1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #include <stdio.h> 39 #include <string.h> 40 #include <inttypes.h> 41 42 #include "ble/le_device_db.h" 43 #include "ble/core.h" 44 #include "ble/sm.h" 45 #include "btstack_debug.h" 46 #include "btstack_event.h" 47 #include "btstack_linked_list.h" 48 #include "btstack_memory.h" 49 #include "gap.h" 50 #include "hci.h" 51 #include "l2cap.h" 52 53 // 54 // SM internal types and globals 55 // 56 57 typedef enum { 58 DKG_W4_WORKING, 59 DKG_CALC_IRK, 60 DKG_W4_IRK, 61 DKG_CALC_DHK, 62 DKG_W4_DHK, 63 DKG_READY 64 } derived_key_generation_t; 65 66 typedef enum { 67 RAU_W4_WORKING, 68 RAU_IDLE, 69 RAU_GET_RANDOM, 70 RAU_W4_RANDOM, 71 RAU_GET_ENC, 72 RAU_W4_ENC, 73 RAU_SET_ADDRESS, 74 } random_address_update_t; 75 76 typedef enum { 77 CMAC_IDLE, 78 CMAC_CALC_SUBKEYS, 79 CMAC_W4_SUBKEYS, 80 CMAC_CALC_MI, 81 CMAC_W4_MI, 82 CMAC_CALC_MLAST, 83 CMAC_W4_MLAST 84 } cmac_state_t; 85 86 typedef enum { 87 JUST_WORKS, 88 PK_RESP_INPUT, // Initiator displays PK, initiator inputs PK 89 PK_INIT_INPUT, // Responder displays PK, responder inputs PK 90 OK_BOTH_INPUT, // Only input on both, both input PK 91 OOB // OOB available on both sides 92 } stk_generation_method_t; 93 94 typedef enum { 95 SM_USER_RESPONSE_IDLE, 96 SM_USER_RESPONSE_PENDING, 97 SM_USER_RESPONSE_CONFIRM, 98 SM_USER_RESPONSE_PASSKEY, 99 SM_USER_RESPONSE_DECLINE 100 } sm_user_response_t; 101 102 typedef enum { 103 SM_AES128_IDLE, 104 SM_AES128_ACTIVE 105 } sm_aes128_state_t; 106 107 typedef enum { 108 ADDRESS_RESOLUTION_IDLE, 109 ADDRESS_RESOLUTION_GENERAL, 110 ADDRESS_RESOLUTION_FOR_CONNECTION, 111 } address_resolution_mode_t; 112 113 typedef enum { 114 ADDRESS_RESOLUTION_SUCEEDED, 115 ADDRESS_RESOLUTION_FAILED, 116 } address_resolution_event_t; 117 // 118 // GLOBAL DATA 119 // 120 121 static uint8_t test_use_fixed_local_csrk; 122 123 // configuration 124 static uint8_t sm_accepted_stk_generation_methods; 125 static uint8_t sm_max_encryption_key_size; 126 static uint8_t sm_min_encryption_key_size; 127 static uint8_t sm_auth_req = 0; 128 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 129 static uint8_t sm_slave_request_security; 130 131 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 132 static sm_key_t sm_persistent_er; 133 static sm_key_t sm_persistent_ir; 134 135 // derived from sm_persistent_ir 136 static sm_key_t sm_persistent_dhk; 137 static sm_key_t sm_persistent_irk; 138 static uint8_t sm_persistent_irk_ready = 0; // used for testing 139 static derived_key_generation_t dkg_state; 140 141 // derived from sm_persistent_er 142 // .. 143 144 // random address update 145 static random_address_update_t rau_state; 146 static bd_addr_t sm_random_address; 147 148 // CMAC calculation 149 static cmac_state_t sm_cmac_state; 150 static sm_key_t sm_cmac_k; 151 static uint8_t sm_cmac_header[3]; 152 static uint16_t sm_cmac_message_len; 153 static uint8_t * sm_cmac_message; 154 static uint8_t sm_cmac_sign_counter[4]; 155 static sm_key_t sm_cmac_m_last; 156 static sm_key_t sm_cmac_x; 157 static uint8_t sm_cmac_block_current; 158 static uint8_t sm_cmac_block_count; 159 static void (*sm_cmac_done_handler)(uint8_t hash[8]); 160 161 // resolvable private address lookup / CSRK calculation 162 static int sm_address_resolution_test; 163 static int sm_address_resolution_ah_calculation_active; 164 static uint8_t sm_address_resolution_addr_type; 165 static bd_addr_t sm_address_resolution_address; 166 static void * sm_address_resolution_context; 167 static address_resolution_mode_t sm_address_resolution_mode; 168 static btstack_linked_list_t sm_address_resolution_general_queue; 169 170 // aes128 crypto engine. store current sm_connection_t in sm_aes128_context 171 static sm_aes128_state_t sm_aes128_state; 172 static void * sm_aes128_context; 173 174 // random engine. store context (ususally sm_connection_t) 175 static void * sm_random_context; 176 177 // to receive hci events 178 static btstack_packet_callback_registration_t hci_event_callback_registration; 179 180 /* to dispatch sm event */ 181 static btstack_linked_list_t sm_event_handlers; 182 183 // 184 // Volume 3, Part H, Chapter 24 185 // "Security shall be initiated by the Security Manager in the device in the master role. 186 // The device in the slave role shall be the responding device." 187 // -> master := initiator, slave := responder 188 // 189 190 // data needed for security setup 191 typedef struct sm_setup_context { 192 193 btstack_timer_source_t sm_timeout; 194 195 // used in all phases 196 uint8_t sm_pairing_failed_reason; 197 198 // user response, (Phase 1 and/or 2) 199 uint8_t sm_user_response; 200 201 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 202 int sm_key_distribution_send_set; 203 int sm_key_distribution_received_set; 204 205 // Phase 2 (Pairing over SMP) 206 stk_generation_method_t sm_stk_generation_method; 207 sm_key_t sm_tk; 208 209 sm_key_t sm_c1_t3_value; // c1 calculation 210 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 211 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 212 sm_key_t sm_local_random; 213 sm_key_t sm_local_confirm; 214 sm_key_t sm_peer_random; 215 sm_key_t sm_peer_confirm; 216 uint8_t sm_m_addr_type; // address and type can be removed 217 uint8_t sm_s_addr_type; // '' 218 bd_addr_t sm_m_address; // '' 219 bd_addr_t sm_s_address; // '' 220 sm_key_t sm_ltk; 221 222 // Phase 3 223 224 // key distribution, we generate 225 uint16_t sm_local_y; 226 uint16_t sm_local_div; 227 uint16_t sm_local_ediv; 228 uint8_t sm_local_rand[8]; 229 sm_key_t sm_local_ltk; 230 sm_key_t sm_local_csrk; 231 sm_key_t sm_local_irk; 232 // sm_local_address/addr_type not needed 233 234 // key distribution, received from peer 235 uint16_t sm_peer_y; 236 uint16_t sm_peer_div; 237 uint16_t sm_peer_ediv; 238 uint8_t sm_peer_rand[8]; 239 sm_key_t sm_peer_ltk; 240 sm_key_t sm_peer_irk; 241 sm_key_t sm_peer_csrk; 242 uint8_t sm_peer_addr_type; 243 bd_addr_t sm_peer_address; 244 245 } sm_setup_context_t; 246 247 // 248 static sm_setup_context_t the_setup; 249 static sm_setup_context_t * setup = &the_setup; 250 251 // active connection - the one for which the_setup is used for 252 static uint16_t sm_active_connection = 0; 253 254 // @returns 1 if oob data is available 255 // stores oob data in provided 16 byte buffer if not null 256 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 257 258 // used to notify applicationss that user interaction is neccessary, see sm_notify_t below 259 static btstack_packet_handler_t sm_client_packet_handler = NULL; 260 261 // horizontal: initiator capabilities 262 // vertial: responder capabilities 263 static const stk_generation_method_t stk_generation_method[5][5] = { 264 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 265 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 266 { PK_RESP_INPUT, PK_RESP_INPUT, OK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 267 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 268 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 269 }; 270 271 static void sm_run(void); 272 static void sm_done_for_handle(hci_con_handle_t con_handle); 273 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 274 static inline int sm_calc_actual_encryption_key_size(int other); 275 static int sm_validate_stk_generation_method(void); 276 277 static void log_info_hex16(const char * name, uint16_t value){ 278 log_info("%-6s 0x%04x", name, value); 279 } 280 281 // @returns 1 if all bytes are 0 282 static int sm_is_null_random(uint8_t random[8]){ 283 int i; 284 for (i=0; i < 8 ; i++){ 285 if (random[i]) return 0; 286 } 287 return 1; 288 } 289 290 // Key utils 291 static void sm_reset_tk(void){ 292 int i; 293 for (i=0;i<16;i++){ 294 setup->sm_tk[i] = 0; 295 } 296 } 297 298 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 299 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 300 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 301 int i; 302 for (i = max_encryption_size ; i < 16 ; i++){ 303 key[15-i] = 0; 304 } 305 } 306 307 // SMP Timeout implementation 308 309 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 310 // the Security Manager Timer shall be reset and started. 311 // 312 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 313 // 314 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 315 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 316 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 317 // established. 318 319 static void sm_timeout_handler(btstack_timer_source_t * timer){ 320 log_info("SM timeout"); 321 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 322 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 323 sm_done_for_handle(sm_conn->sm_handle); 324 325 // trigger handling of next ready connection 326 sm_run(); 327 } 328 static void sm_timeout_start(sm_connection_t * sm_conn){ 329 btstack_run_loop_remove_timer(&setup->sm_timeout); 330 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 331 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 332 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 333 btstack_run_loop_add_timer(&setup->sm_timeout); 334 } 335 static void sm_timeout_stop(void){ 336 btstack_run_loop_remove_timer(&setup->sm_timeout); 337 } 338 static void sm_timeout_reset(sm_connection_t * sm_conn){ 339 sm_timeout_stop(); 340 sm_timeout_start(sm_conn); 341 } 342 343 // end of sm timeout 344 345 // GAP Random Address updates 346 static gap_random_address_type_t gap_random_adress_type; 347 static btstack_timer_source_t gap_random_address_update_timer; 348 static uint32_t gap_random_adress_update_period; 349 350 static void gap_random_address_trigger(void){ 351 if (rau_state != RAU_IDLE) return; 352 log_info("gap_random_address_trigger"); 353 rau_state = RAU_GET_RANDOM; 354 sm_run(); 355 } 356 357 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 358 log_info("GAP Random Address Update due"); 359 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 360 btstack_run_loop_add_timer(&gap_random_address_update_timer); 361 gap_random_address_trigger(); 362 } 363 364 static void gap_random_address_update_start(void){ 365 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 366 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 367 btstack_run_loop_add_timer(&gap_random_address_update_timer); 368 } 369 370 static void gap_random_address_update_stop(void){ 371 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 372 } 373 374 375 static void sm_random_start(void * context){ 376 sm_random_context = context; 377 hci_send_cmd(&hci_le_rand); 378 } 379 380 // pre: sm_aes128_state != SM_AES128_ACTIVE, hci_can_send_command == 1 381 // context is made availabe to aes128 result handler by this 382 static void sm_aes128_start(sm_key_t key, sm_key_t plaintext, void * context){ 383 sm_aes128_state = SM_AES128_ACTIVE; 384 sm_key_t key_flipped, plaintext_flipped; 385 reverse_128(key, key_flipped); 386 reverse_128(plaintext, plaintext_flipped); 387 sm_aes128_context = context; 388 hci_send_cmd(&hci_le_encrypt, key_flipped, plaintext_flipped); 389 } 390 391 // ah(k,r) helper 392 // r = padding || r 393 // r - 24 bit value 394 static void sm_ah_r_prime(uint8_t r[3], sm_key_t r_prime){ 395 // r'= padding || r 396 memset(r_prime, 0, 16); 397 memcpy(&r_prime[13], r, 3); 398 } 399 400 // d1 helper 401 // d' = padding || r || d 402 // d,r - 16 bit values 403 static void sm_d1_d_prime(uint16_t d, uint16_t r, sm_key_t d1_prime){ 404 // d'= padding || r || d 405 memset(d1_prime, 0, 16); 406 big_endian_store_16(d1_prime, 12, r); 407 big_endian_store_16(d1_prime, 14, d); 408 } 409 410 // dm helper 411 // r’ = padding || r 412 // r - 64 bit value 413 static void sm_dm_r_prime(uint8_t r[8], sm_key_t r_prime){ 414 memset(r_prime, 0, 16); 415 memcpy(&r_prime[8], r, 8); 416 } 417 418 // calculate arguments for first AES128 operation in C1 function 419 static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, sm_key_t t1){ 420 421 // p1 = pres || preq || rat’ || iat’ 422 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 423 // cant octet of pres becomes the most significant octet of p1. 