- Code documented
[strongswan.git] / Source / charon / sa / authenticator.c
1 /**
2 * @file authenticator.c
3 *
4 * @brief Implementation of authenticator.
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 typedef struct private_authenticator_t private_authenticator_t;
39
40 /**
41 * Private data of an authenticator_t object.
42 */
43 struct private_authenticator_t {
44
45 /**
46 * Public authenticator_t interface.
47 */
48 authenticator_t public;
49
50 /**
51 * Assigned IKE_SA. Needed to get objects of type prf_t, sa_config_t and logger_t.
52 */
53 protected_ike_sa_t *ike_sa;
54
55 /**
56 * PRF taken from the IKE_SA.
57 */
58 prf_t *prf;
59
60 /**
61 * A logger for.
62 *
63 * Using logger of IKE_SA.
64 */
65 logger_t *logger;
66
67 /**
68 * Creates the octets which are signed (RSA) or MACed (shared secret) as described in section
69 * 2.15 of draft.
70 *
71 * @param this calling object
72 * @param last_message the last message to include in created octets
73 * (either binary form of IKE_SA_INIT request or IKE_SA_INIT response)
74 * @param other_nonce Nonce data received from other peer
75 * @param my_id id_payload_t object representing an ID payload
76 * @param initiator Type of peer. TRUE, if it is original initiator, FALSE otherwise
77 * @return octets as described in section 2.15. Memory gets allocated and has to get
78 * destroyed by caller.
79 */
80 chunk_t (*allocate_octets) (private_authenticator_t *this,chunk_t last_message, chunk_t other_nonce,id_payload_t *my_id, bool initiator);
81
82 /**
83 * Creates the AUTH data using auth method SHARED_KEY_MESSAGE_INTEGRITY_CODE.
84 *
85 * @param this calling object
86 * @param last_message the last message
87 * (either binary form of IKE_SA_INIT request or IKE_SA_INIT response)
88 * @param nonce Nonce data to include in auth data compution
89 * @param id_payload id_payload_t object representing an ID payload
90 * @param initiator Type of peer. TRUE, if it is original initiator, FALSE otherwise
91 * @param shared_secret shared secret as chunk_t. If shared secret is a string, the NULL termination is not included.
92 * @return AUTH data as dscribed in section 2.15 for AUTH method SHARED_KEY_MESSAGE_INTEGRITY_CODE.
93 * Memory gets allocated and has to get destroyed by caller.
94 */
95 chunk_t (*allocate_auth_data_with_preshared_secret) (private_authenticator_t *this,chunk_t last_message, chunk_t nonce,id_payload_t *id_payload, bool initiator,chunk_t preshared_secret);
96 };
97
98 /**
99 * Implementation of private_authenticator_t.allocate_octets.
100 */
101 static chunk_t allocate_octets(private_authenticator_t *this,chunk_t last_message, chunk_t other_nonce,id_payload_t *my_id, bool initiator)
102 {
103 chunk_t id_chunk = my_id->get_data(my_id);
104 u_int8_t id_with_header[4 + id_chunk.len];
105 chunk_t id_with_header_chunk = {ptr:id_with_header, len: sizeof(id_with_header) };
106 u_int8_t *current_pos;
107 chunk_t octets;
108
109 id_with_header[0] = my_id->get_id_type(my_id);
110 /* TODO:
111 * Reserved bytes are not in any case zero.
112 */
113 id_with_header[1] = 0x00;
114 id_with_header[2] = 0x00;
115 id_with_header[3] = 0x00;
116 memcpy(id_with_header + 4,id_chunk.ptr,id_chunk.len);
117
118 if (initiator)
119 {
120 this->prf->set_key(this->prf,this->ike_sa->get_key_pi(this->ike_sa));
121 }
122 else
123 {
124 this->prf->set_key(this->prf,this->ike_sa->get_key_pr(this->ike_sa));
125 }
126
127 /* 4 bytes are id type and reserved fields of id payload */
128 octets.len = last_message.len + other_nonce.len + this->prf->get_block_size(this->prf);
129 octets.ptr = allocator_alloc(octets.len);
130 current_pos = octets.ptr;
131 memcpy(current_pos,last_message.ptr,last_message.len);
132 current_pos += last_message.len;
133 memcpy(current_pos,other_nonce.ptr,other_nonce.len);
134 current_pos += other_nonce.len;
135 this->prf->get_bytes(this->prf,id_with_header_chunk,current_pos);
136
137 this->logger->log_chunk(this->logger,RAW | MOST, "Octets (Mesage + Nonce + prf(Sk_px,Idx)",&octets);
138 return octets;
139 }
140
141 /**
142 * Implementation of private_authenticator_t.allocate_auth_data_with_preshared_secret.
