1 /******************************************************************************
2 *
3 * Copyright 1999-2012 Broadcom Corporation
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at:
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 ******************************************************************************/
18
19 /******************************************************************************
20 *
21 * This file contains security manager protocol utility functions
22 *
23 ******************************************************************************/
24 #include "bt_target.h"
25
26 #include <base/bind.h>
27 #include <string.h>
28 #include "bt_utils.h"
29 #include "btm_ble_api.h"
30 #include "btm_ble_int.h"
31 #include "device/include/controller.h"
32 #include "hcimsgs.h"
33 #include "osi/include/osi.h"
34 #include "p_256_ecc_pp.h"
35 #include "smp_int.h"
36 #include "stack/btm/btm_dev.h"
37 #include "stack/btm/btm_sec.h"
38 #include "stack/crypto_toolbox/crypto_toolbox.h"
39 #include "stack/include/acl_api.h"
40
41 #include <algorithm>
42
43 extern tBTM_CB btm_cb; // TODO Remove
44
45 using base::Bind;
46 using crypto_toolbox::aes_128;
47
48 #ifndef SMP_MAX_ENC_REPEAT
49 #define SMP_MAX_ENC_REPEAT 3
50 #endif
51
52 static void smp_process_stk(tSMP_CB* p_cb, Octet16* p);
53 static Octet16 smp_calculate_legacy_short_term_key(tSMP_CB* p_cb);
54 static void smp_process_private_key(tSMP_CB* p_cb);
55
56 #define SMP_PASSKEY_MASK 0xfff00000
57
58 // If there is data saved here, then use its info instead
59 // This needs to be cleared on a successfult pairing using the oob data
60 static tSMP_LOC_OOB_DATA saved_local_oob_data = {};
61
smp_save_local_oob_data(tSMP_CB * p_cb)62 void smp_save_local_oob_data(tSMP_CB* p_cb) {
63 saved_local_oob_data = p_cb->sc_oob_data.loc_oob_data;
64 }
65
smp_clear_local_oob_data()66 void smp_clear_local_oob_data() { saved_local_oob_data = {}; }
67
is_empty(tSMP_LOC_OOB_DATA * data)68 static bool is_empty(tSMP_LOC_OOB_DATA* data) {
69 tSMP_LOC_OOB_DATA empty_data = {};
70 return memcmp(data, &empty_data, sizeof(tSMP_LOC_OOB_DATA)) == 0;
71 }
72
smp_debug_print_nbyte_little_endian(uint8_t * p,const char * key_name,uint8_t len)73 void smp_debug_print_nbyte_little_endian(uint8_t* p, const char* key_name,
74 uint8_t len) {
75 }
76
smp_debug_print_nbyte_little_endian(const Octet16 & p,const char * key_name,uint8_t len)77 inline void smp_debug_print_nbyte_little_endian(const Octet16& p,
78 const char* key_name,
79 uint8_t len) {
80 smp_debug_print_nbyte_little_endian(const_cast<uint8_t*>(p.data()), key_name,
81 len);
82 }
83
smp_debug_print_nbyte_big_endian(uint8_t * p,const char * key_name,uint8_t len)84 void smp_debug_print_nbyte_big_endian(uint8_t* p, const char* key_name,
85 uint8_t len) {
86 }
87
88 /** This function is called to process a passkey. */
smp_proc_passkey(tSMP_CB * p_cb,BT_OCTET8 rand)89 void smp_proc_passkey(tSMP_CB* p_cb, BT_OCTET8 rand) {
90 uint8_t* tt = p_cb->tk.data();
91 uint32_t passkey; /* 19655 test number; */
92 uint8_t* pp = rand;
93
94 SMP_TRACE_DEBUG("%s", __func__);
95 STREAM_TO_UINT32(passkey, pp);
96 passkey &= ~SMP_PASSKEY_MASK;
97
98 /* truncate by maximum value */
99 while (passkey > BTM_MAX_PASSKEY_VAL) passkey >>= 1;
100
101 /* save the TK */
102 p_cb->tk = {0};
103 UINT32_TO_STREAM(tt, passkey);
104
105 if (p_cb->p_callback) {
106 tSMP_EVT_DATA smp_evt_data;
107 smp_evt_data.passkey = passkey;
108 (*p_cb->p_callback)(SMP_PASSKEY_NOTIF_EVT, p_cb->pairing_bda,
109 &smp_evt_data);
110 }
111
112 if (p_cb->selected_association_model == SMP_MODEL_SEC_CONN_PASSKEY_DISP) {
113 tSMP_INT_DATA smp_int_data;
114 smp_int_data.passkey = passkey;
115 smp_sm_event(&smp_cb, SMP_KEY_READY_EVT, &smp_int_data);
116 } else {
117 tSMP_KEY key;
118 key.key_type = SMP_KEY_TYPE_TK;
119 key.p_data = p_cb->tk.data();
120 tSMP_INT_DATA smp_int_data;
121 smp_int_data.key = key;
122 smp_sm_event(p_cb, SMP_KEY_READY_EVT, &smp_int_data);
123 }
124 }
125
126 /*******************************************************************************
127 *
128 * Function smp_generate_passkey
129 *
130 * Description This function is called to generate passkey.
131 *
132 * Returns void
133 *
134 ******************************************************************************/
smp_generate_passkey(tSMP_CB * p_cb,UNUSED_ATTR tSMP_INT_DATA * p_data)135 void smp_generate_passkey(tSMP_CB* p_cb, UNUSED_ATTR tSMP_INT_DATA* p_data) {
136 SMP_TRACE_DEBUG("%s", __func__);
137 /* generate MRand or SRand */
138 btsnd_hcic_ble_rand(Bind(&smp_proc_passkey, p_cb));
139 }
140
141 /*******************************************************************************
142 *
143 * Function smp_generate_stk
144 *
145 * Description This function is called to generate STK calculated by
146 * running AES with the TK value as key and a concatenation of
147 * the random values.
