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/*
* Copyright (C) 2012 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.webkit;
import android.app.ActivityManagerNative;
import android.app.AppGlobals;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.ApplicationInfo;
import android.content.pm.IPackageDeleteObserver;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.Signature;
import android.content.pm.UserInfo;
import android.os.Binder;
import android.os.PatternMatcher;
import android.os.Process;
import android.os.RemoteException;
import android.os.ResultReceiver;
import android.os.UserHandle;
import android.os.UserManager;
import android.provider.Settings.Global;
import android.provider.Settings;
import android.util.AndroidRuntimeException;
import android.util.Slog;
import android.webkit.IWebViewUpdateService;
import android.webkit.WebViewFactory;
import android.webkit.WebViewProviderInfo;
import android.webkit.WebViewProviderResponse;
import com.android.server.SystemService;
import java.io.FileDescriptor;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
/**
* Private service to wait for the updatable WebView to be ready for use.
* @hide
*/
public class WebViewUpdateService extends SystemService {
private static final String TAG = "WebViewUpdateService";
private static final int WAIT_TIMEOUT_MS = 4500; // KEY_DISPATCHING_TIMEOUT is 5000.
// Keeps track of the number of running relro creations
private int mNumRelroCreationsStarted = 0;
private int mNumRelroCreationsFinished = 0;
// Implies that we need to rerun relro creation because we are using an out-of-date package
private boolean mWebViewPackageDirty = false;
private boolean mAnyWebViewInstalled = false;
private int NUMBER_OF_RELROS_UNKNOWN = Integer.MAX_VALUE;
// The WebView package currently in use (or the one we are preparing).
private PackageInfo mCurrentWebViewPackage = null;
// The WebView providers that are currently available.
private WebViewProviderInfo[] mCurrentValidWebViewPackages = null;
private BroadcastReceiver mWebViewUpdatedReceiver;
private WebViewUtilityInterface mWebViewUtility;
public WebViewUpdateService(Context context) {
super(context);
mWebViewUtility = new WebViewUtilityImpl();
}
@Override
public void onStart() {
mWebViewUpdatedReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
// When a package is replaced we will receive two intents, one representing
// the removal of the old package and one representing the addition of the
// new package.
// In the case where we receive an intent to remove the old version of the
// package that is being replaced we early-out here so that we don't run the
// update-logic twice.
if (intent.getAction().equals(Intent.ACTION_PACKAGE_REMOVED)
&& intent.getExtras().getBoolean(Intent.EXTRA_REPLACING)) {
return;
}
// Ensure that we only heed PACKAGE_CHANGED intents if they change an entire
// package, not just a component
if (intent.getAction().equals(Intent.ACTION_PACKAGE_CHANGED)) {
if (!WebViewFactory.entirePackageChanged(intent)) {
return;
}
}
if (intent.getAction().equals(Intent.ACTION_USER_ADDED)) {
int userId =
intent.getIntExtra(Intent.EXTRA_USER_HANDLE, UserHandle.USER_NULL);
handleNewUser(userId);
return;
}
updateFallbackState(context, intent);
for (WebViewProviderInfo provider : mWebViewUtility.getWebViewPackages()) {
String webviewPackage = "package:" + provider.packageName;
if (webviewPackage.equals(intent.getDataString())) {
boolean updateWebView = false;
boolean removedOrChangedOldPackage = false;
String oldProviderName = null;
PackageInfo newPackage = null;
synchronized(WebViewUpdateService.this) {
try {
updateValidWebViewPackages();
newPackage = findPreferredWebViewPackage();
if (mCurrentWebViewPackage != null)
oldProviderName = mCurrentWebViewPackage.packageName;
// Only trigger update actions if the updated package is the one
// that will be used, or the one that was in use before the
// update, or if we haven't seen a valid WebView package before.
updateWebView =
provider.packageName.equals(newPackage.packageName)
|| provider.packageName.equals(oldProviderName)
|| mCurrentWebViewPackage == null;
// We removed the old package if we received an intent to remove
// or replace the old package.
removedOrChangedOldPackage =
provider.packageName.equals(oldProviderName);
if (updateWebView) {
onWebViewProviderChanged(newPackage);
}
} catch (WebViewFactory.MissingWebViewPackageException e) {
Slog.e(TAG, "Could not find valid WebView package to create " +
"relro with " + e);
}
}
if(updateWebView && !removedOrChangedOldPackage
&& oldProviderName != null) {
// If the provider change is the result of adding or replacing a
// package that was not the previous provider then we must kill
// packages dependent on the old package ourselves. The framework
// only kills dependents of packages that are being removed.
