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Store hard refences in a static context and pass through only weak

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references during the Content Capture Sharing.

Motivation: if the remote app is killed, we don't want a possibility of
system server holding a stroing reference (through a reference chain)
to large objects in that app. Therefore what's send in the binder has to
be a weak reference. And we will store a hard reference to those objects
in the client app's static context.

Storing hard references to objects in system_servier is less critical, because that is not going to be killed.

Bug: 148265162
Test: covered by CTS tests
Change-Id: Ie561aab6019d191cf8659fb350e045089e7781ed
(cherry picked from commit 13f65b2974)
This commit is contained in:
Sergey Volnov
2020-02-12 18:19:41 +00:00
parent 810c90c70e
commit 5532c77904
3 changed files with 169 additions and 75 deletions
Download Patch File Download Diff File Expand all files Collapse all files

82
core/java/android/service/contentcapture/ContentCaptureService.java
View File

@@ -60,7 +60,9 @@ import com.android.internal.util.Preconditions;
import java.io.FileDescriptor;
import java.io.PrintWriter;
import java.lang.ref.WeakReference;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.Executor;
import java.util.function.Consumer;
@@ -119,6 +121,9 @@ public abstract class ContentCaptureService extends Service {
*/
public static final String SERVICE_META_DATA = "android.content_capture";
private final LocalDataShareAdapterResourceManager mDataShareAdapterResourceManager =
new LocalDataShareAdapterResourceManager();
private Handler mHandler;
private IContentCaptureServiceCallback mCallback;
@@ -546,7 +551,8 @@ public abstract class ContentCaptureService extends Service {
Preconditions.checkNotNull(executor);
DataShareReadAdapterDelegate delegate =
new DataShareReadAdapterDelegate(executor, adapter);
new DataShareReadAdapterDelegate(executor, adapter,
mDataShareAdapterResourceManager);
try {
callback.accept(delegate);
@@ -653,16 +659,17 @@ public abstract class ContentCaptureService extends Service {
private static class DataShareReadAdapterDelegate extends IDataShareReadAdapter.Stub {
private final WeakReference<LocalDataShareAdapterResourceManager> mResourceManagerReference;
private final Object mLock = new Object();
private final WeakReference<DataShareReadAdapter> mAdapterReference;
private final WeakReference<Executor> mExecutorReference;
DataShareReadAdapterDelegate(Executor executor, DataShareReadAdapter adapter) {
DataShareReadAdapterDelegate(Executor executor, DataShareReadAdapter adapter,
LocalDataShareAdapterResourceManager resourceManager) {
Preconditions.checkNotNull(executor);
Preconditions.checkNotNull(adapter);
Preconditions.checkNotNull(resourceManager);
mExecutorReference = new WeakReference<>(executor);
mAdapterReference = new WeakReference<>(adapter);
resourceManager.initializeForDelegate(this, adapter, executor);
mResourceManagerReference = new WeakReference<>(resourceManager);
}
@Override
@@ -670,6 +677,10 @@ public abstract class ContentCaptureService extends Service {
throws RemoteException {
synchronized (mLock) {
executeAdapterMethodLocked(adapter -> adapter.onStart(fd), "onStart");
// Client app and Service successfully connected, so this object would be kept alive
// until the session has finished.
clearHardReferences();
}
}
@@ -678,16 +689,23 @@ public abstract class ContentCaptureService extends Service {
synchronized (mLock) {
executeAdapterMethodLocked(
adapter -> adapter.onError(errorCode), "onError");
clearHardReferences();
}
}
private void executeAdapterMethodLocked(Consumer<DataShareReadAdapter> adapterFn,
String methodName) {
DataShareReadAdapter adapter = mAdapterReference.get();
Executor executor = mExecutorReference.get();
LocalDataShareAdapterResourceManager resourceManager = mResourceManagerReference.get();
if (resourceManager == null) {
Slog.w(TAG, "Can't execute " + methodName + "(), resource manager has been GC'ed");
return;
}
DataShareReadAdapter adapter = resourceManager.getAdapter(this);
Executor executor = resourceManager.getExecutor(this);
if (adapter == null || executor == null) {
Slog.w(TAG, "Can't execute " + methodName + "(), references have been GC'ed");
Slog.w(TAG, "Can't execute " + methodName + "(), references are null");
return;
}
@@ -698,5 +716,51 @@ public abstract class ContentCaptureService extends Service {
Binder.restoreCallingIdentity(identity);
}
}
private void clearHardReferences() {
LocalDataShareAdapterResourceManager resourceManager = mResourceManagerReference.get();
if (resourceManager == null) {
Slog.w(TAG, "Can't clear references, resource manager has been GC'ed");
return;
}
resourceManager.clearHardReferences(this);
}
}
/**
* Wrapper class making sure dependencies on the current application stay in the application
* context.
*/
private static class LocalDataShareAdapterResourceManager {
// Keeping hard references to the remote objects in the current process (static context)
// to prevent them to be gc'ed during the lifetime of the application. This is an
// artifact of only operating with weak references remotely: there has to be at least 1
// hard reference in order for this to not be killed.
private Map<DataShareReadAdapterDelegate, DataShareReadAdapter>
mDataShareReadAdapterHardReferences = new HashMap<>();
private Map<DataShareReadAdapterDelegate, Executor> mExecutorHardReferences =
new HashMap<>();
void initializeForDelegate(DataShareReadAdapterDelegate delegate,
DataShareReadAdapter adapter, Executor executor) {
mDataShareReadAdapterHardReferences.put(delegate, adapter);
mExecutorHardReferences.remove(delegate, executor);
}
Executor getExecutor(DataShareReadAdapterDelegate delegate) {
return mExecutorHardReferences.get(delegate);
}
DataShareReadAdapter getAdapter(DataShareReadAdapterDelegate delegate) {
return mDataShareReadAdapterHardReferences.get(delegate);
}
void clearHardReferences(DataShareReadAdapterDelegate delegate) {
mDataShareReadAdapterHardReferences.remove(delegate);
mExecutorHardReferences.remove(delegate);
}
}
}