148 *
149 * Returns void
150 *
151 ******************************************************************************/
smp_generate_stk(tSMP_CB * p_cb,UNUSED_ATTR tSMP_INT_DATA * p_data)152 void smp_generate_stk(tSMP_CB* p_cb, UNUSED_ATTR tSMP_INT_DATA* p_data) {
153 Octet16 output;
154
155 SMP_TRACE_DEBUG("%s", __func__);
156
157 if (p_cb->le_secure_connections_mode_is_used) {
158 SMP_TRACE_DEBUG("FOR LE SC LTK IS USED INSTEAD OF STK");
159 output = p_cb->ltk;
160 } else {
161 output = smp_calculate_legacy_short_term_key(p_cb);
162 }
163
164 smp_process_stk(p_cb, &output);
165 }
166
167 /**
168 * This function is called to calculate CSRK
169 */
smp_compute_csrk(uint16_t div,tSMP_CB * p_cb)170 void smp_compute_csrk(uint16_t div, tSMP_CB* p_cb) {
171 uint8_t buffer[4]; /* for (r || DIV) r=1*/
172 uint16_t r = 1;
173 uint8_t* p = buffer;
174
175 p_cb->div = div;
176
177 SMP_TRACE_DEBUG("%s: div=%x", __func__, p_cb->div);
178 const Octet16& er = BTM_GetDeviceEncRoot();
179 /* CSRK = d1(ER, DIV, 1) */
180 UINT16_TO_STREAM(p, p_cb->div);
181 UINT16_TO_STREAM(p, r);
182
183 p_cb->csrk = aes_128(er, buffer, 4);
184 smp_send_csrk_info(p_cb, NULL);
185 }
186
187 /**
188 * This function is called to calculate CSRK, starting with DIV generation.
189 */
smp_generate_csrk(tSMP_CB * p_cb,UNUSED_ATTR tSMP_INT_DATA * p_data)190 void smp_generate_csrk(tSMP_CB* p_cb, UNUSED_ATTR tSMP_INT_DATA* p_data) {
191 bool div_status;
192
193 SMP_TRACE_DEBUG("smp_generate_csrk");
194
195 div_status = btm_get_local_div(p_cb->pairing_bda, &p_cb->div);
196 if (div_status) {
197 smp_compute_csrk(p_cb->div, p_cb);
198 } else {
199 SMP_TRACE_DEBUG("Generate DIV for CSRK");
200 btsnd_hcic_ble_rand(Bind(
201 [](tSMP_CB* p_cb, BT_OCTET8 rand) {
202 uint16_t div;
203 STREAM_TO_UINT16(div, rand);
204 smp_compute_csrk(div, p_cb);
205 },
206 p_cb));
207 }
208 }
209
210 /*******************************************************************************
211 * Function smp_concatenate_peer - LSB first
212 * add pairing command sent from local device into p1.
213 ******************************************************************************/
smp_concatenate_local(tSMP_CB * p_cb,uint8_t ** p_data,uint8_t op_code)214 void smp_concatenate_local(tSMP_CB* p_cb, uint8_t** p_data, uint8_t op_code) {
215 uint8_t* p = *p_data;
216
217 SMP_TRACE_DEBUG("%s", __func__);
218 UINT8_TO_STREAM(p, op_code);
219 UINT8_TO_STREAM(p, p_cb->local_io_capability);
220 UINT8_TO_STREAM(p, p_cb->loc_oob_flag);
221 UINT8_TO_STREAM(p, p_cb->loc_auth_req);
222 UINT8_TO_STREAM(p, p_cb->loc_enc_size);
223 UINT8_TO_STREAM(p, p_cb->local_i_key);
224 UINT8_TO_STREAM(p, p_cb->local_r_key);
225
226 *p_data = p;
227 }
228
229 /*******************************************************************************
230 * Function smp_concatenate_peer - LSB first
231 * add pairing command received from peer device into p1.
232 ******************************************************************************/
smp_concatenate_peer(tSMP_CB * p_cb,uint8_t ** p_data,uint8_t op_code)233 void smp_concatenate_peer(tSMP_CB* p_cb, uint8_t** p_data, uint8_t op_code) {
234 uint8_t* p = *p_data;
235
236 SMP_TRACE_DEBUG("smp_concatenate_peer ");
237 UINT8_TO_STREAM(p, op_code);
238 UINT8_TO_STREAM(p, p_cb->peer_io_caps);
239 UINT8_TO_STREAM(p, p_cb->peer_oob_flag);
240 UINT8_TO_STREAM(p, p_cb->peer_auth_req);
241 UINT8_TO_STREAM(p, p_cb->peer_enc_size);
242 UINT8_TO_STREAM(p, p_cb->peer_i_key);
243 UINT8_TO_STREAM(p, p_cb->peer_r_key);
244
245 *p_data = p;
246 }
247
248 /** Generate Confirm/Compare Step1:
249 * p1 = (MSB) pres || preq || rat' || iat' (LSB)
250 * Fill in values LSB first thus
251 * p1 = iat' || rat' || preq || pres
252 */
smp_gen_p1_4_confirm(tSMP_CB * p_cb,tBLE_ADDR_TYPE remote_bd_addr_type)253 Octet16 smp_gen_p1_4_confirm(tSMP_CB* p_cb,
254 tBLE_ADDR_TYPE remote_bd_addr_type) {
255 SMP_TRACE_DEBUG("%s", __func__);
256 Octet16 p1;
257 uint8_t* p = p1.data();
258 if (p_cb->role == HCI_ROLE_CENTRAL) {
259 /* iat': initiator's (local) address type */
260 UINT8_TO_STREAM(p, p_cb->addr_type);
261 /* rat': responder's (remote) address type */
262 UINT8_TO_STREAM(p, remote_bd_addr_type);
263 /* preq : Pairing Request (local) command */
264 smp_concatenate_local(p_cb, &p, SMP_OPCODE_PAIRING_REQ);
265 /* pres : Pairing Response (remote) command */
266 smp_concatenate_peer(p_cb, &p, SMP_OPCODE_PAIRING_RSP);
267 } else {
268 /* iat': initiator's (remote) address type */
269 UINT8_TO_STREAM(p, remote_bd_addr_type);
270 /* rat': responder's (local) address type */
271 UINT8_TO_STREAM(p, p_cb->addr_type);
272 /* preq : Pairing Request (remote) command */
273 smp_concatenate_peer(p_cb, &p, SMP_OPCODE_PAIRING_REQ);
274 /* pres : Pairing Response (local) command */
275 smp_concatenate_local(p_cb, &p, SMP_OPCODE_PAIRING_RSP);
276 }
277 smp_debug_print_nbyte_little_endian(p1, "p1 = iat' || rat' || preq || pres",
278 16);
279
280 return p1;
281 }
282
283 /** Generate Confirm/Compare Step2:
284 * p2 = (MSB) padding || ia || ra (LSB)
285 * Fill values LSB first and thus:
286 * p2 = ra || ia || padding
287 */
smp_gen_p2_4_confirm(tSMP_CB * p_cb,const RawAddress & remote_bda)288 Octet16 smp_gen_p2_4_confirm(tSMP_CB* p_cb, const RawAddress& remote_bda) {
289 SMP_TRACE_DEBUG("%s", __func__);
290 Octet16 p2{0};
291 uint8_t* p = p2.data();
292 /* 32-bit Padding */
293 memset(p, 0, OCTET16_LEN);
294 if (p_cb->role == HCI_ROLE_CENTRAL) {
295 /* ra : Responder's (remote) address */
296 BDADDR_TO_STREAM(p, remote_bda);
297 /* ia : Initiator's (local) address */
298 BDADDR_TO_STREAM(p, p_cb->local_bda);
299 } else {
300 /* ra : Responder's (local) address */
301 BDADDR_TO_STREAM(p, p_cb->local_bda);
302 /* ia : Initiator's (remote) address */
303 BDADDR_TO_STREAM(p, remote_bda);
304 }
305 smp_debug_print_nbyte_little_endian(p2, "p2 = ra || ia || padding", 16);
306 return p2;
307 }
308
309 /*******************************************************************************
310 *
311 * Function smp_calculate_comfirm
312 *
313 * Description This function (c1) is called to calculate Confirm value.
