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Commit ec0d7630 authored by Thiébaud Weksteen's avatar Thiébaud Weksteen
Browse files

Add PermissionEnforcer class 

Defines a new PermissionEnforcer class used to check permission as part
of the @EnforcePermission AIDL annotation. It is registered as a system
service to avoid the cost of creating a new object for each new client.

Bug: 234083358
Test: TH
Change-Id: I2bd23f62a0d207ddac6bbe69666ced96e77ba16f
Merged-In: I2bd23f62a0d207ddac6bbe69666ced96e77ba16f
parent f8b2bb52

core/java/android/app/SystemServiceRegistry.java

+9 −0
Original line number Diff line number Diff line
@@ -171,6 +171,7 @@ import android.os.IThermalService; 
import android.os.IUserManager;

import android.os.IncidentManager;

import android.os.PerformanceHintManager;

import android.os.PermissionEnforcer;

import android.os.PowerManager;

import android.os.RecoverySystem;

import android.os.ServiceManager;
@@ -1351,6 +1352,14 @@ public final class SystemServiceRegistry { 
                        return new PermissionCheckerManager(ctx.getOuterContext());

                    }});



        registerService(Context.PERMISSION_ENFORCER_SERVICE, PermissionEnforcer.class,

                new CachedServiceFetcher<PermissionEnforcer>() {

                    @Override

                    public PermissionEnforcer createService(ContextImpl ctx)

                            throws ServiceNotFoundException {

                        return new PermissionEnforcer(ctx.getOuterContext());

                    }});



        registerService(Context.DYNAMIC_SYSTEM_SERVICE, DynamicSystemManager.class,

                new CachedServiceFetcher<DynamicSystemManager>() {

                    @Override

core/java/android/content/Context.java

+8 −0
Original line number Diff line number Diff line
@@ -5134,6 +5134,14 @@ public abstract class Context { 
     */

    public static final String PERMISSION_CHECKER_SERVICE = "permission_checker";



    /**

     * Official published name of the (internal) permission enforcer service.

     *

     * @see #getSystemService(String)

     * @hide

     */

    public static final String PERMISSION_ENFORCER_SERVICE = "permission_enforcer";



    /**

     * Use with {@link #getSystemService(String) to retrieve an

     * {@link android.apphibernation.AppHibernationManager}} for

core/java/android/os/PermissionEnforcer.java

0 → 100644
+101 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2022 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 android.os;



import android.annotation.NonNull;

import android.annotation.SystemService;

import android.content.AttributionSource;

import android.content.Context;

import android.content.PermissionChecker;

import android.permission.PermissionCheckerManager;



/**

 * PermissionEnforcer check permissions for AIDL-generated services which use

 * the @EnforcePermission annotation.

 *

 * <p>AIDL services may be annotated with @EnforcePermission which will trigger

 * the generation of permission check code. This generated code relies on

 * PermissionEnforcer to validate the permissions. The methods available are

 * purposely similar to the AIDL annotation syntax.

 *

 * @see android.permission.PermissionManager

 *

 * @hide

 */

@SystemService(Context.PERMISSION_ENFORCER_SERVICE)

public class PermissionEnforcer {



    private final Context mContext;



    /** Protected constructor. Allows subclasses to instantiate an object

     *  without using a Context.

     */

    protected PermissionEnforcer() {

        mContext = null;

    }



    /** Constructor, prefer using the fromContext static method when possible */

    public PermissionEnforcer(@NonNull Context context) {

        mContext = context;

    }



    @PermissionCheckerManager.PermissionResult

    protected int checkPermission(@NonNull String permission, @NonNull AttributionSource source) {

        return PermissionChecker.checkPermissionForDataDelivery(

            mContext, permission, PermissionChecker.PID_UNKNOWN, source, "" /* message */);

    }



    public void enforcePermission(@NonNull String permission, @NonNull

            AttributionSource source) throws SecurityException {

        int result = checkPermission(permission, source);

        if (result != PermissionCheckerManager.PERMISSION_GRANTED) {

            throw new SecurityException("Access denied, requires: " + permission);

        }

    }



    public void enforcePermissionAllOf(@NonNull String[] permissions,

            @NonNull AttributionSource source) throws SecurityException {

        for (String permission : permissions) {

            int result = checkPermission(permission, source);

            if (result != PermissionCheckerManager.PERMISSION_GRANTED) {

                throw new SecurityException("Access denied, requires: allOf={"

                        + String.join(", ", permissions) + "}");

            }

        }

    }



    public void enforcePermissionAnyOf(@NonNull String[] permissions,

            @NonNull AttributionSource source) throws SecurityException {

        for (String permission : permissions) {

            int result = checkPermission(permission, source);

            if (result == PermissionCheckerManager.PERMISSION_GRANTED) {

                return;

            }

        }

        throw new SecurityException("Access denied, requires: anyOf={"

                + String.join(", ", permissions) + "}");

    }



    /**

     * Returns a new PermissionEnforcer based on a Context.

     *

     * @hide

     */

    public static PermissionEnforcer fromContext(@NonNull Context context) {

        return context.getSystemService(PermissionEnforcer.class);

    }

}