Limit the number of MediaSessions per uid (745422a6) · Commits · e / os / android_frameworks_base

media/java/android/media/session/MediaSession.java

+4 −0

Original line number	Original line	Diff line number	Diff line
	@@ -146,6 +146,8 @@ public final class MediaSession {
	* the system but will not be published until {@link #setActive(boolean)		* the system but will not be published until {@link #setActive(boolean)
	* setActive(true)} is called. You must call {@link #release()} when		* setActive(true)} is called. You must call {@link #release()} when
	* finished with the session.		* finished with the session.
			* <p>
			* Note that {@link RuntimeException} will be thrown if an app creates too many sessions.
	*		*
	* @param context The context to use to create the session.		* @param context The context to use to create the session.
	* @param tag A short name for debugging purposes.		* @param tag A short name for debugging purposes.
	@@ -163,6 +165,8 @@ public final class MediaSession {
	* The {@code sessionInfo} can include additional unchanging information about this session.		* The {@code sessionInfo} can include additional unchanging information about this session.
	* For example, it can include the version of the application, or the list of the custom		* For example, it can include the version of the application, or the list of the custom
	* commands that this session supports.		* commands that this session supports.
			* <p>
			* Note that {@link RuntimeException} will be thrown if an app creates too many sessions.
	*		*
	* @param context The context to use to create the session.		* @param context The context to use to create the session.
	* @param tag A short name for debugging purposes.		* @param tag A short name for debugging purposes.

services/core/java/com/android/server/media/MediaSessionService.java

+36 −14

Original line number	Original line	Diff line number	Diff line
	@@ -103,6 +103,7 @@ public class MediaSessionService extends SystemService implements Monitor {

	private static final int WAKELOCK_TIMEOUT = 5000;		private static final int WAKELOCK_TIMEOUT = 5000;
	private static final int MEDIA_KEY_LISTENER_TIMEOUT = 1000;		private static final int MEDIA_KEY_LISTENER_TIMEOUT = 1000;
			private static final int SESSION_CREATION_LIMIT_PER_UID = 100;

	private final Context mContext;		private final Context mContext;
	private final SessionManagerImpl mSessionManagerImpl;		private final SessionManagerImpl mSessionManagerImpl;
	@@ -428,6 +429,18 @@ public class MediaSessionService extends SystemService implements Monitor {
	Log.d(TAG, "Destroying " + session);		Log.d(TAG, "Destroying " + session);
	}		}
	FullUserRecord user = getFullUserRecordLocked(session.getUserId());		FullUserRecord user = getFullUserRecordLocked(session.getUserId());

			if (user != null) {
			final int uid = session.getUid();
			final int sessionCount = user.mUidToSessionCount.get(uid, 0);
			if (sessionCount <= 0) {
			Log.w(TAG, "destroySessionLocked: sessionCount should be positive. "
			+ "sessionCount=" + sessionCount);
			} else {
			user.mUidToSessionCount.put(uid, sessionCount - 1);
			}
			}

	if (mGlobalPrioritySession == session) {		if (mGlobalPrioritySession == session) {
	mGlobalPrioritySession = null;		mGlobalPrioritySession = null;
	if (session.isActive() && user != null) {		if (session.isActive() && user != null) {
	@@ -490,6 +503,20 @@ public class MediaSessionService extends SystemService implements Monitor {
	}		}
	}		}

			private boolean hasMediaControlPermission(int pid, int uid) {
			// Check if it's system server or has MEDIA_CONTENT_CONTROL.
			// Note that system server doesn't have MEDIA_CONTENT_CONTROL, so we need extra
			// check here.
			if (uid == Process.SYSTEM_UID \|\| mContext.checkPermission(
			android.Manifest.permission.MEDIA_CONTENT_CONTROL, pid, uid)
			== PackageManager.PERMISSION_GRANTED) {
			return true;
			} else if (DEBUG) {
			Log.d(TAG, "uid(" + uid + ") hasn't granted MEDIA_CONTENT_CONTROL");
			}
			return false;
			}

	/**		/**
	* This checks if the component is an enabled notification listener for the		* This checks if the component is an enabled notification listener for the
	* specified user. Enabled components may only operate on behalf of the user		* specified user. Enabled components may only operate on behalf of the user
	@@ -544,6 +571,14 @@ public class MediaSessionService extends SystemService implements Monitor {
	throw new RuntimeException("Media Session owner died prematurely.", e);		throw new RuntimeException("Media Session owner died prematurely.", e);
	}		}

			final int sessionCount = user.mUidToSessionCount.get(callerUid, 0);
			if (sessionCount >= SESSION_CREATION_LIMIT_PER_UID
			&& !hasMediaControlPermission(callerPid, callerUid)) {
			throw new RuntimeException("Created too many sessions. count="
			+ sessionCount + ")");
			}
			user.mUidToSessionCount.put(callerUid, sessionCount + 1);

	user.mPriorityStack.addSession(session);		user.mPriorityStack.addSession(session);
	mHandler.postSessionsChanged(session);		mHandler.postSessionsChanged(session);

	@@ -723,6 +758,7 @@ public class MediaSessionService extends SystemService implements Monitor {
	mOnMediaKeyEventDispatchedListeners = new HashMap<>();		mOnMediaKeyEventDispatchedListeners = new HashMap<>();
	private final HashMap<IBinder, OnMediaKeyEventSessionChangedListenerRecord>		private final HashMap<IBinder, OnMediaKeyEventSessionChangedListenerRecord>
	mOnMediaKeyEventSessionChangedListeners = new HashMap<>();		mOnMediaKeyEventSessionChangedListeners = new HashMap<>();
			private final SparseIntArray mUidToSessionCount = new SparseIntArray();

	private PendingIntent mLastMediaButtonReceiver;		private PendingIntent mLastMediaButtonReceiver;
	private ComponentName mRestoredMediaButtonReceiver;		private ComponentName mRestoredMediaButtonReceiver;
	@@ -1954,20 +1990,6 @@ public class MediaSessionService extends SystemService implements Monitor {
	return resolvedUserId;		return resolvedUserId;
	}		}

	private boolean hasMediaControlPermission(int pid, int uid) {
	// Check if it's system server or has MEDIA_CONTENT_CONTROL.
	// Note that system server doesn't have MEDIA_CONTENT_CONTROL, so we need extra
	// check here.
	if (uid == Process.SYSTEM_UID \|\| mContext.checkPermission(
	android.Manifest.permission.MEDIA_CONTENT_CONTROL, pid, uid)
	== PackageManager.PERMISSION_GRANTED) {
	return true;
	} else if (DEBUG) {
	Log.d(TAG, "uid(" + uid + ") hasn't granted MEDIA_CONTENT_CONTROL");
	}
	return false;
	}

	private boolean hasEnabledNotificationListener(int resolvedUserId, String packageName)		private boolean hasEnabledNotificationListener(int resolvedUserId, String packageName)
	throws RemoteException {		throws RemoteException {
	// You may not access another user's content as an enabled listener.		// You may not access another user's content as an enabled listener.