VPN: convert prepare() into a form which helps solve race conditions. (100155a3) · Commits · e / os / android_frameworks_base

core/java/android/net/IConnectivityManager.aidl

+1 −1

Original line number	Diff line number	Diff line
		@@ -101,7 +101,7 @@ interface IConnectivityManager

		void protectVpn(in ParcelFileDescriptor socket);

		String prepareVpn(String packageName);
		boolean prepareVpn(String oldPackage, String newPackage);

		ParcelFileDescriptor establishVpn(in VpnConfig config);

packages/VpnDialogs/src/com/android/vpndialogs/ConfirmDialog.java

+5 −6

Original line number	Diff line number	Diff line
		@@ -36,7 +36,7 @@ public class ConfirmDialog extends Activity implements CompoundButton.OnCheckedC
		DialogInterface.OnClickListener, DialogInterface.OnDismissListener {
		private static final String TAG = "VpnConfirm";

		private String mPackageName;
		private String mPackage;

		private IConnectivityManager mService;

		@@ -47,19 +47,19 @@ public class ConfirmDialog extends Activity implements CompoundButton.OnCheckedC
		protected void onResume() {
		super.onResume();
		try {
		mPackageName = getCallingPackage();
		mPackage = getCallingPackage();

		mService = IConnectivityManager.Stub.asInterface(
		ServiceManager.getService(Context.CONNECTIVITY_SERVICE));

		if (mPackageName.equals(mService.prepareVpn(null))) {
		if (mService.prepareVpn(mPackage, null)) {
		setResult(RESULT_OK);
		finish();
		return;
		}

		PackageManager pm = getPackageManager();
		ApplicationInfo app = pm.getApplicationInfo(mPackageName, 0);
		ApplicationInfo app = pm.getApplicationInfo(mPackage, 0);

		View view = View.inflate(this, R.layout.confirm, null);
		((ImageView) view.findViewById(R.id.icon)).setImageDrawable(app.loadIcon(pm));
		@@ -103,8 +103,7 @@ public class ConfirmDialog extends Activity implements CompoundButton.OnCheckedC
		@Override
		public void onClick(DialogInterface dialog, int which) {
		try {
		if (which == AlertDialog.BUTTON_POSITIVE &&
		mPackageName.equals(mService.prepareVpn(mPackageName))) {
		if (which == AlertDialog.BUTTON_POSITIVE && mService.prepareVpn(null, mPackage)) {
		setResult(RESULT_OK);
		}
		} catch (Exception e) {

packages/VpnDialogs/src/com/android/vpndialogs/ManageDialog.java

+1 −1

Original line number	Diff line number	Diff line
		@@ -125,7 +125,7 @@ public class ManageDialog extends Activity implements Handler.Callback,
		if (which == AlertDialog.BUTTON_POSITIVE) {
		mConfig.configureIntent.send();
		} else if (which == AlertDialog.BUTTON_NEUTRAL) {
		mService.prepareVpn(VpnConfig.LEGACY_VPN);
		mService.prepareVpn(mConfig.packagz, VpnConfig.LEGACY_VPN);
		}
		} catch (Exception e) {
		Log.e(TAG, "onClick", e);

services/java/com/android/server/ConnectivityService.java

+2 −2

Original line number	Diff line number	Diff line
		@@ -2485,8 +2485,8 @@ public class ConnectivityService extends IConnectivityManager.Stub {
		* @hide
		*/
		@Override
		public String prepareVpn(String packageName) {
		return mVpn.prepare(packageName);
		public boolean prepareVpn(String oldPackage, String newPackage) {
		return mVpn.prepare(oldPackage, newPackage);
		}

		/**

services/java/com/android/server/connectivity/Vpn.java

+37 −30

Original line number	Diff line number	Diff line
		@@ -85,31 +85,45 @@ public class Vpn extends INetworkManagementEventObserver.Stub {
		}

