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 #define BTSTACK_FILE__ "sm.c" 39 40 #include <string.h> 41 #include <inttypes.h> 42 43 #include "ble/le_device_db.h" 44 #include "ble/core.h" 45 #include "ble/sm.h" 46 #include "bluetooth_company_id.h" 47 #include "btstack_bool.h" 48 #include "btstack_crypto.h" 49 #include "btstack_debug.h" 50 #include "btstack_event.h" 51 #include "btstack_linked_list.h" 52 #include "btstack_memory.h" 53 #include "btstack_tlv.h" 54 #include "gap.h" 55 #include "hci.h" 56 #include "hci_dump.h" 57 #include "l2cap.h" 58 59 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) 60 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." 61 #endif 62 63 #if defined(ENABLE_CROSS_TRANSPORT_KEY_DERIVATION) && (!defined(ENABLE_CLASSIC) || !defined(ENABLE_LE_SECURE_CONNECTIONS)) 64 #error "Cross Transport Key Derivation requires support for LE Secure Connections and BR/EDR (Classic)" 65 #endif 66 67 // assert SM Public Key can be sent/received 68 #ifdef ENABLE_LE_SECURE_CONNECTIONS 69 #if HCI_ACL_PAYLOAD_SIZE < 69 70 #error "HCI_ACL_PAYLOAD_SIZE must be at least 69 bytes when using LE Secure Conection. Please increase HCI_ACL_PAYLOAD_SIZE or disable ENABLE_LE_SECURE_CONNECTIONS" 71 #endif 72 #endif 73 74 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) 75 #define IS_RESPONDER(role) (role) 76 #else 77 #ifdef ENABLE_LE_CENTRAL 78 // only central - never responder (avoid 'unused variable' warnings) 79 #define IS_RESPONDER(role) (0 && role) 80 #else 81 // only peripheral - always responder (avoid 'unused variable' warnings) 82 #define IS_RESPONDER(role) (1 || role) 83 #endif 84 #endif 85 86 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 87 #define USE_CMAC_ENGINE 88 #endif 89 90 91 #define BTSTACK_TAG32(A,B,C,D) (((A) << 24) | ((B) << 16) | ((C) << 8) | (D)) 92 93 // 94 // SM internal types and globals 95 // 96 97 typedef enum { 98 DKG_W4_WORKING, 99 DKG_CALC_IRK, 100 DKG_CALC_DHK, 101 DKG_READY 102 } derived_key_generation_t; 103 104 typedef enum { 105 RAU_IDLE, 106 RAU_GET_RANDOM, 107 RAU_W4_RANDOM, 108 RAU_GET_ENC, 109 RAU_W4_ENC, 110 RAU_SET_ADDRESS, 111 } random_address_update_t; 112 113 typedef enum { 114 CMAC_IDLE, 115 CMAC_CALC_SUBKEYS, 116 CMAC_W4_SUBKEYS, 117 CMAC_CALC_MI, 118 CMAC_W4_MI, 119 CMAC_CALC_MLAST, 120 CMAC_W4_MLAST 121 } cmac_state_t; 122 123 typedef enum { 124 JUST_WORKS, 125 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 126 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 127 PK_BOTH_INPUT, // Only input on both, both input PK 128 NUMERIC_COMPARISON, // Only numerical compparison (yes/no) on on both sides 129 OOB // OOB available on one (SC) or both sides (legacy) 130 } stk_generation_method_t; 131 132 typedef enum { 133 SM_USER_RESPONSE_IDLE, 134 SM_USER_RESPONSE_PENDING, 135 SM_USER_RESPONSE_CONFIRM, 136 SM_USER_RESPONSE_PASSKEY, 137 SM_USER_RESPONSE_DECLINE 138 } sm_user_response_t; 139 140 typedef enum { 141 SM_AES128_IDLE, 142 SM_AES128_ACTIVE 143 } sm_aes128_state_t; 144 145 typedef enum { 146 ADDRESS_RESOLUTION_IDLE, 147 ADDRESS_RESOLUTION_GENERAL, 148 ADDRESS_RESOLUTION_FOR_CONNECTION, 149 } address_resolution_mode_t; 150 151 typedef enum { 152 ADDRESS_RESOLUTION_SUCCEEDED, 153 ADDRESS_RESOLUTION_FAILED, 154 } address_resolution_event_t; 155 156 typedef enum { 157 EC_KEY_GENERATION_IDLE, 158 EC_KEY_GENERATION_ACTIVE, 159 EC_KEY_GENERATION_DONE, 160 } ec_key_generation_state_t; 161 162 typedef enum { 163 SM_STATE_VAR_DHKEY_NEEDED = 1 << 0, 164 SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1, 165 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2, 166 } sm_state_var_t; 167 168 typedef enum { 169 SM_SC_OOB_IDLE, 170 SM_SC_OOB_W4_RANDOM, 171 SM_SC_OOB_W2_CALC_CONFIRM, 172 SM_SC_OOB_W4_CONFIRM, 173 } sm_sc_oob_state_t; 174 175 typedef uint8_t sm_key24_t[3]; 176 typedef uint8_t sm_key56_t[7]; 177 typedef uint8_t sm_key256_t[32]; 178 179 // 180 // GLOBAL DATA 181 // 182 183 static bool test_use_fixed_local_csrk; 184 static bool test_use_fixed_local_irk; 185 186 #ifdef ENABLE_TESTING_SUPPORT 187 static uint8_t test_pairing_failure; 188 #endif 189 190 // configuration 191 static uint8_t sm_accepted_stk_generation_methods; 192 static uint8_t sm_max_encryption_key_size; 193 static uint8_t sm_min_encryption_key_size; 194 static uint8_t sm_auth_req = 0; 195 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 196 static uint8_t sm_slave_request_security; 197 static uint32_t sm_fixed_passkey_in_display_role; 198 static uint8_t sm_reconstruct_ltk_without_le_device_db_entry; 199 200 #ifdef ENABLE_LE_SECURE_CONNECTIONS 201 static bool sm_sc_only_mode; 202 static uint8_t sm_sc_oob_random[16]; 203 static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); 204 static sm_sc_oob_state_t sm_sc_oob_state; 205 #endif 206 207 208 static uint8_t sm_persistent_keys_random_active; 209 static const btstack_tlv_t * sm_tlv_impl; 210 static void * sm_tlv_context; 211 212 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 213 static sm_key_t sm_persistent_er; 214 static sm_key_t sm_persistent_ir; 215 216 // derived from sm_persistent_ir 217 static sm_key_t sm_persistent_dhk; 218 static sm_key_t sm_persistent_irk; 219 static derived_key_generation_t dkg_state; 220 221 // derived from sm_persistent_er 222 // .. 223 224 // random address update 225 static random_address_update_t rau_state; 226 static bd_addr_t sm_random_address; 227 228 #ifdef USE_CMAC_ENGINE 229 // CMAC Calculation: General 230 static btstack_crypto_aes128_cmac_t sm_cmac_request; 231 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 232 static uint8_t sm_cmac_active; 233 static uint8_t sm_cmac_hash[16]; 234 #endif 235 236 // CMAC for ATT Signed Writes 237 #ifdef ENABLE_LE_SIGNED_WRITE 238 static uint16_t sm_cmac_signed_write_message_len; 239 static uint8_t sm_cmac_signed_write_header[3]; 240 static const uint8_t * sm_cmac_signed_write_message; 241 static uint8_t sm_cmac_signed_write_sign_counter[4]; 242 #endif 243 244 // CMAC for Secure Connection functions 245 #ifdef ENABLE_LE_SECURE_CONNECTIONS 246 static sm_connection_t * sm_cmac_connection; 247 static uint8_t sm_cmac_sc_buffer[80]; 248 #endif 249 250 // resolvable private address lookup / CSRK calculation 251 static int sm_address_resolution_test; 252 static int sm_address_resolution_ah_calculation_active; 253 static uint8_t sm_address_resolution_addr_type; 254 static bd_addr_t sm_address_resolution_address; 255 static void * sm_address_resolution_context; 256 static address_resolution_mode_t sm_address_resolution_mode; 257 static btstack_linked_list_t sm_address_resolution_general_queue; 258 259 // aes128 crypto engine. 260 static sm_aes128_state_t sm_aes128_state; 261 262 // crypto 263 static btstack_crypto_random_t sm_crypto_random_request; 264 static btstack_crypto_aes128_t sm_crypto_aes128_request; 265 #ifdef ENABLE_LE_SECURE_CONNECTIONS 266 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 267 #endif 268 269 // temp storage for random data 270 static uint8_t sm_random_data[8]; 271 static uint8_t sm_aes128_key[16]; 272 static uint8_t sm_aes128_plaintext[16]; 273 static uint8_t sm_aes128_ciphertext[16]; 274 275 // to receive hci events 276 static btstack_packet_callback_registration_t hci_event_callback_registration; 277 278 /* to dispatch sm event */ 279 static btstack_linked_list_t sm_event_handlers; 280 281 /* to schedule calls to sm_run */ 282 static btstack_timer_source_t sm_run_timer; 283 284 // LE Secure Connections 285 #ifdef ENABLE_LE_SECURE_CONNECTIONS 286 static ec_key_generation_state_t ec_key_generation_state; 287 static uint8_t ec_q[64]; 288 #endif 289 290 // 291 // Volume 3, Part H, Chapter 24 292 // "Security shall be initiated by the Security Manager in the device in the master role. 293 // The device in the slave role shall be the responding device." 294 // -> master := initiator, slave := responder 295 // 296 297 // data needed for security setup 298 typedef struct sm_setup_context { 299 300 btstack_timer_source_t sm_timeout; 301 302 // used in all phases 303 uint8_t sm_pairing_failed_reason; 304 305 // user response, (Phase 1 and/or 2) 306 uint8_t sm_user_response; 307 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 308 309 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 310 uint8_t sm_key_distribution_send_set; 311 uint8_t sm_key_distribution_sent_set; 312 uint8_t sm_key_distribution_received_set; 313 314 // Phase 2 (Pairing over SMP) 315 stk_generation_method_t sm_stk_generation_method; 316 sm_key_t sm_tk; 317 uint8_t sm_have_oob_data; 318 uint8_t sm_use_secure_connections; 319 320 sm_key_t sm_c1_t3_value; // c1 calculation 321 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 322 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 323 sm_key_t sm_local_random; 324 sm_key_t sm_local_confirm; 325 sm_key_t sm_peer_random; 326 sm_key_t sm_peer_confirm; 327 uint8_t sm_m_addr_type; // address and type can be removed 328 uint8_t sm_s_addr_type; // '' 329 bd_addr_t sm_m_address; // '' 330 bd_addr_t sm_s_address; // '' 331 sm_key_t sm_ltk; 332 333 uint8_t sm_state_vars; 334 #ifdef ENABLE_LE_SECURE_CONNECTIONS 335 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 336 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 337 sm_key_t sm_local_nonce; // might be combined with sm_local_random 338 uint8_t sm_dhkey[32]; 339 sm_key_t sm_peer_dhkey_check; 340 sm_key_t sm_local_dhkey_check; 341 sm_key_t sm_ra; 342 sm_key_t sm_rb; 343 sm_key_t sm_t; // used for f5 and h6 344 sm_key_t sm_mackey; 345 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 346 #endif 347 348 // Phase 3 349 350 // key distribution, we generate 351 uint16_t sm_local_y; 352 uint16_t sm_local_div; 353 uint16_t sm_local_ediv; 354 uint8_t sm_local_rand[8]; 355 sm_key_t sm_local_ltk; 356 sm_key_t sm_local_csrk; 357 sm_key_t sm_local_irk; 358 // sm_local_address/addr_type not needed 359 360 // key distribution, received from peer 361 uint16_t sm_peer_y; 362 uint16_t sm_peer_div; 363 uint16_t sm_peer_ediv; 364 uint8_t sm_peer_rand[8]; 365 sm_key_t sm_peer_ltk; 366 sm_key_t sm_peer_irk; 367 sm_key_t sm_peer_csrk; 368 uint8_t sm_peer_addr_type; 369 bd_addr_t sm_peer_address; 370 #ifdef ENABLE_LE_SIGNED_WRITE 371 int sm_le_device_index; 372 #endif 373 } sm_setup_context_t; 374 375 // 376 static sm_setup_context_t the_setup; 377 static sm_setup_context_t * setup = &the_setup; 378 379 // active connection - the one for which the_setup is used for 380 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 381 382 // @returns 1 if oob data is available 383 // stores oob data in provided 16 byte buffer if not null 384 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 385 static int (*sm_get_sc_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_sc_peer_confirm, uint8_t * oob_sc_peer_random); 386 387 static void sm_run(void); 388 static void sm_done_for_handle(hci_con_handle_t con_handle); 389 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 390 static inline int sm_calc_actual_encryption_key_size(int other); 391 static int sm_validate_stk_generation_method(void); 392 static void sm_handle_encryption_result_address_resolution(void *arg); 393 static void sm_handle_encryption_result_dkg_dhk(void *arg); 394 static void sm_handle_encryption_result_dkg_irk(void *arg); 395 static void sm_handle_encryption_result_enc_a(void *arg); 396 static void sm_handle_encryption_result_enc_b(void *arg); 397 static void sm_handle_encryption_result_enc_c(void *arg); 398 static void sm_handle_encryption_result_enc_csrk(void *arg); 399 static void sm_handle_encryption_result_enc_d(void * arg); 400 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 401 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 402 #ifdef ENABLE_LE_PERIPHERAL 403 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 404 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 405 #endif 406 static void sm_handle_encryption_result_enc_stk(void *arg); 407 static void sm_handle_encryption_result_rau(void *arg); 408 static void sm_handle_random_result_ph2_tk(void * arg); 409 static void sm_handle_random_result_rau(void * arg); 410 #ifdef ENABLE_LE_SECURE_CONNECTIONS 411 static void sm_cmac_message_start(const sm_key_t key, uint16_t message_len, const uint8_t * message, void (*done_callback)(uint8_t * hash)); 412 static void sm_ec_generate_new_key(void); 413 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg); 414 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); 415 static int sm_passkey_entry(stk_generation_method_t method); 416 #endif 417 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 418 419 static void log_info_hex16(const char * name, uint16_t value){ 420 log_info("%-6s 0x%04x", name, value); 421 } 422 423 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 424 // return packet[0]; 425 // } 426 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 427 return packet[1]; 428 } 429 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 430 return packet[2]; 431 } 432 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 433 return packet[3]; 434 } 435 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 436 return packet[4]; 437 } 438 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 439 return packet[5]; 440 } 441 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 442 return packet[6]; 443 } 444 445 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 446 packet[0] = code; 447 } 448 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 449 packet[1] = io_capability; 450 } 451 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 452 packet[2] = oob_data_flag; 453 } 454 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 455 packet[3] = auth_req; 456 } 457 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 458 packet[4] = max_encryption_key_size; 459 } 460 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 461 packet[5] = initiator_key_distribution; 462 } 463 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 464 packet[6] = responder_key_distribution; 465 } 466 467 // @returns 1 if all bytes are 0 468 static int sm_is_null(uint8_t * data, int size){ 469 int i; 470 for (i=0; i < size ; i++){ 471 if (data[i] != 0) { 472 return 0; 473 } 474 } 475 return 1; 476 } 477 478 static int sm_is_null_random(uint8_t random[8]){ 479 return sm_is_null(random, 8); 480 } 481 482 static int sm_is_null_key(uint8_t * key){ 483 return sm_is_null(key, 16); 484 } 485 486 // sm_trigger_run allows to schedule callback from main run loop // reduces stack depth 487 static void sm_run_timer_handler(btstack_timer_source_t * ts){ 488 UNUSED(ts); 489 sm_run(); 490 } 491 static void sm_trigger_run(void){ 492 (void)btstack_run_loop_remove_timer(&sm_run_timer); 493 btstack_run_loop_set_timer(&sm_run_timer, 0); 494 btstack_run_loop_add_timer(&sm_run_timer); 495 } 496 497 // Key utils 498 static void sm_reset_tk(void){ 499 int i; 500 for (i=0;i<16;i++){ 501 setup->sm_tk[i] = 0; 502 } 503 } 504 505 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 506 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 507 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 508 int i; 509 for (i = max_encryption_size ; i < 16 ; i++){ 510 key[15-i] = 0; 511 } 512 } 513 514 // ER / IR checks 515 static void sm_er_ir_set_default(void){ 516 int i; 517 for (i=0;i<16;i++){ 518 sm_persistent_er[i] = 0x30 + i; 519 sm_persistent_ir[i] = 0x90 + i; 520 } 521 } 522 523 static int sm_er_is_default(void){ 524 int i; 525 for (i=0;i<16;i++){ 526 if (sm_persistent_er[i] != (0x30+i)) return 0; 527 } 528 return 1; 529 } 530 531 static int sm_ir_is_default(void){ 532 int i; 533 for (i=0;i<16;i++){ 534 if (sm_persistent_ir[i] != (0x90+i)) return 0; 535 } 536 return 1; 537 } 538 539 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 540 UNUSED(channel); 541 542 // log event 543 hci_dump_packet(packet_type, 1, packet, size); 544 // dispatch to all event handlers 545 btstack_linked_list_iterator_t it; 546 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 547 while (btstack_linked_list_iterator_has_next(&it)){ 548 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 549 entry->callback(packet_type, 0, packet, size); 550 } 551 } 552 553 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){ 554 event[0] = type; 555 event[1] = event_size - 2; 556 little_endian_store_16(event, 2, con_handle); 557 event[4] = addr_type; 558 reverse_bd_addr(address, &event[5]); 559 } 560 561 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 562 uint8_t event[11]; 563 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 564 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 565 } 566 567 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){ 568 uint8_t event[15]; 569 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 570 little_endian_store_32(event, 11, passkey); 571 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 572 } 573 574 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){ 575 // fetch addr and addr type from db, only called for valid entries 576 bd_addr_t identity_address; 577 int identity_address_type; 578 le_device_db_info(index, &identity_address_type, identity_address, NULL); 579 580 uint8_t event[20]; 581 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 582 event[11] = identity_address_type; 583 reverse_bd_addr(identity_address, &event[12]); 584 little_endian_store_16(event, 18, index); 585 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 586 } 587 588 static void sm_notify_client_status(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint8_t status){ 589 uint8_t event[12]; 590 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 591 event[11] = status; 592 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 593 } 594 595 596 static void sm_reencryption_started(sm_connection_t * sm_conn){ 597 598 if (sm_conn->sm_reencryption_active) return; 599 600 sm_conn->sm_reencryption_active = true; 601 602 // fetch addr and addr type from db, only called for valid entries 603 int identity_addr_type; 604 bd_addr_t identity_addr; 605 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 606 607 sm_notify_client_base(SM_EVENT_REENCRYPTION_STARTED, sm_conn->sm_handle, identity_addr_type, identity_addr); 608 } 609 610 static void sm_reencryption_complete(sm_connection_t * sm_conn, uint8_t status){ 611 612 sm_conn->sm_reencryption_active = false; 613 614 // fetch addr and addr type from db, only called for valid entries 615 int identity_addr_type; 616 bd_addr_t identity_addr; 617 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 618 619 sm_notify_client_status(SM_EVENT_REENCRYPTION_COMPLETE, sm_conn->sm_handle, identity_addr_type, identity_addr, status); 620 } 621 622 static void sm_pairing_complete(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 623 624 if (sm_conn->sm_reencryption_active){ 625 sm_reencryption_complete(sm_conn, status); 626 } 627 628 uint8_t event[13]; 629 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 630 event[11] = status; 631 event[12] = reason; 632 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 633 } 634 635 // SMP Timeout implementation 636 637 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 638 // the Security Manager Timer shall be reset and started. 639 // 640 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 641 // 642 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 643 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 644 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 645 // established. 