services/companion/java/com/android/server/companion/AssociationRequestsProcessor.java - platform/frameworks/base - Git at Google

 /*
  * Copyright (C) 2021 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 package com.android.server.companion;

 import static android.app.PendingIntent.FLAG_CANCEL_CURRENT;
 import static android.app.PendingIntent.FLAG_IMMUTABLE;
 import static android.app.PendingIntent.FLAG_ONE_SHOT;
 import static android.companion.CompanionDeviceManager.COMPANION_DEVICE_DISCOVERY_PACKAGE_NAME;
 import static android.content.ComponentName.createRelative;

 import static com.android.server.companion.CompanionDeviceManagerService.DEBUG;
 import static com.android.server.companion.CompanionDeviceManagerService.LOG_TAG;
 import static com.android.server.companion.PermissionsUtils.enforcePermissionsForAssociation;
 import static com.android.server.companion.RolesUtils.isRoleHolder;

 import static java.util.Objects.requireNonNull;

 import android.annotation.NonNull;
 import android.annotation.Nullable;
 import android.annotation.UserIdInt;
 import android.app.PendingIntent;
 import android.companion.AssociationInfo;
 import android.companion.AssociationRequest;
 import android.companion.IAssociationRequestCallback;
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentSender;
 import android.content.pm.PackageManagerInternal;
 import android.content.pm.Signature;
 import android.net.MacAddress;
 import android.os.Binder;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.Parcel;
 import android.os.RemoteException;
 import android.os.ResultReceiver;
 import android.util.PackageUtils;
 import android.util.Slog;

 import com.android.internal.util.ArrayUtils;

 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;

 /**
  * Class responsible for handling incoming {@link AssociationRequest}s.
  * The main responsibilities of an {@link AssociationRequestsProcessor} are:
  * <ul>
  * <li> Requests validation and checking if the package that would own the association holds all
  * necessary permissions.
  * <li> Communication with the requester via a provided
  * {@link android.companion.CompanionDeviceManager.Callback}.
  * <li> Constructing an {@link Intent} for collecting user's approval (if needed), and handling the
  * approval.
  * <li> Calling to {@link CompanionDeviceManagerService} to create an association when/if the
  * request was found valid and was approved by user.
  * </ul>
  *
  * The class supports two variants of the "Association Flow": the full variant, and the shortened
  * (a.k.a. No-UI) variant.
  * Both flows start similarly: in
  * {@link #processNewAssociationRequest(AssociationRequest, String, int, IAssociationRequestCallback)}
  * invoked from
  * {@link CompanionDeviceManagerService.CompanionDeviceManagerImpl#associate(AssociationRequest, IAssociationRequestCallback, String, int)}
  * method call.
  * Then an {@link AssociationRequestsProcessor} makes a decision whether user's confirmation is
  * required.
  *
  * If the user's approval is NOT required: an {@link AssociationRequestsProcessor} invokes
  * {@link #createAssociationAndNotifyApplication(AssociationRequest, String, int, MacAddress, IAssociationRequestCallback)}
  * which after calling to  {@link CompanionDeviceManagerService} to create an association, notifies
  * the requester via
  * {@link android.companion.CompanionDeviceManager.Callback#onAssociationCreated(AssociationInfo)}.
  *
  * If the user's approval is required: an {@link AssociationRequestsProcessor} constructs a
  * {@link PendingIntent} for the approval UI and sends it back to the requester via
  * {@link android.companion.CompanionDeviceManager.Callback#onAssociationPending(IntentSender)}.
  * When/if user approves the request,  {@link AssociationRequestsProcessor} receives a "callback"
  * from the Approval UI in via {@link #mOnRequestConfirmationReceiver} and invokes
  * {@link #processAssociationRequestApproval(AssociationRequest, IAssociationRequestCallback, ResultReceiver, MacAddress)}
  * which one more time checks that the packages holds all necessary permissions before proceeding to
  * {@link #createAssociationAndNotifyApplication(AssociationRequest, String, int, MacAddress, IAssociationRequestCallback)}.
  *
  * @see #processNewAssociationRequest(AssociationRequest, String, int, IAssociationRequestCallback)
  * @see #processAssociationRequestApproval(AssociationRequest, IAssociationRequestCallback,
  * ResultReceiver, MacAddress)
  */
 class AssociationRequestsProcessor {
     private static final String TAG = LOG_TAG + ".AssociationRequestsProcessor";

     private static final ComponentName ASSOCIATION_REQUEST_APPROVAL_ACTIVITY =
             createRelative(COMPANION_DEVICE_DISCOVERY_PACKAGE_NAME, ".CompanionDeviceActivity");