		/**
		* Prepare for a VPN application. If the new application is valid,
		* the previous prepared application is revoked. Since legacy VPN
		* is not a real application, it uses {@link VpnConfig#LEGACY_VPN}
		* as its package name. Note that this method does not check if
		* the applications are the same.
		* Prepare for a VPN application. This method is designed to solve
		* race conditions. It first compares the current prepared package
		* with {@code oldPackage}. If they are the same, the prepared
		* package is revoked and replaced with {@code newPackage}. If
		* {@code oldPackage} is {@code null}, the comparison is omitted.
		* If {@code newPackage} is the same package or {@code null}, the
		* revocation is omitted. This method returns {@code true} if the
		* operation is succeeded.
		*
		* @param packageName The package name of the VPN application.
		* @return The package name of the current prepared application.
		* Legacy VPN is handled specially since it is not a real package.
		* It uses {@link VpnConfig#LEGACY_VPN} as its package name, and
		* it can be revoked by itself.
		*
		* @param oldPackage The package name of the old VPN application.
		* @param newPackage The package name of the new VPN application.
		* @return true if the operation is succeeded.
		*/
		public synchronized String prepare(String packageName) {
		// Return the current prepared application if the new one is null.
		if (packageName == null) {
		return mPackageName;
		public synchronized boolean prepare(String oldPackage, String newPackage) {
		// Return false if the package does not match.
		if (oldPackage != null && !oldPackage.equals(mPackageName)) {
		return false;
		}

		// Return true if we do not need to revoke.
		if (newPackage == null \|\|
		(newPackage.equals(mPackageName) && !newPackage.equals(VpnConfig.LEGACY_VPN))) {
		return true;
		}

		// Only system user can call this method.
		// Only system user can revoke a package.
		if (Binder.getCallingUid() != Process.SYSTEM_UID) {
		throw new SecurityException("Unauthorized Caller");
		}

		// Check the permission of the given package.
		PackageManager pm = mContext.getPackageManager();
		if (!packageName.equals(VpnConfig.LEGACY_VPN) &&
		pm.checkPermission(VPN, packageName) != PackageManager.PERMISSION_GRANTED) {
		throw new SecurityException(packageName + " does not have " + VPN);
		if (!newPackage.equals(VpnConfig.LEGACY_VPN) &&
		pm.checkPermission(VPN, newPackage) != PackageManager.PERMISSION_GRANTED) {
		throw new SecurityException(newPackage + " does not have " + VPN);
		}

		// Reset the interface and hide the notification.
		@@ -131,15 +145,15 @@ public class Vpn extends INetworkManagementEventObserver.Stub {
		mLegacyVpnRunner = null;
		}

		Log.i(TAG, "Switched from " + mPackageName + " to " + packageName);
		mPackageName = packageName;
		return mPackageName;
		Log.i(TAG, "Switched from " + mPackageName + " to " + newPackage);
		mPackageName = newPackage;
		return true;
		}

		/**
		* Establish a VPN network and return the file descriptor of the VPN
		* interface. This methods returns {@code null} if the application is
		* not prepared or revoked.
		* revoked or not prepared.
		*
		* @param config The parameters to configure the network.
		* @return The file descriptor of the VPN interface.
		@@ -279,20 +293,13 @@ public class Vpn extends INetworkManagementEventObserver.Stub {
		* @param mtpd The arguments to be passed to mtpd.
		*/
		public synchronized void doLegacyVpn(VpnConfig config, String[] racoon, String[] mtpd) {
		// There is nothing to stop if another VPN application is prepared.
		if (config == null && !mPackageName.equals(VpnConfig.LEGACY_VPN)) {
		return;
		}

		// Reset everything. This also checks the caller.
		prepare(VpnConfig.LEGACY_VPN);
		// Prepare for the new request. This also checks the caller.
		prepare(null, VpnConfig.LEGACY_VPN);

		// Start a new runner and we are done!
		if (config != null) {
		mLegacyVpnRunner = new LegacyVpnRunner(config, racoon, mtpd);
		mLegacyVpnRunner.start();
		}
		}

		/**
		* Bringing up a VPN connection takes time, and that is all this thread