implement tethering firewall rules pt.1

5 files changed, 128 insertions, 10 deletions

diff --git a/app/src/main/java/se/leap/bitmaskclient/firewall/ConfigureTetheringTask.java b/app/src/main/java/se/leap/bitmaskclient/firewall/ConfigureTetheringTask.java
new file mode 100644
index 00000000..29e9542d
--- /dev/null
+++ b/app/src/main/java/se/leap/bitmaskclient/firewall/ConfigureTetheringTask.java
@@ -0,0 +1,95 @@
+package se.leap.bitmaskclient.firewall;
+
+import android.os.AsyncTask;
+import android.util.Log;
+
+import java.lang.ref.WeakReference;
+
+import se.leap.bitmaskclient.tethering.TetheringState;
+
+import static se.leap.bitmaskclient.firewall.FirewallManager.BITMASK_FORWARD;
+import static se.leap.bitmaskclient.firewall.FirewallManager.BITMASK_POSTROUTING;
+import static se.leap.bitmaskclient.utils.Cmd.runBlockingCmd;
+
+public class ConfigureTetheringTask extends AsyncTask<TetheringState, Boolean, Boolean> {
+
+    private WeakReference<FirewallCallback> callbackWeakReference;
+
+    ConfigureTetheringTask(FirewallCallback callback) {
+        callbackWeakReference = new WeakReference<>(callback);
+    }
+
+    @Override
+    protected Boolean doInBackground(TetheringState... tetheringStates) {
+        TetheringState tetheringState = tetheringStates[0];
+        StringBuilder log = new StringBuilder();
+
+        String[] bitmaskChain = new String[]{
+                "su",
+                "id",
+                "iptables --list " + BITMASK_FORWARD + " && iptables --list " + BITMASK_POSTROUTING };
+
+        try {
+            boolean hasBitmaskChain = runBlockingCmd(bitmaskChain, log) == 0;
+            boolean allowSu = log.toString().contains("uid=0");
+            callbackWeakReference.get().onSuRequested(allowSu);
+            if (!allowSu) {
+                return false;
+            }
+
+            boolean success;
+            log = new StringBuilder();
+            if (hasAnyTetheringEnabled(tetheringState)) {
+                if (!hasBitmaskChain) {
+                    String[] createChains = new String[]{
+                            "su",
+                            "iptables -t filter --new-chain " + BITMASK_FORWARD,
+                            "iptables -t nat --new-chain " + BITMASK_POSTROUTING,
+                            "iptables -t filter --insert FORWARD --jump " + BITMASK_FORWARD,
+                            "iptables -t nat --insert POSTROUTING --jump " + BITMASK_POSTROUTING,
+                    };
+                    success = runBlockingCmd(createChains, log) == 0;
+                    Log.d(FirewallManager.TAG, "added " + BITMASK_FORWARD + " and " + BITMASK_POSTROUTING+" to iptables: " + success);
+                    Log.d(FirewallManager.TAG, log.toString());
+                }
+
+                String[] addRules = new String[] {
+                        "su",
+                        "iptables -t filter --flush " + BITMASK_FORWARD,
+                        "iptables -t nat --flush " + BITMASK_POSTROUTING,
+                        "iptables -t filter --append " + BITMASK_FORWARD + " --jump ACCEPT",
+                        "iptables -t nat --append " + BITMASK_POSTROUTING + " --jump MASQUERADE" };
+                return runBlockingCmd(addRules, log) == 0;
+            } else {
+                if (!hasBitmaskChain) return true;
+                String[] removeChains = new String[] {
+                        "su",
+                        "iptables -t filter --delete FORWARD --jump " + BITMASK_FORWARD,
+                        "iptables -t nat --delete POSTROUTING --jump " + BITMASK_POSTROUTING,
+                        "iptables -t filter --flush " + BITMASK_FORWARD,
+                        "iptables -t nat --flush " + BITMASK_POSTROUTING,
+                        "iptables -t filter --delete-chain " + BITMASK_FORWARD,
+                        "iptables -t nat --delete-chain " + BITMASK_POSTROUTING
+                };
+                return runBlockingCmd(removeChains, log) == 0;
+            }
+        } catch (Exception e) {
+            e.printStackTrace();
+            Log.e(FirewallManager.TAG, log.toString());
+        }
+        return false;
+    }
+
+    @Override
+    protected void onPostExecute(Boolean result) {
+        super.onPostExecute(result);
+        FirewallCallback callback = callbackWeakReference.get();
+        if (callback != null) {
+            callback.onTetheringConfigured(result);
+        }
+    }
+
+    private boolean hasAnyTetheringEnabled(TetheringState state) {
+        return state.isBluetoothTetheringEnabled || state.isUsbTetheringEnabled || state.isWifiTetheringEnabled;
+    }
+}
diff --git a/app/src/main/java/se/leap/bitmaskclient/firewall/FirewallCallback.java b/app/src/main/java/se/leap/bitmaskclient/firewall/FirewallCallback.java
index f6ccd227..76618b8c 100644
--- a/app/src/main/java/se/leap/bitmaskclient/firewall/FirewallCallback.java
+++ b/app/src/main/java/se/leap/bitmaskclient/firewall/FirewallCallback.java
@@ -3,5 +3,6 @@ package se.leap.bitmaskclient.firewall;
 interface FirewallCallback {
     void onFirewallStarted(boolean success);
     void onFirewallStopped(boolean success);
+    void onTetheringConfigured(boolean success);
     void onSuRequested(boolean success);
 }
diff --git a/app/src/main/java/se/leap/bitmaskclient/firewall/FirewallManager.java b/app/src/main/java/se/leap/bitmaskclient/firewall/FirewallManager.java
index a3be46e6..a7cb2253 100644
--- a/app/src/main/java/se/leap/bitmaskclient/firewall/FirewallManager.java
+++ b/app/src/main/java/se/leap/bitmaskclient/firewall/FirewallManager.java
@@ -24,6 +24,8 @@ import se.leap.bitmaskclient.utils.PreferenceHelper;
 
