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) 64 #error "Cross Transport Key Derivation requires BR/EDR (Classic) support" 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_SUCEEDED, 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 373 374 } sm_setup_context_t; 375 376 // 377 static sm_setup_context_t the_setup; 378 static sm_setup_context_t * setup = &the_setup; 379 380 // active connection - the one for which the_setup is used for 381 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 382 383 // @returns 1 if oob data is available 384 // stores oob data in provided 16 byte buffer if not null 385 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 386 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); 387 388 static void sm_run(void); 389 static void sm_done_for_handle(hci_con_handle_t con_handle); 390 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 391 static inline int sm_calc_actual_encryption_key_size(int other); 392 static int sm_validate_stk_generation_method(void); 393 static void sm_handle_encryption_result_address_resolution(void *arg); 394 static void sm_handle_encryption_result_dkg_dhk(void *arg); 395 static void sm_handle_encryption_result_dkg_irk(void *arg); 396 static void sm_handle_encryption_result_enc_a(void *arg); 397 static void sm_handle_encryption_result_enc_b(void *arg); 398 static void sm_handle_encryption_result_enc_c(void *arg); 399 static void sm_handle_encryption_result_enc_csrk(void *arg); 400 static void sm_handle_encryption_result_enc_d(void * arg); 401 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 402 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 403 #ifdef ENABLE_LE_PERIPHERAL 404 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 405 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 406 #endif 407 static void sm_handle_encryption_result_enc_stk(void *arg); 408 static void sm_handle_encryption_result_rau(void *arg); 409 static void sm_handle_random_result_ph2_tk(void * arg); 410 static void sm_handle_random_result_rau(void * arg); 411 #ifdef ENABLE_LE_SECURE_CONNECTIONS 412 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)); 413 static void sm_ec_generate_new_key(void); 414 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg); 415 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); 416 static int sm_passkey_entry(stk_generation_method_t method); 417 #endif 418 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 419 420 static void log_info_hex16(const char * name, uint16_t value){ 421 log_info("%-6s 0x%04x", name, value); 422 } 423 424 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 425 // return packet[0]; 426 // } 427 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 428 return packet[1]; 429 } 430 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 431 return packet[2]; 432 } 433 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 434 return packet[3]; 435 } 436 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 437 return packet[4]; 438 } 439 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 440 return packet[5]; 441 } 442 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 443 return packet[6]; 444 } 445 446 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 447 packet[0] = code; 448 } 449 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 450 packet[1] = io_capability; 451 } 452 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 453 packet[2] = oob_data_flag; 454 } 455 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 456 packet[3] = auth_req; 457 } 458 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 459 packet[4] = max_encryption_key_size; 460 } 461 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 462 packet[5] = initiator_key_distribution; 463 } 464 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 465 packet[6] = responder_key_distribution; 466 } 467 468 // @returns 1 if all bytes are 0 469 static int sm_is_null(uint8_t * data, int size){ 470 int i; 471 for (i=0; i < size ; i++){ 472 if (data[i] != 0) { 473 return 0; 474 } 475 } 476 return 1; 477 } 478 479 static int sm_is_null_random(uint8_t random[8]){ 480 return sm_is_null(random, 8); 481 } 482 483 static int sm_is_null_key(uint8_t * key){ 484 return sm_is_null(key, 16); 485 } 486 487 // sm_trigger_run allows to schedule callback from main run loop // reduces stack depth 488 static void sm_run_timer_handler(btstack_timer_source_t * ts){ 489 UNUSED(ts); 490 sm_run(); 491 } 492 static void sm_trigger_run(void){ 493 (void)btstack_run_loop_remove_timer(&sm_run_timer); 494 btstack_run_loop_set_timer(&sm_run_timer, 0); 495 btstack_run_loop_add_timer(&sm_run_timer); 496 } 497 498 // Key utils 499 static void sm_reset_tk(void){ 500 int i; 501 for (i=0;i<16;i++){ 502 setup->sm_tk[i] = 0; 503 } 504 } 505 506 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 507 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 508 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 509 int i; 510 for (i = max_encryption_size ; i < 16 ; i++){ 511 key[15-i] = 0; 512 } 513 } 514 515 // ER / IR checks 516 static void sm_er_ir_set_default(void){ 517 int i; 518 for (i=0;i<16;i++){ 519 sm_persistent_er[i] = 0x30 + i; 520 sm_persistent_ir[i] = 0x90 + i; 521 } 522 } 523 524 static int sm_er_is_default(void){ 525 int i; 526 for (i=0;i<16;i++){ 527 if (sm_persistent_er[i] != (0x30+i)) return 0; 528 } 529 return 1; 530 } 531 532 static int sm_ir_is_default(void){ 533 int i; 534 for (i=0;i<16;i++){ 535 if (sm_persistent_ir[i] != (0x90+i)) return 0; 536 } 537 return 1; 538 } 539 540 // SMP Timeout implementation 541 542 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 543 // the Security Manager Timer shall be reset and started. 544 // 545 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 546 // 547 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 548 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 549 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 550 // established. 551 552 static void sm_timeout_handler(btstack_timer_source_t * timer){ 553 log_info("SM timeout"); 554 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 555 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 556 sm_notify_client_status_reason(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 557 sm_done_for_handle(sm_conn->sm_handle); 558 559 // trigger handling of next ready connection 560 sm_run(); 561 } 562 static void sm_timeout_start(sm_connection_t * sm_conn){ 563 btstack_run_loop_remove_timer(&setup->sm_timeout); 564 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 565 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 566 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 567 btstack_run_loop_add_timer(&setup->sm_timeout); 568 } 569 static void sm_timeout_stop(void){ 570 btstack_run_loop_remove_timer(&setup->sm_timeout); 571 } 572 static void sm_timeout_reset(sm_connection_t * sm_conn){ 573 sm_timeout_stop(); 574 sm_timeout_start(sm_conn); 575 } 576 577 // end of sm timeout 578 579 // GAP Random Address updates 580 static gap_random_address_type_t gap_random_adress_type; 581 static btstack_timer_source_t gap_random_address_update_timer; 582 static uint32_t gap_random_adress_update_period; 583 584 static void gap_random_address_trigger(void){ 585 log_info("gap_random_address_trigger, state %u", rau_state); 586 if (rau_state != RAU_IDLE) return; 587 rau_state = RAU_GET_RANDOM; 588 sm_trigger_run(); 589 } 590 591 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 592 UNUSED(timer); 593 594 log_info("GAP Random Address Update due"); 595 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 596 btstack_run_loop_add_timer(&gap_random_address_update_timer); 597 gap_random_address_trigger(); 598 } 599 600 static void gap_random_address_update_start(void){ 601 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 602 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 603 btstack_run_loop_add_timer(&gap_random_address_update_timer); 604 } 605 606 static void gap_random_address_update_stop(void){ 607 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 608 } 609 610 // ah(k,r) helper 611 // r = padding || r 612 // r - 24 bit value 613 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 614 // r'= padding || r 615 memset(r_prime, 0, 16); 616 (void)memcpy(&r_prime[13], r, 3); 617 } 618 619 // d1 helper 620 // d' = padding || r || d 621 // d,r - 16 bit values 622 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 623 // d'= padding || r || d 624 memset(d1_prime, 0, 16); 625 big_endian_store_16(d1_prime, 12, r); 626 big_endian_store_16(d1_prime, 14, d); 627 } 628 629 // calculate arguments for first AES128 operation in C1 function 630 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){ 631 632 // p1 = pres || preq || rat’ || iat’ 633 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 634 // cant octet of pres becomes the most significant octet of p1. 635 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 636 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 637 // p1 is 0x05000800000302070710000001010001." 638 639 sm_key_t p1; 640 reverse_56(pres, &p1[0]); 641 reverse_56(preq, &p1[7]); 642 p1[14] = rat; 643 p1[15] = iat; 644 log_info_key("p1", p1); 645 log_info_key("r", r); 646 647 // t1 = r xor p1 648 int i; 649 for (i=0;i<16;i++){ 650 t1[i] = r[i] ^ p1[i]; 651 } 652 log_info_key("t1", t1); 653 } 654 655 // calculate arguments for second AES128 operation in C1 function 656 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 657 // p2 = padding || ia || ra 658 // "The least significant octet of ra becomes the least significant octet of p2 and 659 // the most significant octet of padding becomes the most significant octet of p2. 660 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 661 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 662 663 sm_key_t p2; 664 memset(p2, 0, 16); 665 (void)memcpy(&p2[4], ia, 6); 666 (void)memcpy(&p2[10], ra, 6); 667 log_info_key("p2", p2); 668 669 // c1 = e(k, t2_xor_p2) 670 int i; 671 for (i=0;i<16;i++){ 672 t3[i] = t2[i] ^ p2[i]; 673 } 674 log_info_key("t3", t3); 675 } 676 677 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 678 log_info_key("r1", r1); 679 log_info_key("r2", r2); 680 (void)memcpy(&r_prime[8], &r2[8], 8); 681 (void)memcpy(&r_prime[0], &r1[8], 8); 682 } 683 684 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 685 UNUSED(channel); 686 687 // log event 688 hci_dump_packet(packet_type, 1, packet, size); 689 // dispatch to all event handlers 690 btstack_linked_list_iterator_t it; 691 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 692 while (btstack_linked_list_iterator_has_next(&it)){ 693 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 694 entry->callback(packet_type, 0, packet, size); 695 } 696 } 697 698 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){ 699 event[0] = type; 700 event[1] = event_size - 2; 701 little_endian_store_16(event, 2, con_handle); 702 event[4] = addr_type; 703 reverse_bd_addr(address, &event[5]); 704 } 705 706 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 707 uint8_t event[11]; 708 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 709 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 710 } 711 712 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){ 713 uint8_t event[15]; 714 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 715 little_endian_store_32(event, 11, passkey); 716 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 717 } 718 719 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){ 720 // fetch addr and addr type from db, only called for valid entries 721 bd_addr_t identity_address; 722 int identity_address_type; 723 le_device_db_info(index, &identity_address_type, identity_address, NULL); 724 725 uint8_t event[20]; 726 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 727 event[11] = identity_address_type; 728 reverse_bd_addr(identity_address, &event[12]); 729 little_endian_store_16(event, 18, index); 730 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 731 } 732 733 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){ 734 uint8_t event[12]; 735 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 736 event[11] = status; 737 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 738 } 739 740 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 741 uint8_t event[13]; 742 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 743 event[11] = status; 744 event[12] = reason; 745 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 746 } 747 748 // decide on stk generation based on 749 // - pairing request 750 // - io capabilities 751 // - OOB data availability 752 static void sm_setup_tk(void){ 753 754 // horizontal: initiator capabilities 755 // vertial: responder capabilities 756 static const stk_generation_method_t stk_generation_method [5] [5] = { 757 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 758 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 759 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 760 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 761 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 762 }; 763 764 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 765 #ifdef ENABLE_LE_SECURE_CONNECTIONS 766 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 767 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 768 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 769 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 770 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 771 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 772 }; 773 #endif 774 775 // default: just works 776 setup->sm_stk_generation_method = JUST_WORKS; 777 778 #ifdef ENABLE_LE_SECURE_CONNECTIONS 779 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 780 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 781 & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; 782 #else 783 setup->sm_use_secure_connections = 0; 784 #endif 785 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 786 787 788 // decide if OOB will be used based on SC vs. Legacy and oob flags 789 int use_oob = 0; 790 if (setup->sm_use_secure_connections){ 791 // In LE Secure Connections pairing, the out of band method is used if at least 792 // one device has the peer device's out of band authentication data available. 793 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 794 } else { 795 // In LE legacy pairing, the out of band method is used if both the devices have 796 // the other device's out of band authentication data available. 797 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 798 } 799 if (use_oob){ 800 log_info("SM: have OOB data"); 801 log_info_key("OOB", setup->sm_tk); 802 setup->sm_stk_generation_method = OOB; 803 return; 804 } 805 806 // If both devices have not set the MITM option in the Authentication Requirements 807 // Flags, then the IO capabilities shall be ignored and the Just Works association 808 // model shall be used. 809 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) 810 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ 811 log_info("SM: MITM not required by both -> JUST WORKS"); 812 return; 813 } 814 815 // Reset TK as it has been setup in sm_init_setup 816 sm_reset_tk(); 817 818 // Also use just works if unknown io capabilites 819 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)){ 820 return; 821 } 822 823 // Otherwise the IO capabilities of the devices shall be used to determine the 824 // pairing method as defined in Table 2.4. 