424 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 425 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 426 // p1 is 0x05000800000302070710000001010001." 427 428 sm_key_t p1; 429 reverse_56(pres, &p1[0]); 430 reverse_56(preq, &p1[7]); 431 p1[14] = rat; 432 p1[15] = iat; 433 log_info_key("p1", p1); 434 log_info_key("r", r); 435 436 // t1 = r xor p1 437 int i; 438 for (i=0;i<16;i++){ 439 t1[i] = r[i] ^ p1[i]; 440 } 441 log_info_key("t1", t1); 442 } 443 444 // calculate arguments for second AES128 operation in C1 function 445 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, sm_key_t t3){ 446 // p2 = padding || ia || ra 447 // "The least significant octet of ra becomes the least significant octet of p2 and 448 // the most significant octet of padding becomes the most significant octet of p2. 449 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 450 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 451 452 sm_key_t p2; 453 memset(p2, 0, 16); 454 memcpy(&p2[4], ia, 6); 455 memcpy(&p2[10], ra, 6); 456 log_info_key("p2", p2); 457 458 // c1 = e(k, t2_xor_p2) 459 int i; 460 for (i=0;i<16;i++){ 461 t3[i] = t2[i] ^ p2[i]; 462 } 463 log_info_key("t3", t3); 464 } 465 466 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, sm_key_t r_prime){ 467 log_info_key("r1", r1); 468 log_info_key("r2", r2); 469 memcpy(&r_prime[8], &r2[8], 8); 470 memcpy(&r_prime[0], &r1[8], 8); 471 } 472 473 static void sm_setup_event_base(uint8_t * event, int event_size, uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 474 event[0] = type; 475 event[1] = event_size - 2; 476 little_endian_store_16(event, 2, con_handle); 477 event[4] = addr_type; 478 reverse_bd_addr(address, &event[5]); 479 } 480 481 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 482 if (sm_client_packet_handler) { 483 sm_client_packet_handler(HCI_EVENT_PACKET, 0, packet, size); 484 } 485 // dispatch to all event handlers 486 btstack_linked_list_iterator_t it; 487 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 488 while (btstack_linked_list_iterator_has_next(&it)){ 489 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 490 entry->callback(packet_type, 0, packet, size); 491 } 492 } 493 494 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 495 uint8_t event[11]; 496 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 497 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 498 } 499 500 static void sm_notify_client_passkey(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint32_t passkey){ 501 uint8_t event[15]; 502 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 503 little_endian_store_32(event, 11, passkey); 504 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 505 } 506 507 static void sm_notify_client_index(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint16_t index){ 508 uint8_t event[13]; 509 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 510 little_endian_store_16(event, 11, index); 511 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 512 } 513 514 static void sm_notify_client_authorization(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint8_t result){ 515 516 uint8_t event[18]; 517 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 518 event[11] = result; 519 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 520 } 521 522 // decide on stk generation based on 523 // - pairing request 524 // - io capabilities 525 // - OOB data availability 526 static void sm_setup_tk(void){ 527 528 // default: just works 529 setup->sm_stk_generation_method = JUST_WORKS; 530 531 // If both devices have out of band authentication data, then the Authentication 532 // Requirements Flags shall be ignored when selecting the pairing method and the 533 // Out of Band pairing method shall be used. 534 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) 535 && sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres)){ 536 log_info("SM: have OOB data"); 537 log_info_key("OOB", setup->sm_tk); 538 setup->sm_stk_generation_method = OOB; 539 return; 540 } 541 542 // Reset TK as it has been setup in sm_init_setup 543 sm_reset_tk(); 544 545 // If both devices have not set the MITM option in the Authentication Requirements 546 // Flags, then the IO capabilities shall be ignored and the Just Works association 547 // model shall be used. 548 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0) 549 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0)){ 550 return; 551 } 552 553 // Also use just works if unknown io capabilites 554 if ((sm_pairing_packet_get_io_capability(setup->sm_m_preq) > IO_CAPABILITY_KEYBOARD_DISPLAY) || (sm_pairing_packet_get_io_capability(setup->sm_s_pres) > IO_CAPABILITY_KEYBOARD_DISPLAY)){ 555 return; 556 } 557 558 // Otherwise the IO capabilities of the devices shall be used to determine the 559 // pairing method as defined in Table 2.4. 560 setup->sm_stk_generation_method = stk_generation_method[sm_pairing_packet_get_io_capability(setup->sm_s_pres)][sm_pairing_packet_get_io_capability(setup->sm_m_preq)]; 561 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 562 sm_pairing_packet_get_io_capability(setup->sm_m_preq), sm_pairing_packet_get_io_capability(setup->sm_s_pres), setup->sm_stk_generation_method); 563 } 564 565 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 566 int flags = 0; 567 if (key_set & SM_KEYDIST_ENC_KEY){ 568 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 569 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 570 } 571 if (key_set & SM_KEYDIST_ID_KEY){ 572 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 573 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 574 } 575 if (key_set & SM_KEYDIST_SIGN){ 576 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 577 } 578 return flags; 579 } 580 581 static void sm_setup_key_distribution(uint8_t key_set){ 582 setup->sm_key_distribution_received_set = 0; 583 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 584 } 585 586 // CSRK Key Lookup 587 588 589 static int sm_address_resolution_idle(void){ 590 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 591 } 592 593 static void sm_address_resolution_start_lookup(uint8_t addr_type, hci_con_handle_t con_handle, bd_addr_t addr, address_resolution_mode_t mode, void * context){ 594 memcpy(sm_address_resolution_address, addr, 6); 595 sm_address_resolution_addr_type = addr_type; 596 sm_address_resolution_test = 0; 597 sm_address_resolution_mode = mode; 598 sm_address_resolution_context = context; 599 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 600 } 601 602 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 603 // check if already in list 604 btstack_linked_list_iterator_t it; 605 sm_lookup_entry_t * entry; 606 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 607 while(btstack_linked_list_iterator_has_next(&it)){ 608 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 609 if (entry->address_type != address_type) continue; 610 if (memcmp(entry->address, address, 6)) continue; 611 // already in list 612 return BTSTACK_BUSY; 613 } 614 entry = btstack_memory_sm_lookup_entry_get(); 615 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 616 entry->address_type = (bd_addr_type_t) address_type; 617 memcpy(entry->address, address, 6); 618 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 619 sm_run(); 620 return 0; 621 } 622 623 // CMAC Implementation using AES128 engine 624 static void sm_shift_left_by_one_bit_inplace(int len, uint8_t * data){ 625 int i; 626 int carry = 0; 627 for (i=len-1; i >= 0 ; i--){ 628 int new_carry = data[i] >> 7; 629 data[i] = data[i] << 1 | carry; 630 carry = new_carry; 631 } 632 } 633 634 // while x_state++ for an enum is possible in C, it isn't in C++. we use this helpers to avoid compile errors for now 635 static inline void sm_next_responding_state(sm_connection_t * sm_conn){ 636 sm_conn->sm_engine_state = (security_manager_state_t) (((int)sm_conn->sm_engine_state) + 1); 637 } 638 static inline void dkg_next_state(void){ 639 dkg_state = (derived_key_generation_t) (((int)dkg_state) + 1); 640 } 641 static inline void rau_next_state(void){ 642 rau_state = (random_address_update_t) (((int)rau_state) + 1); 643 } 644 static inline void sm_cmac_next_state(void){ 645 sm_cmac_state = (cmac_state_t) (((int)sm_cmac_state) + 1); 646 } 647 static int sm_cmac_last_block_complete(void){ 648 if (sm_cmac_message_len == 0) return 0; 649 return (sm_cmac_message_len & 0x0f) == 0; 650 } 651 static inline uint8_t sm_cmac_message_get_byte(int offset){ 652 if (offset >= sm_cmac_message_len) { 653 log_error("sm_cmac_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_message_len); 654 return 0; 655 } 656 657 offset = sm_cmac_message_len - 1 - offset; 658 659 // sm_cmac_header[3] | message[] | sm_cmac_sign_counter[4] 660 if (offset < 3){ 661 return sm_cmac_header[offset]; 662 } 663 int actual_message_len_incl_header = sm_cmac_message_len - 4; 664 if (offset < actual_message_len_incl_header){ 665 return sm_cmac_message[offset - 3]; 666 } 667 return sm_cmac_sign_counter[offset - actual_message_len_incl_header]; 668 } 669 670 void sm_cmac_start(sm_key_t k, uint8_t opcode, hci_con_handle_t con_handle, uint16_t message_len, uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t hash[8])){ 671 memcpy(sm_cmac_k, k, 16); 672 sm_cmac_header[0] = opcode; 673 little_endian_store_16(sm_cmac_header, 1, con_handle); 674 little_endian_store_32(sm_cmac_sign_counter, 0, sign_counter); 675 sm_cmac_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 676 sm_cmac_message = message; 677 sm_cmac_done_handler = done_handler; 678 sm_cmac_block_current = 0; 679 memset(sm_cmac_x, 0, 16); 680 681 // step 2: n := ceil(len/const_Bsize); 682 sm_cmac_block_count = (sm_cmac_message_len + 15) / 16; 683 684 // step 3: .. 