314 *
315 * Returns tSMP_STATUS status of confirmation calculation
316 *
317 ******************************************************************************/
smp_calculate_comfirm(tSMP_CB * p_cb,const Octet16 & rand,Octet16 * output)318 tSMP_STATUS smp_calculate_comfirm(tSMP_CB* p_cb, const Octet16& rand,
319 Octet16* output) {
320 SMP_TRACE_DEBUG("%s", __func__);
321 RawAddress remote_bda;
322 tBLE_ADDR_TYPE remote_bd_addr_type = BLE_ADDR_PUBLIC;
323 /* get remote connection specific bluetooth address */
324 if (!BTM_ReadRemoteConnectionAddr(p_cb->pairing_bda, remote_bda,
325 &remote_bd_addr_type)) {
326 SMP_TRACE_ERROR("%s: cannot obtain remote device address", __func__);
327 return SMP_PAIR_FAIL_UNKNOWN;
328 }
329 /* get local connection specific bluetooth address */
330 BTM_ReadConnectionAddr(p_cb->pairing_bda, p_cb->local_bda, &p_cb->addr_type);
331 /* generate p1 = pres || preq || rat' || iat' */
332 Octet16 p1 = smp_gen_p1_4_confirm(p_cb, remote_bd_addr_type);
333 /* p1' = rand XOR p1 */
334 smp_xor_128(&p1, rand);
335 smp_debug_print_nbyte_little_endian(p1, "p1' = p1 XOR r", 16);
336 /* calculate e1 = e(k, p1'), where k = TK */
337 smp_debug_print_nbyte_little_endian(p_cb->tk.data(), "TK", 16);
338 Octet16 e1 = aes_128(p_cb->tk, p1);
339 smp_debug_print_nbyte_little_endian(e1.data(), "e1 = e(k, p1')", 16);
340 /* generate p2 = padding || ia || ra */
341 Octet16 p2 = smp_gen_p2_4_confirm(p_cb, remote_bda);
342 /* calculate p2' = (p2 XOR e1) */
343 smp_xor_128(&p2, e1);
344 smp_debug_print_nbyte_little_endian(p2, "p2' = p2 XOR e1", 16);
345 /* calculate: c1 = e(k, p2') */
346 *output = aes_128(p_cb->tk, p2);
347 return SMP_SUCCESS;
348 }
349
350 /*******************************************************************************
351 *
352 * Function smp_generate_confirm
353 *
354 * Description This function is called when random number (MRand or SRand)
355 * is generated by the controller and the stack needs to
356 * calculate c1 value (MConfirm or SConfirm) for the first time
357 *
358 * Returns void
359 *
360 ******************************************************************************/
smp_generate_confirm(tSMP_CB * p_cb)361 static void smp_generate_confirm(tSMP_CB* p_cb) {
362 SMP_TRACE_DEBUG("%s", __func__);
363 smp_debug_print_nbyte_little_endian(p_cb->rand.data(), "local_rand", 16);
364 Octet16 output;
365 tSMP_STATUS status = smp_calculate_comfirm(p_cb, p_cb->rand, &output);
366 if (status != SMP_SUCCESS) {
367 tSMP_INT_DATA smp_int_data;
368 smp_int_data.status = status;
369 smp_sm_event(p_cb, SMP_AUTH_CMPL_EVT, &smp_int_data);
370 return;
371 }
372 tSMP_KEY key;
373 p_cb->confirm = output;
374 smp_debug_print_nbyte_little_endian(p_cb->confirm, "Local Confirm generated",
375 16);
376 key.key_type = SMP_KEY_TYPE_CFM;
377 key.p_data = output.data();
378 tSMP_INT_DATA smp_int_data;
379 smp_int_data.key = key;
380 smp_sm_event(p_cb, SMP_KEY_READY_EVT, &smp_int_data);
381 }
382
383 /*******************************************************************************
384 *
385 * Function smp_generate_srand_mrand_confirm
386 *
387 * Description This function is called to start the second pairing phase by
388 * start generating random number.