     // AssociationRequestsProcessor <-> UI
     private static final String EXTRA_APPLICATION_CALLBACK = "application_callback";
     private static final String EXTRA_ASSOCIATION_REQUEST = "association_request";
     private static final String EXTRA_RESULT_RECEIVER = "result_receiver";

     // AssociationRequestsProcessor -> UI
     private static final int RESULT_CODE_ASSOCIATION_CREATED = 0;
     private static final String EXTRA_ASSOCIATION = "association";

     // UI -> AssociationRequestsProcessor
     private static final int RESULT_CODE_ASSOCIATION_APPROVED = 0;
     private static final String EXTRA_MAC_ADDRESS = "mac_address";

     private static final int ASSOCIATE_WITHOUT_PROMPT_MAX_PER_TIME_WINDOW = 5;
     private static final long ASSOCIATE_WITHOUT_PROMPT_WINDOW_MS = 60 * 60 * 1000; // 60 min;

     private final @NonNull Context mContext;
     private final @NonNull CompanionDeviceManagerService mService;
     private final @NonNull PackageManagerInternal mPackageManager;
     private final @NonNull AssociationStore mAssociationStore;

     AssociationRequestsProcessor(@NonNull CompanionDeviceManagerService service,
             @NonNull AssociationStore associationStore) {
         mContext = service.getContext();
         mService = service;
         mPackageManager = service.mPackageManagerInternal;
         mAssociationStore = associationStore;
     }

     /**
      * Handle incoming {@link AssociationRequest}s, sent via
      * {@link android.companion.ICompanionDeviceManager#associate(AssociationRequest, IAssociationRequestCallback, String, int)}
      */
     void processNewAssociationRequest(@NonNull AssociationRequest request,
             @NonNull String packageName, @UserIdInt int userId,
             @NonNull IAssociationRequestCallback callback) {
         requireNonNull(request, "Request MUST NOT be null");
         if (request.isSelfManaged()) {
             requireNonNull(request.getDisplayName(), "AssociationRequest.displayName "
                     + "MUST NOT be null.");
         }
         requireNonNull(packageName, "Package name MUST NOT be null");
         requireNonNull(callback, "Callback MUST NOT be null");

         final int packageUid = mPackageManager.getPackageUid(packageName, 0, userId);
         if (DEBUG) {
             Slog.d(TAG, "processNewAssociationRequest() "
                     + "request=" + request + ", "
                     + "package=u" + userId + "/" + packageName + " (uid=" + packageUid + ")");
         }

         // 1. Enforce permissions and other requirements.
         enforcePermissionsForAssociation(mContext, request, packageUid);
         mService.checkUsesFeature(packageName, userId);

         // 2. Check if association can be created without launching UI (i.e. CDM needs NEITHER
         // to perform discovery NOR to collect user consent).
         if (request.isSelfManaged() && !request.isForceConfirmation()
                 && !willAddRoleHolder(request, packageName, userId)) {
             // 2a. Create association right away.
             createAssociationAndNotifyApplication(request, packageName, userId,
                     /*macAddress*/ null, callback);
             return;
         }

         // 2b. Build a PendingIntent for launching the confirmation UI, and send it back to the app:

         // 2b.1. Populate the request with required info.
         request.setPackageName(packageName);
         request.setUserId(userId);
         request.setSkipPrompt(mayAssociateWithoutPrompt(request, packageName, userId));

         // 2b.2. Prepare extras and create an Intent.
         final Bundle extras = new Bundle();
         extras.putParcelable(EXTRA_ASSOCIATION_REQUEST, request);
         extras.putBinder(EXTRA_APPLICATION_CALLBACK, callback.asBinder());
         extras.putParcelable(EXTRA_RESULT_RECEIVER, prepareForIpc(mOnRequestConfirmationReceiver));

         final Intent intent = new Intent();
         intent.setComponent(ASSOCIATION_REQUEST_APPROVAL_ACTIVITY);
         intent.putExtras(extras);

