aboutsummaryrefslogtreecommitdiffstats
path: root/src/lib/tls/tls_handshake_state.cpp
blob: 4a6714f15c0530c76b2ec69782e13adc24bcee98 (plain)
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
/*
* TLS Handshaking
* (C) 2004-2006,2011,2012 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include <botan/internal/tls_handshake_state.h>
#include <botan/internal/tls_messages.h>
#include <botan/internal/tls_record.h>

namespace Botan {

namespace TLS {

namespace {

u32bit bitmask_for_handshake_type(Handshake_Type type)
   {
   switch(type)
      {
      case HELLO_VERIFY_REQUEST:
         return (1 << 0);

      case HELLO_REQUEST:
         return (1 << 1);

      /*
      * Same code point for both client hello styles
      */
      case CLIENT_HELLO:
      case CLIENT_HELLO_SSLV2:
         return (1 << 2);

      case SERVER_HELLO:
         return (1 << 3);

      case CERTIFICATE:
         return (1 << 4);

      case CERTIFICATE_URL:
         return (1 << 5);

      case CERTIFICATE_STATUS:
         return (1 << 6);

      case SERVER_KEX:
         return (1 << 7);

      case CERTIFICATE_REQUEST:
         return (1 << 8);

      case SERVER_HELLO_DONE:
         return (1 << 9);

      case CERTIFICATE_VERIFY:
         return (1 << 10);

      case CLIENT_KEX:
         return (1 << 11);

      case NEXT_PROTOCOL:
         return (1 << 12);

      case NEW_SESSION_TICKET:
         return (1 << 13);

      case HANDSHAKE_CCS:
         return (1 << 14);

      case FINISHED:
         return (1 << 15);

      // allow explicitly disabling new handshakes
      case HANDSHAKE_NONE:
         return 0;
      }

   throw Internal_Error("Unknown handshake type " + std::to_string(type));
   }

}

/*
* Initialize the SSL/TLS Handshake State
*/
Handshake_State::Handshake_State(Handshake_IO* io,
                                 std::function<void (const Handshake_Message&)> msg_callback) :
   m_msg_callback(msg_callback),
   m_handshake_io(io),
   m_version(m_handshake_io->initial_record_version())
   {
   }

Handshake_State::~Handshake_State() {}

void Handshake_State::hello_verify_request(const Hello_Verify_Request& hello_verify)
   {
   note_message(hello_verify);

   m_client_hello->update_hello_cookie(hello_verify);
   hash().reset();
   hash().update(handshake_io().send(*m_client_hello));
   note_message(*m_client_hello);
   }

void Handshake_State::client_hello(Client_Hello* client_hello)
   {
   m_client_hello.reset(client_hello);
   note_message(*m_client_hello);
   }

void Handshake_State::server_hello(Server_Hello* server_hello)
   {
   m_server_hello.reset(server_hello);
   m_ciphersuite = Ciphersuite::by_id(m_server_hello->ciphersuite());
   note_message(*m_server_hello);
   }

void Handshake_State::server_certs(Certificate* server_certs)
   {
   m_server_certs.reset(server_certs);
   note_message(*m_server_certs);
   }

void Handshake_State::server_kex(Server_Key_Exchange* server_kex)
   {
   m_server_kex.reset(server_kex);
   note_message(*m_server_kex);
   }

void Handshake_State::cert_req(Certificate_Req* cert_req)
   {
   m_cert_req.reset(cert_req);
   note_message(*m_cert_req);
   }

void Handshake_State::server_hello_done(Server_Hello_Done* server_hello_done)
   {
   m_server_hello_done.reset(server_hello_done);
   note_message(*m_server_hello_done);
   }

void Handshake_State::client_certs(Certificate* client_certs)
   {
   m_client_certs.reset(client_certs);
   note_message(*m_client_certs);
   }

void Handshake_State::client_kex(Client_Key_Exchange* client_kex)
   {
   m_client_kex.reset(client_kex);
   note_message(*m_client_kex);
   }

void Handshake_State::client_verify(Certificate_Verify* client_verify)
   {
   m_client_verify.reset(client_verify);
   note_message(*m_client_verify);
   }