685 if (sm_cmac_block_count==0){ 686 sm_cmac_block_count = 1; 687 } 688 689 log_info("sm_cmac_start: len %u, block count %u", sm_cmac_message_len, sm_cmac_block_count); 690 691 // first, we need to compute l for k1, k2, and m_last 692 sm_cmac_state = CMAC_CALC_SUBKEYS; 693 694 // let's go 695 sm_run(); 696 } 697 698 int sm_cmac_ready(void){ 699 return sm_cmac_state == CMAC_IDLE; 700 } 701 702 static void sm_cmac_handle_aes_engine_ready(void){ 703 switch (sm_cmac_state){ 704 case CMAC_CALC_SUBKEYS: { 705 sm_key_t const_zero; 706 memset(const_zero, 0, 16); 707 sm_cmac_next_state(); 708 sm_aes128_start(sm_cmac_k, const_zero, NULL); 709 break; 710 } 711 case CMAC_CALC_MI: { 712 int j; 713 sm_key_t y; 714 for (j=0;j<16;j++){ 715 y[j] = sm_cmac_x[j] ^ sm_cmac_message_get_byte(sm_cmac_block_current*16 + j); 716 } 717 sm_cmac_block_current++; 718 sm_cmac_next_state(); 719 sm_aes128_start(sm_cmac_k, y, NULL); 720 break; 721 } 722 case CMAC_CALC_MLAST: { 723 int i; 724 sm_key_t y; 725 for (i=0;i<16;i++){ 726 y[i] = sm_cmac_x[i] ^ sm_cmac_m_last[i]; 727 } 728 log_info_key("Y", y); 729 sm_cmac_block_current++; 730 sm_cmac_next_state(); 731 sm_aes128_start(sm_cmac_k, y, NULL); 732 break; 733 } 734 default: 735 log_info("sm_cmac_handle_aes_engine_ready called in state %u", sm_cmac_state); 736 break; 737 } 738 } 739 740 static void sm_cmac_handle_encryption_result(sm_key_t data){ 741 switch (sm_cmac_state){ 742 case CMAC_W4_SUBKEYS: { 743 sm_key_t k1; 744 memcpy(k1, data, 16); 745 sm_shift_left_by_one_bit_inplace(16, k1); 746 if (data[0] & 0x80){ 747 k1[15] ^= 0x87; 748 } 749 sm_key_t k2; 750 memcpy(k2, k1, 16); 751 sm_shift_left_by_one_bit_inplace(16, k2); 752 if (k1[0] & 0x80){ 753 k2[15] ^= 0x87; 754 } 755 756 log_info_key("k", sm_cmac_k); 757 log_info_key("k1", k1); 758 log_info_key("k2", k2); 759 760 // step 4: set m_last 761 int i; 762 if (sm_cmac_last_block_complete()){ 763 for (i=0;i<16;i++){ 764 sm_cmac_m_last[i] = sm_cmac_message_get_byte(sm_cmac_message_len - 16 + i) ^ k1[i]; 765 } 766 } else { 767 int valid_octets_in_last_block = sm_cmac_message_len & 0x0f; 768 for (i=0;i<16;i++){ 769 if (i < valid_octets_in_last_block){ 770 sm_cmac_m_last[i] = sm_cmac_message_get_byte((sm_cmac_message_len & 0xfff0) + i) ^ k2[i]; 771 continue; 772 } 773 if (i == valid_octets_in_last_block){ 774 sm_cmac_m_last[i] = 0x80 ^ k2[i]; 775 continue; 776 } 777 sm_cmac_m_last[i] = k2[i]; 778 } 779 } 780 781 // next 782 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 783 break; 784 } 785 case CMAC_W4_MI: 786 memcpy(sm_cmac_x, data, 16); 787 sm_cmac_state = sm_cmac_block_current < sm_cmac_block_count - 1 ? CMAC_CALC_MI : CMAC_CALC_MLAST; 788 break; 789 case CMAC_W4_MLAST: 790 // done 791 log_info_key("CMAC", data); 792 sm_cmac_done_handler(data); 793 sm_cmac_state = CMAC_IDLE; 794 break; 795 default: 796 log_info("sm_cmac_handle_encryption_result called in state %u", sm_cmac_state); 797 break; 798 } 799 } 800 801 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 802 // notify client for: JUST WORKS confirm, PASSKEY display or input 803 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 804 switch (setup->sm_stk_generation_method){ 805 case PK_RESP_INPUT: 806 if (sm_conn->sm_role){ 807 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 808 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 809 } else { 810 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 811 } 812 break; 813 case PK_INIT_INPUT: 814 if (sm_conn->sm_role){ 815 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 816 } else { 817 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 818 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 819 } 820 break; 821 case OK_BOTH_INPUT: 822 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 823 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 824 break; 825 case JUST_WORKS: 826 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 827 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 828 break; 829 case OOB: 830 // client already provided OOB data, let's skip notification. 831 break; 832 } 833 } 834 835 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 836 int recv_flags; 837 if (sm_conn->sm_role){ 838 // slave / responser 839 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 840 } else { 841 // master / initiator 842 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 843 } 844 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 845 return recv_flags == setup->sm_key_distribution_received_set; 846 } 847 848 static void sm_done_for_handle(hci_con_handle_t con_handle){ 849 if (sm_active_connection == con_handle){ 850 sm_timeout_stop(); 851 sm_active_connection = 0; 852 log_info("sm: connection 0x%x released setup context", con_handle); 853 } 854 } 855 856 static int sm_key_distribution_flags_for_auth_req(void){ 857 int flags = SM_KEYDIST_ID_KEY | SM_KEYDIST_SIGN; 858 if (sm_auth_req & SM_AUTHREQ_BONDING){ 859 // encryption information only if bonding requested 860 flags |= SM_KEYDIST_ENC_KEY; 861 } 862 return flags; 863 } 864 865 static void sm_init_setup(sm_connection_t * sm_conn){ 866 867 // fill in sm setup 868 sm_reset_tk(); 869 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 870 memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 871 872 // query client for OOB data 873 int have_oob_data = 0; 874 if (sm_get_oob_data) { 875 have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 876 } 877 878 sm_pairing_packet_t * local_packet; 879 if (sm_conn->sm_role){ 880 // slave 881 local_packet = &setup->sm_s_pres; 882 gap_advertisements_get_address(&setup->sm_s_addr_type, setup->sm_s_address); 883 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 884 memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 885 } else { 886 // master 887 local_packet = &setup->sm_m_preq; 888 gap_advertisements_get_address(&setup->sm_m_addr_type, setup->sm_m_address); 889 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 890 memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 891 892 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 893 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 894 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 895 } 896 897 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 898 sm_pairing_packet_set_oob_data_flag(*local_packet, have_oob_data); 899 sm_pairing_packet_set_auth_req(*local_packet, sm_auth_req); 900 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 901 } 902 903 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 904 905 sm_pairing_packet_t * remote_packet; 906 int remote_key_request; 907 if (sm_conn->sm_role){ 908 // slave / responser 909 remote_packet = &setup->sm_m_preq; 910 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 911 } else { 912 // master / initiator 913 remote_packet = &setup->sm_s_pres; 914 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 915 } 916 917 // check key size 918 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 919 if (sm_conn->sm_actual_encryption_key_size == 0) return SM_REASON_ENCRYPTION_KEY_SIZE; 920 921 // setup key distribution 922 sm_setup_key_distribution(remote_key_request); 923 924 // identical to responder 925 926 // decide on STK generation method 927 sm_setup_tk(); 928 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 929 930 // check if STK generation method is acceptable by client 931 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 932 933 // JUST WORKS doens't provide authentication 934 sm_conn->sm_connection_authenticated = setup->sm_stk_generation_method == JUST_WORKS ? 0 : 1; 935 936 return 0; 937 } 938 939 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 940 941 // cache and reset context 942 int matched_device_id = sm_address_resolution_test; 943 address_resolution_mode_t mode = sm_address_resolution_mode; 944 void * context = sm_address_resolution_context; 945 946 // reset context 947 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 948 sm_address_resolution_context = NULL; 949 sm_address_resolution_test = -1; 950 hci_con_handle_t con_handle = 0; 951 952 sm_connection_t * sm_connection; 953 uint16_t ediv; 954 switch (mode){ 955 case ADDRESS_RESOLUTION_GENERAL: 956 break; 957 case ADDRESS_RESOLUTION_FOR_CONNECTION: 958 sm_connection = (sm_connection_t *) context; 959 con_handle = sm_connection->sm_handle; 960 switch (event){ 961 case ADDRESS_RESOLUTION_SUCEEDED: 962 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 963 sm_connection->sm_le_db_index = matched_device_id; 964 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 965 if (sm_connection->sm_role) break; 966 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 967 sm_connection->sm_security_request_received = 0; 968 sm_connection->sm_bonding_requested = 0; 969 le_device_db_encryption_get(sm_connection->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 970 if (ediv){ 971 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 972 } else { 973 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 974 } 975 break; 976 case ADDRESS_RESOLUTION_FAILED: 977 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 978 if (sm_connection->sm_role) break; 979 if (!sm_connection->sm_bonding_requested && !sm_connection->sm_security_request_received) break; 980 sm_connection->sm_security_request_received = 0; 981 sm_connection->sm_bonding_requested = 0; 982 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 983 break; 984 } 985 break; 986 default: 987 break; 988 } 989 990 switch (event){ 991 case ADDRESS_RESOLUTION_SUCEEDED: 992 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 993 break; 994 case ADDRESS_RESOLUTION_FAILED: 995 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 996 break; 997 } 998 } 999 1000 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1001 1002 int