1/*
2 * Copyright (C) 2012 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 an
14 * limitations under the License.
15 */
16
17package com.android.server.usb;
18
19import android.content.ActivityNotFoundException;
20import android.content.Context;
21import android.content.Intent;
22import android.net.LocalSocket;
23import android.net.LocalSocketAddress;
24import android.os.Handler;
25import android.os.HandlerThread;
26import android.os.Environment;
27import android.os.FileUtils;
28import android.os.Looper;
29import android.os.Message;
30import android.os.Process;
31import android.os.SystemClock;
32import android.util.Slog;
33import android.util.Base64;
34
35import java.lang.Thread;
36import java.io.File;
37import java.io.FileDescriptor;
38import java.io.FileOutputStream;
39import java.io.IOException;
40import java.io.InputStream;
41import java.io.OutputStream;
42import java.io.PrintWriter;
43import java.security.MessageDigest;
44import java.util.Arrays;
45
46public class UsbDebuggingManager implements Runnable {
47    private static final String TAG = "UsbDebuggingManager";
48    private static final boolean DEBUG = false;
49
50    private final String ADBD_SOCKET = "adbd";
51    private final String ADB_DIRECTORY = "misc/adb";
52    private final String ADB_KEYS_FILE = "adb_keys";
53    private final int BUFFER_SIZE = 4096;
54
55    private final Context mContext;
56    private final Handler mHandler;
57    private final HandlerThread mHandlerThread;
58    private Thread mThread;
59    private boolean mAdbEnabled = false;
60    private String mFingerprints;
61    private LocalSocket mSocket = null;
62    private OutputStream mOutputStream = null;
63
64    public UsbDebuggingManager(Context context) {
65        mHandlerThread = new HandlerThread("UsbDebuggingHandler");
66        mHandlerThread.start();
67        mHandler = new UsbDebuggingHandler(mHandlerThread.getLooper());
68        mContext = context;
69    }
70
71    private void listenToSocket() throws IOException {
72        try {
73            byte[] buffer = new byte[BUFFER_SIZE];
74            LocalSocketAddress address = new LocalSocketAddress(ADBD_SOCKET,
75                                         LocalSocketAddress.Namespace.RESERVED);
76            InputStream inputStream = null;
77
78            mSocket = new LocalSocket();
79            mSocket.connect(address);
80
81            mOutputStream = mSocket.getOutputStream();
82            inputStream = mSocket.getInputStream();
83
84            while (true) {
85                int count = inputStream.read(buffer);
86                if (count < 0) {
87                    Slog.e(TAG, "got " + count + " reading");
88                    break;
89                }
90
91                if (buffer[0] == 'P' && buffer[1] == 'K') {
92                    String key = new String(Arrays.copyOfRange(buffer, 2, count));
93                    Slog.d(TAG, "Received public key: " + key);
94                    Message msg = mHandler.obtainMessage(UsbDebuggingHandler.MESSAGE_ADB_CONFIRM);
95                    msg.obj = key;
96                    mHandler.sendMessage(msg);
97                }
98                else {
99                    Slog.e(TAG, "Wrong message: " + (new String(Arrays.copyOfRange(buffer, 0, 2))));
100                    break;
101                }
102            }
103        } catch (IOException ex) {
104            Slog.e(TAG, "Communication error: ", ex);
105            throw ex;
106        } finally {
107            closeSocket();
108        }
109    }
110
111    @Override
112    public void run() {
113        while (mAdbEnabled) {
114            try {
115                listenToSocket();
116            } catch (Exception e) {
117                /* Don't loop too fast if adbd dies, before init restarts it */
118                SystemClock.sleep(1000);
119            }
120        }
121    }
122
123    private void closeSocket() {
124        try {
125            mOutputStream.close();
126        } catch (IOException e) {
127            Slog.e(TAG, "Failed closing output stream: " + e);
128        }
129
130        try {
131            mSocket.close();
132        } catch (IOException ex) {
133            Slog.e(TAG, "Failed closing socket: " + ex);
134        }
135    }
136
137    private void sendResponse(String msg) {
138        if (mOutputStream != null) {
139            try {
140                mOutputStream.write(msg.getBytes());
141            }
142            catch (IOException ex) {
143                Slog.e(TAG, "Failed to write response:", ex);
144            }
145        }
146    }
147
148    class UsbDebuggingHandler extends Handler {
149        private static final int MESSAGE_ADB_ENABLED = 1;
150        private static final int MESSAGE_ADB_DISABLED = 2;
151        private static final int MESSAGE_ADB_ALLOW = 3;
152        private static final int MESSAGE_ADB_DENY = 4;
153        private static final int MESSAGE_ADB_CONFIRM = 5;
154        private static final int MESSAGE_ADB_CLEAR = 6;
155
156        public UsbDebuggingHandler(Looper looper) {
157            super(looper);
158        }
159
160        public void handleMessage(Message msg) {
161            switch (msg.what) {
162                case MESSAGE_ADB_ENABLED:
163                    if (mAdbEnabled)
164                        break;
165
166                    mAdbEnabled = true;
167
168                    mThread = new Thread(UsbDebuggingManager.this);
169                    mThread.start();
170
171                    break;
172
173                case MESSAGE_ADB_DISABLED:
174                    if (!mAdbEnabled)
175                        break;
176
177                    mAdbEnabled = false;
178                    closeSocket();
179
180                    try {
181                        mThread.join();
182                    } catch (Exception ex) {
