summaryrefslogtreecommitdiff
path: root/src/keyDerivation.cpp
blob: c091ee641b606a0e263a4e34f2bf87e3e014971b (plain) (blame)
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
/*
 *  anytun
 *
 *  The secure anycast tunneling protocol (satp) defines a protocol used
 *  for communication between any combination of unicast and anycast
 *  tunnel endpoints.  It has less protocol overhead than IPSec in Tunnel
 *  mode and allows tunneling of every ETHER TYPE protocol (e.g.
 *  ethernet, ip, arp ...). satp directly includes cryptography and
 *  message authentication based on the methodes used by SRTP.  It is
 *  intended to deliver a generic, scaleable and secure solution for
 *  tunneling and relaying of packets of any protocol.
 *
 *
 *  Copyright (C) 2007-2008 Othmar Gsenger, Erwin Nindl, 
 *                          Christian Pointner <satp@wirdorange.org>
 *
 *  This file is part of Anytun.
 *
 *  Anytun is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 3 as
 *  published by the Free Software Foundation.
 *
 *  Anytun is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with anytun.  If not, see <http://www.gnu.org/licenses/>.
 */


#include "log.h"
#include "anytunError.h"
#include "keyDerivation.h"
#include "threadUtils.hpp"
#include "datatypes.h"
#include "endian.h"

#include <stdexcept>
#include <iostream>
#include <sstream>
#include <string>

#ifndef NO_CRYPT
#ifndef NO_PASSPHRASE
#ifdef USE_SSL_CRYPTO
#include <openssl/sha.h>
#endif
#endif
#endif

void KeyDerivation::setLogKDRate(const int8_t log_rate)
{
  WritersLock lock(mutex_);
  ld_kdr_ = log_rate;
  if(ld_kdr_ > (int8_t)(sizeof(seq_nr_t) * 8))
    ld_kdr_ = sizeof(seq_nr_t) * 8;
}

#ifndef NO_CRYPT
#ifndef NO_PASSPHRASE
void KeyDerivation::calcMasterKey(std::string passphrase, u_int16_t length)
{
  cLog.msg(Log::PRIO_NOTICE) << "KeyDerivation: calculating master key from passphrase";
  if(!length) {
    cLog.msg(Log::PRIO_ERR) << "KeyDerivation: bad master key length";
    return;
  }

#ifndef USE_SSL_CRYPTO
  if(length > gcry_md_get_algo_dlen(GCRY_MD_SHA256)) {
#else
  if(length > SHA256_DIGEST_LENGTH) {
#endif
    cLog.msg(Log::PRIO_ERR) << "KeyDerivation: master key too long for passphrase algorithm";
    return;
  }

#ifndef USE_SSL_CRYPTO
  Buffer digest(gcry_md_get_algo_dlen(GCRY_MD_SHA256));
  gcry_md_hash_buffer(GCRY_MD_SHA256, digest.getBuf(), passphrase.c_str(), passphrase.length());
#else
  Buffer digest(u_int32_t(SHA256_DIGEST_LENGTH));
  SHA256(reinterpret_cast<const unsigned char*>(passphrase.c_str()), passphrase.length(), digest.getBuf());
#endif
  master_key_.setLength(length);

  memcpy(master_key_.getBuf(), &digest.getBuf()[digest.getLength() - master_key_.getLength()], master_key_.getLength());
}

void KeyDerivation::calcMasterSalt(std::string passphrase, u_int16_t length)
{
  cLog.msg(Log::PRIO_NOTICE) << "KeyDerivation: calculating master salt from passphrase";
  if(!length) {
    cLog.msg(Log::PRIO_ERR) << "KeyDerivation: bad master salt length";
    return;
  }

#ifndef USE_SSL_CRYPTO
  if(length > gcry_md_get_algo_dlen(GCRY_MD_SHA1)) {
#else
  if(length > SHA_DIGEST_LENGTH) {
#endif
    cLog.msg(Log::PRIO_ERR) << "KeyDerivation: master key too long for passphrase algorithm";
    return;
  }

#ifndef USE_SSL_CRYPTO
  Buffer digest(gcry_md_get_algo_dlen(GCRY_MD_SHA1));
  gcry_md_hash_buffer(GCRY_MD_SHA1, digest.getBuf(), passphrase.c_str(), passphrase.length());
#else
  Buffer digest(u_int32_t(SHA_DIGEST_LENGTH));
  SHA1(reinterpret_cast<const unsigned char*>(passphrase.c_str()), passphrase.length(), digest.getBuf());
#endif
  master_salt_.setLength(length);

  memcpy(master_salt_.getBuf(), &digest.getBuf()[digest.getLength() - master_salt_.getLength()], master_salt_.getLength());
}
#endif
#endif

