1 /* 2 * Copyright (C) 2014 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 #define BTSTACK_FILE__ "sm.c" 39 40 #include <string.h> 41 #include <inttypes.h> 42 43 #include "ble/le_device_db.h" 44 #include "ble/core.h" 45 #include "ble/sm.h" 46 #include "bluetooth_company_id.h" 47 #include "btstack_bool.h" 48 #include "btstack_crypto.h" 49 #include "btstack_debug.h" 50 #include "btstack_event.h" 51 #include "btstack_linked_list.h" 52 #include "btstack_memory.h" 53 #include "btstack_tlv.h" 54 #include "gap.h" 55 #include "hci.h" 56 #include "hci_dump.h" 57 #include "l2cap.h" 58 59 #if !defined(ENABLE_LE_PERIPHERAL) && !defined(ENABLE_LE_CENTRAL) 60 #error "LE Security Manager used, but neither ENABLE_LE_PERIPHERAL nor ENABLE_LE_CENTRAL defined. Please add at least one to btstack_config.h." 61 #endif 62 63 #if defined(ENABLE_CROSS_TRANSPORT_KEY_DERIVATION) && (!defined(ENABLE_CLASSIC) || !defined(ENABLE_LE_SECURE_CONNECTIONS)) 64 #error "Cross Transport Key Derivation requires support for LE Secure Connections and BR/EDR (Classic)" 65 #endif 66 67 // assert SM Public Key can be sent/received 68 #ifdef ENABLE_LE_SECURE_CONNECTIONS 69 #if HCI_ACL_PAYLOAD_SIZE < 69 70 #error "HCI_ACL_PAYLOAD_SIZE must be at least 69 bytes when using LE Secure Conection. Please increase HCI_ACL_PAYLOAD_SIZE or disable ENABLE_LE_SECURE_CONNECTIONS" 71 #endif 72 #endif 73 74 #if defined(ENABLE_LE_PERIPHERAL) && defined(ENABLE_LE_CENTRAL) 75 #define IS_RESPONDER(role) (role) 76 #else 77 #ifdef ENABLE_LE_CENTRAL 78 // only central - never responder (avoid 'unused variable' warnings) 79 #define IS_RESPONDER(role) (0 && role) 80 #else 81 // only peripheral - always responder (avoid 'unused variable' warnings) 82 #define IS_RESPONDER(role) (1 || role) 83 #endif 84 #endif 85 86 #if defined(ENABLE_LE_SIGNED_WRITE) || defined(ENABLE_LE_SECURE_CONNECTIONS) 87 #define USE_CMAC_ENGINE 88 #endif 89 90 91 #define BTSTACK_TAG32(A,B,C,D) (((A) << 24) | ((B) << 16) | ((C) << 8) | (D)) 92 93 // 94 // SM internal types and globals 95 // 96 97 typedef enum { 98 DKG_W4_WORKING, 99 DKG_CALC_IRK, 100 DKG_CALC_DHK, 101 DKG_READY 102 } derived_key_generation_t; 103 104 typedef enum { 105 RAU_IDLE, 106 RAU_GET_RANDOM, 107 RAU_W4_RANDOM, 108 RAU_GET_ENC, 109 RAU_W4_ENC, 110 RAU_SET_ADDRESS, 111 } random_address_update_t; 112 113 typedef enum { 114 CMAC_IDLE, 115 CMAC_CALC_SUBKEYS, 116 CMAC_W4_SUBKEYS, 117 CMAC_CALC_MI, 118 CMAC_W4_MI, 119 CMAC_CALC_MLAST, 120 CMAC_W4_MLAST 121 } cmac_state_t; 122 123 typedef enum { 124 JUST_WORKS, 125 PK_RESP_INPUT, // Initiator displays PK, responder inputs PK 126 PK_INIT_INPUT, // Responder displays PK, initiator inputs PK 127 PK_BOTH_INPUT, // Only input on both, both input PK 128 NUMERIC_COMPARISON, // Only numerical compparison (yes/no) on on both sides 129 OOB // OOB available on one (SC) or both sides (legacy) 130 } stk_generation_method_t; 131 132 typedef enum { 133 SM_USER_RESPONSE_IDLE, 134 SM_USER_RESPONSE_PENDING, 135 SM_USER_RESPONSE_CONFIRM, 136 SM_USER_RESPONSE_PASSKEY, 137 SM_USER_RESPONSE_DECLINE 138 } sm_user_response_t; 139 140 typedef enum { 141 SM_AES128_IDLE, 142 SM_AES128_ACTIVE 143 } sm_aes128_state_t; 144 145 typedef enum { 146 ADDRESS_RESOLUTION_IDLE, 147 ADDRESS_RESOLUTION_GENERAL, 148 ADDRESS_RESOLUTION_FOR_CONNECTION, 149 } address_resolution_mode_t; 150 151 typedef enum { 152 ADDRESS_RESOLUTION_SUCCEEDED, 153 ADDRESS_RESOLUTION_FAILED, 154 } address_resolution_event_t; 155 156 typedef enum { 157 EC_KEY_GENERATION_IDLE, 158 EC_KEY_GENERATION_ACTIVE, 159 EC_KEY_GENERATION_DONE, 160 } ec_key_generation_state_t; 161 162 typedef enum { 163 SM_STATE_VAR_DHKEY_NEEDED = 1 << 0, 164 SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1, 165 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2, 166 } sm_state_var_t; 167 168 typedef enum { 169 SM_SC_OOB_IDLE, 170 SM_SC_OOB_W4_RANDOM, 171 SM_SC_OOB_W2_CALC_CONFIRM, 172 SM_SC_OOB_W4_CONFIRM, 173 } sm_sc_oob_state_t; 174 175 typedef uint8_t sm_key24_t[3]; 176 typedef uint8_t sm_key56_t[7]; 177 typedef uint8_t sm_key256_t[32]; 178 179 // 180 // GLOBAL DATA 181 // 182 183 static bool test_use_fixed_local_csrk; 184 static bool test_use_fixed_local_irk; 185 186 #ifdef ENABLE_TESTING_SUPPORT 187 static uint8_t test_pairing_failure; 188 #endif 189 190 // configuration 191 static uint8_t sm_accepted_stk_generation_methods; 192 static uint8_t sm_max_encryption_key_size; 193 static uint8_t sm_min_encryption_key_size; 194 static uint8_t sm_auth_req = 0; 195 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 196 static uint8_t sm_slave_request_security; 197 static uint32_t sm_fixed_passkey_in_display_role; 198 static uint8_t sm_reconstruct_ltk_without_le_device_db_entry; 199 200 #ifdef ENABLE_LE_SECURE_CONNECTIONS 201 static bool sm_sc_only_mode; 202 static uint8_t sm_sc_oob_random[16]; 203 static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); 204 static sm_sc_oob_state_t sm_sc_oob_state; 205 #endif 206 207 208 static uint8_t sm_persistent_keys_random_active; 209 static const btstack_tlv_t * sm_tlv_impl; 210 static void * sm_tlv_context; 211 212 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 213 static sm_key_t sm_persistent_er; 214 static sm_key_t sm_persistent_ir; 215 216 // derived from sm_persistent_ir 217 static sm_key_t sm_persistent_dhk; 218 static sm_key_t sm_persistent_irk; 219 static derived_key_generation_t dkg_state; 220 221 // derived from sm_persistent_er 222 // .. 223 224 // random address update 225 static random_address_update_t rau_state; 226 static bd_addr_t sm_random_address; 227 228 #ifdef USE_CMAC_ENGINE 229 // CMAC Calculation: General 230 static btstack_crypto_aes128_cmac_t sm_cmac_request; 231 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 232 static uint8_t sm_cmac_active; 233 static uint8_t sm_cmac_hash[16]; 234 #endif 235 236 // CMAC for ATT Signed Writes 237 #ifdef ENABLE_LE_SIGNED_WRITE 238 static uint16_t sm_cmac_signed_write_message_len; 239 static uint8_t sm_cmac_signed_write_header[3]; 240 static const uint8_t * sm_cmac_signed_write_message; 241 static uint8_t sm_cmac_signed_write_sign_counter[4]; 242 #endif 243 244 // CMAC for Secure Connection functions 245 #ifdef ENABLE_LE_SECURE_CONNECTIONS 246 static sm_connection_t * sm_cmac_connection; 247 static uint8_t sm_cmac_sc_buffer[80]; 248 #endif 249 250 // resolvable private address lookup / CSRK calculation 251 static int sm_address_resolution_test; 252 static int sm_address_resolution_ah_calculation_active; 253 static uint8_t sm_address_resolution_addr_type; 254 static bd_addr_t sm_address_resolution_address; 255 static void * sm_address_resolution_context; 256 static address_resolution_mode_t sm_address_resolution_mode; 257 static btstack_linked_list_t sm_address_resolution_general_queue; 258 259 // aes128 crypto engine. 260 static sm_aes128_state_t sm_aes128_state; 261 262 // crypto 263 static btstack_crypto_random_t sm_crypto_random_request; 264 static btstack_crypto_aes128_t sm_crypto_aes128_request; 265 #ifdef ENABLE_LE_SECURE_CONNECTIONS 266 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 267 #endif 268 269 // temp storage for random data 270 static uint8_t sm_random_data[8]; 271 static uint8_t sm_aes128_key[16]; 272 static uint8_t sm_aes128_plaintext[16]; 273 static uint8_t sm_aes128_ciphertext[16]; 274 275 // to receive hci events 276 static btstack_packet_callback_registration_t hci_event_callback_registration; 277 278 /* to dispatch sm event */ 279 static btstack_linked_list_t sm_event_handlers; 280 281 /* to schedule calls to sm_run */ 282 static btstack_timer_source_t sm_run_timer; 283 284 // LE Secure Connections 285 #ifdef ENABLE_LE_SECURE_CONNECTIONS 286 static ec_key_generation_state_t ec_key_generation_state; 287 static uint8_t ec_q[64]; 288 #endif 289 290 // 291 // Volume 3, Part H, Chapter 24 292 // "Security shall be initiated by the Security Manager in the device in the master role. 293 // The device in the slave role shall be the responding device." 294 // -> master := initiator, slave := responder 295 // 296 297 // data needed for security setup 298 typedef struct sm_setup_context { 299 300 btstack_timer_source_t sm_timeout; 301 302 // used in all phases 303 uint8_t sm_pairing_failed_reason; 304 305 // user response, (Phase 1 and/or 2) 306 uint8_t sm_user_response; 307 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 308 309 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 310 uint8_t sm_key_distribution_send_set; 311 uint8_t sm_key_distribution_sent_set; 312 uint8_t sm_key_distribution_received_set; 313 314 // Phase 2 (Pairing over SMP) 315 stk_generation_method_t sm_stk_generation_method; 316 sm_key_t sm_tk; 317 uint8_t sm_have_oob_data; 318 uint8_t sm_use_secure_connections; 319 320 sm_key_t sm_c1_t3_value; // c1 calculation 321 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 322 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 323 sm_key_t sm_local_random; 324 sm_key_t sm_local_confirm; 325 sm_key_t sm_peer_random; 326 sm_key_t sm_peer_confirm; 327 uint8_t sm_m_addr_type; // address and type can be removed 328 uint8_t sm_s_addr_type; // '' 329 bd_addr_t sm_m_address; // '' 330 bd_addr_t sm_s_address; // '' 331 sm_key_t sm_ltk; 332 333 uint8_t sm_state_vars; 334 #ifdef ENABLE_LE_SECURE_CONNECTIONS 335 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 336 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 337 sm_key_t sm_local_nonce; // might be combined with sm_local_random 338 uint8_t sm_dhkey[32]; 339 sm_key_t sm_peer_dhkey_check; 340 sm_key_t sm_local_dhkey_check; 341 sm_key_t sm_ra; 342 sm_key_t sm_rb; 343 sm_key_t sm_t; // used for f5 and h6 344 sm_key_t sm_mackey; 345 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 346 #endif 347 348 // Phase 3 349 350 // key distribution, we generate 351 uint16_t sm_local_y; 352 uint16_t sm_local_div; 353 uint16_t sm_local_ediv; 354 uint8_t sm_local_rand[8]; 355 sm_key_t sm_local_ltk; 356 sm_key_t sm_local_csrk; 357 sm_key_t sm_local_irk; 358 // sm_local_address/addr_type not needed 359 360 // key distribution, received from peer 361 uint16_t sm_peer_y; 362 uint16_t sm_peer_div; 363 uint16_t sm_peer_ediv; 364 uint8_t sm_peer_rand[8]; 365 sm_key_t sm_peer_ltk; 366 sm_key_t sm_peer_irk; 367 sm_key_t sm_peer_csrk; 368 uint8_t sm_peer_addr_type; 369 bd_addr_t sm_peer_address; 370 #ifdef ENABLE_LE_SIGNED_WRITE 371 int sm_le_device_index; 372 #endif 373 374 } 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 static void sm_notify_client_reencryption_started(sm_connection_t * sm_conn){ 749 // fetch addr and addr type from db, only called for valid entries 750 int identity_addr_type; 751 bd_addr_t identity_addr; 752 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 753 754 sm_notify_client_base(SM_EVENT_REENCRYPTION_STARTED, sm_conn->sm_handle, identity_addr_type, identity_addr); uint8_t event[4]; 755 } 756 757 static void sm_notify_client_reencryption_complete(sm_connection_t * sm_conn, uint8_t status){ 758 // fetch addr and addr type from db, only called for valid entries 759 int identity_addr_type; 760 bd_addr_t identity_addr; 761 le_device_db_info(sm_conn->sm_le_db_index, &identity_addr_type, identity_addr, NULL); 762 763 sm_notify_client_status(SM_EVENT_REENCRYPTION_COMPLETE, sm_conn->sm_handle, identity_addr_type, identity_addr, status); 764 } 765 766 // decide on stk generation based on 767 // - pairing request 768 // - io capabilities 769 // - OOB data availability 770 static void sm_setup_tk(void){ 771 772 // horizontal: initiator capabilities 773 // vertial: responder capabilities 774 static const stk_generation_method_t stk_generation_method [5] [5] = { 775 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 776 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 777 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 778 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 779 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 780 }; 781 782 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 783 #ifdef ENABLE_LE_SECURE_CONNECTIONS 784 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 785 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 786 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 787 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 788 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 789 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 790 }; 791 #endif 792 793 // default: just works 794 setup->sm_stk_generation_method = JUST_WORKS; 795 796 #ifdef ENABLE_LE_SECURE_CONNECTIONS 797 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 798 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 799 & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; 800 #else 801 setup->sm_use_secure_connections = 0; 802 #endif 803 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 804 805 806 // decide if OOB will be used based on SC vs. Legacy and oob flags 807 int use_oob = 0; 808 if (setup->sm_use_secure_connections){ 809 // In LE Secure Connections pairing, the out of band method is used if at least 810 // one device has the peer device's out of band authentication data available. 811 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 812 } else { 813 // In LE legacy pairing, the out of band method is used if both the devices have 814 // the other device's out of band authentication data available. 815 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 816 } 817 if (use_oob){ 818 log_info("SM: have OOB data"); 819 log_info_key("OOB", setup->sm_tk); 820 setup->sm_stk_generation_method = OOB; 821 return; 822 } 823 824 // If both devices have not set the MITM option in the Authentication Requirements 825 // Flags, then the IO capabilities shall be ignored and the Just Works association 826 // model shall be used. 827 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) 828 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ 829 log_info("SM: MITM not required by both -> JUST WORKS"); 830 return; 831 } 832 833 // Reset TK as it has been setup in sm_init_setup 834 sm_reset_tk(); 835 836 // Also use just works if unknown io capabilites 837 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)){ 838 return; 839 } 840 841 // Otherwise the IO capabilities of the devices shall be used to determine the 842 // pairing method as defined in Table 2.4. 843 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 844 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 845 846 #ifdef ENABLE_LE_SECURE_CONNECTIONS 847 // table not define by default 848 if (setup->sm_use_secure_connections){ 849 generation_method = stk_generation_method_with_secure_connection; 850 } 851 #endif 852 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)]; 853 854 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 855 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); 856 } 857 858 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 859 int flags = 0; 860 if (key_set & SM_KEYDIST_ENC_KEY){ 861 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 862 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 863 } 864 if (key_set & SM_KEYDIST_ID_KEY){ 865 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 866 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 867 } 868 if (key_set & SM_KEYDIST_SIGN){ 869 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 870 } 871 return flags; 872 } 873 874 static void sm_setup_key_distribution(uint8_t key_set){ 875 setup->sm_key_distribution_received_set = 0; 876 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 877 setup->sm_key_distribution_sent_set = 0; 878 #ifdef ENABLE_LE_SIGNED_WRITE 879 setup->sm_le_device_index = -1; 880 #endif 881 } 882 883 // CSRK Key Lookup 884 885 886 static int sm_address_resolution_idle(void){ 887 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 888 } 889 890 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){ 891 (void)memcpy(sm_address_resolution_address, addr, 6); 892 sm_address_resolution_addr_type = addr_type; 893 sm_address_resolution_test = 0; 894 sm_address_resolution_mode = mode; 895 sm_address_resolution_context = context; 896 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 897 } 898 899 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 900 // check if already in list 901 btstack_linked_list_iterator_t it; 902 sm_lookup_entry_t * entry; 903 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 904 while(btstack_linked_list_iterator_has_next(&it)){ 905 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 906 if (entry->address_type != address_type) continue; 907 if (memcmp(entry->address, address, 6)) continue; 908 // already in list 909 return BTSTACK_BUSY; 910 } 911 entry = btstack_memory_sm_lookup_entry_get(); 912 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 913 entry->address_type = (bd_addr_type_t) address_type; 914 (void)memcpy(entry->address, address, 6); 915 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 916 sm_trigger_run(); 917 return 0; 918 } 919 920 // CMAC calculation using AES Engineq 921 #ifdef USE_CMAC_ENGINE 922 923 static void sm_cmac_done_trampoline(void * arg){ 924 UNUSED(arg); 925 sm_cmac_active = 0; 926 (*sm_cmac_done_callback)(sm_cmac_hash); 927 sm_trigger_run(); 928 } 929 930 int sm_cmac_ready(void){ 931 return sm_cmac_active == 0u; 932 } 933 #endif 934 935 #ifdef ENABLE_LE_SECURE_CONNECTIONS 936 // generic cmac calculation 937 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)){ 938 sm_cmac_active = 1; 939 sm_cmac_done_callback = done_callback; 940 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 941 } 942 #endif 943 944 // cmac for ATT Message signing 945 #ifdef ENABLE_LE_SIGNED_WRITE 946 947 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)){ 948 sm_cmac_active = 1; 949 sm_cmac_done_callback = done_callback; 950 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 951 } 952 953 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 954 if (offset >= sm_cmac_signed_write_message_len) { 955 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 956 return 0; 957 } 958 959 offset = sm_cmac_signed_write_message_len - 1 - offset; 960 961 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 962 if (offset < 3){ 963 return sm_cmac_signed_write_header[offset]; 964 } 965 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 966 if (offset < actual_message_len_incl_header){ 967 return sm_cmac_signed_write_message[offset - 3]; 968 } 969 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 970 } 971 972 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)){ 973 // ATT Message Signing 974 sm_cmac_signed_write_header[0] = opcode; 975 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 976 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 977 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 978 sm_cmac_signed_write_message = message; 979 sm_cmac_signed_write_message_len = total_message_len; 980 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 981 } 982 #endif 983 984 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 985 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 986 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 987 switch (setup->sm_stk_generation_method){ 988 case PK_RESP_INPUT: 989 if (IS_RESPONDER(sm_conn->sm_role)){ 990 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 991 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 992 } else { 993 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)); 994 } 995 break; 996 case PK_INIT_INPUT: 997 if (IS_RESPONDER(sm_conn->sm_role)){ 998 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)); 999 } else { 1000 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1001 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1002 } 1003 break; 1004 case PK_BOTH_INPUT: 1005 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1006 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1007 break; 1008 case NUMERIC_COMPARISON: 1009 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1010 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)); 1011 break; 1012 case JUST_WORKS: 1013 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 1014 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 1015 break; 1016 case OOB: 1017 // client already provided OOB data, let's skip notification. 