84
core/java/android/view/contentcapture/ContentCaptureManager.java
View File

@@ -54,6 +54,8 @@ import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.Executor;
import java.util.function.Consumer;
@@ -360,6 +362,9 @@ public final class ContentCaptureManager {
@NonNull
private final IContentCaptureManager mService;
@GuardedBy("mLock")
private final LocalDataShareAdapterResourceManager mDataShareAdapterResourceManager;
@NonNull
final ContentCaptureOptions mOptions;
@@ -399,6 +404,8 @@ public final class ContentCaptureManager {
// do, then we should optimize it to run the tests after the Choreographer finishes the most
// important steps of the frame.
mHandler = Handler.createAsync(Looper.getMainLooper());
mDataShareAdapterResourceManager = new LocalDataShareAdapterResourceManager();
}
/**
@@ -681,7 +688,8 @@ public final class ContentCaptureManager {
try {
mService.shareData(request,
new DataShareAdapterDelegate(executor, dataShareWriteAdapter));
new DataShareAdapterDelegate(executor, dataShareWriteAdapter,
mDataShareAdapterResourceManager));
} catch (RemoteException e) {
e.rethrowFromSystemServer();
}
@@ -737,40 +745,53 @@ public final class ContentCaptureManager {
private static class DataShareAdapterDelegate extends IDataShareWriteAdapter.Stub {
private final WeakReference<DataShareWriteAdapter> mAdapterReference;
private final WeakReference<Executor> mExecutorReference;
private final WeakReference<LocalDataShareAdapterResourceManager> mResourceManagerReference;
private DataShareAdapterDelegate(Executor executor, DataShareWriteAdapter adapter) {
private DataShareAdapterDelegate(Executor executor, DataShareWriteAdapter adapter,
LocalDataShareAdapterResourceManager resourceManager) {
Preconditions.checkNotNull(executor);
Preconditions.checkNotNull(adapter);
Preconditions.checkNotNull(resourceManager);
mExecutorReference = new WeakReference<>(executor);
mAdapterReference = new WeakReference<>(adapter);
resourceManager.initializeForDelegate(this, adapter, executor);
mResourceManagerReference = new WeakReference<>(resourceManager);
}
@Override
public void write(ParcelFileDescriptor destination)
throws RemoteException {
executeAdapterMethodLocked(adapter -> adapter.onWrite(destination), "onWrite");
// Client app and Service successfully connected, so this object would be kept alive
// until the session has finished.
clearHardReferences();
}
@Override
public void error(int errorCode) throws RemoteException {
executeAdapterMethodLocked(adapter -> adapter.onError(errorCode), "onError");
clearHardReferences();
}
@Override
public void rejected() throws RemoteException {
executeAdapterMethodLocked(DataShareWriteAdapter::onRejected, "onRejected");
clearHardReferences();
}
private void executeAdapterMethodLocked(Consumer<DataShareWriteAdapter> adapterFn,
String methodName) {
DataShareWriteAdapter adapter = mAdapterReference.get();
Executor executor = mExecutorReference.get();
LocalDataShareAdapterResourceManager resourceManager = mResourceManagerReference.get();
if (resourceManager == null) {
Slog.w(TAG, "Can't execute " + methodName + "(), resource manager has been GC'ed");
return;
}
DataShareWriteAdapter adapter = resourceManager.getAdapter(this);
Executor executor = resourceManager.getExecutor(this);
if (adapter == null || executor == null) {
Slog.w(TAG, "Can't execute " + methodName + "(), references have been GC'ed");
Slog.w(TAG, "Can't execute " + methodName + "(), references are null");
return;
}
@@ -781,5 +802,50 @@ public final class ContentCaptureManager {
Binder.restoreCallingIdentity(identity);
}
}
private void clearHardReferences() {
LocalDataShareAdapterResourceManager resourceManager = mResourceManagerReference.get();
if (resourceManager == null) {
Slog.w(TAG, "Can't clear references, resource manager has been GC'ed");
return;
}
resourceManager.clearHardReferences(this);
}
}
/**
* Wrapper class making sure dependencies on the current application stay in the application
* context.
*/
private static class LocalDataShareAdapterResourceManager {
// Keeping hard references to the remote objects in the current process (static context)
// to prevent them to be gc'ed during the lifetime of the application. This is an
// artifact of only operating with weak references remotely: there has to be at least 1
// hard reference in order for this to not be killed.
private Map<DataShareAdapterDelegate, DataShareWriteAdapter> mWriteAdapterHardReferences =
new HashMap<>();
private Map<DataShareAdapterDelegate, Executor> mExecutorHardReferences =
new HashMap<>();
void initializeForDelegate(DataShareAdapterDelegate delegate, DataShareWriteAdapter adapter,
Executor executor) {
mWriteAdapterHardReferences.put(delegate, adapter);
mExecutorHardReferences.remove(delegate, executor);
}
Executor getExecutor(DataShareAdapterDelegate delegate) {
return mExecutorHardReferences.get(delegate);
}
DataShareWriteAdapter getAdapter(DataShareAdapterDelegate delegate) {
return mWriteAdapterHardReferences.get(delegate);
}
void clearHardReferences(DataShareAdapterDelegate delegate) {
mWriteAdapterHardReferences.remove(delegate);
mExecutorHardReferences.remove(delegate);
}
}
}