le_db_index = -1; 1003 1004 // lookup device based on IRK 1005 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1006 int i; 1007 for (i=0; i < le_device_db_count(); i++){ 1008 sm_key_t irk; 1009 bd_addr_t address; 1010 int address_type; 1011 le_device_db_info(i, &address_type, address, irk); 1012 if (memcmp(irk, setup->sm_peer_irk, 16) == 0){ 1013 log_info("sm: device found for IRK, updating"); 1014 le_db_index = i; 1015 break; 1016 } 1017 } 1018 } 1019 1020 // if not found, lookup via public address if possible 1021 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1022 if (le_db_index < 0 && setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1023 int i; 1024 for (i=0; i < le_device_db_count(); i++){ 1025 bd_addr_t address; 1026 int address_type; 1027 le_device_db_info(i, &address_type, address, NULL); 1028 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1029 if (address_type == BD_ADDR_TYPE_LE_PUBLIC && memcmp(address, setup->sm_peer_address, 6) == 0){ 1030 log_info("sm: device found for public address, updating"); 1031 le_db_index = i; 1032 break; 1033 } 1034 } 1035 } 1036 1037 // if not found, add to db 1038 if (le_db_index < 0) { 1039 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1040 } 1041 1042 if (le_db_index >= 0){ 1043 le_device_db_local_counter_set(le_db_index, 0); 1044 1045 // store local CSRK 1046 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1047 log_info("sm: store local CSRK"); 1048 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1049 le_device_db_local_counter_set(le_db_index, 0); 1050 } 1051 1052 // store remote CSRK 1053 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1054 log_info("sm: store remote CSRK"); 1055 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1056 le_device_db_remote_counter_set(le_db_index, 0); 1057 } 1058 1059 // store encryption information 1060 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION 1061 && setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 1062 log_info("sm: set encryption information (key size %u, authenticatd %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1063 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1064 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED); 1065 } 1066 } 1067 1068 // keep le_db_index 1069 sm_conn->sm_le_db_index = le_db_index; 1070 } 1071 1072 static void sm_run(void){ 1073 1074 btstack_linked_list_iterator_t it; 1075 1076 // assert that we can send at least commands 1077 if (!hci_can_send_command_packet_now()) return; 1078 1079 // 1080 // non-connection related behaviour 1081 // 1082 1083 // distributed key generation 1084 switch (dkg_state){ 1085 case DKG_CALC_IRK: 1086 // already busy? 1087 if (sm_aes128_state == SM_AES128_IDLE) { 1088 // IRK = d1(IR, 1, 0) 1089 sm_key_t d1_prime; 1090 sm_d1_d_prime(1, 0, d1_prime); // plaintext 1091 dkg_next_state(); 1092 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1093 return; 1094 } 1095 break; 1096 case DKG_CALC_DHK: 1097 // already busy? 1098 if (sm_aes128_state == SM_AES128_IDLE) { 1099 // DHK = d1(IR, 3, 0) 1100 sm_key_t d1_prime; 1101 sm_d1_d_prime(3, 0, d1_prime); // plaintext 1102 dkg_next_state(); 1103 sm_aes128_start(sm_persistent_ir, d1_prime, NULL); 1104 return; 1105 } 1106 break; 1107 default: 1108 break; 1109 } 1110 1111 // random address updates 1112 switch (rau_state){ 1113 case RAU_GET_RANDOM: 1114 rau_next_state(); 1115 sm_random_start(NULL); 1116 return; 1117 case RAU_GET_ENC: 1118 // already busy? 1119 if (sm_aes128_state == SM_AES128_IDLE) { 1120 sm_key_t r_prime; 1121 sm_ah_r_prime(sm_random_address, r_prime); 1122 rau_next_state(); 1123 sm_aes128_start(sm_persistent_irk, r_prime, NULL); 1124 return; 1125 } 1126 break; 1127 case RAU_SET_ADDRESS: 1128 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1129 rau_state = RAU_IDLE; 1130 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1131 return; 1132 default: 1133 break; 1134 } 1135 1136 // CMAC 1137 switch (sm_cmac_state){ 1138 case CMAC_CALC_SUBKEYS: 1139 case CMAC_CALC_MI: 1140 case CMAC_CALC_MLAST: 1141 // already busy? 1142 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1143 sm_cmac_handle_aes_engine_ready(); 1144 return; 1145 default: 1146 break; 1147 } 1148 1149 // CSRK Lookup 1150 // -- if csrk lookup ready, find connection that require csrk lookup 1151 if (sm_address_resolution_idle()){ 1152 hci_connections_get_iterator(&it); 1153 while(btstack_linked_list_iterator_has_next(&it)){ 1154 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1155 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1156 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1157 // and start lookup 1158 sm_address_resolution_start_lookup(sm_connection->sm_peer_addr_type, sm_connection->sm_handle, sm_connection->sm_peer_address, ADDRESS_RESOLUTION_FOR_CONNECTION, sm_connection); 1159 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1160 break; 1161 } 1162 } 1163 } 1164 1165 // -- if csrk lookup ready, resolved addresses for received addresses 1166 if (sm_address_resolution_idle()) { 1167 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1168 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1169 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1170 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1171 btstack_memory_sm_lookup_entry_free(entry); 1172 } 1173 } 1174 1175 // -- Continue with CSRK device lookup by public or resolvable private address 1176 if (!sm_address_resolution_idle()){ 1177 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_count()); 1178 while (sm_address_resolution_test < le_device_db_count()){ 1179 int addr_type; 1180 bd_addr_t addr; 1181 sm_key_t irk; 1182 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1183 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1184 1185 if (sm_address_resolution_addr_type == addr_type && memcmp(addr, sm_address_resolution_address, 6) == 0){ 1186 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1187 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1188 break; 1189 } 1190 1191 if (sm_address_resolution_addr_type == 0){ 1192 sm_address_resolution_test++; 1193 continue; 1194 } 1195 1196 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1197 1198 log_info("LE Device Lookup: calculate AH"); 1199 log_info_key("IRK", irk); 1200 1201 sm_key_t r_prime; 1202 sm_ah_r_prime(sm_address_resolution_address, r_prime); 1203 sm_address_resolution_ah_calculation_active = 1; 1204 sm_aes128_start(irk, r_prime, sm_address_resolution_context); // keep context 1205 return; 1206 } 1207 1208 if (sm_address_resolution_test >= le_device_db_count()){ 1209 log_info("LE Device Lookup: not found"); 1210 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 1211 } 1212 } 1213 1214 1215 // 1216 // active connection handling 1217 // -- use loop to handle next connection if lock on setup context is released 1218 1219 while (1) { 1220 1221 // Find connections that requires setup context and make active if no other is locked 1222 hci_connections_get_iterator(&it); 1223 while(!sm_active_connection && btstack_linked_list_iterator_has_next(&it)){ 1224 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1225 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1226 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 1227 int done = 1; 1228 int err; 1229 int encryption_key_size; 1230 int authenticated; 1231 int authorized; 1232 switch (sm_connection->sm_engine_state) { 1233 case SM_RESPONDER_SEND_SECURITY_REQUEST: 1234 // send packet if possible, 1235 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 1236 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, SM_AUTHREQ_BONDING}; 1237 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 1238 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1239 } else { 1240 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1241 } 1242 // don't lock setup context yet 1243 done = 0; 1244 break; 1245 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 1246 sm_init_setup(sm_connection); 1247 // recover pairing request 1248 memcpy(&setup->sm_m_preq, &sm_connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 1249 err = sm_stk_generation_init(sm_connection); 1250 if (err){ 1251 setup->sm_pairing_failed_reason = err; 1252 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1253 break; 1254 } 1255 sm_timeout_start(sm_connection); 1256 // generate random number first, if we need to show passkey 1257 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 1258 sm_connection->sm_engine_state = SM_PH2_GET_RANDOM_TK; 1259 break; 1260 } 1261 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1262 break; 1263 case SM_INITIATOR_PH0_HAS_LTK: 1264 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1265 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1266 &encryption_key_size, &authenticated, &authorized); 1267 log_info("db index %u, key size %u, authenticated %u, authorized %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized); 1268 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1269 sm_connection->sm_connection_authenticated = authenticated; 1270 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1271 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 1272 break; 1273 case SM_RESPONDER_PH0_RECEIVED_LTK: 1274 // re-establish previously used LTK using Rand and EDIV 1275 memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1276 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1277 // re-establish used key encryption size 1278 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1279 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7] & 0x0f) + 1; 1280 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1281 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7] & 0x10) >> 4; 1282 log_info("sm: received ltk request with key size %u, authenticated %u", 1283 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1284 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1285 break; 1286 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 1287 sm_init_setup(sm_connection); 1288 sm_timeout_start(sm_connection); 1289 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 1290 break; 1291 default: 1292 done = 0; 1293 break; 1294 } 1295 if (done){ 1296 sm_active_connection = sm_connection->sm_handle; 1297 log_info("sm: connection 0x%04x locked setup context as %s", sm_active_connection, sm_connection->sm_role ? "responder" : "initiator"); 1298 } 1299 } 1300 1301 // 1302 // active connection handling 1303 // 1304 1305 if (sm_active_connection == 0) return; 1306 1307 // assert that