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_SUCEEDED, 153 ADDRESS_RESOLUTION_FAILED, 154 } address_resolution_event_t; 155 156 typedef enum { 157 EC_KEY_GENERATION_IDLE, 158 EC_KEY_GENERATION_ACTIVE, 159 EC_KEY_GENERATION_DONE, 160 } ec_key_generation_state_t; 161 162 typedef enum { 163 SM_STATE_VAR_DHKEY_NEEDED = 1 << 0, 164 SM_STATE_VAR_DHKEY_CALCULATED = 1 << 1, 165 SM_STATE_VAR_DHKEY_COMMAND_RECEIVED = 1 << 2, 166 } sm_state_var_t; 167 168 typedef enum { 169 SM_SC_OOB_IDLE, 170 SM_SC_OOB_W4_RANDOM, 171 SM_SC_OOB_W2_CALC_CONFIRM, 172 SM_SC_OOB_W4_CONFIRM, 173 } sm_sc_oob_state_t; 174 175 typedef uint8_t sm_key24_t[3]; 176 typedef uint8_t sm_key56_t[7]; 177 typedef uint8_t sm_key256_t[32]; 178 179 // 180 // GLOBAL DATA 181 // 182 183 static bool test_use_fixed_local_csrk; 184 static bool test_use_fixed_local_irk; 185 186 #ifdef ENABLE_TESTING_SUPPORT 187 static uint8_t test_pairing_failure; 188 #endif 189 190 // configuration 191 static uint8_t sm_accepted_stk_generation_methods; 192 static uint8_t sm_max_encryption_key_size; 193 static uint8_t sm_min_encryption_key_size; 194 static uint8_t sm_auth_req = 0; 195 static uint8_t sm_io_capabilities = IO_CAPABILITY_NO_INPUT_NO_OUTPUT; 196 static uint8_t sm_slave_request_security; 197 static uint32_t sm_fixed_passkey_in_display_role; 198 static uint8_t sm_reconstruct_ltk_without_le_device_db_entry; 199 200 #ifdef ENABLE_LE_SECURE_CONNECTIONS 201 static bool sm_sc_only_mode; 202 static uint8_t sm_sc_oob_random[16]; 203 static void (*sm_sc_oob_callback)(const uint8_t * confirm_value, const uint8_t * random_value); 204 static sm_sc_oob_state_t sm_sc_oob_state; 205 #endif 206 207 208 static uint8_t sm_persistent_keys_random_active; 209 static const btstack_tlv_t * sm_tlv_impl; 210 static void * sm_tlv_context; 211 212 // Security Manager Master Keys, please use sm_set_er(er) and sm_set_ir(ir) with your own 128 bit random values 213 static sm_key_t sm_persistent_er; 214 static sm_key_t sm_persistent_ir; 215 216 // derived from sm_persistent_ir 217 static sm_key_t sm_persistent_dhk; 218 static sm_key_t sm_persistent_irk; 219 static derived_key_generation_t dkg_state; 220 221 // derived from sm_persistent_er 222 // .. 223 224 // random address update 225 static random_address_update_t rau_state; 226 static bd_addr_t sm_random_address; 227 228 #ifdef USE_CMAC_ENGINE 229 // CMAC Calculation: General 230 static btstack_crypto_aes128_cmac_t sm_cmac_request; 231 static void (*sm_cmac_done_callback)(uint8_t hash[8]); 232 static uint8_t sm_cmac_active; 233 static uint8_t sm_cmac_hash[16]; 234 #endif 235 236 // CMAC for ATT Signed Writes 237 #ifdef ENABLE_LE_SIGNED_WRITE 238 static uint16_t sm_cmac_signed_write_message_len; 239 static uint8_t sm_cmac_signed_write_header[3]; 240 static const uint8_t * sm_cmac_signed_write_message; 241 static uint8_t sm_cmac_signed_write_sign_counter[4]; 242 #endif 243 244 // CMAC for Secure Connection functions 245 #ifdef ENABLE_LE_SECURE_CONNECTIONS 246 static sm_connection_t * sm_cmac_connection; 247 static uint8_t sm_cmac_sc_buffer[80]; 248 #endif 249 250 // resolvable private address lookup / CSRK calculation 251 static int sm_address_resolution_test; 252 static int sm_address_resolution_ah_calculation_active; 253 static uint8_t sm_address_resolution_addr_type; 254 static bd_addr_t sm_address_resolution_address; 255 static void * sm_address_resolution_context; 256 static address_resolution_mode_t sm_address_resolution_mode; 257 static btstack_linked_list_t sm_address_resolution_general_queue; 258 259 // aes128 crypto engine. 260 static sm_aes128_state_t sm_aes128_state; 261 262 // crypto 263 static btstack_crypto_random_t sm_crypto_random_request; 264 static btstack_crypto_aes128_t sm_crypto_aes128_request; 265 #ifdef ENABLE_LE_SECURE_CONNECTIONS 266 static btstack_crypto_ecc_p256_t sm_crypto_ecc_p256_request; 267 #endif 268 269 // temp storage for random data 270 static uint8_t sm_random_data[8]; 271 static uint8_t sm_aes128_key[16]; 272 static uint8_t sm_aes128_plaintext[16]; 273 static uint8_t sm_aes128_ciphertext[16]; 274 275 // to receive hci events 276 static btstack_packet_callback_registration_t hci_event_callback_registration; 277 278 /* to dispatch sm event */ 279 static btstack_linked_list_t sm_event_handlers; 280 281 /* to schedule calls to sm_run */ 282 static btstack_timer_source_t sm_run_timer; 283 284 // LE Secure Connections 285 #ifdef ENABLE_LE_SECURE_CONNECTIONS 286 static ec_key_generation_state_t ec_key_generation_state; 287 static uint8_t ec_q[64]; 288 #endif 289 290 // 291 // Volume 3, Part H, Chapter 24 292 // "Security shall be initiated by the Security Manager in the device in the master role. 293 // The device in the slave role shall be the responding device." 294 // -> master := initiator, slave := responder 295 // 296 297 // data needed for security setup 298 typedef struct sm_setup_context { 299 300 btstack_timer_source_t sm_timeout; 301 302 // used in all phases 303 uint8_t sm_pairing_failed_reason; 304 305 // user response, (Phase 1 and/or 2) 306 uint8_t sm_user_response; 307 uint8_t sm_keypress_notification; // bitmap: passkey started, digit entered, digit erased, passkey cleared, passkey complete, 3 bit count 308 309 // defines which keys will be send after connection is encrypted - calculated during Phase 1, used Phase 3 310 uint8_t sm_key_distribution_send_set; 311 uint8_t sm_key_distribution_sent_set; 312 uint8_t sm_key_distribution_received_set; 313 314 // Phase 2 (Pairing over SMP) 315 stk_generation_method_t sm_stk_generation_method; 316 sm_key_t sm_tk; 317 uint8_t sm_have_oob_data; 318 uint8_t sm_use_secure_connections; 319 320 sm_key_t sm_c1_t3_value; // c1 calculation 321 sm_pairing_packet_t sm_m_preq; // pairing request - needed only for c1 322 sm_pairing_packet_t sm_s_pres; // pairing response - needed only for c1 323 sm_key_t sm_local_random; 324 sm_key_t sm_local_confirm; 325 sm_key_t sm_peer_random; 326 sm_key_t sm_peer_confirm; 327 uint8_t sm_m_addr_type; // address and type can be removed 328 uint8_t sm_s_addr_type; // '' 329 bd_addr_t sm_m_address; // '' 330 bd_addr_t sm_s_address; // '' 331 sm_key_t sm_ltk; 332 333 uint8_t sm_state_vars; 334 #ifdef ENABLE_LE_SECURE_CONNECTIONS 335 uint8_t sm_peer_q[64]; // also stores random for EC key generation during init 336 sm_key_t sm_peer_nonce; // might be combined with sm_peer_random 337 sm_key_t sm_local_nonce; // might be combined with sm_local_random 338 uint8_t sm_dhkey[32]; 339 sm_key_t sm_peer_dhkey_check; 340 sm_key_t sm_local_dhkey_check; 341 sm_key_t sm_ra; 342 sm_key_t sm_rb; 343 sm_key_t sm_t; // used for f5 and h6 344 sm_key_t sm_mackey; 345 uint8_t sm_passkey_bit; // also stores number of generated random bytes for EC key generation 346 #endif 347 348 // Phase 3 349 350 // key distribution, we generate 351 uint16_t sm_local_y; 352 uint16_t sm_local_div; 353 uint16_t sm_local_ediv; 354 uint8_t sm_local_rand[8]; 355 sm_key_t sm_local_ltk; 356 sm_key_t sm_local_csrk; 357 sm_key_t sm_local_irk; 358 // sm_local_address/addr_type not needed 359 360 // key distribution, received from peer 361 uint16_t sm_peer_y; 362 uint16_t sm_peer_div; 363 uint16_t sm_peer_ediv; 364 uint8_t sm_peer_rand[8]; 365 sm_key_t sm_peer_ltk; 366 sm_key_t sm_peer_irk; 367 sm_key_t sm_peer_csrk; 368 uint8_t sm_peer_addr_type; 369 bd_addr_t sm_peer_address; 370 #ifdef ENABLE_LE_SIGNED_WRITE 371 int sm_le_device_index; 372 #endif 373 374 } sm_setup_context_t; 375 376 // 377 static sm_setup_context_t the_setup; 378 static sm_setup_context_t * setup = &the_setup; 379 380 // active connection - the one for which the_setup is used for 381 static uint16_t sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 382 383 // @returns 1 if oob data is available 384 // stores oob data in provided 16 byte buffer if not null 385 static int (*sm_get_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_data) = NULL; 386 static int (*sm_get_sc_oob_data)(uint8_t addres_type, bd_addr_t addr, uint8_t * oob_sc_peer_confirm, uint8_t * oob_sc_peer_random); 387 388 static void sm_run(void); 389 static void sm_done_for_handle(hci_con_handle_t con_handle); 390 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle); 391 static inline int sm_calc_actual_encryption_key_size(int other); 392 static int sm_validate_stk_generation_method(void); 393 static void sm_handle_encryption_result_address_resolution(void *arg); 394 static void sm_handle_encryption_result_dkg_dhk(void *arg); 395 static void sm_handle_encryption_result_dkg_irk(void *arg); 396 static void sm_handle_encryption_result_enc_a(void *arg); 397 static void sm_handle_encryption_result_enc_b(void *arg); 398 static void sm_handle_encryption_result_enc_c(void *arg); 399 static void sm_handle_encryption_result_enc_csrk(void *arg); 400 static void sm_handle_encryption_result_enc_d(void * arg); 401 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg); 402 static void sm_handle_encryption_result_enc_ph3_y(void *arg); 403 #ifdef ENABLE_LE_PERIPHERAL 404 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg); 405 static void sm_handle_encryption_result_enc_ph4_y(void *arg); 406 #endif 407 static void sm_handle_encryption_result_enc_stk(void *arg); 408 static void sm_handle_encryption_result_rau(void *arg); 409 static void sm_handle_random_result_ph2_tk(void * arg); 410 static void sm_handle_random_result_rau(void * arg); 411 #ifdef ENABLE_LE_SECURE_CONNECTIONS 412 static void sm_cmac_message_start(const sm_key_t key, uint16_t message_len, const uint8_t * message, void (*done_callback)(uint8_t * hash)); 413 static void sm_ec_generate_new_key(void); 414 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg); 415 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg); 416 static int sm_passkey_entry(stk_generation_method_t method); 417 #endif 418 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason); 419 420 static void log_info_hex16(const char * name, uint16_t value){ 421 log_info("%-6s 0x%04x", name, value); 422 } 423 424 // static inline uint8_t sm_pairing_packet_get_code(sm_pairing_packet_t packet){ 425 // return packet[0]; 426 // } 427 static inline uint8_t sm_pairing_packet_get_io_capability(sm_pairing_packet_t packet){ 428 return packet[1]; 429 } 430 static inline uint8_t sm_pairing_packet_get_oob_data_flag(sm_pairing_packet_t packet){ 431 return packet[2]; 432 } 433 static inline uint8_t sm_pairing_packet_get_auth_req(sm_pairing_packet_t packet){ 434 return packet[3]; 435 } 436 static inline uint8_t sm_pairing_packet_get_max_encryption_key_size(sm_pairing_packet_t packet){ 437 return packet[4]; 438 } 439 static inline uint8_t sm_pairing_packet_get_initiator_key_distribution(sm_pairing_packet_t packet){ 440 return packet[5]; 441 } 442 static inline uint8_t sm_pairing_packet_get_responder_key_distribution(sm_pairing_packet_t packet){ 443 return packet[6]; 444 } 445 446 static inline void sm_pairing_packet_set_code(sm_pairing_packet_t packet, uint8_t code){ 447 packet[0] = code; 448 } 449 static inline void sm_pairing_packet_set_io_capability(sm_pairing_packet_t packet, uint8_t io_capability){ 450 packet[1] = io_capability; 451 } 452 static inline void sm_pairing_packet_set_oob_data_flag(sm_pairing_packet_t packet, uint8_t oob_data_flag){ 453 packet[2] = oob_data_flag; 454 } 455 static inline void sm_pairing_packet_set_auth_req(sm_pairing_packet_t packet, uint8_t auth_req){ 456 packet[3] = auth_req; 457 } 458 static inline void sm_pairing_packet_set_max_encryption_key_size(sm_pairing_packet_t packet, uint8_t max_encryption_key_size){ 459 packet[4] = max_encryption_key_size; 460 } 461 static inline void sm_pairing_packet_set_initiator_key_distribution(sm_pairing_packet_t packet, uint8_t initiator_key_distribution){ 462 packet[5] = initiator_key_distribution; 463 } 464 static inline void sm_pairing_packet_set_responder_key_distribution(sm_pairing_packet_t packet, uint8_t responder_key_distribution){ 465 packet[6] = responder_key_distribution; 466 } 467 468 // @returns 1 if all bytes are 0 469 static int sm_is_null(uint8_t * data, int size){ 470 int i; 471 for (i=0; i < size ; i++){ 472 if (data[i] != 0) { 473 return 0; 474 } 475 } 476 return 1; 477 } 478 479 static int sm_is_null_random(uint8_t random[8]){ 480 return sm_is_null(random, 8); 481 } 482 483 static int sm_is_null_key(uint8_t * key){ 484 return sm_is_null(key, 16); 485 } 486 487 // sm_trigger_run allows to schedule callback from main run loop // reduces stack depth 488 static void sm_run_timer_handler(btstack_timer_source_t * ts){ 489 UNUSED(ts); 490 sm_run(); 491 } 492 static void sm_trigger_run(void){ 493 (void)btstack_run_loop_remove_timer(&sm_run_timer); 494 btstack_run_loop_set_timer(&sm_run_timer, 0); 495 btstack_run_loop_add_timer(&sm_run_timer); 496 } 497 498 // Key utils 499 static void sm_reset_tk(void){ 500 int i; 501 for (i=0;i<16;i++){ 502 setup->sm_tk[i] = 0; 503 } 504 } 505 506 // "For example, if a 128-bit encryption key is 0x123456789ABCDEF0123456789ABCDEF0 507 // and it is reduced to 7 octets (56 bits), then the resulting key is 0x0000000000000000003456789ABCDEF0."" 508 static void sm_truncate_key(sm_key_t key, int max_encryption_size){ 509 int i; 510 for (i = max_encryption_size ; i < 16 ; i++){ 511 key[15-i] = 0; 512 } 513 } 514 515 // ER / IR checks 516 static void sm_er_ir_set_default(void){ 517 int i; 518 for (i=0;i<16;i++){ 519 sm_persistent_er[i] = 0x30 + i; 520 sm_persistent_ir[i] = 0x90 + i; 521 } 522 } 523 524 static int sm_er_is_default(void){ 525 int i; 526 for (i=0;i<16;i++){ 527 if (sm_persistent_er[i] != (0x30+i)) return 0; 528 } 529 return 1; 530 } 531 532 static int sm_ir_is_default(void){ 533 int i; 534 for (i=0;i<16;i++){ 535 if (sm_persistent_ir[i] != (0x90+i)) return 0; 536 } 537 return 1; 538 } 539 540 // SMP Timeout implementation 541 542 // Upon transmission of the Pairing Request command or reception of the Pairing Request command, 543 // the Security Manager Timer shall be reset and started. 544 // 545 // The Security Manager Timer shall be reset when an L2CAP SMP command is queued for transmission. 546 // 547 // If the Security Manager Timer reaches 30 seconds, the procedure shall be considered to have failed, 548 // and the local higher layer shall be notified. No further SMP commands shall be sent over the L2CAP 549 // Security Manager Channel. A new SM procedure shall only be performed when a new physical link has been 550 // established. 551 552 static void sm_timeout_handler(btstack_timer_source_t * timer){ 553 log_info("SM timeout"); 554 sm_connection_t * sm_conn = (sm_connection_t*) btstack_run_loop_get_timer_context(timer); 555 sm_conn->sm_engine_state = SM_GENERAL_TIMEOUT; 556 sm_notify_client_status_reason(sm_conn, ERROR_CODE_CONNECTION_TIMEOUT, 0); 557 sm_done_for_handle(sm_conn->sm_handle); 558 559 // trigger handling of next ready connection 560 sm_run(); 561 } 562 static void sm_timeout_start(sm_connection_t * sm_conn){ 563 btstack_run_loop_remove_timer(&setup->sm_timeout); 564 btstack_run_loop_set_timer_context(&setup->sm_timeout, sm_conn); 565 btstack_run_loop_set_timer_handler(&setup->sm_timeout, sm_timeout_handler); 566 btstack_run_loop_set_timer(&setup->sm_timeout, 30000); // 30 seconds sm timeout 567 btstack_run_loop_add_timer(&setup->sm_timeout); 568 } 569 static void sm_timeout_stop(void){ 570 btstack_run_loop_remove_timer(&setup->sm_timeout); 571 } 572 static void sm_timeout_reset(sm_connection_t * sm_conn){ 573 sm_timeout_stop(); 574 sm_timeout_start(sm_conn); 575 } 576 577 // end of sm timeout 578 579 // GAP Random Address updates 580 static gap_random_address_type_t gap_random_adress_type; 581 static btstack_timer_source_t gap_random_address_update_timer; 582 static uint32_t gap_random_adress_update_period; 583 584 static void gap_random_address_trigger(void){ 585 log_info("gap_random_address_trigger, state %u", rau_state); 586 if (rau_state != RAU_IDLE) return; 587 rau_state = RAU_GET_RANDOM; 588 sm_trigger_run(); 589 } 590 591 static void gap_random_address_update_handler(btstack_timer_source_t * timer){ 592 UNUSED(timer); 593 594 log_info("GAP Random Address Update due"); 595 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 596 btstack_run_loop_add_timer(&gap_random_address_update_timer); 597 gap_random_address_trigger(); 598 } 599 600 static void gap_random_address_update_start(void){ 601 btstack_run_loop_set_timer_handler(&gap_random_address_update_timer, gap_random_address_update_handler); 602 btstack_run_loop_set_timer(&gap_random_address_update_timer, gap_random_adress_update_period); 603 btstack_run_loop_add_timer(&gap_random_address_update_timer); 604 } 605 606 static void gap_random_address_update_stop(void){ 607 btstack_run_loop_remove_timer(&gap_random_address_update_timer); 608 } 609 610 // ah(k,r) helper 611 // r = padding || r 612 // r - 24 bit value 613 static void sm_ah_r_prime(uint8_t r[3], uint8_t * r_prime){ 614 // r'= padding || r 615 memset(r_prime, 0, 16); 616 (void)memcpy(&r_prime[13], r, 3); 617 } 618 619 // d1 helper 620 // d' = padding || r || d 621 // d,r - 16 bit values 622 static void sm_d1_d_prime(uint16_t d, uint16_t r, uint8_t * d1_prime){ 623 // d'= padding || r || d 624 memset(d1_prime, 0, 16); 625 big_endian_store_16(d1_prime, 12, r); 626 big_endian_store_16(d1_prime, 14, d); 627 } 628 629 // calculate arguments for first AES128 operation in C1 function 630 static void sm_c1_t1(sm_key_t r, uint8_t preq[7], uint8_t pres[7], uint8_t iat, uint8_t rat, uint8_t * t1){ 631 632 // p1 = pres || preq || rat’ || iat’ 633 // "The octet of iat’ becomes the least significant octet of p1 and the most signifi- 634 // cant octet of pres becomes the most significant octet of p1. 635 // For example, if the 8-bit iat’ is 0x01, the 8-bit rat’ is 0x00, the 56-bit preq 636 // is 0x07071000000101 and the 56 bit pres is 0x05000800000302 then 637 // p1 is 0x05000800000302070710000001010001." 638 639 sm_key_t p1; 640 reverse_56(pres, &p1[0]); 641 reverse_56(preq, &p1[7]); 642 p1[14] = rat; 643 p1[15] = iat; 644 log_info_key("p1", p1); 645 log_info_key("r", r); 646 647 // t1 = r xor p1 648 int i; 649 for (i=0;i<16;i++){ 650 t1[i] = r[i] ^ p1[i]; 651 } 652 log_info_key("t1", t1); 653 } 654 655 // calculate arguments for second AES128 operation in C1 function 656 static void sm_c1_t3(sm_key_t t2, bd_addr_t ia, bd_addr_t ra, uint8_t * t3){ 657 // p2 = padding || ia || ra 658 // "The least significant octet of ra becomes the least significant octet of p2 and 659 // the most significant octet of padding becomes the most significant octet of p2. 660 // For example, if 48-bit ia is 0xA1A2A3A4A5A6 and the 48-bit ra is 661 // 0xB1B2B3B4B5B6 then p2 is 0x00000000A1A2A3A4A5A6B1B2B3B4B5B6. 