         // 2b.3. Create a PendingIntent.
         final PendingIntent pendingIntent;
         final long token = Binder.clearCallingIdentity();
         try {
             // Using uid of the application that will own the association (usually the same
             // application that sent the request) allows us to have multiple "pending" association
             // requests at the same time.
             // If the application already has a pending association request, that PendingIntent
             // will be cancelled.
             pendingIntent = PendingIntent.getActivity(mContext, /*requestCode */ packageUid, intent,
                     FLAG_ONE_SHOT | FLAG_CANCEL_CURRENT | FLAG_IMMUTABLE);
         } finally {
             Binder.restoreCallingIdentity(token);
         }

         // 2b.4. Send the PendingIntent back to the app.
         try {
             callback.onAssociationPending(pendingIntent);
         } catch (RemoteException ignore) { }
     }

     private void processAssociationRequestApproval(@NonNull AssociationRequest request,
             @NonNull IAssociationRequestCallback callback,
             @NonNull ResultReceiver resultReceiver, @Nullable MacAddress macAddress) {
         final String packageName = request.getPackageName();
         final int userId = request.getUserId();
         final int packageUid = mPackageManager.getPackageUid(packageName, 0, userId);

         if (DEBUG) {
             Slog.d(TAG, "processAssociationRequestApproval()\n"
                     + "   package=u" + userId + "/" + packageName + " (uid=" + packageUid + ")\n"
                     + "   request=" + request + "\n"
                     + "   macAddress=" + macAddress + "\n");
         }

         // 1. Need to check permissions again in case something changed, since we first received
         // this request.
         try {
             enforcePermissionsForAssociation(mContext, request, packageUid);
         } catch (SecurityException e) {
             // Since, at this point the caller is our own UI, we need to catch the exception on
             // forward it back to the application via the callback.
             try {
                 callback.onFailure(e.getMessage());
             } catch (RemoteException ignore) { }
             return;
         }

         // 2. Create association and notify the application.
         final AssociationInfo association = createAssociationAndNotifyApplication(
                 request, packageName, userId, macAddress, callback);

         // 3. Send the association back the Approval Activity, so that it can report back to the app
         // via Activity.setResult().
         final Bundle data = new Bundle();
         data.putParcelable(EXTRA_ASSOCIATION, association);
         resultReceiver.send(RESULT_CODE_ASSOCIATION_CREATED, data);
     }

     private AssociationInfo createAssociationAndNotifyApplication(
             @NonNull AssociationRequest request, @NonNull String packageName, @UserIdInt int userId,
             @Nullable MacAddress macAddress, @NonNull IAssociationRequestCallback callback) {
         final AssociationInfo association = mService.createAssociation(userId, packageName,
                 macAddress, request.getDisplayName(), request.getDeviceProfile(),
                 request.isSelfManaged());

         try {
             callback.onAssociationCreated(association);
         } catch (RemoteException ignore) { }

         return association;
     }

     private boolean willAddRoleHolder(@NonNull AssociationRequest request,
             @NonNull String packageName, @UserIdInt int userId) {
         final String deviceProfile = request.getDeviceProfile();
         if (deviceProfile == null) return false;

         final boolean isRoleHolder = Binder.withCleanCallingIdentity(
                 () -> isRoleHolder(mContext, userId, packageName, deviceProfile));

         // Don't need to "grant" the role, if the package already holds the role.
         return !isRoleHolder;
     }

     private final ResultReceiver mOnRequestConfirmationReceiver =
             new ResultReceiver(Handler.getMain()) {
         @Override
         protected void onReceiveResult(int resultCode, Bundle data) {
             if (DEBUG) {
                 Slog.d(TAG, "mOnRequestConfirmationReceiver.onReceiveResult() "
                         + "code=" + resultCode + ", " + "data=" + data);
             }

             if (resultCode != RESULT_CODE_ASSOCIATION_APPROVED) {
                 Slog.w(TAG, "Unknown result code:" + resultCode);
                 return;
             }

             final AssociationRequest request = data.getParcelable(EXTRA_ASSOCIATION_REQUEST);
             final IAssociationRequestCallback callback = IAssociationRequestCallback.Stub
                     .asInterface(data.getBinder(EXTRA_APPLICATION_CALLBACK));
             final ResultReceiver resultReceiver = data.getParcelable(EXTRA_RESULT_RECEIVER);