we could send a SM PDU - not needed for all of the following 1308 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 1309 l2cap_request_can_send_fix_channel_now_event(sm_active_connection, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 1310 return; 1311 } 1312 1313 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection); 1314 if (!connection) return; 1315 1316 sm_key_t plaintext; 1317 int key_distribution_flags; 1318 1319 log_info("sm_run: state %u", connection->sm_engine_state); 1320 1321 // responding state 1322 switch (connection->sm_engine_state){ 1323 1324 // general 1325 case SM_GENERAL_SEND_PAIRING_FAILED: { 1326 uint8_t buffer[2]; 1327 buffer[0] = SM_CODE_PAIRING_FAILED; 1328 buffer[1] = setup->sm_pairing_failed_reason; 1329 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 1330 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1331 sm_done_for_handle(connection->sm_handle); 1332 break; 1333 } 1334 1335 // initiator side 1336 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 1337 sm_key_t peer_ltk_flipped; 1338 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 1339 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 1340 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 1341 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 1342 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 1343 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 1344 return; 1345 } 1346 1347 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 1348 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 1349 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 1350 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 1351 sm_timeout_reset(connection); 1352 break; 1353 1354 // responder side 1355 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 1356 connection->sm_engine_state = SM_RESPONDER_IDLE; 1357 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 1358 return; 1359 1360 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 1361 // echo initiator for now 1362 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 1363 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1364 sm_pairing_packet_set_initiator_key_distribution(setup->sm_s_pres, sm_pairing_packet_get_initiator_key_distribution(setup->sm_m_preq) & key_distribution_flags); 1365 sm_pairing_packet_set_responder_key_distribution(setup->sm_s_pres, sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq) & key_distribution_flags); 1366 1367 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 1368 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 1369 sm_timeout_reset(connection); 1370 sm_trigger_user_response(connection); 1371 return; 1372 1373 case SM_PH2_SEND_PAIRING_RANDOM: { 1374 uint8_t buffer[17]; 1375 buffer[0] = SM_CODE_PAIRING_RANDOM; 1376 reverse_128(setup->sm_local_random, &buffer[1]); 1377 if (connection->sm_role){ 1378 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 1379 } else { 1380 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 1381 } 1382 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1383 sm_timeout_reset(connection); 1384 break; 1385 } 1386 1387 case SM_PH2_GET_RANDOM_TK: 1388 case SM_PH2_C1_GET_RANDOM_A: 1389 case SM_PH2_C1_GET_RANDOM_B: 1390 case SM_PH3_GET_RANDOM: 1391 case SM_PH3_GET_DIV: 1392 sm_next_responding_state(connection); 1393 sm_random_start(connection); 1394 return; 1395 1396 case SM_PH2_C1_GET_ENC_B: 1397 case SM_PH2_C1_GET_ENC_D: 1398 // already busy? 1399 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1400 sm_next_responding_state(connection); 1401 sm_aes128_start(setup->sm_tk, setup->sm_c1_t3_value, connection); 1402 return; 1403 1404 case SM_PH3_LTK_GET_ENC: 1405 case SM_RESPONDER_PH4_LTK_GET_ENC: 1406 // already busy? 1407 if (sm_aes128_state == SM_AES128_IDLE) { 1408 sm_key_t d_prime; 1409 sm_d1_d_prime(setup->sm_local_div, 0, d_prime); 1410 sm_next_responding_state(connection); 1411 sm_aes128_start(sm_persistent_er, d_prime, connection); 1412 return; 1413 } 1414 break; 1415 1416 case SM_PH3_CSRK_GET_ENC: 1417 // already busy? 1418 if (sm_aes128_state == SM_AES128_IDLE) { 1419 sm_key_t d_prime; 1420 sm_d1_d_prime(setup->sm_local_div, 1, d_prime); 1421 sm_next_responding_state(connection); 1422 sm_aes128_start(sm_persistent_er, d_prime, connection); 1423 return; 1424 } 1425 break; 1426 1427 case SM_PH2_C1_GET_ENC_C: 1428 // already busy? 1429 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1430 // calculate m_confirm using aes128 engine - step 1 1431 sm_c1_t1(setup->sm_peer_random, (uint8_t*) &setup->sm_m_preq, (uint8_t*) &setup->sm_s_pres, setup->sm_m_addr_type, setup->sm_s_addr_type, plaintext); 1432 sm_next_responding_state(connection); 1433 sm_aes128_start(setup->sm_tk, plaintext, connection); 1434 break; 1435 case SM_PH2_C1_GET_ENC_A: 1436 // already busy? 1437 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1438 // calculate confirm using aes128 engine - step 1 1439 sm_c1_t1(setup->sm_local_random, (uint8_t*) &setup->sm_m_preq, (uint8_t*) &setup->sm_s_pres, setup->sm_m_addr_type, setup->sm_s_addr_type, plaintext); 1440 sm_next_responding_state(connection); 1441 sm_aes128_start(setup->sm_tk, plaintext, connection); 1442 break; 1443 case SM_PH2_CALC_STK: 1444 // already busy? 1445 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1446 // calculate STK 1447 if (connection->sm_role){ 1448 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, plaintext); 1449 } else { 1450 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, plaintext); 1451 } 1452 sm_next_responding_state(connection); 1453 sm_aes128_start(setup->sm_tk, plaintext, connection); 1454 break; 1455 case SM_PH3_Y_GET_ENC: 1456 // already busy? 1457 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1458 // PH3B2 - calculate Y from - enc 1459 // Y = dm(DHK, Rand) 1460 sm_dm_r_prime(setup->sm_local_rand, plaintext); 1461 sm_next_responding_state(connection); 1462 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 1463 return; 1464 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 1465 uint8_t buffer[17]; 1466 buffer[0] = SM_CODE_PAIRING_CONFIRM; 1467 reverse_128(setup->sm_local_confirm, &buffer[1]); 1468 if (connection->sm_role){ 1469 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 1470 } else { 1471 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 1472 } 1473 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1474 sm_timeout_reset(connection); 1475 return; 1476 } 1477 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 1478 sm_key_t stk_flipped; 1479 reverse_128(setup->sm_ltk, stk_flipped); 1480 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 1481 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 1482 return; 1483 } 1484 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 1485 sm_key_t stk_flipped; 1486 reverse_128(setup->sm_ltk, stk_flipped); 1487 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 1488 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 1489 return; 1490 } 1491 case SM_RESPONDER_PH4_SEND_LTK: { 1492 sm_key_t ltk_flipped; 1493 reverse_128(setup->sm_ltk, ltk_flipped); 1494 connection->sm_engine_state = SM_RESPONDER_IDLE; 1495 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 1496 return; 1497 } 1498 case SM_RESPONDER_PH4_Y_GET_ENC: 1499 // already busy? 1500 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1501 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 1502 // Y = dm(DHK, Rand) 1503 sm_dm_r_prime(setup->sm_local_rand, plaintext); 1504 sm_next_responding_state(connection); 1505 sm_aes128_start(sm_persistent_dhk, plaintext, connection); 1506 return; 1507 1508 case SM_PH3_DISTRIBUTE_KEYS: 1509 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 1510 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 1511 uint8_t buffer[17]; 1512 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 1513 reverse_128(setup->sm_ltk, &buffer[1]); 1514 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1515 sm_timeout_reset(connection); 1516 return; 1517 } 1518 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 1519 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 1520 uint8_t buffer[11]; 1521 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 1522 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 1523 reverse_64(setup->sm_local_rand, &buffer[3]); 1524 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1525 sm_timeout_reset(connection); 1526 return; 1527 } 1528 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1529 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 1530 uint8_t buffer[17]; 1531 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 1532 reverse_128(sm_persistent_irk, &buffer[1]); 1533 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1534 sm_timeout_reset(connection); 1535 return; 1536 } 1537 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 1538 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 1539 bd_addr_t local_address; 1540 uint8_t buffer[8]; 1541 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 1542 gap_advertisements_get_address(&buffer[1], local_address); 1543 reverse_bd_addr(local_address, &buffer[2]); 1544 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1545 sm_timeout_reset(connection); 1546 return; 1547 } 1548 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1549 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 1550 1551 // hack to reproduce test runs 1552 if (test_use_fixed_local_csrk){ 1553 memset(setup->sm_local_csrk, 0xcc, 16); 1554 } 1555 1556 uint8_t buffer[17]; 1557 buffer[0] = SM_CODE_SIGNING_INFORMATION; 1558 reverse_128(setup->sm_local_csrk, &buffer[1]); 1559 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 1560 sm_timeout_reset(connection); 1561 return; 1562 } 1563 1564 // keys are sent 1565 if (connection->sm_role){ 1566 // slave -> receive master keys if any 1567 if (sm_key_distribution_all_received(connection)){ 1568 sm_key_distribution_handle_all_received(connection); 1569 connection->sm_engine_state = SM_RESPONDER_IDLE; 1570 sm_done_for_handle(connection->sm_handle); 1571 } else { 1572 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 1573 } 1574 } else { 1575 // master -> all done 1576 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1577 sm_done_for_handle(connection->sm_handle); 1578 } 1579 break; 1580 1581 default: 1582 break; 1583 } 1584 1585 // check again if active connection was released 1586 if (sm_active_connection) break; 1587 } 1588 } 1589 1590 // note: aes engine is ready as we just got the aes result 1591 static void