1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
|
/*
* 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.internal.telephony;
import android.app.AppOpsManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.os.Binder;
import android.provider.Telephony.Sms.Intents;
import android.telephony.SmsMessage;
import android.util.ArrayMap;
import android.util.Base64;
import android.util.Log;
import com.android.internal.annotations.GuardedBy;
import java.security.SecureRandom;
import java.util.Map;
/**
* Manager for app specific incoming SMS requests. This can be used to implement SMS based
* communication channels (e.g. for SMS based phone number verification) without needing the
* {@link Manifest.permission#RECEIVE_SMS} permission.
*
* {@link #createAppSpecificSmsRequest} allows an application to provide a {@link PendingIntent}
* that is triggered when an incoming SMS is received that contains the provided token.
*/
public class AppSmsManager {
private static final String LOG_TAG = "AppSmsManager";
private final SecureRandom mRandom;
private final Context mContext;
private final Object mLock = new Object();
@GuardedBy("mLock")
private final Map<String, AppRequestInfo> mTokenMap;
@GuardedBy("mLock")
private final Map<String, AppRequestInfo> mPackageMap;
public AppSmsManager(Context context) {
mRandom = new SecureRandom();
mTokenMap = new ArrayMap<>();
mPackageMap = new ArrayMap<>();
mContext = context;
}
/**
* Create an app specific incoming SMS request for the the calling package.
*
* This method returns a token that if included in a subsequent incoming SMS message the
* {@link Intents.SMS_RECEIVED_ACTION} intent will be delivered only to the calling package and
* will not require the application have the {@link Manifest.permission#RECEIVE_SMS} permission.
*
* An app can only have one request at a time, if the app already has a request it will be
* dropped and the new one will be added.
*
* @return Token to include in an SMS to have it delivered directly to the app.
*/
public String createAppSpecificSmsToken(String callingPkg, PendingIntent intent) {
// Check calling uid matches callingpkg.
AppOpsManager appOps = (AppOpsManager) mContext.getSystemService(Context.APP_OPS_SERVICE);
appOps.checkPackage(Binder.getCallingUid(), callingPkg);
// Generate a nonce to store the request under.
String token = generateNonce();
synchronized (mLock) {
// Only allow one request in flight from a package.
if (mPackageMap.containsKey(callingPkg)) {
removeRequestLocked(mPackageMap.get(callingPkg));
}
// Store state.
AppRequestInfo info = new AppRequestInfo(callingPkg, intent, token);
addRequestLocked(info);
}
return token;
}
/**
* Handle an incoming SMS_DELIVER_ACTION intent if it is an app-only SMS.
*/
public boolean handleSmsReceivedIntent(Intent intent) {
// Sanity check the action.
if (intent.getAction() != Intents.SMS_DELIVER_ACTION) {
Log.wtf(LOG_TAG, "Got intent with incorrect action: " + intent.getAction());
return false;
}
synchronized (mLock) {
AppRequestInfo info = findAppRequestInfoSmsIntentLocked(intent);
if (info == null) {
// The message didn't contain a token -- nothing to do.
return false;
}
try {
Intent fillIn = new Intent();
fillIn.putExtras(intent.getExtras());
info.pendingIntent.send(mContext, 0, fillIn);
} catch (PendingIntent.CanceledException e) {
// The pending intent is canceled, send this SMS as normal.
removeRequestLocked(info);
return false;
}
removeRequestLocked(info);
return true;
}
}
private AppRequestInfo findAppRequestInfoSmsIntentLocked(Intent intent) {
SmsMessage[] messages = Intents.getMessagesFromIntent(intent);
if (messages == null) {
return null;
}
StringBuilder fullMessageBuilder = new StringBuilder();
for (SmsMessage message : messages) {
if (message.getMessageBody() == null) {
continue;
}
fullMessageBuilder.append(message.getMessageBody());
}
String fullMessage = fullMessageBuilder.toString();
// Look for any tokens in the full message.
for (String token : mTokenMap.keySet()) {
if (fullMessage.contains(token)) {
return mTokenMap.get(token);
}
}
return null;
}
private String generateNonce() {
byte[] bytes = new byte[8];
mRandom.nextBytes(bytes);
return Base64.encodeToString(bytes, Base64.URL_SAFE | Base64.NO_WRAP | Base64.NO_PADDING);
}
private void removeRequestLocked(AppRequestInfo info) {
mTokenMap.remove(info.token);
mPackageMap.remove(info.packageName);
}
private void addRequestLocked(AppRequestInfo info) {
mTokenMap.put(info.token, info);
mPackageMap.put(info.packageName, info);
}
private final class AppRequestInfo {
public final String packageName;
public final PendingIntent pendingIntent;
public final String token;
AppRequestInfo(String packageName, PendingIntent pendingIntent, String token) {
this.packageName = packageName;
this.pendingIntent = pendingIntent;
this.token = token;
}
}
}
|