389 *
390 *
391 * Returns void
392 *
393 ******************************************************************************/
smp_generate_srand_mrand_confirm(tSMP_CB * p_cb,UNUSED_ATTR tSMP_INT_DATA * p_data)394 void smp_generate_srand_mrand_confirm(tSMP_CB* p_cb,
395 UNUSED_ATTR tSMP_INT_DATA* p_data) {
396 SMP_TRACE_DEBUG("%s", __func__);
397 /* generate MRand or SRand */
398 btsnd_hcic_ble_rand(Bind(
399 [](tSMP_CB* p_cb, BT_OCTET8 rand) {
400 memcpy(p_cb->rand.data(), rand, 8);
401
402 /* generate 64 MSB of MRand or SRand */
403 btsnd_hcic_ble_rand(Bind(
404 [](tSMP_CB* p_cb, BT_OCTET8 rand) {
405 memcpy((void*)&p_cb->rand[8], rand, BT_OCTET8_LEN);
406 smp_generate_confirm(p_cb);
407 },
408 p_cb));
409 },
410 p_cb));
411 }
412
413 /*******************************************************************************
414 *
415 * Function smp_generate_compare
416 *
417 * Description This function is called when random number (MRand or SRand)
418 * is received from remote device and the c1 value (MConfirm
419 * or SConfirm) needs to be generated to authenticate remote
420 * device.
421 *
422 * Returns void
423 *
424 ******************************************************************************/
smp_generate_compare(tSMP_CB * p_cb,UNUSED_ATTR tSMP_INT_DATA * p_data)425 void smp_generate_compare(tSMP_CB* p_cb, UNUSED_ATTR tSMP_INT_DATA* p_data) {
426 SMP_TRACE_DEBUG("smp_generate_compare ");
427 smp_debug_print_nbyte_little_endian(p_cb->rrand, "peer rand", 16);
428 Octet16 output;
429 tSMP_STATUS status = smp_calculate_comfirm(p_cb, p_cb->rrand, &output);
430 if (status != SMP_SUCCESS) {
431 tSMP_INT_DATA smp_int_data;
432 smp_int_data.status = status;
433 smp_sm_event(p_cb, SMP_AUTH_CMPL_EVT, &smp_int_data);
434 return;
435 }
436 tSMP_KEY key;
437 smp_debug_print_nbyte_little_endian(output.data(), "Remote Confirm generated",
438 16);
439 key.key_type = SMP_KEY_TYPE_CMP;
440 key.p_data = output.data();
441 tSMP_INT_DATA smp_int_data;
442 smp_int_data.key = key;
443 smp_sm_event(p_cb, SMP_KEY_READY_EVT, &smp_int_data);
444 }
445
446 /** This function is called when STK is generated proceed to send the encrypt
447 * the link using STK. */
smp_process_stk(tSMP_CB * p_cb,Octet16 * p)448 static void smp_process_stk(tSMP_CB* p_cb, Octet16* p) {
449 tSMP_KEY key;
450
451 SMP_TRACE_DEBUG("smp_process_stk ");
452 smp_mask_enc_key(p_cb->loc_enc_size, p);
453
454 key.key_type = SMP_KEY_TYPE_STK;
455 key.p_data = p->data();
456
457 tSMP_INT_DATA smp_int_data;
458 smp_int_data.key = key;
459 smp_sm_event(p_cb, SMP_KEY_READY_EVT, &smp_int_data);
460 }
461
462 /** This function calculates EDIV = Y xor DIV */
smp_process_ediv(tSMP_CB * p_cb,Octet16 & p)463 static void smp_process_ediv(tSMP_CB* p_cb, Octet16& p) {
464 tSMP_KEY key;
465 uint8_t* pp = p.data();
466 uint16_t y;
467
468 SMP_TRACE_DEBUG("smp_process_ediv ");
469 STREAM_TO_UINT16(y, pp);
470
471 /* EDIV = Y xor DIV */
472 p_cb->ediv = p_cb->div ^ y;
473 /* send LTK ready */
474 SMP_TRACE_ERROR("LTK ready");
475 key.key_type = SMP_KEY_TYPE_LTK;
476 key.p_data = p.data();
477
478 tSMP_INT_DATA smp_int_data;
479 smp_int_data.key = key;
480 smp_sm_event(p_cb, SMP_KEY_READY_EVT, &smp_int_data);
481 }
482
483 /**
484 * This function is to proceed generate Y = E(DHK, Rand)
485 */
smp_generate_y(tSMP_CB * p_cb,BT_OCTET8 rand)486 static void smp_generate_y(tSMP_CB* p_cb, BT_OCTET8 rand) {
487 SMP_TRACE_DEBUG("%s ", __func__);
488
489 const Octet16& dhk = BTM_GetDeviceDHK();
490
491 memcpy(p_cb->enc_rand, rand, BT_OCTET8_LEN);
492 Octet16 output = aes_128(dhk, rand, BT_OCTET8_LEN);
493 smp_process_ediv(p_cb, output);
494 }
495
496 /**
497 * Calculate LTK = d1(ER, DIV, 0)= e(ER, DIV)
498 */
smp_generate_ltk_cont(uint16_t div,tSMP_CB * p_cb)499 static void smp_generate_ltk_cont(uint16_t div, tSMP_CB* p_cb) {
500 p_cb->div = div;
501
502 SMP_TRACE_DEBUG("%s", __func__);
503 const Octet16& er = BTM_GetDeviceEncRoot();
504
505 /* LTK = d1(ER, DIV, 0)= e(ER, DIV)*/
506 Octet16 ltk = aes_128(er, (uint8_t*)&p_cb->div, sizeof(uint16_t));
507 /* mask the LTK */
508 smp_mask_enc_key(p_cb->loc_enc_size, <k);
509 p_cb->ltk = ltk;
510
511 /* generate EDIV and rand now */
512 btsnd_hcic_ble_rand(Bind(&smp_generate_y, p_cb));
513 }
514
515 /*******************************************************************************
516 *
517 * Function smp_generate_ltk
518 *
519 * Description This function is called:
520 * - in legacy pairing - to calculate LTK, starting with DIV
521 * generation;
522 * - in LE Secure Connections pairing over LE transport - to
523 * process LTK already generated to encrypt LE link;
524 * - in LE Secure Connections pairing over BR/EDR transport -
525 * to start BR/EDR Link Key processing.