             requireNonNull(request);
             requireNonNull(callback);
             requireNonNull(resultReceiver);

             final MacAddress macAddress;
             if (request.isSelfManaged()) {
                 macAddress = null;
             } else {
                 macAddress = data.getParcelable(EXTRA_MAC_ADDRESS);
                 requireNonNull(macAddress);
             }

             processAssociationRequestApproval(request, callback, resultReceiver, macAddress);
         }
     };

     private boolean mayAssociateWithoutPrompt(@NonNull AssociationRequest request,
             @NonNull String packageName, @UserIdInt int userId) {
         final String deviceProfile = request.getDeviceProfile();
         if (deviceProfile != null) {
             final boolean isRoleHolder = Binder.withCleanCallingIdentity(
                     () -> isRoleHolder(mContext, userId, packageName, deviceProfile));
             if (isRoleHolder) {
                 // Don't need to collect user's consent since app already holds the role.
                 return true;
             }
         }

         String[] sameOemPackages = mContext.getResources()
                 .getStringArray(com.android.internal.R.array.config_companionDevicePackages);
         if (!ArrayUtils.contains(sameOemPackages, packageName)) {
             Slog.w(TAG, packageName
                     + " can not silently create associations due to no package found."
                     + " Packages from OEM: " + Arrays.toString(sameOemPackages)
             );
             return false;
         }

         // Throttle frequent associations
         final long now = System.currentTimeMillis();
         final List<AssociationInfo> associationForPackage =
                 mAssociationStore.getAssociationsForPackage(userId, packageName);
         // Number of "recent" associations.
         int recent = 0;
         for (AssociationInfo association : associationForPackage) {
             final boolean isRecent =
                     now - association.getTimeApprovedMs() < ASSOCIATE_WITHOUT_PROMPT_WINDOW_MS;
             if (isRecent) {
                 if (++recent >= ASSOCIATE_WITHOUT_PROMPT_MAX_PER_TIME_WINDOW) {
                     Slog.w(TAG, "Too many associations: " + packageName + " already "
                             + "associated " + recent + " devices within the last "
                             + ASSOCIATE_WITHOUT_PROMPT_WINDOW_MS + "ms");
                     return false;
                 }
             }
         }

         String[] sameOemCerts = mContext.getResources()
                 .getStringArray(com.android.internal.R.array.config_companionDeviceCerts);

         Signature[] signatures = mPackageManager.getPackage(packageName).getSigningDetails()
                 .getSignatures();
         String[] apkCerts = PackageUtils.computeSignaturesSha256Digests(signatures);

         Set<String> sameOemPackageCerts =
                 getSameOemPackageCerts(packageName, sameOemPackages, sameOemCerts);

         for (String cert : apkCerts) {
             if (sameOemPackageCerts.contains(cert)) {
                 return true;
             }
         }

         Slog.w(TAG, packageName
                 + " can not silently create associations. " + packageName
                 + " has SHA256 certs from APK: " + Arrays.toString(apkCerts)
                 + " and from OEM: " + Arrays.toString(sameOemCerts)
         );

         return false;
     }

     private static Set<String> getSameOemPackageCerts(
             String packageName, String[] oemPackages, String[] sameOemCerts) {
         Set<String> sameOemPackageCerts = new HashSet<>();

         // Assume OEM may enter same package name in the parallel string array with
         // multiple APK certs corresponding to it
         for (int i = 0; i < oemPackages.length; i++) {
             if (oemPackages[i].equals(packageName)) {
                 sameOemPackageCerts.add(sameOemCerts[i].replaceAll(":", ""));
             }
         }

         return sameOemPackageCerts;
     }

     /**
      * Convert an instance of a "locally-defined" ResultReceiver to an instance of
      * {@link android.os.ResultReceiver} itself, which the receiving process will be able to
      * unmarshall.
      */
     private static <T extends ResultReceiver> ResultReceiver prepareForIpc(T resultReceiver) {
         final Parcel parcel = Parcel.obtain();
         resultReceiver.writeToParcel(parcel, 0);
         parcel.setDataPosition(0);

         final ResultReceiver ipcFriendly = ResultReceiver.CREATOR.createFromParcel(parcel);
         parcel.recycle();

         return ipcFriendly;
     }
 }
	/*
	* Copyright (C) 2021 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	package com.android.server.companion;