sm_handle_encryption_result(uint8_t * data){ 1592 1593 sm_aes128_state = SM_AES128_IDLE; 1594 1595 if (sm_address_resolution_ah_calculation_active){ 1596 sm_address_resolution_ah_calculation_active = 0; 1597 // compare calulated address against connecting device 1598 uint8_t hash[3]; 1599 reverse_24(data, hash); 1600 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 1601 log_info("LE Device Lookup: matched resolvable private address"); 1602 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1603 return; 1604 } 1605 // no match, try next 1606 sm_address_resolution_test++; 1607 return; 1608 } 1609 1610 switch (dkg_state){ 1611 case DKG_W4_IRK: 1612 reverse_128(data, sm_persistent_irk); 1613 log_info_key("irk", sm_persistent_irk); 1614 dkg_next_state(); 1615 return; 1616 case DKG_W4_DHK: 1617 reverse_128(data, sm_persistent_dhk); 1618 log_info_key("dhk", sm_persistent_dhk); 1619 dkg_next_state(); 1620 // SM Init Finished 1621 return; 1622 default: 1623 break; 1624 } 1625 1626 switch (rau_state){ 1627 case RAU_W4_ENC: 1628 reverse_24(data, &sm_random_address[3]); 1629 rau_next_state(); 1630 return; 1631 default: 1632 break; 1633 } 1634 1635 switch (sm_cmac_state){ 1636 case CMAC_W4_SUBKEYS: 1637 case CMAC_W4_MI: 1638 case CMAC_W4_MLAST: 1639 { 1640 sm_key_t t; 1641 reverse_128(data, t); 1642 sm_cmac_handle_encryption_result(t); 1643 } 1644 return; 1645 default: 1646 break; 1647 } 1648 1649 // retrieve sm_connection provided to sm_aes128_start_encryption 1650 sm_connection_t * connection = (sm_connection_t*) sm_aes128_context; 1651 if (!connection) return; 1652 switch (connection->sm_engine_state){ 1653 case SM_PH2_C1_W4_ENC_A: 1654 case SM_PH2_C1_W4_ENC_C: 1655 { 1656 sm_key_t t2; 1657 reverse_128(data, t2); 1658 sm_c1_t3(t2, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 1659 } 1660 sm_next_responding_state(connection); 1661 return; 1662 case SM_PH2_C1_W4_ENC_B: 1663 reverse_128(data, setup->sm_local_confirm); 1664 log_info_key("c1!", setup->sm_local_confirm); 1665 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 1666 return; 1667 case SM_PH2_C1_W4_ENC_D: 1668 { 1669 sm_key_t peer_confirm_test; 1670 reverse_128(data, peer_confirm_test); 1671 log_info_key("c1!", peer_confirm_test); 1672 if (memcmp(setup->sm_peer_confirm, peer_confirm_test, 16) != 0){ 1673 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 1674 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1675 return; 1676 } 1677 if (connection->sm_role){ 1678 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 1679 } else { 1680 connection->sm_engine_state = SM_PH2_CALC_STK; 1681 } 1682 } 1683 return; 1684 case SM_PH2_W4_STK: 1685 reverse_128(data, setup->sm_ltk); 1686 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 1687 log_info_key("stk", setup->sm_ltk); 1688 if (connection->sm_role){ 1689 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 1690 } else { 1691 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1692 } 1693 return; 1694 case SM_PH3_Y_W4_ENC:{ 1695 sm_key_t y128; 1696 reverse_128(data, y128); 1697 setup->sm_local_y = big_endian_read_16(y128, 14); 1698 log_info_hex16("y", setup->sm_local_y); 1699 // PH3B3 - calculate EDIV 1700 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 1701 log_info_hex16("ediv", setup->sm_local_ediv); 1702 // PH3B4 - calculate LTK - enc 1703 // LTK = d1(ER, DIV, 0)) 1704 connection->sm_engine_state = SM_PH3_LTK_GET_ENC; 1705 return; 1706 } 1707 case SM_RESPONDER_PH4_Y_W4_ENC:{ 1708 sm_key_t y128; 1709 reverse_128(data, y128); 1710 setup->sm_local_y = big_endian_read_16(y128, 14); 1711 log_info_hex16("y", setup->sm_local_y); 1712 1713 // PH3B3 - calculate DIV 1714 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 1715 log_info_hex16("ediv", setup->sm_local_ediv); 1716 // PH3B4 - calculate LTK - enc 1717 // LTK = d1(ER, DIV, 0)) 1718 connection->sm_engine_state = SM_RESPONDER_PH4_LTK_GET_ENC; 1719 return; 1720 } 1721 case SM_PH3_LTK_W4_ENC: 1722 reverse_128(data, setup->sm_ltk); 1723 log_info_key("ltk", setup->sm_ltk); 1724 // calc CSRK next 1725 connection->sm_engine_state = SM_PH3_CSRK_GET_ENC; 1726 return; 1727 case SM_PH3_CSRK_W4_ENC: 1728 reverse_128(data, setup->sm_local_csrk); 1729 log_info_key("csrk", setup->sm_local_csrk); 1730 if (setup->sm_key_distribution_send_set){ 1731 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 1732 } else { 1733 // no keys to send, just continue 1734 if (connection->sm_role){ 1735 // slave -> receive master keys 1736 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 1737 } else { 1738 // master -> all done 1739 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1740 sm_done_for_handle(connection->sm_handle); 1741 } 1742 } 1743 return; 1744 case SM_RESPONDER_PH4_LTK_W4_ENC: 1745 reverse_128(data, setup->sm_ltk); 1746 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 1747 log_info_key("ltk", setup->sm_ltk); 1748 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK; 1749 return; 1750 default: 1751 break; 1752 } 1753 } 1754 1755 // note: random generator is ready. this doesn NOT imply that aes engine is unused! 1756 static void sm_handle_random_result(uint8_t * data){ 1757 1758 switch (rau_state){ 1759 case RAU_W4_RANDOM: 1760 // non-resolvable vs. resolvable 1761 switch (gap_random_adress_type){ 1762 case GAP_RANDOM_ADDRESS_RESOLVABLE: 1763 // resolvable: use random as prand and calc address hash 1764 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 1765 memcpy(sm_random_address, data, 3); 1766 sm_random_address[0] &= 0x3f; 1767 sm_random_address[0] |= 0x40; 1768 rau_state = RAU_GET_ENC; 1769 break; 1770 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 1771 default: 1772 // "The two most significant bits of the address shall be equal to ‘0’"" 1773 memcpy(sm_random_address, data, 6); 1774 sm_random_address[0] &= 0x3f; 1775 rau_state = RAU_SET_ADDRESS; 1776 break; 1777 } 1778 return; 1779 default: 1780 break; 1781 } 1782 1783 // retrieve sm_connection provided to sm_random_start 1784 sm_connection_t * connection = (sm_connection_t *) sm_random_context; 1785 if (!connection) return; 1786 switch (connection->sm_engine_state){ 1787 case SM_PH2_W4_RANDOM_TK: 1788 { 1789 // map random to 0-999999 without speding much cycles on a modulus operation 1790 uint32_t tk = little_endian_read_32(data,0); 1791 tk = tk & 0xfffff; // 1048575 1792 if (tk >= 999999){ 1793 tk = tk - 999999; 1794 } 1795 sm_reset_tk(); 1796 big_endian_store_32(setup->sm_tk, 12, tk); 1797 if (connection->sm_role){ 1798 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 1799 } else { 1800 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 1801 sm_trigger_user_response(connection); 1802 // response_idle == nothing <--> sm_trigger_user_response() did not require response 1803 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 1804 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 1805 } 1806 } 1807 return; 1808 } 1809 case SM_PH2_C1_W4_RANDOM_A: 1810 memcpy(&setup->sm_local_random[0], data, 8); // random endinaness 1811 connection->sm_engine_state = SM_PH2_C1_GET_RANDOM_B; 1812 return; 1813 case SM_PH2_C1_W4_RANDOM_B: 1814 memcpy(&setup->sm_local_random[8], data, 8); // random endinaness 1815 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 1816 return; 1817 case SM_PH3_W4_RANDOM: 1818 reverse_64(data, setup->sm_local_rand); 1819 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1820 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xf0) + (connection->sm_actual_encryption_key_size - 1); 1821 // no db for authenticated flag hack: store flag in bit 4 of LSB 1822 setup->sm_local_rand[7] = (setup->sm_local_rand[7] & 0xef) + (connection->sm_connection_authenticated << 4); 1823 connection->sm_engine_state = SM_PH3_GET_DIV; 1824 return; 1825 case SM_PH3_W4_DIV: 1826 // use 16 bit from random value as div 1827 setup->sm_local_div = big_endian_read_16(data, 0); 1828 log_info_hex16("div", setup->sm_local_div); 1829 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 1830 return; 1831 default: 1832 break; 1833 } 1834 } 1835 1836 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 1837 1838 sm_connection_t * sm_conn; 1839 hci_con_handle_t con_handle; 1840 1841 switch (packet_type) { 1842 1843 case HCI_EVENT_PACKET: 1844 switch (hci_event_packet_get_type(packet)) { 1845 1846 case BTSTACK_EVENT_STATE: 1847 // bt stack activated, get started 1848 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 1849 log_info("HCI Working!"); 1850 dkg_state = sm_persistent_irk_ready ? DKG_CALC_DHK : DKG_CALC_IRK; 1851 rau_state = RAU_IDLE; 1852 sm_run(); 1853 } 1854 break; 1855 1856 case HCI_EVENT_LE_META: 1857 switch (packet[2]) { 1858 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 1859 1860 log_info("sm: connected"); 1861 1862 if (packet[3]) return; // connection failed 1863 1864 con_handle = little_endian_read_16(packet, 4); 1865 sm_conn = sm_get_connection_for_handle(con_handle); 1866 if (!sm_conn) break; 1867 1868 sm_conn->sm_handle = con_handle; 1869 sm_conn->sm_role = packet[6]; 1870 sm_conn->sm_peer_addr_type = packet[7]; 1871 reverse_bd_addr(&packet[8], 1872 sm_conn->sm_peer_address); 1873 1874 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 1875 1876 // reset security properties 1877 sm_conn->sm_connection_encrypted = 0; 1878 sm_conn->sm_connection_authenticated = 0; 1879 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 1880 sm_conn->sm_le_db_index = -1; 1881 1882 // prepare CSRK lookup (does not involve setup) 1883 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 1884 1885 // just connected -> everything else happens in sm_run() 1886 if (sm_conn->sm_role){ 1887 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 1888 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 1889 if (sm_slave_request_security) { 1890 // request security if requested by app 1891 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1892 } else { 1893 // otherwise, wait for pairing request 1894 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1895 } 1896 } 1897 break; 1898 } else { 1899 // master 1900 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1901 } 1902 break; 1903 1904 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 1905 con_handle = little_endian_read_16(packet, 3); 1906 sm_conn = sm_get_connection_for_handle(con_handle); 1907 if (!sm_conn) break; 1908 1909 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 1910 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 1911 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 1912 break; 1913 } 1914 1915 // assume that we don't have