526 *
527 * Returns void
528 *
529 ******************************************************************************/
smp_generate_ltk(tSMP_CB * p_cb,UNUSED_ATTR tSMP_INT_DATA * p_data)530 void smp_generate_ltk(tSMP_CB* p_cb, UNUSED_ATTR tSMP_INT_DATA* p_data) {
531 SMP_TRACE_DEBUG("%s", __func__);
532
533 if (smp_get_br_state() == SMP_BR_STATE_BOND_PENDING) {
534 smp_br_process_link_key(p_cb, NULL);
535 return;
536 } else if (p_cb->le_secure_connections_mode_is_used) {
537 smp_process_secure_connection_long_term_key();
538 return;
539 }
540
541 bool div_status = btm_get_local_div(p_cb->pairing_bda, &p_cb->div);
542
543 if (div_status) {
544 smp_generate_ltk_cont(p_cb->div, p_cb);
545 } else {
546 SMP_TRACE_DEBUG("%s: Generate DIV for LTK", __func__);
547
548 /* generate MRand or SRand */
549 btsnd_hcic_ble_rand(Bind(
550 [](tSMP_CB* p_cb, BT_OCTET8 rand) {
551 uint16_t div;
552 STREAM_TO_UINT16(div, rand);
553 smp_generate_ltk_cont(div, p_cb);
554 },
555 p_cb));
556 }
557 }
558
559 /* The function calculates legacy STK */
smp_calculate_legacy_short_term_key(tSMP_CB * p_cb)560 Octet16 smp_calculate_legacy_short_term_key(tSMP_CB* p_cb) {
561 SMP_TRACE_DEBUG("%s", __func__);
562
563 Octet16 text{0};
564 if (p_cb->role == HCI_ROLE_CENTRAL) {
565 memcpy(text.data(), p_cb->rand.data(), BT_OCTET8_LEN);
566 memcpy(text.data() + BT_OCTET8_LEN, p_cb->rrand.data(), BT_OCTET8_LEN);
567 } else {
568 memcpy(text.data(), p_cb->rrand.data(), BT_OCTET8_LEN);
569 memcpy(text.data() + BT_OCTET8_LEN, p_cb->rand.data(), BT_OCTET8_LEN);
570 }
571
572 /* generate STK = Etk(rand|rrand)*/
573 return aes_128(p_cb->tk, text);
574 }
575
576 /*******************************************************************************
577 *
578 * Function smp_create_private_key
579 *
580 * Description This function is called to create private key used to
581 * calculate public key and DHKey.
582 * The function starts private key creation requesting
583 * for the controller to generate [0-7] octets of private key.
584 *
585 * Returns void
586 *
587 ******************************************************************************/
smp_create_private_key(tSMP_CB * p_cb,tSMP_INT_DATA * p_data)588 void smp_create_private_key(tSMP_CB* p_cb, tSMP_INT_DATA* p_data) {
589 SMP_TRACE_DEBUG("%s", __func__);
590
591 // Only use the stored OOB data if we are in an oob association model
592 if (p_cb->selected_association_model == SMP_MODEL_SEC_CONN_OOB) {
593 LOG_WARN("OOB Association Model");
594 // Make sure our data isn't empty, otherwise we generate new and eventually
595 // pairing will fail Not much we can do about it at this point, just have to
596 // generate new data The data will be cleared after the advertiser times
597 // out, so if the advertiser times out we want the pairing to fail anyway.
598 if (!is_empty(&saved_local_oob_data)) {
599 LOG_WARN("Found OOB data, loading keys");
600 for (int i = 0; i < BT_OCTET32_LEN; i++) {
601 p_cb->private_key[i] = saved_local_oob_data.private_key_used[i];
602 p_cb->loc_publ_key.x[i] = saved_local_oob_data.publ_key_used.x[i];
603 p_cb->loc_publ_key.y[i] = saved_local_oob_data.publ_key_used.y[i];
604 }
605 p_cb->sc_oob_data.loc_oob_data = saved_local_oob_data;
606 p_cb->local_random = saved_local_oob_data.randomizer;
607 smp_process_private_key(p_cb);
608 return;
609 }
610 LOG_WARN("OOB Association Model with no saved data present");
611 }
612
613 btsnd_hcic_ble_rand(Bind(
614 [](tSMP_CB* p_cb, BT_OCTET8 rand) {
615 memcpy((void*)p_cb->private_key, rand, BT_OCTET8_LEN);
616 btsnd_hcic_ble_rand(Bind(
617 [](tSMP_CB* p_cb, BT_OCTET8 rand) {
618 memcpy((void*)&p_cb->private_key[8], rand, BT_OCTET8_LEN);
619 btsnd_hcic_ble_rand(Bind(
620 [](tSMP_CB* p_cb, BT_OCTET8 rand) {
621 memcpy((void*)&p_cb->private_key[16], rand, BT_OCTET8_LEN);
622 btsnd_hcic_ble_rand(Bind(
623 [](tSMP_CB* p_cb, BT_OCTET8 rand) {
624 memcpy((void*)&p_cb->private_key[24], rand,
625 BT_OCTET8_LEN);
626 smp_process_private_key(p_cb);
627 },
628 p_cb));
629 },
630 p_cb));
631 },
632 p_cb));
633 },
634 p_cb));
635 }
636
637 /*******************************************************************************
638 *
639 * Function smp_use_oob_private_key
640 *
641 * Description This function is called
642 * - to save the secret key used to calculate the public key
643 * used in calculations of commitment sent OOB to a peer
644 * - to use this secret key to recalculate the public key and
645 * start the process of sending this public key to the peer
646 * if secret/public keys have to be reused.
647 * If the keys aren't supposed to be reused, continue from the
648 * point from which request for OOB data was issued.
649 *
650 * Returns void
651 *
652 ******************************************************************************/
smp_use_oob_private_key(tSMP_CB * p_cb,tSMP_INT_DATA * p_data)653 void smp_use_oob_private_key(tSMP_CB* p_cb, tSMP_INT_DATA* p_data) {
654 LOG_INFO("req_oob_type: %d, role: %d", p_cb->req_oob_type, p_cb->role);
655
656 switch (p_cb->req_oob_type) {
657 case SMP_OOB_BOTH:
658 case SMP_OOB_LOCAL:
659 LOG_INFO("restore secret key");
660 memcpy(p_cb->private_key, p_cb->sc_oob_data.loc_oob_data.private_key_used,
661 BT_OCTET32_LEN);
662 smp_process_private_key(p_cb);
663 break;
664 default:
665 LOG_INFO("create secret key anew");
666 smp_set_state(SMP_STATE_PAIR_REQ_RSP);
667 smp_decide_association_model(p_cb, NULL);
668 break;
669 }
670 }
671
672 /*******************************************************************************
673 *
674 * Function smp_process_private_key
675 *
676 * Description This function processes private key.