825 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 826 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 827 828 #ifdef ENABLE_LE_SECURE_CONNECTIONS 829 // table not define by default 830 if (setup->sm_use_secure_connections){ 831 generation_method = stk_generation_method_with_secure_connection; 832 } 833 #endif 834 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)]; 835 836 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 837 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); 838 } 839 840 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 841 int flags = 0; 842 if (key_set & SM_KEYDIST_ENC_KEY){ 843 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 844 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 845 } 846 if (key_set & SM_KEYDIST_ID_KEY){ 847 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 848 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 849 } 850 if (key_set & SM_KEYDIST_SIGN){ 851 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 852 } 853 return flags; 854 } 855 856 static void sm_setup_key_distribution(uint8_t key_set){ 857 setup->sm_key_distribution_received_set = 0; 858 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 859 setup->sm_key_distribution_sent_set = 0; 860 #ifdef ENABLE_LE_SIGNED_WRITE 861 setup->sm_le_device_index = -1; 862 #endif 863 } 864 865 // CSRK Key Lookup 866 867 868 static int sm_address_resolution_idle(void){ 869 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 870 } 871 872 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){ 873 (void)memcpy(sm_address_resolution_address, addr, 6); 874 sm_address_resolution_addr_type = addr_type; 875 sm_address_resolution_test = 0; 876 sm_address_resolution_mode = mode; 877 sm_address_resolution_context = context; 878 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 879 } 880 881 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 882 // check if already in list 883 btstack_linked_list_iterator_t it; 884 sm_lookup_entry_t * entry; 885 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 886 while(btstack_linked_list_iterator_has_next(&it)){ 887 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 888 if (entry->address_type != address_type) continue; 889 if (memcmp(entry->address, address, 6)) continue; 890 // already in list 891 return BTSTACK_BUSY; 892 } 893 entry = btstack_memory_sm_lookup_entry_get(); 894 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 895 entry->address_type = (bd_addr_type_t) address_type; 896 (void)memcpy(entry->address, address, 6); 897 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 898 sm_trigger_run(); 899 return 0; 900 } 901 902 // CMAC calculation using AES Engineq 903 #ifdef USE_CMAC_ENGINE 904 905 static void sm_cmac_done_trampoline(void * arg){ 906 UNUSED(arg); 907 sm_cmac_active = 0; 908 (*sm_cmac_done_callback)(sm_cmac_hash); 909 sm_trigger_run(); 910 } 911 912 int sm_cmac_ready(void){ 913 return sm_cmac_active == 0u; 914 } 915 #endif 916 917 #ifdef ENABLE_LE_SECURE_CONNECTIONS 918 // generic cmac calculation 919 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)){ 920 sm_cmac_active = 1; 921 sm_cmac_done_callback = done_callback; 922 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 923 } 924 #endif 925 926 // cmac for ATT Message signing 927 #ifdef ENABLE_LE_SIGNED_WRITE 928 929 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)){ 930 sm_cmac_active = 1; 931 sm_cmac_done_callback = done_callback; 932 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 933 } 934 935 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 936 if (offset >= sm_cmac_signed_write_message_len) { 937 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 938 return 0; 939 } 940 941 offset = sm_cmac_signed_write_message_len - 1 - offset; 942 943 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 944 if (offset < 3){ 945 return sm_cmac_signed_write_header[offset]; 946 } 947 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 948 if (offset < actual_message_len_incl_header){ 949 return sm_cmac_signed_write_message[offset - 3]; 950 } 951 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 952 } 953 954 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)){ 955 // ATT Message Signing 956 sm_cmac_signed_write_header[0] = opcode; 957 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 958 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 959 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 960 sm_cmac_signed_write_message = message; 961 sm_cmac_signed_write_message_len = total_message_len; 962 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 963 } 964 #endif 965 966 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 967 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 968 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 969 switch (setup->sm_stk_generation_method){ 970 case PK_RESP_INPUT: 971 if (IS_RESPONDER(sm_conn->sm_role)){ 972 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 973 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 974 } else { 975 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)); 976 } 977 break; 978 case PK_INIT_INPUT: 979 if (IS_RESPONDER(sm_conn->sm_role)){ 980 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)); 981 } else { 982 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 983 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 984 } 985 break; 986 case PK_BOTH_INPUT: 987 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 988 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 989 break; 990 case NUMERIC_COMPARISON: 991 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 992 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)); 993 break; 994 case JUST_WORKS: 995 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 996 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 997 break; 998 case OOB: 999 // client already provided OOB data, let's skip notification. 1000 break; 1001 } 1002 } 1003 1004 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1005 int recv_flags; 1006 if (IS_RESPONDER(sm_conn->sm_role)){ 1007 // slave / responder 1008 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1009 } else { 1010 // master / initiator 1011 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1012 } 1013 1014 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1015 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1016 if (setup->sm_use_secure_connections){ 1017 recv_flags &= ~(SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION | SM_KEYDIST_FLAG_MASTER_IDENTIFICATION); 1018 } 1019 #endif 1020 1021 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1022 return (setup->sm_key_distribution_received_set & recv_flags) == recv_flags; 1023 } 1024 1025 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1026 if (sm_active_connection_handle == con_handle){ 1027 sm_timeout_stop(); 1028 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1029 log_info("sm: connection 0x%x released setup context", con_handle); 1030 1031 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1032 // generate new ec key after each pairing (that used it) 1033 if (setup->sm_use_secure_connections){ 1034 sm_ec_generate_new_key(); 1035 } 1036 #endif 1037 } 1038 } 1039 1040 static void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done 1041 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1042 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 1043 sm_done_for_handle(connection->sm_handle); 1044 } 1045 1046 static int sm_key_distribution_flags_for_auth_req(void){ 1047 1048 int flags = SM_KEYDIST_ID_KEY; 1049 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1050 // encryption and signing information only if bonding requested 1051 flags |= SM_KEYDIST_ENC_KEY; 1052 #ifdef ENABLE_LE_SIGNED_WRITE 1053 flags |= SM_KEYDIST_SIGN; 1054 #endif 1055 } 1056 return flags; 1057 } 1058 1059 static void sm_reset_setup(void){ 1060 // fill in sm setup 1061 setup->sm_state_vars = 0; 1062 setup->sm_keypress_notification = 0; 1063 sm_reset_tk(); 1064 } 1065 1066 static void sm_init_setup(sm_connection_t * sm_conn){ 1067 1068 // fill in sm setup 1069 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1070 (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1071 1072 // query client for Legacy Pairing OOB data 1073 setup->sm_have_oob_data = 0; 1074 if (sm_get_oob_data) { 1075 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1076 } 1077 1078 // if available and SC supported, also ask for SC OOB Data 1079 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1080 memset(setup->sm_ra, 0, 16); 1081 memset(setup->sm_rb, 0, 16); 1082 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1083 if (sm_get_sc_oob_data){ 1084 if (IS_RESPONDER(sm_conn->sm_role)){ 1085 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1086 sm_conn->sm_peer_addr_type, 1087 sm_conn->sm_peer_address, 1088 setup->sm_peer_confirm, 1089 setup->sm_ra); 1090 } else { 1091 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1092 sm_conn->sm_peer_addr_type, 1093 sm_conn->sm_peer_address, 1094 setup->sm_peer_confirm, 1095 setup->sm_rb); 1096 } 1097 } else { 1098 setup->sm_have_oob_data = 0; 1099 } 1100 } 1101 #endif 1102 1103 sm_pairing_packet_t * local_packet; 1104 if (IS_RESPONDER(sm_conn->sm_role)){ 1105 // slave 1106 local_packet = &setup->sm_s_pres; 1107 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1108 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1109 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1110 } else { 1111 // master 1112 local_packet = &setup->sm_m_preq; 1113 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1114 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1115 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1116 1117 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1118 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1119 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1120 } 1121 1122 uint8_t auth_req = sm_auth_req; 1123 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1124 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1125 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1126 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1127 } 1128 1129 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1130 1131 sm_pairing_packet_t * remote_packet; 1132 int remote_key_request; 1133 if (IS_RESPONDER(sm_conn->sm_role)){ 1134 // slave / responder 1135 remote_packet = &setup->sm_m_preq; 1136 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1137 } else { 1138 // master / initiator 1139 remote_packet = &setup->sm_s_pres; 1140 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1141 } 1142 1143 // check key size 1144 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1145 if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; 1146 1147 // decide on STK generation method / SC 1148 sm_setup_tk(); 1149 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1150 1151 // check if STK generation method is acceptable by client 1152 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1153 1154 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1155 // check LE SC Only mode 1156 if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ 1157 log_info("SC Only mode active but SC not possible"); 1158 return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1159 } 1160 1161 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1162 if (setup->sm_use_secure_connections){ 1163 remote_key_request &= ~SM_KEYDIST_ENC_KEY; 1164 } 1165 #endif 1166 1167 // identical to responder 1168 sm_setup_key_distribution(remote_key_request); 1169 1170 // JUST WORKS doens't provide authentication 1171 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1172 1173 return 0; 1174 } 1175 1176 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1177 1178 // cache and reset context 1179 int matched_device_id = sm_address_resolution_test; 1180 address_resolution_mode_t mode = sm_address_resolution_mode; 1181 void * context = sm_address_resolution_context; 1182 1183 // reset context 1184 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1185 sm_address_resolution_context = NULL; 1186 sm_address_resolution_test = -1; 1187 hci_con_handle_t con_handle = 0; 1188 1189 sm_connection_t * sm_connection; 1190 #ifdef ENABLE_LE_CENTRAL 1191 sm_key_t ltk; 1192 int have_ltk; 1193 int pairing_need; 1194 #endif 1195 switch (mode){ 1196 case ADDRESS_RESOLUTION_GENERAL: 1197 break; 1198 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1199 sm_connection = (sm_connection_t *) context; 1200 con_handle = sm_connection->sm_handle; 1201 switch (event){ 1202 case ADDRESS_RESOLUTION_SUCEEDED: 1203 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1204 sm_connection->sm_le_db_index = matched_device_id; 1205 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1206 if (sm_connection->sm_role) { 1207 // LTK request received before, IRK required -> start LTK calculation 1208 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1209 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1210 } 1211 break; 1212 } 1213 #ifdef ENABLE_LE_CENTRAL 1214 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1215 have_ltk = !sm_is_null_key(ltk); 1216 pairing_need = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1217 log_info("central: pairing request local %u, remote %u => action %u. have_ltk %u", 1218 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, pairing_need, have_ltk); 1219 // reset requests 1220 sm_connection->sm_security_request_received = 0; 1221 sm_connection->sm_pairing_requested = 0; 1222 1223 // have ltk -> start encryption 1224 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1225 // "When a bond has been created between two devices, any reconnection should result in the local device 1226 // enabling or requesting encryption with the remote device before initiating any service request." 1227 if (have_ltk){ 1228 #ifdef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 1229 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1230 break; 1231 #else 1232 log_info("central: defer enabling encryption for bonded device"); 1233 #endif 1234 } 1235 // pairint_request -> send pairing request 1236 if (pairing_need){ 1237 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1238 break; 1239 } 1240 #endif 1241 break; 1242 case ADDRESS_RESOLUTION_FAILED: 1243 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1244 if (sm_connection->sm_role) { 1245 // LTK request received before, IRK required -> negative LTK reply 1246 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1247 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1248 } 1249 break; 1250 } 1251 #ifdef ENABLE_LE_CENTRAL 1252 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1253 sm_connection->sm_security_request_received = 0; 1254 sm_connection->sm_pairing_requested = 0; 1255 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1256 #endif 1257 break; 1258 } 1259 break; 1260 default: 1261 break; 1262 } 1263 1264 switch (event){ 1265 case ADDRESS_RESOLUTION_SUCEEDED: 1266 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1267 break; 1268 case ADDRESS_RESOLUTION_FAILED: 1269 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1270 break; 1271 } 1272 } 1273 1274 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1275 1276 int le_db_index = -1; 1277 1278 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1279 int bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1280 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1281 & SM_AUTHREQ_BONDING ) != 0u; 1282 1283 if (bonding_enabed){ 1284 1285 // lookup device based on IRK 1286 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1287 int i; 1288 for (i=0; i < le_device_db_max_count(); i++){ 1289 sm_key_t irk; 1290 bd_addr_t address; 1291 int address_type = BD_ADDR_TYPE_UNKNOWN; 1292 le_device_db_info(i, &address_type, address, irk); 1293 // skip unused entries 1294 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1295 // compare IRK 1296 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1297 1298 log_info("sm: device found for IRK, updating"); 1299 le_db_index = i; 1300 break; 1301 } 1302 } else { 1303 // assert IRK is set to zero 1304 memset(setup->sm_peer_irk, 0, 16); 1305 } 1306 1307 // if not found, lookup via public address if possible 1308 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1309 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1310 int i; 1311 for (i=0; i < le_device_db_max_count(); i++){ 1312 bd_addr_t address; 1313 int address_type = BD_ADDR_TYPE_UNKNOWN; 1314 le_device_db_info(i, &address_type, address, NULL); 1315 // skip unused entries 1316 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1317 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1318 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1319 log_info("sm: device found for public address, updating"); 1320 le_db_index = i; 1321 break; 1322 } 1323 } 1324 } 1325 1326 // if not found, add to db 1327 bool new_to_le_device_db = false; 1328 if (le_db_index < 0) { 1329 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1330 new_to_le_device_db = true; 1331 } 1332 1333 if (le_db_index >= 0){ 1334 1335 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1336 if (!new_to_le_device_db){ 1337 hci_remove_le_device_db_entry_from_resolving_list(le_db_index); 1338 } 1339 hci_load_le_device_db_entry_into_resolving_list(le_db_index); 1340 #else 1341 UNUSED(new_to_le_device_db); 1342 #endif 1343 1344 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1345 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1346 1347 #ifdef ENABLE_LE_SIGNED_WRITE 1348 // store local CSRK 1349 setup->sm_le_device_index = le_db_index; 1350 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1351 log_info("sm: store local CSRK"); 1352 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1353 le_device_db_local_counter_set(le_db_index, 0); 1354 } 1355 1356 // store remote CSRK 1357 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1358 log_info("sm: store remote CSRK"); 1359 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1360 le_device_db_remote_counter_set(le_db_index, 0); 1361 } 1362 #endif 1363 // store encryption information for secure connections: LTK generated by ECDH 1364 if (setup->sm_use_secure_connections){ 1365 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1366 uint8_t zero_rand[8]; 1367 memset(zero_rand, 0, 8); 1368 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1369 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1370 } 1371 1372 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1373 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1374 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1375 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1376 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1377 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1378 1379 } 1380 } 1381 } else { 1382 log_info("Ignoring received keys, bonding not enabled"); 1383 } 1384 1385 // keep le_db_index 1386 sm_conn->sm_le_db_index = le_db_index; 1387 } 1388 1389 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1390 setup->sm_pairing_failed_reason = reason; 1391 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1392 } 1393 1394 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1395 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1396 } 1397 1398 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1399 1400 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1401 static int sm_passkey_used(stk_generation_method_t method); 1402 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1403 1404 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1405 if (setup->sm_stk_generation_method == OOB){ 1406 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1407 } else { 1408 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); 1409 } 1410 } 1411 1412 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1413 if (IS_RESPONDER(sm_conn->sm_role)){ 1414 // Responder 1415 if (setup->sm_stk_generation_method == OOB){ 1416 // generate Nb 1417 log_info("Generate Nb"); 1418 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); 1419 } else { 1420 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1421 } 1422 } else { 1423 // Initiator role 1424 switch (setup->sm_stk_generation_method){ 1425 case JUST_WORKS: 1426 sm_sc_prepare_dhkey_check(sm_conn); 1427 break; 1428 1429 case NUMERIC_COMPARISON: 1430 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1431 break; 1432 case PK_INIT_INPUT: 1433 case PK_RESP_INPUT: 1434 case PK_BOTH_INPUT: 1435 if (setup->sm_passkey_bit < 20u) { 1436 sm_sc_start_calculating_local_confirm(sm_conn); 1437 } else { 1438 sm_sc_prepare_dhkey_check(sm_conn); 1439 } 1440 break; 1441 case OOB: 1442 sm_sc_prepare_dhkey_check(sm_conn); 1443 break; 1444 } 1445 } 1446 } 1447 1448 static void sm_sc_cmac_done(uint8_t * hash){ 1449 log_info("sm_sc_cmac_done: "); 1450 log_info_hexdump(hash, 16); 1451 1452 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1453 sm_sc_oob_state = SM_SC_OOB_IDLE; 1454 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1455 return; 1456 } 1457 1458 sm_connection_t * sm_conn = sm_cmac_connection; 1459 sm_cmac_connection = NULL; 1460 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1461 link_key_type_t link_key_type; 1462 #endif 1463 1464 switch (sm_conn->sm_engine_state){ 1465 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1466 (void)memcpy(setup->sm_local_confirm, hash, 16); 1467 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1468 break; 1469 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1470 // check 1471 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1472 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1473 break; 1474 } 1475 sm_sc_state_after_receiving_random(sm_conn); 1476 break; 1477 case SM_SC_W4_CALCULATE_G2: { 1478 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1479 big_endian_store_32(setup->sm_tk, 12, vab); 1480 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1481 sm_trigger_user_response(sm_conn); 1482 break; 1483 } 1484 case SM_SC_W4_CALCULATE_F5_SALT: 1485 (void)memcpy(setup->sm_t, hash, 16); 1486 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1487 break; 1488 case SM_SC_W4_CALCULATE_F5_MACKEY: 1489 (void)memcpy(setup->sm_mackey, hash, 16); 1490 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1491 break; 1492 case SM_SC_W4_CALCULATE_F5_LTK: 1493 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1494 // Errata Service Release to the Bluetooth Specification: ESR09 1495 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1496 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1497 (void)memcpy(setup->sm_ltk, hash, 16); 1498 (void)memcpy(setup->sm_local_ltk, hash, 16); 1499 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1500 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1501 break; 1502 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1503 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1504 if (IS_RESPONDER(sm_conn->sm_role)){ 1505 // responder 1506 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1507 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1508 } else { 1509 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1510 } 1511 } else { 1512 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1513 } 1514 break; 1515 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1516 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1517 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1518 break; 1519 } 1520 if (IS_RESPONDER(sm_conn->sm_role)){ 1521 // responder 1522 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1523 } else { 1524 // initiator 1525 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1526 } 1527 break; 1528 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1529 case SM_SC_W4_CALCULATE_H6_ILK: 1530 (void)memcpy(setup->sm_t, hash, 16); 1531 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY; 1532 break; 1533 case SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY: 1534 reverse_128(hash, setup->sm_t); 1535 link_key_type = sm_conn->sm_connection_authenticated ? 1536 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1537 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1538 gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); 1539 if (IS_RESPONDER(sm_conn->sm_role)){ 1540 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1541 } else { 1542 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1543 } 1544 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 1545 sm_done_for_handle(sm_conn->sm_handle); 1546 break; 1547 #endif 1548 default: 1549 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1550 break; 1551 } 1552 sm_trigger_run(); 1553 } 1554 1555 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){ 1556 const uint16_t message_len = 65; 1557 sm_cmac_connection = sm_conn; 1558 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1559 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1560 sm_cmac_sc_buffer[64] = z; 1561 log_info("f4 key"); 1562 log_info_hexdump(x, 16); 1563 log_info("f4 message"); 1564 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1565 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1566 } 1567 1568 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1569 static const uint8_t f5_length[] = { 0x01, 0x00}; 1570 1571 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1572 1573 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1574 1575 log_info("f5_calculate_salt"); 1576 // calculate salt for f5 1577 const uint16_t message_len = 32; 1578 sm_cmac_connection = sm_conn; 1579 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1580 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1581 } 1582 1583 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){ 1584 const uint16_t message_len = 53; 1585 sm_cmac_connection = sm_conn; 1586 1587 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1588 sm_cmac_sc_buffer[0] = 0; 1589 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1590 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1591 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1592 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1593 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1594 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1595 log_info("f5 key"); 1596 log_info_hexdump(t, 16); 1597 log_info("f5 message for MacKey"); 1598 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1599 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1600 } 1601 1602 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1603 sm_key56_t bd_addr_master, bd_addr_slave; 1604 bd_addr_master[0] = setup->sm_m_addr_type; 1605 bd_addr_slave[0] = setup->sm_s_addr_type; 1606 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1607 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1608 if (IS_RESPONDER(sm_conn->sm_role)){ 1609 // responder 1610 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1611 } else { 1612 // initiator 1613 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1614 } 1615 } 1616 1617 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1618 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1619 const uint16_t message_len = 53; 1620 sm_cmac_connection = sm_conn; 1621 sm_cmac_sc_buffer[0] = 1; 1622 // 1..52 setup before 1623 log_info("f5 key"); 1624 log_info_hexdump(t, 16); 1625 log_info("f5 message for LTK"); 1626 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1627 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1628 } 1629 1630 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1631 f5_ltk(sm_conn, setup->sm_t); 1632 } 1633 1634 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){ 1635 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1636 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1637 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1638 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1639 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1640 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1641 } 1642 1643 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ 1644 const uint16_t message_len = 65; 1645 sm_cmac_connection = sm_conn; 1646 log_info("f6 key"); 1647 log_info_hexdump(w, 16); 1648 log_info("f6 message"); 1649 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1650 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1651 } 1652 1653 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1654 // - U is 256 bits 1655 // - V is 256 bits 1656 // - X is 128 bits 1657 // - Y is 128 bits 1658 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){ 1659 const uint16_t message_len = 80; 1660 sm_cmac_connection = sm_conn; 1661 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1662 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1663 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1664 log_info("g2 key"); 1665 log_info_hexdump(x, 16); 1666 log_info("g2 message"); 1667 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1668 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1669 } 1670 1671 static void g2_calculate(sm_connection_t * sm_conn) { 1672 // calc Va if numeric comparison 1673 if (IS_RESPONDER(sm_conn->sm_role)){ 1674 // responder 1675 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1676 } else { 1677 // initiator 1678 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1679 } 1680 } 1681 1682 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1683 uint8_t z = 0; 1684 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1685 // some form of passkey 1686 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1687 z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); 1688 setup->sm_passkey_bit++; 1689 } 1690 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1691 } 1692 1693 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1694 // OOB 1695 if (setup->sm_stk_generation_method == OOB){ 1696 if (IS_RESPONDER(sm_conn->sm_role)){ 1697 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1698 } else { 1699 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1700 } 1701 return; 1702 } 1703 1704 uint8_t z = 0; 1705 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1706 // some form of passkey 1707 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1708 // sm_passkey_bit was increased before sending confirm value 1709 z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); 1710 } 1711 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1712 } 1713 1714 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1715 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) ? 1 : 0); 1716 1717 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1718 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1719 return; 1720 } else { 1721 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1722 } 1723 } 1724 1725 static void sm_sc_dhkey_calculated(void * arg){ 1726 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1727 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1728 if (sm_conn == NULL) return; 1729 1730 log_info("dhkey"); 1731 log_info_hexdump(&setup->sm_dhkey[0], 32); 1732 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1733 // trigger next step 1734 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1735 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1736 } 1737 sm_trigger_run(); 1738 } 1739 1740 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1741 // calculate DHKCheck 1742 sm_key56_t bd_addr_master, bd_addr_slave; 1743 bd_addr_master[0] = setup->sm_m_addr_type; 1744 bd_addr_slave[0] = setup->sm_s_addr_type; 1745 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1746 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1747 uint8_t iocap_a[3]; 1748 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1749 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1750 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1751 uint8_t iocap_b[3]; 1752 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1753 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1754 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1755 if (IS_RESPONDER(sm_conn->sm_role)){ 1756 // responder 1757 f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1758 f6_engine(sm_conn, setup->sm_mackey); 1759 } else { 1760 // initiator 1761 f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1762 f6_engine(sm_conn, setup->sm_mackey); 1763 } 1764 } 1765 1766 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1767 // validate E = f6() 1768 sm_key56_t bd_addr_master, bd_addr_slave; 1769 bd_addr_master[0] = setup->sm_m_addr_type; 1770 bd_addr_slave[0] = setup->sm_s_addr_type; 1771 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1772 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1773 1774 uint8_t iocap_a[3]; 1775 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1776 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1777 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1778 uint8_t iocap_b[3]; 1779 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1780 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1781 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1782 if (IS_RESPONDER(sm_conn->sm_role)){ 1783 // responder 1784 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1785 f6_engine(sm_conn, setup->sm_mackey); 1786 } else { 1787 // initiator 1788 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1789 f6_engine(sm_conn, setup->sm_mackey); 1790 } 1791 } 1792 1793 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1794 1795 // 1796 // Link Key Conversion Function h6 1797 // 1798 // h6(W, keyID) = AES-CMACW(keyID) 1799 // - W is 128 bits 1800 // - keyID is 32 bits 1801 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1802 const uint16_t message_len = 4; 1803 sm_cmac_connection = sm_conn; 1804 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1805 log_info("h6 key"); 1806 log_info_hexdump(w, 16); 1807 log_info("h6 message"); 1808 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1809 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1810 } 1811 1812 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1813 // Errata Service Release to the Bluetooth Specification: ESR09 1814 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1815 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1816 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1817 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1818 } 1819 1820 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1821 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1822 } 1823 1824 #endif 1825 1826 #endif 1827 1828 // key management legacy connections: 1829 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1830 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1831 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1832 // - responder reconnects: responder uses LTK receveived from master 1833 1834 // key management secure connections: 1835 // - both devices store same LTK from ECDH key exchange. 