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package se.leap.bitmaskclient.utils;
/**
* Copyright (c) 2019 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 <http://www.gnu.org/licenses/>.
*/
import android.content.Context;
import android.os.AsyncTask;
import android.util.Log;
import java.lang.ref.WeakReference;
import de.blinkt.openvpn.core.VpnStatus;
import static se.leap.bitmaskclient.utils.Cmd.runBlockingCmd;
interface FirewallCallback {
void onFirewallStarted(boolean success);
void onFirewallStopped(boolean success);
void onSuRequested(boolean success);
}
public class FirewallHelper implements FirewallCallback {
private static String BITMASK_CHAIN = "bitmask_fw";
private static final String TAG = FirewallHelper.class.getSimpleName();
private Context context;
public FirewallHelper(Context context) {
this.context = context;
}
@Override
public void onFirewallStarted(boolean success) {
if (success) {
VpnStatus.logInfo("[FIREWALL] Custom rules established");
} else {
VpnStatus.logError("[FIREWALL] Could not establish custom rules.");
}
}
@Override
public void onFirewallStopped(boolean success) {
if (success) {
VpnStatus.logInfo("[FIREWALL] Custom rules deleted");
} else {
VpnStatus.logError("[FIREWALL] Could not delete custom rules");
}
}
@Override
public void onSuRequested(boolean success) {
PreferenceHelper.setSuPermission(context, success);
if (!success) {
VpnStatus.logError("[FIREWALL] Root permission needed to execute custom firewall rules.");
}
}
private static class StartFirewallTask extends AsyncTask<Void, Boolean, Boolean> {
WeakReference<FirewallCallback> callbackWeakReference;
StartFirewallTask(FirewallCallback callback) {
callbackWeakReference = new WeakReference<>(callback);
}
@Override
protected Boolean doInBackground(Void... voids) {
StringBuilder log = new StringBuilder();
String[] bitmaskChain = new String[]{
"su",
"id",
"ip6tables --list " + BITMASK_CHAIN };
try {
boolean hasBitmaskChain = runBlockingCmd(bitmaskChain, log) == 0;
boolean allowSu = log.toString().contains("uid=0");
try {
callbackWeakReference.get().onSuRequested(allowSu);
Thread.sleep(1000);
} catch (Exception e) {
//ignore
}
boolean success;
log = new StringBuilder();
if (!hasBitmaskChain) {
String[] createChainAndRules = new String[]{
"su",
"ip6tables --new-chain " + BITMASK_CHAIN,
"ip6tables --insert OUTPUT --jump " + BITMASK_CHAIN,
"ip6tables --append " + BITMASK_CHAIN + " -p tcp --jump REJECT",
"ip6tables --append " + BITMASK_CHAIN + " -p udp --jump REJECT"
};
success = runBlockingCmd(createChainAndRules, log) == 0;
Log.d(TAG, "added " + BITMASK_CHAIN + " to ip6tables: " + success);
Log.d(TAG, log.toString());
return success;
} else {
String[] addRules = new String[] {
"su",
"ip6tables --append " + BITMASK_CHAIN + " -p tcp --jump REJECT",
"ip6tables --append " + BITMASK_CHAIN + " -p udp --jump REJECT" };
return runBlockingCmd(addRules, log) == 0;
}
} catch (Exception e) {
e.printStackTrace();
Log.e(TAG, log.toString());
}
return false;
}
@Override
protected void onPostExecute(Boolean result) {
super.onPostExecute(result);
FirewallCallback callback = callbackWeakReference.get();
if (callback != null) {
callback.onFirewallStarted(result);
}
}
}
private static class ShutdownFirewallTask extends AsyncTask<Void, Boolean, Boolean> {
WeakReference<FirewallCallback> callbackWeakReference;
ShutdownFirewallTask(FirewallCallback callback) {
callbackWeakReference = new WeakReference<>(callback);
}
@Override
protected Boolean doInBackground(Void... voids) {
boolean success;
StringBuilder log = new StringBuilder();
String[] deleteChain = new String[]{
"su",
"id",
"ip6tables --delete OUTPUT --jump " + BITMASK_CHAIN,
"ip6tables --flush " + BITMASK_CHAIN,
"ip6tables --delete-chain " + BITMASK_CHAIN
};
try {
success = runBlockingCmd(deleteChain, log) == 0;
} catch (Exception e) {
e.printStackTrace();
Log.e(TAG, log.toString());
return false;
}
try {
boolean allowSu = log.toString().contains("uid=0");
callbackWeakReference.get().onSuRequested(allowSu);
} catch (Exception e) {
//ignore
}
return success;
}
@Override
protected void onPostExecute(Boolean result) {
super.onPostExecute(result);
FirewallCallback callback = callbackWeakReference.get();
if (callback != null) {
callback.onFirewallStopped(result);
}
}
}
public void startFirewall() {
StartFirewallTask task = new StartFirewallTask(this);
task.execute();
}
public void shutdownFirewall() {
ShutdownFirewallTask task = new ShutdownFirewallTask(this);
task.execute();
}
}
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