677 * It calculates public key and notifies SM that private key /
678 * public key pair is created.
679 *
680 * Returns void
681 *
682 ******************************************************************************/
smp_process_private_key(tSMP_CB * p_cb)683 void smp_process_private_key(tSMP_CB* p_cb) {
684 Point public_key;
685 BT_OCTET32 private_key;
686
687 SMP_TRACE_DEBUG("%s", __func__);
688
689 memcpy(private_key, p_cb->private_key, BT_OCTET32_LEN);
690 ECC_PointMult(&public_key, &(curve_p256.G), (uint32_t*)private_key);
691 memcpy(p_cb->loc_publ_key.x, public_key.x, BT_OCTET32_LEN);
692 memcpy(p_cb->loc_publ_key.y, public_key.y, BT_OCTET32_LEN);
693
694 smp_debug_print_nbyte_little_endian(p_cb->private_key, "private",
695 BT_OCTET32_LEN);
696 smp_debug_print_nbyte_little_endian(p_cb->loc_publ_key.x, "local public(x)",
697 BT_OCTET32_LEN);
698 smp_debug_print_nbyte_little_endian(p_cb->loc_publ_key.y, "local public(y)",
699 BT_OCTET32_LEN);
700 p_cb->flags |= SMP_PAIR_FLAG_HAVE_LOCAL_PUBL_KEY;
701 smp_sm_event(p_cb, SMP_LOC_PUBL_KEY_CRTD_EVT, NULL);
702 }
703
704 /*******************************************************************************
705 *
706 * Function smp_compute_dhkey
707 *
708 * Description The function:
709 * - calculates a new public key using as input local private
710 * key and peer public key;
711 * - saves the new public key x-coordinate as DHKey.
712 *
713 * Returns void
714 *
715 ******************************************************************************/
smp_compute_dhkey(tSMP_CB * p_cb)716 void smp_compute_dhkey(tSMP_CB* p_cb) {
717 Point peer_publ_key, new_publ_key;
718 BT_OCTET32 private_key;
719
720 SMP_TRACE_DEBUG("%s", __func__);
721
722 memcpy(private_key, p_cb->private_key, BT_OCTET32_LEN);
723 memcpy(peer_publ_key.x, p_cb->peer_publ_key.x, BT_OCTET32_LEN);
724 memcpy(peer_publ_key.y, p_cb->peer_publ_key.y, BT_OCTET32_LEN);
725
726 ECC_PointMult(&new_publ_key, &peer_publ_key, (uint32_t*)private_key);
727
728 memcpy(p_cb->dhkey, new_publ_key.x, BT_OCTET32_LEN);
729
730 smp_debug_print_nbyte_little_endian(p_cb->dhkey, "Old DHKey", BT_OCTET32_LEN);
731
732 smp_debug_print_nbyte_little_endian(p_cb->private_key, "private",
733 BT_OCTET32_LEN);
734 smp_debug_print_nbyte_little_endian(p_cb->peer_publ_key.x, "rem public(x)",
735 BT_OCTET32_LEN);
736 smp_debug_print_nbyte_little_endian(p_cb->peer_publ_key.y, "rem public(y)",
737 BT_OCTET32_LEN);
738 smp_debug_print_nbyte_little_endian(p_cb->dhkey, "Reverted DHKey",
739 BT_OCTET32_LEN);
740 }
741
742 /** The function calculates and saves local commmitment in CB. */
smp_calculate_local_commitment(tSMP_CB * p_cb)743 void smp_calculate_local_commitment(tSMP_CB* p_cb) {
744 uint8_t random_input;
745
746 SMP_TRACE_DEBUG("%s", __func__);
747
748 switch (p_cb->selected_association_model) {
749 case SMP_MODEL_SEC_CONN_JUSTWORKS:
750 case SMP_MODEL_SEC_CONN_NUM_COMP:
751 if (p_cb->role == HCI_ROLE_CENTRAL)
752 SMP_TRACE_WARNING(
753 "local commitment calc on central is not expected "
754 "for Just Works/Numeric Comparison models");
755 p_cb->commitment = crypto_toolbox::f4(
756 p_cb->loc_publ_key.x, p_cb->peer_publ_key.x, p_cb->rand, 0);
757 break;
758 case SMP_MODEL_SEC_CONN_PASSKEY_ENT:
759 case SMP_MODEL_SEC_CONN_PASSKEY_DISP:
760 random_input =
761 smp_calculate_random_input(p_cb->local_random.data(), p_cb->round);
762 p_cb->commitment =
763 crypto_toolbox::f4(p_cb->loc_publ_key.x, p_cb->peer_publ_key.x,
764 p_cb->rand, random_input);
765 break;
766 case SMP_MODEL_SEC_CONN_OOB:
767 SMP_TRACE_WARNING(
768 "local commitment calc is expected for OOB model BEFORE pairing");
769 p_cb->commitment = crypto_toolbox::f4(
770 p_cb->loc_publ_key.x, p_cb->loc_publ_key.x, p_cb->local_random, 0);
771 break;
772 default:
773 SMP_TRACE_ERROR("Association Model = %d is not used in LE SC",
774 p_cb->selected_association_model);
775 return;
776 }
777
778 SMP_TRACE_EVENT("local commitment calculation is completed");
779 }
780
781 /** The function calculates peer commmitment */
smp_calculate_peer_commitment(tSMP_CB * p_cb)782 Octet16 smp_calculate_peer_commitment(tSMP_CB* p_cb) {
783 uint8_t ri;
784
785 SMP_TRACE_DEBUG("%s", __func__);
786 Octet16 output;
787 switch (p_cb->selected_association_model) {
788 case SMP_MODEL_SEC_CONN_JUSTWORKS:
789 case SMP_MODEL_SEC_CONN_NUM_COMP:
790 if (p_cb->role == HCI_ROLE_PERIPHERAL)
791 SMP_TRACE_WARNING(
792 "peer commitment calc on peripheral is not expected "
793 "for Just Works/Numeric Comparison models");
794 output = crypto_toolbox::f4(p_cb->peer_publ_key.x, p_cb->loc_publ_key.x,
795 p_cb->rrand, 0);
796 break;
797 case SMP_MODEL_SEC_CONN_PASSKEY_ENT:
798 case SMP_MODEL_SEC_CONN_PASSKEY_DISP:
799 ri = smp_calculate_random_input(p_cb->peer_random.data(), p_cb->round);
800 output = crypto_toolbox::f4(p_cb->peer_publ_key.x, p_cb->loc_publ_key.x,
801 p_cb->rrand, ri);
802 break;
803 case SMP_MODEL_SEC_CONN_OOB:
804 output = crypto_toolbox::f4(p_cb->peer_publ_key.x, p_cb->peer_publ_key.x,
805 p_cb->peer_random, 0);
806 break;
807 default:
808 SMP_TRACE_ERROR("Association Model = %d is not used in LE SC",
809 p_cb->selected_association_model);
810 return output;
811 }
812
813 SMP_TRACE_EVENT("peer commitment calculation is completed");
814 return output;
815 }
816
817 /*******************************************************************************
818 *
819 * Function smp_calculate_numeric_comparison_display_number
820 *
821 * Description The function calculates and saves number to display in
822 * numeric comparison association mode.
