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
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
|
/*
* Copyright (c) 2010 SURFnet bv
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
* IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
* IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/*****************************************************************************
SecureDataManager.cpp
The secure data manager main class. Every token instance has a secure data
manager instance member that is used to decrypt and encrypt sensitive object
attributes such as key material. The secure data manager maintains a key blob
containing a 256-bit AES key that is used in this decryption and encryption
process. The key blob itself is encrypted using a PBE derived key that is
derived from the user PIN and a PBE key that is derived from the SO PIN. It
is up to the token to enforce access control based on which user is logged
in; authentication using the SO PIN is required to be able to change the
user PIN. The master key that is used to decrypt/encrypt sensitive attributes
is stored in memory under a mask that is changed every time the key is used.
*****************************************************************************/
#include "config.h"
#include "SecureDataManager.h"
#include "CryptoFactory.h"
#include "AESKey.h"
#include "SymmetricAlgorithm.h"
#include "RFC4880.h"
// Constructors
// Initialise the object; called by all constructors
void SecureDataManager::initObject()
{
// Get an RNG instance
rng = CryptoFactory::i()->getRNG();
// Get an AES implementation
aes = CryptoFactory::i()->getSymmetricAlgorithm(SymAlgo::AES);
// Initialise masking data
mask = new ByteString();
rng->generateRandom(*mask, 32);
// Set the initial login state
soLoggedIn = userLoggedIn = false;
// Set the magic
magic = ByteString("524A52"); // RJR
// Get a mutex
dataMgrMutex = MutexFactory::i()->getMutex();
}
// Constructs a new SecureDataManager for a blank token; actual
// initialisation is done by setting the SO PIN
SecureDataManager::SecureDataManager()
{
initObject();
}
// Constructs a SecureDataManager using the specified key blob
SecureDataManager::SecureDataManager(const ByteString& soPINBlob, const ByteString& userPINBlob)
{
initObject();
// De-serialise the key blob
soEncryptedKey = soPINBlob;
userEncryptedKey = userPINBlob;
}
// Destructor
SecureDataManager::~SecureDataManager()
{
// Recycle the AES instance
CryptoFactory::i()->recycleSymmetricAlgorithm(aes);
// Clean up the mask
delete mask;
MutexFactory::i()->recycleMutex(dataMgrMutex);
}
// Generic function for creating an encrypted version of the key from the specified passphrase
bool SecureDataManager::pbeEncryptKey(const ByteString& passphrase, ByteString& encryptedKey)
{
// Generate salt
ByteString salt;
if (!rng->generateRandom(salt, 8)) return false;
// Derive the key using RFC4880 PBE
AESKey* pbeKey = NULL;
if (!RFC4880::PBEDeriveKey(passphrase, salt, &pbeKey))
{
return false;
}
// Add the salt
encryptedKey.wipe();
encryptedKey += salt;
// Generate random IV
ByteString IV;
if (!rng->generateRandom(IV, aes->getBlockSize())) return false;
// Add the IV
encryptedKey += IV;
// Encrypt the data
ByteString block;
if (!aes->encryptInit(pbeKey, SymMode::CBC, IV))
{
delete pbeKey;
return false;
}
// First, add the magic
if (!aes->encryptUpdate(magic, block))
{
delete pbeKey;
return false;
}
encryptedKey += block;
// Then, add the key itself
ByteString key;
{
MutexLocker lock(dataMgrMutex);
unmask(key);