143 */
144 static chunk_t allocate_auth_data_with_preshared_secret (private_authenticator_t *this,chunk_t last_message, chunk_t nonce,id_payload_t *id_payload, bool initiator,chunk_t preshared_secret)
145 {
146 chunk_t key_pad = {ptr: IKE_V2_KEY_PAD, len:IKE_V2_KEY_PAD_LEN};
147 u_int8_t key_buffer[this->prf->get_block_size(this->prf)];
148 chunk_t key = {ptr: key_buffer, len: sizeof(key_buffer)};
149 chunk_t auth_data;
150
151 chunk_t octets = this->allocate_octets(this,last_message,nonce,id_payload,initiator);
152
153 /*
154 * AUTH = prf(prf(Shared Secret,"Key Pad for IKEv2"), <msg octets>)
155 */
156
157 this->prf->set_key(this->prf,preshared_secret);
158 this->prf->get_bytes(this->prf,key_pad,key_buffer);
159 this->prf->set_key(this->prf,key);
160 this->prf->allocate_bytes(this->prf,octets,&auth_data);
161 allocator_free_chunk(&octets);
162 this->logger->log_chunk(this->logger,RAW | MOST, "Authenticated data",&auth_data);
163
164 return auth_data;
165 }
166
167 /**
168 * Implementation of authenticator_t.verify_auth_data.
169 */
170 static status_t verify_auth_data (private_authenticator_t *this,auth_payload_t *auth_payload, chunk_t last_received_packet,chunk_t my_nonce,id_payload_t *other_id_payload,bool initiator,bool *verified)
171 {
172 switch(auth_payload->get_auth_method(auth_payload))
173 {
174 case SHARED_KEY_MESSAGE_INTEGRITY_CODE:
175 {
176
177 identification_t *other_id = other_id_payload->get_identification(other_id_payload);
178 chunk_t auth_data = auth_payload->get_data(auth_payload);
179 chunk_t preshared_secret;
180 status_t status;
181
182 status = charon->configuration_manager->get_shared_secret(charon->configuration_manager,other_id,&preshared_secret);
183 other_id->destroy(other_id);
184 if (status != SUCCESS)
185 {
186 return status;
187 }
188
189 chunk_t my_auth_data = this->allocate_auth_data_with_preshared_secret(this,last_received_packet,my_nonce,other_id_payload,initiator,preshared_secret);
190
191 if (auth_data.len != my_auth_data.len)
192 {
193 *verified = FALSE;
194 allocator_free_chunk(&my_auth_data);
195 return SUCCESS;
196 }
197 if (memcmp(auth_data.ptr,my_auth_data.ptr,my_auth_data.len) == 0)
198 {
199 *verified = TRUE;
200 }
201 else
202 {
203 *verified = FALSE;
204 }
205 allocator_free_chunk(&my_auth_data);
206 return SUCCESS;
207 }
208 case RSA_DIGITAL_SIGNATURE:
209 {
210 identification_t *other_id = other_id_payload->get_identification(other_id_payload);
211 rsa_public_key_t *public_key;
212 status_t status;
213 chunk_t octets, auth_data;
214
215 auth_data = auth_payload->get_data(auth_payload);
216
217 status = charon->configuration_manager->get_rsa_public_key(charon->configuration_manager, other_id, &public_key);
218 other_id->destroy(other_id);
219 if (status != SUCCESS)
220 {
221 return status;
222 }
223
224 octets = this->allocate_octets(this,last_received_packet,my_nonce,other_id_payload,initiator);
225
226 status = public_key->verify_emsa_pkcs1_signature(public_key, octets, auth_data);
227 if (status == SUCCESS)
228 {
229 *verified = TRUE;
230 }
231 else
232 {
233 *verified = FALSE;
234 }
235
236 allocator_free_chunk(&octets);
237 return status;
238 }
239 default:
240 {
241 return NOT_SUPPORTED;
242 }
243 }
244 }
245
246 /**
247 * Implementation of authenticator_t.compute_auth_data.