void Handshake_State::next_protocol(Next_Protocol* next_protocol)
   {
   m_next_protocol.reset(next_protocol);
   note_message(*m_next_protocol);
   }

void Handshake_State::new_session_ticket(New_Session_Ticket* new_session_ticket)
   {
   m_new_session_ticket.reset(new_session_ticket);
   note_message(*m_new_session_ticket);
   }

void Handshake_State::server_finished(Finished* server_finished)
   {
   m_server_finished.reset(server_finished);
   note_message(*m_server_finished);
   }

void Handshake_State::client_finished(Finished* client_finished)
   {
   m_client_finished.reset(client_finished);
   note_message(*m_client_finished);
   }

void Handshake_State::set_version(const Protocol_Version& version)
   {
   m_version = version;
   }

void Handshake_State::compute_session_keys()
   {
   m_session_keys = Session_Keys(this, client_kex()->pre_master_secret(), false);
   }

void Handshake_State::compute_session_keys(const secure_vector<byte>& resume_master_secret)
   {
   m_session_keys = Session_Keys(this, resume_master_secret, true);
   }

void Handshake_State::confirm_transition_to(Handshake_Type handshake_msg)
   {
   const u32bit mask = bitmask_for_handshake_type(handshake_msg);

   m_hand_received_mask |= mask;

   const bool ok = (m_hand_expecting_mask & mask); // overlap?

   if(!ok)
      throw Unexpected_Message("Unexpected state transition in handshake, got " +
                               std::to_string(handshake_msg) +
                               " expected " + std::to_string(m_hand_expecting_mask) +
                               " received " + std::to_string(m_hand_received_mask));

   /* We don't know what to expect next, so force a call to
      set_expected_next; if it doesn't happen, the next transition
      check will always fail which is what we want.
   */
   m_hand_expecting_mask = 0;
   }

void Handshake_State::set_expected_next(Handshake_Type handshake_msg)
   {
   m_hand_expecting_mask |= bitmask_for_handshake_type(handshake_msg);
   }

bool Handshake_State::received_handshake_msg(Handshake_Type handshake_msg) const
   {
   const u32bit mask = bitmask_for_handshake_type(handshake_msg);

   return (m_hand_received_mask & mask);
   }

std::pair<Handshake_Type, std::vector<byte>>
Handshake_State::get_next_handshake_msg()
   {
   const bool expecting_ccs =
      (bitmask_for_handshake_type(HANDSHAKE_CCS) & m_hand_expecting_mask);

   return m_handshake_io->get_next_record(expecting_ccs);
   }

std::string Handshake_State::srp_identifier() const
   {
   if(ciphersuite().valid() && ciphersuite().kex_algo() == "SRP_SHA")
      return client_hello()->srp_identifier();

   return "";
   }

std::vector<byte> Handshake_State::session_ticket() const
   {
   if(new_session_ticket() && !new_session_ticket()->ticket().empty())
      return new_session_ticket()->ticket();

   return client_hello()->session_ticket();
   }

KDF* Handshake_State::protocol_specific_prf() const
   {
   if(version() == Protocol_Version::SSL_V3)
      {
      return get_kdf("SSL3-PRF");
      }
   else if(version().supports_ciphersuite_specific_prf())
      {
      const std::string prf_algo = ciphersuite().prf_algo();

      if(prf_algo == "MD5" || prf_algo == "SHA-1")
         return get_kdf("TLS-12-PRF(SHA-256)");

      return get_kdf("TLS-12-PRF(" + prf_algo + ")");
      }
   else
      {
      // TLS v1.0, v1.1 and DTLS v1.0
      return get_kdf("TLS-PRF");
      }

   throw Internal_Error("Unknown version code " + version().to_string());
   }

namespace {

std::string choose_hash(const std::string& sig_algo,
                        Protocol_Version negotiated_version,
                        const Policy& policy,
                        bool for_client_auth,
                        const Client_Hello* client_hello,
                        const Certificate_Req* cert_req)
   {
   if(!negotiated_version.supports_negotiable_signature_algorithms())
      {
      if(for_client_auth && negotiated_version == Protocol_Version::SSL_V3)
         return "Raw";