662 663 sm_key_t p2; 664 memset(p2, 0, 16); 665 (void)memcpy(&p2[4], ia, 6); 666 (void)memcpy(&p2[10], ra, 6); 667 log_info_key("p2", p2); 668 669 // c1 = e(k, t2_xor_p2) 670 int i; 671 for (i=0;i<16;i++){ 672 t3[i] = t2[i] ^ p2[i]; 673 } 674 log_info_key("t3", t3); 675 } 676 677 static void sm_s1_r_prime(sm_key_t r1, sm_key_t r2, uint8_t * r_prime){ 678 log_info_key("r1", r1); 679 log_info_key("r2", r2); 680 (void)memcpy(&r_prime[8], &r2[8], 8); 681 (void)memcpy(&r_prime[0], &r1[8], 8); 682 } 683 684 static void sm_dispatch_event(uint8_t packet_type, uint16_t channel, uint8_t * packet, uint16_t size){ 685 UNUSED(channel); 686 687 // log event 688 hci_dump_packet(packet_type, 1, packet, size); 689 // dispatch to all event handlers 690 btstack_linked_list_iterator_t it; 691 btstack_linked_list_iterator_init(&it, &sm_event_handlers); 692 while (btstack_linked_list_iterator_has_next(&it)){ 693 btstack_packet_callback_registration_t * entry = (btstack_packet_callback_registration_t*) btstack_linked_list_iterator_next(&it); 694 entry->callback(packet_type, 0, packet, size); 695 } 696 } 697 698 static void sm_setup_event_base(uint8_t * event, int event_size, uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 699 event[0] = type; 700 event[1] = event_size - 2; 701 little_endian_store_16(event, 2, con_handle); 702 event[4] = addr_type; 703 reverse_bd_addr(address, &event[5]); 704 } 705 706 static void sm_notify_client_base(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address){ 707 uint8_t event[11]; 708 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 709 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 710 } 711 712 static void sm_notify_client_passkey(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint32_t passkey){ 713 uint8_t event[15]; 714 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 715 little_endian_store_32(event, 11, passkey); 716 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 717 } 718 719 static void sm_notify_client_index(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint16_t index){ 720 // fetch addr and addr type from db, only called for valid entries 721 bd_addr_t identity_address; 722 int identity_address_type; 723 le_device_db_info(index, &identity_address_type, identity_address, NULL); 724 725 uint8_t event[20]; 726 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 727 event[11] = identity_address_type; 728 reverse_bd_addr(identity_address, &event[12]); 729 little_endian_store_16(event, 18, index); 730 sm_dispatch_event(HCI_EVENT_PACKET, 0, event, sizeof(event)); 731 } 732 733 static void sm_notify_client_status(uint8_t type, hci_con_handle_t con_handle, uint8_t addr_type, bd_addr_t address, uint8_t status){ 734 uint8_t event[12]; 735 sm_setup_event_base(event, sizeof(event), type, con_handle, addr_type, address); 736 event[11] = status; 737 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 738 } 739 740 static void sm_notify_client_status_reason(sm_connection_t * sm_conn, uint8_t status, uint8_t reason){ 741 uint8_t event[13]; 742 sm_setup_event_base(event, sizeof(event), SM_EVENT_PAIRING_COMPLETE, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address); 743 event[11] = status; 744 event[12] = reason; 745 sm_dispatch_event(HCI_EVENT_PACKET, 0, (uint8_t*) &event, sizeof(event)); 746 } 747 748 // decide on stk generation based on 749 // - pairing request 750 // - io capabilities 751 // - OOB data availability 752 static void sm_setup_tk(void){ 753 754 // horizontal: initiator capabilities 755 // vertial: responder capabilities 756 static const stk_generation_method_t stk_generation_method [5] [5] = { 757 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 758 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 759 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 760 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 761 { PK_RESP_INPUT, PK_RESP_INPUT, PK_INIT_INPUT, JUST_WORKS, PK_RESP_INPUT }, 762 }; 763 764 // uses numeric comparison if one side has DisplayYesNo and KeyboardDisplay combinations 765 #ifdef ENABLE_LE_SECURE_CONNECTIONS 766 static const stk_generation_method_t stk_generation_method_with_secure_connection[5][5] = { 767 { JUST_WORKS, JUST_WORKS, PK_INIT_INPUT, JUST_WORKS, PK_INIT_INPUT }, 768 { JUST_WORKS, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 769 { PK_RESP_INPUT, PK_RESP_INPUT, PK_BOTH_INPUT, JUST_WORKS, PK_RESP_INPUT }, 770 { JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS, JUST_WORKS }, 771 { PK_RESP_INPUT, NUMERIC_COMPARISON, PK_INIT_INPUT, JUST_WORKS, NUMERIC_COMPARISON }, 772 }; 773 #endif 774 775 // default: just works 776 setup->sm_stk_generation_method = JUST_WORKS; 777 778 #ifdef ENABLE_LE_SECURE_CONNECTIONS 779 setup->sm_use_secure_connections = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 780 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 781 & SM_AUTHREQ_SECURE_CONNECTION ) != 0u; 782 #else 783 setup->sm_use_secure_connections = 0; 784 #endif 785 log_info("Secure pairing: %u", setup->sm_use_secure_connections); 786 787 788 // decide if OOB will be used based on SC vs. Legacy and oob flags 789 int use_oob = 0; 790 if (setup->sm_use_secure_connections){ 791 // In LE Secure Connections pairing, the out of band method is used if at least 792 // one device has the peer device's out of band authentication data available. 793 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) | sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 794 } else { 795 // In LE legacy pairing, the out of band method is used if both the devices have 796 // the other device's out of band authentication data available. 797 use_oob = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) & sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 798 } 799 if (use_oob){ 800 log_info("SM: have OOB data"); 801 log_info_key("OOB", setup->sm_tk); 802 setup->sm_stk_generation_method = OOB; 803 return; 804 } 805 806 // If both devices have not set the MITM option in the Authentication Requirements 807 // Flags, then the IO capabilities shall be ignored and the Just Works association 808 // model shall be used. 809 if (((sm_pairing_packet_get_auth_req(setup->sm_m_preq) & SM_AUTHREQ_MITM_PROTECTION) == 0u) 810 && ((sm_pairing_packet_get_auth_req(setup->sm_s_pres) & SM_AUTHREQ_MITM_PROTECTION) == 0u)){ 811 log_info("SM: MITM not required by both -> JUST WORKS"); 812 return; 813 } 814 815 // Reset TK as it has been setup in sm_init_setup 816 sm_reset_tk(); 817 818 // Also use just works if unknown io capabilites 819 if ((sm_pairing_packet_get_io_capability(setup->sm_m_preq) > IO_CAPABILITY_KEYBOARD_DISPLAY) || (sm_pairing_packet_get_io_capability(setup->sm_s_pres) > IO_CAPABILITY_KEYBOARD_DISPLAY)){ 820 return; 821 } 822 823 // Otherwise the IO capabilities of the devices shall be used to determine the 824 // pairing method as defined in Table 2.4. 825 // see http://stackoverflow.com/a/1052837/393697 for how to specify pointer to 2-dimensional array 826 const stk_generation_method_t (*generation_method)[5] = stk_generation_method; 827 828 #ifdef ENABLE_LE_SECURE_CONNECTIONS 829 // table not define by default 830 if (setup->sm_use_secure_connections){ 831 generation_method = stk_generation_method_with_secure_connection; 832 } 833 #endif 834 setup->sm_stk_generation_method = generation_method[sm_pairing_packet_get_io_capability(setup->sm_s_pres)][sm_pairing_packet_get_io_capability(setup->sm_m_preq)]; 835 836 log_info("sm_setup_tk: master io cap: %u, slave io cap: %u -> method %u", 837 sm_pairing_packet_get_io_capability(setup->sm_m_preq), sm_pairing_packet_get_io_capability(setup->sm_s_pres), setup->sm_stk_generation_method); 838 } 839 840 static int sm_key_distribution_flags_for_set(uint8_t key_set){ 841 int flags = 0; 842 if (key_set & SM_KEYDIST_ENC_KEY){ 843 flags |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 844 flags |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 845 } 846 if (key_set & SM_KEYDIST_ID_KEY){ 847 flags |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 848 flags |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 849 } 850 if (key_set & SM_KEYDIST_SIGN){ 851 flags |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 852 } 853 return flags; 854 } 855 856 static void sm_setup_key_distribution(uint8_t key_set){ 857 setup->sm_key_distribution_received_set = 0; 858 setup->sm_key_distribution_send_set = sm_key_distribution_flags_for_set(key_set); 859 setup->sm_key_distribution_sent_set = 0; 860 #ifdef ENABLE_LE_SIGNED_WRITE 861 setup->sm_le_device_index = -1; 862 #endif 863 } 864 865 // CSRK Key Lookup 866 867 868 static int sm_address_resolution_idle(void){ 869 return sm_address_resolution_mode == ADDRESS_RESOLUTION_IDLE; 870 } 871 872 static void sm_address_resolution_start_lookup(uint8_t addr_type, hci_con_handle_t con_handle, bd_addr_t addr, address_resolution_mode_t mode, void * context){ 873 (void)memcpy(sm_address_resolution_address, addr, 6); 874 sm_address_resolution_addr_type = addr_type; 875 sm_address_resolution_test = 0; 876 sm_address_resolution_mode = mode; 877 sm_address_resolution_context = context; 878 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_STARTED, con_handle, addr_type, addr); 879 } 880 881 int sm_address_resolution_lookup(uint8_t address_type, bd_addr_t address){ 882 // check if already in list 883 btstack_linked_list_iterator_t it; 884 sm_lookup_entry_t * entry; 885 btstack_linked_list_iterator_init(&it, &sm_address_resolution_general_queue); 886 while(btstack_linked_list_iterator_has_next(&it)){ 887 entry = (sm_lookup_entry_t *) btstack_linked_list_iterator_next(&it); 888 if (entry->address_type != address_type) continue; 889 if (memcmp(entry->address, address, 6)) continue; 890 // already in list 891 return BTSTACK_BUSY; 892 } 893 entry = btstack_memory_sm_lookup_entry_get(); 894 if (!entry) return BTSTACK_MEMORY_ALLOC_FAILED; 895 entry->address_type = (bd_addr_type_t) address_type; 896 (void)memcpy(entry->address, address, 6); 897 btstack_linked_list_add(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 898 sm_trigger_run(); 899 return 0; 900 } 901 902 // CMAC calculation using AES Engineq 903 #ifdef USE_CMAC_ENGINE 904 905 static void sm_cmac_done_trampoline(void * arg){ 906 UNUSED(arg); 907 sm_cmac_active = 0; 908 (*sm_cmac_done_callback)(sm_cmac_hash); 909 sm_trigger_run(); 910 } 911 912 int sm_cmac_ready(void){ 913 return sm_cmac_active == 0u; 914 } 915 #endif 916 917 #ifdef ENABLE_LE_SECURE_CONNECTIONS 918 // generic cmac calculation 919 static void sm_cmac_message_start(const sm_key_t key, uint16_t message_len, const uint8_t * message, void (*done_callback)(uint8_t * hash)){ 920 sm_cmac_active = 1; 921 sm_cmac_done_callback = done_callback; 922 btstack_crypto_aes128_cmac_message(&sm_cmac_request, key, message_len, message, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 923 } 924 #endif 925 926 // cmac for ATT Message signing 927 #ifdef ENABLE_LE_SIGNED_WRITE 928 929 static void sm_cmac_generator_start(const sm_key_t key, uint16_t message_len, uint8_t (*get_byte_callback)(uint16_t offset), void (*done_callback)(uint8_t * hash)){ 930 sm_cmac_active = 1; 931 sm_cmac_done_callback = done_callback; 932 btstack_crypto_aes128_cmac_generator(&sm_cmac_request, key, message_len, get_byte_callback, sm_cmac_hash, sm_cmac_done_trampoline, NULL); 933 } 934 935 static uint8_t sm_cmac_signed_write_message_get_byte(uint16_t offset){ 936 if (offset >= sm_cmac_signed_write_message_len) { 937 log_error("sm_cmac_signed_write_message_get_byte. out of bounds, access %u, len %u", offset, sm_cmac_signed_write_message_len); 938 return 0; 939 } 940 941 offset = sm_cmac_signed_write_message_len - 1 - offset; 942 943 // sm_cmac_signed_write_header[3] | message[] | sm_cmac_signed_write_sign_counter[4] 944 if (offset < 3){ 945 return sm_cmac_signed_write_header[offset]; 946 } 947 int actual_message_len_incl_header = sm_cmac_signed_write_message_len - 4; 948 if (offset < actual_message_len_incl_header){ 949 return sm_cmac_signed_write_message[offset - 3]; 950 } 951 return sm_cmac_signed_write_sign_counter[offset - actual_message_len_incl_header]; 952 } 953 954 void sm_cmac_signed_write_start(const sm_key_t k, uint8_t opcode, hci_con_handle_t con_handle, uint16_t message_len, const uint8_t * message, uint32_t sign_counter, void (*done_handler)(uint8_t * hash)){ 955 // ATT Message Signing 956 sm_cmac_signed_write_header[0] = opcode; 957 little_endian_store_16(sm_cmac_signed_write_header, 1, con_handle); 958 little_endian_store_32(sm_cmac_signed_write_sign_counter, 0, sign_counter); 959 uint16_t total_message_len = 3 + message_len + 4; // incl. virtually prepended att opcode, handle and appended sign_counter in LE 960 sm_cmac_signed_write_message = message; 961 sm_cmac_signed_write_message_len = total_message_len; 962 sm_cmac_generator_start(k, total_message_len, &sm_cmac_signed_write_message_get_byte, done_handler); 963 } 964 #endif 965 966 static void sm_trigger_user_response(sm_connection_t * sm_conn){ 967 // notify client for: JUST WORKS confirm, Numeric comparison confirm, PASSKEY display or input 968 setup->sm_user_response = SM_USER_RESPONSE_IDLE; 969 switch (setup->sm_stk_generation_method){ 970 case PK_RESP_INPUT: 971 if (IS_RESPONDER(sm_conn->sm_role)){ 972 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 973 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 974 } else { 975 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 976 } 977 break; 978 case PK_INIT_INPUT: 979 if (IS_RESPONDER(sm_conn->sm_role)){ 980 sm_notify_client_passkey(SM_EVENT_PASSKEY_DISPLAY_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 981 } else { 982 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 983 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 984 } 985 break; 986 case PK_BOTH_INPUT: 987 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 988 sm_notify_client_base(SM_EVENT_PASSKEY_INPUT_NUMBER, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 989 break; 990 case NUMERIC_COMPARISON: 991 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 992 sm_notify_client_passkey(SM_EVENT_NUMERIC_COMPARISON_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, big_endian_read_32(setup->sm_tk, 12)); 993 break; 994 case JUST_WORKS: 995 setup->sm_user_response = SM_USER_RESPONSE_PENDING; 996 sm_notify_client_base(SM_EVENT_JUST_WORKS_REQUEST, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 997 break; 998 case OOB: 999 // client already provided OOB data, let's skip notification. 1000 break; 1001 } 1002 } 1003 1004 static int sm_key_distribution_all_received(sm_connection_t * sm_conn){ 1005 int recv_flags; 1006 if (IS_RESPONDER(sm_conn->sm_role)){ 1007 // slave / responder 1008 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres)); 1009 } else { 1010 // master / initiator 1011 recv_flags = sm_key_distribution_flags_for_set(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 1012 } 1013 1014 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1015 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1016 if (setup->sm_use_secure_connections){ 1017 recv_flags &= ~(SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION | SM_KEYDIST_FLAG_MASTER_IDENTIFICATION); 1018 } 1019 #endif 1020 1021 log_debug("sm_key_distribution_all_received: received 0x%02x, expecting 0x%02x", setup->sm_key_distribution_received_set, recv_flags); 1022 return (setup->sm_key_distribution_received_set & recv_flags) == recv_flags; 1023 } 1024 1025 static void sm_done_for_handle(hci_con_handle_t con_handle){ 1026 if (sm_active_connection_handle == con_handle){ 1027 sm_timeout_stop(); 1028 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 1029 log_info("sm: connection 0x%x released setup context", con_handle); 1030 1031 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1032 // generate new ec key after each pairing (that used it) 1033 if (setup->sm_use_secure_connections){ 1034 sm_ec_generate_new_key(); 1035 } 1036 #endif 1037 } 1038 } 1039 1040 static void sm_master_pairing_success(sm_connection_t *connection) {// master -> all done 1041 connection->sm_engine_state = SM_INITIATOR_CONNECTED; 1042 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 1043 sm_done_for_handle(connection->sm_handle); 1044 } 1045 1046 static int sm_key_distribution_flags_for_auth_req(void){ 1047 1048 int flags = SM_KEYDIST_ID_KEY; 1049 if (sm_auth_req & SM_AUTHREQ_BONDING){ 1050 // encryption and signing information only if bonding requested 1051 flags |= SM_KEYDIST_ENC_KEY; 1052 #ifdef ENABLE_LE_SIGNED_WRITE 1053 flags |= SM_KEYDIST_SIGN; 1054 #endif 1055 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1056 // LinkKey for CTKD requires SC 1057 if (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 1058 flags |= SM_KEYDIST_LINK_KEY; 1059 } 1060 #endif 1061 } 1062 return flags; 1063 } 1064 1065 static void sm_reset_setup(void){ 1066 // fill in sm setup 1067 setup->sm_state_vars = 0; 1068 setup->sm_keypress_notification = 0; 1069 sm_reset_tk(); 1070 } 1071 1072 static void sm_init_setup(sm_connection_t * sm_conn){ 1073 1074 // fill in sm setup 1075 setup->sm_peer_addr_type = sm_conn->sm_peer_addr_type; 1076 (void)memcpy(setup->sm_peer_address, sm_conn->sm_peer_address, 6); 1077 1078 // query client for Legacy Pairing OOB data 1079 setup->sm_have_oob_data = 0; 1080 if (sm_get_oob_data) { 1081 setup->sm_have_oob_data = (*sm_get_oob_data)(sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, setup->sm_tk); 1082 } 1083 1084 // if available and SC supported, also ask for SC OOB Data 1085 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1086 memset(setup->sm_ra, 0, 16); 1087 memset(setup->sm_rb, 0, 16); 1088 if (setup->sm_have_oob_data && (sm_auth_req & SM_AUTHREQ_SECURE_CONNECTION)){ 1089 if (sm_get_sc_oob_data){ 1090 if (IS_RESPONDER(sm_conn->sm_role)){ 1091 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1092 sm_conn->sm_peer_addr_type, 1093 sm_conn->sm_peer_address, 1094 setup->sm_peer_confirm, 1095 setup->sm_ra); 1096 } else { 1097 setup->sm_have_oob_data = (*sm_get_sc_oob_data)( 1098 sm_conn->sm_peer_addr_type, 1099 sm_conn->sm_peer_address, 1100 setup->sm_peer_confirm, 1101 setup->sm_rb); 1102 } 1103 } else { 1104 setup->sm_have_oob_data = 0; 1105 } 1106 } 1107 #endif 1108 1109 sm_pairing_packet_t * local_packet; 1110 if (IS_RESPONDER(sm_conn->sm_role)){ 1111 // slave 1112 local_packet = &setup->sm_s_pres; 1113 gap_le_get_own_address(&setup->sm_s_addr_type, setup->sm_s_address); 1114 setup->sm_m_addr_type = sm_conn->sm_peer_addr_type; 1115 (void)memcpy(setup->sm_m_address, sm_conn->sm_peer_address, 6); 1116 } else { 1117 // master 1118 local_packet = &setup->sm_m_preq; 1119 gap_le_get_own_address(&setup->sm_m_addr_type, setup->sm_m_address); 1120 setup->sm_s_addr_type = sm_conn->sm_peer_addr_type; 1121 (void)memcpy(setup->sm_s_address, sm_conn->sm_peer_address, 6); 1122 1123 int key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 1124 sm_pairing_packet_set_initiator_key_distribution(setup->sm_m_preq, key_distribution_flags); 1125 sm_pairing_packet_set_responder_key_distribution(setup->sm_m_preq, key_distribution_flags); 1126 } 1127 1128 uint8_t auth_req = sm_auth_req & ~SM_AUTHREQ_CT2; 1129 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1130 // set CT2 if SC + Bonding + CTKD 1131 const uint8_t auth_req_for_ct2 = SM_AUTHREQ_SECURE_CONNECTION | SM_AUTHREQ_BONDING; 1132 if ((auth_req & auth_req_for_ct2) == auth_req_for_ct2){ 1133 auth_req |= SM_AUTHREQ_CT2; 1134 } 1135 #endif 1136 sm_pairing_packet_set_io_capability(*local_packet, sm_io_capabilities); 1137 sm_pairing_packet_set_oob_data_flag(*local_packet, setup->sm_have_oob_data); 1138 sm_pairing_packet_set_auth_req(*local_packet, auth_req); 1139 sm_pairing_packet_set_max_encryption_key_size(*local_packet, sm_max_encryption_key_size); 1140 } 1141 1142 static int sm_stk_generation_init(sm_connection_t * sm_conn){ 1143 1144 sm_pairing_packet_t * remote_packet; 1145 int remote_key_request; 1146 if (IS_RESPONDER(sm_conn->sm_role)){ 1147 // slave / responder 1148 remote_packet = &setup->sm_m_preq; 1149 remote_key_request = sm_pairing_packet_get_responder_key_distribution(setup->sm_m_preq); 1150 } else { 1151 // master / initiator 1152 remote_packet = &setup->sm_s_pres; 1153 remote_key_request = sm_pairing_packet_get_initiator_key_distribution(setup->sm_s_pres); 1154 } 1155 1156 // check key size 1157 sm_conn->sm_actual_encryption_key_size = sm_calc_actual_encryption_key_size(sm_pairing_packet_get_max_encryption_key_size(*remote_packet)); 1158 if (sm_conn->sm_actual_encryption_key_size == 0u) return SM_REASON_ENCRYPTION_KEY_SIZE; 1159 1160 // decide on STK generation method / SC 1161 sm_setup_tk(); 1162 log_info("SMP: generation method %u", setup->sm_stk_generation_method); 1163 1164 // check if STK generation method is acceptable by client 1165 if (!sm_validate_stk_generation_method()) return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1166 1167 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1168 // check LE SC Only mode 1169 if (sm_sc_only_mode && (setup->sm_use_secure_connections == false)){ 1170 log_info("SC Only mode active but SC not possible"); 1171 return SM_REASON_AUTHENTHICATION_REQUIREMENTS; 1172 } 1173 1174 // LTK (= encyrption information & master identification) only used exchanged for LE Legacy Connection 1175 if (setup->sm_use_secure_connections){ 1176 remote_key_request &= ~SM_KEYDIST_ENC_KEY; 1177 } 1178 #endif 1179 1180 // identical to responder 1181 sm_setup_key_distribution(remote_key_request); 1182 1183 // JUST WORKS doens't provide authentication 1184 sm_conn->sm_connection_authenticated = (setup->sm_stk_generation_method == JUST_WORKS) ? 