a LTK for ediv == 0 and random == null 1916 if (little_endian_read_16(packet, 13) == 0 && sm_is_null_random(&packet[5])){ 1917 log_info("LTK Request: ediv & random are empty"); 1918 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1919 break; 1920 } 1921 1922 // store rand and ediv 1923 reverse_64(&packet[5], sm_conn->sm_local_rand); 1924 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 1925 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK; 1926 break; 1927 1928 default: 1929 break; 1930 } 1931 break; 1932 1933 case HCI_EVENT_ENCRYPTION_CHANGE: 1934 con_handle = little_endian_read_16(packet, 3); 1935 sm_conn = sm_get_connection_for_handle(con_handle); 1936 if (!sm_conn) break; 1937 1938 sm_conn->sm_connection_encrypted = packet[5]; 1939 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 1940 sm_conn->sm_actual_encryption_key_size); 1941 log_info("event handler, state %u", sm_conn->sm_engine_state); 1942 if (!sm_conn->sm_connection_encrypted) break; 1943 // continue if part of initial pairing 1944 switch (sm_conn->sm_engine_state){ 1945 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 1946 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1947 sm_done_for_handle(sm_conn->sm_handle); 1948 break; 1949 case SM_PH2_W4_CONNECTION_ENCRYPTED: 1950 if (sm_conn->sm_role){ 1951 // slave 1952 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 1953 } else { 1954 // master 1955 if (sm_key_distribution_all_received(sm_conn)){ 1956 // skip receiving keys as there are none 1957 sm_key_distribution_handle_all_received(sm_conn); 1958 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 1959 } else { 1960 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 1961 } 1962 } 1963 break; 1964 default: 1965 break; 1966 } 1967 break; 1968 1969 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 1970 con_handle = little_endian_read_16(packet, 3); 1971 sm_conn = sm_get_connection_for_handle(con_handle); 1972 if (!sm_conn) break; 1973 1974 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 1975 log_info("event handler, state %u", sm_conn->sm_engine_state); 1976 // continue if part of initial pairing 1977 switch (sm_conn->sm_engine_state){ 1978 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 1979 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1980 sm_done_for_handle(sm_conn->sm_handle); 1981 break; 1982 case SM_PH2_W4_CONNECTION_ENCRYPTED: 1983 if (sm_conn->sm_role){ 1984 // slave 1985 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 1986 } else { 1987 // master 1988 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 1989 } 1990 break; 1991 default: 1992 break; 1993 } 1994 break; 1995 1996 1997 case HCI_EVENT_DISCONNECTION_COMPLETE: 1998 con_handle = little_endian_read_16(packet, 3); 1999 sm_done_for_handle(con_handle); 2000 sm_conn = sm_get_connection_for_handle(con_handle); 2001 if (!sm_conn) break; 2002 2003 // delete stored bonding on disconnect with authentication failure in ph0 2004 if (sm_conn->sm_role == 0 2005 && sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED 2006 && packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE){ 2007 le_device_db_remove(sm_conn->sm_le_db_index); 2008 } 2009 2010 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 2011 sm_conn->sm_handle = 0; 2012 break; 2013 2014 case HCI_EVENT_COMMAND_COMPLETE: 2015 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_encrypt)){ 2016 sm_handle_encryption_result(&packet[6]); 2017 break; 2018 } 2019 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_le_rand)){ 2020 sm_handle_random_result(&packet[6]); 2021 break; 2022 } 2023 break; 2024 default: 2025 break; 2026 } 2027 break; 2028 default: 2029 break; 2030 } 2031 2032 sm_run(); 2033 } 2034 2035 static inline int sm_calc_actual_encryption_key_size(int other){ 2036 if (other < sm_min_encryption_key_size) return 0; 2037 if (other < sm_max_encryption_key_size) return other; 2038 return sm_max_encryption_key_size; 2039 } 2040 2041 /** 2042 * @return ok 2043 */ 2044 static int sm_validate_stk_generation_method(void){ 2045 // check if STK generation method is acceptable by client 2046 switch (setup->sm_stk_generation_method){ 2047 case JUST_WORKS: 2048 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0; 2049 case PK_RESP_INPUT: 2050 case PK_INIT_INPUT: 2051 case OK_BOTH_INPUT: 2052 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0; 2053 case OOB: 2054 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0; 2055 default: 2056 return 0; 2057 } 2058 } 2059 2060 // helper for sm_pdu_handler, calls sm_run on exit 2061 static void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 2062 setup->sm_pairing_failed_reason = SM_REASON_UNSPECIFIED_REASON; 2063 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2064 sm_done_for_handle(sm_conn->sm_handle); 2065 } 2066 2067 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 2068 2069 if (packet_type == HCI_EVENT_PACKET && packet[0] == L2CAP_EVENT_CAN_SEND_NOW){ 2070 sm_run(); 2071 } 2072 2073 if (packet_type != SM_DATA_PACKET) return; 2074 2075 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2076 if (!sm_conn) return; 2077 2078 if (packet[0] == SM_CODE_PAIRING_FAILED){ 2079 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2080 return; 2081 } 2082 2083 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, packet[0]); 2084 2085 int err; 2086 2087 switch (sm_conn->sm_engine_state){ 2088 2089 // a sm timeout requries a new physical connection 2090 case SM_GENERAL_TIMEOUT: 2091 return; 2092 2093 // Initiator 2094 case SM_INITIATOR_CONNECTED: 2095 if ((packet[0] != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 2096 sm_pdu_received_in_wrong_state(sm_conn); 2097 break; 2098 } 2099 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_FAILED){ 2100 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2101 break; 2102 } 2103 if (sm_conn->sm_irk_lookup_state == IRK_LOOKUP_SUCCEEDED){ 2104 uint16_t ediv; 2105 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 2106 if (ediv){ 2107 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 2108 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 2109 } else { 2110 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2111 } 2112 break; 2113 } 2114 // otherwise, store security request 2115 sm_conn->sm_security_request_received = 1; 2116 break; 2117 2118 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 2119 if (packet[0] != SM_CODE_PAIRING_RESPONSE){ 2120 sm_pdu_received_in_wrong_state(sm_conn); 2121 break; 2122 } 2123 // store pairing request 2124 memcpy(&setup->sm_s_pres, packet, sizeof(sm_pairing_packet_t)); 2125 err = sm_stk_generation_init(sm_conn); 2126 if (err){ 2127 setup->sm_pairing_failed_reason = err; 2128 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2129 break; 2130 } 2131 // generate random number first, if we need to show passkey 2132 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 2133 sm_conn->sm_engine_state = SM_PH2_GET_RANDOM_TK; 2134 break; 2135 } 2136 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2137 sm_trigger_user_response(sm_conn); 2138 // response_idle == nothing <--> sm_trigger_user_response() did not require response 2139 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 2140 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2141 } 2142 break; 2143 2144 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 2145 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2146 sm_pdu_received_in_wrong_state(sm_conn); 2147 break; 2148 } 2149 2150 // store s_confirm 2151 reverse_128(&packet[1], setup->sm_peer_confirm); 2152 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2153 break; 2154 2155 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 2156 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2157 sm_pdu_received_in_wrong_state(sm_conn); 2158 break;; 2159 } 2160 2161 // received random value 2162 reverse_128(&packet[1], setup->sm_peer_random); 2163 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2164 break; 2165 2166 // Responder 2167 case SM_RESPONDER_IDLE: 2168 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2169 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 2170 if (packet[0] != SM_CODE_PAIRING_REQUEST){ 2171 sm_pdu_received_in_wrong_state(sm_conn); 2172 break;; 2173 } 2174 2175 // store pairing request 2176 memcpy(&sm_conn->sm_m_preq, packet, sizeof(sm_pairing_packet_t)); 2177 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 2178 break; 2179 2180 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 2181 if (packet[0] != SM_CODE_PAIRING_CONFIRM){ 2182 sm_pdu_received_in_wrong_state(sm_conn); 2183 break;; 2184 } 2185 2186 // received confirm value 2187 reverse_128(&packet[1], setup->sm_peer_confirm); 2188 2189 // notify client to hide shown passkey 2190 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2191 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 2192 } 2193 2194 // handle user cancel pairing? 2195 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 2196 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 2197 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2198 break; 2199 } 2200 2201 // wait for user action? 2202 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 2203 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 2204 break; 2205 } 2206 2207 // calculate and send local_confirm 2208 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2209 break; 2210 2211 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 2212 if (packet[0] != SM_CODE_PAIRING_RANDOM){ 2213 sm_pdu_received_in_wrong_state(sm_conn); 2214 break;; 2215 } 2216 2217 // received random value 2218 reverse_128(&packet[1], setup->sm_peer_random); 2219 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 2220 break; 2221 2222 case SM_PH3_RECEIVE_KEYS: 2223 switch(packet[0]){ 2224 case SM_CODE_ENCRYPTION_INFORMATION: 2225 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2226 reverse_128(&packet[1], setup->sm_peer_ltk); 2227 break; 2228 2229 case SM_CODE_MASTER_IDENTIFICATION: 2230 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2231 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 2232 reverse_64(&packet[3], setup->sm_peer_rand); 2233 break; 2234 2235 case SM_CODE_IDENTITY_INFORMATION: 2236 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2237 reverse_128(&packet[1], setup->sm_peer_irk); 2238 break; 2239 2240 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 2241 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2242 setup->sm_peer_addr_type = packet[1]; 2243 reverse_bd_addr(&packet[2], setup->sm_peer_address); 2244 break; 2245 2246 case SM_CODE_SIGNING_INFORMATION: 2247 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2248 reverse_128(&packet[1], setup->sm_peer_csrk); 2249 break; 2250 default: 2251 // Unexpected PDU 2252 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 2253 break; 2254 } 2255 // done with key distribution? 