1018 break; 1019 default: 1020 btstack_assert(false); 1021 break; 1022 } 1023 } 1024 1025 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1026 int recv_flags; 1027 if (IS_RESPONDER(sm_conn->sm_role)){ 1028 // slave / responder 1029 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1030 } else { 1031 // master / initiator 1032 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1033 } 1034 1035 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1036 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1037 if (setup->sm_use_secure_connections){ 1038 recv_flags &= ~(SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION | SM_KEYDIST_FLAG_MASTER_IDENTIFICATION); 1039 } 1040 #endif 1041 1042 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1043 return (setup->sm_key_distribution_received_set & recv_flags) == recv_flags; 1044 } 1045 1046 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1047 if (sm_active_connection_handle == con_handle){ 1048 sm_timeout_stop(); 1049 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1050 log_info("sm: connection 0x%x released setup context", con_handle); 1051 1052 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1053 // generate new ec key after each pairing (that used it) 1054 if (setup->sm_use_secure_connections){ 1055 sm_ec_generate_new_key(); 1056 } 1057 #endif 1058 } 1059 } 1060 1061 static void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done 1062 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1063 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 1064 sm_done_for_handle(connection->sm_handle); 1065 } 1066 1067 static int sm_key_distribution_flags_for_auth_req(void){ 1068 1069 int flags = SM_KEYDIST_ID_KEY; 1070 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1071 // encryption and signing information only if bonding requested 1072 flags |= SM_KEYDIST_ENC_KEY; 1073 #ifdef ENABLE_LE_SIGNED_WRITE 1074 flags |= SM_KEYDIST_SIGN; 1075 #endif 1076 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1077 // LinkKey for CTKD requires SC 1078 if (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 1079 flags |= SM_KEYDIST_LINK_KEY; 1080 } 1081 #endif 1082 } 1083 return flags; 1084 } 1085 1086 static void sm_reset_setup(void){ 1087 // fill in sm setup 1088 setup->sm_state_vars = 0; 1089 setup->sm_keypress_notification = 0; 1090 sm_reset_tk(); 1091 } 1092 1093 static void sm_init_setup(sm_connection_t * sm_conn){ 1094 1095 // fill in sm setup 1096 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1097 (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1098 1099 // query client for Legacy Pairing OOB data 1100 setup->sm_have_oob_data = 0; 1101 if (sm_get_oob_data) { 1102 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1103 } 1104 1105 // if available and SC supported, also ask for SC OOB Data 1106 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1107 memset(setup->sm_ra, 0, 16); 1108 memset(setup->sm_rb, 0, 16); 1109 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1110 if (sm_get_sc_oob_data){ 1111 if (IS_RESPONDER(sm_conn->sm_role)){ 1112 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1113 sm_conn->sm_peer_addr_type, 1114 sm_conn->sm_peer_address, 1115 setup->sm_peer_confirm, 1116 setup->sm_ra); 1117 } else { 1118 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1119 sm_conn->sm_peer_addr_type, 1120 sm_conn->sm_peer_address, 1121 setup->sm_peer_confirm, 1122 setup->sm_rb); 1123 } 1124 } else { 1125 setup->sm_have_oob_data = 0; 1126 } 1127 } 1128 #endif 1129 1130 sm_pairing_packet_t * local_packet; 1131 if (IS_RESPONDER(sm_conn->sm_role)){ 1132 // slave 1133 local_packet = &setup->sm_s_pres; 1134 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1135 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1136 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1137 } else { 1138 // master 1139 local_packet = &setup->sm_m_preq; 1140 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1141 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1142 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1143 1144 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1145 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1146 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1147 } 1148 1149 uint8_t auth_req = sm_auth_req & ~SM_AUTHREQ_CT2; 1150 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1151 // set CT2 if SC + Bonding + CTKD 1152 const uint8_t auth_req_for_ct2 = SM_AUTHREQ_SECURE_CONNECTION | SM_AUTHREQ_BONDING; 1153 if ((auth_req & auth_req_for_ct2) == auth_req_for_ct2){ 1154 auth_req |= SM_AUTHREQ_CT2; 1155 } 1156 #endif 1157 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1158 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1159 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1160 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1161 } 1162 1163 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1164 1165 sm_pairing_packet_t * remote_packet; 1166 int remote_key_request; 1167 if (IS_RESPONDER(sm_conn->sm_role)){ 1168 // slave / responder 1169 remote_packet = &setup->sm_m_preq; 1170 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1171 } else { 1172 // master / initiator 1173 remote_packet = &setup->sm_s_pres; 1174 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1175 } 1176 1177 // check key size 1178 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1179 if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; 1180 1181 // decide on STK generation method / SC 1182 sm_setup_tk(); 1183 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1184 1185 // check if STK generation method is acceptable by client 1186 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1187 1188 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1189 // check LE SC Only mode 1190 if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ 1191 log_info("SC Only mode active but SC not possible"); 1192 return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1193 } 1194 1195 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1196 if (setup->sm_use_secure_connections){ 1197 remote_key_request &= ~SM_KEYDIST_ENC_KEY; 1198 } 1199 #endif 1200 1201 // identical to responder 1202 sm_setup_key_distribution(remote_key_request); 1203 1204 // JUST WORKS doens't provide authentication 1205 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1206 1207 return 0; 1208 } 1209 1210 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1211 1212 // cache and reset context 1213 int matched_device_id = sm_address_resolution_test; 1214 address_resolution_mode_t mode = sm_address_resolution_mode; 1215 void * context = sm_address_resolution_context; 1216 1217 // reset context 1218 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1219 sm_address_resolution_context = NULL; 1220 sm_address_resolution_test = -1; 1221 hci_con_handle_t con_handle = 0; 1222 1223 sm_connection_t * sm_connection; 1224 sm_key_t ltk; 1225 int have_ltk; 1226 #ifdef ENABLE_LE_CENTRAL 1227 int trigger_pairing; 1228 #endif 1229 switch (mode){ 1230 case ADDRESS_RESOLUTION_GENERAL: 1231 break; 1232 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1233 sm_connection = (sm_connection_t *) context; 1234 con_handle = sm_connection->sm_handle; 1235 1236 // have ltk -> start encryption / send security request 1237 // Core 5, Vol 3, Part C, 10.3.2 Initiating a Service Request 1238 // "When a bond has been created between two devices, any reconnection should result in the local device 1239 // enabling or requesting encryption with the remote device before initiating any service request." 1240 1241 switch (event){ 1242 case ADDRESS_RESOLUTION_SUCCEEDED: 1243 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1244 sm_connection->sm_le_db_index = matched_device_id; 1245 log_info("ADDRESS_RESOLUTION_SUCCEEDED, index %d", sm_connection->sm_le_db_index); 1246 1247 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1248 have_ltk = !sm_is_null_key(ltk); 1249 1250 if (sm_connection->sm_role) { 1251 1252 #ifdef ENABLE_LE_PERIPHERAL 1253 1254 // LTK request received before, IRK required -> start LTK calculation 1255 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1256 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1257 break; 1258 } 1259 1260 if (have_ltk) { 1261 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1262 log_info("central: enable encryption for bonded device"); 1263 sm_connection->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 1264 sm_notify_client_reencryption_started(sm_connection); 1265 sm_trigger_run(); 1266 #else 1267 log_info("central: defer security request for bonded device"); 1268 #endif 1269 } 1270 #endif 1271 } else { 1272 1273 #ifdef ENABLE_LE_CENTRAL 1274 1275 // check if pairing already requested and reset requests 1276 trigger_pairing = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1277 log_info("central: pairing request local %u, remote %u => trigger_pairing %u. have_ltk %u", 1278 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, trigger_pairing, have_ltk); 1279 sm_connection->sm_security_request_received = 0; 1280 sm_connection->sm_pairing_requested = 0; 1281 bool trigger_reencryption = false; 1282 1283 if (have_ltk){ 1284 #ifdef ENABLE_LE_PROACTIVE_AUTHENTICATION 1285 trgigger_reencryptipm = true; 1286 #else 1287 if (trigger_pairing){ 1288 trigger_reencryption = true; 1289 } else { 1290 log_info("central: defer enabling encryption for bonded device"); 1291 } 1292 #endif 1293 } 1294 1295 if (trigger_reencryption){ 1296 log_info("central: enable encryption for bonded device"); 1297 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1298 sm_notify_client_reencryption_started(sm_connection); 1299 break; 1300 } 1301 1302 // pairing_request -> send pairing request 1303 if (trigger_pairing){ 1304 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1305 break; 1306 } 1307 } 1308 #endif 1309 break; 1310 case ADDRESS_RESOLUTION_FAILED: 1311 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1312 if (sm_connection->sm_role) { 1313 // LTK request received before, IRK required -> negative LTK reply 1314 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1315 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1316 } 1317 break; 1318 } 1319 #ifdef ENABLE_LE_CENTRAL 1320 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1321 sm_connection->sm_security_request_received = 0; 1322 sm_connection->sm_pairing_requested = 0; 1323 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1324 #endif 1325 break; 1326 1327 default: 1328 btstack_assert(false); 1329 break; 1330 } 1331 break; 1332 default: 1333 break; 1334 } 1335 1336 switch (event){ 1337 case ADDRESS_RESOLUTION_SUCCEEDED: 1338 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1339 break; 1340 case ADDRESS_RESOLUTION_FAILED: 1341 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1342 break; 1343 default: 1344 btstack_assert(false); 1345 break; 1346 } 1347 } 1348 1349 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1350 1351 int le_db_index = -1; 1352 1353 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1354 int bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1355 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1356 & SM_AUTHREQ_BONDING ) != 0u; 1357 1358 if (bonding_enabed){ 1359 1360 // lookup device based on IRK 1361 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1362 int i; 1363 for (i=0; i < le_device_db_max_count(); i++){ 1364 sm_key_t irk; 1365 bd_addr_t address; 1366 int address_type = BD_ADDR_TYPE_UNKNOWN; 1367 le_device_db_info(i, &address_type, address, irk); 1368 // skip unused entries 1369 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1370 // compare IRK 1371 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1372 1373 log_info("sm: device found for IRK, updating"); 1374 le_db_index = i; 1375 break; 1376 } 1377 } else { 1378 // assert IRK is set to zero 1379 memset(setup->sm_peer_irk, 0, 16); 1380 } 1381 1382 // if not found, lookup via public address if possible 1383 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1384 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1385 int i; 1386 for (i=0; i < le_device_db_max_count(); i++){ 1387 bd_addr_t address; 1388 int address_type = BD_ADDR_TYPE_UNKNOWN; 1389 le_device_db_info(i, &address_type, address, NULL); 1390 // skip unused entries 1391 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1392 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1393 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1394 log_info("sm: device found for public address, updating"); 1395 le_db_index = i; 1396 break; 1397 } 1398 } 1399 } 1400 1401 // if not found, add to db 1402 bool new_to_le_device_db = false; 1403 if (le_db_index < 0) { 1404 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1405 new_to_le_device_db = true; 1406 } 1407 1408 if (le_db_index >= 0){ 1409 1410 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1411 if (!new_to_le_device_db){ 1412 hci_remove_le_device_db_entry_from_resolving_list(le_db_index); 1413 } 1414 hci_load_le_device_db_entry_into_resolving_list(le_db_index); 1415 #else 1416 UNUSED(new_to_le_device_db); 1417 #endif 1418 1419 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1420 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1421 1422 #ifdef ENABLE_LE_SIGNED_WRITE 1423 // store local CSRK 1424 setup->sm_le_device_index = le_db_index; 1425 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1426 log_info("sm: store local CSRK"); 1427 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1428 le_device_db_local_counter_set(le_db_index, 0); 1429 } 1430 1431 // store remote CSRK 1432 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1433 log_info("sm: store remote CSRK"); 1434 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1435 le_device_db_remote_counter_set(le_db_index, 0); 1436 } 1437 #endif 1438 // store encryption information for secure connections: LTK generated by ECDH 1439 if (setup->sm_use_secure_connections){ 1440 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1441 uint8_t zero_rand[8]; 1442 memset(zero_rand, 0, 8); 1443 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1444 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1445 } 1446 1447 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1448 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1449 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1450 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1451 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1452 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1453 1454 } 1455 } 1456 } else { 1457 log_info("Ignoring received keys, bonding not enabled"); 1458 } 1459 1460 // keep le_db_index 1461 sm_conn->sm_le_db_index = le_db_index; 1462 } 1463 1464 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1465 setup->sm_pairing_failed_reason = reason; 1466 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1467 } 1468 1469 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1470 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1471 } 1472 1473 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1474 1475 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1476 static int sm_passkey_used(stk_generation_method_t