646 647 static void sm_timeout_handler(btstack_timer_source_t * timer){ 648 log_info("SM timeout"); 649 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 650 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 651 sm_pairing_complete(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 652 sm_done_for_handle(sm_conn->sm_handle); 653 654 // trigger handling of next ready connection 655 sm_run(); 656 } 657 static void sm_timeout_start(sm_connection_t * sm_conn){ 658 btstack_run_loop_remove_timer(&setup->sm_timeout); 659 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 660 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 661 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 662 btstack_run_loop_add_timer(&setup->sm_timeout); 663 } 664 static void sm_timeout_stop(void){ 665 btstack_run_loop_remove_timer(&setup->sm_timeout); 666 } 667 static void sm_timeout_reset(sm_connection_t * sm_conn){ 668 sm_timeout_stop(); 669 sm_timeout_start(sm_conn); 670 } 671 672 // end of sm timeout 673 674 // GAP Random Address updates 675 static gap_random_address_type_t gap_random_adress_type; 676 static btstack_timer_source_t gap_random_address_update_timer; 677 static uint32_t gap_random_adress_update_period; 678 679 static void gap_random_address_trigger(void){ 680 log_info("gap_random_address_trigger, state %u", rau_state); 681 if (rau_state != RAU_IDLE) return; 682 rau_state = RAU_GET_RANDOM; 683 sm_trigger_run(); 684 } 685 686 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 687 UNUSED(timer); 688 689 log_info("GAP Random Address Update due"); 690 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 691 btstack_run_loop_add_timer(&gap_random_address_update_timer); 692 gap_random_address_trigger(); 693 } 694 695 static void gap_random_address_update_start(void){ 696 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 697 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 698 btstack_run_loop_add_timer(&gap_random_address_update_timer); 699 } 700 701 static void gap_random_address_update_stop(void){ 702 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 703 } 704 705 // ah(k,r) helper 706 // r = padding || r 707 // r - 24 bit value 708 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 709 // r'= padding || r 710 memset(r_prime, 0, 16); 711 (void)memcpy(&r_prime[13], r, 3); 712 } 713 714 // d1 helper 715 // d' = padding || r || d 716 // d,r - 16 bit values 717 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 718 // d'= padding || r || d 719 memset(d1_prime, 0, 16); 720 big_endian_store_16(d1_prime, 12, r); 721 big_endian_store_16(d1_prime, 14, d); 722 } 723 724 // calculate arguments for first AES128 operation in C1 function 725 static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, uint8_t * t1){ 726 727 // p1 = pres || preq || rat’ || iat’ 728 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 729 // cant octet of pres becomes the most significant octet of p1. 730 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 731 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 732 // p1 is 0x05000800000302070710000001010001." 733 734 sm_key_t p1; 735 reverse_56(pres, &p1[0]); 736 reverse_56(preq, &p1[7]); 737 p1[14] = rat; 738 p1[15] = iat; 739 log_info_key("p1", p1); 740 log_info_key("r", r); 741 742 // t1 = r xor p1 743 int i; 744 for (i=0;i<16;i++){ 745 t1[i] = r[i] ^ p1[i]; 746 } 747 log_info_key("t1", t1); 748 } 749 750 // calculate arguments for second AES128 operation in C1 function 751 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 752 // p2 = padding || ia || ra 753 // "The least significant octet of ra becomes the least significant octet of p2 and 754 // the most significant octet of padding becomes the most significant octet of p2. 755 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 756 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 757 758 sm_key_t p2; 759 memset(p2, 0, 16); 760 (void)memcpy(&p2[4], ia, 6); 761 (void)memcpy(&p2[10], ra, 6); 762 log_info_key("p2", p2); 763 764 // c1 = e(k, t2_xor_p2) 765 int i; 766 for (i=0;i<16;i++){ 767 t3[i] = t2[i] ^ p2[i]; 768 } 769 log_info_key("t3", t3); 770 } 771 772 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 773 log_info_key("r1", r1); 774 log_info_key("r2", r2); 775 (void)memcpy(&r_prime[8], &r2[8], 8); 776 (void)memcpy(&r_prime[0], &r1[8], 8); 777 } 778 779 780 // decide on stk generation based on 781 // - pairing request 782 // - io capabilities 783 // - OOB data availability 784 static void sm_setup_tk(void){ 785 786 // horizontal: initiator capabilities 787 // vertial: responder capabilities 788 static const stk_generation_method_t stk_generation_method [5] [5] = { 789 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 790 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 791 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 792 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 793 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 794 }; 795 796 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 797 #ifdef ENABLE_LE_SECURE_CONNECTIONS 798 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 799 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 800 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 801 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 802 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 803 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 804 }; 805 #endif 806 807 // default: just works 808 setup->sm_stk_generation_method = JUST_WORKS; 809 810 #ifdef ENABLE_LE_SECURE_CONNECTIONS 811 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 812 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 813 & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; 814 #else 815 setup->sm_use_secure_connections = 0; 816 #endif 817 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 818 819 820 // decide if OOB will be used based on SC vs. Legacy and oob flags 821 int use_oob = 0; 822 if (setup->sm_use_secure_connections){ 823 // In LE Secure Connections pairing, the out of band method is used if at least 824 // one device has the peer device's out of band authentication data available. 825 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 826 } else { 827 // In LE legacy pairing, the out of band method is used if both the devices have 828 // the other device's out of band authentication data available. 829 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 830 } 831 if (use_oob){ 832 log_info("SM: have OOB data"); 833 log_info_key("OOB", setup->sm_tk); 834 setup->sm_stk_generation_method = OOB; 835 return; 836 } 837 838 // If both devices have not set the MITM option in the Authentication Requirements 839 // Flags, then the IO capabilities shall be ignored and the Just Works association 840 // model shall be used. 841 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) 842 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ 843 log_info("SM: MITM not required by both -> JUST WORKS"); 844 return; 845 } 846 847 // Reset TK as it has been setup in sm_init_setup 848 sm_reset_tk(); 849 850 // Also use just works if unknown io capabilites 851 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)){ 852 return; 853 } 854 855 // Otherwise the IO capabilities of the devices shall be used to determine the 856 // pairing method as defined in Table 2.4. 857 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 858 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 859 860 #ifdef ENABLE_LE_SECURE_CONNECTIONS 861 // table not define by default 862 if (setup->sm_use_secure_connections){ 863 generation_method = stk_generation_method_with_secure_connection; 864 } 865 #endif 866 setup->sm_stk_generation_method = generation_method[sm_pairing_packet_get_io_capability(setup->sm_s_pres)][sm_pairing_packet_get_io_capability(setup->sm_m_preq)]; 867 868 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 869 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); 870 } 871 872 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 873 int flags = 0; 874 if (key_set & SM_KEYDIST_ENC_KEY){ 875 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 876 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 877 } 878 if (key_set & SM_KEYDIST_ID_KEY){ 879 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 880 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 881 } 882 if (key_set & SM_KEYDIST_SIGN){ 883 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 884 } 885 return flags; 886 } 887 888 static void sm_setup_key_distribution(uint8_t key_set){ 889 setup->sm_key_distribution_received_set = 0; 890 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 891 setup->sm_key_distribution_sent_set = 0; 892 #ifdef ENABLE_LE_SIGNED_WRITE 893 setup->sm_le_device_index = -1; 894 #endif 895 } 896 897 // CSRK Key Lookup 898 899 900 static int sm_address_resolution_idle(void){ 901 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 902 } 903 904 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){ 905 (void)memcpy(sm_address_resolution_address, addr, 6); 906 sm_address_resolution_addr_type = addr_type; 907 sm_address_resolution_test = 0; 908 sm_address_resolution_mode = mode; 909 sm_address_resolution_context = context; 910 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 911 } 912 913 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 914 // check if already in list 915 btstack_linked_list_iterator_t it; 916 sm_lookup_entry_t * entry; 917 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 918 while(btstack_linked_list_iterator_has_next(&it)){ 919 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 920 if (entry->address_type != address_type) continue; 921 if (memcmp(entry->address, address, 6)) continue; 922 // already in list 923 return BTSTACK_BUSY; 924 } 925 entry = btstack_memory_sm_lookup_entry_get(); 926 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 927 entry->address_type = (bd_addr_type_t) address_type; 928 (void)memcpy(entry->address, address, 6); 929 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 930 sm_trigger_run(); 931 return 0; 932 } 933 934 // CMAC calculation using AES Engineq 935 #ifdef USE_CMAC_ENGINE 936 937 static void sm_cmac_done_trampoline(void * arg){ 938 UNUSED(arg); 939 sm_cmac_active = 0; 940 (*sm_cmac_done_callback)(sm_cmac_hash); 941 sm_trigger_run(); 942 } 943 944 int sm_cmac_ready(void){ 945 return sm_cmac_active == 0u; 946 } 947 #endif 948 949 #ifdef ENABLE_LE_SECURE_CONNECTIONS 950 // generic cmac calculation 951 static void sm_cmac_message_start(const sm_key_t key, uint16_t message_len, const uint8_t * message, void (*done_callback)(uint8_t * hash)){ 952 sm_cmac_active = 1; 953 sm_cmac_done_callback = done_callback; 954 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 955 } 956 #endif 957 958 // cmac for ATT Message signing 959 #ifdef ENABLE_LE_SIGNED_WRITE 960 961 static void sm_cmac_generator_start(const sm_key_t key, uint16_t message_len, uint8_t (*get_byte_callback)(uint16_t offset), void (*done_callback)(uint8_t * hash)){ 962 sm_cmac_active = 1; 963 sm_cmac_done_callback = done_callback; 964 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 965 } 966 967 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 968 if (offset >= sm_cmac_signed_write_message_len) { 969 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 970 return 0; 971 } 972 973 offset = sm_cmac_signed_write_message_len - 1 - offset; 974 975 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 976 if (offset < 3){ 977 return sm_cmac_signed_write_header[offset]; 978 } 979 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 980 if (offset < actual_message_len_incl_header){ 981 return sm_cmac_signed_write_message[offset - 3]; 982 } 983 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 984 } 985 986 void sm_cmac_signed_write_start(const sm_key_t k, uint8_t opcode, hci_con_handle_t con_handle, uint16_t message_len, const uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t * hash)){ 987 // ATT Message Signing 988 sm_cmac_signed_write_header[0] = opcode; 989 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 990 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 991 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 992 sm_cmac_signed_write_message = message; 993 sm_cmac_signed_write_message_len = total_message_len; 994 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 995 } 996 #endif 997 998 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 999 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 1000 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 1001 switch (setup->sm_stk_generation_method){ 1002 case PK_RESP_INPUT: 1003 if (IS_RESPONDER(sm_conn->sm_role)){ 1004 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1005 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1006 } else { 1007 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)); 1008 } 1009 break; 1010 case PK_INIT_INPUT: 1011 if (IS_RESPONDER(sm_conn->sm_role)){ 1012 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)); 1013 } else { 1014 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1015 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1016 } 1017 break; 1018 case PK_BOTH_INPUT: 1019 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1020 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1021 break; 1022 case NUMERIC_COMPARISON: 1023 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1024 sm_notify_client_passkey(SM_EVENT_NUMERIC_COMPARISON_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 1025 break; 1026 case JUST_WORKS: 1027 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1028 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1029 break; 1030 case OOB: 1031 // client already provided OOB data, let's skip notification. 1032 break; 1033 default: 1034 btstack_assert(false); 1035 break; 1036 } 1037 } 1038 1039 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1040 int recv_flags; 1041 if (IS_RESPONDER(sm_conn->sm_role)){ 1042 // slave / responder 1043 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1044 } else { 1045 // master / initiator 1046 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1047 } 1048 1049 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1050 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1051 if (setup->sm_use_secure_connections){ 1052 recv_flags &= ~(SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION | SM_KEYDIST_FLAG_MASTER_IDENTIFICATION); 1053 } 1054 #endif 1055 1056 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1057 return (setup->sm_key_distribution_received_set & recv_flags) == recv_flags; 1058 } 1059 1060 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1061 if (sm_active_connection_handle == con_handle){ 1062 sm_timeout_stop(); 1063 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1064 log_info("sm: connection 0x%x released setup context", con_handle); 1065 1066 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1067 // generate new ec key after each pairing (that used it) 1068 if (setup->sm_use_secure_connections){ 1069 sm_ec_generate_new_key(); 1070 } 1071 #endif 1072 } 1073 } 1074 1075 static void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done 1076 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1077 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 1078 sm_done_for_handle(connection->sm_handle); 1079 } 1080 1081 static int sm_key_distribution_flags_for_auth_req(void){ 1082 1083 int flags = SM_KEYDIST_ID_KEY; 1084 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1085 // encryption and signing information only if bonding requested 1086 flags |= SM_KEYDIST_ENC_KEY; 1087 #ifdef ENABLE_LE_SIGNED_WRITE 1088 flags |= SM_KEYDIST_SIGN; 1089 #endif 1090 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1091 // LinkKey for CTKD requires SC 1092 if (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 1093 flags |= SM_KEYDIST_LINK_KEY; 1094 } 1095 #endif 1096 } 1097 return flags; 1098 } 1099 1100 static void sm_reset_setup(void){ 1101 // fill in sm setup 1102 setup->sm_state_vars = 0; 1103 setup->sm_keypress_notification = 0; 1104 sm_reset_tk(); 1105 } 1106 1107 static void sm_init_setup(sm_connection_t * sm_conn){ 1108 1109 // fill in sm setup 1110 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1111 (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1112 1113 // query client for Legacy Pairing OOB data 1114 setup->sm_have_oob_data = 0; 1115 if (sm_get_oob_data) { 1116 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1117 } 1118 1119 // if available and SC supported, also ask for SC OOB Data 1120 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1121 memset(setup->sm_ra, 0, 16); 1122 memset(setup->sm_rb, 0, 16); 1123 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1124 if (sm_get_sc_oob_data){ 1125 if (IS_RESPONDER(sm_conn->sm_role)){ 1126 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1127 sm_conn->sm_peer_addr_type, 1128 sm_conn->sm_peer_address, 1129 setup->sm_peer_confirm, 1130 setup->sm_ra); 1131 } else { 1132 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1133 sm_conn->sm_peer_addr_type, 1134 sm_conn->sm_peer_address, 1135 setup->sm_peer_confirm, 1136 setup->sm_rb); 1137 } 1138 } else { 1139 setup->sm_have_oob_data = 0; 1140 } 1141 } 1142 #endif 1143 1144 sm_pairing_packet_t * local_packet; 1145 if (IS_RESPONDER(sm_conn->sm_role)){ 1146 // slave 1147 local_packet = &setup->sm_s_pres; 1148 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1149 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1150 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1151 } else { 1152 // master 1153 local_packet = &setup->sm_m_preq; 1154 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1155 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1156 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1157 1158 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1159 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1160 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1161 } 1162 1163 uint8_t auth_req = sm_auth_req & ~SM_AUTHREQ_CT2; 1164 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1165 // set CT2 if SC + Bonding + CTKD 1166 const uint8_t auth_req_for_ct2 = SM_AUTHREQ_SECURE_CONNECTION | SM_AUTHREQ_BONDING; 1167 if ((auth_req & auth_req_for_ct2) == auth_req_for_ct2){ 1168 auth_req |= SM_AUTHREQ_CT2; 1169 } 1170 #endif 1171 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1172 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1173 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1174 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1175 } 1176 1177 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1178 1179 sm_pairing_packet_t * remote_packet; 1180 int remote_key_request; 1181 if (IS_RESPONDER(sm_conn->sm_role)){ 1182 // slave / responder 1183 remote_packet = &setup->sm_m_preq; 1184 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1185 } else { 1186 // master / initiator 1187 remote_packet = &setup->sm_s_pres; 1188 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1189 } 1190 1191 // check key size 1192 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1193 if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; 1194 1195 // decide on STK generation method / SC 1196 sm_setup_tk(); 1197 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1198 1199 // check if STK generation method is acceptable by client 1200 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1201 1202 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1203 // check LE SC Only mode 1204 if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ 1205 log_info("SC Only mode active but SC not possible"); 1206 return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1207 } 1208 1209 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1210 if (setup->sm_use_secure_connections){ 1211 remote_key_request &= ~SM_KEYDIST_ENC_KEY; 1212 } 1213 #endif 1214 1215 // identical to responder 1216 sm_setup_key_distribution(remote_key_request); 1217 1218 // JUST WORKS doens't provide authentication 1219 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1220 1221 return 0; 1222 } 1223 1224 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1225 1226 // cache and reset context 1227 int matched_device_id = sm_address_resolution_test; 1228 address_resolution_mode_t mode = sm_address_resolution_mode; 1229 void * context = sm_address_resolution_context; 1230 1231 // reset context 1232 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1233 sm_address_resolution_context = NULL; 1234 sm_address_resolution_test = -1; 1235 hci_con_handle_t con_handle = 0; 1236 1237 sm_connection_t * sm_connection; 1238 sm_key_t ltk; 1239 int have_ltk; 1240 #ifdef ENABLE_LE_CENTRAL 1241 int trigger_pairing; 1242 #endif 1243 switch (mode){ 1244 case ADDRESS_RESOLUTION_GENERAL: 1245 break; 1246 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1247 sm_connection = (sm_connection_t *) context; 1248 con_handle = sm_connection->sm_handle; 1249 1250 // have ltk -> start encryption / send security request 1251 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1252 // "When a bond has been created between two devices, any reconnection should result in the local device 1253 // enabling or requesting encryption with the remote device before initiating any service request." 