bool rv = aes->encryptUpdate(key, block);
remask(key);
if (!rv)
{
delete pbeKey;
return false;
}
}
encryptedKey += block;
// And finalise encryption
if (!aes->encryptFinal(block))
{
delete pbeKey;
return false;
}
encryptedKey += block;
delete pbeKey;
return true;
}
// Set the SO PIN (requires either a blank SecureDataManager or the
// SO to have logged in previously)
bool SecureDataManager::setSOPIN(const ByteString& soPIN)
{
// Check the new PIN
if (soPIN.size() == 0)
{
DEBUG_MSG("Zero length PIN specified");
return false;
}
// Check if the SO needs to be logged in
if ((soEncryptedKey.size() > 0) && !soLoggedIn)
{
DEBUG_MSG("SO must be logged in to change the SO PIN");
return false;
}
// If no SO PIN was set, then this is a SecureDataManager for a blank token. This
// means a new key has to be generated
if (soEncryptedKey.size() == 0)
{
ByteString key;
rng->generateRandom(key, 32);
remask(key);
}
return pbeEncryptKey(soPIN, soEncryptedKey);
}
// Set the user PIN (requires either the SO or the user to have logged
// in previously)
bool SecureDataManager::setUserPIN(const ByteString& userPIN)
{
// Check if the SO or the user is logged in
if (!soLoggedIn && !userLoggedIn)
{
DEBUG_MSG("Must be logged in to change the user PIN");
return false;
}
// Check the new PIN
if (userPIN.size() == 0)
{
DEBUG_MSG("Zero length PIN specified");
return false;
}
return pbeEncryptKey(userPIN, userEncryptedKey);
}
// Generic login function
bool SecureDataManager::login(const ByteString& passphrase, const ByteString& encryptedKey)
{
// Log out first
this->logout();
// First, take the salt from the encrypted key
ByteString salt = encryptedKey.substr(0,8);
// Then, take the IV from the encrypted key
ByteString IV = encryptedKey.substr(8, aes->getBlockSize());
// Now, take the encrypted data from the encrypted key
ByteString encryptedKeyData = encryptedKey.substr(8 + aes->getBlockSize());
// Derive the PBE key
AESKey* pbeKey = NULL;
if (!RFC4880::PBEDeriveKey(passphrase, salt, &pbeKey))
{
return false;
}
// Decrypt the key data
ByteString decryptedKeyData;
ByteString finalBlock;
// NOTE: The login will fail here if incorrect passphrase is supplied
if (!aes->decryptInit(pbeKey, SymMode::CBC, IV) ||
!aes->decryptUpdate(encryptedKeyData, decryptedKeyData) ||
!aes->decryptFinal(finalBlock))
{
delete pbeKey;
return false;
}
delete pbeKey;
decryptedKeyData += finalBlock;
// Check the magic
if (decryptedKeyData.substr(0, 3) != magic)
{
// The passphrase was incorrect
DEBUG_MSG("Incorrect passphrase supplied");
return false;
}
// Strip off the magic
ByteString key = decryptedKeyData.substr(3);
// And mask the key
decryptedKeyData.wipe();
MutexLocker lock(dataMgrMutex);
remask(key);
return true;
}
// Log in using the SO PIN
bool SecureDataManager::loginSO(const ByteString& soPIN)
{
return (soLoggedIn = login(soPIN, soEncryptedKey));
}
// Log in using the user PIN
bool SecureDataManager::loginUser(const ByteString& userPIN)
{
return (userLoggedIn = login(userPIN, userEncryptedKey));
}
// Generic re-authentication function
bool SecureDataManager::reAuthenticate(const ByteString& passphrase, const ByteString& encryptedKey)
{
// First, take the salt from the encrypted key
ByteString salt = encryptedKey.substr(0,8);
// Then, take the IV from the encrypted key
ByteString IV = encryptedKey.substr(8, aes->getBlockSize());
// Now, take the encrypted data from the encrypted key
ByteString encryptedKeyData = encryptedKey.substr(8 + aes->getBlockSize());
// Derive the PBE key
AESKey* pbeKey = NULL;
