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Block non-VPN incoming traffic in lockdown mode #235

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Block non-VPN incoming traffic in lockdown mode #235

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42 changes: 40 additions & 2 deletions app/src/main/java/de/blinkt/openvpn/core/OpenVPNService.java
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Original file line number Diff line number Diff line change
Expand Up @@ -93,6 +93,7 @@ public class OpenVPNService extends VpnService implements StateListener, Callbac
private Shapeshifter shapeshifter;
private ObfsVpnClient obfsVpnClient;
private FirewallManager firewallManager;
private boolean mIsLockdownEnabled = false;

private final IBinder mBinder = new IOpenVPNServiceInternal.Stub() {

Expand Down Expand Up @@ -576,10 +577,38 @@ private String getTunConfigString() {
return cfg;
}

public void determineLockdownState() {
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This was added to work around the fact that isLockdownEnabled() always returns false unless the VPN is established.

Builder builder = new Builder();

try {
builder.addAddress(mLocalIP.mIp, mLocalIP.len);
} catch (IllegalArgumentException iae) {
return;
}

ParcelFileDescriptor tun = null;
try {
tun = builder.establish();
mIsLockdownEnabled = isLockdownEnabledCompat();
} catch (Exception e) {
VpnStatus.logError(getString(R.string.error) + e.getLocalizedMessage());
} finally {
if (tun != null) {
try {
tun.close();
} catch (Exception e) {
VpnStatus.logError(getString(R.string.error) + e.getLocalizedMessage());
}
}
}
}

public ParcelFileDescriptor openTun() {

//Debug.startMethodTracing(getExternalFilesDir(null).toString() + "/opentun.trace", 40* 1024 * 1024);

determineLockdownState();

if (mProfile == null) {
VpnStatus.logError("Refusing to open tun device without profile.");
return null;
Expand Down Expand Up @@ -641,6 +670,15 @@ public ParcelFileDescriptor openTun() {
builder.setMtu(mMtu);
}

// Don't exclude local addresses at all in lockdown mode.
// Otherwise, incoming traffic can still bypass lockdown (AOSP quirk/bug).
if (mIsLockdownEnabled) {
mRoutes.clear();
mRoutesv6.clear();
addRoute(new CIDRIP("0.0.0.0", 0), true);
addRoutev6("::/0", true);
}

Collection<IpAddress> positiveIPv4Routes = mRoutes.getPositiveIPList();
Collection<IpAddress> positiveIPv6Routes = mRoutesv6.getPositiveIPList();

Expand Down Expand Up @@ -715,7 +753,7 @@ public ParcelFileDescriptor openTun() {
ipv6info = mLocalIPv6;
}

if ((!mRoutes.getNetworks(false).isEmpty() || !mRoutesv6.getNetworks(false).isEmpty()) && isLockdownEnabledCompat())
if ((!mRoutes.getNetworks(false).isEmpty() || !mRoutesv6.getNetworks(false).isEmpty()) && mIsLockdownEnabled)
{
VpnStatus.logInfo("VPN lockdown enabled (do not allow apps to bypass VPN) enabled. Route exclusion will not allow apps to bypass VPN (e.g. bypass VPN for local networks)");
}
Expand Down Expand Up @@ -1168,4 +1206,4 @@ public void trigger_url_open(String info) {
mNotificationManager.notify(notificationId, notification);
*/
}
}
}