1254 1255 switch (event){ 1256 case ADDRESS_RESOLUTION_SUCCEEDED: 1257 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1258 sm_connection->sm_le_db_index = matched_device_id; 1259 log_info("ADDRESS_RESOLUTION_SUCCEEDED, index %d", sm_connection->sm_le_db_index); 1260 1261 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1262 have_ltk = !sm_is_null_key(ltk); 1263 1264 if (sm_connection->sm_role) { 1265 1266 #ifdef ENABLE_LE_PERIPHERAL 1267 1268 // LTK request received before, IRK required -> start LTK calculation 1269 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1270 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1271 break; 1272 } 1273 1274 if (have_ltk) { 1275 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1276 log_info("central: enable encryption for bonded device"); 1277 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1278 sm_reencryption_started(sm_connection); 1279 sm_trigger_run(); 1280 #else 1281 log_info("central: defer security request for bonded device"); 1282 #endif 1283 } 1284 #endif 1285 } else { 1286 1287 #ifdef ENABLE_LE_CENTRAL 1288 1289 // check if pairing already requested and reset requests 1290 trigger_pairing = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1291 log_info("central: pairing request local %u, remote %u => trigger_pairing %u. have_ltk %u", 1292 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, trigger_pairing, have_ltk); 1293 sm_connection->sm_security_request_received = 0; 1294 sm_connection->sm_pairing_requested = 0; 1295 bool trigger_reencryption = false; 1296 1297 if (have_ltk){ 1298 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1299 trgigger_reencryptipm = true; 1300 #else 1301 if (trigger_pairing){ 1302 trigger_reencryption = true; 1303 } else { 1304 log_info("central: defer enabling encryption for bonded device"); 1305 } 1306 #endif 1307 } 1308 1309 if (trigger_reencryption){ 1310 log_info("central: enable encryption for bonded device"); 1311 sm_connection->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 1312 sm_reencryption_started(sm_connection); 1313 break; 1314 } 1315 1316 // pairing_request -> send pairing request 1317 if (trigger_pairing){ 1318 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1319 break; 1320 } 1321 } 1322 #endif 1323 break; 1324 case ADDRESS_RESOLUTION_FAILED: 1325 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1326 if (sm_connection->sm_role) { 1327 // LTK request received before, IRK required -> negative LTK reply 1328 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1329 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1330 } 1331 break; 1332 } 1333 #ifdef ENABLE_LE_CENTRAL 1334 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1335 sm_connection->sm_security_request_received = 0; 1336 sm_connection->sm_pairing_requested = 0; 1337 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1338 #endif 1339 break; 1340 1341 default: 1342 btstack_assert(false); 1343 break; 1344 } 1345 break; 1346 default: 1347 break; 1348 } 1349 1350 switch (event){ 1351 case ADDRESS_RESOLUTION_SUCCEEDED: 1352 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1353 break; 1354 case ADDRESS_RESOLUTION_FAILED: 1355 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1356 break; 1357 default: 1358 btstack_assert(false); 1359 break; 1360 } 1361 } 1362 1363 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1364 1365 int le_db_index = -1; 1366 1367 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1368 int bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1369 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1370 & SM_AUTHREQ_BONDING ) != 0u; 1371 1372 if (bonding_enabed){ 1373 1374 // lookup device based on IRK 1375 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1376 int i; 1377 for (i=0; i < le_device_db_max_count(); i++){ 1378 sm_key_t irk; 1379 bd_addr_t address; 1380 int address_type = BD_ADDR_TYPE_UNKNOWN; 1381 le_device_db_info(i, &address_type, address, irk); 1382 // skip unused entries 1383 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1384 // compare IRK 1385 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1386 1387 log_info("sm: device found for IRK, updating"); 1388 le_db_index = i; 1389 break; 1390 } 1391 } else { 1392 // assert IRK is set to zero 1393 memset(setup->sm_peer_irk, 0, 16); 1394 } 1395 1396 // if not found, lookup via public address if possible 1397 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1398 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1399 int i; 1400 for (i=0; i < le_device_db_max_count(); i++){ 1401 bd_addr_t address; 1402 int address_type = BD_ADDR_TYPE_UNKNOWN; 1403 le_device_db_info(i, &address_type, address, NULL); 1404 // skip unused entries 1405 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1406 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1407 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1408 log_info("sm: device found for public address, updating"); 1409 le_db_index = i; 1410 break; 1411 } 1412 } 1413 } 1414 1415 // if not found, add to db 1416 bool new_to_le_device_db = false; 1417 if (le_db_index < 0) { 1418 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1419 new_to_le_device_db = true; 1420 } 1421 1422 if (le_db_index >= 0){ 1423 1424 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1425 if (!new_to_le_device_db){ 1426 hci_remove_le_device_db_entry_from_resolving_list(le_db_index); 1427 } 1428 hci_load_le_device_db_entry_into_resolving_list(le_db_index); 1429 #else 1430 UNUSED(new_to_le_device_db); 1431 #endif 1432 1433 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1434 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1435 1436 #ifdef ENABLE_LE_SIGNED_WRITE 1437 // store local CSRK 1438 setup->sm_le_device_index = le_db_index; 1439 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1440 log_info("sm: store local CSRK"); 1441 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1442 le_device_db_local_counter_set(le_db_index, 0); 1443 } 1444 1445 // store remote CSRK 1446 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1447 log_info("sm: store remote CSRK"); 1448 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1449 le_device_db_remote_counter_set(le_db_index, 0); 1450 } 1451 #endif 1452 // store encryption information for secure connections: LTK generated by ECDH 1453 if (setup->sm_use_secure_connections){ 1454 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1455 uint8_t zero_rand[8]; 1456 memset(zero_rand, 0, 8); 1457 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1458 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1459 } 1460 1461 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1462 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1463 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1464 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1465 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1466 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1467 1468 } 1469 } 1470 } else { 1471 log_info("Ignoring received keys, bonding not enabled"); 1472 } 1473 1474 // keep le_db_index 1475 sm_conn->sm_le_db_index = le_db_index; 1476 } 1477 1478 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1479 setup->sm_pairing_failed_reason = reason; 1480 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1481 } 1482 1483 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1484 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1485 } 1486 1487 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1488 1489 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1490 static int sm_passkey_used(stk_generation_method_t method); 1491 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1492 1493 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1494 if (setup->sm_stk_generation_method == OOB){ 1495 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1496 } else { 1497 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_next_w2_cmac_for_confirmation, (void *)(uintptr_t) sm_conn->sm_handle); 1498 } 1499 } 1500 1501 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1502 if (IS_RESPONDER(sm_conn->sm_role)){ 1503 // Responder 1504 if (setup->sm_stk_generation_method == OOB){ 1505 // generate Nb 1506 log_info("Generate Nb"); 1507 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_next_send_pairing_random, (void *)(uintptr_t) sm_conn->sm_handle); 1508 } else { 1509 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1510 } 1511 } else { 1512 // Initiator role 1513 switch (setup->sm_stk_generation_method){ 1514 case JUST_WORKS: 1515 sm_sc_prepare_dhkey_check(sm_conn); 1516 break; 1517 1518 case NUMERIC_COMPARISON: 1519 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1520 break; 1521 case PK_INIT_INPUT: 1522 case PK_RESP_INPUT: 1523 case PK_BOTH_INPUT: 1524 if (setup->sm_passkey_bit < 20u) { 1525 sm_sc_start_calculating_local_confirm(sm_conn); 1526 } else { 1527 sm_sc_prepare_dhkey_check(sm_conn); 1528 } 1529 break; 1530 case OOB: 1531 sm_sc_prepare_dhkey_check(sm_conn); 1532 break; 1533 default: 1534 btstack_assert(false); 1535 break; 1536 } 1537 } 1538 } 1539 1540 static void sm_sc_cmac_done(uint8_t * hash){ 1541 log_info("sm_sc_cmac_done: "); 1542 log_info_hexdump(hash, 16); 1543 1544 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1545 sm_sc_oob_state = SM_SC_OOB_IDLE; 1546 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1547 return; 1548 } 1549 1550 sm_connection_t * sm_conn = sm_cmac_connection; 1551 sm_cmac_connection = NULL; 1552 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1553 link_key_type_t link_key_type; 1554 #endif 1555 1556 switch (sm_conn->sm_engine_state){ 1557 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1558 (void)memcpy(setup->sm_local_confirm, hash, 16); 1559 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1560 break; 1561 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1562 // check 1563 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1564 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1565 break; 1566 } 1567 sm_sc_state_after_receiving_random(sm_conn); 1568 break; 1569 case SM_SC_W4_CALCULATE_G2: { 1570 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1571 big_endian_store_32(setup->sm_tk, 12, vab); 1572 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1573 sm_trigger_user_response(sm_conn); 1574 break; 1575 } 1576 case SM_SC_W4_CALCULATE_F5_SALT: 1577 (void)memcpy(setup->sm_t, hash, 16); 1578 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1579 break; 1580 case SM_SC_W4_CALCULATE_F5_MACKEY: 1581 (void)memcpy(setup->sm_mackey, hash, 16); 1582 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1583 break; 1584 case SM_SC_W4_CALCULATE_F5_LTK: 1585 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1586 // Errata Service Release to the Bluetooth Specification: ESR09 1587 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1588 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1589 (void)memcpy(setup->sm_ltk, hash, 16); 1590 (void)memcpy(setup->sm_local_ltk, hash, 16); 1591 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1592 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1593 break; 1594 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1595 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1596 if (IS_RESPONDER(sm_conn->sm_role)){ 1597 // responder 1598 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1599 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1600 } else { 1601 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1602 } 1603 } else { 1604 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1605 } 1606 break; 1607 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1608 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1609 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1610 break; 1611 } 1612 if (IS_RESPONDER(sm_conn->sm_role)){ 1613 // responder 1614 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1615 } else { 1616 // initiator 1617 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1618 } 1619 break; 1620 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1621 case SM_SC_W4_CALCULATE_ILK: 1622 (void)memcpy(setup->sm_t, hash, 16); 1623 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY; 1624 break; 1625 case SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY: 1626 reverse_128(hash, setup->sm_t); 1627 link_key_type = sm_conn->sm_connection_authenticated ? 1628 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1629 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1630 gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); 1631 if (IS_RESPONDER(sm_conn->sm_role)){ 1632 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1633 } else { 1634 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1635 } 1636 sm_pairing_complete(sm_conn, ERROR_CODE_SUCCESS, 0); 1637 sm_done_for_handle(sm_conn->sm_handle); 1638 break; 1639 #endif 1640 default: 1641 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1642 break; 1643 } 1644 sm_trigger_run(); 1645 } 1646 1647 static void f4_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, uint8_t z){ 1648 const uint16_t message_len = 65; 1649 sm_cmac_connection = sm_conn; 1650 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1651 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1652 sm_cmac_sc_buffer[64] = z; 1653 log_info("f4 key"); 1654 log_info_hexdump(x, 16); 1655 log_info("f4 message"); 1656 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1657 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1658 } 1659 1660 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1661 static const uint8_t f5_length[] = { 0x01, 0x00}; 1662 1663 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1664 1665 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1666 1667 log_info("f5_calculate_salt"); 1668 // calculate salt for f5 1669 const uint16_t message_len = 32; 1670 sm_cmac_connection = sm_conn; 1671 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1672 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1673 } 1674 1675 static inline void f5_mackkey(sm_connection_t * sm_conn, sm_key_t t, const sm_key_t n1, const sm_key_t n2, const sm_key56_t a1, const sm_key56_t a2){ 1676 const uint16_t message_len = 53; 1677 sm_cmac_connection = sm_conn; 1678 1679 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1680 sm_cmac_sc_buffer[0] = 0; 1681 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1682 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1683 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1684 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1685 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1686 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1687 log_info("f5 key"); 1688 log_info_hexdump(t, 16); 1689 log_info("f5 message for MacKey"); 1690 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1691 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1692 } 1693 1694 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1695 sm_key56_t bd_addr_master, bd_addr_slave; 1696 bd_addr_master[0] = setup->sm_m_addr_type; 1697 bd_addr_slave[0] = setup->sm_s_addr_type; 1698 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1699 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1700 if (IS_RESPONDER(sm_conn->sm_role)){ 1701 // responder 1702 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1703 } else { 1704 // initiator 1705 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1706 } 1707 } 1708 1709 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1710 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1711 const uint16_t message_len = 53; 1712 sm_cmac_connection = sm_conn; 1713 sm_cmac_sc_buffer[0] = 1; 1714 // 1..52 setup before 1715 log_info("f5 key"); 1716 log_info_hexdump(t, 16); 1717 log_info("f5 message for LTK"); 1718 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1719 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1720 } 1721 1722 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1723 f5_ltk(sm_conn, setup->sm_t); 1724 } 1725 1726 static void f6_setup(const sm_key_t n1, const sm_key_t n2, const sm_key_t r, const sm_key24_t io_cap, const sm_key56_t a1, const sm_key56_t a2){ 1727 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1728 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1729 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1730 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1731 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1732 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1733 } 1734 1735 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ 1736 const uint16_t message_len = 65; 1737 sm_cmac_connection = sm_conn; 1738 log_info("f6 key"); 1739 log_info_hexdump(w, 16); 1740 log_info("f6 message"); 1741 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1742 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1743 } 1744 1745 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1746 // - U is 256 bits 1747 // - V is 256 bits 1748 // - X is 128 bits 1749 // - Y is 128 bits 1750 static void g2_engine(sm_connection_t * sm_conn, const sm_key256_t u, const sm_key256_t v, const sm_key_t x, const sm_key_t y){ 1751 const uint16_t message_len = 80; 1752 sm_cmac_connection = sm_conn; 1753 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1754 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1755 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1756 log_info("g2 key"); 1757 log_info_hexdump(x, 16); 1758 log_info("g2 message"); 1759 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1760 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1761 } 1762 1763 static void g2_calculate(sm_connection_t * sm_conn) { 1764 // calc Va if numeric comparison 1765 if (IS_RESPONDER(sm_conn->sm_role)){ 1766 // responder 1767 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1768 } else { 1769 // initiator 1770 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1771 } 1772 } 1773 1774 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1775 uint8_t z = 0; 1776 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1777 // some form of passkey 1778 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1779 z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); 1780 setup->sm_passkey_bit++; 1781 } 1782 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1783 } 1784 1785 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1786 // OOB 1787 if (setup->sm_stk_generation_method == OOB){ 1788 if (IS_RESPONDER(sm_conn->sm_role)){ 1789 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1790 } else { 1791 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1792 } 1793 return; 1794 } 1795 1796 uint8_t z = 0; 1797 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1798 // some form of passkey 1799 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1800 // sm_passkey_bit was increased before sending confirm value 1801 z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); 1802 } 1803 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1804 } 1805 1806 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1807 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) ? 