| /* |
| * Copyright (C) 2016 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.accounts; |
| |
| import android.accounts.Account; |
| import android.accounts.AccountManager; |
| import android.accounts.AccountManagerInternal; |
| import android.annotation.IntRange; |
| import android.annotation.NonNull; |
| import android.content.pm.PackageInfo; |
| import android.content.pm.PackageManager; |
| import android.content.pm.Signature; |
| import android.database.Cursor; |
| import android.database.sqlite.SQLiteDatabase; |
| import android.os.UserHandle; |
| import android.text.TextUtils; |
| import android.util.Log; |
| import android.util.PackageUtils; |
| import android.util.Pair; |
| import android.util.Slog; |
| import android.util.Xml; |
| import com.android.internal.annotations.GuardedBy; |
| import com.android.internal.content.PackageMonitor; |
| import com.android.internal.util.FastXmlSerializer; |
| import com.android.internal.util.XmlUtils; |
| import com.android.server.accounts.AccountsDb.DeDatabaseHelper; |
| |
| import org.xmlpull.v1.XmlPullParser; |
| import org.xmlpull.v1.XmlPullParserException; |
| import org.xmlpull.v1.XmlSerializer; |
| |
| import java.io.ByteArrayInputStream; |
| import java.io.ByteArrayOutputStream; |
| import java.io.IOException; |
| import java.nio.charset.StandardCharsets; |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| /** |
| * Helper class for backup and restore of account access grants. |
| */ |
| public final class AccountManagerBackupHelper { |
| private static final String TAG = "AccountManagerBackupHelper"; |
| |
| private static final long PENDING_RESTORE_TIMEOUT_MILLIS = 60 * 60 * 1000; // 1 hour |
| |
| private static final String TAG_PERMISSIONS = "permissions"; |
| private static final String TAG_PERMISSION = "permission"; |
| private static final String ATTR_ACCOUNT_SHA_256 = "account-sha-256"; |
| private static final String ATTR_PACKAGE = "package"; |
| private static final String ATTR_DIGEST = "digest"; |
| |
| private final Object mLock = new Object(); |
| |
| private final AccountManagerService mAccountManagerService; |
| private final AccountManagerInternal mAccountManagerInternal; |
| |
| @GuardedBy("mLock") |
| private List<PendingAppPermission> mRestorePendingAppPermissions; |
| |
| @GuardedBy("mLock") |
| private RestorePackageMonitor mRestorePackageMonitor; |
| |
| @GuardedBy("mLock") |
| private Runnable mRestoreCancelCommand; |
| |
| public AccountManagerBackupHelper(AccountManagerService accountManagerService, |
| AccountManagerInternal accountManagerInternal) { |
| mAccountManagerService = accountManagerService; |
| mAccountManagerInternal = accountManagerInternal; |
| } |
| |
| private final class PendingAppPermission { |
| private final @NonNull String accountDigest; |
| private final @NonNull String packageName; |
| private final @NonNull String certDigest; |
| private final @IntRange(from = 0) int userId; |
| |
| public PendingAppPermission(String accountDigest, String packageName, |
| String certDigest, int userId) { |
| this.accountDigest = accountDigest; |
| this.packageName = packageName; |
| this.certDigest = certDigest; |
| this.userId = userId; |
| } |
| |
| public boolean apply(PackageManager packageManager) { |
| Account account = null; |
| AccountManagerService.UserAccounts accounts = mAccountManagerService |
| .getUserAccounts(userId); |
| synchronized (accounts.dbLock) { |
| synchronized (accounts.cacheLock) { |
| for (Account[] accountsPerType : accounts.accountCache.values()) { |
| for (Account accountPerType : accountsPerType) { |
| if (accountDigest.equals(PackageUtils.computeSha256Digest( |