mWebViewUtility.killPackageDependents(oldProviderName);
}
return;
}
}
}
};
IntentFilter filter = new IntentFilter();
filter.addAction(Intent.ACTION_PACKAGE_ADDED);
filter.addAction(Intent.ACTION_PACKAGE_REMOVED);
filter.addAction(Intent.ACTION_PACKAGE_CHANGED);
filter.addDataScheme("package");
// Make sure we only receive intents for WebView packages from our config file.
for (WebViewProviderInfo provider : mWebViewUtility.getWebViewPackages()) {
filter.addDataSchemeSpecificPart(provider.packageName, PatternMatcher.PATTERN_LITERAL);
}
getContext().registerReceiver(mWebViewUpdatedReceiver, filter);
IntentFilter userAddedFilter = new IntentFilter();
userAddedFilter.addAction(Intent.ACTION_USER_ADDED);
getContext().registerReceiver(mWebViewUpdatedReceiver, userAddedFilter);
publishBinderService("webviewupdate", new BinderService(), true /*allowIsolated*/);
}
private static boolean existsValidNonFallbackProvider(WebViewProviderInfo[] providers) {
for (WebViewProviderInfo provider : providers) {
if (provider.isAvailableByDefault() && provider.isEnabled()
&& provider.isValidProvider() && !provider.isFallbackPackage()) {
return true;
}
}
return false;
}
private static void enablePackageForUser(String packageName, boolean enable, int userId) {
try {
AppGlobals.getPackageManager().setApplicationEnabledSetting(
packageName,
enable ? PackageManager.COMPONENT_ENABLED_STATE_DEFAULT :
PackageManager.COMPONENT_ENABLED_STATE_DISABLED_USER, 0,
userId, null);
} catch (RemoteException e) {
Slog.w(TAG, "Tried to disable " + packageName + " for user " + userId + ": " + e);
}
}
/**
* Called when a new user has been added to update the state of its fallback package.
*/
void handleNewUser(int userId) {
if (!isFallbackLogicEnabled()) return;
WebViewProviderInfo[] webviewProviders = mWebViewUtility.getWebViewPackages();
WebViewProviderInfo fallbackProvider = getFallbackProvider(webviewProviders);
if (fallbackProvider == null) return;
boolean existsValidNonFallbackProvider =
existsValidNonFallbackProvider(webviewProviders);
enablePackageForUser(fallbackProvider.packageName, !existsValidNonFallbackProvider,
userId);
}
/**
* Handle the enabled-state of our fallback package, i.e. if there exists some non-fallback
* package that is valid (and available by default) then disable the fallback package,
* otherwise, enable the fallback package.
*/
void updateFallbackState(final Context context, final Intent intent) {
if (!isFallbackLogicEnabled()) return;
WebViewProviderInfo[] webviewProviders = mWebViewUtility.getWebViewPackages();
if (intent != null && (intent.getAction().equals(Intent.ACTION_PACKAGE_ADDED)
|| intent.getAction().equals(Intent.ACTION_PACKAGE_CHANGED))) {
// A package was changed / updated / downgraded, early out if it is not one of the
// webview packages that are available by default.
String changedPackage = null;
for (WebViewProviderInfo provider : webviewProviders) {
String webviewPackage = "package:" + provider.packageName;
if (webviewPackage.equals(intent.getDataString())) {
if (provider.isAvailableByDefault()) {
changedPackage = provider.packageName;
}
break;
}
}
if (changedPackage == null) return;
}
// If there exists a valid and enabled non-fallback package - disable the fallback
// package, otherwise, enable it.
WebViewProviderInfo fallbackProvider = getFallbackProvider(webviewProviders);
if (fallbackProvider == null) return;
boolean existsValidNonFallbackProvider = existsValidNonFallbackProvider(webviewProviders);
if (existsValidNonFallbackProvider
// During an OTA the primary user's WebView state might differ from other users', so
// ignore the state of that user during boot.
&& (fallbackProvider.isEnabled() || intent == null)) {
// Uninstall and disable fallback package for all users.
context.getPackageManager().deletePackage(fallbackProvider.packageName,
new IPackageDeleteObserver.Stub() {
public void packageDeleted(String packageName, int returnCode) {
// Ignore returnCode since the deletion could fail, e.g. we might be trying
// to delete a non-updated system-package (and we should still disable the
// package)
UserManager userManager =
(UserManager)context.getSystemService(Context.USER_SERVICE);
// Disable the fallback package for all users.
for(UserInfo userInfo : userManager.getUsers()) {
enablePackageForUser(packageName, false, userInfo.id);
}
}
}, PackageManager.DELETE_SYSTEM_APP | PackageManager.DELETE_ALL_USERS);
} else if (!existsValidNonFallbackProvider
// During an OTA the primary user's WebView state might differ from other users', so
// ignore the state of that user during boot.