1 : 0); 1808 1809 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1810 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1811 return; 1812 } else { 1813 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1814 } 1815 } 1816 1817 static void sm_sc_dhkey_calculated(void * arg){ 1818 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1819 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1820 if (sm_conn == NULL) return; 1821 1822 log_info("dhkey"); 1823 log_info_hexdump(&setup->sm_dhkey[0], 32); 1824 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1825 // trigger next step 1826 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1827 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1828 } 1829 sm_trigger_run(); 1830 } 1831 1832 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1833 // calculate DHKCheck 1834 sm_key56_t bd_addr_master, bd_addr_slave; 1835 bd_addr_master[0] = setup->sm_m_addr_type; 1836 bd_addr_slave[0] = setup->sm_s_addr_type; 1837 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1838 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1839 uint8_t iocap_a[3]; 1840 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1841 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1842 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1843 uint8_t iocap_b[3]; 1844 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1845 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1846 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1847 if (IS_RESPONDER(sm_conn->sm_role)){ 1848 // responder 1849 f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1850 f6_engine(sm_conn, setup->sm_mackey); 1851 } else { 1852 // initiator 1853 f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1854 f6_engine(sm_conn, setup->sm_mackey); 1855 } 1856 } 1857 1858 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1859 // validate E = f6() 1860 sm_key56_t bd_addr_master, bd_addr_slave; 1861 bd_addr_master[0] = setup->sm_m_addr_type; 1862 bd_addr_slave[0] = setup->sm_s_addr_type; 1863 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1864 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1865 1866 uint8_t iocap_a[3]; 1867 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1868 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1869 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1870 uint8_t iocap_b[3]; 1871 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1872 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1873 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1874 if (IS_RESPONDER(sm_conn->sm_role)){ 1875 // responder 1876 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1877 f6_engine(sm_conn, setup->sm_mackey); 1878 } else { 1879 // initiator 1880 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1881 f6_engine(sm_conn, setup->sm_mackey); 1882 } 1883 } 1884 1885 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1886 1887 // 1888 // Link Key Conversion Function h6 1889 // 1890 // h6(W, keyID) = AES-CMAC_W(keyID) 1891 // - W is 128 bits 1892 // - keyID is 32 bits 1893 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1894 const uint16_t message_len = 4; 1895 sm_cmac_connection = sm_conn; 1896 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1897 log_info("h6 key"); 1898 log_info_hexdump(w, 16); 1899 log_info("h6 message"); 1900 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1901 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1902 } 1903 // 1904 // Link Key Conversion Function h7 1905 // 1906 // h7(SALT, W) = AES-CMAC_SALT(W) 1907 // - SALT is 128 bits 1908 // - W is 128 bits 1909 static void h7_engine(sm_connection_t * sm_conn, const sm_key_t salt, const sm_key_t w) { 1910 const uint16_t message_len = 16; 1911 sm_cmac_connection = sm_conn; 1912 log_info("h7 key"); 1913 log_info_hexdump(salt, 16); 1914 log_info("h7 message"); 1915 log_info_hexdump(w, 16); 1916 sm_cmac_message_start(salt, message_len, w, &sm_sc_cmac_done); 1917 } 1918 1919 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1920 // Errata Service Release to the Bluetooth Specification: ESR09 1921 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1922 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1923 1924 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1925 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1926 } 1927 1928 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1929 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1930 } 1931 1932 static void h7_calculate_ilk(sm_connection_t * sm_conn){ 1933 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x31}; // "tmp1" 1934 h7_engine(sm_conn, salt, setup->sm_local_ltk); 1935 } 1936 #endif 1937 1938 #endif 1939 1940 // key management legacy connections: 1941 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1942 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1943 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1944 // - responder reconnects: responder uses LTK receveived from master 1945 1946 // key management secure connections: 1947 // - both devices store same LTK from ECDH key exchange. 1948 1949 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1950 static void sm_load_security_info(sm_connection_t * sm_connection){ 1951 int encryption_key_size; 1952 int authenticated; 1953 int authorized; 1954 int secure_connection; 1955 1956 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1957 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1958 &encryption_key_size, &authenticated, &authorized, &secure_connection); 1959 log_info("db index %u, key size %u, authenticated %u, authorized %u, secure connetion %u", sm_connection->sm_le_db_index, encryption_key_size, authenticated, authorized, secure_connection); 1960 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1961 sm_connection->sm_connection_authenticated = authenticated; 1962 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1963 sm_connection->sm_connection_sc = secure_connection; 1964 } 1965 #endif 1966 1967 #ifdef ENABLE_LE_PERIPHERAL 1968 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1969 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1970 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1971 // re-establish used key encryption size 1972 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1973 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; 1974 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1975 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; 1976 // Legacy paring -> not SC 1977 sm_connection->sm_connection_sc = 0; 1978 log_info("sm: received ltk request with key size %u, authenticated %u", 1979 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1980 } 1981 #endif 1982 1983 // distributed key generation 1984 static bool sm_run_dpkg(void){ 1985 switch (dkg_state){ 1986 case DKG_CALC_IRK: 1987 // already busy? 1988 if (sm_aes128_state == SM_AES128_IDLE) { 1989 log_info("DKG_CALC_IRK started"); 1990 // IRK = d1(IR, 1, 0) 1991 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 1992 sm_aes128_state = SM_AES128_ACTIVE; 1993 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 1994 return true; 1995 } 1996 break; 1997 case DKG_CALC_DHK: 1998 // already busy? 1999 if (sm_aes128_state == SM_AES128_IDLE) { 2000 log_info("DKG_CALC_DHK started"); 2001 // DHK = d1(IR, 3, 0) 2002 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 2003 sm_aes128_state = SM_AES128_ACTIVE; 2004 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 2005 return true; 2006 } 2007 break; 2008 default: 2009 break; 2010 } 2011 return false; 2012 } 2013 2014 // random address updates 2015 static bool sm_run_rau(void){ 2016 switch (rau_state){ 2017 case RAU_GET_RANDOM: 2018 rau_state = RAU_W4_RANDOM; 2019 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 2020 return true; 2021 case RAU_GET_ENC: 2022 // already busy? 2023 if (sm_aes128_state == SM_AES128_IDLE) { 2024 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 2025 sm_aes128_state = SM_AES128_ACTIVE; 2026 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 2027 return true; 2028 } 2029 break; 2030 case RAU_SET_ADDRESS: 2031 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 2032 rau_state = RAU_IDLE; 2033 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 2034 return true; 2035 default: 2036 break; 2037 } 2038 return false; 2039 } 2040 2041 // CSRK Lookup 2042 static bool sm_run_csrk(void){ 2043 btstack_linked_list_iterator_t it; 2044 2045 // -- if csrk lookup ready, find connection that require csrk lookup 2046 if (sm_address_resolution_idle()){ 2047 hci_connections_get_iterator(&it); 2048 while(btstack_linked_list_iterator_has_next(&it)){ 2049 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2050 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2051 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2052 // and start lookup 2053 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); 2054 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2055 break; 2056 } 2057 } 2058 } 2059 2060 // -- if csrk lookup ready, resolved addresses for received addresses 2061 if (sm_address_resolution_idle()) { 2062 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2063 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2064 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2065 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2066 btstack_memory_sm_lookup_entry_free(entry); 2067 } 2068 } 2069 2070 // -- Continue with CSRK device lookup by public or resolvable private address 2071 if (!sm_address_resolution_idle()){ 2072 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 2073 while (sm_address_resolution_test < le_device_db_max_count()){ 2074 int addr_type = BD_ADDR_TYPE_UNKNOWN; 2075 bd_addr_t addr; 2076 sm_key_t irk; 2077 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2078 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 2079 2080 // skip unused entries 2081 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 2082 sm_address_resolution_test++; 2083 continue; 2084 } 2085 2086 if ((sm_address_resolution_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 2087 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 2088 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 2089 break; 2090 } 2091 2092 // if connection type is public, it must be a different one 2093 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 2094 sm_address_resolution_test++; 2095 continue; 2096 } 2097 2098 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2099 2100 log_info("LE Device Lookup: calculate AH"); 2101 log_info_key("IRK", irk); 2102 2103 (void)memcpy(sm_aes128_key, irk, 16); 2104 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 2105 sm_address_resolution_ah_calculation_active = 1; 2106 sm_aes128_state = SM_AES128_ACTIVE; 2107 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 2108 return true; 2109 } 2110 2111 if (sm_address_resolution_test >= le_device_db_max_count()){ 2112 log_info("LE Device Lookup: not found"); 2113 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2114 } 2115 } 2116 return false; 2117 } 2118 2119 // SC OOB 2120 static bool sm_run_oob(void){ 2121 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2122 switch (sm_sc_oob_state){ 2123 case SM_SC_OOB_W2_CALC_CONFIRM: 2124 if (!sm_cmac_ready()) break; 2125 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2126 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2127 return true; 2128 default: 2129 break; 2130 } 2131 #endif 2132 return false; 2133 } 2134 2135 // handle basic actions that don't requires the full context 2136 static bool sm_run_basic(void){ 2137 btstack_linked_list_iterator_t it; 2138 hci_connections_get_iterator(&it); 2139 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2140 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2141 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2142 switch(sm_connection->sm_engine_state){ 2143 // responder side 2144 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2145 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2146 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2147 return true; 2148 2149 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2150 case SM_SC_RECEIVED_LTK_REQUEST: 2151 switch (sm_connection->sm_irk_lookup_state){ 2152 case IRK_LOOKUP_FAILED: 2153 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 2154 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2155 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2156 return true; 2157 default: 2158 break; 2159 } 2160 break; 2161 #endif 2162 default: 2163 break; 2164 } 2165 } 2166 return false; 2167 } 2168 2169 static void sm_run_activate_connection(void){ 2170 // Find connections that requires setup context and make active if no other is locked 2171 btstack_linked_list_iterator_t it; 2172 hci_connections_get_iterator(&it); 2173 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2174 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2175 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2176 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2177 int done = 1; 2178 int err; 2179 UNUSED(err); 2180 2181 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2182 // assert ec key is ready 2183 if ( (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2184 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST) 2185 || (sm_connection->sm_engine_state == SM_RESPONDER_SEND_SECURITY_REQUEST)){ 2186 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2187 sm_ec_generate_new_key(); 2188 } 2189 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2190 continue; 2191 } 2192 } 2193 #endif 2194 2195 switch (sm_connection->sm_engine_state) { 2196 #ifdef ENABLE_LE_PERIPHERAL 2197 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2198 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2199 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2200 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2201 case SM_SC_RECEIVED_LTK_REQUEST: 2202 #endif 2203 #endif 2204 #ifdef ENABLE_LE_CENTRAL 2205 case SM_INITIATOR_PH4_HAS_LTK: 2206 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2207 #endif 2208 // just lock context 2209 break; 2210 default: 2211 done = 0; 2212 break; 2213 } 2214 if (done){ 2215 sm_active_connection_handle = sm_connection->sm_handle; 2216 log_info("sm: connection 0x%04x locked setup context as %s, state %u", sm_active_connection_handle, sm_connection->sm_role ? "responder" : "initiator", sm_connection->sm_engine_state); 2217 } 2218 } 2219 } 2220 2221 static void sm_run(void){ 2222 2223 // assert that stack has already bootet 2224 if (hci_get_state() != HCI_STATE_WORKING) return; 2225 2226 // assert that we can send at least commands 2227 if (!hci_can_send_command_packet_now()) return; 2228 2229 // pause until IR/ER are ready 2230 if (sm_persistent_keys_random_active) return; 2231 2232 bool done; 2233 2234 // 2235 // non-connection related behaviour 2236 // 2237 2238 done = sm_run_dpkg(); 2239 if (done) return; 2240 2241 done = sm_run_rau(); 2242 if (done) return; 2243 2244 done = sm_run_csrk(); 2245 if (done) return; 2246 2247 done = sm_run_oob(); 2248 if (done) return; 2249 2250 // assert that we can send at least commands - cmd might have been sent by crypto engine 2251 if (!hci_can_send_command_packet_now()) return; 2252 2253 // handle basic actions that don't requires the full context 2254 done = sm_run_basic(); 2255 if (done) return; 2256 2257 // 2258 // active connection handling 2259 // -- use loop to handle next connection if lock on setup context is released 2260 2261 while (true) { 2262 2263 sm_run_activate_connection(); 2264 2265 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2266 2267 // 2268 // active connection handling 2269 // 2270 2271 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2272 if (!connection) { 2273 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2274 return; 2275 } 2276 2277 // assert that we could send a SM PDU - not needed for all of the following 2278 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2279 log_info("cannot send now, requesting can send now event"); 2280 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2281 return; 2282 } 2283 2284 // send keypress notifications 2285 if (setup->sm_keypress_notification){ 2286 int i; 2287 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2288 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2289 uint8_t action = 0; 2290 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2291 if (flags & (1u<<i)){ 2292 int clear_flag = 1; 2293 switch (i){ 2294 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2295 case SM_KEYPRESS_PASSKEY_CLEARED: 2296 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2297 default: 2298 break; 2299 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2300 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2301 num_actions--; 2302 clear_flag = num_actions == 0u; 2303 break; 2304 } 2305 if (clear_flag){ 2306 flags &= ~(1<<i); 2307 } 2308 action = i; 2309 break; 2310 } 2311 } 2312 setup->sm_keypress_notification = (num_actions << 5) | flags; 2313 2314 // send keypress notification 2315 uint8_t buffer[2]; 2316 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2317 buffer[1] = action; 2318 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2319 2320 // try 2321 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2322 return; 2323 } 2324 2325 int key_distribution_flags; 2326 UNUSED(key_distribution_flags); 2327 int err; 2328 UNUSED(err); 2329 2330 log_info("sm_run: state %u", connection->sm_engine_state); 2331 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2332 log_info("sm_run // cannot send"); 2333 } 2334 switch (connection->sm_engine_state){ 2335 2336 // general 2337 case SM_GENERAL_SEND_PAIRING_FAILED: { 2338 uint8_t buffer[2]; 2339 buffer[0] = SM_CODE_PAIRING_FAILED; 2340 buffer[1] = setup->sm_pairing_failed_reason; 2341 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2342 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2343 sm_pairing_complete(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2344 sm_done_for_handle(connection->sm_handle); 2345 break; 2346 } 2347 2348 // secure connections, initiator + responding states 2349 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2350 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2351 if (!sm_cmac_ready()) break; 2352 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2353 sm_sc_calculate_local_confirm(connection); 2354 break; 2355 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2356 if (!sm_cmac_ready()) break; 2357 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2358 sm_sc_calculate_remote_confirm(connection); 2359 break; 2360 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2361 if (!sm_cmac_ready()) break; 2362 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2363 sm_sc_calculate_f6_for_dhkey_check(connection); 2364 break; 2365 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2366 