method); 1477 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1478 1479 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1480 if (setup->sm_stk_generation_method == OOB){ 1481 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1482 } else { 1483 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); 1484 } 1485 } 1486 1487 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1488 if (IS_RESPONDER(sm_conn->sm_role)){ 1489 // Responder 1490 if (setup->sm_stk_generation_method == OOB){ 1491 // generate Nb 1492 log_info("Generate Nb"); 1493 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); 1494 } else { 1495 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1496 } 1497 } else { 1498 // Initiator role 1499 switch (setup->sm_stk_generation_method){ 1500 case JUST_WORKS: 1501 sm_sc_prepare_dhkey_check(sm_conn); 1502 break; 1503 1504 case NUMERIC_COMPARISON: 1505 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1506 break; 1507 case PK_INIT_INPUT: 1508 case PK_RESP_INPUT: 1509 case PK_BOTH_INPUT: 1510 if (setup->sm_passkey_bit < 20u) { 1511 sm_sc_start_calculating_local_confirm(sm_conn); 1512 } else { 1513 sm_sc_prepare_dhkey_check(sm_conn); 1514 } 1515 break; 1516 case OOB: 1517 sm_sc_prepare_dhkey_check(sm_conn); 1518 break; 1519 default: 1520 btstack_assert(false); 1521 break; 1522 } 1523 } 1524 } 1525 1526 static void sm_sc_cmac_done(uint8_t * hash){ 1527 log_info("sm_sc_cmac_done: "); 1528 log_info_hexdump(hash, 16); 1529 1530 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1531 sm_sc_oob_state = SM_SC_OOB_IDLE; 1532 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1533 return; 1534 } 1535 1536 sm_connection_t * sm_conn = sm_cmac_connection; 1537 sm_cmac_connection = NULL; 1538 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1539 link_key_type_t link_key_type; 1540 #endif 1541 1542 switch (sm_conn->sm_engine_state){ 1543 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1544 (void)memcpy(setup->sm_local_confirm, hash, 16); 1545 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1546 break; 1547 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1548 // check 1549 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1550 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1551 break; 1552 } 1553 sm_sc_state_after_receiving_random(sm_conn); 1554 break; 1555 case SM_SC_W4_CALCULATE_G2: { 1556 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1557 big_endian_store_32(setup->sm_tk, 12, vab); 1558 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1559 sm_trigger_user_response(sm_conn); 1560 break; 1561 } 1562 case SM_SC_W4_CALCULATE_F5_SALT: 1563 (void)memcpy(setup->sm_t, hash, 16); 1564 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1565 break; 1566 case SM_SC_W4_CALCULATE_F5_MACKEY: 1567 (void)memcpy(setup->sm_mackey, hash, 16); 1568 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1569 break; 1570 case SM_SC_W4_CALCULATE_F5_LTK: 1571 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1572 // Errata Service Release to the Bluetooth Specification: ESR09 1573 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1574 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1575 (void)memcpy(setup->sm_ltk, hash, 16); 1576 (void)memcpy(setup->sm_local_ltk, hash, 16); 1577 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1578 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1579 break; 1580 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1581 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1582 if (IS_RESPONDER(sm_conn->sm_role)){ 1583 // responder 1584 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1585 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1586 } else { 1587 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1588 } 1589 } else { 1590 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1591 } 1592 break; 1593 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1594 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1595 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1596 break; 1597 } 1598 if (IS_RESPONDER(sm_conn->sm_role)){ 1599 // responder 1600 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1601 } else { 1602 // initiator 1603 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1604 } 1605 break; 1606 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1607 case SM_SC_W4_CALCULATE_ILK: 1608 (void)memcpy(setup->sm_t, hash, 16); 1609 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY; 1610 break; 1611 case SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY: 1612 reverse_128(hash, setup->sm_t); 1613 link_key_type = sm_conn->sm_connection_authenticated ? 1614 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1615 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1616 gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); 1617 if (IS_RESPONDER(sm_conn->sm_role)){ 1618 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1619 } else { 1620 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1621 } 1622 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 1623 sm_done_for_handle(sm_conn->sm_handle); 1624 break; 1625 #endif 1626 default: 1627 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1628 break; 1629 } 1630 sm_trigger_run(); 1631 } 1632 1633 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){ 1634 const uint16_t message_len = 65; 1635 sm_cmac_connection = sm_conn; 1636 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1637 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1638 sm_cmac_sc_buffer[64] = z; 1639 log_info("f4 key"); 1640 log_info_hexdump(x, 16); 1641 log_info("f4 message"); 1642 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1643 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1644 } 1645 1646 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1647 static const uint8_t f5_length[] = { 0x01, 0x00}; 1648 1649 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1650 1651 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1652 1653 log_info("f5_calculate_salt"); 1654 // calculate salt for f5 1655 const uint16_t message_len = 32; 1656 sm_cmac_connection = sm_conn; 1657 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1658 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1659 } 1660 1661 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){ 1662 const uint16_t message_len = 53; 1663 sm_cmac_connection = sm_conn; 1664 1665 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1666 sm_cmac_sc_buffer[0] = 0; 1667 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1668 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1669 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1670 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1671 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1672 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1673 log_info("f5 key"); 1674 log_info_hexdump(t, 16); 1675 log_info("f5 message for MacKey"); 1676 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1677 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1678 } 1679 1680 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1681 sm_key56_t bd_addr_master, bd_addr_slave; 1682 bd_addr_master[0] = setup->sm_m_addr_type; 1683 bd_addr_slave[0] = setup->sm_s_addr_type; 1684 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1685 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1686 if (IS_RESPONDER(sm_conn->sm_role)){ 1687 // responder 1688 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1689 } else { 1690 // initiator 1691 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1692 } 1693 } 1694 1695 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1696 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1697 const uint16_t message_len = 53; 1698 sm_cmac_connection = sm_conn; 1699 sm_cmac_sc_buffer[0] = 1; 1700 // 1..52 setup before 1701 log_info("f5 key"); 1702 log_info_hexdump(t, 16); 1703 log_info("f5 message for LTK"); 1704 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1705 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1706 } 1707 1708 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1709 f5_ltk(sm_conn, setup->sm_t); 1710 } 1711 1712 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){ 1713 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1714 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1715 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1716 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1717 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1718 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1719 } 1720 1721 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ 1722 const uint16_t message_len = 65; 1723 sm_cmac_connection = sm_conn; 1724 log_info("f6 key"); 1725 log_info_hexdump(w, 16); 1726 log_info("f6 message"); 1727 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1728 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1729 } 1730 1731 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1732 // - U is 256 bits 1733 // - V is 256 bits 1734 // - X is 128 bits 1735 // - Y is 128 bits 1736 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){ 1737 const uint16_t message_len = 80; 1738 sm_cmac_connection = sm_conn; 1739 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1740 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1741 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1742 log_info("g2 key"); 1743 log_info_hexdump(x, 16); 1744 log_info("g2 message"); 1745 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1746 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1747 } 1748 1749 static void g2_calculate(sm_connection_t * sm_conn) { 1750 // calc Va if numeric comparison 1751 if (IS_RESPONDER(sm_conn->sm_role)){ 1752 // responder 1753 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1754 } else { 1755 // initiator 1756 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1757 } 1758 } 1759 1760 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1761 uint8_t z = 0; 1762 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1763 // some form of passkey 1764 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1765 z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); 1766 setup->sm_passkey_bit++; 1767 } 1768 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1769 } 1770 1771 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1772 // OOB 1773 if (setup->sm_stk_generation_method == OOB){ 1774 if (IS_RESPONDER(sm_conn->sm_role)){ 1775 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1776 } else { 1777 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1778 } 1779 return; 1780 } 1781 1782 uint8_t z = 0; 1783 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1784 // some form of passkey 1785 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1786 // sm_passkey_bit was increased before sending confirm value 1787 z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); 1788 } 1789 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1790 } 1791 1792 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1793 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) ? 1 : 0); 1794 1795 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1796 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1797 return; 1798 } else { 1799 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1800 } 1801 } 1802 1803 static void sm_sc_dhkey_calculated(void * arg){ 1804 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1805 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1806 if (sm_conn == NULL) return; 1807 1808 log_info("dhkey"); 1809 log_info_hexdump(&setup->sm_dhkey[0], 32); 1810 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1811 // trigger next step 1812 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1813 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1814 } 1815 sm_trigger_run(); 1816 } 1817 1818 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1819 // calculate DHKCheck 1820 sm_key56_t bd_addr_master, bd_addr_slave; 1821 bd_addr_master[0] = setup->sm_m_addr_type; 1822 bd_addr_slave[0] = setup->sm_s_addr_type; 1823 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1824 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1825 uint8_t iocap_a[3]; 1826 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1827 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1828 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1829 uint8_t iocap_b[3]; 1830 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1831 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1832 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1833 if (IS_RESPONDER(sm_conn->sm_role)){ 1834 // responder 1835 f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1836 f6_engine(sm_conn, setup->sm_mackey); 1837 } else { 1838 // initiator 1839 f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1840 f6_engine(sm_conn, setup->sm_mackey); 1841 } 1842 } 1843 1844 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1845 // validate E = f6() 1846 sm_key56_t bd_addr_master, bd_addr_slave; 1847 bd_addr_master[0] = setup->sm_m_addr_type; 1848 bd_addr_slave[0] = setup->sm_s_addr_type; 1849 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1850 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1851 1852 uint8_t iocap_a[3]; 1853 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1854 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1855 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1856 uint8_t iocap_b[3]; 1857 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1858 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1859 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1860 if (IS_RESPONDER(sm_conn->sm_role)){ 1861 // responder 1862 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1863 f6_engine(sm_conn, setup->sm_mackey); 1864 } else { 1865 // initiator 1866 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1867 f6_engine(sm_conn, setup->sm_mackey); 1868 } 1869 } 1870 1871 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1872 1873 // 1874 // Link Key Conversion Function h6 1875 // 1876 // h6(W, keyID) = AES-CMAC_W(keyID) 1877 // - W is 128 bits 1878 // - keyID is 32 bits 1879 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1880 const uint16_t message_len = 4; 1881 sm_cmac_connection = sm_conn; 1882 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1883 log_info("h6 key"); 1884 log_info_hexdump(w, 16); 1885 log_info("h6 message"); 1886 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1887 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1888 } 1889 // 1890 // Link Key Conversion Function h7 1891 // 1892 // h7(SALT, W) = AES-CMAC_SALT(W) 1893 // - SALT is 128 bits 1894 // - W is 128 bits 1895 static void h7_engine(sm_connection_t * sm_conn, const sm_key_t salt, const sm_key_t w) { 1896 const uint16_t message_len = 16; 1897 sm_cmac_connection = sm_conn; 1898 log_info("h7 key"); 1899 log_info_hexdump(salt, 16); 1900 log_info("h7 message"); 1901 log_info_hexdump(w, 16); 1902 sm_cmac_message_start(salt, message_len, w, &sm_sc_cmac_done); 1903 } 1904 1905 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1906 // Errata Service Release to the Bluetooth Specification: ESR09 1907 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1908 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1909 1910 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1911 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1912 } 1913 1914 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1915 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1916 } 1917 1918 static void h7_calculate_ilk(sm_connection_t * sm_conn){ 1919 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x31}; // "tmp1" 1920 h7_engine(sm_conn, salt, setup->sm_local_ltk); 1921 } 1922 #endif 1923 1924 #endif 1925 1926 // key management legacy connections: 1927 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1928 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1929 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1930 // - responder reconnects: responder uses LTK receveived from master 1931 1932 // key management secure connections: 1933 // - both devices store same LTK from ECDH key exchange. 