&& (!fallbackProvider.isEnabled() || intent==null)) {
// Enable the fallback package for all users.
UserManager userManager =
(UserManager)context.getSystemService(Context.USER_SERVICE);
for(UserInfo userInfo : userManager.getUsers()) {
enablePackageForUser(fallbackProvider.packageName, true, userInfo.id);
}
}
}
private static boolean isFallbackLogicEnabled() {
// Note that this is enabled by default (i.e. if the setting hasn't been set).
return Settings.Global.getInt(AppGlobals.getInitialApplication().getContentResolver(),
Settings.Global.WEBVIEW_FALLBACK_LOGIC_ENABLED, 1) == 1;
}
private static void enableFallbackLogic(boolean enable) {
Settings.Global.putInt(AppGlobals.getInitialApplication().getContentResolver(),
Settings.Global.WEBVIEW_FALLBACK_LOGIC_ENABLED, enable ? 1 : 0);
}
/**
* Returns the only fallback provider, or null if there is none.
*/
private static WebViewProviderInfo getFallbackProvider(WebViewProviderInfo[] webviewPackages) {
for (WebViewProviderInfo provider : webviewPackages) {
if (provider.isFallbackPackage()) {
return provider;
}
}
return null;
}
private static boolean containsAvailableNonFallbackProvider(
WebViewProviderInfo[] webviewPackages) {
for (WebViewProviderInfo provider : webviewPackages) {
if (provider.isAvailableByDefault() && provider.isEnabled()
&& provider.isValidProvider() && !provider.isFallbackPackage()) {
return true;
}
}
return false;
}
private boolean isFallbackPackage(String packageName) {
if (packageName == null || !isFallbackLogicEnabled()) return false;
WebViewProviderInfo[] webviewPackages = mWebViewUtility.getWebViewPackages();
WebViewProviderInfo fallbackProvider = getFallbackProvider(webviewPackages);
return (fallbackProvider != null
&& packageName.equals(fallbackProvider.packageName));
}
/**
* Perform any WebView loading preparations that must happen at boot from the system server,
* after the package manager has started or after an update to the webview is installed.
* This must be called in the system server.
* Currently, this means spawning the child processes which will create the relro files.
*/
public void prepareWebViewInSystemServer() {
updateFallbackState(getContext(), null);
try {
synchronized(this) {
updateValidWebViewPackages();
mCurrentWebViewPackage = findPreferredWebViewPackage();
onWebViewProviderChanged(mCurrentWebViewPackage);
}
} catch (Throwable t) {
// Log and discard errors at this stage as we must not crash the system server.
Slog.e(TAG, "error preparing webview provider from system server", t);
}
}
/**
* Change WebView provider and provider setting and kill packages using the old provider.
* Return the new provider (in case we are in the middle of creating relro files this new
* provider will not be in use directly, but will when the relros are done).
*/
private String changeProviderAndSetting(String newProviderName) {
PackageInfo oldPackage = null;
PackageInfo newPackage = null;
synchronized(this) {
oldPackage = mCurrentWebViewPackage;
mWebViewUtility.updateUserSetting(getContext(), newProviderName);
try {
newPackage = findPreferredWebViewPackage();
if (oldPackage != null && newPackage.packageName.equals(oldPackage.packageName)) {
// If we don't perform the user change, revert the settings change.
mWebViewUtility.updateUserSetting(getContext(), newPackage.packageName);
return newPackage.packageName;
}
} catch (WebViewFactory.MissingWebViewPackageException e) {
Slog.e(TAG, "Tried to change WebView provider but failed to fetch WebView package "
+ e);
// If we don't perform the user change but don't have an installed WebView package,
// we will have changed the setting and it will be used when a package is available.
return newProviderName;
}
onWebViewProviderChanged(newPackage);
}
// Kill apps using the old provider
if (oldPackage != null) {
mWebViewUtility.killPackageDependents(oldPackage.packageName);
}
return newPackage.packageName;
}
/**
* This is called when we change WebView provider, either when the current provider is updated
* or a new provider is chosen / takes precedence.