if (!sm_cmac_ready()) break; 2367 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2368 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2369 break; 2370 case SM_SC_W2_CALCULATE_F5_SALT: 2371 if (!sm_cmac_ready()) break; 2372 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2373 f5_calculate_salt(connection); 2374 break; 2375 case SM_SC_W2_CALCULATE_F5_MACKEY: 2376 if (!sm_cmac_ready()) break; 2377 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2378 f5_calculate_mackey(connection); 2379 break; 2380 case SM_SC_W2_CALCULATE_F5_LTK: 2381 if (!sm_cmac_ready()) break; 2382 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2383 f5_calculate_ltk(connection); 2384 break; 2385 case SM_SC_W2_CALCULATE_G2: 2386 if (!sm_cmac_ready()) break; 2387 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2388 g2_calculate(connection); 2389 break; 2390 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2391 case SM_SC_W2_CALCULATE_ILK_USING_H6: 2392 if (!sm_cmac_ready()) break; 2393 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 2394 h6_calculate_ilk(connection); 2395 break; 2396 case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: 2397 if (!sm_cmac_ready()) break; 2398 connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; 2399 h6_calculate_br_edr_link_key(connection); 2400 break; 2401 case SM_SC_W2_CALCULATE_ILK_USING_H7: 2402 if (!sm_cmac_ready()) break; 2403 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 2404 h7_calculate_ilk(connection); 2405 break; 2406 #endif 2407 #endif 2408 2409 #ifdef ENABLE_LE_CENTRAL 2410 // initiator side 2411 2412 case SM_INITIATOR_PH4_HAS_LTK: { 2413 sm_reset_setup(); 2414 sm_load_security_info(connection); 2415 2416 sm_key_t peer_ltk_flipped; 2417 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2418 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 2419 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2420 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2421 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2422 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2423 return; 2424 } 2425 2426 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2427 sm_reset_setup(); 2428 sm_init_setup(connection); 2429 sm_timeout_start(connection); 2430 2431 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2432 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2433 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2434 sm_timeout_reset(connection); 2435 break; 2436 #endif 2437 2438 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2439 2440 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2441 int trigger_user_response = 0; 2442 int trigger_start_calculating_local_confirm = 0; 2443 uint8_t buffer[65]; 2444 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2445 // 2446 reverse_256(&ec_q[0], &buffer[1]); 2447 reverse_256(&ec_q[32], &buffer[33]); 2448 2449 #ifdef ENABLE_TESTING_SUPPORT 2450 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2451 log_info("testing_support: invalidating public key"); 2452 // flip single bit of public key coordinate 2453 buffer[1] ^= 1; 2454 } 2455 #endif 2456 2457 // stk generation method 2458 // passkey entry: notify app to show passkey or to request passkey 2459 switch (setup->sm_stk_generation_method){ 2460 case JUST_WORKS: 2461 case NUMERIC_COMPARISON: 2462 if (IS_RESPONDER(connection->sm_role)){ 2463 // responder 2464 trigger_start_calculating_local_confirm = 1; 2465 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2466 } else { 2467 // initiator 2468 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2469 } 2470 break; 2471 case PK_INIT_INPUT: 2472 case PK_RESP_INPUT: 2473 case PK_BOTH_INPUT: 2474 // use random TK for display 2475 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2476 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2477 setup->sm_passkey_bit = 0; 2478 2479 if (IS_RESPONDER(connection->sm_role)){ 2480 // responder 2481 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2482 } else { 2483 // initiator 2484 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2485 } 2486 trigger_user_response = 1; 2487 break; 2488 case OOB: 2489 if (IS_RESPONDER(connection->sm_role)){ 2490 // responder 2491 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2492 } else { 2493 // initiator 2494 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2495 } 2496 break; 2497 default: 2498 btstack_assert(false); 2499 break; 2500 } 2501 2502 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2503 sm_timeout_reset(connection); 2504 2505 // trigger user response and calc confirm after sending pdu 2506 if (trigger_user_response){ 2507 sm_trigger_user_response(connection); 2508 } 2509 if (trigger_start_calculating_local_confirm){ 2510 sm_sc_start_calculating_local_confirm(connection); 2511 } 2512 break; 2513 } 2514 case SM_SC_SEND_CONFIRMATION: { 2515 uint8_t buffer[17]; 2516 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2517 reverse_128(setup->sm_local_confirm, &buffer[1]); 2518 if (IS_RESPONDER(connection->sm_role)){ 2519 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2520 } else { 2521 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2522 } 2523 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2524 sm_timeout_reset(connection); 2525 break; 2526 } 2527 case SM_SC_SEND_PAIRING_RANDOM: { 2528 uint8_t buffer[17]; 2529 buffer[0] = SM_CODE_PAIRING_RANDOM; 2530 reverse_128(setup->sm_local_nonce, &buffer[1]); 2531 log_info("stk method %u, num bits %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2532 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2533 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2534 if (IS_RESPONDER(connection->sm_role)){ 2535 // responder 2536 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2537 } else { 2538 // initiator 2539 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2540 } 2541 } else { 2542 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2543 if (IS_RESPONDER(connection->sm_role)){ 2544 // responder 2545 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2546 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2547 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2548 } else { 2549 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2550 sm_sc_prepare_dhkey_check(connection); 2551 } 2552 } else { 2553 // initiator 2554 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2555 } 2556 } 2557 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2558 sm_timeout_reset(connection); 2559 break; 2560 } 2561 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2562 uint8_t buffer[17]; 2563 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2564 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2565 2566 if (IS_RESPONDER(connection->sm_role)){ 2567 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2568 } else { 2569 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2570 } 2571 2572 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2573 sm_timeout_reset(connection); 2574 break; 2575 } 2576 2577 #endif 2578 2579 #ifdef ENABLE_LE_PERIPHERAL 2580 2581 case SM_RESPONDER_SEND_SECURITY_REQUEST: { 2582 const uint8_t buffer[2] = {SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2583 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2584 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t *) buffer, sizeof(buffer)); 2585 sm_timeout_start(connection); 2586 break; 2587 } 2588 2589 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2590 case SM_SC_RECEIVED_LTK_REQUEST: 2591 switch (connection->sm_irk_lookup_state){ 2592 case IRK_LOOKUP_SUCCEEDED: 2593 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2594 // start using context by loading security info 2595 sm_reset_setup(); 2596 sm_load_security_info(connection); 2597 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2598 (void)memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2599 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2600 sm_reencryption_started(connection); 2601 sm_trigger_run(); 2602 break; 2603 } 2604 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2605 connection->sm_engine_state = SM_RESPONDER_IDLE; 2606 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2607 return; 2608 default: 2609 // just wait until IRK lookup is completed 2610 break; 2611 } 2612 break; 2613 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2614 2615 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2616 sm_reset_setup(); 2617 sm_init_setup(connection); 2618 // recover pairing request 2619 (void)memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2620 err = sm_stk_generation_init(connection); 2621 2622 #ifdef ENABLE_TESTING_SUPPORT 2623 if ((0 < test_pairing_failure) && (test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED)){ 2624 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2625 err = test_pairing_failure; 2626 } 2627 #endif 2628 if (err){ 2629 setup->sm_pairing_failed_reason = err; 2630 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2631 sm_trigger_run(); 2632 break; 2633 } 2634 2635 sm_timeout_start(connection); 2636 2637 // generate random number first, if we need to show passkey, otherwise send response 2638 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2639 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) connection->sm_handle); 2640 break; 2641 } 2642 2643 /* fall through */ 2644 2645 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2646 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2647 2648 // start with initiator key dist flags 2649 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2650 2651 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2652 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2653 if (setup->sm_use_secure_connections){ 2654 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2655 } 2656 #endif 2657 // setup in response 2658 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); 2659 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); 2660 2661 // update key distribution after ENC was dropped 2662 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2663 2664 if (setup->sm_use_secure_connections){ 2665 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2666 } else { 2667 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2668 } 2669 2670 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2671 sm_timeout_reset(connection); 2672 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2673 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 2674 sm_trigger_user_response(connection); 2675 } 2676 return; 2677 #endif 2678 2679 case SM_PH2_SEND_PAIRING_RANDOM: { 2680 uint8_t buffer[17]; 2681 buffer[0] = SM_CODE_PAIRING_RANDOM; 2682 reverse_128(setup->sm_local_random, &buffer[1]); 2683 if (IS_RESPONDER(connection->sm_role)){ 2684 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2685 } else { 2686 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2687 } 2688 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2689 sm_timeout_reset(connection); 2690 break; 2691 } 2692 2693 case SM_PH2_C1_GET_ENC_A: 2694 // already busy? 2695 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2696 // calculate confirm using aes128 engine - step 1 2697 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, sm_aes128_plaintext); 2698 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2699 sm_aes128_state = SM_AES128_ACTIVE; 2700 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_a, (void *)(uintptr_t) connection->sm_handle); 2701 break; 2702 2703 case SM_PH2_C1_GET_ENC_C: 2704 // already busy? 2705 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2706 // calculate m_confirm using aes128 engine - step 1 2707 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, sm_aes128_plaintext); 2708 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2709 sm_aes128_state = SM_AES128_ACTIVE; 2710 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_c, (void *)(uintptr_t) connection->sm_handle); 2711 break; 2712 2713 case SM_PH2_CALC_STK: 2714 // already busy? 2715 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2716 // calculate STK 2717 if (IS_RESPONDER(connection->sm_role)){ 2718 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2719 } else { 2720 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2721 } 2722 connection->sm_engine_state = SM_PH2_W4_STK; 2723 sm_aes128_state = SM_AES128_ACTIVE; 2724 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, (void *)(uintptr_t) connection->sm_handle); 2725 break; 2726 2727 case SM_PH3_Y_GET_ENC: 2728 // already busy? 2729 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2730 // PH3B2 - calculate Y from - enc 2731 2732 // dm helper (was sm_dm_r_prime) 2733 // r' = padding || r 2734 // r - 64 bit value 2735 memset(&sm_aes128_plaintext[0], 0, 8); 2736 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2737 2738 // Y = dm(DHK, Rand) 2739 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2740 sm_aes128_state = SM_AES128_ACTIVE; 2741 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_dhk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_ph3_y, (void *)(uintptr_t) connection->sm_handle); 2742 break; 2743 2744 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2745 uint8_t buffer[17]; 2746 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2747 reverse_128(setup->sm_local_confirm, &buffer[1]); 2748 if (IS_RESPONDER(connection->sm_role)){ 2749 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2750 } else { 2751 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2752 } 2753 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2754 sm_timeout_reset(connection); 2755 return; 2756 } 2757 #ifdef ENABLE_LE_PERIPHERAL 2758 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2759 sm_key_t stk_flipped; 2760 reverse_128(setup->sm_ltk, stk_flipped); 2761 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2762 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2763 return; 2764 } 2765 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2766 sm_key_t ltk_flipped; 2767 reverse_128(setup->sm_ltk, ltk_flipped); 2768 connection->sm_engine_state = SM_PH4_W4_CONNECTION_ENCRYPTED; 2769 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2770 return; 2771 } 2772 2773 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2774 // already busy? 2775 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2776 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2777 2778 sm_reset_setup(); 2779 sm_start_calculating_ltk_from_ediv_and_rand(connection); 2780 2781 sm_reencryption_started(connection); 2782 2783 // dm helper (was sm_dm_r_prime) 2784 // r' = padding || r 2785 // r - 64 bit value 2786 memset(&sm_aes128_plaintext[0], 0, 8); 2787 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2788 2789 // Y = dm(DHK, Rand) 2790 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 2791 sm_aes128_state = SM_AES128_ACTIVE; 2792 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_dhk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_enc_ph4_y, (void *)(uintptr_t) connection->sm_handle); 2793 return; 2794 #endif 2795 #ifdef ENABLE_LE_CENTRAL 2796 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2797 sm_key_t stk_flipped; 2798 reverse_128(setup->sm_ltk, stk_flipped); 2799 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2800 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2801 return; 2802 } 2803 #endif 2804 2805 case SM_PH3_DISTRIBUTE_KEYS: 2806 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2807 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2808 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2809 uint8_t buffer[17]; 2810 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2811 reverse_128(setup->sm_ltk, &buffer[1]); 2812 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2813 sm_timeout_reset(connection); 2814 return; 2815 } 2816 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2817 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2818 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2819 uint8_t buffer[11]; 2820 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2821 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2822 reverse_64(setup->sm_local_rand, &buffer[3]); 2823 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2824 sm_timeout_reset(connection); 2825 return; 2826 } 2827 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2828 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2829 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2830 uint8_t buffer[17]; 2831 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2832 reverse_128(sm_persistent_irk, &buffer[1]); 2833 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2834 sm_timeout_reset(connection); 2835 return; 2836 } 2837 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2838 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2839 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2840 bd_addr_t local_address; 2841 uint8_t buffer[8]; 2842 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2843 switch (gap_random_address_get_mode()){ 2844 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2845 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2846 // public or static random 2847 gap_le_get_own_address(&buffer[1], local_address); 2848 break; 2849 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2850 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2851 // fallback to public 2852 gap_local_bd_addr(local_address); 2853 buffer[1] = 0; 2854 break; 2855 default: 2856 btstack_assert(false); 2857 break; 2858 } 2859 reverse_bd_addr(local_address, &buffer[2]); 2860 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2861 sm_timeout_reset(connection); 2862 return; 2863 } 2864 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2865 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2866 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2867 2868 #ifdef ENABLE_LE_SIGNED_WRITE 2869 // hack to reproduce test runs 2870 if (test_use_fixed_local_csrk){ 2871 memset(setup->sm_local_csrk, 0xcc, 16); 2872 } 2873 2874 // store local CSRK 2875 if (setup->sm_le_device_index >= 0){ 2876 log_info("sm: store local CSRK"); 2877 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2878 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2879 } 2880 #endif 2881 2882 uint8_t buffer[17]; 2883 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2884 reverse_128(setup->sm_local_csrk, &buffer[1]); 2885 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2886 sm_timeout_reset(connection); 2887 return; 2888 } 2889 2890 // keys are sent 2891 if (IS_RESPONDER(connection->sm_role)){ 2892 // slave -> receive master keys if any 2893 if (sm_key_distribution_all_received(connection)){ 2894 sm_key_distribution_handle_all_received(connection); 2895 connection->sm_engine_state = SM_RESPONDER_IDLE; 2896 sm_pairing_complete(connection, ERROR_CODE_SUCCESS, 0); 2897 sm_done_for_handle(connection->sm_handle); 2898 } else { 2899 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2900 } 2901 } else { 2902 sm_master_pairing_success(connection); 2903 } 2904 break; 2905 2906 default: 2907 break; 2908 } 2909 2910 // check again if active connection was released 2911 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2912 } 2913 } 2914 2915 // sm_aes128_state stays active 2916 static void sm_handle_encryption_result_enc_a(void *arg){ 2917 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2918 sm_aes128_state = SM_AES128_IDLE; 2919 2920 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2921 if (connection == NULL) return; 2922 2923 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2924 sm_aes128_state = SM_AES128_ACTIVE; 2925 