823 *
824 * Returns void
825 *
826 ******************************************************************************/
smp_calculate_numeric_comparison_display_number(tSMP_CB * p_cb,tSMP_INT_DATA * p_data)827 void smp_calculate_numeric_comparison_display_number(tSMP_CB* p_cb,
828 tSMP_INT_DATA* p_data) {
829 SMP_TRACE_DEBUG("%s", __func__);
830
831 if (p_cb->role == HCI_ROLE_CENTRAL) {
832 p_cb->number_to_display = crypto_toolbox::g2(
833 p_cb->loc_publ_key.x, p_cb->peer_publ_key.x, p_cb->rand, p_cb->rrand);
834 } else {
835 p_cb->number_to_display = crypto_toolbox::g2(
836 p_cb->peer_publ_key.x, p_cb->loc_publ_key.x, p_cb->rrand, p_cb->rand);
837 }
838
839 if (p_cb->number_to_display >= (BTM_MAX_PASSKEY_VAL + 1)) {
840 tSMP_INT_DATA smp_int_data;
841 smp_int_data.status = SMP_PAIR_FAIL_UNKNOWN;
842 p_cb->failure = SMP_PAIR_FAIL_UNKNOWN;
843 smp_sm_event(p_cb, SMP_AUTH_CMPL_EVT, &smp_int_data);
844 return;
845 }
846
847 SMP_TRACE_EVENT("Number to display in numeric comparison = %d",
848 p_cb->number_to_display);
849 p_cb->cb_evt = SMP_NC_REQ_EVT;
850 tSMP_INT_DATA smp_int_data;
851 smp_int_data.passkey = p_cb->number_to_display;
852 smp_sm_event(p_cb, SMP_SC_DSPL_NC_EVT, &smp_int_data);
853 return;
854 }
855
856
857 /*******************************************************************************
858 *
859 * Function smp_calculate_local_dhkey_check
860 *
861 * Description The function calculates and saves local device DHKey check
862 * value in CB.
863 * Before doing this it calls
864 * smp_calculate_f5_mackey_and_long_term_key(...).
865 * to calculate MacKey and LTK.
866 * MacKey is used in dhkey calculation.
867 *
868 * Returns void
869 *
870 ******************************************************************************/
smp_calculate_local_dhkey_check(tSMP_CB * p_cb,tSMP_INT_DATA * p_data)871 void smp_calculate_local_dhkey_check(tSMP_CB* p_cb, tSMP_INT_DATA* p_data) {
872 uint8_t iocap[3], a[7], b[7];
873
874 SMP_TRACE_DEBUG("%s", __func__);
875
876 smp_calculate_f5_mackey_and_long_term_key(p_cb);
877
878 smp_collect_local_io_capabilities(iocap, p_cb);
879
880 smp_collect_local_ble_address(a, p_cb);
881 smp_collect_peer_ble_address(b, p_cb);
882 p_cb->dhkey_check = crypto_toolbox::f6(p_cb->mac_key, p_cb->rand, p_cb->rrand,
883 p_cb->peer_random, iocap, a, b);
884
885 SMP_TRACE_EVENT("local DHKey check calculation is completed");
886 }
887
888 /*******************************************************************************
889 *
890 * Function smp_calculate_peer_dhkey_check
891 *
892 * Description The function calculates peer device DHKey check value.
893 *
894 * Returns void
895 *
896 ******************************************************************************/
smp_calculate_peer_dhkey_check(tSMP_CB * p_cb,tSMP_INT_DATA * p_data)897 void smp_calculate_peer_dhkey_check(tSMP_CB* p_cb, tSMP_INT_DATA* p_data) {
898 uint8_t iocap[3], a[7], b[7];
899 tSMP_KEY key;
900
901 SMP_TRACE_DEBUG("%s", __func__);
902
903 smp_collect_peer_io_capabilities(iocap, p_cb);
904
905 smp_collect_local_ble_address(a, p_cb);
906 smp_collect_peer_ble_address(b, p_cb);
907 Octet16 param_buf = crypto_toolbox::f6(p_cb->mac_key, p_cb->rrand, p_cb->rand,
908 p_cb->local_random, iocap, b, a);
909
910 SMP_TRACE_EVENT("peer DHKey check calculation is completed");
911 key.key_type = SMP_KEY_TYPE_PEER_DHK_CHCK;
912 key.p_data = param_buf.data();
913 tSMP_INT_DATA smp_int_data;
914 smp_int_data.key = key;
915 smp_sm_event(p_cb, SMP_SC_KEY_READY_EVT, &smp_int_data);
916 }
917
918
919 /*******************************************************************************
920 *
921 * Function smp_calculate_link_key_from_long_term_key
922 *
923 * Description The function calculates and saves BR/EDR link key derived
924 * from LE SC LTK.
925 *
926 * Returns false if out of resources, true in other cases.