*/
private void onWebViewProviderChanged(PackageInfo newPackage) {
synchronized(this) {
mAnyWebViewInstalled = true;
if (mNumRelroCreationsStarted == mNumRelroCreationsFinished) {
mCurrentWebViewPackage = newPackage;
mWebViewUtility.updateUserSetting(getContext(), newPackage.packageName);
// The relro creations might 'finish' (not start at all) before
// WebViewFactory.onWebViewProviderChanged which means we might not know the number
// of started creations before they finish.
mNumRelroCreationsStarted = NUMBER_OF_RELROS_UNKNOWN;
mNumRelroCreationsFinished = 0;
mNumRelroCreationsStarted = mWebViewUtility.onWebViewProviderChanged(newPackage);
// If the relro creations finish before we know the number of started creations we
// will have to do any cleanup/notifying here.
checkIfRelrosDoneLocked();
} else {
mWebViewPackageDirty = true;
}
}
}
/**
* Updates the currently valid WebView provider packages.
* Should be used when a provider has been installed or removed.
* @hide
* */
private void updateValidWebViewPackages() {
List<WebViewProviderInfo> webViewProviders =
new ArrayList<WebViewProviderInfo>(Arrays.asList(mWebViewUtility.getWebViewPackages()));
Iterator<WebViewProviderInfo> it = webViewProviders.iterator();
// remove non-valid packages
while(it.hasNext()) {
WebViewProviderInfo current = it.next();
if (!current.isValidProvider())
it.remove();
}
synchronized(this) {
mCurrentValidWebViewPackages =
webViewProviders.toArray(new WebViewProviderInfo[webViewProviders.size()]);
}
}
/**
* Returns either the package info of the WebView provider determined in the following way:
* If the user has chosen a provider then use that if it is valid,
* otherwise use the first package in the webview priority list that is valid.
*
* @hide
*/
private PackageInfo findPreferredWebViewPackage() {
WebViewProviderInfo[] providers = mCurrentValidWebViewPackages;
String userChosenProvider = mWebViewUtility.getUserChosenWebViewProvider(getContext());
// If the user has chosen provider, use that
for (WebViewProviderInfo provider : providers) {
if (provider.packageName.equals(userChosenProvider) && provider.isEnabled()) {
return provider.getPackageInfo();
}
}
// User did not choose, or the choice failed; use the most stable provider that is
// enabled and available by default (not through user choice).
for (WebViewProviderInfo provider : providers) {
if (provider.isAvailableByDefault() && provider.isEnabled()) {
return provider.getPackageInfo();
}
}
// Could not find any enabled package either, use the most stable provider.
for (WebViewProviderInfo provider : providers) {
return provider.getPackageInfo();
}
mAnyWebViewInstalled = false;
throw new WebViewFactory.MissingWebViewPackageException(
"Could not find a loadable WebView package");
}
/**
* Returns whether WebView is ready and is not going to go through its preparation phase again
* directly.
*/
private boolean webViewIsReadyLocked() {
return !mWebViewPackageDirty
&& (mNumRelroCreationsStarted == mNumRelroCreationsFinished)
// The current package might be replaced though we haven't received an intent declaring
// this yet, the following flag makes anyone loading WebView to wait in this case.
&& mAnyWebViewInstalled;
}
private void checkIfRelrosDoneLocked() {
if (mNumRelroCreationsStarted == mNumRelroCreationsFinished) {
if (mWebViewPackageDirty) {
mWebViewPackageDirty = false;
// If we have changed provider since we started the relro creation we need to
// redo the whole process using the new package instead.
PackageInfo newPackage = findPreferredWebViewPackage();
onWebViewProviderChanged(newPackage);
} else {
this.notifyAll();
}
}
}
private class BinderService extends IWebViewUpdateService.Stub {
@Override
public void onShellCommand(FileDescriptor in, FileDescriptor out,
FileDescriptor err, String[] args, ResultReceiver resultReceiver) {
(new WebViewUpdateServiceShellCommand(this)).exec(
this, in, out, err, args, resultReceiver);
}
/**
* The shared relro process calls this to notify us that it's done trying to create a relro
* file. This method gets called even if the relro creation has failed or the process
* crashed.
*/
@Override // Binder call
public void notifyRelroCreationCompleted() {
// Verify that the caller is either the shared relro process (nominal case) or the
// system server (only in the case the relro process crashes and we get here via the
// crashHandler).
if (Binder.getCallingUid() != Process.SHARED_RELRO_UID &&
Binder.getCallingUid() != Process.SYSTEM_UID) {
return;
}
long callingId = Binder.clearCallingIdentity();
try {
synchronized (WebViewUpdateService.this) {
mNumRelroCreationsFinished++;
checkIfRelrosDoneLocked();
}
} finally {
Binder.restoreCallingIdentity(callingId);
}
}
/**
* WebViewFactory calls this to block WebView loading until the relro file is created.
