1 /* 2 * Copyright (C) 2014 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 package com.android.nfc; 17 18 19 import android.content.Context; 20 import android.content.Intent; 21 import android.net.wifi.WifiConfiguration; 22 import android.nfc.NdefMessage; 23 import android.nfc.NdefRecord; 24 import android.nfc.tech.Ndef; 25 import android.os.UserHandle; 26 import android.os.UserManager; 27 import android.util.Log; 28 29 import java.nio.BufferUnderflowException; 30 import java.nio.ByteBuffer; 31 import java.util.Arrays; 32 import java.util.BitSet; 33 34 public final class NfcWifiProtectedSetup { 35 36 public static final String NFC_TOKEN_MIME_TYPE = "application/vnd.wfa.wsc"; 37 38 public static final String EXTRA_WIFI_CONFIG = "com.android.nfc.WIFI_CONFIG_EXTRA"; 39 40 /* 41 * ID into configuration record for SSID and Network Key in hex. 42 * Obtained from WFA Wifi Simple Configuration Technical Specification v2.0.2.1. 43 */ 44 private static final short CREDENTIAL_FIELD_ID = 0x100E; 45 private static final short SSID_FIELD_ID = 0x1045; 46 private static final short NETWORK_KEY_FIELD_ID = 0x1027; 47 private static final short AUTH_TYPE_FIELD_ID = 0x1003; 48 49 private static final short AUTH_TYPE_EXPECTED_SIZE = 2; 50 51 private static final short AUTH_TYPE_OPEN = 0; 52 private static final short AUTH_TYPE_WPA_PSK = 0x0002; 53 private static final short AUTH_TYPE_WPA_EAP = 0x0008; 54 private static final short AUTH_TYPE_WPA2_EAP = 0x0010; 55 private static final short AUTH_TYPE_WPA2_PSK = 0x0020; 56 57 private static final int MAX_NETWORK_KEY_SIZE_BYTES = 64; 58 NfcWifiProtectedSetup()59 private NfcWifiProtectedSetup() {} 60 tryNfcWifiSetup(Ndef ndef, Context context)61 public static boolean tryNfcWifiSetup(Ndef ndef, Context context) { 62 63 if (ndef == null || context == null) { 64 return false; 65 } 66 67 NdefMessage cachedNdefMessage = ndef.getCachedNdefMessage(); 68 if (cachedNdefMessage == null) { 69 return false; 70 } 71 72 final WifiConfiguration wifiConfiguration; 73 try { 74 wifiConfiguration = parse(cachedNdefMessage); 75 } catch (BufferUnderflowException e) { 76 // malformed payload 77 return false; 78 } 79 80 if (wifiConfiguration != null &&!UserManager.get(context).hasUserRestriction( 81 UserManager.DISALLOW_CONFIG_WIFI, UserHandle.CURRENT)) { 82 Intent configureNetworkIntent = new Intent() 83 .putExtra(EXTRA_WIFI_CONFIG, wifiConfiguration) 84 .setClass(context, ConfirmConnectToWifiNetworkActivity.class) 85 .setFlags(Intent.FLAG_ACTIVITY_NEW_TASK); 86 87 context.startActivityAsUser(configureNetworkIntent, UserHandle.CURRENT); 88 return true; 89 } 90 91 return false; 92 } 93 parse(NdefMessage message)94 private static WifiConfiguration parse(NdefMessage message) { 95 NdefRecord[] records = message.getRecords(); 96 97 for (NdefRecord record : records) { 98 if (new String(record.getType()).equals(NFC_TOKEN_MIME_TYPE)) { 99 ByteBuffer payload = ByteBuffer.wrap(record.getPayload()); 100 while (payload.hasRemaining()) { 101 short fieldId = payload.getShort(); 102 short fieldSize = payload.getShort(); 103 if (fieldId == CREDENTIAL_FIELD_ID) { 104 return parseCredential(payload, fieldSize); 105 } 106 } 107 } 108 } 109 return null; 110 } 111 parseCredential(ByteBuffer payload, short size)112 private static WifiConfiguration parseCredential(ByteBuffer payload, short size) { 113 int startPosition = payload.position(); 114 WifiConfiguration result = new WifiConfiguration(); 115 while (payload.position() < startPosition + size) { 116 short fieldId = payload.getShort(); 117 short fieldSize = payload.getShort(); 118 119 // sanity check 120 if (payload.position() + fieldSize > startPosition + size) { 121 return null; 122 } 123 124 switch (fieldId) { 125 case SSID_FIELD_ID: 126 byte[] ssid = new byte[fieldSize]; 127 payload.get(ssid); 128 result.SSID = "\"" + new String(ssid) + "\""; 129 break; 130 case NETWORK_KEY_FIELD_ID: 131 if (fieldSize > MAX_NETWORK_KEY_SIZE_BYTES) { 132 return null; 133 } 134 byte[] networkKey = new byte[fieldSize]; 135 payload.get(networkKey); 136 result.preSharedKey = "\"" + new String(networkKey) + "\""; 137 break; 138 case AUTH_TYPE_FIELD_ID: 139 if (fieldSize != AUTH_TYPE_EXPECTED_SIZE) { 140 // corrupt data 141 return null; 142 } 143 144 short authType = payload.getShort(); 145 populateAllowedKeyManagement(result.allowedKeyManagement, authType); 146 break; 147 default: 148 // unknown / unparsed tag 149 payload.position(payload.position() + fieldSize); 150 break; 151 } 152 } 153 154 if (result.preSharedKey != null && result.SSID != null) { 155 return result; 156 } 157 158 return null; 159 } 160 populateAllowedKeyManagement(BitSet allowedKeyManagement, short authType)161 private static void populateAllowedKeyManagement(BitSet allowedKeyManagement, short authType) { 162 if (authType == AUTH_TYPE_WPA_PSK || authType == AUTH_TYPE_WPA2_PSK) { 163 allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_PSK); 164 } else if (authType == AUTH_TYPE_WPA_EAP || authType == AUTH_TYPE_WPA2_EAP) { 165 allowedKeyManagement.set(WifiConfiguration.KeyMgmt.WPA_EAP); 166 } else if (authType == AUTH_TYPE_OPEN) { 167 allowedKeyManagement.set(WifiConfiguration.KeyMgmt.NONE); 168 } 169 } 170 } 171