1836 1837 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1838 static void sm_load_security_info(sm_connection_t * sm_connection){ 1839 int encryption_key_size; 1840 int authenticated; 1841 int authorized; 1842 int secure_connection; 1843 1844 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1845 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1846 &encryption_key_size, &authenticated, &authorized, &secure_connection); 1847 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); 1848 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1849 sm_connection->sm_connection_authenticated = authenticated; 1850 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1851 sm_connection->sm_connection_sc = secure_connection; 1852 } 1853 #endif 1854 1855 #ifdef ENABLE_LE_PERIPHERAL 1856 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1857 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1858 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1859 // re-establish used key encryption size 1860 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1861 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; 1862 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1863 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; 1864 // Legacy paring -> not SC 1865 sm_connection->sm_connection_sc = 0; 1866 log_info("sm: received ltk request with key size %u, authenticated %u", 1867 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1868 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1869 sm_trigger_run(); 1870 } 1871 #endif 1872 1873 // distributed key generation 1874 static bool sm_run_dpkg(void){ 1875 switch (dkg_state){ 1876 case DKG_CALC_IRK: 1877 // already busy? 1878 if (sm_aes128_state == SM_AES128_IDLE) { 1879 log_info("DKG_CALC_IRK started"); 1880 // IRK = d1(IR, 1, 0) 1881 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 1882 sm_aes128_state = SM_AES128_ACTIVE; 1883 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 1884 return true; 1885 } 1886 break; 1887 case DKG_CALC_DHK: 1888 // already busy? 1889 if (sm_aes128_state == SM_AES128_IDLE) { 1890 log_info("DKG_CALC_DHK started"); 1891 // DHK = d1(IR, 3, 0) 1892 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 1893 sm_aes128_state = SM_AES128_ACTIVE; 1894 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 1895 return true; 1896 } 1897 break; 1898 default: 1899 break; 1900 } 1901 return false; 1902 } 1903 1904 // random address updates 1905 static bool sm_run_rau(void){ 1906 switch (rau_state){ 1907 case RAU_GET_RANDOM: 1908 rau_state = RAU_W4_RANDOM; 1909 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 1910 return true; 1911 case RAU_GET_ENC: 1912 // already busy? 1913 if (sm_aes128_state == SM_AES128_IDLE) { 1914 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 1915 sm_aes128_state = SM_AES128_ACTIVE; 1916 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 1917 return true; 1918 } 1919 break; 1920 case RAU_SET_ADDRESS: 1921 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1922 rau_state = RAU_IDLE; 1923 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1924 return true; 1925 default: 1926 break; 1927 } 1928 return false; 1929 } 1930 1931 // CSRK Lookup 1932 static bool sm_run_csrk(void){ 1933 btstack_linked_list_iterator_t it; 1934 1935 // -- if csrk lookup ready, find connection that require csrk lookup 1936 if (sm_address_resolution_idle()){ 1937 hci_connections_get_iterator(&it); 1938 while(btstack_linked_list_iterator_has_next(&it)){ 1939 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1940 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1941 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1942 // and start lookup 1943 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); 1944 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1945 break; 1946 } 1947 } 1948 } 1949 1950 // -- if csrk lookup ready, resolved addresses for received addresses 1951 if (sm_address_resolution_idle()) { 1952 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1953 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1954 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1955 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1956 btstack_memory_sm_lookup_entry_free(entry); 1957 } 1958 } 1959 1960 // -- Continue with CSRK device lookup by public or resolvable private address 1961 if (!sm_address_resolution_idle()){ 1962 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 1963 while (sm_address_resolution_test < le_device_db_max_count()){ 1964 int addr_type = BD_ADDR_TYPE_UNKNOWN; 1965 bd_addr_t addr; 1966 sm_key_t irk; 1967 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 1968 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 1969 1970 // skip unused entries 1971 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 1972 sm_address_resolution_test++; 1973 continue; 1974 } 1975 1976 if ((sm_address_resolution_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 1977 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 1978 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 1979 break; 1980 } 1981 1982 // if connection type is public, it must be a different one 1983 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 1984 sm_address_resolution_test++; 1985 continue; 1986 } 1987 1988 if (sm_aes128_state == SM_AES128_ACTIVE) break; 1989 1990 log_info("LE Device Lookup: calculate AH"); 1991 log_info_key("IRK", irk); 1992 1993 (void)memcpy(sm_aes128_key, irk, 16); 1994 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 1995 sm_address_resolution_ah_calculation_active = 1; 1996 sm_aes128_state = SM_AES128_ACTIVE; 1997 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 1998 return true; 1999 } 2000 2001 if (sm_address_resolution_test >= le_device_db_max_count()){ 2002 log_info("LE Device Lookup: not found"); 2003 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2004 } 2005 } 2006 return false; 2007 } 2008 2009 // SC OOB 2010 static bool sm_run_oob(void){ 2011 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2012 switch (sm_sc_oob_state){ 2013 case SM_SC_OOB_W2_CALC_CONFIRM: 2014 if (!sm_cmac_ready()) break; 2015 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2016 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2017 return true; 2018 default: 2019 break; 2020 } 2021 #endif 2022 return false; 2023 } 2024 2025 // handle basic actions that don't requires the full context 2026 static bool sm_run_basic(void){ 2027 btstack_linked_list_iterator_t it; 2028 hci_connections_get_iterator(&it); 2029 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2030 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2031 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2032 switch(sm_connection->sm_engine_state){ 2033 // responder side 2034 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2035 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2036 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2037 return true; 2038 2039 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2040 case SM_SC_RECEIVED_LTK_REQUEST: 2041 switch (sm_connection->sm_irk_lookup_state){ 2042 case IRK_LOOKUP_FAILED: 2043 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 2044 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2045 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2046 return true; 2047 default: 2048 break; 2049 } 2050 break; 2051 #endif 2052 default: 2053 break; 2054 } 2055 } 2056 return false; 2057 } 2058 2059 static void sm_run_activate_connection(void){ 2060 // Find connections that requires setup context and make active if no other is locked 2061 btstack_linked_list_iterator_t it; 2062 hci_connections_get_iterator(&it); 2063 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2064 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2065 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2066 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2067 int done = 1; 2068 int err; 2069 UNUSED(err); 2070 2071 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2072 // assert ec key is ready 2073 if ((sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2074 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST)){ 2075 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2076 sm_ec_generate_new_key(); 2077 } 2078 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2079 continue; 2080 } 2081 } 2082 #endif 2083 2084 switch (sm_connection->sm_engine_state) { 2085 #ifdef ENABLE_LE_PERIPHERAL 2086 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2087 // send packet if possible, 2088 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2089 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2090 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2091 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2092 } else { 2093 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2094 } 2095 // don't lock sxetup context yet 2096 done = 0; 2097 break; 2098 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2099 sm_reset_setup(); 2100 sm_init_setup(sm_connection); 2101 // recover pairing request 2102 (void)memcpy(&setup->sm_m_preq, 2103 &sm_connection->sm_m_preq, 2104 sizeof(sm_pairing_packet_t)); 2105 err = sm_stk_generation_init(sm_connection); 2106 2107 #ifdef ENABLE_TESTING_SUPPORT 2108 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 2109 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2110 err = test_pairing_failure; 2111 } 2112 #endif 2113 if (err){ 2114 setup->sm_pairing_failed_reason = err; 2115 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2116 break; 2117 } 2118 sm_timeout_start(sm_connection); 2119 // generate random number first, if we need to show passkey 2120 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2121 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) sm_connection->sm_handle); 2122 break; 2123 } 2124 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2125 break; 2126 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2127 sm_reset_setup(); 2128 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2129 break; 2130 2131 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2132 case SM_SC_RECEIVED_LTK_REQUEST: 2133 switch (sm_connection->sm_irk_lookup_state){ 2134 case IRK_LOOKUP_SUCCEEDED: 2135 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2136 // start using context by loading security info 2137 sm_reset_setup(); 2138 sm_load_security_info(sm_connection); 2139 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2140 (void)memcpy(setup->sm_ltk, 2141 setup->sm_peer_ltk, 16); 2142 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2143 break; 2144 } 2145 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2146 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2147 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2148 // don't lock setup context yet 2149 return; 2150 default: 2151 // just wait until IRK lookup is completed 2152 // don't lock setup context yet 2153 done = 0; 2154 break; 2155 } 2156 break; 2157 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2158 #endif /* ENABLE_LE_PERIPHERAL */ 2159 2160 #ifdef ENABLE_LE_CENTRAL 2161 case SM_INITIATOR_PH0_HAS_LTK: 2162 sm_reset_setup(); 2163 sm_load_security_info(sm_connection); 2164 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2165 break; 2166 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2167 sm_reset_setup(); 2168 sm_init_setup(sm_connection); 2169 sm_timeout_start(sm_connection); 2170 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2171 break; 2172 #endif 2173 2174 default: 2175 done = 0; 2176 break; 2177 } 2178 if (done){ 2179 sm_active_connection_handle = sm_connection->sm_handle; 2180 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); 2181 } 2182 } 2183 } 2184 2185 static void sm_run(void){ 2186 2187 // assert that stack has already bootet 2188 if (hci_get_state() != HCI_STATE_WORKING) return; 2189 2190 // assert that we can send at least commands 2191 if (!hci_can_send_command_packet_now()) return; 2192 2193 // pause until IR/ER are ready 2194 if (sm_persistent_keys_random_active) return; 2195 2196 bool done; 2197 2198 // 2199 // non-connection related behaviour 2200 // 2201 2202 done = sm_run_dpkg(); 2203 if (done) return; 2204 2205 done = sm_run_rau(); 2206 if (done) return; 2207 2208 done = sm_run_csrk(); 2209 if (done) return; 2210 2211 done = sm_run_oob(); 2212 if (done) return; 2213 2214 // assert that we can send at least commands - cmd might have been sent by crypto engine 2215 if (!hci_can_send_command_packet_now()) return; 2216 2217 // handle basic actions that don't requires the full context 2218 done = sm_run_basic(); 2219 if (done) return; 2220 2221 // 2222 // active connection handling 2223 // -- use loop to handle next connection if lock on setup context is released 2224 2225 while (true) { 2226 2227 sm_run_activate_connection(); 2228 2229 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2230 2231 // 2232 // active connection handling 2233 // 2234 2235 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2236 if (!connection) { 2237 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2238 return; 2239 } 2240 2241 // assert that we could send a SM PDU - not needed for all of the following 2242 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2243 log_info("cannot send now, requesting can send now event"); 2244 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2245 return; 2246 } 2247 2248 // send keypress notifications 2249 if (setup->sm_keypress_notification){ 2250 int i; 2251 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2252 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2253 uint8_t action = 0; 2254 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2255 if (flags & (1u<<i)){ 2256 int clear_flag = 1; 2257 switch (i){ 2258 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2259 case SM_KEYPRESS_PASSKEY_CLEARED: 2260 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2261 default: 2262 break; 2263 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2264 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2265 num_actions--; 2266 clear_flag = num_actions == 0u; 2267 break; 2268 } 2269 if (clear_flag){ 2270 flags &= ~(1<<i); 2271 } 2272 action = i; 2273 break; 2274 } 2275 } 2276 setup->sm_keypress_notification = (num_actions << 5) | flags; 2277 2278 // send keypress notification 2279 uint8_t buffer[2]; 2280 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2281 buffer[1] = action; 2282 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2283 2284 // try 2285 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2286 return; 2287 } 2288 2289 int key_distribution_flags; 2290 UNUSED(key_distribution_flags); 2291 2292 log_info("sm_run: state %u", connection->sm_engine_state); 2293 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2294 log_info("sm_run // cannot send"); 2295 } 2296 switch (connection->sm_engine_state){ 2297 2298 // general 2299 case SM_GENERAL_SEND_PAIRING_FAILED: { 2300 uint8_t buffer[2]; 2301 buffer[0] = SM_CODE_PAIRING_FAILED; 2302 buffer[1] = setup->sm_pairing_failed_reason; 2303 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2304 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2305 sm_notify_client_status_reason(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2306 sm_done_for_handle(connection->sm_handle); 2307 break; 2308 } 2309 2310 // responding state 2311 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2312 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2313 if (!sm_cmac_ready()) break; 2314 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2315 sm_sc_calculate_local_confirm(connection); 2316 break; 2317 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2318 if (!sm_cmac_ready()) break; 2319 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2320 sm_sc_calculate_remote_confirm(connection); 2321 break; 2322 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2323 if (!sm_cmac_ready()) break; 2324 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2325 sm_sc_calculate_f6_for_dhkey_check(connection); 2326 break; 2327 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2328 if (!sm_cmac_ready()) break; 2329 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2330 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2331 break; 2332 case SM_SC_W2_CALCULATE_F5_SALT: 2333 if (!sm_cmac_ready()) break; 2334 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2335 f5_calculate_salt(connection); 2336 break; 2337 case SM_SC_W2_CALCULATE_F5_MACKEY: 2338 if (!sm_cmac_ready()) break; 2339 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2340 f5_calculate_mackey(connection); 2341 break; 2342 case SM_SC_W2_CALCULATE_F5_LTK: 2343 if (!sm_cmac_ready()) break; 2344 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2345 f5_calculate_ltk(connection); 2346 break; 2347 case SM_SC_W2_CALCULATE_G2: 2348 if (!sm_cmac_ready()) break; 2349 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2350 g2_calculate(connection); 2351 break; 2352 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2353 case SM_SC_W2_CALCULATE_H6_ILK: 2354 if (!sm_cmac_ready()) break; 2355 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_ILK; 2356 h6_calculate_ilk(connection); 2357 break; 2358 case SM_SC_W2_CALCULATE_H6_BR_EDR_LINK_KEY: 2359 if (!sm_cmac_ready()) break; 2360 connection->sm_engine_state = SM_SC_W4_CALCULATE_H6_BR_EDR_LINK_KEY; 2361 h6_calculate_br_edr_link_key(connection); 2362 break; 2363 #endif 2364 #endif 2365 2366 #ifdef ENABLE_LE_CENTRAL 2367 // initiator side 2368 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2369 sm_key_t peer_ltk_flipped; 2370 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2371 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2372 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2373 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2374 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2375 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2376 return; 2377 } 2378 2379 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2380 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2381 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2382 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2383 sm_timeout_reset(connection); 2384 break; 2385 #endif 2386 2387 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2388 2389 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2390 int trigger_user_response = 0; 2391 int trigger_start_calculating_local_confirm = 0; 2392 uint8_t buffer[65]; 2393 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2394 // 2395 reverse_256(&ec_q[0], &buffer[1]); 2396 reverse_256(&ec_q[32], &buffer[33]); 2397 2398 #ifdef ENABLE_TESTING_SUPPORT 2399 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2400 log_info("testing_support: invalidating public key"); 2401 // flip single bit of public key coordinate 2402 buffer[1] ^= 1; 2403 } 2404 #endif 2405 2406 // stk generation method 2407 // passkey entry: notify app to show passkey or to request passkey 2408 switch (setup->sm_stk_generation_method){ 2409 case JUST_WORKS: 2410 case NUMERIC_COMPARISON: 2411 if (IS_RESPONDER(connection->sm_role)){ 