Device config is not updated by background user for certain namespaces (c5377285) · Commits · e / os / android_frameworks_base

packages/SettingsProvider/src/com/android/providers/settings/NonWritableNamespacesForBackgroundUserPrefixes.java

0 → 100644

+39 −0

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2024 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.providers.settings;

		import android.util.ArraySet;

		import java.util.Arrays;
		import java.util.Set;

		/**
		* Contains the list of prefixes for namespaces in which nothing can be written by background
		* user.
		*
		* <p>
		* The list in enforced is Auto devices only. To add to
		* the list, create a change and tag the OWNER. In the change description, include a
		* description of the flag's functionality, and a justification for why it needs to be
		* denylisted.
		*/
		final class NonWritableNamespacesForBackgroundUserPrefixes {
		public static final Set<String> DENYLIST =
		new ArraySet<String>(Arrays.asList(
		"game_overlay"
		));
		}

packages/SettingsProvider/src/com/android/providers/settings/SettingsProvider.java

+42 −1

Original line number	Diff line number	Diff line
		@@ -2389,8 +2389,12 @@ public class SettingsProvider extends ContentProvider {
		== PackageManager.PERMISSION_GRANTED;
		boolean isRoot = Binder.getCallingUid() == Process.ROOT_UID;

		if (isRoot \|\| hasWritePermission) {
		if (isRoot) {
		return;
		}

		if (hasWritePermission) {
		assertCallingUserDenyList(flags);
		} else if (hasAllowlistPermission) {
		for (String flag : flags) {
		boolean namespaceAllowed = false;
		@@ -2407,12 +2411,49 @@ public class SettingsProvider extends ContentProvider {
		+ "'; allowlist permission granted, but must add flag to the allowlist.");
		}
		}
		assertCallingUserDenyList(flags);
		} else {
		throw new SecurityException("Permission denial to mutate flag, must have root, "
		+ "WRITE_DEVICE_CONFIG, or WRITE_ALLOWLISTED_DEVICE_CONFIG");
		}
		}

		// The check is added mainly for auto devices. On auto devices, it is possible that
		// multiple users are visible simultaneously using visible background users.
		// In such cases, it is desired that Non-current user (ex. visible background users) can
		// only change settings for certain namespaces.
		private void assertCallingUserDenyList(@NonNull Set<String> flags) {
		if (!UserManager.isVisibleBackgroundUsersEnabled()) {
		// enforce the deny list only on devices supporting visible background user.
		return;
		}

		int callingUser = UserHandle.getCallingUserId();
		final long identity = Binder.clearCallingIdentity();
		try {
		int currentUser = ActivityManager.getCurrentUser();
		if (callingUser == currentUser) {
		// enforce the deny list only if the caller is not current user. Currently only auto
		// uses background visible user, and auto doesn't support profiles so profiles of
		// current users is not checked here.
		return;
		}
		} finally {
		Binder.restoreCallingIdentity(identity);
		}

		for (String flag : flags) {
		for (String denylistedPrefix :
		NonWritableNamespacesForBackgroundUserPrefixes.DENYLIST) {
		if (flag.startsWith(denylistedPrefix)) {
		throw new SecurityException("Permission denial for flag '" + flag
		+ "' for background user " + callingUser + ". Namespace is added to "
		+ "denylist.");
		}
		}
		}
		}

		private static void warnOrThrowForUndesiredSecureSettingsMutationForTargetSdk(
		int targetSdkVersion, String name) {
		// If the app targets Lollipop MR1 or older SDK we warn, otherwise crash.