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[people/ms/strongswan.git] / Source / charon / sa / authenticator.c
1 /**
2 * @file authenticator.c
3 *
4 * @brief Implementation of authenticator_t.
5 *
6 */
7
8 /*
9 * Copyright (C) 2005 Jan Hutter, Martin Willi
10 * Hochschule fuer Technik Rapperswil
11 *
12 * This program is free software; you can redistribute it and/or modify it
13 * under the terms of the GNU General Public License as published by the
14 * Free Software Foundation; either version 2 of the License, or (at your
15 * option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
16 *
17 * This program is distributed in the hope that it will be useful, but
18 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
19 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
20 * for more details.
21 */
22
23 #include "authenticator.h"
24
25 #include <utils/allocator.h>
26 #include <daemon.h>
27
28 /**
29 * Key pad for the AUTH method SHARED_KEY_MESSAGE_INTEGRITY_CODE.
30 */
31 #define IKE_V2_KEY_PAD "Key Pad for IKEv2"
32
33 /**
34 * Length of key pad in bytes.
35 */
36 #define IKE_V2_KEY_PAD_LEN strlen(IKE_V2_KEY_PAD)
37
38
39 typedef struct private_authenticator_t private_authenticator_t;
40
41 /**
42 * Private data of an authenticator_t object.
43 */
44 struct private_authenticator_t {
45
46 /**
47 * Public authenticator_t interface.
48 */
49 authenticator_t public;
50
51 /**
52 * Assigned IKE_SA. Needed to get objects of type prf_t, sa_config_t and logger_t.
53 */
54 protected_ike_sa_t *ike_sa;
55
56 /**
57 * PRF taken from the IKE_SA.
58 */
59 prf_t *prf;
60
61 /**
62 * A logger for.
63 *
64 * Using logger of IKE_SA.
65 */
66 logger_t *logger;
67
68 /**
69 * @brief Creates the octets which are signed (RSA) or MACed (shared secret) as described in section
70 * 2.15 of draft.
71 *
72 * @param this calling object
73 * @param last_message the last message to include in created octets
74 * (either binary form of IKE_SA_INIT request or IKE_SA_INIT response)
75 * @param other_nonce Nonce data received from other peer
76 * @param my_id id_payload_t object representing an ID payload
77 * @param initiator Type of peer. TRUE, if it is original initiator, FALSE otherwise
78 * @return octets as described in section 2.15. Memory gets allocated and has to get
79 * destroyed by caller.
80 */
81 chunk_t (*allocate_octets) (private_authenticator_t *this,
82 chunk_t last_message,
83 chunk_t other_nonce,
84 id_payload_t *my_id,
85 bool initiator);
86
87 /**
88 * @brief Creates the AUTH data using auth method SHARED_KEY_MESSAGE_INTEGRITY_CODE.
89 *
90 * @param this calling object
91 * @param last_message the last message
92 * (either binary form of IKE_SA_INIT request or IKE_SA_INIT response)
93 * @param nonce Nonce data to include in auth data compution
94 * @param id_payload id_payload_t object representing an ID payload
95 * @param initiator Type of peer. TRUE, if it is original initiator, FALSE otherwise
96 * @param shared_secret shared secret as chunk_t. If shared secret is a string,
97 * the NULL termination is not included.
98 * @return AUTH data as dscribed in section 2.15 for
99 * AUTH method SHARED_KEY_MESSAGE_INTEGRITY_CODE.
100 * Memory gets allocated and has to get destroyed by caller.
101 */
102 chunk_t (*allocate_auth_data_with_preshared_secret) (private_authenticator_t *this,
103 chunk_t last_message,
104 chunk_t nonce,
105 id_payload_t *id_payload,
106 bool initiator,
107 chunk_t preshared_secret);
108 };
109
110 /**
111 * Implementation of private_authenticator_t.allocate_octets.
112 */
113 static chunk_t allocate_octets(private_authenticator_t *this,
114 chunk_t last_message,
115 chunk_t other_nonce,
116 id_payload_t *my_id,
117 bool initiator)
118 {
119 chunk_t id_chunk = my_id->get_data(my_id);
120 u_int8_t id_with_header[4 + id_chunk.len];
121 /*
122 * IKEv2 for linux (http://sf.net/projects/ikev2/)
123 * is not compatible with IKEv2 Draft and so not compatible with this
124 * implementation, cause AUTH data are computed without
125 * ID type and the three reserved bytes.
126 */
127 chunk_t id_with_header_chunk = {ptr:id_with_header, len: sizeof(id_with_header)};
128 u_int8_t *current_pos;
129 chunk_t octets;
130
131 id_with_header[0] = my_id->get_id_type(my_id);
132 /* TODO:
133 * Reserved bytes are not in any case zero.