2412 // responder 2413 trigger_start_calculating_local_confirm = 1; 2414 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2415 } else { 2416 // initiator 2417 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2418 } 2419 break; 2420 case PK_INIT_INPUT: 2421 case PK_RESP_INPUT: 2422 case PK_BOTH_INPUT: 2423 // use random TK for display 2424 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2425 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2426 setup->sm_passkey_bit = 0; 2427 2428 if (IS_RESPONDER(connection->sm_role)){ 2429 // responder 2430 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2431 } else { 2432 // initiator 2433 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2434 } 2435 trigger_user_response = 1; 2436 break; 2437 case OOB: 2438 if (IS_RESPONDER(connection->sm_role)){ 2439 // responder 2440 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2441 } else { 2442 // initiator 2443 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2444 } 2445 break; 2446 } 2447 2448 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2449 sm_timeout_reset(connection); 2450 2451 // trigger user response and calc confirm after sending pdu 2452 if (trigger_user_response){ 2453 sm_trigger_user_response(connection); 2454 } 2455 if (trigger_start_calculating_local_confirm){ 2456 sm_sc_start_calculating_local_confirm(connection); 2457 } 2458 break; 2459 } 2460 case SM_SC_SEND_CONFIRMATION: { 2461 uint8_t buffer[17]; 2462 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2463 reverse_128(setup->sm_local_confirm, &buffer[1]); 2464 if (IS_RESPONDER(connection->sm_role)){ 2465 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2466 } else { 2467 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2468 } 2469 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2470 sm_timeout_reset(connection); 2471 break; 2472 } 2473 case SM_SC_SEND_PAIRING_RANDOM: { 2474 uint8_t buffer[17]; 2475 buffer[0] = SM_CODE_PAIRING_RANDOM; 2476 reverse_128(setup->sm_local_nonce, &buffer[1]); 2477 log_info("stk method %u, num bits %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2478 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2479 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2480 if (IS_RESPONDER(connection->sm_role)){ 2481 // responder 2482 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2483 } else { 2484 // initiator 2485 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2486 } 2487 } else { 2488 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2489 if (IS_RESPONDER(connection->sm_role)){ 2490 // responder 2491 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2492 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2493 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2494 } else { 2495 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2496 sm_sc_prepare_dhkey_check(connection); 2497 } 2498 } else { 2499 // initiator 2500 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2501 } 2502 } 2503 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2504 sm_timeout_reset(connection); 2505 break; 2506 } 2507 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2508 uint8_t buffer[17]; 2509 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2510 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2511 2512 if (IS_RESPONDER(connection->sm_role)){ 2513 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2514 } else { 2515 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2516 } 2517 2518 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2519 sm_timeout_reset(connection); 2520 break; 2521 } 2522 2523 #endif 2524 2525 #ifdef ENABLE_LE_PERIPHERAL 2526 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2527 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2528 2529 // start with initiator key dist flags 2530 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2531 2532 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2533 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2534 if (setup->sm_use_secure_connections){ 2535 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2536 } 2537 #endif 2538 // setup in response 2539 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); 2540 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); 2541 2542 // update key distribution after ENC was dropped 2543 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2544 2545 if (setup->sm_use_secure_connections){ 2546 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2547 } else { 2548 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2549 } 2550 2551 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2552 sm_timeout_reset(connection); 2553 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2554 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 2555 sm_trigger_user_response(connection); 2556 } 2557 return; 2558 #endif 2559 2560 case SM_PH2_SEND_PAIRING_RANDOM: { 2561 uint8_t buffer[17]; 2562 buffer[0] = SM_CODE_PAIRING_RANDOM; 2563 reverse_128(setup->sm_local_random, &buffer[1]); 2564 if (IS_RESPONDER(connection->sm_role)){ 2565 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2566 } else { 2567 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2568 } 2569 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2570 sm_timeout_reset(connection); 2571 break; 2572 } 2573 2574 case SM_PH2_C1_GET_ENC_A: 2575 // already busy? 2576 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2577 // calculate confirm using aes128 engine - step 1 2578 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); 2579 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2580 sm_aes128_state = SM_AES128_ACTIVE; 2581 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); 2582 break; 2583 2584 case SM_PH2_C1_GET_ENC_C: 2585 // already busy? 2586 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2587 // calculate m_confirm using aes128 engine - step 1 2588 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); 2589 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2590 sm_aes128_state = SM_AES128_ACTIVE; 2591 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); 2592 break; 2593 2594 case SM_PH2_CALC_STK: 2595 // already busy? 2596 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2597 // calculate STK 2598 if (IS_RESPONDER(connection->sm_role)){ 2599 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2600 } else { 2601 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2602 } 2603 connection->sm_engine_state = SM_PH2_W4_STK; 2604 sm_aes128_state = SM_AES128_ACTIVE; 2605 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); 2606 break; 2607 2608 case SM_PH3_Y_GET_ENC: 2609 // already busy? 2610 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2611 // PH3B2 - calculate Y from - enc 2612 2613 // dm helper (was sm_dm_r_prime) 2614 // r' = padding || r 2615 // r - 64 bit value 2616 memset(&sm_aes128_plaintext[0], 0, 8); 2617 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2618 2619 // Y = dm(DHK, Rand) 2620 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2621 sm_aes128_state = SM_AES128_ACTIVE; 2622 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); 2623 break; 2624 2625 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2626 uint8_t buffer[17]; 2627 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2628 reverse_128(setup->sm_local_confirm, &buffer[1]); 2629 if (IS_RESPONDER(connection->sm_role)){ 2630 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2631 } else { 2632 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2633 } 2634 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2635 sm_timeout_reset(connection); 2636 return; 2637 } 2638 #ifdef ENABLE_LE_PERIPHERAL 2639 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2640 sm_key_t stk_flipped; 2641 reverse_128(setup->sm_ltk, stk_flipped); 2642 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2643 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2644 return; 2645 } 2646 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2647 sm_key_t ltk_flipped; 2648 reverse_128(setup->sm_ltk, ltk_flipped); 2649 connection->sm_engine_state = SM_RESPONDER_IDLE; 2650 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2651 sm_done_for_handle(connection->sm_handle); 2652 return; 2653 } 2654 case SM_RESPONDER_PH4_Y_GET_ENC: 2655 // already busy? 2656 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2657 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2658 2659 // dm helper (was sm_dm_r_prime) 2660 // r' = padding || r 2661 // r - 64 bit value 2662 memset(&sm_aes128_plaintext[0], 0, 8); 2663 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2664 2665 // Y = dm(DHK, Rand) 2666 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 2667 sm_aes128_state = SM_AES128_ACTIVE; 2668 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); 2669 return; 2670 #endif 2671 #ifdef ENABLE_LE_CENTRAL 2672 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2673 sm_key_t stk_flipped; 2674 reverse_128(setup->sm_ltk, stk_flipped); 2675 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2676 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2677 return; 2678 } 2679 #endif 2680 2681 case SM_PH3_DISTRIBUTE_KEYS: 2682 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2683 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2684 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2685 uint8_t buffer[17]; 2686 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2687 reverse_128(setup->sm_ltk, &buffer[1]); 2688 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2689 sm_timeout_reset(connection); 2690 return; 2691 } 2692 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2693 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2694 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2695 uint8_t buffer[11]; 2696 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2697 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2698 reverse_64(setup->sm_local_rand, &buffer[3]); 2699 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2700 sm_timeout_reset(connection); 2701 return; 2702 } 2703 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2704 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2705 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2706 uint8_t buffer[17]; 2707 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2708 reverse_128(sm_persistent_irk, &buffer[1]); 2709 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2710 sm_timeout_reset(connection); 2711 return; 2712 } 2713 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2714 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2715 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2716 bd_addr_t local_address; 2717 uint8_t buffer[8]; 2718 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2719 switch (gap_random_address_get_mode()){ 2720 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2721 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2722 // public or static random 2723 gap_le_get_own_address(&buffer[1], local_address); 2724 break; 2725 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2726 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2727 // fallback to public 2728 gap_local_bd_addr(local_address); 2729 buffer[1] = 0; 2730 break; 2731 } 2732 reverse_bd_addr(local_address, &buffer[2]); 2733 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2734 sm_timeout_reset(connection); 2735 return; 2736 } 2737 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2738 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2739 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2740 2741 #ifdef ENABLE_LE_SIGNED_WRITE 2742 // hack to reproduce test runs 2743 if (test_use_fixed_local_csrk){ 2744 memset(setup->sm_local_csrk, 0xcc, 16); 2745 } 2746 2747 // store local CSRK 2748 if (setup->sm_le_device_index >= 0){ 2749 log_info("sm: store local CSRK"); 2750 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2751 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2752 } 2753 #endif 2754 2755 uint8_t buffer[17]; 2756 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2757 reverse_128(setup->sm_local_csrk, &buffer[1]); 2758 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2759 sm_timeout_reset(connection); 2760 return; 2761 } 2762 2763 // keys are sent 2764 if (IS_RESPONDER(connection->sm_role)){ 2765 // slave -> receive master keys if any 2766 if (sm_key_distribution_all_received(connection)){ 2767 sm_key_distribution_handle_all_received(connection); 2768 connection->sm_engine_state = SM_RESPONDER_IDLE; 2769 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2770 sm_done_for_handle(connection->sm_handle); 2771 } else { 2772 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2773 } 2774 } else { 2775 sm_master_pairing_success(connection); 2776 } 2777 break; 2778 2779 default: 2780 break; 2781 } 2782 2783 // check again if active connection was released 2784 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2785 } 2786 } 2787 2788 // sm_aes128_state stays active 2789 static void sm_handle_encryption_result_enc_a(void *arg){ 2790 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2791 sm_aes128_state = SM_AES128_IDLE; 2792 2793 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2794 if (connection == NULL) return; 2795 2796 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2797 sm_aes128_state = SM_AES128_ACTIVE; 2798 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); 2799 } 2800 2801 static void sm_handle_encryption_result_enc_b(void *arg){ 2802 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2803 sm_aes128_state = SM_AES128_IDLE; 2804 2805 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2806 if (connection == NULL) return; 2807 2808 log_info_key("c1!", setup->sm_local_confirm); 2809 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2810 sm_trigger_run(); 2811 } 2812 2813 // sm_aes128_state stays active 2814 static void sm_handle_encryption_result_enc_c(void *arg){ 2815 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2816 sm_aes128_state = SM_AES128_IDLE; 2817 2818 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2819 if (connection == NULL) return; 2820 2821 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2822 sm_aes128_state = SM_AES128_ACTIVE; 2823 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); 2824 } 2825 2826 static void sm_handle_encryption_result_enc_d(void * arg){ 2827 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2828 sm_aes128_state = SM_AES128_IDLE; 2829 2830 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2831 if (connection == NULL) return; 2832 2833 log_info_key("c1!", sm_aes128_ciphertext); 2834 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 2835 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2836 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2837 sm_trigger_run(); 2838 return; 2839 } 2840 if (IS_RESPONDER(connection->sm_role)){ 2841 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2842 sm_trigger_run(); 2843 } else { 2844 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2845 sm_aes128_state = SM_AES128_ACTIVE; 2846 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); 2847 } 2848 } 2849 2850 static void sm_handle_encryption_result_enc_stk(void *arg){ 2851 sm_aes128_state = SM_AES128_IDLE; 2852 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2853 2854 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2855 if (connection == NULL) return; 2856 2857 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2858 log_info_key("stk", setup->sm_ltk); 2859 if (IS_RESPONDER(connection->sm_role)){ 2860 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2861 } else { 2862 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2863 } 2864 sm_trigger_run(); 2865 } 2866 2867 // sm_aes128_state stays active 2868 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 2869 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2870 sm_aes128_state = SM_AES128_IDLE; 2871 2872 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2873 if (connection == NULL) return; 2874 2875 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2876 log_info_hex16("y", setup->sm_local_y); 2877 // PH3B3 - calculate EDIV 2878 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2879 log_info_hex16("ediv", setup->sm_local_ediv); 2880 // PH3B4 - calculate LTK - enc 2881 // LTK = d1(ER, DIV, 0)) 2882 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2883 sm_aes128_state = SM_AES128_ACTIVE; 2884 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); 2885 } 2886 2887 #ifdef ENABLE_LE_PERIPHERAL 2888 // sm_aes128_state stays active 2889 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 2890 sm_aes128_state = SM_AES128_IDLE; 2891 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2892 2893 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2894 if (connection == NULL) return; 2895 2896 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2897 log_info_hex16("y", setup->sm_local_y); 2898 2899 // PH3B3 - calculate DIV 2900 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2901 log_info_hex16("ediv", setup->sm_local_ediv); 2902 // PH3B4 - calculate LTK - enc 2903 // LTK = d1(ER, DIV, 0)) 2904 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2905 sm_aes128_state = SM_AES128_ACTIVE; 2906 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); 2907 } 2908 #endif 2909 2910 // sm_aes128_state stays active 2911 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 2912 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2913 sm_aes128_state = SM_AES128_IDLE; 2914 2915 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2916 if (connection == NULL) return; 2917 2918 log_info_key("ltk", setup->sm_ltk); 2919 // calc CSRK next 2920 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 2921 sm_aes128_state = SM_AES128_ACTIVE; 2922 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); 2923 } 2924 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 2925 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2926 // requirements to derive link key from LE: 2927 // - use secure connections 2928 if (setup->sm_use_secure_connections == 0) return false; 2929 // - bonding needs to be enabled: 2930 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; 2931 if (!bonding_enabled) return false; 2932 // - need identity address 2933 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0); 2934 if (!have_identity_address_info) return false; 2935 // - 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) 2936 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 2937 // If SC is authenticated, we consider it safe to overwrite a stored key. 2938 // 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. 