| accountPerType.name.getBytes()))) { |
| account = accountPerType; |
| break; |
| } |
| } |
| if (account != null) { |
| break; |
| } |
| } |
| } |
| } |
| if (account == null) { |
| return false; |
| } |
| final PackageInfo packageInfo; |
| try { |
| packageInfo = packageManager.getPackageInfoAsUser(packageName, |
| PackageManager.GET_SIGNATURES, userId); |
| } catch (PackageManager.NameNotFoundException e) { |
| return false; |
| } |
| |
| // Before we used only the first signature to compute the SHA 256 but some |
| // apps could be singed by multiple certs and the cert order is undefined. |
| // We prefer the modern computation procedure where all certs are taken |
| // into account but also allow the value from the old computation to allow |
| // restoring backed up grants on an older platform version. |
| final String[] signaturesSha256Digests = PackageUtils.computeSignaturesSha256Digests( |
| packageInfo.signatures); |
| final String signaturesSha256Digest = PackageUtils.computeSignaturesSha256Digest( |
| signaturesSha256Digests); |
| if (!certDigest.equals(signaturesSha256Digest) && (packageInfo.signatures.length <= 1 |
| || !certDigest.equals(signaturesSha256Digests[0]))) { |
| return false; |
| } |
| final int uid = packageInfo.applicationInfo.uid; |
| if (!mAccountManagerInternal.hasAccountAccess(account, uid)) { |
| mAccountManagerService.grantAppPermission(account, |
| AccountManager.ACCOUNT_ACCESS_TOKEN_TYPE, uid); |
| } |
| return true; |
| } |
| } |
| |
| public byte[] backupAccountAccessPermissions(int userId) { |
| final AccountManagerService.UserAccounts accounts = mAccountManagerService |
| .getUserAccounts(userId); |
| synchronized (accounts.dbLock) { |
| synchronized (accounts.cacheLock) { |
| List<Pair<String, Integer>> allAccountGrants = accounts.accountsDb |
| .findAllAccountGrants(); |
| if (allAccountGrants.isEmpty()) { |
| return null; |
| } |
| try { |
| ByteArrayOutputStream dataStream = new ByteArrayOutputStream(); |
| final XmlSerializer serializer = new FastXmlSerializer(); |
| serializer.setOutput(dataStream, StandardCharsets.UTF_8.name()); |
| serializer.startDocument(null, true); |
| serializer.startTag(null, TAG_PERMISSIONS); |
| |
| PackageManager packageManager = mAccountManagerService.mContext |
| .getPackageManager(); |
| for (Pair<String, Integer> grant : allAccountGrants) { |
| final String accountName = grant.first; |
| final int uid = grant.second; |
| |
| final String[] packageNames = packageManager.getPackagesForUid(uid); |
| if (packageNames == null) { |
| continue; |
| } |
| |
| for (String packageName : packageNames) { |
| final PackageInfo packageInfo; |
| try { |
| packageInfo = packageManager.getPackageInfoAsUser(packageName, |
| PackageManager.GET_SIGNATURES, userId); |
| } catch (PackageManager.NameNotFoundException e) { |
| Slog.i(TAG, "Skipping backup of account access grant for" |
| + " non-existing package: " + packageName); |
| continue; |
| } |
| final String digest = PackageUtils.computeSignaturesSha256Digest( |
| packageInfo.signatures); |
| if (digest != null) { |
| serializer.startTag(null, TAG_PERMISSION); |
| serializer.attribute(null, ATTR_ACCOUNT_SHA_256, |
| PackageUtils.computeSha256Digest(accountName.getBytes())); |
| serializer.attribute(null, ATTR_PACKAGE, packageName); |
| serializer.attribute(null, ATTR_DIGEST, digest); |
| serializer.endTag(null, TAG_PERMISSION); |
| } |
| } |
| } |
| serializer.endTag(null, TAG_PERMISSIONS); |
| serializer.endDocument(); |
| serializer.flush(); |
| return dataStream.toByteArray(); |
| } catch (IOException e) { |
| Log.e(TAG, "Error backing up account access grants", e); |
| return null; |