78
services/contentcapture/java/com/android/server/contentcapture/ContentCaptureManagerService.java
View File

@@ -89,7 +89,6 @@ import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
@@ -919,35 +918,24 @@ public final class ContentCaptureManagerService extends
private static class DataShareCallbackDelegate extends IDataShareCallback.Stub {
@NonNull private final DataShareRequest mDataShareRequest;
@NonNull private final WeakReference<IDataShareWriteAdapter> mClientAdapterReference;
@NonNull private final WeakReference<ContentCaptureManagerService> mParentServiceReference;
@NonNull private final IDataShareWriteAdapter mClientAdapter;
@NonNull private final ContentCaptureManagerService mParentService;
DataShareCallbackDelegate(@NonNull DataShareRequest dataShareRequest,
@NonNull IDataShareWriteAdapter clientAdapter,
ContentCaptureManagerService parentService) {
mDataShareRequest = dataShareRequest;
mClientAdapterReference = new WeakReference<>(clientAdapter);
mParentServiceReference = new WeakReference<>(parentService);
mClientAdapter = clientAdapter;
mParentService = parentService;
}
@Override
public void accept(IDataShareReadAdapter serviceAdapter) throws RemoteException {
Slog.i(TAG, "Data share request accepted by Content Capture service");
final ContentCaptureManagerService parentService = mParentServiceReference.get();
final IDataShareWriteAdapter clientAdapter = mClientAdapterReference.get();
if (parentService == null || clientAdapter == null) {
Slog.w(TAG, "Can't fulfill accept() request, because remote objects have been "
+ "GC'ed");
return;
}
final WeakReference<IDataShareReadAdapter> serviceAdapterReference =
new WeakReference<>(serviceAdapter);
Pair<ParcelFileDescriptor, ParcelFileDescriptor> clientPipe = createPipe();
if (clientPipe == null) {
clientAdapter.error(ContentCaptureManager.DATA_SHARE_ERROR_UNKNOWN);
mClientAdapter.error(ContentCaptureManager.DATA_SHARE_ERROR_UNKNOWN);
serviceAdapter.error(ContentCaptureManager.DATA_SHARE_ERROR_UNKNOWN);
return;
}
@@ -959,7 +947,7 @@ public final class ContentCaptureManagerService extends
if (servicePipe == null) {
bestEffortCloseFileDescriptors(sourceIn, sinkIn);
clientAdapter.error(ContentCaptureManager.DATA_SHARE_ERROR_UNKNOWN);
mClientAdapter.error(ContentCaptureManager.DATA_SHARE_ERROR_UNKNOWN);
serviceAdapter.error(ContentCaptureManager.DATA_SHARE_ERROR_UNKNOWN);
return;
}
@@ -967,9 +955,9 @@ public final class ContentCaptureManagerService extends
ParcelFileDescriptor sourceOut = servicePipe.second;
ParcelFileDescriptor sinkOut = servicePipe.first;
parentService.mPackagesWithShareRequests.add(mDataShareRequest.getPackageName());
mParentService.mPackagesWithShareRequests.add(mDataShareRequest.getPackageName());
clientAdapter.write(sourceIn);
mClientAdapter.write(sourceIn);
serviceAdapter.start(sinkOut);
// File descriptor received by the client app will be a copy of the current one. Close
@@ -977,7 +965,7 @@ public final class ContentCaptureManagerService extends
// current pipe.
bestEffortCloseFileDescriptor(sourceIn);
parentService.mDataShareExecutor.execute(() -> {
mParentService.mDataShareExecutor.execute(() -> {
try (InputStream fis =