2939 uint8_t link_key[16]; 2940 link_key_type_t link_key_type; 2941 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 2942 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type) != 0; 2943 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 2944 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 2945 return false; 2946 } 2947 // get started (all of the above are true) 2948 return true; 2949 #else 2950 return false; 2951 #endif 2952 } 2953 2954 static void sm_handle_encryption_result_enc_csrk(void *arg){ 2955 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2956 sm_aes128_state = SM_AES128_IDLE; 2957 2958 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2959 if (connection == NULL) return; 2960 2961 sm_aes128_state = SM_AES128_IDLE; 2962 log_info_key("csrk", setup->sm_local_csrk); 2963 if (setup->sm_key_distribution_send_set){ 2964 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 2965 } else { 2966 // no keys to send, just continue 2967 if (IS_RESPONDER(connection->sm_role)){ 2968 // slave -> receive master keys 2969 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2970 } else { 2971 if (sm_ctkd_from_le(connection)){ 2972 connection->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 2973 } else { 2974 sm_master_pairing_success(connection); 2975 } 2976 } 2977 } 2978 sm_trigger_run(); 2979 } 2980 2981 #ifdef ENABLE_LE_PERIPHERAL 2982 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 2983 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2984 sm_aes128_state = SM_AES128_IDLE; 2985 2986 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2987 if (connection == NULL) return; 2988 2989 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2990 log_info_key("ltk", setup->sm_ltk); 2991 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2992 sm_trigger_run(); 2993 } 2994 #endif 2995 2996 static void sm_handle_encryption_result_address_resolution(void *arg){ 2997 UNUSED(arg); 2998 sm_aes128_state = SM_AES128_IDLE; 2999 3000 sm_address_resolution_ah_calculation_active = 0; 3001 // compare calulated address against connecting device 3002 uint8_t * hash = &sm_aes128_ciphertext[13]; 3003 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3004 log_info("LE Device Lookup: matched resolvable private address"); 3005 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 3006 sm_trigger_run(); 3007 return; 3008 } 3009 // no match, try next 3010 sm_address_resolution_test++; 3011 sm_trigger_run(); 3012 } 3013 3014 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3015 UNUSED(arg); 3016 sm_aes128_state = SM_AES128_IDLE; 3017 3018 log_info_key("irk", sm_persistent_irk); 3019 dkg_state = DKG_CALC_DHK; 3020 sm_trigger_run(); 3021 } 3022 3023 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3024 UNUSED(arg); 3025 sm_aes128_state = SM_AES128_IDLE; 3026 3027 log_info_key("dhk", sm_persistent_dhk); 3028 dkg_state = DKG_READY; 3029 sm_trigger_run(); 3030 } 3031 3032 static void sm_handle_encryption_result_rau(void *arg){ 3033 UNUSED(arg); 3034 sm_aes128_state = SM_AES128_IDLE; 3035 3036 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3037 rau_state = RAU_SET_ADDRESS; 3038 sm_trigger_run(); 3039 } 3040 3041 static void sm_handle_random_result_rau(void * arg){ 3042 UNUSED(arg); 3043 // non-resolvable vs. resolvable 3044 switch (gap_random_adress_type){ 3045 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3046 // resolvable: use random as prand and calc address hash 3047 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3048 sm_random_address[0u] &= 0x3fu; 3049 sm_random_address[0u] |= 0x40u; 3050 rau_state = RAU_GET_ENC; 3051 break; 3052 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3053 default: 3054 // "The two most significant bits of the address shall be equal to ‘0’"" 3055 sm_random_address[0u] &= 0x3fu; 3056 rau_state = RAU_SET_ADDRESS; 3057 break; 3058 } 3059 sm_trigger_run(); 3060 } 3061 3062 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3063 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 3064 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3065 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3066 if (connection == NULL) return; 3067 3068 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3069 sm_trigger_run(); 3070 } 3071 3072 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3073 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3074 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3075 if (connection == NULL) return; 3076 3077 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3078 sm_trigger_run(); 3079 } 3080 #endif 3081 3082 static void sm_handle_random_result_ph2_random(void * arg){ 3083 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3084 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3085 if (connection == NULL) return; 3086 3087 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3088 sm_trigger_run(); 3089 } 3090 3091 static void sm_handle_random_result_ph2_tk(void * arg){ 3092 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3093 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3094 if (connection == NULL) return; 3095 3096 sm_reset_tk(); 3097 uint32_t tk; 3098 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 3099 // map random to 0-999999 without speding much cycles on a modulus operation 3100 tk = little_endian_read_32(sm_random_data,0); 3101 tk = tk & 0xfffff; // 1048575 3102 if (tk >= 999999u){ 3103 tk = tk - 999999u; 3104 } 3105 } else { 3106 // override with pre-defined passkey 3107 tk = sm_fixed_passkey_in_display_role; 3108 } 3109 big_endian_store_32(setup->sm_tk, 12, tk); 3110 if (IS_RESPONDER(connection->sm_role)){ 3111 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3112 } else { 3113 if (setup->sm_use_secure_connections){ 3114 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3115 } else { 3116 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3117 sm_trigger_user_response(connection); 3118 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3119 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3120 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); 3121 } 3122 } 3123 } 3124 sm_trigger_run(); 3125 } 3126 3127 static void sm_handle_random_result_ph3_div(void * arg){ 3128 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3129 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3130 if (connection == NULL) return; 3131 3132 // use 16 bit from random value as div 3133 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3134 log_info_hex16("div", setup->sm_local_div); 3135 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3136 sm_trigger_run(); 3137 } 3138 3139 static void sm_handle_random_result_ph3_random(void * arg){ 3140 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3141 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3142 if (connection == NULL) return; 3143 3144 reverse_64(sm_random_data, setup->sm_local_rand); 3145 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3146 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3147 // no db for authenticated flag hack: store flag in bit 4 of LSB 3148 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3149 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3150 } 3151 static void sm_validate_er_ir(void){ 3152 // warn about default ER/IR 3153 int warning = 0; 3154 if (sm_ir_is_default()){ 3155 warning = 1; 3156 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3157 } 3158 if (sm_er_is_default()){ 3159 warning = 1; 3160 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3161 } 3162 if (warning) { 3163 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3164 } 3165 } 3166 3167 static void sm_handle_random_result_ir(void *arg){ 3168 sm_persistent_keys_random_active = 0; 3169 if (arg){ 3170 // key generated, store in tlv 3171 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3172 log_info("Generated IR key. Store in TLV status: %d", status); 3173 } 3174 log_info_key("IR", sm_persistent_ir); 3175 dkg_state = DKG_CALC_IRK; 3176 3177 if (test_use_fixed_local_irk){ 3178 log_info_key("IRK", sm_persistent_irk); 3179 dkg_state = DKG_CALC_DHK; 3180 } 3181 3182 sm_trigger_run(); 3183 } 3184 3185 static void sm_handle_random_result_er(void *arg){ 3186 sm_persistent_keys_random_active = 0; 3187 if (arg){ 3188 // key generated, store in tlv 3189 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3190 log_info("Generated ER key. Store in TLV status: %d", status); 3191 } 3192 log_info_key("ER", sm_persistent_er); 3193 3194 // try load ir 3195 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3196 if (key_size == 16){ 3197 // ok, let's continue 3198 log_info("IR from TLV"); 3199 sm_handle_random_result_ir( NULL ); 3200 } else { 3201 // invalid, generate new random one 3202 sm_persistent_keys_random_active = 1; 3203 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3204 } 3205 } 3206 3207 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3208 3209 UNUSED(channel); // ok: there is no channel 3210 UNUSED(size); // ok: fixed format HCI events 3211 3212 sm_connection_t * sm_conn; 3213 hci_con_handle_t con_handle; 3214 3215 switch (packet_type) { 3216 3217 case HCI_EVENT_PACKET: 3218 switch (hci_event_packet_get_type(packet)) { 3219 3220 case BTSTACK_EVENT_STATE: 3221 // bt stack activated, get started 3222 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3223 log_info("HCI Working!"); 3224 3225 // setup IR/ER with TLV 3226 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3227 if (sm_tlv_impl){ 3228 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3229 if (key_size == 16){ 3230 // ok, let's continue 3231 log_info("ER from TLV"); 3232 sm_handle_random_result_er( NULL ); 3233 } else { 3234 // invalid, generate random one 3235 sm_persistent_keys_random_active = 1; 3236 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3237 } 3238 } else { 3239 sm_validate_er_ir(); 3240 dkg_state = DKG_CALC_IRK; 3241 3242 if (test_use_fixed_local_irk){ 3243 log_info_key("IRK", sm_persistent_irk); 3244 dkg_state = DKG_CALC_DHK; 3245 } 3246 } 3247 3248 // restart random address updates after power cycle 3249 gap_random_address_set_mode(gap_random_adress_type); 3250 } 3251 break; 3252 3253 case HCI_EVENT_LE_META: 3254 switch (packet[2]) { 3255 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3256 3257 log_info("sm: connected"); 3258 3259 if (packet[3]) return; // connection failed 3260 3261 con_handle = little_endian_read_16(packet, 4); 3262 sm_conn = sm_get_connection_for_handle(con_handle); 3263 if (!sm_conn) break; 3264 3265 sm_conn->sm_handle = con_handle; 3266 sm_conn->sm_role = packet[6]; 3267 sm_conn->sm_peer_addr_type = packet[7]; 3268 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3269 3270 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3271 3272 // reset security properties 3273 sm_conn->sm_connection_encrypted = 0; 3274 sm_conn->sm_connection_authenticated = 0; 3275 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3276 sm_conn->sm_le_db_index = -1; 3277 3278 // prepare CSRK lookup (does not involve setup) 3279 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3280 3281 // just connected -> everything else happens in sm_run() 3282 if (IS_RESPONDER(sm_conn->sm_role)){ 3283 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3284 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3285 if (sm_slave_request_security) { 3286 // request security if requested by app 3287 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3288 } else { 3289 // otherwise, wait for pairing request 3290 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3291 } 3292 } 3293 break; 3294 } else { 3295 // master 3296 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3297 } 3298 break; 3299 3300 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3301 con_handle = little_endian_read_16(packet, 3); 3302 sm_conn = sm_get_connection_for_handle(con_handle); 3303 if (!sm_conn) break; 3304 3305 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3306 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3307 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3308 break; 3309 } 3310 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3311 // PH2 SEND LTK as we need to exchange keys in PH3 3312 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3313 break; 3314 } 3315 3316 // store rand and ediv 3317 reverse_64(&packet[5], sm_conn->sm_local_rand); 3318 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3319 3320 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3321 // potentially stored LTK is from the master 3322 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 3323 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3324 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3325 break; 3326 } 3327 // additionally check if remote is in LE Device DB if requested 3328 switch(sm_conn->sm_irk_lookup_state){ 3329 case IRK_LOOKUP_FAILED: 3330 log_info("LTK Request: device not in device db"); 3331 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3332 break; 3333 case IRK_LOOKUP_SUCCEEDED: 3334 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3335 break; 3336 default: 3337 // wait for irk look doen 3338 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3339 break; 3340 } 3341 break; 3342 } 3343 3344 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3345 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3346 #else 3347 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3348 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3349 #endif 3350 break; 3351 3352 default: 3353 break; 3354 } 3355 break; 3356 3357 case HCI_EVENT_ENCRYPTION_CHANGE: 3358 con_handle = little_endian_read_16(packet, 3); 3359 sm_conn = sm_get_connection_for_handle(con_handle); 3360 if (!sm_conn) break; 3361 3362 sm_conn->sm_connection_encrypted = packet[5]; 3363 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3364 sm_conn->sm_actual_encryption_key_size); 3365 log_info("event handler, state %u", sm_conn->sm_engine_state); 3366 3367 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3368 if (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED){ 3369 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3370 // notify client, if pairing was requested before 3371 if (sm_conn->sm_pairing_requested){ 3372 sm_conn->sm_pairing_requested = 0; 3373 if (sm_conn->sm_connection_encrypted){ 3374 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3375 } else { 3376 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, 0); 3377 } 3378 } 3379 sm_done_for_handle(sm_conn->sm_handle); 3380 break; 3381 } 3382 3383 if (!sm_conn->sm_connection_encrypted) break; 3384 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3385 3386 // continue pairing 3387 switch (sm_conn->sm_engine_state){ 3388 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3389 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3390 sm_done_for_handle(sm_conn->sm_handle); 3391 break; 3392 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3393 if (IS_RESPONDER(sm_conn->sm_role)){ 3394 // slave 3395 if (setup->sm_use_secure_connections){ 3396 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3397 } else { 3398 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); 3399 } 3400 } else { 3401 // master 3402 if (sm_key_distribution_all_received(sm_conn)){ 3403 // skip receiving keys as there are none 3404 sm_key_distribution_handle_all_received(sm_conn); 3405 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); 3406 } else { 3407 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3408 } 3409 } 3410 break; 3411 default: 3412 break; 3413 } 3414 break; 3415 3416 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3417 con_handle = little_endian_read_16(packet, 3); 3418 sm_conn = sm_get_connection_for_handle(con_handle); 3419 if (!sm_conn) break; 3420 3421 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3422 log_info("event handler, state %u", sm_conn->sm_engine_state); 3423 // continue if part of initial pairing 3424 switch (sm_conn->sm_engine_state){ 3425 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3426 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3427 