* Returns the WebView provider for which we create relro files.
*/
@Override // Binder call
public WebViewProviderResponse waitForAndGetProvider() {
// The WebViewUpdateService depends on the prepareWebViewInSystemServer call, which
// happens later (during the PHASE_ACTIVITY_MANAGER_READY) in SystemServer.java. If
// another service there tries to bring up a WebView in the between, the wait below
// would deadlock without the check below.
if (Binder.getCallingPid() == Process.myPid()) {
throw new IllegalStateException("Cannot create a WebView from the SystemServer");
}
PackageInfo webViewPackage = null;
final long NS_PER_MS = 1000000;
final long timeoutTimeMs = System.nanoTime() / NS_PER_MS + WAIT_TIMEOUT_MS;
boolean webViewReady = false;
int webViewStatus = WebViewFactory.LIBLOAD_SUCCESS;
synchronized (WebViewUpdateService.this) {
webViewReady = WebViewUpdateService.this.webViewIsReadyLocked();
while (!webViewReady) {
final long timeNowMs = System.nanoTime() / NS_PER_MS;
if (timeNowMs >= timeoutTimeMs) break;
try {
WebViewUpdateService.this.wait(timeoutTimeMs - timeNowMs);
} catch (InterruptedException e) {}
webViewReady = WebViewUpdateService.this.webViewIsReadyLocked();
}
// Make sure we return the provider that was used to create the relro file
webViewPackage = WebViewUpdateService.this.mCurrentWebViewPackage;
if (webViewReady) {
} else if (!mAnyWebViewInstalled) {
webViewStatus = WebViewFactory.LIBLOAD_FAILED_LISTING_WEBVIEW_PACKAGES;
} else {
// Either the current relro creation isn't done yet, or the new relro creatioin
// hasn't kicked off yet (the last relro creation used an out-of-date WebView).
webViewStatus = WebViewFactory.LIBLOAD_FAILED_WAITING_FOR_RELRO;
}
}
if (!webViewReady) Slog.w(TAG, "creating relro file timed out");
return new WebViewProviderResponse(webViewPackage, webViewStatus);
}
/**
* This is called from DeveloperSettings when the user changes WebView provider.
*/
@Override // Binder call
public String changeProviderAndSetting(String newProvider) {
if (getContext().checkCallingPermission(
android.Manifest.permission.WRITE_SECURE_SETTINGS)
!= PackageManager.PERMISSION_GRANTED) {
String msg = "Permission Denial: changeProviderAndSetting() from pid="
+ Binder.getCallingPid()
+ ", uid=" + Binder.getCallingUid()
+ " requires " + android.Manifest.permission.WRITE_SECURE_SETTINGS;
Slog.w(TAG, msg);
throw new SecurityException(msg);
}
return WebViewUpdateService.this.changeProviderAndSetting(newProvider);
}
@Override // Binder call
public WebViewProviderInfo[] getValidWebViewPackages() {
synchronized(WebViewUpdateService.this) {
return mCurrentValidWebViewPackages;
}
}
@Override // Binder call
public WebViewProviderInfo[] getAllWebViewPackages() {
return WebViewUpdateService.this.mWebViewUtility.getWebViewPackages();
}
@Override // Binder call
public String getCurrentWebViewPackageName() {
synchronized(WebViewUpdateService.this) {
if (WebViewUpdateService.this.mCurrentWebViewPackage == null)
return null;
return WebViewUpdateService.this.mCurrentWebViewPackage.packageName;
}
}
@Override // Binder call
public boolean isFallbackPackage(String packageName) {
return WebViewUpdateService.this.isFallbackPackage(packageName);
}
@Override // Binder call
public void enableFallbackLogic(boolean enable) {
if (getContext().checkCallingPermission(
android.Manifest.permission.WRITE_SECURE_SETTINGS)
!= PackageManager.PERMISSION_GRANTED) {
String msg = "Permission Denial: enableFallbackLogic() from pid="
+ Binder.getCallingPid()
+ ", uid=" + Binder.getCallingUid()
+ " requires " + android.Manifest.permission.WRITE_SECURE_SETTINGS;
Slog.w(TAG, msg);
throw new SecurityException(msg);
}
WebViewUpdateService.enableFallbackLogic(enable);
}
}
}