134 */
135 id_with_header[1] = 0x00;
136 id_with_header[2] = 0x00;
137 id_with_header[3] = 0x00;
138 memcpy(id_with_header + 4,id_chunk.ptr,id_chunk.len);
139
140 if (initiator)
141 {
142 this->prf->set_key(this->prf,this->ike_sa->get_key_pi(this->ike_sa));
143 }
144 else
145 {
146 this->prf->set_key(this->prf,this->ike_sa->get_key_pr(this->ike_sa));
147 }
148
149
150 /* 4 bytes are id type and reserved fields of id payload */
151 octets.len = last_message.len + other_nonce.len + this->prf->get_block_size(this->prf);
152 octets.ptr = allocator_alloc(octets.len);
153 current_pos = octets.ptr;
154 memcpy(current_pos,last_message.ptr,last_message.len);
155 current_pos += last_message.len;
156 memcpy(current_pos,other_nonce.ptr,other_nonce.len);
157 current_pos += other_nonce.len;
158 this->prf->get_bytes(this->prf,id_with_header_chunk,current_pos);
159
160 this->logger->log_chunk(this->logger,RAW | LEVEL2, "Octets (Mesage + Nonce + prf(Sk_px,Idx)",&octets);
161 return octets;
162 }
163
164 /**
165 * Implementation of private_authenticator_t.allocate_auth_data_with_preshared_secret.
166 */
167 static chunk_t allocate_auth_data_with_preshared_secret (private_authenticator_t *this,
168 chunk_t last_message,
169 chunk_t nonce,
170 id_payload_t *id_payload,
171 bool initiator,
172 chunk_t preshared_secret)
173 {
174 chunk_t key_pad = {ptr: IKE_V2_KEY_PAD, len:IKE_V2_KEY_PAD_LEN};
175 u_int8_t key_buffer[this->prf->get_block_size(this->prf)];
176 chunk_t key = {ptr: key_buffer, len: sizeof(key_buffer)};
177 chunk_t auth_data;
178
179 chunk_t octets = this->allocate_octets(this,last_message,nonce,id_payload,initiator);
180
181 /*
182 * AUTH = prf(prf(Shared Secret,"Key Pad for IKEv2"), <msg octets>)
183 */
184
185 this->prf->set_key(this->prf,preshared_secret);
186 this->prf->get_bytes(this->prf,key_pad,key_buffer);
187 this->prf->set_key(this->prf,key);
188 this->prf->allocate_bytes(this->prf,octets,&auth_data);
189 allocator_free_chunk(&octets);
190 this->logger->log_chunk(this->logger,RAW | LEVEL2, "Authenticated data",&auth_data);
191
192 return auth_data;
193 }
194
195 /**
196 * Implementation of authenticator_t.verify_auth_data.
197 */
198 static status_t verify_auth_data (private_authenticator_t *this,
199 auth_payload_t *auth_payload,
200 chunk_t last_received_packet,
201 chunk_t my_nonce,
202 id_payload_t *other_id_payload,
203 bool initiator)
204 {
205 switch(auth_payload->get_auth_method(auth_payload))
206 {
207 case SHARED_KEY_MESSAGE_INTEGRITY_CODE:
208 {
209 identification_t *other_id = other_id_payload->get_identification(other_id_payload);
210 chunk_t auth_data = auth_payload->get_data(auth_payload);
211 chunk_t preshared_secret;
212 status_t status;
213
214 status = charon->configuration_manager->get_shared_secret(charon->configuration_manager,
215 other_id,
216 &preshared_secret);
217 other_id->destroy(other_id);
218 if (status != SUCCESS)
219 {
220 return status;
221 }
222
223 chunk_t my_auth_data = this->allocate_auth_data_with_preshared_secret(this,
224 last_received_packet,
225 my_nonce,
226 other_id_payload,
227 initiator,
228 preshared_secret);
229
230 if (auth_data.len != my_auth_data.len)
231 {
232 allocator_free_chunk(&my_auth_data);
233 return FAILED;
234 }
235 if (memcmp(auth_data.ptr,my_auth_data.ptr,my_auth_data.len) == 0)
236 {
237 status = SUCCESS;
238 }
239 else
240 {
241 status = FAILED;
242 }
243 allocator_free_chunk(&my_auth_data);
244 return status;
245 }
246 case RSA_DIGITAL_SIGNATURE:
247 {
248 identification_t *other_id = other_id_payload->get_identification(other_id_payload);
249 rsa_public_key_t *public_key;
250 status_t status;
251 chunk_t octets, auth_data;
252
253 auth_data = auth_payload->get_data(auth_payload);
254
255 status = charon->configuration_manager->get_rsa_public_key(charon->configuration_manager,
256 other_id,
257 &public_key);
258 other_id->destroy(other_id);
259 if (status != SUCCESS)
260 {
261 return status;
262 }
263
264 octets = this->allocate_octets(this,last_received_packet,my_nonce,other_id_payload,initiator);
265
266 status = public_key->verify_emsa_pkcs1_signature(public_key, octets, auth_data);
267
268 allocator_free_chunk(&octets);
269 return status;
270 }
271 default:
272 {
273 return NOT_SUPPORTED;
274 }
275 }
276 }
277
278 /**
279 * Implementation of authenticator_t.compute_auth_data.