sm_done_for_handle(sm_conn->sm_handle); 3428 break; 3429 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3430 if (IS_RESPONDER(sm_conn->sm_role)){ 3431 // slave 3432 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); 3433 } else { 3434 // master 3435 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3436 } 3437 break; 3438 default: 3439 break; 3440 } 3441 break; 3442 3443 3444 case HCI_EVENT_DISCONNECTION_COMPLETE: 3445 con_handle = little_endian_read_16(packet, 3); 3446 sm_done_for_handle(con_handle); 3447 sm_conn = sm_get_connection_for_handle(con_handle); 3448 if (!sm_conn) break; 3449 3450 // delete stored bonding on disconnect with authentication failure in ph0 3451 if ((sm_conn->sm_role == 0u) 3452 && (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED) 3453 && (packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE)){ 3454 le_device_db_remove(sm_conn->sm_le_db_index); 3455 } 3456 3457 // pairing failed, if it was ongoing 3458 switch (sm_conn->sm_engine_state){ 3459 case SM_GENERAL_IDLE: 3460 case SM_INITIATOR_CONNECTED: 3461 case SM_RESPONDER_IDLE: 3462 break; 3463 default: 3464 sm_notify_client_status_reason(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3465 break; 3466 } 3467 3468 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3469 sm_conn->sm_handle = 0; 3470 break; 3471 3472 case HCI_EVENT_COMMAND_COMPLETE: 3473 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3474 // set local addr for le device db 3475 bd_addr_t addr; 3476 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3477 le_device_db_set_local_bd_addr(addr); 3478 } 3479 break; 3480 default: 3481 break; 3482 } 3483 break; 3484 default: 3485 break; 3486 } 3487 3488 sm_run(); 3489 } 3490 3491 static inline int sm_calc_actual_encryption_key_size(int other){ 3492 if (other < sm_min_encryption_key_size) return 0; 3493 if (other < sm_max_encryption_key_size) return other; 3494 return sm_max_encryption_key_size; 3495 } 3496 3497 3498 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3499 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3500 switch (method){ 3501 case JUST_WORKS: 3502 case NUMERIC_COMPARISON: 3503 return 1; 3504 default: 3505 return 0; 3506 } 3507 } 3508 // responder 3509 3510 static int sm_passkey_used(stk_generation_method_t method){ 3511 switch (method){ 3512 case PK_RESP_INPUT: 3513 return 1; 3514 default: 3515 return 0; 3516 } 3517 } 3518 3519 static int sm_passkey_entry(stk_generation_method_t method){ 3520 switch (method){ 3521 case PK_RESP_INPUT: 3522 case PK_INIT_INPUT: 3523 case PK_BOTH_INPUT: 3524 return 1; 3525 default: 3526 return 0; 3527 } 3528 } 3529 3530 #endif 3531 3532 /** 3533 * @return ok 3534 */ 3535 static int sm_validate_stk_generation_method(void){ 3536 // check if STK generation method is acceptable by client 3537 switch (setup->sm_stk_generation_method){ 3538 case JUST_WORKS: 3539 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 3540 case PK_RESP_INPUT: 3541 case PK_INIT_INPUT: 3542 case PK_BOTH_INPUT: 3543 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 3544 case OOB: 3545 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 3546 case NUMERIC_COMPARISON: 3547 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 3548 default: 3549 return 0; 3550 } 3551 } 3552 3553 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3554 3555 // size of complete sm_pdu used to validate input 3556 static const uint8_t sm_pdu_size[] = { 3557 0, // 0x00 invalid opcode 3558 7, // 0x01 pairing request 3559 7, // 0x02 pairing response 3560 17, // 0x03 pairing confirm 3561 17, // 0x04 pairing random 3562 2, // 0x05 pairing failed 3563 17, // 0x06 encryption information 3564 11, // 0x07 master identification 3565 17, // 0x08 identification information 3566 8, // 0x09 identify address information 3567 17, // 0x0a signing information 3568 2, // 0x0b security request 3569 65, // 0x0c pairing public key 3570 17, // 0x0d pairing dhk check 3571 2, // 0x0e keypress notification 3572 }; 3573 3574 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 3575 sm_run(); 3576 } 3577 3578 if (packet_type != SM_DATA_PACKET) return; 3579 if (size == 0u) return; 3580 3581 uint8_t sm_pdu_code = packet[0]; 3582 3583 // validate pdu size 3584 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3585 if (sm_pdu_size[sm_pdu_code] != size) return; 3586 3587 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3588 if (!sm_conn) return; 3589 3590 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3591 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3592 sm_done_for_handle(con_handle); 3593 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3594 return; 3595 } 3596 3597 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3598 3599 int err; 3600 UNUSED(err); 3601 3602 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3603 uint8_t buffer[5]; 3604 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3605 buffer[1] = 3; 3606 little_endian_store_16(buffer, 2, con_handle); 3607 buffer[4] = packet[1]; 3608 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3609 return; 3610 } 3611 3612 switch (sm_conn->sm_engine_state){ 3613 3614 // a sm timeout requries a new physical connection 3615 case SM_GENERAL_TIMEOUT: 3616 return; 3617 3618 #ifdef ENABLE_LE_CENTRAL 3619 3620 // Initiator 3621 case SM_INITIATOR_CONNECTED: 3622 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3623 sm_pdu_received_in_wrong_state(sm_conn); 3624 break; 3625 } 3626 3627 // IRK complete? 3628 int have_ltk; 3629 uint8_t ltk[16]; 3630 switch (sm_conn->sm_irk_lookup_state){ 3631 case IRK_LOOKUP_FAILED: 3632 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3633 break; 3634 case IRK_LOOKUP_SUCCEEDED: 3635 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 3636 have_ltk = !sm_is_null_key(ltk); 3637 log_info("central: security request - have_ltk %u", have_ltk); 3638 if (have_ltk){ 3639 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3640 } else { 3641 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3642 } 3643 break; 3644 default: 3645 break; 3646 } 3647 3648 // otherwise, store security request 3649 sm_conn->sm_security_request_received = 1; 3650 break; 3651 3652 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3653 // Core 5, Vol 3, Part H, 2.4.6: 3654 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3655 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3656 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3657 log_info("Ignoring Security Request"); 3658 break; 3659 } 3660 3661 // all other pdus are incorrect 3662 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3663 sm_pdu_received_in_wrong_state(sm_conn); 3664 break; 3665 } 3666 3667 // store pairing request 3668 (void)memcpy(&setup->sm_s_pres, packet, 3669 sizeof(sm_pairing_packet_t)); 3670 err = sm_stk_generation_init(sm_conn); 3671 3672 #ifdef ENABLE_TESTING_SUPPORT 3673 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3674 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3675 err = test_pairing_failure; 3676 } 3677 #endif 3678 3679 if (err){ 3680 setup->sm_pairing_failed_reason = err; 3681 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3682 break; 3683 } 3684 3685 // generate random number first, if we need to show passkey 3686 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3687 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); 3688 break; 3689 } 3690 3691 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3692 if (setup->sm_use_secure_connections){ 3693 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3694 if (setup->sm_stk_generation_method == JUST_WORKS){ 3695 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3696 sm_trigger_user_response(sm_conn); 3697 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3698 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3699 } 3700 } else { 3701 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3702 } 3703 break; 3704 } 3705 #endif 3706 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3707 sm_trigger_user_response(sm_conn); 3708 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3709 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3710 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); 3711 } 3712 break; 3713 3714 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3715 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3716 sm_pdu_received_in_wrong_state(sm_conn); 3717 break; 3718 } 3719 3720 // store s_confirm 3721 reverse_128(&packet[1], setup->sm_peer_confirm); 3722 3723 #ifdef ENABLE_TESTING_SUPPORT 3724 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3725 log_info("testing_support: reset confirm value"); 3726 memset(setup->sm_peer_confirm, 0, 16); 3727 } 3728 #endif 3729 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3730 break; 3731 3732 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3733 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3734 sm_pdu_received_in_wrong_state(sm_conn); 3735 break;; 3736 } 3737 3738 // received random value 3739 reverse_128(&packet[1], setup->sm_peer_random); 3740 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3741 break; 3742 #endif 3743 3744 #ifdef ENABLE_LE_PERIPHERAL 3745 // Responder 3746 case SM_RESPONDER_IDLE: 3747 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3748 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3749 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3750 sm_pdu_received_in_wrong_state(sm_conn); 3751 break;; 3752 } 3753 3754 // store pairing request 3755 (void)memcpy(&sm_conn->sm_m_preq, packet, 3756 sizeof(sm_pairing_packet_t)); 3757 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3758 break; 3759 #endif 3760 3761 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3762 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3763 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3764 sm_pdu_received_in_wrong_state(sm_conn); 3765 break; 3766 } 3767 3768 // store public key for DH Key calculation 3769 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3770 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3771 3772 // validate public key 3773 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 3774 if (err){ 3775 log_error("sm: peer public key invalid %x", err); 3776 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 3777 break; 3778 } 3779 3780 // start calculating dhkey 3781 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); 3782 3783 3784 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3785 if (IS_RESPONDER(sm_conn->sm_role)){ 3786 // responder 3787 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3788 } else { 3789 // initiator 3790 // stk generation method 3791 // passkey entry: notify app to show passkey or to request passkey 3792 switch (setup->sm_stk_generation_method){ 3793 case JUST_WORKS: 3794 case NUMERIC_COMPARISON: 3795 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3796 break; 3797 case PK_RESP_INPUT: 3798 sm_sc_start_calculating_local_confirm(sm_conn); 3799 break; 3800 case PK_INIT_INPUT: 3801 case PK_BOTH_INPUT: 3802 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3803 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3804 break; 3805 } 3806 sm_sc_start_calculating_local_confirm(sm_conn); 3807 break; 3808 case OOB: 3809 // generate Nx 3810 log_info("Generate Na"); 3811 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); 3812 break; 3813 } 3814 } 3815 break; 3816 3817 case SM_SC_W4_CONFIRMATION: 3818 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3819 sm_pdu_received_in_wrong_state(sm_conn); 3820 break; 3821 } 3822 // received confirm value 3823 reverse_128(&packet[1], setup->sm_peer_confirm); 3824 3825 #ifdef ENABLE_TESTING_SUPPORT 3826 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3827 log_info("testing_support: reset confirm value"); 3828 memset(setup->sm_peer_confirm, 0, 16); 3829 } 3830 #endif 3831 if (IS_RESPONDER(sm_conn->sm_role)){ 3832 // responder 3833 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3834 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3835 // still waiting for passkey 3836 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3837 break; 3838 } 3839 } 3840 sm_sc_start_calculating_local_confirm(sm_conn); 3841 } else { 3842 // initiator 3843 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3844 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); 3845 } else { 3846 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3847 } 3848 } 3849 break; 3850 3851 case SM_SC_W4_PAIRING_RANDOM: 3852 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3853 sm_pdu_received_in_wrong_state(sm_conn); 3854 break; 3855 } 3856 3857 // received random value 3858 reverse_128(&packet[1], setup->sm_peer_nonce); 3859 3860 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3861 // only check for JUST WORK/NC in initiator role OR passkey entry 3862 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 3863 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 3864 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 3865 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 3866 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 3867 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3868 break; 3869 } 3870 3871 // OOB 3872 if (setup->sm_stk_generation_method == OOB){ 3873 3874 // setup local random, set to zero if remote did not receive our data 3875 log_info("Received nonce, setup local random ra/rb for dhkey check"); 3876 if (IS_RESPONDER(sm_conn->sm_role)){ 3877 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u){ 3878 log_info("Reset rb as A does not have OOB data"); 3879 memset(setup->sm_rb, 0, 16); 3880 } else { 3881 (void)memcpy(setup->sm_rb, sm_sc_oob_random, 16); 3882 log_info("Use stored rb"); 3883 log_info_hexdump(setup->sm_rb, 16); 3884 } 3885 } else { 3886 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 3887 log_info("Reset ra as B does not have OOB data"); 3888 memset(setup->sm_ra, 0, 16); 3889 } else { 3890 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 3891 log_info("Use stored ra"); 3892 log_info_hexdump(setup->sm_ra, 16); 3893 } 3894 } 3895 3896 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 3897 if (setup->sm_have_oob_data){ 3898 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3899 break; 3900 } 3901 } 3902 3903 // TODO: we only get here for Responder role with JW/NC 3904 sm_sc_state_after_receiving_random(sm_conn); 3905 break; 3906 3907 case SM_SC_W2_CALCULATE_G2: 3908 case SM_SC_W4_CALCULATE_G2: 3909 case SM_SC_W4_CALCULATE_DHKEY: 3910 case SM_SC_W2_CALCULATE_F5_SALT: 3911 case SM_SC_W4_CALCULATE_F5_SALT: 3912 case SM_SC_W2_CALCULATE_F5_MACKEY: 3913 case SM_SC_W4_CALCULATE_F5_MACKEY: 3914 case SM_SC_W2_CALCULATE_F5_LTK: 3915 case SM_SC_W4_CALCULATE_F5_LTK: 3916 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3917 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3918 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3919 case SM_SC_W4_USER_RESPONSE: 3920 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 3921 sm_pdu_received_in_wrong_state(sm_conn); 3922 break; 3923 } 3924 // store DHKey Check 3925 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3926 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3927 3928 // have we been only waiting for dhkey check command? 3929 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3930 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3931 } 3932 break; 3933 #endif 3934 3935 #ifdef ENABLE_LE_PERIPHERAL 3936 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3937 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3938 sm_pdu_received_in_wrong_state(sm_conn); 3939 break; 3940 } 3941 3942 // received confirm value 3943 reverse_128(&packet[1], setup->sm_peer_confirm); 3944 3945 #ifdef ENABLE_TESTING_SUPPORT 3946 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3947 log_info("testing_support: reset confirm value"); 3948 memset(setup->sm_peer_confirm, 0, 16); 3949 } 3950 #endif 3951 // notify client to hide shown passkey 3952 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3953 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3954 } 3955 3956 // handle user cancel pairing? 3957 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3958 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 3959 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3960 break; 3961 } 3962 3963 // wait for user action? 3964 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 3965 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3966 break; 3967 } 3968 3969 // calculate and send local_confirm 3970 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); 3971 break; 3972 3973 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 3974 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3975 sm_pdu_received_in_wrong_state(sm_conn); 3976 break;; 3977 } 3978 3979 // received random value 3980 reverse_128(&packet[1], setup->sm_peer_random); 3981 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3982 break; 3983 #endif 3984 3985 case SM_PH3_RECEIVE_KEYS: 3986 switch(sm_pdu_code){ 3987 case SM_CODE_ENCRYPTION_INFORMATION: 3988 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 3989 reverse_128(&packet[1], setup->sm_peer_ltk); 3990 break; 3991 3992 case SM_CODE_MASTER_IDENTIFICATION: 3993 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 3994 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 3995 reverse_64(&packet[3], setup->sm_peer_rand); 3996 break; 3997 3998 case SM_CODE_IDENTITY_INFORMATION: 3999 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4000 reverse_128(&packet[1], setup->sm_peer_irk); 4001 break; 4002 4003 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4004 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4005 setup->sm_peer_addr_type = packet[1]; 4006 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4007 break; 4008 4009 case SM_CODE_SIGNING_INFORMATION: 4010 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4011 reverse_128(&packet[1], setup->sm_peer_csrk); 4012 break; 4013 default: 4014 // Unexpected PDU 4015 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4016 break; 4017 } 4018 // done with key distribution? 