183                    }
184
185                    mThread = null;
186                    mOutputStream = null;
187                    mSocket = null;
188                    break;
189
190                case MESSAGE_ADB_ALLOW: {
191                    String key = (String)msg.obj;
192                    String fingerprints = getFingerprints(key);
193
194                    if (!fingerprints.equals(mFingerprints)) {
195                        Slog.e(TAG, "Fingerprints do not match. Got "
196                                + fingerprints + ", expected " + mFingerprints);
197                        break;
198                    }
199
200                    if (msg.arg1 == 1) {
201                        writeKey(key);
202                    }
203
204                    sendResponse("OK");
205                    break;
206                }
207
208                case MESSAGE_ADB_DENY:
209                    sendResponse("NO");
210                    break;
211
212                case MESSAGE_ADB_CONFIRM: {
213                    String key = (String)msg.obj;
214                    mFingerprints = getFingerprints(key);
215                    showConfirmationDialog(key, mFingerprints);
216                    break;
217                }
218
219                case MESSAGE_ADB_CLEAR:
220                    deleteKeyFile();
221                    break;
222            }
223        }
224    }
225
226    private String getFingerprints(String key) {
227        String hex = "0123456789ABCDEF";
228        StringBuilder sb = new StringBuilder();
229        MessageDigest digester;
230
231        try {
232            digester = MessageDigest.getInstance("MD5");
233        } catch (Exception ex) {
234            Slog.e(TAG, "Error getting digester: " + ex);
235            return "";
236        }
237
238        byte[] base64_data = key.split("\\s+")[0].getBytes();
239        byte[] digest = digester.digest(Base64.decode(base64_data, Base64.DEFAULT));
240
241        for (int i = 0; i < digest.length; i++) {
242            sb.append(hex.charAt((digest[i] >> 4) & 0xf));
243            sb.append(hex.charAt(digest[i] & 0xf));
244            if (i < digest.length - 1)
245                sb.append(":");
246        }
247        return sb.toString();
248    }
249
250    private void showConfirmationDialog(String key, String fingerprints) {
251        Intent dialogIntent = new Intent();
252
253        dialogIntent.setClassName("com.android.systemui",
254                "com.android.systemui.usb.UsbDebuggingActivity");
255        dialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
256        dialogIntent.putExtra("key", key);
257        dialogIntent.putExtra("fingerprints", fingerprints);
258        try {
259            mContext.startActivity(dialogIntent);
260        } catch (ActivityNotFoundException e) {
261            Slog.e(TAG, "unable to start UsbDebuggingActivity");
262        }
263    }
264
265    private File getUserKeyFile() {
266        File dataDir = Environment.getDataDirectory();
267        File adbDir = new File(dataDir, ADB_DIRECTORY);
268
269        if (!adbDir.exists()) {
270            Slog.e(TAG, "ADB data directory does not exist");
271            return null;
272        }
273
274        return new File(adbDir, ADB_KEYS_FILE);
275    }
276
277    private void writeKey(String key) {
278        try {
279            File keyFile = getUserKeyFile();
280
281            if (keyFile == null) {
282                return;
283            }
284
285            if (!keyFile.exists()) {
286                keyFile.createNewFile();
287                FileUtils.setPermissions(keyFile.toString(),
288                    FileUtils.S_IRUSR | FileUtils.S_IWUSR |
289                    FileUtils.S_IRGRP, -1, -1);
290            }
291
292            FileOutputStream fo = new FileOutputStream(keyFile, true);
293            fo.write(key.getBytes());
294            fo.write('\n');
295            fo.close();
296        }
297        catch (IOException ex) {
298            Slog.e(TAG, "Error writing key:" + ex);
299        }
300    }
301
302    private void deleteKeyFile() {
303        File keyFile = getUserKeyFile();
304        if (keyFile != null) {
305            keyFile.delete();
306        }
307    }
308
309    public void setAdbEnabled(boolean enabled) {
310        mHandler.sendEmptyMessage(enabled ? UsbDebuggingHandler.MESSAGE_ADB_ENABLED
311                                          : UsbDebuggingHandler.MESSAGE_ADB_DISABLED);
312    }
313
314    public void allowUsbDebugging(boolean alwaysAllow, String publicKey) {
315        Message msg = mHandler.obtainMessage(UsbDebuggingHandler.MESSAGE_ADB_ALLOW);
316        msg.arg1 = alwaysAllow ? 1 : 0;
317        msg.obj = publicKey;
318        mHandler.sendMessage(msg);
319    }
320
321    public void denyUsbDebugging() {
322        mHandler.sendEmptyMessage(UsbDebuggingHandler.MESSAGE_ADB_DENY);
323    }
324
325    public void clearUsbDebuggingKeys() {
326        mHandler.sendEmptyMessage(UsbDebuggingHandler.MESSAGE_ADB_CLEAR);
327    }
328
329    public void dump(FileDescriptor fd, PrintWriter pw) {
330        pw.println("  USB Debugging State:");
331        pw.println("    Connected to adbd: " + (mOutputStream != null));
332        pw.println("    Last key received: " + mFingerprints);
333        pw.println("    User keys:");
334        try {
335            pw.println(FileUtils.readTextFile(new File("/data/misc/adb/adb_keys"), 0, null));
336        } catch (IOException e) {
337            pw.println("IOException: " + e);
338        }
339        pw.println("    System keys:");
340        try {
341            pw.println(FileUtils.readTextFile(new File("/adb_keys"), 0, null));
342        } catch (IOException e) {
343            pw.println("IOException: " + e);
344        }
345    }
346}
347