//****** NullKeyDerivation ******

bool NullKeyDerivation::generate(kd_dir_t dir, satp_prf_label_t label, seq_nr_t seq_nr, Buffer& key)
{
  std::memset(key.getBuf(), 0, key.getLength());
  return true;
}

#ifndef NO_CRYPT
//****** AesIcmKeyDerivation ******

AesIcmKeyDerivation::AesIcmKeyDerivation() : KeyDerivation(DEFAULT_KEY_LENGTH) 
{
#ifndef USE_SSL_CRYPTO
  for(int i=0; i<2; i++)
    handle_[i] = NULL;
#endif
}

AesIcmKeyDerivation::AesIcmKeyDerivation(bool a) : KeyDerivation(a, DEFAULT_KEY_LENGTH) 
{
#ifndef USE_SSL_CRYPTO
  for(int i=0; i<2; i++)
    handle_[i] = NULL;
#endif
}

AesIcmKeyDerivation::AesIcmKeyDerivation(u_int16_t key_length) : KeyDerivation(key_length) 
{
#ifndef USE_SSL_CRYPTO
  for(int i=0; i<2; i++)
    handle_[i] = NULL;
#endif
}

AesIcmKeyDerivation::AesIcmKeyDerivation(bool a, u_int16_t key_length) : KeyDerivation(a, key_length) 
{
#ifndef USE_SSL_CRYPTO
  for(int i=0; i<2; i++)
    handle_[i] = NULL;
#endif
}

AesIcmKeyDerivation::~AesIcmKeyDerivation()
{
  WritersLock lock(mutex_);
#ifndef USE_SSL_CRYPTO
  for(int i=0; i<2; i++)
    if(handle_[i])
      gcry_cipher_close(handle_[i]);
#endif
}

void AesIcmKeyDerivation::init(Buffer key, Buffer salt, std::string passphrase)
{
  WritersLock lock(mutex_);
  
  is_initialized_ = false;
#ifndef NO_PASSPHRASE
  if(passphrase != "" && !key.getLength())
    calcMasterKey(passphrase, key_length_/8);
  else
    master_key_ = SyncBuffer(key);
  
  if(passphrase != "" && !salt.getLength())
    calcMasterSalt(passphrase, SALT_LENGTH);
  else
    master_salt_ = SyncBuffer(salt);
#else
  master_key_ = SyncBuffer(key);
  master_salt_ = SyncBuffer(salt);
#endif

  updateMasterKey();
}

void AesIcmKeyDerivation::updateMasterKey()
{
  if(master_key_.getLength()*8 != key_length_) {
    cLog.msg(Log::PRIO_CRIT) << "KeyDerivation::updateMasterKey: key lengths don't match";
    return;
  }

  if(master_salt_.getLength() != SALT_LENGTH) {
    cLog.msg(Log::PRIO_CRIT) << "KeyDerivation::updateMasterKey: salt lengths don't match";
    return;
  }

#ifndef USE_SSL_CRYPTO
  int algo;
  switch(key_length_) {
  case 128: algo = GCRY_CIPHER_AES128; break;
  case 192: algo = GCRY_CIPHER_AES192; break;
  case 256: algo = GCRY_CIPHER_AES256; break;
  default: {
    cLog.msg(Log::PRIO_CRIT) << "KeyDerivation::updateMasterKey: cipher key length of " << key_length_ << " Bits is not supported";
    return;
  }
  }

  for(int i=0; i<2; i++) {
    if(handle_[i])
      gcry_cipher_close(handle_[i]);
    
    gcry_error_t err = gcry_cipher_open(&handle_[i], algo, GCRY_CIPHER_MODE_CTR, 0);
    if(err) {
      cLog.msg(Log::PRIO_ERR) << "KeyDerivation::updateMasterKey: Failed to open cipher: " << AnytunGpgError(err);
      return;
    } 
    
    err = gcry_cipher_setkey(handle_[i], master_key_.getBuf(), master_key_.getLength());
    if(err) {
      cLog.msg(Log::PRIO_ERR) << "KeyDerivation::updateMasterKey: Failed to set cipher key: " << AnytunGpgError(err);
      return;
    }
  }
#else
  for(int i=0; i<2; i++) {
    int ret = AES_set_encrypt_key(master_key_.getBuf(), master_key_.getLength()*8, &aes_key_[i]);
    if(ret) {
      cLog.msg(Log::PRIO_ERR) << "KeyDerivation::updateMasterKey: Failed to set ssl key (code: " << ret << ")";
      return;
    }
  }
#endif
  is_initialized_ = true;
}