280 */
281 static status_t compute_auth_data (private_authenticator_t *this,
282 auth_payload_t **auth_payload,
283 chunk_t last_sent_packet,
284 chunk_t other_nonce,
285 id_payload_t *my_id_payload,
286 bool initiator)
287 {
288 sa_config_t *sa_config = this->ike_sa->get_sa_config(this->ike_sa);
289
290 switch(sa_config->get_auth_method(sa_config))
291 {
292 case SHARED_KEY_MESSAGE_INTEGRITY_CODE:
293 {
294 identification_t *my_id =my_id_payload->get_identification(my_id_payload);
295 chunk_t preshared_secret;
296 status_t status;
297
298 status = charon->configuration_manager->get_shared_secret(charon->configuration_manager,
299 my_id,
300 &preshared_secret);
301
302 my_id->destroy(my_id);
303 if (status != SUCCESS)
304 {
305 return status;
306 }
307
308 chunk_t auth_data = this->allocate_auth_data_with_preshared_secret(this,
309 last_sent_packet,
310 other_nonce,
311 my_id_payload,
312 initiator,
313 preshared_secret);
314
315 *auth_payload = auth_payload_create();
316 (*auth_payload)->set_auth_method((*auth_payload),SHARED_KEY_MESSAGE_INTEGRITY_CODE);
317 (*auth_payload)->set_data((*auth_payload),auth_data);
318
319 allocator_free_chunk(&auth_data);
320 return SUCCESS;
321 }
322 case RSA_DIGITAL_SIGNATURE:
323 {
324 identification_t *my_id = my_id_payload->get_identification(my_id_payload);
325 rsa_private_key_t *private_key;
326 status_t status;
327 chunk_t octets, auth_data;
328
329 status = charon->configuration_manager->get_rsa_private_key(charon->configuration_manager,
330 my_id,
331 &private_key);
332 my_id->destroy(my_id);
333 if (status != SUCCESS)
334 {
335 return status;
336 }
337
338 octets = this->allocate_octets(this,last_sent_packet,other_nonce,my_id_payload,initiator);
339
340 status = private_key->build_emsa_pkcs1_signature(private_key, HASH_SHA1, octets, &auth_data);
341 allocator_free_chunk(&octets);
342 if (status != SUCCESS)
343 {
344 return status;
345 }
346
347 *auth_payload = auth_payload_create();
348 (*auth_payload)->set_auth_method((*auth_payload), RSA_DIGITAL_SIGNATURE);
349 (*auth_payload)->set_data((*auth_payload),auth_data);
350
351 allocator_free_chunk(&auth_data);
352 return SUCCESS;
353 }
354 default:
355 {
356 return NOT_SUPPORTED;
357 }
358 }
359 }
360
361 /**
362 * Implementation of authenticator_t.destroy.
363 */
364 static void destroy (private_authenticator_t *this)
365 {
366 allocator_free(this);
367 }
368
369 /*
370 * Described in header.
371 */
372 authenticator_t *authenticator_create(protected_ike_sa_t *ike_sa)
373 {
374 private_authenticator_t *this = allocator_alloc_thing(private_authenticator_t);
375
376 /* Public functions */
377 this->public.destroy = (void(*)(authenticator_t*))destroy;
378 this->public.verify_auth_data = (status_t (*) (authenticator_t *,auth_payload_t *, chunk_t ,chunk_t ,id_payload_t *,bool)) verify_auth_data;
379 this->public.compute_auth_data = (status_t (*) (authenticator_t *,auth_payload_t **, chunk_t ,chunk_t ,id_payload_t *,bool)) compute_auth_data;
380
381 /* private functions */
382 this->allocate_octets = allocate_octets;
383 this->allocate_auth_data_with_preshared_secret = allocate_auth_data_with_preshared_secret;
384
385 /* private data */
386 this->ike_sa = ike_sa;
387 this->prf = this->ike_sa->get_prf(this->ike_sa);
388 this->logger = this->ike_sa->get_logger(this->ike_sa);
389
390 return &(this->public);
391 }
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