminKnobs
 import com.wireguard.android.util.ErrorMessages
 import com.wireguard.android.viewmodel.ConfigProxy
 import com.wireguard.android.widget.EdgeToEdge.setUpRoot
@@ -252,6 +253,7 @@ class TunnelEditorFragment : BaseFragment(), AppSelectionListener {
         val edit = view as? EditText ?: return
         if (edit.inputType == InputType.TYPE_TEXT_FLAG_NO_SUGGESTIONS or InputType.TYPE_TEXT_VARIATION_VISIBLE_PASSWORD) return
         if (!haveShownKeys && edit.text.isNotEmpty()) {
+            if (AdminKnobs.disableConfigExport) return
             showingAuthenticator = true
             BiometricAuthenticator.authenticate(R.string.biometric_prompt_private_key_title, this) {
                 showingAuthenticator = false

ui/src/main/java/com/wireguard/android/preference/ZipExporterPreference.kt

@@ -16,6 +16,7 @@ import com.wireguard.android.R
 import com.wireguard.android.model.ObservableTunnel
 import com.wireguard.android.util.BiometricAuthenticator
 import com.wireguard.android.util.DownloadsFileSaver
+import com.wireguard.android.util.AdminKnobs
 import com.wireguard.android.util.ErrorMessages
 import com.wireguard.android.util.FragmentUtils
 import java9.util.concurrent.CompletableFuture
@@ -82,6 +83,7 @@ class ZipExporterPreference(context: Context, attrs: AttributeSet?) : Preference
     override fun getTitle() = context.getString(R.string.zip_export_title)
 
     override fun onClick() {
+        if (AdminKnobs.disableConfigExport) return
         val prefActivity = FragmentUtils.getPrefActivity(this)
         val fragment = prefActivity.supportFragmentManager.fragments.first()
         BiometricAuthenticator.authenticate(R.string.biometric_prompt_zip_exporter_title, fragment) {

ui/src/main/java/com/wireguard/android/util/AdminKnobs.kt

@@ -0,0 +1,16 @@
+/*
+ * Copyright © 2020 WireGuard LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.wireguard.android.util
+
+import android.content.RestrictionsManager
+import androidx.core.content.getSystemService
+import com.wireguard.android.Application
+
+object AdminKnobs {
+    private val restrictions: RestrictionsManager? = Application.get().getSystemService()
+    val disableConfigExport: Boolean
+        get() = restrictions?.applicationRestrictions?.getBoolean("disable_config_export", false) ?: false
+}

ui/src/main/res/values/strings.xml

@@ -101,6 +101,8 @@
     <string name="dark_theme_summary_on">Currently using dark (night) theme</string>
     <string name="dark_theme_title">Use dark theme</string>
     <string name="delete">Delete</string>
+    <string name="disable_config_export_title">Disable config exporting</string>
+    <string name="disable_config_export_description">Disabling config exporting makes private keys less accessible</string>
     <string name="dns_servers">DNS servers</string>
     <string name="edit">Edit</string>
     <string name="endpoint">Endpoint</string>

ui/src/main/res/xml/app_restrictions.xml

@@ -0,0 +1,13 @@
+<!--
+  ~ Copyright © 2020 WireGuard LLC. All Rights Reserved.
+  ~ SPDX-License-Identifier: Apache-2.0
+  -->
+
+<restrictions xmlns:android="http://schemas.android.com/apk/res/android">
+    <restriction
+        android:defaultValue="false"
+        android:description="@string/disable_config_export_description"
+        android:key="disable_config_export"
+        android:restrictionType="bool"
+        android:title="@string/disable_config_export_title" />
+</restrictions>