Pileus Git - ~andy/freeotp/blob - src/org/fedorahosted/freeotp/Token.java

   1 /*
   2  * FreeOTP
   3  *
   4  * Authors: Nathaniel McCallum <npmccallum@redhat.com>
   5  *
   6  * Copyright (C) 2013  Nathaniel McCallum, Red Hat
   7  *
   8  * Licensed under the Apache License, Version 2.0 (the "License");
   9  * you may not use this file except in compliance with the License.
  10  * You may obtain a copy of the License at
  11  *
  12  *     http://www.apache.org/licenses/LICENSE-2.0
  13  *
  14  * Unless required by applicable law or agreed to in writing, software
  15  * distributed under the License is distributed on an "AS IS" BASIS,
  16  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  17  * See the License for the specific language governing permissions and
  18  * limitations under the License.
  19  */
  20
  21 package org.fedorahosted.freeotp;
  22
  23 import java.nio.ByteBuffer;
  24 import java.security.InvalidKeyException;
  25 import java.security.NoSuchAlgorithmException;
  26 import java.util.Locale;
  27
  28 import javax.crypto.Mac;
  29 import javax.crypto.spec.SecretKeySpec;
  30
  31 import android.net.Uri;
  32
  33 import com.google.android.apps.authenticator.Base32String;
  34 import com.google.android.apps.authenticator.Base32String.DecodingException;
  35
  36 public class Token {
  37         public static class TokenUriInvalidException extends Exception {
  38                 private static final long serialVersionUID = -1108624734612362345L;
  39         }
  40
  41         public static enum TokenType {
  42                 HOTP, TOTP
  43         }
  44
  45         private final String mIssuerInt;
  46         private final String mIssuerExt;
  47         private final String mLabel;
  48         private TokenType mType;
  49         private String mAlgorithm;
  50         private byte[] mSecret;
  51         private int mDigits;
  52         private long mCounter;
  53         private int mPeriod;
  54         private long mLastCode;
  55
  56         private Token(Uri uri) throws TokenUriInvalidException {
  57                 if (!uri.getScheme().equals("otpauth"))
  58                         throw new TokenUriInvalidException();
  59
  60                 if (uri.getAuthority().equals("totp"))
  61                         mType = TokenType.TOTP;
  62                 else if (uri.getAuthority().equals("hotp"))
  63                         mType = TokenType.HOTP;
  64                 else
  65                         throw new TokenUriInvalidException();
  66
  67                 String path = uri.getPath();
  68                 if (path == null)
  69                         throw new TokenUriInvalidException();
  70
  71                 // Strip the path of its leading '/'
  72                 for (int i = 0; path.charAt(i) == '/'; i++)
  73                         path = path.substring(1);
  74                 if (path.length() == 0)
  75                         throw new TokenUriInvalidException();
  76
  77                 int i = path.indexOf(':');
  78                 mIssuerExt = i < 0 ? "" : path.substring(0, i);
  79                 mIssuerInt = uri.getQueryParameter("issuer");
  80                 mLabel = path.substring(i >= 0 ? i + 1 : 0);
  81
  82                 mAlgorithm = uri.getQueryParameter("algorithm");
  83                 if (mAlgorithm == null)
  84                         mAlgorithm = "sha1";
  85                 mAlgorithm = mAlgorithm.toUpperCase(Locale.US);
  86                 try {
  87                         Mac.getInstance("Hmac" + mAlgorithm);
  88                 } catch (NoSuchAlgorithmException e1) {
  89                         throw new TokenUriInvalidException();
  90                 }
  91
  92                 try {
  93                         String d = uri.getQueryParameter("digits");
  94                         if (d == null)
  95                                 d = "6";
  96                         mDigits = Integer.parseInt(d);
  97                         if (mDigits != 6 && mDigits != 8)
  98                                 throw new TokenUriInvalidException();
  99                 } catch (NumberFormatException e) {
 100                         throw new TokenUriInvalidException();
 101                 }
 102
 103                 switch (mType) {
 104                 case HOTP:
 105                         try {
 106                                 String c = uri.getQueryParameter("counter");
 107                                 if (c == null)
 108                                         c = "0";
 109                                 mCounter = Long.parseLong(c) - 1;
 110                         } catch (NumberFormatException e) {
 111                                 throw new TokenUriInvalidException();
 112                         }
 113                         break;
 114                 case TOTP:
 115                         try {
 116                                 String p = uri.getQueryParameter("period");
 117                                 if (p == null)
 118                                         p = "30";
 119                                 mPeriod = Integer.parseInt(p);
 120                         } catch (NumberFormatException e) {
 121                                 throw new TokenUriInvalidException();
 122                         }
 123                         break;
 124                 }
 125
 126                 try {
 127                         String s = uri.getQueryParameter("secret");
 128                         mSecret = Base32String.decode(s);