 public class FirewallManager implements FirewallCallback {
     public static String BITMASK_CHAIN = "bitmask_fw";
+    public static String BITMASK_FORWARD = "bitmask_forward";
+    public static String BITMASK_POSTROUTING = "bitmask_postrouting";
     static final String TAG = FirewallManager.class.getSimpleName();
 
     private Context context;
@@ -52,6 +54,15 @@ public class FirewallManager implements FirewallCallback {
     }
 
     @Override
+    public void onTetheringConfigured(boolean success) {
+        if (success) {
+            VpnStatus.logInfo("[FIREWALL] Rules for tethering configured");
+        } else {
+            VpnStatus.logError("[FIREWALL] Could not establish rules for tethering ");
+        }
+    }
+
+    @Override
     public void onSuRequested(boolean success) {
         PreferenceHelper.setSuPermission(context, success);
         if (!success) {
diff --git a/app/src/main/java/se/leap/bitmaskclient/tethering/TetheringObservable.java b/app/src/main/java/se/leap/bitmaskclient/tethering/TetheringObservable.java
index 9ea9160f..fc06ee12 100644
--- a/app/src/main/java/se/leap/bitmaskclient/tethering/TetheringObservable.java
+++ b/app/src/main/java/se/leap/bitmaskclient/tethering/TetheringObservable.java
@@ -21,11 +21,11 @@ import java.util.Observable;
 public class TetheringObservable extends Observable {
     private static TetheringObservable instance;
 
-    private boolean isWifiTetheringEnabled;
-    private boolean isUsbTetheringEnabled;
-    private boolean isBluetoothTetheringEnabled;
+    private TetheringState tetheringState;
 
-    private TetheringObservable() { }
+    private TetheringObservable() {
+        tetheringState = new TetheringState();
+    }
 
     public static TetheringObservable getInstance() {
         if (instance == null) {
@@ -35,32 +35,36 @@ public class TetheringObservable extends Observable {
     }
 
     static void setWifiTethering(boolean enabled) {
-        getInstance().isWifiTetheringEnabled = enabled;
+        getInstance().tetheringState.isWifiTetheringEnabled = enabled;
         getInstance().setChanged();
         getInstance().notifyObservers();
     }
 
     static void setUsbTethering(boolean enabled) {
-        getInstance().isUsbTetheringEnabled = enabled;
+        getInstance().tetheringState.isUsbTetheringEnabled = enabled;
         getInstance().setChanged();
         getInstance().notifyObservers();
     }
 
     static void setBluetoothTethering(boolean enabled) {
-        getInstance().isBluetoothTetheringEnabled = enabled;
+        getInstance().tetheringState.isBluetoothTetheringEnabled = enabled;
         getInstance().setChanged();
         getInstance().notifyObservers();
     }
 
     public boolean isBluetoothTetheringEnabled() {
-        return isBluetoothTetheringEnabled;
+        return tetheringState.isBluetoothTetheringEnabled;
     }
 
     public boolean isUsbTetheringEnabled() {
-        return isUsbTetheringEnabled;
+        return tetheringState.isUsbTetheringEnabled;
     }
 
     public boolean isWifiTetheringEnabled() {
-        return isWifiTetheringEnabled;
+        return tetheringState.isWifiTetheringEnabled;
+    }
+
+    public TetheringState getTetheringState() {
+        return tetheringState;
     }
 }
diff --git a/app/src/main/java/se/leap/bitmaskclient/tethering/TetheringState.java b/app/src/main/java/se/leap/bitmaskclient/tethering/TetheringState.java
new file mode 100644
index 00000000..50fead91
--- /dev/null
+++ b/app/src/main/java/se/leap/bitmaskclient/tethering/TetheringState.java
@@ -0,0 +1,7 @@
+package se.leap.bitmaskclient.tethering;
+
+public class TetheringState {
+    public boolean isWifiTetheringEnabled;
+    public boolean isUsbTetheringEnabled;
+    public boolean isBluetoothTetheringEnabled;
+}