1 /*
2  * Copyright (C) 2023 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.server.contentprotection;
18 
19 import android.annotation.NonNull;
20 import android.annotation.Nullable;
21 import android.content.pm.PackageInfo;
22 import android.util.Slog;
23 
24 import com.android.internal.annotations.VisibleForTesting;
25 
26 import java.io.BufferedReader;
27 import java.io.FileReader;
28 import java.util.Collections;
29 import java.util.List;
30 import java.util.Set;
31 import java.util.stream.Collectors;
32 
33 /**
34  * Manages whether the content protection is enabled for an app using a blocklist.
35  *
36  * @hide
37  */
38 public class ContentProtectionBlocklistManager {
39 
40     private static final String TAG = "ContentProtectionBlocklistManager";
41 
42     private static final String PACKAGE_NAME_BLOCKLIST_FILENAME =
43             "/product/etc/res/raw/content_protection/package_name_blocklist.txt";
44 
45     @NonNull private final ContentProtectionPackageManager mContentProtectionPackageManager;
46 
47     @Nullable private Set<String> mPackageNameBlocklist;
48 
ContentProtectionBlocklistManager( @onNull ContentProtectionPackageManager contentProtectionPackageManager)49     public ContentProtectionBlocklistManager(
50             @NonNull ContentProtectionPackageManager contentProtectionPackageManager) {
51         mContentProtectionPackageManager = contentProtectionPackageManager;
52     }
53 
isAllowed(@onNull String packageName)54     public boolean isAllowed(@NonNull String packageName) {
55         if (mPackageNameBlocklist == null) {
56             // List not loaded or failed to load, don't run on anything
57             return false;
58         }
59         if (mPackageNameBlocklist.contains(packageName)) {
60             return false;
61         }
62         PackageInfo packageInfo = mContentProtectionPackageManager.getPackageInfo(packageName);
63         if (packageInfo == null) {
64             return false;
65         }
66         if (!mContentProtectionPackageManager.hasRequestedInternetPermissions(packageInfo)) {
67             return false;
68         }
69         if (mContentProtectionPackageManager.isSystemApp(packageInfo)) {
70             return false;
71         }
72         if (mContentProtectionPackageManager.isUpdatedSystemApp(packageInfo)) {
73             return false;
74         }
75         return true;
76     }
77 
updateBlocklist(int blocklistSize)78     public void updateBlocklist(int blocklistSize) {
79         Slog.i(TAG, "Blocklist size updating to: " + blocklistSize);
80         mPackageNameBlocklist = readPackageNameBlocklist(blocklistSize);
81     }
82 
83     @Nullable
readPackageNameBlocklist(int blocklistSize)84     private Set<String> readPackageNameBlocklist(int blocklistSize) {
85         if (blocklistSize <= 0) {
86             // Explicitly requested an empty blocklist
87             return Collections.emptySet();
88         }
89         List<String> lines = readLinesFromRawFile(PACKAGE_NAME_BLOCKLIST_FILENAME);
90         if (lines == null) {
91             return null;
92         }
93         return lines.stream().limit(blocklistSize).collect(Collectors.toSet());
94     }
95 
96     @VisibleForTesting
97     @Nullable
readLinesFromRawFile(@onNull String filename)98     protected List<String> readLinesFromRawFile(@NonNull String filename) {
99         try (FileReader fileReader = new FileReader(filename);
100                 BufferedReader bufferedReader = new BufferedReader(fileReader)) {
101             return bufferedReader
102                     .lines()
103                     .map(line -> line.trim())
104                     .filter(line -> !line.isBlank())
105                     .collect(Collectors.toList());
106         } catch (Exception ex) {
107             Slog.e(TAG, "Failed to read: " + filename, ex);
108             return null;
109         }
110     }
111 }
112