4019 if (sm_key_distribution_all_received(sm_conn)){ 4020 4021 sm_key_distribution_handle_all_received(sm_conn); 4022 4023 if (IS_RESPONDER(sm_conn->sm_role)){ 4024 if (sm_ctkd_from_le(sm_conn)){ 4025 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_H6_ILK; 4026 } else { 4027 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 4028 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 4029 sm_done_for_handle(sm_conn->sm_handle); 4030 } 4031 } else { 4032 if (setup->sm_use_secure_connections){ 4033 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4034 } else { 4035 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); 4036 } 4037 } 4038 } 4039 break; 4040 default: 4041 // Unexpected PDU 4042 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4043 break; 4044 } 4045 4046 // try to send next pdu 4047 sm_trigger_run(); 4048 } 4049 4050 // Security Manager Client API 4051 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 4052 sm_get_oob_data = get_oob_data_callback; 4053 } 4054 4055 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)){ 4056 sm_get_sc_oob_data = get_sc_oob_data_callback; 4057 } 4058 4059 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4060 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4061 } 4062 4063 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 4064 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 4065 } 4066 4067 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 4068 sm_min_encryption_key_size = min_size; 4069 sm_max_encryption_key_size = max_size; 4070 } 4071 4072 void sm_set_authentication_requirements(uint8_t auth_req){ 4073 #ifndef ENABLE_LE_SECURE_CONNECTIONS 4074 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 4075 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 4076 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 4077 } 4078 #endif 4079 sm_auth_req = auth_req; 4080 } 4081 4082 void sm_set_io_capabilities(io_capability_t io_capability){ 4083 sm_io_capabilities = io_capability; 4084 } 4085 4086 #ifdef ENABLE_LE_PERIPHERAL 4087 void sm_set_request_security(int enable){ 4088 sm_slave_request_security = enable; 4089 } 4090 #endif 4091 4092 void sm_set_er(sm_key_t er){ 4093 (void)memcpy(sm_persistent_er, er, 16); 4094 } 4095 4096 void sm_set_ir(sm_key_t ir){ 4097 (void)memcpy(sm_persistent_ir, ir, 16); 4098 } 4099 4100 // Testing support only 4101 void sm_test_set_irk(sm_key_t irk){ 4102 (void)memcpy(sm_persistent_irk, irk, 16); 4103 dkg_state = DKG_CALC_DHK; 4104 test_use_fixed_local_irk = true; 4105 } 4106 4107 void sm_test_use_fixed_local_csrk(void){ 4108 test_use_fixed_local_csrk = true; 4109 } 4110 4111 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4112 static void sm_ec_generated(void * arg){ 4113 UNUSED(arg); 4114 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4115 // trigger pairing if pending for ec key 4116 sm_trigger_run(); 4117 } 4118 static void sm_ec_generate_new_key(void){ 4119 log_info("sm: generate new ec key"); 4120 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 4121 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 4122 } 4123 #endif 4124 4125 #ifdef ENABLE_TESTING_SUPPORT 4126 void sm_test_set_pairing_failure(int reason){ 4127 test_pairing_failure = reason; 4128 } 4129 #endif 4130 4131 void sm_init(void){ 4132 // set default ER and IR values (should be unique - set by app or sm later using TLV) 4133 sm_er_ir_set_default(); 4134 4135 // defaults 4136 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4137 | SM_STK_GENERATION_METHOD_OOB 4138 | SM_STK_GENERATION_METHOD_PASSKEY 4139 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4140 4141 sm_max_encryption_key_size = 16; 4142 sm_min_encryption_key_size = 7; 4143 4144 sm_fixed_passkey_in_display_role = 0xffffffff; 4145 sm_reconstruct_ltk_without_le_device_db_entry = 1; 4146 4147 #ifdef USE_CMAC_ENGINE 4148 sm_cmac_active = 0; 4149 #endif 4150 dkg_state = DKG_W4_WORKING; 4151 rau_state = RAU_IDLE; 4152 sm_aes128_state = SM_AES128_IDLE; 4153 sm_address_resolution_test = -1; // no private address to resolve yet 4154 sm_address_resolution_ah_calculation_active = 0; 4155 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4156 sm_address_resolution_general_queue = NULL; 4157 4158 gap_random_adress_update_period = 15 * 60 * 1000L; 4159 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4160 4161 test_use_fixed_local_csrk = false; 4162 4163 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 4164 4165 // register for HCI Events from HCI 4166 hci_event_callback_registration.callback = &sm_event_packet_handler; 4167 hci_add_event_handler(&hci_event_callback_registration); 4168 4169 // 4170 btstack_crypto_init(); 4171 4172 // init le_device_db 4173 le_device_db_init(); 4174 4175 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4176 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4177 4178 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4179 sm_ec_generate_new_key(); 4180 #endif 4181 } 4182 4183 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4184 sm_fixed_passkey_in_display_role = passkey; 4185 } 4186 4187 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4188 sm_reconstruct_ltk_without_le_device_db_entry = allow; 4189 } 4190 4191 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4192 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4193 if (!hci_con) return NULL; 4194 return &hci_con->sm_connection; 4195 } 4196 4197 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 4198 switch (sm_conn->sm_engine_state){ 4199 case SM_GENERAL_IDLE: 4200 case SM_RESPONDER_IDLE: 4201 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4202 sm_trigger_run(); 4203 break; 4204 default: 4205 break; 4206 } 4207 } 4208 4209 /** 4210 * @brief Trigger Security Request 4211 */ 4212 void sm_send_security_request(hci_con_handle_t con_handle){ 4213 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4214 if (!sm_conn) return; 4215 sm_send_security_request_for_connection(sm_conn); 4216 } 4217 4218 // request pairing 4219 void sm_request_pairing(hci_con_handle_t con_handle){ 4220 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4221 if (!sm_conn) return; // wrong connection 4222 4223 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4224 if (IS_RESPONDER(sm_conn->sm_role)){ 4225 sm_send_security_request_for_connection(sm_conn); 4226 } else { 4227 // used as a trigger to start central/master/initiator security procedures 4228 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 4229 uint8_t ltk[16]; 4230 bool have_ltk; 4231 switch (sm_conn->sm_irk_lookup_state){ 4232 case IRK_LOOKUP_SUCCEEDED: 4233 #ifndef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 4234 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4235 have_ltk = !sm_is_null_key(ltk); 4236 log_info("have ltk %u", have_ltk); 4237 if (have_ltk){ 4238 sm_conn->sm_pairing_requested = 1; 4239 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 4240 break; 4241 } 4242 #endif 4243 /* fall through */ 4244 4245 case IRK_LOOKUP_FAILED: 4246 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4247 break; 4248 default: 4249 log_info("irk lookup pending"); 4250 sm_conn->sm_pairing_requested = 1; 4251 break; 4252 } 4253 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 4254 sm_conn->sm_pairing_requested = 1; 4255 } 4256 } 4257 sm_trigger_run(); 4258 } 4259 4260 // called by client app on authorization request 4261 void sm_authorization_decline(hci_con_handle_t con_handle){ 4262 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4263 if (!sm_conn) return; // wrong connection 4264 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4265 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4266 } 4267 4268 void sm_authorization_grant(hci_con_handle_t con_handle){ 4269 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4270 if (!sm_conn) return; // wrong connection 4271 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4272 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4273 } 4274 4275 // GAP Bonding API 4276 4277 void sm_bonding_decline(hci_con_handle_t con_handle){ 4278 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4279 if (!sm_conn) return; // wrong connection 4280 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4281 log_info("decline, state %u", sm_conn->sm_engine_state); 4282 switch(sm_conn->sm_engine_state){ 4283 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4284 case SM_SC_W4_USER_RESPONSE: 4285 case SM_SC_W4_CONFIRMATION: 4286 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4287 #endif 4288 case SM_PH1_W4_USER_RESPONSE: 4289 switch (setup->sm_stk_generation_method){ 4290 case PK_RESP_INPUT: 4291 case PK_INIT_INPUT: 4292 case PK_BOTH_INPUT: 4293 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4294 break; 4295 case NUMERIC_COMPARISON: 4296 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4297 break; 4298 case JUST_WORKS: 4299 case OOB: 4300 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4301 break; 4302 } 4303 break; 4304 default: 4305 break; 4306 } 4307 sm_trigger_run(); 4308 } 4309 4310 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4311 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4312 if (!sm_conn) return; // wrong connection 4313 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4314 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4315 if (setup->sm_use_secure_connections){ 4316 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4317 } else { 4318 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); 4319 } 4320 } 4321 4322 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4323 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4324 sm_sc_prepare_dhkey_check(sm_conn); 4325 } 4326 #endif 4327 4328 sm_trigger_run(); 4329 } 4330 4331 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4332 // for now, it's the same 4333 sm_just_works_confirm(con_handle); 4334 } 4335 4336 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4337 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4338 if (!sm_conn) return; // wrong connection 4339 sm_reset_tk(); 4340 big_endian_store_32(setup->sm_tk, 12, passkey); 4341 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4342 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4343 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); 4344 } 4345 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4346 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 4347 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 4348 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4349 sm_sc_start_calculating_local_confirm(sm_conn); 4350 } 4351 #endif 4352 sm_trigger_run(); 4353 } 4354 4355 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4356 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4357 if (!sm_conn) return; // wrong connection 4358 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4359 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4360 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 4361 switch (action){ 4362 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4363 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4364 flags |= (1u << action); 4365 break; 4366 case SM_KEYPRESS_PASSKEY_CLEARED: 4367 // clear counter, keypress & erased flags + set passkey cleared 4368 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 4369 break; 4370 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4371 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4372 // erase actions queued 4373 num_actions--; 4374 if (num_actions == 0u){ 4375 // clear counter, keypress & erased flags 4376 flags &= 0x19u; 4377 } 4378 break; 4379 } 4380 num_actions++; 4381 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4382 break; 4383 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4384 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4385 // enter actions queued 4386 num_actions--; 4387 if (num_actions == 0u){ 4388 // clear counter, keypress & erased flags 4389 flags &= 0x19u; 4390 } 4391 break; 4392 } 4393 num_actions++; 4394 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4395 break; 4396 default: 4397 break; 4398 } 4399 setup->sm_keypress_notification = (num_actions << 5) | flags; 4400 sm_trigger_run(); 4401 } 4402 4403 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4404 static void sm_handle_random_result_oob(void * arg){ 4405 UNUSED(arg); 4406 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4407 sm_trigger_run(); 4408 } 4409 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4410 4411 static btstack_crypto_random_t sm_crypto_random_oob_request; 4412 4413 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4414 sm_sc_oob_callback = callback; 4415 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4416 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4417 return 0; 4418 } 4419 #endif 4420 4421 /** 4422 * @brief Get Identity Resolving state 4423 * @param con_handle 4424 * @return irk_lookup_state_t 4425 */ 4426 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 4427 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4428 if (!sm_conn) return IRK_LOOKUP_IDLE; 4429 return sm_conn->sm_irk_lookup_state; 4430 } 4431 4432 /** 4433 * @brief Identify device in LE Device DB 4434 * @param handle 4435 * @returns index from le_device_db or -1 if not found/identified 4436 */ 4437 int sm_le_device_index(hci_con_handle_t con_handle ){ 4438 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4439 if (!sm_conn) return -1; 4440 return sm_conn->sm_le_db_index; 4441 } 4442 4443 static int gap_random_address_type_requires_updates(void){ 4444 switch (gap_random_adress_type){ 4445 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4446 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4447 return 0; 4448 default: 4449 return 1; 4450 } 4451 } 4452 4453 static uint8_t own_address_type(void){ 4454 switch (gap_random_adress_type){ 4455 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4456 return BD_ADDR_TYPE_LE_PUBLIC; 4457 default: 4458 return BD_ADDR_TYPE_LE_RANDOM; 4459 } 4460 } 4461 4462 // GAP LE API 4463 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4464 gap_random_address_update_stop(); 4465 gap_random_adress_type = random_address_type; 4466 hci_le_set_own_address_type(own_address_type()); 4467 if (!gap_random_address_type_requires_updates()) return; 4468 gap_random_address_update_start(); 4469 gap_random_address_trigger(); 4470 } 4471 4472 gap_random_address_type_t gap_random_address_get_mode(void){ 4473 return gap_random_adress_type; 4474 } 4475 4476 void gap_random_address_set_update_period(int period_ms){ 4477 gap_random_adress_update_period = period_ms; 4478 if (!gap_random_address_type_requires_updates()) return; 4479 gap_random_address_update_stop(); 4480 gap_random_address_update_start(); 4481 } 4482 4483 void gap_random_address_set(const bd_addr_t addr){ 4484 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4485 (void)memcpy(sm_random_address, addr, 6); 4486 rau_state = RAU_SET_ADDRESS; 4487 sm_trigger_run(); 4488 } 4489 4490 #ifdef ENABLE_LE_PERIPHERAL 4491 /* 4492 * @brief Set Advertisement Paramters 4493 * @param adv_int_min 4494 * @param adv_int_max 4495 * @param adv_type 4496 * @param direct_address_type 4497 * @param direct_address 4498 * @param channel_map 4499 * @param filter_policy 4500 * 4501 * @note own_address_type is used from gap_random_address_set_mode 4502 */ 4503 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4504 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4505 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4506 direct_address_typ, direct_address, channel_map, filter_policy); 4507 } 4508 #endif 4509 4510 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4511 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4512 // wrong connection 4513 if (!sm_conn) return 0; 4514 // already encrypted 4515 if (sm_conn->sm_connection_encrypted) return 0; 4516 // only central can re-encrypt 4517 if (sm_conn->sm_role == HCI_ROLE_SLAVE) return 0; 4518 // irk status? 4519 switch(sm_conn->sm_irk_lookup_state){ 4520 case IRK_LOOKUP_FAILED: 4521 // done, cannot setup encryption 4522 return 0; 4523 case IRK_LOOKUP_SUCCEEDED: 4524 break; 4525 default: 4526 // IR Lookup pending 4527 return 1; 4528 } 4529 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset 4530 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4531 } 4532 4533 void sm_set_secure_connections_only_mode(bool enable){ 4534 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4535 sm_sc_only_mode = enable; 4536 #else 4537 // SC Only mode not possible without support for SC 4538 btstack_assert(enable == false); 4539 #endif 4540 } 4541 4542 const uint8_t * gap_get_persistent_irk(void){ 4543 return sm_persistent_irk; 4544 } 4545