/**
* Copyright (c) 2020 LEAP Encryption Access Project and contributers
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see .
*/
package se.leap.bitmaskclient.firewall;
import android.os.AsyncTask;
import android.util.Log;
import java.lang.ref.WeakReference;
import java.net.NetworkInterface;
import java.util.ArrayList;
import java.util.Enumeration;
import se.leap.bitmaskclient.tethering.TetheringObservable;
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 SetupTetheringTask extends AsyncTask {
private static final String TAG = SetupTetheringTask.class.getSimpleName();
private WeakReference callbackWeakReference;
SetupTetheringTask(FirewallCallback callback) {
callbackWeakReference = new WeakReference<>(callback);
}
@Override
protected Boolean doInBackground(Void... args) {
TetheringState tetheringState = TetheringObservable.getInstance().getTetheringState();
StringBuilder log = new StringBuilder();
String[] bitmaskChain = new String[]{
"su",
"id",
"iptables -t filter --list " + BITMASK_FORWARD + " && iptables -t nat --list " + BITMASK_POSTROUTING };
try {
boolean hasBitmaskChain = runBlockingCmd(bitmaskChain, log) == 0;
boolean allowSu = log.toString().contains("uid=0");
FirewallCallback callback = callbackWeakReference.get();
if (callback != null) {
callback.onSuRequested(allowSu);
}
if (!allowSu) {
return false;
}
boolean success = true;
log = new StringBuilder();
if (!hasBitmaskChain && tetheringState.hasAnyVpnTetheringAllowed() && tetheringState.hasAnyDeviceTetheringEnabled()) {
createChains(log);
}
if (tetheringState.tetherWifiVpn()) {
log = new StringBuilder();
success = addWifiTetheringRules(tetheringState, log);
logError(success, log);
} else if (!tetheringState.isVpnWifiTetheringAllowed){
success = removeWifiTetheringRules(tetheringState, log);
logError(success, log);
}
log = new StringBuilder();
if (tetheringState.tetherUsbVpn()) {
success = success && addUsbTetheringRules(tetheringState, log);
logError(success, log);
} else if (!tetheringState.isVpnUsbTetheringAllowed) {
success = success && removeUsbTetheringRules(tetheringState, log);
logError(success, log);
}
log = new StringBuilder();
if (tetheringState.tetherBluetoothVpn()) {
success = success && addBluetoothTetheringRules(tetheringState, log);
logError(success, log);
} else if (!tetheringState.isVpnBluetoothTetheringAllowed) {
success = success && removeBluetoothTetheringRules(tetheringState, log);
logError(success, log);
}
return success;
} catch (Exception e) {
e.printStackTrace();
Log.e(FirewallManager.TAG, log.toString());
}
return false;
}
private void logError(boolean success, StringBuilder log) {
if (!success) {
Log.e(TAG, log.toString());
}
}
private void createChains(StringBuilder log) throws Exception {
boolean success;
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());
}
private boolean addWifiTetheringRules(TetheringState state, StringBuilder log) throws Exception {
Log.d(TAG, "add Wifi tethering Rules");
String[] addRules = getAdditionRules(state.wifiAddress, state.wifiInterface);
return runBlockingCmd(addRules, log) == 0;
}
private boolean removeWifiTetheringRules(TetheringState state, StringBuilder log) throws Exception {
Log.d(TAG, "remove Wifi tethering Rules");
String[] removeRules = getDeletionRules(state, state.lastSeenWifiAddress, state.lastSeenWifiInterface);
return runBlockingCmd(removeRules, log) == 0;
}
private boolean addUsbTetheringRules(TetheringState state, StringBuilder log) throws Exception {
Log.d(TAG, "add usb tethering rules");
String[] addRules = getAdditionRules(state.usbAddress, state.usbInterface);
return runBlockingCmd(addRules, log) == 0;
}
private boolean removeUsbTetheringRules(TetheringState state, StringBuilder log) throws Exception {
Log.d(TAG, "remove usb tethering rules");
String[] addRules = getDeletionRules(state, state.lastSeenUsbAddress, state.lastSeenUsbInterface);
return runBlockingCmd(addRules, log) == 0;
}
private boolean addBluetoothTetheringRules(TetheringState state, StringBuilder log) throws Exception {
Log.d(TAG, "add bluetooth tethering rules");
String[] addRules = getAdditionRules(state.bluetoothAddress, state.bluetoothInterface);
return runBlockingCmd(addRules, log) == 0;
}
private boolean removeBluetoothTetheringRules(TetheringState state, StringBuilder log) throws Exception {
Log.d(TAG, "remove bluetooth tethering rules");
String[] addRules = getDeletionRules(state, state.lastSeenBluetoothAddress, state.lastSeenBluetoothInterface);
return runBlockingCmd(addRules, log) == 0;
}
private String[] getAdditionRules(String addressRange, String interfaceName) {
return 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",
"if [[ ! `ip rule show from "+ addressRange+" lookup 61` ]]; " +
"then ip rule add from " + addressRange + " lookup 61; " +
"fi",
"if [[ ! `ip route list table 61 | grep 'default dev " + getTunName() + " scope link'` ]]; " +
"then ip route add default dev " + getTunName() + " scope link table 61; " +
"fi",
"if [[ ! `ip route list table 61 | grep '"+ addressRange +" dev "+ interfaceName +" scope link'` ]]; " +
"then ip route add " + addressRange + " dev " + interfaceName + " scope link table 61; " +
"fi",
"if [[ ! `ip route list table 61 | grep 'broadcast 255.255.255.255 dev " + interfaceName + " scope link'` ]]; " +
"then ip route add broadcast 255.255.255.255 dev " + interfaceName + " scope link table 61; " +
"fi"
};
}
private String[] getDeletionRules(TetheringState state, String addressRange, String interfaceName) {
ArrayList list = new ArrayList<>();
list.add("su");
list.add("ip route delete broadcast 255.255.255.255 dev " + addressRange +" scope link table 61");
list.add("ip route delete " + addressRange + " dev " + interfaceName +" scope link table 61");
if (!state.hasAnyVpnTetheringAllowed() || !state.hasAnyDeviceTetheringEnabled()) {
list.add("ip route delete default dev " + getTunName() + " scope link table 61");
}
list.add("if [[ `ip rule show from " + addressRange + " lookup 61` ]]; " +
"then ip rule del from " + addressRange + " lookup 61; " +
"fi");
return list.toArray(new String[0]);
}
private String getTunName() {
try {
for (Enumeration en = NetworkInterface.getNetworkInterfaces(); en.hasMoreElements(); ) {
NetworkInterface networkInterface = en.nextElement();
if (networkInterface.getName().contains("tun")) {
return networkInterface.getName();
}
}
} catch (Exception e) {
e.printStackTrace();
}
return "";
}
@Override
protected void onPostExecute(Boolean result) {
super.onPostExecute(result);
FirewallCallback callback = callbackWeakReference.get();
if (callback != null) {
callback.onTetheringStarted(result);
}
}
}