From 223cf9fbc717d90d63006f1d13b8d10afe2b41fa Mon Sep 17 00:00:00 2001
From: M66B <marcel@faircode.eu>
Date: Thu, 11 Feb 2016 07:50:02 +0100
Subject: [PATCH] Better checl VPN/DNS address

---
 .../faircode/netguard/ActivitySettings.java   | 24 +++++++++----------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/app/src/main/java/eu/faircode/netguard/ActivitySettings.java b/app/src/main/java/eu/faircode/netguard/ActivitySettings.java
index 5d761e4a..27678761 100644
--- a/app/src/main/java/eu/faircode/netguard/ActivitySettings.java
+++ b/app/src/main/java/eu/faircode/netguard/ActivitySettings.java
@@ -76,6 +76,7 @@ import java.io.OutputStream;
 import java.net.InetAddress;
 import java.net.MalformedURLException;
 import java.net.URL;
+import java.net.UnknownHostException;
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
 import java.util.Date;
@@ -524,11 +525,8 @@ public class ActivitySettings extends AppCompatActivity implements SharedPrefere
         else if ("vpn4".equals(name)) {
             String vpn4 = prefs.getString("vpn4", null);
             try {
-                if (vpn4 == null || TextUtils.isEmpty(vpn4.trim()))
-                    throw new IllegalArgumentException("vpn4");
-                InetAddress.getByName(vpn4);
+                checkAddress(vpn4);
             } catch (Throwable ex) {
-                Log.w(TAG, ex.toString());
                 prefs.edit().remove("vpn4").apply();
             }
             SinkholeService.reload(null, "changed " + name, this);
@@ -537,11 +535,8 @@ public class ActivitySettings extends AppCompatActivity implements SharedPrefere
         } else if ("vpn6".equals(name)) {
             String vpn6 = prefs.getString("vpn6", null);
             try {
-                if (vpn6 == null || TextUtils.isEmpty(vpn6.trim()))
-                    throw new IllegalArgumentException("vpn6");
-                InetAddress.getByName(vpn6);
+                checkAddress(vpn6);
             } catch (Throwable ex) {
-                Log.w(TAG, ex.toString());
                 prefs.edit().remove("vpn6").apply();
             }
             SinkholeService.reload(null, "changed " + name, this);
@@ -550,11 +545,8 @@ public class ActivitySettings extends AppCompatActivity implements SharedPrefere
         } else if ("dns".equals(name)) {
             String dns = prefs.getString("dns", null);
             try {
-                if (dns == null || TextUtils.isEmpty(dns.trim()))
-                    throw new IllegalArgumentException("dns");
-                InetAddress.getByName(dns);
+                checkAddress(dns);
             } catch (Throwable ex) {
-                Log.w(TAG, ex.toString());
                 prefs.edit().remove("dns").apply();
             }
             SinkholeService.reload(null, "changed " + name, this);
@@ -579,6 +571,14 @@ public class ActivitySettings extends AppCompatActivity implements SharedPrefere
             SinkholeService.reload(null, "changed " + name, this);
     }
 
+    private void checkAddress(String address) throws IllegalArgumentException, UnknownHostException {
+        if (address == null || TextUtils.isEmpty(address.trim()))
+            throw new IllegalArgumentException("Bad address");
+        InetAddress idns = InetAddress.getByName(address);
+        if (idns.isLoopbackAddress() || idns.isAnyLocalAddress())
+            throw new IllegalArgumentException("Bad address");
+    }
+
     @TargetApi(Build.VERSION_CODES.M)
     private void checkPermissions() {
         PreferenceScreen screen = getPreferenceScreen();