0 : 1; 1185 1186 return 0; 1187 } 1188 1189 static void sm_address_resolution_handle_event(address_resolution_event_t event){ 1190 1191 // cache and reset context 1192 int matched_device_id = sm_address_resolution_test; 1193 address_resolution_mode_t mode = sm_address_resolution_mode; 1194 void * context = sm_address_resolution_context; 1195 1196 // reset context 1197 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 1198 sm_address_resolution_context = NULL; 1199 sm_address_resolution_test = -1; 1200 hci_con_handle_t con_handle = 0; 1201 1202 sm_connection_t * sm_connection; 1203 #ifdef ENABLE_LE_CENTRAL 1204 sm_key_t ltk; 1205 int have_ltk; 1206 int pairing_need; 1207 #endif 1208 switch (mode){ 1209 case ADDRESS_RESOLUTION_GENERAL: 1210 break; 1211 case ADDRESS_RESOLUTION_FOR_CONNECTION: 1212 sm_connection = (sm_connection_t *) context; 1213 con_handle = sm_connection->sm_handle; 1214 switch (event){ 1215 case ADDRESS_RESOLUTION_SUCEEDED: 1216 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1217 sm_connection->sm_le_db_index = matched_device_id; 1218 log_info("ADDRESS_RESOLUTION_SUCEEDED, index %d", sm_connection->sm_le_db_index); 1219 if (sm_connection->sm_role) { 1220 // LTK request received before, IRK required -> start LTK calculation 1221 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1222 sm_connection->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 1223 } 1224 break; 1225 } 1226 #ifdef ENABLE_LE_CENTRAL 1227 le_device_db_encryption_get(sm_connection->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 1228 have_ltk = !sm_is_null_key(ltk); 1229 pairing_need = sm_connection->sm_pairing_requested || sm_connection->sm_security_request_received; 1230 log_info("central: pairing request local %u, remote %u => action %u. have_ltk %u", 1231 sm_connection->sm_pairing_requested, sm_connection->sm_security_request_received, pairing_need, have_ltk); 1232 // reset requests 1233 sm_connection->sm_security_request_received = 0; 1234 sm_connection->sm_pairing_requested = 0; 1235 1236 // have ltk -> start encryption 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 if (have_ltk){ 1241 #ifdef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 1242 sm_connection->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 1243 break; 1244 #else 1245 log_info("central: defer enabling encryption for bonded device"); 1246 #endif 1247 } 1248 // pairint_request -> send pairing request 1249 if (pairing_need){ 1250 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1251 break; 1252 } 1253 #endif 1254 break; 1255 case ADDRESS_RESOLUTION_FAILED: 1256 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_FAILED; 1257 if (sm_connection->sm_role) { 1258 // LTK request received before, IRK required -> negative LTK reply 1259 if (sm_connection->sm_engine_state == SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK){ 1260 sm_connection->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 1261 } 1262 break; 1263 } 1264 #ifdef ENABLE_LE_CENTRAL 1265 if (!sm_connection->sm_pairing_requested && !sm_connection->sm_security_request_received) break; 1266 sm_connection->sm_security_request_received = 0; 1267 sm_connection->sm_pairing_requested = 0; 1268 sm_connection->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 1269 #endif 1270 break; 1271 } 1272 break; 1273 default: 1274 break; 1275 } 1276 1277 switch (event){ 1278 case ADDRESS_RESOLUTION_SUCEEDED: 1279 sm_notify_client_index(SM_EVENT_IDENTITY_RESOLVING_SUCCEEDED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address, matched_device_id); 1280 break; 1281 case ADDRESS_RESOLUTION_FAILED: 1282 sm_notify_client_base(SM_EVENT_IDENTITY_RESOLVING_FAILED, con_handle, sm_address_resolution_addr_type, sm_address_resolution_address); 1283 break; 1284 } 1285 } 1286 1287 static void sm_key_distribution_handle_all_received(sm_connection_t * sm_conn){ 1288 1289 int le_db_index = -1; 1290 1291 // only store pairing information if both sides are bondable, i.e., the bonadble flag is set 1292 int bonding_enabed = ( sm_pairing_packet_get_auth_req(setup->sm_m_preq) 1293 & sm_pairing_packet_get_auth_req(setup->sm_s_pres) 1294 & SM_AUTHREQ_BONDING ) != 0u; 1295 1296 if (bonding_enabed){ 1297 1298 // lookup device based on IRK 1299 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 1300 int i; 1301 for (i=0; i < le_device_db_max_count(); i++){ 1302 sm_key_t irk; 1303 bd_addr_t address; 1304 int address_type = BD_ADDR_TYPE_UNKNOWN; 1305 le_device_db_info(i, &address_type, address, irk); 1306 // skip unused entries 1307 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1308 // compare IRK 1309 if (memcmp(irk, setup->sm_peer_irk, 16) != 0) continue; 1310 1311 log_info("sm: device found for IRK, updating"); 1312 le_db_index = i; 1313 break; 1314 } 1315 } else { 1316 // assert IRK is set to zero 1317 memset(setup->sm_peer_irk, 0, 16); 1318 } 1319 1320 // if not found, lookup via public address if possible 1321 log_info("sm peer addr type %u, peer addres %s", setup->sm_peer_addr_type, bd_addr_to_str(setup->sm_peer_address)); 1322 if ((le_db_index < 0) && (setup->sm_peer_addr_type == BD_ADDR_TYPE_LE_PUBLIC)){ 1323 int i; 1324 for (i=0; i < le_device_db_max_count(); i++){ 1325 bd_addr_t address; 1326 int address_type = BD_ADDR_TYPE_UNKNOWN; 1327 le_device_db_info(i, &address_type, address, NULL); 1328 // skip unused entries 1329 if (address_type == BD_ADDR_TYPE_UNKNOWN) continue; 1330 log_info("device %u, sm peer addr type %u, peer addres %s", i, address_type, bd_addr_to_str(address)); 1331 if ((address_type == BD_ADDR_TYPE_LE_PUBLIC) && (memcmp(address, setup->sm_peer_address, 6) == 0)){ 1332 log_info("sm: device found for public address, updating"); 1333 le_db_index = i; 1334 break; 1335 } 1336 } 1337 } 1338 1339 // if not found, add to db 1340 bool new_to_le_device_db = false; 1341 if (le_db_index < 0) { 1342 le_db_index = le_device_db_add(setup->sm_peer_addr_type, setup->sm_peer_address, setup->sm_peer_irk); 1343 new_to_le_device_db = true; 1344 } 1345 1346 if (le_db_index >= 0){ 1347 1348 #ifdef ENABLE_LE_PRIVACY_ADDRESS_RESOLUTION 1349 if (!new_to_le_device_db){ 1350 hci_remove_le_device_db_entry_from_resolving_list(le_db_index); 1351 } 1352 hci_load_le_device_db_entry_into_resolving_list(le_db_index); 1353 #else 1354 UNUSED(new_to_le_device_db); 1355 #endif 1356 1357 sm_notify_client_index(SM_EVENT_IDENTITY_CREATED, sm_conn->sm_handle, setup->sm_peer_addr_type, setup->sm_peer_address, le_db_index); 1358 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_SUCCEEDED; 1359 1360 #ifdef ENABLE_LE_SIGNED_WRITE 1361 // store local CSRK 1362 setup->sm_le_device_index = le_db_index; 1363 if ((setup->sm_key_distribution_sent_set) & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1364 log_info("sm: store local CSRK"); 1365 le_device_db_local_csrk_set(le_db_index, setup->sm_local_csrk); 1366 le_device_db_local_counter_set(le_db_index, 0); 1367 } 1368 1369 // store remote CSRK 1370 if (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 1371 log_info("sm: store remote CSRK"); 1372 le_device_db_remote_csrk_set(le_db_index, setup->sm_peer_csrk); 1373 le_device_db_remote_counter_set(le_db_index, 0); 1374 } 1375 #endif 1376 // store encryption information for secure connections: LTK generated by ECDH 1377 if (setup->sm_use_secure_connections){ 1378 log_info("sm: store SC LTK (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1379 uint8_t zero_rand[8]; 1380 memset(zero_rand, 0, 8); 1381 le_device_db_encryption_set(le_db_index, 0, zero_rand, setup->sm_ltk, sm_conn->sm_actual_encryption_key_size, 1382 sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 1); 1383 } 1384 1385 // store encryption information for legacy pairing: peer LTK, EDIV, RAND 1386 else if ( (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION) 1387 && (setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION )){ 1388 log_info("sm: set encryption information (key size %u, authenticated %u)", sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated); 1389 le_device_db_encryption_set(le_db_index, setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1390 sm_conn->sm_actual_encryption_key_size, sm_conn->sm_connection_authenticated, sm_conn->sm_connection_authorization_state == AUTHORIZATION_GRANTED, 0); 1391 1392 } 1393 } 1394 } else { 1395 log_info("Ignoring received keys, bonding not enabled"); 1396 } 1397 1398 // keep le_db_index 1399 sm_conn->sm_le_db_index = le_db_index; 1400 } 1401 1402 static void sm_pairing_error(sm_connection_t * sm_conn, uint8_t reason){ 1403 setup->sm_pairing_failed_reason = reason; 1404 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 1405 } 1406 1407 static inline void sm_pdu_received_in_wrong_state(sm_connection_t * sm_conn){ 1408 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 1409 } 1410 1411 #ifdef ENABLE_LE_SECURE_CONNECTIONS 1412 1413 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn); 1414 static int sm_passkey_used(stk_generation_method_t method); 1415 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method); 1416 1417 static void sm_sc_start_calculating_local_confirm(sm_connection_t * sm_conn){ 1418 if (setup->sm_stk_generation_method == OOB){ 1419 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 1420 } else { 1421 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); 1422 } 1423 } 1424 1425 static void sm_sc_state_after_receiving_random(sm_connection_t * sm_conn){ 1426 if (IS_RESPONDER(sm_conn->sm_role)){ 1427 // Responder 1428 if (setup->sm_stk_generation_method == OOB){ 1429 // generate Nb 1430 log_info("Generate Nb"); 1431 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); 1432 } else { 1433 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 1434 } 1435 } else { 1436 // Initiator role 1437 switch (setup->sm_stk_generation_method){ 1438 case JUST_WORKS: 1439 sm_sc_prepare_dhkey_check(sm_conn); 1440 break; 1441 1442 case NUMERIC_COMPARISON: 1443 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_G2; 1444 break; 1445 case PK_INIT_INPUT: 1446 case PK_RESP_INPUT: 1447 case PK_BOTH_INPUT: 1448 if (setup->sm_passkey_bit < 20u) { 1449 sm_sc_start_calculating_local_confirm(sm_conn); 1450 } else { 1451 sm_sc_prepare_dhkey_check(sm_conn); 1452 } 1453 break; 1454 case OOB: 1455 sm_sc_prepare_dhkey_check(sm_conn); 1456 break; 1457 } 1458 } 1459 } 1460 1461 static void sm_sc_cmac_done(uint8_t * hash){ 1462 log_info("sm_sc_cmac_done: "); 1463 log_info_hexdump(hash, 16); 1464 1465 if (sm_sc_oob_state == SM_SC_OOB_W4_CONFIRM){ 1466 sm_sc_oob_state = SM_SC_OOB_IDLE; 1467 (*sm_sc_oob_callback)(hash, sm_sc_oob_random); 1468 return; 1469 } 1470 1471 sm_connection_t * sm_conn = sm_cmac_connection; 1472 sm_cmac_connection = NULL; 1473 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1474 link_key_type_t link_key_type; 1475 #endif 1476 1477 switch (sm_conn->sm_engine_state){ 1478 case SM_SC_W4_CMAC_FOR_CONFIRMATION: 1479 (void)memcpy(setup->sm_local_confirm, hash, 16); 1480 sm_conn->sm_engine_state = SM_SC_SEND_CONFIRMATION; 1481 break; 1482 case SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION: 1483 // check 1484 if (0 != memcmp(hash, setup->sm_peer_confirm, 16)){ 1485 sm_pairing_error(sm_conn, SM_REASON_CONFIRM_VALUE_FAILED); 1486 break; 1487 } 1488 sm_sc_state_after_receiving_random(sm_conn); 1489 break; 1490 case SM_SC_W4_CALCULATE_G2: { 1491 uint32_t vab = big_endian_read_32(hash, 12) % 1000000; 1492 big_endian_store_32(setup->sm_tk, 12, vab); 1493 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 1494 sm_trigger_user_response(sm_conn); 1495 break; 1496 } 1497 case SM_SC_W4_CALCULATE_F5_SALT: 1498 (void)memcpy(setup->sm_t, hash, 16); 1499 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_MACKEY; 1500 break; 1501 case SM_SC_W4_CALCULATE_F5_MACKEY: 1502 (void)memcpy(setup->sm_mackey, hash, 16); 1503 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_LTK; 1504 break; 1505 case SM_SC_W4_CALCULATE_F5_LTK: 1506 // truncate sm_ltk, but keep full LTK for cross-transport key derivation in sm_local_ltk 1507 // Errata Service Release to the Bluetooth Specification: ESR09 1508 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1509 // Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1510 (void)memcpy(setup->sm_ltk, hash, 16); 1511 (void)memcpy(setup->sm_local_ltk, hash, 16); 1512 sm_truncate_key(setup->sm_ltk, sm_conn->sm_actual_encryption_key_size); 1513 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK; 1514 break; 1515 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 1516 (void)memcpy(setup->sm_local_dhkey_check, hash, 16); 1517 if (IS_RESPONDER(sm_conn->sm_role)){ 1518 // responder 1519 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_COMMAND_RECEIVED){ 1520 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 1521 } else { 1522 sm_conn->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 1523 } 1524 } else { 1525 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1526 } 1527 break; 1528 case SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 1529 if (0 != memcmp(hash, setup->sm_peer_dhkey_check, 16) ){ 1530 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 1531 break; 1532 } 1533 if (IS_RESPONDER(sm_conn->sm_role)){ 1534 // responder 1535 sm_conn->sm_engine_state = SM_SC_SEND_DHKEY_CHECK_COMMAND; 1536 } else { 1537 // initiator 1538 sm_conn->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 1539 } 1540 break; 1541 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1542 case SM_SC_W4_CALCULATE_ILK: 1543 (void)memcpy(setup->sm_t, hash, 16); 1544 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY; 1545 break; 1546 case SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY: 1547 reverse_128(hash, setup->sm_t); 1548 link_key_type = sm_conn->sm_connection_authenticated ? 1549 AUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256 : UNAUTHENTICATED_COMBINATION_KEY_GENERATED_FROM_P256; 1550 log_info("Derived classic link key from LE using h6, type %u", (int) link_key_type); 1551 gap_store_link_key_for_bd_addr(setup->sm_peer_address, setup->sm_t, link_key_type); 1552 if (IS_RESPONDER(sm_conn->sm_role)){ 1553 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 1554 } else { 1555 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 1556 } 1557 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 1558 sm_done_for_handle(sm_conn->sm_handle); 1559 break; 1560 #endif 1561 default: 1562 log_error("sm_sc_cmac_done in state %u", sm_conn->sm_engine_state); 1563 break; 1564 } 1565 sm_trigger_run(); 1566 } 1567 1568 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){ 1569 const uint16_t message_len = 65; 1570 sm_cmac_connection = sm_conn; 1571 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1572 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1573 sm_cmac_sc_buffer[64] = z; 1574 log_info("f4 key"); 1575 log_info_hexdump(x, 16); 1576 log_info("f4 message"); 1577 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1578 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1579 } 1580 1581 static const uint8_t f5_key_id[] = { 0x62, 0x74, 0x6c, 0x65 }; 1582 static const uint8_t f5_length[] = { 0x01, 0x00}; 1583 1584 static void f5_calculate_salt(sm_connection_t * sm_conn){ 1585 1586 static const sm_key_t f5_salt = { 0x6C ,0x88, 0x83, 0x91, 0xAA, 0xF5, 0xA5, 0x38, 0x60, 0x37, 0x0B, 0xDB, 0x5A, 0x60, 0x83, 0xBE}; 1587 1588 log_info("f5_calculate_salt"); 1589 // calculate salt for f5 1590 const uint16_t message_len = 32; 1591 sm_cmac_connection = sm_conn; 1592 (void)memcpy(sm_cmac_sc_buffer, setup->sm_dhkey, message_len); 1593 sm_cmac_message_start(f5_salt, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1594 } 1595 1596 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){ 1597 const uint16_t message_len = 53; 1598 sm_cmac_connection = sm_conn; 1599 1600 // f5(W, N1, N2, A1, A2) = AES-CMACT (Counter = 0 || keyID || N1 || N2|| A1|| A2 || Length = 256) -- this is the MacKey 1601 sm_cmac_sc_buffer[0] = 0; 1602 (void)memcpy(sm_cmac_sc_buffer + 01, f5_key_id, 4); 1603 (void)memcpy(sm_cmac_sc_buffer + 05, n1, 16); 1604 (void)memcpy(sm_cmac_sc_buffer + 21, n2, 16); 1605 (void)memcpy(sm_cmac_sc_buffer + 37, a1, 7); 1606 (void)memcpy(sm_cmac_sc_buffer + 44, a2, 7); 1607 (void)memcpy(sm_cmac_sc_buffer + 51, f5_length, 2); 1608 log_info("f5 key"); 1609 log_info_hexdump(t, 16); 1610 log_info("f5 message for MacKey"); 1611 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1612 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1613 } 1614 1615 static void f5_calculate_mackey(sm_connection_t * sm_conn){ 1616 sm_key56_t bd_addr_master, bd_addr_slave; 1617 bd_addr_master[0] = setup->sm_m_addr_type; 1618 bd_addr_slave[0] = setup->sm_s_addr_type; 1619 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1620 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1621 if (IS_RESPONDER(sm_conn->sm_role)){ 1622 // responder 1623 f5_mackkey(sm_conn, setup->sm_t, setup->sm_peer_nonce, setup->sm_local_nonce, bd_addr_master, bd_addr_slave); 1624 } else { 1625 // initiator 1626 f5_mackkey(sm_conn, setup->sm_t, setup->sm_local_nonce, setup->sm_peer_nonce, bd_addr_master, bd_addr_slave); 1627 } 1628 } 1629 1630 // note: must be called right after f5_mackey, as sm_cmac_buffer[1..52] will be reused 1631 static inline void f5_ltk(sm_connection_t * sm_conn, sm_key_t t){ 1632 const uint16_t message_len = 53; 1633 sm_cmac_connection = sm_conn; 1634 sm_cmac_sc_buffer[0] = 1; 1635 // 1..52 setup before 1636 log_info("f5 key"); 1637 log_info_hexdump(t, 16); 1638 log_info("f5 message for LTK"); 1639 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1640 sm_cmac_message_start(t, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1641 } 1642 1643 static void f5_calculate_ltk(sm_connection_t * sm_conn){ 1644 f5_ltk(sm_conn, setup->sm_t); 1645 } 1646 1647 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){ 1648 (void)memcpy(sm_cmac_sc_buffer, n1, 16); 1649 (void)memcpy(sm_cmac_sc_buffer + 16, n2, 16); 1650 (void)memcpy(sm_cmac_sc_buffer + 32, r, 16); 1651 (void)memcpy(sm_cmac_sc_buffer + 48, io_cap, 3); 1652 (void)memcpy(sm_cmac_sc_buffer + 51, a1, 7); 1653 (void)memcpy(sm_cmac_sc_buffer + 58, a2, 7); 1654 } 1655 1656 static void f6_engine(sm_connection_t * sm_conn, const sm_key_t w){ 1657 const uint16_t message_len = 65; 1658 sm_cmac_connection = sm_conn; 1659 log_info("f6 key"); 1660 log_info_hexdump(w, 16); 1661 log_info("f6 message"); 1662 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1663 sm_cmac_message_start(w, 65, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1664 } 1665 1666 // g2(U, V, X, Y) = AES-CMACX(U || V || Y) mod 2^32 1667 // - U is 256 bits 1668 // - V is 256 bits 1669 // - X is 128 bits 1670 // - Y is 128 bits 1671 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){ 1672 const uint16_t message_len = 80; 1673 sm_cmac_connection = sm_conn; 1674 (void)memcpy(sm_cmac_sc_buffer, u, 32); 1675 (void)memcpy(sm_cmac_sc_buffer + 32, v, 32); 1676 (void)memcpy(sm_cmac_sc_buffer + 64, y, 16); 1677 log_info("g2 key"); 1678 log_info_hexdump(x, 16); 1679 log_info("g2 message"); 1680 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1681 sm_cmac_message_start(x, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1682 } 1683 1684 static void g2_calculate(sm_connection_t * sm_conn) { 1685 // calc Va if numeric comparison 1686 if (IS_RESPONDER(sm_conn->sm_role)){ 1687 // responder 1688 g2_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, setup->sm_local_nonce);; 1689 } else { 1690 // initiator 1691 g2_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, setup->sm_peer_nonce); 1692 } 1693 } 1694 1695 static void sm_sc_calculate_local_confirm(sm_connection_t * sm_conn){ 1696 uint8_t z = 0; 1697 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1698 // some form of passkey 1699 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1700 z = 0x80u | ((pk >> setup->sm_passkey_bit) & 1u); 1701 setup->sm_passkey_bit++; 1702 } 1703 f4_engine(sm_conn, ec_q, setup->sm_peer_q, setup->sm_local_nonce, z); 1704 } 1705 1706 static void sm_sc_calculate_remote_confirm(sm_connection_t * sm_conn){ 1707 // OOB 1708 if (setup->sm_stk_generation_method == OOB){ 1709 if (IS_RESPONDER(sm_conn->sm_role)){ 1710 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_ra, 0); 1711 } else { 1712 f4_engine(sm_conn, setup->sm_peer_q, setup->sm_peer_q, setup->sm_rb, 0); 1713 } 1714 return; 1715 } 1716 1717 uint8_t z = 0; 1718 if (sm_passkey_entry(setup->sm_stk_generation_method)){ 1719 // some form of passkey 1720 uint32_t pk = big_endian_read_32(setup->sm_tk, 12); 1721 // sm_passkey_bit was increased before sending confirm value 1722 z = 0x80u | ((pk >> (setup->sm_passkey_bit-1u)) & 1u); 1723 } 1724 f4_engine(sm_conn, setup->sm_peer_q, ec_q, setup->sm_peer_nonce, z); 1725 } 1726 1727 static void sm_sc_prepare_dhkey_check(sm_connection_t * sm_conn){ 1728 log_info("sm_sc_prepare_dhkey_check, DHKEY calculated %u", (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED) ? 