      if(sig_algo == "RSA")
         return "Parallel(MD5,SHA-160)";

      if(sig_algo == "DSA")
         return "SHA-1";

      if(sig_algo == "ECDSA")
         return "SHA-1";

      throw Internal_Error("Unknown TLS signature algo " + sig_algo);
      }

   const auto supported_algos = for_client_auth ?
      cert_req->supported_algos() :
      client_hello->supported_algos();

   if(!supported_algos.empty())
      {
      const auto hashes = policy.allowed_signature_hashes();

      /*
      * Choose our most preferred hash that the counterparty supports
      * in pairing with the signature algorithm we want to use.
      */
      for(auto hash : hashes)
         {
         for(auto algo : supported_algos)
            {
            if(algo.first == hash && algo.second == sig_algo)
               return hash;
            }
         }
      }

   // TLS v1.2 default hash if the counterparty sent nothing
   return "SHA-1";
   }

}

std::pair<std::string, Signature_Format>
Handshake_State::choose_sig_format(const Private_Key& key,
                                   std::string& hash_algo_out,
                                   std::string& sig_algo_out,
                                   bool for_client_auth,
                                   const Policy& policy) const
   {
   const std::string sig_algo = key.algo_name();

   const std::string hash_algo =
      choose_hash(sig_algo,
                  this->version(),
                  policy,
                  for_client_auth,
                  client_hello(),
                  cert_req());

   if(this->version().supports_negotiable_signature_algorithms())
      {
      hash_algo_out = hash_algo;
      sig_algo_out = sig_algo;
      }

   if(sig_algo == "RSA")
      {
      const std::string padding = "EMSA3(" + hash_algo + ")";

      return std::make_pair(padding, IEEE_1363);
      }
   else if(sig_algo == "DSA" || sig_algo == "ECDSA")
      {
      const std::string padding = "EMSA1(" + hash_algo + ")";

      return std::make_pair(padding, DER_SEQUENCE);
      }

   throw Invalid_Argument(sig_algo + " is invalid/unknown for TLS signatures");
   }

std::pair<std::string, Signature_Format>
Handshake_State::understand_sig_format(const Public_Key& key,
                                       std::string hash_algo,
                                       std::string sig_algo,
                                       bool for_client_auth) const
   {
   const std::string algo_name = key.algo_name();

   /*
   FIXME: This should check what was sent against the client hello
   preferences, or the certificate request, to ensure it was allowed
   by those restrictions.

   Or not?
   */

   if(this->version().supports_negotiable_signature_algorithms())
      {
      if(hash_algo == "")
         throw Decoding_Error("Counterparty did not send hash/sig IDS");

      if(sig_algo != algo_name)
         throw Decoding_Error("Counterparty sent inconsistent key and sig types");
      }
   else
      {
      if(hash_algo != "" || sig_algo != "")
         throw Decoding_Error("Counterparty sent hash/sig IDs with old version");
      }

   if(algo_name == "RSA")
      {
      if(for_client_auth && this->version() == Protocol_Version::SSL_V3)
         {
         hash_algo = "Raw";
         }
      else if(!this->version().supports_negotiable_signature_algorithms())
         {
         hash_algo = "Parallel(MD5,SHA-160)";
         }

      const std::string padding = "EMSA3(" + hash_algo + ")";
      return std::make_pair(padding, IEEE_1363);
      }
   else if(algo_name == "DSA" || algo_name == "ECDSA")
      {
      if(algo_name == "DSA" && for_client_auth && this->version() == Protocol_Version::SSL_V3)
         {
         hash_algo = "Raw";
         }
      else if(!this->version().supports_negotiable_signature_algorithms())
         {
         hash_algo = "SHA-1";
         }

      const std::string padding = "EMSA1(" + hash_algo + ")";

      return std::make_pair(padding, DER_SEQUENCE);
      }

   throw Invalid_Argument(algo_name + " is invalid/unknown for TLS signatures");
   }

}

}