1934 1935 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1936 static void sm_load_security_info(sm_connection_t * sm_connection){ 1937 int encryption_key_size; 1938 int authenticated; 1939 int authorized; 1940 int secure_connection; 1941 1942 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1943 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1944 &encryption_key_size, &authenticated, &authorized, &secure_connection); 1945 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); 1946 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1947 sm_connection->sm_connection_authenticated = authenticated; 1948 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1949 sm_connection->sm_connection_sc = secure_connection; 1950 } 1951 #endif 1952 1953 #ifdef ENABLE_LE_PERIPHERAL 1954 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1955 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1956 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1957 // re-establish used key encryption size 1958 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1959 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; 1960 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1961 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; 1962 // Legacy paring -> not SC 1963 sm_connection->sm_connection_sc = 0; 1964 log_info("sm: received ltk request with key size %u, authenticated %u", 1965 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1966 } 1967 #endif 1968 1969 // distributed key generation 1970 static bool sm_run_dpkg(void){ 1971 switch (dkg_state){ 1972 case DKG_CALC_IRK: 1973 // already busy? 1974 if (sm_aes128_state == SM_AES128_IDLE) { 1975 log_info("DKG_CALC_IRK started"); 1976 // IRK = d1(IR, 1, 0) 1977 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 1978 sm_aes128_state = SM_AES128_ACTIVE; 1979 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 1980 return true; 1981 } 1982 break; 1983 case DKG_CALC_DHK: 1984 // already busy? 1985 if (sm_aes128_state == SM_AES128_IDLE) { 1986 log_info("DKG_CALC_DHK started"); 1987 // DHK = d1(IR, 3, 0) 1988 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 1989 sm_aes128_state = SM_AES128_ACTIVE; 1990 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 1991 return true; 1992 } 1993 break; 1994 default: 1995 break; 1996 } 1997 return false; 1998 } 1999 2000 // random address updates 2001 static bool sm_run_rau(void){ 2002 switch (rau_state){ 2003 case RAU_GET_RANDOM: 2004 rau_state = RAU_W4_RANDOM; 2005 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 2006 return true; 2007 case RAU_GET_ENC: 2008 // already busy? 2009 if (sm_aes128_state == SM_AES128_IDLE) { 2010 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 2011 sm_aes128_state = SM_AES128_ACTIVE; 2012 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 2013 return true; 2014 } 2015 break; 2016 case RAU_SET_ADDRESS: 2017 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 2018 rau_state = RAU_IDLE; 2019 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 2020 return true; 2021 default: 2022 break; 2023 } 2024 return false; 2025 } 2026 2027 // CSRK Lookup 2028 static bool sm_run_csrk(void){ 2029 btstack_linked_list_iterator_t it; 2030 2031 // -- if csrk lookup ready, find connection that require csrk lookup 2032 if (sm_address_resolution_idle()){ 2033 hci_connections_get_iterator(&it); 2034 while(btstack_linked_list_iterator_has_next(&it)){ 2035 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2036 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2037 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 2038 // and start lookup 2039 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); 2040 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 2041 break; 2042 } 2043 } 2044 } 2045 2046 // -- if csrk lookup ready, resolved addresses for received addresses 2047 if (sm_address_resolution_idle()) { 2048 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 2049 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 2050 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 2051 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 2052 btstack_memory_sm_lookup_entry_free(entry); 2053 } 2054 } 2055 2056 // -- Continue with CSRK device lookup by public or resolvable private address 2057 if (!sm_address_resolution_idle()){ 2058 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 2059 while (sm_address_resolution_test < le_device_db_max_count()){ 2060 int addr_type = BD_ADDR_TYPE_UNKNOWN; 2061 bd_addr_t addr; 2062 sm_key_t irk; 2063 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2064 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 2065 2066 // skip unused entries 2067 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 2068 sm_address_resolution_test++; 2069 continue; 2070 } 2071 2072 if ((sm_address_resolution_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 2073 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 2074 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 2075 break; 2076 } 2077 2078 // if connection type is public, it must be a different one 2079 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 2080 sm_address_resolution_test++; 2081 continue; 2082 } 2083 2084 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2085 2086 log_info("LE Device Lookup: calculate AH"); 2087 log_info_key("IRK", irk); 2088 2089 (void)memcpy(sm_aes128_key, irk, 16); 2090 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 2091 sm_address_resolution_ah_calculation_active = 1; 2092 sm_aes128_state = SM_AES128_ACTIVE; 2093 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 2094 return true; 2095 } 2096 2097 if (sm_address_resolution_test >= le_device_db_max_count()){ 2098 log_info("LE Device Lookup: not found"); 2099 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2100 } 2101 } 2102 return false; 2103 } 2104 2105 // SC OOB 2106 static bool sm_run_oob(void){ 2107 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2108 switch (sm_sc_oob_state){ 2109 case SM_SC_OOB_W2_CALC_CONFIRM: 2110 if (!sm_cmac_ready()) break; 2111 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2112 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2113 return true; 2114 default: 2115 break; 2116 } 2117 #endif 2118 return false; 2119 } 2120 2121 // handle basic actions that don't requires the full context 2122 static bool sm_run_basic(void){ 2123 btstack_linked_list_iterator_t it; 2124 hci_connections_get_iterator(&it); 2125 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2126 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2127 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2128 switch(sm_connection->sm_engine_state){ 2129 // responder side 2130 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2131 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2132 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2133 return true; 2134 2135 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2136 case SM_SC_RECEIVED_LTK_REQUEST: 2137 switch (sm_connection->sm_irk_lookup_state){ 2138 case IRK_LOOKUP_FAILED: 2139 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 2140 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2141 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2142 return true; 2143 default: 2144 break; 2145 } 2146 break; 2147 #endif 2148 default: 2149 break; 2150 } 2151 } 2152 return false; 2153 } 2154 2155 static void sm_run_activate_connection(void){ 2156 // Find connections that requires setup context and make active if no other is locked 2157 btstack_linked_list_iterator_t it; 2158 hci_connections_get_iterator(&it); 2159 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2160 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2161 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2162 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2163 int done = 1; 2164 int err; 2165 UNUSED(err); 2166 2167 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2168 // assert ec key is ready 2169 if ( (sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2170 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST) 2171 || (sm_connection->sm_engine_state == SM_RESPONDER_SEND_SECURITY_REQUEST)){ 2172 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2173 sm_ec_generate_new_key(); 2174 } 2175 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2176 continue; 2177 } 2178 } 2179 #endif 2180 2181 switch (sm_connection->sm_engine_state) { 2182 #ifdef ENABLE_LE_PERIPHERAL 2183 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2184 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2185 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2186 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2187 case SM_SC_RECEIVED_LTK_REQUEST: 2188 #endif 2189 #endif 2190 #ifdef ENABLE_LE_CENTRAL 2191 case SM_INITIATOR_PH0_HAS_LTK: 2192 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2193 #endif 2194 // just lock context 2195 break; 2196 default: 2197 done = 0; 2198 break; 2199 } 2200 if (done){ 2201 sm_active_connection_handle = sm_connection->sm_handle; 2202 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); 2203 } 2204 } 2205 } 2206 2207 static void sm_run(void){ 2208 2209 // assert that stack has already bootet 2210 if (hci_get_state() != HCI_STATE_WORKING) return; 2211 2212 // assert that we can send at least commands 2213 if (!hci_can_send_command_packet_now()) return; 2214 2215 // pause until IR/ER are ready 2216 if (sm_persistent_keys_random_active) return; 2217 2218 bool done; 2219 2220 // 2221 // non-connection related behaviour 2222 // 2223 2224 done = sm_run_dpkg(); 2225 if (done) return; 2226 2227 done = sm_run_rau(); 2228 if (done) return; 2229 2230 done = sm_run_csrk(); 2231 if (done) return; 2232 2233 done = sm_run_oob(); 2234 if (done) return; 2235 2236 // assert that we can send at least commands - cmd might have been sent by crypto engine 2237 if (!hci_can_send_command_packet_now()) return; 2238 2239 // handle basic actions that don't requires the full context 2240 done = sm_run_basic(); 2241 if (done) return; 2242 2243 // 2244 // active connection handling 2245 // -- use loop to handle next connection if lock on setup context is released 2246 2247 while (true) { 2248 2249 sm_run_activate_connection(); 2250 2251 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2252 2253 // 2254 // active connection handling 2255 // 2256 2257 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2258 if (!connection) { 2259 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2260 return; 2261 } 2262 2263 // assert that we could send a SM PDU - not needed for all of the following 2264 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2265 log_info("cannot send now, requesting can send now event"); 2266 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2267 return; 2268 } 2269 2270 // send keypress notifications 2271 if (setup->sm_keypress_notification){ 2272 int i; 2273 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2274 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2275 uint8_t action = 0; 2276 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2277 if (flags & (1u<<i)){ 2278 int clear_flag = 1; 2279 switch (i){ 2280 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2281 case SM_KEYPRESS_PASSKEY_CLEARED: 2282 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2283 default: 2284 break; 2285 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2286 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2287 num_actions--; 2288 clear_flag = num_actions == 0u; 2289 break; 2290 } 2291 if (clear_flag){ 2292 flags &= ~(1<<i); 2293 } 2294 action = i; 2295 break; 2296 } 2297 } 2298 setup->sm_keypress_notification = (num_actions << 5) | flags; 2299 2300 // send keypress notification 2301 uint8_t buffer[2]; 2302 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2303 buffer[1] = action; 2304 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2305 2306 // try 2307 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2308 return; 2309 } 2310 2311 int key_distribution_flags; 2312 UNUSED(key_distribution_flags); 2313 int err; 2314 UNUSED(err); 2315 2316 log_info("sm_run: state %u", connection->sm_engine_state); 2317 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2318 log_info("sm_run // cannot send"); 2319 } 2320 switch (connection->sm_engine_state){ 2321 2322 // general 2323 case SM_GENERAL_SEND_PAIRING_FAILED: { 2324 uint8_t buffer[2]; 2325 buffer[0] = SM_CODE_PAIRING_FAILED; 2326 buffer[1] = setup->sm_pairing_failed_reason; 2327 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2328 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2329 sm_notify_client_status_reason(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2330 sm_done_for_handle(connection->sm_handle); 2331 break; 2332 } 2333 2334 // secure connections, initiator + responding states 2335 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2336 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2337 if (!sm_cmac_ready()) break; 2338 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2339 sm_sc_calculate_local_confirm(connection); 2340 break; 2341 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2342 if (!sm_cmac_ready()) break; 2343 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2344 sm_sc_calculate_remote_confirm(connection); 2345 break; 2346 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2347 if (!sm_cmac_ready()) break; 2348 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2349 sm_sc_calculate_f6_for_dhkey_check(connection); 2350 break; 2351 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2352 if (!sm_cmac_ready()) break; 2353 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2354 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2355 break; 2356 case SM_SC_W2_CALCULATE_F5_SALT: 2357 if (!sm_cmac_ready()) break; 2358 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2359 f5_calculate_salt(connection); 2360 break; 2361 case SM_SC_W2_CALCULATE_F5_MACKEY: 2362 if (!sm_cmac_ready()) break; 2363 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2364 f5_calculate_mackey(connection); 2365 break; 2366 case SM_SC_W2_CALCULATE_F5_LTK: 2367 if (!sm_cmac_ready()) break; 2368 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2369 f5_calculate_ltk(connection); 2370 break; 2371 case SM_SC_W2_CALCULATE_G2: 2372 if (!sm_cmac_ready()) break; 2373 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2374 g2_calculate(connection); 2375 break; 2376 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2377 case SM_SC_W2_CALCULATE_ILK_USING_H6: 2378 if (!sm_cmac_ready()) break; 2379 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 2380 h6_calculate_ilk(connection); 2381 break; 2382 case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: 2383 if (!sm_cmac_ready()) break; 2384 connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; 2385 h6_calculate_br_edr_link_key(connection); 2386 break; 2387 case SM_SC_W2_CALCULATE_ILK_USING_H7: 2388 if (!sm_cmac_ready()) break; 2389 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 2390 h7_calculate_ilk(connection); 2391 break; 2392 #endif 2393 #endif 2394 2395 #ifdef ENABLE_LE_CENTRAL 2396 // initiator side 2397 2398 case SM_INITIATOR_PH0_HAS_LTK: { 2399 sm_reset_setup(); 2400 sm_load_security_info(connection); 2401 2402 sm_key_t peer_ltk_flipped; 2403 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2404 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2405 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2406 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2407 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2408 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2409 return; 2410 } 2411 2412 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2413 sm_reset_setup(); 2414 sm_init_setup(connection); 2415 sm_timeout_start(connection); 2416 2417 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2418 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2419 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2420 sm_timeout_reset(connection); 2421 break; 2422 #endif 2423 2424 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2425 2426 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2427 int trigger_user_response = 0; 2428 int trigger_start_calculating_local_confirm = 0; 2429 uint8_t buffer[65]; 2430 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2431 // 2432 reverse_256(&ec_q[0], &buffer[1]); 2433 reverse_256(&ec_q[32], &buffer[33]); 2434 2435 #ifdef ENABLE_TESTING_SUPPORT 2436 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2437 log_info("testing_support: invalidating public key"); 2438 // flip single bit of public key coordinate 2439 buffer[1] ^= 1; 2440 } 2441 #endif 2442 2443 // stk generation method 2444 // passkey entry: notify app to show passkey or to request passkey 2445 switch (setup->sm_stk_generation_method){ 2446 case JUST_WORKS: 2447 case NUMERIC_COMPARISON: 2448 if (IS_RESPONDER(connection->sm_role)){ 2449 // responder 2450 trigger_start_calculating_local_confirm = 1; 2451 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2452 } else { 2453 // initiator 2454 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2455 } 2456 break; 2457 case PK_INIT_INPUT: 2458 case PK_RESP_INPUT: 2459 case PK_BOTH_INPUT: 2460 // use random TK for display 2461 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2462 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2463 setup->sm_passkey_bit = 0; 2464 2465 if (IS_RESPONDER(connection->sm_role)){ 2466 // responder 2467 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2468 } else { 2469 // initiator 2470 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2471 } 2472 trigger_user_response = 1; 2473 break; 2474 case OOB: 2475 if (IS_RESPONDER(connection->sm_role)){ 2476 // responder 2477 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2478 } else { 2479 // initiator 2480 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2481 } 2482 break; 2483 default: 2484 btstack_assert(false); 2485 break; 2486 } 2487 2488 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2489 sm_timeout_reset(connection); 2490 2491 // trigger user response and calc confirm after sending pdu 2492 if (trigger_user_response){ 2493 sm_trigger_user_response(connection); 2494 } 2495 if (trigger_start_calculating_local_confirm){ 2496 sm_sc_start_calculating_local_confirm(connection); 2497 } 2498 break; 2499 } 2500 case SM_SC_SEND_CONFIRMATION: { 2501 uint8_t buffer[17]; 2502 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2503 reverse_128(setup->sm_local_confirm, &buffer[1]); 2504 if (IS_RESPONDER(connection->sm_role)){ 2505 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2506 } else { 2507 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2508 } 2509 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2510 sm_timeout_reset(connection); 2511 break; 2512 } 2513 case SM_SC_SEND_PAIRING_RANDOM: { 2514 uint8_t buffer[17]; 2515 buffer[0] = SM_CODE_PAIRING_RANDOM; 2516 reverse_128(setup->sm_local_nonce, &buffer[1]); 2517 log_info("stk method %u, num bits %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2518 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2519 