1 : 0); 1729 1730 if (setup->sm_state_vars & SM_STATE_VAR_DHKEY_CALCULATED){ 1731 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1732 return; 1733 } else { 1734 sm_conn->sm_engine_state = SM_SC_W4_CALCULATE_DHKEY; 1735 } 1736 } 1737 1738 static void sm_sc_dhkey_calculated(void * arg){ 1739 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 1740 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 1741 if (sm_conn == NULL) return; 1742 1743 log_info("dhkey"); 1744 log_info_hexdump(&setup->sm_dhkey[0], 32); 1745 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_CALCULATED; 1746 // trigger next step 1747 if (sm_conn->sm_engine_state == SM_SC_W4_CALCULATE_DHKEY){ 1748 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F5_SALT; 1749 } 1750 sm_trigger_run(); 1751 } 1752 1753 static void sm_sc_calculate_f6_for_dhkey_check(sm_connection_t * sm_conn){ 1754 // calculate DHKCheck 1755 sm_key56_t bd_addr_master, bd_addr_slave; 1756 bd_addr_master[0] = setup->sm_m_addr_type; 1757 bd_addr_slave[0] = setup->sm_s_addr_type; 1758 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1759 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1760 uint8_t iocap_a[3]; 1761 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1762 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1763 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1764 uint8_t iocap_b[3]; 1765 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1766 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1767 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1768 if (IS_RESPONDER(sm_conn->sm_role)){ 1769 // responder 1770 f6_setup(setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1771 f6_engine(sm_conn, setup->sm_mackey); 1772 } else { 1773 // initiator 1774 f6_setup( setup->sm_local_nonce, setup->sm_peer_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1775 f6_engine(sm_conn, setup->sm_mackey); 1776 } 1777 } 1778 1779 static void sm_sc_calculate_f6_to_verify_dhkey_check(sm_connection_t * sm_conn){ 1780 // validate E = f6() 1781 sm_key56_t bd_addr_master, bd_addr_slave; 1782 bd_addr_master[0] = setup->sm_m_addr_type; 1783 bd_addr_slave[0] = setup->sm_s_addr_type; 1784 (void)memcpy(&bd_addr_master[1], setup->sm_m_address, 6); 1785 (void)memcpy(&bd_addr_slave[1], setup->sm_s_address, 6); 1786 1787 uint8_t iocap_a[3]; 1788 iocap_a[0] = sm_pairing_packet_get_auth_req(setup->sm_m_preq); 1789 iocap_a[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq); 1790 iocap_a[2] = sm_pairing_packet_get_io_capability(setup->sm_m_preq); 1791 uint8_t iocap_b[3]; 1792 iocap_b[0] = sm_pairing_packet_get_auth_req(setup->sm_s_pres); 1793 iocap_b[1] = sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres); 1794 iocap_b[2] = sm_pairing_packet_get_io_capability(setup->sm_s_pres); 1795 if (IS_RESPONDER(sm_conn->sm_role)){ 1796 // responder 1797 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_rb, iocap_a, bd_addr_master, bd_addr_slave); 1798 f6_engine(sm_conn, setup->sm_mackey); 1799 } else { 1800 // initiator 1801 f6_setup(setup->sm_peer_nonce, setup->sm_local_nonce, setup->sm_ra, iocap_b, bd_addr_slave, bd_addr_master); 1802 f6_engine(sm_conn, setup->sm_mackey); 1803 } 1804 } 1805 1806 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 1807 1808 // 1809 // Link Key Conversion Function h6 1810 // 1811 // h6(W, keyID) = AES-CMAC_W(keyID) 1812 // - W is 128 bits 1813 // - keyID is 32 bits 1814 static void h6_engine(sm_connection_t * sm_conn, const sm_key_t w, const uint32_t key_id){ 1815 const uint16_t message_len = 4; 1816 sm_cmac_connection = sm_conn; 1817 big_endian_store_32(sm_cmac_sc_buffer, 0, key_id); 1818 log_info("h6 key"); 1819 log_info_hexdump(w, 16); 1820 log_info("h6 message"); 1821 log_info_hexdump(sm_cmac_sc_buffer, message_len); 1822 sm_cmac_message_start(w, message_len, sm_cmac_sc_buffer, &sm_sc_cmac_done); 1823 } 1824 // 1825 // Link Key Conversion Function h7 1826 // 1827 // h7(SALT, W) = AES-CMAC_SALT(W) 1828 // - SALT is 128 bits 1829 // - W is 128 bits 1830 static void h7_engine(sm_connection_t * sm_conn, const sm_key_t salt, const sm_key_t w) { 1831 const uint16_t message_len = 16; 1832 sm_cmac_connection = sm_conn; 1833 log_info("h7 key"); 1834 log_info_hexdump(salt, 16); 1835 log_info("h7 message"); 1836 log_info_hexdump(w, 16); 1837 sm_cmac_message_start(salt, message_len, w, &sm_sc_cmac_done); 1838 } 1839 1840 // For SC, setup->sm_local_ltk holds full LTK (sm_ltk is already truncated) 1841 // Errata Service Release to the Bluetooth Specification: ESR09 1842 // E6405 – Cross transport key derivation from a key of size less than 128 bits 1843 // "Note: When the BR/EDR link key is being derived from the LTK, the derivation is done before the LTK gets masked." 1844 1845 static void h6_calculate_ilk(sm_connection_t * sm_conn){ 1846 h6_engine(sm_conn, setup->sm_local_ltk, 0x746D7031); // "tmp1" 1847 } 1848 1849 static void h6_calculate_br_edr_link_key(sm_connection_t * sm_conn){ 1850 h6_engine(sm_conn, setup->sm_t, 0x6c656272); // "lebr" 1851 } 1852 1853 static void h7_calculate_ilk(sm_connection_t * sm_conn){ 1854 const uint8_t salt[16] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x74, 0x6D, 0x70, 0x31}; // "tmp1" 1855 h7_engine(sm_conn, salt, setup->sm_local_ltk); 1856 } 1857 #endif 1858 1859 #endif 1860 1861 // key management legacy connections: 1862 // - potentially two different LTKs based on direction. each device stores LTK provided by peer 1863 // - master stores LTK, EDIV, RAND. responder optionally stored master LTK (only if it needs to reconnect) 1864 // - initiators reconnects: initiator uses stored LTK, EDIV, RAND generated by responder 1865 // - responder reconnects: responder uses LTK receveived from master 1866 1867 // key management secure connections: 1868 // - both devices store same LTK from ECDH key exchange. 1869 1870 #if defined(ENABLE_LE_SECURE_CONNECTIONS) || defined(ENABLE_LE_CENTRAL) 1871 static void sm_load_security_info(sm_connection_t * sm_connection){ 1872 int encryption_key_size; 1873 int authenticated; 1874 int authorized; 1875 int secure_connection; 1876 1877 // fetch data from device db - incl. authenticated/authorized/key size. Note all sm_connection_X require encryption enabled 1878 le_device_db_encryption_get(sm_connection->sm_le_db_index, &setup->sm_peer_ediv, setup->sm_peer_rand, setup->sm_peer_ltk, 1879 &encryption_key_size, &authenticated, &authorized, &secure_connection); 1880 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); 1881 sm_connection->sm_actual_encryption_key_size = encryption_key_size; 1882 sm_connection->sm_connection_authenticated = authenticated; 1883 sm_connection->sm_connection_authorization_state = authorized ? AUTHORIZATION_GRANTED : AUTHORIZATION_UNKNOWN; 1884 sm_connection->sm_connection_sc = secure_connection; 1885 } 1886 #endif 1887 1888 #ifdef ENABLE_LE_PERIPHERAL 1889 static void sm_start_calculating_ltk_from_ediv_and_rand(sm_connection_t * sm_connection){ 1890 (void)memcpy(setup->sm_local_rand, sm_connection->sm_local_rand, 8); 1891 setup->sm_local_ediv = sm_connection->sm_local_ediv; 1892 // re-establish used key encryption size 1893 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 1894 sm_connection->sm_actual_encryption_key_size = (setup->sm_local_rand[7u] & 0x0fu) + 1u; 1895 // no db for authenticated flag hack: flag is stored in bit 4 of LSB 1896 sm_connection->sm_connection_authenticated = (setup->sm_local_rand[7u] & 0x10u) >> 4u; 1897 // Legacy paring -> not SC 1898 sm_connection->sm_connection_sc = 0; 1899 log_info("sm: received ltk request with key size %u, authenticated %u", 1900 sm_connection->sm_actual_encryption_key_size, sm_connection->sm_connection_authenticated); 1901 sm_connection->sm_engine_state = SM_RESPONDER_PH4_Y_GET_ENC; 1902 sm_trigger_run(); 1903 } 1904 #endif 1905 1906 // distributed key generation 1907 static bool sm_run_dpkg(void){ 1908 switch (dkg_state){ 1909 case DKG_CALC_IRK: 1910 // already busy? 1911 if (sm_aes128_state == SM_AES128_IDLE) { 1912 log_info("DKG_CALC_IRK started"); 1913 // IRK = d1(IR, 1, 0) 1914 sm_d1_d_prime(1, 0, sm_aes128_plaintext); // plaintext = d1 prime 1915 sm_aes128_state = SM_AES128_ACTIVE; 1916 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_irk, sm_handle_encryption_result_dkg_irk, NULL); 1917 return true; 1918 } 1919 break; 1920 case DKG_CALC_DHK: 1921 // already busy? 1922 if (sm_aes128_state == SM_AES128_IDLE) { 1923 log_info("DKG_CALC_DHK started"); 1924 // DHK = d1(IR, 3, 0) 1925 sm_d1_d_prime(3, 0, sm_aes128_plaintext); // plaintext = d1 prime 1926 sm_aes128_state = SM_AES128_ACTIVE; 1927 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_ir, sm_aes128_plaintext, sm_persistent_dhk, sm_handle_encryption_result_dkg_dhk, NULL); 1928 return true; 1929 } 1930 break; 1931 default: 1932 break; 1933 } 1934 return false; 1935 } 1936 1937 // random address updates 1938 static bool sm_run_rau(void){ 1939 switch (rau_state){ 1940 case RAU_GET_RANDOM: 1941 rau_state = RAU_W4_RANDOM; 1942 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_address, 6, &sm_handle_random_result_rau, NULL); 1943 return true; 1944 case RAU_GET_ENC: 1945 // already busy? 1946 if (sm_aes128_state == SM_AES128_IDLE) { 1947 sm_ah_r_prime(sm_random_address, sm_aes128_plaintext); 1948 sm_aes128_state = SM_AES128_ACTIVE; 1949 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_irk, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_rau, NULL); 1950 return true; 1951 } 1952 break; 1953 case RAU_SET_ADDRESS: 1954 log_info("New random address: %s", bd_addr_to_str(sm_random_address)); 1955 rau_state = RAU_IDLE; 1956 hci_send_cmd(&hci_le_set_random_address, sm_random_address); 1957 return true; 1958 default: 1959 break; 1960 } 1961 return false; 1962 } 1963 1964 // CSRK Lookup 1965 static bool sm_run_csrk(void){ 1966 btstack_linked_list_iterator_t it; 1967 1968 // -- if csrk lookup ready, find connection that require csrk lookup 1969 if (sm_address_resolution_idle()){ 1970 hci_connections_get_iterator(&it); 1971 while(btstack_linked_list_iterator_has_next(&it)){ 1972 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 1973 sm_connection_t * sm_connection = &hci_connection->sm_connection; 1974 if (sm_connection->sm_irk_lookup_state == IRK_LOOKUP_W4_READY){ 1975 // and start lookup 1976 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); 1977 sm_connection->sm_irk_lookup_state = IRK_LOOKUP_STARTED; 1978 break; 1979 } 1980 } 1981 } 1982 1983 // -- if csrk lookup ready, resolved addresses for received addresses 1984 if (sm_address_resolution_idle()) { 1985 if (!btstack_linked_list_empty(&sm_address_resolution_general_queue)){ 1986 sm_lookup_entry_t * entry = (sm_lookup_entry_t *) sm_address_resolution_general_queue; 1987 btstack_linked_list_remove(&sm_address_resolution_general_queue, (btstack_linked_item_t *) entry); 1988 sm_address_resolution_start_lookup(entry->address_type, 0, entry->address, ADDRESS_RESOLUTION_GENERAL, NULL); 1989 btstack_memory_sm_lookup_entry_free(entry); 1990 } 1991 } 1992 1993 // -- Continue with CSRK device lookup by public or resolvable private address 1994 if (!sm_address_resolution_idle()){ 1995 log_info("LE Device Lookup: device %u/%u", sm_address_resolution_test, le_device_db_max_count()); 1996 while (sm_address_resolution_test < le_device_db_max_count()){ 1997 int addr_type = BD_ADDR_TYPE_UNKNOWN; 1998 bd_addr_t addr; 1999 sm_key_t irk; 2000 le_device_db_info(sm_address_resolution_test, &addr_type, addr, irk); 2001 log_info("device type %u, addr: %s", addr_type, bd_addr_to_str(addr)); 2002 2003 // skip unused entries 2004 if (addr_type == BD_ADDR_TYPE_UNKNOWN){ 2005 sm_address_resolution_test++; 2006 continue; 2007 } 2008 2009 if ((sm_address_resolution_addr_type == addr_type) && (memcmp(addr, sm_address_resolution_address, 6) == 0)){ 2010 log_info("LE Device Lookup: found CSRK by { addr_type, address} "); 2011 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 2012 break; 2013 } 2014 2015 // if connection type is public, it must be a different one 2016 if (sm_address_resolution_addr_type == BD_ADDR_TYPE_LE_PUBLIC){ 2017 sm_address_resolution_test++; 2018 continue; 2019 } 2020 2021 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2022 2023 log_info("LE Device Lookup: calculate AH"); 2024 log_info_key("IRK", irk); 2025 2026 (void)memcpy(sm_aes128_key, irk, 16); 2027 sm_ah_r_prime(sm_address_resolution_address, sm_aes128_plaintext); 2028 sm_address_resolution_ah_calculation_active = 1; 2029 sm_aes128_state = SM_AES128_ACTIVE; 2030 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_aes128_key, sm_aes128_plaintext, sm_aes128_ciphertext, sm_handle_encryption_result_address_resolution, NULL); 2031 return true; 2032 } 2033 2034 if (sm_address_resolution_test >= le_device_db_max_count()){ 2035 log_info("LE Device Lookup: not found"); 2036 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_FAILED); 2037 } 2038 } 2039 return false; 2040 } 2041 2042 // SC OOB 2043 static bool sm_run_oob(void){ 2044 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2045 switch (sm_sc_oob_state){ 2046 case SM_SC_OOB_W2_CALC_CONFIRM: 2047 if (!sm_cmac_ready()) break; 2048 sm_sc_oob_state = SM_SC_OOB_W4_CONFIRM; 2049 f4_engine(NULL, ec_q, ec_q, sm_sc_oob_random, 0); 2050 return true; 2051 default: 2052 break; 2053 } 2054 #endif 2055 return false; 2056 } 2057 2058 // handle basic actions that don't requires the full context 2059 static bool sm_run_basic(void){ 2060 btstack_linked_list_iterator_t it; 2061 hci_connections_get_iterator(&it); 2062 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2063 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2064 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2065 switch(sm_connection->sm_engine_state){ 2066 // responder side 2067 case SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY: 2068 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2069 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2070 return true; 2071 2072 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2073 case SM_SC_RECEIVED_LTK_REQUEST: 2074 switch (sm_connection->sm_irk_lookup_state){ 2075 case IRK_LOOKUP_FAILED: 2076 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Failed)"); 2077 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2078 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2079 return true; 2080 default: 2081 break; 2082 } 2083 break; 2084 #endif 2085 default: 2086 break; 2087 } 2088 } 2089 return false; 2090 } 2091 2092 static void sm_run_activate_connection(void){ 2093 // Find connections that requires setup context and make active if no other is locked 2094 btstack_linked_list_iterator_t it; 2095 hci_connections_get_iterator(&it); 2096 while((sm_active_connection_handle == HCI_CON_HANDLE_INVALID) && btstack_linked_list_iterator_has_next(&it)){ 2097 hci_connection_t * hci_connection = (hci_connection_t *) btstack_linked_list_iterator_next(&it); 2098 sm_connection_t * sm_connection = &hci_connection->sm_connection; 2099 // - if no connection locked and we're ready/waiting for setup context, fetch it and start 2100 int done = 1; 2101 int err; 2102 UNUSED(err); 2103 2104 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2105 // assert ec key is ready 2106 if ((sm_connection->sm_engine_state == SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED) 2107 || (sm_connection->sm_engine_state == SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST)){ 2108 if (ec_key_generation_state == EC_KEY_GENERATION_IDLE){ 2109 sm_ec_generate_new_key(); 2110 } 2111 if (ec_key_generation_state != EC_KEY_GENERATION_DONE){ 2112 continue; 2113 } 2114 } 2115 #endif 2116 2117 switch (sm_connection->sm_engine_state) { 2118 #ifdef ENABLE_LE_PERIPHERAL 2119 case SM_RESPONDER_SEND_SECURITY_REQUEST: 2120 // send packet if possible, 2121 if (l2cap_can_send_fixed_channel_packet_now(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)){ 2122 const uint8_t buffer[2] = { SM_CODE_SECURITY_REQUEST, sm_auth_req}; 2123 sm_connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_REQUEST; 2124 l2cap_send_connectionless(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2125 } else { 2126 l2cap_request_can_send_fix_channel_now_event(sm_connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2127 } 2128 // don't lock sxetup context yet 2129 done = 0; 2130 break; 2131 case SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED: 2132 sm_reset_setup(); 2133 sm_init_setup(sm_connection); 2134 // recover pairing request 2135 (void)memcpy(&setup->sm_m_preq, 2136 &sm_connection->sm_m_preq, 2137 sizeof(sm_pairing_packet_t)); 2138 err = sm_stk_generation_init(sm_connection); 2139 2140 #ifdef ENABLE_TESTING_SUPPORT 2141 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 2142 log_info("testing_support: respond with pairing failure %u", test_pairing_failure); 2143 err = test_pairing_failure; 2144 } 2145 #endif 2146 if (err){ 2147 setup->sm_pairing_failed_reason = err; 2148 sm_connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2149 break; 2150 } 2151 sm_timeout_start(sm_connection); 2152 // generate random number first, if we need to show passkey 2153 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 2154 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 8, &sm_handle_random_result_ph2_tk, (void *)(uintptr_t) sm_connection->sm_handle); 2155 break; 2156 } 2157 sm_connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 2158 break; 2159 case SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST: 2160 sm_reset_setup(); 2161 sm_start_calculating_ltk_from_ediv_and_rand(sm_connection); 2162 break; 2163 2164 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2165 case SM_SC_RECEIVED_LTK_REQUEST: 2166 switch (sm_connection->sm_irk_lookup_state){ 2167 case IRK_LOOKUP_SUCCEEDED: 2168 // assuming Secure Connection, we have a stored LTK and the EDIV/RAND are null 2169 // start using context by loading security info 2170 sm_reset_setup(); 2171 sm_load_security_info(sm_connection); 2172 if ((setup->sm_peer_ediv == 0u) && sm_is_null_random(setup->sm_peer_rand) && !sm_is_null_key(setup->sm_peer_ltk)){ 2173 (void)memcpy(setup->sm_ltk, 2174 setup->sm_peer_ltk, 16); 2175 sm_connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 2176 break; 2177 } 2178 log_info("LTK Request: ediv & random are empty, but no stored LTK (IRK Lookup Succeeded)"); 2179 sm_connection->sm_engine_state = SM_RESPONDER_IDLE; 2180 hci_send_cmd(&hci_le_long_term_key_negative_reply, sm_connection->sm_handle); 2181 // don't lock setup context yet 2182 return; 2183 default: 2184 // just wait until IRK lookup is completed 2185 // don't lock setup context yet 2186 done = 0; 2187 break; 2188 } 2189 break; 2190 #endif /* ENABLE_LE_SECURE_CONNECTIONS */ 2191 #endif /* ENABLE_LE_PERIPHERAL */ 2192 2193 #ifdef ENABLE_LE_CENTRAL 2194 case SM_INITIATOR_PH0_HAS_LTK: 2195 sm_reset_setup(); 2196 sm_load_security_info(sm_connection); 2197 sm_connection->sm_engine_state = SM_INITIATOR_PH0_SEND_START_ENCRYPTION; 2198 break; 2199 case SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST: 2200 sm_reset_setup(); 2201 sm_init_setup(sm_connection); 2202 sm_timeout_start(sm_connection); 2203 sm_connection->sm_engine_state = SM_INITIATOR_PH1_SEND_PAIRING_REQUEST; 2204 break; 2205 #endif 2206 2207 default: 2208 done = 0; 2209 break; 2210 } 2211 if (done){ 2212 sm_active_connection_handle = sm_connection->sm_handle; 2213 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); 2214 } 2215 } 2216 } 2217 2218 static void sm_run(void){ 2219 2220 // assert that stack has already bootet 2221 if (hci_get_state() != HCI_STATE_WORKING) return; 2222 2223 // assert that we can send at least commands 2224 if (!hci_can_send_command_packet_now()) return; 2225 2226 // pause until IR/ER are ready 2227 if (sm_persistent_keys_random_active) return; 2228 2229 bool done; 2230 2231 // 2232 // non-connection related behaviour 2233 // 2234 2235 done = sm_run_dpkg(); 2236 if (done) return; 2237 2238 done = sm_run_rau(); 2239 if (done) return; 2240 2241 done = sm_run_csrk(); 2242 if (done) return; 2243 2244 done = sm_run_oob(); 2245 if (done) return; 2246 2247 // assert that we can send at least commands - cmd might have been sent by crypto engine 2248 if (!hci_can_send_command_packet_now()) return; 2249 2250 // handle basic actions that don't requires the full context 2251 done = sm_run_basic(); 2252 if (done) return; 2253 2254 // 2255 // active connection handling 2256 // -- use loop to handle next connection if lock on setup context is released 2257 2258 while (true) { 2259 2260 sm_run_activate_connection(); 2261 2262 if (sm_active_connection_handle == HCI_CON_HANDLE_INVALID) return; 2263 2264 // 2265 // active connection handling 2266 // 2267 2268 sm_connection_t * connection = sm_get_connection_for_handle(sm_active_connection_handle); 2269 if (!connection) { 2270 log_info("no connection for handle 0x%04x", sm_active_connection_handle); 2271 return; 2272 } 2273 2274 // assert that we could send a SM PDU - not needed for all of the following 2275 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2276 log_info("cannot send now, requesting can send now event"); 2277 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2278 return; 2279 } 2280 2281 // send keypress notifications 2282 if (setup->sm_keypress_notification){ 2283 int i; 2284 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 2285 uint8_t num_actions = setup->sm_keypress_notification >> 5; 2286 uint8_t action = 0; 2287 for (i=SM_KEYPRESS_PASSKEY_ENTRY_STARTED;i<=SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED;i++){ 2288 if (flags & (1u<<i)){ 2289 int clear_flag = 1; 2290 switch (i){ 2291 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 2292 case SM_KEYPRESS_PASSKEY_CLEARED: 2293 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 2294 default: 2295 break; 2296 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 2297 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 2298 num_actions--; 2299 clear_flag = num_actions == 0u; 2300 break; 2301 } 2302 if (clear_flag){ 2303 flags &= ~(1<<i); 2304 } 2305 action = i; 2306 break; 2307 } 2308 } 2309 setup->sm_keypress_notification = (num_actions << 5) | flags; 2310 2311 // send keypress notification 2312 uint8_t buffer[2]; 2313 buffer[0] = SM_CODE_KEYPRESS_NOTIFICATION; 2314 buffer[1] = action; 2315 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2316 2317 // try 2318 l2cap_request_can_send_fix_channel_now_event(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 2319 return; 2320 } 2321 2322 int key_distribution_flags; 2323 UNUSED(key_distribution_flags); 2324 2325 log_info("sm_run: state %u", connection->sm_engine_state); 2326 if (!l2cap_can_send_fixed_channel_packet_now(sm_active_connection_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL)) { 2327 log_info("sm_run // cannot send"); 2328 } 2329 switch (connection->sm_engine_state){ 2330 2331 // general 2332 case SM_GENERAL_SEND_PAIRING_FAILED: { 2333 uint8_t buffer[2]; 2334 buffer[0] = SM_CODE_PAIRING_FAILED; 2335 buffer[1] = setup->sm_pairing_failed_reason; 2336 connection->sm_engine_state = connection->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 2337 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2338 sm_notify_client_status_reason(connection, ERROR_CODE_AUTHENTICATION_FAILURE, setup->sm_pairing_failed_reason); 2339 sm_done_for_handle(connection->sm_handle); 2340 break; 2341 } 2342 2343 // responding state 2344 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2345 case SM_SC_W2_CMAC_FOR_CONFIRMATION: 2346 if (!sm_cmac_ready()) break; 2347 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CONFIRMATION; 2348 sm_sc_calculate_local_confirm(connection); 2349 break; 2350 case SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION: 2351 if (!sm_cmac_ready()) break; 2352 connection->sm_engine_state = SM_SC_W4_CMAC_FOR_CHECK_CONFIRMATION; 2353 sm_sc_calculate_remote_confirm(connection); 2354 break; 2355 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 2356 if (!sm_cmac_ready()) break; 2357 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK; 2358 sm_sc_calculate_f6_for_dhkey_check(connection); 2359 break; 2360 case SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK: 2361 if (!sm_cmac_ready()) break; 2362 connection->sm_engine_state = SM_SC_W4_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 2363 sm_sc_calculate_f6_to_verify_dhkey_check(connection); 2364 break; 2365 case SM_SC_W2_CALCULATE_F5_SALT: 2366 if (!sm_cmac_ready()) break; 2367 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_SALT; 2368 f5_calculate_salt(connection); 2369 break; 2370 case SM_SC_W2_CALCULATE_F5_MACKEY: 2371 if (!sm_cmac_ready()) break; 2372 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_MACKEY; 2373 f5_calculate_mackey(connection); 2374 break; 2375 case SM_SC_W2_CALCULATE_F5_LTK: 2376 if (!sm_cmac_ready()) break; 2377 connection->sm_engine_state = SM_SC_W4_CALCULATE_F5_LTK; 2378 f5_calculate_ltk(connection); 2379 break; 2380 case SM_SC_W2_CALCULATE_G2: 2381 if (!sm_cmac_ready()) break; 2382 connection->sm_engine_state = SM_SC_W4_CALCULATE_G2; 2383 g2_calculate(connection); 2384 break; 2385 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2386 case SM_SC_W2_CALCULATE_ILK_USING_H6: 2387 if (!sm_cmac_ready()) break; 2388 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 2389 h6_calculate_ilk(connection); 2390 break; 2391 case SM_SC_W2_CALCULATE_BR_EDR_LINK_KEY: 2392 if (!sm_cmac_ready()) break; 2393 connection->sm_engine_state = SM_SC_W4_CALCULATE_BR_EDR_LINK_KEY; 2394 h6_calculate_br_edr_link_key(connection); 2395 break; 2396 case SM_SC_W2_CALCULATE_ILK_USING_H7: 2397 if (!sm_cmac_ready()) break; 2398 connection->sm_engine_state = SM_SC_W4_CALCULATE_ILK; 2399 h7_calculate_ilk(connection); 2400 break; 2401 #endif 2402 #endif 2403 2404 #ifdef ENABLE_LE_CENTRAL 2405 // initiator side 2406 case SM_INITIATOR_PH0_SEND_START_ENCRYPTION: { 2407 sm_key_t peer_ltk_flipped; 2408 reverse_128(setup->sm_peer_ltk, peer_ltk_flipped); 2409 connection->sm_engine_state = SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED; 2410 log_info("sm: hci_le_start_encryption ediv 0x%04x", setup->sm_peer_ediv); 2411 uint32_t rand_high = big_endian_read_32(setup->sm_peer_rand, 0); 2412 uint32_t rand_low = big_endian_read_32(setup->sm_peer_rand, 4); 2413 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle,rand_low, rand_high, setup->sm_peer_ediv, peer_ltk_flipped); 2414 return; 2415 } 2416 2417 case SM_INITIATOR_PH1_SEND_PAIRING_REQUEST: 2418 sm_pairing_packet_set_code(setup->sm_m_preq, SM_CODE_PAIRING_REQUEST); 2419 connection->sm_engine_state = SM_INITIATOR_PH1_W4_PAIRING_RESPONSE; 2420 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_m_preq, sizeof(sm_pairing_packet_t)); 2421 sm_timeout_reset(connection); 2422 break; 2423 #endif 2424 2425 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2426 2427 case SM_SC_SEND_PUBLIC_KEY_COMMAND: { 2428 int trigger_user_response = 0; 2429 int trigger_start_calculating_local_confirm = 0; 2430 uint8_t buffer[65]; 2431 buffer[0] = SM_CODE_PAIRING_PUBLIC_KEY; 2432 // 2433 reverse_256(&ec_q[0], &buffer[1]); 2434 reverse_256(&ec_q[32], &buffer[33]); 2435 2436 #ifdef ENABLE_TESTING_SUPPORT 2437 if (test_pairing_failure == SM_REASON_DHKEY_CHECK_FAILED){ 2438 log_info("testing_support: invalidating public key"); 2439 // flip single bit of public key coordinate 2440 buffer[1] ^= 1; 2441 } 2442 #endif 2443 2444 // stk generation method 2445 // passkey entry: notify app to show passkey or to request passkey 2446 switch (setup->sm_stk_generation_method){ 2447 case JUST_WORKS: 2448 case NUMERIC_COMPARISON: 2449 if (IS_RESPONDER(connection->sm_role)){ 2450 // responder 2451 trigger_start_calculating_local_confirm = 1; 2452 connection->sm_engine_state = SM_SC_W4_LOCAL_NONCE; 2453 } else { 2454 // initiator 2455 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2456 } 2457 break; 2458 case PK_INIT_INPUT: 2459 case PK_RESP_INPUT: 2460 case PK_BOTH_INPUT: 2461 // use random TK for display 2462 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 2463 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 2464 setup->sm_passkey_bit = 0; 2465 2466 if (IS_RESPONDER(connection->sm_role)){ 2467 // responder 2468 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2469 } else { 2470 // initiator 2471 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2472 } 2473 trigger_user_response = 1; 2474 break; 2475 case OOB: 2476 if (IS_RESPONDER(connection->sm_role)){ 2477 // responder 2478 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2479 } else { 2480 // initiator 2481 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2482 } 2483 break; 2484 } 2485 2486 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2487 sm_timeout_reset(connection); 2488 2489 // trigger user response and calc confirm after sending pdu 2490 if (trigger_user_response){ 2491 sm_trigger_user_response(connection); 2492 } 2493 if (trigger_start_calculating_local_confirm){ 2494 sm_sc_start_calculating_local_confirm(connection); 2495 } 2496 break; 2497 } 2498 case SM_SC_SEND_CONFIRMATION: { 2499 uint8_t buffer[17]; 2500 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2501 reverse_128(setup->sm_local_confirm, &buffer[1]); 2502 if (IS_RESPONDER(connection->sm_role)){ 2503 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2504 } else { 2505 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2506 } 2507 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2508 sm_timeout_reset(connection); 2509 break; 2510 } 2511 case SM_SC_SEND_PAIRING_RANDOM: { 2512 uint8_t buffer[17]; 2513 buffer[0] = SM_CODE_PAIRING_RANDOM; 2514 reverse_128(setup->sm_local_nonce, &buffer[1]); 2515 log_info("stk method %u, num bits %u", setup->sm_stk_generation_method, setup->sm_passkey_bit); 2516 if (sm_passkey_entry(setup->sm_stk_generation_method) && (setup->sm_passkey_bit < 20u)){ 2517 log_info("SM_SC_SEND_PAIRING_RANDOM A"); 2518 if (IS_RESPONDER(connection->sm_role)){ 2519 // responder 2520 connection->sm_engine_state = SM_SC_W4_CONFIRMATION; 2521 } else { 2522 // initiator 2523 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2524 } 2525 } else { 2526 log_info("SM_SC_SEND_PAIRING_RANDOM B"); 2527 if (IS_RESPONDER(connection->sm_role)){ 2528 // responder 2529 if (setup->sm_stk_generation_method == NUMERIC_COMPARISON){ 2530 log_info("SM_SC_SEND_PAIRING_RANDOM B1"); 2531 connection->sm_engine_state = SM_SC_W2_CALCULATE_G2; 2532 } else { 2533 log_info("SM_SC_SEND_PAIRING_RANDOM B2"); 2534 sm_sc_prepare_dhkey_check(connection); 2535 } 2536 } else { 2537 // initiator 2538 connection->sm_engine_state = SM_SC_W4_PAIRING_RANDOM; 2539 } 2540 } 2541 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2542 sm_timeout_reset(connection); 2543 break; 2544 } 2545 case SM_SC_SEND_DHKEY_CHECK_COMMAND: { 2546 uint8_t buffer[17]; 2547 buffer[0] = SM_CODE_PAIRING_DHKEY_CHECK; 2548 reverse_128(setup->sm_local_dhkey_check, &buffer[1]); 2549 2550 if (IS_RESPONDER(connection->sm_role)){ 2551 connection->sm_engine_state = SM_SC_W4_LTK_REQUEST_SC; 2552 } else { 2553 connection->sm_engine_state = SM_SC_W4_DHKEY_CHECK_COMMAND; 2554 } 2555 2556 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2557 sm_timeout_reset(connection); 2558 break; 2559 } 2560 2561 #endif 2562 2563 #ifdef ENABLE_LE_PERIPHERAL 2564 case SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE: 2565 sm_pairing_packet_set_code(setup->sm_s_pres,SM_CODE_PAIRING_RESPONSE); 2566 2567 // start with initiator key dist flags 2568 key_distribution_flags = sm_key_distribution_flags_for_auth_req(); 2569 2570 #ifdef ENABLE_LE_SECURE_CONNECTIONS 2571 // LTK (= encyrption information & master identification) only exchanged for LE Legacy Connection 2572 if (setup->sm_use_secure_connections){ 2573 key_distribution_flags &= ~SM_KEYDIST_ENC_KEY; 2574 } 2575 #endif 2576 // setup in response 2577 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); 2578 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); 2579 2580 // update key distribution after ENC was dropped 2581 sm_setup_key_distribution(sm_pairing_packet_get_responder_key_distribution(setup->sm_s_pres)); 2582 2583 if (setup->sm_use_secure_connections){ 2584 connection->sm_engine_state = SM_SC_W4_PUBLIC_KEY_COMMAND; 2585 } else { 2586 connection->sm_engine_state = SM_RESPONDER_PH1_W4_PAIRING_CONFIRM; 2587 } 2588 2589 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) &setup->sm_s_pres, sizeof(sm_pairing_packet_t)); 2590 sm_timeout_reset(connection); 2591 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 2592 if (!setup->sm_use_secure_connections || (setup->sm_stk_generation_method == JUST_WORKS)){ 2593 sm_trigger_user_response(connection); 2594 } 2595 return; 2596 #endif 2597 2598 case SM_PH2_SEND_PAIRING_RANDOM: { 2599 uint8_t buffer[17]; 2600 buffer[0] = SM_CODE_PAIRING_RANDOM; 2601 reverse_128(setup->sm_local_random, &buffer[1]); 2602 if (IS_RESPONDER(connection->sm_role)){ 2603 connection->sm_engine_state = SM_RESPONDER_PH2_W4_LTK_REQUEST; 2604 } else { 2605 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_RANDOM; 2606 } 2607 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2608 sm_timeout_reset(connection); 2609 break; 2610 } 2611 2612 case SM_PH2_C1_GET_ENC_A: 2613 // already busy? 2614 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2615 // calculate confirm using aes128 engine - step 1 2616 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); 2617 connection->sm_engine_state = SM_PH2_C1_W4_ENC_A; 2618 sm_aes128_state = SM_AES128_ACTIVE; 2619 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); 2620 break; 2621 2622 case SM_PH2_C1_GET_ENC_C: 2623 // already busy? 2624 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2625 // calculate m_confirm using aes128 engine - step 1 2626 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); 2627 connection->sm_engine_state = SM_PH2_C1_W4_ENC_C; 2628 sm_aes128_state = SM_AES128_ACTIVE; 2629 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); 2630 break; 2631 2632 case SM_PH2_CALC_STK: 2633 // already busy? 2634 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2635 // calculate STK 2636 if (IS_RESPONDER(connection->sm_role)){ 2637 sm_s1_r_prime(setup->sm_local_random, setup->sm_peer_random, sm_aes128_plaintext); 2638 } else { 2639 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2640 } 2641 connection->sm_engine_state = SM_PH2_W4_STK; 2642 sm_aes128_state = SM_AES128_ACTIVE; 2643 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); 2644 break; 2645 2646 case SM_PH3_Y_GET_ENC: 2647 // already busy? 2648 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2649 // PH3B2 - calculate Y from - enc 2650 2651 // dm helper (was sm_dm_r_prime) 2652 // r' = padding || r 2653 // r - 64 bit value 2654 memset(&sm_aes128_plaintext[0], 0, 8); 2655 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2656 2657 // Y = dm(DHK, Rand) 2658 connection->sm_engine_state = SM_PH3_Y_W4_ENC; 2659 sm_aes128_state = SM_AES128_ACTIVE; 2660 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); 2661 break; 2662 2663 case SM_PH2_C1_SEND_PAIRING_CONFIRM: { 2664 uint8_t buffer[17]; 2665 buffer[0] = SM_CODE_PAIRING_CONFIRM; 2666 reverse_128(setup->sm_local_confirm, &buffer[1]); 2667 if (IS_RESPONDER(connection->sm_role)){ 2668 connection->sm_engine_state = SM_RESPONDER_PH2_W4_PAIRING_RANDOM; 2669 } else { 2670 connection->sm_engine_state = SM_INITIATOR_PH2_W4_PAIRING_CONFIRM; 2671 } 2672 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2673 sm_timeout_reset(connection); 2674 return; 2675 } 2676 #ifdef ENABLE_LE_PERIPHERAL 2677 case SM_RESPONDER_PH2_SEND_LTK_REPLY: { 2678 sm_key_t stk_flipped; 2679 reverse_128(setup->sm_ltk, stk_flipped); 2680 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2681 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, stk_flipped); 2682 return; 2683 } 2684 case SM_RESPONDER_PH4_SEND_LTK_REPLY: { 2685 sm_key_t ltk_flipped; 2686 reverse_128(setup->sm_ltk, ltk_flipped); 2687 connection->sm_engine_state = SM_RESPONDER_IDLE; 2688 hci_send_cmd(&hci_le_long_term_key_request_reply, connection->sm_handle, ltk_flipped); 2689 sm_done_for_handle(connection->sm_handle); 2690 return; 2691 } 2692 case SM_RESPONDER_PH4_Y_GET_ENC: 2693 // already busy? 2694 if (sm_aes128_state == SM_AES128_ACTIVE) break; 2695 log_info("LTK Request: recalculating with ediv 0x%04x", setup->sm_local_ediv); 2696 2697 // dm helper (was sm_dm_r_prime) 2698 // r' = padding || r 2699 // r - 64 bit value 2700 memset(&sm_aes128_plaintext[0], 0, 8); 2701 (void)memcpy(&sm_aes128_plaintext[8], setup->sm_local_rand, 8); 2702 2703 // Y = dm(DHK, Rand) 2704 connection->sm_engine_state = SM_RESPONDER_PH4_Y_W4_ENC; 2705 sm_aes128_state = SM_AES128_ACTIVE; 2706 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); 2707 return; 2708 #endif 2709 #ifdef ENABLE_LE_CENTRAL 2710 case SM_INITIATOR_PH3_SEND_START_ENCRYPTION: { 2711 sm_key_t stk_flipped; 2712 reverse_128(setup->sm_ltk, stk_flipped); 2713 connection->sm_engine_state = SM_PH2_W4_CONNECTION_ENCRYPTED; 2714 hci_send_cmd(&hci_le_start_encryption, connection->sm_handle, 0, 0, 0, stk_flipped); 2715 return; 2716 } 2717 #endif 2718 2719 case SM_PH3_DISTRIBUTE_KEYS: 2720 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION){ 2721 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2722 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 2723 uint8_t buffer[17]; 2724 buffer[0] = SM_CODE_ENCRYPTION_INFORMATION; 2725 reverse_128(setup->sm_ltk, &buffer[1]); 2726 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2727 sm_timeout_reset(connection); 2728 return; 2729 } 2730 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_MASTER_IDENTIFICATION){ 2731 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2732 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 2733 uint8_t buffer[11]; 2734 buffer[0] = SM_CODE_MASTER_IDENTIFICATION; 2735 little_endian_store_16(buffer, 1, setup->sm_local_ediv); 2736 reverse_64(setup->sm_local_rand, &buffer[3]); 2737 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2738 sm_timeout_reset(connection); 2739 return; 2740 } 2741 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_INFORMATION){ 2742 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2743 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 2744 uint8_t buffer[17]; 2745 buffer[0] = SM_CODE_IDENTITY_INFORMATION; 2746 reverse_128(sm_persistent_irk, &buffer[1]); 2747 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2748 sm_timeout_reset(connection); 2749 return; 2750 } 2751 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION){ 2752 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2753 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 2754 bd_addr_t local_address; 2755 uint8_t buffer[8]; 2756 buffer[0] = SM_CODE_IDENTITY_ADDRESS_INFORMATION; 2757 switch (gap_random_address_get_mode()){ 2758 case GAP_RANDOM_ADDRESS_TYPE_OFF: 2759 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 2760 // public or static random 2761 gap_le_get_own_address(&buffer[1], local_address); 2762 break; 2763 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 2764 case GAP_RANDOM_ADDRESS_RESOLVABLE: 2765 // fallback to public 2766 gap_local_bd_addr(local_address); 2767 buffer[1] = 0; 2768 break; 2769 } 2770 reverse_bd_addr(local_address, &buffer[2]); 2771 l2cap_send_connectionless(connection->sm_handle, L2CAP_CID_SECURITY_MANAGER_PROTOCOL, (uint8_t*) buffer, sizeof(buffer)); 2772 sm_timeout_reset(connection); 2773 return; 2774 } 2775 if (setup->sm_key_distribution_send_set & SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION){ 2776 setup->sm_key_distribution_send_set &= ~SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2777 setup->sm_key_distribution_sent_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 2778 2779 #ifdef ENABLE_LE_SIGNED_WRITE 2780 // hack to reproduce test runs 2781 if (test_use_fixed_local_csrk){ 2782 memset(setup->sm_local_csrk, 0xcc, 16); 2783 } 2784 2785 // store local CSRK 2786 if (setup->sm_le_device_index >= 0){ 2787 log_info("sm: store local CSRK"); 2788 le_device_db_local_csrk_set(setup->sm_le_device_index, setup->sm_local_csrk); 2789 le_device_db_local_counter_set(setup->sm_le_device_index, 0); 2790 } 2791 #endif 2792 2793 uint8_t buffer[17]; 2794 buffer[0] = SM_CODE_SIGNING_INFORMATION; 2795 reverse_128(setup->sm_local_csrk, &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 2801 // keys are sent 2802 if (IS_RESPONDER(connection->sm_role)){ 2803 // slave -> receive master keys if any 2804 if (sm_key_distribution_all_received(connection)){ 2805 sm_key_distribution_handle_all_received(connection); 2806 connection->sm_engine_state = SM_RESPONDER_IDLE; 2807 sm_notify_client_status_reason(connection, ERROR_CODE_SUCCESS, 0); 2808 sm_done_for_handle(connection->sm_handle); 