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      1 /*
      2  * Copyright (C) 2015 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.statementservice.retriever;
     18 
     19 import android.content.Context;
     20 import android.content.pm.ApplicationInfo;
     21 import android.content.pm.PackageInfo;
     22 import android.content.pm.PackageManager;
     23 import android.content.pm.PackageManager.NameNotFoundException;
     24 import android.content.res.Resources.NotFoundException;
     25 
     26 import java.util.Arrays;
     27 import java.util.Collections;
     28 import java.util.List;
     29 
     30 /**
     31  * Class that provides information about an android app from {@link PackageManager}.
     32  *
     33  * Visible for testing.
     34  *
     35  * @hide
     36  */
     37 public class AndroidPackageInfoFetcher {
     38 
     39     /**
     40      * The name of the metadata tag in AndroidManifest.xml that stores the associated asset array
     41      * ID. The metadata tag should use the android:resource attribute to point to an array resource
     42      * that contains the associated assets.
     43      */
     44     private static final String ASSOCIATED_ASSETS_KEY = "associated_assets";
     45 
     46     private Context mContext;
     47 
     48     public AndroidPackageInfoFetcher(Context context) {
     49         mContext = context;
     50     }
     51 
     52     /**
     53      * Returns the Sha-256 fingerprints of all certificates from the specified package as a list of
     54      * upper case HEX Strings with bytes separated by colons. Given an app {@link
     55      * android.content.pm.Signature}, the fingerprint can be computed as {@link
     56      * Utils#computeNormalizedSha256Fingerprint} {@code(signature.toByteArray())}.
     57      *
     58      * <p>Given a signed APK, Java 7's commandline keytool can compute the fingerprint using: {@code
     59      * keytool -list -printcert -jarfile signed_app.apk}
     60      *
     61      * <p>Example: "10:39:38:EE:45:37:E5:9E:8E:E7:92:F6:54:50:4F:B8:34:6F:C6:B3:46:D0:BB:C4:41:5F:C3:39:FC:FC:8E:C1"
     62      *
     63      * @throws NameNotFoundException if an app with packageName is not installed on the device.
     64      */
     65     public List<String> getCertFingerprints(String packageName) throws NameNotFoundException {
     66         return Utils.getCertFingerprintsFromPackageManager(packageName, mContext);
     67     }
     68 
     69     /**
     70      * Returns all statements that the specified package makes in its AndroidManifest.xml.
     71      *
     72      * @throws NameNotFoundException if the app is not installed on the device.
     73      */
     74     public List<String> getStatements(String packageName) throws NameNotFoundException {
     75         PackageInfo packageInfo = mContext.getPackageManager().getPackageInfo(
     76                 packageName, PackageManager.GET_META_DATA);
     77         ApplicationInfo appInfo = packageInfo.applicationInfo;
     78         if (appInfo.metaData == null) {
     79             return Collections.<String>emptyList();
     80         }
     81         int tokenResourceId = appInfo.metaData.getInt(ASSOCIATED_ASSETS_KEY);
     82         if (tokenResourceId == 0) {
     83             return Collections.<String>emptyList();
     84         }
     85         try {
     86             return Arrays.asList(
     87                     mContext.getPackageManager().getResourcesForApplication(packageName)
     88                     .getStringArray(tokenResourceId));
     89         } catch (NotFoundException e) {
     90             return Collections.<String>emptyList();
     91         }
     92     }
     93 }
     94