	import static android.app.PendingIntent.FLAG_CANCEL_CURRENT;
	import static android.app.PendingIntent.FLAG_IMMUTABLE;
	import static android.app.PendingIntent.FLAG_ONE_SHOT;
	import static android.companion.CompanionDeviceManager.COMPANION_DEVICE_DISCOVERY_PACKAGE_NAME;
	import static android.content.ComponentName.createRelative;

	import static com.android.server.companion.CompanionDeviceManagerService.DEBUG;
	import static com.android.server.companion.CompanionDeviceManagerService.LOG_TAG;
	import static com.android.server.companion.PermissionsUtils.enforcePermissionsForAssociation;
	import static com.android.server.companion.RolesUtils.isRoleHolder;

	import static java.util.Objects.requireNonNull;

	import android.annotation.NonNull;
	import android.annotation.Nullable;
	import android.annotation.UserIdInt;
	import android.app.PendingIntent;
	import android.companion.AssociationInfo;
	import android.companion.AssociationRequest;
	import android.companion.IAssociationRequestCallback;
	import android.content.ComponentName;
	import android.content.Context;
	import android.content.Intent;
	import android.content.IntentSender;
	import android.content.pm.PackageManagerInternal;
	import android.content.pm.Signature;
	import android.net.MacAddress;
	import android.os.Binder;
	import android.os.Bundle;
	import android.os.Handler;
	import android.os.Parcel;
	import android.os.RemoteException;
	import android.os.ResultReceiver;
	import android.util.PackageUtils;
	import android.util.Slog;

	import com.android.internal.util.ArrayUtils;

	import java.util.Arrays;
	import java.util.HashSet;
	import java.util.List;
	import java.util.Set;

	/**
	* Class responsible for handling incoming {@link AssociationRequest}s.
	* The main responsibilities of an {@link AssociationRequestsProcessor} are:
	* <ul>
	* <li> Requests validation and checking if the package that would own the association holds all
	* necessary permissions.
	* <li> Communication with the requester via a provided
	* {@link android.companion.CompanionDeviceManager.Callback}.
	* <li> Constructing an {@link Intent} for collecting user's approval (if needed), and handling the
	* approval.
	* <li> Calling to {@link CompanionDeviceManagerService} to create an association when/if the
	* request was found valid and was approved by user.
	* </ul>
	*
	* The class supports two variants of the "Association Flow": the full variant, and the shortened
	* (a.k.a. No-UI) variant.
	* Both flows start similarly: in
	* {@link #processNewAssociationRequest(AssociationRequest, String, int, IAssociationRequestCallback)}
	* invoked from
	* {@link CompanionDeviceManagerService.CompanionDeviceManagerImpl#associate(AssociationRequest, IAssociationRequestCallback, String, int)}
	* method call.
	* Then an {@link AssociationRequestsProcessor} makes a decision whether user's confirmation is
	* required.
	*
	* If the user's approval is NOT required: an {@link AssociationRequestsProcessor} invokes
	* {@link #createAssociationAndNotifyApplication(AssociationRequest, String, int, MacAddress, IAssociationRequestCallback)}
	* which after calling to {@link CompanionDeviceManagerService} to create an association, notifies
	* the requester via
	* {@link android.companion.CompanionDeviceManager.Callback#onAssociationCreated(AssociationInfo)}.
	*
	* If the user's approval is required: an {@link AssociationRequestsProcessor} constructs a
	* {@link PendingIntent} for the approval UI and sends it back to the requester via
	* {@link android.companion.CompanionDeviceManager.Callback#onAssociationPending(IntentSender)}.
	* When/if user approves the request, {@link AssociationRequestsProcessor} receives a "callback"
	* from the Approval UI in via {@link #mOnRequestConfirmationReceiver} and invokes
	* {@link #processAssociationRequestApproval(AssociationRequest, IAssociationRequestCallback, ResultReceiver, MacAddress)}
	* which one more time checks that the packages holds all necessary permissions before proceeding to
	* {@link #createAssociationAndNotifyApplication(AssociationRequest, String, int, MacAddress, IAssociationRequestCallback)}.
	*
	* @see #processNewAssociationRequest(AssociationRequest, String, int, IAssociationRequestCallback)
	* @see #processAssociationRequestApproval(AssociationRequest, IAssociationRequestCallback,
	* ResultReceiver, MacAddress)
	*/
	class AssociationRequestsProcessor {
	private static final String TAG = LOG_TAG + ".AssociationRequestsProcessor";

	private static final ComponentName ASSOCIATION_REQUEST_APPROVAL_ACTIVITY =
	createRelative(COMPANION_DEVICE_DISCOVERY_PACKAGE_NAME, ".CompanionDeviceActivity");