2809 } else { 2810 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 2811 } 2812 } else { 2813 sm_master_pairing_success(connection); 2814 } 2815 break; 2816 2817 default: 2818 break; 2819 } 2820 2821 // check again if active connection was released 2822 if (sm_active_connection_handle != HCI_CON_HANDLE_INVALID) break; 2823 } 2824 } 2825 2826 // sm_aes128_state stays active 2827 static void sm_handle_encryption_result_enc_a(void *arg){ 2828 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2829 sm_aes128_state = SM_AES128_IDLE; 2830 2831 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2832 if (connection == NULL) return; 2833 2834 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2835 sm_aes128_state = SM_AES128_ACTIVE; 2836 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); 2837 } 2838 2839 static void sm_handle_encryption_result_enc_b(void *arg){ 2840 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2841 sm_aes128_state = SM_AES128_IDLE; 2842 2843 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2844 if (connection == NULL) return; 2845 2846 log_info_key("c1!", setup->sm_local_confirm); 2847 connection->sm_engine_state = SM_PH2_C1_SEND_PAIRING_CONFIRM; 2848 sm_trigger_run(); 2849 } 2850 2851 // sm_aes128_state stays active 2852 static void sm_handle_encryption_result_enc_c(void *arg){ 2853 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2854 sm_aes128_state = SM_AES128_IDLE; 2855 2856 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2857 if (connection == NULL) return; 2858 2859 sm_c1_t3(sm_aes128_ciphertext, setup->sm_m_address, setup->sm_s_address, setup->sm_c1_t3_value); 2860 sm_aes128_state = SM_AES128_ACTIVE; 2861 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); 2862 } 2863 2864 static void sm_handle_encryption_result_enc_d(void * arg){ 2865 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2866 sm_aes128_state = SM_AES128_IDLE; 2867 2868 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2869 if (connection == NULL) return; 2870 2871 log_info_key("c1!", sm_aes128_ciphertext); 2872 if (memcmp(setup->sm_peer_confirm, sm_aes128_ciphertext, 16) != 0){ 2873 setup->sm_pairing_failed_reason = SM_REASON_CONFIRM_VALUE_FAILED; 2874 connection->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 2875 sm_trigger_run(); 2876 return; 2877 } 2878 if (IS_RESPONDER(connection->sm_role)){ 2879 connection->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 2880 sm_trigger_run(); 2881 } else { 2882 sm_s1_r_prime(setup->sm_peer_random, setup->sm_local_random, sm_aes128_plaintext); 2883 sm_aes128_state = SM_AES128_ACTIVE; 2884 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); 2885 } 2886 } 2887 2888 static void sm_handle_encryption_result_enc_stk(void *arg){ 2889 sm_aes128_state = SM_AES128_IDLE; 2890 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2891 2892 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2893 if (connection == NULL) return; 2894 2895 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 2896 log_info_key("stk", setup->sm_ltk); 2897 if (IS_RESPONDER(connection->sm_role)){ 2898 connection->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 2899 } else { 2900 connection->sm_engine_state = SM_INITIATOR_PH3_SEND_START_ENCRYPTION; 2901 } 2902 sm_trigger_run(); 2903 } 2904 2905 // sm_aes128_state stays active 2906 static void sm_handle_encryption_result_enc_ph3_y(void *arg){ 2907 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2908 sm_aes128_state = SM_AES128_IDLE; 2909 2910 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2911 if (connection == NULL) return; 2912 2913 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2914 log_info_hex16("y", setup->sm_local_y); 2915 // PH3B3 - calculate EDIV 2916 setup->sm_local_ediv = setup->sm_local_y ^ setup->sm_local_div; 2917 log_info_hex16("ediv", setup->sm_local_ediv); 2918 // PH3B4 - calculate LTK - enc 2919 // LTK = d1(ER, DIV, 0)) 2920 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2921 sm_aes128_state = SM_AES128_ACTIVE; 2922 btstack_crypto_aes128_encrypt(&sm_crypto_aes128_request, sm_persistent_er, sm_aes128_plaintext, setup->sm_ltk, sm_handle_encryption_result_enc_ph3_ltk, (void *)(uintptr_t) connection->sm_handle); 2923 } 2924 2925 #ifdef ENABLE_LE_PERIPHERAL 2926 // sm_aes128_state stays active 2927 static void sm_handle_encryption_result_enc_ph4_y(void *arg){ 2928 sm_aes128_state = SM_AES128_IDLE; 2929 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2930 2931 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2932 if (connection == NULL) return; 2933 2934 setup->sm_local_y = big_endian_read_16(sm_aes128_ciphertext, 14); 2935 log_info_hex16("y", setup->sm_local_y); 2936 2937 // PH3B3 - calculate DIV 2938 setup->sm_local_div = setup->sm_local_y ^ setup->sm_local_ediv; 2939 log_info_hex16("ediv", setup->sm_local_ediv); 2940 // PH3B4 - calculate LTK - enc 2941 // LTK = d1(ER, DIV, 0)) 2942 sm_d1_d_prime(setup->sm_local_div, 0, sm_aes128_plaintext); 2943 sm_aes128_state = SM_AES128_ACTIVE; 2944 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); 2945 } 2946 #endif 2947 2948 // sm_aes128_state stays active 2949 static void sm_handle_encryption_result_enc_ph3_ltk(void *arg){ 2950 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2951 sm_aes128_state = SM_AES128_IDLE; 2952 2953 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2954 if (connection == NULL) return; 2955 2956 log_info_key("ltk", setup->sm_ltk); 2957 // calc CSRK next 2958 sm_d1_d_prime(setup->sm_local_div, 1, sm_aes128_plaintext); 2959 sm_aes128_state = SM_AES128_ACTIVE; 2960 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); 2961 } 2962 static bool sm_ctkd_from_le(sm_connection_t *sm_connection) { 2963 #ifdef ENABLE_CROSS_TRANSPORT_KEY_DERIVATION 2964 // requirements to derive link key from LE: 2965 // - use secure connections 2966 if (setup->sm_use_secure_connections == 0) return false; 2967 // - bonding needs to be enabled: 2968 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; 2969 if (!bonding_enabled) return false; 2970 // - need identity address 2971 bool have_identity_address_info = ((setup->sm_key_distribution_received_set & SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION) != 0); 2972 if (!have_identity_address_info) return false; 2973 // - 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) 2974 // this requirement is motivated by BLURtooth paper. The paper recommends to not overwrite keys at all. 2975 // If SC is authenticated, we consider it safe to overwrite a stored key. 2976 // 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. 2977 uint8_t link_key[16]; 2978 link_key_type_t link_key_type; 2979 bool have_link_key = gap_get_link_key_for_bd_addr(setup->sm_peer_address, link_key, &link_key_type); 2980 bool link_key_authenticated = gap_authenticated_for_link_key_type(link_key_type) != 0; 2981 bool derived_key_authenticated = sm_connection->sm_connection_authenticated != 0; 2982 if (have_link_key && link_key_authenticated && !derived_key_authenticated) { 2983 return false; 2984 } 2985 // get started (all of the above are true) 2986 return true; 2987 #else 2988 return false; 2989 #endif 2990 } 2991 2992 static void sm_handle_encryption_result_enc_csrk(void *arg){ 2993 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 2994 sm_aes128_state = SM_AES128_IDLE; 2995 2996 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 2997 if (connection == NULL) return; 2998 2999 sm_aes128_state = SM_AES128_IDLE; 3000 log_info_key("csrk", setup->sm_local_csrk); 3001 if (setup->sm_key_distribution_send_set){ 3002 connection->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3003 } else { 3004 // no keys to send, just continue 3005 if (IS_RESPONDER(connection->sm_role)){ 3006 // slave -> receive master keys 3007 connection->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3008 } else { 3009 if (sm_ctkd_from_le(connection)){ 3010 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; 3011 connection->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 3012 } else { 3013 sm_master_pairing_success(connection); 3014 } 3015 } 3016 } 3017 sm_trigger_run(); 3018 } 3019 3020 #ifdef ENABLE_LE_PERIPHERAL 3021 static void sm_handle_encryption_result_enc_ph4_ltk(void *arg){ 3022 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3023 sm_aes128_state = SM_AES128_IDLE; 3024 3025 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3026 if (connection == NULL) return; 3027 3028 sm_truncate_key(setup->sm_ltk, connection->sm_actual_encryption_key_size); 3029 log_info_key("ltk", setup->sm_ltk); 3030 connection->sm_engine_state = SM_RESPONDER_PH4_SEND_LTK_REPLY; 3031 sm_trigger_run(); 3032 } 3033 #endif 3034 3035 static void sm_handle_encryption_result_address_resolution(void *arg){ 3036 UNUSED(arg); 3037 sm_aes128_state = SM_AES128_IDLE; 3038 3039 sm_address_resolution_ah_calculation_active = 0; 3040 // compare calulated address against connecting device 3041 uint8_t * hash = &sm_aes128_ciphertext[13]; 3042 if (memcmp(&sm_address_resolution_address[3], hash, 3) == 0){ 3043 log_info("LE Device Lookup: matched resolvable private address"); 3044 sm_address_resolution_handle_event(ADDRESS_RESOLUTION_SUCEEDED); 3045 sm_trigger_run(); 3046 return; 3047 } 3048 // no match, try next 3049 sm_address_resolution_test++; 3050 sm_trigger_run(); 3051 } 3052 3053 static void sm_handle_encryption_result_dkg_irk(void *arg){ 3054 UNUSED(arg); 3055 sm_aes128_state = SM_AES128_IDLE; 3056 3057 log_info_key("irk", sm_persistent_irk); 3058 dkg_state = DKG_CALC_DHK; 3059 sm_trigger_run(); 3060 } 3061 3062 static void sm_handle_encryption_result_dkg_dhk(void *arg){ 3063 UNUSED(arg); 3064 sm_aes128_state = SM_AES128_IDLE; 3065 3066 log_info_key("dhk", sm_persistent_dhk); 3067 dkg_state = DKG_READY; 3068 sm_trigger_run(); 3069 } 3070 3071 static void sm_handle_encryption_result_rau(void *arg){ 3072 UNUSED(arg); 3073 sm_aes128_state = SM_AES128_IDLE; 3074 3075 (void)memcpy(&sm_random_address[3], &sm_aes128_ciphertext[13], 3); 3076 rau_state = RAU_SET_ADDRESS; 3077 sm_trigger_run(); 3078 } 3079 3080 static void sm_handle_random_result_rau(void * arg){ 3081 UNUSED(arg); 3082 // non-resolvable vs. resolvable 3083 switch (gap_random_adress_type){ 3084 case GAP_RANDOM_ADDRESS_RESOLVABLE: 3085 // resolvable: use random as prand and calc address hash 3086 // "The two most significant bits of prand shall be equal to ‘0’ and ‘1" 3087 sm_random_address[0u] &= 0x3fu; 3088 sm_random_address[0u] |= 0x40u; 3089 rau_state = RAU_GET_ENC; 3090 break; 3091 case GAP_RANDOM_ADDRESS_NON_RESOLVABLE: 3092 default: 3093 // "The two most significant bits of the address shall be equal to ‘0’"" 3094 sm_random_address[0u] &= 0x3fu; 3095 rau_state = RAU_SET_ADDRESS; 3096 break; 3097 } 3098 sm_trigger_run(); 3099 } 3100 3101 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3102 static void sm_handle_random_result_sc_next_send_pairing_random(void * arg){ 3103 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3104 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3105 if (connection == NULL) return; 3106 3107 connection->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3108 sm_trigger_run(); 3109 } 3110 3111 static void sm_handle_random_result_sc_next_w2_cmac_for_confirmation(void * arg){ 3112 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3113 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3114 if (connection == NULL) return; 3115 3116 connection->sm_engine_state = SM_SC_W2_CMAC_FOR_CONFIRMATION; 3117 sm_trigger_run(); 3118 } 3119 #endif 3120 3121 static void sm_handle_random_result_ph2_random(void * arg){ 3122 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3123 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3124 if (connection == NULL) return; 3125 3126 connection->sm_engine_state = SM_PH2_C1_GET_ENC_A; 3127 sm_trigger_run(); 3128 } 3129 3130 static void sm_handle_random_result_ph2_tk(void * arg){ 3131 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3132 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3133 if (connection == NULL) return; 3134 3135 sm_reset_tk(); 3136 uint32_t tk; 3137 if (sm_fixed_passkey_in_display_role == 0xffffffff){ 3138 // map random to 0-999999 without speding much cycles on a modulus operation 3139 tk = little_endian_read_32(sm_random_data,0); 3140 tk = tk & 0xfffff; // 1048575 3141 if (tk >= 999999u){ 3142 tk = tk - 999999u; 3143 } 3144 } else { 3145 // override with pre-defined passkey 3146 tk = sm_fixed_passkey_in_display_role; 3147 } 3148 big_endian_store_32(setup->sm_tk, 12, tk); 3149 if (IS_RESPONDER(connection->sm_role)){ 3150 connection->sm_engine_state = SM_RESPONDER_PH1_SEND_PAIRING_RESPONSE; 3151 } else { 3152 if (setup->sm_use_secure_connections){ 3153 connection->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3154 } else { 3155 connection->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3156 sm_trigger_user_response(connection); 3157 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3158 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3159 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); 3160 } 3161 } 3162 } 3163 sm_trigger_run(); 3164 } 3165 3166 static void sm_handle_random_result_ph3_div(void * arg){ 3167 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3168 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3169 if (connection == NULL) return; 3170 3171 // use 16 bit from random value as div 3172 setup->sm_local_div = big_endian_read_16(sm_random_data, 0); 3173 log_info_hex16("div", setup->sm_local_div); 3174 connection->sm_engine_state = SM_PH3_Y_GET_ENC; 3175 sm_trigger_run(); 3176 } 3177 3178 static void sm_handle_random_result_ph3_random(void * arg){ 3179 hci_con_handle_t con_handle = (hci_con_handle_t) (uintptr_t) arg; 3180 sm_connection_t * connection = sm_get_connection_for_handle(con_handle); 3181 if (connection == NULL) return; 3182 3183 reverse_64(sm_random_data, setup->sm_local_rand); 3184 // no db for encryption size hack: encryption size is stored in lowest nibble of setup->sm_local_rand 3185 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xf0u) + (connection->sm_actual_encryption_key_size - 1u); 3186 // no db for authenticated flag hack: store flag in bit 4 of LSB 3187 setup->sm_local_rand[7u] = (setup->sm_local_rand[7u] & 0xefu) + (connection->sm_connection_authenticated << 4u); 3188 btstack_crypto_random_generate(&sm_crypto_random_request, sm_random_data, 2, &sm_handle_random_result_ph3_div, (void *)(uintptr_t) connection->sm_handle); 3189 } 3190 static void sm_validate_er_ir(void){ 3191 // warn about default ER/IR 3192 int warning = 0; 3193 if (sm_ir_is_default()){ 3194 warning = 1; 3195 log_error("Persistent IR not set with sm_set_ir. Use of private addresses will cause pairing issues"); 3196 } 3197 if (sm_er_is_default()){ 3198 warning = 1; 3199 log_error("Persistent ER not set with sm_set_er. Legacy Pairing LTK is not secure"); 3200 } 3201 if (warning) { 3202 log_error("Please configure btstack_tlv to let BTstack setup ER and IR keys"); 3203 } 3204 } 3205 3206 static void sm_handle_random_result_ir(void *arg){ 3207 sm_persistent_keys_random_active = 0; 3208 if (arg){ 3209 // key generated, store in tlv 3210 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3211 log_info("Generated IR key. Store in TLV status: %d", status); 3212 } 3213 log_info_key("IR", sm_persistent_ir); 3214 dkg_state = DKG_CALC_IRK; 3215 3216 if (test_use_fixed_local_irk){ 3217 log_info_key("IRK", sm_persistent_irk); 3218 dkg_state = DKG_CALC_DHK; 3219 } 3220 3221 sm_trigger_run(); 3222 } 3223 3224 static void sm_handle_random_result_er(void *arg){ 3225 sm_persistent_keys_random_active = 0; 3226 if (arg){ 3227 // key generated, store in tlv 3228 int status = sm_tlv_impl->store_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3229 log_info("Generated ER key. Store in TLV status: %d", status); 3230 } 3231 log_info_key("ER", sm_persistent_er); 3232 3233 // try load ir 3234 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','I','R'), sm_persistent_ir, 16u); 3235 if (key_size == 16){ 3236 // ok, let's continue 3237 log_info("IR from TLV"); 3238 sm_handle_random_result_ir( NULL ); 3239 } else { 3240 // invalid, generate new random one 3241 sm_persistent_keys_random_active = 1; 3242 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_ir, 16, &sm_handle_random_result_ir, &sm_persistent_ir); 3243 } 3244 } 3245 3246 static void sm_event_packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size){ 3247 3248 UNUSED(channel); // ok: there is no channel 3249 UNUSED(size); // ok: fixed format HCI events 3250 3251 sm_connection_t * sm_conn; 3252 hci_con_handle_t con_handle; 3253 3254 switch (packet_type) { 3255 3256 case HCI_EVENT_PACKET: 3257 switch (hci_event_packet_get_type(packet)) { 3258 3259 case BTSTACK_EVENT_STATE: 3260 // bt stack activated, get started 3261 if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING){ 3262 log_info("HCI Working!"); 3263 3264 // setup IR/ER with TLV 3265 btstack_tlv_get_instance(&sm_tlv_impl, &sm_tlv_context); 3266 if (sm_tlv_impl){ 3267 int key_size = sm_tlv_impl->get_tag(sm_tlv_context, BTSTACK_TAG32('S','M','E','R'), sm_persistent_er, 16u); 3268 if (key_size == 16){ 3269 // ok, let's continue 3270 log_info("ER from TLV"); 3271 sm_handle_random_result_er( NULL ); 3272 } else { 3273 // invalid, generate random one 3274 sm_persistent_keys_random_active = 1; 3275 btstack_crypto_random_generate(&sm_crypto_random_request, sm_persistent_er, 16, &sm_handle_random_result_er, &sm_persistent_er); 3276 } 3277 } else { 3278 sm_validate_er_ir(); 3279 dkg_state = DKG_CALC_IRK; 3280 3281 if (test_use_fixed_local_irk){ 3282 log_info_key("IRK", sm_persistent_irk); 3283 dkg_state = DKG_CALC_DHK; 3284 } 3285 } 3286 3287 // restart random address updates after power cycle 3288 gap_random_address_set_mode(gap_random_adress_type); 3289 } 3290 break; 3291 3292 case HCI_EVENT_LE_META: 3293 switch (packet[2]) { 3294 case HCI_SUBEVENT_LE_CONNECTION_COMPLETE: 3295 3296 log_info("sm: connected"); 3297 3298 if (packet[3]) return; // connection failed 3299 3300 con_handle = little_endian_read_16(packet, 4); 3301 sm_conn = sm_get_connection_for_handle(con_handle); 3302 if (!sm_conn) break; 3303 3304 sm_conn->sm_handle = con_handle; 3305 sm_conn->sm_role = packet[6]; 3306 sm_conn->sm_peer_addr_type = packet[7]; 3307 reverse_bd_addr(&packet[8], sm_conn->sm_peer_address); 3308 3309 log_info("New sm_conn, role %s", sm_conn->sm_role ? "slave" : "master"); 3310 3311 // reset security properties 3312 sm_conn->sm_connection_encrypted = 0; 3313 sm_conn->sm_connection_authenticated = 0; 3314 sm_conn->sm_connection_authorization_state = AUTHORIZATION_UNKNOWN; 3315 sm_conn->sm_le_db_index = -1; 3316 3317 // prepare CSRK lookup (does not involve setup) 3318 sm_conn->sm_irk_lookup_state = IRK_LOOKUP_W4_READY; 3319 3320 // just connected -> everything else happens in sm_run() 3321 if (IS_RESPONDER(sm_conn->sm_role)){ 3322 // slave - state already could be SM_RESPONDER_SEND_SECURITY_REQUEST instead 3323 if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 3324 if (sm_slave_request_security) { 3325 // request security if requested by app 3326 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 3327 } else { 3328 // otherwise, wait for pairing request 3329 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 3330 } 3331 } 3332 break; 3333 } else { 3334 // master 3335 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3336 } 3337 break; 3338 3339 case HCI_SUBEVENT_LE_LONG_TERM_KEY_REQUEST: 3340 con_handle = little_endian_read_16(packet, 3); 3341 sm_conn = sm_get_connection_for_handle(con_handle); 3342 if (!sm_conn) break; 3343 3344 log_info("LTK Request: state %u", sm_conn->sm_engine_state); 3345 if (sm_conn->sm_engine_state == SM_RESPONDER_PH2_W4_LTK_REQUEST){ 3346 sm_conn->sm_engine_state = SM_PH2_CALC_STK; 3347 break; 3348 } 3349 if (sm_conn->sm_engine_state == SM_SC_W4_LTK_REQUEST_SC){ 3350 // PH2 SEND LTK as we need to exchange keys in PH3 3351 sm_conn->sm_engine_state = SM_RESPONDER_PH2_SEND_LTK_REPLY; 3352 break; 3353 } 3354 3355 // store rand and ediv 3356 reverse_64(&packet[5], sm_conn->sm_local_rand); 3357 sm_conn->sm_local_ediv = little_endian_read_16(packet, 13); 3358 3359 // For Legacy Pairing (<=> EDIV != 0 || RAND != NULL), we need to recalculated our LTK as a 3360 // potentially stored LTK is from the master 3361 if ((sm_conn->sm_local_ediv != 0u) || !sm_is_null_random(sm_conn->sm_local_rand)){ 3362 if (sm_reconstruct_ltk_without_le_device_db_entry){ 3363 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3364 break; 3365 } 3366 // additionally check if remote is in LE Device DB if requested 3367 switch(sm_conn->sm_irk_lookup_state){ 3368 case IRK_LOOKUP_FAILED: 3369 log_info("LTK Request: device not in device db"); 3370 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3371 break; 3372 case IRK_LOOKUP_SUCCEEDED: 3373 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_REQUEST; 3374 break; 3375 default: 3376 // wait for irk look doen 3377 sm_conn->sm_engine_state = SM_RESPONDER_PH0_RECEIVED_LTK_W4_IRK; 3378 break; 3379 } 3380 break; 3381 } 3382 3383 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3384 sm_conn->sm_engine_state = SM_SC_RECEIVED_LTK_REQUEST; 3385 #else 3386 log_info("LTK Request: ediv & random are empty, but LE Secure Connections not supported"); 3387 sm_conn->sm_engine_state = SM_RESPONDER_PH0_SEND_LTK_REQUESTED_NEGATIVE_REPLY; 3388 #endif 3389 break; 3390 3391 default: 3392 break; 3393 } 3394 break; 3395 3396 case HCI_EVENT_ENCRYPTION_CHANGE: 3397 con_handle = little_endian_read_16(packet, 3); 3398 sm_conn = sm_get_connection_for_handle(con_handle); 3399 if (!sm_conn) break; 3400 3401 sm_conn->sm_connection_encrypted = packet[5]; 3402 log_info("Encryption state change: %u, key size %u", sm_conn->sm_connection_encrypted, 3403 sm_conn->sm_actual_encryption_key_size); 3404 log_info("event handler, state %u", sm_conn->sm_engine_state); 3405 3406 // encryption change event concludes re-encryption for bonded devices (even if it fails) 3407 if (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED){ 3408 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3409 // notify client, if pairing was requested before 3410 if (sm_conn->sm_pairing_requested){ 3411 sm_conn->sm_pairing_requested = 0; 3412 if (sm_conn->sm_connection_encrypted){ 3413 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 3414 } else { 3415 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, 0); 3416 } 3417 } 3418 sm_done_for_handle(sm_conn->sm_handle); 3419 break; 3420 } 3421 3422 if (!sm_conn->sm_connection_encrypted) break; 3423 sm_conn->sm_connection_sc = setup->sm_use_secure_connections; 3424 3425 // continue pairing 3426 switch (sm_conn->sm_engine_state){ 3427 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3428 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3429 sm_done_for_handle(sm_conn->sm_handle); 3430 break; 3431 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3432 if (IS_RESPONDER(sm_conn->sm_role)){ 3433 // slave 3434 if (setup->sm_use_secure_connections){ 3435 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 3436 } else { 3437 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); 3438 } 3439 } else { 3440 // master 3441 if (sm_key_distribution_all_received(sm_conn)){ 3442 // skip receiving keys as there are none 3443 sm_key_distribution_handle_all_received(sm_conn); 3444 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); 3445 } else { 3446 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3447 } 3448 } 3449 break; 3450 default: 3451 break; 3452 } 3453 break; 3454 3455 case HCI_EVENT_ENCRYPTION_KEY_REFRESH_COMPLETE: 3456 con_handle = little_endian_read_16(packet, 3); 3457 sm_conn = sm_get_connection_for_handle(con_handle); 3458 if (!sm_conn) break; 3459 3460 log_info("Encryption key refresh complete, key size %u", sm_conn->sm_actual_encryption_key_size); 3461 log_info("event handler, state %u", sm_conn->sm_engine_state); 3462 // continue if part of initial pairing 3463 switch (sm_conn->sm_engine_state){ 3464 case SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED: 3465 sm_conn->sm_engine_state = SM_INITIATOR_CONNECTED; 3466 sm_done_for_handle(sm_conn->sm_handle); 3467 break; 3468 case SM_PH2_W4_CONNECTION_ENCRYPTED: 3469 if (IS_RESPONDER(sm_conn->sm_role)){ 3470 // slave 3471 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); 3472 } else { 3473 // master 3474 sm_conn->sm_engine_state = SM_PH3_RECEIVE_KEYS; 3475 } 3476 break; 3477 default: 3478 break; 3479 } 3480 break; 3481 3482 3483 case HCI_EVENT_DISCONNECTION_COMPLETE: 3484 con_handle = little_endian_read_16(packet, 3); 3485 sm_done_for_handle(con_handle); 3486 sm_conn = sm_get_connection_for_handle(con_handle); 3487 if (!sm_conn) break; 3488 3489 // delete stored bonding on disconnect with authentication failure in ph0 3490 if ((sm_conn->sm_role == 0u) 3491 && (sm_conn->sm_engine_state == SM_INITIATOR_PH0_W4_CONNECTION_ENCRYPTED) 3492 && (packet[2] == ERROR_CODE_AUTHENTICATION_FAILURE)){ 3493 le_device_db_remove(sm_conn->sm_le_db_index); 3494 } 3495 3496 // pairing failed, if it was ongoing 3497 switch (sm_conn->sm_engine_state){ 3498 case SM_GENERAL_IDLE: 3499 case SM_INITIATOR_CONNECTED: 3500 case SM_RESPONDER_IDLE: 3501 break; 3502 default: 3503 sm_notify_client_status_reason(sm_conn, ERROR_CODE_REMOTE_USER_TERMINATED_CONNECTION, 0); 3504 break; 3505 } 3506 3507 sm_conn->sm_engine_state = SM_GENERAL_IDLE; 3508 sm_conn->sm_handle = 0; 3509 break; 3510 3511 case HCI_EVENT_COMMAND_COMPLETE: 3512 if (HCI_EVENT_IS_COMMAND_COMPLETE(packet, hci_read_bd_addr)){ 3513 // set local addr for le device db 3514 bd_addr_t addr; 3515 reverse_bd_addr(&packet[OFFSET_OF_DATA_IN_COMMAND_COMPLETE + 1], addr); 3516 le_device_db_set_local_bd_addr(addr); 3517 } 3518 break; 3519 default: 3520 break; 3521 } 3522 break; 3523 default: 3524 break; 3525 } 3526 3527 sm_run(); 3528 } 3529 3530 static inline int sm_calc_actual_encryption_key_size(int other){ 3531 if (other < sm_min_encryption_key_size) return 0; 3532 if (other < sm_max_encryption_key_size) return other; 3533 return sm_max_encryption_key_size; 3534 } 3535 3536 3537 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3538 static int sm_just_works_or_numeric_comparison(stk_generation_method_t method){ 3539 switch (method){ 3540 case JUST_WORKS: 3541 case NUMERIC_COMPARISON: 3542 return 1; 3543 default: 3544 return 0; 3545 } 3546 } 3547 // responder 3548 3549 static int sm_passkey_used(stk_generation_method_t method){ 3550 switch (method){ 3551 case PK_RESP_INPUT: 3552 return 1; 3553 default: 3554 return 0; 3555 } 3556 } 3557 3558 static int sm_passkey_entry(stk_generation_method_t method){ 3559 switch (method){ 3560 case PK_RESP_INPUT: 3561 case PK_INIT_INPUT: 3562 case PK_BOTH_INPUT: 3563 return 1; 3564 default: 3565 return 0; 3566 } 3567 } 3568 3569 #endif 3570 3571 /** 3572 * @return ok 3573 */ 3574 static int sm_validate_stk_generation_method(void){ 3575 // check if STK generation method is acceptable by client 3576 switch (setup->sm_stk_generation_method){ 3577 case JUST_WORKS: 3578 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_JUST_WORKS) != 0u; 3579 case PK_RESP_INPUT: 3580 case PK_INIT_INPUT: 3581 case PK_BOTH_INPUT: 3582 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_PASSKEY) != 0u; 3583 case OOB: 3584 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_OOB) != 0u; 3585 case NUMERIC_COMPARISON: 3586 return (sm_accepted_stk_generation_methods & SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON) != 0u; 3587 default: 3588 return 0; 3589 } 3590 } 3591 3592 static void sm_pdu_handler(uint8_t packet_type, hci_con_handle_t con_handle, uint8_t *packet, uint16_t size){ 3593 3594 // size of complete sm_pdu used to validate input 3595 static const uint8_t sm_pdu_size[] = { 3596 0, // 0x00 invalid opcode 3597 7, // 0x01 pairing request 3598 7, // 0x02 pairing response 3599 17, // 0x03 pairing confirm 3600 17, // 0x04 pairing random 3601 2, // 0x05 pairing failed 3602 17, // 0x06 encryption information 3603 11, // 0x07 master identification 3604 17, // 0x08 identification information 3605 8, // 0x09 identify address information 3606 17, // 0x0a signing information 3607 2, // 0x0b security request 3608 65, // 0x0c pairing public key 3609 17, // 0x0d pairing dhk check 3610 2, // 0x0e keypress notification 3611 }; 3612 3613 if ((packet_type == HCI_EVENT_PACKET) && (packet[0] == L2CAP_EVENT_CAN_SEND_NOW)){ 3614 sm_run(); 3615 } 3616 3617 if (packet_type != SM_DATA_PACKET) return; 3618 if (size == 0u) return; 3619 3620 uint8_t sm_pdu_code = packet[0]; 3621 3622 // validate pdu size 3623 if (sm_pdu_code >= sizeof(sm_pdu_size)) return; 3624 if (sm_pdu_size[sm_pdu_code] != size) return; 3625 3626 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 3627 if (!sm_conn) return; 3628 3629 if (sm_pdu_code == SM_CODE_PAIRING_FAILED){ 3630 sm_notify_client_status_reason(sm_conn, ERROR_CODE_AUTHENTICATION_FAILURE, packet[1]); 3631 sm_done_for_handle(con_handle); 3632 sm_conn->sm_engine_state = sm_conn->sm_role ? SM_RESPONDER_IDLE : SM_INITIATOR_CONNECTED; 3633 return; 3634 } 3635 3636 log_debug("sm_pdu_handler: state %u, pdu 0x%02x", sm_conn->sm_engine_state, sm_pdu_code); 3637 3638 int err; 3639 UNUSED(err); 3640 3641 if (sm_pdu_code == SM_CODE_KEYPRESS_NOTIFICATION){ 3642 uint8_t buffer[5]; 3643 buffer[0] = SM_EVENT_KEYPRESS_NOTIFICATION; 3644 buffer[1] = 3; 3645 little_endian_store_16(buffer, 2, con_handle); 3646 buffer[4] = packet[1]; 3647 sm_dispatch_event(HCI_EVENT_PACKET, 0, buffer, sizeof(buffer)); 3648 return; 3649 } 3650 3651 switch (sm_conn->sm_engine_state){ 3652 3653 // a sm timeout requries a new physical connection 3654 case SM_GENERAL_TIMEOUT: 3655 return; 3656 3657 #ifdef ENABLE_LE_CENTRAL 3658 3659 // Initiator 3660 case SM_INITIATOR_CONNECTED: 3661 if ((sm_pdu_code != SM_CODE_SECURITY_REQUEST) || (sm_conn->sm_role)){ 3662 sm_pdu_received_in_wrong_state(sm_conn); 3663 break; 3664 } 3665 3666 // IRK complete? 3667 int have_ltk; 3668 uint8_t ltk[16]; 3669 switch (sm_conn->sm_irk_lookup_state){ 3670 case IRK_LOOKUP_FAILED: 3671 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3672 break; 3673 case IRK_LOOKUP_SUCCEEDED: 3674 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 3675 have_ltk = !sm_is_null_key(ltk); 3676 log_info("central: security request - have_ltk %u", have_ltk); 3677 if (have_ltk){ 3678 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 3679 } else { 3680 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 3681 } 3682 break; 3683 default: 3684 break; 3685 } 3686 3687 // otherwise, store security request 3688 sm_conn->sm_security_request_received = 1; 3689 break; 3690 3691 case SM_INITIATOR_PH1_W4_PAIRING_RESPONSE: 3692 // Core 5, Vol 3, Part H, 2.4.6: 3693 // "The master shall ignore the slave’s Security Request if the master has sent a Pairing Request 3694 // without receiving a Pairing Response from the slave or if the master has initiated encryption mode setup." 3695 if (sm_pdu_code == SM_CODE_SECURITY_REQUEST){ 3696 log_info("Ignoring Security Request"); 3697 break; 3698 } 3699 3700 // all other pdus are incorrect 3701 if (sm_pdu_code != SM_CODE_PAIRING_RESPONSE){ 3702 sm_pdu_received_in_wrong_state(sm_conn); 3703 break; 3704 } 3705 3706 // store pairing request 3707 (void)memcpy(&setup->sm_s_pres, packet, 3708 sizeof(sm_pairing_packet_t)); 3709 err = sm_stk_generation_init(sm_conn); 3710 3711 #ifdef ENABLE_TESTING_SUPPORT 3712 if (0 < test_pairing_failure && test_pairing_failure < SM_REASON_DHKEY_CHECK_FAILED){ 3713 log_info("testing_support: abort with pairing failure %u", test_pairing_failure); 3714 err = test_pairing_failure; 3715 } 3716 #endif 3717 3718 if (err){ 3719 setup->sm_pairing_failed_reason = err; 3720 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3721 break; 3722 } 3723 3724 // generate random number first, if we need to show passkey 3725 if (setup->sm_stk_generation_method == PK_RESP_INPUT){ 3726 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); 3727 break; 3728 } 3729 3730 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3731 if (setup->sm_use_secure_connections){ 3732 // SC Numeric Comparison will trigger user response after public keys & nonces have been exchanged 3733 if (setup->sm_stk_generation_method == JUST_WORKS){ 3734 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3735 sm_trigger_user_response(sm_conn); 3736 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3737 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3738 } 3739 } else { 3740 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3741 } 3742 break; 3743 } 3744 #endif 3745 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 3746 sm_trigger_user_response(sm_conn); 3747 // response_idle == nothing <--> sm_trigger_user_response() did not require response 3748 if (setup->sm_user_response == SM_USER_RESPONSE_IDLE){ 3749 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); 3750 } 3751 break; 3752 3753 case SM_INITIATOR_PH2_W4_PAIRING_CONFIRM: 3754 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3755 sm_pdu_received_in_wrong_state(sm_conn); 3756 break; 3757 } 3758 3759 // store s_confirm 3760 reverse_128(&packet[1], setup->sm_peer_confirm); 3761 3762 #ifdef ENABLE_TESTING_SUPPORT 3763 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3764 log_info("testing_support: reset confirm value"); 3765 memset(setup->sm_peer_confirm, 0, 16); 3766 } 3767 #endif 3768 sm_conn->sm_engine_state = SM_PH2_SEND_PAIRING_RANDOM; 3769 break; 3770 3771 case SM_INITIATOR_PH2_W4_PAIRING_RANDOM: 3772 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3773 sm_pdu_received_in_wrong_state(sm_conn); 3774 break;; 3775 } 3776 3777 // received random value 3778 reverse_128(&packet[1], setup->sm_peer_random); 3779 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 3780 break; 3781 #endif 3782 3783 #ifdef ENABLE_LE_PERIPHERAL 3784 // Responder 3785 case SM_RESPONDER_IDLE: 3786 case SM_RESPONDER_SEND_SECURITY_REQUEST: 3787 case SM_RESPONDER_PH1_W4_PAIRING_REQUEST: 3788 if (sm_pdu_code != SM_CODE_PAIRING_REQUEST){ 3789 sm_pdu_received_in_wrong_state(sm_conn); 3790 break;; 3791 } 3792 3793 // store pairing request 3794 (void)memcpy(&sm_conn->sm_m_preq, packet, 3795 sizeof(sm_pairing_packet_t)); 3796 sm_conn->sm_engine_state = SM_RESPONDER_PH1_PAIRING_REQUEST_RECEIVED; 3797 break; 3798 #endif 3799 3800 #ifdef ENABLE_LE_SECURE_CONNECTIONS 3801 case SM_SC_W4_PUBLIC_KEY_COMMAND: 3802 if (sm_pdu_code != SM_CODE_PAIRING_PUBLIC_KEY){ 3803 sm_pdu_received_in_wrong_state(sm_conn); 3804 break; 3805 } 3806 3807 // store public key for DH Key calculation 3808 reverse_256(&packet[01], &setup->sm_peer_q[0]); 3809 reverse_256(&packet[33], &setup->sm_peer_q[32]); 3810 3811 // validate public key 3812 err = btstack_crypto_ecc_p256_validate_public_key(setup->sm_peer_q); 3813 if (err){ 3814 log_error("sm: peer public key invalid %x", err); 3815 sm_pairing_error(sm_conn, SM_REASON_DHKEY_CHECK_FAILED); 3816 break; 3817 } 3818 3819 // start calculating dhkey 3820 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); 3821 3822 3823 log_info("public key received, generation method %u", setup->sm_stk_generation_method); 3824 if (IS_RESPONDER(sm_conn->sm_role)){ 3825 // responder 3826 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 3827 } else { 3828 // initiator 3829 // stk generation method 3830 // passkey entry: notify app to show passkey or to request passkey 3831 switch (setup->sm_stk_generation_method){ 3832 case JUST_WORKS: 3833 case NUMERIC_COMPARISON: 3834 sm_conn->sm_engine_state = SM_SC_W4_CONFIRMATION; 3835 break; 3836 case PK_RESP_INPUT: 3837 sm_sc_start_calculating_local_confirm(sm_conn); 3838 break; 3839 case PK_INIT_INPUT: 3840 case PK_BOTH_INPUT: 3841 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3842 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3843 break; 3844 } 3845 sm_sc_start_calculating_local_confirm(sm_conn); 3846 break; 3847 case OOB: 3848 // generate Nx 3849 log_info("Generate Na"); 3850 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); 3851 break; 3852 } 3853 } 3854 break; 3855 3856 case SM_SC_W4_CONFIRMATION: 3857 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3858 sm_pdu_received_in_wrong_state(sm_conn); 3859 break; 3860 } 3861 // received confirm value 3862 reverse_128(&packet[1], setup->sm_peer_confirm); 3863 3864 #ifdef ENABLE_TESTING_SUPPORT 3865 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3866 log_info("testing_support: reset confirm value"); 3867 memset(setup->sm_peer_confirm, 0, 16); 3868 } 3869 #endif 3870 if (IS_RESPONDER(sm_conn->sm_role)){ 3871 // responder 3872 if (sm_passkey_used(setup->sm_stk_generation_method)){ 3873 if (setup->sm_user_response != SM_USER_RESPONSE_PASSKEY){ 3874 // still waiting for passkey 3875 sm_conn->sm_engine_state = SM_SC_W4_USER_RESPONSE; 3876 break; 3877 } 3878 } 3879 sm_sc_start_calculating_local_confirm(sm_conn); 3880 } else { 3881 // initiator 3882 if (sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)){ 3883 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); 3884 } else { 3885 sm_conn->sm_engine_state = SM_SC_SEND_PAIRING_RANDOM; 3886 } 3887 } 3888 break; 3889 3890 case SM_SC_W4_PAIRING_RANDOM: 3891 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 3892 sm_pdu_received_in_wrong_state(sm_conn); 3893 break; 3894 } 3895 3896 // received random value 3897 reverse_128(&packet[1], setup->sm_peer_nonce); 3898 3899 // validate confirm value if Cb = f4(Pkb, Pka, Nb, z) 3900 // only check for JUST WORK/NC in initiator role OR passkey entry 3901 log_info("SM_SC_W4_PAIRING_RANDOM, responder: %u, just works: %u, passkey used %u, passkey entry %u", 3902 IS_RESPONDER(sm_conn->sm_role), sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method), 3903 sm_passkey_used(setup->sm_stk_generation_method), sm_passkey_entry(setup->sm_stk_generation_method)); 3904 if ( (!IS_RESPONDER(sm_conn->sm_role) && sm_just_works_or_numeric_comparison(setup->sm_stk_generation_method)) 3905 || (sm_passkey_entry(setup->sm_stk_generation_method)) ) { 3906 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3907 break; 3908 } 3909 3910 // OOB 3911 if (setup->sm_stk_generation_method == OOB){ 3912 3913 // setup local random, set to zero if remote did not receive our data 3914 log_info("Received nonce, setup local random ra/rb for dhkey check"); 3915 if (IS_RESPONDER(sm_conn->sm_role)){ 3916 if (sm_pairing_packet_get_oob_data_flag(setup->sm_m_preq) == 0u){ 3917 log_info("Reset rb as A does not have OOB data"); 3918 memset(setup->sm_rb, 0, 16); 3919 } else { 3920 (void)memcpy(setup->sm_rb, sm_sc_oob_random, 16); 3921 log_info("Use stored rb"); 3922 log_info_hexdump(setup->sm_rb, 16); 3923 } 3924 } else { 3925 if (sm_pairing_packet_get_oob_data_flag(setup->sm_s_pres) == 0u){ 3926 log_info("Reset ra as B does not have OOB data"); 3927 memset(setup->sm_ra, 0, 16); 3928 } else { 3929 (void)memcpy(setup->sm_ra, sm_sc_oob_random, 16); 3930 log_info("Use stored ra"); 3931 log_info_hexdump(setup->sm_ra, 16); 3932 } 3933 } 3934 3935 // validate confirm value if Cb = f4(PKb, Pkb, rb, 0) for OOB if data received 3936 if (setup->sm_have_oob_data){ 3937 sm_conn->sm_engine_state = SM_SC_W2_CMAC_FOR_CHECK_CONFIRMATION; 3938 break; 3939 } 3940 } 3941 3942 // TODO: we only get here for Responder role with JW/NC 3943 sm_sc_state_after_receiving_random(sm_conn); 3944 break; 3945 3946 case SM_SC_W2_CALCULATE_G2: 3947 case SM_SC_W4_CALCULATE_G2: 3948 case SM_SC_W4_CALCULATE_DHKEY: 3949 case SM_SC_W2_CALCULATE_F5_SALT: 3950 case SM_SC_W4_CALCULATE_F5_SALT: 3951 case SM_SC_W2_CALCULATE_F5_MACKEY: 3952 case SM_SC_W4_CALCULATE_F5_MACKEY: 3953 case SM_SC_W2_CALCULATE_F5_LTK: 3954 case SM_SC_W4_CALCULATE_F5_LTK: 3955 case SM_SC_W2_CALCULATE_F6_FOR_DHKEY_CHECK: 3956 case SM_SC_W4_DHKEY_CHECK_COMMAND: 3957 case SM_SC_W4_CALCULATE_F6_FOR_DHKEY_CHECK: 3958 case SM_SC_W4_USER_RESPONSE: 3959 if (sm_pdu_code != SM_CODE_PAIRING_DHKEY_CHECK){ 3960 sm_pdu_received_in_wrong_state(sm_conn); 3961 break; 3962 } 3963 // store DHKey Check 3964 setup->sm_state_vars |= SM_STATE_VAR_DHKEY_COMMAND_RECEIVED; 3965 reverse_128(&packet[01], setup->sm_peer_dhkey_check); 3966 3967 // have we been only waiting for dhkey check command? 3968 if (sm_conn->sm_engine_state == SM_SC_W4_DHKEY_CHECK_COMMAND){ 3969 sm_conn->sm_engine_state = SM_SC_W2_CALCULATE_F6_TO_VERIFY_DHKEY_CHECK; 3970 } 3971 break; 3972 #endif 3973 3974 #ifdef ENABLE_LE_PERIPHERAL 3975 case SM_RESPONDER_PH1_W4_PAIRING_CONFIRM: 3976 if (sm_pdu_code != SM_CODE_PAIRING_CONFIRM){ 3977 sm_pdu_received_in_wrong_state(sm_conn); 3978 break; 3979 } 3980 3981 // received confirm value 3982 reverse_128(&packet[1], setup->sm_peer_confirm); 3983 3984 #ifdef ENABLE_TESTING_SUPPORT 3985 if (test_pairing_failure == SM_REASON_CONFIRM_VALUE_FAILED){ 3986 log_info("testing_support: reset confirm value"); 3987 memset(setup->sm_peer_confirm, 0, 16); 3988 } 3989 #endif 3990 // notify client to hide shown passkey 3991 if (setup->sm_stk_generation_method == PK_INIT_INPUT){ 3992 sm_notify_client_base(SM_EVENT_PASSKEY_DISPLAY_CANCEL, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address); 3993 } 3994 3995 // handle user cancel pairing? 