if (!RFC4880::PBEDeriveKey(passphrase, salt, &pbeKey))
{
return false;
}
// Decrypt the key data
ByteString decryptedKeyData;
ByteString finalBlock;
// NOTE: The login will fail here if incorrect passphrase is supplied
if (!aes->decryptInit(pbeKey, SymMode::CBC, IV) ||
!aes->decryptUpdate(encryptedKeyData, decryptedKeyData) ||
!aes->decryptFinal(finalBlock))
{
delete pbeKey;
return false;
}
delete pbeKey;
decryptedKeyData += finalBlock;
// Check the magic
if (decryptedKeyData.substr(0, 3) != magic)
{
// The passphrase was incorrect
DEBUG_MSG("Incorrect passphrase supplied");
return false;
}
// And mask the key
decryptedKeyData.wipe();
return true;
}
// Re-authenticate the SO
bool SecureDataManager::reAuthenticateSO(const ByteString& soPIN)
{
return reAuthenticate(soPIN, soEncryptedKey);
}
// Re-authenticate the user
bool SecureDataManager::reAuthenticateUser(const ByteString& userPIN)
{
return reAuthenticate(userPIN, userEncryptedKey);
}
// Log out
void SecureDataManager::logout()
{
MutexLocker lock(dataMgrMutex);
// Clear the logged in state
soLoggedIn = userLoggedIn = false;
// Clear the masked key
maskedKey.wipe();
}
// Decrypt the supplied data
bool SecureDataManager::decrypt(const ByteString& encrypted, ByteString& plaintext)
{
// Check the object logged in state
if ((!userLoggedIn && !soLoggedIn) || (maskedKey.size() != 32))
{
return false;
}
// Do not attempt decryption of empty byte strings
if (encrypted.size() == 0)
{
plaintext = ByteString("");
return true;
}
AESKey theKey(256);
ByteString unmaskedKey;
{
MutexLocker lock(dataMgrMutex);
unmask(unmaskedKey);
theKey.setKeyBits(unmaskedKey);
remask(unmaskedKey);
}
// Take the IV from the input data
ByteString IV = encrypted.substr(0, aes->getBlockSize());
if (IV.size() != aes->getBlockSize())
{
ERROR_MSG("Invalid IV in encrypted data");
return false;
}
ByteString finalBlock;
if (!aes->decryptInit(&theKey, SymMode::CBC, IV) ||
!aes->decryptUpdate(encrypted.substr(aes->getBlockSize()), plaintext) ||
!aes->decryptFinal(finalBlock))
{
return false;
}
plaintext += finalBlock;
return true;
}
// Encrypt the supplied data
bool SecureDataManager::encrypt(const ByteString& plaintext, ByteString& encrypted)
{
// Check the object logged in state
if ((!userLoggedIn && !soLoggedIn) || (maskedKey.size() != 32))
{
return false;
}
AESKey theKey(256);
ByteString unmaskedKey;
{
MutexLocker lock(dataMgrMutex);
unmask(unmaskedKey);
theKey.setKeyBits(unmaskedKey);
remask(unmaskedKey);
}
// Wipe encrypted data block
encrypted.wipe();
// Generate random IV
ByteString IV;
if (!rng->generateRandom(IV, aes->getBlockSize())) return false;
ByteString finalBlock;
if (!aes->encryptInit(&theKey, SymMode::CBC, IV) ||
!aes->encryptUpdate(plaintext, encrypted) ||
!aes->encryptFinal(finalBlock))
{
return false;
}
encrypted += finalBlock;
// Add IV to output data
encrypted = IV + encrypted;
return true;
}
// Returns the key blob for the SO PIN
ByteString SecureDataManager::getSOPINBlob()
{
return soEncryptedKey;
}
// Returns the key blob for the user PIN
ByteString SecureDataManager::getUserPINBlob()
{
return userEncryptedKey;
}
// Unmask the key
void SecureDataManager::unmask(ByteString& key)
{
key = maskedKey;
key ^= *mask;
}
// Remask the key
void SecureDataManager::remask(ByteString& key)
{
// Generate a new mask
rng->generateRandom(*mask, 32);
key ^= *mask;
maskedKey = key;
}
// Check if the SO is logged in
bool SecureDataManager::isSOLoggedIn()
{
return soLoggedIn;
}
// Check if the user is logged in
bool SecureDataManager::isUserLoggedIn()
{
return userLoggedIn;
}
|