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2520 if (IS_RESPONDER(connection->sm_role)){ 2521 // responder 2522 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2523 } else { 2524 // initiator 2525 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2526 } 2527 } else { 2528 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2529 if (IS_RESPONDER(connection->sm_role)){ 2530 // responder 2531 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2532 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2533 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2534 } else { 2535 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2536 sm_sc_prepare_dhkey_check(connection); 2537 } 2538 } else { 2539 // initiator 2540 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2541 } 2542 } 2543 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2544 sm_timeout_reset(connection); 2545 break; 2546 } 2547 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2548 uint8_t buffer[17]; 2549 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2550 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2551 2552 if (IS_RESPONDER(connection->sm_role)){ 2553 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2554 } else { 2555 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2556 } 2557 2558 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2559 sm_timeout_reset(connection); 2560 break; 2561 } 2562 2563 #endif 2564 2565 #ifdef ENABLE_LE_PERIPHERAL 2566 2567 case SM_RESPONDER_SEND_SECURITY_REQUEST: { 2568 const uint8_t buffer[2] = {SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2569 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2570 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t *) buffer, sizeof(buffer)); 2571 sm_timeout_start(connection); 2572 break; 2573 } 2574 2575 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2576 case SM_SC_RECEIVED_LTK_REQUEST: 2577 switch (connection->sm_irk_lookup_state){ 2578 case IRK_LOOKUP_SUCCEEDED: 2579 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2580 // start using context by loading security info 2581 sm_reset_setup(); 2582 sm_load_security_info(connection); 2583 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2584 (void)memcpy(setup->sm_ltk, setup->sm_peer_ltk, 16); 2585 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2586 sm_trigger_run(); 2587 break; 2588 } 2589 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2590 connection->sm_engine_state = SM_RESPONDER_IDLE; 2591 hci_send_cmd(&hci_le_long_term_key_negative_reply, connection->sm_handle); 2592 return; 2593 default: 2594 // just wait until IRK lookup is completed 2595 break; 2596 } 2597 break; 2598 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2599 2600 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2601 sm_reset_setup(); 2602 sm_init_setup(connection); 2603 // recover pairing request 2604 (void)memcpy(&setup->sm_m_preq, &connection->sm_m_preq, sizeof(sm_pairing_packet_t)); 2605 err = sm_stk_generation_init(connection); 2606 2607 #ifdef ENABLE_TESTING_SUPPORT 2608 if ((0 < test_pairing_failure) && (test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED)){ 2609 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2610 err = test_pairing_failure; 2611 } 2612 #endif 2613 if (err){ 2614 setup->sm_pairing_failed_reason = err; 2615 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2616 sm_trigger_run(); 2617 break; 2618 } 2619 2620 sm_timeout_start(connection); 2621 2622 // generate random number first, if we need to show passkey, otherwise send response 2623 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2624 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) connection->sm_handle); 2625 break; 2626 } 2627 2628 /* fall through */ 2629 2630 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2631 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2632 2633 // start with initiator key dist flags 2634 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2635 2636 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2637 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2638 if (setup->sm_use_secure_connections){ 2639 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2640 } 2641 #endif 2642 // setup in response 2643 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); 2644 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); 2645 2646 // update key distribution after ENC was dropped 2647 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2648 2649 if (setup->sm_use_secure_connections){ 2650 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2651 } else { 2652 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2653 } 2654 2655 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2656 sm_timeout_reset(connection); 2657 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2658 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 2659 sm_trigger_user_response(connection); 2660 } 2661 return; 2662 #endif 2663 2664 case SM_PH2_SEND_PAIRING_RANDOM: { 2665 uint8_t buffer[17]; 2666 buffer[0] = SM_CODE_PAIRING_RANDOM; 2667 reverse_128(setup->sm_local_random, &buffer[1]); 2668 if (IS_RESPONDER(connection->sm_role)){ 2669 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2670 } else { 2671 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2672 } 2673 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2674 sm_timeout_reset(connection); 2675 break; 2676 } 2677 2678 case SM_PH2_C1_GET_ENC_A: 2679 // already busy? 2680 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2681 // calculate confirm using aes128 engine - step 1 2682 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); 2683 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2684 sm_aes128_state = SM_AES128_ACTIVE; 2685 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); 2686 break; 2687 2688 case SM_PH2_C1_GET_ENC_C: 2689 // already busy? 2690 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2691 // calculate m_confirm using aes128 engine - step 1 2692 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); 2693 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2694 sm_aes128_state = SM_AES128_ACTIVE; 2695 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); 2696 break; 2697 2698 case SM_PH2_CALC_STK: 2699 // already busy? 2700 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2701 // calculate STK 2702 if (IS_RESPONDER(connection->sm_role)){ 2703 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2704 } else { 2705 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2706 } 2707 connection->sm_engine_state = SM_PH2_W4_STK; 2708 sm_aes128_state = SM_AES128_ACTIVE; 2709 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); 2710 break; 2711 2712 case SM_PH3_Y_GET_ENC: 2713 // already busy? 2714 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2715 // PH3B2 - calculate Y from - enc 2716 2717 // dm helper (was sm_dm_r_prime) 2718 // r' = padding || r 2719 // r - 64 bit value 2720 memset(&sm_aes128_plaintext[0], 0, 8); 2721 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2722 2723 // Y = dm(DHK, Rand) 2724 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2725 sm_aes128_state = SM_AES128_ACTIVE; 2726 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); 2727 break; 2728 2729 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2730 uint8_t buffer[17]; 2731 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2732 reverse_128(setup->sm_local_confirm, &buffer[1]); 2733 if (IS_RESPONDER(connection->sm_role)){ 2734 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2735 } else { 2736 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2737 } 2738 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2739 sm_timeout_reset(connection); 2740 return; 2741 } 2742 #ifdef ENABLE_LE_PERIPHERAL 2743 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2744 sm_key_t stk_flipped; 2745 reverse_128(setup->sm_ltk, stk_flipped); 2746 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2747 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2748 return; 2749 } 2750 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2751 sm_key_t ltk_flipped; 2752 reverse_128(setup->sm_ltk, ltk_flipped); 2753 connection->sm_engine_state = SM_RESPONDER_IDLE; 2754 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2755 sm_done_for_handle(connection->sm_handle); 2756 return; 2757 } 2758 2759 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2760 // already busy? 2761 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2762 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2763 2764 sm_reset_setup(); 2765 sm_start_calculating_ltk_from_ediv_and_rand(connection); 2766 2767 // dm helper (was sm_dm_r_prime) 2768 // r' = padding || r 2769 // r - 64 bit value 2770 memset(&sm_aes128_plaintext[0], 0, 8); 2771 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2772 2773 // Y = dm(DHK, Rand) 2774 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 2775 sm_aes128_state = SM_AES128_ACTIVE; 2776 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); 2777 return; 2778 #endif 2779 #ifdef ENABLE_LE_CENTRAL 2780 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2781 sm_key_t stk_flipped; 2782 reverse_128(setup->sm_ltk, stk_flipped); 2783 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2784 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2785 return; 2786 } 2787 #endif 2788 2789 case SM_PH3_DISTRIBUTE_KEYS: 2790 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2791 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2792 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2793 uint8_t buffer[17]; 2794 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2795 reverse_128(setup->sm_ltk, &buffer[1]); 2796 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2797 sm_timeout_reset(connection); 2798 return; 2799 } 2800 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2801 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2802 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2803 uint8_t buffer[11]; 2804 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2805 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2806 reverse_64(setup->sm_local_rand, &buffer[3]); 2807 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2808 sm_timeout_reset(connection); 2809 return; 2810 } 2811 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2812 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2813 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2814 uint8_t buffer[17]; 2815 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2816 reverse_128(sm_persistent_irk, &buffer[1]); 2817 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2818 sm_timeout_reset(connection); 2819 return; 2820 } 2821 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2822 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2823 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2824 bd_addr_t local_address; 2825 uint8_t buffer[8]; 2826 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2827 switch (gap_random_address_get_mode()){ 2828 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2829 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2830 // public or static random 2831 gap_le_get_own_address(&buffer[1], local_address); 2832 break; 2833 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2834 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2835 // fallback to public 2836 gap_local_bd_addr(local_address); 2837 buffer[1] = 0; 2838 break; 2839 default: 2840 btstack_assert(false); 2841 break; 2842 } 2843 reverse_bd_addr(local_address, &buffer[2]); 2844 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2845 sm_timeout_reset(connection); 2846 return; 2847 } 2848 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2849 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2850 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2851 2852 #ifdef ENABLE_LE_SIGNED_WRITE 2853 // hack to reproduce test runs 2854 if (test_use_fixed_local_csrk){ 2855 memset(setup->sm_local_csrk, 0xcc, 16); 2856 } 2857 2858 // store local CSRK 2859 if (setup->sm_le_device_index >= 0){ 2860 log_info("sm: store local CSRK"); 2861 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2862 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2863 } 2864 #endif 2865 2866 uint8_t buffer[17]; 2867 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2868 reverse_128(setup->sm_local_csrk, &buffer[1]); 2869 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2870 sm_timeout_reset(connection); 2871 return; 2872 } 2873 2874 // keys are sent 2875 if (IS_RESPONDER(connection->sm_role)){ 2876 // slave -> receive master keys if any 2877 if (sm_key_distribution_all_received(connection)){ 2878 sm_key_distribution_handle_all_received(connection); 2879 connection->sm_engine_state = SM_RESPONDER_IDLE; 2880 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2881 sm_done_for_handle(connection->sm_handle); 2882 } else { 2883 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2884 } 2885 } else { 2886 sm_master_pairing_success(connection); 2887 } 2888 break; 2889 2890 default: 2891 break; 2892 } 2893 2894 // check again if active connection was released 2895 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2896 } 2897 } 2898 2899 // sm_aes128_state stays active 2900 static void sm_handle_encryption_result_enc_a(void *arg){ 2901 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2902 sm_aes128_state = SM_AES128_IDLE; 2903 2904 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2905 if (connection == NULL) return; 2906 2907 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2908 sm_aes128_state = SM_AES128_ACTIVE; 2909 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); 2910 } 2911 2912 static void sm_handle_encryption_result_enc_b(void *arg){ 2913 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2914 sm_aes128_state = SM_AES128_IDLE; 2915 2916 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2917 if (connection == NULL) return; 2918 2919 log_info_key("c1!", setup->sm_local_confirm); 2920 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2921 sm_trigger_run(); 2922 } 2923 2924 // sm_aes128_state stays active 2925 static void sm_handle_encryption_result_enc_c(void *arg){ 2926 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2927 sm_aes128_state = SM_AES128_IDLE; 2928 2929 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2930 if (connection == NULL) return; 2931 2932 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2933 sm_aes128_state = SM_AES128_ACTIVE; 2934 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); 2935 } 2936 2937 static void sm_handle_encryption_result_enc_d(void * arg){ 2938 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2939 sm_aes128_state = SM_AES128_IDLE; 2940 2941 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2942 if (connection == NULL) return; 2943 2944 log_info_key("c1!", sm_aes128_ciphertext); 2945 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 2946 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2947 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2948 sm_trigger_run(); 2949 return; 2950 } 2951 if (IS_RESPONDER(connection->sm_role)){ 2952 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2953 sm_trigger_run(); 2954 } else { 2955 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2956 sm_aes128_state = SM_AES128_ACTIVE; 2957 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); 2958 } 2959 } 2960 2961 static void sm_handle_encryption_result_enc_stk(void *arg){ 2962 sm_aes128_state = SM_AES128_IDLE; 2963 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2964 2965 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2966 if (connection == NULL) return; 2967 2968 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2969 log_info_key("stk", setup->sm_ltk); 2970 if (IS_RESPONDER(connection->sm_role)){ 2971 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2972 } else { 2973 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2974 } 2975 sm_trigger_run(); 2976 } 2977 2978 // sm_aes128_state stays active 2979 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 2980 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2981 sm_aes128_state = SM_AES128_IDLE; 2982 2983 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2984 if (connection == NULL) return; 2985 2986 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2987 log_info_hex16("y", setup->sm_local_y); 2988 // PH3B3 - calculate EDIV 2989 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2990 log_info_hex16("ediv", setup->sm_local_ediv); 2991 // PH3B4 - calculate LTK - enc 2992 // LTK = d1(ER, DIV, 0)) 2993 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2994 sm_aes128_state = SM_AES128_ACTIVE; 2995 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); 2996 } 2997 2998 #ifdef ENABLE_LE_PERIPHERAL 2999 // sm_aes128_state stays active 3000 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 3001 sm_aes128_state = SM_AES128_IDLE; 3002 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3003 3004 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3005 if (connection == NULL) return; 3006 3007 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 3008 log_info_hex16("y", setup->sm_local_y); 3009 3010 // PH3B3 - calculate DIV 3011 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 3012 log_info_hex16("ediv", setup->sm_local_ediv); 3013 // PH3B4 - calculate LTK - enc 3014 // LTK = d1(ER, DIV, 0)) 3015 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 3016 sm_aes128_state = SM_AES128_ACTIVE; 3017 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); 3018 } 3019 #endif 3020 3021 // sm_aes128_state stays active 3022 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 3023 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3024 sm_aes128_state = SM_AES128_IDLE; 3025 3026 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3027 if (connection == NULL) return; 3028 3029 log_info_key("ltk", setup->sm_ltk); 3030 // calc CSRK next 3031 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 3032 sm_aes128_state = SM_AES128_ACTIVE; 3033 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_local_csrk, sm_handle_encryption_result_enc_csrk, (void *)(uintptr_t) connection->sm_handle); 3034 } 3035 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 3036 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 3037 // requirements to derive link key from LE: 3038 // - use secure connections 3039 if (setup->sm_use_secure_connections == 0) return false; 3040 // - bonding needs to be enabled: 3041 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; 3042 if (!bonding_enabled) return false; 3043 // - need identity address 3044 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0); 3045 if (!have_identity_address_info) return false; 3046 // - 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) 3047 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 3048 // If SC is authenticated, we consider it safe to overwrite a stored key. 3049 // 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. 