| } |
| } |
| } |
| } |
| |
| public void restoreAccountAccessPermissions(byte[] data, int userId) { |
| try { |
| ByteArrayInputStream dataStream = new ByteArrayInputStream(data); |
| XmlPullParser parser = Xml.newPullParser(); |
| parser.setInput(dataStream, StandardCharsets.UTF_8.name()); |
| PackageManager packageManager = mAccountManagerService.mContext.getPackageManager(); |
| |
| final int permissionsOuterDepth = parser.getDepth(); |
| while (XmlUtils.nextElementWithin(parser, permissionsOuterDepth)) { |
| if (!TAG_PERMISSIONS.equals(parser.getName())) { |
| continue; |
| } |
| final int permissionOuterDepth = parser.getDepth(); |
| while (XmlUtils.nextElementWithin(parser, permissionOuterDepth)) { |
| if (!TAG_PERMISSION.equals(parser.getName())) { |
| continue; |
| } |
| String accountDigest = parser.getAttributeValue(null, ATTR_ACCOUNT_SHA_256); |
| if (TextUtils.isEmpty(accountDigest)) { |
| XmlUtils.skipCurrentTag(parser); |
| } |
| String packageName = parser.getAttributeValue(null, ATTR_PACKAGE); |
| if (TextUtils.isEmpty(packageName)) { |
| XmlUtils.skipCurrentTag(parser); |
| } |
| String digest = parser.getAttributeValue(null, ATTR_DIGEST); |
| if (TextUtils.isEmpty(digest)) { |
| XmlUtils.skipCurrentTag(parser); |
| } |
| |
| PendingAppPermission pendingAppPermission = new PendingAppPermission( |
| accountDigest, packageName, digest, userId); |
| |
| if (!pendingAppPermission.apply(packageManager)) { |
| synchronized (mLock) { |
| // Start watching before add pending to avoid a missed signal |
| if (mRestorePackageMonitor == null) { |
| mRestorePackageMonitor = new RestorePackageMonitor(); |
| mRestorePackageMonitor.register(mAccountManagerService.mContext, |
| mAccountManagerService.mHandler.getLooper(), true); |
| } |
| if (mRestorePendingAppPermissions == null) { |
| mRestorePendingAppPermissions = new ArrayList<>(); |
| } |
| mRestorePendingAppPermissions.add(pendingAppPermission); |
| } |
| } |
| } |
| } |
| |
| // Make sure we eventually prune the in-memory pending restores |
| mRestoreCancelCommand = new CancelRestoreCommand(); |
| mAccountManagerService.mHandler.postDelayed(mRestoreCancelCommand, |
| PENDING_RESTORE_TIMEOUT_MILLIS); |
| } catch (XmlPullParserException | IOException e) { |
| Log.e(TAG, "Error restoring app permissions", e); |
| } |
| } |
| |
| private final class RestorePackageMonitor extends PackageMonitor { |
| @Override |
| public void onPackageAdded(String packageName, int uid) { |
| synchronized (mLock) { |
| if (mRestorePendingAppPermissions == null) { |
| return; |
| } |
| if (UserHandle.getUserId(uid) != UserHandle.USER_SYSTEM) { |
| return; |
| } |
| final int count = mRestorePendingAppPermissions.size(); |
| for (int i = count - 1; i >= 0; i--) { |
| PendingAppPermission pendingAppPermission = |
| mRestorePendingAppPermissions.get(i); |
| if (!pendingAppPermission.packageName.equals(packageName)) { |
| continue; |
| } |
| if (pendingAppPermission.apply( |
| mAccountManagerService.mContext.getPackageManager())) { |
| mRestorePendingAppPermissions.remove(i); |
| } |
| } |
| if (mRestorePendingAppPermissions.isEmpty() |
| && mRestoreCancelCommand != null) { |
| mAccountManagerService.mHandler.removeCallbacks(mRestoreCancelCommand); |
| mRestoreCancelCommand.run(); |
| mRestoreCancelCommand = null; |
| } |
| } |
| } |
| } |
| |
| private final class CancelRestoreCommand implements Runnable { |
| @Override |
| public void run() { |
| synchronized (mLock) { |
| mRestorePendingAppPermissions = null; |
| if (mRestorePackageMonitor != null) { |
| mRestorePackageMonitor.unregister(); |
| mRestorePackageMonitor = null; |
| } |
| } |
| } |
| } |
| } |