248 */
249 static status_t compute_auth_data (private_authenticator_t *this,auth_payload_t **auth_payload, chunk_t last_sent_packet,chunk_t other_nonce,id_payload_t *my_id_payload,bool initiator)
250 {
251 sa_config_t *sa_config = this->ike_sa->get_sa_config(this->ike_sa);
252
253 switch(sa_config->get_auth_method(sa_config))
254 {
255 case SHARED_KEY_MESSAGE_INTEGRITY_CODE:
256 {
257 identification_t *my_id =my_id_payload->get_identification(my_id_payload);
258 chunk_t preshared_secret;
259 status_t status;
260
261 status = charon->configuration_manager->get_shared_secret(charon->configuration_manager,my_id,&preshared_secret);
262
263 my_id->destroy(my_id);
264 if (status != SUCCESS)
265 {
266 return status;
267 }
268
269 chunk_t auth_data = this->allocate_auth_data_with_preshared_secret(this,last_sent_packet,other_nonce,my_id_payload,initiator,preshared_secret);
270
271 *auth_payload = auth_payload_create();
272 (*auth_payload)->set_auth_method((*auth_payload),SHARED_KEY_MESSAGE_INTEGRITY_CODE);
273 (*auth_payload)->set_data((*auth_payload),auth_data);
274
275 allocator_free_chunk(&auth_data);
276 return SUCCESS;
277 }
278 case RSA_DIGITAL_SIGNATURE:
279 {
280 identification_t *my_id = my_id_payload->get_identification(my_id_payload);
281 rsa_private_key_t *private_key;
282 status_t status;
283 chunk_t octets, auth_data;
284
285 status = charon->configuration_manager->get_rsa_private_key(charon->configuration_manager, my_id, &private_key);
286 my_id->destroy(my_id);
287 if (status != SUCCESS)
288 {
289 return status;
290 }
291
292 octets = this->allocate_octets(this,last_sent_packet,other_nonce,my_id_payload,initiator);
293
294 status = private_key->build_emsa_pkcs1_signature(private_key, HASH_SHA1, octets, &auth_data);
295 allocator_free_chunk(&octets);
296 if (status != SUCCESS)
297 {
298 return status;
299 }
300
301 *auth_payload = auth_payload_create();
302 (*auth_payload)->set_auth_method((*auth_payload), RSA_DIGITAL_SIGNATURE);
303 (*auth_payload)->set_data((*auth_payload),auth_data);
304
305 allocator_free_chunk(&auth_data);
306 return SUCCESS;
307 }
308 default:
309 {
310 return NOT_SUPPORTED;
311 }
312 }
313 }
314
315 /**
316 * Implementation of authenticator_t.destroy.
317 */
318 static void destroy (private_authenticator_t *this)
319 {
320 allocator_free(this);
321 }
322
323 /*
324 * Described in header.
325 */
326 authenticator_t *authenticator_create(protected_ike_sa_t *ike_sa)
327 {
328 private_authenticator_t *this = allocator_alloc_thing(private_authenticator_t);
329
330 /* Public functions */
331 this->public.destroy = (void(*)(authenticator_t*))destroy;
332 this->public.verify_auth_data = (status_t (*) (authenticator_t *,auth_payload_t *, chunk_t ,chunk_t ,id_payload_t *,bool,bool *)) verify_auth_data;
333 this->public.compute_auth_data = (status_t (*) (authenticator_t *,auth_payload_t **, chunk_t ,chunk_t ,id_payload_t *,bool)) compute_auth_data;
334
335 /* private functions */
336 this->allocate_octets = allocate_octets;
337 this->allocate_auth_data_with_preshared_secret = allocate_auth_data_with_preshared_secret;
338
339 /* private data */
340 this->ike_sa = ike_sa;
341 this->prf = this->ike_sa->get_prf(this->ike_sa);
342 this->logger = this->ike_sa->get_logger(this->ike_sa);
343
344 return &(this->public);
345 }