	// AssociationRequestsProcessor <-> UI
	private static final String EXTRA_APPLICATION_CALLBACK = "application_callback";
	private static final String EXTRA_ASSOCIATION_REQUEST = "association_request";
	private static final String EXTRA_RESULT_RECEIVER = "result_receiver";

	// AssociationRequestsProcessor -> UI
	private static final int RESULT_CODE_ASSOCIATION_CREATED = 0;
	private static final String EXTRA_ASSOCIATION = "association";

	// UI -> AssociationRequestsProcessor
	private static final int RESULT_CODE_ASSOCIATION_APPROVED = 0;
	private static final String EXTRA_MAC_ADDRESS = "mac_address";

	private static final int ASSOCIATE_WITHOUT_PROMPT_MAX_PER_TIME_WINDOW = 5;
	private static final long ASSOCIATE_WITHOUT_PROMPT_WINDOW_MS = 60 * 60 * 1000; // 60 min;

	private final @NonNull Context mContext;
	private final @NonNull CompanionDeviceManagerService mService;
	private final @NonNull PackageManagerInternal mPackageManager;
	private final @NonNull AssociationStore mAssociationStore;

	AssociationRequestsProcessor(@NonNull CompanionDeviceManagerService service,
	@NonNull AssociationStore associationStore) {
	mContext = service.getContext();
	mService = service;
	mPackageManager = service.mPackageManagerInternal;
	mAssociationStore = associationStore;
	}

	/**
	* Handle incoming {@link AssociationRequest}s, sent via
	* {@link android.companion.ICompanionDeviceManager#associate(AssociationRequest, IAssociationRequestCallback, String, int)}
	*/
	void processNewAssociationRequest(@NonNull AssociationRequest request,
	@NonNull String packageName, @UserIdInt int userId,
	@NonNull IAssociationRequestCallback callback) {
	requireNonNull(request, "Request MUST NOT be null");
	if (request.isSelfManaged()) {
	requireNonNull(request.getDisplayName(), "AssociationRequest.displayName "
	+ "MUST NOT be null.");
	}
	requireNonNull(packageName, "Package name MUST NOT be null");
	requireNonNull(callback, "Callback MUST NOT be null");

	final int packageUid = mPackageManager.getPackageUid(packageName, 0, userId);
	if (DEBUG) {
	Slog.d(TAG, "processNewAssociationRequest() "
	+ "request=" + request + ", "
	+ "package=u" + userId + "/" + packageName + " (uid=" + packageUid + ")");
	}

	// 1. Enforce permissions and other requirements.
	enforcePermissionsForAssociation(mContext, request, packageUid);
	mService.checkUsesFeature(packageName, userId);

	// 2. Check if association can be created without launching UI (i.e. CDM needs NEITHER
	// to perform discovery NOR to collect user consent).
	if (request.isSelfManaged() && !request.isForceConfirmation()
	&& !willAddRoleHolder(request, packageName, userId)) {
	// 2a. Create association right away.
	createAssociationAndNotifyApplication(request, packageName, userId,
	/macAddress/ null, callback);
	return;
	}

	// 2b. Build a PendingIntent for launching the confirmation UI, and send it back to the app:

	// 2b.1. Populate the request with required info.
	request.setPackageName(packageName);
	request.setUserId(userId);
	request.setSkipPrompt(mayAssociateWithoutPrompt(request, packageName, userId));

	// 2b.2. Prepare extras and create an Intent.
	final Bundle extras = new Bundle();
	extras.putParcelable(EXTRA_ASSOCIATION_REQUEST, request);
	extras.putBinder(EXTRA_APPLICATION_CALLBACK, callback.asBinder());
	extras.putParcelable(EXTRA_RESULT_RECEIVER, prepareForIpc(mOnRequestConfirmationReceiver));

	final Intent intent = new Intent();
	intent.setComponent(ASSOCIATION_REQUEST_APPROVAL_ACTIVITY);
	intent.putExtras(extras);