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, setup->sm_c1_t3_value, setup->sm_local_confirm, sm_handle_encryption_result_enc_b, (void *)(uintptr_t) connection->sm_handle); 2926 } 2927 2928 static void sm_handle_encryption_result_enc_b(void *arg){ 2929 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2930 sm_aes128_state = SM_AES128_IDLE; 2931 2932 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2933 if (connection == NULL) return; 2934 2935 log_info_key("c1!", setup->sm_local_confirm); 2936 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2937 sm_trigger_run(); 2938 } 2939 2940 // sm_aes128_state stays active 2941 static void sm_handle_encryption_result_enc_c(void *arg){ 2942 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2943 sm_aes128_state = SM_AES128_IDLE; 2944 2945 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2946 if (connection == NULL) return; 2947 2948 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2949 sm_aes128_state = SM_AES128_ACTIVE; 2950 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, setup->sm_c1_t3_value, sm_aes128_ciphertext, sm_handle_encryption_result_enc_d, (void *)(uintptr_t) connection->sm_handle); 2951 } 2952 2953 static void sm_handle_encryption_result_enc_d(void * arg){ 2954 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2955 sm_aes128_state = SM_AES128_IDLE; 2956 2957 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2958 if (connection == NULL) return; 2959 2960 log_info_key("c1!", sm_aes128_ciphertext); 2961 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 2962 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2963 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2964 sm_trigger_run(); 2965 return; 2966 } 2967 if (IS_RESPONDER(connection->sm_role)){ 2968 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2969 sm_trigger_run(); 2970 } else { 2971 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2972 sm_aes128_state = SM_AES128_ACTIVE; 2973 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, setup->sm_tk, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_stk, (void *)(uintptr_t) connection->sm_handle); 2974 } 2975 } 2976 2977 static void sm_handle_encryption_result_enc_stk(void *arg){ 2978 sm_aes128_state = SM_AES128_IDLE; 2979 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2980 2981 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2982 if (connection == NULL) return; 2983 2984 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2985 log_info_key("stk", setup->sm_ltk); 2986 if (IS_RESPONDER(connection->sm_role)){ 2987 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2988 } else { 2989 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2990 } 2991 sm_trigger_run(); 2992 } 2993 2994 // sm_aes128_state stays active 2995 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 2996 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2997 sm_aes128_state = SM_AES128_IDLE; 2998 2999 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3000 if (connection == NULL) return; 3001 3002 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3003 log_info_hex16("y", setup->sm_local_y); 3004 // PH3B3 - calculate EDIV 3005 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 3006 log_info_hex16("ediv", setup->sm_local_ediv); 3007 // PH3B4 - calculate LTK - enc 3008 // LTK = d1(ER, DIV, 0)) 3009 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3010 sm_aes128_state = SM_AES128_ACTIVE; 3011 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph3_ltk, (void *)(uintptr_t) connection->sm_handle); 3012 } 3013 3014 #ifdef ENABLE_LE_PERIPHERAL 3015 // sm_aes128_state stays active 3016 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 3017 sm_aes128_state = SM_AES128_IDLE; 3018 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3019 3020 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3021 if (connection == NULL) return; 3022 3023 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3024 log_info_hex16("y", setup->sm_local_y); 3025 3026 // PH3B3 - calculate DIV 3027 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 3028 log_info_hex16("ediv", setup->sm_local_ediv); 3029 // PH3B4 - calculate LTK - enc 3030 // LTK = d1(ER, DIV, 0)) 3031 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3032 sm_aes128_state = SM_AES128_ACTIVE; 3033 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph4_ltk, (void *)(uintptr_t) connection->sm_handle); 3034 } 3035 #endif 3036 3037 // sm_aes128_state stays active 3038 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 3039 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3040 sm_aes128_state = SM_AES128_IDLE; 3041 3042 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3043 if (connection == NULL) return; 3044 3045 log_info_key("ltk", setup->sm_ltk); 3046 // calc CSRK next 3047 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 3048 sm_aes128_state = SM_AES128_ACTIVE; 3049 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_local_csrk, sm_handle_encryption_result_enc_csrk, (void *)(uintptr_t) connection->sm_handle); 3050 } 3051 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 3052 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3053 // requirements to derive link key from LE: 3054 // - use secure connections 3055 if (setup->sm_use_secure_connections == 0) return false; 3056 // - bonding needs to be enabled: 3057 bool bonding_enabled = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) & sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_BONDING ) != 0u; 3058 if (!bonding_enabled) return false; 3059 // - need identity address 3060 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0); 3061 if (!have_identity_address_info) return false; 3062 // - there is no stored BR/EDR link key or the derived key has at least the same level of authentication (bail if stored key has higher authentication) 3063 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 3064 // If SC is authenticated, we consider it safe to overwrite a stored key. 3065 // If stored link key is not authenticated, it could already be compromised by a MITM attack. Allowing overwrite by unauthenticated derived key does not make it worse. 3066 uint8_t link_key[16]; 3067 link_key_type_t link_key_type; 3068 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 3069 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type) != 0; 3070 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 3071 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 3072 return false; 3073 } 3074 // get started (all of the above are true) 3075 return true; 3076 #else 3077 UNUSED(sm_connection); 3078 return false; 3079 #endif 3080 } 3081 3082 static void sm_handle_encryption_result_enc_csrk(void *arg){ 3083 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3084 sm_aes128_state = SM_AES128_IDLE; 3085 3086 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3087 if (connection == NULL) return; 3088 3089 sm_aes128_state = SM_AES128_IDLE; 3090 log_info_key("csrk", setup->sm_local_csrk); 3091 if (setup->sm_key_distribution_send_set){ 3092 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3093 } else { 3094 // no keys to send, just continue 3095 if (IS_RESPONDER(connection->sm_role)){ 3096 // slave -> receive master keys 3097 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3098 } else { 3099 if (sm_ctkd_from_le(connection)){ 3100 bool use_h7 = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) & sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_CT2) != 0; 3101 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 3102 } else { 3103 sm_master_pairing_success(connection); 3104 } 3105 } 3106 } 3107 sm_trigger_run(); 3108 } 3109 3110 #ifdef ENABLE_LE_PERIPHERAL 3111 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 3112 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3113 sm_aes128_state = SM_AES128_IDLE; 3114 3115 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3116 if (connection == NULL) return; 3117 3118 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3119 log_info_key("ltk", setup->sm_ltk); 3120 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 3121 sm_trigger_run(); 3122 } 3123 #endif 3124 3125 static void sm_handle_encryption_result_address_resolution(void *arg){ 3126 UNUSED(arg); 3127 sm_aes128_state = SM_AES128_IDLE; 3128 3129 sm_address_resolution_ah_calculation_active = 0; 3130 // compare calulated address against connecting device 3131 uint8_t * hash = &sm_aes128_ciphertext[13]; 3132 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3133 log_info("LE Device Lookup: matched resolvable private address"); 3134 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 3135 sm_trigger_run(); 3136 return; 3137 } 3138 // no match, try next 3139 sm_address_resolution_test++; 3140 sm_trigger_run(); 3141 } 3142 3143 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3144 UNUSED(arg); 3145 sm_aes128_state = SM_AES128_IDLE; 3146 3147 log_info_key("irk", sm_persistent_irk); 3148 dkg_state = DKG_CALC_DHK; 3149 sm_trigger_run(); 3150 } 3151 3152 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3153 UNUSED(arg); 3154 sm_aes128_state = SM_AES128_IDLE; 3155 3156 log_info_key("dhk", sm_persistent_dhk); 3157 dkg_state = DKG_READY; 3158 sm_trigger_run(); 3159 } 3160 3161 static void sm_handle_encryption_result_rau(void *arg){ 3162 UNUSED(arg); 3163 sm_aes128_state = SM_AES128_IDLE; 3164 3165 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3166 rau_state = RAU_SET_ADDRESS; 3167 sm_trigger_run(); 3168 } 3169 3170 static void sm_handle_random_result_rau(void * arg){ 3171 UNUSED(arg); 3172 // non-resolvable vs. resolvable 3173 switch (gap_random_adress_type){ 3174 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3175 // resolvable: use random as prand and calc address hash 3176 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3177 sm_random_address[0u] &= 0x3fu; 3178 sm_random_address[0u] |= 0x40u; 3179 rau_state = RAU_GET_ENC; 3180 break; 3181 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3182 default: 3183 // "The two most significant bits of the address shall be equal to ‘0’"" 3184 sm_random_address[0u] &= 0x3fu; 3185 rau_state = RAU_SET_ADDRESS; 3186 break; 3187 } 3188 sm_trigger_run(); 3189 } 3190 3191 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3192 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 3193 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3194 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3195 if (connection == NULL) return; 3196 3197 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3198 sm_trigger_run(); 3199 } 3200 3201 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3202 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3203 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3204 if (connection == NULL) return; 3205 3206 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3207 sm_trigger_run(); 3208 } 3209 #endif 3210 3211 static void sm_handle_random_result_ph2_random(void * arg){ 3212 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3213 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3214 if (connection == NULL) return; 3215 3216 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3217 sm_trigger_run(); 3218 } 3219 3220 static void sm_handle_random_result_ph2_tk(void * arg){ 3221 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3222 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3223 if (connection == NULL) return; 3224 3225 sm_reset_tk(); 3226 uint32_t tk; 3227 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 3228 // map random to 0-999999 without speding much cycles on a modulus operation 3229 tk = little_endian_read_32(sm_random_data,0); 3230 tk = tk & 0xfffff; // 1048575 3231 if (tk >= 999999u){ 3232 tk = tk - 999999u; 3233 } 3234 } else { 3235 // override with pre-defined passkey 3236 tk = sm_fixed_passkey_in_display_role; 3237 } 3238 big_endian_store_32(setup->sm_tk, 12, tk); 3239 if (IS_RESPONDER(connection->sm_role)){ 3240 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3241 } else { 3242 if (setup->sm_use_secure_connections){ 3243 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3244 } else { 3245 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3246 sm_trigger_user_response(connection); 3247 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3248 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3249 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) connection->sm_handle); 3250 } 3251 } 3252 } 3253 sm_trigger_run(); 3254 } 3255 3256 static void sm_handle_random_result_ph3_div(void * arg){ 3257 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3258 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3259 if (connection == NULL) return; 3260 3261 // use 16 bit from random value as div 3262 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3263 log_info_hex16("div", setup->sm_local_div); 3264 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3265 sm_trigger_run(); 3266 } 3267 3268 static void sm_handle_random_result_ph3_random(void * arg){ 3269 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3270 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3271 if (connection == NULL) return; 3272 3273 reverse_64(sm_random_data, setup->sm_local_rand); 3274 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3275 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3276 // no db for authenticated flag hack: store flag in bit 4 of LSB 3277 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3278 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3279 } 3280 static void sm_validate_er_ir(void){ 3281 // warn about default ER/IR 3282 int warning = 0; 3283 if (sm_ir_is_default()){ 3284 warning = 1; 3285 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3286 } 3287 if (sm_er_is_default()){ 3288 warning = 1; 3289 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3290 } 3291 if (warning) { 3292 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3293 } 3294 } 3295 3296 static void sm_handle_random_result_ir(void *arg){ 3297 sm_persistent_keys_random_active = 0; 3298 if (arg){ 3299 // key generated, store in tlv 3300 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3301 log_info("Generated IR key. Store in TLV status: %d", status); 3302 UNUSED(status); 3303 } 3304 log_info_key("IR", sm_persistent_ir); 3305 dkg_state = DKG_CALC_IRK; 3306 3307 if (test_use_fixed_local_irk){ 3308 log_info_key("IRK", sm_persistent_irk); 3309 dkg_state = DKG_CALC_DHK; 3310 } 3311 3312 sm_trigger_run(); 3313 } 3314 3315 static void sm_handle_random_result_er(void *arg){ 3316 sm_persistent_keys_random_active = 0; 3317 if (arg){ 3318 // key generated, store in tlv 3319 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3320 log_info("Generated ER key. Store in TLV status: %d", status); 3321 UNUSED(status); 3322 } 3323 log_info_key("ER", sm_persistent_er); 3324 3325 // try load ir 3326 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3327 if (key_size == 16){ 3328 // ok, let's continue 3329 log_info("IR from TLV"); 3330 sm_handle_random_result_ir( NULL ); 3331 } else { 3332 // invalid, generate new random one 3333 sm_persistent_keys_random_active = 1; 3334 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3335 } 3336 } 3337 3338 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3339 3340 UNUSED(channel); // ok: there is no channel 3341 UNUSED(size); // ok: fixed format HCI events 3342 3343 sm_connection_t * sm_conn; 3344 hci_con_handle_t con_handle; 3345 uint8_t status; 3346 switch (packet_type) { 3347 3348 case HCI_EVENT_PACKET: 3349 switch (hci_event_packet_get_type(packet)) { 3350 3351 case BTSTACK_EVENT_STATE: 3352 // bt stack activated, get started 3353 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3354 log_info("HCI Working!"); 3355 3356 // setup IR/ER with TLV 3357 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3358 if (sm_tlv_impl){ 3359 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3360 if (key_size == 16){ 3361 // ok, let's continue 3362 log_info("ER from TLV"); 3363 sm_handle_random_result_er( NULL ); 3364 } else { 3365 // invalid, generate random one 3366 sm_persistent_keys_random_active = 1; 3367 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3368 } 3369 } else { 3370 sm_validate_er_ir(); 3371 dkg_state = DKG_CALC_IRK; 3372 3373 if (test_use_fixed_local_irk){ 3374 log_info_key("IRK", sm_persistent_irk); 3375 dkg_state = DKG_CALC_DHK; 3376 } 3377 } 3378 3379 // restart random address updates after power cycle 3380 gap_random_address_set_mode(gap_random_adress_type); 3381 } 3382 break; 3383 3384 case HCI_EVENT_LE_META: 3385 switch (packet[2]) { 3386 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3387 3388 log_info("sm: connected"); 3389 3390 if (packet[3]) return; // connection failed 3391 3392 con_handle = little_endian_read_16(packet, 4); 3393 sm_conn = sm_get_connection_for_handle(con_handle); 3394 if (!sm_conn) break; 3395 3396 sm_conn->sm_handle = con_handle; 3397 sm_conn->sm_role = packet[6]; 3398 sm_conn->sm_peer_addr_type = packet[7]; 3399 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3400 3401 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3402 3403 // reset security properties 3404 sm_conn->sm_connection_encrypted = 0; 3405 sm_conn->sm_connection_authenticated = 0; 3406 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3407 sm_conn->sm_le_db_index = -1; 3408 sm_conn->sm_reencryption_active = false; 3409 3410 // prepare CSRK lookup (does not involve setup) 3411 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3412 3413 // just connected -> everything else happens in sm_run() 3414 if (IS_RESPONDER(sm_conn->sm_role)){ 3415 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3416 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3417 if (sm_slave_request_security) { 3418 // request security if requested by app 3419 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3420 } else { 3421 // otherwise, wait for pairing request 3422 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3423 } 3424 } 3425 break; 3426 } else { 3427 // master 3428 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3429 } 3430 break; 3431 3432 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3433 con_handle = little_endian_read_16(packet, 3); 3434 sm_conn = sm_get_connection_for_handle(con_handle); 3435 if (!sm_conn) break; 3436 3437 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3438 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3439 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3440 break; 3441 } 3442 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3443 // PH2 SEND LTK as we need to exchange keys in PH3 3444 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3445 break; 3446 } 3447 3448 // store rand and ediv 3449 reverse_64(&packet[5], sm_conn->sm_local_rand); 3450 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3451 3452 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3453 // potentially stored LTK is from the master 3454 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 3455 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3456 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3457 break; 3458 } 3459 // additionally check if remote is in LE Device DB if requested 3460 switch(sm_conn->sm_irk_lookup_state){ 3461 case IRK_LOOKUP_FAILED: 3462 log_info("LTK Request: device not in device db"); 3463 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3464 break; 3465 case IRK_LOOKUP_SUCCEEDED: 3466 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3467 break; 3468 default: 3469 // wait for irk look doen 3470 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3471 break; 3472 } 3473 break; 3474 } 3475 3476 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3477 