2256 if (sm_key_distribution_all_received(sm_conn)){ 2257 2258 sm_key_distribution_handle_all_received(sm_conn); 2259 2260 if (sm_conn->sm_role){ 2261 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 2262 sm_done_for_handle(sm_conn->sm_handle); 2263 } else { 2264 sm_conn->sm_engine_state = SM_PH3_GET_RANDOM; 2265 } 2266 } 2267 break; 2268 default: 2269 // Unexpected PDU 2270 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 2271 break; 2272 } 2273 2274 // try to send preparared packet 2275 sm_run(); 2276 } 2277 2278 // Security Manager Client API 2279 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data)){ 2280 sm_get_oob_data = get_oob_data_callback; 2281 } 2282 2283 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 2284 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 2285 } 2286 2287 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 2288 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 2289 } 2290 2291 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 2292 sm_min_encryption_key_size = min_size; 2293 sm_max_encryption_key_size = max_size; 2294 } 2295 2296 void sm_set_authentication_requirements(uint8_t auth_req){ 2297 sm_auth_req = auth_req; 2298 } 2299 2300 void sm_set_io_capabilities(io_capability_t io_capability){ 2301 sm_io_capabilities = io_capability; 2302 } 2303 2304 void sm_set_request_security(int enable){ 2305 sm_slave_request_security = enable; 2306 } 2307 2308 void sm_set_er(sm_key_t er){ 2309 memcpy(sm_persistent_er, er, 16); 2310 } 2311 2312 void sm_set_ir(sm_key_t ir){ 2313 memcpy(sm_persistent_ir, ir, 16); 2314 } 2315 2316 // Testing support only 2317 void sm_test_set_irk(sm_key_t irk){ 2318 memcpy(sm_persistent_irk, irk, 16); 2319 sm_persistent_irk_ready = 1; 2320 } 2321 2322 void sm_test_use_fixed_local_csrk(void){ 2323 test_use_fixed_local_csrk = 1; 2324 } 2325 2326 void sm_init(void){ 2327 // set some (BTstack default) ER and IR 2328 int i; 2329 sm_key_t er; 2330 sm_key_t ir; 2331 for (i=0;i<16;i++){ 2332 er[i] = 0x30 + i; 2333 ir[i] = 0x90 + i; 2334 } 2335 sm_set_er(er); 2336 sm_set_ir(ir); 2337 // defaults 2338 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 2339 | SM_STK_GENERATION_METHOD_OOB 2340 | SM_STK_GENERATION_METHOD_PASSKEY; 2341 sm_max_encryption_key_size = 16; 2342 sm_min_encryption_key_size = 7; 2343 2344 sm_cmac_state = CMAC_IDLE; 2345 dkg_state = DKG_W4_WORKING; 2346 rau_state = RAU_W4_WORKING; 2347 sm_aes128_state = SM_AES128_IDLE; 2348 sm_address_resolution_test = -1; // no private address to resolve yet 2349 sm_address_resolution_ah_calculation_active = 0; 2350 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 2351 sm_address_resolution_general_queue = NULL; 2352 2353 gap_random_adress_update_period = 15 * 60 * 1000L; 2354 2355 sm_active_connection = 0; 2356 2357 test_use_fixed_local_csrk = 0; 2358 2359 // register for HCI Events from HCI 2360 hci_event_callback_registration.callback = &sm_event_packet_handler; 2361 hci_add_event_handler(&hci_event_callback_registration); 2362 2363 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 2364 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2365 } 2366 2367 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 2368 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 2369 if (!hci_con) return NULL; 2370 return &hci_con->sm_connection; 2371 } 2372 2373 // @returns 0 if not encrypted, 7-16 otherwise 2374 int sm_encryption_key_size(hci_con_handle_t con_handle){ 2375 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2376 if (!sm_conn) return 0; // wrong connection 2377 if (!sm_conn->sm_connection_encrypted) return 0; 2378 return sm_conn->sm_actual_encryption_key_size; 2379 } 2380 2381 int sm_authenticated(hci_con_handle_t con_handle){ 2382 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2383 if (!sm_conn) return 0; // wrong connection 2384 if (!sm_conn->sm_connection_encrypted) return 0; // unencrypted connection cannot be authenticated 2385 return sm_conn->sm_connection_authenticated; 2386 } 2387 2388 authorization_state_t sm_authorization_state(hci_con_handle_t con_handle){ 2389 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2390 if (!sm_conn) return AUTHORIZATION_UNKNOWN; // wrong connection 2391 if (!sm_conn->sm_connection_encrypted) return AUTHORIZATION_UNKNOWN; // unencrypted connection cannot be authorized 2392 if (!sm_conn->sm_connection_authenticated) return AUTHORIZATION_UNKNOWN; // unauthenticatd connection cannot be authorized 2393 return sm_conn->sm_connection_authorization_state; 2394 } 2395 2396 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 2397 switch (sm_conn->sm_engine_state){ 2398 case SM_GENERAL_IDLE: 2399 case SM_RESPONDER_IDLE: 2400 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 2401 sm_run(); 2402 break; 2403 default: 2404 break; 2405 } 2406 } 2407 2408 /** 2409 * @brief Trigger Security Request 2410 */ 2411 void sm_send_security_request(hci_con_handle_t con_handle){ 2412 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2413 if (!sm_conn) return; 2414 sm_send_security_request_for_connection(sm_conn); 2415 } 2416 2417 // request pairing 2418 void sm_request_pairing(hci_con_handle_t con_handle){ 2419 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2420 if (!sm_conn) return; // wrong connection 2421 2422 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 2423 if (sm_conn->sm_role){ 2424 sm_send_security_request_for_connection(sm_conn); 2425 } else { 2426 // used as a trigger to start central/master/initiator security procedures 2427 uint16_t ediv; 2428 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 2429 switch (sm_conn->sm_irk_lookup_state){ 2430 case IRK_LOOKUP_FAILED: 2431 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2432 break; 2433 case IRK_LOOKUP_SUCCEEDED: 2434 le_device_db_encryption_get(sm_conn->sm_le_db_index, &ediv, NULL, NULL, NULL, NULL, NULL); 2435 if (ediv){ 2436 log_info("sm: Setting up previous ltk/ediv/rand for device index %u", sm_conn->sm_le_db_index); 2437 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 2438 } else { 2439 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 2440 } 2441 break; 2442 default: 2443 sm_conn->sm_bonding_requested = 1; 2444 break; 2445 } 2446 } 2447 } 2448 sm_run(); 2449 } 2450 2451 // called by client app on authorization request 2452 void sm_authorization_decline(hci_con_handle_t con_handle){ 2453 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2454 if (!sm_conn) return; // wrong connection 2455 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 2456 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 2457 } 2458 2459 void sm_authorization_grant(hci_con_handle_t con_handle){ 2460 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2461 if (!sm_conn) return; // wrong connection 2462 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 2463 sm_notify_client_authorization(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 2464 } 2465 2466 // GAP Bonding API 2467 2468 void sm_bonding_decline(hci_con_handle_t con_handle){ 2469 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2470 if (!sm_conn) return; // wrong connection 2471 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 2472 2473 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 2474 sm_done_for_handle(sm_conn->sm_handle); 2475 setup->sm_pairing_failed_reason = SM_REASON_PASSKEYT_ENTRY_FAILED; 2476 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2477 } 2478 sm_run(); 2479 } 2480 2481 void sm_just_works_confirm(hci_con_handle_t con_handle){ 2482 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2483 if (!sm_conn) return; // wrong connection 2484 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 2485 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 2486 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2487 } 2488 sm_run(); 2489 } 2490 2491 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 2492 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2493 if (!sm_conn) return; // wrong connection 2494 sm_reset_tk(); 2495 big_endian_store_32(setup->sm_tk, 12, passkey); 2496 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 2497 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 2498 sm_conn->sm_engine_state = SM_PH2_C1_GET_RANDOM_A; 2499 } 2500 sm_run(); 2501 } 2502 2503 /** 2504 * @brief Identify device in LE Device DB 2505 * @param handle 2506 * @returns index from le_device_db or -1 if not found/identified 2507 */ 2508 int sm_le_device_index(hci_con_handle_t con_handle ){ 2509 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 2510 if (!sm_conn) return -1; 2511 return sm_conn->sm_le_db_index; 2512 } 2513 2514 // GAP LE API 2515 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 2516 gap_random_address_update_stop(); 2517 gap_random_adress_type = random_address_type; 2518 if (random_address_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 2519 gap_random_address_update_start(); 2520 gap_random_address_trigger(); 2521 } 2522 2523 gap_random_address_type_t gap_random_address_get_mode(void){ 2524 return gap_random_adress_type; 2525 } 2526 2527 void gap_random_address_set_update_period(int period_ms){ 2528 gap_random_adress_update_period = period_ms; 2529 if (gap_random_adress_type == GAP_RANDOM_ADDRESS_TYPE_OFF) return; 2530 gap_random_address_update_stop(); 2531 gap_random_address_update_start(); 2532 } 2533 2534 void gap_random_address_set(bd_addr_t addr){ 2535 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_OFF); 2536 memcpy(sm_random_address, addr, 6); 2537 rau_state = RAU_SET_ADDRESS; 2538 sm_run(); 2539 } 2540 2541 /* 2542 * @brief Set Advertisement Paramters 2543 * @param adv_int_min 2544 * @param adv_int_max 2545 * @param adv_type 2546 * @param direct_address_type 2547 * @param direct_address 2548 * @param channel_map 2549 * @param filter_policy 2550 * 2551 * @note own_address_type is used from gap_random_address_set_mode 2552 */ 2553 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 2554 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 2555 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, gap_random_adress_type, 2556 direct_address_typ, direct_address, channel_map, filter_policy); 2557 } 2558 2559