3050 uint8_t link_key[16]; 3051 link_key_type_t link_key_type; 3052 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 3053 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type) != 0; 3054 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 3055 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 3056 return false; 3057 } 3058 // get started (all of the above are true) 3059 return true; 3060 #else 3061 UNUSED(sm_connection); 3062 return false; 3063 #endif 3064 } 3065 3066 static void sm_handle_encryption_result_enc_csrk(void *arg){ 3067 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3068 sm_aes128_state = SM_AES128_IDLE; 3069 3070 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3071 if (connection == NULL) return; 3072 3073 sm_aes128_state = SM_AES128_IDLE; 3074 log_info_key("csrk", setup->sm_local_csrk); 3075 if (setup->sm_key_distribution_send_set){ 3076 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3077 } else { 3078 // no keys to send, just continue 3079 if (IS_RESPONDER(connection->sm_role)){ 3080 // slave -> receive master keys 3081 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3082 } else { 3083 if (sm_ctkd_from_le(connection)){ 3084 bool use_h7 = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) & sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_CT2) != 0; 3085 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 3086 } else { 3087 sm_master_pairing_success(connection); 3088 } 3089 } 3090 } 3091 sm_trigger_run(); 3092 } 3093 3094 #ifdef ENABLE_LE_PERIPHERAL 3095 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 3096 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3097 sm_aes128_state = SM_AES128_IDLE; 3098 3099 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3100 if (connection == NULL) return; 3101 3102 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3103 log_info_key("ltk", setup->sm_ltk); 3104 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 3105 sm_trigger_run(); 3106 } 3107 #endif 3108 3109 static void sm_handle_encryption_result_address_resolution(void *arg){ 3110 UNUSED(arg); 3111 sm_aes128_state = SM_AES128_IDLE; 3112 3113 sm_address_resolution_ah_calculation_active = 0; 3114 // compare calulated address against connecting device 3115 uint8_t * hash = &sm_aes128_ciphertext[13]; 3116 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3117 log_info("LE Device Lookup: matched resolvable private address"); 3118 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCCEEDED); 3119 sm_trigger_run(); 3120 return; 3121 } 3122 // no match, try next 3123 sm_address_resolution_test++; 3124 sm_trigger_run(); 3125 } 3126 3127 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3128 UNUSED(arg); 3129 sm_aes128_state = SM_AES128_IDLE; 3130 3131 log_info_key("irk", sm_persistent_irk); 3132 dkg_state = DKG_CALC_DHK; 3133 sm_trigger_run(); 3134 } 3135 3136 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3137 UNUSED(arg); 3138 sm_aes128_state = SM_AES128_IDLE; 3139 3140 log_info_key("dhk", sm_persistent_dhk); 3141 dkg_state = DKG_READY; 3142 sm_trigger_run(); 3143 } 3144 3145 static void sm_handle_encryption_result_rau(void *arg){ 3146 UNUSED(arg); 3147 sm_aes128_state = SM_AES128_IDLE; 3148 3149 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3150 rau_state = RAU_SET_ADDRESS; 3151 sm_trigger_run(); 3152 } 3153 3154 static void sm_handle_random_result_rau(void * arg){ 3155 UNUSED(arg); 3156 // non-resolvable vs. resolvable 3157 switch (gap_random_adress_type){ 3158 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3159 // resolvable: use random as prand and calc address hash 3160 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3161 sm_random_address[0u] &= 0x3fu; 3162 sm_random_address[0u] |= 0x40u; 3163 rau_state = RAU_GET_ENC; 3164 break; 3165 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3166 default: 3167 // "The two most significant bits of the address shall be equal to ‘0’"" 3168 sm_random_address[0u] &= 0x3fu; 3169 rau_state = RAU_SET_ADDRESS; 3170 break; 3171 } 3172 sm_trigger_run(); 3173 } 3174 3175 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3176 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 3177 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3178 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3179 if (connection == NULL) return; 3180 3181 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3182 sm_trigger_run(); 3183 } 3184 3185 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3186 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3187 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3188 if (connection == NULL) return; 3189 3190 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3191 sm_trigger_run(); 3192 } 3193 #endif 3194 3195 static void sm_handle_random_result_ph2_random(void * arg){ 3196 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3197 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3198 if (connection == NULL) return; 3199 3200 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3201 sm_trigger_run(); 3202 } 3203 3204 static void sm_handle_random_result_ph2_tk(void * arg){ 3205 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3206 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3207 if (connection == NULL) return; 3208 3209 sm_reset_tk(); 3210 uint32_t tk; 3211 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 3212 // map random to 0-999999 without speding much cycles on a modulus operation 3213 tk = little_endian_read_32(sm_random_data,0); 3214 tk = tk & 0xfffff; // 1048575 3215 if (tk >= 999999u){ 3216 tk = tk - 999999u; 3217 } 3218 } else { 3219 // override with pre-defined passkey 3220 tk = sm_fixed_passkey_in_display_role; 3221 } 3222 big_endian_store_32(setup->sm_tk, 12, tk); 3223 if (IS_RESPONDER(connection->sm_role)){ 3224 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3225 } else { 3226 if (setup->sm_use_secure_connections){ 3227 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3228 } else { 3229 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3230 sm_trigger_user_response(connection); 3231 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3232 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3233 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); 3234 } 3235 } 3236 } 3237 sm_trigger_run(); 3238 } 3239 3240 static void sm_handle_random_result_ph3_div(void * arg){ 3241 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3242 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3243 if (connection == NULL) return; 3244 3245 // use 16 bit from random value as div 3246 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3247 log_info_hex16("div", setup->sm_local_div); 3248 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3249 sm_trigger_run(); 3250 } 3251 3252 static void sm_handle_random_result_ph3_random(void * arg){ 3253 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3254 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3255 if (connection == NULL) return; 3256 3257 reverse_64(sm_random_data, setup->sm_local_rand); 3258 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3259 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3260 // no db for authenticated flag hack: store flag in bit 4 of LSB 3261 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3262 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3263 } 3264 static void sm_validate_er_ir(void){ 3265 // warn about default ER/IR 3266 int warning = 0; 3267 if (sm_ir_is_default()){ 3268 warning = 1; 3269 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3270 } 3271 if (sm_er_is_default()){ 3272 warning = 1; 3273 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3274 } 3275 if (warning) { 3276 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3277 } 3278 } 3279 3280 static void sm_handle_random_result_ir(void *arg){ 3281 sm_persistent_keys_random_active = 0; 3282 if (arg){ 3283 // key generated, store in tlv 3284 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3285 log_info("Generated IR key. Store in TLV status: %d", status); 3286 UNUSED(status); 3287 } 3288 log_info_key("IR", sm_persistent_ir); 3289 dkg_state = DKG_CALC_IRK; 3290 3291 if (test_use_fixed_local_irk){ 3292 log_info_key("IRK", sm_persistent_irk); 3293 dkg_state = DKG_CALC_DHK; 3294 } 3295 3296 sm_trigger_run(); 3297 } 3298 3299 static void sm_handle_random_result_er(void *arg){ 3300 sm_persistent_keys_random_active = 0; 3301 if (arg){ 3302 // key generated, store in tlv 3303 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3304 log_info("Generated ER key. Store in TLV status: %d", status); 3305 UNUSED(status); 3306 } 3307 log_info_key("ER", sm_persistent_er); 3308 3309 // try load ir 3310 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3311 if (key_size == 16){ 3312 // ok, let's continue 3313 log_info("IR from TLV"); 3314 sm_handle_random_result_ir( NULL ); 3315 } else { 3316 // invalid, generate new random one 3317 sm_persistent_keys_random_active = 1; 3318 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3319 } 3320 } 3321 3322 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3323 3324 UNUSED(channel); // ok: there is no channel 3325 UNUSED(size); // ok: fixed format HCI events 3326 3327 sm_connection_t * sm_conn; 3328 hci_con_handle_t con_handle; 3329 uint8_t status; 3330 switch (packet_type) { 3331 3332 case HCI_EVENT_PACKET: 3333 switch (hci_event_packet_get_type(packet)) { 3334 3335 case BTSTACK_EVENT_STATE: 3336 // bt stack activated, get started 3337 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3338 log_info("HCI Working!"); 3339 3340 // setup IR/ER with TLV 3341 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3342 if (sm_tlv_impl){ 3343 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3344 if (key_size == 16){ 3345 // ok, let's continue 3346 log_info("ER from TLV"); 3347 sm_handle_random_result_er( NULL ); 3348 } else { 3349 // invalid, generate random one 3350 sm_persistent_keys_random_active = 1; 3351 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3352 } 3353 } else { 3354 sm_validate_er_ir(); 3355 dkg_state = DKG_CALC_IRK; 3356 3357 if (test_use_fixed_local_irk){ 3358 log_info_key("IRK", sm_persistent_irk); 3359 dkg_state = DKG_CALC_DHK; 3360 } 3361 } 3362 3363 // restart random address updates after power cycle 3364 gap_random_address_set_mode(gap_random_adress_type); 3365 } 3366 break; 3367 3368 case HCI_EVENT_LE_META: 3369 switch (packet[2]) { 3370 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3371 3372 log_info("sm: connected"); 3373 3374 if (packet[3]) return; // connection failed 3375 3376 con_handle = little_endian_read_16(packet, 4); 3377 sm_conn = sm_get_connection_for_handle(con_handle); 3378 if (!sm_conn) break; 3379 3380 sm_conn->sm_handle = con_handle; 3381 sm_conn->sm_role = packet[6]; 3382 sm_conn->sm_peer_addr_type = packet[7]; 3383 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3384 3385 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3386 3387 // reset security properties 3388 sm_conn->sm_connection_encrypted = 0; 3389 sm_conn->sm_connection_authenticated = 0; 3390 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3391 sm_conn->sm_le_db_index = -1; 3392 3393 // prepare CSRK lookup (does not involve setup) 3394 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3395 3396 // just connected -> everything else happens in sm_run() 3397 if (IS_RESPONDER(sm_conn->sm_role)){ 3398 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3399 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3400 if (sm_slave_request_security) { 3401 // request security if requested by app 3402 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3403 } else { 3404 // otherwise, wait for pairing request 3405 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3406 } 3407 } 3408 break; 3409 } else { 3410 // master 3411 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3412 } 3413 break; 3414 3415 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3416 con_handle = little_endian_read_16(packet, 3); 3417 sm_conn = sm_get_connection_for_handle(con_handle); 3418 if (!sm_conn) break; 3419 3420 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3421 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3422 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3423 break; 3424 } 3425 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3426 // PH2 SEND LTK as we need to exchange keys in PH3 3427 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3428 break; 3429 } 3430 3431 // store rand and ediv 3432 reverse_64(&packet[5], sm_conn->sm_local_rand); 3433 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3434 3435 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3436 // potentially stored LTK is from the master 3437 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 3438 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3439 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3440 break; 3441 } 3442 // additionally check if remote is in LE Device DB if requested 3443 switch(sm_conn->sm_irk_lookup_state){ 3444 case IRK_LOOKUP_FAILED: 3445 log_info("LTK Request: device not in device db"); 3446 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3447 break; 3448 case IRK_LOOKUP_SUCCEEDED: 3449 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3450 break; 3451 default: 3452 // wait for irk look doen 3453 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3454 break; 3455 } 3456 break; 3457 } 3458 3459 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3460 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3461 #else 3462 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3463 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3464 #endif 3465 break; 3466 3467 default: 3468 break; 3469 } 3470 break; 3471 3472 case HCI_EVENT_ENCRYPTION_CHANGE: 3473 con_handle = hci_event_encryption_change_get_connection_handle(packet); 3474 sm_conn = sm_get_connection_for_handle(con_handle); 3475 if (!sm_conn) break; 3476 3477 sm_conn->sm_connection_encrypted = hci_event_encryption_change_get_encryption_enabled(packet); 3478 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3479 sm_conn->sm_actual_encryption_key_size); 3480 log_info("event handler, state %u", sm_conn->sm_engine_state); 3481 3482 switch (sm_conn->sm_engine_state){ 3483 3484 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3485 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3486 if (sm_conn->sm_connection_encrypted) { 3487 status = ERROR_CODE_SUCCESS; 3488 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3489 } else { 3490 status = ERROR_CODE_AUTHENTICATION_FAILURE; 3491 // set state to 'TIMEOUT' to prevent further interaction with this 3492 // also, gap_reconnect_security_setup_active will return true 3493 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 3494 } 3495 3496 // emit re-encryption complete 3497 sm_notify_client_reencryption_complete(sm_conn, status); 3498 3499 // notify client, if pairing was requested before 3500 if (sm_conn->sm_pairing_requested){ 3501 sm_conn->sm_pairing_requested = 0; 3502 sm_notify_client_status_reason(sm_conn, status, 0); 3503 } 3504 3505 sm_done_for_handle(sm_conn->sm_handle); 3506 3507 // abort/disconnect on authentication failure 3508 if (status == ERROR_CODE_AUTHENTICATION_FAILURE){ 3509 // gap disconnect with authentication failure 3510 hci_disconnect_security_block(con_handle); 3511 } 3512 break; 3513 3514 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3515 if (!sm_conn->sm_connection_encrypted) break; 3516 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3517 if (IS_RESPONDER(sm_conn->sm_role)){ 3518 // slave 3519 if (setup->sm_use_secure_connections){ 3520 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3521 } else { 3522 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); 3523 } 3524 } else { 3525 // master 3526 if (sm_key_distribution_all_received(sm_conn)){ 3527 // skip receiving keys as there are none 3528 sm_key_distribution_handle_all_received(sm_conn); 3529 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); 3530 } else { 3531 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3532 } 3533 } 3534 break; 3535 default: 3536 break; 3537 } 3538 break; 3539 3540 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3541 con_handle = little_endian_read_16(packet, 3); 3542 sm_conn = sm_get_connection_for_handle(con_handle); 3543 if (!sm_conn) break; 3544 3545 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3546 log_info("event handler, state %u", sm_conn->sm_engine_state); 3547 // continue if part of initial pairing 3548 switch (sm_conn->sm_engine_state){ 3549 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3550 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3551 sm_done_for_handle(sm_conn->sm_handle); 3552 break; 3553 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3554 if (IS_RESPONDER(sm_conn->sm_role)){ 3555 // slave 3556 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); 3557 } else { 3558 // master 3559 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3560 } 3561 break; 3562 default: 3563 break; 3564 } 3565 break; 3566 3567 3568 case HCI_EVENT_DISCONNECTION_COMPLETE: 3569 con_handle = little_endian_read_16(packet, 3); 3570 sm_done_for_handle(con_handle); 3571 sm_conn = sm_get_connection_for_handle(con_handle); 3572 if (!sm_conn) break; 3573 3574 // delete stored bonding on disconnect with authentication failure in ph0 3575 if ((sm_conn->sm_role == 0u) 3576 && (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED) 3577 && (packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE)){ 3578 le_device_db_remove(sm_conn->sm_le_db_index); 3579 } 3580 3581 // pairing failed, if it was ongoing 3582 switch (sm_conn->sm_engine_state){ 3583 case SM_GENERAL_IDLE: 3584 case SM_INITIATOR_CONNECTED: 3585 case SM_RESPONDER_IDLE: 3586 break; 3587 default: 3588 sm_notify_client_status_reason(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3589 break; 3590 } 3591 3592 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3593 sm_conn->sm_handle = 0; 3594 break; 3595 3596 case HCI_EVENT_COMMAND_COMPLETE: 3597 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3598 // set local addr for le device db 3599 bd_addr_t addr; 3600 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3601 le_device_db_set_local_bd_addr(addr); 3602 } 3603 break; 3604 default: 3605 break; 3606 } 3607 break; 3608 default: 3609 break; 3610 } 3611 3612 sm_run(); 3613 } 3614 3615 static inline int sm_calc_actual_encryption_key_size(int other){ 3616 if (other < sm_min_encryption_key_size) return 0; 3617 if (other < sm_max_encryption_key_size) return other; 3618 return sm_max_encryption_key_size; 3619 } 3620 3621 3622 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3623 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3624 switch (method){ 3625 case JUST_WORKS: 3626 case NUMERIC_COMPARISON: 3627 return 1; 3628 default: 3629 return 0; 3630 } 3631 } 3632 // responder 3633 3634 static int sm_passkey_used(stk_generation_method_t method){ 3635 switch (method){ 3636 case PK_RESP_INPUT: 3637 return 1; 3638 default: 3639 return 0; 3640 } 3641 } 3642 3643 static int sm_passkey_entry(stk_generation_method_t method){ 3644 switch (method){ 3645 case PK_RESP_INPUT: 3646 case PK_INIT_INPUT: 3647 case PK_BOTH_INPUT: 3648 return 1; 3649 default: 3650 return 0; 3651 } 3652 } 3653 3654 #endif 3655 3656 /** 3657 * @return ok 3658 */ 3659 static int sm_validate_stk_generation_method(void){ 3660 // check if STK generation method is acceptable by client 3661 switch (setup->sm_stk_generation_method){ 3662 case JUST_WORKS: 3663 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 3664 case PK_RESP_INPUT: 3665 case PK_INIT_INPUT: 3666 case PK_BOTH_INPUT: 3667 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 3668 case OOB: 3669 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 3670 case NUMERIC_COMPARISON: 3671 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 3672 default: 3673 return 0; 3674 } 3675 } 3676 3677 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3678 3679 // size of complete sm_pdu used to validate input 3680 static const uint8_t sm_pdu_size[] = { 3681 0, // 0x00 invalid opcode 3682 7, // 0x01 pairing request 3683 7, // 0x02 pairing response 3684 17, // 0x03 pairing confirm 3685 17, // 0x04 pairing random 3686 2, // 0x05 pairing failed 3687 17, // 0x06 encryption information 3688 11, // 0x07 master identification 3689 17, // 0x08 identification information 3690 8, // 0x09 identify address information 3691 17, // 0x0a signing information 3692 2, // 0x0b security request 3693 65, // 0x0c pairing public key 3694 17, // 0x0d pairing dhk check 3695 2, // 0x0e keypress notification 3696 }; 3697 3698 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 3699 sm_run(); 3700 } 3701 3702 if (packet_type != SM_DATA_PACKET) return; 3703 if (size == 0u) return; 3704 3705 uint8_t sm_pdu_code = packet[0]; 3706 3707 // validate pdu size 3708 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3709 if (sm_pdu_size[sm_pdu_code] != size) return; 3710 3711 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3712 if (!sm_conn) return; 3713 3714 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3715 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3716 sm_done_for_handle(con_handle); 3717 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3718 return; 3719 } 3720 3721 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3722 3723 int err; 3724 UNUSED(err); 3725 3726 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3727 uint8_t buffer[5]; 3728 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3729 buffer[1] = 3; 3730 little_endian_store_16(buffer, 2, con_handle); 3731 buffer[4] = packet[1]; 3732 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3733 return; 3734 } 3735 3736 switch (sm_conn->sm_engine_state){ 3737 3738 // a sm timeout requires a new physical connection 3739 case SM_GENERAL_TIMEOUT: 3740 return; 3741 3742 #ifdef ENABLE_LE_CENTRAL 3743 3744 // Initiator 3745 case SM_INITIATOR_CONNECTED: 3746 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3747 sm_pdu_received_in_wrong_state(sm_conn); 3748 break; 3749 } 3750 3751 // IRK complete? 3752 int have_ltk; 3753 uint8_t ltk[16]; 3754 switch (sm_conn->sm_irk_lookup_state){ 3755 case IRK_LOOKUP_FAILED: 3756 // start pairing 3757 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3758 break; 3759 case IRK_LOOKUP_SUCCEEDED: 3760 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 3761 have_ltk = !sm_is_null_key(ltk); 3762 log_info("central: security request - have_ltk %u", have_ltk); 3763 if (have_ltk){ 3764 // start re-encrypt 3765 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3766 } else { 3767 // start pairing 3768 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3769 } 3770 break; 3771 default: 3772 // otherwise, store security request 3773 sm_conn->sm_security_request_received = 1; 3774 break; 3775 } 3776 break; 3777 3778 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3779 // Core 5, Vol 3, Part H, 2.4.6: 3780 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3781 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3782 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3783 log_info("Ignoring Security Request"); 3784 break; 3785 } 3786 3787 // all other pdus are incorrect 3788 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3789 sm_pdu_received_in_wrong_state(sm_conn); 3790 break; 3791 } 3792 3793 // store pairing request 3794 (void)memcpy(&setup->sm_s_pres, packet, 3795 sizeof(sm_pairing_packet_t)); 3796 err = sm_stk_generation_init(sm_conn); 3797 3798 #ifdef ENABLE_TESTING_SUPPORT 3799 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3800 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3801 err = test_pairing_failure; 3802 } 3803 #endif 3804 3805 if (err){ 3806 setup->sm_pairing_failed_reason = err; 3807 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3808 break; 3809 } 3810 3811 // generate random number first, if we need to show passkey 3812 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3813 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); 3814 break; 3815 } 3816 3817 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3818 if (setup->sm_use_secure_connections){ 3819 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3820 if (setup->sm_stk_generation_method == JUST_WORKS){ 3821 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3822 sm_trigger_user_response(sm_conn); 3823 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3824 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3825 } 3826 } else { 3827 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3828 } 3829 break; 3830 } 3831 #endif 3832 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3833 sm_trigger_user_response(sm_conn); 3834 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3835 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3836 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); 3837 } 3838 break; 3839 3840 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3841 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3842 sm_pdu_received_in_wrong_state(sm_conn); 3843 break; 3844 } 3845 3846 // store s_confirm 3847 reverse_128(&packet[1], setup->sm_peer_confirm); 3848 3849 #ifdef ENABLE_TESTING_SUPPORT 3850 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3851 log_info("testing_support: reset confirm value"); 3852 memset(setup->sm_peer_confirm, 0, 16); 3853 } 3854 #endif 3855 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3856 break; 3857 3858 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3859 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3860 sm_pdu_received_in_wrong_state(sm_conn); 3861 break;; 3862 } 3863 3864 // received random value 3865 reverse_128(&packet[1], setup->sm_peer_random); 3866 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3867 break; 3868 #endif 3869 3870 #ifdef ENABLE_LE_PERIPHERAL 3871 // Responder 3872 case SM_RESPONDER_IDLE: 3873 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3874 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3875 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3876 sm_pdu_received_in_wrong_state(sm_conn); 3877 break;; 3878 } 3879 3880 // store pairing request 3881 (void)memcpy(&sm_conn->sm_m_preq, packet, 3882 sizeof(sm_pairing_packet_t)); 3883 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3884 break; 3885 #endif 3886 3887 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3888 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3889 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3890 sm_pdu_received_in_wrong_state(sm_conn); 3891 break; 3892 } 3893 3894 // store public key for DH Key calculation 3895 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3896 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3897 3898 // validate public key 3899 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 3900 if (err){ 3901 log_error("sm: peer public key invalid %x", err); 3902 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 3903 break; 3904 } 3905 3906 // start calculating dhkey 3907 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); 3908 3909 3910 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3911 if (IS_RESPONDER(sm_conn->sm_role)){ 3912 // responder 3913 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3914 } else { 3915 // initiator 3916 // stk generation method 3917 // passkey entry: notify app to show passkey or to request passkey 3918 switch (setup->sm_stk_generation_method){ 3919 case JUST_WORKS: 3920 case NUMERIC_COMPARISON: 3921 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3922 break; 3923 case PK_RESP_INPUT: 3924 sm_sc_start_calculating_local_confirm(sm_conn); 3925 break; 3926 case PK_INIT_INPUT: 3927 case PK_BOTH_INPUT: 3928 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3929 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3930 break; 3931 } 3932 sm_sc_start_calculating_local_confirm(sm_conn); 3933 break; 3934 case OOB: 3935 // generate Nx 3936 log_info("Generate Na"); 3937 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); 3938 break; 3939 default: 3940 btstack_assert(false); 3941 break; 3942 } 3943 } 3944 break; 3945 3946 case SM_SC_W4_CONFIRMATION: 3947 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3948 sm_pdu_received_in_wrong_state(sm_conn); 3949 break; 3950 } 3951 // received confirm value 3952 reverse_128(&packet[1], setup->sm_peer_confirm); 3953 3954 #ifdef ENABLE_TESTING_SUPPORT 3955 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3956 log_info("testing_support: reset confirm value"); 3957 memset(setup->sm_peer_confirm, 0, 16); 3958 } 3959 #endif 3960 if (IS_RESPONDER(sm_conn->sm_role)){ 3961 // responder 3962 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3963 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3964 // still waiting for passkey 3965 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3966 break; 3967 } 3968 } 3969 sm_sc_start_calculating_local_confirm(sm_conn); 3970 } else { 3971 // initiator 3972 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3973 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); 3974 } else { 3975 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3976 } 3977 } 3978 break; 3979 3980 case SM_SC_W4_PAIRING_RANDOM: 3981 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3982 sm_pdu_received_in_wrong_state(sm_conn); 3983 break; 3984 } 3985 3986 // received random value 3987 reverse_128(&packet[1], setup->sm_peer_nonce); 3988 3989 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3990 // only check for JUST WORK/NC in initiator role OR passkey entry 3991 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 3992 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 3993 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 3994 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 3995 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 3996 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3997 break; 3998 } 3999 4000 // OOB 4001 if (setup->sm_stk_generation_method == OOB){ 4002 4003 // setup local random, set to zero if remote did not receive our data 4004 log_info("Received nonce, setup local random ra/rb for dhkey check"); 4005 if (IS_RESPONDER(sm_conn->sm_role)){ 4006 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u){ 4007 log_info("Reset rb as A does not have OOB data"); 4008 memset(setup->sm_rb, 0, 16); 4009 } else { 4010 (void)memcpy(setup->sm_rb, sm_sc_oob_random, 16); 4011 log_info("Use stored rb"); 4012 log_info_hexdump(setup->sm_rb, 16); 4013 } 4014 } else { 4015 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 4016 log_info("Reset ra as B does not have OOB data"); 4017 memset(setup->sm_ra, 0, 16); 4018 } else { 4019 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 4020 log_info("Use stored ra"); 4021 log_info_hexdump(setup->sm_ra, 16); 4022 } 4023 } 4024 4025 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 4026 if (setup->sm_have_oob_data){ 4027 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 4028 break; 4029 } 4030 } 4031 4032 // TODO: we only get here for Responder role with JW/NC 4033 sm_sc_state_after_receiving_random(sm_conn); 4034 break; 4035 4036 case SM_SC_W2_CALCULATE_G2: 4037 case SM_SC_W4_CALCULATE_G2: 4038 case SM_SC_W4_CALCULATE_DHKEY: 4039 case SM_SC_W2_CALCULATE_F5_SALT: 4040 case SM_SC_W4_CALCULATE_F5_SALT: 4041 case SM_SC_W2_CALCULATE_F5_MACKEY: 4042 case SM_SC_W4_CALCULATE_F5_MACKEY: 4043 case SM_SC_W2_CALCULATE_F5_LTK: 4044 case SM_SC_W4_CALCULATE_F5_LTK: 4045 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 4046 case SM_SC_W4_DHKEY_CHECK_COMMAND: 4047 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 4048 case SM_SC_W4_USER_RESPONSE: 4049 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 4050 sm_pdu_received_in_wrong_state(sm_conn); 4051 break; 4052 } 4053 // store DHKey Check 4054 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 4055 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 4056 4057 // have we been only waiting for dhkey check command? 4058 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 4059 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 4060 } 4061 break; 4062 #endif 4063 4064 #ifdef ENABLE_LE_PERIPHERAL 4065 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 4066 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 4067 sm_pdu_received_in_wrong_state(sm_conn); 4068 break; 4069 } 4070 4071 // received confirm value 4072 reverse_128(&packet[1], setup->sm_peer_confirm); 4073 4074 #ifdef ENABLE_TESTING_SUPPORT 4075 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 4076 log_info("testing_support: reset confirm value"); 4077 memset(setup->sm_peer_confirm, 0, 16); 4078 } 4079 #endif 4080 // notify client to hide shown passkey 4081 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 4082 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 4083 } 4084 4085 // handle user cancel pairing? 4086 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 4087 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 4088 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 4089 break; 4090 } 4091 4092 // wait for user action? 4093 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 4094 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4095 break; 4096 } 4097 4098 // calculate and send local_confirm 4099 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); 4100 break; 4101 4102 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 4103 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4104 sm_pdu_received_in_wrong_state(sm_conn); 4105 break;; 4106 } 4107 4108 // received random value 4109 reverse_128(&packet[1], setup->sm_peer_random); 4110 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4111 break; 4112 #endif 4113 4114 case SM_PH3_RECEIVE_KEYS: 4115 switch(sm_pdu_code){ 4116 case SM_CODE_ENCRYPTION_INFORMATION: 4117 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 4118 reverse_128(&packet[1], setup->sm_peer_ltk); 4119 break; 4120 4121 case SM_CODE_MASTER_IDENTIFICATION: 4122 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 4123 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 4124 reverse_64(&packet[3], setup->sm_peer_rand); 4125 break; 4126 4127 case SM_CODE_IDENTITY_INFORMATION: 4128 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4129 reverse_128(&packet[1], setup->sm_peer_irk); 4130 break; 4131 4132 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4133 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4134 setup->sm_peer_addr_type = packet[1]; 4135 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4136 break; 4137 4138 case SM_CODE_SIGNING_INFORMATION: 4139 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4140 reverse_128(&packet[1], setup->sm_peer_csrk); 4141 break; 4142 default: 4143 // Unexpected PDU 4144 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4145 break; 4146 } 4147 // done with key distribution? 