 129                 } catch (DecodingException e) {
 130                         throw new TokenUriInvalidException();
 131                 }
 132         }
 133
 134         private String getHOTP(long counter) {
 135                 // Encode counter in network byte order
 136                 ByteBuffer bb = ByteBuffer.allocate(8);
 137                 bb.putLong(counter);
 138
 139                 // Create digits divisor
 140                 int div = 1;
 141                 for (int i = mDigits; i > 0; i--)
 142                         div *= 10;
 143
 144                 // Create the HMAC
 145                 try {
 146                         Mac mac = Mac.getInstance("Hmac" + mAlgorithm);
 147                         mac.init(new SecretKeySpec(mSecret, "Hmac" + mAlgorithm));
 148
 149                         // Do the hashing
 150                         byte[] digest = mac.doFinal(bb.array());
 151
 152                         // Truncate
 153                         int binary;
 154                         int off = digest[digest.length - 1] & 0xf;
 155                         binary  = (digest[off + 0] & 0x7f) << 0x18;
 156                         binary |= (digest[off + 1] & 0xff) << 0x10;
 157                         binary |= (digest[off + 2] & 0xff) << 0x08;
 158                         binary |= (digest[off + 3] & 0xff) << 0x00;
 159                         binary  = binary % div;
 160
 161                         // Zero pad
 162                         String hotp = Integer.toString(binary);
 163                         while (hotp.length() != mDigits)
 164                                 hotp = "0" + hotp;
 165
 166                         return hotp;
 167                 } catch (InvalidKeyException e) {
 168                         e.printStackTrace();
 169                 } catch (NoSuchAlgorithmException e) {
 170                         e.printStackTrace();
 171                 }
 172
 173                 return "";
 174         }
 175
 176         public Token(String uri) throws TokenUriInvalidException {
 177                 this(Uri.parse(uri));
 178         }
 179
 180         public void increment() {
 181                 if (mType == TokenType.HOTP) {
 182                         mCounter++;
 183                         mLastCode = System.currentTimeMillis();
 184                 }
 185         }
 186
 187         public String getID() {
 188                 String id;
 189                 if (mIssuerInt != null && !mIssuerInt.equals(""))
 190                         id = mIssuerInt + ":" + mLabel;
 191                 else if (mIssuerExt != null && !mIssuerExt.equals(""))
 192                         id = mIssuerExt + ":" + mLabel;
 193                 else
 194                         id = mLabel;
 195
 196                 return id;
 197         }
 198
 199         public String getIssuer() {
 200                 return mIssuerExt != null ? mIssuerExt : "";
 201         }
 202
 203         public String getLabel() {
 204                 return mLabel != null ? mLabel : "";
 205         }
 206
 207         public String getCode() {
 208                 if (mType == TokenType.TOTP)
 209                         return getHOTP(System.currentTimeMillis() / 1000 / mPeriod);
 210
 211                 long time = System.currentTimeMillis();
 212                 if (time - mLastCode > 60000) {
 213                         StringBuilder sb = new StringBuilder(mDigits);
 214                         for (int i = 0; i < mDigits; i++)
 215                                 sb.append('-');
 216                         return sb.toString();
 217                 }
 218
 219                 return getHOTP(mCounter);
 220         }
 221
 222         public TokenType getType() {
 223                 return mType;
 224         }
 225
 226         // Progress is on a scale from 0 - 1000.
 227         public int getProgress() {
 228                 long time = System.currentTimeMillis();
 229
 230                 if (mType == TokenType.TOTP)
 231                         return (int) (time % (mPeriod * 1000) / mPeriod);
 232
 233                 long state = (time - mLastCode) / 60;
 234                 return (int) (state > 1000 ? 1000 : state);
 235         }
 236
 237         public Uri toUri() {
 238                 String issuerLabel = !mIssuerExt.equals("") ? mIssuerExt + ":" + mLabel : mLabel;
 239
 240                 Uri.Builder builder = new Uri.Builder()
 241                         .scheme("otpauth")
 242                         .path(issuerLabel)
 243                         .appendQueryParameter("secret", Base32String.encode(mSecret))
 244                         .appendQueryParameter("issuer", mIssuerInt == null ? mIssuerExt : mIssuerInt)
 245                         .appendQueryParameter("algorithm", mAlgorithm)
 246                         .appendQueryParameter("digits", Integer.toString(mDigits));
 247
 248                 switch (mType) {
 249                 case HOTP:
 250                         builder.authority("hotp");
 251                         builder.appendQueryParameter("counter", Long.toString(mCounter + 1));
 252                         break;
 253                 case TOTP:
 254                         builder.authority("totp");
 255                         builder.appendQueryParameter("period", Integer.toString(mPeriod));
 256                         break;
 257                 }
 258
 259                 return builder.build();
 260         }
 261
 262         @Override
 263         public String toString() {
 264                 return toUri().toString();
 265         }
 266 }