new ParcelFileDescriptor.AutoCloseInputStream(sinkIn);
OutputStream fos =
@@ -996,23 +984,23 @@ public final class ContentCaptureManagerService extends
} catch (IOException e) {
Slog.e(TAG, "Failed to pipe client and service streams", e);
sendErrorSignal(mClientAdapterReference, serviceAdapterReference,
sendErrorSignal(mClientAdapter, serviceAdapter,
ContentCaptureManager.DATA_SHARE_ERROR_UNKNOWN);
} finally {
synchronized (parentService.mLock) {
parentService.mPackagesWithShareRequests
synchronized (mParentService.mLock) {
mParentService.mPackagesWithShareRequests
.remove(mDataShareRequest.getPackageName());
}
}
});
parentService.mHandler.postDelayed(() ->
mParentService.mHandler.postDelayed(() ->
enforceDataSharingTtl(
sourceIn,
sinkIn,
sourceOut,
sinkOut,
serviceAdapterReference),
serviceAdapter),
MAX_DATA_SHARE_FILE_DESCRIPTORS_TTL_MS);
}
@@ -1020,31 +1008,17 @@ public final class ContentCaptureManagerService extends
public void reject() throws RemoteException {
Slog.i(TAG, "Data share request rejected by Content Capture service");
IDataShareWriteAdapter clientAdapter = mClientAdapterReference.get();
if (clientAdapter == null) {
Slog.w(TAG, "Can't fulfill reject() request, because remote objects have been "
+ "GC'ed");
return;
}
clientAdapter.rejected();
mClientAdapter.rejected();
}
private void enforceDataSharingTtl(ParcelFileDescriptor sourceIn,
ParcelFileDescriptor sinkIn,
ParcelFileDescriptor sourceOut,
ParcelFileDescriptor sinkOut,
WeakReference<IDataShareReadAdapter> serviceAdapterReference) {
IDataShareReadAdapter serviceAdapter) {
final ContentCaptureManagerService parentService = mParentServiceReference.get();
if (parentService == null) {
Slog.w(TAG, "Can't enforce data sharing TTL, because remote objects have been "
+ "GC'ed");
return;
}
synchronized (parentService.mLock) {
parentService.mPackagesWithShareRequests
synchronized (mParentService.mLock) {
mParentService.mPackagesWithShareRequests
.remove(mDataShareRequest.getPackageName());
// Interaction finished successfully <=> all data has been written to Content
@@ -1069,7 +1043,7 @@ public final class ContentCaptureManagerService extends
bestEffortCloseFileDescriptors(sourceIn, sinkIn, sourceOut, sinkOut);
if (!finishedSuccessfully) {
sendErrorSignal(mClientAdapterReference, serviceAdapterReference,
sendErrorSignal(mClientAdapter, serviceAdapter,
ContentCaptureManager.DATA_SHARE_ERROR_TIMEOUT_INTERRUPTED);
}
}
@@ -1115,19 +1089,9 @@ public final class ContentCaptureManagerService extends
}
private static void sendErrorSignal(
WeakReference<IDataShareWriteAdapter> clientAdapterReference,
WeakReference<IDataShareReadAdapter> serviceAdapterReference,
IDataShareWriteAdapter clientAdapter,
IDataShareReadAdapter serviceAdapter,
int errorCode) {
final IDataShareWriteAdapter clientAdapter = clientAdapterReference.get();
final IDataShareReadAdapter serviceAdapter = serviceAdapterReference.get();
if (clientAdapter == null || serviceAdapter == null) {
Slog.w(TAG, "Can't propagate error() to read/write data share adapters, because "
+ "remote objects have been GC'ed");
return;
}
try {
clientAdapter.error(errorCode);
} catch (RemoteException e) {