	// 2b.3. Create a PendingIntent.
	final PendingIntent pendingIntent;
	final long token = Binder.clearCallingIdentity();
	try {
	// Using uid of the application that will own the association (usually the same
	// application that sent the request) allows us to have multiple "pending" association
	// requests at the same time.
	// If the application already has a pending association request, that PendingIntent
	// will be cancelled.
	pendingIntent = PendingIntent.getActivity(mContext, /requestCode / packageUid, intent,
	FLAG_ONE_SHOT \| FLAG_CANCEL_CURRENT \| FLAG_IMMUTABLE);
	} finally {
	Binder.restoreCallingIdentity(token);
	}

	// 2b.4. Send the PendingIntent back to the app.
	try {
	callback.onAssociationPending(pendingIntent);
	} catch (RemoteException ignore) { }
	}

	private void processAssociationRequestApproval(@NonNull AssociationRequest request,
	@NonNull IAssociationRequestCallback callback,
	@NonNull ResultReceiver resultReceiver, @Nullable MacAddress macAddress) {
	final String packageName = request.getPackageName();
	final int userId = request.getUserId();
	final int packageUid = mPackageManager.getPackageUid(packageName, 0, userId);

	if (DEBUG) {
	Slog.d(TAG, "processAssociationRequestApproval()\n"
	+ " package=u" + userId + "/" + packageName + " (uid=" + packageUid + ")\n"
	+ " request=" + request + "\n"
	+ " macAddress=" + macAddress + "\n");
	}

	// 1. Need to check permissions again in case something changed, since we first received
	// this request.
	try {
	enforcePermissionsForAssociation(mContext, request, packageUid);
	} catch (SecurityException e) {
	// Since, at this point the caller is our own UI, we need to catch the exception on
	// forward it back to the application via the callback.
	try {
	callback.onFailure(e.getMessage());
	} catch (RemoteException ignore) { }
	return;
	}

	// 2. Create association and notify the application.
	final AssociationInfo association = createAssociationAndNotifyApplication(
	request, packageName, userId, macAddress, callback);

	// 3. Send the association back the Approval Activity, so that it can report back to the app
	// via Activity.setResult().
	final Bundle data = new Bundle();
	data.putParcelable(EXTRA_ASSOCIATION, association);
	resultReceiver.send(RESULT_CODE_ASSOCIATION_CREATED, data);
	}

	private AssociationInfo createAssociationAndNotifyApplication(
	@NonNull AssociationRequest request, @NonNull String packageName, @UserIdInt int userId,
	@Nullable MacAddress macAddress, @NonNull IAssociationRequestCallback callback) {
	final AssociationInfo association = mService.createAssociation(userId, packageName,
	macAddress, request.getDisplayName(), request.getDeviceProfile(),
	request.isSelfManaged());

	try {
	callback.onAssociationCreated(association);
	} catch (RemoteException ignore) { }

	return association;
	}

	private boolean willAddRoleHolder(@NonNull AssociationRequest request,
	@NonNull String packageName, @UserIdInt int userId) {
	final String deviceProfile = request.getDeviceProfile();
	if (deviceProfile == null) return false;

	final boolean isRoleHolder = Binder.withCleanCallingIdentity(
	() -> isRoleHolder(mContext, userId, packageName, deviceProfile));

	// Don't need to "grant" the role, if the package already holds the role.
	return !isRoleHolder;
	}

	private final ResultReceiver mOnRequestConfirmationReceiver =
	new ResultReceiver(Handler.getMain()) {
	@Override
	protected void onReceiveResult(int resultCode, Bundle data) {
	if (DEBUG) {
	Slog.d(TAG, "mOnRequestConfirmationReceiver.onReceiveResult() "
	+ "code=" + resultCode + ", " + "data=" + data);
	}

	if (resultCode != RESULT_CODE_ASSOCIATION_APPROVED) {
	Slog.w(TAG, "Unknown result code:" + resultCode);
	return;
	}

	final AssociationRequest request = data.getParcelable(EXTRA_ASSOCIATION_REQUEST);
	final IAssociationRequestCallback callback = IAssociationRequestCallback.Stub
	.asInterface(data.getBinder(EXTRA_APPLICATION_CALLBACK));
	final ResultReceiver resultReceiver = data.getParcelable(EXTRA_RESULT_RECEIVER);