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3478 #else 3479 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3480 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3481 #endif 3482 break; 3483 3484 default: 3485 break; 3486 } 3487 break; 3488 3489 case HCI_EVENT_ENCRYPTION_CHANGE: 3490 con_handle = hci_event_encryption_change_get_connection_handle(packet); 3491 sm_conn = sm_get_connection_for_handle(con_handle); 3492 if (!sm_conn) break; 3493 3494 sm_conn->sm_connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet); 3495 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3496 sm_conn->sm_actual_encryption_key_size); 3497 log_info("event handler, state %u", sm_conn->sm_engine_state); 3498 3499 switch (sm_conn->sm_engine_state){ 3500 3501 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3502 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3503 if (sm_conn->sm_connection_encrypted) { 3504 status = ERROR_CODE_SUCCESS; 3505 if (sm_conn->sm_role){ 3506 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3507 } else { 3508 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3509 } 3510 } else { 3511 status = ERROR_CODE_AUTHENTICATION_FAILURE; 3512 // set state to 'TIMEOUT' to prevent further interaction with this 3513 // also, gap_reconnect_security_setup_active will return true 3514 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 3515 } 3516 3517 // emit re-encryption complete 3518 sm_reencryption_complete(sm_conn, status); 3519 3520 // notify client, if pairing was requested before 3521 if (sm_conn->sm_pairing_requested){ 3522 sm_conn->sm_pairing_requested = 0; 3523 sm_pairing_complete(sm_conn, status, 0); 3524 } 3525 3526 sm_done_for_handle(sm_conn->sm_handle); 3527 3528 // abort/disconnect on authentication failure 3529 if (status == ERROR_CODE_AUTHENTICATION_FAILURE){ 3530 // gap disconnect with authentication failure 3531 hci_disconnect_security_block(con_handle); 3532 } 3533 break; 3534 3535 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3536 if (!sm_conn->sm_connection_encrypted) break; 3537 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3538 if (IS_RESPONDER(sm_conn->sm_role)){ 3539 // slave 3540 if (setup->sm_use_secure_connections){ 3541 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3542 } else { 3543 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); 3544 } 3545 } else { 3546 // master 3547 if (sm_key_distribution_all_received(sm_conn)){ 3548 // skip receiving keys as there are none 3549 sm_key_distribution_handle_all_received(sm_conn); 3550 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); 3551 } else { 3552 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3553 } 3554 } 3555 break; 3556 default: 3557 break; 3558 } 3559 break; 3560 3561 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3562 con_handle = little_endian_read_16(packet, 3); 3563 sm_conn = sm_get_connection_for_handle(con_handle); 3564 if (!sm_conn) break; 3565 3566 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3567 log_info("event handler, state %u", sm_conn->sm_engine_state); 3568 // continue if part of initial pairing 3569 switch (sm_conn->sm_engine_state){ 3570 case SM_PH4_W4_CONNECTION_ENCRYPTED: 3571 if (sm_conn->sm_role){ 3572 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3573 } else { 3574 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3575 } 3576 sm_done_for_handle(sm_conn->sm_handle); 3577 break; 3578 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3579 if (IS_RESPONDER(sm_conn->sm_role)){ 3580 // slave 3581 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); 3582 } else { 3583 // master 3584 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3585 } 3586 break; 3587 default: 3588 break; 3589 } 3590 break; 3591 3592 3593 case HCI_EVENT_DISCONNECTION_COMPLETE: 3594 con_handle = little_endian_read_16(packet, 3); 3595 sm_done_for_handle(con_handle); 3596 sm_conn = sm_get_connection_for_handle(con_handle); 3597 if (!sm_conn) break; 3598 3599 // pairing failed, if it was ongoing 3600 switch (sm_conn->sm_engine_state){ 3601 case SM_GENERAL_IDLE: 3602 case SM_INITIATOR_CONNECTED: 3603 case SM_RESPONDER_IDLE: 3604 break; 3605 default: 3606 sm_pairing_complete(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3607 break; 3608 } 3609 3610 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3611 sm_conn->sm_handle = 0; 3612 break; 3613 3614 case HCI_EVENT_COMMAND_COMPLETE: 3615 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3616 // set local addr for le device db 3617 bd_addr_t addr; 3618 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3619 le_device_db_set_local_bd_addr(addr); 3620 } 3621 break; 3622 default: 3623 break; 3624 } 3625 break; 3626 default: 3627 break; 3628 } 3629 3630 sm_run(); 3631 } 3632 3633 static inline int sm_calc_actual_encryption_key_size(int other){ 3634 if (other < sm_min_encryption_key_size) return 0; 3635 if (other < sm_max_encryption_key_size) return other; 3636 return sm_max_encryption_key_size; 3637 } 3638 3639 3640 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3641 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3642 switch (method){ 3643 case JUST_WORKS: 3644 case NUMERIC_COMPARISON: 3645 return 1; 3646 default: 3647 return 0; 3648 } 3649 } 3650 // responder 3651 3652 static int sm_passkey_used(stk_generation_method_t method){ 3653 switch (method){ 3654 case PK_RESP_INPUT: 3655 return 1; 3656 default: 3657 return 0; 3658 } 3659 } 3660 3661 static int sm_passkey_entry(stk_generation_method_t method){ 3662 switch (method){ 3663 case PK_RESP_INPUT: 3664 case PK_INIT_INPUT: 3665 case PK_BOTH_INPUT: 3666 return 1; 3667 default: 3668 return 0; 3669 } 3670 } 3671 3672 #endif 3673 3674 /** 3675 * @return ok 3676 */ 3677 static int sm_validate_stk_generation_method(void){ 3678 // check if STK generation method is acceptable by client 3679 switch (setup->sm_stk_generation_method){ 3680 case JUST_WORKS: 3681 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 3682 case PK_RESP_INPUT: 3683 case PK_INIT_INPUT: 3684 case PK_BOTH_INPUT: 3685 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 3686 case OOB: 3687 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 3688 case NUMERIC_COMPARISON: 3689 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 3690 default: 3691 return 0; 3692 } 3693 } 3694 3695 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3696 3697 // size of complete sm_pdu used to validate input 3698 static const uint8_t sm_pdu_size[] = { 3699 0, // 0x00 invalid opcode 3700 7, // 0x01 pairing request 3701 7, // 0x02 pairing response 3702 17, // 0x03 pairing confirm 3703 17, // 0x04 pairing random 3704 2, // 0x05 pairing failed 3705 17, // 0x06 encryption information 3706 11, // 0x07 master identification 3707 17, // 0x08 identification information 3708 8, // 0x09 identify address information 3709 17, // 0x0a signing information 3710 2, // 0x0b security request 3711 65, // 0x0c pairing public key 3712 17, // 0x0d pairing dhk check 3713 2, // 0x0e keypress notification 3714 }; 3715 3716 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 3717 sm_run(); 3718 } 3719 3720 if (packet_type != SM_DATA_PACKET) return; 3721 if (size == 0u) return; 3722 3723 uint8_t sm_pdu_code = packet[0]; 3724 3725 // validate pdu size 3726 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3727 if (sm_pdu_size[sm_pdu_code] != size) return; 3728 3729 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3730 if (!sm_conn) return; 3731 3732 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3733 sm_pairing_complete(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3734 sm_done_for_handle(con_handle); 3735 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3736 return; 3737 } 3738 3739 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3740 3741 int err; 3742 UNUSED(err); 3743 3744 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3745 uint8_t buffer[5]; 3746 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3747 buffer[1] = 3; 3748 little_endian_store_16(buffer, 2, con_handle); 3749 buffer[4] = packet[1]; 3750 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3751 return; 3752 } 3753 3754 switch (sm_conn->sm_engine_state){ 3755 3756 // a sm timeout requires a new physical connection 3757 case SM_GENERAL_TIMEOUT: 3758 return; 3759 3760 #ifdef ENABLE_LE_CENTRAL 3761 3762 // Initiator 3763 case SM_INITIATOR_CONNECTED: 3764 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3765 sm_pdu_received_in_wrong_state(sm_conn); 3766 break; 3767 } 3768 3769 // IRK complete? 3770 int have_ltk; 3771 uint8_t ltk[16]; 3772 switch (sm_conn->sm_irk_lookup_state){ 3773 case IRK_LOOKUP_FAILED: 3774 // start pairing 3775 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3776 break; 3777 case IRK_LOOKUP_SUCCEEDED: 3778 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 3779 have_ltk = !sm_is_null_key(ltk); 3780 log_info("central: security request - have_ltk %u", have_ltk); 3781 if (have_ltk){ 3782 // start re-encrypt 3783 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 3784 } else { 3785 // start pairing 3786 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3787 } 3788 break; 3789 default: 3790 // otherwise, store security request 3791 sm_conn->sm_security_request_received = 1; 3792 break; 3793 } 3794 break; 3795 3796 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3797 // Core 5, Vol 3, Part H, 2.4.6: 3798 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3799 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3800 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3801 log_info("Ignoring Security Request"); 3802 break; 3803 } 3804 3805 // all other pdus are incorrect 3806 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3807 sm_pdu_received_in_wrong_state(sm_conn); 3808 break; 3809 } 3810 3811 // store pairing request 3812 (void)memcpy(&setup->sm_s_pres, packet, 3813 sizeof(sm_pairing_packet_t)); 3814 err = sm_stk_generation_init(sm_conn); 3815 3816 #ifdef ENABLE_TESTING_SUPPORT 3817 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3818 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3819 err = test_pairing_failure; 3820 } 3821 #endif 3822 3823 if (err){ 3824 setup->sm_pairing_failed_reason = err; 3825 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3826 break; 3827 } 3828 3829 // generate random number first, if we need to show passkey 3830 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3831 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) sm_conn->sm_handle); 3832 break; 3833 } 3834 3835 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3836 if (setup->sm_use_secure_connections){ 3837 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3838 if (setup->sm_stk_generation_method == JUST_WORKS){ 3839 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3840 sm_trigger_user_response(sm_conn); 3841 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3842 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3843 } 3844 } else { 3845 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3846 } 3847 break; 3848 } 3849 #endif 3850 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3851 sm_trigger_user_response(sm_conn); 3852 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3853 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3854 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); 3855 } 3856 break; 3857 3858 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3859 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3860 sm_pdu_received_in_wrong_state(sm_conn); 3861 break; 3862 } 3863 3864 // store s_confirm 3865 reverse_128(&packet[1], setup->sm_peer_confirm); 3866 3867 #ifdef ENABLE_TESTING_SUPPORT 3868 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3869 log_info("testing_support: reset confirm value"); 3870 memset(setup->sm_peer_confirm, 0, 16); 3871 } 3872 #endif 3873 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3874 break; 3875 3876 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3877 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3878 sm_pdu_received_in_wrong_state(sm_conn); 3879 break;; 3880 } 3881 3882 // received random value 3883 reverse_128(&packet[1], setup->sm_peer_random); 3884 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3885 break; 3886 #endif 3887 3888 #ifdef ENABLE_LE_PERIPHERAL 3889 // Responder 3890 case SM_RESPONDER_IDLE: 3891 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3892 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3893 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3894 sm_pdu_received_in_wrong_state(sm_conn); 3895 break;; 3896 } 3897 3898 // store pairing request 3899 (void)memcpy(&sm_conn->sm_m_preq, packet, 3900 sizeof(sm_pairing_packet_t)); 3901 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3902 break; 3903 #endif 3904 3905 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3906 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3907 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3908 sm_pdu_received_in_wrong_state(sm_conn); 3909 break; 3910 } 3911 3912 // store public key for DH Key calculation 3913 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3914 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3915 3916 // validate public key 3917 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 3918 if (err){ 3919 log_error("sm: peer public key invalid %x", err); 3920 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 3921 break; 3922 } 3923 3924 // start calculating dhkey 3925 btstack_crypto_ecc_p256_calculate_dhkey(&sm_crypto_ecc_p256_request, setup->sm_peer_q, setup->sm_dhkey, sm_sc_dhkey_calculated, (void*)(uintptr_t) sm_conn->sm_handle); 3926 3927 3928 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3929 if (IS_RESPONDER(sm_conn->sm_role)){ 3930 // responder 3931 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3932 } else { 3933 // initiator 3934 // stk generation method 3935 // passkey entry: notify app to show passkey or to request passkey 3936 switch (setup->sm_stk_generation_method){ 3937 case JUST_WORKS: 3938 case NUMERIC_COMPARISON: 3939 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3940 break; 3941 case PK_RESP_INPUT: 3942 sm_sc_start_calculating_local_confirm(sm_conn); 3943 break; 3944 case PK_INIT_INPUT: 3945 case PK_BOTH_INPUT: 3946 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3947 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3948 break; 3949 } 3950 sm_sc_start_calculating_local_confirm(sm_conn); 3951 break; 3952 case OOB: 3953 // generate Nx 3954 log_info("Generate Na"); 3955 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_next_send_pairing_random, (void*)(uintptr_t) sm_conn->sm_handle); 3956 break; 3957 default: 3958 btstack_assert(false); 3959 break; 3960 } 3961 } 3962 break; 3963 3964 case SM_SC_W4_CONFIRMATION: 3965 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3966 sm_pdu_received_in_wrong_state(sm_conn); 3967 break; 3968 } 3969 // received confirm value 3970 reverse_128(&packet[1], setup->sm_peer_confirm); 3971 3972 #ifdef ENABLE_TESTING_SUPPORT 3973 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3974 log_info("testing_support: reset confirm value"); 3975 memset(setup->sm_peer_confirm, 0, 16); 3976 } 3977 #endif 3978 if (IS_RESPONDER(sm_conn->sm_role)){ 3979 // responder 3980 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3981 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3982 // still waiting for passkey 3983 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3984 break; 3985 } 3986 } 3987 sm_sc_start_calculating_local_confirm(sm_conn); 3988 } else { 3989 // initiator 3990 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3991 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_nonce, 16, &sm_handle_random_result_sc_next_send_pairing_random, (void*)(uintptr_t) sm_conn->sm_handle); 3992 } else { 3993 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3994 } 3995 } 3996 break; 3997 3998 case SM_SC_W4_PAIRING_RANDOM: 3999 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4000 sm_pdu_received_in_wrong_state(sm_conn); 4001 break; 4002 } 4003 4004 // received random value 4005 reverse_128(&packet[1], setup->sm_peer_nonce); 4006 4007 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 4008 // only check for JUST WORK/NC in initiator role OR passkey entry 4009 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 4010 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 4011 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 4012 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 4013 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 4014 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4015 break; 4016 } 4017 4018 // OOB 4019 if (setup->sm_stk_generation_method == OOB){ 4020 4021 // setup local random, set to zero if remote did not receive our data 4022 log_info("Received nonce, setup local random ra/rb for dhkey check"); 4023 if (IS_RESPONDER(sm_conn->sm_role)){ 4024 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u){ 4025 log_info("Reset rb as A does not have OOB data"); 4026 memset(setup->sm_rb, 0, 16); 4027 } else { 4028 (void)memcpy(setup->sm_rb, sm_sc_oob_random, 16); 4029 log_info("Use stored rb"); 4030 log_info_hexdump(setup->sm_rb, 16); 4031 } 4032 } else { 4033 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 4034 log_info("Reset ra as B does not have OOB data"); 4035 memset(setup->sm_ra, 0, 16); 4036 } else { 4037 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 4038 log_info("Use stored ra"); 4039 log_info_hexdump(setup->sm_ra, 16); 4040 } 4041 } 4042 4043 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 4044 if (setup->sm_have_oob_data){ 4045 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4046 break; 4047 } 4048 } 4049 4050 // TODO: we only get here for Responder role with JW/NC 4051 sm_sc_state_after_receiving_random(sm_conn); 4052 break; 4053 4054 case SM_SC_W2_CALCULATE_G2: 4055 case SM_SC_W4_CALCULATE_G2: 4056 case SM_SC_W4_CALCULATE_DHKEY: 4057 case SM_SC_W2_CALCULATE_F5_SALT: 4058 case SM_SC_W4_CALCULATE_F5_SALT: 4059 case SM_SC_W2_CALCULATE_F5_MACKEY: 4060 case SM_SC_W4_CALCULATE_F5_MACKEY: 4061 case SM_SC_W2_CALCULATE_F5_LTK: 4062 case SM_SC_W4_CALCULATE_F5_LTK: 4063 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 4064 case SM_SC_W4_DHKEY_CHECK_COMMAND: 4065 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 4066 case SM_SC_W4_USER_RESPONSE: 4067 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 4068 sm_pdu_received_in_wrong_state(sm_conn); 4069 break; 4070 } 4071 // store DHKey Check 4072 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 4073 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 4074 4075 // have we been only waiting for dhkey check command? 4076 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 4077 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 4078 } 4079 break; 4080 #endif 4081 4082 #ifdef ENABLE_LE_PERIPHERAL 4083 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 4084 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4085 sm_pdu_received_in_wrong_state(sm_conn); 4086 break; 4087 } 4088 4089 // received confirm value 4090 reverse_128(&packet[1], setup->sm_peer_confirm); 4091 4092 #ifdef ENABLE_TESTING_SUPPORT 4093 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4094 log_info("testing_support: reset confirm value"); 4095 memset(setup->sm_peer_confirm, 0, 16); 4096 } 4097 #endif 4098 // notify client to hide shown passkey 4099 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 4100 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 4101 } 4102 4103 // handle user cancel pairing? 