std::string AesIcmKeyDerivation::printType() 
{
  ReadersLock lock(mutex_);

  std::stringstream sstr;
  sstr << "AesIcm" << key_length_ << "KeyDerivation";
  return sstr.str();
}

bool AesIcmKeyDerivation::calcCtr(kd_dir_t dir, seq_nr_t* r, satp_prf_label_t label, seq_nr_t seq_nr)
{
  *r = 0;
  if(ld_kdr_ >= 0)
    *r = seq_nr >> ld_kdr_;

  if(key_store_[dir][label].key_.getLength() && key_store_[dir][label].r_ == *r) {
    if(!(*r) || (seq_nr % (*r)))
      return false;
  }

  if(master_salt_.getLength() != SALT_LENGTH) {
    cLog.msg(Log::PRIO_CRIT) << "KeyDerivation::calcCtr: salt lengths don't match";
    return false;
  }
  memcpy(ctr_[dir].salt_.buf_, master_salt_.getBuf(), SALT_LENGTH);
  ctr_[dir].salt_.zero_ = 0;
  if(anytun02_compat_) {
    ctr_[dir].params_compat_.label_ ^= label;
    ctr_[dir].params_compat_.r_ ^= SEQ_NR_T_HTON(*r);
  }
  else {
    ctr_[dir].params_.label_ ^= label;
    ctr_[dir].params_.r_ ^= SEQ_NR_T_HTON(*r);
  }

  return true;
}

bool AesIcmKeyDerivation::generate(kd_dir_t dir, satp_prf_label_t label, seq_nr_t seq_nr, Buffer& key) 
{
  ReadersLock lock(mutex_);

  if(!is_initialized_)
    return false;

  seq_nr_t r;
  calcCtr(dir, &r, label, seq_nr);
  bool result = calcCtr(dir, &r, label, seq_nr);
  if(!result) {
    u_int32_t len = key.getLength();
    if(len > key_store_[dir][label].key_.getLength()) {
      cLog.msg(Log::PRIO_WARNING) << "KeyDerivation::generate: stored (old) key for label " << label << " is too short, filling with zeros";
      std::memset(key.getBuf(), 0, len);
      len = key_store_[dir][label].key_.getLength();
    }
    std::memcpy(key.getBuf(), key_store_[dir][label].key_.getBuf(), len);
    return false;
  }
  
#ifndef USE_SSL_CRYPTO
  gcry_error_t err = gcry_cipher_reset(handle_[dir]);
  if(err) {
    cLog.msg(Log::PRIO_ERR) << "KeyDerivation::generate: Failed to reset cipher: " << AnytunGpgError(err);
  }

  err = gcry_cipher_setctr(handle_[dir], ctr_[dir].buf_, CTR_LENGTH);
  if(err) {
    cLog.msg(Log::PRIO_ERR) << "KeyDerivation::generate: Failed to set CTR: " << AnytunGpgError(err);
    return false;
  }

  std::memset(key.getBuf(), 0, key.getLength());
  err = gcry_cipher_encrypt(handle_[dir], key, key.getLength(), NULL, 0);
  if(err) {
    cLog.msg(Log::PRIO_ERR) << "KeyDerivation::generate: Failed to generate cipher bitstream: " << AnytunGpgError(err);
  }
  return true;
#else
  if(CTR_LENGTH != AES_BLOCK_SIZE) {
    cLog.msg(Log::PRIO_ERR) << "AesIcmCipher: Failed to set cipher CTR: size don't fits";
    return false;
  }
  unsigned int num = 0;
  std::memset(ecount_buf_[dir], 0, AES_BLOCK_SIZE);
  std::memset(key.getBuf(), 0, key.getLength());
  AES_ctr128_encrypt(key.getBuf(), key.getBuf(), key.getLength(), &aes_key_[dir], ctr_[dir].buf_, ecount_buf_[dir], &num);
#endif
  
  if(!ld_kdr_)
    return true;

  if(key_store_[dir][label].key_.getLength() < key.getLength()) {
    key_store_[dir][label].key_.setLength(key.getLength());
  }

  std::memcpy(key_store_[dir][label].key_.getBuf(), key.getBuf(), key.getLength());
  key_store_[dir][label].r_ = r;

  return true;
}
#endif