4148 if (sm_key_distribution_all_received(sm_conn)){ 4149 4150 sm_key_distribution_handle_all_received(sm_conn); 4151 4152 if (IS_RESPONDER(sm_conn->sm_role)){ 4153 if (sm_ctkd_from_le(sm_conn)){ 4154 bool use_h7 = (sm_pairing_packet_get_auth_req(setup->sm_m_preq) & sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_CT2) != 0; 4155 sm_conn->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 4156 } else { 4157 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 4158 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 4159 sm_done_for_handle(sm_conn->sm_handle); 4160 } 4161 } else { 4162 if (setup->sm_use_secure_connections){ 4163 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4164 } else { 4165 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); 4166 } 4167 } 4168 } 4169 break; 4170 default: 4171 // Unexpected PDU 4172 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4173 break; 4174 } 4175 4176 // try to send next pdu 4177 sm_trigger_run(); 4178 } 4179 4180 // Security Manager Client API 4181 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 4182 sm_get_oob_data = get_oob_data_callback; 4183 } 4184 4185 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)){ 4186 sm_get_sc_oob_data = get_sc_oob_data_callback; 4187 } 4188 4189 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4190 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4191 } 4192 4193 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 4194 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 4195 } 4196 4197 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 4198 sm_min_encryption_key_size = min_size; 4199 sm_max_encryption_key_size = max_size; 4200 } 4201 4202 void sm_set_authentication_requirements(uint8_t auth_req){ 4203 #ifndef ENABLE_LE_SECURE_CONNECTIONS 4204 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 4205 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 4206 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 4207 } 4208 #endif 4209 sm_auth_req = auth_req; 4210 } 4211 4212 void sm_set_io_capabilities(io_capability_t io_capability){ 4213 sm_io_capabilities = io_capability; 4214 } 4215 4216 #ifdef ENABLE_LE_PERIPHERAL 4217 void sm_set_request_security(int enable){ 4218 sm_slave_request_security = enable; 4219 } 4220 #endif 4221 4222 void sm_set_er(sm_key_t er){ 4223 (void)memcpy(sm_persistent_er, er, 16); 4224 } 4225 4226 void sm_set_ir(sm_key_t ir){ 4227 (void)memcpy(sm_persistent_ir, ir, 16); 4228 } 4229 4230 // Testing support only 4231 void sm_test_set_irk(sm_key_t irk){ 4232 (void)memcpy(sm_persistent_irk, irk, 16); 4233 dkg_state = DKG_CALC_DHK; 4234 test_use_fixed_local_irk = true; 4235 } 4236 4237 void sm_test_use_fixed_local_csrk(void){ 4238 test_use_fixed_local_csrk = true; 4239 } 4240 4241 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4242 static void sm_ec_generated(void * arg){ 4243 UNUSED(arg); 4244 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4245 // trigger pairing if pending for ec key 4246 sm_trigger_run(); 4247 } 4248 static void sm_ec_generate_new_key(void){ 4249 log_info("sm: generate new ec key"); 4250 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 4251 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 4252 } 4253 #endif 4254 4255 #ifdef ENABLE_TESTING_SUPPORT 4256 void sm_test_set_pairing_failure(int reason){ 4257 test_pairing_failure = reason; 4258 } 4259 #endif 4260 4261 void sm_init(void){ 4262 // set default ER and IR values (should be unique - set by app or sm later using TLV) 4263 sm_er_ir_set_default(); 4264 4265 // defaults 4266 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4267 | SM_STK_GENERATION_METHOD_OOB 4268 | SM_STK_GENERATION_METHOD_PASSKEY 4269 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4270 4271 sm_max_encryption_key_size = 16; 4272 sm_min_encryption_key_size = 7; 4273 4274 sm_fixed_passkey_in_display_role = 0xffffffff; 4275 sm_reconstruct_ltk_without_le_device_db_entry = 1; 4276 4277 #ifdef USE_CMAC_ENGINE 4278 sm_cmac_active = 0; 4279 #endif 4280 dkg_state = DKG_W4_WORKING; 4281 rau_state = RAU_IDLE; 4282 sm_aes128_state = SM_AES128_IDLE; 4283 sm_address_resolution_test = -1; // no private address to resolve yet 4284 sm_address_resolution_ah_calculation_active = 0; 4285 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4286 sm_address_resolution_general_queue = NULL; 4287 4288 gap_random_adress_update_period = 15 * 60 * 1000L; 4289 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4290 4291 test_use_fixed_local_csrk = false; 4292 4293 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 4294 4295 // register for HCI Events from HCI 4296 hci_event_callback_registration.callback = &sm_event_packet_handler; 4297 hci_add_event_handler(&hci_event_callback_registration); 4298 4299 // 4300 btstack_crypto_init(); 4301 4302 // init le_device_db 4303 le_device_db_init(); 4304 4305 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4306 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4307 4308 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4309 sm_ec_generate_new_key(); 4310 #endif 4311 } 4312 4313 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4314 sm_fixed_passkey_in_display_role = passkey; 4315 } 4316 4317 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4318 sm_reconstruct_ltk_without_le_device_db_entry = allow; 4319 } 4320 4321 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4322 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4323 if (!hci_con) return NULL; 4324 return &hci_con->sm_connection; 4325 } 4326 4327 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 4328 switch (sm_conn->sm_engine_state){ 4329 case SM_GENERAL_IDLE: 4330 case SM_RESPONDER_IDLE: 4331 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4332 sm_trigger_run(); 4333 break; 4334 default: 4335 break; 4336 } 4337 } 4338 4339 /** 4340 * @brief Trigger Security Request 4341 */ 4342 void sm_send_security_request(hci_con_handle_t con_handle){ 4343 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4344 if (!sm_conn) return; 4345 sm_send_security_request_for_connection(sm_conn); 4346 } 4347 4348 // request pairing 4349 void sm_request_pairing(hci_con_handle_t con_handle){ 4350 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4351 if (!sm_conn) return; // wrong connection 4352 4353 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4354 if (IS_RESPONDER(sm_conn->sm_role)){ 4355 sm_send_security_request_for_connection(sm_conn); 4356 } else { 4357 // used as a trigger to start central/master/initiator security procedures 4358 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 4359 uint8_t ltk[16]; 4360 bool have_ltk; 4361 switch (sm_conn->sm_irk_lookup_state){ 4362 case IRK_LOOKUP_SUCCEEDED: 4363 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4364 have_ltk = !sm_is_null_key(ltk); 4365 log_info("have ltk %u", have_ltk); 4366 if (have_ltk){ 4367 sm_conn->sm_pairing_requested = 1; 4368 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 4369 sm_reencryption_started(sm_conn); 4370 break; 4371 } 4372 /* fall through */ 4373 4374 case IRK_LOOKUP_FAILED: 4375 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4376 break; 4377 default: 4378 log_info("irk lookup pending"); 4379 sm_conn->sm_pairing_requested = 1; 4380 break; 4381 } 4382 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 4383 sm_conn->sm_pairing_requested = 1; 4384 } 4385 } 4386 sm_trigger_run(); 4387 } 4388 4389 // called by client app on authorization request 4390 void sm_authorization_decline(hci_con_handle_t con_handle){ 4391 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4392 if (!sm_conn) return; // wrong connection 4393 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4394 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4395 } 4396 4397 void sm_authorization_grant(hci_con_handle_t con_handle){ 4398 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4399 if (!sm_conn) return; // wrong connection 4400 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4401 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4402 } 4403 4404 // GAP Bonding API 4405 4406 void sm_bonding_decline(hci_con_handle_t con_handle){ 4407 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4408 if (!sm_conn) return; // wrong connection 4409 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4410 log_info("decline, state %u", sm_conn->sm_engine_state); 4411 switch(sm_conn->sm_engine_state){ 4412 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4413 case SM_SC_W4_USER_RESPONSE: 4414 case SM_SC_W4_CONFIRMATION: 4415 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4416 #endif 4417 case SM_PH1_W4_USER_RESPONSE: 4418 switch (setup->sm_stk_generation_method){ 4419 case PK_RESP_INPUT: 4420 case PK_INIT_INPUT: 4421 case PK_BOTH_INPUT: 4422 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4423 break; 4424 case NUMERIC_COMPARISON: 4425 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4426 break; 4427 case JUST_WORKS: 4428 case OOB: 4429 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4430 break; 4431 default: 4432 btstack_assert(false); 4433 break; 4434 } 4435 break; 4436 default: 4437 break; 4438 } 4439 sm_trigger_run(); 4440 } 4441 4442 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4443 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4444 if (!sm_conn) return; // wrong connection 4445 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4446 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4447 if (setup->sm_use_secure_connections){ 4448 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4449 } else { 4450 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); 4451 } 4452 } 4453 4454 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4455 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4456 sm_sc_prepare_dhkey_check(sm_conn); 4457 } 4458 #endif 4459 4460 sm_trigger_run(); 4461 } 4462 4463 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4464 // for now, it's the same 4465 sm_just_works_confirm(con_handle); 4466 } 4467 4468 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4469 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4470 if (!sm_conn) return; // wrong connection 4471 sm_reset_tk(); 4472 big_endian_store_32(setup->sm_tk, 12, passkey); 4473 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4474 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4475 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); 4476 } 4477 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4478 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 4479 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 4480 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4481 sm_sc_start_calculating_local_confirm(sm_conn); 4482 } 4483 #endif 4484 sm_trigger_run(); 4485 } 4486 4487 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4488 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4489 if (!sm_conn) return; // wrong connection 4490 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4491 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4492 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 4493 switch (action){ 4494 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4495 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4496 flags |= (1u << action); 4497 break; 4498 case SM_KEYPRESS_PASSKEY_CLEARED: 4499 // clear counter, keypress & erased flags + set passkey cleared 4500 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 4501 break; 4502 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4503 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4504 // erase actions queued 4505 num_actions--; 4506 if (num_actions == 0u){ 4507 // clear counter, keypress & erased flags 4508 flags &= 0x19u; 4509 } 4510 break; 4511 } 4512 num_actions++; 4513 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4514 break; 4515 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4516 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4517 // enter actions queued 4518 num_actions--; 4519 if (num_actions == 0u){ 4520 // clear counter, keypress & erased flags 4521 flags &= 0x19u; 4522 } 4523 break; 4524 } 4525 num_actions++; 4526 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4527 break; 4528 default: 4529 break; 4530 } 4531 setup->sm_keypress_notification = (num_actions << 5) | flags; 4532 sm_trigger_run(); 4533 } 4534 4535 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4536 static void sm_handle_random_result_oob(void * arg){ 4537 UNUSED(arg); 4538 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4539 sm_trigger_run(); 4540 } 4541 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4542 4543 static btstack_crypto_random_t sm_crypto_random_oob_request; 4544 4545 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4546 sm_sc_oob_callback = callback; 4547 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4548 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4549 return 0; 4550 } 4551 #endif 4552 4553 /** 4554 * @brief Get Identity Resolving state 4555 * @param con_handle 4556 * @return irk_lookup_state_t 4557 */ 4558 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 4559 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4560 if (!sm_conn) return IRK_LOOKUP_IDLE; 4561 return sm_conn->sm_irk_lookup_state; 4562 } 4563 4564 /** 4565 * @brief Identify device in LE Device DB 4566 * @param handle 4567 * @returns index from le_device_db or -1 if not found/identified 4568 */ 4569 int sm_le_device_index(hci_con_handle_t con_handle ){ 4570 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4571 if (!sm_conn) return -1; 4572 return sm_conn->sm_le_db_index; 4573 } 4574 4575 static int gap_random_address_type_requires_updates(void){ 4576 switch (gap_random_adress_type){ 4577 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4578 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4579 return 0; 4580 default: 4581 return 1; 4582 } 4583 } 4584 4585 static uint8_t own_address_type(void){ 4586 switch (gap_random_adress_type){ 4587 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4588 return BD_ADDR_TYPE_LE_PUBLIC; 4589 default: 4590 return BD_ADDR_TYPE_LE_RANDOM; 4591 } 4592 } 4593 4594 // GAP LE API 4595 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4596 gap_random_address_update_stop(); 4597 gap_random_adress_type = random_address_type; 4598 hci_le_set_own_address_type(own_address_type()); 4599 if (!gap_random_address_type_requires_updates()) return; 4600 gap_random_address_update_start(); 4601 gap_random_address_trigger(); 4602 } 4603 4604 gap_random_address_type_t gap_random_address_get_mode(void){ 4605 return gap_random_adress_type; 4606 } 4607 4608 void gap_random_address_set_update_period(int period_ms){ 4609 gap_random_adress_update_period = period_ms; 4610 if (!gap_random_address_type_requires_updates()) return; 4611 gap_random_address_update_stop(); 4612 gap_random_address_update_start(); 4613 } 4614 4615 void gap_random_address_set(const bd_addr_t addr){ 4616 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4617 (void)memcpy(sm_random_address, addr, 6); 4618 rau_state = RAU_SET_ADDRESS; 4619 sm_trigger_run(); 4620 } 4621 4622 #ifdef ENABLE_LE_PERIPHERAL 4623 /* 4624 * @brief Set Advertisement Paramters 4625 * @param adv_int_min 4626 * @param adv_int_max 4627 * @param adv_type 4628 * @param direct_address_type 4629 * @param direct_address 4630 * @param channel_map 4631 * @param filter_policy 4632 * 4633 * @note own_address_type is used from gap_random_address_set_mode 4634 */ 4635 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4636 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4637 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4638 direct_address_typ, direct_address, channel_map, filter_policy); 4639 } 4640 #endif 4641 4642 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4643 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4644 // wrong connection 4645 if (!sm_conn) return 0; 4646 // already encrypted 4647 if (sm_conn->sm_connection_encrypted) return 0; 4648 // only central can re-encrypt 4649 if (sm_conn->sm_role == HCI_ROLE_SLAVE) return 0; 4650 // irk status? 4651 switch(sm_conn->sm_irk_lookup_state){ 4652 case IRK_LOOKUP_FAILED: 4653 // done, cannot setup encryption 4654 return 0; 4655 case IRK_LOOKUP_SUCCEEDED: 4656 break; 4657 default: 4658 // IR Lookup pending 4659 return 1; 4660 } 4661 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset 4662 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4663 } 4664 4665 void sm_set_secure_connections_only_mode(bool enable){ 4666 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4667 sm_sc_only_mode = enable; 4668 #else 4669 // SC Only mode not possible without support for SC 4670 btstack_assert(enable == false); 4671 #endif 4672 } 4673 4674 const uint8_t * gap_get_persistent_irk(void){ 4675 return sm_persistent_irk; 4676 } 4677