From 1b1bcd7b7370866bc00ce3361be8d5167bf3e28d Mon Sep 17 00:00:00 2001
From: Robin Lee <rgl@google.com>
Date: Fri, 12 Feb 2016 18:11:30 +0000
Subject: [PATCH] Disallow prepare()-ing over an always on VPN app

Bug: 27042309
Change-Id: I6aa069a91f20b645f4d23e796ea03b0355155c41
---
 .../core/java/com/android/server/connectivity/Vpn.java     | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/services/core/java/com/android/server/connectivity/Vpn.java b/services/core/java/com/android/server/connectivity/Vpn.java
index f231f922a0e60..e87a2b5df2a3d 100644
--- a/services/core/java/com/android/server/connectivity/Vpn.java
+++ b/services/core/java/com/android/server/connectivity/Vpn.java
@@ -264,7 +264,12 @@ public class Vpn {
             return true;
         }
 
-        // Check if the caller is authorized.
+        // Stop an existing always-on VPN from being dethroned by other apps.
+        if (getAlwaysOnPackage() != null) {
+            return false;
+        }
+
+        // Check that the caller is authorized.
         enforceControlPermission();
 
         prepareInternal(newPackage);