927 *
928 ******************************************************************************/
smp_calculate_link_key_from_long_term_key(tSMP_CB * p_cb)929 bool smp_calculate_link_key_from_long_term_key(tSMP_CB* p_cb) {
930 tBTM_SEC_DEV_REC* p_dev_rec;
931 RawAddress bda_for_lk;
932 tBLE_ADDR_TYPE conn_addr_type;
933
934 SMP_TRACE_DEBUG("%s", __func__);
935
936 if (p_cb->id_addr_rcvd && p_cb->id_addr_type == BLE_ADDR_PUBLIC) {
937 SMP_TRACE_DEBUG(
938 "Use rcvd identity address as BD_ADDR of LK rcvd identity address");
939 bda_for_lk = p_cb->id_addr;
940 } else if ((BTM_ReadRemoteConnectionAddr(p_cb->pairing_bda, bda_for_lk,
941 &conn_addr_type)) &&
942 conn_addr_type == BLE_ADDR_PUBLIC) {
943 SMP_TRACE_DEBUG("Use rcvd connection address as BD_ADDR of LK");
944 } else {
945 SMP_TRACE_WARNING("Don't have peer public address to associate with LK");
946 return false;
947 }
948
949 p_dev_rec = btm_find_dev(p_cb->pairing_bda);
950 if (p_dev_rec == NULL) {
951 SMP_TRACE_ERROR("%s failed to find Security Record", __func__);
952 return false;
953 }
954
955 Octet16 link_key =
956 crypto_toolbox::ltk_to_link_key(p_cb->ltk, p_cb->key_derivation_h7_used);
957
958 uint8_t link_key_type;
959 if (btm_cb.security_mode == BTM_SEC_MODE_SC) {
960 /* Secure Connections Only Mode */
961 link_key_type = BTM_LKEY_TYPE_AUTH_COMB_P_256;
962 } else if (controller_get_interface()->supports_secure_connections()) {
963 /* both transports are SC capable */
964 if (p_cb->sec_level == SMP_SEC_AUTHENTICATED)
965 link_key_type = BTM_LKEY_TYPE_AUTH_COMB_P_256;
966 else
967 link_key_type = BTM_LKEY_TYPE_UNAUTH_COMB_P_256;
968 } else if (btm_cb.security_mode == BTM_SEC_MODE_SP) {
969 /* BR/EDR transport is SSP capable */
970 if (p_cb->sec_level == SMP_SEC_AUTHENTICATED)
971 link_key_type = BTM_LKEY_TYPE_AUTH_COMB;
972 else
973 link_key_type = BTM_LKEY_TYPE_UNAUTH_COMB;
974 } else {
975 SMP_TRACE_ERROR("%s failed to update link_key. Sec Mode = %d, sm4 = 0x%02x",
976 __func__, btm_cb.security_mode, p_dev_rec->sm4);
977 return false;
978 }
979
980 link_key_type += BTM_LTK_DERIVED_LKEY_OFFSET;
981
982 Octet16 notif_link_key;
983 std::reverse_copy(link_key.begin(), link_key.end(), notif_link_key.begin());
984 btm_sec_link_key_notification(bda_for_lk, notif_link_key, link_key_type);
985
986 SMP_TRACE_EVENT("%s is completed", __func__);
987
988 return true;
989 }
990
991 /** The function calculates and saves SC LTK derived from BR/EDR link key. */
smp_calculate_long_term_key_from_link_key(tSMP_CB * p_cb)992 bool smp_calculate_long_term_key_from_link_key(tSMP_CB* p_cb) {
993 tBTM_SEC_DEV_REC* p_dev_rec;
994
995 SMP_TRACE_DEBUG("%s", __func__);
996
997 p_dev_rec = btm_find_dev(p_cb->pairing_bda);
998 if (p_dev_rec == NULL) {
999 SMP_TRACE_ERROR("%s failed to find Security Record", __func__);
1000 return false;
1001 }
1002
1003 uint8_t br_link_key_type;
1004 br_link_key_type = BTM_SecGetDeviceLinkKeyType(p_cb->pairing_bda);
1005 if (br_link_key_type == BTM_LKEY_TYPE_IGNORE) {
1006 SMP_TRACE_ERROR("%s failed to retrieve BR link type", __func__);
1007 return false;
1008 }
1009
1010 if ((br_link_key_type != BTM_LKEY_TYPE_AUTH_COMB_P_256) &&
1011 (br_link_key_type != BTM_LKEY_TYPE_UNAUTH_COMB_P_256)) {
1012 SMP_TRACE_ERROR("%s LE SC LTK can't be derived from LK %d", __func__,
1013 br_link_key_type);
1014 return false;
1015 }
1016
1017 Octet16 rev_link_key;
1018 std::reverse_copy(p_dev_rec->link_key.begin(), p_dev_rec->link_key.end(),
1019 rev_link_key.begin());
1020 p_cb->ltk = crypto_toolbox::link_key_to_ltk(rev_link_key,
1021 p_cb->key_derivation_h7_used);
1022
1023 p_cb->sec_level = (br_link_key_type == BTM_LKEY_TYPE_AUTH_COMB_P_256)
1024 ? SMP_SEC_AUTHENTICATED
1025 : SMP_SEC_UNAUTHENTICATE;
1026 SMP_TRACE_EVENT("%s is completed", __func__);
1027 return true;
1028 }
1029
1030 /**
1031 * This function generates nonce.
1032 */
smp_start_nonce_generation(tSMP_CB * p_cb)1033 void smp_start_nonce_generation(tSMP_CB* p_cb) {
1034 SMP_TRACE_DEBUG("%s", __func__);
1035 btsnd_hcic_ble_rand(Bind(
1036 [](tSMP_CB* p_cb, BT_OCTET8 rand) {
1037 memcpy(p_cb->rand.data(), rand, BT_OCTET8_LEN);
1038 btsnd_hcic_ble_rand(Bind(
1039 [](tSMP_CB* p_cb, BT_OCTET8 rand) {
1040 memcpy(p_cb->rand.data() + 8, rand, BT_OCTET8_LEN);
1041 SMP_TRACE_DEBUG("%s round %d", __func__, p_cb->round);
1042 /* notifies SM that it has new nonce. */
1043 smp_sm_event(p_cb, SMP_HAVE_LOC_NONCE_EVT, NULL);
1044 },
1045 p_cb));
1046 },
1047 p_cb));
1048 }
1049