4104 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 4105 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 4106 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 4107 break; 4108 } 4109 4110 // wait for user action? 4111 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 4112 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4113 break; 4114 } 4115 4116 // calculate and send local_confirm 4117 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); 4118 break; 4119 4120 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 4121 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4122 sm_pdu_received_in_wrong_state(sm_conn); 4123 break;; 4124 } 4125 4126 // received random value 4127 reverse_128(&packet[1], setup->sm_peer_random); 4128 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4129 break; 4130 #endif 4131 4132 case SM_PH3_RECEIVE_KEYS: 4133 switch(sm_pdu_code){ 4134 case SM_CODE_ENCRYPTION_INFORMATION: 4135 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 4136 reverse_128(&packet[1], setup->sm_peer_ltk); 4137 break; 4138 4139 case SM_CODE_MASTER_IDENTIFICATION: 4140 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 4141 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 4142 reverse_64(&packet[3], setup->sm_peer_rand); 4143 break; 4144 4145 case SM_CODE_IDENTITY_INFORMATION: 4146 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4147 reverse_128(&packet[1], setup->sm_peer_irk); 4148 break; 4149 4150 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4151 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4152 setup->sm_peer_addr_type = packet[1]; 4153 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4154 break; 4155 4156 case SM_CODE_SIGNING_INFORMATION: 4157 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4158 reverse_128(&packet[1], setup->sm_peer_csrk); 4159 break; 4160 default: 4161 // Unexpected PDU 4162 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4163 break; 4164 } 4165 // done with key distribution? 4166 if (sm_key_distribution_all_received(sm_conn)){ 4167 4168 sm_key_distribution_handle_all_received(sm_conn); 4169 4170 if (IS_RESPONDER(sm_conn->sm_role)){ 4171 if (sm_ctkd_from_le(sm_conn)){ 4172 bool use_h7 = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) & sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_CT2) != 0; 4173 sm_conn->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 4174 } else { 4175 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 4176 sm_pairing_complete(sm_conn, ERROR_CODE_SUCCESS, 0); 4177 sm_done_for_handle(sm_conn->sm_handle); 4178 } 4179 } else { 4180 if (setup->sm_use_secure_connections){ 4181 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4182 } else { 4183 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph3_random, (void *)(uintptr_t) sm_conn->sm_handle); 4184 } 4185 } 4186 } 4187 break; 4188 default: 4189 // Unexpected PDU 4190 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4191 break; 4192 } 4193 4194 // try to send next pdu 4195 sm_trigger_run(); 4196 } 4197 4198 // Security Manager Client API 4199 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 4200 sm_get_oob_data = get_oob_data_callback; 4201 } 4202 4203 void sm_register_sc_oob_data_callback( int (*get_sc_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_sc_peer_confirm, uint8_t * oob_sc_peer_random)){ 4204 sm_get_sc_oob_data = get_sc_oob_data_callback; 4205 } 4206 4207 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4208 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4209 } 4210 4211 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 4212 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 4213 } 4214 4215 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 4216 sm_min_encryption_key_size = min_size; 4217 sm_max_encryption_key_size = max_size; 4218 } 4219 4220 void sm_set_authentication_requirements(uint8_t auth_req){ 4221 #ifndef ENABLE_LE_SECURE_CONNECTIONS 4222 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 4223 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 4224 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 4225 } 4226 #endif 4227 sm_auth_req = auth_req; 4228 } 4229 4230 void sm_set_io_capabilities(io_capability_t io_capability){ 4231 sm_io_capabilities = io_capability; 4232 } 4233 4234 #ifdef ENABLE_LE_PERIPHERAL 4235 void sm_set_request_security(int enable){ 4236 sm_slave_request_security = enable; 4237 } 4238 #endif 4239 4240 void sm_set_er(sm_key_t er){ 4241 (void)memcpy(sm_persistent_er, er, 16); 4242 } 4243 4244 void sm_set_ir(sm_key_t ir){ 4245 (void)memcpy(sm_persistent_ir, ir, 16); 4246 } 4247 4248 // Testing support only 4249 void sm_test_set_irk(sm_key_t irk){ 4250 (void)memcpy(sm_persistent_irk, irk, 16); 4251 dkg_state = DKG_CALC_DHK; 4252 test_use_fixed_local_irk = true; 4253 } 4254 4255 void sm_test_use_fixed_local_csrk(void){ 4256 test_use_fixed_local_csrk = true; 4257 } 4258 4259 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4260 static void sm_ec_generated(void * arg){ 4261 UNUSED(arg); 4262 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4263 // trigger pairing if pending for ec key 4264 sm_trigger_run(); 4265 } 4266 static void sm_ec_generate_new_key(void){ 4267 log_info("sm: generate new ec key"); 4268 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 4269 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 4270 } 4271 #endif 4272 4273 #ifdef ENABLE_TESTING_SUPPORT 4274 void sm_test_set_pairing_failure(int reason){ 4275 test_pairing_failure = reason; 4276 } 4277 #endif 4278 4279 void sm_init(void){ 4280 // set default ER and IR values (should be unique - set by app or sm later using TLV) 4281 sm_er_ir_set_default(); 4282 4283 // defaults 4284 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4285 | SM_STK_GENERATION_METHOD_OOB 4286 | SM_STK_GENERATION_METHOD_PASSKEY 4287 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4288 4289 sm_max_encryption_key_size = 16; 4290 sm_min_encryption_key_size = 7; 4291 4292 sm_fixed_passkey_in_display_role = 0xffffffff; 4293 sm_reconstruct_ltk_without_le_device_db_entry = 1; 4294 4295 #ifdef USE_CMAC_ENGINE 4296 sm_cmac_active = 0; 4297 #endif 4298 dkg_state = DKG_W4_WORKING; 4299 rau_state = RAU_IDLE; 4300 sm_aes128_state = SM_AES128_IDLE; 4301 sm_address_resolution_test = -1; // no private address to resolve yet 4302 sm_address_resolution_ah_calculation_active = 0; 4303 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4304 sm_address_resolution_general_queue = NULL; 4305 4306 gap_random_adress_update_period = 15 * 60 * 1000L; 4307 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4308 4309 test_use_fixed_local_csrk = false; 4310 4311 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 4312 4313 // register for HCI Events from HCI 4314 hci_event_callback_registration.callback = &sm_event_packet_handler; 4315 hci_add_event_handler(&hci_event_callback_registration); 4316 4317 // 4318 btstack_crypto_init(); 4319 4320 // init le_device_db 4321 le_device_db_init(); 4322 4323 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4324 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4325 4326 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4327 sm_ec_generate_new_key(); 4328 #endif 4329 } 4330 4331 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4332 sm_fixed_passkey_in_display_role = passkey; 4333 } 4334 4335 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4336 sm_reconstruct_ltk_without_le_device_db_entry = allow; 4337 } 4338 4339 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4340 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4341 if (!hci_con) return NULL; 4342 return &hci_con->sm_connection; 4343 } 4344 4345 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 4346 switch (sm_conn->sm_engine_state){ 4347 case SM_GENERAL_IDLE: 4348 case SM_RESPONDER_IDLE: 4349 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4350 sm_trigger_run(); 4351 break; 4352 default: 4353 break; 4354 } 4355 } 4356 4357 /** 4358 * @brief Trigger Security Request 4359 */ 4360 void sm_send_security_request(hci_con_handle_t con_handle){ 4361 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4362 if (!sm_conn) return; 4363 sm_send_security_request_for_connection(sm_conn); 4364 } 4365 4366 // request pairing 4367 void sm_request_pairing(hci_con_handle_t con_handle){ 4368 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4369 if (!sm_conn) return; // wrong connection 4370 4371 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4372 if (IS_RESPONDER(sm_conn->sm_role)){ 4373 sm_send_security_request_for_connection(sm_conn); 4374 } else { 4375 // used as a trigger to start central/master/initiator security procedures 4376 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 4377 uint8_t ltk[16]; 4378 bool have_ltk; 4379 switch (sm_conn->sm_irk_lookup_state){ 4380 case IRK_LOOKUP_SUCCEEDED: 4381 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4382 have_ltk = !sm_is_null_key(ltk); 4383 log_info("have ltk %u", have_ltk); 4384 if (have_ltk){ 4385 sm_conn->sm_pairing_requested = 1; 4386 sm_conn->sm_engine_state = SM_INITIATOR_PH4_HAS_LTK; 4387 sm_reencryption_started(sm_conn); 4388 break; 4389 } 4390 /* fall through */ 4391 4392 case IRK_LOOKUP_FAILED: 4393 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4394 break; 4395 default: 4396 log_info("irk lookup pending"); 4397 sm_conn->sm_pairing_requested = 1; 4398 break; 4399 } 4400 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 4401 sm_conn->sm_pairing_requested = 1; 4402 } 4403 } 4404 sm_trigger_run(); 4405 } 4406 4407 // called by client app on authorization request 4408 void sm_authorization_decline(hci_con_handle_t con_handle){ 4409 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4410 if (!sm_conn) return; // wrong connection 4411 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4412 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4413 } 4414 4415 void sm_authorization_grant(hci_con_handle_t con_handle){ 4416 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4417 if (!sm_conn) return; // wrong connection 4418 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4419 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4420 } 4421 4422 // GAP Bonding API 4423 4424 void sm_bonding_decline(hci_con_handle_t con_handle){ 4425 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4426 if (!sm_conn) return; // wrong connection 4427 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4428 log_info("decline, state %u", sm_conn->sm_engine_state); 4429 switch(sm_conn->sm_engine_state){ 4430 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4431 case SM_SC_W4_USER_RESPONSE: 4432 case SM_SC_W4_CONFIRMATION: 4433 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4434 #endif 4435 case SM_PH1_W4_USER_RESPONSE: 4436 switch (setup->sm_stk_generation_method){ 4437 case PK_RESP_INPUT: 4438 case PK_INIT_INPUT: 4439 case PK_BOTH_INPUT: 4440 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4441 break; 4442 case NUMERIC_COMPARISON: 4443 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4444 break; 4445 case JUST_WORKS: 4446 case OOB: 4447 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4448 break; 4449 default: 4450 btstack_assert(false); 4451 break; 4452 } 4453 break; 4454 default: 4455 break; 4456 } 4457 sm_trigger_run(); 4458 } 4459 4460 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4461 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4462 if (!sm_conn) return; // wrong connection 4463 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4464 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4465 if (setup->sm_use_secure_connections){ 4466 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4467 } else { 4468 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); 4469 } 4470 } 4471 4472 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4473 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4474 sm_sc_prepare_dhkey_check(sm_conn); 4475 } 4476 #endif 4477 4478 sm_trigger_run(); 4479 } 4480 4481 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4482 // for now, it's the same 4483 sm_just_works_confirm(con_handle); 4484 } 4485 4486 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4487 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4488 if (!sm_conn) return; // wrong connection 4489 sm_reset_tk(); 4490 big_endian_store_32(setup->sm_tk, 12, passkey); 4491 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4492 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4493 btstack_crypto_random_generate(&sm_crypto_random_request, setup->sm_local_random, 16, &sm_handle_random_result_ph2_random, (void *)(uintptr_t) sm_conn->sm_handle); 4494 } 4495 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4496 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 4497 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 4498 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4499 sm_sc_start_calculating_local_confirm(sm_conn); 4500 } 4501 #endif 4502 sm_trigger_run(); 4503 } 4504 4505 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4506 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4507 if (!sm_conn) return; // wrong connection 4508 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4509 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4510 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 4511 switch (action){ 4512 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4513 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4514 flags |= (1u << action); 4515 break; 4516 case SM_KEYPRESS_PASSKEY_CLEARED: 4517 // clear counter, keypress & erased flags + set passkey cleared 4518 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 4519 break; 4520 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4521 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4522 // erase actions queued 4523 num_actions--; 4524 if (num_actions == 0u){ 4525 // clear counter, keypress & erased flags 4526 flags &= 0x19u; 4527 } 4528 break; 4529 } 4530 num_actions++; 4531 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4532 break; 4533 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4534 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4535 // enter actions queued 4536 num_actions--; 4537 if (num_actions == 0u){ 4538 // clear counter, keypress & erased flags 4539 flags &= 0x19u; 4540 } 4541 break; 4542 } 4543 num_actions++; 4544 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4545 break; 4546 default: 4547 break; 4548 } 4549 setup->sm_keypress_notification = (num_actions << 5) | flags; 4550 sm_trigger_run(); 4551 } 4552 4553 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4554 static void sm_handle_random_result_oob(void * arg){ 4555 UNUSED(arg); 4556 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4557 sm_trigger_run(); 4558 } 4559 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4560 4561 static btstack_crypto_random_t sm_crypto_random_oob_request; 4562 4563 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4564 sm_sc_oob_callback = callback; 4565 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4566 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4567 return 0; 4568 } 4569 #endif 4570 4571 /** 4572 * @brief Get Identity Resolving state 4573 * @param con_handle 4574 * @return irk_lookup_state_t 4575 */ 4576 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 4577 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4578 if (!sm_conn) return IRK_LOOKUP_IDLE; 4579 return sm_conn->sm_irk_lookup_state; 4580 } 4581 4582 /** 4583 * @brief Identify device in LE Device DB 4584 * @param handle 4585 * @returns index from le_device_db or -1 if not found/identified 4586 */ 4587 int sm_le_device_index(hci_con_handle_t con_handle ){ 4588 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4589 if (!sm_conn) return -1; 4590 return sm_conn->sm_le_db_index; 4591 } 4592 4593 static int gap_random_address_type_requires_updates(void){ 4594 switch (gap_random_adress_type){ 4595 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4596 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4597 return 0; 4598 default: 4599 return 1; 4600 } 4601 } 4602 4603 static uint8_t own_address_type(void){ 4604 switch (gap_random_adress_type){ 4605 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4606 return BD_ADDR_TYPE_LE_PUBLIC; 4607 default: 4608 return BD_ADDR_TYPE_LE_RANDOM; 4609 } 4610 } 4611 4612 // GAP LE API 4613 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4614 gap_random_address_update_stop(); 4615 gap_random_adress_type = random_address_type; 4616 hci_le_set_own_address_type(own_address_type()); 4617 if (!gap_random_address_type_requires_updates()) return; 4618 gap_random_address_update_start(); 4619 gap_random_address_trigger(); 4620 } 4621 4622 gap_random_address_type_t gap_random_address_get_mode(void){ 4623 return gap_random_adress_type; 4624 } 4625 4626 void gap_random_address_set_update_period(int period_ms){ 4627 gap_random_adress_update_period = period_ms; 4628 if (!gap_random_address_type_requires_updates()) return; 4629 gap_random_address_update_stop(); 4630 gap_random_address_update_start(); 4631 } 4632 4633 void gap_random_address_set(const bd_addr_t addr){ 4634 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4635 (void)memcpy(sm_random_address, addr, 6); 4636 rau_state = RAU_SET_ADDRESS; 4637 sm_trigger_run(); 4638 } 4639 4640 #ifdef ENABLE_LE_PERIPHERAL 4641 /* 4642 * @brief Set Advertisement Paramters 4643 * @param adv_int_min 4644 * @param adv_int_max 4645 * @param adv_type 4646 * @param direct_address_type 4647 * @param direct_address 4648 * @param channel_map 4649 * @param filter_policy 4650 * 4651 * @note own_address_type is used from gap_random_address_set_mode 4652 */ 4653 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4654 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4655 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4656 direct_address_typ, direct_address, channel_map, filter_policy); 4657 } 4658 #endif 4659 4660 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4661 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4662 // wrong connection 4663 if (!sm_conn) return 0; 4664 // already encrypted 4665 if (sm_conn->sm_connection_encrypted) return 0; 4666 // irk status? 4667 switch(sm_conn->sm_irk_lookup_state){ 4668 case IRK_LOOKUP_FAILED: 4669 // done, cannot setup encryption 4670 return 0; 4671 case IRK_LOOKUP_SUCCEEDED: 4672 break; 4673 default: 4674 // IR Lookup pending 4675 return 1; 4676 } 4677 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset 4678 if (sm_conn->sm_role){ 4679 return sm_conn->sm_engine_state != SM_RESPONDER_IDLE; 4680 } else { 4681 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4682 } 4683 } 4684 4685 void sm_set_secure_connections_only_mode(bool enable){ 4686 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4687 sm_sc_only_mode = enable; 4688 #else 4689 // SC Only mode not possible without support for SC 4690 btstack_assert(enable == false); 4691 #endif 4692 } 4693 4694 const uint8_t * gap_get_persistent_irk(void){ 4695 return sm_persistent_irk; 4696 } 4697 4698 void gap_delete_bonding(bd_addr_type_t address_type, bd_addr_t address){ 4699 uint16_t i; 4700 for (i=0; i < le_device_db_max_count(); i++){ 4701 bd_addr_t entry_address; 4702 int entry_address_type = BD_ADDR_TYPE_UNKNOWN; 4703 le_device_db_info(i, &entry_address_type, entry_address, NULL); 4704 // skip unused entries 4705 if (entry_address_type == (int) BD_ADDR_TYPE_UNKNOWN) continue; 4706 if ((entry_address_type == (int) address_type) && (memcmp(entry_address, address, 6) == 0)){ 4707 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 4708 hci_remove_le_device_db_entry_from_resolving_list(i); 4709 #endif 4710 le_device_db_remove(i); 4711 break; 4712 } 4713 } 4714 } 4715