	requireNonNull(request);
	requireNonNull(callback);
	requireNonNull(resultReceiver);

	final MacAddress macAddress;
	if (request.isSelfManaged()) {
	macAddress = null;
	} else {
	macAddress = data.getParcelable(EXTRA_MAC_ADDRESS);
	requireNonNull(macAddress);
	}

	processAssociationRequestApproval(request, callback, resultReceiver, macAddress);
	}
	};

	private boolean mayAssociateWithoutPrompt(@NonNull AssociationRequest request,
	@NonNull String packageName, @UserIdInt int userId) {
	final String deviceProfile = request.getDeviceProfile();
	if (deviceProfile != null) {
	final boolean isRoleHolder = Binder.withCleanCallingIdentity(
	() -> isRoleHolder(mContext, userId, packageName, deviceProfile));
	if (isRoleHolder) {
	// Don't need to collect user's consent since app already holds the role.
	return true;
	}
	}

	String[] sameOemPackages = mContext.getResources()
	.getStringArray(com.android.internal.R.array.config_companionDevicePackages);
	if (!ArrayUtils.contains(sameOemPackages, packageName)) {
	Slog.w(TAG, packageName
	+ " can not silently create associations due to no package found."
	+ " Packages from OEM: " + Arrays.toString(sameOemPackages)
	);
	return false;
	}

	// Throttle frequent associations
	final long now = System.currentTimeMillis();
	final List<AssociationInfo> associationForPackage =
	mAssociationStore.getAssociationsForPackage(userId, packageName);
	// Number of "recent" associations.
	int recent = 0;
	for (AssociationInfo association : associationForPackage) {
	final boolean isRecent =
	now - association.getTimeApprovedMs() < ASSOCIATE_WITHOUT_PROMPT_WINDOW_MS;
	if (isRecent) {
	if (++recent >= ASSOCIATE_WITHOUT_PROMPT_MAX_PER_TIME_WINDOW) {
	Slog.w(TAG, "Too many associations: " + packageName + " already "
	+ "associated " + recent + " devices within the last "
	+ ASSOCIATE_WITHOUT_PROMPT_WINDOW_MS + "ms");
	return false;
	}
	}
	}

	String[] sameOemCerts = mContext.getResources()
	.getStringArray(com.android.internal.R.array.config_companionDeviceCerts);

	Signature[] signatures = mPackageManager.getPackage(packageName).getSigningDetails()
	.getSignatures();
	String[] apkCerts = PackageUtils.computeSignaturesSha256Digests(signatures);

	Set<String> sameOemPackageCerts =
	getSameOemPackageCerts(packageName, sameOemPackages, sameOemCerts);

	for (String cert : apkCerts) {
	if (sameOemPackageCerts.contains(cert)) {
	return true;
	}
	}

	Slog.w(TAG, packageName
	+ " can not silently create associations. " + packageName
	+ " has SHA256 certs from APK: " + Arrays.toString(apkCerts)
	+ " and from OEM: " + Arrays.toString(sameOemCerts)
	);

	return false;
	}

	private static Set<String> getSameOemPackageCerts(
	String packageName, String[] oemPackages, String[] sameOemCerts) {
	Set<String> sameOemPackageCerts = new HashSet<>();

	// Assume OEM may enter same package name in the parallel string array with
	// multiple APK certs corresponding to it
	for (int i = 0; i < oemPackages.length; i++) {
	if (oemPackages[i].equals(packageName)) {
	sameOemPackageCerts.add(sameOemCerts[i].replaceAll(":", ""));
	}
	}

	return sameOemPackageCerts;
	}

	/**
	* Convert an instance of a "locally-defined" ResultReceiver to an instance of
	* {@link android.os.ResultReceiver} itself, which the receiving process will be able to
	* unmarshall.
	*/
	private static <T extends ResultReceiver> ResultReceiver prepareForIpc(T resultReceiver) {
	final Parcel parcel = Parcel.obtain();
	resultReceiver.writeToParcel(parcel, 0);
	parcel.setDataPosition(0);

	final ResultReceiver ipcFriendly = ResultReceiver.CREATOR.createFromParcel(parcel);
	parcel.recycle();

	return ipcFriendly;
	}
	}