Add precondition checks (af1c3cb4) · Commits · e / os / android_frameworks_base

core/java/com/android/internal/util/Preconditions.java

+26 −0

Original line number	Diff line number	Diff line
		@@ -186,6 +186,32 @@ public class Preconditions {
		checkState(expression, null);
		}

		/**
		* Ensures the truth of an expression involving whether the calling identity is authorized to
		* call the calling method.
		*
		* @param expression a boolean expression
		* @throws SecurityException if {@code expression} is false
		*/
		public static void checkCallAuthorization(final boolean expression) {
		if (!expression) {
		throw new SecurityException("Calling identity is not authorized");
		}
		}

		/**
		* Ensures the truth of an expression involving whether the calling user is authorized to
		* call the calling method.
		*
		* @param expression a boolean expression
		* @throws SecurityException if {@code expression} is false
		*/
		public static void checkCallingUser(final boolean expression) {
		if (!expression) {
		throw new SecurityException("Calling user is not authorized");
		}
		}

		/**
		* Check the requested flags, throwing if any requested flags are outside
		* the allowed set.

services/devicepolicy/java/com/android/server/devicepolicy/CallerIdentity.java

0 → 100644

+61 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2020 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.devicepolicy;

		import android.annotation.Nullable;
		import android.content.ComponentName;
		import android.os.UserHandle;

		/**
		* Caller identity containing the caller's UID, package name and component name.
		* All parameters are verified on object creation unless the component name is null and the
		* caller is a delegate.
		*/
		class CallerIdentity {

		private final int mUid;
		@Nullable
		private final String mPackageName;
		@Nullable
		private final ComponentName mComponentName;

		CallerIdentity(int uid, @Nullable String packageName, @Nullable ComponentName componentName) {
		mUid = uid;
		mPackageName = packageName;
		mComponentName = componentName;
		}

		public int getUid() {
		return mUid;
		}

		public int getUserId() {
		return UserHandle.getUserId(mUid);
		}

		public UserHandle getUserHandle() {
		return UserHandle.getUserHandleForUid(mUid);
		}

		@Nullable public String getPackageName() {
		return mPackageName;
		}

		@Nullable public ComponentName getComponentName() {
		return mComponentName;
		}
		}

services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerService.java

+48 −7

Original line number	Diff line number	Diff line
		@@ -2701,6 +2701,39 @@ public class DevicePolicyManagerService extends BaseIDevicePolicyManager {
		}
		}

		/**
		* Creates a new {@link CallerIdentity} object to represent the caller's identity.
		*/
		private CallerIdentity getCallerIdentity(String callerPackage) {
		final int callerUid = mInjector.binderGetCallingUid();

		if (!isCallingFromPackage(callerPackage, callerUid)) {
		throw new SecurityException(
		String.format("Caller with uid %d is not %s", callerUid, callerPackage));
		}

		return new CallerIdentity(callerUid, callerPackage, null);
		}

		/**
		* Creates a new {@link CallerIdentity} object to represent the caller's identity.
		*/
		private CallerIdentity getCallerIdentity(@NonNull ComponentName componentName) {
		final int callerUid = mInjector.binderGetCallingUid();
		final DevicePolicyData policy = getUserData(UserHandle.getUserId(callerUid));
		ActiveAdmin admin = policy.mAdminMap.get(componentName);

		if (admin == null) {
		throw new SecurityException(String.format("No active admin for %s", componentName));
		}
		if (admin.getUid() != callerUid) {
		throw new SecurityException(
		String.format("Admin %s is not owned by uid %d", componentName, callerUid));
		}

		return new CallerIdentity(callerUid, componentName.getPackageName(), componentName);
		}

		/**
		* Checks if the device is in COMP mode, and if so migrates it to managed profile on a
		* corporate owned device.
		@@ -8728,6 +8761,14 @@ public class DevicePolicyManagerService extends BaseIDevicePolicyManager {
		}
		}

		private boolean isDeviceOwner(CallerIdentity identity) {
		synchronized (getLockObject()) {
		return mOwners.hasDeviceOwner()
		&& mOwners.getDeviceOwnerUserId() == identity.getUserId()
		&& mOwners.getDeviceOwnerComponent().equals(identity.getComponentName());
		}
		}

		private boolean isDeviceOwnerPackage(String packageName, int userId) {
		synchronized (getLockObject()) {
		return mOwners.hasDeviceOwner()
		@@ -11984,20 +12025,20 @@ public class DevicePolicyManagerService extends BaseIDevicePolicyManager {

		@Override
		public void setLocationEnabled(ComponentName who, boolean locationEnabled) {
		enforceDeviceOwner(Objects.requireNonNull(who));

		UserHandle user = mInjector.binderGetCallingUserHandle();
		CallerIdentity identity = getCallerIdentity(who);
		Preconditions.checkCallAuthorization(isDeviceOwner(identity));

		mInjector.binderWithCleanCallingIdentity(() -> {
		boolean wasLocationEnabled = mInjector.getLocationManager().isLocationEnabledForUser(
		user);
		mInjector.getLocationManager().setLocationEnabledForUser(locationEnabled, user);
		identity.getUserHandle());
		mInjector.getLocationManager().setLocationEnabledForUser(locationEnabled,
		identity.getUserHandle());

		// make a best effort to only show the notification if the admin is actually enabling
		// location. this is subject to race conditions with settings changes, but those are
		// unlikely to realistically interfere
		if (locationEnabled && (wasLocationEnabled != locationEnabled)) {
		showLocationSettingsEnabledNotification(user);
		if (locationEnabled && !wasLocationEnabled) {
		showLocationSettingsEnabledNotification(identity.getUserHandle());
		}
		});