3996 if (setup->sm_user_response == SM_USER_RESPONSE_DECLINE){ 3997 setup->sm_pairing_failed_reason = SM_REASON_PASSKEY_ENTRY_FAILED; 3998 sm_conn->sm_engine_state = SM_GENERAL_SEND_PAIRING_FAILED; 3999 break; 4000 } 4001 4002 // wait for user action? 4003 if (setup->sm_user_response == SM_USER_RESPONSE_PENDING){ 4004 sm_conn->sm_engine_state = SM_PH1_W4_USER_RESPONSE; 4005 break; 4006 } 4007 4008 // calculate and send local_confirm 4009 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); 4010 break; 4011 4012 case SM_RESPONDER_PH2_W4_PAIRING_RANDOM: 4013 if (sm_pdu_code != SM_CODE_PAIRING_RANDOM){ 4014 sm_pdu_received_in_wrong_state(sm_conn); 4015 break;; 4016 } 4017 4018 // received random value 4019 reverse_128(&packet[1], setup->sm_peer_random); 4020 sm_conn->sm_engine_state = SM_PH2_C1_GET_ENC_C; 4021 break; 4022 #endif 4023 4024 case SM_PH3_RECEIVE_KEYS: 4025 switch(sm_pdu_code){ 4026 case SM_CODE_ENCRYPTION_INFORMATION: 4027 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_ENCRYPTION_INFORMATION; 4028 reverse_128(&packet[1], setup->sm_peer_ltk); 4029 break; 4030 4031 case SM_CODE_MASTER_IDENTIFICATION: 4032 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_MASTER_IDENTIFICATION; 4033 setup->sm_peer_ediv = little_endian_read_16(packet, 1); 4034 reverse_64(&packet[3], setup->sm_peer_rand); 4035 break; 4036 4037 case SM_CODE_IDENTITY_INFORMATION: 4038 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_INFORMATION; 4039 reverse_128(&packet[1], setup->sm_peer_irk); 4040 break; 4041 4042 case SM_CODE_IDENTITY_ADDRESS_INFORMATION: 4043 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_IDENTITY_ADDRESS_INFORMATION; 4044 setup->sm_peer_addr_type = packet[1]; 4045 reverse_bd_addr(&packet[2], setup->sm_peer_address); 4046 break; 4047 4048 case SM_CODE_SIGNING_INFORMATION: 4049 setup->sm_key_distribution_received_set |= SM_KEYDIST_FLAG_SIGNING_IDENTIFICATION; 4050 reverse_128(&packet[1], setup->sm_peer_csrk); 4051 break; 4052 default: 4053 // Unexpected PDU 4054 log_info("Unexpected PDU %u in SM_PH3_RECEIVE_KEYS", packet[0]); 4055 break; 4056 } 4057 // done with key distribution? 4058 if (sm_key_distribution_all_received(sm_conn)){ 4059 4060 sm_key_distribution_handle_all_received(sm_conn); 4061 4062 if (IS_RESPONDER(sm_conn->sm_role)){ 4063 if (sm_ctkd_from_le(sm_conn)){ 4064 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; 4065 sm_conn->sm_engine_state = use_h7 ? SM_SC_W2_CALCULATE_ILK_USING_H7 : SM_SC_W2_CALCULATE_ILK_USING_H6; 4066 } else { 4067 sm_conn->sm_engine_state = SM_RESPONDER_IDLE; 4068 sm_notify_client_status_reason(sm_conn, ERROR_CODE_SUCCESS, 0); 4069 sm_done_for_handle(sm_conn->sm_handle); 4070 } 4071 } else { 4072 if (setup->sm_use_secure_connections){ 4073 sm_conn->sm_engine_state = SM_PH3_DISTRIBUTE_KEYS; 4074 } else { 4075 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); 4076 } 4077 } 4078 } 4079 break; 4080 default: 4081 // Unexpected PDU 4082 log_info("Unexpected PDU %u in state %u", packet[0], sm_conn->sm_engine_state); 4083 break; 4084 } 4085 4086 // try to send next pdu 4087 sm_trigger_run(); 4088 } 4089 4090 // Security Manager Client API 4091 void sm_register_oob_data_callback( int (*get_oob_data_callback)(uint8_t address_type, bd_addr_t addr, uint8_t * oob_data)){ 4092 sm_get_oob_data = get_oob_data_callback; 4093 } 4094 4095 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)){ 4096 sm_get_sc_oob_data = get_sc_oob_data_callback; 4097 } 4098 4099 void sm_add_event_handler(btstack_packet_callback_registration_t * callback_handler){ 4100 btstack_linked_list_add_tail(&sm_event_handlers, (btstack_linked_item_t*) callback_handler); 4101 } 4102 4103 void sm_set_accepted_stk_generation_methods(uint8_t accepted_stk_generation_methods){ 4104 sm_accepted_stk_generation_methods = accepted_stk_generation_methods; 4105 } 4106 4107 void sm_set_encryption_key_size_range(uint8_t min_size, uint8_t max_size){ 4108 sm_min_encryption_key_size = min_size; 4109 sm_max_encryption_key_size = max_size; 4110 } 4111 4112 void sm_set_authentication_requirements(uint8_t auth_req){ 4113 #ifndef ENABLE_LE_SECURE_CONNECTIONS 4114 if (auth_req & SM_AUTHREQ_SECURE_CONNECTION){ 4115 log_error("ENABLE_LE_SECURE_CONNECTIONS not defined, but requested by app. Dropping SC flag"); 4116 auth_req &= ~SM_AUTHREQ_SECURE_CONNECTION; 4117 } 4118 #endif 4119 sm_auth_req = auth_req; 4120 } 4121 4122 void sm_set_io_capabilities(io_capability_t io_capability){ 4123 sm_io_capabilities = io_capability; 4124 } 4125 4126 #ifdef ENABLE_LE_PERIPHERAL 4127 void sm_set_request_security(int enable){ 4128 sm_slave_request_security = enable; 4129 } 4130 #endif 4131 4132 void sm_set_er(sm_key_t er){ 4133 (void)memcpy(sm_persistent_er, er, 16); 4134 } 4135 4136 void sm_set_ir(sm_key_t ir){ 4137 (void)memcpy(sm_persistent_ir, ir, 16); 4138 } 4139 4140 // Testing support only 4141 void sm_test_set_irk(sm_key_t irk){ 4142 (void)memcpy(sm_persistent_irk, irk, 16); 4143 dkg_state = DKG_CALC_DHK; 4144 test_use_fixed_local_irk = true; 4145 } 4146 4147 void sm_test_use_fixed_local_csrk(void){ 4148 test_use_fixed_local_csrk = true; 4149 } 4150 4151 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4152 static void sm_ec_generated(void * arg){ 4153 UNUSED(arg); 4154 ec_key_generation_state = EC_KEY_GENERATION_DONE; 4155 // trigger pairing if pending for ec key 4156 sm_trigger_run(); 4157 } 4158 static void sm_ec_generate_new_key(void){ 4159 log_info("sm: generate new ec key"); 4160 ec_key_generation_state = EC_KEY_GENERATION_ACTIVE; 4161 btstack_crypto_ecc_p256_generate_key(&sm_crypto_ecc_p256_request, ec_q, &sm_ec_generated, NULL); 4162 } 4163 #endif 4164 4165 #ifdef ENABLE_TESTING_SUPPORT 4166 void sm_test_set_pairing_failure(int reason){ 4167 test_pairing_failure = reason; 4168 } 4169 #endif 4170 4171 void sm_init(void){ 4172 // set default ER and IR values (should be unique - set by app or sm later using TLV) 4173 sm_er_ir_set_default(); 4174 4175 // defaults 4176 sm_accepted_stk_generation_methods = SM_STK_GENERATION_METHOD_JUST_WORKS 4177 | SM_STK_GENERATION_METHOD_OOB 4178 | SM_STK_GENERATION_METHOD_PASSKEY 4179 | SM_STK_GENERATION_METHOD_NUMERIC_COMPARISON; 4180 4181 sm_max_encryption_key_size = 16; 4182 sm_min_encryption_key_size = 7; 4183 4184 sm_fixed_passkey_in_display_role = 0xffffffff; 4185 sm_reconstruct_ltk_without_le_device_db_entry = 1; 4186 4187 #ifdef USE_CMAC_ENGINE 4188 sm_cmac_active = 0; 4189 #endif 4190 dkg_state = DKG_W4_WORKING; 4191 rau_state = RAU_IDLE; 4192 sm_aes128_state = SM_AES128_IDLE; 4193 sm_address_resolution_test = -1; // no private address to resolve yet 4194 sm_address_resolution_ah_calculation_active = 0; 4195 sm_address_resolution_mode = ADDRESS_RESOLUTION_IDLE; 4196 sm_address_resolution_general_queue = NULL; 4197 4198 gap_random_adress_update_period = 15 * 60 * 1000L; 4199 sm_active_connection_handle = HCI_CON_HANDLE_INVALID; 4200 4201 test_use_fixed_local_csrk = false; 4202 4203 btstack_run_loop_set_timer_handler(&sm_run_timer, &sm_run_timer_handler); 4204 4205 // register for HCI Events from HCI 4206 hci_event_callback_registration.callback = &sm_event_packet_handler; 4207 hci_add_event_handler(&hci_event_callback_registration); 4208 4209 // 4210 btstack_crypto_init(); 4211 4212 // init le_device_db 4213 le_device_db_init(); 4214 4215 // and L2CAP PDUs + L2CAP_EVENT_CAN_SEND_NOW 4216 l2cap_register_fixed_channel(sm_pdu_handler, L2CAP_CID_SECURITY_MANAGER_PROTOCOL); 4217 4218 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4219 sm_ec_generate_new_key(); 4220 #endif 4221 } 4222 4223 void sm_use_fixed_passkey_in_display_role(uint32_t passkey){ 4224 sm_fixed_passkey_in_display_role = passkey; 4225 } 4226 4227 void sm_allow_ltk_reconstruction_without_le_device_db_entry(int allow){ 4228 sm_reconstruct_ltk_without_le_device_db_entry = allow; 4229 } 4230 4231 static sm_connection_t * sm_get_connection_for_handle(hci_con_handle_t con_handle){ 4232 hci_connection_t * hci_con = hci_connection_for_handle(con_handle); 4233 if (!hci_con) return NULL; 4234 return &hci_con->sm_connection; 4235 } 4236 4237 static void sm_send_security_request_for_connection(sm_connection_t * sm_conn){ 4238 switch (sm_conn->sm_engine_state){ 4239 case SM_GENERAL_IDLE: 4240 case SM_RESPONDER_IDLE: 4241 sm_conn->sm_engine_state = SM_RESPONDER_SEND_SECURITY_REQUEST; 4242 sm_trigger_run(); 4243 break; 4244 default: 4245 break; 4246 } 4247 } 4248 4249 /** 4250 * @brief Trigger Security Request 4251 */ 4252 void sm_send_security_request(hci_con_handle_t con_handle){ 4253 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4254 if (!sm_conn) return; 4255 sm_send_security_request_for_connection(sm_conn); 4256 } 4257 4258 // request pairing 4259 void sm_request_pairing(hci_con_handle_t con_handle){ 4260 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4261 if (!sm_conn) return; // wrong connection 4262 4263 log_info("sm_request_pairing in role %u, state %u", sm_conn->sm_role, sm_conn->sm_engine_state); 4264 if (IS_RESPONDER(sm_conn->sm_role)){ 4265 sm_send_security_request_for_connection(sm_conn); 4266 } else { 4267 // used as a trigger to start central/master/initiator security procedures 4268 if (sm_conn->sm_engine_state == SM_INITIATOR_CONNECTED){ 4269 uint8_t ltk[16]; 4270 bool have_ltk; 4271 switch (sm_conn->sm_irk_lookup_state){ 4272 case IRK_LOOKUP_SUCCEEDED: 4273 #ifndef ENABLE_LE_CENTRAL_AUTO_ENCRYPTION 4274 le_device_db_encryption_get(sm_conn->sm_le_db_index, NULL, NULL, ltk, NULL, NULL, NULL, NULL); 4275 have_ltk = !sm_is_null_key(ltk); 4276 log_info("have ltk %u", have_ltk); 4277 if (have_ltk){ 4278 sm_conn->sm_pairing_requested = 1; 4279 sm_conn->sm_engine_state = SM_INITIATOR_PH0_HAS_LTK; 4280 break; 4281 } 4282 #endif 4283 /* fall through */ 4284 4285 case IRK_LOOKUP_FAILED: 4286 sm_conn->sm_engine_state = SM_INITIATOR_PH1_W2_SEND_PAIRING_REQUEST; 4287 break; 4288 default: 4289 log_info("irk lookup pending"); 4290 sm_conn->sm_pairing_requested = 1; 4291 break; 4292 } 4293 } else if (sm_conn->sm_engine_state == SM_GENERAL_IDLE){ 4294 sm_conn->sm_pairing_requested = 1; 4295 } 4296 } 4297 sm_trigger_run(); 4298 } 4299 4300 // called by client app on authorization request 4301 void sm_authorization_decline(hci_con_handle_t con_handle){ 4302 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4303 if (!sm_conn) return; // wrong connection 4304 sm_conn->sm_connection_authorization_state = AUTHORIZATION_DECLINED; 4305 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 0); 4306 } 4307 4308 void sm_authorization_grant(hci_con_handle_t con_handle){ 4309 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4310 if (!sm_conn) return; // wrong connection 4311 sm_conn->sm_connection_authorization_state = AUTHORIZATION_GRANTED; 4312 sm_notify_client_status(SM_EVENT_AUTHORIZATION_RESULT, sm_conn->sm_handle, sm_conn->sm_peer_addr_type, sm_conn->sm_peer_address, 1); 4313 } 4314 4315 // GAP Bonding API 4316 4317 void sm_bonding_decline(hci_con_handle_t con_handle){ 4318 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4319 if (!sm_conn) return; // wrong connection 4320 setup->sm_user_response = SM_USER_RESPONSE_DECLINE; 4321 log_info("decline, state %u", sm_conn->sm_engine_state); 4322 switch(sm_conn->sm_engine_state){ 4323 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4324 case SM_SC_W4_USER_RESPONSE: 4325 case SM_SC_W4_CONFIRMATION: 4326 case SM_SC_W4_PUBLIC_KEY_COMMAND: 4327 #endif 4328 case SM_PH1_W4_USER_RESPONSE: 4329 switch (setup->sm_stk_generation_method){ 4330 case PK_RESP_INPUT: 4331 case PK_INIT_INPUT: 4332 case PK_BOTH_INPUT: 4333 sm_pairing_error(sm_conn, SM_REASON_PASSKEY_ENTRY_FAILED); 4334 break; 4335 case NUMERIC_COMPARISON: 4336 sm_pairing_error(sm_conn, SM_REASON_NUMERIC_COMPARISON_FAILED); 4337 break; 4338 case JUST_WORKS: 4339 case OOB: 4340 sm_pairing_error(sm_conn, SM_REASON_UNSPECIFIED_REASON); 4341 break; 4342 } 4343 break; 4344 default: 4345 break; 4346 } 4347 sm_trigger_run(); 4348 } 4349 4350 void sm_just_works_confirm(hci_con_handle_t con_handle){ 4351 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4352 if (!sm_conn) return; // wrong connection 4353 setup->sm_user_response = SM_USER_RESPONSE_CONFIRM; 4354 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4355 if (setup->sm_use_secure_connections){ 4356 sm_conn->sm_engine_state = SM_SC_SEND_PUBLIC_KEY_COMMAND; 4357 } else { 4358 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); 4359 } 4360 } 4361 4362 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4363 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4364 sm_sc_prepare_dhkey_check(sm_conn); 4365 } 4366 #endif 4367 4368 sm_trigger_run(); 4369 } 4370 4371 void sm_numeric_comparison_confirm(hci_con_handle_t con_handle){ 4372 // for now, it's the same 4373 sm_just_works_confirm(con_handle); 4374 } 4375 4376 void sm_passkey_input(hci_con_handle_t con_handle, uint32_t passkey){ 4377 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4378 if (!sm_conn) return; // wrong connection 4379 sm_reset_tk(); 4380 big_endian_store_32(setup->sm_tk, 12, passkey); 4381 setup->sm_user_response = SM_USER_RESPONSE_PASSKEY; 4382 if (sm_conn->sm_engine_state == SM_PH1_W4_USER_RESPONSE){ 4383 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); 4384 } 4385 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4386 (void)memcpy(setup->sm_ra, setup->sm_tk, 16); 4387 (void)memcpy(setup->sm_rb, setup->sm_tk, 16); 4388 if (sm_conn->sm_engine_state == SM_SC_W4_USER_RESPONSE){ 4389 sm_sc_start_calculating_local_confirm(sm_conn); 4390 } 4391 #endif 4392 sm_trigger_run(); 4393 } 4394 4395 void sm_keypress_notification(hci_con_handle_t con_handle, uint8_t action){ 4396 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4397 if (!sm_conn) return; // wrong connection 4398 if (action > SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED) return; 4399 uint8_t num_actions = setup->sm_keypress_notification >> 5; 4400 uint8_t flags = setup->sm_keypress_notification & 0x1fu; 4401 switch (action){ 4402 case SM_KEYPRESS_PASSKEY_ENTRY_STARTED: 4403 case SM_KEYPRESS_PASSKEY_ENTRY_COMPLETED: 4404 flags |= (1u << action); 4405 break; 4406 case SM_KEYPRESS_PASSKEY_CLEARED: 4407 // clear counter, keypress & erased flags + set passkey cleared 4408 flags = (flags & 0x19u) | (1u << SM_KEYPRESS_PASSKEY_CLEARED); 4409 break; 4410 case SM_KEYPRESS_PASSKEY_DIGIT_ENTERED: 4411 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED)){ 4412 // erase actions queued 4413 num_actions--; 4414 if (num_actions == 0u){ 4415 // clear counter, keypress & erased flags 4416 flags &= 0x19u; 4417 } 4418 break; 4419 } 4420 num_actions++; 4421 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED); 4422 break; 4423 case SM_KEYPRESS_PASSKEY_DIGIT_ERASED: 4424 if (flags & (1u << SM_KEYPRESS_PASSKEY_DIGIT_ENTERED)){ 4425 // enter actions queued 4426 num_actions--; 4427 if (num_actions == 0u){ 4428 // clear counter, keypress & erased flags 4429 flags &= 0x19u; 4430 } 4431 break; 4432 } 4433 num_actions++; 4434 flags |= (1u << SM_KEYPRESS_PASSKEY_DIGIT_ERASED); 4435 break; 4436 default: 4437 break; 4438 } 4439 setup->sm_keypress_notification = (num_actions << 5) | flags; 4440 sm_trigger_run(); 4441 } 4442 4443 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4444 static void sm_handle_random_result_oob(void * arg){ 4445 UNUSED(arg); 4446 sm_sc_oob_state = SM_SC_OOB_W2_CALC_CONFIRM; 4447 sm_trigger_run(); 4448 } 4449 uint8_t sm_generate_sc_oob_data(void (*callback)(const uint8_t * confirm_value, const uint8_t * random_value)){ 4450 4451 static btstack_crypto_random_t sm_crypto_random_oob_request; 4452 4453 if (sm_sc_oob_state != SM_SC_OOB_IDLE) return ERROR_CODE_COMMAND_DISALLOWED; 4454 sm_sc_oob_callback = callback; 4455 sm_sc_oob_state = SM_SC_OOB_W4_RANDOM; 4456 btstack_crypto_random_generate(&sm_crypto_random_oob_request, sm_sc_oob_random, 16, &sm_handle_random_result_oob, NULL); 4457 return 0; 4458 } 4459 #endif 4460 4461 /** 4462 * @brief Get Identity Resolving state 4463 * @param con_handle 4464 * @return irk_lookup_state_t 4465 */ 4466 irk_lookup_state_t sm_identity_resolving_state(hci_con_handle_t con_handle){ 4467 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4468 if (!sm_conn) return IRK_LOOKUP_IDLE; 4469 return sm_conn->sm_irk_lookup_state; 4470 } 4471 4472 /** 4473 * @brief Identify device in LE Device DB 4474 * @param handle 4475 * @returns index from le_device_db or -1 if not found/identified 4476 */ 4477 int sm_le_device_index(hci_con_handle_t con_handle ){ 4478 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4479 if (!sm_conn) return -1; 4480 return sm_conn->sm_le_db_index; 4481 } 4482 4483 static int gap_random_address_type_requires_updates(void){ 4484 switch (gap_random_adress_type){ 4485 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4486 case GAP_RANDOM_ADDRESS_TYPE_STATIC: 4487 return 0; 4488 default: 4489 return 1; 4490 } 4491 } 4492 4493 static uint8_t own_address_type(void){ 4494 switch (gap_random_adress_type){ 4495 case GAP_RANDOM_ADDRESS_TYPE_OFF: 4496 return BD_ADDR_TYPE_LE_PUBLIC; 4497 default: 4498 return BD_ADDR_TYPE_LE_RANDOM; 4499 } 4500 } 4501 4502 // GAP LE API 4503 void gap_random_address_set_mode(gap_random_address_type_t random_address_type){ 4504 gap_random_address_update_stop(); 4505 gap_random_adress_type = random_address_type; 4506 hci_le_set_own_address_type(own_address_type()); 4507 if (!gap_random_address_type_requires_updates()) return; 4508 gap_random_address_update_start(); 4509 gap_random_address_trigger(); 4510 } 4511 4512 gap_random_address_type_t gap_random_address_get_mode(void){ 4513 return gap_random_adress_type; 4514 } 4515 4516 void gap_random_address_set_update_period(int period_ms){ 4517 gap_random_adress_update_period = period_ms; 4518 if (!gap_random_address_type_requires_updates()) return; 4519 gap_random_address_update_stop(); 4520 gap_random_address_update_start(); 4521 } 4522 4523 void gap_random_address_set(const bd_addr_t addr){ 4524 gap_random_address_set_mode(GAP_RANDOM_ADDRESS_TYPE_STATIC); 4525 (void)memcpy(sm_random_address, addr, 6); 4526 rau_state = RAU_SET_ADDRESS; 4527 sm_trigger_run(); 4528 } 4529 4530 #ifdef ENABLE_LE_PERIPHERAL 4531 /* 4532 * @brief Set Advertisement Paramters 4533 * @param adv_int_min 4534 * @param adv_int_max 4535 * @param adv_type 4536 * @param direct_address_type 4537 * @param direct_address 4538 * @param channel_map 4539 * @param filter_policy 4540 * 4541 * @note own_address_type is used from gap_random_address_set_mode 4542 */ 4543 void gap_advertisements_set_params(uint16_t adv_int_min, uint16_t adv_int_max, uint8_t adv_type, 4544 uint8_t direct_address_typ, bd_addr_t direct_address, uint8_t channel_map, uint8_t filter_policy){ 4545 hci_le_advertisements_set_params(adv_int_min, adv_int_max, adv_type, 4546 direct_address_typ, direct_address, channel_map, filter_policy); 4547 } 4548 #endif 4549 4550 int gap_reconnect_security_setup_active(hci_con_handle_t con_handle){ 4551 sm_connection_t * sm_conn = sm_get_connection_for_handle(con_handle); 4552 // wrong connection 4553 if (!sm_conn) return 0; 4554 // already encrypted 4555 if (sm_conn->sm_connection_encrypted) return 0; 4556 // only central can re-encrypt 4557 if (sm_conn->sm_role == HCI_ROLE_SLAVE) return 0; 4558 // irk status? 4559 switch(sm_conn->sm_irk_lookup_state){ 4560 case IRK_LOOKUP_FAILED: 4561 // done, cannot setup encryption 4562 return 0; 4563 case IRK_LOOKUP_SUCCEEDED: 4564 break; 4565 default: 4566 // IR Lookup pending 4567 return 1; 4568 } 4569 // IRK Lookup Succeeded, re-encryption should be initiated. When done, state gets reset 4570 return sm_conn->sm_engine_state != SM_INITIATOR_CONNECTED; 4571 } 4572 4573 void sm_set_secure_connections_only_mode(bool enable){ 4574 #ifdef ENABLE_LE_SECURE_CONNECTIONS 4575 sm_sc_only_mode = enable; 4576 #else 4577 // SC Only mode not possible without support for SC 4578 btstack_assert(enable == false); 4579 #endif 4580 } 4581 4582 const uint8_t * gap_get_persistent_irk(void){ 4583 return sm_persistent_irk; 4584 } 4585